UTILIZATION OF BIO-OIL OR BIOCHAR IN A BLAST FURNACE

Abstract

In various examples, the subject matter of this disclosure relates to a method and a system for reducing iron oxide to produce metallic iron. An example method includes: providing a fuel including at least one of bio-oil or fast pyrolysis biochar, feeding the fuel into a blast furnace containing iron oxide; gasifying the fuel to produce reducing gases; and reducing the iron oxide in the blast furnace using the reducing gases to produce metallic iron.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 63/674,531, filed on Jul. 23, 2024, the entire contents of which are incorporated by reference herein.

BACKGROUND

Biochar and bio-oil, also known as pyrolysis oil or biocrude, are produced through the process of pyrolysis, which involves the thermal decomposition of organic material at elevated temperatures in the absence of oxygen. The production process begins with the collection and preparation of biomass feedstock, such as wood, agricultural residues, or algae, which is dried and sometimes ground into smaller particles. This prepared biomass is then fed into a pyrolysis reactor, where it is heated to temperatures between about 400° C. and 800° C. The thermal decomposition produces a mixture of vapors, gases, and solid biochar, with the biochar being separated from the vapors. The hot vapors are cooled and condensed into liquid bio-oil, which is collected and stored. Bio-oil can be utilized as a fuel for heat and power generation or as a feedstock for producing chemicals and renewable fuels, with its characteristics varying based on the biomass type and pyrolysis conditions.

The foregoing examples of the related art and limitations therewith are intended to be illustrative and not exclusive, and are not admitted to be “prior art.” Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

SUMMARY

In various examples, the subject matter of this disclosure relates to the use of bio-oil and/or biochar in a blast furnace, where iron oxide is reduced to form metallic iron. The bio-oil can be produced in a pyrolysis process and can have a water content less than about 10%, by mass, and/or a coke replacement ratio greater than about 0.7. The biochar can be produced in a fast pyrolysis process and can have certain characteristics (e.g., higher volatile matter content) compared to other fuels (e.g., low volatile coals or slow pyrolysis biochar) that improve combustion performance. The bio-oil and biochar can be blended together and/or combined with other fuels prior to injection into the blast furnace.

In one aspect, the subject matter of this disclosure relates to a method of reducing iron oxide to produce metallic iron. The method includes: providing a fuel including at least one of bio-oil or fast pyrolysis biochar; feeding the fuel into a blast furnace containing iron oxide; gasifying the fuel to produce reducing gases; and reducing the iron oxide in the blast furnace using the reducing gases to produce metallic iron.

In another aspect, the subject matter of this disclosure relates to a system for reducing iron oxide to produce metallic iron. The system includes: a source of a fuel including at least one of bio-oil or fast pyrolysis biochar; and a blast furnace configured to: gasify the fuel to produce reducing gases; and reduce iron oxide using the reducing gases to produce metallic iron.

These and other objects, along with advantages and features of embodiments of the present invention herein disclosed, will become more apparent through reference to the following description, the figures, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings.

FIG. 1 is a schematic representation of a system for bio-oil transportation and storage, in accordance with some embodiments.

FIG. 2A is a schematic representation of a bio-oil distribution system having multiple distribution lines, in accordance with some embodiments.

FIG. 2B is a schematic representation of a bio-oil distribution system having a distribution ring system, in accordance with some embodiments.

FIG. 3 is a schematic diagram of bio-oil injection into a blast furnace tuyere via a lance, in accordance with some embodiments.

FIG. 4 is a schematic diagram of biochar injection into a blast furnace tuyere via a lance, in accordance with some embodiments.

