Reduced-pressure multi-effect membrane distillation method and device thereof

Abstract

The invention aims to provide a reduced-pressure multi-effect membrane distillation method and a device thereof; in a membrane distillation combined element, a hot feed liquid flows from top to bottom, negative-pressure evaporation occurs in the flowing process, and the hot feed liquid is cooled; generated steam heats cold fluid through a heat exchange wall and is condensed; meanwhile, a cold feedliquid flows from bottom to top, and negative-pressure evaporation occurs while the cold feed liquid is heated by the heat exchange wall. The evaporation cooling of the hot feed liquid and the heatedtemperature rise of the cold feed liquid are continuous stepless processes, and efficient multi-effect evaporation can be realized. According to the reduced-pressure multi-effect membrane distillation method provided by the invention, condensation of water vapor generated in the membrane distillation process is coupled with the heating process of the feed liquid, so that the membrane distillationflux is relatively high under the condition of a high water production ratio, and meanwhile, the dosage of external cooling water can be remarkably reduced. Through the multi-effect membrane distillation process designed by the invention, the membrane distillation process with high efficiency and low energy consumption can be realized, and the heat recovery rate is high.

Description

technical field [0001] The invention relates to a membrane distillation method and a device thereof, in particular to a vacuum multi-effect membrane distillation method and a device thereof for concentrated treatment of high-salinity waste water and separation and concentration of industrial materials. Background technique [0002] Membrane distillation technology is a new type of liquid separation technology combined with membrane technology and traditional distillation technology. Compared with ordinary evaporators, one of the most notable features of membrane distillation is that the effective evaporation area per unit volume is large, so that the device can be used under normal pressure, It operates efficiently in the evaporation process at a lower temperature, and the equipment is made of plastic materials, which avoids the corrosion of metal materials in the treatment of high-salinity materials. Membrane distillation is a membrane separation process that uses a hydroph...

AI Technical Summary

Problems solved by technology

However, due to the phase change process in the separation process, so far, membrane distillation technology has the problem of high energy consumption.

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