Patent Application
20140332455
The present invention relates to the removal and recovery of oil, and/or the removal and recovery of contaminants, from aqueous solutions. More specifically, the present invention relates to a system and a method for removing bacteria and recovering oil from oil and gas wastewater, produced water, and other aqueous solutions utilizing photo electro catalytic oxidation.
Photoelectrocatalytic oxidation, or “PECO,” is a process which may be used to treat one or more aqueous solutions to reduce the amount of one or more contaminants within the aqueous solutions. Aqueous solutions include, but are not limited to, hydraulic fracturing fluid, hydraulic fracturing backflow water, produced water, and other contaminated water.
As an example, in the oil and gas industry, water may be used during the process of extracting and/or refining oil or gas. During the extraction or refinement process, the water may become contaminated (e.g. become oil and gas wastewater). Contaminants may include bacteria and/or quantities of the oil and/or gas being extracted.
There are certain advantages for removing the oil and/or gas from the contaminated water. For example, there are certain environmental benefits for removing oil and/or gas from contaminated water. Water which has the oil and/or gas removed or reduced to acceptable levels may subsequently be discharged to the environment. In addition, or as an alternative, the water may be reused during the oil and/or gas extraction process.
As another example, there are certain economic benefits for removing oil and/or gas from contaminated water. Oil and/or gas reclaimed from water may be sold, offsetting certain costs associated with the treatment of contaminated water. Depending upon the quantity of reclaimed oil and/or gas, the sales may lead to additional profits.
While certain equipment is known for the treatment of water contaminated with oil and/or gas, such equipment has certain limitations. For example, known equipment is limited in its ability to quickly and/or effectively separate oil from contaminated water. Known equipment typically relies upon the difference in specific gravity between oil/gas and water to physically separate oil/gas from contaminated water. However, these “separators” require a certain amount of retention time to allow the oil/gas to physically separate from the contaminated water. To increase the retention time for a given contaminated water throughput or concentration of contaminants in contaminated water, the size of the separator vessel needs to be increased, or the liquid depth in the separator vessel needs to be increased. In addition, in applications where contaminated water has a changing concentration of oil/gas contaminants, throughput may have to be adjusted to provide sufficient retention time. In some cases, throughput may have to be substantially reduced to provide sufficient retention time. Accordingly, once a separator vessel is installed, it has certain operational and throughput limitations based upon the size and depth of the equipment, limiting the separator's ability to quickly and effectively treat contaminated water. Further, in certain contaminated water streams, emulsified oil/gas can become “trapped” in the water stream. Separators alone are typically unable to treat these contaminated water streams, as the emulsion is “stable” or, stated otherwise, will not substantially separate over time. An alternative to treat stable emulsions of oil/gas and water is to add certain chemicals to destabilize the emulsion. However, these chemicals can be hazardous and require additional treatment steps for removal from the contaminated water.
Accordingly, there is a need for an improved system and method for removing and recovering oil/gas from water which will allow for an increase in oil/gas recovery without substantially increasing water treatment expenses.
The present invention provides a system and method for the removal and recovery of oil and/or gas from contaminated aqueous solutions, including contaminated water. The system and method implements a PECO device to destabilize emulsions of oil and/or gas and contaminated water to assist with the recovery of oil and/or gas from the contaminated water. The system and method also provides for improved emulsion destabilization without requiring the addition of chemicals not present in the emulsion. This enhances oil and/or gas recovery from the contaminated water without requiring additional treatment steps to address the added chemicals.
A system for recovering oil from an oil and/or gas wastewater or other contaminated water stream is provided. In various embodiments, the system includes a multi-stage system having an electro-precipitation and/or electrocoagulation stage and a PECO stage. In various embodiments, the system includes a multi-stage system for removing and recovering oil from contaminated water having a primary oil recovery stage in fluid connection with a secondary oil recovery stage, wherein a PECO assembly is provided in the primary oil recovery stage to facilitate destabilization of emulsions of oil and contaminated water.
Methods for recovering oil from a contaminated water stream are also provided. One method includes the steps of introducing contaminated water to an electroprecipitator or electrocoagulator, separating and recovering oil from the contaminated water (e.g., using a filter), and introducing the remaining contaminated water to a photoelectrocatalytic oxidation assembly, treating the contaminated water in the photoelectrocatalytic oxidation assembly.
Another method for recovering oil from a contaminated water stream is also provided. This method includes the steps of introducing contaminated water to a separator, separating and recovering oil from the contaminated water at the separator, introducing contaminated water from the separator to a photoelectrocatalytic oxidation assembly, treating the contaminated water in the photoelectrocatalytic oxidation assembly to destabilize emulsifications in the contaminated water, introducing contaminated water from the photoelectrocatalytic oxidation assembly to a flotation unit, further separating oil from the contaminated water in the flotation unit, recovering oil from the flotation unit, and recovering water from the flotation unit.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described below in detail. It should be understood, however, that the description of specific embodiments is not intended to limit the disclosure from covering all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure.
The invention illustrated in the Figures and disclosed herein is generally directed to a system for removing and recovering oil from contaminated water and/or removing or reducing the amount of bacteria and/or other contaminants present in the contaminated water, and associated method of operation. In various embodiments, the system incorporates a PECO system to facilitate enhancement of oil recovery and/or removal of bacteria from the contaminated water. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. Although any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of the present disclosure, example methods and materials are described below.
It should be appreciated that “contaminated water” or “wastewater” is used for purposes of illustration. The term “contaminated water” or “wastewater” may include any contaminated aqueous solution where the contaminant is emulsified or otherwise include within the aqueous solution.
In addition, it should be appreciated that “oil” is used for purposes of illustration of an example of a contaminant provided within a contaminated aqueous solution. While the specification refers to “oil” for ease of understanding, “oil” should be understood to mean any contaminant or contaminants which may be emulsified or otherwise included with wastewater. Examples of other contaminants may include, without limitation, crude oil, natural gas, hydrocarbons, or any other material which is emulsified or otherwise included in wastewater.
Referring now to the Figures,
As illustrated in
In operation, in various embodiments, contaminated water is provided or introduced to primary oil recovery stage 15. The contaminated water may be provided to primary oil recovery stage 15 through a number of ways. For example, contaminated water may be removed from the source of contamination, such as a mine or drilling site, by a transportation vehicle, such as a tanker truck or haul truck. The contaminated water may then be shipped to a location where the system for removing and recovering oil from contaminated water is located. As another example, contaminated water may be directly piped from a source of contamination to a location where the system for removing and recovering oil from contaminated water is located. It should be appreciated that any suitable apparatus, method, or system for supplying contaminated water to the system for removing and recovering oil from contaminated water may be implemented. In addition, the contaminated water may be stored in a tank, reservoir, or other suitable holding apparatus prior to introduction to the system for removing and recovering oil from contaminated water.
Once introduced to the primary oil recovery stage, in various embodiments, the contaminated water is treated. More specifically, the treatment of the contaminated water includes separating oil from the contaminated water. Oil that is separated from contaminated water may then be recovered. In various embodiments, the recovered oil is removed from the primary stage and collected for later use or sale. In addition, a portion of water may be substantially cleaned, treated, or separated from the contaminants in the primary stage such that it may be recovered (e.g., for disposal or re-use).
Referring to
Following treatment by PECO unit, device, or system 17, the contaminated water is provided or introduced into a dissolved air floatation tank or unit 18. It should be appreciated in one or more examples of embodiments that a dissolved gas flotation (“DGF”) may be used in place of dissolved air flotation tank 18. In addition, in one or more examples of embodiments, pressurized air may be directly introduced into dissolved air floatation tank 18 and released at a lower pressure, including atmospheric, to form air bubbles.
In various embodiments, PECO device 17 facilitates separation of oil from contaminated water through DAF (or DGF), as the treatment process in PECO unit 17 destabilizes the emulsion of oil and water in the contaminated water, allowing the bubbles to adhere to the oil and separate it from the water.
Recovered water is removed from primary oil recovery stage 15 and collected for disposal or later reuse. In various embodiments, the remaining contaminated water, which may contain additional oil, water, and/or contaminants, is collected, removed from primary oil recovery stage 15, and introduced to secondary oil recovery stage 20 for additional treatment and oil extraction.
More specifically, in various embodiments, the oil and contaminated water collected from the surface of dissolved air floatation tank 18 (or a dissolved gas floatation tank) travels to, or is provided or introduced to, secondary oil recovery stage 20. In various embodiments, secondary oil recovery stage 20 includes a heater treater 22. In one or more examples of embodiments, a vertical heater treater is utilized. However, a horizontal heater treater may also be utilized.
