Development of a fermentation-based process for biomass conversion to hydrogen gas

The production of hydrogen gas from biomass to meet the foreseen demand arising from the expected introduction of fuel cells is envisaged. Apart from the well-known gasification method, fermentative conversion can also be applied for this purpose. Two options of the latter method, that is, thermophilic fermentation and photofermentation can be combined in a two-stage process in which about 70% of hydrogen present in biomass is converted to gaseous form. It is expected that this process can be applied in decentralized, small-scale production units. The main stages of the fermentative hydrogen production process are the following: - biomass pretreatment to give fermentable feedstock and non-fermentables, - thermophilic fermentation in which fermentable feedstock is converted to hydrogen gas and organic acids, - photofermentation in which the organic acids are converted to hydrogen gas, - upgrading of hydrogen gas to meet product specification, - separation and treatment of non-fermentables. In order to develop a sustainable hydrogen production route based on fermentation, it is necessary to improve the existing knowledge of these process stages and to carry out process optimization studies. As a major step in this direction, the European research project HYVOLUTION has been organized under the 6(th) Framework Programme of the EU.