Kinetics Of Vacuum Gas Oil Catalytic Cracking

Catalytic cracking is an important production process used in the production of gasoline,diesel and LPG.For the needs of the market,State Key Laboratory of Heavy Oil developed a prolific gasoline catalytic cracking catalyst.Use Daliya VGO and Penglai VGO as feedstock,the paper studies on Catalytic Cracking law and FCC reaction kinetics.The paper first uses Daliya VGO and Penglai VGO as feedstock,catalyst A or B made by State Key Laboratory of Heavy Oil Processing was used,the effects of reaction temperature,catalyst-oil ratio,weight hourly space velocity and water-oil ratio on the product yields and distribution were studied in a confined fluidized bed reactor.A and B both show high quality of catalytic effect.Catalyst B is a little better than catalyst A in cracking property and Daliya VGO is better than Penglai VGO.Under the operating conditions of the reaction temperature 500 °C,the ratio of catalyst to oil 6,weight space velocity of 20 h-1,the ratio of water to oil 0.08,use Daliya VGO as feedstock and catalyst B was used,the conversion rate is 90.14%,the liquid yield is 73.15% and the light oil yield is 84.93%.when use Daliya VGO as feedstock and catalyst B was used,the optimal operating conditions of the reaction are temperature 490 °C,the ratio of catalyst to oil 6,weight space velocity of 20 h-1,the ratio of water to oil 0.08,the conversion rate is 90.50%,the liquid yield is 85.86% and the light oil yield is 75.75%.when use Penglai VGO as feedstock and catalyst B was used,the optimal operating conditions of the reaction are temperature 480 °C,the ratio of catalyst to oil 6,weight space velocity of 20 h-1,the ratio of water to oil 0.08,the liquid yield is 81.73% and the light oil yield is 74.10%.Then the paper establishes FCC seven lumped kinetic mode,FCC eight lumped kinetic model,FCC eleven lumped kinetic model and obtains 68 different product distributions under different temperatures and weight space velocities.The rate constants at 480 °C,500 °C,520 °C,are obtained with the help of Matlab.The apparent activation energies and pre-exponentials are calculated according to the Arrhenius equation.One catalyst coefficient and rate constants,apparent activation energies and pre-exponentials of fifty different reactions are obtained during the solving process.The activation energy values obtained are mostly in 30~125 kJ·mol-1.Then the reliability of kenitic models is checked.The results show that the calculation errors were almostly less than 10% and the the reliability of kenitic models is acceptable.