Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D19/00—Degasification of liquids
  • B01D19/0031—Degasification of liquids by filtration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/025—Reverse osmosis; Hyperfiltration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/04—Feed pretreatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/58—Multistep processes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F9/00—Multistage treatment of water, waste water or sewage
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/027—Nanofiltration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
  • C02F1/004—Processes for the treatment of water whereby the filtration technique is of importance using large scale industrial sized filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/40—Devices for separating or removing fatty or oily substances or similar floating material
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/722—Oxidation by peroxides
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
  • C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/101—Sulfur compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/108—Boron compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/20—Heavy metals or heavy metal compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/32—Hydrocarbons, e.g. oil
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/32—Hydrocarbons, e.g. oil
  • C02F2101/322—Volatile compounds, e.g. benzene
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/32—Hydrocarbons, e.g. oil
  • C02F2101/327—Polyaromatic Hydrocarbons [PAH's]
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/34—Organic compounds containing oxygen
  • C02F2101/345—Phenols
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
  • C02F2103/365—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds from petrochemical industry (e.g. refineries)
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2301/00—General aspects of water treatment
  • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/16—Regeneration of sorbents, filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/04—Aerobic processes using trickle filters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/124—Water desalination
  • Y02A20/131—Reverse-osmosis
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the presently disclosed embodiments are directed to a system and method for treating produced and flow back water and wastewater from processes such as desalting associated with recovery of crude oil and natural gas from reservoirs and the preparation of water to be used for enhance oil recovery (EOR) and other requirements such as desalting and hydrofracturing.
• processes such as desalting associated with recovery of crude oil and natural gas from reservoirs and the preparation of water to be used for enhance oil recovery (EOR) and other requirements such as desalting and hydrofracturing.
• Petroleum also commonly referred to as oil, consists of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds. Petroleum is a naturally occurring liquid found in rock formations. It is generally accepted that oil is formed mostly from the carbon rich remains of ancient plankton after exposure to heat and pressure in the Earth's crust over hundreds of millions of years gradually transforming into oil and natural gas reservoirs. Petroleum is a vital component of the world's supply of energy as a source of providing heating and electricity. It is also used as fuel for vehicles when refined, and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Worldwide consumption of oil is approximately thirty billion barrels (4.8 km 3 ) per year, with developed nations being the largest consumers. For example, the United States consumed about 25% of the oil produced in 2007. Petroleum is found in deep underground natural rock formations and may be associated with other hydrocarbons such as natural gas.
• Oil reservoirs may be located deep within the Earth's crust. As recovery technology advances, oil recovery methods are being performed in deeper locations within the Earth, most notably in offshore and deep ocean locations. For example, deep ocean drilling rigs are now drilling in water depths at or in excess of 2,000 meters. Similarly, there is much activity at land based locations.
• Oil recovery may take a variety of forms and methods. For example, once a reservoir is identified, an oil well is created by drilling a long hole into the Earth. A steel pipe, known as a casing, is placed in the hole to provide structural integrity to the newly drilled well bore. Holes are then made in the base of the well to enable oil to pass into the bore, which oil is then removed by various methods. Typically, recovered oil includes various other secondary byproducts such as natural gas, inorganic compounds and water associated with it. As wells mature, various techniques are employed to extract as much oil as possible. These techniques are commonly referred to as enhanced oil recovery (EOR). One of these techniques injects treated water into a reservoir to displace the oil.
• EOR enhanced oil recovery
• hydraulic fracturing This is a technique used to create fractures in rock with a hydraulic fluid, typically water with additives, under high pressure to release trapped hydrocarbons.
• Crude primary treatment techniques may comprise multistep processes.
• a technique may include first separating byproducts from raw crude oil, followed by desalting the crude oil.
• the byproducts and the raw crude are separated in a device called a separator or dehydrator which removes water.
• separators There are several types of separators depending on the feed stream and the separation objectives.
• Crude oil, natural gas, produced water, bottom sludge which is typically sand, and other inert compounds are separated.
• the oil is then washed with water to remove the salts that are trapped within the crude oil, i.e., desalting.
• the washing removes salts and generates a wastewater stream that contains dissolved salts, suspended material, oil, benzene, ethylbenzene, toluene and xylenes (BETX), and in some cases heavy metals.
• Waste water is generated from the water associated with the recovered hydrocarbons as well as water used to desalt the crude oil.
• the characterization of the water will vary according to its content. As oil and gas production wells mature, there is an increased percentage of produced water being generated. Produced water limits the capacity of crude oil transportation by corroding conveyance systems. [0008] Regulations related to discharge of produced water vary by the authorities involved and the location receiving the waste stream. Table 1 represents typical waste water stream and associated regulatory discharge levels.
• Water used for desalting must meet certain critical parameters set within the industry. Typically the water must be free of suspended solids and low in oxygen, typically below 50 PPB. Depending on the chemical makeup of the crude oil and the amount of salt contamination the total dissolved solids must be controlled to certain maximum concentrations. Light crude typically needs wash water with less than 35,000 PPM, while heavy crude typically need wash water with less than 1,000 PPM. Further processing of the water may occur as need for preparing water used for EOR, hydraulic fracturing or other high purity applications.
• FIG. 6 depicts a known system configuration for a treating water supply 200, e.g., a fresh water source or a salt water source, for subsequent use for desalting, EOR and hydrofracturing operations.
• a treating water supply 200 e.g., a fresh water source or a salt water source
• the system is described as if it is arranged on a water based oil platform.
• Water supply 200 passes through strainer 202 thereby separating a portion of the suspended solids from water supply 200 to form water stream 204. Separated portion of suspended solids 206 is transferred to a platform solids thickening and handling system via output 208.
• Water stream 204 passes through crude filter 210 thereby further separating a portion of the suspended solids from water stream 204 to form water stream 212.
• Crude filter 210 is a common multimedia, disposable media such as cartridge filters, or sand filter capable of handling separation of bulk solids above 10 microns. Separated portion of suspended solids 214 is transferred to a platform solids thickening and handling system via output 208. Next, water stream 212 passes through ultrafine filter 216 thereby further separating a portion of suspended solids from water stream 212 to form water stream 218. Ultrafine filter 216 discharges secondary stream 220 which can be discharged directly into the original water source, e.g., ocean or lake, or alternatively to solids handling operations. Typically ultrafine filters of the type used in known systems, require constant cleaning with chemicals, e.g., chemicals introduced via cleaning system 222. Cleaning chemicals of these types cannot be directly discharged and must be treated or processed onshore. The suspended solids collected at output 208 are transported to shore for disposal or further processing.
• water stream 218 passes to tower degasifer 224 for removal of oxygen.
• Tower degasifers are well known in the art and may include multiple stages of packing. Water is trickled through tower 224 while a vacuum is drawn on the tower via vacuum pump 226 to force oxygen out of water stream 218 to form water stream 228.
• a tower of this type can reduce oxygen levels to less than 50 parts per billion.
• nitrogen generator 230 may feed nitrogen to the tower.
• oxygen scavenger feed 232 may introduce a chemical scavenger, e.g., sodium sulfite, to reduce oxygen to less than 10 parts per billion.
• the foregoing options for treating produced water suffer from the various defects described above, e.g., expensive, complex, difficult to clean, etc.
• the present system and method for treating produced water provides a variety of benefits that have heretofore been lacking in known systems. For example, the present system and method recovers hydrocarbons for commercial value while treating the water for total suspended solids (TSS), oil, metals, H 2 S, BOD and other undesirable components.
• TSS total suspended solids
• the present invention is sufficiently flexible to treat different produced water streams and can accommodate changes in those streams that may occur during operation.
• the present system has a small foot print and minimum weight.
• the present system and method generates minimum secondary waste and solids while being simple and easy to operate.
