H2S poisoning of NiAl2O4/Al2O3‐YSZ catalyst during methane dry reforming

Abstract

The objective of this work was to test resistance to hydrogen sulphide (H2S) of a recently‐patented nickel‐aluminum (Ni‐Al) spinel on Al2O3/YSZ ceramic support in catalytic reforming of methane (CH4). Previous studies showed that the catalyst is efficient for both steam reforming of complex hydrocarbons (diesel) and dry reforming of CH4. In the latter case, carbon formation was avoided for 275 h with a carbon dioxide (CO2)/CH4 ratio of 1.2. Catalytic activity was monitored at various temperatures and H2S concentrations (780–850 °C and 1.28–237 μL/L (ppmv) H2S). All tests were conducted at atmospheric pressure in a differential reactor setup. The other experimental conditions were: molar ratio 1 CO2/1 CH4/0.1 H2O, catalyst mass of 0.3 g, and gas hourly space velocity of 7000–8000 mLSTP/(gcata · h). Helium was used as the carrier gas for H2S. The NiAl2O4/Al2O3‐YSZ catalyst was loaded with nickel (Ni) 0.05 g/g (5 mass%), the Al2O3/YSZ mass ratio was 1/1, and YSZ was Y2O3‐stabilized ZrO2 (Y2O3 0.07 g/g (7 mass%)). The results showed the fastest deactivation at low temperatures and the highest H2S concentration. Catalyst activity could be partially recovered by stopping the H2S feed, and entirely recovered by calcining it at 900 °C in air. Essentially, YSZ had no effect on catalyst resistance to the presence of H2S. The catalyst gave results comparable to a commercial catalyst tested and reported in the literature.