Process for producing hydrogen and graphitic carbon from hydrocarbons

Abstract

To provide a process for producing hydrogen and graphitic carbon from a hydrocarbon gas.SOLUTION: There is provided a process comprising contacting, at a temperature between 600°C and 1000°C, a catalyst with a hydrocarbon gas to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphitic carbon, wherein the catalyst is a low grade iron oxide. Also there is provided a method for the beneficiation of catalytic metal containing ore, the method comprising contacting, at a temperature between 600°C and 1000°C, the catalytic metal containing ore with a hydrocarbon gas to form a carbon-coated metal species.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a process for producing hydrogen and graphite-like carbon. [Background technology]

[0002] Hydrogen has many commercial applications, including as a clean and environmentally friendly alternative to fuel for internal combustion engines. Carbon, more specifically graphite, is considered a key material in the emerging green technology market and has been shown to be useful in energy storage, electrical conduction devices, catalyst supports, lubricating additives, and modern electronic devices. All references to carbon in this patent refer to the graphitic form of carbon, and these terms are used interchangeably throughout.

[0003] However, conventional methods of producing hydrogen from fossil fuels generate carbon dioxide, which is harmful to the environment (natural gas steam reforming and coal gasification).

[0004] Natural gas can be catalytically decomposed into hydrogen gas and solid carbon according to formula (1). CH4 → C + 2H2(1)

[0005] In this process, carbon is deposited on the catalyst surface and hydrogen gas is released. Numerous known catalysts exist for this process, including those made from precious metals and carbon.

[0006] Although the process described above is publicly known, it has not been commercially utilized for numerous economic reasons. This is primarily related to the cost of the underlying catalyst, both during initial supply and during recycling / regeneration. Most researchers in this field have used expensive complex-supported catalysts that, despite high catalytic activity and product yield, have very high catalyst turnover costs. Such costs represent a significant barrier to commercializing the use of these catalysts. There is a keen need for new and improved processes and catalysts for catalytically converting hydrocarbons into stable and commercially valuable hydrogen and solid carbon.

[0007] The above discussion in the background art is intended solely to facilitate understanding of the present invention. It should be understood that the above discussion does not confirm or acknowledge that any of the material mentioned was part of common knowledge in Australia on the priority date of this application. [Overview of the project] [Problems that the invention aims to solve]

[0008] In its broadest sense, the present invention provides a process for producing hydrogen and graphitic carbon from hydrocarbon gases. In particular, the present invention provides a process for catalytically converting hydrocarbon gases to hydrogen and graphitic carbon using a low-grade catalyst.

[0009] Throughout this specification, the term “low grade” will be understood to mean materials that are not synthesized, unless the context requires otherwise. As will be understood by those skilled in the art, synthetic materials are produced by the chemical reaction of precursor materials. A standard synthesis technique for catalysts excluded from this invention is, for example, impregnating an inert support with nano-sized catalyst elements. The term “low grade” includes natural materials, but should not be understood to exclude materials that have undergone physical beneficiation such as crushing and screening or classification.

[0010] Throughout this specification, unless otherwise specified, all pressures are given in bar (measurement unit), where 0 bar is atmospheric pressure. [Means for solving the problem]

[0011] The present invention provides a process for producing hydrogen and graphitic carbon from a hydrocarbon gas, comprising contacting a catalyst with the hydrocarbon gas at a temperature between 600°C and 1,000°C to catalytically convert at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon, wherein the catalyst is low-grade iron oxide.

[0012] Preferably, the pressure is higher than atmospheric pressure.

[0013] In one embodiment of the present invention, the step of catalytically converting at least a portion of a hydrocarbon gas into hydrogen and graphitic carbon by contacting a catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C more specifically includes the steps of reducing at least a portion of iron oxide to iron, decomposing the hydrocarbon gas to produce hydrogen gas and an iron carbide intermediate, and precipitating graphitic carbon on the surface of the iron.

[0014] In one embodiment of the present invention, the step of contacting the catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 100 bar. Preferably, the step of contacting the catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 50 bar. More preferably, the step of contacting the catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 20 bar. Even more preferably, the step of contacting the catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 2 bar to 10 bar.

[0015] In one embodiment of the present invention, the step of catalytically converting at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon by contacting a catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is preferably carried out at a temperature between 700°C and 950°C.

[0016] In a second embodiment of the present invention, the step of catalytically converting at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon by contacting the catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C is preferably carried out at a temperature between 800°C and 900°C.

[0017] In a third aspect of the present invention, the step of contacting the catalyst with the hydrocarbon gas at a temperature between 600 °C and 1,000 °C to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphite-like carbon is preferably carried out at a temperature from 650 °C to 750 °C.

[0018] The inventors have discovered that the method of the present invention enables the use of low-grade catalysts while achieving high conversion rates and yields.

[0019] Without wishing to be bound by theory, the inventors understand that the advantage of using iron ore is that the metal species catalyze the decomposition reaction and the catalytic elements are exposed to the hydrocarbon gas according to the mineralogy of the ore. The applicant understands that the force for the deposition of the graphite layer on the surface of the catalyst component is sufficient to break and peel off the covering catalyst particles from the catalyst and further expose the iron oxide of the catalyst. Therefore, the catalyst is self-supporting and does not require extensive preparation before use.

[0020] In one aspect of the present invention, the hydrocarbon gas is methane. Preferably, the hydrocarbon gas is natural gas.

[0021] In one aspect of the present invention, the catalyst is ground to a particle size of less than 20 mm. Preferably, the catalyst is ground to a particle size of less than 15 mm. More preferably, the catalyst is ground to a particle size of less than 10 mm. Even more preferably, the catalyst is ground to a particle size of less than 5 mm. Even more preferably, the catalyst is ground to a particle size of less than 1 mm. Even more preferably, the catalyst is ground to a particle size of less than 0.5 mm. Even more preferably, the catalyst is ground to a particle size of less than 0.1 mm.

[0022] In one aspect of the present invention, the step of contacting the catalyst with the hydrocarbon gas at a temperature between 600 °C and 1,000 °C is carried out in a pressure reactor. Preferably, the pressure reactor is selected from the group consisting of a fixed-bed reactor, a moving-bed reactor, and a fluidized-bed reactor.

[0023] In one embodiment of the present invention, the catalyst is disposed on a substantially horizontal surface of the reactor and is exposed to a cross-flow of hydrocarbon gas. In a second embodiment of the present invention, the catalyst is suspended within a fluidized bed reactor and hydrocarbon gas is flowed through the fluidized bed.

[0024] In one embodiment of the present invention, the step of contacting the catalyst with the hydrocarbon gas is carried out in a plurality of pressurized reactors arranged in series.

