Processes and apparatus for converting polyfluoroalkyl and perfluoroalkyl substances

Abstract

Process and apparatus for converting polyfluoroalkyl and perfluoroalkyl substances (PFAS). The PFAS is oxidized to anionic fluoride species using an oxidation reaction zone, preferably a thermal oxidation apparatus. A treatment zone is utilized for at least a portion of the oxidation zone effluent before it is discharged into the atmosphere or otherwise released. The treatment zone may include a dry adsorbent injection zone, a selective catalytic reduction zone, a wet scrubber zone, a carbon bed, an ion exchange zone, or any combination thereof.

Description

Technical Field

[0001] (Description of Priority) This application claims priority to U.S. Non-Provisional Patent Application No. 18 / 620,189, filed on March 28, 2024, which claims priority to U.S. Provisional Patent Application No. 63 / 518,029, filed on August 7, 2023, the entire content of which is incorporated herein by reference.

[0002] (Field of the Invention) The present invention generally relates to processes and apparatus for removing and converting polyfluoroalkyl and perfluoroalkyl substances.

Background Art

[0003] Poly- and perfluoroalkyl substances (PFAS) are "forever chemicals" that are extremely stable and persist in the environment. These forever chemicals are associated with adverse effects on the kidneys, liver, blood and immune system. Examples of such chemicals are surfactants used in industrial and consumer products, for example, fire-fighting foams, alkaline cleaners, paints, non-stick cookware, carpets, upholstery, shampoos, floor polishes, fog suppressants, semiconductors, photographic films, pesticide formulations, food packaging, masking tapes and denture cleaners.

[0004] The EPA has a list of more than 179 PFAS known or suspected to be toxic, and this list is expected to grow given that there are more than 12,000 different PFAS in existence. Currently, the EPA recommends a maximum limit of less than 70 ppt for PFAS, while stricter EPA regulations and limits have been proposed.

[0005] In view of the health risks associated with PFAS and their environmental impact, there is a continuing need for processes and apparatus that effectively and efficiently remove and convert PFAS.

Summary of the Invention

[0006] The present invention enables the removal and conversion of PFAS. The PFAS may be oxidized in a thermal oxidation apparatus, and the oxidized effluent is then treated in a treatment zone. The treatment zone may include a dry adsorbent injection zone, a wet scrubber zone, a carbon bed, a selective catalytic reaction zone, and / or an ion exchange zone.

[0007] The process of the present invention can be used with liquid PFAS and allows the flow to be injected into a thermal oxidation apparatus without the need for separate evaporation equipment. Furthermore, direct injection reduces residence time and minimizes the size of the required equipment.

[0008] Accordingly, the present invention provides a process for converting polyfluoroalkyl and perfluoroalkyl substances (PFAS) in at least one embodiment, comprising: oxidizing a feed stream containing liquid PFAS in an oxidation zone to provide an oxidized effluent containing a reduced amount of liquid PFAS compared to the feed stream; and treating the oxidized effluent in a treatment zone to provide a treated effluent, wherein the treatment zone includes a dry adsorbent injection zone, a selective catalytic reaction zone, a wet scrubber zone, a carbon bed, an ion exchange zone, or any combination thereof.

[0009] 90–99.9999% of the PFAS in the supply stream can be thermally oxidized in the thermal oxidation zone.

[0010] Oxidation can be carried out at temperatures between 500°C and 2,300°C.

[0011] The residence time of PFAS in the thermal oxidation zone can range from 0.1 to 30 seconds.

[0012] This process may further include cooling the oxidized effluent in a thermal reduction zone before processing in the processing zone.

[0013] The treatment zone may include a dry adsorbent injection zone, and the process includes mixing reactants with oxidized effluent to provide a treated effluent, wherein the reactants include salts having sodium, calcium, potassium, magnesium, aluminum, silicon, or any combination thereof in solution or mixture. The reactants may be a mixture of fresh reactants and recycled reactants. The process may include quenching the treated effluent from the treatment zone. The dry adsorbent injection zone may include a filtration zone configured to separate the treated effluent and provide residual effluent and vent gas flows. The process may include recirculating the residual effluent to the dry adsorbent injection zone as at least a portion of the reactants. The treatment zone may include a selective catalytic reaction zone, which may receive a vent gas flow from the filtration zone.

[0014] The treatment zone may include a wet scrubber zone, and the process may also include mixing an aqueous caustic flow with the oxidized effluent to provide a treated effluent. The aqueous caustic flow may contain sodium, calcium, potassium, magnesium, or any combination thereof. The process may also include separating the treated effluent into a liquid flow and a vent gas flow. The liquid flow may be mixed with the feed flow before introducing the feed flow into the thermal oxidation zone, or the liquid flow may be sent to the thermal oxidation zone as a quenched fluid, or both. The treatment zone may include a carbon bed, an ion exchange zone, or both, and the process may also include sending the liquid flow to the carbon bed or ion exchange zone before the liquid flow is mixed with the feed flow or sent as a quenched fluid.

