SNCR denitrification system and denitrification method

Abstract

The invention discloses an SNCR denitrification system and a denitrification method. The SNCR denitrification system comprises a first nozzle group arranged in the middle-upper part of a furnace hearth and/or a second nozzle group arranged on the connection flue, and an ammonia liquid tank and a mixing vaporizer. The mixing vaporizer comprises an ammonia liquid pipe, a steam pipe, a venturi mixingpipe and a vaporizing pipe. A three-way structure is formed between the ammonia liquid pipe, the steam pipe and the vaporizing pipe. The nozzle adopts a sleeve structure, including a denitrifying agent inner tube and a cooling sleeve, and the front end of the denitrifying agent inner tube is provided with a venturi atomizing tube and a nozzle is arranged at the outlet end of the venturi atomizingtube. A steam with pressure is introduced into the mixing vaporizer through a steam pipe, and a negative pressure is formed when that steam passes through the venturi vaporization pipe, so that a denitrifying agent in the ammonia liquid tank is sucked into the venturi vaporization pipe from the ammonia liquid pipe under the negative pressure; the denitrifying agent and steam are mixed and heat isexchanged in the venturi vaporizing pipe, so that the denitrifying agent is vaporized. The denitrifying agent steam is sent from the vaporizing pipe to the spray pipe and sprayed into the flue gas toremove NOx from the flue gas. The invention has the advantages of good ammonia liquid mixing and atomizing effect, high denitrification efficiency and the like.

Description

technical field [0001] The invention relates to an efficient SNCR denitration system and a denitration method, belonging to the technical field of combustion flue gas treatment. Background technique [0002] Nitrogen oxides (NOx) are one of the main pollutants in the atmosphere. In my country, fossil fuels account for a high proportion of primary energy consumption. As the public's awareness of environmental protection increases, the requirements for NOx emissions in flue gas are becoming more and more stringent. In order to meet the increasingly stringent emission standards, most coal-fired flue gas denitrification adopts SNCR-SCR combined denitrification system. SNCR (Selective Non-Catalytic Reduction) does not use a catalyst, which can save investment to a certain extent, but it needs to be set in the high temperature section. SCR (Selective Catalytic Reduction) uses a catalyst and has high efficiency, but the operating cost is high due to the need to update the cataly...

AI Technical Summary

Problems solved by technology

SCR (Selective Catalytic Reduction) uses a catalyst and has high efficiency, but the operating cost is high due to the need to update the catalyst

The reason why SNCR and SCR are often used in combination is mainly due to the low NOx removal efficiency of SNCR and the high ammonia slip

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