Algae biomass has recently attracted the attention of the green energy industry as a raw material for biofuels production. Their high-water content has led to the choice of hydrothermal liquefaction as a suitable way to convert them into bio-oil. From algae species to bio-oil as fuel, many steps are required, including the selection of algae species and process parameters (including catalysts), the liquefaction process, product separation, recovery of crude bio-oil, and subsequent upgrading (if the goal is to use the bio-oil as transportation fuel). This review gives some biochemical, elemental, and inorganic compositions of algae. The reaction mechanism of hydrothermal liquefaction is briefly described, with an emphasis on the influence of process parameters on the yield and quality of the crude bio-oil. The use of organic solvents as reaction media or for recovery of crude bio-oil from product mixtures is discussed. The research work on the catalytic hydrothermal upgrading of algae liquefied crude bio-oil in recent years is reviewed, and some conclusions are put forward. According to recent reports, there is a section devoted to the techno-economic analysis of the hydrothermal liquefaction process. Finally, the challenges that future research and new development strategies may face are proposed.

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藻类生物质的水热液化和后续粗制生物油的水热升级研究进展：简述

藻类生物质作为生物燃料生产的原料最近已引起了绿色能源产业的关注。它们的高水含量导致选择水热液化作为将其转化为生物油的合适方法。从藻类物种到以生物油为燃料，需要许多步骤，包括藻类种类和工艺参数（包括催化剂）的选择，液化过程，产品分离，粗制生物油的回收以及随后的提质（如果目标是是使用生物油作为运输燃料）。这篇评论给出了藻类的一些生化，元素和无机成分。简要介绍了水热液化的反应机理，重点介绍了工艺参数对粗生物油产率和质量的影响。讨论了使用有机溶剂作为反应介质或从产物混合物中回收粗生物油。综述了近年来藻类液化原油生物油催化水热提质的研究工作，并提出了一些结论。根据最近的报道，有一节专门讨论水热液化过程的技术经济分析。最后，提出了未来研究和新的发展战略可能面临的挑战。有一节专门讨论水热液化过程的技术经济分析。最后，提出了未来研究和新的发展战略可能面临的挑战。有一节专门讨论水热液化过程的技术经济分析。最后，提出了未来研究和新的发展战略可能面临的挑战。