Research On The Diesel Oil Hydrofining Catalyst Carrier Ultrafine Y/Al₂O₃ Composite Material

In this paper, a systematic study on the ultrafine NaY zeolite synthesis, inspected the inf- luence of many factors such as crystallization temperature, crystallization time, surfactant co- ntent, low gel temperature and gel aging. Under the best sythesis conditions: gel 2 hours at low-temperature 8℃, gel aging 10 hours at 50℃, crystallize 20 hours at low-temperature90℃, the added amount of cetyltrimethylammonium bromide is 0.6 CMC, as a result, the crystalline of the synthesized NaY zeolite is perfect , and its grain size is between 150 and 250 nm. The zeolite skeleton structure, specific surface area and pore structure, and acidity and thermal sta- bility of ultrafine NaY zeolite were characterized by IR, XRD, BET, NH3-TPD, and TG-DTA methods. The results showed that, compared with conventional NaY zeolite, skeleton structu- re and pore structure of ultrafine NaY zeolite are similiarly same, and its surface area is lower, but its thermal stability is good.In this paper, the ultrafine NaY/Al2O3 composite material was prepared by sol-gel meth- od. And citric acid was added into the composite material as a reaming agent. In this work another three different contrast carrier materials were also prepared. The skeleton structure, specific surface area and pore structure, and acidity of composite material were characterized by IR, XRD, BET, NH3-TPD methods. The results showed that, the composite material is a mesoporous-microporous composite material; and its surface area is 321 m2/g, pore volume is 0.73 cm3/g, average pore diameter is 9.1 nm; and it mainly has weak acids.A kind of catalyst was prepared, ultrafine NaY/Al2O3 composite material was used as ca- rrier and active component Ni-Mo-P was supported on the carrier. The catalyst phase, dispers- ion of active ingredients, specific surface area and pore structure, and acidity of catalysts were characterized by IR, XRD, BET, NH3-TPD methods. The catalytic performances of prepared catalysts were evalued by a fixed-bed micro-reactor using diesel oil as stock oil. The results showed that, the catalyst mainly has weak acid-site; and compared with the contrast catalyst CK-2, their acidity, specific surface area, porediameter and pore volume are similarly same; but when adding reaming agent, the specific surface area, pore volume and porediameter are increasing, and the active components on the catalyst surface scatter better.The evaluated results showed that, the catalysts with composite material as carrier have higher HDS, HDN and aromatics saturation activity, and compared to contrast catalyst CK-2, its HDS activity is higher, but its HDN activity is somewhat lower, and the diesel oil yield is higher. for example: under the reaction conditions: temperature 370℃, pressure 4.0 MPa, space velocity 1.0 h-1, hydrogen oil ratio 500/1, the HDS rate, HDN rate and increased cetane number of the hydrogenation catalyst is 98.2 %, 95.2 %, 12.9units, this catalyst was prepared with composite material and reaming agent.