An in-situ carbonate reduction system using indirect heating and its preparation process
By using an indirect heating and counter-flow in-situ carbonate reduction system, the safety hazards and high energy consumption of existing carbonate decomposition devices have been solved, achieving efficient and safe carbonate decomposition and reduction, and improving syngas quality and reaction rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN CEMENT IND DESIGN & RES INST CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-07-31
AI Technical Summary
Existing carbonate decomposition units have significant safety hazards, high reduction pressure, limited product quality, and poor material flowability. In particular, they are prone to explosion when hydrogen molecules are introduced in an oxidizing atmosphere. The combustion of fossil fuels increases CO2 emissions, and the introduction of nitrogen affects the quality of syngas. Wet and sticky materials result in poor flowability.
The in-situ carbonate reduction system employs indirect heating. Through the design of rotary reaction components and heating sleeve components, it utilizes high-temperature gas for indirect heat transfer, combined with the reaction of carbonate and hydrogen molecules in a counter-flowing manner. The reaction parameters are monitored and adjusted in real time to ensure that the reaction takes place in a reducing atmosphere.
It significantly reduces carbon emission reduction energy consumption and costs, improves syngas quality and reaction rate, avoids explosion risks, improves material flowability and heat utilization efficiency, and achieves efficient and directional carbonate decomposition and in-situ reduction.
Smart Images
Figure CN122479702A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of carbonate reduction technology, and particularly relates to an in-situ carbonate reduction system using indirect heating and its preparation process. Background Technology
[0002] Carbonates are crucial raw materials for heavy-emission industries such as steel, cement, and refractory materials. Their processing and use generate significant CO2 emissions, placing immense pressure on achieving carbon neutrality goals. In-situ reduction and decomposition of carbonates with hydrogen donor molecules is an effective emission reduction method. This process not only reduces emissions but also produces high-value syngas, which can then be supplied to downstream industries to synthesize high-value-added chemical products.
[0003] Currently, commonly used carbonate decomposition devices mainly include suspension decomposition furnaces and rotary kilns. However, these existing technologies have the following significant problems in practical applications:
[0004] Significant safety hazards exist: Existing equipment mostly uses fossil fuels for direct heating, requiring an oxidizing atmosphere to ensure combustion. However, the coupling reduction reaction between carbonates and hydrogen donor molecules must occur in a reducing atmosphere. Introducing hydrogen donor molecules into an oxidizing atmosphere could easily trigger a major explosion hazard.
[0005] High reduction pressure: Direct combustion of fossil fuels for heating produces additional CO2, which not only increases the environmental burden but also further intensifies the reduction pressure in the reactor, making it unfavorable for the reaction to proceed in the reduction direction.
[0006] Product quality is limited: fuel combustion usually requires air to assist combustion, which introduces a large amount of nitrogen, resulting in a decrease in the quality of the generated syngas and significantly increasing the pressure on downstream processes to purify the syngas.
[0007] Poor material flowability: Water vapor is generated during the reduction reaction. If the ventilation design of the device is not reasonable, water vapor can easily condense on the carbonate material, causing the material to become wet, sticky, and clumpy, which seriously reduces the flowability of the material. Summary of the Invention
[0008] To address the problems existing in the prior art, this invention provides a carbonate in-situ reduction system and its preparation process using indirect heating, which achieves efficient and directional conversion of carbonate decomposition and in-situ reduction reactions, significantly reduces the overall energy consumption and cost of carbon emission reduction, and greatly improves the overall thermal utilization efficiency and reaction rate.
[0009] This invention is achieved by providing an in-situ carbonate reduction system using indirect heating, comprising: A rotary reaction component, including a reactor, wherein a head mechanical seal and a tail mechanical seal are respectively provided at both ends of the reactor; A heating sleeve component is fitted outside the reactor and parallel to the reactor axis. A heating gas inlet is provided on the heating sleeve component near the head seal. The head mechanical seal is provided with a feed port and a first gas channel, the first gas channel being an inlet channel for supplying hydrogen gas; the tail mechanical seal is provided with a material inlet and a second gas channel, the second gas channel being an outlet channel for supplying hydrogen molecules.
