Low pressure superheated steam assisted evaporation crystallization device and crystallization process

Abstract

The invention relates to a low-pressure superheated steam-assisted evaporative crystallization device. A pre-crystallizer is added between an evaporator and a crystallizer. The pre-crystallizer consists of three major parts, i.e., a pre-crystallizer tank body, a concentrated solution distributor and a steam speed-up distributor. A material is concentrated by the evaporator, then, the concentrated material is conveyed into the pre-crystallizer by a concentrated solution conveying pump, a concentrated solution is uniformly distributed in the pre-crystallizer through the concentrated solution distributor, low-pressure saturated steam generated by a low-pressure saturated steam generator is subjected to heat exchange with a heat exchanger and then is changed into low-pressure superheated steam, the low-pressure superheated steam enters the pre-crystallizer through a steam speed increaser and is subjected to contact heat exchange with the concentrated solution from top end to bottom, moisture remaining in the concentrated solution is taken away, thus, the effect of further evaporating heat exchange of the material is achieved, and finally, the material is subjected to separation by crystallization in the crystallizer. The low-pressure saturated steam generator is generated in a water bath, so that preheat of an evaporative crystallization system can be used for heating a water-bath device, and thus, the effect of efficiently utilizing residual heat is achieved.

Description

technical field [0001] The invention relates to a crystallization device, specifically designs a low-pressure superheated steam assisted evaporation crystallization device, and belongs to the technical field of evaporation crystallization equipment. Background technique [0002] In the process of evaporation and crystallization, a considerable amount of low-temperature or low-pressure steam will be produced. Except for preheated materials or non-condensable gases, these steams will basically be condensed and discharged as condensed water. So how to make full use of this part of steam becomes particularly important under the background of energy shortage and energy crisis. Of course, the low-temperature or low-pressure steam generated during the evaporative crystallization process has been applied in the existing technology to a certain extent, and considerable results have been achieved. For example, for the mechanical compression of the secondary steam, the MVR technology ...

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Problems solved by technology

In the drying technology, some scholars have begun to conduct drying experiments on low-pressure superheated steam, and have obtained some physical and chemical advantages of low-pressure superheated steam during drying, but there are great technical difficulties in the specific practical operation process. The generation of steam is not complicated. Due to the inconvenient collection of low-pressure steam in the existing evaporation and crystallization technology, the practical operation is more difficult. Those skilled in the art have been trying various methods, but the effect is not very good. ideal

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