Methanation fixed bed reactor
By employing a multi-layered vessel wall design and a thermochromic aerogel coating in the methanation reactor, the problems of reactor overheating and safety hazards were solved, achieving efficient heat transfer and intelligent overheat protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-10
AI Technical Summary
The methanation reactor has an external wall temperature that exceeds the design safety threshold, and its operation and maintenance rely on manual inspections, which leads to delays in responding to safety hazards.
The reactor wall adopts a multi-layer structure, including a metal shell, a refractory layer, a heat insulation layer, an acid-resistant coating, and an aerogel insulation layer. It prevents overheating through gradient heat conduction and uses the thermochromic properties of the aerogel insulation layer to provide timely warning.
It effectively avoids long-term overheating of the reactor, reduces the risk of equipment deformation and material failure, achieves efficient heat transfer and intelligent overheating prevention, and improves the safety and reliability of the reactor.
Smart Images
Figure CN121819686A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of chemical equipment, in particular to a methanation fixed bed reactor. BACKGROUND
[0002] China has the energy status of rich coal, poor oil and little gas. In recent years, with the rapid increase of natural gas demand in China, the gap between supply and demand of domestic natural gas has gradually increased. Coal-based natural gas is a process technology for producing natural gas from coal, which can convert coal into clean fuel CH4 for long-distance transportation, and is an important way to optimize the domestic energy structure, alleviate the contradiction between supply and demand of natural gas and realize efficient and clean conversion of coal.
[0003] Methanation is the core technology of coal-based natural gas, which is the synthesis of CO, CO2 and H2 in synthesis gas under the action of catalyst at a certain temperature, pressure and catalyst. The reactor suitable for coal gas methanation is mainly a fixed bed reactor, which has the advantages of good high temperature resistance, simple structure, convenient operation, large amount of catalyst loading and high reaction conversion rate. However, the methanation reaction is an exothermic reaction, and the reaction temperature is 500℃-700℃. The methanation process is violent (ΔH = -206 kJ / mol), the heat is not uniformly distributed in the reactor, and the temperature is too high to easily cause catalyst coking and reactor overtemperature, for example, the reactor outer wall temperature exceeds the design safety threshold, and there is a local hot spot phenomenon. Long-term overtemperature of the reactor can easily lead to ablation of the heat preservation material, structural deformation, and even cause high temperature creep failure of the reactor wall material. Moreover, the operation and maintenance of the reactor depend on manual inspection and detection of temperature, which has a safety hazard response delay. SUMMARY
[0004] The purpose of the present application is to overcome the problems of the prior art, such as the reactor outer wall temperature exceeding the design safety threshold, the operation and maintenance depending on manual inspection, and the safety hazard response delay. The present application provides a methanation fixed bed reactor, which has a reactor wall with a multi-layer structure, including a metal shell, a refractory layer, a heat insulation layer, an acid-resistant coating and an aerogel heat preservation layer, so as to perform gradient heat conduction through the reactor wall with multi-layer structure, and avoid long-term overtemperature of the reactor. At the same time, the thermal discoloration of the aerogel heat preservation layer can timely alarm and realize rapid response to abnormal heat state.
[0005] To achieve the above objectives, in a first aspect, the present invention provides a methanation fixed-bed reactor, comprising a reactor wall having a multi-layered structure and a reaction chamber defined by the reactor wall, wherein the reactor wall having a multi-layered structure includes a metal shell, a refractory layer, a heat insulation layer, an acid-resistant coating, and an aerogel insulation layer; and along the direction from the metal shell toward the center of the reactor, the heat insulation layer, the refractory layer, and the acid-resistant coating are sequentially disposed on the inner wall of the metal shell, and the aerogel insulation layer is disposed on the outer wall of the metal shell; wherein the thickness of the refractory layer and the heat insulation layer is sufficient to keep the outer surface temperature of the metal shell below 300°C.
[0006] Preferably, the thermal conductivity of the refractory layer is less than that of the insulation layer.
[0007] Preferably, the thickness of the refractory layer is 100~150mm; the thickness of the heat insulation layer is 200~250mm; the thickness of the aerogel insulation layer is sufficient to ensure that the outer surface temperature of the metal shell is higher than 180℃, preferably, the thickness of the aerogel insulation layer is 5mm~10mm.
[0008] Preferably, the refractory layer (3) is formed by casting a castable containing calcium aluminate cement and corundum, and the material of the refractory layer (3) includes Al2O3, SiO2 and Fe2O3.
[0009] Preferably, the heat insulation layer (2) is formed by casting a castable containing calcium aluminate cement, and the material of the heat insulation layer (2) includes Al2O3, SiO2 and Fe2O3.
