Natural gas steam reforming reaction at low temperature and pressure conditions for hydrogen production via Pd/PSS membrane reactor

Abstract

The objective of this work is to analyze the performance of a composite palladium-based membrane reactor (MR) by performing the natural gas steam reforming reaction at low operating conditions for producing high-purity hydrogen. The MR comprises a composite membrane, having ~13µmPd layer deposited on a porous stainless steel support, fabricated via electroless plating and a commercial Ni-based catalyst.The composite membrane shows infinite ideal selectivity, H2/He and H2/Ar, at trans-membrane pressures less than 100kPa and T=400°C at the onset of experimental testing. The steam reforming reaction is performed at 400°C, by varying the reaction pressures and sweep gas flow rate between 150kPa and 300 kPa, and 0–100mL/min, respectively. The gas hourly space velocity (GHSV) and steam-to-carbon ratio (S/C) are kept constant at 2600h−1 and 3.5.The effect of CO2 as an impurity in the feed line is also analyzed at 400°C and 150kPa.The best performance of the Pd-based MR is obtained at 400°C, 300kPa and 100mL/min of sweep-gas, yielding a methane conversion of 84%, hydrogen recovery of 82%, and obtaining a pure hydrogen stream at the permeate side.The Pd/PSS MR worked for more than 700h under differing operating conditions. As a comparison, a conventional reactor operating at the same MR conditions is compared and discussed.