Regenerable fuel, and systems and methods for releasing energy using the regenerable fuel

Abstract

A regenerable fuel comprising: a first component oxidizable by an oxidizing fluid to release energy; and a second component configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component. The energy released is thermal energy. A system and a method using the fuel to release the energy.

Description

REGENERABLE FUEL, AND SYSTEMS AND METHODS FOR RELEASING ENERGY USING THE REGENERABLE FUELTECHNICAL FIELD

[0001] The present disclosure relates to the field of energy release. More specifically, but not exclusively, the present disclosure relates to energy release systems and methods using regenerable fuel, as well as the regenerable fuel itself.BACKGROUND

[0002] Regenerable fuels are being explored as a promising alternative to fossil fuels for energy release . However, proposed systems have not enjoyed widespread use because of their complex and costly designs.

[0003] There is therefore a need for regenerable fuel and systems using the same for energy release which overcome at least some of the disadvantages of the prior art.SUMMARY

[0004] According to the present disclosure, there is provided a regenerable fuel, and systems and methods that use the regenerable fuel for energy release, that overcome at least some of the disadvantages of the prior art.

[0005] Developers have identified that regenerable fuel of the type that exploits oxidation / reduction processes may be improved by ensuring that the fuel remains able to combust whilst avoiding melting. Broadly, Developers have discovered that combining a first component which can be oxidized and reduced with a second component that can modulate the properties of the first component to avoid melting whilst permitting combustion provide an effective regenerable fuel that can overcome shortcomings of the prior art. Broadly, there is provided a system for releasing energy, the system comprising: at least one reactor module having an inlet connectable to an oxidizing fluid source; and a regenerable fuel disposed in the at least one reactor module, the regenerable fuel including a first component and a second component, the first component being oxidizable by the oxidizing fluid to release the energy, and the second component being configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component.

[0006] In certain embodiments, the first component comprises a metallic material.

[0007] In certain embodiments, the metallic material comprises iron and / or an iron-containing material.

[0008] In certain embodiments, the second component is made from a material which is chemically inert in the oxidizing fluid.

[0009] In certain embodiments, the second component comprises a ceramic.

[0010] In certain embodiments, one or both of the first component and the second component comprises at least one of: particles, powder, coatings, and a substrate.

[0011] In certain embodiments, the oxidizing fluid comprises oxygen and / or an oxygen containing fluid.

[0012] In certain embodiments, the system further comprises a fluid modulator for modulating a fluid flow through the inlet.

[0013] In certain embodiments, the at least one reactor module comprises at least one packed bed reactor.

[0014] In certain embodiments, the at least one packed bed reactor comprises a plurality of packed bed reactors which are fluidly connectable in series or in parallel.

[0015] In certain embodiments, the at least one reactor module has a cylindrical configuration, an annular configuration or a rectangular configuration.

[0016] In certain embodiments, the system further comprises the oxidizing fluid source.

[0017] In certain embodiments, the system further comprises a heater for providing energy to the regenerable fuel and / or the oxidizing fluid source.

[0018] In certain embodiments, the system further comprises a reducing fluid source fluidly connected to the at least one reactor module for providing reducing fluid to the regenerable fuel.

[0019] In certain embodiments, the reducing fluid comprises hydrogen, a hydrogen containing fluid, a hydrocarbon containing fluid or a carbon containing fluid.

[0020] In certain embodiments, the system further comprises a sensor at an outlet of the at least one reactor module for sensing a concentration of at least a component of the fluid at the outlet.

[0021] In certain embodiments, the system further comprises a generator operativelyconnected to an outlet of the at least one reactor module for converting the released energy to at least one of: electricity, steam, and light.

[0022] From another aspect, there is provided an electricity generator comprising: the system as described herein; and a heat engine drivingly connected to the system, the heat engine being operable to generate electricity from the released energy provided by the reactor.

[0023] From a yet further aspect, there is provided a method for releasing energy, the method comprising: providing a regenerable fuel in a reactor module, the regenerable fuel including a first component and a second component, the first component being oxidizable by an oxidizing fluid to generate the energy, and the second component being configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component; and causing oxidation of the first component by supplying input energy and the oxidizing fluid into the reactor module to releasing the energy through combustion.

[0024] In certain embodiments, the method further comprises modulating a rate of energy release by modulating at least one of: a flow rate of the oxidizing fluid at an inlet of the reactor module, a temperature of the oxidizing fluid, and a pressure in the reactor module.

[0025] In certain embodiments, increasing or reducing at least one of: the flow rate of the oxidizing fluid at the inlet of the reactor module and the pressure in the reactor module causes an increase or a reduction, respectively, in the rate of energy release.

[0026] In certain embodiments, the method further comprises stopping the flow of the oxidizing fluid into the reactor module to cause stoppage of energy release.

[0027] In certain embodiments, the method further comprises restarting the flow of the oxidizing fluid into the reactor module to restart the energy release.

[0028] In certain embodiments, the method further comprises supplying a reducing fluid into the reactor module to regenerate the regenerable fuel.

[0029] In certain embodiments, the method further comprises sensing a concentration of at least a component of the reducing fluid at an outlet of the reactor module; and in response to the concentration meeting or being greater than a predetermined threshold, stopping supply of the reducing fluid into the reactor module, or detecting a pressure difference across the reactor module and in response to the pressure difference being less than a predetermined threshold, stoppingsupply of the reducing fluid into the reactor module.

[0030] In certain embodiments, the supplying the energy comprises heating the regenerable fuel.

[0031] In certain embodiments, the supplying the energy comprises heating the oxidizing fluid.

