Experimental Study On Variable-diameter Pulsed Jamming Bed For Refractory Coarse Coal Slime

A variable-diameter pulsed jamming bed separator was designed to overcome shortcomings of the separation performance of coarse coal slime in a traditional teeter bed separator. These shortcomings included poor separation accuracy, unreasonable distribution of the bed solids solvent concentration and low yield of clean coal.Firstly, effects of fluctuating and variable-diameter on experimental results were explored compared traditional teeter bed with variable-diameter pulsed jamming bed separator. Secondly, influences of cone angle, pulse on/off interval, pulse period, pulse amplitude and steady flow rate on the separation performance of coarse coal particles were investigated. Finally, an optimal operation condition having the best separation performance was determined by optimization analysis of response surface methodology based on the significance analysis of operating parameters.As observed in experimental results, the separation efficiency of variable-diameter pulsed jamming bed separator is better than that of the traditional teeter bed separator. The quantity efficiency of the designed separator reached the peak when pulse on/off interval is 1:1. Moreover, the possible error and the imperfect decreased as initially and increased afterwards, while the separation efficiency and quantity efficiency witnessed a reversed tendency with the increase of pulse period / pulse amplitude. In addition, stable water flow rate had an important influence on the partition factor of particles having a high density, and the possible error increased with the increasing stable water flow rate. Furthermore, based on the orthogonal analysis, the yield of clean coal, having an ash content of 10.00%, was 68.98% at the optimal operating conditions with pulse period of 1.74 s, pulsation amplitude of 69.98 L/h, and stable water flow rate of 373.20 L/h. Thus, it was concluded that the separation performance and the yield of clean coal were improved with introductions of a pulsating flow and variable-diameter structure to a traditional teeter bed separator.