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AssigneeInternational Coal Refining Company
InventorsEdwin N. Givens, David H. S. Ying
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There is described an improved liquefaction process by which coal is converted to a low ash and low sulfur carbonaceous material that can be used as a fuel in an environmentally acceptable manner without costly gas scrubbing equipment. In the process, coal is slurried with a solvent, passed through a preheater and at least two dissolvers in series in the presence of hydrogen-rich gases at elevated temperatures and pressures. Solids, including mineral ash and unconverted coal macerals are separated from the condensed dissolver effluent. In accordance with the improved process, fresh hydrogen is fed to each dissolver and the entrained gas from each dissolver is separated from the slurry phase and removed from the reactor system before the condensed phase is passed to the next dissolver in the series. In accordance with another process, the feeds to the dissolvers are such that the top of each downstream dissolver is used as a gas-liquid separator.
In a process for the solvent refining of coal wherein a slurry of finely ground coal in process solvent is passed through a preheater to a coal liquefaction stage in the presence of hydrogen-rich gases at elevated temperatures and pressures, the improvement comprising passing the slurry from the preheater in series through a plurality of dissolvers, feeding fresh hydrogen gas to each of said dissolvers, and separating entrained gases from the slurry phase exiting each dissolver and removing said gases from the liquefaction stage, the gas velocity being maintained at a rate to maintain backmix flow in the liquefaction stage so that solids do not settle out therein, and sufficient gas voids being maintained in and sufficient amounts of hydrogen gas being added to said dissolvers so as to insure good hydrogen transfer from the gaseous to the reacting condensed phase.
Dependencies are inferred from the claim text.