Process for the dry reforming of methane with carbon dioxide to syngas

Abstract

The present application relates to the technical fields of chemical synthesis, and discloses a method for preparing synthesis gas by dry reforming of methane and carbon dioxide, which comprises the following steps: (1) contacting raw materials containing methane and carbon dioxide with a catalyst to perform a dry reforming reaction, so as to obtain a product stream containing synthesis gas; (2) regenerating part of the catalyst in step (1) as catalyst A to obtain regenerated catalyst, reducing the regenerated catalyst to obtain reduced catalyst, and returning the reduced catalyst to the dry reforming reaction; and (3) heating part of the catalyst in step (1) as catalyst B and returning the heated catalyst B to the dry reforming reaction. The method can be used in the production of synthesis gas, can effectively improve the conversion rate of methane and carbon dioxide, can greatly reduce the production of carbon deposition in the reaction, and has the advantages of long catalyst activity time and long continuous operation time of the device.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to a method for producing synthesis gas by dry reforming methane with carbon dioxide. Background Technology

[0002] Carbon dioxide and methane are not only major greenhouse gases but also important carbon-containing resources. How to effectively utilize carbon dioxide has attracted widespread attention worldwide. The reforming of methane and carbon dioxide to produce syngas combines the comprehensive utilization of methane with the resource utilization of carbon dioxide, providing a technological route for the large-scale utilization of carbon and hydrogen sources. This aligns with the requirements of green chemical engineering, and the development of efficient carbon dioxide-methane reforming technology is of great significance for achieving carbon emission reduction in fossil energy utilization processes.

[0003] CN104587912A discloses a fluidized bed reactor and a fluidized bed reaction apparatus, as well as a method for methane steam reforming. A catalytically active foamed metal plate is placed in the reaction zone of the reactor. This foamed metal plate exhibits catalytic activity for the methane steam reforming reaction, and the catalyst does not require frequent regeneration along with the adsorbent, reducing energy consumption in the regeneration process and avoiding unnecessary degradation of catalyst activity. However, the methane steam reforming process for producing syngas has disadvantages such as limited operational flexibility, high energy consumption, large and complex equipment, and high operating costs. Furthermore, the H2 / CO ratio (molar ratio ≥ 3) in the syngas produced by methane steam reforming is too high, making it unsuitable as a feedstock for carbonyl synthesis and Fischer-Tropsch synthesis.

[0004] CN117049474A discloses a method for catalyzing the dry reforming reaction of methane and carbon dioxide using a nickel-based catalyst. The method employs electrostatic adsorption deposition to disperse active nickel species on a CaAl2O4 support. The catalyst can operate stably for more than 1100 hours at 750℃, and there is no obvious deactivation, agglomeration, or carbon deposition.

[0005] CN116510741A discloses an anti-coking methane dry reforming catalyst and its preparation and application method. It uses ZrO2-MgO as a mesoporous support to support a bimetallic Ni-Mo catalyst, improving the bonding strength between the active component and the support, and enhancing the catalyst's anti-coking performance. This patent uses a fixed-bed reactor and does not provide reaction data for methane-carbon dioxide dry reforming under pressure. Since increased pressure is very detrimental to the reaction, the adverse effects of pressure must be addressed during engineering scale-up and application.

[0006] Conventional fixed-bed methane-carbon dioxide reforming technology suffers from problems such as poor long-term catalyst stability, easy catalyst deactivation due to carbon buildup, and easy sintering of active metals, which are significant factors restricting its large-scale application. Therefore, it is necessary to develop a method for producing syngas that can effectively solve the problems existing in methane-carbon dioxide reforming technology. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low conversion rate under pressure, short catalyst activity time, and short continuous operation time of existing methane-carbon dioxide dry reforming technology for producing syngas. This invention provides a method for producing syngas through methane-carbon dioxide dry reforming. This method, when used in syngas production, can effectively improve the conversion rate of methane and carbon dioxide, significantly reduce the generation of reaction coke, and has the advantages of long catalyst activity time and long continuous operation time of the device.

