Method and apparatus for producing co by thermochemical three-step cycle decomposition of co2
By employing a three-step thermochemical cyclic decomposition method involving manganese oxides and carbonates to decompose CO2, the problems of high-temperature material sintering and high energy consumption were solved, resulting in improved stability and economy.
Patent Information
- Application Number
- CN202310889868.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-19
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2043-07-19
AI Technical Summary
Existing thermochemical cyclic decomposition technology for CO2 production suffers from problems such as high-temperature material sintering and deactivation, poor reactor high-temperature resistance, high energy consumption, and poor techno-economic efficiency, which limit its development.
CO2 is decomposed in a thermochemical three-step cycle using manganese oxides and carbonates, including thermal oxygen decomposition reaction, CO generation reaction and regeneration reaction, reducing the reduction reaction temperature to below 1000℃, and separating CO and CO2 by pressure swing adsorption separation technology.
It effectively reduced the reaction temperature, improved the operational stability of the working fluid and reactor, reduced energy consumption, and enhanced technical and economic efficiency.
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Figure CN116969458B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of thermochemical carbon monoxide production technology, and in particular to a thermochemical three-step cyclic decomposition method and apparatus for producing CO from CO2. Background Technology
[0002] Rapid social development has propelled my country to become the world's largest industrial nation and second-largest economy, consequently making it a major energy consumer. While this enormous energy consumption, particularly the massive extraction and utilization of fossil fuels, has laid the foundation for my country's modern development and progress, it has also led to severe energy and environmental problems. Faced with immense pressure to conserve energy and reduce emissions, utilizing CO2 through effective technological pathways to process it into high-value-added fuels or chemical products like CO is an effective way to address these challenges.
[0003] Pyrolysis of CO2 is a direct way to convert it into CO, but the extremely high reaction temperature (>3000℃) and the difficulty in separating CO and O2 mixtures, as well as poor safety, make this technical approach difficult to apply. By introducing a circulating oxygen carrier, the one-step pyrolysis of CO2 is converted into a two-step indirect decomposition cycle using the oxidation and reduction reactions of the oxygen carrier. This reduces the temperature of the direct pyrolysis of CO2 to approximately 1500℃ and produces CO and O2 in stages, effectively overcoming the technical difficulties faced by the direct pyrolysis of CO2. However, this technical approach still has corresponding problems. First, the reduction reaction temperature of 1500℃ is still high. Under these high-temperature conditions, the metal oxide oxygen carrier is prone to sintering and deactivation, resulting in a continuous decline in recycling performance. On the other hand, the high reaction temperature also places almost stringent requirements on the high-temperature resistance of the reactor materials, making it difficult to guarantee the reliability of the reactor during long-term operation. Second, the low oxygen partial pressure operation of the reduction reaction requires maintenance through vacuum pumps or inert gas purging. Vacuum pumps have low efficiency when operating under low oxygen partial pressure conditions. Related research (Solar Energy, 2017, 141: 91-102) suggests that maintaining an oxygen partial pressure of 10 using vacuum is effective. -3 Below the bar, the efficiency is less than 10%. The low efficiency of the vacuum pump results in high energy consumption for thermochemical CO production cycles. While using inert gas to purge the reaction chamber to reduce oxygen partial pressure avoids the need for a vacuum pump, the large amount of inert gas entering the reactor along with the reactants requires additional heat absorption, leading to high energy consumption and poor techno-economic efficiency. These problems severely limit the development of thermochemical CO2 decomposition technology, necessitating the exploration of new technological approaches to overcome and solve these issues. Summary of the Invention
[0004] In view of the above problems, the present invention provides a thermochemical three-step cyclic decomposition method and apparatus for producing CO from CO2, so as to solve the problems of the shortcomings of the prior art.
[0005] This invention provides a thermochemical three-step cyclic decomposition method for producing CO from CO2, comprising: heating manganese trioxide to a first temperature and subjecting it to a thermal decomposition oxygen reaction at this temperature and atmospheric pressure to produce manganese tetroxide and oxygen; mixing the manganese tetroxide with carbonate and reacting it under a second temperature and atmospheric pressure to produce manganite, carbon dioxide, and carbon monoxide; placing the manganite in a carbon dioxide environment and subjecting it to a regeneration reaction with carbon dioxide under a third temperature and preset pressure to produce manganese trioxide and carbonate; separating the manganese trioxide and carbonate, and repeating the above steps to perform a cyclic reaction.
