Apparatus and process for activating ammonia decomposition catalysts

Abstract

To provide an apparatus and process for ammonia cracking catalyst activation.SOLUTION: An apparatus and process for the activation of catalyst material utilized in ammonia cracking can include an initial use of hydrogen and heat to perform an initial stage of catalyst activation and a subsequent use of ammonia and heat to perform a subsequent state of catalyst activation. The subsequent use of ammonia can be configured so that different catalytic material at different plant elements are activated in a pre-selected sequence to provide activation of the catalytic material utilized in different plant elements. Some embodiments can be configured to avoid excess temperatures that can be detrimental to equipment that can be positioned upstream of a furnace in some embodiments while also avoiding sintering of the catalytic material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0002] ,

[0001] Cross - reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 596,320, filed on November 6, 2023.

[0002] The present invention relates to a process and apparatus for the activation of catalyst materials utilized in ammonia decomposition plants and processes.

Background Art

[0003] Ammonia can be decomposed to produce hydrogen. Examples of processes that can be used to decompose ammonia can be understood from U.S. Patent Application Publication No. 2023 / 0242395 and International Publication Nos. 2022 / 265647, 2022 / 265648, 2022 / 265649, 2022 / 265650, 2022 / 265651, and pending U.S. Patent Applications Nos. 17 / 990,832, 17 / 990,823, 17 / 990,817, and 17 / 990,815.

Summary of the Invention

[0004] The ammonia decomposition process can involve the use of a catalyst material that aids in the decomposition of ammonia into hydrogen gas and nitrogen gas. The activation of the catalyst can depend on the formulation of the catalyst. Activation typically starts at a somewhat low temperature and increases towards a higher final temperature. The final temperature generally depends on the active metal species on the catalyst. For example, ruthenium (Ru) catalysts typically use a lower final activation temperature (e.g., less than 350°C), and nickel (Ni) catalysts often require a higher final activation temperature (e.g., greater than 350°C). Ru catalysts can also have more stringent requirements regarding the temperature increase and holding time for catalyst activation compared to Ni catalysts.

[0005] Andrew, SP (1981), Theory and practice of the formulation of heterogeneous catalysts. Chemical Engineering Science, 36(9), 1431-1445, discloses that activation of catalytic materials may involve exposing the catalytic material to a combination of a higher temperature environment (e.g., application of heat) and exposure to a reducing agent. Twigg, MV (1996). Catalyst Handbook (2nd ed.). London: Manson Publishing Ltd. ("Twigg") discloses that hydrogen is a commonly used reducing agent. Twigg also discloses that catalyst activation processes are carried out to reduce the precursor metal oxide of a supported metal catalyst to a metal catalyst microcrystal so that the catalyst is activated and can provide a change in the reaction mechanism that can help reduce the activation energy or facilitate a chemical reaction.

[0006] It has been identified that catalysts used in ammonia decomposition can be shipped in an oxidized, semi-oxidized, or at least partially passivated state that may require activation before use in ammonia decomposition. As described above, activation of catalyst materials may involve the use of processes in which the catalyst material is exposed to a reducing environment such as hydrogen-containing gas and heat for activation (e.g., removing oxides, removing an oxide layer surrounding or covering the internal catalyst metal material, removing a passivation layer surrounding or covering the internal catalyst metal material). Conventionally, activation would be carried out using hydrogen mixed with an inert gas such as nitrogen (see, for example, Twigg, MV (1996). Catalyst Handbook (2nd ed.). London: Manson Publishing Ltd.).

[0007] However, we have identified that the activation of catalyst materials that may be located in the furnace used for ammonia decomposition (e.g., located in the furnace tubes through which ammonia can be heated and decomposed in the furnace to form hydrogen (H2) and nitrogen (N2)) may require very high temperatures (e.g., above 500°C or above 600°C (e.g., 450°C-700°C, 550°C-675°C, 500°C-700°C, etc.)). We have identified that such high temperatures in the furnace during the long-duration catalyst activation process may require very high temperatures (e.g., above 500°C or above 600°C (e.g., 450°C-700°C, 550°C-675°C, 500°C-700°C, etc.)). It has been identified that some types of front-end heat exchangers disclosed in Patent No. 17 / 990,815 may exceed their design temperature unless they are made of special materials that can withstand very high temperatures, due to how the reducing agent and heat can be recirculated through the reactor and furnace for the activation of the catalytic material. However, utilizing such special equipment can be detrimental to the procurement of such equipment and results in increased costs, delays in production or installation, and increased special maintenance work and / or maintenance costs.

[0008] For example, the use of more specialized equipment may increase safety risks due to increased ratings of different metals or equipment, which can introduce an increase in items requiring maintenance supervision and monitoring. Avoiding or minimizing the use of such equipment may help avoid this increased safety risk and the additional maintenance activities of these types that would be utilized to account for that increased risk.

[0009] We have identified that such a high-temperature profile for catalyst activation in an ammonia decomposition unit configured to implement an ammonia decomposition process can be avoided, allowing the use of front-end equipment rated for lower temperatures. We have identified that such a feature may help provide improved catalyst material activation while offering improved operational efficiency and flexibility. We also believe that embodiments may help make ammonia decomposition more economically attractive through the use of more environmentally friendly ammonia products (e.g., ammonia produced via renewable energy sources and / or in conjunction with the use of carbon capture technologies), thereby also obtaining an increase in environmentally friendly ammonia production and ammonia decomposition for hydrogen production.

[0010] In some embodiments, processes and apparatus for catalytic activation of an ammonia decomposition apparatus may include utilizing hydrogen as a reactant and heat through a furnace to perform an initial first low-temperature phase of catalytic activation over a first catalytic activation period. This initial first low-temperature activation may include periodically increasing the temperature and / or hydrogen concentration until the first catalytic activation phase is satisfied, in some implementations. After it is detected that the first initial catalytic activation phase has been performed, a second high-temperature catalytic activation phase may be performed over a second catalytic activation period. This second phase may include the use of ammonia as a reagent and the use of a higher second temperature profile. This second phase may be combined with the exhaust of a hydrogen reactant fluid before or during the use of ammonia as a reactant for the second high-temperature catalytic activation phase and / or after such exhaust has been performed to remove the hydrogen reactant fluid. In some embodiments, the second phase, the high-temperature catalyst activation phase, may occur immediately after the first phase, so that the second phase is initiated immediately after the completion of the first initial low-temperature phase (for example, the second high-temperature phase may be initiated immediately after the first phase is detected to be complete, via the detection of a specific temperature and / or hydrogen content associated with the completion of the process of the initial low-temperature first catalyst activation phase).

[0011] In some embodiments, the process may be implemented to help control the temperature within a unit of the ammonia decomposition process so that the furnace experiences the highest temperature, and the upstream reactors and heat exchangers upstream of the furnace experience lower temperatures within a pre-selected temperature profile, thereby helping to avoid exposing the equipment to temperatures higher than what the equipment is experiencing would be evaluated (e.g., the temperature may not exceed 350°C, may be between 300°C and 400°C, or may not exceed 550°C). For example, several heat exchangers may have different temperature ratings, and the temperature control that may be provided by the catalyst activation treatment of the embodiment and the equipment configured to utilize such a process may be configured so that different heat exchanger equipment is kept within the temperature ratings of these heat exchanger equipment. Such temperature ratings may vary from 200°C to 690°C for different heat exchangers in some embodiments (e.g., one or more preheating heat exchangers may have temperature ratings in the range of 200°C to 325°C, while one or more other heat exchangers have temperature ratings in the range of 325°C to 690°C).

[0012] In some implementations, the catalyst activation provided may result in the catalyst material in the upstream portion of the furnace being activated first, followed by the catalyst material in a second reactor, even though this second reactor is located between the first reactor and the furnace. The catalyst activation provided may then result in the activation of the catalyst material in the first reactor before the catalyst material in the downstream portion of the furnace is finally activated. This type of stepwise activation helps provide a well-timed catalyst activation process that can also help avoid sintering of the catalyst material, while simultaneously helping to avoid high-temperature profiles in the upstream reactor and upstream heat exchanger.

[0013] We have found, surprisingly, that the use of ammonia as a reactant in the second high-temperature phase of catalyst activation may help keep the front-end heat exchanger within a lower standard design temperature. The ammonia used in the second high-temperature phase of catalyst activation may, in some embodiments, be blended with nitrogen or used pure. It is intended that by injecting nitrogen (N2) to mix with ammonia, a pre-selected flow rate of the second reactant and a desired flow rate to obtain a pre-selected concentration of ammonia in the second reactant may be provided as the second reactant passes through the pre-reactor and tubes containing the catalyst material.

[0014] We have found that the use of ammonia (NH3) during catalyst activation can also provide a cooling source for the entire system during catalyst activation (e.g., sensible heat, latent heat, and endothermic reactions of ammonia decomposition forming nitrogen and hydrogen during catalyst activation with ammonia as a reactant), which can reduce the demand for other cooling media / equipment during catalyst activation (e.g., load saving for cooling water towers or air coolers).

[0015] In some embodiments, the ammonia feed rate used during catalyst activation can be significantly lower than the design rate used for ammonia decomposition to produce hydrogen after the catalyst material is activated. Furthermore, a larger amount of conversion can be carried out across upstream reactors during catalyst activation. Since most of the ammonia can be utilized in the second catalyst activation phase, so that ammonia is converted in the upstream pre-reactors during the use of the high-temperature second catalyst activation phase, the temperature in the furnaces downstream of those reactors can rise rapidly to the desired activation temperature because there is little to very little (or possibly no) endothermic heat from the ammonia decomposition reaction that consumes the heat generated by the furnace burners during the catalyst activation process. Surprisingly, we have found that this effect can result in improved catalyst activation that can also be carried out more quickly (for example, by reducing the downtime associated with catalyst activation for ammonia decomposition treatment, the activation process can be carried out much faster, allowing catalyst activation to be more flexible, efficient, and rapid).

[0016] We also found that embodiments can enable the use of several catalyst materials having significantly higher final activation temperatures in conjunction with other catalyst materials having lower final activation temperatures. For example, in some embodiments, catalyst materials having activation temperatures above 600°C (e.g., 650°C, 600°C to 700°C, etc.) can be used with other catalyst materials having fully activated temperatures of 400°C or less, 350°C or less, or 300°C to 400°C.

[0017] In a first embodiment, the process for catalyst activation for ammonia decomposition includes feeding a first reactant containing hydrogen to at least one prereactor located upstream of the furnace, which has at least one tube in the radiating section of the furnace, such that the first reactant passes through the catalyst material of at least one prereactor and then through the catalyst material of at least one tube in the radiating section of the furnace. In response to detecting a first level of catalyst activation, the feeding of the first reactant can be stopped, and a second reactant containing ammonia can be started to feed to at least one prereactor and at least one tube in the radiating section of the furnace, thereby passing through the catalyst material of at least one prereactor and then through at least one tube in the radiating section of the furnace to fully activate the catalyst material of at least one tube.

[0018] In some embodiments, the concentration of hydrogen in the first reactant can be controlled to be within a pre-selected concentration range. For example, the first reactant may include a mixture of nitrogen and hydrogen, and the hydrogen concentration may be in the range of 10 mole percent (mol%) and 20 mol%, or in the range of greater than 0 mol% and less than or equal to 25 mol%. The hydrogen concentration may be adjusted during the first catalyst activation phase so that the hydrogen concentration is adjusted over time within a pre-selected range of preferred concentrations.

[0019] Furthermore, the concentration of ammonia in the second reactant can be controlled to be within a pre-selected concentration range. For example, the second reactant may contain a mixture of nitrogen and ammonia, and the ammonia concentration may be in the range of 10 mole percent (mol%) and 20 mol%, or in the range of greater than 0 mol% and less than or equal to 25 mol%. The ammonia concentration may be adjusted during the second catalytic activation phase so that the ammonia concentration is adjusted over time within a pre-selected preferred concentration range. Also, since ammonia is utilized in the second catalytic activation phase, hydrogen and nitrogen may be formed during the activation process and may be present together with the ammonia and nitrogen in the second reactant.

[0020] In some embodiments, the first level of catalytic activation may be determined based on a pre-selected set of criteria. The criteria may include a hydrogen temperature profile and / or concentration profile. The criteria may also include (or alternatively) a pre-selected period of time.

[0021] In a second embodiment, the feeding of the first reactants and the feeding of the second reactants may be carried out such that the catalyst material in the upstream portion of at least one tube is fully activated, then the catalyst material in at least one pre-reactor is fully activated, then after the catalyst material in at least one pre-reactor is fully activated, and after the catalyst material in the upstream portion of at least one tube is fully activated, the catalyst material in the downstream portion of at least one tube is fully activated. In other embodiments, the process may be implemented such that alternative activation sequences of different catalyst materials may be carried out instead.

[0022] In a third embodiment, the feeding of the second reactant containing ammonia may be carried out such that the catalyst material in the downstream portion of at least one tube is fully activated last. For example, the catalyst material in the downstream portion of at least one tube may contain iron (Fe) and / or nickel (Ni) and may be activated last after the upstream catalyst material layer in the furnace tube and one or more pre-reactors containing ruthenium (Ru) have been activated.

[0023] In a fourth embodiment, the process may include mixing nitrogen with the ammonia of the second reactant such that the second reactant has ammonia at a pre-selected ammonia concentration and / or the second reactant has a pre-selected flow rate.

[0024] In a fifth embodiment, the process may include mixing nitrogen with the hydrogen of the first reactant such that the first reactant has hydrogen at a pre-selected hydrogen concentration and / or the first reactant has a pre-selected flow rate.

