A physical coal cleaning approach for clean energy production from low grade Lakhra coal of Pakistan using diester table

Abstract

In this work coal from Lakhra (coal mine in Pakistan) was subjected to a physical technique for mineral matter and sulfur reduction by using diester table. Effect of particle size and coal-to-water ratio of slurry were studied. A reduction of 85% in sulfur content and 88% in ash content for 500 µm coal sample was observed. While at 300 µm size sulfur and ash content were reduced about 77% and 80% respectively. At 150 µm size, the reduction in sulfur and ash was observed to be lesser (54% and 55% respectively) due to the decrease in specific gravity difference of coal
and impurity (i.e. sulfur and ash). GCV increased from 17.2 MJ/kg of the raw coal to 23.3 MJ/kg of cleaner fraction obtained at 500 µm. Based on the results of this study, diester table can be proposed to be a simpler however an effective physical coal cleaning method to reduce sulfur and ash content. Besides other parameters, particle size is a crucial parameter to impact the cleaning efficiency and because of the greater difference in specific gravity of coal and impurity, higher particles size used in this study resulted in the cleanest product.