Patent ID: 6858090

Claim:
A closed loop cleaning process for removing hydrocarbon residue from a vessel in need of cleaning, comprising: first, treating a vessel in need of cleaning of hydrocarbon residue by liquefying at least a portion of the hydrocarbon residue with a terpene-based solvent, producing a mixture of spent solvent and hydrocarbon residue; second, removing the mixture of spent solvent and hydrocarbon residue from the vessel; third, rinsing the vessel with aqueous media, producing a spent aqueous media combined with a contaminant; fourth, removing the spent aqueous media and contaminant from the vessel; fifth, subsequent to said second step, returning to future service the spent solvent and hydrocarbon residue by the further steps of: sixth, separating the spent solvent of the mixture from the hydrocarbon residue by evaporating the spent solvent; seventh, condensing the evaporated solvent from said sixth step, producing a clean solvent suited for future service in treating a vessel in need of cleaning; and eighth, directing at least a portion of the hydrocarbon residue from said sixth step into a commercial product stream; ninth, subsequent to said fourth step, returning to future service the spent aqueous media by processing the spent-aqueous media with a means for cleaning the contaminant from the spent aqueous media, producing a clean aqueous media.