While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The present disclosure should not be understood to be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION

Blast furnaces and basic oxygen furnaces (BOF) are integral parts of ironmaking and steelmaking processes. The primary purpose of the blast furnace is to produce molten iron (referred to as “pig iron”) from iron ore or other sources of iron oxide. The BOF converts the molten iron and scrap steel into steel by reducing the carbon content and removing impurities. On a global scale, the blast furnace to BOF route can produce around 2 tons of carbon dioxide per ton of crude steel produced. Replacing fossil-based metallurgical coke, a carbon-rich form of coal which serves as a primary fuel for blast furnaces, with biogenic fuels can substantially reduce the carbon footprint of the ironmaking process; however, securing biogenic fuels at sufficient scale, cost, and quality can be challenging. Advantageously, according to some embodiments, the methods and systems disclosed herein can produce high-quality, metallurgical grade bio-oil suitable for use in blast furnaces. Metallurgical grade bio-oil, as used herein, can refer to a bio-oil product having sufficiently low water content (e.g., less than about 10%, by mass) and/or a sufficiently high coke replacement ratio for ironmaking applications (e.g., greater than about 0.7 tonnes of coke per tonne of bio-oil injected). Additionally or alternatively, the methods and systems described herein can utilize biochar as a fuel for blast furnaces. Compared to previous approaches that utilize coal, natural gas, or other fossil-based fuels in blast furnaces, the methods and systems described herein can significantly reduce the carbon footprint of the ironmaking process, as bio-oil and biochar can be obtained from biogenic carbon sources.

Use of Bio-Oil in Blast Furnaces

Bio-oils are generally low in carbon and hydrogen content, but rich in water and oxygen. For example, the water content in bio-oil typically ranges from about 15% to about 30%, by weight, and it can vary depending on the type of biomass feedstock used and the specific pyrolysis process conditions. The high amount of water can limit the application of conventional bio-oil in blast furnace operations. Advantageously, however, the methods and systems disclosed herein can produce bio-oil having a lower water content and a higher energy content, compared to previous approaches, such that the bio-oil can be uniquely suited for blast furnace injection in ironmaking processes. In some examples, the higher energy content of the bio-oil can be achieved at least in part through deoxygenation, such that the bio-oil can have a lower oxygen content compared to conventional bio-oil. The deoxygenation can be performed using one or more catalysts, including, for example, a metal catalyst (e.g., based on platinum, nickel, cobalt, or molybdenum) or a zeolite catalyst. Additionally or alternatively, hydrogen can be used in a hydrodeoxygenation (HDO) reactor to remove oxygen from CxHyOz compounds, and in doing so can raise the fuel value of the bio-oil. Typical reactor temperatures for this process may be from 250° C. to 450° C. HDO processing can improve the favorability of bio-oil for blast furnace applications.

Further, compared to biochar or other pyrolysis products, the bio-oil produced using the methods and systems disclosed herein can be cleaner and/or have fewer contaminants. For example, the bio-oil can have as little as 5% of the contaminants present in the biomass used to produce the bio-oil. In contrast, many or most of the contaminants (e.g., including sulfur, phosphorous, potassium, and sodium) present in the biomass can end up in the biochar. The low contaminant concentrations in the bio-oil can reduce the likelihood of contaminant accumulation in the blast furnace and/or the molten iron. Advantageously, while certain biomass sources (e.g., non-woody biomass) may not be suitable to produce biochar for use in metallurgical applications, a variety of biomass sources can be used to produce a clean or contaminant-free bio-oil (e.g., with a low ash content) for such applications, as described herein. Most biomass has lower contaminant levels (e.g., sulfur and/or phosphorous) than traditional coal, such that even the produced biochar with concentrated species may carry less contaminants than the coal being substituted.

In various examples, the biomass used to produce bio-oil and biochar is or includes an organic material that is derived from living organisms such as plants. Biomass can be or include, for example, harvested plant materials, agricultural waste (e.g., corn stover), forestry residue (e.g., branches, leaves, etc.), woody biomass (e.g., trees, shrubs, bushes, etc.), non-woody biomass (e.g., sugar cane, cereal straw, seaweed, algae, cotton, grass, kelp, soil, etc.), and/or processed waste (e.g., cereal husks and cobs, bagasse, nut shells, plant oil cake, sawmill waste, papermill waste, food waste, etc.). Biomass can include fat, oil, lignin, starch, cellulose, hemicellulose, or any combination thereof.

