Combined cycle system for aluminum energy extraction and method for the manufacturing and processing of impure aluminum energy carriers

Abstract

A combined cycle energy harvesting device and aluminum smelter system. The energy harvesting device consumes an aluminum anode to produce aluminum hydrate. The aluminum smelter converts the aluminum hydrate to an aluminum anode for re-use by the energy harvesting device.

Description

COMBINED CYCLE SYSTEM FOR ALUMINUM ENERGY EXTRACTION ANDMETHOD FOR THE MANUFACTURING AND PROCESSING OF IMPUREALUMINUM ENERGY CARRIERSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and is a non-provisional of, U.S. Patent Application 63 / 647,508 (filed May 14, 2024), the entirety of which is incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] The subject matter disclosed herein relates to aluminum energy carriers and methods for using the same.

[0003] Aluminum energy carriers (e.g. metal air batteries) are used in a variety of applications. Conventionally, high purity (i.e. >99.7% m / m) aluminum is subjected to an oxidation reaction to produce heat, hydrogen gas and electricity. Aluminum hydrates are byproducts of this oxidation. While some attempts have been made to recycle the aluminum hydrate, the process is inefficient due to the stringent requirement that aluminum anodes be formed of high purity aluminum. Additional methods for managing aluminum hydrate waste are therefore desirable.

[0004] The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.SUMMARY

[0005] This disclosure provides a combined cycle energy harvesting device and aluminum smelter system. The energy harvesting device consumes an aluminum anode to produce aluminum hydrate. The aluminum smelter converts the aluminum hydrate to an aluminum anode for re-use by the energy harvesting device.

[0006] In a first embodiment, a combined cycle energy harvesting device and aluminum smelter system is disclosed. The system comprising: an aluminum smelting cell with an alumina inlet and a first gas outlet; an energy harvesting device comprising an aluminum anode, a cathode, an electrolyte, a gas inlet, a second gas outlet, and a spent electrolyte outlet; wherein the gas inlet is connected to the first gas outlet; a precipitation tank fluidly connected to the spent electrolyte outlet, wherein the precipitation tank has an aluminum hydrate outlet; a calciner with an aluminum hydrate inlet, a hydrogen gas inlet, and a combustion source, wherein the hydrogen gas inlet is connected to the second gas outlet, the calciner is connected to the alumina inlet and the aluminum hydrate outlet is connected to the aluminum hydrate inlet.

[0007] In a second embodiment, a combined cycle energy harvesting device and aluminum smelter system is provided. The system comprising: an energy harvesting device comprising an aluminum anode, a cathode and an electrolyte, the energy harvesting device configured to consume the aluminum anode to produce electricity, hydrogen gas, heat and spent electrolyte, the spent electrolyte comprising aluminum hydrate; a precipitation tank configured to receive the spent electrolyte; and a calciner configured to receive the aluminum hydrate and calcinate the aluminum hydrate to alumina; an aluminum smelting cell configured to receive the alumina and electrochemically reduce the alumina to aluminum and transfer the aluminum to the energy harvesting device; wherein: the energy harvesting device is (1) fluidly connected to the precipitation tank to transfer the spent electrolyte thereto (2) connected to the calciner to transfer the hydrogen gas thereto and (3) thermally connected to the calciner to transfer the heat thereto; the precipitation tank is connected to the calciner to transfer the aluminum hydrate to the calciner; the calciner is fluidly connected to the energy harvesting device to transfer the aluminum thereto; the calciner comprises a combustion source configured to ignite the hydrogen and thereby supply heat to effect calcination of the aluminum hydrate.

