System and method for coupling carbon dioxide capture and in-situ methanation

Abstract

The invention provides a system and method for coupling carbon dioxide capture and in-situ methanation, the system comprises a gas conveying and switching unit, an adsorption and conversion unit, a product collection unit and a pressure control unit, the gas conveying and switching unit comprises a nitrogen pipeline, a flue gas pipeline and a hydrogen pipeline; the adsorption and conversion unit is filled with a composite material with double functions of adsorption and catalysis; the product collection unit is connected to the downstream of the adsorption and conversion unit; and the pressure control unit is connected between the adsorption and conversion unit and the product collection unit and comprises a back pressure valve and an electromagnetic valve which are connected to the main pipeline. According to the method, carbon emission reduction of the petrochemical industry is achieved, high-added-value utilization of carbon dioxide is achieved, and liquid fuel is provided for the petrochemical industry; on the other hand, adsorption and conversion are completed in the same reactor, so that high cost and high energy consumption in the process of compressing, liquefying and transporting carbon dioxide connected with carbon capture and utilization are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture and methanol preparation, and in particular to a system and method for coupling carbon dioxide capture and in-situ methanolization. Background Art

[0002] Global warming has become a global concern, and large-scale carbon dioxide emissions are its main cause. my country has actively responded to international calls and put forward a "dual carbon" commitment, that is, to achieve a peak in carbon dioxide emissions before 2030 and achieve carbon neutrality before 2060. The flue gas temperature discharged during the petrochemical industry production process is usually between 200℃ and 400℃, and the carbon dioxide concentration is between 10-20%. In order to balance the contradiction between the development of the petrochemical industry and the "dual carbon" goals, carbon dioxide capture, utilization and storage technology is becoming a new way to mitigate carbon dioxide emissions.

[0003] However, carbon dioxide capture, utilization and storage technology currently faces a series of challenges, including high energy consumption, immature technology, low conversion rate of carbon utilization process, and high cost of carbon dioxide compression, liquefaction and transportation process connecting carbon capture and utilization, which seriously restrict the development and application of technology.

[0004] Among the carbon products of carbon dioxide conversion, methanol is called "liquid sunshine" because of its economic benefits and practical value. Methanol is widely used in the chemical industry and fuel industry. It can also be used as an energy-intensive synthetic fuel directly in the shipping industry and industries that are difficult to decarbonize (such as heavy-duty vehicles and aviation). However, the process of synthesizing methanol from carbon dioxide and hydrogen under the action of a catalyst is still facing the technical bottleneck of low conversion rate, and there is still a certain distance from achieving industrialization. At present, research on systems and methods for capturing carbon dioxide from petrochemical flue gas and converting it into methanol in situ is still blank. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiment of the present invention provides a system and method for coupling carbon dioxide capture and in-situ methanolization, which not only achieves carbon emission reduction in the petrochemical industry, but also achieves high value-added utilization of carbon dioxide, and the adsorption and conversion are completed in the same reactor, reducing costs and energy consumption.

[0006] In one aspect, an embodiment of the present invention proposes a system for coupling carbon dioxide capture and in-situ methanolization, comprising: a gas delivery and switching unit, an adsorption and conversion unit, a product collection unit and a pressure control unit, wherein the gas delivery and switching unit comprises a nitrogen pipeline, a flue gas pipeline and a hydrogen pipeline, and the nitrogen pipeline, the flue gas pipeline and the hydrogen pipeline are connected in parallel to the main pipeline; the adsorption and conversion unit is connected to the main pipeline, and the adsorption and conversion unit is filled with a composite material with dual functions of adsorption and catalysis to complete carbon dioxide adsorption and in-situ methanolization, and a temperature regulating mechanism is provided in the adsorption and conversion unit; the product collection unit is connected to the downstream of the adsorption and conversion unit to collect the generated methanol; the pressure control unit is connected between the adsorption and conversion unit and the product collection unit, and the pressure control unit comprises a back pressure valve and a solenoid valve connected to the main pipeline.

[0007] In some embodiments, the product collection unit includes a serpentine condenser and a collection tank, and the serpentine condenser is arranged at the feed inlet of the collection tank.

