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 lm, 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 Á 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.

Slurryability and Influencing Mechanism of Hydrophobic Structures in Additive–Coal–Water Ternary System

“…The viscosity of CWS was determined by a rotary viscometer (NXS-4C, Chengdu Instrument Factory, China, ±5%) at shear rates of 10, 20, 40, 60, 80, and 100 s –1 . The relationship between the shear stress and shear rate of CWS was fitted using the three-parameter Herschel–Bulkley model (formula ), which can be used to judge the slurry flow model . By putting a certain volume of CWS ( V 2 ) into a test tube and recording the volume of supernatant ( V 1 ) after 7 days, the water bled rates can be obtained. where τ (Pa) is the shear stress; τ 0 (Pa) is yield stress; (s –1 ) is the shear rate; and K is the consistency coefficient.…”

Potential of Coal–Water Slurries as an Alternative Fuel Source during the Transition Period for the Decarbonization of Energy Production: A Review

“…For these reasons, many studies regarding the use of coal slurries as an alternative fuel have been carried out. Coal slurry fuels can be separated into different categories, depending on the type of liquid used to mix the solid coal particles, for example, CWS (coal-water slurry), COS (coal-oil slurry), COWS (coal-oil-water slurry), CMS (coal-methanol slurry), and CMWS (coal-methanol-water slurry) [11].…”

An experimental study on head loss characteristics of pipe bends for flow of coal–water slurry at high solid concentration

“…In previous years, several investigations 4–7 have been carried out to determine the rheological characteristics of multiparticulate slurry at different solid concentrations with and without additives. Zhu et al.…”

“…Moreover, pipelines can be laid in difficult geographic areas, reduce traffic, require little maintenance, and are reliable and operational throughout the year. 2,3 In previous years, several investigations [4][5][6][7] have been carried out to determine the rheological characteristics of multiparticulate slurry at different solid concentrations with and without additives. Zhu et al 4 investigated the effect of starch-based dispersants on the physical and chemical properties of a coal-water slurry.…”

“…However, the addition of styrene improves the static settlement of coal-water slurry. Li et al 5 performed an experimental study to improve the flow properties of low-rank coal water slurry by mixing it with medium-rank coals. The presence of weak acidic groups, high water adsorption capacity and high mineral density were significant parameters that affect the rheological characteristics of low-rank coal.…”