Ammonia decomposition on nickel-based catalysts

Abstract

The present invention relates to a method for preparing H2 from NH3. NH3 is introduced into a fixed-bed reactor at a gas temperature in the range of 550 to 850°C, where the NH3 is partially decomposed into H2 and N2 on an NH3 decomposition catalyst. The resulting gas mixture is discharged from the fixed-bed reactor at a gas temperature in the range of 300 to 700°C, heated to a temperature in the range of 550 to 700°C, and then introduced into a tubular reactor, where further NH3 is decomposed into H2 and N2 on a nickel-based NH3 decomposition catalyst. The resulting gas mixture is discharged from the tubular reactor at a gas temperature in the range of 550 to 750°C.

Description

[Technical Field]

[0001] Priority is claimed from Luxembourg Patent Application No. 103169 dated July 13, 2023.

[0002] The present invention relates to a process for producing H2 from NH3. This involves introducing NH3 into a fixed-bed reactor at a gas temperature in the range of 550–850°C, where the NH3 is partially decomposed into H2 and N2 on an NH3 decomposition catalyst. The gas mixture thus obtained is discharged from the fixed-bed reactor at a gas temperature in the range of 300–700°C, heated to a temperature in the range of 550–700°C, and then introduced into a tubular reactor, where further NH3 is decomposed into H2 and N2 on a nickel-based NH3 decomposition catalyst. The gas mixture thus obtained is discharged from the tubular reactor at a gas temperature in the range of 550–750°C. [Background technology]

[0003] H2 can be obtained from H2O using renewable energy and then converted to NH3 using N2. NH3 can be stored and transported much more safely than H2. NH3 can then be broken down again into H2 and N2. After being separated from N2, H2 finds a wide range of industrial applications.

[0004] The decomposition of NH3 into N2 and H2 is an endothermic reaction in which the molar amount doubles (2NH3 → N2 + 3H2) (ΔH° = 45.9 kJ·mol). -1 Therefore, the reaction is generally favored at high temperature and low pressure. The higher the pressure, the higher the temperature must be to achieve a satisfactory reaction yield. Numerous materials have been proposed as catalysts for decomposition, and these are active at different temperatures (see, for example, Il. Lucentini et al., Review of the Decomposition of Ammonia to Generate Hydrogen, Ind.Eng.Chem.Res.2021,60,18560-18611).

[0005] Catalytic decomposition of NH3 yields a product gas containing H2 in a mixture with N2 and possibly other gaseous components, such as unconverted NH3. However, since many industrial applications require high-purity H2, the product gas needs to be purified before H2 can be sent to industrial applications. Washing of H2 is basically possible by various methods, such as cryogenic membrane methods, but washing by pressure swing adsorption is particularly economically feasible on an industrial scale.

[0006] U.S. Patent No. 4,704,267 relates to the production of high-purity hydrogen from liquid anhydrous ammonia. Ammonia is evaporated and then separated into its components. The resulting decomposition gas stream is supplied to an adiabatic metal hydride washing unit to absorb hydrogen present in the stream. The adsorbed hydrogen is then recovered as a high-purity product.

[0007] U.S. Patent Application Publication No. 2020 / 0123006 relates to a process for producing a nitrogen and hydrogen-containing product gas from ammonia, the process comprising the steps of: non-catalytic partial oxidation of ammonia with an oxygen-containing gas to obtain a process gas containing nitrogen, water, a certain amount of nitrogen oxides and a residual amount of ammonia; cracking at least a portion of the residual ammonia in the process gas into hydrogen and nitrogen by contact with a nickel-containing catalyst, and simultaneously reducing a certain amount of nitrogen oxides to nitrogen and water by reaction with a portion of the hydrogen formed during the cracking of the process gas by contact with the nickel-containing catalyst; and extracting the hydrogen and nitrogen-containing product gas.

[0008] French Patent Application Publication No. 1469045 relates to an apparatus which may consist of a preheater to which ammonia is supplied, a tube bundle containing a catalyst for cracking ammonia, and a cell for washing hydrogen by diffusion, these being connected to each other and located in a single housing including heating means.

[0009] Chinese Patent Application Publication No. 111957270 relates to an ammonia decomposition apparatus comprising an ammonia decomposition unit and a combustion unit acting on the ammonia decomposition unit. Ammonia enters the ammonia decomposition unit through a first inlet for purified gas to carry out the ammonia decomposition reaction. The resulting mixed gas is discharged through a second outlet for purified gas and then enters the combustion unit through a second inlet for purified gas. The mixed gas contains nitrogen, hydrogen, and undecomposed ammonia. The mixed gas enters the combustion unit to supply heat for the ammonia decomposition reaction in the ammonia decomposition unit, achieving heat self-sufficiency in the hydrogen production system by ammonia decomposition. No additional fuel is required for energy supply, and the cost of the hydrogen production system by ammonia decomposition is reduced.

[0010] Chinese Patent Application Publication No. 112742310 relates to an ammonia decomposition reactor and an ammonia decomposition process. The apparatus comprises a heater or pre-reactor and a reactor, the reactor being hollow, and the reactor including the arrangement of a first separation plate, several tubes, a gas distributor and a second separation plate. The arrangement of the pre-reactor allows the catalytic combustion reaction to be initiated at room temperature, raising the reactor temperature to 350-600°C to carry out the ammonia decomposition reaction, or the reactor is heated using a heater, the catalytic combustion reaction is initiated after the reactor temperature reaches 200-350°C, the heater is turned off, and the reactor temperature is further raised to 350-600°C by operation. The catalytic combustion reaction releases heat and the ammonia decomposition reaction takes place.

[0011] Chinese Patent Application Publication No. 113896168 relates to a two-stage process for producing hydrogen or reduced gas by cracking ammonia, comprising the steps of: completely gasifying and heating liquid ammonia as a raw material in a heat exchange gasification system, then entering a first-stage heat exchange ammonia cracking reaction system to carry out a partial ammonia cracking reaction; and the reaction gas from the first-stage heat exchange ammonia cracking reaction system entering a second-stage high-temperature ammonia cracking reaction system to carry out a residual ammonia cracking reaction. The high-temperature ammonia cracking reaction gas from the second stage is then continuously entered into the first-stage heat exchange ammonia cracking reaction system and heat exchange gasification system to gradually recover heat and obtain reduced gas.

[0012] Japanese Patent Publication No. 2023073692 relates to a method for obtaining hydrogen by decomposing ammonia. The ammonia decomposition step includes heating with combustion gas, passing ammonia through a heat exchanger reactor 3 at a pressure of 1.5 MPa to 7 MPa, and contacting a catalyst containing Ru at a temperature of 400°C to 550°C while heating to decompose the ammonia into nitrogen and hydrogen; contacting the gas obtained in the previous step with a hydrogen permeable membrane at a temperature of 300°C to 550°C to separate the hydrogen; reducing the pressure of the gas containing unconverted ammonia after hydrogen removal to 0.3 MPa or less; adding an oxygen-containing gas to the decomposition gas and decomposing the ammonia by contacting it with a catalyst containing at least one metal selected from the group consisting of Ru, Rh, and Pd; and a combustion step by adding an oxygen-containing gas to the gas obtained in the previous step.

[0013] International Publication No. 2011 / 107279 relates to an ammonia-based hydrogen production reactor comprising an ammonia cracking chamber having an ammonia cracking catalyst, an internal combustion chamber having a combustion catalyst or oxidation catalyst in thermal contact with the ammonia cracking chamber, an ammonia gas preheating chamber, and an outer shell ring for recovering heat from combustion products exiting the combustion chamber, wherein the cracking chamber, internal combustion chamber, preheating chamber, and heat recovery shell ring are concentrically arranged.

[0014] International Publication No. 2012 / 090739 relates to a hydrogen generator comprising a decomposition device that produces hydrogen by decomposing a compound containing hydrogen atoms and nitrogen atoms, a compound supply device that supplies the compound to the decomposition device, and an oxygen supply device that supplies oxygen to the decomposition device.

[0015] International Publication No. 2020 / 095467 relates to a hydrogen gas generator comprising an evaporator for heating liquid ammonia to produce ammonia gas; a main pyrolysis unit for combustion of a fuel gas, which heats the ammonia gas produced in the evaporator to decompose it into nitrogen gas and hydrogen gas; a cooler for cooling the gas produced by decomposition, which includes the nitrogen gas and hydrogen gas produced by decomposition in the main pyrolysis unit; and a separator (8) for separating hydrogen gas from the gas produced and cooled by decomposition.

[0016] International Publication No. 2021 / 257944 relates to the recovery of hydrogen from an ammonia cracking process in which the cracking gas is washed within a PSA unit. Using a membrane separator for the PSA off-gas improves the recovery rate.

[0017] International Publication No. 2022 / 096529 relates to a method for cracking ammonia, producing hydrogen, and generating electric current, including electrolysis of water in supplied ammonia, evaporation, preheating, and cracking of ammonia using an ammonia synthesis catalyst at low temperatures.

[0018] International Publication No. 2022 / 189560 relates to a method and system for producing hydrogen products from ammonia, comprising at least one pre-cracking reactor, which may include an adiabatic pre-cracking reactor, and an ammonia cracking reactor, which includes an electroheated reactor, configured to receive an ammonia feed stream and thereby produce a partially converted ammonia feed stream, ammonia, hydrogen, and nitrogen. The reactor is configured to receive a partially converted ammonia feed stream or ammonia feed stream for the production of an off-gas stream containing hydrogen and nitrogen and any further any unconverted ammonia, and a hydrogen recovery unit is configured to receive an off-gas stream and produce hydrogen products and an off-gas stream containing hydrogen, nitrogen, and any unconverted ammonia.

