Integrated CO2 in-situ reforming system

Abstract

This invention discloses an integrated CO2 in-situ reforming system. By constructing a parallel multi-chamber system, it enables the circulation of reforming catalyst particles or the interactive use of reforming catalyst beds. This system can directly capture CO2 in industrial flue gas / tail gas in situ and complete the in-situ catalytic reforming conversion of the captured CO2 within the same system. This eliminates the need for desorption and purification of the captured CO2 before off-site transportation and conversion, significantly simplifying the processing flow, reducing overall energy consumption and equipment investment, and greatly improving CO2 conversion efficiency and resource utilization rate. The system structure of this invention is simple, the process is short, and it is easy to scale up and apply.

Description

Technical Field

[0001] This invention relates to equipment for treating carbon dioxide flue gas, specifically to an integrated CO2 in-situ reforming system, belonging to the field of carbon dioxide and oxygen treatment technology. Background Technology

[0002] Global warming and greenhouse gas control have become major challenges to the sustainable development of human society. Large-scale carbon dioxide (CO2) emissions are a core factor contributing to the exacerbation of the greenhouse effect. Achieving efficient CO2 emission reduction and resource recycling is a key path to promoting energy structure transformation and green upgrading of high-carbon industries. CO2 molecules have a stable chemical structure and strong inertness, making direct conversion difficult. Catalytic conversion of CO2 into carbon monoxide (CO) is an important technological route for CO2 resource utilization. As a crucial basic chemical platform molecule, CO is a core raw material for syngas, methanol, acetic acid, Fischer-Tropsch fuels, and various fine chemicals. It can be widely used in chemical, energy, and metallurgical fields, and can construct a closed-loop carbon cycle system of "CO2 capture-catalytic conversion-resource utilization," reducing fossil resource consumption and greenhouse gas emissions at the source.

[0003] Existing processes generally employ a segmented approach: independent CO2 capture, purification, off-site transportation, and separate catalytic conversion. This fails to achieve integrated coupling of in-situ CO2 enrichment and catalytic conversion in industrial flue gas / tail gas. The process is lengthy, requiring additional intermediate units such as decarbonization towers, distillation purification, compression, and storage, resulting in high energy consumption, significant carbon loss, and low treatment efficiency. Furthermore, the long-distance transportation, storage, and pressurization of CO2 significantly increase equipment investment and operating costs. In addition, existing processes often focus solely on the catalytic conversion of CO2, resulting in limited single-pass CO2 conversion rates. Unconverted CO2 is directly emitted or inefficiently vented, leading to low carbon resource utilization. Summary of the Invention

[0004] To address the problems of long and inefficient processes in existing CO2 capture and recovery treatment of flue gas, this invention provides an integrated CO2 in-situ reforming system. This invention constructs a parallel multi-chamber system, enabling the circulation of reforming catalyst particles or the interactive use of reforming catalyst beds. It can directly capture CO2 in industrial flue gas / tail gas in situ and complete the in-situ catalytic reforming conversion of the captured CO2 within the same system. This eliminates the need for desorption and purification of the captured CO2 before transporting it to another location for conversion, significantly simplifying the treatment process, reducing overall energy consumption and equipment investment, and greatly improving CO2 conversion efficiency and CO2 resource utilization rate.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] An integrated CO2 in-situ reforming system, comprising a housing and an inner cavity. The inner cavity is divided from top to bottom into a reforming cavity and a synthesis cavity, or the inner cavity is divided horizontally into multiple (at least two) unit cavities.

[0007] The reforming chamber and the synthesis chamber are connected. A carbon-containing gas input pipe and a reformed gas output pipe are connected to the reforming chamber. A reducing gas input pipe and a synthesis gas output pipe are connected to the synthesis chamber. A heating mechanism is installed inside the synthesis chamber. Both the reforming chamber and the synthesis chamber are filled with reforming catalyst particles.

[0008] The multiple unit chambers are not interconnected, and each unit chamber independently has a heating mechanism and a reforming catalyst bed. At least one unit chamber is connected to a carbon-containing gas input pipe and a reforming gas output pipe. At least one unit chamber is also connected to a reducing gas input pipe and a synthesis gas output pipe.

[0009] Preferably, the reforming chamber and the synthesis chamber are connected by multiple flat channels that are wide at the ends and narrow in the middle. Alternatively, the reforming chamber and the synthesis chamber can be connected by multiple evenly distributed round or square tubes.

[0010] Preferably, a uniform discharge mechanism is provided at the bottom discharge port of the synthesis chamber. This mechanism consists of multiple evenly spaced distribution cones, each wider at the bottom than the top. The inclination angle of the cone surface is greater than the angle of repose of the reforming catalyst particles. Preferably, the inclination angle of the cone surface is 2-10° greater than the angle of repose of the reforming catalyst particles. Preferably, the distribution cone is a square pyramid, and the distance between the distribution cones and between the distribution cone and the inner wall of the synthesis chamber is 20-80 mm. The bottom side length of the distribution cone is 100-800 mm.

[0011] Preferably, the bottom discharge port of the synthesis chamber is connected to the top feed port of the reforming chamber via a catalyst circulation conveying device. The reforming catalyst particles circulate between the reforming chamber and the synthesis chamber via the catalyst circulation conveying device. Preferably, the catalyst circulation conveying device is equipped with a material temperature sensor (e.g., a thermocouple) and a material flow regulating valve (e.g., a rotary valve).

[0012] Preferably, the heating mechanism is an electric heating wire, an electric heating plate, a hot air duct network, or an oxygen supply duct network.

[0013] Preferably, gas temperature detectors (e.g., thermocouples) and gas flow regulating valves (e.g., pneumatic regulating valves) are independently installed on the carbon gas input pipeline, reforming gas output pipeline, reducing gas input pipeline, and synthesis gas output pipeline.

[0014] Preferably, the heating mechanism is a hot air duct network, which includes an inlet duct, a heat exchange tube array, and an exhaust duct connected in series. The heat exchange tube array is located inside the synthesis chamber or is independently installed in each unit chamber. The inlet duct and exhaust duct are located outside the shell, and the inlet duct is connected to the hot air furnace. Preferably, the heat exchange tube array in each unit chamber is connected to the inlet duct and exhaust duct respectively through independent inlet branch ducts and exhaust branch ducts.

[0015] Preferably, the heating mechanism is an oxygen supply network, which includes a main oxygen supply pipeline and several oxygen supply branch pipes. The main oxygen supply pipeline is connected to the synthesis chamber through several oxygen supply branch pipes, or the main oxygen supply pipeline is connected to each unit chamber through several oxygen supply branch pipes respectively. Each of the main oxygen supply pipeline and several oxygen supply branch pipes is independently equipped with a throttling valve.

[0016] Preferably, each unit cavity is equipped with a unit intake branch pipe and a unit exhaust branch pipe. All unit cavities are arranged horizontally along their inner dimensions, with the following configuration: the unit intake branch pipes of all odd-numbered unit cavities are connected to the first main intake pipe, and the unit exhaust branch pipes of all odd-numbered unit cavities are connected to the first main exhaust pipe. The unit intake branch pipes of all even-numbered unit cavities are connected to the second main intake pipe, and the unit exhaust branch pipes of all even-numbered unit cavities are connected to the second main exhaust pipe. Both ends of the first and second main intake pipes are connected to the carbon-containing gas input pipe and the reducing gas input pipe, respectively, via independent valve pipes. Both ends of the first and second main exhaust pipes are connected to the reforming gas output pipe and the synthesis gas output pipe, respectively, via independent valve pipes.

[0017] Preferably, the reforming catalyst particles and the reforming catalyst bed are calcium oxide and / or lanthanum manganese iron nickel composite oxide.

[0018] Preferably, the structural formula of the lanthanum manganese iron-nickel composite oxide is LaMn. x Fe y Ni z O3, where: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5. Preferably, 0.1≤x≤0.3, 0.3≤y≤0.8, 0.1≤z≤0.4. More preferably, 0.15≤x≤0.25, 0.45≤y≤0.65, 0.2≤z≤0.3. x+y+z=1.

[0019] In this invention, the integrated CO2 in-situ reforming system has a multi-chamber structure, specifically consisting of a reforming chamber and a synthesis chamber connected in series from top to bottom, or at least two parallel, non-communicating unit chambers arranged horizontally. Through its multi-chamber (at least two) design, combined with reforming catalyst particles circulating between the reforming and synthesis chambers or reforming catalyst beds fixed within each unit chamber, the system can continuously achieve in-situ reforming and conversion of carbon dioxide flue gas, meeting the production requirements of an integrated "CO2 in-situ capture-in-situ catalytic reforming" coupled process. In other words, the system provided by this invention can integrate the two core steps of CO2 adsorption and capture, and catalytic cracking conversion, into a single system, eliminating the need for additional intermediate steps such as CO2 purification, compression, and storage. It can directly complete the in-situ enrichment and conversion of CO2 in carbon-containing gases within the system, effectively shortening the process flow and reducing energy consumption and carbon loss in intermediate processes.

