Ammonia-process alkali production system for flash evaporation of circulating water by virtue of distilled ammonia waste liquid

Abstract

The invention relates to the field of alkali production industry and particularly relates to an ammonia-process alkali production system for flash evaporation of circulating water by virtue of a distilled ammonia waste liquid. The ammonia-process alkali production system comprises an ammonia-process alkali production unit, an evaporation-concentration unit, a distilled ammonia waste liquid heat exchanger and a flash evaporator, wherein the evaporation-concentration unit is arranged at the front end of a brine liquid inlet of the ammonia-process alkali production unit, the distilled ammonia waste liquid heat exchanger is arranged at a distilled ammonia waste liquid outlet of the ammonia-process alkali production unit, and the flash evaporator is arranged at the front end of a steam inlet of the evaporation-concentration unit. Circulating water in the distilled ammonia waste liquid heat exchanger is heated by the distilled ammonia waste liquid from the ammonia-process alkali production unit and enters the flash evaporator to produce flash evaporation steam, the flash evaporation steam enters the evaporation-concentration unit to evaporate and concentrate brine, and concentrated brine enters the ammonia-process alkali production unit for producing alkali. Compared with an existing ammonia-process alkali production system, the ammonia-process alkali production system provided by the invention has the advantages that the consumption of a brine heating source is reduced, and meanwhile, the waste heat of the distilled ammonia waste liquid is recycled and utilized, so that the production cost of the ammonia-process alkali production system is lowered.

Description

technical field [0001] The invention relates to the field of soda-making industry, in particular to an ammonia-based soda-making system using ammonia distillation waste liquid to flash circulated water. Background technique [0002] Sodium carbonate, commonly known as soda ash and soda, is an important raw material for glass, paper, soap, detergent, textile, leather and other industries. It is also often used as a softener for hard water and for the manufacture of sodium compounds. Its industrial production methods mainly include ammonia-soda method and combined soda-production method. [0003] The ammonia-soda method (also known as the Solvay method) is a soda ash method invented by the Belgian engineer Solvay (1838-1922) in 1892. He uses salt (sodium chloride), limestone (calcined to produce quicklime and carbon dioxide), and ammonia as raw materials to produce soda ash. Ammonia gas is passed into saturated saline to form ammonia brine first, and then carbon dioxide is p...

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Problems solved by technology

[0011] The temperature of the ammonia distillation waste liquid produced in the production process of the ammonia soda method is about 90°-98°, and there is a lot of waste heat. In the existing production process, on the one hand, the ammonia distillation waste liquid will be directly discharged, and the ammonia distillation cannot The waste heat of the waste liquid is effectively recycled. On the other hand, in order to improve the efficiency of alkali production, it is necessary to heat the brine with a heat source to increase the concentration of the brine. These two factors cause energy waste.

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