Gaseous halogenated hydrocarbon compound destruction in an alkaline, hydrothermal environment, and related methods and systems

Abstract

A method for breaking down a halogenated hydrocarbon (HHC) compound that exists in the gaseous state at atmospheric conditions, includes the following: a) adding the HHC compound to an alkaline solution having a pH greater than 7 to generate a mixture of reagents; b) pressurizing the mixture of reagents to keep the alkaline solution in the liquid state and promote increased solubilization of the HHC compound in the alkaline solution; c) heating the mixture of reagents to a temperature within the range of 20° Celsius to 400° Celsius; and d) holding the mixture of reagents at the temperature in a reactor vessel for a period of time to separate a halogen atom from the HHC compound via alkaline hydrolysis.

Description

[0001] GASEOUS HALOGENATED HYDROCARBON COMPOUND DESTRUCTION IN AN ALKALINE, HYDROTHERMAL ENVIRONMENT, AND RELATED METHODS AND SYSTEMS

[0002] STATEMENT OF FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0003] [1] This invention was made with government support under ER18-1501 awarded by the Strategic Environmental Research and Development Program (SERDP). The government has certain rights in the invention.

[0004] CROSS-REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE

[0005] [2] This application claims priority from U.S. Provisional Patent Applications 63 / 563,456 filed 10 March 2024 and titled “ALKALINE HYDROTHERMAL CONVERSION OF HYDROFLUOROCARBONS”. This application also incorporates by this reference the entirety of this U.S. Provisional Patent Application.

[0006] BACKGROUND

[0007] [3] Halogenated hydrocarbon (HHC) compounds, especially those in the gaseous state at normal atmospheric conditions (15°C (Celsius) and 0.101 MPa (Megapascals)), are frequently used as refrigerants. For example, hydrofluorocarbon compounds (HFCs), such as HFC-134a (CF3CH2F), HFC-23 (CF3H) and HFC-152a (C2H4F2), as well as hydrochlorofluorocarbon compounds (HCFCs), and chlorofluorocarbon compounds (CFCs) are often used as the working fluid in an air conditioner’s refrigeration cycle.

[0008] [4] Unfortunately, these compounds are potent and long-lived greenhouse gases. HFCs are also known to decompose into fluorocarbons such as trifluoroacetic acid (TFA) in the atmosphere, which now exist in concerning concentrations in rainwater. Other gaseous halogenated hydrocarbon compounds that are also potent and long-lived greenhouse gasses include chloroform, 1 H-perfluoroheptane, 1 H-perfluoropropane, 1 H- perfluorooctane, fluoromethane (CFH3), difluoromethane (CH2F2), fluoroform (CF3H), 1 ,1 ,1 ,2-tetrafluoroethane (CF3CH2F), 1 ,1 ,1 -Trifluoroethane (C2H3F3), difluoroethane (C2H4F2), pentafluoroethane (C2HF5), 2,3,3,3-Tetrafluoropropene (C3H2F4), and a hydrofluoroolefin, such as R-1234yf, or 2,3,3,3-Tetrafluoropropene.

[0009] [5] While existing thermal, chemical, and plasma destruction processes can breakdown halogenated hydrocarbon compounds, there is a need for more cost- effective HHC compound destruction technologies that are proven to completely mineralize HHC compounds - that is, separating halogen atoms from the carbon atoms that they are bonded with and forming a salt or some other inorganic compound with the removed halogen atoms. By themselves, HHC compounds are resistant to thermal degradation, e.g., fluoroform (CF3H) is stable up to a temperature of about 900°C, and in the presence of water vapor up to about 600°C.

[0010] [6] Several technologies have been investigated as a general HHC compound destruction process. However, few destructive technologies have robustly demonstrated the ability to consistently and completely break all carbon-halogen bonds in a halogenated hydrocarbon compound.

[0011] [7] Thus, there is a need for a more effective way to breakdown / destroy HHC compounds.