[0015] The treatment zone may include a carbon bed, an ion exchange zone, or both, and may also include sensors configured to provide measurements, and the carbon bed or ion exchange zone may receive the liquid portion of the treated effluent. The process may include determining the fluorine concentration in the liquid portion of the treated effluent from the measurements. The process may further include monitoring the fluorine concentration in the liquid portion of the treated effluent. The process may include adjusting process conditions if the fluorine concentration is outside a predetermined range.

[0016] The process may include thermally reducing the temperature of the oxidation zone effluent before processing.

[0017] Further aspects, embodiments, and details of the present invention, all of which can be combined in any manner, are described below in the detailed description of the invention. [Brief explanation of the drawing]

[0018] One or more exemplary embodiments of the present invention will be described below in conjunction with the figures in the following drawings. [Figure 1] The process flow diagrams shown are those according to one or more embodiments of the present invention. [Figure 2] The process flow diagrams shown are those according to one or more embodiments of the present invention. [Figure 3] The process flow diagrams shown are those according to one or more embodiments of the present invention. [Figure 4] The process flow diagrams shown are those according to one or more embodiments of the present invention. [Modes for carrying out the invention]

[0019] As described above, the present invention enables the removal and conversion of PFAS. The PFAS may be oxidized in a thermal oxidation apparatus, and the oxidized zone effluent is sent to a treatment zone before the treated oxidized effluent is discharged into the atmosphere / environment or released in any other way.

[0020] As used herein, "PFAS" means fluorine-containing compounds, including polyfluoroalkyl and perfluoroalkyl substances, which contain at least one fully fluorinated methyl or methylene carbon atom. Commonly manufactured, used, and detected compounds include perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutane sulfonic acid (PFBS), perfluoropentanesulfonic acid (PFPS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptanesulfonic acid (PFHpS), perfluorononanesulfonic acid (PFNS), or perfluorodecanesulfonic acid (PFDS), and hexafluoropropylene oxide dimer acid (HFPO-DA). This list is not intended to be exhaustive and is merely illustrative. Additional PFAS compounds can be found, for example, in the definitions provided by the EPA. Furthermore, it should be understood that "PFAS" also refers to intermediate compounds produced during the conversion of the original PFAS compound.

[0021] As used herein, the term “substantially” can mean an amount of at least 90%, preferably 95%, and optimally 99% by weight of the compound or class of compounds in the flow.

[0022] As shown in the diagram, the process flow lines in the diagram can be interchangeably referred to as lines, pipes, feeds, flows, products, or streams.

[0023] As used herein, the term "zone" can refer to a region comprising one or more pieces of equipment and / or one or more subzones. The equipment may include one or more reactors or reaction vessels, heaters, exchangers, pipes, pumps, compressors, and controllers. In addition, pieces of equipment such as reactors, dryers, or vessels may further comprise one or more zones or subzones.

[0024] With these general principles in mind, one or more embodiments of the present invention are described with the understanding that the following description is not intended to be limiting.

[0025] Referring to FIG. 1, an apparatus 10 for converting PFAS receives a feed stream 12 containing liquid PFAS. In various embodiments, the feed stream 12 is a liquid feed stream comprising PFAS in liquid form, either PFAS in a liquid phase or dissolved solid-phase PFAS. It is contemplated that the feed stream 12 comprises 0.01 wt% PFAS, or alternatively 10 wt% PFAS. However, these amounts are merely illustrative and not intended to be limiting.

[0026] The feed stream 12 is sent to an oxidation zone 14 comprising at least one reaction vessel 16. In the oxidation zone 14, PFAS is oxidized to anionic fluoride species, among other components. In a preferred embodiment, the oxidation zone 14 comprises a thermal oxidation zone 18, and in this thermal oxidation zone 18, at least a portion of the reaction vessel 16 comprises a thermal oxidizer 20. Accordingly, the oxidation effluent may also comprise combustion products.

[0027] As is known in the art, the thermal oxidizer 20 comprises one or more burners 22 that receive a fuel gas stream 24 and a combustion air stream 26 which react within the thermal oxidation zone 18 to generate a flame. The temperature contemplated for the thermal oxidation zone 18 is a temperature sufficient to oxidize PFAS, and may range from 500°C to 2,300°C. Further, the contemplated residence time may be 0.1 to 30 seconds, for example 0.5 to 15 seconds. Again, these are merely contemplated or exemplary values and are not intended to be limiting.

[0028] The feed stream 12 can be injected into the thermal oxidation zone 18. One or more injection nozzles 28 can be provided in the reaction vessel 16 to inject the feed stream 12 into the thermal oxidation zone 18. The feed stream 12 can be sprayed before entering the reaction vessel 16. For example, the feed stream 12 may be sprayed using a spray fluid 30, such as air, and then the spray fluid and liquid PFAS (sprayed) may be injected into the thermal oxidation zone 18. Alternatively, the feed stream 12 may be sprayed with a mechanical sprayer, and therefore a separate spray fluid 30 may not be required to spray the feed stream 12.

