Processes and systems for regenerative separation of hydrogen gas

Abstract

A method and apparatus for regenerative hydrogen separation at high temperatures for production of pure hydrogen gas. Pure metals and metallic alloys are used at high temperatures to maximize the catalytic effect for hydrogen dissociation, hydrogen diffusion and hydrogen sorption capacity. Metallic materials are used that can selectively sorb hydrogen at high temperatures. These materials are integrated into equipment designs and process configurations to process a stream of hot mixed process gases to produce a stream of pure hydrogen product at the desired system temperature. The invention can be used to enhance the performance of existing plants such as steam methane reforming applications by increasing the conversion to hydrogen, eliminating or reducing the number of shift converters, providing pure hydrogen product, and enhancing the overall energy efficiency. In some embodiments, the hydrogen sorption system is built inside a hydrogen production reactor, enhancing the chemical equilibrium inside the reactor, to achieve higher conversion and hydrogen yields.

Description

[0001] PROCESSES AND SYSTEMS FOR REGENERATIVE SEPARATION OF HYDROGEN GAS

[0002] Cross-Reference to Related Application

[0003] This application claims the benefit of United States provisional application No. 63 / 738,176, filed December 23, 2024.

[0004] Field of the Invention

[0005] The invention pertains to processes and apparatuses for the separation of hydrogen gas.

[0006] Background of the Invention

[0007] Hydrogen is an important chemical required for multiple industries including petroleum refining, and processes such as hydrogenation of fats and oils, hydro-cracking, hydrodealkylation, hydrodesulphurization and chemical reduction processes. Hydrogen is a key reactant to produce methanol, ammonia, steel, hydrochloric acid, aniline, synthetic fuels, among other chemicals.

[0008] Hydrogen is an important industrial feedstock, zero-carbon energy carrier and a promising way of decarbonizing hard-to-electrify sectors of the economy. While hydrogen can be produced from electrolysis of water in advanced electrolyzers, the vast majority of the hydrogen produced worldwide is still based on thermochemical processes, particularly steam methane reforming.

[0009] There are several technological challenges to produce high-purity hydrogen using thermochemical reactors with low CO2 footprint. Existing thermochemical solutions to hydrogen production typically produce a mixed stream of process gases that include hydrogen, that needs to be further converted in a series of shift reactors with intermediate cooling that are often limited by chemical equilibrium. Steam methane reforming, for instance, relies oncatalytic reactors in series for high-temperature and low-temperature shift to overcome the chemical equilibrium limits of the hydrogen-containing gas.

[0010] Moreover, the process gas is typically cooled and purified using systems such as pressure swing adsorption (PSA) where the hydrogen passes through and the other components are adsorbed. These systems operate at close to ambient temperature and in thermochemical applications consume large amounts of energy to cool and then re-heat the process gas. This energy penalty is more severe in cases where the intended use of hydrogen requires re-heating, such as hydrodesulphurization and other thermochemical applications. In cases where the reaction occurs at low pressure (e.g. methane pyrolysis), separation often requires pressurization of the feed and / or re-pressurization of the non-hydrogen stream for recycle when conversion per pass is not complete.

[0011] There are also several high-temperature processes in which hydrogen is generated within the reactor as a secondary product and requires further separation. In those processes, different dehydrogenated chemicals are the main product, while hydrogen needs to be removed after production. Examples of such processes include propylene plants (i.e. , propane dehydrogenation), ethylene plants (i.e., steam cracking and / or ethane dehydrogenation), styrene plants, methyl ethyl ketone (MEK) plants, and ammonia cracking. These processes are often limited by the thermodynamic equilibrium and therefore require downstream separation and recycling units to achieve reasonable overall feedstock conversion. High-temperature hydrogen separation, whether performed in situ within a reactor or between reactor stages when using multiple reaction stages, can greatly benefit these processes by shifting the thermodynamic equilibrium (if in situ), enhancing material separation and recovery, and reducing system energy consumption and heat loss.

[0012] Importantly, if hydrogen is selectively removed in a dehydrogenation system, it will shift the equilibrium forward only for the desired dehydrogenation reaction, and reduce the negative effects of undesired reactions involving hydrogen.

[0013] Some prior art technologies have attempted to provide hydrogen separation at elevated temperatures using membranes. However, membrane technologies have not been widely adopted at high temperatures since membranes are prone to deactivation and / or failure at temperatures above about 450°C. The possible failure mechanisms of membranes at high temperature include: pin-hole and manufacturing defects, hydrogen embrittlement,hydrogen swelling, inter-diffusion, formation of oxide layers, thermal stress and thermal cycling failure, poisoning, and fouling. Although newer membranes such as those based on palladium alloys have been proven, they are still limited to a maximum temperature of about 650°C, and have practical limits in industrial applications (e.g., sensitivity to H2S, S, SOx, etc.) and high raw material cost, which requires the membranes to be very thin to achieve the required flux rate at reasonable cost, at which point supports are required in order to withstand the transmembrane pressures needed to achieve the required hydrogen partial pressure driving forces. Technology that can treat gas from industrial sources at temperatures above 600°C would make a substantial difference for hydrogen technologies. Key technological challenges associated with hydrogen separation include:

[0014] • Mature separation technologies such as PSA require cooling of process gas, which is often associated with high energy and operating costs and cannot be used for most in situ hydrogen removal applications.

[0015] • PSA adsorbs the other, non-hydrogen, gas species which requires a pressure decrease to remove, and re-pressurization for recycle in processes with incomplete per-pass conversion.

[0016] • High-temperature hydrogen separation membranes are not a mature technology and membranes applications are still under development in the industry to increase longevity, reduce cost, prevent membrane failure, and enhance separation yield.

[0017] • The materials used for hydrogen separation / membrane applications can be prone to hydrogen attack and hydrogen embrittlement, leading to cracking and failure if conditions change too rapidly and making the robust assemblies required to withstand the transmembrane pressures challenging and costly to achieve.

[0018] • There are currently no high-temperature hydrogen separation technologies that can reliably purify hydrogen at temperatures above 650°C to couple them directly with high-temperature hydrogen production reactors.

[0019] The present invention presents a solution that addresses all the above challenges, while unlocking the potential for highly efficient system integration for ultra-pure hydrogen production. The invention uses high-temperature systems to remove / separate hydrogen atfull reaction temperatures (in situ or ex situ) with high efficiency. This process can be used to enhance the performance of existing plants such as steam methane reforming applications by increasing the conversion to hydrogen, providing pure hydrogen product, and enhancing the overall energy efficiency. Moreover, the invention can unlock technology applications for maximum efficiency and scalability for low greenhouse gas processes such as hydrocarbon / methane pyrolysis, biomass gasification, biogas processing, waste processing, and hydrocarbon steam reforming coupled with carbon capture.

[0020] The invention may also be integrated with other processes in which hydrogen is generated at elevated temperatures as a byproduct, thereby enabling enhanced feedstock conversion, reduced effect of undesired side reactions involving hydrogen, production of high-purity hydrogen, improved separation, reduced feedstock recycle, and / or increased energy efficiency.

[0021] Throughout this description and claims:

[0022] • “Hydrogen-containing gas” refers to a stream of process gas produced from thermochemical or electrochemical methods that contains H2molecules and other species.

[0023] • “Syngas” (synthesis gas) refers to a hydrogen-containing gas with a mixture of hydrogen (H2), carbon monoxide (CO), and sometimes carbon dioxide (CO2).

[0024] Syngas is a key intermediate in the production of various chemicals and fuels.

[0025] • “Steam methane reforming” (SMR) refers to the process to convert natural gas into hydrogen containing gas by using a thermochemical catalytic process.

[0026] • “Chemical equilibrium” refers to a state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal. The conversion to a desirable product will not increase beyond this equilibrium point. To shift forward the chemical equilibrium, the system must be altered by either selectively removing a product, or by changing the reaction temperature and / or pressure.

[0027] • “Shift reactor” refers to the catalytic reactor used to conduct the water-gas shift reaction, where carbon monoxide and water vapor react to form carbon dioxide and hydrogen product.• “Hydrogen separation and purification” refers to a family of processes to increase the concentration of hydrogen. Depending on the nature of the process, and the process conditions, they may be able to achieve high hydrogen purity.

[0028] • “Adsorption” refers to the process where a chemical species adheres to the surface of the adsorber material.

[0029] • “Absorption” refers to the process where a chemical species penetrates deep into the bulk of the absorber material. In this document, the term absorption and absorber are meant to be generic and consider sorption, absorption and adsorption.

[0030] • “Sorb” refers to taking up and holding by either adsorption or absorption or a combination thereof.

[0031] • “Sorbent” means a substance that sorbs.

[0032] • “Sorption” refers to the act of sorbing, including adsorption, absorption and a combination thereof.

[0033] • “Pressure swing adsorption” (PSA) refers to the hydrogen purification process that generally takes place at low temperatures and relies on variation of pressure of an adsorbent in a substrate to remove non-hydrogen species, producing a purified / concentrated hydrogen gas.

[0034] • “Hydrogen permselective membrane” refers a selective barrier that allows only hydrogen to pass through while blocking all other species.

[0035] • “Selectivity” refers to the ability by a material to preferentially separate a chemical species, while blocking others.

[0036] • “Hydrogen embrittlement” refers to the process by which a material gets weaker and susceptible to cracking when exposed to hydrogen gas.

[0037] • “Regenerative absorption of hydrogen” and “regenerative hydrogen separation” refer to the process where an absorber material is used to selectively absorb hydrogen, followed by a desorbing step allowing for repeated use of the absorbent material. • “Metals” is referred to in the broad sense as it includes transition metals, alkali metals, alkaline metal, lanthanide metals, post transition metals and / or their alloys.

[0038] • “Steam methane reforming” refers to the industrial chemical process used to produce hydrogen gas (H2) from methane (CH4) and steam (H2O). It is the most common method of large-scale hydrogen production worldwide.• “Natural gas pyrolysis or methane pyrolysis” refers to the chemical process in which natural gas (mainly methane, CH4) is split into hydrogen (H2) and solid carbon (C).

[0039] • “Dehydrogenation reactions” are chemical reactions in which hydrogen is removed from a molecule, typically converting a saturated compound into an unsaturated one.

[0040] • “Propane dehydrogenation, or PDH” refers to the process in which propane (C3H8) is converted into propylene (C3H6) and hydrogen gas (H2) by dehydrogenation of propane molecules.

[0041] • “Ethylene plants” refers to the industrial production process of ethylene (C2H4) using steam cracking and / or ethane dehydrogenation,

[0042] • “Styrene plants” refers to the dehydrogenation of ethylbenzene (EB) to styrene (C6H5CH=CH2).