[0010] Preferably, the height difference between the construction joint of the fire-resistant layer and the construction joint of the heat insulation layer is 100-200mm.
[0011] Preferably, the methanation fixed-bed reactor further includes several temperature detection devices disposed on the outer wall of the metal shell.
[0012] Preferably, the plurality of temperature detection devices are a plurality of thermocouples, and the plurality of temperature detection devices are arranged at intervals along the circumferential direction of the outer wall of the methanation fixed-bed reactor.
[0013] Preferably, the methanation fixed-bed reactor further includes a controller for increasing or decreasing the flow rate of feed gas into the methanation fixed-bed reactor based on the temperature data obtained by the temperature detection device.
[0014] The technical solution of the present invention has at least the following beneficial effects: (1) The reactor wall with a multi-layer structure, with a refractory layer and a heat insulation layer set inside the metal shell, blocks the transfer path of abnormal heat to the reactor wall. Gradient heat conduction is achieved through the multi-layer reactor wall, thus preventing the reactor from overheating for a long time. Among them, the refractory layer and the heat insulation layer prevent the reactor wall from overheating, while the aerogel insulation layer insulates the reactor wall to prevent the temperature difference between the inside and outside of the reactor wall from becoming too large when the ambient temperature changes, which would cause gas condensation and damage to the reactor.
[0015] (2) The aerogel insulation layer set on the outside of the metal shell can be a thermochromic aerogel coating. The thermochromic properties of the aerogel insulation layer can provide timely warnings to enable rapid subsequent response and reduce the risk of equipment deformation and material failure caused by reactor wall overheating. This helps to solve the industry pain point of "uncontrollable external wall overheating and difficulty in continuous safe operation" caused by the contradiction between violent exothermic reaction and passive temperature control in existing fixed-bed methanation reactors, and ultimately achieves an integrated upgrade of the reactor to "efficient heat transfer, intelligent overheat protection, and intrinsic safety". Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of the methanation fixed-bed reactor provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the construction joint structure of the heat insulation layer and refractory layer of the methanation fixed-bed reactor provided in the embodiments of the present invention.
[0017] The attached figures are labeled as follows: 1. Metal shell; 2. Insulation layer; 3. Fire-resistant layer; 4. Aerogel insulation layer; 5. Construction joint. Detailed Implementation
[0018] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0019] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0020] This invention provides a methanation fixed-bed reactor, see [link to relevant documentation]. Figure 1The reactor includes a reactor wall with a multi-layered structure and a reaction chamber defined by the reactor wall. The reactor wall with a multi-layered structure includes a metal shell 1, a refractory layer 3, a heat insulation layer 2, and an aerogel insulation layer 4. Along the direction from the metal shell 1 to the center of the reactor, the heat insulation layer 2 and the refractory layer 3 are sequentially disposed on the inner wall of the metal shell 1, and the aerogel insulation layer 4 is disposed on the outer wall of the metal shell 1. The thickness of the refractory layer 3 and the heat insulation layer 2 is such that the outer surface temperature of the metal shell 1 is below 300°C.
[0021] In this invention, "the direction along the metal shell 1 pointing towards the center of the reactor" is... Figure 1 The X direction is shown in the figure. Thus, along the X direction, a metal-insulation layer 2-fire-resistant layer 3-reaction chamber is formed.
[0022] Therefore, by using a multi-layered reactor wall, the refractory layer 3 and the insulation layer 2 located inside the metal shell 1 block the transfer path of abnormal heat to the reactor wall. This multi-layered reactor wall then facilitates gradient heat conduction, preventing the reactor from overheating for extended periods. The refractory and insulation layers prevent overheating of the reactor wall, while the aerogel insulation layer insulates the wall, preventing excessive temperature differences between the inside and outside of the wall due to ambient temperature changes, which could lead to gas condensation and damage to the reactor.
[0023] Additionally, the aerogel insulation layer 4 installed on the outside of the metal shell 1 can be a thermochromic aerogel coating, meaning it can change color upon exceeding a certain temperature to provide timely warnings of overheated areas. This thermochromic effect of the aerogel insulation layer 4 allows for prompt alerts and rapid subsequent response, reducing the risk of equipment deformation and material failure caused by reactor wall overheating. This helps address the industry pain point of existing fixed-bed methanation reactors, which suffer from "uncontrollable external wall overheating and difficulty in maintaining safe operation" due to the contradiction between intense exothermic reaction and passive temperature control. Ultimately, it achieves an integrated upgrade of the reactor to "high-efficiency heat transfer, intelligent overheat protection, and intrinsic safety."
