Demin Data NSPECS .qxd - Eco-Tec

PB0104BNS
RECOFLO WATER DEMINERALIZER
®
Do more with less . . .
he Recoflo Demineralizer is much
more than just another packed-bed,
counter-current ion exchange system.
The distinctive design and operating
features of the Recoflo Demineralizer
allow for the production of higher purity
water at lower operating and total
installed costs.
The high ion exchange efficiency of
the Recoflo Demineralizer results in a
reduction in chemical usage and waste
generation, and allows for the production of high purity water (conductivity as
low as 0.1 µS/cm) without the need of a
mixed bed polisher. The shorter cycles
make the Recoflo Demineralizer more
resistant to organic fouling and allow for
the more effective removal of colliodal
and ionic silica.
Shallow resin beds (6 in/15cm) and a
small resin volume reduce resin
replacement expenses. The compact,
T
RECOFLO®
WATER
DEMINERALIZER
Low installed cost,
low operating cost,
and small space
requirement
skid-mounted design requires less floor
space and headroom than other demineralizers and no elaborate civil work is
required for installation. To further
reduce the cost of commissioning and
installation, the resin is pre-loaded and
the unit is fully tested with regenerants
prior to shipment.
Low operating costs, high performance and proven reliability make the
Recoflo Demineralizer the choice of
industry leading companies worldwide
including PacifiCorp, Dynegy Midwest
Generation and Borden Chemicals &
Plastics in the United States; Ontario
Power Generation, TransAlta Energy,
Dupont Canada and Delta Hudson in
Canada; Kiwi Dairy in New Zealand and
United Phosphorus in India.
Recoflo ion exchange features...
Short bed height/small resin volume - The resin beds in the Recoflo
Demineralizer are only 6 inches (15 cm)
in depth and have approximately 10% of
the resin volume of other demineralizers
(Figure 1). A shallow bed is made possible by the rapid ion exchange kinetics
that result from the use of fine mesh
resins and low resin loading.
1
Loaded resin
Fine mesh resin - Since exchange
kinetics and regeneration efficiency is
improved by using only the exchange
sites at surface of the resin beads, a fine
mesh resin is used to increase the total
surface area that is available for
exchange. The size of these resin beads
is approximately one quarter the size of
the resin used in other demineralizers
(Figure 2). This resin is uniformally sized
to maximize the efficency of rinsing and
promote uniform distribution of flow
through the bed.
3
Reaction zone
Unused resin
Figure 1
Figure 2
Low resin loading - Unlike other
demineralizers that load the resin to
near exhaustion, the Recoflo demineralizer uses less than 20% of the total
exchange capacity of the resin. By
using only the most accessable
exchange sites at the surface of the
resin beads, the exchange kinetics are
improved and regenerant usage is
reduced since the sites that most readily accept an ion are those most easily
regenerated. In addition, the low resin
loading does not force the resin to
undergo large changes in size that
cause resin fragmentation in other demineralizers.
2
Higher throughput rates - The
rapid ion exchange kinetics and short
resin beds allow for high throughput
rates, typically 3 to 5 times higher than
other demineralizers. The high flowrates
result in a smaller resin bed diameter
and hence a reduction in the required
amount of floor space.
4
Recoflo ion exchange features...
Counter-current regeneration - To maintain
the cleanest resin at the bottom of the resin
beds after regeneration, the regenerant is
passed through the bed in the opposite direction
of the feed flow (Figure 3). Counter-current
regeneration minimizes regenerant usage and
maximizes product water quality.
5
Packed resin beds maximize regeneration efficency by maintaining the exchange zone profile
and ensuring proper flow distribution through the
bed. Eliminating the freeboard reduces rinse
requirements by minimizing intermixing and liquid dilution.
BEFORE REGENERATION
FEED WATER
▼
▼
▼
Figure 4
PRODUCT WATER
AFTER REGENERATION
WASTE
▲
▲
REGENERANT
6
RESIN
Figure 3
Compressed resin beds - The resin beds in
the Recoflo Demineralizer are fully packed
such that no freeboard exists. In fact, the resin
beds are compressed by adding an excess of
resin prior to closing the vessel (Figure 4).
Shorter cycle times - The combination of
high flowrates, low resin loading and small
resin beds result in short cycle times, both in service and regeneration. Whereas other demineralizers are onstream for approximately 20 hours
and require several hours to regenerate, the
Recoflo Demineralizer is typically onstream for
less than 30 minutes and is regenerated in less
than 7 minutes. The shorter cycles allow for the
continuous supply of the required flow with only
one unit since during the short regeneration period, water can be drawn from the product storage
tank. This buffer volume and the demineralized
water used for regeneration is then replaced during the subsequent onstream cycle. The shorter
cycles also facilitate troubleshooting since many
cycles can be witnessed in a single shift after the
remedial action has been performed.
7
Recoflo Demineralizer Cycle...
