AND/OR AMMONIA PRODUCTION

FIELD OF INVENTION

[0001] The present invention relates to methods for producing hydrogen for use in methanol and/or ammonia production, and systems using the methods thereof. In particular, the present invention relates to methods, apparatus and systems for producing methanol by recovering methane, producing CO and H2, and hydrogenating CO with H2 to produce methanol and/or ammonia, such that carbon dioxide for various steps is supplied, in part, from one or more external sources.

BACKGROUND OF THE INVENTION

[0002] Methanol is a critical basic chemical which is used to produce other chemical products, such as formaldehyde, polyethylene, polypropylene, acetic acid and plastics, as well as a fuel for vehicles, ships, industrial boilers and cooking, whether as pure methanol, methanol blended with gasoline, or as an ingredient used to produce biodiesel. Methanol may also be converted to methyl tert-butyl ether (MTBE) and dimethyl ether (DME). More than 95% of methanol is currently produced from steam methane reforming (SMR) of natural gas or coal for H2 production, along with CO and CO2 as contributors of “syngas” in a three-step process:

Steam reforming: CH4 + H2O CO + 3H2 AH ⁰ = +214.5 kJ/mol (endothermic)

Water-gas shift reaction (WGSR): CO + H2O CO2 + H2 AH ⁰ = -41.5 kJ/mol (exothermic)

Gas purification: CO2 removal

Overall: CH4 + 2H2O CO2 + 4H2 AH ⁰ = +173.0 kJ/mol (endothermic)

[0003] SMR typically generates 10 MT CO2 per MT ofH2 production. Carbon monoxide is subsequently subjected to hydrogenation to produce methanol plus water with a dissolved organic phase:

CO + H2 -> CH3OH + H2O AH ⁰ = -90.5 kJ/mol (exothermic)

[0004] The resulting methanol solution is subj ected to distillation to recover wastewater plus commercial grade methanol.

[0005] Modem societies are critically dependent on energy derived from fossil fuels to maintain their standard of living. However, it is well known that fossil fuels are a finite resource and are highly polluting. For example, the International Energy Agency (TEA) estimated that global energy-related CO2 emissions were around 33 gigatonnes (Gt) in 2019.

[0006] Reduction of CO2 emissions along hydrocarbon extract! on-to-combustion energy vectors requires that CO2 produced from the combustion of hydrocarbons be avoided through replacement of fossil fuels in power generation pathways with renewable fuels which do not emit CO2 emissions, that emitted CO2 be stored in underground cavities, or that CO2 emissions be physiochemically or biologically converted into synthetic liquid carrier fuels (LCFs) which do not emit CO2.

[0007] Hydrogen fuel offers the potential to greatly reduce dependence on conventional fossil fuels. Hydrogen is the most ubiquitous element in the universe and, in addition to being widely available, is also a clean, non-CCh generating fuel source. Combustion of hydrogen produces water as a by-product, thus avoiding the unwanted generation of the carbon- and nitrogen-based greenhouse gases that are responsible for global warming as well as the unwanted production of soot and other carbon based pollutants.

[0008] The realization of hydrogen as a fuel source ultimately depends on its economic feasibility. Economically viable methods for producing hydrogen as well as efficient means for storing, transferring, and consuming hydrogen are needed.

[0009] Ammonia, a carrier for H2, is used in stationary and mobile fuel cells to produce CCh-free energy, and may be transported to power stations before being reverted back to nitrogen (N2) plus water (H2O) upon combustion.

[0010] The manufacture of ammonia is well-established with a global production of 1980 million metric tonnes reported in 2015, owing primarily to its vast use as a fertilizer as well as precursor for chemical synthesis and industrial refrigerants. Currently, large scale production is primarily carried out via the Haber-Bosch process:

3H ₂ + N2 (g) 2NH ₃ (g) AH ⁰ = - 92 kJ/mol

[0011] This reaction is favourable at room temperature with a Gibbs free energy of -32.9 kJ/mol N2.

