METHOD FOR SAND CLEANING FROM OIL AND OIL PRODUCTS Russian patent published in 1995 - IPC

FIELD: oil producing industry and environmental control in cleaning sand of oil fields and coastal zone contaminated with oil in accidents of transportation and oil producing facilities. SUBSTANCE: method for sand cleaning from oil and oil products includes removal of sand layer and its treatment with aqueous solution with use of water from water basin, by sand washing, first, with water taken from water basin and heated up to 20-100 C with subsequent oil separation by settling; treatment of sand with counter-current of aqueous solution with addition of such amount of surfactant at which oil is separated from surface of sand solid particles with formation of water-oil emulsion; separation of sand from water-oil emulsion; water-oil emulsion breaking with the aid of deemulsifier to form separate layers of oil and water containing deemulsifier and surfactant separating these layers; separation of deemulsifier by distillation and its return to operation for breakage of water-oil emulsion formed in cleaning of next portion of sand; and aqueous solution with surfactant is directed for additional washing of sand; correction of amount of surfactant in solution and use for cleaning of new portion of sand, and also for rinsing sand to remove surfactant by means of water taken from water basin, which is directed for purification to compensate for its losses. EFFECT: higher efficiency of cleaning, provision of circulation and regeneration of cleaner, prevented pollution of environment and reduced consumption of cleaner.