The production of pure pressurised hydrogen by the reformer-steam iron process in a fixed bed reactor system

Abstract

In this paper a fixed bed chemical looping process for the decentralised production of pure pressurised hydrogen for fuel cell applications is described. CH4 is converted to a syngas using conventional steam reforming. The syngas is directly used for the reduction of an iron based oxygen carrier. A consecutive oxidation step using steam leads to the formation of pure pressurised hydrogen. A thermodynamic analysis was performed in order to investigate feasible conditions for the syngas generation and reduction step. Experiments using pure hydrogen as well as an artificial syngas mixture showed the feasibility of the process for the production of pressurised hydrogen. A stable hydrogen production at a pressure of 8–11 bar(g) was achieved and only minor impurities of 700 ppm of carbon dioxide but no signs of carbon monoxide were detected in the produced hydrogen. Although the active surface decreased from 7.5 m2 g−1 to 0.9 m2 g−1 only moderate losses of reactivity were measured in the fixed bed reactor. Thermogravimetric analysis showed a loss of 9% of reactive material over nine cycles, presumably due to sintering effects.