WO2011116141A2

WO2011116141A2 - Clean steel production process using carbon-free renewable energy source

Info

Publication number: WO2011116141A2
Application number: PCT/US2011/028737
Authority: WO
Inventors: Victor Joseph; Amjiad Huda; Pia A. Victor; Joy J Victor
Original assignee: Sun Hydrogen, Inc.
Priority date: 2010-03-18
Filing date: 2011-03-16
Publication date: 2011-09-22
Also published as: WO2011116141A3

Abstract

Systems and methods for producing steel comprise using a renewable energy source, such as solar energy, to heat a heat-releasing energy storage medium, such as MgF₂. Heat from the heat-releasing energy storage medium is used to generate steam from liquid water. Next, H₂ and O₂ are generated from steam via electrolysis or direct thermal decomposition at >2400°C. The energy required for the electrolysis of steam may be provided from one or more renewable energy sources, such as one or more wind turbines and/or fuel cells. A fraction of the H₂ and O₂ formed via electrolysis is used to generate oxy-hydrogen, which is subsequently used to form steel in an oxy-hydrogen steel smelter. The oxy-hydrogen steel smelter uses iron formed in a hydrogen-based blast furnace, which uses H₂ formed from the dissociation of water to reduce iron oxide.

Description

CLEAN STEEL PRODUCTION PROCESS USING CARBON-FREE

RENEWABLE ENERGY SOURCE

CROSS-REFERENCE

[0001] This applications claims priority from U.S. Provisional Patent Application Serial Nos.

61/315,362, filed on March 18, 2010, 61/385,538, filed on September 22, 2010, and 61/438,498, filed on February 1, 2011, which are entirely incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Steel is a metal alloy comprising iron and carbon. Steel is typically produced in a two-stage process. In a first stage, iron ore is reduced or smelted with coke and limestone in a blast furnace, producing molten iron, which is either cast into pig iron or carried to the next stage as molten iron. In a second stage, known as steelmaking, impurities such as sulfur, phosphorus, and excess carbon are removed, and alloying elements, such as manganese, nickel, chromium and vanadium, are added to produce steel having a desired steel composition.

[0003] Steel may be formed using an integrated steel mill. The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke). These materials are charged in batches into a blast furnace where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into pig iron or directed to other vessels for further steelmaking operations. Next, molten steel is cast into large blocks. During the casting process, various methods may be used, such as the addition of aluminum, so that impurities in the steel float to the surface where they may be cut off the final product.

SUMMARY OF THE INVENTION

[0004] In an aspect of the invention, a system for forming steel comprises a heat exchanger for generating steam from liquid water with the aid of energy provided by a carbon- free renewable energy source. The system may further include a hydrogen generator downstream from the heat exchanger, the hydrogen generator for generating hydrogen (H₂) and oxygen (0₂) from steam. A steel smelter downstream from the hydrogen reactor may be used for generating steel with the aid of H₂ and 0₂ formed in the hydrogen generator.

[0005] In another aspect of the invention, a method for forming steel comprises generating steam from liquid water with the aid of energy provided by a renewable energy source. Next, hydrogen (H₂) and oxygen (0₂) may be generated from steam Steel may subsequently be formed in a steel smelter using iron from a hydrogen-based blast furnace. Steel may be generated with the aid of the H₂ and 0₂ generated from steam.

[0006] In an embodiment, a method for forming hydrogen and oxygen for use in forming steel comprises bringing N₂ or air in contact with iron oxide-containing surfaces in a hydrogen generator to form iron-containing surfaces and oxygen (0₂). Next, 0₂ may e removed from the hydrogen generator. Steam may then be brought in contact with the iron-containing surfaces in hydrogen generator to form iron oxide-containing surfaces and hydrogen (H₂). The steam may generated with the aid of energy from a carbon- free renewable energy source. H₂ from the hydrogen generator may then be removed. Next, H₂ and 0₂ may be used to generate steel using a steel smelter.

INCORPORATION BY REFERENCE

[0007] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0009] FIG. 1 A shows a high-level depiction of a steel production system, in accordance with an embodiment of the invention; FIG. IB shows a high-level depiction of a steel production system, in accordance with an embodiment of the invention;

[0010] FIG. 2 shows a process flow diagram, in accordance with an embodiment of the invention;

[0011] FIG. 3 schematically illustrates a system for producing steel, in accordance with an embodiment of the invention;

[0012] FIG. 4 schematically illustrates a high temperature steam electrolysis system, in accordance with en embodiment of the invention;

[0013] FIG. 5 schematically illustrates a proton exchange membrane (PEM) fuel cell, in accordance with an embodiment of the invention;

[0014] FIG. 6 schematically illustrates a solid oxide fuel cell (SOFC), in accordance with an embodiment of the invention;

[0015] FIG. 7 schematically illustrates an iron-smelting vessel, in accordance with an embodiment of the invention;

[0016] FIG. 8 shows a pivoted horizontal paraboloidal solar dish with motorized dual axis tracker, in accordance with an embodiment of the invention;

[0017] FIG. 9 shows a system for generating hydrogen and oxygen (for steel production, for example), the system having a paraboloidal dome, in accordance with an embodiment of the invention;

[0018] FIG. 10 shows a system for generating hydrogen and oxygen, the system having a solar dish, in accordance with an embodiment of the invention;

[0019] FIG. 11 shows a system for generating hydrogen and oxygen, the system having an electrolyzer, in accordance with an embodiment of the invention; [0020] FIG. 12 shows a system for generating hydrogen and oxygen, the system having a fluidized bed reactor ("FBR"), in accordance with an embodiment of the invention;

[0021] FIG. 13 shows a fluidized bed reactor, in accordance with an embodiment of the invention; and

[0022] FIG. 14A shows intersecting planes forming reactive surfaces for use in a shell-and-tube reactor, in accordance with an embodiment of the invention; FIG. 14B shows a tube-in-tube configuration for use in a shell-and-tube reactor, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] While preferable embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only.

Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention.

[0024] There are various problems associated with current methods and systems for forming steel. For example, a major environmental hazard associated with integrated steel mills is the pollution produced in the manufacture of coke, which is an essential intermediate product in the reduction of iron ore in a blast furnace. As another example, the energy cost and structural stress associated with heating and cooling a blast furnace requires primary steelmaking vessels to operate on a continuous production campaign of several years duration, leading to considerable energy costs. Even during periods of low steel demand, it may not be feasible to let the blast furnace grow cold.

[0025] A drawback of current steel smelting is that it may be an energy intensive process, leading to considerable emissions in greenhouse gases that may exacerbate global warming, in addition to other pollutants, such as NO_x (e.g., NO, N0₂) and SO_x (e.g., S0₂), that may have adverse health and environmental effects. Smelting may be a major contributor of anthropogenic sulfur dioxide emissions. Sulfur dioxide may be oxidized in the atmosphere to sulfuric acid, which may be returned to ground level as acid rain. Acid rain may have harmful effects on plants, aquatic animals and infrastructure. In addition, energy intensive steel smelting operations may increase the dependence on a relatively limited supply of fossil fuels.

[0026] The invention provides systems and methods that may advantageously reduce, if not eliminate, the drawbacks of current steel smelting processes, in addition to other processes that may require steam, hydrogen and/or oxygen as feed chemicals. Systems and processes provided herein may reduce, if not eliminate, greenhouse gas emissions, thereby reducing carbon footprint and curtailing global warming. In addition, systems and processes provided herein may reduce, if not eliminate, the dependence on fossil fuels for the energy required for generating steam and steel smelting.

[0027] The invention provides systems and methods for steel production. Various aspects of the invention described herein may be applied to any of the particular applications set forth below or for any other types of production processes utilizing renewable energy sources, such as carbon-free renewable energy sources. Carbon-free renewable energy sources may include solar radiation, wind energy, geothermal energy, wave energy. Energy may be harvested from one or more of such sources, for example, with the aid of turbines, photovoltaic solar cells and modules, and Rankine or organic Rankine cycles.

[0028] The invention may be applied as a standalone system or method, or as part of integrated steel production process, which may be provided at a concentrated location. It shall be understood that different aspects of the invention may be appreciated individually, collectively, or in combination with each other.

[0029] Systems provided herein may harvest energy from renewable energy sources and use the energy to generate steam, which may subsequently be used to generate H₂ and 0₂ that may be used for various downstream processes, such as steel smelting. A renewable energy source may be situations in close proximity to a heat exchanger for generating steam, which may advantageously preclude the need to store and transport water, hydrogen and oxygen. Since energy may be harvested locally from a renewable energy source, energy transmission losses may be reduced, if not eliminated.

[0030] Systems provided herein derive unexpected benefits from a combination of units that might not have been conceivable in traditional processes. For instance, large- volume steel smelting operations might not have realized the benefits of having H₂ and O2 generated from renewable energy sources, since the relatively large energy demands of traditional steel smelting operations may have been difficult to meet with renewable energy sources.

[0031] The combination of units provided herein, in addition to the spatial distribution of units in relation to one another, may enable efficient and environmentally friendly systems for generating ¾ and O2 for use in downstream processes, such as steel smelting. In embodiments, systems provided herein may be located in close proximity to one another, obviating the need for storage, thereby maximizing the conversion efficiency of feed reactants (e.g., H₂ and 0₂) to products and energy, which may be used to generate steel.

[0032] FIG. 1A schematically illustrates a system for forming steel, in accordance with an embodiment of the invention. The system may include an energy or heat source 010, a hydrogen generator 015 and a steel production assembly 040. The steel production assembly 040 may include a steel smelter. The hydrogen generator 015 may be for generating hydrogen (H₂), or H₂ and oxygen (0₂). The energy source 010 may include a thermal energy storage medium. In some cases, the energy source 010 may be used to heat liquid water to steam. Steam may subsequently be dissociated into H₂ with the aid of the hydrogen generator 015. In some cases, oxygen from steam may be reclaimed from the hydrogen generator 015 as 0₂.

[0033] In some instances, the hydrogen generator may be an electrolysis unit (or electrolyzer). FIG. IB shows a steel production system that may include The energy or heat source 010, an electricity source 020, an apparatus for electrolysis 030, and the steel production assembly 040. [0034] The energy source 010 may be a renewable energy sources, such as one or more of solar, geothermal, or hydroelectric energy sources. The energy source 010 may be thermally coupled to a thermal energy storage medium (see below).

