Continuous evaporation and crystallization device and method capable of saving energy by mechanical steam recompression

Abstract

The invention relates to a continuous evaporation and crystallization device and method capable of saving energy by mechanical steam recompression. The continuous evaporation and crystallization device comprises a preheater, a film-rising evaporator, a compressor, a circulating evaporator, a gas-liquid separator and a crystallization separator, wherein the gas-liquid separator is provided with an inlet, a first outlet, a second outlet and a third outlet; the preheater is connected with the film-rising evaporator by a pipeline, and the film-rising evaporator is connected with the inlet of the gas-liquid separator; the compressor is connected between the gas-liquid separator and the film-rising evaporator by a steam conveying pipeline; the circulating evaporator is connected between the second outlet and the inlet by a pipeline; cooling water after heat exchange of the film-rising evaporator and cooling water after heat exchange of the circulating evaporator are used as heat sources of the preheater, and are fed into the preheater for performing supplement heating on materials flowing through the inner part of the preheater; and the crystallization separator is connected with the third outlet in the gas-liquid separator. The continuous evaporation and crystallization device and method have the advantages that the cost is low, the materials are not wasted, the continuity is good and the energy-saving effect is good.

Description

Technical field [0001] The invention relates to a continuous evaporation and crystallization device for energy saving through mechanical vapor recompression, and a continuous evaporation and crystallization method using the device. Background technique [0002] Mechanical Vapor Recompression (Mechanical Vapor Recompression) technology is a high-efficiency, energy-saving and environmentally friendly technology. This technology mainly uses a mechanical device to transfer the thermal energy of low-temperature objects to higher-temperature objects. The specific process is to compress the secondary steam generated in the evaporation process through a mechanical steam compressor (the compression medium is generally water vapor), so that the temperature and pressure are increased, and the enthalpy value is increased, so that the compressed steam can be directly used as The heating source of this level system. The compressed steam enters the heating outer tube to heat the solution. The ...

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Problems solved by technology

[0003] Although many continuous evaporation crystallization devices and methods using mechanical vapor recompression technology are disclosed in the prior art, and many mechanical vapor recompression continuous evaporation crystallization systems generally only have a single-stage steam compressor to supply heat to the evaporator, and in the crystallizer part , the material is still not supplied with a large amount of heat, resulting in poor crystallization effect of the existing mechanical vapor recompression continuous evaporation crystallization system, such as problems such as fine crystal particle size

Of course, some manufacturers will add steam pipes to supplement the heating of the crystallization part, but this greatly increases the complexity of the MVR system and relies on steam boilers, making the MVR system lose its original significant advantage - get rid of the dependence on steam boilers

In view of these problems, the publication number is CN103203116A Chinese Invention Patent Application Publication Specification discloses a mechanical vapor recompression continuous evaporation crystallization system and method to solve the above problems, the mechanical vapor recompression continuous evaporation crystallization system uses two mechanical vapor compression machine, and the two compressors supply heat to the evaporator and the crystallizer respectively, and also recover the sensible heat of the condensed water for preheating, but the continuous evaporation and crystallization system uses two mechanical steam compressors, and two mechanical steam compressors are purchased The equipment cost of the compressor is very high, and there is no reasonable structure to preheat the material to the bubble point temperature, so the energy consumption of starting two compressors is also high, and the structure is complicated, resulting in unsatisfactory energy saving effect

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