生物质热解分级冷凝制备多品级生物油

FRACTIONAL CONDENSATION OF BIOMASS PYROLYSIS GAS FOR MULTI-QUALITY BIO-OILS

为了分品级充分利用生物油,根据其组分之间物理化学性质的差异,通过控制冷凝温度,在不同冷凝段对沸点相近的物质进行收集,建立一套生物质热解分级冷凝中试装置。采用螺旋式热解反应器,冷凝器设计为4级,其中第1级冷凝器采用喷雾方式进行直接冷却,其余各级均采用列管式换热器进行间接冷却。试验结果表明：4级冷凝器的出口温度分别设置为220、105、70、20℃时,不同喷淋介质对1、2级冷凝器生物油收率的影响不大,使用甲醇喷淋时,第4级冷凝器生物油收率较高;而Bio-3喷淋时,第3级冷凝器生物油收率较高,且第2级生物油和第4级生物油的热值升高、粘度增大,同时N元素和S元素含量也会增大。GC/MS分析表明,第2级生物油的主要成分为苯酚、间甲酚、4-乙基苯酚、4-甲基愈创木酚等酚类产物,其作为化工原料价值较高;第3级生物油具有最高含量的水和乙酸,同时含有少量酚类,可能用作木醋液;第4级生物油的成分主要为苯、甲苯、苯酚、4-乙基苯酚等高热值组分,同时其热值较高、水分较低、粘度稍大,经过甲醇稀释等降粘处理后可用作液体燃料。

In order to better use of bio-oil,a pilot experimental device was established to collect bio-oils in a seriescondensers by controlling the condensing temperature. A screw reactor was used and the pyrolysis gas was condensed infour condensers which a spray condensation was used for the first condenser and tube heat exchange was used for theothers. The result showed that the pyrolysis vapors passed through the four condensers at 220,105,70 and 20 ℃,compared to spray condensation of methanol,the yield of bio-oil in the fourth condenser decreased and the yield of biooil in the third condenser increased,what＇s more the heating value and viscosity of bio-oils in the second and fourthcondensers increased and the content of N,S in the bio-oils increased when the bio-oil in the third condenser was used asworking fluid of spray. GC/MS analysis indicated that the main components of bio-oil in the second condenser werephenol,m-cresol,4-ethyl phenol,2-methoxy-4-methyl phenol,etc. which may be used as chemicals,the third condenserthree collected the highest contents of water and acetic acid,also a small amount of phenols which may be used aspyroligneous and the main components of bio-oil in the fourth condenser were benzene,toluene,4-ethyl phenol,etc.which may be used as fuel.