[0043] • “Ammonia cracking” refers to the decomposition process in which ammonia gas (NH3) is broken down into hydrogen (H2) and nitrogen (N2) gases.

[0044] Summary of the Invention

[0045] The present inventors have screened a wide variety of pure metals and metal alloys for applications at high-temperature (above about 450°C). The evaluation process considered metal composites and coatings to maximize the catalytic effect for hydrogen dissociation, hydrogen diffusion as well as hydrogen sorption capacity, i.e. , absorption capacity and / or adsorption capacity. The inventors have identified a group of metallic materials that can selectively sorb hydrogen at high temperatures, and have invented a novel way to utilize these materials for high-temperature hydrogen separations and improved overall process performance. These materials are integrated into equipment designs and process configurations to process a stream of hot mixed process gases to produce a stream of gas substantially free of hydrogen, as well as a stream of pure hydrogen product. Moreover, the materials have been found to be active for in situ and ex-situ hydrogen separation in reactor systems to shift the chemical equilibrium forward.

[0046] The invention provides a method and apparatus for regenerative hydrogen separation and production of hydrogen. Key features are a source of hydrogen-containing gas, a regenerable hydrogen sorbent metal material, high-temperature regenerative hydrogensorption and desorbing within the same vessel or in separate vessels, production of a substantially hydrogen-free stream, and production of a substantially pure hydrogen stream product. In some applications, the hydrogen separation allows for enhancement of chemical reactions that produce hydrogen as a main product, as a co-product, or as a byproduct. According to one aspect of the invention there is provided a method of regenerative hydrogen separation in which hydrogen gas is selectively removed from a hydrogencontaining gas comprising the hydrogen gas and other gas species, the method comprising the steps of: (a) contacting a regenerable hydrogen sorbent metallic material with the hydrogen-containing gas, at a first temperature and a first partial pressure of hydrogen; (b) selectively sorbing hydrogen from the hydrogen-containing gas into the regenerable hydrogen sorbent metallic material; (c) producing a gas stream with a reduced level of hydrogen gas; and (d) exposing the regenerable hydrogen sorbent metallic material with sorbed hydrogen to a second temperature and / or a second partial pressure of hydrogen, wherein the second temperature is higher than the first temperature and / or the second partial pressure is lower than the first partial pressure, thereby desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material to produce a stream of purified hydrogen gas.

[0047] According to another aspect of the invention there is provided a method of regenerative hydrogen separation in which hydrogen gas is selectively removed from a hydrogencontaining gas comprising the hydrogen gas and other gas species, the method comprising the steps of: (a) feeding a stream of the hydrogen-containing gas to a process vessel containing a regenerable hydrogen sorbent metallic material; (b) contacting the regenerable hydrogen sorbent metallic material with the hydrogen-containing gas in the process vessel, at a first temperature and a first partial pressure of hydrogen; (c) selectively sorbing hydrogen from the hydrogen-containing gas into the regenerable hydrogen sorbent metallic material; (d) allowing the other gas species to pass through the process vessel, producing a gas stream substantially free of hydrogen gas; and (e) exposing the regenerable hydrogen sorbent metallic material with sorbed hydrogen to a second temperature and a second partial pressure of hydrogen, wherein the second temperature is higher than the first temperature and / or the second partial pressure is lower than the first partial pressure,thereby desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material to produce a stream of purified hydrogen gas from the process vessel.

[0048] According to another aspect of the invention there is provided a method of regenerative hydrogen separation in which hydrogen gas is selectively removed from a hydrogencontaining gas comprising the hydrogen gas and other gas species, the method comprising the steps of: (a) feeding a stream of the hydrogen-containing gas to a sorption vessel containing a regenerable hydrogen sorbent metallic material; (b) contacting the regenerable hydrogen sorbent metallic material with the hydrogen-containing gas in the sorption vessel, at a first temperature and a first partial pressure of hydrogen; (c) selectively sorbing hydrogen from the hydrogen-containing gas into the regenerable hydrogen sorbent metallic material; (d) allowing the other gas species to pass through the sorption vessel, producing a gas stream substantially free of hydrogen gas; and (e) feeding the regenerable hydrogen sorbent metallic material with sorbed hydrogen to a desorbing vessel having a second temperature and a second partial pressure of hydrogen, wherein the second temperature is higher than the first temperature and / or the second partial pressure is lower than the first partial pressure, thereby desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material in the desorbing vessel to produce a stream of purified hydrogen gas from the desorbing vessel.

[0049] According to another aspect of the invention there is provided a method of production of hydrogen gas and regenerative hydrogen separation, in which the hydrogen gas is selectively removed from a hydrogen-containing gas comprising the hydrogen gas and other gas species, the method comprising the steps of: (a) feeding a feedstock for hydrogen production into a hydrogen production and in situ sorption vessel; (b) contacting both a hydrogen production catalyst and a regenerable hydrogen sorbent metallic material with the feedstock in the hydrogen production and sorption vessel; (c) producing a hydrogencontaining gas and simultaneously selectively sorbing the product hydrogen into the regenerable hydrogen sorbent metallic material; (d) allowing the other gas species to pass through the hydrogen production and sorption vessel, producing a gas stream substantially free of hydrogen gas; (e) feeding the regenerable hydrogen sorbent metallic material with sorbed hydrogen to a desorbing vessel; (f) desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material in the desorbing vessel to produce a stream of purifiedhydrogen gas from the desorbing vessel; and (g) feeding the regenerable hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel back to the hydrogen production and sorption vessel.

[0050] According to another aspect of the invention there is provided a method of production of hydrogen gas and regenerative hydrogen separation, in which the hydrogen gas is selectively removed from a hydrogen-containing gas comprising the hydrogen gas and other gas species, the method comprising the steps of: (a) feeding a feedstock for hydrogen production into a process vessel; (b) contacting both a hydrogen production catalyst and a regenerable hydrogen sorbent metallic material with the feedstock in the process vessel; (c) producing a hydrogen-containing gas and simultaneously selectively sorbing the product hydrogen into the regenerable hydrogen sorbent metallic material; (d) allowing other gas species to pass through the process vessel, producing a gas stream substantially free of hydrogen gas; and (f) desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material in the process vessel to produce a stream of purified hydrogen gas from the process vessel. It is understood that this approach can be combined in series with multiple alternating stages of reaction to achieve a similar performance effect as in situ where both the reaction and sorption occur in one vessel.

[0051] Desorption of hydrogen in any of these cases can be enhanced by reducing the partial pressure of hydrogen in contact with the sorption material. This can be achieved through the use of lower pressure, including vacuum, or a diluent such as an inert sweep gas and / or a reactive sweep gas that consumes the hydrogen (e.g., oxygen to form water / steam). According to another aspect of the invention there is provided a method of dehydrogenation of chemicals, the method comprising the steps of: (a) feeding a feedstock dehydrogenation into a process vessel; (b) contacting both a dehydrogenation catalyst and a regenerable hydrogen sorbent metallic material with the feedstock in the process vessel; (c) producing a hydrogen-containing gas and simultaneously selectively sorbing the product hydrogen into the regenerable hydrogen sorbent metallic material; (d) allowing other gas species to pass through the process vessel, producing a gas stream of main dehydrogenated product, substantially free of hydrogen gas; and (f) desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material in the process vessel to produce a stream of purifiedhydrogen gas from the process vessel; (e) further processing of the main dehydrogenated product.

[0052] According to another aspect of the invention there is provided an apparatus for regenerative separation of hydrogen gas from a hydrogen-containing gas that comprises the hydrogen gas and other gas species, the apparatus comprising: (a) a regenerative hydrogen sorbent metallic material, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from the hydrogen-containing gas; (b) means for feeding the hydrogen-containing gas to contact the regenerative hydrogen sorbent metallic material; (c) means for varying the temperature and / or the pressure to which the regenerative hydrogen sorbent metallic material is subject between a first temperature and / or first pressure at which the hydrogen is sorbed into the regenerative hydrogen sorbent metallic material and a second temperature and / or second pressure at which the hydrogen is desorbed from the regenerative hydrogen sorbent metallic material; (d) means for releasing a gas stream with a reduced level of hydrogen gas; and (e) means for releasing a stream of purified hydrogen gas.

[0053] According to another aspect of the invention there is provided an apparatus for regenerative separation of hydrogen gas from a hydrogen-containing gas that comprises the hydrogen gas and other gas species, the apparatus comprising: (a) a process vessel containing a regenerative hydrogen absorbent metallic material, the regenerative hydrogen absorbent metallic material being capable of selectively absorbing hydrogen from the hydrogencontaining gas; (b) means for feeding the hydrogen-containing gas into the process vessel to contact the regenerative hydrogen absorbent metallic material; (c) means for varying the temperature and / or the pressure in the process vessel between a first temperature and / or first pressure at which the hydrogen is absorbed into the regenerative hydrogen absorbent metallic material and a second temperature and / or second pressure at which the hydrogen is desorbed from the regenerative hydrogen absorbent metallic material; (d) means for releasing a gas stream substantially free of hydrogen from the process vessel; and (e) means for releasing a stream of purified hydrogen gas from the process vessel.

[0054] According to another aspect of the invention there is provided an apparatus for regenerative separation of hydrogen gas from a hydrogen-containing gas that comprises hydrogen gas and other gas species, the apparatus comprising: (a) a sorption vessel containing aregenerative hydrogen sorbent metallic material, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from the hydrogen-containing gas; (b) means for feeding the hydrogen-containing gas into the sorption vessel to contact the regenerative hydrogen sorbent metallic material; (c) a desorbing vessel operatively connected to the sorption vessel; (d) means to control the temperature and pressure in the sorption vessel for the sorption of hydrogen into the regenerative hydrogen sorbent metallic material; (e) means for moving the regenerative hydrogen sorbent metallic material with sorbed hydrogen from the sorption vessel to the desorbing vessel; (f) means to control the temperature and pressure in the desorbing vessel for the desorbing of hydrogen from the regenerative hydrogen sorbent metallic material; (g) means for moving the regenerative hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel to the sorption vessel; (h) means for releasing a gas stream substantially free of hydrogen from the sorption vessel; and (i) means for releasing a stream of purified hydrogen gas from the desorbing vessel.

