助剂对 Co-Mo／γ-Al2O3催化剂加氢脱硫反应氢耗的影响

摘要

The hydrodesulfurization of 4 ,6‐dimethyldibenzothiophene was studied in the presence of 1‐methylnaphthalene in order to investigate the influence of the n(Co)(Co + Mo) in Co‐Mo/γ‐Al2 O3 catalyst on the activity of the catalyst ,and the selectivity and hydrogen consumption in hydrodesulfurization .The oxidic Co‐Mo/γ‐Al2 O3 were characterized by H2‐TPR ,XRD ,Raman and the sulfided Co‐Mo/γ‐Al2O3 were characterized by TEM ,XPS .The results indicated that when n(Co)(Co + Mo ) equaled to 0.3 , the metal‐support interaction in the oxidic catalysts was weakest ,the proportion of the Co‐Mo‐S phase in the sulfide catalyst and the sulfidation degree reached the highest level ,and the average length of the MoS2 slabs was shortest .Accordingly ,the activity and the direct desulfurization selectivity reached the maximum , w hereas the average hydrogen consumption of one mole removed sulfur and the average hydrogen consumption of the aromatics of one mole removed sulfur reached the lowest level .The type of the active phase and especially the amount of the Co‐Mo‐S phase were the important factors affecting the activity , selectivity and the utility efficiency of the hydrogen .%以4，6‐二甲基二苯并噻吩与1‐甲基萘的混合体系为对象，考察Co‐Mo／γ‐Al2O3催化剂中 n（Co）／n（Co＋Mo）对其催化加氢脱硫反应的加氢脱硫活性、加氢脱硫选择性、芳烃饱和活性以及反应氢耗的影响，并采用 H2‐T PR、XRD、Raman、TEM 、XPS等表征手段对催化剂进行分析表征。结果表明，当 n（Co）／n（Co ＋ Mo）为0.3时， Co‐Mo／γ‐Al2 O3中金属组分与载体间相互作用力最弱，硫化态催化剂Co‐Mo‐S相的比例、活性金属Mo的硫化度最高， M oS2片晶的平均长度最短。相应地，该催化剂的加氢脱硫活性、加氢脱芳活性、直接脱硫选择性达到最高值，同时脱除每摩尔硫的氢耗、脱除每摩尔硫时芳烃饱和反应的氢耗均最低，即H2利用率最高。活性金属存在形态特别是Co‐M o‐S活性相数量是影响催化剂加氢脱硫活性、加氢脱芳活性、加氢脱硫选择性以及H2利用率的重要因素。