In certain implementations, moisture in the biomass feedstock and water produced during thermal decomposition of the biomass are responsible for the presence of water in bio-oil. High water content can adversely impact the energy density and/or stability of bio-oil, and thus, bio-oil with high water content (e.g., 15% or more by mass) can be less suitable for certain applications, such as blast furnace applications. For example, high water content in bio-oil can lower a Raceway Adiabatic Flame Temperature (RAFT), which is a calculated temperature in a raceway region in front of blast furnace tuyeres where hot air is injected into the blast furnace. A RAFT value below a certain threshold value can prevent stable blast furnace operations. Thus, in some examples, maintaining a water content in bio-oil below about 10%, or about 5%, by mass, can be critical for blast furnace applications.

Advantageously, compared to previous techniques, methods of bio-oil production disclosed herein can produce a higher energy bio-oil with a lower water content and/or a lower oxygen content, which makes the resulting bio-oil uniquely suited for blast furnace injection applications, such as ironmaking. The water content of the bio-oils described herein can be, for example, from about 0% to about 4%, from about 4% to about 7%, or from about 7% to about 10%, by weight. Oxygen content of the bio-oils described herein can be less than about 30%, from about 30% to 35%, from about 35% to about 40%, from about 40% to about 45%, or from about 45% to about 50%, by weight.

The bio-oils can be produced through treatment of a bio-oil fraction obtained from a pyrolysis process, and deliberate fractionation of bio-oil at the point of production. In some embodiments, for example, bio-oil having a low water content can be obtained using a condenser configuration that condenses pyrolysis gases in multiple stages, such that water can be condensed and collected in one or more stages, and other bio-oil components can be condensed and collected in one or more other stages, similar to a distillation column. In this way, a portion of the water present in the pyrolysis gases (e.g., 25%, 50%, 75%, 90%, or more, by mass) can be separated from other bio-oil components present in the pyrolysis gases.

Additionally or alternatively, after the bio-oil has been produced using the pyrolysis process, a variety of separation techniques can be used to reduce the water content. Such techniques can include, for example, vacuum distillation, controlled phase separation, and/or filtering. In some embodiments, the bio-oil produced by the methods disclosed herein is stored in tanks near the blast furnace.

In various examples, the bio-oil used for the applications described herein can have a coke replacement ratio from about 0.7 to about 1.0, for example, from about 0.7 to about 0.8, from about 0.8 to about 0.9, or from about 0.9 to about 1.0. The coke replacement ratio, as used herein, can refer to the mass of metallurgical coke that can be substituted per unit mass of an alternative injectant, such as bio-oil. For example, a coke replacement ratio of 1.0 means that 1 ton of coke can be replaced by 1 ton of an alternative injectant. According to some embodiments, other coke replacement ratios may be used and/or may depend on requirements associated with individual blast furnace operators, such as their specific economic circumstances regarding metallurgical coke price and/or their CO₂ reduction goals.

FIG. 1 is a schematic representation of a system 100 for bio-oil transportation and storage, in accordance with certain examples. In general, bio-oil having a low water content and/or low oxygen content, as described herein, can be (i) transported 102 (e.g., by truck, train, or pipeline) from a pyrolysis facility, a dewatering facility, or a deoxygenation facility, (ii) stored 104 in a tank near a blast furnace, and (iii) delivered to a blast furnace tuyere platform 106 using a pump 108.

In referring to FIGS. 2A and 2B, bio-oil can be pumped and/or delivered to a plurality of fuel injectors positioned within tuyeres arranged around a blast furnace. The bio-oil can be distributed using, for example, a bio-oil distributor 208 and a network of distribution lines 202 (e.g., pipes or tubes) that distribute bio-oil to each tuyere 206 or fuel injector (e.g., inside the tuyere 206) from a central splitting point (as shown in FIG. 2A). Alternatively or additionally, the bio-oil may be distributed using a distributor ring or manifold 204, such as a distribution bustle, disposed around the blast furnace (as shown in FIG. 2B). Each tuyere 206 or fuel injector can be connected to the ring 204 with a pipe or line.

