关键词: 失活, 催化剂, 稳定性, 天然气, 耐硫甲烷化, 桥键 {\mathrm{S}}_{\mathrm{2}}^{\mathrm{2}-} 物种, 硫流失

Abstract:

The MoS₂/Si-ZrO₂ catalyst was prepared by an equal volume impregnation method, and the catalytic activity stability of CO for sulfur-tolerant methanation was evaluated. The CO conversion of the MoS₂/Si-ZrO₂ catalyst decreased by 11% under the following condition: molar ratio of feed gas composition was 2H₂∶2CO∶1N₂; concentration of H₂S was 0.01%; weight hourly space velocity was 6000 ml/(g·h); reaction temperature was 450℃ and reaction pressure was 2.5 MPa. The catalysts were further characterized by hydrogen temperature programmed reduction (H₂-TPR), X-rays photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), Raman spectra (RS), inductively coupled plasma emission spectra (ICP-OES), thermogravimetric analysis (TGA) and elemental analysis. The results demonstrated that little carbon deposited on the surface of spent catalyst, which did not cause catalyst deactivation. The minor cause was that MoS₂ slabs grew longer and stacked more layers after long-term reaction and then covered the active sites. The root deactivation cause was attributed to parts of catalytic active bridging {\mathrm{S}}_{\mathrm{2}}^{\mathrm{2}-} ^{species converting to less active S2- species and H₂S, which resulted in the loss of active sites and sulfur element.}

Key words: deactivation, catalyst, stability, natural gas, sulfur-resistant methanation, bridging {\mathrm{S}}_{\mathrm{2}}^{\mathrm{2}-} ^species, sulfur loss