[0012] Steam methane reformation (SMR) and the electrochemical generation of hydrogen from water through electrolysis are two common strategies currently used for producing hydrogen. Electrolysis of water, a CCh-free alternative to SMR-produced H2, is not yet economically competitive with SMR, and is currently limited to demonstration plant operations. SMR currently accounts for 95% of all H2 production, typically generating 2 MT of CO2 per MT of H2 generation.

[0013] Current hydrogen production strategies suffer from drawbacks that limit their practical application and/or cost effectiveness. Steam methane reformation reactions are endothermic at room temperature and generally require temperatures of several hundred degrees to achieve acceptable reaction rates. These temperatures are costly to provide, require specialized materials to construct the reactors, and limit the range of applications. Steam reformation also leads to the production of the undesirable greenhouse gases CO2 and/or CO as by-products.

[0014] Water electrolysis has not been widely used in practice because of the high electrical energy costs that are required. The water electrolysis reaction requires a high minimum voltage to initiate and an even higher voltage to achieve practical rates of hydrogen production. Hydrogen produced by the electrolysis of water consumes as much energy as it produces, limiting its widespread adoption. Further, electrolyser technology has high capital costs which further restrict industrial scale applications.

[0015] Methods for production of hydrogen from organic matter also exist. In some methods, hydrogen is produced by pyrolysis of biomass followed by gasification to hydrogen. In some methods, ethanol is distilled from fermented biomass and then reformed to hydrogen. However, some drawbacks to these methods are that CO2 and/or CO are produced as by-products and usable carbon components obtained from biomass are lost. Furthermore, the conditions required for these methods are costly and require energy input.

[0016] Thus, there remains a need for further methods of producing hydrogen for use in methanol and/or ammonia production without generation of CO2 emissions.

SUMMARY OF THE INVENTION

[0017] The present invention provides methods, apparatus and systems for producing hydrogen for use in methanol and/or ammonia production. The methods and systems of the invention are CO2 negative (i.e. CO2 is added to the methods and systems of the invention from external sources as all CO2 produced in the methods is less than the CO2 required for the various steps of the methods), and the methods and systems do not require energy from external sources. The methanol produced by the methods and systems can be collected for external use, e.g. as a transit fuel. Excess energy generated by the methods and systems can be recovered and used for external uses, for example, in industrial processes such as oil refining and steel manufacture. The excess energy is CCh-neutral energy. Excess energy, hydrogen, solid carbon, ammonia, and derivatives thereof may also be collected if desired.

[0018] Various aspects of the present invention provide methods, systems and apparatus for generating hydrogen, methanol, transit fuels, thermal and electrical energy and ammonia.

[0019] In various aspects, the present invention provides a method for producing methanol, the method comprising: (a) gasification of solid carbon with catalytic steam and CO2 to produce a first syngas rich in CO and H2; (b) methanation of CO2 with H2 from the first syngas to produce water and CEE; (c) partial oxidation of CEE from step (b) to produce a second syngas rich in CO and EE; (d) hydrogenation of CO from the first syngas and the second syngas with EE from the first syngas and the second syngas to produce methanol, wherein the energy required for step (a) is provided by: step (b), step (c), step (d), and/or (e) combustion of a portion of the CEE from step (b) with air and/or O2, wherein the combustion products comprise CO2 and water, and wherein the CO2 for steps (a) and (b) is from the first syngas, the second syngas, step (e) and/or one or more external sources. In various embodiments, the method further comprises oxidation of excess CO to CO2, wherein the CO2 is for use in steps (a) and (b). In various embodiments, the method further comprises distillation of the CEE from step (b). In various embodiments, each of the CO and EE are separated from the first syngas and the second syngas by pressure swing adsorption (PSA). In various embodiments, the method does not include step (f). In various embodiments, the CO2 for step (a) and step (b) is from the first syngas, the second syngas and the one or more external sources.