In some embodiments, the bio-oil in the distribution system (e.g., including the lines 202 the ring 204, and/or the fuel injectors) can be kept within an appropriate temperature range to manage bio-oil viscosity. The bio-oil temperature in the distribution system can be, for example, from about 20° C. to about 30° C., from about 30° C. to about 40° C., from about 40° C. to about 50° C., from about 50° C. to about 60° C., from about 60° C. to about 70° C., from about 70° C. to about 80° C., or from about 80° C. to about 90° C. Other bio-oil temperatures can be used.

In some embodiments, the distribution system can be pressurized to overcome higher blast pressures within the blast furnace. For example, the distribution system may be pressurized to a pressure from about 5 to about 10 psig, from about 10 to about 15 psig, from about 15 to about 20 psig, from about 20 to about 25 psig, or from about 25 to about 30 psig. Other pressures can be used.

According to some embodiments, bio-oil 302 is injected into a blast furnace tuyere 304 via lances or fuel injectors 306 as schematically shown in FIG. 3. Once the bio-oil 302 exits the lance 306 within the blast furnace tuyere 304, the bio-oil 302 can rapidly devolatilize in the presence of high temperatures and oxygen, and can form a reducing gas (e.g., including hydrogen and/or carbon monoxide) that supports reduction reactions taking place in the blast furnace (e.g., to convert iron oxide to metallic iron). Residual water present in the bio-oil 302 can support rapid atomization of the bio-oil 302, which improves conversion of the bio-oil 302 into the reducing gas within the furnace. In some examples, the bio-oil 302 can be mixed with other fuel sources, such as, for example, biochar and/or pulverized coal, and the mixture can be injected into the tuyere 304 using the fuel injector 306.

Use of Biochar in Blast Furnaces

In various examples, the biochar utilized in blast furnaces can be derived from biomass in a pyrolysis process, such as a fast pyrolysis process and/or a slow pyrolysis process. Compared to slow pyrolysis, fast pyrolysis generally involves higher heating rates and/or shorter reactor residence times. Fast pyrolysis can have a heating rate of about 1000° C./s and a reactor residence time of just a few seconds (e.g., 1, 3, 5, or 10 seconds). A temperature in the fast pyrolysis reactor can be from about 400° C. to about 600° C. By comparison, slow pyrolysis can have a heating rate less than about 10° C./min and a reactor residence time in minutes to hours (e.g., 10 minutes, 30 minutes, 1 hour, or 3 hours). A temperature in the slow pyrolysis reactor can be from about 350° C. to about 800° C. Higher temperatures can be used for slow pyrolysis but are generally more associated with gasification reactors.

In general, fast pyrolysis achieves higher yields of bio-oil and smaller yields of biochar, while slow pyrolysis achieves smaller yields of bio-oil and higher yields of biochar. Typical yields for fast pyrolysis may be, for example, from about 50% to about 70% bio-oil, from about 10% to about 30% biochar, and up to about 40% syngas, by weight. Typical yields for slow pyrolysis may be, for example, less than about 30% bio-oil, from about 25% to about 60% (e.g., 35%) biochar, and about 30% or more syngas, by weight. The biochar yield may be about 3, 4, 5, or 6 times higher with slow pyrolysis, compared to fast pyrolysis. Accordingly, entities looking to maximize bio-oil production will choose fast pyrolysis, while entities looking to maximize biochar production will choose slow pyrolysis.

In certain blast furnace applications, it can be preferable to utilize biochar that has a low ash content, for example, to reduce or minimize contamination of the molten iron. A lower ash content can be achieved, for example, by using biochar produced from woody biomass sources (e.g., oak, maple, pine, other types of wood, shrubs, or bushes).

Table 1 presents example compositions for biochar produced by fast pyrolysis and slow pyrolysis, using dry, woody biomass. Actual biochar compositions can vary depending on the biomass source and pyrolysis process conditions. In some examples, non-woody biomass can result in lower percentages of volatile matter and/or fixed carbon.