[0029] According to the process of the present invention, at least 90% by weight, or 90-99.999% by weight, or 90-99.9999% by weight of the PFAS from the supply stream 12 is converted to anionic fluoride species in the oxidation zone 14. In some embodiments, 100% by weight of the PFAS is converted to anionic fluoride species in the oxidation zone 14.

[0030] A treatment zone 40 is used to remove any undesirable or harmful components from the oxidation zone effluent 32. However, prior to the treatment zone 40, the oxidation zone effluent 32 may be cooled in a thermal reduction zone 34 or a cooling zone, resulting in a temperature reduction of at least 5% of the oxidation zone effluent 32.

[0031] The heat reduction zone 34 may include a heat exchange zone having a heat exchanger configured to transfer heat from the oxidation zone effluent 32 to the heat exchange fluid. The heat exchanger may be located inside or outside the reactor 16.

[0032] Additionally, or alternatively, the thermal reduction zone 34 may include a quenching zone 36, which may be part of the reaction vessel 16 within the oxidation zone 14. The quenching zone 36 receives a quenching fluid 38, which can be injected into the quenching zone. The quenching fluid 38 may be water, air, or a combination thereof.

[0033] In some embodiments, sensors (not shown) or other monitoring devices can be used to measure the temperature of the oxidation zone effluent 32 at various points (i.e., upstream and / or downstream of the heat reduction zone 34). The obtained or measured temperatures may be compared to a predetermined temperature or other setpoint, and the flow of the cooling fluid (i.e., heat exchange fluid and / or quenching fluid 38) may be adjusted in accordance with the comparison to increase or decrease the temperature of the oxidation zone effluent 32.

[0034] With or without thermal reduction, the oxidation zone effluent 32 is sent to the treatment zone 40 to reduce and / or remove any undesirable or harmful compounds. The treatment zone 40 may include one or more treatment devices 42. As will be described in more detail below, the treatment devices 42 may have a dry adsorbent injection zone, a wet scrubber zone, a carbon bed, a selective catalytic reduction zone, and / or an ion exchange zone. After passing through one or more treatment devices 42 in the treatment zone 40, the treated oxidation zone effluent 44 may be released into the atmosphere. Specific embodiments are described with the understanding that the specific treatment devices 42 included in the treatment zone, and their order, are merely examples, and that those skilled in the art will understand that any number and any order of treatment devices 42 may be combined.

[0035] Referring to Figure 2, the apparatus 200 for converting PFAS according to the present invention may include a processing zone comprising a thermal oxidation zone or section 295, a heat exchanger 320, and a wet scrubber zone 340 for removing anionic fluoride species contaminants from the oxidation effluent. The wet scrubber zone 340 reduces the possibility of light fluorinated carbon and hydrofluorocarbons or other components being released from the oxidation of PFAS. In addition, the wet scrubber zone 340 neutralizes the hydrogen fluoride produced in the oxidation.

[0036] The apparatus 200 receives a feed stream 210, which may be from the PFAS concentration tank 205, but may not be required. In various embodiments, the feed stream 210 is a feed stream containing PFAS in liquid form, either liquid-phase PFAS or dissolved solid-phase PFAS. The feed stream 210 is intended to contain about 0.01% by weight of PFAS, or about 10% by weight of PFAS. However, these amounts are merely illustrative and not intended to be limiting. Furthermore, "about" means including + / - 10% of the stated amounts.

[0037] The thermal oxidation zone 295 includes one or more injection nozzles, such as a combustion air injection nozzle 235, a fuel gas injection nozzle 220, a PFAS waste flow injection nozzle 240, a spray fluid injection nozzle, and heat exchange fluid and / or quenching fluid injection nozzles 230, 260, and 290.

[0038] The supply flow 210 is delivered through the PFAS waste flow injection nozzle 240 to a thermal oxidation zone 295 which includes at least one reaction vessel 270. In the thermal oxidation zone 295, the PFAS is oxidized to anionic fluoride species, among other components. In a preferred embodiment, the thermal oxidation zone 295 includes a thermal oxidation apparatus 275. Thus, the oxidation zone effluent 310 may also include combustion products.

[0039] The supply stream 210 can be injected into the thermal oxidation apparatus 275. Before entering the thermal oxidation apparatus 275, the supply stream 210 may be sprayed. For example, the supply stream 210 may be sprayed using a spray fluid 250, such as air, and then the spray fluid and liquid PFAS (to be sprayed) may be injected into the thermal oxidation apparatus 275. Alternatively, the supply stream 210 may be sprayed with a mechanical sprayer, and therefore a separate spray fluid 250 may not be required to spray the supply stream 210.

