Methane steam reforming in a membrane reactor using high-permeable and low-selective Pd-Ru membrane

We performed a methane steam reforming (MSR) reaction through a membrane reactor packed with commercial Ni/Al2O3 catalyst and a tubular Pd-Ru membrane deposited on a YSZ modified porous stainless steel support under mild operating conditions: 773 K and a pressure difference range of 100-250 kPa. We prepared the Pd-Ru membrane with thickness of similar to 6 mu m on a tubular stainless steel support (diameter 12.7mm, length 25 cm) using electroless plating, which was observed for the membrane performance using hydrogen and nitrogen. Gas permeation test carried out at 773 K and 31.4 kPa of pressure difference between retentate and permeate sides showed that the hydrogen permeation rate and nitrogen leakage were similar to 0.1050mol s(-1) m(-2) and similar to 0.0018 mol s(-1) m(-2), respectively. The MSR reaction was under the following conditions: temperature 773 K, pressure 100-250 kPa, gas hourly space velocity (GHSV) 837 h(-1), and steam-to-carbon feed ratio (S/C) 3. The MSR reaction result showed that methane conversion was increased with increasing pressure difference and reached similar to 77.5% at 250 kPa. In this condition, the composition of carbon monoxide was similar to 2%, meaning that no two series of water gas shift reactors were needed in our membrane reactor system. Longterm stability test carried out for similar to 100 h showed that methane conversion and the hydrogen yield remained constant

Palladium/ruthenium composite membrane for hydrogen separation from the off-gas of solar cell production via chemical vapor deposition

The potential application of palladium-ruthenium composite membranes to the separation of hydrogen from chlorosilane gases in silicon-based industries was investigated. Palladium and palladium-ruthenium composite membranes were deposited on pretreated porous stainless steel substrates by electroless plating. Hydrogen permeation tests and temperature programmed desorption (TPD) analysis revealed that the addition of a Ru overlayer on Pd changed the hydrogen adsorption characteristics, resulting in improved stability of the membrane at low temperatures. The Ru/Pd/Al2O3/PSS composite membrane had a stable hydrogen permeation flux of 1.8 m3 m−2 h−1 over a period of 1200 h at 180 °C without suffering hydrogen embrittlement. After exposure to impurities such as HCl and SiHCl3, the hydrogen permeation flux of the Ru/Pd/Al2O3/PSS composite membrane was stable over a period of 9 h with feed pressure of 2.0 bar at 225 °C. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and EDX mapping of the Ru/Pd/Al2O3/PSS membrane after the exposure test showed no surface deposition of Si and Cl