Investigation On Electrostatic Fields Removed Of Solid Particles In FCC Slurry

Fluidized catalytic cracking?FCC?slurry contains a large number of aromatic hydrocarbon components which can be used as good raw material of value-added chemical products,such as needle coke,carbon black and carbon fiber.But FCC slurry contains some tiny solid particles,which seriously restricts the usage of FCC slurry.Therefore,FCC slurry must be purified before usage.Electrostatic method has an advantage in removing tiny solid particles,Multi-stage electrostatic separation technique can effectively improve the efficiency of electrostatic separation.But electrostatic method existed some problems such as,the stages of electrostatic were too much,the separation efficiency of single-stage was lower and lower with the increased electrostatic stages.In order to decrease the stages of electrostatic and increase the second stage efficiency of electrostatic separation,this research mainly study the pretreatment of FCC slurry before electrostatic separation.This study carried out sedimentation-electrostatic separation and modified the FCC slurry which experienced first stage of electrostatic separation to process the second stage electrostatic separation.By experiment research,FCC slurry experimented sedimentation-electrostatic separation,The addition of glycerol amount is 5%of FCC slurry quality,the addition of distilled water quantity account 50%of glycerol quality,the amount of flocculant account of 0.05%of FCC slurry,the mixing time is 25 min,the temperature is 80°C,the subsidence time is 180²00min.Under these experiment conditions,the separation efficiency reached 45%.Then the purification FCC slurry to process electrostatic separation.The conditions were determined through experiments:the best voltage was 11kv,the processing time was 30³5 min,the operating temperature was 110°C.Under the optimum operating conditions the best separation efficiency reached 41%.The separation efficiency of sedimentation-electrostatic on FCC slurry reached 86%.Sedimentation-electrostatic method was suitable for processing the FCC slurry which contains more resins and asphaltene.By modifying the FCC slurry after first stage electrostatic separation,improved the secondary electrostatic separation efficiency.The conditions can be determined through experiments:the best modifier was modifier A,the amount of modifier A accounted 0.5%of FCC slurry oil quality,mixing intensity was 600 r·min^-1,the best voltage was 10 kv,residence time was 25³0 min.Under the condition of the secondary electrostatic separation reached46%.Because through the first stage electrostatic separation,the eparation efficiency reached50%,after modifying secondary electrostatic,the separation efficiency arised 96%.Then explore the the mechanism of electrostatic with modifier A,the relative dielectric constant and particle size of solids increased in FCC slurry,which lesd to the solids were more easy to polarization and more easy to be removed.By modifying the FCC slurry after first stage electrostatic separation,was suitable for processing the solids whose relative dielectric constant and particle size were small in FCC slurry.