Method for treating NOx waste gas in preparation process of molecular sieve catalyst

Abstract

The invention discloses a method for treating NOx waste gas in a preparation process of a molecular sieve catalyst. The method comprises the following steps: 1) introducing an absorbent: introducing the absorbent in a liquid storage tank into a supergravity reactor through a liquid phase inlet of the supergravity reactor, with the absorbent formed by mixing urea and an oxidizing agent; 2) removingNOx: introducing the NOx waste gas generated in the preparation process of the molecular sieve catalyst into the supergravity reactor from a gas phase inlet of the supergravity reactor through a NOxwaste gas exhaust port, and bringing the NOx waste gas into full contact with the absorbent to remove NOx in the NOx waste gas; (3) after NOx is removed, discharging the gas with NOx removed through agas phase outlet of the supergravity reactor, and discharging the absorbent into the liquid storage tank through a liquid phase outlet of the supergravity reactor. The method provided by the invention has the advantages of high NOx removal efficiency, simple steps and low cost, and is suitable for large-scale industrial application; the invention belongs to the technical field of waste gas treatment.

Description

technical field [0001] The invention belongs to the technical field of exhaust gas treatment, in particular to a kind of NO x Waste gas treatment methods. Background technique [0002] The preparation of molecular sieve catalyst mainly includes pulping, crystallization, drying, primary roasting, ammonium exchange and secondary roasting and other main processes. Among them, the primary roasting is the process of roasting the dried molecular sieve at high temperature in the air to decompose the organic template agent, in which the template agent is mostly a nitrogen-containing compound, which is oxidized into NO during the roasting process. x ; Secondary roasting is to ammonia molecular sieve (NH 4 + ) high-temperature roasting to become active hydrogen-type molecular sieves (H + ) process, NH 4 + removal will also generate NO x . A large amount of waste gas will be generated during the two roasting processes, and the flow rate of the roasting waste gas can reach 100,0...

AI Technical Summary

Problems solved by technology

A lot of research work has been done on the reaction mechanism of SCR and the selection of catalysts at home and abroad. NO x The removal rate of SNCR can reach more than 90%, but its disadvantage is that the investment and operation cost is high, the catalyst needs to be used, and the catalyst is easily poisoned; although SNCR has the advantages of not needing a catalyst and low operating cost, its disadvantage is that the NO x The removal rate is low, the reaction requires a higher temperature (800-1000°C), and the energy consumption is high

[0004] In order to solve the problem of NO x NO in exhaust gas x For the problems of low removal efficiency, high energy consumption, high cost, and the need to use catalysts, someone proposed an ozone oxidation flue gas denitrification device, which includes an oxidation part and a wet absorption part, wherein the oxidation part includes ozone Generator and oxidation reactor, the wet absorption part includes the absorption tower and the sprayer and demister in the absorption tower, although the device is effective for NO x The exhaust gas removal efficiency is high, but the ozone generator consumes high energy and costs, and the discharge from the lye pool contains a large amount of nitrate, which requires secondary treatment and the process is complicated

Others have proposed a method for removing industrial tail gas NO with a complexing agent solution as an absorbent and using a high-gravity rotating bed as a reactor. x The removal efficiency of exhaust gas reaches more than 90%, and the treatment process is relatively simple, but the reaction product is easy to cause secondary pollution, and the investment cost is high, so it is not suitable for large-scale industrial application

In addition, for NO in the preparation process of molecular sieve catalyst x There is no targeted research report on the treatment method of exhaust gas

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