[0020] In various aspects, the present invention also provides a method for producing methanol, the method comprising (a) recovering methane from conventional natural gas and/or renewable natural gas; (b) pyrolyzing methane from step (a) to produce EE and a solid carbon; (c) producing CO by: (i) gasifying the first solid carbon from step (b) with catalytic steam and CO2 to produce: (i) a first syngas rich in CO and EE and comprising unreacted CO2, and (ii) a solid carbon catalyst, wherein the solid carbon catalyst is for use as a catalyst for step (b), (ii) dry methane reforming of CEE from step (a) and CO2 to produce a second syngas comprising CO, EE and CO2, and/or (iii) partially oxidizing methane from step (a) to produce a third syngas comprising CO and EE and comprising unreacted CEE; and (d) hydrogenating CO from step (c) with EE from step (b) and/or step (c) to produce methanol, wherein the energy required for step (b), step (c)(i) and step (c)(ii) is provided by: step (c)(iii), step (d), (e) combustion of a portion of the CEE from step (a) with air and/or O2, wherein the combustion products comprise CO2 and water, and/or (f) methanation of CO2 with EE from step (b) and/or step (c) to produce CEE and water (also referred to as the Sabatier Reaction), wherein the CH4 is for use in step (b), step (c)(ii), step (c)(iii) and/or step (e); and wherein the CO2 for step (c)(i) and step (f) is from the first syngas, the second syngas, the third syngas, step (e) and/or one or more external sources.

[0021] In various embodiments, water from step (f) is recycled as steam to step (c)(i).

[0022] In various embodiments, the CO2 is from the first syngas, the second syngas, the third syngas, step (e) and the one or more external sources. In other embodiments, the CO2 for step (c)(i) and step (f) is from the first syngas, the second syngas, the third syngas and the one or more external sources.

[0023] In various embodiments, the method further comprises oxidation of excess CO to CO2, wherein the CO2 is for use in step (c)(i) and step (f).

[0024] In various embodiments, the method further comprises distillation of the CH4 from step (f).

[0025] In various embodiments, each of the CO and H2 are separated from the first syngas and the second syngas by pressure swing adsorption (PSA).

[0026] In various embodiments, step (b), step (c)(i), step (c)(ii) and step (f) are carried out in a fluidized bed reactor.

[0027] In various embodiments, the method produces excess H2. The H2 produced by the method may be in excess of input requirements for the method.

[0028] In various embodiments, step (c) consists of step (c)(i), step (c)(ii) and step (c)(iii).

[0029] In various embodiments, the method does not comprise step (e).

[0030] In various embodiments, the methane of step (a) is recovered from conventional natural gas and/or renewable natural gas by pressure swing adsorption (PSA).

[0031] In various embodiments, the method further comprises (g) hydrogenating N2 with H2 from step (b) and/or step (c) to produce ammonia in the presence of a catalyst and/or a catalytic support media. The energy for step (g) may be provided by step (c)(iii), step (d), step (e) and/or step (f). In various embodiments, step (g) does not produce CO2.

[0032] In various embodiments, the energy for PSA is provided by step (c)(iii), step (d), step (e) and/or step (f).

[0033] In various embodiments, excess energy from step (c)(iii), step (d), step (e) and/or step (f) is recovered. For example, the recovered excess energy may be in the form of thermal and/or electrical energy. [0034] In various embodiments, a catalyst for step (c)(i), step (d) and/or step (f) comprises one or more transition metals. For example, the one or more transitional metals may comprise nickel.

[0035] In various embodiments, a catalyst for step (c)(ii) comprises a transitional metal embedded in carbon black or activated carbon. For example, the transition metal may comprise nickel.

[0036] In various embodiments, the method is energy balanced.

[0037] In various embodiments, step (d) does not produce CO2.

[0038] In addition to the aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:

[0040] Figure 1 shows a flow diagram of a method or system in accordance with a first embodiment of the present invention.

[0041] Figure 2 shows an energy balance for a method or system in accordance with the first embodiment of the invention.

[0042] Figure 3 shows a material balance for a method or system in accordance with the first embodiment of the invention.

[0043] Figure 4 shows a flow diagram of a method or system in accordance with a second embodiment of the invention. “TMC” refers to transition metal catalyst, “MSW” refers to municipal solid waste, and “PSA” refers to pressure swing adsorption.

[0044] Figure 5 shows an energy balance for a method or system in accordance with the second embodiment of the invention.

[0045] Figure 6 shows a material balance for a method or system in accordance with the second embodiment of the invention.

[0046] Figure 7 shows a fluidized bed reactor for methane pyrolysis according to an embodiment of the invention.