At secondary oil recovery stage 20, contaminated water is further processed to remove oil from a contaminated water emulsion. Any removed oil at second oil recovery stage 20 is recovered, removed from secondary oil recovery stage 20, and collected for later use or sale. In addition, a portion of water may be substantially cleaned or separated from the contaminants in secondary oil recovery stage 20 such that it may be recovered. Any recovered water may be removed from secondary oil recovery stage 20 and collected for disposal or later reuse. In various embodiments, the recovered water from the secondary oil recovery stage may be reintroduced into the primary oil recovery stage for further processing and removal of contaminants. Any remaining contaminated water from secondary oil recovery stage 20 may be disposed of, or in the alternative, may be further processed in additional stages or collected and treated at a separate contaminated water clarification process.
Referring now to
In various embodiments, system or treatment train 25 includes two or more of the following stages or components: a first suspended solids filtration system, apparatus, device or stage 30, an electrochemical system, apparatus, device or stage 40, a second suspended solids filtration system, apparatus, device or stage 50, and a PECO system, apparatus, device or stage 60. In various embodiments, the components or stages 30/40/50/60 are coupled (e.g., fluidly coupled), or otherwise utilized in series or a sequence.
In various embodiments, first suspended solids filtration system 30 includes one or more of the following device or system types: bag filter, dissolved air floatation 35, clarifier, and/or gravity weir floatation. Example of bag filter devices or systems that may be utilized include the Duoline, Ecoline, Flowline, Flowline II, Maxiline, Miniline, Moduline, Polyline, Proline, Sideline, and Topline brand bag filter devices or systems available from Eaton Corporation PLC of Dublin, Ireland.
Examples of various dissolved air floatation devices or systems that may be utilized are PCL-Series brand available from FRC Systems International of Cumming, Ga., the Ideal brand dissolved air floatation devices or systems available from World Water Works, Inc. of Oklahoma City, Okla., and MicroAire DAF brand dissolved air floatation devices or systems available from VanAire, Inc. of Gladstone, Mich.
Examples of various clarifier devices or systems that may be utilized include the Envirex brand clarifier available from Met-Chem, Inc. of Cleveland, Ohio, and Siemens Water Technologies of Alpharetta, Ga.
Examples of various gravity weir filtration devices or systems that may be utilized include those available from Dragon Products Ltd. of Beaumont, Tex., and Adler Tank Rentals of South Plainfield, N.J., a division of McGrath RentCorp of Livermore, Calif.
In various embodiments, electrochemical system or stage 40 includes an electroprecipitation device or system 45, and/or an electrocoagulation system or device. An example of an electrochemical device or system that may be utilized is a mobile treatment unit available from Rockwater Energy Solutions of Houston, Tex., utilizing a patented electro-oxidation process powered by Pathocell technology of Neohydro Corp. of Houston, Tex.
Examples of electrocoagulation systems or devices that may be utilized include those (e.g., Waveionics) available from Water Tectonics, Inc. of Everett, Wash., or Universal Systems, Inc. of Baker City, Oreg.
In various embodiments, second suspended solids filtration system, apparatus or stage 50 includes one or more of the following device or system types: bag filter, dissolved air floatation, clarifier, and/or a gravity weir filtration system, apparatus or device. The second suspended solids filtration system, apparatus or stage may or may not be the same as the first suspended solids filtration system, apparatus or stage.
Contaminated water such as produced or flowback water is provided to first suspended solids filtration system, apparatus or stage 30. The contaminated water may be provided through a number of ways. For example, contaminated water may be removed from the source of contamination, such as a mine or drilling site, by a transportation vehicle, such as a tanker truck or haul truck. The contaminated water may then be shipped to a location where the system for removing and recovering oil from contaminated water is located. As another example, contaminated water may be directly piped from a source of contamination to a location where the system for removing and recovering oil from contaminated water is located. It should be appreciated that any suitable apparatus, method, or system for supplying contaminated water to the system for removing and recovering oil from contaminated water may be implemented. In addition, the contaminated water may be stored in a tank, reservoir, or other suitable holding apparatus prior to introduction to the system for removing and recovering oil from contaminated water. In various embodiments, before or about the time the contaminated water is introduced to first suspended solids filtration system, apparatus or device 30, the contaminated water is dosed with coagulant (e.g., ferric chloride or aluminum sulfate) to help flocculate suspended solids. However, the dosing is optional.
Once introduced to first suspended solids filtration system, apparatus or stage 30, the contaminated water is treated. In various embodiments, the treatment involves or includes separating oil from the contaminated water. Oil that is separated from contaminated water may be recovered. In various embodiments, the recovered oil is removed from first suspended solids filtration system, apparatus or stage 30 and collected (e.g., for later use or sale). In addition, at least a portion of water may be at least partially cleaned or separated from the contaminants in first suspended solids filtration system, apparatus or stage 30 such that it may be recovered. The recovered water may be removed from first suspended solids filtration system, apparatus or stage 30 and collected for disposal or later reuse.
In various embodiments, any remaining contaminated water, which may contain additional oil, water, and/or contaminants, is removed from first suspended solids filtration system, apparatus or stage 30 and introduced to electrochemical system, device, or stage 40 which includes an electro-precipitation 45 and/or electro-coagulation system, apparatus, or stage (e.g., for additional or continued treatment and/or oil extraction or recovery).
At electrochemical system, apparatus, or stage 40, remaining contaminated water is further processed to help remove oil, bacteria and other suspended solids (e.g., from the contaminated water emulsion). In various embodiments, electro-precipitation system, apparatus, or stage 45 is utilized to help further separate oil, solids, and/or other solids or contaminants from the emulsion. In various embodiments, emulsified oil is destabilized electrochemically (e.g., by electroprecipitation).
The remaining contaminated water may then be provided to second suspended solids filtration system, apparatus or stage 50. In various embodiments, second suspended solids filtration device 50 includes gravity weir filtration device 55.
Once introduced to second suspended solids filtration system, apparatus or stage 50, the remaining contaminated water is treated. More specifically, treatment in the second suspended solids filtration system, apparatus or stage 50 includes or involves separating oil from the contaminated water. Oil that is separated from contaminated water may be recovered. The recovered oil may be removed from second suspended solids filtration system, apparatus or stage 50 and collected (e.g., for later use or sale). In addition, a portion of water may be at least partially cleaned or separated from the contaminants in second suspended solids filtration system, apparatus or stage 50 such that it may be recovered. The recovered water may be removed from second suspended solids filtration system, apparatus or stage 50 and optionally collected for disposal or later reuse.
Referring to both
In various embodiments, contaminated water from second suspended solids filtration system, apparatus or stage 50 is introduced to PECO system, apparatus, or stage 60. The PECO system, apparatus, or stage enhances oil recovery from the contaminated water, as the PECO process generates oxidants that destabilize emulsified oil, or emulsifications including oil, trapped in the contaminated water.
Referring now to
In various embodiments, PECO apparatus 130 is elevated at one end (e.g., at the end closest to the output) relative to the other. This may encourage collection of gases at the one end and may also help solution to completely, substantially, or optimally fill PECO apparatus 130 during use. Input 110 may be provided relatively lower in elevation or below PECO apparatus 130 and output 120 may be provided relatively higher in elevation or above PECO apparatus 130 to also help completely, substantially, or optimally fill PECO apparatus 130 during use.
Input manifold 140 and output manifold 150 each helps to allow multiple PECO apparatus 130 of PECO system 100 to be configured and/or utilized in parallel. It should be appreciated, however, that the PECO apparatus of the PECO system may also be utilized in series, or alone, in various applications and embodiments. For example, in various embodiments, one or more of the input manifold branches and one or more of the output manifold branches may be coupled to a valve 160 to help regulate and/or control flow through PECO apparatus 130 or PECO system 100 generally.
Multiple PECO systems 100 may be operatively and/or fluidly connected together (e.g., in series). For example, the output of a first PECO system may be fluidly connected to the input of a second PECO system to operatively and fluidly connect the systems in series. In various other embodiments, multiple PECO systems may be operatively or fluidly connected in parallel.
As shown in
In various embodiments, PECO system 100 and/or PECO apparatus 130 includes and/or is a substantially self-contained system and/or apparatus (apart from the input or in-flow and output or out-flow apertures, gas vents, etc.). Each PECO apparatus 130 in various embodiments includes a housing, chamber, or container 170 which is adapted to at least partially receive components (e.g., one or more operative components) of PECO apparatus 130 and/or at least temporarily receive, contain and/or circulate fluid or aqueous solution.