[0025] In a sixth aspect, at least one pre-reactor can include a plurality of pre-reactors including a first pre-reactor and a second pre-reactor. The first pre-reactor can have a catalyst material within a vessel of the first pre-reactor, and the second pre-reactor can have a catalyst material within a vessel of the second pre-reactor. The second pre-reactor can be downstream of the first pre-reactor such that the second pre-reactor is between at least one tube of the furnace and the first pre-reactor.

[0026] The feeding of the first reactant can be performed as follows: (a) the catalyst material in the upstream portion of at least one tube is fully activated, (b) the catalyst material of the second pre-reactor is fully activated, (c) the catalyst material of the first pre-reactor is fully activated. The feeding of the second reactant can be performed such that (d) the catalyst material in the downstream portion of at least one tube is fully activated. In some embodiments, the catalyst material in the downstream portion of at least one tube can have a higher activation temperature than the catalyst material in the upstream portion of at least one tube. The catalyst material in the downstream portion of at least one tube can, in some embodiments, similarly have a higher activation temperature than the catalyst material of the first pre-reactor. The catalyst material in the downstream portion of at least one tube can have a higher activation temperature than at least a portion of the catalyst material of the second pre-reactor.

[0027] In a seventh aspect, the feeding of the first reactant can also include recirculating the first reactant through at least one tube and at least one pre-reactor over a first period. The first period can be, for example, the first period of a first catalyst activation phase. This first period can be a preselected period defined by a set of preselected design criteria.

[0028] In the eighth aspect, the process may also include, in response to detecting a first level of catalyst activation, exhausting the first reactants while simultaneously beginning to feed the second reactants toward at least one pre-reactor and at least one tube. The exhaust may also be provided so as to exhaust (e.g., not recirculate) any second reactants ejected from at least one tube during the process of the second catalyst activation phase.

[0029] In the ninth embodiment, the process of the first embodiment may include one or more features of the second, third, fourth, fifth, sixth, seventh, and / or eighth embodiment in order to provide further embodiments. Other features may also be utilized in embodiments of the process. Examples of such other features are considered in relation to exemplary embodiments of the process provided herein.

[0030] In a tenth aspect, an apparatus for ammonia decomposition configured to facilitate catalyst activation is provided. Embodiments of the apparatus can be configured to utilize embodiments of a process for catalyst activation for ammonia decomposition. The apparatus can include a furnace having at least one tube containing a catalyst material within at least one tube for decomposition of ammonia. The catalyst material within the at least one tube can have an upstream portion of the catalyst material and a downstream portion of the catalyst material. At least one pre-reactor can be positioned upstream of the at least one tube. The at least one tube can be in fluid communication with the at least one pre-reactor. The apparatus can be sized and configured such that a first reactant can be fed to the at least one pre-reactor and the at least one tube such that the first reactant passes through the catalyst material of the at least one pre-reactor and then through the catalyst material of the at least one tube. Also, the apparatus can be sized and configured such that a second reactant can be fed to the at least one pre-reactor and the at least one tube such that, in response to detecting a first level of catalyst activation, the first reactant can be exhausted and the second reactant can pass through the catalyst material of the at least one pre-reactor and then through the at least one tube such that the second reactant completely activates at least a portion of the catalyst material of the at least one tube.

[0031] Embodiments of the apparatus can also include other elements and features. For example, embodiments can include a plurality of heat exchangers positioned upstream of the pre-reactor and / or one or more heat exchangers positioned between the pre-reactor and at least one tube of the furnace. As another example, embodiments can utilize pumps and / or compressors to facilitate a flow of fluid.

[0032] In an eleventh embodiment, the apparatus may be configured such that the feeding of the first reactant is carried out so that the upstream portion of the catalyst material in at least one tube is fully activated first, and then the catalyst material in at least one pre-reactor is fully activated. The second reactant may also be fed to at least one tube and at least one pre-reactor so that the downstream portion of the catalyst material in at least one tube is fully activated after the catalyst material in at least one pre-reactor has been fully activated and after the upstream portion of the catalyst material in at least one tube has been fully activated. For example, in some embodiments, the apparatus may be configured such that the feeding of the second reactant is carried out so that the downstream portion of the catalyst material in at least one tube is fully activated last.

[0033] In a twelfth aspect, at least one prereactor of the apparatus may include a plurality of prereactors. The plurality of prereactors may include a first prereactor having catalyst material in the vessel of the first prereactor, and a second prereactor having catalyst material in the vessel of the second prereactor. The second prereactor may be located downstream of the first prereactor, such that the second prereactor is located between at least one tube of the furnace and the first prereactor. The apparatus may be configured such that the feeding of the first reactants occurs such that (a) the upstream portion of the catalyst material in at least one tube is fully activated, (b) the catalyst material in the second prereactor is fully activated, and (c) the catalyst material in the first prereactor is fully activated. The feeding of the second reactants may occur such that (d) the catalyst material in the downstream portion of the catalyst material in at least one tube is fully activated. The downstream portion of the catalyst material in at least one tube may have a higher activation temperature than the catalyst material in the upstream portion of the catalyst material in at least one tube. The downstream portion of the catalyst material in at least one tube may also have a higher activation temperature than the catalyst material in the first pre-reactor, and the catalyst material in the downstream portion of at least one tube may also have a higher activation temperature than at least a portion of the catalyst material in the second pre-reactor.

[0034] In a thirteenth embodiment, the apparatus may include a reactant recirculation conduit arrangement positioned such that the first reactant can be recirculated from the outlet of at least one tube to at least one pre-reactor. In some embodiments, the reactant recirculation conduit may be positioned and configured such that a compressor can receive a portion of the first reactant output from at least one tube and compress it to recirculate the first reactant back to at least one tube of the pre-reactor and furnace.

[0035] In a fourteenth aspect, an apparatus for ammonia decomposition configured to promote catalyst activation may include a furnace having at least one tube, wherein the furnace contains a catalyst material in at least one tube for ammonia decomposition, and the catalyst material in at least one tube has a more active portion of the catalyst material that is more active than a less active portion of the catalyst material. At least one prereactor may be positioned upstream of at least one tube, and at least one tube may be in fluid communication with at least one prereactor. The apparatus may be sized and configured such that a first reactant can be fed to at least one prereactor and at least one tube such that the first reactant passes through the catalyst material of at least one prereactor and then through the catalyst material of at least one tube. The second reactant may be fed to at least one prereactor and at least one tube so that, in response to detecting a first level of catalyst activation, the first reactant can be exhausted, and the second reactant can be fed to at least one prereactor and at least one tube so that the second reactant can pass through the catalyst material of at least one prereactor to fully activate the less active portion of the catalyst material of at least one tube, and then pass through at least one tube. Embodiments of the apparatus may also include other features (e.g., recirculation conduits, heat exchangers, etc.).

[0036] In the fifteenth aspect, the apparatus of the tenth aspect or the apparatus of the fourteenth aspect may include one or more other features of the eleventh aspect, the twelfth aspect, and / or the thirteenth aspect to provide further embodiments. Other features may also be utilized in embodiments of the apparatus. Examples of such other features are considered in relation to exemplary embodiments of the apparatus provided herein.

[0037] In yet another embodiment of the apparatus and process, it is intended that only a single reactant containing ammonia (e.g., ammonia, ammonia mixed with nitrogen gas, etc.) may be used for catalyst activation. The ammonia used may be liquid ammonia that is vaporized, optionally mixed with nitrogen, and then passes through a pre-reactor and at least one tube having catalyst material inside, positioned within the radiation section of the furnace for the activation of the catalyst material. The activation of the catalyst material is carried out over a pre-selected period according to a pre-selected activation scheme, which can provide complete activation of all catalyst material within the temperature ratings of various instruments. Such activation may be provided through the use of recirculation of at least a portion of the ammonia, while adding additional liquid ammonia to the reactant feed to provide catalyst activation, and while controlling the temperatures of different pre-reactor / furnace tubes and heat exchangers to provide a sequence of catalyst activation, such that catalyst material having the highest activation temperature in the furnace tube is activated last, while other catalyst material is activated before catalyst material having the highest activation temperature in the furnace tube.

[0038] It should be understood that the embodiments of the process and apparatus can utilize various conduit arrangements and process control elements. Embodiments may utilize sensors (e.g., pressure sensors, temperature sensors, flow sensors, concentration sensors, etc.), controllers, valves, piping, and other process control elements. Some embodiments may utilize, for example, an automated process control system and / or a distributed control system (DCS). Various different conduit arrangements and process control systems can be used to satisfy a specific set of design criteria.

[0039] Further details, purposes, and advantages of this apparatus for activating catalytic materials used in ammonia decomposition, the process for activating catalytic materials used in ammonia decomposition, and methods for fabricating and using them will become apparent as the following description of its specific exemplary embodiments progresses.

[0040] Exemplary embodiments of our apparatus for activating catalytic materials used in ammonia decomposition, processes for activating catalytic materials used in ammonia decomposition, and methods for their preparation and use are shown in the drawings contained herein. It should be understood that similar reference letters used in the drawings may identify similar components. [Brief explanation of the drawing]

[0041] [Figure 1] Figure 1 is a block diagram of a first exemplary embodiment of an apparatus configured for ammonia decomposition, which is also configured to activate the catalytic material used in ammonia decomposition. An exemplary embodiment of the process for activating the catalytic material used in ammonia decomposition can also be understood from Figure 1. [Figure 2] Figure 2 is a flowchart illustrating an exemplary embodiment of a process for activating a catalytic material used in ammonia decomposition. A first exemplary embodiment of the apparatus for activating a catalytic material used in ammonia decomposition may implement this first exemplary embodiment of the process. [Modes for carrying out the invention]

[0042] Referring to Figures 1-2, the apparatus 1 configured for ammonia decomposition may include several process elements that receive ammonia (NH3) and decompose the ammonia to produce hydrogen gas and nitrogen gas. The formed hydrogen can then be separated from the nitrogen to produce a hydrogen stream 40.

[0043] For example, the supply of liquid ammonia 2 can be maintained at the ammonia storage temperature (e.g., -32°C, -25°C to -40°C, etc.) in a storage device (e.g., at least one ammonia storage tank). The stored ammonia, which can be stored as liquid ammonia, is removed from the storage device and supplied to pump P101, where the ammonia is supplied at a pre-selected supply pressure (e.g., 4.6 MPa, 4 MPa to 5 MPa, or other suitable supply pressure within the pre-selected supply pressure range) to produce a pressurized liquid ammonia flow 4. The pressurized supply flow 4 can be supplied to a preheating heat exchanger E271, which can preheat the pressurized supply of ammonia to produce a preheated liquid ammonia flow 6.

[0044] In some embodiments, the preheating heat exchanger E271 can utilize a heat transfer fluid which can be any suitable type of heat transfer fluid for preheating liquid ammonia to a pre-selected preheating temperature (e.g., a temperature of 40°C to 60°C, a temperature of 45°C, etc.). In some embodiments, the heat transfer fluid may be or may include glycol (e.g., a fluid having 55% by weight of ethylene glycol or propylene glycol). Alternatively, the preheating heat exchanger E271 may be (or also include) an electric heater which helps to ensure that the temperature of the heat transfer fluid supplied to the heat exchanger E271 as a heating medium is at a temperature sufficient to preheat the liquid ammonia to the desired temperature.

[0045] The preheated feed flow 6 can undergo further preheating to further heat and vaporize the ammonia feed via other preheating heat exchangers. For example, one or more other preheating heat exchangers such as heat exchangers E312, E311, E310, and E2102 can be used.

[0046] For example, the initially preheated ammonia feed stream 6 output from heat exchanger E271 can be further heated by heat exchange in heat exchanger E312 to generate a further heated liquid ammonia stream 8. Then, the further heated liquid ammonia in stream 8 can be evaporated via heat exchange in heat exchanger E311 to generate a gaseous ammonia or ammonia vapor stream 10. Then, the ammonia vapor in stream 10 can be superheated by heat exchange in heat exchanger E310 to generate a heated ammonia gas stream 12 at a pre-selected preheated ammonia gas temperature (e.g., 260°C, 240°C-280°C, etc.).

[0047] Next, the heated ammonia gas in flow 12 can be further heated by heat exchange in heat exchanger E2102 to generate a flow 14 of superheated ammonia gas at a pre-selected superheated ammonia gas temperature (e.g., 420°C, 400°C-450°C, etc.).

[0048] In connection with providing such preheating of ammonia gas, each heat exchanger E310, E311, E312, and E2102 may have a pre-selected temperature rating specified in consideration of the preheating conditions that a particular heat exchanger may experience during ammonia decomposition operation and the availability of equipment that can meet those conditions. For example, heat exchanger E312 may have a temperature rating of 100°C to 300°C, heat exchanger E311 may have a temperature rating of 175°C to 450°C, heat exchanger E310 may have a temperature rating of 330°C to 570°C, and heat exchanger E2102 may have a temperature rating of 300°C to 500°C. Other embodiments may have other heat exchangers utilizing other temperature profiles and other suitable temperature ratings.

[0049] In some embodiments, there may be a single heat exchanger E2102 for providing superheated ammonia gas. In other embodiments, heat exchanger E2102 may produce a superheated ammonia gas flow 14 by outputting a heated ammonia gas flow for supply to at least one other feed-preheat heat exchanger. In some implementations, there may also be at least one selective catalytic reactor (SCR) located downstream of heat exchanger E2102 or within the heat exchanger (e.g., within heat exchanger E2102) between heat exchanger E2102 and the second feed-preheat heat exchanger. In some embodiments, the heat transfer fluid that can be used as a heating medium for heat exchanger E2102 and / or other heat exchangers may be flue gas output from furnace F201 of apparatus 1.

