Study On The Influence Of FCC Slurry Composition And Solid Particles On Carbonization

FCC slurry has the advantages of high content of short side chain aromatics,proper amount of aliphatic alkanes,a small amount of asphaltene and low ash,etc.It is a good feedstock for producing needle coke after pretreatment.Generally,the quality of coke is related to carbonization conditions,the chemical composition of feedstock,ash and solid particle content.However,the chemical composition of the FCC slurry is extremely complex,and the chemical composition of each narrow fraction also varies greatly.Besides,the content of solid particles in the feedstock also have a great influence on the quality of the coke.Therefore,it is of great significance to deeply study the relationship between the composition of the FCC oil fraction,the solid particles and the coking properties to improve the utilization of FCC slurry.In this paper,five narrow fractions of Liaohe FCC slurry have been systematically studied,including A(350-400?),B(400-440?),C(440-470?),D(470-500?)and E(<500?).Firstly,the basic properties of narrow fractions of FCC slurry were analyzed.Besides,the relative content of aromatics in the feedstock,the hydrogen-donating ability of each fraction and its thermal stability were analyzed by UV spectroscopy,1H-NMR and so on.Secondly,Microscopy and X-ray diffractometer were used to determine the optical texture of the coke and its crystal lattice parameters.And the effect of the composition of the feedstock and the type and the content of solid particles on the coke formation were investigated.The research shows that the coke produced by the feedstock A is mainly mosaic structure(about 55%),while the feedstock C is mainly watershed-type structure(about 85%),and OTI value of coke produced by four feedstock: C>B>D>A.Compared to the tricyclic and tetracyclic aromatics,the five rings aromatics in the feedstock are not conducive to the formation of a streamlined structure of coke.Through the comparison of Co-carbonization,it is found that the feedstock BC has a good synergistic effect and the resulting coke has the best micro-morphology.In addition,the composition of the raw material A differs from the composition of the raw material BC.Compared to the intermediate products produced from the two raw materials,the generated coke differs greatly.The anisotropic structure of coke is related to the content of solid particles in the feedstock.When the coke powder content is less than 80 ?g/g,the effect on the morphology of coke formation is small.When the coke powder content is more than 150 ?g/g,the mosaic structure in coke gradually increases as the coke powder content increases.When the catalyst powder content is less than 50 ?g/g,the effect on the morphology of coke formation is small.When the catalyst powder content is greater than 80 ?g/g,the watershed-type structure in the coke gradually decreases as the coke powder content increases,and the mosaic structure decreases.gradually increase.The catalyst powder has a more significant effect on the coke morphology than the coke powder.