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FS1271EN.doc Jul-13
A-Series, Thin-film membrane (TFM*), PES
Maximum
crossflow
gpm (m3/h)
Average
permeate flow
gpd (m3/day)
Duratherm* STD Series
High Temperature Pure Water Elements
Description and Use
The Duratherm* STD Series is specifically designed
to maximize the benefits of continuous high temperature operation as well as hot water sanitization for industries willing to maximize energy
recovery and use hot purified water.
Separation system sanitization protocol is performed via periodic exposure to temperature as
high as 90°C (194°F) at minimum feed pressure to
kill microorganisms by denaturation and coagulation of the proteins chains.
The Duratherm STD are suitable for separation
systems purifying water at temperature up to
70°C (158°F) in low crossflow environment and no
suspended solids.
This Series includes a variety of size 8” and 4” diameters. All element constructions include
Durasan* Cage outer wrap, Polysulfone ATD and
central tube.
Features and benefits
Prevent bio-fouling development
No disposal costs
100% wet testing Quality Assurance
Durable construction
Sanitization on the permeate side
Table 1: Element Specification
1
Testing conditions: 2,000ppm NaCl solution at 225psig (1,550kPa) operating
pressure, (25°C) 77°F, pH7.5 and 15% recovery before any hot water sanitization.
2
Average salt rejection after 24 hours operation. Individual flow rate may vary
+25%/-15%. Final permeate flow rate is subject to variations in the heat treatments. In most cases, the permeate flow rate after heat treatments will stab ilize at 30-50 percent below the nominal flowrate before heat treatment. For a
conservative design, consider a permeate flow reduction of 50%.
Markets
Food / Beverage
BioPharm
Electronics
Chemical
Figure 1: Element Dimensions Diagram (Female)
Maximum
operating
temperature
Maximum
cleaning
temperature
Maximum
sanitization
temperature
500 ppm-hours,
dechlorination
recommended
5,000 ppm-
days,
dechlorination
recommended
Table 2: Dimensions and Weight
1
These elements are dried and bagged before shipping.
2
Internal diameter unless specified OD (outside diameter).
3
The element diameter (dimension C) is designed for optimum performance in
GE pressure vessels. Other pressure vessel dimension and tolerance may result
in excessive bypass and loss of capacity
Table 3: Temperatures
during sanitization should not exceed 40psi
(275kPa) and the crossflow should not incur a
pressure drop greater than 2psi (14kPa) per element. Heating rate to sanitizing temperature and
cool down should not be faster than 5°C (41°F)
per minute. Maximum sanitization temperature is
90°C (194°F).
Loss of permeate flow after repeated
90°C (194°F) sanitization cycles
It is almost impossible to exactly predict the percentage of permeate flow rate lost from the high
temperature sanitations, which among other factors depends on:
1) Rate of temperature increase and decrease.
Do not exceed 20 GFD (34LMH) in any circumstances
Table 4: Pressures and operating parameters
Table 5: Operating and CIP parameters
2) Presence of other species like organics, ionic
and metallic compounds that could locally decrease or increase the temperature at the surface of the membrane.
3) Feed flow rate and specifically the heat trans-
fer rate to the membrane surface.
4) The thickness and geometry of the feed spac-
er used.
At optimum conditions measured in controlled
environment with deionized water, between 30%
and 50% of the original permeate flow rate was
lost before the element performance had stabilized after repeated heat treatments (over 90% of
this flow reduction occurred during the first heat
treatment). With the loss of permeate flow rate,
the salt rejection increases. The rate of cooling
and heating was not more than 5C (41°F) per minute, and the differential pressure drop per element did not exceed 2 psi.
Pilot testing based on the criteria noted above will
give the best operating parameters for any specific application.
Hot Water Sanitization
recommendations:
For optimal performance, Duratherm STD elements should always be cleaned using approved
CIP procedures and flushed with fouling free water before the sanitization process. Feed pressure
Page 2 FS1271EN
Salt Rejection
Figure 1: NaCl rejection for STD RO element