Study On The 12-lump Kinetic Model For Residual Fluid Catalytic Cracking

Lump model is an effective method to solve kinetic problems for FCC(Fluid Catalytic Cracking)process.In this paper,the RFCC(Residue Fluid Catalytic Cracking)reaction system was classified into 12 lumps which are respectively HS(saturates),HA(aromatics),HR(resin+ asphaltene),DIESEL(diesel),GS(gasoline saturates),GO(gasoline olefin),GA(gasoline aromatics),DGAS(dry gas),L03(propylene),L04(butene),LPGD(alkane in liquefied gas)and COKE(coke)and the reaction system contains 54 virtual reaction paths according to FCC reaction mechanisms.Based on the equation of continuity and reasonable hypothesises in reaction equipment,the mathematic kinetic equation was built and was converted into Python program model where the fourth order Runge-Kutta method was used to calculate the differential equations and the BFGS method was used to optimize the target function.54 sets of kinetic parameters including pre-exponential factor k0 and activation energy E and 3 deactivation constants acquired from the program and experimental data shows a good consistence with the basic FCC reaction rules.The model also shows good reliability and extrapolation because the relative errors between the experimental values and model-calculated values for product distributions are all within 5%.Operating conditions like reaction temperature,pressure,catalyst to oil ratio and reaction time were optimized in partly combination to gain a maximum yield of primary products as diesel,gasoline,propylene and butene under certain catalyst and feedstock.Based on the above achievements,the model can be further perfected to optimize the industrial process.