| 摘要 |
A method and apparatus are provided for the dehydration of low rank coal, such as lignite, utilizing hot water. Particles of low rank coal are preheated, entrained in liquid, fed to a high pressure feeder, and transferred into a high pressure loop leading to a heat exchange vessel, and at a pressure of about 500-1,000 psi. Particles discharged from the bottom of the heat exchange vessel pass to the top of a dehydration vessel. Water at a temperature (e.g. 250 DEG -260 DEG C. at 700 psi) sufficient to facilitate dehydration of the coal is fed to the bottom of the heat exchange vessel, and to the particles as they pass from the heat exchange vessel to the dehydration vessel. For particles withdrawn from the bottom of the dehydration vessel the pressure is gradually reduced so that they do not explode, and then the liquid and particles are separated while still at a temperature of about 180 DEG -200 DEG F. utilizing a vibrating dewatering screen, Vortex sieve, and vibratory centrifuge. Liquid is withdrawn from a screen at a central portion of the dehydration vessel and fed to the bottom of the heat exchange vessel, and liquid is withdrawn from a central screen of the heat exchange vessel, passed to flash tanks, a Lamella gravity settler, and a disk filter, sodium, sulfur, and other minerals in the withdrawn liquid being removed from the system.
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