Research on the application of fractal gradation high concentration pulping new technology

CHANG Fujun; SUN Haiyong; LI Lei; LIU Jinqiu

doi:10.3969/j.issn.1007-7677.2025.02.006

Abstract：China's coal chemical enterprises have a huge market demand for the preparation of high-quality coal wa-ter slurry from bituminous coal,sub bituminous coal and lignite at present,however the current coal water slurry prepa-ration technology in China still has limitations such as not completely changing the particle size distribution state of rod mill slurry preparation,not being able to adapt to high grindability index coal types,still having room for improvement in coal slurry concentration and high slurry energy consumption.It is urgent to study new technologies for high concen-tration slurry preparation with fractal gradation.Aiming at the problems of high investment and energy consumption in the existing slurry preparation process,under the guidance of the slurry preparation concepts of"replacing grinding with crushing""premixing to form slurry"and"particle shaping",taking Shenfu Dongsheng coal as the raw material,the influence law of particle morphology on the performance of coal water slurry was studied.A new high-concentration slurry preparation technology with fractal gradation was developed,and an industrial test with a raw coal treatment scale of 100 tons per hour was completed.The advantages of the new technology were analyzed through the comparison of the unit load,the performance of coal water slurry products,the civil engineering investment and the energy con-sumption of slurry preparation.The results show that the performance of coal water slurry is directly related to the mor-phology of coal powder particles.The higher the roundness and the smaller the aspect ratio of the prepared materials,the better the particle morphology,and thus the better the performance of the prepared coal water slurry.In the newly developed high-concentration slurry preparation technology with fractal gradation,the raw coal with a particle size lar-ger than 50 mm is crushed to less than 1 mm at one time by an ultra-fine crusher.The coal powder with qualified parti-cle size is then premixed and shaped to prepare the finished coal water slurry.The particle size,fluidity and stability of the coal water slurry meet the requirements for the use of the gasifier.The fractal gradation process broadens the range of selectable coal types,increases the concentration of the coal water slurry,reduces the installed power of the main e-quipment,cuts down the civil engineering investment,and lowers the power consumption for slurry preparation.