Carbon dioxide methanation reaction apparatus and method

Abstract

The application relates to the technical field of carbon dioxide conversion, and discloses a carbon dioxide methanation reaction device and method.The device comprises a reactor shell (1), the middle part of the reactor shell (1) is provided with a carbon dioxide feeding port (2), the two ends are respectively provided with a first product outlet (3) and a second product outlet (4), in the reactor shell (1), a first reaction zone (5) is formed between the carbon dioxide feeding port (2) and the first product outlet (3), and a second reaction zone (6) is formed between the carbon dioxide feeding port (2) and the second product outlet (4). Through the carbon dioxide methanation reaction device and method, the catalytic efficiency and hydrogen utilization rate can be effectively improved, the reaction catalyst deactivation rate and the catalytic reaction temperature can be reduced, and the energy-saving and emission-reducing target can be achieved.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide conversion, and more specifically to a carbon dioxide methanation reaction apparatus and method. Background Technology

[0002] Power-to-gas (P2G) technology refers to the use of electricity to electrolyze water into H2, which then reacts with CO2 to produce CH4. As a novel energy conversion and storage method, it provides a new pathway for renewable energy. It consists of two stages. The first stage utilizes excess electricity generated during off-peak hours to produce hydrogen through water electrolysis. This stage is simple and easy to implement, with an energy conversion efficiency of 75%–85%. Existing alkaline water electrolysis hydrogen production technology is very mature and has been widely applied. The second stage is methanation, which involves reacting the H2 and CO2 generated from water electrolysis with a catalyst to produce methane and water. This process has an energy conversion efficiency of approximately 75%–80%. Power-to-gas technology, as a novel energy conversion and storage method, provides a new pathway for renewable energy.

[0003] Currently, carbon dioxide methanation technology is considered one of the most efficient technologies for carbon dioxide recycling. Therefore, the carbon dioxide reforming reaction to produce methane has attracted increasing attention. On the one hand, this reaction effectively and rationally reduces carbon dioxide emissions; on the other hand, the reaction product, methane, serves as a combustible substance, providing energy. Conventional reactions of carbon dioxide and hydrogen to produce methane generally require the use of nickel-based catalysts and are carried out under high temperature and high pressure conditions. However, this easily leads to catalyst deactivation, significantly reducing reaction efficiency.

[0004] Therefore, there is an urgent need to develop a carbon dioxide methanation reactor and method that utilizes electro-gas technology to methanate carbon dioxide, thereby achieving the conversion of inorganic carbon into organic carbon, while simultaneously solving the problems of low catalyst conversion efficiency, high reaction temperature, and high deactivation rate. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of low catalyst conversion efficiency, high reaction temperature, high deactivation rate, and low carbon dioxide adsorption capacity in existing carbon dioxide methanation reactors and methods, and to provide a carbon dioxide methanation reactor and method. This invention provides a carbon dioxide methanation reactor that simultaneously applies hydrogen generated from water electrolysis to carbon dioxide methanation and catalyst reduction, reducing catalyst deactivation rate, saving catalyst processing time, and reducing hydrogen storage and transportation costs, thereby improving CO2 conversion rate. Simultaneously, it provides a carbon dioxide methanation method based on the above-mentioned reactor, which introduces nitrogen plasma treatment to enhance catalyst reactivity, lower the reaction temperature, significantly improve the dispersion of its active components, and increase CO2 adsorption capacity.

[0006] To achieve the above objectives, the present invention provides a carbon dioxide methanation reactor, which includes a reactor shell with a carbon dioxide inlet in the middle and a first product outlet and a second product outlet at each end. Inside the reactor shell, a first reaction zone is formed from the carbon dioxide inlet to the first product outlet, and a second reaction zone is formed from the carbon dioxide inlet to the second product outlet.

