论文部分内容阅读
用全硅MCM-41担载Ni-Mo双金属活性组分制备了高活性加氢脱硫催化剂,并考察了其对二苯并噻吩(DBT)、4-甲基二苯并噻吩(4-MDBT)、4,6-二甲基二苯并噻吩(4,6-DMDBT)和高硫直馏柴油加氢脱硫反应的活性。结果表明,所研制的催化剂对DBT、4-MDBT、4,6-DMDBT和高硫直馏柴油(w_S=2.83％)均具有很高的加氢脱硫活性。该系列催化剂的最佳Ni/Mo原子比为0.75,高于以γ-Al_2O_3作载体的传统Ni-Mo催化剂的最佳原子比。在DBT的加氢脱硫反应中,双组分催化剂低温下(<300℃)生成环己烷基苯(CHB)的选择性高于联苯(BP),与MoO_3/MCM-41的产物分布不同。随着温度的升高,CHB的选择性显著下降,而生成苯和环己烷的选择性显著提高,说明裂解产物主要由CHB分解而得。由TPR谱图可知,Mo和Ni活性组分在表面存在相互作用,从而使得氢耗特征温度发生变化。在Ni/Mo原子比为0.75时,TPR谱上出现4个特征峰,说明Mo和Ni的配伍性和协同作用对于提高催化剂活性很重要。
Highly active hydrodesulfurization catalysts were prepared by loading Ni-Mo bimetallic active components with all-silicon MCM-41. The catalytic activity of dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT ), 4,6-dimethyldibenzothiophene (4,6-DMDBT) and hydrodesulfurization of high-sulfur straight-run diesel. The results show that the catalysts have high hydrodesulfurization activity for DBT, 4-MDBT, 4,6-DMDBT and high-sulfur straight-run diesel oil (w_S = 2.83%). The optimal Ni / Mo atomic ratio of this series of catalysts is 0.75, which is higher than that of the conventional Ni-Mo catalyst with γ-Al 2 O 3 as carrier. In the hydrodesulfurization of DBT, the selectivity of two-component catalyst to cyclohexane-based benzene (CHB) is higher than biphenyl (BP) at low temperature (<300 ℃), which is different from the product distribution of MoO_3 / MCM-41 . With the increase of temperature, the selectivity of CHB decreased significantly, while the selectivity of benzene and cyclohexane was significantly increased, which indicated that the pyrolysis products were mainly decomposed by CHB. From the TPR spectrum, it can be seen that there is interaction between Mo and Ni active components on the surface, so that the characteristic temperature of hydrogen consumption changes. When the atomic ratio of Ni / Mo is 0.75, there are four characteristic peaks in the TPR spectrum, indicating that the compatibility and synergism between Mo and Ni are important to improve the catalytic activity.