[0055] According to another aspect of the invention there is provided an apparatus for the production of hydrogen gas and regenerative separation of hydrogen gas from a hydrogencontaining gas that comprises hydrogen gas and other gas species, the apparatus comprising: (a) a hydrogen production and sorption vessel; (b) a hydrogen production catalyst within the hydrogen production and sorption vessel; (c) a regenerative hydrogen sorbent metallic material within the hydrogen production and sorption vessel, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from the hydrogen-containing gas; (d) means for feeding a feedstock for hydrogen production into the hydrogen production and sorption vessel to contact the hydrogen production catalyst and the regenerative hydrogen sorbent metallic material; (e) a desorbing vessel operatively connected to the hydrogen production and sorption vessel; (g) means for moving the regenerative hydrogen sorbent metallic material with sorbed hydrogen form the hydrogen production and sorption vessel to the desorbing vessel; (h) means for releasing a gas stream substantially free of hydrogen from the hydrogen production and sorption vessel; (i) means for releasing a stream of purified hydrogen gas from the desorbing vessel; (j) means for controlling the temperature and pressure in the hydrogen production and sorption vessel for the production of hydrogen and the sorption of hydrogen; (k) means for controlling the temperature and pressure in the desorbing vessel for the desorbing ofhydrogen from the regenerative hydrogen sorbent metallic material in the desorbing vessel; and (I) means for feeding the regenerative hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel back to the hydrogen production and sorption vessel. According to another aspect of the invention there is provided an apparatus for the production of hydrogen gas and regenerative separation of hydrogen gas from a hydrogencontaining gas that comprises hydrogen gas and other gas species, the apparatus comprising: (a) a process vessel; (b) a hydrogen production catalyst within the process vessel; (c) a regenerative hydrogen sorbent metallic material within the process vessel, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from a hydrogen-containing gas; (d) means for feeding a feedstock for hydrogen production into the process vessel to contact the hydrogen production catalyst and the regenerative hydrogen sorbent metallic material; (e) means for releasing a gas stream substantially free of hydrogen from the process vessel; (f) means for controlling the temperature and pressure in the process vessel for the generation of hydrogen gas, the sorption of hydrogen into the regenerative hydrogen absorbent metallic material, and the desorbing of sorbed hydrogen from the regenerative hydrogen sorbent metallic material; and (g) means for releasing a stream of purified hydrogen gas from the process vessel. According to another aspect of the invention there is provided an apparatus for the dehydrogenation of chemicals, the apparatus comprising: (a) a process vessel; (b) a dehydrogenation catalyst within the process vessel; (c) a regenerative hydrogen sorbent metallic material within the process vessel, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from a hydrogen-containing gas; (d) means for feeding a chemical feedstock into the process vessel to contact the dehydrogenation catalyst and the regenerative hydrogen sorbent metallic material; (e) means for releasing a gas stream substantially free of hydrogen from the process vessel; (f) means for controlling the temperature and pressure in the process vessel for the generation of hydrogen gas, the sorption of hydrogen into the regenerative hydrogen sorbent metallic material, and the desorbing of sorbed hydrogen from the regenerative hydrogen sorbent metallic material; (g) means for releasing a stream of purified hydrogen gas from the process vessel; and (f) means for further processing of the main product dehydrogenated chemical.According to another aspect of the invention there is provided an apparatus for the dehydrogenation of chemicals, the apparatus comprising: (a) multiple process vessels; (b) a dehydrogenation catalyst within alternating process vessels; (c) a regenerative hydrogen sorbent metallic material following each reaction process vessel, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from a hydrogencontaining gas; (d) means for feeding a chemical feedstock into their respective process vessels to contact the dehydrogenation catalyst and the regenerative hydrogen sorbent metallic material; (e) means for releasing a gas stream substantially free of hydrogen from the process vessel; (f) means for controlling the temperature and pressure in the process vessel for the generation of hydrogen gas, the sorption of hydrogen into the regenerative hydrogen sorbent metallic material, and the desorbing of sorbed hydrogen from the regenerative hydrogen sorbent metallic material; (g) means for releasing a stream of purified hydrogen gas from the process vessels containing sorbent; and (f) means for further processing of the main product dehydrogenated chemical.

[0056] Further aspects and example embodiments are illustrated in the accompanying drawings and described in the following description.

[0057] Brief Description of the Drawings

[0058] Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

[0059] Figure 1 is an example process flow diagram illustrating a basic embodiment of the invention where the hydrogen sorption and desorbing take place in the same vessel.

[0060] Figure 2 is an example process flow diagram illustrating a basic embodiment of the invention where the hydrogen sorption and desorbing take place in different vessels and the regenerable material is used as a carrier.

[0061] Figure 3 provides experimental data for the absorption of hydrogen in an embodiment of the invention where the regenerable hydrogen sorbent metallic material is tantalum operating at 550°C and 1 bar(a).Figure 4 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable hydrogen sorbent metallic material is tantalum operating at 550°C and 1 bar(a). The initial cycle was performed when the material surface was oxidized, which showed slower kinetics in the first cycle.

[0062] Figure 5 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable hydrogen sorbent metallic material is tantalum operating at temperatures in the range of 400°C to 600°C.

[0063] Figure 6 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable hydrogen sorbent metallic material is titanium Grade 2 operating at 700°C.

[0064] Figure 7 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable hydrogen sorbent metallic material is titanium Grade 2 mesh operating at 700°C and 1 bar(a).

[0065] Figure 8 provides experimental data for the sorption of hydrogen where the regenerable hydrogen sorbent metallic material is titanium of various grades operating at 700°C and 1 bar(a).

[0066] Figure 9 provides experimental data for the sorption of hydrogen where the regenerable hydrogen sorbent metallic material is Ta with Pd coating.

[0067] Figure 10 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is titanium G2 mesh used for sorption / desorption.

[0068] Figure 11 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is titanium G2 particles used for sorption / desorption. Figure 12 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is Pd before (left) and after (right) sorption desorption cycles.

[0069] Figure 13 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is Ta before (left) and after (right) sorption desorption cycles.Figure 14 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is V before (left) and after (right) sorption desorption cycles.

[0070] Figure 15 provides SEM images for an embodiment of the invention where the regenerable hydrogen sorbent metallic material is Zr before (left) and after (right) sorption desorption cycles.

[0071] Figure 16 is an example process flow diagram of an embodiment of the invention using regenerable hydrogen sorbent metallic material contained in two vessels and the material is kept inside each vessel.

[0072] Figure 17 is an example process flow diagram of an embodiment of the invention using regenerable hydrogen sorbent metallic material contained in two vessels and the material is circulated between the vessels as a hydrogen carrier.

[0073] Figure 18 is an example process flow diagram of an embodiment of the invention where the system is integrated into a thermochemical hydrogen production process.

[0074] Figure 19 is an example process flow diagram of an embodiment of the invention where the system is integrated into a steam methane reforming production process.

[0075] Figure 20 is an example process flow diagram of an embodiment of the invention where the sorption process is conducted in situ as the hydrogen is produced using circulating sorption material.

[0076] Figure 21 is an example process flow diagram of an embodiment of the invention where the sorption process is conducted in situ as the hydrogen is produced in fixed bed reactors with gas switching.

[0077] Figure 22 provides an alternative embodiment of the invention, wherein the hydrogen sorption process is conducted in situ within a dehydrogenation plant, with catalyst reactivation and sorbent regeneration carried out within the same reactor vessel.

[0078] Figure 23 provides an alternative embodiment of the invention, wherein the hydrogen sorption process is conducted in situ within a dehydrogenation plant, with the catalyst reactivation and sorbent regeneration carried out in separate reactor vessels.Figure 24 shows an alternative embodiment of the invention where a conventional propane dehydrogenation (PDH) plant is equipped with an in situ hydrogen removal system thereby enhancing the performance of the plant.

[0079] Detailed Description of the Invention

[0080] Throughout the following description, specific details are set forth to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. Well known aspects of the technology practiced in industry have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive sense.

[0081] The present invention provides process and apparatus for regenerative hydrogen separation at high temperatures for production of pure hydrogen gas.

[0082] Referring to Figure 1, in one embodiment the apparatus of the invention is a regenerative hydrogen sorber / desorber system 10. The system 10 comprises a sorption / desorbing vessel 100 which contains a regenerable hydrogen sorbent metallic material 101. The feedstock to the process system is a source of hydrogen-containing gas 1. The regenerable hydrogen sorbent metallic material 101 selectively sorbs hydrogen gas into the bulk of the material, while allowing the other species to pass through. The gas that was not sorbed leaves the system as a gas stream 2 having a reduced level of hydrogen gas, e.g., substantially free of hydrogen gas. The regenerable hydrogen sorbent metallic material 101 holds the hydrogen until a regeneration cycle is activated, where the operating conditions are changed (namely, the temperature is increased or the partial pressure of hydrogen is decreased). During regeneration, a stream of purified hydrogen gas, i.e., substantially pure hydrogen gas 3, is produced as the product. This embodiment is most suitable for batch operation.

[0083] Referring to Figure 2, in another embodiment the apparatus of the invention is a regenerative hydrogen sorber / desorber system 10 comprising a sorption vessel 102, which contains a regenerable hydrogen sorbent metallic material 101, and a desorbing vessel103. The feedstock to the process system is a source of hydrogen-containing gas 1. The regenerable hydrogen sorbent metallic material 101 selectively sorbs hydrogen gas into the bulk of the material, while allowing the other species to pass through. The gas that was not sorbed leaves the system as a gas stream 2 substantially free of hydrogen gas. The regenerable hydrogen sorbent metallic material 101 holds the hydrogen and is used as a hydrogen carrier to move hydrogen between vessels 102 and 103. The temperature of the desorbing vessel 103 is equal to or higher than that of the sorption vessel 102. The partial pressure of hydrogen in the desorbing vessel 103 is equal to or lower than that of the sorption vessel 102. A stream of substantially pure hydrogen gas 3 is produced as the product. This embodiment is suitable for continuous, semi-continuous or batch operation. The determination of materials suitable for use as a regenerable hydrogen sorbent metallic material 101 in present invention is the result of an extensive experimental testing program carried out by the inventors to screen pure metals and metal alloys. “Metals” is referred to in the broad sense as including transition metals, alkali metals, alkaline metal, lanthanide metals, post transition metals and / or their alloys. A wide variety of pure metals and metals alloys were tested in various gas compositions containing hydrogen at different temperatures and pressures. The focus was on applications at high temperature (above about 450°C); however, this invention may also be used at lower temperatures in some circumstances.

[0084] The interaction of metals with hydrogen molecules in the process of the invention involves various physical and chemical processes, including adsorption of H2molecules onto the metal surface, dissociation of H2molecules into H atoms, diffusion of atomic hydrogen through the metal material, recombination of atomic hydrogen to form molecular H2, and desorbing of H2molecules from the metal surface.