[0010] Furthermore, the reactor is equipped with a lifting plate, which has a single-section or segmented structure in the axial direction of the reactor.
[0011] Furthermore, a distribution plate is provided inside the heating sleeve component near the heating gas inlet. The distribution plate divides the inner cavity of the heating sleeve component into a distribution chamber and a heating chamber, and the distribution chamber is connected to the heating gas inlet.
[0012] Furthermore, a damping plate is provided on the inner wall of the heating sleeve component, and the damping plate is a swirl plate, a straight plate, or an inclined plate.
[0013] Furthermore, the ratio of the length of the reactor to its effective inner diameter is (4-9):1.
[0014] Furthermore, the reactor near the mechanical seal is provided with a partially enlarged section, the length of which is 2% to 10% of the total length of the reactor, and the diameter of which is increased by 100 to 600 mm compared to the original diameter.
[0015] Furthermore, the discharge port is equipped with a flap valve for airlocking.
[0016] On the other hand, a process for preparing carbonates using any of the reduction systems described above is provided, comprising the following steps: Low-temperature gas is heated to 600~1000℃ to form high-temperature gas; The carbonate material is fed into the reactor of the rotary reaction unit from the material inlet; The high-temperature gas is introduced into the heating sleeve component, and heat is indirectly and evenly transferred to the carbonate in the reactor through external heating. Hydrogen molecules are introduced into the reactor, and the carbonate undergoes an in-situ reduction reaction with the hydrogen molecules under the energy provided by the high-temperature gas to generate metal oxides and syngas. The completely decomposed material is discharged through the feed port, and the synthesis gas is discharged through the second gas channel.
[0017] Furthermore, the carbonate and high-temperature gas flow in a counter-current manner within the reactor. The carbonate enters the front section of the reactor and gradually rises from a low temperature to 400-600°C. In the rear section of the reactor, the reaction temperature range for decomposition and reduction is reached, and the carbonate undergoes an in-situ reduction reaction with the hydrogen-donating molecules.
[0018] Furthermore, it also includes real-time control of the flow rate and temperature of the high-temperature gas, the flow rate of hydrogen molecules, and the residence time of carbonates in the reactor based on the monitoring of the temperature distribution inside the reactor, the composition of the outlet syngas, and the temperature of the high-temperature gas before and after heating. Specifically: When the concentration ratio of CO / H2 in the syngas is detected to be lower than the first threshold, the intelligent platform determines that the carbonate reduction rate is low and then reduces the reactor speed. When the reactor head temperature is detected to be below the second threshold, the temperature T1' of the cryogenic gas is increased. When the temperature at the reactor head is normal and the temperature at the tail is below the third threshold, the flow rate of the high-temperature gas is increased.
[0019] The advantages and technical effects of this invention are as follows: By adopting the above technical solution, the heat source and the reaction atmosphere are completely isolated in physical space, eliminating the risk of explosion at the source; at the same time, the direct combustion of fossil fuels in the reaction system is avoided, no additional combustion CO2 is produced, and no nitrogen in the air is introduced. Thus, under the premise of ensuring high safety, efficient and directional conversion of carbonate decomposition and in-situ reduction reaction is achieved, significantly reducing the overall energy consumption and cost of carbon emission reduction, and greatly improving the quality and economic value of the produced syngas.
[0020] The counter-current flow of materials and hydrogen-donating molecules enhances the driving force of the reaction, favoring the reaction towards the generation of syngas and improving the conversion rate. Simultaneously, the carbonate material, dynamically tumbling within the rotary reactor, continuously refreshes its heating surface, overcoming the poor thermal conductivity of static packing and enabling uniform and efficient heat extraction from the reactor walls. This significantly improves overall thermal efficiency and reaction rate. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of the restoration system provided in an embodiment of the present invention; Figure 2 This is a process principle diagram provided in an embodiment of the present invention.
