Biocatalytic methanation of hydrogen and carbon dioxide in an anaerobic three-phase system

Abstract

A new type of anaerobic trickle-bed reactor was used for biocatalytic methanation of hydrogen and carbon dioxide under mesophilic temperatures and ambient pressure in a continuous process. The conversion of gaseous substrates through immobilized hydrogenotrophic methanogenic archaea in a biofilm is a unique feature of this type of reactor. Due to the formation of a three-phase system on the carrier surface and operation as a plug flow reactor without gas recirculation, a complete reaction could be observed. With a methane concentration higher than cCH4=98%, the product gas exhibits a very high quality. A specific methane production of PCH4=1.49Nm3/(mSV3d) was achieved at a hydraulic loading rate of LRH2=6.0Nm3/(mSV3d). The relation between trickle flow through the reactor and productivity could be shown. An application for methane enrichment in combination with biogas facilities as a source of carbon dioxide has also been positively proven.