| Summary: | Low-temperature hydrogen production from natural gas via steam reforming requires novel processing concepts as well as stable catalysts. A process using zeolite membranes of the type MFI (Mobile FIve) was used to enrich natural gas with liquefied petroleum gas (LPG) alkanes (in particular, propane and <i>n</i>-butane), in order to improve the hydrogen production from this mixture at a reduced temperature. For this purpose, a catalyst precursor based on Rh single-sites (1 mol% Rh) on alumina was transformed in situ to a Rh1/Al<sub>2</sub>O<sub>3</sub> catalyst possessing better performance capabilities compared with commercial catalysts. A wet raw natural gas (57.6 vol% CH<sub>4</sub>) was fully reformed at 650 °C, with 1 bar absolute pressure over the Rh1/Al<sub>2</sub>O<sub>3</sub> at a steam to carbon ratio S/C = 4, yielding 74.7% H<sub>2</sub>. However, at 350 °C only 21 vol% H<sub>2</sub> was obtained under these conditions. The second mixture, enriched with LPG, was obtained from the raw gas after the membrane process and contained only 25.2 vol% CH<sub>4</sub>. From this second mixture, 47 vol% H<sub>2</sub> was generated at 350 °C after steam reforming over the Rh1/Al<sub>2</sub>O<sub>3</sub> catalyst at S/C = 4. At S/C = 1 conversion was suppressed for both gas mixtures. Single alkane reforming of C<sub>2</sub>⁻C<sub>4</sub> showed different sensitivity for side reactions, e.g., methanation between 350 and 650 °C. These results contribute to ongoing research in the field of low-temperature hydrogen release from natural gas alkanes for fuel cell applications as well as for pre-reforming processes.
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