Water wash/oil wash cyclonic column tank separation system

Abstract

The invention is directed to a method and apparatus for removing oil base drilling mud or like contaminants from drill cuttings. A continuous phase liquid, such as, base oil or wash water, is used to wash the contaminants from the cuttings. The continuous phase liquid and the contaminants removed from the cuttings are separated for recirculation and reuse. The separation system (10) of the invention includes a wash drum (14) for agitating the contaminated cuttings and continuous phase liquid together, a drying screen (16) for separating the larger solids from the liquid phase, a first column tank (18) and a pair of centrifuges (24 and 26) for separating the smaller solids from the liquid phase, and second and third column tanks (20 and 22) for separating the continuous phase liquid from the removed contaminants. When the continuous phase liquid is aqueous, for example, salt water mixed with the detergent, the apparatus of the invention includes a de-oiling, liquid/liquid hydrocyclone (30) to facilitate the separation of the continuous phase liquid and the removed contaminants. To further reduce oil contaminants on the drill cuttings to 0-1% dry weight prior to cuttings disposal, the system includes a low temperature thermal processor (500) which receives stabilized solids from the drying screen (16) and the centrifuges (24 and 26). The low temperature thermal processor (500) includes a heated hopper (502), crusher rollers (504), and agitator dryer (506), a condenser (508), and a condensate column tank (510).