CHAPTER 9: Biohydrogen and Biomethane Production

The term biorefinery refers to any industrial installation where biomass is converted into marketable energy products, so-called biofuels, and chemical intermediates or other materials of interest to industry. Due to the diverse and heterogeneous nature of biomass, a wide array of technologies is used for its transformation into specific final products. Gaseous biofuels are one category of biorefinery products. They include methane, ideally pure enough to substitute natural gas; hydrogen; and hythane fuel: hydrogen-enriched methane with less than 10% v/v hydrogen. The different technologies used to produce gaseous biofuels depend chiefly on the type of biomass to be refined and especially its water content. This chapter reviews recent advances in the catalytic processing of biomass fractions to produce gaseous biofuels. Specifically, catalytic aqueous-phase reforming (APR), catalytic supercritical water gasification (SCWG), and the production of biosynthetic natural gas (Bio-SNG) by catalytic hydrogenation of carbon oxides (CO/CO₂) from biomass streams.