In various embodiments, housing 170 includes at least one generally annular, tubular (e.g., a square or rectangular tube), cylindrical or conical housing member 180 extending between a first opposing end 190 and a second opposing end 200. Housing member 180 of each PECO apparatus 130 may be formed of any suitable materials, or combination of materials, and be of any size or shape suitable for its intended purposes. In one or more examples of embodiments, housing member 180 is a molded, high-durability plastic or polyethylene (e.g., PVC) and/or may be formed to be resistant to one or more contaminants. Housing member 180 may also take alternative shapes, sizes, and configurations. One or more components of housing 170 and/or housing member may also be constructed of metal which may be lined (e.g., with an inert polymer compound such as Teflon or PPS material).
In various embodiments, housing 170 includes a first fitting 190 provided about first opposing end 210 and a second fitting 200 provided about second opposing end 220 of housing member 180. Fittings 190/200 may be formed of any suitable materials, or combination of materials, and be of any size or shape suitable for their intended purposes. In one or more examples of embodiments, fittings 190/200 are made of a high-durability plastic or polyethylene (e.g., PVC) and/or may be formed to be resistant to one or more contaminants. In one or more other examples of embodiments, the fittings are made of metal. Alternative materials and shapes suitable for the purposes of the system and/or apparatus are also acceptable.
In various embodiments, fittings 190/200 are T-fittings defining one or more in-flow apertures and/or out-flow apertures. In various embodiments, the in-flow and out-flow apertures defined by fittings 190/200 are fluidly connected to input 110 and/or input manifold 130, and/or output 120 and/or output manifold 140. The locations of the in-flow and out-flow apertures may vary depending upon the desired results (e.g., the flow of solution through the apparatus, the timing and/or length of time thereof, other system configurations, etc.). For example, the in-flow and out-flow apertures may be provided through the housing member or ends of the PECO apparatus. In addition, the orientation of the in-flow and out-flow apertures (e.g., relative to each other) may be different than or modified from that shown in the Figures.
In various embodiments, one or both fittings 190/200 define a fitting cavity or other feature shaped to fit snugly or tightly to or otherwise receive or be received by one or both opposing ends 210/220. However, one or both of the fittings may be coupled with or to the opposing ends and/or the housing member in other ways (e.g., through a threaded connection or by butting the respective fitting to or near the first and second opposing ends). In various embodiments, a seal (e.g., an O-ring) is provided between one or both of fittings 190/200 and opposing ends 210/220.
Referring now to
In various embodiments, housing cavity 240 is adapted to receive various components of PECO apparatus 130. In various embodiments, at least one reactor assembly 250 is at least partially provided in or received by housing cavity 240. In various embodiments, multiple (e.g., two) reactor assemblies 250 are provided in housing cavity 240. For example, and as shown in
Referring now to
In various embodiments, reactor assembly 250 includes first light source assembly 280 (e.g., a centralized UV light source) with one or more second light source assemblies 300 (e.g., six additional UV light sources) provided (e.g., in a spaced relationship) around first light source assembly 280. In various embodiments, first light source assembly 280 is provided about a longitudinal axis 305 of reactor assembly 250. In various embodiments, one or more second light source assemblies 300 are spaced around longitudinal axis 305. In various embodiments, one or more second light source assemblies 300 are generally spaced symmetrically around longitudinal axis 305. In various embodiments, one or more counterelectrodes 260 or cathodes are provided (e.g., in a spaced relationship) around first light source assembly 280 (e.g., in one or more of the spaces between the second light source assemblies 300). In various embodiments, one or more counterelectrodes or cathodes 260 (e.g., counterelectrode or cathode strips) are provided offset from their mounting hole centerlines. Among other things, this may allow additional counterelectrodes (e.g., an additional counterelectrode for each offset mounting hole) to be added to the reactor assembly as necessary or desired to help balance or otherwise better optimize reactions (e.g., with first and/or second photoelectrodes 270/290.
In various embodiments, reactor assembly 250 includes second photoelectrode 290 provided between first photoelectrode 270 and housing wall 230. In various embodiments, reactor assembly 250 includes a second light source assembly 300 provided between first photoelectrode 270 and second photoelectrode 290. In various embodiments, reactor assembly 250 includes multiple second light source assemblies 300 (e.g., spaced second light source assemblies) provided between first light source assembly 280 and second photoelectrode 290 and/or housing wall 230. In various embodiments, one or more second light source assemblies 300 are spaced in a radial array between first photoelectrode 270 and second photoelectrode 290.
One or more of the counterelectrodes may be provided in a variety of positions in the reactor assembly, and/or the PECO apparatus. For example, in various embodiments, at least one counterelectrode 260 is provided between multiple first and/or second light source assemblies 280/300. As another example, at least one counterelectrode 260 may be provided in a space between housing wall 230 and the one or more light source assemblies. In one or more examples of embodiments, one or more counterelectrodes 260 are provided in a spaced relationship radially around first photoelectrode 270. In various embodiments, one or more counterelectrodes 260 are provided between first photoelectrode 270 and second photoelectrode 290. In various embodiments, the one or more counterelectrodes 260 are arranged between the first photoelectrode 270 and second photoelectrode 290 and second light source assemblies 300 (e.g., on a line or ring concentric to the longitudinal axis of first light source assembly and/or housing member 180).
It should be appreciated that, while seven light source assemblies 280/300 are shown in the
In various embodiments, reactor apparatus 250 includes first light source assembly 280 centrally located within a space from housing wall or walls 230 and one or more second light source assemblies 300 between first light source assembly 280 and housing wall or walls 230. For example, reactor assembly 250 may include first light source assembly 280 at or near the longitudinal axis of housing cavity 240 at least partially surrounded, encircled, and/or ringed by multiple (e.g., six) second light source assemblies 300, each of which is provided within housing cavity 240.
It should be noted, however, that the light source assemblies may be provided with the housing cavity in any variety of ways and locations, and it is not necessary that the light source assemblies be provided concentrically within and/or centrally spaced from the wall or walls forming or defining the housing cavity. Rather, the light source assemblies may be provided in any variety of positions and/or configurations without departing from the spirit and scope of this disclosure. In various embodiments, the reactor assembly also includes a means for cleaning or unfouling the light sleeve or tube of the one or more light source assemblies.
In various embodiments, one or more first and second photoelectrodes 270/290 are provided within housing cavity 240. In various embodiments, first photoelectrode 270 is provided at least substantially around first light source assembly located on or about the longitudinal or central axis of the housing cavity 240. In various embodiments, second photoelectrode 290 may be wrapped, wound, or otherwise provided at least substantially around first photoelectrode 270 and one or more light source assemblies 280/300, and/or housing wall 230. In various embodiments, first photoelectrode 270 is provided between a centrally located first light source assembly and one or more second light source assemblies 300. In various embodiments, second photoelectrode 290 is provided between all light source assemblies of the reactor assembly and the housing wall 230.
In various embodiments, first photoelectrode 270 (e.g., anode) may be wrapped, wound, or otherwise provided around and/or between first light source assembly 280 concentric within and/or spaced apart from the housing wall 230 and one or more second photoelectrodes 290. In various embodiments, second photoelectrode 290 may be wrapped, wound, or otherwise provided around and/or between first photoelectrode 270 and housing wall 230. In examples of embodiments, one or more second light source assemblies 300 are provided between first photoelectrode 270 and second photoelectrode 290.
In one or more examples of embodiments, first photoelectrode 270 and second photoelectrode 290 (e.g., a foil photoelectrode) are wrapped, wound, or otherwise provided within housing cavity 240 such that a majority or substantial portion of UV light or radiation (e.g., from the first and second light source assemblies) with housing cavity 240 is directed at or otherwise exposed to first and second photoelectrodes 270/290.
It should be appreciated that any number of photoelectrodes and light source assembly configurations may be utilized within a scope of this disclosure. In various embodiments, the photoelectrodes are provided (e.g., around the light source assemblies) to optimize the distance, separation or spacing between the photoelectrodes and the light source assemblies. In various embodiments, one or more photoelectrodes may be wrapped, wound, or otherwise provided around the surface of a light tube or sleeve of each light source assembly, multiple light tubes or sleeves, or one light tube or sleeve. The photoelectrodes may be provided closely or tightly around or against each light source assembly. In various embodiments, a photoelectrode may be coupled (e.g., removably coupled) to a light source assembly.
In various embodiments, and as shown in
Referring now to
Referring now to
While the figures show a variety of light source assembly configurations including a seven light source assembly configuration, a six light source assembly configuration, and a sixteen light tube or sleeve configuration, it should be appreciated that any number of light tubes or sleeves in any variety of configurations may be utilized or otherwise provided.