[0019] International Publication No. 2022 / 243410 relates to a method for synthesizing hydrogen via catalytic cracking of ammonia, wherein an ammonia-containing stream is subjected to a catalytic cracking step in the presence of heat to obtain a combustion gas, with or without water, and a thermally cracked stream containing nitrogen, hydrogen, and optionally residual ammonia, and the thermally cracked stream is subjected to a hydrogen recovery step to obtain a high-purity hydrogen stream.

[0020] International Publication No. 2022 / 265647 relates to the recovery of renewable hydrogen products from an ammonia cracking method, in which the cracked gas is purified in a first PSA unit to reduce the carbon intensity of the renewable hydrogen products, and at least a portion of the first PSA tail gas is recycled as fuel.

[0021] International Publication No. 2022 / 265648 relates to the removal of NOx impurities from flue gas produced by selective catalytic reduction (SCR) using an aqueous ammonia solution generated by cooling compressed off-gas from a hydrogen PSA apparatus for cleaning cracked gas.

[0022] International Publication No. 2022 / 265649 relates to the reduction of water content in ammonia used in ammonia cracking processes, enabling the use of water-incompatible cracking catalysts. The water removal process can also be used for the recovery and reuse of ammonia from cracking gases.

[0023] International Publication No. 2022 / 265650 relates to an ammonia cracking process in which cracking gas is purified in a PSA system. Residual ammonia in the first cracking gas is converted to further hydrogen and nitrogen by supplying PSA tail gas or a gas derived therefrom to a secondary cracking reactor and further processing the second cracking gas.

[0024] International Publication No. 2022 / 265651 relates to a process for removing residual ammonia from a hydrogen PSA system using a non-zeolite adsorbent such as activated carbon, activated alumina, or silica gel from ammonia cracking gas. [Prior art documents] [Patent Documents]

[0025] [Patent Document 1] U.S. Patent No. 4704267 [Patent Document 2] U.S. Patent Application Publication No. 2020 / 0123006 [Patent Document 3] French Patent Application Publication No. 1469045 [Patent Document 4] Chinese Patent Application Publication No. 111957270 Specification [Patent Document 5] Chinese Patent Application Publication No. 112742310 Specification [Patent Document 6] Chinese Patent Application Publication No. 113896168 Specification [Patent Document 7] Japanese Patent Publication No. 2023073692 [Patent Document 8] International Publication No. 2011 / 107279 [Patent Document 9] International Publication No. 2012 / 090739 [Patent Document 10] International Publication No. 2020 / 095467 [Patent Document 11] International Publication No. 2021 / 257944 [Patent Document 12] International Publication No. 2022 / 096529 [Patent Document 13] International Publication No. 2022 / 189560 [Patent Document 14] International Publication No. 2022 / 243410 [Patent Document 15] International Publication No. 2022 / 265647 [Patent Document 16] International Publication No. 2022 / 265648 [Patent Document 17] International Publication No. 2022 / 265649 [Patent Document 18] International Publication No. 2022 / 265650 [Patent Document 19] International Publication No. 2022 / 265651 [Non-patent literature]

[0026] [Non-Patent Document 1] Il.Lucentini et al.,Review of the Decomposition of Ammonia to Generate Hydrogen,Ind.Eng.Chem.Res.2021,60,18560-18611 [Overview of the project] [Problems that the invention aims to solve]

[0027] Conventional methods for obtaining H2 from NH3 are unsatisfactory in all respects, and an improved method that can be economically implemented on an industrial scale is needed. There is a need to develop a suitable reactor design for producing H2 from NH3. A combustion tubular reactor, similar to a steam reformer, is one theoretical option for endothermic or quasi-isothermal high-temperature reactions. However, the industrial application of steam reforming to the catalytic decomposition of NH3 is fraught with various obstacles.

[0028] The object of the present invention is to provide an improved method for producing H2 from NH3. This method must be economically viable in terms of energy balance and yield, and must be implementable on an industrial scale. It should be possible to use an NH3 decomposition catalyst with a sufficient service life at an acceptable cost under given reaction conditions. [Means for solving the problem]

[0029] This objective is achieved by the subject matter of the claims.

[0030] It has been found that washing the product gas by pressure swing adsorption requires a product gas pressure of at least 10 bar a, preferably at least 20 bar a, to function economically. However, such a pressure itself is undesirable for catalytic decomposition of NH3. Performing catalytic decomposition at lower pressures and subsequent compression of the product gas before pressure swing adsorption is uneconomical.

[0031] Surprisingly, it has now been discovered that there are reaction methods that can be carried out even at sufficiently high pressures, firstly, achieving good yields of the decomposition reaction, and secondly, allowing for economically viable subsequent washing by pressure swing adsorption without upstream compression of the product gas.

[0032] The reaction scheme in two series-connected reactors has been found to be advantageous, particularly when the first reactor is a fixed-bed reactor operating essentially adiabatically without external heat supply, and the second reactor is designed as a combustion tubular reactor, similar to a primary reformer (steam reformer). This allows for miniaturization of the combustion tubular reactor. Consequently, it is also possible to limit the amount of heat present in the combustion air, i.e., the off-gas from the combustion system for the tubular reactor, that must be returned to the process for an economically viable process scheme so as not to be released unused into the environment.

[0033] Here, it was found that the temperatures at the inlet (T1) and outlet (T2) of the first reactor, the temperatures at the inlet (T3) and outlet (T4) of the second reactor, the degree of partial conversion in the first reactor, and the configuration of the second reactor interact with each other and can influence each other in a way that allows for the optimization of the economic feasibility of the process.

[0034] In the case of an upstream fixed-bed reactor, the inlet temperature (T1) and outlet temperature (T2) are limited upward by the allowable preheating and downward by the catalyst activity. Depending on the type of one or more catalysts, the operating range is preferably about 650°C to about 350°C.

[0035] In the case of downstream combustion tubular reactors, a parabolic profile of energy supply through the tube wall preferably significantly reduces catalyst demand compared to a linear profile of energy supply. Ceiling combustion with a relatively short flame has been found to be the optimal solution for energy supply. Preferably, downstream combustion tubular reactors are designed with inlet temperatures in the range of approximately 550°C to 700°C. At higher temperatures, the reaction consumes more energy than can be replenished through the tube wall as a result of combustion. Furthermore, special materials with shorter service lives are required for the apparatus, and the reduction in catalyst volume is minimal. Preferably, downstream combustion tubular reactors are designed so that their outlet temperature is higher than their inlet temperature. In this way, something close to equilibrium transformation can be achieved. Lower outlet temperatures result in lower conversion rates, and therefore higher gas loading, and an increased reactor volume is required.

[0036] In particular, reaction conditions were found that could achieve an H2 conversion rate of over 98%, resulting in a sufficiently low residual amount of unconverted NH3 in the product gas, making it possible to separate H2 by pressure swing adsorption without further measures.

[0037] A first aspect of the present invention relates to a method for producing H2 from NH3, and includes the following steps.

[0038] (a) Supplying a reaction gas that contains or is essentially made from NH3, (b) Heat the reaction gas to a gas temperature T1 in the range of 550 to 850°C at a pressure p1 of at least 10 bar a. (c) Introducing the heated reaction gas at gas temperature T1 and pressure p1 into at least one fixed-bed reactor containing at least one catalyst bed containing or essentially consisting of an NH3 decomposition catalyst. (d) Partially decomposing NH3 on at least one catalyst bed in at least one fixed-bed reactor to obtain an intermediate product gas containing or essentially consisting of H2, N2 and undecomposed NH3, and (e) Discharge intermediate product gas from at least one fixed-bed reactor at a gas temperature T2 in the range of 300 to 700°C and a pressure p2 of at least 10 bar a. (f) Heat the intermediate product gas to a gas temperature T3 in the range of 550-700°C at a pressure p3 of at least 10 bar a. (g) The heated intermediate product gas is introduced into at least one tubular reactor comprising a number of parallel tubes, each containing at least one catalyst bed, which is heated by the combustion of a combustion gas at a gas temperature T3 and pressure p3 and contains or essentially consists of a nickel-based NH3 decomposition catalyst. (h) Decomposing NH3 in at least one tubular reactor on a catalyst bed to obtain a product gas containing H2, N2 and some undecomposed NH3, or essentially consisting of H2, N2 and some undecomposed NH3, and (i) Discharge the product gas from at least one tubular reactor at a gas temperature T4 in the range of 550 to 750°C and a pressure p4 of at least 10 bar a.

[0039] In step (a) of the method of the present invention, a reaction gas containing or essentially consisting of NH3 is supplied.

[0040] In a preferred embodiment, NH3 is stored in liquid form at low temperatures and is therefore essentially pure, and thus the reaction gas preferably consists essentially of NH3.

[0041] NH3 is preferably synthetic NH3 produced from N2 and H2, where H2 is preferably obtained by electrolysis of water, and the power for electrolysis is preferably obtained from renewable energy, preferably solar energy (especially photovoltaic power) and / or wind energy.

[0042] In step (b) of the method of the present invention, the reaction gas supplied in advance in step (a) is heated to a gas temperature T1 in the range of 550 to 850°C at a pressure p1 of at least 10 bar a.

[0043] T1 is preferably in the range of 550 to 700°C.

[0044] Preferably, T1 is at least 595°C, preferably at least 600°C, more preferably at least 605°C, even more preferably at least 610°C, most preferably at least 615°C, and particularly at least 620°C. Preferably, T1 is at least 625°C, preferably at least 630°C, more preferably at least 635°C, even more preferably at least 640°C, most preferably at least 645°C, and particularly at least 650°C.

