Chemical looping hydrogen production system and method

Abstract

The application discloses a chemical cycle hydrogen production system, comprising: a first partition unit arranged between an air reactor and a combustion reactor; an upper portion of the first partition unit is provided with a cyclone separator for receiving oxidized oxygen carriers from the air reactor and performing gas-solid separation; a bottom portion of the first partition unit is provided with a nitrogen stripping section, forming a gas partition combined with gas-solid separation and nitrogen stripping; a second partition unit arranged between the combustion reactor and a steam reactor and communicated with a first riser section extending downward from a bottom portion of the combustion reactor; a bottom portion of the second partition unit is provided with a nitrogen stripping section, forming a gas partition combined with dense phase material sealing in the first riser section and nitrogen stripping; a third partition unit arranged between the steam reactor and the air reactor and communicated with a second riser section extending downward from a bottom portion of the steam reactor; a bottom portion of the third partition unit is provided with a nitrogen stripping section, forming a gas partition combined with dense phase material sealing in the second riser section and nitrogen stripping. The application also discloses a chemical cycle hydrogen production method.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, and in particular to a chemical ring hydrogen production system and method. Background Technology

[0002] With the ever-increasing demand for energy, the consumption of fossil fuels and total CO2 emissions are rising rapidly, making a "clean, low-carbon, safe, and efficient" energy transformation an inevitable trend. While renewable energy sources (such as solar, wind, and hydropower) are being used on a large scale as alternative energy sources, their inherent intermittency, volatility, and randomness are limiting. Hydrogen, on the other hand, is a clean secondary energy carrier with a high calorific value and produces only water as a byproduct, causing no environmental pollution. Therefore, hydrogen energy, as a clean and efficient ideal fuel, is considered by the energy sector as the "fuel of the future" and has excellent application prospects.

[0003] Currently, hydrogen production mainly relies on fossil fuels, and consumption is primarily as an industrial raw material. The scale of clean energy hydrogen production and the energy utilization of hydrogen is relatively small. In China, nearly 70% of hydrogen is produced from fossil fuels such as coal, natural gas, and oil; about 30% is produced from industrial by-product gases; and less than 1% is produced through water electrolysis.

[0004] The hydrogen energy industry chain typically consists of three parts: hydrogen production, storage and transportation, and application, with hydrogen production being the first link in the chain. Currently, 96% of the world's commercial hydrogen is produced from fossil fuels such as coal, oil, and natural gas. As the world's largest hydrogen producer, China's proportion of fossil fuels in its hydrogen production feedstock is even higher. At present, China's mainstream hydrogen production technologies include coal-to-hydrogen, natural gas-to-hydrogen, oil-to-hydrogen, and renewable energy-to-hydrogen. Among these, coal-to-hydrogen technologies include coking and gasification of coal, with the latter being the mainstream process. However, hydrogen production technologies using fossil fuels as feedstocks are accompanied by significant emissions of greenhouse gases such as CO2, necessitating the implementation of corresponding carbon capture technologies. Therefore, to meet the ever-increasing demand for hydrogen energy, developing more environmentally friendly and economical hydrogen production technologies is imperative.

[0005] Chemical cyclic hydrogen production is a novel low-carbon hydrogen production technology. Its core principle is a partitioned reaction integration process based on lattice oxygen transfer. Combustion, steam, and air reactions all take place in different reactors, primarily in moving bed or fluidized bed reactor configurations. A key aspect of this technology is achieving gas isolation between different reactors to prevent cross-contamination, which is crucial for product purity and operational safety.

[0006] CN215364900U discloses a chemical ring hydrogen production process system, including a fuel reactor, a steam reactor, and an air reactor. An interstage combustion reactor is installed between the fuel reactor and the steam reactor, and between the fuel reactor and the air reactor, which solves the problem of fuel gas leakage from the fuel reactor and recovers the heat generated during the combustion reaction of the leaked gas to power the device, improving the utilization rate of the fuel gas. Multiple heat exchangers and steam generators are also used to recover the heat of the high-temperature gases generated by each reactor, used to preheat the fuel gas and steam, and simultaneously condense water vapor to obtain pure hydrogen and capture pure carbon dioxide. However, each interstage burner in this system requires a cyclone separator for gas-solid separation, which increases the construction cost of the device. Especially between the fuel reactor and the steam reactor, due to the limited amount of gas entrained in the outlet solids, the operation of the cyclone separator in this section is difficult and can negatively impact the stable operation of the entire device. Furthermore, this method of "gas isolation" is not ideal.

