Catalytic material for methane pyrolysis and hydrogen and solid carbon production with essentially zero atmospheric carbon emissions

Abstract

A catalyst for pyrolysis of a hydrocarbon such as methane or natural gas includes a waste product heap configured to facilitate decomposition of the hydrocarbon into hydrogen and carbon. The waste product is one of a bauxite residue, a mill tailing, or a slag. The waste product heap can be broken into a powder form or a chip form.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. non-provisional patent application serial number 17 / 502,628, filed on October 15, 2021, which claims the benefit of and priority to U.S. provisional patent application serial number 63 / 093,399, filed on October 19, 2020, each of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to the production of hydrogen and solid carbon materials via hydrocarbon pyrolysis. Specifically, the present disclosure relates to catalysts for the pyrolysis of methane or natural gas, the catalysts comprising waste products. Background Art

[0004] Decarbonization of the energy sector is crucial to addressing environmental concerns related to global warming and climate change. Hydrogen, particularly pure H2, is a well-known carbon-free energy carrier and is seen by many as a promising alternative to fossil fuels for decarbonizing the energy sector, particularly for its use in electricity generation and transportation. The emergence of fuel cell technology is facilitating this alternative, as fuel cells operate on hydrogen, offer high electrical efficiency, and offer other environmental benefits.

[0005] However, hydrogen is not found in a free molecular state on Earth. Therefore, free molecular hydrogen must be extracted from hydrogen-containing compounds. The most mature technology involves extracting hydrogen from water via electrolysis (water dissociation). This process is energy intensive because the H-O bonds in water are very stable and a lot of energy is needed to break them. In order to produce one cubic meter of hydrogen via water electrolysis, more than 4 kW-h of electricity is required. Exacerbating the problem is the source of the electricity consumed in pure H2 production and the environmental impact of its production. Since in many parts of the world, electricity production is associated with large emissions of carbon and other atmospheric pollutants, the environmental footprint of this technology is questionable.

[0006] An alternative approach is to extract hydrogen from hydrocarbons such as methane (CH4), which is the main component of natural gas (>90-95%). While this is a viable and mature method, it does emit carbon dioxide (CO2) as a result of the carbon contained in the hydrocarbons. While the amount of CO2 emitted may be small, it is not zero. However, due to the very large global supply of natural gas and its low carbon emissions, this method is a technology that can serve as a transition between all-carbon and zero-carbon methods.

[0007] Another alternative method to produce "blue hydrogen" (i.e., hydrogen containing virtually no carbon emissions) is to decompose or pyrolyze methane or natural gas into gaseous hydrogen and solid carbon. Such a method produces the pure hydrogen gas needed that can be used directly in a fuel cell to produce electricity and limit the CO2 emissions to zero, as described in U.S. Patent No. 6,670,058 to Muradov. The solid carbon byproduct can be used in industrial processes or it can be easily disposed of underground. If biogas (or biomethane) is used instead of natural gas, this method is "negative" in carbon emissions because the carbon contained in biomethane is carbon absorbed from the atmosphere. The energy "penalty" of this method is defined as the energy loss caused by the decomposition of methane to produce hydrogen and the use of the hydrogen in a fuel cell to generate electricity, which is less than 15% compared to the use of natural gas in a turbine to generate electricity. If the produced carbon is utilized in industrial processes, the penalty will be even smaller or even "negative".

[0008] Methane pyrolysis requires very high temperatures, typically greater than 1200°C. Suitable catalysts can be used to lower the required activation temperature of methane required for pyrolysis. In the presence of a suitable catalyst, methane decomposition can occur at 800-900°C. The most promising catalysts include nickel (Ni), iron (Fe), and cobalt (Co) supported on metal oxide materials such as aluminum oxide (AI2O3), magnesium oxide (MgO), and the like. However, methane decomposition on such catalysts is not practically and economically feasible because the catalysts accumulate carbon on their surface and deactivate after a short period of use. Removing the accumulated carbon and reusing the catalyst is complex and expensive. Thus, the solid material containing the catalyst and the accumulated carbon is often disposed of together. Since the cost of the catalyst is substantial, this does not favor the economic feasibility of the method. Therefore, there is a need for a practical, economically feasible, and effective catalyst in reducing the temperature requirement of methane pyrolysis. SUMMARY

[0009] The present disclosure relates to a catalyst for methane pyrolysis, the catalyst comprising a waste product heap. The waste product is configured to facilitate decomposition of a hydrocarbon into hydrogen and carbon. The waste product is one of a refined bauxite residue, a mill scale, or a slag.