[0035] For example, solar energy may directly heat a fluid used in electrolysis (e.g., H₂0), or may heat up a working fluid that in turn may be used to heat up the electrolysis fluid. In some embodiments, components such as heat exchangers, concentrating optics, or reflectors may be used. Alternative forms of heating a fluid may be used, such as those discussed elsewhere herein. In some embodiments, a renewable energy source used for heating may be supplemented with additional heating sources. A fluid may or may not be heated to a level such that a vapor is formed.

[0036] An electricity source 020 may be any source capable of providing electrical energy to run the electrolysis process. Preferably, the electricity source may include a renewable energy source, which may or may not be supplemented with additional energy sources. For example, a wind energy source may be used to produce electricity. The wind energy may or may not be supplemented with additional renewable energy sources (e.g., solar, geothermal, hydroelectric), power from a grid utility, or using stored energy.

[0037] Electrolysis 030 may occur utilizing the heated fluid heated by a heat source 010 and the energy from the electricity source 020. Preferably, high temperature steam electrolysis may be utilized in the steel production system. For instance, H₂ and O2 may be separated from steam

[0038] Following electrolysis 030, a steel production arrangement 040 may be used, which may utilize the H₂ and O2 produced from the electrolysis. A steel production arrangement may include an oxy- hydrogen flame generator, a hydrogen based blast furnace, and one or more smelter, such as an oxy- hydrogen scrap smelter and an oxy-hydrogen steel smelter. Additional details and embodiments may be discussed further elsewhere herein. Preferably, the steel production system, including the heat source, electricity source, apparatus for electrolysis, and steel production assembly may be concentrated at a location. For example, one site may be provided for all or most of the parts of the steel production system. In some embodiments, the electrolysis and steel production arrangement may be provided at the same location. Optionally, a fluid or steam source for electrolysis may be provided at the same location or nearby. Similarly, an electrical energy source may optionally be provided at the same location or nearby.

[0039] As an alternative, the electricity source 020 and apparatus for electrolysis 030 may be replaced by a hydrogen generator, such as a shell-and-tube hydrogen reactor or a fluidized bed reactor (see below). The hydrogen generator may generate H₂ from steam. The hydrogen generator may also generate 0₂.

[0040] Systems and methods provided herein may be based at least in part on the realization that generating H₂ and 0₂ from steam may be more efficient than generating H₂ and 0₂ from liquid water. In some embodiments, solar radiation is used to generate steam, which may be subsequently dissociated into H₂ and 0₂. H₂ and 0₂ may then used to produce steel.

[0041] One issue with using solar energy in commercial processes is the efficiency by which heat is transferred from one medium to another. For instance, it may be desirable to use solar energy to generate steam, but the transfer of solar energy or thermal energy upon the impingement of solar radiation on a radiative surface to generate water using current heat exchangers may be an inefficient process in some circumstances. One solution is to use large radiative surfaces to collect more solar energy, which leads to the loss of usable space and an increase in materials cost. Another solution is to use a heat exchanger having a large number of heat transfer coils, but this solution may lead to high material costs and the loss of usable space, as large heat exchangers are required.

[0042] Another issue with transferring solar radiation to water is that current heat transfer systems and methods may not be able to provide for the efficient transfer of energy. As an example, to transfer solar energy to water, solar energy would have to be transferred to one or more intermediate mediums. If a solar collector is not disposed in the vicinity of the heat exchanger, this solution may be impractical as the transmission of energy over larger distances may lead to losses (radiative, conductive).

[0043] In some cases, solar radiation may be collected using a solar radiation collection module (or unit), such as a solar collector, that is in the vicinity of a heat exchanger for conveying energy to water. The solar radiation collection module may be utilized as part of a steel production system, e.g., as part of a heat source 010 provided in FIGs. 1 A and IB. Alternatively, it may be used with other production processes and configurations.

[0044] Methods and systems provided herein may minimize energy losses upon the transfer of solar energy to water to generate steam. In an embodiment, solar radiation is collected with the aid of a vertically stacked solar energy concentrator, which advantageously minimizes the amount of space required for a solar collector while maximizing the amount (or flux) of solar radiation captured. In an embodiment, the solar radiation collection module may be located in the vicinity of the other systems used to generate ¾ and O₂ from ¾0.

[0045] Systems and methods provided herein may enable the efficient transfer of solar energy to liquid water to generate steam when compared to other current systems and methods. In embodiments, solar energy is transferred to a heat-releasing energy storage medium (also "thermal energy storage material" herein), which is in thermal contact with liquid water. The thermal energy storage material is configured to retain solar energy and minimize losses upon the transmission of solar energy to water.

[0046] In embodiments, thermal energy is introduced into one or more quantities of a thermal energy storage material with the aid of an energy transfer medium. In an embodiment, a system utilizing this approach has hot fluid passing through pipes, which are submerged in a liquid energy-transfer medium. The medium boils and the vapors are condensed on the sides of the one or more containers filled with a thermal energy storage material. The heat of condensation causes the storage material to melt, thereby storing the thermal energy in the molten storage material. The hot fluid is generated using one or more solar collectors in the vicinity of a module hosing the thermal energy storage material. In another embodiment, a system utilizing this approach direct solar energy directly to the thermal energy storage material, which subsequently melts, thereby storing the thermal energy in the molten storage material.

[0047] In an embodiment, the thermal energy storage material is a salt. In an embodiment, the salt comprises a Group I element or a Group II element. In an embodiment, the thermal energy storage material is a binary salt. In another embodiment, the thermal energy storage material is a ternary salt. In an embodiment, the salt may have the general formula A_xB_y, wherein 'A' is a Group I or Group II element, 'B' is a halogen, and 'x' and 'y' are numbers greater than zero. In an embodiment, 'x' and 'y' are selected so as to provide a stoichiometric ratio of A and B. In an embodiment, A may be selected from the group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca and Sr, an B may be selected from the group consisting of F, CI, Br and I. In embodiments, the thermal energy storage medium may be calcium chloride, barium chloride, strontium chloride, sodium bromide, potassium bromide, magnesium bromide, sodium fluoride, potassium fluoride, magnesium fluoride, lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, strontium iodide, and mixtures (or combinations) thereof.

[0048] In an embodiment, the composition and quantity of the thermal energy storage medium is selected so as to reduce the melting point of the thermal energy-storage material. In embodiments, upon releasing thermal energy to water to generate steam, the thermal energy storage medium is recycled for further use, such as to be reheated for further steam production.

[0049] In an aspect of the invention, a steel manufacturing process is provided. The steel manufacturing process comprises using renewable energy sources to reduce the emission of carbon- containing compounds. In an embodiment, the renewable energy sources are located in close proximity to the steel production vessels. In an embodiment, water is dissociated into H₂ and O2 by first pre-heating H₂0(1) to H₂0(g) (steam).

[0050] In an aspect of the invention, water is converted to steam using a thermal energy source prior to electrolysis. In embodiments, high temperature steam electrolysis with a portion of the requisite dissociation energy supplied from a thermal energy source is more efficient than low temperature water electrolysis.

[0051] In embodiments, water is dissociated to hydrogen (H₂) and oxygen (0₂). In various embodiments, water is dissociated via electrolysis. In an embodiment, the requisite power for the electrolysis of water is provided from one or more of renewable energy resources, off peak electricity sources and conventional power plants. In an embodiment, one or both of the H₂ and 0₂ generated from H 0 may be stored in suitable storage modules for later use.

[0052] In an embodiment, the H₂ and 0₂ generated from H₂0 are used to form steel. In an embodiment, the production of steel comprises reducing a material having metal ore or ore equivalents, including, but not limited to, iron ore, mill scale, nickel ore, or other ferrous metals chemically combined with oxidative elements, in suitable reduction modules using H₂ for chemical reduction potential and combusting the H₂ to provide heat for the reduction reaction.

[0053] In embodiments, systems and components used to form H₂ and 0₂ from H₂0, including one or more solar collectors, one or more heat exchangers (each having a thermal energy storage material), wind turbines and/or fuel cells, and electrolysis modules, are located at the same location. This advantageously minimizes dangers associated with the transport of hydrogen, in addition to the high costs associated with transporting hydrogen. Further, having all components at the same locations aids in maintenance and repair, and minimizes downtime, as the components may be readily accessed. [0054] In embodiments, renewable energy is used to heat an energy storage medium to release energy. The energy released from the energy storage medium is used to generate steam from water. Next, water is dissociated to form H₂ and 0₂. In an embodiment, water is dissociated through the electrolysis of water in an electrolysis module. The energy for the electrolysis of water may be provided from one or more renewable energy sources. In an embodiment, the electrolysis module is in close proximity to the one or more renewable energy sources. In embodiments, the energy for the electrolysis of water is provided from one or more of wind energy, solar energy, geothermal energy, wave energy, hydropower, electricity obtained from the combustion of biofuel, and electricity from a fuel cell. In a preferable embodiment, the energy for the electrolysis of water is provided from one or more of wind turbines and/or one or more fuel cells. Next, H₂ and/or 0₂ are used to form steel. In an embodiment, any water formed during the formation of steel may be recycled for further use. For example, water may be recycled to generate steam for further electrolysis.

[0055] In an embodiment, a method of producing hydrogen by the electrolysis of steam comprises converting solar radiation (or solar energy) into thermal energy and electrical energy, and using at least a portion of the thermal energy to convert water into steam and to heat the steam to a temperature of at least 700°C. In an embodiment, electrical energy is generated with the aid of photovoltaic (solar) cells. At least a portion of the electrical energy and at least a portion of the remaining thermal energy is used to operate an electrolysis cell (or module) to decompose steam into H₂ and 0₂. The thermal energy provides at least a portion of the endothermic energy required for the electrolysis of H₂0, which reduces the additional external electrical energy required for electrolysis. In an embodiment, the electrical energy from solar radiation (e.g., by way of photovoltaic cells) is augmented with electrical energy from one or more of other renewable energy sources, such as wind turbines, fuel cells, and a power grid.

[0056] In an embodiment, solar radiation is separated into a shorter wavelength component and a longer wavelength component. The shorter wavelength component is converted into electrical energy and the longer wavelength component is converted into thermal energy. In an embodiment, the longer wavelength component is used to melt a thermal energy storage material, such as MgF₂. Alternative methods for forming H₂ from H₂0 with the aid of solar radiation may be found in, for example, U.S. patent No. 5,658,448 to Lasich ("PRODUCTION OF HYDROGEN FROM SOLAR RADIATION AT HIGH EFFICIENCY"), which is entirely incorporated herein by reference.

