Patent Application
20210115353
The present disclosure generally relates to the enrichment of carotenoids in a fatty acid feedstock. More particularly, the disclosure relates to contacting an oil phase containing free fatty acids and carotenoids with a caustic phase within a fiber conduit contactor, thereby effectively partitioning the free fatty acid metal salts and carotenoids out of the oil phase into an aqueous extraction solution, and then neutralizing the extraction solution with an acid to reform and partition the free fatty acids enriched with carotenoids. The net result is a fast, scalable, efficient separation of carotenoids in a free fatty acid matrix derived from crude vegetable oils.
The desire to diversify the value-added co-products from the distillation of corn ethanol cannot be understated. As a byproduct of ethanol distillation, refineries produce oils from the feedstock, e.g., a corn feedstock results in corn oil being produced as a byproduct. The post fermentation oil, also known as distiller's corn oil (“DCO”) when a corn feedstock is employed, is regularly sold at a marginal price as feed for livestock or as feedstock for biodiesel synthesis. However, the DCO can be purified to a food grade oil and sold at a much high price. Among the steps involved in the purification of DCO for human consumption, the removal of free fatty acids (“FFAs”) is paramount. The fermentation process may result in an FFA level over 15% by weight. These FFA levels can be readily reduced to below 1% through the use of fiber conduit contactors, e.g., as described in U.S. Pat. Nos. 7,618,544 and 8,128,825, both of which are incorporated herein in their entireties.
However, it was herein found that upon the extraction of FFAs from DCO using a caustic alcoholic aqueous solution, appreciable co-extraction of the color-bodies present in the crude DCO could be directly visualized as the extracted FFA solution becomes strongly colored. Without being bound by theory, it is believed that the only source for this color should be the carotenoid pigments (also referred to herein as “carotenoids” and including molecules such as α-carotene, β-carotene, canthaxanthin, β-cryptoxanthin, lutein, phytoene and zeaxanthin), which can exist as high as 400 mg/kg (ppm) in DCO. These carotenoids are desirable as natural food pigments and for use in animal feeds. In general, dried distiller's grains (“DDGs”, also a byproduct of ethanol distillation) that are sent to be used as livestock feed are required to have a minimum level of fat (or energy), so the animals will have the appropriate nutrition. The animal feed is regularly enriched with vitamins and minerals to ensure a healthy diet. Furthermore, reports of carotenoid pigments improving desirability in the appearance of egg yolks, meats, and other animal products have created a demand for carotenoid enrichment of livestock feeds.
However, previous attempts to efficiently extract these pigments have been unsuccessful and/or uneconomical. This is due, in part, to the relatively low concentration of carotenoids within DCO. Further, the few reported methods of carotenoid isolation generally involve extraction using a solid phase (e.g., bentonite clay, silica, alumina, polymers, etc.) to remove the carotenoid pigments from DCO. These solid-phase extractants are effective at the decolorization of DCO (i.e., removal of the carotenoid pigments), however, it is challenging to remove the FFAs and carotenoids in one step. As such, there remains a need for a low-cost, efficient process for yielding a neutral oil and a high-concentration carotenoid product.
The present disclosure involves the use of a fiber conduit contactor to reduce the levels of FFAs and carotenoids in a feedstock oil containing FFAs and carotenoids, such as DCO. During the processing of the feedstock oil, FFAs and carotenoids are removed and extracted into a caustic solution having a pH of greater than 7 to yield an extraction solution. The extraction solution is then neutralized with acid to produce an aqueous phase and a fatty acid phase, the fatty acid phase containing the extracted FFAs and carotenoids.
In embodiments of the present disclosure, due to the immiscible nature of the feedstock oil and caustic solution, one method of reacting these components includes creating dispersions of one phase in the other to generate small droplets with a large surface area where mass transfer and reaction can occur. After mixing the reactants, separation of the phases is needed for product purity and quality. However, when using dispersion methods, separation of phases can be difficult and time consuming. Accordingly, in embodiments of the present disclosure, a fiber conduit contactor is employed to provide increased surface area to facilitate reaction between the immiscible liquids while avoiding agitation of the immiscible liquids and the resultant formation of dispersions/emulsions that are difficult to separate.