[0010] In one aspect, the catalyst can include a substructure layered with the waste product.

[0011] In some aspects, the substructure can be at least partially made from the waste product.

[0012] In other aspects, the waste product can be enhanced by a nickel, cobalt, or iron additive.

[0013] In other aspects, the substructure can be made at least in part from nickel, cobalt, iron, aluminum oxide, or magnesium oxide.

[0014] In one aspect, the waste product pile is broken into a powder or chip form.

[0015] In some aspects, the waste product can be a slag including at least one of a steel slag, a copper slag, or a nickel slag.

[0016] Another aspect of the disclosure provides a method for manufacturing hydrogen gas. The method includes passing a hydrocarbon over a waste product catalyst; heating the hydrocarbon and waste product catalyst; thermally catalytically decomposing the hydrocarbon into hydrogen gas and solid carbon; and collecting the hydrogen gas in a container.

[0017] In some aspects, passing a hydrocarbon over a waste product catalyst can include passing natural gas or methane over a waste product catalyst.

[0018] In additional aspects, the method can further include collecting the solid carbon deposited on the waste product catalyst.

[0019] In other aspects, passing a hydrocarbon over a waste product catalyst can include passing a hydrocarbon over a waste product catalyst pile.

[0020] In the disclosed aspects, passing a hydrocarbon over a waste product catalyst can include passing a hydrocarbon over a waste product catalyst that can include at least one of a bauxite residue, a slag, or a mill scale.

[0021] In other alternatives, passing a hydrocarbon over a waste product catalyst includes passing a hydrocarbon over a waste product catalyst that can include a substructure. The waste product material layer can be an outer layer on the substructure.

[0022] In other aspects, the waste product catalyst can be housed in a reactor.

[0023] In still further aspects, the reactor is a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, a trickle bed reactor, a rotating bed reactor, or a slurry reactor.

[0024] In the disclosed aspects, the method can include processing the waste product catalyst into a powder or chip form.

[0025] In aspects, the method can include heating the hydrocarbon and waste product catalyst to about 750°C to about 950°C.

[0026] In aspects, the method can include heating the hydrocarbon and waste product catalyst to about 500°C to about 1300°C.

[0027] These and other features and advantages of the present disclosure will become apparent from the following description and associated drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] A better understanding of the features and advantages of the present disclosure will be obtained by referring to the following detailed description and accompanying drawings which set forth illustrative aspects, in which:

[0029] Figure 1 It is an image of a pile of catalytic material from bauxite residue;

[0030] Figure 2 It is an image of a pile of mill scale catalytic material;

[0031] Figure 3 is an image of exemplary production rates of hydrogen when bauxite residue is used as a catalytic material;

[0032] Figure 4 is an image of exemplary production rates of hydrogen when mill scale is used as the catalyst material;

[0033] Figure 5 is an image of a method for producing hydrogen according to another aspect of the present disclosure; and

[0034] Figure 6 It is a cross-sectional view of a flat rod-shaped spent catalyst. DETAILED DESCRIPTION

[0035] While the present disclosure will be described in terms of specific embodiments, it will be apparent to those skilled in the art that various modifications, rearrangements, and substitutions can be made without departing from the spirit of the present disclosure.

[0036] The description herein presents many specific details that are incorporated to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that the present disclosure may be practiced without some or all of these specific details. On the other hand, well-known process steps, procedures, and structures have not been described in detail in order to avoid unnecessarily obscuring the present disclosure.

[0037] The production of pure hydrogen and solid carbon materials through the pyrolysis or thermocatalytic decomposition of methane is an integral part of the development of the hydrogen economy. Improving the source and properties of the catalysts used in the reaction is an important aspect of increasing the feasibility of producing hydrogen from natural gas or methane, of which methane is the main component. The enhancement of catalytic properties is usually carried out in terms of reaction rate, minimization of operating temperature, and the ability to maintain thermochemical stability during the deposition of giant nanocarbons. Therefore, various metal-based and carbon-based catalysts have been introduced. Metal-based catalysts are superior to carbon catalysts in terms of their hydrogen production percentage and reaction rate.