Referring again to
In various embodiments, one or more counterelectrode and/or photoelectrode apertures are defined by bulkhead member 320. In various embodiments, the one or more counterelectrode and photoelectrode apertures defined by bulkhead member 320 are provided between and/or near two or more light source apertures 330/340 to allow a bias or potential to be applied to photoelectrodes 270/290 and counterelectrodes 260 of reactor assembly 250. It should be appreciated that, while seven light source apertures 330/340 are shown, any number of the light source apertures may be defined by the bulkhead member. It should also be appreciated that, while six counterelectrode apertures and two photoelectrode apertures are defined by bulkhead member 320 are shown in the Figures, any number of the photoelectrode apertures and the counterelectrode apertures may be defined by the bulkhead member.
In various embodiments, terminals, terminal configurations and/or leads are electrically coupled to the photoelectrodes. The leads are adapted to receive an applied voltage bias, potential and/or current provided by a power source connected or otherwise coupled (e.g., electrically connected coupled) to the leads. The leads are formed of a conductive material, such as a conductive metal. One or more of the leads may define or be provided with an aperture for ease of connection or coupling of the lead to a wire, electrical cable or the like.
While not shown, the photoelectrode(s) and counterelectrode(s) may be separated by a separator. Each separator may be used or otherwise provided to prevent shorting. In one or more examples of embodiments, each photoelectrode (e.g., anode) and counterelectrode (e.g., cathode) are separated by plastic or plastic mesh separator, although alternative separators (e.g., other dielectric material(s) or other separators accomplishing or tending to accomplish the same or similar purposes) may be acceptable for use with the device and system described herein.
In various embodiments, first and second photoelectrodes 270/290 include a conductive support member and a film member. In one or more examples of embodiments, the conductive support member is constructed from metal (e.g., titanium or Ti). In various embodiments, the film member is nanoporous and includes a thin layer (e.g., 200-500 nm) of titanium dioxide (TiO2) (e.g., a TiO2 coating) that is provided and/or adapted to function as a photocatalyst. In various examples of embodiments, the film member has an average thickness in the range of 1-2000 nanometers. In one or more examples of embodiments, the film member has an average thickness in the range of 5 to 500 nanometers.
In various embodiments, the film member is provided on (e.g., coated on or adhered to) the conductive support member. In various embodiments, the film member has a median pore diameter in the range of 0.1-500 nanometers and is constructed from TiO2 nanoparticles. In one or more examples of embodiments, the median pore diameter of the film member is in the range of 0.3-25 nanometers. In other examples of embodiments, the median pore diameter of the film member is in the range of 0.3-10 nanometers.
In various examples of embodiments, the film member is constructed from a stable, dispersed suspension comprising TiO2 nanoparticles having a median primary particle diameter in the range of 1-50 nanometers. The nanoporous film may also be deposited by other methods, such as plasma, chemical vapor deposition or electrochemical oxidation. In one or more examples of embodiments, the TiO2 nanoparticles have a median primary particle diameter in the range of 0.3-5 nanometers.
In various embodiments, the film member is constructed from a stable, dispersed suspension including a doping agent. Examples of suitable doping agents include, but are not limited to, Pt, Ni, Au, V, Sc, Y, Nb, Ta, Fe, Mn, W, Co, Ru, Rh, P, N and/or carbon (including carbon nanotubes, fullerenes, graphene, etc.).
In various examples of embodiments, the nanoporous film member is constructed by applying a stable, dispersed suspension having TiO2 nanoparticles suspended therein. In various embodiments, the TiO2 nanoparticles are sintered at a temperature in the range of 300 deg C. to 1000 deg C. for 0.5 to 24 hours. Example photoelectrodes may be prepared by coating Ti metal foil. Titanium foil is stable and may also be used to make the first and second photoelectrodes. One example of suitable Ti metal foil includes 15 cm×15 cm×0.050 mm thickness and 99.6+% (by weight) pure Ti metal foil commercially available from Goodfellow Corp. (Oakdale, Pa.) with a titania-based metal oxide. In various embodiments, the Ti metal foil is cleaned with a detergent solution, rinsed with deionized water, rinsed with acetone, and/or heat-treated at 350 deg C. for 4 hours providing an annealed Ti foil. Annealing may also be conducted at higher temperatures such as 500 deg C.
Following cleaning and/or pretreatment, in various embodiments, the metal foil may be dip-coated. For example, the metal foil may be dip-coated three to five times with an aqueous suspension of titania at a withdrawal rate of ˜3.0 mm/sec. After each application of coating, in various embodiments, the coated foil is air dried for about 10-15 min and then heated in an oven at 70 deg C. to 100 deg C. for about 45 min. After applying a final coating, in various embodiments, the coated foil is sintered at 300-600 deg C. (e.g., 300 deg C., 400 deg C. or 500 deg C.) for 4 hours at a 3 deg C./min ramp rate. The Ti foil may be dipped into suspensions of titania synthesized using methods disclosed in U.S. patent application Ser. Nos. 11/932,741 and 11/932,519, each of which is incorporated herein by reference in its entirety. In various embodiments, the optimized withdrawal speed is around 21.5 cm min−1.
In addition, in one or more examples of embodiments, the stable, dispersed suspension is made by reacting titanium isopropoxide and nitric acid in the presence of ultrapure water or water purified by reverse osmosis, ion exchange, and one or more carbon columns. In various embodiments, the conductive support member is annealed titanium foil. Other conductive supports may be employed, such as conductive carbon or glass. In various other embodiments, the first and second photoelectrode may be constructed from an anatase polymorph of Ti or a rutile polymorph of Ti. In one or more examples of embodiments, the rutile polymorph of Ti is constructed by heating an anatase polymorph of Ti at a temperature in the range of 300 deg C. to 1000 deg C. for a sufficient time. In one or more examples of embodiments, the anatase polymorph of Ti is heated at 500 deg C. to 600 deg C. to produce the rutile polymorph of Ti.
In various embodiments, after the titanium support is provided with a layer or film of TiO2, the composite electrode is air-heated at a high temperature, giving the nanoporous TiO2 film a crystalline structure due to thermal oxidation. It is believed that the instant titania, when heated at 500 deg C., converts to a crystalline rutile polymorph structure. It is further believed that the instant TiO2 heated at 300 deg C. converts to a crystalline anatase polymorph structure. In some PECO applications, rutile TiO2 has substantially higher catalytic activity than the anatase TiO2. Rutile TiO2 may also have substantially higher catalytic activity with respect to certain contaminant such as ammonia.
The first and/or second photoelectrodes may be modified (e.g., to improve performance). In various embodiments, the photoelectrodes (e.g., Ti foil) are modified to increase the surface area of the photoelectrodes exposed to light such as UV light. For example, the photoelectrodes may be corrugated. As another example, the photoelectrodes may be wavy. The photoelectrodes may include various other features or microfeatures to help optimize the surface exposed to UV light and/or help cause turbulence in fluid or solution about the photoelectrode.
In various embodiments, photoelectrode modifications include corrugating or otherwise modifying the photoelectrodes, conductive support member or foil to produce a wave-like pattern (e.g., regular wave-like pattern) on the foil surface. In various embodiments, the height of a corrugation “wave” is from about 1-5 mm. For example, in various embodiments, corrugating the foil twice at right angles to each other produces a cross-hatched pattern on the foil surface.
In various embodiments, the photoelectrode modifications include holes or perforations made, defined by or provided in photoelectrodes, conductive support member, or foil. In various embodiments, the holes or perforations are made or provided at regular intervals (e.g., 0.5 to 3 cm spacing between the holes).
Modifications of the photoelectrodes may also include various microfeatures and/or microstructures. Accordingly to various embodiments, the modifications of the photoelectrodes, conductive support members or foils may also include various microfeatures and/or microstructures that increase the relative surface area of the photoelectrodes and/or increase or promote turbulence about the photoelectrodes. For example, according to various embodiments, such microfeatures and/or microstructures include those that are disclosed in U.S. Patent Publication Nos. 20100319183 and 20110089604, each of which is incorporated herein by reference in its entirety, or such microfeatures and/or microstructures that are provided commercially from Hoowaki, LLC (Pendleton, S.C.). In various embodiments, the microfeatures may include microholes. In various embodiments, modifications of the photoelectrodes include the formation of nanotubes (e.g., TiO2 nanotubes) on the photoelectrodes, conductive support members and/or foils such as, for example, those that are disclosed in U.S. Patent Publication No. 20100269894, which is incorporated herein by reference in its entirety.
