- Paper Manual: Vol - CII

Disclaimer
© 2010,
All rights reserved. No part of this publication may be reproduced, stored in
retrieval system, or transmitted, in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the prior written permission from CIISohrabji Godrej Green Business Centre, Hyderabad.
While every care has been taken in compiling this Manual, neither CII-GodrejGBC nor Indian Paper Manufactures Association (IPMA) accepts any claim for
compensation, if any entry is wrong, abbreviated, omitted or inserted incorrectly
either as to the wording space or position in the manual.
The Manual is only an attempt to create awareness on energy conservation
and sharing of best practices being adopted in Indian and international Paper
industry.
Published by Confederation of Indian Industry
CII – Sohrabji Godrej Green Business Centre
Survey # 64, Kothaguda Post, R R District, Hyderabad - 500 084, India.
FOREWORD
The paper industry in India is more than a century
old. At present there are over 500 paper mills in the
country manufacturing industrial grades, cultural
grades and other specialty papers.
The domestic paper sector has posted an impressive
growth figure of 5 – 8% in 2009 – 10, in spite of the
global demand for paper declined by 8 – 10%. The
total installed capacity in the country now stands at
9.3 Million Tons per annum with a production of 8 million tons per annum and we expect the demand to increase to 10 million tonnes by 2012.
. The current per capita consumption of Paper in India is 8 kg per person compared to the
global average of 56 kg per person. Increasing literacy levels, current lower per capita
consumption and increased exports all contribute to a healthy rate of the growth of the
sector for a long period.
The paper industry in India is witnessing major capacity expansions during which conscious efforts are made to adapt state-of-art technologies. This leads to lower production
costs as well as lesser environmental impacts. The industry is also fast adapting ecologically sustainable practices like ECF bleaching, extended delignification, high pressure
cogeneration systems etc.
Globally, there is a consensus that Climate change represents one of the greatest environmental, social and economic threats which the planet earth is facing. Our Industry
being directly dependent on natural resources for raw material needs to act responsibly
in combating climate change. At the national level, business and industry will need to play
a major role by adopting an aggressive carbon reduction strategy. Also emerging are
financial incentives for Indian Industry to adopt low carbon strategies. Growing environmental concerns of consumers and the “greening” of business by responsible corporations have also started to compel products and supply chains to become more carbonsensitive.
Confederation of Indian Industry, CII-Godrej GBC has a vision of making India a Global
Leader in Green Business by 2015. To fulfill the vision, the Centre has adopted several
focus areas viz. Green Buildings, Energy Efficiency, Renewable Energy, Environment &
Recycling, Water management and Climate change activities. The centre also woks on
programmatic initiatives like the “Mission on Sustainable Growth” with the purpose of
promoting and championing sustainable growth in Indian Industry, without compromising on high and accelerated growth”. To advance energy efficiency in the industry, the
Centre through the exclusive Energy Efficiency Council facilitates industry adopt best
operational practices and thus become World Class Energy Efficient units.
We strongly believe that, to achieve the vision, it is necessary to demonstrate and achieve
leadership status in each sector, through creation of “Islands of Excellence”. The pulp and
paper sector was identified as a focus sector in the year 2007 and a road map was
adopted towards “Making Indian Pulp and Paper Industry World Class”. Significant improvement in the energy, water and environmental performance has been recorded by
some of the mills.
There is a pertinent need to have a neutral platform for sharing knowledge and skills
across the industry for the best practices. While the Papertech Conference series provide
this platform for face to face interactions the manuals on national and international best
practices serve as a ready reckoner for units towards achieving improved results. The
current manual is the third in this series.
I would like to express my gratitude to all the CEOs of the various Pulp & Paper mills in the
country for their contributions, guidance and support in shaping this initiative.
My congratulations to Mr K S Kasi Viswanathan, Chairman, Working group on ‘Make
Indian Pulp & Paper Industry World Class’ and all the members of the core working group
for their efforts and contributions.
I am sure that this best practices manual would go a long way in facilitating quicker
adoption of best practices in the Indian Pulp and Paper industry
Chairman - Energy Efficiency Council,
CII – Sohrabji Godrej Green Business Centre
And
Cheif Executive, ITC - PSPD
PREFACE
Globally, India is one among few countries where the
pulp and paper industry is witnessing rapid growth at a CAGR
(Compounded Annual Growth Rate) of 7 - 8%. With the increasing Globalization, the Indian paper industry is gearing itself to
become more competitive. This has necessitated Indian paper
industry to closely look at Efficient Global players operating outside India and elevate itself to International level in terms of
Efficiency and Technology. The problems of the industry are being continuously addressed at many forums and macro level policy decisions are under
consideration to make its operations competitive and sustainable.
A steering committee constituted in the Ministry of Power to prepare a framework document for “National Mission on Enhanced Energy Efficiency”, with the objective
of enhancing energy efficiency by putting in place new initiatives. The pulp & paper industry, being one of the 15 energy intensive sectors as identified in the Energy Conservation
Act 2001, also will have to adhere to the Energy Consumption Norms specified by the
Government.
The Perform Achieve and Trade (PAT) mechanism is a scheme that is being
designed to incentivise higher plant efficiencies. Since the additional Certified Energy
Savings can be traded with other designated consumers who could use the Energy Savings Certificates to comply with reduction targets, energy performance improvement will
make additional economic sense.
The World Class Energy Efficiency initiative of CII – Sohrabji Godrej Green Business Centre, namely ‘Make Indian Pulp & paper Industry World Class’ is an initiative
meant to enhance competitiveness by focusing on energy efficiency, good environmental
performance, Global best practices and technology upgrades. The objective of this initiative, with respect to the paper sector is to facilitate Indian Industry move towards world
class levels.
This initiative is driven by a core working group with participation of experienced personnel from Paper Mills, consultants and equipment suppliers. The core group
of experts visited ten select Indian paper mills and identified the best practices followed
there. These national best practices were documented in the first volume of this manual
series. The second volume contained the best practices identified/implemented in the
European paper mills, again by the same working group.
The next logical step is to see how far these identified Best Practices have been
put to use by select mills. In this connection the working group visited four mills namely
– Andhra Pradesh Paper Mills, ITC Bhadrachalam, Seshasayee Paper & Boards Ltd and
Tamil Nadu Papers Ltd. This manual, the third volume of “Best Practices Manual – Pulp &
paper Industry” contains the best practices identified in these units.
To take this initiative forward it is felt that a visit to well run paper mills in places
like China, Indonesia and Thailand will be of great help. Discussions are under way to
make these mill visits possible before the end of this year.
I take this opportunity to thank Mr Pradeep Dhobale, Chairman Energy Efficiency Council, CII - Godrej GBC for his unstinted support, CEOs of various Paper Mills for
their encouragement and the core working group members for their untiring efforts.
Mr. K S Kasi Viswanathan,
Chairman –Working group on
“Make Indian Pulp & paper Industry World Class” and
PAPERTECH 2010.
And
DMD, Seshasayee Paper and Boards Ltd.
Acknowledgement
It is our privilege to express our sincerest regards to Mr. Pradeep dhobale, Chairman – Energy Efficiency Council, CII – Godrej GBC and Mr. K S Kasi Viswanathan,
Chairman – working group on “Make Indian Pulp & Paper Industry World Class” for
their invaluable contribution by leading the initiative from the front.
We deeply express our sincere thanks to the managements of the host mills for
openly sharing the technical information with the working group and also for providing the local hospitality and support to the visiting working group members.
Also, the write ups provided for the identified best practices deserve a special
mention.
We take this opportunity to thank all the working group members who, inspite of
their bust schedules, have visited the four identified mills and with great zeal
identified the best practices. The list of working group members is attached as
annexure. We are thankful for the management of the companies to nominate
them to participate in the working group visits.
C O N T E N T
S
S.NO.
Chapter
Page No.
1.
Executive Summary
01
2.
How to use this Manual
08
3.
Profile of the visited Mills
09
4.
List of identified best practices
26
4.1.
Pulp Mill
28
4.2.
Stock Preparation & paper machine
61
4.3.
Soda Recovery & Power Block
70
4.5.
Utilities & Other Areas
98
5.
Action Plan & Conclusion
120
6.
Annexure
121
CII’s efforts in Promoting World Class Energy Efficiency in
Pulp & Paper Industry
EXECUTIVE SUMMARY
Paper industry in India is the 15th largest paper industry in the world. It provides employment to nearly 1.5 million people and contributes Rs 25 billion to the government’s revenue. The government regards the paper industry as one of the 35 high priority industries of the country.
In 1951, there were 17 paper mills, and today there are about 515 units engaged in the
manufacture of paper and paperboards and newsprint in India. The pulp & paper industries in India have been categorized into large-scale and small-scale. Those paper industries, which have capacity above 24,000 tonnes per annum are designated as large-scale
paper industries. India is self-sufficient in manufacture of most varieties of paper and
paperboards. Import is confined only to certain specialty papers. To meet part of its raw
material needs the industry has to rely on imported wood pulp and waste paper.
Growth of paper industry in India has been constrained due to high cost of production
caused by inadequate availability and high cost of raw materials, power cost and concentration of mills in one particular area. Government has taken several policy measures to
remove the bottlenecks of availability of raw materials and infrastructure development.
For example, to overcome short supply of raw materials, duty on pulp and waste paper
and wood logs/chips has been reduced. However, the aspect of higher production cost
needs to be tackled by the sector as a whole by increased cooperation in terms of sharing
of best practices and moving towards cleaner production.
The CII-Sohrabji Godrej Green Business Center (CII-Godrej GBC) under the
leadership of Mr. Jamshyd Godrej, Chairman, CII Godrej GBC and Managing
Director, Godrej & Boyce has adopted the vision of “Facilitating India to become a global leader in green business (environment) by 2015”.
Towards this objective, the Energy Efficiency Council of CII-Godrej GBC under
the chairmanship of Mr Pradeep Dhobale, Divisional Chief Executive, ITC Ltd,
PSPD has undertaken the development of “World Class Energy Efficient Units”
in energy intensive sectors, such as Cement, Power Plant and Pulp & Paper
1
Industry.
The Paper sector initiative through a project titled “Make Indian Pulp & Paper
Industry world class” is guided by a working group chaired by Mr. K S Kasi Viswanathan,
Deputy Managing Director, Seshasayee Paper & Boards Limited (SPB), Pallipalayam.
The activities were initiated in a CEO meet organized in conjunction with Paper Tech 2007
at Hyderabad, a national conference jointly done by CII-Godrej GBC and Indian Paper
Manufactures Association (IPMA). The CEO’s meet is attended by 19 CEO’s (details of the
CEO’s are given in the annexure A) representing all the major Pulp and Paper Manufactures in the country.
The CEO’s discussed and endorsed the following action plan to be taken up for developing
World Class Energy Efficient Paper plants in the country.
2
Core working group:
A core working group was formulated with participation for Paper Mills, consultants and
equipment supplier. The Paper Industry is sub divided into three groups namely Wood,
Agro and Recycled fibre group. These groups visited different paper mills, perceived to
be doing well in terms of energy, water and environmental management, and identified
best practices followed in those mills.
Inter plant visits for sharing and identify best practices (during August
2007 – February 2009)
The working group visited some of the Indian Pulp and Paper Industries in order to
identify the best practices. The companies to be selected are identified based on a questionnaire circulated to the above mentioned companies.
The plants visited by the working group are:
1.
APPM, Rajahmundry
2.
Bilt, Bhigwan Unit
3.
Delta Paper Mills Ltd., Vendra
4.
Hindustan Newsprint Ltd., Kottayam
5.
ITC – PSPD, Bhadrachalam
6.
JKPM, Rayagada
7.
Naini Tissues Limited, Kashipur
8.
Rama Newsprints and Paper Ltd.
9.
Shreyans Industries Ltd. (Ahmedgarh unit & Shree Rishab Paper)
10. TamilNadu Newsprint & Papers Ltd., Kagithapuram
About 6 to 10 working group members have visited each of the above mentioned plants
which had resulted in a great learning experience both for the host plant and the working
group members. The members of the working group are mostly Paper Manufactures,
Equipment suppliers and Consultants.
The out come of the working group plant visits is identification of 37 best practices from
the Indian Pulp and Paper Industry.
3
Development of “National Best Practices Manual”
The previous edition of this manual, namely “National Best Practices manual – Pulp &
Paper Industry”, was developed based on the leanings of the working group during the
visits to individual plants. The information collected was collated in to a document which
could be widely circulated through out Indian Pulp and Paper Industry.
It was envisaged that the manual would benefit both the participating and the non
participating companies. This would also initiate the process of sharing best practices
among pulp and paper Industry.
During Papertech 2008, the “National Best Practices Manual – Pulp & paper Industry”
was released on June 27, 2008 at Hyderabad. This manual was widely received and
appreciated.
The next steps in the process of “Making Indian Pulp & Paper Industry World
Class” were envisaged to be focused towards:
Implementation of the best practices by participating plants
Studying best practices in overseas installations
Development of International Best Practices Manual
Implementation of the international best practices
Make at least three Indian paper mills world class in three years (by 2010)
Second CEOs meet 27th June 2008
The CEOs of major Indian pulp & paper mills met again on 27th June 2008 on the morning
of first day of Papertech 2008 and reviewed the status of activities of the working group.
Having started with identifying Indian best practices for the pulp & paper industry, the
next step of bringing in the international best practices was taken up. In line with this, the
core working group met at Chennai subsequently to decide on which mills abroad should
be visited to identify international best practices.
After much deliberation, the core working group came to a conclusion that Scandinavian
countries and China have paper mills that are considered to be the best in a portion of an
integrated pulp & paper plant. As a first step, the Scandinavian countries were targeted
for identifying international best practices in Pulp & paper industry focusing on energy,
water and environmental management.
4
With the help of technology suppliers Andritz, GL&V and Metso, the working group could
visit the following mills in the five working days between 13 – 17 October 2008.
CII thanks the host companies Andritz Oy, GL&V and Metso, for their excellent hospitality
provided to the European mission attendees. This European paper mill mission was conducted by CII, in association with IPMA (Indian Paper Manufacturers Association).
The visit to the Chinese paper mills was planned but the working group backed out citing
apprehensions inline with the recent trend of economic downturn.
Development of “National & International Best Practices Manual”
The second volume of the manual, namely “National & international best Practices Manual
– Pulp & paper Industry”, contains two parts. While the National best practices were
collated from what some of the Indian mills have done differently in the recent past, the
International portion of the manual was developed based on the leanings of the working
group during the visits to European Paper mills. As with the first volume of the best
practices manual, the information collected is intended to be collated in to a document
that could be widely circulated in the Indian Pulp and Paper Industry.
5
Volume 2 of the best practices manual of the pulp & paper Industry was released on July
2, 2009 in the inaugural function of the seminar Papertech 2009 conducted jointly by CII
and IPMA at CII – Sohrabji Godrej Green Business Centre, Hyderabad. In Papertech
2009, together with sharing of best practices from the Indian Pulp & Paper mills, bringing
in more international experiences in the form of case studies and technological advancements was the focus. Thus the occasion of release of the manual can be considered apt
with its intent of the manual.
Inter plant visits for further sharing and identify best practices (during
February 2010 – May 2010)
Since the inception of the activities of “Make Indian Pulp & Paper Industry World Class” in
2007-08, some of the mills have done well to improve their energy, water and environmental management performances. Thus, the steering committee of the initiative guided
the working group to select the following four Pulp & Paper Mills to visit (or re-visit) and
identify the best practices implemented there.
1.
2.
Andhra Pradesh Paper Mills, Rajahmundry
ITC – PSPD, Bhadrachalam unit
3.
4.
Seshasayee Paper & Boards Limited, Erode
TamilNadu Newsprint & Papers Ltd., Kagithapuram
Development of “Best Practices Manual – Pulp & paper Industry, Volume 3”
This volume of the best practices manual, namely “Best Practices manual – Pulp & Paper
Industry”, was developed based on the leanings of the working group during the visits to
individual plants. The information collected was collated in to a document which could be
widely circulated through out Indian Pulp and Paper Industry.
The third volume in the series compiles the best practices implemented in the visited mills
during the last two years and contains their latest operational experiences.
