Energy Efficient Technology Packages

Transcription

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PREFACE
United Natio ns Deve lopment Progr amme (UNDP) in collaborat ion wit h
Ministry of Steel (MoS), Gover nment of India ( GoI) with funding s uppor t
from Global Env ironmental Facil ity ( GEF) implement ed a pro ject t itle d
“Removal of Barriers to Ener gy Effic ie ncy Improvement in the Ste el R e Rolling M ill S ector in India” b etween 20 04 an d 2013. Th e pro ject ide ntif ie d
energy eff icie nt techno logy packages fo r reheatin g furnac e a nd roll ing mil ls .
The project provide d techn ical ass istan ce and f ina ncial incent ive to th e
SRRM un its to adopt en ergy ef fic iency measures. 34 stee l rerol ling m ill s
have successf ully ado pted ener gy effic ie nt technologies an d accomplish ed a
substantial savin gs in sp ecif ic ener gy consumption an d reduction in GHG
emissions . Ener gy savin gs were a pprox imately 25% in f urnace o il us in g un it s
and excee de d 40% in coa l us in g units .
UNDP alon g with MoS and supporte d by AusAID, has l aunch ed a n ew project
to upscal e the en ergy eff iciency meas ures in stee l reroll in g an d other
subsectors. The project titl ed “Upscal ing En ergy E ffic ient Production in
Small Scale St eel I ndustry in India” aims at
 Up-scal ing Ener gy Effic ie ncy int ervent ion s in abo ut 300 S R RM
 Piloting E E measur es in other ste el s ubsectors such as I nduction
furnaces
 Tria lin g seco nd gen eration of technolo gy packages in SRRM
This publ icat ion provides description of dif ferent technolo gy packa ges ,
salie nt feat ures an d economic ben efits . Most o f these are successf ull y
demonstrated in the earl ier project . The aim of th is p ubl icat ion is to
disseminate details of vario us tech nology packa ges among the SRRMs sector
and to help to them to suitably choose the appropr iate techno logy to improv e
their pr esent ener gy consumpt ions an d re duce associat ed GHG emiss ions . W e
hope the units w il l find th is p ubl icatio n f or them to make informed cho ice.
S N Srin ivas
Programme Analyst [E nergy for Deve lopment]
United Nat ions Develo pment Progr amme
N o.
1
2
C a t e gor y
GR O UP 1 A
Low -e n d EE
t e ch
e q uipm e nt
GR O UP 1 B
Low -e n d EE
t e chn ol ogy
pa cka ge
3
GR O UP 3
H igh-e nd
t e chn ol ogyDir e ct
r ol l in g
4
GR O UP 5
New
ge n e r at ion
EE
t e chn ol ogie s
E E Te chn ol ogy
Sh ell i n sh ell t y p e recu p erat o r fo r pu lv eri z ed co al
fi ri n g sy st em
Mo d i fi ed pu lv eri z ed co al fi ri n g sy st em
En ergy effi ci en t pu lv eri z o r
I n st allat i o n o f au to mat i on & con t ro l sy st em
(Pro p o rt i on al I n t egrat ed Deri v at i v e [PI D] based fo r
reh eat i n g fu rn ace ai r - fu el rat i o co n t ro l sy st em)
H i gh effi ci en t U - tu be cro ss flo w t y p e met alli c
recu p erat o r (fo r fu rn ace o i l / gas fi red reh eat i ng
fu rn aces)
V ari able V o lt age V ari abl e Frequ en cy (V VV F) dri v e
Un i v ersal sp i n d les & co u p li n gs
A n t i fri ct io n ro ller be ari n gs
I n st allat i o n o f Y - ro ller t ab le i n 3 - H i mi ll st an ds o f
ro lli n g mi lls
I n st allat i o n o f t i lt in g t able fo r 3 - H i mi ll st an d
En ergy effi ci en t d ri v es fo r ro lli n g mi lls
Rep lacemen t o f exi st i n g fu rn ace w it h n ew en ergy
effi ci en t fu rn ace
C o nv ersi o n o f fo ssi l fu el t o C BM based reh eat i ng
fu rn ace
C o nv ersi o n o f fo ssi l fu el t o bio mass based p ro du cer
gas reh eat i n g fu rn ace
Rev amp i n g / mo d ern i sat i on o f pu lv eri sed co al fi red
re- h eat i n g fu rn ace
Rev amp i n g exi st i n g fu rn ace w i th en ergy effi ci en t
t o p fi red re - h eat in g fu rn ace
D i rect ro lli n g
I n v es tm e n t
e s t ima t e
I m pl em e n
t a t ion
pe r iod
Sav i n gs i n
sp eci fi c fu e l
co n su mp t io n
by 5 - 15% .
I N R 3 – 15
lakh s
2 – 3
mo n th s
F in a n cial
in ce n t iv e
C ap i t al su bsi dy
o f 20% on
i n st allat i o n o f
i n d i v idu al
equ i p men t
M a x im um
pe r un it
I N R 2 lakh s
Sav i n gs i n
sp eci fi c p o w er
co n su mp t io n
by 2 - 10 %
INR 1 – 2
cro res
Sav i n gs i n
sp eci fi c fu el
co n su mp t io n
by 20 - 35% .
INR 1.5- 3
crores
Sav i n gs i n
sp eci fi c fu el
co n su mp t io n
by 8 0 - 10 0% .
6 – 8
mo n th s
I N R 1. 5 – 6
cro res
Sav i n gs i n
sp eci fi c fu el
co n su mp t io n
by abo v e 40 %
6 – 8
mo n th s
Regen erat i v e bu rn ers
O xy - fu el co mbu st io n sy st em
S a v in g
pot e n t ia l
4 – 8
mo n th s
C o n su lt an cy
fees
rei mbu rsemen t
o n su ccessfu l
co mmi ssi o n in g
o f i nd i v i du al
p ackages
C o n su lt an cy
fees
rei mbu rsemen t
o n su ccessfu l
co mmi ssi o n in g
C ap i t al su bsi dy
o f 20% on
i n st allat i o n o f
i n d i v idu al
equ i p men t
## - EE t ech no lo gy packages under gro up 2 & 4 and addit io nal t ech no lo gies under gro up 5 are under f inaliz at io n.
I N R 2 lakh s
I N R 5 lakh s
I N R 20
lakh s
1A-1 Shell in shell type recuper ator f or pulveri zed co al firing
system
Descr ipt ion

