Hydrothermal liquefaction of sewage sludge into biocrude: Effect of aqueous phase recycling on energy recovery and pollution mitigation
Hydrothermal liquefaction of sewage sludge into biocrude: Effect of aqueous phase recycling on energy recovery and pollution mitigation
复制标题
将污水污泥水热液化为生物原油：水相回收对能量回收和污染缓解的影响
DOI：
10.1016/j.watres.2022.119278
复制
发表时间：
2022
期刊：
影响因子：
12.8
通讯作者：
Rundong Li
中科院分区：
文献类型：
--
作者：
Hongmin Song;Tianhua Yang;Bingshuo Li;Yao Tong;Rundong Li
污水污泥水热液化（HTL）面临着生物原油收率低、大量难处理水相和重金属污染的挑战。在本研究中，HTL 产生的水相作为溶剂回收，旨在提高生物原油产量并减轻潜在污染。结果表明，水相循环利用使生物原油收率从17.9%提高到30.5%，能量回收率从40.3%提高到61.7%。回收后可使固体残渣中Zn、Cu、Pb、Cr含量增加2.7~3.0倍。值得强调的是，回收后水相COD降低了24.9%。然而，强化的蛋白质水解过程将生物原油的热值从36.4 MJ/kg降低至28.5 MJ/kg，并促进氮迁移到水相，这对于直接用于柴油发动机并不有利。分析表明，水相中的酮类和酚类作为反应物参与HTL过程，酸类促进污泥中蛋白质的水解。总体而言，水相的循环利用有效提高了污泥HTL的能量回收率并减轻了污染。
Hydrothermal liquefaction (HTL) of sewage sludge is facing the challenges of low biocrude yield, a large number of intractable aqueous phase and heavy metals pollution. In this study, the aqueous phase produced by HTL was recycled as solvent with an aim to improve the biocrude yield and mitigate potential pollution. Results showed that the recycling of aqueous phase increased the biocrude yield from 17.9 to 30.5% and the energy recovery ratio from 40.3 to 61.7%. The recycling could increase the contents of Zn, Cu, Pb and Cr in solid residues by 2.7−3.0 times. It is worth emphasizing that the recycling reduced the COD of aqueous phase by 24.9%. However, the enhanced protein hydrolysis process reduced the calorific value of biocrude from 36.4 to 28.5 MJ/kg, and promoted the migration of the nitrogen to the aqueous phase, which was not environmentally favourable for the direct usage in diesel engines. Analysis showed that the ketones and the phenols in aqueous phase participated in HTL process as reactants, and the acids promoted the hydrolysis of protein in the sludge. Overall, the recycling of aqueous phase effectively improved the energy recovery and alleviated pollution of the sludge HTL.