摘要
为了研究再燃喷口竖直摆动角度对煤粉耦合生物质气再燃锅炉燃烧特性的影响,基于Fluent模拟软件搭建生物质气再燃锅炉模型,对某电厂600 MW燃煤锅炉耦合2台20 t/h秸秆气化炉再燃系统进行再燃喷口摆动角度分别为0°、±15°、±25°等5种工况燃烧过程进行数值模拟,分析燃烧区、折焰角及炉膛出口处烟气速度场及温度场分布特征。结果表明:生物质气再燃工况下炉内燃烧区温度变化趋势大致相同;改变再燃风喷口竖直摆动角度对炉内燃烧稳定性会造成影响;当再燃风喷口向下摆动角度过大(工况1)时,再燃风气流会扰动主燃区烟气气流,影响主燃区煤粉的燃烧;随着再燃喷口摆角向上倾斜,炉膛出口烟气温度偏差和温度分布不均匀系数M逐渐增大,再燃喷口摆角为+25°(工况4)时的M值最大,可达5.80%。在不影响炉内主燃区燃烧的同时,再燃喷口摆角为-15°时,炉膛出口烟气温度偏差最小。再燃喷口摆角向下倾斜一定角度,有利于减小炉膛出口热偏差。
In order to study the effect of the vertical swing angle of the re-burning nozzles on the combustion characteristics of a pulverized coal coupled biomass gas re-burning system,Based on Fluent simulation software to build a biomass gas reburning boiler model,a power plant 600 MW coal-fired boiler coupled with two 20 t/h straw gasifier re-burning systems was used to carry out numerical simulation of the combustion process in five cases including the swing angle of the re-burning nozzles is 0°,±15°,and±25°,respectively,analyze the distribution characteristics of the velocity field and temperature field of the flue gas at the combustion zone,the folding angle and the furnace outlet.The results show that the temperature change trend of the combustion zone in the furnace is roughly the same under the cases of biomass gas re-burning.Changing the vertical swing angle of the reburning air nozzle will affect the combustion stability in the furnace,when the downward swing angle of the reburning air nozzle is too large(case 1),the reburning air flow will disturb the flue gas flow in the main combustion zone and affect the combustion of pulverized coal in the main combustion zone.With the upward tilt of the re-burning nozzles swing angle,the flue gas temperature deviation at the furnace outlet and the uneven temperature distribution coefficient gradually increase,when the re-burning nozzles swing angle is+25°(case 4),the M value is the largest,reaching 5.80%.While not affecting the combustion of the main combustion zone in the furnace,when the re-burning nozzles swing angle is-15°,the flue gas temperature deviation at the furnace outlet is the smallest.The swing angle of the reburning nozzle is inclined downward to a certain angle,which is beneficial to reduce the thermal deviation of the furnace outlet.
作者
张小桃
张卫东
张程俞
慕昊良
刘昊明
王爱军
ZHANG Xiaotao;ZHANG Weidong;ZHANG Chengyu;MU Haoliang;LIU Haoming;WANG Aijun(North China University of Water Resources and Electric Power,Zhengzhou 450045,China)
出处
《能源研究与管理》
2021年第1期50-56,62,共8页
Energy Research and Management
基金
河南省高等学校重点科研项目“基于再燃技术的燃煤锅炉耦合生物质气系统特性研究”(21A480006)。
关键词
生物质气再燃
摆动角度
数值模拟
热偏差
biomass gas re-burning
swing angle
numerical simulation
thermal deviation
