Heat removal method for preparing C2 hydrocarbon through oxidative coupling of methane and reaction furnace

Abstract

The invention belongs to the technical field of preparation of ethylene by oxidative coupling of methane, and relates to a heat removal method and a reaction furnace for preparation of C2 hydrocarbon by oxidative coupling of methane. Comprising the following steps that (1) methane and oxygen are introduced into a catalyst bed layer to make contact with a catalyst for a catalytic reaction, the methane is fed at a constant speed, the oxygen is fed in a gradually-increased mode, and the initial feeding amount enables the alkoxy-to-oxygen ratio to be kept at 7-10: 1; (2) when the hot-spot temperature exceeds 750 DEG C, heat removal is carried out, the hot-spot temperature is reduced to 700-730 DEG C, and heat removal is stopped; and (3) continuously increasing the feeding amount of the oxygen, and removing heat when the hot-spot temperature is higher than 730 DEG C, so that the hot-spot temperature is kept in a range of 700-730 DEG C until the reaction is finished. According to the heat removal method, reaction heat can be effectively and rapidly removed, the temperature of a hot spot is reduced, and the heat removal method is used for removing heat of a methane oxidative coupling reaction furnace and is suitable for the condition that the filling amount of a catalyst is large and reaches 10 g or above.

Description

Technical Field

[0001] This invention belongs to the field of methane oxidative coupling to ethylene technology, specifically, it relates to a heat removal method and a reaction furnace for the preparation of C2 hydrocarbons by methane oxidative coupling. Background Technology

[0002] Natural gas is recognized worldwide as a clean energy source and one of the world's three major fossil fuels. It is widely used as industrial and domestic fuel. Natural gas is also a high-quality chemical raw material. It contains about 95% methane. With the gradual depletion of oil resources, natural gas will be the main carbon source for basic chemicals in the future. Therefore, the development and utilization of natural gas has received increasing attention worldwide.

[0003] Oxidative coupling of methane (OCM) is an important development direction in the comprehensive utilization of natural gas. Since Keller et al. first proposed the technology in 1982, it has been a focus of attention in the catalysis, chemical, and oil and gas industries. With the breakthroughs in shale gas in the United States, large quantities of previously difficult-to-extract methane have been extracted, and the chemical utilization of methane has once again attracted great attention from the industry. Among these advancements, research on oxidative coupling of methane, considered the most promising, has once again become a global research hotspot.

[0004] Oxidative coupling of methane generally requires high temperatures (>600℃) and is a strongly exothermic reaction. The hot spot effect generated during the reaction poses many challenges to scale-up and process flow. Currently, laboratory-scale OCM studies are typically small-scale, with catalyst loadings mostly ranging from 0.1 to 0.8 g. As the catalyst loading increases, the absolute amount of reaction increases, and the heat released increases accordingly. Due to the strong exothermic nature of the reaction, without effective heat removal measures, most of the heat is absorbed by the reactants, causing the catalyst bed temperature to rise too rapidly, resulting in excessively high hot spot temperatures and potentially causing runaway reactions.

[0005] Therefore, how to remove the heat generated by the reaction while maintaining the optimal C2 yield is the most pressing issue in the methane oxidative coupling process. Summary of the Invention

[0006] This invention aims to address one of the technical problems in related technologies to a certain extent, providing a reaction process for the oxidative coupling of methane to prepare olefins with a catalyst loading of 10g or more. The reaction process differs from general reaction processes in that, at the beginning of the reaction, the methane feed rate is fixed at a predetermined final value, and the oxygen feed rate is gradually increased. When the hot spot temperature exceeds 750℃, heat is removed to maintain the hot spot temperature at 700-730℃. Oxygen is then added again, and the hot spot temperature increases with the increase in oxygen feed. When the hot spot temperature is no longer between 700-730℃, heat is removed again to maintain the hot spot temperature at 700-730℃. This results in a final alkane-to-oxygen ratio of 2-4:1, with the hot spot temperature maintained at 700-730℃.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for removing heat from the methane oxidative coupling process to prepare C2 hydrocarbons, comprising the following steps:

[0008] (1) Methane and oxygen are introduced into the catalyst bed to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount makes the alkane-oxygen ratio 7-10:1.

[0009] (2) When the hot spot temperature exceeds 750℃, remove the heat and reduce the hot spot temperature to the range of 700-730℃, then stop removing the heat.