[0020] In this invention, when the multi-chamber structure of the system is an arrangement of a reforming chamber and a synthesis chamber arranged vertically, the reforming chamber and the synthesis chamber are interconnected. The reforming chamber is connected to a carbon-containing gas input pipe and a reformed gas output pipe, while the synthesis chamber is connected to a reducing gas input pipe and a synthesis gas output pipe. A heating mechanism is installed inside the synthesis chamber. Both the reforming chamber and the synthesis chamber are filled with reforming catalyst particles. After the carbon-containing gas enters the reforming chamber, CO2 is adsorbed by the catalyst and catalytically converted into CO. The resulting reformed gas is discharged through the reformed gas output pipe. The deactivated catalyst enters the synthesis chamber and is regenerated in situ by the reducing gas (CH4) under heating conditions. At the same time, CH4 is converted into synthesis gas (CO+H2). The generated synthesis gas is discharged through the synthesis gas output pipe. The regenerated reforming catalyst particles are sent back to the reforming chamber for recycling through a catalyst circulation conveying device (e.g., a belt conveyor or a chain bucket machine) to continuously achieve catalytic reforming of CO2 in the flue gas.

[0021] In this invention, the circulation rate of the reforming catalyst particles is controlled by the discharge rate at the bottom of the synthesis section. The catalyst circulation rate is closely related to the reforming chamber (denoted as t5, generally 700~900℃, preferably 750~870℃, more preferably 800~840℃), the reforming chamber reaction temperature (denoted as t6, generally 600~800℃, preferably 630~750℃, more preferably 660~700℃), the catalyst specific heat capacity Cp4 (kJ / (kg·K)), the flow rate q1 of carbon-containing gas (e.g., blast furnace gas), the CO2 volume concentration d% in the carbon-containing gas, the CO2 capture and cracking rate e% in the reforming chamber, the isobaric specific heat capacity Cp1 of the carbon-containing gas (kJ / (kmol·K)), the inlet temperature t1 (℃) of the carbon-containing gas, and the heat release Q1 of the catalytic reforming reaction. If the heat loss of the reforming chamber is 2%, and the minimum circulation rate is m0 (t / h), then:

[0022] q1×d%×e%×1000 / 22.4×Q1×(1-2%)=1000×m0×Cp4×(t6-t5)+ q1×Cp1×(t5-t1).

[0023] Summarized as follows:

[0024] m0=[0.044×q1×d%×e%×Q1-0.001×q1×Cp1×(t5-t1)] / [Cp4×(t6-t5)].

[0025] Therefore, in actual operation, considering operational safety and heat conservation, the actual circulation volume m is:

[0026] m = m0 × (1.05 ~ 1.1).

[0027] In this invention, the connecting section (or transition section) between the reforming chamber and the synthesis chamber is designed with a smaller diameter than both the outlet and inlet diameters of the reforming chamber and the synthesis chamber. It is generally composed of multiple evenly arranged vertical pipes (round or square pipes) or multiple flat channels that are wide at the top and bottom and narrow in the middle. Through the design of the variable diameter transition section, on the one hand, the uniform downward movement of the reforming catalyst particles can be achieved, and on the other hand, a material seal of a certain height can be formed between the reforming chamber and the synthesis chamber, thereby avoiding gas leakage between the reforming chamber and the synthesis chamber (gas leakage rate ≤ 0.1%).

[0028] Furthermore, a uniform discharge mechanism is provided at the bottom of the synthesis chamber to ensure uniform and overall settling of the catalyst material. The main features of the uniform discharge mechanism are: ① The angles of all four faces of each distribution cone are greater than the angle of repose of the catalyst particles by 1~10° (preferably greater than 5°); ② The length and width of the bottom surface of the distribution cone are both between 500mm and 800mm; ③ The bottom surfaces of all distribution cones are located in the same horizontal plane; ④ The gaps between the distribution cones and between the distribution cones and the inner wall of the synthesis chamber are equal, generally controlled between 20mm and 80mm (because the diameter of the catalyst particles is generally less than 20mm).

[0029] In this invention, when the multi-chamber structure of the system is a horizontally separated multi-unit chamber structure, the unit chambers are not interconnected. Each unit chamber is independently equipped with a heating mechanism and a reforming catalyst bed (the bed is generally non-flowing, but can be replaced as a whole). At least one unit chamber is used for the catalytic reforming process of CO2 in flue gas, connected to the carbon-containing gas input pipeline and the reformed gas output pipeline. At least one unit chamber is used for the catalyst regeneration process, connected to the reducing gas input pipeline and the synthesis gas output pipeline. By switching the working state of different unit chambers (alternating operation), the in-situ reforming process of CO2 is continuously realized, significantly improving the CO2 treatment efficiency. For example, by numbering the individual unit chambers horizontally, all odd-numbered unit chambers are grouped into one group, and all even-numbered unit chambers into another. The functions of the odd-numbered and even-numbered unit chambers are alternated through pipeline switching: when the odd-numbered unit chambers are connected to carbon-containing gas via the first intake pipe, CO2 is captured and catalytically reformed in situ, and the resulting reformed product is discharged through the first exhaust pipe into the reformed gas output pipe; simultaneously, the even-numbered unit chambers are connected to reducing gas via the second intake pipe, completing the in-situ reduction and regeneration of the deactivated catalyst, and the resulting syngas is discharged through the second exhaust pipe into the syngas output pipe; once the catalyst activity in the odd-numbered unit chambers drops to a set value, the gas path can be switched via the valve pipeline, allowing the even-numbered unit chambers to connect to carbon-containing gas for CO2 capture and reforming, while the odd-numbered unit chambers connect to reducing gas for catalyst reduction and regeneration. This cyclical alternation ensures a continuous and stable output of products from the entire system, eliminating the need for catalyst replacement and significantly improving the system's continuous operating efficiency.

[0030] In this invention, the number of unit chambers should preferably be ≥10. The unit chambers are isolated by high-temperature resistant steel plates, designed to withstand temperatures up to 950℃ (reaction temperature <850℃). In the first reaction cycle, unit chambers with odd-numbered serial numbers (i.e., chambers 1, 3, 5, 7, 9, ...) are used as catalytic reforming units, while unit chambers with even-numbered serial numbers (i.e., chambers 2, 4, 6, 8, 10, ...) are used as catalyst regeneration units. In the next cycle, the functions are exchanged, and this cycle repeats. Generally, the length of a unit chamber is am (typically 10m); the catalyst bed height is bm (typically 10m). Each unit chamber has a certain height (typically 0.6m~1m) of space reserved at both ends of the catalyst bed as an inlet and outlet chamber, with a width of cm (typically 0.15-0.30m). Let q0 be the amount of carbon-containing gas (e.g., blast furnace gas) that can be processed in any unit chamber, and d% be the CO2 concentration of the carbon-containing gas, with a capture and cracking rate of e%. Then, the calorific value Q1 of the catalytic reforming in this chamber is:

[0031] Q1×q0×d%×e%×1000 / 22.4=44.64×Q1×q0×d%×e% kJ / h.

[0032] Heat transfer between the catalytic reforming unit and the catalyst regeneration unit mainly occurs through solid-state heat conduction, convective heat transfer of carbon-containing gases, and radiative heat transfer. For engineering approximations, neglecting the thermal resistance of the steel partition, we have:

[0033]

[0034] In the formula: λ is the combined heat transfer coefficient of the catalyst and carbon-containing gas, which is generally taken as 21~26 W / (m³). 2 ·K). ε is the combined emissivity of the catalyst and carbon-containing gas, typically taken as 0.9~0.95. σ is a constant, typically taken as 5.67×10 -8 W / (m 2 ·K 4 The temperature t5 of the catalytic reforming unit is controlled (generally 700-900℃, preferably 750-870℃, more preferably 800-840℃), and the temperature t6 of the catalyst regeneration unit is controlled (generally 600-800℃, preferably 630-750℃, more preferably 660-700℃). Based on experimental data, the above formula is simplified to:

[0035] q0=(45.6λ+662+ 3.14ρ×c) ×a×b / (Q1×d%×e%).

[0036] Furthermore, the number of unit cavities n can be determined by the amount of carbon-containing gas q1 (m³) to be processed. 3 / h), CO2 volume concentration in carbonaceous gas (d%), CO2 capture and cracking rate e%, reducing gas (e.g., CH4 or natural gas) flow rate q2 (m 3 The efficiency (f%) is determined by factors such as the reaction rate ( / h) and the synthesis efficiency (f%). To maintain the balance of effective catalysts in the catalytic reforming unit and the catalyst regeneration unit, the following generally apply:

[0037] q2×f%=1.06×q1×d%×e.

[0038] The number of unit cavities n≥2×([q1 / q0]+2), where “[ ]” indicates rounding down.

