Device and method for air-blowing vacuum membrane distillation

Abstract

The invention provides a device and a method for air-blowing vacuum membrane distillation. The device for air-blowing vacuum membrane distillation comprises the following sequentially-connected parts:a water tank arranged on the side of raw water; a water pump which is connected with the water tank and is used for pumping the raw water in the water tank; a compressed air inlet which is arranged on the downstream of the water pump and is used for blowing low-pressure compressed air to the raw water; a gas-liquid mixer used for mixing the compressed air and liquid to form gas-liquid mixed fluid; a hydrophobic membrane component used for processing the gas-liquid mixed fluid; and a vacuum generation device arranged on the effluent side of the hydrophobic membrane. In the device and the method, the compressed air is blown into the raw water side of the membrane when vacuum is generated on effluent side of the membrane. Under the suction action of the vacuum, water vapor and part of compressed air passes through the hydrophobic membrane together. As blowing and sweeping actions of the compressed air deliver the water vapor to the other side of the membrane, mass transfer efficiency isimproved. The requirements on the vacuum degree of the effluent side are reduced and equipment cost is reduced. Meanwhile, membrane pollution is effectively relieved.

Description

technical field [0001] The invention relates to a membrane distillation device and method, in particular to a membrane separation treatment method for water purification treatment and chemical separation. Background technique [0002] Membrane distillation has attracted worldwide attention and research in recent years. Compared with ordinary evaporators, one of the most notable features of membrane distillation is that the evaporation area per unit volume is large, so that the device can be operated efficiently in the normal pressure and lower temperature evaporation process, and the vapor phase space required for distillation operation very small. Compared with reverse osmosis, membrane distillation is a heat-driven process with low operating pressure, so the requirements for membrane mechanical properties are low, equipment costs are also low, and process safety is improved. Moreover, membrane distillation has low operating pressure and high desalination rate , less memb...

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Problems solved by technology

[0007] However, so far, the above four membrane distillation methods have some problems such as high energy consumption, low efficiency, and low reliability.

For example, although the process equipment of direct contact membrane distillation is simple, due to the direct contact of cold and heat sources, the energy consumption of the equipment is high, and the leakage of hydrophobic membrane is prone to occur; although the membrane flux of vacuum membrane distillation is large, But higher system requirements

Air-gapped membrane distillation and flow-swept membrane distillation have lower throughput

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