[0010] (3) Continue to increase the oxygen feed rate. When the hot spot temperature is higher than 730℃, remove the heat to keep the hot spot temperature in the range of 700-730℃ until the reaction is over.

[0011] A second aspect of the present invention provides a reactor for the preparation of C2 hydrocarbons by oxidative coupling of methane, for performing the heat removal method for the preparation of C2 hydrocarbons by oxidative coupling of methane, the reactor comprising a furnace body, a reaction tube inside the furnace body, a heat insulation layer between the furnace body and the reaction tube, and a catalyst bed disposed inside the reaction tube;

[0012] The furnace body is provided with an opening and closing part, and a freely detachable heat preservation section is provided near the opening and closing part of the furnace body.

[0013] A third aspect of the present invention provides a heat removal method using the aforementioned reactor, comprising the following steps:

[0014] (1) Methane and oxygen are introduced into the reaction chamber to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount makes the alkane-oxygen ratio 7-10:1.

[0015] (2) When the hot spot temperature exceeds 750℃, open the freely detachable insulation section to reduce the hot spot temperature to the range of 700-730℃, and then close the freely detachable insulation section.

[0016] (3) Continue to increase the oxygen feed rate. When the hot spot temperature is higher than 730℃, open the freely detachable heat preservation section to remove heat and keep the hot spot temperature in the range of 700-730℃ until the reaction ends.

[0017] The heat removal method of the present invention can effectively and quickly remove the heat of reaction and reduce the temperature of the hot spot. It is suitable for removing heat from the reactor of methane oxidative coupling, and is applicable to catalyst loading of up to 10g or more. It is easy to reduce the temperature of the hot spot and is easy to apply in large-scale production.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0020] Figure 1 A cross-sectional schematic diagram of the reactor for the preparation of C2 hydrocarbons by oxidative coupling of methane according to the present invention is shown.

[0021] Explanation of reference numerals in the attached figures

[0022] 1. Removable insulation section; 2. Opening / closing joint. Detailed Implementation

[0023] 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.

[0024] To achieve the above objectives, a first aspect of the present invention provides a method for removing heat from the methane oxidative coupling process to prepare C2 hydrocarbons, comprising the following steps:

[0025] (1) Methane and oxygen are introduced into the catalyst bed to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount is such that the alkane-oxygen ratio is maintained at 7-10:1.

[0026] (2) When the hot spot temperature exceeds 750℃, remove the heat and reduce the hot spot temperature to the range of 700-730℃, then stop removing the heat.

[0027] (3) Increase the oxygen feed rate to 20-100 mL / min. When the hot spot temperature is higher than 730℃, remove the heat to keep the hot spot temperature in the range of 700-730℃ until the reaction is over.

[0028] In this invention, uniform feeding means that the feed rate is fixed at the beginning of the reaction and is the final predetermined value.

[0029] According to the present invention, preferably, the amount of catalyst loaded in the catalyst bed is ≥10g.

[0030] According to the present invention, preferably, in step (2), after the hot spot temperature is reduced to the range of 700-730°C, it is stabilized for 10-20 minutes before the heat removal is stopped.

[0031] According to the present invention, preferably, the conditions for the catalytic reaction include: a reaction temperature of 600-720°C, more preferably 620-660°C, a reaction pressure of 0.001-0.05 MPa, and a gas hourly space velocity (GHSV) of 20000-100000 mL / (g·h) based on methane and oxygen.

[0032] In this invention, the reaction temperature is the temperature at the catalyst bed inlet, and the hot spot temperature is the highest temperature within the bed. The hot spot temperature cannot drop below 700°C, otherwise the reaction cannot proceed. Maintaining the hot spot temperature at 700-730°C achieves the optimal alkoxy ratio of 2-4, and with the hot spot temperature maintained at 700-730°C, the C2 yield reaches its optimal level.

[0033] In this invention, the unit "mL / (g·h)" refers to the total amount (mL) of methane and oxygen gas used relative to 1g of the catalyst over a time of 1h.

[0034] In this invention, all pressure refers to gauge pressure.

[0035] According to the present invention, preferably, in step (3), the final alkoxy ratio of methane to oxygen is 2-4:1.

[0036] According to the present invention, preferably, the C2 hydrocarbon is ethane and / or ethylene.