[0006] According to embodiments of this disclosure, the first temperature is 850–1000°C, the second temperature is 600–800°C, and the third temperature is 350–550°C.
[0007] According to embodiments of this disclosure, the preset pressure is 1 to 6.4 MPa.
[0008] According to embodiments of this disclosure, the method further includes: cooling the gaseous mixture of carbon dioxide and carbon monoxide; and separating the carbon dioxide and carbon monoxide by pressure swing adsorption separation technology.
[0009] According to an embodiment of this disclosure, the separation of manganese trioxide and carbonate includes: cooling the manganese trioxide and carbonate to obtain a solid mixture; utilizing the property that the carbonate is soluble in water and the manganese trioxide is insoluble in water, mixing the solid mixture with water and filtering to obtain the manganese trioxide; and performing crystallization and drying operations on the filtered solution to obtain the carbonate.
[0010] According to embodiments of this disclosure, the overall reaction of the method is the decomposition of 1 part carbon dioxide to produce 1 part carbon monoxide and 0.5 parts oxygen.
[0011] This disclosure also provides a thermochemical three-step cyclic decomposition CO2 to CO apparatus, applied to the method as described in any of the first aspects, comprising: a thermal decomposition oxygen reactor for heating manganese trioxide to a first temperature and conducting a thermal decomposition oxygen reaction at this temperature and atmospheric pressure to produce manganese tetroxide and oxygen; a carbon monoxide preparation reactor, connected upstream to the thermal decomposition oxygen reactor, for mixing the manganese tetroxide with carbonate and reacting under a second temperature and atmospheric pressure to produce manganite, carbon dioxide, and carbon monoxide; a regeneration reactor, connected upstream to the carbon monoxide preparation reactor, for placing the manganite in a carbon dioxide environment and conducting a regeneration reaction with carbon dioxide under a third temperature and preset pressure to produce manganese trioxide and carbonate; and a separation module, connected downstream to the thermal decomposition oxygen reactor and the carbon monoxide preparation reactor, for separating the manganese trioxide and carbonate, and conveying the manganese trioxide to the thermal decomposition oxygen reactor and the carbonate to the carbon monoxide preparation reactor for cyclic reaction.
[0012] According to embodiments of this disclosure, it further includes: a first cooler for cooling the oxygen.
[0013] According to embodiments of this disclosure, the device further includes: a second cooler, connected upstream to the carbon monoxide preparation reactor, for cooling the gaseous mixture of carbon dioxide and carbon monoxide; a first separation unit, connected upstream to the first cooler, for separating the carbon dioxide and carbon monoxide using pressure swing adsorption separation technology; and a heater, connected upstream to the first separation unit, an external carbon dioxide input terminal, and a regeneration reactor, and downstream to the regeneration reactor, for preheating the carbon dioxide separated by the first separation unit, the carbon dioxide input from the external carbon dioxide input terminal, and the remaining carbon dioxide in the regeneration reactor, and then inputting them into the regeneration reactor.
[0014] According to embodiments of this disclosure, it further includes: a third cooler, connected upstream to the regeneration reactor and downstream to the separation module for cooling the manganese trioxide and the carbonate to obtain a solid-phase mixture;
[0015] The above-described technical solutions employed in the embodiments of the present invention can achieve the following beneficial effects:
[0016] The thermochemical cyclic decomposition method for producing CO2 disclosed in this invention breaks through the traditional two-step reaction decomposition mode of CO2 to produce CO using a single type of cyclic oxygen carrier, and innovatively utilizes manganese oxides and carbonates to perform thermochemical three-step cyclic decomposition of CO2 to produce CO.
