Modification Of Alumina Carrier And Its Influence On Residue Hydrotreating Catalyst

The paper is a part of major program which is developing residue hydrotreating catalyst of petro chemical research institute of petro China (Beijing). Residue hydrotreating technology is an effective manner of treating residue. People need to exploit new residue catalysts. Physicochemical properties and catalysis properties of the catalysts should be better improved. In today's condition, the catalysts should meet the demand of industry production and produce eligible oil products.The paper systematically investigated peptizer, expanding agent, drying type, roasting temperature and other factors in the preparation of alumina carrier. The study found that chemical composition of the material with the same system, not the same peptizer, carrier pore structure and bulk density significantly changed. The bulk density of carrier with the amount of peptizer increasing becomes larger. With the roasting temperature inreasing, surface area of carrier reduced, pore volume slightly decreased, the pore size distribution increased gradually. Fast drying manner of the carrier has lower bulk density and higher water absorption. Adding expanding agent can significantly increase the pore volume of carrier.The paper also examined carrier phase, pore structure, acidity and alkalinity properties with different system type and different amount of agents in the alumina. The study found that the introduction of agent A and B do not change the alumina carrier phase, but have greater impact on the pore structure and acidity of carrier. With the agent A content increasing the specific surface area of the carrier increased, the most probable pore size and pore volume decreased. With the agent B content increasing the carrier surface area and pore volume decreased, the most probable pore size tended to increase. Adding the agent A can reduce B acid, but place less influence on the amount of L acid and total acid content. Agent B can significantly increase the amount of acid B, with the content of agent B increasing, the amount of B acid increased, the amount of L acid reduced, the amount of total acid decreased firstly, and then increased. Compared to the agent A, adding small amount of the agent B can effectively control B acid and L acid of carrier.The paper also prepared residue hydrotreating catalysts modified by agent A and B. Using XRD, BET, Py-IR, ICP, XPS and other methods to characterize their physical and chemical properties. Catalyst sample phase, pore structure, acidity and alkalinity properties were studied with different type and amount of agents. The study found that with the agent A content increasing, the catalyst surface area increased, pore volume decreased. With the agent B content increasing, the catalyst surface area and pore volume decreased. The agent A has little effect on the L acid of catalyst, and the amount of B acid decreased slightly. The agent B could significantly reduce the amount of L acid, and the amount of B acid increased slightly.The paper estimated catalyst activity and stability in the fixed-bed hydrotreating device. Compared with the modified catalyst by agent A and REFC, modified catalyst by the agent B has more activity of getting rid of impurities. Long-period stability of the evaluation showed the stability of modified catalyst by the agent B is superior. Introducing 0.3%-1.8%mass content of the agent B into the alumina can make the modified residue hydrotreating catalyst with better performance be prepared.