• the present invention requires minimum consumables and chemicals while producing treated water of a quality that allows for reuse or discharge.
• the present invention provides water for EOR, desalting, hydrofracturing and other production activities wherein the water is treated for the removal of contaminants such as sulfates, barium, boron, total dissolved solids, suspended solids, H 2 S and oxygen, and agents such as biocides are added to prevent sulfate reducing bacteria from reducing sulfates to hydrogen sulfide (H 2 S), for example as need in EOR use.
• the present invention provides secondary waste streams from EOR operations that meet or exceed discharge standards.
• the present invention discussed infra provides a system adapted to condition an initial water feed stream into a treated water stream, the initial water feed stream including at least one of: a plurality of particles; a sulfate; a hardness; a dissolved solid; and, an oxygen.
• the system includes a water cleaning subsystem adapted to treat the initial water feed stream to remove the plurality of particles to form a filtered water stream, and a water reuse subsystem adapted to treat the filtered water stream to remove the sulfate, the hardness, the dissolved solid and/or the oxygen to form the treated water stream.
• the water reuse system includes a sulfate and hardness removal membrane unit adapted to treat the filtered water stream to remove the sulfate and the hardness, and a high pressure reverse osmosis unit adapted to treat the filtered water stream to remove the dissolved solids.
• the water cleaning subsystem includes at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles.
• the water reuse subsystem includes at least one of: a first oxygen removal unit adapted to treat the filtered water stream to remove the oxygen; a second oxygen removal unit adapted to treat the filtered water stream to catalytically remove the oxygen; and, an oxygen scavenger feeder adapted to blend an oxygen scavenger and the filtered water stream.
• the water reuse subsystem includes the second oxygen removal unit, wherein the second oxygen removal unit includes a vessel containing a palladium-doped resin adapted to catalytically remove the oxygen.
• the initial water feed stream includes ocean water, a fresh water source and/or a pre-treated produced water.
• the present invention broadly provides a system adapted to condition an initial water feed stream into a treated water stream, the initial water feed stream includes at least one of: a plurality of particles; a sulfate; a hardness; a dissolved solid; and, an oxygen.
• the system includes a water cleaning subsystem adapted to treat the initial water feed stream to remove the plurality of particles to form a filtered water stream, and a water reuse subsystem adapted to treat the filtered water stream to remove the sulfate, the hardness, the dissolved solid and/or the oxygen to form the treated water stream.
• the water reuse system includes a first oxygen removal unit adapted to treat the filtered water stream to remove the oxygen, and a second oxygen removal unit adapted to treat the filtered water stream to catalytically remove the oxygen.
• the water cleaning subsystem includes at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles.
• the water reuse subsystem includes at least one of: a sulfate and hardness removal membrane unit adapted to treat the filtered water stream to remove the sulfate and the hardness; a high pressure reverse osmosis unit adapted to treat the filtered water stream to remove the dissolved solids; and, an oxygen scavenger feeder adapted to blend an oxygen scavenger and the filtered water stream.
• the second oxygen removal unit includes a vessel containing a palladium-doped resin adapted to catalytically remove the oxygen.
• the initial water feed stream comprises ocean water, a fresh water source and/or a pre-treated produced water.
• the present invention broadly provides a system adapted to condition an initial water feed stream into a treated water stream, the initial water feed stream at includes least one of: a plurality of particles; a sulfate; a hardness; a dissolved solid; and, an oxygen.
• the system includes a water cleaning subsystem adapted to treat the initial water feed stream to remove the plurality of particles to form a filtered water stream, and a water reuse subsystem adapted to treat the filtered water stream to remove the sulfate, the hardness, the dissolved solid and/or the oxygen to form the treated water stream.
• the water reuse system includes a sulfate and hardness removal membrane unit adapted to treat the filtered water stream to remove the sulfate and the hardness, a high pressure reverse osmosis unit adapted to treat the filtered water stream to remove the dissolved solids, a first oxygen removal unit adapted to treat the filtered water stream to remove the oxygen, and a second oxygen removal unit adapted to treat the filtered water stream to catalytically remove the oxygen.
• the water cleaning subsystem includes at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles.
• the water reuse subsystem further includes an oxygen scavenger feeder adapted to blend an oxygen scavenger and the filtered water stream.
• the second oxygen removal unit includes a vessel containing a palladium-doped resin adapted to catalytically remove the oxygen.
• the initial water feed stream includes ocean water, a fresh water source and/or a pre-treated produced water.
• the present invention broadly provides a system adapted to condition an initial water feed stream into a treated water stream, the initial water feed stream including at least one of: a sulfate; a hardness; a dissolved solid; and, an oxygen.
• the system includes a sulfate and hardness removal membrane unit adapted to treat the initial water feed stream to remove the sulfate and the hardness, a high pressure reverse osmosis unit adapted to treat the initial water feed stream to remove the dissolved solids, a first oxygen removal unit adapted to treat the initial water feed stream to remove the oxygen, and a second oxygen removal unit adapted to treat the initial water feed stream to catalytically remove the oxygen.
• the initial water feed stream further includes a plurality of particles and the system includes at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles.
• the system further includes an oxygen scavenger feeder adapted to blend an oxygen scavenger and the initial water feed stream.
• the second oxygen removal unit includes a vessel containing a palladium-doped resin adapted to catalytically remove the oxygen.
• the initial water feed stream includes ocean water, a fresh water source and/or a pre-treated produced water.
• the present invention discussed infra provides a system adapted to condition an initial water feed stream into a treated water stream and to discharge the treated water stream.
• the initial water feed stream includes at least one of: a plurality of particles; an oil; a volatile organic compound; a hydrogen sulfide; a non-volatile compound; a heavy metal; and, a dissolved ion.
• the system includes a particle and oil removal subsystem adapted to treat the initial water feed stream to remove the plurality of particles and the oil to form a first partial treated water stream, a chemical oxygen demand reduction subsystem adapted to treat the first partial treated water stream to remove the volatile organic compound, the hydrogen sulfide and/or the non-volatile organic compound to form a second partial treated water stream, and further includes a heavy metal and dissolved ion removal subsystem adapted to treat the second partial treated water stream to remove the heavy metal and the dissolved ion to form a treated water stream.
• the particle and oil removal subsystem includes at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; an oil coalescer unit adapted to treat the initial water feed stream to remove the oil; a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, an oil removal membrane unit adapted to treat the initial water feed stream to remove the oil.
• the chemical oxygen demand reduction subsystem includes at least one of: a stripping unit adapted to treat the first partial treated water stream to remove the volatile organic compound and the hydrogen sulfide and to form a vapor phase comprising the volatile organic compound and the hydrogen sulfide; and, a hydrocarbon polishing unit adapted to treat the first partial treated water stream to remove the non-volatile organic compound.
• the chemical oxygen demand reduction subsystem includes the stripping unit, and further includes at least one of: a bio scrubber unit adapted to metabolize the volatile organic compound and the hydrogen sulfide of the vapor phase; and, a flare or a thermal oxidizer adapted to combust the volatile organic compound and the hydrogen sulfide of the vapor phase.
• the heavy metal and dissolved ion removal subsystem includes at least one of: a heavy metal and dissolved ion removal unit adapted to treat the second partial treated water stream to adsorb the heavy metal and the dissolved ion and to form a plurality of adsorbed heavy metals and a plurality of adsorbed dissolved ions; a heavy metal and dissolved ion precipitation unit adapted to precipitate the plurality of adsorbed heavy metals as a plurality of insoluble metal hydroxides and the plurality of adsorbed dissolved ions as a plurality of insoluble compounds; and, a filter press adapted to form at least one cake comprising the plurality of insoluble metal hydroxides and the plurality of insoluble compounds.