[0007] In the first reaction zone, a first movable baffle and a first catalytic reaction bed are sequentially arranged from the carbon dioxide inlet to the first product outlet, and a first hydrogen inlet is correspondingly provided in the first reaction zone. In the second reaction zone, a second movable baffle and a second catalytic reaction bed are sequentially arranged from the carbon dioxide inlet to the second product outlet, and a second hydrogen inlet is correspondingly provided in the second reaction zone.

[0008] Both the first and second movable partitions are equipped with one-way valves. When the first movable partition is closed and the second movable partition is open, the first movable partition can prevent gas in the second reaction zone from entering the first reaction zone, and excess hydrogen in the first reaction zone can enter the second reaction zone through the one-way valve on the first movable partition. When the second movable partition is closed and the first movable partition is open, the second movable partition can prevent gas in the first reaction zone from entering the second reaction zone, and excess hydrogen in the second reaction zone can enter the first reaction zone through the one-way valve on the second movable partition.

[0009] Preferably, the reactor shell is symmetrically arranged along the centerline of the carbon dioxide inlet.

[0010] Preferably, the first product outlet and the second product outlet are each equipped with a detection device for detecting the concentration of hydrogen and carbon dioxide.

[0011] Preferably, the first movable partition and the second movable partition are opened alternately in a cyclical manner.

[0012] A second aspect of the present invention provides a method for the methanation of carbon dioxide, which is carried out in the above-described apparatus and includes the following steps:

[0013] (1) Open the first movable partition and close the second movable partition. Introduce carbon dioxide from the carbon dioxide inlet and hydrogen generated by water electrolysis from the first hydrogen inlet. In the first catalytic reaction bed, carry out carbon dioxide methanation reaction. Introduce hydrogen generated by water electrolysis from the second hydrogen inlet. In the second catalytic reaction bed, carry out catalyst reduction reaction. The product is discharged through the first product outlet.

[0014] (2) Open the second movable partition and close the first movable partition. Introduce carbon dioxide from the carbon dioxide inlet and hydrogen generated by water electrolysis from the second hydrogen inlet. In the second catalytic reaction bed, carry out the carbon dioxide methanation reaction. Introduce hydrogen generated by water electrolysis from the first hydrogen inlet. In the first catalytic reaction bed, carry out the catalyst reduction reaction. The product is discharged through the second product outlet.

[0015] (3) Alternate between steps (1) and (2).

[0016] Preferably, the catalyst comprises a support and nickel particles dispersed on the support, and the catalyst is subjected to plasma treatment.

[0017] Preferably, the support is at least one of Al2O3 and CeO2.

[0018] Preferably, the content of nickel particles relative to 100 parts by weight of the carrier can be 5-15 parts by weight, more preferably 9-11 parts by weight.

[0019] Preferably, excess hydrogen gas in the catalytic reaction bed of the catalyst reduction reaction undergoes the carbon dioxide methanation reaction through the one-way valve.

[0020] Preferably, the method further includes detecting the concentrations of hydrogen and carbon dioxide separately using the detection device for detecting the concentrations of hydrogen and carbon dioxide.

[0021] According to the carbon dioxide methanation reactor of the present invention, hydrogen generated from water electrolysis during the power-to-gas conversion process is simultaneously applied to the carbon dioxide methanation reaction and the catalyst reduction reaction, saving catalyst processing time and reducing hydrogen storage and transportation costs. Furthermore, the carbon dioxide methanation reaction and catalyst reduction reaction are carried out in separate zones, ensuring sufficient catalyst reduction, thereby reducing catalyst deactivation and increasing carbon dioxide conversion rate. Excess hydrogen used for catalyst reduction is allowed to continue participating in the carbon dioxide methanation reaction via a one-way valve, avoiding hydrogen waste or accumulation, while simultaneously achieving full utilization of hydrogen and ensuring reactor safety. The synthesis method using this reactor utilizes plasma technology to highly disperse nickel particles on the support, significantly improving the dispersion of active components, thereby increasing catalyst activity and reducing reaction temperature. Therefore, the carbon dioxide methanation reactor and method of the present invention effectively improve catalyst conversion efficiency, achieve mutual conversion between electricity and natural gas, and utilize off-peak electricity to reduce power plant load regulation tasks and ensure the stability of boiler power generation. Attached Figure Description

[0022] Figure 1This is a schematic diagram of the carbon dioxide methanation reactor according to the present invention.