[0039] In this invention, the reduction and regeneration of the catalyst is an endothermic reaction, but the heat released by the CO2 catalytic reforming unit is insufficient. Therefore, an additional heating mechanism is needed in the catalyst regeneration unit. Generally, the heating mechanism can be any one of an electric heating wire, an electric heating plate, a hot air duct network, or an oxygen supply duct network. When hot air is used for heating in the catalyst regeneration unit, the hot air temperature t3 generated by the hot air furnace is generally in the range of 800~1000℃ (preferably 840~920℃), while the hot air volume (q3, m...)... 3 / h) and reducing gas (e.g., CH4 or natural gas) flow rate q2 (m 3 The heat exchange efficiency is related to factors such as the heat exchange rate ( / h) and the reducing gas inlet temperature t2 (°C). Assuming the heat exchange efficiency is 96%, then:

[0040]

[0041] Summarized as follows:

[0042]

[0043] Where: Cp2 is the isobaric specific heat capacity of reducing gas (kJ / (m³)) 3 ·K), Cp3 is the specific heat capacity of hot air at constant pressure (kJ / (m³)). 3 ·K), t2 is the temperature of the reducing gas (°C), and t7 is the temperature of the hot air after heat exchange (°C).

[0044] Furthermore, the switching interval between the catalytic reforming unit and the catalyst regeneration unit is related to q1, reactor size, catalyst adsorption capacity, etc. Assuming the adsorption saturation coefficient is 0.8, the switching time t0 is:

[0045] t0=[(n / 2×a×b×c×ρ)×0.8k]÷(1.964×q1×d%×e%).

[0046] Where: k is the catalyst adsorption capacity kg(CO2) / kg.

[0047] In this invention, when pure oxygen is used instead of a hot blast furnace for supplemental heating, the temperature of the catalyst regeneration unit is controlled by adjusting the amount of pure oxygen introduced. Since the reaction temperature of the catalyst regeneration unit is approximately 680°C, the addition of a small amount of oxygen will result in the following reaction with the reducing gas (CH4):

[0048] O2 + 2CH4 → 2CO + 4H2 + Q3.

[0049] The amount of oxygen added, q5, is:

[0050] .

[0051] Summarized as follows:

[0052] q5=[44.64×q2×f%×Q2-1000×m×Cp4×(t5-t6)-q2×Cp2×(t2-t6)] / [Cp5×(t8-t6)+44.64×Q3].

[0053] In this invention, the reforming catalyst is calcium oxide and / or a lanthanum-manganese-iron-nickel composite oxide, preferably a lanthanum-manganese-iron-nickel composite oxide. The structural formula of the lanthanum-manganese-iron-nickel composite oxide is LaMn. x Fe y Ni z O3, where: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5. Preferably, 0.1≤x≤0.3, 0.3≤y≤0.8, 0.1≤z≤0.4. More preferably, 0.15≤x≤0.25, 0.45≤y≤0.65, 0.2≤z≤0.3. x+y+z=1.

[0054] The reaction that occurs in the catalytic reforming unit is: CO2 + MeO x-1 →MeO x +CO+Q1 (approximately 79~68 kJ / mol).

[0055] The reaction that occurs in the catalyst regeneration unit is: MeO x +CH4→MeO x-1 +CO+2H2-Q2 (approximately 315~326 kJ / mol).

[0056] Among them: MeO x-1 and MeO x These represent the reduced catalyst (after regeneration) and the oxidized catalyst (after deactivation), respectively.

[0057] In this invention, the lanthanum manganese iron-nickel composite oxide (LaMn) x Fe y Ni z O3 is prepared by the following method:

[0058] a) First, add one or more of the following salts to water to obtain a mixed salt solution: lanthanum salt (lanthanum nitrate, lanthanum chloride, lanthanum bromide, lanthanum sulfate, lanthanum acetate), manganese salt (manganese nitrate, manganese chloride, manganese bromide, manganese sulfate, manganese acetate), ferric salt (ferric nitrate, ferric chloride, ferric bromide, ferric sulfate, ferric acetate, ferrous nitrate, ferrous chloride, ferrous bromide, ferrous sulfate, ferrous acetate), and nickel salt (nickel nitrate, nickel chloride, nickel bromide, nickel sulfate, nickel acetate). Then, add a complexing agent (citric acid) to the mixed salt solution and mix well to obtain a precursor solution. In the precursor solution, the molar ratio of lanthanum, manganese, iron, and nickel ions is 1:0.05~0.4:0.1~0.95:0~0.5, preferably 1:0.1~0.3:0.3~0.8:0.1~0.4, and more preferably 1:0.15~0.25:0.45~0.65:0.2~0.3. The amount of complexing agent added is 1~4 times the total molar amount of all metal ions, preferably 1.2~3 times, and more preferably 1.5~2 times. The total mass concentration of lanthanum salt, manganese salt, iron salt, and nickel salt is not less than 20%, preferably not less than 30%.

[0059] b) First, heat and stir the precursor solution until gelation occurs. For example, heat the precursor solution to 60-100°C (preferably 70-90°C) and maintain a stirring rate of 200-600 rpm (preferably 300-500 rpm). Then, subject the resulting gel to drying (drying at 100-150°C (preferably 110-140°C) for 5-24 h (preferably 8-20 h)) and calcination (first calcining at 200-500°C (preferably 300-400°C) for 1-8 h (preferably 2-6 h), then calcining at a heating rate of 2-10°C / min to 100-1400°C (preferably 1100-1300°C) for 1-8 h (preferably 2-6 h)) to obtain the target composite oxide (i.e., catalyst material).

[0060] This invention utilizes solid composite oxides as carriers of oxygen atoms and heat, cleverly circumventing the limitations of thermodynamic equilibrium by decomposing the traditional reaction into alternating sub-reactions in two independent reactors, thus achieving staged energy conversion and in-situ separation of products. Its basic principle is: first, a reducing gas (such as H2, CH4, or syngas) is used to reduce the catalyst (reduction reaction formula: MeO). x +CH4→MeO x-1 +2H2+CO), producing products such as H2O or CO2 and obtaining a reduced catalyst (MeO). x-1 Subsequently, a reduced catalyst was used to catalytically crack and reform CO2 in the carbon-containing gas (the cracking reaction is: CO2 + MeO). x-1 →MeO xThe catalyst selectively reduces CO2 to CO by drawing oxygen from the lattice of the CO2 molecule, while the reduced catalyst is oxidized and enters the next cycle. Essentially, this process utilizes the "absorption" and "expulsion" of lattice oxygen by the catalyst to activate CO2 molecules and remove oxygen atoms.

[0061] In this invention, existing CO2 reduction catalysts are insufficient to meet the requirements of continuous cracking and reforming of carbon-containing gases in terms of activity and stability. Therefore, this invention addresses this issue by carefully designing the chemical composition and crystal structure of a lanthanum-manganese-iron-nickel composite oxide, namely LaMn... x Fe y Ni z O3, in particular, by introducing three transition metal elements, manganese (Mn), iron (Fe) and nickel (Ni), at the B site, aims to optimize the electronic structure, oxygen vacancy concentration and redox performance of the catalyst by utilizing the synergistic effect of each metal element. Through this multi-element synergistic design strategy, the catalyst can exhibit excellent performance in the reaction of CO2 catalytic conversion to CO, thereby overcoming the technical bottleneck of existing catalysts.

[0062] In this invention, lanthanum is used as LaMn. x Fe y Ni z Lanthanum (La), the A-site cation in O3, plays a crucial role in the catalyst of this invention, mainly in the following aspects: First, the presence of lanthanum is a core element in maintaining the stability of the perovskite crystal structure. The general formula of the perovskite structure is ABO3, where the A-site is usually a rare earth or alkaline earth metal ion with a large radius. 3+ Lanthanum possesses a suitable ionic radius and a stable +3 oxidation state, enabling it to effectively occupy the A-site and form a stable cubic or orthorhombic crystal structure framework with oxygen ions. This stable crystal structure is the basis for maintaining the structural integrity of the catalyst during subsequent high-temperature calcination and under catalytic reaction conditions (especially potentially high-temperature environments), preventing the loss of active sites due to structural collapse or phase transition. Secondly, as an A-site ion, lanthanum's electronegativity significantly influences the electronic structure and oxygen species behavior of the entire perovskite oxide. The high electronegativity of lanthanum ions strongly attracts the electron cloud of oxygen ions, thus affecting the bonding strength between B-site transition metal ions and oxygen ions. This influence can regulate the formation energy and mobility of oxygen vacancies in the catalyst (oxygen vacancies are key active sites in CO2 reduction reactions, serving as centers for CO2 molecule adsorption and dissociation). The presence of lanthanum helps to form an appropriate amount of stable oxygen vacancies in the perovskite structure, especially when different valence states of transition metals (such as Mn, Fe, Ni) are introduced at the B-site. The stabilizing effect of lanthanum can promote valence state cycling among these transition metal ions (e.g., Fe). 3+ / Fe 2+Ni 3+ / Ni 2+ Mn 4+ / Mn 3+ / Mn 2+ This leads to the generation of more active oxygen vacancies through redox reactions. Furthermore, the introduction of lanthanum helps improve the catalyst's thermal stability and anti-sintering ability. In high-temperature calcination preparation processes and potential high-temperature catalytic reactions, lanthanum oxides (such as La₂O₃) possess high melting points and chemical stability, which can inhibit catalyst particle agglomeration and sintering of B-site active metal components, thereby maintaining the catalyst's large specific surface area and abundant active sites, ensuring its catalytic performance stability during long-term operation. Simultaneously, the presence of lanthanum ions may also affect the catalytic activity of B-site transition metal ions through steric and electronic effects; the large ionic radius of lanthanum allows for the adjustment of the lattice parameters of the perovskite structure, providing a suitable coordination environment and crystal field strength for B-site metal ions, which may optimize the adsorption configuration and activation barrier of CO₂ molecules by the B-site metal; moreover, the interaction between lanthanum and the B-site metal may also promote electron transfer between metal-oxygen bonds, accelerating the kinetics of redox reactions. In summary, lanthanum is not only a framework element for constructing and stabilizing the perovskite structure in the catalyst of this invention, but also lays an important foundation for the catalyst to exhibit excellent performance in the CO2 catalytic production of CO through its comprehensive regulation of crystal structure, electronic properties, oxygen vacancy behavior and thermal stability.