[0012] SUMMARY

[0013] [8] In one aspect of the invention, a method for breaking down a halogenated hydrocarbon (HHC) compound that exists in the gaseous state at atmospheric conditions, includes the following: a) adding the HHC compound to an alkaline solution having a pH greater than 7 to generate a mixture of reagents; b) pressurizing the mixture of reagents to keep the alkaline solution in the liquid state and promote increased solubilization of the HHC in the alkaline solution; c) heating the mixture of reagents to a temperature within the range of 20° Celsius to 400° Celsius; and d) holding the mixture of reagents at the temperature in a reactor vessel for a period of time to separate a halogen atom from the HHC compound via alkaline hydrolysis.

[0014] [9] By adding a halogenated hydrocarbon compound that exists in the gaseous state at atmospheric conditions (15°C and 0.101 MPa) to a heated solution of water and alkali, the HHC compound more readily reacts with the alkali compound via alkaline hydrolysis to separate the halogen atoms from one or more carbon atoms of the HHC compound. This, in turn, reduces the amount of time that it takes to break down an HHC compound, or separate most, if not all, of the halogen atoms from their corresponding carbon atoms, and thus allows one to run the reaction as a continuous flow process through a reactor vessel.

[0015]

[0010] In another aspect of the invention, a system for breaking down a halogenated hydrocarbon compound that exists in the gaseous state at atmospheric conditions, includes a reactor vessel, a heater, a first pump, and a second pump. The reactor vessel is operable to hold a mixture of reagents that includes a halogenated hydrocarbon compound that exists in the gaseous state in atmospheric conditions, an alkali, and water, while alkaline hydrolysis separates a halogen atom from the HHC in the mixture. The heater is operable to heat the mixture of reagents to a temperature within the range of 20° Celsius to 400° Celsius. The first pump is operable to pressurize the mixture of reagents to keep the water from entering a gaseous state. And, the second pump is operable to pressurize the HHC compound in the gaseous state to inject the HHC compound into the alkali and water solution.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017]

[0011] FIG. 1 shows a schematic view of a method for breaking down a halogenated hydrocarbon compound (HHC), according to an embodiment of the invention.

[0018]

[0012] FIG. 2 shows a schematic view of a system for breaking down a halogenated hydrocarbon compound (HHC), according to an embodiment of the invention. DETAILED DESCRIPTION

[0019]

[0013] FIG. 1 shows a schematic view of a method for breaking down a halogenated hydrocarbon (HHC) compound, according to an embodiment of the invention. An HHC compound is any hydrocarbon molecule that includes one or more halogen atoms bonded to one or more carbon atoms, and that exists in the gaseous state at standard atmospheric conditions, i.e., 15°C and 0.101 MPa. A halogen atom is an atom of any of the following chemical elements: fluorine, chlorine, bromine, and iodine. The method comprises adding, at step 10, an HHC compound to an alkaline solution having a pH greater than 7 to generate a mixture of reagents. Then, at step 12, the mixture of reagents is pressurized to keep the alkaline solution in the liquid state promote increased solubilization of the HHC compound in the alkaline solution. Then, at step 14, the mixture of reagents is heated to a temperature within the range of 20°C to 400°C. Then, at step 16, the mixture of reagents is held at the temperature in a reactor vessel for a period of time to separate a halogen atom from the HHC compound via alkaline hydrolysis.

[0020]

[0014] By adding a halogenated hydrocarbon compound that exists in the gaseous state at atmospheric conditions (15°C and 0.101 MPa) to a heated solution of water and alkali, the HHC compound more readily reacts with the alkali compound via alkaline hydrolysis to separate the halogen atoms from one or more carbon atoms of the HHC compound. This, in turn, reduces the amount of time that it takes to break down an HHC compound, or separate most, if not all, of the halogen atoms from their corresponding carbon atoms, and thus allows one to run the reaction as a continuous flow process through a reactor vessel.