[0047] Figure 8 shows a fluidized bed reactor for gasification of solid carbon with compressed and preheated catalytic steam and carbon dioxide according to an embodiment of the invention. [0048] Figure 9 shows a fluidized bed reactor for dry methane reforming of methane and carbon dioxide according to an embodiment of the invention.

[0049] Figure 10 shows a fluidized bed reactor for carbon dioxide methanation with Fb according to an embodiment of the invention.

DETAILED DESCRIPTION

[0050] In the context of the present disclosure, various terms are used in accordance with what is understood to be the ordinary meaning of those terms.

[0051] Disclosed embodiments include systems, apparatus and methods associated with producing hydrogen for use in methanol and/or ammonia production. Further embodiments also result in generation of transit fuels, solid carbon products (amorphous, crystalline or other forms), hydrogen and ammonia. In various embodiments, the disclosed methods, apparatus and systems produce methanol without the requirement of water to produce H2 through steam methane reforming (SMR) as a constituent of syngas (CO, CO2 and H2), or water-gas shift reaction of carbon monoxide and water vapour to form carbon dioxide and hydrogen. The reduced requirement to use water to produce H2 and CO results in: 1) the elimination of water treatment requirements following the processing of natural gas in water through SMR, and 2) reduced requirement for distillation of methanol to remove water.

[0052] In various embodiments, the methods, systems and apparatus as described herein replace steam methane reforming as used in 95% of current methanol production with a “dry” method of production. For example, hydrogen from methane pyrolysis, solid carbon gasification, partial oxidation of methane and/or dry methane reforming, may be used in the methanol production processes as described herein. In further embodiments, methanol may be produced without co-producing CO2, and without requirements for water treatment and with minimal water distillation. In various embodiments, methanol of at least 99% purity, for example 99.9% purity, may be produced (if a minor CO2 input is added to the carbon monoxide hydrogenation which in turn may increase the required water distillation).

[0053] Referring to Figure 1, and according to a first embodiment of the invention, a method for producing hydrogen for use in methanol and/or ammonia production is shown.

[0054] Pyrolyzed solid carbon (also referred to as char, which comprises pyrolyzed organic carbon) is gasified (1) with pre-heated and compresses, namely catalytic steam and CO2, to produce a first syngas rich in CO and H2 (referred to as Syngas I in Figure 1). The next step is a methanation reaction of CO2 with H2 from the gasification reaction to produce water and CH4, also referred to as the Sabatier Reaction (2), and described in more detail below. The CH4 from this step undergoes partial oxidation (3) to produce a second syngas rich in CO and H2 (referred to as Syngas II in Figure 1). The CO and H2 from the first syngas and the second syngas may be separated from the first syngas and the second syngas, respectively, by pressure swing adsorption (PSA). To produce methanol, CO from the first syngas and the second syngas are hydrogenated with H2 from the first syngas and the second syngas (4). This step may require a minor CO2 input, which is provided by the other steps of the method and/or an external source, as described in more detail below. In various embodiments, the method further comprises distillation of the CP from the carbon dioxide methanation step (2).

[0055] The energy required for the endothermic gasification step (1) is provided by the exothermic CO2 methanation step (2), partial methane oxidation step (3), and/or carbon monoxide hydrogenation step (4). Further energy may be obtained from combustion of a portion of the methane from the CO2 methanation step in air and/or O2, wherein the combustion products include CO2 and water. Methane may also be obtained from natural gas or biogas.

[0056] Thus, CO2 is used in the production of CO and CP , which in turn are used in the production of hydrogen, methanol and ammonia. Hydrogen, methanol and ammonia are produced without generation of excess CO2.

