Ammonia dissociation process and system

Abstract

A process for dissociating ammonia into a hydrogen / nitrogen stream that dissociates within a catalytic tube in a radiant tube furnace and within a heat-insulated or isothermal unit containing a catalyst, and a downstream purification processing unit for purifying the dissociated hydrogen / nitrogen stream into a high-purity hydrogen product.

Description

Detailed Description of the Invention

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Application No. 63 / 353,402, filed on June 17, 2022, the entire content of which is incorporated herein by reference.

[0002] [Technical Field] The present invention relates to systems and methods for dissociating ammonia into nitrogen and hydrogen. By way of example, the systems and methods may be configured to dissociate ammonia into nitrogen and hydrogen within one or more reactors.

[0003] The world is moving towards the decarbonization of energy processes, i.e., towards clean energy. Ammonia is considered to be one of the most promising carbon - free long - distance energy carriers when considered as a hydrogen carrier. Storing and transporting gaseous hydrogen is costly. The high cost of hydrogen storage and transportation is mainly due to the expenses associated with the use of high - pressure tanks and pipelines for storing the gas.

[0004] There is an increasing opportunity and need to dissociate ammonia back into a mixture of hydrogen and nitrogen and use the hydrogen generated as a clean product or fuel. Thus, ammonia can be important as an energy carrier and for producing hydrogen. For example, ammonia can be used as a fuel carrier for power generation in areas with little or no fuel sources. Additionally, and instead, hydrogen can be transported by pipeline and supplied to various industries as a clean product and / or fuel. Further, ammonia can also serve as an energy source for leveling the variable power production from renewable energy technologies such as wind, solar, and hydroelectric power as an energy carrier. The advantage of ammonia as an energy carrier is that liquid ammonia is easier to transport and store compared to natural gas or hydrogen gas.

[0005] Green ammonia and blue ammonia can be produced in remote areas where the raw material cost is low or the raw materials are abundant. Green ammonia and blue ammonia are produced in remote areas where the raw material cost is low (e.g., natural gas in the case of blue ammonia) or the raw materials (e.g., wind power, sunlight, and hydropower in the case of green ammonia) are abundant. "Green ammonia" is defined herein as ammonia produced by a 100% renewable and carbon-free process. "Blue ammonia" is defined herein as ammonia produced by a low-carbon method such as natural gas stream reforming with carbon capture and underground storage.

[0006] In particular, it is desirable to find a productive method for dissociating ammonia (NH3) into relatively high-purity hydrogen (H2) and nitrogen (N2) so that hydrogen can be used as a clean product and / or fuel source.

[0007] [Summary of the Invention] This document describes examples of ammonia dissociation processes and systems that can substantially avoid one or more of the problems resulting from the limitations and drawbacks of the related art.

[0008] Additional features and advantages of the examples will be described in the following description, some will be apparent from the description, or can be learned by practicing the described processes and / or systems. The objectives and other advantages are realized and achieved by the processes and / or systems particularly shown in the specification and claims, as well as in the accompanying drawings.

[0009] As an example, a process for dissociating ammonia into hydrogen and nitrogen is provided, the process comprising preheating a liquid ammonia feedstock in a first preheater while recovering heat from a dissociated hydrogen / nitrogen stream to generate a preheated liquid ammonia stream; vaporizing the preheated liquid ammonia feedstock to generate a vaporized ammonia stream; dissociating at least a portion of the vaporized ammonia stream to generate a reactor effluent and a dissociated hydrogen / nitrogen stream by feeding the vaporized ammonia stream to a first reactor; feeding the reactor effluent to a radiant tube reactor provided in an ammonia dissociation furnace to generate a dissociated hydrogen / nitrogen stream; and feeding a low-carbon fuel to the ammonia dissociation furnace from tail gas from pressure swing adsorption, an unpurified mixed product from an ammonia scrubber, the vaporized ammonia stream, or a combination thereof.

[0010] As an example, dissociating the vaporized ammonia stream may include contacting the vaporized ammonia stream with one or more types of catalysts including a base metal catalyst, a noble metal-based catalyst, or a combination thereof. As an example, the base metal catalyst may include a nickel-based catalyst. As an example, the noble metal-based catalyst may include ruthenium.

[0011] As an example, feeding the vaporized ammonia stream to the first reactor may include feeding the vaporized ammonia stream to an adiabatic reactor or an isothermal unit.

[0012] As an example, feeding the vaporized ammonia stream to the first reactor may include feeding the vaporized ammonia stream to an isothermal unit configured to recover heat from the dissociated hydrogen / nitrogen stream.

[0013] As an example, the process may include recovering heat from the convection section of the ammonia dissociation furnace to heat a boiler feed water stream.

[0014] As an example, the process may include recovering heat from the convection section of the ammonia dissociation furnace to generate steam, and the steam may be directed to a steam drum. As an example, the steam may be used to heat an ammonia distillation unit downstream of the ammonia dissociation furnace or alternatively may be discharged from the unit. As an example, the process may include using steam to supply heat for vaporizing a preheated liquid ammonia feedstock.

[0015] As an example, the process may include recovering heat from the convection section of the ammonia dissociation furnace to heat an ammonia distillation unit downstream of the ammonia dissociation furnace.

[0016] As an example, the process may include preheating at least a portion of the fuel using one or more coils located within the convection section of the ammonia dissociation furnace.

[0017] As an example, the process may include supplying gas turbine exhaust to the ammonia dissociation furnace to supply combustion air to one or more burners of the ammonia dissociation furnace.

[0018] As an example, vaporizing a preheated liquid ammonia feedstock may include recovering heat from the dissociated hydrogen / nitrogen stream before the preheater recovers heat from the dissociated hydrogen / nitrogen stream.

[0019] As an example, the process may include supplying the dissociated hydrogen / nitrogen stream to a purification process after the preheater recovers heat from the dissociated hydrogen / nitrogen stream to produce a hydrogen product stream having a hydrogen concentration in the range of 75 mol% to about 99.99999 mol%.

[0020] As an example, a process for dissociating ammonia into hydrogen and nitrogen is disclosed, the process comprising supplying a vaporized ammonia stream to an adiabatic reactor comprising one or more types of catalysts for dissociating ammonia, and supplying the reactor effluent stream of the adiabatic reactor to one or more radiant tubes located within the radiant reactor section of an ammonia dissociation furnace to generate a dissociated hydrogen / nitrogen stream, the ammonia dissociation furnace comprising a convection section, supplying the reactor effluent stream of the adiabatic reactor to one or more radiant tubes located within the radiant reactor section of the ammonia dissociation furnace, and transferring heat from the convection section of the ammonia dissociation furnace to an ammonia distillation unit.

[0021] As an example, the process may include generating steam by recovering heat from the dissociated hydrogen / nitrogen stream.

[0022] As an example, the process comprises supplying the dissociated hydrogen / nitrogen stream to an ammonia scrubber configured to remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture and an aqueous ammonia solution, and supplying the aqueous ammonia solution to an ammonia distillation unit for recovery of unreacted ammonia and recovery of wash water.

[0023] As an example, a process for dissociating ammonia into hydrogen and nitrogen is disclosed, the process comprising dissociating ammonia from the vaporized ammonia stream under isothermal conditions while recovering heat from the dissociated hydrogen / nitrogen stream to produce a reactor effluent without a temperature change across the reactor, and supplying the reactor effluent to a radiant tube reactor to dissociate ammonia present in the reactor effluent and release a dissociated hydrogen / nitrogen stream.

