Product continuous production method and device for synthesizing ammonia through chemical looping circulation

Abstract

The invention discloses a continuous product output method and device for synthesizing ammonia through chemical looping circulation. The method comprises the following steps: heating more than two chemical looping reactors connected in parallel to a reaction temperature; carbon dioxide and hydrogen are introduced or only hydrogen is introduced into the corresponding reactor through the first gas inlet passage of one gas selection valve, and nitrogen and hydrogen are introduced or only nitrogen is introduced into the corresponding reactor through the second gas inlet passages of the other gas selection valves; and when the ammonia gas concentration in the gas discharged by the reactor for producing ammonia gas is less than or equal to a threshold value, replacing the passage of the corresponding gas selection valve, and replacing the passage of the gas selection valve corresponding to the other reactor, and repeating the steps in sequence. According to the present invention, the gas introduced into the reactor is switched through the gas selection valve, such that the in-situ regeneration of the catalyst in the reactor and the ammonia gas output circulation are achieved, the flow of the catalyst in different reactors is avoided, and the ammonia synthesis efficiency and the ammonia synthesis sustainability are improved; the reactor is simple in structure, convenient to operate and small in equipment investment.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia synthesis, and in particular to a method and device for continuously producing products for chemical chain cycle ammonia synthesis. Background Art

[0002] Ammonia is one of the most important basic chemicals in the fields of agriculture, chemical industry, energy, etc. Its synthesis methods include the traditional Habor-Bosch ammonia synthesis method and the chemical looping method. Due to the limitations of kinetics and thermodynamics, the Habor-Bosch ammonia synthesis method consumes huge amounts of energy, and its efficiency and sustainability are relatively low. Chemical looping is a process in which a chemical reaction is completed in multiple steps through a chemical medium, and has potential application value in the fields of catalyst regeneration and fossil energy conversion. This method uses a specific carrier (such as an oxygen carrier or a nitrogen carrier, etc.) as a medium, which is circulated between different reactors to achieve the transmission of oxygen or nitrogen elements and the conduct of chemical reactions. Relying on mature circulating fluidized bed or moving bed technology, it can also achieve a continuous industrial production process similar to a steady-state reaction, and is a potential industrial ammonia synthesis process.

[0003] The existing chemical chain cycle ammonia synthesis method mainly uses reactors such as circulating fluidized beds or moving beds to allow the catalyst to flow in different reactors (i.e., under different atmospheres) to achieve a cycle of catalyst reaction and regeneration. These reactors have problems such as complex operation and large equipment investment. Frequent flow replacement of catalysts for regeneration not only increases operational complexity, but also reduces production efficiency. Therefore, how to achieve in-situ regeneration of the catalyst, achieve the output of continuous flow of high-concentration products, and improve the efficiency and sustainability of ammonia synthesis are the main problems facing the current chemical chain cycle ammonia synthesis. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method and device for continuous production of products for chemical chain cycle ammonia synthesis. More than two chemical chain reactors are arranged in parallel, and the gas introduced into the reactor is switched by a two-inlet and one-outlet gas selection valve, thereby replacing the gas atmosphere in the reactor, realizing in-situ regeneration of the catalyst in the reactor and production of ammonia (NH3). Multiple reactors alternately perform NH3 production and in-situ regeneration of the catalyst in turn, realizing continuous flow of high-concentration NH3 production, and improving the efficiency and sustainability of ammonia synthesis.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for continuously producing products for chemical chain cycle ammonia synthesis, comprising the following steps:

[0006] S1. Heating two or more chemical chain reactors arranged in parallel to a reaction temperature, wherein the gas inlet end of each reactor is connected to a corresponding two-inlet-one-outlet gas selection valve, and the gas outlet end is connected to a corresponding one-inlet-two-outlet gas selection valve;

[0007] The first air inlet passage of the two-inlet-one-outlet gas selection valve is connected to a carbon dioxide and hydrogen gas source or is only connected to a hydrogen gas source, and the second air inlet passage is connected to a nitrogen and hydrogen gas source or is only connected to a nitrogen gas source; the first air outlet passage of the one-inlet-two-outlet gas selection valve is used to discharge exhaust gas, and the second air outlet passage is used to discharge and collect ammonia;

