Purification of H2-rich gas from methanol reformer by preferential oxidation over Pt-Ru/Al2O3 catalyst

A methanol reformer with a purification system was designed and investigated in this study. Hydrogen was produced by ATR (auto-thermal reforming), and reformate gas was purified by WGS (water gas shifting reaction) and PrOX (preferential oxidation). The investigated parameters were GHSV (gas hourly space velocity) and O₂/CO (oxygen/carbon monoxide molar ratio). Experimental results showed that hydrogen concentration was 28.52% and carbon monoxide concentration was 7.67% in hydrogen-rich gas from ATR reformer. Through the water gas shifting reactor, CO concentration was as low as 0.81%. The improvement of CO was 98.58% under the GHSV=7800 h^-1 and O₂/CO=1.44. The reformate gas sampled in the outlet of preferential oxidation reactor, CO concentration was measured as low as 12 ppm at GHSV=3900 h^-1. The overall H₂ flow rate of 23.24 L/min could be supplied for the requirement of a 1.5 kW fuel cell system. By performing a 4-hour stability test, the CO could be controlled around as low as 50 ppm, and H₂ concentration could be maintained at approximately 32%-33%.