[0057] With reference to FIG. 2, a method 100 for forming H₂ and 0₂ for use in steel production is provided, in accordance with an embodiment of the invention. In a first step 105, a renewable energy source is used to heat a heat-releasing energy storage medium (also "thermal energy storage material" herein). In an embodiment, the thermal energy storage material comprises MgF₂. In an embodiment, the renewable energy source is solar energy, which may be provided with the aid of a vertically stacked solar energy concentrator. In an embodiment, the thermal energy storage is heated at a temperature and period of time such that a predetermined fraction of the thermal energy storage material is melted. In an embodiment, the thermal energy storage material is heated to its melting or boiling point. Next, in step 110, heat from the heat-releasing energy storage medium is used to generate H₂0(g) (steam) from H₂0(1). In an embodiment, this is accomplished with the aid of a heat exchanger-type vessel having water tubes in thermal contact with the heat-releasing energy storage medium. Next, in step 115, H₂ and 0₂ are generated from steam. In an embodiment, H₂0 is dissociated into H₂ and 0₂ using electrolysis. In an embodiment, the energy required for the electrolysis of steam is provided from one or more renewable energy sources, such as one or more wind turbines. In another embodiment, the energy required for the electrolysis of steam is provided from a fuel cell, such as a solid oxide fuel cell ("SOFC"). In another embodiment, the energy required for the electrolysis of steam is provided from one or more wind turbines and one or more fuel cells. Next, in step 120, H₂ and/or 0 are used in a downstream process, such as steel production. Next, in step 125, any water formed produced in the downstream process may be recycled, such as to step 110.

[0058] With reference to FIG. 3, a system 200 for forming steel is shown, in accordance with an embodiment of the invention. First, MgF₂ is heated to slightly below its vaporization point until all or substantially all of the MgF₂ heat storage medium is melted. In embodiments, MgF₂ is heated using solar energy. In an embodiment, MgF₂ is heated using a solar energy concentrator 205, such as a vertically stacked solar energy concentrator. In an embodiment, MgF₂ is heated using a solar energy concentrator described in U.S. Provisional Patent Application No. 61/277,696, which is entirely incorporated herein by reference. The heat storage capacity of MgF₂ may be sized to pre-heat an appropriate or predetermined quantity of incoming raw cold water to a desired or predetermined temperature with the aid of a heating device 210, such as a heat exchanger. In an embodiment, cold water is heated to a temperature less than about 1263°C. The water is pre-heated to a temperature that is sufficient for continuous overall steel production needs, particularly for the formation of H₂ from a down stream high temperature steam electrolysis system (HTSS) or module 215.

[0059] In an embodiment, the HTSS 215 may dissociate H₂0 into H₂ and 0₂ via the following half- cell (redox) reactions:

(1) 2 H₂0(g) + 4 e 2 H₂ + 2 O²- (cathode)

(2) 2 0²→ 0₂ + 4 e (anode)

(3) 2 H₂0 ^ 2 H₂ + 0₂ (net)

[0060] In embodiments, the HTSS 215 may comprise an anode and cathode (see FIG. 4). In an embodiment, the cathode is a porous (or semi-permeable) cathode and the anode is a porous anode. The HTSS 215 may further comprise a gas-tight (or impermeable) electrolyte for providing a chemical potential gradient for separating hydrogen and oxygen ions. Upon the application of a potential drop (or electromotive force, "V") across the anode and the cathode, the separation of steam into H₂ and 0₂ is coupled with the flow of electros from the anode to the cathode.

[0061] With continued reference to FIG. 3, in an embodiment, the HTSS 215 comprises a gas tight ceramic electrolyte. In an embodiment, following the dissociation of water into H₂ and 0₂, H₂ and 0₂ may be separated. In an embodiment, if steam is thermally dissociated to H and 0₂ at 1800°C-2400°C, then a ceramic -based membrane may be used to separate H₂ and 0₂. The ceramic-based membrane may include a ceramic-ceramic composite material or a ceramic-metal composite material. In another embodiment, H₂ and 0₂ may be separated with the aid of a solid electrolyte (solid electrolyte oxygen separation). In an embodiment, if steam is thermally dissociated to H₂ and 0₂ at a temperature between about 1800^CC-2400°C, a boron-containing heat-releasing energy storage medium may be used, the energy storage medium having a melting point of about 2300°C and a boiling point of about 2550°C. In such a case, a container vessel comprising a tungsten and rhenium-containing alloy, such as W3/5%Re (melting point of 3350°C, boiling point of 3410°C) or W-25Re (melting point of 3120°C, boiling point of 3130°C), may be used. Some additional container materials may include Osmium Os (melting point 3,027 °C (3,300 K)); Rhenium Re (melting point 3, 180 °C (3,450 BQ); Tungsten W (melting point 3,422 °C (3,695 K)); Carbon (diamond) C (melting point 3,550 °C (3,820 K)); or Tungsten coated Carbon (graphite) C (melting point 3,675 °C (3,948 K))†.

[0062] In an embodiment, power, such as direct current (DC) power, from a wind energy tower 220, which may operate above the HTSS Solid oxide electrolytic cell on a continuous (i.e., 24 hours per day, 7 days per week, 52 weeks per year) basis, may be used to produce H₂ and 0₂, which may subsequently be used in one or more downstream processes. In an embodiment, ¾ and 0₂ formed from the electrolysis of steam are used to produce steel. In another embodiment, the energy required for the electrolysis of water may be provided from a fuel cell 225. In an embodiment, the fuel cell 225 is a solid oxide fuel cell (SOFC).

[0063] In embodiments, the fuel cell 225 may include an anode, a cathode and an electrolyte. The application of load or resistance ("R") from the anode to the cathode provides for the flow of electrons upon the dissociation of a fuel and concomitant flow of ions. The electrons may be used to

electrochemically dissociate H₂0 in the HTSS 215.

[0064] In embodiments, the anode and the cathode may be formed of a conductive, permeable (or semi -permeable) material. In embodiments, the anode and cathode comprise one or more transition metals selected from Cu, Ni, Pt, Au and Ag. In an embodiment, the anode is formed of Pt. In an embodiment, the cathode is formed of Ni.

[0065] In an embodiment, the fuel cell 225 is a hydrogen (or hydrogen-based) fuel cell. In an embodiment, the fuel cell 225 is as a proton exchange membrane (PEM) fuel cell (see FIG. 5). In another embodiment, the fuel cell 225 is a solid oxide fuel cell (see FIG. 6). In yet another embodiment, the fuel 225 is a molten carbonate fuel cell. In some embodiments, the fuel cell 225 comprises an electrolyte that is formed of a perovskite.

[0066] With reference to FIG. 5, a hydrogen-based PEM fuel cell is shown. The hydrogen fuel cell may include an electrolyte that is a proton exchange membrane ("PEM"), in which case the fuel call may be referred to as a PEM fuel cell (also "polymer electrolyte membrane fuel cell" herein). In an embodiment, at the anode of the PEM, hydrogen dissociates via H₂ -> 2 H⁺ + 2 e^" (E° = 0 V_SHE), and at the cathode, water is formed via 4 H⁺ + 4 e^" + 0₂ -> 2 H₂0 (E₀ = 1.229 V_SHE)- In various embodiments, the PEM may be formed of a platinum (or Pt-base catalyst) or an iron-based catalyst, such as an iron, nitrogen, and carbon-containing catalyst. In an embodiment, heat generated in the redox reaction is conveyed to H₂0, which exits the fuel cell. [0067] With reference to FIG. 6, an SOFC is shown. In an embodiment, the anode and cathode are formed of permeable materials to permit the flow of O2 and H₂ towards the electrolyte and the flow of H₂0 away from the electrolyte. The electrolyte is formed of an impermeable material. With reference to FIG. 6, in an embodiment, H₂ and CO are provided to the anode of the fuel cell as fuel and air is provided to the cathode of the fuel cell. The fuel cell provides a chemical potential gradient to form H₂0. At the anode, water is formed via 2 H₂ + O^2" -> 4 e^~ + 2 H₂0, and at the cathode, oxygen is dissociated via 0₂ + 4 e - -» 2 O²-. H₂0 and any unused fuel exit the fuel cell at an exit port. In an embodiment, H₂0 formed in the fuel cell 225 is directed to the HTSS 215 to form H₂ and 0₂. In an embodiment, heat generated in the redox reaction exits the fuel cell with air. In some cases, heat may exit the fuel cell with H₂0.

[0068] In an embodiment, the anode of the SOFC may formed of a ceramic material. The ceramic material may be porous to allow the fuel to flow towards the electrolyte. In embodiments, the cathode and anode are configured to conduct electrons to a load ( ) that is in electrical communication with a point of use, such as the HTSS 215. In an embodiment, the ceramic material of the anode includes cermet, which includes nickel mixed with the ceramic material that is used for the electrolyte in that particular cell, such as yttria-stabilized zirconia (YSZ). In an embodiment, the thickness of the anode is selected so as to enable the oxygen ions that diffuse through the electrolyte to oxidize hydrogen fuel.

[0069] In an embodiment, the electrolyte of the SOFC may be formed of a dense layer of ceramic that conducts oxygen ions. The conductivity of the electrolyte may be kept as low as possible to prevent electrical losses from leakage currents. In an embodiment, the electrolyte may be formed of YSZ, such as 8% form Y8SZ, or gadolinium doped ceria (GDC).

[0070] In an embodiment, the cathode is a thin porous layer on the electrolyte where oxygen reduction takes place. The cathode of the SOFC may be formed of lanthanum strontium magnetite (LSM) or a composite material having LSM and YSZ. In an embodiment, mixed ionic/electronic conducting (MIEC) ceramics, such as the perovskites (e.g., lanthanum strontium cobalt ferrite), may be used.

[0071] In an alternative embodiment, the fuel cell 225 is configured to operate using carbon- containing fuels. In some embodiments, the fuel cell 225 is a PEM fuel cell or SOFC configured to use a carbon-containing material, such as a hydrocarbon or alcohol, as fuel. For example, the fuel cell 225 may be a PEM fuel cell using methanol (CH₃OH) as fuel. In such a case, the fuel cell 225 may be referred to as a direct methanol fuel cell. The overall redox reaction for the direct methanol fuel cell is 2 CH₃OH + 3 0₂ 4 H₂0 + 2 C0₂. In another embodiment, the fuel cell may be configured to use ethanol as fuel. In some embodiments, the fuel cell 225 is configured to operate using a hydrocarbon, C_xH_y, wherein 'x' and 'y' are numbers greater than zero. In an embodiment, the fuel cell is configured to operate using one or more of alkanes (e.g., methane, ethane), alkenes (e.g., ethene) and alkynes (e.g., ethyne). In

embodiments, the carbon-containing fuel serves as the oxygen anion acceptor in the redox half-cell reactions in the fuel cell.

