Critical and supercritical cleaning of hydrocarbon-containing materials
A method for cleaning materials containing solids and/or liquids is disclosed which involves contacting the materials with an extracting fluid including Xe, NH 3 , lower aromatics, nitrous oxide, water, CO, CO 2 , H 2 O, lower alcohols, lower alkanes, lower alkenes, or mixtures or combinations thereof under conditions of temperature and pressure sufficient to maintain the fluid at, near or above its critical point and to products derived therefrom.
1. A process for cleaning a material comprising the step of:
charging a quantity of a material-to-be-treated selected from the group consisting of drilling fluids, reactor sludges, oil-contaminated soils, oil contaminated water, used oil, hydrocarbon fuels, tar sands, tanker bottoms, refinery bottoms, oil pit residues, refinery waste streams, refinery residue streams, paint wastes, and polymer wastes, where the material-to-be-treated comprises water and water soluble aqueous components, a non-aqueous fluid, and solid materials into an interior of an inner tube of a tubular extraction vessel comprising: an upper portion including an outer tube, an middle tube, and the inner tube; a semi-permeable membrane; and a lower portion,
charging a quantity of CO 2 to a plurality of interior sites of the tubular reactor until the fluid is at or above its critical point,
contacting the material-to-be-treated with the CO 2 under conditions of temperature and pressure sufficient to maintain the fluid at, near or above its critical point to produce a treated material comprising the CO 2 , the non-aqueous fluid and the solid materials;
concurrently, removing water and water soluble components via the semi-permeable membrane into the lower portion of the tubular extraction vessel to produce an aqueous product,
forwarding the treated material into a first separation vessel comprising an interior, a treated material inlet, a fluid outlet and a solids outlet having a venturi valve,
removing the solid materials from the first separation vessel through the venturi valve to a solids storage container to produce a solids product,
removing a fluid comprising the non-aqueous fluid and the CO 2 from the first separation vessel and forwarding the fluid to a second separation vessel having a fluid level sensor,
separating the fluid in the second separation vessel into used CO 2 and a non-aqueous fluid product, and
transferring the non-aqueous fluid product to a fluid storage container.
2. The process of claim 1 , wherein the material-to-be-treated is a drilling fluid and the non-aqueous fluid product comprises a hydrocarbon product substantially free of contaminants, and the solids product is substantially free of hydrocarbons and other contaminants.
3. The process of claim 1 , wherein the material-to-be-treated is a used oil and the non-aqueous fluid product comprises a cleaned oil substantially free of water and water soluble contaminants and substantially free of solids.
4. The process of claim 3 , wherein the cleaned oil has a lower sulfur content than the used oil prior to cleaning.
5. The process of claim 1 , wherein the material-to-be-treated is a hydrocarbon fuel and the non-aqueous fluid product comprises a cleaned fuel having a lower sulfur content than the hydrocarbon fuel prior to cleaning.
6. The process of claim 1 , wherein the material is a hydrocarbon contaminated soil and the non-aqueous fluid product comprises a hydrocarbon product substantially free of solids, water and water soluble contaminants, the solids product comprises a cleaned soil substantially free of hydrocarbon and other contaminants, and the aqueous product is substantially free of hydrocarbon.