[0040] As is well known, the thermal oxidation apparatus 275 includes one or more burners 245 that receive a fuel gas flow 215 through a fuel gas injection nozzle 220 and a combustion air flow 225 through a combustion air injection nozzle 235 (from a combustion air blower 233), which react within the thermal oxidation burner to produce a flame. The temperature intended for the thermal oxidation apparatus 275 is a temperature sufficient to oxidize the PFAS and may be between 500°C and about 2,300°C. Furthermore, the intended residence time may be between 0.1 and 30 seconds, for example between 0.5 and 15 seconds. Again, these are merely intended or exemplary values ​​and are not intended to be limiting.

[0041] According to the process of the present invention, at least 90% by weight, or 90-99.999% by weight, or 90-99.9999% by weight of PFAS from the supply flow 210 is converted to fluoride species in the thermal oxidation zone 295. To reduce the concentration of fluoride species, the oxidation zone effluent 310 passes through a wet scrubber zone 340, and the oxidation zone effluent 310 may be cooled in the thermal reduction zone 305 or a cooling zone, thereby reducing the temperature of the oxidation zone effluent 310.

[0042] Additionally, or alternatively, the thermal reduction zone 305 may include a quenching zone 300, which may be part of a thermal oxidation apparatus 275 within the thermal oxidation zone 295. The quenching zone 300 receives the quenching fluid 285 from a quenching fluid blower 280 (which may be a pump if the quenching fluid 285 is a liquid). The quenching fluid 285 may be water, air, or a combination thereof.

[0043] Additionally, or alternatively, a heat exchange zone having a heat exchanger 320 may be provided to transfer heat from the oxidation zone outflow 310 using a heat exchange fluid. The heat exchanger 320 may be located within or outside the thermal oxidation zone 295.

[0044] The oxidation zone effluent 310 can enter a heat exchanger 320, where it is cooled by a heat exchange fluid 315, which may be boiler feedwater, combustion air, or oil feed, forming a heated flow 325. If the heated flow 325 is boiler feedwater, it can be sent to a heat recovery steam generator (HRSG) saturated flow unit. If the heated flow 325 is oil feed, it can be sent to the high-temperature oil system of the main process unit. Alternatively, all or part of the heated flow 325 can be sent to other areas of the plant as needed.

[0045] In some embodiments, sensors (not shown) or other monitoring devices can be used to measure the temperature of the oxidation zone effluent 310 and / or cooled oxidation zone effluent 330 at various points (i.e., upstream of the heat reduction zone 305 and / or downstream of the heat reduction zone 305 and / or downstream of the heat exchanger 320). The obtained or measured temperatures may be compared to a predetermined temperature or setpoint, and the flow of the cooling fluid (i.e., the heat exchange fluid 315 and / or quenching fluid 285) may be adjusted in accordance with the comparison to increase or decrease the temperature of the oxidation zone effluent 310 or cooled oxidation zone effluent 330.

[0046] The cooled oxidation zone effluent 330 is sent to a wet scrubbing zone 340 to minimize the release of light fluorinated hydrocarbons. The temperature of the oxidation zone effluent 330 is reduced to the saturation temperature using an aqueous flow 555. The aqueous caustic flow 355 can be introduced into the wet scrubbing zone 340 near the top of the tower, so that the caustic flow flows downward and comes into contact with the cooled oxidation zone effluent 330 flowing upward.

[0047] The inlet temperature of the wet scrubber zone 340 is typically in the range of 45 to 150°C at pressures of -12 kPa(g) to 50 kPa(g). The outlet temperature of the wet scrubber zone 340 is typically in the range of 45 to 75°C at pressures of -15 kPa(g) to 50 kPa(g). The operating parameters of the wet scrubber zone 340 are merely intended or illustrative values ​​and are not intended to be limiting.

[0048] Aqueous caustic flow 355 may contain compounds having sodium, calcium, potassium, magnesium, or any combination thereof, such as NaHCO3, NaOH, KOH, K2CO3, CaOH, NaHCO3·Na2CO3·2(H2O), Na2CO3·2Na2CO3·3(H2O), CaCO3, Ca(HCO3)2, Ca(OH)2, Mg(OH)2, CaSO4·2(H2O), CaO, CaCO3·MgCO3, etc. The reactions occurring in the wet scrubber zone 340 may result in the formation and / or conversion of fluoride components, some of which are not limited to H2O, CaCl2, CaF, CaF2, CaCO3, Na2CO3, NaCl, CO2, Na2NO3, NaCl, NaF, K2CO3, KNO3, KCl, KF, MgCl2, MgCO3, Mg(NO3)2, etc.

[0049] The effluent from the wet scrubber zone 340 can be separated into various flows. For example, the vent gas 345 from the wet scrubber zone 340 has reduced levels of anionic fluoride species compared to the cooled oxidation zone effluent 330. The vent gas 345 can be discharged into the atmosphere from the stack within the wet scrubber zone 340. One or more liquid flows 350, 365 can be generated, which may be an aqueous flow 350 released into the environment, or a recirculating flow 365 that can be returned to the wet scrubber zone 340.

