Treating sludges and soil materials contaminated with hydrocarbons

A system for treating soil and other solids earth material contaminated with hydrocarbon fluids, said system comprising:

• dryer means including an inlet, a vapor outlet and a solids discharge outlet;
• oxidation means in communication with said solids outlet for receiving dried solids and for combusting hydrocarbons remaining on said dried solids to provide substantially hydrocarbon free solids;
• means for screening said solids to provide a feedstream having a particle size which averages about one inch or less;
• condenser means connected to said vapor outlet of said dryer means for receiving vapors from said dryer means;
• means for conveying at least a portion of said solids which have been discharged from said dryer means back to said inlet for mixing with the solids entering said dryer means to adjust the composition of said mixture entering said dryer means;
• and
• said system being operable to convey said solids to said dryer means for evaporation of liquid hydrocarbons and other liquids in said dryer means at a temperature of less than about 700.degree. F., convey vapors generated in said dryer means to said condenser means and to discharge substantially dried solids to said oxidation means and to discharge substantially hydrocarbon free solids from said oxidation means to means for receiving said solids.

A method for treating sludges containing liquid hydrocarbons and solids fines coated with said liquid hydrocarbons comprising the steps of:

• providing indirect rotary dryer means having an inlet, a vapor outlet and a solids discharge outlet;
• providing means in communication with the inlet of said dryer means for mixing said sludge with a quantity of solids selected from a group comprising diatomaceous earth and perlite to provide a thickened sludge to said dryer means;
• mixing said sludge with said solids to provide a thickened sludge and conveying said thickened sludge to said dryer means;
• heating said thickened sludge in said dryer means to a maximum temperature of about 700.degree. F. to vaporize hydrocarbon fluids and other fluids in said dryer means;
• condensing said vapors of said hydrocarbon fluids to provide recoverable liquid hydrocarbons;
• conducting dried solids from said dryer means and exposing said dried solids to oxidation means for oxidizing hydrocarbons coated on said dried solids;
• and
• disposing of said dried solids which are substantially hydrocarbon free.

A system for treating soil and other solids earth material contaminated with hydrocarbon fluids, said system comprising:

• dryer means including an inlet, a vapor outlet and a solids discharge outlet;
• oxidation means in communication with said solids outlet for receiving dried solids and for combusting hydrocarbons remaining on said dried solids to provide substantially hydrocarbon free solids;
• means for screening said solids to provide a feedstream having a particle size which averages about one inch or less;
• condenser means connected to said vapor outlet of said dryer means for receiving vapors from said dryer means;
• separator means in communication with said condenser means for receiving condensate from said condenser means including solids fines;
• and
• means for conveying a sludge of said solids fines to said inlet to be mixed with the mixture entering said dryer means;
• said system being operable to convey said solids to said dryer means for evaporation of liquid hydrocarbons and other liquids in said dryer means at a temperature of less than about 700.degree. F., convey vapors generated in said dryer means to said condenser means and to discharge substantially dried solids to said oxidation means and to discharge substantially hydrocarbon free solids from said oxidation means to means for receiving said solids.

A method for decontaminating soils and other solids earth-like materials to remove hydrocarbon substances therefrom comprising the steps of:

• providing rotary indirect dryer means including an inlet, a vapor outlet and a solids discharge outlet;
• reducing the particle size of said soil to an average of about one inch or less and introducing said reduced soil to said dryer means and heating said reduced soil to a maximum temperature of about 700.degree. F. to vaporize hydrocarbon fluids and other low boiling temperature fluids present in said soil;
• conducting vapors of said hydrocarbon fluids away from said dryer means and condensing said hydrocarbon fluids;
• and
• discharging dried and heated solids of said reduced soil from said dryer means and combusting said solids to oxidize hydrocarbons remaining coated on said solids to provide substantially hydrocarbon free solids for disposal.