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Reactor shell; 2. Carbon dioxide inlet; 3. First product outlet; 4. Second product outlet; 5. First reaction zone; 51. First movable baffle; 52. First catalytic reaction bed; 53. First hydrogen inlet; 6. Second reaction zone; 61. Second movable baffle; 62. Second catalytic reaction bed; 63. Second hydrogen inlet. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] The carbon dioxide methanation reactor described in this invention is shown below. Figure 1 The device includes: a reactor shell 1, a carbon dioxide inlet 2 in the middle of the reactor shell 1, and a first product outlet 3 and a second product outlet 4 at each end. Inside the reactor shell 1, a first reaction zone 5 is formed from the carbon dioxide inlet 2 to the first product outlet 3, and a second reaction zone 6 is formed from the carbon dioxide inlet 2 to the second product outlet 4.

[0028] In the first reaction zone 5, a first movable baffle 51 and a first catalytic reaction bed 52 are arranged sequentially from the carbon dioxide inlet 2 to the first product outlet 3, and a first hydrogen inlet 53 is correspondingly provided in the first reaction zone 5.

[0029] In the second reaction zone 6, a second movable baffle 61 and a second catalytic reaction bed 62 are arranged sequentially from the carbon dioxide inlet 2 to the second product outlet 4, and a second hydrogen inlet 63 is correspondingly provided in the second reaction zone 6.

[0030] Both the first movable partition 51 and the second movable partition 61 are equipped with one-way valves. When the first movable partition 51 is closed and the second movable partition 61 is open, the first movable partition 51 can prevent gas in the second reaction zone 6 from entering the first reaction zone 5, and excess hydrogen in the first reaction zone 5 can enter the second reaction zone 6 through the one-way valve on the first movable partition 51. When the second movable partition 61 is closed and the first movable partition 51 is open, the second movable partition 61 can prevent gas in the first reaction zone 5 from entering the second reaction zone 6, and excess hydrogen in the second reaction zone 6 can enter the first reaction zone 5 through the one-way valve on the second movable partition 61. According to the device of the present invention, in the process of carbon dioxide methanation reaction, the carbon dioxide methanation reaction and the catalyst reduction reaction are carried out in separate sections, and a portion of the hydrogen generated by water electrolysis is drawn out for the catalyst reduction reaction, which improves the carbon dioxide conversion rate and methane selectivity, reduces the catalyst deactivation rate, realizes full utilization of hydrogen and device safety, and is suitable for carbon dioxide emission reduction and surplus power utilization in power plants.

[0031] In the apparatus described in this invention, the reactor shell 1 can be symmetrically arranged along the centerline of the carbon dioxide inlet 2.

[0032] In the apparatus described in this invention, in order to ensure that the gas concentration does not exceed the safe range, the first product outlet 3 and the second product outlet 4 are preferably each equipped with a detection device for detecting the concentration of hydrogen and carbon dioxide.

[0033] In the apparatus described in this invention, the detection device for detecting the concentrations of hydrogen and carbon dioxide can be a hydrogen and carbon dioxide concentration detector.

[0034] In the device described in this invention, in order to reduce the deactivation rate of the catalyst, the first movable partition 51 and the second movable partition 61 are alternately and cyclically opened.

