Nitrogen oxide tail gas absorption solution and method for preparing powdered nitric acid with absorption solution

Abstract

The invention discloses nitrogen oxide tail gas absorption solution which comprises the following components by weight percentage: 10-20% of urea, 3-15% of hydrochloric acid, 3-20% of nitric acid, and the balance of water. The invention further discloses a method for preparing powdered nitric acid with the nitrogen oxide tail gas absorption solution. The method comprises the steps that nitrogen oxide tail gas is supplied to a buffer tank filled with distilled water for cooling, initial absorption and tail gas flow velocity buffer; the nitrogen oxide tail gas is introduced into an absorption tower for multistage absorption; the temperature of the absorption solution is controlled at 15-25 DEG C; when urea nitrate is crystallized in the absorption solution, the absorption solution is frozen to be below 10 DEG C; a urea nitrate crystal (the powered nitric acid) is separated by crystallization; and a mother solution is recycled after consumed urea is supplemented and water volume is shifted. The nitrogen oxide tail gas absorption solution and the method have the advantages that the absorption efficiency of the nitrogen oxide tail gas is high, the urea consumption is small, the absorption solution can be recycled; the environmental protection management cost is low; powdered nitric acid is synthesized by the nitrogen oxide tail gas absorption solution; the production cost of powdered nitric acid is lowered; and the environmental pollution of the nitrogen oxide tail gas is solved.

Description

Technical field [0001] The invention relates to a nitrogen oxide tail gas absorption liquid, in particular to a nitrogen oxide tail gas absorption liquid containing hydrochloric acid, nitric acid and urea. The invention also relates to a method for preparing powder nitric acid by using the nitrogen oxide tail gas absorption liquid, which belongs to the fields of petrochemical industry and environmental protection. Background technique [0002] Nitric acid is a very important chemical product, but it is a highly corrosive, highly oxidizing and volatile liquid acid, which has many inconveniences in transportation, storage and use. In practical applications, it is hoped that it is in solid form. At present, a kind of powdered nitric acid is sold on the market. Its chemical composition is actually urea nitrate, which is obtained by reacting nitric acid and urea in an equimolar ratio. The theoretical content of nitric acid in the product is 51.2%. Contains about 10% moisture. Urea n...

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Problems solved by technology

[0008] The purpose of the present invention is to provide a nitrogen oxide tail gas absorption liquid to improve the absorption efficiency of nitrogen oxide tail gas and solve the problem of tail gas pollution in the process of producing glyoxylic acid by nitric acid oxidation