Thermal recovery from ceramic oxygen concentrator for heating a secondary device

Abstract

Thermal recovery of waste heat output by a ceramic oxygen concentrator for heating a secondary device. A system includes an electrochemical stack comprising a plurality of oxygen concentrator cells, wherein each of the plurality of oxygen concentrator cells comprises: a ceramic electrolyte membrane comprising an oxygen ion conducting material, a cathode layer, and an anode layer. The system includes a heat exchanger that receives an input gas and an oxygen-diminished output gas, wherein the oxygen-diminished output gas is output by the electrochemical stack. The system includes a secondary unit in fluid communication with the heat exchanger, wherein the heat exchanger heats the input gas prior to the input gas being provided to the electrochemical stack, wherein the heat exchanger cools the oxygen-diminished output gas prior to the oxygen-diminished output gas being provided to the secondary unit, and wherein the secondary unit is heated with the oxygen-diminished output gas.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 715,384, filed Nov. 1, 2024, titled “THERMAL-HEAT RECOVERY FROM CERAMIC OXYGEN GENERATOR,” which is incorporated herein by reference in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced provisional application is inconsistent with this application, this application supersedes the above-referenced provisional application.TECHNICAL FIELD

[0002] The disclosure relates generally to efficient use of energy through thermal-heat recovery and relates more particularly to thermal-heat recovery from ceramic devices for concentrating oxygen gas.BACKGROUND

[0003] Many industries and applications benefit from oxygen gas or high purity oxygen gas. Common uses of oxygen gas are in the medical field, in commercial applications, in industrial manufacturing and construction applications, in chemical manufacturing applications, and so forth. High purity oxygen serves a key role in many different industries. However, traditional methods for purifying oxygen are time, resource, and energy intensive. It is therefore desirable to develop systems, methods, and devices for purifying oxygen by way of low cost and low energy means.

[0004] Oxygen is the only element that supports respiration, and it is required to support life and maintain healthy biological processes. Because oxygen is imperative to life and health, separated oxygen and / or high purity oxygen is commonly used in medical applications. For example, medical oxygen is used as a basis for virtually all procedures that involve the use of anesthesia, medical oxygen is typically provided to all patients that are experiencing any respiratory distress, and all patients experiencing low blood oxygen levels. Providing high purity oxygen to a patient can restore the patient's tissue oxygen tension by improving oxygen availability in a wide range of conditions, including cyanosis, shock, sever hemorrhage, carbon monoxide poisoning, major trauma, cardiac arrest, and respiratory arrest. Oxygen can aid in resuscitation of a patient and provides a vital role in sustaining the patient's brain function and tissue health during a time of distress. Hospitals and clinics around the world need a constant ready-to-use supply of purified oxygen gas that can be provided to a patient at any time. Many hospitals, particularly smaller hospitals or remote hospitals, rely on using individual tanks of oxygen gas. This can be extremely expensive and can be a significant financial burden on some medical facilities. In addition, as oxygen in the tanks are consumed, they must be refilled or replaced with pre-filled tanks, and this creates a risk a given medical facility will run out of their stored oxygen supply. This risk is particularly acute during inclement weather or after a local disaster such as a hurricane, earthquake, flooding, mudslide, forest fire, or other disaster when medical oxygen supplies are most needed. Therefore, it is desirable to provide systems, methods, and devices for generating purified oxygen on-site or near the consumer at a lower cost that is sustainable and requires less energy to produce and maintain and is less susceptible to environmental conditions.

[0005] Other important industries that rely on the use of high purity oxygen include a wide range of industrial manufacturing industries such as chemical manufacturing, raw material refinement, and others. Many manufacturing processes benefit from oxygen enrichment. For example, processes involving combustion are greatly improved by lowering the amount of nitrogen gas and increasing the amount of oxygen gas. The combustion efficiencies will increase due to a drop in heat loss as a result of lower mass flow rates. Further for example, processes involving gasification by which coal, or another carbon-based fuel is transformed into a synthesis gas, benefit from oxygen enrichment. Therefore, it is desirable to provide low-cost and high efficiency means for generating copious quantities of oxygen gas for use across many different industries.

[0006] One traditional method of generating oxygen gas is by way of cryogenic air separation. Historically, this method accounts for over 95% of all oxygen production and is performed at a central production plant and then distributed to end users. Cryogenic air separation is used to produce concentrated oxygen or nitrogen in high volumes. Air is commonly made up of oxygen, nitrogen, argon, carbon dioxide, water vapor, and other particles. Cryogenic air separation is based on each of these components having a different boiling point, i.e., when the component transitions from a liquid state to a gaseous state. In cryogenic air separation, the temperature of air is lowered so that nitrogen and oxygen separate based on their different boiling points. This occurs at around −300° F. If high purity oxygen is desired, then further distillation is required. Because the air must be lowered to an extremely cold temperature, cryogenic air separation is expensive in terms of money and energy resources. Further, because cryogenic air separation occurs at large production plants and must then be transported by way of cryogenic vessels or pressurized vessels, this method consumes enormous sums of energy and can be expensive for end users.

[0007] Another method of generating oxygen gas is by way of pressure swing adsorption. Pressure swing adsorption consumes air into a pressurized tank having zeolites. The zeolites, under pressure, create a dipole that allows for the collection of nitrogen and allows oxygen to pass. Pressure swing adsorption is not well suited for processes that require high purity oxygen gas, such as gas that is 95% or more oxygen. In some implementations, multi-stage pressure swing adsorption is capable of generating high purity oxygen, but the cost is tremendously high, and it is not a desirable process to perform. Pressure swing adsorption can be implemented on-site by an end user, but it cannot produce high purity or ultra-high purity oxygen without an enormous increase in cost. This method is typically used for low purity applications with an oxygen concentration of 93% or less.

[0008] In view of the foregoing, disclosed herein are systems, methods, and devices for improved oxygen concentration and pressurization, and further for capturing and reusing waste heat produced by oxygen concentration systems.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Non-limiting and non-exhaustive implementations of the present disclosure are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. Advantages of the present disclosure will become better understood with regard to the following description and accompanying drawings where:

[0010] FIG. 1 is a schematic illustration of a system for thermal heat recovery from devices for oxygen concentration and pressurization;

[0011] FIG. 2 is a schematic illustration of a system for thermal heat recovery from devices for oxygen concentration and pressurization;

[0012] FIG. 3 is a schematic illustration of a system for thermal heat recovery from devices for oxygen concentration and pressurization;

[0013] FIG. 4 is a schematic cross-sectional view of layers and components of two oxygen concentrator cells of an electrochemical stack;

[0014] FIG. 5 is a schematic cross-sectional view of layers, components, and reactions occurring within and surrounding an oxygen concentrator cell of an electrochemical stack;

[0015] FIG. 6 is a schematic illustration of a system for thermal heat recovery from devices for oxygen concentration and pressurization; and

[0016] FIG. 7 is a schematic flow chart diagram of a method for capturing and repurposing heat generated by oxygen concentration system.DETAILED DESCRIPTION

[0017] Described herein are systems, methods, and devices for thermal heat recovery from ceramic oxygen concentrators. Specifically described herein are systems, methods, and devices for efficiently capturing waste heat generated by a ceramic oxygen concentrator, and then repurposing the captured waste heat for other purposes such as, for example, medical sterilizer, heaters, steam generators, water heaters, room heaters, and other systems that utilize warm or hot air.

[0018] The present disclosure extends to systems, methods, and devices for capturing and reusing waste heat that is output by systems and devices for oxygen concentration and pressurization. As described herein, the waste heat may be captured and reused to heat a secondary system, which may include, for example, a dry air sterilizer, dry air fabric heater, steam generator, water heater, room heater, building heater, film shrinker, dryer, process preheater, water purifier, water desalination device, agricultural processor, food processor, snow melter, de-icing device, and so forth.

[0019] There are numerous industries and procedures that benefit from purified oxygen gas. In some instances, it may be beneficial or even necessary to use high purity oxygen gas that has a 95% or greater concentration of oxygen molecules. However, the methods known in the art for generating oxygen gas at any concentration, and particularly at high concentration levels, can be very costly in terms of time, money, and energy resources. Further, such methods are typically implemented at large production plants and then shipped to end users in pressurized vessels or specialized cryogenic transport and containment systems. This causes a supply chain risk that can lead to devastating consequences in certain instances such as a natural disaster where oxygen is necessary for medical needs but cannot be shipped due to infrastructure problems. Disclosed herein are systems, methods, and devices for generating high purity or ultra-high purity oxygen gas. The systems, methods, and devices disclosed herein are cost efficient and energy efficient, can be deployed on-demand, eliminate the need for oxygen gas cylinders or cryogenic containers, eliminate supply chain risks, and can produce ultra-high purity oxygen that far exceeds regulatory purity specifications.

