GEOTHERMALLY POWERED IRON PRODUCTION SYSTEMS AND METHODS

TECHNICAL FIELD

The present disclosure relates generally to geothermal systems and related methods and more particularly to geothermally powered iron production systems and methods.

BACKGROUND

Iron production, for example, iron smelting, is traditionally an energy intensive process involving heat and mechanical means. Considerable energy is expended to supply heat and power the equipment used to perform such production. Renewable energy sources, such as solar power and wind power, can be unreliable and have relatively low power densities, such that they may be insufficient to reliably power iron production equipment. As such, production equipment typically relies on non-renewable fuels for power. There exists a need for improved iron production processes.

SUMMARY

This disclosure recognizes the previously unidentified and unmet need for a reliable renewable energy source for iron production. This disclosure provides a solution to this unmet need in the form of an iron production subsystem that is powered at least partially by geothermal energy, including one or more processes to extract iron from iron ores and to refine iron to produce pig iron, cast iron, and steel. A geothermal system harnesses heat from a geothermal resource with a sufficiently high temperature that can be used to power equipment used in iron production. More specifically, steam or another fluid may be obtained from a geothermal system and used to heat one or more vessels to obtain iron from an initial ore provided to the iron production subsystem. For example, heated fluid from a geothermal system may be used to heat a heat exchanger to maintain appropriate temperatures for smelting iron ore in a blast furnace. Additionally, one or more geothermally powered motors may be powered with fluid from a geothermal system and used to support mechanical operations of the iron production process, such as to crush and grind iron ore. Similarly, a geothermally powered motor may power a pump or conveyor that is used to move materials between different process equipment for iron production. This heated fluid is also used to supply heat to cause desirable reactions to remove impurities. One or more turbines may also be powered by the heated fluid to provide electricity for any electronic components of the iron production subsystems (e.g., electronic controllers, sensors, etc.).

Most conventional geothermal systems are used for heating applications, such as to heat a home or other space. Geothermally sourced steam has not been used to power iron production subsystems. Most previous geothermal systems tap into low temperature resources of less than 194° F. that are relatively near the surface, significantly limiting applications and locations where previous geothermal systems can be deployed. In addition to other disadvantages of previous geothermal technology, the inability of previous technology to efficiently and reliably access high-temperature underground geothermal resources renders conventional geothermal systems technologically and financially impractical.

The geothermal system of this disclosure may harness a geothermal resource with sufficiently high amounts of energy from magmatic activity such that the geothermal resource does not degrade significantly over time. This disclosure illustrates improved systems and methods for capturing energy from magma reservoirs, dikes, sills, and other magmatic formations that are significantly higher in temperature than heat sources that are accessed using previous geothermal technologies and that can contain an order of magnitude higher energy density than the geothermal fluids that power previous geothermal technologies. In some cases, the present disclosure can significantly decrease iron production costs and/or reliance on non-renewable resources for iron production subsystem operations. In some cases, the present disclosure may facilitate more efficient iron production in regions where access to reliable power is currently unavailable or transport of non-renewable fuels is challenging. The systems and methods of the present disclosure may also or alternatively aid in decreasing carbon emissions.

In some embodiments, the geothermal system that powers the disclosed iron production subsystems is a closed geothermal system that exchanges heat with an underground geothermal reservoir. The geothermal reservoir may be magma. For example, an underground geothermal reservoir, such as a magma reservoir, may facilitate the generation of high-temperature, high-pressure steam, while avoiding problems and limitations associated with previous geothermal technology. The geothermal systems of this disclosure generally include a wellbore that extends from a surface into an underground thermal reservoir, such as a magma. A closed heat-transfer loop is employed in which a heat transfer fluid is pumped into the wellbore, heated via contact with the underground thermal reservoir, and returned to the surface to power an iron production subsystem(s) located within a sufficient proximity to the wellbore, as discussed above.

Certain embodiments may include none, some, or all of the above technical advantages. One or more technical advantages may be readily apparent to one skilled in the art from figures, description, and claims included herein.

BRIEF DESCRIPTION OF THE FIGURES

For a more complete understanding of the present disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings and detailed description, in which like reference numerals represent like parts.

FIG. 1 illustrates a diagram of underground regions in the Earth.

FIG. 2 illustrates a diagram of one embodiment of a conventional geothermal system.

FIG. 3 illustrates a diagram of an exemplary improved geothermal system of this disclosure.

FIG. 4 illustrates a diagram of an exemplary system in accordance with the disclosed principles in which iron production is powered by the improved geothermal system of FIG. 3.

FIG. 5 illustrates a first embodiment of a geothermally powered iron production system, construction in accordance with the disclosed principles.

FIG. 6 illustrates a second embodiment of a geothermally powered iron production system, construction in accordance with the disclosed principles.

FIG. 7 illustrates a third embodiment of a geothermally powered iron production system, construction in accordance with the disclosed principles.

FIG. 8 illustrates a schematic diagram of an example thermal process system 304 of FIGS. 3 and 4, which may be implemented with an iron production system or related method in accordance with the disclosed principles.

DETAILED DESCRIPTION

Embodiments of the present disclosure and its advantages will become apparent from the following detailed description when considered in conjunction with the accompanying figures. In the figures, each identical, or substantially similar component that is illustrated in various figures is represented by a single numeral or notation. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure.

The present disclosure includes unexpected observations, which include the following: (1) magma reservoirs can be located at relatively shallow depths of less than 2.5 km; (2) the top layer of a magma reservoir may have relatively few crystals with little or no mush zone; (3) rock near or around magma reservoirs is generally not ductile and can support fractures; (4) a magma reservoir does not decline in thermal output over at least a two-year period; (5) eruptions at drill sites into magma reservoirs are unlikely (e.g., eruptions have not happened at African and Icelandic drill sites in over 10,000 years and it is believed a Kilauea, Hawaii drill site has never erupted); and (6) drilling into such reservoirs can be reasonably safe.