[0017] The thermochemical cycle decomposition method for producing CO from CO2 disclosed in this invention effectively reduces the high reduction reaction temperature (below 1000℃) of traditional thermochemical cycles, improves the operational stability of the working fluid and reactor, and overcomes the problems of high energy consumption and poor technical and economic efficiency of traditional thermochemical cycles with low oxygen partial pressure reactions. Attached Figure Description
[0018] To gain a more complete understanding of the invention and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:
[0019] Figure 1 This is a process flow diagram of the three-step cyclic decomposition method for producing CO from manganese oxide and sodium carbonate in the first embodiment of the present invention.
[0020] Figure 2 This is a process flow diagram of the three-step cyclic decomposition method for producing CO from manganese oxide and potassium carbonate in the second embodiment of the present invention.
[0021] Figure 3 The diagram below shows the process flow chart of the three-step cyclic decomposition method for producing CO2 from manganese oxide and sodium carbonate using solar thermochemical methods, as described in the third embodiment of the invention. Detailed Implementation
[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.
[0024] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.
[0025] This invention provides a thermochemical three-step cyclic decomposition method for producing CO from CO2, comprising the following steps:
[0026] (1) Manganese trioxide (Mn2O3) is heated to a first temperature of 850-1000℃, and at this temperature and at normal pressure, a thermal deoxygenation reaction occurs to produce manganese trioxide (Mn3O4) and oxygen (O2). The reaction equation is as follows:
[0027] 3Mn₂O₃→2Mn₃O₄+0.5O₂
[0028] This process is endothermic, with a reaction temperature of 850–1000℃ and atmospheric pressure. The generated Mn3O4 separates from the O2 gas, and pure O2 is obtained directly upon cooling.
[0029] (2) Manganese tetroxide (Mn3O4) is mixed with carbonate (A2CO3, where A can be a metal element such as potassium or sodium) and reacted at a second temperature of 600-800℃ and under normal pressure to produce manganite (AMnO2), carbon dioxide (CO2) and carbon monoxide (CO). The reaction equation is as follows:
[0030] 2Mn3O4+3A2CO3→6AMnO2+2CO2+CO
[0031] This process is endothermic, with a reaction temperature of 600–800℃ and atmospheric pressure. The resulting solid-phase reaction product, manganite (AMnO2), is separated from the gaseous product, CO2, by gas-solid separation. The gaseous mixture of carbon dioxide and carbon monoxide is cooled, and then separated by pressure swing adsorption (PSA) separation technology.
[0032] (3) The permanganate (AMnO2) obtained in the above process is placed in a carbon dioxide (CO2) environment. Under the conditions of a third temperature of 350-550℃ and a preset pressure, the permanganate undergoes a regeneration reaction with carbon dioxide to produce manganese trioxide (Mn2O3) and carbonate (A2CO3). The reaction equation is as follows:
[0033] 6AMnO2 + 3CO2 → 3Mn2O3 + 3A2CO3
[0034] This process is exothermic, with reaction conditions ranging from 350 to 550°C and a preset pressure of atmospheric or low to medium pressure, specifically 1 to 6.4 MPa. Manganese trioxide and carbonate are cooled to obtain a solid mixture. Taking advantage of the fact that carbonate is soluble in water while manganese trioxide is insoluble, the solid mixture is mixed with water and filtered to obtain manganese trioxide (Mn₂O₃). The filtered solution is then crystallized and dried to obtain carbonate (A₂CO₃).
[0035] In this embodiment, manganese trioxide and carbonate are separated, and the above steps are repeated to achieve a cyclic reaction. This thermochemical three-step cyclic decomposition method for producing CO from manganese oxide and carbonate involves a CO2 decomposition reaction, where 1 part of carbon dioxide decomposes to produce 1 part of carbon monoxide and 0.5 parts of oxygen, i.e., CO2 → CO + 0.5O2.
[0036] refer to Figures 1-3 In another aspect, this disclosure provides a thermochemical three-step cyclic decomposition CO2 to CO apparatus, which uses the above-mentioned method and includes a thermal oxygen decomposition reactor 01, a carbon monoxide preparation reactor 04, a regeneration reactor 08, and a separation module.
[0037] The thermal decomposition oxygen reactor 01 is used to heat manganese trioxide (Mn2O3) to a first temperature, and at this temperature and at normal pressure, a thermal decomposition oxygen reaction occurs to produce manganese tetroxide (Mn3O4) and oxygen (O2).