1. Onstream
5. Internal Recirculation (0.30 minutes)
Filtered feedwater
CATION
ANION
Deionized water
Pre-filtered water
is pumped downward through the
resin beds. The
length of the
onstream time
depends upon
the feed total dissolved solids
concentration
and desired product water quality.
2. Anion Pre-Heat (0.50 minutes)
Waste
ANION
CATION
Warm deionized water
ANION
CATION
6. Cation Regeneration (0.13 minutes)
To maximize the
efficiency of
removing silica
from the anion
resin during
regeneration, the
cold anion bed is
heated with
warm demineralized water from
the warm water
supply system.
Waste
ANION
CATION
Acid
Deionized water
3. Anion Regeneration (0.44 minutes)
Waste
ANION
CATION
Caustic soda
Warm deionized water
Concentrated
caustic drawn
from the bulk
supply is diluted
in-line immediately below the
anion bed with
heated demineralized water from
the product storage tank. The
diluted caustic is
pumped upward
through the anion
bed.
CATION
Deionized water
ANION
The anion bed is
rinsed with demineralized water
from the product
storage tank to
wash out remaining caustic
regenerant.
Concentrated
acid drawn
from the bulk
supply is diluted in-line
immediately
below the
cation bed with
demineralized
water from
storage tank.
Diluted acid is
pumped
upward
through the
cation bed.
7. Cation Rinse (0.37 minutes)
Waste
ANION
CATION
Deionized water
The cation bed
is rinsed with
demineralized
water from the
product storage tank to
wash out
remaining acid
regenerant.
8. Internal Recirculation
4. Anion Rinse (2.49 minutes)
Waste
Water within
the system is
circulated in a
closed loop
through the
resin beds to
move trace
sodium ions
from the caustic regenerant
to the cation
bed.
CATION
ANION
Prior to
onstream,
water at the
outlet is purified to desired
quality by circulating water
within the system in a
closed loop
through the
resin beds.
Length of time
for this step
depends upon
the desired
product water
quality.
Benefits ...
PRODUCT CONDUCTIVITY
(µmhos/cm)
SYSTEM PERFORMANCE
Produce High-Purity Water Without a
Mixed-Bed . . .
0. 5
0. 4
0. 3
0. 2
0. 1
0
0
5
10
15
20
25
30
DAY
Figure 5
SILICA LEAKAGE
1100
0
PRODUCT SILICA
(ppb)
9
90
8
80
7
70
In
many
cases,
the
Recoflo
Demineralizer is able to produce water
with a conductivity as low as 0.1 µS/cm
(10 megohm.cm resistivity) with less
than 0.010 mg/L of silica using only the
cation and anion beds (Figures 5 & 6).
This high level of performance is made
possible by the rapid and efficient
exchange kinetics resulting from the use
of fine mesh resins and low resin loading. The elimination of the need of a
complicated mixed bed reduces space
and labour requirements and removes
any risk of resin cross contamination due
to imperfect separation or re-mixing of
resins during regeneration.
6
60
50
5
Reduce
Commissioning
Installation Costs . . .
4
40
3
30
20
2
10
1
00
00
5
10
15
20
25
30
DAY
Figure 6
and
Prior to shipment, the Recoflo
Demineralizer is completely assembled
and wired, and the resin is loaded into
the beds. To reduce the time required
for commissioning, the Recoflo unit is
fully tested at the factory. Flowrates are
adjusted, valve sequencing is checked,
the operating program is debugged and
the specified water quality is produced
using regenerant chemicals. This significantly reduces commissioning time
while providing an opportunity for handson operator training at Eco-Tec. A
Recoflo Demineralizer can be commissioned in 2 to 3 days as compared to 2
to 4 weeks for other packed bed sys-
Benefits ...
tems. Once on site, the compact, skidmounted design allows for easy placement and installation with no elaborate
civil work.
In addition, there is no need for regenerant
dilution systems or separate feed pump
skids as required with other demineralization systems. Each individual Recoflo
Demineralizer skid contains the acid and
caustic injection pumps and a multi-purpose centrifugal pump that is used to
pump the feed water, dilution water, rinse
water and the water during the recirculation steps.
Reduce Space . . .
The high throughput rate of the Recoflo
Demineralizer is 3 to 5 times that of other
Demineralizers. This increased productivity, and the shorter resin bed, result in a
much smaller vessel diameter and low
headroom requirements. In addition, the
shorter cycle times reduce the size of the
auxiliary equipment (e.g., waste neutralization, warm water supply) since small
volumes of waste will be generated
throughout the day rather than a large
volume of waste being produced daily.
The Recoflo Demineralizer requires
approximately one half of the floorspace
and headroom of other demineralizers.
Reduce Operating Costs . . .
The Recoflo Demineralizer offers substantial savings in operating costs. The
distinctive design and operational features of the Recoflo ion exchange
process guarantee the lowest consumptions of the acid and caustic. The lower
regenerant usage and highly effective
rinsing of the resin result in the efficient
usage of water and the subsequent minimization in waste generation (Figure 7).