[0008] S2, a mixed gas of carbon dioxide and hydrogen or only hydrogen is introduced into the corresponding reactor through the first gas inlet passage of one of the two-inlet-one-outlet gas selection valves, and the catalyst carrying nitrogen species in the reactor removes the surface nitrogen species to produce ammonia, which is discharged and collected through the second gas outlet passage of the corresponding one-inlet-two-outlet gas selection valve; at the same time, a mixed gas of nitrogen and hydrogen or only nitrogen is introduced into the corresponding reactor through the second gas inlet passages of the other two-inlet-one-outlet gas selection valves, and the catalyst in the reactor is regenerated, and the waste gas is discharged through the first gas outlet passage of the corresponding one-inlet-two-outlet gas selection valve;

[0009] S3. When the ammonia concentration in the gas discharged from the reactor producing ammonia is less than or equal to the threshold value, the corresponding inlet passage of the two-inlet-one-outlet gas selection valve and the outlet passage of the one-inlet-two-outlet gas selection valve are replaced to regenerate the catalyst; at the same time, the inlet passage of the two-inlet-one-outlet gas selection valve and the outlet passage of the one-inlet-two-outlet gas selection valve corresponding to another reactor are replaced to produce ammonia;

[0010] S4, repeating step S3, all reactors produce ammonia gas alternately in turn, and at the same time, other reactors regenerate catalysts.

[0011] The present invention arranges more than two chemical chain reactors in parallel, switches the gas introduced into the reactor through a two-inlet and one-outlet gas selection valve, and then changes the gas atmosphere in the reactor, realizes the output of ammonia in the reactor and the in-situ regeneration of the catalyst, and achieves the reaction and regeneration cycle of the catalyst through a fixed bed reactor, avoids the catalyst regeneration separation and recovery process, avoids the flow of the catalyst in different reactors, and reduces the wear and damage to the reactor; multiple reactors alternately perform NH3 output and catalyst in-situ regeneration in turn, realize continuous flow of high-concentration NH3 output, and improve the efficiency and sustainability of synthetic ammonia; the reactor has a simple structure, is easy to operate, and has a small equipment investment, and is suitable for large-scale industrial production.

[0012] Furthermore, when the first air inlet passage introduces a mixed gas of carbon dioxide and hydrogen, the space velocity of carbon dioxide is 2-20 mL·g-1 ·min -1 , preferably 5 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 , preferably 15 mL·g -1 ·min -1 Correspondingly, the second air inlet passage is fed with a mixture of nitrogen and hydrogen, with a nitrogen space velocity of 2-20 mL·g -1 ·min -1 , preferably 5 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 , preferably 15 mL·g -1 ·min -1 At this time, the catalyst regeneration process includes catalyst nitridation, removal of the catalyst surface oxide layer (surface reduction) and removal of C-containing species on the catalyst surface; the catalyst regeneration process produces trace amounts of ammonia, water and methane, which are discharged together with the nitrogen and hydrogen that are not used by the catalyst; the catalyst produces ammonia and carbon dioxide hydrogenation products including high-concentration ammonia, as well as CO, CH4, methanol and water.

[0013] Furthermore, when only hydrogen is introduced into the first air inlet passage, the hydrogen space velocity is 5-80 mL·g -1 ·min -1 , preferably 15 mL·g -1 ·min -1 Correspondingly, only nitrogen is introduced into the second air inlet passage, and the nitrogen space velocity is 2-20mL·g -1 ·min -1 , preferably 5 mL·g -1 ·min -1 At this time, when nitrogen is introduced, the catalyst is nitrided, and when hydrogen is introduced, synthetic ammonia is produced.

[0014] Furthermore, the catalyst is one or more of metal nitride, silicon nitride, and boron nitride, including but not limited to these.

[0015] Furthermore, the metal nitride is one or more of molybdenum nitride, tungsten nitride, tantalum nitride, lanthanum nitride, cobalt-molybdenum bimetallic nitride, nickel-molybdenum bimetallic nitride and iron-molybdenum bimetallic nitride, including but not limited to these.

[0016] Furthermore, the threshold value of the ammonia concentration is selected from 1% to 10%.

[0017] Furthermore, the reaction temperature is 300-800°C, preferably 400-700°C, and more preferably 450-550°C.

[0018] Furthermore, the pressure in the reactor is 100 kPa-8000 kPa, preferably 100 kPa-5000 kPa, and more preferably 100 kPa-2000 kPa.