[0038] The carbon monoxide preparation reactor 04 is connected upstream to the thermal deoxygenation reactor 01, which is used to mix manganese tetroxide (Mn3O4) with carbonate (A2CO3) and react them under a second temperature and atmospheric pressure to produce manganite (AMnO2), carbon dioxide (CO2) and carbon monoxide (CO).
[0039] Upstream of the regeneration reactor 08 is a carbon monoxide preparation reactor 04, which is used to place manganese sulfite (AMnO2) in a carbon dioxide (CO2) environment. Under the conditions of a third temperature and a preset pressure, manganese sulfite (AMnO2) undergoes a regeneration reaction with carbon dioxide (CO2) to produce manganese trioxide (Mn2O3) and carbonate (A2CO3).
[0040] The downstream of separation module 03 is connected to the thermal desorption oxygen reactor 01 and the carbon monoxide preparation reactor 04. It is used to separate manganese trioxide (Mn₂O₃) and carbonate (A₂CO₃). Utilizing the property that carbonate is soluble in water while manganese trioxide (Mn₂O₃) is insoluble, the solid mixture is mixed with water, filtered to obtain manganese trioxide (Mn₂O₃), and the filtered solution is crystallized and dried to obtain carbonate (A₂CO₃). The manganese trioxide is then fed to the thermal desorption oxygen reactor 01, and the carbonate (A₂CO₃) is fed to the carbon monoxide preparation reactor 04 for a cyclic reaction.
[0041] The device also includes a first cooler O2 for cooling oxygen (O2).
[0042] The device also includes a second cooler 05, connected upstream to a carbon monoxide preparation reactor 04, for cooling a gaseous mixture of carbon dioxide (CO2) and carbon monoxide (CO); a first separation unit 06, connected upstream to the first cooler 05, for separating carbon dioxide (CO2) and carbon monoxide (CO) using pressure swing adsorption separation technology; and a heater 09, connected upstream to the first separation unit 06, an external carbon dioxide input terminal, and a regeneration reactor 08, and downstream to the regeneration reactor 08, for preheating the carbon dioxide (CO2) separated by the first separation unit 06, the carbon dioxide (CO2) input from the external carbon dioxide input terminal, and the remaining carbon dioxide (CO2) in the regeneration reactor 08, and then inputting them into the regeneration reactor 08.
[0043] The device also includes a third cooler 07, which is connected upstream to a regeneration reactor 08 and downstream to a separation module 03, for cooling manganese trioxide (Mn2O3) and carbonate (A2CO3) to obtain a solid mixture.
[0044] The following detailed description of the thermochemical three-step cyclic decomposition CO2 to CO apparatus and method provided by the present invention is based on specific embodiments.
[0045] Example 1
[0046] This embodiment uses sodium carbonate (Na2CO3) as the circulating working fluid, which participates in a thermochemical cycle together with manganese oxides to achieve CO2 decomposition to CO. The reaction equation for the thermochemical three-step cyclic decomposition of CO2 to CO using manganese oxides and sodium carbonate is as follows:
[0047] Thermal decomposition of oxygen reaction: 3Mn₂O₃ → 2Mn₃O₄ + 0.5O₂
[0048] CO production reaction: 2Mn3O4 + 3Na2CO3 → 6NaMnO2 + 2CO2 + CO
[0049] Regeneration reaction: 6NaMnO2 + 3CO2 → 3Mn2O3 + 3Na2CO3
[0050] The flowchart corresponding to the above-mentioned thermochemical three-step cycle method of manganese oxide and sodium carbonate is as follows: Figure 1 As shown.
[0051] First, Mn2O3 enters the thermal oxygen release reactor 01 and is heated to 850-1000℃, where it undergoes an oxygen release reaction to produce O2 and Mn3O4.
[0052] The obtained O2 is cooled by the first cooler O2 to obtain pure oxygen product. The solid-phase reaction product Mn3O4 is mixed with the separated Na2CO3 in the carbon monoxide preparation reactor O4 and heated.
[0053] When the temperature reaches 600-800℃, the two react chemically to produce sodium manganite (NaMnO2) and a gaseous mixture of CO2 and CO.