[0063] In this invention, iron, as the main constituent element at the B-site, helps stabilize the perovskite structure and provides certain catalytically active sites, playing a core role in the catalytic performance of the catalyst. Specifically, iron exhibits a wide range of valence states (e.g., Fe). 3+ Fe 2+ Fe can even appear under specific conditions. 4+ This variability in valence state is key to its participation in redox reactions. In the process of CO2 reduction to CO, Fe ions can act as active centers, participating through cyclical changes in their valence state (Fe...). 3+ +e- Fe 2+ Fe ions transfer electrons, promoting the adsorption, activation, and electron transfer processes of CO2 molecules. In other words, CO2 molecules can adsorb onto Fe ion sites, and Fe... 2+Fe can donate electrons to CO2 molecules, enabling their reduction to CO. Simultaneously, the introduction of Fe helps regulate the lattice oxygen activity and oxygen vacancy concentration in the perovskite structure. The moderate bond energy between Fe and oxygen ions allows for a certain degree of fluidity of lattice oxygen during the reaction, which is crucial for CO2 activation and oxygen species migration. It should be noted that an appropriate Fe content can create more oxygen vacancies on the catalyst surface and in the bulk phase. These vacancies not only serve as adsorption sites for CO2 molecules but also lower the activation energy barrier required for CO2 decomposition, thereby improving the catalytic activity. However, excessive Fe content may lead to overcrowding of metal ions in the perovskite structure, affecting lattice stability and the uniform distribution of oxygen vacancies, and may even induce the formation of impurity phases, thus reducing catalytic performance. Conversely, insufficient Fe content cannot provide enough active sites and is unlikely to effectively synergize with other B-site elements such as Mn and Ni, resulting in poor overall catalytic activity and selectivity. This invention achieves highly efficient catalysis of the CO2 reduction reaction by precisely controlling the proportion of Fe at the B site, ensuring that Fe not only provides sufficient catalytic sites as the main active component but also synergistically optimizes the electronic structure and oxygen vacancy characteristics of the catalyst with Mn and Ni elements. Therefore, in the LaMn catalyst of this invention... x Fe y Ni z In the O3 system, precisely controlling the proportion of iron to ensure its synergistic effect with manganese and nickel is crucial for achieving high catalyst performance. Furthermore, iron exhibits good stability within the perovskite structure, forming stable solid solutions with lanthanum and other B-site metals. This helps maintain the structural integrity of the catalyst under high-temperature reaction conditions, reducing the loss and sintering of active components.

[0064] In this invention, the addition of manganese significantly improves the cyclic stability and resistance to carbon deposition of the catalyst during CO2 cracking. Firstly, manganese (Mn) also exhibits a wide range of valence states (Mn... 2+ Mn 3+ Mn 4+ This multi-valence characteristic makes it an excellent electron shuttle in catalysts, enabling it to participate efficiently in electron transfer during redox reactions; that is, in the CO2 reduction reaction, Mn can participate through rapid valence state cycling (e.g., Mn...). 4+ +e - Mn 3+ Mn 3+ +e - Mn 2+Mn promotes electron transfer, providing a continuous electron supply for the activation of CO2 molecules, thereby accelerating reaction kinetics. Furthermore, the introduction of Mn helps stabilize the oxygen ion framework in the perovskite structure. This is because the strong bonding between Mn ions and oxygen ions enhances the rigidity of the crystal structure, suppressing lattice distortion and oxygen ion loss that may occur under high-temperature reaction conditions or during long-term operation, thus improving the catalyst's structural stability and anti-aging performance. Simultaneously, Mn can synergistically interact with Fe and Ni elements to jointly regulate the oxygen vacancy concentration and distribution of the catalyst. This is because the specific valence state and ionic radius of Mn can influence the local electronic environment of surrounding Fe and Ni ions, optimizing the geometry and electronic state of active sites, thus achieving an optimal balance between CO2 adsorption, activation, and CO desorption processes. Research has shown that controlling the Mn ratio within the range of 0.05 ≤ x ≤ 0.4 (preferably 0.1 ≤ x ≤ 0.3, more preferably 0.15 ≤ x ≤ 0.25) fully leverages its advantages in redox cycles, structural stability, and synergistic effects with other metal elements. This ensures the catalyst exhibits excellent catalytic activity and stability under medium- and low-temperature conditions, avoiding excessive activity of lattice oxygen due to excessive Mn content, which could trigger side reactions or excessive oxidation of the catalyst surface. It also prevents insufficient Mn content from effectively participating in electron transfer and structural stability, thus guaranteeing the optimal effect of Mn in improving catalyst cycle stability and anti-carbon deposition performance. In other words, an appropriate Mn content can form a good multi-metal synergistic system with Fe and Ni at the B-site, effectively inhibiting the deposition of carbon species on the catalyst surface during the reaction. This is because the presence of Mn promotes the activation and migration of adsorbed oxygen species on the surface, promptly oxidizing carbon precursors to CO or CO2 for removal, thereby maintaining the cleanliness of the catalyst surface active sites and extending the catalyst's lifespan. Meanwhile, the introduction of Mn can also regulate the acid-base properties of the catalyst, optimize the adsorption strength of CO2 molecules, avoid the difficulty of product desorption caused by excessive adsorption or the insufficient activation caused by excessively weak adsorption, and further improve the selectivity and stability of the catalytic reaction.

[0065] In this invention, nickel, as another important dopant element at the B site, can regulate the electronic properties of the catalyst and enhance the synergistic effect of the active site, thereby increasing the lattice oxygen release rate of the catalyst and further improving the CO2 conversion rate. Nickel (Ni) also has a variable valence state (Ni... 2+ Ni 3+The introduction of Ni enables strong electronic interactions with elements such as Fe and Mn, further optimizing the electronic conductivity of the perovskite structure. These interactions further promote charge transfer on the catalyst surface, accelerating electron transfer of CO2 molecules at active sites, thereby improving CO2 activation efficiency. Furthermore, the introduction of Ni helps increase the oxygen vacancy concentration on the catalyst surface. Because Ni ions have relatively weaker bonds with surrounding oxygen ions, they more easily lose oxygen atoms under reaction conditions to form oxygen vacancies. These newly created oxygen vacancies, combined with those generated by Fe and Mn sites, form more active centers, enhancing CO2 adsorption and activation capabilities. Simultaneously, the presence of Ni also improves the catalyst's selectivity for CO products. Studies show that Ni sites exhibit moderate CO adsorption energy, promoting CO2 reduction to CO without causing excessive hydrogenation or deep reduction of CO to other byproducts, thus ensuring high CO selectivity while improving CO2 conversion. Studies have found that when the amount of Ni doping is controlled to be ≤0.5 (preferably 0.1≤z≤0.4, more preferably 0.2≤z≤0.3), it can form an optimal ratio with Fe and Mn elements at the B site. Utilizing the synergistic effect of these three elements, the overall catalytic performance of the catalyst can be significantly improved. Specifically, appropriate Ni doping can optimize the surface electronic state of the catalyst, lower the activation energy barrier of CO2 molecules, promote the adsorption and dissociation of CO2 at active sites, and accelerate the migration and release of lattice oxygen, providing sufficient oxygen vacancies and active oxygen species for the CO2 reduction reaction, thereby significantly improving the CO2 conversion rate and CO generation rate. It should be noted that excessive Ni doping may lead to an imbalance in the distribution of metal ions in the perovskite structure, causing lattice distortion or impurity phase formation, which in turn damages structural stability and the uniformity of active sites. Conversely, insufficient Ni doping makes it difficult to fully utilize its regulatory effect on electronic properties and its synergistic effect with Fe and Mn, resulting in insufficient improvement in lattice oxygen release rate and CO2 conversion rate. Therefore, precisely controlling the Ni doping ratio to form a synergistic and complementary active center system with Fe and Mn at the B site is one of the key factors in achieving high activity, high selectivity and high stability of the catalyst.

