INHIBITOR FROM A FLUID

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of the July 10, 2014 filing date of U.S. Provisional Application No. 62/022,745, which is incorporated by reference herein.

FIELD

Aspects of the present disclosure relate generally to the treatment of fluids, and more particularly to methods and systems for concentrating one or more target components from a fluid on a carbon material at elevated temperature, and optionally thereafter regenerating the loaded carbon material for subsequent use.

BACKGROUND

Water is a critical element in offshore or onshore upstream, midstream, and downstream activities within the oil and gas industry. In fact, produced water is typically the largest byproduct by volume in oil and gas recovery. Produced water may include water that exists in subsurface formations adjacent the layer comprising desired hydrocarbons and that flows to the surface during oil and gas production. In addition, produced water may include water which may be injected into a subsurface formation to provide additional volume and additional force to recover hydrocarbons from the formation. In either case, large volumes of formation water and injected water may be produced in oil and gas production. In some instances, additives may be included in the injected water to improve recovery and/or to prevent formation of unwanted byproducts. By way of example only, kinetic hydrate inhibitors (KHI's) may be included in injected water to prevent the formation of large hydrate crystals in the recovered hydrocarbons. New regulations for such additives, such as KHIs, however are forcing solutions for removing the additives from the produced water before storage, transport, or disposal thereof. Improved recovery solutions are thus needed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of the drawings that show:

FIG. 1 is a schematic of a system for removing a target component from a fluid in accordance with an aspect of the present invention.

FIG. 2 is a schematic of another system for removing a target component from a fluid in accordance with an aspect of the present invention.

FIG. 3 is a schematic showing a regenerated carbon material and steam being delivered from a regeneration unit to a concentrator unit in accordance with another aspect of the present invention.

DETAILED DESCRIPTION

The present inventors have found that a carbon material works surprisingly well as a concentrator of certain components in fluids at elevated temperature relative to other materials and lower temperatures, e.g., ambient temperatures. The processes and systems described herein are thus suitable for efficiently concentrating a target component on a carbon material as one or more quantities of a fluid are passed over or through the carbon material. In addition, it has been found that the loaded carbon material may be regenerated by a suitable regeneration process, such as wet air oxidation, and reused in a further concentration step. In some instances, the

regeneration process actually improves removal efficiency of the carbon material.

Thus, in accordance with an aspect, there is described a process for removing a target component from a fluid. The process comprises

concentrating the target component from the fluid on a carbon material in the presence of added energy (e.g., heat or heat energy) effective to increase a temperature of the fluid and such that an amount of the target component is removed from the fluid. The process further includes separating the resulting product from the concentrating step into a treated fluid and a loaded carbon material. In certain embodiments, the process may further include

regenerating the loaded carbon material such that an amount of the target component is removed from the loaded carbon material and a regenerated carbon material is provided.

By way of example only, the processes and systems described herein may be configured to recover kinetic hydrate inhibitors (KHIs) from produced water via an activated carbon material. In this embodiment, the process may thus include concentrating the KHIs from the produced water on the activated carbon material by contacting a quantity of the produced water with the activated carbon material. Thereafter, the resulting product may be separated into a loaded carbon slurry (with KHIs) and a treated produced water stream. Then, in a regeneration step, the KHIs in the loaded carbon slurry may be destroyed and the activated carbon material regenerated for subsequent use.

In accordance with another aspect, there is provided a system for removing a target component from a fluid comprising: a concentration circuit comprising one or more dedicated concentrator units, each unit comprising an effective amount of a carbon material for removing an amount of the target component from the fluid; an energy source effective to increase a

temperature of the fluid in each concentrator unit; and a separator in fluid communication with the one or more concentrator units, the separator comprising an inlet for receiving a product from the one or more concentrator units, wherein the separator separates the product into a treated fluid and a loaded carbon material comprising the target component.

As used herein, the term "about" refers to ± 10% of a stated value.

As used herein, the term "cloud point" refers to the temperature at which a solid substance begins to separate from solution and form a cloudy appearance.

As used herein, the term "effective amount" or the like means an amount suitable to bring about an intended result. As used herein, the term "kinetic hydrate inhibitor" refers to a

substance that is effective to decrease the rate of hydrate formation in a fluid in either a liquid or gas phase.