[0008] In some embodiments, the nitrogen pipeline is connected to a first pressure reducing valve and a first flow valve, the flue gas pipeline is connected to a second pressure reducing valve and a second flow valve, and the hydrogen pipeline is connected to a third pressure reducing valve and a third flow valve.

[0009] Another aspect of the present invention provides a method for coupling carbon dioxide capture and in-situ methanolization, using the above system, including the following steps:

[0010] S1, nitrogen is introduced into the adsorption and conversion unit, the temperature in the adsorption and conversion unit is raised to 300-350°C and maintained for a period of time to pretreat the composite material, and the pretreated gas is discharged through the channel of the solenoid valve;

[0011] S2, introducing flue gas into the adsorption and conversion unit, the composite material in the adsorption and conversion unit adsorbs carbon dioxide in the flue gas, and the adsorbed low-carbon flue gas is discharged through the channel of the solenoid valve;

[0012] S3, nitrogen is introduced into the adsorption and conversion unit for purging, and the purged gas is discharged through the channel of the solenoid valve;

[0013] S4, hydrogen is introduced into the adsorption and conversion unit for purging, and the purged gas is discharged through the channel of the solenoid valve;

[0014] S5, close the channel of the solenoid valve, adjust the back pressure valve and the pressure of the hydrogen, introduce hydrogen into the adsorption and conversion unit, raise the temperature in the adsorption and conversion unit to 300-350°C, and collect the methanol generated by the reaction of hydrogen and carbon dioxide into the product collection unit.

[0015] In some embodiments, the composite material is a mixture of NaNO3-modified MgO and zinc oxide-zirconium oxide bimetallic oxide, and the mass ratio of NaNO3-modified MgO to zinc oxide-zirconium oxide bimetallic oxide is 1:4.

[0016] In some embodiments, the particle size of the NaNO3-modified MgO is 0.2-0.3 μm, and the particle size of the zinc oxide-zirconium oxide bimetallic oxide is 0.1-0.2 μm.

[0017] In some embodiments, in the NaNO3-modified MgO, the molecular ratio of Na to Mg is 1:9.

[0018] In some embodiments, the preparation method of NaNO3-modified MgO comprises the following steps:

[0019] P1, dissolving magnesium acetate tetrahydrate and urea in deionized water to obtain a first mixed solution, adjusting the pH value of the first mixed solution to 9.0, and then transferring it to a Teflon reactor;

[0020] P2, placing a Teflon reactor in a muffle furnace for heating, and after the reaction of magnesium acetate tetrahydrate and urea is completed, naturally cooling to room temperature, opening the Teflon reactor, filtering and collecting a white precipitate, and washing and drying the white precipitate to obtain a white powder;

[0021] P3, calcining the white powder in air to obtain MgO;

[0022] P4, dissolving MgO and NaNO3 in ethanol, stirring to obtain a mixed solution, and drying the mixed solution to obtain a dry white powder;

[0023] P5, the dried white powder was calcined in air to obtain NaNO3-modified MgO.

[0024] In some embodiments, the method for preparing the zinc oxide zirconium oxide bimetallic oxide comprises the following steps:

[0025] Q1, dissolving zinc nitrate hexahydrate and zirconium nitrate pentahydrate in deionized water to obtain a second mixed solution,

[0026] Q2, under stirring, adding ammonium carbonate solution to the second mixed solution to form a suspension, heating and stirring, fully reacting, cooling to room temperature, collecting precipitates after filtration, washing and drying the precipitates to obtain white powder;

[0027] Q3, calcining the white powder, and then reducing it by heating in a pure hydrogen atmosphere to obtain zinc oxide and zirconium oxide bimetallic oxides.

[0028] In some embodiments, in step S5, the pressure of the back pressure valve is adjusted to 3 MPa, the pressure of the hydrogen introduced is adjusted by the third pressure reducing valve of the hydrogen pipeline, the flow rate of the hydrogen is adjusted to 100 ml / min by the third flow valve, and the gas required for pressure boosting is discharged through the channel of the back pressure valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0030] in:

[0031] Figure 1 It is a schematic structural diagram of a system for coupling carbon dioxide capture and in-situ methanolization in an embodiment of the present invention;

[0032] Description of reference numerals:

[0033] 1. Gas delivery and switching unit; 11. First pressure reducing valve; 12. First flow valve; 13. Second pressure reducing valve; 14. Second flow valve; 15. Third pressure reducing valve; 16. Third flow valve; 17. Mixing tank; 2. Adsorption and conversion unit; 21. Composite material; 3. Pressure control unit; 31. Back pressure valve; 32. Solenoid valve; 4. Product collection unit; 41. Serpentine condenser; 42. Collection tank. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] The following describes a system and method for coupling carbon dioxide capture and in-situ methanolization according to an embodiment of the present invention with reference to the accompanying drawings.

