循环流化床锅炉SNCR+SCR联合脱硝流场优化研究
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摘要
采用CFD软件对某75 t/h燃煤型循环流化床锅炉SNCR+SCR联合脱硝的速度场、浓度场、温度场进行了数值模拟,比较了SCR部分优化前后的速度分布、浓度分布,并重点研究了SNCR部分还原剂喷入点的位置、喷射速度、喷雾粒径、喷雾锥角对SNCR脱硝的影响。结果表明:对该脱硝装置中的SCR部分进行优化时,可以仅对速度场进行优化而忽略对还原剂浓度场的优化;对于SNCR部分,还原剂喷入点设在进口段内侧优于外侧;增大喷射速度、增大雾化粒径均能增强还原剂与烟气的混合,有利于SNCR脱硝反应,而增大喷雾锥角对还原剂浓度分布的影响并不明显。
The velocity field,concentration field and temperature field of SNCR + SCR combined denitrification on a 75 t/h coal-fired CFB boiler were numerically simulated by CFD software. The velocity and concentration distribution were compared before and after optimization,and the effect of the location,injection speed,spray size and spray cone angle of reductant on SNCR denitrification efficiency at SCR part were studied. The results show that when we optimize the SCR part of this denitrification device,only the velocity field needs to be optimized,and the optimization on the concentration field could be ignored. For the SNCR part,the reductant injection point located at the inside of inlet section,increasing the spray velocity and increasing the atomized particle size can enhance the mixing of reductant and flue gas,which is beneficial to the SNCR denitrification reaction.The effect of increasing the spray cone angle on the concentration distribution of reductant is not obvious.
The velocity field,concentration field and temperature field of SNCR + SCR combined denitrification on a 75 t/h coal-fired CFB boiler were numerically simulated by CFD software. The velocity and concentration distribution were compared before and after optimization,and the effect of the location,injection speed,spray size and spray cone angle of reductant on SNCR denitrification efficiency at SCR part were studied. The results show that when we optimize the SCR part of this denitrification device,only the velocity field needs to be optimized,and the optimization on the concentration field could be ignored. For the SNCR part,the reductant injection point located at the inside of inlet section,increasing the spray velocity and increasing the atomized particle size can enhance the mixing of reductant and flue gas,which is beneficial to the SNCR denitrification reaction.The effect of increasing the spray cone angle on the concentration distribution of reductant is not obvious.
引文
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[12]Norbert Modliński.Numerical simulation of?SNCR?(selective non-catalytic reduction)process in coal fired grate boiler[J].Energy,2015,92(1):67-76.
[13]周强强.SCR脱硝系统烟道气动流场数值模拟研究[D].大连:大连海事大学,2015.
[2]陈国宁,曾祥朋.SNCR/SCR联合脱硝在燃煤锅炉上的模拟应用[J].环境科学与技术,2015,38(12Q):302-306.
[3]李竞岌,杨海瑞,李穹,等.循环流化床锅炉烟气脱硝系统优化模拟[J].中国电力,2013,46(9):1-5.
[4]赵永泉,赵宏岩,张光学.300 MW循环流化床锅炉SNCR试验及数值模拟[J].能源与环境,2015(4):40-43.
[5]王岳军,刘学炎,李世远,等.SNCR脱硝技术在循环流化床锅炉中的应用[J].环境工程.2013,31(1):59-62.
[6]周英贵.大型电站锅炉SNCR/SCR脱硝工艺试验研究、数值模拟及工程验证[D].南京:东南大学,2016.
[7]段传和,夏怀祥,谷小兵.燃煤电站SNCR脱硝系统喷射还原剂介质对锅炉效率的影响[J].电力科技与环保,2012,28(1):55-56.
[8]冯立波.燃煤电厂SCR反应器设计优化探讨[J].电力科技与环保,2016,32(2):12-14.
[9]Yuanyuan Xu,Yan Zhang,Fengna Liu,et al.CFD analysis on the catalyst layer breakage failure of an SCR-De NOxsystem for a350 MW coal-fired power plant[J].Computers and Chemical Engineering,2014(69):119-127.
[10]Yanhong Gao,Qingcai Liu,Lingtao Bian.Numerical Simulation and Optimization of Flow Field in the SCR Denitrification System on a 600 MW Capacity Units[J].Energy Procedia,2012(14):370-375.
[11]Zhizhong Kang,Qixin Yuan,Lizheng Zhao,et al.Study of the performance,simplification and characteristics of?SNCR?de-NOx in large-scale cyclone separator[J].Applied Thermal Engineering,2017(123):635-645.
[12]Norbert Modliński.Numerical simulation of?SNCR?(selective non-catalytic reduction)process in coal fired grate boiler[J].Energy,2015,92(1):67-76.
[13]周强强.SCR脱硝系统烟道气动流场数值模拟研究[D].大连:大连海事大学,2015.