| 摘要 |
PURPOSE:To effectively remove scales on the membrane surface by adding small-particle solid matter to a liq., mixing a gas into the liq., and supplying the liq. to the membrane module as the three-phase current of liq., gas, and solid. CONSTITUTION:The raw liq. 1 is supplied by a feed pump 6 from a raw liq. tank 2 into a header tank 3, the small-particle solid matter 7 of ion-exchange resin, etc., is added to the liq. in the header tank 3, and the liq. is allowed to flow down through a downcomer 10. A gas is injected into the raw liq. at a gas-liq. mixer 12 in the middle of a riser 11. The injected gas rises through the central part of the passage in the membrane module 15, the raw liq. rises along the outer peripheral part of the passage, namely the inner side surface of the tubular permeable membrane in the membrane module 15, hence the small-particle solid matter 7 flowing along with the raw liq. is brought into contact with the scales deposited on the inner side surface of the tubular permeable membrane, and the scales are scraped off. The liq. permeated through the tubular permeable membrane is discharged from a discharge pipe 21, and the concd. liq. is returned to the header tank 3 through a return pipe 19.
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