[0020] An embodiment of the disclosure deploys an electrochemical stack including multiple oxygen concentrator cells. Each of the multiple oxygen concentrator cells includes multiple layers, including an anode, a cathode, and a ceramic electrolyte. The oxygen concentrator cells of the electrochemical stack are configured to accept gaseous molecules when air or some other oxygen containing gas is passed through the electrochemical stack. The electrolyte layer within each of the multiple oxygen concentrator cells is configured to accept or draw in oxygen ions while remaining non-permeable to other non-oxygen ions, atoms, or molecules. When an input gas is exposed to an oxygen concentrator cell of the electrochemical stack, oxygen molecules are separated from other components in the input gas, such as argon gas, nitrogen gas, carbon dioxide, and others. The separated oxygen is harnessed and may be stored in a tank or immediately used. The other non-oxygen components may also be harnessed or may be released into the environment. The electrochemical stack disclosed herein may generate high purity or ultra-high purity oxygen using only a fraction of the energy that is required to deploy traditional oxygen purification methods such as cryogenic air separation and / or pressure swing adsorption and / or vacuum swing adsorption and / or water electrolysis.

[0021] In an embodiment, an electrochemical stack is configured to generate extremely high purity oxygen streams in excess of 99.9% purity at very high volumes. The volumetric flow of the electrochemical cell multi-stack system may be equivalent to or superior to the volumetric flow of cryogenic separation systems in some embodiments. The electrochemical stack may be run at elevated temperature with a voltage applied. The electrochemical stack is constructed of a plurality of oxygen concentrator cells that include metals and ceramic oxides. When air (or any oxygen-containing gas) is passed over the electrochemical stack, a voltage is applied that electrolyzes and splits oxygen molecules in stable oxygen gas (O2) and generates two separate negatively charged oxygen ions (2O2−) per oxygen molecule (the negatively charged oxygen ions may be referred to herein as oxygen anions). Oxygen ions can also be extracted from other oxygen containing gases such as water and carbon dioxide. The oxygen ions migrate through the ceramic electrolyte membrane of the oxygen concentrator cells in the electrochemical stack due to an applied EMF (electromotive force). Because the specialized selection of materials in the ceramic membrane do not transport non-oxygen ions, the process only filters oxygen at an exceptionally high purity rate.

[0022] For the purposes of promoting an understanding of the principles in accordance with the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the disclosure as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure claimed.

[0023] Before the structure, systems, and methods for producing an image in a light deficient environment are disclosed and described, it is to be understood that this disclosure is not limited to the particular structures, configurations, process steps, and materials disclosed herein as such structures, configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting since the scope of the disclosure will be limited only by the appended claims and equivalents thereof.

[0024] In describing and claiming the subject matter of the disclosure, the following terminology will be used in accordance with the definitions set out below.

[0025] It must be noted that, as used in this specification and the appended claims, the singular forms “a,”“an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0026] As used herein, the terms “comprising,”“including,”“containing,”“characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps.

[0027] As used herein, the phrase “consisting of” and grammatical equivalents thereof exclude any element or step not specified in the claim.

[0028] As used herein, the phrase “consisting essentially of” and grammatical equivalents thereof limit the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic or characteristics of the claimed disclosure.

[0029] Referring now to the figures, FIG. 1 is a schematic illustration of a system 100 for ceramic oxygen generation and thermal heat recovery. The system 100 includes three major components, including a controller 130 that operates at ambient temperature, a ceramic oxygen concentrator 102 that operates at elevated temperatures, and a secondary unit 120 that utilizes waste heat output by the ceramic oxygen concentrator 102.

[0030] The controller 130 includes at least control systems electronics 132 and power distribution electronics 134. The controller 130 is in electrical communication with one or more components of the ceramic oxygen concentrator 102 and may specifically be in electrical communication with one or more of a blower 106 or heater 112. The controller 130 may additionally be in electronic communication with the secondary unit 120.

[0031] The ceramic oxygen concentrator 104 is fed by input gas 114, which may specifically include ambient air. The input gas 114 may be pulled into the ceramic oxygen concentrator 104 with a blower 106. The process air flow path may be open and unrestricted such that the performance specifications for the blower 106 may be minimal and similar to those of ventilation blowers utilized in residential settings (e.g., from about 0.35 to about 0.55 cubic meters per minute).

[0032] The input gas 114 is drawn into a heat exchanger 110 and heated with a heater 112 prior to being processed through an electrochemical stack 104. The operating temperature for the electrochemical stack 104 may be from about 500° Celsius to about 900° Celsius. In some cases, the system 100 may include a heat exchanger 110 including a dual-purpose heat exchanger that simultaneously preheats the input gas 114 stream while cooling heated processed air prior to venting as oxygen-diminished output gas 116. Thus, the oxygen-diminished elevated-temperature output gas is sent through the heat exchanger 110, partially cooled, and then vented from the ceramic oxygen concentrator 102. This arrangement reduces energy consumption and simplifies venting requirements by reducing the temperature of the exhaust products. The heater 112 may comprise a process air heater that is located in between the heat exchanger 110 and the electrochemical stack 104. The heater 112 provides a significant amount of heating during transient startup and operates under reduced loads in steady-state operation.

[0033] The heat exchanger 110 may include a passive heat exchanger or may include a mechanical device such as a pump, fan, or compressor to feed the input gas 114 and the oxygen-diminished output gas 116 through the heat exchanger 110. The heat exchanger 110 may include a counterflow heat exchanger, and may specifically include a counterflow shell-and-tube heat exchanger, a double-pipe counterflow heat exchanger, a spiral heat exchanger, a tube-in-tube counterflow heat exchanger, a hairpin heat exchanger, a microchannel counterflow heat exchanger, or a counterflow tube bundle. In the heat exchanger 110, the cooler input gas 114 flows counter to the high-temperature oxygen-diminished output gas 116 that has exited the electrochemical stack 104. This causes the cooler input gas 114 to be heated to an elevated temperature prior to passing through the electrochemical stack 104. This further causes the high-temperature oxygen-diminished output gas 116 that has exited the electrochemical stack to be cooled to a lower temperature prior to being provided to the secondary unit 120.

[0034] The electrochemical stack 104 is an ion transport mechanism that extracts oxygen from the input gas 114, outputs purified oxygen gas 108 and adds heat to the input gas 114 (i.e., the ion transport process, which transports oxygen across the ceramic, produces waste heat). The electrochemical stack 104 comprises an impermeable, dense, monolithic ceramic structure. The electrochemical stack 104 comprises ceramic materials capable of transporting oxygen ions when supplied with an electrical potential. These ceramic materials within the electrochemical stack 104 do not conduct electricity (i.e., do not transport electrons), but are capable of transporting oxygen if supplied with an electric potential. The ion transport membranes of the electrochemical stack 104 are made from ion-conducting ceramic oxides, which are insensitive to elevated temperature oxygen service. These ceramic oxide materials can be formed into dense structures, and when constructed into an operational device, may take the shape of a membrane that is gas impermeable. When the ion transport membrane is connected to a “strongback” structure, the ion transport membrane forms a hermetic seal with the input gas 114 on one side and the oxygen-diminished output gas 116 on the other side.

[0035] Gases cannot permeate an ion transport membrane, but oxygen ions can be electrically transported provided they are given a direct current electrical potential. The ion transport membrane material may comprise an oxide lattice structure that has atomic-scale holes. These atomic-scale holes may contain and transport an oxygen ion under an applied electrical potential, as the oxygen ions can migrate through the membrane by moving from one hole to another across the thickness of the membrane.

[0036] The other constituents of air (e.g., nitrogen, argon, carbon dioxide, and excess oxygen) are unaffected by the ion transport membrane of the electrochemical stack 104. Some of the oxygen is electrochemically dissociated into oxygen ions, and the oxygen ions are electrochemically pumped across the ion transport membrane of the electrochemical stack 104. The rate of oxygen ion transport is set by the current passing through the membrane. The current / oxygen flow relationship is linear.

[0037] The system interfaces may be comparable to pressure swing adsorption (PSA) oxygen generation systems. The system 100 may be placed in a vented location and connected to a source of electricity. The system 100 may utilize ambient air, which serves as the source of oxygen and regulates internal temperatures. The input gas 114 may be steady state and continuous, and in some cases, there are no air selector valves and no mechanical movement other than the blower 106.