[0007] Therefore, there is an urgent need for a chemical ring hydrogen production system and method that can not only effectively isolate gases between different reactors to prevent cross-gas leakage, but also ensure the stable operation of the entire system and effectively reduce the system's construction costs.

[0008] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to provide a chemical ring hydrogen production system and method, which uses a fluidized bed reactor and an oxygen carrier in a dense phase at the bottom of the reactor for primary gas isolation, and nitrogen stripping for secondary gas isolation between reactors, so that more effective gas isolation can be achieved between different reactors.

[0010] Another objective of this invention is to provide a chemical ring hydrogen production system and method, which can effectively prevent nitrogen used in secondary isolation from entering the upper and lower reactors through interlocked control of gas pressure and material level in the reactor.

[0011] To achieve the above objectives, according to a first aspect of the present invention, a chemically cyclic hydrogen production system is provided. This system is a cyclic system in which an oxygen carrier participates in the reaction sequentially and independently in a combustion reactor, a steam reactor, and an air reactor. It further includes at least: a first isolation unit disposed between the air reactor and the combustion reactor and used as a silo; a cyclone separator is provided in the upper part of the first isolation unit for receiving the oxidized oxygen carrier from the air reactor and performing gas-solid separation; a nitrogen gas lift section is provided at the bottom of the first isolation unit, forming a gas-solid separation and nitrogen gas lift section. The system includes a gas isolation unit; a second isolation unit, which is located between the combustion reactor and the steam reactor and communicates with the first vertical pipe section extending downward from the bottom of the combustion reactor. The bottom of the second isolation unit is provided with a nitrogen gas stripping section, forming a gas isolation combination of dense phase material sealing and nitrogen gas stripping within the first vertical pipe section; and a third isolation unit, which is located between the steam reactor and the air reactor and communicates with the second vertical pipe section extending downward from the bottom of the steam reactor. The bottom of the third isolation unit is provided with a nitrogen gas stripping section, forming a gas isolation combination of dense phase material sealing and nitrogen gas stripping within the second vertical pipe section.

[0012] Furthermore, in the above technical solution, the nitrogen gas lift section in the first partition unit, the second partition unit, and the third partition unit may be provided with a Johnson mesh with a V-shaped cross section to disperse the nitrogen flow and increase the gas-solid contact area.

[0013] Furthermore, in the above technical solution, the first partition unit, the second partition unit, and the third partition unit can all be equipped with interlocking control mechanisms. The interlocking control adopts a pressure difference interlocking control method to maintain a certain material level in the partition unit, so that the pressure in the corresponding partition unit is slightly lower than that in the previous stage reactor and slightly higher than that in the next stage reactor, ensuring the circulation of oxygen carrier while preventing nitrogen from entering the previous stage and / or the next stage reactor.

[0014] Furthermore, in the above technical solutions, both the combustion reactor and the steam reactor can be downflow fluidized bed reactors and preferably adopt the same structure, both including a settling section, a bed section and a riser section.

[0015] Furthermore, in the above technical solution, the settling section may be equipped with a first pressure measuring point to assess the overall pressure change of the system; the bed section may be equipped with a second pressure measuring point, which is multiple and evenly spaced along the height direction of the bed to assess the change in the material surface height.

[0016] Furthermore, in the above technical solution, the fluidizing air inlet of the downflow fluidized bed reactor can be located between the bed section and the riser section, and a gas phase distribution plate can be installed at the fluidizing air inlet to convert radial fluidizing air with a certain flow rate into axial fluidizing air that is uniformly sprayed upward.

[0017] Furthermore, in the above technical solution, a gas filter may be provided above the settling section to filter the gaseous products containing high-purity CO2 from the combustion reactor and to filter the gaseous products containing high-purity H2 from the steam reactor.

[0018] Furthermore, in the above technical solution, the air reactor can be an upward-flowing riser reactor, preferably comprising a lower section, a middle expansion section, and an upper section.

[0019] Furthermore, in the above technical solution, the oxygen carrier inlet of the air reactor can be set in the lower section and arranged at an angle. The air introduced at the bottom of the lower section is used as fluidizing air to transport the oxygen carrier upward while carrying out the oxidation reaction. When the oxygen carrier reaches the middle expansion section, the flow rate decreases and the reaction time can be extended.

