Study On The Catalyst For Selective Ring-opening Of Decalin

For the evaluation criteria of diesel oil based on the cetane ratio,the density and aromatics content of inferior diesel have been increasing year by year.In the FCC diesel components,the cetane ratio is much lower,the density is biger,and the stability is poorer.By preparing a catalyst with selective hydrogenation and ring opening,the selective opening of the double-ring compounds in diesel to alkyl-alkyl compounds or alkanes is an effective way to remove aromatics.In this paper,catalyst was prepared by impregnating and mixing Ni-Mo composite oxide and USY zeolite-Al₂O₃.The results show that the catalytic cracking process of decalin is very complex,which mainly involves a series of competitive reactions such as isomerization,hydrogen transfer,alkyl transfer and cracking,and the opening ring reaction begins after a certain degree of isomerization,and the ring opening reaction mainly follows the mechanism of positive carbon ionization.The best process conditions were selected that the best temperature is 300°C,the best pressure is 3Mpa,the best ratio hydrogen to oil is 300,and the best space velocity is 1.0h^-1.Secondly,the hydrocracking products of decalin on the catalyst with different acid content was investigated.The results showed that the suitable acid strength and acid content could increase the yield of decalin ring products.The acid too weak acidity would cause the reduction of the decalin isomerization and the conversion rate,and the too strong acid would lead to the two times of the ring opening products.Cracking is a light component,which is not conducive to increasing the yield of ring opening products.In the end,the K element was introduced to modify the catalyst,which weakened the strong acid position to a certain extent and reduced the selectivity of decalin to the light component by two decomposition of naphthalene,and improved the yield of the open ring product.