[0072] With continued reference to FIG. 3, in an embodiment of the invention, H₂ and 0₂ formed from the electrolysis of water using the HTSS may be used as follows: 1) H₂ and 0₂ are directed to an oxy- hydrogen flame generator 230 at an H₂:0₂ ratio between about 1 :1 and 5:1, that operates at a temperature less than about 2800°C; 2) H₂ is directed to an iron-producing blast furnace 235 to reduce iron in a two-step process (i.e. , Fe³⁺ -> Fe²⁺ -> Fe) that produces steam and sponge iron as by products with no C0₂ emission; 3) 0₂ is supplied to a multi-grade steel smelter 240 that forms a desired type of steel (having a predetermined composition) from Fe, Mg, B, Cr, Mo, carbon, while removing S, P, Si and other impurities as oxide effluents; and 4) scraps from the steel smelter 240 are treated with oxy-hydrogen in s scrap smelter 245. In an embodiment, sulfur, phosphorous and silicon removed as oxides, such as, e.g., SO_x (e.g., SO, S0₂) PO_x and SiO_x (e.g., Si0₂), wherein 'x' are numbers greater than zero.

[0073] In an embodiment, H₂ and 0₂ formed from the dissociation of steam may be combined to form a mixture having H₂ and 0₂ in a ratio of about 1 : 1 , or 1.5:1, or 2: 1 , or 2.5: 1 , or 3 : 1 , or 3.5: 1 , or 4:1, or 4.5:1, or 5: 1 , or 10: 1 , or 20:1. In some embodiments, the hydrogen-to-oxygen ratio may be between about 1 and 20, or between about 2 and 5. In an embodiment, the hydrogen-to- oxygen ratio is about 2, which is the stoichiometric ratio. In some embodiments, the hydrogen-to-oxygen ratio of the mixture may be adjusted to achieve a desirable ignition (or autoignition) temperature.

[0074] In an embodiment, the oxy-hydrogen flame generator 230 supplies both hydrogen and oxygen, at a ratio between about 1 :1 and 5: 1 , to a point of use ("POU") in safe, secure and independent concentric tubes. In an embodiment, the hydrogen is in a central tube terminating about 1 inch farther, or 2 inches farther, or 3 inches farther than an oxygen-carrying outer tube at all POUs distributed across all production systems. In an embodiment, hydrogen is remotely auto-lit first before opening the oxygen flow whenever and wherever high temperature is needed. Oxygen may be replaced with air, N₂ or another inert gas (e.g. , He, Ar), which may be added to maintain other temperatures less than about 2800°C in the blast furnace, scrap iron, steel making furnaces/smelters.

[0075] FIG. 7 illustrates a steel smelter (or vessel) 240, in accordance with an embodiment of the invention. Iron (Fe) from the blast furnace 235 is directed to the steel smelter (or smelting vessel) 240 for forming steel of a desired or predetermined composition. In the illustrated embodiment, the smelting vessel includes a furnace for heating iron during steel formation. In an embodiment, a mixture of H₂ and 0₂, such as, e.g., oxy-hydrogen, is directed to the furnace to generate heat via combustion. During the formation of steel, slag (e.g., a mixture of metal oxides) is removed from the vessel. Oxygen (0₂) is added to oxidize impurities (e.g., S, P, Si) in Fe. In addition, oxygen may aid in the formation of one or more oxide layers (e.g., a CrO_x layer) on the steel formed in the vessel. In an embodiment, hydrogen may be added to further aid in the reduction of iron.

[0076] With continued reference to FIG. 7, one or more alloying elements may be added to the smelting vessel to achieve steel having a predetermined composition. In embodiments, alloying elements are selected from carbon (C), magnesium (Mg), boron (B), chromium (Cr), molybdenum (Mo), manganese (Mn) and, vanadium (V) and tungsten (W). The alloying elements used during the formation of steel, in addition to the processing conditions (pressure, temperature), may be selected to achieve a steel composition having a predetermined composition and material properties, such as hardness, thermal conductivity, and electrical conductivity. [0077] With continued reference to FIG. 7, in an embodiment, if the iron entering the smelting vessel is sufficiently hot, the furnace may be precluded. In another embodiment, the furnace may be located adjacent the smelting vessel.

[0078] In an embodiment, steel is formed at a smelting temperature between about 800°C and 1600°C, or between about 1000°C and 1400°C. In an embodiment, steel is formed at a temperature less than or equal to about 1370°C. In some embodiments, because the oxidation rate (including bulk oxidation) of metals may increase with increasing temperature, steel smelting is conducted in a low (or limited) oxygen environment.

[0079] In an embodiment, during nighttime use, steam may be generated from a heat exchanger that operates with the aid of a non-solar based renewable energy source, such as wind energy, geothermal energy, or wave energy. In an embodiment, electricity from an electricity grid is used to generate steam at night, while solar energy is used to generate steam during the day. This may lead to lower electricity costs if the demand for electricity is highest during the day and lower at night. Alternatively, ¾ and (¾ may be formed at night using electricity from an electricity grid, and during the day the process described above in the context of FIG. 3 may be used to form !¾ and (¾.

[0080] In an embodiment, H₂ and O2 produced during the day may be stored for future use. In an embodiment, H2 and O2 may be formed during the daytime and stored in separate H2 and O2 storage tanks. Then, at a future time, H₂ and O2 may be used in the processes described above in the context of FIG. 3. Alternatively, ¾ and O2 may be used to generate electricity, which may be directed to a power grid or used in other processes. In an embodiment, H₂ and O2 formed from the dissociation of H₂0 may be used to generate electricity with the aid of a fuel cell, such as a polymer electrolyte membrane (PEM) fuel cell (see FIG. 4).

Parabolic solar dishes

[0081] In an aspect of the invention, parabolic (or paraboloidal) solar dishes are provided.

Paraboloidal solar dishes of embodiments of the invention may include parabolic reflective surfaces for directing sunlight to a storage unit housing a thermal energy storage medium (or material). In embodiments, the thermal energy storage medium may include one or more of calcium chloride, barium chloride, strontium chloride, sodium bromide, potassium bromide, magnesium bromide, sodium fluoride, potassium fluoride, magnesium fluoride, lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, strontium iodide. In an embodiment, the thermal energy storage medium may include one or both of magnesium fluoride (MgF₂) and boron.

[0082] In an embodiment, a solar dish includes a reflective surface for directing light to a focal point of the reflective surface; an energy storage vessel having an energy storage medium disposed at the focal point of the reflective surface; one or more ball bearings disposed at an underside of the reflective surface; and two or more motors for adjusting the reflective surface along two or more axes. The reflective surface may be a parabolic reflective surface. The energy storage vessel may include any material configured to retain solar energy, such as, for example, MgF₂ or boron. [0083] FIG. 8 illustrates a paraboloidal solar dish, in accordance with an embodiment of the invention. The paraboloidal solar dish includes concentrating solar reflectors that are pivoted on ball bearings disposed at measured (or predetermined) distances from the vertices of the dish and coupled to a dual axis, chain driven motorized sun tracker. A solar thermal energy storage tank having a solar thermal energy storage material, such as one or more salts, including MgF₂ and boron, is positioned at the focus point of the dish. The dish may include mechanical supports at various points along the dish. In an embodiment, the dish may include additional three columns of variable heights to secure the dish to the base structure or to drive a three-point tracking system a in push-and-pull manner.

[0084] With continued reference to FIG. 8, solar energy is concentrated by the dish at the focus (or focal) point of the dish. That is, rays of sun incident on the dish are directed to the focal point of the dish. The thermal energy storage tank, having a thermal energy storage material, is disposed at (or near) the focus of the dish. The dish is configured to focus solar energy on the solar thermal energy storage tank, which heats solar thermal energy material in the solar thermal energy storage tank.

[0085] The dish may include one or more motors for adjusting the dish. In the illustrated embodiment of FIG. 8, the dish includes a first motor for adjusting the dish along a first axis (parallel to the plane of the page) and a second motor for adjusting the dish along a second axis orthogonal to the first axis (perpendicular to the plane of the page). The first and second motor may be attached to the dish via one or more attachment members (e.g., belts, cables).

Methods and systems for generating hydrogen and oxygen for steel production

[0086] In another aspect of the invention, systems and methods for generating hydrogen (H₂) and oxygen (0₂) are provided. One or both of hydrogen and oxygen may be used to generate steel, or stored for used in generating power (or electricity), hydrocarbons or ammonia.

[0087] In some cases, liquid water may be heated to generate steam with the aid of a heat exchanger. Energy for heating liquid water to steam in the heat exchanger may be provided by a renewable energy source, such as a carbon- free renewable energy source. In some cases, energy for heating liquid water to steam may be provided by solar radiation, or exclusively by solar radiation. Steam may subsequently be dissociated into hydrogen (H₂) and oxygen (0₂) with the aid of a hydrogen generator. Hydrogen and oxygen may then be used for forming steel, as described above. In an embodiment, the energy required to generate steel may be provided exclusively from solar energy.

[0088] In some cases, the hydrogen generator may be a shell-and-tube hydrogen reactor (also "shell- and-tube reactor" herein). In other cases, the hydrogen generator may be a fluidized bed hydrogen reactor (also "fluidized bed reactor" herein) (see below). In other cases, the hydrogen generator may be a combination of shell-and-tube hydrogen reactors and fluidized bed hydrogen reactors.

[0089] In some cases, the hydrogen generator may include reactive surfaces having elemental iron. Steam may be directed over the elemental iron-containing (e.g., Fe) surfaces to generate iron oxide- containing (e.g., Fe₂0₃) surfaces and H₂. H₂may be removed from the hydrogen generator. N , air or other oxidatively inert (or non-oxidizing) gas may be directed in the hydrogen generator and brought in contact with the iron oxide-containing surfaces to generate (or regenerate) elemental iron-containing surfaces and 0₂. 0₂ may be removed from the hydrogen generator. In some cases, the hydrogen generator may be a shell-and-tube reactor. In other cases, the hydrogen generator may be a fluidized bed reactor.

[0090] In some implementations, the heat exchanger for generating steam may be disposed in proximity to the hydrogen generator, such as the shell-and-tube hydrogen reactor. Additionally, the hydrogen generator (e.g., shell-and-tube hydrogen reactor) may be disposed in proximity to the steel smelter. In some cases, the heat exchanger may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the hydrogen generator, and the hydrogen generator may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the steel smelter. For example, the heat exchanger may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the shell-and-tube hydrogen reactor.