[0024] As an example, a system for the dissociation of ammonia into hydrogen and nitrogen is disclosed, which may comprise an ammonia dissociation furnace that may include a convection section and a radiation section. The system may comprise a preheater heat exchanger arranged to receive a liquid ammonia feedstock and a dissociated hydrogen / nitrogen stream, the preheater heat exchanger being configured to transfer heat from the dissociated hydrogen / nitrogen stream to the liquid ammonia feedstock and generate a preheated ammonia stream. The system may comprise a vaporizer downstream of the preheater, the vaporizer being configured to vaporize the preheated ammonia stream to generate a vaporized ammonia stream. The system may comprise a first reactor configured to receive the vaporized ammonia stream, the first reactor comprising an adiabatic reactor or an isothermal unit. The system may comprise a radiant tube reactor located within the radiation section and downstream of the first reactor, configured to receive reactor effluent from the first reactor and discharge the dissociated hydrogen / nitrogen stream. The system may comprise a low-carbon fuel feedstock to the ammonia dissociation furnace from pressure swing adsorption, an ammonia scrubber, a vaporizer, or combinations thereof.

[0025] As an example, the first reactor may comprise an adiabatic reactor having an inlet condition temperature in the range of about 500 °C to about 750 °C and an outlet condition temperature in the range of about 300 to about 550 °C, or an isothermal unit having an inlet condition temperature in the range of about 300 °C to about 650 °C and an outlet condition temperature in the range of about 300 to about 600 °C.

[0026] The system may comprise a steam generation section configured to recover heat from the ammonia dissociation furnace, which may include one or more coils within the convection section of the ammonia dissociation furnace, and the heat in the steam may be utilized within the process.

[0027] As an example, a system for the dissociation of ammonia into hydrogen and nitrogen is disclosed, and the system may include an ammonia dissociation furnace that may include a convection section and a radiant reactor section. As an example, the system may include an ammonia distillation reboiler section located within the convection section of the ammonia dissociation furnace, which is thermally coupled to an ammonia distillation unit and is configured to recover heat from the convection section of the ammonia dissociation furnace and includes one or more coils. The system may include an adiabatic reactor that includes one or more types of catalysts for dissociating ammonia and reactor effluent. The system may include one or more radiant tubes located within the radiant reactor section of the ammonia dissociation furnace, configured to receive the reactor effluent from the adiabatic reactor and to discharge the dissociated hydrogen / nitrogen stream.

[0028] As an example, the system may include a heat exchanger that is functionally connected to a steam drum and is arranged to generate steam by recovering heat from the dissociated hydrogen / nitrogen stream.

[0029] As an example, the system may include a gas turbine exhaust feed to one or more burners located within the ammonia dissociation furnace.

[0030] As an example, the system may include an ammonia scrubber coupled to the ammonia distillation reboiler section, arranged to receive the dissociated hydrogen / nitrogen stream and configured to remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture and an aqueous ammonia solution. The aqueous ammonia solution is directed to the ammonia distillation unit for recovery of unreacted ammonia and recovery of wash water.

[0031] By way of example, a system for dissociation of ammonia into hydrogen and nitrogen is disclosed that may include an isothermal unit configured to receive a vaporized ammonia stream and to recover heat from the dissociated hydrogen / nitrogen stream, and a radiant tube reactor downstream of the isothermal unit and configured to receive a reactor effluent from the isothermal unit and to discharge the dissociated hydrogen / nitrogen stream.

[0032] By way of example, the isothermal unit may comprise a reactor / heat exchanger having an ammonia-containing inlet condition temperature in the range of about 300°C to about 650°C and an outlet condition temperature in the range of about 300 to about 600°C.

[0033] As an example, a radiant tube reactor may comprise one or more radiant tubes located within a radiant reactor section of an ammonia dissociation furnace that comprises a convection section.

[0034] By way of example, one or more of the above-described systems may include an ammonia scrubber for receiving the dissociated hydrogen / nitrogen stream and configured to remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture.

[0035] By way of example, one or more of the above-described systems may include a pressure swing adsorption unit configured to receive the hydrogen-nitrogen gas mixture from the ammonia scrubber and configured to purify the hydrogen-nitrogen gas mixture to provide a hydrogen product stream having a hydrogen concentration in the range of 75 mol% to 99.99999 mol%.

[0036] As an example, a pressure swing adsorption unit may have a flue gas exhaust that is directed to an ammonia dissociation furnace to be used as fuel.

[0037] As further illustrated in the examples set forth in the description below, any two or more of the process steps and / or system features described above may be combined.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0039] [Detailed Description] By way of example, the present disclosure describes a system and process for dissociating ammonia in one or more reactors. By way of example, the system and process may dissociate ammonia into hydrogen and nitrogen. By way of example, the system and process may produce a hydrogen product stream. By way of example, the system and process may produce a high-purity hydrogen product stream.

[0040] As an example, the hydrogen production stream may have various uses. For example, a high-purity hydrogen production stream may be used in a fuel cell. The fuel cell may be used as a generator. For example, the fuel cell may be used to supply power to a vehicle. For example, the fuel cell may be used in a power plant. For example, the hydrogen production stream may also be used in a pipeline. For example, the hydrogen production stream may be used in the steel and cement industries. For example, the hydrogen production stream may be used in an industrial plant. For example, the hydrogen production stream may be used as a clean combustion fuel in a power plant and / or other environments. Thus, the processes and systems described herein can serve to supply a hydrogen production stream for these and other uses.

[0041] As an example, dissociation may occur in one or more reactors. For example, the dissociation of ammonia may occur in the presence of one or more types of catalysts. For example, one or more types of catalysts may be provided in one or more reactors. For example, one or more reactors may comprise a first reactor and a second reactor. For example, the second reactor may be downstream of the first reactor.

[0042] As an example, the first reactor may comprise an adiabatic reactor or an isothermal unit. For example, the second reactor may comprise a radiant tube reactor. For example, the second reactor may comprise a down-fired furnace.

[0043] As an example, the second reactor may be the radiant section of an ammonia dissociation furnace. For example, one or more reactors may comprise an adiabatic reactor and a down-fired furnace, and / or a radiant tube reactor. For example, one or more reactors may comprise an isothermal unit and a down-fired furnace, and / or a radiant tube reactor.

[0044] As an example, the system and process may include the generation of steam for use as a heat source in part or multiple parts of the process and / or in other applications. As an example, steam may be generated by recovering heat from the convection section of an ammonia dissociation furnace. As an example, steam may be generated by recovering heat from the dissociated hydrogen / nitrogen stream produced by a second reactor, such as a radiant tube reactor.

[0045] As an example, the systems and processes herein provide heat recovery for preheating and / or vaporizing an ammonia feedstock. As an example, the energy or heat recovery may be from the dissociated hydrogen / nitrogen stream produced by a second reactor, such as a radiant tube reactor.

[0046] As an example, the system and process may optionally include a downstream purification system. As an example, the purification system may include one or more units for purifying the dissociated hydrogen / nitrogen stream into a high-purity hydrogen product stream. As an example, the purification system may be after cooling the dissociated hydrogen / nitrogen stream resulting from heat recovery for preheating and / or vaporizing the ammonia feedstock. As an example, the purification may include the use of an ammonia distillation unit. As an example, the described processes and systems may recover heat from an ammonia dissociation furnace and supply heat to an ammonia distillation unit.

[0047] As an example, the system or process can have zero direct carbon emissions and can generate and supply its own fuel for ammonia dissociation. As an example, the system or process may use, individually or in combination, any number of streams within the process as fuel. For example, clean fuel sources within the process may include vaporized ammonia, unpurified hydrogen-nitrogen mixtures downstream of an ammonia scrubber, off-gas or tail gas from a PSA, or combinations thereof. As an example, the system or process may not require the intake of natural gas for ammonia dissociation.