Recuperators are generally heat exchangers
that use the energy in hot waste flue gases to
preheat combustion air. In recuperators heat flows
steadily through the wall from the heat source (hot
flue gas) to the heat receiver (cold combustion air).
Increase
in
air
pre-heat
temperature
can
significantly reduce specific fuel consumption.
Salien t feature s, Investment & Benefi ts
The following table describes the salient features, application, technological advantages,
limitations and cost benefit of the above technology option:

Salient features



Application
Technological
advantages
Waste heat recovery upto 350 0C with a flue gas temperature of
700 0C can be achieved.
Recuperator designed with optimum surface area
Inner shell is made of stainless steel to withstand high
temperature.
All pulverized coal fired reheating furnace, which is not
equipped with recuperator.

This type of recuperator is ideal for pulverized coal fire reheating furnace as conjunction due to coal deposits in the
recuperator line is avoided.

Combustion air temperature to be maintained below 400 0C for
pulverised coal as the same may get ignited.
To avoid heat losses in line, combustion air pipes should be
insulated.
Technological
limitations

Estimated investment

INR 3 – 6 lakhs (depending on the furnace capacity)
Estimated
implementation
period

2 – 3 months.
Expected benefits


Savings in specific fuel consumption by 10 - 15%
Reduction in CO2 emission by 10 -15 %.
Estimated payback on

investment
Less than 6 months.
1A-2 Modified pulver ized co al firing system
Descr ipt ion

The steel rerolling units to a large
extent uses coal as fuel for the reheating
furnaces. However the obsolete design of
the pulverized coal firing system leads to
incomplete combustion, thereby leading to
higher specific thermal energy consumption
and burning loss.