• the present invention system is further adapted to prepare the treated water stream for an enhanced oil recovery operation, the treated water stream including at least one of: a sulfate; a hardness; a dissolved solid; and, an oxygen.
• the system further includes a water reuse subsystem adapted to treat the treated water stream to remove the sulfate, the hardness, the dissolved solid and/or the oxygen to form an enhanced oil recovery feed stream.
• the water reuse subsystem includes at least one of: a sulfate and hardness removal membrane unit adapted to treat the treated water stream to remove the sulfate and the hardness; a high pressure reverse osmosis unit adapted to treat the treated water stream to remove the dissolved solid; an oxygen removal unit adapted to treat the treated water stream to remove the oxygen; and, an oxygen scavenger feeder adapted to blend an oxygen scavenger and the treated water stream.
• the present invention system further includes a water cleaning subsystem adapted to treat an unconditioned cleaning water feed stream to remove a plurality of particles to form a conditioned cleaning water feed stream, wherein the conditioned cleaning water feed stream is used by at least one of: the particle and oil removal subsystem; the chemical oxygen demand reduction subsystem; and, the heavy metal and dissolved ion removal subsystem.
• the water cleaning subsystem includes at least one of: a gross particle filter adapted to treat the unconditioned cleaning water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the unconditioned cleaning water feed stream to remove the plurality of particles.
• the unconditioned cleaning water feed stream includes ocean water or a fresh water source.
• a method for conditioning an initial water feed stream into a treated water stream includes at least one of: a plurality of particles; an oil; a volatile organic compound; a hydrogen sulfide; a non-volatile compound; a heavy metal; and a dissolved ion.
• the method includes: a) treating the initial water feed stream to remove the plurality of particles and the oil to form a first partial treated water stream; b) treating the first partial treated water stream to remove the volatile organic compound, the hydrogen sulfide and/or the heavy metal to form a second partial treated water stream; and, c) treating the second partial treated water stream to remove the heavy metal to for the treated water stream.
• the step of treating the produced water feed stream is performed using at least one of: a gross particle filter adapted to treat the initial water feed stream to remove the plurality of particles; an oil coalescer unit adapted to treat the initial water feed stream to remove the oil; a fine particle filter adapted to treat the initial water feed stream to remove the plurality of particles; and, an oil removal membrane unit adapted to treat the initial water feed stream to remove the oil.
• the step of treating the first partial treated water stream is performed using at least one of: a stripping unit adapted to treat the first partial treated water stream to remove the volatile organic compound and the hydrogen sulfide and to form a vapor phase comprising the volatile organic compound and the hydrogen sulfide; and, a chemical oxygen demand polishing unit adapted to treat the first partial treated water stream to remove the non-volatile organic compound.
• the step of treating the first partial treated water stream is performed using the stripping unit and at least one of: a bio scrubber unit adapted to metabolize the volatile organic compound and the hydrogen sulfide of the vapor phase; and, a flare or a thermal oxidizer adapted to combust the volatile organic compound and the hydrogen sulfide of the vapor phase.
• a bio scrubber unit adapted to metabolize the volatile organic compound and the hydrogen sulfide of the vapor phase
• a flare or a thermal oxidizer adapted to combust the volatile organic compound and the hydrogen sulfide of the vapor phase.
• the step of treating the second partial treated water stream is performed using at least one of: a heavy metal and dissolved ion removal unit adapted to treat the second partial treated water stream to adsorb the heavy metal and the dissolved ion and to form a plurality of adsorbed heavy metals and a plurality of adsorbed dissolved ions; a heavy metal and dissolved ion precipitation unit adapted to precipitate the plurality of adsorbed heavy metals as a plurality of insoluble metal hydroxides and the plurality of adsorbed dissolved ions as a plurality of insoluble compounds; and, a filter press adapted to form at least one cake comprising the plurality of insoluble metal hydroxides and the plurality of insoluble compounds.
• a heavy metal and dissolved ion removal unit adapted to treat the second partial treated water stream to adsorb the heavy metal and the dissolved ion and to form a plurality of adsorbed heavy metals and a plurality of adsorbed dissolved ions
• the treated water stream includes at least one of: a sulfate; a hardness; a dissolved solid; and, an oxygen
• the method further includes: d) treating the treated water stream to remove the sulfate, the hardness, the dissolved solid and/or the oxygen to form an enhanced oil recovery feed stream.
• the step of treating the treated water stream is performed using at least one of: a sulfate and hardness removal membrane unit adapted to treat the treated water stream to remove the sulfate and the hardness; a high pressure reverse osmosis unit adapted to treat the treated water stream to remove the dissolved solids; an oxygen removal unit adapted to treat the treated water stream to remove the oxygen; and, an oxygen scavenger feeder adapted to blend an oxygen scavenger and the treated water stream.
• a sulfate and hardness removal membrane unit adapted to treat the treated water stream to remove the sulfate and the hardness
• a high pressure reverse osmosis unit adapted to treat the treated water stream to remove the dissolved solids
• an oxygen removal unit adapted to treat the treated water stream to remove the oxygen
• an oxygen scavenger feeder adapted to blend an oxygen scavenger and the treated water stream.
• the method further include: treating an unconditioned cleaning water feed stream to remove a plurality of particles to form a conditioned cleaning water feed stream, wherein the conditioned cleaning water feed stream is used in at least one of: steps a), b) and c).
• the step of treating an unconditioned cleaning water feed stream is performed using at least one of: a gross particle filter adapted to treat the unconditioned cleaning water feed stream to remove the plurality of particles; and, a fine particle filter adapted to treat the unconditioned cleaning water feed stream to remove the plurality of particles.
• the unconditioned cleaning water feed stream includes ocean water or a fresh water source.
• Figure 1 is a first portion of a schematic diagram of a present invention system for treating produced water showing a clean water production subsystem
• Figure 2 is a second portion of a schematic diagram of a present invention system for treating produced water showing a particle and oil subsystem
• Figure 3 is a first portion of a schematic diagram of a present invention system for treating produced water showing a chemical oxygen demand reduction subsystem
• Figure 4 is a first portion of a schematic diagram of a present invention system for treating produced water showing a heavy metal removal subsystem
• Figure 5 is a first portion of a schematic diagram of a present invention system for treating produced water showing a water reuse subsystem
• Figure 6 is a schematic diagram of a known desalting system.
• Figure 7 is a schematic diagram of an alternate embodiment of present invention system for treating a water supply for subsequent use.
• the term “average” shall be construed broadly to include any calculation in which a result datum or decision is obtained based on a plurality of input data, which can include but is not limited to, weighted averages, yes or no decisions based on rolling inputs, etc.
• produced water is intended to mean water that is produced when oil and gas are extracted from the ground. Oil and gas reservoirs have a natural water layer, i.e., formation water, that lies under the hydrocarbons. Oil reservoirs frequently contain large volumes of water, while gas reservoirs tend to have smaller quantities.
• produced water is intended to include water commonly known as flow back water used in hydrofracturing operations, as well as water used in desalting operations.
• Pre-treated produced water is intended to mean produced water that has been treated by some or all of the subsystems described infra which occur prior to the water reuse subsystem.
• to treat...to remove is intended to mean performing an operation on a component to remove all or some of a constituent within the component, wherein the extent of partial removal is further described infra
• to treat...to adsorb is intended to mean performing an operation on a component to adsorb all or some of a constituent within the component, wherein the extent of partial adsorption is further described infra.
• a device comprising at least one of: a first element; a second element; and, a third element is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element.
• a device comprising a first element, a second element and/or a third element is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element.
• the present invention recovers hydrocarbons of commercial value by limiting use of chemicals that would prevent such recovery.
• the present invention treats produced water for TSS, oil, metals, H 2 S, BOD, COD and other contaminates that would prevent discharge of the treated water to the environment.