[0085] The materials evaluation process carried out by the present inventors considered metal composites and bimetallic coating to maximize the catalytic effect for hydrogen dissociation, hydrogen diffusion as well as hydrogen sorption capacity. The inventors have identified a group of metallic materials that can selectively sorb hydrogen at high temperatures. In embodiments of the invention, these materials are integrated into equipment designs and process configurations to process a stream of hot mixed process gases to produce a stream of gas substantially free of hydrogen and a steam of pure hydrogen product.Transition metals (including Pd, Cu, V, Nb, Ta, Ti, Ni and Zr) with and without precious metal coatings (including Pd and Ru) were tested in a controlled environment under hydrogen exposure. Alloying elements can include one or more of V, Nb, Ta, Ti, Zr, La, Al, Fe, Mg, Pd, Ag, and Ru. Molten alloys include: Pb-Li, Al-Cu, Cu-Li, Al-Li, Al-Mg, Al-Si-Cu, Ti-AI, Ti-La, and La-Ni. Further testing of pure metals and metallic alloys without precious metal coating provided good results that were in many ways surprising.

[0086] A surprising result of the testing was that the sorption / desorbing characteristics of some metals improved as temperature was increased as follows:

[0087] • High-temperature allowed for fast kinetics for hydrogen dissociation which was enough to provide sufficient kinetics for materials used as a sorbent without a special catalytic layer.

[0088] • High-temperature operation allowed for fast sorption rates and equilibrium was achieved over short time periods.

[0089] • Repeated sorption and desorbing operation did not cause substantial deterioration of the materials.

[0090] • Exposure of the materials to oxidizing atmospheres, although generating an oxidated layer, was easily regenerated once reducing conditions were established at high temperature.

[0091] • Problems such as hydrogen embrittlement are substantially reduced at higher temperatures, especially when used a sorbent which does not require the mechanical integrity of a membrane that must withstand high transmembrane pressures.

[0092] • Pure metals and metal alloys of low cost (on a mass basis and on a molar basis) provided high sorption rates and high sorption capacity and can be introduced in a variety of low cost form factors without the substantial mechanical support challenges of membranes.

[0093] The regenerable metallic sorption material 101 of the invention was compared against conventional membrane systems in Table 1 below:Table 1 - Comparison of conventional membranes against the regenerable metallic sorption materials of the present invention

[0094]

[0095]

[0096] Figure 3 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable metallic sorption material 101 is tantalum foil. This figure presents hydrogen sorption tests at 550°C and 1 bar(a). The sorption testing was followedby desorbing of hydrogen, and testing was repeated for multiple cycles. It was found that the rate of sorption as well as the total hydrogen capacity increased overtime. Substantial sorption was achieved in under 20 seconds, while saturation of capacity was observed at close to 100 seconds. The arrow marked “Time direction” in the figure indicates the success of the cycles over time, the first cycle being marked on the graph with circles.

[0097] Figure 4 provides experimental data for the sorption of hydrogen in an embodiment of the invention where the regenerable metallic sorption material 101 is a sample of tantalum foil operating at 550°C and 1 bar(a). The initial cycle (marked with circles) was performed when the material surface was oxidized, which showed slower kinetics. The sorption rate was recovered after the second test, achieving substantial sorption was achieved in under 20 seconds, while saturation of capacity was observed at close to 100 seconds. The exposure of oxygen to Ta slowed down hydrogen sorption / desorbing. Ta was able to recover its performance by hydrogen reduction which is a requirement for the intended application. Figure 5 provides experimental data for sorption of hydrogen in an embodiment of the invention where the regenerable metallic absorption material 101 is a sample of tantalum exposed to various temperatures from 400°C to 600°C and a pressure of 2 bar(a). The lower temperature tests showed slower sorption rates and the higher temperature tests showed much faster sorption. The hydrogen storage capacity increases as temperature is decreased. Industrial applications of the invention may balance the tradeoffs of speed and capacity. The kinetics of Ta for hydrogen sorption / desorbing increased with time and temperature. At high temperatures (>550°C), the initial kinetics of Ta without Pd coating for hydrogen sorption / desorbing was similar with that with Pd coating; however, the sample with the Pd coating showed rapid degradation. The kinetics of Ta without Pd coating for hydrogen sorption / desorbing was stable for the testing period, and no degradation was observed. Absorption curves for tantalum with Pd coating are shown in Figure 9.

[0098] The capacity of the regenerable metallic sorption material 101 is proportional to the number of moles of material available for the hydrogen to diffuse into. However, the price of metals is published on a mass basis. The most economic sorption materials would meet the following requirements:• Lower cost for a given hydrogen capacity. For instance, metals such as tantalum are at least two orders of magnitude less expensive than palladium. Metals such as titanium are an order of magnitude less expensive than tantalum due to its lower cost on a mass basis and also lower atomic mass.

[0099] • High catalytic activity at process temperature and high diffusivity into the bulk metal to achieve high effective H2absorption into the material.

[0100] • High sorption capacity at steady state on a molar basis.

[0101] • Ability to sustain multiple cycles without deterioration of performance.

[0102] • High surface area. This can be modified based on the system design allowing for high surface area when using absorbent mesh, particles, or molten materials in well- designed gas-liquid contactors.

[0103] • Resistance to chemical and / or physical deactivation or ability to fully regenerate in a process system. This is relevant in terms of the ability to regenerate an oxidation layer once the material is exposed to a reducing atmosphere.

[0104] Figure 6 provides experimental data for the absorption of hydrogen in an embodiment of the invention where the regenerable metallic sorption material 101 is titanium Grade 2 foil. This figure presents hydrogen absorption tests at 700°C. It was found that the hydrogen capacity could reach 0.5 mol H per mol Ti. Substantial absorption was achieved in under 20 seconds, while saturation of capacity was observed at close to 120 seconds.

[0105] Figure 7 provides experimental data for the absorption of hydrogen in an embodiment of the invention where the regenerable metallic sorption material 101 is titanium Grade 2 mesh. This figure presents hydrogen absorption tests at 700°C and 1 bar(a). It was found that the hydrogen capacity could reach 0.9 mol H per mol Ti. Substantial absorption was achieved in under 5 seconds, while saturation of capacity was observed at close to 20 seconds. The Ti mesh provides high surface area which allows for rapid absorption.

[0106] Multiple metals were tested including various transition metals. Testing was carried out at 700°C to 1000°C observing similar trends. Excellent performance was observed for various titanium alloys. Testing included ultra-pure Ti and commercial alloys of Ti including G1 toG9. Each had different levels of purity and composition profiles. Figure 8 presents the absorption results for Ti of various grades at 700°C and 1 bar(a). Repeatable trends are observed at higher temperatures for various compositions showing accelerated kinetics, while degradation of the material was not observed.

[0107] Testing showed that transition metals had very slow hydrogen sorption / desorbing at lower temperatures (<400°C). Low temperature applications would require very long residence times to be of industrial significance. Moreover, coating with Pd and other precious metals can accelerate kinetics, but this benefit is largely negated at higher temperatures (>500°C) due to the interdiffusion and degradation. Experimental results confirmed that no coating was required for transition metals for hydrogen sorption / desorbing at higher temperatures. Ti alloys showed higher hydrogen sorption capacity than Ta. At 700+°C Ti alloys showed rapid kinetics for hydrogen sorption / desorbing, in particular for the higher purity grades (e.g. G1 and G2).

[0108] Table 2 below provides experimental results of measurements of the hydrogen capacity of various metals. The hydrogen sorption capacity varied greatly. For example, Ni did not show measurable sorption capacity under the conditions tested. Ti and Zr showed excellent hydrogen sorption capacity.

[0109] Table 2

[0110]

[0111] In general, hydrogen separation process is operated in PSAD (Pressure Swing Adsorption / Desorption) orTSAD (Temperature Swing Adsorption / Desorption). In broadterms, PSAD requires the adsorption material to be sensitive to pressure change, and TSAD to temperature change. Single metals may be difficult to meet this requirement. The best materials are alloy materials. Based on the test results, the preferred operating temperature for various base metals are as follows:

[0112] >

[0113] >

[0114] >

[0115] <

[0116]

[0117] Figure 10 provides images for an embodiment of the invention where the regenerable sorption metallic material 101 is titanium G2 mesh. The lower images are close-ups of the mesh shown in the upper images. The images on the left show the material before absorption / desorbing cycling, the images in the center show the material after 85 cycles, and the images in the right show the material after 30 cycles. The images were taken by a scanning electron microscope (SEM) at a scale of 500 to 50 pm. Repeated cycling has an effect on the structure of the metal, but the material maintains its absorption / desorbing properties. In the intended applications of the invention, there is no need to maintain a specific shape of the material 101, and maximum surface area is often beneficial.

[0118] Figures 11 to 15 provide SEM images for embodiments of the invention where the regenerable hydrogen sorbent metallic material is Ti, Pd, Ta, V, Zr before (left) and after (right) absorption desorption cycles. It was proven that the absorption and desorption cycles are repeatable and that the materials were able to maintain sufficient integrity.

[0119] Stability testing was also performed to verify that the material can be regenerated after being exposed to an unfavorable atmosphere. For instance, the materials were exposed to oxygen to oxidize the surface, exposed to steam, and also exposed to industrially relevant mixtures of hydrocarbon gas. The initial cycle right after exposure, for all materials, shows reduced hydrogen sorption rate and lower hydrogen sorption capacity. The material wasthen exposed to a reducing atmosphere rich in hydrogen, and the performance of the material substantially recovered after the second cycle, and fully recovered after the third cycle.

[0120] Surface area of the regenerative hydrogen sorbent metallic material 101 was determined to be important. High surface area allows for faster sorption and desorbing, which favours the implementation of regenerative hydrogen sorbent metallic materials in forms such as solid metal mesh and filaments, solid metal fragments, solid metal particles, liquid metal with gas dispersed into the liquid, and liquid metal with liquid dispersed into the gas.

[0121] Gas-solid contacting was determined to be important to ensure adequate mass transfer to and from the regenerable metallic absorption material. For this reason, the following contacting devices are preferred:

[0122] • Gas-solid contact in packed beds.

[0123] • Gas-solid contact in moving beds.

[0124] • Gas-solid contact in fluidized beds (bubbling, turbulent, fast fluidization and conveying).

[0125] • Gas-liquid contact in molten metal systems including: bubble columns, molten metal sparged reactors, lance injected reactors, top blowing systems, bottom blowing systems, tuyere-based systems, spray systems and contactors with solid internals designed to promote mixing and interfacial area.

