Haishen Jiang

Study on Screening Efficiency of Banana Vibrating Screen Based on 3D DEM Simulation

The screening process of a banana vibrating screen was simulated based on 3D discrete element method, where Hertz-Mindlin (no-slip) Model was applied. The experiment design and data analysis were performed by Design-Expert software. The factors determining the screening efficiency and the interaction between those factors were identified. The results showed that the screening efficiency ranged from 72.6 to 92.8 %. The screening efficiency showed a Quadratic Relationship Model with gradient of sieve surface, vibrating direction angle, vibration intensity. When two of the factors were determined, the screening efficiency decreased gradually with the gradient of sieve surface and vibration intensity, but increased with the vibrating direction angle. The effects of various factors on the screening efficiency were in the following order: gradient of sieve surface, vibration intensity and vibrating direction angle. The effects of the interaction between those factors on the screening efficiency were in the following order: gradient of sieve surface × vibration intensity, vibrating direction angle × vibration intensity, and gradient of sieve surface × vibrating direction angle.

Research on separation mechanism of waste palladium catalyst in a structure-optimized compound dry separator based on DEM-CFD

Abstract Recovery of precious metals from waste catalysts is necessary. The compound dry separator provides a new method for the recycling of waste catalysts with special morphology. The bed surface structure was modified in consideration of the unique properties of spent palladium catalyst in petrochemical industry. The solid-fluid coupling method (DEM-CFD) was used to study the distribution of airflow on the bed surface and the motion characteristics of particle swarm with different combinations of properties. The results showed that the best size of the apertures of bed surface was 2 mm and the optimum installation angle (β) of the lattice bars on bed surface was 50°. The velocity of air flow was small in the backplane region, but relatively large in the region far away from the backplane. And so was the case with dynamic pressure. The dynamic pressure was the largest in the central wind apertures and decreased gradually along the upward direction. The key factor influencing the distribution and movement of the aggregate on the bed surface was the shape of particles, while the effect of density was relatively weak. The separation efficiency (Ef) in numerical simulation was 99.83%, which coincided with the actual experimental result (99.57%).