• the present invention is flexible in that it can be adjusted as needed to treat different streams and changes within a given stream.
• the present invention has a small foot print with minimum weight when compared to known systems of gravity and induced gas separation, nut shell filtration, metals precipitation, and biological treatment.
• the present invention causes minimum secondary and solids waste generation, while utilizing a minimum amount of consumables and chemicals.
• the present invention produced treated water of a quality that allows for reuse and/or discharge.
• the present invention provides water for EOR, desalting, hydrofracturing or other production clean water requirements where the water is treated for the removal of sulfates, suspended solids, dissolved solids, H 2 S, and oxygen, while agents such as biocides are added to prevent sulfate reducing bacteria from reducing sulfates to hydrogen sulfide (H 2 S) where required.
• the present system and method broadly comprises: filtration pretreatment; hydrocarbon removal; volatile organic compound (VOC) and H 2 S removal; metals and specific ion contaminate removal; solids dewatering; and, discharge.
• the present invention may also prepare water for use in EOR, clean water production uses or hydrofracturing, and thus may broadly comprise: nano filtration; low and high pressure reverse osmosis; and, degasification.
• the present invention comprises a two step, high rate, compact filtration stage.
• the first step provides for crude filtration for sand and solids removal while the second step removes finer particles that may cause fouling of oil recovery membranes or reduced recovery rates.
• the second step is performed after the primary oil recovery step. Crude filtration is performed in using a gross particle filter, while fine filtration is performed in a fine particle filter. Both filtration steps may include a pneumatic assist for water flush cleaning. Filtration media types and sizes are adjusted as required for process optimization.
• the first filtration step may be a slotted duplex stainless steel wedge wire with openings of 200 microns to remove fine sand. After the water leaves the primary oil separation device any entrained particles will be removed by the polishing filter using a 20 micron cleanable filter cloth media made from Teflon®.
• Pneumatic gas assist is used to dislodge any sticky material from the filter surface.
• a cleaning water stream is returned to a dehydrator, i.e., an upstream system forming part of the crude oil processing system, wherein oil recovery is accomplished, or the cleaning water stream can be sent to a stilling tank for separation of oil and solids.
• the solids can then be sent to a dewatering system, such as a J-Press® filter press sold by Siemens located in Alpharetta, Georgia.
• the present invention comprises a two step process for the efficient removal of the majority of hydrocarbons present in the produced water stream.
• This inventive process is highly efficient within a small foot print or surface area consumed. Hydrocarbons are recovered for commercial use since chemicals are not used that would prevent recovery and use of oil. It should be appreciated that the present two step process allows for high recoveries, typically in excess of 95%.
• the first step of the hydrocarbon removal stage comprises the primary oil separation and recovery operation.
• This step utilizes a vessel filled with a resin bead packing that attracts fine oil droplets on its surface. As the droplets grow in size, they release and float to the top of vessel. The layer of oil forming at the top of the vessel is removed and recovered for commercial value. Recovery of oil can be as high as 95% with residual oil of less than 5 parts per million (PPM) in the water stream.
• PPM parts per million
• the water exiting the separator can be directly discharged to the environment where conditions allow. However, it should be appreciated that whether the water is directly discharged or further processed is based on the quality of the feed stream and the discharge standards for the application or location.
• the resin separator system can be run at higher temperatures, e.g., 70°C or higher, to prevent paraffin and asphaltene from coating the vessel or resin beads.
• the high surface area afforded by the resin beads permits the overall size of the separator system to be relatively small and light weight.
• the separator system may comprise one or more vessels, and the feed stream may be introduced under pressure or gravity fed through the separator. Moreover, the feed stream may flow upwardly or downwardly through the separator.
• the present resin separator system permits fouled media, i.e., fouled resin beads, to be cleaned in place or removed for external cleaning. Cleaning is accomplished by up flow fluidizing the resin bed and/or the addition of hot water to remove waxes and particulates. The layer of oil forming at the top of the vessel is removed and recovered for commercial value.
• the second step of the hydrocarbon removal stage comprises at least one membrane separation operation. It should be appreciated that the filtration pretreatment stage and primary oil recovery stage increase and/or optimize the performance of the membrane separation operation.
• the membranes used in the second step of the hydrocarbon removal stage remove the balance of free oil and additional hydrocarbons such as BETX compounds from the feed stream. The foregoing is accomplished by allowing oil to build up to over 1,000 PPM within the membrane. As oil levels increase within the membrane, additional hydrocarbons are removed thus decreasing the BOD and COD load on additional treatment devices and providing for the additional recovery of hydrocarbons.
• Suitable membranes may be selected from but not limited to hydrophilic membranes, polyacrylonitrile (PAN) polymer, polyvinylidene fluoride (PVDF) and polyvinyl chloride (PVC). Membranes having pore sizes between 0.01 - .05 microns with an approximate molecular weight cutoff between 10K - 60K Daltons are suitable for use in the present invention. It should be appreciated that suitable membranes are hydrophilic which attract water and repel oil, and the level of hydropholicity may be specifically selected based on the requirements of the membrane separation operation. The hydrophilic characteristic of the membrane allows for low tangential surface velocities thereby saving on pumping horse power.
• Some membranes e.g., PVDF
• PVDF can be run at hot temperatures, i.e., 70°C or higher, to prevent paraffin and asphaltene from coating the membranes.
• These membranes are design so that TDS will not be affected by the process. In short, by minimizing rejection of TDS, low pressure and high flux rate can be achieved through the membranes without introducing scaling issues.
• the VOC and H 2 S removal stage comprises air stripping of these components using conventional, known techniques.
• the water feed stream flows down though packaging material or a series of trays while air is introduced via a counter current up flow.
• This arrangement removes a substantial amount of VOCs and H 2 S from the water feed stream thereby reducing the load to the final semi volatile organic compound (SVOC) removal device.
• SVOC semi volatile organic compound
• a tray type air stripper as described is compact in size and provides VOC and H 2 S removal to acceptable levels.
• Other gas/liquid contacting devices known in the art may be utilized for the VOC and H 2 S removal stage, e.g., columns with random or structured packing.
• the air stripping device may comprise a biogas filter adapted to destroy VOCs and H 2 S in the off gas from the stripper, thus permitting direct air discharge as the exiting air stream meets acceptable air discharge standards.
• the biogas filter uses a high surface ceramic media that is hydrophilic. The media provides high surface area and flow throughput for the air, which provides increased contact with bacteria specifically selected to destroy, in an aerobic process, VOCs using chemoheterotophic bacteria and H 2 S using sulfur-oxidizing bacteria.
• Biofilters are reactors in which waste gases are allowed to pass through a porous packed bed material immobilized with suitable microbial cultures.
• the contaminants in the gas transverse to the liquid phase surrounding the microbial biofilm in the media.
• the contaminants are subsequently converted to C0 2 , H 2 0, S0 4 , inorganic salts and biomass by microorganisms.
• the high surface area of the media permits the unit to have a small overall footprint and low weight.
• a final oil recovery step may comprise passing the feed stream through a specially design adsorptive resin or granular activated carbon which adsorb final traces of hydrocarbons.
• resins e.g., macroporous styrene-DVB, and activated carbon have a high infinity for organic compounds and thus readily adsorb organic compounds.
• the foregoing oil recovery unit can be in upstream or downstream of the air stripper described above.
• the final oil recovery unit may be regenerated with steam to desorb hydrocarbons and any captured hydrocarbons can be recovered therefrom.
• the foregoing media i.e., resins and/or activated carbon, are held in pressure vessels in various series and/or parallel configurations as required by particular system needs.
• Produced water typically comprises various types of heavy metals and/or other dissolved contaminate ions that have restrictions for discharge, e.g., lead, copper, cadmium, mercury, strontium and barium.
