High-efficiency membrane distillation assembly and distillation method

Abstract

The invention provides a high-efficiency membrane distillation assembly. Membrane cores are arranged in a membrane shell, and membrane heads comprise the upper membrane head and the lower membrane head which are packaged at the two ends of the membrane shell respectively. The membrane distillation assembly is characterized in that the membrane cores are tubular membranes, and a cooling tube is arranged outside each tube in the corresponding tubular membrane, wherein the inner diameter of the cooling tube is larger than the outer diameter of the tube, and a steam channel is formed between the inner wall of the cooling tube and the outer wall of the tube in the tubular membrane; two independent cavities are formed in the upper membrane head, two independent cavities are formed in the lower membrane head, the two independent cavities in the upper membrane head are communicated with the two independent cavities in the lower membrane head through tubular membrane channels and the steam channels respectively, and an inlet and outlet opening is formed in one side of each independent cavity. Compared with the prior art, the high-efficiency membrane distillation assembly has the advantages of being stable in size, high in distillation efficiency, easy to clean and long in service life.

Description

technical field [0001] The invention belongs to the field of membrane distillation, and in particular relates to a high-efficiency membrane distillation component, a membrane distillation device and a distillation method using the above-mentioned high-efficiency membrane distillation component. Background technique [0002] Membrane distillation (MD) is a thermal desalination technology that uses the vapor pressure difference on both sides of the membrane as the driving force to make the volatile components in the aqueous solution pass through the membrane pores in the form of steam (usually water vapor) to condense on one side of the membrane. , so as to achieve the purpose of concentrating the feed liquid, while the other side of the membrane relies on the hydrophobicity of the membrane to block the aqueous solution. MD has the advantages of low energy consumption and normal pressure operation, and can be used for the treatment of high-concentration brine. It is currently ...

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Problems solved by technology

However, the current AGMD technology is still in the experimental stage, and the membrane module usually uses hollow fiber and plastic conduit as the core material, which has poor dimensional stability at high temperature, the gap between the membrane filament and the cooling tube is unstable, and the gap between the membrane and the cooling tube is unstable. There will be heat conduction, so the efficiency of the membrane module is unstable, the energy consumption is high, and there is a big gap with the theoretical prediction

On the other hand, since the cooling pipe is usually made of plastic material, the thermal conductivity is poor, and the heat transfer resistance of the cooling wall surface is large, so the water vapor cooling is insufficient, and the cold fluid heat supply is insufficient, which increases the heating and cooling load of the external equipment. Reduced efficiency

In addition, membrane distillation technology is usually used in high-salt solution situations. Membrane fouling of hollow fiber membranes (usually due to membrane crystallization leading to a decrease in hydrophobicity) is relatively serious, which will lead to a decrease in water production ratio and substandard water production. Therefore, combined with the size of the plate membrane The advantages of stability and easy cleaning, while taking advantage of the high thermal conductivity of some materials, the development of AGMD technology with high efficiency, process stability, and easy industrialization will have a wide range of application values

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