Process for recovery of h2

Abstract

The present invention relates to a method for recovering H2 from the conversion of NH3 in a plant, comprising one or more treatment stages, and to a plant for use in these methods.

Description

[0001] The present invention relates to processes for recovering H2 from the conversion of NH3 in plants and to plants for use in these processes.

[0002] Hydrogen is a promising energy carrier, but its storage and transportation are difficult. Ammonia has been proposed as an intermediate energy carrier because, under the right conditions, it can be converted into hydrogen with nitrogen as the only byproduct. Given this, the use of ammonia as a hydrogen intermediate has received more attention from both the public and private sectors given its potential to reduce carbon emissions.

[0003] The problem that uses hydrogen on an industrial scale causes is that, due to the physical and chemical problems presented by hydrogen, both the compressor and vacuum for safe industrial hydrogen applications require high capital investment, increased maintenance and very large energy consumption. However, many industrial-scale applications for hydrogen require higher pressures. Therefore, the object of the present invention is to provide an apparatus and method for converting and purifying hydrogen by ammonia under industrially usable pressures, while avoiding compressors or vacuum pumps in streams or feeds containing hydrogen. A related object is to drive the conversion of ammonia to hydrogen to nearly complete conversion by removing the hydrogen product from the equilibrium mixture without using a compressor or vacuum in streams and feeds containing hydrogen.

[0004] Cechetto et al., "H2production via ammonia decomposition in a catalytic membrane reactor", Fuel Processing Technology (2021), 106772, proposed a membrane reactor design featuring a Pd-based membrane reactor on a Ru-based catalyst. The membrane reactor demonstrated excellent recovery and conversion from a temperature of 425°C, but compared to systems where no vacuum is applied, vacuum pressure is required on the permeate side to drive conversion and recovery for optimal results. In addition, the article studies pressures of 6 bar and below at low volume flow rates, which are not useful for industrial applications.

[0005] Yun et al., "correlations of in palladium membranes for hydrogen separation," J. Membrane Sci. (2011) 28-45, review many of the useful features, properties, and limitations of Pd membranes, focusing on the fabrication of Pd membranes.

[0006] Schüth et al., “Ammonia as a possible element in an energy infrastructure: catalysts for ammonia decomposition,” Energy Eviron. Sci. 2012, p. 6278, reviewed various catalyst systems for converting ammonia to hydrogen and nitrogen. Similarly, Lamb et al., “Ammonia for hydrogen storage; A review of catalytic ammonia decomposition and hydrogen separation and purification,” Int. J. of hydrogen energy, 44 (2019) 3580, reviewed advances in catalysts for ammonia decomposition and hydrogen recovery.

[0007] Abashar, “Ultra-clean hydrogen production by ammonia Decomposition”, J. King Saud University-Engineering Sciences (2018), pp. 2-11, discloses a simulation mathematical model in which a single fixed bed reactor is compared with a single fixed bed membrane reactor and the superiority of the latter is shown. The journal article considered a multi-bed design in preliminary studies, however, no information on the reactor / membrane design is provided other than a mathematical description of the diffusion model, and the membrane is considered to be completely selective for hydrogen.

[0008] Therefore, it is necessary to recover hydrogen from the converted ammonia at high pressure and high purity on an industrial scale, preferably without using a compressor or vacuum for the hydrogen-containing stream. It is also necessary to deliver purified hydrogen while maximizing ammonia conversion at high pressure while avoiding a compressor or vacuum for the hydrogen-containing stream. The purpose of both of these requirements is to provide an industrially processable hydrogen source that can be used for chemical transformations requiring high pressure, or for an energy source under the most cost-effective, environmentally friendly and safe conditions possible.

[0009] The present invention therefore relates to a method and apparatus for recovering hydrogen from converted ammonia at high pressure and high purity without the use of a compressor or vacuum. These objects are achieved by a design comprising one zone or n zones connected in series, wherein, in each zone, a conversion reactor converts ammonia into hydrogen and nitrogen at elevated temperature and pressure, and the resulting gas stream comprising hydrogen, nitrogen and ammonia is fed to two separate membrane purification units connected in series. The n zones connected in series can be connected together in series to drive the conversion of ammonia to near completion while providing high pressure hydrogen with excellent purity while completely avoiding the use of a compressor or vacuum for the hydrogen stream.

[0010] The invention therefore relates to a process for recovering H2 from the conversion of NH3 in a plant comprising n zones Z(i) connected in series, where i=1 ... n, where n≥2,

[0011] Each zone Z(i) includes

[0012] a conversion reactor CR(i) comprising a catalyst C(i) for converting NH3 to give H2,

[0013] - the first membrane unit M1(i) and

[0014] - a second membrane unit M2(i),

[0015] wherein in Z(i), CR(i) is located upstream of M1(i) and M2(i) is located downstream of M1(i), wherein Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0016] The method includes

[0017] (a) providing a feed gas stream FS(0) comprising NH3;

[0018] (b) n consecutive processing stages S(i), i=1…n,

[0019] Among them, in each S(i), S(i) includes

[0020] The conversion phase SA(i) includes

[0021] - feeding a gas stream FS(i-1) into a conversion reactor CR(i) included in Z(i) and contacting said stream FS(i-1) with C(i) in CR(i) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(i) having a molar ratio n(H2):n(NH3)=x(G(i));

[0022] - removing the gas stream G(i) comprising NH3, N2 and H2 from CR(i);

[0023] - passing this gas stream G(i) as feed gas stream F1(i) through a separation stage SB(i), F1(i) having the same chemical composition as G(i) and the molar ratio x(G(i))=x(F1(i));

[0024] The separation stage SB(i) comprises

[0025] -In pressure ratio passing the feed gas stream F1(i) through a first membrane unit M1(i) comprising at least one membrane of Z(i),

[0026] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0027] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(i)) at constant temperature, is greater than 1, obtaining

[0028] ■ a permeate gas stream P1(i) comprising H2; and

[0029] ■ A retentate gas stream R1(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(i)); x(R1(i)) <x(F1(i));

[0030] - passing the retentate gas stream R1(i) through a separation stage SC(i) as feed gas stream F2(i), F2(i) having the same chemical and physical composition and molar ratio x(R1(i))=x(F2(i)) as R1(i);

[0031] The separation stage SC(i) comprises

[0032] -In pressure ratio passing the feed gas stream F2(i) through a second membrane unit M2(i) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000,

[0033] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at constant temperature, is greater than 1, obtaining

[0034] o a permeate gas stream P2(i) comprising H2; and

[0035] o A retentate gas stream R2(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(i)); x(R2(i)) <x(F2(i));

[0036] - removing the gas stream R2(i) from Z(i);

[0037] wherein, when i=1 ... n-1, the gas stream R2(i) is removed from Z(i) as a feed stream FS(i), FS(i) having the same chemical and physical composition and molar ratio x(R2(i))=x(FS(i)) as R2(i); and

[0038] wherein, when i=n, ​​the gas stream R2(n) is removed from Z(i) as a product gas stream;

[0039] The volume flow ratio of FS(i-1) to FS(i) is in the range of 1.05:1 to 4:1.

[0040] Preferably, n=2 to 10, more preferably n=2 to 5, more preferably n=2, 3 or 4, more preferably n=2 or 3.

[0041] Preferably, according to stage S(i), no vacuum device or compressor is operated downstream of the conversion reactor CR(i) according to SA(i) when obtaining the permeate gas stream and / or the retentate gas stream, preferably when obtaining any permeate gas stream and / or any retentate gas;

[0042] More preferably, according to all stages S(i) of the process, the stream or feed comprising hydrogen in the process is not compressed by a compressor or evacuated by a vacuum pump.

[0043] Preferably, the present invention relates to a process for recovering H2 from the conversion of NH3 in a plant comprising n zones Z(i) connected in series, wherein i=1 ... n, wherein n≥2, more preferably n=2 to 10, more preferably n=2 to 5, more preferably n=2, 3 or 4, more preferably n=2 or 3,

[0044] Each zone Z(i) includes

[0045] a conversion reactor CR(i) comprising a catalyst C(i) for converting NH3 to give H2,

[0046] - the first membrane unit M1(i) and

[0047] - a second membrane unit M2(i),

[0048] wherein in Z(i), CR(i) is located upstream of M1(i) and M2(i) is located downstream of M1(i), wherein Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0049] The method includes

[0050] (a) providing a feed gas stream FS(0) comprising NH3;

[0051] (b) n consecutive processing stages S(i), i=1…n,

[0052] Among them, in each S(i), S(i) includes

[0053] The conversion phase SA(i) includes

[0054] - feeding a gas stream FS(i-1) into a conversion reactor CR(i) included in Z(i) and contacting said stream FS(i-1) with C(i) in CR(i) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(i) having a molar ratio n(H2):n(NH3)=x(G(i));

[0055] - removing the gas stream G(i) comprising NH3, N2 and H2 from CR(i);

[0056] - passing this gas stream G(i) as feed gas stream F1(i) through a separation stage SB(i), F1(i) having the same chemical composition as G(i) and the molar ratio x(G(i))=x(F1(i));

[0057] The separation stage SB(i) comprises

[0058] - passing the feed gas stream F1(i) through a first membrane unit M1(i) comprising at least one membrane of Z(i) at a pressure ratio φ,

[0059] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0060] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(i)) at constant temperature, is greater than 1, obtaining

[0061] ■ a permeate gas stream P1(i) comprising H2; and

[0062] ■ A retentate gas stream R1(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(i)); x(R1(i)) <x(F1(i));

[0063] - passing the retentate gas stream R1(i) through a separation stage SC(i) as feed gas stream F2(i), F2(i) having the same chemical and physical composition and molar ratio x(R1(i))=x(F2(i)) as R1(i);

[0064] The separation stage SC(i) comprises

[0065] - passing the feed gas stream F2(i) through a second membrane unit M2(i) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0066] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at constant temperature, is greater than 1, obtaining

[0067] o a permeate gas stream P2(i) comprising H2; and

[0068] o A retentate gas stream R2(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(i)); x(R2(i)) <x(F2(i));

[0069] - removing the gas stream R2(i) from Z(i);

[0070] wherein, when i=1 ... n-1, the gas stream R2(i) is removed from Z(i) as a feed stream FS(i), FS(i) having the same chemical and physical composition and molar ratio x(R2(i))=x(FS(i)) as R2(i); and

[0071] wherein, when i=n, ​​the gas stream R2(n) is removed from Z(i) as a product gas stream;

[0072] wherein the volume flow ratio of FS(i-1) to FS(i) is in the range of 1.05:1 to 4:1;

[0073] wherein, more preferably, according to stage S(i), no vacuum device or compressor is operated downstream of the conversion reactor CR(i) according to SA(i) when obtaining the permeate gas stream and / or the retentate gas stream, more preferably when obtaining any permeate gas stream and / or any retentate gas;

[0074] More preferably, according to all stages S(i) of the process, the stream or feed comprising hydrogen in the process is not compressed by a compressor or evacuated by a vacuum pump.

[0075] Preferably, none of the n continuous processing stages S(i) comprises the use of an ammonia condenser and / or the use of a gas-liquid phase separator, more preferably none of the n continuous processing stages S(i) comprises the use of an ammonia condenser and none of the n continuous processing stages S(i) comprises the use of a gas-liquid phase separator.

[0076] Preferably, the present invention relates to a process for recovering H2 from the conversion of NH3 in a plant comprising n zones Z(i) connected in series, wherein i=1 ... n, wherein n≥2, more preferably n=2 to 10, more preferably n=2 to 5, more preferably n=2, 3 or 4, more preferably n=2 or 3,

[0077] Each zone Z(i) includes

[0078] a conversion reactor CR(i) comprising a catalyst C(i) for converting NH3 to give H2,

[0079] - the first membrane unit M1(i) and

[0080] - a second membrane unit M2(i),

[0081] wherein in Z(i), CR(i) is located upstream of M1(i) and M2(i) is located downstream of M1(i), wherein Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0082] The method includes

[0083] (a) providing a feed gas stream FS(0) comprising NH3;

[0084] (b) n consecutive processing stages S(i), i=1…n,

[0085] Among them, in each S(i), S(i) includes

[0086] The conversion phase SA(i) includes

[0087] - feeding a gas stream FS(i-1) into a conversion reactor CR(i) included in Z(i) and contacting said stream FS(i-1) with C(i) in CR(i) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(i) having a molar ratio n(H2):n(NH3)=x(G(i));

[0088] - removing the gas stream G(i) comprising NH3, N2 and H2 from CR(i);

[0089] - passing this gas stream G(i) as feed gas stream F1(i) through a separation stage SB(i), F1(i) having the same chemical composition as G(i) and the molar ratio x(G(i))=x(F1(i));

[0090] The separation stage SB(i) comprises

[0091] - passing the feed gas stream F1(i) through a first membrane unit M1(i) comprising at least one membrane of Z(i) at a pressure ratio φ,

[0092] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0093] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(i)) at constant temperature, is greater than 1, obtaining

[0094] ■ a permeate gas stream P1(i) comprising H2; and

[0095] ■ A retentate gas stream R1(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(i)); x(R1(i)) <x(F1(i));

[0096] - passing the retentate gas stream R1(i) through a separation stage SC(i) as feed gas stream F2(i), F2(i) having the same chemical and physical composition and molar ratio x(R1(i))=x(F2(i)) as R1(i);

[0097] The separation stage SC(i) comprises

[0098] - passing the feed gas stream F2(i) through a second membrane unit M2(i) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0099] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at constant temperature, is greater than 1, obtaining

[0100] o a permeate gas stream P2(i) comprising H2; and

[0101] o A retentate gas stream R2(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(i)); x(R2(i)) <x(F2(i));

[0102] - removing the gas stream R2(i) from Z(i);

[0103] wherein, when i=1 ... n-1, the gas stream R2(i) is removed from Z(i) as a feed stream FS(i), FS(i) having the same chemical and physical composition and molar ratio x(R2(i))=x(FS(i)) as R2(i); and

[0104] wherein, when i=n, ​​the gas stream R2(n) is removed from Z(i) as a product gas stream;

[0105] wherein the volume flow ratio of FS(i-1) to FS(i) is in the range of 1.05:1 to 4:1;

[0106] Among them, it is more preferred that none of the n continuous processing stages S(i) include the use of an ammonia condenser and / or the use of a gas-liquid phase separator, and it is more preferred that none of the n continuous processing stages S(i) include the use of an ammonia condenser and none of the n continuous processing stages S(i) include the use of a gas-liquid phase separator.

[0107] Preferably, the feed gas stream FS(0) comprises, preferably consists of, NH3 having a purity in the range of 85 to 99.99998 wt.-%, more preferably in the range of 95 to 99.998 wt.-%, more preferably in the range of 98 to 99.8 wt.-%, calculated based on the sum of all gas components present. In addition to NH3, the feed gas stream FS(0) may also preferably comprise impurities, wherein the impurities are more preferably one or more of N2, O2, water, CO2, CO, CH4, H2, hydrocarbons and Ar, more preferably one or more of N2, O2 and water, more preferably one or more of N2 and water.

[0108] Preferably, the feed gas stream FS(0) is obtained by a process selected from the group consisting of: the Haber-Bosch process, an electrochemical ammonia synthesis process, a non-thermal or thermal plasma-assisted ammonia production process and a combination of two or more thereof, more preferably obtained by the Haber-Bosch process or an electrochemical ammonia synthesis process.

[0109] In the context of the present invention, it is envisaged that an evaporation device can be used to provide the feed gas stream FS(0). In practice, the evaporation device will be used to evaporate a liquid NH3 source to obtain FS(0). Therefore, the evaporation device will be arranged upstream of the conversion reactor CR(1).

[0110] Therefore, it may be preferred that the ammonia provided to the process is in liquid form and passed through an evaporation device to provide a feed gas stream FS(0) which will then enter the first conversion reactor CR(1) of the first zone Z(1).

[0111] Preferably, according to SA(i), the feed gas stream FS(i-1) is contacted with the conversion catalyst C(i) at a pressure in the range of 10 to 100 bar (absolute pressure), more preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure).

[0112] Preferably, according to SA(i), the feed gas stream FS(i-1) is contacted with the conversion catalyst C(i) at a temperature in the range of 50°C to 1100°C, more preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C.

[0113] Preferably, the conversion catalyst C(i) comprises, more preferably consists of, a transition metal supported on a refractory support material.

[0114] Preferably, the transition metal is selected from the group consisting of Fe, Cu, Ni, Co, Ru, Ag, Pd, Rh, Pt, Ir, including combinations of two or more thereof, more preferably selected from the group consisting of Ni, Co, Rh and Ru, including combinations of two or more thereof, more preferably Ni, Co or Ru, and more preferably Ru.

[0115] Preferably, the refractory support material is selected from the group consisting of: zeolite, alumina, silica, titania, zirconia, ceria, lanthanum oxide, praseodymium oxide, neodymium oxide, yttrium oxide, activated carbon, carbon nanotubes and a combination of two or more thereof, more preferably selected from the group consisting of: alumina, silica, titania, zirconia and a combination of two or more thereof, more preferably alumina or zirconia.

[0116] Preferably, the transition metal catalyst supported on the refractory support material is more preferably promoted with a metal selected from the group consisting of lithium, sodium, potassium, cesium, lanthanum, yttrium, neodymium, praseodymium and combinations of two or more thereof, more preferably selected from the group consisting of lithium, sodium, potassium, cesium and combinations of two or more thereof, more preferably the metal is potassium or cesium.

[0117] Preferably, the conversion catalyst C(i) is a molding.

[0118] Preferably at least 95 vol.-%, more preferably 95 to 100 vol.-%, more preferably 98 to 100 vol.-%, more preferably 99 to 100 vol.-%, more preferably 99.5 to 100 vol.-% of the gas stream G(i) consists of NH3, N2 and H2.

[0119] In other words, it is preferred that G(i) consists essentially of, more preferably consists of, NH3, N2 and H2.

[0120] Preferably, the gas stream G(i) has a molar ratio x(G(i)) of H2 to NH3 (calculated as n(H2):n(NH3)=x(G(i))) in the range of 0.01:1 to 500:1, more preferably in the range of 0.05:1 to 200:1, more preferably in the range of 2:1 to 50:1.

[0121] Preferably, the gas stream G(i) has a molar ratio of H2 to N2 y(G(i)) (calculated as n(H2):n(N2)=y(G(i))) in the range of 0.01:1 to 5:1.

[0122] Preferably, G(1) has a molar ratio of H2 to N2 y(G(1)) (calculated as n(H2):n(N2)=y(G(1))) in the range of 2:1 to 5:1, more preferably in the range of 2.5:1 to 3.5:1.

[0123] Preferably, G(i) (wherein i≥1) has a molar ratio of H2 to N2 y(G(i)) (calculated as n(H2):n(N2)=y(G(i))) in the range of 0.05:1 to 2.8:1, more preferably in the range of 0.2:1 to 2.7:1.

[0124] Preferably, the gas stream G(i) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 65 bara, more preferably in the range of 20 to 60 bara.

[0125] Preferably, the gas stream G(i) has a temperature in the range of 50 to 1100°C, more preferably in the range of 100 to 1000°C, more preferably in the range of 350 to 900°C.

