Effect of Cement Raw Material and Oxygen Concentration on SNCR Reaction

Abstract:

As the selective non-catalytic reduction denitration(SNCR denitration) was used in cement decomposition furnaces under the high concentration cement raw materials and complex flue gas composition , the denitration efficiency is poor and the reducing agent is largely consumed.In order to meet the more stricter requirements of environmental protection, there is an urgent need to improve the denitration efficiency of SNCR and reduce the escape of reducing agentsin order to prevent the unnecessary waste caused by excessive use of reducing agents and secondary atmospheric pollution.Therefore, studying the effect of cement raw materials and O₂ concentration on SNCR process is very important. In this paper, the initial concentration of NO and the ammonium to nitrogen ration (C_NH3/C_NO) was 800ppm and 1.5, respectively. The effects of cement raw material and oxygen concentration on the reaction process of NH₃+NO+O₂ in the temperature range of 750°C -1100°C were investigated by means of denitration rate, in Situ DRIFTS analysis.The results demonstrate when O₂ concentration was 5% and denitration temperature was 950°C, the deNOx rate reached a maximum of 89.64%, which due to O₂ promoted NH₃ and NO to react with O₂ to produce N₂ and H₂O. However,under the effect of cement raw material, O₂ can promote NH₃ which was adsorbed on the surface of cement raw material to react with O₂ and produce NO and H₂O, and the reaction of oxidation of NH₃ is dominant, therefore, the denitration reaction is inhibited. .When O₂ concentration was 5% and temperature was 850°C, the deNOx rate reached a minimum value of -109.09%. the high concentration cement raw material and flue gas composition reduce the denitration efficiency of cement kiln.

• Periodical: Materials Science Forum (Volume 913)
• Pages: 969-975
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.913.969
• Online since: February 2018
• Authors: Ya Li Wang*, Nan Li, Si Yu Peng, Yun Ning Zhang, Mei Na Chen, Su Ping Cui
• Keywords: Cement Raw Materials, deNOx Rate, Oxygen Concentration, Selective Non-Catalytic Reduction

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