After the FFAs and carotenoids have been removed into the extraction solution, neutralization (i.e., acidification) may be achieved by simply mixing the extraction solution and an acid or acidifying agent. The acidification results in two, easily separable phases: the aqueous phase and the fatty acid phase. The FFAs in the extraction solution are in the form of fatty acid salts (soap) and are therefore dissolved in the aqueous extraction solution. However, upon acidification, the FFAs become immiscible with the aqueous phase. Further, the carotenoids remain primarily dissolved in the fatty acid phase due to their high lipophilicity.
The isolation of carotenoid pigments through a fiber conduit contactor process as described herein allows for the re-introduction of isolated FFAs with highly-enriched carotenoid content (i.e., the fatty acid phase) to the DDGs or other animal feeds to provide an enriched animal feed. This process increases the value of the DCO (via purification thereof) and the animal feed (through enrichment with carotenoid-containing FFAs), thereby yielding increased profitability. Further, embodiments of the method involve a continuous process with a minimal number of discrete steps.
In addition, the presence of very high concentrations of carotenoids in the fatty acid phase may also allow for existing technologies for carotenoid purification to become economically viable. Such technologies have yet been unprofitable for extracting carotenoids from dilute solutions, such as DCO. An example of a carotenoid extraction process is described in U.S. Patent Application Publication No. 2016/0083766, which is incorporated by reference in its entirety. Moreover, the method of the present disclosure allows for the direct enrichment of a co-product that is already being produced by an ethanol refinery.
The following disclosure provides many different embodiments or examples. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Referring to
Although the fiber conduit contactor shown in
During operation, a constrained phase containing an extractant (also referred to herein as a caustic phase) can be introduced through tube 14 and onto fibers 12. Another liquid (a continuous phase) can be introduced into conduit 10 through inlet pipe 20 and through void spaces between fibers 12. Fibers 12 will be wetted by the constrained phase preferentially to the other liquid. The constrained phase will form a film on fibers 12, and the other liquid will flow therethrough. Due to the relative movement of the other liquid with respect to the constrained phase film on fibers 12, a new interfacial boundary between the other liquid phase and the extractant within the constrained phase is continuously being formed, and as a result, fresh liquid is brought in contact with the extractant, thus causing and accelerating the extraction through unprecedented surface contact between the two reacting immiscible phases.
In embodiments of the present disclosure, the constrained phase is composed of a caustic reagent dissolved in a co-solvent aqueous mixture. The co-solvent mixture is composed of water and one or more alcohols, the composition ratio of which is targeted to affect the selective partitioning of individual carotenoids. The alcohol may include one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, and tert-butanol. In some embodiments, the constrained phase includes alcohol in an amount of at least 5 wt %, at least 10 wt %, at least 15 wt %, at least 20 wt %, at least 25 wt %, at least 30 wt %, at least 35 wt %, at least 40 wt %, at least 45 wt %, at least 50 wt %, at least 55 wt %, at least 60 wt %, at least 65 wt %, at least 70 wt %, at least 75 wt %, at least 80 wt %, at least 85 wt %, at least 90 wt %, at least 95 wt %, or 100 wt %. In some embodiments, the alcohol includes a mixture of ethanol and methanol.
The caustic reagent may include one or more basic compounds. Basic compounds may include, e.g., sodium hydroxide and/or potassium hydroxide. In some embodiments, based on the total weight of the constrained phase, the caustic reagent may constitute 0 to 5 wt %. For example, the caustic reagent may be present in a range defined by any of the following upper and lower limits: at least 0.1 wt %, at least 0.25 wt %, at least 0.5 wt %, at least 0.75 wt %, at least 1.25 wt %, at least 1.5 wt %, at least 1.75 wt %, at least 2 wt %, at least 2.25 wt %, at least 2.5 wt %, at least 2.75 wt %, at least 3 wt %, at least 3.25 wt %, at least 3.5 wt %, at least 3.75 wt %, at least 4 wt %, at least 4.25 wt %, at least 4.5 wt %, at least 4.75 wt %, at most 0.5 wt %, at most 0.75 wt %, at most 1.25 wt %, at most 1.5 wt %, at most 1.75 wt %, at most 2 wt %, at most 2.25 wt %, at most 2.5 wt %, at most 2.75 wt %, at most 3 wt %, at most 3.25 wt %, at most 3.5 wt %, at most 3.75 wt %, at most 4 wt %, at most 4.25 wt %, at most 4.5 wt %, and/or at most 4.75 wt %. The pH of the caustic phase is greater than 7.0, e.g., 7-14, 7-13, 8-12, greater than 7.5, greater than 8.0, greater than 8.5, greater than 9.0, greater than 9.5, greater than 10.0, greater than 10.5, greater than 11.0, greater than 11.5, greater than 12.0, greater than 12.5, greater than 13.0, or greater than 13.5.
