Combined methane and ethanol reforming for pure hydrogen production through Pd-based membranes

Combined methane and ethanol steam reforming has been carried out in a conventional reformer filled with a Pt (0.5% wt.) catalyst bed. The reformer has been coupled with a multi-membrane module, where pure hydrogen has been recovered in the shell side by vacuum pumping.The experiments – that mainly aimed at measuring the hydrogen yield – have been carried out in the reaction (lumen) pressure range of 100–500 kPa, while the temperature of the reformer and the Pd/Ag membranes module has been of 760 °C and 350 °C, respectively. The water/ethanol/methane molar ratio has varied in the different experiments (10/1/0, 11/1/0.25, 14/1/1 and 26/1/4). Such water/ethanol mixtures have been investigated in order to simulate the treatment of dilute bioethanol with methane.The hydrogen yield decreases when the molar ratio methane/ethanol increases while – in presence of a high water excess (feed molar ratio water/ethanol/methane of 26/1/4) – a hydrogen yield up to 35% at 500 kPa can be achieved.

► A two-step process (traditional reformer + membrane permeator) has been tested.
► Hydrogen is produced by combined ethanol and methane reforming.
► Ultra-pure hydrogen is separated by a Pd/Ag multi-tube membrane device.
► Diluted ethanol reforming has been tested (H2O/C2H5OH/CH4 molar ratio up to 26/1/4).
► 1.8 NL/min of pure hydrogen has been collected by operating at 500 kPa.