Method for reducing ammonia escaping rate of flume denitration outlet

Abstract

The method of lowering the escapement rate of ammonia in the outlet of fume denitrator is to perform secondary treatment of denitrated fume before it enters to the air preheater. One molecular sieve reactor is set before the air preheater to eliminate unreacted ammonia completely or partially to lower the escapement rate of ammonia. The molecular sieve reactor is filled with elite, active carbon or artificially synthesized molecular sieve, and the molecular sieve has homogeneous pore size in 2.8-3.8 angstrom. The apparatus of the present invention can well control the escapement rate of ammonia, reduce the influence on the downstream apparatus, avoid secondary pollution, simplify the ammonia spaying set and its control system, and lower investment cost and running cost.

Description

technical field [0001] The invention relates to a process method and a device for reducing the escape rate of outlet ammonia in flue gas denitrification devices of coal-fired boilers, garbage incineration devices, diesel engines, gas turbines and other similar systems, and belongs to the technical field of environmental protection equipment. Background technique [0002] Nitrogen oxides in the exhaust exhaust of coal-fired boilers and similar devices are one of the main pollutants in the atmosphere. At present, the main control methods are selective non-catalytic reduction (SNCR), selective catalytic reduction (SCR) and SNCR / SCR combined process . The common point of these methods is that ammonia or urea is used as a reducing agent to react with nitrogen oxides in flue gas under the action of high temperature (SNCR process) or catalyst (SCR process) to generate harmless nitrogen and water discharge system. . In order to achieve the expected denitrification efficiency, vari...

AI Technical Summary

Problems solved by technology

However, due to the limitations of various conditions such as reaction conditions, contact time, and control accuracy, there will always be more or less ammonia that escapes without reaction.

This part of ammonia reacts with sulfur trioxide in the flue gas to form NH 4 HSO 4 , resulting in aggravated blockage, corrosion and dust accumulation of the downstream rotary preheater, and even affecting the normal operation of the entire device and system

Not only that, excessive ammonia escape will cause secondary pollution of the atmosphere, and ammonia combined in fly ash will affect the quality and saleability of fly ash

In order to reduce the harm of ammonia escape rate as much as possible, the method of reducing the denitrification efficiency or using more catalysts is usually adopted, which greatly affects the cost performance of the system

Images