[0037] In this invention, the catalyst can be prepared by conventional methane oxidative coupling to produce a C2 hydrocarbon catalyst.

[0038] According to one specific embodiment of the present invention, the catalyst in the catalyst bed is a rare earth metal oxide and optional additives; the content of the additives is 0-20 wt% based on the total weight of the catalyst.

[0039] Preferably, the rare earth metal oxide is at least one of La2O3, CeO2 and Sm2O3; and the auxiliary agent is at least one of Li, Ba and Sr.

[0040] More preferably, the catalyst is prepared by a method comprising the following steps;

[0041] The catalyst is prepared by grinding rare earth metal oxides or rare earth metal oxide precursors and optional additives, then heating them in air to 380-420°C at a heating rate of 2-10°C / min and holding for 3-5 hours, then heating them to 780-820°C at a heating rate of 2-10°C / min and calcining for 3-5 hours.

[0042] In this invention, the fillers at both ends of the catalyst are inert materials. These inert materials only serve to support the catalyst and do not participate in the reaction. Preferably, the inert materials are silicon dioxide and / or alumina, with the silicon dioxide derived from quartz sand.

[0043] A second aspect of the present invention provides a reactor for the preparation of C2 hydrocarbons by oxidative coupling of methane, for performing the heat removal method for the preparation of C2 hydrocarbons by oxidative coupling of methane, the reactor comprising a furnace body, a reaction tube inside the furnace body, a heat insulation layer between the furnace body and the reaction tube, and a catalyst bed disposed inside the reaction tube;

[0044] The furnace body is provided with an opening and closing part, and a freely detachable heat preservation section is provided near the opening and closing part of the furnace body.

[0045] In this invention, the opening and closing part is used to put the reaction tube into the furnace body. The freely detachable heat preservation section can be opened and closed freely like a door. Opening it can effectively and quickly remove the reaction heat and reduce the hot spot temperature. Using it as a reaction furnace for methane oxidative coupling is suitable for catalyst loading of large amounts, such as 10g or more, and it is easy to reduce the hot spot temperature and easy to apply in large-scale production.

[0046] In this invention, the freely detachable insulation section has the same thickness as the insulation layer of other parts of the reactor, and there are no gaps between them, ensuring a tight fit.

[0047] According to the present invention, preferably, the freely detachable heat-insulating section covers 15-50% of the total length of the catalyst bed, more preferably 25-40%, and the width is 0.25-0.7 times the inner diameter of the reaction tube, more preferably 0.3-0.5 times.

[0048] In this invention, the total length of the catalyst bed refers to the total length of the catalyst bed along the direction of the reaction stream, and the width refers to the width of the insulation layer perpendicular to the direction of the reaction stream in the catalyst bed.

[0049] A third aspect of the present invention provides a heat removal method using the aforementioned reactor, comprising the following steps:

[0050] (1) Methane and oxygen are introduced into the reaction chamber to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount is such that the alkane-oxygen ratio is maintained at 7-10:1.

[0051] (2) When the hot spot temperature exceeds 750℃, open the freely detachable insulation section to reduce the hot spot temperature to the range of 700-730℃, and then close the freely detachable insulation section.

[0052] (3) Continue to increase the oxygen feed rate. When the hot spot temperature is higher than 730℃, open the freely detachable heat preservation section to remove heat, so that the hot spot temperature is kept in the range of 700-730℃ until the reaction ends.

[0053] According to the present invention, preferably, the hot spot temperature is reduced to the range of 700-730°C, stabilized for 10-20 minutes, and then the freely detachable heat preservation section is closed.

[0054] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0055] Preparation Example 1

[0056] Analytical-grade La2O3 was directly placed in a mortar and ground thoroughly at room temperature. Then, the temperature was raised to 400°C in air at a heating rate of 5°C / min and held for 4 hours. The temperature was then raised to 800°C at a heating rate of 5°C / min and calcined for 4 hours. The mixture was then allowed to cool naturally to room temperature to obtain the catalyst La2O3.

[0057] Preparation Example 2

[0058] Analytical grade Sm2O3 was directly placed in a mortar and ground thoroughly at room temperature. Then, the temperature was raised to 400°C in air at a heating rate of 5°C / min and held for 4 hours. The temperature was then raised to 800°C at a heating rate of 5°C / min and calcined for 4 hours. The mixture was then allowed to cool naturally to room temperature to obtain the catalyst Sm2O3.