The modified pulverized coal system provides a solution towards eradicating un-
burnt coal particles, there by leading to lower specific fuel consumption.

Separate hoppers with silo and air filter system placed above
burners.
Specially designed burners allow use of hot preheated
combustion air and also proper mixing of fuel and air.
Air fuel flow controlled through automatic control system.


Salient features

Application
Technological
advantages


The system provides solution for using 100 % hot combustion
air.
Control flow air & fuel leads to lesser fuel consumption.

Preheated combustion air above 400 0C may lead to ignition of
the pulverized coal.
Moisture content in coal may lead to coal deposits in hoper.

INR 5 – 15 lakhs (excluding recuperator)
Estimated
implementation
period

2 – 3 months.
Expected benefits


Savings in specific fuel consumption by 10 - 15%.
Reduction in CO2 emission by 10 -15 %.
Technological
limitations


investment
Less than 6 months.
1A-3 Energy effici ent pulv erizor
Descr ipt ion

In
order
to
achieve
maximum
combustion efficiency (-) 200 mesh fines of coal
is recommended.
through
a
The same can be achieved
modified
and
energy
efficient
pulverizor design.




High manganese alloy, high carbon and high chromium
hammer with approximately 2000 – 2200 gms weight.
EN31 steel machine grooved liner hardened with nitriding.
Stainless steel classifier blades.
Stainless steel fan blades
RPM of approximately 2200.


Salient features
Application
Technological
advantages


Fines of -200 mesh coal size can be achieved.
Better life of pulverizor.
Technological
limitations

Maintenance of critical part to be more frequent.

INR 10 -15 lakhs.
Estimated
implementation
period

2 – 3 months.
Expected benefits


Savings in specific fuel consumption by 5 – 10%.
Reduction in CO2 emission by 5 - 10 %.

investment
6 – 9 months.
1A-4 Installation of automati on & control system (Propor tional
Integrated Der ivativ e [PID] based for reh eat ing furnace air-fue l
rati o contr ol system)
Description

Control systems with microprocessor based PID controllers
are used in reheating furnace for controlling and regulating airfuel flow which has direct impact on the specific fuel
consumption.
The following table describes the salient features, applications, technological advantages,

Salient features



Application

Control of desired temperature regimes and air-fuel ratio are
possible.
Operator interaction for maintaining temperature is minimal.
All types of re-heating furnace irrespective of type of fuel.
The installation of automation & control system is to monitor
flow of combustion air & gases, temperature, air fuel ratio and
pressure.
Complete interlocking and sequential control of the furnace
with respect to the charging and discharging shall be done
through relay logic to be provided in the instrumentation
panel.
Technological
advantages



Optimum fuel flow, air flow and excess air % are maintained.
Automatic control based on operating scenario.
Human errors are minimized.
Technological
limitations


Skilled manpower requirement.
Maintenance of system and instruments are required.

INR 5 -10 lakhs.
Implementation
period

2 -3 months.
Expected benefits


Savings in specific fuel consumption by about 5 - 10%.
Reduction in CO2 emissions by 5 – 10 %.
investment

Less than 6 months.
1A-5 High effici ent U-tube cr oss flow type metalli c recuper ator (fo r
furnace oil / gas fired rehe ating furn aces)
Descr ipt ion

Recuperators
are
generally
heat
exchangers that use the energy in hot waste flue
gases to preheat combustion air. In recuperators
heat flows steadily through the wall from the
heat source (hot flue gas) to the heat receiver (cold combustion air). Increase in air pre-heat
temperature can significantly reduce specific fuel consumption.

Salient features



Any reheating furnace (with F.O /gas fired), which is not
equipped with a recuperator or existing recuperator operating
with low performance (with recuperator efficiency less than
30% or temperature at recuperator outlet less than 200 0C).


High pre-heat temperature for combustion air is achieved.
Better combustion.