[0020] According to a second aspect of the present invention, the present invention provides a chemically cyclic hydrogen production method, using the aforementioned system, comprising at least the following steps: A. An oxygen carrier, after being treated by cyclone separation and nitrogen stripping in the first isolation unit, enters the combustion reactor from the side of the settling section; the feed gas, as the bed fluidizing air, enters the bed section from the bottom, fluidizing the oxygen carrier in the combustion reactor and carrying out the combustion reaction to obtain high-purity CO2; B. An oxygen carrier, after being treated by dense phase conveying in the bottom riser section of the combustion reactor and nitrogen stripping in the second isolation unit, enters the steam reactor from the side of the settling section; water vapor, as the bed fluidizing air, enters the bed section from the bottom, fluidizing the oxygen carrier in the steam reactor and carrying out the reaction to obtain high-purity H2; C. An oxygen carrier, after being treated by dense phase conveying in the bottom riser section of the steam reactor and nitrogen stripping in the third isolation unit, enters from the lower section of the air reactor; air is introduced at the lower feed point as fluidizing air, conveying the oxygen carrier upward while carrying out the oxidation reaction, extending the reaction time in the middle expansion section, and conveying the oxygen carrier to the cyclone separator of the first isolation unit in the upper section. This completes the system loop.

[0021] Furthermore, in the above technical solution, the raw material gas in step A is a low-carbon alkane, which can be one or more of methane, ethane, propane, and butane.

[0022] Furthermore, in the above technical solution, the active component of the oxygen carrier can be one or more of Fe, Ni, Ce, Mn, and Cu; the additive can be one or more of transition metals and rare earth metals; the oxygen carrier is formed into microspheres for fluidized beds, with an average particle size preferably of 40–90 μm.

[0023] Furthermore, in the above technical solution, the operating conditions of the combustion reactor are as follows: the reaction pressure is preferably 0.1 to 1 MPa; the reaction temperature is preferably 700 to 1000 °C; and the gas flow rate is preferably 0.05 to 0.2 m / s.

[0024] Furthermore, in the above technical solution, the operating conditions of the steam reactor are as follows: the reaction pressure is preferably 0.1 to 1 MPa; the reaction temperature is preferably 400 to 800 °C; and the gas flow rate is preferably 0.1 to 0.3 m / s.

[0025] Furthermore, in the above technical solution, the operating conditions of the air reactor are as follows: the reaction pressure is preferably 0.1 to 1 MPa; the reaction temperature is preferably 700 to 1000 °C; and the gas flow rate is preferably 1 to 15 m / s.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The system and method of this invention adopts a chemical cyclic hydrogen production technology route using hydrocarbons as raw materials. At the same time, an effective gas isolation method is used between different reactors to directionally control the gas flow, prevent impurity gases from affecting the purity of hydrogen, and achieve the preparation of high-purity hydrogen.

[0028] 2) In this invention, the oxygen carrier at the outlet of the air reactor enters the first isolation unit, where gas isolation is achieved through a combination of "gas-solid separation + nitrogen stripping". In the combustion reactor, after reaction in the bed section, the oxygen carrier is transported to the second isolation unit via a dense-phase riser section. The oxygen carrier after nitrogen stripping enters the steam reactor. During this process, gas isolation is achieved through a combination of "dense-phase material sealing + nitrogen stripping". In the steam reactor, after reaction in the bed section, the oxygen carrier is transported to the third isolation unit via a dense-phase riser section. The oxygen carrier after stripping enters the air reactor. Similarly, gas isolation is achieved through a combination of "dense-phase material sealing + nitrogen stripping". This invention, through the arrangement of three gas isolation units between the three reactors and the coordination of dense-phase transport in the riser sections at the bottom of the combustion and steam reactors, effectively prevents "cross-contamination" of reactant gases and / or nitrogen between the reactors, ensuring not only the purity of the product gases but also the safety of the entire system operation.

[0029] 3) This invention employs a "V"-shaped structure composed of Johnson nets at the bottom of the nitrogen stripping section. Nitrogen gas can enter the nitrogen stripping section from the bottom and undergo countercurrent contact with the solid oxygen carrier for stripping. The Johnson nets serve two purposes: firstly, they act as a gas-solid separator, allowing nitrogen gas to pass through the "V"-shaped Johnson nets while preventing the oxygen carrier from flowing out; secondly, the "V"-shaped Johnson nets also disperse the nitrogen flow, increasing the gas-solid contact area and thus improving the nitrogen stripping effect.

