CH4 production at moderate H2/CO2 pressures - insights on the specific hydrogenotrophic methanogenic activity

Abstract

CO2 is one of the main contributors to greenhouse gases (GHGs), being its emission to the atmosphere one of the major driver of global climate change. Biological methanation of CO2 using renewable H2 provides a promising approach to use of superplus renewable electrical power to produce a gaseous fuel. CH4 is considered an important renewable energy carrier, that has a wide range of applications such as natural gas for distribution. Hydrogenotrophic methanogens are key elements in the CO2/H2 methanation process. Thus the importance to study the specific hydrogenotrophic methanogenic activity (SHMA). The effect of the initial substrate (H2/CO2) pressure on the SHMA was investigated in two different pressurized bioreactors. The results suggest that in addition to the increase of the initial substrate pressure, also the bioreactor configuration influence the SHMA, which is crucial for the success of biological CO2 methanation technologies but also in anaerobic bioreactors treating wastewaters.