Now referring to the figures, FIG. 1 is a schematic illustration of a fluid treatment system 10 for removing one or more target components from a fluid 12 in accordance with an aspect of the present invention. The system 10 comprises a concentration circuit 14 comprising one or more dedicated concentrator units 16, an energy source 18, such as a heat source, in communication with the one or more concentrator units 16, and a separator 20 in fluid communication with the one or more concentrator units 16. Each concentrator unit 16 may comprise an effective amount of a carbon material 22 for removing an amount of one or more target components from the fluid 12.

As shown in the system 10 of FIG. 1 , a fluid 12 comprising a target component therein may be delivered or is otherwise provided to a

concentrator unit 16 in order to remove at least a portion of the target component from the fluid 12. The target component to be removed may comprise any component or compound which is able to be absorbed, adsorbed, or otherwise removed from the fluid 12 by the carbon material 22 within the concentration circuit 14. In an embodiment, the target component comprises an organic compound, such as one or more phenols, phthalates, hydrocarbons, and the like. In a particular embodiment, the target component comprises one or more kinetic hydrate inhibitors (KHIs) as are known in the art for retarding the formation of hydrates such as clathrate hydrates in a fluid, e.g., produced water.

KHIs typically comprise a polymer, a co-polymer, or mixtures thereof. Exemplary KHIs include but are not limited to poly(vinylpyrrolidone);

poly(vinylcaprolactam), polyacrylamides; co-polymers of vinylpyrrolidone, vinylcaprolactam; and/or acrylamides, poly(N-methyl-N-vinylacetamide); copolymers of N-methyl-N-vinylacetamide and iso-propylmethacrylamide; copolymers of N-methyl-N-vinylacetamide and acryloylpiperidine; co-polymers of N-methyl-N-vinylacetamide and methacryloylpyrrolidine, and co-polymers of N-methyl-N-vinylacetamide and acryloyl pyrrolidine; derivatives thereof, and combinations thereof. Other suitable KHIs are set forth in US Patent Nos. 7,994,374; 6,194,622; 6,107,531 ; 6,028,233; 6,015,929; and 5,936,040, the entirety of each of which are hereby incorporated by reference herein. KHIs also may be commercially available from a number of different sources such as Baker Hughes Inc. and Nalco Co.

The fluid 12 may be any suitable fluid which comprises an amount of one or more target components solubilized, suspended, or otherwise included therein. In an embodiment, the fluid 12 comprises one utilized in the recovery of oil and/or gas, such as produced water. As such, the fluid 12 may also include an amount of hydrocarbons therein, as well additives such as KHIs, suspended solids, and the like. In certain embodiments, the fluid 12 may instead or further comprise a glycol, such as ethylene glycol. Thus, for example, the fluid 12 may comprise a produced water stream that may include at least ethylene glycol and KHIs. In practice, ethylene glycol may be added onshore to produced water to prevent the produced water from freezing under particular conditions. Normally, ethylene glycol is not able to be recovered due to the KHIs present. Advantageously, removing KHIs via the systems and methods described herein, for example, allows for recovery of a treated fluid comprising produced water and/or ethylene glycol.

Referring again to FIG. 1 , a desired volume of the fluid 12 may be delivered to the concentrator unit 16 on a batch or semi-batch basis. In a semi-batch mode, some of the carbon material 22 (once loaded with a target component) may be periodically removed and passed along to the separator 20 from the concentrator unit 16. The volume of the fluid 12 to be provided to the concentrator unit 16 may be dependent on the concentration of the target component in the fluid 12, the amount of carbon material 22 in the

concentrator unit 16, the temperature at which the concentrating step(s) take place, or a number of other possible parameters as would be appreciated by the skilled artisan. In certain embodiments, additional "make up" carbon material 22 may be provided to the concentrator unit 16 as needed to ensure adequate carbon material 22 is present to remove the target component from the fluid 12.