The small resin volume, approximately
10% of other demineralizers, allows for
the inexpensive, simple and expeditious
replacement of resin.
Figure 7
CONVENTIONAL
RECOFLO®
34,500
gallons
(130 m3)
152
gallons
(0.57 m3)
128
gallons
(0.48 m3)
DAILY
WASTE
FLOW
DAILY
CAUSTIC
USAGE
DAILY
ACID
USAGE
20,500
gallons
(77 m3)
96
gallons
(0.36 m3)
67
gallons
(0.25 m3)
Benefits ...
Reduce Operator Attention . . .
The fully automated Recoflo system is PLC controlled
with many self-diagnostic features. The key operating
parameters can be made available for monitoring and
trending from a remote location via the internet or a
plant's DCS system and locally on a Human Machine
Interface screen (Figure 8). The low operator requirements of the Recoflo unit has made it the ideal system
for low or unstaffed locations such as the Tilton and
Freedom power peaking stations (Figure 9).
Rapid Return to Service . . .
Human Machine Interface (HMI) Screen
The Recoflo demineralizer can be returned to service
after a single 7 minute regeneration cycle, regardless
of how long the system has been on stand-by. The
return to service can be automatically triggered by a
low-level signal. Other demineralizers require a 3 to 4
hour regeneration cycle and rinse-down, with a substantial amount of waste water being generated. This
feature makes the Recoflo System ideal for applications involving intermittent operation such as in power
peaking stations or for the batch production of pharmaceuticals.
Tilton Energy Center, Danville, Illinois
Figure 9
Figure 8
Feed Forward Control . . .
The conductivity of surface water that feeds the demineralization system can vary seasonally. The Recoflo
System can include a feed forward conductivity controller that will automatically adjust the operating parameters of the demineralization units to account for
changes in the feed total dissolved solids concentration. This ensures the resin beds are always regenerated with the correct volume of regenerant, while also
optimizing chemical consumption.
Removal of Colloidal Silica . . .
Unlike other packed-bed demineralizers, the Recoflo
Demineralizer has shown to be very effective at
removing colloidal silica. The high surface area of the
fine mesh anion resin provides attachment sites for
the negatively charged colloidal silica particles. The
short onstream time ensures that the
Recoflo Demineralizer is taken out of service for regeneration before the exchange
sites at the surface of the resin are exhausted and breakthrough of colloidal silica
occurs. Field data from several sites
employing the Recoflo Demineralizer for
purification of well and surface waters have
shown a reduction in colloidal silica concentration from up to 2.5 ppm to less than 0.010
ppm.
Benefits ...
Resistance to Organic Fouling . . .
RECOFLO® EXPERIENCE WITH ORGANICS
Ottawa River at the
Ottawa Heath Science Centre
Cogeneration Facility
Canada
feed TOC = 2.5 mg/L
effluent = < 180 ppb
Narmada River at the
Search Chem Cogeneration Plant
India
feed TOC = 4.2 mg/L
effluent = < 200 ppb
ECO-SERV Service Program . . .
The Recoflo Demineralizer is fully covered
under Eco-Tec's ECO-SERV Customer
Service Program. The program begins
with strict quality assurance at every stage
of the design and manufacturing processes, as demanded by ISO 9001. Samples
of resin from every shipment are tested inhouse to confirm the particle size distributions and ion exchange characteristics.
The filter vessels and piping systems are
constructed in accordance with ASME
guidelines. Prior to shipment, the demineralizer is tested with regenerant
chemical to produce the specified
water quality. An Eco-Tec Customer
Service Representative can be onsite to provide supervision during
start-up and to offer operator training.
A Service Representative is available 24/7
to assist with any aspect of the system.
Naturally occurring organics, such as humic and fulvic
acids, enter into feed water supplies from decaying
vegetation. These large organic molecules are negatively charged and are exchanged onto the anion
resin. The long onstream cycle time of deep-bed
demineralizers give the organic molecules ample time
to penetrate deep into the resin bead. Once entangled
within the resin bead matrix, the organic molecules are
not effectively removed by regeneration. Organic fouling will cause a reduction in demineralizer performance, efficiency and capacity.
The operation of the Recoflo Demineralizer makes it
more resistant to organic fouling. The short cycles
promote the frequent removal of organics and prevent
them from penetrating into resin bead structure.
ECO-TEC INC.
ECO-TEC (Europe) Ltd.
Units 5C, D & E, Chase Park Industrial Estate, Ring Road, Burntwood,
1145 Squires Beach Road, Pickering,
Staffordshire, England WS7 8JQ
Ontario,Canada L1W 3T9
Telephone: 44-15436-83086 Fax: 44-15436-74117
Telephone: 905-427-0077 Fax: 905-427-4477
email: [email protected]
email: [email protected]
www.eco-tec.com
The information contained in this document is proprietary and is the sole property of Eco-Tec Inc., no part may be reproduced without the express consent of Eco-Tec Inc.