Method of removing dissolved oil from produced water

Claim 1

A method of removing dissolved oil from water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: turbulently contacting a first gas with the water to create bubbles that move dissolved oil particles to a surface of the water, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromonofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions; and removing the dissolved oil from the surface of the water.

Claim 2

A method of removing dissolved oil from water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: turbulently contacting a first gas with the water to create bubbles that move dissolved oil particles to a surface of the water, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromonofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions; and removing the dissolved oil from the surface of the water.

Claim 23

A method of removing dissolved oil from water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: turbulently contacting a first gas and a second gas with the water to create bubbles that move dissolved oil particles to a surface of the water, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the second gas being sufficiently buoyant to promote movement of bubbles of the first gas to a surface of the water from which dissolved oil is removed; the turbulent contacting occurring in a mixing tee to create bubbles that move dissolved oil particles to the surface of the water, the mixing tee comprising a chamber having a water inlet for the water, a gas inlet for the first and second gases, and an outlet through which the water and gas mixture is discharged, the gases being introduced through a conduit having a smaller diameter than the diameter of the water inlet, the conduit terminating adjacent the water inlet and propelling the gases against the inward flow of the water to create a counterflow of water and gas that enhances formation of bubbles in the chamber, an annular constriction being provided around the exterior of the conduit between the conduit's termination adjacent the water inlet and the remainder of the chamber; introducing the contacted water and gases tangentially into a flotation tank having an upper region and a lower region to create a circular flow therein; introducing the first and second gases into the flotation tank at the lower region which is below the level at which the water is tangentially introduced into the flotation tank; and providing the flotation tank with an upper baffle and a lower baffle, both of which are substantially horizontally disposed in the interior of the tank between a level at which the water is tangentially introduced into the flotation tank and the lower region, the upper baffle having a central opening through which water flows downwardly and the second baffle being a substantially circular plate surrounded by a substantially annular opening through which water flows downwardly in the flotation tank, the lower baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, and the upper baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, the upper baffle being provided with an upper vent for venting bubbles from beneath the upper baffle to a position adjacent the surface of the water in the water in the flotation tank, the lower baffle being provided with a lower vent for venting bubbles from beneath the lower baffle to a position adjacent the underside of the upper baffle; and removing dissolved oil from said surface.

Claim 24

A method of removing dissolved oil from water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: turbulently contacting a first gas and a second gas with the water to create bubbles that move dissolved oil particles to a surface of the water, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the second gas being sufficiently buoyant to promote movement of bubbles of the first gas to a surface of the water from which dissolved oil is removed; the turbulent contacting occurring in a mixing tee to create bubbles that move dissolved oil particles to the surface of the water, the mixing tee comprising a chamber having a water inlet for the water, a gas inlet for the first and second gases, and an outlet through which the water and gas mixture is discharged, the gases being introduced through a conduit having a smaller diameter than the diameter of the water inlet, the conduit terminating adjacent the water inlet and propelling the gases against the inward flow of the water to create a counterflow of water and gas that enhances formation of bubbles in the chamber, an annular constriction being provided around the exterior of the conduit between the conduit's termination adjacent the water inlet and the remainder of the chamber; introducing the contacted water and gases tangentially into a flotation tank having an upper region and a lower region to create a circular flow therein; introducing the first and second gases into the flotation tank at the lower region which is below the level at which the water is tangentially introduced into the flotation tank; and providing the flotation tank with an upper baffle and a lower baffle, both of which are substantially horizontally disposed in the interior of the tank between a level at which the water is tangentially introduced into the flotation tank and the lower region, the upper baffle having a central opening through which water flows downwardly and the second baffle being a substantially circular plate surrounded by a substantially annular opening through which water flows downwardly in the flotation tank, the lower baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, and the upper baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, the upper baffle being provided with an upper vent for venting bubbles from beneath the upper baffle to a position adjacent the surface of the water in the water in the flotation tank, the lower baffle being provided with a lower vent for venting bubbles from beneath the lower baffle to a position adjacent the underside of the upper baffle; and removing dissolved oil from said surface.

Claim 26

A method of removing dissolved oil from particulate matter contained in water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: introducing water containing particulate matter into a sump tank where the particulate matter accumulates on the bottom; introducing a gas into the sump tank and contacting it with the particulate matter, the gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromofluoromethane and nitrous oxide, the gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the gas promoting movement of the oil particles to a surface of the water in the sump tank; and skimming oil from the surface of the water.

Claim 27

A method of removing dissolved oil from particulate matter contained in water, the dissolved oil being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: introducing water containing particulate matter into a sump tank where the particulate matter accumulates on the bottom; introducing a gas into the sump tank and contacting it with the particulate matter, the gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafluoromethane, dichloromofluoromethane and nitrous oxide, the gas comprising an effective amount of the compound to molecularly attract the dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the gas promoting movement of the oil particles to a surface of the water in the sump tank; and skimming oil from the surface of the water.

