The size distribution of coal particles in a Circulating Fluidized Bed (CFB) boiler plays a crucial role in the complicated combustion, heat exchange and pollutant emissions in such a plat. Therefore, it is fundamenta...The size distribution of coal particles in a Circulating Fluidized Bed (CFB) boiler plays a crucial role in the complicated combustion, heat exchange and pollutant emissions in such a plat. Therefore, it is fundamental to study the different factors having influence on the size distribution of coal particles. Above all, the coal itself and in particular, the coal combination phenomenon is a very influent factor. In the frame of this work, the coal nature (elementary composition) and coal internal structure (mineral components) are studied in detail. At this intermediary stage, experiments on three typical Chinese coals on a l.5 MWt CFBC pilot plant have been made. Some primary fragmentation tests have also been made in a small lab scale fluidized bed reactor. The results from the hot pilot test show i) the variation of coal ash distributions and other CFB performance data due to the cyclone and the coal characteristics and ii) the variation of desulfurization efficiency with limestone. Whereas the bench scale primary fragmentation test, likely linked to the caking propriety of a coal, does not seem to change considerably the char size distribution.展开更多
In this paper,the combustion process of oil shale semicoke was investigated by modeling,where intraparticle mass transfer resistance was especially considered.The ash formation and attrition characteristics of oil sha...In this paper,the combustion process of oil shale semicoke was investigated by modeling,where intraparticle mass transfer resistance was especially considered.The ash formation and attrition characteristics of oil shale semicoke were also investigated by a laboratory test procedure.The burnout time and residence time of different particle sizes were predicted,and the maximum particle size of which oil shale semicoke could be burned out in a 3 MW circulating fluidized bed boiler was obtained.展开更多
文摘The size distribution of coal particles in a Circulating Fluidized Bed (CFB) boiler plays a crucial role in the complicated combustion, heat exchange and pollutant emissions in such a plat. Therefore, it is fundamental to study the different factors having influence on the size distribution of coal particles. Above all, the coal itself and in particular, the coal combination phenomenon is a very influent factor. In the frame of this work, the coal nature (elementary composition) and coal internal structure (mineral components) are studied in detail. At this intermediary stage, experiments on three typical Chinese coals on a l.5 MWt CFBC pilot plant have been made. Some primary fragmentation tests have also been made in a small lab scale fluidized bed reactor. The results from the hot pilot test show i) the variation of coal ash distributions and other CFB performance data due to the cyclone and the coal characteristics and ii) the variation of desulfurization efficiency with limestone. Whereas the bench scale primary fragmentation test, likely linked to the caking propriety of a coal, does not seem to change considerably the char size distribution.
基金the National Program on Key Basic Research Project(973 Program)of China(No.2014CB744305)is gratefully acknowledged.
文摘In this paper,the combustion process of oil shale semicoke was investigated by modeling,where intraparticle mass transfer resistance was especially considered.The ash formation and attrition characteristics of oil shale semicoke were also investigated by a laboratory test procedure.The burnout time and residence time of different particle sizes were predicted,and the maximum particle size of which oil shale semicoke could be burned out in a 3 MW circulating fluidized bed boiler was obtained.