[0019] The second aspect of the present invention provides a product continuous output device for chemical chain cycle ammonia synthesis, which is used to implement the method described in the first aspect, comprising more than two chemical chain reactors, wherein a metal nitride catalyst is arranged in the reactor, and the gas inlet end of each reactor is respectively connected to a corresponding two-inlet-one-outlet gas selection valve, and the gas outlet end is respectively connected to a corresponding one-inlet-two-outlet gas selection valve;

[0020] The first air inlet passage of the two-inlet-one-outlet gas selection valve is used to introduce a mixed gas of carbon dioxide and hydrogen or only hydrogen, and the second air inlet passage is used to introduce a mixed gas of nitrogen and hydrogen or only nitrogen; the first air outlet passage of the one-inlet-two-outlet gas selection valve is used to discharge exhaust gas, and the second air outlet passage is used to discharge ammonia.

[0021] Furthermore, a temperature sensor is provided in the reactor to detect the temperature inside the reactor, and a pressure sensor is provided at the air inlet end of the reactor to detect the pressure of the reactor.

[0022] Furthermore, the two-inlet-one-out gas selection valve is connected to hydrogen and nitrogen gas sources, or is also connected to a carbon dioxide gas source through an inlet pipe, and a flow meter is provided on each inlet pipe for regulating the gas introduction rate.

[0023] Beneficial effects of the present invention:

[0024] The present invention arranges more than two chemical chain reactors in parallel, switches the gas introduced into the reactor through a two-inlet and one-outlet gas selection valve, and then changes the gas atmosphere in the reactor, thereby realizing the ammonia production in the reactor and the in-situ regeneration of the catalyst, and achieves the reaction and regeneration cycle of the catalyst through the fixed bed reactor, avoiding the catalyst regeneration separation and recovery process, avoiding the flow of the catalyst in different reactors, and reducing the wear and damage to the reactor.

[0025] The multiple reactors of the present invention alternately perform NH3 output and catalyst in-situ regeneration in sequence, thereby achieving continuous flow of high-concentration NH3 output and improving the efficiency and sustainability of synthetic ammonia.

[0026] The reactor of the present invention has the advantages of simple structure, convenient operation and small equipment investment, avoiding the problems of complex fluidized bed and moving bed devices and high investment, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a state-flow chart of the method for continuous output of products for chemical chain cycle ammonia synthesis of the present invention;

[0029] Figure 2 This is a state 2 flow chart of the method for continuously producing products of chemical chain cycle ammonia synthesis according to the present invention;

[0030] Explanation of the numbers in the figure: 1. Reactor, 2. Two-inlet and one-outlet gas selection valve, 3. One-inlet and two-outlet gas selection valve. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] Reference Figure 1 As shown, this embodiment provides a method for continuously producing products for chemical chain cycle ammonia synthesis, comprising the following steps:

[0034] S1. Heating two or more chemical chain reactors 1 arranged in parallel to the reaction temperature, wherein the air inlet end of each reactor 1 is respectively connected to the corresponding two-inlet and one-outlet gas selection valve 2, and the air outlet end is respectively connected to the corresponding one-inlet and two-outlet gas selection valve 3, wherein the gas selection valve in this embodiment is a solenoid valve; the first air inlet passage of the two-inlet and one-outlet gas selection valve 2 is connected to the carbon dioxide and hydrogen gas sources, and the second air inlet passage is connected to the nitrogen and hydrogen gas sources. When the two-inlet and one-outlet gas selection valve is in an open state, the second air inlet through hole is opened, and when it is closed, the first air inlet passage is opened; the first air outlet passage of the one-inlet and two-outlet gas selection valve 3 is used to discharge exhaust gas, and the second air outlet passage is used to discharge and collect ammonia and carbon dioxide hydrogenation products. When the one-inlet and two-outlet gas selection valve is in an open state, the second air outlet passage is opened, and when it is closed, the first air inlet passage is opened.

[0035] The number of reactors 1 is adjusted according to actual needs. In this embodiment, four reactors 1 are provided, and the four reactors 1 correspond to four two-inlet-one-outlet gas selection valves 2 and four one-inlet-two-outlet gas selection valves 3 , respectively.

[0036] S2, carbon dioxide and hydrogen are introduced into the corresponding reactor 1 through the first gas inlet passage of one of the two-inlet and one-outlet gas selection valves 2, referring to Figure 1 As shown, the catalyst carrying nitrogen and hydrogen species in the reactor 1 is oxidized and the surface nitrogen and hydrogen species are removed to produce ammonia and carbon dioxide hydrogenation products, which are discharged and collected through the second outlet passage of the corresponding one-inlet and two-outlet gas selection valve 3; at the same time, the second inlet passages of other two-inlet and one-outlet gas selection valves 2 respectively introduce nitrogen and hydrogen into the corresponding reactor 1, and the catalyst in the reactor 1 is supplemented with nitrogen and hydrogen species for regeneration, and the exhaust gas is discharged through the first outlet passage of the corresponding one-inlet and two-outlet gas selection valve 3.