Once provided to the concentrator unit 16, the concentrating of the target component on the carbon material 22 may take place. To accomplish this, each concentrator unit 16 of the circuit 14 may comprise a housing having a cavity therein for housing an effective amount of a carbon material 22 for removal of the target component from the fluid 12 when combined therewith. In addition, the concentrator unit 16 may comprise an open air vessel or a closed system. In an embodiment, the concentrator unit 16 may be in the form of an activated carbon-loaded aeration tank such as is described in U.S. Patent No. 7,972,512, the entirety of which is incorporated by reference herein. Alternatively, the concentrator unit 16 may comprise a packed vessel, such as a granular activated carbon (GAC) column, a GAC cartridge, or a GAC biofilter as are each known in the art.

The fluid 12 may be maintained with the concentrator units 16 for a duration and under conditions effective for the concentrator units 16 to remove (concentrate) a quantity of the target component from the fluid 12 and load the same onto the carbon material 22. In certain embodiments, for example, the residence time of the fluid within the concentrator units 16 may be from about 1 -100 minutes and in particular embodiments, from about 5-60 minutes. Optionally, the fluid 12 and the carbon material 22 may be mixed initially, periodically, or continuously throughout the concentrating step via suitable mixing apparatus. The resulting product from the combination of the mixed fluid 12 and the carbon material 22 may be in the form of a slurry or the like.

Although one system 10, input for the fluid 12, concentrator unit 16, heat source 18, outlet for the fluid 12, and separator 20 is shown for ease of understanding in FIG. 1 , it is understood that the present invention is not so limited and that a plurality of any of the components may be provided. It is merely important that with a given concentrator unit 16, an amount of fluid 12 is contacted with a carbon material 22 under conditions effective to

concentrate an amount of the target component from the fluid 12 onto the carbon material 22. In certain embodiments, this concentrating step may take place numerous times with different volumes of the fluid 12 with the same volume of carbon absorbent.

In accordance with an aspect, the present inventors have surprisingly found that the removal of the one or more target components in the fluid 12 may be further enhanced by the addition of energy to the fluid 12 and the carbon material 22 within the concentrator unit 16 from a suitable energy source 18, e.g., a heat source, in order to raise a temperature of the fluid 12 during the concentration process. For example, when the target component comprises a kinetic hydrate inhibitor (e.g., KHI), the removal efficiency of the KHIs by the carbon material 22 may be improved by heating the components to a predetermined temperature. In a particular embodiment, the

predetermined temperature comprises a temperature that is greater than a cloud point of the fluid 12 with the target component.

The "cloud point" for a given fluid may refer to a temperature at which a solid substance begins to separate from solution and form a cloudy appearance. While not wishing to be bound by theory, it is believed that at or above the cloud point, the presence of the added heat increases molecular motion such that intermolecular hydrogen bonding forces are overcome and the solubility of the target component (such as KHIs) may be decreased in the fluid 12. The resulting dispersed target component, e.g., KHIs, may be more easily trapped, adborbed, absorbed, or otherwise removed from the fluid 12 by the carbon material 22. In certain embodiments, it has been found that the increased removal of the target component occurs and/or the cloud point is reached when the fluid 12 is heated to a temperature of at least about 40° C. Thus, in one aspect, the systems and methods described herein may include heating the fluid 12 in the concentrator unit 16 to a temperature of at least about 40° C, and in a particular embodiment from about 45 to about 70° C. To provide the added heat to the concentrator units 16 and the contents therein, the energy source 18 may comprise any suitable apparatus or resource for providing an effective amount of heat or energy to the fluid 12 and/or the carbon material 22 to raise the fluid to a predetermined

temperature. In an embodiment, the energy source 18 comprises a source of steam, and in particular to a low pressure source of steam, e.g., steam below 50 psig (3.5 barg). In the case of KHIs, the addition of steam to the

concentrator units 16 may be of particular advantage since utilizing steam to heat the fluid 12 and carbon 22 may carry the advantage of eliminating fouling during the heating process. Fouling would likely occur, for example, with the use of heat exchangers in the concentrator unit 16 since the KHIs would likely fall out of solution and coat the heat exchange materials.