TABLE 1
Biochar compositions.
	Fast Pyrolysis	Slow Pyrolysis
Item	Biochar (FPB)	Biochar (SPB)
Carbon (wt %)	75 to 82	84 to 89
Hydrogen (wt %)	2 to 3	2 to 3
Oxygen (wt %)	13 to 20	8 to 15
Nitrogen (wt %)	0.3 to 0.9	0.3 to 0.9
Sulfur (wt %)	0.015 to 0.025	0.015 to 0.025
Hydrogen/Carbon (molar ratio)	0.5 to 0.7	0.2 to 0.4
Oxygen/Carbon (molar ratio)	0.01 to 0.25	0.01 to 0.15
Volatile Matter (%)	20 to 30	10 to 20
Fixed Carbon (%)	50 to 66	65 to 81

As Table 1 indicates, biochar produced by fast pyrolysis (referred to herein as “fast pyrolysis biochar” or “FPB”) can have a higher volatile matter (VM) content, a higher molar ratio of hydrogen to carbon, and/or a higher fixed carbon content, compared to biochar produced by slow pyrolysis (referred to herein as “slow pyrolysis biochar” or “SPB”). The higher VM content indicates FPB is generally more combustible than SPB. Here, combustibility refers to the reactivity of fuel (e.g., FPB or coal) to oxygen in the blast furnace raceway, influencing how quickly the injectant ignites, burns out, and/or gasifies (e.g., to produce hydrogen, carbon monoxide, or other reducing gases) within a limited time window in the blast furnace raceway. Biochar with higher reactivity has a higher rate of gasification or burnout (e.g., conversion of solid material to gas). Likewise, the higher molar ratio of hydrogen to carbon indicates FPB generally has a higher hydrocarbon content, compared to SPB, which can contribute to the higher combustibility of FPB. In certain implementations, FPB can have a VM content from about 20% to about 24% to about 26% to about 28% to about 30%, or higher. Additionally or alternatively, FPB can have a fixed carbon content from about 50% to about 55% to about 60% to about 66%. Additionally or alternatively, FPB can have a molar ratio of hydrogen to carbon from about 0.5 to about 0.6 to about 0.7 to about 0.8. In certain examples, FPB can have chemical and/or structure similarities with medium volatile bituminous coals, which can have about 22 to 31% volatile matter.

In various examples, fuels having a higher VM content and/or higher combustibility (e.g., due to more hydrocarbons and/or less fixed carbon) can have certain advantages in blast furnace applications. For example, such fuels can achieve better combustibility near the tuyere (e.g., at a nose of the tuyere) and higher combustion efficiency. The higher VM content can, in some instances, cause a rapid evolution of volatile matter (e.g., within about 100 milliseconds), which can be crucial for proper flame stabilization and high combustion efficiency (e.g., near the tuyere). By comparison, fuel sources having a lower VM content tend to achieve lower combustion efficiency. The combustion efficiency for low VM content fuels can depend on reactions of fixed carbon content, rather than an initial volatile matter release. Accordingly, the higher VM content and/or higher combustibility of FPB offers certain advantages over SPB in blast furnace applications.

In certain instances, FPB can be used as a fuel source in a blast furnace on its own or in combination with other fuel sources. The FPB can be mixed with solid fuel sources, such as, for example, SPB, coal (e.g., pulverized coal), or coke. Additionally or alternatively, the FPB can be mixed with bio-based liquid fuel sources, such as, for example, bio-oil (e.g., dewatered and/or de-oxygenated as described herein), glycerol, biodiesel, ethanol, other alcohols, used cooking oils, vegetable oil, plant-based oils, solutions containing microbes or algae, biocrude, or biocrude byproducts. Additionally or alternatively, the FPB can be mixed with petroleum-based liquids, such as, for example, crude oil, gasoline, kerosene, or diesel. Liquid fuel sources (e.g., a dispersion of FPB particles in bio-oil or other liquid fuel) can be pumped into the blast furnace using techniques described herein for bio-oil. Solid fuel sources (e.g., a mixture of FPB and SPB or coal) can be fed into the blast furnace in a gas carrier stream (e.g., an inert gas stream containing nitrogen).