[0032] In certain embodiments, the method further comprises harnessing the released energy to drive an engine.

[0033] In certain embodiments, the method further comprises converting the released energy to electricity.

[0034] In certain embodiments, the first component comprises a metallic material.

[0035] In certain embodiments, the metallic material comprises iron and / or iron containing material.

[0036] In certain embodiments, the second component is made from a material which is chemically inert in the oxidizing fluid.

[0037] In certain embodiments, the second component comprises a ceramic.

[0038] In certain embodiments, one or both of the first component and the second component comprises at least one of: particles, powder, coatings, and a substrate.

[0039] In certain embodiments, the oxidizing fluid comprises oxygen and / or an oxygen containing fluid.

[0040] In certain embodiments, the reducing fluid comprises hydrogen, a hydrogen containing fluid, a hydrocarbon including fluid or a carbon containing fluid.

[0041] From a further aspect, there is provided a regenerable fuel comprising: a first component oxidizable by an oxidizing fluid to release thermal energy; and a second component configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component.

[0042] In certain embodiments, the first component comprises a metallic material, and optionally the metallic material is in the form of a powder.

[0043] In certain embodiments, the metallic material comprises iron and / or iron containingmaterial.

[0044] In certain embodiments, the second component is made from a material which is chemically inert in the oxidizing fluid.

[0045] In certain embodiments, the second component comprises a ceramic.

[0046] In certain embodiments of the abovementioned system, generator, method and fuel, there is further provided a filler material between the regenerable fuel and the reactor module for minimizing or avoiding separation of the regenerable fuel and the housing. The filler material may comprise an adhesive inert material, such as an adhesive ceramic, to which the first material can adhere. In other embodiments, the adhesive material may comprise a mesh or a foam disposed between the regenerable fuel and the reactor module.

[0047] Certain embodiments of the present technology have associated advantages such as one or more of: zero pollutant emissions during combustion of the regenerable fuel; systems using the regenerable fuel for energy generation do not require cyclone or permeable conduits which reduces the cost and complexity of production compared to prior art systems; energy generation using the regenerable fuel of the present technology has high efficiency (for example, when iron is used as the first component, above 80% of iron converts to iron oxide (Fe3O4));the regenerable fuel has a high energy density, is safe for storing, has a long storage duration, has multiple life cycles, and is scalable (e.g. from kW to GW).

[0048] As used herein, unless expressly provided otherwise, “inert” means not reactive or minimally reactive.

[0049] As used herein, unless expressly provided otherwise, “first”, “second”, “third”, etc. are used as adjectives only for the purpose of allowing for distinction between the nouns that they modify from one another, and not for the purpose of describing any particular relationship between those nouns.

[0050] As used herein, unless expressly provided otherwise, the singular form “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0051] As used herein, unless expressly provided otherwise, the term “about” in the context of a given value or range refers to a value or range that is within 20%, preferably within 10%, and more preferably within 5% of the given value or range.

[0052] As used herein, the term “and / or” is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, “A and / or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

[0053] Implementations of the present technology each have at least one of the above- mentioned objects and / or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above- mentioned object may not satisfy this object and / or may satisfy other objects not specifically recited herein.

[0054] The foregoing and other features will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Embodiments of the disclosure will be described by way of example only with reference to the accompanying drawings, in which:FIGs. 1 A and IB are schematic illustrations of a regenerable fuel which comprises first and second components, according to embodiments of the present technology.FIG. 2 is a schematic illustration of a system for energy release in which the regenerable fuel of FIG. 1 can be used, according to embodiments of the present technology.FIGs. 3A-C are schematic illustrations of the reactor module of the system of FIG. 2 in different use scenarios, according to embodiments of the present technology.FIGs. 4A-D are schematic illustrations of the reactor module of the system of FIG. 2 with different heat exchange solutions, according to embodiments of the present technology.FIGs. 5A-C are schematic illustrations of different configurations of a housing of the reactor module of the system of FIG. 2, according to embodiments of the present technology.FIGs. 6A-B are schematic illustrations of the reactor module of the system of FIG. 2 with different recirculation mechanisms, according to embodiments of the present technology.FIG. 7 is the reactor module of the system of FIG. 2 with a direction of the reducing fluid flowillustrated, according to embodiments of the present technology.FIG. 8 is the reactor module of the system of FIG. 2 connected to a generator, according to embodiments of the present technology.FIG. 9A-B are schematic illustrations of a plurality of the reactor modules of the system of FIG. 2 connected in a modular configuration (parallel and series, respectively), according to embodiments of the present technology.FIG. 10 is a flow chart showing a method for releasing energy, according to embodiments of the present technology.FIG. 11 is a graph showing a relationship between pressure drop and time for an example regenerable fuel comprising iron and alumina particles in an example reactor module during energy production (Example 1), according to embodiments of the present technology.FIG. 12 are graphs, for an example regenerable fuel comprising iron and alumina particles in an example reactor module during energy production (Example 2) showing measured mass increase during oxidation versus what a full conversion of iron to FesC would have effected, mass decrease during reduction versus mass increase in preceding oxidation, and maximum temperature measured at the outlet of the reactor during oxidation in each cycle, according to embodiments of the present technology.DETAILED DESCRIPTION

[0056] Various aspects of the present disclosure generally address one or more of the problems associated with energy production.

