Methods and apparatus for ammonia synthesis

Abstract

Systems and methods for synthesis of ammonia are provided. Ammonia is synthesized using a bi-functional material in a chemical looping reactor, in two steps. The first step involves fixing nitrogen to the surface of the bi-functional material. In a second step, hydrogen is introduced to the surface of the material to react with the lattice nitrogen, generating ammonia. The order of these steps can be reversed. The system may include a control system in communication with the reactor to control operational parameter(s) associated with operation of the reactor for production of ammonia. The operational parameter(s) may include temperature, pressure, residence time, concentration and / or humidity. Ammonia may be supplied various downstream applications or processes, e.g., a fuel cell system; a refrigeration system, a selective catalytic reduction (SCR) system, a chemical feedstock production system, a system for production of synthetic fibers, a waste treatment system a water treatment system, and an agricultural applications.

Description

METHODS AND APPARATUS FOR AMMONIA SYNTHESISBACKGROUND OF THE INVENTION1. Cross-Reference to Related Application

[0001] The present application claims priority benefit to a U.S. provisional patent application entitled “Methods and Apparatus for Ammonia Synthesis’" which was filed on February 7, 2023, and assigned Serial No. 63 / 443,876. The entire content of the foregoing U.S. provisional patent application is incorporated herein by reference.2. Field of the Invention

[0002] The invention disclosed herein relates to production of ammonia and, in particular, to a low cost, two-step process for efficient synthesis of ammonia.2. Description of the Related Art

[0003] Ammonia (NH3) is a versatile chemical that has a variety of applications in different industries. Some of the most common uses of ammonia include: agriculture, refrigeration, cleaning, synthesis of chemicals, pharmaceutical and food processing, among others. For example, ammonia is used as a fertilizer in agriculture to provide nitrogen to crops, which is an essential nutrient for plant growth. Ammonia is used as a refrigerant in large-scale refrigeration systems due to its high thermal efficiency and low global warming potential. Ammonia is used as a cleaning agent, due to its ability to dissolve grease and grime. It is found in many household and industrial cleaning products. Ammonia is used as a starting material in the production of a variety of chemicals such as nitric acid, urea, and ammonium nitrate. Ammonia is used as a raw material in the synthesis of various pharmaceuticals, including antihistamines and tranquilizers. Ammonia is used as a sterilizing agent in the food industry to kill bacteria and preserve food products. These are just some of the many uses of ammonia, which highlights its importance as a versatile chemical in various industries. It is estimated that the global value of the ammonia industry is in excess of seventy billion dollars.

[0004] Ammonia is synthesized through the Haber-Bosch process, which involves the reaction of nitrogen gas (N2) and hydrogen gas (H2) to form ammonia (NH3). The reaction is performed under high temperature and pressure conditions, typically around 450°C and 200 atmospheres.A catalyst, usually iron or ruthenium, is added to the reaction mixture to increase the reaction rate and to ensure that the reaction goes to completion.

[0005] Ammonia has been industrially produced through the direct combination of N2 and H2 over an iron catalyst for over a century using the Haber-Bosch process shown in (Ri):N2+ 3H2<=> 2NHs (Ri)

[0006] The high temperature and pressure associated with the Haber-Bosch process (T = 450- 600°C, P = 10-25 MPa) are necessary to activate the stable triple bond of diatomic nitrogen and to push the equilibrium of Ri forward at an industrially favorable rate. However, these harsh conditions result in a low equilibrium concentration of ammonia due to the reverse reaction being thermodynamically favored at temperatures higher than 300°C. In practice, the unreacted reactants are recycled to the reactor feed at a high rate to achieve H2 conversions up to 27% in the Haber-Bosch process. Modem ammonia production plants use N2 from the atmosphere and H2 derived from steam reforming of methane in natural gas (SMR) to synthesize ammonia via Ri. Due to the high demand for ammonia, Haber-Bosch processes consume 2% of the global annual natural gas supply to generate H2 for the process. Ammonia production plants are often situated near large reserves of natural gas to satisfy demand, resulting in the large-scale centralization of the industry. The process itself consumes a significant amount of energy, estimated at 1-2% of global annual demand, primarily for the generation of hydrogen via steam methane reforming (SMR). In addition to its high energy requirements, the Haber-Bosch process also has a significant environmental impact, producing CO2 as a byproduct of SMR. The Haber-Bosch process is responsible for 1.6% of annual anthropogenic CO2 emissions worldwide, making it the most carbon-intensive chemical production process.

[0007] What are needed are more efficient methods and apparatus to produce ammonia than are presently available. Preferably, the techniques will result in a significant reduction in energy consumption and capital cost for producers and enable applications where cost was previously prohibitive. For example, the techniques should provide availability of ammonia for small-scale energy storage applications for renewable energy projects, onsite fertilizer production for farmers, and for onsite chemical manufacturing in the pharmaceutical industry.SUMMARY OF THE INVENTION

[0008] Systems and methods for synthesis of ammonia are disclosed. In an embodiment, ammonia is synthesized at atmospheric pressure using a bi-functional material in a chemical looping reactor, in two steps. The first step involves fixing nitrogen to the surface of the bifunctional material. In a second step, hydrogen is introduced to the surface of the material to react with the lattice nitrogen, generating ammonia. The order of these steps can be reversed.

[0009] In an embodiment, the two-step reactions may be controlled by switching the flow of gases in a fixed bed reactor, enabling independent control of the temperature in each step, thereby allowing the periodic synthesis of ammonia at low pressure.

[0010] In an embodiment, the bi-functional material, which functions as a N2 / H2 carrier, is an alloy of lanthanum-nickel (LaNis), which has been shown to synthesize ammonia at appreciable yields and at atmospheric pressure. The formation of nitride intermediates with a LaNis alloy may be performed in a nitrogen atmosphere. The subsequent hydrogenation of the NixNyor N polymers is thermodynamically favorable.

[0011] In an embodiment, a system for producing ammonia is provided, the system including (i) a reactor that includes an inlet, an outlet and a reactor region, and (ii) a bi-functional material within the reactor region, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas. The ammonia synthesis may occur at a temperature that is 300 degrees Celsius or less. The ammonia synthesis may occur at atmospheric pressure.

[0012] In an embodiment, the bi-functional material may be LaNi5, LaNi4.8Sn0.2, NiBaH2, Ni4W, TiMox [x = 1-3], ZrMnx [x = 1-3], Ni3Ga, MnNi3, Ni3Ge, Ce2MnN3, ZrCr, ZrCr2, Ni2Mo3N, LaCoSi, LaRuSi, Cs-Ru / MgO, Co2Mo3N, or a combination thereof.