[0022] In the picture: 10. Head mechanical seal; 11. First gas passage; 12. Discharge port; 20. Reactor; 30. Tail mechanical seal; 31. Material inlet; 32. Second gas passage; 40. Heating sleeve components; 41. High-temperature resistant air distribution plate; 42. High-temperature gas inlet. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0024] It should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.
[0025] like Figure 1 As shown, this application provides a carbonate in-situ reduction system employing indirect heating, comprising: A rotary reaction unit includes a reactor 20, wherein a head mechanical seal 10 and a tail mechanical seal 30 are respectively provided at both ends of the reactor 20; A heating sleeve component 40 is sleeved outside the reactor 20 and parallel to the axial direction of the reactor 20. A heating gas inlet is provided on the heating sleeve component 40 near the head seal. The head mechanical seal 10 is provided with a discharge port 12 and a first gas channel 11, the first gas channel 11 being an inlet channel for supplying hydrogen gas; the tail mechanical seal 30 is provided with a material inlet 31 and a second gas channel 32, the second gas channel 32 being an outlet channel for supplying hydrogen molecules.
[0026] As reactor 20 rotates, the material gradually moves to the head of reactor 20. The residence time of the material in reactor 20 can be controlled by adjusting the rotation speed of reactor 20, depending on the required reaction time. Completely decomposed material leaves the device through discharge port 12. Hydrogen molecules enter the device through the gas channel. Depending on the reaction rate, the reaction can be carried out in the same direction as or against the material flow direction; generally, a reverse reaction is chosen because it provides a stronger driving force and a higher conversion rate. The energy required for the reaction is supplied by high-temperature gas through the heating sleeve component 40, and then transferred to reactor 20. The high-temperature gas is evenly distributed into the heating sleeve through the high-temperature resistant air distribution plate 41.
[0027] During operation, reactor 20 rotates. Both the head mechanical seal 10 and the tail mechanical seal 30 include rotating and stationary components. The rotating component rotates with reactor 20, while the stationary component remains relatively stationary. Gas and material conveying pipelines are connected to the stationary component. The head mechanical seal 10 and tail mechanical seal 30 are interconnected with reactor 20. This ensures effective connection between the gas and material and the rotating reactor 20 during transport. The head mechanical seal 10 and tail mechanical seal 30 can be DNF125ZT-BXG model mechanical seals manufactured by Shandong Haixuan Machinery Technology Co., Ltd.
[0028] In some embodiments, in order to disperse the material in the reactor 20, increase the contact area with the gas, and accelerate the reaction rate, a lifting plate is provided inside the reactor 20, and the lifting plate has a one-piece or segmented structure in the axial direction of the reactor 20.
[0029] In some embodiments, a distribution plate is further provided inside the heating sleeve component 40 near the heating gas inlet. The distribution plate divides the inner cavity of the heating sleeve component 40 into a distribution chamber and a heating chamber, and the distribution chamber is connected to the heating gas inlet. Specifically, the distribution plate is made of a high-temperature resistant material, and the high-temperature gas enters the distribution chamber and is then evenly distributed into the heating chamber after passing through the high-temperature resistant distribution plate.
[0030] In some embodiments, in order to prolong the residence time of the airflow, increase the heat transfer efficiency, and increase the heat utilization rate, a damping plate is provided on the inner wall of the heating sleeve component 40. The damping plate is a swirl plate, a straight plate, or an inclined plate.
[0031] Since only the decomposition and reduction reactions of carbonates occur within reactor 20, the effective ratio of length to inner diameter is determined based on the material heating time and reaction kinetics. If reactor 20 is too short, the residence time is insufficient, and the reaction rate cannot be achieved. If reactor 20 is too long, heat and power are wasted. Therefore, the ratio of the length of reactor 20 to its effective inner diameter is (4-9):1.
[0032] In some embodiments, since the reduction reaction produces water vapor, in order to increase the ventilation area, prevent water vapor from condensing on the carbonate material and reduce the fluidity of the carbonate, the reactor 20 near the mechanical seal is provided with a local enlargement section. The length of the local enlargement section is 2% to 10% of the total length of the reactor 20, and the diameter of the local enlargement section is increased by 100 to 600 mm compared with the original diameter.