[0057] In various embodiments, all of the unreacted CO2 and CO2 produced by the methods described herein is pooled with additional CO2 obtained from one or more external sources. Thus, the CO2 for the char gasification (1) and carbon dioxide methanation (2) steps is provided from the byproducts and unreacted CO2 of the char gasification step (1), the partial methane oxidation step (3), the combustion of methane (if being employed), and from the one or more external sources. In various embodiments, the majority of the CO2 input to the char gasification step (1) and the carbon dioxide methanation step (2) is from the one or more external sources. Thus, the methods as described herein may consume CO2 produced by other industrial processes. Any excess CO that is not consumed by the carbon monoxide hydrogenation step (4) may be converted to CO2 for use in the method, through PtO2 catalyzed oxidation with air. An energy balance for this aspect of the invention is shown in Figure 2. As can be seen from Figure 2, the method may produce excess energy, before considering energy required for gas compression and PSA separations. In various embodiments, energy for PSA is also provided by the exothermic steps of the method (the CO2 methanation step (2), the partial methane oxidation step (3), and/or the carbon monoxide hydrogenation step (4)). The oxidation of CO and regeneration of its catalyst, PtO2, are both exothermic, contributing to the overall energy surplus of the methods, before considering energy required for gas compression and PSA separations. A material balance for this aspect of the invention is shown in Figure 3. The method may further comprise hydrogenation of N2 with H2 from the first syngas and the second syngas to produce ammonia, as described in more detail below.

[0058] Referring to Figure 4, and according to a second embodiment of the invention, a method for producing hydrogen for use in methanol and/or ammonia production is shown.

[0059] Methane is recovered from conventional natural gas (CNG) and/or renewable natural gas (RNG) (5). In various embodiments, the RNG may be produced from the bioprocessing of organic plant and/or animal matter. In various embodiments, the methane is isolated and purified through pressure swing adsorption (PSA).

[0060] The methane may then pyrolyzed to produce solid carbon and H2 (6). The pyrolysis is an endothermic process which is conducted using heat and power recovered from exothermic steps in the method, as described below. In various embodiments, the methane is fed into the bottom of a high temperature reactor. Solid carbon may then be siphoned off. The energy requirement per mole of H2 produced (37.8 kJ/mol H2) is lower than for SMR-based H2 production. Resulting solid carbon (also referred to as carbon black or char) is used to catalyze the thermal decomposition or pyrolysis of methane. The reaction is slightly endothermic, requiring less than 10% of the heat of methane combustion. The process produces hydrogen and 0.05 m ³ solid carbon/m ³ of H2 if powered by H2, consuming approximately 14% of H2 production. The solid carbon or char for the methane pyrolysis may also be obtained by pyrolyzing solid organic carbon waster under anaerobic conditions, which may produce a catalytic solid carbon, also referred to as catalytic char is Figure 4. The solid organic carbon waste may be from municipal solid waste.

[0061] Solid carbon-catalyzed pyrolysis of methane occurs at 900-l,000°C with a residence time of 1-5 seconds. Activity of solid carbon is characterized by two parameters: (i) initial methane conversion rate (mmole/min-g (K _m °); and (ii) ratio of methane decomposition after one hour (Km ¹ ) relative to the initial methane conversion rate (Km'/Km ⁰ ).

[0062] Pyrolysis of methane is a one-step process and, unlike SMR-based H2 production, does not require WGSR, CO2 removal, oxygen production, steam generation and excess steam removal (drying).

[0063] Solid carbon-catalyzed methane pyrolysis, slowly declining after 6-9 hours, produces H2 and solid carbon with small amounts of C2-3 carbons, such as propane (for example, 0.3 volume %) in effluent gas during the entire process. The amount of solid carbon produced corresponds to the volume of H2 with a 5% margin of error. At sufficiently high temperatures, greater than 900°C, and residence times, 1-5 seconds, the concentration of H2 in the effluent gas, indicating the high catalytic activity of solid carbon. Below 650°C, the methane conversion rate is negligible. The effect of methane space velocity on the initial concentration of H2 in the effluent gas produced by methane degradation over solid carbon.

[0064] The effluent gas produced from the pyrolysis of methane typically comprises 40-50% hydrogen on a volume basis with the balance being unconverted methane. In various embodiments, the unconverted CH4 may be recycled back into the process and/or used in the dry methane reforming of step (c)(ii).

