Study On Oil Catalytic Hydrodenitrogenation Strengthened By Ionic Liquids

The deep hydrogenation of nitrogen-containing compounds in oil products has been a hot and difficult research topic.The traditional hydrodenitrogenation process is achieved through high temperatures and pressures.This not only requires high energy consumption and large equipment investment costs,but also leads to many issues,such as olefin saturation,octane number drop,catalyst carbon deposition and coking.According to the characteristics of ionic liquids with special hydrogen bonds,a new catalyst-coupled ionic liquid process for hydrodenitrogenation is proposed.The effects of ionic liquids on the catalytic reaction of coupled solid catalysts were studied,and deep catalytic hydrodenitrogenation under mild conditions was achieved.The main research contents are as follows:The Ni₂P catalysts carried by six different carriers?activated carbon,silica gel,ZSM-5,MCM-41,?-Al₂O₃,SBA-15?were prepared by a double impregnation method.The catalyst activity was evaluated in a slurry reactor.The results showed that when the temperature is 210°C,the pressure is 4 MPa,and the reaction time is four hours,the nitrogen removal rate of Ni₂P catalyst supported by SBA-15 molecular sieve is the best,and the nitrogen removal rate reaches at 36%.From the information of crystal phase,structure,stability and acidity and alkalinity of different catalysts,it can be seen that the Ni₂P catalyst supported on SBA-15 molecular sieve has a large specific surface area and a large amount of acid,which are major factors in promoting catalytic hydrodenitrogenation performance.The performance of Ni₂P/SBA-15 catalyst coupling with four different ionic liquids for hydrodenitrogenation was investigated.It was found that the[BMIM]BF₄ coupled with solid catalyst exhibites the best denitrification performance,and its denitrification rate reaches at 51.2%,which is significantly higher than that of solid catalyst hydrodenitrogenation.Metal auxiliaries are screened and the loading capacity is optimized.The catalytic hydrodenitrogenation of 5 wt.%Mo-25 wt.%Ni₂P/SBA-15catalyst coupled by ionic liquid?[BMIM]BF₄?is the best.When the reaction temperature is 150°C and the pressure is 3 MPa,the catalytic denitrification activity is 80.1%.The specific surface area and pore pore size of the metal-supported Mo catalyst are the maximum,which is favorable for the diffusion of pyridine and H₂ on the surface and channels of the catalyst,thereby promoting the catalytic hydrodenitrogenation efficiency.The performance of the ionic liquid after the reaction was evaluated by four cycles of hydrodenitrogenation.The structural characteristics of the ionic liquid are basically stable,and the cyclic use performance in the catalytic hydrodenitrogenation reaction is good,and the green catalytic trait is fully exhibited.