| 摘要 |
PURPOSE:To produce easily coal having a low to ultra-low ash content in high yields, by adsorbing crushed coal by gas under pressure, slurrying coal and reducing the pressure of the slurry to atmospheric pressure to allow coal particles having a low ash content to float. CONSTITUTION:Crushed coal and water from a tank 5 are mixed together in nearly equal quantities in a mixer 4 to slurry coal in water. The slurry is fed to a pressure-holding tank 7 by means of a pump 6 and a gas capable of being easibly adsorbed by coal (e.g. carbon dioxide gas 8) is blow through a nozzle 9 into the slurry under pressure to allow the carbon dioxide gas to be adsorbed by coal particles. The slurry of coal contg. carbon dioxide gas adsorbed is fed to a closed atmospheric fluidized bed separating tank 12 to reduce its pressure to atmospheric pressure, whereby the gas adsorbed inside coal oozes out on the surfaces of coal particles having a low ash content and as a result, bubbles are formed on the surfaces. Coal particles having a low ash content come up to the surface by the buoyancy of bubbles, and are fed through a drawn-out pipe 13 to a centrifugal dehydrator 14 to dehydrate them and to recover dehydrated coal 15 having a low ash content of 3% or below.
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