Method for treating high-concentration ammonia nitrogen in chemical waste gas

Abstract

The invention discloses a method for treating high-concentration ammonia nitrogen in chemical waste gas. The method includes the steps: firstly, placing the chemical waste gas in an absorption tower and absorbing the chemical waste gas by orthophosphoric acid to generate diammonium hydrogen phosphate and ammonium dihydrogen phosphate mixed solution; secondly, continuously circulating the solution by a lift pump and repeatedly absorbing ammonia until diammonium hydrogen phosphate is completely generated; thirdly, introducing the generated diammonium hydrogen phosphate into an ammonia still containing Pd-Zn-Hg-Cr As-V / titanium dioxide catalysts through a pipeline and adding an organic denitrifying agent comprising polyvinyl acetate, trifluoromethyl benzoic acid and methylbenzyl alcohol; and fourthly, introducing steam into the ammonia still and decomposing the diammonium hydrogen phosphate into ammonium dihydrogen phosphate and nitrogen under the action of the organic denitrifying agent and the catalysts. Phosphoric acid is used as an absorbent for absorbing ammonia in waste gas without adjusting pH (potential of hydrogen) value, and secondary pollution is avoided as decomposition of the diammonium hydrogen phosphate is promoted by adding the organic denitrifying agent and the diammonium hydrogen phosphate is completely converted into nitrogen to be exhausted under the catalytic action of the catalysts. Besides, the generated ammonium dihydrogen phosphate can also be used as an absorbent for reabsorbing the ammonia, so that the absorbent can be recycled.

Description

technical field [0001] The invention relates to a method for treating high-concentration ammonia nitrogen in chemical waste gas, belonging to the field of waste gas treatment. Background technique [0002] With the development of the economy, heavy industries such as petroleum and chemical industry have developed rapidly, and chemical companies have sprung up like mushrooms in various places, and the air pollution problem that follows has become more and more serious. The composition of the exhaust gas is complex, the pollution is wide, the hazard is great, and it is difficult to control. In addition, air pollutants will also fall into the water body, soil and crops through various ways to affect the environment, and through breathing, skin contact, food, Drinking water enters the human body, causing harm to human health and the ecological environment. Therefore, it is imperative to carry out advanced treatment of chemical waste gas. [0003] At present, the removal method...

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Problems solved by technology

[0006] The present invention aims at the deficiencies of the above technologies, and provides a method for absorbing the ammonia nitrogen in the exhaust gas by using phosphoric acid as the absorption punishment, not only without adjusting the pH value, but also because the addition of the organic denitrification agent promotes the decomposition of diammonium hydrogen phosphate, And under the catalysis of the catalyst, it is completely converted into nitrogen emission, which avoids the problem of secondary pollution. In addition, the generated ammonium dihydrogen phosphate can be used as an absorbent to reabsorb ammonia, which can be recycled.