[0050] The carbon bed 360 and / or ion exchange zone 460 are intended to be provided before the aqueous flow 350 or vent gas flow 345 is released. As is known, the carbon bed 360 includes materials such as activated carbon, mesh-like glassy carbon foam, carbon aerogel, carbon paper sheets, carbon fibers or carbon fiber-containing composites, carbon fiber aerogel, graphene, graphene aerogel, graphene oxide media, additive printed carbon, additive printed graphene, graphitized media, ionized carbon / non-carbon and magnetized carbon / non-carbon media, and charged carbon media. These materials adsorb various compounds such as furan and dioxins.

[0051] Similarly, the ion exchange zone 460 contains a medium, typically a resin, that selectively removes ions from the flow. The material within the ion exchange zone 460 may be selected for PFAS and other fluorinated species. This material should be resistant to NaCl and NaOH, as well as to dissolved gases.

[0052] Furthermore, the sensor 700 can be used to obtain measurements that can be used to determine the fluorine concentration. For example, the sensor 700 can directly measure the fluorine concentration in each flow or container. Alternatively, the sensor 700 can measure some other attribute, state, or parameter of the flow that can be used to determine the fluorine concentration, for example, using a lookup table. The determined fluorine concentration can be monitored and used to ensure that the fluorine level is suitable for the release of each flow. Therefore, it should be understood that the illustrated location of the sensor 700 is merely illustrative and not limiting. Furthermore, based on the fluorine concentration, the controller (not shown) can send signals to other devices to adjust various processing conditions such as flow rate and temperature, thereby altering the process in an attempt to adjust the fluorine level of each flow.

[0053] Referring to Figure 3, the apparatus 400 includes a processing zone comprising a dry adsorbent injection zone 545 and a selective catalytic reduction zone 361. Parts of the apparatus 400 that are the same as or similar to those of the apparatus 200 shown in Figure 2 have the same reference numerals, and their descriptions are incorporated herein by reference.

[0054] In the apparatus shown in Figure 3, the cooled oxidative effluent 330 is mixed with a reaction mixture that may include fresh reactants 535 and recycled reactants 575. Within the dry adsorbent injection zone 545, the reactants react with various fluoride species, dioxins, and furans in the cooled oxidative effluent 330.

[0055] The reactants include salts containing sodium, calcium, potassium, magnesium, aluminum, silicon, or any combination thereof in solution or mixture. For example, the reactants may include one or more of the following: H2O, CaCl2, CaF, CaF2, CaCO3, Na2CO3, NaCl, CO2, Na2NO3, NaCl, NaF, K2CO3, KNO3, KCl, KF, MgCl2, MgCO3, Mg(NO3)2, NaHCO3·Na2CO3·2(H2O), Na2CO3·2Na2CO3·3(H2O), CaCO3, Ca(HCO3)2, Ca(OH)2, Mg(OH)2, CaO, CaCO3·MgCO3, (Ca(OH)2·(Mg(OH)2).

[0056] The inlet temperature of the dry adsorbent injection zone 545 is typically in the range of 200 to 600°C at a pressure of -3 kPa(g) to 50 kPa(g). The outlet temperature of the dry adsorbent injection zone 545 is typically in the range of 150 to 600°C at a pressure of -5 kPa(g) to 50 kPa(g). The operating parameters of the dry adsorbent injection zone 545 are merely intended or illustrative values ​​and are not intended to be limiting.

[0057] The treated effluent 550 has a reduced level of fluoride species compared to the cooled oxidized effluent 330. The treated effluent 550 may be combined with a quenching stream 655 containing air and / or water and / or quenched flue gas and / or inert gas, or any mixture thereof.

[0058] The treated effluent 550 contains H2O, CaCl2, CaF, CaF2, CaCO3, Na2CO3, NaCl, CO2, Na2NO3, NaCl, NaF, K2CO3, KNO3, KCl, KF, MgCl2, MgCO3, Mg(NO3)2 , NaHCO3·Na2CO3·2(H2O), Na2CO3·2Na2CO3·3(H2O), CaCO3, Ca(HCO3)2, Ca(OH)2, Mg(OH)2, CaO, CaCO3·MgCO3, (Ca(OH)2·(Mg(OH) 2) The material is then sent to a filtration zone 565 to remove at least one of organic acids and particulate matter. The inlet temperature of the filtration zone 565 is typically in the range of 150 to 600°C at a pressure of -5 kPa(g) to 50 kPa(g). The outlet temperature of the filtration zone 565 is typically in the range of 150 to 600°C at a pressure of -7 kPa(g) to 50 kPa(g). The operating parameters of the filtration zone 565 are merely intended or illustrative values ​​and are not intended to be limiting.