Application
Technological
advantages
Waste heat recovery as high as 80% of the flue gas temperature
can be achieved.
Recuperator designed with optimum surface area
Stainless steel tubes in 1st pass and boiler quality steel in second
pass.
Technological
limitations

When the flue temperature is high, dilution with air is
required.
With the use of high temperature recuperator, the combustion
air pipes of burner need to be insulated when air temperature
is more than 400 0C.

INR 5 – 20 lakhs (depending on the furnace capacity)
Implementation
Period

2 – 3 months.
Expected benefits


Savings in specific fuel consumption by 5 - 10%.

investment
Less than 6 months.
1A-6 Variable Vol tage Var iable Freq u ency (VVVF) drive
Descr ipt ion

It is a type of adjustable-speed drive used in
electro-mechanical drive systems to control AC
motor speed and torque by varying motor input
frequency and voltage.
Salient features

Can be added to existing motors & drives.
Application



Reheating furnace blower
TMT pumps
Rolling mill auxiliary motors

Energy losses are quite high in case of electrical equipment
running at fixed speed. Thus for optimum utilisation of power,
VVVF drives are most appropriate which delivers required
output for loads of varying type.
Fast and accurate control of torque and speed of drives under
all operating conditions leading to savings in electric power
consumption.
Technological
advantages

Technological
limitations

Trained operating personnel with some electrical knowledge.

Upto INR 5 lakhs.
Implementation
period

2 – 3 months.
Expected benefits


Savings in specific power consumption by 2- 3 %.

investment
Less than 6 months.
1A-7 Universal spindles & couplings
Descr ipt ion

In rolling mills, spindles & couplings are used
for transmitting power to the rolls from mill
drives/motors.

Universal joint defines as mechanical device
that can transmit torque and rotational motion from
one shaft to another at fixed or varying angle of
intersection of shaft axes.
Salient features
Application
Technological
advantages


Has high torque carrying capacity.
Easy to connect or disconnect the coupling.

Any rolling mill with provision of changing over from CI
wobbler.

It allows some misalignment between the two adjacent shaft
rotation axes.
Operates with negligible back lash and radial clearance to
improve productivity.
Reduced maintenance.




Inter-stand distance is constraint.
Improper design of coupling & spindle can lead to vibration and
significant transmission loss.

The cost of eight sets of universal coupling and spindle for
460 mm four stand roughing mill train will be approximately
INR 10 -15 lakhs.
Implementation
period

2 – 3 months.
Expected benefits


Savings in specific power consumption by 5 – 8%.
Reduction in CO2 emissions by 5 – 10%.
Estimated payback
on investment

Less than 1 year.
Technological
limitations
Estimated
investment
1A-8 Antifri cti on roller bearings
Descr ipt io n

Basic purpose of bearing in rolling mills is
to provide a frictionless support and guide a
rotating machine part.

Antifriction
roller
bearings
are
more
desirable than fibre/brass cotter bearing due to
their lower friction and reduced lubrication requirement and their coefficient of friction is
0.005.
Salient features
Application
Technological
advantages
Technological
limitations



Less friction due to facet contact.
Better tolerance of products.
Longer life and can be fitted in existing system with
modification.

All mill stands excluding the ones having layout/technological
constraints.

An antifriction bearing minimizes torque on spindle leading to
lower power consumption.
Higher mill speed can be achieved with respect to other
bearings.


Modification in roll chock design.

Approximately INR 3 – 6 lakhs to cater to 460 mm 3 Hi roughing
mill stand.
Implementation
period

2 – 3 months.
Expected benefits



The mill utilization goes up by 5%.
Savings in specific power consumption by 3 – 5 %.
Reduction in CO2 emissions by 3- 5%.
Estimated payback
on investment

Less than 1 year.
Estimated
investment
1A-9 Installation of Y-roll er t able in 3-Hi mill st ands of rolling
mills
Descr ipt ion

In three-high (3-Hi) mill, three rolls rotate in one
direction and the metal is fed through two rolls and then
returned through the other pair with middle roll being
common.

