生物质三组分在聚乙二醇辅助热解液化过程中的协同作用

Synergetic Mechanism of Three Components of Biomass Liquefaction in Polyethylene Glycol

将三大组分的模型化合物微晶纤维素、木聚糖和木质素进行不同配比得到合成生物质,对不同配比的合成生物质样品进行热重(TG)分析,研究了其溶剂辅助热解液化行为,并得出三大组分在溶剂辅助热解液化过程中的协同作用。研究发现:温度低于350℃时,半纤维素对纤维素的降解有一定的促进作用;而高于350℃时,则有明显的抑制作用;半纤维素和纤维素均对木质素的降解起到抑制作用。采用极端顶点法选取典型配比的合成生物质,运用热裂解-色谱-质谱联用技术(Py-GC/MS)探究了合成生物质的溶剂辅助热解液化产物分布,得出了生物质各组分对溶剂辅助热解液化产物分布的影响。结果表明:合成生物质中的木质素含量较高会促进酸类物质的生成,纤维素和半纤维素的溶剂辅助热解液化产物对木质素溶剂辅助热解生成酚类化合物有一定的抑制作用;对于酯类化合物来说,合成生物质溶剂辅助热解液化都生成了较多的酯类物质,生物质三组分不同的配比促进了酯类化合物的生成。

The thermogravimetric analysis（TG） was carried out on the synthesized biomass samples with different proportions of microcrystalline cellulose, xylan and lignin. The co-solvent liquefaction behavior and the synergistic effect of the three- components in the co-solvent liquefaction process were obtained. When the temperature was lower than 350 ℃, the hemicellulose had a certain promoting effect on the degradation of cellulose; when it was higher than 350 ℃, there was a significant inhibitory effect. Hemicellulose and cellulose inhibited the lignin degradation; and then the extreme vertex method was used to select the typical ratio of synthesized biomass. The pyrolysis liquefaction products of the co-solvent of synthesized biomass were investigated by pyrolysis chromatography mass spectrometry （Py-GC/MS）. The effects of the components of biomass on the co-solvent pyrolysis products were obtained. The results indicated that higher percentage of lignin in synthesized biomass promoted theformation of acids. The existence of cellulose and hemicellulose restrained the production of phenols during lignin co-solvent pyrolysis. More esters were obtained from synthesized samples co-solvent pyrolysis, different proportion of three-components promote the formation of esters.