自由落下床中生物质与煤共热解的协同效应对焦油组成的影响

利用溶剂萃取-柱层析方法,将自由落下床中豆秸与大雁褐煤共热解以及单种原料热解的液体产品分为沥青烯、酚类、脂肪烃类、芳香烃类和极性物等组分。结果表明,共热解的沥青烯产率为11.4%,低于根据煤和生物质单独热解的质量加权平均计算值19.0%,且芳香性增大;与计算值相比,低分子量的酚类、甲基苯酚、二甲基苯酚及其衍生物的含量提高了5%;而且长侧链的脂肪烃含量减少。共热解焦油的芳香类组分中十氢萘的质量分数是43.37%,但其在单一原料热解焦油中并没有被检测到。热解油分析结果表明,自由落下床生物质与煤快速共热解过程中存在协同效应,其主要原因是,发生氢解和加氢反应。煤与生物质共热解有利于产生低分子量的化合物,改善油品的质量。

Effect of synergism between biomass and coal during co-pyrolysis in a free fall reactor on tar components

The liquid products from co-pyrolysis of Dayan lignite(DY) and legume straw(LS) and from pyrolysis of the single fuel were classified into asphalts,phenols,aliphatic,aromatics and polar fractions by solvent extraction-column chromatography.Compared with the calculated yield of asphalts,i.e.the mass weighted mean value 19.0% from pyrolysis of the single coal and biomass,the experimental yield from co-pyrolysis decreased to 11.4%,and the aromaticity of the co-pyrolysis asphalts increased.At the same time,the yield of light molecular weight phenols,methylphenol,dimethylphenol and their derivatives increased at about 5% during the co-pyrolysis;while the content of aliphatic hydrocarbons with long chains decreased.The content of decalins was 43.37% in aromatic fraction of the co-pyrolysis tar,whereas it was almost not found in the tars from pyrolysis of the individual fuel.These results verified that the synergy existed during co-pyrolysis of coal and biomass under the experimental conditions.It was contributed to the reactions such as hydropyrolysis and hydrogenation during co-pyrolysis of coal and biomass under the hydrogen atmosphere mainly supplied by biomass pyrolysis.Co-pyrolysis of coal and biomass favors producing low molecular weight compounds and improving the quality of the liquid product.