During Papertech 2010, this volume of the “Best Practices Manual – Pulp & paper Indus-
6
try” was released on June 16, 2010 at Hyderabad.
The next steps in the process of “Making Indian Pulp & Paper Industry
World Class” were envisaged to be focused towards:
Implementation of the best practices by participating plants
Studying best practices in select Indonesian and Chinese Mills
Development of another International Best Practices Manual
Implementation of the international best practices
Continue to move towards the international standards in energy, water and environmental management.
7
HOW TO USE THIS MANUAL
The objective of this manual is to act as a catalyst to promote activities in Indian Pulp
& Paper Plants towards continuously improving the performance of individual units and
there by achieving world class levels (with thrust on energy, water & environmental
management).
To set a clear goal for improving the performance and move towards the world class
standards, the best practices adopted in some Indian Pulp & Paper Plants have been
included in this manual as part of “Best practices from Indian Pulp & Paper Industry”
The description of the best practices identified during the European paper mills visit
by the working group forms the first part of this manual. The details of the state of
the art technologies from the international paper plants have also been included
These best practices may be considered for implementation after suitably fine tuning to meet the requirements of individual units
Suitable latest technologies may be considered for implementation in existing and
future Pulp & Paper Plants for achieving the world class energy efficiency. Further
investigation needs to done for the suitability of these technologies for Indian conditions
The collated best operating parameters and the best practices identified from various plants need not necessarily be the ultimate solution. It is possible to achieve
even better energy efficiency and develop better operation and maintenance practices
Therefore, Indian Pulp & Paper Plants should view this manual positively and utilize
the opportunity to improve the performance and “Make Indian Pulp and Paper Industry
World Class”.
8
BRIEF PROFILE OF THE VISITED MILLS
9
THE ANDHRA PRADESH PAPER MILLS LIMITED
Details about the group
The Andhra Pradesh Paper Mills Limited (APPM) belongs to well-known industrial house of
the Bangurs of Kolkata. Other companies promoted by this group are Maharaja Shree
Umaid Mills in Rajasthan and the Peria Karmalai Tea & Product Co Ltd. in Tamilnadu,
besides many other businesses in Finance & Investment and charitable trusts.
Details about the unit
The mill was established as the Carnatic Paper Mills Ltd. way back in 1921 at Rajahmundry
on the banks of the River Godavari. It went into production in 1924 with a capacity of
3,000 TPA of paper.
It was renamed as The Andhra Paper Mills Company Ltd in 1956, when the states were
reorganized. The newly formed Government of Andhra Pradesh took over the company
with consequential change in its identity as The Andhra Paper Mills Ltd.
To help it grow and infuse adequate finances, a new Joint Stock Company under the name
of The Andhra Pradesh Paper Mils Ltd was incorporated in the year 1964 which took over
The Andhra Paper Mills Ltd.
The production grew over period of time and it now stands at a wood pulping capacity of
182500 TPA and paper production of 174000 TPA. An additional capacity of 55,000 was
added in FY 00-01 through the acquisition of Coastal Papers Ltd. (presently called as
Unit: CP)
Unit CP has a recycled paper based pulping capacity of 50000 TPA and an agro based
pulping capacity of 6500 TPA. Paper production capacity at Unit CP is 67000 TPA.
Besides these two units APPM has an off-site conversion center with conversion capacity
of 30,500 TPA at SN Palem near Vijayawada.
10
Brief description of the Process
The Mill under Mill Development plan (MDP) has implemented environment friendly state
of art technologies.
It has adopted down flow low solids continuous digester system for cooking the raw
materials. The chips are pre-steamed in diamond back chip bin and the cooking chemical
in the form of white liquor is added with weak black liquor (WBL) to the chips. Cooking
temperature is maintained at 150o C – 160o C. The cooked material is fed to 2 a stage DD
washer for washing. The washed pulp is then processed through a 2 stage oxygen
delignification (ODL) system.
The weak black liquor separated in the wash plant containing dissolved organic & inorganic is concentrated in multiple effect evaporators to 75% solids, before firing in the
recovery boiler. The inorganic coming in the form of smelt is dissolved in the weak white
liquor, known as green liquor. This green liquor is treated with lime at causticising plant
for making white liquor, a cooking chemical to use in digester house. The mill has lime
kilns to burn the lime sludge for producing burnt lime.
The washed ODL treated pulp is screened and supplied to paper machines for making
unbleached varieties of paper and also supplied to bleach plant. The ECF Bleaching sequence followed is Do-Eop – D1, with single stage DD washers provided between stages.
The pulp thus received from pulp mill is subjected to refining in which the cutting and
fibrillation takes place. In addition to this the stock is made by adding dyes and wet end
additives suitable for making required quality papers.
The mill has installed low Volume High Concentration (LVHC) Non Condensable Gases
(NCG) handling system for collecting NCG from evaporation plant and incinerating in the
lime kiln. Also, the mill has installed High Volume Low Concentration (HVLC) NCG handling system for collecting gases from tanks of evaporation plant, cooking and washing
plants. This has helped in reduction of odor in and around the plant.
Brief list of energy conservation projects implemented in last 3 years.
1.
Installation of energy efficient high steam pressure and temperature coal-fired with
high thermal efficiency. Increases in specific steam generation from 3.7 T/T of coal to
11
3.9 T/T of coal. Increase in specific power generation from 90 kWh/t of steam to 130
kWh/t.
2.
Installation of cooling tower for water circulation and conservation in Paper Machines
No.2 and No.3 Reduction in water consumption is 50 M3/hr.
3.
Replacement of high pressure steam ejector with medium pressure steam ejector in
34 MW turbine resulted in increased power generation of 30 kW
4.
Rising of de-aerator water temperature of coal fired boiler No.6 resulted in increase
in HP steam generation. Resultant increase in power generation is 160 kW
5.
Use of warm water in place of fresh water in DM water plant, reduction soot blowing
steam pressure in recovery boiler and installation of vent condenser for de-aerator of
recovery boiler No.4 resulted in reduction of steam consumption by 13 TPD
6.
Installation of flash steam recovery system of CBD system of recovery boiler No. 4
resulted in steam saving of 5 TPD
7.
Improved utilization of secondary condensate of evaporation plant, re-circulation of
pumps sealing water in fiber line and installation of Marx save all in stock preparation
resulted in reduction of water consumption in by 90 m3/hr.
Performance on the energy and water consumption front
Water (m3/ton) Power (kWh/ton)
2007-2008
2008-2009
2009-2010
91
90
84
1252
1247
1261
12
ITC BHADRACHALAM
Company Profile
ITC Limited - Paperboards and Specialty Papers Division - Bhadrachalam unit has
emerged as one of the most modern and contemporary players in the business worldwide. Unit Bhadrachalam offers a vibrant product range for packaging and graphic solutions such as Coated SBS Board (Pearl and Safire Graphic), Coated Folding Box Board
(Cyber XL Pac), Coated Board White Back, Coated Gravure Board, Coated Board Gray
Back & many more. The Unit serves thousands of customers in India and abroad & to a
wide range of industries from foods to personal products, office stationers to appliances
and accessories. It makes the complete range of paperboards that today offer unparalleled choice for FMCG packaging. During 2009-10, Unit Bhadrachalam has achieved turnover of Rs. 1539 Crore with production of 4.65 Lac tons of Paper & paperboards.
Technology Adoption
ITC Limited, Paperboards & Specialty Papers Division, Unit: Bhadrachalam had implemented Cleaner Technology in August, 2002 by investing Rs.225 crores and introduced
Elemental Chlorine Free (ECF) pulp bleaching for the first time in India. The successful
implemental of the latest technology had given enough confidence to implement the
world class bleaching technology called “Ozone Bleaching” as a part of mill development programme. In the year 2007-08, Unit Bhadrachalam implemented cleaner technologies to improve the overall environment with an investment of Rs.235 crores includes
•
A state-of-the- art 800 BD TPD super batch cooking system which saves energy and
is even more environmentally friendly.
•
A 400 BD TPD new fiber line consisting of the brown stock washing, screening, oxygen delignification and bleach plant.
•
Adoption of latest Ozone bleaching technology in Fiber line. With this Unit Bhadrachalam
became First Paper mill in India and 11th mill in the world to have ozone bleaching.
•
200 Kg/hr ozone generation plant from Wedeco-Germany.
•
Modification of Existing ECF fiber line-1 with Ozone bleaching stage.
13
Fuel switch from fossil fuel to biomass residues for power & process heat generation
by avoiding the non-renewable fuel consumption & helping for sustainability of environment.
Unit’s operations are automated with DCS along with advanced process control enabling precise control on quality of product, consistent production and monitoring resource consumption on real-time basis. Investments were made continuously to improve
quality, productivity and reduce cost.
Climate Change Strategy
Unit actively pursues Green House Gas (GHG) emission reduction through energy efficiency & large scale tree plantation through social and farm forestry initiatives. These
concerted efforts provide the company an opportunity to not only minimise the environmental foot print and energy cost but also gain from CDM by CER sale. Division has
registered seven projects with UNFCCC.
Unit Bhadrachalam has consistently reduced the specific energy consumption through
energy conservation and productivity improvement. Also, several initiatives are taken to
reduce GHG emission. Production of PCC (Precipitated Calcium Carbonate) by using CO2
released from Lime Kiln stack into atmosphere has reduced Carbon dioxide to atmosphere by 50% i.e 50-70 MT/day converted to PCC.
“ITC Social Farm Forestry” is a unique large-scale project – a first of its kind in India and
globally the only Afforestation/Reforestation project registered with UNFCCC with retrospective credits of 57792 CERs. (UNFCCC Registration No: 2241)
With the commissioning of Green Boiler the share of Bio-fuels has increased by 9% from
43% to 52% with continuous increase in biomass component in the fuel mix to reduce
carbon foot print.
During 2008-09, 2392 hectares were brought under Social Forestry plantations, expanding the cumulative total to 14,360 hectares. Unit has enabled cumulative plantation coverage of over 100,000 hectares. Plantation initiative not only led to sustainable sources of
raw material for paper & paperboard business, provided 40 million mandays of employment to tribals and marginal farmers and helped to sequester 3695 kilotons of CO2
thereby enabling ITC to become 235% carbon positive.
14
Environmental Performance
Lite ECF pulp mill with ozone and chlorine dioxide bleaching fiberline reduced AOX level in
waste water to less than 0.1 to kg/ton (i.e 0.0046 kg/ton in final treated effluent discharge) against the National norm of 1kg/ton with significant reduction in colour of effluent. The plant has achieved 100 % Solid Waste Utilization for the year 2009-10.
The odor control system is in existence since July 2008 by collecting high concentration
low volume (HCLV) NCG from areas like super batch digesters & evaporators and incinerating in lime kilns. ITC Bhadrachalam now going for Installation of HVLC (High Volume
Low Concentration) NCG System to further bring down the odor from present level with
process modifications.
In recognition of the commitment towards environment Unit Bhadrachalam was rated
with 5 STAR International rating in Environment by British Safety Council.
Awards
Unit has won numbers of awards in the field of environmental improvement, energy
conservation, safety and productivity improvement. Unit has won CII National award for
Excellence in Energy Management consistently for last nine years & Excellence in Water
Management for 2007, 08 & 09. Unit has been awarded by 5-Star Rating & Sword of
Honour in 2009 by BSC, Greentech Environment Excellent Gold Award 2007, 08& 09,
Bureau of International Recycling award for Wealth Out of Waste initiative.
Comparative study of Energy & Water Consumption
The unit continuously strives for reducing the specific energy consumption in every process / plant. The objectives include continuous improvement with maximum capacity
utilization of entire plant, adoption of energy efficient technologies / equipments, maximizing recovery of waste energy (Flash heat recovery), benchmarking with international
best practices & adoption of state-of-art technologies to be on par with international
mills. The Specific energy consumption has shown a downtrend in the recent years.
Specific power consumption (SPC) reduced from 1033 kWh/T to 954 kWh/T in 2006-07.
The increase in recent years is largely due to expansion & project activities going on
continuously in the mill. However, the SPC is reduced from 1092 kWh/T to 1050 kWh/T in
the year 2009-10, below the National benchmark level of 1100 kWh/T. Similarly specific
steam consumption reduced to 7.25 T/T from 8.0 T/T mark of 2004-05.
15
Specific water consumption is a continuous downtrend from 74 Cu.M/T to 50 Cu.M/T
(close to the International benchmark), is a result of the focused efforts made by the unit
for water conservation
16
CLONAL TECHNOLOGY AND AFFORESTATION
ITC Ltd-PSPD adopted clonal technology as a part of their responsibility towards society
and environmental amelioration determined to achieve self sufficiency in cellulose raw
materials.
With a mission to achieve improvements in productivity and profitability of plantations,
the company focused on genetic improvement of planting stock and improvement of the
package of practices. Major gains in productivity of eucalyptus plantations have been
achieved in the short span of 12 years through applications of cloning techniques for
gainful exploitation of existing useful variation.
The Bhadrachalam unit of ITC Limited-PSPD, a core sector, environment and ecological
conscious enterprise has been instrumental in development of a backward scheduled
tribal area. Conscious of their responsibility towards the society and environmental amelioration determined to achieve self sufficiency in cellulose raw materials has afforestated
420 million saplings in 1.0 lack ha(till March’10) and under farm forestry with
high-tech clonal plantations. The area planted under this plantation activity achieved selfsustainability of hard wood raw material supply to the mill.
GREEN BELT DEVELOPMENT: Extensive plantations have been done under green
belt Development for existing plant. Adequate attention is paid to the plantation of trees, their maintenance and protection.
Total Area covered under green belt
No. of plants planted
: 285.99 acres
: 5.87 lakhs
ITC – PSPD, Bhadrachalam unit is also a carbon positive company. The following table
shows the CO2 released and sequestered over the years.
Carbon Positive:
Unit
05-06
06-07
07-08
08-09
CO2 Released
Kilo tonnes
1202
1143
1352
1572
CO2 sequestered
Kilo tonnes
1244
2025
2638
3695
CO2 sequestered
Percent
104
177
195
235
17
Benchmark references
Specific Power Consumption & Specific Steam Consumption Benchmark
reference:
All About Paper, The life cycle of the Indian pulp and paper industry Green rating project,
Centre for Science and Environment, New Delhi.
Specific Water Consumption Benchmark Reference:
Final report on water conservation in Pulp and Paper Sector by NPC.
National benchmark : Chapter 7 - Formulation of Standards for Water Consumption /
Wastewater Discharge by Different Categories of Pulp & paper Manufacturing Mills, Page
No. 84
International Benchmark: Chapter 4 - Water Consumption Pattern in Other Countries,
Page No. 48, Table 14, Sl. No. 3 Europe
18
SESHASAYEE PAPERS & BOARDS LIMITED
The Company
Seshasayee Paper and Boards Limited (SPB), the flagship company belonging to ‘ESVIN
GROUP’, operates an integrated pulp, paper and paper board Mill at Pallipalayam, Erode638 007, District Namakkal, Tamilnadu, India.
SPB, incorporated in June 1960, was promoted by Seshasayee Brothers (Pvt) Limited in
association with a foreign collaborator M/s Parsons and Whittemore, South East Asia Inc.,
USA. After commencement of commercial production, having fulfilled their performance
guarantee obligations, the foreign collaborators withdrew in 1969. Main promoters of the
Company as on date are a group of companies belonging to the ESVIN group headed by
Mr. N Gopalaratnam.
SPB commenced commercial production in December 1962, on commissioning a 20000
tpa integrated facility, comprising a Pulp Mill and two Paper Machines (PM-1 and PM-2),
capable of producing, writing, printing, kraft and poster varieties of paper.
The Plant capacity was expanded to 35000 tpa in 1967-68, by modification of PM-2 and
addition of a third Paper Machine (PM-3). The cost of the expansion scheme, at Rs 34
Millions, was part financed by All India Financial Institutions (Rs 31 Millions).
In the second stage of expansion, undertaken in 1976, capacity was enhanced to 55000
tpa, through addition of a 60 tpd new Paper Machine (PM-4). Cost of the project, including cost of a Chemical Recovery Boiler and other facilities for enhanced requirement of
utilities, was estimated at Rs. 176 Millions. The same was part financed by term loans
from Institutions and Banks to the extent of Rs. 145 Millions and the balance out of
internal generation.