[0057] Broadly, according to embodiments of the present technology, the present disclosure describes regenerable fuel, and systems and methods for releasing energy which uses the regenerable fuel. The released energy is thermal energy which can then be converted to other forms of energy if desired. The regenerable fuel is configured to be combustible, such as in a reactor module, to release thermal energy, as well as being regenerable in that after it has been used up during thermal energy generation, it can be recharged using, for example, a reduction process. In certain embodiments, the recharging can be performed in situ without requiring removal, smelting or other industrial facilities.Regenerable fuel

[0058] With reference to FIGs. 1A and IB, the regenerable fuel 10 comprises a first component 12 and a second component 14. The first and second components 12, 14 may be mechanically mixed together, or be combined in any other manner. The first component 12 can comprise any material which is oxidizable in the presence of an oxidizing fluid to generate thermal energy through combustion. The first component 12 may thus be considered as an energy carrier. Preferably, the first component 12 is also made of a material whose oxidized state can be reduced using a reducing fluid, to thereby “regenerate” the material such that it can be re-oxidized. By “regenerate” is meant to reverse some or all of the oxidation of the first component 12.

[0059] Oxidizing fluid may comprise air or any other oxygen-containing gas. Oxidizing fluid may also include certain oxygen containing liquids. Examples of oxidizing fluids comprise air, mixtures of air and inert gases (e.g. helium, argon), hydrogen peroxide, and nitrous oxide. Reducing fluid may comprise hydrogen gas, a hydrogen containing gas, a hydrocarbon containing gas or a carbon containing gas, synthesis gas (syngas), coke oven gas, producer gas, and other industrial equivalents.

[0060] The second component 14 can comprise any material configured to modulate a volumetric thermal energy production rate by the first component 12 during oxidization and / or modulate heat transfer between parts of the first component 12 during oxidization. The regenerable fuel is thus configured such that in the presence of oxidizing fluid, the first component 12 can combust whilst avoiding melting.First component

[0061] In certain embodiments, the first component 12 comprises a metallic material. Any metallic material which can combust in the presence of an oxidizing fluid can be used. In certain embodiments, the metallic material comprises iron and / or an iron containing material. Examples of iron containing materials comprise ferrous metals (e.g. steels), ferroalloys (e.g. ferronickel, ferrotitanium). In certain other embodiments, the first component 12 comprises one or more of: silicon, aluminum, magnesium, boron, zinc, lithium, sodium, titanium, nickel, manganese, zirconium and their alloys.

[0062] The first component 12 may have any suitable configuration permitting it to be housed in a reactor module and permitting fluid flow therethrough. In some embodiments, the first component 12 comprises a plurality of particles. The particles may be discrete pieces. The particlesmay have any shape, such as but not limited to: regular, irregular, flake-like, plates, spherical, rodlike, fibre, wire-like, grid-like etc. The particles may also have any suitable texture, such as but not limited to: smooth, rough, porous, solid. In one example, the first component 12 comprises iron particles with a flake-like configuration and a porous texture. In some examples, the iron particles have a size range between about 50 to about 850 microns.

[0063] In certain embodiments, the first component 12 comprises irregular shaped particles, for example flake-like particles. Compared to regular shaped particles (e.g. spherical), particles of irregular shape may avoid or reduce a sintering effect which can prolong a lifetime of the regenerable fuel.

[0064] In certain embodiments, the first component 12 comprises porous particles. Advantageously, porous particles have a larger surface area compared to particles of equivalent volume but without pores which can provide efficiencies in oxidation and reduction reactivity. In some examples, the first component 12 comprised sponge iron powder having a flake-like structure and an apparent density between about 1 and about 1.5 g / cc.Second component

[0065] In certain embodiments, the second component 14 comprises any material which can modulate a volumetric thermal energy production rate by the first component 12 and / or modulate heat transfer between parts of the first component 12. The second component 14 can be made from a material which is chemically inert in the oxidizing fluid. In some embodiments, the second component 14 functions to provide a physical separation between the particles of the first component 12.

[0066] In certain embodiments, the second component 14 comprises a ceramic material such as alumina, zirconia or silica. Other ceramic materials are also within the scope of the present technology. In some examples, the second component 14 is inert in the presence of the first component 12. In other examples, the second component 14 may interact with the first component 12.

[0067] The second component 14 may have any suitable configuration permitting it to be housed in the reactor module and permitting its physical contact or proximity with the first component 12. In some embodiments, the second component 14 comprises a plurality of particles. The particles are discrete pieces. The particles may have any shape, such as but not limited to:regular, irregular, flake-like, plates, spherical, rod-like, fibre, wire-like, grid-like. The particles may also have any suitable texture, such as but not limited to: smooth, rough, porous, solid. In one example, the second component comprises alumina particles.

[0068] As mentioned above, the first and second components 12, 14 can have any suitable configuration, texture and size such that a thermal interaction between the first and second components 12, 14 permits modulation of a volumetric thermal energy production rate by the first component 12 in the reactor module and / or modulation of heat transfer between parts, such as particles, of the first component 12.

[0069] Without being bound to theory, Developers of the present technology have noted that combustion of a metallic material in a reactor module, depending on the type of reactor module, can give rise to a temperature gradient, or temperature hot-spots. For example, in some embodiments, a core area of a reactor module could be hotter than an outer area. This can result in melting of the metallic material which is undesirable because it can render the metallic material non-reusable, and therefore the fuel non-regenerable. Melting within the fuel can also create channels which function as preferred passages for the oxidizing fluid and the reducing fluid, thereby leading to non-uniform oxidation and reduction. Developers have discovered that using a second component, alongside the first component, such as a ceramic and which has the properties described herein significantly decreases the temperature gradient and avoids or reduces melting of the metallic material. This can permit combustion at high temperatures with reduced or no melting and / or with reduced or no channel formations.

[0070] Within that context, it will be appreciated that many different configurations of the first and second components 12, 14 are within the scope of the present technology. Some nonlimiting examples are illustrated in FIG. IB.