The feedstock oil constitutes the continuous phase and is not particularly limited except that the feedstock oil includes FFAs and carotenoids. The feedstock oil may include, e.g., vegetable oils, or a combination of vegetable oils and animal oils. Non-limiting examples of vegetable oils include corn oil, palm oil, cottonseed oil, frying oil, etc. The content of carotenoids in the feedstock oil is not particularly limited. In some embodiments, the feedstock oil has a carotenoid content, based on a total weight of the feedstock oil, of at least 10 ppm, at least 50 ppm, at least 75 ppm, at least 100 ppm, at least 125 ppm, at least 150 ppm, at least 175 ppm, at least 200 ppm, at least 225 ppm, at least 250 ppm, at least 275 ppm, at least 300 ppm, at least 325 ppm, at least 350 ppm, at least 375 ppm, at least 400 ppm, at least 425 ppm, at least 450 ppm, at least 475 ppm, at least 500 ppm, at least 525 ppm, at least 550 ppm, at least 575 ppm, at least 600 ppm, 10-600 ppm, 50-500 ppm, 100-400 ppm, or 200-400 ppm.
In any embodiment, the feedstock oil described above may constitute the constrained phase and the extractant described above may constitute the continuous phase. In one or more embodiments, the feedstock oil and the extractant may be simultaneously introduced into the fiber conduit contactor such that a mixture thereof is constrained to the fibers and a mixture thereof flows between the fibers (i.e., the mixture constitutes both the constrained and continuous phases).
During the reaction between the feedstock oil and the caustic phase, at least some of the carotenoids present in the feedstock oil are removed into the caustic phase (i.e., into the “extraction solution”). In any embodiment, a wide variety of carotenoids may be removed from the feedstock oil by the present method. Without being bound by theory, it is believed that the slightly more polar zeaxanthin and cryptoxanthin derivatives (zeaxanthin, β-cryptoxanthin, canthaxanthin and lutein) are among the most likely carotenoids to be removed into the extraction solution.
In any embodiment, the content of FFAs in the feedstock oil may be, e.g., 20 wt % or less, 15 wt % or less, 12 wt % or less, 10 wt % or less, 9 wt % or less, 8 wt % or less, 7 wt % or less, 6 wt % or less, 5 wt % or less, 4 wt % or less, 3 wt % or less, 2.5 wt % or less, 2 wt % or less, 1.5 wt % or less, 1 wt % or less, or 0.5 wt % or less.
The flow rate of the feedstock oil into the fiber conduit contactor is not particularly limited and, in some embodiments, may be, e.g., 5 to 100 ml/min, 5 to 75 ml/min, 10 to 75 ml/min, 10 to 60 ml/min, 15 to 60 ml/min, 20 to 60 ml/min, 25 to 55 ml/min, or 40 to 50 ml/min. The flow rate of the constrained phase is not particularly limited and, in some embodiments, may be, e.g., 5 to 100 ml/min, 10 to 75 ml/min, 15 to 60 ml/min, 15 to 50 ml/min, 20 to 45 ml/min, 20 to 40 ml/min, 25 to 40 ml/min, or 25 to 35 ml/min. The foregoing values are all based upon a conduit having a cross-sectional area of 20 cm2 and it will be appreciated that these values may be appropriately scaled for a larger or smaller conduit.
The length of the fiber conduit contactor is not particularly limited and may be, e.g., 0.25 to 10 m, 0.5 to 5 m, 0.75 to 3 m, 1 to 2.5, or 1.5 to 2 m. The diameter or width of the fiber conduit contactor is likewise not particularly limited and may be, e.g., 0.5 cm to 3 m, 5 cm to 2.5 m, 10 cm to 2 m, 15 cm to 1.5 m, 20 cm to 1 m, 25 to 75 cm, 30 to 70 cm, 35 to 65 cm, 40 to 60 cm, 45 to 55 cm, or 50 cm.