[0008] To achieve the above objectives, the present invention provides a method for producing syngas from methane via dry reforming with carbon dioxide, wherein the method includes:

[0009] (1) The raw materials containing methane and carbon dioxide are contacted with a catalyst to carry out a dry reforming reaction to obtain a product stream containing syngas.

[0010] (2) Part of the catalyst in step (1) is used as catalyst A to regenerate the regenerated catalyst, which is then returned to the dry reforming reaction;

[0011] (3) Part of the catalyst in step (1) is used as catalyst B and then returned to the dry reforming reaction after heating.

[0012] Preferably, in step (2), the circulation rate of catalyst A and the methane feed rate follow the formula F. A =a×G,F A Where A is the catalyst A circulation rate, a is a coefficient with a value ranging from 0.05 to 0.5, preferably from 0.1 to 0.3, and G is the methane feed flow rate.

[0013] Preferably, the regeneration conditions include: the absolute value of the temperature difference between the regeneration temperature and the dry reforming reaction temperature is not greater than 100°C, and more preferably not greater than 70°C.

[0014] Preferably, the circulation rate of catalyst B is related to the methane feed rate by formula F. B ×(t 加热 -t 反应 )=b×G,F B The amount of catalyst B circulating is t. 加热 The temperature (t) after catalyst B is heated is the numerical value. 反应 denoted as the dry reforming reaction temperature, b as a coefficient ranging from 300 to 1200, preferably 400 to 800, and G as the methane feed flow rate.

[0015] The beneficial effects achieved through the above technical solution are as follows:

[0016] In this invention, the method employs circulating fluidized bed technology, which combines reaction and regeneration functions. It is used in the production of syngas and yields high syngas. It has advantages such as rapid catalyst regeneration through coking and balanced heat within the bed, effectively improving the conversion rate of methane and carbon dioxide, significantly reducing the generation of reaction coke, and providing long catalyst activity time and long continuous operation time of the device, enabling long-term stable operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fluidized bed reaction system of the method of the present invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 1- Fluidized bed reactor; 2- Reactant feed inlet; 3- Production line

[0020] 4-Conveying medium inlet; 5-Regenerating medium inlet; 6-Regenerator

[0021] 7-Regenerator Cyclone Separator 8-Regenerator Outlet 9-Degassing Tank

[0022] 10-Degassing medium inlet; 11-Regeneration pipeline; 12-Reduction tank

[0023] 13-Reduction medium inlet; 14-Reduction pipeline; 15-Reactor cyclone separator

[0024] 16-Reactor outlet; 17-Quick quench chamber; 18-Quick quench medium inlet

[0025] 19-Cooler 20-Product Gas Outlet 21-Heater

[0026] 22-Heating medium 23-Heating circulation inclined tube 24-Heating return inclined tube Detailed Implementation

[0027] 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.

[0028] This invention provides a method for producing syngas from methane via dry reforming with carbon dioxide, wherein the method includes:

[0029] (1) The raw materials containing methane and carbon dioxide are contacted with a catalyst to carry out a dry reforming reaction to obtain a product stream containing syngas.

[0030] (2) Part of the catalyst in step (1) is used as catalyst A to regenerate the regenerated catalyst, which is then returned to the dry reforming reaction;

[0031] (3) Part of the catalyst in step (1) is used as catalyst B and then returned to the dry reforming reaction after heating.

[0032] In this invention, the dry reforming reaction of methane and carbon dioxide inevitably produces coke deposits on the catalyst. As the coke deposits increase, the catalyst activity decreases, requiring timely removal of the coke deposits and catalyst regeneration to maintain catalyst activity. The method employs circulating fluidized bed technology, which combines reaction and regeneration functions. It achieves high syngas yield in syngas production and has advantages such as rapid catalyst regeneration through coking and balanced heat within the bed. It can effectively improve the conversion rate of methane and carbon dioxide, significantly increase the total syngas yield, and has a long catalyst activity time and long continuous operation time, enabling long-term stable operation.

[0033] In this invention, the composition and source of the raw materials containing methane and carbon dioxide are not particularly limited. Those skilled in the art can adapt the molar ratio of methane to carbon dioxide in the raw materials containing methane and carbon dioxide according to the dry reforming reaction.