The carbon material 22 may comprise any type of carbon material and may be in any form suitable for removal of one or more target components in the fluid 12. In an embodiment, the carbon material 22 comprises activated carbon. Activated carbon is a form of carbon processed to have pores that significantly increase the available surface area for increased capacity for the target component to be removed therewith. The carbon material 22 may be derived from a source selected from the group consisting of wood,

bituminous, sub-bituminous, and lignite carbon. Further, the carbon 22 may be in any suitable form such as a powder or a granular material. Still further, the amount of carbon material 22 provided in each concentrator unit 16 may be any suitable amount and may be dependent such parameters as the expected concentration of the target component in the fluid 12, the volume of the fluid 12, and the like. By way of example only, the carbon material 22 may be present in an amount of from about 10 grams to about 50 grams per liter of fluid 12, and in a particular embodiment, about 25 grams per liter of fluid 12. As mentioned, the present inventors have found that the carbon material 22 works particularly well in the removal of certain target components, such as KHIs, from the fluid 12. Referring again to FIG. 1 , once a concentrating step has taken place in the concentrator unit 16 where the target component is loaded on the carbon material 22, at least a portion of the combined product 24 in the concentrator unit 16 may undergo separation into a treated fluid 26 and a loaded carbon material 28 comprising the target compound. In an embodiment, the loaded carbon material 28 may be in the form of a slurry having a solids percentage, such as from 10-30 %, or alternatively may be in any other suitable form.

In the embodiment shown, the combined product 24 is directed to a distinct location and apparatus, e.g., separator 20, from the concentrator unit 16 for the separation of combined product 24 into components 26, 28.

Alternatively, the separator 20 need not comprise a distinct apparatus from the concentrator unit 16. Instead, the structures of the separator 20 the concentrator unit 16 may be integrated with one another as appropriate such the concentrating and separating steps described herein may occur within the same housing. For an example, see U.S. Published Patent Application No. 2014/0061 134, the entirety of which is hereby incorporated by reference.

The separator 20 may comprise one or more clarifiers as are known in the art for carrying out a separation of the fluid 12 from the carbon material 22 (namely carbon material loaded with a target component). An exemplary clarifier is set forth in U.S. Patent No. 5,593,589, which is incorporated by reference herein. In another embodiment, the separator 20 may comprise a suitable filter or the like as is known in the art configured for providing a filtrate comprise treated fluid 26 and a concentrate comprising the loaded carbon material 28. In certain embodiments, flocculants and/or coagulants may also be added to enhance the settling of the carbon material 22 from the fluid 12 in the separator 20.

It is appreciated that the treated fluid 26 may be directed from the separator 20 to a suitable location or vessel for transport, storage, disposal, or the like of the treated fluid 26. In other embodiments, the treated fluid 26 may directed to one or more additional polishing steps for removal of dissolved organics, emulsified oil, or any other material desired to be removed from the treated fluid. Following the separation step, the treated fluid 26 may have a concentration of the target component which is less than a predetermined value. In a particular embodiment, when the target component comprises one or more KHIs, the treated fluid 26 may comprise a concentration of less than 100 ppm, and in a particular embodiment, less than 30 ppm.

In certain embodiments, the carbon material 22 may be utilized to concentrate the target component thereon until the carbon material 22 becomes "spent." In an embodiment, the carbon material 22 has become spent when the ability of the carbon 22 to remove further target component from the fluid 12 has become nearly or completely exhausted. For example, the carbon material 22 may be nearly spent or exhausted when the carbon material 22 requires at least twice the residence time to remove the same amount of component as a previous timeframe of the same duration. In other embodiments, the carbon material 22 may be utilized until the fluid 12 comprises less than a predetermined amount of the target component. The latter determination may be made by suitable quantitative or semi-quantitative methods, such as a chromatography technique as is known in the art. Once it has been determined that the concentration process on a quantity of the fluid 12 is complete, an amount of the combined product 24 may be directed from the concentrator unit 16 to the separator 20 as shown in FIG. 1 .