The fiber materials for the extraction processes described herein may be, but are not limited to, cotton, jute, silk, treated or untreated minerals, metals, metal alloys, treated and untreated carbon allotropes, polymers, polymer blends, polymer composites, nanoparticle reinforced polymer, combinations thereof, and coated fibers thereof for corrosion resistance or chemical activity. In general, the fiber type is selected to match the desired constrained phase. For example, organophilic fibers may be used with a constrained phase that is substantially organic. This arrangement can, for example, be used to extract organic materials from water with organic liquids constrained to the fibers. Suitable treated or untreated minerals include, but are not limited to, glass, alkali resistant glass, E-CR glass, quartz, ceramic, basalt, combinations thereof, and coated fibers thereof for corrosion resistance or chemical activity. Suitable metals include, but are not limited to, iron, steel, stainless steel, nickel, copper, brass, lead, thallium, bismuth, indium, tin, zinc, cobalt, titanium, tungsten, nichrome, zirconium, chromium, vanadium, manganese, molybdenum, cadmium, tantalum, aluminum, anodized aluminum, magnesium, silver, gold, platinum, palladium, iridium, alloys thereof, and coated metals.
Suitable polymers include, but are not limited to, hydrophilic polymers, polar polymers, hydrophilic copolymers, polar copolymers, hydrophobic polymers/copolymers, non-polar polymers/copolymers, and combinations thereof, such as polysaccharides, polypeptides, polyacrylic acid, polyhydroxybutyrate, polymethacrylic acid, functionalized polystyrene (including but not limited to, sulfonated polystyrene and aminated polystyrene), nylon, polybenzimidazole, polyvinylidenedinitrile, polyvinylidene chloride and fluoride, polyphenylene sulfide, polyphenylene sulfone, polyethersulfone, polymelamine, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, co-polyethylene-acrylic acid, polyethylene terephthalate, ethylene-vinyl alcohol copolymers, polyethylene, polychloroethylene, polypropylene, polybutadiene, polystyrene, polyphenol-formaldehyde, polyurea-formaldehyde, polynovolac, polycarbonate, polynorbornene, polyfluoroethylene, polyfluorochloroethylene, polyepoxy, polyepoxyvinylester, polyepoxynovolacvinylester, polyimide, polycyanurates, silicone, liquid crystal polymers, derivatives, composites, nanoparticle reinforced, and the like.
In some cases, fibers can be treated for wetting with preferred phases, to protect from corrosion by the process streams, and/or coated with a functional polymer. For instance, carbon fibers can be oxidized to improve wettability in aqueous streams and polymer fibers can display improved wettability in aqueous streams and/or be protected from corrosion by incorporation of sufficient functionality into the polymer, including but not limited to, hydroxyl, amino, acid, base, enzyme, or ether functionalities. In some cases, the fibers may include a chemical bound (i.e., immobilized) thereon to offer such functionalities. In some embodiments, the fibers may be ion exchange resins, including those suitable for hydroxyl, amino, acid, base or ether functionalities. In other cases, glass and other fibers can be coated with acid, base, or ionic liquid functional polymer. As an example, carbon or cotton fibers coated with an acid resistant polymer may be applicable for processing strong acid solutions. In some cases, fibers may include materials that are catalytic or extractive for particular processes. In some cases, the enzymatic groups may comprise the fibers to aid in particular reactions and/or extractions.
