Low Temperature Solid-phase Synthesis And Application Properties Of Oil-soluble Hydrogenation Catalyst In Slurry Bed

As an effective way to improve the quality of inferior heavy oil,heavy oil Slurry bed hydrocracking process will play an important role in solving the problem of low efficiency of crude oil lightness due to the world’s heavy and inferior crude oil.Aiming at the low-cost synthesis of heavy oil Slurry bed hydrocracking catalyst,this paper studies the synthesis of oil soluble molybdenum clusters by low-temperature solid-state method.The sulfurization of the catalyst and its hydrogenation performance of polycyclic aromatic hydrocarbons under the condition of slurry bed heavy oil hydrogenation were investigated.Nickel molybdenum bimetallic clusters were synthesized on the basis of single metal molybdenum clusters,and the synergistic effect of bimetallic was explored.The crystal structure of ammonium molybdate was destroyed during the low-temperature solid-state synthesis of molybdenum clusters.The molybdenum anionic clusters were combined with surfactant cations through electrostatic interaction,and finally formed a loose structure of surfactant cation coated molybdenum anionic clusters,which realized the transition of surface properties of active metal components from hydrophilic to lipophilic.The results show that the molybdenum clusters synthesized by double long chain surfactants with different chain lengths have certain oil solubility,and product synthesized by DODAC has the best oil solubility.Under the action of surfactant,the molybdenum anionic cluster can disperse uniformly in toluene and maintain good dispersion and stability in oil.In the presence of surfactant,Mo anionic clusters can disperse uniformly in toluene and keep good dispersion and stability in oil.The effect of sulfurization conditions on the formation process of Mo S₂ was investigated.The sulfurization temperature,the concentration of sulfurizing agent,the initial pressure of hydrogen sulfide and the sulfurization time significantly affected the degree of sulfidation.The crystallinity of Mo S₂ increased with the increase of sulfurization temperature and time.The number of stacking layers of Mo S₂ was related to the sulfurization temperature,sulfurization agent concentration and sulfurization time.Under the conditions of slurry bed heavy oil hydrocracking process,anthracene was used as the model reactant to investigate the hydrogenation performance of Mo S₂ under different sulfurization conditions.The Mo S₂showed the best hydrogenation selectivity at initial hydrogen pressure of 7 MPa,sulfurization temperature of 280℃,Mo:S=1:4 and sulfurization time of 30 min.The single metal molybdenum cluster was evaluated in slurry phase hydrocracking of VR at 430°C with an initial H₂ pressure of 7 MPa and the catalyst concentration of 500μg/g for 1h.It showed remarkable hydrocracking activity.Compared with the case without catalyst,the coke yield decreased from 17.45%to 0.80%,the liquid yield increased from 67.26%to 92.52%.Relative to the raw oil,the C7-asphaltene content decreased from 17.26%to 11.81%and the Saturate content increased from 12.23%to 37.46%.The size of Mo S₂ particles produced by sulfurization is mostly 4-6 nm,and most of them are monolayer structure,which is easy to expose more active centers and has higher catalytic activity.Ni Mo bimetallic bimetallic cluster were synthesized from Ni Mo binary heteropoly acid.The results showed that Ni modification inhibited the crystallization of Mo S₂ and increase the degree of sulfidation of Mo.Compared with Ni Mo bimetallic catalyst prepared by mechanical mixing method,the light oil yield of Ni modified Mo S₂ increased by 7.19%at unit coke yield.It shows a good synergistic effect.