Development Of Molecular-Level Kinetic Model And Reactor Model For Reforming

With the improvement of the accuracy of analytical techniques and the availability of advanced calculation tools,it is easy to obtain the detailed molecular composition of oil products and solve complex differential equations.Researchers gradually began to simulate the chemical conversion process from the molecular scale,and the feasibility of molecular level kinetics construction of catalytic reforming was also improved.Catalytic reforming is an important process to produce high value-added chemical products.The main products are triphenyl(benzene,toluene,xylene),hydrogen and high RON gasoline.In this paper,the reaction process of naphtha catalytic reforming is simulated from the angle of molecular combination and conversion,and the molecular scale reaction model is established to predict the product composition and its macroscopic properties,which can provide reference for energy saving and production increase in factories,which is of great significance to the optimization of catalytic reforming process.In this paper,the structural unit-bonding matrix(SU-BEM)hybrid framework is used as the modeling basis.Firstly,the refinery oil is analyzed by gas chromatography,and the molecular composition information obtained is converted into the structural unit form,and the molecular set of the model raw material is determined.Then,the petroleum molecule composition building module of CUP molecular management platform is called to get the physical and chemical properties of related molecules such as boiling point and enthalpy of formation.Then,according to the mechanism of bifunctional catalytic reaction,the reaction rules are formulated from the reaction path level,the reaction network is automatically generated by SU-BEM hybrid framework,and the microreaction kinetic model of catalytic reforming is established by adopting LHHW kinetic equation suitable for heterogeneous catalytic system.The linear free energy relation(LFER)is used to reduce the dimension of the reaction kinetic parameters,so as to achieve a balance between the complexity of the model and the computational efficiency.Then,mass balance,momentum balance and energy balance are carried out.Based on the reaction matrix in the reaction network,ordinary differential equations are automatically generated,and a molecular-scale catalytic reforming radial reactor model coupled with the microscopic reaction kinetic model is established.The changes of molecular flow rate,pressure and temperature with the radial scale of the reactor can be obtained.Taking the temperature drop of each reactor and the difference between the simulated value and the experimental value of the reactor outlet product yield as the objective function,the model is solved,and the simulation results are in good agreement with the industrial data.Finally,by changing the temperature,pressure and the ratio of hydrogen to oil,the changing trends of aromatics yield and octane number under different operating conditions are analyzed,and the obtained trends are consistent with the existing research conclusions.