[0045] Preferably, T1 is a maximum of 710°C, preferably a maximum of 705°C, more preferably a maximum of 700°C, even more preferably a maximum of 695°C, most preferably a maximum of 690°C, and particularly a maximum of 685°C. Preferably, T1 is a maximum of 680°C, preferably a maximum of 675°C, more preferably a maximum of 670°C, even more preferably a maximum of 665°C, most preferably a maximum of 660°C, and particularly a maximum of 655°C.

[0046] Preferably, p1 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and especially at least 22 bar a.

[0047] Preferably, p1 is a maximum of 80 bar a, preferably a maximum of 70 bar a, more preferably a maximum of 60 bar a, even more preferably a maximum of 50 bar a, most preferably a maximum of 40 bar a, and especially a maximum of 30 bar a.

[0048] In step (c) of the method of the present invention, the reaction gas preheated in step (b) is introduced at a gas temperature T1 and pressure p1 into at least one fixed-bed reactor containing at least one catalyst bed which contains or is essentially made from an NH3 decomposition catalyst.

[0049] At least one catalyst bed of the fixed bed reactor is preferably not heated.

[0050] At least one fixed bed reactor is preferably operated adiabatically.

[0051] The NH₃ decomposition catalyst in at least one catalyst bed of the fixed bed reactor is a nickel-based catalyst, preferably supported nickel.

[0052] Preferably, the nickel-based NH₃ decomposition catalyst in at least one catalyst bed of the fixed bed reactor for the decomposition of NH₃ has an (apparent) activation energy of 240 kJ·mol -1 or less, preferably 230 kJ·mol -1 or less, more preferably 220 kJ·mol -1 or less, even more preferably 210 kJ·mol -1 or less, most preferably 20 kJ·mol -1 or less, particularly 190 kJ·mol -1 or less.

[0053] Preferably, the nickel-based NH₃ decomposition catalyst in at least one catalyst bed of the fixed bed reactor for the decomposition of NH₃ has an (apparent) activation energy of 180 kJ·mol -1 or less, preferably 170 kJ·mol -1 or less, more preferably 160 kJ·mol -1 or less, even more preferably 150 kJ·mol -1 or less, most preferably 140 kJ·mol -1 or less, particularly 130 kJ·mol -1 or less.

[0054] In a preferred embodiment, at least one fixed bed reactor includes a first catalyst bed containing a first NH₃ decomposition catalyst and a second catalyst bed containing a second NH₃ decomposition catalyst, and the second catalyst bed is disposed downstream of the first catalyst bed in the flow direction of the reaction gas or the intermediate product gas.

[0055] In a preferred embodiment, the first NH3 decomposition catalyst and the second NH3 decomposition catalyst are the same.

[0056] In other preferred embodiments, the first NH3 decomposition catalyst and the second NH3 decomposition catalyst are different.

[0057] Preferably, the second NH3 decomposition catalyst has a higher (apparent) activation energy for NH3 decomposition than the first NH3 decomposition catalyst.

[0058] In a preferred embodiment, at least one catalyst bed of the fixed-bed reactor essentially takes the form of a cylinder through which the reaction gas or intermediate product gas flows axially.

[0059] In another preferred embodiment, at least one catalyst bed of the fixed-bed reactor essentially takes the form of a hollow cylinder through which the reaction gas or intermediate product gas flows radially.

[0060] Preferably, at least one catalyst bed of the fixed-bed reactor has an essentially circular cross-section having a diameter of at least 80 cm, preferably at least 100 cm, preferably at least 120 cm, more preferably at least 140 cm, preferably at least 160 cm, and especially at least 180 cm.

[0061] Preferably, in the flow direction of the reaction gas or intermediate product gas, at least one catalyst bed of the fixed-bed reactor has a length of at least 80 cm, preferably at least 100 cm, preferably at least 120 cm, more preferably at least 140 cm, most preferably at least 160 cm, and especially at least 180 cm.

[0062] Preferably, at least one catalyst bed of the fixed-bed reactor is used for 5,000 to 25,000 hours. -1 Preferably 10,000 to 20,000 hours -1 more preferably 12,500 to 17,500 hours -1 It has spatial velocities within the range of [this range].

[0063] In step (d) of the method of the present invention, NH3 is partially decomposed on at least one catalyst bed in at least one fixed-bed reactor to obtain an intermediate product gas comprising or essentially consisting of H2, N2 and undecomposed NH3.

[0064] Preferably, in step (d), the conversion rate of the decomposed NH3 is at least 12.5%, preferably at least 15%, more preferably at least 17.5%, even more preferably at least 20%, most preferably at least 22.5%, and particularly at least 25%, based on the amount of NH3 initially present in the reaction gas supplied in step (a).

[0065] Preferably, in step (d), the conversion rate of NH3 is 42.5% or less, preferably 40% or less, more preferably 37.5% or less, even more preferably 35% or less, most preferably 32.5% or less, and particularly 30% or less, based on the amount of NH3 initially present in the reaction gas supplied in step (a) in each case.

[0066] In step (e) of the method of the present invention, the intermediate product gas obtained in advance in step (d) is discharged from at least one fixed-bed reactor at a gas temperature T2 in the range of 300 to 700°C and a pressure p2 of at least 10 bar a.

[0067] T2 is preferably in the range of 300 to 690°C.

[0068] Preferably, T2 is at least 300°C, preferably at least 310°C, more preferably at least 320°C, even more preferably at least 330°C, most preferably at least 340°C, and particularly at least 350°C. Preferably, T2 is at least 400°C, preferably at least 410°C, more preferably at least 420°C, even more preferably at least 430°C, most preferably at least 440°C, and particularly at least 450°C.

[0069] Preferably, T2 is a maximum of 510°C, preferably a maximum of 500°C, more preferably a maximum of 490°C, even more preferably a maximum of 480°C, most preferably a maximum of 470°C, and particularly a maximum of 460°C. Preferably, T2 is a maximum of 410°C, preferably a maximum of 400°C, more preferably a maximum of 390°C, even more preferably a maximum of 380°C, most preferably a maximum of 370°C, and particularly a maximum of 360°C.

[0070] Preferably, p2 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and especially at least 22 bar a.

[0071] Preferably, p2 is a maximum of 80 bar a, preferably a maximum of 70 bar a, more preferably a maximum of 60 bar a, even more preferably a maximum of 50 bar a, most preferably a maximum of 40 bar a, and especially a maximum of 30 bar a.

[0072] Preferably, T1 > T2.

[0073] Preferably, the magnitude of the relative temperature difference |T1-T2| is at least 50°C, more preferably at least 75°C, even more preferably at least 100°C, most preferably at least 125°C, and particularly at least 150°C. Preferably, the magnitude of the relative temperature difference |T1-T2| is at least 175°C, more preferably at least 200°C, even more preferably at least 225°C, most preferably at least 250°C, and particularly at least 275°C.

[0074] In a preferred embodiment, -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃, and -T2 is within the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, and most preferably 450±10℃.

[0075] In another preferred embodiment, -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃, and -T2 is within the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, and most preferably 350±10℃.

[0076] Preferably, p1 > p2.

[0077] Preferably, the magnitude of the relative pressure difference |p1-p2| is a maximum of 6 bar, preferably a maximum of 5 bar, more preferably a maximum of 4 bar, even more preferably a maximum of 3 bar, most preferably a maximum of 2 bar, and especially a maximum of 1 bar.

[0078] Preferably, T3 > T2.

[0079] Preferably, the magnitude of the relative temperature difference |T3-T2| is at least 20°C, more preferably at least 40°C, even more preferably at least 60°C, most preferably at least 80°C, and especially at least 100°C.

[0080] Preferably, the magnitude of the relative temperature difference |T3-T2| is at least 110°C, more preferably at least 120°C, even more preferably at least 130°C, most preferably at least 140°C, and particularly at least 150°C.

[0081] In a preferred embodiment, -T2 is in the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, and most preferably 450±10℃, and -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃, and

[0082] In another preferred embodiment, -T2 is in the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, and most preferably 350±10℃, and -T3 is within the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃.

[0083] Preferably, p3 > p2.

[0084] Preferably, the magnitude of the relative pressure difference |p3-p2| is a maximum of 6 bar, preferably a maximum of 5 bar, more preferably a maximum of 4 bar, even more preferably a maximum of 3 bar, most preferably a maximum of 2 bar, and especially a maximum of 1 bar.

[0085] In a preferred embodiment, T3 > T1.

[0086] In another preferred embodiment, T3 <T1である。

[0087] Preferably, the magnitude of the relative temperature difference |T1-T3| is at least 5°C, more preferably at least 10°C, even more preferably at least 15°C, most preferably at least 20°C, and particularly at least 25°C. Preferably, the magnitude of the relative temperature difference |T1-T3| is at least 30°C, more preferably at least 35°C, even more preferably at least 40°C, most preferably at least 45°C, and particularly at least 50°C.

[0088] Preferably, the magnitude of the relative temperature difference |T1-T3| is a maximum of 50°C, more preferably a maximum of 45°C, even more preferably a maximum of 40°C, most preferably a maximum of 35°C, and particularly a maximum of 30°C. Preferably, the magnitude of the relative temperature difference |T1-T3| is a maximum of 25°C, more preferably a maximum of 20°C, even more preferably a maximum of 15°C, most preferably a maximum of 10°C, and particularly a maximum of 5°C.

[0089] In a preferred embodiment, -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃, and -T3 is within the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃.

[0090] Preferably, p3 <p1である。

[0091] Preferably, the magnitude of the relative pressure difference |p3-p1| is a maximum of 6 bar, preferably a maximum of 5 bar, more preferably a maximum of 4 bar, even more preferably a maximum of 3 bar, most preferably a maximum of 2 bar, and especially a maximum of 1 bar.

[0092] Preferably, the nickel-based NH3 decomposition catalyst in at least one catalyst bed of each of the numerous tubes in the tubular reactor is supported nickel.