In some examples, FPB can be combined with one or more other fuels to achieve a desired VM content, hydrocarbon content, and/or combustion characteristics. Certain fuel sources, such as SPB and low volatile bituminous coal, for example, can have a relatively low VM content and/or a relatively low combustibility. For example, low volatile bituminous coals can have about 14 to 22% volatile matter on a dry, mineral-matter-free basis, and a fixed carbon content of about 78 to 86%. SPB, with its reduced volatile content and higher fixed carbon, can have chemical and/or structural similarities with low volatile coals (e.g., low volatile bituminous coal). SPB and low volatile bituminous coal can exhibit comparable combustion behavior (e.g., poor combustion) in a blast furnace setting, where the burning of fixed carbon becomes a more critical factor for overall combustion efficiency. Advantageously, blending FPB with such fuel sources can increase VM content and improve overall combustion. The FPB can be added to SPB, low volatile coal, and/or similar fuels in an amount greater than or equal to about 10%, about 20%, about 30%, or about 40%, by weight of the mixture. The addition of FPB can increase the VM content, improve combustion, and/or maximize a decarbonization potential of the fuel in blast furnaces. In various examples, combustion performance and/or the need to add FPB (e.g., to SPB) can be more important at high rates of fuel injection, such as, for example, greater than 150, 160, 170, 180, 190, 200, or 210 kg per ton of hot metal.

In certain examples, when used in a solid fuel, FPB can be injected into a blast furnace using techniques similar to those used for pulverized coal. For example, FPB (e.g., in the form of briquettes, extrudates, or pellets) can be dosed via feed hoppers to a bin, where the FPB can be mixed with coal, SPB, and/or other solid fuel. The materials can be ground using a common coal grinding system. A mixture of FPB and other solid fuels can be stored in an intermediate tank or feed tank. Referring to FIG. 4, FPB 402 can be conveyed to the blast furnace pneumatically in an inert gas stream (e.g., a nitrogen stream), which can be divided by a distributor such that each tuyere 304 receives equal amounts. The FPB 402 and inert gas stream (plus other optional fuel sources, such as pulverized coal or SPB) can enter a hot blast of each tuyere 304 through the lance 306. This can allow the FPB 402 to access a furnace raceway where combustion occurs.

In certain examples, when used in a liquid fuel, FPB can be prepared by finely grinding the char such that it mixes well with bio-oil (or other liquid fuel source) in a fluid mixing station. The resulting mixture can be in the form of a liquid, a slurry, and/or paste. In some examples, the mixture can have from about 5% to about 10% to about 20% to about 30% to about 40% to about 50% FPB, by weight. The mixture can be pumped to the tuyere where rapid devolatilization of the bio-oil can aid in the combustion of FPB and/or bio-oil in the raceway. Oxygenated bio-oil compounds may support combustion of biochar, by providing a source of oxygen local to the combustion zone. The FPB can increase an energy content of the bio-oil.

Pyrolysis typically forms fine powders of biochar (e.g., FPB or SPB) that exhibit high porosity (e.g., about 58%) and a large surface area (e.g., about 113 m²/g). The high porosity and surface area can enhance reactivity but can impede the economics of shipping and handling. Forming biochar into extrudates or pellets can improve shipping and handling economics; however, the extrudates or pellets can have lower combustibility (e.g., due to reduced porosity and/or surface area). The higher VM content of FPB can make FPB more suitable for combustion in pelletized form, compared to SPB.

Additional Considerations

The construction and arrangement of the elements of the apparatus as shown in the exemplary embodiments is illustrative only. Although only a certain number of embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited.

Further, elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the assemblies may be reversed or otherwise varied, the length or width of the structures and/or members or connectors or other elements of the system may be varied, the nature or number of adjustment or attachment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the spirit of the present subject matter.