• Specific resins used for the removal of metals and other dissolved ion contaminants, e.g., boron are designed to work in concentrated brine salt streams, e.g., macroporous styrene divinylbenzene with iminodiacetic acid functional groups and a macroreticular polymer with thiol functional groups.
• a N- methylglucimine functional group can be used.
• the foregoing media i.e., resins
• the foregoing media i.e., resins
• resins are held in pressure vessels in various series and/or parallel configurations as required by particular system needs.
• metals and dissolved specific ion contaminates can be removed from the produced water stream and then during resin regeneration using acids and hydroxides, a very concentrated stream of metals and contaminates can be generated.
• the metals in the regeneration stream can be precipitated using hydroxide which is added to adjust the pH of collected solution to the appropriate range for heavy metal precipitation as insoluble metal hydroxides along with other insoluble contaminates. Heavy metal precipitates may be subsequently dewatered into a cake as described infra.
• Other chemistry which is common to the art can be used and additives such as filtering acids can be used.
• the present invention process is very efficient relative to conventional precipitation clarification processes, and generates far less sludge while maintaining a smaller overall footprint.
• the resulting water can be further treated with the addition of an oxidizing agent to remove traces of BOD, COD and 3 ⁇ 4S.
• oxidizing agents can include but are not limited to, chlorine, ozone and peroxide, which agents can be generated locally or supplied from an outside source.
• a reaction tank, reactor mixer, polymer, chemical feed for pH adjustment and filter press is included in the present system for precipitation of solids and removal of water prior to transportation to a disposal location.
• the reaction tank in combination with the filter press can also be used for dewatering solids from filtration stages describe supra.
• One benefit of the present invention is that water from the process can be directly discharged to an ocean or other body of water. If the TDS level or temperature is not within discharge requirements, the wastewater is discharged below surface, and depending on the wastewater chemistry, discharged in a deep distribution/dilution pipeline or deep well waste injection.
• One of the aspects of the present invention is that water from a fresh water or seawater treatment system can be fed directly to this subsystem for preparation for enhanced oil recovery (EOR), desalting, water for production activities and/or hydrofracturing in whole or in part depending on the subsystems demands. For example, should the volume of produced water decrease or stop entirely, processing of water for the foregoing operations can continue.
• EOR enhanced oil recovery
• the processed water goes through a secondary treatment stage to allow for reuse in EOR, desalting, water for production activities and/or hydrofracturing. It should be appreciated that water used for EOR must be free of suspended solids, sulfates, oxygen, boron, barium and strontium. Additionally, a biocide is often added to prevent biological attack on any recovered oil.
• the processed water goes through an additional treatment stage to allow for reuse in low total dissolved solids (TDS) EOR, desalting, water for production activities and/or hydrofracturing. It should be appreciated that water used for these operations must be free of various contaminated such as suspended solids, sulfates, oxygen, barium and strontium, and must have low TDS. Additionally, a biocide is often added to prevent biological attack on any recovered oil.
• TDS total dissolved solids
• Preparation of water for use in EOR comprises nano filtration of the water stream.
• Nano filtration is accomplished using a low pressure nano filtration process with a membrane.
• Suitable membranes e.g., reverse osmosis membrane elements designed to allow monovalent ions such as sodium and chloride to pass through as permeate, are designed specifically for the removal of large ions, typically divalent such as sulfates, hardness, barium and strontium.
• the membranes are run at low pressures and do not remove general TDS such as sodium and chloride.
• further filtration of the water is necessary prior to use in EOR, desalting and/or hydrofracturing, i.e., where low TDS water is required.
• alternate forms of reverse osmosis filtration occur. Salinity removal from the water is accomplished using a high pressure, high rejection membrane designed for streams comprising monovalent ions such as sodium and chloride, e.g., high pressure reverse osmosis membrane elements, as described in greater detail infra. Where feasible, energy is recovered from the reverse osmosis brine stream and returned to the feed stream.
• preparation for use of water in EOR, desalting or hydrofracturing comprises a degasification stage.
• a special membrane is used to remove oxygen from the water.
• the membrane is a hydrophobic thin film composite of polydimethysilicon (PDMS) on a polysulfone base.
• PDMS polydimethysilicon
• the membrane has a bubble point of approximately 300 psi.
• the membrane does not let water pass through, i.e., the membrane only allows gases to pass.
• the membrane can remove up to 99% of the oxygen in the feed stream, while operating at a feed pressure of 50-200 psi and temperature of up to 77°C.
• the combination of using a vacuum pump on the gas side of the membrane and nitrogen sweep gas causes the removal of (3 ⁇ 4 to less than 50 parts per billion (PPB).
• the system comprises further oxygen removal from the water stream.
• a polishing resin device can be used to further reduced oxygen in the water.
• the water is passed through a pressurized vessel at approximately 50-150 psi holding a weakly basic, macroporous, palladium-doped, polymer based resin in the form of spherical beads.
• the oxygen is catalytically removed from the water in the presence of a suitable reducing agent such as hydrogen. Hydrogen is introduced to the vessel under pressure and is dissolved in the water to be treated and then passed through the resin bed.
• Residual oxygen concentrations of less than 20 ppb can be obtained at flow rates up to a superficial velocity of 80 meters per hour at temperatures up to 120°C.
• an oxygen removal agent such as hydrazine may be used for final polishing and removal of O2.
• the present invention comprises groupings of elements into subsystems.
• the present invention broadly comprises the following grouped subsystems in various combinations: water cleaning; particle and oil removal; chemical oxygen demand reduction; heavy metal removal; and, water reuse.
• Figures 1 through 5 depict a typical embodiment of a present invention system for treating produced water. It should be noted that in order to depict the present invention with sufficient detail in the figures, the system was broken in to portions and distributed across Figures 1 through 5. The connections between the separate portions are represented by encircled letters. For example, one connection between Figure 1 and Figure 2 is shown by the encircled ' ⁇ '.
• Water cleaning subsystem 10 receives unconditioned cleaning water feed stream 12, e.g., ocean water or other water supply such as a fresh water, and passes water feed stream 12 through gross particle filter 14 thereby removing large particulate matter.
• water feed stream 12 is pumped through water cleaning subsystem 10 as described infra relative to particle and oil removal subsystem 16.
• gross particle filter 14 is a self-cleaning tubular backwash filter such as the strainers manufactured by SAMCO Technologies, Kinney, RP Adams, DOW TequaticTM plus.
• Gross particle filter 14 is fitted with a 100-200 micron wedgewire filter element. Other filtration or solids liquid separation technologies may also be used for large particulate removal, such as a disc filter or centrifuge.
• Gross particle filter 14 is arranged to be backwashed with filtered water from the unit. The backwash wastewater is returned to the source of water feed stream 12, e.g., an ocean, via outlet 18.
• fine particle filter 22 is a self- cleaning tubular backwash filter such as the tubular filter manufactured by SAMCO Technologies.
• Fine particle filter 22 is fitted with a 10-20 micron media which may be a Teflon®, polypropylene, nylon or metal cloth filter element.
• Other filtration or solids liquid separation technologies may be used for fine particulate removal, such as a disc filter, cartridge filter, or bag filter.
• Fine particle filter 22 is designed to be backwashed with filtered water from the unit.
• Pneumatic gas assist can be used to dislodge any sticky material from the filter surface. Air is compressed with line pressure into a dome on the device and expanded when the pressure is relieved during backwash. The backwash wastewater is returned to the source of water feed stream 12, e.g., an ocean, via outlet 24.
• the water stream exiting fine particle filter 22 is conditioned cleaning water feed stream 26 which, in some embodiments, is used in particle and oil removal subsystem 16, chemical oxygen demand reduction subsystem 28, heavy metal and dissolved ion removal subsystem 30, water reuse subsystem 118 and/or oxidizing agent feed stream 94. It should be appreciated that chemical and biological oxygen demand levels are reduced by a reduction or removal of hydrocarbons, volatile gases, non-volatile gases and H 2 S, and that chemical oxygen demand reduction subsystem 28 is used to reduce or remove all or some of these contaminants.