[0093] Preferably, the nickel-based NH3 decomposition catalyst in at least one catalyst bed of each of the numerous tubes of the tubular reactor for NH3 decomposition has a maximum output of 240 kJ·mol. -1 Preferably 230 kJ·mol -1 More preferably, 220 kJ·mol -1 More preferably, 210 kJ·mol -1 Below, the most preferred value is 200 kJ·mol. -1 The following, in particular, 190 kJ·mol -1 It has the following (apparent) activation energies.

[0094] Preferably, the nickel-based NH3 decomposition catalyst in at least one catalyst bed of each of the numerous tubes of the tubular reactor for NH3 decomposition has a maximum output of 180 kJ·mol. -1 Preferably 170 kJ·mol -1 More preferably, 160 kJ·mol -1 More preferably, 150 kJ·mol -1 Below, the most preferred amount is 140 kJ·mol. -1 The following, in particular, 130 kJ·mol -1 It has the following (apparent) activation energies.

[0095] Preferred support materials include Al2O3, MgO, SiO2, mesoporous SiO2 (e.g., MCF-17, MCM-41, SBA-15), zeolite (e.g., HY, H-ZSM-5), BaMnO3, BaTiO3, BaZrO3, CaMnO3, CaTiO3, CaZrO3, CeO2, Gd2O3, GdAlO3, KNbO3, La2O3, LaAlO3, MnO2, and N The group is selected from aNbO3, Nb2O5, Sm2O3, SmAlO3, SrMnO3, SrTiO3, SrZrO3, TiO2, Y2O3, ZrO2, carbon (e.g., CNT, SWCNT, AX-21, MSC-30, MESO-C, GNP, activated carbon, graphene, graphene oxide), attapulgite, hydrocalmite, sepiolite, and mixtures thereof.

[0096] In step (f) of the method of the present invention, the intermediate product gas is heated to a gas temperature T3 in the range of 550 to 700°C at a pressure p3 of at least 10 bar a.

[0097] T3 is preferably in the range of 560 to 700°C.

[0098] Preferably, T3 is at least 590°C, preferably at least 595°C, more preferably at least 600°C, even more preferably at least 605°C, most preferably at least 610°C, and particularly at least 615°C.

[0099] Preferably, T3 is a maximum of 650°C, preferably a maximum of 645°C, more preferably a maximum of 640°C, even more preferably a maximum of 635°C, most preferably a maximum of 630°C, and particularly a maximum of 625°C.

[0100] Preferably, p3 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and especially at least 22 bar a.

[0101] Preferably, p3 is a maximum of 80 bar a, preferably a maximum of 70 bar a, more preferably a maximum of 60 bar a, even more preferably a maximum of 50 bar a, most preferably a maximum of 40 bar a, and especially a maximum of 30 bar a.

[0102] In step (g) of the method of the present invention, the intermediate product gas preheated in step (f) is heated by combustion of a combustion gas at a gas temperature T3 and pressure p3 and introduced into at least one tubular reactor comprising a number of parallel tubes, each containing at least one catalyst bed containing or essentially consisting of a nickel-based NH3 decomposition catalyst.

[0103] Preferably, the number of parallel tubes in the tubular reactor is at least 50, preferably at least 100, more preferably at least 150, even more preferably at least 200, most preferably at least 250, and especially at least 300.

[0104] Preferably, each of the numerous parallel tubes of the tubular reactor has a length L of at least 5.5 m, preferably at least 6.0 m, more preferably at least 6.5 m, even more preferably at least 8 m, most preferably at least 7.0 m, and especially at least 7.5 m in the flow direction of the intermediate product gas or product gas. R It holds.

[0105] Preferably, the numerous parallel tubes of the tubular reactor have an essentially circular cross-section with an inner diameter of at least 5.0 cm, preferably at least 5.5 cm, more preferably at least 6.0 cm, even more preferably at least 6.5 cm, most preferably at least 7.0 cm, and especially at least 7.5 cm in the flow direction of the intermediate product gas or product gas.

[0106] Preferably, the numerous parallel tubes of the tubular reactor have an essentially circular cross-section with an inner diameter of up to 12 cm, preferably up to 11 cm, more preferably up to 10 cm, even more preferably up to 9.5 cm, preferably up to 9.0 cm, and especially up to 8.5 cm, in the flow direction of the intermediate product gas or product gas.

[0107] Preferably, the catalyst bed of the tubular reactor is used for 500 to 15,000 hours. -1 Preferably 1000 to 10000 hours -1 , more 2500~7500h -1 It has the total spatial velocity within the range of [this].

[0108] Preferably, at least one catalyst bed in a fixed-bed reactor has a larger overall space velocity than the catalyst bed in a tubular reactor.

[0109] In step (h) of the method of the present invention, NH3 is decomposed on a catalyst bed in at least one tubular reactor to obtain a product gas containing H2, N2 and some undecomposed NH3, or essentially consisting of H2, N2 and some undecomposed NH3.

[0110] Preferably, in step (h), the conversion rate of the decomposed NH3 is at least 90%, preferably at least 92.5%, more preferably at least 95%, even more preferably at least 96%, most preferably at least 97%, and particularly at least 98%, based on the amount of NH3 initially present in the reaction gas supplied in step (a) in each case.

[0111] In step (i) of the method of the present invention, the product gas obtained in advance in step (h) is discharged from at least one tubular reactor at a gas temperature T4 in the range of 550 to 750°C and a pressure p4 of at least 10 bar a.

[0112] T4 is preferably in the range of 560 to 750°C.

[0113] Preferably, T4 is at least 650°C, preferably at least 655°C, more preferably at least 660°C, even more preferably at least 665°C, most preferably at least 670°C, and particularly at least 675°C.

[0114] Preferably, T4 is a maximum of 710°C, preferably a maximum of 705°C, more preferably a maximum of 700°C, even more preferably a maximum of 695°C, most preferably a maximum of 690°C, and particularly a maximum of 685°C.

[0115] Preferably, p4 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and especially at least 22 bar a.

[0116] Preferably, p4 is a maximum of 80 bar a, preferably a maximum of 70 bar a, more preferably a maximum of 60 bar a, even more preferably a maximum of 50 bar a, most preferably a maximum of 40 bar a, and especially a maximum of 30 bar a.

[0117] Preferably, T4 > T3.

[0118] Preferably, the magnitude of the relative temperature difference |T3-T4| is at least 10°C, more preferably at least 15°C, even more preferably at least 20°C, most preferably at least 25°C, and particularly at least 30°C.

[0119] Preferably, the magnitude of the relative temperature difference |T3-T4| is at least 35°C, more preferably at least 40°C, even more preferably at least 45°C, most preferably at least 50°C, and especially at least 55°C.

[0120] Preferably, the magnitude of the relative temperature difference |T3-T4| is a maximum of 55°C, more preferably a maximum of 50°C, even more preferably a maximum of 45°C, most preferably a maximum of 40°C, and particularly a maximum of 35°C.

[0121] Preferably, the magnitude of the relative temperature difference |T3-T4| is a maximum of 30°C, more preferably a maximum of 25°C, even more preferably a maximum of 20°C, most preferably a maximum of 15°C, and especially a maximum of 10°C.

[0122] In a preferred embodiment, -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃, and -T4 is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃.

[0123] Preferably, p4 > p3.

[0124] Preferably, the magnitude of the relative pressure difference |p3-p4| is a maximum of 6 bar, preferably a maximum of 5 bar, more preferably a maximum of 4 bar, even more preferably a maximum of 3 bar, most preferably a maximum of 2 bar, and especially a maximum of 1 bar.

[0125] Preferably, the combustion gas is burned in at least one burner to produce at least one flame, thereby introducing thermal energy into the tube, and the thermal energy flow Q introduced into the tube w The length of the pipe is L R It moves forward in a non-constant manner over a certain distance.

[0126] Preferably, the thermal energy flow Qw The length of the pipe is L R It has the maximum value above.

[0127] Preferably, each tube is conceptually defined by its length L. R It can be divided into two equal halves above, and the intermediate product gas or product gas flows first through the first half, then through the second half, with thermal energy flow Q in the first half. w It reaches its maximum value.

[0128] Preferably, each tube is conceptually defined by its length L. R It can be divided into four equal segments above, and the intermediate product gas or product gas flows first through the first segment, then the second segment, finally the third segment, and then the fourth segment, with thermal energy flow Q in the second segment. w It reaches its maximum value.

[0129] The combustion gas is preferably burned in at least one burner to produce at least one flame, the length of which L F The length L of the pipe is in the direction of the flow of the combustion gases. R It extends essentially parallel to it.

[0130] Preferably, the combustion gases flow in essentially the same direction as the intermediate product gases or product gases (ceiling combustion).

[0131] Preferably, L R >L F That is the case.

[0132] Preferably, the length ratio L R :L F The ratio is within the range of 10:1 to 1.1:1, preferably 7:1 to 1.5:1, and more preferably 4:1 to 2:1.

[0133] Preferably, when the intermediate product gas or product gas flows through the pipe in step (h), the amount of heat consumed by the endothermic decomposition of NH3 is initially the amount of heat energy flow Q due to the combustion of the combustion gas.w As a result, the amount of heat introduced into the tube is greater than the amount of heat introduced into the tube, and the intermediate product gas or product gas first reaches the lowest gas temperature T while flowing through the tube. min It is cooled down to (T min <T3)。

[0134] Preferably, relative temperature difference |T3-T min The magnitude of | is at least 10°C, more preferably at least 20°C, even more preferably at least 30°C, most preferably at least 30°C, and especially at least 40°C.

[0135] Preferably, T min The temperature is in the range of 560 to 600°C, preferably 570 to 590°C.

