Process for the discharge of ash concentrate from a coal deashing system

Claim 1

In a process for separating a feed mixture comprising soluble coal products, insoluble coal products and a solvent in a separation zone, said 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, in which said feed mixtures is maintained in said separation zone at an elevated temperature and pressure to separate said feed mixture into a light fraction and into a heavy fraction comprising insoluble coal products and some solvents including some soluble coal products present therein and in which withdrawing said heavy fraction from said separation zone and reducing the pressure level of said heavy fraction at least about 100 psig. results in a deposition of said soluble coal products dissolved in said solvent in said heavy fraction upon the interior surface of a withdrawal conduit through which said heavy phase is passed, the improvement which comprises: introducing a separate stream of carrier fluid, inert with respect to materials present in said heavy fraction under conditions within the withdrawal conduit, into said withdrawal conduit under such conditions that a turbulent flow profile is formed by at least said stream of said carrier fluid within said withdrawal conduit to prevent or substantially minimize the deposition of or effect removal of any accumulated soluble coal products by contact with said carrier fluid.