[0013] In an embodiment, an ammonia synthesis promoter may be provided within the reactor region. The ammonia synthesis promoter may be sodium (Na), calcium (Ca), potassium (K), barium (Ba), ruthenium (Ru), or a combination thereof.

[0014] In an embodiment, a support material may be provided within the reactor region. The support material may be aluminum, lanthanum, magnesium, cerium oxide, or a combination thereof.

[0015] The system may include a control system. The control system may be in communication with the reactor. In an embodiment, the control system may include machine- readable instructions for controlling operational parameter(s) associated with operation of the reactor for production of ammonia. The operational parameter(s) may include temperature, pressure, residence time, concentration, humidity and combinations thereof.|0016| In an embodiment, a computer program product may be stored on non-transitory machine -readable media. The computer program product may include machine-readable instructions for (i) controlling production of ammonia by operation of a reactor that includes an inlet, an outlet and a reactor region, and (ii) a bi-functional material within the reactor region, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas.

[0017] In an embodiment, the computer program product may control production of ammonia by communicating over a network that includes a controller with computing capabilities, one or more sensors, a power supply, one or more motor operated valves, one or more switches, an interface and combinations thereof.

[0018] In an embodiment, control by the computer program product includes instructions for switching between gas supplies. In an embodiment, control by the computer program product includes instructions for monitoring the production of ammonia. In an embodiment, control by the computer program product includes instructions for operating a separator to recycle at least a portion of unreacted nitrogenous gas and unreacted hydrogenous gas. In an embodiment, control by the computer program product includes instructions for maintaining temperature of the reactor below a temperature for at least one of nitridation and decomposition of the ammonia.

[0019] In an embodiment, a system for producing ammonia includes (i) a reactor that includes an inlet, an outlet and a reactor region, (ii) a bi-functional material within the reactor region, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas, and (iii) a computer program product stored on non-transitory machine-readable media, the computer program product including machine-readable instructions for controlling the producing by managing operation of the reactor.

[0020] In an embodiment, the ammonia produced by the ammonia synthesis may be used in a downstream application, e.g., a fuel cell system, a refrigeration system, a selective catalytic reduction (SCR) system, a chemical feedstock production system, a system for production of synthetic fibers, a waste treatment system, a water treatment system, or an agricultural application.100211 In an embodiment, the system for ammonia synthesis may be configured as one of a fixed, mobile, temporary or permanent installation.

[0022] In an embodiment, a method for producing ammonia includes (i) introducing a bifunctional material into a reactor, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas, (ii) introducing nitrogen to the reactor, whereby nitrogen is fixed relative to the bi-functional material, (iii) discontinuing introduction of nitrogen to the reactor; and (iv) introducing hydrogen to the reactor, whereby ammonia is produced through reaction of the hydrogen with the nitrogen.

[0023] In an embodiment, the order of hydrogen introduction and nitrogen introduction is reversed.

[0024] In an embodiment, the reactor operates at a first temperature when the nitrogen is introduced to the reactor and the reactor operates at a second temperature when the hydrogen is introduced to the reactor. In an embodiment, the first temperature is the same as the second temperature. In an embodiment, the first temperature is greater than the second temperature.

[0025] In an embodiment, the first temperature may be between 200°C and 900°C. In an embodiment, the second temperature is between 100°C and 400°C. In an embodiment, the nitrogen production is performed under isobaric conditions.

[0026] In an embodiment, a control system is in communication with the reactor that controls one or more operational parameters associated with operation of the reactor for production of ammonia. The one or more operational parameters may include temperature, pressure, residence time, concentration and humidity. The ammonia produced by the ammonia synthesis may be used in a fuel cell system, a refrigeration system, a selective catalytic reduction (SCR) system, a chemical feedstock production system, a system for production of synthetic fibers, awaste treatment system, a water treatment system, an agricultural application or other downstream application(s).

[0027] Additional features, functions and benefits of the disclosed systems and methods will be apparent from the description which follows, particularly when read in conjunction with the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The features and advantages of the invention are apparent from the following description taken in conjunction with the accompanying drawings in which:

[0029] FIG. 1A is a schematic diagram depicting a reactor system;

[0030] FIGS. IB and 1C are schematic diagrams of the reactor system of FIG. 1A operating for nitrogen fixing (FIG. IB) and ammonia production (FIG. 1C) as part of a chemical loop synthesis;

[0031] FIG. 2 is an x-ray diffraction (XRD) profile;

[0032] FIGS. 3A and 3B are images of LaNis alloy particles (FIG. 3A) and pore (FIG. 3B) captured with a scanning electron microscope (SEM);

[0033] FIGS. 4A and 4B depict scan area of an LaNis alloy (FIG. 4A), and an energy-dispersive x-ray (EDX) profile and elemental analysis of LaNis alloy (FIG. 4B);

[0034] FIG. 5 depicts a schematic system for ammonia production and associated thermogravimetric analysis;

[0035] FIG. 6 is a graph depicting temperature and weight change of a LaNis sample in an atmosphere of nitrogen during synthesis;

[0036] FIGS. 7A and 7B depict XRD profiles of the LaNis alloy before (FIG. 7A) and after (FIG. 7B) synthesis;

[0037] FIGS. 8A and 8B are SEM images of the LaNis alloy surface before (FIG. 8A) and after (FIG. 8B) synthesis;

[0038] FIGS. 9A and 9B depict scan area an LaNis alloy (FIG. 9A), and EDX profile and elemental analysis of the LaNis alloy after synthesis in an atmosphere of nitrogen (FIG. 9B);

[0039] FIG. 10A depicts a schematic system for ammonia production and associated thermogravimetric analysis;

[0040] FIG. 10B depicts an experimental system constructed according to the schematic system depicted in FIG. 10 A.