[0036] like Figure 1 As shown, an embodiment of the present invention proposes a system for coupling carbon dioxide capture and in-situ methanolization, including: a gas transportation and switching unit 1, an adsorption and conversion unit 2, a product collection unit 4 and a pressure control unit 3, the gas transportation and switching unit 1 includes a nitrogen pipeline, a flue gas pipeline and a hydrogen pipeline, the nitrogen pipeline, the flue gas pipeline and the hydrogen pipeline are connected to the main pipeline in parallel; the adsorption and conversion unit 2 is connected to the main pipeline, the adsorption and conversion unit 2 is filled with a composite material 21 with adsorption and catalytic dual functions to complete carbon dioxide adsorption and in-situ methanolization, and a temperature regulating mechanism is provided in the adsorption and conversion unit 2; the product collection unit 4 is connected to the downstream of the adsorption and conversion unit 2 to collect the generated methanol; the pressure control unit 3 is connected between the adsorption and conversion unit 2 and the product collection unit 4, and the pressure control unit 3 includes a back pressure valve 31 and a solenoid valve 32 connected to the main pipeline.

[0037] The embodiment of the present invention achieves both carbon emission reduction in the petrochemical industry and high value-added utilization of carbon dioxide by providing a gas transport and switching unit 1, an adsorption and conversion unit 2, a product collection unit 4 and a pressure control unit 3, thereby providing liquid fuel for the petrochemical industry. On the other hand, adsorption and conversion are completed in the same reactor, avoiding the complex system of two reactors and greatly reducing the high cost and high energy consumption of the carbon dioxide compression, liquefaction and transportation process connecting carbon capture and utilization.

[0038] By providing the pressure control unit 3 , it is possible to discharge the gas in the adsorption and conversion unit 2 under normal pressure conditions, and to increase and maintain the pressure in the adsorption and conversion unit 2 .

[0039] It should be noted that the adsorption and conversion unit 2 is specifically an adsorption conversion device, and any device that can achieve this function is not limited here.

[0040] Furthermore, a gas mixing tank 17 is connected to the main pipe.

[0041] In some embodiments, the product collection unit 4 includes a serpentine condenser 41 and a collection tank 42, wherein the serpentine condenser 41 is disposed at the feed inlet of the collection tank 42. By providing the serpentine condenser 41, the collected gaseous methanol can be converted into liquid methanol for collection.

[0042] In some embodiments, a first pressure reducing valve 11 and a first flow valve 12 are connected to the nitrogen pipeline, a second pressure reducing valve 13 and a second flow valve 14 are connected to the flue gas pipeline, and a third pressure reducing valve 15 and a third flow valve 16 are connected to the hydrogen pipeline.

[0043] Another aspect of the present invention provides a method for coupling carbon dioxide capture and in-situ methanolization, using the above system, including the following steps:

[0044] S1, nitrogen is introduced into the adsorption and conversion unit 2, and the temperature in the adsorption and conversion unit 2 is raised to 300-350°C and maintained for a period of time to pretreat the composite material 21, and the pretreated gas is discharged through the channel of the solenoid valve 32;

[0045] S2, flue gas is introduced into the adsorption and conversion unit 2, the composite material 21 in the adsorption and conversion unit 2 adsorbs carbon dioxide in the flue gas, and the adsorbed low-carbon flue gas is discharged through the channel of the solenoid valve 32;

[0046] S3, nitrogen is introduced into the adsorption and conversion unit 2 for purging, and the purged gas is discharged through the channel of the solenoid valve 32;

[0047] S4, hydrogen is introduced into the adsorption and conversion unit 2 for purging, and the purged gas is discharged through the channel of the solenoid valve 32;

[0048] S5, close the channel of the solenoid valve 32, adjust the back pressure valve 31 and the pressure of the hydrogen, introduce hydrogen into the adsorption and conversion unit 2, raise the temperature in the adsorption and conversion unit 2 to 300-350°C, and collect the methanol generated by the reaction of hydrogen and carbon dioxide into the product collection unit 4.