Referring now to FIG. 2, in accordance with another aspect, there is shown a system 10B which comprises the components of system 10, but also further includes equipment suitable for regenerating the loaded carbon material 28 such that the regenerated carbon material may be reused in a further concentration step. As shown in FIG. 2, the system 10B may include a regeneration circuit 30 comprising one or more regeneration units 32

(hereinafter "regeneration unit 32") for receiving an amount of loaded carbon material 28 (the carbon material 22 with the target component loaded thereon). The regeneration unit 32 treats the loaded carbon material 28 via a process which removes the target component from the loaded carbon material 28 to produce a regenerated carbon product 34. The regenerated carbon product 34 may be suitable for reuse in the concentration circuit 14, if desired, or otherwise may be directed for storage, transportation, disposal, or the like. As shown, in an embodiment, the regenerated product 34 may be directed back to a concentration unit 16 of the concentration circuit 14 for use therein. It is appreciated, however, that the present invention is not so limited.

Each regeneration unit 32 provided may comprise the necessary components effective to control pressure, temperature, input/output thereof in order to regenerate an amount of the loaded carbon material 28. In a particular embodiment, the regeneration unit 32 is configured to carry out a wet air oxidation (WAO) process on the loaded carbon material 28. Wet air oxidation is a well known process for the oxidation of soluble or suspended components in a fluid, such as water, using oxygen (with air as the source) as the oxidizing agent. Typically, the oxidation reactions occur at temperatures of 150° C to 320° C (275° F to 608° F) and at pressures from 10 to 220 barg (150 to 3200 psig). Exemplary wet air oxidation systems and processes are set forth in U.S. Patent Nos. 8,051 ,01 1 and U.S. Published Patent Application Nos. 20140251924; 20130008858; 20100252500; and 20050171390, the entirety of each of which is hereby incorporated by reference.

In an embodiment, the regeneration circuit 30 comprises at least one pump, at least one heater, a water source, and a source of pressurized oxygen-containing gas. In operation, an amount of the loaded carbon material 28 may be provided to the regeneration circuit 30 from the separator 20. Thereafter, an oxygenated liquid may travel through the loaded carbon material 28 at a suitable pressure and temperature for a suitable amount of time in order to oxidize a quantity of the target component loaded on the carbon material 22. Once a regenerated carbon material 34 is produced, the regenerated carbon material 34 may be directed back to the concentration circuit 14 for reuse therein or otherwise to a location or vessel for storage, disposal, or transport thereof. In accordance with one aspect, the

regenerated carbon material 34 may even exhibit improved removal properties for a target component (such as KHIs) after regeneration relative to virgin carbon material. The remaining liquid product 38 comprising the target components and/or byproducts thereof may be purged from the regeneration unit 32 as desired and directed to a location or vessel for storage, disposal, or transport thereof.

In certain embodiments, when the regenerated carbon material 34 is directed back to a concentrator unit 16, an amount of "make up" carbon material 36 may further be added to the concentrator unit 16 to provide the desired loading of carbon material 22 in the concentrator unit 16. Further, in certain embodiments, when a WAO process is carried out in the regeneration circuit 30, it is appreciated that steam may be provided as a byproduct of the WAO process. As shown in FIG. 3, this steam 40 (when produced) may optionally be utilized to provide a source of heat for the one or more concentrator units 16 as described above to heat the fluid 12. FIG. 3 illustrates both regenerated carbon material 34 and added heat (in the form of steam 40) being delivered from a regeneration unit 32 to a concentrator unit 16. In this instance, the steam 40 thus defines an energy source 18 (e.g., a heat source) for the concentrator unit 16.

In the embodiments described herein, it is appreciated that one or more inlets, outlets, pumps, valves, coolers, energy sources, flow sensors, or controllers (comprising a microprocessor and a memory), or the like may be included in any of the systems described herein for facilitating the

introduction, introduction, output, timing, volume, selection, and direction of flows of any of the components (e.g., liquids, slurries, or the like) therein. It is appreciated that a quantity of the components to be provided in any step of a process or system described herein may be readily determinable by the skilled artisan. In certain embodiments, the pumps utilized herein may comprise low pressure pumps such that the carbon material in forms 22, 24, 34, for example, is not crushed or pulverized as the material is moved through various process steps. Without limitation, exemplary pumps for use in the present invention include an air lift pump, a low shear centrifugal pump, a diaphragm pump, or the like. The function and advantages of these and other embodiments of the present invention will be more fully understood from the following examples. These examples are intended to be illustrative in nature and are not considered to be limiting the scope of the invention.