• Particle and oil removal subsystem 16 receives initial water feed stream 32 from a plant oil dehydrator, desalter (not shown) or other produced water generators such as flow back from a hydrofracturing operation.
• Feed stream 32 is pumped to gross particle filter 34 at a pressure of approximately 50 to 150 pounds per square inch gauge (psig) thereby removing large particulate matter.
• gross particle filter 34 is a self-cleaning tubular backwash filter such as the strainers manufactured by SAMCO Technologies, Kinney, RP Adams, DOW TequaticTM plus.
• Gross particle filter 34 is fitted with a 100-200 micron wedgewire filter element.
• filtration or solids liquid separation technologies may also be used for large particulate removal, such as a disc filter or centrifuge.
• Gross particle filter 34 is arranged to be backwashed with filtered water from the unit.
• the backwash wastewater is returned via outlet 36 to the dehydrator or stilling tank where solids and attached hydrocarbons settle out and can be removed as sludge or recovered.
• backwash wastewater may be sent back to precipitation unit 104, separated and the solids dewatered.
• Filtered water 38 from gross particle filter 34 comprises very small oil droplets.
• Filtered water 38 flows to coalescer unit 40 for oil removal. Due to the small size of oil droplets, the oil will not separate from filtered water 38 in a traditional gravity separator without assistance.
• Coalescer unit 40 comprises a multi chamber vessel or pair of single chamber vessels, designed for either atmospheric or pressure operation. These units are custom designed for each application.
• a suitable coalescer unit can be obtained from SAMCO Technologies located in Buffalo, New York.
• the first chamber or vessel holds a bed of coalescing media.
• the coalescing media is AmberliteTM ROC1 10 manufactured by Dow Chemical Company.
• coalescing media attracts the very small oil droplets and allows them to agglomerate into larger oil droplets that then float to the top of the water in the second chamber or vessel, similar to a traditional gravity separator.
• the floating oil phase is returned to the dehydrator or other suitable collection device for recovery via outlet 42.
• Fouling by contaminants such as particles and paraffin can occur. Removal of contaminants is accomplished by internal or external reverse flow/fluidizing of the coalescing media bed and/or hot water stripping of the media bed.
• coalescer unit 40 may require the use of additional water, i.e., conditioned cleaning water feed stream 26.
• coalescer unit 40 recovery of oil in coalescer unit 40 may be as high as 95% with residual oil as low as 5 ppm in the water stream.
• the water exiting the separator can be directly discharged to the environment where conditions allow. However, it should be appreciated that whether the water is directly discharged or further processed is based on the quality of the feed stream and the discharge standards for the application or location.
• Fine particle filter 46 Water feed 44 exiting the separating chamber or vessel of coalescer unit 40 is transferred to fine particle filter 46 at a pressure of approximately 50 to 150 psig using pump 48, if required, wherein particulate matter with sizes ranging from 10-100 microns is removed.
• fine particle filter 46 is a self-cleaning tubular backwash filter such as the tubular filter manufactured by SAMCO Technologies. Fine particle filter 46 is fitted with a 10-50 micron media which may be a Teflon®, polypropylene, nylon or metal cloth filter element. Other filtration or solids liquid separation technologies may be used for fine particulate removal, such as a disc filter, cartridge filter, or bag filter.
• Fine particle filter 46 is designed to be backwashed with filtered water from the unit.
• the backwash wastewater is returned via outlet 50 to the dehydrator or stilling tank where solids settle out and can be removed as sludge.
• Fine particle filter 46 comprises a dome for trapping and compression of air to allow for pneumatic cleaning assist.
• Water stream 52 exiting fine particle filter 46 may containing trace amounts of free and emulsified oil. Water stream 52 flows to oil removal membrane unit 54 for further removal of oil. In some embodiments, water stream 52 is transferred to membrane unit 54 using pump 56. It should be appreciated that depending system needs, only one of pumps 48 and 56 will be included, e.g., a single pump may be sized to be sufficient for the needs of the removal subsystem 16. Oil removal membrane unit 54 is an array of pressure rated housings filled with spiral wound or hollow fiber membrane modules, the number and arrangement of which are dictated by the water flow rate to yield a permeate water flow rate of 5-20 gallons/minute/square foot of membrane.
• the membrane elements are hydrophilic polyacrylonitrile (PAN) polymer, PVDF, or PVC.
• PAN polyacrylonitrile
• the oil adsorbs BETX compounds thus reducing the COD and BOD in the water. If the membrane requires cleaning, hot water and/or caustic compounds may be flushed through the membranes or externally clean the membranes in place within system.
• Chemical oxygen demand reduction subsystem 28 receives low pressure permeate stream 58 from oil removal membrane unit 54 which stream 58 flows to stripping unit 62 for removal of volatile organic compounds (VOC) and hydrogen sulfide (H 2 S) to reduce chemical oxygen demand (COD) of the water.
• Stripping unit 62 is a conventional countercurrent gas/liquid contacting tower filled with random or structured packing well known to those skilled in the art, e.g., Jaeger Tri-Packs® or a low profile tray type.
• Water stream 58, rich in VOC and H 2 S, enters the top of stripping unit 62 and flows downward through the packing or trays.
• Clean atmospheric air stream 64 is introduced into the bottom of stripping unit 62 via blower 66 and flows upwardly.
• Vapor phase stream 68 exits the top of the unit, i.e., stripping unit 62, and water stream 70, lean in VOC and H 2 S, exits the bottom of the unit, i.e., stripping unit 62.
• An example of a suitable stripping unit 62 is a convention tower type stripping unit such as the stripping unit sold by Delta Cooling Towers, inc. located in Rockaway, New Jersey, or the shallow tray compact type sold by Bisco Environmental located in Taunton, Massachusetts.
• the VOC and H 2 S rich vapor phase flows to gas flare 72.
• Gas flare 72 is also commonly known in the art as a flare and a flare stack, and may, in some embodiments, be a thermal oxidizer.
• vapor phase stream 68 flows to bio scrubber unit 74 for treatment, e.g., reducing carbon content, to allow discharge to atmosphere meeting regulatory limits.
• bio scrubber unit 74 is a conventional contacting tower filled with BioVastTM or MP2C, a porous, hydrophilic, high surface area flow through ceramic packing manufactured by CerMediaTM LLC located in Buffalo, New York.
• the media provides high surface area and flow throughput for the air, which provides increased contact with microorganisms that are generally indigenous to the region where the unit resides and may include any species of heterotrophic bacteria that inoculate the media and adapt to destroy, in an aerobic process, VOCs and H 2 S.
• Biofilters are reactors in which waste gases are allowed to pass through a porous packed bed material immobilized with suitable microbial cultures. As the waste gas passes through the filter medium, the contaminants in the gas transverse to the liquid phase surrounding the microbial biofilm in the medium where they are degrade to CO 2 , H 2 0, S0 4 , inorganic salts and biomass by microorganisms.
• the high surface area of the media permits the unit to have a small overall footprint and low weight.
• Conditioned cleaning water stream 26 obtained from an ocean or other available clean water source as described supra, is trickled across the top of the packing material for humidity and water wetting control. Water stream 26 is sprayed over the packing material at a rate necessary to maintain saturated packing material while flushing away treated byproducts. Packing material size is selected to cause an empty bed contact of between 5 - 60 seconds. VOC and I3 ⁇ 4S rich vapor, i.e., vapor phase stream 68, flows into the bottom of the tower of bio scrubber unit 74 and upwardly through the packing material.
