Experimental study on the macerals enrichment of low-rank coal by rotary triboelectric separator

Abstract

The improvement of vitrinite content in low-rank coal can enhance liquefaction efficiency. In this work, an innovative rotary triboelectric separator (RTS) was used to enrich the macerals of low-rank coal. The effects of friction wheel speed (A), separation voltage (B), and feed rate (C) of RTS on the macerals enrichment were investigated, and the interactions of the three factors were explored via the response surface method. By the established model, all the three factors have significant effects on the vitrinite recovery R v, and the interaction between AC is stronger than AB and BC. Taking the maximum value of R v as the optimization target, the optimal prediction index was obtained and validated based on laboratory experiments. Under the optimum operating conditions, a maximum R v value of 74.48% was achieved at a friction wheel speed of 3220.14 rpm, a separation voltage of 30.18 kV, and a feed rate of 1.44 g/s. The average vitrinite content and R v of the verification experiments were 65.45% and 74.71%, respectively.