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.

Dry Reforming of Model Biogas on a Ni/SiO2 Catalyst: Overall Performance and Mechanisms of Sulfur Poisoning and Regeneration

“…After O 2 activation, the deactivated catalyst displayed stable activity, which was recovered to exactly the level of fresh catalysts at a high temperature of 800 °C. Previously, Blanchard et al concluded similarly that catalyst activity can be completely recovered by calcining in air at 900 °C.…”

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“…Rather than incorporating Co into the mat's copper thread structure, Ma et al first coated FeCralloy woven metal fibres with MgO followed by Pt/Rh (0.01 g/g, a mass fraction of 1%) to partially oxidize methane to CO and . Blanchard et al produce syngas from —dry methane reforming—and demonstrate that can be regenerated after poisons the catalyst.…”

Catalytic activities and resistance to poisoning of tar reforming catalysts for syngas upgrading

“…Specifically, H2S, COS, HCl and HBr have been shown to cause metal corrosion and negatively affect the activity of reforming catalysts [31,32,[85][86][87][88][89][90][91][92]. The activity of Ni catalysts is also suppressed by NH3 decomposing into N2 and H2 and competing for the active sites with tar compounds [93].…”