A DAMK(O)HLER NUMBER FOR EVALUATING COMBUSTION EFFICIENCY OF HORIZONTAL CIRCULATING FLUIDIZED BED BOILERS
The combustion efficiency of typical circulating fluidized bed (CFB) boilers with small capacity unit is usually lower than expected, due to the high carbon content in the fly ash.Novel horizontal circulating fluidized bed (HCFB) boilers, which consist of three relatively lower furnaces horizontally connected in series and two-stage separators in tandem have been proposed.In order to evaluating combustion efficiency of HCFB boiler, a dimensionless criteria —Damk(o)hler number, Da, which is the ratio of char particle total residence time in the furnace to char burnout time, is proposed.Numerical results show that Da of HCFB boiler is much larger than that of CFB boiler with same furnace height, which indicates higher combustion efficiency in HCFB boiler.Further analysis infers that higher combustion efficiency of HCFB boiler is mainly due to its two-stage separators arranged in series.Combination of initial U-turn separator and secondary cyclone separator results in a higher total fractional separation efficiency, which greatly improves particle residence time especially for char particles ranging from 50 to 100 μm.The Da could provide a comprehensive guide to HCFB boiler design and operation optimization.
Feng Heng Li Qinghai Meng Aihong Zhang Yanguo
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Beijing Key Laboratory for CO2 Utilization and Reduction Technology,Department of Thermal Engineering,Tsinghua University,Beijing 100084,China
国际会议
The 11th International Conference on Fluidized Bed Technology(CFB-11)(第十一届流化床技术国际会议)
北京
英文
613-618
2014-05-14（万方平台首次上网日期，不代表论文的发表时间）