[0126] Preferably, the feed gas stream F1(i) is passed through a heat exchanger H(i) before passing through separation stage SB(i). The temperature at which F1(i) leaves H(i) is more preferably lower than the temperature at which F1(i) enters H(i).

[0127] Preferably, the feed gas stream F1(i) has a molar ratio x(F1(i)) of H2 to NH3 in the range of 0.01:1 to 500:1, more preferably in the range of 0.05:1 to 200:1, more preferably in the range of 2:1 to 50:1 (calculated as n(H2):n(NH3)=x(F1(i))=x(G(i))).

[0128] Preferably, the feed gas stream F1(i) has a molar ratio of H2 to N2 y(F1(i)) (calculated as n(H2):n(N2)=y(F1(i))=y(G(i))) in the range of 0.01:1 to 5:1.

[0129] Preferably, F(1) has a molar ratio of H2 to N2 y(F(1)) (calculated as n(H2):n(N2)=y(F(1))) in the range of 2:1 to 5:1, more preferably in the range of 2.5:1 to 3.5:1.

[0130] Preferably, F(i) (wherein i≥1) has a molar ratio of H2 to N2 y(F(i)) (calculated as n(H2):n(N2)=y(F(i))) in the range of 0.05:1 to 2.8:1, more preferably in the range of 0.2:1 to 2.7:1.

[0131] Preferably, the feed gas stream F1(i) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 85 bara, more preferably in the range of 20 to 60 bara.

[0132] Preferably, the feed gas stream F1(i) has a temperature in the range of 250°C to 700°C, more preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C, wherein more preferably said temperature is after having passed through H(i) as defined above.

[0133] Preferably, the volume flow ratio of FS(i-1) to (F1(i)) is in the range of 0.5:1 to 1:1, more preferably in the range of 0.50:1 to 0.95:1.

[0134] Preferably, according to SB(i), the membrane unit M1(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000.

[0135] Preferably, according to SB(i), the membrane unit M1(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0136] Preferably, according to SB(i), at least one membrane included in the membrane unit M1(i) is a palladium metal membrane; wherein preferably according to SB(i), at least one membrane included in the membrane unit M1(i) has a Pd metal membrane of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0137] Preferably, according to SB(i), at least one membrane comprised in membrane unit M1(i) is a palladium metal membrane.

[0138] Preferably, the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, more preferably at least 98.5%, more preferably in the range of 99.0% to 99.9%.

[0139] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0140] Alternatively, the palladium metal film preferably comprises an alloy coating on a substrate, the alloy coating comprising Pd and one or more of Ag, Au, Ru, In, Cu and Y, more preferably Pd and one or more of Ag, Cu and Y, more preferably Pd and Ag, and more preferably consisting of the same.

[0141] Preferably 0.50 to 50 wt.-%, more preferably 1 to 45 wt.-%, more preferably 3 to 35 wt.-%, more preferably 7 to 30 wt.-%, more preferably 8 to 15 wt.-% of the alloy coating consists of metal other than palladium.

[0142] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0143] Preferably, according to SB(i), across the at least one membrane included in the membrane unit M1(i), the pressure ratio calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(i)) at a constant temperature is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, and even more preferably in the range of 2.5:1 to 35:1.

[0144] Preferably, according to SB(i), the permeate gas stream P1(i) has a pressure in the range of 3 to 30 bar (absolute pressure), more preferably in the range of 5 to 20 bar (absolute pressure), and even more preferably in the range of 5 to 15 bar (absolute pressure).

[0145] Preferably, according to SB(i), the permeate gas stream P1(i) has a temperature in the range of 250 °C to 700 °C, more preferably in the range of 300 °C to 600 °C, and even more preferably in the range of 350 °C to 500 °C.

[0146] Preferably, according to SB(i), the permeate gas stream P1(i) further contains NH3 and has a molar ratio of H2 to NH3, x(P1(i)) (calculated as n(H2):n(NH3) = x(P1(i)) > x(F1(i))), greater than 500:1, more preferably in the range of 500:1 to 100,000:1, even more preferably in the range of 1,000:1 to 90,000:1, even more preferably in the range of 15,000:1 to 80,000:1, and even more preferably in the range of 20,000:1 to 60,000:1.

[0147] Preferably, according to SB(i), the permeate gas stream P1(i) has a molar ratio of H2 to N2, y(P1(i)) (calculated as n(H2):n(N2) = y(P1(i)) < y(F1(i))), greater than 500:1, more preferably in the range of 500:1 to 100,000:1, even more preferably in the range of 1,000:1 to 90,000:1, even more preferably in the range of 15,000:1 to 80,000:1, and even more preferably in the range of 20,000:1 to 60,000:1.

[0148] Preferably, P1(i) consists essentially of H2, more preferably consists of it, which means that the H2 purity of the permeate gas stream P1(i) is preferably in the range of 99.9 vol.-% to 99.9999 vol-%, assuming that all components behave as ideal gases. Methods for determining high purity hydrogen depend on the contaminating analytes and are well known to those skilled in the art, with reference to Murugan et al. in "Review of purity analysis methods for performing quality assurance of fuel cell hydrogen" Int. Journal of Hydrogen Energy (2015) p. 4219 for a method of analyzing high purity hydrogen useful to the technician.

[0149] Preferably, according to SB(i), the volume flow ratio of feed gas F1(i) to permeate gas flow P1(i), calculated as (volume flow F1(i) / volume flow P1(i)), is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, and even more preferably in the range of 3:1 to 30:1.

[0150] Preferably, according to SB(i), the retentate gas stream R1(i) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 85 bara, more preferably in the range of 20 to 60 bara.

[0151] Preferably, according to SB(i), the retentate gas stream R1(i) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

[0152] Preferably, according to SB(i), the retentate gas stream R1(i) has a H2 to NH3 molar ratio x(R1(i)) (calculated as n(H2):n(NH3)=x(R1(i))=x(F2)) in the range of 0.1:1 to 100:1, more preferably in the range of 0.5:1 to 60:1, more preferably in the range of 1:1 to 10:1.

[0153] Preferably, according to SB(i), the retentate gas stream R1(i) has a molar ratio of H2 to N2 y(R1(i)) (calculated as n(H2):n(N2)=y(R1(i))=y(F2)) in the range of 0.01:1 to 3:1, more preferably in the range of 0.25:1 to 2:1.

[0154] Preferably, according to SB(i), the volume flow ratio of the feed gas F1(i) to the retentate gas flow R1(i), calculated as (volume flow F1(i) / volume flow R1(i)), is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0155] According to one aspect of the invention, according to SB(i), the membrane unit M1(i) preferably comprises a single membrane.

[0156] According to another aspect of the present invention, according to SB(i), the membrane unit M1(i) preferably comprises two or more membranes, which are connected in parallel and the feed gas flow F1(i) passes through the two or more membranes simultaneously, and the permeate gas flow P1(i) and the retentate gas flow R1(i) are obtained from the membranes simultaneously and in parallel.

[0157] In the context of the present invention, according to SC(i), the feed gas stream F2(i) preferably has a pressure in the range of 10 to 100 bar (absolute pressure), more preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure).

[0158] Preferably, according to SC(i), the feed gas stream F2(i) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

[0159] Preferably, according to SC(i), the feed gas stream F2(i) has a molar ratio of H2 to NH3 x(F2(i)) (calculated as n(H2):n(NH3)=x(F2(i))=x(R1(i))) in the range of 0.1:1 to 100:1, more preferably in the range of 0.5:1 to 60:1, and more preferably in the range of 1:1 to 10:1.

[0160] Preferably, according to SC(i), the feed gas stream F2(i) has a molar ratio of H2 to N2 y(F2(i)) (calculated as n(H2):n(N2)=y(F2(i))=y(R1(i))) in the range of 0.01:1 to 3:1, more preferably in the range of 0.25:1 to 2:1.

[0161] Preferably, according to SB(i) and SC(i), the volume flow ratio of F1(i) to R1(i) calculated as (volume flow F1(i) / volume flow R1(i)) is equal to the volume flow ratio of F1(i) to F2(i) calculated as (volume flow F1(i) / volume flow F2(i)), and is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0162] Preferably, according to SC(i), the membrane unit M2(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2,500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000.

[0163] Preferably, according to SC(i), membrane unit M2(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0164] Preferably, according to SC(i), at least one membrane included in the membrane unit M2(i) is a palladium metal membrane; wherein preferably according to SC(i), at least one membrane included in the membrane unit M2(i) has a Pd metal membrane of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0165] Preferably, according to SC(i), at least one membrane comprised in membrane unit M2(i) is a palladium metal membrane.

[0166] Preferably, the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, more preferably at least 98.5%, more preferably in the range of 99.0% to 99.9%.

[0167] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0168] Alternatively, the palladium metal film preferably comprises an alloy coating on a substrate, the alloy coating comprising Pd and one or more of Ag, Au, Ru, In, Cu and Y, more preferably Pd and one or more of Ag, Cu and Y, more preferably Pd and Ag, and more preferably consisting of the same.

[0169] Preferably 0.50 to 50 wt.-%, more preferably 1 to 45 wt.-%, more preferably 3 to 35 wt.-%, more preferably 7 to 30 wt.-%, more preferably 8 to 15 wt.-% of the alloy coating consists of metal other than palladium.

[0170] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0171] Preferably, according to SC(i), the pressure ratio across the at least one membrane comprised in the membrane unit M2(i), calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at constant temperature It is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, and more preferably in the range of 2.5:1 to 35:1.

[0172] Preferably, according to SC(i), the permeate gas stream P2(i) has a pressure in the range of 1.1 to 30 bara, more preferably in the range of 1.1 to 10 bara, more preferably in the range of 1.1 to 2.5 bara.

[0173] Preferably, according to SC(i), the permeate gas stream P2(i) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

[0174] Preferably, according to SC(i), the permeate gas stream P2(i) further comprises NH3 and has a molar ratio x(P2(i)) of H2 to NH3 greater than 500:1, more preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, more preferably in the range of 20,000:1 to 60,000:1 (calculated as n(H2):n(NH3)=x(P2(i))>x(F2(i))).

[0175] Preferably, according to SC(i), the permeate gas stream P2(i) further comprises H2 and has a molar ratio y(P2(i)) of H2 to N2 (calculated as n(H2):n(N2)=y(P2(i)) greater than 500:1, more preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, more preferably in the range of 20,000:1 to 60,000:1 <y(F2(i)))。

[0176] Preferably, P2(i) consists essentially of H2, more preferably consists of it, which means that the H2 purity is preferably in the range of 99.9 vol.-% to 99.9999 vol-%, assuming that all components behave as ideal gases. Methods for determining high purity hydrogen depend on the contaminating analytes and are well known to those skilled in the art, with reference to Murugan et al. in "Review of purity analysis methods for performing quality assurance of fuel cell hydrogen" Int. Journal of Hydrogen Energy (2015) p. 4219 for a method of analyzing high purity hydrogen useful to technicians.

[0177] Preferably, according to SC(i), the volume flow ratio of feed gas F2(i) to permeate gas flow P2(i), calculated as (volume flow F2(i) / volume flow P2(i)), is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, and even more preferably in the range of 3:1 to 30:1.

[0178] Preferably, according to SC(i), the retentate gas stream R2(i) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 85 bara, more preferably in the range of 20 to 60 bara.

[0179] Preferably, according to SC(i), the retentate gas stream R2(i) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

[0180] Preferably, according to SC(i), the retentate gas stream R2(i) has a H2 to NH3 molar ratio x(R2(i)) (calculated as n(H2):n(NH3)=x(R2(i))=x(FS(i))) in the range of 0.05:1 to 100:1, more preferably in the range of 0.1:1 to 30:1, more preferably in the range of 0.2:1 to 5:1.

[0181] Preferably, according to SC(i), the retentate gas stream R2(i) has a H2 to N2 molar ratio y(R2(i)) (calculated as n(H2):n(N2)=y(R2(i))=y(FS(i))) in the range of 0.01:1 to 2:1, more preferably in the range of 0.03:1 to 2:1, more preferably in the range of 0.05:1 to 1.5:1.

[0182] Preferably, according to SC(i), the volume flow ratio of F2(i) to R2(i) calculated as (volume flow F2(i) / volume flow R2(i)) is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0183] Preferably, according to SC(i), the feed stream FS(i) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 85 bara, more preferably in the range of 20 to 60 bara.

[0184] Preferably, according to SC(i), the feed stream FS(i) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

[0185] Preferably, according to SC(i), the feed stream FS(i) has a molar ratio of H2 to NH3 x(F2(i)) (calculated as n(H2):n(NH3)=x(FS(i))=x(R2(i))) in the range of 0.05:1 to 100:1, more preferably in the range of 0.1:1 to 30:1, more preferably in the range of 0.2:1 to 5:1.

[0186] Preferably, according to SC(i), the feed stream FS(i) has a H2 to N2 molar ratio y(FS(i)) (calculated as n(H2):n(N2)=y(FS(i))=y(R2(i))) in the range of 0.01:1 to 2:1, more preferably in the range of 0.03:1 to 2:1, more preferably in the range of 0.05:1 to 1.5:1.

[0187] Preferably, according to SC(i), the volume flow ratio of F2(i) to R2(i) calculated as (volume flow F2(i) / volume flow R2(i)) is equal to the volume flow ratio of F2(i) to FS(i) calculated as (volume flow F2(i) / volume flow FS(i)), and is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0188] Preferably, the retentate gas stream R2(n) has a pressure in the range of 10 to 100 bara, more preferably in the range of 15 to 85 bara, more preferably in the range of 20 to 60 bara, according to SC(n).

[0189] Preferably, the retentate gas stream R2(n) has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C, according to SC(n).

[0190] Preferably, according to SC(n), the retentate gas stream R2(n) has a H2 to NH3 molar ratio x(R2(i)) (calculated as n(H2):n(NH3)=x(R2(n))) in the range of 0.05:1 to 100:1, more preferably in the range of 0.1:1 to 30:1, more preferably in the range of 0.2:1 to 5:1.

[0191] Preferably, according to SC(n), the retentate gas stream R2(n) has a H2 to N2 molar ratio y(R2(i)) (calculated as n(H2):n(N2)=y(R2(n))) in the range of 0.01:1 to 2:1, more preferably in the range of 0.03:1 to 2:1, and more preferably in the range of 0.05:1 to 1.5:1.

[0192] Preferably, according to SC(n), the volume flow ratio of F2(n) to R2(n) calculated as (volume flow F2(n) / volume flow R2(n)) is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0193] According to one aspect of the present invention, in SC(i), the membrane unit M2(i) preferably comprises a single membrane.

[0194] According to another aspect of the present invention, in SC(i), the membrane unit M2(i) preferably comprises two or more membranes, which are connected in parallel and the feed gas flow F2(i) passes through the two or more membranes simultaneously, and the permeate gas flow P2(i) and the retentate gas flow R2(i) are obtained from the membranes simultaneously in parallel.

[0195] In the context of the present invention, the volume flow ratio of FS(i-1) to (FS(i)) is preferably in the range of 1.1:1 to 3:1, more preferably in the range of 1.2:1 to 2.5:1.

[0196] Preferably, the ratio of the pressure of the permeate gas stream P1(i) to the permeate gas stream P2(i) is in the range of 50:1 to 1.5:1, more preferably in the range of 20:1 to 2:1, more preferably in the range of 15:1 to 3:1, more preferably in the range of 12:1 to 4:1.

[0197] Preferably, the volume flow ratio of FS(n-1) to R2(n) is in the range of 1.05:1 to 4:1, more preferably in the range of 1.1 to 3, and more preferably in the range of 1.5 to 2.5.

[0198] Preferably, for n=2, the device for recovering H2 from converted NH3 comprises two zones Z(1) and Z(2) connected in series,

[0199] Among them, zone Z(1) includes

[0200] a conversion reactor CR (1) comprising a catalyst C (1) for converting NH3 to give H2,

[0201] - the first membrane unit M1 (1) and

[0202] - a second membrane unit M2 (1),

[0203] wherein in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1), wherein Z(1) is the most upstream region and Z(2) is the most downstream region, and

[0204] Among them, zone Z(2) includes

[0205] a conversion reactor CR (2) comprising a catalyst C (2) for converting NH 3 to give H 2 ,

[0206] - first membrane unit M1(2) and

[0207] - a second membrane unit M2 (2),

[0208] where in Z(2), CR(2) is located upstream of M1(2) and M2(2) is located downstream of M1(2),

[0209] The method includes

[0210] (a) providing a feed gas stream FS(0) comprising NH3;

[0211] (b) Two consecutive processing stages S(1) and S(2)

[0212] Where S(1) includes

[0213] The conversion phase SA (1) includes

[0214] - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(1) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(1) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0215] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0216] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0217] The separation stage SB (1) comprises

[0218] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0219] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0220] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(1) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0221] o a permeate gas stream P1(1) comprising H2; and

[0222] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0223] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0224] The separation stage SC (1) comprises

[0225] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(1) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0226] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0227] o a permeate gas stream P2(1) comprising H2; and

[0228] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0229] - removing the gas stream R2(1) from Z(1);

[0230] wherein the gas stream R2(1) is removed as a feed stream FS(1) having the same chemical and physical composition and molar ratio x(R2(1))=x(FS(1)) as R2(1); and

[0231] Where S(2) includes

[0232] The conversion phase SA (2) includes

[0233] - feeding a gas stream FS(1) into a conversion reactor CR(2) comprised in Z(2) and contacting said stream FS(1) with C(2) in CR(2) to obtain a gas stream G(2) comprising NH3, N2 and H2, said gas stream G(2) having a molar ratio n(H2):n(NH3)=x(G(2));

[0234] - removing the gas stream G(2) comprising NH3, N2 and H2 from CR(2);

[0235] - passing this gas stream G(2) as feed gas stream F1(2) through a separation stage SB(2), F1(2) having the same chemical composition as G(2) and the molar ratio x(G(2))=x(F1(2));

[0236] The separation stage SB (2) comprises

[0237] - passing the feed gas stream F1(2) through a first membrane unit M1(2) comprising at least one membrane of Z(2) at a pressure ratio φ,

[0238] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0239] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(2) / pressure of the permeate gas stream P1(2)) at constant temperature, is greater than 1, obtaining

[0240] o a permeate gas stream P1 (2) comprising H2; and

[0241] o A retentate gas stream R1(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(2)); x(R1(2)) <x(F1(2));

[0242] - passing the retentate gas stream R1(2) through a separation stage SC(2) as feed gas stream F2(2), F2(2) having the same chemical and physical composition as R1(2) and the molar ratio x(R1(2))=x(F2(2));

[0243] The separation stage SC (2) comprises

[0244] - passing the feed gas stream F2(2) through a second membrane unit M2(2) of Z(2) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0245] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(2) / pressure of the permeate gas stream P2(2)) at constant temperature, is greater than 1, obtaining

[0246] o a permeate gas stream P2(2) comprising H2; and

[0247] o A retentate gas stream R2(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(2)); x(R2(2)) <x(F2(2));

[0248] - removing the gas flow R2(2) from Z(2);

[0249] wherein the gas stream R2(2) is removed as a product gas stream;

[0250] wherein the volume flow ratio of FS(0) to FS(1) is in the range of 1.05:1 to 4:1;

[0251] More preferably, the volume flow ratio of FS(1) to R2(2) is in the range of 1.05:1 to 4:1.