[0048] As an example, the system or process can generate and supply its own heat utilities required within the process, minimize integration with external units, and reduce costs associated with external support units. As an example, the heat required for the column reboiler of an ammonia distillation unit can be supplied by steam generated within the process or system from the heat available in the convection section of an ammonia dissociation furnace. As an example, the process or system can use steam as a medium to utilize the heat available within the system and transport the heat to where it is needed. As an example, the heat required for an ammonia distillation unit and / or its reboiler can be directly supplied from heat exchange using coils within the convection section of an ammonia dissociation furnace through which the coil gas from the ammonia distillation unit can pass, thereby directly using the heat available within the system.

[0049] Examples of the present invention shown in the accompanying drawings will be described in detail.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents, patent applications, published applications and publications, websites, and other published materials referenced throughout this specification are hereby incorporated by reference in their entirety, unless otherwise indicated. In the case of multiple definitions of terms in this specification, the definitions in this section shall prevail. It is understood that when a URL or other such identifier or address is referenced, such identifier may change and the information on the Internet may come and go, but equivalent information can be found by searching the Internet. By referring to these, it is proven that such information is available and generally widespread.

[0051] As used herein, the singular forms "a", "an", and "the" shall include the plural forms as well, unless the context clearly dictates otherwise.

[0052] The ranges and amounts used in this specification may be expressed as "about" a particular value or "about" a particular range. "About" includes the exact amount. Thus, "about 5 percent" means about 5 percent in addition to 5 percent. The term "about" means within the range of typical experimental error for the intended use or purpose.

[0053] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0054] As used herein, "combination" also refers to the relationship between two or more items. This relationship may be spatial or may refer to the use of two or more items for a common purpose.

[0055] Throughout the claims, the words "comprising" and "comprise" are to be interpreted as meaning "including but not limited to" and "include but not limited to", respectively.

[0056] As used herein, "any" or "optionally" means that the event or circumstance described thereafter may or may not occur, and the description includes both the case where the event or circumstance occurs and the case where it does not occur. For example, any component in a system means that the component may or may not be present in the system.

[0057] As used herein, the term "substantially" shall mean "mostly as specified, but not exactly as specified".

[0058] The terms used in this specification, such as first, second, third, etc., can be used to describe various elements, components, regions, layers, and / or parts. However, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or part from another region, layer, or part. The terms "first", "second", etc., and other numerical terms do not mean order or sequence unless clearly indicated by the context when used in this specification. Therefore, the first element, component, region, layer, or part described below can be referred to as the second element, component, region, layer, or part without departing from the teachings of the examples of the embodiments.

[0059] FIG. 1 illustrates an example of a system 10 for ammonia dissociation. By way of example, a liquid ammonia feedstock 12 may be supplied. By way of example, the liquid ammonia feedstock 12 may be supplied from a battery limit (e.g., an atmospheric storage tank). Other sources may also be used. By way of example, the liquid ammonia feedstock may contain a high concentration of ammonia. By way of example, the ammonia concentration in the liquid ammonia feedstock 12 can range from about 99.5 wt% to about 99.8 wt%. By way of example, the remainder of the liquid ammonia feedstock 12 may be water. By way of example, the liquid ammonia feedstock 12 may contain a composition comprising about 99.8 wt% ammonia and 0.2 wt% water.

[0060] As an example, the system may include a preheater 14 configured to preheat the liquid ammonia feedstock 12 to near its boiling temperature in stage (A). As an example, to form a preheated liquid ammonia stream 16, the liquid ammonia feedstock 12 may be preheated to from about 30° C. to about 100° C. As an example, the preheater 14 may be of any type of heater. As an example, the preheater 14 may include a process interchanger. As an example, preheating the liquid ammonia feedstock 12 in the first preheater 14 to produce a preheated liquid ammonia stream 16 may be performed while recovering heat from the dissociated hydrogen / nitrogen stream 20. As an example, preheating in stage (A) may be performed using residual heat from the dissociated hydrogen / nitrogen stream 20, which will be described in more detail later. As an example, the preheater 14 may be configured to recover heat from the dissociated hydrogen / nitrogen stream 20. As an example, the preheater 14 may be configured to transfer heat from the dissociated hydrogen / nitrogen stream 20 to the liquid ammonia feedstock 12 to produce a preheated liquid ammonia stream 16. As an example, the preheater 14 may be operated, and preheating in stage (A) may be performed, using residual heat from the dissociated hydrogen / nitrogen stream 20, which can improve the heat integration of the system and thus result in higher energy efficiency.

[0061] As an example, the system may include a vaporizer 18 downstream of the preheater 14. As an example, in step (B), the preheated liquid ammonia stream 16 from step (A) may be vaporized in the vaporizer 18 to produce a vaporized ammonia stream 24. As an example, the vaporizer 18 may be of any type. As an example, the vaporizer 18 may include heat transfer from the process. As an example, the vaporizer 18 may be configured to recover heat from the dissociated hydrogen / nitrogen stream 20. As an example, the vaporizer 18 may vaporize the preheated liquid ammonia stream 16 by transferring heat from the dissociated hydrogen / nitrogen stream 20 and / or cooling the dissociated hydrogen / nitrogen stream 20 and condensing the excess low-pressure steam. As an example, the low-pressure steam may be supplied by the discharge of the superheated steam section 62 in step (M), by the steam drum 64, by the discharge steam from the ammonia distillation unit 46, and / or from an external source as stream 22.

[0062] As an example, the system may include one or more heating means for further heating the vaporized ammonia stream 24 to produce a heated ammonia vapor stream 32. As an example, the vaporized ammonia stream 24 may be further heated. As an example, in step (C), the further heating of the vaporized ammonia stream 24 may be performed using the feedstock / discharge exchanger 26. As an example, the feedstock / discharge exchanger 26 may be configured to heat the vaporized ammonia stream 24 in the range of about 90°C to about 500°C. As an example, the feedstock / discharge exchanger 26 may include a heat exchanger. As an example, the feedstock / discharge exchanger 26 may be configured to recover heat from the dissociated hydrogen / nitrogen stream 20. As an example, the feedstock / discharge exchanger 26 may be configured to transfer heat from the dissociated hydrogen / nitrogen stream 20 to the vaporized ammonia stream 24.

[0063] As an example, the system may include an ammonia dissociation furnace 30. As an example, the ammonia dissociation furnace 30 may be configured to include a radiation section 40 for performing secondary ammonia dissociation by catalytic dissociation and a convection section 28.

[0064] As an example, in step (D), the vaporized ammonia stream 24 may be heated within the convection section 28 of the ammonia dissociation furnace 30.

[0065] As an example, the convection section 28 of the ammonia dissociation furnace 30 may comprise one or more optional components.

[0066] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally include a steam generation section 60 (also referred to as step L) at high pressure (up to about 120 bara), medium pressure (up to about 60 bara), or low pressure (e.g., up to about 10 bara). As an example, the steam generation section 60 may comprise one or more coils located within the convection section 28 of the ammonia dissociation furnace 30. As an example, the steam generation section 60 may be configured to recover heat from the convection section 28. As an example, the steam generation section 60 may be operably connected to a steam drum 64 and used to generate steam at a pressure in the range of about 3 bara to about 120 bara. As an example, by using the generated steam as a medium, it may be possible to utilize the heat available within the system and transport that heat to a desired location. As an example, the effluent from the steam generation section 60 and / or the effluent from the steam drum 64 may also be used to supply heat for the ammonia distillation unit 46, which may be part of a hydrogen purification process described in more detail later. As an example, the same steam may also be used to supply steam and / or heat to the vaporizer 18 to vaporize the preheated liquid ammonia stream 16. For example, after supplying heat to the ammonia distillation unit 46, the same steam may also be used to supply steam and / or heat to the vaporizer 18 to vaporize the preheated liquid ammonia stream 16.