EXAMPLES

Example 1 : KHI removal via a Carbon Material 1 .1 . Equipment

Carbon absorption was performed by mixing samples of produced water with carbon in a beaker. The solution was heated to temperature and then the required dose of carbon was added and mixed for a specified time. Following the specified time, the solution was then filtered and the effluent was retained for analysis.

1 .2 Determination of Absorbent

A variety of absorbents were tested to determine the removal efficiency of the KHI. Synthetic produced water was made by adding 480 mLs of a 25% by volume. KHI solution to 20 liters of Dl water. The KHI used for testing was dissolved in water, not butoxyethanol. All carbon in the sample was due to KHI. A total carbon analysis was done to verify the KHI content and to get a baseline to determine KHI removal. The total carbon analysis was used as the indicator of KHI removal. The results of testing are presented in Table 1 . Filtered produced water was used to confirm there was no KHI loss due to the filtering process.

Table 1 . Absorbent Testing

Absorbent Type Total Carbon Reduction (%)

(mg/L)

Synthetic Produced Water 3600 —

Filtered Produced Water 3510 3%

Clay Based Absorbent 21 10 41 % Microsand 3350 7%

Activated Carbon (Wood) 55 98%

Activated Carbon (Bituminous) 590 84%

1 .3 Effect of Temperature

WPX carbon and produced water (PW) were used for testing the effect of temperature on the removal of KHI. Initial testing was performed with a dose of 25 g/L and a temperature ranging from 5-60 °C. All conditions achieved the same level of treatment. The testing was repeated using a lower dose of carbon and a shorter mix time to determine the effectiveness of temperature. The results are presented in Table 2.

Table 2 Results from Temperature Testing

As the temperature increased, the total carbon and high MW

compounds decreased. Of the temperatures tested, a temperature of 60 °C was determined to be effective, but a temperature of 45 °C also enhanced removal compared to room temperatures. 1 .4 Effect of Carbon Regeneration

Two different types of carbon were tested for KHI removal (SA20- wood; WPX- bituminous). Synthetic produced water was used for testing. The testing was performed at 45 °C with a one hour mixing time. The overall reductions varied from the different carbons. The wood based had almost no removal after regeneration. The WPX (bituminous) carbon had an increase in absorption after regeneration.

Table 3 Results from Regenerated Carbon Testing

As shown, the regeneration of WPX (bituminous) carbon increased overall KHI removal.

1 .5 Removal Summary

Based on carbon absorption testing, the use of bituminous based carbon (WPX) provided excellent results. The testing of varies carbons was not exhausted and other carbon could work equally or even better than WPX. The removal of KHI works best at temps of 45 °C or greater with relatively short contact times (5 minutes). The optimum carbon dose was 25 g/L, but this is highly dependent on the additional organic compounds in the produced water and the concentration of the KHI. The carbon absorption process is able to remove KHI to non-detectable concentrations and improve overall biodegradability. Example 2: Carbon Regeneration Testing

2.1 Test Equipment

The wet air regenerations were performed in a laboratory autoclave fabricated from 316 SS. The autoclave had a total volume of 750 ml_. A sample of carbon slurry was added to the autoclave. The autoclave was then closed and charged with sufficient compressed air to maintain residual oxygen following the oxidation. The charged autoclave was placed into the

heater/shaker mechanism and heated to 240 °C. The autoclave was held at temperature for 15 minutes (simulating 60 minutes in a continuous flow process), and then were immediately removed and quickly cooled to room temperature by quenching the autoclave in water. After cooling, the final pressure of the autoclave was measured. An offgas was analyzed for oxygen, nitrogen, carbon monoxide, carbon dioxide, hydrogen, methane and total volatile organic compounds using gas chromatograph procedures. After the autoclave was depressurized, the autoclave was opened and the regenerated carbon was removed, filtered, rinsed with Dl water, dried, and weighed.

In order to simulate multiple regeneration cycles, the carbon slurry solution was not removed from the autoclave until the final cycle. The offgas was analyzed for carbon components (CO2, and CO) and the carbon in the offgas was calculated to determine the overall carbon destruction.