[0038] Transition metal based, in particular nickel, iron and cobalt based catalysts are often used to improve catalytic reactions during pyrolysis. Nickel based catalysts are distinguished from metal based catalysts by their relatively low cost, low toxicity, excellent activity, stability and environmentally friendly characteristics. Metal based catalysts have a longer catalytic life by maintaining a nanocarbon formation mechanism that keeps the metal active sites on top of the catalyst facing the reaction medium. The growth mechanism of nanocarbon or solid carbon product from the pyrolysis process involves the diffusion of deposited carbon through the active metal sites. The diffused nanocarbon then precipitates on the other side of the metal particle to form longer carbon filaments.

[0039] The catalytic activity and stability of the catalyst used in the process and the properties of the nanocarbon produced are very relevant in thermal catalytic decomposition (TCD) as both play a crucial role in determining the overall yield and structure of the solid carbon byproduct and hydrogen produced. Solid carbon accumulates on the catalyst until the catalyst is saturated with solid carbon, thereby deactivating the catalyst. When deactivation approaches completion, the catalyst along with its contained solid carbon can be disposed of in a suitable manner or it can be used in other processes.

[0040] The solid carbon byproduct of methane pyrolysis or TCD is typically in the form of nanocarbon, graphitic carbon or carbon nanotubes. This provides additional economic benefits to the production of hydrogen via pyrolysis or TCD, as well as environmental benefits in some applications as it reduces the need to dispose of solid carbon that would otherwise be useless. For example, graphitic carbon byproducts can be used in various industries and consumer applications such as the production of pencil leads, high temperature crucibles, dry cells, electrodes, or as lubricants, among many other applications known to those of ordinary skill in the art. Carbon nanotubes (CNT) are cylinders of one or more layers, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT) of graphene (lattice) with diameters between 0.8 nm and 2 nm for SWCNT and between 5 nm and 20 nm for MWCNT. CNTs are structural materials with desirable properties and are used in applications including, but not limited to, energy storage, device modeling, automotive parts, boat hulls, sporting goods, water filters, thin film electronics, paints, actuators, and electromagnetic shields.

[0041] The provision of low cost, environmentally friendly and abundant catalytic materials mitigates the need to improve the properties of expensive catalytic materials or develop methods to reuse the catalysts.

[0042] The present disclosure describes a series of “waste-product” catalysts, or waste products that form catalytic materials, that can facilitate the thermal catalytic decomposition (pyrolysis) of methane or natural gas into hydrogen gas and solid carbon, and can be used for low-carbon, approximately zero-carbon, or ‘negative’ carbon production of pure hydrogen gas. The catalysts are carbon neutral, allow for carbon consumption, and are environmentally friendly because they are composed of waste that must be disposed of anyway. The waste-product catalysts are produced from waste and allow for the pyrolysis or thermal catalytic decomposition (TCD) of methane at lower temperatures than without the use of a catalyst. Furthermore, due to the abundance of these wastes, it is economical and feasible to replace used “waste-product” catalysts because the materials would otherwise be disposed of, for example, in a landfill. Thus, this mitigates the problem of solid carbon deposits building up on and deactivating the catalytic material, which can be more expensive. Waste-product catalysts can include slag, mill scale, bauxite residue, or similar waste products containing iron levels sufficient for TCD.

[0043] The waste-product catalysts are used to crack open methane or natural gas. When these materials are used as waste-product catalysts in methane TCD, the following reaction occurs:

[0044] CH4 2H2 + C AHo ~ 75 kJ / mol (Equation 1)

[0045] Referring to Figure 1 , the waste-product catalyst is produced from bauxite residue (bauxite tailings), colloquially known as “red mud.” The red mud is dried and used as a catalyst in “powder” or “chips” form. Red mud is primarily composed of iron oxides. Bauxite residue is a byproduct of the process of extracting aluminum from bauxite, specifically a process known as the Bayer process, known to those of ordinary skill in the art of aluminum extraction.