SPB undertook various equipment balancing and modernisation programmes, since then,
for improving its operating efficiency, captive power generation capacity, etc., upto 199293.
Expansion / Modernisation Project
The Company embarked on an Expansion / Modernisation Project to enhance its produc-
19
tion capacity from 60000 tonnes per annum, to 1,15,000 tonnes per annum and to upgrade some of the existing facilities, at an estimated cost of Rs 1890 millions.
The said Expansion / Modernisation Project was completed in December 2000. After
successful trials, the Commercial Production out of the new Paper Machine commenced
on July 1, 2000.
The current installed capacity of the Company stands at 1,15,000 tonnes per annum.
Raw Materials
The Company’s paper plant was originally designed for using bagasse, as the primary
raw material mixed with 20% bamboo fibre. Bagasse was being obtained from nearby
sugar mill on substitution basis using oil fired boilers.
With sharp increase in oil prices in 1970-71, the Company shifted over to the use of
hardwood, at the time of its expansion undertaken in 1978. Raw material mix underwent
a substantial change, with bamboo and hardwood forming 60% and 40%, respectively,
of its raw material consumption.
Soon Company started apprehending difficulties in procurement of bamboo. In 1981, it
added one more digester, to increase the share of the hardwood in the furnish mix to
80% and restricting bamboo use to only 20%.
With the commissioning of more wood based industries in Tamilnadu, there was again an
apprehension about availability of hardwood.
As a long term strategy, the Company at this time decided on restructuring use of bagasse which was seen to be the most reliable source of fibre for the entire Industry.
In 1984, the Company promoted Ponni Sugars and Chemicals Limited, as the captive
source for bagasse supply. It added bagasse handling systems and modernised PM-1 and
PM-2, to shift over to the use of bagasse.
The furnish mix for the existing Paper Machines of the Company is 55% bagasse and 45%
hardwood. The Company has vast experience in handling bagasse and is expected to be
one of the major strong points vis-à-vis its competitors in India, as the Indian Paper
20
Industry will continue to be bogged down by the problem of raw material availability.
For the new Paper Machine, the furnish is imported waste paper and imported pulp which
are sourced from far east countries, Europe and USA. A small quantity is supplemented
out of captive pulp production.
Exports performance
SPB’s exports are nearly 20% of its production and is a significant exporter in the Indian
Paper Industry. Due to its excellent export performance, SPB has been awarded ‘Golden
Export House’ status.
Awards
SPB is in receipt of various Awards awarded by Government of India, Government of
Tamilnadu, Industry Associations, etc. Some of the Awards received by SPB in the past
include:
•
Capacity Utilisation Award
•
Energy Conservation Award
•
Environmental Protection Award
•
Safety Award
•
Export Performance Award
•
Good Industrial Relations Award
•
TERI - Corporate Environmental Award
Environmental Protection
The Company attaches paramount importance to the conservation and improvement of
the environment. In its efforts to improve the environmental protection measures, the
Company has installed:
•
two Electro Static Precipitators for its Boilers to control dust emissions
•
an Anaerobic lagoon for high BOD liquid effluents
•
a Secondary Treatment System for liquid effluents and
•
an Electro Static Precipitator and Cascade Evaporator to the Recovery Boiler.
21
These facilities will ensure sustained compliance by the Company of the pollution control
norms prescribed by the Pollution Control Authorities.
ISO 9001/ IS0 14001 Accreditation
The Company’s quality systems continue to be covered by the “ISO 9001” accreditation
awarded by Det Norske Veritas, The Netherlands.
The Company has also been accredited with “ISO 14001” certification by Det Norske
Veritas, The Netherlands, for its Environmental Quality Systems.
Board Of Directors
The Company’s Board is broad based comprising 10 Directors:
•
Sri N Gopalaratnam, Chairman and Managing Director
•
Sri R V Gupta, I.A.S., (Retd.)
•
Dr S Narayan, I.A.S., (Retd.)
•
Sri Bimal Kumar Poddar
•
Sri Arun G Bijur
•
Sri V Sridar
•
Smt Sheela Rani Chunkath, I.A.S (Nominee of TIIC)
•
Sri Debendranath Sarangi, I.A.S (Nominee of Govt. of Tamilnadu)
•
Sri K S Kasi Viswanathan, Deputy Managing Director
•
Sri V Pichai, Director (Finance) & Secretary
Organisation
The day to day affairs of the Company are looked after by the Chairman and Managing
Director and supported by :
Sri K S Kasi Viswanathan, Deputy Managing Director and
Sri V Pichai, Director (Finance) & Company Secretary.
They are ably assisted by a team of qualified and experienced professionals in operations,
personnel, finance and marketing disciplines. ef Profile of Participating Companies
22
TAMIL NADU NEWSPRINT AND PAPERS LIMITED
Tamil Nadu’s 245,000 tonnes per year mill Tamil Nadu Newsprint and Papers Limited better known as TNPL, was incorporated on April 16, 1979 by the Government of Tamil
Nadu for manufacture of Newsprint and Printing and Writing Papers using bagasse as the
principal fibre source which is otherwise burnt as in-house fuel in the sugar mill boilers to
generate steam.
MILL DESCRIPTION
The Mill is situated at Pugalur, an industrially backward area in Karur District. The mill’s
production capacity now stands at 2,45,000 tpa. TNPL was procuring the raw material
requirement from the tied-up Sugar Mills located within a range of 5 - 140 Km from the
Factory, in exchange of steam for the supply of which TNPL had installed coal- fired
boilers at these Sugar Mills.
The mill development plan (MDP) to change the bleaching technology to Elemental Chlorine Free (ECF) involving Chlorine-di-oxide as the principal bleaching chemical has been
implemented and The Mill expansion (MEP) plan to increase the paper production capacity to 4,00,000 tpa is in progress with a financial outlay of 1000 crores.
The specific benefits of MDP are:
The technology of the existing mill operations is upgraded.
Outdated and environmentally obsolete pulping and chemical recovery equipment are
phased out.
Eco-friendly and state of art process technology is introduced by way of ECF bleaching
based on Chlorine di oxide for sustainable pulp and paper manufacturing.
Quality of pulp in terms of strength, run ability of the paper machines and brightness are
improved.
Competitiveness shall be improved on account of higher usage of improved quality of
wood pulp in the furnish. Improved overall environmental compliance is achieved in respect of the liquid effluent, air emissions and the solid waste discharges.
National Best Practices Manual - Pulp & Paper Industry
23
PROCESS DESCRIPTION
PULP MILL
The paper production capacity of 2,45,000 tpa is supported by the following 3 pulp lines.
1.
Hard wood pulp line 300 TPD with ECF bleaching.
2.
Chemical bagasse pulp line #1 180 TPD and
3.
Chemical bagasse pulp line #2 220 TPD
The chemical baggasse pulping lines employs ECF bleaching with a capacity of 500 TPD.
During Mill Expansion Plan(MEP) both the baggasse pulping lines will be integrated and
total pulping capacity will be augmented to 500 TPD.
PAPER MACHINE
The mill has 2 nos. dual purpose paper machines capable of producing newsprint/writing
and printing paper. The Paper Machine #1 (PM1) has a trim width of 6.8 M at a continuous
operating maximum speed of 750 m/min, while the PM2 has a trim width of 6.6 M,
capable of operating at speed around 850 m/min. The machine also incorporated several
improved features to support higher percentage of weak bagasse pulp in the furnish.
The erection of Paper Machine # 3 with a capacity of 1,55,000 tpa is under progress and
is scheduled to be commissioned by October 2010
CHEMICAL RECOVERY PLANT
The Black Liquor received from Pulp Mill is concentrated in the Black Liquor Evaporation
plant. The recovery plant has two streets of seven effects tubular type falling film evaporator.
One street has a capacity of 170TPH evaporation capacity at out put concentration of 4548%. The second new plant has a water evaporation capacity of 350tph at 70% solids
output. A new Recovery boiler with a capacity of 1300 TPD, 465oC at 65 kg/cm2 has been
commissioned in 2007 and is in operation. The liquor is fired in the Recovery Boiler at
70% concentration.
24
The Causticizing Plant has a capacity to produce 3600 m3/day of white liquor (NaOH +
Na2S).The recausticizing plant has a two stage slaking, which was introduced to overcome the problem of high silica bagasse liquor and a white Liquor Claridisc filter. The
smelt of inorganic from Recovery Boiler is dissolved in weak white liquor and causticized
with burnt lime to convert back to active alkali and the lime sludge generated from the
precoat filter. A new Lime mud claridisc filter has been installed to improve the dryness of
the mud which is fed to lime kiln. Two Lime mud reburning kilns each of 170 tpd capacity
, recycle lime sludge and re-generate burnt lime required for the causticizing process.
UTILITIES
The mill has five Service Boilers, four each of 60 T/hr steam generation capacity at 44 Kg/
cm2 and one 90 t/hr steam generation capacity at 64 Kg/cm². Erection of sixth Boiler
with capacity of 125 t/hr steam generation at 104 Kg/cm2 is under progress and is
expected to be completed by August 2010. The Mill has 5 turbines for captive power
generation of 81.12 MW.
A project to install a CFBC boiler with capacity of 125 t/hr steam generation at 104 Kg/
cm2 and a 41 MW turbine is under way and is scheduled to be completed by December
2012.
During 1993, TNPL has diversified into the field of Non-conventional energy sources, for
generation of electricity, mainly to reduce dependence on grid power. Under this programme
till date, the company has set up a 35 MW Wind Farm in Tamil nadu . The power generated from the wind farm is being sold to the TNEB.
The mill has a modern Effluent Treatment Plant designed to treat 20 MGD of effluent
generated from various sections of the mills. TNPL has Bio-methanation plants to treat
the high BOD/COD stream and generate biogas up to 40,000m3/day, which is utilised in
Lime Kiln, to partly substitute Furnace oil.
Performance on the energy and water consumption front
2005- 2006
2006-2007
2007-2008
2008-2009
2009-2010
Water in
kL/ton paper
Steam in
MT/ ton paper
Power in
kWh/ ton paper
104
109
108
91
67
6.72
6.69
6.47
7.65
7.84
1476
1461
1421
1518
1630
25
LIST OF IDENTIFIED BEST PRACTICES
Pulp Mill
1.
Integrated and non-Integrated Chlorine Dioxide generation plants – a comparative
study (APPM)
2.
Cent percent usage of debarked wood (ITC)
3.
Ozone bleaching system (ITC)
4.
Energy conservation through optimisation of cooking temperature in RDH (Rapid
Displacement Heating) process (SPB)
5.
Spray switch from hot to ambient water for final bleached washer in fiberline (SPB)
6.
Energy management- heat recovery from EOP filtrate discharge effluent (SPB)
7.
Reduction of Chlorine Dioxide in Bleaching stage in fiberline (SPB)
Stock Preparation and Paper Machine
8.
Reel moisture optimisation in QCS of paper machine -5 (SPB)
9.
Installation of energy efficient paper machine (TNPL)
Soda Recovery & Power block
10. Installation of Compact Disc Filter for white liquor clarification (APPM)
11. Indirect heating of Black Liquor and avoiding dilution with steam condensate (APPM)
12. Black Liquor Desilication By Flue Gas From Coal Boiler (APPM)
13. Installation of Advanced process controllers in various areas (ITC)
14. Installation of Green Boiler (ITC)
15. Steam management in high pressure Chemical Recovery Cogen plant (SPB)
16. Cycle efficiency enhancement in high pressure chemical recovery Cogen (SPB)
17. Optimization of soot blowing in high pressure chemical recovery Cogen (SPB)
26
Utilities and other areas
18. Water Management Practices (ITC)
19. Installation of mist cooling chamber in ETP (ITC)
20. Implementation of TPM practices (ITC)
21. Best practices in electrical switch gear installation (ITC)
22. Wealth out of Waste (ITC)
23. Particulate emission reduction through enhanced ESP efficacy scheme in high pressure chemical recovery cogen (SPB)
24. Water conservation in vacuum pump by reusing culvert water through save-all (SPB)
25. Water conservation initiatives (TNPL)
27
Best Practice No. 1
Comparison Between Integrated And Non Integrated Chlorine Dioxide Generation
Plants
Unit: Andhra Pradesh Paper Mills Limited
Background:
Chlorine dioxide (ClO2) is widely used as a bleaching agent and rarely as a disinfectant
because of its selective oxidation qualities. Chlorine dioxide is neither transported nor
sold off the shelf and thus has to be generated on-site. Chlorine dioxide has been the
subject of a great deal of research and in recent years new technologies and forms of
production have appeared, making this technique one of the most active and innovative.
Though many types of integrated and non- integrated processes are available for ClO2
generation, the chlorine dioxide production facilities at APPM are compared in this case
study.
ClO2 production at APPM
APPM is having one number of 3 TPD capacity integrated chlorine dioxide plant and
one number of 10 TPD non integrated Chlorine dioxide plant.
3 TPD integrated ClO2 plant is based on Munich Process, an integrated process of
producing from Hydrochloric acid. It comprises of Chlorine dioxide generation by reaction
of sodium chlorate with hydrochloric acid, electrolytic generation of sodium chlorate from
the liquor of the previous step and finally the dechlorination of the waste air. Sodium
chlorate electrolysis is equipped with 14 cells for maximum load of 26.5 kA. Integrated
Chlorine dioxide generation plant is equipped with single vertical generator having 6
compartments. ClO2 and Cl2 mixture is generated by adding HCl with Sodium chlorate
(NaClO3) in top compartment of the generator. The product gas, which is a mixture of
Chlorine and chlorine dioxide, is washed with chilled water ClO2 gas is absorbed in chilled
water in the absorption tower. Cl2 gas is treated in waste air dechlorination. Chlorine
dioxide concentration in water is 7-8 gpl.
28
10 TPD non-integrated chlorine dioxide plant is based on SVP-SCW Process. Main
equipment this process had are SVP generator, absorption tower, sesquisulphate filter
and sodium sulphate filter. ClO2 is generated by adding methanol to sodium chlorate in a
strong sulphuric acid solution. ClO2 gas is absorbed in chilled water in absorption tower.
The solid by product, sodium sesquisulphate is continuously removed from the bottom of
the generator and washed on sesquisulphate filter and fed to metathesis reactor. In
metathesis reactor, sesquisulphate is mixed with in a controlled manner to form slurry in
the tank. Slurry is pumped to sulphate filter. The filtrate i.e sulphuric acid is fed back to
ClO2 generator. The washed salt cake is pumped with pH control to Soda recovery furnace. Concentration of ClO2 solution is 10 gpl.
29
Installation cost
Installation cost of integrated plant is approximately 3 times more than the cost of
non integrated plant.
Operating cost
Operating costs of integrated and non integrated plants are about Rs.50/kg of ClO2 and
Rs. 75 per kg of ClO2 respectively. Operating cost of non integrated plant is mainly dictated by price of Sodium Chlorate which is imported overseas. Integrated plant is mainly
power intensive unit. As long as cost of power is low, integrated plant is economically
viable.
Operational Experience:
The operation of integrated plant is handled by two operators per shift. The operations of
the plant are carried out through scada system. Bearing little problems, the operation of
the plant is smooth and safe. Time requirement for resumption of production after shut is
about 5-6 hours. Periodical checking of oxygen and hydrogen content present in vent
gases of electrolysis unit is necessary.
Operation of non integrated plant is stable and easy. Plant is fully automated and is
operated through DCS. Plant can be switched over to production at desired concentration
of ClO2 within one hour. Plant efficiency is high and plant can be operated between 40%
-105%.
Factors to be considered while selecting the processes:
Size of the plant
Installed cost
Operating cost
Bleaching sequence adapted and end use of the product.
Environmental norms
Availability of power and its price
Supply of sodium chlorate crystals and price.
