PURPOSE: To enable the prevention of a decrease in a removal rate by supplying a low temp. liquid to a reverse osmosis device while maintaining the operating pressure after treating a high temp. liquid and stopping the operation after cooling the membrane.
CONSTITUTION: The original liquid to be treated is fed from a raw material tank 1 by a supply pump 2 through a filter 3 and a heat exchanger 4 to a high pressure pump 5 and after the liquid is pressurized to a high pressure with the pump 5, the liquid is supplied to a reverse osmosis device 6. The supply of cooling water to the heat exchanger 4 is stopped in this case and the high temp. original liquid to be treated of ≥35°C (high temp. liquid) is supplied as it is to the device 6. Cooling water 7 is supplied to the heat exchanger 4 to cool the high temp. liquid down to ≤30°C in the stage of shutdown. The low temp. liquid produced in such a way is pressurized with the pump 5 and is supplied to the device 6. The operation is stopped when the permeated liquid 9 and thickened liquid 8 obtd. by the treatment drop down to ≤30°C, the operation is stopped. The reverse osmotic membrane is cooled and hardened in such a way to avoid the contact thereof with spacers for accelerating the non-permeated liquid flow, whereby the decrease in the removal rate is prevented.
BABA YASUO
HAYASHI KUNIHIKO
KOMURA AKIO
| JPS524481A | 1977-01-13 |
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