Department of Agricultural & Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, P. R. China.
Environ Sci Technol. 2021 Feb 2;55(3):1973-1983. doi: 10.1021/acs.est.0c05924. Epub 2021 Jan 12.
Algal bloom microalgae are abundant in polluted water systems, but their biocrude oil production potential via hydrothermal liquefaction (HTL) is limited. This study proposed a novel process that combined biological (dark fermentation) and thermochemical (HTL) techniques aimed at changing the feedstock characteristics to be more suitable for thermochemical conversion, herein named integrated dark fermentation-hydrothermal liquefaction (DF-HTL). DF-HTL conversion of algae significantly enhanced the biocrude oil yield (wt %), carbon content (mol), energy content (MJ), and energy conversion ratios by 9.8, 29.7, 40.0, and 61.0%, respectively, in comparison to the control. Furthermore, DF-HTL processing significantly decreased the aqueous byproduct yield (wt %), carbon content (mol), nitrogen content (mol), and ammonia content (mol) by 19.0, 38.4, 25.0, and 13.2%, respectively, in comparison to the control. Therefore, DF-HTL reduced the environmental impact associated with disposing of the wastewater byproduct. However, DF-HTL also augmented the nitrogen content (mol) of the biocrude oil by 42.2% in comparison to the control. The benefits of DF-HTL were attributed to the increased acid content, the incorporation of H as a processing gas, and the enhancement of the Maillard reaction, which shifted the distribution of reaction products from the aqueous phase to the biocrude oil phase. This article provides insights into the efficacy of a novel integrated biological-thermochemical processing method with distinct environmental and energetic advantages over conventional HTL that heightens the biocrude oil yield for feedstocks with a high carbohydrate and a high protein content.
藻类水华微藻在受污染的水系中大量存在，但通过水热液化（HTL）将其生物原油产量潜力有限。本研究提出了一种新的工艺，将生物（暗发酵）和热化学（HTL）技术相结合，旨在改变原料特性，使其更适合热化学转化，称为集成暗发酵-水热液化（DF-HTL）。与对照相比，DF-HTL 转化藻类显著提高了生物原油产率（wt%）、碳含量（mol）、能量含量（MJ）和能量转化率分别为 9.8%、29.7%、40.0%和 61.0%。此外，DF-HTL 处理显著降低了水相副产物产率（wt%）、碳含量（mol）、氮含量（mol）和氨含量（mol）分别为 19.0%、38.4%、25.0%和 13.2%，与对照相比。因此，DF-HTL 减少了处理废水副产物带来的环境影响。然而，DF-HTL 也使生物原油中的氮含量（mol）比对照增加了 42.2%。DF-HTL 的好处归因于酸含量的增加、H 作为加工气的掺入以及美拉德反应的增强，这使得反应产物的分布从水相向生物原油相转移。本文提供了一种新颖的生物-热化学集成处理方法的有效性的见解，与传统的 HTL 相比，该方法具有明显的环境和能量优势，可提高高碳水化合物和高蛋白含量原料的生物原油产率。