[0041] FIGS. HA and 11B are graphs depicting operating conditions of a reactor during a reduction step with hydrogen gas introduction (FIG. 11 A) and the operating conditions of the reactor during chemical looping where nitrogen, hydrogen, and argon were cycled at a constant temperature of 270°C (FIG. 11B);

[0042] FIG. 12 is a graphic depicting composition at the reactor outlet during isothermal operation of a chemical loop ammonia synthesis;

[0043] FIG. 13 is a graph showing operating conditions of a reactor during high temperature operation of a chemical loop ammonia synthesis;

[0044] FIG. 14 is a graph depicting composition at the reactor outlet during high temperature operation of a chemical loop ammonia synthesis;

[0045] FIG. 15 is a flowchart showing a control system associated with ammonia synthesis;

[0046] FIG. 16 is a block diagram of a system for ammonia synthesis control;

[0047] FIG. 17 is a block diagram of a computing device for implementing the control system for ammonia synthesis; and

[0048] FIG. 18 is a block diagram of a system for an ammonia synthesis detection environment.DETAILED DESCRIPTION OF THE INVENTION

[0049] Disclosed herein are methods and apparatus for producing ammonia. Generally, the disclosed methods and apparatus provide for producing ammonia at atmospheric pressure using a bi-functional substrate material in a chemical looping reactor. Using techniques disclosed herein, ammonia may be synthesized in two steps. A first step involves fixing nitrogen to thesurface of the material. In a second step, hydrogen is introduced to the surface of the material to react with the lattice nitrogen, generating ammonia. The order of these steps can be reversed and additional embodiments may be practiced. In practice, the reactions may be controlled by switching the flow of gases into the reactor and independently controlling the temperature in the reactor, allowing for the synthesis of ammonia at low pressures.100501 Although embodiments disclosed herein are with regard to an alloy of lanthanum-nickel (specifically, LaNis), other materials may be suited for use in the ammonia synthesis processes disclosed. Additional examples of bi-functional materials that may be employed to synthesize ammonia by a chemical looping process include: NiBaH2. NuW, TiMox[x = 1-3], ZrMnx[x = 1-3], Ni3Ga, MnNi3, Ni3Ge, Ce2MnN3, ZrCr, ZrCr2, Ni2Mo3N, LaCoSi, LaRuSi, Cs-Ru / MgO, CO2MO3N as well as various combinations of the foregoing. These materials thermodynamically favor NH3synthesis through a chemical loop process.

[0051] The bi-functional material may be configured to effectively promote ammonia synthesis. For example, the bi-functional material may be pre-processed and / or introduced to the reactor such that the surface area of the bi-functional material available for nitridation and hydrogenation is maintained and / or maximized, e.g., through effective dispersion of the bi- functional material within the reactor.

[0052] In an exemplary embodiment, a chemical looping reactor that uses a gas switching approach and a nitrogen carrier to produce ammonia is disclosed. In embodiments disclosed herein, a lanthanum-nickel alloy, LaNis, is included in the two step reaction and functions as a nitrogen carrier for ammonia production. Alternative bi-functional materials may be employed in the two step process. Use of a gas switching approach in combination with the alloy carrier enables the production of ammonia at mild temperatures and low pressures (e.g., atmospheric pressure). Additionally, use of the alloy as a nitrogen carrier allows for the incorporation of elemental materials that promote ammonia production, hydrogen fixation, and / or nitrogen fixation, further enhancing performance of the reactor.

[0053] Referring to FIG. 1 A, aspects of an embodiment of a suitable reactor are schematically depicted. Generally, the reactor set up provides for a two-step method for producing ammonia using an alloy of LaNis. The LaNis alloy is used to take advantage of the synergistic effects of combining two ammonia promoting elements (La and Ni) in one bi-functional material. The reactor setup shown in FIG. 1 A is a fixed bed reactor that houses the LaNis alloy. The inlet gasflow to the reactor is controlled by a three-way valve to allow for rapid gas switching to operate through step 1 (FIG. IB; nitrogen fixation) and step 2 (FIG. 1C; ammonia production).

[0054] In the first step of the process (FIG. IB), nitrogen is introduced to the reactor and is fixed to the surface of the bi-functional material, LaNis alloy, through the proposed mechanisms of R2 and R3:6Ni + N2 <-> 2Ni3N (R2)2La + N2<-> 2LaN (R3)As is apparent, both the lanthanum and the nickel associated with the LaNis alloy provide nitrogen fixation functionality.

[0055] In the second step of the process, the nitrogen feed to the reactor is switched off, and hydrogen is introduced into the reactor by manipulation of the three way valve. The hydrogen will then react with the nitrogen on the surface of the bi-functional material to yield ammonia through the proposed mechanisms of R4 and R5, below.2Ni3N + 3H2<-> 6Ni + 2NH3(R4)2LaN + 3H2<-> 2La + 2NH3(RS)

[0056] As is apparent, in Step 2 of the two-step process, hydrogen reacts with the nitrogen that is fixed relative to both the lanthanum and the nickel associated with the bi-functional LaNis alloy to form ammonia.

[0057] The disclosed chemical looping ammonia synthesis enables efficient ammonia production at atmospheric pressure and mild temperatures (<300°C). Chemical looping ammonia synthesis circumvents the equilibrium constraints of a traditional Haber-Bosch process, thereby allowing for ammonia production at reduced pressures and temperatures, which can significantly lower both capital and operational costs by enabling the use of more affordable compressors and reactors than those required for the Haber-Bosch process. Furthermore, chemical looping ammonia synthesis is particularly well-suited for green ammonia production, which generates nitrogen and hydrogen in separate streams - a feature of a chemical looping ammonia synthesis reactor.

[0058] The disclosed chemical looping ammonia synthesis systems can vary in the number of steps, carrier materials, operating temperatures, and hydrogen sources, and can leverage established technologies / equipment, such as compressors, heaters, heat exchangers, and fixed bed reactors.

[0059] Each step associated with the two-step process (i.e., nitrogen fixation and ammonia production), is operated for a suitable duration. In an embodiment, the nitrogen fixation step is operated until further fixation of nitrogen by the bi-functional material falls off (e.g., as determined by monitoring gas flow from the reactor), and the ammonia production step is operated until further ammonia production falls off (e.g., as determined by monitoring gas flow from the reactor). In an embodiment, the duration of Step 1 and Step 2 can be determined based on experiential results and / or empirical calculation. After Step 2 is complete, Step 1 may be restarted.

[0060] The two-step ammonia synthesis technique was experimentally tested using a LaNis alloy. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed on the alloy to confirm composition and purity. The alloy's ability to fix nitrogen in Step 1 of the chemical loop was assessed via thermogravimetric analysis (TGA) in an atmosphere of nitrogen. A laboratory scale reactor was used to assess the LaNis alloy's ability to synthesize ammonia in the chemical loop. The outlet gases of the reactor were analyzed using gas chromatography (GC) to detect the presence of ammonia.

