摘要
为有效利用燃机排烟热量,探索燃煤锅炉与燃机烟气耦合燃烧可行性。根据燃烧学基本理论,分析燃机烟气混入对燃煤锅炉的燃烧理论空气量、烟气量、燃烧器喷口速度等参数影响,提出燃机烟气与燃煤锅炉耦合燃烧技术方案。运用全尺寸数值模拟技术,分析烟气耦合对燃煤锅炉燃烧特性影响。数值模拟结果表明,烟气耦合后燃煤锅炉火焰切圆直径变大;煤粉气流初始温度增加,挥发分析出提前,煤粉着火提前;燃煤锅炉烟气量增大,锅炉炉膛温度降低,水冷壁吸热量下降;炉膛出口NOx排放质量浓度由222.1 mg/m^(3)升至229.5 mg/m^(3),焦炭燃尽率由98.91%降至96.9%。结合数值模拟结果,分析烟气耦合后发电机组能耗。虽然机组发电煤耗较耦合前升高2.0 g/kWh,但燃机烟气的余热利用效率由约80%提升至约93%,折算机组煤耗降低10.98 g/kWh,全厂能耗降低8.98 g/kWh,表明燃机烟气与燃煤锅炉耦合燃烧技术方案可行。燃机烟气替代了大部分燃煤锅炉二次风量,通过燃煤锅炉空预器的风量大幅降低,造成空预器换热量大幅下降,排烟温度大幅升高,需在空预器后增加余热利用装置。
To effectively utilize the exhaust heat of gas turbines,the feasibility of coupling combustion technology of coal-fired boilers and gas turbines flue gas was explored.Based on the basic theory of combustion,detailed calculations were conducted on the theoretical air volume,flue gas volume,burner nozzle velocity and other parameters of coal-fired boiler combustion after mixing with gas turbine flue gas.A coupling combustion technology scheme of gas turbine flue gas and coal-fired boiler was proposed.The influence of flue gas coupling on the combustion characteristics of coal-fired boiler was analyzed using full-scale numerical simulation technology.The nu-merical simulation results indicate that after flue gas coupling,the tangential diameter increases.As the initial temperature of pulver-ized coal flow increases,the volatile releases earlier,and the pulverized coal ignites earlier,the temperature of the boiler furnace decrea-ses,and the heat absorption of the water wall decreases.The NOx emission at the furnace outlet increases from 222.1 mg/m^(3) to 229.5 mg/m^(3),and the burnout rate decreases from 98.91%to 96.9%.Based on numerical simulation results,the energy consumption of the whole plant after flue gas coupling was analyzed,it can be concluded that although the coal consumption of boiler power generation in-creases by 2.0 g/kWh,the waste heat utilization efficiency of gas turbine flue gas has increased from about 80%to about 93%,represen-ting a reduction of 10.98 g/kWh in the coal consumption of boiler power generation,so the energy consumption of the whole plant has de-creased.The results indicate that coupling combustion technology of coal-fired boilers and gas turbines is feasible.After flue gas coupling,the gas turbine flue gas replaces most of the secondary air,significantly reducing the air flow through the air preheater,resulting in a sig-nificant decrease in the heat of the air preheater and a significant increase in the flue gas temperature.It is necessary to add a waste heat utilization device aft
作者
赖金平
陈辉
张文振
刘欣
李朝兵
何陆灿
葛铭
LAI Jinping;CHEN Hui;ZHANG Wenzheng;LIU Xin;LI Chaobing;HE Lucan;GE Ming(Guoneng Nanjing Electric Power Test&Research Limited,Nanjing210031,China;Yantai Longyuan Electric Power Technology Co.,Ltd.,Yantai264006,China)
出处
《洁净煤技术》
CAS
CSCD
北大核心
2024年第7期120-126,共7页
Clean Coal Technology
基金
国家能源集团科学技术研究院有限公司科技资助项目(DY2022Y05)。
关键词
燃机烟气
燃煤锅炉
耦合
燃烧特性
余热效率
gas turbines flue gas
coal-fired boiler
coupling
combustion characteristics
waste heat efficiency