[0021]

[0015] Alkaline hydrolysis of an HHC compound is a reaction in which a hydroxide ion (OH-) enriched in solutions having a pH greater than 7 reacts with a compound to promote cleavage of one or more carbon-halogen bonds in the structure. Here, in this example, the HHC compound is a hydrofluorocarbon (HFC) compound such as fluoromethane (CFH3), and the negative ion is a hydroxide ion from sodium hydroxide (NaOH). In the reaction mechanism, the OH- ion promotes deprotonation of the most acidic proton in CFH3 to form a carbanion species (CFH2-), which is unstable and undergoes further elimination and hydroxide substitution reactions that lead to release of the bonded fluorine atom as inorganic fluoride ion (F_). Sodium ions from the sodium hydroxide solution can combine with the eliminated (freed) F_molecules to form aqueous NaF.

[0022]

[0016] The alkali (another term for base) that forms the alkaline solution may be any desired alkali, and the concentration of the alkali in solution may be any desired concentration. For example, in this embodiment, the alkali includes sodium hydroxide (NaOH), and the concentration of the sodium hydroxide ranges between 0.01 Moles per liter to 19 Moles per liter. Likewise, the pH of the alkaline solution may be any desired pH. For example, in this and other embodiments the pH of the solution is 7 or greater. In other embodiments, the alkali may include potassium hydroxide (KOH), ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), calcium hydroxide (Ca(OH)2, sodium carbonate (Na2CO3), and / or potassium carbonate (K2CO3).

[0023]

[0017] Still referring to FIG. 1, the HHC compound that the method may be used to break down may be any desired HHC compound. For example, here the HHC compound is a hydrofluorocarbon (HFC) compound, specifically fluoromethane (CFH3). The method, however, may also be used to break down other HHC compounds such as chloroform, difluoromethane (CH2F2), fluoroform (CF3H), 1 ,1 ,1 ,2-tetrafluoroethane (CF3CH2F), 1 ,1 ,1 -Trifluoroethane (C2H3F3), difluoroethane (C2H4F2), pentafluoroethane (C2HF5), 2,3,3,3-Tetrafluoropropene (C3H2F4), a hydrofluoroolefin, such as R-1234yf, and 2,3,3,3-Tetrafluoropropene, a perfluoroalkane, such as 1 H-perfluoropropane,

[0024] 1 H-perfluorooctane, and 1 H-perfluoroheptane, a hydrochlorofluorocarbon compound such as perfluorocarbon and chlorofluorocarbon.

[0025]

[0018] The HHC compound may be added to the alkaline solution while in the gaseous state by bubbling the HHC compound into the alkaline solution. Alternatively, the HHC compound may be added to the alkaline solution in the liquid state. Because HHC compounds have low solubility in water, the HHC compound in the gaseous or liquid state does not dissolve well in the alkaline solution and thus does not widely disperse or mix throughout the alkaline solution. Thus, the area of the interface between the alkaline solution and the HHC compound is small relative to the amount or mass of HHC compound added to the alkaline solution. The interface between the alkaline solution and the HHC compound is where the HHC compound dissolves into the alkaline solution for reactions to occur in the liquid phase, and may be where reactions occur. Because the area of the interface is small, the rate at which alkaline hydrolysis breaks down the HHC compound is limited. Increasing this surface area can increase the rate at which alkaline hydrolysis breaks down the HHC compound by increasing the overall rate of dissolution for HHC compound into the alkaline solution. So, when the HHC compound is added to the alkaline solution in the gaseous state, the HHC compound may be injected as many small bubbles through a diffuser. This increases the total surface area where the HHC compound can dissolve into solution and where the hydroxide ion may attack the HHC compound relative to the total amount or volume of HHC injected. When the HHC is injected into the alkaline solution in the liquid state, one can increase the area of the interface where alkaline hydrolysis occurs by mixing the mixture of reagents or deforming the liquid bubble of HHC in the alkaline solution by forcing the liquid bubble against and around an obstacle such as a baffle in the reactor vessel.

