硫代硫酸铵对 CoMo 和 NiMoP 催化剂的预硫化

 采用硫代硫酸铵预硫化 CoMo 和 NiMoP 催化剂, 考察了预硫化剂的负载量对催化剂加氢脱硫活性的影响. 对于 CoMo 催化剂, 预硫化剂含量适中, 氢气活化后脱硫活性优于硫化氢硫化的对照催化剂. 预硫化过程中产生的 SO42?可修饰 Al2O3 载体, 减弱了活性相与金属的相互作用, 这可能是催化剂活性增加的原因. 硫代硫酸铵含量过低, 导致催化剂硫化不完全, 脱硫活性下降, 而硫化剂含量过高, 使活性颗粒长大, 因而活性中心数量减少, 脱硫活性降低. NiMoP 催化剂的活性金属含量高, 不易被硫代硫酸铵充分硫化, 导致预硫化催化剂活性低于对照的 NiMoP 催化剂.

Presulfidation of CoMo and NiMoP Catalysts by Ammonium Thiosulfate

Ammonium thiosulfate ((NH₄)₂S₂O₃) was used as a sulfiding agent for presulfiding CoMo and NiMoP catalysts. The effect of the amount of (NH₄)₂S₂O₃ on hydrodesulfurization (HDS) activity was investigated. For the CoMo series, the use of a proper amount of (NH₄)₂S₂O₃ gave a higher HDS activity than when the catalyst was sulfided by H₂S. SO₄^2– formed during presulfidation modified the Al₂O₃ support and decreased the interaction between the active phase and support, and the activity was enhanced. However, a smaller amount of (NH₄)₂S₂O₃ used for the presulfidation would result in insufficient sulfidation, while a larger amount of (NH₄)₂S₂O₃ increased the particle size of the active phases, and both were harmful to HDS activity. For the NiMoP series, the presulfided catalysts were less active than those sulfided by H₂S. This was ascribed to the high metal content and the addition of P to the catalyst.