On the separation mechanism of high vibration frequency compound dry separator and multi-parameter optimization

Abstract

ABSTRACT Dry coal separation is the key technology for coal separation in arid and water-scarce areas. The content of −6 + 1 mm coal gradually increases, and the weak gravity affect of this part of coal restricts the separation effect, causing serious resource waste and environmental pollution. In this paper, a process intensification method for compound dry separation based on high-frequency vibration was proposed to improve the separation effect of fine coal. The kinematic characteristics of the bed surface with high-frequency vibration was captured by the three-channels acceleration sensor, and the motion trajectories of different regions on bed surface were reconstructed. The separation area was located at the front end of the vibrating bed, and the elliptical trajectory promoted the material to roll. However, the tail of the bed showed a linear trajectory, the main team to the transport of the material. And then the force characteristics of various density particles were studied by using spherical inertial sensors. Compared with low-density particle swarm, the collision between high-density particles was more obvious, causing serious loss of kinetic energy, which increased the motion difference of particles with different densities. Furthermore, the significance of the effects of vibration frequency, bed inclination and air velocity on the separation effect of −6 + 1 mm coal and the interaction between the factors were investigated. Furthermore, the influence of vibration frequency, inclination, and air velocity on the separation effect and the interaction among various factors were explored. The influence of frequency and inclination was more obvious than that of gas velocity. And then a mathematical model was established to predict the calorific value of clean coal. The results illustrated that at a vibration frequency of 37.52 Hz, a bed inclination angle of 13.69°, and an air velocity of 2.26 m/s, the calorific of product was increased from 4306 kcal/kg to 5868 kcal/kg, and the heat efficiency reached 90.18%. The results provide a referable way to realize the large-scale and high-efficiency dry separation of fine coal.