Process and device for treating nitric oxide in tail gas generated in nitric acid and nitrate production

Abstract

The invention discloses a process and a device for treating nitric oxide in tail gas generated in the nitric acid and nitrate production. The process comprises the following steps: (1) carrying out tempering reaction on the tail gas generated in the the nitric acid and nitrate production by virtue of a 30-68% nitric acid solution, and controlling the volume percentage of NO to NO2 in the tempered tail gas to be 0.95-1.05; and (2) carrying out absorption reaction on the tempered tail gas by virtue of an alkaline absorption liquid, so as to generate nitrate and nitrite. The device comprises an absorption tower which comprises an oxidized-nitric-acid circulating storage tank, a tail gas tempering region, an alkali absorption region and a demisting region from bottom to top, wherein the tail gas tempering region and the alkali absorption region are separated by a tower board, air hoods are uniformly distributed on the tower board, a tail gas inlet is formed in the lower end of the tail gas tempering region, and a tail gas outlet is formed above the demisting region. The process and the device have the advantages that the efficiency is high, the cost is low, the nitric oxide in the tail gas can be recycled, and the tail gas processed by virtue of the process and the device can meet an emission requirement of 'emission standard of pollutants for nitric acid industry'.

Description

technical field [0001] The invention relates to a process and a device for treating nitrogen oxides in tail gas produced by nitric acid and nitrate (two sodium), and belongs to the technical field of air pollution control. Background technique [0002] In the nitric acid industry, nitric acid production and nitrate (two sodium) production are divided into different processes such as normal pressure method, medium pressure method, high pressure method and double pressure method. The NO in the tail gas produced by each production process is X concentrations are also different. NO in the tail gas of normal pressure method and medium pressure method X The content of the total NO in the tail gas of the high-pressure method and the double-pressurization method X concentration is relatively low. Starting from March 1, 2011, the air pollutant emission standards for nitric acid industrial enterprises will be implemented: "Emission Standards for Nitric Acid Industrial Pollutants" (...

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Problems solved by technology

[0007] Based on the above present situation, the object of the present invention is to overcome the low efficiency of the absorption method and the high investment of other treatment methods, and propose a treatment process for nitrogen oxides in the tail gas of nitric acid and nitrate production. The efficiency of the process is high, and the tail gas passes through the present invention The treatment of the process can meet the emission requirements of the "Nitric Acid Industrial Pollutant Discharge Standard" (GB26131-2011)

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