[0059] The catalyst can be a pure rare earth metal oxide or a catalyst mainly composed of rare earth metal oxides, such as La2O3, CeO2, and Sm2O3. The promoter can be Li, Ba, or Sr, etc.

[0060] Preparation Example 3

[0061] Analytical grade CeO2 was directly placed in a mortar and ground thoroughly at room temperature. Then, it was heated to 400°C in air at a heating rate of 5°C / min and held for 4 hours. Next, it was heated to 800°C at a heating rate of 5°C / min and calcined for 4 hours. The mixture was then allowed to cool naturally to room temperature to obtain the catalyst CeO2.

[0062] Preparation Example 4

[0063] Analytical grade La2O3 and Ba in a mass ratio of 9:1 were directly placed in a mortar and ground thoroughly at room temperature. The mixture was then heated to 400°C in air at a heating rate of 5°C / min and held for 4 hours. The mixture was then heated to 800°C at a heating rate of 5°C / min and calcined for 4 hours. The mixture was then allowed to cool naturally to room temperature to obtain the catalyst Ba / La2O3.

[0064] Example 1

[0065] This embodiment provides a reaction furnace for the oxidative coupling of methane to prepare C2 hydrocarbons, such as Figure 1 As shown, the reactor includes a furnace body, a reaction tube inside the furnace body, an insulation layer between the furnace body and the reaction tube, and a catalyst bed disposed within the reaction tube. The furnace body has an opening / closing section, and a removable insulation section is disposed near the opening / closing section. The thickness of the insulation layer of this removable insulation section is the same as that of the insulation layers of other parts of the reactor, and they are tightly fitted together without gaps. The reaction tube has an inner diameter of 200 mm, an outer diameter of 250 mm, and a length of 900 mm. The insulation layer is 7 cm thick, the catalyst bed is 100 mm long, and the length and width of the removable insulation section covering the catalyst bed are 30 mm and 60 mm respectively. The catalyst is La2O3, and the loading amount is 10 g.

[0066] A method for removing heat from the oxidative coupling of methane to prepare C2 hydrocarbons includes the following steps: The reaction pressure is the pressure generated by the raw materials themselves, i.e., 0.05 MPa; the reaction temperature is 650 °C; the gas hourly space velocity (GHSV) for methane and oxygen is 15000 mL / (g·h); the initial methane feed rate is fixed at 1660 mL / min; the initial oxygen ratio is 8:1; after 1.5 hours of reaction, when the alkane-to-oxygen ratio reaches 4:1 and the hot spot temperature is 769 °C, the freely detachable insulation section is opened; after the hot spot temperature drops to 728 °C and stabilizes for 10 min, the freely detachable insulation section is closed again. The oxygen feed rate is then increased by 35 mL / min, and the operation is repeated as above. This achieves an alkane-to-oxygen ratio of 2:1, maintains the hot spot temperature at 720 °C, and optimizes the C2 yield. The reaction products are then collected.

[0067] Example 2

[0068] The difference between this implementation and Example 1 is that the inner diameter of the reaction tube is 200mm, the outer diameter is 250mm, the length is 900mm, the insulation layer thickness is 6cm, the catalyst bed length is 115mm, the length of the freely detachable insulation section covering the catalyst bed is 45mm, the width is 80mm, the catalyst is Sm2O3, and the loading amount is 12g.

[0069] A method for removing heat from the oxidative coupling of methane to prepare C2 hydrocarbons includes the following steps: The reaction pressure is the pressure generated by the raw materials themselves, i.e., 0.07 MPa; the reaction temperature is 680 °C; the gas hourly space velocity (GHSV) for the reaction (methane and oxygen) is 25000 mL / (g·h); the initial methane feed rate is fixed at 3330 mL / min; the initial oxygen ratio is 9:1; after 2 hours of reaction, when the alkane-oxygen ratio reaches 5:1 and the hot spot temperature is 756 °C, the freely detachable insulation section is opened; after the hot spot temperature drops to 724 °C and stabilizes for 10 min, the freely detachable insulation section is closed again. The oxygen feed rate is then increased by 50 mL / min, and the operation is repeated as above. This achieves an alkane-oxygen ratio of 3:1, maintains the hot spot temperature at 720 °C, and optimizes the C2 yield. The reaction products are then collected.