2.2 Results and Discussion

For initial testing, five cycles of carbon regeneration was performed. The carbon was removed and weighed after each cycle to confirm the results obtained by the offgas. These five cycles achieved a good carbon balance with the activated carbon loss equivalent to the amount of CO and CO2 in the offgas. The overall attrition of the carbon was higher as compared to a traditional WAR system which has biomass included with the carbon. The first cycle had approximately 15% carbon loss and the following four cycles had 25-35% carbon loss. Typical WAR systems have approximately 10% carbon loss. The higher carbon loss may impact the overall economics of an absorption system.

Table 4 Results from Multi Cycle Carbon Regeneration Testing

WPX Cycle Cycle Cycle Cycle Cycle Carbon 1 2 3 4 5

Reported

Charge Conditions Units As

Oxidation

Temperature °c 240 240 240 240 240

Time at

Temperature min 15 15 15 15 15

SS SS ss ss

Autoclave Material SS 316 316 316 316 316

Autoclave Volume ml — — 750 750 750 750 750

Volume of Liquid

Charged ml 150 150 150 150 150

Air Charged psig — — 1000 1000 1000 1000 1000

Barometric Pressure mm Hg — — 722 730 736 739 730

Charge Gas

Temperature °c 23.5 23.5 23 23 23

Total Carbon added g/L — — 50 50 40 40 40

Reported

Analysis Results Units As

Carbon (in liquid) g/L c — 42.1 31.8 28.4 25.3 30.6

Carbon Recovery % c — 84.2 63.6 71.0 63.3 76.5

Carbon (converted

to CO/CO2) g/L c 7.5 14.0 12.2 10.1 6.6

% by

Total Solids % Weight 97.1 95.5 94.8 95.3 99.5 98.0

Total Suspended % by

Ash @550 C % Weight 10.4 1 1.9 14.0 18.3 28.7 35.8

PH — — — 3.73 3.73 3.90 4.07 4.37

Missing Carbon g/L c — 0.4 4.2 -0.6 4.6 2.8

91.6 101.5 88.5 93.0

Carbon balance % c 99.2% % % % %

Reported

Offgas Data Units As

Offgas Pressure psig — — 881 889 879 894 898

Offgas Temperature °c — — 20.2 18.2 17.6 19.5 22.7

Hydrogen ppm H ₂ <0.05 <0.05 <0.05 <0.05 <0.05

Carbon Dioxide % C0 ₂ 6.03 1 1.1 9.81 7.99 5.28

Oxygen % 0 ₂ 13.8 8.81 1 1.1 13.1 15.8

Oxygen Uptake g/L 0 ₂ 31.3 47.0 40.0 33.0 24.5

Nitrogen % N ₂ 77.9 80.4 81.0 80.4 79.2

Methane ppm CH ₄ <50 <50 <50 <50 <50

Carbon Monoxide % CO — 0.259 0.436 0.351 0.280 0.183

THC ppm CH3CH3 <10 <10 <10 <10 <10 The same process was repeated for additional carbons except only the offgas were monitored and the carbon destruction was calculated from the CO2 and CO in the offgas. The PAC20B, which is also a bituminous carbon, had similar carbon destruction as WPX over the three cycles. The

Hydrodarco C, which is a lignite based carbon, had a much lower carbon loss for the 3 cycles. Additional carbon optimization may reduce the overall carbon losses for the absorption system.

Table 5 Results from Multi Cycle Carbon Regeneration Testing of Additional Carbons

2.3. Absorption, Separation, and Oxidation (ASO) System

A system was constructed comprising a mix chamber. The carbon concentration was 1 - 2.5% by weight. Low pressure steam was direct injected to heat the produced water to 45-60 °C. No heat exchanger was used since it would likely foul due to the solids that form with the KHI. After a contact time of at least 5 minutes, the mixture was flowed to a separation vessel (e.g., a clarifier in this instance, but also could be a filter). The treated produced water exited the system and the concentrate, which consisted of 10- 30% total solids, was sent to an WAO system for regeneration.

While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.