Prediction of Coal Slurry Pipeline Transportation Grading Reduction and Its Influence on Pipe Transportation Parameters

Abstract

Coal slurry pipe, being a new type of energy transportation mode, changes of the particle composition and the effect on other parameters are worth studying. Comparison of ring tube test measured data and batch grinding model simulation data shows that batch grinding model can predict the coal particle gradation to a certain extent. The effect of collision and wear of overcurrent components in the centrifugal pump, friction and collision between particles and piping and piping accessories, and initial particle size distribution during hydraulic conveying were also investigated by laboratory studies. Meanwhile, the effect of particle composition change on slurry viscosity, hydraulic resistance and minimum resistance critical velocity was studied based on the experimental data. The experimental and theoretical analysis indicates that the change of slurry particle composition can lead to the change of viscosity, resistance and minimum resistance critical velocity of the slurry. Moreover, based on the previous studies, the calculation model of minimum resistance critical velocity of coal slurry is proposed.

Study on the effect of grade change on rheological parameters of pipeline hydraulic coal transportation

“…The particle refinement process in the pipeline transport of coarse-grained coal slurry is complex, involving slurry pumping, particle-pipe friction and collision, interparticle collision, and particle interaction with various gauges, pipe valves, and bends, and therefore no theory or model has yet been developed to describe coarse coal particle refinement. The results of the authors' previous research also indicate that the analogy method can be used to analogize the coarse particle coal slurry pipeline hydrodynamic conveying process to a special ball mill grinding process, based on the grinding theory, to study the pipeline coal particle refinement [5] . Most of the research of domestic and foreign scholars on this theory focuses on the grinding mechanism of iron ore concentrate and lead-zinc ore and the method of determining relevant parameters [17][18][19][20] .…”

“…The results of the authors' previous research also indicate that the analogy method can be used to analogize the coarse particle coal slurry pipeline hydrodynamic conveying process to a special ball mill grinding process, based on the grinding theory, to study the pipeline coal particle refinement [5] . Most of the research of domestic and foreign scholars on this theory focuses on the grinding mechanism of iron ore concentrate and lead-zinc ore and the method of determining relevant parameters [17][18][19][20] .…”

“…3, the viscosity tends to increase with the extension of time, but the increase gradually slows down. Previous studies have shown that the coal slurry viscosity is mainly related to the volume concentration of fine particles and the limiting concentration [17] .…”

“…Coal slurry pipeline conveying is a new type of coal transportation method, in which coal lumps are crushed into coarse particles with a particle size of less than 1.5 mm, mixed with water to form a solid-liquid two-phase flow of coarse particles, and transported over long distances through pipelines, which has many advantages, such as energy saving, economy, practicality, and environmental protection [1][2][3] . However, since coal with less hardness is easily broken and refined during hydraulic transportation [4][5][6][7][8] , some factors such as the effect of pumps on particles, wear at the bottom of the pipeline, the effect of instruments and pipe valves on particles, and inter-particle collisions may lead to this phenomenon [9][10][11][12] . After refinement, changes in the specific gravity of different particle sizes can lead to changes in viscosity, which in turn affects the conveying efficiency.…”

“…The phenomenon of particle industrial refinement has been observed in experiments many times, Chen Zuobing [13] explored the effect of different particle size grades of slag on the grinding efficiency and used a vertical roller mill for industrial slag processing, and the experimental data showed that for the optimized particle size gradation, the grinding rate was increased significantly; Li Guofeng [14] investigated the effect of the milling process parameters on the particle size characteristics of the product, and used a laser particle size meter to measure the particle size distribution of the milled The particle size distribution of the product after grinding was measured using a laser particle size meter, and the R-R particle size characteristic equation was also used for particle size analysis, which suggested that the grinding rate was relatively uniform when the media ratio was 2:3 and the material ball ratio was 0.6. However, the grading refinement laws are poorly studied, despite individual prior foundations [5,17] . Chen [15] found that very fine particle size (<53 μm) leads to a significant increase in the dynamic viscosity of the slurry.…”