[0034] According to the present invention, preferably, the molar ratio of methane to carbon dioxide in the raw material containing methane and carbon dioxide is 0.6-1.2:1, for example 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, or any range between the two, preferably 0.8-1.1:1.

[0035] In this invention, the reaction conditions for the dry reforming reaction are not particularly limited and are the conventional methane-carbon dioxide dry reforming reaction conditions in the art. According to the present invention, preferably, the reaction conditions for the dry reforming reaction include: a reaction temperature of 600-900℃, preferably 700-850℃; a reaction pressure of 0-2 MPa, preferably 0.1-0.5 MPa; and a total mass hourly space velocity (MHV) of 0.1-10 h⁻¹. -1 Preferably 0.5-5h -1 .

[0036] In this invention, the reaction system used in the method is not particularly limited, and those skilled in the art can choose a suitable reaction system. Preferably, the method is carried out in a fluidized bed reaction system. More preferably, the reaction system includes: a fluidized bed reactor, a regenerator, a reduction tank, and a heater, wherein the dry reforming reaction is carried out in the fluidized bed reactor.

[0037] In this invention, preferably, the bottom of the fluidized bed reactor is provided with a raw material inlet for introducing the raw material containing methane and carbon dioxide.

[0038] According to the present invention, preferably, the catalyst comprises an active metal and a support. In this invention, the type and source of the catalyst are not particularly limited; it can be commercially available or prepared using existing methods. The size and shape of the catalyst are not particularly limited; those skilled in the art can adjust the size and shape of the catalyst according to the structural adaptability to the fluidized bed reactor.

[0039] According to the present invention, preferably, the active metal is selected from at least one of Fe, Co, Ni, Pd, and Pt, and more preferably Ni. In the present invention, a catalyst containing the above-mentioned active metal is used in a dry reforming reaction. The catalyst exhibits good catalytic activity and can improve the reaction efficiency of converting methane and carbon dioxide into gas containing carbon monoxide and hydrogen.

[0040] According to the present invention, preferably, the support is selected from at least one of Al2O3, SiO2, MgO, TiO2, ZrO2 and ZnO, and more preferably Al2O3 and / or MgO.

[0041] According to the present invention, preferably, the content of active metal elements in the catalyst, based on the total mass of the catalyst, is 1-20 wt%, for example, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, or any range between the two, preferably 4-15 wt%. In the present invention, the content of active metals in the catalyst is determined by X-ray fluorescence spectrometry (XRF).

[0042] In this invention, preferably, the reaction system further includes a separator installed at the top of the fluidized bed reactor to remove catalyst entrained in the product stream containing syngas, preventing catalyst from flowing out of the reactor. Preferably, the separator is a cyclone separator.

[0043] According to the present invention, preferably, step (1) further includes mixing the product stream containing syngas with a quenching medium to obtain quenched syngas.

[0044] According to the present invention, preferably, the method further includes cooling the quenched syngas to obtain cooled syngas.

[0045] In this invention, preferably, the reaction system further includes a cooler. The quenched synthesis gas enters the cooler for further cooling. In this invention, the cooler is provided with a product gas outlet for discharging the cooled product from the reaction system into subsequent processes.

[0046] In this invention, the equipment for performing the quenching is not particularly limited, as long as it can mix the quenching medium with the product stream containing syngas. According to a preferred embodiment of the present invention, the reaction system further includes a quenching chamber and a quenching medium inlet, through which the quenching medium is introduced and quenching is performed in the quenching chamber.

[0047] In this invention, preferably, the top of the fluidized bed reactor is also provided with a reactor outlet, which is connected to the quench chamber, so that the separated product stream containing syngas is sent into the quench chamber.

[0048] According to the present invention, preferably, the temperature of the quenched syngas is not higher than 560°C, and more preferably 280-510°C. In the present invention, the temperature of the syngas product at the outlet of the fluidized bed reactor is relatively high, and the carbon monoxide in it is prone to disproportionation reaction at high temperature to generate coke. In order to avoid carbon monoxide loss and coke blockage of pipelines, it is necessary to rapidly quench and cool the product gas.

[0049] According to the present invention, preferably, the quenching medium is water and / or cooled syngas, more preferably cooled syngas. In this invention, those skilled in the art can adjust the amount of quenching medium used based on the temperature adaptability of the syngas-containing product stream.

