Influence of reforming temperature on the production of hydrogen-rich syngas by staged gasification

The thermochemical gasification of ash-rich biogenic wastes is gaining increasing attention as an approach for sustainable hydrogen production and reduction of waste streams. Staged gasification processes, such as the newly by Fraunhofer UMSICHT developed Enhanced Carbon-To-X-Output (EXO) process, enable the conversion of ash-rich, hard-to-gasify biogenic residues into hydrogen-rich syngas. The EXO process is a three-stage ther mochemical conversion process, based on a two-stage gasification comprising intermediate pyrolysis and fixed- bed counter-current gasification, followed by an downstream catalytic reforming with activated carbon. The experimental investigations in this study involve the conversion of sieve overflow from biowaste by the EXO process. To study the effect of the temperature during the catalytic reforming step on gas composition and hydrogen yield, the reforming temperature is stepwise increased from 500 ◦ perature of the pilot plant is set to 450 ◦ C to 900 C, and the gasification temperature is 850 ◦ ◦ C. The pyrolysis tem C. The results show a sig nificant influence of the reforming temperature on the gas composition, which is reflected in an increase in hydrogen concentration from 26.3 vol% to 36.7 vol%. Furthermore, a significant effect on hydrogen yield, which increases from 24.72 g H2 /kg Feed,wb to 41.23 g H2 /kg Feed,wb with rising temperature, is also observed. The optimal reforming temperature of the EXO-process, based on the maximum hydrogen yield, is 900 ◦ C.