工艺条件对耐硫变换催化剂COS转化活性以及甲硫醇生成量的影响

模拟工业装置的工艺条件,考察了原料气中CO和H2S含量、温度和水气比等因素对耐硫变换催化剂COS转化活性和甲硫醇生成量的影响。结果表明,当原料气中CO和H2S含量较高时,会有甲硫醇生成,且其生成量随着CO和H2S含量增加而增加;受平衡的影响,原料气中H2S含量升高时,COS转化率降低;增加反应温度,可以提高COS的氢解反应活性,并减少甲硫醇的生成,但不利于COS的水解反应。水气比具有提高COS转化活性并减少甲硫醇生成的双重作用:水气比较低时,其值从0增加到0.2,COS转化率从89.65%增加到97.82%,表明COS的水解反应比氢解反应更容易进行;当水气比为0.3时,反应后的尾气中只有微量甲硫醇生成,当水气比大于0.4时,反应后几乎无甲硫醇生成。

Impacts of Process Conditions on the COS Conversion and CH3SH Formation of Sulfur-tolerant Water Gas Shift Catalysts

The impacts of CO and H2S concentrations in feedstock,reaction temperature and water(steam)/gas ratio on the COS conversion and CH3SH formation of sulfur-tolerant water gas shift(SWGS)catalysts were examined based on reactions simulating the real process conditions of industrial plants.The results showed that the formation of CH3SH which required high concentrations of CO and H2S to start could be further promoted by higher concentrations of CO and H2S.The COS conversion decreased with the increase of H2S concentration in feedstock due to the reaction equilibrium.Raising reaction temperature helped COS hydrogenolysis and prohibited CH3SH formation;however,the COS hydrolysis was somehow suppressed.Water/gas ratio had important influences on both COS conversion and the suppression of CH3SH formation.The water/gas ratio could play a dual role in improving COS conversion and reducing CH3SH formation:when there was a relatively lower water/gas ratio if its value was increased from 0 to 0.2,COS conversion would increase from 89.65%to 97.82%,showing COS hydrolysis was more active than hydrogenolysis for SWGS catalysts.When water/gas ratio was 0.3,there was only trace amount of CH3SH formed in the tail gas after reaction;when it was greater than 0.4,there was almost no CH3SH formation after reaction.