Carbon dioxide separation, capture and utilization system and carbon dioxide separation, capture and utilization method

Abstract

To provide an energy-efficient carbon dioxide separation, recovery and utilization system and carbon dioxide separation, recovery and utilization method.SOLUTION: A carbon dioxide separation, recovery and utilization system comprises: a regeneration unit for generating a carbon dioxide-containing gas from a solid material that has absorbed or adsorbed carbon dioxide and regenerating the solid material; a reactor in which the carbon dioxide-containing gas generated by the regeneration unit and hydrogen are introduced and at least one kind selected from the group consisting of a synthetic fuel, methane and methanol and steam are generated; and a steam introduction line for introducing at least a part of the steam generated by the reactor into the regeneration unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide separation, capture and utilization system and a carbon dioxide separation, capture and utilization method. [Background technology]

[0002] In recent years, there has been an increasing need to reduce greenhouse gas emissions, and there is an urgent need to develop technology to separate and capture carbon dioxide from exhaust gases generated at power plants, steel mills, cement plants, and other facilities.

[0003] For example, Patent Document 1 teaches a method for separating and capturing carbon dioxide, which includes the steps of contacting a particulate carbon dioxide adsorbent with a gas to be treated that contains carbon dioxide, thereby causing the carbon dioxide contained in the gas to be treated to be adsorbed onto the carbon dioxide adsorbent, and contacting the carbon dioxide adsorbent that has adsorbed carbon dioxide with superheated steam, thereby causing carbon dioxide to be desorbed from the carbon dioxide adsorbent, thereby regenerating the carbon dioxide adsorbent and recovering the desorbed carbon dioxide, wherein the saturation temperature of the superheated steam brought into contact with the carbon dioxide adsorbent is equal to or lower than the temperature of the carbon dioxide adsorbent that contacts the superheated steam, and the regenerated carbon dioxide adsorbent is reused for adsorbing carbon dioxide without undergoing a drying step.

[0004] On the other hand, Patent Document 2 teaches a method for producing methanol, which includes the steps of: supplying a raw material gas containing carbon dioxide and hydrogen to a first space of a separation membrane reactor having a first space on the non-permeation side, a water vapor separation membrane, a second space on the permeation side, and a catalyst disposed in the first space, and proceeding with a conversion reaction of the raw material gas to methanol by the action of the catalyst; circulating a sweep gas through the second space to remove reaction heat generated with the conversion reaction and to allow water vapor, which is a by-product of the conversion reaction and has permeated the water vapor separation membrane, to flow out from the second space; cooling a non-permeation fluid containing methanol produced by the conversion reaction and an unreacted gas, condensing the methanol to separate it from the unreacted gas; and circulating the unreacted gas to the first space. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020-90806 Brochure [Patent Document 2] JP 2018-8940 A Summary of the Invention [Problem to be solved by the invention]

[0006] To provide a carbon dioxide separation, capture and utilization system and a method for separation, capture and utilization that are highly energy efficient. [Means for solving the problem]

[0007] One aspect of the present invention relates to a carbon dioxide separation, capture and utilization system comprising: a regeneration unit that generates a gas containing carbon dioxide from a solid material that has absorbed or adsorbed carbon dioxide and regenerates the solid material; a reactor into which the gas containing carbon dioxide generated in the regeneration unit and hydrogen are introduced and which generates at least one selected from the group consisting of synthetic fuel, methane and methanol and water vapor; and a water vapor inlet line that introduces at least a portion of the water vapor generated in the reactor into the regeneration unit.

[0008] Another aspect of the present invention relates to a method for separating, capturing and utilizing carbon dioxide, comprising: a preparation step of preparing a solid material that has absorbed or adsorbed carbon dioxide; a regeneration step of generating a gas containing carbon dioxide from the solid material that has absorbed or adsorbed carbon dioxide and regenerating the solid material; and a reaction step of reacting the gas containing carbon dioxide with hydrogen to generate at least one selected from the group consisting of synthetic fuel, methane and methanol, and water vapor, wherein the regeneration step includes contacting at least a portion of the water vapor with the solid material that has absorbed or adsorbed carbon dioxide. Effect of the Invention

