EXPERIMENTAL INVESTIGATION OF WOOD GASIFICATION IN AN UPDRAFT FIXED BED GASIFIER
Household updraft fixed bed gasifier displayed a wide application prospect in wide rural areas in China. However, it showed many problems need to be solved. In this work, the gasification performance was studied in-depth in a new type of updraft fixed bed gasifier with woodchips as biomass materials. Firstly, the temperature distribution of the gasifier and the composition and low heating value (LHV) of gas products at different running time and different heights were investigated with air flow rate kept constant at 1.9m3/h. It can be observed that the temperature of the oxidation zone increased rapidly from ambient temperature to 560℃ in 4 minutes after the gasifier startup, and the gas products could be ignited already. After 11 minutes, the temperature of the oxidation zone was increased up to ～960℃, and then it kept constant without obvious variant. With running time increasing, LHV of gas products increased. At～45 minutes, it caught the maximum value of 4.38MJ/m3. After 90 minutes, the rangeability of the gasifier temperature enlarged significantly, gas products LHV decreased sharply and the content of O2 and N2 increased while the combustible gas content decreased. As air flow rate of 1.gm3/h, under stable operation condition, the temperature inside the gasifier decreased greatly with the height increasing. As the height was higher than 480mm, the temperature changed slightly. Meanwhile, the gas composition and LHV of the gas products had been consistent with the outlet gas. The reaction type inside the gasifier had obvious height level characteristics. The carbon content of the bottom ash was 59.3％, the stack density of the bottom ash was 0.169g/cm3, fuel consumption was ～1.09kg/h, and the gasification efficiency was 63.69％. Then, the influence of air flow rate on the gasifier was studied with the air flow rate increasing from 1.1 to 3.5m3/h. It can be observed that the temperature of the oxidation zone increased sharply from 710 to 1129℃, the content of the combustible gas and LHV of the gas products increased first and then decreased, the LHV varied fiom 2.15 to 4.38 MJ/m3, and the maximum value was at ～1.9m3/h.
Up-draft fixed bed gasifier Air flow rate Temperature distribution Gas composition distribution Low heatingvalue
Bin LI Han-ping CHEN Hai-ping YANG Xian-hua WANG Shi-hong ZHANG
State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan,430074,China
国际会议
广州
英文
1117-1123
2008-12-03（万方平台首次上网日期，不代表论文的发表时间）