1000MW锅炉SCR烟气脱硝系统的数值模拟及优化

发布时间：2018-03-14 22:15

本文选题：SCR　切入点：数值计算　出处：《华北电力大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,我国电力工业发展迅速,促进了经济的高速增长,同时也造成了越来越严重的环境污染,特别是氮氧化合物的排放与日俱增。选择性催化还原(SCR)烟气脱硝技术具有脱硝效率高,技术成熟可靠等优势,越来越多的电厂采用该技术。本文结合某1000MW机组锅炉SCR烟气脱硝系统,根据传热传质的相关理论,利用数值计算软件Fluent对该系统进行了数值模拟。首先,应用Gambit软件建立了该系统的三维实体模型,再应用Fluent软件计算了有无导流装置时,SCR系统的烟气流动情况。计算结果表明,安装适当的导流板能够改善烟气流动的均匀性,减少烟气回流的发生,进而提高催化还原反应的速率。为了提高氨气摄入量的控制精度,改善烟气与氨气混合的均匀性,对喷氨格栅的控制结构进行了改造,增加阀门数量,从而减少单个阀门的控制区域,同时结合Fluent模拟结果,对每个阀门开度进行合理控制,使氨气和烟气按照合理的比例充分混合,提高了反应效率,降低了氨逃逸率。通过对该电厂的合理改造,通过性能试验,取得了较好的结果,验证了模拟计算和改造的合理性。
[Abstract]:In recent years, China's electric power industry has developed rapidly, which has promoted the rapid growth of the economy, and at the same time has caused more and more serious environmental pollution. In particular, the emission of nitrogen and oxygen compounds is increasing. The selective catalytic reduction (SCR) flue gas denitrification technology has the advantages of high denitrification efficiency, mature and reliable technology, etc. More and more power plants adopt this technology. In this paper, the SCR flue gas denitrification system of a 1000MW unit boiler is numerically simulated by using the numerical calculation software Fluent, according to the theory of heat and mass transfer. The three-dimensional solid model of the system is established by using Gambit software, and the flue gas flow of the system with or without diversion device is calculated by using Fluent software. The calculation results show that the uniformity of flue gas flow can be improved by installing appropriate guide plate. In order to improve the control accuracy of ammonia intake and improve the uniformity of the mixture of ammonia gas and flue gas, the control structure of ammonia spray grille was modified to increase the number of valves, so as to reduce the occurrence of flue gas reflux and increase the rate of catalytic reduction reaction. In order to reduce the control area of a single valve, combined with the Fluent simulation results, the opening of each valve is controlled reasonably, so that ammonia gas and flue gas are fully mixed in a reasonable proportion, and the reaction efficiency is improved. The ammonia escape rate is reduced. Through the reasonable transformation of the power plant and the performance test, good results are obtained, and the rationality of the simulation calculation and transformation is verified.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621.2

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