Coal desulfurization and deashing by high voltage pulse treatment in tap water

Abstract

Water is commonly used as the dielectric medium in High Voltage Pulse (HVP) disintegration. It is hypothesized that deionized water can achieve better efficiency than tap water and is prevailingly used in different laboratory-scale HVP applications. Since tap water is more easily accessible and inexpensive than deionized water, particularly in industrial applications, a study was carried out to investigate the viability of using tap water in lieu of deionized water for the HVP-enabled coal desulfurization and deashing application. Three coal samples were treated by HVP in tap water and deionized water to evaluate the HVP treatment efficiencies through paired-particle tests for density-fractionated particles and multi-particle tests for the as-received coal samples. Three repeat tests in tap water for each coal sample were performed for statistical analysis of the results. The paired-particle tests confirm that using both tap water and deionized water can acquire a similar HVP selectivity of breakdown in high-density particles. The multi-particle tests prove that the use of tap water would not negatively affect the effectiveness of the HVP treatment of the three coal samples. Three factors are considered to make the successful use of tap water in this study: 1) the HVP generator can generate pulses with a voltage rising time of ∼ 50 ns to promote the electrodynamic disintegration; 2) a Backpropagation Artificial Neural Network (BPANN) analysis algorithm was employed to ensure that the HVP parameters setup is optimized; 3) the coal samples contain pyrite to induce HVP selective breakdown in mineralized particles.