[0008] In a third embodiment, a method for recycling an aluminum energy carrier is provided. The method comprising: casting a first impure aluminum metal to produce afirst impure aluminum energy carrier that is a powder, a pellet, a foam, or a solid plate; incorporating the impure aluminum energy carrier into an energy harvesting device; operating the energy harvesting device, wherein aluminum hydrate and impurities are produced by an aluminum-oxidation reaction; collecting the aluminum hydrate and impurities from the energy harvesting device; reducing the aluminum hydrate to form a second impure aluminum metal, wherein the first impure aluminum metal and the second impure aluminum sample each consist of 50-99% (m / m) aluminum and a balance of nonaluminum impurities; and casting a second impure aluminum metal to produce a second impure aluminum energy carrier.

[0009] This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughoutthe various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:

[0011] FIG. 1 is a schematic diagram of an example of an aluminum smelting cell.

[0012] FIG. 2 is a flow diagram depicting one method for casting an aluminum energy carrier.

[0013] FIG. 3 is a flow diagram depicting one method for cycling an aluminum energy carrier.

[0014] FIG. 4 is a schematic diagram of one example of an energy generating system.

[0015] FIG. 5 is a schematic diagram of a metal air battery.

[0016] FIG. 6 is a flow diagram of one method of cycling an aluminum energy carrier.

[0017] FIG. 7 is a schematic diagram of a combined cycle energy harvesting device and aluminum smelter system.DETAILED DESCRIPTION OF THE INVENTION

[0018] This disclosure teaches a system and method for the manufacturing, refueling, and processing of impure aluminum and aluminum derivatives in energy carrying applications.

[0019] Referring to FIG. 1, there is provided an aluminum metal manufacturing system 100 comprising an anode 102, a cathode 104, an electrolyte 106 (e.g. a cryolite) and an alumina feedstock 108. The system 100 is for producing an impure aluminum metal 110 energy carrier wherein the impurities of at least 1% (m / m) in the aluminum metal energy carrier are introduced by at least one of the anode 102, the cathode 104, or the electrolyte 106 in the smelting of the aluminum metal 110. The basic and novel characteristic of the aluminum energy carrier is that it functions in an energy harvesting device to provide greater than 500Wh of electrical energy per kilogram of aluminum metal where the aluminum metal has at least 1% (m / m) non-aluminum impurities that are introduced in the smelting process of the aluminum metal.

[0020] Examples of suitable anodes 102 include Pt, Au, Ag, Cu, Pb, Sn, Ni, Co, Fe, Zn, Mn, Ti and Mg, or alloys thereof. Examples of suitable cathodes 104 include carbon / graphite, TiEh, or a combination thereof.

[0021] Referring to FIG. 2, a method 200 is depicted. In step 202 of method 200, an impure aluminum energy carrier from a first source is combined with an impure aluminum energy carrier from a second source to create a blend of impure aluminum energy carriers. For example, spent aluminum anodes from multiple energy harvesting devices or scrap (i.e. secondary) aluminum from multiple sources may be combined to create the blend of impure aluminum energy carriers. The aluminum energy carriers from the first source and the second source need not have the same purity. For example, the aluminum energy carrier from the first source may comprise 99.5% (m / m) aluminum and the balance of non-aluminum materials while the aluminum energy carrier from the second source may comprise 96.0% (m / m) aluminum and the balance of non-aluminum materials.

[0022] In step 204 of method 200, the blend of impure aluminum energy carriers is melted to produce impure molten aluminum. The disclosed impure aluminum materials are designed for use as energy carriers and are not economically valuable for structural aluminum purposes.

[0023] In step 206 of method 200, the impure molten aluminum is cast to produce an impure aluminum energy carrier. Conventional methods for casting molten aluminum into specific forms are well known in the art and include molding, die casting, sand casting, direct chill casting, continuous casting, etc. The impure aluminum energy carrier may be in the form of powder, a pellet, a foam, or a solid plate (e.g. rectangular or discs). The impure aluminum energy carrier consists essentially of aluminum and at least 1% (m / m) non-aluminum impurities (m / m).