[0070] Example 3

[0071] The difference between this implementation and Example 1 is that the inner diameter of the reaction tube is 200mm, the outer diameter is 250mm, the length is 900mm, the insulation layer thickness is 8cm, the catalyst bed length is 100mm, the length of the freely detachable insulation section covering the catalyst bed is 25mm, the width is 100mm, the catalyst is CeO2, and the loading amount is 10g.

[0072] A method for removing heat from the oxidative coupling of methane to prepare C2 hydrocarbons includes the following steps: The reaction pressure is the pressure generated by the raw materials themselves, i.e., 0.04 MPa; the reaction temperature is 620 °C; the gas hourly space velocity (GHSV) for the reaction (methane and oxygen) is 10000 mL / (g·h); the initial methane feed rate is fixed at 1145 mL / min; the initial oxygen ratio is 7:1; after 1 hour of reaction, when the alkane-to-oxygen ratio reaches 4:1 and the hot spot temperature is 751 °C, the freely detachable insulation section is opened; after the hot spot temperature drops to 715 °C and stabilizes for 10 min, the freely detachable insulation section is closed again. The oxygen feed rate is then increased by 25 mL / min, and the operation is repeated as above. This achieves an alkane-to-oxygen ratio of 2.2:1, maintains the hot spot temperature at 715 °C, and optimizes the C2 yield. The reaction products are then collected.

[0073] Example 4

[0074] The difference between this implementation and Example 1 is that the inner diameter of the reaction tube is 200mm, the outer diameter is 250mm, the length is 900mm, the insulation layer thickness is 7.5cm, the catalyst bed length is 102mm, the length of the freely detachable insulation section covering the catalyst bed is 35mm, the width is 90mm, the catalyst is Ba / La2O3, and the loading amount is 10g.

[0075] A method for removing heat from the oxidative coupling of methane to prepare C2 hydrocarbons includes the following steps: The reaction pressure is the pressure generated by the raw materials themselves, i.e., 0.05 MPa; the reaction temperature is 700 °C; the gas hourly space velocity (GHSV) for the reaction (methane and oxygen) is 20000 mL / (g·h); the initial methane feed rate is fixed at 2380 mL / min; the initial oxygen ratio is 9:1; after 1.5 hours of reaction, when the alkane-to-oxygen ratio reaches 4:1 and the hot spot temperature is 760 °C, the freely detachable insulation section is opened; after the hot spot temperature drops to 718 °C and stabilizes for 10 min, the freely detachable insulation section is closed again. The oxygen feed rate is then increased by 60 mL / min, and the operation is repeated as above. This achieves an alkane-to-oxygen ratio of 2.5:1, maintains the hot spot temperature at 720 °C, and optimizes the C2 yield. The reaction products are then collected.

[0076] Comparative Example 1

[0077] The difference between this comparative example and the embodiment is that the insulation layer of the reactor is a single, integral unit that cannot be freely opened or closed. The reaction for the oxidative coupling of methane to C2 hydrocarbons was carried out according to the method of Example 1, except that the alkane-to-oxygen ratio reached a preset value of 2:1, at which point the catalyst bed hot spot temperature was 767°C.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 1 is that, during the reaction process, the heat was not gradually removed until the hot spot temperature dropped to a certain value before continuing the oxygenation reaction. Instead, the alkoxy feed rate was directly preset to the final value of 2.2:1, the hot spot temperature was raised to 782°C, and then the freely detachable heat preservation section was opened to remove heat to 720°C.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that the freely detachable heat preservation section was opened for heat removal from the beginning of the reaction.

[0082] Test Example 1

[0083] The components of the reaction products obtained in the examples and comparative examples were analyzed using a gas chromatograph (Gas Chromatograph, Model 7890A, Agilent Technologies). The products were determined using a dual-detection-channel, three-valve, four-column system, with the FID detector connected to an alumina column for analyzing CH4, C2H6, C2H4, C3H8, C3H6, and C4H. 10 Components such as C4H8 and CnHm are detected by TCD detectors, which are mainly used to detect CO, CO2, N2, O2, and CH4.