[0066] In this invention, citric acid is used as a complexing agent (or chelating agent) because it forms stable complexes with metal ions (lanthanum ions, manganese ions, iron ions, and nickel ions), preventing premature precipitation or segregation of metal ions in subsequent processes. This ensures that the metal elements can be uniformly mixed at the molecular level, which is beneficial for the formation of uniformly structured LaMn during subsequent calcination. x Fe y Ni zO3 perovskite oxide; meanwhile, citric acid, as an organic carbon source, will burn and decompose during calcination, and the generated gas can promote the formation of a porous structure in the catalyst, thereby increasing the specific surface area of ​​the catalyst and helping to improve the catalytic activity of the catalyst.

[0067] In this invention, a two-stage calcination process is employed to achieve phased formation and optimization of the catalyst structure. The first stage of calcination is preferably carried out at a low temperature of 300-400°C. Its main purpose is to remove moisture, volatile organic compounds, and decomposing complexing agents (such as citric acid) from the gel precursor, avoiding catalyst structural breakage or defects caused by the rapid release of large amounts of gas during direct high-temperature calcination. Simultaneously, this stage allows the metal ions to undergo preliminary reactions, forming an amorphous or low-crystallinity precursor. The second stage of calcination involves raising the temperature to 1100-1300°C, a crucial stage for perovskite crystal phase formation. At this high temperature, metal ions gain sufficient energy for diffusion and rearrangement, gradually forming LaMn with a complete cubic or orthorhombic crystal structure. x Fe y Ni z O3, a perovskite oxide, requires a higher calcination temperature to improve crystallinity and structural order, enhancing the catalyst's thermal stability and mechanical strength. Simultaneously, appropriate high temperatures promote the ordered arrangement of lattice oxygen and the formation and regulation of oxygen vacancies, ensuring the catalyst exhibits excellent redox performance. This two-step calcination process avoids the structural defects and compositional inhomogeneities that may result from a single high-temperature calcination step. Furthermore, precise control of temperature and time at each stage allows for accurate regulation of the catalyst's crystal structure, specific surface area, pore structure, and active site distribution, ensuring the final catalyst possesses superior catalytic activity and stability.

[0068] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0069] 1. The integrated CO2 in-situ reforming system of this invention integrates CO2 capture and catalytic reforming processes within the same shell cavity. It utilizes a reforming catalyst to simultaneously achieve CO2 adsorption capture and catalytic reforming conversion. Through alternating operations or spatial partitioning, it achieves continuous and stable operation of both capture and conversion processes. Compared to traditional segmented processes, this system eliminates intermediate steps such as CO2 desorption, purification, and compression transfer, significantly reducing carbon and energy losses in these intermediate processes. It features high equipment integration, a small footprint, lower investment and operating costs, and a higher CO2 capture and conversion rate. It can stably achieve continuous "capture-conversion-regeneration" cycle operation, significantly improving carbon resource utilization. It is suitable for the CO2 resource utilization needs of various continuously emitted carbon-containing gases such as industrial flue gas and exhaust gas, and can be widely applied in carbon reduction projects in multiple industries such as power, chemical, and metallurgy.

[0070] 2: This invention effectively regulates the crystal structure, electronic properties, and oxygen vacancy characteristics of the catalyst through the synergistic effect of metal elements such as lanthanum, manganese, iron, and nickel. Compared with single or binary metal oxygen carriers, it can achieve higher CO2 conversion rate and CO selectivity under medium and low temperature conditions, significantly reducing the energy consumption of CO2 cracking reaction. At the same time, the catalyst has excellent cycle stability and anti-carbon deposition performance, and can operate stably for a long time, which can significantly reduce process operation and maintenance costs. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of the structure of the system of the present invention when it is divided into a reforming chamber and a synthesis chamber.

[0072] Figure 2 This is a schematic diagram of the structure in which the reforming chamber and the synthesis chamber of the present invention are connected by a circular tube.

[0073] Figure 3 This is a schematic diagram showing the distribution of the material cone at the bottom of the synthesis chamber in this invention.

[0074] Figure 4 This is a schematic diagram of the structure of the system of the present invention when it is divided into multiple unit cavities.

[0075] Figure 5 This is a schematic diagram of the structure of the synthesis chamber of the present invention when the heating mechanism is an oxygen supply network.

[0076] Figure 6 This is a schematic diagram of the structure of the heating mechanism of the unit cavity of the present invention when it is an oxygen supply network.

[0077] Reference numerals: 1: Shell; 2: Inner cavity; 201: Reforming chamber; 202: Synthesis chamber; 203: Unit chamber; 2031: Unit intake branch pipe; 2032: Unit exhaust branch pipe; 2033: First intake main pipe; 2034: First exhaust main pipe; 2035: Second intake main pipe; 2036: Second exhaust main pipe; 2037: Valve pipe; 204: Carbon-containing gas input pipe; 205: Reformed gas output pipe; 2 06: Reducing gas input pipeline; 207: Synthesis gas output pipeline; 208: Heating mechanism; 2081: Air inlet pipe; 2082: Heat exchanger tube array; 2083: Exhaust pipe; 2084: Hot blast furnace; 2085: Main oxygen supply pipeline; 2086: Oxygen supply branch pipe; 209: Reforming catalyst particles; 210: Reforming catalyst bed; 211: Flat channel; 212: Distribution cone; 213: Catalyst circulation conveying device. Detailed Implementation

[0078] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0079] An integrated CO2 in-situ reforming system, comprising a housing 1 and an inner cavity 2. The inner cavity 2 is divided from top to bottom into a reforming cavity 201 and a synthesis cavity 202, or the inner cavity 2 is divided horizontally into multiple (at least two) unit cavities 203.

[0080] The reforming chamber 201 and the synthesis chamber 202 are connected. A carbon-containing gas input pipe 204 and a reformed gas output pipe 205 are connected to the reforming chamber 201. A reducing gas input pipe 206 and a synthesis gas output pipe 207 are connected to the synthesis chamber 202. A heating mechanism 208 is installed inside the synthesis chamber 202. Both the reforming chamber 201 and the synthesis chamber 202 are filled with reforming catalyst particles 209.

[0081] The multiple unit cavities 203 are not interconnected, and each unit cavity 203 is independently equipped with a heating mechanism 208 and a reforming catalyst bed 210. A carbon-containing gas input pipe 204 and a reforming gas output pipe 205 are connected to at least one unit cavity 203. A reducing gas input pipe 206 and a synthesis gas output pipe 207 are connected to at least one unit cavity 203.

[0082] Preferably, the reforming chamber 201 and the synthesis chamber 202 are connected by multiple flat channels 211 that are wide at the ends and narrow in the middle. Alternatively, the reforming chamber 201 and the synthesis chamber 202 can be connected by multiple evenly distributed round or square tubes.

[0083] Preferably, a uniform discharge mechanism is provided at the bottom discharge port of the synthesis chamber 202. This uniform discharge mechanism consists of multiple evenly spaced distribution cones 212, each wider at the bottom than the top. The inclination angle of the cone surface of each distribution cone 212 is greater than the angle of repose of the reforming catalyst particles 209. Preferably, the inclination angle of the cone surface of each distribution cone 212 is 2-10° greater than the angle of repose of the reforming catalyst particles 209. Preferably, each distribution cone 212 is a square pyramid, and the distance between distribution cones 212 and between each distribution cone 212 and the inner wall of the synthesis chamber 202 is 20-80 mm. The bottom side length of each distribution cone 212 is 100-800 mm.

[0084] Preferably, the bottom discharge port of the synthesis chamber 202 is connected to the top feed port of the reforming chamber 201 via a catalyst circulation conveying device 213. The reforming catalyst particles 209 circulate between the reforming chamber 201 and the synthesis chamber 202 via the catalyst circulation conveying device 213. Preferably, a material temperature sensor (thermocouple) and a material flow regulating valve (rotary valve) are provided on the catalyst circulation conveying device 213.

[0085] Preferably, the heating mechanism 208 is an electric heating wire, an electric heating plate, a hot air duct network, or an oxygen supply duct network.

[0086] Preferably, gas temperature detectors (thermocouples) and gas flow regulating valves (pneumatic regulating valves) are independently installed on carbon gas input pipe 204, reforming gas output pipe 205, reducing gas input pipe 206, and synthesis gas output pipe 207.

[0087] Preferably, the heating mechanism 208 is a hot air duct network, which includes an air inlet pipe 2081, a heat exchange tube array 2082, and an exhaust pipe 2083 connected in series. The heat exchange tube array 2082 is disposed inside the synthesis chamber 202 or is independently disposed in each unit chamber 203. The air inlet pipe 2081 and the exhaust pipe 2083 are disposed outside the housing 1, and the air inlet pipe 2081 is connected to the hot air furnace 2084. Preferably, the heat exchange tube array 2082 in each unit chamber 203 is connected to the air inlet pipe 2081 and the exhaust pipe 2083 through independent air inlet branch pipes and exhaust branch pipes, respectively.