[0025] In one embodiment of the present invention, the series arrangement of the reactors enables the gas to flow from the first reactor to subsequent reactors. Preferably, each subsequent reactor in the series operates at a lower pressure than the preceding reactor so that the gas can move to the reactor at a lower pressure. In the series arrangement, if there is unreacted hydrocarbon gas, it moves to a subsequent reactor at a lower pressure, contacts additional catalyst and is further processed, and the hydrocarbon gas is more completely converted to hydrogen and graphitic carbon.

[0026] In another embodiment of the present invention, the series arrangement of the reactors enables the catalyst to flow from the first reactor to subsequent reactors. Preferably, each subsequent reactor in the series operates at a higher pressure than the preceding reactor so that the catalyst can move to the reactor at a higher pressure. At low pressures, some portions of the catalyst may only be partially deactivated. In the series arrangement, the partially deactivated catalyst moves to a subsequent reactor at a higher pressure, contacts additional hydrocarbon gas and is further processed to produce graphitic carbon of higher purity. The applicant contemplates providing subsequent reactors below the preceding reactors so that the flow of catalyst between the reactors is assisted by gravity. The applicant has named this a cascade arrangement.

[0027] In one embodiment of the present invention, two pressurized reactors are used in series. The first reactor is at a pressure between 15 bar and 25 bar. The second reactor is at a pressure between 0 bar and 1 bar.

[0028] In another embodiment of the present invention, three pressurized reactors are used in series. When three pressurized reactors are used in series, The first reactor is at a pressure between 15 bar and 25 bar. The second reactor is at a pressure between 5 bar and 10 bar. The third reactor is at a pressure between 0 bar and 1 bar.

[0029] In another embodiment of the present invention, four pressurized reactors are used in series. When four pressurized reactors are used in series, The first reactor is at a pressure between 20 and 30 bar. The second reactor is at a pressure between 5 bar and 15 bar. The third reactor is at a pressure between 4 bar and 6 bar. The fourth reactor is at a pressure between 0 bar and 1 bar.

[0030] In another embodiment of the present invention, five pressurized reactors are used in series. When five pressurized reactors are used in series, The first reactor is at a pressure between 25 bar and 35 bar. The second reactor is at a pressure between 10 bar and 20 bar. The third reactor is at a pressure between 5 bar and 10 bar. The fourth reactor is at a pressure between 4 bar and 6 bar. The fifth reactor is at a pressure between 0 bar and 1 bar.

[0031] The viability and economic motivations for converting hydrocarbon gases to hydrogen and graphitic carbon are the competing dynamic and thermodynamic motivations of the reaction. As discussed earlier, the decomposition of hydrocarbon gases ultimately leads to the precipitation of graphitic carbon on the surface of the catalyst's metal particles. Precipitation continues until methane can no longer penetrate the overlying graphite to reach the catalyst. Dynamically, increasing the reaction pressure is a motivation for the reaction because it allows for better diffusion of methane into the graphitic structure covering the active catalyst surface, leading to higher catalyst utilization. Higher catalyst utilization also leads to higher purity of the graphitic product. A competing factor is that the thermodynamics of the reaction emphasize starting the reaction at lower pressures. Higher pressures increase the amount of product gas (2 moles of hydrogen are produced per mole of methane supplied), leading to an equilibrium position that is more favorable to the initial reagent than to the product. This equilibrium position limits the percentage of methane supplied that can be converted to hydrogen. This is known in this field as the thermodynamic equilibrium limit (TEL), which decreases as the reaction pressure increases.

[0032] The inventors have discovered that by arranging multiple reactors in series, the competing dynamic and thermodynamic driving forces of the reaction can be controlled by changing the pressure in each subsequent reactor. This not only allows for higher catalytic activity at higher pressures, but also increases the conversion of hydrocarbon gas supply at lower pressure reactors. The advantage of using multiple reactors in series is that it becomes possible to utilize increased reaction pressure to increase the product yield per unit area (catalytic utilization) of the catalyst used while maintaining high methane conversion efficiency (TEL).

[0033] In one embodiment of the present invention, which uses multiple reactors in series to enable gas flow between reactors, an unreacted catalyst is provided in each reactor. In this configuration, the unreacted catalyst is packed into each reactor before contact with the hydrocarbon gas. A portion of the hydrocarbon gas is converted to hydrogen and graphitic carbon in the reactor with the highest pressure. The first reactor has an associated TEL, resulting in an under-conversion of the hydrocarbon gas to hydrogen and carbon. The resulting hydrocarbon gas / hydrogen mixture moves to one or more subsequent reactors with lower pressure. The lower the pressure of the reactor, the higher the associated TEL, allowing for further conversion of the hydrocarbon gas to hydrogen and carbon. When an unreacted catalyst is provided in each reactor, the applicant has named this configuration a parallel gas multiple pressure reactor (parallel gas MPR).

[0034] In a second embodiment of the present invention, which uses multiple reactors in series to enable catalyst flow between reactors, each reactor is supplied with unreacted hydrocarbon gas. In this configuration, the hydrocarbon gas flows continuously through the reactors. When the unreacted catalyst is supplied to the reactor with the lowest pressure, methane is catalytically converted, and a partially deactivated catalyst is produced. The partially deactivated catalyst moves to the next reactor in the series with higher pressure, further catalytically converting methane. The increasing pressure in the reactors allows for further deactivation of the catalyst. The movement of the partially deactivated catalyst is repeated along the multiple reactors with increasing pressure. When the unreacted hydrocarbon gas is supplied to each reactor, the applicant has named this configuration a parallel catalyst multiple pressure reactor (parallel catalyst MPR).

[0035] In a third embodiment of the present invention, multiple reactors are arranged in series to allow both hydrocarbon gas and catalyst to flow in opposite directions between reactors. In this configuration, unreacted catalyst is supplied to the reactor with the lowest pressure, and unreacted hydrocarbon gas is supplied to the reactor with the highest pressure. The catalyst moves between pressure chambers in a counterflow relative to the gas flow between chambers, towards the higher pressure. The applicant has named this configuration a counterflow multiple pressure reactor (counterflow MPR). The partially inactivated catalyst maintains its activity in the reactors with higher pressures, resulting in higher purity (percentage by mass (%)) of the resulting graphite product, and correspondingly higher value.

[0036] The inventors have found that a counterflow MPR configuration allows for more complete conversion of hydrocarbon gases and higher purity of graphitic carbon products. Since there is no catalyst flow in parallel gas MPR, or no gas flow in parallel catalyst MPR, the design is much simpler compared to counterflow MPR.

[0037] In one embodiment of the present invention, the process is configured to preferentially produce either higher purity hydrogen or graphitic carbon. As will be understood by those skilled in the art, both hydrogen and graphitic carbon products are usually produced in a constant ratio of 1:3 by mass (carbon:graphitic carbon), as determined by the basic reaction stoichiometry. Nevertheless, the purity of one product can be increased to a higher degree than the other.