[0126] Examples

[0127] Some specific examples of embodiments for the implementation of processes and devices for regenerative separation of hydrogen gas are depicted schematically in Figures 16 to 21. It will be understood that the schematics and descriptions focus on the core system concept. Additional details and ancillary equipment well known to persons skilled in the art are necessary for an industrial application, and the system can have more vessels to allow for improved operability. Ancillary equipment such as control systems, heat exchangers, isolation and switching valves, ancillary lines, gas conditioning systems, buffer tanks,blowers and pressure changing equipment, lock hoppers, vents, and other items are not depicted.

[0128] Example 1

[0129] A regenerative hydrogen sorber / desorber system 10 is schematically illustrated in Figure 16. In this example embodiment of the invention, the regenerable hydrogen sorbent metallic material 101 is contained in at least two vessels 102A / 103A and 102B / 103B and the material is kept inside the respective vessel. The sorption / desorbing vessel 102A / 103A is 102A when in sorption duty and 103A when in desorbing duty. The sorption / desorbing vessel 102B / 103B is 102B when in sorption duty and 103B when in desorbing duty. A source of hydrogen-containing gas 1 is fed into the process vessels where the regenerable hydrogen sorbent metallic material 101 selectively sorbs hydrogen gas while allowing the other species to pass through and leave the system as a gas stream 2 substantially free of hydrogen gas. The regenerable hydrogen sorbent metallic material 101 holds the hydrogen until a regeneration cycle is activated, by changing the operating conditions (the temperature is increased or the partial pressure of hydrogen is decreased). During regeneration, a stream of substantially pure hydrogen gas 3 is produced as the product. The sorption unit operations 102A and 102B are performed as follows:

[0130] • Operated a temperature above 300°C, preferably in the range of 550°C to 2000°C, and most preferably in the range of 700°C to 1200°C.

[0131] • Operated at a pressure above 0.1 bar (a), preferably above 1 bar(a), preferably above 10 bar(a), and most preferably above 20 bar(a).

[0132] • The hydrogen-containing gas 1 feed contains over 0.1% H2mol / mol, preferably over 1% H2mol / mol, and most preferably over 10% H2mol / mol.

[0133] • The gas stream 2 substantially free of hydrogen gas contains lower H2concentration than the feed gas, preferably less than 10% H2mol / mol, and most preferably less than 0.1% H2mol / mol.

[0134] • The sorption cycle residence time is over 0.1 seconds, preferably between 5 and 3600 seconds, and most preferably between 300 and 600 seconds.The regenerable hydrogen sorbent metallic material 101 is kept inside each of the process vessels:

[0135] • The material 101 comprises a transition metal or its alloys, preferably containing titanium or its alloys.

[0136] • It is in solid metal mesh form, solid particle form or in molten form. The surface area of the metal if in solid form may be over 1 ,000 m2 / m3of material, alternatively over 40,000 m2 / m3.

[0137] • If the material is in solid metal form, it is contacted with gas using a solid packed bed, a bubbling regime fluidized bed, a turbulent regime fluidized bed, a spouted bed, or a similar gas-solid contactor.

[0138] • If the material is in molten metal form, it is contacted with gas using a bubble column, sparged reactors, lance injected reactor, top / bottom blowing system, and other gas-liquid contactors.

[0139] The desorbing unit operations 103A and 103B are performed as follows:

[0140] • Operated a temperature equal or higher than the sorption step, preferably over 50°C hotter than the sorption step and most preferably over 100°C hotter than the sorption step.

[0141] • Operated a pressure equal or lower than the sorption step, preferably at least 0.1 bar (a) lower, than the sorption step, more preferably at least 1 bar(a) lower than the sorption step and most preferably at least 10 bar(a) lower than the sorption step.

[0142] • The stream of substantially pure hydrogen gas 3 contains higher H2concentration than the feed gas, preferably over 95% H2mol / mol, and most preferably over 99.99% H2mol / mol.

[0143] • The desorbing cycle residence time is over 0.1 second, preferably between 5 and 3600 seconds, and most preferably between 300 and 600 seconds.

[0144] Example 2Another embodiment of the regenerative hydrogen sorber / desorber system 10 is schematically illustrated in Figure 17. In this example, the regenerable hydrogen sorbent metallic material 101 is used as a hydrogen carrier. A source of hydrogen-containing gas 1 is fed into the sorption vessel 102 where the regenerable hydrogen sorbent metallic material 101A selectively sorbs hydrogen gas while allowing the other species to leave the system as a gas stream 2 substantially free of hydrogen gas. The regenerable hydrogen sorbent metallic material once loaded with H2101 B is used as a carrier and fed into the desorbing vessel 103. In the desorbing vessel 103 the sorption material 101C releases H2under the desorbing process conditions. During regeneration, a stream of substantially pure hydrogen gas 3 is produced as product.

[0145] The sorption unit operation 102 is performed as follows:

[0146] • Operated a temperature above 300°C, preferably in the range of 550°C to 2000°C, and most preferably in the range of 700°C to 1200°C.

[0147] • Operated at a pressure above 0.1 bar (a), preferably above 1 bar(a), preferably above 10 bar(a), and most preferably above 20 bar(a).

[0148] • The hydrogen-containing gas 1 feed contains over 0.1% H2mol / mol, preferably over 1% H2mol / mol, and most preferably over 10% H2mol / mol.

[0149] • The gas stream 2 substantially free of hydrogen gas contains lower H2concentration than the feed gas, preferably less than 10% H2mol / mol, and most preferably less than 0.1% H2mol / mol.

[0150] • The gas residence time is over 0.1 seconds, preferably between 5 and 3600 seconds, and most preferably between 300 and 600 seconds.

[0151] The regenerable hydrogen sorbent metallic material 101A / B / C / D is transported between vessels as a hydrogen carrier:

[0152] • The material is loaded with hydrogen in the sorber, and then it is conveyed to the desorber where it releases H2. The material once regenerated is transported back to the desorber to complete the cycle.• The material comprises a transition metal or its alloys, preferably containing titanium or its alloys.

[0153] • It is in solid metal particle form or in molten form. The surface area of the metal if in solid form may be over 1 ,000 m2 / m3of material, alternatively over 40,000 m2 / m3.

[0154] • If the material is in solid metal form, it is contacted with gas using, a bubbling regime fluidized bed, a turbulent regime fluidized bed, a circulating fluidized-bed, or a similar gas-solid contactor. The particulate regenerable metallic absorption material is circulated between the two vessels.

[0155] • If the material is in molten metal form, it is contacted with gas using a bubble column, sparged reactors, lance injected reactor, top / bottom blowing system, and other gas-liquid contactors. The molten metal of regenerable metallic absorption material is circulated between the two vessels.

[0156] The desorbing unit operation 103 is performed as follows:

[0157] • Operated a temperature equal or higher than the sorption step, preferably over 50°C hotter than the sorption step and most preferably over 100°C hotter than the sorption step.

[0158] • Operated a pressure equal or lower than the sorption step, preferably at least 1 bar(a) lower than the sorption step and most preferably at least 10 bar(a) lower than the absorption step.

[0159] • The stream of substantially pure hydrogen gas 3 contains higher H2concentration than the feed gas, preferably over 95% H2mol / mol, and most preferably over 99.99% H2mol / mol.

[0160] • The desorbing cycle residence time is over 0.1 second, preferably between 5 and 3600 seconds, and most preferably between 300 and 600 seconds.

[0161] Example 3

[0162] Figure 18 illustrates an embodiment of the invention that provides a system 20 that combines a hydrogen production system with a regenerative hydrogen sorption / desorbingsystem. This example integrates the hydrogen production step with the hydrogen separation step. The feedstock 4 for hydrogen production is fed into a hydrogen production reactor 104 having a hydrogen production reactor catalyst 105. The reactor product is a stream 1 of hydrogen-containing gas which is fed into the regenerative hydrogen sorber / desorber system 10 which is operated in similar fashion to that described above in Example 1 and Example 2. A stream of substantially pure hydrogen gas 3 is produced as product.

[0163] The feedstock 4 for hydrogen production and hydrogen production reactor 104 can be as follows:

[0164] • Steam methane reforming. In this case the feedstock 4 is natural gas, methane or higher molecular weight hydrocarbons and steam. The reactor 104 in such case is a steam reforming reactor which uses a reforming catalyst such as a nickel-based catalyst. The reforming reactor can be a fixed bed or fluidized bed catalytic reactor or other configurations known to a person skilled in the art. The reforming reactor can be of conventional SMR configuration or autothermal configuration and operate under industrially relevant process conditions: in the range of 700°C to 950°C, and in the range of 10 to 40 bar(a).

[0165] • Hydrocarbon pyrolysis reactor. In this case the feedstock 4 is natural gas, methane or higher molecular weight hydrocarbons. The pyrolysis reactor 104 cracks the hydrocarbons and produces a stream of hydrogen-containing gas as well as a solid carbon product (not shown). The pyrolysis reactor typically operates at temperatures above 1000°C.

[0166] • Gasification reactor: In this case the feedstock 4 can be wood chips, sawdust, forestry products, waste materials, biosolids, fossil fuels, etc. The gasification reactor 104 produces a syngas stream that contains hydrogen. The reactor temperature varies depending on the technology but is typically in the range of 700°C to 1200°C.

[0167] • Dehydrogenation reactors: In this case, the feedstock is a chemical (e.g., a hydrocarbon such as propane, ethane, ethylbenzene, 2-butanol, etc.) undergoing a dehydrogenation reaction at elevated temperatures. The dehydrogenation reactor often produces unsaturated hydrocarbons (e.g., propylene, ethylene, styrene, methyl ethyl ketone (MEK), etc.), together with hydrogen as a coproduct. The reactortemperature and pressure vary depending on the specific application / technology and process employed but are typically in the range of 200°C to 800°C and 0.1 to 30 bar.

[0168] • Ammonia crackers: In this case, the feedstock is an ammonia-rich gas, and the cracking unit produces a gas mixture containing primarily hydrogen and nitrogen. The reactor temperature and pressure vary depending on the technology and desired product specifications but are typically in the range of 400°C to 900°C and 1 to 30 bar.

[0169] • Other high-temperature reactors: There are other reaction systems including high- temperature water splitting that can produce hydrogen at high temperature, and the present invention can incorporate such reactors.

[0170] A stream 2 depleted of hydrogen gas is produced. This stream 2 can:

[0171] • Be recycled back into the main reactor 104, via stream 6.

[0172] • Be used directly in a downstream process based on its energy and chemical value, via stream 5.