In some embodiments, all the fibers within a conduit contactor may be of the same material (i.e., have same core material and, if applicable, the same coating). In other cases, the fibers within a conduit contactor may include different types of materials. For example, a conduit contactor may include a set of polar fibers and a set of non-polar fibers. Other sets of varying materials for fibers may be considered. As noted above, the configuration of fibers (e.g., shape, size, number of filaments comprising a fiber, symmetry, asymmetry, etc.) within a conduit contactor may be the same or different for the processes described herein. Such variability in configuration may be in addition or alternative to a variation of materials among the fibers. In some embodiments, different types of fibers (i.e., fibers of different configurations and/or materials) may run side by side within a contactor with each set having their own respective inlet and/or outlet. In other cases, the different types of fibers may extend between the same inlet and outlet. In either embodiment the different types of fibers may be individually dispersed in the conduit contactor or, alternatively, each of the different fiber types may be arranged together. In any case, the use of different types of fibers may facilitate multiple separations, extractions, and/or reactions to be performed simultaneously in a conduit contactor from a singular or even a plurality of continuous phase streams. For example, in a case in which a conduit contactor is filled with multiple bundles of respectively different fiber types each connected to its own constrained phase fluid inlet and arranged off-angle, the bundles could be arranged for the continuous phase fluid to pass sequentially over the multiple fiber bundles with different materials extracted by or from each bundle. The fiber diameter is not particularly limited and may be, e.g., 5 to 150 μm, 10 to 100 μm, 12 to 75 μm, 15 to 60 μm, 17 to 50 μm, 20 to 45 μm, 20 to 35 μm, or 20 to 25 μm.
As used herein, the void fraction within the fiber conduit contactor is the total cross-sectional area of the fiber conduit contactor (where the cross section is taken perpendicular to the fiber conduit contactor longitudinal axis) minus the cross-sectional area of all of the fibers combined, divided by the total cross-sectional area. Thus, the void fraction represents the total percentage cross-sectional area available for fluid flow within the fiber conduit contactor. In some embodiments, the void fraction may be greater than 10%, greater than 20%, greater than 30%, greater than 40%, or greater than 50%. In some embodiments, the void fraction may be less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, or less than 20%, less than 15%, less than 10%, or less than 5%. Depending on the size and shape of the fibers, a minimum possible void fraction may be, e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80%.
The temperature of the reaction may be, e.g., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., 90° C., 95° C., 100° C., or greater than 100° C., or may range between any of the foregoing temperature values. In some embodiments, the reaction temperature is limited to the boiling point of the reactants, e.g., an alcohol within the caustic phase. However, operating the fiber conduit contactor at pressure allows the use of reaction temperatures in excess of the boiling points of the reactants and allows reaction temperatures to exceed 100° C. The pressure within the fiber conduit contactor is not particularly limited and may be, e.g., 5 to 75 psi, 10 to 60 psi, 15 to 40 psi, 20 to 30 psi, or 25 psi.
According to the method of the present disclosure, the feedstock oil (oil phase) is reacted with the caustic phase within the fiber conduit contactor to produce a purified oil phase and an extraction solution. The extraction solution includes FFAs and carotenoids removed from the feedstock oil. The purified oil phase and the extraction solution are received in the separator 24 as two distinct phases and separately removed therefrom.
Thereafter, the extraction solution is neutralized with acid in order to separate the FFAs and carotenoids from the other components of the solution (i.e., “the aqueous phase”). In this neutralization/acidification step, the acidifying agent is not particularly limited. In some embodiments, the acidifying agent includes a generally recognized as safe (“GRAS”) acid, such as phosphoric acid, acetic acid, or citric acid. In some embodiments, the acidifying agent may comprise hydrochloric acid or sulfuric acid. In some embodiments, the neutralization step reduces the pH of the aqueous phase to at most 7.0, at most 6.5, at most 6.0, at most 5.5, at most 5.0, at most 4.5, or at most 4.0. In some embodiments, the acidifying agent may be added to the extraction solution in the form of a powder or as an acidic solution. The pH of the acidic solution may be, e.g., less than 7.0, less than 6.5, less than 6.0, less than 5.5, less than 5.0, less than 4.5, less than 4.0, less than 3.0, or less than 2.0.
Once the extraction solution has been neutralized, the aqueous phase and the fatty acid phase form two separate layers. This is because the re-acidified FFAs are immiscible with the aqueous phase. It was herein found that, upon the neutralization/acidification, the carotenoids are relegated almost in entirety to the fatty acid phase. As such, the resultant fatty acid phase contains a high-concentration of carotenoids as compared with that of the original feedstock oil. In some embodiments, this separation may be facilitated by, e.g., centrifuging the mixture.