[0038] The system 100 captures the heated oxygen-diminished output gas 116 and reuses the heat for a secondary unit 120. The oxygen-diminished output gas 116 may comprise a temperature from about 100° to about 500° C. after exiting the heat exchanger 110. This heated oxygen-diminished output gas 116 is captured and provided to the secondary unit 120. In some cases, the system 100 may additionally and optionally include a boost heater 118 to further heat the oxygen-diminished output gas 116 prior to providing the oxygen-diminished output gas 116 to the secondary unit 120.

[0039] The secondary unit 120 may include any device that utilizes or requires heated gas. The secondary unit 120 may include, for example, a dry air sterilizer, dry air fabric heater, steam generator, water heater, room heater, building heater, film shrinker, dryer, process preheater, water purifier, water desalination device, agricultural processor, food processor, snow melter, de-icing device, and so forth. Notably, the oxygen-diminished output gas 116 is sterilized when passing through the ceramic oxygen concentrator 102. The oxygen-diminished output gas 116 may be maintained in a sterilized condition when provided to the secondary unit 120.

[0040] The one or more secondary units 120 utilize the captured heat of the oxygen-diminished output gas 116 and ultimately output warm exhaust 122. The warm exhaust may include oxygen-diminished output gas and may in some cases additionally include ambient air and other gases.

[0041] FIG. 2 is a schematic illustration of a system 200 for ceramic oxygen generation and thermal heat recovery. The system 200 includes the components described and illustrated in connection with FIG. 1. The system 200 additionally includes a thermal enclosure 202, and each of the ceramic oxygen concentrator 102 and the secondary unit 120 is disposed within the thermal enclosure 202. The thermal enclosure 202 comprises insulation to maintain the elevated temperature of the oxygen-diminished output gas 116 and to provide more efficient thermal capture of the oxygen-diminished output gas 116.

[0042] In some cases, as shown in FIG. 2, each of the heat exchanger 110, electrochemical stack 104, heater 112, boost heater 118, and secondary unit 120 may be disposed within the thermal enclosure. This aids in reducing loss of thermal energy prior to providing the oxygen-diminished output gas 116 to the secondary unit 120.

[0043] FIG. 3 is a schematic illustration of a system 300 for two-stage oxygen concentration, purification, and compression, and further for thermal capture of oxygen-diminished output gas. In some cases, it is desirable to implement the two-stage oxygen concentration system 300 illustrated in FIG. 3 to output higher pressure oxygen gas. However, it is not necessary to implement the two-stage system 300, and a singular stage system like the one described in FIGS. 1 and 2 may be implemented to output ultra-high purity oxygen gas.

[0044] The system 300 includes an oxygen concentration and a compression system that includes a first stage oxygen concentrator and a second stage oxygen concentrator. In the example illustrated in FIG. 3, the first stage oxygen concentrator comprises a first-stage electrochemical stack 304, although this is not required. In alternative embodiments, the first stage oxygen concentrator may include any other means of purifying, separating, or concentrating oxygen. Further in the example embodiment illustrated in FIG. 3, the second stage oxygen concentrator includes a second-stage electrochemical stack 306.

[0045] In the example illustrated in FIG. 3, the first stage oxygen concentrator and the second stage oxygen concentrator are disposed within the same housing. In alternative implementations, the first and second stage oxygen concentrators may be disposed within different housings or may be located in different geographic locations.

[0046] The system 300 comprises means for thermal heat capture and reuse in a two-stage oxygen purification system. The system 300 outputs oxygen-diminished output gas 116 that is heated by the first-stage electrochemical stack 304. The oxygen-diminished output gas 116 is captured and provided to a secondary unit 120. In some cases, the oxygen-diminished output gas 116 is further heated by a boost heater 118 prior to being provided to the secondary unit 120.

[0047] The system 300 includes a low-pressure storage vessel 310 and a high-pressure storage vessel 312. The system 300 outputs high purity oxygen, including low-pressure oxygen 308a output by a first stage of the system 300, and high-pressure oxygen 308b output by a second stage of the system 300 (the oxygen gas may generally be referred to as oxygen gas 308 as discussed herein). The “low-pressure” high purity oxygen 308a is still pressurized and is only considered “low-pressure” relative to the high-pressure oxygen 308b output by the second stage of the system 300.

[0048] The low-pressure oxygen 308a is high purity oxygen gas that has been concentrated with the first stage oxygen concentrator of the system 300. The system 300 then further concentrates and further pressurizes the oxygen gas, such that the high-pressure oxygen 308b may have increased purity when compared with the low-pressure oxygen 308a.

[0049] The system 300 begins with a first stage of oxygen concentration and compression. In the example illustrated in FIG. 3, the first stage oxygen concentration is executed with the first electrochemical stack 304, which includes a plurality of electrochemical cells arranged in series as shown in FIG. 3. The first electrochemical stack 304 receives an input gas 114 and outputs the low-pressure oxygen gas 308a. The low-pressure oxygen gas 308a is then carried to the low-pressure storage vessel 310 and is stored therein. The system 300 receives the input gas 114 at a first stage inlet port 316. The first stage inlet port 316 may include a blower (see, e.g., blower 106 at FIG. 1) for pulling or pushing the input gas 114 into the system 300. The input gas 114 is any oxygen-containing gas and may specifically include air.

[0050] After passing through the first stage inlet port 316, the input gas 114 is pushed into a region comprising insulation 320. The input gas 114 may specifically be pushed into an input gas conduit that is disposed within and surrounded by the insulation 320. The input gas 114 is heated as it passes through the insulation 320 and thus creates heated input gas 114. The heated input gas 114 is fed into an oxygen concentration inlet region 322 wherein the heated input gas 114 is taken up by one or more of the series of the first electrochemical stack 304. In the example illustrated in FIG. 3, the heated input gas 114 is continually heated as it passes through the insulation 320 and around the second electrochemical stack 306 prior to being fed into the concentration inlet region 322.

[0051] In the example depicted in FIG. 3, the first electrochemical stack 304 includes a series of eight electrochemical stacks arranged in series. Each of the eight electrochemical stacks comprises a plurality of electrochemical cells, which may alternatively be referred to as oxygen concentrator cells as described herein. The system 300 may include any number of electrochemical stacks. In some cases, the first stage oxygen concentrator will include only one electrochemical stack. The series of the first electrochemical stack 304 retrieves oxygen from the heated input gas 114 and outputs the low-pressure oxygen 308a through a first stage oxygen outlet pipeline 324. As shown in FIG. 3, each of the individual first electrochemical stacks 304 includes a first stage oxygen outlet pipeline 324, and the collection of the first stage oxygen outlet pipelines 324 eventually feed into the low-pressure storage vessel 310. The low-pressure oxygen gas 308a may be retrieved and utilized directly from the low-pressure storage vessel 310 as shown in FIG. 3.

[0052] The system 300 continues with a second stage of oxygen concentration and compression. The second stage is executed by the second electrochemical stack 306, which may include a series of a plurality of electrochemical stacks as shown in FIG. 3. The second electrochemical stack 306 receives the low-pressure oxygen 308a as an input. The low-pressure oxygen 308a is fed to the second electrochemical stack 306 directly from the low-pressure storage vessel 310 as shown in FIG. 3. The second electrochemical stack 306 outputs high-pressure oxygen gas 308b that is then stored in the high-pressure storage vessel 312.

[0053] The second stage oxygen concentrator receives the low-pressure oxygen gas 308a as an input from the low-pressure storage vessel 310 by way of a second stage inlet pipeline 326. The second stage inlet pipeline 326 feeds the low-pressure oxygen 308a through a series of electrochemical stacks making up the second electrochemical stack 306. The second electrochemical stacks 306 are heated by a heating element 328 and surround by a collection region 330 that receives high-pressure oxygen gas 308b output by the series of the second electrochemical stacks 306. The high-pressure oxygen gas 308b is output through a second stage oxygen outlet pipeline 332 that feeds into the high-pressure storage vessel 312.

[0054] Alternatively, the oxygen concentration and compression system 300 may be split into two separate systems and two separate enclosures wherein the first-stage system is located in a first enclosure, and the second-stage system is located in a second enclosure, and the second-stage system may receive oxygen gas 308a from the first-stage system and produce higher concentration and higher-pressure oxygen gas 308b. A two-stage system with two separate enclosures is not shown in FIG. 3.

