Life Cycle Assessment of Biogas Upgradation Using Microbial Electrosynthesis

Abstract

This thesis evaluates a life cycle assessment (LCA) framework for biogas upgradation. A study and evaluation were conducted by comparing high-pressure water scrubbing (HPWS) for biogas upgrading and integration of the Microbial electrosynthesis (MES) system. MES system is attached as a second reactor with anaerobic digestion (AD), from this integrated system biogas with higher methane content is pushed towards the biogas upgrading system. The goal and scope, and inventory analysis are addressed with the framework for both MES and HPWS cases. Global warming potential (GWP) and Eutrophication potential (EP) are mainly focused on environmental analysis in this system because the emission from the upgrading system primarily accounts for the GWP and eutrophication potential. Data are collected from different literature reviews and databases provided for LCA where the emissions from different parts of the process are compared. The study reveals that AD attached to the MES can reduce environmental emissions comparing to AD without MES. A basis for assessing potential improvements in the environmental performance of the biogas upgrading system is investigated, and the reasons behind the lack of data have been discussed. Sufficient and appropriate data is valid for future studies in this area to perform better LCA for the upgrading system.