[0049] The method of the embodiment of the present invention is based on the characteristics of the medium-temperature flue gas generated by the cracking furnace and reactor of the petrochemical industry, and directly transports the flue gas to the adsorption and conversion unit 2 for adsorption; after a period of adsorption, the flue gas is switched to nitrogen and hydrogen for purging in sequence, and the system pressure is increased after purging. After the pressure is increased, the temperature of the adsorption and conversion unit 2 is increased to convert the adsorbed carbon dioxide into methanol, and this cycle is repeated.

[0050] The system and method for coupled carbon capture and in-situ methanolization of flue gas from cracking furnaces and reactors in the petrochemical industry provided by the present invention, on the one hand, the adsorption and conversion unit 2 is filled with an adsorption / catalysis dual-functional metal composite material, which has a high carbon dioxide adsorption capacity and high catalytic activity, thereby achieving both carbon emission reduction in the petrochemical industry and high value-added utilization of carbon dioxide; on the other hand, adsorption and conversion are completed in the same reactor, avoiding the complex system of two reactors, and greatly reducing the high cost and high energy consumption of the carbon dioxide compression, liquefaction and transportation process connecting carbon capture and utilization.

[0051] It should be noted that step S1 is a process of pretreating the composite material 21 , which is used to remove water and carbon dioxide naturally adsorbed in the adsorption active components in the composite material 21 during the synthesis and storage process, thereby improving the adsorption performance of the adsorption active components.

[0052] Further, the method of coupling carbon dioxide capture with in-situ methanolization comprises the following steps:

[0053] (1) Pretreatment of composite materials: The nitrogen gas is pressure-regulated by the first pressure reducing valve 11, and the flow rate is adjusted to 40 ml / min by the first flow valve 12, and then introduced into the adsorption and conversion unit 2. The temperature of the adsorption and conversion unit 2 is adjusted to 300-350°C and maintained for 1 hour. The pretreated gas is discharged through the channel of the solenoid valve 32 of the pressure control unit 3.

[0054] (2) Flue gas carbon dioxide adsorption: The carbon dioxide concentration in the flue gas is fixed at 15%. The flue gas is pressure-regulated by the second pressure reducing valve 13, and the flow rate is regulated to 40 ml / min by the second flow valve 14. The flue gas is introduced into the adsorption and conversion unit 2. The temperature of the adsorption and conversion unit 2 is regulated to 250-300° C. After adsorption by the composite material 21 for 1 hour, the carbon dioxide in the flue gas is captured, and the adsorbed low-carbon flue gas is discharged through the channel of the solenoid valve 32;

[0055] (3) Nitrogen purging: The nitrogen is regulated in pressure by the first pressure reducing valve 11, and the flow rate is regulated to 40 ml / min by the first flow valve 12, and then introduced into the adsorption and conversion unit 2, and the temperature is kept constant, i.e., 250-300° C. The purged gas is discharged through the channel of the solenoid valve 32;

[0056] (4) Hydrogen purge: The hydrogen is regulated in pressure by the third pressure reducing valve 15, and the flow rate is regulated to 100 ml / min by the third flow valve 16, and then introduced into the adsorption and conversion unit 2, and the temperature is kept constant, i.e., 250-300° C. The purged gas is discharged through the channel of the solenoid valve 32;

[0057] (5) System pressure increases: close the channel of the solenoid valve 32, adjust the pressure of the back pressure valve 31 to 3 MPa, adjust the pressure of hydrogen through the third pressure reducing valve 15, adjust the flow rate to 100 ml / min through the third flow valve 16, maintain the temperature of the adsorption and conversion unit 2 unchanged, i.e. 250-300 ° C, last for 50 min, and the gas required for pressure increase is discharged through the channel of the back pressure valve 31;

[0058] (6) In-situ conversion of carbon dioxide to methanol: The temperature of the adsorption and conversion unit 2 is increased and maintained at 300-350°C, with a heating rate of 2°C / min. The only product of the in-situ conversion in this process is methanol, and the total amount of methanol is 80% of the total amount of adsorbed carbon dioxide. The methanol produced by the in-situ conversion is stored in a serpentine condenser 41 or directly introduced into a gas chromatograph or other equipment for characterization and analysis.

