Pilot experiment of gasification of corn straw in circulating fluidized bed

doi:10.16085/j.issn.1000-6613.2017-1851

Abstract

Abstract: The corn straw is the residues produced in the process of agricultural production. Gasification process is an important choice for corn straw's treatment and application. A circulating fluidized bed gasification pilot plant was built to study the effect of air equivalence ratio and water content of raw materials on gasification characteristics, such as reaction temperature, gas composition and calorific value, gasification efficiency, and tar content in produced gas. The optimized operating conditions under different loadings were obtained by changing the feed quantity experiment. The results showed that the gasification temperature and CO₂ in fluidized bed gradually increased with the increase of ER, while the calorific value and tar content both decreased. The gasification efficiency increased first but then decreased. The optimum range of ER was 0.26, and the gasification efficiency and calorific value could reach 70.2% and 5.1MJ/m³ respectively. The increase of raw material moisture content decreased the reaction temperature in the gasification furnace. H₂ content, gas calorific value and gasification efficiency all increased with the increase of moisture content from 5% to 15%. The gas calorific value and gasification efficiency declined rapidly when moisture content increase from 15% to 25%. The better operating conditions were obtained when gasifier operated within a load range 66%-120% of the design feeding rates. The optimum range of ER was 0.26-0.3, and the calorific value and gasification efficiency were 4.8-5.1MJ/m³ and 69%-72% respectively.

Key words: corn straw, gasification, circulating fluidized bed, air equivalence ratio, water content

摘要： 玉米秸秆是农业生产过程中产生的剩余物，其热解气化是秸秆类生物质处理应用的重要选择方向。为此，采用循环流化床气化中试装置对玉米秸秆进行了气化试验，研究空气当量比ER、原料含水率对反应温度、气化燃气组分与热值、气化效率及燃气中的焦油含量等气化特性影响规律，并通过改变进料量试验得到了在不同负荷运行条件下的优化工作参数。结果表明：①随着ER的增大，循环流化床气化炉内的反应温度升高，气化燃气中的CO₂含量增加，焦油与CO含量及燃气热值降低，气化效率随ER的增大呈现先增大后减小趋势，较理想的ER为0.26，此时的气化效率达到70.2%、燃气热值为5.1MJ/m³；②原料含水率的增大降低了气化炉内的反应温度，当原料含水率在5%～15%之间逐渐增大时，燃气中的H₂含量、燃气热值及气化效率均有提升，当含水率由15%继续增大到25%过程中，燃气热值与气化效率均出现了快速下降；③根据气化炉额定进料量设计值，改变进料负荷在66%～120%范围内，调节ER在0.26～0.3时均可得到较好的运行工况，对应得到的燃气热值为4.8～5.1MJ/m³、气化效率为69%～72%。

关键词: 玉米秸秆, 气化, 循环流化床, 空气当量比, 含水率

CLC Number:

YU Jie, DONG Yuping, CHANG Jiafu, DONG Lei. Pilot experiment of gasification of corn straw in circulating fluidized bed[J]. Chemical Industry and Engineering Progress, 2018, 37(08): 2970-2975.

于杰, 董玉平, 常加富, 董磊. 玉米秸秆循环流化床气化中试试验[J]. 化工进展, 2018, 37(08): 2970-2975.

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