[0024] In accordance with one aspect, there is provided an aluminum metal manufacturing process comprising the use of an impure aluminum derivative (including,but not limited to aluminum trihydrate, aluminum monohydrate) for producing impure aluminum metal wherein the impurities of >1% (m / m) in the aluminum metal energy carrier are introduced by the impure aluminum derivative in the production of the aluminum metal.

[0025] FIG. 3 depicts method 300. In step 302 of method 300, an impure aluminum energy carrier is transported to a distal location. For example, the aluminum energy carrier may be cast into the form of an aluminum anode for a metal air battery. The aluminum anode is then transported to a distal location for sequent use in an energy harvesting device.

[0026] In step 304 of method 300, the aluminum energy carrier is incorporated into an energy harvesting device. The energy harvesting device releases electrical, thermal, and / or hydrogen gas from the aluminum energy carrier during an aluminum-water or an aluminum-oxidation reaction. Examples of suitable energy harvesting devices include metal air batteries.

[0027] In step 306, the energy harvesting device is operated and energy is generated during an aluminum-oxidation reaction. This reaction produces aluminum hydrate (e.g. (Al(0H)3, Al(0H)4, A10(0H))) and other impurities that are present in a spent electrolyte. In step 308, the aluminum hydrate and / or the other impurities are collected (e.g. precipitating and / or filtering). In step 310, free water and the calcination products of aluminum hydrate to alumina are removed (e.g. filtering, mechanical separation, sifting, separation by size, weight). In step 312, the resulting waste (e.g. de-watered aluminum hydrate or alumina) is transported from the location where the energy was consumed to a processing plant where the resulting waste is recycled into fresh aluminum energy carrier (e.g. aluminum metal manufacturing system 100).

[0028] In step 314, the resulting material is reduced from aluminum hydrate to impure aluminum metal and the accompanying impurities remain incorporated into the impure aluminum metal. For example, the reduction may be accomplished byelectrochemical reduction in an aluminum smelting cell. As shown in FIG. 3, steps 204 and 206 may thereafter be performed. In this manner, method 300 provides a zero emissions circular method of carrying energy from a point of production to the point of energy demand using an impure aluminum energy carrier.

[0029] Referring to FIG. 4, one example of an energy harvesting system 400 is schematically depicted. The system 400 comprises an air metal battery 402, an air blower 404, and / or an oxygen supply 406 and a carbon dioxide scrubber 408. An electrolyte tank 410 with an electrolyte with a filter 412 is also present. Commonly electrolytes include, for example, aqueous NaOH or KOH solutions. A coolant system with a heat exchanger 414 and pump 416 is provided. An electrolyte pump 418 sends electrolyte through the air metal batter 402 and a gas separator 420. A knockout tank 422 and hydrogen disposal system 424 are also present. FIG. 5 depicts an example of the air metal battery 402 in further detail. The aluminum energy carrier is present as anode 500 and a cathode 502 is proximate to, but spaced from, the anode 500.

[0030] Referring to FIG. 6, a method 600 for recycling an aluminum energy carrier is provided. Method 600 comprises step 602 wherein a first impure aluminum metal is cast to produce a first impure aluminum energy carrier, such as an anode for an metal air battery. The first impure aluminum metal comprises 50-99% (m / m) aluminum and a balance of non-aluminum impurities. In step 604, the first impure aluminum energy carrier is incorporated into an energy harvesting device (e.g. a metal air battery) in a manner similar to that described with regard to step 304 of method 300. In step 606, the energy harvesting device is operated. Step 606 of method 600 is substantially similar to step 306 of method 300 and produces aluminum hydrate along with other impurities. In step 608 of method 600, aluminum hydrate and / or the other impurities are collected. Step 608 of method 600 is substantially similar to step 308 of method 300. In step 610 of method 600, the product (i.e. aluminum hydrate) is reduced to impure aluminum metal that includes the aforementioned impurities. Step 610 of method 600 is substantially similar to step 314 of method 300.