Claim 29

A method of removing dissolved oil from water and sand contained in produced water having dissolved oil particles contained therein, the dissolved oil particles being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: mixing a first and second gas, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafloromethane, dichloromofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the second gas being selected from the group consisting of natural gas, air and nitrogen; p1 contacting in a mixing tee the first and second gases with water to create bubbles that move dissolved oil particles to a surface of the water, the mixing tee comprising a chamber having a water inlet for the water, a gas inlet for the first and second gases, and an outlet through which the water and gas mixture is discharged, the gases being introduced through a conduit having a smaller diameter than the diameter of the water inlet, the conduit terminating adjacent the water inlet and propelling the gases against the inward flow of the water to create a counterflow of water and gas that enhances formation of bubbles in the chamber, an annular constriction being provided around the exterior of the conduit between the conduit's termination adjacent the water inlet and the remainder of the chamber; introducing the contacted water and gases tangentially into a flotation tank to create a circular flow therein; introducing the first and second gases into the flotation tank at a lower level which is below the level at which the water is tangentially introduced into the flotation tank; providing the flotation tank with an upper baffle and a lower baffle, both of which are substantially horizontally disposed in the interior of the tank between a level at which the water is tangentially introduced into the flotation tank and the lower level, the upper baffle having a central opening through which water flows downwardly and the second baffle being a substantially circular plate surrounded by a substantially annular opening through which water flows downwardly in the flotation tank, the lower baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, and the upper baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, the upper baffle being provided with an upper vent for venting bubbles from beneath the upper baffle to a position adjacent the surface of the water in the flotation tank, the lower baffle being provided with a lower vent for venting bubbles from beneath the lower baffle to a position adjacent the underside of the upper baffle; introducing a portion of the contacted water, which is substantially free of sand, from the flotation tank, into a vacuum vessel to cause a liberation of a portion of the first and second gases dissolved in the water, and to produce a water fraction in the vacuum vessel; removing the water fraction from the vacuum vessel; compressing the gases liberated in the vacuum vessel so that increased pressure condenses water out of the liberated gases; contacting the gases liberated in the vacuum vessel with a desiccant to remove water; reducing the temperature of the gases liberated in the vacuum vessel after they leave the desiccant until one of the gases liquifies, then separating the liquified gas from remaining gas; removing sand from the water in the flotation tank by introducing a portion of the contacted water, containing sand, from the flotation tank into a sump tank where the sand accumulates on the bottom; introducing the first and second gases into the sump tank and contacting the sand with the gases; and skimming oil from the surface of the water in the sump tank, wherein dissolved oil is removed from said surface, and said contacted water separates into a portion which is substantially free of sand, and a portion containing sand.

Claim 30

A method of removing dissolved oil from water and sand contained in produced water having dissolved oil particles contained therein, the dissolved oil particles being solvated by water molecules, the dissolved oil comprising a compound which comprises hydrogen, carbon and at least one element from the group consisting of oxygen and nitrogen, the method comprising the steps of: mixing a first and second gas, the first gas comprising a compound which has a dipole moment and is selected from the group consisting of dichlorodifluoromethane, methyl fluoride, tetrafloromethane, dichloromofluoromethane and nitrous oxide, the first gas comprising an effective amount of the compound to molecularly attract dissolved oil particles, and preferentially displace solvating water molecules, through hydrogen bonding and dipole interactions, the second gas being selected from the group consisting of natural gas, air and nitrogen; p1 contacting in a mixing tee the first and second gases with water to create bubbles that move dissolved oil particles to a surface of the water, the mixing tee comprising a chamber having a water inlet for the water, a gas inlet for the first and second gases, and an outlet through which the water and gas mixture is discharged, the gases being introduced through a conduit having a smaller diameter than the diameter of the water inlet, the conduit terminating adjacent the water inlet and propelling the gases against the inward flow of the water to create a counterflow of water and gas that enhances formation of bubbles in the chamber, an annular constriction being provided around the exterior of the conduit between the conduit's termination adjacent the water inlet and the remainder of the chamber; introducing the contacted water and gases tangentially into a flotation tank to create a circular flow therein; introducing the first and second gases into the flotation tank at a lower level which is below the level at which the water is tangentially introduced into the flotation tank; providing the flotation tank with an upper baffle and a lower baffle, both of which are substantially horizontally disposed in the interior of the tank between a level at which the water is tangentially introduced into the flotation tank and the lower level, the upper baffle having a central opening through which water flows downwardly and the second baffle being a substantially circular plate surrounded by a substantially annular opening through which water flows downwardly in the flotation tank, the lower baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, and the upper baffle being provided with means for retaining beneath it bubbles created by the introduction of the first and second gases into the flotation tank at the lower level, the upper baffle being provided with an upper vent for venting bubbles from beneath the upper baffle to a position adjacent the surface of the water in the flotation tank, the lower baffle being provided with a lower vent for venting bubbles from beneath the lower baffle to a position adjacent the underside of the upper baffle; introducing a portion of the contacted water, which is substantially free of sand, from the flotation tank, into a vacuum vessel to cause a liberation of a portion of the first and second gases dissolved in the water, and to produce a water fraction in the vacuum vessel; removing the water fraction from the vacuum vessel; compressing the gases liberated in the vacuum vessel so that increased pressure condenses water out of the liberated gases; contacting the gases liberated in the vacuum vessel with a desiccant to remove water; reducing the temperature of the gases liberated in the vacuum vessel after they leave the desiccant until one of the gases liquifies, then separating the liquified gas from remaining gas; removing sand from the water in the flotation tank by introducing a portion of the contacted water, containing sand, from the flotation tank into a sump tank where the sand accumulates on the bottom; introducing the first and second gases into the sump tank and contacting the sand with the gases; and skimming oil from the surface of the water in the sump tank, wherein dissolved oil is removed from said surface, and said contacted water separates into a portion which is substantially free of sand, and a portion containing sand.