Process for the hydroconversion of coal

Claim 1

A process comprising: mixing in a first mixing zone a process solvent with a coal feed; introducing said coal feed and said process solvent into a liquefaction zone maintained at elevated temperature and pressure to effect at least a partial conversion of the coal into coal liquefaction products; introducing said coal liquefaction products into a fractionation zone to produce a coal liquefaction products residuum comprising substantially non-distillable soluble coal products and insoluble coal products; introducing the coal liquefaction products residuum into a second mixing zone; providing a deashing solvent, said deashing solvent consisting essentially of at least one substance having a critical temperature below 800 degrees F. selected from the group consisting of aromatic hydrocarbons having a single benzene nucleus and normal boiling points below about 310 degrees F., cycloparaffin hydrocarbons having normal boiling points below about 310 degrees F., open chain mono-olefin hydrocarbons having normal boiling points below about 310 degrees F., open chain saturated hydrocarbons having normal boiling points below about 310 degrees F., mono-, di, and tri-open chain amines containing from about 2-8 carbon atoms, carbocyclic amines having a monocyclic structure containing from about 6-9 carbon atoms, heterocyclic amines containing from about 5-9 carbon atoms, and phenols containing from about 6-9 carbon atoms and their homologs; introducing said deashing solvent into said second mixing zone; mixing said coal liquefaction products residuum with said deashing solvent to provide a prepared mixture; withdrawing said prepared mixture; introducing said prepared mixture into a first stage settler; maintaining said first stage settler at a temperature level in the range of from about 400 degrees F. to about 700 degrees F. and a pressure level of from about 600 psig to about 1000 psig to effect a separation of said prepared mixture in said first stage settler into a first heavy phase comprising insoluble coal products, some soluble coal products and some deashing solvent and a first light phase fraction comprising soluble coal products and deashing solvent; withdrawing said first heavy phase from the first stage settler; withdrawing said first light phase from said first stage settler; introducing said withdrawn first light phase into a second stage settler; maintaining said second stage settler at a temperature level in the range of from about 450 degrees F. to about 800 degrees F. and a pressure level in the range of from about 400 psig to about 1000 psig to effect a separation of said first light phase in said second stage settler into a second heavy phase comprising heavy soluble coal products and some deashing solvent and a second light phase comprising light soluble coal products and deashing solvent; withdrawing said second heavy phase from said second stage settler; withdrawing said second light phase from the second stage settler; introducing the withdrawn second light phase into at least a third stage settler; maintaining said third stage settler at an elevated temperature level and pressure level selected to provide a differential in the deashing solvent density existing within the second stage settler and the third stage settler sufficiently large to cause the second light phase to separate into a third heavy phase comprising light soluble coal products and some deashing solvent a third light phase comprising deashing solvent; withdrawing said third heavy phase from said third stage settler; withdrawing said third light phase from said third stage settler for recycle to second mixing zone to aid in providing said prepared mixture; introducing at least a portion of said third heavy phase into a hydrogen addition zone; treating said third heavy phase in said hydrogen addition zone to form a hydrogen-rich donor fraction; withdrawing said hydrogen-rich donor fraction from said hydrogen addition zone; and recirculating at least a portion of said withdrawn hydrogen-rich donor fraction to supplant at least a portion of said process solvent employed in preparing the coal liquefaction products.