[0173] • Be fed into a shift converter for the case of steam methane reforming. A shift converter can be used to increase the yield of hydrogen by means of the water-gas shift reaction. The shift converter can be operated in the range of 200°C to 400°C to allow for additional hydrogen production. Since the process gas already had hydrogen removed, this will push the chemical equilibrium forward in a single reactor to considerably enhance the hydrogen yield as compared to conventional technology. The present invention can eliminate at least one cooling stage and a shift converter stage as compared to SMR technology because it would have a more reactive gas with a better equilibrium profile, in accordance with Le Chatelier’s principle.

[0174] Example 4

[0175] Figure 19 illustrates an embodiment of the invention that provides a system 20 that combines a steam methane reforming (SMR) system with a regenerative hydrogen sorption / desorbing system. Natural gas 4 is fed into a SMR reactor 104, and the reactionproducts 1 (containing H2, CO, H2O, CO2, CH4) are fed into the regenerative hydrogen sorber / desorber system 10 which is operated in a manner similar to that described above in Examples 1, 2, and 3.

[0176] The hydrogen-depleted gas 5 is cooled in a heat exchanger 106 and fed into a shift converter reactor 107. A single low-temperature shift converter is used since the gas has already had hydrogen removed, which provides better equilibrium conditions, in accordance with Le Chatelier’s principle. The shift converter reactor 107 is operated at a temperature in the range of 150°C to 300°C, more preferably in the range of 200°C to 250°C. The product hydrogen-rich gas 7 can be either (a) used directly for its hydrogen value, (b) recirculated back to the sorber reactor 102, or (c) taken to a conventional low temperature hydrogen separation system.

[0177] Example 5

[0178] Figure 20 illustrates an embodiment of the invention that provides a system 20 that performs in situ regenerative hydrogen sorption / desorbing in a hydrogen production system. The core hydrogen production system can be a reforming reactor, pyrolysis reactor or gasification reactor. In this example the regenerable hydrogen sorbent metallic material 101 is mixed with the hydrogen production reactor catalyst 105. A single vessel 104 / 102 acts as a sorption vessel 102 and a hydrogen production reactor 104. The mixed material 105 / 101 is circulated between the hydrogen production / sorption vessel 104 / 102 and a separate desorbing vessel 103.

[0179] The hydrogen production reactions are greatly enhanced by the in situ hydrogen sorption process taking place inside vessel 104 / 102. The hydrogen removal process shifts the equilibrium forward allowing for higher conversions and higher hydrogen yields in a single unit operation. Desorbing vessel 103 produces a stream of substantially pure hydrogen gas 3.

[0180] The hydrogen production and sorption unit operation 104 / 102 are performed as follows:

[0181] • Operated a temperature above 500°C, preferably in the range of 600°C to 2000°C, and most preferably in the range of 500°C to 900°C.• Operated at a pressure above 0.1 bar (a), preferably above 1 bar(a), preferably above 10 bar(a), and most preferably above 20 bar(a).

[0182] Catalyst and regenerable absorption material 105 / 101 are transported between the vessels 104 / 102 and 103 on a continuous or semi-continuous manner. If the material 105 / 101 is in solid metal form, it is contacted with gas using, a bubbling regime fluidized bed, a turbulent regime fluidized bed, a circulating fluidized-bed, ora similar gas-solid contactor. If the material 105 / 101 is in molten metal form, it is contacted with gas using a bubble column, sparged reactors, lance injected reactor, top / bottom blowing system, and other gas-liquid contactors.

[0183] The desorbing unit operation 103 is performed as follows:

[0184] • Operated at a temperature equal or higher than the sorption step, preferably over 50°C hotter than the sorption step and most preferably over 100°C hotter than the sorption step.

[0185] • Operated at a pressure equal or lower than the sorption step, preferably at least 1 bar(a) lower than the sorption step and most preferably at least 10 bar(a) lower than the sorption step.

[0186] • The stream of substantially pure hydrogen gas 3 contains higher H2concentration than the feed gas 4, preferably over 95% H2mol / mol, and most preferably over 99.99% H2mol / mol.

[0187] Example 6

[0188] Figure 21 illustrates an embodiment of the invention that provides a system 20 that performs in situ regenerative hydrogen sorption / desorbing in a hydrogen production system. The core hydrogen production system is a fixed-bed steam methane reforming reactor. In this example, the regenerable hydrogen sorbent metallic material 101 is mixed with the hydrogen production reactor catalyst 105. A single vessel 104 / 102 / 103 acts as hydrogen production reactor 104, sorption vessel 102, and desorbing vessel 103. The mixed material 105 / 101 is kept inside the vessel 104 / 102 / 103 in fixed-bed configuration. To maintain continuous operation, more than one vessel of identical configuration is required (one vessel for batch operation, two or more vessels for continuous operation, and a series ofvessels for optimal operability). Figure 21 illustrates an embodiment having three such vessels.

[0189] The hydrogen production reactions are greatly enhanced by the in situ hydrogen sorption process taking place inside vessel 104 / 102 / 103.

[0190] The hydrogen production, sorption, and desorbing unit operations 104 / 102 / 103 are performed in the following sequence:

[0191] 1. Natural gas and steam are fed to vessel 104 / 102 / 103 where it is exposed to steam reforming catalyst 105 as well as regenerable hydrogen absorption material 101. The system is operated a temperature above 500°C, preferably in the range of 500°C to 900°C, and most preferably in the range of 600°C to 900°C. The system pressure is above 0.1 bar (a), preferably above 1 bar(a), preferably above 10 bar(a), and most preferably above 20 bar(a). In this stage, methane reacts with steam to produce hydrogen. The hydrogen is immediately sorbed into the sorption material 101. The hydrogen removal process shifts the equilibrium forward allowing for higher conversions and higher hydrogen yields in a single unit operation.

[0192] 2. Once this step is complete, or the hydrogen sorption capacity of the system is saturated, then the feed 4 is switched to a second vessel 104 / 102 / 103 that would begin its own cycle.

[0193] 3. The vessel that contains regenerable hydrogen sorption metallic material saturated in hydrogen will begin a regeneration cycle to desorb the hydrogen captured. The operating conditions are changed to a temperature equal or higher than the sorption step, preferably over 50°C hotter than the sorption step and most preferably over 100°C hotter than the sorption step. Alternatively, the pressure of the system is lowered as compared to the sorption step, preferably at least 1 bar(a) lower than the sorption step and most preferably at least 10 bar(a) lower than the sorption step. This produces a stream of substantially pure hydrogen gas 3.4. The cycle is repeated in a controlled manner to provide continuous hydrogen production. A person skilled in the art will recognize the need for switching valves, control systems, intermediate purging and equalization tanks.

[0194] 5. The hot hydrogen product 3 is then fed to a process that requires hot hydrogen, such as hydrodesulphurization, to improve energy integration, eliminate heat exchange equipment and save energy.

[0195] Example 7

[0196] Figures 22 to 24 illustrate alternative embodiments of the invention, which performs in situ regenerative hydrogen sorption / desorption in a dehydrogenation process 30. Non-limiting examples of dehydrogenation processes include alkane (propane, ethane, butane, etc.) dehydrogenation, ethylbenzene dehydrogenation, 2-butanol dehydrogenation, naphtha steam crackers, and ammonia crackers. For simplicity, this alternative embodiment is described in the context of propane dehydrogenation (PDH) plants, where a gaseous stream containing propane 8 undergoes a dehydrogenation reaction to produce a propylene-rich stream 11.

[0197] Propane dehydrogenation relies on an endothermic reaction typically conducted in the presence of a catalyst at 500-750°C and 0.3-5 bar (a). The process is prone to coke formation and catalyst deactivation, which necessitates continuous or cyclic catalyst reactivation through burning coke, generating a process flue gas 10. The current market is primarily governed by two major technologies: CATOFIN™ by Lummus, which employs fixed-bed reactors with chromium-based catalysts, and OLFLEX™ by UOP, which employs moving-bed reactors with platinum-based catalysts. Other technologies also exist, including STAR™ by Uhde and DOW / OpTe™. For simplicity, this example is described for Lummus CATOFIN™ PDH plants, but similar applicability is found on other dehydrogenation processes.

[0198] CATOFIN™ PDH technology features cyclic operation with two or more (typically 4-8) vessels installed in parallel or series. At any given time, at least one vessel 108 is fed with propane-rich gas 8 and undergoes the dehydrogenation reaction to produce propylene.Simultaneously, at least one vessel 109 is in catalyst reactivation mode, in which air is typically used to bum coke and re-oxidize the chromium-based catalyst. Catalyst reactivation also generates flue gas 10, which is typically treated before exhaust. The process may further include other periodic steps, such as pressurizing, depressurizing, and gas purging. This alternative embodiment is described for a CATOFIN™ PDH plant with two parallel reactor vessels.

[0199] Typical per-pass feedstock conversion in PDH reactors lies between 30-60% due to thermodynamic (equilibrium) limitations, with part of the gas undergoing side reactions such as cracking and hydrogenolysis, as shown in the table below. This results in a gas mixture of hydrocarbons (e.g., propane, propylene, methane, ethylene, hydrogen, etc.) at the reactor outlet, which requires further downstream separation and purification.

[0200] Key Reactions in PDH Process

[0201] >

[0202]

[0203] Downstream separation processes 40 in PDH plants may include acid gas removal systems, dryers, flash drums, heat exchangers, cold boxes, cryogenic deethanizers, and cryogenic propane / propylene splitters, etc. These processes produce a propylene-rich product stream 11, as well as one or more byproduct streams 12 (e.g., hydrogen-rich gas, methane-rich gas, ethane-rich gas, etc.), depending on the process configuration. The system typically produces a propane-rich recycle stream 6, wherein propane recovered from downstream separation units is returned to the process inlet to enhance overall feedstock conversion in the plant. Certain technologies may also include partial recycle of hydrogen-rich gas recovered from downstream separation processes to assist in managing coke formation and / or reducing product or feedstock / product losses.In this example, regenerable hydrogen sorbent metallic material 101 is mixed with the dehydrogenation catalyst 111 inside the PDH reactor vessels 108 / 109 / 110. At any given time, a vessel 108 undergoing propane dehydrogenation generates significant hydrogen, which is at least partly removed from the reactor gas by the sorbent metallic material 101. This shifts the thermodynamic equilibrium of the propane dehydrogenation reaction toward higher conversion while simultaneously shifting the equilibrium of the hydrogenolysis reaction toward lower conversion. Thus, in situ hydrogen separation by the regenerable hydrogen sorbent metallic material 101 allows for enhanced production yield and selectivity in PDH plants.