[0050] Other embodiments can utilize different arrangements of preheating heat exchangers to generate a flow of superheated ammonia gas 14. For example, fewer or more heat exchangers can be used to provide the formation of superheated ammonia gas. The heat transfer fluid used for such heating can be any suitable heat transfer fluid that can function as a suitable heating medium for heating ammonia to form a flow of superheated ammonia gas 14.

[0051] The superheated ammonia gas in flow 14 can be fed to one or more pre-reactors upstream of furnace F201. The feed temperature of the superheated ammonia gas stream for feeding to one or more pre-reactors can be a pre-selected superheated ammonia gas feed temperature (e.g., 420°C, 400°C–500°C, 400°C–450°C, etc.). The feed pressure of the superheated ammonia gas stream can be a suitable pre-selected feed pressure that can be less than the pressure at which pump P101 outputs the pressurized liquid ammonia stream 4. For example, the pre-selected feed pressure of the superheated ammonia fed to one or more pre-reactors can be 4.3 MPa, 4 MPa–4.5 MPa, or other suitable pressures.

[0052] The upstream pre-reactor may include a first adiabatic reactor C141, or a first pre-reactor C141, which may have a catalyst bed within the reactor vessel. The catalyst bed may include a suitable catalyst material. For example, the catalyst material of the catalyst bed in the first adiabatic reactor C141 may be a ruthenium-based catalyst bed or a nickel-based catalyst bed. Other embodiments may use a first pre-reactor C141 that can alternatively utilize other catalyst materials or combinations of catalyst materials (e.g., a bed of iron-based catalyst material, a bed of catalyst material having a combination of nickel catalyst material and iron catalyst material, a catalyst material including a combination of an upstream layer of catalyst material and a downstream layer of a different catalyst material).

[0053] A portion of the ammonia gas can be decomposed as it passes through this catalyst bed in the first pre-reactor C141 to form a first pre-reactor output stream 16 of intermediate gas containing ammonia gas and several products of partially decomposed ammonia (e.g., nitrogen gas and hydrogen gas). In some embodiments, the mole fraction of ammonia in the gas passing through the first adiabatic reactor vessel C141 can decrease from about 100 mole percent (mol%) ammonia to about 90 mol% ammonia (e.g., about 10% of the ammonia can be decomposed as it passes through the first pre-reactor C141). In other embodiments, the mole fraction of ammonia may vary (e.g., 95 mol% to 90 mol% ammonia, or 95 mol% to 80 mol% ammonia, etc.).

[0054] The first pre-reactor output stream 16 of the intermediate gas can be output at a pre-selected temperature. This temperature may be, for example, about 360°C, 320°C to 380°C, or another preferred temperature. This intermediate stream can then be fed to a second pre-reactor C142, which may be, for example, a second adiabatic reactor C142.

[0055] In some embodiments, the first pre-reactor output flow 16 of the intermediate gas can be heated via a heat exchanger E2103 to generate a superheated intermediate gas flow 18, which is then fed to a second adiabatic reactor C142, which may also be another type of second pre-reactor. For example, the first pre-reactor output flow 16 of the intermediate gas can be heated to a pre-selected second pre-reactor feed temperature by passing through the heat exchanger E2103, and then the first pre-reactor output flow 16 is fed to the second adiabatic reactor C142. The second pre-selected second pre-reactor feed temperature may be, for example, 590°C, 450°C to 610°C, 550°C to 620°C, or other suitable feed temperatures. The intermediate gas preheating heat exchanger E2103 can utilize a suitable heat transfer fluid to provide the desired preheating (e.g., exhaust gas or flue gas from the furnace F201 or other heating medium).

[0056] The superheated intermediate gas flow 18 can be fed to a second pre-reactor C142 (e.g., a second adiabatic reactor C142). The second pre-reactor may also include a vessel having a bed containing catalyst material. The catalyst material in the second pre-reactor C142 may be the same catalyst material as in the first pre-reactor, or may include a different arrangement of catalyst material. For example, the second pre-reactor C142 may have a bed of catalyst material including an upstream layer of nickel-based catalyst and a downstream layer of ruthenium-based catalyst. Other embodiments may alternatively utilize different combinations of a single type of catalyst material, or catalyst material, or bed. For example, in some embodiments, the second pre-reactor C142 may utilize a bed of catalyst material including only iron-based catalyst, only ruthenium-based catalyst, or a combination of a downstream layer of nickel-based catalyst and / or iron-based catalyst and an upstream layer of ruthenium-based catalyst.

[0057] The superheated intermediate gas can be passed through a second pre-reactor for further preliminary decomposition of the ammonia in the intermediate gas to produce a partially decomposed ammonia gas furnace feed stream 20. The mole fraction of ammonia in the gas output from the second pre-reactor C142 can be a pre-selected furnace feed concentration. For example, the mole fraction of ammonia in the furnace feed stream 20 can be 0.6 (e.g., 60 mol% ammonia) or 55 mol% to 75 mol% ammonia.

[0058] When ruthenium-based catalysts are used in both the first pre-reactor C141 and the second pre-reactor C142, the same type of catalyst may be used in both reactors, or different ruthenium-based catalysts may be used. The types of catalyst materials used in the first and second pre-reactors may also be adapted to take into account different design criteria or operational objectives. In some embodiments, the catalyst bed of the first pre-reactor C141 may be configured to provide lower levels of ammonia decomposition compared to the catalyst bed of the second pre-reactor C142, which is located downstream of the first pre-reactor C141 and upstream of the furnace F201.

[0059] In some configurations, at least one of the pre-reactors can utilize a less active catalyst for promoting ammonia decomposition, compared to a more active catalyst that has higher activity for promoting ammonia decomposition. For example, a ruthenium-based catalyst may be a more active catalyst, while a nickel-based or iron-based catalyst may be a less active catalyst. The less active catalyst may also have a higher full activation temperature than the more active catalyst.

[0060] In other embodiments, there may be only a single pre-reactor (e.g., only pre-reactor C141 or C142). In such embodiments, the operating temperature of the single pre-reactor, the catalyst material used in the pre-reactor, and the size of the pre-reactor may be adjusted in consideration of its use in providing a feed of partially decomposed ammonia as a furnace feed stream 20 for further decomposition in one or more tubes of furnace F201. In such configurations, the feed temperature of the superheated ammonia gas stream for feed to the pre-reactor may be a pre-selected superheated ammonia gas feed temperature, which may be higher than that which may be selected for use in arrangements having multiple pre-reactors (e.g., temperatures of 450°C to 550°C, 475°C to 600°C, etc.) for processing the ammonia inside to output the partially decomposed ammonia in the furnace feed stream 20.

[0061] The partially decomposed ammonia in the furnace feed flow 20 may be heated by heat exchange in the heat exchanger E305 before being fed as a furnace feed flow 22 preheated at a pre-selected furnace feed temperature and pressure. The heating medium used in the heat exchanger E305 may be any suitable fluid (e.g., hydrogen product gas and / or nitrogen product gas output from furnace F201, or other suitable heat transfer fluid). The pre-selected furnace feed pressure may be a suitable feed pressure (e.g., a pressure of 3.8 MPa, a pressure of 3 MPa to 4.1 MPa, etc.). The pre-selected furnace feed temperature may also be a suitable feed temperature (e.g., a temperature of 300°C to 500°C, 450°C, 500°C, etc.). In some embodiments, the inlet feed temperature of the preheated furnace feed flow 22 may be limited to a pre-selected furnace feed temperature (e.g., 500°C, 400°C–500°C, etc.) to help limit the inner wall temperature of one or more ammonia decomposition tubes through which the ammonia in the flow of the preheated furnace feed flow 22 can pass to undergo decomposition in the furnace F201.

[0062] The heat exchanger E305 may also have a pre-selected temperature rating in some embodiments. For example, the heat exchanger E305 may have a temperature rating of 500°C to 700°C in some embodiments. The selected temperature rating for the heat exchanger E305 may be specified taking into account the preheating conditions that this particular heat exchanger is expected to experience during ammonia decomposition operation and the availability of equipment that can meet those conditions. Other embodiments may have other heat exchangers with other suitable temperature ratings that utilize other temperature profiles.

[0063] The furnace F201 may include a combustion chamber and one or more catalyst-filled tubes that may be located in the radiating section 89 of the furnace F201, which may be considered a furnace reactor or a primary ammonia decomposition reactor. A preheated furnace feed flow 22 may pass through one or more catalyst-filled tubes in the radiating section 89 of the furnace F201 and undergo ammonia decomposition within the catalyst-filled tubes. At least one fuel may be burned in the combustion chamber to generate flue gas through the combustion of the fuel to heat the preheated furnace feed flow 22 containing ammonia, as well as hydrogen and nitrogen (for example, through the pre-decomposition of ammonia which may be provided by one or more pre-reactors), thereby facilitating the decomposition of ammonia passing through one or more catalyst-filled tubes of the furnace F201.

[0064] The catalyst material within the furnace F201 (for example, catalyst material in one or more catalyst-filled tubes, which may be filled with catalyst material or arranged with catalyst material) may be positioned to help increase the amount of ammonia decomposition that can be carried out using the heat from the furnace burner in the furnace combustion chamber by reducing the load required to heat the partially decomposed flow to the reaction temperature for ammonia decomposition.

[0065] As described above, the furnace F201 may include a combustion chamber that burns flue gas and at least one fuel to generate heat, thereby promoting ammonia decomposition within the furnace F201. In some configurations, a flow 62 of air or another oxidant (e.g., oxygen-rich air) may pass through a forced draft fan K212 before being preheated by heat exchange in an oxidant preheat exchanger E2141 to generate a preheated oxidant flow 64. The preheated oxidant flow 64 may be mixed with a flow 70 of fuel (e.g., natural gas, hydrogen gas, a mixture of natural gas and hydrogen) supplied to the burner (not shown) of the furnace F201 for combustion of fuel in the furnace's combustion chamber. Preheating the oxidant may help reduce the amount of fuel required to facilitate combustion to generate the desired level of heat for ammonia decomposition.

[0066] One or more tubes within the radiation section 89 of furnace F201 may be filled with at least two types of ammonia decomposition catalysts in a plurality of different layers, the plurality of different layers including an upstream layer located at and / or adjacent to the inlet of furnace F201 and a downstream layer located at and / or adjacent to the outlet of the furnace, through which decomposed ammonia products can be discharged. In some intended embodiments, one or more tubes may also include at least one intermediate layer of catalyst material between the upstream layer and the downstream layer of catalyst material. In other embodiments, there may only be an upstream layer and a downstream layer of catalyst material.

[0067] The upstream and downstream catalyst materials in one or more tubes within the radiation section 89 of furnace F201 may have different activation temperature requirements. For example, the upstream layer may have a lower activation temperature requirement than the downstream catalyst material layer. In some embodiments, the catalyst material in the upstream layer may also be less active than the downstream layer (for example, the upstream layer may be a less active portion of the catalyst material in furnace F201). In other embodiments, the catalyst material in the upstream layer may be more active than the downstream layer (for example, the upstream layer may be a more active portion of the catalyst material in furnace F201, which is more active than the less active portion of the catalyst material in furnace F201).

[0068] For example, a ruthenium-based catalyst can be used in the first upstream catalyst material layer in each tube of furnace F201 so that the metal temperature can be maintained within a pre-selected design limit (e.g., a design limit of approximately 660°C, a design limit of 600°C to 700°C, etc.) with a faster reaction rate. A second downstream catalyst material layer in one or more tubes of furnace F201, downstream of the first catalyst material layer, may include a lower-cost but less active nickel-based or iron-based catalyst (e.g., a Ru-based catalyst in the first upstream layer, which is the less active part of the furnace's catalyst material, an example of the less active part of the furnace's catalyst material).

[0069] In other embodiments, the first upstream catalyst material layer and the second downstream catalyst material layer in one or more tubes of the furnace F201 may utilize other types of catalyst materials. In some configurations, the upstream catalyst material layer may have a lower activation temperature than the downstream catalyst material layer, while in other configurations, the upstream catalyst material layer may have a higher activation temperature than the downstream layer. In yet another embodiment, one or more tubes of the furnace F201 may have a single type of catalyst material within the tube.

[0070] The furnace F201 can be operated by the combustion of fuel to heat ammonia in a preheated furnace feed stream 22, which is fed into one or more tubes to decompose ammonia and produce hydrogen and nitrogen gases. The furnace F201 can output at least one stream 24 of decomposed gas, which can exit the radiation section 89 of the furnace F201 at a pre-selected outlet temperature (e.g., 640°C, 600°C–700°C, 620°C–750°C, etc.). The decomposed gas output from the furnace F201 can be fed into the heat exchanger E305 as a heating medium to preheat the furnace feed stream 20 output from the second pre-reactor C142. The cooled decomposed gas can be output from the heat exchanger E305 at a pre-selected cooling temperature. Such a temperature can be lower than the temperature at which the gas was output from the furnace F201 (e.g., 500°C–600°C, 450°C–550°C, etc.). The cooled decomposed gas can be fed to another heat exchanger and output from heat exchanger E305 to undergo additional cooling before being fed to hydrogen recovery unit U501.

[0071] For example, the cooled flow 26 of the decomposed gas is output from heat exchanger E305 and fed to heat exchanger E310, and then fed to other heat exchangers E311 and E312, where it is used as a heating medium to heat the ammonia passing through the other heat exchangers E311 and E312, and the decomposed gas can be cooled toward the desired feed temperature of the hydrogen recovery unit.