[0009] According to the present invention, since the water vapor generated in the exothermic hydrogenation reaction of carbon dioxide is utilized to regenerate solid materials, it is possible to provide a carbon dioxide separation, capture and utilization system and a method for separation, capture and utilization that are excellent in energy efficiency. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of an example of a carbon dioxide separation, capture and utilization system according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a conceptual diagram showing the configuration of a water vapor separation membrane of a membrane reactor provided in the system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An example of a carbon dioxide separation and capture system according to an embodiment of the present invention is a system with excellent energy utilization efficiency that combines a carbon dioxide separation and capture system with a hydrogenation reaction of the separated and captured carbon dioxide. The construction of carbon dioxide separation and capture systems is being considered for use in thermal power plants, cement plants, steelworks, chemical plants, and the like. In addition, development is underway for Fischer-Tropsch (FT) synthesis, which synthesizes synthetic fuels by reducing captured carbon dioxide, and technology for synthesizing methane, methanol, and the like by hydrogenating carbon dioxide. Direct air capture (DAC), which captures carbon dioxide from the atmosphere and uses it for business purposes, is also attracting attention.

[0012] A promising method for carbon dioxide separation and capture systems is to separate carbon dioxide by absorbing or adsorbing it onto a solid material. Solid materials have durability suitable for repeated use. The solid material that has absorbed or adsorbed carbon dioxide is regenerated by contacting it with steam in the regeneration section and can be used repeatedly. In the regeneration section, the solid material is heated by steam, and gas containing carbon dioxide is extracted and the solid material is regenerated.

[0013] When steam is introduced into the regeneration section, the carbon dioxide partial pressure (carbon dioxide concentration) becomes significantly lower than the carbon dioxide partial pressure (carbon dioxide concentration) at the surface of the solid material. This difference in carbon dioxide partial pressure acts as a driving force to diffuse the carbon dioxide absorbed or adsorbed in the solid material into the steam. This causes the carbon dioxide to leave the solid material, and the solid material is regenerated.

[0014] The water vapor may be superheated water vapor. Since superheated water vapor has a lower relative humidity than saturated water vapor, condensed water is less likely to adhere to the surface of the solid material. The inside of the regeneration unit may be a reduced pressure atmosphere. In the reduced pressure atmosphere, the temperature of the superheated water vapor is less than 100°C (for example, 60 to 80°C). The temperature of the superheated water vapor may be controlled to be equal to or lower than the temperature of the solid material, but may be higher than the temperature of the solid material. The temperature of the superheated water vapor may be, for example, 20 to 30°C higher than the temperature of the solid material.

[0015] The saturation temperature of the superheated steam may be equal to or lower than the temperature of the solid material. In this case, there is no need to dry the solid material after regeneration, since there is no condensation of steam on the surface of the solid material or the amount of condensation is only slightly suppressed. Eliminating the need to dry the solid material also makes it easier to reduce the size of the carbon dioxide capture and utilization system and the cost of equipment.

[0016] The solid material may be, for example, a porous material carrying an amine compound, a honeycomb, etc., but is not particularly limited thereto. The porous material may be activated carbon, activated alumina, silica, silica alumina, titania, zirconia, cordierite, etc.

[0017] The gas containing carbon dioxide produced in the regeneration section is sent to a reactor together with hydrogen, and reacts with hydrogen in the reactor to produce a target product and steam. This reaction is an exothermic reaction, and steam can be used as a heat source. In the reaction between carbon dioxide and hydrogen, at least one selected from the group consisting of synthetic fuel, methane, and methanol is produced as a target product. Synthetic fuel refers to fuel that is liquid at normal temperature and pressure, such as gasoline with 5 to 12 carbon atoms and diesel with 12 to 18 carbon atoms, and among these, liquid hydrocarbon fuels mainly composed of hydrocarbons with 5 to 10 carbon atoms are preferred.

[0018] In the carbon dioxide separation, capture, and utilization system according to this embodiment, water vapor that can be used as a heat source is extracted from the reactor, and at least a part of the water vapor is introduced into the regeneration section. That is, the carbon dioxide separation, capture, and utilization system according to this embodiment is provided with a water vapor introduction line that introduces at least a part of the water vapor generated in the reactor into the regeneration section.

[0019] The first advantage of this embodiment is that it is energy efficient because the heat-storing steam generated by the hydrogenation reaction of carbon dioxide can be used to regenerate the solid material. In the regeneration section, the solid material that has absorbed or adsorbed carbon dioxide is efficiently heated by the steam, promoting the desorption of carbon dioxide from the solid material. This makes it possible to reduce the energy required to separate and capture carbon dioxide.

[0020] Here, the reactor is preferably a membrane reactor having a first space on the non-permeation side into which the gas containing carbon dioxide and hydrogen are introduced, a water vapor separation membrane, and a second space on the permeation side. The water vapor separation membrane is disposed so as to separate the first space from the second space. The water vapor separation membrane is, for example, an inorganic composite, and has a porous support and an inorganic membrane supported thereon.