30
Summary of comparison
Integrated process
Non-integrated process
Chemical Process
Munich Process
SVP – SCW Process
Capacity
3 TPD
10 TPD
Raw Material
Hydro-Chloric Acid
Sodium Chlorate (Imported)
Power Consumption
8500 – 9500 kWhr DC/
ton of ClO2
Not significant
ClO2 concentration
7-8 gpl
10 gpl
Start up time
5 – 6 hrs
1 hr
Generation cost
Rs. 50 /kg of ClO2
Rs. 75 /kg of ClO2
Investment cost
High (three times of the other) Low
31
|
Best Practice No. 2
Cent percent usage of debarked wood
Unit: ITC – PSPD, Bhadrachalam
Advantaged of using debarked wood
Chipper house :
Less power/T of chips
-
3 kWh saving /T of chips
Increased life of knives
-
Apprx. 1000 MT more cutting per set
Less screen jamming
-
15 kg AA /T of blown pulp
-
Increase of 2-3 Mt per cook
Cooking section
Lower AA consumption
Lower cooking cycle time
More pulp/digester
Fiberline
More throughput
-
2 T/Hr increase in production rate
Better runnability of presses
-
Less vat pressure and better drainability
Less scaling
-
Reduced Ca2+ ppm from 15000 to 5000
Less bleach chemicals consumption - ClO2 2 kg/T and Peroxide 3 kg/T
Improved life of screen baskets -
40-50% Improvement
Recovery Island
Reduced furnace oil consumption in lime kiln by 5 kg/T saving
Improved performance of Evaporator (less scaling )
Cleaning period increased from 3 months to 6 months
Reduced solids in black liquor by 10-12%
Performance of CD filter filtration Improved by 10%
32
Best Practice No. 3
Ozone Bleaching Of Pulp
Unit: ITC, Limited
Background:
Use of Chlorine for bleaching in pulp manufacture is considered as a non-environmentally friendly process. Therefore, through adoption of ECF (Elemental Chlorine Free)
process of bleaching of pulp, gaseous elemental chlorine is cent percent eliminated.
ITC – PSPD Unit – Bhadrachalam is the first mill in the country to introduce ozone
bleaching technology for bleaching of pulp. Pulp Mill at ITC – Bhadrachalam has a design
capacity of producing 800 MTPD of blown pulp from super batch cooking plant. Fibre Line
#1, commissioned in the year 2002, has a design capacity to process 300 TPD of bleached
pulp and Fibre Line #2, commissioned in the year 2008, has a design capacity to process
400 TPD of bleached pulp. Fiberline #1 was initially designed for ECF sequence of D0EOP-D1 and retrofitted with ozone bleaching in the year 2008. Fibreline #2 has a bleaching sequence of Ze-DP.
33
Details of the identified best practice:
Ozone Bleaching Process Description:
Ozone bleaching is primarily a delignification stage; however some brightness improvement also takes place. The pulp from the post oxygen stage at a Kappa of around
10 – 11 and brightness of 42 – 45% is fed to A press after diluting with the backwater
from A stage. The backwater pH is maintained in the range of 2-3 to enhance lignin
selectivity and purge out metal ions before Ozone stage. A press is a special kind of press
which can deliver an outlet consistency of 35-40%. High consistency is essential for
efficient utilization of the Ozone gas in the subsequent reactor. At the top of the reactor,
the combined shredder/fluffer feeds the pulp to the Ozone reactor.
The fluffed pulp falls through the gas separator part of the reactor into the reactor
conveyor tube. In the tube there is a central axially mounted shaft with a large number of
paddle type blades mounted at a specific angle to the axis of the shaft. The action of the
conveyor is to lift, disperse and convey the pulp forward to the outlet of the reactor. This
design of reactor leads to high degree of bleaching and uniformity.
Ozone coming from the ozone generator is dosed at 12% strength in oxygen gas and
introduced counter currently of the pulp in the ozone reactor. In order to facilitate the gas
circulation counter currently, the gas is extracted in the opposite side by a speed controlled fan which achieves a light under pressure in the reactor.
The off-gases from the reaction contain oxygen around 75-80% and a very small
quantity of ozone (0.5%) which needs to be eliminated before the gases are released to
the atmosphere. The ozone destruction is done by heating the off gas to high temperature (300oC) in a catalytic destructor. Due to the fact that those gases also carry fibres,
the fibres have to be washed away prior to the gas heating to avoid the risk of fire. This
is done in fibre scrubber where gases are washed by an alkaline solution.
This pulp flows from ‘A’ press carries air into the reactor. It is necessary to maintain
this parasite air flow to a minimum value to avoid diluting the ozone gas too much, as this
would affect the yield of the delignification reaction. In order to control this air flow, there
is a second speed controlled fan which extracts the air from the tight shredder cover.
The e-stage is an extraction stage in which alkai is added to dissolve remaining lignin
fragments. Normal charge is 12- 15 kg/odt. Prior to the extraction stage, the pulp is
34
diluted in dilution conveyor so that consistency is adjusted to 6-7%. By addition of alkali
pH is maintained at around 10-11.
In order to increase the pulp temperature to 70oC, e-filtrate used for dilution is heated
using low pressure steam in a sparger connected to the dilution filtrate pipe.
35
Wash water is added to the press in accordance with the dilution factor and production rate. Excess filtrate is either drained or pumped to the filtrate tank of post oxygen
press depending on the calcium concentration in the system. About 50% kappa reduction
takes place in Ozone stage and brightness enhancement of 10-12% is achieved. 1 Kg of
ozone is practically found to replaces 4-5 kgs of ClO2 as active chlorine. 50% reduction of
ClO2 and peroxide consumption are achieved after ozone bleaching (refer table-2). A
significant improvement in strength properties is observed though viscosity is slightly on
lower side. Runnability and brightness stability on paper machines is also proven to be
improved.
36
Ozone Generation :
Ozone sometimes called activated Oxygen contains three atoms of oxygen and is the
second most powerful oxidizing agent next to fluorine. Technically production of Ozone is
through silent electric discharge of Oxygen rich feed gas using special generator. During
the ozone synthesis process oxygen molecules are initially split through the supply of
energy. The resulting oxygen atoms then react to create ozone with oxygen molecules
and release heat which must be dissipated by culling. Ozone formation takes place between two electrodes, which are isolated from each other by a dielectric made of glass or
ceramic and by a small gap. A high voltage, medium frequency, unilaterally grounded
alternating voltage is applied to the electrodes. The Oxygen gas flows through the gap,
resulting in ozone generation in the electric field.
The generator at ITC has a capacity to produce 200 kg/hr Ozone at 12% concentration and can reach upto 230 kg/hr at 10% concentration. The three pillars of Ozone
generation are Feed gas, power and cooling water. 1500 Nm3/hr oxygen compressors
supply 93% pure oxygen produced from onside VSA plant. Two chillers of 600 TR reach
serves the cooling water required. Specific power consumption per kg of ozone is 8-9 k
WHr.
37
Advantages of using Ozone for bleaching:
Specific Bleach chemicals consumption reduced
Better quality of pulp compared with earlier bleaching sequence
Significant reduction in AOX
Improved Standard deviation of final Brightness
Substitution of Imported hardwood pulp with mill pulp
About Rs 550 per MT saving in bleached pulp cost of production.
LP steam consumption reduced by 100 kg/T
Challenges :
The A stage press is prone to scaling if calcium content in the incoming pulp from PO
stage (Post Oxygen) is high. Calcium sulphate the oxalate scaling deposits on the low pH
38
loop which causes drop in press outlet consistency. Once the consistency drops below
35% from the ‘A’ press going to Ozone reactor the efficiency of ozone reactivity drops
drastically increasing the consumption of ClO2 and H2O2 in later stages. Better washing
and pH control of ‘A’ stage are very critical for avoiding scale formation in the system.
Calcium carbonate scale forms in the high pH loop of e stage if calcium content in the
incoming pulp is high. Though calcium carbonate scaling is easier to clean, it causes
reduction in dilution water flow due to deposits in backwater lines thereby reducing production rate. Use of anti-scaling chemicals prolongs the deposition rate but adds to the
production cost.
Due to the fact that calcium concentration is more in the backwater of e stage it
cannot be used for closure to PO stage thus increasing the water consumption in the
bleach plant and load on effluent. Continuous usage of 100% debarked raw material
been proven to give relief regarding calcium deposits.
Replication potential:
This project is replicable for expansion and modernization of large pulp and paper
mills to improve the environmental performance, energy conservation and operational
excellence.
39
40
Best Practice No.4
Energy Conservation Through Optimisation Of Cooking
Temperature In RDH Process
Unit: Seshasayee Paper And Boards Ltd
Background :
In the operating cycle of the RDH system, the batch digester is charged with chips and
packed with liquor or steam. The technique increases packing density by up to 10%,
thereby increasing pulp production per digester. The digester is then filled with warm
liquor of high sulfidity (lox active alkali) at 100oC. The elevated pressure in the digester
serves to uniformly impregnate the chips. The warm liquor is displaced with hot, white
and black cooking liquors. The digester is heated, and the cook continues to the desired
H-factor. At the end of the cook, displacement continues with washer filtrate until the pulp
temperature is below boiling point. The displaced liquor is collected in an accumulator.
The digester is discharged either with compressed air or by using pumping machine.
Special heat exchangers are employed to preheat the white liquor for the next cook to
about 155oC.
The pulp made via extended delignification was bleached to 90% ISO using 7.5% active
chlorine (11.7% for conventional kraft pulp). Caustic soda consumption decreased from
4.3% to 2.7%. Pulp strength properties were equal to or superior to the conventional
kraft pulp.
Unbleached and bleached pulp strength increased 10%. Displacement of the hot spent
liquor with washer filtrate is equivalent to a washing stage.
Process description
The RDH (Rapid Displacement Heating) digester utilizes the liquor displacement operation to optimize the cooking process.
The operation is divided into five separate steps:
41
A. Chip filling
B. Warm black liquor impregnation
Using warm black liquor from the warm liquor tank with a high sulphidity, a low alkalinity
and a temperature below 100oC the chips are impregnated in order to preheat the chips
and help accelerate the delignification during the cook.
C. Hot black liquor treatment and hot cooking charge
The hot black liquor from the black liquor tank is initially used for displacing the warm
black liquor without addition of white liquor in order to accelerate the delignification
during the cook. When a certain amount of black liquor has been added, hot white liquor
is pumped in together with hot black liquor from the HFL tank. The hot black liquor
treatment is intended to accelerate the delignification and improve the pulp quality and
yield.
D. Heating up and cooking
E. Displacement by wash filtrate and discharge
As the warm black liquor and the cooking liquor (a mixture of warm black liquor and hot
white liquor) are spent and subsequently displaced by the following liquid they are sent
either to the warm fill liquor or to the black liquor tank.
Heat exchangers are used to recover part of the energy used for heating the make-up
white liquor, and white liquor is being added to the hot black liquor to make up for
variation in the chemical loss.
Central to this scheme is a tight control of the chemical contents of the black and white
liquor. The RDH digester maintains a uniform distribution of chemicals during the cook,
but in order to determine the correct amount of white liquor to add it is necessary to
determine the alkali concentration of both the warm and hot black liquor as well as the
white liquor.
Without monitoring, the alkali changes can pass through and will cause considerable
variations in the Kappa number of the pulp, which can only be noticed once the cook is
42
finished and thus require additional bleaching chemicals or even be rejected. However if
the variation in alkali is detected, the addition of white liquor can be adjusted in order to
stabilize the situation.
The RDH (Rapid Displacement Heating) process makes possible extended
delignification. The RDH process has proven itself not only by cooking stronger, more
uniform pulp than conventional systems, but by significantly reducing energy and chemical costs at the same time. The RDH installation reduces the digester steam consumption
by 75-85%. Because the RDH cooking process removes more lignin from wood chips
than do conventional systems, less chlorine based chemicals are needed in the bleaching
phase (when cooking to lower kappa number) to bleach the pulps to 90% ISO brightness
than is needed in conventional kraft pulping. Caustic soda consumption is also decreased.
The fossil fuel consumption and the blow tank sulfur TRS emissions have been reduced.
43
In order to further enhance pulp strength as well as yield at Seshasayee Paper & Boards
Limited, it was decided to vary the cooking temperature in Rapid Displacement Heating
(RDH) process.
Objective:
The objective is to effect reduction in cooking temperature from 168oC to 158oC and
there by reduce steam consumption.
Classical Kinetic model for digestion process:
H-factor combines temperature and time into a single variable representing the extent of
the cooking and indicates the relative speed of lignin dissolution. It depends on cooking
time and temperature. H-factor’s dependency on temperature is very strong due to
44
delignification temperature dependency. Even a difference of couple of degrees in cooking temperature can make a big difference in pulp quality. H-factor has been defined so
that 1 hour in 100 °C is equivalent with H-factor of 1. While the delignification is assumed
to be one single reaction, the following equation describes the H-factor mathematically.
In other words, it is possible to leverage the additional capacity available in the
cooking system to reduce the cooking temperature. Lower the cooking temperature,
higher should be the time for cooking. To get the same kappa number (or extend of
cooking reactions).
Proposal:
Maintaining ODL temperature at 93°C (as against the earlier figure of 103°C, it was
decided to reduce RDH cooking temperature from 168°C by ~ 10°C(Fig.1). Kappa number is maintained at 20+.
Benefits:
By decreasing the cooking temperature, the following benefits were accrued.
Pulp (unbleached) yield had gone up by 5 % (from 44 % to 46%).
Viscosity of the pulp had increased by 5% (from 17 to 18).
Issues :
Since the cooking temperature has been decreased, cooking time had been extended
by 45 minutes.
45
Replication :
This concept can be used based on the quality of wood being used in that particular
mill. Also, lowering the cooking temperature results in increased reaction time and there
by increases the overall cycle time per batch. Care needs to be taken to ensure that this
aspect does not result in productivity loss.
Futuristic scope:
It is to be seen as to what extent the cooking temperature can be further lowered
without any adverse impact on productivity or quality of the product.
46
Best Energy Practice: 5
Spray Switch From Hot To Ambient Water For Final Leached Washer In Fiberline
Unit: Seshasayee Paper And Boards Ltd
Background:
After the implementation of Mill Development Plan in 2008-09, Seshasayee Paper and
Boards Limited operates the following
RDH Digester 4 No’s followed by 5 accumulators viz., warm, hot and White Hot. And
Heat Exchangers 3 No’s with option of Double Displacement Technology.
Three Stage Brown Stock Washing (Drum Filters)
Single stage Oxygen Delignification.
Pressure Screening
Elemental Chlorine Free (ECF) bleaching with D0, EOP and D1 Sequence
47
Details of the identified best practise:
Hot water spray was being advocated (as the system supplier designed it) for bleached
final washer, However, it was found that the final bleached pulp was quite warm resulting
in sizing problems in the stock preparation section. Hence it was decided to lower the
initial spray temperature. The beaching and the extraction process was not altered much
because of increase in steam addition in heater mixers.
Objective:
To effect reduction in Low pressure steam consumption, without affecting both the
beaching process and the chemical extraction in the washers.
Proposal:
Instead of hot water spray, it was decided to go in for cold ( ambient) water spray for
final bleached washer (Fig.1). However, it was not totally effective as the filtrate temperature had to be raised by using heat. Finally it was optimised at hot and cold water
mix ( in the proportion of 3:2 , for achieving the desired objective.
48
3
Benefits:
L.P. steam consumption reduced by ~ 45 TPD.
Pulp temperature dropped by 15 °C (Fig.2).
49
Spin-off gains:
Sizing problem minimised.
Issues:
None , as of date.
Replication:
This concept can be comfortably replicated in other pulp mills also.
Futuristic scope:
To be taken up by the Paper mill, on a case to case basis, after looking into the overall
pros and corns of the system in place.
50
Best Energy Practice: 6
Energy Management- Heat Recovery From EOP Filtrate Discharge Effluent
Unit: Seshasayee Paper And Boards Ltd
Background:
The bleaching stage of EOP stands for Alkali Extraction (NaOH) reinforced by Oxygen
and peroxide (H2O2). EOP Filtrate which is hot and highly alkaline is not allowed to be
discharged into the effluent without cooling or neutralising the same. It is a general
practice in the pulp mills to go in for a cooling tower where the hot EOP effluent is sent
after dilution or as such.
Objective:
To effect reduction in temperature of EOP filtrate prior to discharge, thereby protecting environment with saving in valuable L.P. steam consumption on a sustained basis.
Besides scaling and fouling of heat exchanger have to be curtailed.