[0050] In this invention, preferably, in step (2), the catalyst A is lifted to the regenerator via a conveying medium, wherein the conveying medium is nitrogen and / or carbon dioxide.

[0051] In this invention, preferably, the reaction system further includes a regenerator pipeline and a transport medium inlet. The bottom of the fluidized bed reactor is connected to the regenerator pipeline. The catalyst A flows out through the regenerator pipeline, and the transport medium introduced through the transport medium inlet is lifted to the regenerator.

[0052] According to the present invention, preferably, in step (2), the circulation rate of catalyst A and the methane feed rate follow the formula F. A =a×G,F A Let be the catalyst A circulation rate, 'a' be a coefficient ranging from 0.05 to 0.5, for example, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, or any range between the two, preferably 0.1 to 0.3, and 'G' be the methane feed rate. The methane feed rate is the mass flow rate of methane fed per unit time in the raw material. Those skilled in the art can adjust the methane feed rate adaptively according to the size of the reaction system.

[0053] In this invention, preferably, the circulation rate of catalyst A is adjusted according to the methane feed flow rate, the coking rate of the reaction, and the coke content of the catalyst in the reactor. This allows for timely replenishment of the highly catalytically active catalyst to catalyze the dry reforming reaction of methane and carbon dioxide, ensuring a high reactant conversion rate and syngas yield in the dry reforming reaction. It also avoids excessive coking of the catalyst leading to a decrease in activity, thus extending the catalyst activity time and consequently extending the operating time of the reaction system.

[0054] According to the present invention, preferably, the regeneration conditions include: a regeneration temperature of 600-900℃, more preferably 700-850℃; and a regeneration pressure of 0-2MPa, more preferably 0.1-0.5MPa.

[0055] According to the present invention, preferably, the absolute value of the temperature difference between the regeneration temperature in step (2) and the dry reforming reaction temperature in step (1) is not greater than 100°C, for example, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or any range between the two, preferably not greater than 70°C.

[0056] In this invention, controlling the temperature difference between the regeneration temperature and the dry reforming reaction temperature to meet the above-mentioned range can improve the yield of syngas from the dry reforming reaction while saving system energy consumption. If the regeneration temperature is too high, the energy consumption of the regeneration system will be high. If the temperature difference between the regeneration temperature and the reaction temperature is too large, it will cause a serious imbalance in the heat of the catalyst in the reactor when catalyst A is recycled back to the reactor, thus affecting the reaction conversion rate and the total yield of syngas.

[0057] In this invention, preferably, the regeneration is carried out in the presence of a regeneration medium to obtain a regenerated catalyst, wherein the regeneration medium is an oxygen-containing gas, preferably air.

[0058] In this invention, preferably, the reaction system includes a regeneration medium inlet, through which a regeneration medium is introduced to regenerate catalyst A in a regenerator.

[0059] According to a preferred embodiment of the present invention, a regenerator separator, preferably a regenerator cyclone separator, is provided at the top of the regenerator for separating the regeneration catalyst and the reaction products of the regeneration medium. Preferably, a regenerator outlet is also provided at the top of the regenerator for discharging the separated reaction products of the regeneration medium from the regenerator.

[0060] According to the present invention, preferably, the method in step (2) further includes reducing the regenerated catalyst to obtain a reduced catalyst. In the present invention, reducing the regenerated catalyst can improve the conversion rate of methane and carbon dioxide in the dry reforming reaction.

[0061] According to the present invention, preferably, the reduction conditions include: in the presence of a reducing medium, the mass hourly space velocity of the reducing medium is 0.001-1 h⁻¹. -1 Preferably, it is 0.01-0.5h. -1 The reduction temperature is 600-900℃, preferably 700-850℃; the reduction pressure is 0-2MPa, preferably 0.1-0.5MPa.

[0062] According to the present invention, preferably, the reducing medium is hydrogen.

[0063] In this invention, preferably, the reaction system further includes a reduction vessel and a reduction medium inlet. According to a preferred embodiment of the invention, a reduction medium is introduced through the reduction medium inlet, and in the presence of the reduction medium, the degassed product is reduced in the reduction vessel to obtain a reduction catalyst.