[0072] For example, the cooled decomposed gas in flow 26 can be supplied to heat exchanger E310 to provide heating for superheating the ammonia gas, thereby further lowering the temperature of the decomposed gas and cooling it. The decomposed gas flow 28 supplied from heat exchanger E310 to heat exchanger E311 can be output from heat exchanger E310 to provide a load to evaporate the further heated liquid ammonia supplied to heat exchanger E311 via flow 8, thereby further lowering the temperature of the decomposed gas. The decomposed gas flow 30 supplied to heat exchanger E312 can be output from heat exchanger E311 to provide a load to further heat the heated pressurized liquid ammonia in flow 6, thereby further lowering the temperature of the decomposed gas.

[0073] Heat exchangers E305, E310, E311, and E312 are depicted in the exemplary embodiment of Figure 1 as individual shell-and-tube style heat exchangers, with ammonia passing through the tubes and the decomposed gases passing through the shell side. However, this arrangement can be reversed. Alternatively, these heat exchangers can be combined to form a single shell-and-tube style heat exchanger, or different styles of heat exchangers can be used in practice.

[0074] The decomposed gas flow 32 can be output from heat exchanger E312 to supply the hydrogen recovery unit U501 at a pre-selected supply temperature for the hydrogen recovery unit. For example, heat exchanger E312 can output the cooled decomposed gas to heat exchanger E323, which can further cool the decomposed gas to a pre-selected supply temperature for the hydrogen recovery unit by using a refrigerant or coolant (e.g., cooling water) to facilitate further cooling of the decomposed gas as desired. The sufficiently cooled decomposed gas can then be output from heat exchanger E323 to supply the hydrogen recovery unit U501 as a hydrogen recovery supply flow 34.

[0075] In some embodiments, the hydrogen recovery unit U501 may be configured as a pressure fluctuation adsorption (PSA) system. In other embodiments, a different type of adsorption system may be used (e.g., vacuum fluctuation adsorption, temperature fluctuation adsorption, etc.). In yet another embodiment, a different type of hydrogen separation system may be used to separate the hydrogen from the decomposed gas from the nitrogen gas and other components of the decomposed gas.

[0076] The hydrogen recovery unit U501 can separate hydrogen from other components of the decomposed gas and provide a hydrogen product stream 40 that can contain hydrogen at a desired purity concentration (e.g., 99 mol% hydrogen, 99 mol% to 100 mol% hydrogen, etc.).

[0077] The hydrogen recovery unit U501 can also output a flow 42 which may be an off-gas containing nitrogen gas, residual hydrogen gas, and residual ammonia gas. In some embodiments, the flow 42 may also contain other fewer components.

[0078] The hydrogen gas in flow 40 may be supplied to a hydrogen liquefaction unit (not shown) to produce liquid hydrogen. In other embodiments, the hydrogen gas flow 40 may be supplied to at least one downstream plant process for use of the hydrogen gas.

[0079] The off-gas flow 42 may be supplied to the combustion chamber of the furnace F201 as a fuel flow 60 for internal combustion. Alternatively (or additionally), the flow 42 may be divided into multiple parts, one of which may be used as a fuel flow. In yet another embodiment, the flow 42 may be divided, and none of the divided parts may be supplied to the furnace F201 as a fuel flow 60 (for example, combustion in the furnace F201 may be provided only through fuel from the fuel flow 70).

[0080] For example, the flow 42 can be divided such that a first portion 44 of the off-gas in the flow 42 is heated by heat exchange in the heat exchanger E2112 to produce a heated off-gas flow 60, which is then supplied to one or more burners in the furnace F201 together with an air supply 64 and optionally a fuel flow 70 (e.g., a natural gas supply flow). A minimum amount of natural gas or other suitable fuel for the fuel flow 70 can be used as trim fuel to provide the fuel balance required in the ignition section of the combustion chamber to replenish the ammonia and / or hydrogen present in the first portion 44 of the off-gas supplied to the furnace F201.

[0081] A second portion 46 of the off-gas 42 (if used) can be sent to a compression system K681 (e.g., a multi-stage compressor, compressor assembly, etc.) for compression. The compression system K681 may have multiple stages with intercoolers between each stage, along with an aftercooler following the final stage. Heat can be recovered from the compressed gas in the intercoolers and aftercoolers by heat exchange with a heat transfer fluid. Heat can also be recovered from the lubricating oil and, if a positive displacement compression unit is used, from the cylinders of the compression unit via the heat transfer fluid.

[0082] The intercooler and aftercooler that can be used are shown by a single heat exchanger E6816 in Figure 1, which can recover heat from a compressed off-gas flow 48 by heat exchange with a heat transfer fluid flow 52 to produce a cooled, compressed off-gas flow 50 and a heated heat transfer fluid flow 54 that can be used in another process or heat exchanger (e.g., heat exchanger E271). For example, a heat transfer fluid heated in a cooler E323, as well as in the intercooler and aftercooler E6816, can be used to provide a load for preheating liquid ammonia by heat exchange in a heat exchanger E271.

[0083] The cooled and compressed off-gas in flow 50 can be fed to a phase separator C6816 where condensates can be removed as flow 56. The compressed off-gas can then be recycled as flow 58 to the hydrogen recovery unit U501 to recover further hydrogen. In other embodiments, this process can be operated without the use of the compression system K681 and a second portion 46 of the off-gas that is processed to be returned to the hydrogen recovery unit U501 for recycling. Such embodiments may result in lower hydrogen recovery in the hydrogen recovery unit U501. While lower hydrogen recovery may result in fewer hydrogen gas products, lower hydrogen recovery may still be desirable because it reduces the carbon intensity (CI) of the process, as the off-gas contains more hydrogen, thereby reducing the need for natural gas as trim fuel and lowering carbon dioxide emissions. This type of arrangement may also provide lower overall power consumption due to the non-use of the compression system K681.

[0084] Furnace F201 can discharge at least one flow 72 of flue gas. The discharged flue gas can be at a pre-selected flue gas discharge temperature (e.g., a temperature of 650°C to 700°C, a temperature of approximately 686°C, etc.). The flue gas flow 72 can pass from the radiative section 89 of furnace F201 to the convection section 90 of furnace F201, where the flow 72 can function as a heating medium as described above. For example, the flue gas discharged from furnace F201 can provide a load for heating the intermediate gas from flow 16 in heat exchanger E2103, thereby lowering the temperature of the flue gas which can then be discharged as a heating medium flow 74 for supply from heat exchanger E2103 to heat exchanger E2012, and can provide a load for further heating the heated ammonia gas from flow 12 in heat exchanger E2102, thereby further lowering the temperature of the flue gas. The flue gas may be routed to provide a heating load in the counter-flow direction of the feed gas flow into the radiating section of furnace F201.

[0085] The cooled flue gas can be output from heat exchanger E2102 as a further cooled flue gas flow 76 to be supplied to heat exchanger E2142, providing a load to heat the air from flow 62 in heat exchanger E2142, thereby further lowering the temperature of the flue gas. Further cooled flue gas can be output from heat exchanger E2142 as flow 78 to be supplied to heat exchanger E2112, providing a load to preheat the first portion 44 of the off-gas flow 42 in heat exchanger E2112, thereby further cooling the flue gas.

[0086] The cooled flue gas can be output as flow 80 from the convection section 90 of the direct-fired tube furnace F201 at a pre-selected flue gas output temperature (e.g., a temperature above 100°C, a temperature of about 121°C, a temperature above the condensation point of water, a temperature above a pre-selected acid dew point to avoid acid condensation, etc.). In some embodiments, the cooled flue gas can be passed through an induction draft fan K211 for discharge as exhaust flow 82. Embodiments may be configured to utilize an economical amount of practical energy from the flue gas for exhausting the cooled flue gas into the atmosphere. In some embodiments, the flue gas may first undergo other treatments (e.g., carbon dioxide capture, particulate removal, etc.) depending on the composition of the flue gas.

[0087] In some embodiments, oil from a boil-off gas compressor (not shown) used with an ammonia storage tank (not shown) may be present in the liquid ammonia in amounts up to approximately 5 ppm at either the site where ammonia is generated or where ammonia is decomposed, or at any intermediate point between these two locations. In some configurations, it may be desirable to remove the oil before the ammonia is exposed to the catalyst in the pre-reactor and / or furnace F201. The oil may be removed by passing the ammonia through an activated carbon bed or via one or more other types of oil removal treatment units. If oil is to be removed from ammonia, the oil removal unit (not shown) may be located in flow 2 (e.g., in the feed line to pump P101), in flow 4 (e.g., between pump P101 and heat exchanger E271), in flow 6 (e.g., between heat exchanger E271 and heat exchanger E312), in flow 8 (e.g., between heat exchangers E312 and E311), in flow 10 (e.g., between heat exchangers E311 and E310), or at any other suitable location upstream of the pre-reactor and furnace F201.

[0088] One or more tubes of furnace F201, and / or pre-reactors upstream of furnace F201, may contain catalytic materials to promote ammonia decomposition. These catalytic materials may include, for example, metals to promote the ammonia decomposition reaction that decomposes ammonia into nitrogen and hydrogen gases. Metals that may be included in the catalytic materials may include transition metals such as those in Group 6 of the periodic table (e.g., chromium (Cr) and molybdenum (Mo)); Group 8 of the periodic table (e.g., iron (Fe), ruthenium (Ru), and osmium (Os)); Group 9 of the periodic table (e.g., cobalt (Co), rhodium (Rh), and iridium (Ir)); Group 10 of the periodic table (e.g., nickel (Ni), palladium (Pd), and platinum (Pt)); and Group 11 of the periodic table (e.g., copper (Cu), silver (Ag), and gold (Au)). Metalloids (e.g., tellurium (Te), etc.) may also be used.

[0089] The activity of some of these metals as catalysts for ammonia decomposition has been reported by Masel et al (Catalyst Letters, vol. 96, Nos 3-4, July 2004) to change in the following order: Ru>Ni>Rh>Co>Ir>Fe>>Pt>Cr>Pd>Cu>>Te (Ru is a more active catalyst, while Te is a less active catalyst.)

[0090] The catalyst metal does not necessarily have to be supported, but is usually supported on a suitable support (e.g., metal oxide supports such as silica (SiO2), alumina (Al2O3), zirconia (ZrO2), or mixed metal oxide supports such as spinel (MgAl2O4) or perovskite (CaTiO3)). The activity of a supported metal catalyst may depend in part on the loading of the catalytically active metal on the support. In this regard, the metal loading may vary according to a pre-selected set of design criteria. In some implementations, the metal loading of the catalyst material may range from about 0.1% by weight to about 70% by weight. For example, with some catalyst materials, the loading may be closer to the lower end of the range (e.g., for more active metals, e.g., ruthenium, about 0.1% to about 10% or about 0.2% to about 5%), while for less active metals (e.g., nickel), the loading may be closer to the upper end of the range (e.g., about 20% to about 65%).

[0091] The supported metal catalyst that may be used may not be promoted, or it may be promoted with at least one other metal, for example, one or more Group 1 metals (e.g., lithium (Li), sodium (Na), and potassium (K)), Group 2 metals (e.g., magnesium (Mg) and calcium (Ca)), or Group 13 metals (e.g., aluminum (Al)) to improve the activity of the catalyst material.

[0092] Bimetallic catalysts, or catalysts containing two catalytically active metals, are also suitable for use in the present invention. Examples include composite metals, metal alloys, or metal nanoclusters supported on perovskites, composite oxides, or nitrides, or mixed oxides or mixed nitrides, as disclosed in U.S. Patent Application Publication No. 2021 / 0001311A (e.g., CoNi-MgSrCeO4 and 1 wt% K-CoNi-MgSrCeO4). Other types of multi-metal ammonia decomposition catalysts may also be used.

[0093] In embodiments of the apparatus and process, any number of suitable ammonia decomposition catalysts can be used as catalyst materials. Examples of suitable catalyst materials are disclosed in U.S. Patent Application Publication No. 2015 / 0217278A and in Lamb et al (Int. J. Hydrogen Energy, 44 (2019) pp3726-3736) and Boisen et al (J. Catalysis 230 (2005) pp309-312).

[0094] Prior to the operation of apparatus 1 for ammonia decomposition, the catalyst material in one or more tubes and / or one or more pre-reactors of furnace F201 (e.g., in embodiments where multiple pre-reactors can be used, the first and second pre-reactors C142 and C141) may be fully activated through a catalyst activation process. The catalyst material can be considered fully activated when it is sufficiently activated so that ammonia decomposition can be carried out efficiently in accordance with the pre-selected ammonia decomposition design temperature of apparatus 1 for ammonia decomposition. For example, the catalyst material may be fully activated when the entire oxide layer or passivation layer is removed from the catalyst material. As another example, the catalyst material may be fully activated when a substantial portion of the oxide layer or passivation layer is removed from the catalyst material (e.g., 55% to 100% of the oxides in the passivation layer and / or catalyst material are removed, or 75% to 100% of the oxides in the passivation layer and / or catalyst material are removed), so that the ammonia decomposition temperature required for ammonia decomposition can be considerably reduced within the pre-selected design parameters of apparatus 1 for ammonia decomposition. As yet another example, complete activation of the catalyst material can be achieved when the use of the catalyst to promote ammonia decomposition can be provided without any heat being generated through the catalyst material. As yet another example, complete activation of the catalyst material can be achieved when the use of the catalyst material to promote ammonia decomposition can be provided without using excessive temperatures for the ammonia decomposition reaction within the pre-selected temperature design limits of apparatus 1. As yet another example, complete activation of the catalyst material can be detected when the catalyst material is sufficiently activated to enable apparatus 1 for ammonia decomposition to decompose ammonia within the pre-selected design criteria of apparatus 1. As yet another example, the catalyst material can be fully activated when the use of the catalyst to promote ammonia decomposition can be provided without generating a significant level of heat from the catalyst. A fully activated catalyst material can be positioned so that the catalyst material is in a suitable state (e.g., through substantial removal of the passivation layer and / or substantial removal of oxides from the catalyst material, etc.) to promote ammonia decomposition within an acceptable rate that may be defined by the pre-selected design criteria of apparatus 1 for ammonia decomposition.Detection of complete activation of the catalytic material may be provided by monitoring a pre-selected set of criteria that may include pre-defined temperature profiles and / or pre-defined reactant concentration profiles during the catalytic activation process.