[0035] In some embodiments, the carbon dioxide methanation reactor includes a reactor shell 1, which is symmetrically arranged along the centerline of a carbon dioxide inlet 2. A first product outlet 3 and a second product outlet 4 are respectively provided at both ends of the reactor shell 1. Within the reactor shell 1, a first reaction zone 5 is formed from the carbon dioxide inlet 2 to the first product outlet 3, and a second reaction zone 6 is formed from the carbon dioxide inlet 2 to the second product outlet 4. In the first reaction zone 5, a first movable baffle 51 and a first catalytic reaction bed 52 are sequentially arranged in the direction from the carbon dioxide inlet 2 to the first product outlet 3, and a first hydrogen inlet 53 is correspondingly provided in the first reaction zone 5. In the second reaction zone 6, a second movable baffle 61 and a second catalytic reaction bed 62 are sequentially arranged in the direction from the carbon dioxide inlet 2 to the second product outlet 4, and a second hydrogen inlet 63 is correspondingly provided in the second reaction zone 6. Both the first movable partition 51 and the second movable partition 61 are equipped with one-way valves. When the first movable partition 51 is closed and the second movable partition 61 is open, the first movable partition 51 prevents gas in the second reaction zone 6 from entering the first reaction zone 5, and excess hydrogen in the first reaction zone 5 can enter the second reaction zone 6 through the one-way valve on the first movable partition 51. When the second movable partition 61 is closed and the first movable partition 51 is open, the second movable partition 61 prevents gas in the first reaction zone 5 from entering the second reaction zone 6, and excess hydrogen in the second reaction zone 6 can enter the first reaction zone 5 through the one-way valve on the second movable partition 61. The first product outlet 3 and the second product outlet 4 are each equipped with a detection device for detecting the concentration of hydrogen and carbon dioxide. The first movable partition 51 and the second movable partition 61 are opened and closed alternately in a cyclical manner.

[0036] The present invention also provides a method for carbon dioxide methanation reaction, which is carried out in the above-described apparatus and includes the following steps:

[0037] (1) Open the first movable partition 51 and close the second movable partition 61. Introduce carbon dioxide from the carbon dioxide inlet 2 and hydrogen generated by water electrolysis from the first hydrogen inlet 53. Introduce carbon dioxide methanation reaction in the first catalytic reaction bed 52. Introduce hydrogen generated by water electrolysis from the second hydrogen inlet 63. Introduce catalyst reduction reaction in the second catalytic reaction bed 62. The product is discharged through the first product outlet 3.

[0038] (2) Open the second movable partition 61 and close the first movable partition 51. Introduce carbon dioxide from the carbon dioxide inlet 2 and hydrogen generated by water electrolysis from the second hydrogen inlet 63. Carry out the carbon dioxide methanation reaction in the second catalytic reaction bed 62. Introduce hydrogen generated by water electrolysis from the first hydrogen inlet 53. Carry out the catalyst reduction reaction in the first catalytic reaction bed 52. The product is discharged through the second product outlet 4.

[0039] (3) Alternate between steps (1) and (2).

[0040] According to the method described in this invention, hydrogen generated by water electrolysis is simultaneously applied to the carbon dioxide methanation reaction and the catalyst reduction reaction, which reduces the catalyst deactivation rate, improves the utilization rate of hydrogen, reduces the storage and transportation costs of hydrogen, improves the conversion rate of carbon dioxide, and can also utilize surplus off-peak electricity to achieve the goal of energy conservation and emission reduction, which is of great significance for achieving sustainable green development of the global economy.

[0041] In the method described in this invention, the catalyst may include a support and nickel particles dispersed on the support, and in order to improve the dispersion of the active component and the selectivity of methane, reduce the reaction temperature and improve the resistance to coking, the catalyst is preferably subjected to plasma treatment.

[0042] In the method described in this invention, the support is Al2O3 and / or CeO2, preferably CeO2.

[0043] In the method described in this invention, the content of nickel particles relative to 100 parts by weight of the carrier can be 5-15 parts by weight, preferably 9-11 parts by weight.

[0044] In this invention, the catalyst can be commercially available or prepared using conventional methods in the art. For specific preparation methods, please refer to the content disclosed in patent application CN111359626A.

[0045] In the method described in this invention, excess hydrogen gas in the catalytic reaction bed of the catalyst reduction reaction undergoes the carbon dioxide methanation reaction through the one-way valve.