[0071] The first and second components 12, 14 may each comprise a plurality of particles. The particles of the first component 12 may be same or different than the particles of the second component 14. For example, the particles of the second component 14 may be smaller than the particles of the first component 12. The particles may comprise a powder configuration. A size range and shape of the particles of the first and second components 12, 14 may be selected so as to prevent sintering beyond an acceptable amount and to ensure fluid passage through the first and second components.

[0072] In other embodiments, the first component 12 comprises a plurality of particles and the second component 14 comprises a coating around each of the plurality of particles of the first component.

[0073] In yet other embodiments, the second component 14 comprises a plurality of particles and the first component 12 comprises a coating around each of the plurality of particles of the second component 14. The first component 12 may be coated by the second component 14 by any suitable method, such as sol gel.

[0074] In some embodiments, the first component 12 comprises a plurality of particles on or within a mesh or other substrate of the second component 14.

[0075] In some embodiments, the second component 14 comprises a plurality of rods, and the first component 12 comprises a coating around at least a portion of the rods.

[0076] In some embodiments, the first component 12 comprises a plurality of rods, and the second component 14 comprises a coating around at least a portion of the rods.

[0077] In some embodiments, the first component 12 comprises a plurality of particles embedded within the second component 14 which is a fibrous material such as alumina wool.

[0078] In some embodiments, the first component 12 and the second component 14 each comprise a fibrous or wire-like form.

[0079] In other embodiments, the particles consist of a mixture of the first and second components 12, 14. The mixture may comprise an alloy.

[0080] The regenerable fuel 10 may therefore comprise a loose packing of particles of the first and second components 12, 14. The regenerable fuel may be provided as an insert, such as a bag, or sac of the particles. The insert may have an indistinct, or distinct form (such as cylindrical, annular or a rectangular). In other embodiments, the regenerable fuel may be disposed directly in the system.

[0081] A ratio of the second component 14 to the first component 12 can be selected such that melting of the first component 12 is avoided or kept to a predetermined minimum. In some examples, the second component 14 is about 5 to 70%, about 10 to 70%, about 10 to 67%, about 10 to 60%, about 10 to 50%, or about 20 to 50% by mass of the first component 12.

[0082] In certain embodiments, the first component 12 comprises flake-like particles ofiron and the second component 14 comprises particles of alumina. The iron particles may comprise a powder form. The alumina particles have a crystalline structure and can be referred to as “tabular alumina”. In other embodiments, calcined alumina can be used. In yet other embodiments ceramic fibres can be used. Developers have identified that spongy flake powders are easier to combust than solid spherical powders of iron. The alumina particles or other ceramic components are smaller than the iron particles. The iron particles have a diameter of about 40 to about 900 microns (20 to 325 mesh). The alumina has a diameter of about 300 microns. The ratio of the alumina - iron particles are 0-67% (by mass) and 0-60% (by volume). During combustion in the presence of the oxidizing fluid, iron is converted to iron oxide (Fe3O4). The regenerable fuel can be regenerated by contacting the iron oxide with the reducing fluid which reverts the iron oxide back to iron, ready for re-use.System

[0083] Turning now to FIG. 2, there is shown a schematic illustration of embodiments of a system 20 for releasing energy according to the present technology, and in which the regenerable fuel 10 may be used.

[0084] The system 20 comprises a reactor module 22 which is configured to house the regenerable fuel 10 and permit its combustion therein. In certain embodiments, the reactor module 22 is configured to sustain a combustion wave of the regenerable fuel 10 therein. As best seen in FIGs. 3 A-C, the reactor module 22 comprises a housing 24 defining a chamber 26 for housing the regenerable fuel 10, at least one inlet 28 through which the oxidizing fluid and / or the reducing fluid can enter the chamber 26 and react with the regenerable fuel 10, and at least one outlet 30 through fluids can exit the chamber 26. The reactor module 22 has the same or different inlets for the oxidizing fluid and the reducing fluid. The housing 24 may be elongate and disposed upright in use.

[0085] In certain embodiments, the reactor module 22 includes one or more channels 32 extending through, or alongside, the chamber 26. The one or more channels 32 are optional. In some embodiments, the one or more channels 32 are for a temperature control fluid to flow therethrough to modulate a temperature of the chamber 26 and the regenerable fuel 10 housed in the chamber 26. In other embodiments, the one or more channels 32 are for modulating (e.g., preheating) one or both of the oxidizing and reducing fluid that are configured to enter the chamber26. In the case of a chamber 26 having a circular profile, the one or more channels 32 comprises an outer sleeve around the chamber 26. The temperature control fluid may comprise any gas or any liquid. The system 20 may also include a temperature control fluid source 39 including a mechanism for its control. One or more temperature sensors (not shown) may also be included for measuring a temperature of the temperature control fluid, the oxidizing and / or reducing fluid, the fuel and / or the chamber 26. Instead of, or in addition to, the one or more channels 32, there may be provided one or more heaters around the housing 24 for modulating the temperature of the temperature control fluid, the oxidizing and / or reducing fluid.

[0086] The flow of the temperature control fluid in the one or more channels 32 may have any configuration. As illustrated in FIGs. 3 A-C respectively, the flow of the temperature control fluid may be counter to the flow of the oxidizing fluid, aligned with the oxidizing fluid flow or be a cross-flow.

[0087] In certain embodiments, the reactor module 22 comprises a packed bed reactor having the housing 24 defining the chamber 26 which houses the regenerable fuel 10 which is packed therein. In certain embodiments, the housing 24 is made of a metallic material, such as steel. Other materials for the housing 24 are within the scope of the present technology.