[0059] The filtration zone 565 may include a bag filter and / or a ceramic filter and / or an electrostatic precipitator (ESP) for separating solid particles from the gas portion. An instrument air purge or a high-voltage DC 560 is introduced into the filtration zone 565. In the case of an instrument air purge, residual material is purged from the filter. In the case of a high-voltage flow, the cathode of the ESP is charged. Particulate matter may be removed from the ESP by vibration. H2O, CaCl2, CaF, CaF2, CaCO3, Na2CO3, NaCl, CO2, Na2NO3, NaCl, NaF, K2CO3, KNO3, KCl, KF, MgCl2, MgCO3, Mg (NO3)2, NaHCO3·Na2CO3·2(H2O), Na2CO3·2Na2CO3·3(H2O), CaCO3, Ca(HCO3)2, Ca(OH)2, Mg(OH)2, CaO, CaCO The residual flow 570, containing at least one of 3·MgCO3, (Ca(OH)2·(Mg(OH)2), organic acids, and particulate matter, exits the filtration zone 565. All or part of the residual flow 570 can be used in the recycled reactant 575 to increase the conversion rate of the reactants (i.e., from 85% to 98% by weight). The vent gas flow 580 can be discharged into the atmosphere from the stack within the filtration zone 565.

[0060] However, it is also conceivable to reduce or remove nitrogen oxides in the vent gas flow 580 by providing a selective catalytic reaction zone 361. More specifically, it is known that some PFAS contain nitrogen components, or that PFAS-containing feedstocks may contain co-contaminants such as amines, ammonia, or nitrogen oxides. Examples of quaternary ammonium include fluorinated amine oxide surfactants, PFOAAmS, PFOSAmS, PFOAB, PFOSB, and PFOSAm.

[0061] The vent gas stream 580 may also be sent to the reactor in the selective catalytic reaction zone 361, where nitrogen oxides (NOX) exiting the filtration zone 565 are reacted. The selective catalytic reaction zone 361 provides an SCR reactor outflow stream 363 with reduced levels of nitrogen oxides compared to the vent gas stream 580.

[0062] The reactor in the selective catalytic reaction zone 361 may use any suitable SCR catalyst, which may include, but is not limited to, ceramic support materials such as titanium oxide having active catalytic components such as base metal oxides including TiO2, WO3, and V2O5, or activated carbon-based catalysts. The ammonia and / or urea stream 367 may also be introduced into the reactor in the selective catalytic reaction zone 361, where the ammonia and / or urea stream 367 reacts with NOx present in the vent gas stream 580. The reactor inlet temperature in the selective catalytic reaction zone 361 is typically in the range of 150°C to 300°C at a pressure of -8 kPa(g) to 50 kPa(g). The reactor outlet temperature in the selective catalytic reaction zone 361 is typically in the range of 150°C to 350°C at a pressure of -9 kPa(g) to 50 kPa(g).

[0063] Referring to Figure 4, the apparatus 600 is shown, with processing zones including a dry adsorbent injection zone 545, a filtration zone 565, and a wet scrubber zone 340. Although not shown in the figures, the apparatus 600 is intended to also include a selective catalytic reaction zone 361 (see Figure 3), preferably between the filtration zone 565 and the wet scrubber zone 340. Thus, parts of the apparatus 600 that are the same or similar as those of the apparatus 200 shown in Figure 2 and the apparatus 400 shown in Figure 3 have the same reference numerals, and descriptions thereof are incorporated herein by reference.

[0064] In Figure 4, the vent gas flow 580 is sent to the wet scrubber zone 340 and processed as described above. The aqueous recirculated flows 350, 805 can be returned to the wet scrubber zone 340. Furthermore, it may be recirculated to the thermal oxidation zone 295, for example, by mixing with the supply flow 210 or by being used as a quenching fluid in the quenching zone 300 of the thermal oxidation zone 295. Furthermore, the aqueous recirculated flows 350, 805 are intended to be used as a heat exchange fluid 315 for the heat exchanger 320 before being used as a quenching fluid.

[0065] Furthermore, Figure 4 shows a carbon bed 360 that can be used to remove dioxins and / or furans from the vent gas flow 345 from the wet scrubber zone 340. Finally, the aqueous recirculation flow 350 may be sent to the carbon bed 360 and / or the ion exchange zone 460 before being sent to the thermal oxidation zone 295. In this case as well, the sensor 700 can be used to obtain measurements that can be used to obtain the fluorine level in the aqueous recirculation flow 805.

[0066] The systems and devices described herein may include a controller or computing device comprising a processing unit and a memory storing computer-executable instructions for performing the processes described herein. The processing unit may include any suitable device configured to perform a series of steps to implement the method, such that when instructions are executed by the computing device or other programmable device, the device performs the functions / operations / steps specified in the method described herein. The processing unit may include, for example, any type of general-purpose microprocessor or microcontroller, a Digital Signal Processing (DSP) processor, a Central Processing Unit (CPU), an integrated circuit, a Field Programmable Gate Array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0067] Memory may be any suitable known or other machine-readable storage medium. Memory may comprise non-temporary computer-readable storage media, such as, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Memory may include any suitable combination of any type of computer memory located either inside or outside a device, such as Random-Access Memory (RAM), Read-Only Memory (ROM), Compact Disc Read-Only Memory (CDROM), Electro-Optical Memory, Magneto-Optical Memory, Erasable Programmable Read-Only Memory (EPROM), and Electrically-Erasable Programmable Read-Only Memory (EEPROM), and Ferroelectric RAM (FRAM). Memory may include any storage means (e.g., devices) suitable for retrieving computer-executable instructions that can be executed by a processing unit.