[0059] The above steps are repeated in this alternating cycle to switch between adsorption and conversion, thereby achieving continuous coupled carbon dioxide capture and conversion into methanol.

[0060] In some embodiments, the composite material 21 is a mixture of NaNO 3 modified MgO and zinc oxide zirconium oxide bimetallic oxide, and the mass ratio of NaNO 3 modified MgO to zinc oxide zirconium oxide bimetallic oxide is 1:4.

[0061] It should be noted that the composite material 21 includes an adsorption active component and a catalytic active component. The adsorption active component is NaNO3-modified MgO, and the catalytic active component is zinc oxide-zirconia bimetallic oxide. The two are combined by physical mixing, and the adsorption and catalytic dual functional working conditions are perfectly matched, and the working performance promotes each other: NaNO3-modified MgO has excellent adsorption capacity for the flue gas conditions of the petrochemical industry, and the regeneration temperature after adsorbing carbon dioxide matches the conversion temperature of zinc oxide-zirconia bimetallic oxide. Zinc oxide-zirconia bimetallic oxide effectively divides NaNO3-modified MgO particles to prevent the agglomeration of carbon dioxide adsorption products; in addition, after carbon dioxide is adsorbed and fixed by MgO, a hydrogen-rich atmosphere is created under hydrogen regeneration conditions, greatly improving the efficiency of carbon dioxide conversion to methanol.

[0062] According to the results of carbon dioxide cyclic adsorption and desorption tests, the composite material 21 can adsorb more than 1 mol / kg of carbon dioxide within one hour, and the saturated adsorption can reach up to 11.4 mol / kg; the carbon dioxide conversion rate is greater than 80%, which is much higher than the current conversion rate of about 25%; and the methanol selectivity is close to 100%.

[0063] Furthermore, MgO was synthesized by a hydrothermal method, NaNO3 modification was achieved by an impregnation method, and zinc oxide and zirconium oxide bimetallic oxides were synthesized by a coprecipitation method.

[0064] In some embodiments, the particle size of NaNO3-modified MgO is 0.2-0.3 μm, and the particle size of zinc oxide-zirconium oxide bimetallic oxide is 0.1-0.2 μm.

[0065] In some embodiments, the molecular ratio of Na to Mg in NaNO3-modified MgO is 1:9.

[0066] In some embodiments, the molar percentage of Zn / Zn+Zr element in the zinc oxide zirconium oxide bimetallic oxide is 13%.

[0067] In some embodiments, the preparation method of NaNO3-modified MgO comprises the following steps:

[0068] P1, dissolving magnesium acetate tetrahydrate and urea in deionized water to obtain a first mixed solution, adjusting the pH value of the first mixed solution to 9.0, and then transferring the first mixed solution to a Teflon autoclave;

[0069] P2, placing a Teflon autoclave in a muffle furnace for heating, and after the reaction of magnesium acetate tetrahydrate and urea is completed, naturally cooling to room temperature, opening the Teflon autoclave, filtering and collecting a white precipitate, and washing and drying the white precipitate to obtain a white powder;

[0070] P3, calcining the white powder in air to obtain MgO;

[0071] P4, dissolving MgO and NaNO3 in ethanol, stirring to obtain a mixed solution, and drying the mixed solution to obtain a dry white powder;

[0072] P5, the dried white powder was calcined in air to obtain NaNO3-modified MgO.