Material handling in typical 3 Hi mill train is done manually. A Y-roller table is a
steel fabricated material handling system for automatic transfer of bar from one stand to
another stand.

Roller is skewed for bar to be taken up by Y roller table and feeds the bar between
top roll and middle roll of 3-Hi mill. It improves bar handling, less temperature drop for
next pass and human safety.

Designed based on production handling capacity for automatic
transfer of hot bar
Application

3 Hi mill train rolling billet less than 130 mm cross section.
Technological
advantages


Elimination of temperature variation of stock
Elimination of human error
Technological
limitations

Mill logistics

Y-roller table mounted at 1st stand of 480 mm roughing mill to
convey the rolling stock, size 1500 mm wide X 14800 mm long is
around INR 5 - 10 lakhs.
Implementation
period

2 – 3 months
Expected benefits




Approximate reduction of 3 -4 skilled manpower per shift.
10 % increase in mill utilization.
Savings in specific power consumption by 4 – 7 %.
Reduction in CO2 emissions by 4 – 7%.
Estimated payback
on investment

Less than 1 year.
Salient features
Estimated
investment
1A-10 Installation of t ilting table f or 3-Hi mill stand
Descr ipt ion

Re-rolling sector in India in general has 3-
hi mill stands in roughing mill train. The metal is
being fed to various passes manually by hooks &
tongs.

Installation of tilting table towards the
entry side and delivery side of passes between
top-roll and middle rolls ensures smooth guided
entry of metal to the passes and also eliminates the
manual lifting, feeding of the rolling stock. This installation further ensures the constant
temperatures for all the various bars.

Designed based on production handling capacity for automatic
transfer of hot bar.

All 3 hi- rough mill stands excluding the ones with layout
constraint.


Elimination of temperature variation
Uniform feeding to passes (lesser damage to front & back ends of
the stock).

Possibility of motor drive failure.

The approximate cost for the installation of tilting table for a 3-Hi
mill stand, 410 mm dia is around INR 10 -12 lakhs.
Implementation
period

2 - 3 months
Expected benefits




Higher Mill utilization by 5 -10%.
Approximately 3-4 skilled manpower is reduced per shift.
Savings in specific power consumption by 6 - 8 %.
Reduction in CO2 emissions by 6 - 8%.
Estimated payback
on investment

Less than 1 year.
Salient features
Application
Technological
advantages
Technological
limitations
Estimated
investment
1A-11 Energy efficient driv es for r o lling
mills
Descr ipt ion

Energy efficient motors are most suitable option
for power intensive steel industries where auxiliary
drives like air blowers, water pumps, oil pumps, compressors etc. are continuously working
for long duration, every day.

Generally in industries, proper sizing of high capacity motors are not practiced,
which draws more power because of low loading or idling operations.

Downsizing such motors and replacing with energy efficient motors will lead to a
considerable savings in power consumptions.
Salient features


High efficiency (upto 92%) – low running cost.
These motors are more tolerant of overload conditions and
phase imbalance.
Applications

All rolling mill auxiliary load motors (upto 315 kW)





High quality and thinner steel laminations on starter.
Corrosion resistant.
Less noise and vibration.
Accurate machine tolerances to reduce fixed losses.
Energy efficient motors in conjunction appropriate capacitor
banks offer an ideal environment for operating the drives at
high efficiency and improved power factor.

The energy efficient motors are especially suitable for
continuously running drives working for long duration
everyday where energy cost is very high.

INR 8 – 10 lakhs
Implementation
period

2 – 3 months.
Expected benefits


Savings in specific power consumption by 4 – 6%.
Reduction in CO2 emissions by 4 - 6%
Estimated
payback
on investment

Less than 1 year.
Technological
advantages
Technological
limitations
1B-1 Replacement of ex isting furnace wit h new energy efficien t
furnace
Descr ipt ion

Energy efficient furnaces are provided
with automatic temperature, pressure control,
high efficiency metallic recuperator and
improved refractory lining.