[0054] After being cooled by the second cooler 05, the CO2 and CO gaseous mixture enters the first separation unit 06 for separation (such as pressure swing adsorption separation) to obtain pure CO2 and CO products.
[0055] The separated CO2 is mixed with the CO2 feedstock and unreacted CO2 in regeneration reactor 08, and after preheating in heater 09, it enters regeneration reactor 08 to undergo a regeneration reaction with NaMnO2 obtained in carbon monoxide preparation reactor 04 at 350–550°C, yielding a solid-phase mixture of Na2CO3 and Mn2O3. If this reaction needs to occur under medium or low pressure conditions, a compressor can be added at the inlet of reactor 08 to achieve a medium or low pressure reaction.
[0056] Unconverted CO2 in regeneration reactor 08 is recycled to heater 09 for reuse. The Na2CO3 and Mn2O3 solid mixed product obtained through the regeneration reaction enters the third cooler 07 for cooling.
[0057] The cooled solid-phase mixture of Na₂CO₃ and Mn₂O₃ enters separation module 03 for separation, yielding pure Na₂CO₃ and Mn₂O₃. Based on the water solubility characteristics of Na₂CO₃ and Mn₂O₃, separation module 03 can utilize a dissolution-separation-drying technique. Specifically, after mixing the solid-phase mixture with water, Na₂CO₃ dissolves in the water, while pure Mn₂O₃ is obtained through precipitation and drying. Then, pure Na₂CO₃ is obtained again by crystallizing and drying the Na₂CO₃ solution.
[0058] The pure Mn2O3 and Na2CO3 obtained by the separation module 03 are recycled back to the oxygen release reactor 01 and the carbon monoxide preparation reactor 04 for a new cycle.
[0059] Example 2
[0060] This embodiment uses potassium carbonate (K2CO3) as the circulating working fluid, which participates in a thermochemical cycle together with manganese oxides to achieve CO2 decomposition to CO. The reaction equation for the thermochemical three-step cyclic decomposition of CO2 to CO using manganese oxides and potassium carbonate is as follows:
[0061] Thermal decomposition of oxygen reaction: 3Mn₂O₃ → 2Mn₃O₄ + 0.5O₂
[0062] CO production reaction: 2Mn3O4 + 3K2CO3 → 6KMnO2 + 2CO2 + CO
[0063] Regeneration reaction: 6KMnO2 + 3CO2 → 3Mn2O3 + 3K2CO3
[0064] The flowchart corresponding to the above-mentioned thermochemical cycle method using manganese oxide and potassium carbonate is as follows: Figure 2 As shown.
[0065] First, Mn2O3 enters the thermal oxygen release reactor 01 and is heated to 850-1000℃, where it undergoes an oxygen release reaction to produce O2 and Mn3O4.
[0066] The obtained O2 is cooled by the first cooler O2 to obtain pure oxygen product. The solid-phase reaction product Mn3O4 is mixed and heated with the separated K2CO3 in the carbon monoxide preparation reactor O4.
[0067] When the temperature reaches 600-800℃, the two react chemically to produce potassium manganite (KMnO2) and a gaseous mixture of CO2 and CO.
[0068] After being cooled by the second cooler 05, the CO2 and CO gaseous mixture enters the first separation unit 06 for separation (such as pressure swing adsorption separation) to obtain pure CO2 and CO products.
[0069] The separated CO2 is mixed with the CO2 feedstock and unreacted CO2 in regeneration reactor 08, and after preheating in heater 09, it enters regeneration reactor 08 to undergo a regeneration reaction with KMnO2 obtained from carbon monoxide preparation reactor 04 at 350–550°C, yielding a solid-phase mixture of K2CO3 and Mn2O3. If this reaction needs to occur under medium or low pressure conditions, a compressor can be added at the inlet of reactor 08 to achieve a medium or low pressure reaction.
[0070] Unconverted CO2 in regeneration reactor 08 is recycled to heater 09 for reuse. The solid-phase mixed product of K2CO3 and Mn2O3 obtained through the regeneration reaction enters the third cooler 07 for cooling.