[0067] As an example, the convection section 28 of the ammonia dissociation furnace 30 may include any superheated steam section 62 (also referred to as stage M). As an example, the superheated steam section 62 may be functionally connected to a steam drum 64. For clarity, in FIG. 1, the steam flow is indicated by a dotted line. As an example, the superheated steam section 62 may include one or more coils within the convection section of the ammonia dissociation furnace 30. As an example, the superheated steam section 62 may be configured to recover heat from the convection section 28. As an example, the superheated steam section 62 may be configured to superheat steam to 140°C to about 550°C. As an example, the superheated steam from the superheated steam section 62 may be used as a heat source for one or more other components. As an example, the effluent from the superheated steam section 62 may be used to supply heat for an ammonia distillation unit 46, which can be part of a hydrogen purification process described in more detail later. Further, as an example, after the ammonia distillation unit 46, the effluent from the superheated steam section 62 may be used to supply heat to vaporize the liquid ammonia stream 16 preheated in the vaporizer 18. As an example, by using steam as a medium, the heat available within the system can be utilized and transported to desired locations.

[0068] As an example, the process and system can generate and supply themselves with respect to heat utility requirements. As an example, the process and system can be made to generate and supply themselves with respect to heat utility requirements by using steam from the steam drum 64, steam from the effluent of the steam generation section 60, and / or superheated steam from the superheated steam section 62 as a heat transfer medium to one or more other components.

[0069] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally include a boiler feed water (BFW) preheating section 66 (also referred to as stage N). As an example, the BFW preheating section 66 may include one or more coils within the convection section 28 of the ammonia dissociation furnace 30. As an example, the BFW preheating section 66 may be configured to recover heat from the convection section 28. As an example, the BFW preheating section 66 may be configured to heat the BFW to a temperature in the range of about 130°C to about 350°C. As an example, the heated BFW may be supplied to the steam drum 64.

[0070] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally include a selective catalytic NOx reduction (SCR) section 68 (also referred to as stage O). As an example, the SCR section 68 injects an ammonia solution atomized by air into the NOx-containing flue gas generated by the ammonia dissociation furnace 30, and contacts and / or exposes the mixture to a catalyst bed configured to react ammonia with NOx, and may be configured to produce nitrogen gas and steam. In this way, it may be possible to reduce and / or eliminate the release of NOx into the atmosphere. As an example, the SCR section 68 may be configured to recover heat from the convection section 28. As an example, the ammonia solution injected into the SCR section 68 may be obtained from a part of the vaporized ammonia stream 24 and / or ammonia vapor 76, for example as shown in the figure.

[0071] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally include a combustion air preheating section 70 (also referred to as stage P). As an example, the combustion air preheating section 70 may include one or more coils for recovering heat to the combustion air preheating section 70. As an example, the combustion air 70 may be heated to a temperature in the range of about 100 to about 600°C. As an example, the heated combustion air may then be supplied to the radiant section 40 of the ammonia dissociation furnace 30 as an oxygen source for burning fuel.

[0072] As an example, the gas turbine exhaust 92 may optionally be incorporated into the system and process 10. As an example, the gas turbine exhaust 92 may contain a large amount of oxygen. Thus, as an example, the gas turbine exhaust 92 may also optionally be used as combustion air for use in the burner of the radiation section 40 of the ammonia dissociation furnace 30 to burn fuel. As an example, the gas turbine exhaust 92 may be supplied to the burner of the radiation section 40 separately from the heated combustion air from the combustion air preheating section 70 or as a mixed flow with the heated combustion air from the combustion air preheating section 70.

[0073] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally be provided with a fuel preheating section 84 (also referred to as stage Q). As an example, the fuel preheating section 84 may be used to preheat one or more types of fuel used in the radiation section 40 of the ammonia dissociation furnace 30. As an example, as shown in the figure, the fuel preheating section 84 may be used to preheat at least a part of the fuel from the exhaust gas or tail gas 54 and a part 74 of the hydrogen-nitrogen gas mixture 72 when mixed with the exhaust gas or tail gas 54. As an example, the fuel preheating section 84 may be provided with one or more coils for recovering heat in one or more types of fuel to be preheated. As an example, the fuel may be heated to a temperature in the range of about 100 to about 250 °C.

[0074] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally be provided with a water preheating section 86 (also referred to as stage R). As an example, the water preheating section 86 may be used to preheat water for an external heat source (heat utility) of the facility. As an example, the water preheating section 86 may be provided with one or more coils for recovering heat in the water to be preheated.

[0075] As an example, the convection section 28 of the ammonia dissociation furnace 30 may optionally include an ammonia distillation reboiler section 88 (also referred to as stage S). As an example, the ammonia distillation reboiler section 88 may be configured to supply heat to the ammonia distillation unit 46 by directly recovering heat from the convection section of the ammonia dissociation furnace, thereby enabling the process to be self-generated and supplied with respect to heat utility requirements. As an example, the ammonia distillation reboiler section 88 may include one or more coils for recovering heat used for regeneration in ammonia distillation (stage I) within the ammonia distillation unit 46. As an example, the gas from the ammonia distillation unit 46 may be circulated through one or more coils within the ammonia distillation reboiler section 88 of the convection section 28 of the ammonia dissociation furnace 30 using one or more illustrated pipes to recover heat from the convection section 28.

[0076] As an example, the convection section 28 of the ammonia dissociation furnace 30 may include one or more combinations of any of the above components. As an example, in addition to including at least stages (D) and (F) described herein, the convection section 28 of the ammonia dissociation furnace 30 may include one or more optional components. As an example, the convection section 28 of the ammonia dissociation furnace 30 may include a combination of all of the above components in addition to stages (D) and (F) illustrated in FIGS. 1-3, for example. As an example, although FIGS. 1-3 are shown as having everything present, any one or more combinations, or sub-combinations, of the optional components within the convection section 28 may be present in addition to stages (D) and (F) in any of the examples described with reference to FIGS. 1-3.

[0077] As an example, the convection section 28 of the ammonia dissociation furnace 30 may be configured to raise the temperature of the vaporized ammonia stream 24 by about 300°C to about 600°C. As an example, the vaporized ammonia stream 24 may be further heated first in the feedstock / effluent exchanger 26 in step (C) and then in the convection section 28 of the ammonia dissociation furnace 30 in step (D) to produce a heated ammonia vapor stream 32. As an example, the temperature of the heated ammonia vapor stream 32 may be in the range of about 500°C to about 750°C.

[0078] As an example, the system may comprise a first reactor. As an example, the system may comprise an adiabatic reactor 34 as the first reactor. As an example, in step (E), the system and method may comprise adiabatic primary dissociation. As an example, in step (E), the heated ammonia vapor stream 32 may be supplied to the adiabatic reactor 34. As an example, the adiabatic reactor 34 may comprise a reactor. As an example, the reactor may comprise a catalyst bed. As an example, the adiabatic reactor 34 for primary dissociation can be filled with one or more types of catalysts suitable for ammonia dissociation. As an example, in the adiabatic reactor 34, the heated ammonia vapor may be exposed to and / or contacted with one or more types of catalysts. As an example, the one or more types of catalysts can be base metals (e.g., Ni, Co, Fe), noble metals (e.g., Ru), or combinations thereof. As an example, the adiabatic reactor 34 may be filled with a nickel-based catalyst, a ruthenium-based catalyst, or a combination thereof, and / or a combination with other suitable catalysts. As an example, the nickel-based catalyst can enhance the activity. As an example, the ruthenium-based catalyst can improve the conversion rate and the equilibrium state to a relatively better extent.

[0079] As an example, the reactor 34 may be configured such that at least a portion of the ammonia in the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32 is dissociated into hydrogen and nitrogen according to reaction (Z). 2NH3 + heat ⇔ 3H2 + N2 (Z) Catalyst

[0080] As an example, not all of the ammonia from the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32 is dissociated within the adiabatic reactor 34. Thus, as an example, the first reactor effluent 36 may also contain hydrogen, nitrogen, water, unreacted ammonia vapor, or combinations thereof.

