Hydrogen production from switchgrass via an integrated pyrolysis–microbial electrolysis process

Abstract

A new approach to hydrogen production using an integrated pyrolysis-microbial electrolysis process is described. The aqueous stream generated during pyrolysis of switchgrass was used as a substrate for hydrogen production in a microbial electrolysis cell, achieving a maximum hydrogen production rate of 4.3 L H2/L anode-day at a loading of 10 g COD/L-anode-day. Hydrogen yields ranged from 50±3.2% to 76±0.5% while anode Coulombic efficiency ranged from 54±6.5% to 96±0.21%, respectively. Significant conversion of furfural, organic acids and phenolic molecules was observed under both batch and continuous conditions. The electrical and overall energy efficiency ranged from 149-175% and 48-63%, respectively. The results demonstrate the potential of the pyrolysis-microbial electrolysis process as a sustainable and efficient route for production of renewable hydrogen with significant implications for hydrocarbon production from biomass.

Sustainable and Efficient Pathways for Bioenergy Recovery from Low-Value Process Streams via Bioelectrochemical Systems in Biorefineries

“…Synergy between biorefineries and BES has been reported previously, demonstrating the ability to produce electricity [6] and hydrogen [7,8] from the streams [9]. The impact of including BES in biorefinery process can be worthwhile due to the increased energy recovery from biomass, leading to improved energy efficiency [4], reduction in waste streams produced in the biorefinery [6], and reduction in lifecycle greenhouse gas emissions.…”

“…Candidates from each of these class of compounds have been shown to serve as substrates in the bioanode [6,19]. In addition, conversion of the whole bio-oil aqueous phase in an MEC has been recently demonstrated in our laboratory [7,20].…”

“…The MEC technology has been demonstrated at the laboratory scale as well as in small scale pilot reactors with a volumes of up to 10 L using a municipal wastewater stream. Laboratory-scale studies of two biorefinery waste streams have been reported using the proposed MEC or bioanode configurations [7,19]. Further work is necessary using the streams at pilot scale to demonstrate feasibility.…”

“…Thus, there is sufficient organic matter in the aqueous phase to produce hydrogen entirely from the biomass-derived bio-oil aqueous phase. Recent work has demonstrated a 54% overall efficiency in converting the bio-oil aqueous phase to hydrogen using MEC with a switchgrass-derived stream [7,20]. The second metric for sustainability is the amount of fossil energy used to generate biofuel.…”

Biorefinery perspectives of microbial electrolysis cells (MECs) for hydrogen and valuable chemicals production through wastewater treatment

“…complete conversion of acetic acid, propionic acid, levoglucosan, and furfural. Thus, the H2 produced from the integrated process could be utilized to hydrodeoxygenate bio-oil to produce fuel (Lewis et al, 2015).…”