[0136] Preferably, the lowest gas temperature T min Upon reaching this point, the amount of heat consumed by the endothermic decomposition of NH3 is subsequently converted into a thermal energy flow Q by the combustion of the combustion gases. w As a result, the amount of heat introduced into the tube becomes less than the amount of heat introduced into the tube, and consequently, the intermediate product gas or product gas is heated as it subsequently flows through the tube (T min <T4)。

[0137] Preferably, relative temperature difference |T4-T min The magnitude of | is at least 50°C, more preferably at least 55°C, even more preferably at least 60°C, most preferably at least 65°C, and particularly at least 70°C.

[0138] Preferably, each tube is conceptually defined by its length L. R It can be divided into two equal halves above, and the intermediate product gas or product gas flows first through the first half, then through the second half, with the lowest gas temperature T when flowing through the first half. m It reaches.

[0139] Preferably, each tube is conceptually defined by its length L. RThe gas can be divided into four equal segments, and the intermediate product gas or product gas flows first through the first segment, then the second segment, finally the third segment, and then the fourth segment, with the lowest gas temperature T being reached when flowing through the first segment. m It reaches.

[0140] In a preferred embodiment, -T1 is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃. -T2 is within the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, and most preferably 450±10℃. -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃, and -T4 is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃.

[0141] In another preferred embodiment, -T1 is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃. -T2 is within the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, and most preferably 350±10℃. -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃, and -T4 is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃.

[0142] Preferably, the combustion gas contains NH3, and preferably, the reaction gas supplied in step (a) is divided into (i) a first portion supplied to step (b) and (ii) a second portion that acts as a combustion gas.

[0143] Preferably, the second portion accounts for 8.0 mol% or less, preferably 7.5 mol% or less, more preferably 7.0 mol% or less, most preferably 6.5 mol% or less, and particularly 5 mol% or less of the reaction gas supplied in step (a).

[0144] This method preferably includes the following additional steps. (j) To obtain H2 enrichment product gas and H2 depletion off gas, the product gas is washed by pressure swing adsorption, preferably the H2 depletion off gas is recycled and introduced into the combustion gas.

[0145] A further aspect of the present invention relates to an apparatus for carrying out the above-described method of the present invention.

[0146] Preferred embodiments of the present invention are summarized below in paragraphs 1 to 103.

[0147] Text 1: A method for producing H2 from NH3, comprising: (a) supplying a reaction gas containing or essentially consisting of NH3; (b) heating the reaction gas to a gas temperature T1 in the range of 550 to 850°C at a pressure p1 of at least 10 bar a; (c) introducing the heated reaction gas into at least one fixed-bed reactor containing at least one catalyst bed containing or essentially consisting of an NH3 decomposition catalyst at gas temperature T1 and pressure p1; (d) partially decomposing NH3 in at least one fixed-bed reactor on at least one catalyst bed to obtain an intermediate product gas containing or essentially consisting of H2, N2 and undecomposed NH3; (e) discharging the intermediate product gas from at least one fixed-bed reactor at a gas temperature T2 in the range of 300 to 700°C and a pressure p2 of at least 10 bar a; (f) at least 10 bar A method comprising the steps of: (a) heating an intermediate product gas to a gas temperature T3 in the range of 550 to 700°C at a pressure p3; (g) introducing the heated intermediate product gas into at least one tubular reactor having a number of parallel tubes, each containing at least one catalyst bed, which is heated by combustion of a combustion gas and contains or essentially consists of a nickel-based NH3 decomposition catalyst, at gas temperature T3 and pressure p3; (h) decomposing NH3 on the catalyst bed in at least one tubular reactor to obtain a product gas containing or essentially consisting of H2, N2 and some undecomposed NH3; and (i) discharging the product gas from at least one tubular reactor at a gas temperature T4 in the range of 550 to 750°C and a pressure p4 of at least 10 bar a.

[0148] Text 2: The method according to Text 1, wherein at least one catalyst bed of the fixed-bed reactor is not heated.

[0149] Text 3: The method according to Text 1 or 2, wherein at least one fixed-bed reactor is operated adiabatically.

[0150] Text 4: The method according to any one of Texts 1 to 3, wherein the NH3 decomposition catalyst in at least one catalyst bed of a fixed-bed reactor is nickel-based, preferably supported nickel.

[0151] Text 5: A nickel-based NH3 decomposition catalyst in at least one catalyst bed of a fixed-bed reactor for NH3 decomposition, 240 kJ·mol -1 The following is preferably 230 kJ·mol -1 More preferably, 220 kJ·mol -1 More preferably, 210 kJ·mol -1 Below, the most preferred value is 200 kJ·mol. -1 The following, in particular, 190 kJ·mol -1 The method according to any one of sentences 1 to 4, wherein the (apparent) activation energy is as follows:

[0152] Text 6: A nickel-based NH3 decomposition catalyst for at least one catalyst bed of a fixed-bed reactor for NH3 decomposition, 180 kJ·mol -1 The following is preferably 170 kJ·mol -1 More preferably, 160 kJ·mol -1 More preferably, 150 kJ·mol -1 Below, the most preferred amount is 140 kJ·mol. -1 The following, in particular, 130 kJ·mol -1 The method according to any one of sentences 1 to 5, having the following (apparent) activation energy.

[0153] Text 7: The method according to any one of Texts 1 to 6, wherein at least one fixed-bed reactor comprises a first catalyst bed containing a first NH3 decomposition catalyst and a second catalyst bed containing a second NH3 decomposition catalyst, the second catalyst bed being located downstream of the first catalyst bed in the flow direction of the reaction gas or intermediate product gas.

[0154] Text 8: The method according to Text 7, wherein the first NH3 decomposition catalyst and the second NH3 decomposition catalyst are the same.

[0155] Text 9: The method according to Text 7, wherein the first NH3 decomposition catalyst and the second NH3 decomposition catalyst are different.

[0156] Text 10: The method according to Text 9, wherein the second NH3 decomposition catalyst has a higher (apparent) activation energy for the decomposition of NH3 than the first NH3 decomposition catalyst.

[0157] Text 11: The method according to any one of Texts 1 to 10, wherein at least one catalyst bed of a fixed-bed reactor essentially takes the form of a cylinder through which the reaction gas or intermediate product gas flows axially.

[0158] Text 12: The method according to any one of Texts 1 to 11, wherein at least one catalyst bed of a fixed-bed reactor essentially takes the form of a hollow cylinder through which the reaction gas or intermediate product gas flows radially.

[0159] Text 13: The method according to any one of Texts 1 to 12, wherein at least one catalyst bed of a fixed-bed reactor has an essentially circular cross-section having a diameter of at least 80 cm, preferably at least 100 cm, preferably at least 120 cm, more preferably at least 140 cm, most preferably at least 160 cm, and especially at least 180 cm.

[0160] Text 14: The method according to any one of Texts 1 to 13, wherein, in the flow direction of the reaction gas or intermediate product gas, at least one catalyst bed of a fixed-bed reactor has a length of at least 80 cm, preferably at least 100 cm, preferably at least 120 cm, more preferably at least 140 cm, most preferably at least 160 cm, and particularly at least 180 cm.

[0161] Text 15: At least one catalyst bed of a fixed-bed reactor has been used for 5,000 to 25,000 hours. -1 Preferably 10,000 to 20,000 hours -1 more preferably 12,500 to 17,500 hours -1 The method described in any of sentences 1 to 14, having a spatial velocity in the range of .

[0162] Text 16: The method according to any of Texts 1 to 15, wherein T1 is in the range of 550 to 700°C.

[0163] Sentence 17: The method according to any one of sentences 1 to 16, wherein T1 is at least 595°C, preferably at least 600°C, more preferably at least 605°C, even more preferably at least 610°C, most preferably at least 615°C, and particularly at least 620°C.

[0164] Sentence 18: The method according to any one of sentences 1 to 17, wherein T1 is at least 625°C, preferably at least 630°C, more preferably at least 635°C, even more preferably at least 640°C, most preferably at least 645°C, and particularly at least 650°C.

[0165] Sentence 19: The method according to any one of sentences 1 to 18, wherein T1 is a maximum of 710°C, preferably a maximum of 705°C, more preferably a maximum of 700°C, even more preferably a maximum of 695°C, most preferably a maximum of 690°C, and particularly a maximum of 685°C.

[0166] Sentence 20: The method according to any one of sentences 1 to 19, wherein T1 is a maximum of 680°C, preferably a maximum of 675°C, more preferably a maximum of 670°C, even more preferably a maximum of 665°C, most preferably a maximum of 660°C, and particularly a maximum of 655°C.

[0167] The method according to any one of sentences 1 to 20, wherein p1 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and particularly at least 22 bar a.

[0168] The method according to any one of sentences 1 to 21, wherein p1 is at most 80 bar a, preferably at most 70 bar a, more preferably at most 60 bar a, even more preferably at most 50 bar a, most preferably at most 40 bar a, and especially at most 30 bar a.

[0169] Text 23: The method according to any one of Texts 1 to 22, wherein T2 is in the range of 300 to 690°C.

[0170] Sentence 24: The method according to any one of sentences 1 to 23, wherein T2 is at least 300°C, preferably at least 310°C, more preferably at least 320°C, even more preferably at least 330°C, most preferably at least 340°C, and particularly at least 350°C.

[0171] Sentence 25: The method according to any one of sentences 1 to 24, wherein T2 is at least 400°C, preferably at least 410°C, more preferably at least 420°C, even more preferably at least 430°C, most preferably at least 440°C, and particularly at least 450°C.

