Parallel type multi-effect vacuum membrane distillation apparatus and method

Abstract

The invention discloses a parallel type multi-effect vacuum membrane distillation apparatus and method and belongs to the field of membrane distillation. The parallel type multi-effect vacuum membrane distillation apparatus which is low in energy consumption comprises n-stage parallel membrane distillation units; tube passes of a first feed liquid tank, a booster pump, a hollow fiber membrane module form a first closed circulation loop; tube passes of the hollow fiber membrane modules of the second stage to the nth stage, the shell pass of a shell-and-tube heat exchanger of the former stage, the feed liquid tank and the booster pump of the corresponding stage form a second closed circulation loop, a third closed circulation loop..., an nth closed circulation loop. The tube pass of a shell-and-tube heat exchanger of the nth stage is communicated with a cooler. In each stage, the outlet of the shell pass of the hollow fiber membrane module and a finished product collection tank are communicated with the inlet of the tube pass of the corresponding shell-and-tube heat exchanger; a thermometer is arranged on a connection pipeline between the booster pump and the hollow fiber membrane module. Besides, the outlet of the tube pass of the shell-and-tube heat exchanger of the first stage to the outlet of the tube pass of the (n-1)th stage are respectively communicated with the outlet of the shell pass of the hollow fiber membrane module of the next stage and then communicated with the inlet of the tube pass of the shell-and-tube heat exchanger of the next stage, and the outlet of the tube pass of the nth shell-and-tube heat exchanger is communicated with a vacuum pump.

Description

technical field [0001] The invention relates to the field of membrane distillation, in particular to a parallel multi-effect vacuum membrane distillation device and method. Background technique [0002] Vacuum membrane distillation technology is a new type of membrane separation technology, which is based on passing the hot feed liquid of the substance to be separated through one side of the separation membrane (ie, the hot side), and evacuating the other side of the separation membrane (ie, the vacuum side), Thus, a transfer vapor pressure difference is formed on both sides of the separation membrane, and the water in the hot liquid is vaporized on one side of the separation membrane to form steam, and the steam will pass through the membrane pores of the separation membrane to the separation membrane driven by the transfer vapor pressure difference. On the vacuum side, it is condensed into pure water on the vacuum side, so as to realize the separation of water and other su...

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Problems solved by technology

[0005] Since the energy consumption in the vacuum membrane distillation process is mainly to supplement the sensible heat of the liquid consumed by the evaporation of water, and the latent heat of evaporation of water is relatively large, the existing technology uses condensed water to condense the steam obtained after the evaporation of water, which requires a large amount of condensation water, resulting in excessive energy consumption

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