在0到12 mL∙L-1(体积分数φ=0.00%-1.20%)范围内考察了不同H2S浓度对25%(质量分数, w) MoO3/Al2O3和5%(w) CoO-25%MoO3/Al2O3催化剂甲烷化性能的影响.结果表明,5%CoO-25%MoO3/Al2O3的甲烷化活性随H2S浓度的增加单调上升,而25%MoO3/Al2O3对H2S浓度并不敏感.对比这两种催化剂发现,只有在H2S浓度高于0.40%(φ)时,在25%MoO3/Al2O3中添加Co助剂才会有促进作用；H2S浓度低于0.40%(φ)时, Co助剂会抑制25%MoO3/Al2O3催化剂的甲烷化活性.分别对反应前后的催化剂表征发现, H2S浓度的改变不会对两种催化剂的物理结构产生明显的影响,而是通过影响催化剂表面的金属硫化物活性位来影响催化剂的甲烷化性能.耐硫甲烷化反应体系中较高的硫含量下Co助剂才表现出对25%MoO3/Al2O3催化剂的促进作用.该研究明确了在MoO3/Al2O3催化剂中添加Co助剂的硫化氢浓度范围,为工业上选择合适的催化剂提供了依据.%The activities of 25%(mass fraction, w) MoO3/Al2O3 and 5%(w) CoO-25%MoO3/Al2O3 catalysts in a sulfur-resistant methanation process were examined as the concentration of H2S was varied from 0 to 12 mL∙L-1 (volume fractionφ=0.00%-1.20%). The results showed that the catalytic activity of 5%CoO-25%MoO3/Al2O3 catalyst increased steadily as the concentration of H2S increased. However, the catalytic performance of the 25%MoO3/Al2O3 catalyst was insensitive to the H2S concentration. Co was found to benefit the 25%MoO3/Al2O3 catalyst when H2S concentration was greater than 0.40%(φ). Below this threshold, addition of Co to the catalyst matrix inhibited the activity of the 25%MoO3/Al2O3 catalyst. N2-physisorption (BET) and X-ray diffraction (XRD) analyses were used to characterize the fresh and used catalysts. The results indicated that exposure to H2S at various concentrations did not significantly affect the physical structure of the catalysts, but it wil affect the active phase through metal sulfides. The results provide the appropriate range of H2S concentration to add Co as promoter for 25%MoO3/Al2O3 catalyst, which is likely to be useful for industrial catalyst selection.
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