Research On Coarse Coal Slime Separation Mechanism And Regulation Of Inflatable Tapered Diameter Separation Bed

Based on significant density differences of particles in coarse coal slime, a novel inflatable tapered diameter separation bed system, including an inflatable tapered diameter separator with structured design and corollary equipment was established to recover combustible components from coarse coal slime. Prior to separation practice, feed samples were analyzed by Scanning Electron Microscope(SEM) to obtain microscope pattern images. The analysis of SEM images was carried out by employing JMicro Vision software to investigate grey scale variations in different areas in images, demonstrating coarse coal slime sample superficial material composition variations directly.Particle and particle swarm relaxation phenomena have been investigated: Initially, single particle forces in relaxation process have been analyzed comprehensively. By comparing different forces acting on single particle, major forces with significant impact on particle movements have been highlighted, while forces with negligible effect have been overlooked. Afterwards, in respect of particle swarm relaxation, an assumption which assumes particle swarm drag coefficient is merely subject to Reynolds number of flow nearby single particle in particle swarm has been proposed. Meanwhile, partial minimum energy principle assumption has been demonstrated to interpret particle swarm agglomeration in particle fluid system.Particle movements and fluid field evolution have been studied with Computational Fluid Dynamic method coupling with Discrete Element Method. Different particles’ velocities and trajectories evolution have been extracted and analyzed from the simulation. In the water flow field, segregation and separation between particles with different densities have been successfully simulated. However, particle agglomeration on the wall has negative effect on the whole separation process.This thesis explores upstream water flow to force sedimentary particles back into separation area by designing upstream water holes on the wall. The upstream water flow effect has been investigated using FLUENT software. Results show that upstream flow is capable of adjusting flow field distribution nearby the wall, which verifies the feasibility and effectiveness of upstream design.Experimental analysis of separating-3+0.5mm coarse coal slime by inflatable tapered diameter separation system has been carried out. After considering parameter effects of obliquity, water flow and feed concentration on combustible recovery respectively, three factors and three levels orthogonal experiment has been projected by Design Expert software and conducted. The results reveal the optimized levels of each factor and level combination. Thereafter, Scanning Electron Microscope(SEM) and Xray fluorescence spectroscopy technique have been employed to assess separated materials. The results show that it is an efficient way to deprive coarse coal slime of gangue component by implementing inflatable tapered diameter separation system.According to overflow variation in inflatable tapered diameter separation system, it is necessary to explore advanced system control system to adjust overflow automatically. For the non-linear separation system, a double input and single output Adaptive Fuzzy Neural Network(ANFIS) control system has been established. By simulating the control system with MATLAB/Simulink, the adaptive fuzzy neural network control system has been optimized, as well as control parameters. Simulation results show that overflow control in the inflatable tapered diameter separation system becomes smoother and more rapid with the ANFIS controller. Compared to conventional fuzzy control method, the overshoot in valve position, the adjustment time have all improved.