[0030] 4) This invention maintains a certain material level by using the synergistic effect of the gas isolation unit and the solid circulation interlock control. In this way, the normal operation of the system circulation can be effectively guaranteed, and nitrogen can be further prevented from "crossing over" between the upper and lower reactors.

[0031] 5) The settling sections of both the combustion reactor and the steam reactor of this invention are equipped with a first pressure measuring point, which can be used to assess the overall pressure change of the system; the bed sections of both reactors are equipped with multiple second pressure measuring points evenly spaced along the bed height direction, which can be used to assess the change in material level. The pressure data measured in real time by the first and second pressure measuring points can provide data basis for the "interlock control" of this invention;

[0032] 6) Through the system and method of the present invention, complete combustion of low-carbon alkanes can be achieved in the combustion reactor, and high-purity CO2 can be obtained by condensation, which can significantly reduce carbon capture costs; at the same time, high-purity hydrogen can be directly obtained in the steam reactor, effectively reducing the production cost of high-purity hydrogen.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the connection of the chemical ring hydrogen production system of the present invention.

[0035] Figure 2 This is a schematic diagram of the internal structure of the first partition unit in the system of the present invention.

[0036] Figure 3 This is a schematic diagram of the internal structure of the second partition unit in the system of the present invention.

[0037] Figure 4 This is a schematic diagram of the internal structure of the third partition unit in the system of the present invention.

[0038] Figure 5 This is a schematic diagram of the combustion reactor and steam reactor in the system of this invention.

[0039] Figure 6 This is a schematic diagram of the air reactor in the system of the present invention.

[0040] Explanation of key figure labels:

[0041] 1-First partition unit, 10-Cyclone separator, 11-First Johnson mesh, 12-First interlocking mechanism, 2-Combustion reactor, 21-Settling section of combustion reactor, 22-Bed section of combustion reactor, 23-Riser section of combustion reactor, 24-First pressure measuring point of combustion reactor, 25-Second pressure measuring point of combustion reactor, 26-Low-carbon alkane distribution plate, 27-Gas filter, 3-Second partition unit, 31-Second Johnson mesh, 32-Second interlocking mechanism, 4-Steam reactor, 41-Settling section of steam reactor, 42-Bed section of steam reactor, 43-Riser section of steam reactor, 44-First pressure measuring point of steam reactor, 45-Second pressure measuring point of steam reactor, 46-Steam distribution plate, 27-Gas filter, 5-Third partition unit, 51-Third Johnson mesh, 52-Third interlocking mechanism, 6-Air reactor. Detailed Implementation

[0042] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0043] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0044] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0045] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0046] refer to Figure 1The system and method of this invention employ a chemical cyclic hydrogen production technology route using hydrocarbons as raw materials. Simultaneously, by using effective gas isolation between different reactors, the gas flow can be directionally controlled to prevent impurities from affecting hydrogen purity, thus achieving the production of high-purity hydrogen. The reactors involved in this invention include a combustion reactor 2, a steam reactor 4, and an air reactor 6.

[0047] The reaction occurring in combustion reactor 2 involves the complete oxidation of the lattice oxygen of hydrocarbons to produce CO2 and H2O. Taking methane as an example, it reacts with the oxidized oxygen carrier (M... x O y The reaction equation is:

[0048] CH4+M x O y →CO2 + 2H2O + M x O y-4

[0049] The reaction occurring in steam reactor 4 involves water vapor contacting a reduced metal at high temperature, resulting in a cracking reaction that produces hydrogen gas. The water vapor then reacts with the reduced oxygen carrier (M... x O y-4 The reaction equation is:

[0050] 2H2O+M x O y-4 →2H2+M x O y-2

[0051] The reaction occurring in air reactor 6 is a partial oxidation of the oxygen carrier (M). x O y-2 The complete oxidation reaction between the oxygen and air at high temperatures produces an oxidized oxygen carrier (M). x O y The reaction equation is:

[0052] M x O y-2 +O2→M x O y

[0053] The three reactors above form a reaction cycle for the continuous production of high-purity hydrogen.

[0054] like Figures 1 to 4 As shown, the present invention provides a chemically cyclic hydrogen production system, which is a cyclic system in which an oxygen carrier participates in the reaction sequentially and independently in a combustion reactor 2, a steam reactor 4 and an air reactor 6. In addition to the above-mentioned reactors, it also includes at least a first isolation unit 1, a second isolation unit 3 and a third isolation unit 5.