• the preferred packing material is a very porous ceramic media which has extremely high surface area.
• the surface of the packing material is covered with a biofilm of naturally occurring microorganisms that metabolize VOCs and I3 ⁇ 4S to carbon dioxide, water, and sulfates which can be safely discharged to the atmosphere or ocean.
• Naturally occurring bacteria that provide biochemical destruction of VOCs and I3 ⁇ 4S. Examples include but are not limited to chemoheterotophic bacteria and sulfur oxidizing bacteria.
• Water stream 76 is discharged to an ocean or other suitable discharge location and treated air stream 78 is discharged to the atmosphere.
• Water stream 70 which exits from the bottom of stripping unit 62, flows to hydrocarbon polishing unit 80 for removal of dissolved, non-volatile organic compounds, e.g., phenols and polycyclic aromatic hydrocarbons (PHA), to recover additional hydrocarbons and to further reduce COD of water stream 70 to make it suitable for disposal or reuse.
• water stream 70 is transferred to polishing unit 80 using pump 82.
• hydrocarbon polishing unit 80 comprises two standard ASME pressure vessels filled with synthetic adsorbent resin. The pressure vessels may be arranged in various series and parallel configurations.
• a suitable synthetic adsorbent resin is the styrene-DVB macroporous material DowexTM OptiporeTM L493 manufactured by Dow Chemical Company located in Midland, Michigan.
• Other adsorptive media such as activated carbon, e.g., activated carbon sold by Calgon Carbon located in Pittsburgh, Pennsylvania, may be utilized in hydrocarbon polishing unit 80.
• activated carbon e.g., activated carbon sold by Calgon Carbon located in Pittsburgh, Pennsylvania
• the vessels that form hydrocarbon polishing unit 80 are arranged in series or parallel with the first vessel removing the largest portion, and possibly all, of the COD load from water stream 70, with the second vessel acting as a polishing unit for any trace materials passing through the first vessel.
• adsorbent i.e., synthetic adsorbent resin
• dissolved non-volatile organic compounds transfer to and are bound to active sites on the adsorbent surface while treated water stream 84, having COD levels meeting discharge limits, exits hydrocarbon polishing unit 80 via outlet 86.
• the synthetic adsorbent resin used in hydrocarbon polishing unit 80 can be regenerated.
• one vessel remains online treating water stream 70 while the other vessel is regenerated.
• the vessel to be regenerated is taken offline and the saturated synthetic adsorbent resin is contacted with 50-150 psig steam to desorb the bound organics.
• Vapor containing the desorbed organic material exits the vessel being regenerated and is then condensed and recycled to the dehydrator for recovery via outlet 88. It should be appreciated that in some embodiments, all hydrocarbons are recovered in polishing unit 80 thereby eliminating the need to include stripping unit 62, gas flare 72 and bio filter scrubber unit 74.
• Heavy metals and dissolved ion removal subsystem Heavy metals and dissolved ion removal subsystem
• Heavy metals removal subsystem 30 receives water stream 84 exiting hydrocarbon polishing unit 80 contains dissolved heavy metal ions, such as lead, copper, cadmium, mercury, barium and strontium, and other ions such as boron which must be removed to a level suitable for discharge, e.g., discharge in an ocean.
• heavy metals and dissolved ion removal unit 90 comprises two standard ASME pressure vessels filled with ion exchange resin such as AmberliteTM IRA748, AmbersepTM GT74 or AmberliteTM IRA743 (for boron removal), all sold by Dow Chemical Company located in Midland, Michigan.
• ion exchange resins may be used, i.e., ion exchange resins designed for selective removal of trace metal compounds from high salinity solutions.
• the vessels are arranged in series with the first vessel removing the largest portion, and possibly all, of the heavy metals and/or dissolved ions load from water stream 84 with the second vessel acting as a polishing unit for any trace material passing through the first vessel. It should be appreciated that vessels may also be arranged in parallel depending on the needs of the system, spatial constraints, etc.
• Treated water stream 92 is blended with oxidizing agent feed stream 94, which may include oxidizing agents such as chlorine, ozone or hydrogen peroxide, for trace COD removal and 3 ⁇ 4S destruction, after which treated water stream 92 is discharged, e.g., discharged to an ocean via outlet 96.
• treated water stream 92 can be further treated for use in the water recovery stream for enhanced oil recovery (EOR), desalting and hydrofracturing operations as described infra.
• EOR enhanced oil recovery
• the ion exchange resin used in heavy metals and dissolved ion removal unit 90 can be regenerated.
• one vessel remains online treating water stream 84 while the other vessel is being regenerated.
• the vessel to be regenerated is taken offline and saturated ion exchange resin is contacted with concentrated acidic stream 98, e.g., sulfuric or hydrochloric acid, to desorb the heavy metals and other dissolved ions such as boron.
• the ion exchange resin is then contacted with concentrated basic stream 100, e.g., sodium hydroxide, to restore exchange capacity to the ion exchange resin.
• concentrated basic stream 100 e.g., sodium hydroxide
• Regeneration solutions stream 102 exiting the ion exchanged resin bed of heavy metals and dissolved ion removal unit 90 is rich in heavy metals, and is collected for subsequent processing in heavy metals and dissolved ion precipitation unit 104.
• Concentrated basic stream 106 e.g., sodium hydroxide or calcium hydroxide (lime)
• the metal hydroxide precipitate and dissolved ion precipitate is transferred from precipitation unit 104 to filter press 108 using pump 110.
• the metal hydroxide precipitate is filtered from regeneration solutions stream 102 using filter press 108, i.e., a standard filter press well known to those skilled in the art.
• filter press 108 i.e., a standard filter press well known to those skilled in the art.
• Alternative solid/liquid separating devices such as a centrifuge, may also be used.
• Precipitated solids cake 112 are collected for offsite disposal.
• Filtrate stream 114 is recycled to heavy metals and dissolved ion removal unit 90 while final filtered waste water stream 116 may be returned to the dehydrator or discharged.
• water used for EOR operations pressurized water is injected into an oil reservoir to increase reservoir pressure and oil output.
• Water used for this purpose must have low concentrations of sulfate, salts contributing to hardness, metals, boron, TDS and oxygen which otherwise would degrade the oil or yield high concentration of H2S, react with down hole chemistry, or plug the oil recovery collection system in recovered oil or natural gas.
• water reuse subsystem 118 is used to prepare water for subsequent EOR operations, hydrofracturing or other production activities. It should be appreciated that "TDS" is intended to include but not be limited to salts that contribute to water hardness.
• water stream 92 exiting heavy metals and dissolved ion removal unit 90 flows to sulfate and hardness removal membrane unit 120.
• Sulfate and hardness removal membrane unit 120 comprises an array of pressure rated housings filled with spiral wound nanofiltration membrane modules, the number and arrangement of which are dictated by the flowrate of water stream 92 needed to yield a permeate water flowrate of 10-15 gallons/minute/square foot of membrane.
• the membrane elements are Filmtec SR90 sold by Dow Chemical Company located in Midland, Michigan. Water stream 92 is pressurized to 100- 300 psi prior to entering the membrane array of sulfate and hardness removal membrane unit 120 using pump 122.
• Water and some dissolved ionic species namely sodium and chloride ions, pass through the membrane and are collected as permeate water stream 124 amounting to 75-85% volume of water stream 92 entering unit 120.
• the remaining water and higher molecular weight ions e.g., divalents such as sulfate and hardness, are rejected by the membrane array and are discharged to the ocean via outlet 126.
• low TDS water is required for various operations, e.g., EOR, desalting and/or hydrofracturing.
• low TDS water is produced using high pressure, high rejection reverse osmosis membranes.
• permeate water stream 124 flows to TDS removal unit 128.