[0055] The low-pressure storage vessel 310 may be configured with a maximum pressure of about 300 pounds per square inch gauge (psig). The low-pressure storage vessel 310 may be configured with a maximum pressure from about 5 psig to about 150 psig. The high-pressure storage vessel 312 may be configured with a maximum pressure of about 10,000 psig. The high-pressure storage vessel 312 may be configured with a maximum pressure from about 300 psig to about 15,000 psig depending on the implementation. It should be understood that the pressurizations of the low-pressure storage vessel 310 and the high-pressure storage vessel 312 may vary depending on the implementation. As discussed herein, the “low-pressure” high purity oxygen gas 308a is stored at a moderate pressure and is only referred to as “low-pressure” herein because it is output and stored at a lower pressure relative to the high-pressure oxygen gas 308b.

[0056] FIG. 4 is a schematic illustration of a cross-sectional straight-on side view of two adjacent oxygen concentrator cells 402 of an electrochemical stack (see 202) of a stack assembly (see 104). The oxygen concentrator cells 402 serve as a ceramic ion transport membrane that extracts oxygen from an input gas 114 and then transports the oxygen across an impermeable, dense, monolithic ceramic structure.

[0057] Each oxygen concentrator cell 402 includes a cathode, electrolyte 1004, and anode. The oxygen concentrator cells 402 specifically include a cathode secondary layer 408, cathode 410, electrolyte 412, anode 420, anode secondary layer 416, and anode cap 420. The oxygen concentrator cells 402 includes a nonporous edge 418 that extends from the electrolyte 412 to the anode cap 420 to seal the porous anode 420 and porous anode secondary layer 416. The oxygen concentrator cells 402 include the spacer 404, which is sealed to the electrolyte 412 and extends upward to seal the porous cathode 410 and porous cathode secondary layer 408. As shown in FIG. 4, the spacer 404 extends above the surface of the cathode secondary layer 408 and is sealed to the anode cap 420 of an adjacent oxygen concentrator cell 402.

[0058] The spacer 404 provides a gap between two oxygen concentrator cells 402 in the electrochemical stack 202. The gap enables the input gas 114 to enter at the leading edge of an oxygen concentrator cell 402 and further enables the oxygen-diminished output gas 115 to exit at the trailing edge of the oxygen concentrator cell 402. The spacer 404 surrounds an oxygen exhaust port 422 that provides an outlet for purified oxygen gas 108 to exit the stack assembly (see 104).

[0059] The spacer 404 may be co-sintered with the other layers of the oxygen concentrator cell 402, including the cathode secondary layer 408, cathode 410, electrolyte 412, anode 420, anode secondary layer 416, anode cap 420, and nonporous edge 418. In an alternative implementation, the spacer 404 is manufactured separately from the other layers of the oxygen concentrator cell 402, and the spacer 404 is later sealed to the electrolyte 412 and the anode cap 420 of an adjacent oxygen concentrator cell 402.

[0060] There are numerous benefits to the spacer 404 being co-sintered with the remaining layers of the oxygen concentrator cell 402. The spacer 404 provides a gastight seal with the anode cap 420 of an adjacent oxygen concentrator cell 402 located above the spacer 404, and the spacer 404 further provides a gastight seal with the electrolyte 412 of the same oxygen concentrator cell 402. When the spacer 404 is co-sintered with the other layers of the oxygen concentrator cell 402, the gastight seal between the spacer 404 and the electrolyte 412 is structurally more rigid and provides an improved nonporous seal. There are numerous challenges associated with co-sintering the spacer 404 with the other layers of the oxygen concentrator cell 402. One such challenge is the sintering process may cause the spacer 404 to curl and separate from the remaining layers due to differences in thickness, shape, and materials.

[0061] The cathode secondary layer 408 is a porous material and is configured to receive the input gas 114. The input gas 114 is passed over the electrochemical stack 202 and over each oxygen concentrator cell 402 within the electrochemical stack 202. The input gas 114 may be blown into the electrochemical stack 202. Molecular diffusion causes the input gas 114 to enter the cathode secondary layer 408. The cathode 410 is a porous material and is configured to receive the input gas 114 after the input gas 114 has passed through the cathode secondary layer 408. Molecular diffusion causes the input gas 114 to enter the cathode 410. The cathode 410 makes direct contact with the electrolyte 412.

[0062] The electrolyte 412 is a specialized ceramic material that receives oxygen ions. The electrolyte 412 is nonporous when compared with the cathode secondary layer 408, cathode 410, anode 420, or anode secondary layer 416. The electrolyte 412 may be referred to as “nonporous,” but it should be appreciated the electrolyte 412 may still have some unavoidable porosity due to its inherent ceramic properties. The electrolyte 412 may specifically be described as having no through-porosity such that the electrolyte 412 does not permit molecular diffusion across the electrolyte 412 layer but will permit diffusion of oxygen ions across the electrolyte 412 layer. There are oxygen atom deficiencies throughout the crystal structure of the electrolyte 412. The electrolyte 412 will not permit diffusion of ions other than oxygen ions (O2−). The input gas 114 located within the cathode 410 may include oxygen molecules (O2). A voltage is applied to the electrochemical stack 202 that enables a reduction reaction to occur to the oxygen molecules (O2) at the surface of the electrolyte 412. The reduction reaction follows Equation 1, below.O2+4⁢e-→2⁢O2-Equation⁢ 1

[0063] The reduction of the oxygen molecules (see Equation 1) occurs at the surface of the electrolyte 412, and it may also occur in the cathode 410 in close proximity to the electrolyte 412. The reduction of one oxygen molecule results in two oxygen ions. The two oxygen ions are accepted by the electrolyte 412 to fill oxygen deficiencies within the crystal lattice structure of the electrolyte 412 ceramic material. Oxygen ions travel within the crystal lattice structure of the electrolyte 412, and possibly along grain boundaries of electrolyte 412, and are eventually oxidized at the surface of the anode 420 according to Equation 2, below.2⁢O2-→O2+4⁢e-Equation⁢ 2

[0064] The anode 420 is a porous material that accepts the oxygen molecules (O2). During operation, a voltage, or EMF is applied to the electrochemical stack 202. Because of the EMF, the oxygen molecules created according to Equation 2 near the anode-side of the electrolyte 412 may be consumed by the anode 420 even when the oxygen molecules are travelling from the electrolyte 412 to the anode 420 against a concentration gradient. Because the electrolyte 412 lacks through-porosity and will only accept oxygen ions, the anode 420 and anode secondary layer 416 may only consume pure oxygen. The electrolyte 412 is such that there are no non-oxygen molecules or ions traveling through the electrolyte 412 crystal lattice structure that may eventually reach the surface of the anode 420. The anode secondary layer 416 is a porous material that holds the purified oxygen gas 108 that is received by the anode 420.

[0065] The anode cap 420 is a nonporous material that prevents the purified oxygen gas 108 from traveling beyond the anode secondary layer 416. There is a hole running through each of the layers of the oxygen concentrator cell 402 such that the purified oxygen gas 108 may only travel through the oxygen exhaust port 422 and be harvested by the system.

[0066] The spacer 404 extends to the electrolyte 412 to prevent contamination of the purified oxygen gas 108 that is traveling in the oxygen exhaust port 422. The spacer 404 is nonporous and does not permit any molecules or ions to pass through. The cathode secondary layer 408 and the cathode 410 each consume input gas 114 that includes oxygen along with other contaminants such as nitrogen, argon, and other particles. The nonporous spacer 404 prevents the other contaminants from exiting the cathode secondary layer 408 and / or the cathode 410 and then ultimately entering the oxygen exhaust port 422. The oxygen exhaust port 422 only includes purified oxygen gas 108.

[0067] The anode cap 420 is nonporous and provides a barrier similar to that provided by the spacer 404. The anode cap 420 prevents contaminants, such as nitrogen, argon, or other particles, from entering the oxygen exhaust port 422. Further, the anode cap 420 prevents the purified oxygen gas 108 that is located within the anode 420 and / or the anode secondary layer 416 from exiting the system and reentering the atmosphere. The purified oxygen gas 108 is located within the anode 420 and the anode secondary layer 416. The interior edges (i.e., the edge along the oxygen exhaust port 422) of the anode 420 and / or the anode secondary layer 416 are open such that the purified oxygen gas 108 may exit and enter the oxygen exhaust port 422. The purified oxygen gas 108 exits the system by way of the oxygen exhaust port 422 where it may eventually be used on-site or harvested in a tank or other vessel.

[0068] Each of the anode 420 and the anode secondary layer 416 includes a nonporous edge 418. The nonporous edge 418 surrounds the perimeter of the anode 420 and the anode secondary layer 416. The nonporous edge 418 prevents the purified oxygen gas 108 from exiting either of the anode 420 and / or the anode secondary layer 416 and reentering the atmosphere. The nonporous edge 418, along with the electrolyte 412 and the anode cap 420, forces the purified oxygen gas 108 to exit the system by way of the oxygen exhaust port 422.