The heating zone constitutes 70 – 75% of
the total installed heating capacity while the
soaking zone will be having the balance 30 - 25%
heat load.

Top fired pusher type furnace design
with hearth productivity ≥ 300 kg/m2/h.
Salient features







Optimum design of furnace.
Shorter pre-heating zone.
70% of total heat input in heating zone and 30% in soaking zone.
Better combustion system & burners
Optimum refractories & insulation
Waste heat recovery through recuperator
Automation & control system installed.
Application

Across all furnace capacity & fuel types.
Technological
advantages





Uniform heating of stock is achieved
Optimum hearth utilization.
Proper combustion.
Air-fuel ration controlled with optimum sp. energy consumption.
Higher efficiency of furnace achieved.
Technological
limitations


Unique design based on fuel type and raw material cross-section.
Higher capital cost.

INR 1.5 – 2 crores (for a capacity of 20 tph; Stock : Billets of 110 x 110
mm size)

4 – 6 months.


In case of furnace oil, the savings in specific fuel consumption by
20 – 25 %.
In case of pulverized coal, the savings in specific fuel consumption by
35 – 40 %.

Less than 1 year.
Estimated
implementation
period
Expected benefits
Estimated payback
on investment

1B-2 Conversion of fossil fuel to CBM based reheat ing furnace
Descr ipt ion

Coal bed methane (CBM) is a form of natural gas extracted
from coal beds.

Can be utilized as a fuel for re-heating furnace.

Required design modification in furnace to be carried out
along with safety precautions.

Salient features




Application
Technological
advantages




Technological
limitations


Estimated
investment
Estimated
implementation
period
Expected
benefits
Estimated
payback
on investment
CBM is a cleaner, safer, more environmentally friendly fuel than
many other energy sources, including conventional natural gas.
Use of CBM requires certain deign modification in the furnace.
Safety precautions have to be ensured.
All other design features of energy efficient furnace to be
incorporated along with switch over of fuel.
CBM consists of over 90% methane and this can be directly used for
combustion in all types of reheating furnace.
Applicable in areas where CBM is available through pipelines.
Calorific value of CBM is approx. 8,500 to 9,000 kcal/kg.
Furnace Efficiency improved because of use of gaseous fuel.
CBM recovery is carried out in few parts of the country and initial
investment in mining, transporting CBM is very high.
Tar produced needs to be completely removed from the gas.
Otherwise, it can choke valves, pipelines, burners etc.
Higher running cost of CBM.

INR 1.5 – 2 crores (for a capacity of 20 tph; Stock : Billets of 110 x 110
mm size)

4 – 6 months.

In case of furnace oil the savings in specific fuel consumption (along
with furnace modification) by: 20 – 25 %.
Reduction in CO2 (thermal) emission by 100 %. (net zero CO2
emission)


Less than 1 year.
1B-3 Conversion o f f ossil fuel to biomass based produ cer gas
rehe ating furnace
Descr ipt ion

Biomass Gasification converts solid biomass into a more
convenient gaseous form. The gas so obtained is called biomass gas,
which is combustible having a calorific value of 1050 to 1200Kcal/
Nm3, with an average composition of :-

 CO
: 20 ± 1%
 CH4 : 3 ± 1%
 H2
: 20 ± 1%
 CO2 : 12 ± 1%
 and rest N2.
Unlike fossil fuels, biomass does not add carbon dioxide to the
atmosphere as it absorbs the same amount of carbon while growing. It is the cheapest, ecofriendly and renewable source of energy.

Salient features
Application
Technological
advantages
Technological
limitations
Estimated
investment
Estimated
implementation
period
Expected
benefits
Estimated
payback
on investment

Biomass gas has calorific value similar to that of producer gas which
is around 1200 kcal/nm3.
Biomass briquettes can be used in existing coal based producer gas
plants with certain design modifications.

Across all furnace capacity & fuel types subject to availability of
biomass briquettes.

Uniform heating of stock due to better flame controllability with
gaseous fuel.
Carbon neutral fuel and hence, zero CO2 emission.