[0061] Qualification of the alloy was conducted. Samples of the LaNis alloy used in the experiments were purchased from ThermoFisher Scientific Chemical Inc. with a stated purity of 99.9% on a rare earth oxide (REO) basis LaNis- To validate the composition of the alloy, a sample was analyzed using X-ray diffraction (XRD) analysis. The XRD device used was a Bruker D8 Advance High Temperature X-Ray Diffractometer. The device was operated at 25 °C with a 1 mm slit from an angle of 8 to 140 degrees. The XRD profile of the sample was compared against the International Center for Diffraction Data (ICDD) database and is shown in FIG. 2. FIG. 2 shows that the XRD profile of the LaNis sample matches closely with LaNir Sno. in the ICDD database.

[0062] At the time of the analysis, the database did not include the LaNis alloy, therefore LaNir.sSno.r represents the closest elemental match in the database. The XRD peaks of La are seen most notably as the prominent peak at 42 degrees and the three clusters of peaks near 57to 64 degrees. The XRD peaks of Ni are seen at peak 30, 45 and 75. Additionally, the XRD pattern of the sample was compared with the XRD pattern of LaNis in the literature with reasonable agreement. Comparing the sample XRD profile with the third party data confirmed that the tested material was LaNis with minimal contamination.

[0063] Topology of the surface of the alloy was assessed by scanning electron microscopy (SEM) using a fresh sample of LaNis. The SEM used was a FE1 Quanta 250 FEG Field Emission Scanning Electron Microscope (ESEM) operated in partial vacuum at 25 °C. The SEM image shown in FIG. 3A shows irregularities in the shape and size of the alloy particles. FIG. 3B also shows that some particles of the alloy may have pores of considerable size. In this case, the pores were observed to be about 3.654 pm by 4.707 pm. As a result of the porosity and irregular shapes of the particles, more opportunities exist for the reaction gas to make contact with the alloy, thus improving reaction efficiency. In some embodiments, a synthetic bi-functional material with higher surface area and mass transport characteristics may be synthesized to better support the two-step ammonia synthesis reaction and the related processes. The composition of the alloy is also not exclusive. As noted above, other bifunctional materials may be employed to facilitate the two-step ammonia synthesis reaction and process functions.100641 The LaNis alloy was examined using an energy-dispersive X-ray (EDX) to determine the elements present on its surface and their distribution. Scan areas were drawn on the surface of the alloy and analyzed as shown in FIG. 4A. The EDX profile shown in FIG. 4B, identifies the presence of La and Ni in the alloy at an atomic composition of 16.4% and 71% respectively. The distribution of La and Ni is consistent with the expected distribution of the LaNis alloy with minimal contamination. The series of analyses performed on the as received sample of LaNis show that the alloy is provided with minimal contamination and has characteristics that are well-suited for gas-solid reactions.

[0065] Nitrogen fixation functionality of the LaNis alloy was evaluated by placing 200 mg of LaNis alloy in a Shimadzu TGA using an atmosphere of nitrogen. The setup of the TGA experiment is shown in FIG. 5. The temperature was programmed to increase from 25 °C to 400 °C at a ramp rate of 25 °C / min. The nitrogen was passed over the sample at a rate of 20 ml / min for the duration of the test. The weight change of the sample was measured in the TGA using a suspended balance. As shown in FIG. 5, cylinders 1 and 2 contain nitrogen and hydrogen, respectively. Element 3 is a gas flow rate controller, element 4 is the ShimadzuTGA, element 5 is a TGA furnace, and region 6 is the purge gas exit. Element 7 is a computer used for data acquisition and experimental control / programming.

[0066] To determine whether any compositional changes had taken place on the surface of the alloy, the test sample was analyzed. Following the same procedure as used for the fresh sample, the test sample was analyzed using XRD, SEM, and EDX. Temperature and weight change of the sample during the TGA experiment in an atmosphere of nitrogen are shown in FIG. 6. The XRD profiles of the alloy before and after the TGA experiment are shown in FIGS. 7A and 7B.

[0067] FIG. 7A shows a noticeable change in the number of peaks after the TGA experiment. The ICDD database identified nickel as the only element detected in the sample, while other peaks were not identified. The peaks attributed to nickel present at 30, 45, and 75 degrees remained intact after the experiment, whereas the peaks attributed to lanthanum either disappeared or shifted. This indicated that lanthanum played an active role in nitrogen fixation, potentially forming lanthanum nitride (LaN). Observably, peaks at 35, 42, 43, 57, and 68 degrees were no longer present in the sample post-experiment. Additionally, the presence of a newly observed peak at 53 degrees provides further evidence that a compositional change has occurred on the surface of the LaNis alloy.

[0068] The sample post-experiment was then analyzed using SEM and compared to the fresh sample in FIGS. 8A and 8B. After the TGA experiment, SEM images show more deposits on the surface of the material than before. An analysis of these deposits using EDX, shown in FIGS. 9A and 9B, reveals that the deposits of elemental nitrogen, carbon, and oxygen. Approximately 0.04 wt.% (0.08 mg) of the sample post-experiment was identified as elemental nitrogen. Although this represents a 0.002% conversion in nitrogen, it demonstrates the ability of the alloy to fix nitrogen at low pressure and mild temperatures. FIG. 9A depicts the scan area, and FIG. 9B shows the EDX profile and elemental analysis of the alloy after the TGA experiment in an atmosphere of nitrogen.

[0069] An example of a chemical looping ammonia synthesis system for use in a two-step synthesis of ammonia is schematically depicted in FIG. 10A. As shown in FIG. 10A, reference numbers 1, 2, 3 are gas cylinders of H2, N2 and Ar; element 4 is a gas manifold and flowmeter; element 5 is an Altimara BenchCat shown on the right; element 6 is an Agilent MicroGC 3000; element 7 is a purge line; element 8 is a computer for data acquisition and analysis.

[0070] An experimental setup according to the schematic depiction of FIG. 10A is shown in FIG. 10B. The experimental setup was used to assess the performance of the LaNis alloy in a chemical loop for ammonia synthesis. Gas cylinders of Hydrogen, Nitrogen, and Argon were supplied by Airgas, with the following concentrations: Hydrogen (3%) in Argon (97%); Nitrogen 99.99%; and Argon 99.99%. The Altimara Bench-Cat system was used to control the flow rate of feed gas to the reactor and the reactor temperature. The experiment was conducted in a U-tube connected to the Altimara Bench-Cat system, also shown, and its outlet was directed into the Agilent MicroGC 3000 unit for analysis. The data was logged on the computer using Agilent Gas Analyzer software.