As used herein, “magma” refers to extremely hot liquid and semi-liquid rock under the Earth's surface. Magma is formed from molten or semi-molten rock mixture found typically between 1 km to 10 km under the surface of the Earth. As used herein, “borehole” refers to a hole that is drilled to aid in the exploration and recovery of natural resources, including oil, gas, water, or heat from below the surface of the Earth. As used herein, a “wellbore” refers to a borehole either alone or in combination with one or more other components disposed within or in connection with the borehole in order to perform exploration and/or recovery processes. As used herein, “fluid conduit” refers to any structure, such as a pipe, tube, or the like, used to transport fluids. As used herein, “heat transfer fluid” refers to a fluid, e.g., a gas or liquid, that takes part in heat transfer by serving as an intermediary in cooling on one side of a process, transporting and storing thermal energy, and heating on another side of a process. Heat transfer fluids are used in processes requiring heating or cooling.

FIG. 1 is a partial cross-sectional diagram of the Earth depicting underground formations that can be tapped by geothermal systems of this disclosure (e.g., for generating geothermal power). The Earth is composed of an inner core 102, outer core 104, lower mantle 106, transition zone 108, upper mantle 110, and crust 112. There are places on the Earth where magma reaches the surface of the crust 112 forming volcanos 114. However, in most cases, magma approaches only within a few miles or less from the surface. This magma can heat ground water to temperatures sufficient for certain geothermal power production. However, for other applications, such as geothermal energy production, more direct heat transfer with the magma is desirable.

FIG. 2 illustrates a conventional geothermal system 200 that harnesses energy from heated ground water for power generation. The conventional geothermal system 200 is a “flash-plant” that generates power from a high-temperature, high-pressure geothermal water extracted from a production well 202. The production well 202 is drilled through rock layer 208 and into the geothermal fluid layer 210 that serves as the source of geothermal water. The geothermal water is heated indirectly via heat transfer with intermediate layer 212, which is in turn heated by magma reservoir 214. Convective heat transfer (illustrated by the arrows indicating that hotter fluids rise to the upper portions of their respective layers before cooling and sinking, then rising again) may facilitate heat transfer between these layers. Geothermal water from the geothermal fluid layer 210 flows to the surface 216 and is used for geothermal power generation. The geothermal water (and possibly additional water or other fluids) is then injected back into the geothermal fluid layer 210 via an injection well 204.

The configuration of conventional geothermal system 200 of FIG. 2 suffers from drawbacks and disadvantages, as recognized by this disclosure. For example, in contrast to the improved systems of this disclosure, the conventional geothermal system 200 cannot achieve sufficiently high temperatures for efficiently facilitating iron production processes. As another example, because geothermal water is a polyphase fluid (i.e., not pure water), the geothermal water flashes at various points along its path up to the surface 216, creating water hammer, which results in a large amount of noise and potential damage to system components. The geothermal water is also prone to cause scaling and corrosion of system components. Chemicals may be added to partially mitigate these issues, but this may result in considerable increases in operational costs and increased environmental impacts, since these chemicals are generally introduced into the environment via injection well 204.

Example Improved Geothermal System

FIG. 3 illustrates an example magma-based geothermal system 300 of this disclosure. The magma-based geothermal system 300 includes a wellbore 302 that extends from the surface 216 at least partially into the magma reservoir 214. The magma-based geothermal system 300 is a closed system in which a heat transfer fluid is provided down the wellbore 302 to be heated and returned to a thermal process system 304 (e.g., for power generation and/or any other thermal processes of interest). As such, geothermal water is not extracted from the Earth, resulting in significantly reduced risks associated with the conventional geothermal system 200 of FIG. 2, as described further below. Heated heat transfer fluid is provided to the thermal process system 304. The thermal process system 304 is generally any system that uses the heat transfer fluid to drive a process of interest. For example, the thermal process system 304 may include an electricity generation system and/or support thermal processes requiring higher temperatures/pressures than could be reliably or efficiently obtained using previous geothermal technology, such as the conventional geothermal system 200 of FIG. 2. Further details of components of an example thermal process system 304 are provided with respect to FIG. 10 below.

The magma-based geothermal system 300 provides technical advantages over previous geothermal systems, such as the conventional geothermal system 200 of FIG. 2. The magma-based geothermal system 300 can achieve higher temperatures and pressures for increased energy generation (and/or for more effectively driving other thermal processes). For example, because of the high energy density of magma in magma reservoir 214 (e.g., compared to that of geothermal water of the geothermal fluid layer 210), wellbore 302 can generally create the power of many wells of the conventional geothermal system 200 of FIG. 2. Furthermore, the magma-based geothermal system 300 has little or no risk of thermal shock-induced earthquakes, which might be attributed to the injection of cooler water into a hot geothermal zone, as is performed using the conventional geothermal system 200 of FIG. 2. The heat transfer fluid is generally not substantially released into the geothermal zone, resulting in a decreased environmental impact and decreased use of costly materials (e.g., chemical additives that are used and introduced to the environment in great quantities during some conventional geothermal operations). The magma-based geothermal system 300 may also have a simplified design and operation compared to those of previous systems. For instance, fewer components and reduced complexity may be needed at the thermal process system 304 because only clean heat transfer fluid (e.g., steam) reaches the surface 216. There may be no need or a reduced need to separate out solids or other impurities that are common to geothermal water. The example magma-based geothermal system 300 may include further components not illustrated in FIG. 3.