[0073] Further, the preparation method of NaNO3 modified MgO specifically comprises the following steps:

[0074] (1) dissolving 0.08 mol of magnesium acetate tetrahydrate and 0.24 mol of urea in 50 ml of deionized water to obtain a first mixed solution;

[0075] (2) controlling the initial pH value of the first mixed solution in step (1) to 8.2, and adjusting the pH value to 9.0 by adding 25-28% concentrated ammonia water;

[0076] (3) transferring the first mixed solution in step (2) into a 100 ml Teflon autoclave;

[0077] (4) placing the Teflon high-pressure reactor in step (3) in a muffle furnace and heating at 180° C. for 5 hours, and cooling naturally to room temperature after the reaction is completed;

[0078] (5) opening the Teflon autoclave in step (4), collecting the white precipitate by filtration, and washing it with deionized water and anhydrous ethanol;

[0079] (6) washing the white precipitate from step (5) and drying at 60° C. for 4 hours to obtain a white powder;

[0080] (7) calcining the dried white powder in step (6) at 500° C. in air for 5 hours to obtain MgO;

[0081] (8) 1.8 mol MgO and 0.2 mol NaNO3 were dissolved in 100 ml ethanol to obtain a mixed solution;

[0082] (9) stirring the mixed solution in step (8) for 8 hours;

[0083] (10) drying the mixed solution in step (9) at 60° C. for 4 hours to obtain a dry white powder;

[0084] (11) The dried white powder in step (10) was calcined in air at 350° C. for 0.5 h to obtain NaNO 3 -modified MgO.

[0085] In some embodiments, the preparation method of zinc oxide zirconium oxide bimetallic oxide comprises the following steps:

[0086] Q1, dissolving zinc nitrate hexahydrate and zirconium nitrate pentahydrate in deionized water to obtain a second mixed solution,

[0087] Q2, under stirring, adding ammonium carbonate solution to the second mixed solution to form a suspension, heating and stirring, fully reacting, cooling to room temperature, collecting precipitates after filtration, washing and drying the precipitates to obtain white powder;

[0088] Q3, calcining the white powder, and then reducing it by heating in a pure hydrogen atmosphere to obtain zinc oxide and zirconium oxide bimetallic oxides.

[0089] Furthermore, the preparation method of zinc oxide zirconium oxide bimetallic oxide comprises the following steps:

[0090] (1) dissolving 0.6 g of zinc nitrate hexahydrate and 5.8 g of zirconium nitrate pentahydrate in 100 ml of deionized water to obtain a second mixed solution;

[0091] (2) under vigorous stirring, adding 100 ml of an aqueous solution containing 3.06 g of ammonium carbonate to the second mixed solution in step (1) at a flow rate of 3 ml / min to form a suspension;

[0092] (3) stirring the suspension in step (2) at 70° C. for 2 hours to ensure sufficient reaction;

[0093] (4) cooling the suspension after stirring in step (3) to room temperature;

[0094] (5) collecting the precipitate from step (4) by filtration and washing three times with deionized water;

[0095] (6) filtering the precipitate obtained in step (5) and drying it at 110° C. for 4 hours to obtain a white powder;

[0096] (7) calcining the white powder obtained in step (6) at 500° C. in static air for 3 hours;

[0097] (8) The white powder obtained in step (7) is reduced at 320° C. for 1 hour in a pure hydrogen atmosphere to obtain a zinc oxide and zirconium oxide bimetallic oxide.

[0098] In some embodiments, in step S5, the pressure of the back pressure valve 31 is adjusted to 3 MPa, the pressure of the hydrogen introduced is adjusted by the third pressure reducing valve 15 of the hydrogen pipeline, the flow rate of the hydrogen is adjusted to 100 ml / min by the third flow valve 16, and the gas required for pressure boosting is discharged through the channel of the back pressure valve 31.

[0099] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0100] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0101] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0102] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0103] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0104] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A system for coupling carbon dioxide capture and in-situ methanolization, characterized in that: include: A gas delivery and switching unit, the gas delivery and switching unit comprising a nitrogen pipeline, a flue gas pipeline and a hydrogen pipeline, the nitrogen pipeline, the flue gas pipeline and the hydrogen pipeline are connected in parallel to the main pipeline; An adsorption and conversion unit, the adsorption and conversion unit is connected to the main pipeline, the adsorption and conversion unit is filled with a composite material with adsorption and catalytic dual functions to complete carbon dioxide adsorption and in-situ methanolization, and a temperature regulating mechanism is provided in the adsorption and conversion unit; A product collection unit, the product collection unit is connected downstream of the adsorption and conversion unit to collect the generated methanol; A pressure control unit is connected between the adsorption and conversion unit and the product collection unit, and the pressure control unit includes a back pressure valve and a solenoid valve connected to the main pipeline.