[0071] The chemical loop of LaNis for ammonia synthesis was demonstrated in two experiments. In the first experiment, the chemical loop was performed isothermally and isobarically at 270 °C and 0.207 MPa, respectively. In the second experiment, the first step of the chemical loop was operated at 500 °C, and the second step was operated at 400 °C. The second experiment was also operated isobarically at 0.207 MPa.

[0072] Experiment 1 : Isothermal operation of the chemical loop

[0073] The experiment began by reducing 2 grams of LaNis in an atmosphere of hydrogen at 600°C for 1 hour in a bench-top reactor. The bench-top reactor used as the Altimara BenchCAT system, available from Altimara Instruments, of Cummings, GA. Reducing the alloy was necessary to remove surface contaminants from the sample, and to activate the material for testing. The results of the reduction step are shown in FIG. 11 A, taken from the Altimara Bench-Cat system. FIG. 11 A shows the sustained H2 flow rate into the U-tube reactor and the sustained reduction temperature of 600°C.

[0074] Immediately after the reduction step, the chemical looping procedure shown in FIG. 1 IB began. The procedure started with nitrogen fixation at a flow rate of 30 ml / min for 1 hour. After the nitrogen fixation step, argon was introduced into the reactor at 25 ml / mins for 5 minutes to purge the residual nitrogen from the reactor vessel. Thereafter, hydrogen was introduced into the reactor at a flow rate of 30 ml / mins for 1 hour. At the end of the hydrogen step, argon was used to purge the reactor vessel for a duration of 5 minutes at a flow rate of 25 ml / mins. The process was repeated for another full cycle. The operating conditions of the reduction step (FIG. 11 A) and the operating conditions of the reactor during chemical loopingwhere nitrogen, hydrogen, and argon were cycled at a constant temperature of 270°C (FIG. 11B) are as shown.

[0075] The gas composition leaving the reactor was analyzed to examine its changes overtime. As shown in FIG. 12, only nitrogen was present in the reactor during the nitrogen fixation step. In the ammonia production step, 3% hydrogen was fed into the reactor resulting in a peak in ammonia composition which declined over the time of the reaction step. It is noteworthy that the hydrogen peak did not appear until approximately ten minutes into the reaction cycle. This suggests that during this time, hydrogen is being consumed by reacting with nitrogen on the surface of the alloy. Additionally, as the hydrogen concentration in the reactor outlet increases, the ammonia concentration decreases. This further suggests that hydrogen in the reactor reacts with nitrogen on the surface of the material until the surface nitrogen is depleted. The reactor vessel was then purged with argon and nitrogen fixation was performed again. Then, as hydrogen was reintroduced to the reactor in the second ammonia production step of FIG. 12, the ammonia peak reappeared. During the reaction step, the hydrogen peak did not appear until approximately ten minutes into the reaction. FIG. 12 depicts composition at the reactor outlet during the isothermal operation of the chemical loop.

[0076] Experiment 2: High temperature operation of the chemical looping reactor

[0077] In this experiment, a fresh sample of LaNis alloy was reduced at 600 °C, then nitrogen fixation was performed at 500 °C followed by ammonia production at 400 °C. The operating conditions of this experiment are shown in FIG. 13, and the gas composition leaving the reactor is presented in FIG. 14. FIG. 14 shows the immediate production of ammonia after hydrogen was introduced into the reactor. The ammonia composition peaks approximately thirty minutes after the start of the ammonia production step, then gradually tapers off until the end of the step. After approximately fifteen minutes of operation, hydrogen appeared at the reactor outlet consistent with observations during isothermal operation of the chemical loop (Experiment 1). This result further demonstrates that hydrogen is being consumed during this step to produce ammonia. After forty minutes of operation, there was no ammonia present in the reactor outlet.

[0078] As demonstrated in the foregoing experiments, LaNis alloy is effective in fixing nitrogen at atmospheric pressure, as shown by TGA testing, and was shown to have a conversion of 0.002 wt.%. The LaNis alloy was used to synthesize ammonia in a chemical loop in both a low temperature isothermal experiment and a high temperature experiment. In bothexperiments, the presence of ammonia was confirmed using gas chromatography on the outlet gases of the reactor. The experiments thus demonstrate synthesis of ammonia under atmospheric conditions using a chemical loop of LaNis alloy at mild temperatures.

[0079] Having disclosed aspects of exemplary embodiments, some additional features and advantages are now presented.

[0080] In some embodiments, a system for synthesis of ammonia includes a chemical looping reactor that uses a gas switching approach and a nitrogen carrier to produce ammonia as introduced, and further includes a control system. FIG. 15 provides a flowchart for functionalities that may be included in a control system for synthesis of ammonia. The control system may include components such as a controller with computing capabilities, sensors (e.g., for sensing temperature, pressure, flow, humidity and other parameters), at least one power supply, motor operated valves, switches, a network (such as for communication between the controller and a sensor, switch, valve or other element of the control system), an interface (such as visual and / or auditory elements, keyboards, pointing devices and the like) for communication with a user and / or external system. The computing system may include data storage. The data storage may be configured with non-transitory machine-readable media useful for maintaining machine -readable instructions suited for operation of the system for synthesis of ammonia. The machine-readable instructions, which may be referred to commonly as “software,” may be configured for a variety of operational conditions, system designs, inputs, outputs and the like. Non-limiting examples include control of temperature, pressure, residence time, concentrations, humidity and other parameters. Control may include real-time, or near real time monitoring and adjustment. The software may be further configured to provide operators with production related data, such as conversion rates, consumption rates, output, energy demand and other similar parameters of interest.

[0081] The techniques disclosed provide for synthesis of ammonia over a wide range of temperatures. Generally, the temperature ranges suited for synthesis are limited by temperatures for decomposition of ammonia, thermodynamics and kinetics. Exemplary temperature ranges include lower temperatures, e.g., on the order of 270°C, and higher temperatures, e.g., on the order of 400°C.

[0082] In an embodiment, the synthesis loops may be fed at a preset flow rate, e.g., with 2600 kmol / h, and the ratio of nitrogen and hydrogen in the two steps may be operated at a preset ratio, e.g., a 3: 1 of nitrogen-to-hydrogen.

[0083] In an embodiment, the chemical looping reactor operates at cyclical steady state using adiabatic reactors. The feed gas is heated to a set point temperature of the chemical loop before being reacted. Ammonia is separated from the reactor outlet using a separator, and the unreacted gases are recycled back to the reactor using a compressor.