[0055] Further as Figure 1 ,2 As shown, the first partition unit 1 is located between the air reactor 6 and the combustion reactor 2 and can also be used as a silo. A cyclone separator 10 is installed at the upper part of the first partition unit 1 to receive the oxidized oxygen carrier from the air reactor 6 and perform gas-solid separation. A nitrogen stripping section (i.e., the area below the material surface) is located at the bottom of the first partition unit 1, forming a gas partition combining gas-solid separation and nitrogen stripping. The oxidized oxygen carrier from the top outlet of the air reactor 6 enters the cyclone separator 10 for gas-solid separation, which separates the oxygen-deficient air in the material and discharges it separately from the first partition unit 1, preventing the oxygen-deficient air from flowing downwards into the combustion reactor 2, thus forming a primary gas partition. The separated oxygen carrier flows downwards along the material leg of the cyclone separator 10 into the nitrogen stripping section. By introducing nitrogen gas into the bottom of the first partition unit 1 (nitrogen gas can be introduced from the bottom side), a secondary gas partition is formed using nitrogen stripping. Specifically, nitrogen flows counter-currently to the top within the gas-lift section and is discharged from the exhaust port at the top of the first partition unit 1 under the control of a pressure control valve. This nitrogen exhaust port design effectively prevents nitrogen from crossing between the upper and lower reactors (i.e., the air reactor and the combustion reactor). The oxygen carrier, after gas-lifting within the first partition unit 1, enters the combustion reactor 2 from the bottom downwards.

[0056] Further as Figure 1 , 3 As shown, the second partition unit 3 is located between the combustion reactor 2 and the steam reactor 4 and is connected to the first riser section extending downward from the bottom of the combustion reactor 2 (i.e., combustion reactor riser section 23, see reference). Figure 5 The second partition unit 3 has a nitrogen stripping section at its bottom (i.e., the area below the material surface), forming a gas isolation combining the dense phase material seal and nitrogen stripping within the combustion reactor riser section 23. Specifically, after the oxygen carrier exits the combustion reactor 2, it first moves downward through the dense phase combustion reactor riser section 23, where the dense phase isolates most of the reaction gases. From the combustion reactor riser section 23, it enters the stripping section of the second partition unit 3, where nitrogen is used for stripping. The nitrogen flows counter-currently to the top within the stripping section and is discharged from the exhaust port at the top of the second partition unit 3 under the control of a pressure control valve. The nitrogen exhaust port designed in this location effectively prevents nitrogen from crossing between the upper and lower reactors (i.e., the combustion reactor and the steam reactor). After being stripped within the second partition unit 3, the oxygen carrier enters the steam reactor 4 from the bottom downwards.

[0057] The third partition unit 5 is located between the steam reactor 4 and the air reactor 6 and is connected to the second riser section (i.e., steam reactor riser section 43, see reference) extending downward from the bottom of the steam reactor 4. Figure 5The third partition unit 5 has a nitrogen stripping section at its bottom (i.e., the area below the material surface), forming a gas isolation combining the dense phase material seal and nitrogen stripping within the steam reactor riser section 43. Specifically, after the oxygen carrier exits the steam reactor 4, it first moves downward through the dense phase of the steam reactor riser section 43, where the dense phase isolates most of the reaction gases. From the steam reactor riser section 43, it enters the stripping section of the third partition unit 5, where nitrogen is used for stripping. The nitrogen flows counter-currently to the top within the stripping section and is discharged from the exhaust port at the top of the third partition unit 5 under the control of a pressure control valve. The nitrogen exhaust port designed in this location effectively prevents nitrogen from crossing between the upper and lower reactors (i.e., the steam reactor and the air reactor). After being stripped within the third partition unit 5, the oxygen carrier enters the air reactor 6 from the bottom downwards.

[0058] The present invention employs the above-mentioned technical solution, in which the oxygen carrier can continuously circulate between the various reactors. The specific circulation process is as follows: the oxygen carrier from the air reactor 6 enters the first isolation unit 1, where it undergoes gas isolation via a combination of "gas-solid separation + nitrogen stripping" before flowing downwards into the combustion reactor 2; after reaction in the bed section, the oxygen carrier in the combustion reactor 2 is conveyed to the second isolation unit 3 via a riser section, and the nitrogen-stripped oxygen carrier enters the steam reactor 4, where a combination of "dense phase material sealing + nitrogen stripping" is used for gas isolation; after reaction in the bed section, the oxygen carrier in the steam reactor 4 is conveyed to the third isolation unit 5 via a riser section, and the stripped oxygen carrier enters the air reactor 6, where the same combination of "dense phase material sealing + nitrogen stripping" is used for gas isolation; the air reactor 6 introduces air as fluidizing air to rapidly transport the oxygen carrier upwards to the top first isolation unit 1. During the circulation and reaction of the oxygen carrier within the system as described above, the combination of the three gas isolation units between the three reactors and the dense phase transport of the bottom riser sections of the combustion reactor 2 and the steam reactor 4 effectively prevents the "cross-contamination" of reaction gases and / or nitrogen between the reactors. This not only ensures the purity of the product gases but also guarantees the safety of the entire system operation.