[0088] Heat transfer to and / or from the temperature control fluid in the channels 32 may be modulated in any manner. Certain non-limiting examples are shown in FIGs. 4A-C.

[0089] In certain embodiments, there is provided a transfer material 25 between the regenerable fuel 10 and the housing 24 (FIG. 4A). The transfer material may comprise fibres (top image in FIG. 4A), balls / particles (middle image in FIG. 4A), and mesh form (bottom image in FIG. 4A).

[0090] In certain embodiments, the housing 24 may include heat transfer elements 27, such as fins (FIG. 4B) for modulating a heat transfer rate from the channel 32. In other examples, the heat transfer elements may have a configuration different than fins.

[0091] In certain embodiments, the channel 32 may be modified to allow a longer residence time of the temperature control fluid. As best seen in FIG. 4C, the channel 32 may have a spiral form, amongst other possible configurations.

[0092] In certain embodiments, there is provided a filler material 29 which may comprise an expandable material and / or a compressed material (FIG. 4D). Thereby, any gaps created due tomorphological changes of the regenerable fuel 10 will be filled, thereby preventing separation of the regenerable fuel 10 and the housing 24. The filler material 29 may comprise a mesh or a foam. The filler material 29 comprises a material which is inert in oxygen and does not melt at the temperatures under which the reactor module operates. In certain embodiments, the filler material 29 is made of a ceramic such as one or more of: alumina, zirconia or silica. The filler material 29 may comprise a ceramic adhesive which can be applied to the internal wall(s) of the housing 24 and to which the first component can adhere resulting in minimization or avoidance of gaps. In other embodiments, the filler material 29 may comprise a ceramic liner (such as a ceramic liner with a thickness of about 1 / 8 inch) which can be used to line the internal wall(s) of the housing 24. In yet other embodiments, a ceramic liner can be used to wrap the first component.

[0093] A configuration of the reactor module 22 and / or housing, and hence the regenerable fuel disposed therein, may have any suitable configuration. Example configurations are illustrated in FIGs. 5A-5C and include cylindrical (FIG. 5 A), annular (FIG. 5B) and rectangular (FIG. 5C).

[0094] The one or more inlets 28 for the oxidizing fluid may be positioned at an end of the chamber 26 of the reactor module 22 so that the oxidizing fluid is caused to flow longitudinally along the chamber 26. In other embodiments, the one or more inlets 28 for the oxidizing fluid may comprise porous channels through which the oxidizing fluid can be caused to flow transversely across the chamber 26.

[0095] Referring back to FIG. 2, the system 20 may further include an oxidizing fluid source 34, for providing the oxidizing fluid, fluidly connected to the chamber 26 through the one or more inlets 28. An energy source 36 may be provided as an activation energy for the combustion by one or both of: heating the oxidizing fluid, or by heating the regenerable fuel 10 (such as through the one or more channels 32). The energy source 36 may comprise a heater such as a resistive heater, an induction heater, or the like. A blower (not shown) may be provided for pushing the oxidizing fluid into the chamber 26. The oxidizing fluid may comprise air.

[0096] In certain embodiments, the oxidizing fluid may be preheated by circulation of the oxidizing fluid (FIGs. 6A and 6B). The temperature control fluid can be re-circulated. Cold oxidizing fluid is introduced into the channel 32 at the outlet end and caused to flow along the channel 32 while the regenerable fuel 10 is combusting which causes the oxidizing fluid to become heated. The heated oxidizing fluid is then caused to flow through the inlet 28 and contact theregenerable fuel 10 for continued combustion.

[0097] As seen in FIG. 2, the system 20 may further include a reducing fluid source 37, for providing the reducing fluid, fluidly connected to the chamber 26 through the one or more inlets 28. The reducing fluid may comprise hydrogen gas. Steam may be removed from the hydrogen gas via cooling or absorption for an increase in an efficiency of the recharging.

[0098] FIG. 7 illustrates the flow of the reducing fluid during recharging of the regenerable fuel 10. The reducing fluid is caused to flow through the inlet 28 and contact the regenerable fuel 10. In alternative embodiments, the reducing fluid can also be caused to flow through the outlet 30 towards the one or more inlets 28. It is not particularly limited how the reducing fluid is caused to contact the regenerable fuel 10. In some embodiments, the reduction process operates at a temperature of between about 500 degC and about 700 degC. This temperature range can be achieved in the reactor module 22 using one or more heaters (such as the heaters used to heat the fuel or the oxidizing fluid). Alternatively, the reducing fluid may be heated, such as by burning a hydrogen-air mixture under fuel rich conditions and using the heated hydrogen as the reducing fluid. One or more sensors (not shown) may be provided for detecting a composition or concentration of the reducing fluid in order to assess a completeness of the reduction of the first component. For example, the reduction could be deemed complete when the concentration of hydrogen in the exhaust is detected to have reached a predetermined concentration. In other embodiments, the reduction could be determined to be complete when a pressure difference across the reactor module 22 reduces or stops decreasing. The stopping of the recharging step may thus be automated.

[0099] The system 20 further comprises, in certain embodiments, a fluid modulator (not shown) for modulating a flow rate of the oxidizing fluid and / or the reducing fluid. The fluid modulator can also cause flow of the oxidizing fluid and / or the reducing fluid to stop and start. Different fluid modulators may be provided for each of the oxidizing fluid and the reducing fluid, which may be termed “oxidizing fluid modulator” and “reducing fluid modulator” respectively.