[0084] In an embodiment, a multi-reactor assembly is formed with chemical looping reactors connected in series. Feed gas may be preheated in a heat exchanger, before being fed to a heater that is set to a predetermined temperature (set-point) prior to introduction to a chemical looping reactor in the multi-reactor assembly. Ammonia is separated from the reactor outlet, and unreacted N2 and H2 are recycled, forming a synthesis loop.

[0085] Materials other than or in addition to LaNis may be suited for use as a substrate material. Generally, suitable embodiments of substrate materials include bi-functional materials. Materials other than or in addition to LaNis may be suited for use as a substrate material, e.g., NiBaH2.

[0086] In an embodiment, a LaNis sample was exposed to nitrogen at 400°C for 1 hour. In an alternative embodiment, a LaNis sample was operated in a N2-H2 chemical loop at 400°C. In a further embodiment, a LaNis sample was operated in a N2-H2 chemical loop where nitridation occurred at 400°C and hydrogenation occurred at 250°C.

[0087] Hydrogenation at a lower temperature as compared to the nitridation temperature, e.g., 250°C for hydrogenation as compared to 400°C for nitridation, has been found to reduce more nitrides and circumvent ammonia decomposition that may occur at higher temperatures.

[0088] In an embodiment, a sample of ball milled LaNis alloy was reacted in a fixed bed reactor at 250°C for four chemical looping cycles. The NH3 partial pressure increased steadily with each step of the chemical loop. The partial pressure of H2 decreased in each cycle, suggesting that H2 is consumed to produce NH3 and / or is fixed to the surface of the LaNis material. In the second N2 cycle, the partial pressure of N2 decreased significantly and an increase in NH3 partial pressure was observed. This result suggests that there was sufficient H2 on the LaNis material to form NH3.

[0089] In an embodiment, one or more ammonia synthesis promoters may be included in the chemical loop reactor(s), including sodium (Na), calcium (Ca), potassium (K), barium (Ba), ruthenium (Ru) and combinations thereof. A promoter may serve to boost the activity of the bi-functional material in ammonia synthesis. Potential promoters may be classified into structural and electronic promoters. The use of alkali metal, alkali earth metal, and rare earth metal materials as promoters for catalysts used in ammonia synthesis are known. Alkali metals are also recognized for their ability to improve the activity, selectivity, and stability of heterogeneous catalysts in chemical processes. The donation of electrons by alkali metals may facilitate the adsorption of N2 by promoting the donation of electron density to the antibonding orbital of N2.

[0090] In an embodiment, one or more support materials may be included in the chemical loop reactor(s). The support material(s) may function to reduce or prevent the bi-functional particles from clumping together (agglomeration) and increase the available surface area for nitridation and / or hydrogenation, thereby improving potential interactions between gas and solid. Exemplary supports include aluminum, lanthanum, magnesium, cerium oxide, and combinations thereof. These materials may offer an ancillary benefit to ammonia synthesis in that these materials are commonly used in ammonia synthesis catalysts.100911 The technology disclosed offers several benefits over prior art processes. First, by operating at a lower pressure and temperature, reductions in energy consumption required to produce ammonia are realized. Reduced pressure leads to a significant reduction in capital costs for the reactor and associated auxiliary equipment. Mild operating conditions of the reactor result in improved safety over prior art processes, and manufacturing is less likely to become unstable. The prior art processes are notoriously unstable due to requirements for operating conditions and the mechanism of reaction. The techniques disclosed herein use less energy, offer improved stability, increased safety, and reduced cost.

[0092] The ammonia synthesis loops were modeled using process simulation software designed for use in the chemical industry (ASPEN PLUS, available from Aspen Tech of Bedford MA)., In the modeling, chemical loop synthesis of ammonia using a bi-functional material was found to reduce synthesis cost by 90% relative to the Haber-Bosch process of equivalent size when the chemical loop synthesis is operated at low temperature (e.g., less than 300°C).

[0093] Chemical looping technology for ammonia synthesis translates to opportunities to manufacture in environments not previously available, and at reduced costs not previously achieved. As a result, the technology provides access to ammonia for many industrial, commercial and residential purposes, where such access was not previously practical.

[0094] For example, the technology disclosed herein enables a new generation of ammonia production systems. The production systems may be sized according to a particular use case. Examples of uses that may benefit from the production systems that yield low cost ammonia include: fuel cells; refrigeration systems; selective catalytic reduction (SCR) systems such as those used for NOx emission reduction; as a chemical feedstock for building many other chemicals including nitric acid, amines, and urea; in the textile industry for production of synthetic fibers like nylon as well as for dyeing and treatment. Cheaper ammonia could reduce costs in textile manufacturing; in waste and water treatment; and, in agricultural applications such as for pest control and pH adjustments of soil and water. In some of these embodiments, the production system may be configured for incorporation into the application of interest and integration into production systems therefore.

[0095] As one might imagine, an installation for ammonia production may be sized, fixed, mobile, temporary, permanent, or configured in any other way deemed appropriate by the user or operator.

[0096] With reference to FIGS. 16-18, a control system 100 includes a central computing system 126 that is in communication with each of the user devices 106 and / or imaging devices 104 and the one or more databases 108 associated with the system 100 through a communication interface 128. The communication interface 128 is configured to provide for a communication network between components of the system 100, thereby allowing data to be electronically transmitted and / or received by the components of the system 100. The system 100 may include at least one processing device 130 with a processor 132 for receiving and processing the data stored in the system 100. The system 100 may include at least one user interface 134. In some embodiments, the user interface 134 can include a display in the form of a graphical user interface (GUI) 136. The GUI 136 can be a display incorporated into the user device 106 and / or the imaging device 104 to allow for users to communicate with each other and / or the system 100 via the communication interface 128. The system 100 includes a detection module 138 forprocessing of operational parameters / data detected in connection with two-step process for ammonia synthesis within the reactor. The detection module 138 can beexecuted by the processing device 130 to implement the model 112 and analyze any images 110 received by the system 100. The detection module 138 can execute the operational parameter detection model 112 and output the results (and optionally predictions) associated with the detected operational parameters (e.g., temperature, pressure, residence time, concentration and / or humidity). In some embodiments, the detection module 138 can include multiple units or modules capable of being executed to perform respective steps of the detection and control steps of the system 100 (e.g., control of temperature, pressure, residence time, concentration and / or humidity associated with the reactor and combinations thereof).

