Seeded precipitation spent liquor six-effect evaporation and concentration process and six-effect pipe falling film evaporator set

Abstract

The invention relates to a seeded precipitation spent liquor six-effect evaporation and concentration process and a six-effect pipe falling film evaporator set. The process mainly includes the steps:concentrating 50%-60% evaporation stock solution and 40%-50% evaporation stock solution to obtain first discharge mother liquor and second discharge mother liquor; leading 20%-50% first discharge mother liquor to perform forced salt elimination when the impurity content of the solution exceeds process requirements; mixing the first discharge mother liquor and the second discharge mother liquor bya mother liquor discharge pump and then conveying the mixed mother liquor to a mother liquor tank. The six-effect pipe falling film evaporator set mainly comprises an I-effect evaporator to a VII-effect evaporator, a first from evaporator drier to a fourth from evaporator drier, a stock solution flash evaporator, various effect condensation water tanks and the like. The stock solution is concentrated in a segmented manner, secondary steam generated by all the evaporators, secondary steam produced by flash evaporation of condensed water, secondary steam generated by a forced circulating salt elimination evaporator and secondary steam generated by the from evaporator driers are sufficiently used, and the evaporation efficiency of the whole evaporation and concentration process is greatly improved.

Description

Technical field: [0001] The invention relates to a six-effect evaporation concentration process for seed separation mother liquor and a six-effect tube-type falling film evaporator group. Background technique: [0002] Evaporation technology and its equipment are indispensable and extremely important production links in the alumina production industry and chemical production industry. Its main purpose is to concentrate and evaporate excess water in the production solution to increase the concentration of the solution to meet the requirements of the production process for solution concentration, while maintaining the water balance in the production cycle system. [0003] In the last century, the evaporator used in my country's alumina production was still an old-fashioned "external heating natural circulation" evaporator. Its technical level and equipment were very backward, which caused my country's alumina production to stagnate for decades, lacking high efficiency, energy ...

AI Technical Summary

Problems solved by technology

[0004] With the continuous development and technological innovation of the alumina industry, the shortcomings and defects of the six-effect tube falling film evaporator group used in the market are also highlighted: such as the problem of alkali in the secondary steam, high frequency of equipment maintenance (especially Ⅰ effect evaporator), evaporation efficiency and production capacity still have high room for improvement, etc.

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