[0068] The methods and systems described herein may be implemented in a high-level procedural language, an object-oriented programming language, a scripting language, or a combination thereof, to communicate with or assist the operation of a controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly language or machine code. The language may be a compiled language or an interpreted language. Program code for implementing the methods and systems described herein may be stored on a storage medium or device, such as a ROM, magnetic disk, optical disk, flash drive, or any other suitable storage medium or device. The program code may be readable by a general-purpose or special-purpose programmable computer for configuring and operating a computer when the storage medium or device is read by the computer in order to perform the procedures described herein.

[0069] Computer executable instructions can take many forms, including modules that are executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, and data structures that perform specific tasks or implement specific abstract data types. Typically, the functions of modules may be combined or distributed as desired in various embodiments.

[0070] The system and devices and their components may communicate via any of the various network protocols such as TCP / IP, Ethernet®, FTP, and HTTP, and / or via various wireless communication technologies such as GSM®, CDMA, Wi-Fi, and WiMAX, and it will be understood that the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

[0071] Any of the lines, conduits, units, devices, containers, surrounding environments, zones, or similar entities described above may comprise one or more monitoring components, including sensors, measuring devices, data acquisition devices, or data transmission devices. Signals, process or state measurements, and data from the monitoring components can be used to monitor conditions within, around, and on process equipment. Signals, measurements, and / or data generated or recorded by the monitoring components may be collected, processed, and / or transmitted via one or more networks or connections, which may be private or public, general or specific, direct or indirect, wired or wireless, encrypted or unencrypted, and / or a combination thereof. This specification is not intended to limit us in this respect.

[0072] Signals, measurements, and / or data generated or recorded by the monitoring components may be transmitted to one or more computing devices or systems. A computing device or system may include at least one processor and memory for storing computer-readable instructions that, when executed by at least one processor, cause one or more computing devices to perform a process that may include one or more steps.

[0073] For example, one or more computing devices may be configured to receive data from one or more monitoring components relating to at least one component of equipment associated with a process. One or more computing devices or systems may be configured to analyze the data. Based on the analysis of the data, one or more computing devices or systems may be configured to determine one or more recommended adjustments to one or more parameters of one or more processes described herein. One or more computing devices or systems may be configured to transmit encrypted or unencrypted data containing one or more recommended adjustments to one or more parameters of one or more processes described herein.

[0074] It should be recognized and understood by those skilled in the art that various other components, such as valves, pumps, filters, and coolers, are not shown in the drawings because their details are well within the scope of knowledge of those skilled in the art, and their description is not essential for the practice or understanding of embodiments of the present invention.

[0075] Specific Embodiments The following will be explained in conjunction with specific embodiments, but it should be understood that this explanation is intended to illustrate the scope of the preceding explanation and the attached claims, and is not intended to limit them.

[0076] A first embodiment of the present invention is a process for converting polyfluoroalkyl and perfluoroalkyl substances (PFAS), comprising: oxidizing a feed stream containing liquid PFAS in an oxidation zone to provide an oxidized effluent containing a reduced amount of liquid PFAS compared to the feed stream; and treating the oxidized effluent in a treatment zone to provide a treated effluent, wherein the treatment zone comprises a dry adsorbent injection zone, a selective catalytic reaction zone, a wet scrubber zone, a carbon bed, an ion exchange zone, or any combination thereof. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, in which 90 to 99.9999% of the PFAS in the feed stream is thermally oxidized in a thermal oxidation zone. Another embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, in which the oxidation is carried out at a temperature of 500°C to 2,300°C. One embodiment of the present invention is any or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the residence time of the PFAS in the thermal oxidation zone is 0.1 to 30 seconds. One embodiment of the present invention is any or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further comprising cooling the oxidized effluent in a thermal reduction zone before processing in the treatment zone. One embodiment of the present invention is any or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the treatment zone includes a dry adsorbent injection zone, and the process further comprises mixing reactants with the oxidized effluent to provide a treated effluent, wherein the reactants include salts having sodium, calcium, potassium, magnesium, aluminum, silicon or any combination thereof in a solution or mixture. One embodiment of the present invention is any or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein in the dry adsorbent injection zone, the reactants include a mixture of fresh reactants and recycled reactants.One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the process further includes quenching the treated effluent from the processing zone. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the dry adsorbent injection zone includes a filtration zone configured to separate the treated effluent and provide residual effluent and vent gas flow. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further includes recirculating the residual effluent to the dry adsorbent injection zone as at least a portion of the reactants. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the processing zone includes a selective catalytic reaction zone, the selective catalytic reaction zone receives vent gas flow from the filtration zone. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the processing zone includes a wet scrubber zone, and the process further comprises mixing an aqueous caustic flow with the oxidized effluent to provide a treated effluent. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the aqueous caustic flow includes sodium, calcium, potassium, magnesium, or any combination thereof. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further comprises separating the treated effluent into a liquid flow and a vent gas flow. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, wherein the liquid flow is mixed with the feed flow before introducing the feed flow into the thermal oxidation zone, or the liquid flow is sent to the thermal oxidation zone as a quenched fluid, or both.One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further comprising the process sending a liquid flow to the carbon bed or ion exchange zone before the liquid flow is mixed with a feed flow or sent as a quenched fluid. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further comprising the process sending a liquid flow to the carbon bed or ion exchange zone before the liquid flow is mixed with a feed flow or sent as a quenched fluid. One embodiment of the present invention is one or all of the earlier embodiments in this paragraph, including the first embodiment of this paragraph, further comprising the process sending a liquid flow to the carbon bed or ion exchange zone before the liquid flow is mixed with a feed flow or sent as a quenched fluid.