[0059] Further as Figures 2 to 4 As shown, preferably but not limitingly, the nitrogen stripping sections in the first partition unit 1, the second partition unit 3, and the third partition unit 5 are each provided with a Johnson mesh with a V-shaped cross-section (i.e., Figure 2 The first Johnson website in the middle 11, Figure 3 The second Johnson website 31, Figure 4The third Johnson net (51) is used to disperse nitrogen flow and increase the gas-solid contact area. Specifically, a "V"-shaped structure composed of Johnson nets is used at the bottom of the nitrogen stripping section. Nitrogen can enter the nitrogen stripping section from the bottom and make countercurrent contact with the solid oxygen carrier for stripping. The Johnson net can, on the one hand, isolate the gas and solid, that is, nitrogen can pass through the "V"-shaped Johnson net, while the oxygen carrier will not flow out through the Johnson net; on the other hand, the "V"-shaped Johnson net can also disperse the nitrogen flow, thereby increasing the gas-solid contact area and improving the nitrogen stripping effect.

[0060] Further as Figures 2 to 4 As shown, preferably but not limitingly, the first isolation unit 1, the second isolation unit 3, and the third isolation unit 5 can all be equipped with interlocking control mechanisms. The interlocking control adopts a pressure differential interlocking control method, which can maintain a certain material level within the isolation unit, ensuring that the pressure in the corresponding isolation unit is slightly lower than the previous reactor and slightly higher than the next reactor. This guarantees the circulation of the oxygen carrier while preventing nitrogen from entering the previous and / or next reactor. Therefore, this invention, through the synergistic effect of the gas isolation unit and the solid circulation interlocking control, can maintain a certain material level. In this way, the normal operation of the system circulation can be effectively guaranteed, and nitrogen can be further prevented from "cross-contaminating" between the upper and lower reactors.

[0061] Further as Figure 5 As shown, both the combustion reactor 2 and the steam reactor 4 of the present invention are preferably downflow fluidized bed reactors, and both can adopt the same structure, including a settling section, a bed section, and a riser section. That is, the feed is respectively fed into the settling section 21 of the combustion reactor 2 and the settling section 41 of the steam reactor 4, the reaction occurs in the bed section 22 of the combustion reactor 2 and the bed section 42 of the steam reactor 4, and dense phase transport is carried out in the riser section 23 of the combustion reactor 2 and the riser section 43 of the steam reactor 4. Further as... Figure 5 As shown, both reactors have a first pressure measuring point 24 / 44 in the settling section, which can be used to assess the overall pressure change of the system; both reactors have a second pressure measuring point 25 / 45 in the bed section, which is preferably multiple and evenly spaced along the bed height direction, and can be used to assess the change in material level. The fluidizing air inlets of both reactors are located between the bed section and the riser section. The fluidizing air for combustion reactor 2 is a low-carbon alkane gas (e.g., methane), and the fluidizing air for steam reactor 4 is water vapor. A gas phase distribution plate (i.e.,...) is installed at the fluidizing air inlet. Figure 5 The low-carbon alkane distribution disk 26 and the water vapor distribution disk 46 are used to convert radial fluidizing air at a certain velocity into uniformly upward-sprayed axial fluidizing air. Further, as... Figure 5As shown, a gas filter 27 / 47 is provided above the settling section 21 / 41. The gas filter 27 can be used to filter the gaseous product containing high-purity CO2 from the combustion reactor 2, and the gas filter 47 can be used to filter the gaseous product containing high-purity H2 from the steam reactor 4.

[0062] Further as Figure 6 As shown, the air reactor 6 of the present invention is an upward-flowing riser reactor, preferably comprising a lower section 61, a middle expansion section 62, and an upper section 63. The oxygen carrier inlet of the air reactor 6 is located in the lower section 61 and is arranged at an angle. Air introduced from the bottom of the lower section 61 serves as fluidizing air, conveying the oxygen carrier upward while simultaneously carrying out the oxidation reaction. When the oxygen carrier reaches the middle expansion section 62, the flow rate decreases, effectively extending the reaction time.