[0204] Each reactor vessel undergoes periodic changes in operating conditions, alternating between the PDH reaction 108 and catalyst reactivation 109. This periodic operation aligns well with the cyclic regeneration of the regenerable hydrogen sorbent metallic material 101 required for continuous operation. Sorbent regeneration 110 may be conducted simultaneously with catalyst reactivation 109 as a single cyclic step, as shown in Figure 22, or as a separate step within the cyclic operation, which may require at least one additional reactor vessel, as shown in Figure 23. The sequence of the cyclic operations depends on the process conditions, with sorbent regeneration occurring either before or after catalyst reactivation. Some embodiments may also include an optional sorbent reactivation step, typically conducted via sorbent hydrogenation, which may be implemented before or after the sorbent regeneration step

[0205] In addition to shifting the reaction equilibrium forward via in situ hydrogen removal, this embodiment, when sorbent regeneration is implemented as a separate cyclic step (as in Figure 23), enables recovery of a high-purity hydrogen stream 3 from PDH plants without the need for additional downstream hydrogen separation units. Furthermore, at least a portion of the energy required for the endothermic PDH reaction can be supplied by the exothermic hydrogen absorption into the metallic absorption material 101, thereby enhancing heat management and overall plant energy efficiency.

[0206] This embodiment can also allow for smaller and / or fewer process equipment, reduced energy consumption (e.g., lower compression and / or cryogenic separation costs), andenhanced material recovery due to reduced hydrogen dilution in downstream separation processes.

[0207] Figure 24 shows an alternative embodiment of the invention, in which the system is applied to produce propylene using a Propane Dehydrogenation (PDH) plant where the main reactor is enhanced by the present hydrogen regenerative absorption system. A propane-rich gas feedstock 8 is sent to a depropanizer unit 201 to separate heavy hydrocarbons 13 upstream of the PDH catalytic reactor a PDH reactor vessel 108, catalyst reactivation reactor vessel 109 and a sorbent regeneration reactor vessel 110. It is understood that unit operations 108 / 109 / 110 could be integrated into one or multiple vessels. The reactor converts its propane content to propylene, and hydrogen is selectively removed as it is produced within the reactor 108 / 109 / 110. The PDH reactor off-gas 9 is sent to a gas compressor 202, followed by a gas dryer and cryogenic separator / cold-box 203. This generates a mixture of propane / propylene-rich condensate, as well as a vapor / gas product 14, which is sent to a gas recycle system 204, returning a part of the process gas to the process upstream 15, and sending the rest to furnace and heat recovery unit 205. Part of the non-recycled gas can be withdrawn and serve as secondary byproduct 12a. The condensate product of the gas dryer and cryogenic separator / cold-box unit is fed to a series of multi-phase separation systems, including but not limited to a deethanizer 206 and a propane / propylene splitter 207. The deethanizer 206 separates a notable part of the remaining side products and impurities such as ethane, methane, and ethylene, producing a condensate highly enriched of propane and propylene. The vapor overhead of deethanizer 16 is sent to furnace and heat recovery unit 205, while part of this stream can be withdrawn and serve as secondary byproduct 12b. The condensate product of the deethanizer unit is sent to propane / propylene splitter 207, producing propylene 11 and a propane-rich condensate stream 6. The propane-rich condensate stream 6 is recycled to the process upstream to maximize overall plant conversion and propylene capacity. The process may optionally be configured to direct the recovered hydrogen 3 and the catalyst reactivation offgas 10 to the furnace and heat recovery unit 205, wherein an oxidizing gas (e.g., air) 17 is supplied to bum combustible gases and generate a process flue gas 18. In the present invention, the performance of the PDH reactor is improved by increasing productivity of the plant to the desired product and reducing the energy consumption and equipment size of downstream separation units.Where a component (e.g. a substrate, assembly, device, etc.) is referred to above, unless otherwise indicated, reference to that component (including a reference to a “means”) should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments described herein.

[0208] Specific examples of systems, methods, and apparatus have been described herein for purposes of illustration. These are only examples. The technology disclosed herein can be applied to systems other than the example systems described above. Many alterations, modifications, additions, omissions, and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled addressee, including variations obtained by: replacing features, elements and / or acts with equivalent features, elements and / or acts; mixing and matching of features, elements and / or acts from different embodiments; combining features, elements and / or acts from embodiments as described herein with features, elements and / or acts of other technology; and / or omitting combining features, elements and / or acts from described embodiments.

[0209] It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, omissions, and sub-combinations as may reasonably be inferred. 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.

Claims

Claims1. A method of regenerative hydrogen separation in which hydrogen gas is selectively removed from a hydrogen-containing gas comprising the hydrogen gas and other gas species, the method comprising the steps of:(a) contacting a regenerable hydrogen sorbent metallic material with the hydrogencontaining gas, at a first temperature and a first partial pressure of hydrogen;(b) selectively sorbing hydrogen from the hydrogen-containing gas into the regenerable hydrogen sorbent metallic material;(c) producing a gas stream with a reduced level of hydrogen gas; and(d) exposing the regenerable hydrogen sorbent metallic material with sorbed hydrogen to a second temperature and / or a second partial pressure of hydrogen, wherein the second temperature is higher than the first temperature and / or the second partial pressure is lower than the first partial pressure, thereby desorbing hydrogen gas from the regenerable hydrogen sorbent metallic material to produce a stream of purified hydrogen gas.

2. The method according to claim 1, wherein step (a) is carried out in at least one process vessel containing the regenerable hydrogen sorbent metallic material, further comprising:- feeding the stream of hydrogen-containing gas to the process vessel(s);- in step (c) allowing the other gas species to pass from the process vessel(s) to produce the gas stream with a reduced level of hydrogen gas; and- flowing the stream of purified hydrogen gas produced in step (d) from the process vessel(s).

3. The method according to claim 1, wherein step (a) is carried out in at least one sorption vessel(s) containing the regenerable hydrogen sorbent metallic material, further comprising:- feeding a stream of the hydrogen-containing gas to the sorption vessel(s);- in step (c) allowing the other gas species to pass from the sorption vessel(s) to produce the gas stream with a reduced level of hydrogen gas;- feeding the regenerable hydrogen sorbent metallic material with sorbed hydrogen to at least one desorbing vessel having the second temperature and / or the second partial pressure of hydrogen; and- flowing the stream of purified hydrogen gas from the desorbing vessel(s).

4. The method according to claim 3, further comprising the step, after step (d), of feeding the regenerable hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel back to the sorption vessel(s).

5. The method according to any one of claims 1 to 4, further comprising the steps of:- feeding a feedstock for hydrogen production to at least one hydrogen production reactor; and- producing in the hydrogen production reactor(s) the hydrogen-containing gas used in step (a).

6. The method according to claim 5, wherein multiple alternating stages of hydrogen production and sorption are performed sequentially either in one vessel, or multiple vessels arranged in series or parallel.

7. The method according to claim 1 in combination with a method of production of hydrogen gas and / or dehydrogenation of hydrocarbons, further comprising:- feeding a feedstock for hydrogen production and / or hydrocarbon dehydrogenation into at least one hydrogen production and sorption vessel;- performing at least one hydrogen production and / or hydrocarbon dehydrogenation reaction in the presence of the regenerable hydrogen sorbent metallic material using the feedstock in the hydrogen production and sorption vessel(s);- producing the hydrogen-containing gas simultaneously with step (b);- in step (c) allowing the other gas species to pass from the hydrogen production and sorption vessel(s) to produce the gas stream with a reduced level of hydrogen gas;- feeding the regenerable hydrogen sorbent metallic material with sorbed hydrogen to at least one desorbing vessel having the second temperature and / or second partial pressure of hydrogen; and- flowing the stream of purified hydrogen gas from the desorbing vessel(s).

8. The method according to claim 7, further comprising feeding the regenerable hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel(s) back to the hydrogen production and sorption vessel(s).

9. The method according to claim 1 in combination with a method of production of hydrogen gas and / or dehydrogenation of hydrocarbons, further comprising:- feeding a feedstock for hydrogen production and / or hydrocarbon dehydrogenation into at least one process vessel;- performing at least one hydrogen production and / or hydrocarbon dehydrogenation reaction in the presence of the regenerable hydrogen sorbent metallic material using the feedstock in the process vessel (s);- producing the hydrogen-containing gas simultaneously with step (b);- in step (c) allowing the other gas species to pass from the process vessel(s) to produce the gas stream with a reduced level of hydrogen gas; and- flowing the stream of purified hydrogen gas from the process vessel(s).

10. The method according to any one of the preceding claims, further comprising repeating the steps of the method using two or more process vessels arranged in series and / or parallel, to produce a continuous stream of the gas with a reduced level of hydrogen and / or purified hydrogen gas.

11. The method according to any one of the preceding claims, wherein the sorbing and / or desorbing steps are carried out in gas-solid contact in packed beds, gas-solid contact in moving beds, or gas-solid contact in fluidized beds.

12. The method according to any one of claims 5 to 10, wherein the hydrogen production and / or hydrocarbon dehydrogenation steps are carried out in gas-solid contact in packed beds, gas-solid contact in moving beds, or gas-solid contact in fluidized beds.

13. The method according to claim 11 or 12, wherein the fluidized beds are one of bubbling, turbulent, fast fluidization and pneumatic conveying.

14. The method according to any one of claims 1 to 10, wherein the sorbing and / or desorption steps are carried out in gas-liquid contact in molten metal systems.

15. The method according to any one of claims 5 to 10, wherein the hydrogen production step is carried out in gas-liquid contact in molten metal systems.

16. The method according to claim 14 or 15, wherein the molten metal systems are selected from the group consisting of bubble columns, molten metal sparged reactors, lance injected reactors, top blowing systems, bottom blowing systems, tuyere-based systems, and spray systems and contactors with solid internals.

17. A method according to any one of claims 3-8, wherein circulation of the regenerable hydrogen sorbent metallic material is carried out in liquid form.

18. The method according to any one of the preceding claims, wherein the sorbing step is carried out at a temperature above 25°C, alternatively in the range of 550°C to 2000°C, alternatively in the range of 700°C to 1200°C.

19. The method according to any one of claims 5-18, wherein the hydrogen production and / or hydrocarbon dehydrogenation step is carried out at a temperature above 25°C, alternatively in the range of 550°C to 2000°C, alternatively in the range of 700°C to 1200°C.

20. The method according to any one of the preceding claims, wherein the sorbing step is carried out at a pressure above 0.1 bar (a), alternatively above 1 bar(a), alternatively above 10 bar(a), alternatively above 20 bar(a).

