Method and device for distillating vacuum film by directly utilizing vapor compression heat pump

Abstract

The invention discloses a method and a device for distillating a vacuum film by directly utilizing a vapor compression heat pump. The method adopts a vapor compression machine to directly compress the vapor of a transmission side of a film assembly, the compressed high-temperature high-pressure vapor passes through a heater and a preheater in sequence, and the raw materials also pass through the heater and the preheater. In the process, the heat exchange is carried out between the temperature of the vapor and the raw materials to realize the condensation, temperature reduction and heat release of the vapor, so that the additional refrigeration working medium and the evaporator and the condenser thereof are not needed, and a vacuum pump is saved by using the negative pressure formed by the vapor compression machine during absorption of the vapor as a vacuum source; and simultaneously the concentrate from the film assembly exchanges heat with the raw materials through the preheater. The invention saves energy, simplifies the heat pump system, reduces the equipment cost, and can be applied to the purifying and recycling of waste water, water desalination of sea water, bitter water and salt water, concentration of juice and traditional Chinese medicine extract and the like.

Description

technical field [0001] The invention belongs to the technical field of membrane distillation, and relates to a method and a device for vacuum membrane distillation by using a direct vapor compression heat pump. Background technique [0002] Membrane distillation is a cheap and efficient new membrane separation technology. It can use cheap energy such as solar energy, geothermal heat, and factory waste heat. It can be carried out under normal or negative pressure, with simple equipment and convenient operation. It has a wide range of applications in seawater, brackish water desalination to produce drinking water and drinking water purification, high-purity water preparation, wastewater treatment, fruit juice, traditional Chinese medicine concentration, etc. [0003] Membrane distillation is a membrane separation process that combines membrane technology and evaporation process. The membrane used is a hydrophobic microporous membrane that is not wetted by the solution to be tr...

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Problems solved by technology

[0007] Chinese patent 200810059179.2 discloses a membrane distillation seawater desalination system using economic energy, including membrane modules, seawater storage tanks and fresh water storage tanks. The concentrated seawater outlet and steam outlet of the membrane module are connected to the same heat pump to realize the recovery of steam heat. However, there are still some problems in the way of indirect heating of seawater by heating the concentrated seawater through a heat pump and then flowing it back to the seawater storage tank, and there is no description of what type of heat pump is used

[0010] In the process of preparing pure water by vacuum membrane distillation technology in China, Ren Jianxun and others used a compression heat pump to recover the latent heat of condensation of water vapor, but they used indirect vapor compression, that is, the phase change of the refrigerant instead of water vapor was used to generate water. To achieve heating and cooling, the process is relatively complicated

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