Coal liquefaction process employing fuel from a combined gasifier

Claim 1

A combination coal liquefaction-gasification process comprising passing mineral-containing feed coal, hydrogen, recycle dissolved liquid solvent, recycle normally solid dissolved coal and recycle mineral residue to a coal liquefaction zone to dissolve hydrocarbonaceous material from mineral residue and to hydrocrack said hydrocarbonaceous material to produce a mixture comprising hydrocarbon gases, dissolved liquid and normally solid dissolved coal and suspended mineral residue; separating distillate liquid and hydrocarbon gases from a slurry comprising said normally solid dissolved coal, solvent and mineral residue recycling to said liquefaction zone a portion of said slurry; passing the remainder of said slurry to distillation means including a vacuum distillation tower for distillation, the slurry bottoms from said vacuum distillation tower comprising a gasifier feed slurry; said gasifier feed slurry comprising substantially the entire normally solid dissolved coal and mineral residue yield of said liquefaction zone substantially without normally liquid coal and hydrocarbon gases; passing said gasifier feed slurry to a gasification zone; said gasifier feed slurry comprising substantially the entire hydrocarbonaceous feed to said gasification zone; injecting water or steam into said gasification zone; said gasification zone including an oxidation zone having a maximum temperature in the range 2,200° to 3,600° F. for conversion of the hydrocarbonaceous material therein to synthesis gas; said synthesis gas having a mol ratio of H 2 to CO of less than 1; converting a portion of said synthesis gas in a shift reaction to a first hydrogen-rich stream and passing said first hydrogen-rich stream to said liquefaction zone for use as process hydrogen; the amount of hydrocarbonaceous material passed to said gasification zone being sufficient to enable said gasification zone to produce an additional amount of synthesis gas beyond the amount required to produce process hydrogen which increases the thermal efficiency of said process when burned as fuel in said process; separating H 2 from CO in at least a portion of said additional amount of synthesis gas to provide a second hydrogen-rich stream and a carbon monoxide-rich stream; and burning as fuel in said process an amount comprising at least 60 mol percent of the total CO plus H 2 content of said additional amount of synthesis gas to supply between 5 and 100 percent on a heat basis of the total energy requirement of said process; said carbon monoxide-rich stream providing at least a portion of said fuel burned.