Further details and examples of different configurations of geothermal systems and methods of their preparation and operation are described in U.S. patent application Ser. No. 18/099,499, filed Jan. 20, 2023, and titled “Geothermal Power from Superhot Geothermal Fluid and Magma Reservoirs”; U.S. patent application Ser. No. 18/099,509, filed Jan. 20, 2023, and titled “Geothermal Power from Superhot Geothermal Fluid and Magma Reservoirs”; U.S. patent application Ser. No. 18/099,514, filed Jan. 20, 2023, and titled “Geothermal Power from Superhot Geothermal Fluid and Magma Reservoirs”; U.S. patent application Ser. No. 18/099,518, filed Jan. 20, 2023, and titled “Geothermal Power from Superhot Geothermal Fluid and Magma Reservoirs”; U.S. patent application Ser. No. 18/105,674, filed Feb. 3, 2023, and titled “Wellbore for Extracting Heat from Magma Chambers”; U.S. patent application Ser. No. 18/116,693, filed Mar. 2, 2023, and titled “Geothermal Systems and Methods with an Underground Magma Chamber”; U.S. patent application Ser. No. 18/116,697, filed Mar. 2, 2023, and titled “Method and System for Preparing a Geothermal System with a Magma Chamber”; and U.S. Provisional Patent Application No. 63/444,703, filed Feb. 10, 2023, and titled “Geothermal Systems and Methods Using Energy from Underground Magma Reservoirs”, the entireties of each of which are hereby incorporated by reference.

Geothermally Powered Iron Production

FIG. 4 illustrates an example combined geothermal and iron production system 400 of this disclosure. The combined geothermal and iron production system 400 includes all or a portion of the components of the magma-based geothermal system 300 described above with respect to FIG. 3, as well as geothermally powered iron production subsystem 500 for producing iron. Exemplary embodiments of the geothermally powered iron production subsystem 500 are described in greater detail below with reference to FIGS. 5-7. The combined geothermal and iron production system 400 may include all or a portion of the thermal process system 304. In operation, heat transfer fluid is injected into the wellbore 302, which extends from the surface 216 into the magma reservoir 214 underground. The heated heat transfer fluid can be conveyed to the thermal process system 304 as heat transfer fluid 404a that can be used to drive processes, such as the generation of electricity by turbines 1004 and 1008 in FIG. 10. Heat transfer fluid 404a may be referred to in the alternative as a stream of heat transfer fluid 404a. Heat transfer fluid 404c, which can be formed from any remaining amount of heat transfer fluid 404a (e.g., steam) exiting from the thermal process system 304 and/or the wellbore bypass stream, i.e., heat transfer fluid 404b, is provided to the geothermally powered iron production subsystem 500. The electricity 408 may be used in addition to or in place of heat transfer fluid 404c for powering electrical and mechanical processes in the geothermally powered iron production subsystem 500.

As described in greater detail below with respect to FIGS. 5-7, the geothermally powered iron production subsystem 500 uses the heat transfer fluid 404c to provide a heat source for producing iron 562. For example, a motor of the geothermally powered iron production subsystem 500 may be powered by the heat of heat transfer fluid 404c, and the motor may provide motion to a hopper 506, crusher 508, conveyor 546, fluid pump(s), and/or the like of the geothermally powered iron production subsystem 500 (see FIGS. 5-7 and corresponding descriptions below). As another example, the geothermally powered iron production subsystem 500 may include a fluid pump with a motor that is powered at least in part by the heat transfer fluid (e.g., steam) heated in the wellbore 302. As another example, the geothermally powered iron production subsystem 500 may include a motor that aids in moving a mixer in a precipitation tank and is powered by heat transfer fluid (e.g., steam) heated in the wellbore 302. More detailed examples of operations of geothermally powered iron production subsystem 500 are provided below with respect to FIGS. 5-7.

Heat transfer fluid (e.g., condensed steam) that is cooled and/or or decreased in pressure after powering the geothermally powered iron production subsystem 500 may be returned to the wellbore 302 as heat transfer fluid 406a. For instance, as shown in the example of FIG. 4, a stream of return heat transfer fluid 406c may be provided back to the thermal process system 304, used to drive one or more reactions or processes, and then expelled as heat transfer fluid 406a for return to the wellbore 302. The heat transfer fluid 406a can also include a bypass stream of heat transfer fluid 406b, which can be formed from heat transfer fluid 406c, in whole or in part. Restated, thermally processed return stream of heat transfer fluid 406a includes heat transfer fluid (e.g., condensed steam) from the thermal process system 304 and/or the bypass stream of heat transfer fluid 406b. Thermally processed return stream of heat transfer fluid 406a that is sent back to the wellbore 302 may be water (or another heat transfer fluid), while the stream of heat transfer fluid 404a received from the wellbore 302 is steam (or another heat transfer fluid at an elevated temperature and/or pressure). While the example of FIG. 4 includes the thermal process system 304 of FIG. 3, in some cases, the combined geothermal and iron production system 400 may exclude all or a portion of the thermal process system 304. For example, the wellbore stream of heat transfer fluid 404a from the wellbore 302 may be provided directly to the geothermally powered iron production subsystem 500 (see wellbore bypass stream of heat transfer fluid 404b described above).

Heat transfer fluid in streams 404a-c and 406a-c may be any appropriate fluid for absorbing heat within the wellbore 302 and driving operations of the geothermally powered iron production subsystem 500 and, optionally the thermal process system 304. For example, the heat transfer fluid may include water, a brine solution, one or more refrigerants, a thermal oil (e.g., a natural or synthetic oil), a silicon-based fluid, a molten salt, a molten metal, or a nanofluid (e.g., a carrier fluid containing nanoparticles). A molten salt is a salt that is a liquid at the high operating temperatures experienced in the wellbore 302 (e.g., at temperatures between 1,600 and 2,300° F.). In some cases, an ionic liquid may be used as the heat transfer fluid. An ionic liquid is a salt that remains a liquid at more modest temperatures (e.g., at or near room temperature). In some cases, a nanofluid may be used as the heat transfer fluid. The nanofluid may be a molten salt or ionic liquid with nanoparticles, such as graphene nanoparticles, dispersed in the fluid. Nanoparticles have at least one dimension of 100 nanometers (nm) or less. The nanoparticles increase the thermal conductivity of the molten salt or ionic liquid carrier fluid. This disclosure recognizes that molten salts, ionic liquids, and nanofluids can provide improved performance as heat transfer fluids in the wellbore 302. For example, molten salts and/or ionic liquids may be stable at the high temperatures that can be reached in the wellbore 302. The high temperatures that can be achieved by these materials not only facilitate increased energy extraction but also can drive thermal processes that were previously inaccessible using previous geothermal technology. The heat transfer fluid may be selected at least in part to limit the extent of corrosion of surfaces of the combined geothermal and iron production system 400. As an example, the heat transfer fluid may be water. The water is supplied to the wellbore 302 as stream of heat transfer fluid 406a in the liquid phase and is transformed into steam within the wellbore 302. The steam is received as stream of heat transfer fluid 404a and used use to drive the geothermally powered iron production subsystem 500.