[0037] S3. When the ammonia concentration in the gas discharged from the reactor 1 into which carbon dioxide and hydrogen are introduced is less than or equal to the threshold value, the corresponding inlet passage of the two-inlet-one-outlet gas selection valve 2 and the outlet passage of the one-inlet-two-outlet gas selection valve 3 are replaced to introduce nitrogen and hydrogen into the reactor 1 for catalyst regeneration. Figure 2 At the same time, the inlet passage of the two-inlet-one-outlet gas selection valve 2 and the outlet passage of the one-inlet-two-outlet gas selection valve 3 corresponding to another reactor 1 are replaced to introduce carbon dioxide and hydrogen into the reactor 1 to produce ammonia and carbon dioxide hydrogenation products.

[0038] The catalyst regeneration process includes catalyst nitridation, removal of the catalyst surface oxide layer (surface reduction) and removal of C-containing species on the catalyst surface. The catalyst regeneration process produces trace amounts of ammonia, water and methane, which are discharged along with the nitrogen and hydrogen that are not used by the catalyst. The catalyst produces ammonia and carbon dioxide hydrogenation products, including high-concentration ammonia, as well as CO, CH4, methanol and water.

[0039] S4, repeating step S3, all the reactors 1 are alternately introduced with carbon dioxide and hydrogen to produce ammonia and carbon dioxide hydrogenation products, and at the same time, other reactors 1 are introduced with nitrogen and hydrogen to regenerate the catalyst, and the cycle is repeated in sequence to achieve continuous production of ammonia.

[0040] In this embodiment, four chemical chain reactors 1 are arranged in parallel, and the gas introduced into the reactor 1 is switched by a two-inlet and one-outlet gas selection valve 2, thereby changing the gas atmosphere in the reactor 1, thereby realizing the output of ammonia (NH3) and carbon dioxide (CO2) hydrogenation products in the reactor 1 and the in-situ regeneration of the catalyst, thereby extending the service life of the catalyst and avoiding the catalyst regeneration, separation and recovery process; multiple reactors 1 alternately carry out the output of NH3 and CO2 hydrogenation products and the in-situ regeneration of the catalyst, thereby realizing the output of high-concentration NH3 and CO2 hydrogenation products in a continuous flow, thereby improving the efficiency and sustainability of synthetic ammonia; the reactor 1 has a simple structure, is easy to operate, and has a small equipment investment, and is suitable for large-scale industrial production.

[0041] As a preferred embodiment, when the carbon dioxide and hydrogen are introduced, the space velocity of the carbon dioxide is 2-20 mL·g -1 ·min -1 , preferably 5 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 , preferably 15 mL·g -1 ·min -1 When the nitrogen and hydrogen are introduced, the nitrogen space velocity is 2-20 mL·g -1 ·min -1 , preferably 5 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 , preferably 15 mL·g -1 ·min -1 .

[0042] As a preferred embodiment, the catalyst is one or more of metal nitride, silicon nitride, and boron nitride, and the metal nitride is one or more of molybdenum nitride, tungsten nitride, tantalum nitride, lanthanum nitride, cobalt-molybdenum bimetallic nitride, nickel-molybdenum bimetallic nitride, and iron-molybdenum bimetallic nitride.

[0043] As a preferred embodiment, the threshold value of the ammonia concentration is selected from 1% to 10%; the reaction temperature is 300-800°C, preferably 400-700°C, and more preferably 450-550°C; the pressure in the reactor 1 is 100kPa-8000kPa, preferably 100kPa-5000kPa, and more preferably 100kPa-2000kPa.