[0100] In use, the regenerable fuel 10 housed in the chamber 26 is pre-heated (before combustion), by one or both of the heated oxidizing fluid and direct heating of the regenerable fuel 10 (e.g. by a heater or by the temperature control fluid). As the oxidizing fluid flows from one end of the chamber 26 towards the other end, the first component 12 combusts and presents acombustion front that moves upwardly. During combustion, the first component 12 oxidizes whilst the oxidizing fluid is reduced. This is an exothermic reaction and further heats the reduced oxidizing fluid. The reduced and heated oxidizing fluid flows through the chamber 26 and out of the outlet 30. During recharging, the reducing fluid is caused to flow through the regenerable fuel 10.

[0101] As best seen in FIGs. 2 and 8, the outlet 30 can be connected to a generator 38 for converting the heated fluid to another energy form, such as one or more of electricity, steam and light. Example generators 38 include, but are not limited to, a Stirling engine, a steam engine, a thermoelectric generator, and the like. Any residual heat can be used for space heating, combined heat and power systems, and / or be exhausted into the atmosphere.

[0102] The rate of combustion of the regenerable fuel 10, and hence a rate of thermal energy output, can be controlled by one or more of (i) modulating a flow rate of the oxidizing fluid, (ii) modulating a ratio of the second component 14 to total first and second components 12, 14 (reducing a fraction of the second component 14 increases the volumetric rate of thermal energy generation in the mixture), (iii) modulating a temperature of the oxidizing fluid, (iv) modulating a pressure in the reactor module 22, and (v) modulating a volume or a mass of the regenerable fuel 10.

[0103] Developers have identified that increasing a flow rate of the oxidizing fluid can increase a speed of the combustion wave and can also increase a temperature of the combustion. Developers have also identified that increasing a pressure in the reactor module 22 can increase a rate of the combustion and hence a rate of energy production. Developers have also identified that increasing the temperature of the oxidizing fluid can increase a rate of the combustion and hence a rate of energy production.

[0104] An energy output of the system 20 can be controlled by (i) modulating a flow rate of the oxidizing fluid, (ii) modulating a volume or a mass ratio of the second component 14 to total first and second components 12, 14 (reducing the second component 14 increases the energy output), (iii) modulating a temperature of the preheating of the oxidizing fluid, (iv) modulating a preheating temperature of the fuel; and (v) modulating an amount of the fuel.

[0105] In this respect, it will be appreciated that increasing the amount of fuel which combusts increases the energy output. The fuel can be increased by enlarging a capacity of thereactor module 22, such as by increasing a diameter, a length or any other dimension of the housing for the fuel. This solution provides a controllable energy potential.

[0106] It will also be appreciated the rate of combustion and / or the energy output of the system 20 can be selectively dynamically adjusted, which may prove to be beneficial in various situations, for example, where a need for energy quickly increases or decreases. For example, the rate of combustion and / or energy output can be dynamically changed (i.e., during oxidation or reduction) by (i) modulating a flow rate of the oxidizing fluid or the reducing fluid, (ii) modulating a temperature of the oxidizing fluid, the reducing fluid and / or the fuel, and (iii) modulating a pressure in the reactor module 22.

[0107] In certain embodiments, an energy storage capacity of the system 20 can be controlled by providing a plurality of reactor modules 22 which are selectively connectable together to vary the amount of fuel, and hence the amount of stored energy. The plurality of reactor modules 22 are fluidly connectable as an array. The plurality of reactor modules 22 may be connected in parallel and / or in series. More specifically, when the plurality of reactor modules 22 are fluidly connected in series, the combustion front will move from one reactor module 22 to another reactor module 22 consecutively. When the plurality of reactor modules 22 are fluidly connected in parallel, there will be a combustion front in each of the reactor modules 22 which can move substantially simultaneously to one another, which can increase output power. FIG. 5C and 9A illustrate an example embodiment in which the system 20 comprises four reactor modules 22 which share a common inlet and a common outlet. Any of the four reactor modules 22 can be disconnected from the system 20 to control the power outage. The reactor modules 22 that remain connected, will undergo fuel combustion and thermal energy generation at the same time. It will be appreciated that such a modular system 20 can include any number of reactor modules 22.

[0108] In certain embodiments, the modularity may also apply to the channels 32 through which temperature control fluid flows. Some embodiments may consist of a single channel 32 surrounding all the chambers 26, or the channels can be split, with, for example each channel 32 surrounding (or being surrounded by, in the annular reactor case) a single chamber 26. The channels can be placed in parallel, in series, or in any complex configuration that would optimize heat transfer through them.Method

[0109] Referring now to FIG. 10, according to a broad aspect, there is also provided a method 50 for releasing energy. The method 50 comprises providing a regenerable fuel, such as the regenerable fuel 10, in a reactor module, such as the reactor module 22. The regenerable fuel includes the first component 12 and the second component 14, the first component 12 being oxidizable by the oxidizing fluid to release the energy through combustion, and the second component 14 being configured to modulate a volumetric energy production rate by the first component 12 and / or modulate energy transfer between parts of the first component 12; and causing oxidation of the first component 12 by supplying activating energy and the oxidizing fluid into the reactor module 22 to generate energy through combustion of the fuel 10. The activating energy may be provided by heating the oxidizing fluid and / or by heating the fuel.

[0110] In certain embodiments, a ratio of the first and second components 12, 14 are such that melting of the first component 12 is avoided during combustion. The method 50 comprises modulating one or more of a flow of the oxidizing fluid, a pressure in the reactor module 22 and a rate of the energy supplied such that melting of the first component 12 is avoided during combustion.