[0046] In the method described in this invention, the method further includes detecting the concentrations of hydrogen and carbon dioxide respectively using the detection device for detecting the concentrations of hydrogen and carbon dioxide.

[0047] In the method described in this invention, during the carbon dioxide methanation reaction, the carbon dioxide space velocity can be 6000-10000 h⁻¹. -1 Preferably 8000-9000h -1 The space velocity of hydrogen can be 24,000-40,000 h⁻¹.-1 Preferably 32000-36000h -1 .

[0048] In the method described in this invention, the conditions for the carbon dioxide methanation reaction may include: a temperature of 200-350°C, preferably 250-300°C; and a pressure of 0.01-3 MPa, preferably 0.1-2.5 MPa. In this document, pressure refers to gauge pressure.

[0049] In the method described in this invention, during the catalyst reduction reaction, the hydrogen space velocity can be 8000-16000 h⁻¹. -1 Preferably 10000-15000h -1 .

[0050] In the method described in this invention, the conditions for the catalyst reduction reaction may include: a temperature of 600-900℃, preferably 700-900℃; and a pressure of 0.01-3MPa, preferably 0.1-2.5MPa.

[0051] In some embodiments, the carbon dioxide methanation reaction is carried out in the above-described apparatus, and the method includes:

[0052] The plasma-treated catalyst is added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 is opened and the second movable partition 61 is closed. Carbon dioxide is fed from the carbon dioxide inlet 2 at a space velocity of 6000-10000 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 24,000-40,000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 200-350℃ and the pressure to 0.01-3MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 8000-16000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62. The temperature is adjusted to 600-900℃ and the pressure to 0.01-3MPa for catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 6000-10000 h⁻¹. -1 Carbon dioxide is introduced through the second hydrogen inlet 63 at a space velocity of 24,000-40,000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 200-350℃ and the pressure to 0.01-3MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 8000-16000 h⁻¹. -1Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 600-900℃ and the pressure to 0.01-3MPa for catalytic reduction. The product is discharged through the second product outlet 4. This process is repeated alternately. During the reaction, excess hydrogen gas in the catalytic reaction bed undergoes carbon dioxide methanation through the one-way valve. The detection devices for hydrogen and carbon dioxide concentrations detect their concentrations respectively.

[0053] In other embodiments, the carbon dioxide methanation reaction is carried out in the above-described apparatus, and the method includes:

[0054] The plasma-treated catalyst is added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 is opened and the second movable partition 61 is closed. Carbon dioxide is fed from the carbon dioxide inlet 2 at a space velocity of 8000-9000 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 32,000-36,000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 250-300℃ and the pressure to 0.1-2.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 10000-15000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62. The temperature is adjusted to 700-900℃ and the pressure to 0.1-2.5MPa to carry out a catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 8000-9000 h⁻¹. -1 Carbon dioxide is introduced through the second hydrogen inlet 63 at a space velocity of 32,000-36,000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 250-300℃ and the pressure to 0.1-2.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 10000-15000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 700-900℃ and the pressure to 0.1-2.5MPa for catalytic reduction. The product is discharged through the second product outlet 4. This process is repeated alternately. During the reaction, excess hydrogen gas in the catalytic reaction bed undergoes carbon dioxide methanation through the one-way valve. The detection devices for hydrogen and carbon dioxide concentrations detect their concentrations respectively.