Biomass/ briquettes availability and installation of biomass gas
generation unit.

INR 1.5 – 2 crores (depending upon capacity)

6 - 8 months.

Savings in specific fuel consumption (along with furnace
modification) by 20 – 25 %.
Reduction in CO2 (thermal) emission by 100%. (net zero CO2
emission)


Less than 1 year.
1B-4 Revamping / modernisation o f pulverised coal f ired re-he ating
furnace
Descr ipt ion

Most of the steel re-rolling mill units in India
use pulverized coal as fuel.

However, in general, most of these reheating
furnaces are of obsolete design and are not equipped
with waste heat recovery, automatic temperature and
pressure control, and good insulation lining.

The following areas of the furnace needs to be
revamped for efficient operation




Waste heat recovery system suitable for pulverized coal firing.
Modified pulverized coal firing system to ensure use of hot gas.
Automatic control of air-fuel ration for controlled heating.
Furnace excess air & pressure control through automatic damper and
online oxygen analyser.
 Improved combustion system with specially designed burners.
 Improved pulveriser to provide better mesh size of coal.
 Improved refractory lining.


Separate hopers with silo and air filter system placed above burners.
Specially designed burners allow use of hot preheated combustion air
and also proper mixing of fuel and air.
Air fuel flow controlled through automatic control system.
Improved design of pulveriser installed.
Improved furnace design along with optimum refractories &
insulation.
Salient features



Application

All pulverized coal fired reheating furnace.
Technological
advantages



Uniform stock temperature.
Higher furnace productivity.
Better mixing & combustion of pulverized coal
Technological
limitations


Requirement of trained operating staff.
Higher capital investment.

INR 1 – 1.5 crores (depending upon capacity)

3 - 6 months.
Expected
benefits


Savings in specific fuel consumption by 20 – 25 %.
Reduction in CO2 emission by 20 – 25%.
Estimated
payback
on investment

Less than 1 year.
Estimated
investment
Estimated
implementation
period
1B-5 Revamping existing furnace w ith energy eff ici ent to p fire d
re-h eat ing furnace
Descr ipt ion

In general most of the SRRM’s uses reheating
furnace which are not equipped with good waste heat
recovery system, automatic temperature and pressure
control, heat recovery system and good insulation lining.

The following areas of the furnace needs to be
revamped for efficient operation
 Furnace Design
 Heat Distribution pattern.
 Temperature & pressure control
 Automatic damper with online oxygen analyser
 High efficiency metallic recuperator
 Improved refractory lining



Controls for desired temperature, pressure & air fuel ratio.
Waste heat recovery upto 500 0C with a flue gas temperature of 700 0C will
be achieved.
Online oxygen analyser will indicate the excess air present in the furnace
which in turn will help in reducing scale losses. The excess air will be
controlled through automatic damper.
Improved refractory lining will be provided to reduce radiation losses.
Furnace design based on optimum hearth utilization (≥ 300 kg/ m2/h).
Separate combustion air and fuel pipelines for different zones of furnace.
Application

Re-heating furnaces of all capacities and different fuel options.
Technological
advantages




Uniform stock temperature.
Higher furnace productivity.
Radiation losses from walls and roofs can be minimized.
Higher waste heat recovery.


INR 1 – 1.5 crores (depending upon capacity)

3 - 6 months.


In case of furnace oil the savings in specific fuel consumption by
20 – 25 %.
In case of pulverized coal the savings in specific fuel consumption by
30 – 35 %.
Reduction in CO2 emission by 20 - 30%.

Less than 1 year.



Salient features
Technological
limitations
Estimated
investment
Estimated
implementation
period
Expected benefits
Estimated payback
on investment

3.1 Direct r olling
Descr ipt ion

Direct rolling process is
a technical evolution of hot
charging, where continuous
cast billet is directly pushed to
the rolling mill, without the
need of intermediate process of
reheating.

