Salt Separation and Destruction of PFAS Utilizing Reverse Osmosis and Salt Separation

1 - 24 . (canceled)

25 . A method of salt separation from an aqueous PFAS solution comprising:

providing an aqueous PFAS solution comprising a salt;

preheating the aqueous solution to a temperature to form a supercritical heated composition;

passing the supercritical heated composition into a transcritical hydrocyclone;

a transcritical hydrocyclone, comprising:

a conical chamber;

a top outlet;

an exit pipe; and

a cone disposed within the conical chamber wherein the cone does not seal the top outlet or exit pipe, and a conical channel is formed between the inner wall of the transcritical hydrocyclone and an outer wall of the cone;

cooling the outer wall of the transcritical hydrocyclone via a heat exchanger, causing an inner wall of the transcritical hydrocyclone to be cooler than the supercritical heated composition;

passing the supercritical heated composition tangentially into the conical chamber through an inlet opening of the transcritical hydrocyclone;

cooling the supercritical heated composition to form a layer of aqueous solution that is cooled to subcritical temperatures along the inner wall of the transcritical hydrocyclone;

draining the layer of the aqueous solution cooled to subcritical temperatures downward through an exit pipe; and

passing a portion of the supercritical heated composition in the conical chamber at supercritical temperatures out of the conical chamber through the top outlet.

26 . The method of claim 25 wherein the heat exchanger is a fluid heat exchanger.

27 . The method of claim 26 wherein the fluid heat exchanger comprises water as a coolant.

28 . The method of claim 25 wherein the top outlet of the transcritical hydrocyclone is shaped as a pipe which extends out of the conical chamber and partially into the conical chamber.

29 . The method of claim 28 wherein the cone further comprises a top opening and a bottom opening and wherein the top outlet pipe passes through the top opening of the cone.

30 . The method of claim 29 wherein the top outlet pipe and the top opening of the cone are connected by a threaded connection with a lock nut and/or a washer.

31 . The method of claim 30 comprising adjusting the cone closer or further away from the exit pipe.

32 . The method of claim 28 wherein the bottom opening of the cone comprises a diffuser comprising a plurality of openings.

33 . The method of claim 32 wherein the diffuser extends into the exit pipe.

34 . The method of claim 32 wherein the plurality of openings is oriented at an angle counter to the direction of fluid flow.

35 . The method of claim 32 wherein the plurality of openings has a combined open area that is at least two times or at least three times the cross-sectional area of the conical channel.

36 . The method of claim 32 wherein the plurality of openings is oriented at an angle counter to the direction of fluid flow and has a combined open area that is at least two times or at least three times the cross-sectional area of the conical channel.

37 . The method of claim 25 further comprising collecting the aqueous solution cooled to subcritical temperatures in a two-phase gravity separator and separating the salt from the aqueous solution via the two-phase gravity separator.

38 . The method of claim 25 wherein the diameter of the top outlet is smaller than the diameter of the exit pipe.

39 . A method of destroying PFAS in a SCWO system, wherein the SCWO system comprises a conduit from a source container to a heat exchanger and a conduit from the heat exchanger to a SCWO reactor; comprising: providing to the SCWO system an aqueous solution comprising water and PFAS;

adding an oxidant to the aqueous solution;

adding a fuel to the aqueous solution;

passing the aqueous solution with added oxidant and fuel into the SCWO reactor and subjecting the aqueous solution to supercritical water oxidation in the SCWO reactor; and

producing a clean effluent having a concentration of PFAS that is more than 100,000 times less than the first concentration of PFAS; and

wherein, after start-up, no external heating is provided to the SCWO system.

40 . The method of claim 39 wherein the system is disposed in a trailer.

41 . The method of claim 39 wherein the system comprises an RO pretreatment and a step of salt separation.

42 . The method of claim 39 comprising passing at least a portion of the effluent through a heat exchanger to heat the aqueous solution.

43 . The method of claim 39 wherein the fuel comprises an alcohol.

44 . The method of claim 39 wherein the oxidant comprises an oxyanion species, ozone, or peroxy acid.