Details of the identified best practice:
Seshasayee Paper after a wide round of discussions with International paper mills
and internal brain-stormming discussions decided to go in for heat recovery scheme
coupled with environmental compliance. As the input fluid was hot and highly alkaline
interspersed with fine fibres. Special Wide-gap Plate heat exchanger with or without
strainer was gone in for [Fig.1].
Fig. 1: Cross–cut view of Wide Gap Plate Heat Exchanger Plates assembled
51
A special heat recovery unit in the style of Wide-gap Plate Heat Exchanger (supplied
by ALIL –imported SS 316 plates) [Fig.2] was installed to cool the effluent leaving EOP
before discharging the same. The flow chart of the scheme in place is illustrated in Fig.3.
Fig.2 Wide-gap PHE in EOP Discharge area of Fiberline Unit
52
53
54
However, the scaling of the heat exchanger due to lowering of the fluid temperature
resulted in plugging and heat transfer impairment, alternate recourse for descaling was
resorted to. Dilute Sulphamic acid was added to the hot fluid before entry to the heat
exchanger and the treated effluent was circulated so as to minimise, if not avoid total
scaling of the heat exchanger.
Results
Through extraction of heat in otherwise waste hot effluent, the effluent temperature
is lowered from 75°C to say 50°C. the hot water generation for process use called for
lowered steam consumption requirement on a continuous basis.(Fig.4). The environmental gain in terms of lowered discharge effluent temperature did not call for dilution of
effluent with fresh water nor a separate cooling tower nor an elaborate neutralisation of
the same.
Benefits:
Drastic Reduction in L.P. Steam Consumption (2 TPH)
Scaling was minimal; heat exchanger efficacy is not lowered.
Effluent Dilution Avoidance; saving in fresh water.
Avoids installation of a Cooling Tower for environmental compliance (temperature of
effluent) and thereby non-release of Hazardous Volatile Organic compounds [HVOC]
to Atmosphere
Spin-off gains:
The effluent being near neutral and not warm can now be discharged as such without
the need of dilution with freash water nor the requirement of elaborate neutralisation .
Issues:
Initial issue of opening up the plates of WGPHE (Wide Gap Plate Heat Exchanger)
because of pluggage & scaling had been resolved through circulation with sulphamic acid
addition to the hot effluent before leading it to the heat exchanger. Also, the following
points needs to be taken into consideration.
Selection of heat exchanger should be done with utmost care. Usual Shell and Tube heat
exchanger cannot be used as the filtrate would contain fibres and fines.
Wide Gap Plate Heat Exchangers are costlier than a typical Plate type heat exchanger
55
EOP filtrate tends to scale a lt and hence a de scaling chemical dosage can be considered
mandatory.
Replication:
This concept can be comfortably replicated in other pulp mills also.
Futuristic scope:
Discussions are on with the designer of the special heat exchanger for achieving the
rated design efficacy of the wide-gap heat exchanger, so as to achieve low effluent discharge temperature and higher thermal conversion.
Fig.4. THERMAL PINCH-EOP Discharge HX
56
57
Best Practice No. 7
Reduction of Chlorine Dioxide in Bleaching stage in fiberline
Unit: Seshasayee Paper And Boards Ltd
Background:
Seshasayee Paper had gone in for ClO2 (instead of chlorine) for use in bleaching
process. Chlorine di oxide unit is designed and supplied by M/s ERCO (Canada).
Increasingly stringent regulations, are a major driving force behind innovation in the
pulp and paper industry. Clearly, the way to reduce dioxin, furan, chloroform emissions,
and AOX discharge is to reduce the chlorinated compounds used in the bleaching process. But because of variations from mill to mill, no universal answer exists. Differences
in pulping method, wood species, equipment, and desired pulp quality determine the
kinds of chemistry and process changes required.
As we rethink pulp bleaching, we see that hydrogen peroxide plays an evolving role in
the future of the pulp and paper industry. Traditionally, the use of hydrogen peroxide was
limited to the second caustic extraction stage or high-density storage or to provide 1-2
points of additional brightness. Seshasayee Paper and Boards Limited has reduced the
ClO2 by dosing peroxide in the ODL.
Objective:
To effect reduction in ClO2 consumption in bleaching stage.
Proposal:
It is proposed to go in for addition of 0.8 % Hydrogen peroxide in Oxygen Delignification
stage (ODL). With 3.5 kg/cm2(g) pressure and temperature at 93 °C, H2O2 reinforced
ODL is ensured (Fig.1).
Benefits:
ClO2 consumption reduced by 3 kg/T of pulp.
Kappa reduction achieved to the tune of 50%.
58
Post Oxygen Brightness increased from 43 to 47.
Final bleached brightness variability is also reduced.
No drop in strength noticed.
Spin-Off Gains:
Attendant reduction in steam consumption related to reduction in ClO2 generation
(though marginal) is ensured.
Issues:
None faced, as of date.
Replication:
This concept can be comfortably replicated in other pulp mills also. Hydrogen peroxide, added before the first bleaching stage, acts as a delignifying agent under high temperature (>75"C) and alkaline conditions, reducing the amount of chlorine dioxide required in subsequent stages. Depending on chemical costs, delignification with hydrogen
peroxide in ODL can be more economical than chlorine dioxide substitution.
59
60
Best Practice No. 8
Reel Moisture Optimisation In QCS Of Paper Machine -5
unit: Seshasayee Paper And Boards Ltd
Background:
Paper Machine 5 [PM5] is consuming significant amount of steam for its process,
more specifically in the Dryer Section. The operation was in manual mode with unavoidable variation in moisture in reel.
The moisture level in QCS was at 4.75% and had been oscillating by 1.1 per cent
point from the set point.
Objective
Productivity is maintained even with saving in fibre; through reducing the moisture
variation within 0.25 per cent point (5 %) from the set point.
Details Of Best Practice Initiated
The Dryer Deckle was 2.75 metres wide and the speed of the machine was 800metres
/minutes. Trial was conducted with 60gsm product.
The blend chest (Mix chest) level controller was tuned. The incoming Blend flows and
Consistency controls were tuned as required. The steam dryer controllers were also tuned.
The QCS control parameters were changed to suit the above. Refer the trend chart as
under. The Moisture in Reel was raised from 4.75% to 5.00% in final product. There was
no drop in product (fibre) quality.
61
62
Financials:
There had been practically no additional investment called for.
Benefits:
By fine tuning the controller in QCS and keeping the moisture content at 5 % -for a
60 gsm product- resulted in a saving of 0.4 to 0.45 TPD of finished paper. Financial gains
63
are estimated at around Rs 60 Lakhs/annum. As compared to the above, the saving in
steam of the order of a few lakhs is comparatively small.
Spin-off gains:
L.P. steam saving is just 3 to 5 TPD
Quality of final product is expected to improve with maintaining constant moisture
level through automation control.
Issues:
No issues, as of date.
Replication:
Certainly the concept of automation control raising the reel final moisture at a constant acceptable higher figure can be followed in other Paper mills.
Futuristic scope:
Though there is scope to affect further increase in Moisture in the reel, it had been
decided to stay put and try to stabilise the operation at 5 % moisture content in autosetting on a continuous basis.
64
Best Practice No. 9
ENERGY EFFICIENT PAPER MACHINE [ PM# 3]
Unit:
TAMILNADU NEWSPRINT & BOARDS LIMITED
Background:
Energy costs have increased consistently over the past few years and show no sign of
settling in the coming decade. In the wake of the increasing trend of the energy costs, it
is crucial of the paper makers to manufacture paper in an energy efficient manner. A key
aspect of energy efficiency in a paper machine is its design configuration. This best practice reflects on TNPL’s approach for energy conservation at design stage for their Paper
machine no. 3.
Project Profile:
TNPL’S Capacity expansion plan envisaged an increase in Capacity from the previous level of 245,000 TPA to 400,000 TPA with the addition of the new paper machine (PM
#3). This machine will be dedicated for the manufacture of SS printing and Writing paper,
copier paper, pigmented paper with bleached chemical bagasse pulp constituting 60% of
the over furnish, the balance 40% being fully bleached chemical mixed tropical hard
wood pulp. The pulping is of ECF bleaching system.
The proposed PM #3 will be a VOITH Fourdrinier paper machine with a top-wire
former, incorporating specific features favouring production of superior quality surface
sized printing & writing papers, copier and pigmented paper, with pre-metered sized
press.
Chemical Additive Plant:
The chemical additive plant adopts state-of-the-Art technology of M/s GAW, Austria
for preparation of wet end, coating and pigmenting additives. Care has been taken to
incorporate environmental friendly dust free material handling systems, usage of jumbo
bags for chemicals on power form and 1 Mt Containers for emulsions and other liquid
additives.
65
Stock Preparation:
The stock Preparation uses energy efficient low noise conical Metso refiners for refining hardwood and softwood pulps with automatic specific energy control mechanism and
on line vibration monitoring systems. Fiber recovery system uses a bag less poly disk
save-all with three filtrate zones generating cloudy, clear and super clear filtrates. These
filtrated will be entirely reused for pulp dilution, showers and for make-up thereby minimizing fresh water consumption. Broke handling systems are designed for handling both
regular broke and coated broke with extensive High density cleaners and screens before
being added along into the stock proportionating system in a constant ratio. The deaeration and cleaning system uses modern VOITH Vac de-aerator with high performance
4 stage centri-cleaners and slot pressure screens.
Head box:
PM #3 is equipped with a Dilution Head box Master jet F/B designed for achievement
of good fibre orientation profiles.
Wire section:
The wire section of the paper machine is a cantilevered type fourdrinier with duo
Former D supplied by VOITH, Germany.
Press section:
The press section is a bi nip Tandem Nipcoflex press with suction pick-up roll.
Vacuum section:
The vacuum systems employs Energy efficient Multistage and Single stage Vacuum
Turbo air blowers, extraction pumps and low vacuum fan.
Dry section:
The dry section of the machine has a Pre-dryer section with 6-dryer groups, first five
(5) dryer groups after press section with single tier group followed by one convectional
double tier arrangement.
66
After-dryer section has 2-dryer groups. The first dryer group after speed-sizer with
single tier group followed by one (1) convectional double tier arrangement
Size press:
Surface sizing (1.5-3.0 gsm/side)/pigmenting (4-6 gsm/side) and coating (future)
(up to 10 gsm/side) is done by a VOITH speed flow Metered Size press (SPEED SIZER AT)
Calendar:
Paper machine-3 is equipped with a two roll single nipped ECO-SOFT calendar.
The following Technical features are considered in regard of Green Technology while
selecting the machine
Heat recovery system in the dryer hood supply and return air. Future option for a Turbair
heat recovery system
No fresh water usage for Turbair plat compared to water ring pumps(closed loop)
Wet end chemical dilution with Super Clear Filtrate (SCF) for fresh water saving
SCF and CF showers at PM where ever feasible for fresh water saving
Separate sewer system at Speed Sizer for pigment recovery
Oil detection system in the cooling back water tank which indicates an oil leakage at a
cooling water consumer, no oil polluted water will be pumped to the cooler plant or to
further application in the process
Warmed cooling water return will be used as feed water for the warm water system for
steam saving
Shower water from Heat recovery units will be used again for the former exhaust flushing
for fresh water saving
White water heating for a better dry content
Motors Efficiency class 1 (EFF1 motors for 1-90 kW) for energy savings
Frequency converters for energy savings
67
VOITH Drives:
Water cooling for high torque utilization
Armature with permanent magnets for high efficiency
Hollow shaft with wide bore for material lead-through and mounting
Radial bearing
Terminal box for cable connection
Encoder if required
Revolver
Incremental encoder
Absolute encoder
Features of Voith Drives and benefits:
68
Other features:
Permanent magnet material
High temperature grease
Coating of rotor and stator
Sealing
Painting
Encoder system
Features of Turb-Air vacuum Blower
Several suction points connected to one nozzle/blower provides more flexibility at
small requirement changes
Vacuum nearly constant within capacity limits
Air flow variable
Specific power requirement
At-0.2 bar approx, 0.42 kW/m3/min
At-0.5 bar approx, 0.85 kW/m3/min
At-0.7 bar approx, 1.1 kW/m3/min
Energy cost approx, 10% lower than Water ring Vac pumps
Space requirement lesser compared to water ring Vac pumps
Noise 100 dBA high frequency, requiring isolation
Fresh water requirement Minimal
Heat recovery – Usable for heating process water /supply air to hood
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Best Practice No. 10
Installation of Compact Disc Filter For White Liquor Clarification
Unit: Andhra Pradesh Paper Mills Limited
Background:
In the recovery section of the paper plant after caustisization, sodium hydroxide has
been restored (in the liquor) and the liquor is once again white liquor. Before this can be
re-used the other product of the caustisizing reaction, calcium carbonate, called lime
sludge, must be separated off. Lime sludge is a grey substance that looks like mud or
clay. When it has been removed the white liquor is ready for use again in the cooking
plant or digester house.
Separation of lime sludge, white liquor clarification, is usually done by pressure filtration in tube filters or clarifiers. The lime sludge is diluted with returned filtrate (hot water)
and washed in pressure filters. It is then finally washed and thickened on lime sludge
filter of drum type.
In white liquor filtration, since maximum underflow density & maximum clarity of
white Liquor are the primary objectives, the unit type clarifier has obvious advantages.
The minimum turbidity in the clarified white liquor & maximum underflow density needs
to be delivered by the filtration unit where, generally, space is at a premium.
Details of the best practice:
Compact Disc-Filter is an efficient filtration method for white liquor clarification. Due
to In-built capability for lime mud pre-washing, subsequent mud washing stages are
reduced. Clarification of white liquor and washing of lime mud is based on efficient
displacement washing, where minimum water quantity is used. Lime mud dry solids
consistency is also much higher than any other white liquor clarification method can
provide. This means more opportunities when optimizing water balance around the recovery loop of the pulp mill.
Pressure difference, approx. 1.0 bar (14.5 psi), across will force white liquor through
the cake and filtering bags into inside of sectors. From there white liquor is led through
70
the shafts channels into the filtrate vessel. Lime mud that it attached on the surface of
the filtering discs rotates with the discs. At certain point hot water showers will pre-wash
lime mud cake during the normal filtration. After that pre-washed lime mud is scraped
from the discs with scraper plates to lime mud chutes. Dilution water will be led into the
same chutes and lime mud is directly diluted to storage consistency of 30 - 35%. From
the chutes lime mud is led through collection pipe to the lime mud slurry vessel. Constant
circulation is kept between lime mud tank and collecting pipe for equalizing lime mud
consistency effectively. Homogenous lime mud slurry will be pumped from lime mud
slurry vessel to a lime mud washer.
Capacity of the Compact Disc-Filter is controlled by level changes in the Compact
Disc-filter vessel. When the level inside the vessel rises the rotation speed of the shaft
will be increased. At certain point, when maximum rotation speed of filter shaft is reached
(6 rpm), the Compact Disc-Filter will have scraper diving sequence.
In scraper diving the scraper blades will be transferred into “in” – position so that the
outer section of the lime mud precoat will be removed, thus leading to better filterability
of the lime mud precoat. After scraper diving the scraper blades will be transferred back
to “normal” position and rotation speed of the discs will be dropped to the minimum. This
kind of a scraper diving will prolong the normal filtration sequence and ensure sufficient
capacity without the need of changing the whole lime mud precoat.
71
Advantages of the compact disc filter:
In modern pulp mill, the Compact Disc-filter provides, for example, following benefits
and opportunities:
Minimum water usage, pre-washing of lime mud is based on efficient displacement
washing in the Compact Disc-Filter
Pure white liquor with high temperature for cooking
Closed acid washing system
Hard metal scraper blades to resist against wearing
Maintenance kept in mind when designing the filter. Filtering sectors can be replaced
directly from the manholes
Non-plugging chute design to ensure problem-free removal of lime mud from the
Compact Disc-filter
Filtering discs are arranged in different sectors and these sectors can be replaced
through the manholes, which make replacement faster and more maintenance friendly
Operating parameters before and after installation at APPM:
Other advantages of a Compact Disc filter for WL filtration:
Compact Disc filter occupies less space in comparison to clarifiers, apart from offer-
72
ing advantages like augmentation of production, improved white liquor strength and
better white liquor clarity.
