Study on Enhancing the Slurry Performance of Coal–Water Slurry Prepared with Low-Rank Coal

Abstract

Although coal–water slurry (CWS) with low-rank Shenhua coal has poor slurry performance, it is a good power coal with many advantages including low ash content and ease of incineration. This article establishes differences between the slurry performance of CWS prepared with low-rank Shenhua coal and medium-rank Shandong coal. Moreover, we examined the effects of coal powder gradation, water pre-adsorption, formulation of modified sodium lignosulfonate (SL-M) with other dispersants and stabilizer, and a combined preparation of coal samples on the apparent viscosity of CWS. Results showed that the existence of weak acid groups, strong water adsorption ability, and high-density mineral substances were the major factors that affected the slurry performance of low-rank Shenhua coal. Furthermore, when the average coal particle size was 26.19 µm, the apparent viscosity of CWS was lowest according to bimodal distribution. When low-rank coal was treated first with water pre-adsorption, the slurry performance of CWS was greatly improved and the apparent viscosity was only 1200 mPa · s when the solid concentration was 63%, showing an increase of 3%. Finally, when low-rank Shenhua coal was combined with medium-rank Shandong coal, apparent viscosity was enhanced.