[0038] In one embodiment of the present invention, where the process is adjusted to preferentially produce higher purity hydrogen, the process includes contacting a catalyst with a hydrocarbon gas at a temperature between 800°C and 900°C and under atmospheric pressure to catalytically convert at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon.

[0039] Preferably, the process is carried out in a single fluidized bed reactor.

[0040] If higher purity hydrogen is desired, the conditions for increasing methane conversion efficiency are strengthened. Increasing hydrogen purity in a single-stage reactor typically involves lowering the pressure and increasing the temperature, which, according to thermodynamics, maximizes the conversion. However, increasing the conversion further comes at the cost of increased catalyst consumption, resulting in a decrease in graphite purity as a result of a lower catalyst yield per unit area.

[0041] In one embodiment of the present invention, in which the process is adjusted to preferentially produce higher purity graphitic carbon, the process includes contacting a catalyst with a hydrocarbon gas at a temperature between 650°C and 950°C and a pressure between 2 bar and 100 bar to catalytically convert at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon.

[0042] Preferably, the process is carried out in a fluidized bed reactor.

[0043] If higher purity graphitic carbon is desired, the conditions for enhancing catalytic utilization are strengthened. Graphite quality is a function of purity with respect to non-carbon content and crystallinity. Increasing the purity of graphitic carbon in a single-stage reactor typically involves broadening the temperature range and increasing the pressure, which maximizes catalytic utilization.

[0044] A further aspect of the present invention is provided, a method for beneficiating a catalyst metal containing ore, comprising contacting the catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C to form a carbon-coated metal species.

[0045] Preferably, the pressure is higher than atmospheric pressure.

[0046] In one embodiment of the present invention, the carbon-coated metal species is a graphite-coated metal species.

[0047] In one embodiment of the present invention, the step of forming a carbon-coated metal species by contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C is more specifically, A step of reducing at least a portion of the catalyst metal containing ore to a catalyst metal species, A process of decomposing hydrocarbon gas to produce hydrogen gas and a catalyst metal carbide intermediate, A process of precipitating graphite-like carbon on the surface of the catalyst metal. Includes.

[0048] Without being constrained by theory, the applicant understands that the force of the graphite layer precipitation on the surface of the catalyst components is sufficient to break and detach the overlying catalyst particles from the remaining ore deposits. Once the overlying catalyst particles are broken, further catalyst components within the ore are exposed to hydrocarbon gas.

[0049] In one embodiment of the present invention, the catalyst metal containing the ore is iron ore.

[0050] As discussed earlier, the metallic species in iron ore act as catalysts for decomposition reactions. Most of the iron in the Earth's crust exists in a form called banded iron formations (BIF), which consist of layers of iron separated by layers of non-ferrous minerals, typically SiO2. The advantage of this configuration is that the iron layers are never completely trapped by the non-ferrous species, so the gas always has access to the iron layers. Furthermore, the iron concentration in iron ore is relatively high. In contrast, catalytic elements in other ores are often trapped by non-catalytic species because their concentrations are very low and they are not layered, preventing process gases from coming into contact with the catalytic elements and reacting.

[0051] In one embodiment of the present invention, the process is carried out in a pressurized dusting reactor. Preferably, in the pressurized dusting reactor, a catalyst metal containing ore is brought into contact with a hydrocarbon gas to produce nano / micron-sized graphite-coated metal particles. The advantage is that larger (greater than 1 mm) non-catalytic gangue species remain unchanged. This size difference allows the graphite-coated metal species to be separated and extracted from the gangue using physical separation techniques.

[0052] In one embodiment of the present invention, the dusting reactor is a fluidized bed reactor. The inventors have found that an advantage of using a fluidized bed reactor is that nano / micron-sized graphite-coated metal particles are simultaneously separated from larger gangue species during the beneficiation process. The smaller graphite-coated metal particles are carried by the process gas flow and removed from the reactor by this gas flow, while the larger gangue particles remain in the reactor. In one embodiment of the present invention, the smaller graphite-coated metal species are removed from the gas flow by a gas-solid separator capable of settling the particles. The gangue can be continuously removed from the dusting reactor by periodic discharge by gravity.

[0053] In one embodiment of the present invention, the step of contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C to form a carbon-coated metal species is preferably carried out at a temperature between 700°C and 950°C.

[0054] In one embodiment of the present invention, the step of contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C to form a carbon-coated metal species is preferably carried out at a temperature between 800°C and 900°C.

[0055] In one embodiment of the present invention, the step of contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C to form a carbon-coated metal species is preferably carried out at a temperature between 650°C and 750°C.

[0056] In one embodiment of the present invention, the step of forming a carbon-coated metal species by contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 100 bar.

[0057] In one embodiment of the present invention, the step of forming a carbon-coated metal species by contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 50 bar.

[0058] In one embodiment of the present invention, the step of forming a carbon-coated metal species by contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 bar to 20 bar.

[0059] In one embodiment of the present invention, the step of forming a carbon-coated metal species by contacting a catalyst metal containing ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C is carried out at a pressure of 0 to 10 bar.

[0060] In one embodiment of the present invention, graphite is extracted from a graphite-coated metal species by contacting the species with hydrogen gas at a temperature of 700°C to 900°C. Preferably, the step of contacting the graphite-coated metal species with hydrogen gas at a temperature of 700°C to 900°C is carried out in a pressurized reduction reactor.

[0061] In one embodiment of the present invention, the extraction of graphite from the graphite-coated metal species is carried out in a pressurized reduction reactor at a pressure of 0 to 100 bar. The inventors understand that higher pressures are more favorable for the extraction of graphite. In a preferred embodiment of the present invention, the extraction of graphite from the graphite-coated metal species is carried out in a pressurized reduction reactor at a pressure of 10 to 20 bar.

[0062] The process of contacting a graphite-coated metal species with hydrogen gas at a temperature of 700°C to 900°C produces methane. In one embodiment of the present invention, the methane is recycled to produce hydrogen. More specifically, the process of recycling methane includes contacting a low-grade iron ore catalyst with methane at a temperature between 600°C and 1,000°C to catalytically convert at least a portion of the methane into hydrogen and graphitic carbon.

[0063] In one embodiment of the present invention, hydrogen produced in a methane recycling process is used in a process in which graphite-coated metal species are brought into contact with hydrogen gas at a temperature of 700°C to 900°C to extract graphite from the graphite-coated metal species.