[0077] Without further detail, it is expected that those skilled in the art will be able to utilize the invention to the fullest extent without departing from the spirit and scope of the invention, and will readily identify its essential characteristics, and will be able to make various changes and modifications to the invention to suit various uses and conditions. Accordingly, the prior preferred specific embodiments should be interpreted as merely illustrative and not to limit the remainder of this disclosure in any way, but are intended to cover various modifications and equivalent configurations that fall within the scope of the appended claims.

[0078] In the above, all temperatures are given in degrees Celsius, and all parts and percentages are based on weight unless otherwise indicated.

[0079] While the above detailed description of the present invention has presented at least one exemplary embodiment, it should be understood that a vast number of variations exist. It should also be understood that the exemplary embodiments (one or more) are merely examples and are not intended in any way to limit the scope, applicability, or configuration of the present invention. Rather, the above detailed description provides useful guidance for carrying out exemplary embodiments of the present invention, and it should be understood that various changes can be made to the arrangement of functions and elements described in the exemplary embodiments without departing from the scope of the present invention as set forth in the appended claims and their legal equivalents.

Claims

1. A process for converting polyfluoroalkyl and perfluoroalkyl substances (PFAS), In the oxidation zone (14, 295), the supply stream (12, 210) containing liquid PFAS is oxidized to provide an oxidized effluent (32, 310) containing a reduced amount of liquid PFAS compared to the supply stream. The process includes processing the oxidized effluent (32, 310) in a processing zone (40) to provide treated effluent (44), wherein the processing zone (40) is Dry adsorbent injection zone (545), Selective catalytic reaction zone (361), Wet scrubber zone (340), Carbon bed (360), Ion exchange zone (460), A process that includes any combination of these.

2. The process according to claim 1, wherein 90 to 99.9999% of the PFAS in the feed stream is thermally oxidized in the oxidation zone (14, 295).

3. The process according to claim 1, wherein the oxidation is carried out at a temperature of 500°C to 2,300°C.

4. The process according to claim 1, wherein the residence time of the PFAS in the oxidation zone is 0.1 to 30 seconds.

5. The process according to claim 1, further comprising cooling the oxidized effluent (32, 310) in the thermal reduction zone (34, 305) before processing in the processing zone (40).

6. The processing zone (40) includes the dry adsorbent injection zone (545), and the process is as follows: The process according to any one of claims 1 to 5, further comprising mixing the reactants (535, 575) with the oxidizing effluent (32, 310) to provide the treated effluent, wherein the reactants comprise a salt having sodium, calcium, potassium, magnesium or any combination thereof in a solution or mixture.

7. The process according to claim 6, wherein the reactants (535, 575) include a mixture of fresh reactants (535) and recycled reactants (575).

8. The processing zone (40) includes the wet scrubber zone (340), and the process is as follows: The process according to any one of claims 1 to 7, further comprising mixing an aqueous caustic flow (355) with the oxidized effluent (32, 310) to provide the treated effluent.

9. The treated effluent is separated into a liquid stream (350, 365, 805) and a vent gas stream (345), The process according to claim 8, further comprising optionally recirculating the liquid flow to the oxidation zone (14, 295).

10. The processing zone (40) includes the carbon bed (360), the ion exchange zone (460), or both, and further includes a sensor (700) configured to provide measurements, wherein the carbon bed (360) or the ion exchange zone (460) receives a portion of the treated effluent (44), and the process is as follows: The fluorine concentration in the liquid portion of the treated effluent is determined from the measured values, To monitor the fluorine concentration in the liquid portion of the treated effluent, The process according to any one of claims 1 to 9, further comprising adjusting the process conditions when the fluorine concentration is outside a predetermined range.

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