[0021] Examples of the inorganic membrane include a zeolite membrane, a silica membrane, and a carbon membrane. The thickness of the inorganic membrane is, for example, 0.5 μm to 10 μm. The porous support is, for example, a cylindrical body having a first surface and a second surface, the first surface and the second surface being connected by pores, the first space being connected to the pores at the first surface, and the second space being connected to the pores at the second surface. Examples of the material of the porous support include silica, alumina, zirconia, cordierite, and stainless steel (SUS).

[0022] A catalyst that promotes the hydrogenation reaction of carbon dioxide may be placed in the first space. For example, the catalyst may be filled in the first space, or the catalyst may be supported on the first space side of the water vapor separation membrane. Examples of the catalyst that promotes the hydrogenation reaction of carbon dioxide include iron, copper, palladium, zinc oxide, zirconia, gallium oxide, and composites thereof.

[0023] In the first space on the non-permeation side of the membrane reactor, the hydrogenation reaction of carbon dioxide proceeds, producing the target product and water vapor. For example, the reaction formula for FT synthesis is as follows: The target product (e.g., liquid hydrocarbons) is recovered from the first space. CO2+H2⇔CO+H2O (2n+1)H2+nCO⇒C n H 2n+2 +nH2O

[0024] On the other hand, the generated water vapor permeates the water vapor separation membrane and moves to the second space on the permeation side. The second advantage of this embodiment is that the by-product water vapor moves to the second space and is removed from the first space, promoting the reaction between carbon dioxide and hydrogen through equilibrium shift, thereby improving the carbon dioxide conversion rate.

[0025] However, because water and hydrogen have similar molecular sizes, some of the hydrogen introduced as a raw material into the first space also permeates the water vapor separation membrane and moves to the second space. In other words, the water vapor extracted from the second space contains hydrogen. Hydrogen is a valuable resource for the efficient operation of the carbon dioxide utilization system, and it is desirable to reuse it.

[0026] The third advantage of this embodiment is that the hydrogen that inevitably moves to the second space is introduced into the steam introduction line together with the heat-storing steam, and then introduced into the regeneration section. In this case, the hydrogen introduced from the second space is mixed into the gas containing carbon dioxide generated in the regeneration section. The hydrogen mixed into the gas containing carbon dioxide is sent to the reactor together with the carbon dioxide, and is reused as a raw material. This makes it possible to extremely increase the effective utilization rate of hydrogen.

[0027] The water vapor permeation rate of the water vapor separation membrane is preferably as high as possible, but the amount of hydrogen that migrates to the second space is inevitably large. However, the hydrogen that migrates to the second space is introduced into the regeneration section via the water vapor introduction line and is finally returned to the reactor, so the loss of hydrogen is limited. The water vapor permeation rate of the water vapor separation membrane is, for example, 1×10 -7 mol / (s Pa m 2 ) or more is acceptable, 1×10 -6 mol / (s Pa m 2 ) may be exceeded.

[0028] The carbon dioxide separation, capture and utilization system according to this embodiment may further include a dehydration section that removes water vapor from the gas containing carbon dioxide before it is introduced into the reactor. The dehydration section may have a function of cooling the gas containing carbon dioxide, for example. By cooling, the water vapor is liquefied, and gaseous carbon dioxide and hydrogen are separated and recovered. The mixed gas of the separated and recovered carbon dioxide and hydrogen is introduced into the reactor. The configuration of the dehydration section is not particularly limited.

[0029] The carbon dioxide separation, capture and utilization system according to this embodiment may further include a carbon dioxide capture section that brings the gas to be treated, which contains carbon dioxide, into contact with a solid material to absorb or adsorb carbon dioxide into the solid material. The solid material that has absorbed or adsorbed carbon dioxide in the carbon dioxide capture section is supplied to the regeneration section. This makes it possible to construct a carbon dioxide separation, capture and utilization system that has excellent energy utilization efficiency and combines a carbon dioxide separation and capture system with the production of a target product using the separated and captured carbon dioxide as a raw material.

[0030] The carbon dioxide capture section may also serve as the regeneration section. That is, the regeneration section may have the function of the carbon dioxide capture section, or the carbon dioxide capture section may have the function of the regeneration section. For example, after carbon dioxide is adsorbed by a solid material filled in the carbon dioxide capture section, water vapor may be introduced into the carbon dioxide capture section, and the carbon dioxide capture section may be used as the regeneration section.

