Sustainable process design of biofuel: bioethanol production from cassava rhizome

Abstract

This study focused on the sustainable process design of bioethanol production from cassava rhizome using various tools, including process simulation, sustainability analysis, economic evaluation and life cycle assessment (LCA). The process simulator program. PRO/II 9.1, was used to generate a base case design of the bioethanol conversion process using cassava rhizome as a feedstock. The sustainability analysis software, SustainPro, was then used to analyze relevant indicators in sustainability metrics, which were further employed to provide directions for improvements. To evaluate profitability of the process, ECON software was employed. Lastly, the life cycle environmental impact associated with bioethanol production was evaluated by using LCA software, SimaPro 7.1. Several alternative designs were generated and compared with the base case design in terms of economics, energy and environment in order to identify the most sustainable design for the production of ethanol with a capacity of 150.000 liters/day of ethanol production from cassava rhizome. Based on SustainPro results, three ideas of new design alternatives were generated for possible improvement. The ideas were heat integration to reduce energy; wastewater recovery using membranes; and the combustion of lignin as fuel. Based on these ideas, seven alternative designs were generated from different combinations of these ideas. Finally, all alternatives were compared with the base case design to show the improvements of these designs for more sustainable.