Modified Alumina Reaming And Hydrogenation Desulfurization Performance Research

Catalyst support play an important role not only in loading active component but also in improving catalyst selectivity, heat transfer, catalyst service life and decreasing the production costs. At present, the common hydrogenated catalyst supports used in industry is γ-Al2O3, With the disadvantages of the low pore volume and small specific surface area, developing the microporous Al2O3 support with appropriate pore distribution is necessary,γ-Al2O3 was prepared with 2 different methods at first, and then the best pore structure was selected by charactering and analyzing as the subsequent support. γ-Al2O3 was treated by adding pore-expanding additives and hydrothermal treatment respectively to study the effects of hydrothermal solvent, hydrothermal time, hydrothermal temperature and the types of pore-expanding agent on the. pore structure of γ-Al2O3. Combined with hydrothermal treatment method and pore-expanding additives method, hydrodesulfurization catalyst was prepared with 4 different structures. With the micro fixed bed reactor as the catalyst activity evaluation device, the effects of reaction temperature, pressure as well as liquid space velocity and hydrogen-oil ratio on thiopHenic sulfur were studied. The results of the studies are listed as follows:Characterized and analyzed by XRD, FT-IR,SEM and BET, we find that γ-Al2O3 which is prepared by isopropyl alcohol aluminum hydrolysis method has higher crystallinity, better look, larger specific surface area and appropriate pore size (5-15 nm) than the γ-Al2O3 which is prepared by homogeneous precipitation method.Hydrothermal solvent have a significant effect on the pore structure of the γ-Al2O3 support. At different hydrothermal environment, we find that the pore volume of γ-Al2O3 support sorted in ascending order is deionized water<citricacid solution< ammonium bicarbonate solution. The average pore diameter sorted in ascending order is citricacid solution<deionized water< ammonium bicarbonate solution. After 9 hours treatment by 0.08 mol/L ammonium bicarbonate solution at 100℃, the pore volume of the samples are 0.69 ml/g, the pore size is 28.3 nm, the proportion of pore volume which is at 20-50 nm is 71.5%.Different pore-expanding agents have different effects. Microporous activated carbon, methycellusose and starch have bad pore expanding effect on microporous, which is more than 50 nm. Starch had better pore-expanding effect on the pore which is at 5-20 nm. Activated carbon is the best of the three. The average pore size is 18.6 nm, the proportion of pore volume which is at 5-50 nm is 89.5%.Hydrodesulfurization catalyst is prepared by γ-Al2O3 supports with 4 different structures. The hydrogenation desulfurization experiment is done as the probe reaction to investigate the performance of the catalyst. The result shows that, γ-Al2O3 which is prepared by pore-expanding agent method and hydrothermal treatment method has the best thiopHenic sulfur removal rate loading CoMo active component. The optimized conditions are:Tempreature:300℃, Pressure:5 MPa, liquid space velocity:2 h-1, hydrogen-oil ration:600:1.