[0172] Sentence 26: The method according to any one of sentences 1 to 25, wherein T2 is a maximum of 510°C, preferably a maximum of 500°C, more preferably a maximum of 490°C, even more preferably a maximum of 480°C, most preferably a maximum of 470°C, and particularly a maximum of 460°C.

[0173] Sentence 27: The method according to any one of sentences 1 to 26, wherein T2 is a maximum of 410°C, preferably a maximum of 400°C, more preferably a maximum of 390°C, even more preferably a maximum of 380°C, most preferably a maximum of 370°C, and particularly a maximum of 360°C.

[0174] The method according to any one of sentences 1 to 27, wherein p2 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and particularly at least 22 bar a.

[0175] The method according to any one of sentences 1 to 28, wherein p2 is at most 80 bar a, preferably at most 70 bar a, more preferably at most 60 bar a, even more preferably at most 50 bar a, most preferably at most 40 bar a, and especially at most at most 30 bar a.

[0176] Sentence 30: The method described in any of sentences 1 through 29, wherein T1 > T2.

[0177] Sentence 31: The method according to any one of sentences 1 to 30, wherein the magnitude of the relative temperature difference |T1-T2| is at least 50°C, more preferably at least 75°C, even more preferably at least 100°C, most preferably at least 125°C, and particularly at least 150°C.

[0178] Sentence 32: The method according to any one of sentences 1 to 31, wherein the magnitude of the relative temperature difference |T1-T2| is at least 175°C, more preferably at least 200°C, even more preferably at least 225°C, most preferably at least 250°C, and particularly at least 275°C.

[0179] The method according to any one of the statements in statement 33: -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, most preferably 650±10℃, and -T2 is in the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, most preferably 450±10℃.

[0180] The method according to any one of the statements in statement 34: -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, most preferably 650±10℃, and -T2 is in the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, most preferably 350±10℃.

[0181] The method described in any of sentences 1 through 34, wherein p1 > p2.

[0182] Sentence 36: The method according to any one of sentences 1 to 35, wherein the magnitude of the relative pressure difference |p1-p2| is a maximum of 6 bar, preferably a maximum of 5 bar, more preferably a maximum of 4 bar, even more preferably a maximum of 3 bar, most preferably a maximum of 2 bar, and especially a maximum of 1 bar.

[0183] Text 37: The method according to any one of Texts 1 to 36, wherein in step (d), the conversion rate of the decomposed NH3 is at least 12.5%, preferably at least 15%, more preferably at least 17.5%, even more preferably at least 20%, most preferably at least 22.5%, and particularly at least 25%, based on the amount of NH3 initially present in the reaction gas supplied in step (a) in each case.

[0184] The method according to any one of the documents 1 to 37, wherein the conversion rate of NH3 in step (d) is, in each case, up to 42.5%, preferably up to 40%, more preferably up to 37.5%, even more preferably up to 35%, most preferably up to 32.5%, and particularly up to 30%, based on the amount of NH3 initially present in the reaction gas supplied in step (a).

[0185] Sentence 39: The method described in any of sentences 1 to 38, wherein T3 > T2.

[0186] Sentence 40: The method according to any one of sentences 1 to 39, wherein the magnitude of the relative temperature difference |T3-T2| is at least 20°C, more preferably at least 40°C, even more preferably at least 60°C, most preferably at least 80°C, and particularly at least 100°C.

[0187] Sentence 41: The method according to any one of sentences 1 to 40, wherein the magnitude of the relative temperature difference |T3-T2| is at least 110°C, more preferably at least 120°C, even more preferably at least 130°C, most preferably at least 140°C, and particularly at least 150°C.

[0188] Document 42: - T2 is within the range of 450 ± 50 °C, preferably 450 ± 40 °C, more preferably 450 ± 30 °C, even more preferably 450 ± 20 °C, and most preferably 450 ± 10 °C, and - T3 is within the range of 620 ± 50 °C, preferably 620 ± 40 °C, more preferably 620 ± 30 °C, even more preferably 620 ± 20 °C, and most preferably 620 ± 10 °C, the method according to any one of Documents 1 to 41.

[0189] Document 43: - T2 is within the range of 350 ± 50 °C, preferably 350 ± 40 °C, more preferably 350 ± 30 °C, even more preferably 350 ± 20 °C, and most preferably 350 ± 10 °C, and - T3 is within the range of 620 ± 50 °C, preferably 620 ± 40 °C, more preferably 620 ± 30 °C, even more preferably 620 ± 20 °C, and most preferably 620 ± 10 °C, the method according to any one of Documents 1 to 41.

[0190] Document 44: p3 > p2, the method according to any one of Documents 1 to 43.

[0191] Document 45: The magnitude of the relative pressure difference |p3 - p2| is at most 6 bar, preferably at most 5 bar, more preferably at most 4 bar, even more preferably at most 3 bar, most preferably at most 2 bar, and particularly at most 1 bar, the method according to any one of Documents 1 to 44.

[0192] Document 46: T3 > T1, the method according to any one of Documents 1 to 45.

[0193] Document 47: T3 < T1, the method according to any one of Documents 1 to 46.

[0194] Document 48: The magnitude of the relative temperature difference |T1 - T3| is at least 5 °C, more preferably at least 10 °C, even more preferably at least 15 °C, most preferably at least 20 °C, and particularly at least 25 °C, the method according to any one of Documents 1 to 47.

[0195] Document 49: The method according to any one of Documents 1 to 48, wherein the magnitude of the relative temperature difference |T1 - T3| is at least 30°C, more preferably at least 35°C, even more preferably at least 40°C, most preferably at least 45°C, and particularly at least 50°C.

[0196] Document 50: The method according to any one of Documents 1 to 49, wherein the magnitude of the relative temperature difference |T1 - T3| is at most 50°C, more preferably at most 45°C, even more preferably at most 40°C, most preferably at most 35°C, and particularly at most 30°C.

[0197] Document 51: The method according to any one of Documents 1 to 50, wherein the magnitude of the relative temperature difference |T1 - T3| is at most 25°C, more preferably at most 20°C, even more preferably at most 15°C, most preferably at most 10°C, and particularly at most 5°C.

[0198] Document 52: The method according to any one of Documents 1 to 51, wherein -T1 is within the range of 650 ± 50°C, preferably 650 ± 40°C, more preferably 650 ± 30°C, even more preferably 650 ± 20°C, and most preferably 650 ± 10°C, and -T3 is within the range of 620 ± 50°C, preferably 620 ± 40°C, more preferably 620 ± 30°C, even more preferably 620 ± 20°C, and most preferably 620 ± 10°C.

[0199] Document 53: The method according to any one of Documents 1 to 52, wherein p3 < p1.

[0200] Document 54: The method according to any one of Documents 1 to 53, wherein the magnitude of the relative pressure difference |p3 - p1| is at most 6 bar, preferably at most 5 bar, more preferably at most 4 bar, even more preferably at most 3 bar, most preferably at most 2 bar, and particularly at most 1 bar.

[0201] Document 55: The method according to any one of Documents 1 to 54, wherein the nickel-based NH3 decomposition catalyst in at least one catalyst bed of a plurality of tubes of the tubular reactor is supported nickel.

[0202] Text 56: A nickel-based NH3 decomposition catalyst in at least one catalyst bed in each of the numerous tubes in a tubular reactor for NH3 decomposition, 240 kJ·mol -1 The following is preferably 230 kJ·mol -1 More preferably, 220 kJ·mol -1 More preferably, 210 kJ·mol -1 Below, the most preferred value is 200 kJ·mol. -1 The following, in particular, 190 kJ·mol -1 The method described in any of paragraphs 1 to 55, wherein the (apparent) activation energy is as follows:

[0203] Text 57: A nickel-based NH3 decomposition catalyst in at least one catalyst bed in each of the numerous tubes in a tubular reactor for NH3 decomposition, yielding 180 kJ·mol -1 The following is preferably 170 kJ·mol -1 More preferably, 160 kJ·mol -1 More preferably, 150 kJ·mol -1 Below, the most preferred amount is 140 kJ·mol. -1 The following, in particular, 130 kJ·mol -1 The method according to any one of sentences 1 to 56, wherein the (apparent) activation energy is as follows:

[0204] Text 58: The method according to any one of Texts 1 to 57, wherein the number of parallel tubes in the tubular reactor is at least 50, preferably at least 100, more preferably at least 150, even more preferably at least 200, most preferably at least 250, and particularly at least 300.

[0205] Text 59: Each of the numerous parallel tubes of the tubular reactor has a length L of at least 5.5 m, preferably at least 6.0 m, more preferably at least 6.5 m, even more preferably at least 8 m, most preferably at least 7.0 m, and especially at least 7.5 m in the flow direction of the intermediate product gas or product gas. R The method described in any of sentences 1 to 58, wherein the method is provided.

[0206] Document 60: The method according to any one of Documents 1 to 59, wherein a large number of parallel tubes of the tubular reactor have an essentially circular cross-section with an inner diameter of at least 5.0 cm, preferably at least 5.5 cm, more preferably at least 6.0 cm, even more preferably at least 6.5 cm, preferably at least 7.0 cm, particularly at least 7.5 cm in the flow direction of the intermediate product gas or the product gas.

[0207] Document 61: The method according to any one of Documents 1 to 60, wherein a large number of parallel tubes of the tubular reactor have an essentially circular cross-section with an inner diameter of at most 12 cm, preferably at most 11 cm, more preferably at most 10 cm, even more preferably at most 9.5 cm, most preferably at most 9.0 cm, particularly at most 8.5 cm in the flow direction of the intermediate product gas or the product gas.

[0208] Document 62: The method according to any one of Documents 1 to 61, wherein the catalyst bed of the tubular reactor as a whole has a space velocity in the range of 500 - 15000 h -1 , preferably 1000 - 10000 h -1 , more preferably 2500 - 7500 h -1 .