[0055] The apparatus and method for the continuous synthesis of tetrafluoroethane-β-sulfonolactone according to the present invention are further illustrated below through examples. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0056] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0057] In the following examples, the carbon dioxide methanation reaction process is as follows: Figure 1 The illustrated apparatus specifically includes a reactor shell 1, which is symmetrically arranged along the centerline of a carbon dioxide inlet 2. A first product outlet 3 and a second product outlet 4 are respectively provided at both ends of the reactor shell 1. Within the reactor shell 1, a first reaction zone 5 is formed from the carbon dioxide inlet 2 to the first product outlet 3, and a second reaction zone 6 is formed from the carbon dioxide inlet 2 to the second product outlet 4. In the first reaction zone 5, a first movable baffle 51 and a first catalytic reaction bed 52 are sequentially arranged in the direction from the carbon dioxide inlet 2 to the first product outlet 3, and a first hydrogen inlet 53 is correspondingly provided in the first reaction zone 5. In the second reaction zone 6, a second movable baffle 61 and a second catalytic reaction bed 62 are sequentially arranged in the direction from the carbon dioxide inlet 2 to the second product outlet 4, and a second hydrogen inlet 63 is correspondingly provided in the second reaction zone 6. Both the first movable partition 51 and the second movable partition 61 are equipped with one-way valves. When the first movable partition 51 is closed and the second movable partition 61 is open, the first movable partition 51 prevents gas in the second reaction zone 6 from entering the first reaction zone 5, and excess hydrogen in the first reaction zone 5 can enter the second reaction zone 6 through the one-way valve on the first movable partition 51. When the second movable partition 61 is closed and the first movable partition 51 is open, the second movable partition 61 prevents gas in the first reaction zone 5 from entering the second reaction zone 6, and excess hydrogen in the second reaction zone 6 can enter the first reaction zone 5 through the one-way valve on the second movable partition 61. The first product outlet 3 and the second product outlet 4 are each equipped with a detection device for detecting the concentration of hydrogen and carbon dioxide. The first movable partition 51 and the second movable partition 61 are opened and closed alternately in a cyclical manner.

[0058] Example 1

[0059] 50g of plasma-treated nickel-based catalyst (synthesized according to the method in patent application CN111359626A) was added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 was opened and the second movable partition 61 was closed. Carbon dioxide was fed from the carbon dioxide inlet 2 at a space velocity of 8000 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 32000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 270℃ and the pressure to 0.1MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 10000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 700℃ and the pressure to 0.1MPa for catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 8000 h⁻¹. -1 Carbon dioxide is introduced from the second hydrogen inlet 63 at a space velocity of 32000 h⁻¹. -1 Hydrogen gas produced by water electrolysis is introduced into the second catalytic reaction bed 62, and the temperature is adjusted to 270℃ and the pressure to 0.1MPa to carry out the carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 10000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 700°C and the pressure to 0.1 MPa to carry out the catalytic reduction reaction. The product is discharged through the second product outlet 4. The above operations are carried out alternately.

[0060] The product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably; the CO2 conversion rate was calculated by the N2-internal standard method, and the methane selectivity was calculated by the C-based internal normalization method; the calculation data are shown in Table 1.

[0061] Example 2

[0062] 50g of plasma-treated nickel-based catalyst (synthesized according to the method in patent application CN111359626A) was added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 was opened and the second movable partition 61 was closed. Carbon dioxide was fed from the carbon dioxide inlet 2 at a space velocity of 8500 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 34000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 250℃ and the pressure to 1.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 12000 h⁻¹. -1Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 800℃ and the pressure to 1.5MPa for catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 8500 h⁻¹. -1 Carbon dioxide is introduced from the second hydrogen inlet 63 at a space velocity of 34,000 h⁻¹. -1 Hydrogen gas produced by water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 250℃ and the pressure to 1.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 12000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 800℃ and the pressure to 1.5MPa to carry out the catalytic reduction reaction. The product is discharged through the second product outlet 4. The above operations are carried out alternately.

[0063] The product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably; the CO2 conversion rate was calculated by the N2-internal standard method, and the methane selectivity was calculated by the C-based internal normalization method; the calculation data are shown in Table 1.