[0064] When iron ore is beneficiated, if graphite is extracted in the reduction reaction, the metal species often remains in a highly pure form, as metal iron. [Brief explanation of the drawing]

[0065] Further features of the present invention are described more fully in the following description of some non-limiting embodiments of the invention. This description is included solely for illustrative purposes and should not be construed as a limitation to the broad summary, disclosure, or description of the invention above. The description is made with reference to the accompanying drawings. [Figure 1] Figure 1 shows a schematic diagram of the process for generating hydrogen and graphite according to the counterflow MPR of the present invention. [Figure 2] Figure 2 shows a schematic diagram of the process for producing hydrogen and graphite according to the parallel gas MPR of the present invention. [Figure 3] Figure 3 shows a schematic diagram of the process for producing hydrogen and graphite according to the parallel catalyst MPR of the present invention. [Figure 4] Figure 4 shows a schematic diagram of the process for beneficiating a catalyst metal containing ore according to the first embodiment. [Figure 5] Figure 5 is a graph of the XRD plots of analytical grade iron oxide and iron ore catalyst samples. [Figure 6] Figure 6 is a graph showing the carbon purity (weight %) and carbon yield (grams of carbon per gram of iron - GC / GFe) of the iron oxide catalyst after the reaction. [Figure 7] Figure 7 is a schematic diagram of a three-stage cascade counterflow system. [Figure 8A] Figure 8A shows a schematic diagram of the experimental conditions used to test methane conversion in an MPR system having three series reactors using a stationary fixed-bed reactor. [Figure 8B]Figure 8B shows a schematic diagram of the experimental conditions used to test methane conversion in an MPR system with three series reactors using a stationary fixed-bed reactor. [Figure 9] Figure 9 is a graph showing the results of methane conversion using a hematite catalyst at different reaction pressures. [Figure 10] Figure 10 is a graph showing the carbon purity (important %) and carbon yield (grams of carbon per gram of iron - GC / GFe) of the hematite catalyst at different reaction pressures. [Figure 11] Figure 11 shows a schematic diagram of the variables used for calculating the mass balance of a counterflow MPR system. [Figure 12] Figure 12 is a graph showing the mass balance calculation results for both counterflow MPR and parallel MPR, representing the catalyst mass flow rate required for an equilibrium system with a hydrogen production rate of 2,000 m3 / hr. [Modes for carrying out the invention]

[0066] Those skilled in the art will understand that the inventions described herein are subject to modifications and alterations other than those described in detail. The inventions include all such modifications and alterations. Furthermore, the inventions include all the steps, features, formulations, and compounds mentioned or indicated in the specification, individually or collectively, in any combination, or as any two or more steps or features.

[0067] Every document, reference, patent application, or patent cited herein is expressly incorporated herein by reference. This means that they should be read and considered by the reader as part of the text. The documents, references, patent applications, or patents cited herein are not repeated in the text solely for the sake of brevity. However, neither the cited material nor the information contained herein should be taken as common general knowledge.

[0068] Manufacturer's manuals, instructions, product specifications, and product sheets for any product mentioned in this specification or any documents incorporated herein by reference are incorporated herein by reference and may be used in the practice of the invention.

[0069] The present invention is not limited in scope by any of the specific embodiments described herein. These embodiments are for illustrative purposes only. Functionally equivalent products, formulations, and methods are clearly included within the scope of the invention as described herein.

[0070] The inventions described herein may include one or more ranged values ​​(e.g., size, concentration, etc.). A ranged value is understood to include all values ​​within the range, including the value defining the range and values ​​adjacent to the range and defining the range boundary that produce the same or substantially the same result as the nearest value.

[0071] Throughout the specification, unless the context requires otherwise, the term “comprise,” or variations such as “comprises” or “comprising,” shall be understood to mean that they include the integer or group of integers mentioned, but do not exclude any other integer or group of integers.

[0072] Any further definitions of the selected terms used herein are found in the detailed description of the invention, and those definitions apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains.

[0073] The features of the invention are described with reference to the following non-limiting description and examples.

[0074] In its general form, the invention relates to a process for producing hydrogen and graphitic carbon from hydrocarbon gases. In particular, the invention provides a process for catalytically converting hydrocarbon gases to hydrogen and graphitic carbon using a low-grade iron oxide-containing catalyst.

[0075] Hydrocarbon gases can be any gaseous stream containing light hydrocarbons. Exemplary examples of hydrocarbon gases include, but are not limited to, natural gas, coalbed gas, landfill gas, and biogas. The composition of hydrocarbon gases is broad, but generally includes one or more light hydrocarbons in the group including methane, ethane, ethylene, propane, and butane.

[0076] In a preferred embodiment of the present invention, the hydrocarbon gas is natural gas.

[0077] The process for producing hydrogen and graphitic carbon from natural gas involves contacting a catalyst with a hydrocarbon gas at a temperature between 600°C and 1,000°C to catalytically convert at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon, wherein the catalyst is low-grade iron oxide.

[0078] Referring to Figure 1, a counterflow MPR process 10 using three fluidized bed reactors is described, which produces hydrogen 12 and graphitic carbon 14 from a hydrocarbon gas, such as natural gas 16.

[0079] In the embodiment shown in Figure 1, the process uses three reactors operating at different pressures: a high-pressure reactor 18 below 18 bar, a medium-pressure reactor 20 below 6 bar, and a low-pressure reactor 22 below 1 bar. The reactor temperatures are 850°C each. Reactors 18, 20, and 22 are arranged in series to transfer hydrogen and unreacted hydrocarbon natural gas between adjacent reactors, for example, from the high-pressure reactor 18 to the medium-pressure reactor 20, and from the medium-pressure reactor 20 to the low-pressure reactor 22.

[0080] Each reactor 22, 20, and 18 is packed with low-grade iron oxide catalysts, such as iron ore 24”, 24', and 24, respectively. 24 is the unused, unreacted catalyst, while 24' and 24”, are progressively used, with more graphitic carbon deposits and less overall catalytic activity remaining. Stream 14 contains only trace amounts of completely exhausted catalyst, and the majority of this stream (over 90% by weight at a reaction temperature of 850°C) is graphitic carbon.

[0081] The amount of catalyst required for this reaction depends on the amount of hydrogen required, the process conditions, and the type of catalyst. A 2,000 m³ reactor operating under the above conditions in three reactors... 3 A hydrogen generation plant requires approximately 14 kg / hr of iron.

[0082] Natural gas 16 is passed through a series of reactors, from a high-pressure reactor 18 to a medium-pressure reactor 20 and a low-pressure reactor 22. Each reactor converts a portion of the natural gas into hydrogen, so that the subsequent gas streams 28, 30, and 12 contain more hydrogen. The unused natural gas 16 is first brought into contact with the catalyst 24" in the high-pressure reactor 18 at a temperature of 850°C and a pressure of 18 bar, where a portion of the natural gas is converted into hydrogen, so the corresponding gas stream 28 is a mixture containing hydrogen and unreacted natural gas. This reactor also deposits some graphitic carbon on the catalyst 24" which contributes to the total amount of graphitic carbon in stream 14.

