660 MW煤粉锅炉掺烧生物质数值模拟  

Numerical simulation of co-firing characteristics of coal and biomass in a 660 MW boiler

作　　者：王俊 龙慎伟 马同胜 牛胜利[1] 王永征[1] 韩奎华[1] 路春美[1] WANG Jun;LONG Shenwei;MA Tongsheng;NIU Shengli;WANG Yongzheng;HAN Kuihua;LU Chunmei(School of Energy and Power Engineering,Shandong University,Jinan250061,China;Shandong Fengyuan Biomass Power Co.,Ltd.,Zaozhuang277300,China)

机构地区：[1]山东大学能源与动力工程学院,山东济南250061 [2]山东丰源生物质发电股份公司,山东枣庄277300

出　　处：《洁净煤技术》2022年第5期143-151,共9页Clean Coal Technology

基　　金：山东省重点研发计划资助项目(2019JZZY020305);山东大学青年学者计划资助项目(2015WLJH33)。

摘　　要：生物质作为可再生的碳中性能源,是化石能源的优良替代品,合理利用生物质能是我国实现“双碳”目标的重要途经。在现有生物质利用技术中,燃煤锅炉掺烧生物质不仅能减少化石燃料消耗及NO_(x)、SO_(2)等污染物排放,还能降低纯烧生物质导致的锅炉尾部受热面腐蚀风险,是提高能源利用率的有效措施。以660 MW煤粉锅炉为研究对象,基于Fluent数值模拟仿真软件对生物质与煤粉混燃过程进行研究,采用可实现湍流模型描述气相湍流,使用涡耗散模型计算挥发分燃烧,考察了生物质喷入位置和颗粒粒径对燃烧过程和NO_(x)排放的影响。计算结果表明,加入生物质对煤粉燃尽有一定促进作用,但NO_(x)排放降低。当生物质从最下层一次风喷口喷入时,能更早释放挥发分等有还原作用的成分,使得NO_(x)减排效果更好,炉膛出口烟气中NO_(x)质量浓度从原始工况的298.92 mg/m^(3)降至243.97 mg/m^(3),降低了18.4%。虽然生物质颗粒粒径变化对炉膛内烟气温度、O_(2)和CO体积分数影响较小,但颗粒粒径过大会导致生物质颗粒燃尽率降低,所需氧气减少,煤粉更易完全燃烧,出口烟气中NO_(x)质量浓度增大。As a renewable carbon-neutral energy,biomass is an excellent substitute for fossil energy.The rational utilization of biomass energy is an important way to achieve the "carbon peaking and carbon neutrality" goal in China.Among the various utilization technologies of biomass,co-firing biomass in coal-fired boilers can not only reduce the consumption of fossil fuels and the emissions of pollutants such as NO_(x) and SO_(2),but also reduce the risk of the corrosion of the boiler tail heating surface caused by pure burning of biomass,which is an effective measure to improve the efficiency of energy utilization.In this paper,the 660 MW pulverized coal boiler was taken as the research object,and the numerical simulation software Fluent was used to study the co-combustion process of biomass and pulverized coal,the realizable turbulence model was used to describe the gas-phase turbulence,the eddy dissipation model was used to calculate the combustion of volatiles,and the influences of biomass injection location and particle size on combustion process and nitrogen oxide emission were investigated.The calculation results show that the addition of biomass can promote the combustion of pulverized coal to a certain extent,whereas the NO_(x) emission is reduced.When biomass is injected from the primary air vent at the bottom layer,it can release the reducing components such as volatile matter earlier,so that the NO_(x)emission reduction effect is better.The NO_(x) mass concentration in the flue gas at the furnace outlet is reduced by 18.4% from 298.92 mg/m^(3) in the original working condition to 243.97 mg/m^(3).Although the change of biomass particle size has little effect on the flue gas temperature,O_(2) and CO volume fraction in the furnace,the excessive particle size will lead to the reduction of biomass particle burnout rate,thus reducing the required oxygen.As a result,the pulverized coal is easier to burn completely,and the NO_(x) mass concentration in the outlet flue gas increases.

关 键 词：燃煤锅炉 生物质 混燃 氮氧化物(NO_(x)) 燃煤污染物 

分 类 号：TK6[动力工程及工程热物理—生物能]