Study On The Catalyst And Process For Hydrotreating Of FCC Slurry Oil

The fluid catalytic cracking(FCC)plant is the largest heavy oil secondary converter in China,and produces mass of high-density,high-sulfur,high-nitrogen slurry oil.FCC slurry oil is rich in hydrocarbons with aromatics of two to four which is high-quality material for producing high value-added carbon materials and has high potential application value.In view of which the slurry oil contains unstable olefins and alkenyl arene,a little catalyst fine powder and high content of polycyclic aromatics.The slurry bed hydrotreating pretreatment process is proposed,and oil-soluble and supported microsphere catalyst are supporting developed,preliminary formation of FCC slurry oil hydrotreating pretreatment technology.The oil-soluble Mo-based catalyst was prepared by two-step reaction of organic solvent and sulfur-containing molybdenum salt,and the process conditions of FCC slurry oil hydrogenation reaction were optimized.The results show that the oil-soluble Mo-based catalyst has good oil solubility and decomposed with self-sulfidation into nano-dispersed high-activity Mo S₂ particles during heating.Using Qingdao Refining FCC slurry oil as material,under the condition of reaction temperature of 400°C,hydrogen initial pressure of 10 MPa,catalyst concentration of 1000?g·g^-1,reaction time 2 h,a little olefin and alkenyl arene can be effectively removed.The saturation of diene reached 90.4%.In addition,the catalyst has a certain degree of weight reduction of the FCC slurry oil,hydrogenation saturation of the four and five aromatic hydrocarbons,and sulfur-nitrogen hetero atom removal performance.At the same time,the slurry bed hydrotreating pretreatment process can promote the agglomeration of the catalyst fine powder particles contained in the FCC slurry oil,and the particle size of the solid content increases.The proportion of particles with particle size<10?m is reduced from 28%to 7%.It facilitates the clean separation of subsequent solids.The supported Ni Mo catalyst was prepared by using micron-sized microspheres as carrier.The effect of carrier calcination temperature on the hydrogenation performance of the catalyst was investigated.The results show that the catalyst has the best pore structure and surface acidity when the calcination temperature is 550°C.It is suitable for the diffusion of the constituent molecules of the slurry and is beneficial to the dispersion of the active components which has the highest FCC slurry oil hydrotreating performance.Under the conditions of reaction temperature of400°C,hydrogen initial pressure of 10 MPa,catalyst addition of 5 wt%and reaction time of 2 h,the saturation of diene reached 93.6%.The dienes which was extremely unstable to heat is efficient removal.Since the catalyst is dispersed in the micrometer range,it is very easy to recover,which is beneficial to the recycling of the catalyst.The multi-batch kilo-scale amplification mass production of oil-soluble Mo-based catalyst was completed,and the pilot performance evaluation of continuous slurry bed hydrogenation was carried out with Jingbo FCC slurry oil.The results show that the oil-soluble Mo-based catalyst has high yield,reproducible strength and excellent dispersibility.The evaluation device runs smoothly,the suitable reaction conditions are:reaction temperature of 410°C,pressure of 16 MPa,catalyst concentration of 1000?g·g^-1,space velocity of 0.4 h^-1,hydrogen to oil ratio 500/1,After hydrogenation,the saturation of diene reached 90.7%,which significantly improved the thermal stability of the FCC slurry.The proportion of particle size<10um particles decreased from 36%to 9%,and the particle size of the solid content increases,which was beneficial to the long-term operation of the subsequent filtration de-solidification device.