2. The system for coupling carbon dioxide capture and in-situ methanolization according to claim 1, characterized in that: The product collection unit comprises a serpentine condenser and a collection tank, wherein the serpentine condenser is arranged at the feed inlet of the collection tank.

3. The system for coupling carbon dioxide capture and in-situ methanolization according to claim 1, characterized in that: The nitrogen pipeline is connected with a first pressure reducing valve and a first flow valve, the flue gas pipeline is connected with a second pressure reducing valve and a second flow valve, and the hydrogen pipeline is connected with a third pressure reducing valve and a third flow valve.

4. A method for coupling carbon dioxide capture and in-situ methanolization, characterized in that: Using the system according to any one of claims 1 to 3, comprising the following steps: S1, nitrogen is introduced into the adsorption and conversion unit, the temperature in the adsorption and conversion unit is raised to 300-350° C. and maintained for a period of time to pretreat the composite material, and the pretreated gas is discharged through the channel of the solenoid valve; S2, introducing flue gas into the adsorption and conversion unit, the composite material in the adsorption and conversion unit adsorbs carbon dioxide in the flue gas, and the adsorbed low-carbon flue gas is discharged through the channel of the solenoid valve; S3, introducing nitrogen into the adsorption and conversion unit for purging, and the purged gas is discharged through the channel of the solenoid valve; S4, introducing hydrogen into the adsorption and conversion unit for purging, and the purged gas is discharged through the channel of the solenoid valve; S5, close the channel of the solenoid valve, adjust the back pressure valve and the pressure of hydrogen, introduce hydrogen into the adsorption and conversion unit, raise the temperature in the adsorption and conversion unit to 300-350°C, and collect methanol generated by the reaction of hydrogen and carbon dioxide into the product collection unit.

5. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 4, characterized in that: The composite material is a mixture of NaNO3-modified MgO and zinc oxide-zirconium oxide bimetallic oxide, and the mass ratio of NaNO3-modified MgO to zinc oxide-zirconium oxide bimetallic oxide is 1:

4.

6. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 5, characterized in that: The particle size of the NaNO3-modified MgO is 0.2-0.3 μm, and the particle size of the zinc oxide-zirconium oxide bimetallic oxide is 0.1-0.2 μm.

7. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 6, characterized in that: In the NaNO3-modified MgO, the molecular ratio of Na to Mg is 1:

9.

8. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 5, characterized in that: The preparation method of NaNO3-modified MgO comprises the following steps: P1, dissolving magnesium acetate tetrahydrate and urea in deionized water to obtain a first mixed solution, adjusting the pH value of the first mixed solution to 9.0, and then transferring it to a Teflon reactor; P2, placing a Teflon reactor in a muffle furnace for heating, and after the reaction of magnesium acetate tetrahydrate and urea is completed, naturally cooling to room temperature, opening the Teflon reactor, filtering and collecting a white precipitate, and washing and drying the white precipitate to obtain a white powder; P3, calcining the white powder in air to obtain MgO; P4, dissolving MgO and NaNO3 in ethanol, stirring to obtain a mixed solution, and drying the mixed solution to obtain a dry white powder; P5, the dried white powder was calcined in air to obtain NaNO3-modified MgO.

9. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 4, characterized in that: The preparation method of the zinc oxide zirconium oxide bimetallic oxide comprises the following steps: Q1, dissolving zinc nitrate hexahydrate and zirconium nitrate pentahydrate in deionized water to obtain a second mixed solution, Q2, under stirring, adding ammonium carbonate solution to the second mixed solution to form a suspension, heating and stirring, fully reacting, cooling to room temperature, collecting precipitates after filtration, washing and drying the precipitates to obtain white powder; Q3, calcining the white powder, and then reducing it by heating in a pure hydrogen atmosphere to obtain zinc oxide and zirconium oxide bimetallic oxides.

10. The method for coupling carbon dioxide capture and in-situ methanolization according to claim 4, characterized in that: In step S5, the pressure of the back pressure valve is adjusted to 3MPa, the pressure of the hydrogen introduced is adjusted by the third pressure reducing valve of the hydrogen pipeline, the flow rate of the hydrogen is adjusted to 100ml / min by the third flow valve, and the gas required for pressure increase is discharged through the channel of the back pressure valve.

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