Sea water desalting membrane distillation system with high efficiency and low cost

Abstract

The efficient and cheap sea water desalting membrane distillation system includes one sea water feeding loop; one micro bubble forming unit to pump sea water, pressurize and emulsify sea water into work liquid containing saturated water vapor; one desalting unit with at least one ventilation room, porous hydrophobic membranes inside the ventilation room, separate high temperature sea water regions, into which work liquid containing saturated water vapor is pumped into, and low temperature condensated fresh water regions; and one condensating desalting unit to condensate fresh water connected successively.

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 system. (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...

AI Technical Summary

Problems solved by technology

[0009] 1. Without good pre-treatment equipment, fouling on the membrane surface is still very high, reducing the service life of the membrane tube

[0010] 2. During the mass transfer process, concentration polarization may also occur on the surface of the film (ConcentrationPolarization)

[0011] 3. According to the saturated vapor pressure data of water vapor, under normal operating conditions, when the temperature rises from 25°C to 30°C, the saturated vapor pressure increases from 0.461psi to 0.616psi. The amount of water is limited, that is, the saturated vapor pressure only increases by 0.031psi per degree Celsius on average, which is too little, so it has not been successfully commercialized

[0012] 4. Because the limited temperature difference is used for the permeation mass transfer of liquid-gas balance, the mass transfer rate is relatively slow. Therefore, 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

[0014] 6. For mass production, a large amount of energy and membrane tubes must be provided, which is not in line with economic benefits

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