[0111] The method 50 may further comprise modulating a rate of the energy release by modulating at least one of: a flow rate of the oxidizing fluid at the inlet 28 of the reactor module 22, a temperature of the oxidizing fluid, a temperature of the fuel, and a pressure in the reactor module 22. Advantageously, the system permits fine control of the energy release, which control may be instantaneous or close to instantaneous.

[0112] The method 50 may further comprise stopping the flow of the oxidizing fluid into the reactor module 22 to cause stoppage of the energy release.

[0113] The method 50 may further comprise restarting the energy release by restarting the flow of the oxidizing fluid into the reactor module 22. The restarting may be instantaneous or substantially instantaneous while heat remains in the system 20. A heat remaining in the system may comprise a predetermined heat, below which additional heat may need to be supplied to restart the energy release.

[0114] The method 50 may further comprise supplying a reducing fluid into the reactor module 22 to regenerate the fuel 10.

[0115] The supplying the reducing fluid may be automated by detecting a composition orconcentration of the reducing fluid after it has flowed through the fuel 10 and / or a pressure across the reactor module, and in response to the concentration meeting or being greater than a predetermined threshold, stopping supply of the reducing fluid into the reactor module 22.

[0116] The method 50 may further comprise harnessing the released energy and converting it to electricity or any other form of energy.ExamplesExample 1

[0117] The fuel 10 comprised a first component 12 which was iron power with a spongy flake structure having a size distribution of about 50-850 micron. The second component 14 was alumina particles which was mechanically mixed with the first component 12. The size distribution of the second component 14 was 300 micron diameter. The lab-scale reactor module 22 comprised a housing of a packed bed reactor which was cylindrical and had a length of about 12 cm and a diameter of about 1.9 cm. The housing defined the chamber 26 in which was packed the particulate fuel 10. Electric heaters were disposed around the housing to pre-heat the fuel. The heaters were controlled by a thermocouple to around 500degC.

[0118] The reactor module 22 was positioned upright. Air was used as the oxidizing fluid and was caused to flow into the pre-heated chamber from a bottom of chamber. At an airflow rate of 5 cc / s, no combustion zone was observed. At 10 cc / s, an orange zone (combustion front) was observed which moved from the bottom of the chamber to the top of the chamber. At 15 cc / s, an orange zone was also observed, which moved from the bottom of the chamber to the top of the chamber, and higher temperatures than at lOcc / s were observed.

[0119] With no second component in the fuel powder, iron powder melting was observed which created channels in the packed fuel leading to incomplete oxidation and reduction. With a second component (ceramic particles), this was avoided. Table 1 shows the effect of different amounts of ceramic component in the iron bed.

[0120] Table 1 : Effect of introducing ceramic particles into the iron powder bed with 10 cc / s airflow rate.

[0121] Also the pressure drop was investigated and it was found that the pressure drop increases over time of combustion. Furthermore, the pressure drop is increased as the amount of ceramic particles (second component) is increased (FIG. 11).

[0122] It is reasonably expected that this lab scale system set up for releasing energy can readily be scaled up. It will also be appreciated that similar results can be expected using different first and second components in the fuel.Example 2

[0123] The fuel 10 comprised a first component 12 which was iron power with a spongy flake structure and having a size distribution of about 45-850 microns. The second component 14 was tabular alumina particles having a size distribution of about 300 microns and which was mechanically mixed with the first component 12 at a ratio of 1 : 1. The lab-scale reactor module 22 comprised a housing of a packed bed reactor which was cylindrical and had a length of about 16 cm. The housing defined the chamber 26 in which was packed the particulate fuel 10. Ceramic heaters were disposed around the housing for heating during reduction. A nozzle heater was provided at a bottom of the reactor for initiating combustion. As seen in Fig. 12, multiple cycles (xlO) of storing and releasing energy were achieved without loss of energy release. In Fig.12, the first graph shows the efficiency of each cycle (i.e., measured mass increase during oxidation versus what a full conversion of iron to FesC would have effected), the second graph shows the reduction efficiency for each cycle (mass decrease during reduction versus mass increase in precedingoxidation), and the maximum temperature measured at the outlet of the reactor during oxidation in each cycle. The multiple cycling functionality can also be reasonably expected in a scaled-up reactor.

[0124] Those of ordinary skill in the art will realize that the description of the fuel, systems and methods for storing and / or releasing energy are illustrative only and are not intended to be in any way limiting. Other embodiments will readily suggest themselves to such persons with ordinary skill in the art having the benefit of the present disclosure. In the interest of clarity, not all of the routine features of the implementations of the system and method are shown and described. In particular, combinations of features are not limited to those presented in the foregoing description as combinations of elements listed in the appended claims form an integral part of the present disclosure. It will, of course, be appreciated that in the development of any such actual implementation of the system and method numerous implementation-specific decisions may need to be made in order to achieve the developer’s specific goals, such as compliance with application- related, system-related, and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the field of energy storage / energy conversion / energy release / catalytic conversion / reactor design having the benefit of the present disclosure.

[0125] The present disclosure has been described in the foregoing specification by means of non-restrictive illustrative embodiments provided as examples. These illustrative embodiments may be modified at will. The scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

CLAIMS:What is claimed is:

1. A system for releasing energy, the system comprising: at least one reactor module having an inlet connectable to an oxidizing fluid source; and a regenerable fuel disposed in the at least one reactor module, the regenerable fuel including a first component and a second component, the first component being oxidizable by the oxidizing fluid to release the energy, and the second component being configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component.

2. The system of claim 1, wherein the first component comprises a metallic material.

3. The system of claim 2, wherein the metallic material comprises iron and / or an iron-containing material.

4. The system of any one of claims 1 to 3, wherein the second component is made from a material which is chemically inert in the oxidizing fluid.

