Method for treating low-concentration ammonia-containing tail gas

Abstract

The invention belongs to the field of environmental protection, and discloses a method for treating low-concentration ammonia-containing tail gas. The method for treating the low-concentration ammonia-containing tail gas comprises the following steps: low-concentration ammonia-containing tail gas enters an efficient absorber from the top, an ammonium hydrogen sulfate mother liquor is jetted to the lower part of the efficient absorber so as to be in sufficient contact reversely, and ammonia in tail gas is absorbed primarily; the ammonia-containing tail gas absorbed primarily and the ammonium hydrogen sulfate mother liquor enter the lower part of the absorption tower together, the ammonium hydrogen sulfate mother liquor is left at the bottom of the absorption tower, the tail gas ascends to the middle part of the absorption tower, acid dilute phase ammonium hydrogen sulfate mother liquor is sprayed, and ammonia in the tail gas is absorbed for a secondary stage; the tail gas after second-stage absorption continues to ascend to the upper part of the adsorption tower, a washing liquid is sprayed, ammonia in the tail gas is absorbed for a third stage, and the tail gas after third-stage absorption and replacement bypasses a demister and is discharged from the top of the absorption tower; ammonium sulfate mother liquor at the bottom of the absorption tower is conveyed to a crystallizing evaporator, concentrated mother liquor is evaporated firstly, and then is cooled down and crystallized, and separated to obtain ammonium sulfate. The method for treating low-concentration ammonia contained tail gas, which is provided by the invention, is suitable for producing solid ammonium sulfate in a small scale, and the ammonia content in the tail gas after treatment is lower than 10mg / Nm<3>.

Description

technical field [0001] The invention belongs to the field of environmental protection and relates to a method for treating low-concentration ammonia-containing tail gas, in particular to a method for treating low-concentration ammonia-containing tail gas and small-scale production and recovery of ammonium sulfate. Background technique [0002] Ammonia is one of the eight odorous pollutants stipulated by the Ministry of Environmental Protection. The odorous gas containing ammonia not only threatens human health, but also causes serious harm to the ecological environment. Common odor pollutant treatment technologies include adsorption, combustion, chemical absorption, and biological methods. With the continuous improvement of environmental protection requirements, how to recycle the production tail gas and unorganized exhaust gas in the production process of chemical plants has become one of the difficulties of many chemical production enterprises. Spraying with dilute sulfuri...

AI Technical Summary

Problems solved by technology

Both methods of treating ammonia-containing tail gas have their own difficulties: the water absorption method, according to the fact that ammonia gas is very soluble in water, when the temperature is 10°C under normal pressure, 1 volume of water can dissolve 700 times the volume of ammonia, but ammonia gas is soluble in Water will release a lot of heat, so that the temperature of the water will continue to rise with the continuous dissolution of ammonia gas, and the solubility of ammonia gas in water will also drop significantly, causing the ammonia gas originally dissolved in water to overflow again

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