[0069] FIG. 5 is a schematic diagram of a cross-sectional view of the oxygen concentrator cell 402 further depicting the pathways of the input gas 114, oxygen-diminished output gas 115, oxygen gas, oxygen ions, and oxygen molecules. The oxygen concentrator cell 402 includes a leading edge 502 and a trailing edge 504. The input gas 114 passes over the oxygen concentrator cell 402 starting with the leading edge 502 and ending with the trailing edge 504. The input gas 114 may pass over the oxygen concentrator cell 402 beginning with the leading edge 502. Input gas 114 enters the oxygen concentrator cell 402 at the cathode secondary layer 408. Molecular diffusion causes the input gas 114 to pass into the porous cathode secondary layer 408 at 506 until it reaches electrolyte 412. Molecular diffusion causes the molecules of the input gas 114 to travel through the cathode secondary layer 408 and the cathode 410. The spacer 404 prevents the molecules of the input gas 114 from entering the oxygen exhaust port 422.

[0070] The oxygen molecules are reduced (see Equation 1) near the surface and at the surface of the electrolyte 412 where the oxygen molecular bond is broken at 508. The crystal structure of the electrolyte 412 has oxygen deficiencies and causes the oxygen ions to travel through the electrolyte 412. The electrolyte 412 exclusively accepts oxygen ions at 510. At the opposite end of the electrolyte 412 at the surface of the anode 420, the oxygen ions are oxidized (see Equation 2), and the oxygen molecular bond is reformed at 512. A voltage or EMF is applied to the electrochemical stack 202 and this EMF causes the oxygen molecules to form near the surface of the anode 420 as shown at 512, even if there exists a high concentration of oxygen molecules in the anode 420 and the anode secondary layer 416. The anode 420 and the anode secondary layer 416 include only purified oxygen gas 108. The nonporous anode cap 420 prevents the purified oxygen gas 108 from exiting the system and reentering the atmosphere at 518. Molecular diffusion causes the purified oxygen gas 108 to leave the anode 420 and / or the anode secondary layer 416 to enter the oxygen exhaust port 422 at 516. The nonporous edge 418 prevents the purified oxygen gas 108 from exiting the anode 420 and / or the anode secondary layer 416 and reentering the environment. The purified oxygen gas 108 may travel the length of the electrochemical stack 202 up the oxygen exhaust port 422 where it may eventually be used on-site or harvested in a tank or other vessel.

[0071] As the system is operating, the purified oxygen gas 108 within the anode 420 and / or the anode secondary layer 416 builds pressure. Further, the input gas 114 within the cathode 404 and / or the cathode secondary layer 406 exists at one atmosphere of pressure when operating at sea level at ambient conditions. In an instance where the input gas 114 is air, the input gas 114 includes approximately 21% oxygen. In this instance, where purified oxygen gas 108 exists at some pressure within the anode and gas comprising 21% oxygen exists within the cathode at one atmosphere of pressure, the concentration gradient would push oxygen gas to the cathode where there is less concentration of oxygen. However, the voltage applied to the system causes the oxygen to move opposite the concentration gradient to exit the electrolyte 460 and enter the anode at 514.

[0072] The electrochemical stacks described herein are designed such that oxygen is electrochemically pumped from outside the oxygen concentrator cell into the porous region inside the oxygen concentrator cell (i.e., to the anode). The porous anode region is sealed along the outside edges of the oxygen concentrator cell, but there is an open path to the oxygen port located in the center of the oxygen concentrator cell. As oxygen migrates into the porous anode region, internal pressure rises. This pressure drives the flow of oxygen to the oxygen port. A ring-shaped washer is attached to the top of the oxygen concentrator cell, surrounding the oxygen port. This washer creates a “chimney” for oxygen transport. A set of ribs is attached to the top of each oxygen concentrator cell, providing structural support for the stacked assembly of oxygen concentrator cells. These ribs carry current from one oxygen concentrator cell to the next.

[0073] The electrochemical stack described herein does not require air filtration or dehumidification because particulates and humidity do not diffuse across the membrane. However, system filtration may be determined by the tolerance of balance of the environmental conditions of the inlet process air. Gross contamination of the inlet air may cause secondary system problems that will not manifest in the electrochemical stack.

[0074] The ceramic oxygen concentration systems described herein comprise systems for thermal management that are driven by a preheat initiation time, total power use, fault tolerance, and service life. In some cases, the preheat initiation time may include about six hours of preheating when beginning with a system at about room temperature. This preheat time may minimize thermal stresses on the oxygen concentrator cells. Preheat time and total system power-use limitations may be referenced to set the maximum power levels applied to process air heaters. During steady-state operations, system heat is largely supplied by heat generated by the electrochemical stack. During startup, electrochemical stacks do not operate; system heating is provided by the process air heaters. The ceramic oxygen concentrator systems described herein may multiple heater elements to ensure system performance when one heater element fails. Some systems described herein may comprise one, two, three, four, or more heaters. Because of system startup heating requirements and fault tolerance requirements, nominal heating power during steady-state operations is less than 10% of the maximum power rating for the cases evaluated for this assessment.

[0075] The ceramic oxygen concentrator systems described herein may be operated at an elevated temperature from about 500° C. to about 950° C., and may specifically be operated at an elevated temperature from about 650° C. to about 800° C. The operating temperature may be actively controlled and maintained through the use of heaters, heat exchangers, and insulation. Total energy consumption will be lower when operating in hot environments and higher when operating in cold environments, given the respective reduced or increased heater power required to maintain temperature. Because the ceramic oxygen concentrator systems described herein may be insulated, and the process air heat exchanger may be equipped with a high effectivity, the projected differences in energy use may be assumed to be small. The heat energy needed to heat the process air from ambient to operating temperature is a function of the mass flow of the process air, the ΔT between ambient and operating temperature, and the specific heat of air (Q=m c ΔT). The specific heat of air is unchanged, and the mass flow of process air is unchanged. The ΔT between 20° C. and 700° C. is 680° C., while the ΔT between 45° C. and 700° C. is 655° C. The projected energy savings of operating at 45° C. rather than 20° C. is 3.7%.

[0076] Power supply, power distribution, and system control electronics may use commercially available components. Automotive-grade electronics are commonly rated for-40° C. to 105° C. The ceramic oxygen concentrator systems described herein may operate in any environment within the rated temperature range of the power and control electronics, which are the limiting factors.

[0077] The ceramic oxygen concentrator systems described herein may be operated with varying atmospheric pressures and may specifically be operated at various elevations relative to sea level without impacting the oxygen separation process, the overall purity of the oxygen produced, or the delivery pressure. The edges of the ion transport membrane in the oxygen concentrator cells described herein are hermetically sealed, and oxygen collected inside the oxygen concentrator cell is isolated from the outside environment. The oxygen concentrator cells described herein have been evaluated at a pressure differential of 1.38 MPa (200 psig). Terrestrial environmental pressures range from 0.1 MPa (14.7 psia) at sea level to 0.05 MPa (8.1 psia) at 5400 m of elevation. Stresses caused by environmental pressure changes are minor compared with stress conditions applied during

[0078] In some cases, operating the ceramic oxygen concentrator systems described herein at high elevation / reduced pressure reduces the peak oxygen production rate for an individual device. Process air is used to regulate internal temperatures, and air at high elevations has less thermal mass and a reduced capacity to regulate internal temperatures. The systems described herein are designed to operate nominally at any altitude between sea level and 3000 m.

[0079] The systems, methods, and devices described herein output oxygen comprising a purity that is equal to or in excess of 99.9%. The main constituent of trace material is water vapor. The water vapor is believed to enter the oxygen by permeating across the ceramic washer seals from the process air into the oxygen. Water vapor contamination observed in testing is limited to <50 ppmv but was limited in the range of air stream inlet water vapor. The ion transport membranes described herein are capable of transporting oxygen ions that are sealed off from the outside environment. The two ways for chemical constituents to get from process air to the oxygen generation region are via water vapor permeation through the washer seal and oxygen ion transport.

[0080] A chemical analysis of the purified oxygen output by the systems, methods, and devices described herein was conducted. Reported oxygen purity was >99.9%, which is the highest purity possible given the limitations of the chemical analysis. Combined nitrogen and argon was determined to be less than 100 ppmv (the limits of the chemical analysis), carbon dioxide was less than 1 ppmv, methane was less than 1 ppmv, and all other hydrocarbons were less than 1 ppmv. Water vapor was not evaluated due to limitations in the method of chemical analysis.