[0088] Preferably, the heating mechanism 208 is an oxygen supply network, which includes a main oxygen supply pipe 2085 and several oxygen supply branch pipes 2086. The main oxygen supply pipe 2085 is connected to the synthesis chamber 202 through the several oxygen supply branch pipes 2086, or the main oxygen supply pipe 2085 is connected to each unit chamber 203 through the several oxygen supply branch pipes 2086 respectively. Each of the main oxygen supply pipe 2085 and the several oxygen supply branch pipes 2086 is independently equipped with a throttling valve.

[0089] Preferably, each unit cavity 203 is provided with a unit intake branch pipe 2031 and a unit exhaust branch pipe 2032. All unit cavities 203 are arranged horizontally along the inner cavity 2, wherein: the unit intake branch pipes 2031 of all odd-numbered unit cavities 203 are connected to the first main intake pipe 2033, and the unit exhaust branch pipes 2032 of all odd-numbered unit cavities 203 are connected to the first main exhaust pipe 2034. The unit intake branch pipes 2031 of all even-numbered unit cavities 203 are connected to the second main intake pipe 2035, and the unit exhaust branch pipes 2032 of all even-numbered unit cavities 203 are connected to the second main exhaust pipe 2036. Both ends of the first main intake pipe 2033 and the second main intake pipe 2035 are connected to the carbon-containing gas input pipe 204 and the reducing gas input pipe 206 respectively via independent valve pipes 2037. Both ends of the first exhaust pipe 2034 and the second exhaust pipe 2036 are connected to the reforming gas output pipe 205 and the synthesis gas output pipe 207 respectively through independent gas valve pipes 2037.

[0090] Preferably, the reforming catalyst in the reforming catalyst particles 209 and the reforming catalyst bed 210 is calcium oxide and / or lanthanum manganese iron nickel composite oxide.

[0091] Preferably, the structural formula of the lanthanum manganese iron-nickel composite oxide is LaMn. x Fe y Ni z O3, where: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5. Preferably, 0.1≤x≤0.3, 0.3≤y≤0.8, 0.1≤z≤0.4. More preferably, 0.15≤x≤0.25, 0.45≤y≤0.65, 0.2≤z≤0.3. x+y+z=1.

[0092] Example 1

[0093] like Figure 1-3 As shown in Figure 5, an integrated CO2 in-situ reforming system includes a housing 1 and an inner cavity 2. The inner cavity 2 is divided from top to bottom into a reforming cavity 201 and a synthesis cavity 202.

[0094] The reforming chamber 201 and the synthesis chamber 202 are connected. A carbon-containing gas input pipe 204 and a reformed gas output pipe 205 are connected to the reforming chamber 201. A reducing gas input pipe 206 and a synthesis gas output pipe 207 are connected to the synthesis chamber 202. A heating mechanism 208 is installed inside the synthesis chamber 202. Both the reforming chamber 201 and the synthesis chamber 202 are filled with reforming catalyst particles 209.

[0095] Example 2

[0096] The embodiment 1 is repeated, except that the reforming chamber 201 and the synthesis chamber 202 are connected by multiple flat channels 211 that are wide at the ends and narrow in the middle.

[0097] Example 3

[0098] Repeat Example 1, except that the reforming chamber 201 and the synthesis chamber 202 are connected by multiple evenly distributed circular tubes.

[0099] Example 4

[0100] Example 2 is repeated, except that a uniform discharge mechanism is provided at the bottom discharge port of the synthesis chamber 202. The uniform discharge mechanism is composed of multiple distribution cones 212 that are pointed at the top and wide at the bottom, evenly distributed. The inclination angle of the cone surface of the distribution cone 212 is greater than the packing angle of the reforming catalyst particles 209.

[0101] Example 5

[0102] Example 4 was repeated, except that the tilt angle of the cone surface of the distribution cone 212 was 5° larger than the packing angle of the reforming catalyst particles 209.

[0103] Example 6

[0104] Example 5 is repeated, except that the distributing cone 212 is a square pyramid, and the distance between distributing cones 212 and between distributing cone 212 and the inner wall of the synthesis chamber 202 is 60mm. The bottom side length of the distributing cone 212 is 600mm.

[0105] Example 7

[0106] Example 6 is repeated, except that the bottom discharge port of the synthesis chamber 202 is connected to the top feed port of the reforming chamber 201 through the catalyst circulation conveying device 213. The reforming catalyst particles 209 flow and circulate between the reforming chamber 201 and the synthesis chamber 202 through the catalyst circulation conveying device 213.

[0107] Example 8

[0108] Repeat Example 7, except that a material temperature sensor (thermocouple) and a material flow regulating valve (star-shaped discharge valve) are installed on the catalyst circulation conveying device 213.

[0109] Example 9

[0110] Example 7 is repeated, except that a gas temperature sensor (thermocouple) and a gas flow regulating valve (pneumatic regulating valve) are independently installed on the carbon gas input pipeline 204, the reforming gas output pipeline 205, the reducing gas input pipeline 206, and the synthesis gas output pipeline 207.

[0111] Example 10

[0112] The embodiment 9 is repeated, except that the heating mechanism 208 is a hot air duct network, which includes an air inlet pipe 2081, a heat exchange tube array 2082, and an exhaust pipe 2083 connected in series. The heat exchange tube array 2082 is disposed inside the synthesis chamber 202 or is independently disposed in each unit chamber 203. The air inlet pipe 2081 and the exhaust pipe 2083 are disposed outside the housing 1, and the air inlet pipe 2081 is connected to the hot air furnace 2084.

[0113] Example 11

[0114] Example 10 is repeated, except that the heat exchange tube array 2082 in each unit cavity 203 is connected to the air inlet pipe 2081 and the air outlet pipe 2083 respectively through independent air inlet branch pipes and air outlet branch pipes.

[0115] Example 12

[0116] The embodiment 9 is repeated, except that the heating mechanism 208 is an oxygen supply network, which includes a main oxygen supply pipeline 2085 and several oxygen supply branch pipes 2086. The main oxygen supply pipeline 2085 is connected to the synthesis chamber 202 through several oxygen supply branch pipes 2086.

[0117] Example 13

[0118] Example 12 was repeated, except that the reforming catalyst in the reforming catalyst particles 209 was calcium oxide.

[0119] Example 14

[0120] Example 13 was repeated, except that the reforming catalyst in the reforming catalyst particles 209 was a lanthanum manganese iron nickel composite oxide.

[0121] Example 15

[0122] Example 14 is repeated, except that the structural formula of the lanthanum manganese iron-nickel composite oxide is LaMn. x Fe y Ni z O3, where: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5. x+y+z=1.

[0123] Example 16

[0124] Repeat Example 15, except that 0.1≤x≤0.3, 0.3≤y≤0.8, and 0.1≤z≤0.4.

[0125] Example 17

[0126] Repeat Example 16, except that 0.15≤x≤0.25, 0.45≤y≤0.65, and 0.2≤z≤0.3.

[0127] The usage process of the integrated CO2 in-situ reforming system, which includes reforming chamber 201 and synthesis chamber 202, is as follows:

[0128] (1) When the reforming catalyst in the reforming catalyst particles 209 is calcium oxide, carbon-containing flue gas is introduced into the reforming chamber 201 through the carbon-containing gas input pipe 204 and flows from bottom to top, contacting the reforming catalyst particles 209 flowing from top to bottom in a countercurrent manner. CO2 in the carbon-containing flue gas is adsorbed by calcium oxide to generate calcium carbonate. The flue gas, from which CO2 has been removed, is discharged through the reforming gas output pipe 205. The generated calcium carbonate enters the synthesis chamber 202 through the flat channel 211. At this time, reducing gas (e.g., calcium carbonate) is introduced into the synthesis chamber 202 through the reducing gas input pipe 206. Methane flows upwards and reacts countercurrently with calcium carbonate. During this process, hot air is obtained through hot blast furnace 2084 and further sent into heat exchange tube array 2082 through air inlet pipe 2081. The hot air radiates heat to the outside through heat exchange tube array 2082 to promote the reduction of calcium carbonate to calcium oxide by reducing gas and generate synthesis gas (or oxygen is directly input into synthesis chamber 202 through main oxygen supply pipe 2085 and several oxygen supply branch pipes 2086, and heat is released through the reaction of oxygen with reducing gas). The hot air after heat exchange is discharged through exhaust pipe 2083. Synthesis gas is discharged through synthesis gas output pipe 207. The obtained calcium oxide is transported back to reforming chamber 201 for recycling through catalyst circulation conveying device 213, and this cycle continues.

