摘要
为与复杂实际流动模型结合并适应炉膛燃烧模拟计算,需要建立简化的能准确反映NO还原过程的SNCR总包反应动力学模型。不同于实验数据直接拟合方法,采用遗传算法,通过比较总包反应模型与详细机理模型的计算结果,得到了优化的总包反应动力学参数。在不同反应停留时间、不同NSR和不同温度(800~1 400 K)下利用总包反应动力学模型进行计算。结果表明:总包反应模型能够准确预测NO还原反应温度窗口、脱硝效率和氨的摩尔分数的变化规律,也能够预测停留时间和NSR对脱硝效率及氨逃逸的影响,具有较好的适用性;预测停留时间为0.3 s时最低NO摩尔分数出现在1 225 K的温度下,最佳脱硝效率约为80%;当温度为1 193 K且氨氮比为1.5、反应时间为0.1 s左右时,反应体系中NO物质的量浓度就已降为初始浓度的50%以下;当反应时间延长到0.6 s时,脱硝率几乎达到最大值,停留时间超过0.6 s之后NO摩尔分数降低不明显。
In order to combine with the complex flow model and adapt to the furnace combustion simulation,it is necessary to establish a simplified SNCR overall reaction kinetic model which can accurately reflect the NO reduction process.Different from the method of directly fitting the experimental data,this work adopts the genetic algorithm to obtain the optimized kinetic parameters of the overall reactions by comparing the calculated results of the overall reaction model and the detailed mechanism model.Under the conditions of different residence times,NSRs and different temperatures(800 K to 1 400 K),the overall reaction kinetic model was used to calculate the NO reduction.The results showed that the overall reaction model can accurately predict the temperature window,denitrification efficiency and the changes in ammonia mole fraction of NO reduction reaction,and it can also predict the effect of residence time and NSR on the denitrification efficiency and ammonia escape,which indicates the good applicability of the established overall reaction model.Among them,it was successfully predicted that the lowest NO mole fraction appeared at the temperature of 1 225 K when the residence time was 0.3 s,and the optimal denitration efficiency was about 80%.When the temperature is 1 193 K,the ammonia nitrogen ratio is 1.5,and the reaction time is about 0.1 s,the molarity concentration of NO in the reaction system has decreased to less than 50% of the initial concentration.When the reaction time is extended to 0.6 s,the denitration almost reaches the maximum value,and further extension after the residence time exceeding 0.6 s has no significant effect on the reduction of NO mole fraction.
作者
张曜
于娟
姜金东
张忠孝
ZHANG Yao;YU Juan;JIANG Jin-dong;ZHANG Zhong-xiao(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai,China,200240)
出处
《热能动力工程》
CAS
CSCD
北大核心
2021年第1期87-92,共6页
Journal of Engineering for Thermal Energy and Power
基金
国家重点研发计划(2016YFB0600202)。
关键词
总包反应
动力学模型
脱硝
NO还原
overall reaction
kinetic model
denitrification
NO reduction
