Process method for concentrating light salt brine by adopting five-effect down-flow evaporation process

Abstract

The invention provides a process method for concentrating light salt brine by adopting a five-effect down-flow evaporation process, and the method comprises the following steps of: firstly, heating feed salt brine by adopting live steam, taking generated secondary steam as a heating source of the next effect, and so on, thus achieving the purpose of concentrating light salt brine. The process method provided by the invention is low in energy consumption and small in investment, and by controlling reasonable operation pressure difference among all the effects, the design parameters of the first four-effect falling film evaporator equipment are consistent, so that the design and manufacturing period is greatly shortened; the evaporator of each effect is provided with a backflow control pipeline, so that the operation flexibility is high; the inter-effect condensate directly enters the shell pass of the next-effect evaporator to recover heat by reasonably arranging the pipe orifice height difference and a manual control valve, so that an inter-effect condensate tank and a condensate delivery pump are omitted; a large-flow forced circulation process is adopted in the fifth effect, a large amount of light salt brine can be effectively and rapidly concentrated to a nearly saturated state, and the crystallization phenomenon in the evaporation process is prevented.

Description

technical field [0001] The invention belongs to the technical field of evaporation and concentration in the field of chemical industry, and in particular relates to a process method for extracting concentrated and light brine by adopting a five-effect downstream evaporation process. Background technique [0002] In the chlor-alkali industry, there are mainly diaphragm and ion-exchange membrane electrolysis processes. With the development of technology, the ion-exchange membrane method has gradually become the mainstream chlor-alkali process due to its advantages of low energy consumption, high product quality, and no pollution, and gradually replaces the existing diaphragm. Due to the pressure of environmental protection and cost, more and more caustic soda plants have gradually upgraded the diaphragm production process to the ion exchange membrane process. The anolyte of the electrolytic cell using the ion-exchange membrane electrolysis process is dechlorinated to obtain li...

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Problems solved by technology

[0006] In view of this, the present invention aims to overcome the above-mentioned defects in the prior art, and provides a process method for extracting concentrated brine using a five-effect downstream evaporation process; it solves the problem of high energy consumption for evaporating light brine returning to the electrolysis section in the chlor-alkali industry. Insufficient problems such as easy crystallization to achieve the purpose of reducing energy consumption, saving investment, and reducing operating costs

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