[0129] (2) When the reforming catalyst in the reforming catalyst particle 209 is a lanthanum manganese iron nickel composite oxide, the lanthanum manganese iron nickel composite oxide first passes through the reforming chamber 201 and the flat channel 211 and then enters the synthesis chamber 202 for reduction treatment (at this time, no carbon-containing flue gas is introduced into the reforming chamber 201). The reducing gas (e.g., methane) is introduced into the synthesis chamber 202 through the reducing gas input pipe 206 and flows from bottom to top to react countercurrently with the lanthanum manganese iron nickel composite oxide. During this process, hot air is obtained through the hot air furnace 2084 and further sent into the heat exchange tube array 2082 through the air inlet pipe 2081. The hot air radiates heat to the outside through the heat exchange tube array 2082 to promote the reducing gas to reduce the lanthanum manganese iron nickel composite oxide to the reduced state and generate synthesis gas (or oxygen is directly introduced into the synthesis chamber 202 through the main oxygen supply pipe 2085 and several oxygen supply branch pipes 2086, and heat is released through the reaction of oxygen with reducing gas). The hot air after heat exchange is discharged through the exhaust pipe 2083. The resulting syngas is discharged through syngas output pipe 207. The resulting reduced lanthanum manganese iron nickel composite oxide is transported back to the reforming chamber 201 through catalyst circulation conveying device 213. At this time, carbon-containing flue gas can be introduced into the reforming chamber 201 through carbon-containing gas input pipe 204 and flows from bottom to top, contacting the reforming catalyst particles 209 flowing from top to bottom in a countercurrent manner. CO2 in the carbon-containing flue gas is adsorbed and cracked by the reduced lanthanum manganese iron nickel composite oxide to generate CO and lanthanum manganese iron nickel composite oxide. The reformed flue gas with CO2 removed is discharged through reformed gas output pipe 205. The generated lanthanum manganese iron nickel composite oxide is introduced into the synthesis chamber 202 through flat channel 211 for reduction treatment, and the cycle continues.

[0130] Example 18

[0131] like Figure 4 , 6 As shown, an integrated CO2 in-situ reforming system includes a housing 1 and an inner cavity 2. The inner cavity 2 is horizontally divided into multiple unit cavities 203.

[0132] The multiple unit cavities 203 are not interconnected, and each unit cavity 203 is independently equipped with a heating mechanism 208 and a reforming catalyst bed 210. A carbon-containing gas input pipe 204 and a reforming gas output pipe 205 are connected to at least one unit cavity 203. A reducing gas input pipe 206 and a synthesis gas output pipe 207 are connected to at least one unit cavity 203.

[0133] Example 19

[0134] The embodiment 18 is repeated, except that each unit cavity 203 is provided with a unit intake branch pipe 2031 and a unit exhaust branch pipe 2032. All unit cavities 203 are arranged horizontally along the inner cavity 2, wherein: the unit intake branch pipes 2031 of all odd-numbered unit cavities 203 are connected to the first intake main pipe 2033, and the unit exhaust branch pipes 2032 of all odd-numbered unit cavities 203 are connected to the first exhaust main pipe 2034. The unit intake branch pipes 2031 of all even-numbered unit cavities 203 are connected to the second intake main pipe 2035, and the unit exhaust branch pipes 2032 of all even-numbered unit cavities 203 are connected to the second exhaust main pipe 2036. Both ends of the first intake main pipe 2033 and the second intake main pipe 2035 are connected to the carbon-containing gas input pipe 204 and the reducing gas input pipe 206 respectively via independent valve pipes 2037. Both ends of the first exhaust pipe 2034 and the second exhaust pipe 2036 are connected to the reforming gas output pipe 205 and the synthesis gas output pipe 207 respectively through independent gas valve pipes 2037.

[0135] Example 20

[0136] Example 19 is repeated, except that gas temperature detectors (thermocouples) and gas flow regulating valves (pneumatic regulating valves) are independently installed on carbon gas input pipe 204, reforming gas output pipe 205, reducing gas input pipe 206, and synthesis gas output pipe 207.

[0137] Example 21

[0138] The embodiment 20 is repeated, except that the heating mechanism 208 is a hot air duct network, which includes an air inlet pipe 2081, a heat exchange tube array 2082, and an exhaust pipe 2083 connected in series. The heat exchange tube array 2082 is disposed inside the synthesis chamber 202 or is independently disposed in each unit chamber 203. The air inlet pipe 2081 and the exhaust pipe 2083 are disposed outside the housing 1, and the air inlet pipe 2081 is connected to the hot air furnace 2084.

[0139] Example 22

[0140] The embodiment 21 is repeated, except that the heat exchange tube array 2082 in each unit cavity 203 is connected to the air inlet pipe 2081 and the air outlet pipe 2083 respectively through independent air inlet branch pipes and air outlet branch pipes.

[0141] Example 23

[0142] The embodiment 22 is repeated, except that the heating mechanism 208 is an oxygen supply network, which includes a main oxygen supply pipe 2085 and several oxygen supply branch pipes 2086. The main oxygen supply pipe 2085 is connected to the synthesis chamber 202 through the several oxygen supply branch pipes 2086, or the main oxygen supply pipe 2085 is connected to each unit chamber 203 through the several oxygen supply branch pipes 2086 respectively. Each of the main oxygen supply pipe 2085 and the several oxygen supply branch pipes 2086 is independently equipped with a throttling valve.

[0143] Example 24

[0144] Example 23 was repeated, except that the reforming catalyst in the reforming catalyst bed 210 was calcium oxide.

[0145] Example 25

[0146] Example 24 was repeated, except that the reforming catalyst in the reforming catalyst bed 210 was a lanthanum manganese iron nickel composite oxide.

[0147] Example 26

[0148] Example 25 is repeated, except that the structural formula of the lanthanum manganese iron-nickel composite oxide is LaMn. x Fe y Ni z O3, where: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5. x+y+z=1.

[0149] Example 27

[0150] Repeat Example 26, except that 0.1≤x≤0.3, 0.3≤y≤0.8, and 0.1≤z≤0.4.

[0151] Example 28

[0152] Repeat Example 27, except that 0.15≤x≤0.25, 0.45≤y≤0.65, and 0.2≤z≤0.3.

[0153] The usage process of the integrated CO2 in-situ reforming system, which includes multiple unit cavities 203, is as follows:

[0154] (1) When the reforming catalyst in the reforming catalyst bed 210 is calcium oxide, by adjusting the switch of the corresponding gas valve pipe 2037, the carbon-containing gas input pipe 204 inputs the carbon-containing flue gas through the first intake main pipe 2033 and the intake branch pipes 2031 of each unit into the odd-numbered unit cavity 203 and flows from bottom to top. The CO2 in the carbon-containing flue gas is adsorbed by the calcium oxide in the reforming catalyst bed 210 to generate calcium carbonate. The flue gas after removing CO2 is discharged through the exhaust branch pipes 2032 of each unit, the first exhaust main pipe 2034 and the reforming gas output pipe 205. When the calcium oxide in the reforming catalyst bed 210 is insufficient, the switch of the corresponding gas valve pipe 2037 is turned on, so that the carbon-containing gas input pipe 204 inputs the carbon-containing flue gas through the second intake main pipe 2035 and the intake branch pipes 2031 of each unit into the even-numbered unit cavity 203 to continue the reaction. The flue gas with CO2 removed is discharged through the exhaust branch pipes 2032 of each unit, the second exhaust main pipe 2036 and the reforming gas output pipe 205. Meanwhile, reducing gas (e.g., methane) is input into each odd-numbered unit cavity 203 through reducing gas input pipe 206, first main intake pipe 2033, and each unit intake branch pipe 2031, flowing upwards to reduce calcium carbonate to generate calcium oxide and syngas. During this process, hot air is obtained through hot air furnace 2084 and further sent into the heat exchange tube array 2082 of each odd-numbered unit cavity 203 through air inlet pipe 2081. The hot air radiates heat to the outside through the heat exchange tube array 2082 to promote the reduction of calcium carbonate to calcium oxide and generate syngas (or oxygen is directly input into the syngas cavity 202 through main oxygen supply pipe 2085 and several oxygen supply branch pipes 2086, releasing heat through the reaction of oxygen with reducing gas). The heat-exchanged hot air is discharged through exhaust pipe 2083. The generated syngas is discharged sequentially through the corresponding unit exhaust branch pipe 2032, first exhaust main pipe 2034, and syngas output pipe 207, in an alternating cycle.

[0155] (2) When the reforming catalyst in the reforming catalyst bed 210 is a lanthanum manganese iron nickel composite oxide, the first priority is to reduce the lanthanum manganese iron nickel composite oxide in each odd-numbered unit cavity 203 to a reduced state by reducing gas, and then treat the carbon-containing flue gas (simultaneously reduce the lanthanum manganese iron nickel composite oxide in the even-numbered unit cavity 203). The operation process is basically the same as the operation process of the calcium oxide catalyst mentioned above, and will not be repeated here.