As a result of the holes, the positioning, the corrugation, and other modifications, etc., the photoelectrodes may help create turbulence in fluid flowing in and/or through the PECO apparatus. Additionally, one or more holes may allow oxidants generated or produced on or near a surface of the photoelectrodes to more rapidly and effectively make their way into or otherwise reach or react with the fluid (e.g., aqueous solution) and/or contaminants therein.
In one or more examples of embodiments, the photoelectrodes are in the form of a mesh (e.g., a woven mesh, such as a 40×40 twill weave mesh or 60×60 Dutch weave mesh, or a non-woven mesh).
In various embodiments, counterelectrode (e.g., cathode) 260 is in the form of a rod such as a rod with an L-shaped cross-section. However, the counterelectrode may be in the form of a wire, foil, plate, cylinder, or in another suitable shape or form. In various embodiments, the counterelectrode may be corrugated and/or have other features to help cause or promote turbulence in fluid or solution in the cavity.
In one or more examples of embodiments, the counterelectrode or cathode is constructed from or includes Al, Pt, Ti, Ni, Au, stainless steel, carbon and/or another conductive metal.
Referring now to
In various embodiments, spacer member 310 includes one or more dividers 350 extending between a peripheral concentric portion 325 and an axial concentric portion 335. Divider 350 is adapted to help direct, redirect, mix, stir or otherwise influence solution as it passes through the spacer. Such mixing or flow may be advantageous in many ways. For example, such mixing or flow may help to mix oxidants generated by the device into the solution. As another example, such mixing or flow may increase the residence time of the solution in the cavity of the device for even a solution of moderate velocity. It should also be noted that any number of spacers 310 may be utilized anywhere within the cavity. In various embodiments, spacer 310 allows for flanges to be provided along the length of each counterelectrode or cathode on either or both edges of the counterelectrode or cathode to help create a counterelectrode surface that is substantially parallel or otherwise aligned with a surface of the first and/or second photoelectrode or anode. In various embodiments, the spacer has an optimal or minimal cross-sectional area to optimize or minimize any restrictions on flow through the device or apparatus.
Referring now to
In various embodiments, light tube or sleeve 370 includes at least one wall or sidewall 380 that helps define a tube cavity 390 that at least partially houses and/or is at least partially adapted to receive one or more light sources 360 (e.g., an ultraviolet (UV) light source, light, or lamp). For example, a UV-light bulb or bulbs may be provided or inserted into the tube cavity. In various embodiments, light source 360 is provided and/or extends a distance into tube cavity 390, such that the light (e.g., UV) provided thereby may be exposed to one or more of the first and second photoelectrodes (and/or one or more photoelectrodes may be exposed to UV), illuminating or radiating to some or all of a surface thereof according to the various embodiments described herein. In various embodiments, each light tube or sleeve 370 is coupled to an adapter or end cap 400.
In various embodiments, end cap or adapter 400 is provided around and coupled (e.g., glued) to an end of light tube or sleeve 370. In various embodiments, adapter or end cap 400 defines an aperture through which sensors and wiring 410 (e.g., wiring for powering a UV light source) and other connections may be provided. In various embodiments, at least a portion of adapter 400 is threaded. Any threads along with various seals (e.g., O-rings) help prevent fluid from leaking while also allowing each light source assembly to be removable from the reactor assembly (e.g., for repair, replacement, etc.).
In various embodiments, the end cap or adapter further includes a gland cap. In various embodiments, wires are potted or otherwise sealed to the gland cap or adapter. In various embodiments, the gland cap provides a fluid seal in the event of a break or leak of the light tube or sleeve. In various embodiments, the gland cap is screwed into threads provided in an aperture defined by the end cap or adapter. In various embodiments, an O-ring is provided between the end cap and the gland cap to provide a seal to prevent fluid from leaking outside of the cavity. In various embodiments, an additional seal such as a epoxy bead may be provided between the end cap and the light tube or sleeve.
The light source may be provided or inserted into a socket provided in the adapter and may be secured in position. Each light source is further coupled or connected (e.g., electrically connected via wiring 410 or a socket), or adapted to be coupled or connected, to a source of power. In various embodiments, the light source or UV bulb is coupled or connected (e.g., electrically) via one or more cables or wires to one or more ballasts and/or power sources. In various embodiments, light source 360 extends into at least a majority of each light tube or sleeve 370. However, in various embodiments, the light source may extend only partially or not at all into the light tube or sleeve.
In various embodiments, light source 360 is a high irradiance UV light bulb. In one or more further examples of embodiments, light source 360 is a germicidal UV bulb with a light emission in the range of 400 nanometers or less, and more preferably ranging from 250 nanometers to 400 nanometers.
In various embodiments, the ultraviolet light of light source 360 has a wavelength in the range of from about 185 to 380 nm. In one or more examples of embodiments, light source 360 is a low pressure mercury vapor lamp adapted to emit UV germicidal irradiation at 254 nm wavelength. In one or more alternative examples of embodiments, a UV bulb with a wavelength of 185 nm may be effectively used as the light source. Various UV light sources, such as those with germicidal UVC wavelengths (peak at 254 nm) and black-light UVA wavelengths (UVA range of 300-400 nm), may also be utilized. In one or more examples of embodiments, an optimal light wavelength (e.g., for promoting oxidation) is 305 nm. However, various near-UV wavelengths are also effective. Both types of lamps may emit radiation at wavelengths that activate photoelectrocatalysis. The germicidal UV and black light lamps are widely available and may be used in commercial applications of the instant PECO device.
In one or more additional examples of embodiments, light source 360 is adapted to emit an irradiation intensity in the range of 1-500 mW/cm2. The irradiation intensity may vary considerably depending on the type of light source used. Higher intensities may improve the performance of the device (e.g., PECO device). However, the intensity may be so high that the system is UV-saturated or swamped and little or no further benefit is obtained. That optimum irradiation value or intensity may depend, at least in part, upon the distance between the lamp and one or more photoelectrodes.
The intensity (i.e., irradiance) of UV light at the photoelectrode may be measured using a photometer available from International Light Technologies Inc. (Peabody, Mass.), e.g., Model IL 1400A, equipped with a suitable probe. An example irradiation is greater than 3 mW/cm2.
UV lamps typically have a “burn-in” period. UV lamps may also have a limited life (e.g., in the range of approximately 6,000 to 10,000 hours). UV lamps also typically lose irradiance (e.g., 10 to 40% of their initial lamp irradiance) over the lifetime of the lamp. Thus, it may be important to consider the effectiveness of new and old UV lamps in designing and maintaining oxidation values.
The light source may be disposed exterior to the light tube or sleeve, and the tube or sleeve may include a transparent or translucent member adapted to permit ultraviolet light emitted from the light source to irradiate the photoelectrode. The device may also utilize sunlight instead of, or in addition to, the light source.
Referring now to
In various embodiments, fitting 190 includes a fitting flange 420 to which bulkhead member 320 is coupled or releasably coupled. Fitting flange 420 may be integral to the fitting or part of a component coupled to fitting 190. In various embodiments, fitting flange 420 and bulkhead member 320 each defines one or more flange apertures 430 into which bolts or other fasteners (not shown) may be provided to help releasably couple and create a seal between bulkhead member 320 and fitting flange 420.
In various embodiments, multiple counterelectrodes may be electrically-coupled together (e.g., with first bus bars 440 or other conductive material (such as stainless steel)). In addition, multiple photoelectrodes may be electrically-coupled together with one or more second bus bars 450 or other conductive material. It should be appreciated that the bus bars may also be provided internally to a reactor apparatus (e.g., to help protect them from damage, to reduce potential leaking, etc.). If provided internally, the bus bars may be made of titanium.
In various embodiments, and referring now to
As shown in
In various embodiments, spigot member 520 and bulkhead member 510 also includes a tongue and groove feature. For example, in various embodiments, bulkhead member 510 may include a tongue or ring 570 that, when bulkhead member 510 is properly aligned with spigot member 520, will fit into a groove or channel 580 defined by spigot member 520 to help align (e.g., coaxially align) spigot member 520 and bulkhead member 510 relative to each other. Such ring 570 or inner ring may also help protect a sealing face 590 of bulkhead member 510 during shipping and handling. In various embodiments, the seal 560 is provided on spigot member 520 or flange 530 to allow easy visual access for inspection and cleaning of seal 560 to help ensure particular contaminants which may compromise the integrity of seal 560 are removed during servicing. A seal (e.g., O-ring) may be provided on the bulkhead flange as an alternate or additional configuration.
