Patent ID: 8491721
Filing Date: 2013-07-23
Classification: B01D,B08B

Abstract:
1. A method of cleaning and degassing a storage vessel containing sludge comprising the steps of (a) mixing an oil release agent and the sludge to separate oil in the sludge from solids in the sludge, said separated oil floating on the surface of water in the vessel, (b) after a predetermined time period, removing from the vessel the oil floating on the surface of the water to leave within the vessel a mixture of water, solids, and hydrocarbons, (c) mixing a predetermined amount of an emulsifying agent and the mixture of water, solids, and hydrocarbons to substantially emulsify the hydrocarbons, so the level of volatile organic compounds remaining in the interior of the vessel is no greater than 5,000 ppmv, measured as methane, at least one hour after adding the emulsifying agent, and (d) measuring the level of volatile organic compounds in the vessel one or more hours after adding the emulsifying agent and opening the vessel to the atmosphere only when the level of volatile organic compounds remaining in the vessel is no greater than 5,000 ppmv, measured as methane, (e) removing from the vessel the mixture including the emulsified hydrocarbons.