[0081] FIG. 6 is a schematic block diagram of a system 600 for thermal heat capture and further for concentration of high purity oxygen. The system 600 includes a ceramic oxygen concentrator 402 that includes at least an electrochemical stack 104 and a heat exchanger 110. The heat exchanger 110 receives an input gas 114 that comprises oxygen and may be disposed at ambient temperature. The heat exchanger 110 heats the input gas 114 and outputs heated input output gas 116, which is fed to the electrochemical stack 104. In some cases, the heated input output gas 116 may be further heated by a heater (see heater 112).

[0082] The electrochemical stack 104 outputs purified oxygen gas 108 that may be stored in a storage vessel 614 and / or provided for immediate use 616. The electrochemical stack 104 additionally outputs high temperature oxygen-diminished output gas 116 that may be fed through the heat exchanger 110. The heat exchanger 110 captures heat from the high temperature oxygen-diminished output gas 116. The heat exchanger 110 outputs moderate heat oxygen-diminished gas 618 which may be provided to a secondary unit 120 and / or released into the atmosphere 622.

[0083] As shown in FIG. 6, the heat exchanger 110 receives the input gas 114, which may be disposed at ambient temperature or may be heated above ambient temperature. The input gas 114 is passively heated by the high temperature oxygen-diminished output gas 116 that has exited the electrochemical stack 104 and entered the heat exchanger 110. This passive heating causes the input gas 114 to be heated into heated input gas 602. Additionally, the heat exchanger 110 receives the high temperature oxygen-diminished output gas 116, and passively cools this gas with the presence of the cooler input gas 114. The heat exchanger 110 thus cools the high temperature oxygen-diminished output gas 116 to the moderate temperature oxygen diminished output gas 618.

[0084] The high temperature oxygen-diminished gas 116 may comprise a temperature from about 650° C. to about 850° C., and may specifically comprise a temperature from about 700° C. to about 775° C. The moderate temperature oxygen-diminished gas 618 may comprise a temperature from about 50° C. to about 250° C., and may specifically comprise a temperature from about 90° C. to about 140° C.

[0085] The secondary unit 120 may include one or more secondary units 120 performing the same function or performing different functions. The secondary unit 120 may include, for example, a dry air sterilizer, dry air fabric heater, steam generator, water heater, room heater, building heater, film shrinker, dryer, process preheater, water purifier, water desalination device, agricultural processor, food processor, snow melter, de-icing device, and so forth.

[0086] FIG. 7 is a schematic flow chart diagram of a method 700 for capturing waste heat output by an electrochemical stack of a ceramic oxygen concentrator. The method 700 includes heating at 702 an electrochemical stack of a ceramic oxygen concentrator. The method 700 includes providing at 704 an input gas to the ceramic oxygen concentrator, wherein the input gas comprises oxygen. The method 700 includes receiving at 706 an oxygen-diminished output gas output by the ceramic oxygen concentrator, wherein the oxygen-diminished output gas comprises an elevated temperature, and wherein the elevated temperature may comprise from about 650° C. to about 850° C. The method 700 includes processing at 708 the oxygen-diminished output gas with a heat exchanger to remove heat from the oxygen-diminished output gas and output the oxygen-diminished output gas at a moderately elevated temperature, wherein the moderately elevated temperature may comprise from about 50° C. to about 250° C. The method 700 includes providing at 710 the oxygen-diminished output gas at the moderately elevated temperature to a secondary system. The secondary system may include one or more of a dry air sterilizer, dry air fabric heater, steam generator, water heater, room heater, building heater, film shrinker, dryer, process preheater, water purifier, water desalination device, agricultural processor, food processor, snow melter, de-icing device, and so forth.EXAMPLES

[0087] The following examples pertain to further embodiments.

[0088] Example 1 is a system for concentrating oxygen gas. The system includes a plurality of oxygen concentrator cells. Each oxygen concentrator cell of the plurality of oxygen concentrator cells comprises a spacer, a cathode, an electrolyte, an anode, and an anode cap, wherein the spacer is in contact with the electrolyte. Each oxygen concentrator cell further comprises a hole disposed therethrough configured for providing an oxygen exhaust port. The electrolyte comprises a ceramic having oxygen ion deficiencies such that the electrolyte is configured for exclusively accepting oxygen ions.

[0089] Example 2 is a system as in Example 1, wherein the cathode and the anode comprise a porous material.

[0090] Example 3 is a system as in any of Examples 1-2, wherein the spacer, the electrolyte and the anode cap comprise a nonporous material.

[0091] Example 4 is a system as in any of Examples 1-3, wherein the oxygen concentrator cell further comprises a cathode secondary layer, and wherein the cathode secondary layer and the cathode comprise a porous material configured for accepting an input gas comprising oxygen.

[0092] Example 5 is a system as in any of Examples 1-4, further comprising an electricity source in electrical communication with each oxygen concentrator cell 204 of the plurality of oxygen concentrator cells such that an electric potential is applied to the electrochemical stack, wherein a surplus of electrons exists at the cathode.

[0093] Example 6 is a system as in any of Examples 1-5, wherein the surplus of electrons at the cathode causes oxygen molecules in the input gas to undergo a reduction reaction such that one oxygen molecule generates two oxygen ions.

[0094] Example 7 is a system as in any of Examples 1-6, wherein a deficiency of electrons exists at the anode, wherein the deficiency of electrons at the anode causes oxygen ions to undergo an oxidation reaction such that two oxygen ions generate one oxygen molecule, wherein the oxygen exhaust port is configured for receiving the one oxygen molecule.

[0095] Example 8 is a system as in any of Examples 1-7, wherein the oxygen concentrator cell 204 comprises a rectangular shape comprising a width and a height, wherein the width is longer than the height.

[0096] Example 9 is a system as in any of Examples 1-8, wherein the oxygen concentrator cell 204 comprises one or more curved edges.

[0097] Example 10 is a system as in any of Examples 1-9, wherein the oxygen concentrator cell 204 comprises one or more curved sides.

[0098] Example 11 is a system as in any of Examples 1-10, wherein the spacer is co-sintered with one or more other layers of the oxygen concentrator cell 204 such that the spacer is secured to the anode cap, or alternatively secured to the electrolyte.

[0099] Example 12 is a system as in any of Examples 1-11, wherein the oxygen concentrator cell 204 further comprises ribbing.

[0100] Example 13 is a system as in any of Examples 1-12, wherein the ribbing is co-sintered with one or more other layers of the oxygen concentrator cell 204 such that the ribbing is secured to the anode cap.

[0101] Example 14 is a system. The system includes a first stage oxygen concentrator and purifier. The system includes a second stage oxygen concentrator and purifier. The first stage oxygen concentrator and purifier outputs a first oxygen output gas. The second stage oxygen concentrator and purifier receive the first oxygen output gas as a second input gas.

[0102] Example 15 is a system as in Example 14, wherein the first stage oxygen concentrator and purifier comprise one or more of a first electrochemical stack.

[0103] Example 16 is a system as in any of Examples 14-15, wherein the second stage oxygen concentrator and purifier comprise one or more of a second electrochemical stack.

[0104] Example 17 is a system as in any of Examples 14-16, wherein each of the first electrochemical stack and the second electrochemical stack comprises an anode, a cathode, and an electrolyte.

[0105] Example 18 is a system as in any of Examples 14-17, wherein each of the first electrochemical stack and the second electrochemical stack further comprises an anode secondary layer and a cathode secondary layer.

[0106] Example 19 is a system as in any of Examples 14-18, wherein one of the first electrochemical stack or the second electrochemical stack comprises an anode cap.

[0107] Example 20 is a system as in any of Examples 14-19, wherein one of the first electrochemical stack or the second electrochemical stack comprises a cathode cap.

[0108] Example 21 is a system as in any of Examples 14-20, wherein the first electrochemical stack receives a first input gas comprising oxygen.

[0109] Example 22 is a system as in any of Examples 14-21, wherein the first input gas is air.

[0110] Example 23 is a system as in any of Examples 14-22, wherein the first electrochemical stack outputs a first oxygen-diminished gas and further outputs the first oxygen output gas.

[0111] Example 24 is a system as in any of Examples 14-23, wherein the second electrochemical stack receives the first oxygen output gas, and wherein the second electrochemical stack outputs a second oxygen-diminished gas and further outputs a second oxygen output gas.

[0112] Example 25 is a system as in any of Examples 14-24, wherein the second oxygen output gas is pressurized at a higher pressure than the first oxygen output gas.

[0113] Example 26 is a system as in any of Examples 14-25, wherein the second oxygen output gas comprises a higher oxygen purity concentration than the first oxygen output gas.