The configuration of the clamp, spigot member 520, and mating bulkhead member 510 may also improve ease of removal of system components, such as a reactor assembly coupled to or otherwise associated with or including bulkhead member 510. For example, spigot 520 and/or spigot flange 530 may be shaped and sized to allow the clamp to be rested on or around spigot member 520 (e.g., next to spigot flange 530) during removal and installation of bulkhead member 510. In addition, in various embodiments, a profile of bulkhead flange 540 provides an area or feature 600 that may be utilized to better grip bulkhead member 510 when removing it from the apparatus or otherwise relative to spigot member 520.
In various embodiments, one or more power supplies and/or ballasts are included or provided for powering each light source and/or for providing an electrical potential or bias to one or more of the counterelectrodes (e.g., cathodes) and photoelectrodes (e.g., anodes). In various embodiments, one or more power supplies and/or ballasts are electrically coupled to the light sources and/or the photoelectrodes and provided externally to the container, housing or apparatus. At least one pump may optionally be provided internally or externally to the housing to help facilitate transfer or movement of fluid or solution through each apparatus or a system of apparatus. The pump may also be used, for example, for circulation or recirculation.
Referring again to
In various embodiments, control panel 450 may also include one or more user interfaces 460. For example, in various embodiments, user interface 460 is used to configure, set-up, monitor and/or maintain one or more of the apparatus or systems described herein. The user interface may include a button or other control for implement a sampling of solution. For example, it may be desirable to sample solution before and after it is treated using an apparatus, device, system or method described herein. For example, in various embodiments, the apparatus or system includes two valves, one provided about at or about an input line for the apparatus or system, and the other provided about an output line for the apparatus or system. Such valves may be opened to help collect solution samples. These samples may be tested on-site and/or off-site (e.g., sent to a laboratory for testing). The testing may involve chemical analysis and/or biologic analysis (e.g., to determine bacteria counts and/or “xxx log kill” measurements).
Because such testing may be affected by polarity applied or provided to electrodes at the time of sampling and because testing results may be more accurate if sampling is conducted at a time when polarity is consistent between samples, the user interface in various embodiments may include a button or control (e.g., “START SMPL PROCESS” button) for placing the system or apparatus in a particular state of polarity (e.g., a positive or normal polarity or bias) for a predetermined or desired time period (e.g., two minutes) to allow sampling to occur during that time period.
In various embodiments, power supplies, ballasts, circuit boards and/or controls may be housed or otherwise provided in the electrical or control panel. The PECO system may also include temperature sensors provided at various positions (e.g., in each group of devices). In various embodiments, the electrical panels may include fans and/or heat sinks if desired. In various embodiments, the electrical panels may be provided in an environment away from hazardous or flammable reactions.
One or more power supplies may also be provided for supplying power to one or more UV lamps. One or more power supplies, or an alternative power supply, may also be provided for providing an applied voltage between the photoelectrode and counterelectrode. In one or more examples of embodiments, increasing the applied voltage increases photocurrent and/or chlorine production. In various embodiments, the applied voltage between the photoelectrode and the counterelectrode is provided to help ensure that electrons freed by photochemical reaction move or are moved away from the photoelectrode. The power supply may be an AC and/or DC power supply and may include a plurality of outputs.
One or more power supplies, in one or more examples of embodiments, may be connected to a power switch for activating or deactivating the supply of power. In one or more further examples of embodiments, a power supply, UV lamps, and or electrodes, may be connected to or in communication with programmable logic controller or other control or computer for selectively distributing power to the UV lamps and/or to the electrodes, including anodes and cathodes described herein.
In various embodiments, one or more power supplies are external to the system. However, one or more power supplies may be internal to the system (e.g., in an electrical panel or box coupled to the device(s)).
The power supply or an additional power supply may be connected to the terminals of the electrodes described hereinabove via, for example cable connection to the terminals, for providing a current, potential, voltage or bias to the electrodes as described in the described methods.
A temperature probe(s) or sensor(s) may also be provided in one or more examples of embodiments. For example, the temperature probe(s) may be positioned in the housing or the adapter of the UV light assembly. The temperature probe may monitor the temperature in the device or in the fluid within the respective device and communicate that temperature reading. Further the temperature probe may be in communication with a shut-off switch or valve which is adapted to shut the system down upon reaching a predetermined temperature.
A fluid level sensor(s) may also be provided which may communicate a fluid level reading. The fluid level sensor(s) may be positioned in the device. Further the fluid level sensor may be in communication with a shut-off switch or valve which is adapted to shut off the device or increase the intake of fluid into the device upon reaching a predetermined fluid value.
In one or more examples of embodiments, the device includes a carbon filter adapted to filter chlorine from the water. In various embodiments, the device includes a computer adapted to send one or more controlled signals to the existing power supplies to pulse the voltage and current.
In operation of the foregoing example embodiment, generally, in various embodiments, a method for reducing the level or amount of one or more contaminants in solution or fluid described includes introducing the solution into a housing or container or cell including: at least one light source; at least one photoelectrode (e.g., anode), wherein the at least one photoelectrode includes an anatase polymorph of titanium, a rutile polymorph of titanium, or a nanoporous film of titanium dioxide; and at least one counterelectrode (e.g., cathode). In various embodiments, flow of fluid or solution is facilitated past or along one or more photoelectrodes and/or counterelectrodes of a PECO apparatus. In various embodiments, one or more photoelectrodes are irradiated with UV light, and a first potential or bias is applied to one or more photoelectrodes and one or more counterelectrodes for a first period of time. In various embodiments, a second potential or bias is applied to the one or more photoelectrodes and counterelectrodes for a second period of time. As a result, in various embodiments, a contaminant level or amount in the solution introduced into the housing is reduced.
Contaminated fluid, such as contaminated water, may be pumped or otherwise provided or directed into an apparatus, or system. The water may be circulated and/or recirculated within the device. Multiple units, or reactors, may be connected and operated in series, which may result in increased space and time for contaminated fluid in the reactor(s) or device(s). Upon completion of processing, in various embodiments, the water exits the device ready for use, or circulated or recirculated through the device, one or more other devices, or system of devices, for further treatment or purification.
In various embodiments, in operation, the TiO2 photocatalyst is illuminated with light having sufficient near UV energy to generate reactive electrons and holes promoting oxidation of compounds on the anode surface.
Any temperature of aqueous solution or liquid water is suitable for use with the exemplary embodiments of the device such as the instant PECO devices. In various embodiments, the solution or water is sufficiently low in turbidity to permit sufficient UV light to illuminate the photoelectrode.
In various embodiments, photocatalytic efficiency is improved by applying a potential (i.e., bias) across the photoelectrode and counterelectrode. Applying a potential may decrease the recombination rate of photogenerated electrons and holes. In various embodiments, an effective voltage range applied may be in the range of −1 V to +15 V. In various embodiments, an electrical power source is adapted to apply an electrical potential in the range of 4 V to 12 V across the photoelectrode and counterelectrode. In various embodiments, the electrical power source is adapted to generate an electrical potential in the range of 1.2 V to 3.5 V across the photoelectrode and counterelectrode (or, 0 to 2.3 V vs. the reference electrode).
For various applications, including, for example fracking fluid or high-salinity applications, it may be desirable to reverse (e.g., periodically or intermittently) the potential, bias, polarity and/or current applied to or between the photoelectrode and the counterelectrode (e.g., to clean the photoelectrode and/or counterelectrode, or to otherwise improve the performance of the photoelectrode, counterelectrode, or device). In various embodiments, by reversing the potential, bias, polarity and/or current, the photoelectrode is changed (e.g., from an anode) into a cathode and the counterelectrode is changed (e.g., from a cathode) into an anode. In various embodiments, circuit boards utilized by the device or system of devices may be utilized to reverse the bias as described.
For example, in various embodiments, initially positive voltage is electrically connected to a positive charge electrode and negative voltage is electrically connected to a negative charge electrode. After a first period of time, the positive voltage is electrically connected to the negative charge electrode and the negative voltage is electrically connected to the positive charge electrode. After a second period of time, the positive voltage is electrically connected back to the positive charge electrode and the negative voltage is electrically connected back to the negative charge electrode. This reversal process may be repeated as necessary or desired.
The length of the first period of time and the second period of time may be the same. In various embodiments, however, the length of the first period of time and the second period of time are different. In various embodiments, the first period of time is longer than the second period of time.