[0081] The dissociation reaction (Z) is an endothermic reaction. Thus, heat of decomposition is required for the reaction. As an example, the required heat of decomposition may be about 0.65 Gcal / MT, 12% ammonia energy. For the purposes of this description, assume that ΔH298 is 46 kJmol-1 NH3. Further, as an example, since the dissociation reaction is endothermic, the temperature of the first reactor effluent 36 of the adiabatic reactor 34 may be lower than the heated ammonia vapor stream 32 supplied to the adiabatic reactor 34.

[0082] As an example, the inlet conditions of the adiabatic reactor 34 may be from about 20 bara to about 50 bara, such as from 25 bara to about 40 bara. As an example, the inlet pressure may be an inlet pressure within any partial range of the stated inlet pressures. As an example, the inlet conditions of the adiabatic reactor 34 may be a temperature in the range of about 500 °C to about 750 °C, such as a temperature in the range of about 550 °C to about 675 °C. As an example, the inlet temperature may be an inlet temperature within any partial range of the stated inlet temperatures. As an example, the outlet temperature of the reactor 34 may be a temperature in the range of about 300 °C to about 550 °C, such as a temperature in the range of about 300 °C to about 500 °C. As an example, the outlet temperature may be an outlet temperature within any partial range of the stated outlet temperatures.

[0083] As an example, the process and system may include a secondary dissociation to convert at least a portion of the ammonia remaining in the first reactor effluent 36 that is ammonia from the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32. As an example, the secondary dissociation may include the use of a second reactor, as described below with respect to the radiant section 40 of the ammonia dissociation furnace 30, for example.

[0084] As an example, the process of this specification may include a step (F) of heating the first reactor effluent 36. As an example, the system may be configured to direct the first reactor effluent 36 into the convection section 28 of the ammonia dissociation furnace 30 to heat it before the first reactor effluent 36 reaches the radiation section 40, and may include one or more coils in the first reactor effluent heating section 38 of the convection section 28.

[0085] As an example, the first reactor effluent 36 may be heated in the first reactor effluent heating section 38 of the ammonia dissociation furnace 30 and then supplied to the second reactor in step (G). As an example, the second reactor may include the radiation section 40 of the ammonia dissociation furnace 30 for secondary dissociation treatment.

[0086] As an example, the radiation section 40 of the ammonia dissociation furnace 30 may include one or more tubes 80 filled with a catalyst. As an example, the tubes 80 filled with a catalyst may be arranged in one or more rows 82. As an example, as shown in the figure, the row 82 may be a vertical row. As an example, each row 82 may include one or more tubes 80. As an example, the arrangement may be in a harp shape (not shown).

[0087] As an example, in one or more tubes 80 filled with a catalyst, at least a part of the ammonia remaining in the first reactor effluent 36, which is ammonia from the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32, may be dissociated into hydrogen and nitrogen by a reaction mechanism similar to reaction (Z). As an example, the secondary dissociation treatment in the radiation section 40 may include "near-isothermal dissociation" in which heat is supplied using the combustion of one or more types of fuel, "heat input dissociation" in which heat is supplied using a heat flow, and / or "energy input dissociation" in which heat is supplied by the input of electrical energy.

[0088] As an example, the radiation unit 40 may be designed over a wide range. For example, the radiation unit 40 may include a radiation tube reactor, an electrochemical reactor, or a combination thereof. Other designs may also be implemented alone or in combination. For example, the radiation unit 40 may include one or more burners (not shown). For example, the heat for ammonia dissociation may be supplied by burning fuel. For example, the radiation unit 40 may include a downward combustion furnace, a side combustion furnace, a bottom combustion furnace, and / or a combination thereof. For example, in a downward combustion furnace, the direction of the flame is from the upper part to the lower part of the furnace.

[0089] As an example, the heat for the ammonia dissociation furnace 30 and / or the convection section 28 may be supplied from the radiation unit 40. For example, the heat for the ammonia dissociation furnace 30 and / or the convection section 28 may be supplied by fuel combustion, input of electrical energy, or a combination thereof.

[0090] As an example, the secondary dissociation tube 80 in the radiation unit 40 can be filled with one or more types of catalysts as described for the adiabatic reactor 34. For example, the same type of catalyst or different types of catalysts may be used in the radiation unit 40 and the adiabatic reactor 34. For example, the secondary dissociation tube 80 in the radiation unit 40 can be filled with a nickel-based and / or ruthenium-based catalyst. Other catalysts may also be used alone or in combination. For example, in the tube 80 and / or within the radiation unit 40, ammonia that may still be present in the first reactor effluent 36 may be exposed to and / or contacted with one or more types of catalysts.

[0091] As an example, the inlet pressure condition to the pipe 80 may be from about 20 bara to about 50 bara, for example, from about 25 bara to about 40 bara. As an example, the inlet pressure may be the inlet pressure within any partial range of the described inlet pressure. As an example, the inlet temperature of the radiant pipe 80 may be from about 450 °C to about 700 °C, for example, from about 525 °C to about 675 °C. As an example, the inlet temperature may be the inlet temperature within any partial range of the described inlet temperature. As an example, the outlet temperature of the pipe 80 may be in the range of about 500 °C to about 750 °C, for example, in the range of about 550 °C to about 700 °C. As an example, the outlet temperature may be the outlet temperature within any partial range of the described outlet temperature.

[0092] As an example, the discharge from the radiant section 40 is the dissociated hydrogen / nitrogen stream 20. As an example, the dissociated hydrogen / nitrogen stream 20 flowing out from the catalyst tube 80 of the radiant section 40 may contain hydrogen, nitrogen, water, and a few percent of unreacted ammonia vapor.

[0093] As an example, the heat from the dissociated hydrogen / nitrogen stream 20 from the radiant section 40 may be recovered. As an example, as described above, the dissociated hydrogen / nitrogen stream 20 may be cooled by one or more of the feedstock / discharge exchanger 26 (stage C), the vaporizer 18 (stage B), and the preheater 14 (stage A).

[0094] As an example, one or more of the purifications and / or treatments described with respect to stages H to K may optionally be performed on the dissociated hydrogen / nitrogen stream 20. As an example, one or more purification processes may be used to produce a high-purity hydrogen product stream. As an example, the dissociated hydrogen / nitrogen stream 20 may be cooled before entering the purification process. As an example, as shown in FIGS. 1 to 3, after the heat is recovered, the dissociated hydrogen / nitrogen stream 20 may be supplied to the purification process in order to preheat and / or vaporize the ammonia feedstock.

[0095] As an example, at stage H, the dissociated hydrogen / nitrogen stream 20 may be supplied to the ammonia scrubber 42. As an example, the dissociated hydrogen / nitrogen stream 20 may be supplied to the ammonia scrubber 42 after being cooled. As an example, the dissociated hydrogen / nitrogen stream 20 may be supplied to the ammonia scrubber 42 after the preheater 14 and / or the vaporizer 18 recover heat from the dissociated hydrogen / nitrogen stream 20. As an example, in the ammonia scrubber 42, most of the unreacted ammonia in the dissociated hydrogen / nitrogen stream 20 may be removed by the wash water 44. As an example, the ammonia scrubber 42 may include one or more types of emissions. As an example, the emissions from the ammonia scrubber 42 may include an aqueous ammonia solution 78. As an example, the effluent from the ammonia scrubber 42 may include a hydrogen-nitrogen gas mixture 72. As an example, the ammonia scrubber 42 may include the aqueous ammonia solution 78 of the first emission and the hydrogen-nitrogen gas mixture 72 of the second emission.

