In China, developing a way to make coal into a slurry is a challenge due to a shortage of certain types of coal. By studying Shenhua coal, they found it's suitable for making coal water mixtures, but its low metamorphic nature makes it tough to form a slurry. Through grading technology, they came up with the right mix of coal quality, additives, and equipment to make the slurry work. They also found that using municipal sludge and black liquor to make a biological coal water mixture improved how it spread out. When tested in industrial boilers, they achieved high combustion efficiency and flexibility in load adjustments. By grinding the coal in a certain way, they boosted the mixture's concentration and increased productivity significantly.