• TDS removal unit 128 comprises high pressure, high rejection reverse osmosis membrane elements, e.g., FilmtecTM SW30 sold by Dow Chemical located in Midland, Michigan.
• Permeate water stream 124 is pressurized to 700-1500 psi prior to entering the membrane array by a high pressure pump integral to or incorporated within TDS removal unit 128.
• the membrane rejects low weight ionic compounds like sodium and chloride.
• Water stream 129 i.e., water collected from permeate water stream 124, amounts to 30-70% volume of the feed water entering TDS removal unit 128.
• the high pressure, i.e., energy, of waste stream 130 can be recovered using an energy recovery device and returned to the feed stream through reduction of power to the main feed pump.
• Suitable energy recovery units include but are not limited to work exchangers and turbines, e.g., DWEERTM and Calder ERT sold by Flowserve located in Irving, Texas.
• Oxygen removal unit 132 comprises an array of pressure rated housings filled with gas permeable hollow fibers or spiral wound, the number and arrangement of which are dictated by the flowrate of water stream 129 needed to maintain pressure loss at less than 25 psi and to reduce oxygen concentration from saturation to less than 50-100 PPB.
• the membrane elements are Liqui-Cel membrane contactors as sold by Membrana located in Wuppertal, Germany, or alternatively, may be MDS-32502 as sold by Membrane Development Specialist located in Solana, California. It has been found that the spiral wound configuration of MDS-32502 is easily cleaned.
• a booster pump integral to or incorporated within oxygen removal unit 132 boosts water stream 129 to 50- 150 psi prior to entering the membrane array.
• Water and dissolved gases, namely oxygen, flow through the shell side of the contactor.
• a liquid ring vacuum pump pulls a 50 tor vacuum on the tube side to drive gas transfer from the liquid to the gas phase across the membrane.
• nitrogen gas stream 134 from a pressure or thermal swing nitrogen generator flows through the hollow fibers to lower oxygen partial pressure and further drive oxygen from the liquid phase to the gas phase. Sweep gas stream 136 is discharged to atmosphere 138 via vacuum pump 140.
• Deoxygenated water stream 142 may be further polished with the use of an catalytic reaction in pressurized vessel 144.
• pressurized vessel 144 is filled with a palladium-doped resin.
• Deoxygenated water stream 142 receives pressurized hydrogen stream 146 which is dissolved therein. Subsequently, the water stream passes through the resin bed and exits as deoxygenated water stream 148.
• Suitable resins include Lewatit® K 3433 (a crosslinked polystyrene resin with tertiary amine functional groups) sold by Lenntech bv located in Rotterdam, Netherlands. It should be appreciated that in some embodiments, oxygen may be removed from feed water 129 by using an ion exchange resin.
• Deoxygenated water stream 148 which may be blended with oxygen scavenger stream 150 such as hydrazine to further reduce dissolved oxygen concentration below 5 PPB, is then sent to EOR injection equipment for subsequent use via outlet 152.
• oxygen scavenger stream 150 such as hydrazine
• water stream 26 exiting water cleaning system 10 flows to sulfate and hardness removal membrane unit 120.
• Water stream 26 may be ocean water, a fresh water source and/or a pre-treated produced water.
• the structure and function of sulfate and hardness removal membrane unit 120 is described above.
• Water stream 26 is pressurized to 100-300 psi prior to entering the membrane array of sulfate and hardness removal membrane unit 120 using pump 122.
• Water and some dissolved ionic species namely sodium and chloride ions, pass through the membrane and are collected as permeate water stream 124 amounting to 75-85% volume of water stream 26 entering unit 120.
• the remaining water and higher molecular weight ions e.g., divalents such as sulfate and hardness, are rejected by the membrane array and are discharged to the ocean via outlet 126.
• water stream 124 passes directly to oxygen removal unit 132 (as shown by dashed line 154).
• low TDS water is required for various operations, e.g., EOR, desalting and/or hydrofracturing. As described above, low TDS water is produced using high pressure, high rejection reverse osmosis membranes.
• permeate water stream 124 flows to TDS removal unit 128. The structure and operation of TDS removal unit 128 is described above.
• Water stream 129 i.e., water collected from permeate water stream 124, amounts to 30-70% volume of the feed water entering TDS removal unit 128.
• waste stream 130 The remaining water and lower molecular weight ions such as sodium, i.e., waste stream 130, the material rejected by the membranes, are discharged to the ocean or other suitable receiving body via outlet 131.
• the high pressure, i.e., energy, of waste stream 130 can be recovered using an energy recovery device and returned to the feed stream through reduction of power to the main feed pump.
• Suitable energy recovery units include but are not limited to work exchangers and turbines, e.g., DWEERTM and Calder ERT sold by Flowserve located in Irving, Texas.
• the various embodiments comprise single and double stage reverse osmosis systems.
• permeate water stream 124 or 129 flows to oxygen removal unit 132.
• oxygen removal unit 132 The structure and operation of oxygen removal unit 132 is described above.
• Deoxygenated water stream 142 may pass directly out of the system via outlet
• Deoxygenated water stream 148 may pass directly out of the system via outlet
• oxygen removal system may comprise a single or double stage removal system and may further include incorporation of a chemical oxygen scavenger.
• some embodiments may pass the water stream exiting pump 122 directly to oxygen removal unit 132, as shown by dashed line 158, thereby bypassing both sulfate and hardness removal membrane unit 120 and TDS removal unit 128.
• permeate water stream 129 may pass directly to outlet 152 for subsequent use, as shown by dashed line 160, thereby bypassing oxygen removal unit 132 and pressurized vessel 144.
• removal of boron is required.
• Hardness removal membrane systems do not remove boron as it is a monovalent ion (only at higher pH) so a separate boron removal step is required following sulfate and hardness removal membrane unit 120 or following TDS removal unit 128.
• the resin When the resin is saturated with boron it is regenerated using a multiple step process of feeding specific dosages of sulfuric acid and caustic soda and then returned removal unit 162 to service.
• the boron resin is held in a least one pressure or gravity vessel in series with sulfate and hardness removal membrane unit 120 or following TDS removal unit 128, as described above. It should be appreciated that the nature and operation of boron removal unit 162 is substantially similar to the nature and operation of heavy metals and dissolved ion removal unit 90 described supra.
• brine waste stream 131 from TDS removal unit 128 is typically discharge to a surface body of water or deep well injected.
• waste stream 131 can be further concentrated by high pressure sea water reverse osmosis membranes running at pressures up to 1,000-1,500 psi. At these pressures, a reverse osmosis concentrator can produce sodium chloride brines is the range of 8-10%.
• a traditional chloralkali process also known as chlor-alkali and chlor alkali, is an industrial process for the electrolysis of sodium chloride solution, i.e., brine. This process requires concentrations of sodium chloride of approximately 300 grams/liter for efficient process performance.
• the brine solution from the reverse osmosis concentrator must be concentrated in an evaporation process where additional water is evaporated from the brine to concentrate it to approximately 300 g/L.
• a typical piece of equipment to accomplish this step is an evaporator/brine concentrator such as those sold by General Electric. With the brine conditioned and concentrated, it can be fed to a standard pretreatment for a known chloralkali process.
• the present invention provides: hydrocarbon recovery; compact layout; light weight overall structure; minimum chemical use; and, minimum waste generation.
• Unique aspects of the present invention include but are not limited to: use of a resin for oil removal in conjunction with a membrane; use of small foot print filters staged around the resin unit; an air striper with bio filter for volatile organic compounds and I3 ⁇ 4S removal; an air striper with COD resin trap; a heavy metals removal unit in place of conventional precipitation; blending with a sea, fresh or treated water waste stream; water conditioned for use in hydrofracturing, desalting and EOR having high or low TDS; use of degas ification membranes; and, degasification membranes in combination with resin degasification.

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