基于组分的生物质分级液化机理及产物分离方法研究

As an important renewable resource, biomass provides the material basic for the sustainable development of energy and chemical industry. According to the characteristics of biomass resources, it is significantly important to develop an effective conversion technology in that the three major components (celluose, hemicellouse and lignin) are separately converted into different high-value products. In a moderate hydrothermal condition, hemicellouse is completely hydrolyzed while lignin is modified. Then a subsequent stepwise pyrolysis can be used to achieve separate liquefaction and product enrichment for cellouse and lignin. This method provides a good foundation for the separation and utilization of liquid products. In this project, a combination between the selective adsorption of char and the stepwise liquefaction of biomass components is developed. The process mechanism of the hydrothermal pretreatment and the stepwise pyrolysis will be studied and the optimal conditions will be determined to achieve high value-added product enrichment in the liquid products from different stages. At the same time, the evolution of the structure and morphology of the char and the adsorption characteristics of char will be analyzed to find out an effective modified method based on different adsorption application. Ultimately, a new conversion process will be developed base on the stepwise liquefaction of biomass components, char adsorption and separation process, and this process will establish a new approach for biomass highly efficient conversion and utilization.

生物质是重要的可再生资源，是能源和化工可持续发展的物质基础。根据生物质资源的特点，将其有机组分（纤维素、半纤维素和木质素）分别利用是生物质转化的重要发展方向。在较温和的水热条件下，生物质中的半纤维素完全水解而木质素发生改性，进一步可利用分级热解的方法实现纤维素和木质素的分级液化和产物富集，为液化产物的分离和高值化利用提供了很好的基础。本项目将焦炭选择性吸附与生物质分级液化相结合，研究生物质水热预处理、分级热解过程机理，探索实现各阶段液体产物中高附加值成分富集的条件，分析焦炭结构和形貌的演变规律以及对吸附特性的影响，探索实现焦炭吸附选择性调控的活化改性方法，最终形成生物质三组分分级液化及其产物富集和分离的新工艺，为生物质高效转化和高值化利用提供一条新的途径。

生物质具有复杂的有机组分结构，是生物质利用的物质基础。为实现生物质资源的高效转化和高值化利用，本项目采用水热预处理和分级热解有机结合的新工艺，对生物质水热预处理和分级热解的过程机理进行深入研究，探索实现各阶段液体产物中高附加值成分调控和富集的条件。研究结果表明，在温和水热条件下，生物质中的半纤维素充分水解生成糠醛，同时一部分木质素发生降解；经过水热预处理的生物质的灰分和半纤维素含量大幅减少，进一步在400℃左右低温热解条件下，得到的液体产物中富含左旋葡聚糖等糖类物质；而经过前两级处理后的固体产物，所含木质素难以热解，采用分子筛催化剂在高温下催化热解可以得到成分相对集中的酚类和芳香烃产物；基于上述结果，最终确定了生物质分级液化各阶段的最佳反应条件，实现目标产物的最大富集。本项目研究成果对深入了解生物质三组分在水热、热解以及催化热解条件下的反应路径有重要意义，同时为生物质制备高品质液体燃料技术发展提供技术支持。