[0064] Example 3

[0065] 50g of plasma-treated nickel-based catalyst (synthesized according to the method in patent application CN111359626A) was added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 was opened and the second movable partition 61 was closed. Carbon dioxide was fed from the carbon dioxide inlet 2 at a space velocity of 9000 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 36,000 h⁻¹. -1 Hydrogen gas produced by water electrolysis is introduced into the first catalytic reaction bed 52, where the temperature is adjusted to 300℃ and the pressure to 2.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 15000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 900℃ and the pressure to 2.5MPa for catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 9000 h⁻¹. -1 Carbon dioxide is introduced from the second hydrogen inlet 63 at a space velocity of 36,000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 300℃ and the pressure to 2.5MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 15000 h⁻¹. -1Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 900℃ and the pressure to 2.5MPa to carry out the catalytic reduction reaction. The product is discharged through the second product outlet 4. The above operations are carried out alternately.

[0066] The product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably; the CO2 conversion rate was calculated by the N2-internal standard method, and the methane selectivity was calculated by the C-based internal normalization method; the calculation data are shown in Table 1.

[0067] Comparative Example 1

[0068] 50g of nickel-based catalyst (synthesized according to the method in patent application CN111359626A) is added to the first catalytic reaction bed 52 and the second catalytic reaction bed 62. The first movable partition 51 is opened and the second movable partition 61 is closed. Carbon dioxide is fed from the carbon dioxide inlet 2 at a space velocity of 8500 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 34000 h⁻¹. -1 Hydrogen gas produced by water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 400℃ and the pressure to 0.2MPa to carry out the carbon dioxide methanation reaction; hydrogen gas is then introduced from the second hydrogen inlet 63 at a space velocity of 12000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 800℃ and the pressure to 0.2MPa for catalytic reduction reaction. The product is discharged through the first product outlet 3. After a period of time, the second movable partition 61 is opened and the first movable partition 51 is closed, allowing carbon dioxide to flow from the carbon dioxide inlet 2 at a space velocity of 8500 h⁻¹. -1 Carbon dioxide is introduced from the second hydrogen inlet 63 at a space velocity of 34,000 h⁻¹. -1 Hydrogen gas produced by water electrolysis is introduced into the second catalytic reaction bed 62, where the temperature is adjusted to 400℃ and the pressure to 0.2MPa, to carry out a carbon dioxide methanation reaction; hydrogen gas is introduced from the first hydrogen inlet 53 at a space velocity of 12000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 800℃ and the pressure to 0.2MPa to carry out the catalytic reduction reaction. The product is discharged through the second product outlet 4. The above operations are carried out alternately.

[0069] The product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably; the CO2 conversion rate was calculated by the N2-internal standard method, and the methane selectivity was calculated by the C-based internal normalization method; the calculation data are shown in Table 1.

[0070] Comparative Example 2

[0071] Add 50g of plasma-treated nickel-based catalyst (synthesized according to the method in patent application CN111359626A) to the first catalytic reaction bed 52. Open the first movable partition 51, close the second movable partition 61, and feed carbon dioxide from the carbon dioxide inlet 2 at a space velocity of 8500 h⁻¹. -1 Carbon dioxide is introduced from the first hydrogen inlet 53 at a space velocity of 34000 h⁻¹. -1 Hydrogen gas generated from water electrolysis is introduced into the first catalytic reaction bed 52, and the temperature is adjusted to 280℃ and the pressure to 0.2MPa to carry out the carbon dioxide methanation reaction.

[0072] The product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably; the CO2 conversion rate was calculated by the N2-internal standard method, and the methane selectivity was calculated by the C-based internal normalization method; the calculation data are shown in Table 1.

[0073] Table 1

[0074]

[0075] As can be seen from the results in Table 1, the embodiments using the carbon dioxide methanation reaction apparatus and method of the present invention all have high carbon dioxide conversion rate and methane selectivity, indicating that the apparatus and method of the present invention can effectively improve catalytic efficiency and reduce catalyst deactivation rate and reaction temperature.