[0031] The gas to be treated is generated in large quantities as a gas containing carbon dioxide in, for example, thermal power plants, cement plants, steelworks, chemical plants, etc. For example, in steelworks, gas containing a high concentration of carbon dioxide is generated as blast furnace gas or converter gas. The gas to be treated may be biomass combustion gas, or the atmosphere, air in a closed space, or air in an indoor space.

[0032] Hereinafter, an example of the carbon dioxide separation, capture and utilization system and separation, capture and utilization method according to the present embodiment will be specifically described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of an example of the carbon dioxide separation, capture and utilization system. Fig. 2 is a conceptual diagram showing the configuration of a water vapor separation membrane.

[0033] The carbon dioxide separation, capture and utilization system 100 comprises a membrane reactor 10 and a regeneration section 20. The regeneration section 20 is filled with a solid material that has absorbed or adsorbed carbon dioxide. When steam, which serves as a heat source, is introduced into the regeneration section 20 and the solid material is heated with the steam, carbon dioxide is released from the solid material. As a result, a gas containing carbon dioxide and steam is generated in the regeneration section. At the same time, the solid material is regenerated by the carbon dioxide being extracted.

[0034] The gas containing carbon dioxide generated in the regeneration section 20 is introduced into the membrane reactor 10 from the inlet section 12 of the membrane reactor 10 via the product gas inlet lines L21 and L22. A dehydration section 50 is provided downstream of the product gas inlet lines L21 and L22. In the dehydration section 50, water vapor used for heating the solid material is removed from the gas containing carbon dioxide before it is introduced into the membrane reactor 10. In addition, hydrogen is introduced into the membrane reactor 10 from the inlet section 12 via a hydrogen inlet line L5.

[0035] The membrane reactor 10 comprises a first space S1 on the non-permeation side, a water vapor separation membrane 11, and a second space S2 on the permeation side. A gas containing carbon dioxide generated in the regeneration section 20 and hydrogen are introduced into the first space S1 from an introduction section 12. The water vapor separation membrane 11 is an inorganic composite comprising a porous support 112 and an inorganic membrane 111 supported by the porous support 112. The porous support 112 is a porous cylindrical body having an outer peripheral surface (first surface) and an inner peripheral surface (second surface), and the first surface and the second surface are connected by pores. The first space S1 communicates with the pores at the first surface. The second space S2 communicates with the pores at the second surface. The first space S1 is filled with carrier particles P carrying a catalyst that promotes the hydrogenation reaction of carbon dioxide.

[0036] The target product (at least one selected from the group consisting of synthetic fuel, methane, and methanol) produced by the reaction in the first space S1 is sent together with the unreacted gas from the discharge section 13 to the separation section 40. In the separation section 40, the target product (e.g., methanol) and the unreacted gas are separated. The separated unreacted gas is sent to the introduction section 12 of the membrane reactor 10 via the unreacted gas recovery line L4 and reused.

[0037] Meanwhile, at least a part of the water vapor generated in the first space S1 and a part of the hydrogen introduced into the first space S1 permeate the water vapor separation membrane 11 and move to the second space S2. The water vapor and hydrogen in the second space S2 are then sent to the regeneration section 20 via the water vapor introduction line L1. The heat of the water vapor and hydrogen is then used as at least a part of the energy required to regenerate the solid material that has absorbed or adsorbed carbon dioxide in the regeneration section 20. Of the carbon dioxide-containing gas generated in the regeneration section 20, the water vapor is removed in the dehydration section 50, and the carbon dioxide and hydrogen are sent to the first space S1 of the membrane reactor 10.

[0038] The regeneration section 20 can also be used as a carbon dioxide capture section 30 (hereinafter referred to as the "capture section 30"). The regeneration section 20 or the capture section 30 is filled with a solid material that reversibly absorbs or adsorbs carbon dioxide. During a predetermined period, water vapor generated in the membrane reactor 10 is introduced into the regeneration section 20 (capture section 30) through the water vapor introduction line L1. During another period, a gas to be treated containing carbon dioxide is introduced into the capture section 30 (regeneration section 20) through the gas to be treated introduction line L3, and the carbon dioxide is separated and captured. Gas containing components other than carbon dioxide is released or transferred to the outside of the system through the discharge line Lout.

[0039] 1, the regeneration section 20 into which steam and hydrogen are introduced is switched by operating the first branch section B1. Also, the capture section 30 into which the gas to be treated is introduced is switched by operating the second branch section B2. By installing multiple structures that serve as both the regeneration section 20 and the capture section 30 and that accommodate solid materials, it is possible to constantly ensure that the regeneration section 20 and the capture section 30 are available within one system.