[0031] In some embodiments, the impure aluminum metal from step 610 is melted (see step 614) and subsequently cast (see step 602) into an aluminum energy carrier to form a second impure aluminum energy carrier. In other embodiments, step 612 is performed wherein the impure aluminum metal from step 610 (having a first purity) is combined with a second impure aluminum metal (having a second purity) to create a blend of impure aluminum metal. The first purity and the second purity are both 50-99% (m / m) aluminum and a balance of non-aluminum impurities and the first purity and the second purity are different.

[0032] Referring to FIG. 7, a combined cycle energy harvesting device and aluminum smelter system 700 is disclosed. The system 700 comprises an energy harvesting device 702, an aluminum smelting cell 722, a precipitation tank 714 and a calciner 718. The embodiment of FIG. 7 is a closed-loop system, minimizes waste, and maximizes round trip efficiency by optimizing the energy harvesting device and the smelter conjointly.

[0033] In one embodiment, the energy harvesting device 702 is a metal air battery that consumes an aluminum anode to generate electrical energy 706 to power a device (not shown), heat 708, hydrogen 710 and spent electrolyte 712. The energy harvesting device 702 comprises a gas inlet 702a for receiving gas from the aluminum smelting cell 720 and a gas outlet 702b for providing hydrogen gas to the calciner 718. The energy harvesting device 702 also has a spent electrolyte outlet 702c that is fluidly connected to the precipitation tank 714 such that solids from the spent electrolyte 712 accumulate therein. The spent electrolyte 712 comprises aluminum hydrate 716.

[0034] The precipitation tank 714 comprises an aluminum hydrate outlet 714a that is fluidly connected to an aluminum hydrate inlet 718a of the calciner 718. In this manner, the aluminum hydrate 716 is transferred to the calciner 718.

[0035] The calciner 718 comprises the aluminum hydrate inlet 718a, a combustion source 718b and a hydrogen gas inlet 718c. The alumina hydrate inlet 718a receivesaluminum hydrate from the precipitation tank 714. The hydrogen gas inlet 718c receives hydrogen from the energy harvesting device 702 and provides the hydrogen to the combustion source 718b. The combustion source 718b may be, for example, a flame that ignites the hydrogen to provide heat to the calciner 718 and thereby perform calcination. The calcination produces alumina 720 which is thereafter provided to the aluminum smelting cell 722. The heat 708 may provide further heat to the calciner 718.

[0036] The aluminum smelting cell 722 comprises an alumina inlet 722a for receiving alumina 720 from the calciner 718. The aluminum smelting cell 722 smelts the alumina into aluminum 724. The aluminum smelting cell 722 transfers aluminum 724 to a cooling unit 730 wherein the molten aluminum cools to an acceptable temperature (e.g. cooled to below 450°C). Thereafter the cooled aluminum is transferred to the energy harvesting device 702 for consumption. The aluminum 724 may be transferred as, for example, a solid metal in the form of pellets, plates or as a foam or powder. In some embodiments, the aluminum 724 is transferred to a caster 732 that casts the aluminum into a shape that is suitable for use by the aluminum smelting cell 722.

[0037] The aluminum smelting cell 722 also comprises a first gas outlet 722b for transferring a gas 726 (e.g. steam, CO2, O2) to the energy harvesting device 702. The gas 726 is produced by the aluminum smelting cell 722. For example, an inert anode in the aluminum smelting cell 722 produces O2 while a carbon anode in the aluminum smelting cell 722 produces CO2. By transferring the gas 726 to the energy harvesting device 702, the gas 726 increased the performance of the aluminum-oxidation reaction. In some embodiments, a compressor 728 is present between the aluminum smelting cell 722 and the energy harvesting device 702. The compressor 728 compresses and stores the gas 726 such that the gas 726 is selectively delivered to the energy harvesting device 702.

