Method for suppressing asphaltene formation during coal liquefaction and separation of solids from the liquid product

Claim 1

A method for suppressing asphaltene formation during coal liquefaction which comprises the steps of: (a) contacting the coal at a temperature of from about 150° C. to about 450° C. and a pressure of from about 10 to about 300 atmospheres with hydrogen and a hydrogenated coal oil solvent having been hydrogenated to remove at least about 80% of the asphaltenes and containing a small amount, up to 3 wt. %, of benzene soluble asphaltenes; (b) separating gas from the resultant mixture to provide a liquid phase comprising coal extract, liquefaction zone effluent solvent and finely divided particles; (c) commingling said liquid phase with from about 10 wt. % to about 1000 wt. % of a light aromatic solvent selected from the group consisting of benzene, toluene and xylene at a temperature of from about 10° C. to about 150° C. and a pressure of from about atmospheric to about 25 atmospheres; (d) separating solids and light aromatic solvent from the resultant liquid mixture; (e) hydrogenating at least a portion of the remaining liquid mixture to remove at least about 80 percent of the asphaltenes; and (f) supplying resultant hydrogenated liquid to step (a) as said coal oil solvent.

Claim 2

A method for suppressing asphaltene formation during coal liquefaction which comprises the steps of: (a) contacting the coal at a temperature of from about 150° C. to about 450° C. and a pressure of from about 10 to about 300 atmospheres with hydrogen and a hydrogenated coal oil solvent having been hydrogenated to remove at least about 80% of the asphaltenes and containing a small amount, up to 3 wt. %, of benzene soluble asphaltenes; (b) separating gas from the resultant mixture to provide a liquid phase comprising coal extract, liquefaction zone effluent solvent and finely divided particles; (c) commingling said liquid phase with from about 10 wt. % to about 1000 wt. % of a light aromatic solvent selected from the group consisting of benzene, toluene and xylene at a temperature of from about 10° C. to about 150° C. and a pressure of from about atmospheric to about 25 atmospheres; (d) separating solids and light aromatic solvent from the resultant liquid mixture; (e) hydrogenating at least a portion of the remaining liquid mixture to remove at least about 80 percent of the asphaltenes; and (f) supplying resultant hydrogenated liquid to step (a) as said coal oil solvent.