[0046] In the Bayer process, open-pit mined bauxite is treated with sodium hydroxide (also known as hot caustic soda), which can selectively dissolve aluminum from a series of other mineralized metals. The end product is aluminum oxide (AI2O3) for the production of aluminum metal, as well as bauxite residue. Approximately 1-1.5 tons of red mud are produced for every ton of aluminum oxide produced. Typically, the red mud produced is stored in a pond, has few other uses, and is not environmentally friendly. Given that the annual production of aluminum oxide as of 2018 was approximately 126 million tons, resulting in 160 million tons of red mud, it is desirable to have a proper and environmentally friendly use for the red mud.

[0047] Manufacturing a waste-product catalyst with red mud not only provides for the performance of an efficient and effective pyrolysis, but also reuses a waste product produced from the Bayer process, thereby reducing the environmental impact of both the pyrolysis process and the Bayer process. Furthermore, the abundance of red mud makes it an attractive economic material for a catalyst.

[0048] Bauxite residue can be dried in various ways, such as oven drying or sun drying, and then processed to form a "powder" or "chip" (small pieces and flakes) catalytic heap. The dried red mud can be placed into and contained by a chemical reactor for pyrolysis. The reactor can be a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, a trickle bed reactor, a rotating bed reactor, or a slurry reactor. Any suitable reactor known to one of ordinary skill in the art of chemical reactors or pyrolysis can be used. Placing the dried red mud catalytic heap directly into the chemical reactor, in addition to saving carbon and producing hydrogen, also reduces the cost of producing catalytic materials because no further processing of the catalyst is needed.

[0049] In some aspects, the spent product catalyst can include a catalytic substructure coated with a layer of refined or dried red mud. In some aspects, the substructure can be made from red mud and then dried red mud can be layered onto the catalytic substructure. The dried red mud can be configured to form an entire catalytic structure. In some aspects, nickel (Ni), cobalt (Co), or iron (Fe) metals or compounds can be added to the red mud to enhance the catalytic performance of the red mud.

[0050] Bauxite residue can contain 30-60 wt% iron (III) oxide (Fe203), 10-20 wt% aluminum oxide (AI2O3), 3-50 wt% silicon dioxide (Si02), 2-10 wt% sodium oxide (Na20), 2-8 wt% calcium oxide (CaO), and about 0-25 wt% titanium dioxide (Ti02). Additionally, trace amounts of MgO are often found in red mud. AI2O3, Si02, MgO, and Ti02are known in the art to improve catalytic performance, as discussed by Ashik et al. in the article titled "A review on methane transformation to hydrogen and nanocarbon: Relevance of catalyst characteristics and experimental parameters on yield" in the journal Renewable & Sustainable Energy Reviews, March 2017. Specifically, Si02as a catalyst additive is an effective material for enhancing catalytic reactions in pyrolysis. Thus, dried bauxite residue in a "powder" or "chip" heap is a desirable catalytic material.

[0051] The red mud can be refined to include the desired amount of its respective components. The red mud can be layered and stacked on a substructure that includes Co, Ni, Fe, or metal oxides such as AI2O3 or MgO. The catalytic substructure can be any shape, size, or geometry known to one of ordinary skill in the art. The catalytic substructure can be a cylinder, a cube, a rod, a honeycomb, or any other desired shape.

[0052] In another aspect of the disclosure, the waste product catalyst includes solid particles or flakes derived from waste material from steel production and processing and composed of steel without any admixture. In some aspects, the solid particles or flakes can be mill scale produced as a byproduct of a rolling process. Mill scale is a flaky surface or thin layer of iron oxide of hot-rolled steel and is composed of mixed iron oxides such as iron(II) oxide (FeO), iron(III) oxide (Fe2O3), and iron(II, III) oxide (Fe3O4, magnetite). In some aspects, the mill scale waste material can be composed of about 40% to about 100% Fe2O3 or about greater than 90% Fe2O3. The mill scale is collected into a catalytic stack and placed in a suitable reactor such as a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, a trickle bed reactor, a rotating bed reactor, or a slurry reactor. Any suitable reactor known to one of ordinary skill in the art of chemical reactors or pyrolysis can be used.