5. The system of any one of claims 1 to 4, wherein the second component comprises a ceramic.

6. The system of any one of claims 1 to 5, wherein one or both of the first component and the second component comprises at least one of: particles, powder, coatings, and a substrate.

7. The system of any one of claims 1 to 6, wherein the oxidizing fluid comprises oxygen and / or an oxygen containing fluid.

8. The system of any one of claims 1 to 7, further comprising a fluid modulator for modulating a fluid flow through the inlet.

9. The system of any one of claims 1 to 8, wherein the at least one reactor module comprises at least one packed bed reactor.

10. The system of claim 9, wherein the at least one packed bed reactor comprises a plurality of packed bed reactors which are fluidly connectable in series or in parallel.

11. The system of any one of claims 1 to 10, wherein the at least one reactor module, has a cylindrical configuration, an annular configuration or a rectangular configuration.

12. The system of any one of claims 1 to 11, further comprising the oxidizing fluid source.

13. The system of any one of claims 1 to 12, further comprising a heater for providing energy to the regenerable fuel and / or the oxidizing fluid source.

14. The system of any one of claims 1 to 13, further comprising a reducing fluid source fluidly connected to the at least one reactor module for providing reducing fluid to the regenerable fuel.

15. The system of claim 14, wherein the reducing fluid comprises hydrogen, a hydrogen containing fluid, a hydrocarbon containing fluid or a carbon containing fluid.

16. The system of any one of claims 1 to 15, further comprising a sensor at an outlet of the at least one reactor module for sensing a concentration of at least a component of a fluid at the outlet.

17. The system of any one of claims 1 to 16, further comprising a generator operatively connected to an outlet of the at least one reactor module for converting the released energy to at least one of: electricity, steam, and light.

18. The system of any one of claims 1 to 17, further comprising a filler material between the regenerable fuel and the housing for minimizing or avoiding separation of the regenerable fuel and the housing.

19. An electricity generator comprising: the system of any one of claims 1 to 18; and a heat engine drivingly connected to the system, the heat engine being operable to generate electricity from the released energy provided by the reactor.

20. A method for releasing energy, the method comprising: providing a regenerable fuel in a reactor module, the regenerable fuel including a first component and a second component, the first component being oxidizable by an oxidizing fluid to generate the energy, and the second component being configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component; andcausing oxidation of the first component by supplying input energy and the oxidizing fluid into the reactor module to releasing the energy through combustion.

21. The method of claim 20, further comprising modulating a rate of energy release by modulating at least one of: a flow rate of the oxidizing fluid at an inlet of the reactor module, a temperature of the oxidizing fluid, a pressure in the reactor module; a temperature of the reducing fluid; and a temperature control fluid which can cause a heat exchange with the regenerable fuel.

22. The method of claim 21, wherein increasing or reducing at least one of: the flow rate of the oxidizing fluid at the inlet of the reactor module and the pressure in the reactor module causes an increase or reduction, respectively, in the rate of energy release.

23. The method of claim 21 or claim 22, further comprising stopping the flow of the oxidizing fluid into the reactor module to cause stoppage of energy release.

24. The method of claim 23, further comprising restarting the flow of the oxidizing fluid into the reactor module to restart the energy release.

25. The method of any one of claims 21 to 24, further comprising supplying a reducing fluid into the reactor module to regenerate the regenerable fuel.

26. The method of claim 25, further comprising: sensing a concentration of at least a component of the reducing fluid at an outlet of the reactor module; and in response to the concentration meeting or being greater than a predetermined threshold, stopping supply of the reducing fluid into the reactor module; or detecting a pressure difference across the reactor module and in response to the pressure difference being less than a predetermined threshold, stopping supply of the reducing fluid into the reactor module.

27. The method of any one of claims 21 to 26, wherein the supplying the energy comprises heating the regenerable fuel.

28. The method of any one of claims 21 to 27, wherein the supplying the energy comprises heating the oxidizing fluid.

29. The method of any one of claims 21 to 28, further comprising harnessing the released energy to drive an engine.

30. The method of any one of claims 21 to 29, further comprising converting the released energy to electricity.

31. The method of any one of claims 21 to 28, wherein the first component comprises a metallic material.

32. The method of claim 31, wherein the metallic material comprises iron and / or iron containing material.

33. The method of any one of claims 21 to 32, wherein the second component is made from a material which is chemically inert in the oxidizing fluid.

34. The method of any one of claims 21 to 33, wherein the second component comprises a ceramic.

35. The method of any one of claims 21 to 34, wherein one or both of the first component and the second component comprises at least one of: particles, powder, coatings, and a substrate.

36. The method of any one of claims 21 to 35, wherein the oxidizing fluid comprises oxygen and / or an oxygen containing fluid.

37. The method of any one of claims 21 to 36, wherein the reducing fluid comprises hydrogen, a hydrogen containing fluid, a hydrocarbon including fluid or a carbon containing fluid.

38. A regenerable fuel comprising: a first component oxidizable by an oxidizing fluid to release thermal energy; and a second component configured to modulate a volumetric energy production rate by the first component and / or modulate energy transfer between parts of the first component.

39. The regenerable fuel of claim 38, wherein the first component comprises a metallic material, and optionally the metallic material is in the form of a powder.

40. The regenerable fuel of claim 39, wherein the metallic material comprises iron and / or iron containing material.

41. The regenerable fuel of any one of claims 38 to 40, wherein the second component is made from a material which is chemically inert in the oxidizing fluid.

42. The regenerable fuel of any one of claims 38 to 41, wherein the second component comprises a ceramic.

Images