First Embodiment of an Exemplary Geothermally Powered Iron Production System

FIG. 5 illustrates a first embodiment of a geothermally powered iron production subsystem 500A, designed and constructed in accordance with the disclosed principles. The subsystem 500A of FIG. 5 is provided as an example of the subsystem 500 of FIG. 4. The geothermally powered iron production subsystem 500A may include more or fewer components, and the components may be arranged in different configurations in order to produce iron.

This embodiment of the example geothermally powered iron production subsystem 500A includes a hopper 506 and a crusher 508 that receive iron ore 504a and produces crushed iron ore 504b. As illustrated in broken line, these components and other components of the subsystem 500A may optionally be powered at least partially by geothermal energy from a heat transfer fluid 404c (e.g., steam), which obtained its heat from the magma reservoir 214 via the stream of heat transfer fluid 404a. This heat transfer fluid 404c may be used directly to power a motor 502 that is used to operate the crusher 508. In other embodiments, the motor 502 may alternatively be powered by electricity 408 or a traditional means of power. This heat transfer fluid 404c may be used directly to heat components in the geothermally powered iron production subsystem 500A or to heat a secondary heat transfer fluid. Such a secondary heat transfer fluid may be any similarly suitable fluid as chosen in the primary heat transfer fluid 404c. The heat transfer fluid 404c or secondary heat transfer fluid may be used to heat components or may be converted to mechanical or electrical energy to perform operations in the geothermally powered iron production subsystem 500A.

During operation of the geothermally powered iron production subsystem 500A, the iron ore 504a enters the hopper 506 and is crushed and ground by the crusher 508. The hopper 506 can be any appropriate type of open funnel that receives iron ore 504a. It may also contain a screen or a feeder, as desired. The geothermally powered motor 502 coupled to the crusher 508 powers the crusher 508, as well as possibly any other components employed for operation of the crusher 508. The geothermally powered motor 502 can be coupled to system components, such as the crusher 508, using conventional means, e.g., mechanical, electrical, pneumatic, etc., which are omitted in FIG. 5 for the sake of simplicity. The crusher 508 can be any appropriate type of machine that operates by rolling, impacting, milling, vibrating, and/or grinding. For example, the crusher 508 may be a jaw crusher, impact crusher, or ball mill. The geothermally powered motor 502 may be geothermally powered directly by the heat transfer fluid 404c that is heated by the magma reservoir 214. An example of a geothermally powered motor is described in U.S. Provisional Patent Application No. 63/448,929, filed Feb. 28, 2023, and titled “Drilling Equipment Powered by Geothermal Energy,” the entirety of which is incorporated herein by reference.

The crushed iron ore 504b is fed into a blast furnace 510 along with, for example, limestone and coke 512, which are typically combined with the iron ore in iron production processes. The blast furnace 510 is used to heat the iron ore 504b, limestone and coke 512 to produce usable iron, as described in further detail below. To heat the blast furnace 510, in this embodiment of a subsystem 500A as disclosed herein, an air compressor 514 is used to introduce compressed air into the blast furnace 510. The compressed air is part of a heat source for heating materials in the blast furnace 510. The air compressor 514, in some embodiments, may also be powered by a geothermally powered motor using heat transfer fluid 404c. The air compressor 514 forces compressed air into a heat exchanger 516 so that it is heated for use as heat for the blast furnace 510. Specifically, heat transfer fluid 404c that is heated by the magma in the manner discussed above is fed to the heat exchanger 516, and the heat exchanger 516 heats the input compressed air as it passes through the heat exchanger 516 from the air compressor 514. This heated compressed air is input into the blast furnace 510 to heat the iron ore, limestone, and coke to produce the iron.

Within the blast furnace 510, a layer of iron ore, limestone, and coke 524 floats above the melting zone 518 until it is melted by the heat within the blast furnace 510. Heating the iron ore, limestone, and coke in this manner causes chemical reactions within the blast furnace 510 to produce pig iron 520 from the iron ore 504. More specifically, iron ore contains iron-bearing minerals hematite (Fe₂O₃) and magnetite (Fe₃O₄). Compressed air contains O₂that fuels combustion inside the blast furnace 510. Coke contains C, which causes reduction of the Fe. Lime/limestone (CaCO₃) is added to remove impurities from the molten iron ore (e.g., Si) leaving behind only Fe (iron). Accordingly, the heated compressed air causes coke and oxygen combustion as follows:

embedded image

Additionally, reduction of iron ore within the blast furnace 510 is as follows:

embedded image

Iron refining with limestone within the blast furnace 510, and thus the removal of impurities from the blast furnace 510 via slag, is as follows:

embedded image

The heated combination of iron ore, limestone, and coke in the melting zone 518 of the blast furnace 510 results, eventually via these chemical reactions, in the creation of molten pig iron 520 and molten slag 522. Slag 522 is a silicate waste product that forms as a molten layer on top of a molten pig iron layer 520 at the bottom of the blast furnace 510. Molten slag 522 is less dense than pig iron, and thus it floats on top of the pig iron, which allows both layers to be tapped to remove them periodically from the blast furnace 510. Thus, throughout the geothermally powered heating process, the molten pig iron 520 is periodically collected (“tapped”) through an iron tap 526. Also, molten slag 522 is periodically collected through a slag tap 528 as the blast furnace 510 continues to heat the iron ore, limestone and coke 512. Exhaust fumes form within the blast furnace 510 as a byproduct of the chemical reactions among the iron ore, limestone and coke 512. These exhaust fumes are removed from the blast furnace 510 by an exhaust system 530, which may also be powered by a geothermally powered motor in the manner discussed above with respect to the air compressor 514. For example, heat transfer fluid may be used to power a geothermally power motor within the exhaust system 530 in order to pump the exhaust fumes from the blast furnace 510.