[0076] 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 carbon dioxide methanation reactor, characterized in that, The device includes a reactor shell (1), a carbon dioxide inlet (2) is provided in the middle of the reactor shell (1), and a first product outlet (3) and a second product outlet (4) are provided at both ends. Inside the reactor shell (1), a first reaction zone (5) is formed from the carbon dioxide inlet (2) to the first product outlet (3), and a second reaction zone (6) is formed from the carbon dioxide inlet (2) to the second product outlet (4). In the first reaction zone (5), a first movable partition (51) and a first catalytic reaction bed (52) are arranged sequentially from the carbon dioxide inlet (2) to the first product outlet (3), and a first hydrogen inlet (53) is correspondingly provided in the first reaction zone (5). In the second reaction zone (6), a second movable baffle (61) and a second catalytic reaction bed (62) are arranged sequentially from the carbon dioxide inlet (2) to the second product outlet (4), and a second hydrogen inlet (63) is correspondingly provided in the second reaction zone (6). Both the first movable partition (51) and the second movable partition (61) are equipped with one-way valves. When the first movable partition (51) is closed and the second movable partition (61) is open, the first movable partition (51) can prevent the gas in the second reaction zone (6) from entering the first reaction zone (5), and the excess hydrogen in the first reaction zone (5) can enter the second reaction zone (6) through the one-way valve on the first movable partition (51). When the second movable partition (61) is closed and the first movable partition (51) is open, the second movable partition (61) can prevent the gas in the first reaction zone (5) from entering the second reaction zone (6), and the excess hydrogen in the second reaction zone (6) can enter the first reaction zone (5) through the one-way valve on the second movable partition (61).

2. The apparatus according to claim 1, characterized in that, The reactor shell (1) is symmetrically arranged along the centerline of the carbon dioxide inlet (2).

3. The apparatus according to claim 1 or 2, characterized in that, The first product outlet (3) and the second product outlet (4) are each equipped with a detection device for detecting the concentration of hydrogen and carbon dioxide.

4. The apparatus according to claim 1 or 2, characterized in that, The first movable partition (51) and the second movable partition (61) are opened alternately in a cycle.

5. A method for the methanation of carbon dioxide, characterized in that, The method is performed in the apparatus according to any one of claims 1-4, and the method includes the following steps: (1) Open the first movable partition (51), close the second movable partition (61), introduce carbon dioxide from the carbon dioxide inlet (2), introduce hydrogen generated by water electrolysis from the first hydrogen inlet (53), and carry out carbon dioxide methanation reaction in the first catalytic reaction bed (52); introduce hydrogen generated by water electrolysis from the second hydrogen inlet (63), and carry out catalyst reduction reaction in the second catalytic reaction bed (62), and discharge the product through the first product outlet (3); (2) Open the second movable partition (61), close the first movable partition (51), introduce carbon dioxide from the carbon dioxide inlet (2), introduce hydrogen generated by water electrolysis from the second hydrogen inlet (63), and carry out carbon dioxide methanation reaction in the second catalytic reaction bed (62); introduce hydrogen generated by water electrolysis from the first hydrogen inlet (53), carry out catalyst reduction reaction in the first catalytic reaction bed (52), and discharge the product through the second product outlet (4); (3) Alternate between steps (1) and (2).

6. The method according to claim 5, characterized in that, The catalyst comprises a support and nickel particles dispersed on the support, and the catalyst is subjected to plasma treatment.

7. The method according to claim 6, characterized in that, The support is at least one of Al2O3 and CeO2.

8. The method according to claim 6 or 7, characterized in that, The content of nickel particles is 5-15 parts by weight relative to 100 parts by weight of the carrier.

9. The method according to claim 8, characterized in that, The content of nickel particles is 9-11 parts by weight relative to 100 parts by weight of the carrier.

10. The method according to any one of claims 5-7, characterized in that, Excess hydrogen gas in the catalytic reaction bed of the catalyst reduction reaction undergoes the carbon dioxide methanation reaction through the one-way valve.

11. The method according to claim 5, characterized in that, The method further includes: each of the first product outlet (3) and the second product outlet (4) is provided with a detection device for detecting the concentration of hydrogen and carbon dioxide, and the concentration of hydrogen and carbon dioxide is detected by the detection device for detecting the concentration of hydrogen and carbon dioxide respectively.

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