[0083] The gas stream 28 moves to the medium-pressure reactor 20, where it comes into contact with the catalyst 24' at a temperature of 850°C and a pressure of 6 bar, where the natural gas is converted into hydrogen and carbon. The lower pressure in the medium-pressure reactor 20 allows for the conversion of the gas stream 28, contributing to the total amount of hydrogen 12. The process deposits graphitic carbon on the catalyst 24', contributing to the total amount of graphitic carbon 14. Some of the natural gas in the gas stream 28 remains unreacted and mixes with the generated hydrogen gas to form the gas stream 30.

[0084] The gas stream 30 moves to the low-pressure reactor 22, where it comes into contact with the catalyst 24 at a temperature of 850°C and a pressure of 1 bar (atmospheric pressure). The lower pressure in the low-pressure reactor 22 allows the thermodynamic equilibrium of the reaction to be more favorable to the decomposition direction of the reaction, enabling further conversion of the second gas stream 30 into carbon and hydrogen gas. The process deposits graphitic carbon on the catalyst 24, contributing to the total graphitic carbon stream 14. This reactor also contributes hydrogen gas to the total hydrogen stream 12, which exits the reactor for use or further processing.

[0085] Theoretical and empirical calculations determine that reactors 18, 20, and 22 have conversion efficiencies of 54%, 75%, and 94%, respectively, and correspondingly, gas streams 28, 30, and 12 have hydrogen concentrations of 70% by weight, 86% by weight, and 97% by weight, respectively.

[0086] The proportions of graphitic carbon in iron oxide streams 24, 24', 24'', and 14 are 0%, 91%, 95%, and 98%, respectively.

[0087] In the embodiment shown in Figure 1, when natural gas 16 comes into contact with catalyst 24 at high temperature to produce hydrogen gas 12 and carbon 14, catalyst 24 is consumed to form a partially inactivated catalyst 24'. The partially inactivated catalyst 24' moves between reactors as a counterflow to the natural gas 16 stream. Catalyst 24 is introduced into reactor 22, which has the lowest pressure, and then passed to reactors with higher pressures. Thus, the partially inactivated catalyst 24' retains its activity in reactor 20, which has a higher pressure, and the resulting graphitic carbon 14 has a higher carbon purity (as a percentage by mass (%)) and, correspondingly, a higher value.

[0088] Figure 2 shows the parallel gas MPR process 50. The parallel gas MPR process 50 shares common features with the counterflow MPR process 10, and the same reference numbers indicate the same parts.

[0089] In the embodiment shown in Figure 2, the process uses three reactors operating at different pressures: a high-pressure reactor 18 below 18 bar, a medium-pressure reactor 20 below 6 bar, and a low-pressure reactor 22 below 1 bar. The reactor temperatures are 850°C each. Reactors 18, 20, and 22 are arranged in series, allowing unreacted hydrocarbon natural gas to be moved between adjacent reactors, for example, from the high-pressure reactor 18 to the medium-pressure reactor 20, and from the medium-pressure reactor 20 to the low-pressure reactor 22.

[0090] Each reactor 18, 20, and 22 is filled with iron ore catalyst 52. In contrast to the counterflow MPR process 10 described earlier, each reactor 22, 20, and 18 is supplied with unreacted catalyst 52 before contact with hydrocarbon gas.

[0091] The amount of catalyst required for this reaction depends on the amount of hydrogen required, the process conditions, and the type of catalyst. A 2,000 m³ reactor operating under the above conditions using three reactors... 3 A hydrogen production plant requires approximately 27 kg / hr of iron.

[0092] Natural gas 16 is passed through a series of reactors, from a high-pressure reactor 18 to a medium-pressure reactor 20 and a low-pressure reactor 22. Each reactor converts a portion of the natural gas into hydrogen, so that the subsequent gas streams 28, 30, and 12 contain more hydrogen. The unreacted natural gas 16 first comes into contact with catalyst 34 in the high-pressure reactor 18 at a temperature of 850°C and a pressure of 18 bar, where a portion of the natural gas is converted into hydrogen, producing gas stream 28, which is a mixture of hydrogen and unreacted natural gas. Graphite also deposits on catalyst 34, producing a partially graphite stream 54.

[0093] The gas stream 28 passes to the medium-pressure reactor 20, where it comes into contact with the catalyst 52 at a temperature of 850°C and a pressure of 6 bar, where the natural gas is converted into hydrogen and carbon. The lower pressure in the medium-pressure reactor 20 allows for further conversion of the gas stream 28, contributing to the total hydrogen stream 12. The process deposits carbon onto the catalyst 52, producing a partial graphite stream 56. Some of the natural gas in the gas stream 28 remains unreacted and mixes with the generated hydrogen gas to form the gas stream 30.

[0094] The gas stream 30 passes to the low-pressure reactor 22, where it comes into contact with the catalyst 52 at a temperature of 850°C and a pressure of 1 bar (atmospheric pressure). The lower pressure in the low-pressure reactor 22 allows the thermodynamic equilibrium of the reaction to be more favorable to the decomposition direction of the reaction, enabling the conversion of natural gas in the second gas stream 30 into carbon and hydrogen gas. The process deposits carbon on the catalyst 52, producing a partial graphite stream 58. This reactor also contributes to the hydrogen gas in the total hydrogen stream 12, and the hydrogen gas exits the reactor for use or further processing.

[0095] Partial graphite flows 54, 56, and 58 contain a mixture of unreacted iron ore and graphitic material. Given the different pressures in reactors 22, 20, and 18, each partial graphite flow has a different conversion rate. Partial graphite flow 58 has the highest amount of iron impurities, followed by partial graphite flows 56 and 54.

[0096] In the experiment, reactors 18, 20, and 22 had conversion efficiencies of 54%, 75%, and 94%, respectively, and correspondingly, gas streams 28, 30, and 12 had hydrogen concentrations of 70% by weight, 86% by weight, and 97% by weight, respectively.

[0097] Figure 3 shows the parallel catalyst MPR process 60. The parallel MPR process 60 shares common features with the counterflow MPR process 10, and the same reference numerals indicate the same parts.

[0098] In the embodiment shown in Figure 3, the process uses three reactors operating at different pressures: a high-pressure reactor 18 below 18 bar, a medium-pressure reactor 20 below 6 bar, and a low-pressure reactor 22 below 1 bar. The temperature of each reactor is 850°C.

[0099] Each reactor 18, 20, and 22 is filled with low-grade iron oxide containing catalyst, such as iron ore 24”, 24', and 24, respectively. 24 is the unreacted catalyst, while 24' and 24'' are progressively used, with more carbon deposits and less overall catalytic activity remaining. Stream 14 contains only trace amounts of completely depleted catalyst, and the majority of this stream (over 90% by weight at a reaction temperature of 850°C) is graphite.