[0044] As a specific example, the process for the continuous output of the product of chemical chain cycle ammonia synthesis in this embodiment is as follows: after heating the reactor to 500°C, one of the two-inlet and one-outlet gas selection valves is controlled to introduce carbon dioxide and hydrogen, wherein the carbon dioxide flow rate is 5 mL·g -1 ·min -1 , hydrogen space velocity is 15 mL·g -1 ·min -1 The mixed gas was passed through a cobalt-molybdenum bimetallic nitride catalyst and reacted at 500°C and normal pressure to carry out the CO2-induced NH3 desorption process, producing ammonia and carbon dioxide hydrogenation products. After 5 minutes, the ammonia concentration was reduced to 1%. The two-inlet-one-out gas selection valve corresponding to the reactor was controlled to introduce nitrogen and hydrogen, wherein the nitrogen space velocity was 5 mL·g -1 ·min -1 , hydrogen space velocity is 15 mL·g -1 ·min -1 The mixed gas passes through the catalyst and reacts at 500℃ and normal pressure. The catalyst is supplemented with nitrogen and hydrogen species for regeneration. After 15 minutes, the gas selection valve is controlled to introduce carbon dioxide and hydrogen. During the process, one reactor performs the CO2-induced NH3 desorption process, and the other three reactors perform the catalyst regeneration process, and this cycle repeats.

[0045] Example 2

[0046] This embodiment provides a method for continuously producing products for chemical chain cycle ammonia synthesis. The difference from Embodiment 1 is that the number of reactors 1 is set to six, the first air inlet passage of the two-inlet-one-outlet solenoid valve 2 is used to introduce hydrogen, and the second air inlet passage is used to introduce nitrogen, the first air outlet passage of the one-inlet-two-outlet solenoid valve 3 is used to discharge exhaust gas, and the second air outlet passage is used to collect ammonia products, and the catalyst is nickel-molybdenum bimetallic nitride (NiMoN).

[0047] As a specific example, the process for the continuous production of the product of chemical chain cycle ammonia synthesis in this embodiment is as follows: after heating the reactor to 500°C, one of the two-inlet-one-out gas selection valves is controlled to introduce hydrogen, wherein the hydrogen space velocity is 15 mL·g -1 ·min -1 The gas passes through the catalyst and reacts at 500℃ and normal pressure to produce ammonia through NH3 desorption process. After 5 minutes, the ammonia concentration is reduced to 1%. The two-inlet and one-outlet gas selection valve corresponding to the reactor is controlled to introduce nitrogen, where the nitrogen space velocity is 5mL·g -1 ·min -1The gas passes through the catalyst and reacts at 500℃ and normal pressure. The catalyst is supplemented with nitrogen species for regeneration. After 25 minutes, the gas selection valve is controlled to introduce carbon dioxide and hydrogen. During the process, one reactor performs NH3 desorption process, and the other five reactors perform catalyst regeneration process, and this cycle is repeated.

[0048] Example 3

[0049] This embodiment provides a product continuous output device for chemical chain cycle synthesis of ammonia, referring to Figure 1 , used to implement the method described in Example 1, including more than two chemical chain reactors 1. This embodiment is provided with four reactors 1, 100 mg of cobalt-molybdenum bimetallic nitride catalyst is placed in the reactor 1, the inlet end of each reactor 1 is respectively connected to the corresponding two-inlet-one-outlet gas selection valve 2, and the outlet end is respectively connected to the corresponding one-inlet-two-outlet gas selection valve 3; the first inlet passage of the two-inlet-one-outlet gas selection valve 2 is used to introduce carbon dioxide and hydrogen, and the second inlet passage is used to introduce nitrogen and hydrogen; the first outlet passage of the one-inlet-two-outlet gas selection valve 3 is used to discharge exhaust gas, and the second outlet passage is used to discharge ammonia and carbon dioxide hydrogenation products.

[0050] As a preferred embodiment, a temperature sensor is provided in the reactor 1 to detect the temperature in the reactor 1, and a pressure sensor is provided at the gas inlet end of the reactor 1 to detect the pressure of the reactor 1. The two-inlet-one-out gas selection valve 2 is connected to the carbon dioxide, hydrogen and nitrogen gas sources through the gas inlet pipe, and a flow meter is provided on each gas inlet pipe to adjust the gas introduction rate.

[0051] In summary, the present invention arranges more than two chemical chain reactors in parallel, switches the gas introduced into the reactor through a two-inlet and one-outlet gas selection valve, and then changes the gas atmosphere in the reactor, realizes the ammonia output in the reactor and the in-situ regeneration of the catalyst, and achieves the reaction and regeneration cycle of the catalyst through a fixed bed reactor, avoids the catalyst regeneration separation and recovery process, avoids the flow of the catalyst in different reactors, and reduces the wear and damage to the reactor; multiple reactors alternately perform NH3 output and catalyst in-situ regeneration in turn, realize continuous flow of high-concentration NH3 output, and improve the efficiency and sustainability of synthetic ammonia; the reactor has a simple structure, is easy to operate, and has a small equipment investment, avoiding the problems of complex fluidized bed and moving bed devices and high investment, and is suitable for large-scale industrial production.