[0026]

[0019] Other embodiments of the method are possible. For example, when the HHC compound is added to the alkaline solution in the gaseous state, the method may also include diverting back to a subsequent stream of alkaline solution any gaseous HHC compounds that do not react with the previous stream of alkaline solution after passing through the reactor vessel, so that the gaseous HHC compound has a second chance at being broken down by alkaline hydrolysis in the reactor vessel. For another example, when the HHC compound is to be added to the alkaline solution in the liquid state, the method may also include cooling the HHC compound, pressurizing the HHC compound, or both to put the gaseous HHC compound into the liquid state. For yet another example, the method may also include removing heat from the mixture of reagents after the mixture leaves the reactor vessel, and then applying the removed heat to a subsequent mixture of reagents before the subsequent mixture enters the reactor vessel (discussed in greater detail in conjunction with FIG. 2). For yet another example, the method may include a recovery step in which dissolved F_in the reaction products is reacted with a calcium or magnesium compound (e.g., CaCl2, Ca(OH)2, MgCh) to remove fluoride as CaF2 MgF? so that the hydroxide ions may be used in future alkaline hydrolysis reactions. In still yet another example, the method may include adding a catalyst to the mixture of reagents to promote the speed, ease, and efficiency of the alkaline hydrolysis of the HHC compound. The catalyst may be a metal oxide, such as tetragonal zirconium dioxide (t-ZrCh), zerovalent iron (ZVI), ruthenium (Ru) supported on a carbon matrix, and / or palladium also supported on a carbon matrix. With the addition of a catalyst, the amount of alkali consumed in the alkaline hydrolysis reaction, or the duration, or the temperature, or the pressure of the alkaline hydrolysis reaction, or any combination of these aspects of the reaction may be modified as desired.

[0027]

[0020] Still referring to FIG. 1, the mixture of reagents may be heated to any desired temperature between 20 °C and 400 °C, and may be pressurized to any desired pressure between 0.1 MPa and 50 MPa to keep the water in the alkaline solution in the liquid state throughout the reaction. For example, in this and other embodiments the reagent mixture is heated to a temperature between 20 °C and 120 °C. For most HHC compounds, the temperatures in this range provide enough thermal energy to the reagent mixture to substantially promote alkaline hydrolysis of the HHC compound. At these temperatures, the water in the alkaline solution will remain in the liquid state at 0.1 MPa (standard atmospheric pressure), so the reagent mixture can react at 0.1 MPa. In other embodiments, the reagent mixture may be pressurized above 0.1 MPa at a temperature between 20 °C and 120 °C to promote dissolution of the HHC compound in the liquid phase, promoting the alkaline hydrolysis reactions. In other embodiments, the reagent mixture may be heated to a temperature between 120 °C and 400 °C, and the reagent mixture may be pressurized to between 0.1 and 50 MPa. Because water boils at 100 °C at 0.1 MPa, pressurizing the reagent mixture above 0.1 MPa will keep the water in the reagent mixture from entering the gaseous state.

[0028]

[0021] Still referring to FIG. 1, the mixture of reagents may be held in the reactor vessel for any desired period of time to separate most, if not all, of the halogen atoms from their corresponding carbon atoms in the halogenated hydrocarbon compound via alkaline hydrolysis. For example, in this and other embodiments the period of time ranges from thirty seconds to sixty minutes. More specifically, when the HHC compound being broken down is a perfluoroalkane, the perfluoroalkane and alkaline solution are held in the reactor vessel for at least one minute, at a temperature between 250 °C and 400 °C, and at a pressure of 2 MPa.

[0029]

[0022] FIG. 2 shows a schematic view of a system 20 for breaking down a halogenated hydrocarbon compound (HHC), according to an embodiment of the invention. The system 20 performs the method discussed in conjunction with FIG. 1 , and includes a reactor vessel 22, a heater 24, a first pump 26, and a second pump 28. The reactor vessel 22 holds the mixture of reagents while alkaline hydrolysis separates a halogen atom from the HHC compound in the mixture. The heater 24 heats the mixture of reagents to a temperature within the range of 30 °C to 400 °C. The first pump 26 pressurizes the alkaline solution, and thus, the mixture of reagents after the HHC compound has been added to the alkaline solution, to keep the water in the solution from entering the gaseous state. And, the second pump 28 pressurizes the HHC compound (here shown in the gaseous state) to inject the HHC into the alkali and water solution.