[0091] In some cases, a renewable energy source (e.g., solar dish, parabolic solar dish, solar concentrator) for providing energy to the heat exchanger may be disposed in proximity to the heat exchanger. For instance, the renewable energy source (e.g., solar dish, parabolic solar dish, solar concentrator) may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the heat exchanger. The renewable energy source may be thermally coupled to (or in thermal communication with) the heat exchanger.

[0092] With reference to FIG. 9, a system for generating hydrogen and oxygen from water may include a paraboloidal (or parabolic) concentrating solar power (CSP) dome, a sun tracker, and a shell- and-tube hydrogen reactor. The sun tracker may be a vertical staggered dual axis sun tracker. The system may further include a hydrogen and oxygen separator downstream of the hydrogen reactor. The sun tracker may be configured to direct solar energy to the parabolic CSP dome. The parabolic CSP dome is configured to direct solar energy to a solar thermal energy storage tank (or vessel) having a thermal energy storage material.

[0093] In an embodiment, for the dome, x=4f(y²+z²), wherein 'x' is the x-coordinate of the dome measured from vertex of the parabolic dome, f=h/a², and 'h' is the maximum depth of the dome and 'a' is the diameter of the dome opening. The surface area of the dome is na((a²+4h²)3/2- a³)/3h², and the volume of the dome is (na²h/4). In an embodiment, the sun tracker may include motorized rotational control coupled with a vertical linear slider to track sun real time using N=a/4 units of 4' by 2y sized, light 95% solar reflectors in staggered fashion to avoid high altitude wind force. [0094] Shell-and-tube hydrogen reactors (also "shell-and-tube reactors" herein) may include tubes formed of an iron-containing material, such as iron, iron oxide, a core coated with iron oxide, or a core coated with iron. The cores of coated tubes may be formed of a material having a melting point above that of iron oxide. In some cases, the tubes may be formed of one or more of rubidium and tungsten. The shell of the shell-and-tube reactor may be formed of a material having a melting point above that of iron oxide. In some cases, the shell may be formed of one or more or rubidium and tungsten.

[0095] In some cases, a shell-and-tube reactor may include a plurality of tubes having fluid flow passages for coming in contact with steam. The tubes may be cylindrical, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, or octagonal. In other cases, the tubes may be formed of crossing or intersecting two-dimensional planes, such as shown in FIG. 14A, which shows intersecting planes forming reactive surfaces. Reactive surfaces 1401, 1402, 1403 and 1404 have been indicated in FIG. 14A. The surfaces of such tubes may be formed of, or coated with, an iron-containing material, such as iron or iron oxide. If iron is used, a first pulse of steam (or other oxidizing chemical) through the tubes may convert iron to iron oxide.

[0096] In other cases, a shell-and-tube reactor may include tubes having a tube-in-tube configuration, such as shown in FIG. 14B. Reactive tubes 1405, 1406, 1407 and 1408 have been indicated in FIG. 14B. That is, a tube may have one or more other tubes disposed in the tube, each of the tube and the one or more other tubes formed of, or coated with, an iron-containing material, such as iron or iron oxide. In cases in which iron is used, a first pulse of steam (or other oxidizing chemical) through the tubes may convert iron to iron oxide.

[0097] A tube-in-tube may have an outer tube and one or more inner tubes of decreasing radius with respect to the outer tube, each of the one or more inner tubes disposed in a larger tube. In such a configuration, a fluid passage may be provided between an outer surface of a tube and an inner surface of a next larger tube. Additionally, a fluid passage may be provided between an inner surface of the tube and an outer surface of a next smaller tube.

[0098] A shell-and-tube reactor may include tubes in a tube-in-tube configuration having 2 or more, or 3 or more, or 4 or more, or 5 or more, or 6 or more, or 7 or more, or 8 or more, or 10 or more, or 20 or more, or 30 or more, or 40 or more, or 50 or more, or 100 or more, or 1000 or more tubes of successively decreasing radii disposed within one another. For example, a tube-in-tube may include a first tube disposed in a second tube.

[0099] Tubes of a tube-in-tube configuration of tubes may have circular, elliptical, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, or octagonal cross-sections. Such tubes, along an axis orthogonal to a plane having the cross-sections, may be generally elongate, such as, for example, cylindrical or rectangular. This may maximize the contact area between a gas and one or more surfaces of the tubes.

[00100] In the hydrogen reactor, hydrogen and oxygen may be generated with the aid of steam generated via renewable energy (e.g., solar renewable energy) by first thermally dissociating Fe2C>3 to form Fe and oxygen. The dissociated Fe may then react with high pressure steam to generate hydrogen. This process may convert Fe to Fe₂0₃. That is:

(1) 2 Fe₂0₃→ 4 Fe + 3 0₂(g)

(2) 2 Fe + 3 H₂0→ Fe₂0₃ + 3H₂(g)

[00101] Reaction (1) may be operated at a temperature between about 300°C and 1600°C, or between about 400°C and 1600°C. Reaction (1) may be performed at about the melting point of Fe₂0₃ (1566°C). Reaction (2) may be performed at a temperature between about 100°C and 1000°C, or 125°C and 400°C, or between about 150°C and 350°C. For instance, reaction (2) may be performed at a temperature of about 200°C.

[00102] Reaction (1) may be endothermic and reaction (2) may be exothermic. Reaction (1) may have a reaction enthalpy of about 825.5 KJ/mol and reaction (2) may have a reaction enthalpy of about -100.07 KJ/mol.

[00103] With continued reference to FIG. 9, the paraboloidal dome directs solar energy to a thermal energy storage medium having one or more salts, such as MgF₂ or boron. The concentrated solar energy heats the thermal energy storage medium. Energy from the solar thermal energy storage medium (also "thermal energy storage medium" herein) is used to generate steam in a heat exchanger having the thermal energy storage medium (or material). In an embodiment, energy from the thermal energy storage medium is used to generate high temperature steam from liquid water or low temperature steam. Steam is directed to the shell-and-tube hydrogen reactor.

[00104] In the hydrogen reactor, in a first step, energy from steam is transferred to Fe₂0₃ to produce Fe and 0₂, per reaction (1) above. In a second step, Fe reacts with H₂0 to generate Fe₂0₃ and H₂, per reaction (2) above. Hydrogen and oxygen may be separated with the aid of a hydrogen and oxygen separator, which may be formed of palladium or other metal with a desirable lattice constant.

[00105] In an embodiment, H₂ and 0₂ are generated in one or more tubes disposed in the hydrogen reactor. The one or more tubes may have a honeycomb configuration. In an embodiment, steam generated with the aid of energy from the thermal energy storage medium enters the shell-and-tube hydrogen reactor on a shell side of the hydrogen reactor. Thermal energy is transferred to Fe₂0₃ to generate iron and oxygen on a tube side of the hydrogen reactor. In an embodiment, water or steam on the shell side of the hydrogen reactor then leaves the hydrogen reactor and is directed to the thermal energy storage medium to generate steam. Next, water (e.g., liquid water, steam) is provided to the tube side of the hydrogen reactor to generate Fe₂03 and hydrogen, per reaction (2) above.

[00106] In some situations, steam may enter the shell side of the hydrogen reactor at a temperature of about 400°C and a pressure of about 15 psig. Steam may enter the shell side of the hydrogen reactor at a temperature between about 300°C and 1300°C, or between about 400°C and about 1250°C, and a pressure greater than or equal to about 5 psig, or greater than or equal to about 10 psig, or greater than or equal to about 15 psig. On the tube side steam enters the hydrogen reactor at a temperature between about 100°C and 400°C, or between about 150°C and 350°C. Steam may be provided in a sensor-controlled closed loop environment. The sensor (or computer system coupled to the sensor) may be configured to detect when the partial pressure (or concentration) of oxygen is at a certain predetermined concentration (e.g., partial pressure). In some cases, following reaction (1), when the partial pressure of oxygen is below a certain level, the computer system may be configured to introduce steam into the tube side of the hydrogen reactor to generate Fe₂0₃ and H₂, per reaction (2).

[00107] The system of FIG. 9 may include one or more pumps to facilitate the flow of one or both of hydrogen and oxygen. In the illustrated embodiment of FIG. 9, the system may include a pump downstream from the hydrogen reactor and upstream from the hydrogen and oxygen separator. The pump may include one or more of a turbo molecular ("turbo") pump, cryogenic pump, ion pump, diffusion pump and mechanical pump. In an embodiment, the pump is configured to maintain a pressure at a downstream portion of the hydrogen reactor of less than or equal to about 10^"4 torr, or less than or equal to about 10^"5 torr, or less than or equal to about 10^"6 torr, or less than or equal to about 10^~7 torr, or less than or equal to about 10^"8 torr, or less than or equal to about 10^"9 torr.

[00108] The tubes of the hydrogen reactor may be formed of any metal or combination of metals, such as a metal alloy, having a melting point higher than the melting point of Fe2C>3. In an embodiment, the tube may be formed of one or more of rubidium and tungsten.

[00109] In some implementations, the tubes may be coated with FeO_x, wherein 'x' is a number greater than zero. In some cases, FeOx may be Fe₂C>3. Upon heating, Fe₂C>3 may be converted to Fe and O2. Fe may cover reactive surface of the tubes. Bringing steam in contact with the Fe-coated tubes may convert Fe to Fe₂0₃ and simultaneously generating H₂.

[00110] In some situations, the hydrogen and oxygen generated by the hydrogen reactor may be provided for steel production (see above). Alternatively, one or both of hydrogen and oxygen generated by the shell-and-tube hydrogen reactor may be used to generate ammonia (NH₃), stored for subsequent production of electricity with the aid of a fuel cell, used to generate power, or used to generate hydrocarbons (see below).

[00111] With reference to FIG. 10, in an alternative embodiment, the paraboloidal dome and sun tracker of FIG. 9 may be replaced (or used in conjunction with) a paraboloidal (or parabolic) CSP dish, such as the dish of FIG. 8.

[00112] With reference to FIG 11, in an alternative embodiment, the shell-and-tube hydrogen reactor of FIGs. 9 and 10 may be replaced with an electrolyzer for generating H₂ and 0₂ from steam. In an embodiment, high temperature steam is generated from heat provided by a thermal energy storage medium. Next, steam may be directed to the electrolyzer for generating H₂ and 0₂ via the electrolysis (i.e., dissociation) of H₂0. H₂ and 0₂ formed via the electrolyzer may be used for steel production.

