Department of Chemical Engineering, Ahmadu Bello University, Zaria, Nigeria.
Department of Chemical Engineering, Chulalongkorn University, Bangkok, Thailand.
Sci Rep. 2022 Dec 5;12(1):20971. doi: 10.1038/s41598-022-24854-7.
A comparative sustainability study of bioethanol production from selected starchy feedstocks that are abundantly available was carried out in this work. This is to ensure the safe, reliable, and efficient production and consumption of fuel-grade bioethanol. The analysis utilised the established economic minimum bioethanol plant capacity of 158,000 m/annum. The processing flowsheet model utilised was the same for each feedstock. The sustainability study's economic, environmental, and energy perspectives were investigated. The economic and environmental indices were assessed using Superpro Designer and openLCA sustainability software, respectively. Exergy and lost work were subsequently estimated manually with Microsoft Excel. The economic analyses showed that the plants using cassava and sweet potato initially had the highest return on investment (ROI) of 64.41 and 41.96% respectively at a minimum of 80% plants' capacity utilisation. The break-even point occurs at a bioethanol price of $3.27 per gallon, beyond which positive net present values were obtained for the four processes. The least profitable plant was based on sorghum recording an ROI value of 34.11%. The environmental assessment on the four selected feedstocks showed that the processes based on cassava, corn, sweet potato, and sorghum recorded encouraging global warming potential (GWP) of 0.2452, 0.2067, 2.5261, and 0.2099 kg CO equivalent respectively. Cassava and corn emerged as the two most economically viable feedstocks when economic parameters were adjusted to include pollutants emission/discharge costs but with a slight decrease in profitability indices. The lost work analyses showed that distillation columns were the least energy-efficient units in the four bioethanol production routes assessed, recording loss work of about 61, 68, 34, and 49 MW for cassava, sweet potato, corn, and sorghum processing plants respectively. However, the net energy balance (NEB) and energy renewability results of the four production routes showed that the processes utilising the four selected starchy biomass feedstocks are more sustainable compared to fossil fuels.
本工作对具有丰富资源的几种淀粉质原料生产生物乙醇进行了可持续性比较研究，以确保燃料级生物乙醇的安全、可靠和高效生产与消费。该分析利用了经济可行的最小生物乙醇工厂产能 15.8 万立方米/年。每种原料都使用相同的加工工艺流程模型。从经济、环境和能源角度研究了可持续性。使用 Superpro Designer 和 openLCA 可持续性软件分别评估了经济和环境指标。利用 Microsoft Excel 手动估算了火用和损失功。经济分析表明，在最小 80%工厂产能利用率下，以木薯和甘薯为原料的工厂最初具有最高的投资回报率（ROI），分别为 64.41%和 41.96%。收支平衡点出现在生物乙醇价格为 3.27 美元/加仑时，四个过程都获得了正的净现值。最不盈利的工厂是基于高粱的，投资回报率为 34.11%。对四种选定原料的环境评估表明，基于木薯、玉米、甘薯和高粱的工艺分别记录了令人鼓舞的全球变暖潜势（GWP）值为 0.2452、0.2067、2.5261 和 0.2099kg CO 当量。在调整经济参数以包括污染物排放/泄漏成本，但略微降低盈利能力指数后，木薯和玉米成为两种最具经济可行性的原料。损失功分析表明，在评估的四种生物乙醇生产路线中，蒸馏塔是四个生物乙醇生产厂中效率最低的单元，记录的损失功分别约为 61、68、34 和 49MW 用于木薯、甘薯、玉米和高粱加工厂。然而，四个生产路线的净能量平衡（NEB）和能量可再生性结果表明，与化石燃料相比，利用四种选定的淀粉质生物质原料的工艺更具可持续性。
