Upward Residue Hydrogenation Catalyst And Performance Evaluation

During the hydrogenation reaction of residual oil,the catalyst is easily deactivated,the reason of deactivation is attributed to coking and metal deposition in the catalyst.It is necessary to study the properties of the catalyst and reaction conditions in order to improve the hydrogenation activity and operating cycles of the catalyst.At the first,the thesis characterized upward residue hydrogenation catalyst by using chemisorption analyzer,NH₃-TPD and Py-IR,etc.Results showed that pore structure of the catalyst was gradient distribution and has large pore volume,the active component content is7.2%,weak acid is dominant and the content of B acid is few,the content of Mo S₂which slab length is 2-3 nm is mostly and the number of single stacked layers is mainly.The effects of reaction conditions on hydrogenation,carbon deposition and metal deposition of residual oil showed that increased the reaction temperature,pressure and time are all can intent the carbon removal rate and metal removal rate.The influence of reaction temperature and pressure is more significant than that of reaction time.The carbon content is the largest when the reaction temperature is 390°C and the amount of hard carbon increased with the improve of reaction temperature.The amount of carbon deposition is negatively correlated with the reaction pressure.The amount of soft carbon and hard carbon are all reduced with the improve of reaction pressure.The prolongation of reaction time is beneficial to coking,the content of hard carbon is gradually increased and the content of soft carbon is gradually reduced with the reaction time prolonged.The type of distribution of metal vanadium which in the catalyst are all V-shaped,while metal nickel is shallow U-shaped.The order of the influence of reaction conditions on the uniformity of metal distribution is as follows:reaction pressure>reaction temperature>reaction time.The catalysts were modified by phosphorus and EDTA to investigate the effects of phosphorus content and addition order on the properties of catalysts.The results showed that B acid appeared on the surface of the catalyst after adding phosphorus and the content of it increased with the intent of P/Mo.At the same time,the amount of total acid,weak acid,medium acid are all increased with P/Mo intended,the proportion of multiple layers of active phase stacking and the average number of stacking layers are all increased,and A₇was the largest.Mo S₂slab length first increasing and then decreasing along P/Mo increased,and A₅is longest.The result shows that the hydrogenation and volume carbon of A₆is the strongest.The staking numbers of Mo S₂slabs,slab length of Mo S₂and the amount of acid of catalyst which prepared by two-step impregnation are all smaller than the catalyst which prepared by co-impregnation,the difference between the catalysts which prepared by two-step impregnation is not obvious.The number of active phase stacking layer of catalyst which modified by EDTA-phosphorus was significantly higher than that of catalyst which modified by phosphorus and B₁is highest,while Mo S₂slab length decreased with the content of EDTA increased,the amount of acid first increasing and then decreasing.The experimental result shows that the catalyst which is B₁has the best effect of residue hydrogenation and pore volume loss rate was the lowest,the ability of anti-coking and volume carbon is the strongest.