The length of the first and second periods of time depends on a variety of factors including salinity, application, voltage, etc. For example, fracking fluid or high salinity fluid applications may require relatively more frequent reversal of potential, bias, polarity and/or current compared to fresh water applications. In various embodiments, the lengths of the first period of time relative to the second period of time may be in a ratio of from 3:1 to 50:1, and in one or more further embodiments from 3:1 to 25:1, and in one or more further embodiments from 3:1 to 7:1. For example, in various embodiments, the first period of time and second period of time is about 5 minutes to about 1 minute. Fresh water applications may require relatively less frequent reversal of potential, bias, polarity and/or current, and the lengths of the first period of time relative to the second period of time may be in a ratio of from 100:1 to 10:1. For example, in various embodiments, the first period of time and second period of time is about 60 minutes to a range of about 1 minute to about 5 minutes.
In various embodiments, the voltage applied between the photoelectrode and counterelectrode may not change during the first period of time of normal potential and during the second period of time of reverse potential. For example, in various embodiments (e.g., where the photoelectrode includes titanium and the apparatus and/or method are adapted for treatment of fracking or other high salinity solution) the voltage applied during the first period of time may be less than 9V (e.g., about 7.5V) and the voltage applied during the second period of time may be less than 9V (e.g., about 7.5V). In other various embodiments (e.g., where the photoelectrode includes titanium and the apparatus and/or method are adapted for treatment of fresh water) the voltage applied during the first period of time may be greater than 9V (e.g., about 12V) and the voltage applied during the second period of time may be greater than 9V (e.g., about 12V).
Maintaining the voltage in the first period of time and the second period of time may help to maintain and/or un-foul the photoelectrode to help make it more effective for removing contaminants through photoelectrocatalytic oxidation during the first period of time. However, maintaining the voltage under 9V in each period of time may cause a momentary disturbance in the removal of contaminants during the second period of time. For a variety of reasons, (e.g., to help minimize any such disturbance and/or to help cause electroprecipitation and/or electrocoagulation), in various embodiments, it may be advantageous to apply higher voltages (e.g., voltages greater than 9V) during the first period of time and second period of time. In various embodiments, applying higher voltages helps to promote an electrochemical process such as electroprecipitation and/or electrocoagulation during the second period of time, which process can help minimize any disturbance in removal of contaminants during the second period of time as well as offer advantages and benefits of such a process.
In various embodiments, the voltage is adjusted to control the rate of dissolution of the electrode. In various examples of embodiments, the voltage applied during the first period of time may be more than 9V (e.g., about 12V) and the voltage applied during the second period of time may be more than 9V (e.g., about 12V). Higher voltages may help optimize the effectiveness of the device in certain ways. Higher voltages may also lead to electroprecipitation or electrocoagulation of contaminants within or from the fluid. However, such higher voltages may also lead to anodic dissolution such as pitting and other degradation of the photoelectrode and/or counterelectrode, which may necessitate more frequent servicing of the PECO device (e.g., replacement of the photoelectrode (e.g., the foil) and counterelectrode).
In various embodiments, it may be advantageous (e.g., to help limit any anodic dissolution, or pitting or other degradation of the photoelectrode) to apply relatively lower voltages during the first period of time and relatively higher voltages during the second period of time. In various embodiments, e.g., in a fracking fluid application using a photoelectrode and a counterelectrode including titanium, the voltage applied during the first period of time may be less than 9V (e.g., about 7.5V) and the voltage applied during the second period of time may be more than 9V (e.g., about 12V for fracking fluid or higher salinity applications, to about 14V for fresh water applications). In various embodiments, during application of relatively lower voltage during the first period of time, contaminants are degraded (or the removal of contaminants is promoted) by photoelectrocatalytic oxidation, and during application of a relatively higher voltage during the second period of time, contaminants are degraded (or the removal of contaminants is promoted) by an electrochemical process such as electroprecipitation and/or electrocoagulation.
In various embodiments, during the second period of time, the counterelectrode or sacrificial electrode of titanium is dissolved at least in part by anodic dissolution. It is believed that a range of coagulant species of hydroxides are formed (e.g., by electrolytic oxidation of the sacrificial counterelectrode), which hydroxides help destabilize and coagulate the suspended particles or precipitate and/or adsorb dissolved contaminants.
In various embodiments, it is advantageous to apply relatively higher voltages during the first period of time and relatively lower voltages during the second period of time. In various embodiments, the voltage applied during the first period of time is more than 9V (e.g., about 12V) and the voltage applied during the second period of time is less than 9V (e.g., about 7.5V).
In various embodiments, the main reaction occurring at the counterelectrodes or sacrificial electrodes during the second period of time (e.g., during polarity reversal) is dissolution:
TI(s)→Ti4++4e−
In addition, water is electrolyzed at the counterelectrode (or sacrificial electrode) and photoelectrode:
2H2O+2e−→H2(g)+2OH− (cathodic reaction)
2H2O→4H++O2(g)+4e− (anodic reaction)
In various embodiments, electrochemical reduction of metal cations (Men+) occurs at the photoelectrode surface:
Men++ne−→nMeo
Higher oxidized metal compounds (e.g., Cr(VI)) may also be reduced (e.g., to Cr(III)) about the photoelectrode:
Cr2O72−+6e−+7H2O→2Cr3++14OH−
In various embodiments, hydroxide ions formed at the photoelectrode increase the pH of the solution which induces precipitation of metal ions as corresponding hydroxides and co-precipitation with metal (e.g., Ti) hydroxides:
Men++nOH−→Me(OH)n(s)
In addition, anodic metal ions and hydroxide ions generated react in the solution to form various hydroxides and built up polymers:
Ti4++4OH−→Ti(OH)4(s)
nTi(OH)4(s)−→Tin(OH)4n(s)
However, depending on the pH of the solution other ionic species may also be present. The suspended titanium hydroxides can help remove pollutants from the solution by sorption, co-precipitation or electrostatic attraction, and coagulation.
For a particular electrical current flow in an electrolytic cell, the mass of metal (e.g., Ti) theoretically dissolved from the counterelectrode or sacrificial electrode is quantified by Faraday's law
where m is the amount of counterelectrode or sacrificial electrode material dissolved (g), I the current (A), t the electrolysis time (s), M the specific molecular weight (g mol−1), z the number of electrons involved in the reaction and F is the Faraday's constant (96485.34 As mol−1). The mass of evolved hydrogen and formed hydroxyl ions may also be calculated.
In various embodiments, it may be advantageous (e.g., to help limit any anodic dissolution, or pitting or other degradation of the photoelectrode) to apply certain voltages (e.g., relatively higher voltages) during the first period of time and different voltages (e.g., relatively lower voltages) during the second period of time. In various embodiments (e.g., in a fracking fluid application using a counterelectrode including aluminum), the voltage applied during the first period of time may be about 6V to 9V (e.g., about 7.5V) and the voltage applied during the second period of time may be about 0.6V-12V. In various embodiments, during application of relatively higher voltage during the first period of time, contaminants are degraded (or the removal of contaminants is promoted) by photoelectrocatalytic oxidation, and during application of a relatively lower voltage during the second period of time, contaminants are degraded (or the removal of contaminants is promoted) by and electrochemical process such electroprecipitation or electrocoagulation.
In various embodiments, during the second period of time, an aluminum counterelectrode or sacrificial electrode is dissolved at least in part by anodic dissolution. It is believed that a range of coagulant species of hydroxides are formed (e.g., by electrolytic oxidation of the sacrificial counterelectrode), which hydroxides help destabilize and coagulate the suspended particles or precipitate and/or adsorb dissolved contaminants.
In various embodiments, the main reaction occurring at the counterelectrodes or sacrificial electrodes during the second period of time (e.g., during polarity reversal) is dissolution:
Al(s)→Al3++3e−
Additionally, water is electrolyzed at the counterelectrode (or sacrificial electrode) and photoelectrode:
2H2O+2e−→H2(g)+2OH− (cathodic reaction)
2H2O→4H++O2(g)+4e− (anodic reaction)
In various embodiments, electrochemical reduction of metal cations (Men+) occurs at the photoelectrode surface:
Men++ne−→nMeo
Higher oxidized metal compounds (e.g., Cr(VI)) may also be reduced (e.g., to Cr(III)) about the photoelectrode:
Cr2O72−+6e−+7H2O→2Cr3++14OH−
In various embodiments, hydroxide ions formed at the photoelectrode increase the pH of the solution which induces precipitation of metal ions as corresponding hydroxides and co-precipitation with metal (e.g., Al) hydroxides:
Men++nOH−→Me(OH)n(s)
In addition, anodic metal ions and hydroxide ions generated react in the solution to form various hydroxides and built up polymers:
Al3++3OH−→Al(OH)3(s)
nAl(OH)3(s)−→Aln(OH)3n(s)
However, depending on the pH of the solution other ionic species, such as dissolved Al(OH)2+, Al2(OH)24+ and Al(OH)4− hydroxo complexes may also be present. The suspended aluminum hydroxides can help remove pollutants from the solution by sorption, co-precipitation or electrostatic attraction, and coagulation.