[0033] Preferably, the discharge port 12 is equipped with a flap valve for airlocking to prevent hydrogen molecule leakage or air ingress.
[0034] In some embodiments, based on the above structure, a control system is further included. The control system includes a data acquisition unit, a controller, and an output unit. The data acquisition unit is communicatively connected to the input terminal of the controller, and the output unit is communicatively connected to the output terminal of the controller. The control system can monitor reaction operating parameters and, according to the kinetic and thermodynamic parameters of the reaction in this process, adjust some operating parameters in real time to promote the in-situ decomposition and reduction of carbonates and eliminate CO2 generated by carbonate decomposition. By monitoring the temperature distribution inside reactor 20 and the composition of the outlet syngas, as well as the temperature before and after heating carbonates with high-temperature gas, the system can intelligently adjust the high-temperature gas flow rate and temperature, the flow rate of hydrogen molecules, and the residence time of carbonates in reactor 20 in real time to ensure the heating efficiency of the high-temperature gas and the decomposition and reduction rate of carbonates.
[0035] The data acquisition unit includes temperature sensors installed at the head and tail of reactor 20 and at both ends of the heating sleeve to monitor the temperature rise. Reactor 20 head temperature and the tail temperature of reactor 20 Preferably, the temperature sensor can be a type K or type S thermocouple; An infrared gas analyzer or laser analyzer is installed at the outlet of the second gas channel 32 to monitor the CO / H2 concentration ratio in real time and quantitatively. Gas mass flow meters deployed at high-temperature gas inlet 42 and first gas channel 11.
[0036] Preferably, the controller can be an industrial-grade PLC, such as the Siemens S7-1200 / 1500 series.
[0037] The output unit includes: The geared motor and dedicated frequency converter used to drive the rotation of reactor 20 are configured to reduce the rotation speed of reactor 20 and increase the material residence time when the CO / H2 concentration ratio is lower than the first threshold. The heater used for heating the cryogenic gas is configured to dynamically adjust the heating power based on the temperature feedback from the head of reactor 20.
[0038] The proportional control valve installed at the high-temperature gas inlet 42 is configured to increase the high-temperature gas flow rate when the tail temperature is insufficient.
[0039] like Figure 2 As shown, another aspect provides a process for preparing carbonates using any of the reduction systems described above, comprising the following steps: The low-temperature gas is heated to 600~1000℃ to form a high-temperature gas. Specifically, the preferred heating methods for the low-temperature gas are resistance wire heating, solar heating, microwave heating, plasma heating, or fossil fuel combustion heating. In this embodiment, plasma heating is used. When using a resistance wire heater, solar heater, or plasma heater, the preferred gas is carbon dioxide, nitrogen, argon, or air. In this embodiment, carbon dioxide gas is used and is recycled. The carbonate material is fed into the reactor 20 of the rotary reaction unit from the material inlet 31; The high-temperature gas is introduced into the heating sleeve component 40, and the heat is indirectly transferred to the carbonate in the reactor 20 in a uniform manner through external heating. Hydrogen molecules are introduced into reactor 20. The carbonate undergoes an in-situ reduction reaction with the hydrogen molecules under the energy provided by the high-temperature gas to generate metal oxides and synthesis gas. Specifically, the hydrogen molecules are hydrogen, methane or methanol. The completely decomposed material is discharged through the feed port 12, and the synthesis gas is discharged through the second gas channel 32.
[0040] Furthermore, the carbonate and the high-temperature gas flow in a counter-current manner within the reactor 20. The carbonate enters the front section of the reactor 20 and gradually rises from a low temperature to 400~600℃. In the rear section of the reactor 20, the reaction temperature range for decomposition and reduction is reached, and the carbonate undergoes an in-situ reduction reaction with the hydrogen-donating molecules. The energy required is provided by the high-temperature gas.