Replicability :
Installation of compact disc filter is an attractive proposition with a simple pay back
period of at most 3 years. This best practice can be replicated in any integrated pulp and
paper mill.
Other relevant information :
Low silica in lime and lime stone are desired. Dregs in Green Liquor should be less
than 50 ppm.
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Best Practice No. 11
Indirect Heating Of Black Liquor And Avoiding Dilution With Steam Condensate
Unit: Andhra Pradesh Paper Mills Limited
Background:
Prior to burning black liquor in a recovery boiler, it is heated to control combustion
liquor viscosity and liquor droplet sizing. Concentrated black liquor of about 75% total
dry solids is to be heated from about 98-99oC to about 120oC prior to incineration in the
recovery boiler.
Conventionally this has been done by direct contact steam heaters. Direct heating
with steam dilutes the liquor by about 2%. This in turn results in reduction of steam
generation from boiler and also condensate is not recoverable.
Typical arrangement for heating with direct injection of steam:
A shell and tube type indirect heat exchanger is installed in black liquor heating
system. The system is provided with necessary instruments for controlling the temperature of black liquor.
Disadvantages of Direct heating :
During direct heating steam along with condensate mixed into the liquor and the
liquor concentration will drop by about 2%.
Description of heat exchanger system for indirect heating:
A shell and tube heat exchanger with 106 tubes is installed. The heat exchanger has
3 compartments for liquor circulation. The space between the tubes is for steam chamber and arrangements are made for removing steam condensate. Water washing line
provided for cleaning the system.
The benefits of indirect black liquor heating are several folds. First is that the liquor
temperature can be maintained more closely than a direct unit, giving better control of
combustion and reduction of carry over. Second is that there is no dilution of the liquor
74
with steam condensate. This results in an increase in firing solids or evaporator/concentrator capacity and allows recovery of the clean steam condensate. Finally, the absence of
direct contact minimizes the risk of diluting the black liquor below the safe firing concentration.
In some heating systems black liquor is circulated to maintain velocity within the
heater at varying boiler operating rates. Further, the location of the heater downstream
of the boiler nozzle feed pumps and the use of the recirculation pump does not necessitate any change to the nozzle feed pumps. The additional pressure drop of the heater is
taken up by the recirculation pump. This pressure drop is minimized by the use of flow
enhancers inside the tubes which promote turbulence, allowing the total amount of
recircultated flow to be reduced.
The unit may be installed in either a slightly inclined horizontal position or a vertical
position. The orientation and piping arrangement must facilitate the removal and drainage of wash condensate or weak liquor from the heater.
How to maintain/ensure smooth operation of the indirect heating system:
Cleanliness of heat exchanger can be checked by observing the pressure drop across
the heater. Increase in pressure drop across heater, indicates fouling in the heater. Then
water boiling, dilute caustic boiling or manual cleaning is to be done to keep the heater
surface clean.
Though there is much advancement in the heat exchanger system to avoid any forced
stoppage of the indirect heating systems, on an average the heater is to be cleaned once
a month. During this period, either a stand by heat exchanger or the conventional direct
heating option can be used. The choice of installation of a stand by heat exchanger could
be made based on the frequency of cleaning and duration of each cleaning.
Originally these systems included two separate heaters; one heater in service with
the other on wash mode. Some opine that a spare heater is normally not necessary. If a
reliable backup, typically in the form of the existing direct steam heater, is available for
the short wash period, the spare heater is not required.
75
Benefits:
As a result of installing the indirect heating system, the mill may be able to reduce
capacity on an overloaded concentrator, or may increase steam production in the recovery boiler due to the higher heating value of the higher solids liquor. Furthermore, the
system provides less deviation from the temperature set point, providing a constant
viscosity to the liquor guns.
In the case of APPM, due to increase in black liquor concentration, the efficiency of
the recovery boiler has increased resulting in increased steam generation.
Cost economics (benefits and investments):
Cost of installation for the boiler of 1300 tpd dry solids firing is about Rs. 15 lacs.
Simple pay back period is about 2 years.
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Best Practice No. 12
Black Liquor Desilication By Flue Gas From Coal Boiler
Unit: The Andhra Pradesh Paper Mills, CP
Background:
The presence of silica in non-wood fibre causes major problems in the pulping process and limits the use of these feed stocks. Whether using soda or kraft processes, the
majority of the silica reacts with the hydroxide forming water-soluble ions. The content of
silicate in the spent cooking liquor (i.e., black liquor) ranges from 10 kg SiO3 per ton of
total dissolved solids when bagasse is the feedstock to 150 kg SiO3 per ton for rice straw.
Black Liquor, obtained from paper production using agricultural residues, contains
additional silica, which causes serious problems at filtration, washing, evaporation, burning, recausticizing and clarification levels of chemicals recovery. Partial desilication is
achieved by raw material cleaning. Straw dedusting is though a simple way of silica
reduction, but not efficient. Depithing of bagasse reduces silica in bagasse. Washing of
bamboo chips eliminates silica by about 50%.
The main problems associated with the presence of silicate ions in black liquor are:
scaling of the multiple-effect evaporator heat transfer surfaces
high black liquor viscosity which makes it difficult to concentrate the liquor
poor settling of lime mud and lower conversion of carbonate to sodium hydroxide in the
causticizing system
This project has been implemented in unit: CP of The Andhra Pradesh Paper Mills.
Details of the best practice identified :
When the alkalinity, i.e., pH, of black liquor is reduced, the silicate ion and a part of
the organic material in the liquor agglomerate to a colloidal form. When the pH is sufficiently low, it solidifies as amorphous silica and organic matter. The solidified matter can
be separated from the liquor by filtration or centrifugation. Low-purity carbon dioxide
(CO2) in the form of flue gas from the coal fired boiler has been used to reduce liquor pH
for silica precipitation.
77
De-silication Technique:
APPM, Unit: CP, a rice straw based pulp mill intends to install chemical recovery.
Since rice straw black liquor is rich in silica, chemical recovery of this black liquor is not
feasible without de-silication.
Carbonation is the most suitable technique for pH reduction of black liquor.
Controlled carbonation is the key to successful desilication as uncontrolled carbonation
leads to lignin co-precipitation.
Submersed Bubble Reactor technology adopted by CPPRI (Central Pulp & Paper Research
Institute) avoids localized carbonation and lower the pH in a controlled manner.
Black Liquor Circuit:
Weak Black Liquor (WBL) from Pulp Mill, is received at 6% solids & 70°C in to the
WBL Tank. It is pumped to Submerse Reactor Tank 1. Flow of the liquor is controlled with
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the help of Flow control Valve.
This black liquor is circulated by a high capacity and low head pump. The Flue Gas for
de-silicating black liquor is injected in the discharge pipe of this circulating pump. The
partially de-silicated black liquor from SRT 1 overflows by differential head into SRT 2.
In SRT 2 also the black liquor is circulated by a similar circulation pump and flue gas
is injected in its delivery. This further de-silicated black liquor overflows into the SRT 3. In
SRT 3 too, black liquor is circulated by a similar pump and final proportion of the flue gas
is injected in its delivery pipe. The finally de-silicated black liquor then overflows into the
Hot Retention Tank.
In Hot Retention Tank (HRT) liquor is kept in suspension by a slow speed agitator;
and kept hot by injecting steam.
From the HRT the liquor is transferred to feed well
of Black Liquor Clarifier by a screw pump. In the Clarifier, silica flocs settle down and clear
black liquor overflows from top of the overflow launder. It is transferred by a pump to
Black Liquor Polishing Tank.
In the BL polishing tank, the de-silicated black liquor is further clarified (sufficient
surface area and retention time are provided). The overflow is then pumped to Re-alkalization Tank, where caustic soda is added to regain the reduced pH, to go back to its
original value, in order to re-establish the colloidal stability of the liquor. From the
Realkalization Tank the black liquor overflows to the high pH Tank and from there pumped
to WBL Tank at Evaporators for further processing of water evaporation.
Flue Gas Circuit:
Flue Gas from Coal Fired Boiler is used as the source for the Carbon-di-oxide gas
required for de-silication. A Blower draws flue gas from the Chimney of Coal Fired Boiler
# 4. This gas is drawn before entering the Blower, through a seal tank where suspended
fine dust if any in the gas is scrubbed. The flue gas blower injects gas into the circulating
flow of black liquor of each SRT. Flow of the total flue gas is measured and controlled.
Foam Handling:
The foam generated in SRT 1, SRT 2, SRT 3 and HRT is routed to the Foam Tank.
Foam breaking steam nozzles, using Steam, have been provided. Foam breaker is mounted
on the top of the Foam Tank. A Transfer pump transfers the Black liquor collected at the
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bottom of the Foam Tank. A Screw Pump delivers the under flow slurry from Clarifier, to
the Filter Press.
Provision is made to send little slurry when needed, to SRT 2, for seeding purpose.
This helps in increasing the particle size of the silica during under carbonation, in-turn
improving the Filter performance. Suspended silica in the de-silicated black liquor is separated and washed in the Filter Press. This Filter Press is a 60 chamber, polypropylene
recessed, closed delivery type press, having a pull back closing device with motorized
power pack.
This silica slurry from the Clarifier Underflow is fed to Filter. The black liquor gets
filtered across the poly propylene filter cloth covered over the chamber plates and comes
out of the filter outlet as mother filtrate. It is collected in the Mother Filtrate Tank. It is
pumped to Black Liquor Polishing Tank. Provision is given to further wash the silica cake
of its entrapped liquor.
After washing and drying of cake, inlet valves are closed and Filter Press is opened
with the help of closing device. Then the chambers are opened one by one and the silica
cake is dislodged into a receiver. The filter cloth cleaned.
Operating parameters before installation:
Since the pH, RAA and total solid content are low, this black liquor is not suitable “as
such” for chemical recovery and de-silication. Pulping trials were carried out with
varying chemical charge, temperature and cooking cycle time.
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Table: Black liquor properties after modifying pulping conditions
Need / motive for installing desilication plant:
Calcium Aluminum Silicate present in liquor adds to viscosity of liquor.
It forms rock hard deposits on heat transfer surfaces; and beehives on Furnace Walls
during burning.
It slows down settling of Calcium Silicates during re-causticizing process.
Presence of silica leads to Low dryness of mud in causticizers during mud washing.
Thermal analysis studies showed that silica forms a sheath over lime particles so that
CO2 cannot escape from CaCO3 molecules, making Lime mud difficult to burn.
Improved operating parameters after the installation :
Table : Elemental Analysis Of Black Liquor
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Viscosity Of Black Liquor
Other relevant information:
This precipitated silica has following Industrial applications:
In ceramic Industry
In lubricating grease
In cosmetics
Reinforcing of rubber in rubber Industry
Replication potential:
This best practice can reduce the silica content in the black liquor from about 8 gpl to
a level of 1.5 – 2 gpl. Reduction in silica from 1.5 gpl is not proven to be achieved by
this method.
This best practice is most applicable to a straw based small & medium scale pulp mill
with recovery section.
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Best Practice No. 13
Implementation Of Advanced Process Controls
Unit:
ITC, Limited, Lime Kiln
Problem Statement:
Unable to reduce fluctuation of burning zone temperature due to long dead time associated
in the process between fuel oil flow and burning zone temperature.
Fluctuation in burning zone temperature which is not an optimized operation results in
more consumption of fuel oil per ton of product (lime).
Excess oxygen in flue gas being maintained on the higher side (> 5%)
Challenges being faced:
Long dead time cannot be handled by DCS level PID controllers.
Fuel oil flow affecting both burning zone temperature and excess oxygen in flue gas
which is a multivariable problem and same cannot be addressed by basic level controllers.
Disturbance in the unit demands for frequent changes in the operating parameters to
maintain the critical operating parameters with good judgment.
Solutions provided by APC:
Long dead time process can be effectively handled by model based Advanced Process
Controller.
Multivariable control problems can be addressed.
Control is based on models which derived from actual plant test.
Have the advantage of predictability (Feed Forward).
APC responds to disturbances in the plant and takes corrective action typically every
minute around the clock.
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APC in Soda Recovery Boilers
Problem Statement:
Fluctuation in excess oxygen in flue gas.
Excess oxygen in flue gas at higher side (>6%)
Maintaining primary, secondary and tertiary air ratios as well as excess oxygen in flue
gas which is a typical multi-variable problem.
Improve Steam per Ton of Black liquor solids by optimizing the overall boiler
operations
Challenges being faced:
Multivariable control problem cannot be addressed by basic level controllers.
Lack of feed forward information for better control on excess oxygen.
Frequent disturbances in the unit demands for frequent control actions to maintain
critical operating parameters.
Solutions provided by APC :
APC addresses the multivariable control problem to maintain both air ratios and
excess oxygen in flue gas.
APC takes corrective actions every 30 seconds for disturbances in the unit to maintain
excess oxygen close to the minimum allowable limit.
Smooth furnace operation which reduced the entrainment of solids. Entrainment of
solids will result in blockage of the flue gas paths and increased effort and time for
cleaning those during maintenance shutdowns.
APC in Power Block
Problem Statement:
Venting of steam due to frequent changes and mismatch in the supply and demand of
steam.
HP steam header pressure fluctuation and venting upon high pressure.
84
Challenges being faced:
Extensive coordination of different units required to keep venting minimum.
Frequent changes in supply and demand of steam demands for frequent control
actions. Loss of time to control result in loss of energy in terms of venting.
Optimization of TGs honouring power and steam demand which is a typical LP
problem.
Solutions provided by APC:
Any mismatch between supply and demand is taken care by changing load on CFB-6 &
CFB-7 by APC.
APC responds to supply/demand imbalance promptly and takes corrective action every
15 seconds round the clock.
Optimization of TGs can be achieved by inbuilt LP technology in APC.
Loading the most efficient TG to improve overall efficiency (Implementation going on)
Benefit:
Reduction in steam venting due to frequent and prompt corrective action by APC.
HP steam header pressure fluctuation has reduced which resulted in reduced HP steam
venting to a greater extent.
Optimized TGs operation which will result in reduced specific steam consumption per
MW of power.
85
Best Practice No. 14
Installation Of Green Boiler
Unit:
ITC, Limited
Background:
ITC PSPD Unit Bhadrchalam has series of coal fired boiler since inception. Unit was
retaining all the boilers in operation as plant expanded, keeping initial boilers as standby
boilers. Growing fiber requirement necessitated thought process backward integration
towards captive plantation through coloned varieties of select species of Eucalyptus and
subabul. Company has covered over 90,000 hectares of land for plantation to supply pulp
wood which can generate 10 Lac MT of wood annually.
Normally 20% of the plantation is the over ground biomass in the form of lops & tops,
bark and leaves. After the company stared using only debarked wood, farmers were
encouraged to debark the wood and transport debarked wood to the mill to avoid transportation of bark. Farmers in need of growing for next cycle of plantation has burnt all the
biomass generated.
Company has identified following opportunities on above back ground
The biomass left in the field has significant calorific value inspite of higher moisture
which can be used as fuel for boiler
Availability of biomass is continuously increasing due to continued thrust on plantation
as corporate policy for fiber security and carbon sequestration
CDM benefits by using green fuels.
Monitoring of GHG emissions.
To leverage the opportunity with changing scenario in terms of
awareness on GHG
emissions and opportunity to generate CERs, unit has conceptualized the idea of installing a bio fuel boiler called Green boiler.
This Green boiler is designed for 90 TPH steam generation, 64 kg/cm2 (g) pressure,
480±5 deg C super heated steam output designed for firing with 100% “ F” grade coal ,
86
70% Biomass + 30% Indian Coal. This boiler is a single drum design, natural circulation,
water tube, balanced draft, over bed cum under bed fuel feeding system, top supported
pressure parts and hopper bottom design.
Fuel combustion will be in an Atmospheric Bed Combustor (AFBC) fixed at the boiler
bottom. Fuel is stored in the bunker. Drag chain feeders are connected at the bottom of
surge hoppers. The fuel is fed by these feeders into the combustor by over bed feeding
system through coal spreaders. Also fuel is spread through under bed fuel feed pipes. For
biomass feeding pneumatic spreaders are provided.
The following are the various biomass which are being fired:
Wood bark
Lops and Tops
Chip dust
Lean wood
Cotton Stalk, chilli stalk etc.
