SNCR and low-temperature SCR coupled flue gas denitration system and use method thereof

Abstract

The invention discloses an SNCR and low-temperature SCR coupled flue gas denitration system and a use method thereof. The system comprises a tail flue, a flue gas heater, a low-temperature SCR reactor, a main spray gun and an ammonia water tank, wherein the main spray gun is connected with an outlet of the ammonia water tank through a ammonia water pump, the main spray gun is arranged in a front flue of the tail flue, the main spray gun is used for spraying ammonia water into the front flue and performing an SNCR reaction, a flue gas outlet of the tail flue is connected with a flue gas inlet of the flue gas heater, a flue gas outlet of the flue gas heater is connected with a flue gas inlet of the low-temperature SCR reactor, and the low-temperature SCR reactor is used for carrying out low-temperature SCR reaction by taking escape ammonia in the SNCR reaction as a denitration reducing agent. The SNCR and low-temperature SCR processes are coupled for denitration at a relatively low fluegas temperature, so that NOx emission under all working conditions reaches the standard; and the denitration cost can be saved, certain flexibility and reliability are achieved, and the system is simple in device, small in boiler body transformation amount and easy to popularize.

Description

technical field [0001] The invention belongs to the technical field of air pollution control and environmental protection, and in particular relates to a flue gas denitrification system coupled with SNCR and low-temperature SCR and a use method thereof. Background technique [0002] With the improvement of our country's economy and living standards, people will pay more and more attention to the environment. The environmental pollution caused by coal-based industrial production is a restrictive factor for my country's industrial development. The tail gas produced by coal combustion contains soot, sulfur dioxide (SO 2 ), nitrogen oxides (NO x ) and carbon dioxide (CO 2 ) and other pollutants and greenhouse gases have caused serious environmental problems, which are important issues to be solved urgently for the sustainable development of my country's economy. At present, coal-fired boilers in power stations, boilers burning domestic waste, and industrial boilers / kilns are ...

AI Technical Summary

Problems solved by technology

The SNCR process system is simple and the investment cost is low, but subject to the reaction conditions, the denitrification efficiency is low; the SCR denitrification process has high denitrification efficiency but the system is complicated and the investment cost is high, and when it is applied to the old boiler renovation, it is often due to the SCR reaction temperature conditions and layout. Due to problems such as insufficient space, it is necessary to renovate the heating surface and flue at the tail of the boiler. When the NOx concentration meets the environmental protection standard and realizes ultra-low emission, it is necessary to invent new technical means

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