[0063] refer to Figures 1 to 6 As shown, this invention also provides a chemical cyclic hydrogen production method, which utilizes the aforementioned system for oxygen carrier recycling. The active component of the oxygen carrier used in this invention is preferably one or more of Fe, Ni, Ce, Mn, and Cu; the auxiliary agent is preferably one or more of transition metals and rare earth metals; the oxygen carrier is formed into microspheres specifically for fluidized beds, with an average particle size preferably of 40–90 μm. The method of this invention includes the following steps:

[0064] In step S101, the oxygen carrier, after cyclone separation and nitrogen stripping treatment in the first isolation unit 1, enters the combustion reactor 2 from the side of the settling section 21. The raw material gas (i.e., low-carbon alkanes, which are one or more of methane, ethane, propane, and butane) enters the bed section 22 from the bottom as bed fluidizing air, fluidizing the oxygen carrier in the combustion reactor 2 and initiating a combustion reaction to obtain high-purity CO2. Using the above system of the present invention, the product after combustion reaction, after condensation and dehydration, yields CO2 with high purity. The operating conditions of the combustion reactor 2 are: preferably, the reaction pressure is 0.1–1 MPa; preferably, the reaction temperature is 700–1000 °C; and preferably, the gas flow rate is 0.05–0.2 m / s.

[0065] In step S102, the oxygen carrier, after being transported by the dense phase through the bottom riser section 23 of the combustion reactor 2 and treated by nitrogen stripping through the second isolation unit 3, enters the steam reactor 4 from the side of the settling section 41; water vapor, as the bed fluidizing air, enters the bed section 42 from the bottom, fluidizing the oxygen carrier in the steam reactor 4 and reacting it to obtain high-purity H2. The operating conditions of the steam reactor 4 are as follows: the reaction pressure is preferably 0.1–1 MPa; the reaction temperature is preferably 400–800 °C; and the gas flow rate is preferably 0.1–0.3 m / s.

[0066] In step S103, the oxygen carrier, after being conveyed by the dense phase in the bottom riser section 43 of the steam reactor 4 and treated by nitrogen stripping in the third isolation unit 5, enters from the lower section 61 of the air reactor 6. Air is introduced at the lower feed point as fluidizing air to transport the oxygen carrier upward while simultaneously carrying out the oxidation reaction. The reaction time is extended in the middle expansion section 62, and the oxygen carrier is then transported to the cyclone separator 10 of the first isolation unit 1 in the upper section 63. The operating conditions of the air reactor 6 are as follows: the reaction pressure is preferably 0.1–1 MPa; the reaction temperature is preferably 700–1000 °C; and the gas flow rate is preferably 1–15 m / s.

[0067] This completes the system loop of the present invention. After step S103 is executed, the process proceeds to step S101.

[0068] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A chemically cyclic hydrogen production system, characterized in that, The system is a circulating system in which the oxygen carrier participates in the reaction sequentially and independently in the combustion reactor, steam reactor, and air reactor, including: The first partition unit is located between the air reactor and the combustion reactor and is used as a silo. The upper part of the first partition unit is provided with a cyclone separator for receiving the oxidized oxygen carrier from the air reactor and performing gas-solid separation. The bottom of the first partition unit is provided with a nitrogen stripping section, forming a gas partition that combines gas-solid separation and nitrogen stripping. The second partition unit is located between the combustion reactor and the steam reactor and is connected to the first riser section extending downward from the bottom of the combustion reactor. The bottom of the second partition unit is provided with a nitrogen stripping section, forming a gas partition combining the dense phase material seal and nitrogen stripping in the first riser section. The third partition unit is located between the steam reactor and the air reactor and is connected to the second riser section extending downward from the bottom of the steam reactor. The bottom of the third partition unit is provided with a nitrogen stripping section, forming a gas partition that combines the dense phase material seal and nitrogen stripping in the second riser section.

2. The chemical ring hydrogen production system according to claim 1, characterized in that, The nitrogen gas lift-off section in the first, second, and third partition units is equipped with a Johnson mesh with a V-shaped cross-section to disperse the nitrogen flow and increase the gas-solid contact area.