[0252] Preferably, for n=3, the device for recovering H2 from converted NH3 comprises three zones Z(1), Z(2) and Z(3) connected in series,

[0253] Among them, zone Z(1) includes

[0254] a conversion reactor CR (1) comprising a catalyst C (1) for converting NH3 to give H2,

[0255] - the first membrane unit M1 (1) and

[0256] - a second membrane unit M2 (1),

[0257] wherein in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1), wherein Z(1) is the most upstream zone and Z(2) is downstream of Z(1) and Z(3),

[0258] Among them, zone Z(2) includes

[0259] a conversion reactor CR (2) comprising a catalyst C (2) for converting NH 3 to give H 2 ,

[0260] - first membrane unit M1(2) and

[0261] - a second membrane unit M2 (2),

[0262] wherein in Z(2), CR(2) is located upstream of M1(2) and M2(2) is located downstream of M1(2), and

[0263] Among them, zone Z(3) includes

[0264] a conversion reactor CR (3) comprising a catalyst C (3) for converting NH3 to give H2,

[0265] - first membrane unit M1 (3) and

[0266] - a second membrane unit M2 (3),

[0267] Wherein in Z(3), CR(3) is located upstream of M1(3) and M2(3) is located downstream of M1(3),

[0268] The method includes

[0269] (a) providing a feed gas stream FS(0) comprising NH3;

[0270] (b) Three consecutive processing stages S(1), S(2) and S(3)

[0271] Where S(1) includes

[0272] The conversion phase SA (1) includes

[0273] - feeding a feed gas stream FS(0) into a conversion reactor CR(1) comprised in Z(1) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(1) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0274] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0275] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0276] The separation stage SB (1) comprises

[0277] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0278] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0279] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(1) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0280] o a permeate gas stream P1(1) comprising H2; and

[0281] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0282] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0283] The separation stage SC (1) comprises

[0284] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(1) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0285] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0286] o a permeate gas stream P2(1) comprising H2; and

[0287] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0288] - removing the gas stream R2(1) from Z(1);

[0289] wherein the gas stream R2(1) is removed as a feed stream FS(1) having the same chemical and physical composition and molar ratio x(R2(1))=x(FS(1)) as R2(1); and

[0290] Where S(2) includes

[0291] The conversion phase SA (2) includes

[0292] - feeding a gas stream FS(1) into a conversion reactor CR(2) comprised in Z(2) and contacting said stream FS(1) with C(2) in CR(2) to obtain a gas stream G(2) comprising NH3, N2 and H2, said gas stream G(2) having a molar ratio n(H2):n(NH3)=x(G(2));

[0293] - removing the gas stream G(2) comprising NH3, N2 and H2 from CR(2);

[0294] - passing this gas stream G(2) as feed gas stream F1(2) through a separation stage SB(2), F1(2) having the same chemical composition as G(2) and the molar ratio x(G(2))=x(F1(2));

[0295] The separation stage SB (2) comprises

[0296] - passing the feed gas stream F1(2) through a first membrane unit M1(2) comprising at least one membrane of Z(2) at a pressure ratio φ,

[0297] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0298] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(2) / pressure of the permeate gas stream P1(2)) at constant temperature, is greater than 1, obtaining

[0299] o a permeate gas stream P1 (2) comprising H2; and

[0300] o A retentate gas stream R1(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(2)); x(R1(2)) <x(F1(2));

[0301] - passing the retentate gas stream R1(2) through a separation stage SC(2) as feed gas stream F2(2), F2(2) having the same chemical and physical composition as R1(2) and the molar ratio x(R1(2))=x(F2(2));

[0302] The separation stage SC (2) comprises

[0303] - passing the feed gas stream F2(2) through a second membrane unit M2(2) of Z(2) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0304] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(2) / pressure of the permeate gas stream P2(2)) at constant temperature, is greater than 1, obtaining

[0305] o a permeate gas stream P2(2) comprising H2; and

[0306] o A retentate gas stream R2(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(2)); x(R2(2)) <x(F2(2));

[0307] - removing the gas flow R2(2) from Z(2);

[0308] wherein a gas stream R2(2) is removed as a feed stream FS(2), FS(2) having the same chemical and physical composition and molar ratio x(R2(2))=x(FS(2)) as R2(2); and

[0309] Where S(3) includes

[0310] The conversion phase SA (3) includes

[0311] - feeding a feed gas stream FS(2) into a conversion reactor CR(3) comprised in Z(3) and contacting said stream FS(2) with C(3) in CR(3) to obtain a gas stream G(3) comprising NH3, N2 and H2, said gas stream G(3) having a molar ratio n(H2):n(NH3)=x(G(3));

[0312] - removing the gas stream G (3) comprising NH3, N2 and H2 from CR (3);

[0313] - passing this gas stream G(3) as feed gas stream F1(3) through a separation stage SB(3), F1(3) having the same chemical composition as G(3) and the molar ratio x(G(3))=x(F1(3));

[0314] The separation stage SB (3) comprises

[0315] - passing the feed gas stream F1 (3) through a first membrane unit M1 (3) comprising at least one membrane of Z(3) at a pressure ratio φ,

[0316] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0317] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1 (3) / pressure of the permeate gas stream P1 (3)) at constant temperature, is greater than 1, obtaining

[0318] o a permeate gas stream P1 (3) comprising H2; and

[0319] o A retentate gas stream R1(3) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(3)); x(R1(3)) <x(F1(3));

[0320] - passing the retentate gas stream R1(3) through a separation stage SC(3) as feed gas stream F2(3), F2(3) having the same chemical and physical composition as R1(3) and the molar ratio x(R1(3))=x(F2(3));

[0321] The separation stage SC (3) comprises

[0322] - passing the feed gas stream F2(3) through a second membrane unit M2(3) of Z(3) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0323] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(3) / pressure of the permeate gas stream P2(3)) at constant temperature, is greater than 1, obtaining

[0324] o a permeate gas stream P2 (3) comprising H2; and

[0325] o A retentate gas stream R2(3) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(3)); x(R2(3)) <x(F2(3));

[0326] - removing the gas flow R2(3) from Z(3);

[0327] wherein the gas stream R2(3) is removed as a product gas stream;

[0328] The volume flow ratio of FS(0) to FS(1) is in the range of 1.05:1 to 4:1.

[0329] wherein the volume flow ratio of FS(1) to FS(2) is in the range of 1.05:1 to 4:1;

[0330] More preferably, the volume flow ratio of FS(1) to R2(2) is in the range of 1.05:1 to 4:1.

[0331] The invention further relates to a process for recovering H2 from the conversion of NH3 in a plant comprising a zone Z(1) comprising a conversion reactor CR(1), a first membrane unit M1(1) and a second membrane unit M2(1), the conversion reactor comprising a catalyst C(1) for converting NH3 to give H2,

[0332] where in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1),

[0333] The method includes

[0334] (a) providing a feed gas stream FS(0) comprising NH3;

[0335] (b) Processing stage S(1)

[0336] Where S(1) includes

[0337] The conversion phase SA (1) includes

[0338] - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(i) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0339] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0340] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0341] The separation stage SB (1) comprises

[0342] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0343] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0344] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0345] o a permeate gas stream P1(1) comprising H2; and

[0346] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0347] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0348] The separation stage SC (1) comprises

[0349] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0350] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0351] o a permeate gas stream P2(1) comprising H2; and

[0352] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0353] - removing the gas stream R2(1) from Z(1);

[0354] wherein the gas stream R2(1) is removed from Z(1) as a product gas stream;

[0355] Preferably, the volume flow ratio of FS(0) to R2(1) is in the range of 1.05:1 to 4:1.

[0356] For this alternative using only one zone Z(1), it should be noted that the preferred ranges and parameters defined for the alternative with two or more zones are the same as for the concept of only one zone (if applicable). Therefore, the above-mentioned Z(i), CR(i), C(i), SA(i), SB(i), SC(i), etc. are applicable and explicitly disclosed with respect to Z(1) in this alternative with only one zone Z(1).

[0357] The invention further relates to a device for recovering H2 from converting NH3, the device comprising

[0358] n zones Z(i), where i=1…n, where n≥1,

[0359] wherein, when n≥2, the n zones Z(i) are connected in series and Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0360] Each zone Z(i) includes

[0361] The conversion reactor unit U.CR(i) comprises

[0362] - a supply device for supplying a feed stream FS(i-1) comprising NH 3 to the conversion reactor CR(i);

[0363] a conversion reactor CR(i) for converting NH3 into a gas stream G(i) comprising NH3, N2 and H2, the conversion reactor CR(i) comprising a conversion catalyst C(i);

[0364] - outlet means for removing the gas stream G(i) as feed gas stream F1(i) from CR(i) to the membrane separation unit U.M1(i);

[0365] The first membrane separation unit U.M1(i) comprises

[0366] - means for sending the feed gas stream F1(i) to the first membrane unit M1(i);

[0367] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0368] - outlet means for removing the permeate gas stream P1 (i) from the membrane unit M1 (i);

[0369] - outlet means for removing a retentate gas stream R1 (i) from the membrane unit M1 (i);

[0370] The second membrane separation unit U.M2(i) comprises

[0371] - means for feeding the retentate gas stream R1(i) as feed gas stream F2(i) to the second membrane unit M2(i);

[0372] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0373] - outlet means for removing the permeate gas stream P2(i) from the membrane unit M2(i);

[0374] outlet means for removing a retentate gas stream R2(i) from Z(i); and

[0375] means for sending R2(i) removed from Z(i) as feed stream FS(i) to Z(i+1) when n≥2 and i≠n;

[0376] In Z(i), U.CR(i) is located upstream of U.M1(i) and U.M2(i) is located downstream of U.M1(i).

[0377] Preferably, n=1 to 10, more preferably n=1 to 5, more preferably n=1, 2, 3 or 4, more preferably n=1 or 2 or 3.

[0378] Preferably, no vacuum device or compressor is arranged downstream of the conversion reactor CR(i) according to U.CR(i); preferably, wherein the feed gas, the permeate stream and / or the retentate stream for carrying hydrogen have no compressor or vacuum device connected to or operating with any unit of the device.

[0379] Preferably, the present invention further relates to a device for recovering H2 from converting NH3, the device comprising

[0380] n zones Z(i), wherein n=1 ... n, wherein n≥1, more preferably n=1 to 10, more preferably n=1 to 5, more preferably 1, 2, 3 or 4, more preferably n=1 or 2 or 3,

[0381] wherein, when n≥2, the n zones Z(i) are connected in series and Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0382] Each zone Z(i) includes

[0383] The conversion reactor unit U.CR(i) comprises

[0384] - a supply device for supplying a feed stream FS(i-1) comprising NH 3 to the conversion reactor CR(i);

[0385] a conversion reactor CR(i) for converting NH3 into a gas stream G(i) comprising NH3, N2 and H2, the conversion reactor CR(i) comprising a conversion catalyst C(i);

[0386] - outlet means for removing the gas stream G(i) as feed gas stream F1(i) from CR(i) to the membrane separation unit U.M1(i);

[0387] The first membrane separation unit U.M1(i) comprises

[0388] - means for sending the feed gas stream F1(i) to the first membrane unit M1(i);

[0389] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0390] - outlet means for removing the permeate gas stream P1 (i) from the membrane unit M1 (i);

[0391] - outlet means for removing a retentate gas stream R1 (i) from the membrane unit M1 (i);

[0392] The second membrane separation unit U.M2(i) comprises

[0393] - means for feeding the retentate gas stream R1(i) as feed gas stream F2(i) to the second membrane unit M2(i);

[0394] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0395] - outlet means for removing the permeate gas stream P2(i) from the membrane unit M2(i);

[0396] outlet means for removing a retentate gas stream R2(i) from Z(i); and

[0397] means for sending R2(i) removed from Z(i) as feed stream FS(i) to Z(i+1) when n≥2 and i≠n;

[0398] Wherein in Z(i), U.CR(i) is located upstream of U.M1(i) and U.M2(i) is located downstream of U.M1(i);

[0399] More preferably, no vacuum device or compressor is arranged downstream of the conversion reactor CR(i) according to U.CR(i); more preferably, none of the feed gas, permeate flow and / or retentate flow for carrying hydrogen has a compressor or vacuum device connected to or operating together with any unit of the device.

[0400] Preferably, the conversion reactor unit U.CR(i) comprises heating means for heating the conversion reactor CR(i) to a temperature in the range of 50°C to 1100°C, more preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C.

[0401] Preferably, the conversion catalyst C(i) comprises, more preferably consists of, a transition metal supported on a refractory support material.

[0402] Preferably, the transition metal is selected from the group consisting of Fe, Cu, Ni, Co, Ru, Ag, Pd, Rh, Pt, Ir, including combinations of two or more thereof, more preferably selected from the group consisting of Ni, Co, Rh and Ru, including combinations of two or more thereof, more preferably Ni, Co or Ru, and more preferably Ru.

[0403] Preferably, the refractory support material is selected from the group consisting of: zeolite, alumina, silica, titania, zirconia, ceria, lanthanum oxide, praseodymium oxide, neodymium oxide, yttrium oxide, activated carbon, carbon nanotubes and a combination of two or more thereof, more preferably selected from the group consisting of: alumina, silica, titania, zirconia and a combination of two or more thereof, more preferably alumina or zirconia.

[0404] Preferably, the transition metal catalyst supported on the refractory support material is more preferably promoted with a metal selected from the group consisting of lithium, sodium, potassium, cesium, lanthanum, yttrium, neodymium, praseodymium and combinations of two or more thereof, more preferably selected from the group consisting of lithium, sodium, potassium, cesium and combinations of two or more thereof, more preferably potassium or cesium.

[0405] Preferably, the conversion catalyst C(i) is a molding.

[0406] Preferably, the conversion reactor unit U.CR(i) comprises a heat exchange device H(i) which is arranged downstream of the outlet device for removing the gas flow G(i) from CR(i) and upstream of the device for sending the feed gas flow F1(i) to the first membrane unit M1(i).

[0407] Preferably, the conversion reactor unit U.CR(i) comprises a heat exchange device H(i) for adjusting the temperature of the feed gas stream F1(i) to a range of 250°C to 700°C; more preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0408] Preferably, membrane unit M1(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2,500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5000 to 800,000, more preferably in the range of 6000 to 600,000.

[0409] Preferably, the membrane unit M1(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0410] Preferably, at least one membrane included in the membrane unit M1(i) is a palladium metal membrane; wherein preferably, the at least one membrane included in the membrane unit M1(i) has a thermal conductivity of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0411] Preferably, at least one membrane comprised in the membrane unit M1 (i) is a palladium metal membrane.

[0412] Preferably, the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, more preferably at least 98.5%, more preferably in the range of 99.0% to 99.9%.

[0413] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0414] Alternatively, the palladium metal film preferably comprises an alloy coating on a substrate, the alloy coating comprising Pd and one or more of Ag, Au, Ru, In, Cu and Y, more preferably Pd and one or more of Ag, Cu and Y, more preferably Pd and Ag, and more preferably consisting of the same.

[0415] Preferably 0.50 to 50 wt.-%, more preferably 1 to 45 wt.-%, more preferably 3 to 35 wt.-%, more preferably 7 to 30 wt.-%, more preferably 8 to 15 wt.-% of the alloy coating consists of metal other than palladium.

[0416] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0417] According to one aspect of the present invention, the membrane unit M1 (i) preferably comprises a single membrane.

[0418] According to another aspect of the present invention, the membrane unit M1(i) preferably includes two or more membranes, which are connected in parallel to a device for sending a feed gas flow F1(i) to the first membrane unit M1(i), and are connected in parallel to an outlet device for removing a permeate gas flow P1(i) from the first membrane unit M1(i), and are connected in parallel to an outlet device for removing a retentate gas flow R1(i) from the first membrane unit M1(i).

[0419] In the context of the present invention, the membrane unit M2(i) preferably comprises at least one membrane having a H2 / NH3 selectivity of at least 2500, more preferably in the range of 2500 to 1,000,000, more preferably in the range of 4500 to 900,000, more preferably in the range of 5000 to 800,000, more preferably in the range of 6000 to 600,000.

[0420] Preferably, the membrane unit M2(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0421] Preferably, at least one membrane included in the membrane unit M2(i) is a palladium metal membrane; wherein preferably, the at least one membrane included in the membrane unit M2(i) has a thermal conductivity of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0422] Preferably, at least one membrane comprised in the membrane unit M2(i) is a palladium metal membrane.

[0423] Preferably, the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, more preferably at least 98.5%, more preferably in the range of 99.0% to 99.9%.

[0424] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0425] Alternatively, the palladium metal film preferably comprises an alloy coating on a substrate, the alloy coating comprising Pd and one or more of Ag, Au, Ru, In, Cu and Y, more preferably Pd and one or more of Ag, Cu and Y, more preferably Pd and Ag, and more preferably consisting of the same.

[0426] Preferably 0.50 to 50 wt.-%, more preferably 1 to 45 wt.-%, more preferably 3 to 35 wt.-%, more preferably 7 to 30 wt.-%, more preferably 8 to 15 wt.-% of the alloy coating consists of metal other than palladium.

[0427] Preferably, the substrate of the palladium metal membrane is selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide. For acceptable substrate materials for palladium-containing membranes, further reference is made to Pal N. et al., A review on types, fabrication and support material of hydrogen separation membrane, Materials Today: Proceedings, Vol. 28, Part 3, 2020, pp. 1386-1391.

[0428] According to one aspect of the invention, the membrane unit M2(i) preferably comprises a single membrane.

[0429] According to another aspect of the present invention, the membrane unit M2(i) preferably includes two or more membranes, which are connected in parallel to a device for sending a feed gas flow F2(i) to the second membrane unit M2(i), and are connected in parallel to an outlet device for removing a permeate gas flow P2(i) from the first membrane unit M1(i), and are connected in parallel to an outlet device for removing a retentate gas flow R2(i) from the second membrane unit M2(i).

[0430] Preferably, the apparatus does not comprise an ammonia condenser and / or does not comprise a gas-liquid phase separator, more preferably the apparatus does not comprise an ammonia condenser and does not comprise a gas-liquid phase separator.

[0431] Preferably, the present invention further relates to a device for recovering H2 from converting NH3, the device comprising

[0432] n zones Z(i), where i=1…n, where n≥1,

[0433] wherein, when n≥2, the n zones Z(i) are connected in series and Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0434] Each zone Z(i) includes

[0435] The conversion reactor unit U.CR(i) comprises

[0436] - a supply device for supplying a feed stream FS(i-1) comprising NH 3 to the conversion reactor CR(i);

[0437] a conversion reactor CR(i) for converting NH3 into a gas stream G(i) comprising NH3, N2 and H2, the conversion reactor CR(i) comprising a conversion catalyst C(i);

[0438] - outlet means for removing the gas stream G(i) as feed gas stream F1(i) from CR(i) to the membrane separation unit U.M1(i);

[0439] The first membrane separation unit U.M1(i) comprises

[0440] - means for sending the feed gas stream F1(i) to the first membrane unit M1(i);

[0441] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0442] - outlet means for removing the permeate gas stream P1 (i) from the membrane unit M1 (i);

[0443] - outlet means for removing a retentate gas stream R1 (i) from the membrane unit M1 (i);

[0444] The second membrane separation unit U.M2(i) comprises

[0445] - means for feeding the retentate gas stream R1(i) as feed gas stream F2(i) to the second membrane unit M2(i);

[0446] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0447] - outlet means for removing the permeate gas stream P2(i) from the membrane unit M2(i);

[0448] outlet means for removing a retentate gas stream R2(i) from Z(i); and

[0449] means for sending R2(i) removed from Z(i) as feed stream FS(i) to Z(i+1) when n≥2 and i≠n;

[0450] Wherein in Z(i), U.CR(i) is located upstream of U.M1(i) and U.M2(i) is located downstream of U.M1(i);

[0451] The device does not include an ammonia condenser and / or does not include a gas-liquid phase separator, and more preferably the device does not include an ammonia condenser and does not include a gas-liquid phase separator.

[0452] In the context of the present invention, for n=2, the apparatus comprises 2 zones Z(1) and Z(2) connected in series, where Z(1) is the most upstream zone and Z(2) is the most downstream zone,

[0453] Among them, zone Z(1) includes

[0454] The conversion reactor unit U.CR (1) comprises

[0455] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0456] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0457] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0458] The first membrane separation unit U.M1 (1) comprises

[0459] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0460] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0461] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0462] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0463] The second membrane separation unit U.M2(1) comprises

[0464] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0465] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0466] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0467] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0468] means for passing R2(1) removed from Z(1) as feed stream FS(1) to Z(2),

[0469] where in Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1),

[0470] Among them, zone Z(2) includes

[0471] The conversion reactor unit U.CR (2) comprises

[0472] - a supply device for supplying a feed stream FS (1) comprising NH 3 to the conversion reactor CR (2);

[0473] a conversion reactor CR (2) for converting NH3 into a gas stream G (2) comprising NH3, N2 and H2, the conversion reactor CR (2) comprising a conversion catalyst C (2);

[0474] - outlet means for removing the gas stream G(2) as feed gas stream F1(2) from CR(2) to the membrane separation unit U.M1(2);

[0475] The first membrane separation unit U.M1 (2) comprises

[0476] - means for sending the feed gas stream F1 (2) to the first membrane unit M1 (2);

[0477] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0478] - outlet means for removing the permeate gas stream P1 (2) from the membrane unit M1 (2);

[0479] - outlet means for removing the retentate gas stream R1 (2) from the membrane unit M1 (2);

[0480] The second membrane separation unit U.M2(2) comprises

[0481] - means for feeding the retentate gas stream R1 (2) as feed gas stream F2 (2) to the second membrane unit M2 (2);

[0482] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0483] - outlet means for removing the permeate gas stream P2(2) from the membrane unit M2(2);

[0484] outlet means for removing the retentate gas stream R2(2) from Z(2),

[0485] In Z(2), U.CR(2) is located upstream of U.M1(2) and U.M2(2) is located downstream of U.M1(2).

[0486] Preferably, for n=3, the device comprises 3 zones Z(1), Z(2) and Z(3) connected in series,

[0487] Among them, Z(1) is the most upstream zone, and Z(3) is the most downstream zone.

[0488] Among them, zone Z(1) includes

[0489] The conversion reactor unit U.CR (1) comprises

[0490] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0491] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0492] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0493] The first membrane separation unit U.M1 (1) comprises

[0494] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0495] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0496] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0497] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0498] The second membrane separation unit U.M2(1) comprises

[0499] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0500] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0501] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0502] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0503] means for passing R2(1) removed from Z(1) as feed stream FS(1) to Z(2),

[0504] where in Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1),

[0505] Among them, zone Z(2) includes

[0506] The conversion reactor unit U.CR (2) comprises

[0507] - a supply device for supplying a feed stream FS (1) comprising NH 3 to the conversion reactor CR (2);

[0508] a conversion reactor CR (2) for converting NH3 into a gas stream G (2) comprising NH3, N2 and H2, the conversion reactor CR (2) comprising a conversion catalyst C (2);

[0509] - outlet means for removing the gas stream G(2) as feed gas stream F1(2) from CR(2) to the membrane separation unit U.M1(2);

[0510] The first membrane separation unit U.M1 (2) comprises

[0511] - means for sending the feed gas stream F1 (2) to the first membrane unit M1 (2);

[0512] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0513] - outlet means for removing the permeate gas stream P1 (2) from the membrane unit M1 (2);

[0514] - outlet means for removing the retentate gas stream R1 (2) from the membrane unit M1 (2);

[0515] The second membrane separation unit U.M2(2) comprises

[0516] - means for feeding the retentate gas stream R1 (2) as feed gas stream F2 (2) to the second membrane unit M2 (2);

[0517] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0518] - outlet means for removing the permeate gas stream P2(2) from the membrane unit M2(2);

[0519] outlet means for removing a retentate gas stream R2(2) from Z(2);

[0520] means for passing R2(2) removed from Z(2) as feed stream FS(2) to Z(3),

[0521] wherein in Z(2), U.CR(2) is located upstream of U.M1(2) and U.M2(2) is located downstream of U.M1(2);

[0522] Among them, zone Z(3) includes

[0523] The conversion reactor unit U.CR (3) comprises

[0524] - a supply device for supplying a feed stream FS (2) comprising NH 3 to the conversion reactor CR (3);

[0525] a conversion reactor CR (3) for converting NH3 into a gas stream G (3) comprising NH3, N2 and H2, the conversion reactor CR (3) comprising a conversion catalyst C (3);

[0526] - outlet means for removing the gas stream G(3) as feed gas stream F1(3) from CR(3) to the membrane separation unit U.M1(3);

[0527] The first membrane separation unit U.M1 (3) comprises

[0528] - means for sending the feed gas stream F1 (3) to the first membrane unit M1 (3);

[0529] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0530] - outlet means for removing the permeate gas stream P1 (3) from the membrane unit M1 (3);

[0531] - outlet means for removing the retentate gas stream R1 (3) from the membrane unit M1 (3);

[0532] The second membrane separation unit U.M2 (3) comprises

[0533] - means for feeding the retentate gas stream R1 (3) as feed gas stream F2 (3) to the second membrane unit M2 (3);

[0534] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0535] - outlet means for removing the permeate gas stream P2 (3) from the membrane unit M2 (3);

[0536] An outlet device for removing the retentate gas stream R2(3) from Z(3), wherein in Z(3) U.CR(3) is located upstream of U.M1(3) and U.M2(3) is located downstream of U.M1(3).

[0537] Preferably, the device comprises a single zone Z(1), wherein the zone Z(1) comprises

[0538] The conversion reactor unit U.CR (1) comprises

[0539] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0540] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0541] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0542] The first membrane separation unit U.M1 (1) comprises

[0543] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0544] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0545] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0546] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0547] The second membrane separation unit U.M2(1) comprises

[0548] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0549] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0550] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0551] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0552] In Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1).

[0553] The invention further relates to the use of the device according to the invention and as described above in a process for recovering H 2 from converting NH 3 , preferably in a process according to the invention.

[0554] The present invention is further illustrated by the following groups of embodiments and the combination of embodiments obtained by the dependencies and back-references as shown. In particular, it should be noted that in each case where a series of embodiments is mentioned, for example, in the context of a term such as "as any one of embodiments 1 to 4", each embodiment in this series is intended to be clearly disclosed to the technician, that is, the wording of this term should be understood by the technician as synonymous with "as any one of embodiments 1, 2, 3 and 4". In addition, it is clearly pointed out that the following group of embodiments is not a group of claims that determine the scope of protection, but represents an appropriate structural part of this specification related to the general and preferred aspects of the present invention.

[0555] 1. A method for recovering H2 from the conversion of NH3 in a device comprising n zones Z(i) connected in series, where i=1 ... n, where n≥2,

[0556] Each zone Z(i) includes

[0557] a conversion reactor CR(i) comprising a catalyst C(i) for converting NH3 to give H2,

[0558] - the first membrane unit M1(i) and

[0559] - a second membrane unit M2(i),

[0560] wherein in Z(i), CR(i) is located upstream of M1(i) and M2(i) is located downstream of M1(i), wherein Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0561] The method includes

[0562] (a) providing a feed gas stream FS(0) comprising NH3;

[0563] (b) n consecutive processing stages S(i), i=1…n,

[0564] Among them, in each S(i), S(i) includes

[0565] The conversion phase SA(i) includes

[0566] - feeding a gas stream FS(i-1) into a conversion reactor CR(i) included in Z(i) and contacting said stream FS(i-1) with C(i) in CR(i) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(i) having a molar ratio n(H2):n(NH3)=x(G(i));

[0567] - removing the gas stream G(i) comprising NH3, N2 and H2 from CR(i);

[0568] - passing this gas stream G(i) as feed gas stream F1(i) through a separation stage SB(i), F1(i) having the same chemical composition as G(i) and the molar ratio x(G(i))=x(F1(i));

[0569] The separation stage SB(i) comprises

[0570] - passing the feed gas stream F1(i) through a first membrane unit M1(i) comprising at least one membrane of Z(i) at a pressure ratio φ,

[0571] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0572] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(i)) at constant temperature, is greater than 1, obtaining

[0573] o a permeate gas stream P1(i) comprising H2; and

[0574] o A retentate gas stream R1(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(i)); x(R1(i)) <x(F1(i));

[0575] - passing the retentate gas stream R1(i) through a separation stage SC(i) as feed gas stream F2(i), F2(i) having the same chemical and physical composition and molar ratio x(R1(i))=x(F2(i)) as R1(i);

[0576] The separation stage SC(i) comprises

[0577] - passing the feed gas stream F2(i) through a second membrane unit M2(i) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0578] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at constant temperature, is greater than 1, obtaining

[0579] o a permeate gas stream P2(i) comprising H2; and

[0580] o A retentate gas stream R2(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(i)); x(R2(i)) <x(F2(i));

[0581] - removing the gas stream R2(i) from Z(i);

[0582] wherein, when i=1 ... n-1, the gas stream R2(i) is removed from Z(i) as a feed stream FS(i), FS(i) having the same chemical and physical composition and molar ratio x(R2(i))=x(FS(i)) as R2(i); and

[0583] wherein, when i=n, ​​the gas stream R2(n) is removed from Z(i) as a product gas stream;

[0584] The volume flow ratio of FS(i-1) to FS(i) is in the range of 1.05:1 to 4:1.

[0585] 2. The method as described in Example 1, wherein n=2 to 10, preferably n=2 to 5, more preferably n=2, 3 or 4, and more preferably n=2 or 3.

[0586] 3. The process according to embodiment 1 or 2, wherein, according to stage S(i), no vacuum device or compressor is operated downstream of the conversion reactor CR(i) according to SA(i) when obtaining the permeate gas stream and / or the retentate gas stream, preferably when obtaining any permeate gas stream and / or any retentate gas;

[0587] It is preferred that, according to all stages S(i) of the process, the stream or feed comprising hydrogen in the process is not compressed by a compressor or evacuated by a vacuum pump.

[0588] 4. A process as described in any of embodiments 1 to 3, wherein the feed gas stream FS(0) comprises, preferably consists of, NH3 having a purity in the range of 85 to 99.99998 wt.-%, preferably in the range of 95 to 99.998 wt.-%, more preferably in the range of 98 to 99.8 wt.-%, calculated based on the sum of all gas components present; wherein preferably in addition to NH3, the feed gas stream FS(0) also comprises impurities, wherein the impurities are preferably one or more of N2, O2, water, CO2, CO, CH4, H2, hydrocarbons and Ar, more preferably one or more of N2, O2 and water, more preferably one or more of N2 and water.

[0589] 5. A method as described in any one of Examples 1 to 4, wherein the feed gas flow FS(0) is obtained by a method selected from the group consisting of: a Haber-Bosch method, an electrochemical ammonia synthesis method, a non-thermal or thermal plasma-assisted ammonia production method, and a combination of two or more thereof, preferably obtained by the Haber-Bosch method or the electrochemical ammonia synthesis method.

[0590] 6. A method as described in any one of Examples 1 to 5, wherein, according to SA(i), the feed gas flow FS(i-1) is contacted with the conversion catalyst C(i) at a pressure in the range of 10 to 100 bar (absolute pressure), preferably in the range of 15 to 85 bar (absolute pressure), and more preferably in the range of 20 to 60 bar (absolute pressure).

[0591] 7. A method as described in any one of Examples 1 to 6, wherein, according to SA(i), the feed gas flow FS(i-1) is contacted with the conversion catalyst C(i) at a temperature in the range of 50°C to 1100°C, preferably in the range of 100°C to 1000°C, and more preferably in the range of 350°C to 900°C.

[0592] 8. The method of any one of embodiments 1 to 7, wherein the conversion catalyst C(i) comprises, preferably consists of, a transition metal supported on a refractory support material.

[0593] 9. A method as described in Example 8, wherein the transition metal is selected from the group consisting of Fe, Cu, Ni, Co, Ru, Ag, Pd, Rh, Pt, Ir, including combinations of two or more thereof, preferably selected from the group consisting of Ni, Co, Rh and Ru, including combinations of two or more thereof, more preferably Ni, Co or Ru, and even more preferably Ru.

[0594] 10. A method as described in Example 8 or 9, wherein the refractory carrier material is selected from the group consisting of: zeolite, alumina, silica, titania, zirconia, ceria, lanthanum oxide, praseodymium oxide, neodymium oxide, yttrium oxide, activated carbon, carbon nanotubes and a combination of two or more thereof, preferably selected from the group consisting of: alumina, silica, titania, zirconia and a combination of two or more thereof, more preferably alumina or zirconia.

[0595] 11. A method as described in any of Examples 8 to 10, wherein the transition metal catalyst supported on the refractory support material is preferably promoted with a metal selected from the group consisting of: lithium, sodium, potassium, cesium, lanthanum, yttrium, neodymium, praseodymium and combinations of two or more thereof, more preferably selected from the group consisting of: lithium, sodium, potassium, cesium and combinations of two or more thereof, more preferably the metal is potassium or cesium.

[0596] 12. The method of any one of embodiments 1 to 11, wherein the conversion catalyst C(i) is a molded article.

[0597] 13. A method as described in any of Examples 1 to 12, wherein at least 95 vol.-%, preferably 95 to 100 vol.-%, more preferably 98 to 100 vol.-%, more preferably 99 to 100 vol.-%, more preferably 99.5 to 100 vol.-% of the gas stream G(i) consists of NH3, N2 and H2.

[0598] 14. A method as described in any of Examples 1 to 13, wherein the gas stream G(i) has a molar ratio x(G(i)) of H2 to NH3 in the range of 0.01:1 to 500:1, preferably in the range of 0.05:1 to 200:1, and more preferably in the range of 2:1 to 50:1 (calculated as n(H2):n(NH3)=x(G(i))).

[0599] 15. A method as described in any one of Examples 1 to 14, wherein the gas flow G(i) has a molar ratio of H2 to N2 y(G(i)) in the range of 0.01:1 to 5:1 (calculated as n(H2):n(N2)=y(G(i))).

[0600] 16. A method as described in any of Examples 1 to 15, wherein the gas stream G(i) has a pressure in the range of 10 to 100 bar (absolute pressure), preferably in the range of 15 to 65 bar (absolute pressure), and more preferably in the range of 20 to 60 bar (absolute pressure).

[0601] 17. The method of any one of embodiments 1 to 16, wherein the gas stream G(i) has a temperature in the range of 50°C to 1100°C, preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C.

[0602] 18. A method as described in any of Examples 1 to 17, wherein the feed gas flow F1(i) is passed through a heat exchanger H(i) before passing through the separation stage SB(i); wherein the temperature of F1(i) leaving H(i) is preferably lower than the temperature of F1(i) entering H(i).

[0603] 19. A method as described in any one of Examples 1 to 18, wherein the feed gas flow F1(i) has a molar ratio of H2 to NH3 x(F1(i)) (calculated as n(H2):n(NH3)=x(F1(i))=x(G(i))) in the range of 0.01:1 to 500:1, preferably in the range of 0.05:1 to 200:1, and more preferably in the range of 2:1 to 50:1.

[0604] 20. A method as described in any one of Examples 1 to 19, wherein the feed gas stream F1(i) has a molar ratio of H2 to N2 y(F1(i)) in the range of 0.01:1 to 5:1 (calculated as n(H2):n(N2)=y(F1(i))=y(G(i))).

[0605] 21. The method of any one of embodiments 1 to 20, wherein the feed gas stream F1(i) has a pressure in the range of 10 to 100 bar (absolute pressure), preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure).

[0606] 22. A method as described in any of Examples 1 to 21, wherein the feed gas stream F1(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C, wherein the temperature is preferred after passing through H(i) as defined in Example 18.

[0607] 23. The method of any one of embodiments 1 to 22, wherein the volume flow ratio of FS(i-1) to (F1(i)) is in the range of 0.5:1 to 1:1, preferably in the range of 0.50:1 to 0.95:1.

[0608] 24. A method as described in any one of Examples 1 to 23, wherein, according to SB(i), the membrane unit M1(i) comprising at least one membrane has an H2 / NH3 selectivity of at least 2500, preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000; wherein, according to SB(i), the membrane unit M1(i) comprising at least one membrane preferably has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0609] 25. The method of any one of embodiments 1 to 24, wherein, according to SB(i), the at least one membrane included in the membrane unit M1(i) is a palladium metal membrane; wherein, preferably according to SB(i), the at least one membrane included in the membrane unit M1(i) has a Pd metal film of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0610] 26. The method of any one of embodiments 1 to 25, wherein, according to SB(i), the at least one membrane included in membrane unit M1(i) is a palladium metal membrane.

[0611] 27. A method as described in Example 26, wherein the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, preferably at least 98.5%, and more preferably in the range of 99.0% to 99.9%, wherein the substrate of the palladium metal film is preferably selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0612] 28. The method of embodiment 26, wherein the palladium metal film comprises an alloy coating on a substrate, the alloy coating comprising, more preferably consisting of: Pd and one or more of Ag, Au, Ru, In, Cu, and Y, more preferably Pd and one or more of Ag, Cu, and Y, more preferably Pd and Ag;

[0613] wherein preferably 0.50 wt.-% to 50 wt.-%, more preferably 1 wt.-% to 45 wt.-%, more preferably 3 wt.-% to 35 wt.-%, more preferably 7 wt.-% to 30 wt.-%, more preferably 8 wt.-% to 15 wt.-% of the alloy coating consists of metal other than palladium;

[0614] More preferably, the substrate of the palladium metal film is selected from the group consisting of steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0615] 29. The method of any one of embodiments 1 to 28, wherein according to SB(i), the pressure ratio calculated as (pressure of feed gas stream F1(i) / pressure of permeate gas stream P1(i)) at a constant temperature across the at least one membrane included in membrane unit M1(i) is It is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, and more preferably in the range of 2.5:1 to 35:1.

[0616] 30. The method of any one of embodiments 1 to 29, wherein, according to SB(i), the permeate gas stream P1(i) has a pressure in the range of 3 to 30 bar (absolute), preferably in the range of 5 to 20 bar (absolute), more preferably in the range of 5 to 15 bar (absolute).

[0617] 31. The method of any one of embodiments 1 to 30, wherein, according to SB(i), the permeate gas stream P1(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0618] 32. A method as described in any of Examples 1 to 31, wherein, according to SB(i), the permeate gas stream P1(i) further comprises NH3 and has a molar ratio of H2 to NH3 x(P1(i)) (calculated as n(H2):n(NH3)=x(P1(i))>x(F1(i))) greater than 500:1, more preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1,000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, and more preferably in the range of 20,000:1 to 60,000:1.

[0619] 33. The process of any one of embodiments 1 to 32, wherein, according to SB(i), the permeate gas stream P1(i) has a molar ratio of H2 to N2 y(P1(i)) (calculated as n(H2):n(N2)=y(P1(i)) greater than 500:1, preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, more preferably in the range of 20,000:1 to 60,000:1 <y(F1(i)))。

[0620] 34. A method as described in any of Examples 1 to 33, wherein, according to SB(i), the volume flow ratio of feed gas F1(i) to permeate gas flow P1(i) calculated as (volume flow F1(i) / volume flow P1(i)) is in the range of 1.5:1 to 50:1, preferably in the range of 2:1 to 40:1, and more preferably in the range of 3:1 to 30:1.

[0621] 35. The method of any one of embodiments 1 to 34, wherein, according to SB(i), the retentate gas stream R1(i) has a pressure in the range of 10 to 100 bar (absolute pressure), preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure).

[0622] 36. The method of any one of embodiments 1 to 35, wherein, according to SB(i), the retentate gas stream R1(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0623] 37. A method as described in any of Examples 1 to 36, wherein, according to SB(i), the retentate gas stream R1(i) has a molar ratio of H2 to NH3 x(R1(i)) (calculated as n(H2):n(NH3)=x(R1(i))=x(F2)) in the range of 0.1:1 to 100:1, preferably in the range of 0.5:1 to 60:1, and more preferably in the range of 1:1 to 10:1.

[0624] 38. A method as described in any of Examples 1 to 37, wherein, according to SB(i), the retentate gas stream R1(i) has a molar ratio of H2 to N2 y(R1(i)) in the range of 0.01:1 to 3:1, preferably in the range of 0.25:1 to 2:1 (calculated as n(H2):n(N2)=y(R1(i))=y(F2)).

[0625] 39. A method as described in any of Examples 1 to 38, wherein, according to SB(i), the volume flow ratio of the feed gas F1(i) to the retentate gas flow R1(i) calculated as (volume flow F1(i) / volume flow R1(i)) is in the range of 1:1 to 5:1, preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0626] 40. A method as described in any one of Examples 1 to 39, wherein, according to SB(i), the membrane unit M1(i) comprises two or more membranes, the membranes are connected in parallel and the feed gas flow F1(i) passes through the two or more membranes simultaneously, and the permeate gas flow P1(i) and the retentate gas flow R1(i) are obtained from the membranes simultaneously and in parallel.

[0627] 41. The method of any one of embodiments 1 to 40, wherein, according to SC(i), the feed gas stream F2(i) has a pressure in the range of 10 to 100 bar (absolute pressure), preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure).

[0628] 42. The method of any one of embodiments 1 to 41, wherein, according to SC(i), the feed gas stream F2(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0629] 43. A method as described in any of Examples 1 to 42, wherein, according to SC(i), the feed gas stream F2(i) has a molar ratio of H2 to NH3 x(F2(i)) (calculated as n(H2):n(NH3)=x(F2(i))=x(R1(i))) in the range of 0.1:1 to 100:1, preferably in the range of 0.5:1 to 60:1, and more preferably in the range of 1:1 to 10:1.

[0630] 44. A method as described in any of Examples 1 to 43, wherein, according to SC(i), the feed gas stream F2(i) has a molar ratio of H2 to N2 y(F2(i)) in the range of 0.01:1 to 3:1, more preferably in the range of 0.25:1 to 2:1 (calculated as n(H2):n(N2)=y(F2(i))=y(R1(i))).

[0631] 45. A method as described in any of Examples 1 to 44, wherein, according to SB(i) and SC(i), the volume flow ratio of F1(i) to R1(i) calculated as (volume flow F1(i) / volume flow R1(i)) is equal to the volume flow ratio of F1(i) to F2(i) calculated as (volume flow F1(i) / volume flow F2(i)), and is in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0632] 46. ​​A method as described in any of Examples 1 to 45, wherein, according to SC(i), the membrane unit M2(i) comprising at least one membrane has an H2 / NH3 selectivity of at least 2,500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000; wherein preferably, according to SC(i), the membrane unit M2(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0633] 47. A method as described in any one of embodiments 1 to 46, wherein, according to SC(i), the at least one membrane included in the membrane unit M2(i) is a palladium metal membrane; wherein, preferably according to SC(i), the at least one membrane included in the membrane unit M2(i) has a Pd metal film of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0634] 48. The method of any one of Embodiments 1 to 47, wherein, according to SC(i), the at least one membrane included in membrane unit M2(i) is a palladium metal membrane.

[0635] 49. A method as described in Example 48, wherein the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, preferably at least 98.5%, and more preferably in the range of 99.0% to 99.9%, wherein the substrate of the palladium metal film is preferably selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0636] 50. The method of embodiment 48, wherein the palladium metal film comprises an alloy coating on a substrate, the alloy coating comprising, preferably consisting of: Pd and one or more of Ag, Au, Ru, In, Cu and Y, more preferably Pd and one or more of Ag, Cu and Y, more preferably Pd and Ag;

[0637] Preferably, 0.50 wt.-% to 50 wt.-%, more preferably 1 wt.-% to 45 wt.-%, more preferably 3 wt.-% to 35 wt.-%, more preferably 7 wt.-% to 30 wt.-%, more preferably 8 wt.-% to 15 wt.-% of the alloy coating is composed of metals other than palladium, and more preferably the substrate of the palladium metal film is selected from the group consisting of steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0638] 51. A method as described in any of embodiments 1 to 50, wherein, according to SC(i), the pressure ratio across the at least one membrane included in the membrane unit M2(i) calculated as (pressure of the feed gas stream F2(i) / pressure of the permeate gas stream P2(i)) at a constant temperature is It is in the range of 1.5:1 to 50:1, preferably in the range of 2:1 to 40:1, and more preferably in the range of 2.5:1 to 35:1.

[0639] 52. The method of any one of embodiments 1 to 51, wherein, according to SC(i), the permeate gas stream P2(i) has a pressure in the range of 1.1 to 30 bar (absolute pressure), preferably in the range of 1.1 to 10 bar (absolute pressure), more preferably in the range of 1.1 to 2.5 bar (absolute pressure).

[0640] 53. The method of any one of embodiments 1 to 52, wherein, according to SC(i), the permeate gas stream P2(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0641] 54. A method as described in any of Examples 1 to 53, wherein, according to SC(i), the permeate gas stream P2(i) further comprises NH3 and has a molar ratio x(P2(i)) of H2 to NH3 greater than 500:1, preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, and more preferably in the range of 20,000:1 to 60,000:1.

[0642] 55. The process of any one of embodiments 1 to 54, wherein, according to SC(i), the permeate gas stream P2(i) further comprises H2 and has a molar ratio y(P2(i)) of H2 to N2 (calculated as n(H2):n(N2)=y(P2(i)) greater than 500:1, preferably in the range of 500:1 to 100,000:1, more preferably in the range of 1000:1 to 90,000:1, more preferably in the range of 15,000:1 to 80,000:1, more preferably in the range of 20,000:1 to 60,000:1 <y(F2(i)))。

[0643] 56. A method as described in any of Examples 1 to 55, wherein, according to SC(i), the volume flow ratio of feed gas F2(i) to permeate gas flow P2(i) calculated as (volume flow F2(i) / volume flow P2(i)) is in the range of 1.5:1 to 50:1, preferably in the range of 2:1 to 40:1, and more preferably in the range of 3:1 to 30:1.

[0644] 57. The method of any one of embodiments 1 to 56, wherein, according to SC(i), the retentate gas stream R2(i) has a pressure in the range of 10 to 100 bar (absolute), preferably in the range of 15 to 85 bar (absolute), more preferably in the range of 20 to 60 bar (absolute).

[0645] 58. The method of any one of embodiments 1 to 57, wherein, according to SC(i), the retentate gas stream R2(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0646] 59. A method as described in any of Examples 1 to 58, wherein, according to SC(i), the retentate gas stream R2(i) has a molar ratio of H2 to NH3 x(R2(i)) (calculated as n(H2):n(NH3)=x(R2(i))=x(FS(i))) in the range of 0.05:1 to 100:1, preferably in the range of 0.1:1 to 30:1, and more preferably in the range of 0.2:1 to 5:1.

[0647] 60. A method as described in any of Examples 1 to 59, wherein, according to SC(i), the retentate gas stream R2(i) has a molar ratio of H2 to N2 y(R2(i)) (calculated as n(H2):n(N2)=y(R2(i))=y(FS(i))) in the range of 0.01:1 to 2:1, preferably in the range of 0.03:1 to 2:1, and more preferably in the range of 0.05:1 to 1.5:1.

[0648] 61. A method as described in any of Examples 1 to 60, wherein, according to SC(i), the volume flow ratio of F2(i) to R2(i) calculated as (volume flow F2(i) / volume flow R2(i)) is in the range of 1:1 to 5:1, preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0649] 62. The process of any one of embodiments 1 to 61, wherein, according to SC(i), the feed stream FS(i) has a pressure in the range of 10 to 100 bar (absolute), more preferably in the range of 15 to 85 bar (absolute), more preferably in the range of 20 to 60 bar (absolute).

[0650] 63. The process of any one of embodiments 1 to 62, wherein, according to SC(i), the feed stream FS(i) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0651] 64. A method as described in any of Examples 1 to 63, wherein, according to SC(i), the feed stream FS(i) has a molar ratio of H2 to NH3 x(F2(i)) (calculated as n(H2):n(NH3)=x(FS(i))=x(R2(i))) in the range of 0.05:1 to 100:1, preferably in the range of 0.1:1 to 30:1, and more preferably in the range of 0.2:1 to 5:1.

[0652] 65. A method as described in any of Examples 1 to 64, wherein, according to SC(i), the feed stream FS(i) has a molar ratio of H2 to N2 y(FS(i)) (calculated as n(H2):n(N2)=y(FS(i))=y(R2(i))) in the range of 0.01:1 to 2:1, preferably in the range of 0.03:1 to 2:1, and more preferably in the range of 0.05:1 to 1.5:1.

[0653] 66. A method as described in any of Examples 1 to 65, wherein, according to SC(i), the volume flow ratio of F2(i) to R2(i) calculated as (volume flow F2(i) / volume flow R2(i)) is equal to the volume flow ratio of F2(i) to FS(i) calculated as (volume flow F2(i) / volume flow FS(i)), and is in the range of 1:1 to 5:1, preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0654] 67. The method of any one of embodiments 1 to 66, wherein, according to SC(n), the retentate gas stream R2(n) has a pressure in the range of 10 to 100 bar (absolute), preferably in the range of 15 to 85 bar (absolute), more preferably in the range of 20 to 60 bar (absolute).

[0655] 68. The method of any one of embodiments 1 to 67, wherein, according to SC(n), the retentate gas stream R2(n) has a temperature in the range of 250°C to 700°C, preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C.

[0656] 69. A method as described in any of Examples 1 to 68, wherein, according to SC(n), the retentate gas stream R2(n) has a molar ratio of H2 to NH3 x(R2(i)) (calculated as n(H2):n(NH3)=x(R2(n))) in the range of 0.05:1 to 100:1, preferably in the range of 0.1:1 to 30:1, and more preferably in the range of 0.2:1 to 5:1.

[0657] 70. A method as described in any of Examples 1 to 69, wherein, according to SC(n), the retentate gas stream R2(n) has a molar ratio of H2 to N2 y(R2(i)) (calculated as n(H2):n(N2)=y(R2(n))) in the range of 0.01:1 to 2:1, preferably in the range of 0.03:1 to 2:1, and more preferably in the range of 0.05:1 to 1.5:1.

[0658] 71. A method as described in any of Examples 1 to 70, wherein, according to SC(n), the volume flow ratio of F2(n) to R2(n) calculated as (volume flow F2(n) / volume flow R2(n)) is in the range of 1:1 to 5:1, preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:1.

[0659] 72. A method as described in any one of Examples 1 to 71, wherein, according to SC(i), the membrane unit M2(i) comprises two or more membranes, the membranes are connected in parallel and the feed gas flow F2(i) passes through the two or more membranes simultaneously, and the permeate gas flow P2(i) and the retentate gas flow R2(i) are obtained from the membranes simultaneously and in parallel.

[0660] 73. The method of any one of embodiments 1 to 72, wherein the volume flow ratio of FS(i-1) to (FS(i)) is in the range of 1.1:1 to 3:1, preferably in the range of 1.2:1 to 2.5:1.

[0661] 74. The method of any one of Examples 1 to 73, wherein the ratio of the pressure of the permeate gas stream P1(i) to the permeate gas stream P2(i) is in the range of 50:1 to 1.5:1, more preferably in the range of 20:1 to 2:1, more preferably in the range of 15:1 to 3:1, more preferably in the range of 12:1 to 4:1.

[0662] 75. A method as described in any one of Examples 1 to 74, wherein the volume flow ratio of FS(n-1) to R2(n) is in the range of 1.05:1 to 4:1, preferably in the range of 1.1 to 3, and more preferably in the range of 1.5 to 2.5.

[0663] 76. The process of any one of embodiments 1 to 75, wherein n=2, the apparatus for recovering H2 from converted NH3 comprises two zones Z(1) and Z(2) connected in series,

[0664] Among them, zone Z(1) includes

[0665] a conversion reactor CR (1) comprising a catalyst C (1) for converting NH3 to give H2,

[0666] - the first membrane unit M1 (1) and

[0667] - a second membrane unit M2 (1),

[0668] wherein in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1), and

[0669] Among them, zone Z(2) includes

[0670] a conversion reactor CR (2) comprising a catalyst C (2) for converting NH 3 to give H 2 ,

[0671] - first membrane unit M1(2) and

[0672] - a second membrane unit M2 (2),

[0673] wherein in Z(2), CR(2) is located upstream of M1(2) and M2(2) is located downstream of M1(2), wherein Z(1) is the most upstream zone and Z(2) is the most downstream zone,

[0674] The method includes

[0675] (a) providing a feed stream FS(0) comprising NH3;

[0676] (b) Two consecutive processing stages S(1) and S(2)

[0677] Where S(1) includes

[0678] The conversion phase SA (1) includes

[0679] - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(1) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(1) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0680] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0681] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0682] The separation stage SB (1) comprises

[0683] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0684] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0685] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(1) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0686] o a permeate gas stream P1(1) comprising H2; and

[0687] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0688] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0689] The separation stage SC (1) comprises

[0690] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(1) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0691] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0692] o a permeate gas stream P2(1) comprising H2; and

[0693] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0694] - removing the gas stream R2(1) from Z(1);

[0695] wherein the gas stream R2(1) is removed as a feed stream FS(1) having the same chemical and physical composition and molar ratio x(R2(1))=x(FS(1)) as R2(1); and

[0696] Where S(2) includes

[0697] The conversion phase SA (2) includes

[0698] - feeding a gas stream FS(1) into a conversion reactor CR(2) comprised in Z(2) and contacting said stream FS(1) with C(2) in CR(2) to obtain a gas stream G(2) comprising NH3, N2 and H2, said gas stream G(2) having a molar ratio n(H2):n(NH3)=x(G(2));

[0699] - removing the gas stream G(2) comprising NH3, N2 and H2 from CR(2);

[0700] - passing this gas stream G(2) as feed gas stream F1(2) through a separation stage SB(2), F1(2) having the same chemical composition as G(2) and the molar ratio x(G(2))=x(F1(2));

[0701] The separation stage SB (2) comprises

[0702] - passing the feed gas stream F1(2) through a first membrane unit M1(2) comprising at least one membrane of Z(2) at a pressure ratio φ,

[0703] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0704] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(2) / pressure of the permeate gas stream P1(2)) at constant temperature, is greater than 1, obtaining

[0705] o a permeate gas stream P1 (2) comprising H2; and

[0706] o A retentate gas stream R1(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(2)); x(R1(2)) <x(F1(2));

[0707] - passing the retentate gas stream R1(2) through a separation stage SC(2) as feed gas stream F2(2), F2(2) having the same chemical and physical composition as R1(2) and the molar ratio x(R1(2))=x(F2(2));

[0708] The separation stage SC (2) comprises

[0709] - passing the feed gas stream F2(2) through a second membrane unit M2(2) of Z(2) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0710] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(2) / pressure of the permeate gas stream P2(2)) at constant temperature, is greater than 1, obtaining

[0711] o a permeate gas stream P2(2) comprising H2; and

[0712] o A retentate gas stream R2(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(2)); x(R2(2)) <x(F2(2));

[0713] - removing the gas flow R2(2) from Z(2);

[0714] wherein the gas stream R2(2) is removed as a product gas stream;

[0715] wherein the volume flow ratio of FS(0) to FS(1) is in the range of 1.05:1 to 4:1;

[0716] Preferably, the volume flow ratio of FS (1) to R2 (2) is in the range of 1.05:1 to 4:1.

[0717] 77. The process of any one of embodiments 1 to 76, wherein n=3, the apparatus for recovering H2 from converted NH3 comprises three zones Z(1), Z(2) and Z(3) connected in series,

[0718] Among them, zone Z(1) includes

[0719] a conversion reactor CR (1) comprising a catalyst C (1) for converting NH3 to give H2,

[0720] - the first membrane unit M1 (1) and

[0721] - a second membrane unit M2 (1),

[0722] where in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1),

[0723] Among them, zone Z(2) includes

[0724] a conversion reactor CR (2) comprising a catalyst C (2) for converting NH 3 to give H 2 ,

[0725] - first membrane unit M1(2) and

[0726] - a second membrane unit M2 (2),

[0727] wherein in Z(2), CR(2) is located upstream of M1(2) and M2(2) is located downstream of M1(2), and

[0728] Among them, zone Z(3) includes

[0729] a conversion reactor CR (3) comprising a catalyst C (3) for converting NH3 to give H2,

[0730] - first membrane unit M1 (3) and

[0731] - a second membrane unit M2 (3),

[0732] wherein in Z(3), CR(3) is located upstream of M1(3) and M2(3) is located downstream of M1(3), wherein Z(1) is the most upstream zone, Z(3) is the most downstream zone, Z(2) is downstream of Z(1) and upstream of Z(3),

[0733] The method includes

[0734] (a) providing a feed gas stream FS(0) comprising NH3;

[0735] (b) Three consecutive processing stages S(1), S(2) and S(3)

[0736] Where S(1) includes

[0737] The conversion phase SA (1) includes

[0738] - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(1) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(1) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0739] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0740] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0741] The separation stage SB (1) comprises

[0742] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0743] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0744] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(1) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0745] o a permeate gas stream P1(1) comprising H2; and

[0746] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0747] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0748] The separation stage SC (1) comprises

[0749] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(1) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0750] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0751] o a permeate gas stream P2(1) comprising H2; and

[0752] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0753] - removing the gas stream R2(1) from Z(1);

[0754] wherein the gas stream R2(1) is removed as a feed stream FS(1) having the same chemical and physical composition and molar ratio x(R2(1))=x(FS(1)) as R2(1); and

[0755] Where S(2) includes

[0756] The conversion phase SA (2) includes

[0757] - feeding a gas stream FS(1) into a conversion reactor CR(2) comprised in Z(2) and contacting said stream FS(1) with C(2) in CR(2) to obtain a gas stream G(2) comprising NH3, N2 and H2, said gas stream G(2) having a molar ratio n(H2):n(NH3)=x(G(2));

[0758] - removing the gas stream G(2) comprising NH3, N2 and H2 from CR(2);

[0759] - passing this gas stream G(2) as feed gas stream F1(2) through a separation stage SB(2), F1(2) having the same chemical composition as G(2) and the molar ratio x(G(2))=x(F1(2));

[0760] The separation stage SB (2) comprises

[0761] - passing the feed gas stream F1(2) through a first membrane unit M1(2) comprising at least one membrane of Z(2) at a pressure ratio φ,

[0762] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0763] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(2) / pressure of the permeate gas stream P1(2)) at constant temperature, is greater than 1, obtaining

[0764] o a permeate gas stream P1 (2) comprising H2; and

[0765] o A retentate gas stream R1(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(2)); x(R1(2)) <x(F1(2));

[0766] - passing the retentate gas stream R1(2) through a separation stage SC(2) as feed gas stream F2(2), F2(2) having the same chemical and physical composition as R1(2) and the molar ratio x(R1(2))=x(F2(2));

[0767] The separation stage SC (2) comprises

[0768] - passing the feed gas stream F2(2) through a second membrane unit M2(2) of Z(2) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0769] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(2) / pressure of the permeate gas stream P2(2)) at constant temperature, is greater than 1, obtaining

[0770] o a permeate gas stream P2(2) comprising H2; and

[0771] o A retentate gas stream R2(2) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(2)); x(R2(2)) <x(F2(2));

[0772] - removing the gas flow R2(2) from Z(2);

[0773] wherein a gas stream R2(2) is removed as a feed stream FS(2), FS(2) having the same chemical and physical composition and molar ratio x(R2(2))=x(FS(2)) as R2(2); and

[0774] Where S(3) includes

[0775] The conversion phase SA (3) includes

[0776] - feeding a gas stream FS(2) into a conversion reactor CR(3) comprised in Z(3) and contacting said stream FS(2) with C(3) in CR(3) to obtain a gas stream G(3) comprising NH3, N2 and H2, said gas stream G(3) having a molar ratio n(H2):n(NH3)=x(G(3));

[0777] - removing the gas stream G (3) comprising NH3, N2 and H2 from CR (3);

[0778] - passing this gas stream G(3) as feed gas stream F1(3) through a separation stage SB(3), F1(3) having the same chemical composition as G(3) and the molar ratio x(G(3))=x(F1(3));

[0779] The separation stage SB (3) comprises

[0780] - passing the feed gas stream F1 (3) through a first membrane unit M1 (3) comprising at least one membrane of Z(3) at a pressure ratio φ,

[0781] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0782] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1 (3) / pressure of the permeate gas stream P1 (3)) at constant temperature, is greater than 1, obtaining

[0783] o a permeate gas stream P1 (3) comprising H2; and

[0784] o A retentate gas stream R1(3) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(3)); x(R1(3)) <x(F1(3));

[0785] - passing the retentate gas stream R1(3) through a separation stage SC(3) as feed gas stream F2(3), F2(3) having the same chemical and physical composition as R1(3) and the molar ratio x(R1(3))=x(F2(3));

[0786] The separation stage SC (3) comprises

[0787] - passing the feed gas stream F2(3) through a second membrane unit M2(3) of Z(3) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0788] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(3) / pressure of the permeate gas stream P2(3)) at constant temperature, is greater than 1, obtaining

[0789] o a permeate gas stream P2 (3) comprising H2; and

[0790] o A retentate gas stream R2(3) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(3)); x(R2(3)) <x(F2(3));

[0791] - removing the gas flow R2(3) from Z(3);

[0792] wherein the gas stream R2(3) is removed as a product gas stream;

[0793] wherein the volume flow ratio of FS(0) to FS(1) is in the range of 1.05:1 to 4:1, wherein the volume flow ratio of FS(1) to FS(2) is in the range of 1.05:1 to 4:1;

[0794] Preferably, the volume flow ratio of FS (1) to R2 (2) is in the range of 1.05:1 to 4:1.

[0795] 78. A method for recovering H2 from the conversion of NH3 in a plant comprising a zone Z(1) comprising a conversion reactor CR(1) comprising a catalyst C(1) for converting NH3 to give H2, a first membrane unit M1(1) and a second membrane unit M2(1),

[0796] where in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1),

[0797] The method includes

[0798] (a) providing a feed gas stream FS(0) comprising NH3;

[0799] (b) Processing stage S(1)

[0800] Where S(1) includes

[0801] The conversion phase SA (1) includes

[0802] - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(i) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1));

[0803] - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1);

[0804] - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1));

[0805] The separation stage SB (1) comprises

[0806] - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ,

[0807] The at least one membrane has a H2 / NH3 selectivity of at least 2000,

[0808] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F1(i) / pressure of the permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining

[0809] o a permeate gas stream P1(1) comprising H2; and

[0810] o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1));

[0811] - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1));

[0812] The separation stage SC (1) comprises

[0813] - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ,

[0814] The pressure ratio across the at least one membrane, calculated as (pressure of the feed gas stream F2(1) / pressure of the permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining

[0815] o a permeate gas stream P2(1) comprising H2; and

[0816] o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1));

[0817] - removing the gas stream R2(1) from Z(1);

[0818] wherein the gas stream R2(1) is removed from Z(1) as a product gas stream;

[0819] The volume flow ratio of FS(0) to R2(1) is in the range of 1.05:1 to 4:1.

[0820] 79. The method of embodiment 78, having ranges and parameters defined for an alternative having two or more zones according to embodiments 1 to 77.

[0821] 80. A device for recovering H2 from converting NH3, the device comprising

[0822] n zones Z(i), where i=1…n, where n≥1,

[0823] wherein, when n≥2, the n zones Z(i) are connected in series and Z(1) is the most upstream zone and Z(n) is the most downstream zone,

[0824] Each zone Z(i) includes

[0825] The conversion reactor unit U.CR(i) comprises

[0826] - a supply device for supplying a feed stream FS(i-1) comprising NH 3 to the conversion reactor CR(i);

[0827] a conversion reactor CR(i) for converting NH3 into a gas stream G(i) comprising NH3, N2 and H2, the conversion reactor CR(i) comprising a conversion catalyst C(i);

[0828] - outlet means for removing the gas stream G(i) as feed gas stream F1(i) from CR(i) to the membrane separation unit U.M1(i);

[0829] The first membrane separation unit U.M1(i) comprises

[0830] - means for sending the feed gas stream F1(i) to the first membrane unit M1(i);

[0831] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0832] - outlet means for removing the permeate gas stream P1 (i) from the membrane unit M1 (i);

[0833] - outlet means for removing a retentate gas stream R1 (i) from the membrane unit M1 (i);

[0834] The second membrane separation unit U.M2(i) comprises

[0835] - means for feeding the retentate gas stream R1(i) as feed gas stream F2(i) to the second membrane unit M2(i);

[0836] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0837] - outlet means for removing the permeate gas stream P2(i) from the membrane unit M2(i);

[0838] outlet means for removing a retentate gas stream R2(i) from Z(i); and,

[0839] means for sending R2(i) removed from Z(i) as feed stream FS(i) to Z(i+1) when n≥2 and i≠n;

[0840] In Z(i), U.CR(i) is located upstream of U.M1(i) and U.M2(i) is located downstream of U.M1(i).

[0841] 81. The apparatus of embodiment 80, wherein n=1 to 10, preferably n=1 to 5, more preferably n=1, 2, 3 or 4, more preferably n=1 or 2 or 3.

[0842] 82. An apparatus as described in Example 80 or 81, wherein no vacuum device or compressor is arranged downstream of the conversion reactor CR(i) according to U.CR(i); preferably, wherein the feed gas, permeate flow and / or retentate flow used to carry hydrogen do not have a compressor or vacuum device connected to or operating with any unit of the apparatus.

[0843] 83. An apparatus as described in any of Examples 80 to 82, wherein the conversion reactor unit U.CR(i) includes a heating device for heating the conversion reactor CR(i) to a temperature in the range of 50°C to 1100°C, preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C.

[0844] 84. The apparatus of any one of embodiments 80 to 83, wherein the conversion catalyst C(i) comprises, preferably consists of, a transition metal supported on a refractory support material.

[0845] 85. An apparatus as described in Example 84, wherein the transition metal is selected from the group consisting of Fe, Cu, Ni, Co, Ru, Ag, Pd, Rh, Pt, Ir, including combinations of two or more thereof, preferably selected from the group consisting of Ni, Co, Rh and Ru, including combinations of two or more thereof, more preferably Ni, Co or Ru, and even more preferably Ru.

[0846] 86. An apparatus as described in Example 84 or 85, wherein the refractory carrier material is selected from the group consisting of: zeolite, alumina, silica, titania, zirconia, cerium dioxide, lanthanum oxide, praseodymium oxide, neodymium oxide, yttrium oxide, activated carbon, carbon nanotubes and a combination of two or more thereof, preferably selected from the group consisting of: alumina, silica, titania, zirconia and a combination of two or more thereof, more preferably alumina or zirconia.

[0847] 87. An apparatus as described in any of Examples 84 to 86, wherein the transition metal catalyst supported on the refractory support material is preferably promoted with a metal selected from the group consisting of lithium, sodium, potassium, cesium, lanthanum, yttrium, neodymium, praseodymium and combinations of two or more thereof, more preferably selected from the group consisting of lithium, sodium, potassium, cesium and combinations of two or more thereof, more preferably potassium or cesium.

[0848] 88. The apparatus of any one of embodiments 80 to 87, wherein the conversion catalyst C(i) is a molded article.

[0849] 89. An apparatus as described in any of Examples 80 to 88, wherein the conversion reactor unit U.CR(i) includes a heat exchange device H(i), which is arranged downstream of the outlet device for removing the gas flow G(i) from CR(i) and upstream of the device for sending the feed gas flow F1(i) to the first membrane unit M1(i).

[0850] 90. An apparatus as described in any of Examples 80 to 89, wherein the conversion reactor unit U.CR(i) includes a heat exchange device H(i) for adjusting the temperature of the feed gas flow F1(i) to a range of 250°C to 700°C, preferably to a range of 300°C to 600°C, and more preferably to a range of 350°C to 500°C.

[0851] 91. The apparatus of any one of embodiments 80 to 90, wherein the membrane unit M1(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2,500, preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5000 to 800,000, more preferably in the range of 6000 to 600,000;

[0852] Preferably, the membrane unit M1(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0853] 92. The apparatus of any one of embodiments 80 to 91, wherein the at least one membrane included in the membrane unit M1(i) is a palladium metal membrane; wherein preferably, the at least one membrane included in the membrane unit M1(i) has a relative humidity of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0854] 93. The method of any one of Embodiments 80 to 92, wherein the at least one membrane included in membrane unit M1 (i) is a palladium metal membrane.

[0855] 94. A method as described in Example 93, wherein the palladium metal film comprises a palladium coating on a substrate, the palladium coating consisting of palladium having a purity of at least 97.5%, preferably at least 98.5%, and more preferably in the range of 99.0% to 99.9%, wherein the substrate of the palladium metal film is preferably selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0856] 95. The method of embodiment 93, wherein the palladium metal film comprises an alloy coating on a substrate, the alloy coating comprising, preferably consisting of: Pd and one or more of Ag, Au, Ru, In, Cu, and Y, more preferably Pd and one or more of Ag, Cu, and Y, more preferably Pd and Ag;

[0857] Preferably, 0.50 wt.-% to 50 wt.-%, more preferably 1 wt.-% to 45 wt.-%, more preferably 3 wt.-% to 35 wt.-%, more preferably 7 wt.-% to 30 wt.-%, more preferably 8 wt.-% to 15 wt.-% of the alloy coating is composed of metals other than palladium, and more preferably the substrate of the palladium metal film is selected from the group consisting of steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0858] 96. An apparatus as described in any of Examples 80 to 95, wherein the membrane unit M1(i) comprises two or more membranes, which are connected in parallel to a device for sending a feed gas flow F1(i) to the first membrane unit M1(i), and are connected in parallel to an outlet device for removing a permeate gas flow P1(i) from the first membrane unit M1(i), and are connected in parallel to an outlet device for removing a retentate gas flow R1(i) from the first membrane unit M1(i).

[0859] 97. The apparatus of any one of embodiments 80 to 96, wherein the membrane unit M2(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2500, more preferably in the range of 2500 to 1,000,000, more preferably in the range of 4500 to 900,000, more preferably in the range of 5000 to 800,000, more preferably in the range of 6000 to 600,000;

[0860] Preferably, the membrane unit M2(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:1.

[0861] 98. The apparatus of any one of embodiments 80 to 97, wherein the at least one membrane included in the membrane unit M2(i) is a palladium metal membrane; wherein preferably, the at least one membrane included in the membrane unit M2(i) has a relative humidity of 0.1 to 100 Nm 3 / (m 2 h bar), more preferably in the range of 0.5 to 75 Nm 3 / (m 2 h bar), more preferably in the range of 1 to 50 Nm 3 / (m 2 h bar), more preferably in the range of 2 to 40 Nm 3 / (m 2 h bar), more preferably in the range of 3 to 30 Nm 3 / (m 2 h bar), more preferably in the range of 4 to 20 Nm 3 / (m 2 h bar), more preferably in the range of 5 to 10 Nm 3 / (m 2 h bar) range.

[0862] 99. The method of any one of Embodiments 80 to 98, wherein the at least one membrane included in membrane unit M2(i) is a palladium metal membrane.

[0863] 100. A method as described in Example 99, wherein the palladium metal film comprises a palladium coating on a substrate, the palladium coating being composed of palladium having a purity of at least 97.5%, preferably at least 98.5%, and more preferably in the range of 99.0% to 99.9%, wherein the substrate of the palladium metal film is preferably selected from the group consisting of: steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0864] 101. The method of embodiment 99, wherein the palladium metal film comprises an alloy coating on a substrate, the alloy coating comprising, preferably consisting of: Pd and one or more of Ag, Au, Ru, In, Cu, and Y, more preferably Pd and one or more of Ag, Cu, and Y, more preferably Pd and Ag;

[0865] Preferably, 0.50 wt.-% to 50 wt.-%, more preferably 1 wt.-% to 45 wt.-%, more preferably 3 wt.-% to 35 wt.-%, more preferably 7 wt.-% to 30 wt.-%, more preferably 8 wt.-% to 15 wt.-% of the alloy coating consists of metals other than palladium, wherein the substrate of the palladium metal film is preferably selected from the group consisting of steel, stainless steel, borosilicate glass, aluminum oxide and zirconium oxide.

[0866] 102. An apparatus as described in any of Examples 80 to 101, wherein the membrane unit M2(i) comprises two or more membranes, which are connected in parallel to a device for sending a feed gas flow F2(i) to a second membrane unit M1(i), and are connected in parallel to an outlet device for removing a permeate gas flow P2(i) from the second membrane unit M2(i), and are connected in parallel to an outlet device for removing a retentate gas flow R2(i) from the second membrane unit M2(i).

[0867] 103. The apparatus of any one of embodiments 80 to 102, wherein n=2, the apparatus comprises 2 zones Z(1) and Z(2) connected in series, wherein Z(1) is the most upstream zone and Z(2) is the most downstream zone,

[0868] Among them, zone Z(1) includes

[0869] The conversion reactor unit U.CR (1) comprises

[0870] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0871] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0872] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0873] The first membrane separation unit U.M1 (1) comprises

[0874] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0875] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0876] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0877] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0878] The second membrane separation unit U.M2(1) comprises

[0879] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0880] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0881] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0882] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0883] means for passing R2(1) removed from Z(1) as feed stream FS(1) to Z(2),

[0884] where in Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1),

[0885] Among them, zone Z(2) includes

[0886] The conversion reactor unit U.CR (2) comprises

[0887] - a supply device for supplying a feed stream FS (1) comprising NH 3 to the conversion reactor CR (2);

[0888] a conversion reactor CR (2) for converting NH3 into a gas stream G (2) comprising NH3, N2 and H2, the conversion reactor CR (2) comprising a conversion catalyst C (2);

[0889] - outlet means for removing the gas stream G(2) as feed gas stream F1(2) from CR(2) to the membrane separation unit U.M1(2);

[0890] The first membrane separation unit U.M1 (2) comprises

[0891] - means for sending the feed gas stream F1 (2) to the first membrane unit M1 (2);

[0892] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0893] - outlet means for removing the permeate gas stream P1 (2) from the membrane unit M1 (2);

[0894] - outlet means for removing the retentate gas stream R1 (2) from the membrane unit M1 (2);

[0895] The second membrane separation unit U.M2(2) comprises

[0896] - means for feeding the retentate gas stream R1 (2) as feed gas stream F2 (2) to the second membrane unit M2 (2);

[0897] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0898] - outlet means for removing the permeate gas stream P2(2) from the membrane unit M2(2);

[0899] outlet means for removing the retentate gas stream R2(2) from Z(2),

[0900] In Z(2), U.CR(2) is located upstream of U.M1(2) and U.M2(2) is located downstream of U.M1(2).

[0901] 104. The apparatus of any one of embodiments 80 to 103, wherein the apparatus comprises three zones Z(1), Z(2) and Z(3) connected in series,

[0902] Among them, Z(1) is the most upstream zone, and Z(3) is the most downstream zone.

[0903] Among them, zone Z(1) includes

[0904] The conversion reactor unit U.CR (1) comprises

[0905] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0906] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0907] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0908] The first membrane separation unit U.M1 (1) comprises

[0909] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0910] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0911] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0912] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0913] The second membrane separation unit U.M2(1) comprises

[0914] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0915] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0916] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0917] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0918] means for passing R2(1) removed from Z(1) as feed stream FS(1) to Z(2),

[0919] where in Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1),

[0920] Among them, zone Z(2) includes

[0921] The conversion reactor unit U.CR (2) comprises

[0922] - a supply device for supplying a feed stream FS (1) comprising NH 3 to the conversion reactor CR (2);

[0923] a conversion reactor CR (2) for converting NH3 into a gas stream G (2) comprising NH3, N2 and H2, the conversion reactor CR (2) comprising a conversion catalyst C (2);

[0924] - outlet means for removing the gas stream G(2) as feed gas stream F1(2) from CR(2) to the membrane separation unit U.M1(2);

[0925] The first membrane separation unit U.M1 (2) comprises

[0926] - means for sending the feed gas stream F1 (2) to the first membrane unit M1 (2);

[0927] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0928] - outlet means for removing the permeate gas stream P1 (2) from the membrane unit M1 (2);

[0929] - outlet means for removing the retentate gas stream R1 (2) from the membrane unit M1 (2);

[0930] The second membrane separation unit U.M2(2) comprises

[0931] - means for feeding the retentate gas stream R1 (2) as feed gas stream F2 (2) to the second membrane unit M2 (2);

[0932] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0933] - outlet means for removing the permeate gas stream P2(2) from the membrane unit M2(2);

[0934] outlet means for removing a retentate gas stream R2(2) from Z(2);

[0935] means for passing R2(2) removed from Z(2) as feed stream FS(2) to Z(3),

[0936] wherein in Z(2), U.CR(2) is located upstream of U.M1(2) and U.M2(2) is located downstream of U.M1(2);

[0937] Among them, zone Z(3) includes

[0938] The conversion reactor unit U.CR (3) comprises

[0939] - a supply device for supplying a feed stream FS (2) comprising NH 3 to the conversion reactor CR (3);

[0940] a conversion reactor CR (3) for converting NH3 into a gas stream G (3) comprising NH3, N2 and H2, the conversion reactor CR (3) comprising a conversion catalyst C (3);

[0941] - outlet means for removing the gas stream G(3) as feed gas stream F1(3) from CR(3) to the membrane separation unit U.M1(3);

[0942] The first membrane separation unit U.M1 (3) comprises

[0943] - means for sending the feed gas stream F1 (3) to the first membrane unit M1 (3);

[0944] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0945] - outlet means for removing the permeate gas stream P1 (3) from the membrane unit M1 (3);

[0946] - outlet means for removing the retentate gas stream R1 (3) from the membrane unit M1 (3);

[0947] The second membrane separation unit U.M2 (3) comprises

[0948] - means for feeding the retentate gas stream R1 (3) as feed gas stream F2 (3) to the second membrane unit M2 (3);

[0949] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0950] - outlet means for removing the permeate gas stream P2 (3) from the membrane unit M2 (3);

[0951] An outlet device for removing the retentate gas stream R2(3) from Z(3), wherein in Z(3) U.CR(3) is located upstream of U.M1(3) and U.M2(3) is located downstream of U.M1(3).

[0952] 105. The apparatus of any one of embodiments 80 to 104, wherein the apparatus comprises a single zone Z(1), wherein Z(1) comprises

[0953] The conversion reactor unit U.CR (1) comprises

[0954] - a supply device for supplying a feed stream FS (0) comprising NH 3 to the conversion reactor CR (1);

[0955] a conversion reactor CR(1) for converting NH3 into a gas stream G(1) comprising NH3, N2 and H2, the conversion reactor CR(1) comprising a conversion catalyst C(1);

[0956] - outlet means for removing the gas stream G(1) as feed gas stream F1(1) from CR(1) to the membrane separation unit U.M1(1);

[0957] The first membrane separation unit U.M1 (1) comprises

[0958] - means for sending the feed gas stream F1 (1) to the first membrane unit M1 (1);

[0959] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0960] - outlet means for removing the permeate gas stream P1 ( 1 ) from the membrane unit M1 ( 1 );

[0961] - outlet means for removing the retentate gas stream R1 ( 1 ) from the membrane unit M1 ( 1 );

[0962] The second membrane separation unit U.M2(1) comprises

[0963] - means for feeding the retentate gas stream R1 ( 1 ) as feed gas stream F2 ( 1 ) to the second membrane unit M2 ( 1 );

[0964] - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000;

[0965] - outlet means for removing the permeate gas stream P2(1) from the membrane unit M2(1);

[0966] outlet means for removing a retentate gas stream R2(1) from Z(1);

[0967] In Z(1), U.CR(1) is located upstream of U.M1(1) and U.M2(1) is located downstream of U.M1(1).

[0968] 106. The apparatus of any one of embodiments 80 to 105 for recovering H2 from converting NH3 according to the method of any one of embodiments 1 to 79.

[0969] 107. The apparatus of any one of embodiments 80 to 106, which does not include an ammonia condenser and / or does not include a gas-liquid phase separator, more preferably does not include an ammonia condenser and does not include a gas-liquid phase separator.

[0970] 108. A method as described in any one of Examples 1 to 79, wherein none of the n continuous processing stages S(i) includes the use of an ammonia condenser and / or the use of a gas-liquid phase separator, preferably none of the n continuous processing stages S(i) includes the use of an ammonia condenser and none of the n continuous processing stages S(i) includes the use of a gas-liquid phase separator.

[0971] 109. Use of the apparatus according to any one of embodiments 80 to 107 in a method for recovering H2 from converting NH3.

[0972] In the context of the present invention, it should be noted that the selectivity α, also called the ideal selectivity, is i,j is defined as the ratio of the permeabilities of components i and j. A detailed discussion on selectivity is given in Reference Example 1 below.

[0973] The following examples further illustrate the present invention.

[0974] Examples

[0975] Reference Example 1 Simulation Conditions

[0976] The performance of the decomposition reaction and membrane stage were simulated using MATLAB (R2020b version). The reactor was simulated using the isothermal equilibrium method. The equilibrium concentration at the reactor outlet was estimated based on the inlet concentrations (NH3, H2, and N2), reaction temperature, and reaction pressure. The required parameters for the calculations were taken from the NIST Chemistry WebBook (NIST Standard Reference Database No. 69).

[0977] Modeling of the membrane separation stage was performed using the general equation for hydrogen permeation through palladium membranes (S. Yun and S. Ted Oyama, "Correlations in palladium membranes for hydrogen separation: A review," Journal of Membrane Science, Vol. 375, No. 1-2, pp. 28-45, June 2011, doi: 10.1016 / j.memsci.2011.03.057.). Hydrogen permeation through palladium membranes follows a solution diffusion mechanism, described by the following equation:

[0978]

[0979] J i is the flux of component i, N i is the permeability of component I, P i is the permeability of component i, L is the thickness of the membrane layer, p i,h is the partial pressure of component i on the high pressure side, p i,l is the partial pressure of component i on the low pressure side, and m is the pressure exponent, usually in the range of 0.5-1.

[0980] In the case of hydrogen permeability through palladium-based membranes, bulk diffusion (4) is the rate-controlling step and for the simulations, m is assumed to be 0.5. For the simulations, the permeability of hydrogen, P H2 / L was taken from the literature and assumed to be 1.5×10 -6 mol s -1 m -2 Pa.

[0981] To obtain a unit match in the flux equation above, the units showing permeability should be in Nm 3 / (m 2 h bar^n). However, it is common in the literature to simply display the value as Nm 3 / (m 2h bar) (see the references by S. Yun and S. Ted Oyama above). Thus, the skilled person recognizes that the units of permeability, and in particular the exponent of the pressure units of permeability, should be changed accordingly to the value of n determined for the particular system.

[0982] Based on the flux equation, a CSTR (continuous stirred tank reactor) cascade model was established, which consists of 1000 unit cells. The following assumptions were made for the simulation of the membrane stage:

[0983] ●Isothermal conditions (T 入 =T 出 ),

[0984] ●The H2 partial pressure on the permeate side is equal to the absolute pressure,

[0985] ● Compared with the absolute pressure, the retentate pressure loss is small and is negligible,

[0986] The volume of gas obtained from the reactor is processed to have a desired gas composition, and the volume flow rate increases in proportion to the increase in gas molecules,

[0987] ● Treat the membrane to be ideal and infinitely selective

[0988] ● Separation of H2 into pure hydrogen in the permeate.

[0989] Based on the flowchart shown ( Figure 1 and Figure 2 ), two different inventive scenarios were calculated. Each stage according to the invention consists of a reactor CR(i), a high-pressure permeable membrane M1(i) and a low-pressure permeable membrane M2(i) all connected in series. For the reference case simulation, one stage consists only of a reactor CR(i) and a membrane separation module. NH3 = 1) is used as feed FS(0) to the first reactor CR(1). For all simulations, the flow rate of the feed stream FS(0) is assumed to be 10000 Nm 3 / h, and with individual flow values ​​Nm according to the indication 3 / h flow rate to calculate the corresponding volume flow ratio.

[0990] Based on these inputs, two different scenarios were calculated:

[0991] 1. Reaction and membrane separation at 400 °C, 50 bar (absolute) feed pressure, 3 consecutive stages;

[0992] 2.500°C reaction temperature and 400°C membrane separation, 50 (absolute) bar, 2 consecutive stages.

[0993] The same membrane area and module distribution as for the inventive examples were assumed.For each inventive example, there were two reference examples: one at low permeate pressure (1.5 absolute bar) and one at high permeate pressure (10 absolute bar).

[0994] The gas mixture produced by the reactor is treated as an ideal gas, and the flow volume increases in proportion to the increase in the number of gas molecules. Therefore, F1 has a larger volume flow than FS(0), and the volume flow is proportional to the increase in the number of gas molecules.

[0995] The results of different simulations are summarized in the following reference examples, examples and associated tables. About the physical meaning of the simulation and the results produced therefrom, it is known to the technician that under real conditions, the impurities in the permeate are produced by the defects in the Pd film, and according to the solution diffusion mechanism, the film itself has theoretically infinite selectivity. It is also known that the amount of defects depends on the engineering and size of the membrane module. Therefore, although the results of the simulation suggest infinite selectivity, the technician recognizes that the selectivity of the Pd film is limited by the defects under real conditions. Therefore, the technician will also understand that the defects will be reduced in proportion to the Pd film area, because there is a smaller edge / membrane surface area, which is known to be the main source of the defects of the film.

[0996] Comparative Example 1: Two consecutive stages with a single membrane unit and collection of permeate at 10 bara

[0997] According to reference example 1, for Figure 1 The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 400 m3 / h is fed into the reactor CR(1) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F(1) at 673.15 K and 50 absolute bar through a reactor having 400 m3 / h. 2 A membrane stage M1 (1) with a membrane area of ​​1000 m2 is provided, a permeate stream P (1) containing pure H2 is obtained at 673.15 K and 10 absolute bar, and a retentate stream R (1) containing a mixture of NH3, N2 and H2 is obtained at 673.15 K and 50 absolute bar. The retentate stream R (1) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (2) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (2) at 673.15 K and 50 absolute bar through a reactor having 200 m2 of 2A membrane stage M1 (2) with a membrane area of ​​600 m2 was used to obtain a permeate stream P (2) containing pure H2 at 673.15 K and 10 absolute bar, and a retentate stream R (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2 The Pd membrane surface area converted a total of 94.4% of the ammonia and produced a 72.8% hydrogen recovery, both % conversion and % recovery were determined on a molar basis.

[0998] Table 1 Comparative results and flow ratio of Example 1

[0999]

[1000] Comparative Example 2: Two consecutive stages with a single membrane unit and collection of permeate at 1.5 bara

[1001] According to reference example 1, for Figure 1 The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 400 m3 / h is fed into the reactor CR(1) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F(1) at 673.15 K and 50 absolute bar through a reactor having 400 m3 / h. 2 A membrane stage M1 (1) with a membrane area of ​​1.500 m2 is provided, at 673.15 K and 1.500 m2 a permeate stream P (1) containing pure H2 is obtained, and at 673.15 K and 500 m2 a retentate stream R (1) containing a mixture of NH3, N2 and H2 is obtained. The retentate stream R (1) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (2) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (2) at 673.15 K and 500 m2 through a reactor having 200 m2 of 2 A membrane stage M1 (2) with a membrane area of ​​600 m2 was used to obtain a permeate stream P (2) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2 The Pd membrane surface area converted a total of 97.8% of the ammonia and produced a 96.7% hydrogen recovery, both conversion % and recovery % were determined based on volumetric measurements assuming ideal gas behavior.

[1002] Table 2 Comparative results and flow ratio of Example 2

[1003]

[1004] Example 1: Two consecutive stages with two membrane units connected in series

[1005] According to reference example 1, for Figure 2 The system of a single stage is simulated. The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 1.577 g / h is fed into the reactor CR(1) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F1(1) at 673.15 K and 50 absolute bar through a reactor having 200 m3 / s. 2 The first membrane stage M1(1) of the membrane area of ​​1000 m2 is provided with a permeate stream P1(1) containing pure H2 at 673.15 K and 10 absolute bar, and a retentate stream R1(1) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R1(1) containing a mixture of NH3, N2 and H2 is passed as feed gas stream F2(1) at 673.15 K and 50 absolute bar through a 200 m2 2 The second membrane stage M2 (1) has a membrane area of ​​1000 m2 and a permeate stream P2 (1) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R2 (1) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R2 (1) containing a mixture of NH3, N2 and H2 is fed to the reactor CR (2) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F1 (2) at 673.15 K and 50 absolute bar through a 100 m2 reactor. 2 A membrane stage M1 (2) with a membrane area of ​​100 m2 is provided at 673.15 K and 10 absolute bar to obtain a permeate stream P1 (2) containing pure H2 and a retentate stream R1 (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R1 (2) containing a mixture of NH3, N2 and H2 is passed as feed gas stream F2 (2) at 673.15 K and 50 absolute bar through a 100 m2 membrane stage M1 (2) with a membrane area of ​​100 m2 2 The second membrane stage M2 (2) with a membrane area of ​​600 m2 / s was used to obtain a permeate stream P2 (2) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R2 (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2The Pd membrane surface area converted a total of 96.6% of NH3 and produced a 91.5% H2 recovery. With respect to hydrogen pressure, a 40.1% H2 recovery was separated at 10 abs. bar, calculated as the total volume flow of permeate H2 at 10 abs. bar / sum of the volume flow of permeate H2 at 10 and 1.5 abs. bar, in which no correction for pressure and volume was made, and both conversion % and recovery % were based on volumetric determinations assuming ideal gas behavior.

[1006] Table 3 Results and flow ratios of Example 1

[1007]

[1008] The retentate stream R1(1) is identical in composition and parameters to the feed gas stream F2(1) (F2(1) is not shown in Table 3). The retentate stream R1(2) is also identical in composition and parameters to the feed gas stream F2(2) (F2(2) is also not shown in Table 3).

[1009] Comparative Example 3: Three consecutive stages with a single membrane unit and collection of permeate at 10 bar (absolute pressure)

[1010] According to reference example 1, for Figure 1 The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 400 m3 / h is fed into the reactor CR(1) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F(1) at 673.15 K and 50 absolute bar through a reactor having 400 m3 / h. 2 A membrane stage M1 (1) with a membrane area of ​​1000 m2 is provided, a permeate stream P (1) containing pure H2 is obtained at 673.15 K and 10 absolute bar, and a retentate stream R (1) containing a mixture of NH3, N2 and H2 is obtained at 673.15 K and 50 absolute bar. The retentate stream R (1) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (2) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (2) at 673.15 K and 50 absolute bar through a reactor having 200 m2 of 2The membrane stage M1 (2) has a membrane area of ​​10000 m / s and a permeate stream P (2) containing pure H2 at 673.15 K and 10 absolute bar, and a retentate stream R (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R (2) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (3) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (3) at 673.15 K and 50 absolute bar through a reactor having 200 m / s. 2 A membrane stage M1 (3) with a membrane area of ​​800 m2 was used to obtain a permeate stream P (3) containing pure H2 at 673.15 K and 10 absolute bar, and a retentate stream R (3) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2 The Pd membrane surface area converted a total of 88.3% of the ammonia and produced a 73.3% hydrogen recovery, both conversion % and recovery % were determined volumetrically assuming ideal gas behavior.

[1011] Table 4 Comparative results and flow ratio of Example 3

[1012]

[1013] Comparative Example 4: Three consecutive stages with a single membrane unit and collection of permeate at 1.5 bara

[1014] According to reference example 1, for Figure 1 The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 400 m3 / h is fed into the reactor CR(1) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F(1) at 673.15 K and 50 absolute bar through a reactor having 400 m3 / h. 2 A membrane stage M1 (1) with a membrane area of ​​1.500 m2 is provided, at 673.15 K and 1.500 m2 a permeate stream P (1) containing pure H2 is obtained, and at 673.15 K and 500 m2 a retentate stream R (1) containing a mixture of NH3, N2 and H2 is obtained. The retentate stream R (1) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (2) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (2) at 673.15 K and 500 m2 through a reactor having 200 m2 of 2The membrane stage M1 (2) has a membrane area of ​​1000 m / s and a permeate stream P (2) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R (2) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (3) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F (3) at 673.15 K and 50 absolute bar through a reactor having 200 m / s. 2 A membrane stage M1 (3) with a membrane area of ​​800 m2 was used to obtain a permeate stream P (3) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R (3) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2 The Pd membrane surface area converted a total of 96.8% of the ammonia and produced a 95.7% hydrogen recovery, both conversion % and recovery % were determined volumetrically assuming ideal gas behavior.

[1015] Table 5 Results and flow ratios of reference example 5

[1016]

[1017]

[1018] Example 2: Three consecutive stages with two membrane units connected in series

[1019] According to reference example 1, for Figure 2 The system of a single stage is simulated. The flow rate is 10000Nm 3 A NH3 feed stream FS(0) of 1.577 N / h is fed into the reactor CR(1) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F1(1) at 673.15 K and 50 absolute bar through a reactor having 200 m3 of NH3. 2 The first membrane stage M1(1) of the membrane area of ​​1000 m2 is provided with a permeate stream P1(1) containing pure H2 at 673.15 K and 10 absolute bar, and a retentate stream R1(1) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R1(1) containing a mixture of NH3, N2 and H2 is passed as feed gas stream F2(1) at 673.15 K and 50 absolute bar through a 200 m2 2The second membrane stage M2 (1) has a membrane area of ​​100 m2 / s and a permeate stream P2 (1) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R2 (1) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R2 (1) containing a mixture of NH3, N2 and H2 is fed to the reactor CR (2) and converted at 673.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F1 (2) at 673.15 K and 50 absolute bar through a 100 m2 / s reactor. 2 A membrane stage M1 (2) with a membrane area of ​​100 m2 is provided at 673.15 K and 10 absolute bar to obtain a permeate stream P1 (2) containing pure H2 and a retentate stream R1 (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R1 (2) containing a mixture of NH3, N2 and H2 is passed as feed gas stream F2 (2) at 673.15 K and 50 absolute bar through a 100 m2 membrane stage M1 (2) with a membrane area of ​​100 m2 2 The second membrane stage M2 (2) with a membrane area of ​​100 m2 / s is provided to obtain a permeate stream P2 (2) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R2 (2) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R2 (2) containing a mixture of NH3, N2 and H2 is fed to a reactor CR (3) and converted at 773.15 K to obtain a gas mixture consisting of NH3, N2 and H2, which is passed as gas stream F1 (3) at 673.15 K and 50 absolute bar through a reactor having 100 m2 / s. 2 A membrane stage M1 (3) with a membrane area of ​​100 m2 is provided at 673.15 K and 10 absolute bar to obtain a permeate stream P1 (3) containing pure H2 and a retentate stream R1 (3) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. The retentate stream R1 (3) containing a mixture of NH3, N2 and H2 is passed as feed gas stream F2 (3) at 673.15 K and 50 absolute bar through a 100 m2 membrane stage M1 (3) having a membrane area of ​​100 m2 2 The second membrane stage M2 (3) with a membrane area of ​​800 m2 / s was used to obtain a permeate stream P2 (3) containing pure H2 at 673.15 K and 1.5 absolute bar, and a retentate stream R2 (3) containing a mixture of NH3, N2 and H2 at 673.15 K and 50 absolute bar. 2The Pd membrane surface area converted a total of 95.5% of the NH3 and produced a 91.9% H2 recovery. With respect to the pressure of hydrogen, a 38% H2 recovery was separated at 10 abs. bar, calculated as the total volume flow of permeate H2 at 10 abs. bar / sum of the volume flow of permeate H2 at 10 and 1.5 abs. bar, in which there was no correction for pressure and volume, and both conversion % and recovery % were based on volumetric determinations assuming ideal gas behavior.