[0064] In this invention, preferably, the reaction system further includes a degassing tank and a degassing medium inlet. The degassing tank is connected to a regenerator via a pipeline. A regenerated catalyst is introduced into the degassing tank, and a degassing medium is introduced through the degassing medium inlet. The regenerated catalyst is degassed in the degassing tank to obtain a degassed product. In this invention, the degassing medium is nitrogen and / or carbon dioxide.

[0065] In this invention, preferably, a degassing tank is provided to remove the oxygen introduced during regeneration, thereby reducing the waste of hydrogen during the reduction process, improving the reduction effect of the regenerated catalyst, obtaining a reduction catalyst with higher catalytic activity, and avoiding the safety risks caused by oxygen entrainment into the reduction tank and reactor.

[0066] In this invention, preferably, the reaction system further includes a regeneration pipeline and a reduction pipeline, wherein the regeneration pipeline is used to transport the degassed product to the reduction tank, and the reduction pipeline is used to transport the reduction catalyst to the fluidized bed reactor.

[0067] In this invention, preferably, the regenerated catalyst is reduced by a reducing medium to obtain a reduced catalyst, which can improve the catalyst activity in the dry reforming reaction to produce syngas. After the regenerated catalyst is reduced, the conversion rate of methane and carbon dioxide and the total yield of syngas are higher than when the regenerated catalyst is not reduced.

[0068] According to the present invention, the circulation rate of catalyst B can be adaptively adjusted by those skilled in the art based on the feed rate and the dry reforming reaction conditions. Preferably, the circulation rate of catalyst B and the methane feed rate follow the formula F. B ×(t 加热 -t 反应 )=b×G,F B The amount of catalyst B circulating is t. 加热 The temperature (t) after catalyst B is heated is the numerical value.反应 is the dry reforming reaction temperature, b is a coefficient with a value ranging from 300 to 1200, such as 300, 400, 500, 600, 700, 800, 900, 1000, 1200, or any range between the two, preferably 400-800, and G is the methane feed flow rate.

[0069] In this invention, part of the catalyst in step (1) is heated and returned to the dry reforming reactor as catalyst B. Since the dry reforming reaction of methane and carbon dioxide is a strongly endothermic reaction, the temperature in the reactor will drop as the reaction proceeds. By heating part of the catalyst and recycling it back to the reactor, heat can be provided for the dry reforming reaction, maintaining the catalyst temperature in the fluidized bed reactor within a suitable range for the dry reforming reaction, and improving the efficiency of the dry reforming reaction.

[0070] In this invention, preferably, the heating in step (3) is performed in a heater.

[0071] According to the present invention, preferably, the temperature difference between the heated catalyst B and the dry reforming reaction temperature in step (3) is not less than 30°C, and more preferably 50-100°C. In the present invention, the heated catalyst B is at a higher temperature than the dry reforming reaction temperature, supplementing heat to maintain the catalyst bed temperature and providing heat for the dry reforming reaction. If the temperature difference is too small, it will increase the circulation of catalyst B, increasing unnecessary energy and material consumption; if the temperature difference is too large, the circulation of catalyst B back to the reactor will cause a serious imbalance in the catalyst heat in the reactor, thus affecting the reaction conversion rate and the total yield of syngas. Therefore, controlling an appropriate temperature difference can optimize the process operation of the reaction system.

[0072] In this invention, preferably, the reaction system further includes a heating circulation inclined tube and a heating return inclined tube, through which catalyst B is transferred between the heater and the fluidized bed reactor and heated under the action of the heating medium.

[0073] According to a preferred embodiment of the present invention, in Figure 1 The reaction system shown performs dry reforming of methane and carbon dioxide to produce syngas. The raw materials containing methane and carbon dioxide are fed into the fluidized bed reactor 1 through the raw material inlet 2 and contacted with the catalyst for dry reforming. The resulting product stream containing syngas is separated by a reactor cyclone separator 15 at the top of the fluidized bed reactor 1 to remove the catalyst and then flows out through the reactor outlet 16. It is then mixed with the quench medium introduced by the quench medium inlet 18 in the quench chamber 17 and quenched before entering the cooler 19. After cooling, it is sent to the subsequent process through the product gas outlet 20.

