Membrane distillation sea water desalination method

Abstract

A membrane distilling process for desalinating seawater includes filtering seawater, bubbling while pressure floating to rmeove seaweeds and solid impurities, bubbling again to mix air with water to become emulsion and making the bubbles contain saturated water vapour, delivering it into a desalinating equipment containing one or more porous hydrophobic membranes to penetrate the emulsion containing a lot of saturated water vapour through the membrane, and condensing the water vapour to obtain fresh water.

Description

(1) Technical field [0001] The present invention relates to a membrane distillation method and applied equipment, in particular to a high-efficiency and low-cost membrane distillation seawater that can improve the water production function of seawater desalination, and can improve the separation efficiency of membrane distillation seawater desalination and greatly reduce costs. Dilution method. (2) Background technology [0002] At present, the desalination water production technology used in seawater desalination for commercial purposes in the world can be mainly divided into two categories: distillation and membrane separation. Distillation methods also include: Multi-Stage Flash (Multi-Stage Flash or MSF), Multi-Effect Distillation (Multi-Effect Distillation or MED) and Vapor Compression (Vapor Compression or VC). Membrane separation methods mainly include reverse osmosis (Reverse Osmosis or RO) and electrodialysis (Electro Dialysis or ED). [0003] The desalination tec...

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Problems solved by technology

[0021] 4. The mechanical strength required for the film is low

[0025] 2. During the mass transfer process, temperature polarization may occur on the surface of the film (Temperature Polarization)

[0026] 3. During the mass transfer process, concentration polarization may also occur on the surface of the film (ConcentrationPolarization)

[0028] 5. Because the limited temperature difference is used for the permeation mass transfer of liquid-gas balance, the mass transfer rate is relatively slow, so it is necessary to maintain a large temperature difference between the two measured fluids of the membrane to make up for this problem, but it is limited by the operation of the membrane material The temperature cannot be too high and the energy consumption efficiency is poor, so that it cannot compete with general commercial technology

[0030] 7. For mass production, a large amount of energy and membrane tubes must be provided, which is not in line with economic benefits

[0031] In summary, although the previous membrane distillation method is theoretically feasible, it has not been successfully commercialized because the amount of steam produced is too small. The present invention proposes an improvement method for the above-mentioned shortcomings

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