[0065] Methane pyrolysis is a viable alternative for CCh-free hydrogen production, thermally decomposing to form hydrogen and solid carbon. The decomposition of methane is energetically much more economical than water electrolysis, requiring only 75 kJ/mol H2 compared to 286 kJ/mol. Methane pyrolysis proceeds by way of the following reactions. First, methane chemisorption occurs on the catalyst surface and the chemisorbed CH ₄ dissociates into a methyl radical (CH3*) and a hydrogen atom (H*): 440 mJ/mol CH ₄

[0066] Stepwise dissociation reactions ultimately result in elemental carbon and hydrogen: 462 mJ/mol CH ₄ ; 462 mJ/mol CH ₄ ;

[0067] Aggregation of atomic hydrogen into molecular hydrogen:

2H* A H2

[0068] The vapor-liquid-solid (VLS) model (Baker, R.T.K. et al: Journal of Catalysis (1972), 26 (1) pp. 51-62) proposes the growth of carbon nanofibers from a carbon precursor over solid catalysts. This model was initially developed to explain the growth of silicon whiskers. The VLS model consists of three steps: 1) carbon precursor (hydrocarbon) absorbs di-elemental carbon on the catalytic surface, 2) carbon atoms dissolve into the bulk of the catalyst particles, and 3) the solid carbon precipitates at the backside of the catalyst particles and nanostructures.

[0069] VLS mechanism has good agreement with the apparent activation energy obtained for the growth of carbon nanofibers over metal catalysts (Fe, Ni, Co). This mechanism considers carbon diffusion through the bulk of the catalyst as the rate-limiting step for carbon nanofilament development.

[0070] Different types of reactors (packed-bed reactors, fluidized-bed reactors, fluid wall reactors, spouted-bed reactors, honeycomb monoliths, molten salt reactors) have been tested in the catalytic decomposition of methane (Muradov et al. J. Hydrogen Energy (2001), 26 (11), pp. 1165-75). Among them, fluidized-bed reactors and packed-bed reactors, are the most commonly employed. The drawback of packed-bed reactors is the filling of the reactor with solid carbon, eventually blocking the reactant gas flow. To avoid such a problem, carbon must be periodically removed (Abbas, Hazzim F. et al: J. Hydrogen Energy (2010), 35 (3) pp. 1160 - 1190).

[0071] Muradov (Muradov, N., Florida Solar Energy Center: “Thermocatalytic CCh-free Production of Hydrogen from Hydrocarbon Fuels”, Proceedings of the 2000 Hydrogen Program Review (NREL/CP- 570-28890, National Renewable Energy Laboratory, Golden, CO 2000) pp. 70-90) developed several reactor configurations with continuous carbon removal; concluding that fluidized-bed reactors are the most promising for large-scale operation. Methane pyrolysis is industrially implemented using a continuous fluidized-bed catalytic reactor, similar to those used in fluid coking or fluid catalytic cracking and as shown in Figure 7. Fluidized-bed reactors allow continuous addition of fresh catalyst and removal of spent catalyst and carbon deposits. Although the resulting carbon by-product increases the average particle size of the catalyst, the pressure drop in the reactor does not rise significantly; plugging prevented through constant removal of the catalyst. Fluidized-bed reactors also enable high temperatures to be largely avoided (Zhang Jianbo et al: J. Hydrogen Energy (2017), 42 (31) pp. 19755-19755).

[0072] The solid carbon produced by methane pyrolysis is then subjected to gasification (7) with catalytic steam and CO2 to produce (i) a first syngas rich in CO and H2 and comprising unreacted CO2, and (ii) a solid carbon catalyst, which is for use as described above for methane pyrolysis. Alternatively, or in addition, additional chemical feed char may be added to the reactor (referred to as “CFC” in Figure 4). A transition metal catalyst may also be used. In various embodiments, the gasification step (7) may be carried out in a fluidized bed reactor as shown in Figure 8. The CO2 and steam may be from external sources. This step may also be referred to as char gasification. Char or solid carbon gasification involves two reactions, the Boudouard reaction and the water gas reaction:

Boudouard Reaction: C + CO2 A 2CO AH298K = 172 kJ/mol (endothermic)

Water-Gas Shift Reaction: C + H2O A CO + H2 AH298K = 2.85 kJ/mol (exothermic)

[0073] In the first step of the Boudouard reaction, CO2 dissociates at a carbon-free active site, releasing carbon monoxide and forming a carbon-oxygen surface complex. This reaction being reversible can move in the opposite direction as well, forming a carbon active site and CO2 in the second step. In the third step, the carbon-oxygen complex produces a molecule of CO. At temperatures about 700°C, the reaction spontaneously produces CO due to the large positive entropic term that overpowers the enthalpy term in the Gibbs free energy. Introducing CO2 to this step enhances the reactivity of solid carbon 6-7 times. The second syngas that is produced may contain nearly 80 mol % H2 with a 97% conversion efficiency compared to a 90% efficiency without CO2 addition. The addition of steam may also improve the efficiency of solid carbon gasification.