[00113] With reference to FIGs. 9-11, hydrogen and oxygen formed from steam may be directed to a steel smelter downstream from the shell-and-tube hydrogen reactor or electrolyzer. The steel smelter may be used to form steel with the aid of hydrogen and oxygen generated in the hydrogen reactor or electrolyzer, as described above. [00114] The systems and methods of FIGs. 9-11 may be used with any systems and methods provided herein. For example, the systems of FIGs. 9 and 10 may be used for generating hydrogen and oxygen for the steel production systems of FIGs. 1 and 3.

[00115] In some embodiments, the hydrogen generator of FIG. 1A may be a fluidized bed reactor. For example, the hydrogen reactor of FIGs. 9 and 10 may be replaced by a fluidized bed reactor. That is, a fluidized bed reactor may be used in place of the shell-and-tube hydrogen reactors of FIG. 9 and 10. The fluidized bed reactor may be used to generate H₂ and 0₂, which may be used, for example, in steel production. Alternatively, a system for generating hydrogen and oxygen may include a shell-and-tube hydrogen reactor and fluidized bed reactor.

[00116] For instance, a system for forming hydrogen and oxygen may include a heat exchanger having a thermal energy storage medium, the heat exchanger for generating steam from water. Energy for heating liquid water to steam may be provided by a renewable energy source, such as a carbon- free renewable energy source. In some cases, energy for heating liquid water to steam may be provided by solar radiation, or exclusively by solar radiation. The system may further include a fluidized bed reactor downstream from the heat exchanger, the fluidized bed reactor for generating hydrogen and oxygen. The fluidized bed reactor may include particles formed of or coated with an iron- containing material, such as elemental iron or iron oxide. Alternatively, the fluidized bed reactor may include nanoparticles or microparticles formed of or coated with an iron- containing material, such as elemental iron or iron oxide iron oxide-coated nanoparticles. The system may further include a steel smelter downstream from the fluidized bed reactor, the steel smelter for forming steel using heat produced through the combustion of at least a portion of the hydrogen and oxygen generated in the fluidized bed reactor.

[00117] In some implementations, the heat exchanger for generating steam may be disposed in proximity to the fluidized bed reactor. Additionally, the fluidized bed reactor may be disposed in proximity to the steel smelter. In some cases, the heat exchanger may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the fluidized bed reactor, and the fluidized bed reactor may be situated at most about 1 foot, or 2 feet, or 3 feet, or 4 feet, or 5 feet, 10 feet, or 20 feet, or 30 feet, or 40 feet, or 50 feet, or 60 feet, or 70 feet, or 80 feet, or 90 feet, or 100 feet, or 200 feet, or 300 feet, or 400 feet, or 500 feet, or 1000 feet, or 2000 feet, or 5000 feet, or 10,000 feet from the steel smelter.

[00118] A method for forming hydrogen and oxygen may include generating steam upon the application of energy from a thermal energy storage material to liquid water, the thermal energy storage material heated with the aid of a carbon- free renewable energy source, such as solar radiation. The method may further include bringing N₂, air or any other gas or vapor having suitable thermodynamic properties (e.g., heat capacity) in contact with iron oxide-coated particles in a fluidized bed reactor to form iron-coated particles and oxygen (0₂). N₂, air or other gas (e.g., H₂0(g)) may have energy that is sufficient to effect the evolution of 0₂ from the iron oxide-coated particles. In some instances, such gas may have an energy that is greater than or equal to the energy of desorption of oxygen from an iron oxide surface. In other gases, such gas may have an energy that is greater than or equal to the energy of dissociation of iron oxide to iron and 0₂, and subsequent desorption of 0₂ from the iron oxide surface.

[00119] Next, steam may be brought in contact with the iron-coated particles in the fluidized bed reactor to form iron oxide-coated particles and hydrogen (H₂). In one embodiment, at least a portion of the H₂ and 0₂ may be converted to oxy-hydrogen. In another embodiment, steel may be formed in a steel smelter using iron from a hydrogen-based blast furnace, wherein heat to the steel smelter is provided via the combustion of at least a portion of the H₂ and 0₂ formed in the fluidized bed reactor. The process for generating H₂ and 0₂ in the fluidized bed reactor may be as set forth in reactions (1) and (2) above.

[00120] Alternatively, if iron or iron-coated particles (e.g., nanoparticles, microparticles) are used in an FBR, then the iron or iron-coated particles may first be contacted with H₂0 to generate iron oxide (e.g., Fe₂0₃) coated particles and H₂, which may be removed from the FBR. Next, the iron oxide-coated particles may be contacted with N₂, air or other gas with energy that may be sufficient to effect the dissociation of iron oxide to iron an 0₂, and subsequent desorption of 0₂ from the iron oxide surface. 0₂ may then be removed from the FBR.

[00121] H₂ and 0₂ formed in an FBR may be directed to a steel production system (such as system 040 of FIG. 1A) to form steel. Alternatively, H₂ and/or 0₂ may be stored in storage vessels for later use. In some situations, H₂ and 0₂ from an FBR may be directed to a gas separator for separating H₂ and 0₂.

[00122] In some instances, a fluidized bed reactor may include particles coated with an iron- containing material, such as iron oxide-coated particles, iron oxide-coated nanoparticles, iron oxide- coated mesoscopic particles, or iron oxide-coated particles having an iron oxide thin film on a core formed of a high temperature material. The high temperature material may have a melting point greater than a melting point of iron oxide. In some cases, the fluidized bed reactor may include iron oxide-coated particles having an iron oxide thin film on a core formed of one or more materials selected from TiO_x (e.g., Ti0₂), ZrO_x (e.g., Zr0₂), Al_xO_y (e.g., A1₂0₃) and SiO_x (e.g., Si0₂), wherein 'x' and 'y' are numbers greater than zero. The fluidized bed reactor may include iron oxide particles, nanoparticles or microparticles without a core. Iron oxide may be selected from Fe_xO_y, wherein 'x' and 'y' are numbers greater than zero. For example iron oxide, including iron oxide thin films, may include Fe₂C>3.

[00123] In some situations, a fluidized bed reactor may include iron-coated particles having a iron thin film on a core formed of one or more materials selected from TiO_x (e.g., Ti0₂), ZrO_x (e.g., Zr0₂), Al_xO_y (e.g., A1₂0₃) and SiO_x (e.g., Si0 ), wherein 'x' and 'y' are numbers greater than zero. Alternatively, the fluidized bed reactor may include iron particles, nanoparticles or microparticles without a core. In such cases, at least a portion of iron may be oxidized to iron oxide with the aid of steam from the heat exchanger (see above).

[00124] Fluidized bed reactors may include iron oxide-coated particles separated by particles having one or more materials with melting points greater than the melting point of iron oxide. In some situations, fluidized bed reactors may include iron-coated particles. Particles for use in fluidized bed reactors may be company-supplied particles, such as, e.g., particles supplied by Analogies In Matters of Science, Inc., Cold Spring, NY. Particles may be shaped to have increased surface areas, which may help optimize the kinetic rates of reaction and heat transfer to and from the particles. The particles may have regular and irregular shapes, such as spherical, cylindrical, square or rectangular.

[00125] The FBR may include iron-coated particles separated by spacer particles formed of material selected from TiO_x (e.g., Ti0₂), ZrO_x (e.g., Zr0₂), Al_xO_y (e.g., A1₂0₃) and SiO_x (e.g., Si0₂) ("the oxide particles"), wherein 'x' and 'y' are numbers greater than zero. In one embodiment, the ratio between the iron-coated particles and the spacer particles may be 1 : 1 , or 1 :2, or 1 :3, or 1 :4, or 1 :5, or 1 :6, or 1 :7, or 1 :8, or 1 :9, or 1 :10, or 1 :15, or 1 :20. In another embodiment, the fraction of particles in the FBR that are spacer particles may be at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 35%, or at least 40%, or at least 45%, or at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%.

[00126] In one embodiment, a fluidized bed reactor having iron oxide-coated particles may be used in place of, or in conjunction with, any of the systems provided herein, such as the shell-and-tube hydrogen reactors of FIGs. 9 and 10. In another embodiment, a plurality of fluidized bed reactors may be used in series (i.e., one after another) or parallel.

[00127] With reference to FIG. 12, a system is shown for generating hydrogen (H₂) and oxygen (0₂), in accordance with an embodiment of the invention. First, high temperature nitrogen (N₂), air or any other gas or vapor having a desirable heat capacity is directed through a fluidized bed reactor ("FBR") having iron oxide coated particles to reduce iron oxide to iron and oxygen. The iron oxide-coated particles may be converted to iron-coated particles. Oxygen is removed from the system with the aid of a pump (not shown, see FIG. 13) fluidically upstream ("upstream") from the FBR. Next, high temperature water or steam (H₂0(g)) is directed through the FBR to generate H₂ and iron oxide on iron-coated particles.

Hydrogen is removed from the FBR with the aid of the pump. High temperature steam may be formed by heating liquid water (H₂0(1)) with the aid of an energy source, which may be any solar energy source provided herein. The energy source may include a heat exchanger for bringing a thermal energy storage medium (or material) in thermal contact with water to generate stream. For example, the energy source may be the pivoted horizontal paraboloidal solar dish and associated components of FIG. 8, or the paraboidal CSP dome and sun tracker and associated components of FIG. 9, or the paraboidal CSP dish and associated components of FIG. 10. In one embodiment, a thermal energy storage material (e.g., MgF₂) may be heated, such as, e.g., to its melting point, with the aid of solar energy from a solar energy concentrator (e.g., vertically stacked solar energy concentrator). The thermal energy storage material may be brought in thermal contact with H₂0(1) to generate H₂0(g).

[00128] In one embodiment, the system of FIG. 12 may further include a steel smelter downstream from the fluidized bed reactor for forming steel. In another embodiment, the system of FIG. 12 may further include one or more metal generation unit operations downstream from the fluidized bed reactor, the one or more metal generation unit operations for generating one or more metals.

[00129] With reference to FIG. 13, a fluidized bed reactor ("FBR") is illustrated having Fe₂0₃ nanoparticles or an Fe₂C>3 atomic layer deposited on Zr0₂ nanoparticles, in accordance with an embodiment of the invention. In one embodiment, the fluidized bed reactor may be the FBR of FIG. 12. In one embodiment, AI2O3 nanoparticles may be provided in addition to the Fe2C>3 coated nanoparticles to separate Fe203-coated nanoparticles from one another. This may advantageously prevent agglomeration of Fe2C>3-coated nanoparticles.

[00130] With continued reference to FIG. 13, the FBR may be a high temperature ceramic fluidized bed reactor which is fitted with porous distributor at bottom and an H₂ or <¾ gas filter above a particle or nanoparticle bed of the FBR. The FBR may include a mesh and/ or distributor for distributing the flow of gas throughout the FBR and for preventing particles from leaving the FBR. In addition, the FBR may include a vibrating member for vibrating the particles in the FBR to prevent agglomeration of the particles. The vibrating member may be disposed above or below a distributor of the FBR.

