Study on the slurry properties of Xinjiang Zhundong coal water slurry controlled by particles size distribution

One of the most important technologies for the effective and clean use of coal is gasification. Currently, one of the most advanced gasification technologies being employed extensively is large-scale water-coal slurry entrained flow gasification. Rich coal resources may be found in Xinjiang’s Zhundong region. These resources are primarily low-rank coal, such as lignite and long flame coal, which have low ash content, high moisture content, and high volatile matter content. Based on the traditional pulping method, the slurry concentration of Zhundong coal is only 51%. Its large-scale applicability in coal water slurry fluidized bed gasification is limited by its poor slurry ability. A variety of technical means are combined to increase the slurry concentration of Zhundong coal, thereby improving the practicality and economy of Zhundong coal gasification. Initially, the study investigated the impact of various dispersant types on the apparent viscosity of water-coal slurry, and then established the optimal dosage of additives. The results indicated that pure naphthalene-based dispersants exhibited favorable compatibility with Zhundong coal, with the optimal concentration identified at 1.6%. Secondly, the surface structure, specific surface area and functional group distribution of Zhundong coal were studied by combining scanning electron microscopy, gas adsorption analyzer and infrared spectrometer. Research has indicated that Zhundong coal has a rough surface structure, a high specific surface area, and a specific quantity of hydrophilic functional groups. Because of these qualities, Zhundong coal has poor slurrying qualities. Additionally, it was discovered that adding fine particles will boost the viscosity of Zhundong coal slurry and enhance the fluidity of Zhundong coal water slurry when combined with rheological tests. Therefore, a crucial first step in maximizing the performance of water-coal slurry is determining how much tiny particles to add. Ultimately, the proper coal particle size and ratio were filtered out using the three-peak grading technique. The Zhundong coal slurry concentration climbed to 58%, the fluidity grade attained A, and the stability was good when the blending ratio of large, medium, and fine particles was 6∶1∶3.