PROCESS FOR PYROLYZING COAL USING A RECYCLED HYDROGEN DONOR

摘要

A process for pyrolyzing coal using a recycled hydrogen donor includes introducing a coal feed to a pyrolysis zone and heating the coal feed to a temperature of about 300° C. in the absence of hydrogen. A hydrogen donor solvent is introduced to the pyrolysis zone after the coal feed is heated to about 300° C., and the temperature of the coal feed and the hydrogen donor solvent is increased to about 475° C., while increasing a pressure in the pyrolysis zone to at or above a vapor pressure of the hydrogen donor solvent. At least an aromatic hydrocarbon rich fraction is separated from the coal tar stream and hydrogenated. The hydrogenated aromatic hydrocarbon rich fraction is recycled to the pyrolysis zone as the hydrogen donor solvent.

主权项

1. A process for pyrolyzing coal using a recycled hydrogen donor, comprising:
introducing a coal feed to a pyrolysis zone; heating the coal feed to a temperature of about 300° C. in the absence of hydrogen; introducing a hydrogen donor solvent to the pyrolysis zone after the coal feed is heated to the temperature of about 300° C.; increasing the temperature of the coal feed and the hydrogen donor solvent, while increasing a pressure in the pyrolysis zone to at or above a vapor pressure of the hydrogen donor solvent to evolve coal tar from the pyrolysis zone; increasing the temperature of the coal feed and the hydrogen donor solvent while maintaining the pressure in the pyrolysis zone at or above the vapor pressure of the hydrogen donor solvent to produce a coke stream and a coal tar stream until no further coal tar is evolved from the pyrolysis zone; reducing the pressure in the pyrolysis zone to approximately atmospheric pressure while increasing the temperature of the coal feed and the hydrogen donor solvent to about 1,000° C. to about 2,000° C.; separating at least an aromatic hydrocarbon rich fraction from the coal tar stream; hydrogenating the aromatic hydrocarbon rich fraction; and, recycling the hydrogenated aromatic hydrocarbon rich fraction to the pyrolysis zone as the hydrogen donor solvent.