Operation Characteristics of a Clapboard–type Internal Circulating Fluidized Bed Gasifier for Biomass

摘要

The operation characteristics of a Clapboard-type Internal Circulating Fluidized Bed Gasifier (CICFBG) for biomass were studied. Cold-state experiments were carried out to investigate the particle flow characteristics and thermal-state experiments were conducted under different conditions by using rice husk and wood sawdust. The results show that the CICFBG could be operated at 790-850 o C stably with gas yield ranging from 1.6 to 1.9Nm 3 /kg, the carbon content in the fly ash is about 10.4%. The gasification efficiency of the CICFBG is similar with that of traditional Circulating Fluidized Bed Gasifier (CFBG) and much higher than that of bubbling fluidized bed gasifier. Its carbon conversion rate increases obviously at ER=0.25-0.27 and maximum gasification efficiency can be obtained at optimized air distribution rate of 2.4-2.9. To prevent the gasifier from coking, it is found that the temperature in the gasifier should be regulated at about 850 o C, the temperature difference and pressure difference of the bed material should be controlled within 60 o C and 3000Pa, espectively.