[0095] The catalyst activation process may be used at the start of the process (for example, after the installation of the ammonia decomposition equipment, or after the first cycle in which used catalyst material has been replaced with fresh catalyst material). The activation process used to activate the catalyst material may utilize the process elements of the ammonia decomposition unit 1 before the ammonia decomposition unit 1 is supplied with a larger ammonia feed to produce hydrogen through the ammonia decomposition operation.

[0096] For example, in the first catalyst activation phase, hydrogen (H2) can be supplied to the apparatus as the first reactant for supply to the pre-reactor and furnace F201 to help promote the activation of the catalyst material in the tubes within the radiation section 89 of furnace F201 and pre-reactors (e.g., pre-reactors C141 and C142). In some configurations, hydrogen H2 can be supplied to the conduit through which ammonia passes during the ammonia decomposition operation to preheat before being supplied to the pre-reactor and furnace F201. For example, hydrogen H2 can be supplied to the preheat exchanger feed conduit through which a stream of preheated liquid ammonia 6 passes to the heat exchanger E312 when the ammonia decomposition operation is to take place.

[0097] In some embodiments, hydrogen H2 can be fed as a mixture of hydrogen gas and nitrogen gas to provide a desired concentration of hydrogen as the first reactant gas during the first catalyst activation phase. Nitrogen can also be injected into this reactant gas as it passes toward the prereactor and furnace F201 via at least one nitrogen injection feed (N2). The hydrogen reactant flow can be preheated via flue gas output from the combustion of fuel flow 70, which may occur through the combustion chamber of furnace F201, by passing through a heat exchanger. The heat from the burned fuel can provide preheating to the first reactant and can also provide a heat source for heating the catalyst material during catalyst activation so that the catalyst temperature rises in a desired ordered manner, while the catalyst is simultaneously exposed to the reactant hydrogen gas for activation of the catalyst material.

[0098] For example, flue gas output from furnace F201 can be used as a heating medium to preheat a hydrogen reactant gas passing through one or more preheating heat exchangers (e.g., heat exchanger E2102 or other heat exchangers). In some embodiments, the hydrogen reactant gas may be injected so as to pass through only a subset of such heat exchangers, depending on how much preheating of the hydrogen reactant may be required to provide the desired heating of the catalyst material through the heated flow of reactant gas.

[0099] The preheated hydrogen reactant gas can then be fed to a first pre-reactor C141 to pass through the bed of catalyst material in the reactor vessel. The hydrogen reactant gas and products from catalytic activation reactions that may arise from oxides, oxide layers, or passivation layers of the catalyst material reacting with hydrogen in the reactant gas stream are discharged from the first pre-reactor C141 and heated in a heat exchanger E2103 to a desired second pre-reactor feed temperature for feeding the reactant stream to the second pre-reactor C142.

[0100] The preheated hydrogen reactant gas may then be fed through the catalyst material bed in the second prereactor C142, thereby allowing the products from the catalyst activation reaction, which may arise from the passive layer or oxides of the catalyst material reacting with the hydrogen reactant gas in the reactant gas stream, to be discharged from the second prereactor C142, heated in the heat exchanger E305, and subsequently heated to a desired furnace feed temperature for feeding the reactant stream into one or more tubes of the furnace F201 for activation of the catalyst material in the tubes of the radiation section 89 of the furnace F201.

[0101] The formation of a first reactant gas and catalyst activation product elements via a catalyst activation process in which a first reactant gas (e.g., hydrogen) reacts with oxides of catalyst materials that are not yet fully activated (e.g., oxides of the oxide layer, oxides of the passivation layer, etc.) may occur in the first catalyst activation phase so that the reactant gas is recirculated during the first catalyst activation phase. For example, the internal reactant gas and catalyst activation product elements may be output from the tubes of the radiating section 89 of furnace F201, while simultaneously undergoing heating via the combustion of fuel in the furnace to pass through heat exchangers E305, E310, E311, and / or E312 to preheat fresh and / or recycled reactant gas that is then fed toward the preheating reactor and furnace F201. The first reactant gas can then pass through a knockout drum located upstream of the hydrogen recovery unit U501 to help remove water from the reactant gas that may be present through the activation process, and then pass through a reactant recirculation conduit arrangement for recirculation through the heat exchangers, pre-reactors, and tubes of furnace F201. The reactant recirculation conduit arrangement may be configured such that the recirculated reactant passes through a first recirculation conduit segment HR1 located upstream of the hydrogen recovery unit U501, passing the first reactant gas through the compression system K681 where it is compressed and then output for recirculation, helping to account for any pressure drops that may arise from the reactant gas passing through different process elements. Nitrogen (N2) can also be supplied to the first reactant to increase the nitrogen concentration in the reactant gas and / or to provide a desired flow rate of the reactant gas. For example, nitrogen can be mixed with hydrogen in the first reactant to provide the first reactant at a pre-selected flow rate and / or to provide hydrogen at a pre-selected concentration within the first reactant to be used in the first catalyst activation phase.

[0102] A portion of the reactant gas can be exhausted through an exhaust flow (vent) so as to be necessary during the recirculation of the reactant gas to consider a desired hydrogen concentration or a desired temperature profile in the reactant gas, and / or the removal of undesirable components (e.g., reducing the water content in the reactant gas). The exhaust can allow for the removal of water that may accumulate in the reactant gas through the exhaust. Alternatively, fresh hydrogen gas H2 and / or nitrogen (N2) can be injected into the recirculated reactant gas during the first catalyst activation phase, and hydrogen and / or nitrogen can be replenished, taking into consideration that the hydrogen and / or nitrogen may react with the oxides, oxide layers, and / or passivation layers of the catalyst materials in furnace F201 and pre-reactors (e.g., pre-reactors C141 and C142) while those materials are not yet fully activated.

[0103] After the pressure of the reactant gas is increased by compression in the compression system K681, the recirculated output reactant gas can have a higher pressure and pass through the phase separator C6816. Moisture (e.g., water) can be removed as a liquid flow 56 through the phase separator, and the reactant gas can then be output as a flow 58 for feeding into a second reactant recirculation conduit segment HR2, which has an inlet located between the phase separator C6816 and the hydrogen recovery unit, and an outlet that fluidly communicates with a conduit through which the reactant gas can pass to be led to the heat exchanger, pre-reactor, and furnace F201. For example, the outlet of the second reactant recirculation conduit segment HR2 may be located upstream of one or more heat exchangers (e.g., upstream of heat exchangers E312, E311, and / or E310) where nitrogen (N2) can be injected, or upstream of a pre-reactor, and also upstream of furnace F201 to pass through one or more of the heat exchangers, pre-reactors, and tubes of furnace F201.

[0104] After a first level of catalyst activation is detected, the catalyst activation process may be adjusted to move to a second catalyst activation phase for completion of the catalyst activation process, and then to initiate the second catalyst activation phase. In some embodiments, the first level of catalyst activation may be pre-selected or pre-defined so that the catalyst material of the pre-reactor is fully activated during the first level of catalyst activation. Alternatively, the first level of catalyst activation may be pre-selected or pre-defined so that the catalyst material of the more active catalyst material in the tubes of furnace F201 is fully activated (e.g., the upstream layer of catalyst material in the tubes of furnace F201 in embodiments where the upstream layer contains a more active catalyst material (e.g., Ru-based catalyst material) and the downstream layer contains a less active catalyst material (e.g., Ni-based catalyst material)). The first level of catalyst activation may be pre-defined or pre-selected so that at least one layer of catalyst material in furnace F201 is not yet fully activated and requires additional activation to be fully activated.

[0105] In some embodiments, one or more sensors collect data (e.g., temperature data, hydrogen concentration data, etc.) to detect that a first level of catalytic activation has occurred, indicating that a first catalytic activation phase has been reached and that it is appropriate to proceed to a second catalytic activation phase. For example, it can be determined that a first level of catalytic activation has occurred by utilizing the detection of a first pre-selected temperature profile and / or hydrogen concentration present in the furnace F201, which may be provided via one or more sensors in the furnace F201 or apparatus 1. Such detection can be facilitated by a controller or control device communicably connected to one or more such sensors, which receives sensor data and provides the user with an output indicating that a pre-selected first level of catalytic activation has occurred.

[0106] Examples of a first level of catalyst activation that can be detected include the detection of a temperature of 150°C to 500°C in the outlet region or outlet of the radiation section 89 of furnace F201, a duration of exposure to the first reactant of hydrogen for 1 to 48 hours, and / or the detected hydrogen concentration at the outlet of the furnace tube having an upstream layer of catalyst material and a downstream layer of catalyst material of 10 mol% or more (e.g., 10 mol% to 30 mol%, 10 mol% to 20 mol%, 10 mol% to 25 mol%). A first level of catalyst activation can also be detected (or alternatively) based on monitoring of heat generation within the design constraints of apparatus 1. One or more exothermic conditions that can be monitored may include, for example, detecting a temperature rise greater than a pre-selected temperature rise over a pre-selected period during the first catalyst activation phase (e.g., a temperature rise of 5°C to 50°C over a pre-selected period during the first catalyst activation phase, a temperature rise of 15°C over a pre-selected period during the first catalyst activation phase, a temperature rise of 5°C to 15°C over a pre-selected period during the first catalyst activation phase, a temperature rise of 3°C to 12°C over a pre-selected period during the first catalyst activation phase, etc.).

[0107] Other embodiments may utilize other predetermined criteria to facilitate the detection of a first level of catalytic activation for use in triggering a transition from a first catalytic activation phase to a second catalytic activation phase, the transition of which may occur immediately after the completion of the first phase, such that the adjustment from the first catalytic activation phase to the second catalytic activation phase occurs immediately after the transition from the first catalytic activation phase to the second catalytic activation phase.

[0108] For example, in response to the detection of this first level of catalytic activation, a second catalytic activation phase can be initiated to continue the catalytic activation process. For example, such a transition to a catalytic activation phase may occur, for instance, after the temperature of the tubes in the radiation section 89 of furnace F201 reaches a temperature in the range of 300°C to 550°C and / or after the hydrogen concentration is detected to be in the range of 20 to 25 mol% or 15 to 25 mol%. As another example, the detection of the temperature of the flue gas output from the radiation section 89 of furnace F201, which is 400°C, 450°C, 500°C, or other temperatures in the range of 400°C to 500°C, can be used to detect the first level of catalytic activation and trigger a transition to a second catalytic activation phase. As another example, by detecting the temperature of the reactant gas (which may include water, etc., along with the reactant / catalyst material reaction products) emitted from the tubes of the radiation section 89 of furnace F201 at 400°C, 450°C, 500°C, or other temperatures in the range of 400°C to 500°C, a first level of catalytic activation can be detected, triggering a transition to a second catalytic activation phase.

[0109] As yet another example for detecting that a first level of catalytic activation is met, a pre-selected temperature threshold at a specific location (e.g., the outlet region of the furnace's radiation section 89) may be selected based on the temperature rating of an upstream heat exchanger of furnace F201 for preheating the ammonia feed supplied to the furnace F201 tubes for ammonia decomposition operation, and / or an SCR that may be available upstream of furnace F201 for preheating the ammonia feed that will be supplied to the furnace F201 tubes for ammonia decomposition. The temperature selected to facilitate detection of the first level of catalytic activation met to transition from the first catalytic activation phase to the second catalytic activation phase may be selected, for example, to avoid the temperature of the equipment being at the equipment's temperature rating, above the equipment's temperature rating, or within a pre-selected variance of the equipment's temperature rating (e.g., 15°C or 20°C lower than its temperature rating). Using such a temperature selection profile, it can be used to help prevent the equipment from being at or exceeding its designed temperature rating during a catalyst activation process, which may be used to fully activate all catalyst materials in the tubes of furnace F201 and the pre-reactor upstream of the furnace.

[0110] Of course (and as described above and elsewhere in this specification), a first level of catalytic activation obtained through a first catalytic activation phase can be predefined by using other first pre-selected catalytic activation temperature profiles and / or first pre-selected catalytic activation hydrogen concentrations. The selection of temperature profiles, reactant concentrations, and / or other parameters (e.g., exothermic parameters) that may be used may depend, for example, on the sizing of the tubes of furnace F201 having the catalytic material, the size and number of pre-reactors having the catalytic material, the type of catalytic material to be activated, and the temperature ratings of different instruments of apparatus 1.

[0111] The second catalyst activation phase may be initiated by stopping the feed of hydrogen (or other first reactant gas) to the pre-reactor and furnace F201 and starting the feed of ammonia as the second reactant to the pre-reactor and furnace catalyst material. For example, the feed of liquid ammonia 2 may be directed toward the preheating heat exchanger, pre-reactor, and furnace via a pump P101 which is started to feed ammonia as the second reactant. In some embodiments, nitrogen can be mixed with ammonia to dilute the ammonia concentration in the feed of ammonia passed through the pre-reactor and furnace F201 as the second reactant. For example, nitrogen can be mixed with ammonia to provide a desired flow rate to the second reactant as it passes through the catalyst material, including the tubes of the pre-reactor and furnace F201. For example, nitrogen can be mixed with the ammonia of the second reactant to provide the second reactant at a pre-selected flow rate and / or provide ammonia at a pre-selected concentration of the second reactant to be used in the second catalyst activation phase.