[00131] With continued reference to FIG. 13, hot air or N₂ at a temperature less than about 1600°C, or less than about 1500°C, which may be carrying heat from solar thermal storage tank, is passed through the bottom distributor plate at optimum velocity to ensure that all or a substantial portion of Fe₂03 begin melting, leading to the release of oxygen from the Fe₂C>3. Upon melting, Fe₂C>3 forms Fe. In cases in which iron oxide-coated (e.g., Fe₂C>3-coated) nanoparticles are used, a layer of Fe is formed on the support material. Next, water may be introduced into the FBR. In one embodiment, high temperature water or steam (e.g., boiled deonized water) may be introduced into the FBR. Water may react with Fe to form Fe₂03 and ¾. ¾ formed upon reaction between H₂0 and Fe may be directed from the FBR to an H₂/0₂ separator and subsequently to an H₂ storage tank (or "storage vessel"). In one embodiment, H₂0 may be introduced into the FBR from a bottom or top portion of the FBR.

[00132] With continued reference to FIG. 13, a system having the FBR may include one or more pumps for directing gases out of the FBR, pressure sensors ("PI" and "P2", as illustrated) for measuring a pressure of gases entering and leaving the FBR, and a mass spectrometer for measuring the composition of gases leaving the FBR. For the illustrated system, N2 (or air) and steam are provided to the FBR from a bottom portion of the FBR (on the sideof the FBR having pressure sensor PI), and H₂ and 0₂, including other effluent gases, are removed from the FBR from a top portion of the FBR (on the side of the FBR having pressure sensor P2).

[00133] In one embodiment, the system of FIG. 13 may further include a steel smelter downstream from the fluidized bed reactor for forming steel. In another embodiment, the system of FIG. 13 may further include one or more metal generation unit operations downstream from the fluidized bed reactor, the one or more metal generation unit operations for generating one or more metals.

[00134] In embodiments, one or more process parameters may be selected so as to improve or optimize (e.g., maximize) the output of hydrogen (H₂) and oxygen (O₂). For example, one or more process parameters may be varied to achieve an improved (or optimum) output of hydrogen and oxygen. In one embodiment, process parameters may be selected so as to optimize (or improve) H₂ and 0₂ readings in the mass spectrometer or any other device configured to detect H₂ and <¾. In another embodiment, flow rates may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen. In another embodiment, the temperature of water (or steam) may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen. In another embodiment, the size (e.g., diameter and/or length) of the FBR may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen. In another embodiment, the temperature of N₂, air or any other gas for reducing iron oxide may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen. In another embodiment, the size of particles (e.g., iron oxide-coated particles and/or spacer particles) may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen. In other embodiments, one or more of materials, flow rates, pressures, temperatures, residence times and space velocities may be selected so as to optimize H₂ and 0₂ detected in the mass spectrometer or any other device configured to detect hydrogen and oxygen.

[00135] In some situations, a system for generating hydrogen and oxygen from steam may include a plurality of hydrogen reactors or fluidized bed reactors in parallel. This may provided for forming H₂ and 0₂ simultaneously or nearly simultaneously. In some cases, this may preclude the need of H₂ and/or 0₂ storage vessels. H₂ and 0₂ may be used, for example, to generate steel, as described above. For example, a system may include a first fluidized bed reactor and second fluidized bed reactor in parallel, the first FBR having iron coated particles and the second FBR having iron oxide coated particles. Directing (or in some cases pulsing) steam into the first and second FBRs may generate H₂ in the first FBR and 0₂ in the second FBR, thereby forming iron oxide-coated particles in the first FBR and iron coated particles in the second FBR. Next, directing steam into the first and second FBRs may generate 0₂ in the first FBR and H₂ in the second FBR, thereby forming iron coated particles in the first FBR and iron oxide-coated particles in the second FBR. Alternatively, one or both of the first and second FBRs may be replaced with shell-and-tube hydrogen reactors, such as the shell-and-tube hydrogen reactors of FIGs. 9 and 10.

[00136] In some cases, the hydrogen generator may be maintained under vacuum to facilitate generation of H₂ and 0₂. For instance, a shell-and-tube reactor or fluidized bed reactor may be pumped with the aid of a pumping system to maintain a vacuum for forming H₂ and 0₂.

[00137] The hydrogen generator may be heated to provide desirable reaction rates and rates of desorption of H₂ and 0₂. Heating may be accomplished with the aid of inert gases (convective heating), resistive heating, or radiative heating.

[00138] Iron oxide (e.g., Fe₂0₃) for use in shell-and-tube hydrogen generators and fluidized bed reactors may be formed by depositing iron oxide on a support material, such as, e.g., titania and/or alumina. In some cases, iron oxide may be formed by atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD) and molecular beam epitaxy (MBE), including plasma-based ALD, CVD and PVD.

[00139] For instance, a layer of Fe₂C>3 may be formed by atomic layer deposition (ALD) using alternating and sequential pulses of ferrocene and an oxidizing agent, such as ozone (0₃) or oxygen (0₂). Fe₂0₃ may be formed at 200°C; the self-limiting growth of Fe₂0₃ may be observed at rates up to about 1-3 A/cycle, or 1-2 A/cycle. In some cases, a growth rate of about 1.4 A/cycle may be observed. Dense and robust thin films may be grown on various substrates, such as silicon-containing substrates, titania or alumina. Ferrocene may be used to uniformly coat a high surface area template with aspect ratio of at least about 1 :1, or 10:1, or 20:1, or 30:1, or 40:1, or 50:1, or 60:1, or 70:1, or 80:1, or 90:1, or 100:1, or 150:1.

[00140] Methods and systems provided herein may be used in other applications, such as, for example, energy storage, power generation, ammonia production, desalination, water purification. For example, methods for generating a hydrogen and oxygen using renewable energy sources, as described above, may be used to generate hydrogen and oxygen for use in a fuel cell which may be used to provide electricity during on-peak operating conditions.

[00141] As another example, hydrogen produced as described above may be used to generate hydrocarbons in a Fischer-Tropsch type synthesis, per the formula (2n+l) H₂ + n CO -> C„H_(2n+2) + n H₂0, wherein 'n' is a number greater than zero. H₂ formed according to the methods aove may be combined with CO to form a hydrocarbon (C_nH_2n+2), such as one or more of methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane and decane. Hydrocarbons may be oxidized to alcohols, ketones, aldehydes and carboxylic acids.

[00142] As another example, hydrogen produced as described above may be used to generate ammonia upon reaction with N₂, according to the formula 3 H₂ + N₂ -> 2 N¾. N₂ may be provided by air and purified to remove any oxygen prior to forming N¾. Such reaction may be facilitated with the aid of one or more catalysts, such as heterogeneous catalysts.

[00143] Methods and systems provided herein may be combined with, or modified by, other systems and methods, such as, for example, methods and/or systems described in U.S. Patent Publication No. 2009/0249922 to Soyland ("PROCESS FOR THE PRODUCTION OF STEEL USING A LOCALLY PRODUCED HYDROGEN AS THE REDUCING AGENT") and U.S. Patent No. 5,454,853 to Edelson ("METHOD FOR THE PRODUCTION OF STEEL"), which are entirely incorporated herein by reference.

Example 1

[00144] MgF₂ was heated to its melting point using solar energy from a vertically stacked solar energy concentrator. The solar irradiance from the solar energy concentrator was between about 1 and 6.3 KW/m₂. The MgF₂ was stored in a container having W-25Re or a ceramic material. The MgF₂ had a heat of fusion of about 0.94X10⁶J/kg at 1263°C (the melting point of MgF₂). The MgF₂ had a density of about 2430 Kg/m₃.

[00145] Next, heat released from the MgF₂ was used to generate steam from liquid water. Steam was then directed to an HTSS (see above) to dissociate H₂0 into H₂ and 0₂ via electrolysis. The energy required for the electrolysis of steam was provided from energy stored from a wind turbine and a solid oxide fuel cell (SOFC). The wind turbine and the SOFC were located locally in the vicinity of the electrolysis cell to minimize transmission losses and as backup.

[00146] Next, H₂ and 0₂ were separated. A portion of the H₂ was directed to a hydrogen-based blast furnace. Another portion of the H₂ was directed to an oxy-hydrogen flame generator. A portion of the 0₂ was directed to the oxy-hydrogen flame generator. Another portion of the 0₂ was directed to an oxy- hydrogen steel smelter. The oxy-hydrogen flame generator was used to generate a mixture of H₂ and 0₂ at a H₂:C>2 molar ratio between about 4 and 5. The oxy-hydrogen flame generator was operated at a maximum temperature of about 2800°C. Inert gases, such as N₂, were added to achieve a desired lower temperature.

[00147] In the hydrogen-based blast furnace, iron oxide, Fe³⁺, was reduced in a two-step process. First, Fe³⁺ was reduced to Fe²⁺: 3 Fe₂0₃ + ¾ 2 Fe₃0₄ + H₂0 (Ea = 89.13 kJ/mol, T_^ = 325.4°C). Next, Fe²⁺ was reduced to Fe: Fe₃0₄ + 4 H₂ 3 Fe + 4 H₂0 (Ea = 70.41 kJ/mol, T_max = 459.1°C).

[00148] In the oxy-hydrogen steel smelter, steel was formed from Fe and a predetermined amount of C, Mg, B, Cr, Mo, V, Mn and W, to form a predetermined composition (or type) of steel. During steel formation, S, P, Si and other impurities were removed as oxides with the aid of 0₂. The requisite heat for the production of steel was provided by combusting oxy-hydrogen. Recyclable scrap iron was directed to an oxy-hydrogen scrap smelter for treatment. Heat for the scrap smelter was provided by combusting oxy-hydrogen.

Example 2

[00149] A system for generating hydrogen and oxygen, such as the system of FIG. 9, was provided. The system may operate 330 days/yr using greater than or equal to about 2 or 3 hours per day of sun. The system may include a paraboloidal dome having a height of about 150 ft and a base of about 300 ft, in addition to a 150 ft by 300 ft aluminium reflector (e.g., Alanod aluminum reflector) of 95% reflectivity to generate, which may generate about 6152 kwh solar heat to thermally dissociate 4309 Kg/hr of Fe₂0₃ into Fe and 0₂ at a temperature between about 400°C and 1365°C. The shell-and-tube hydrogen reactor may include about 4309 Kg of Fe₂0₃ inside the tube bundle of particle size 20-40nm, 1.2gm cm3 porous bulk density, generating 161.62Kg/Hr of hydrogen and 1292.93 Kg/hr of 0₂ using 872 Kg/hr of high pressure process steam at a temperature greater than or equal to about 200°C. Steam at a temperature of about 1263°C from the solar heat exchanger may be used on the shell side. The system may include auxiliary equipment, such as solar thermal storage @5500XSUN, POU heat exchangers, hydrogen filters

(palladium or ceramic), CSD facility. Such equipment may use the above sizing limits. The production of 38 KWH/Kg of H₂ may use direct solar heat for this process.