Wood slivers
This biomass first passed through shredders to reduce them to the required size. The
finished biomass is sent to the boiler and fired. This has helped in reducing the coal
consumption to an extent of fuel switch by biomass.
Benefits of Green boiler include:
Has potential to generate good number of CERs per annum. A source of revenue.
The carbon foot print for manufacturing paper and paperboard reduces significantly to
the extent of substitution of coal by biomass
Reduction in annual coal consumption to an extent of fuel switch by biomass.
Opportunity to improve the efficiency of steam generation by not using old boilers
87
Best Practice No. 15
Steam management in high pressure chemical recovery CoGen plant
Unit: Seshasayee Paper And Boards Ltd
Background:
The 900TPD black liquor solids fired High pressure Chemical Recovery Boiler ( Fig.1)
is being operated at steaming conditions of 65 bar & 460oC with feed water temperature
at 135oC. The High pressure boiler is integrated to an extraction cum back pressure
steam turbo-generator for generating power and also to meet the process steam
requirements.The boiler is being operated at 65 to 70% load to suit the present requirements of the plant.
At present , about 70% of the steam extracted from the turbine is used for the
following applications:
Multiple effect evaporator
Combustion air preheating in Chemical recovery boiler
Deaerator steam requirements
The H.P.steam requirement for the soot blowing application is derived from the main
steam header of the boiler. Balance 30 % low and medium pressure steam are used for
process other than utilities.
In the Vertical air system of ANDRITZ design of Chemical recovery boiler, combustion air
is split in three stages and the same are being admitted at 3 levels. Whereas the primary
and secondary air are heated, tertiary air admitted at the highest of the 3 levels is unheated. The primary and secondary air is heated to the temperature of 200oC. This has
been achieved in three stage heating using HP, MP & LP steam.
In chemical recovery boiler, reasonably good bed stabilisation can be achieved in the air
temperature range of 150-200oC. Preheating the air temperature to the tune of 200oC
with the support of HP steam leads to increased energy consumption. There is an opportunity for optimising the primary and secondary air temperature and minimise the steam
consumption.
88
Objective:
To optimise the primary and secondary combustion air temperature in the chemical recovery boiler and minimse the steam consumption for combustion air heating.
Proposal:
The primary air temperature is gradually reduced from the set point of 200oC which was
as per the original design. Presently the air temperature is maintained in the range of
175-180oC.
HP steam utilisation has been totally avoided to achieve the temperature of 175-180oC.
The MP steam consumption also has significantly reduced. This has been taken up without affecting any of the operating parameters of the Chemical recovery boiler.
Benefits:
Use of HP steam has been totally eliminated for the heating application and utilised for
additional power generation.
Marginal reduction in MP steam consumption , since the air heating is lowered by 20oC
Spin-off gains:
The reduction in combustion air temperature has resulted in reduction in exhaust flue gas
temperature of the chemical recovery boiler.
Issues:
The plant operating team has observed no issues till today due to the reduction in combustion air temperature.
Replication:
The concept can be replicated in other pulp mills where the primary and secondary air
temperature is heated around 200oC.
Futuristic scope:
Secondary air temperature can be lowered gradually through adoption of stacked air
89
system. This would ensure high reduction in L.P. and M.P. steam consumption.
90
91
Best Energy Practice: 16
Cycle Efficiency Enhancement In High Pressure Chemical Recovery Cogen
Unit: Seshasayee Paper And Boards Ltd
Background:
Seshasayee paper and Boards Ltd has a high pressure Chemical Recovery Boiler with a
main steam parameters of 65 kg/cm2(g) and 460oC. The chemical recovery boiler is
integrated to a matching extraction back pressure cum steam turbo-generator. Turbine
steam extraction is at 11 kg/cm2(g) & exhaust is at 4.5 kg/cm2(g).
In a steam cycle the cycle efficiency increases with increase in steam pressure and temperature. However, for a turbine which is already in operation the increase in steam
pressure and temperature need to be within the tolerable limits of the turbine.
Objective:
To achieve high cycle efficiency through lower specific steam consumption for unit power
generation.
Process:
In Seshasayee paper Boards Ltd the following measures have been taken up by design
for improving the cycle efficiency of the plant:
Steam- side pressure and temperature drop across the main steam pipeline is designed
low so as to achieve the maximum driving potential through the turbine.
Generator with efficiency of more than 98% is selected.
Superheater heating surface is liberally designed right from Primary, secondary & tertiary
so as to ensure rated steam temperature on a continuous basis.
Designing and then operating at the highest main steaming conditions right from steam
–water circulating tubes ( 74 to 75 kg/cm2) encompassing the combustion chamber and
then through the superheater coils right upto steam turbine inlet ( 64 kg/cm2 & 455°C)
had ensured high cycle efficiency in terms of enhanced electrical power.
92
The concept of higher steaming conditions at the steam turbine inlet could be realised by
mixing the high temperature steam produced in coal fired boiler and comparitively low
temperature steam produced in the chemical recovery boiler but at the same operating
pressure. This can be achieved by mixing the steam in a common header.
Benefits:
Increased cycle efficiency due to higher temperature at the inlet of the turbine and hence
additional Power generation for the same heat input.
Issues:
There is no issue faced by the plant team as on date due to increase in steam temperature. The fear of high temperature corrosion had been negated through close to 2 years
of continuous operation of the boiler without attendant pressure part failure.
Replication:
This concept can be comfortably replicated in other pulp mills where the main temperature of
the chemical recovery boiler is lower. Increase the steam temperature of the coal fired boiler
operating at 64 kscg to say 485 – 490oC. Mix the steam generated at higher temperature in
coal fired boiler with the steam generated in Chemical recovery boiler.
Since the connecting header is common at the same main steam pressure, the resultant
mixed steam temperature can be raised to 460 to 465oC at turbine entry. The increased
steam temperature at the inlet of the steam turbine will increase the overall cycle efficiency.
The concept has also been successfully implemented in Andhrapradesh Paper Mills ltd. The
same concept can be extended to other mills who are having common steam pressure but
steam at lower temperature from chemical recovery boiler.
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Best Energy Practice: 17
Optimization Of Soot Blowing In High Pressure Chemical Recovery Cogen
Unit: Seshasayee Paper And Boards Ltd
Background:
A high pressure chemical recovery boiler is in operation. The main steam parameters are
maintained at 65 kg/cm2(g) and 460oC. There are several possible causes of deposits
over pressure part heating surface of Chemical Recovery Boiler. Plugging occurs because
of deposit accumulation. These deposits need to be periodically cleaned using soot blowers.
The deposits on the heat transfer surface of the boiler occur due to
1.
Physical carry over of the particles
2.
Fume condensation
These deposits occur in different areas of boiler.
Physical carryover
This is material that has been entrained in the flue gas. It produces a hard, fused deposit,
usually in the front parts of the superheater. Chemically, its composition is similar to
smelt.
Fume condensation
This material forms when inorganic vapours are cooled to their condensation temperature. This results in a very fine, soft deposit, usually in the generating bank and economizer. In the back side of the superheater, the deposits can be a combination of carryover
and fume. It all depends on the temperature profile of the gas, and characteristics of the
dust.
The two most important factors that determine whether deposits over pressure parts
accumulates, are the quantity of particulates in the upper sections, and the stickiness of
the same.(Fig. 1).
94
Fig.1
A third factor, soot blower operation also affects the operation as shown in the next
diagram. (Fig.2). Particulate removal efficacy depends not only on the type , quality and
quantity of deposits over pressure part exterior, but also on the soot blowing effectiveness , location, duration and time gap .
Fig.2
Objective:
To optimise the operation of the soot blowers based on the requirement and minimise the
steam consumption in the soot blowers.
95
Process:
STAGGERING THROUGH INTELLIGENT SOOT BLOWING CLUSTERING
As per the usual industrial operating practice, all the 28 soot blowers in the chemical
recovery boiler is operated once in a shift and all the 3 shifts in a day. The soot blowing
stretches for a continuous time period of 21/4 hours. In this practice, the soot blower is
put in operation even if there is no deposit formation on the heating surface. Operating
the soot blower without deposit formation will result in
increased steam consumption for the soot blowing operation
Erosion of boiler tubes
Based on the operational feed back, in order to improve the soot removal effectiveness, the blowing sequence was split into 2 clusters each of 14 No. of soot blowers. With
a time gap between the 2 clusters at 45 minutes, the soot blower operation from start of
the 1st unit to the end of the last (28th) unit extended to 3 hours. It was found that the
soot blowing efficacy in terms of removal of soot & stack clarity enhanced.
Without stopping at this, Seshasayee Paper operating personnel had gone one step
further in going in for further extending the soot blowing period by going in for Cluster of
4, with each cluster of 6 soot blowers, as detailed in Table -1.
Time gap between each of the Clusters of 45 minutes in between each of the cluster
affected a total time stretch of 4hrs 20 min.
Benefits:
The feed back is one of reduction in particulate emission through the stack. Longer
time stretch had enabled less solid particulate accumulation on the pressure part exterior. The improvement in soot blowing efficacy for particulate removal from pressure part
exterior could be accomplished purely based on operators feed-back and putting the
scheme in practice.
Issues:
No issues faced, as of date.
Replication:
Based on the operational success, other paper mills who had gone in for High Pressure
Chemical Recovery Boilers, can adopt similar technique as stated above in their units.
96
Fig.3
CHEMICAL RECOVERY BOILER # 11 - SOOT BLOWER LOCATION
TABLE - 2
REVISED EFFICIENT SOOT BLOWING SECQUENCE
97
Best Practice No. 18
Water Management Practices
Unit:
ITC, Limited
Background :
At ITC-PSPD all employees, including middle and top management, are fully involved
to give maximum thrust on water & resource conservation as it affects bottom line of the
main performance. In general, schemes with an investment up to 10 lakhs with a pay
back period of two years or less is implemented without loss of time and Unit Head is fully
empowered to take decision. Suitable rewards are given after the implementation and
displaying the envisaged savings. Water Conservation schemes implemented with the
ideas generated from external consultants are judiciously engineered and meticulously
executed. ITC-PSPD culture is to involve each and every engineer in every discipline as a
champion for faster execution of the job, thereby; the importance of Water & Resource
conservation is percolated to all workmen. Also, proposals are generated through employee involvement through suggestion scheme (TPM) which is linked with monetary
benefits.
As a result of consistent efforts for water conservation, Specific Water Consumption
has reduced by over 33% from 74 m3/T in 2004-05 to 50 m3/T in 2009-10.
98
Major Water Conservation Projects:
A number of projects were taken up for reducing fresh water usage at various sections of the plant & some of them are listed in the table below. The underlying principle
behind these ideas is 3 R’s – Reduce, Reuse & Recycle.
S.No.
Project Description
Water Saving
(m3/day)
1
2
3
4
5
6
7
8
9
10
11
Installation of disc filter for generated back water
reuse purpose at PM-5
1200
Installation of Top layer disc filter for recycling of back
water from top layer wire for reuse of total water in
the system at PM-5
1200
PM-4 excess clear filterate water reusing at NSFT–B
pulper slushing.
1719
Petax water reuse for all HP showers & pump sealing
at PM-1
1000
Evaporator -3 & 4 condensate reusing at washing &
bleaching of NFL
1000
ETP Back water line commissioned for floor cleaning
at Paper Machines, NFL-1 & 2, ClO2 plant, SR Plant,
Voltas Chiller and Oxygen plant and fresh water
lines dummied.
1540
Cloudy overflow taken to clear filterate chest to maintain
white water towers, thus avoiding usage of fresh water to
maintain white water tower level at PM-6.
500
All the hydra pulpers are provided with back waters from
machine 5 various layers at PM-5
500
Lime Kiln-2 mud filter sealing water collection & recycling
through fanless cooling tower and same reuse for mud
filter & scrubber.
500
DM plant Ultra filter return water recycling to
Clarifloculator.
500
CFBs Ash conditioner water changed from Process water
to Back water
200
99
12
13
14
15
16
17
18
PM-1,2 & 3 hydraulic stations ,& vacuum condenser
cooling water collected and reusing at PM-2 & 3 high
pressure showers
400
PM4 & PM 5 additional back waters are diverted to
NSFT by increasing the line size from 100 mm to 150 mm.
350
collection of Evaporator-4 pumps sealing water,
Reusing as make up Fresh water for cooling
tower at Evaporator -4
648
Collection of returning the SRP-4 spout cooling heat
exchanger water and boiler pressure part sample
analysers cooling water (swas panel) to reservoir.
350
ET back water line laid from CSP 2B clarifier to CD Filter
for floor cleaning
240
PSM back water being used for A stage dilution factor in
both fiberlines
338
TG-5 Sand filter back wash water recycling to Clarifloculator
100
100
101
Water collected from PM-1,2& 3 Hydraulic Stations reused for High pressure showers
Methodology adopted for Water Conservation Projects :
Energy cell along with departments identify the opportunities to conserve water through
reduction, reuse and recycle opportunities.
Proposals are classified into three categories
•
Proposals identified or suggested by employees, which require minor modification &
investment less than 10 Lac are taken up & implemented immediately.
•
Proposal identified by Energy cell and departments are raised as capital scheme for
value above Rs. 10 Lac – 100 Lac
•
Proposals which are integrated with process and with investment more than Rs. 100 Lac
are taken through projects for initiation and implementation
Energy Cell prepares the concept note of the proposal identified with investment and
payback
Department approves the concept note agreeing for implementation of proposal and
budget requirements.
Energy Cell prepares the capital scheme based on concept note and submits to Divisional
Management Committee for approval of funds for implementation.
Approved scheme is submitted to department for implementation
Energy Cell co-ordinates with department for implementation of proposal
On implementation, Energy Cell monitors the savings achieved against the envisaged
savings and reports back to department.
Scheme is closed as implemented when report is submitted to Finance on status of
capital scheme.
To monitor sustainability of savings, Energy Cell monitors the savings on monthly basis
for one year to confirm the savings.
Apart from the above water consumption reduction initiatives, a project was taken up
for un-metered reduction throughout the plant. The project resulted in considerable fresh
water saving of 5300 m3/day which was going un-metered because of the water leaking
through underground old network of fresh water & fire hydrant pipelines.
Methodology adopted for reduction of un-metered water :
A step by step approach was taken for the project involving following steps
102
Extensive evaluation was done to figure out the unmetered water
Measurements were made from supply point to various end user points
Meters were installed at various places, where there was no sub-metering arrangement.
Old meters were replaced with new accurate MagFlow meters.
The metering system was integrated with the advanced IP-800 Dashboard system to
monitor the water consumption on real time basis.
The major reason was the water leaking through underground old pipelines. The seeping
water was going as un-metered.
Action taken:
The whole underground network of pipelines was eradicated & new overhead connections were provided for all the areas
103
Best Practice No. 19
Installation Of Mist Cooling Tower At ETP
Unit:
ITC, Limited
Background:
Effluent Treatment Plant upgraded with the new MBBR Technology in the year 200809.The overflow from Primary Clarifier (Coloured effluents) is led to MBBR tank to further
reduce soluble COD by 40-60%. The outlet of MBBR will move to Aeration tank and then
to Secondary Clarifier for further reduction of pollution loads. To reduce the Inlet temperature to MBBR Tank cooling Tower introduced in the month of April’2010.
Details of the identified best practice:
Mist cooling provides an efficient alternative to cooling towers. The technology uses
recirculation pumps to draw water from a shallow pond (approximately 3' deep) and
propel it through nozzles at high velocities. The intensely atomized particles (subdivided
to around 5 μm) rise about 25' above the nozzles to create a cooling mist. As they rise,
the water particles develop a resonance that allows them to repel other water particles
and prevents them from coalescing. The surface evaporation occurs quickly — faster than
the water can reach equilibrium. As a result, mist cooling is able to provide an approach
to WBT of 0 to 1°C with a temperature drop of 12 to 15°C.
104
Due to increase in “T, water quantity required at the process side is much less. MCS
requires water pressure equivalent to the height of cooling tower as shown in the following diagrams. Hence, considerable amount of energy is saved on circulation water pumping. Also, MCS does not require any fans for cooling. Thus, a huge amount of energy is
saved on circulation and cooling.