[0038] In system 700, impurities may be present in the alumina 720 but, at described elsewhere in this specification, the resulting aluminum 724 still functions as an energy source that provides sufficient electricity to operate the energy harvesting device 702. The aluminum 724 is generally impure aluminum that has >1% (m / m) non-aluminumimpurities. Additional aluminum may be added to the energy harvesting device 702 and / or additional alumina may be added to the calciner 718. The efficient use of the heat 708 and the hydrogen 710 minimizes the amount of additional material that is consumed and the use of the gas 726 (e.g. oxygen or carbon dioxide) of the aluminum smelting cell 722 increases the performance of the energy harvesting device 702.

[0039] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

What is claimed is:

1. A combined cycle energy harvesting device and aluminum smelter system, the system comprising: an aluminum smelting cell with an alumina inlet and a first gas outlet; an energy harvesting device comprising an aluminum anode, a cathode, an electrolyte, a gas inlet, a second gas outlet, and a spent electrolyte outlet; wherein the gas inlet is connected to the first gas outlet; a precipitation tank fluidly connected to the spent electrolyte outlet, wherein the precipitation tank has an aluminum hydrate outlet; a calciner with an aluminum hydrate inlet, a hydrogen gas inlet, and a combustion source, wherein the hydrogen gas inlet is connected to the second gas outlet, the calciner is connected to the alumina inlet and the aluminum hydrate outlet is connected to the aluminum hydrate inlet.

2. The system as recited in claim 1, wherein the energy harvesting device is configured to convey hydrogen to the calciner to provide energy for calcination.

3. The system as recited in claim 1, wherein the energy harvesting device is configured to convey heat from the energy harvesting device to the calciner.

4. The system as recited in claim 1, wherein the energy harvesting device is a metalair battery.

5. A combined cycle energy harvesting device and aluminum smelter system, the system comprising: an energy harvesting device comprising an aluminum anode, a cathode and an electrolyte, the energy harvesting device configured to consume the aluminum anode to produce electricity, hydrogen gas, heat and spent electrolyte, the spent electrolyte comprising aluminum hydrate; a precipitation tank configured to receive the spent electrolyte; and a calciner configured to receive the aluminum hydrate and calcinate the aluminum hydrate to alumina;an aluminum smelting cell configured to receive the alumina and electrochemically reduce the alumina to aluminum and transfer the aluminum to the energy harvesting device; wherein: the energy harvesting device is (1) fluidly connected to the precipitation tank to transfer the spent electrolyte thereto (2) connected to the calciner to transfer the hydrogen gas thereto and (3) thermally connected to the calciner to transfer the heat thereto; the precipitation tank is connected to the calciner to transfer the aluminum hydrate to the calciner; the calciner is fluidly connected to the energy harvesting device to transfer the aluminum thereto; the calciner comprises a combustion source configured to ignite the hydrogen and thereby supply heat to effect calcination of the aluminum hydrate.

6. A method for recycling an aluminum energy carrier, the method comprising: casting a first impure aluminum metal to produce a first impure aluminum energy carrier that is a powder, a pellet, a foam, or a solid plate; incorporating the impure aluminum energy carrier into an energy harvesting device; operating the energy harvesting device, wherein aluminum hydrate and impurities are produced by an aluminum-oxidation reaction; collecting the aluminum hydrate and impurities from the energy harvesting device; reducing the aluminum hydrate to form a second impure aluminum metal, wherein the first impure aluminum metal and the second impure aluminum sample each consist of 50-99% (m / m) aluminum and a balance of nonaluminum impurities; andcasting a second impure aluminum metal to produce a second impure aluminum energy carrier.

7. The method as recited in claim 6, wherein the casting step is preceded by: combining an impure aluminum metal with a first purity with an impure aluminum metal with a second purity to produce a blend of impure aluminum metal, wherein the first purity and the second purity are both 50-99% (m / m) aluminum and a balance of non-aluminum impurities and the first purity and the second purity are different; melting the blend of impure aluminum metal to produce the first impure aluminum metal.

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