Second Embodiment of an Exemplary Geothermally Powered Iron Production System

FIG. 6 illustrates a second exemplary embodiment of a geothermally powered iron production subsystem 500B, designed and constructed in accordance with the disclosed principles. The subsystem 500B of FIG. 6 is again provided as an example of the subsystem 500 of FIG. 4. As before, this embodiment of the geothermally powered iron production subsystem 500B may include more or fewer components, and the components may be arranged in different configurations in order to produce iron.

This embodiment of the example geothermally powered iron production subsystem 500B also includes a hopper 506 and a crusher 508 that receive iron ore 504a and produces crushed iron ore 504b. As illustrated in broken line, these components and other components of the subsystem 500B may optionally be powered at least partially by geothermal energy from a heat transfer fluid 404c (e.g., steam), which obtains its heat from the magma reservoir 214 via the stream of heat transfer fluid 404a. This heat transfer fluid 404c may be used directly to power a motor 502 that is used to operate the crusher 508. In other embodiments, the motor 502 may alternatively be powered by traditional means of power as well. This heat transfer fluid 404c may be used directly to heat components in the geothermally powered iron production subsystem 500B or to heat a secondary heat transfer fluid. Such a secondary heat transfer fluid may be any similarly suitable fluid as chosen in the primary heat transfer fluid 404c. The heat transfer fluid 404c or secondary heat transfer fluid may be used to heat components or may be converted to mechanical or electrical energy to perform operations in the geothermally powered iron production subsystem 500B.

During operation of the geothermally powered iron production subsystem 500B, the iron ore 504a enters the hopper 506 and is crushed and ground by the crusher 508. The hopper 506 can be any appropriate type of open funnel that receives iron ore 504a. It may also contain a screen or a feeder, as desired. The geothermally powered motor 502 coupled to the crusher 508 powers the crusher 508, as well as possibly any other components employed for operation of the crusher 508. The geothermally powered motor 502 can be coupled to system components, such as the crusher 508, using conventional means, e.g., mechanical, electrical, pneumatic, etc., which are omitted in FIG. 6 for the sake of simplicity. The crusher 508 can be any appropriate type of machine that operates by rolling, impacting, milling, vibrating, and/or grinding. For example, the crusher 508 may again be a jaw crusher, impact crusher, or ball mill. As before, the geothermally powered motor 502 may be geothermally powered directly by the heat transfer fluid 404c that is heated by the magma reservoir 214, as described above.

In this illustrated embodiment, the heat exchanger 516 is located within the melting zone 518 of the blast furnace 510. To withstand the extreme temperatures within the blast furnace 510, the heat exchanger 516 in this embodiment of the iron producing subsystem 500B may be constructed from materials suitable for prolonged use within the melting zone 518. In some embodiments, the external surfaces of the heat exchanger 516 itself may be constructed from materials capable of withstanding these extreme temperatures. In other embodiments, the heat exchanger 516 may be placed within a vessel or other structure 516a that is constructed from materials capable of withstanding these extreme temperatures. For example, the structure may be comprised of one or more of brick, stone, ceramic, or a metal. In such embodiments, the heat exchanger 516 directly heats the structure 516a in which it is placed, and this vessel or structure 516a in turn heats the iron ore 504b, limestone and coke 512 within the melting zone 518.

Once melted, the iron ore, limestone, and coke again chemically reacts in the manner discussed above to produce pig iron 520. Specifically, within the blast furnace 510, a layer of iron ore, limestone, and coke 524 floats above the melting zone 518 until it is melted by the heat provided by the geothermally powered heat exchanger 516. The heated combination of iron ore, limestone, and coke in the melting zone 518 of the blast furnace 510 results, again via the chemical reactions discussed above, in the creation of molten pig iron 520 and molten slag 522. The molten pig iron 520 is again periodically collected through an iron tap 526, and molten slag 520 is periodically collected through a slag tap 528 as the blast furnace 510 continues to melt the iron ore, limestone and coke 512. Exhaust fumes again form within the blast furnace 510 as a byproduct of the chemical reactions among the iron ore, limestone and coke 512. These exhaust fumes are removed from the blast furnace 510 by the exhaust system 530, which may again be powered by a geothermally powered motor.

Third Embodiment of an Exemplary Geothermally Powered Iron Production System

FIG. 7 illustrates a third exemplary embodiment of a geothermally powered iron production subsystem 500C, designed and constructed in accordance with the disclosed principles. The subsystem 500C of FIG. 7 is again provided as an example of the subsystem 500 of FIG. 4. As before, this embodiment of the geothermally powered iron production subsystem 500C may include more or fewer components, and the components may be arranged in different configurations in order to produce iron.

This third embodiment of the exemplary geothermally powered iron production subsystem 500C again includes a hopper 506 and a crusher 508 that receive iron ore 504a and produces crushed iron ore 504b. As illustrated in broken line, these components and other components of the subsystem 500C may optionally be powered at least partially by geothermal energy from a heat transfer fluid 404c (e.g., steam), which obtains its heat from the magma reservoir 214 via the stream of heat transfer fluid 404a. This heat transfer fluid 404c may again optionally be used directly to power a motor 502 that is used to operate the crusher 508. In other embodiments, the motor 502 may be powered by traditional means of power as well. This heat transfer fluid 404c may be used directly to heat components in the geothermally powered iron production subsystem 500C or to heat a secondary heat transfer fluid, also as before. Such a secondary heat transfer fluid may be any similarly suitable fluid as chosen in the primary heat transfer fluid 404c. The heat transfer fluid 404c or secondary heat transfer fluid may be used to heat components or may be converted to mechanical or electrical energy to perform operations in the geothermally powered iron production subsystem 500C.