Mist Cooling System will supply cold water temperature with an approach of 0 to 1°C
to WBT as against an approach of 4 to 6°C in cooling tower. For plants with space constraints, a closed pond can be used. The approach to WBT increases to 2.5°C with a
closed-pond design, but a closed pond is 30 to 35 percent smaller than an open pond.
Mist Cooling Systems can have chokeless design with the size of smallest opening in
MCS is more than one inch (25 mm) in diameter. Hence chances of particles choking the
system are low. Another benefit of mist cooling is reduced maintenance requirements.
While cooling towers use louvers, fan blades, clamps and other components that must be
replaced, mist cooling systems do not have any moving parts and therefore require little
maintenance. Shallow mist cooling ponds also are easier to clean than the deeper ponds
required for cooling towers, and ponds can be designed with two or three compartments
to provide additional maintenance flexibility.
Drift losses are 0.1% for normal conditions and 0.25% for Windy conditions. These
can be further reduced to 0.05% by adopting our closed pond design. Evaporation loss
will depend on the temperature drop obtained from the system.
Chemical dosing, makeup water and blowdown requirements are similar to what is
required with cooling towers. However, the atomization in mist cooling, along with the
related absorption and retention of air by the water particles, allows the water to have
better biochemical oxygen demand (BOD) and chemical oxygen demand (COD) values
than the water in cooling towers.
105
Replication potential:
Mist cooling system can be installed in any paper mill.
Mist cooling systems have been installed in The West Coast Paper Mills, Dandeli and
more recently in Orient Paper Mills, Amlai.
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Best Practice No. 20
Implementation of Total Productive Maintenance (TPM) Practices
Unit:
ITC, Limited
Total Productive Maintenance (TPM) is a maintenance program which involves a newly
defined concept for maintaining plants and equipment. The goal of the TPM program is to
markedly increase production while, at the same time, increasing employee morale and
job satisfaction. TPM brings maintenance into focus as a necessary and vitally important
part of the business. It is no longer regarded as a non-profit activity. The goal of TPM at
ITC PSPD is to improve & sustain productivity through people.
At ITC PSPD, Implementation of TPM involved top management commitment and
employee participation. Management commitment was vital as the process was long
drawn and took huge effort to create awareness and gain employee acceptability to
participate in the program as most of the employees are less educated and from backward areas of the region. For employees, the challenge was to change their traditional
mindset, it was a process of moving away from minimum work mentality to maximum
contribution through participation, for which ITC PSPD has do everything possible to
justify for the change.
At ITC PSPD, TPM gave opportunity for all the employees to engage along with management in fulfilling the business objectives through their contribution at workplace by
leveraging their strengths. In the process, employees are empowered to pinpoint the
problem areas, prepare a detailed course of corrective action, and initiate the corrective
process. Employees are grouped as teams and are encouraged to work on small problems and keep meticulous records of their progress. Successful completion of the team’s
initial work is always recognized by the management. Publicity of the program and its
results was done to make the program a success. Once the teams are familiar with the
TPM process and have experienced success with a small problem, problems of ever increasing importance and complexity are addressed with same teams. In the course of
action, employees felt better due to their contribution and their self image improved and
their attitude is no longer be “I am just an operator”
In the course of journey, ITC PSPD employees are started taking ownership of the
equipment/ machines they are operating, the results of performance are displayed at
respective shop floor on monthly basis to demonstrate their contribution.
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The process gave an opportunity for ITC PSPD employees to contribute through their
rich experience and innovative ideas and enabled others to be part of success as the
activities are carried out in the form of teams. This has created good team and healthy
competitive spirit. At the same time, it improved relationship between employees and
managers due to active cooperation and support in solving the problems.
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Best Practice No. 21
Best Practices in Electrical Switch Gear Installation
Unit: ITC – PSPD, Bhadrachalam
Background:
Since in any INTEGRATED PULP & PAPER plant lot of traces of chlorine di oxide & other
corrosive fumes which will spoil the power & control panels if they are located in close
periphery of the presence of these fumes .It is a very good practise to house all power &
control equipments in a separate building which will facilitate a very good environment &
can give better life of all electrical panels fallowed by a good trouble free service which
will enhance the bottom line of the company.
Also design engineer should ensure that cable losses shall be confined to only 2.5% only
& accordingly we must size the cables to take care of starting voltage drop & losses to
very minimum. It is also to be noted these panels are having lot of costly items which are
responsible for all controls of the plant, if they are climatised to a fair amount will lead to
very high uptime of plant running followed by high reliability of plant in operation.
At ITC-PSPD, UNIT BHADRACHALAM all electrical rooms are located in a seperate building
with all air conditioners provided & we are able to operate the plant with very high uptime
with very minimum breakdowns.
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Best Practice No. 22
Waste Out Of Wealth
Unit:
ITC, Limited
Background:
ITC as a part of their Corporate Social Responsibility Charter has taken up “Wealth
Out of Waste (WOW) as a green initiative to protect environment and reduce global
warming. The effort is to create awareness among general public on the need for waste
avoidance, source segregation maximum recycling, minimizing landfill, to help improve
the environment and work towards a cleaner and greener societies. Against this backdrop, many schools, Corporate, residential locations, commercial complexes were been
approached in Hyderabad and the response, according to ITC, is quite encouraging.
Wow has been designed to manage waste from individual households as well as civic
bodies. It discourages recyclable waste from going into landfills or getting burnt—both of
which damage the environment.
As a part of this programme awareness programme is being conducted to school
children and public on the benefits of the “Reduce-Reuse-Recycle” process.
being encouraged to segregate recyclable waste.
Public is
The WOW initiative has been acclaimed by Municipal Authorities, Environmental Agencies and other as a unique effort with multiple benefits to society. Apart from preserving
and protecting the environment, improving civic amenities, as well as public health and
hygiene, it also generates sustainable raw material for paper and other industries at
competitive prices, there by helping conserve scarce environmental resources.
As against 60-70 % of the waste being recycled in the West (the US and Europe),
only 14 % gets recycled in India. Even China and other Asian countries are better placed,
with 25-30 % recycling.
ITC is actively promoting the WOW (Wealth out of Waste) initiative in Hyderabad,
Bangalore, Chennai and Coimbatore to help increase the recovery of waste paper. The
company provides special bags to accumulate dry wastes such as paper, plastic and
metals and arranges periodic collection through outsourced agencies. The segregated
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dry waste can save almost 40 per cent of municipal garbage handling costs, he pointed
out.
Environmental hazards:
Roughly, 60 per cent of the waste generated in households consists of paper and the
rest, metal, plastics and other things. ITC has been trying to educate the public about the
two-bin system – segregation of waste into two categories (recyclable and the rest) at
source. We are implementing the programme in some of the cities and towns in Andhra
Pradesh. The response has been very good. Recycling of one tonne of waste paper saves
17 trees and 7,000 gallons of water. This is just an example of the benefits of recycling.
Generated quantity:
Every day about 4,200 tonnes of waste were being generated in Hyderabad, of which
1,200 tonnes could be recycled. Mumbai was generating 6,800 tonnes (2,000 tonnes);
Kolkata 5,500 tonnes (1,600); Chennai 4,500 tonnes (1,300); New Delhi 6,000 tonnes
(1,800) and Bangalore 4,000 tonnes (1,200).
Recyclable waste is collected from each house hold by paying Rs.5/- each kg of
waste. ITC - PSPD Company is set to increase waste paper collection for paper board
mills.
Wealth from waste
To focus on spreading awareness in schools
Has tied up with 100 cos to procure waste paper
ITC has decided to step up its waste paper collection business under its WOW (Wealth
out of Waste) programme, to augment raw material supply for its paper board mills. ITC
uses about 1.8 lakh tonnes of imported waste paper annually at its mills in Coimbatore
and Bhadrachalam. The company needs about 3 lakh tonnes of waste paper annually.
The balance is sourced domestically.
Achievements:
The total wastepaper collected though this programme amounted to 6000 tonnes during
2008-09.
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Total Waste paper recycled for operations is 40,194 tonnes during 2008-09.
Creation of employment opportunities and a heightened spirit of civic responsibility.
Achieved collection of 2700MT in the month of June’09.
Wealth Out of Waste would be a source of procurement of material to the company by
recycling the existing wastepaper within the communities and keeping the environment
clean and green and also making societies zero waste societies. Wealth Out of Waste aims
at sustainability of the economy by contributing to the nature as well as to the countries
development.
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Best Energy Practice: 23
Particulate Emission Reduction Through Enhanced ESP Efficacy Scheme In High
Pressure Chemical Recovery Cogen
Unit: Seshasayee Paper And Boards Ltd
Background:
A high pressure chemical recovery boiler is in operation. The main steam parameters
are maintained at 65 kg/cm2(g) and 460oC.
The chemical recovery boiler has an Electrostatic precipitator with the state of the art
technology engineered and supplied by BHEL. The ESP is designed with 4 fields in single
pass. The single pass ESP is chosen to meet the present operating load of 630 TPD BLS
(dry) firing in recovery boiler. It shall add one more pass at a later stage when the rated
capacity of the boiler is increased .
As per the state pollution control board norm it is just sufficient to maintain SPM level
at 150 mg/Nm3(dry). However, with additional field the ESP has been designed to maintain the SPM level of 50 mg/Nm3.
Because of the space constraint, adequate straight ducting and a central uniform flue
gas entry could not be ensured. The flue gas entry is from the bottom of the ESP. Hence,
the gas scewing could not be avoided even with the gas distribution screen in place. Even
providing a deflector plate and plugging of few holes in the entry screen for uniform gas
distribution could not ensure the desired SPM emission when the load is higher.
Objective:
To achieve SPM content in flue gas leaving stack at 50 mg/Nm3.
Process:
After a detailed study and series of adjustments for uniform gas distribution it was
identified that there is a need for removal of ash from the last field of the ESP for minimising
the SPM emission level. For faster removal for ash from the last field, rapping mechanism
was installed.
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The rapping mechanism ensured faster removal of ash from the field and hence
improved collection efficiency in the last field. This has resulted in reduction in SPM emission level below 50 mg/Nm3.
View of Boiler 11 –Chemical Recovery Boiler -4 field ESP with inlet & outlet ducts
Benefits:
The SPM emission is reduced to the level 50 mg/Nm3. This requires only a marginal
investment for installing the rapping mechanism in the last field of the ESP.
Issues:
None reported.
Replication:
This concept can be comfortably replicated in other pulp mills having Recovery Boiler
aiming for low SPM emission. As a matter of fact, TNPL had adopted in a small way, the
deflector concept at ESP gas entry, for effecting reduction in SPM in flue gas leaving ESP
(of FLS design).
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Best Energy Practice: 24
Water Conservation In Vacuum Pump By Reusing Culvert Water Through Save-All
Unit: Seshasayee Paper And Boards Ltd
Background:
Paper Machine 5 [PM5] is consuming significant amount of fresh water for the
Vacuum pumps due to fines contamination and high temperature of return culvert
water.(Fig.1). As cooling tower fins also got chocked with fines, it leads to frequent poor
performance of cooling tower.
The vacuum pump cooling tower kept overflow by adding fresh water to reduce
temperature and contamination of fines. This overflow was sent as effluent to ETP.
Objective
Reduce fresh water addition in vacuum pump cooling tower to lower temperature and also saving in fibre, all wet end chemicals and fines which is required for better
formation of sheet.
Details Of Best Practice Initiated
The Vacuum pumps required around 2400 m3/day. It required 300 m3/day fresh
water addition to reduce the temperature of cuvert water from 50oC to 40oC even though
the same was passed through cooling tower.
It was decided to reduce the fines content in return water thus to make the water
useful for better performance of cooling tower. As we had additional capacity of Poly Disc
save all capacity, the culvert water was diverted to save all and clear water from back
water was taken to vacuum pump for sealing.
Thus Vacuum sealing water temperature also got reduced to 40oC without additon of
any fresh water ( Fig.2).
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Vacuum Pump cooling tower makeup water was replaced with Clear Filtrate Water (60
ppm) from Poly disc save-all to replace Fresh water Make up.
Vacuum sump water was diverted to Poly Disc Save-all and the excess clear water of
60 ppm from White water tower was supplied to Pulp mill for Bleached Tower Pump
Consistency control.
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Benefits:
By Process modifications and using the available automation, the following benefits are
being realised :
Fresh water (340 m3/day) is replaced with Clear filtrate from Save-all.(Fig.3)
Cooling tower fins are not getting chocked with fines.
Back water is used in Pulp mill helps to maintain final pulp Brightness (Since Back water
contains OBA)
ETP load is reduced.
Costly fibres and fillers are recovered from Vacuum pump sealing water, thus disturbance
in wet end chemistry like Charge Demand, etc are avoided.
By closing the water loop in the Paper Machine complex, wet end chemical consumption
is optimized.
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Issues:
None, as of date.
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Best Practice No. 25
Water and waste water Management Initiatives at TNPL
Unit: TNPL
Water Management initiatives
The approach followed at TNPL to reduce water consumption is as follows.
Measure water consumption
Analyze requirement at individual sections
Fix targets (short term & long term)
Identify and Implement water conservation schemes
Monitor the benefits
Revise goals/targets
Different streams of water have been analyzed for possibilities of recycling after some
treatment. The following table gives some of the streams of return water being matched
with the recycling opportunity.
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ACTION PLAN & CONCLUSION
Action Plan
The individual paper plants have to assess the present performance and should
develop its own individual target for improving parameters concerning energy, water
and environmental performance
Set and achieve voluntary target of at least 1 to 5% reduction in specific energy
consumption every year
The best practices and the performance improvement projects compiled in this manual
may be considered for implementation after suitably fine tuning to match the individual
plant requirements
If required, CII-Godrej GBC will help the individual units to improve the performance
by providing energy audit services and identifying performance improvement projects
specific to individual units to achieve the targets
The present level of performance and the improvements made by the individual
units have to be monitored
The performance improvement of these units will be reviewed in the “Papertech”
every year and the information will be disseminated among the Indian Pulp and
Paper plant
Conclusion
The objective of the project will be fulfilled only if the performance of all the pulp and
paper units improves and achieves world class standards.
We are sure that the Indian Pulp and Paper units will make use of this opportunity,
improve their performance and move towards the world class Energy Efficiency.
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ANNEXURE
LIST OF WORKING GROUP MEMBERS
S.No
Name
Designation
Company
1
Mr K M Kassetty
General Manager (Paper)
APPM
2
Mr. Siva Prasad
3
Mr. P V Raman
Manager - Recovery
APPM
4
Mr. Mahesh Puranam
Engineer - Energy
CII-Godrej GBC
5
Mr. S Karthikeyan
Counsellor
CII-Godrej GBC
6
Mr. D Ravinder Reddy
Counsellor
CII-Godrej GBC
7
Mr. K Sivaram
Counsellor
CII-Godrej GBC
8
Mr. M B S Nair
President
Emami Paper Mills Ltd
9
Mr.N.Thirugnanam
Manager(Paper)
Emami Paper Mills Ltd
10
Mr. S K Jain
Vice President
Emami Paper Mills Ltd
11
Mr. A Das
General Manager
ITC Ltd
12
Mr A Padmanaban
General Manager
ITC Ltd
13
Mr. DV Satish. Babu
ITC Ltd
14
Mr. G Madhusudan Rao
ITC Ltd
15
Mr. G. Manikanta
ITC Ltd
16
Mr. Siva Prasad
17
Mr. Srikrishna
18
Mr. B Pandey
19
Mr. Jayant Dunakhe
20
Dr. Marimuthu
AGM ( R&D)
SPB
21
Dr. T G Sunderraman
Head (Energy)
SPB
22
Mr. Bharathi
[Paper Machine ]
SPB
23
Mr. Mhd. Khalibullah
[Project]
SPB
24
Mr. Sridhar
[Fiberline]
SPB
25
Mr. Asokan
Manager - Pulp
TNPL
26
Mr. K.Kuppuswamy
DGM (Pulp & Recovery)
TNPL
27
Mr. Ranjith
28
Mr. D Ravichandran
Asst Manager - Paper machine
TNPL
29
Mr. T Venugopal
Manager - Sales
Vacon Drives
APPM
Chief Engineer
ITC Ltd
ITC Ltd
General Manager
JKPM
Siemens
TNPL
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