Biogas as a Renewable Energy Source: Focusing on Principles and Recent Advances of Membrane-Based Technologies for Biogas Upgrading

Abstract

In this work, a comprehensive discussion of biogas upgrading using membrane technologies is presented. Bio-methane obtained from biogas upon carbon dioxide removal is an attractive source of clean energy, and several techniques have been developed for this purpose. These technologies are chemical absorption, water scrubbing, physical absorption, adsorption, cryogenic separation, and membrane separation. Among these techniques, membrane separation outstands due to its promising economic viability. In this work, general characteristics of biogas and its upgrading processes are explained. Then membrane technology for biogas upgrading through gas permeation is analyzed in detail. Gas permeation phenomena, membrane materials, membrane modules, different types of process configuration, and commercial biogas plants based on membrane technologies are deeply investigated. Polymeric membrane materials are under continuous development, and this will facilitate the implementation of membrane-based biogas upgrading processes in many industrial areas. Single-stage configurations are not able to produce both high methane purity and a high recovery percentage. Thus, multistage configurations play an important role in biogas upgrading when membranes are selected to facilitate the CH4/CO2 separation. In this scenario, it is expected that membrane-based biogas upgrading methods will significantly contribute to open new approaches in the urgent matter of sustainable energy technologies.