During operation of this third embodiment of the geothermally powered iron production subsystem 500C, the iron ore 504a enters the hopper 506 and is crushed and ground by the crusher 508. As in other embodiments, the hopper 506 can be any appropriate type of open funnel that receives iron ore 504a. It may also contain a screen or a feeder, as desired. The geothermally powered motor 502 coupled to the crusher 508 powers the crusher 508, as well as possibly any other components employed for operation of the crusher 508. The geothermally powered motor 502 can be coupled to system components, such as the crusher 508, using conventional means, e.g., mechanical, electrical, pneumatic, etc., which are omitted in FIG. 7 for the sake of simplicity. The crusher 508 can be any appropriate type of machine that operates by rolling, impacting, milling, vibrating, and/or grinding. For example, the crusher 508 may again be a jaw crusher, impact crusher, or ball mill. As before, the geothermally powered motor 502 may be geothermally powered directly by the heat transfer fluid 404c that is heated by the magma reservoir 214, as described throughout the present disclosure.

As in other embodiments, the crushed iron ore 504b is fed into a blast furnace 510 along with limestone and coke 512 for the iron production process. The blast furnace 510 is again used to heat the iron ore 504b, limestone and coke 512 to produce usable iron, as described in detail above. However, to heat the blast furnace 510 in this embodiment of a subsystem 500C, an air compressor 514 is again used to introduce compressed air into the heat exchanger 516. The air compressor 514 may again in some embodiments be powered by a geothermally powered motor using heat transfer fluid 404c. The air compressor 514 forces compressed air into the heat exchanger 516 so that it is heated for use to heat the blast furnace 510. Specifically, heat transfer fluid 404c that is heated by the magma in the manner discussed above is fed to the heat exchanger 516, and the heat exchanger 516 heats the input compressed air as it is input to the heat exchanger 516 from the air compressor 514. However, instead of injecting this heated compressed air into the blast furnace 510 as in the embodiment discussed above, the heated compressed air in this embodiment is used to heat the heat exchanger 516 itself. As such, the heat exchanger 516 acts as a heat source for the blast furnace 510.

This embodiment of the heat exchanger 516 surrounds blast furnace 510 to heat the blast furnace 510 in order to heat the iron ore, limestone, and coke to produce the iron. In this manner, the heat exchanger 516 directly heats the blast furnace 510 as it is heated by the heat transfer fluid. In one embodiment, the heat exchanger 516 is formed around and directly in contact with the exterior of the blast furnace 510 to directly heat the blast furnace 510 and its contents. In other embodiments, the heat exchanger 516 is positioned around the exterior of the blast furnace 510 but not in direct contact with the exterior. Thus, in such embodiments the heat exchanger 516 heats the blast furnace 510 indirectly. In yet other embodiments, the heat exchanger 516 is in contact with and heats an intermediate liner or structure (not illustrated) between the heat exchanger 516 and the blast furnace 510 in order to produce the iron.

As with other embodiments disclosed herein, within the blast furnace 510, a layer of iron ore, limestone, and coke 524 floats above the melting zone 518 until it is melted by the heat within the blast furnace 510 provided by the heat exchanger 516. The heated combination of iron ore, limestone, and coke in the melting zone 518 of the blast furnace 510 results, eventually the above-described chemical reactions, in the creation of molten pig iron 520 and molten slag 522. Throughout the iron producing process, the molten pig iron 520 is collected through an iron tap 526, and molten slag 520 is periodically removed via a slag tap 528. As before, exhaust fumes form within the blast furnace 510 as a byproduct of the chemical reactions among the iron ore, limestone and coke 512, and these exhaust fumes are removed from the blast furnace 510 by an exhaust system 530. The exhaust system 530, also as discussed above, may also be powered by a geothermally powered motor, employing heat transfer fluid in a power generation process within the exhaust system 530, in order to pump the exhaust fumes from the blast furnace 510.

While the example embodiments of FIGS. 5-7 are described separately, it should be understood that components and/or operations of these example subsystems 500A, 500B, and 500C can be combined. For example, the geothermally powered iron production subsystem 500 of FIG. 4 can employ one or more of (i) the heated compressed air of the subsystem 500A of FIG. 5, (i) the external heat exchanger 516 of the subsystem 500B of FIG. 6, and (iii) the internal heat exchanger 516 of the subsystem 500C of FIG. 7 as a heat source for the blast furnace 510.

Example Thermal Process System

FIG. 8 shows a schematic diagram of an example thermal process system 304 of FIGS. 3 and 4, which may be implemented with an iron production system or related method in accordance with the disclosed principles. The thermal process system 304 includes a condenser 802, a first turbine set 804, a second turbine set 808, a high-temperature/pressure thermochemical process 812, a medium-temperature/pressure thermochemical process 814, and one or more lower temperature/pressure processes 816a,b. The thermal process system 304 may include more or fewer components than are shown in the example of FIG. 8. For example, a thermal process system 304 used for power generation alone may omit the high-temperature/pressure thermochemical process 812, medium-temperature/pressure thermochemical process 814, and lower temperature/pressure processes 816a,b. Similarly, a thermal process system 304 that is not used for power generation may omit the turbine sets 804, 808. As a further example, if heat transfer fluid is known to be received only in the gas phase, the condenser 802 may be omitted in some cases. The ability to tune the properties of the heat transfer fluid received from the unique wellbore 302 of FIGS. 3 and 4 facilitates improved and more flexible operation of the thermal process system 304. For example, the depth of the wellbore 302, the residence time of heat transfer fluid in the magma reservoir 214, the pressure achieved in the wellbore 302, and the like can be selected or adjusted to provide desired heat transfer fluid properties at the thermal process system 304.