[0112] Furthermore, the further supply of hydrogen H2 as the first reactant can be stopped, and the hydrogen that was being supplied and / or recirculated via the reactant recirculation conduit arrangement can be stopped via exhaust of the hydrogen reactant with the catalyst activation reaction products contained therein, via at least one exhaust conduit to provide at least one exhaust flow (vent). The exhaust of the utilized and / or recirculated hydrogen reaction flow can be exhausted so that the reactant gas flow utilized during the initial first catalyst activation phase does not directly mix with the ammonia supplied to the apparatus via the supply of liquid ammonia 2 for the second catalyst activation phase. However, the exhaust of the hydrogen reactant gas can be done so that the hydrogen gas passes through heat exchangers E305, E310, E311, and E312 to preheat the ammonia. Flue gas from furnace F201 can also be used to preheat the ammonia via heat exchangers E2103 and E2012, and an oxidizer preheating heat exchanger E2142 for controlling the temperature of the ammonia reactant gas utilized during the second catalyst activation phase.

[0113] The feed rate of the ammonia provided as the feed of liquid ammonia as the second reactant for the second catalyst activation phase can be considerably lower than the feed rate of liquid ammonia 2 provided during the ammonia decomposition operation. For example, the feed rate of ammonia for the second catalyst activation phase may be 5% to 45%, or 20% to 40%, of the typical designed feed rate for the feed of liquid ammonia for the ammonia decomposition operation of apparatus 1. After the hydrogen reactant gas has been sufficiently exhausted, the ammonia used as the reactant for the second catalyst activation phase may be exhausted via an exhaust conduit (vent) upstream of the hydrogen recovery unit so that the ammonia used in the second catalyst activation phase is not recycled (for example, the ammonia passes through the pre-reactor and furnace F201 once and is used once throughout the process so that it is not recycled).

[0114] In other embodiments, it is intended that ammonia may instead be recirculated to further limit the amount of ammonia feed required for the second catalyst activation phase. In such embodiments, it is envisioned that ammonia recirculation may also be provided in a manner similar to that in which a first reactant gas containing hydrogen may be recirculated by utilizing a reactant recirculation conduit arrangement.

[0115] As can be understood from above, the supply of liquid ammonia 2 to the apparatus for the second catalyst activation phase can be passed through preheating heat exchangers E312, E311, E310, and E2102 to preheat to a desired temperature for later supply to the first prereactor C141. Fresh ammonia from a liquid ammonia source (e.g., a storage container or liquid ammonia storage unit) can be supplied for the continued operation of the second catalyst activation phase, so as to provide a heat sink that can help keep the various upstream preheating heat exchangers (e.g., heat exchangers E310, E311, E312, etc.) below a pre-selected temperature (e.g., to avoid overheating of the heat exchangers beyond the design temperature specification).

[0116] The preheated ammonia reactant can be preheated so that the ammonia vaporizes and becomes a gas before being fed to the first preheat reactor C141 via a preheating heat exchanger. The ammonia reactant gas can then be fed to the first pre-reactor C141 to pass through the bed of catalyst material in the reactor vessel. The ammonia reacts with the catalyst material inside and can be partially decomposed inside due to the complete activation of the catalyst material (for example, ammonia can be converted into some hydrogen and nitrogen as well as other components by reacting with the catalyst material in the first pre-reactor). The ammonia reactant gas and products from the resulting catalyst activation reaction can be discharged from the first pre-reactor C141 and heated in the heat exchanger E2103 to heat the ammonia reactant stream to a desired second pre-reactor feed temperature for later feeding the reactant stream to the second pre-reactor C142.

[0117] The preheated ammonia reactant gas may then be fed through the bed of catalyst material in the second prereactor C142, thereby releasing the ammonia reactant gas and products (e.g., hydrogen and nitrogen) from the reaction that may result from the interaction of ammonia with the catalyst material in the second prereactor C142 for the activation of the catalyst material in the tubes of the radiation section 89 of the furnace F201, and subsequently feeding the reactant stream into one or more tubes of the furnace F201. These products are then fed from the second prereactor C142 to the heat exchanger E305 to heat the ammonia reactant stream to the desired furnace feed temperature.

[0118] The formation of a second reactant gas and catalyst activation product elements (e.g., nitrogen and hydrogen) through a catalyst activation process in which a reactant gas (e.g., ammonia) interacts with the catalyst material may occur in the second catalyst activation phase, so that the reactant gas passes through the tubes of furnace F201. The ammonia and reaction products (e.g., nitrogen and hydrogen) can then be passed through the furnace tubes to help fully activate the less active catalyst material layers in the tubes that are not yet fully activated (e.g., the downstream layer when the downstream layer is a Ni-based catalyst material and the upstream layer is a Ru-based catalyst material). The ammonia reactant gas and product elements can then be discharged from the radiating section 89 of furnace F201, while the flue gas can also be discharged from the radiating section 89 to be fed into the conventional section 90 of furnace F201 to pass through different heat exchangers E2103, E2102, E2142, and / or E2112.

[0119] For example, the internal ammonia reactant gas and catalyst activation product elements may be discharged from the tubes of the radiating section 89 of furnace F201, while simultaneously undergoing heating via the combustion of fuel in the furnace, to subsequently pass through heat exchangers E305, E310, E311, and / or E312 to preheat the fresh ammonia reactant gas. The ammonia reactant gas may then be discharged upstream of the hydrogen recovery unit U501 after being discharged from heat exchanger E312.

[0120] Alternatively, in embodiments where ammonia can be recirculated, the ammonia reactant gas and activation products can be passed through a reactant recirculation conduit arrangement for returning and recirculating them through the heat exchanger, pre-reactor, and tubing of the furnace F201. In such embodiments where ammonia recirculation can be utilized, the reactant recirculation conduit arrangement may be configured to pass through a compression system K681 via a first reactant recirculation conduit segment HR1 that can pass through a feed conduit for a compression system K681 to undergo compression internally in order to be recirculated, passing through the first reactant from upstream of the hydrogen recovery unit U501 to help account for the pressure drop that may result from the reactant gas passing through different process elements. The reactant gas recirculation conduit HR2 may be positioned to facilitate routing of the compressed reactant gas output from the compression system K681 so that it can be recirculated back to the preheating heat exchanger, for example, in such an embodiment (for example, the compressed ammonia can be recirculated so that it passes through the phase separator C6816 and then, between the hydrogen recovery unit U501 and the phase separator, is redirected back towards the heat exchanger and / or pre-reactor via the second reactant recirculation conduit segment HR2).

[0121] The feed rate for the liquid ammonia 2 can be adjusted accordingly to account for the recirculation of the ammonia reactant gas (if ammonia recirculation is utilized). Also, if at least a portion of the ammonia is recycled instead of being exhausted in a single treatment scheme, the ammonia reactant gas can be periodically exhausted through at least one exhaust stream (vent) during the second catalyst activation phase to account for one or more parameters of a pre-selected control criterion.

[0122] Ammonia can pass through the tubes of the first pre-reactor C141, the second pre-reactor C142, and the radiation section 89 of furnace F201 during the second catalytic activation phase, providing sequential heating of the catalyst material in the tubes and providing complete catalytic activation of a pre-selected sequence. For example, heating of the catalyst material can be provided by passing heated ammonia gas, which can be heated by the combustion of fuel in furnace F201, thereby fully activating the least active catalyst material in the furnace tubes last. For example, if the downstream layer of catalyst material in the furnace tubes of furnace F201 is Ni-based and the upstream layer of catalyst material is Ru-based, the downstream Ni-based catalyst material can be fully activated last during the second catalytic activation phase via the use of ammonia reactant gas.

[0123] In some embodiments, heating of the catalyst material may be provided more directly by feeding a heated second reactant containing ammonia gas during the second catalyst activation phase and feeding a first reactant containing hydrogen used in the first catalyst activation phase, thereby fully activating the more active upstream layer of catalyst material in the tubes of furnace F201 first, the layer of catalyst material in the second pre-reactor C142 which is more active than the less active layer of catalyst material in the second pre-reactor C142, the catalyst material in the first pre-reactor C141 third, the less active layer of catalyst material in the second pre-reactor C142 fourth, and finally the less active downstream layer of catalyst material in the tubes of furnace F201 fully activated.

[0124] The heating of the catalyst material provided through the first and second reactants may be driven primarily by the heat of the flue gas of furnace F201, which heats the fluid in the furnace tubes within the radiating section 89 and may also be used as a heating medium in one or more preheating heat exchangers. Furthermore, the heating of the reactants passing through the tubes of furnace F201 may be further utilized to provide preheating of the reactants as the output reactant flow passes through heat exchangers E305, E310, E311, and E312, etc. The combustion of fuel in furnace F201 may be considered the primary source of heating provided through catalyst activation during the first and second catalyst activation phases.

[0125] Such feeding of the first and second reactants via the first and second catalyst activation phases may be carried out so that the more active layer of catalyst material in the tubes of furnace F201 is fully activated first, the more active layer of catalyst material in the second reactor C142, which is more active than the less active layer of catalyst material in the second reactor, is fully activated second, the catalyst material in the first reactor C141 is fully activated third, and the less active layer of catalyst material in the second reactor C142 is fully activated fourth in the first catalyst activation phase using the first reactor. The less active layer of catalyst material in the tubes of furnace F201 may then be fully activated last via the second reactant containing ammonia via the second catalyst activation phase. In embodiments where the less active layer of catalyst material in the tubes of furnace F201 is a downstream layer, this would result in the downstream layer of catalyst material in the tubes of furnace F201 being fully activated last.

[0126] In some embodiments, it is intended that there may be only one pre-reactor or three or more pre-reactors. In such embodiments, the first and second catalyst activation phases may be carried out so that the more active layer of catalyst material in the furnace tube F201 is activated first (e.g., the upstream layer if the upstream layer of catalyst material is a Ru-based catalyst and the downstream layer of catalyst material is a Ni-based catalyst). The pre-reactors can then activate the catalyst material in a sequential manner before the downstream layer of catalyst material, which is the less active layer of catalyst material in the furnace tube F201, is finally activated. If there is only one pre-reactor, the first and second catalyst activation phases may be carried out so that the more active catalyst material in the furnace tube is activated first, the catalyst material of the single pre-reactor is activated second, and then the less active layer of catalyst material in the furnace tube F201 can be activated last (e.g., the downstream layer of the furnace tube F201 can be fully activated last, if the Ni-based catalyst is the downstream layer and the Ru-based catalyst is the upstream layer in the furnace tube).

[0127] As another example, in an embodiment where there may be three pre-reactors, the first and second catalyst activation phases may be carried out such that the downstream pre-reactor in the pre-reactor group can activate its catalyst material first, then the pre-reactor downstream of the first pre-reactor can activate its catalyst material second, then the upstream pre-reactor can activate its catalyst material next, and then the downstream layer of catalyst material in the tubes of furnace F201 can be activated to complete the second catalyst activation phase.

[0128] The sequence of activation of different catalyst materials in the downstream and upstream layers of the catalyst material in the furnace tube, as well as the catalyst material in the pre-reactor, may be configured such that these elements reach different higher temperatures over a period of time at a desired activation rate set to promote the complete activation of the catalyst material without causing sintering of the catalyst material. The overall temperatures of each reactor and furnace, desired for the target sequenced catalyst activation, may depend on the type of catalyst material used. In some embodiments, the temperature profiles may be controlled so that the higher temperature points of different elements coincide with a desired sequence for catalyst activation. For example, the upstream portion of furnace F201 may first reach a desired final activation temperature for the complete activation of the upstream portion of the catalyst material in the tube of the radiation section 89 of furnace F201. Then, the temperature of the second pre-reactor C142 may reach a desired final activation temperature for the complete activation of the catalyst material in that pre-reactor. Then, the first pre-reactor C141 may reach a desired final activation temperature for the complete activation of the catalyst material in that pre-reactor. Finally, the temperature of the downstream portion of the tube in the radiation section having a second downstream layer of catalyst material can reach the desired final activation temperature of the downstream portion for the complete activation of the catalyst material. In such embodiments, the temperature of the downstream portion of the catalyst material in the furnace tube may be higher than the other activation temperatures (e.g., 500°C to 700°C, or 600°C to 650°C, etc.). The other activation temperatures may be approximately the same or vary between different desired temperatures (e.g., the temperature may vary between 300°C to 450°C, or 350°C to 500°C, etc.).

[0129] Figure 2 also shows an exemplary embodiment of a catalyst activation process that may include first and second catalyst activation phases. As can be seen from Figure 2, in the first step S1, hydrogen or other first reactant may be fed to activate the catalyst material in the upstream reactor (e.g., pre-reactors C141 and C142) and the furnace downstream of the reactor (e.g., furnace F201). Hydrogen may be fed during the first catalyst activation phase of the first step S1 until it is determined that the upstream section of the catalyst material in furnace F201 is under first pre-selected activation conditions (e.g., furnace F201 is determined to have conditions such as the furnace being at a first pre-selected temperature and / or a first pre-selected hydrogen concentration being detected in one or more tubes of the radiation section 89 of furnace F201). Complete activation of the catalyst material may include removal of coatings on the catalyst material (e.g., complete removal of oxides coating the entire outer surface of the catalyst material, complete removal of the passivation layer covering the entire outer surface of the catalyst material, etc.).

