Integration of Biohydrogen Production with Heat and Power Generation from Biomass Residues

Abstract

The employment of renewable sources rather than fossil fuels in the production of hydrogen is an important step to achieve a sustainable hydrogen economy in the future. Besides biomass gasification, production of hydrogen from renewable sources is also possible in a fermentative way through thermophilic (dark) fermentation and/or photo-heterotrophic fermentation. Depending on pretreatment procedure, considerable heat demand is necessary to produce hydrogen from agricultural residues and food processing. While heat demand in the pretreatment step can be reduced by heat integration measures, significant heat input is still necessary in the dark fermentation step. The paper evaluates possible contributions of utilizing process residues to cover the heat demand of the biohydrogen production. Process options for three types of feedstock for biohydrogen production have been investigated towards the potential of heat self-supply of the process. Results show that the heat demand of biohydrogen production from barley straw and potato steam peels can be covered from heat of biogas utilization obtained from process residues. For feedstock thick juice still a heat deficit of 0.29 MW is observed.