[0074] Carbon monoxide may also be produced by dry methane reforming of CH4 and CO2 to produce H2 and CO (8) as part of a second syngas. In various embodiments, the methane for dry methane reforming is from step (a) (5) and/or CO2 methanation (step (b)). In various embodiments, the CO2 for dry methane reforming is from an external source and/or recycled from unreacted CO2 from this step or from the first syngas generated by gasification of solid carbon and/or the third syngas generated by partial oxidation of methane. In various embodiments, the dry methane reforming (8) may be carried out in a fluidized bed reactor, as shown in Figure 9. This process may also be catalyzed using a transition metal catalyst or a solid carbon catalyst (also referred to as catalytic char).

[0075] Carbon monoxide may be produced by partial oxidation of methane (9). This reaction is between methane and air to produce a third syngas comprising CO and H2. Each of the CO and H2 may be separated from the third syngas by PSA.

[0076] The generated CO is then used in a hydrogenation reaction with H2 to produce methanol (10). CO and H2 may be catalytically converted to methanol with no water phase. In various embodiments, the CO hydrogenation reaction has a stoichiometric ratio of CO 1.0 : H2 2.0. The CO is from step (c) and/or step (d), and the H2 is from step (b), step (c) and/or step (d). A transition metal catalyst may also be used in this process.

[0077] Kar et al., in “Catalytic Homogenous Hydrogenation of CO to Methanol via Formamide”, report on an amine-assisted route for low temperature homogeneous hydrogenation of CO to methanol which proceeds through the formation of formamide intermediates, initially catalyzed by K3PO4, before being hydrogenated in situ to methanol in the presence of catalysts including Ru.

[0078] Hydrogenation of CO rather than hydrogenation of CO2 avoids or minimizes the production of water with the resulting methanol and therefore, reduces the requirement for distillation to purify methanol.

[0079] In various embodiments, overall methanol production costs, yield, selectivity and turnover numbers (TONs) of CO and H2 achieved by the methods and systems as disclosed herein may be a function of choice of catalysts and support media, as well as temperatures adopted in each step of the production process. [0080] In various embodiments, step (b), step (c)(i), step (c)(ii) and step (f) may use the same thermochemical environment. In various embodiments, these steps may use the same thermochemical environment in a fluidized bed reactor.

[0081] An energy balance for this aspect of the invention is shown in Figure 5. A material balance for this aspect of the invention is shown in Figure 6.

[0082] A number of reaction products of the steps outlined above are used as reactants in other steps such that the methods and systems as described herein are CCh-negative, energy-neutral, CF neutral, and/or Fb-neutral. In various embodiments, the methods may produce hydrogen and/or energy in excess, which may then be used externally to the method, for example, in a fuel cell for transport power, hydrocracking of hydrocarbons in oil refineries, or as a reducing agent in steel manufacture.

[0083] In various embodiments, additional CO2 may need to be added to the method or system from, for example, sources external to the method or system. In other words, the methods and systems as described herein may have a negative CO2 balance and require CO2 inputs. Thus, the methods as described herein may consume CO2 produced by other industrial processes. Carbon dioxide generated in the steps of the method is pooled with carbon dioxide from the one or more external sources. In various jurisdictions, the use of CO2 from external sources may result in the advantageous return of “carbon credits”.