In the example of FIG. 8, the condenser 802 is connected to the wellbore 302 that extends between a surface and the underground magma reservoir. The condenser 802 separates a gas-phase heat transfer fluid (e.g., steam) from liquid-phase heat transfer fluid (e.g., condensate formed from the gas-phase heat transfer fluid). The condenser 802 may be a steam separator. A stream 820 received from the wellbore 302 may be provided to the condenser 802. In some cases, all of stream 818 is provided in stream 820. In other cases, a fraction or none of stream 818 is provided to the condenser 802. Instead, all or a portion of the stream 818 may be provided as stream 828 which may be provided to the first turbine set 804 and/or to a high-pressure thermal process 812 in stream 829. The thermal process 812 may be a thermochemical reaction requiring high temperatures and/or pressures (e.g., temperatures of between 500° F. and 2,000° F. and/or pressures of between 1,000 psig and 4,500 psig), such as the geothermally powered iron production subsystem 500. One or more valves (not shown for conciseness) may be used to control the direction of stream 820 to the condenser 802, first turbine set 804, and/or thermal process 812. A gas-phase stream 822 of heat transfer fluid from the condenser may be sent to the first turbine set 804 and/or the thermal process 812 via stream 826. A liquid-phase stream 824 of heat transfer fluid from the condenser 802 may be provided back to the wellbore 302.

The first turbine set 804 includes one or more turbines 806a,b. In the example of FIG. 8, the first turbine set includes two turbines 806a,b. However, the first turbine set 804 can include any appropriate number of turbines for a given need. The turbines 806a,b may be any known or yet to be developed turbine for electricity generation. The turbine set 804 is connected to the condenser 802 and is configured to generate electricity from the gas-phase heat transfer fluid (e.g., steam) received from the condenser 802 (stream 822). A condensate stream 830 exits the set of turbines 804. The condensate stream 830 may be provided back to the wellbore 302.

If the heat transfer fluid is at a sufficiently high temperature, as may be uniquely and more efficiently possible using the wellbore 302, a stream 832 of gas-phase heat transfer fluid may exit the first turbine set 804. Stream 832 may be provided to a second turbine set 808 to generate additional electricity. The turbines 808a,b of the second turbine set 808 may be the same as or similar to turbines 806a,b, described above.

All or a portion of stream 832 may be sent as gas-phase stream 834 to a thermal process 814. Process 814 is generally a process requiring gas-phase heat transfer fluid at or near the conditions of the heat transfer fluid exiting the first turbine set 804. For example, the thermal process 814 may include one or more thermochemical processes requiring steam or another heat transfer fluid at or near the temperature and pressure of stream 832 (e.g., temperatures of between 250° F. and 1,500° F. and/or pressures of between 500 psig and 2,000 psig). The second turbine set 808 may be referred to as “low pressure turbines” because they operate at a lower pressure than the first turbine set 804. Condensate from the second turbine set 808 is provided back to the wellbore 302 via stream 836.

An effluent stream 838 from the second turbine set 808 may be provided to one or more thermal processes 816a,b. Thermal processes 816a,b generally require less thermal energy than processes 812 and 814, described above (e.g., processes 816a,b may be performed temperatures of between 220° F. and 700° F. and/or pressures of between 15 psig and 120 psig). As an example, processes 816a,b may include water distillation processes, heat-driven chilling processes, space heating processes, agriculture processes, aquaculture processes, and/or the like. For instance, an example heat-driven chiller process 816a may be implemented using one or more heat driven chillers. Heat driven chillers can be implemented, for example, in data centers, crypto-currency mining facilities, or other locations in which undesirable amounts of heat are generated. Heat driven chillers, also conventionally referred to as absorption cooling systems, use heat to create chilled water. Heat driven chillers can be designed as direct-fired, indirect-fired, and heat-recovery units. When the effluent includes low pressure steam, indirect-fired units may be preferred. An effluent stream 840 from all processes 812, 814, 816a,b, may be provided back to the wellbore 302.

The geothermally powered iron production subsystem 500 can achieve high temperatures via heat transfer fluids in contact with a magma chamber or in contact with heat transfer fluids heated by a magma chamber for operations that require heating. This ability to obtain high heat transfer allows deployment of alternative methods of iron production that were previously too energy intensive to practically implement. More specifically, in accordance with the disclosed principles, a geothermally powered heat exchanger may be used to heat a blast furnace used in the smelting and production of iron. In various embodiments, the heat exchanger is heated via geothermally heated heat exchange fluid to heat the blast furnace. For example, compressed air can be fed into the heat exchanger and heated prior to entering blast furnace, or the heat exchanger can itself be used to internally heat the air inside the blast furnace, or the heat exchanger can be used to externally heat the blast furnace to heat the air and iron production components within the blast furnace.

Additionally, use of geothermally powered systems not only in the overall iron production subsystems but also in the use of one or more individual subsystem components as disclosed herein may reduce waste in several ways. For example, the iron production systems described herein may use geothermally powered motors to move the iron ore through a hopper, rotate a crusher to crush the iron ore, power an exhaust system, and/or power an air compressor. An iron production system in accordance with the disclosed principles may further include the use of geothermal power, via heat exchange fluid heated by a magma reservoir, to power one or more of these iron production system components.

Further advantages are achieved by reducing carbon emissions from the use of geothermal processes in subsystem components during iron smelting. Operating subsystems and subsystem components require large amounts of electrical power. Coal-fired generation emits tonnes of carbon dioxide per tonne of iron produced, and the principles disclosed herein can achieve the same or better results in iron production without this release of carbon dioxide. Accordingly, as described in this disclosure, geothermal energy can power iron production subsystems to produce less waste and less pollution (e.g., without using coal-fired processes or with a significant decrease in the use of such processes). As such, this disclosure may facilitate iron production with a decreased environmental impact and decreased use of costly materials.