[0100] Reactors 18, 20, and 22 are arranged in series to move catalysts 24'', 24', and 24 between adjacent reactors, for example, from the low-pressure reactor 22 to the medium-pressure reactor 20, and from the medium-pressure reactor 20 to the high-pressure reactor 18.

[0101] In contrast to the counterflow MPR process 10 described above, unreacted natural gas 16 is supplied to each of the reactors 22, 20, and 18.

[0102] In the embodiment shown in Figure 3, when natural gas 16 comes into contact with catalyst 24 at a high temperature to produce hydrogen gas 12 and carbon 14, catalyst 24 is consumed to form a partially inactivated catalyst 24'. The partially inactivated catalysts 24' and 24'' move between reactors. Catalyst 24 is introduced into reactor 22, which has the lowest pressure, and then passed to reactors 20 and 18, which have higher pressures. Thus, the partially inactivated catalyst 24' retains its activity in reactor 20, which has a higher pressure, and the resulting carbon 14 has a higher carbon purity (as a percentage by mass (%)) and, correspondingly, a higher value.

[0103] Natural gas 16 is brought into contact with catalyst 24 in a low-pressure reactor 22 at a temperature of 850°C and a pressure of 18 bar, where a portion of the natural gas 16 is converted to hydrogen, producing a gas flow 68 which is a mixture containing hydrogen and unreacted natural gas. Graphite carbon deposits on catalyst 24, producing catalyst 24' which contributes to the total carbon in the flow 14.

[0104] Natural gas 16 is brought into contact with catalyst 24' in a medium-pressure reactor 20 at a temperature of 850°C and a pressure of 6 bar, where the natural gas 16 is converted to hydrogen, producing a gas flow 64 which is a mixture containing hydrogen and unreacted natural gas. Graphite carbon deposits on catalyst 24', producing catalyst 24'' which contributes to the total carbon in the flow 14.

[0105] Natural gas 16 is brought into contact with catalyst 24" in a high-pressure reactor 18 at a temperature of 850°C and a pressure of 18 bar, where a portion of the natural gas 16 is converted to hydrogen, producing a gas stream 62 which is a mixture containing hydrogen and unreacted natural gas. Graphite carbon is deposited on catalyst 2" to produce catalyst graphite carbon 14.

[0106] Referring to Figure 4, a process 100 for beneficiating a catalyst metal containing an ore, such as iron ore 102, is described.

[0107] Low-grade iron ore 102 passes through surge bin 104 to dusting reactor 106. In dusting reactor 106, the iron ore 102 comes into contact with hydrocarbon gas 108 at a temperature of 850°C and a pressure between 10 and 20 bar, generating graphite-coated iron flow 110 and waste flow 112 containing larger (over 1 mm) gangue particles. The size difference between graphite-coated iron flow 110 and waste flow 112 separates these flows. Graphite-coated iron flow 110 is passed through gas / solid separator 114, where the gas flow 116 is separated from the solid flow 118, and the solid flow 118 is passed to reduction reactor 120.

[0108] In the reduction reactor 120, graphite-coated iron particles in the solid flow 118 are brought into contact with hydrogen gas 122 at a temperature between 800°C and 900°C and a pressure between 10 bar and 20 bar to remove the carbon coating, leaving behind the iron concentrate flow 124. The reaction also forms a methane gas flow 126, which is recycled to the rest of the process. In the embodiment shown in Figure 2, the methane gas flow 126 is further brought into contact with the iron ore 102 passing through the surge bin 130 in the hydrogen reactor 127 at a temperature between 800°C and 900°C to produce hydrogen gas 122 and graphite powder 128. As shown in Figure 4, the hydrogen gas 122 is returned to the reduction reactor 120. [Examples] [Example 1]

[0109] Use of iron ore as a catalyst for the economical production of hydrogen and graphite through the thermal catalytic decomposition of methane. [Details of the experiment]

[0110] This invention provides a method that enables the use of low-grade iron oxide as a catalyst for the decomposition of methane. To demonstrate the catalytic activity of the low-grade iron oxide catalyst of this invention, samples of low-grade iron oxide were compared with samples of high-grade iron oxide. Two types of high-grade iron oxide were tested: hematite (99%, less than 5 μm, Sigma-Aldrich) and magnetite (95%, less than 5 μm, Sigma-Aldrich); and two iron ore samples: hematite ore (Pilbara mine) and goosite ore (Yandi mine). The ore samples were ground to less than 150 μm, and the rest were left untreated. The composition data, particle size distribution, and surface area of ​​all samples in their "untreated state (as received)" are shown in detail in Table 1. [Table 1] Table 1 - Data on composition, particle size, and surface area of ​​iron oxide samples

[0111] Each sample was placed in a separate, single-stage reactor. The reactor was a vertical 1 / 2" diameter stainless steel (SS316 Swagelok) tube with a 3 / 8" quartz tube liner. The quartz tube liner reduces the catalytic effect of the stainless steel reactor wall by limiting contact with the reacting methane gas. 20 g of catalyst sample was placed in a 3 / 8" "test tube-shaped" quartz chamber.

[0112] Figure 5 shows the XRD plots for high-grade iron oxide catalyst samples, i.e., analytical grade (hematite and magnetite), and low-grade iron oxide catalyst samples (hematite ore and goosite ore).

[0113] Each sample was reacted at temperatures ranging from 750°C to 950°C using 10 sccm of pure methane (UHP) at reaction pressures between 1 bar and 9 bar (absolute value). After complete inactivation (approximately 19 hours), the reaction was terminated, and the samples were cooled with 20 sccm of pure nitrogen (UHP). The weight of the resulting carbon (and embedded catalyst particles) was measured to determine the total carbon yield per gram of the iron catalyst used.

[0114] Figure 6 shows the results of these experiments under reaction conditions of 850°C and atmospheric pressure. The results indicate that low-grade iron ore samples performed almost identically to high-grade oxides, with carbon yields ranging from 9.2 to 8.9 grams per gram of iron, correspondingly with carbon purityes of 90% to 89% by weight, respectively. These values ​​were shown to correlate closely with those derived by quantitative XRD, with a difference of less than 2% by weight (shown as hollow shapes in Figure 6).

[0115] As those skilled in the art will understand, a common method for increasing catalyst activity is to make the catalyst extremely pure in order to increase the reaction area. Iron oxide catalysts, such as the high-grade iron oxide samples tested, must be specifically synthesized to have a purity exceeding 99%. The results of this experiment demonstrate that high conversion rates and yields can be obtained even when using low-grade catalysts under the specific process conditions of the present invention. [Example 2] Thermocatalytic methane decomposition using counterflow MPR Counterflow

[0116] The three-reactor counterflow MPR was assembled in a cascade configuration as shown in the schematic diagram in Figure 7.