[0030]

[0023] The reactor vessel 22 may be configured as desired to hold the mixture of reagents during alkaline hydrolysis under the various reaction conditions discussed in conjunction with FIG. 1 - specifically 30 °C to 400 °C, and 0.1 MPa to 50 MPa. For example, in this and other embodiments the reactor vessel 22 is made of a material that resists corrosion in the caustic environment that the alkaline hydrolysis occurs in. More specifically, the material may include a nickel alloy, such as Inconel 625 or Inconel 600. This material also provides good strength to withstand the high pressures that the alkaline hydrolysis may be performed at. The reactor vessel 22 also has a cylindrical shape to facilitate the flow of the reagent mixture through the reactor while the mixture undergoes the reaction. In this configuration, the reagent mixture continuously flows through the reactor vessel 22 while it undergoes alkaline hydrolysis. Also, the reactor vessel 22 is configured to house the heater 24 so that the mixture is heated to the desired reaction temperature while the mixture flows through the reactor vessel 22. In other embodiments, the reactor vessel 22 may not be configured to facilitate flow through it, but rather configured to promote the alkaline hydrolysis reaction of the reagent mixture in a batch process where the mixture is kept in the reactor vessel 22 and not allowed to flow through the reactor vessel 22 until the reaction completes, and then is removed from the reactor vessel 22. In such configurations, the reactor vessel 22 may be spherical. In still other embodiments, the reactor vessel 22 may not be configured to house the heater 24, and instead, the heater 24 may be located upstream from the reactor vessel 22.

[0031]

[0024] Other embodiments of the reactor vessel 22 are possible. For example, the reactor vessel 22 may be configured to minimize the effect of phase separation in the mixture of reagents, which can limit the rate at which alkaline hydrolysis breaks down the HHC compound. Examples of such configurations that promote mixing of the reagent mixture include: (i) configuring the interior chamber of the reactor 22 into a helical or spiral shape that provides a relatively high surface-to-volume ratio for the chamber, (ii) positioning ribs and baffles within the interior chamber of the reactor 22, (iii) changing the flow direction of the reagent mixture within the internal chamber of the reactor 22 to mitigate stationary pockets where the low-density fluid (Liquid HHC) could be trapped and remain trapped, and (iv) positioning high-velocity jets to mix the reagent mixture.

[0032]

[0025] The heater 24 may be any desired heater capable of generating the heat required to increase the temperature of the mixture to the temperature desired for the alkaline hydrolysis reaction. For example, in this and other embodiments the heater 24 includes an electrically resistive heating element that generates heat by resisting the flow of electricity through it. In other embodiments, the heater 24 may include a combustion chamber or nozzle and generate heat by burning a fuel such as natural gas. This allows the system 20 to operate in locales that do not have an adequate, if any, supply of electricity.

[0033]

[0026] The first pump 26 may be any desired pump capable of pressurizing the alkaline solution and, thus, the mixture of reagents after the HHC compounds have been added. And the second pump 28 may be any desired pump capable of boosting the pressure of the HHC compound in the gaseous state so that the HHC compound may be added to the pressurized alkaline solution. By pressurizing the mixture, the first pump 26 promotes a compressed liquid state of the alkaline solution and controls the flow of the reagent mixture through the reactor vessel 22. In this and other embodiments, the first pump 26 draws a highly concentrated solution of NaOH 30 from the container 32, and water 34 from the container 36, and combines these into the alkaline solution that will receive the HHC compound. The pressure in the reagent mixture is controlled by the back-pressure regulator 38 by not allowing the reagent mixture to flow rapidly through the reactor vessel 22 when the pump 26 pressurizes the alkaline solution. Because of this, the back pressure regulator 38 also functions to reduce the pressure in the reacted mixture (the mixture that has left the reactor vessel 22) to ambient conditions. The pressure in the mixture at which the back-pressure regulator 38 allows the mixture to flow toward the discharge tank 40 is set and controlled by the pressure control valve 42 of the back-pressure regulator 38. The second pump 28 receives HHC compounds in the gaseous state from the canister 44.