The
direct
rolling
process can be adopted in composite units by controlling the secondary cooling of the
continuous casting machine by means of Programmable Logic Control (PLC), hydraulic
cutting of billets, high-speed transfers of hot billets, and a canopy covering over the
conveyer belt.
Salien t feature s, Investment & Bene fi ts



Salient features






Induction furnace facility of suitable capacity installed.
High temperature tapping of liquid metal practiced.
Continuous casting machine (preferably with double strand casting)
installed.
High temperature achieved at CCM cooling bed.
Sequence casting to get required capacity of hit billets.
Secondary cooling of CCM controlled.
Hydraulic shear installed to reduce cutting time.
High speed transfer (with canopy cover) of hot billets to rolling mill.
Design modification in roll pass design to handle hot billets.

Direct rolling is applicable to all the composite SRRM units subject to
availability of required capacity of hot charge from continuous
casting machine.
Technological
advantages

The need for a re-heating furnace is eliminated, resulting in a
complete heat saving due to this redundancy.
Technological
limitations


Maintenance of PLC based system.

INR 1.5- 6 crores (depending on whether CCM is installed)

6 – 8 months


Savings in specific fuel consumption by 80 - 100 %.

Less than 1 year.
Application
Estimated
investment
Estimated
implementation
period
Expected
benefits
Estimated
payback
on investment
5.1 Regenerative burners
Descr ipt ion

Regenerative burners use the heat of flue gases to preheat the air and gases going to
the burners thus optimising the heat input at the source itself.

Set of burners used in the entire length of the furnace.

Air preheat temperatures of around 1000 0C are achievable resulting
in exceptionally high thermal efficiency.
Eliminates installation of blowers and pre-heating zone.

All gaseous fired reheating furnaces.



High thermal efficiency can be achieved through pebble bed
regenerators or with honey comb type regenerators.
Uniform heating of the stock as almost flameless combustion takes
place.
Increased production from existing facilities
Reduced emissions of carbon dioxide and carbon monoxide.


Good instrumentation as pre-requisite.
Unclean gas may affect valves and other change over mechanism.

INR 3-6 crores (depending on the no. of burners required)

6 – 8 months


Savings in specific fuel consumption by 35 – 40 %.
Reduction in CO2 emission by 25 - 30%.

Less than 2 years.

Salient features
Application
Technological
advantages
Technological
limitations
Estimated
investment
Estimated
implementation
period
Expected
benefits
Estimated
payback
on investment

5.2 Oxy-fuel combustion system
Descr ipt ion

Oxy fuel burners’ use pure oxygen to substitute completely / part of combustion air
thus reducing the nitrogen component of
combustion air and hence, reducing sensible
heat loss by reduced volume of flue gas.

Also, lean gases can also be used with
oxy-fuel burners and still required temperatures
can be attained.

The mass and volume of the flue gas are reduced by approximately
75%.
Because of the reduced flue gas volume, less heat is lost in the flue
gas.
The nitrogen percentage in flue gas reduced drastically.
Application

All types of re-heating furnace irrespective of type of fuel.
Technological
advantages



Fuel savings.
Lean gases can also be used.
Low flue gas volume leading to lesser sizing of flue outlet and
chimney
Technological
limitations



Provision of oxygen cylinder bank.
Cooling media for burners.
Requirement of proper control mechanism to maintain needed
temperatures.

Approx. INR 3.5 crores (with oxygen plant / cylinders and one set of
burners as spare)

6 – 8 months


Savings in specific fuel consumption by 30 - 35 %.

Less than 2 years.

Salient features
Estimated
investment
Estimated
implementation
period
Expected
benefits
Estimated
payback
on investment

Reference

Study Report to Ascertain Extent of Replication of Energy Efficient Technologies in Steel
Re-rolling Mill Sector in India 2012-2013, prepared by SAIL-CON.

Data gathering report on Eco-Tech Options, updated by RDCIS-SAIL in 2011-2012.
United Nations Development Programme (UNDP)
55 Lodhi Estate
New Delhi, India. Pin Code - 110 003
Tel: 91 11 46532333. Fax: 91 11 24627612
Email: mailto:[email protected]

Energy Efficient Technology Packages

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