[0130] In the second step S2, ammonia can be supplied to the apparatus as a second reactant to be introduced into the furnace and upstream reactors (e.g., pre-reactor C141, pre-reactor C142, etc.) as a reactant to replace the first reactant (e.g., hydrogen) for the continued activation of the catalyst material in the furnace downstream of the reactor, so that the less active catalyst in the furnace can be fully activated.

[0131] In some embodiments, the feeding of a first reactant containing hydrogen in the first step S1 and the feeding of a second reactant containing ammonia in the second step S2 may be carried out so that the more active portion of the catalyst material in the furnace is first completely activated, the more active catalyst material in the second reactor of the upstream reactor (e.g., the second pre-reactor C142) downstream of the first reactor of the upstream reactor (e.g., the first pre-reactor C141) is second completely activated, the catalyst material in the first reactor of the upstream reactor is third completely activated, the less active catalyst material in the second pre-reactor is fourth activated, and the less active portion of the catalyst material in the furnace is last completely activated. Ammonia can be fed as pure ammonia or as ammonia diluted with nitrogen and used in the second step S2 to completely activate the less active portion of the catalyst material in the furnace. The first step S1 may be performed to fully activate other catalyst materials (for example, the more active portion of the catalyst material in the furnace is fully activated via the first step S1; the more active catalyst material in the second reactor of the upstream reactors located downstream of the first reactor of the upstream reactors (e.g., the second pre-reactor C142) is secondarily fully activated via the first step S1; the catalyst material in the first reactor of the upstream reactors is thirdarily fully activated via the first step S1; and the less active catalyst material in the second pre-reactor is fourtharily activated via the first step S1).

[0132] In yet another embodiment, the feeding of the first reactant containing hydrogen may be carried out so that catalyst material in one or more pre-reactors is initially generated in the first step, and a furnace having tubes with less active catalyst material is finally fully activated in the second step S2 via the feeding of a second reactant containing ammonia.

[0133] In other embodiments, a first reactant can be fed to fully activate the catalyst material in one or more pre-reactors, and, if present, the more active catalyst material in the furnace tubes. Then, a second reactant can be fed to the pre-reactors and furnace tubes to fully activate the less active catalyst in the furnace tubes, thereby completing the complete catalytic activation of the catalyst material. Then, a third step S3 can be performed for the ammonia decomposition operation.

[0134] As described above, in some embodiments, the feeding of ammonia may also include recirculating the ammonia reagent of the second reactant to the reactor and furnace, as well as other elements for catalyst activation (e.g., heat exchangers). The application of heat and feeding of ammonia may be provided during the second step S2 so that the complete activation of the catalyst material in the furnace and reactor may be carried out in a predefined sequence via the feeding of ammonia, which may help to avoid sintering of the catalyst material. Also, as described above, the first reactant containing hydrogen previously used in the initial first catalyst activation phase may be removed while the second reactant containing ammonia is utilized for the transition between the first and second catalyst activation phases (e.g., via the exhaust of the first reactant).

[0135] In the third step S3, after the downstream portion of the catalyst material in the furnace, which may have a less active catalyst material (for example, if the downstream portion of the catalyst material contains a Ni-based catalyst that is less active than the upstream portion of the catalyst material containing a Ru-based catalyst, then the downstream portion of the catalyst material in the tube of the radiation section 89 of furnace F201), has been fully activated, ammonia can be fed into the reactor and furnace to decompose ammonia and form at least one product stream of hydrogen for use downstream of the ammonia decomposition system (for example, transported to a remote customer via pipeline or vehicle and fed to a plant connected to the ammonia decomposition system for use of hydrogen). The feeding rate of ammonia provided during the third step S3 may be considerably higher than the feeding of ammonia performed during the second catalyst activation phase which may be performed during the second step S2. As discussed above, this process may result in the use of any exhaust cessation or reduction, non-use of the reactant circulation conduit configuration, and the optional use of the first portion 44 and / or second portion 46 of the off-gas flow 42 for use as a fuel source for the reactor, for use to further enhance hydrogen recovery via the hydrogen recovery unit U501.

[0136] We found that performing the second catalyst activation phase so that the less active downstream layers of the catalyst material in furnace F201 are activated last facilitates temperature control during the catalyst activation process, thus avoiding the prolonged use of excessive temperatures for catalyst activation of other upstream equipment, and thus avoiding exposure of various upstream equipment to excessively high temperatures. For example, the temperature profiles to which preheating heat exchangers E310, E311, E312, E2102, E2103, and E305 may be exposed can be minimized by such a catalyst activation sequence.

[0137] For example, we have found, surprisingly, that controlling the temperature profile in furnace F201 can drive the temperature of the catalyst activation process, at least in part, due to the recirculation of reactants during the catalyst activation process. In situations where catalyst materials with higher activation temperatures in the furnace are activated before other upstream equipment can be activated, the furnace temperature can become relatively high, which can result in the output reactant gas and flue gas flows becoming excessively hot when passing through other elements to the heat exchanger (e.g., recirculating the reactant gas to the pre-reactor). We have found that this can expose the heat exchanger to temperatures exceeding 600°C, well above the typical design rating of the heat exchanger equipment. This type of temperature condition during catalyst activation sequencing, where the reactant gas flow passing through the heat exchanger for preheating is relatively low, can result in the heat exchanger and conduits through which the flue gas and high-temperature reactant gas flows pass being exposed to much higher temperatures for a significant portion of the catalyst activation process. We also found that this type of temperature profile issue can be a key determinant of the placement of catalyst materials with very high activation temperatures in the tubes of furnace F201 compared to other catalyst materials used in the apparatus.

[0138] We have found that, surprisingly, controlling the catalyst activation by controlling the reactant temperature during stepwise catalyst activation, so that the less active layer of catalyst material in furnace F201 is activated last, can avoid exposing the heat exchanger to high-temperature flue gas and prolonged flow of reactants, thereby avoiding the problem of excessive high-temperature exposure. This can also provide a more standardized apparatus for the embodiment, which can offer greater design flexibility, maintenance flexibility, and reduced capital costs, as well as avoid production delays that may be associated with acquiring more specialized equipment.

[0139] The embodiment also allows catalytic activation to be performed without harmful sintering of the catalytic material while oxides and / or passivation layers are removed from the catalytic material for complete activation of the catalytic material. The first and second catalytic activation phases may be controlled so that the temperature during each phase gradually increases according to a predefined catalytic activation protocol. This temperature control may be achieved, for example, by passing an activating reactant (e.g., hydrogen mixed with nitrogen gas, ammonia, etc.) as described above.

[0140] We also found that using ammonia as a second reactant for the second catalyst activation phase can reduce the demand for other cooling media / equipment during catalyst activation (e.g., load saving for cooling water towers or air coolers), and can also provide a cooling source for the entire system (e.g., sensible heat, latent heat, endothermic reaction of ammonia decomposition forming nitrogen and hydrogen during the catalyst activation process). The ammonia that has passed through during the process of the second catalyst activation phase may be decomposed in the pre-reactor due to the heat required to produce hydrogen and nitrogen, which may be supplied to the upstream catalyst layer in the tubes of the radiating section 89 of reactor F201, where the ammonia can be further decomposed internally while being utilized as a reactant to provide more hydrogen for use in activating the downstream portion of the catalyst material in the tubes of the radiating section 89 of reactor F201. The ammonia feed rate during activation can be significantly lower than the design rate for ammonia decomposition, allowing a higher amount of conversion to occur via the pre-reactor than at the design point of ammonia decomposition (e.g., approximately 40-50% conversion vs. 20-30% conversion under the design conditions for ammonia decomposition). Since most of the ammonia used as the second reactant can be converted in the pre-reactor during the second catalyst activation phase, there is little to no endothermic heat from the ammonia decomposition reaction, allowing the temperature in the furnace tubes to rise rapidly to the desired activation temperature and consume the heat generated by the burner of furnace F201. This allows the activation process to proceed more quickly and also provides the desired temperature control in a stepwise manner for catalyst activation, while avoiding sintering of the catalyst material covered by the passivation layer.

[0141] After the catalyst material used in the ammonia decomposition unit 1 has been fully activated (for example, the passivation layer has been completely removed from the catalyst material), the ammonia reactant stream can be evacuated to remove impurities (e.g., water) from the activation process. The ammonia decomposition operation can then be initiated by feeding liquid ammonia at an ammonia decomposition feed rate for hydrogen production via ammonia decomposition (for example, as discussed above). For example, the ammonia decomposition operation can utilize the ammonia flow as discussed above to feed ammonia through the first pre-reactor, the second pre-reactor, and the tubes in the radiation section 89 of the reactor F201, decompose the ammonia to produce hydrogen, and then feed the decomposed gas to the hydrogen recovery unit U501 to form the hydrogen product stream 40.

[0142] It should be understood that the catalyst material that can be used in one or more prereactors and tubes of the radiation section 89 of furnace F201 can be any number of suitable catalyst materials for ammonia decomposition. The catalyst material can include supported and unsupported catalysts. The catalyst material can include catalysts containing Ni, Ru, and / or other suitable elements that may help promote the decomposition of ammonia to hydrogen and nitrogen. The shape of the catalyst material can also include any of a number of suitable shapes, including irregularly shaped catalyst particles, spherical catalyst particles, tubular catalyst particles, polygonal catalyst particles, or catalyst particles of other shapes. The bed of catalyst material having reactors and / or tubes in the radiation section 89 of furnace F201 can include, for example, an aggregate of particulate catalyst particles positioned so that ammonia can pass through the bed to come into contact with the catalyst particles or other types of catalyst material.

[0143] It should be understood that other modifications may also be made to satisfy a specific set of criteria for different embodiments of apparatus 1 or process. For example, the arrangement of valves, piping, and other conduit elements (e.g., conduit connection mechanisms, tubes, seals, valves, etc.) for interconnecting different units of the apparatus for fluid communication of fluid flow between different elements (e.g., pumps, compressors, fans, valves, conduits, etc.) may be arranged to satisfy a specific plant layout design, taking into account the available area of ​​the apparatus, the sized equipment of the apparatus, and other design considerations. For example, the size of each reactor, heat exchanger, and / or furnace, as well as the size and configuration of any adsorbent, adsorption system, heat exchanger, conduit, expander, pump, or compressor, may be modified to satisfy a specific set of design criteria. As another example, the flow rate, pressure, and temperature of fluid passing through one or more heat exchangers and / or reactors and / or at least one furnace, and through other plant elements, may vary, taking into account different plant design configurations and other design criteria. As yet another example, the number of plant units and how these plant units are arranged may be adjusted to satisfy a specific set of design criteria. As yet another example, the different structural components of a plant unit and the material compositions for the plant may be any type of suitable material that may be required to satisfy a particular set of design criteria.

[0144] As yet another example, in some embodiments, it is intended that only a single reactant containing ammonia (e.g., ammonia, ammonia mixed with nitrogen gas, etc.) may be used for catalyst activation. The ammonia used may be liquid ammonia that is vaporized, optionally mixed with nitrogen, and then passes through one or more pre-reactors and at least one tube having catalyst material located within the radiation section 89 of furnace F201 for the activation of the catalyst material. The activation of the catalyst material is carried out over a pre-selected period according to a pre-selected activation scheme, and can provide complete activation of all catalyst material within the temperature ratings of various instruments according to the pre-selected activation scheme. In some embodiments, such activation can be provided through the use of recirculation of at least a portion of ammonia, while adding additional liquid ammonia to the reactant feed to provide catalyst activation, and while controlling the temperatures of different pre-reactors / furnace tubes and heat exchangers to provide a sequence of catalyst activation, such that catalyst material having the highest activation temperature in the furnace tube is activated last, while other catalyst material is activated before catalyst material having the highest activation temperature in the furnace tube.

[0145] As yet another example, each embodiment of apparatus 1 and process may be configured to include process control elements arranged and configured to monitor and control their operation (e.g., temperature and pressure sensors, flow sensors, an automated process control system having at least one workstation, the at least one workstation comprising a processor, non-temporary memory, and at least one transceiver, the at least one transceiver for communicating with sensor elements, valves, and controllers, the controller for providing a user interface for the automated process control system which may run on the plant workstation and / or another computer device). It should be understood that embodiments may similarly utilize a distributed control system (DCS) for one or more process implementations and / or to control the operation of apparatus or process.

