3M MEMBRANA Liqui-Cel, Инструкция по уборке

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15
Liqui-Cel
®
Membrane Contactors Cleaning Guidelines
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Table 6: Cleaning Protocol for Mineral Deposit Removal
Step Description / Flow Schematic Chemical Solution Time (min.)
1 Water flush/Once-through Filtered (10 micron) water 5 min
2
Acid wash / recirculate (repeat if
necessary)
5% w/w citric, or 3% Nitric or phosphoric, or a
combination of 3% Nitric and 3% phosphoric acid solution
using filtered (10 micron) water ambient temperature
30 min to 2
hours
3 Drain contactor
4
Water flush /
Once through
Filtered (10 micron) water
Flush until pH in = pH out
5 to 10 min
If silica, aluminum or a combination of these is found in the inlet water source, it is likely that they
will precipitate on the membrane surface. If CO
2
is used as a sweep gas, precipitation can occur
depending on the concentration and the water pH shift. For aluminum precipitation follow the
mineral deposit removal procedure. For silica precipitation refer to the
Biological Soil Removal
Procedure, section VI , but increase the caustic concentration to 5.5% by weight and increase the
temperature to 50 ºC. If possible, the flow rate of the cleaning solution should be similar to the
process water flow rate used during normal operation. In addition, it is advisable to keep the
direction of the water flow consistent during cleaning.
Illustration 3: Flow Schematic for Acid Cleaning to Remove Mineral Deposits
F
P
= Flow Indicator
= Pressure Gauge
= Valve
P
Drain
P
Recirculation
Once-
through
Drain
F