For a particular electrical current flow in an electrolytic cell, the mass of metal (e.g., Al) theoretically dissolved from the counterelectrode or sacrificial electrode is quantified by Faraday's law
where m is the amount of counterelectrode or sacrificial electrode material dissolved (g), I the current (A), t the electrolysis time (s), M the specific molecular weight (g mol−1), z the number of electrons involved in the reaction and F is the Faraday's constant (96485.34 As mol−1). The mass of evolved hydrogen and formed hydroxyl ions may also be calculated.
The present invention, in one or more examples of embodiments, is directed to methods of treating an aqueous solution having one or more contaminants therein to help remove or reduce the amounts of contaminants. In various embodiments, the method includes providing an aqueous solution comprising at least one contaminant selected from the group consisting of an organism, an organic chemical, an inorganic chemical, and combinations thereof and exposing the aqueous solution to photoelectrocatalytic oxidization.
In one example of an application of the device described herein, the device uses photoelectrocatalysis as a treatment method for fracking fluid. While typically described herein as reducing levels of or removing contaminants from fracking fluid, it should be understood by one skilled in the art that photoelectrocatalysis of other contaminants can be performed similarly using the device (e.g., photoelectrocatalytic oxidation or PECO device).
In various embodiments, one or more contaminants are oxidized by a free radical produced by a photoelectrode, and wherein one or more contaminants are altered electrochemically (e.g., by electroprecipitation or electrocoagulation). In various embodiments, one or more contaminants are oxidized by a chlorine atom produced by a photoelectrode. In various embodiments, one or more contaminants are altered electrochemically (e.g., by electroprecipitation or electrocoagulation).
In one or more embodiments, the apparatus and methods utilize photoelectrocatalytic oxidation, whereby a photocatalytic anode is combined with a counterelectrode to form an electrolytic cell. In various embodiments, when the instant anode is illuminated by UV light, its surface becomes highly oxidative. By controlling variables including, without limitation, chloride concentration, light intensity, pH and applied potential, the irradiated and biased TiO2 composite photoelectrode may selectively oxidize contaminants that come into contact with the surface, forming less harmful gas or other compounds. In various embodiments, application of a potential to the photoelectrode provides further control over the oxidation products. Periodic or intermittent reversal of the potential may help further remove or reduce the amount of contaminants.
Generally, the contaminated water is introduced into a housing or container or cell including: a UV light; a photoelectrode, wherein the photoelectrode comprises an anatase polymorph of titanium, a rutile polymorph of titanium, or a nanoporous film of titanium dioxide; and a cathode. The photoelectrode is irradiated with UV light, and a first potential is applied to the photoelectrode and counterelectrode for a first period of time. A second potential is applied to the photoelectrode and counterelectrode for a second period of time. As a result, photoelectrocatalytic oxidization generates oxidants that destabilize emulsified oil, or emulsifications including oil, trapped in the contaminated water. This destabilization allows the emulsified oil, or emulsifications including oil, to be further separated from the contaminated water.
In various embodiments, emulsified oil is destabilized by a free radical produced by a photoelectrode, and wherein the emulsified oil is altered electrochemically (e.g., by electroprecipitation or electrocoagulation). In various embodiments, emulsified oil is destabilized by a chlorine atom produced by a photoelectrode. In various embodiments, emulsified oil is destabilized electrochemically (e.g., by electroprecipitation or electrocoagulation).
While
Referring back to
The system and method for removing and recovering oil from contaminated water disclosed herein has certain advantages. For examples, by incorporating a PECO system or unit into the oil recovery system, the efficiency of oil recovery is enhanced and the amount of time for recovery is reduced, as the PECO system destabilizes emulsifications of oil and water trapped in the contaminated water stream. The PECO system has a secondary advantage of removing impurities in the contaminated water while destabilizing emulsifications. As such, oil may be recovered from contaminated water in a shorter amount of time than other known systems, while removing unwanted impurities from the contaminated water. These and other advantages may be realized by the system and method disclosed herein.
As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.
It should be noted that references to relative positions (e.g., “top” and “bottom”) in this description are merely used to identify various elements as are oriented in the Figures. It should be recognized that the orientation of particular components may vary greatly depending on the application in which they are used.
For the purpose of this disclosure, the term “coupled” means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature.
It is also important to note that the construction and arrangement of the system, methods, and devices as shown in the various examples of embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied (e.g., by variations in the number of engagement slots or size of the engagement slots or type of engagement). The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various examples of embodiments without departing from the spirit or scope of the present inventions.
Although various representative examples of embodiments of this invention have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of the inventive subject matter set forth in the specification and claims. In some instances, in methodologies directly or indirectly set forth herein, various steps and operations are described in one possible order of operation, but those skilled in the art will recognize that steps and operations may be rearranged, replaced, or eliminated without necessarily departing from the spirit and scope of the present invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.
Moreover, some portions of the detailed descriptions herein are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the discussions herein, it is appreciated that throughout the present invention, discussions utilizing terms such as “receiving,” “sending,” “generating,” “reading,” “invoking,” “selecting,” and the like, refer to the action and processes of a computer system, or similar electronic computing device, including an embedded system, that manipulates and transforms data represented as physical (electronic) quantities within the computer system.
Although the present invention has been described with reference to particular embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
While this invention has been described in conjunction with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the examples of embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the invention. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/859,395, filed Jul. 29, 2013, entitled “System for Oil Recovery Utilizing Photoelectrocatalytic Oxidization and Method of Operation,” and U.S. Provisional Patent Application Ser. No. 61/878,505, filed Sep. 16, 2013, entitled “System for Oil Recovery and Treatment of Wastewater Utilizing Photoelectrocatalytic Oxidization and Method of Operation;” and is a Continuation-in-Part of U.S. patent application Ser. No. 14/035,993, filed Sep. 25, 2013, entitled “Apparatus and Method for Treating Aqueous Solutions and Contaminants Therein,” which is a Continuation application of U.S. patent application Ser. No. 13/769,741, filed Feb. 18, 2013, now U.S. Pat. No. 8,568,573, which is a Continuation application of U.S. patent application Ser. No. 13/544,721, filed Jul. 9, 2012, now U.S. Pat. No. 8,398,828, which claims priority to U.S. Provisional Patent Application Ser. No. 61/613,357, filed Mar. 20, 2012 and U.S. Provisional Patent Application Ser. No. 61/583,974, filed Jan. 6, 2012; and is a Continuation-in-Part of U.S. patent application Ser. No. 14/150,915, filed Jan. 9, 2014, entitled “Apparatus and Method for Treating Aqueous Solutions and Contaminants Therein,” which is a Continuation application of U.S. patent application Ser. No. 13/899,993, filed May 22, 2013, now U.S. Pat. No. 8,663,471, which is a Continuation application of U.S. patent application Ser. No. 13/796,310, filed Mar. 12, 2013, now U.S. Pat. No. 8,658,035, which is a Continuation application of U.S. patent application Ser. No. 13/689,089, filed Nov. 29, 2012, now U.S. Pat. No. 8,658,046, which claims priority to U.S. Provisional Patent Application Ser. No. 61/584,210, filed Jan. 6, 2012 and U.S. Provisional Patent Application Ser. No. 61/566,490, filed Dec. 2, 2011; each of which is hereby incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61859395 | Jul 2013 | US | |
| 61878505 | Sep 2013 | US | |
| 61613357 | Mar 2012 | US | |
| 61583974 | Jan 2012 | US | |
| 61584210 | Jan 2012 | US | |
| 61566490 | Dec 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13769741 | Feb 2013 | US |
| Child | 14035993 | US | |
| Parent | 13544721 | Jul 2012 | US |
| Child | 13769741 | US | |
| Parent | 13899993 | May 2013 | US |
| Child | 14150915 | US | |
| Parent | 13796310 | Mar 2013 | US |
| Child | 13899993 | US | |
| Parent | 13689089 | Nov 2012 | US |
| Child | 13796310 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14035993 | Sep 2013 | US |
| Child | 14445584 | US | |
| Parent | 14150915 | Jan 2014 | US |
| Child | 13544721 | US |