[0146] As another example, certain features, whether described individually or as part of an embodiment, are intended to be combined with other individually described features or parts of other embodiments. Thus, elements and operations of the various embodiments described herein can be combined to provide further embodiments. Therefore, while specific exemplary embodiments of processes, apparatus, systems, and methods for manufacturing and using them are shown and described above, it should be clearly understood that the present invention is not limited thereto and may be embodied in various other ways and implemented within the scope of the following claims. Examples of embodiments of the present invention are listed below. [Aspect 1] A process for activating a catalyst for ammonia decomposition, wherein the process is Feeding a first reactant containing hydrogen to at least one pre-reactor located upstream of a furnace, wherein the furnace has at least one tube within its radiating section, thereby allowing the first reactant to pass through the catalyst material of the at least one pre-reactor and then through the catalyst material of the at least one tube within the radiating section of the furnace. A process comprising, in response to detecting a first level of catalyst activation, stopping the feeding of the first reactant and starting to feed a second reactant, comprising ammonia, to the at least one prereactor and the at least one tube in the radiating section of the furnace, thereby starting the second reactant to pass through the catalyst material of the at least one prereactor and then through the at least one tube in the radiating section of the furnace to fully activate the catalyst material of the at least one tube. [Aspect 2] The process according to embodiment 1, wherein the feeding of the first reactant and the feeding of the second reactant are carried out such that the catalyst material in the upstream portion of the at least one tube is fully activated, then the catalyst material in the at least one pre-reactor is fully activated, then the catalyst material in the downstream portion of the at least one tube is fully activated after the catalyst material in the at least one pre-reactor is fully activated and after the catalyst material in the upstream portion of the at least one tube is fully activated. [Aspect 3] The process according to embodiment 1, wherein the feeding of the second reactant containing ammonia is carried out such that the catalyst material in the downstream portion of the at least one tube is finally fully activated. [Aspect 4] Mixing nitrogen with the ammonia in the second reactant such that the second reactant has ammonia at a pre-selected ammonia concentration and / or the second reactant has a pre-selected flow rate, and / or The process according to embodiment 1, comprising mixing nitrogen with the hydrogen of the first reactant such that the first reactant has hydrogen at a pre-selected hydrogen concentration and / or the first reactant has a pre-selected flow rate. [Aspect 5] The process according to embodiment 1, wherein the at least one prereactor includes a first prereactor having a catalyst material in the vessel of the first prereactor, and a second prereactor having a catalyst material in the vessel of the second prereactor, the second prereactor being downstream of the first prereactor such that the second prereactor is located between the at least one tube of the furnace and the first prereactor. [Aspect 6] The feeding of the first reactant is (a) The catalyst material in the upstream portion of at least one tube is fully activated, (b) The catalyst material of the second pre-reactor is fully activated, (c) The catalyst material in the first pre-reactor is activated so that it is fully activated. The feeding of the second reactant is (d) The process according to embodiment 5, wherein the catalyst material in the downstream portion of at least one tube is fully activated. [Aspect 7] The process according to embodiment 6, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than the catalyst material in the upstream portion of the at least one tube. [Aspect 8] The process according to embodiment 7, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than the catalyst material in the first pre-reactor. [Aspect 9] The process according to embodiment 8, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than at least a portion of the catalyst material in the second prereactor. [Aspect 10] The process according to embodiment 1, wherein the feeding of the first reactant further includes recirculating the first reactant through the at least one tube and the at least one pre-reactor over a first period of time. [Aspect 11] The process according to embodiment 1, comprising, in response to detecting a first level of catalyst activation, exhausting the first reactant and simultaneously beginning to feed the second reactant toward the at least one prereactor and the at least one tube. [Aspect 12] An apparatus for ammonia decomposition configured to facilitate catalyst activation, wherein the apparatus is, A furnace having at least one tube, wherein the furnace includes a catalytic material in the at least one tube for the decomposition of ammonia, and the catalytic material in the at least one tube has an upstream portion of the catalytic material and a downstream portion of the catalytic material, A pre-reactor located upstream of the at least one tube, wherein the at least one tube is in fluid communication with the at least one pre-reactor, comprising the at least one pre-reactor The aforementioned device The first reactant is feedable to the at least one prereactor and the at least one tube such that the first reactant passes through the catalyst material of the at least one prereactor and then through the catalyst material of the at least one tube, and Apparatus, sized and configured such that the first reactant can be exhausted in response to the second reactant detecting a first level of catalyst activation, and the second reactant can be fed into the at least one prereactor and the at least one tube so that the second reactant can pass through the catalyst material of the at least one tube to fully activate at least a portion of the catalyst material of the at least one tube, and then pass through the at least one tube. [Aspect 13] The apparatus is configured such that the feeding of the first reactant is carried out so that the upstream portion of the catalyst material in the at least one tube is first fully activated, and then the catalyst material in the at least one pre-reactor is fully activated. The apparatus according to embodiment 12, wherein the second reactant can be supplied to the at least one tube and the at least one pre-reactor so that the downstream portion of the catalyst material in the at least one tube is fully activated after the catalyst material in the at least one pre-reactor has been fully activated and the upstream portion of the catalyst material in the at least one tube has been fully activated. [Aspect 14] The apparatus according to embodiment 12, wherein the apparatus is configured such that the feeding of the second reactant is carried out so that the downstream portion of the catalyst material in the at least one tube is finally fully activated. [Aspect 15] The apparatus according to embodiment 12, wherein the at least one prereactor includes a first prereactor having a catalyst material in the vessel of the first prereactor, and a second prereactor having a catalyst material in the vessel of the second prereactor, the second prereactor being downstream of the first prereactor such that the second prereactor is located between the at least one tube of the furnace and the first prereactor. [Aspect 16] The apparatus, the feeding of the first reactant, (a) The upstream portion of the catalyst material in at least one tube is fully activated, (b) The catalyst material of the second pre-reactor is fully activated, (c) The catalyst material in the first pre-reactor is activated so that it is fully activated. The feeding of the second reactant is (d) The apparatus according to embodiment 15, wherein the catalyst material in the downstream portion of the catalyst material of at least one tube is configured to be fully activated. [Aspect 17] The apparatus according to embodiment 16, wherein the downstream portion of the catalyst material of the at least one tube has a higher activation temperature than the upstream portion of the catalyst material of the at least one tube. [Aspect 18] The downstream portion of the catalyst material in at least one tube has a higher activation temperature than the catalyst material in the first pre-reactor. The apparatus according to embodiment 17, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than at least a portion of the catalyst material in the second prereactor. [Aspect 19] The apparatus according to embodiment 12, further comprising a reactant recirculation conduit arrangement positioned such that the first reactant can be recirculated from the outlet of the at least one tube to the at least one pre-reactor. [Aspect 20] An apparatus for ammonia decomposition configured to facilitate catalyst activation, wherein the apparatus is, A furnace having at least one tube, wherein the furnace contains a catalytic material in the at least one tube for the decomposition of ammonia, and the catalytic material in the at least one tube has a more active portion of the catalytic material that is more active than the less active portion of the catalytic material, A pre-reactor located upstream of the at least one tube, wherein the at least one tube is in fluid communication with the at least one pre-reactor, comprising the at least one pre-reactor The aforementioned device The first reactant is feedable to the at least one prereactor and the at least one tube such that the first reactant passes through the catalyst material of the at least one prereactor and then through the catalyst material of the at least one tube, and Apparatus sized and configured such that the first reactant can be exhausted in response to the second reactant detecting a first level of catalyst activation, and the second reactant can be fed into the at least one prereactor and the at least one tube so that the second reactant can pass through the catalyst material of the at least one tube to fully activate the less active portion of the catalyst material of the at least one tube, and then pass through the at least one tube.

Claims

1. A process for activating a catalyst for ammonia decomposition, wherein the process is A first reactant containing hydrogen is fed to at least one pre-reactor located upstream of a furnace, wherein the furnace has at least one tube within its radiation section, thereby allowing the first reactant to pass through the catalyst material of the at least one pre-reactor and then through the catalyst material of the at least one tube within the radiation section of the furnace. A process comprising, in response to detecting a first level of catalyst activation, stopping the feeding of the first reactant and starting to feed a second reactant, comprising ammonia, to the at least one prereactor and the at least one tube in the radiating section of the furnace, thereby starting the second reactant to pass through the catalyst material of the at least one prereactor and then through the at least one tube in the radiating section of the furnace to fully activate the catalyst material of the at least one tube.

2. The process according to claim 1, wherein the feeding of the first reactant and the feeding of the second reactant are carried out such that the catalyst material in the upstream portion of the at least one tube is fully activated, then the catalyst material in the at least one pre-reactor is fully activated, then the catalyst material in the downstream portion of the at least one tube is fully activated after the catalyst material in the at least one pre-reactor is fully activated and after the catalyst material in the upstream portion of the at least one tube is fully activated.

3. The process according to claim 1, wherein the feeding of the second reactant containing ammonia is carried out such that the catalyst material in the downstream portion of at least one tube is finally fully activated.

4. Mixing nitrogen with the ammonia in the second reactant such that the second reactant has ammonia at a pre-selected ammonia concentration and / or the second reactant has a pre-selected flow rate, and / or The process according to claim 1, comprising mixing nitrogen with the hydrogen of the first reactant such that the first reactant has hydrogen at a pre-selected hydrogen concentration and / or the first reactant has a pre-selected flow rate.

5. The process according to claim 1, wherein the at least one prereactor includes a first prereactor having a catalyst material in the vessel of the first prereactor, and a second prereactor having a catalyst material in the vessel of the second prereactor, the second prereactor being downstream of the first prereactor such that the second prereactor is located between the at least one tube of the furnace and the first prereactor.

6. The feeding of the first reactant is (a) The catalyst material in the upstream portion of at least one tube is fully activated, (b) The catalyst material in the second pre-reactor is fully activated, (c) The catalyst material in the first pre-reactor is fully activated, The feeding of the second reactant is (d) The process according to claim 5, wherein the catalyst material in the downstream portion of at least one tube is fully activated.

7. The process according to claim 6, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than the catalyst material in the upstream portion of the at least one tube.

8. The process according to claim 7, wherein the catalyst material in the downstream portion of at least one tube has a higher activation temperature than the catalyst material in the first pre-reactor.

9. The process according to claim 8, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than at least a portion of the catalyst material in the second prereactor.

10. The process according to claim 1, wherein the feeding of the first reactant further includes recirculating the first reactant through the at least one tube and the at least one pre-reactor over a first period of time.

11. The process according to claim 1, comprising, in response to detecting a first level of catalyst activation, exhausting the first reactant and simultaneously beginning to feed the second reactant toward the at least one prereactor and the at least one tube.

12. An apparatus for ammonia decomposition configured to facilitate catalyst activation, wherein the apparatus is, At least one of a temperature sensor and a hydrogen concentration sensor, A furnace having at least one tube, wherein the furnace includes a catalytic material in the at least one tube for the decomposition of ammonia, and the catalytic material in the at least one tube has an upstream portion of the catalytic material and a downstream portion of the catalytic material, A pre-reactor located upstream of the at least one tube, wherein the at least one tube is in fluid communication with the at least one pre-reactor, comprising the at least one pre-reactor The aforementioned device A first reactant containing hydrogen is feedable to the at least one prereactor and the at least one tube such that the first reactant passes through the catalyst material of the at least one prereactor and then through the catalyst material of the at least one tube, and Apparatus sized and configured such that a second reactant containing ammonia can be fed to the at least one prereactor and the at least one tube, thereby allowing the first reactant to be exhausted in response to the detection of a first level of catalyst activation, and allowing the second reactant to be fed to the at least one prereactor and the at least one tube so as to be able to pass through the catalyst material of the at least one prereactor to completely activate at least a portion of the catalyst material of the at least one tube, and then pass through the at least one tube.

13. The apparatus is configured such that the feeding of the first reactant is carried out so that the upstream portion of the catalyst material in the at least one tube is first fully activated, and then the catalyst material in the at least one pre-reactor is fully activated. The apparatus according to claim 12, wherein the second reactant can be supplied to the at least one tube and the at least one pre-reactor so that the downstream portion of the catalyst material in the at least one tube is fully activated after the catalyst material in the at least one pre-reactor has been fully activated and the upstream portion of the catalyst material in the at least one tube has been fully activated.

14. The apparatus according to claim 12, wherein the apparatus is configured such that the feeding of the second reactant is carried out so that the downstream portion of the catalyst material in the at least one tube is finally fully activated.

15. The apparatus according to claim 12, wherein the at least one prereactor includes a first prereactor having a catalyst material in the vessel of the first prereactor, and a second prereactor having a catalyst material in the vessel of the second prereactor, the second prereactor being downstream of the first prereactor such that the second prereactor is located between the at least one tube of the furnace and the first prereactor.

16. The apparatus, the feeding of the first reactant, (a) The upstream portion of the catalyst material in at least one tube is fully activated, (b) The catalyst material in the second pre-reactor is fully activated, (c) The catalyst material in the first pre-reactor is fully activated, The feeding of the second reactant is (d) The apparatus according to claim 15, wherein the catalyst material in the downstream portion of the catalyst material of at least one tube is configured to be fully activated.

17. The apparatus according to claim 16, wherein the downstream portion of the catalyst material of the at least one tube has a higher activation temperature than the upstream portion of the catalyst material of the at least one tube.

18. The downstream portion of the catalyst material in at least one tube has a higher activation temperature than the catalyst material in the first pre-reactor. The apparatus according to claim 17, wherein the catalyst material in the downstream portion of the at least one tube has a higher activation temperature than at least a portion of the catalyst material in the second prereactor.

19. The apparatus according to claim 12, further comprising a reactant recirculation conduit arrangement positioned such that the first reactant can be recirculated from the outlet of the at least one tube to the at least one pre-reactor.

20. An apparatus for ammonia decomposition configured to facilitate catalyst activation, wherein the apparatus is, At least one of a temperature sensor and a hydrogen concentration sensor, A furnace having at least one tube, wherein the furnace contains a catalytic material in the at least one tube for the decomposition of ammonia, and the catalytic material in the at least one tube has a more active portion of the catalytic material that is more active than the less active portion of the catalytic material, A pre-reactor located upstream of the at least one tube, wherein the at least one tube is in fluid communication with the at least one pre-reactor, comprising the at least one pre-reactor The aforementioned device A first reactant containing hydrogen is feedable to the at least one prereactor and the at least one tube such that the first reactant passes through the catalyst material of the at least one prereactor and then through the catalyst material of the at least one tube, and Apparatus sized and configured such that a second reactant containing ammonia can be fed to the at least one prereactor and the at least one tube, thereby allowing the first reactant to be exhausted in response to the detection of a first level of catalyst activation, and allowing the second reactant to pass through the catalyst material of the at least one prereactor to completely activate the less active portion of the catalyst material in the at least one tube, and then pass through the at least one tube, so that the second reactant can be fed to the at least one prereactor and the at least one tube.

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