[0114] Example 27 is a system as in any of Examples 14-26, wherein the first oxygen output gas is stored in a low-pressure storage vessel, wherein the low-pressure storage vessel has a maximum pressure 1000 psig or less.

[0115] Example 28 is a system as in any of Examples 14-27, wherein the second oxygen output gas is stored in a high-pressure storage vessel, and wherein the high-pressure storage vessel has a maximum pressure of about 3300 psig or less.

[0116] Example 29 is a system as in any of Examples 14-28, wherein the high-pressure storage vessel has a maximum pressure of about 10,000 psig or less.

[0117] Example 30 is a system as in any of Examples 14-29, further comprising a first heater configured to heat the first electrochemical stack.

[0118] Example 31 is a system as in any of Examples 14-30, further comprising a second heater configured to heat the second electrochemical stack.

[0119] Example 32 is a system as in any of Examples 14-31, further comprising a direct current (DC) power source configured to supply a voltage to one or more of the first electrochemical stack or the second electrochemical stack.

[0120] Example 33 is a system as in any of Examples 14-32, further comprising non-flammable and porous insulation disposed around one or more of the first electrochemical stack or the second electrochemical stack.

[0121] Example 34 is a system as in any of Examples 14-33, wherein each of the first electrochemical stack and the second electrochemical stack is constructed of a ceramic material.

[0122] Example 35 is a system as in any of Examples 14-34, wherein each of the first electrochemical stack and the second electrochemical stack comprises a plurality of oxygen concentrator cells.

[0123] Example 36 is a system as in any of Examples 14-35, wherein the first electrochemical stack comprises an anode layer disposed within an interior region of each of the plurality of oxygen concentrator cells.

[0124] Example 37 is a system as in any of Examples 14-36, wherein the first electrochemical stack comprises a cathode layer disposed within an exterior region of each of the plurality of oxygen concentrator cells.

[0125] Example 38 is a system as in any of Examples 14-37, wherein the second electrochemical stack comprises a cathode layer disposed within an interior region of each of the plurality of oxygen concentrator cells.

[0126] Example 39 is a system as in any of Examples 14-38, wherein the second electrochemical stack comprises an anode layer disposed within an exterior region of each of the plurality of oxygen concentrator cells.

[0127] Example 40 is a system. The system includes a first stage oxygen concentrator that receives an input gas and outputs a first oxygen output gas; a second stage oxygen concentrator comprising a second electrochemical stack, wherein the second stage oxygen concentrator receives the first oxygen output gas and outputs a second oxygen output gas; wherein the first oxygen output gas is stored at a first storage pressure up to a first maximum pressure; wherein the second oxygen output gas is stored at a second storage pressure up to a second maximum pressure; and wherein the second maximum pressure is greater than the first maximum pressure.

[0128] Example 41 is a system as in Example 40, wherein the first stage oxygen concentrator comprises a first electrochemical stack.

[0129] Example 42 is a system as in Example 40-41, wherein the first stage oxygen concentrator outputs the first oxygen output gas and further outputs a first oxygen-reduced gas; wherein the second stage oxygen concentrator outputs the second oxygen output gas and further outputs a second oxygen-reduced gas; and wherein the second oxygen output gas comprises a higher oxygen purity concentration than the first oxygen output gas.

[0130] Example 43 is a system as in Example 40-42, further comprising: a first stage inlet port configured to receive the input gas; a first gaseous conduit in gaseous communication with the first stage inlet port; an insulation disposed around the first gaseous conduit; and a heater configured to heat the input gas as it passes through the first gaseous conduit to generate heated input gas.

[0131] Example 44 is a system as in Example 40-43, wherein the first stage oxygen concentrator comprises a first electrochemical stack that comprises a first plurality of electrochemical cells arranged in series, and wherein the system further comprises: a first stage oxygen outlet pipeline attached to each of the first plurality of electrochemical cells and configured to receive the first oxygen output gas; and a first gas storage vessel in gaseous communication with the first stage oxygen outlet pipeline; wherein the first gas storage vessel is configured to store the first oxygen output gas at the first storage pressure up to the first maximum pressure.

[0132] Example 45 is a system as in Example 40-44, wherein the second electrochemical stack comprises a second plurality of electrochemical cells arranged in series, and wherein the system further comprises: a second stage inlet pipeline in gaseous communication with the first gas storage vessel, wherein the first oxygen output gas is fed to the second plurality of electrochemical cells by way of the second stage inlet pipeline; and a heating element disposed around the second electrochemical stack.

[0133] Example 46 is a system as in Example 40-45, further comprising: a second stage outlet pipeline configured to receive the second oxygen output gas that is concentrated by the second plurality of electrochemical cells; and a second storage vessel in gaseous communication with the second stage outlet pipeline, wherein the second storage vessel is configured to store the second oxygen output gas at the second storage pressure up to the second maximum pressure.

[0134] Example 47 is a system as in Example 40-46, wherein the first oxygen output gas is fed to the second electrochemical stack at the first storage pressure up to the first maximum pressure; and wherein the second oxygen output gas is output by the second electrochemical stack and pressurized in a chamber surrounding the second electrochemical stack prior to being stored in a storage vessel at the second storage pressure up to the second maximum pressure.

[0135] Example 48 is a system as in Example 40-47, wherein each of the first electrochemical stack and the second electrochemical stack comprises: an anode comprising a porous material that accepts oxygen molecules; a cathode comprising a porous material configured to receive a gas comprising oxygen, wherein the gas comprising oxygen is one of the input gas or the first oxygen output gas; and an electrolyte comprising a nonporous material configured to receive oxygen ions.

[0136] Example 49 is a system as in Example 40-48, wherein each of the first electrochemical stack and the second electrochemical stack further comprises: an anode secondary layer comprising a porous material that accepts oxygen molecules; and a cathode secondary layer comprising a porous material configured to receive a gas comprising oxygen, wherein the gas comprising oxygen is one of the input gas or the first oxygen output gas.

[0137] Example 50 is a system as in Example 40-49, wherein one of the first electrochemical stack or the second electrochemical stack comprises an anode cap; and wherein one of the first electrochemical stack or the second electrochemical stack comprises a cathode cap.

[0138] Example 51 is a system as in Example 40-50, wherein the input gas is ambient air.

[0139] Example 52 is a system as in Example 40-51, further comprising a low-pressure storage vessel comprising a maximum pressure from about 5 psig to about 200 psig, and wherein the first oxygen output gas is stored in the low-pressure storage vessel.

[0140] Example 53 is a system as in Example 40-52, further comprising a high-pressure storage vessel comprising a maximum pressure from about 200 psig to about 3,500 psig, and wherein the second oxygen output gas is stored in the high-pressure storage vessel.

[0141] Example 54 is a system as in Example 40-53, further comprising a high-pressure storage vessel comprising a maximum pressure from about 3,000 psig to about 10,000 psig, and wherein the second oxygen output gas is stored in the high-pressure storage vessel.

[0142] Example 55 is a system as in Example 40-54, further comprising non-flammable and porous insulation disposed around one or more of the first electrochemical stack or the second electrochemical stack.

[0143] Example 56 is a system as in Example 40-55, wherein the first electrochemical stack comprises a first plurality of oxygen concentrator cells; wherein the second electrochemical stack comprises a second plurality of oxygen concentrator cells; and wherein each of the first plurality of oxygen concentrator cells and the second plurality of oxygen concentrator cells comprises a ceramic material.

[0144] Example 57 is a system as in Example 40-56, wherein at least a portion of the first plurality of oxygen concentrator cells comprises an anode layer disposed within a first interior region of each of the first plurality of oxygen concentrator cells; wherein at least a portion of the first plurality of oxygen concentrator cells comprises a cathode layer located at a first edge region of each of the first plurality of oxygen concentrator cells; wherein at least a portion of the second plurality of oxygen concentrator cells comprises a cathode layer disposed within a second interior region of each of the second plurality of oxygen concentrator cells; and wherein at least a portion of the second plurality of oxygen concentrator cells comprises an anode layer disposed within a second edge region of each of the second plurality of oxygen concentrator cells.

[0145] Example 58 is a system as in Example 40-57, wherein at least a portion of the first plurality of oxygen concentrator cells comprises a cathode layer disposed within a first interior region of each of the first plurality of oxygen concentrator cells; wherein at least a portion of the first plurality of oxygen concentrator cells comprises an anode layer located at a first edge region of each of the first plurality of oxygen concentrator cells; wherein at least a portion of the second plurality of oxygen concentrator cells comprises an anode layer disposed within a second interior region of each of the second plurality of oxygen concentrator cells; and wherein at least a portion of the second plurality of oxygen concentrator cells comprises a cathode layer disposed within a second edge region of each of the second plurality of oxygen concentrator cells.

