Selective non-catalytic reduction denitration system of circulating fluidized bed boiler

Abstract

The invention discloses a selective non-catalytic reduction denitration system of a circulating fluidized bed boiler, belonging to the technology of flue gas denitration. The system comprises a hearth, a reducing agent and atomization air proportion conveying system, a cyclone separator, a material return system and a tail flue, and is characterized in that: multiple atomization nozzles are uniformly arranged on the upper top plate of the separator on the periphery of a core cylinder of the cyclone separator; the openings of the atomization nozzles face downwards; and an angle of 0-60 degrees is formed between the reducing agent spraying direction and the vertical direction. According to the invention, by adopting reasonable spraying position and angle and nozzle number for the selective non-catalytic reducing agent, the mixing degree of the reducing agent and NOx in flue gas is increased, the denitration reaction is promoted, the efficiency and feasibility of the selective non-catalytic reduction denitration are improved, the leakage of the reducing agent is reduced, and the industrial application of the selective non-catalytic reduction denitration method is facilitated.

Description

technical field [0001] The invention relates to a selective non-catalytic reduction (SNCR) denitrification system applied to a circulating fluidized bed boiler, belonging to flue gas denitrification technology. Background technique [0002] Nitrogen oxides (NOx) are the three major pollutants emitted by coal-fired power plants (SO 2 , one of NOx and total suspended particulate matter (TSP). With the increasingly stringent national and local environmental protection policies, flue gas denitrification technology has received more and more attention. [0003] Currently, the commonly used flue gas denitrification technologies include selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). Selective Catalytic Reduction (SCR) is the use of reducing agents (ammonia, urea, etc.) to reduce NOx to N under the action of a catalyst 2 Technology. SCR has the advantages of high efficiency and low leakage rate, but it also has obvious disadvantages, such as hi...

AI Technical Summary

Problems solved by technology

When the injection position is at the inlet, such as US Patent No. 5462718 and 11 / 747010, the reducing agent nozzle is at an angle of 90° to the cyclone separator inlet. Since the flue gas at this position contains a large number of particles, it is easy to cause the reducing agent nozzle to wear and nozzle clogging affect the effect of reducing agent injection

When the injection position is at the outlet, such as U.S. Patent 6325985, because the cyclone separator has the best reaction conditions for SNCR reaction, this type of design does not use the method of injecting the reducing agent into the separator, and the denitrification effect is not obvious

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