[0071] The cooled solid-phase mixture of K₂CO₃ and Mn₂O₃ enters separation module 03 for separation, yielding pure K₂CO₃ and Mn₂O₃. Based on the water solubility characteristics of K₂CO₃ and Mn₂O₃, separation module 03 can utilize a dissolution-separation-drying technique. Specifically, after the solid-phase mixture is mixed with water, K₂CO₃ dissolves in the water, while pure Mn₂O₃ is obtained through precipitation and drying. Then, pure K₂CO₃ is obtained again by crystallizing and drying the K₂CO₃ solution.
[0072] The pure Mn2O3 and K2CO3 obtained by the separation module 03 are recycled back to the oxygen release reactor 01 and the carbon monoxide preparation reactor 04 for a new cycle.
[0073] Example 3
[0074] The provided method for producing CO from manganese oxides and carbonates via a three-step thermochemical cycle decomposition of CO2 consists of two endothermic reactions (thermal decomposition of oxygen and CO production) and one exothermic reaction (regeneration reaction). The heat source required for the endothermic reactions can be provided by fuel combustion, electric heating, and concentrated solar power. This embodiment, based on the three-step thermochemical cycle decomposition of manganese oxides and sodium carbonate to produce CO2, provides an implementation scheme utilizing concentrated solar power to provide heat for the two endothermic reactions and the necessary heating process, such as... Figure 3 As shown.
[0075] Solar energy is concentrated into thermal energy using a tower-type or dish-type concentrating solar energy device 10, which is used to drive the oxygen release reactor 01. Mn2O3 is heated to 850-1000℃ in the oxygen release reactor to undergo a thermal deoxygenation reaction, producing Mn3O4 and O2.
[0076] The obtained O2 is cooled by the first cooler 02 to obtain pure oxygen product. The solid-phase reaction product Mn3O4 is mixed with the separated Na2CO3 in the carbon monoxide preparation reactor 04, and solar energy is concentrated by the concentrating solar energy device 11 to provide heat energy for the CO production reaction.
[0077] The gaseous reaction mixture of CO2 and CO produced by the carbon monoxide preparation reactor 04 is cooled by the second cooler 05 and then enters the first separation unit 06 for separation to obtain pure CO2 and CO.
[0078] The separated CO2 is mixed with the CO2 feedstock and unreacted CO2 in regeneration reactor 08, and after preheating in heater 09, it enters regeneration reactor 08 to undergo a regeneration reaction with NaMnO2 obtained in carbon monoxide preparation reactor 04 at 350–550°C, yielding a solid-phase mixture of Na2CO3 and Mn2O3. If this reaction needs to occur under medium or low pressure conditions, a compressor can be added at the inlet of reactor 08 to achieve a medium or low pressure reaction.
[0079] Unconverted CO2 in regeneration reactor 08 is recycled to heater 09 for reuse. The Na2CO3 and Mn2O3 solid mixed product obtained through the regeneration reaction enters the third cooler 07 for cooling.
[0080] The cooled solid-phase mixture of Na₂CO₃ and Mn₂O₃ enters separation module 03 for separation, yielding pure Na₂CO₃ and Mn₂O₃. Based on the solubility characteristics of Na₂CO₃ and Mn₂O₃ in water, separation module 03 can utilize techniques such as dissolution-separation-drying.
[0081] The pure Mn2O3 and Na2CO3 substances obtained by the separation module 03 are recycled back to the oxygen release reactor 01 and the carbon monoxide preparation reactor 04, respectively, and are reheated by concentrated solar energy to 850-1000℃ and 600-800℃ for a new cycle.
[0082] The present invention discloses a thermochemical cycle decomposition device and method for CO production from CO2, which breaks through the traditional two-step reaction decomposition mode of CO2 production from a single type of circulating oxygen carrier, and innovatively utilizes manganese oxides and carbonates for thermochemical three-step cycle decomposition of CO2 to CO. The device and method effectively reduce the high reduction reaction temperature of traditional thermochemical cycles (below 1000℃ from 1500℃), improve the operational stability of the working medium and reactor, and overcome the problems of high energy consumption and poor technical and economic efficiency of traditional thermochemical cycles with low oxygen partial pressure reactions.
[0083] Those skilled in the art will understand that the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.
