Study of molybdenum–nickel alumina based catal-sorbents to simultaneously remove of H2S and NH3 from hot coal gas

Abstract

Molybdenum–nickel-based catal-sorbents were prepared with gamma-alumina (γ-Al2O3) via an impregnation (MNAI30) method, and tested for the simultaneous removal of H2S and NH3 gases in a fixed-bed reactor system. The NH3 and H2S breakthrough times of the MNAI30 catal-sorbents were 200 and 225 min, respectively. The NH3 breakthrough time was shorter than that of H2S because the NH3 decomposition ability was decreased when α- and β-NiMoO4, NiO, and MoO3 were converted into Ni3S2 and MoS2, which were ineffective in decomposing NH3 in the presence of H2 gas. NiAl2O4 was also observed in the MNAI30 catal-sorbent and was reduced during the decomposition of NH3 at a low temperature, a phenomenon that improved the NH3 decomposition ability of the catal-sorbent during the H2S absorption process.