[0097] The system 100 for control of ammonia synthesis may include data collection associated with input and output samples 102 associated with ammonia synthesis, imaging devices 104 for capturing data relative to ammonia synthesis, user(s) / user device(s) 106, central computing system 126, communication interface 128, detection module for operating parameters 138, processing device(s) 130 with processor(s) 132, user interface 134 with graphical user interface 136, and databases 108. The databases 108 may include an operational parameter detection module 112, processing guidelines 116, historical processing data 118, input image(s) 110, feedstock data 120, report(s) 124, downstream use data 122 and neural network 114.100981 FIG. 17 is a block diagram of a computing device 200 in accordance with embodiments. The computing device 200 includes one or more non-transitory computer-readable media for storing one or more computer-executable instructions or software for implementing exemplary embodiments. The non-transitory computer-readable media may include, but are not limited to, one or more types of hardware memory, non-transitory tangible media (for example, one or more magnetic storage disks, one or more optical disks, one or more flash drives), and the like. For example, memory 206 included in the computing device 200 may store computer-readable and computer-executable instructions or software for implementing exemplary embodiments of the present disclosure (e.g., instructions for operating the two-step ammonia synthesis reactor, instructions for operating the ammonia synthesis detection model, instructions for operating the processing device, instructions for operating the communication interface, instructions for operating the user interface, instructions for operating the central computing system, and combinations thereof). The computing device 200 also includes configurable and / or programmable processor 202 and associated core 204, and optionally, one or more additional configurable and / or programmable processor(s) 202’ and associated core(s) 204’(for example, in the case of computer systems having multiple processors / cores), for executing computer-readable and computer-executable instructions or software stored in the memory 206 and other programs for controlling system hardware. Processor 202 and processor(s) 202’ may each be a single core processor or multiple core (204 and 204’) processor.

[0099] Virtualization may be employed in the computing device 200 so that infrastructure and resources in the computing device 200 may be shared dynamically. A virtual machine 214 may be provided to handle a process running on multiple processors so that the process appears to be using only one computing resource rather than multiple computing resources. Multiple virtual machines may also be used with one processor. Memory 206 may include a computer system memory or random access memory, such as DRAM, SRAM, EDO RAM, and the like. Memory 206 may include other types of memory as well, or combinations thereof.

[0100] A user may interact with the computing device 200 through a visual display device 218 (e.g., a personal computer, a mobile smart device, or the like), such as a computer monitor, which may display at least one user interface 220 (e.g., a graphical user interface) that may be provided in accordance with exemplary embodiments. The computing device 200 may include other I / O devices for receiving input from a user, for example, a camera, a keyboard, microphone, a microscope, or any suitable multi-point touch interface 208, a pointing device 210 (e.g., a mouse). The keyboard 208 and the pointing device 210 may be coupled to the visual display device 218. The computing device 200 may include other suitable conventional I / O peripherals.

[0101] The computing device 200 may also include at least one storage device 224, such as a hard-drive, CD-ROM, eMMC (MultiMediaCard), SD (secure digital) card, flash drive, non-volatile storage media, or other computer readable media, for storing data and computer-readable instructions and / or software that implement exemplary embodiments of the system described herein. Exemplary storage device 224 may also store at least one database 226 for storing any suitable information required to implement exemplary embodiments. For example, exemplary storage device 224 can store at least one database 226 for storing information. The databases 226 may be updated by manually or automatically at any suitable time to add, delete, and / or update one or more items in the databases.

[0102] The computing device 200 can include a network interface 212 configured to interface via at least one network device 222 with one or more networks, for example, a LocalArea Network (LAN), a Wide Area Network (WAN) or the Internet through a variety of connections including, but not limited to, standard telephone lines, LAN or WAN links (for example, 802.11, Tl, T3, 56kb, X.25), broadband connections (for example, ISDN, Frame Relay, ATM), wireless connections, controller area network (CAN), or some combination of any or all of the above. The network interface 212 may include a built-in network adapter, a network interface card, a PCMCIA network card, Pa Cl / PCIe network adapter, an SD adapter, a Bluetooth adapter, a card bus network adapter, a wireless network adapter, a USB network adapter, a modem or any other device suitable for interfacing the computing device 200 to any type of network capable of communication and performing the operations described herein. Moreover, the computing device 200 may be any computer system, such as a workstation, desktop computer, server, laptop, handheld computer, tablet computer (e.g., the tablet computer), mobile computing or communication device (e.g., the smart phone communication device), an embedded computing platform, or other form of computing or telecommunications device that is capable of communication and that has sufficient processor power and memory capacity to perform the operations described herein.

[0103] The computing device 200 may run any operating system 216, such as any of the versions of the Microsoft® Windows® operating systems, the different releases of the Unix and Linux operating systems, any version of the MacOS® for Macintosh computers, any embedded operating system, any real-time operating system, any open source operating system, any proprietary operating system, or any other operating system capable of running on the computing device and performing the operations described herein. In exemplary embodiments, the operating system 216 may be run in native mode or emulated mode. In an exemplary embodiment, the operating system 216 may be run on one or more cloud machine instances.

[0104] FIG. 18 is a block diagram of an exemplary system environment 300 for control of ammonia synthesis in accordance with embodiments. The environment 300 can include servers 302, 304 configured to be in communication with at least one user device 306, 308 (e.g., imaging device, smart mobile device, microscope, or the like), the model 310, at least one processing device 312, at least one user interface 314, and a central computing system 318 via a communication platform 324, which can be any network over which information can be transmitted between devices communicatively coupled to the network. For example, the communication platform 324 can be the Internet, Intranet, virtual private network (VPN), widearea network (WAN), local area network (LAN), and the like. In some embodiments, the communication platform 324 can be part of a cloud environment.

[0105] The environment 300 can include repositories or databases 320, 322, which can be in communication with the servers 302, 304, as well as the at least one user device 306, 308, the model 310, at least one processing device 312, at least one user interface 314, and the central computing system 318, via the communications platform 324. In exemplary embodiments, the servers 302, 304, at least one user device 306, 308, the model 310, at least one processing device 312, at least one user interface 314, and the central computing system 318 can be implemented as computing devices (e.g., computing device 200). Those skilled in the art will recognize that the databases 320, 322 can be incorporated into at least one of the servers 302, 304. In some embodiments, the databases 320, 322 can store data relating to the ammonia synthesis model, ammonia synthesis guidelines, historical data, input images, reports, environmental data, neural network, and combinations thereof, and such data can be distributed over multiple databases 320, 322.

