低阶煤与生物质在热溶剂提质萃取过程中的相互作用

作者前期工作中提出了一种针对生物质废弃物或低阶煤的热溶提质萃取方法,该方法可以在350℃下实现生物质或低阶煤的提质及多级分离,获得高附加值的萃取物。与生物质的热溶提质萃取比较,低阶煤的萃取物收率较低。本研究提出对生物质和低阶煤混合物进行热溶提质萃取,通过两者的物理化学相互作用,来提高其萃取收率。研究结果表明,对两者混合物热溶剂提质分离得到萃取物的产率及元素组成与理论计算结果略有不同,理论计算结果是假设生物质与煤之间无交互作用而得到的。煤中的矿物质对生物质热分解起催化作用,导致收率有所增加。煤、生物质及其混合物通过热溶剂提质分离得到的萃取物的元素组成、分子量分布、化学结构、热分解和热塑性非常相似。总体而言,低阶煤与生物质在热溶剂提质萃取过程的交互作用较小。但是,本研究证明了热溶提质萃取方法不仅适用于煤或生物质,也适用于它们的混合物。这意味着热溶剂提质萃取法可以在不改变任何工艺条件参数的情况下,以煤、生物质及其混合物作为原料。

Interaction between low-rank coal and biomass during degradative solvent extraction

A degradative solvent extraction at around 350°C for low-rank coal or biomass wastes upgrading and fractionation was proposed in our previous work. The extraction yield of low-rank coal is relatively lower than that of biomass. In this work the blends of low-rank coal and biomass were treated by this method at 350°C to investigate the interaction between them. The results showed that the yields and elemental compositions of the extracts obtained from the blends were slight different to the calculated results, which were calculated by assuming that there was no interaction between the coal and biomass. The slight promotion of yield was judged to be caused by the catalytic action of the minerals in the coal for thermal decomposition of biomass. It was worth to note that the elemental composition, molecular weight distribution, chemical structure, thermal decomposition behavior and thermoplastic behavior of the extracts obtained from low-rank coal, biomass and their blend, were rather similar to each other, independent of the properties of the raw feedstocks. Overall, the interaction between low-rank coal and biomass during the extraction was not significant. On the other hand, the proposed degradative solvent extraction method was fit not only by single low-rank coal and biomass but also by their blends to produce the product having similar physicochemical properties. This implied that an industrial system of degradative solvent extraction can use coal, biomass or their blends as feedstock at the same time without modification or adjustment.