Low-consumption and low-emission nitric acid production method and production equipment thereof

Abstract

The invention discloses a low-consumption and low-emission nitric acid production method and production equipment thereof. The method and the equipment adopts the same low-pressure level for oxidation and absorption, the double-pressurization high-pressure level is omitted, a molecular sieve absorption device is adopted for tail gas treatment of a nitric acid absorption tower, in addition, secondary air is used for taking reaction with nitric oxide absorbed in the molecular sieve absorption device to form regenerated gas, the regenerated gas is sent into the nitric acid absorption tower to be recovered and reutilized, the nitrogen oxide content in the tail gas is lower than 100mg / Nm<3>, in addition, the yield of the nitric acid can also be improved through the recovery and the utilization of regeneration gas, a layer of silk screen is arranged on a sieve plate tower disc of an oxidation section of the nitric acid absorption tower, the oxidation speed at high pressure and low pressure can be effectively accelerated, and an N20 decomposition catalyst layer is also additionally arranged in an oxidation reaction vessel, so the N20 content in the nitric oxide gas in the oxidation reaction vessel can be reduced to about 100PPM. The nitric acid production method does not need to adopt two pressure levels, no nitric oxide compressor is adopted, no tail gas ammonification re-treatment device is adopted, the investment is greatly saved, and the consumption is reduced.

Description

technical field [0001] The invention relates to the technical field of producing nitric acid, in particular to a method for producing nitric acid by using ammonia and air and production equipment thereof. Background technique [0002] At present, the new processes of producing nitric acid with ammonia and air at home and abroad include normal pressure method (that is, the oxidation pressure and absorption pressure are normal pressure), medium pressure method (that is, the oxidation pressure and absorption pressure are 0.3 to 0.4 Mpa) and high pressure method (that is, The oxidation pressure and absorption pressure are 1.0 to 1.2 Mpa,), while the most advanced nitric acid production process belongs to the double pressure method, that is, the oxidation pressure is 0.4 to 0.5 Mpa, and the absorption pressure is 1.0 to 1.2 Mpa, which can make the oxidation The consumption of platinum is lower, and the purpose of nitrogen oxides in tailpipe emissions is also lower. The main prob...

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Problems solved by technology

[0004] (2), the nitrogen oxides emitted from the tail gas are 400mg / Nm 3 , not reaching the national 300 mg / Nm 3 , emission index;

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