[0034]

[0027] Still referring to FIG. 2, the system 20 also includes other components, each of which may be configured as desired. For example, in this and other embodiments, the system 20 includes a heat exchanger 46. The heat exchanger 36 removes heat from the reacted mixture and applies most of the removed heat to a mixture of reagents in a subsequent stream or batch before the subsequent stream of reagents enters the reactor vessel 22. This allows one to reduce the amount of heat generated by the heater 24, and protects downstream components of the system 20 from excessive heat. In other embodiments, the system 20 may include a component (not shown) for diverting back to a subsequent stream or batch of alkaline solution any gaseous HHC compounds that did not react with the previous alkaline solution passing through the reactor vessel 22, so that the gaseous HHC compound has a second chance at being broken down by alkaline hydrolysis in the reactor vessel.

[0035]

[0028] The preceding discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

What is claimed is:1 . A method for breaking down a halogenated hydrocarbon compound (HHC) that exists in the gaseous state at atmospheric conditions, the method comprising: adding a halogenated hydrocarbon compound (HHC) that exists in the gaseous state at atmospheric conditions to an alkaline solution having a pH greater than 7 to generate a mixture of reagents; pressurizing the mixture of reagents to keep the alkaline solution in the liquid state and promote increased solubilization of the HHC compound in the alkaline solution; heating the mixture of reagents to a temperature within the range of 20° Celsius to 400° Celsius; and holding the mixture of reagents at the temperature in a reactor vessel for a period of time to separate a halogen atom from the HHC via alkaline hydrolysis.

2. The method of claim 1 wherein the halogenated hydrocarbon compound is a hydrofluorocarbon compound (HFC) that includes one of the following compounds: fluoromethane (CFH3), difluoromethane (CH2F2) fluoroform (CF3H), 1 ,1 ,1 ,2-tetrafluoroethane (CF3CH2F), 1 ,1 ,1 -Trifluoroethane (C2H3F3), difluoroethane (C2H4F2), pentafluoroethane (C2HF5), 2,3,3,3-Tetrafluoropropene (C3H2F4), and a hydrofluoroolefin, such as R-1234yf.

3. The method of claim 1 wherein the halogenated hydrocarbon compound is hydrogenated perfluoroalkane, such as 1 H-perfluoropropane,1 H-perfluorooctane, or 1 H-perfluoroheptane.

4. The method of claim 1 wherein the halogenated hydrocarbon compound includes at least one of the following compounds: a hydrochlorofluorocarbon compound, a perfluorocarbon compound and a chlorofluorocarbon compound.

5. The method of claim 1 wherein the halogenated hydrocarbon compound is chloroform.

6. The method of claim 1 wherein the alkaline solution includes at least one of the following: sodium hydroxide (NaOH), potassium hydroxide (KOH), and ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), calcium hydroxide (Ca(OH)2, sodium carbonate (Na2CO3), and potassium carbonate (K2CO3).

7. The method of claim 1 wherein adding the halogenated hydrocarbon compound includes injecting the compound in the gaseous state into the alkaline solution.

8. The method of claim 7 further comprising diverting gaseous HHC that did not react with the alkaline solution after passing through the reactor vessel, to an alkaline solution having a pH greater than 7 to generate another mixture of reagents to be subsequently held at the temperature in the reactor vessel for a period of time to separate a halogen atom from the HHC via alkaline hydrolysis.

9. The method of claim 1 wherein adding the halogenated hydrocarbon compound includes at least one of the following: pressurizing the compound, and cooling the compound, to put the compound into a liquid state, and then adding the compound in the liquid state into the alkaline solution.

10. The method of claim 1 wherein the mixture is held in the reactor vessel at a pressure between 0.1 Megapascals (MPa) and 50 MPa.11 . The method of claim 1 wherein the period is between 5 seconds and 60 minutes.

12. The method of claim 1 wherein: the halogenated hydrocarbon compound is a hydrofluorocarbon compound, the temperature is between 20°C and 120°C, and the mixture is held in the reactor vessel at a pressure of at least 0.1 Megapascals.

