生物质热解焦吸附模拟烟气中SO_2和NO的实验研究

Experimental Study on Adsorption Characteristics of SO_2 and NO Using Biomass-pyrolysis Chars

以麦秆、稻秆、棉花秆、玉米秆和稻壳等5种生物质原料为对象,在热解温度Tp 673~1 073 K范围内,采用快速热解和慢速热解方式制备了生物质焦,利用固定床吸附反应装置研究了焦粒粒径、热解温度、热解速率、烟气组成、吸附反应温度和生物质种类等因素对生物质焦吸附模拟烟气中SO2、NO的影响。结果表明：生物质焦对SO2的吸附效率和吸附量随着生物质焦粒径的减小而增加,但其增加趋势逐步减小。随着热解温度升高,生物质焦对SO2的吸附效率和吸附量均呈现先上升后下降的趋势。快速热解生物质焦对SO2和NO的单独吸附效率和吸附量均高于慢速热解焦。生物质焦对SO2和NO的吸附效率和吸附量均随着吸附反应温度的升高而下降。生物质焦对SO2吸附能力显著优于吸附NO的能力,模拟烟气中SO2组分对NO吸附具有显著促进作用。SO2和NO同时吸附时,WS-RP873型生物质焦对SO2的吸附量较单独吸附时减少了22.3%,但其对NO吸附量却提高了112%。在Tp 873K快速热解条件下,各种生物质焦对SO2吸附量顺序为麦秆焦〉玉米秆焦〉稻秆焦〉稻壳焦〉棉花秆焦,对NO吸附量顺序为麦秆焦〉稻秆焦〉玉米秆焦〉稻壳焦〉棉花秆焦。

Biomass-pyrolysis chars were prepared under rapid pyrolysis and slow pyrolysis at pyrolysis temperature（Tp） of 673-1 073 K from five kinds of biomass named wheat straw,rice straw,cotton stalk,maize stalk and rice husk.The effects of biomass char particle size,pyrolysis temperature,pyrolysis rate,composition of the simulated flue gas,adsorption reaction temperature,and biomass type on adsorption characteristics of SO2 and NO by using biomass-pyrolysis chars were carried out experimentally in a fixed-bed reactor.The results indicate that adsorption efficiency and adsorption capacity of SO2 over biomass-pyrolysis chars increase with decreasing the particle size of biomass chars;however,the increasing tendency is decreased gradually.With the increase of pyrolysis temperature,adsorption efficiency and adsorption capacity of SO2show a trend of increase first and decrease later.Individual adsorption efficiency and adsorption capacity of SO2and NO over biomass-pyrolysis chars prepared under rapid pyrolysis is better than that prepared under slow pyrolysis.Adsorption capacity of SO2 and NO over biomass-pyrolysis chars decreases with increasing of adsorption reaction temperature.Adsorption ability of SO2 is significantly better than that of NO over biomass-pyrolysis chars.SO2 in a simulated flue gas can promote the effect of NO adsorption significantly.At the condition of simultaneous adsorption of SO2 and NO by using biomass char named WS-RP873,SO2 adsorption capacity decreases 22.3% and NO adsorption capacity increases 112% while comparing with individual adsorption of SO2 or NO.At Tp 873K and rapid pyrolysis,the order of SO2 adsorption capacity over biomass-pyrolysis chars is confirmed as wheat straw char maize stalk char rice straw char rice husk char cotton stalk char,and the order of NO adsorption capacity is confirmed as wheat straw char rice straw char maize stalk char rice husk char cotton stalk char.