[0117] An experimental evaluation of a counterflow MPR system was conducted using a static (discontinuous) system. This was done by testing the effect of pressure on methane conversion efficiency and carbon yield. The results showed that increasing the pressure decreased methane conversion and increased carbon yield, while conversely, lower pressure increased methane conversion and decreased total carbon yield. [Details of the experiment]

[0118] The effect of reaction pressure on the limit of methane conversion

[0119] The reactor setup included three independent reactor stages (3 × 1 / 2” OD316SS Swagelok, 70 mm length) operating at isothermal temperatures of 850°C, with different back pressure settings (12 bar, 4 bar, and atmospheric pressure). Instead of connecting the reactors in series, they were individually fed and analyzed to assess their individual performance. The feed gas composition for each reactor was set to induce operation in series, and each reactor was operated at the theoretical maximum possible conversion at the reaction pressure (Table 2). The performance of each stage was determined by monitoring the wastewater from each reactor using a gas chromatograph (GC). A schematic diagram of this process is shown in Figure 8. Excess iron oxide was used to induce conditions for a continuous catalytic flow within this static system, providing a momentary glimpse of the expected steady-state continuous operation. [Table 2] Table 2 - Process conditions for MPR experiments

[0120] The results obtained from this experiment are shown in Figure 9, and they correlate well with the theoretical expectations, thus validating the theory. The three reactor stages correlated well with the expected thermodynamic equilibrium limit (shown by the dashed line) over a period of more than 20 hours, after which the reaction terminated. It is clear that, when using the MPR system, high hydrogen concentrations do not affect the reaction's ability to achieve transformation at the thermodynamic equilibrium limit.

[0121] These results demonstrate that a continuous MPR system can maintain stable conversion at the thermodynamic equilibrium limit, regardless of the hydrogen level. [The effect of pressure on product yield]

[0122] The effect of reaction pressure was tested using 20 mg of catalyst at a pressure interval of 1 bar, with all other reaction conditions remaining the same as in previous experiments (i.e., 850°C, 20 sccm of methane, auto-reduction, and a duration of 19 hours).

[0123] The results show a positive linear relationship between reaction pressure and total carbon yield. As shown in Figure 10, the profile indicates that the carbon yield per gram of iron increases from 9 g to 22 g over a pressure range from atmospheric pressure to 9 absolute bars, corresponding to carbon purities of 90% to 96%, respectively. [Empirical calculation of catalyst flow rate]

[0124] The overall feasibility of an MPR system depends on the mass flow balance. This is particularly important for counterflow MPRs because the catalyst mass flow rate is strictly interdependent with (1) the number of stages in the pressure reactor, (2) the pressure range, and (3) the catalyst's carbon capacity profile. Empirical mass balance calculations were performed to determine the feasibility of achieving this balance.

[0125] The catalyst flow rate in each reactor can be determined by dividing the carbon deposition rate in each reactor by the catalyst availability, with each reactor being bounded by its pressure range.

number

[0126] The greatest constraint of a counterflow MPR configuration is balancing the catalyst mass flow rate across all reactor stages to enable continuous operation. The required catalyst flow rate at each stage depends on (1) the number of reactor stages and (2) the catalyst's carbon capacity profile relative to the pressure. This balance is shown in Figure 11.

[0127] The purpose of this calculation is to determine the number of pressure stages required to balance the catalyst flow rate across all stages, given the carbon capacity profile of the catalyst and the reaction temperature (assuming isothermal conditions).

[0128] If the catalyst mass flow rate is set so that it is completely deactivated as it leaves each reactor stage, the catalyst availability at each stage is the difference between the total catalyst availability at the reactor pressure and that of adjacent reactors at lower pressures. Therefore,

number

[0129] 'n' is the reactor number (n=1 is the reactor with the lowest pressure).

[0130] Therefore, the mass flow rate of the catalyst at each reactor stage is:

number

[0131] In a reactor system with only one reactor (n = 1), there are no stages for reactor (n - 1) and reactor (n + 1), so

Number

[0132] Similarly, in the case of a two-stage reactor, there is no reactor (n - 1) and reactor (n + 2), and in the case of a three-stage reactor, there is no reactor (n - 1) and reactor (n + 3). [Catalyst mass flow rate balance]

[0133] To make a multi-stage process continuous, the catalyst flow rates must be equivalent.

Number

Number

[0134] Under isothermal conditions, this is

Number

[0135] When reactor 'R1' operates at atmospheric pressure and operates at TEL, ξ R1 is known, and ξ R2 can be solved using the above equation. This solution will solve for the pressure required for reactor 2 to have an equal catalyst flow rate.

[0136] This process is also carried out when the number of reactors is larger. Number of reactor stages: 3

number

number

[0137] The above can be supplemented by the number of additional reactor stages. [result]

[0138] The empirical results using linearly extrapolated values ​​for pressures exceeding 9 bar (absolute value) are shown as a graph in Figure 12. These results indicate that the counterflow MPR will consume considerably less catalyst than the parallel flow process in all cases. A counterflow process with five reaction stages requires only 19% of the catalyst required by a single reactor, compared to 42% for the same number of stages in the parallel flow process. However, the counterflow process can only have a maximum of five reaction stages for a constant catalyst mass flow rate across all stages. In contrast, the number of stages in the parallel flow process is unlimited. However, the yield at each stage diminishes, and it will be understood that the overall catalyst requirement is significantly higher than in the counterflow option. The catalyst mass flow rate is 2,000 m 3 It is calculated based on the assumption of a hydrogen output flow rate of / hr. [Example 3] Iron ore dressing Experiment details

[0139] Typical low-grade iron ore rocks consist of clearly distinguishable sections of high-grade iron oxide and low-grade equivalents. This type of rock is known as banded iron formation (BIF). A 6.39 g sample of BIF iron ore was prepared, and its properties are analyzed as shown in Table 3. [Table 3] Table 3 - Sample Analysis

[0140] The sample was packed into the floor of a stationary reactor and exposed to methane gas at 900°C and atmospheric pressure for 4 hours. After the reaction, the high-grade iron oxide stripes were broken down, while the majority of the lower-grade equivalents remained unaffected.

[0141] Without being constrained by theory, the inventors understand that the initial reaction is the reduction of aggregated iron oxide ore to iron carbide, releasing water vapor, H2, CO2, and trace amounts of CO. Continuing the reaction, the aggregated iron carbide is broken down by metal dusting (as previously described), and in the absence of oxides, the system releases only H2 gas. In this dusting, all iron species are broken down into micron and nano-sized fragments by the surrounding graphite layer. The gangue of the iron ore (typically a highly stable mineral containing SiO2 and Al2O3) remains unaffected and intact by these process conditions. Therefore, the products of this process are larger gangue aggregates and fine particles of ferric / iron carbide surrounded by graphite. These two types can then be separated by physical screening, taking advantage of the size and density differences between the iron species and the gangue.