[0096] As an example, at stage I, the aqueous ammonia solution 78 from the ammonia scrubber 42 may be sent to the ammonia distillation unit 46. As an example, the ammonia distillation unit 46 may include a distillation column. As an example, for the heat to the ammonia distillation unit 46, as described above, steam and / or superheated steam from the steam drum 64, the steam generation section 60, and / or the superheated steam section 62 may be supplied. As described above, by using steam as a medium, it may be possible to utilize the heat available in the system and transport the heat to a desired location. As an example, the heat to the ammonia distillation unit 46 may be directly supplied from the ammonia distillation reboiler section 88 (also called stage S) by directly utilizing the heat available in the system. As an example, within the ammonia distillation unit 46, all of the unreacted ammonia 48 in the aqueous ammonia solution 78 may be separated from the wash water 44 and recycled to the inlet of the vaporizer 18 at stage B. As an example, the unreacted ammonia 48 may be mixed with the preheated liquid ammonia stream 16 before entering the vaporizer 18. The wash water 44 may be returned to the ammonia scrubber 42 at stage H.

[0097] As an example, the hydrogen-nitrogen gas mixture 72 flowing out from the ammonia scrubber 42 may contain hydrogen, nitrogen, water, and ammonia of less than 200 ppm. As an example, the hydrogen-nitrogen gas mixture 72 may have an ammonia concentration in the range of about 10 to about 200 ppm. As an example, in step J, the hydrogen-nitrogen gas mixture 72 may be sent to one or more pressure swing adsorption systems, unit 50. As an example, within the pressure swing adsorption unit 50, the hydrogen-nitrogen gas mixture 72 may be purified into a hydrogen product 52. As an example, the hydrogen product 52 may have a hydrogen concentration in the range of 75 mol% to about 99.99999 mol%. As an example, the hydrogen concentration of the hydrogen product 52 may be at least about 98 mol%. As an example, the hydrogen concentration of the hydrogen product 52 may be in the range of about 98 mol% to about 99.99999 mol%.

[0098] As an example, the exhaust gas or tail gas 54 may be sent to the ammonia dissociation furnace 30 as a by-product of the pressure swing adsorption unit 50. As an example, the exhaust gas or tail gas 54 may be a low-carbon fuel for the ammonia dissociation furnace 30 and the radiation section 40. As an example, the exhaust gas or tail gas 54 may be led to the radiation section 40 of the ammonia dissociation furnace 30. As an example, the exhaust gas or tail gas 54 may be used as a fuel for the radiation section 40 of the ammonia dissociation furnace 30.

[0099] As an example, the heat in the ammonia dissociation furnace 30 and in the radiation section 40 may be supplied by fuel and / or electricity. As an example, the heat is at least partially supplied by electricity. As an example, any fuel may be used to supply the heat.

[0100] As an example, the process or system described in this specification may show zero direct carbon emissions, and may even be able to generate and supply its own fuel for ammonia dissociation. As an example, the low-carbon fuel generated within the process or system may be used to supply power to the ammonia dissociation furnace 30 and the radiation section 40. As an example, the ammonia dissociation furnace 30 and the radiation section 40 may use the tail gas 54 from the pressure swing adsorption 50 as the main fuel, thereby making the process or system have zero direct carbon emissions and be able to generate and supply its own fuel for dissociation. As an example, the ammonia dissociation furnace 30 and the radiation section 40 may use at least a part 74 of the hydrogen-nitrogen gas mixture 72 from the ammonia scrubber 42 as a low-carbon fuel. As an example, a part 74 of the hydrogen-nitrogen gas mixture 72 may be used as the main fuel or to supplement the fuel, making the process or system have zero direct carbon emissions and be able to generate and supply its own fuel for dissociation. As an example, the ammonia dissociation furnace 30 and the radiation section 40 may optionally use a part of the ammonia vapor 76 from the vaporizer 18 and / or a part of the vaporized ammonia stream 24 as a low-carbon fuel, for example, the main fuel or to supplement the fuel, thereby making the process or system have zero direct carbon emissions and be able to generate and supply its own fuel for dissociation. As an example, a combination of two or more of the tail gas 54, the hydrogen-nitrogen gas mixture 72, and the ammonia vapor 76 may be used as the fuel for the ammonia dissociation furnace 30 and the radiation section 40. In this way, as an example, the process or system described in this specification may show zero direct carbon emissions and may even be able to generate and supply its own fuel for ammonia dissociation. In FIG. 1, a part 74 of the hydrogen-nitrogen gas mixture 72, the ammonia vapor 76 from the vaporizer 18, and / or a part of the vaporized ammonia stream 24 are shown by dashed lines.

[0101] As an example not shown, natural gas may be further incorporated into process or system 10 for use as fuel. As an example, since the system and process can generate and supply their own fuel for dissociation as described above, they may not require a natural gas feedstock and / or there may be no natural gas feedstock.

[0102] As an example, at stage K, to provide compressed hydrogen product 58, hydrogen product 52 may be compressed in compressor 56 to the pressure required at the battery limit.

[0103] The process and system 10 described herein with reference to FIG. 1 include at least one adiabatic reactor 34 as a first reactor and / or at least one radiant section 40 as a second reactor, but it will be understood that they do not necessarily include both. As an example, if both at least one first reactor or adiabatic reactor 34 and at least one second reactor or radiant section 40 are present, as schematically shown in FIG. 1, the first reactor, e.g., adiabatic reactor 34, is provided in sequence before the second reactor or radiant section 40 of ammonia dissociation furnace 30.

[0104] Figure 2 shows an example of system 10’. By way of example, system 10’ is similar to system 10 of FIG. 1 but has modifications to the steam generation system. In contrast to FIG. 1, FIG. 2 shows that the steam generation section 60 (stage L) has been removed. For ease of reference, modified elements and / or alternative elements are shown with a prime symbol (’). Other corresponding elements have the same reference numerals. By way of example, FIG. 2 shows a system in which BFW can be optionally preheated in coil N of BFW preheater 66 before being supplied to steam drum 64’. By way of example, steam may be further generated and / or heated by recovering heat from the dissociated hydrogen / nitrogen stream 20 using steam heat exchanger 94. By way of example, water and / or steam may be circulated through steam heat exchanger 94 to recover heat from the dissociated hydrogen / nitrogen stream 20 and then returned to steam drum 64’. By way of example, steam may optionally be generated from superheater 62 in stage M. By way of example, it may be possible to have both combinations of steam generation using superheater 62 and steam heat exchanger 94. By way of example, as described above, the steam may then be used to vaporize ammonia in vaporizer 18. By way of example, in this flow scheme, more heat may be available in convection section 28 to preheat the vaporized ammonia stream 24 to the heated ammonia vapor stream 32. By way of example, in this flow scheme, feedstock / discharge exchanger 26 may be omitted. By way of example, feed / discharge exchanger 26 may be replaced by steam heat exchanger 94.

[0105] As an example, the additional available heat may be used to supply heat to the ammonia distillation unit 46 in step (I). As an example, by providing an ammonia distillation reboiler section 88 (also referred to as step S), the additional available heat may be recovered within the convection section 28 of the ammonia dissociation furnace 30. As an example, the ammonia distillation reboiler section 88 may be configured to supply heat to the ammonia distillation unit 46 as described above. As an example, the ammonia distillation reboiler section 88 may include one or more coils to recover heat for use in the regeneration that takes place within the ammonia distillation unit 46 in ammonia distillation (step I) by circulating the gas from the ammonia distillation unit 46 through the one or more coils.

[0106] As an example, it may be possible to replace the adiabatic treatment with an isothermal treatment, whereby the ammonia dissociation reaction occurs with little or no temperature change since it is supported by heat input. As an example, ammonia from the vaporized ammonia stream may be dissociated under isothermal conditions while recovering heat from the dissociated hydrogen / nitrogen stream. FIG. 3 shows an example of the system 10”. As an example, the system 10” is similar to the system 10 of FIG. 1 and the system 10’ of FIG. 2 but has modifications regarding the first reactor. As an example, the modifications relate to the adiabatic reactor 34.