[0040] When superheated steam is used as the water vapor, the relative humidity is lower than that of saturated steam, so that the amount of condensed water adhering to the surface of the solid material is reduced. The pressure of the superheated steam inside the regenerator 20 may be equal to or lower than the saturated steam pressure at the temperature of the solid material to be contacted with the superheated steam. The saturation temperature of the superheated steam may be set to a temperature about 10 to 15°C lower than the temperature of the solid material to be contacted with the superheated steam. For example, when the temperature of the solid material is about 60°C, superheated steam at about 70°C, which has a saturation temperature of about 50°C, may be used. [Industrial Applicability]

[0041] The carbon dioxide separation, capture and utilization system and the carbon dioxide separation, capture and utilization method according to the present invention are suitable for the case where the carbon dioxide separation, capture and utilization system is operated in combination with a carbon dioxide hydrogenation reaction in, for example, thermal power plants, cement plants, steelworks, chemical plants, etc. Furthermore, since the carbon dioxide separation, capture and utilization system and the carbon dioxide separation, capture and utilization method according to the present invention are highly energy efficient, they are also suitable for the case where carbon dioxide captured in DAC, closed spaces, indoor spaces, etc. is effectively utilized. [Explanation of symbols]

[0042] 100: Carbon dioxide capture and utilization system 10: Membrane reactor 11: Water vapor separation membrane 111: Inorganic membrane 112: Porous support 12: Introduction 13: Discharge section 20: Playback section 30: Carbon dioxide capture section 40: Separation part 50: Dehydration section L1: Water vapor introduction line L21, L22: Produced gas introduction line L3: Processing gas introduction line L4: Unreacted gas recovery line L5: Hydrogen introduction line Lout: discharge line S1: 1st space S2:Second space P: Catalyst particles B1: First branch B2: Second branch

Claims

1. a regeneration unit that generates a gas containing carbon dioxide from a solid material that has absorbed or adsorbed carbon dioxide and regenerates the solid material; A reactor into which the gas containing the carbon dioxide generated in the regeneration unit and hydrogen are introduced and which generates at least one selected from the group consisting of synthetic fuel, methane, and methanol, and water vapor; a steam introduction line for introducing at least a portion of the steam generated in the reactor into the regeneration section; A carbon dioxide separation, capture and utilization system equipped with the above.

2. The reactor includes a first space on a non-permeation side into which the carbon dioxide-containing gas and the hydrogen are introduced, a water vapor separation membrane, and a second space on a permeation side; 2. The carbon dioxide separation, capture and utilization system according to claim 1, wherein the water vapor and the hydrogen which have permeated the water vapor separation membrane are introduced from the second space into the water vapor introduction line.

3. The carbon dioxide separation and capture system according to claim 2 , wherein the water vapor separation membrane is an inorganic composite comprising a porous support and an inorganic membrane supported on the porous support.

4. The carbon dioxide separation and capture / utilization system according to any one of claims 1 to 3, further comprising a dehydration section that removes the water vapor from the gas containing carbon dioxide before it is introduced into the reactor.

5. Further, a carbon dioxide recovery section is provided for contacting a gas to be treated containing carbon dioxide with the solid material to absorb or adsorb the carbon dioxide in the solid material, The carbon dioxide separation and capture and utilization system according to any one of claims 1 to 4, wherein the solid material that has absorbed or adsorbed the carbon dioxide in the carbon dioxide capture section is supplied to the regeneration section.

6. A preparation step of preparing a solid material that has absorbed or adsorbed carbon dioxide; a regeneration step of generating a gas containing the carbon dioxide from the solid material that has absorbed or adsorbed the carbon dioxide and regenerating the solid material; a reaction step of reacting the carbon dioxide-containing gas with hydrogen to generate at least one selected from the group consisting of synthetic fuel, methane, and methanol, and water vapor; having The regeneration step comprises contacting at least a portion of the water vapor with a solid material that has absorbed or adsorbed the carbon dioxide.

7. In the reaction step, the gas containing carbon dioxide and the hydrogen are supplied to a first space of a reactor having a non-permeation side, a water vapor separation membrane, and a second space of a permeation side, and the water vapor and the hydrogen that have permeated the water vapor separation membrane are extracted from the second space, 7. The method for separating, capturing and utilizing carbon dioxide according to claim 6, wherein in the regeneration step, the water vapor and the hydrogen extracted from the second space are brought into contact with a solid material that has absorbed or adsorbed the carbon dioxide.

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