[0142] Table 4 shows the compositional data of the samples after reaction and physical separation by size. [Table 4] Table 4 - Sample Analysis

[0143] Analysis showed that the majority of the iron species could be separated by size separation, with sample A corresponding to the majority of the iron. Since the compositional data was measured by XRF analysis, which requires pre-oxidation of the sample, all iron species are shown as oxides rather than ferrites. Energy-dispersive X-ray spectroscopy analysis performed before calcination showed that the iron species were ferrites. Empirically, we can calculate that by removing this oxide from the iron composition, the process can extract a product that is 85 wt% iron from the original overall rock composition of approximately 35 wt%.

[0144] Next, it is assumed that graphitic carbon can be removed from ferric / iron carbide surrounded by graphite through a process called methanation. In this reaction, iron / carbon particles are brought into contact with hydrogen gas at high temperatures, and methane gas is formed by reaction 2 below. C+2H2→CH4(2)

[0145] Because the iron particles are very small and this reaction is exothermic, the iron particles agglomerate to form larger particles of pure iron.

[0146] Next, it is assumed that graphite-like carbon can be removed from graphite-encased ferric / ferric carbide by bringing it into contact with hydrogen gas at 800°C and 20 bar.

[0147] The advantage of the present invention's ore beneficiation method over conventional iron ore beneficiation methods is that, in addition to the removal of gangue, the generated iron oxide species is reduced (oxygen is removed, leaving ferric iron). This reduced iron is 90% to 95% iron by weight, compared to 55% to 63% iron by weight in high-grade iron ore (70% is the theoretical maximum). Reduced iron is a higher quality product than iron ore and is therefore more expensive. Also, since no ballast oxygen is transported, the transport cost of the reduced iron product is likely lower, resulting in savings of 30% to 40% by weight and less than 50% by volume. Conventional ore beneficiation processes used in the iron ore industry include crushing, magnetic separation, flotation, gravity separation, concentration / filtration, and coagulation.

[0148] Those skilled in the art will understand that the inventions described herein are subject to modifications and alterations other than those described in detail. The inventions include all such modifications and alterations. Furthermore, the inventions include all, individually or collectively, all steps, features, formulations, and compounds mentioned or indicated in the specification.

Claims

1. A process for producing hydrogen and graphitic carbon from hydrocarbon gases, The method includes contacting a catalyst with the hydrocarbon gas at a temperature between 600°C and 1,000°C to catalytically convert at least a portion of the hydrocarbon gas into hydrogen and graphitic carbon. The catalyst is a low-grade iron oxide obtained from iron ore. The hydrocarbon gas is selected from the group consisting of methane, ethane, ethylene, propane, and / or butane; and A process characterized in that, upon contact with the hydrocarbon gas, all iron oxide in the catalyst is encapsulated by the graphitic carbon and decomposed into micron and nanoscale fragments.

2. The process according to claim 1, wherein the pressure is higher than atmospheric pressure.

3. The process according to claim 1, wherein the pressure is between 0 bar and 100 bar.

4. The process according to any one of claims 1 to 3, wherein the temperature is between 700°C and 950°C.

5. The process according to any one of claims 1 to 4, wherein the temperature is between 800°C and 900°C.

6. The process according to any one of claims 1 to 4, wherein the temperature is between 650°C and 750°C.

7. The process according to any one of claims 1 to 6, wherein the hydrocarbon gas is methane.

8. The process according to any one of claims 1 to 7, wherein the step of bringing the catalyst into contact with the hydrocarbon gas is performed in a plurality of pressurized reactors arranged in series.

9. The process according to claim 8, wherein the series arrangement of the pressurizing reactors allows gas to flow from the first pressurizing reactor to the subsequent pressurizing reactors, and each subsequent pressurizing reactor in the series arrangement operates at a lower pressure than the preceding pressurizing reactor, thereby allowing the gas to move to the pressurizing reactor at the lower pressure.

10. The process according to claim 9, wherein each of the pressurized reactors is provided with an unreacted catalyst.

11. The process according to claim 8, wherein the series arrangement of the pressurized reactors allows the catalyst to flow from the first pressurized reactor to the subsequent pressurized reactors, and each subsequent pressurized reactor in the series arrangement operates at a higher pressure than the preceding pressurized reactor, thereby allowing the catalyst to move to the pressurized reactor at the higher pressure.

12. The process according to claim 11, wherein unreacted hydrocarbon gas is supplied to each of the pressurized reactors.

13. The process according to claim 8, wherein the series arrangement of the pressurized reactors allows both the hydrocarbon gas and the catalyst to flow in opposite directions between the pressurized reactors.

14. The process according to claim 13, wherein an unreacted catalyst is provided in the pressurized reactor with the lowest pressure, and an unreacted hydrocarbon gas is provided in the pressurized reactor with the highest pressure, and the catalyst is moved between the chambers to the higher pressure as a counterflow to the gas flow between the chambers.

15. A method for beneficiating catalyst metals containing ore, The method includes contacting a catalyst metal containing the ore with a hydrocarbon gas at a temperature between 600°C and 1,000°C to form a carbon-coated metal species. The catalyst metal containing the aforementioned ore is a low-grade iron oxide obtained from iron ore. The hydrocarbon gas is selected from the group consisting of methane, ethane, ethylene, propane, and / or butane; and A method characterized in that, upon contact with the hydrocarbon gas, all iron oxide in the catalyst is encapsulated in graphite-like carbon and decomposed into micron and nanoscale fragments.

16. The method according to claim 15, wherein the pressure is higher than atmospheric pressure.

17. The method according to any one of claims 15 to 16, wherein the pressure is from 0 bar to 100 bar.

18. The method according to any one of claims 15 to 17, wherein the temperature is between 700°C and 950°C.

19. The method according to any one of claims 15 to 18, wherein the carbon-coated metal species is a graphite-coated metal species.

20. The method according to claim 19, wherein graphite is removed from the graphite-coated metal species by contacting the graphite-coated metal species with hydrogen gas at a temperature of 700°C to 900°C.

21. The method according to claim 20, wherein the removal of graphite from the graphite-coated metal species is performed in a pressurized-reducing reactor at a pressure of 0 to 100 bar.

22. The method according to claim 20 or 21, wherein the step of contacting the graphite-coated metal species with hydrogen gas at a temperature of 700°C to 900°C produces methane that is recycled to produce hydrogen.

23. The method according to claim 22, wherein the hydrogen generated in the methane recycling process is used in a step of removing graphite from the graphite-coated metal species by contacting the graphite-coated metal species with the hydrogen gas at a temperature of 700°C to 900°C.

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