MVR (Mechanical Vapor Recompression) continuous evaporating crystallizing system

Abstract

The invention relates to an MVR (Mechanical Vapor Recompression) continuous evaporating crystallizing system. The system comprises a raw material inlet, a water compensating inlet, a preheater, a climbing film evaporator, an air-liquid separator, a compressor, a pipeline heater, a crystallizing separator and four control circuits; an inlet, a first outlet, a second outlet and a third outlet are formed in the air-liquid separator; the preheater is connected with the climbing film evaporator through a pipeline; the climbing film evaporator is connected with the inlet of the air-liquid separator; the compressor is connected between the air-liquid separator and the climbing film evaporator through a steam conveying pipeline; a circulating evaporator is connected between the second outlet and the inlet; cooing water subjected to heat exchange through the climbing film evaporator and cooling water subjected to heat exchange through the circulating evaporator are treated as heat sources of the preheater; the cooling water output end of the preheater and the water supplementing inlet are used for compensating water to the system together; the crystallizing separator is connected with the third outlet of the air-liquid separator; the four control circuits are arranged in the system. The system has optimal and stable parameters, achieves water saving, energy saving and raw-material saving effects and also has a good crystallizing effect.

Description

technical field [0001] The invention belongs to an evaporation crystallization system, in particular to an MVR continuous evaporation crystallization system with energy-saving and water-saving effects. Background technique [0002] Mechanical vapor recompression Mechanical Vapor Recompression technology is a highly efficient, energy-saving and environmentally friendly technology, referred to as MVR. Although many MVR continuous evaporation and crystallization systems using mechanical vapor recompression technology are disclosed in the prior art, there are not many of them in industrial applications. [0003] Due to unreasonable process design, many mechanical vapor recompression continuous evaporation and crystallization systems generally only have a single-stage steam compressor to supply heat to the evaporator. The crystallization effect of the recompression continuous evaporation crystallization system is not good, such as problems such as small crystal particle size. O...

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Problems solved by technology

[0003] Due to unreasonable process design, many mechanical vapor recompression continuous evaporation and crystallization systems generally only have a single-stage steam compressor to supply heat to the evaporator. The crystallization effect of the recompression continuous evaporation crystallization system is not good, such as the problem of 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

[0004] 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 cooling water for preheating, but the continuous evaporation and crystallization system uses two mechanical steam compressors, purchased The equipment cost of two mechanical steam compressors is very high, and there is no reasonable structure to preheat the material to the bubble point temperature, so the energy consumption of starting the two compressors is also high, and the structure is complicated, resulting in unsatisfactory energy saving effect

[0005] In addition, in addition to saving energy, the existing MVR continuous evaporation and crystallization system rarely considers the recycling of waterways, resulting in the continuous production process of the existing MVR continuous evaporation and crystallization system. Heat energy, to prevent the pollution of cooling water, and a large amount of new steam is required to fill in, wasting water resources

[0006] Finally, none of the existing MVR continuous evaporation and crystallization systems has established an automatic control system to control its parameters, resulting in a low level of optimization for the existing MVR continuous evaporation and crystallization systems, affecting crystallization quality control and crystallization energy consumption

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