The features and functions of the various embodiments may be arranged in various combinations and permutations, and all are considered to be within the scope of the disclosed invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive. Furthermore, the configurations, materials, and dimensions described herein are intended as illustrative and in no way limiting. Similarly, although physical explanations have been provided for explanatory purposes, there is no intent to be bound by any particular theory or mechanism, or to limit the claims in accordance therewith.

It should be also understood that as used in the description herein the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

Each numerical value presented herein is contemplated to represent a minimum value or a maximum value in a range for a corresponding parameter. Measurements, sizes, amounts, and the like may be presented herein in a range format. The description in range format is provided merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as 1-20 meters should be considered to have specifically disclosed subranges such as 1 meter, 2 meters, 1-2 meters, less than 2 meters, 10-11 meters, 10-12 meters, 10-13 meters, 10-14 meters, 11-12 meters, 11-13 meters, etc.

The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention.

Although the concepts and principles of operation for the systems in FIGS. 1-4 have been described with limited number of components for simplicity, these systems may include additional electrical and/or mechanical components necessary for their operation. Such components may include, but are not limited to, pipes, pipe connectors, pressure regulators, different types of valves, computers, electronic controllers, transformers, power supplies, electrical control panels, etc. These additional components are within the spirit and the scope of this disclosure.

Reference in the specification to “one embodiment,” “preferred embodiment,” “an embodiment,” “some embodiments,” “embodiments,” or similar language (e.g., “examples”), means that a particular feature, structure, characteristic, or function described in connection with the embodiment can be included in at least one embodiment of the invention and may be in more than one embodiment. Also, the appearance of the above-noted phrases in various places in the specification is not necessarily referring to the same embodiment or embodiments.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Other steps or stages may be provided, or steps or stages may be eliminated, from the described processes. Accordingly, other implementations are within the scope of the following claims.

Claims

1. A method of reducing iron oxide to produce metallic iron, the method comprising:

providing a fuel comprising at least one of bio-oil or fast pyrolysis biochar;

feeding the fuel into a blast furnace containing iron oxide;

gasifying the fuel to produce reducing gases; and

reducing the iron oxide in the blast furnace using the reducing gases to produce metallic iron.

2. The method of claim 1, wherein the fuel comprises the bio-oil.

3. The method of claim 2, wherein the bio-oil comprises a water content less than about 10%, by mass.

4. The method of claim 2, wherein the bio-oil has a coke replacement ratio from about 0.7 to about 1.

5. The method of claim 1, wherein the fuel comprises the fast pyrolysis biochar.

6. The method of claim 5, wherein the fuel further comprises bio-oil.

7. The method of claim 5, wherein the fuel further comprises coal.

8. The method of claim 5, wherein the fuel further comprises slow pyrolysis biochar.

9. A system for reducing iron oxide to produce metallic iron, the system comprising:

a source of a fuel comprising at least one of bio-oil or fast pyrolysis biochar; and

a blast furnace configured to: gasify the fuel to produce reducing gases; and reduce iron oxide using the reducing gases to produce metallic iron.

10. The system of claim 9, wherein the fuel comprises the bio-oil.

11. The system of claim 10, wherein the bio-oil has at least one of a water content less than about 10%, by mass, or a coke replacement ratio from about 0.7 to about 1.

12. The system of claim 9, wherein the fuel comprises the fast pyrolysis biochar.

13. The system of claim 12, wherein the fuel further comprises bio-oil.

14. The system of claim 12, wherein the fuel further comprises at least one of coal or slow pyrolysis biochar.

15. The system of claim 12, wherein the fuel comprises a liquid, a slurry, or a paste.

16. The system of claim 9, wherein the system further comprises a plurality of lines configured to feed the fuel to a plurality of tuyeres in the blast furnace.

17. The system of claim 9, wherein the system further comprises a ring-shaped manifold disposed around the blast furnace and configured to feed the fuel to a plurality of tuyeres in the blast furnace.