[00150] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications may be made thereto and are contemplated herein. It is also not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the preferable embodiments herein are not meant to be construed in a limiting sense. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. Various modifications in form and detail of the embodiments of the invention will be apparent to a person skilled in the art. It is therefore contemplated that the invention shall also cover any such modifications, variations and equivalents.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A system for generating steel, comprising:

a heat exchanger for generating steam from liquid water with the aid of energy provided by a carbon- free renewable energy source;

a hydrogen generator downstream from the heat exchanger, the hydrogen generator for generating hydrogen (H₂) and oxygen (O2) from steam; and

a steel smelter downstream from the hydrogen reactor, the steel smelter for generating steel with the aid of H₂ and 0₂ formed in the hydrogen generator.

2. The system of Claim 1, wherein the hydrogen generator comprises a shell-and-tube hydrogen reactor.

3. The system of Claim 1, wherein the shell-and-tube hydrogen reactor tubes formed of or coated with iron oxide.

4. The system of Claim 1, wherein the hydrogen generator comprises a fluidized bed reactor.

5. The system of Claim 4, wherein the fluidized bed reactor comprises particles formed of or coated with iron oxide.

6. The system of Claim 1, further comprising an oxy-hydrogen generator downstream from the hydrogen generator.

7. The system of Claim 1, further comprising a hydrogen-based blast furnace downstream from the hydrogen generator and upstream from the steel smelter, the hydrogen-based blast furnace for generating iron (Fe) from Fe₂C>3.

8. The system of Claim 7, wherein the steel smelter is for generating steel using iron from the hydrogen-based blast furnace.

9. The system of Claim 1, wherein the heat exchanger comprises a heat-releasing energy storage medium.

10. The system of Claim 9, wherein the heat-releasing energy storage medium comprises one or more salts.

11. The system of Claim 10, wherein the one or more salts are selected from calcium chloride, barium chloride, strontium chloride, sodium bromide, potassium bromide, magnesium bromide, sodium fluoride, potassium fluoride, magnesium fluoride, lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, strontium iodide, and combinations thereof

12. The system of Claim 1, wherein the renewable energy source comprises a solar energy concentrator.

13. The system of Claim 12, wherein the solar energy concentrator is a vertically stacked solar energy concentrator.

14. The system of Claim 13, wherein the solar energy concentrator is adjacent the heat exchanger.

15. The system of Claim 1, wherein the renewable energy source is disposed at most about 500 feet from the heat exchanger.

16. The system of Claim 1, wherein the heat exchanger is disposed at most about 500 feet from the hydrogen generator.

17. The system of Claim 1, wherein the hydrogen generator is disposed at most about 500 feet from the steel smelter.

18. The system of Claim 1, wherein the renewable energy source comprises a solar dish, comprising:

a reflective surface for directing light to a focal point of the reflective surface;

an energy storage vessel having an energy storage medium disposed at the focal point of the

reflective surface;

one or more ball bearings disposed at an underside of the reflective surface; and two or more motors for adjusting the reflective surface along two or more axes.

19. The system of Claim 1, wherein the solar dish is a parabolic solar dish.

20. The system of Claim 1, wherein the hydrogen generator comprises an electrolysis unit.

21. The system of Claim 1, wherein at least a portion of the energy for generating H₂ and 0₂ from steam is provided by one or more of the renewable energy source and a fuel cell.

22. The system of Claim 21 , wherein the fuel cell is a solid oxide fuel cell.

23. The system of Claim 1, wherein the renewable energy source is selected from the group consisting of a photovoltaic cell, geothermal energy generator, wind turbine, wave energy generator and hydroelectric energy generator.

24. A method for forming steel, comprising:

generating steam from liquid water with the aid of energy provided by a renewable energy source;

generating hydrogen (H₂) and oxygen (0₂) from steam; and

forming steel in a steel smelter using iron from a hydrogen-based blast furnace, wherein steel is generated with the aid of the H₂ and 0₂ generated from steam.

25. The method of Claim 24, wherein dissociating steam into H₂ and 0₂ comprises:

contacting an elemental iron-containing material with steam to form an iron oxide- containing material and H₂; and

dissociating the iron oxide-containing material into an elemental iron-containing material and 0₂.

26. The method of Claim 25, wherein the iron oxide-containing material is dissociated with the aid of N₂ or air.

27. The method of Claim 24, further comprising generating oxy-hydrogen from H₂ and 0₂.

28. The method of Claim 27, wherein forming steel comprises using energy from combusting at least a portion of the oxy-hydrogen.

29. The method of Claim 24, wherein H₂ and 0₂ are generated from steam in a shell-and-tube reactor or a fluidized bed reactor.

30. The method of Claim 24, wherein generating steam from liquid water comprises:

directing energy from the renewable energy source to a thermal energy storage medium; and

generating steam with the aid of renewable energy stored in the thermal energy storage medium.

31. A method for forming hydrogen and oxygen, comprising:

bringing N₂ or air in contact with iron oxide-containing surfaces in a hydrogen generator to form iron-containing surfaces and oxygen (0₂);

removing 0₂ from the hydrogen generator;

bringing steam in contact with the iron-containing surfaces in hydrogen generator to form iron oxide-containing surfaces and hydrogen (H₂), wherein the steam is generated with the aid of energy from a carbon- free renewable energy source; and

removing H₂ from the hydrogen generator.

32. The method of Claim 31, wherein the hydrogen generator is a shell-and-tube reactor or a fluidized bed reactor.

33. The method of Claim 31, wherein the H₂ and 0₂ are formed for use in steel smelting.

34. The method of Claim 33, further comprising forming steel in a steel smelter with the aid of H₂ and 0₂ formed in the hydrogen generator.

35. The method of Claim 34, wherein steel is formed using iron from a hydrogen-based blast furnace, wherein heat to the steel smelter is provided via the combustion of at least a portion of the H₂ and 0₂ formed in the hydrogen generator.

36. A system for forming steel, comprising:

a heat exchanger having a heat-releasing energy storage medium, the heat exchanger for generating steam from water; an electrolysis unit downstream from the heat exchanger, the electrolysis unit for generating ¾ and O2 from steam;

an oxy-hydrogen generator downstream from the electrolysis unit;

a hydrogen-based blast furnace downstream from the electrolysis unit, the hydrogen- based blast furnace for generating iron (Fe) from Fe2C>3; and

a steel smelter downstream from the electrolysis unit, the steel smelter for generating steel using iron from the hydrogen-based blast furnace.

37. The system of Claim 36, further comprising a renewable energy source for providing power to the electrolysis unit.

38. The system of Claim 37, wherein the renewable energy source is selected from one or more wind turbines and one or more fuel cells.

39. The system of Claim 37, wherein the heat exchanger is adjacent the renewable energy source.

40. The system of Claim 37, wherein the one or more fuel cells are selected from proton exchange membrane fuel cells, solid oxide fuel cells and molten carbonate fuel cells.

41. The system of Claim 36, further comprising a solar energy concentrator for heating the heat-releasing energy storage medium.

42. The system of Claim 41 , wherein the solar energy concentrator is a vertically stacked solar energy concentrator.

43. The system of Claim 41 , wherein the solar energy concentrator is adjacent the heat exchanger.

44. The system of Claim 41 , wherein the heat-releasing energy storage medium comprises a salt.

45. The system of Claim 44, wherein the salt is selected from calcium chloride, barium chloride, strontium chloride, sodium bromide, potassium bromide, magnesium bromide, sodium fluoride, potassium fluoride, magnesium fluoride, lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, strontium iodide, and combinations thereof

46. A method for forming steel, comprising:

generating steam upon the application of energy from a thermal energy storage material to liquid water, the thermal energy storage material heated with the aid of solar radiation;

dissociating steam into hydrogen (H₂) and oxygen (0₂) using power provided by one or more of a renewable energy source and a fuel cell;

converting at least a portion of the H₂ and 0₂ into oxy-hydrogen; and

forming steel in a steel smelter using iron from a hydrogen-based blast furnace, wherein heat to the steel smelter is provided by the combustion of a portion of the oxy-hydrogen.

47. The method of Claim 46, further comprising contacting iron in the steel smelter with at least a portion of the 0₂.

48. A system for forming steel, comprising:

a dome or dish solar collector configured to direct solar energy to a solar energy storage material;

a heat exchanger downstream from the dome or dish solar collector, the heat exchanger having the solar energy storage material, the heat exchanger for generating steam from water; a shell-and-tube hydrogen reactor downstream from the heat exchanger, the shell-and- tube hydrogen reactor for generating hydrogen and oxygen from steam; and

a hydrogen-and-oxygen separator downstream from the shell-and-tube hydrogen reactor, the hydrogen-and-oxygen separator for separating hydrogen and oxygen.

49. The system of Claim 48, further comprising a steel smelter downstream from the shell- and-tube hydrogen reactor, the steel smelter for generating steel.

50. A system for forming hydrogen and oxygen, comprising:

a carbon- free renewable energy source for providing energy to a thermal energy storage medium in thermal communication with the carbon- free renewable energy source; a heat exchanger in proximity to the carbon- free renewable energy source, the heat exchanger for generating steam from water with the aid of energy from the thermal energy storage medium; and

a hydrogen generator downstream from the heat exchanger, the hydrogen generator for generating hydrogen and oxygen from steam formed in the heat exchanger.

1. The system of Claim 50, wherein the hydrogen generator is a fluidized bed reactor or shell-and-tube reactor.

52. A method for forming hydrogen and oxygen, comprising:

generating steam upon the application of energy from a thermal energy storage material to liquid water, the thermal energy storage material heated with the aid of a carbon- free renewable energy source;

bringing ₂ or air in contact with an iron oxide-containing material in a hydrogen to form an iron-containing material and oxygen (O2); and

bringing steam in contact with the iron-containing material in the hydrogen generator to form iron oxide-containing material and hydrogen (¾).

53. The method Claim 52, further comprising converting at least a portion of the H₂ and 0₂ into oxy-hydrogen.