[0107] As described above, decomposing ammonia into hydrogen and nitrogen is an endothermic process based on equilibrium. As an example, reaction (Z) may be favored at high temperatures. As an example, as described above, the outlet temperature of the tubes 80 of the radiant section 40 of the ammonia dissociation furnace 30 may have a high temperature that can be in the range of about 500 °C to about 750 °C, for example in the range of about 550 °C to about 750 °C. As an example, this heat can be utilized for isothermal ammonia dissociation or decomposition reactions.

[0108] As an example, the isothermal ammonia dissociation or decomposition of ammonia contained in the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32 may be carried out in the isothermal unit 90 as the first reactor. As an example, the isothermal unit 90 may comprise a reactor-cum-heat exchanger. As an example, the reactor-cum-heat exchanger may comprise a catalyst bed having one or more types of catalysts for ammonia dissociation. As an example, within the isothermal unit 90, the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32 may be exposed to and / or contacted with one or more types of catalysts. As an example, one or more types of catalysts described above with respect to the adiabatic reactor 34 may be used within the isothermal unit 90.

[0109] As an example, not all of the ammonia from the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32 is dissociated within the isothermal unit 90. As an example, similar to the adiabatic reactor 34, the isothermal unit 90 is preferably provided in sequence in front of the second reactor, i.e., the radiation section 40, as schematically shown in FIG. 3. As an example, as shown in the drawing, the first reactor effluent 36' of the isothermal unit 90 may be supplied to the radiation section 40 for secondary dissociation. As an example, as described above, the first reactor effluent 36' may be heated within the first reactor effluent heating section 38 of the convection section 28. As an example, in order to convert at least a portion of the ammonia remaining in the first reactor effluent 36' with ammonia from the vaporized ammonia stream 24 and / or the heated ammonia vapor stream 32, the process and system may comprise the use of a second reactor, for example, as described herein with respect to the radiation section 40 of the ammonia dissociation furnace 30.

[0110] As an example, the inlet conditions of the isothermal unit 90 may be from about 20 bara to about 50 bara. As an example, the inlet pressure may be an inlet pressure within any partial range from 20 bara to 20 bara. As an example, the inlet conditions of the isothermal unit 90 may have a temperature in the range of about 300°C to about 600°C. The inlet temperature may be an inlet temperature within any partial range from 300°C to 600°C. As an example, the outlet temperature of the isothermal unit 90 may have a temperature in the range of about 300°C to about 600°C. As an example, the outlet temperature may be an outlet temperature within any partial range from 300°C to 600°C. As an example, the inlet temperature may be 300°C, and the outlet temperature may be 600°C. As an example, the inlet temperature may be 500°C, and the outlet temperature may be 500°C.

[0111] As an example, the temperature of the ammonia feedstock to the isothermal unit 90 can be kept substantially constant throughout the catalyst bed. This is because heat can be supplied constantly by the opposite side of the reactor exchanger. As an example, the heat may be supplied from the dissociated hydrogen / nitrogen stream 20 discharged from the radiation section 40 of the ammonia dissociation furnace 30.

[0112] As an example, by implementing the isothermal process, it may be possible to utilize the heat of ammonia decomposition and / or improve the process of simply utilizing the heat of ammonia decomposition. As an example, by implementing the described isothermal process, the utilization of high-quality heat (i.e., high-temperature and high-flux heat), such as the heat generated by the fuel from the ammonia dissociation furnace 30, etc., can be improved. As an example, the isothermal process can increase the conversion rate of ammonia to hydrogen compared to the adiabatic process described above. As an example, since the temperature is constant and high and does not decrease throughout the catalyst bed as in the adiabatic reactor, a higher conversion rate can be obtained for hydrogen production in the isothermal heat exchanger. As an example, the isothermal process may have a constant operating temperature, although lower than the adiabatic process. Therefore, the operating cost can be reduced, and the reliability of the device can be further improved.

[0113] As an example, the systems and processes described herein may provide one or more advantages. As an example, the systems and processes may provide a method for extracting hydrogen from ammonia. As an example, the systems and processes may provide a simplified and / or low-cost flowsheet design. As an example, the described systems and processes may provide high yields of products and high overall energy efficiency. As an example, the systems and methods may leverage proven process systems and apparatus designs. As an example, compared to existing technologies, which are often limited to relatively small scales (less than 5 metric tons per day), the systems and processes described herein can be scaled up (ammonia throughput exceeding 300 - 8500 metric tons per day). As an example, the described systems and processes can generate and supply their own energy with respect to the energy used for ammonia dissociation. As an example, the described systems and processes can operate on electricity and / or fuel. As an example, the described systems and processes can at least partially generate and supply their own energy with respect to the energy used for ammonia dissociation. As an example, compared to existing technologies, higher operating pressures and lower operating temperatures can be achieved. As an example, in the described processes and systems, more efficient utilization of high-quality heat can improve energy efficiency compared to existing technologies.

[0114] In the foregoing specification, the invention has been described with reference to examples, but the specification should be considered in an illustrative sense and not in a limiting sense. For example, apparatus, reactors, exchangers, furnaces, parts, process flows, processes, reactants, catalysts, products, and operating conditions that are within the scope of the claims or disclosed parameters but not specifically identified or tried in a particular instance are considered to be within the scope of the invention.

[0115] The present invention can be implemented even in the absence of elements that are not disclosed. In addition, the present invention may suitably comprise, consist essentially of, or consist of the disclosed elements. For example, a process for the dissociation of ammonia into hydrogen and nitrogen, the process comprising supplying ammonia vapor to the operating procedure of a reactor, consisting essentially of or consisting of this, and the operating procedure of the reactor being selected from the group consisting of adiabatic dissociation in a reactor equipped with a catalyst, dissociation in a radiant tube reactor equipped with a radiant tube equipped with a catalyst, and combinations of these two, and the process further comprising generating a hydrogen product stream, consisting essentially of or consisting of this, may be provided.

[0116] Furthermore, a system for the dissociation of ammonia into hydrogen and nitrogen, the system comprising a preheater for receiving liquid ammonia, configured to heat the liquid ammonia to provide a heated ammonia stream, a vaporizer for receiving the heated ammonia stream, configured to vaporize the ammonia, a feedstock / effluent exchanger for receiving the vaporized ammonia, configured to heat the vaporized ammonia, and a reactor for receiving the heated and vaporized ammonia, consisting essentially of or consisting of these, and the reactor being selected from the group consisting of an adiabatic dissociation reactor equipped with a catalyst, a dissociation reactor equipped with a radiant tube equipped with a catalyst, and combinations of these, and further the system comprising a hydrogen product stream withdrawn from the reactor, consisting essentially of or consisting of this, may be provided.

Claims

1. A process for dissociating ammonia into hydrogen and nitrogen, preheating a liquid ammonia feedstock in a first preheater while recovering heat from the dissociated hydrogen / nitrogen stream to produce a preheated liquid ammonia stream, vaporizing the preheated liquid ammonia feedstock to produce a vaporized ammonia stream, dissociating at least a portion of the vaporized ammonia stream to produce the dissociated hydrogen / nitrogen stream, feeding the vaporized ammonia stream to a first reactor to produce a reactor effluent, feeding the reactor effluent to a radiant tube reactor provided in an ammonia dissociation furnace, wherein dissociating at least a portion of the vaporized ammonia stream to produce the dissociated hydrogen / nitrogen stream, feeding a low-carbon fuel to the ammonia dissociation furnace from tail gas from pressure swing adsorption, an unpurified mixed product from an ammonia scrubber, the vaporized ammonia stream, or combinations thereof, comprising a process.

