生物质热解气分级冷凝对生物油特性的影响

Influence on bio-oil by fractional condensation of biomass pyrolysis vapor

利用分级冷凝手段对成分复杂的生物质热解气在不同冷凝温度下的分离特性进行研究,将成分复杂的混合物依据自身露点的不同,通过控制冷凝温度,实现生物油的分组富集。对热解气在不同冷凝温度（300℃、100℃、0℃和-20℃）下生成的各级液体产物的物理特性和化学成分进行系统分析。生物质热解气经过分级冷凝处理后得到4组生物油样品,其中0℃时得到的生物油产率最大,超过液体总量的50%;其次是100℃时的冷凝产物,为分子量80~200的有机物,以杂酚类物质为主;300℃冷凝得到的产物为沥青类物质,不含水分,状似固体碳,没有流动性。分级冷凝能够很好地将水分和有机酸成分从生物油中分离出来,几乎所有的有机酸和超过80%的水分都富集在0℃和-20℃冷凝组分中。结合各组分GC-MS的分析结果,对乙酸、苯酚、愈创木酚和多环芳烃等生物油中典型有机组分的分布特性进行分析总结,得到各类物质在分级冷凝过程中的富集规律。

The composition of biomass pyrolysis vapors is complex. Their separation properties were investigated by using fractional condensation under different temperature. According to the distinct dew points of the compound containing, the enrichments with different bio-oil grouping were produced by controlling condensed temperature such as 300℃, 100℃, 0℃ and？20℃, and so four groups of bio-oil samples were obtained during our experiment of fractional condensation and their characteristics of each fraction were studied and analyzed. The yield of liquid condensed in 0℃ is the highest and more than 50% of the whole bio-oil, while that did in 100℃ contained the organics with molecular weight of 80 to 200, mainly fusel phenol compounds. The fraction collected in 300℃ was bitumen, which did not contain moisture, look like solid carbon and there was no liquidity and viscosity. Water and organic acids had well be separated from bio-oil in fractional condensation, more than 80% water and nearly all the organic acids were collected in the enrichments at 0℃ and？20℃. The distribution of some typical components including acetic acid, phenols, guaiacol, and PAH under different condensed temperature was analyzed by GC-MS, and enrichment rule was obtained based on behaviors of typical compounds condensing in bio-oil.