[0209] Document 63: The method according to any one of Documents 1 to 62, wherein at least one catalyst bed of the fixed-bed reactor has a larger space velocity as a whole than the catalyst bed of the tubular reactor.

[0210] Document 64: The method according to any one of Documents 1 to 63, wherein T3 is within the range of 560 - 700 °C.

[0211] Document 65: The method according to any one of Documents 1 to 64, wherein T3 is at least 590 °C, preferably at least 595 °C, more preferably at least 600 °C, even more preferably at least 605 °C, most preferably at least 610 °C, particularly at least 615 °C.

[0212] Sentence 66: The method according to any one of sentences 1 to 65, wherein T3 is a maximum of 650°C, preferably a maximum of 645°C, more preferably a maximum of 640°C, even more preferably a maximum of 635°C, most preferably a maximum of 630°C, and particularly a maximum of 625°C.

[0213] The method according to any of sentences 1 to 66, wherein p3 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and particularly at least 22 bar a.

[0214] The method according to any one of sentences 1 to 67, wherein p3 is at most 80 bar a, preferably at most 70 bar a, more preferably at most 60 bar a, even more preferably at most 50 bar a, most preferably at most 40 bar a, and especially at most 30 bar a.

[0215] Text 69: The method according to any one of Texts 1 to 68, wherein T4 is in the range of 560 to 750°C.

[0216] The method according to any one of the documents 1 to 69, wherein T4 is at least 650°C, preferably at least 655°C, more preferably at least 660°C, even more preferably at least 665°C, most preferably at least 670°C, and particularly at least 675°C.

[0217] Sentence 71: The method according to any one of sentences 1 to 70, wherein T4 is a maximum of 710°C, preferably a maximum of 705°C, more preferably a maximum of 700°C, even more preferably a maximum of 695°C, most preferably a maximum of 690°C, and particularly a maximum of 685°C.

[0218] The method according to any of sentences 1 to 71, wherein p4 is at least 12 bar a, preferably at least 14 bar a, more preferably at least 16 bar a, even more preferably at least 18 bar a, most preferably at least 20 bar a, and particularly at least 22 bar a.

[0219] The method according to any one of sentences 1 to 72, wherein sentence 73:p4 is at most 80 bar a, preferably at most 70 bar a, more preferably at most 60 bar a, even more preferably at most 50 bar a, most preferably at most 40 bar a, and especially at most 30 bar a.

[0220] The method described in any of sentences 1 to 73, wherein sentence 74: T4 > T3.

[0221] Sentence 75: The method according to any one of sentences 1 to 74, wherein the magnitude of the relative temperature difference |T3-T4| is at least 10°C, more preferably at least 15°C, even more preferably at least 20°C, most preferably at least 25°C, and particularly at least 30°C.

[0222] Sentence 76: The method according to any one of sentences 1 to 75, wherein the magnitude of the relative temperature difference |T3-T4| is at least 35°C, more preferably at least 40°C, even more preferably at least 45°C, most preferably at least 50°C, and particularly at least 55°C.

[0223] Text 77: The method according to any one of Texts 1 to 76, wherein the magnitude of the relative temperature difference |T3-T4| is at most 55°C, more preferably at most 50°C, even more preferably at most 45°C, most preferably at most 40°C, and particularly at most 35°C.

[0224] Text 78: The method according to any one of Texts 1 to 77, wherein the magnitude of the relative temperature difference |T3-T4| is at most 30°C, more preferably at most 25°C, even more preferably at most 20°C, most preferably at most 15°C, and particularly at most 10°C.

[0225] The method according to any one of Documents 1 to 78, wherein -T3 is within the range of 620 ± 50 °C, preferably 620 ± 40 °C, more preferably 620 ± 30 °C, even more preferably 620 ± 20 °C, and most preferably 620 ± 10 °C, and -T4 is within the range of 650 ± 50 °C, preferably 650 ± 40 °C, more preferably 650 ± 30 °C, even more preferably 650 ± 20 °C, and most preferably 650 ± 10 °C.

[0226] The method according to any one of Documents 1 to 79, wherein p4 > p3.

[0227] The method according to any one of Documents 1 to 80, wherein the magnitude of the relative pressure difference |p3 - p4| is at most 6 bar, preferably at most 5 bar, more preferably at most 4 bar, even more preferably at most 3 bar, most preferably at most 2 bar, and particularly at most 1 bar.

[0228] The method according to any one of Documents 1 to 81, wherein in step (h), the conversion rate of the decomposed NH3 is at least 90%, preferably at least 92.5%, more preferably at least 95%, even more preferably at least 96%, most preferably at least 97%, and particularly at least 98% based on the amount of NH3 initially present in the reaction gas supplied in step (a) in each case.

[0229] The method according to any one of Documents 1 to 82, wherein the combustion gas is burned with at least one burner to generate at least one flame, whereby thermal energy is introduced into the tube, and the thermal energy flow Q w advances non-steadily over the length L R of the tube.

[0230] The thermal energy flow Q w has a maximum value over the length L R of the tube, according to the method of Document 83.

[0231] Each tube is conceptually divided into segments along its length L RIt can be divided into two equal halves above, and the intermediate product gas or product gas first flows through the first half and then through the second half, and the heat energy flow Q in the first half w reaches its maximum value, according to the method described in sentence 84.

[0232] Sentence 86: Each tube can be conceptually divided into four equal segments on its length L R above, and the intermediate product gas or product gas first flows through the first segment, then through the second segment, then through the third segment, and finally through the fourth segment, and the heat energy flow Q in the second segment w reaches its maximum value, according to the method described in sentence 83 or 84.

[0233] Sentence 87: The combustion gas is burned by at least one burner to generate at least one flame, and its length L F extends essentially parallel to the length L of the tube in the flow direction of the burning combustion gas R according to the method described in any one of sentences 1 to 86.

[0234] Sentence 88: The burning combustion gas flows essentially in the same direction as the intermediate product gas or product gas (ceiling combustion), according to the method described in any one of sentences 1 to 87.

[0235] Sentence 89: L R >L F according to the method described in sentence 87 or 88.

[0236] Sentence 90: The length ratio L R :L F is within the range of 10:1 to 1.1:1, preferably 7:1 to 1.5:1, more preferably 4:1 to 2:1, according to the method described in any one of sentences 87 to 89.

[0237] Sentence 91: When the intermediate product gas or product gas flows through the tube in step (h), the amount of heat consumed by the endothermic decomposition of NH3 is initially the heat energy flow Q by the combustion of the combustion gas wgreater than the amount of heat introduced into the tube, so that the intermediate product gas or product gas is first cooled to a minimum gas temperature T min before flowing through the tube (T min < T3), the method according to any one of Clauses 1 to 90.

[0238] Clause 92: The magnitude of the relative temperature difference |T3 - T min | is at least 10 °C, more preferably at least 20 °C, even more preferably at least 30 °C, most preferably at least 30 °C, especially at least 40 °C, the method according to Clause 91.

[0239] Clause 93: T min is in the range of 560 to 600 °C, preferably 570 to 590 °C, the method according to Clause 91 or 92.

[0240] Clause 94: When the minimum gas temperature T min is reached, the amount of heat consumed by the endothermic decomposition of NH3 becomes smaller than the amount of heat energy flow Q w introduced into the tube as a result, so that the intermediate product gas or product gas is then heated when flowing through the tube (T min < T4), the method according to any one of Clauses 91 to 93.

[0241] Clause 95: The magnitude of the relative temperature difference |T4 - T min | is at least 50 °C, more preferably at least 55 °C, even more preferably at least 60 °C, most preferably at least 65 °C, especially at least 70 °C, the method according to Clause 94.

[0242] Clause 96: Each tube can be conceptually divided into two equal halves along its length L R such that the intermediate product gas or product gas first flows through the first half and then through the second half, and reaches the minimum gas temperature T m when flowing through the first half, the method according to any one of Clauses 91 to 95.

[0243] Text 97: Each pipe is conceptually defined by its length L. R The gas can be divided into four equal segments, and the intermediate product gas or product gas flows through the first segment first, then the second segment, finally the third segment, and then the fourth segment, with the lowest gas temperature T when flowing through the first segment. m The method described in any of sentences 91 to 96, which reaches the desired outcome.

[0244] The method according to any one of the statements in statement 98: -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃; -T2 is in the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, and most preferably 450±10℃; -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, and most preferably 620±10℃; and -T4 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃.

[0245] The method according to any one of the statements in statement 99: -T1 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, most preferably 650±10℃, -T2 is in the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, most preferably 350±10℃, -T3 is in the range of 620±50℃, preferably 620±40℃, more preferably 620±30℃, even more preferably 620±20℃, most preferably 620±10℃, and -T4 is in the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, most preferably 650±10℃.

[0246] Paragraph 100: The method according to any one of paragraphs 1 to 99, wherein the combustion gas contains NH3, and preferably, the reaction gas supplied in step (a) is divided into (i) a first portion supplied to step (b) and (ii) a second portion that acts as the combustion gas.

[0247] Paragraph 101: The method according to paragraph 96, wherein the second portion accounts for 8.0 mol% or less, more preferably 7.5 mol% or less, even more preferably 7.0 mol% or less, most preferably 6.5 mol% or less, and particularly 5 mol% or less of the reaction gas supplied in step (a).

[0248] Paragraph 102: The method according to any one of paragraphs 1 to 101, including an additional step of (j) cleaning the product gas by pressure swing adsorption to obtain a H2-enriched product gas and a H2-depleted off-gas, and preferably, the H2-depleted off-gas is recycled and introduced into the combustion gas.

