Destruction of PFAS Via an Oxidation Process and Apparatus Suitable for Transportation to Contaminated Sites

Patent metadata

Field	Value
Publication number	US-2023227336-A1
Application number	US-202217991124-A
Country	US
Kind code	A1
Filing date	Nov 21, 2022
Priority date	Jun 28, 2019
Publication date	Jul 20, 2023
Grant date	—

Abstract

Per- and polyfluoroalkyl substances (PFAS) are destroyed by oxidation in supercritical conditions. PFAS in water can be concentrated and prepared for destruction in a pretreatment phase. Following annihilation of the PFAS in supercritical conditions to levels below 5 parts per trillion (ppt), the water effluent can be used to recover heat, returned to sub-critical conditions, and then released back into the environment.

First claim

1 - 36 . (canceled)

37 . A method of destroying PFAS in a PFAS-containing mixture, the method comprising:
separating the PFAS-containing mixture into a mineral enriched fraction and a mineral depleted fraction using a separation procedure; heating the mineral-enriched fraction to volatize PFAS into a vapor; recovering PFAS from the vapor; and reacting the recovered PFAS with an oxidant under supercritical conditions.

38 . The method of claim 37 wherein the step of heating results in a brine having 5 ppt PFAS or less.

39 . The method of claim 37 wherein the step of heating comprises heating to at least 150° C.

40 . The method of claim 37 comprising, prior to the step of reacting the PFAS with an oxidant, super-saturating the PFAS-containing mixture with air and passing the PFAS-containing mixture into a tank and reducing pressure in the tank such that bubbles are generated in the mixture create a foamed mixture.

41 . The method of claim 37 wherein, prior to the step of heating the mineral-enriched fraction to volatize PFAS into a vapor, the PFAS-containing mixture is treated with acid.

42 . The method of claim 39 wherein the step of heating comprises heating up to 300° C.

43 . The method of claim 37 wherein the recovered PFAS is recombined with all of a portion of the mineral depleted fraction.

44 . A method of destroying PFAS, comprising:
providing an aqueous solution comprising water and PFAS; subjecting the aqueous solution to a pretreatment or a separation procedure to produce a clean water fraction and a briny concentrated fraction in which the PFAS concentration is greater than the aqueous solution; preheating the PFAS-concentrated fraction at subcritical conditions; passing the preheated concentrated fraction into a heated pre-reactor where the concentrated fraction is converted to supercritical conditions at a first temperature; removing salt from the briny concentrated fraction to produce a brine-reduced fraction; and passing the brine-reduced fraction to a reactor where the fraction is subjected to oxidation under supercritical conditions reducing the concentration of PFAS in the brine-reduced fraction to produce an effluent of clean, hot water.

45 . The method of claim 44 further comprising transferring heat from the clean hot water solution to the aqueous solution in the heat exchanger in the preheating step.

46 . A system for destroying PFAS, comprising:
a first inlet conduit for passing a PFAS-containing stream into an inlet of a SCWO reactor; an outlet of the SCWO reactor connected to a salt separator; the salt separator comprising an effluent outlet configured to pass effluent clean water from the salt separator.

47 . The system of claim 46 wherein the SCWO reactor comprises a pipe having interior walls coated with a coating that resists corrosion by HF.

48 . The system of claim 46 wherein the SCWO reactor comprises a flowpath configured to flow a fluid that is consistently downward with respect to gravity.

49 . The system of claim 46 wherein the SCWO reactor comprises the salt separator comprises an effluent outlet configured to pass effluent clean water from the salt separator to a heat exchanger that is configured to heat the effluent clean water that leaves the heat exchanger.

50 . The system of claim 46 wherein the SCWO reactor comprises a transpiring wall reactor.

51 . The system of claim 46 comprising a cyclonic separator disposed upstream of the first inlet.

52 . The system of claim 49 where heat exchanger comprises a tube-in-tube heat exchanger.

53 . The system of claim 50 where the transpiring wall reactor comprises a curved floor or ceiling.

54 . The system of claim 46 comprising an electronic board designed to control current to the SCWO reactor to decrease corrosion.

55 . The system of claim 46 wherein the SCWO reactor comprises multiple injection points.

56 . The system of claim 46 comprising a water softener comprising an ion exchange resin, calcium hydroxide, or a chelating agent.

57 . The system of claim 55 wherein the SCWO reactor is configured to provide an after burner.

58 . The system of claim 46 wherein the SCWO reactor comprises a sacrificial electrode.

59 . The system of claim 46 comprising a mixing pipe configured to mix effluent from the SCWO reactor, comprising:
an injection pipe configured for flow of the effluent from the SCWO reactor into the mixing pipe;
an inlet pipe configured to supply cooling water to the mixing pipe where the effluent from the SCWO reactor can be mixed with the cooling water; and
an outlet configured for flow of the mixed, cooled effluent.

Assignees

• Battelle Memorial Institute

Inventors

• Dejarme Lindy E
• Dasu Kavitha
• Sirabian Russell R
• Buurma Christopher F
• Ellis Jeffrey
• Miller Michael M
• Garbark Dan
• Bryant Nathan
• Tallarico John
• Casciano Joseph
• Winecki Slawomir
• Holley David
• James Joshua
• Brown Keith
• Hendry Doug
• Argumedo Darwin
• Frank Aaron
• Scheitlin Christopher Gordon

Classifications

• C02F1/441 Primary

  by reverse osmosis · CPC title

• C02F1/04

  by distillation or evaporation · CPC title

• C02F1/722

  Oxidation by peroxides · CPC title

• C02F2101/36

  containing halogen · CPC title

• B01J3/008

  Processes carried out under supercritical conditions · CPC title