[0074] In the fluidized bed reactor 1, a portion of the catalyst, known as catalyst A, flows out from the bottom of the fluidized bed reactor 1 via the regeneration pipeline 3. It is then lifted to the regenerator 6 by the conveying medium introduced through the conveying medium inlet 4. The regeneration medium is introduced through the regeneration medium inlet 5 to contact and regenerate catalyst A. The regenerated catalyst and the reaction product of the regeneration medium are separated by the cyclone separator 7 in the regenerator. The reaction product of the regeneration medium is discharged through the regenerator outlet 8. The regenerated catalyst is sent to the degassing tank 9 and degassed by the degassing medium introduced through the degassing medium inlet 10. It is then sent to the reduction tank 12 via the regeneration pipeline 11. The regenerated catalyst is reduced by the reducing medium introduced through the reduction medium inlet 13 to obtain the reduced catalyst. The reduced catalyst is returned to the fluidized bed reactor 1 via the reduction pipeline 14.

[0075] In the fluidized bed reactor 1, part of the catalyst, as catalyst B, is sent to the heater 21 via the heating circulation inclined tube 23. After being heated by the heating medium 22, it is returned to the fluidized bed reactor 1 via the heating return inclined tube 24.

[0076] In this invention, preferably, the dry reforming of methane and carbon dioxide to produce syngas is carried out in the above-mentioned reaction system. The circulating fluidized bed reaction technology combines the reaction and catalyst regeneration, which can quickly decoke and regenerate the catalyst to obtain a catalyst with high catalytic activity for the dry reforming reaction. At the same time, the catalyst is heated to supplement the heat of the fluidized bed reactor, maintain the catalyst bed temperature in the reactor, and ensure that the dry reforming reaction is carried out at a suitable temperature, thereby improving the yield of syngas and the conversion rate of methane and carbon dioxide.

[0077] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0078] Example 1

[0079] exist Figure 1 The reaction system shown is used to produce synthesis gas from methane by dry reforming with carbon dioxide according to the conditions shown in Table 1.

[0080] (1) The raw materials containing methane and carbon dioxide are fed into the fluidized bed reactor 1 through the raw material inlet 2 and contacted with the catalyst to carry out dry reforming reaction. The product stream containing syngas is obtained. After the catalyst is removed by the reactor cyclone separator 15 at the top of the fluidized bed reactor 1, it flows out through the reactor outlet 16. It is mixed with the quench medium introduced by the quench medium inlet 18 in the quench chamber 17 and quenched to a temperature of 350°C before entering the cooler 19. After cooling, it goes to the subsequent process through the product gas outlet 20.

[0081] (2) In the fluidized bed reactor 1, a portion of the catalyst, as catalyst A, flows out from the bottom of the fluidized bed reactor 1 via the regeneration pipeline 3. It is then lifted to the regenerator 6 by the conveying medium introduced through the conveying medium inlet 4. The regeneration medium is introduced through the regeneration medium inlet 5 to contact and regenerate catalyst A. The regenerated catalyst and the reaction product of the regeneration medium are separated by the regenerator cyclone separator 7. The reaction product of the regeneration medium is discharged through the regenerator outlet 8. The regenerated catalyst is sent to the degassing tank 9 and degassed by the degassing medium introduced through the degassing medium inlet 10. After degassing, it is sent to the reduction tank 12 via the regeneration pipeline 11. The regeneration catalyst is reduced by the reducing medium introduced through the reduction medium inlet 13 to obtain the reduced catalyst. The reduced catalyst is returned to the fluidized bed reactor 1 via the reduction pipeline 14. The circulation rate of catalyst A is controlled to be F. A =6kg / h (a=0.2, G=30kg / h).

[0082] (3) In the fluidized bed reactor 1, a portion of the catalyst, as catalyst B, is fed into the heater 21 via the heating circulation inclined tube 23. After being heated by the heating medium 22, it is returned to the fluidized bed reactor 1 via the heating return inclined tube 24. The circulation rate of catalyst B is controlled to be F. B =257kg / h (b=600, G=30kg / h, (t 加热 -t 反应 The value is 70).