[0024] In some embodiments, the thermal conductivity of the refractory layer 3 is lower than that of the insulation layer 2. Therefore, when the insulation layer 2 and the refractory layer 3 are sequentially disposed on the inner wall of the metal casing 1, the high-temperature reaction medium in the reaction chamber preferentially contacts the refractory layer 3, which is closer to the center. Since the refractory layer 3 has a lower thermal conductivity, it can guide axial heat transfer and reduce radial heat transfer.
[0025] In some embodiments, the thickness of the refractory layer 3 is 100-150 mm; the thickness of the heat insulation layer 2 is 200-250 mm. The thickness of the aerogel insulation layer 4 is sufficient to keep the outer surface temperature of the metal shell 1 above 180°C; preferably, the thickness of the aerogel insulation layer 4 is 5 mm-10 mm. When the thicknesses of the refractory layer 3, the heat insulation layer 2, and the aerogel insulation layer 4 are within the aforementioned suitable ranges, it is beneficial to maintain the outer surface temperature of the metal shell 1 at 180°C-300°C.
[0026] In some embodiments, the refractory layer 3 is formed by casting a castable containing calcium aluminate cement and corundum, and the material of the refractory layer 3 includes Al2O3, SiO2, and Fe2O3. As an example, the mass percentage of Al2O3 in the refractory layer 3 can be 93% to 96%, the mass percentage of Fe2O3 in the refractory layer 3 can be less than or equal to 0.5%, and the mass percentage of SiO2 in the refractory layer 3 can be less than or equal to 0.5%.
[0027] In some embodiments, the insulation layer 2 is formed by casting a castable containing calcium aluminate cement, and the material of the insulation layer (2) includes Al2O3, SiO2, and Fe2O3. As an example, the mass percentage of Al2O3 in the insulation layer 2 can be 40% to 90%, the mass percentage of SiO2 in the insulation layer 2 can be 0.2% to 30%, and the mass percentage of Fe2O3 in the insulation layer 2 can be less than or equal to 0.5%.
[0028] In some embodiments, the height difference between the construction joint 5 of the refractory layer 3 and the construction joint 5 of the insulation layer 2 is 100-200mm. In this invention, a "construction joint" refers to a gap with certain interface characteristics formed at the junction of castable materials poured in successive stages during the construction process, due to construction process requirements (such as segmented construction or layered pouring). This gap is caused by the "time interval" or "spatial segmentation" of the construction stages and belongs to an interface bonding layer without a solid gap. Therefore, by staggering the construction joint 5 of the refractory layer 3 and the construction joint 5 of the insulation layer 2 in the longitudinal direction, i.e., by staggered construction, heat transfer to the vessel wall can be prevented.
[0029] In some embodiments, the aerogel insulation layer 4 is prepared by the following method: S1. Place the silica gel in a supercritical fluid drying dry pressure container, lower its temperature and introduce CO2 to achieve liquid-gas two-phase equilibrium, then raise the temperature at a certain rate to reach the critical state, so that all the liquid in the gel pores is converted into the critical liquid, and slowly release the CO2 fluid until the ambient pressure and room temperature are reached to obtain silica aerogel solid. S2. The prepared silica aerogel solid is dispersed to obtain aerogel microspheres with a diameter of less than 100µm and silica microsphere ink particles with a diameter of less than 200µm. S3. Prepare a polymer slurry by mixing acrylic emulsion, aqueous resin, dispersant, thickener, binder, and glass microspheres; S4. The aerogel microspheres and silicon microspheres are mixed with polymer slurry to prepare aerogel slurry.
[0030] In some embodiments, the methanation fixed-bed reactor further includes several temperature detection devices disposed on the outer wall of the metal shell.
[0031] In some embodiments, the aerogel slurry can be sprayed onto the reactor wall to form an aerogel insulation layer 4. The aerogel slurry can be a thermochromic aerogel slurry, such as the aerogel slurry from Anhui Honghui New Material Technology Co., Ltd.
[0032] In some embodiments, the plurality of temperature detection devices are a plurality of thermocouples, which are spaced apart circumferentially along the outer wall of the methanation fixed-bed reactor. As an example, the plurality of thermocouples can be arranged in several rings spaced apart circumferentially along the outer wall of the metal shell, thereby enabling real-time detection of the temperature at various points on the reactor wall, and thus generating a real-time temperature field cloud map of the outer wall to predict overheating trends.
[0033] In some embodiments, the methanation fixed-bed reactor further includes a controller for increasing or decreasing the flow rate of feed gas into the methanation fixed-bed reactor based on temperature data acquired by the temperature sensing devices. As an example, when the temperature data acquired by at least one temperature sensing device exceeds 300°C and remains so for a certain period, the flow rate of feed gas into the methanation fixed-bed reactor is reduced. When the temperature data acquired by at least one temperature sensing device is below 180°C and remains so for a certain period, the flow rate of feed gas into the methanation fixed-bed reactor is increased.
