One interesting alternative is to combine thermophilic fermentation, producing hydrogen and acetic acid at high yields, with biogas fermentation producing methane from acetic acid. Theoretically 4 mole and 2 mole of hydrogen and methane respectively can be produced per mole glucose. Upstream to the fermentors the saccharides in the raw material (starch based) need to be made available for the thermophilic bacteria, which is done in the pretreatment. The hydrogen and methane rich product gas is purified and concentrated in the gas up-grading through an adsorption-desorption process with diethanolamine.

In this study the whole integrated Hythane from biomass production process is investigated using the commercial flowsheeting software Aspen Plus and the costing tool Aspen Icarus Process Evaluator. The model input was based on literature data as well as data obtained in lab-scale experimental work carried out by partners at Lund University. A what-if study including sensitivity analysis of important process parameters, such as productivities, yields, substrate concentration, retention times and ratio of hydrogen/methane produced will be presented.