[0249] Paragraph 103: An apparatus for implementing the method according to any one of paragraphs 1 to 102. BRIEF DESCRIPTION OF THE DRAWINGS

[0250] [Figure 1] A schematic diagram of a preferred embodiment in which the flow of the intermediate product gas is introduced into the tubular reactor from top to bottom is shown. [Figure 2] A schematic diagram of the change in gas temperature in the chemical reaction of the intermediate product gas to obtain the product gas on the nickel-based NH3 decomposition catalyst is shown. [Figure 3] A schematic diagram of the change in gas temperature in the chemical reaction of the intermediate product gas to obtain the product gas on the nickel-based NH3 decomposition catalyst as a function of the length LR of the tubular reactor is shown. DETAILED DESCRIPTION OF THE INVENTION

[0251] Preferred embodiments of the method of the present invention are shown in FIGS. 1 to 3.

[0252] Figure 1 shows a schematic diagram of a preferred embodiment in which the flow of intermediate product gas 2 is introduced into the tubular reactor 1 from top to bottom. The tubular reactor 1 contains a nickel-based NH3 decomposition catalyst 3. The flow of combustion gas 4 is guided to combustion chambers 5a and 5b, where it burns, forming flames 6a and 6b in the direction of the burning combustion gas flow. The tubular reactor 1 has a length L R It has the length of flames 6a and 6b respectively L F The heat generated by the combustion of combustion gas 4 heats the tubular reactor 1. The flow of product gas 7 obtained by catalytic decomposition is discharged from the tubular reactor 1. The combustion off gas 8 obtained by the combustion of combustion gas 7 is discharged from the combustion chambers 5a and 5b.

[0253] Figure 2 shows a schematic diagram of the change in gas temperature during the chemical reaction of intermediate product gases to obtain product gases on a nickel-based NH3 decomposition catalyst. Two reaction methods, A (dashed line) and B (solid line), are distinguished, and they differ in the gas temperature T3 when the gas is introduced into the reactor, i.e., when it first comes into contact with the NH3 decomposition catalyst. In reaction method A, the gas temperature T 3A The temperature is relatively high. Since the decomposition of NH3 is endothermic, the reaction is promoted by a relatively high temperature and proceeds rapidly, resulting in a clear decrease in the gas temperature initially as a result of the heat consumed, and then the gas temperature can rise again downstream as a result of heating the reactor. Finally, the product gas is produced at the maximum decomposition yield, at a gas temperature T 4A The gas exits the reactor. The gas temperature passes its minimum value over the distance within the reactor, which also means that the rate of the decomposition reaction passes its minimum value. In this reaction scheme, the rate of the decomposition reaction is initially very fast (to the left of the minimum), but also relatively slow as a result of the associated distinct temperature decrease (to the right of the minimum). In such a reaction scheme, a relatively large amount of nickel-based NH3 decomposition catalyst is required to produce a high yield. In reaction scheme B, the gas temperature T 3B The initial reaction rate is relatively low. In this case, the rate of the decomposition reaction is not very fast at first, but the gas temperature also does not drop very much. In this reaction scheme, the downstream gas temperature can rise again to a higher temperature relatively quickly as a result of heating the reactor.

[0254] Figure 3 shows the length L of the tubular reactor. R A schematic diagram of the change in gas temperature in the chemical reaction of intermediate product gases to obtain product gases on a nickel-based NH3 decomposition catalyst is shown as a function of L. In reaction method A, the length of the tubular reactor L RA The reaction time is relatively short, and the product gas is produced at a relatively low gas temperature T. 4A And the decomposed NH3 exits the pipe reactor with a relatively low conversion rate. In reaction method B, the length of the tubular reactor L RA The duration is relatively long, and the product gas is produced at a relatively high gas temperature T. 4B The decomposed NH3 exits the pipe reactor with a relatively high conversion rate. [Explanation of Symbols]

[0255] 1. Tubular reactor 2. Intermediate product gas 3. Nickel-based NH3 decomposition catalyst 4. Combustion gases 5a / 5b Combustion Chamber 6a / 6b flame 7. Product Gases 8. Combustion off-gas

Claims

1. NH ３ From H ２ A method for generating, (a) NH ３ Includes or NH ３ To supply the reaction gas that is essentially derived from, (b) pressure p at least 10 bar a １ gas temperature T in the range of 550 to 850°C １ Heat the reaction gas, (c) introducing the heated reaction gas into at least one fixed bed reactor comprising at least one catalyst bed containing an NH １ decomposition catalyst or consisting essentially of an NH １ decomposition catalyst, at a gas temperature T ３ and a pressure p ３ ; (d) On the at least one catalyst bed, in the at least one fixed-bed reactor, NH ３ Partially decompose H ２ , N ２ and undegraded NH ３ Includes or H ２ , N ２ and undegraded NH ３ To obtain an essential intermediate product gas from, (e) Gas temperature T in the range of 300 to 700°C ２ and a pressure p of at least 10 bar a ２ The intermediate product gas is discharged from at least one of the fixed-bed reactors. (f) pressure p at least 10 bar a ３ Gas temperature T in the range of 550-700°C ３ To heat the intermediate product gas, (g) The heated intermediate product gas is heated to a gas temperature T ３ and pressure p ３ Then, it is heated by the combustion of the combustion gas, and nickel-based NH ３ Contains a decomposition catalyst or nickel-based NH ３ To introduce at least one tubular reactor having a number of parallel tubes, each containing at least one catalyst bed essentially composed of a decomposition catalyst, (h) On the catalyst bed, in the at least one tubular reactor, NH ３ Decompose H ２ , N ２ and some undegraded NH ３ Includes or H ２ , N ２ and some undegraded NH ３ To obtain a product gas that is essentially derived from, and (i) Gas temperature T in the range of 550 to 750°C ４ and a pressure p of at least 10 bar a ４ The product gas is discharged from at least one of the tubular reactors. A method including the above steps.

2. T ４ >T ３ The method according to claim 1.

3. The method according to either claim 1 or 2, wherein the at least one fixed-bed reactor is operated adiabatically.

4. The NH of the at least one catalyst bed of the fixed bed reactor ３ The method according to any one of claims 1 to 3, wherein the decomposition catalyst is nickel-based, preferably supported nickel.

5. -T １ However, the temperature is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃, and -T ２ However, the temperature is within the range of 450±50℃, preferably 450±40℃, more preferably 450±30℃, even more preferably 450±20℃, and most preferably 450±10℃. The process according to any one of claims 1 to 4.

6. -T １ However, the temperature is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃, and -T ２ However, the temperature is within the range of 350±50℃, preferably 350±40℃, more preferably 350±30℃, even more preferably 350±20℃, and most preferably 350±10℃. The method according to any one of claims 1 to 4.

7. In step (d), the decomposed NH ３ The conversion rate of is, in each case, the NH that is initially present in the reaction gas supplied in step (a). ３ The method according to any one of claims 1 to 6, wherein the amount is at least 12.5%, preferably at least 15%, more preferably at least 17.5%, even more preferably at least 20%, most preferably at least 22.5%, and particularly at least 25%.

8. Each of the numerous parallel tubes in the tubular reactor has a length L of at least 5.5 m, preferably at least 6.0 m, more preferably at least 6.5 m, even more preferably at least 8 m, most preferably at least 7.0 m, and especially at least 7.5 m in the flow direction of the intermediate product gas or the product gas. Ｒ The method according to any one of claims 1 to 7, comprising:

9. -T ３ However, the temperature is within the range of 620±50°C, preferably 620±40°C, more preferably 620±30°C, even more preferably 620±20°C, and most preferably 620±10°C. -T ４ However, the temperature is within the range of 650±50℃, preferably 650±40℃, more preferably 650±30℃, even more preferably 650±20℃, and most preferably 650±10℃. The process according to any one of claims 1 to 8.

10. In step (h), the decomposed NH ３ The conversion rate of is, in each case, the NH that is initially present in the reaction gas supplied in step (a). ３ The method according to any one of claims 1 to 9, wherein the amount is at least 90%, preferably at least 92.5%, more preferably at least 95%, even more preferably at least 96%, most preferably at least 97%, and particularly at least 98%.

11. The combustion gas is burned in at least one burner to produce at least one flame, the length of which L Ｆ However, in the direction of the flow of the combustion gas, the length L of the pipe Ｒ The method according to any one of claims 1 to 10, which extends essentially parallel to the same.

12. Length ratio L Ｒ : L Ｆ The method according to claim 11, wherein the ratio is in the range of 10:1 to 1.1:1, preferably 7:1 to 1.5:1, and more preferably 4:1 to 2:

1.

13. When the intermediate product gas or product gas flows through the pipe in step (h), NH ３ The amount of heat consumed by the endothermic decomposition is initially the thermal energy flow Q from the combustion of the combustion gas. ｗ The amount of heat introduced into the tube is greater than the amount of heat introduced into the tube, and as a result, the intermediate product gas or the product gas first reaches the lowest gas temperature T while flowing through the tube. ｍｉｎ It is cooled down to (T ｍｉｎ <T ３ ), the method according to any one of claims 1 to 12.

14. The minimum gas temperature T ｍｉｎ When you reach NH ３ The amount of heat consumed by the endothermic decomposition of the combustion gas is then used to create a thermal energy flow Q from the combustion of the combustion gas. ｗ As a result, the amount of heat introduced into the tube becomes smaller, and the intermediate product gas or the product gas is heated as it subsequently flows through the tube (T ｍｉｎ <T ４ ), the method according to claim 13.

15. Each of the aforementioned pipes is conceptually defined by its length L. Ｒ The gas can be divided into two equal halves, and the intermediate product gas or the product gas flows first through the first half, then through the second half, and the lowest gas temperature T is reached when the gas flows through the first half. ｍ The method according to claim 13 or 14, which reaches the desired outcome.

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