[0053] In another aspect of the disclosure, a slag is a waste material that is a byproduct left after a metal has been separated from its ore and can be used as all or part of a waste product catalyst. The slag is collected into a catalytic stack to form a waste product catalyst. The slag can be broken into a “powder” or “chips” form and collected into the catalytic stack. The catalytic stack of slag is placed in a suitable reactor as described above with respect to mill scale and red mud.

[0054] Slags are generally composed of a mixture of metal oxides and silicon dioxide (SiO2), but can also include metal sulfides, magnesium oxide (MgO), and other elemental metals. The typical composition of various types of slag is shown in Table 1:

[0055]

[0056] Table 1

[0057] The slag can be, for example, a steel slag produced during the purification of pig iron (also known as cast iron) in the iron and steel industry. The purification of pig iron is often carried out in a basic oxygen furnace (BOF) or an electric arc furnace (EAF) to oxidize various residual gangues that are separated by floating on the iron melt. Table 2 shows an exemplary composition of steel slag produced using a BOF or EAF in weight percent (wt%).

[0058]

[0059] Table 2

[0060] In some aspects, the slag can be nickel slag (Ni slag). Ni slag is produced as a waste product in the production of nickel metal. Nickel ore can be a nickel pyrite that is mixed with Fe and S as (Ni,Fe)9S8, which is smelted to produce nickel matte. Nickel matte contains nickel and iron sulfides. Nickel matte is then processed in an electric furnace where the iron in the nickel matte is oxidized and can combine with silica to produce a slag containing about 30% or less to about 40% or more FeO by weight. A converter can further purify the nickel matte from the iron oxides still in the nickel matte to produce a slag containing about 60% or less to about 66% or more FeO. Table 3 shows an exemplary composition of Ni slag.

[0061] Component Electric furnace wt.% Converter wt.% FeO 32-40 60-66 Fe2O3 2-7 13-18 CaO 3-6 7-9 SiO2 32-42 5-8 Al2O3 7-12 0.5-1.5 Cr2O3 2-3 1-5 MgO 3-6 5-8

[0062] Table 3

[0063] In other aspects, the slag can be copper slag (Cu slag) produced as a waste product in the smelting of copper ore, such as copper iron sulfide (e.g., CuFeS2or Cu5FeS4) to produce copper matte. The copper matte is then processed to remove iron, sulfur, and gangue material from the copper matte. Silica can be added to the melt as the silica interacts with the iron oxides of the copper matte to form a floating layer that can be separated from the melt. The iron oxides mix with the silica to form copper slag. Table 4 shows an exemplary composition of Cu slag.

[0064] Component wt.% F2O3 55-70 Al2O3 0.5-5 SiO2 25-35 CaO 0.15-6

[0065] Table 4

[0066] In some aspects, the slag or mill scale can be layered onto the catalytic substructure or form the entire catalytic substructure. In some aspects, the catalytic substructure can include multiple layers of slag and / or mill scale.

[0067] In another aspect of the disclosure, raw iron ore, while not a waste product, is broken into a “powder” or “chip” form and collected into the catalytic stack for pyrolysis in a chemical reactor. Iron ore is typically mined for the extraction of its iron for use in steelmaking and is therefore not typically a waste product, but rather a raw material that is processed into a future product. Iron ore is a cheaper material compared to many standard catalysts in their unprocessed state. Slag and mill scale are the remnants or waste products of iron ore after it has been processed.

[0068] Slag, mill scale, and red mud provide attractive materials for producing waste product catalysts for pyrolysis because they are materials that already need to be disposed of and have the properties needed for pyrolysis. Table 5 below provides a comparison of carbon accumulation rates for red mud and mill scale relative to typical catalytic materials. The higher the ratio of grams (g) of carbon contained per gram (g) of catalyst, the more hydrogen is produced because more carbon is separated from the hydrocarbon (e.g., methane) and accumulated on the catalyst at higher rates. The amount of carbon accumulated on the waste product catalysts (red mud and mill scale) is more advantageous compared to those catalysts conventionally used. It is notable that the carbon accumulation rate of mill scale exceeds many other catalysts.