21. The method according to any one of claims 5 to 20, wherein the hydrogen production and / or hydrocarbon dehydrogenation step is carried out at a pressure above 0.01 bar(a), alternatively above 0.1 bar (a), alternatively above 10 bar(a), alternatively above 20 bar(a).

22. The method according to any one of the preceding claims, wherein the hydrogencontaining gas comprises over 0.1% H2mol / mol, alternatively over 1% H2mol / mol, alternatively over 10% H2mol / mol.

23. The method according to any one of the preceding claims, wherein the produced stream with a reduced level of hydrogen gas contains lower hydrogen gas concentration than the hydrogen-containing feed gas, alternatively less than 10% H2mol / mol, alternatively less than 0.1% H2mol / mol.

24. The method according to any one of the preceding claims, wherein the sorption step has a solid / liquid residence time over 0.1 seconds, alternatively in the range of 5 to 3600 seconds, alternatively in the range of 300 to 600 seconds.

25. The method according to any one of the preceding claims, wherein the desorbing step is carried out at a temperature equal or higher than the sorption step, alternatively over 50°C hotter than the sorption step, alternatively over 100°C hotter than the sorption step.

26. The method according to any one of the preceding claims, wherein the partial pressure of hydrogen in the desorbing step is at least 0.1 bar(a) lower than in the sorption step, alternatively at least 10 bar(a) lower than in the sorption step.

27. The method according to any one of the preceding claims, wherein produced stream of purified hydrogen gas contains a higher hydrogen gas concentration than the hydrogencontaining feed gas, alternatively over 95% H2mol / mol, alternatively over 99.99% H2mol / mol.

28. The method according to any one of the preceding claims, wherein the step of desorbing hydrogen uses a sweep gas to reduce the hydrogen partial pressure and produce a purified stream of hydrogen gas in a sweep gas, and either using said stream in a downstream process and / or separating the hydrogen gas from said stream.

29. The method according to any one of the preceding claims, wherein the step of desorbing the hydrogen uses a reactive sweep gas to reduce the partial pressure of hydrogen to react with and consume some or all of the purified hydrogen.

30. The method according to any one of the preceding claims, wherein the desorbing step has a solid / liquid residence time of over 0.1 second, alternatively in the range of 5 to 3600 seconds, alternatively in the range of 300 to 600 seconds.

31. The method according to any one of the preceding claims, further comprising the step of feeding the purified hydrogen gas product to a process that requires hot hydrogen to improve energy integration, eliminate heat exchange equipment, or save energy.

32. The method according to any one of claims 5 to 31 , wherein the hydrogen production step is one of steam hydrocarbon reforming, hydrocarbon / methane pyrolysis, and gasification.

33. The method according to any one of claims 5 to 32, wherein the hydrogen production and / or hydrocarbon dehydrogenation step uses as feedstock one or more of methane, natural gas, liquid hydrocarbons, biomass, wood chips, sawdust, forestry products, waste materials, biosolids, propane, ethane, ethylbenzene, 2-butanol, naphtha, ammonia and other hydrocarbons for dehydrogenation.

34. The method according to any one of claims 6 to 33, wherein the hydrocarbon dehydrogenation reaction produces hydrogen and unsaturated hydrocarbons.

35. The method according to claim 34, wherein the unsaturated hydrocarbons comprise one or more of propylene, ethylene, styrene, acetylene, methyl ethyl ketone and formaldehyde.

36. The method according to any one of claims 6 to 35, wherein the step of selective sorption of hydrogen supplies at least a portion of heat required for the endothermic reactions within the reactor.

37. The method according to claim 36, wherein the endothermic reactions within the reactor comprise dehydrogenation, pyrolysis, reforming, decomposition, and cracking.

38. The method according to any one of the preceding claims, further comprising a step of reactivating the regenerable hydrogen sorbent metallic material for enhanced cyclic performance.

39. The method according to claim 38, wherein the step of reactivating the regenerable hydrogen sorbent metallic material comprises sorbent hydrogenation, performed before or after sorbent regeneration to enhance the cyclic performance of the regenerable hydrogen sorbent metallic material.

40. The method according to any one of claims 5 to 39, wherein the step of selectively absorbing / adsorbing hydrogen is performed in situ within a hydrogen production and / or hydrocarbon dehydrogenation reactor to remove hydrogen, shift the thermodynamic equilibrium of the desired reactions toward higher conversion, and / or shift the thermodynamic equilibrium of undesired side reactions toward lower conversion, thereby enhancing process selectivity and / or overall production yield for a desired product.

41. The method according to any one of the preceding claims, wherein the regenerable hydrogen sorbent metallic material comprises an alkali metal, alkaline metal, lanthanide metal, and / or transition metal or alloys.

42. A method according to claim 41 , wherein the transition metal is a metal selected from the group consisting of Ti, Ta, V, Nb, Ru, Pd, La, Ce and Zr.

43. The method according to claim 41 , wherein the alkal i / alkali ne / lanthanide / transition metal is alloyed with one or more alloying elements selected from the group consisting of V, Nb, Ta, Ti, Zr, La, Ce, Al, Fe, Mg, Pd, Ag, Ni and Ru.

44. The method according to claim 41 , wherein the alkal i / alkali ne / lanthanide / transition metal is alloyed with one or more elements to form an alloy selected from the group consisting of Pb-Li, Al-Cu, Cu-Li, Al-Li, Al-Mg, Al-Si-Cu, Ti-AI, Ti-La, Ce-Ni, and La-Ni.

45. The method according to any one of the preceding claims, wherein the regenerable hydrogen sorbent metallic material is a Ti alloy selected from the group consisting of commercial grade G1 to G9 Ti alloys, preferably from the group consisting of commercial grade G1 and G2 grade Ti alloys.

46. The method according to any one of the preceding claims, wherein the regenerable hydrogen sorbent metallic material is in the form of solid metal mesh and filaments, solid metal fragments, solid metal particles, or liquid metal.

47. The method according to any one of the preceding claims, wherein multiple different regenerable hydrogen sorbent metallic materials that regenerate at different pressures and temperatures are utilized in series.

48. The method according to claim 47, wherein a first regenerable hydrogen sorbent metallic material in the series sorbs hydrogen to saturation or near saturation at a lower pressure and temperature than a second regenerable hydrogen sorbent metallic material in the series.

49. The method according to claim 47, wherein the first regenerable hydrogen sorbent metallic material comprises tantalum and the second regenerable hydrogen sorbent metallic material comprises titanium.

50. An apparatus for regenerative separation of hydrogen gas from a hydrogencontaining gas that comprises the hydrogen gas and other gas species, the apparatus comprising:(a) a regenerative hydrogen sorbent metallic material, the regenerative hydrogen sorbent metallic material being capable of selectively sorbing hydrogen from the hydrogencontaining gas;(b) means for feeding the hydrogen-containing gas to contact the regenerative hydrogen sorbent metallic material;(c) means for varying the temperature and / or the pressure to which the regenerative hydrogen sorbent metallic material is subject between a first temperature and / or firstpressure at which the hydrogen is sorbed into the regenerative hydrogen sorbent metallic material and a second temperature and / or second pressure at which the hydrogen is desorbed from the regenerative hydrogen sorbent metallic material;(d) means for releasing a gas stream with a reduced level of hydrogen gas; and (e) means for releasing a stream of purified hydrogen gas.

51. The apparatus according to claim 50, further comprising:a sorption vessel for containing the regenerative hydrogen sorbent metallic material; a desorbing vessel operatively connected to the sorbing vessel;means for moving the regenerative hydrogen sorbent metallic material with sorbed hydrogen from the sorption vessel to the desorbing vessel; andmeans for moving the regenerative hydrogen sorbent metallic material depleted of hydrogen from the desorbing vessel to the sorbing vessel.

52. The apparatus according to claim 50 or 51 in combination with means for the production of hydrogen gas and / or hydrocarbon dehydrogenation.

53. The apparatus according to claim 52, further comprising a hydrogen production catalyst and / or hydrocarbon dehydrogenation catalyst and means for feeding a feedstock for hydrogen production and / or hydrocarbon dehydrogenation to contact the hydrogen production catalyst and / or hydrocarbon dehydrogenation catalyst.

54. The apparatus according to claim 53, further comprising a process vessel for containing the regenerative hydrogen sorbent metallic material and the hydrogen production catalyst and / or hydrocarbon dehydrogenation catalyst.

55. The apparatus according to claim 54, further comprising two or more process vessels arranged in parallel.

56. The apparatus according to any one of claims 50 to 55, wherein the regenerable hydrogen sorbent metallic material comprises an alkali metal, alkaline metal, lanthanide metal, and / or transition metal or alloys.

57. The apparatus according to claim 56, wherein the transition metal is a metal selected from the group consisting of Ti, Ta, V, Nb, Ru, Pd, La, Ce and Zr.

58. The apparatus according to claim 56, wherein the alkali / alkaline / lanthanide / transition metal is alloyed with one or more alloying elements selected from the group consisting of V, Nb, Ta, Ti, Zr, La, Ce, Al, Fe, Mg, Pd, Ag, Ni and Ru.

59. The apparatus according to claim 56, wherein the alkali / alkaline / lanthanide / transition metal is alloyed with one or more elements to form an alloy selected from the group consisting of Pb-Li, Al-Cu, Cu-Li, Al-Li, Al-Mg, Al-Si-Cu, Ti-AI, Ti-La, Ce-Ni, and La-Ni.

60. The apparatus according to any one of claims 50 to 57, wherein the regenerable hydrogen sorbent metallic material is a Ti alloy selected from the group consisting of commercial grade G1 to G9 Ti alloys, preferably from the group consisting of commercial grade G1 and G2 grade Ti alloys.

61. The apparatus according to any one of claims 50 to 60, wherein the regenerable hydrogen sorbent metallic material is in the form of solid metal mesh and filaments, solid metal fragments, solid metal particles, or liquid metal.

62. The apparatus according to any one of claims 50 to 61 , further comprising multiple different regenerable hydrogen sorbent metallic materials that regenerate at different pressures and temperatures arranged in series.

63. The apparatus according to claim 62, comprising a first regenerable hydrogen sorbent metallic material in the series capable of sorbing hydrogen to saturation or near saturation at a lower pressure and temperature than a second regenerable hydrogen sorbent metallic material in the series.

64. The apparatus according to claim 63, wherein the first regenerable hydrogen sorbent metallic material comprises tantalum and the second regenerable hydrogen sorbent metallic material comprises titanium.

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