[0084] In various embodiments, the methods as described herein may be energy neutral on the basis that the energy required for step (b), step (c)(i) and step (c)(ii) is provided by step (c)(iii), step (d), (e) combustion of a portion of the CF from step (b) with air and/or O2, wherein the combustion products comprise CO2 and water, and/or (f) methanation of CO2 with H2 from step (b) and/or step (c) (11). The products of this carbon dioxide methanation reaction (11), also referred to as the Sabatier Reaction, are CH4 and water. The CF is consumed in pyrolysis of methane step, the dry methane reforming step, the partial oxidation of methane, and/or the combustion of CF , the latter being limited to only if further energy is required to achieve energy balance (or energy neutrality) for the method. The embodiment shown in Figure 4 does not include the combustion of CF . In various embodiments, the carbon dioxide methanation reaction may be carried out in a fluidized bed reactor, as shown in Figure 10.

[0085] The methods and systems described herein replaces hydrogen produced from steam methane reforming (“SMR-H2”), which is used for over 90% of global H2 production. Over 95% of the methanol produced worldwide currently uses SMR-H2. As compared to this method, the methods and systems described herein generate methanol with minimal requirement for distillation to remove water as needed for SMR-produced methanol. The H2 for use in production of methanol may be obtained from the methane pyrolysis step, the gasification of solid carbon step, and/or the dry methane reforming step.

[0086] It will be appreciated that in practice, the methods and systems described herein which comprise multiple steps and components may be carried out by a number of parties, with a key party overseeing and coordinating the steps. Alternatively, the steps which make up the methods and systems may be carried out by a single party.

[0087] Various products may be isolated from the methods and systems as described herein, in addition to methanol.

[0088] For example, amorphous carbon or crystalline carbon may be recovered and/or prepared from a portion of the solid carbon from step (b) or the solid carbon catalyst from step (c)(i). Commercial products for pyrolysis-produced solid carbon include feed for tire manufacture and/or steel production.

[0089] Ammonia (NH3) is produced from the hydrogenation of air-separated nitrogen, through catalytic conversion with H2 (e.g. direct nitrogen hydrogenation (DNH)) (12). For example, air-extracted and PSA-purified N2 can be used to produce NH3 using an enhanced Haber-Bosch (H-B) process using catalysts which lower temperature and pressure conditions required by conventional H-B process. In various embodiments, N2 may be hydrogenated with H2 from step (b) and/or step (c) to produce ammonia in the presence of a catalyst and/or a catalytic support media.

[0090] Hydrogen produced from methane pyrolysis, solid carbon gasification, dry methane reforming and/or partial oxidation of methane may be used as feed for ammonia (NH3) and H2 fuel cells (AFCs and H2-FCS, respectively) for CCh-free transportation power. NH3 is produced from the catalytic conversion of H2 and N2 separated from air using pressure swing adsorption technology. Hydrogen fuel cells used in air, sea and land transport produce no CO2 emissions, only water (H2-FCS) and water and N2 (AFCs).

[0091] Excess energy may also be recovered from the methods and systems as described herein, and may be in the form of thermal or electrical energy. The recovered excess energy may be used or sold for downstream processes, e.g. industrial processes such as oil refining and steel manufacture.

[0092] Enthalpy changes for the methods and systems described herein versus steam methane reformingbased decomposition of methane contribute to overall advantages in energy balance. SMR is endothermic, requiring thermal input to produce steam to power the thermal decomposition of methane. The methods and systems as described herein also require thermal input for decomposition of methane through pyrolysis to produce solid carbon or carbon black and hydrogen H2, and gasification of the solid carbon. Combined heat and power (“CHP”) generated from hydrogenation of CO as well as energy produced from methanation of CO, combustion of methane and/or oxidation of methane is pooled to meet the energy balance of the methods and systems as described herein. To avoid thermal energy losses, all thermal processes of the methods described herein may share the same thermal environment in order to share thermal energy and minimize thermal losses that result from transfer between different types of reactors.

[0093] As used herein, the term “about” refers to an approximately +/-10% variation from a given value. It is to be understood that such a variation is always included in any given value provided herein, whether or not it is specifically referred to. The use of the word “a” or “an” when used herein in conjunction with the term “comprising” may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one” and “one or more than one.”

[0094] Citation of references herein is not an admission that such references are prior art to the present invention.

[0095] The present invention has been described with regard to one or more embodiments. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. Such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way. Numeric ranges are inclusive of the numbers defining the range. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.