While the example systems of this disclosure are described as employing heating through thermal contact with a magma reservoir 214, it should be understood that this disclosure also encompasses similar systems in which another thermal reservoir or heat source is harnessed. For example, heat transfer fluid may be heated by underground water at an elevated temperature. As another example, heat transfer fluid may be heated by radioactive material emitting thermal energy underground. As yet another example, heat transfer fluid may be heated by lava, for example, in a lava lake or other formation. As such, the magma reservoir 214 of FIGS. 3 and 4 may represent any thermal reservoir or heat source that is capable of heating heat transfer fluid to achieve desired properties (e.g., of temperature and pressure). Furthermore, the thermal reservoir or heat source may be naturally occurring or artificially created (e.g., by introducing heat underground that can be harnessed at a later time for energy generation or other thermal processes).

Additional Embodiments

The following descriptive embodiments are offered in further support of the one or more aspects of the present disclosure.

Embodiment 1. A geothermally powered iron production subsystem, comprising:

- a hopper comprising a vessel configured to receive iron ore and direct the received iron ore through a crusher;
- the crusher configured to crush at least a portion of the received iron ore;
- a blast furnace configured to receive the crushed iron ore and to further receive limestone and coke, the blast furnace further configured to melt the crushed iron ore, limestone, and coke using heat; and
- a heat source comprising a heat exchanger receiving a heated heat transfer fluid and configured to provide the heat to the blast furnace at least in part using the heated heat transfer fluid, wherein the system optionally includes any one or more of the following limitations:
- further comprising an air compressor system configured to provide air to the heat exchanger; wherein the heat exchanger is further configured to heat the provided air, and to provide the heated provided air to the blast furnace as the heat;
- wherein the heat exchanger is positioned within the blast furnace to provide the heat;
- further comprising a structure surrounding the heat exchanger, wherein the heat exchanger heats the structure to provide the heat;
- wherein the structure is comprised of one or more of brick, stone, ceramic, or a metal;
- wherein the heat exchanger is positioned around an exterior of the blast furnace to provide the heat;
- wherein the heat exchanger directly contacts the exterior of the blast furnace to provide the heat;
- further comprising one or more geothermally powered motors configured to use the heated heat transfer fluid to perform mechanical operations of the geothermally powered iron production subsystem, wherein the one or more geothermally powered motors are configured to perform one or more of:
- moving the iron ore through the hopper;
- rotating the crusher; and
- driving an exhaust system to remove fumes from the blast furnace;
- further comprising one or more turbines configured to use the heated heat transfer fluid to generate electricity, wherein the generated electricity provides generated electricity to power one or more motors configured to perform one or more of:
- moving the iron ore through the hopper;
- rotating the crusher; and
- driving an exhaust system to remove fumes from the blast furnace;
- wherein the blast furnace further comprises a first tap configured to remove molten pig iron from the blast furnace, and a second tap configured to remove molten slag from the blast furnace.

Embodiment 2. A method of operating a geothermally powered iron production subsystem, the method comprising:

- receiving heated heat transfer fluid from a geothermal system comprising a wellbore extending from a surface into an underground magma reservoir, the wellbore configured to heat a heat transfer fluid via heat transfer with the underground magma reservoir to form the heated heat transfer fluid;
- receiving iron ore;
- crushing the received iron ore;
- placing the crushed iron ore, limestone, and coke into a blast furnace;
- melting the crushed iron ore, limestone, and coke in the blast furnace using heat; and
- providing the heat to the blast furnace using a heat exchanger using at least in part the heated heat transfer fluid to provide the heat, wherein the method optionally includes any one or more of the following limitations:
- wherein the method further comprising:
- providing air to the heat exchanger using an air compressor system;
- heating the provided air with the heat exchanger; and
- providing the heated provided air to the blast furnace as the heat source;
- further comprising providing the heat by positioning the heat exchanger within the blast furnace;
- further comprising providing the heat by the heat exchanger heating a structure surrounding the heat exchanger;
- wherein the structure is comprised of one or more of brick, stone, ceramic, or a metal;
- further comprising providing the heat by the heat exchanger being positioned around an exterior of the blast furnace;
- further comprising providing the heat by the heat exchanger directly contacting the exterior of the blast furnace;
- further comprising powering one or more motors by geothermal power using the heated heat transfer fluid, the one or more motors configured to perform mechanical operations of the geothermally powered iron production subsystem, wherein the one or more geothermally powered motors are configured to perform one or more of:
- moving the iron ore through the hopper;
- rotating the crusher; and
- driving an exhaust system to remove fumes from the blast furnace;
- further comprising:
- generating electricity using one or more turbines powered by the heated heat transfer fluid; and
- providing the generated electricity to power one or more motors configured to perform one or more of:
- moving the iron ore through the hopper;
- rotating the crusher; and
- driving an exhaust system to remove fumes from the blast furnace.
- further comprising tapping the blast furnace to remove molten pig iron from the blast furnace, and tapping the blast furnace to remove molten slag from the blast furnace.

Although embodiments of this disclosure have been described with reference to several elements, any element described in the embodiments described herein are exemplary and can be omitted, substituted, added, combined, or rearranged as applicable to form new embodiments. A skilled person, upon reading the present specification, would recognize that such additional embodiments are effectively disclosed herein. For example, where this disclosure describes characteristics, structure, size, shape, arrangement, or composition for an element or process for making or using an element or combination of elements, the characteristics, structure, size, shape, arrangement, or composition can also be incorporated into any other element or combination of elements, or process for making or using an element or combination of elements described herein to provide additional embodiments. Moreover, items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface device, or intermediate component whether electrically, mechanically, fluidically, or otherwise.

While this disclosure has been particularly shown and described with reference to preferred or example embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Changes, substitutions and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Additionally, where an embodiment is described herein as comprising some element or group of elements, additional embodiments can consist essentially of or consist of the element or group of elements. Also, although the open-ended term “comprises” is generally used herein, additional embodiments can be formed by substituting the terms “consisting essentially of” or “consisting of.”

GEOTHERMALLY POWERED IRON PRODUCTION SYSTEMS AND METHODS

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims