Ammonia decomposition hydrogen production system and method thereof, catalytic oxidation catalyst and gas treatment method

Abstract

The invention discloses an ammonia decomposition hydrogen production system and method, a catalytic oxidation catalyst and a gas treatment method. The system comprises an ammonia conversion device, a deamination device and a hydrogen purification device, wherein the ammonia conversion device is of a shell-and-tube structure, a tube pass is an ammonia decomposition reaction area and is provided with an ammonia raw material inlet and a decomposed gas outlet, and a shell pass is a catalytic oxidation reaction area and is provided with an oxidation reaction inlet and a flue gas outlet; the decomposed gas outlet is communicated with the deamination device and is used for removing residual ammonia; the deamination device is communicated with the hydrogen purification device and is used for purifying hydrogen; the oxidation reaction inlet is communicated with the hydrogen purification device, and the oxidation reaction inlet is also communicated with the flue gas outlet. The ammonia conversion device adopted by the system is of a shell-and-tube structure, and heat generated by catalytic oxidation reaction provides heat energy for ammonia decomposition reaction, so that an external heat source and equipment do not need to be additionally added in the whole hydrogen production process, and the energy efficiency is higher.

Description

Technical Field

[0001] The invention relates to the field of hydrogen production by decomposing ammonia, and in particular to a system and a method for hydrogen production by decomposing ammonia, as well as a catalytic oxidation catalyst and a gas treatment method. Background Art

[0002] Low cost, high density and safe storage and transportation of hydrogen are the key challenges faced in realizing large-scale application of hydrogen energy. Among the many hydrogen storage solutions, ammonia (NH3) is considered to be the most promising and efficient liquid storage and transportation carrier. In the process of hydrogen production by ammonia decomposition, ammonia generates hydrogen and nitrogen under certain temperature and pressure conditions under the action of an ammonia decomposition catalyst, and then undergoes temperature swing adsorption (TSA) deamination and pressure swing adsorption (PSA) purification to separate H2 and N2 to obtain high-purity hydrogen.

[0003] In the actual production process, the desorbed gas after pressure swing adsorption contains a large amount of H2 and residual ammonia, the combustible gas content is greater than 30% by volume, and the residual ammonia emission has pollution problems. At the same time, in the prior art, TSA is regenerated by nitrogen, and the regeneration tail gas treatment requires additional environmental protection facilities and the ammonia utilization rate is not high. The ammonia decomposition hydrogen production reaction is an endothermic reaction, and the entire device requires an external heat source. In the prior art, some ammonia decomposition hydrogen production devices use electric heating systems as heat sources, which have the problem of high comprehensive energy consumption.

[0004] Traditional ammonia cracking hydrogen production technology has problems such as high energy consumption, low production efficiency, and many ancillary projects. It is limited to small-scale applications such as glass factories and steel mills, and is difficult to match with hydrogen terminals in hydrogen refueling stations. Therefore, there is an urgent need to develop an efficient, environmentally friendly green ammonia hydrogen production method suitable for hydrogen refueling station scenarios to achieve large-scale terminal applications of green hydrogen. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of low comprehensive energy efficiency and waste gas emissions of ammonia decomposition in the prior art, and to provide an ammonia decomposition hydrogen production system and method, as well as a catalytic oxidation catalyst and a gas treatment method to achieve effective utilization of desorbed gas and recycling of residual ammonia.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an ammonia decomposition hydrogen production system, which includes an ammonia conversion device, a deamination device and a hydrogen purification device; wherein the ammonia conversion device is a shell and tube structure, the tube side is an ammonia decomposition reaction zone, provided with an ammonia raw material inlet and a decomposition gas outlet, and the shell side is a catalytic oxidation reaction zone, provided with an oxidation reaction inlet and a flue gas outlet; the decomposition gas outlet is connected to the deamination device for removing residual ammonia; the deamination device is connected to the hydrogen purification device for purifying hydrogen; the oxidation reaction inlet is connected to the hydrogen purification device for passing the desorbed gas of the hydrogen purification device into the catalytic oxidation reaction zone, and the oxidation reaction inlet is also connected to the flue gas outlet for passing the circulating flue gas from the flue gas outlet into the catalytic oxidation reaction zone through the oxidation reaction inlet.

[0007] A second aspect of the present invention provides an ammonia decomposition reaction method for producing hydrogen by ammonia decomposition, the method comprising: in the presence of an ammonia decomposition catalyst, subjecting an ammonia-containing raw material to an ammonia decomposition reaction in an ammonia decomposition reaction zone to obtain a decomposed gas; and sequentially deammonifying and hydrogen purifying the decomposed gas to obtain hydrogen;

[0008] In the presence of a catalytic oxidation catalyst, air, circulating flue gas and the desorbed gas after the hydrogen is purified are subjected to a catalytic oxidation reaction in a catalytic oxidation reaction zone to provide heat for the ammonia decomposition reaction; the flue gas generated by the catalytic oxidation reaction is discharged from the outlet of the catalytic oxidation reaction zone, and at least a part of the flue gas enters the catalytic oxidation reaction zone as a circulating flue gas to undergo a catalytic oxidation reaction;

[0009] The ammonia decomposition reaction zone is located in the tube side of the shell and tube ammonia decomposition device, and the catalytic oxidation reaction zone is located in the shell side of the shell and tube ammonia decomposition device.

[0010] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0011] The ammonia conversion device used in the system of the present invention is a shell and tube structure. A catalytic oxidation reaction occurs in the catalytic oxidation reaction zone, and the heat generated provides thermal energy for the ammonia decomposition reaction zone. The temperatures and heat absorption and release conditions of the two reaction zones match each other, so that the entire hydrogen production process does not require additional external heat sources and equipment, and has higher energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic flow chart of a method for producing hydrogen by decomposing ammonia provided in one embodiment of the present invention;

[0013] Figure 2 is a schematic structural diagram of an ammonia conversion device provided in one embodiment of the present invention;

[0014] Figure 3 yes Figure 2A longitudinal sectional view of the ammonia conversion unit shown;

[0015] Figure 4 yes Figure 2 A cross-sectional view of an ammonia conversion unit is shown.

[0016] Description of Reference Numerals

[0017] A Ammonia conversion unit A1 Ammonia raw material inlet A2 Decomposition gas outlet

[0018] A3 Oxidation reaction inlet A4 Flue gas outlet B Deammoniation device

[0019] C Hydrogen purification device D Heat exchanger E Hydrogen buffer

[0020] F Desorption gas buffer G Smoke gas buffer

[0021] 1 Ammonia feed pipeline 2 Hydrogen product pipeline 3 Regeneration deammoniation pipeline

[0022] 4Decomposition gas pipeline 5Crude deamination pipeline 6High purity hydrogen pipeline

[0023] 7 Purge gas pipeline 8 Desorption gas pipeline 9 Air pipeline

[0024] 10 circulating flue gas outlet pipeline 11 circulating flue gas inlet pipeline 12 flue gas discharge pipeline DETAILED DESCRIPTION

[0025] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] The first aspect of the present invention provides a system for producing hydrogen by decomposing ammonia, such as Figures 1 to 4As shown, the system includes an ammonia conversion device A, a deamination device B and a hydrogen purification device C; wherein the ammonia conversion device A is a shell and tube structure, the tube side is an ammonia decomposition reaction zone, provided with an ammonia raw material inlet A1 and a decomposition gas outlet A2, and the shell side is a catalytic oxidation reaction zone, provided with an oxidation reaction inlet A3 and a flue gas outlet A4; the decomposition gas outlet A2 is connected to the deamination device B for removing residual ammonia; the deamination device B is connected to the hydrogen purification device C for purifying hydrogen; the oxidation reaction inlet A3 is connected to the hydrogen purification device C for passing the desorbed gas of the hydrogen purification device C into the catalytic oxidation reaction zone, the oxidation reaction inlet A3 is connected to the flue gas outlet A4 for passing the circulating flue gas of the flue gas outlet A4 into the catalytic oxidation reaction zone through the oxidation reaction inlet A3, and the oxidation reaction inlet A3 is also connected to the air pipeline 9 for passing fresh air into the catalytic oxidation reaction zone.

[0027] In the present invention, the tube side is an ammonia decomposition reaction zone for carrying out an ammonia decomposition reaction, that is, an ammonia decomposition hydrogen production reaction; the shell side is a catalytic oxidation reaction zone for carrying out a catalytic oxidation reaction to provide heat for the ammonia decomposition reaction in the tube side.

[0028] In the present invention, the deammoniation device includes a residual ammonia removal outlet and a hydrogen outlet. The residual ammonia removal outlet is connected to the ammonia conversion device A and is used to mix the residual ammonia with the raw gas after heat exchange and enter the ammonia decomposition reaction zone of the ammonia conversion device A; the hydrogen outlet is connected to the hydrogen purification device C for purifying hydrogen.

[0029] The ammonia decomposition hydrogen production system of the present invention has the characteristics of high efficiency and stability, can be matched with the hydrogen end of the hydrogen refueling station, and can be customized according to the needs of the hydrogen end. It can quickly and accurately respond to the terminal hydrogen demand, and can realize the recycling of residual ammonia in the ammonia cracking gas and the efficient recovery of desorption gas energy, and has the advantages of low carbon, environmental protection and low cost.

[0030] In some preferred embodiments of the present invention, the ammonia conversion device A comprises an ammonia decomposition reaction tube inserted into the bed of the catalytic oxidation reaction zone, and a plurality of uniformly arranged equal-diameter tubes are arranged in the ammonia conversion device A, and the tubes are filled with an ammonia decomposition catalyst to form a hydrogen production ammonia decomposition reaction zone. The distribution of the tube side and the shell side is as follows: Figures 2 to 4 As shown, material distributors are provided at the ammonia raw material inlet A1, the decomposition gas outlet A2, the oxidation reaction inlet A3 and the flue gas outlet A4.

[0031] In the present invention, the deamination device B is a temperature swing adsorption (TSA) deamination device; and the hydrogen purification device C is a pressure swing adsorption (PSA) device.

[0032] In some embodiments of the present invention, the ammonia decomposition reaction zone is filled with an ammonia decomposition catalyst.

[0033] In some embodiments of the present invention, the ammonia decomposition catalyst comprises a first metal active component and a first carrier, the first metal active component comprises a noble metal component I and a non-noble metal component II; the noble metal component I is Ru and / or Pd, and the non-noble metal component II is selected from one or more of Fe, Co, Ni and Cu;

[0034] In some embodiments of the present invention, based on the total weight of the ammonia decomposition catalyst, the content of the precious metal component I is 0.5-5wt%, preferably 0.8-4wt%; the content of the non-precious metal component II is 0.3-20wt%, preferably 1.5-10wt%; the content of the first carrier is 75-99.2wt%;

[0035] In some embodiments of the present invention, the particle size of the ammonia decomposition catalyst is 3 to 8 mm.

[0036] In some preferred embodiments of the present invention, the shape of the ammonia decomposition catalyst is one or more of spherical, clover-leaf, Raschig ring, and nest, more preferably nest, and even more preferably honeycomb.

[0037] In some embodiments of the present invention, in the ammonia decomposition catalyst, the precious metal component I is Pd and Ru, the non-precious metal component II is Fe, and the first carrier is γ-Al2O3.

[0038] In some embodiments of the present invention, the molar ratio of Pd:Ru:Fe is 1:1-2:3-6.

[0039] In the present invention, the preferred ammonia decomposition catalyst is used, which can effectively reduce the temperature of the ammonia decomposition reaction to below 480° C., and the ammonia conversion rate is greater than 95%.

[0040] In some embodiments of the present invention, the catalytic oxidation reaction zone is filled with a catalytic oxidation catalyst.

[0041] In some embodiments of the present invention, the catalytic oxidation catalyst includes a second metal active component and a second carrier, the second metal active component includes a precious metal component III and a non-precious metal component IV; the precious metal component III is Pt and / or Pd, and the non-precious metal component IV is selected from one or more of Mn, Mg, Fe, Co, Ni, Cu, Ag, Ce, W, Cu, Ca and La.

[0042] In some embodiments of the present invention, based on the total weight of the catalytic oxidation catalyst, the content of the precious metal component III is 0.01-1wt%, the content of the non-precious metal component IV is 0.03-20wt%, and the content of the second carrier is 79-99.96wt%.

[0043] In some embodiments of the present invention, the particle size of the catalytic oxidation catalyst is 3 to 5 mm.

[0044] In some preferred embodiments of the present invention, the shape of the catalytic oxidation catalyst is one or more of a spherical shape, a clover shape, a Raschig ring shape, and a nest shape, more preferably a nest shape, and even more preferably a honeycomb shape.

[0045] In some embodiments of the present invention, the catalytic oxidation reaction zone includes a direct oxidation zone and a deep oxidation zone, wherein the direct oxidation zone is located upstream of the catalytic oxidation reaction zone; and the deep oxidation zone is located downstream of the catalytic oxidation reaction zone.

[0046] In some embodiments of the present invention, the ratio of the layer height of the direct oxidation zone to the layer height of the deep oxidation zone is 1 to 2:1.

[0047] In some embodiments of the present invention, the direct oxidation zone is filled with a mixture of a direct oxidation catalyst and a thermally conductive inert material; and the deep oxidation zone is filled with a mixture of a deep oxidation catalyst and a thermally conductive inert material.

[0048] In some embodiments of the present invention, based on the total weight of the direct oxidation catalyst, the content of the precious metal component III is 0.01-0.04wt%, and the content of the non-precious metal component IV is 0.05-10wt%; preferably, in the direct oxidation catalyst, the precious metal component III is Pt, the non-precious metal component IV is Mn, and the second carrier is TiO2 and / or Al2O3; more preferably, the molar ratio of Pt:Mn is 1:1-1:8.

[0049] In the present invention, the direct oxidation catalyst can effectively reduce the starting temperature of catalytic oxidation and control the bed temperature, that is, the starting temperature at the inlet of the oxidation reactor is less than or equal to 10°C, and the bed temperature difference is less than 20°C.

[0050] In some embodiments of the present invention, based on the total weight of the deep oxidation catalyst, the content of the precious metal component III is 0.05-0.8wt%, and the content of the non-precious metal component IV is 0.05-15wt%; preferably, in the deep oxidation catalyst, the precious metal component III is Pt and Pd, the non-precious metal component IV is Mn and W, and the second carrier is one or more of CeO2, TiO2 and Al2O3; more preferably, the molar ratio of Pt:Pd:Mn:W is 1-2:1:1-8:1-6.

[0051] In the present invention, the deep oxidation catalyst can effectively reduce the outlet combustible concentration, oxidize hydrogen and residual ammonia into nitrogen and water, so that the combustible concentration at the outlet of the oxidation reaction zone is less than or equal to 1 mg / m 3 .

[0052] In some embodiments of the present invention, the thermally conductive inert material is selected from one or more of SiC, SiO2, AlN, BN and Al2O3, preferably SiC.

[0053] In some embodiments of the present invention, the particle size of the thermally conductive inert material is 3 to 5 mm.

[0054] In some preferred embodiments of the present invention, the shape of the thermally conductive inert material is one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, preferably a nest, and more preferably a honeycomb.

[0055] In some embodiments of the present invention, the packing volume ratio of the direct oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.5.

[0056] In some embodiments of the present invention, the packing volume ratio of the deep oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.5.

[0057] In some embodiments of the present invention, the loading volume ratio of the thermally conductive inert material remains constant along the reaction zone.

[0058] The present invention adopts the preferred catalytic oxidation catalyst and thermally conductive inert material graded filling method, which is conducive to more uniform temperature distribution in the reactor, preventing the occurrence of local overheating, thereby improving the long-term stability of the catalytic oxidation catalyst and inhibiting NO x The production of.

[0059] In some embodiments of the present invention, Figure 1 As shown, the system further includes a heat exchanger D, a hydrogen buffer E, a desorption gas buffer F and a flue gas buffer G;

[0060] The heat exchanger D is connected to the feed pipeline 1 and the ammonia conversion device A respectively, and is used to exchange heat between the ammonia-containing raw material from the feed pipeline and the decomposition gas from the ammonia conversion device A;

[0061] The hydrogen buffer E is connected to the deamination device B and the hydrogen purification device C respectively, and is used to store the purified hydrogen and provide purge gas for the deamination device B to blow out the adsorbed ammonia to regenerate the deamination device B. Subsequently, the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A together to perform an ammonia decomposition reaction;

[0062] The desorbed gas buffer F is connected to the catalytic oxidation reaction zone of the hydrogen purification device C and the ammonia conversion device A respectively, and is used to store the desorbed gas of the hydrogen purification device C. Then the desorbed gas enters the catalytic oxidation reaction zone of the ammonia conversion device A, and performs a catalytic oxidation reaction in the catalytic oxidation reaction zone together with the mixture of fresh air and recycled flue gas;

[0063] The flue gas buffer G is respectively connected to the oxidation reaction inlet A3 and the flue gas outlet A4 of the ammonia conversion device A, and is used to store the flue gas discharged from the flue gas outlet A4 of the ammonia conversion device A, and use it as circulating flue gas to enter the catalytic oxidation reaction zone of the ammonia conversion device A through the circulating flue gas outlet pipeline 10 together with the desorbed gas and fresh air from the oxidation reaction inlet A3 to carry out catalytic oxidation reaction.

[0064] In the present invention, Figure 1 As shown, the heat exchanger D is used to exchange heat between the ammonia-containing raw material and the decomposed gas from the ammonia conversion device A to increase the temperature of the ammonia-containing raw material, and the ammonia-containing raw material enters the ammonia conversion device A after heat exchange; the hydrogen buffer E is used to store the purified hydrogen and provide purge gas for the deamination device B to blow out the adsorbed ammonia to regenerate the deamination device B, and then the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A through the TSA regeneration deamination pipeline 3 to perform ammonia decomposition reaction; the desorbed gas buffer F is used to store the desorbed gas of the hydrogen purification device C, and then the desorbed gas is sent to the desorbed gas pipeline 4. 8 enters the catalytic oxidation reaction zone of the ammonia conversion device A, and performs a catalytic oxidation reaction in the catalytic oxidation reaction zone together with a mixture of fresh air from the air pipeline 9 and circulating flue gas from the circulating flue gas outlet pipeline 10, thereby providing heat for the ammonia decomposition reaction in the tube pass; the flue gas buffer G is used to store the flue gas formed by the ammonia conversion device A, and uses it as circulating flue gas to enter the catalytic oxidation reaction zone of the ammonia conversion device A through the circulating flue gas outlet pipeline 10 together with the desorbed gas and the fresh air self-oxidation reaction inlet A3, to perform a catalytic oxidation reaction, thereby providing heat for the ammonia decomposition reaction in the tube pass.

[0065] In the present invention, after the high-purity hydrogen is used to purge the gas deammoniation device, the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A together, and mix with the raw gas to carry out the ammonia decomposition reaction, which not only ensures the utilization efficiency of the reaction raw material ammonia, but also solves the environmental protection problem of residual ammonia emission.

[0066] In some embodiments of the present invention, the catalytic oxidation reaction zone is provided with a guide plate.

[0067] In the present invention, the guide plate is provided to promote air flow and heat exchange.

[0068] In one embodiment of the present invention, the hydrogen purification device C is connected to the deamination device B to provide high-purity hydrogen as a purge gas for the deamination device B to blow out the adsorbed ammonia to regenerate the deamination device B. Subsequently, the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A through the TSA regeneration deamination pipeline 3, and are mixed with the raw gas to carry out an ammonia decomposition reaction.

[0069] The method of the present invention adopts a high-purity hydrogen regeneration deammoniation device, which not only ensures the utilization efficiency of the reaction raw material ammonia, but also solves the environmental protection problem of residual ammonia emission.

[0070] In one embodiment of the present invention, a variable frequency circulation fan is provided at the outlet of the catalytic oxidation reaction zone, and part of the high-temperature flue gas discharged from the high-temperature flue gas outlet is circulated from the reactor outlet to the reactor inlet for inert protection, and the remaining part is discharged through the chimney after heat exchange.

[0071] In the present invention, the combustible concentration at the outlet of the oxidation reaction zone is less than or equal to 1 mg / m 3 .

[0072] In the present invention, liquid ammonia raw material enters the raw material gasification superheater and is heated and gasified to obtain gasified raw material. The gasified raw material enters the ammonia decomposition reaction zone of the ammonia conversion device A after heat exchange in the heat exchanger D, and contacts with the ammonia decomposition catalyst to obtain high-temperature conversion gas. The obtained gas phase material enters the deammonification device B to remove residual ammonia after heat exchange and cooling.

[0073] In the present invention, the deammoniation device B is composed of two TSA adsorption towers and one electric heater. The conversion gas (N2, H2, NH3) enters the adsorption tower in the adsorption state from the bottom, wherein NH3 is adsorbed, and the unadsorbed components are sent to the hydrogen purification device C from the top of the tower. When the TSA adsorption tower is saturated with adsorption, it enters the regeneration process, and the regenerated TSA adsorption tower enters the adsorption process. The regeneration process of the TSA adsorption tower is as follows: (1) Heating regeneration process The regeneration gas from the downstream PSA unit is first heated to 250°C by the heater, and then enters the TSA adsorption tower to heat the drying tower bed until the NH3 adsorbed in the bed is sent to the entrance of the decomposition and hydrogen production zone of the upstream ammonia conversion system. (2) Cooling process The regeneration gas enters the TSA adsorption tower, and the TSA adsorption tower is cooled and flushed until the temperature of the drying tower drops to 40°C, and this TSA adsorption tower can carry out the next adsorption.

[0074] In the present invention, the mixed gas flowing out from the deamination device B is pressurized by a compressor and then enters the hydrogen purification device C for hydrogen purification to obtain high-purity hydrogen and desorbed gas. The pure hydrogen is split, one part is transported as product gas, and the other part is used as regeneration gas for the deamination device B. The desorbed gas from the hydrogen purification device C enters the catalytic oxidation reaction zone of the ammonia conversion device A, and the fresh air and the circulating flue gas are mixed and then enter the catalytic oxidation reaction zone. The catalytic oxidation reaction zone of the shell side of the ammonia decomposition furnace is equipped with a catalytic oxidation catalyst and a heat-conducting inert material, and an oxidation reaction occurs to generate heat to provide heat for the tube side ammonia decomposition reaction.

[0075] A second aspect of the present invention provides a method for producing hydrogen by decomposing ammonia, the method comprising: in the presence of an ammonia decomposition catalyst, subjecting an ammonia-containing raw material to an ammonia decomposition reaction in an ammonia decomposition reaction zone to obtain a decomposed gas; and sequentially performing deammoniation and hydrogen purification on the decomposed gas to obtain hydrogen;

[0076] In the presence of a catalytic oxidation catalyst, air, circulating flue gas and the desorbed gas after the hydrogen is purified are subjected to a catalytic oxidation reaction in a catalytic oxidation reaction zone to provide heat for the ammonia decomposition reaction; the flue gas generated by the catalytic oxidation reaction is discharged from the outlet of the catalytic oxidation reaction zone, and at least a part of the flue gas enters the catalytic oxidation reaction zone as a circulating flue gas to undergo a catalytic oxidation reaction;

[0077] The ammonia decomposition reaction zone is located in the tube side of the shell and tube ammonia decomposition device, and the catalytic oxidation reaction zone is located in the shell side of the shell and tube ammonia decomposition device.

[0078] In the present invention, the ammonia decomposition catalyst is filled in the ammonia decomposition reaction zone.

[0079] In some preferred embodiments, the ammonia decomposition catalyst includes a first metal active component and a first carrier, the first metal active component includes a precious metal component I and a non-precious metal component II; the precious metal component I is Ru and / or Pd, and the non-precious metal component II is selected from one or more of Fe, Co, Ni and Cu.

[0080] More preferably, based on the total weight of the ammonia decomposition catalyst, the content of the precious metal component I is 0.5-5wt%, preferably 0.8-4wt%; the content of the non-precious metal component II is 0.3-20wt%, preferably 1.5-10wt%; and the content of the first carrier is 75-99.2wt%.

[0081] In some preferred embodiments, the particle size of the ammonia decomposition catalyst is 3 to 8 mm.

[0082] In some preferred embodiments, the shape of the ammonia decomposition catalyst is one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, more preferably a nest, and even more preferably a honeycomb.

[0083] In some preferred embodiments, in the ammonia decomposition catalyst, the precious metal component I is Pd and Ru, the non-precious metal component II is Fe, and the first carrier is γ-Al2O3.

[0084] Preferably, the molar ratio of Pd:Ru:Fe is 1:1-2:3-6.

[0085] In the present invention, the catalytic oxidation catalyst is filled in the catalytic oxidation reaction zone.

[0086] In some preferred embodiments, the catalytic oxidation catalyst includes a second metal active component and a second carrier, the second metal active component includes a precious metal component III and a non-precious metal component IV; the precious metal component III is Pt and / or Pd, and the non-precious metal component IV is selected from one or more of Mn, Mg, Fe, Co, Ni, Cu, Ag, Ce, W, Cu, Ca and La.

[0087] More preferably, based on the total weight of the catalytic oxidation catalyst, the content of the noble metal component III is 0.01-1 wt%, the content of the non-noble metal component IV is 0.03-20 wt%, and the content of the second carrier is 79-99.96 wt%.

[0088] In some preferred embodiments, the particle size of the catalytic oxidation catalyst is 3 to 5 mm.

[0089] In some preferred embodiments, the catalytic oxidation catalyst is in the shape of one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, more preferably a nest, and further preferably a honeycomb. The honeycomb catalyst has better heat dissipation and controllable reaction effect.

[0090] In one embodiment of the present invention, the catalytic oxidation reaction specifically comprises:

[0091] First, a direct oxidation reaction is carried out in the presence of a direct oxidation catalyst; and then a deep oxidation reaction is carried out in the presence of a deep oxidation catalyst.

[0092] In the present invention, a mixture of a direct oxidation catalyst and a thermally conductive inert material is filled in the direct oxidation zone; and a mixture of a deep oxidation catalyst and a thermally conductive inert material is filled in the deep oxidation zone.

[0093] In the present invention, by optimizing the graded filling method and optimizing the catalytic oxidation catalyst in the catalytic oxidation reaction zone, the reaction controllability can be further improved, the combustible content in the tail gas and the bed temperature distribution can be reduced, and the overall operation stability and conversion effect can be improved.

[0094] In some preferred embodiments, based on the total weight of the direct oxidation catalyst, the content of the noble metal component III is 0.01-0.04 wt%, and the content of the non-noble metal component IV is 0.05-10 wt%.

[0095] More preferably, in the direct oxidation catalyst, the noble metal component III is Pt, the non-noble metal component IV is Mn, and the second carrier is TiO2 and / or Al2O3.

[0096] Further preferably, the molar ratio of Pt:Mn is 1:1 to 1:8;

[0097] In some preferred embodiments, based on the total weight of the deep oxidation catalyst, the content of the precious metal component III is 0.05-0.8 wt%, and the content of the non-precious metal component IV is 0.05-15 wt%.

[0098] More preferably, in the deep oxidation catalyst, the precious metal component III is Pt and Pd, the non-precious metal component IV is Mn and W, and the second carrier is one or more of CeO2, TiO2 and Al2O3.

[0099] More preferably, the molar ratio of Pt:Pd:Mn:W is 1-2:1:1-8:1-6.

[0100] In some preferred embodiments, the thermally conductive inert material is selected from one or more of SiC, SiO2, AlN, BN and Al2O3, preferably SiC.

[0101] In some preferred embodiments, the particle size of the thermally conductive inert material is 3 to 5 mm.

[0102] In some preferred embodiments, the shape of the thermally conductive inert material is one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, preferably a nest, and more preferably a honeycomb.

[0103] In some preferred embodiments, the packing volume ratio of the direct oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.5.

[0104] In some preferred embodiments, the packing volume ratio of the deep oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.5.

[0105] In some embodiments of the present invention, the loading volume ratio of the thermally conductive inert material remains constant along the reaction zone.

[0106] In one embodiment of the present invention, the pressure of the catalytic oxidation reaction zone is 0.01-0.1 MPa, and the temperature is 0-580°C.

[0107] In the present invention, the pressure of the direct oxidation reaction is 0.01-0.1 MPa and the temperature is 0-580°C.

[0108] In the present invention, the pressure of the deep oxidation reaction is 0.01-0.1 MPa and the temperature is 0-580° C. In one embodiment of the present invention, the temperature at the inlet of the catalytic oxidation reaction zone is 10-400° C., preferably 200-380° C.

[0109] In one embodiment of the present invention, the oxygen content at the inlet of the catalytic oxidation reaction zone is less than 5% by volume, and the oxygen content at the outlet is 0.5 to 1.5% by volume;

[0110] In one embodiment of the present invention, the oxygen content is regulated by the flow rates of air and circulating flue gas.

[0111] In the present invention, the amount of desorbed gas is adjusted by the outlet temperature of the ammonia decomposition reaction zone.

[0112] In the present invention, the pressure of the ammonia decomposition reaction zone is 0.5-2 MPa and the temperature is 450-650°C.

[0113] In one embodiment of the present invention, the method further includes: part of the hydrogen enters the deamination device B through the purge gas pipeline 7 to provide purge gas for the deamination device B to blow out the adsorbed ammonia to regenerate the deamination device B; then the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A through the regeneration deamination pipeline 3 to carry out an ammonia decomposition reaction.

[0114] In one embodiment of the present invention, the method further comprises: exchanging heat between the decomposed gas and the ammonia-containing raw material to increase the temperature of the ammonia-containing raw material.

[0115] In the present invention, after the high-purity hydrogen is used to purge the gas deammoniation device, the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A together to carry out the ammonia decomposition reaction, which not only ensures the utilization efficiency of the reaction raw material ammonia, but also solves the environmental protection problem of residual ammonia emission.

[0116] According to a particularly preferred embodiment of the present invention, Figures 1 to 4 As shown, a method for producing hydrogen by decomposing ammonia is provided, which specifically comprises the following steps:

[0117] like Figure 1As shown, the ammonia-containing raw material enters the heat exchanger D through the feed pipeline 1, and the raw material gas is heat-exchanged with the decomposition gas from the ammonia conversion device A to increase the temperature of the ammonia-containing raw material, and the ammonia-containing raw material is preheated to 450-480°C to gasify the liquid ammonia therein into ammonia gas. The preheated raw material enters the ammonia decomposition reaction zone of the ammonia conversion device A from the ammonia raw material inlet A1, and in the presence of an ammonia decomposition catalyst, an ammonia decomposition reaction is carried out to obtain decomposition gas, which is discharged from the decomposition gas outlet A2; wherein, the ammonia conversion device A is a shell-and-tube structure, the tube side is the ammonia decomposition reaction zone, which is provided with an ammonia raw material inlet A1 and a decomposition gas outlet A2, and the shell side is the catalytic oxidation reaction zone, which is provided with an oxidation reaction inlet A3 and a flue gas outlet A4, and the distribution of the tube side and the shell side is as shown in FIG. Figure 2 to Figure 4 As shown;

[0118] After the decomposed gas obtained above is heat-exchanged with the raw material, it enters the deamination device B through the decomposed gas pipeline 4 for deamination, and then the decomposed gas after deamination enters the hydrogen purification device C through the rough deamination pipeline 5 for hydrogen purification to obtain high-purity hydrogen; the high-purity hydrogen enters the hydrogen buffer E through the high-purity hydrogen pipeline 6 for storing the obtained high-purity hydrogen, and the hydrogen in the hydrogen buffer E outputs high-purity hydrogen through the hydrogen product pipeline 2, and at the same time, part of the high-purity hydrogen enters the deamination device B through the purge gas pipeline 7 to provide purge gas for the deamination device B, blow out the adsorbed ammonia, and regenerate the deamination device B; then the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device A through the regeneration deamination pipeline 3, and are mixed with the raw material gas after heat exchange to carry out ammonia decomposition reaction;

[0119] The hydrogen purification device C is desorbed, and the desorbed gas enters the desorbed gas buffer F, which is used to store the desorbed gas of the hydrogen purification device C. Part of the desorbed gas is merged with the fresh air from the air pipeline 9 and the circulating flue gas from the circulating flue gas outlet pipeline 10 through the desorbed gas pipeline 8 and then enters the catalytic oxidation reaction zone of the ammonia conversion device A from the oxidation reaction inlet A3 to perform a catalytic oxidation reaction, thereby providing heat for the ammonia decomposition reaction in the tube pass;

[0120] The flue gas generated by the above-mentioned catalytic oxidation reaction is discharged from the flue gas outlet A4 of the ammonia conversion device A. Part of the flue gas is discharged through the flue gas emission pipeline 12, and part of the flue gas enters the flue gas buffer G through the circulating flue gas inlet pipeline 11. The flue gas buffer G is used to store the flue gas formed by the ammonia conversion device A, and use it as circulating flue gas through the circulating flue gas outlet pipeline 10 and the desorbed gas and fresh air self-oxidation reaction inlet A3 to enter the catalytic oxidation reaction zone of the ammonia conversion device A for catalytic oxidation reaction.

[0121] The present invention will be described in detail below through examples.

[0122] In the following examples and comparative examples, unless otherwise specified, all raw materials used were commercially available.

[0123] In the following examples, the composition of each gas stream was measured by standard methods such as chromatography or infrared spectroscopy.

[0124] Residual ammonia content: The residual ammonia content was determined by Fourier transform infrared spectrometer.

[0125] Hydrogen content: measured by Agilent 8890 gas chromatograph equipped with PLOT Q, 5A molecular sieve, HP-PLOT, Al2O3 column and FID / TCD detector.

[0126] Preparation Example 1

[0127] The preparation method of the direct oxidation catalyst is as follows:

[0128] Step 1: Pseudo-boehmite, titanium oxide and cellulose in a mass ratio of 95.5:1.5:3 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a nest-shaped carrier of Φ3-5 mm is prepared and calcined to obtain a nest-shaped TiO2 / Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0129] Step 2: Using a mixed solution of chloroplatinic acid and manganese nitrate as the impregnation solution, wherein the Pt:Mn metal molar ratio is 1:5, under room temperature conditions, the Pt and Mn active components are loaded by an equal volume impregnation method. After washing, filtering and separation, the mixture is dried at 120°C for 12 hours and calcined at 500°C in an air environment for 2 hours to obtain the S1 catalyst. The Pt content is 0.01% by weight based on the weight of the catalytic oxidation catalyst.

[0130] Preparation Example 2

[0131] The preparation method of the deep oxidation catalyst is as follows:

[0132] Step 1: Pseudo-boehmite, titanium oxide, cerium oxide and cellulose in a mass ratio of 95.5:2.5:1:1.5 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a nest-shaped carrier of Φ3-5 mm is prepared and calcined to obtain a nest-shaped CeO2 / TiO2 / Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0133] Step 2: Using a mixed solution of chloroplatinic acid, palladium nitrate, manganese nitrate and ammonium tungstate as an impregnation solution, wherein the metal molar ratio of Pt:Pd:Mn:W is 1:1:5:3, and at room temperature, the Pt / Pd / Mn / W components are loaded by an equal volume impregnation method, washed, filtered, and separated, and then dried at 120°C for 12 hours, and calcined at 600°C for 2 hours in an air environment to obtain the S2 catalyst. Based on the weight of the catalytic oxidation catalyst, the Pt content is 0.5% by weight.

[0134] Preparation Example 3

[0135] The preparation method of the ammonia decomposition catalyst is as follows:

[0136] Step 1: Pseudo-boehmite and cellulose in a mass ratio of 95.5:4.5 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a nest-shaped carrier of Φ3-5 mm is prepared and calcined to obtain a nest-shaped γ-Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0137] Step 2: Using a mixed solution of palladium nitrate, ruthenium nitrate and iron nitrate as an impregnation solution, wherein the metal molar ratio of Pd:Ru:Fe is 1:1:5, and at room temperature, the Pd / Ru / Fe components are loaded by an equal volume impregnation method, washed, filtered, and separated, and then dried at 120°C for 12 hours, and calcined at 500°C for 2 hours in an air environment to obtain the S3 catalyst. The Pd content is 0.5% by weight based on the weight of the ammonia decomposition catalyst.

[0138] Preparation Example 4

[0139] The preparation method of the direct oxidation catalyst is as follows:

[0140] Step 1: Pseudo-boehmite, titanium oxide and cellulose in a mass ratio of 95.5:1.5:3 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a spherical carrier of Φ3-5 mm is prepared and calcined to obtain a spherical TiO2 / Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0141] Step 2: Using a mixed solution of chloroplatinic acid and manganese nitrate as the impregnation solution, wherein the Pt:Mn metal molar ratio is 1:5, under room temperature conditions, the PtMn active component is loaded by an equal volume impregnation method. After washing, filtering and separation, it is dried at 120°C for 12 hours and calcined at 500°C for 2 hours in an air environment to obtain the S4 catalyst. Based on the weight of the catalytic oxidation catalyst, the Pt content is 0.01% by weight.

[0142] Preparation Example 5

[0143] The preparation method of the deep oxidation catalyst is as follows:

[0144] Step 1: Pseudo-boehmite, titanium oxide, cerium oxide and cellulose in a mass ratio of 95.5:2.5:1:1.5 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a nest-shaped carrier of Φ3-5 mm is prepared and calcined to obtain a nest-shaped CeO2 / TiO2 / Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0145] Step 2: Using a mixed solution of chloroplatinic acid, palladium nitrate and manganese nitrate as an impregnation solution, wherein the metal molar ratio of Pt:Pd:Mn is 1:1:5, and at room temperature, the Pt / Pd / Mn components are loaded by an equal volume impregnation method, washed, filtered, separated, dried at 120°C for 12 hours, and calcined at 600°C for 2 hours in an air environment to obtain the S5 catalyst. The Pt content is 0.5% by weight based on the weight of the catalytic oxidation catalyst.

[0146] Preparation Example 6

[0147] The preparation method of the deep oxidation catalyst is as follows:

[0148] Step 1: Pseudo-boehmite, titanium oxide, cerium oxide and cellulose in a mass ratio of 95.5:2.5:1:1.5 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a spherical carrier of Φ3-5 mm is prepared and calcined to obtain a spherical CeO2 / TiO2 / Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0149] Step 2: Using a mixed solution of chloroplatinic acid, palladium nitrate, manganese nitrate and ammonium tungstate as an impregnation solution, wherein the metal molar ratio of Pt:Pd:Mn:W is 1:1:5:3, and at room temperature, the Pt / Pd / Mn / W components are loaded by an equal volume impregnation method, washed, filtered, and separated, and then dried at 120°C for 12 hours, and calcined at 600°C for 2 hours in an air environment to obtain the S6 catalyst. The Pt content is 0.5% by weight based on the weight of the catalytic oxidation catalyst.

[0150] Preparation Example 7

[0151] The preparation method of the ammonia decomposition catalyst is as follows:

[0152] Step 1: Pseudo-boehmite and cellulose in a mass ratio of 95.5:4.5 are mixed and ball-milled until the particle size is less than 320 mesh, and then water is added to mix evenly, and then a spherical carrier of Φ3-5 mm is prepared and calcined to obtain a spherical γ-Al2O3 carrier with a specific surface area of ​​≥150m 2 / g, strength reaches 150N / grain or more;

[0153] Step 2: Using a mixed solution of palladium nitrate, ruthenium nitrate and iron nitrate as an impregnation solution, wherein the metal molar ratio of Pd:Ru:Fe is 1:1:5, and at room temperature, the Pd / Ru / Fe components are loaded by an equal volume impregnation method, washed, filtered, and separated, and then dried at 120°C for 12 hours, and calcined at 500°C for 2 hours in an air environment to obtain the S7 catalyst. The Pd content is 0.5% by weight based on the weight of the ammonia decomposition catalyst.

[0154] Test Example 1

[0155] The catalytic oxidation performance of the catalysts S1, S2, S4, S5 and S6 prepared in the above preparation examples was evaluated respectively. The reaction was carried out in a pressurized fixed bed continuous flow reactor (Φ19 mm). The catalyst loading was 5 g. The reaction conditions were: 450° C., 5 kPa, 1% hydrogen volume fraction, 0.8% oxygen mass fraction, 0.1% ammonia volume fraction, and the rest nitrogen. The gas hourly space velocity was 10000 h -1 The unreacted hydrogen product was analyzed online by a 490-type chromatograph with a TCD detector, and the residual ammonia was tested and analyzed by an online infrared analyzer. The results are shown in Table 1.

[0156] Table 1

[0157] catalyst Residual ammonia content Hydrogen content S1 <![CDATA[0.8mg / m 3 ]]> <![CDATA[0mg / m 3 ]]> S2 <![CDATA[0.02mg / m 3 ]]> <![CDATA[0mg / m 3 ]]> S4 <![CDATA[58mg / m 3 ]]> <![CDATA[0mg / m 3 ]]> S5 <![CDATA[4mg / m 3 ]]> <![CDATA[0mg / m 3 ]]> S6 <![CDATA[44mg / m 3 ]]> <![CDATA[0mg / m 3 ]]>

[0158] It can be seen from the results in Table 1 that the residual ammonia content when using S1 and S2 catalysts for catalytic oxidation reactions is significantly lower than that of S4 and S5 catalysts, indicating that S1 and S2 catalysts have better catalytic oxidation effects, which not only ensure the utilization efficiency of the reaction raw material ammonia, but also solve the environmental protection problem of residual ammonia emissions.

[0159] Test Example 2

[0160] The S3 and S7 catalysts prepared in the above preparation examples were evaluated for their performance in hydrogen production by decomposing ammonia. The reaction was carried out in a pressurized fixed bed continuous flow reactor (Φ19 mm). The catalyst loading was 5 g. The reaction conditions were: 450°C, 0.1 MPa, 5% hydrogen gas volume fraction, 50% ammonia gas volume fraction, and the rest nitrogen. The gas hourly space velocity was 2400 h -1 The residual ammonia after the reaction was tested and analyzed by an online infrared analyzer, and the results are shown in Table 2.

[0161] Table 2

[0162] catalyst Residual ammonia content S3 <![CDATA[18mg / m 3 ]]> S7 <![CDATA[472mg / m 3 ]]>

[0163] It can be seen from the results in Table 2 that the residual ammonia content when the S3 catalyst is used for the ammonia decomposition reaction is significantly lower than that of the S7 catalyst, indicating that the S3 catalyst has a better ammonia decomposition hydrogen production effect, which not only ensures the utilization efficiency of the reaction raw material ammonia, but also solves the environmental protection problem of residual ammonia emissions.

[0164] Example

[0165] Use Figure 1 The process flow shown in the figure uses the catalysts S1 to S7 prepared in the above preparation examples in combination, adopts catalytic oxidation reaction as the heat source, and the catalytic oxidation catalyst filling volume in the catalytic oxidation reaction zone is 0.35m 3 , the thermally conductive inert material SiC filling volume is 0.8m 3 , reaction outlet pressure 5kPa, volume space velocity 8500~12000h -1 The inner diameter of the reaction tube in the ammonia decomposition reaction zone is 48 mm, the number of tubes is 10, the total length of each tube is 10 m, and the catalyst loading volume is 0.2 m 3 , reaction pressure 0.1MPa, outlet temperature 450℃.

[0166] After the ammonia conversion reaction unit is heated to 450°C by an electric heater, the ammonia flow rate in the ammonia decomposition reaction zone is 24kg / h to 36kg / h and the reaction is started at a light load. The mixed material of the desorbed gas enters the catalytic oxidation reactor, and the circulating air flow rate in the catalytic oxidation reaction zone is controlled to be 3500Nm 3 / h, the oxygen content at the tube outlet is between 0.5 and 1.5 volume %. Gradually adjust to the full load of 120kg / h for the ammonia decomposition hydrogen production system, adjust the PSA yield to make the hydrogen product purity qualified, and the TSA regeneration hydrogen flow rate is 20Nm 3 / h, the outlet temperature of the stable ammonia decomposition reaction is 450°C. The residual ammonia content of the key stream ammonia conversion gas pipeline 4 and the residual ammonia content and combustible content of the flue gas emission pipeline 12 of the system were tested respectively, and the corresponding results are shown in Figure 3.

[0167] Table 3

[0168]

[0169] From the results in Table 3, it can be seen that by using the S1, S2 and S3 catalysts in combination for ammonia decomposition to produce hydrogen, the residual ammonia content is significantly lower than that of other combinations. The method of the present invention not only ensures the utilization efficiency of the reaction raw material ammonia, but also solves the environmental protection problem of residual ammonia emissions. Comparing No. 1, 5 and 6, it can be seen that the shell structure has a greater impact on the performance of the deep catalytic oxidant. At the same time, the deep oxidation reaction has a significant impact on whether the catalytic oxidation unit emissions are qualified, and has a weak impact on the reaction effect of the ammonia decomposition unit; comparing No. 4, 7 and 8, it can be seen that the direct oxidation zone reaction effect affects the heating effect on the overall reaction of ammonia decomposition, and the introduction of the component tungsten can effectively increase the reaction depth.

[0170] Comparative Example

[0171] The ammonia decomposition reaction was carried out according to the method of Example 1, except that the commonly used electric heating furnace structure was used as the ammonia conversion device, and no catalytic oxidation reaction was carried out. The required external heat source was electric heating. The residual ammonia content of stream 4 was 64 mg / m 3 , residual ammonia content in stream 8 is 374 mg / m 3 , hydrogen content of stream 8 is 29209mg / m 3 .

[0172] As can be seen from the above, by adopting the shell and tube ammonia conversion device of the present invention, the entire hydrogen production process does not need to add additional external heat sources and equipment, and has higher energy efficiency. At the same time, the utilization efficiency of the reaction raw material ammonia is guaranteed, and the environmental protection problem of residual ammonia emissions is solved.

[0173] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An ammonia decomposition hydrogen production system, characterized in that: The system comprises an ammonia conversion device, a deamination device and a hydrogen purification device; wherein the ammonia conversion device is a shell-and-tube structure, the tube side is an ammonia decomposition reaction zone, provided with an ammonia raw material inlet and a decomposition gas outlet, and the shell side is a catalytic oxidation reaction zone, provided with an oxidation reaction inlet and a flue gas outlet; the decomposition gas outlet is connected to the deamination device for removing residual ammonia; the deamination device is connected to the hydrogen purification device for purifying hydrogen; the oxidation reaction inlet is connected to the hydrogen purification device for passing the desorbed gas of the hydrogen purification device into the catalytic oxidation reaction zone, and the oxidation reaction inlet is also connected to the flue gas outlet for passing the circulating flue gas from the flue gas outlet into the catalytic oxidation reaction zone through the oxidation reaction inlet.

2. The system according to claim 1, wherein: The ammonia decomposition reaction zone is filled with an ammonia decomposition catalyst; Preferably, the ammonia decomposition catalyst comprises a first metal active component and a first carrier, the first metal active component comprises a precious metal component I and a non-precious metal component II; the precious metal component I is Ru and / or Pd, and the non-precious metal component II is selected from one or more of Fe, Co, Ni and Cu; More preferably, based on the total weight of the ammonia decomposition catalyst, the content of the precious metal component I is 0.5-5wt%, preferably 0.8-4wt%; the content of the non-precious metal component II is 0.3-20wt%, preferably 1.5-10wt%; the content of the first carrier is 75-99.2wt%; Preferably, the particle size of the ammonia decomposition catalyst is 3 to 8 mm; Preferably, the ammonia decomposition catalyst has a shape of one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, more preferably a nest, and even more preferably a honeycomb.

3. The system according to claim 2, wherein: In the ammonia decomposition catalyst, the noble metal component I is Pd and Ru, the non-noble metal component II is Fe, and the first carrier is γ-Al2O3; Preferably, the molar ratio of Pd:Ru:Fe is 1:1-2:3-6.

4. The system according to any one of claims 1 to 3, wherein: The catalytic oxidation reaction zone is filled with a catalytic oxidation catalyst; Preferably, the catalytic oxidation catalyst comprises a second metal active component and a second carrier, the second metal active component comprises a noble metal component III and a non-noble metal component IV; the noble metal component III is Pt and / or Pd, and the non-noble metal component IV is selected from one or more of Mn, Mg, Fe, Co, Ni, Cu, Ag, Ce, W, Cu, Ca and La; More preferably, based on the total weight of the catalytic oxidation catalyst, the content of the precious metal component III is 0.01 to 1 wt%, the content of the non-precious metal component IV is 0.03 to 20 wt%, and the content of the second carrier is 79 to 99.96 wt%; Preferably, the particle size of the catalytic oxidation catalyst is 3 to 5 mm; Preferably, the catalytic oxidation catalyst has a shape of one or more of sphere, cloverleaf, Raschig ring, and nest, more preferably a nest, and even more preferably a honeycomb.

5. The system according to claim 4, wherein: The catalytic oxidation reaction zone includes a direct oxidation zone and a deep oxidation zone, wherein the direct oxidation zone is located upstream of the catalytic oxidation reaction zone; the deep oxidation zone is located downstream of the catalytic oxidation reaction zone; Preferably, the ratio of the layer height of the direct oxidation zone to the layer height of the deep oxidation zone is 1 to 2:1; Preferably, the direct oxidation zone is filled with a mixture of a direct oxidation catalyst and a thermally conductive inert material; and the deep oxidation zone is filled with a mixture of a deep oxidation catalyst and a thermally conductive inert material.

6. The system according to claim 5, wherein: Based on the total weight of the direct oxidation catalyst, the content of the precious metal component III is 0.01-0.04wt%, and the content of the non-precious metal component IV is 0.05-10wt%; preferably, in the direct oxidation catalyst, the precious metal component III is Pt, the non-precious metal component IV is Mn, and the second carrier is TiO2 and Al2O3; more preferably, the molar ratio of Pt:Mn is 1:1-1:8; And / or, based on the total weight of the deep oxidation catalyst, the content of the precious metal component III is 0.05-0.8wt%, and the content of the non-precious metal component IV is 0.05-15wt%; preferably, in the deep oxidation catalyst, the precious metal component III is Pt and Pd, the non-precious metal component IV is Mn and W, and the second carrier is CeO2, TiO2 and Al2O3; more preferably, the molar ratio of Pt:Pd:Mn:W is 1-2:1:1-8:1-6.

7. The system according to claim 5 or 6, wherein: The thermally conductive inert material is selected from one or more of SiC, SiO2, AlN, BN and Al2O3, preferably SiC; and / or, the particle size of the thermally conductive inert material is 3 to 5 mm; And / or, the shape of the thermally conductive inert material is one or more of a sphere, a cloverleaf, a Raschig ring, and a nest, preferably a nest, and more preferably a honeycomb; and / or, the packing volume ratio of the direct oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.5; And / or, the packing volume ratio of the deep oxidation catalyst to the thermally conductive inert material is 1:6 to 1:1, preferably 1:5 to 1:1.

5.

8. The system according to any one of claims 1 to 7, wherein: The system further comprises a heat exchanger, a hydrogen buffer, a desorption gas buffer and a flue gas buffer; the heat exchanger is respectively connected to the feed pipeline and the ammonia conversion device, and is used for exchanging heat between the ammonia-containing raw material from the feed pipeline and the decomposition gas from the ammonia conversion device; the hydrogen buffer is respectively connected to the deamination device and the hydrogen purification device, and is used for storing purified hydrogen and providing purge gas for the deamination device to blow out the adsorbed ammonia to regenerate the deamination device, and then the hydrogen and the blown ammonia enter the ammonia decomposition reaction zone of the ammonia conversion device together to carry out ammonia decomposition reaction; the desorption gas buffer is respectively connected to the hydrogen purification device and the desorption gas buffer. The device and the catalytic oxidation reaction zone of the ammonia conversion device are used to store the desorbed gas of the hydrogen purification device, and then the desorbed gas enters the catalytic oxidation reaction zone of the ammonia conversion device, and performs a catalytic oxidation reaction in the catalytic oxidation reaction zone together with the mixture of fresh air and circulating flue gas, so as to provide heat for the ammonia decomposition reaction in the tube; the flue gas buffer is respectively connected to the oxidation reaction inlet and the flue gas outlet of the ammonia conversion device, and is used to store the flue gas discharged from the flue gas outlet of the ammonia conversion device, and uses it as the circulating flue gas, the desorbed gas and the fresh air to enter the catalytic oxidation reaction zone of the ammonia conversion device from the oxidation reaction inlet to perform a catalytic oxidation reaction; And / or, the catalytic oxidation reaction zone is provided with a guide plate.

9. An ammonia decomposition reaction ammonia decomposition method for producing hydrogen, characterized in that: The method comprises: in the presence of an ammonia decomposition catalyst, subjecting an ammonia-containing raw material to an ammonia decomposition reaction in an ammonia decomposition reaction zone to obtain a decomposed gas; and sequentially performing deammoniation and hydrogen purification on the decomposed gas to obtain hydrogen; In the presence of a catalytic oxidation catalyst, air, circulating flue gas and the desorbed gas after the hydrogen is purified are subjected to a catalytic oxidation reaction in a catalytic oxidation reaction zone to provide heat for the ammonia decomposition reaction; the flue gas generated by the catalytic oxidation reaction is discharged from the outlet of the catalytic oxidation reaction zone, and at least a part of the flue gas enters the catalytic oxidation reaction zone as a circulating flue gas to undergo a catalytic oxidation reaction; The ammonia decomposition reaction zone is located in the tube side of the shell and tube ammonia decomposition device, and the catalytic oxidation reaction zone is located in the shell side of the shell and tube ammonia decomposition device.

10. The method according to claim 9, wherein: The catalytic oxidation reaction specifically comprises: Firstly, a direct oxidation reaction is carried out in the presence of a direct oxidation catalyst; and then a deep oxidation reaction is carried out in the presence of a deep oxidation catalyst; Preferably, based on the total weight of the direct oxidation catalyst, the content of the precious metal component III is 0.01-0.04wt%, and the content of the non-precious metal component IV is 0.05-10wt%; more preferably, in the direct oxidation catalyst, the precious metal component III is Pt, the non-precious metal component IV is Mn, and the second carrier is TiO2 and / or Al2O3; further preferably, the molar ratio of Pt:Mn is 1:1-1:8; Preferably, based on the total weight of the deep oxidation catalyst, the content of the precious metal component III is 0.05-0.8wt%, and the content of the non-precious metal component IV is 0.05-15wt%; more preferably, in the deep oxidation catalyst, the precious metal component III is Pt and Pd, the non-precious metal component IV is Mn and W, and the second carrier is one or more of CeO2, TiO2 and Al2O3; further preferably, the molar ratio of Pt:Pd:Mn:W is 1-2:1:1-8:1-6.

11. The method according to claim 9 or 10, wherein: The pressure of the catalytic oxidation reaction zone is 0.01-0.1 MPa and the temperature is 0-580°C; and / or, the temperature at the inlet of the catalytic oxidation reaction zone is 10 to 400° C., preferably 200 to 380° C.; and / or, the oxygen content at the inlet of the catalytic oxidation reaction zone is less than 5% by volume, and the oxygen content at the outlet is 0.5 to 1.5% by volume; Preferably, the oxygen content is regulated by the flow rates of air and circulating flue gas.

12. The method according to any one of claims 9 to 11, wherein: The method further comprises: using part of the hydrogen as a purge gas for the deamination device to blow out the adsorbed ammonia to achieve regeneration of the deamination device; then the hydrogen and the blown out ammonia enter the ammonia decomposition reaction zone together to perform an ammonia decomposition reaction.

13. The method according to any one of claims 9 to 12, wherein: The method further comprises: exchanging heat between the decomposed gas and the ammonia-containing raw material to increase the temperature of the ammonia-containing raw material.

14. A catalytic oxidation catalyst, characterized in that: The catalytic oxidation catalyst includes a second metal active component and a second carrier, the second metal active component includes a precious metal component III and a non-precious metal component IV; the precious metal component III is Pt and / or Pd, and the non-precious metal component IV is selected from one or more of Mn, Mg, Fe, Co, Ni, Cu, Ag, Ce, W, Cu, Ca and La.

15. The catalytic oxidation catalyst according to claim 14, wherein: Based on the total weight of the catalytic oxidation catalyst, the content of the precious metal component III is 0.01-1wt%, the content of the non-precious metal component IV is 0.03-20wt%, and the content of the second carrier is 79-99.96wt%; And / or, the particle size of the catalytic oxidation catalyst is 3 to 5 mm; And / or, the catalytic oxidation catalyst has a shape of one or more of spherical, clover-leaf, Raschig ring, and nest, more preferably a nest, and even more preferably a honeycomb.

16. A method for treating a gas containing low concentrations of ammonia and hydrogen, characterized in that: The treatment method comprises: contacting a gas containing low concentrations of ammonia and hydrogen with the catalytic oxidation catalyst described in claim 14 or 15 to perform a catalytic oxidation reaction to obtain a purified gas.

17. The processing method according to claim 16, wherein: The concentration of ammonia in the gas containing low concentration ammonia and hydrogen is not more than 1000 mg / m 3 ; And / or, the pressure of the catalytic oxidation reaction is 0.01-0.1 MPa and the temperature is 0-580° C.; and / or, the oxygen content of the catalytic oxidation reaction is less than 5% by volume, and the oxygen content after the reaction is 0.5 to 1.5% by volume; And / or, the concentration of ammonia in the purified gas is less than 1 mg / m 3 .

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