[0084] The calculation methods for methane conversion rate, etc., are as follows:

[0085] Methane conversion rate = Amount of methane consumed in the reaction / Initial amount of methane × 100%

[0086] Ethylene selectivity = Amount of methane consumed to produce ethylene / Total methane consumption × 100%

[0087] Ethane selectivity = Amount of methane consumed to produce ethane / Total methane consumption × 100%

[0088] C2 hydrocarbon selectivity = ethane selectivity + ethylene selectivity

[0089] CO x (CO + CO2) selectivity = (Amount of methane consumed by the combined generation of CO and CO2) / (Total methane consumption) × 100%

[0090] C2 hydrocarbon yield = methane conversion rate × (ethane selectivity + ethylene selectivity)

[0091] The results are shown in Table 1.

[0092] Table 1

[0093]

[0094] As can be seen from the table above, the process and method of this application for the preparation of C2 hydrocarbons by oxidative coupling of methane reduces the hot spot temperature, inhibits the deep oxidation of methane, reduces the occurrence of side reactions, and the yield of C2 hydrocarbons is relatively high.

[0095] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0096] 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.

Claims

1. A method for removing heat from the oxidative coupling of methane to prepare C2 hydrocarbons, characterized in that, Includes the following steps: (1) Methane and oxygen are introduced into the catalyst bed to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount makes the alkane-oxygen ratio 7-10:

1. (2) When the hot spot temperature exceeds 750℃, remove the heat and reduce the hot spot temperature to the range of 700-730℃, then stop removing the heat. (3) Continue to increase the oxygen feed rate. When the hot spot temperature is higher than 730℃, remove the heat to keep the hot spot temperature in the range of 700-730℃ until the reaction ends.

2. The heat removal method according to claim 1, wherein, The catalyst loading in the catalyst bed is ≥10g.

3. The heat removal method according to claim 1, wherein, In step (2), after the hot spot temperature is reduced to the range of 700-730℃, it is stabilized for 5-20 minutes before the heat removal is stopped.

4. The heat removal method according to claim 1, wherein, The conditions for the catalytic reaction include: a reaction temperature of 600-720℃, preferably 620-660℃, a reaction pressure of 0.001-0.05MPa, and a gas hourly space velocity (GHSV) of 20000-100000mL / (g·h) for methane and oxygen.

5. The heat removal method according to claim 1, wherein, In step (3), the final alkoxy ratio of methane to oxygen is 2-4:

1.

6. The heat removal method according to claim 1, wherein, The C2 hydrocarbon is ethane and / or ethylene.

7. A reactor for the oxidative coupling of methane to prepare C2 hydrocarbons, used to perform the heat removal method for the oxidative coupling of methane to prepare C2 hydrocarbons according to any one of claims 1-6, characterized in that, The reactor includes a furnace body, a reaction tube inside the furnace body, an insulation layer between the furnace body and the reaction tube, and a catalyst bed disposed inside the reaction tube. The furnace body is provided with an opening and closing part, and a freely detachable heat preservation section is provided near the opening and closing part of the furnace body.

8. The reactor according to claim 7, wherein, The freely detachable insulation section has the same thickness as the insulation layer of other parts of the reactor and is tightly bonded to the insulation layer of other parts of the reactor.

9. The reactor according to claim 7, wherein, The freely detachable heat-insulating section covers 15-50% of the total length of the catalyst bed, preferably 25-40%, and its width is 0.25-0.7 times the inner diameter of the reaction tube, preferably 0.3-0.5 times.

10. A method for removing heat from a reactor according to any one of claims 7-9, characterized in that, Includes the following steps: (1) Methane and oxygen are introduced into the reaction chamber to contact the catalyst for catalytic reaction. The methane is fed at a constant rate, and the oxygen is fed gradually. The initial feed amount is such that the alkane-oxygen ratio is maintained at 7-10:

1. (2) When the hot spot temperature exceeds 750℃, open the freely detachable insulation section to reduce the hot spot temperature to the range of 700-730℃, and close the freely detachable insulation section. (3) Continue to increase the oxygen feed rate. When the hot spot temperature is higher than 730℃, open the freely detachable heat preservation section to remove heat, so that the hot spot temperature is kept in the range of 700-730℃ until the reaction ends.

11. The heat removal method using the reactor according to claim 10, wherein, Reduce the hot spot temperature to 700-730℃ and stabilize it for 10-20 minutes before closing the removable insulation section.

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