[0069]

[0070] Table 5

[0071] Referring to Figure 3 , a graph showing the rate of hydrogen production over time when using a dry red mud catalytic stack for the thermal catalytic decomposition (pyrolysis) of methane in an example experiment is shown. The methane was approximately pure and was decomposed at 900 °C. The dry red mud used in the example experiment was 300 milligrams (mg) by weight, containing approximately 100 mg of Fe. Approximately 500 mg of carbon was deposited on the red mud after 220 minutes. Approximately 1,850 cubic centimeters (cc) of hydrogen (H2) was produced after 220 minutes, which is equivalent to approximately 0.55 kilograms (kg) of H2per 1 kg of red mud. The rate of hydrogen production via pyrolysis using the red mud catalytic stack in the example experiment ranged from approximately 15 cc / minute (cc / min) to approximately 5 cc / min.

[0072] Referring to Figure 4 , a graph showing the rate of hydrogen production over time when using a mill scale catalytic stack for pyrolysis in an example experiment is shown. The methane was approximately pure and was decomposed at 900 °C. The mill scale catalytic stack used in the included embodiment was 300 mg by weight. Approximately 2850 mg of carbon was deposited on the iron slag catalytic stack after 2,000 minutes. Approximately 10,600 cc of H2was produced, which is equivalent to approximately 3.15 kg of H2per 1 kg of iron slag catalytic stack. The rate of hydrogen production via pyrolysis using the mill scale catalytic stack increased to a peak of approximately 25 cc / min in the first 120 minutes and decreased to approximately 3 cc / min after 2,000 minutes.

[0073] In another aspect of the disclosure, a method 500 for producing hydrogen gas from a hydrocarbon, such as methane or natural gas, includes the step 510 of passing the hydrocarbon over a spent product catalyst of the disclosure. In step 520, the method includes heating the hydrocarbon to a desired temperature in the presence of a spent product catalyst of the disclosure. In some aspects, the hydrocarbon can be heated to 500 °C to about 1300 °C. In some aspects, the hydrocarbon and spent product catalyst are heated to about 750 °C to about 950 °C. In another step 530, the hydrocarbon (e.g., methane) is decomposed into pure hydrogen gas and solid carbon. The method includes producing solid carbon on the surface of the spent product catalyst. In some aspects, only solid carbon and no gaseous carbon is produced as a byproduct. In another step 540, the method includes collecting the hydrogen gas in a container. The method can include using the produced hydrogen gas to heat the catalyst. In another step 550, the method includes collecting the solid carbon from the spent product catalyst. In some aspects, the spent product catalyst is a catalytic pile comprising at least one of red mud, mill scale, or slag. In some aspects, the solid carbon and spent product catalyst are disposed of underground to prevent carbon from escaping into the atmosphere.

[0074] Reference Figure 6 Exemplary spent product catalyst 600 includes a substructure 610 and a spent product outer layer 620. Substructure 610 can be made of any suitable material, such as Ni, Co, or Fe, a metal oxide (such as MgO or AI2O3), or a non-metal (such as a ceramic). Spent product layer 620 can include one or more spent products, such as bauxite residue, slag, or mill scale. In some aspects, spent product layer 620 can include multiple sub-layers of spent products. Additives can be mixed with the spent products to enhance the ability of the spent products to promote pyrolysis and collect solid carbon accumulation. While Figure 6 A rod-shaped spent product catalyst is shown, but any suitable shape or structure can be used. In some aspects, substructure 610 is configured to support a spent product catalytic pile. In some aspects, spent product layer 620 is a spent product catalytic pile disposed on an upper surface of substructure 610.

[0075] Certain aspects of the disclosure can include some or all of the advantages described above and / or one or more other advantages that will be apparent to those of ordinary skill in the art in light of the drawings and descriptions included herein, or can include no advantages at all relative to the prior art. Further, while specific advantages have been enumerated above, various aspects of the disclosure can include all or some of the enumerated advantages or none of the enumerated advantages, or can include other advantages not listed above.

[0076] The phrases “in one aspect,” “in some aspects,” “in various aspects,” “in certain aspects” or “in other aspects” can each refer to the same or different aspects of the present disclosure. The phrase “A or B” means “(A), (B), or (A and B).” The phrase “at least one of A, B, or C” means “(A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).”

