Cold Model Experimental Study On The Removal Of FCCS Catalyst Particles By Electrostatic Separation

Catalytic cracking slurry(FCCS) is a by-product of catalytic cracking process.It contains a large number of polycyclic aromatic hydrocarbons and is the main raw material for manufacturing high value-added products such as carbon black,carbon fiber and needle coke.However,the existence of catalyst particles limits its application.At present,the commonly used desorption methods are sedimentation method,filtration method,centrifugal method and electrostatic method.Among them,the electrostatic method has a high separation efficiency for solid particles less than 10 um.When the density of solid and liquid phase in slurry is close,and the solid concentration is low and the liquid resistivity is high,this method is especially applicable.In this paper,a set of electrostatic separation device is designed and built.The effects of structure parameters,physical parameters and operation parameters on the electrostatic separation efficiency are studied.The distribution of electric field intensity and the force on catalyst particles in the electrostatic separation device are simulated by COMSOL.Firstly,the effects of structure parameters,physical parameters and operation parameters on the electrostatic separation efficiency were studied experimentally.The results show that the electrostatic separation efficiency could be significantly improved by adding fillers between plates,but different fillers had different adsorption effects.For example,the adsorption efficiency of glass ball fillers was better than that of ceramic ball fillers,and the separation efficiency increased with the decrease of particle size of fillers.The electrostatic separation efficiency increased with the decrease of alkylbenzene viscosity and the increase of catalyst particle size.The separation efficiency could be improved with the increase of separation time and series,but the separation rate would decrease gradually.The separation efficiency increased first and then decreased with the increase of the applied electric field strength.In the frequency range from 0.9 k Hz to 4.0 k Hz,the separation efficiency decreased with the increase of AC power supply frequency.Then,according to the force analysis of catalyst particles in the electrostatic separation device,regression analysis of the experimental data was carried out,and a mathematical model for predicting the separation efficiency of the electrostatic separation device was established.The comparative analysis of experiments shows that the mathematical model has high prediction accuracy and can meet the needs of Engineering design.Finally,COMSOL was used to simulate the distribution of electric field intensity and the force on catalyst particles in the electrostatic separation device.The results show that the electric field intensity near the contact point of filler in the electrostatic separation device was larger and the applied voltage increased,which mainly affected the filler near the central electrode.The dielectrophoresis force and viscous resistance of catalyst particles were of the same order of magnitude in numerical value,and the electric field intensity near the contact point of filler in the electrostatic separation device increased.The two forces had the same trend.The research results in this paper have certain reference significance for the follow-up thermal model research and industrial application of electrostatic desorption technology of catalytic slurry.