[0041] Furthermore, it also includes real-time control of the flow rate and temperature of the high-temperature gas, the flow rate of hydrogen molecules, and the residence time of carbonates in the reactor 20 based on the monitoring of the temperature distribution inside the reactor 20, the composition of the outlet syngas, and the temperature of the high-temperature gas before and after heating. Specifically: When the CO / H2 concentration ratio in the syngas is detected to be lower than the first threshold, it is determined that the carbonate reduction rate is low, and the rotation speed of reactor 20 is reduced accordingly. The specific first threshold is set according to the needs of the downstream synthesized products, and is usually no higher than 0.5.
[0042] When the temperature at the head of reactor 20 is found to be lower than the second threshold, the temperature T1' of the low-temperature gas is increased, where the second threshold is 600~800℃. When the temperature at the head of reactor 20 is normal and the temperature at the tail is below the third threshold, the flow rate of the high-temperature gas is increased.
[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A carbonate in-situ reduction system employing indirect heat supply, characterized by, include: A rotary reaction component, including a reactor, wherein a head mechanical seal and a tail mechanical seal are respectively provided at both ends of the reactor; A heating sleeve component is fitted outside the reactor and parallel to the reactor axis. A heating gas inlet is provided on the heating sleeve component near the head seal. The head mechanical seal is provided with a feed port and a first gas channel, the first gas channel being an inlet channel for supplying hydrogen gas; the tail mechanical seal is provided with a material inlet and a second gas channel, the second gas channel being an outlet channel for supplying hydrogen molecules.
2. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, The reactor is equipped with a lifting plate, which has a single-section or segmented structure in the axial direction of the reactor.
3. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, A distribution plate is provided inside the heating sleeve component near the heating gas inlet. The distribution plate divides the inner cavity of the heating sleeve component into a distribution chamber and a heating chamber. The distribution chamber is connected to the heating gas inlet.
4. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, The inner wall of the heating sleeve component is provided with a damping plate, which is a swirl plate, a straight plate, or an inclined plate.
5. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, The ratio of the length of the reactor to its effective inner diameter is (4-9):
1.
6. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, The reactor near the mechanical seal is provided with a partially enlarged section, the length of which is 2% to 10% of the total length of the reactor, and the diameter of which is increased by 100 to 600 mm compared to the original diameter.
7. The carbonate in-situ reduction system with indirect heat supply of claim 1, wherein, The discharge port is equipped with a flap valve for airlocking.
8. A process for the production of carbonates using the reduction system according to any one of claims 1 to 7, characterized in that, Includes the following steps: Low-temperature gas is heated to 600~1000℃ to form high-temperature gas; The carbonate material is fed into the reactor of the rotary reaction unit from the material inlet; The high-temperature gas is introduced into the heating sleeve component, and heat is indirectly and evenly transferred to the carbonate in the reactor through external heating. Hydrogen molecules are introduced into the reactor, and the carbonate undergoes an in-situ reduction reaction with the hydrogen molecules under the energy provided by the high-temperature gas to generate metal oxides and syngas. The completely decomposed material is discharged through the feed port, and the synthesis gas is discharged through the second gas channel.
9. The process of claim 1, wherein, The carbonate and high-temperature gas flow in a counter-current manner within the reactor. The carbonate enters the front section of the reactor and gradually rises from a low temperature to 400-600°C. In the rear section of the reactor, the reaction temperature range for decomposition and reduction is reached, and the carbonate undergoes an in-situ reduction reaction with hydrogen-donating molecules.
10. The process of claim 1, wherein, It also includes real-time control of the flow rate and temperature of the high-temperature gas, the flow rate of hydrogen molecules, and the residence time of carbonates in the reactor based on monitoring the temperature distribution inside the reactor, the composition of the outlet syngas, and the temperature of the high-temperature gas before and after heating. Specifically: When the concentration ratio of CO / H2 in the syngas is detected to be lower than the first threshold, the intelligent platform determines that the carbonate reduction rate is low and then reduces the reactor speed. When the reactor head temperature is detected to be below the second threshold, the temperature T1' of the cryogenic gas is increased. When the temperature at the reactor head is normal and the temperature at the tail is below the third threshold, the flow rate of the high-temperature gas is increased.