ETC membrane is used to remove dissolved carbon dioxide in water. Product water carbon dioxide content can be decreased to 0.5ppm.
membrane contactor is a kind of special hydrophobic hollow fiber array made of polymer material. Then the array is spiral-wounded onto a water distribution tube, and then the tube is installed into a housing (at the same time, a baffler is formulated inside the housing).
Hollow fiber → Knitted fiber (under microscope) → Knitted fiber (naked eyes) → End surface
Structure of membrane contactor:
Features of membrane contactor:
1) Hollow fibers are knitted into an array, so that a certain space can be kept between these fibers. In this way, thousands of fibers are connected as a whole array which can resist strong water flow and will not break. Besides, the mass transfer efficiency can be improved in the array structure.
2) High fiber density makes it possible of ultimate gas removal from water;
3) Central tube water distribution + Middle baffler structure, change the water flow direction to flush vertically towards hollow fibers, which can improve the mass transfer efficiency between shell side and lumen side.
CO2 removal from water is a necessary process in many industries. Dissolved CO2 in feed water of EDI/CDI and ion exchange column should be removed. Using membrane contactor to remove dissolved CO2 is an easy method without chemical dosing and frequent chemical regeneration, because it is a 100% physical process. At the same time, operation cost is saved and it is more friendly to environment.
Traditional CO2 removal technology is “alkali dosing + 2nd RO” process, while using membrane contactor includes only one step: CO2 is taken out by vacuum pump and sweep gas.
It has the following advantages compared with “alkali dosing + 2nd RO” process:
|
Process
|
UF+RO+ETC+EDI
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UF+RO+RO+EDI
|
|
EDI capacity
|
300m3/h
|
300 m3/h
|
|
Water recovery
|
70.80%
|
67.56%
|
|
Annual water consumption
|
3661856 m3
|
3836507 m3
|
|
Annual water consumption difference
|
Saving 174651m3
|
---
|
|
Annual power consumption
|
4.49 million KWH
|
6.89 million KWH
|
|
Annual power consumption difference
|
Saving 2.4million KWH
|
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|
|
Equipment investment
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2.33 million USD
|
3.17 million USD
|
|
Equipment investment difference
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Saving 0.83 million USD
|
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Specifications of ETC membrane contactor:
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Item
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Parameters
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|
Model
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ETC-6×28
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ETC-10×28
|
|
Application
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CO2 removal from pure water
|
|
Flux
|
1~8m3/h
|
8~25m3/h
|
|
Fiber material
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Polypropylene
|
|
Dimensions
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Ø6×28 inch
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Ø10×28 inch
|
|
Liquid/gas contact area
|
45m2
|
120m2
|
|
Inner/outer diameter of fiber
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0.2/0.3mm
|
|
Housing material
|
UPVC
|
|
PH resistance range
|
1~13
|
|
Working temperature
|
5~60℃
|
|
Max inlet water pressure
|
6.0bar
|
|
Connect pipe size
|
DN32 / DN20
|
DN40 / DN20
|
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