[0077] It is to be understood that the foregoing description is merely illustrative of the disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the disclosure is intended to embrace all such alternatives, modifications and variances. The aspects described with reference to the drawings are presented by way of example only. Other elements, steps, methods and techniques that are utilized in conjunction with those described herein, either directly or indirectly, can also be encompassed by the disclosure.

Claims

1. A catalyst for hydrocarbon pyrolysis, comprising: a waste product pile configured to promote decomposition of the hydrocarbons into hydrogen and carbon; and wherein the waste product is one of the following: Mill scale comprising from 40 to 100% by weight of Fe2O3; or Slag comprising at least one of the following: steel slag comprising 30 to 60% by weight of CaO; Nickel slag comprising 30 to 66% by weight of FeO; or Copper slag comprising 55 to 70% by weight Fe2O3.

2. The catalyst of claim 1, further comprising a substructure layered with the waste product.

3. The catalyst of claim 2, wherein the substructure is made at least in part from the waste product.

4. The catalyst of claim 2, wherein the waste product is enhanced by nickel, cobalt or iron additives.

5. The catalyst of claim 2, wherein the substructure is made at least in part of nickel, cobalt, iron, aluminum oxide, or magnesium oxide. The catalyst according to claim 1 , wherein the waste product pile is crushed into a powder form or a chip form.

7. The catalyst of claim 1, wherein the waste product is slag comprising at least one of steel slag, copper slag, or nickel slag.

8. A method for producing hydrogen and solid carbon, the method comprising: passing hydrocarbons over a spent product catalyst, wherein the spent product catalyst comprises: a waste product pile configured to promote decomposition of the hydrocarbons into hydrogen and carbon; and wherein the waste product is one of the following: Mill scale comprising from 40 to 100% by weight of Fe2O3; or Slag comprising at least one of the following: steel slag comprising 30 to 60% by weight of CaO; Nickel slag comprising 30 to 66% by weight of FeO; or Copper slag comprising 55 to 70% by weight of Fe2O3; heating the hydrocarbon and the spent product catalyst; thermally catalytically decomposing the hydrocarbon into hydrogen and solid carbon; and The hydrogen gas was collected in a container.

9. The method for producing hydrogen and solid carbon according to claim 8, wherein passing the hydrocarbon over the spent product catalyst comprises passing natural gas or methane over the spent product catalyst.

10. The method for producing hydrogen and solid carbon according to claim 8, further comprising collecting the solid carbon deposited on the spent product catalyst.

11. The method for producing hydrogen and solid carbon according to claim 8, wherein passing the hydrocarbons through a spent product catalyst comprises passing the hydrocarbons through a spent product catalytic stack.

12. The method for producing hydrogen and solid carbon according to claim 8, wherein passing the hydrocarbons over a spent product catalyst comprises passing the hydrocarbons over a spent product catalyst comprising at least one of bauxite residue, slag, or mill scale.

13. The method for producing hydrogen and solid carbon according to claim 11, wherein passing the hydrocarbons over the spent product catalyst comprises passing the hydrocarbons over a spent product catalyst comprising: substructure; and A layer of waste product material is applied as an outer layer on the substructure.

14. The method for producing hydrogen and solid carbon according to claim 8, wherein the spent product catalyst is contained in a reactor. 15 . The method for producing hydrogen and solid carbon according to claim 14 , wherein the reactor is a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, a trickle bed reactor, a rotating bed reactor or a slurry reactor.

16. The method for producing hydrogen and solid carbon according to claim 8, further comprising the step of processing the spent product catalyst into a powder or chip form.

17. The method for producing hydrogen and solid carbon according to claim 8, wherein the hydrocarbon and spent product catalyst are heated to 750°C to 950°C.

18. The method for producing hydrogen and solid carbon according to claim 8, wherein the hydrocarbon and spent product catalyst are heated to 500°C to 1300°C.

19. The method for producing hydrogen and solid carbon according to claim 8, wherein passing the hydrocarbons over a spent product catalyst comprises passing the hydrocarbons over a spent product catalyst comprising at least one of steel slag, copper slag, or nickel slag.

20. The method for producing hydrogen and solid carbon according to claim 11, wherein the slag is at least one of steel slag, copper slag, or nickel slag.

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