Hydrogenation Of Naphthalene On Ni₂P/AC Catalyst And Influences Of Nitride And Sulfide

With the increasing demand of the oil, the crude resource has been in short supply in modern times. People are keeping trying to find the substitute of crude oil, coal tar and shale oil are the most promising with the similar property with natural crude. But the high contents of aromatic compounds limit their application, and hydrogenation process is the most effective method to remove aromatics. Of all the aromatic compounds, the content of naphthalene is the highest. Naphthalene is an important raw material for synthetic resins and dyes. Decalin is one of the products from naphthalene hydrogenation and it can be used to an ingredient of jet fuel. Tetralin is a partially hydrogenated product of naphthalene, it is also the best hydrogen-donor solvent in direct coal liquefaction, and it can be used as a variety of industrial solvents, too. So it is obviously significant to develop the best process conditions and catalyst with good performance in naphthalene hydrogenation.In the current hydrogenation catalyst investigation, transition metal phosphide has excellent performance in HDS and HDN. but the research of its performance in hydrogenation of aromatics is limited. Nickel phosphide catalyst supported on activated carbon was prepared to investigate its catalytic performance in naphthalene hydrogenation with a comparison to silica-supported nickel phosphide, and the influences of quinoline and thiophene. The contents and results as follows:Ni2P/AC and Ni2P/SiO2were prepared by in-situ reduction method. Naphthalene hydrogenation performance was studied in a fixed-bed continuous reactor to examine the chemical reaction networks and the influences of different loading of Ni2P, temperature, pressure. H2/liquor ratio and space velocity. The experiments proved that naphthalene hydrogenation is a consecutive reaction. The path is tetralin first and then decalin(trans-and cis-). Ni2P/AC with30wt%loading has the best performance. The optimum condition is340℃、4MPa, H2/liquor ratio of500ml/ml with naphthalene convertion of95%. tetralin selectivity of91.87%, trans-decalin selectivity of6.72%and cis-decalin selectivity of1.41%. Performances on Ni2P/SiO2include naphthalene convertion of98.29%, tetralin selectivity of33.05%, trans-decalin selectivity of53.36%and cis-decalin selectivity of13.59%under the same condition. Ni2P/AC is the better catalyst to produce tetralin for hydrogen-donor solvent in direct coal liquefaction. Quinoline has a strong competitive adsorption with naphthalene on Ni3P/AC. The presence of quinoline has a negative effect of naphthalene conversion and an inhibition effect of tetralin hydrogenation. Quinoline makes the hydrogenation process delay under every reaction conditions. The adsorption of quinoline on NiiP/AC is reversible. Ni2P/AC has a good nitrogen-resisting property.The adsorption of thiophene on Ni2P/AC is partially irreversible. The adsorption of thiophene on Ni2P/AC can easily make a new Ni-P-S phase. The presence of thiophene makes a negative influence of Ni2P/AC.