[1020] Table 6 Results and flow ratio of Example 2

[1021]

[1022] The retentate stream R1(1) is identical in composition and parameters to the feed gas stream F2(1) (F2(1) is not shown in Table 3). The retentate stream R1(2) is also identical in composition and parameters to the feed gas stream F2(2) (F2(2) is also not shown in Table 3). Finally, the retentate stream R1(3) is also identical in composition and parameters to the feed gas stream F2(3) (F2(3) is also not shown in Table 3). BRIEF DESCRIPTION OF THE DRAWINGS

[1023] Figure 1 A flow chart for a single stage according to the prior art is depicted, wherein a feed source FS(i-1) of NH3 enters a conversion reactor CR(i), which converts the NH3 into a mixture of NH3, N2 and H2, which is then sent as feed gas F(i) to a membrane unit M(i) comprising a Pd membrane, which then separates the mixture into a permeate gas stream P(i) containing purified H2 and a retentate R(i) containing a mixture of NH3, N2 and H2.

[1024] Figure 2 A flow chart for a single stage according to the invention is depicted, wherein a feed source FS(i-1) of NH3 enters a conversion reactor CR(i), which converts the NH3 into a mixture of NH3, N2 and H2, which is then sent as feed gas F(i) to a membrane unit M(i) comprising a Pd membrane, which then separates the mixture into a permeate gas stream P(i) containing purified H2 and a retentate R(i) containing a mixture of NH3, N2 and H2.

[1025] Figure 3 Depicted with Figure 1 The same flow diagram according to the prior art for a single stage, except that the heat exchange device H(i) for adjusting the temperature of F(i) before entering the membrane unit M1(i) is shown.

[1026] Figure 4 Depicted with Figure 2 The same flow diagram for a single stage according to the invention, except that the heat exchange device H(i) for adjusting the temperature of F1(i) before entering the membrane unit M1(i) is shown.

[1027] References

[1028] -Cechetto et.al.proposes in “H2production via ammonia decomposition in a catalytic membrane reactor”, Fuel Processing Technology (2021), page 106772

[1029] -Yun et al reviews in “correlations of in palladium membranes for hydrogen separation” J.Membrane Sci. (2011) pages 28to 45

[1030] -Schüth et al reviews in “Ammonia as a possible element in an energyinfrastructure:catalysts for ammonia decomposition” Energy Eviron.Sci.2012, page 6278,

[1031] -Abashar discloses in “Ultra-clean hydrogen production by ammoniaDecomposition”, J. King Saud University-Engineering Sciences (2018) pages 2-11

[1032] -Lamb et al.in "Ammonia for hydrogen storage; A review of catalyticammonia decomposition and hydrogen separation and purification", Int.J.ofhydrogen energy, 44 (2019) 3580

[1033] -Murugan et al in“Review of purity analysis methods for performingquality assurance of fuel cell hydrogen”Int.Journal of Hydrogen Energy(2015)pg 4219

[1034] -Pal N.et al,A review on types,fabrication and support material ofhydrogen separation membrane,Materials Today:Proceedings,volume 28,part 3,2020,pages 1386-1391 with regards to acceptable substrate materials forpalladium comprising membranes

Claims

1. A method for recovering H2 from the conversion of NH3 in a device comprising n zones Z(i) connected in series, where i=1 ... n, where n≥2, Each zone Z(i) includes a conversion reactor CR(i) comprising a catalyst C(i) for converting NH3 to give H2, - the first membrane unit M1(i) and - a second membrane unit M2(i), wherein in Z(i), CR(i) is located upstream of M1(i) and M2(i) is located downstream of M1(i), wherein Z(1) is the most upstream zone and Z(n) is the most downstream zone, The method includes (a) providing a feed gas stream FS(0) comprising NH3; (b) n consecutive processing stages S(i), i=1…n, in, In each S(i), S(i) includes The conversion phase SA(i) includes - feeding a feed gas stream FS(i-1) into a conversion reactor CR(i) included in Z(i) and contacting said stream FS(i-1) with C(i) in CR(i) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(i) having a molar ratio n(H2):n(NH3)=x(G(i)); - removing the gas stream G(i) comprising NH3, N2 and H2 from CR(i); - passing this gas stream G(i) as feed gas stream F1(i) through a separation stage SB(i), F1(i) having the same chemical composition as G(i) and the molar ratio x(G(i))=x(F1(i)); The separation stage SB(i) comprises - passing the feed gas stream F1(i) through a first membrane unit M1(i) comprising at least one membrane of Z(i) at a pressure ratio φ, The at least one membrane has a H2 / NH3 selectivity of at least 2000, the pressure ratio across said at least one membrane, calculated as (pressure of feed gas stream F1(i) / pressure of permeate gas stream P1(i)) at constant temperature, is greater than 1, obtaining a permeate gas stream P1(i) comprising H2; and o A retentate gas stream R1(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(i)); x(R1(i)) <x(F1(i)); - passing the retentate gas stream R1(i) through a separation stage SC(i) as feed gas stream F2(i), F2(i) having the same chemical and physical composition and molar ratio x(R1(i))=x(F2(i)) as R1(i); The separation stage SC(i) comprises - passing the feed gas stream F2(i) through a second membrane unit M2(i) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ, the pressure ratio across said at least one membrane, calculated as (pressure of feed gas stream F2(i) / pressure of permeate gas stream P2(i)) at constant temperature, is greater than 1, obtaining a permeate gas stream P2(i) comprising H2; and o A retentate gas stream R2(i) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(i)); x(R2(i)) <x(F2(i)); - removing the gas stream R2(i) from Z(i); wherein, when i=1 ... n-1, the gas stream R2(i) is removed from Z(i) as a feed stream FS(i), FS(i) having the same chemical and physical composition and molar ratio x(R2(i))=x(FS(i)) as R2(i); and wherein, when i=n, ​​the gas stream R2(n) is removed from Z(i) as a product gas stream; wherein the volume flow ratio of FS(i-1) to FS(i) is in the range of 1.05:1 to 4:

1.

2. The method of claim 1, wherein: n=2 to 10, preferably n=2 to 5, more preferably n=2, 3 or 4, more preferably n=2 or 3.

3. The method according to claim 1 or 2, wherein: According to stage S(i), no vacuum device or compressor is operated downstream of the conversion reactor CR(i) according to SA(i) when obtaining the permeate gas stream and / or the retentate gas stream, preferably when obtaining any permeate gas stream and / or any retentate gas stream.

4. The method according to any one of claims 1 to 3, wherein: According to SA(i), the feed gas stream FS(i-1) is contacted with the conversion catalyst C(i) at a pressure in the range of 10 to 100 bar (absolute pressure), more preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure), more preferably in the range of 15 to 85 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure); and Wherein, according to SA(i), the feed gas stream FS(i-1) is preferably contacted with the conversion catalyst C(i) at a temperature in the range of 50°C to 1100°C, more preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C, more preferably in the range of 100°C to 1000°C, more preferably in the range of 350°C to 900°C.

5. The method according to any one of claims 1 to 4, wherein: The conversion catalyst C(i) comprises, more preferably consists of, a transition metal supported on a refractory support material; The transition metal is selected from the group consisting of: Composition: Fe, Cu, Ni, Co, Ru, Ag, Pd, Rh, Pt, Ir, including combinations of two or more thereof, more preferably selected from the group consisting of Ni, Co, Rh and Ru, including combinations of two or more thereof, more preferably Ni, Co or Ru, more preferably Ru; The refractory carrier material is preferably selected from the group consisting of: zeolite, alumina, silica, titania, zirconia, ceria, lanthanum oxide, praseodymium oxide, neodymium oxide, yttrium oxide, activated carbon, carbon nanotubes and a combination of two or more thereof, more preferably selected from the group consisting of: alumina, silica, titania, zirconia and a combination of two or more thereof, more preferably alumina or zirconia.

6. The method according to any one of claims 1 to 5, wherein: The gas stream G(i) has a molar ratio x(G(i)) of H2 to NH3 in the range of 0.01:1 to 500:1, more preferably in the range of 0.05:1 to 200:1, more preferably in the range of 2:1 to 50:1 (calculated as n(H2):n(NH3)=x(G(i))); wherein the gas stream G(i) has a molar ratio y(G(i)) of H2 to N2 in the range of 0.01:1 to 5:1 (calculated as n(H2):n(N2)=y(G(i))); wherein the gas stream G(i) preferably has a pressure in the range of 10 to 100 bar (absolute pressure), more preferably in the range of 15 to 65 bar (absolute pressure), more preferably in the range of 20 to 60 bar (absolute pressure); Therein, the gas stream G(i) more preferably has a temperature in the range of 50°C to 1100°C, more preferably in the range of 350°C to 900°C.

7. The method according to any one of claims 1 to 6, wherein: passing the feed gas stream F1(i) through a heat exchanger H(i) before passing through the separation stage SB(i); wherein the feed gas stream F1(i) more preferably has a temperature in the range of 250°C to 700°C, more preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C after passing through H(i); Therein the feed gas stream F1(i) more preferably has a pressure in the range of 10 to 100 bar (absolute), more preferably in the range of 15 to 85 bar (absolute), more preferably in the range of 20 to 60 bar (absolute).

8. The method according to any one of claims 1 to 7, wherein: According to SB(i), the at least one membrane included in the membrane unit M1(i) is a palladium metal membrane; wherein, according to SB(i), the membrane unit M1(i) comprising at least one membrane preferably has a H2 / NH3 selectivity of at least 2500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000; Therein, according to SB(i), the membrane unit M1(i) comprising at least one membrane preferably has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:

1.

9. The method according to any one of claims 1 to 8, wherein: According to SB(i), the pressure ratio φ calculated as (pressure of feed gas stream F1(i) / pressure of permeate gas stream P1(i)) at constant temperature across the at least one membrane comprised in membrane unit M1(i) is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, more preferably in the range of 2.5:1 to 35:1; wherein, according to SB(i), the permeate gas stream P1(i) preferably has a pressure in the range of 3 to 30 bara, more preferably in the range of 5 to 20 bara, more preferably in the range of 5 to 15 bara; Therein, according to SB(i), the permeate gas stream P1(i) more preferably has a temperature in the range of 250 to 700°C, more preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

10. The method according to any one of claims 1 to 9, wherein: According to SC(i), the at least one membrane included in the membrane unit M2(i) is a palladium metal membrane; wherein the membrane unit M2(i) comprising at least one membrane has a H2 / NH3 selectivity of at least 2500, more preferably in the range of 2,500 to 1,000,000, more preferably in the range of 4,500 to 900,000, more preferably in the range of 5,000 to 800,000, more preferably in the range of 6,000 to 600,000, according to SC(i); Therein, according to SC(i), the membrane unit M2(i) comprising at least one membrane has a ratio of H2 / N2 selectivity to H2 / NH3 selectivity in the range of 0.8:1 to 5:1, more preferably in the range of 1.2:1 to 2:

1.

11. The method according to any one of claims 1 to 10, wherein: According to SC(i), the pressure ratio φ calculated as (pressure of feed gas stream F2(i) / pressure of permeate gas stream P2(i)) at constant temperature across the at least one membrane comprised in membrane unit M2(i) is in the range of 1.5:1 to 50:1, more preferably in the range of 2:1 to 40:1, more preferably in the range of 2.5:1 to 35:1; wherein, according to SC(i), the permeate gas stream P2(i) preferably has a pressure in the range of 1.1 to 30 bar (absolute pressure), preferably in the range of 1.1 to 10 bar (absolute pressure), more preferably in the range of 1.1 to 2.5 bar (absolute pressure); Therein, according to SC(i), the permeate gas stream P2(i) more preferably has a temperature in the range of 250 to 700°C, preferably in the range of 300 to 600°C, more preferably in the range of 350 to 500°C.

12. The method according to any one of claims 1 to 11, wherein: According to SC(i), the retentate gas stream R2(i) has a molar ratio x(R2(i)) of H2 to NH3 in the range of 0.05:1 to 100:1, preferably in the range of 0.1:1 to 30:1, more preferably in the range of 0.2:1 to 5:1 (calculated as n(H2):n(NH3)=x(R2(i))=x(FS(i))); wherein, according to SC(i), the retentate gas stream R2(i) preferably has a molar ratio y(R2(i)) of H2 to N2 in the range of 0.01:1 to 2:1, preferably in the range of 0.03:1 to 2:1, more preferably in the range of 0.05:1 to 1.5:1 (calculated as n(H2):n(N2)=y(R2(i))=y(FS(i))); Among them, according to SC(i), the volume flow ratio of F2(i) and R2(i) calculated as (volume flow F2(i) / volume flow R2(i)) is more preferably in the range of 1:1 to 5:1, preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:

1.

13. The method according to any one of claims 1 to 12, wherein: According to SC(n), the retentate gas stream R2(n) has a pressure in the range of 10 to 100 bara; wherein, according to SC(n), the retentate gas stream R2(n) preferably has a temperature in the range of 250°C to 700°C, more preferably in the range of 300°C to 600°C, more preferably in the range of 350°C to 500°C; wherein the retentate gas stream R2(n) more preferably has a molar ratio x(R2(i)) of H2 to NH3 (calculated as n(H2):n(NH3)=x(R2(n))) in the range of 0.05:1 to 100:1, more preferably in the range of 0.1:1 to 30:1, more preferably in the range of 0.2:1 to 5:1, according to SC(n); wherein the retentate gas stream R2(n) more preferably has a molar ratio y(R2(i)) of H2 to N2 (calculated as n(H2):n(N2)=y(R2(n))) in the range of 0.01:1 to 2:1, more preferably in the range of 0.03:1 to 2:1, more preferably in the range of 0.05:1 to 1.5:1, according to SC(n); Among them, according to SC(n), the volume flow ratio of F2(n) to R2(n) calculated as (volume flow F2(n) / volume flow R2(n)) is more preferably in the range of 1:1 to 5:1, more preferably in the range of 1:1 to 3.5:1, and more preferably in the range of 1.02:1 to 2:

1.

14. The method according to any one of claims 1 to 13, wherein: The volume flow ratio of FS(i-1) to (FS(i)) is in the range of 1.1:1 to 3:1, preferably in the range of 1.2:1 to 2.5:1; wherein the ratio of the pressure of the permeate gas stream P1(i) to the permeate gas stream P2(i) is in the range of 50:1 to 1.5:1, preferably in the range of 20:1 to 2:1, more preferably in the range of 15:1 to 3:1, more preferably in the range of 12:1 to 4:

1.

15. A method for recovering H2 from the conversion of NH3 in a plant comprising a zone Z(1) comprising a conversion reactor CR(1) comprising a catalyst C(1) for converting NH3 to give H2, a first membrane unit M1(1) and a second membrane unit M2(1), where in Z(1), CR(1) is located upstream of M1(1) and M2(1) is located downstream of M1(1), The method includes (a) providing a feed gas stream FS(0) comprising NH3; (b) Processing stage S(1), where S(1) includes The conversion phase SA (1) includes - feeding a gas stream FS(0) into a conversion reactor CR(1) comprised in Z(i) and contacting said stream FS(0) with C(1) in CR(1) to obtain a gas stream G(i) comprising NH3, N2 and H2, said gas stream G(1) having a molar ratio n(H2):n(NH3)=x(G(1)); - removing the gas stream G(1) comprising NH3, N2 and H2 from CR(1); - passing this gas stream G(1) through a separation stage SB(1) as feed gas stream F1(1), F1(1) having the same chemical composition as G(1) and the molar ratio x(G(1))=x(F1(1)); The separation stage SB (1) comprises - passing the feed gas stream F1(1) through a first membrane unit M1(1) comprising at least one membrane of Z(1) at a pressure ratio φ, The at least one membrane has a H2 / NH3 selectivity of at least 2000, the pressure ratio across said at least one membrane, calculated as (pressure of feed gas stream F1(i) / pressure of permeate gas stream P1(1)) at constant temperature, is greater than 1, obtaining a permeate gas stream P1(1) comprising H2; and o A retentate gas stream R1(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R1(1)); x(R1(1)) <x(F1(1)); - passing the retentate gas stream R1(1) through a separation stage SC(1) as feed gas stream F2(1), F2(1) having the same chemical and physical composition as R1(1) and the molar ratio x(R1(1))=x(F2(1)); The separation stage SC (1) comprises - passing the feed gas stream F2(1) through a second membrane unit M2(1) of Z(i) comprising at least one membrane having a H2 / NH3 selectivity of at least 2000 at a pressure ratio φ, the pressure ratio across said at least one membrane, calculated as (pressure of feed gas stream F2(1) / pressure of permeate gas stream P2(1)) at constant temperature, is greater than 1, obtaining a permeate gas stream P2(1) comprising H2; and o A retentate gas stream R2(1) comprising H2, N2 and NH3, wherein the molar ratio n(H2):n(NH3)=x(R2(1)); x(R2(1)) <x(F2(1)); - removing the gas stream R2(1) from Z(1); wherein the gas stream R2(1) is removed from Z(1) as a product gas stream; The volume flow ratio of FS(0) to R2(1) is in the range of 1.05:1 to 4:

1.

16. A device for recovering H2 from converting NH3, preferably according to the method of any one of claims 1 to 15, comprising n zones Z(i), where i=1…n, where n≥1, in, When n≥2, the n zones Z(i) are connected in series and Z(1) is the most upstream zone and Z(n) is the most downstream zone, Each zone Z(i) includes The conversion reactor unit U.CR(i) comprises - a supply device for supplying a feed stream FS(i-1) comprising NH 3 to the conversion reactor CR(i); a conversion reactor CR(i) for converting NH3 into a gas stream G(i) comprising NH3, N2 and H2, the conversion reactor CR(i) comprising a conversion catalyst C(i); - outlet means for removing the gas stream G(i) as feed gas stream F1(i) from CR(i) to the membrane separation unit U.M1(i); The first membrane separation unit U.M1(i) comprises - means for sending the feed gas stream F1(i) to the first membrane unit M1(i); - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000; - outlet means for removing the permeate gas stream P1 (i) from the membrane unit M1 (i); - outlet means for removing a retentate gas stream R1 (i) from the membrane unit M1 (i); The second membrane separation unit U.M2(i) comprises - means for feeding the retentate gas stream R1(i) as feed gas stream F2(i) to the second membrane unit M2(i); - the membrane unit comprises at least one membrane having a H2 / NH3 selectivity of at least 2000; - outlet means for removing the permeate gas stream P2(i) from the membrane unit M2(i); outlet means for removing a retentate gas stream R2(i) from Z(i); as well as means for sending R2(i) removed from Z(i) as feed stream FS(i) to Z(i+1) when n≥2 and i≠n; In Z(i), U.CR(i) is located upstream of U.M1(i) and U.M2(i) is located downstream of U.M1(i).

17. The apparatus of claim 16, wherein: n=1 to 10, preferably n=1 to 5, more preferably n=1, 2, 3 or 4, more preferably n=1 or 2 or 3; Therein no vacuum device or compressor is arranged downstream of the conversion reactor CR(i) according to U.CR(i).

18. Use of the apparatus as claimed in any one of claims 16 or 17 in a process for recovering H2 from converting NH3.

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