13. The method of claim 1 wherein: the halogenated hydrocarbon compound is a hydrogenated perfluoroalkane compound the temperature is between 250°C and 400°C, the pressure of the mixture is at least two Megapascals (MPa), and the mixture is held in the reactor vessel for at least one minute.

14. The method of claim 1 wherein: the halogenated hydrocarbon compound is a hydrochlorofluorocarbon compound, and the temperature is between 250°C and 400°C.

15. The method of claim 1 wherein the mixture of reagents continuously flows through the reactor vessel.

16. The method of claim 1 wherein adding a halogenated hydrocarbon compound (HHC) to an alkaline solution includes continuously injecting the halogenated hydrocarbon compound into the alkaline solution.

17. The method of claim 1 further comprising agitating the mixture while the mixture is held in the reactor vessel.

18. The method of claim 1 further comprising removing heat from the mixture of reagents after the mixture leaves the reactor vessel, and applying the removed heat to a subsequent mixture of reagents before the subsequent mixture enters the reactor vessel.

19. The method of claim 1 further comprising contacting the mixture with a catalyst.

20. The method of claim 19 wherein the catalyst includes one of the following: tetragonal zirconium dioxide (t-ZrC ), zerovalent iron (ZVI), ruthenium supported on carbon (Ru / C), and palladium supported on carbon (Pd / C).21 . A system for breaking down a halogenated hydrocarbon compound (HHC) that exists in the gaseous state at atmospheric conditions, the system comprising: a reactor vessel operable to hold a mixture of reagents that includes: a halogenated hydrocarbon compound (HHC) that exists in the gaseous state in atmospheric conditions, an alkali, and water, while alkaline hydrolysis separates a halogen atom from the HHC in the mixture, wherein, the reactor vessel is sized and configured to maintain pressure on the mixture to prevent the water in the mixture from entering the gas phase during alkaline hydrolysis; a heater operable to heat the mixture of reagents to a temperature within the range of 20° Celsius to 400° Celsius; a first pump operable to pressurize the mixture of reagents to keep the water from entering a gaseous state; and a second pump operable to pressurize the HHC in the gaseous state to inject the HHC into the alkali and water solution.

22. The system of claim 21 wherein the reactor vessel is configured to hold the mixture of reagents for a period of time while the reagents continuously flow through the reactor vessel, wherein the period of time equals the time required to separate all of the halogen atoms from the HHC compound in the mixture of reagents.

23. The system of claim 21 wherein the reactor vessel is configured to hold a volume of the mixture of reagents, while the mixture of reagents does not continuously flow through the reactor, until most of the halogen atoms in the HHC compound in the mixture of reagents are separated.

24. The system of claim 21 wherein the reactor vessel includes a baffle operable to increase the ratio of the surface area to the volume of the HHC compound that is not dissolved in the alkaline solution as the reagent mixture flows through the reactor vessel.

25. The system of claim 21 wherein the reactor vessel has an interior chamber that is helical in shape to provide a relatively high surface-to-volume ratio for the interior chamber.

26. The system of claim 21 further comprising a mixer operable to mix the reagent mixture while the reagent mixture is held in the reactor vessel.

27. The system of claim 21 further comprising a diffuser operable to inject the halogenated hydrocarbon compound in the gaseous state into the reactor vessel.

28. The system of claim 21 further comprising a compressor operable to compress the halogenated hydrocarbon compound in the gaseous state into a liquid state.

29. The system of claim 21 further comprising a heat exchanger operable to remove heat from the mixture of reagents after the mixture exits the reactor vessel, and apply the removed heat to a subsequent mixture of reagents before the subsequent reagent mixture enters the reactor vessel.

30. The system of claim 21 further comprising a recovery system operable to separate a halogen atom from the alkali metal that the halogen atom is bonded with, and reuse the alkali metal.31 . The system of Claim 21 further comprising a bed of catalysts material for contacting the mixture of reagents with a catalyst material.

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