[0106] All statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

[0107] Various other components may be included and called upon for providing for aspects of the teachings herein. For example, additional materials, combinations of materials and / or omission of materials may be used to provide for added embodiments that are within the scope of the teachings herein. Adequacy of any particular element for practice of the teachings herein is to be judged from the perspective of a designer, manufacturer, seller, user, system operator or other similarly interested party, and such limitations are to be perceived according to the standards of the interested party.

[0108] In the disclosure hereof any element expressed as a means for performing a specified function is intended to encompass any way of performing that function including, for example, a) a combination of circuit elements and associated hardware which perform that function or b) software in any form, including, therefore, firmware, microcode or the like as set forth herein, combined with appropriate circuitry for executing that software to perform the function. Applicants thus regard any means which can provide those functionalities asequivalent to those shown herein. No functional language used in claims appended herein is to be construed as invoking 35 U.S.C. § 112(f) interpretations as “means-plus-function” language unless specifically expressed as such by use of the words “means for” or “steps for” within the respective claim.

[0109] When introducing elements of the present invention or the embodiment(s) thereof, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. Similarly, the adjective “another,” when used to introduce an element, is intended to mean one or more elements. The terms “including” and “having” are intended to be inclusive such that there may be additional elements other than the listed elements. The term “exemplary” is not intended to be construed as a superlative example but merely one of many possible examples.

Claims

CLAIMS1. A system for producing ammonia, comprising: a reactor that includes an inlet, an outlet and a reactor region, and a bi-functional material within the reactor region, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas.

2. The system of claim 1, wherein the production occurs at a temperature that is 300 degrees Celsius or less.

3. The system of claim 1, wherein the production occurs at atmospheric pressure.

4. The system of claim 1, wherein the bi-functional material is at least one of LaNi . LaNi4.8Sn0.2, NiBaH2, Ni4W, TiMox[x = 1-3], ZrMnx[x = 1-3], Ni3Ga, MnNi3, Ni3Ge, Ce2MnN3, ZrCr, ZrCr2, Ni2Mo3N, LaCoSi, LaRuSi, Cs-Ru / MgO, and Co2Mo3N.

5. The system of claim 1 , further comprising an ammonia synthesis promoter within the reactor region, wherein the ammonia synthesis promoter is selected from the group consisting of sodium (Na), calcium (Ca), potassium (K), barium (Ba), ruthenium (Ru) and combinations thereof.

6. The system of claim 1, further comprising a support material within the reactor region, wherein the support material is selected from the group consisting of aluminum, lanthanum, magnesium, cerium oxide, and combinations thereof.

7. The system of claim 1, further comprising a control system in communication with the reactor, the control system including machine-readable instructions for controlling one or more operational parameters associated with operation of the reactor for production of ammonia.

8. The system of claim 7, wherein the one or more operational parameters are selected from the group consisting of temperature, pressure, residence time, concentration and humidity.

9. A computer program product stored on non-transitory machine-readable media, the computer program product comprising machine-readable instructions for: controlling production of ammonia by operation of a reactor that includes an inlet, an outlet and a reactor region, and a bi-functional material within the reactor region, the bifunctional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas.

10. The computer program product of claim 9, wherein the controlling comprises communicating over a network comprising at least one of: a controller with computing capabilities, one or more sensors, a power supply, one or more motor operated valves, one or more switches and an interface.

11. The computer program product of claim 9, wherein the controlling comprises instructions for switching between gas supplies.

12. The computer program product of claim 9, wherein the controlling comprises instructions for monitoring the production of ammonia.

13. The computer program product of claim 12, wherein the controlling comprises instructions for operating a separator to recycle at least a portion of unreacted nitrogenous gas and unreacted hydrogenous gas.

14. The computer program product of claim 9, wherein the controlling comprises instructions for maintaining temperature of the reactor below a temperature for at least one of nitridation and decomposition of the ammonia.

15. A system for producing ammonia, comprising: a reactor that includes an inlet, an outlet and a reactor region; a bi-functional material within the reactor region, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas; and a computer program product stored on non-transitory machine-readable media, the computer program product comprising machine-readable instructions for controlling the producing by managing operation of the reactor.

16. The system of claim 15, configured for providing ammonia to one of: a fuel cell system; a refrigeration system; a selective catalytic reduction (SCR) system; a chemical feedstock production system; a system for production of synthetic fibers; a waste treatment system; a water treatment system; and an agricultural application.

17. The system of claim 15 configured as one of a fixed, mobile, temporary or permanent installation.

18. A method for producing ammonia, comprising: a. introducing a bi-functional material into a reactor, the bi-functional material configured to fix nitrogen to a surface thereof upon exposure to a nitrogenous gas and cause production of the ammonia upon exposure to a hydrogenous gas; b. introducing nitrogen to the reactor, whereby nitrogen is fixed relative to the bi- functional material; c. discontinuing introduction of nitrogen to the reactor; and d. introducing hydrogen to the reactor, whereby ammonia is produced through reaction of the hydrogen with the nitrogen fixed relative to each of the constituents of the bi-functional material.

19. The method of claim 18, wherein the order of hydrogen introduction and nitrogen introduction is reversed.

20. The method of claim 18, wherein the reactor operates at a first temperature when the nitrogen is introduced to the reactor and the reactor operates at a second temperature when the hydrogen is introduced to the reactor.

21. The method of claim 20, wherein the first temperature is the same as the second temperature.

22. The method of claim 20, wherein the first temperature is greater than the second temperature.

23. The method of claim 20, wherein the first temperature is between 200°C and 900°C.

24. The method of claim 20, wherein the second temperature is between 100°C and 400°C.

25. The method of claim 18, wherein steps (b) - (d) are performed under isobaric conditions.

26. The method of claim 18, wherein the bi-functional material includes an ammonia synthesis promoter selected from the group consisting of sodium (Na), calcium (Ca), potassium (K), barium (Ba), ruthenium (Ru) and combinations thereof.

27. The method of claim 18, wherein the bi-functional material includes a support material selected from the group consisting of aluminum, lanthanum, magnesium, cerium oxide, and combinations thereof.

28. The method of claim 18, wherein a control system in communication with the reactor controls one or more operational parameters associated with operation of the reactor for production of ammonia.

29. The method of claim 28, wherein the one or more operational parameters are selected from the group consisting of temperature, pressure, residence time, concentration and humidity.

30. The method of claim 18, further comprising providing ammonia to one of: a fuel cell system; a refrigeration system; a selective catalytic reduction (SCR) system; a chemical feedstock production system; a system for production of synthetic fibers; a waste treatment system; a water treatment system; and an agricultural application.

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