In some embodiments, the carotenoid content in the fatty acid phase, based on a total weight of the fatty acid phase, may be at least 50 ppm, at least 100 ppm, at least 200 ppm, at least 300 ppm, at least 400 ppm, at least 500 ppm, at least 600 ppm, at least 700 ppm, at least 800 ppm, at least 900 ppm, at least 1,000 ppm, at least 1,250 ppm, at least 1,500 ppm, at least 2,000 ppm, 50-5,000 ppm, 100-2,000 ppm, 200-1,000 ppm, 300-800 ppm, or 400-600 ppm. In some embodiments, a ratio of the carotenoid content in the fatty acid phase to the carotenoid content in the feedstock oil is at least 1.5, at least 2, at least 2.5, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10.
With reference to
A fiber conduit contactor was prepared having a 1″ diameter conduit, packed with 50 μm fibers, and a void fraction of approximately 50%. A constrained phase including water, ethanol and 4 wt % sodium hydroxide was introduced to the fibers at a rate of 75 ml/min. Distiller's corn oil containing 14% FFA by weight was then introduced as a continuous phase at a rate of 125 ml/min. The temperature of the fiber conduit contactor was set at 65° C. and 0 psi pressure was recorded. The resultant two-phase composition is shown in
About 1000 ml of the aqueous phase was added to a separatory funnel with about 20 ml of 85% phosphoric acid and shaken. Within 5 mins, the FFAs plus carotenoids were collected as the top phase 301 and the aqueous phase was collected as the bottom phase 302. The resultant two-phase composition is shown in
A method for producing a carotenoid enriched fatty acid composition has been described herein. The method includes: reacting an oil comprising free fatty acids and carotenoids with a basic solution; withdrawing, separately from the oil, an extraction solution comprising at least a portion of the free fatty acids, at least a portion of the carotenoids, and the basic solution; acidifying the extraction solution to produce an aqueous phase and a fatty acid phase, the fatty acid phase comprising the free fatty acids and the carotenoids of the extraction solution; and separating the fatty acid phase from the aqueous phase.
The method may include any combination of the following features:
A method for producing a carotenoid enriched fatty acid composition using a conduit contactor having a plurality of fibers disposed therein has been described herein. The method includes: introducing a first stream comprising a solvent and a caustic reagent into the conduit contactor proximate the plurality of fibers, wherein a downstream end thereof is disposed proximate a collection vessel, and wherein the first stream has a pH of greater than 7; introducing a second stream containing an oil comprising free fatty acids and carotenoids into the conduit contactor proximate the plurality of fibers; reacting the first and second streams to produce a caustic phase and a purified oil phase, wherein the caustic phase comprises the solvent, the caustic reagent, and at least a portion of the free fatty acids and at least a portion of the carotenoids from the second stream; receiving the caustic phase and the purified oil phase in the collection vessel; withdrawing separately the caustic phase from the collection vessel; acidifying the caustic phase; and separating a fatty acid phase from the acidified caustic phase, wherein the fatty acid phase comprises free fatty acids and carotenoids.
The method may include any combination of the following features:
A system for producing a carotenoid enriched fatty acid composition has been described herein. The system includes: a fiber conduit contactor comprising: a conduit having a hollow interior, a first open end, and a second open end opposite the first open end; a collection vessel in fluid communication with and proximate the second open end; and a plurality of fibers disposed within the conduit; a first stream supply configured to introduce a first stream comprising a basic solution into the conduit and onto the fibers; a second stream supply configured to introduce a second stream comprising an oil comprising free fatty acids and carotenoids into the conduit such that the second stream contacts the first stream; an acidification vessel configured to receive a reaction product of the first and second streams, the reaction product comprising the basic solution, at least a portion of the free fatty acids, and at least a portion of the carotenoids; and a third stream supply configured to introduce a third stream comprising an acid into the acidification vessel.
The system may include any combination of the following features:
It is understood that variations may be made in the foregoing without departing from the scope of the present disclosure. In several example embodiments, the elements and teachings of the various illustrative example embodiments may be combined in whole or in part in some or all of the illustrative example embodiments. In addition, one or more of the elements and teachings of the various illustrative example embodiments may be omitted, at least in part, and/or combined, at least in part, with one or more of the other elements and teachings of the various illustrative embodiments.
This application claims priority to U.S. Provisional Application No. 62/824,785 filed Mar. 27, 2019, the contents of which are herein incorporated in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/025234 | 3/27/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62824785 | Mar 2019 | US |