[0084] Although the invention has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. Therefore, the scope of the invention should not be limited to the above embodiments, but should be determined not only by the appended claims but also by their equivalents.
Claims
1. A thermochemical three-step cyclic decomposition method for producing CO from CO2, characterized in that, include: Manganese trioxide is heated to a first temperature, and at this temperature and normal pressure, it undergoes a thermal decomposition oxygen reaction to produce manganese trioxide and oxygen. The manganese tetroxide was mixed with carbonate and reacted under a second temperature and atmospheric pressure to produce manganite, carbon dioxide and carbon monoxide. The manganite is placed in a carbon dioxide environment, and under a third temperature and preset pressure conditions, the manganite undergoes a regeneration reaction with carbon dioxide to produce manganese trioxide and the carbonate. The manganese trioxide and the carbonate were cooled to obtain a solid mixture; Taking advantage of the fact that the carbonate is soluble in water and the manganese trioxide is insoluble in water, the solid mixture is mixed with water and then filtered to obtain the manganese trioxide. The filtered solution was subjected to crystallization and drying to obtain the carbonate. Repeat the above steps to carry out the cyclic reaction.
2. The method according to claim 1, characterized in that, The first temperature is 850~1000℃, the second temperature is 600~800℃, and the third temperature is 350~550℃.
3. The method according to claim 1, characterized in that, The preset pressure is 1~6.4 MPa.
4. The method according to claim 1, characterized in that, The method further includes: Cool the gaseous mixture of the carbon dioxide and the carbon monoxide; The carbon dioxide and carbon monoxide are separated by pressure swing adsorption (PSA) separation technology.
5. The method according to claim 1, characterized in that, The overall reaction of the method is that 1 part carbon dioxide decomposes to produce 1 part carbon monoxide and 0.5 parts oxygen.
6. A thermochemical three-step cyclic decomposition apparatus for producing CO from CO2, applied to the method described in any one of claims 1 to 5, characterized in that, include: The thermal decomposition oxygen reactor (01) is used to heat manganese trioxide to a first temperature and at this temperature and atmospheric pressure to undergo a thermal decomposition oxygen reaction to produce manganese tetroxide and oxygen. A carbon monoxide preparation reactor (04) is connected upstream to the thermal oxygen decomposition reactor (01) for mixing manganese tetroxide with carbonate and reacting under a second temperature and atmospheric pressure to generate manganite, carbon dioxide and carbon monoxide. The regeneration reactor (08) is connected upstream to the carbon monoxide preparation reactor (04) for placing the manganese salt in a carbon dioxide environment. Under the conditions of a third temperature and a preset pressure, the manganese salt undergoes a regeneration reaction with carbon dioxide to produce manganese trioxide and the carbonate. The third cooler (07) is used to cool the manganese trioxide and the carbonate to obtain a solid mixture; The separation module (03) is connected downstream to the thermal deoxygenation reactor (01) and the carbon monoxide preparation reactor (04). It is used to utilize the properties that the carbonate is soluble in water and the manganese trioxide is insoluble in water to mix the solid mixture with water, filter the manganese trioxide, crystallize and dry the filtered solution to obtain the carbonate, and then transport the manganese trioxide to the thermal deoxygenation reactor (01) and the carbonate to the carbon monoxide preparation reactor (04) for recycling.
7. The apparatus according to claim 6, characterized in that, Also includes: The first cooler (02) is used to cool the oxygen.
8. The apparatus according to claim 6, characterized in that, Also includes: The second cooler (05) is connected upstream to the carbon monoxide preparation reactor (04) and is used to cool the gaseous mixture of carbon dioxide and carbon monoxide; The first separation unit (06) is connected upstream to the first cooler (05) and is used to separate the carbon dioxide and the carbon monoxide by pressure swing adsorption separation technology; The heater (09) is connected upstream to the first separation unit (06), the external carbon dioxide input terminal and the regeneration reactor (08), and downstream to the regeneration reactor (08). It is used to preheat the carbon dioxide separated by the first separation unit (06), the carbon dioxide input by the external carbon dioxide input terminal and the remaining carbon dioxide in the regeneration reactor (08), and input it into the regeneration reactor (08).