[0146] Example 59 is a system as in Example 40-58, receiving an input gas comprising oxygen; providing the input gas to a first stage oxygen concentrator; receiving from the first stage oxygen concentrator a first oxygen output gas and a first oxygen-reduced gas; storing the first oxygen output gas in a first storage vessel at a first storage pressure up to a first maximum pressure; providing the first oxygen output gas to a second stage oxygen concentrator comprising a second stage electrochemical stack; receiving from the second stage electrochemical stack a second oxygen output gas and a second oxygen-reduced gas; and storing the second oxygen output gas in a second storage vessel at a second storage pressure up to a second maximum pressure; wherein the second maximum pressure is greater than the first maximum pressure; and wherein the second oxygen output gas comprises a higher oxygen purity concentration than the first oxygen output gas.

[0147] Example 60 is a system. The system includes an electrochemical stack comprising a plurality of oxygen concentrator cells, wherein each of the plurality of oxygen concentrator cells comprises: a ceramic electrolyte membrane comprising an oxygen ion conducting material; a cathode layer; and an anode layer. The system includes a heat exchanger that receives an input gas and an oxygen-diminished output gas, wherein the oxygen-diminished output gas is output by the electrochemical stack. The system includes a secondary unit in fluid communication with the heat exchanger. The heat exchanger heats the input gas prior to the input gas being provided to the electrochemical stack. The heat exchanger cools the oxygen-diminished output gas prior to the oxygen-diminished output gas being provided to the secondary unit. The secondary unit is heated with the oxygen-diminished output gas.

[0148] Example 61 is a system as in Example 60, wherein the secondary unit comprises one or more of an air sterilizer, fabric heater, steam generator, water heater, air heater, film shrinker, dryer, process preheater, water purifier, water desalination assembly, snow melter, or de-icing assembly.

[0149] Example 62 is a system as in any of Examples 60-61, wherein the secondary unit comprises a sterilizer.

[0150] Example 63 is a system as in any of Examples 60-62, wherein the secondary unit comprises a purifier.

[0151] Example 64 is a system as in any of Examples 60-63, wherein the secondary unit comprises one or more of an agricultural processor or food processor.

[0152] Example 65 is a system as in any of Examples 60-64, wherein the oxygen-diminished output gas comprises a temperature from about 500 degrees Celsius to about 900 degrees Celsius prior to entering the heat exchanger; and wherein the oxygen-diminished output gas comprises a temperature from about 150 degrees Celsius to about 500 degrees Celsius when exiting the heat exchanger.

[0153] Example 66 is a system as in any of Examples 60-65, wherein the oxygen-diminished output gas comprises a temperature from about 150 degrees Celsius to about 500 degrees Celsius when provided to the secondary unit.

[0154] Example 67 is a system as in any of Examples 60-66, further comprising a boost heater, wherein the boost heater heats the oxygen-diminished output gas after the oxygen-diminished output gas has been cooled by the heat exchanger, and before the oxygen-diminished output gas is provided to the secondary unit.

[0155] Example 68 is a system as in any of Examples 60-67, further comprising a heater, wherein the heater heats the input gas before the input gas is provided to the heat exchanger.

[0156] Example 69 is a system as in any of Examples 60-68, wherein the electrochemical stack receives the input gas, wherein the input gas comprises oxygen; and wherein the electrochemical stack outputs: the oxygen-diminished output gas; and high-purity oxygen gas, wherein the high-purity oxygen gas comprises a purity in excess of 95 percent.

[0157] Example 70 is a system as in any of Examples 60-69, wherein the oxygen-diminished output gas is provided to the secondary unit and further released into the atmosphere after being cooled by the heat exchanger.

[0158] Example 71 is a system as in any of Examples 60-70, further comprising a blower, wherein the blower feeds the input gas into the heat exchanger.

[0159] Example 72 is a system as in any of Examples 60-71, further comprising a thermal enclosure, wherein each of the electrochemical stack, the heat exchanger, and the secondary unit is disposed within an interior space defined by the thermal enclosure.

[0160] Example 73 is a system as in any of Examples 60-72, further comprising: a second electrochemical stack; a first storage vessel; and a second storage vessel; wherein first purified oxygen gas output by the electrochemical stack is fed to the first storage vessel; wherein the first purified oxygen gas is input to the second electrochemical stack; and wherein second purified oxygen gas is output by the second electrochemical stack and fed to the second storage vessel.

[0161] Example 74 is a system as in any of Examples 60-73, wherein the first storage vessel stores the first purified oxygen gas at a first pressure, wherein the second storage vessel stores the second purified oxygen gas at a second pressure, and wherein the second pressure is greater than the first pressure.

[0162] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the described features or acts described above. Rather, the described features and acts are disclosed as example forms of implementing the claims.

[0163] While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents. The foregoing description has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. Further, it should be noted that any or all of the aforementioned alternate implementations may be used in any combination desired to form additional hybrid implementations of the disclosure.

[0164] Further, although specific implementations of the disclosure have been described and illustrated, the disclosure is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the disclosure is to be defined by the claims appended hereto, any future claims submitted here and in different applications, and their equivalents.

Claims

1. A system comprising:an electrochemical stack comprising a plurality of oxygen concentrator cells, wherein each of the plurality of oxygen concentrator cells comprises:a ceramic electrolyte membrane comprising an oxygen ion conducting material;a cathode layer; andan anode layer;a heat exchanger that receives an input gas and an oxygen-diminished output gas, wherein the oxygen-diminished output gas is output by the electrochemical stack; anda secondary unit in fluid communication with the heat exchanger;wherein the heat exchanger heats the input gas prior to the input gas being provided to the electrochemical stack;wherein the heat exchanger cools the oxygen-diminished output gas prior to the oxygen-diminished output gas being provided to the secondary unit; andwherein the secondary unit is heated with the oxygen-diminished output gas.

2. The system of claim 1, wherein the secondary unit comprises one or more of an air sterilizer, fabric heater, steam generator, water heater, air heater, film shrinker, dryer, process preheater, water purifier, water desalination assembly, snow melter, or de-icing assembly.

3. The system of claim 1, wherein the secondary unit comprises a sterilizer.

4. The system of claim 1, wherein the secondary unit comprises a purifier.

5. The system of claim 1, wherein the secondary unit comprises one or more of an agricultural processor or food processor.

6. The system of claim 1, wherein the oxygen-diminished output gas comprises a temperature from about 500 degrees Celsius to about 900 degrees Celsius prior to entering the heat exchanger; andwherein the oxygen-diminished output gas comprises a temperature from about 100 degrees Celsius to about 500 degrees Celsius when exiting the heat exchanger.

7. The system of claim 1, wherein the oxygen-diminished output gas comprises a temperature from about 100 degrees Celsius to about 500 degrees Celsius when provided to the secondary unit.

8. The system of claim 1, further comprising a boost heater, wherein the boost heater heats the oxygen-diminished output gas after the oxygen-diminished output gas has been cooled by the heat exchanger, and before the oxygen-diminished output gas is provided to the secondary unit.

9. The system of claim 1, further comprising a heater, wherein the heater heats the input gas before the input gas is provided to the heat exchanger.

10. The system of claim 1, wherein the electrochemical stack receives the input gas, wherein the input gas comprises oxygen; andwherein the electrochemical stack outputs:the oxygen-diminished output gas; andhigh-purity oxygen gas, wherein the high-purity oxygen gas comprises a purity in excess of 95 percent.

11. The system of claim 1, wherein the oxygen-diminished output gas is provided to the secondary unit and further released into the atmosphere after being cooled by the heat exchanger.

12. The system of claim 1, further comprising a blower, wherein the blower feeds the input gas into the heat exchanger.

13. The system of claim 1, further comprising a thermal enclosure, wherein each of the electrochemical stack, the heat exchanger, and the secondary unit is disposed within an interior space defined by the thermal enclosure.

14. The system of claim 1, further comprising:a second electrochemical stack;a first storage vessel; anda second storage vessel;wherein first purified oxygen gas output by the electrochemical stack is fed to the first storage vessel;wherein the first purified oxygen gas is input to the second electrochemical stack; andwherein second purified oxygen gas is output by the second electrochemical stack and fed to the second storage vessel.

15. The system of claim 14, wherein the first storage vessel stores the first purified oxygen gas at a first pressure, wherein the second storage vessel stores the second purified oxygen gas at a second pressure, and wherein the second pressure is greater than the first pressure.

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