Myint Ni Ni, Jaruensri Kongpetch, Sakulshah Netipon, Thanapimmetha Anusith, Saisriyoot Maythee, Chiarasumran Nutchapon, Wang Hui-Min David, Srinophakun Penjit
Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand.
Graduate Institute of Biomedical Engineering, National Chung Hsing University, Taichung 402, Taiwan.
ACS Omega. 2025 May 22;10(21):21280-21291. doi: 10.1021/acsomega.4c10777. eCollection 2025 Jun 3.
This study aims to evaluate the techno-environmental impacts of biodiesel production from acid oil using a one-step acid catalyst and a two-step immobilized enzyme and acid catalyst esterification. Acid oil was obtained by purifying crude glycerol with pure glycerol and salt as by-products. The experiment was performed to optimize the conversion of the acid oil to biodiesel. The one-step process involves 4% sulfuric acid, a methanol-to-oil molar ratio of 26:1, and a reaction time of 3.4 h. The two-step esterification comprised two stages: the first stage employed immobilized lipase on chitosan. The optimal conditions of the first stage were a 5:1 methanol-to-oil molar ratio, 37 wt % enzyme loading, and a reaction time of 17 h. The second stage of the two-step process involved 3% sulfuric acid with a methanol-to-oil molar ratio of 15:1 for 4 h. Then, a techno-environmental assessment was performed to compare the midpoint impacts of the one-step and two-step esterification. The study generated 7 cases to investigate the significant environmental effects of glycerol (case 1), particularly on global warming potential. It examined the impact of different electricity sources, natural gas (cases 2, 3, and 6) and hydropower (cases 4, 5, and 7), on biodiesel production. Comparing SC-1 (one-step esterification with an acid catalyst) and SC-2 (two-step esterification with an enzyme and acid catalyst), the study found that SC-2 was technically feasible due to lower energy consumption, less chemical use, and less wastewater, but SC-1 was more environmentally friendly. Due to enzyme preparation, SC-2 has had a higher impact on terrestrial ecotoxicity, human noncarcinogenic toxicity, global warming, and land use. The study suggested that biodiesel factories should purify crude glycerol to minimize its environmental effects and enhance biodiesel production's ecological benefits and sustainability.
本研究旨在评估使用一步法酸催化剂以及两步法固定化酶和酸催化剂酯化法从酸性油生产生物柴油的技术环境影响。酸性油是通过用纯甘油和盐作为副产物纯化粗甘油而获得的。进行该实验以优化酸性油向生物柴油的转化。一步法工艺使用4%的硫酸，甲醇与油的摩尔比为26:1，反应时间为3.4小时。两步酯化包括两个阶段：第一阶段使用壳聚糖固定化脂肪酶。第一阶段的最佳条件是甲醇与油的摩尔比为5:1、酶负载量为37 wt%、反应时间为17小时。两步法工艺的第二阶段使用3%的硫酸，甲醇与油的摩尔比为15:1，反应4小时。然后，进行了技术环境评估，以比较一步法和两步法酯化的中点影响。该研究生成了7个案例，以调查甘油（案例1）的重大环境影响，特别是对全球变暖潜能值的影响。它研究了不同电源，天然气（案例2、3和6）和水电（案例4、5和7）对生物柴油生产的影响。比较SC-1（用酸催化剂的一步法酯化）和SC-2（用酶和酸催化剂的两步法酯化），该研究发现SC-2在技术上是可行的，因为其能耗更低、化学品使用更少且废水更少，但SC-1在环境方面更友好。由于酶的制备，SC-2对陆地生态毒性、人类非致癌毒性、全球变暖和土地利用有更高的影响。该研究建议生物柴油工厂应纯化粗甘油，以尽量减少其环境影响，并提高生物柴油生产的生态效益和可持续性。