[0034] The present invention will be further described below through embodiments, but the scope of protection of the present invention is not limited thereto.
[0035] Example 1 This embodiment illustrates the methanation fixed-bed reactor provided by the present invention. Please refer to [link to relevant documentation] for details regarding this methanation fixed-bed reactor. Figures 1-2 , specifically, The methanation fixed-bed reactor includes a reactor wall with a multi-layered structure and a reaction chamber defined by the reactor wall. The reactor wall with a multi-layered structure includes a metal shell 1, a refractory layer 3, a heat insulation layer 2, and an aerogel insulation layer 4; and a plurality of thermocouples spaced circumferentially along the outer wall of the methanation fixed-bed reactor. Along the direction from the metal shell 1 towards the center of the reactor, the heat insulation layer 2 and the refractory layer 3 are sequentially disposed on the inner wall of the metal shell 1, and the aerogel insulation layer 4 is disposed on the outer wall of the metal shell 1.
[0036] The thermal conductivity of the refractory layer 3 is less than that of the insulation layer 2. The thickness of the refractory layer 3 is 100 mm, the thickness of the insulation layer 2 is 200 mm, and the thickness of the aerogel insulation layer 4 is 5 mm. The height difference between the construction joint of the refractory layer 3 and the construction joint of the insulation layer 4 is 100 mm.
[0037] The aerogel insulation layer 4 is formed by spraying thermochromic aerogel slurry, which is made from aerogel slurry from Anhui Honghui New Material Technology Co., Ltd.
[0038] The refractory layer 3 is formed by casting a castable containing calcium aluminate cement and corundum. The materials of the refractory layer 3 include Al2O3, SiO2, and Fe2O3. The refractory layer 3 is formed by casting a pure calcium aluminate cement high-strength corundum castable from China Steel Group Luoyang Refractory Materials Research Institute Co., Ltd.
[0039] The insulation layer 2 is formed by casting a castable containing calcium aluminate cement. The materials of the insulation layer 2 include Al2O3, SiO2, and Fe2O3. The insulation layer 2 is formed by casting a pure calcium aluminate cement heat-insulating and refractory castable using materials from China Steel Group Luoyang Refractory Materials Research Institute Co., Ltd.
[0040] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A methanation fixed-bed reactor, characterized in that, It includes a reactor wall with a multi-layered structure and a reaction chamber defined by the reactor wall. The reactor wall with a multi-layer structure includes a metal shell (1), a refractory layer (3), a heat insulation layer (2), and an aerogel insulation layer (4); and along the direction from the metal shell (1) toward the center of the reactor, the heat insulation layer (2) and the refractory layer (3) are sequentially disposed on the inner wall of the metal shell (1), and the aerogel insulation layer (4) is disposed on the outer wall of the metal shell (1); The thickness of the fire-resistant layer (3) and the heat insulation layer (2) is such that the outer surface temperature of the metal shell (1) is below 300°C.
2. The methanation fixed-bed reactor according to claim 1, characterized in that, The thermal conductivity of the refractory layer (3) is less than that of the insulation layer (2).
3. The methanation fixed-bed reactor according to claim 1, characterized in that, The thickness of the fire-resistant layer (3) is 100~150mm; and / or the thickness of the heat insulation layer (2) is 200~250mm.
4. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The thickness of the aerogel insulation layer (4) is such that the outer surface temperature of the metal shell (1) is higher than 180°C. Preferably, the thickness of the aerogel insulation layer (4) is 5 mm to 10 mm.
5. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The refractory layer (3) is formed by casting a castable containing calcium aluminate cement and corundum. The material of the refractory layer (3) includes Al2O3, SiO2 and Fe2O3.
6. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The heat insulation layer (2) is formed by casting a castable containing calcium aluminate cement, and the material of the heat insulation layer (2) includes Al2O3, SiO2 and Fe2O3.
7. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The height difference between the construction joint (5) of the fire-resistant layer (3) and the construction joint (5) of the heat insulation layer (2) is 100-200mm.
8. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The methanation fixed-bed reactor also includes several temperature detection devices disposed on the outer wall of the metal shell.
9. The methanation fixed-bed reactor according to any one of claims 1-3, characterized in that, The plurality of temperature detection devices are a plurality of thermocouples, and the plurality of temperature detection devices are arranged at intervals along the circumferential direction of the outer wall of the methanation fixed bed reactor.
10. The methanation fixed-bed reactor according to claim 1, characterized in that, The methanation fixed-bed reactor also includes a controller for increasing or decreasing the flow rate of feed gas into the methanation fixed-bed reactor based on temperature data obtained from the temperature detection device.