Catalytic Cracking Performance And Kinetics Of Heavy Petroleum Fractions From Huizhou Refinery

On one hand,the crude oil is heavier and inferior,on the other hand,the demand on clean light oil and high quality of raw materials are increasing continuously.At the same time,requirements on environmental protect are stringent.All these reasons put forward higher request on oil refinery industry.Huizhou refinery of CNOOC cooperated with China University of Petroleum(Beijing).On account of the typical feed that Huizhou refinery processed,heavy oil processing scheme were developed to enhance the light oil yield.For the target,this research studied the catalytic cracking performance of vacuum gas oil(VGO)and light deasphalted oil(LDAO)of two typical crudes(Penglai and Daliya crudes)processed in Huizhou refinery.In the end,the corresponding 7-lump kinetic model was established.The catalytic cracking performance of Penglai VGO,Penglai VGO+LDAO(the mass ratio of VGO:LDAO was 3:2),Daliya VGO and Daliya VGO+LDAO(the quality ratio of VGO:LDAO was 3:2)were studied as equilibrium catalyst provided by Huizhou refinery and a small-scale confined fluided bed experimental apparatus were used.The effects of reaction temperature,catalyst to oil weight ratio,weight hourly space velocity(WHSV),steam to oil weight ratio on product yields and distribution were investigated.As a result,the optimized operating conditions were determined,reaction temperature 490 ℃,catalyst to oil weight ratio 5,WHSV 25 h-1 and steam to oil weight ratio 0.10.Under this conditions,higher light oil yield and lower dry gas and coke yields can be obtained.On the whole,the rank of the catalytic cracking performance of those four material from high to low was that Daliya VGO>Penglai VGO>Penglai VGO+LDAO≈Daliya VGO+LDAO.In this thesis,a seven-lump kinetic model of catalytic cracking was established further.Firstly,the feed was divided into three lumps,alkyl carbon,naphthenic carbon and aromatic carbon according to its structural group composition.What’s more,the products were divided into four lumps,diesel,gasoline,liquefied petroleum gas(LPG)and dry gas+coke.Then the corresponding reaction networks were given and kinetic expressions were deduced.Based on the experimental data,a Matlab program was compiled to seek the parameters of the 7-lump kinetic models at 753.15 K and 773.15 K.In the end,the reliability of the model was tested.The results showed that most of the relative errors between calculated value and experimental value were within 10%,and the average relative errors of three target products,gasoline,diesel and LPG were within 7%,which indicated that the model could be reliable.