A method for recovering and utilizing secondary steam from ammonia distillation

Abstract

The invention provides a recycling method for steamed ammonia secondary steam and relates to the technical field of industrial waste steam recycling. The method comprises the following steps of: 1) condensing steamed ammonia secondary steam containing ammonia and carbon dioxide in a condenser at a temperature of 60-80 DEG C, returning the condensate back to a ammonia still, and pumping out non-condensable gas containing ammonia and carbon dioxide by a vacuum pump and feeding into an adsorption tower; 2) feeding water which can absorb ammonia and carbon dioxide from the non-condensable gas into the adsorption tower, wherein absorption liquid containing ammonium bicarbonate is obtained after ammonia and carbon dioxide in the non-condensable gas are absorbed by water; and 3) producing baking soda by using the absorption liquid obtained in the step 2) in a double decomposition mode. The recycling method is easy to carry out without ammoniacal brine, and is suitable for workshops which produce baking soda in a double decomposition mode; by adopting the method, ammonia and carbon dioxide in the steamed ammonia secondary steam are recycled, so that environment pollution can be reduced and the production cost of enterprises is reduced.

Description

technical field [0001] The invention relates to the technical field of recovery and utilization of industrial waste steam, in particular to a method for recovery and utilization of secondary steam from ammonia distillation. Background technique [0002] Na + , NH 4 + , Cl - 、HCO 3 - and other ingredients. The recovery of ammonium chloride and sodium chloride by thermal method must first remove free ammonia and bicarbonate in the mother liquor. At present, there are two main methods for dealing with free ammonia and bicarbonate in China: one is to add hydrochloric acid, and the other is to distill ammonia. The acid addition method has the advantages of simple method, less investment in equipment, and low energy consumption, but it has disadvantages such as high cost, inaccurate addition, incomplete removal, affecting subsequent evaporation efficiency, increased energy consumption, and equipment corrosion. Ammonia distillation is a method commonly used in the industry....

AI Technical Summary

Problems solved by technology

The acid addition method has the advantages of simple method, less investment in equipment, and low energy consumption, but it has disadvantages such as high cost, inaccurate addition, incomplete removal, affecting subsequent evaporation efficiency, increased energy consumption, and equipment corrosion.

Ammonia distillation is a method commonly used in the industry. It has the advantages of low cost and high removal rate. However, this method has the disadvantages of high energy consumption and large investment in equipment, and it has the disadvantages of secondary steam generated in the process of ammonia distillation. Contains a certain amount of ammonia and carbon dioxide, if the above-mentioned secondary steam is directly discharged, it will not only cause waste of resources but also pollute the environment

[0003] At present, the soda ash plant uses ammonia brine to absorb the secondary steam of ammonia distillation, but for factories producing baking soda by double decomposition method, because ammonia brine is not used in the production process and no ammonia brine is produced, if ammonia brine is specially purchased for treatment The cost of the above-mentioned secondary steam is too high, so the use of ammonia brine absorption method to process the secondary steam of ammonia is not suitable for factories producing baking soda by double decomposition

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