3. The chemical ring hydrogen production system according to claim 1, characterized in that, The first partition unit, the second partition unit, and the third partition unit are all equipped with interlocking control mechanisms. The interlocking control adopts a pressure difference interlocking control method to maintain a certain material level in the partition unit, so that the pressure in the corresponding partition unit is lower than that in the previous reactor and higher than that in the next reactor, ensuring the circulation of oxygen carrier while preventing nitrogen from entering the previous and / or next reactor.

4. The chemical ring hydrogen production system according to claim 1, characterized in that, Both the combustion reactor and the steam reactor are downflow fluidized bed reactors and have the same structure, including a settling section, a bed section, and a riser section.

5. The chemical ring hydrogen production system according to claim 4, characterized in that, The settling section is equipped with a first pressure measuring point to assess the overall pressure change of the system; the bed section is equipped with a second pressure measuring point, which consists of multiple points and is evenly spaced along the height of the bed to assess the change in the material level.

6. The chemical ring hydrogen production system according to claim 4, characterized in that, The fluidizing air inlet of the downflow fluidized bed reactor is located between the bed section and the riser section. A gas phase distribution plate is installed at the fluidizing air inlet to convert radial fluidizing air at a certain flow rate into axial fluidizing air that is uniformly sprayed upwards.

7. The chemical ring hydrogen production system according to claim 4, characterized in that, A gas filter is provided above the settling section to filter the gaseous products containing high-purity CO2 from the combustion reactor and the gaseous products containing high-purity H2 from the steam reactor.

8. The chemical ring hydrogen production system according to claim 1, characterized in that, The air reactor is an upward-flowing riser reactor, comprising a lower section, a middle expansion section, and an upper section.

9. The chemical ring hydrogen production system according to claim 8, characterized in that, The oxygen carrier inlet of the air reactor is located in the lower section and is arranged at an angle. The air introduced at the bottom of the lower section is used as fluidizing air to transport the oxygen carrier upward while the oxidation reaction is carried out. When the oxygen carrier reaches the middle expansion section, the flow rate decreases and the reaction time is extended.

10. A method for producing hydrogen through chemical cyclic ring synthesis, characterized in that, The application of the system as described in any one of claims 1 to 9 includes the following steps: A. The oxygen carrier, after being separated by cyclone separation and nitrogen stripping in the first partition unit, enters the combustion reactor from the side of the settling section; the raw material gas, as the bed fluidizing air, enters the bed section from the bottom, fluidizes the oxygen carrier in the combustion reactor and carries out the combustion reaction to obtain high-purity CO2. B. The oxygen carrier, after being transported by the dense phase in the bottom riser section of the combustion reactor and treated by nitrogen stripping in the second isolation unit, enters the steam reactor from the side of the settling section; water vapor enters the bed section from the bottom as the bed fluidizing air, fluidizing the oxygen carrier in the steam reactor and reacting it to obtain high-purity H2. C. The oxygen carrier, after being conveyed by the dense phase in the bottom riser section of the steam reactor and treated by the nitrogen stripping in the third isolation unit, enters from the lower section of the air reactor. Air is introduced at the feed point of the lower section as fluidizing air to transport the oxygen carrier upward while carrying out the oxidation reaction. The reaction time is extended in the middle expansion section, and the oxygen carrier is transported to the cyclone separator of the first isolation unit in the upper section.

11. The chemical cyclic hydrogen production method according to claim 10, characterized in that, The raw material gas in step A is a low-carbon alkane, which is one or more of methane, ethane, propane, and butane.

12. The chemical cyclic hydrogen production method according to claim 10, characterized in that, The active component of the oxygen carrier is one or more of Fe, Ni, Ce, Mn, and Cu; the additive is one or more of transition metals and rare earth metals; the oxygen carrier is shaped into microspheres for fluidized beds with an average particle size of 40–90 μm.

13. The chemical cyclic hydrogen production method according to claim 10, characterized in that, The operating conditions of the combustion reactor are as follows: reaction pressure is 0.1-1 MPa; reaction temperature is 700-1000℃; gas flow rate is 0.05-0.2 m / s.

14. The chemical cyclic hydrogen production method according to claim 10, characterized in that, The operating conditions of the steam reactor are as follows: reaction pressure is 0.1–1 MPa; reaction temperature is 400–800 °C; and gas flow rate is 0.1–0.3 m / s.

15. The chemical cyclic hydrogen production method according to claim 10, characterized in that, The operating conditions of the air reactor are as follows: reaction pressure is 0.1-1 MPa; reaction temperature is 700-1000℃; gas flow rate is 1-15 m / s.

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