[0083] Examples 2-6

[0084] exist Figure 1 The reaction system shown is used to produce synthesis gas from methane by dry reforming with carbon dioxide under the conditions shown in Table 1.

[0085] Example 7

[0086] Syngas was produced by dry reforming according to the method of Example 1, except that the circulation rate of catalyst A in step (2) was adjusted to 2 kg / h (a = 0.067, G = 30 kg / h), and other conditions were the same as in Example 1.

[0087] Example 8

[0088] Syngas was produced by dry reforming according to the method in Example 1, except that the circulation rate of catalyst B in step (3) was adjusted to 128 kg / h (b = 300, G = 30 kg / h, (t) 加热 -t 反应 The value of ) is 70), and other conditions are the same as in Example 1.

[0089] Example 9

[0090] Syngas was produced by dry reforming according to the method of Example 1, except that the regeneration temperature in step (2) was adjusted to 730°C and the absolute value of the temperature difference between the regeneration temperature and the dry reforming reaction temperature was 100°C. Other conditions were the same as in Example 1.

[0091] Example 10

[0092] Syngas was produced by dry reforming according to the method of Example 1, except that the temperature difference between the catalyst B after heating by the heater and the catalyst temperature in the reactor in step (3) was adjusted to 30°C, and other conditions were the same as in Example 1.

[0093] Example 11

[0094] Syngas was produced by dry reforming according to the method of Example 1, except that the reaction system did not have a reduction tank, and other conditions were the same as in Example 1.

[0095] Comparative Example 1

[0096] Syngas was produced by dry reforming according to the method of Example 1, except that the active metal of the catalyst was Zr, and other conditions were the same as in Example 1.

[0097] Comparative Example 2

[0098] Syngas was produced by dry reforming according to the method of Example 1, except that the circulation rate of catalyst A was 0, that is, the catalyst was not regenerated, and other conditions were the same as in Example 1.

[0099] Table 1 shows the process parameters for the dry reforming of methane and carbon dioxide to produce syngas in the embodiments and comparative examples of the present invention, including the reaction, catalyst, regeneration, and reduction.

[0100] Table 1

[0101]

[0102]

[0103] In this invention, methane conversion rate = (G1*C) 1甲烷 -G2*C 2甲烷 ) / (G1*C 1甲烷 )*100%;

[0104] Carbon dioxide conversion rate = (G1*C) 1二氧化碳 -G2*C 2二氧化碳 ) / (G1*C 1二氧化碳 )*100%;

[0105] Syngas yield = (G2*C) 2氢气 +G2*C 2一氧化碳 ) / (G1*C 1甲烷 +G1*C 1二氧化碳)*100%;

[0106] G1 is the feed gas flow rate, in kg / h; G2 is the product gas flow rate, in kg / h. 1甲烷 The mass percentage of methane in the feed gas, in %; C 1二氧化碳 The mass percentage of carbon dioxide in the feed gas, in %; C 2甲烷 The percentage of methane by mass in the product gas, in %; C 2二氧化碳 The percentage of carbon dioxide by mass in the product gas, in %; C 2氢气 The mass percentage of hydrogen in the product gas, in %; C 2一氧化碳 The percentage of carbon monoxide in the product gas, expressed in %.

[0107] Table 2 shows the reaction results of methane-carbon dioxide dry reforming to syngas after continuous operation for 720 h in the embodiments and comparative examples of the present invention.

[0108] Table 2

[0109] Methane conversion rate, % Carbon dioxide conversion rate, % Syngas yield, % Example 1 93.5 94.7 91.2 Example 2 91.3 96.1 90.1 Example 3 76.6 79.2 75.1 Example 4 83.0 80.1 76.6 Example 5 50.6 45.7 47.8 Example 6 80.2 87.5 82.1 Example 7 80.9 82.3 77.2 Example 8 83.9 85.1 80.7 Example 9 85.7 88.2 83.3 Example 10 77.1 79.3 75.0 Example 11 92.1 92.9 89.2 Comparative Example 1 55.0 57.7 49.1 Comparative Example 2 1.3 0.4 0.2

[0110] As can be seen from the results in Tables 1 and 2, the embodiments using the continuous reaction regeneration technology of the present invention have significantly better effects in terms of high methane conversion rate, high carbon dioxide conversion rate, and high syngas yield.

