Patent ID: 8470134

Claim:
A process for treating coal, comprising: heating coal in a chamber by (a) direct heat provided by an oxygen-deficient sweep gas flowed through the chamber and brought into contact with the coal, and (b) by indirect heat applied externally to the chamber, said heating of the coal being sufficient to cause volatile components of coal to be released into the sweep gas, the volatile components including condensable hydrocarbons, selecting a ratio of direct heat and indirect heat applied to the coal to increase the proportion of condensable hydrocarbons in the sweep gas to 15% or more; and treating the sweep gas to recover condensable hydrocarbons of the coal, wherein coal is continuously supplied into one supply end of a chamber and removed from another discharge end of the chamber, and the sweep gas is continuously supplied into the same supply end of the chamber and removed from the discharge end of the chamber in co-current flow; and wherein the log mean temperature differential between the sweep gas and the coal from the supply end to the discharge end is from about 300° F. to about 400° F.