2. The process of claim 1, wherein dissociating the vaporized ammonia stream further comprises contacting the vaporized ammonia stream with one or more types of catalysts including a nickel-based catalyst, a ruthenium-based catalyst, or combinations thereof.

3. The process of claim 1, wherein feeding the vaporized ammonia stream to the first reactor further comprises feeding the vaporized ammonia stream to an adiabatic reactor or an isothermal unit.

4. The process of claim 1, wherein feeding the vaporized ammonia stream to the first reactor further comprises feeding the vaporized ammonia stream to an isothermal unit configured to recover heat from the dissociated hydrogen / nitrogen stream.

5. The process of claim 1, further comprising recovering heat from a convection section of the ammonia dissociation furnace to heat a boiler feed water stream.

6. The process of claim 8, further comprising generating steam by recovering heat from a convection section of the ammonia dissociation furnace.

7. The process of claim 6, further comprising using the steam to supply heat for vaporizing the preheated liquid ammonia feedstock.

8. The process of claim 1, further comprising recovering heat from the convection section of the ammonia dissociation furnace to heat an ammonia distillation unit downstream of the ammonia dissociation furnace.

9. The process of claim 1, further comprising supplying heat to the ammonia dissociation furnace by burning a fuel.

10. The process of claim 9, further comprising preheating at least a portion of the fuel using one or more coils located within the convection section of the ammonia dissociation furnace.

11. The process of claim 1, further comprising supplying gas turbine exhaust to the ammonia dissociation furnace to supply combustion air to one or more burners of the ammonia dissociation furnace.

12. Vaporizing the preheated liquid ammonia feedstock includes recovering heat from the dissociated hydrogen / nitrogen stream before the preheater recovers heat from the dissociated hydrogen / nitrogen stream, the process of claim 1.

13. The process of claim 1, further comprising supplying the dissociated hydrogen / nitrogen stream to a purification process after the preheater recovers heat from the dissociated hydrogen / nitrogen stream to produce a hydrogen product stream having a hydrogen concentration in the range of 75 mol% to about 99.99999 mol%.

14. A system for the dissociation of ammonia into hydrogen and nitrogen, An ammonia dissociation furnace comprising a convection section and a radiation section, A preheater heat exchanger arranged to receive a liquid ammonia feedstock and a dissociated hydrogen / nitrogen stream, the preheater heat exchanger configured to transfer heat from the dissociated hydrogen / nitrogen stream to the liquid ammonia feedstock to produce a preheated ammonia stream, A vaporizer downstream of the preheater, the vaporizer configured to vaporize the preheated ammonia stream to produce a vaporized ammonia stream, A first reactor configured to receive the vaporized ammonia stream, the first reactor comprising an adiabatic reactor or an isothermal unit, A radiant tube reactor located within the radiation section and downstream of the first reactor, configured to receive reactor effluent from the first reactor and discharge the dissociated hydrogen / nitrogen stream, A low-carbon fuel feedstock from pressure swing adsorption, an ammonia scrubber, the vaporizer, or a combination thereof to the ammonia dissociation furnace, A system comprising.

15. The first reactor is an adiabatic reactor having an inlet condition temperature in the range of about 500°C to about 750°C and an outlet condition temperature in the range of about 300 to about 550°C, or an isothermal unit having an inlet condition temperature in the range of about 300°C to about 600°C and an outlet condition temperature in the range of about 300 to about 600°C, The system of claim 14, comprising.

16. The first reactor includes one or more coils in the convection section of the ammonia dissociation furnace and is configured to recover heat from the ammonia dissociation furnace, and includes a steam generation section. The system of claim 14.

17. A system for dissociating ammonia into hydrogen and nitrogen, an ammonia dissociation furnace comprising a convection section and a radiation reactor section, an ammonia distillation reboiler section located in the convection section of the ammonia dissociation furnace, thermally coupled to an ammonia distillation unit, and configured to recover heat from the convection section of the ammonia dissociation furnace, the ammonia distillation reboiler section comprising one or more coils, an adiabatic reactor comprising one or more types of catalysts for dissociating ammonia and reactor effluent, one or more radiation tubes located in the radiation reactor section of the ammonia dissociation furnace, configured to receive the reactor effluent from the adiabatic reactor and discharge a dissociated hydrogen / nitrogen stream, The system comprising.

18. The system of claim 17, further comprising a heat exchanger operably connected to a steam drum and arranged to generate steam by recovering heat from the dissociated hydrogen / nitrogen stream.

19. The system of claim 17, further comprising a gas turbine exhaust feedstock to one or more burners located within the ammonia dissociation furnace.

20. An ammonia scrubber coupled to the ammonia distillation reboiler section, arranged to receive the dissociated hydrogen / nitrogen stream, and configured to remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture and an aqueous ammonia solution. The system of claim 17, wherein the aqueous ammonia solution is directed to the ammonia distillation unit for recovery of unreacted ammonia and recovery of the wash water.

21. A system for dissociating ammonia into hydrogen and nitrogen, An isothermal unit configured to receive the vaporized ammonia stream and recover heat from the dissociated hydrogen / nitrogen stream, A radiant tube reactor downstream of the isothermal unit, configured to receive reactor effluent from the isothermal unit and discharge the dissociated hydrogen / nitrogen stream, A system comprising the same.

22. The system of claim 21, wherein the isothermal unit comprises a reactor and heat exchanger having an inlet condition temperature in the range of about 300°C to about 600°C and an outlet condition temperature in the range of about 300 to about 600°C.

23. The system of claim 21, wherein the radiant tube reactor comprises one or more radiant tubes located within a radiant reactor section of an ammonia dissociation furnace having a convection section.

24. The system according to any one of claims 14, 17, or 21, further comprising an ammonia scrubber configured to receive the dissociated hydrogen / nitrogen stream and remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture.

25. The system of claim 24, further comprising a pressure swing adsorption unit configured to receive the hydrogen-nitrogen gas mixture from the ammonia scrubber and purify the hydrogen-nitrogen gas mixture to provide a hydrogen product stream having a hydrogen concentration in the range of 75 mol% to 99.99999 mol%.

26. The system of claim 25, wherein the pressure swing adsorption unit comprises flue gas emissions that are directed to the ammonia dissociation furnace and used as fuel.

27. A process for dissociating ammonia into hydrogen and nitrogen, Supplying a vaporized ammonia stream to an adiabatic reactor comprising one or more types of catalysts for dissociating ammonia, Supplying the reactor effluent stream of the adiabatic reactor to one or more radiant tubes located within a radiant reactor section of an ammonia dissociation furnace, the ammonia dissociation furnace having a convection section, to produce a dissociated hydrogen / nitrogen stream, Transferring heat from the convection section of the ammonia dissociation furnace to an ammonia distillation unit, Including the process.

28. The process of claim 27, further comprising generating steam by recovering heat from the dissociated hydrogen / nitrogen stream. **Claim 29** Supplying the dissociated hydrogen / nitrogen stream to an ammonia scrubber configured to remove unreacted ammonia from the dissociated hydrogen / nitrogen stream with wash water to produce a hydrogen-nitrogen gas mixture and an aqueous ammonia solution; Supplying the aqueous ammonia solution to the ammonia distillation unit for recovery of unreacted ammonia and recovery of the wash water; The process of claim 27, further comprising. **Claim 30** A process for dissociating ammonia into hydrogen and nitrogen, comprising: Dissociating ammonia from the vaporized ammonia stream under isothermal conditions while recovering heat from the dissociated hydrogen / nitrogen stream to produce a reactor effluent; Supplying the reactor effluent to a radiant tube reactor to dissociate ammonia present in the reactor effluent and release the dissociated hydrogen / nitrogen stream; A process comprising.

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