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US 11,407,666 B2Granted
Salt separation and destruction of PFAS utilizing reverse osmosis and salt separation
AssigneeBattelle Memorial Institute
InventorsStephen H. Rosansky, Michael Miller, Patrick Norris, Darwin Argumedo, Douglas Hendry, Ian Haggerty, Keith Brown, Joshua James, Joseph Casciano, Slawomir Winecki, Vivek Lal, Tom McGuinness
Life of this patent
Estimating the term…
Abstract
Per- and polyfluoroalkyl substances (PFAS) are destroyed by oxidation in supercritical conditions. PFAS in water is concentrated in a reverse osmosis step and salt from the resulting solution is removed in supercritical conditions prior to destruction of PFAS in supercritical conditions.
Claims19
A method of destroying PFAS, comprising:
- providing an aqueous solution comprising water and PFAS;
- subjecting the aqueous solution to reverse osmosis to produce a clean water fraction and a briny concentrated fraction in which the PFAS concentration is at least 50% greater than the aqueous solution;
- preheating the briny concentrated fraction in a heat exchanger to form a preheated concentrated fraction that is at subcritical conditions;
- passing the preheated concentrated fraction into a heated pre-reactor where the briny concentrated fraction is converted to supercritical conditions at a first temperature causing sodium chloride to precipitate;
- removing at least a portion of the sodium chloride to produce a brine-reduced fraction;
- passing the brine-reduced fraction to a reactor where the fraction is subjected to oxidation under supercritical conditions wherein the concentration of oxidant and/or temperature is higher than in the pre-reactor;
- producing a clean hot water solution having a concentration of PFAS that is at least 90% less than the aqueous solution;
- and, optionally,
- transferring heat from the clean hot water solution to the aqueous solution in the heat exchanger in the preheating step;
- wherein the clean hot water solution passes through a post heat exchanger that is positioned downstream of the pre-reactor and then passes through a pre heat exchanger that is positioned upstream of the pre-reactor.
7 more elements
A method of destroying PFAS, comprising:
- providing an aqueous solution comprising water and PFAS;
- subjecting the aqueous solution to reverse osmosis to produce a clean water fraction and a briny concentrated fraction in which the PFAS concentration is at least 50% greater than the aqueous solution;
- preheating the briny concentrated fraction in a heat exchanger to form a preheated concentrated fraction that is at subcritical conditions;
- passing the preheated concentrated fraction into a heated pre-reactor where the briny concentrated fraction is converted to supercritical conditions at a first temperature causing sodium chloride to precipitate;
- removing at least a portion of the sodium chloride to produce a brine-reduced fraction;
- passing the brine-reduced fraction to a reactor where the fraction is subjected to oxidation under supercritical conditions wherein the concentration of oxidant and/or temperature is higher than in the pre-reactor;
- producing a clean hot water solution having a concentration of PFAS that is at least 90% less than the aqueous solution;
- and, optionally,
- transferring heat from the clean hot water solution to the aqueous solution in the heat exchanger in the preheating step;
- wherein the briny concentrated fraction in which the PFAS concentration is at least 50% greater, that results from the reverse osmosis and prior to the step of removing at least a portion of the sodium chloride, comprises a precipitate and further comprising a step of adding an acid to dissolve the precipitate.
7 more elements
A system for destroying PFAS, comprising:
- a reverse osmosis system;
- a conduit from the reverse osmosis system to a salt separator;
- wherein the salt separator comprises a first tube leading into a collector vessel and a second tube passing out of the collector vessel, wherein the collector vessel comprises an inner diameter that is at least twice as large as the inner diameter of the first tube;
- wherein the first tube projects at least 5 cm further into the collector vessel than the second tube;
- and
- a conduit from the salt separator to a supercritical reactor.
3 more elements
A system for destroying PFAS, comprising:
- a reverse osmosis system;
- a conduit from the reverse osmosis system to a salt separator;
- wherein the salt separator comprises a first tube leading into a collector vessel and a second tube passing out of the collector vessel, wherein the collector vessel comprises an inner diameter that is at least twice as large as the inner diameter of the first tube;
- and
- a conduit from the salt separator to a supercritical reactor and further comprising a first heat exchanger disposed in the conduit between the reverse osmosis system and the salt separator;
- wherein, during operation, the first heat exchanger exchanges heat between a subcritical PFAS-containing aqueous stream and a return stream of PFAS-free water from the supercritical reactor.
3 more elements
A transcritical hydrocyclone, comprising:
- a conical chamber comprising:
- an inlet for introducing supercritical fluid into the conical chamber tangentially along an inner wall of the cyclone;
- a top outlet adapted for flow of a supercritical fluid;
- an exit pipe adapted for flow of a liquid;
- a cone disposed in the conical chamber adapted such that a channel can be formed between the inner wall of the cyclone and an outer wall of the cone;
- and
- wherein the cone comprises a bottom opening;
- wherein the bottom opening comprises a diffuser extending down from the cone;
- wherein the diffuser comprises a plurality of openings.
6 more elements
A method of destroying PFAS, comprising:
- providing an aqueous solution comprising water and PFAS;
- subjecting the aqueous solution to reverse osmosis to produce a clean water fraction and a briny concentrated fraction in which the PFAS concentration is at least 50% greater than the aqueous solution;
- preheating the briny concentrated fraction in a heat exchanger to form a preheated concentrated fraction that is at subcritical conditions;
- passing the preheated concentrated fraction into a heated pre-reactor where the briny concentrated fraction is converted to supercritical conditions at a first temperature causing sodium chloride to precipitate;
- removing at least a portion of the sodium chloride to produce a brine-reduced fraction;
- passing the brine-reduced fraction to a reactor where the fraction is subjected to oxidation under supercritical conditions wherein the concentration of oxidant and/or temperature is higher than in the pre-reactor;
- producing a clean hot water solution having a concentration of PFAS that is at least 90% less than the aqueous solution;
- and, optionally,
- transferring heat from the clean hot water solution to the aqueous solution in the heat exchanger in the preheating step;
- wherein the pre-reactor and/or the reactor comprise reactor walls coated with a ceramic coating that is resistant to hydrofluoric acid;
- wherein the ceramic comprises at least 80 wt % chromium oxide.
8 more elements
Dependencies are inferred from the claim text.