Rational Scale-Up of a methane producing bioelectrochemical reactor to 50 L pilot scale

Abstract

The field of microbial electrosynthesis gained much attention since it allows the conversion of electrical energy into valuable chemicals. The technology is now on the turning point from lab scale to first industrial applications. We show a rational Scale-Up using similarity theory from a 1-L reactor to a 50-L reactor for the production of methane via bioelectromethanogenesis. Pure culture experiments with Methanococcus maripaludis were carried out. Since this was the largest pure culture bioelectromethanogenesis experiment shown so far, also the total methane production rate of 11.7 mmol/d was the highest reported. However, the space time yield was with 0.23 mmol/l*d only 16% of the yield reached in the lab scale reactor. The Coulombic and energy efficiency were much higher than in lab scale. Different reasons for this gap, especially inhibition by reactor material and low current densities, are discussed to avoid such losses in performance in future research.