[0052] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for continuously producing products for chemical chain cycle ammonia synthesis, characterized in that: The steps include: S1. Heating two or more chemical chain reactors arranged in parallel to a reaction temperature, wherein the gas inlet end of each reactor is respectively connected to a corresponding two-inlet-one-outlet gas selection valve, and the gas outlet end is respectively connected to a corresponding one-inlet-two-outlet gas selection valve; S2, a mixed gas of carbon dioxide and hydrogen or only hydrogen is introduced into the corresponding reactor through the first gas inlet passage of one of the two-inlet-one-outlet gas selection valves, and the catalyst carrying nitrogen species in the reactor removes the surface nitrogen species to produce ammonia, which is discharged and collected through the second gas outlet passage of the corresponding one-inlet-two-outlet gas selection valve; at the same time, a mixed gas of nitrogen and hydrogen or only nitrogen is introduced into the corresponding reactor through the second gas inlet passages of the other two-inlet-one-outlet gas selection valves, and the catalyst in the reactor is regenerated, and the waste gas is discharged through the first gas outlet passage of the corresponding one-inlet-two-outlet gas selection valve; S3. When the ammonia concentration in the gas discharged from the reactor producing ammonia is less than or equal to the threshold value, the corresponding inlet passage of the two-inlet-one-outlet gas selection valve and the outlet passage of the one-inlet-two-outlet gas selection valve are replaced to regenerate the catalyst; at the same time, the inlet passage of the two-inlet-one-outlet gas selection valve and the outlet passage of the one-inlet-two-outlet gas selection valve corresponding to another reactor are replaced to produce ammonia; S4, repeating step S3, all reactors produce ammonia gas alternately in turn, and at the same time, other reactors regenerate catalysts.

2. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 1, characterized in that: When the first air inlet passage is fed with a mixture of carbon dioxide and hydrogen, the space velocity of carbon dioxide is 2-20 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 Correspondingly, the second air inlet passage is fed with a mixture of nitrogen and hydrogen, with a nitrogen space velocity of 2-20 mL·g -1 ·min -1 , hydrogen space velocity is 5-80mL·g -1 ·min -1 .

3. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 1, characterized in that: When only hydrogen is introduced into the first air inlet passage, the hydrogen space velocity is 5-80 mL·g -1 ·min -1 Correspondingly, only nitrogen is introduced into the second air inlet passage, and the nitrogen space velocity is 2-20mL·g -1 ·min -1 .

4. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 1, characterized in that: The catalyst is one or more of metal nitride, silicon nitride and boron nitride.

5. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 4, characterized in that: The metal nitride is one or more of molybdenum nitride, tungsten nitride, tantalum nitride, lanthanum nitride, cobalt-molybdenum bimetallic nitride, nickel-molybdenum bimetallic nitride and iron-molybdenum bimetallic nitride.

6. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 1, characterized in that: The threshold value of the ammonia concentration is selected from 1% to 10%.

7. The method for continuous production of products for chemical chain cycle ammonia synthesis according to claim 1, characterized in that: The reaction temperature is 300-800°C.

8. A product continuous output device for chemical chain cycle ammonia synthesis, used for implementing the method according to any one of claims 1 to 7, characterized in that: It comprises two or more chemical chain reactors, wherein a metal nitride catalyst is arranged in the reactor, and the gas inlet end of each reactor is respectively connected to a corresponding two-inlet-one-outlet gas selection valve, and the gas outlet end is respectively connected to a corresponding one-inlet-two-outlet gas selection valve; The first air inlet passage of the two-inlet-one-outlet gas selection valve is used to introduce a mixed gas of carbon dioxide and hydrogen or only hydrogen, and the second air inlet passage is used to introduce a mixed gas of nitrogen and hydrogen or only nitrogen; the first air outlet passage of the one-inlet-two-outlet gas selection valve is used to discharge exhaust gas, and the second air outlet passage is used to discharge ammonia.

9. The product continuous output device for chemical chain cycle ammonia synthesis according to claim 8, characterized in that: A temperature sensor is arranged in the reactor, and a pressure sensor is arranged at the air inlet end of the reactor.

10. The product continuous output device for chemical chain cycle ammonia synthesis according to claim 8, characterized in that: The two-inlet-one-outlet gas selection valve is connected to hydrogen and nitrogen gas sources, or is also connected to a carbon dioxide gas source through an inlet pipe, and a flow meter is arranged on each inlet pipe.

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