[0156] Application Example 1

[0157] The system described in Example 28 is used to process blast furnace gas, with methane as the reducing gas. The various unit chambers 203 are sequentially numbered 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 in the horizontal direction. The reforming catalysts in the reforming catalyst bed 210 within each unit chamber 203 are calcium oxide and LaMn, respectively. 0.2 Fe 0.8 O3, LaMn 0.2 Fe 0.7 Ni 0.1 O3, LaMn 0.2 Fe 0.6 Ni 0.2 O3, LaMn 0.2 Fe 0.5 Ni 0.3 O3, LaMn 0.2 Fe 0.4 Ni 0.4 O3, LaMn 0.2 Fe 0.3 Ni 0.5 O3, LaMn 0.25 Fe 0.55 Ni 0.2 O3, LaMn 0.3 Fe 0.5 Ni 0.2 O3, LaMn 0.4 Fe 0.4 Ni 0.2 O3, LaMn 0.15 Fe 0.65 Ni 0.2 O3, LaMn 0.1 Fe 0.7 Ni 0.2 O3, LaMn 0.05 Fe 0.75 Ni 0.2 O3; First, methane is used to reduce the catalysts in unit cavities 2 to 13 (the reduction temperature is controlled at 700℃ by a hot air heating mechanism 208) to reduce the lanthanum-manganese-iron-nickel composite oxide catalysts to a reduced state. Then, blast furnace gas is first introduced into the odd-numbered unit cavities 203 for adsorption reforming, followed by adsorption reforming into the even-numbered unit cavities 203 (while methane and hot air are simultaneously introduced into the odd-numbered unit cavities 203 for reduction). Sampling and testing are performed through the corresponding unit exhaust branch pipe 2032 during the adsorption reforming process in each unit cavity 203. One round is defined as all unit cavities 203 undergoing one adsorption reforming treatment, and the above operation is repeated for 20 rounds. The sampling and testing results of each unit cavity 203 are shown in the table below:

[0158]

[0159] The lanthanum manganese iron-nickel composite oxides (LaMn) in the above application example 1 x Fe y Ni z The preparation method of O3 is as follows:

[0160] Lanthanum nitrate, manganese nitrate, ferric nitrate, and nickel nitrate were mixed in deionized water according to a La, Mn, Fe, and Ni ion molar ratio of 1:x:y:z (where x, y, and z represent the molar contents of manganese, iron, and nickel in each target catalyst, respectively), resulting in a mixed salt solution with a total metal salt mass concentration of approximately 30%. Anhydrous citric acid, based on 1.5 times the total molar amount of metal ions, was then added to the mixed salt solution and stirred with a glass rod until completely dissolved, yielding a clear, transparent, and precipitate-free precursor solution. A magnetic stir bar was then added to a beaker containing the precursor solution, and the mixture was transferred to a water bath magnetic stirrer. Stirring was initiated, and the mixture was heated to 80°C for a hydrothermal reaction for 4 hours, yielding a honey-like wet gel product. The magnetic stir bar was then removed, and the wet gel product was transferred to a forced-air drying oven and dried at 120°C for 12 hours to obtain a fibrous precursor. The fibrous precursor was then placed in a muffle furnace and heated at 400°C for 4 hours. The temperature was then increased to 1200°C at a rate of 4°C / min, and calcined at this temperature for 4 hours to obtain the target catalysts LaMn. x Fe y Ni z O3.

Claims

1. An integrated CO2 in-situ reforming system, characterized in that: The system includes a housing (1) and an inner cavity (2); the inner cavity (2) is divided from top to bottom into a reforming cavity (201) and a synthesis cavity (202) or the inner cavity (2) is divided in the horizontal direction into multiple (at least two) unit cavities (203); The reforming chamber (201) and the synthesis chamber (202) are connected; a carbon-containing gas input pipe (204) and a reforming gas output pipe (205) are connected to the reforming chamber (201); a reducing gas input pipe (206) and a synthesis gas output pipe (207) are connected to the synthesis chamber (202); a heating mechanism (208) is provided inside the synthesis chamber (202); both the reforming chamber (201) and the synthesis chamber (202) are filled with reforming catalyst particles (209). The multiple unit cavities (203) are not interconnected, and each unit cavity (203) is independently equipped with a heating mechanism (208) and a reforming catalyst bed (210); a carbon-containing gas input pipe (204) and a reforming gas output pipe (205) are connected to at least one unit cavity (203); a reducing gas input pipe (206) and a synthesis gas output pipe (207) are connected to at least one unit cavity (203).

2. The system according to claim 1, characterized in that: The reforming chamber (201) and the synthesis chamber (202) are connected by multiple flat channels (211) that are wide at the ends and narrow in the middle; or the reforming chamber (201) and the synthesis chamber (202) are connected by multiple evenly distributed round or square tubes.

3. The system according to claim 1 or 2, characterized in that: A uniform discharge mechanism is provided at the bottom discharge port of the synthesis chamber (202). The uniform discharge mechanism is composed of multiple distribution cones (212) that are pointed at the top and wide at the bottom, evenly distributed at intervals. The inclination angle of the cone surface of the distribution cone (212) is greater than the packing angle of the reforming catalyst particles (209). Preferably, the inclination angle of the cone surface of the distribution cone (212) is 2~10° larger than the packing angle of the reforming catalyst particles (209). Preferably, the distribution cone (212) is a square pyramid, and the distance between the distribution cones (212) and between the distribution cones (212) and the inner wall of the synthesis chamber (202) is 20~80mm. The bottom side length of the distribution cone (212) is 100~800mm.

4. The system according to any one of claims 1-3, characterized in that: The bottom discharge port of the synthesis chamber (202) is connected to the top feed port of the reforming chamber (201) through the catalyst circulation conveying device (213); the reforming catalyst particles (209) circulate between the reforming chamber (201) and the synthesis chamber (202) through the catalyst circulation conveying device (213); preferably, a material temperature detector (e.g., thermocouple) and a material flow regulating valve (e.g., star-shaped discharge valve) are provided on the catalyst circulation conveying device (213).

5. The system according to any one of claims 1-4, characterized in that: The heating mechanism (208) is an electric heating wire, an electric heating plate, a hot air duct network, or an oxygen supply duct network; and / or Gas temperature detectors (e.g., thermocouples) and gas flow regulating valves (e.g., pneumatic regulating valves) are independently installed on the carbon gas input pipeline (204), reforming gas output pipeline (205), reducing gas input pipeline (206), and synthesis gas output pipeline (207).

6. The system according to claim 5, characterized in that: The heating mechanism (208) is a hot air duct network, which includes an air inlet pipe (2081), a heat exchange tube array (2082), and an exhaust pipe (2083) connected in series. The heat exchange tube array (2082) is set inside the synthesis chamber (202) or is independently set in each unit chamber (203). The air inlet pipe (2081) and the exhaust pipe (2083) are set outside the shell (1), and the air inlet pipe (2081) is connected to the hot air furnace (2084). Preferably, the heat exchange tube array (2082) in each unit chamber (203) is connected to the air inlet pipe (2081) and the exhaust pipe (2083) through independent air inlet branch pipes and exhaust branch pipes, respectively.

7. The system according to claim 5, characterized in that: The heating mechanism (208) is an oxygen supply network, which includes a main oxygen supply pipeline (2085) and several oxygen supply branch pipes (2086). The main oxygen supply pipeline (2085) is connected to the synthesis chamber (202) through several oxygen supply branch pipes (2086), or the main oxygen supply pipeline (2085) is connected to each unit chamber (203) through several oxygen supply branch pipes (2086). Each of the main oxygen supply pipeline (2085) and several oxygen supply branch pipes (2086) is independently equipped with a throttling valve.

8. The system according to any one of claims 1-7, characterized in that: Each unit cavity (203) is provided with a unit intake branch pipe (2031) and a unit exhaust branch pipe (2032); all unit cavities (203) are arranged in a horizontal direction along the inner cavity (2), wherein: the unit intake branch pipe (2031) of all unit cavities (203) located in odd-numbered positions is connected to the first intake main pipe (2033), and the unit exhaust branch pipe (2032) of all unit cavities (203) located in odd-numbered positions is connected to the first exhaust main pipe (2034); the unit intake branch pipe (2031) of all unit cavities (203) located in even-numbered positions is connected to the second intake main pipe (2034). 5) All unit exhaust branch pipes (2032) of all unit cavities (203) located in even-numbered positions are connected to the second exhaust main pipe (2036); the first intake main pipe (2033) and the second intake main pipe (2035) are connected to the carbon-containing gas input pipe (204) and the reducing gas input pipe (206) respectively through independent valve pipes (2037); the first exhaust main pipe (2034) and the second exhaust main pipe (2036) are connected to the reforming gas output pipe (205) and the synthesis gas output pipe (207) respectively through independent valve pipes (2037).

9. The system according to any one of claims 1-8, characterized in that: The reforming catalyst in the reforming catalyst particles (209) and the reforming catalyst bed (210) is calcium oxide and / or lanthanum manganese iron nickel composite oxide.

10. The system according to claim 9, characterized in that: The lanthanum manganese iron nickel complex oxide has a structural formula of LaMn x Fe y Ni z O3, wherein: 0.05≤x≤0.45, 0.1≤y≤0.95, 0≤z≤0.5; preferably 0.1≤x≤0.3, 0.3≤y≤0.8, 0.1≤z≤0.4; more preferably 0.15≤x≤0.25, 0.45≤y≤0.65, 0.2≤z≤0.3; x+y+z=1.

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