Experimental and Numerical Simulation of Spent Catalyst Separation in an Active Pulsing Air Classifier

Research on recycling spent catalyst is at the forefront of preventing environmental pollution and recycling resources. An active pulsing air classifier is applied to recover the valuable concentrate from spent catalyst. A multi-factor separation experiment was designed using Box-Behnken module of Design-Expert software, the results show that the separation efficiency ranged from 96.26 to 99.29%. When the airflow velocity is 8.06 m/s, pulsing frequency is 3.55 Hz, feed frequency is 35 Hz, and thus 99.29% separation efficiency can be achieved. A sharp separation is achieved with a wider performance range of operation conditions. A DEM-CFD model is developed to study the gas-solid flow in a lab-scale active pulsing air classifier. In the model, the motion of particles is obtained using the Discrete Element Method facilitated with the concept of "particle-particle," while the gas flow by Computational Fluid Dynamics based on the local averaged Navier-Stokes equations. The simulated results agree reasonably well with the experimental observation. It will provide a cost-effective way to study the gas-solid flow in the larger-scale active pulsing air classifier with different geometrical, operational and material conditions.