[0111] 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 method for producing syngas by dry reforming methane with carbon dioxide, characterized in that, The method includes: (1) The raw materials containing methane and carbon dioxide are contacted with a catalyst to carry out a dry reforming reaction to obtain a product stream containing syngas. (2) Part of the catalyst in step (1) is used as catalyst A to regenerate the regenerated catalyst, which is then returned to the dry reforming reaction; (3) Part of the catalyst in step (1) is used as catalyst B and then returned to the dry reforming reaction after heating.

2. The method according to claim 1, wherein, The molar ratio of methane to carbon dioxide in the raw material containing methane and carbon dioxide is 0.6-1.2:1, preferably 0.8-1.1:1; Preferably, the reaction conditions for the dry reforming reaction include: a reaction temperature of 600-900℃, more preferably 700-850℃; a reaction pressure of 0-2MPa, more preferably 0.1-0.5MPa; and a total mass hourly space velocity (WHSV) of 0.1-10h⁻¹ for methane and carbon dioxide. -1 Preferably 0.5-5h -1 .

3. The method according to claim 1 or 2, wherein, The catalyst comprises an active metal and a support; Preferably, the active metal is selected from at least one of Fe, Co, Ni, Pd and Pt, and is preferably Ni; Preferably, the support is selected from at least one of Al2O3, SiO2, MgO, TiO2, ZrO2 and ZnO, and more preferably Al2O3 and / or MgO; Preferably, the content of active metal elements in the catalyst is 1-20 wt%, more preferably 4-15 wt%, based on the total mass of the catalyst.

4. The method according to any one of claims 1-3, wherein, Step (1) also includes mixing the product stream containing syngas with a quenching medium to obtain quenched syngas; Preferably, the method further includes cooling the quenched syngas to obtain cooled syngas.

5. The method according to claim 4, wherein, The temperature of the quenched synthesis gas is not higher than 560°C, and preferably 280-510°C. Preferably, the quenching medium is water and / or cooled synthesis gas, and more preferably cooled synthesis gas.

6. The method according to any one of claims 1-5, wherein, In step (2), the circulation rate of catalyst A and the methane feed rate follow the formula F. A =a×G,F A Where A is the catalyst A circulation rate, a is a coefficient with a value ranging from 0.05 to 0.5, preferably from 0.1 to 0.3, and G is the methane feed flow rate.

7. The method according to any one of claims 1-6, wherein, The regeneration conditions include: a regeneration temperature of 600-900℃, preferably 700-850℃; and a regeneration pressure of 0-2MPa, preferably 0.1-0.5MPa. Preferably, the absolute value of the temperature difference between the regeneration temperature in step (2) and the dry reforming reaction temperature in step (1) is not greater than 100°C, and more preferably not greater than 70°C.

8. The method according to any one of claims 1-7, wherein, In step (2), the method further includes reducing the regenerated catalyst to obtain a reduced catalyst; Preferably, the reduction conditions include: in the presence of a reducing medium, the mass hourly space velocity of the reducing medium is 0.001-1 h⁻¹. -1 Preferably, it is 0.01-0.5h. -1 The reduction temperature is 600-900℃, preferably 700-850℃; the reduction pressure is 0-2MPa, preferably 0.1-0.5MPa. Preferably, the reducing medium is hydrogen.

9. The method according to any one of claims 1-8, wherein, The circulation rate of catalyst B is related to the methane feed rate according to formula F. B ×(t 加热 -t 反应 )=b×G,F B The amount of catalyst B circulating is t. 加热 The temperature (t) after catalyst B is heated is the numerical value. 反应 denoted as the dry reforming reaction temperature, b as a coefficient ranging from 300 to 1200, preferably 400 to 800, and G as the methane feed flow rate.

10. The method according to any one of claims 1-9, wherein, In step (3), the temperature difference between the temperature of catalyst B after heating and the temperature of the dry reforming reaction shall not be less than 30°C, preferably 50-100°C.

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