Fuel gas heating method and raw material production method

Abstract

To provide a method for increasing the heat of a fuel gas by which the separation of carbon dioxide in the fuel gas and the increase of heat can efficiently be carried out, and to provide a method for producing a raw material.SOLUTION: A method for increasing heat of a fuel gas for separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide and increasing heat thereof comprises: a fuel gas introduction step for introducing the fuel gas into an introduction space section of a separation mechanism having the introduction space section and a sweeping space section separated by a separation membrane; a gas separation step for causing carbon dioxide contained in the fuel gas to pass through the separation membrane and move from the introduction space section to the sweeping space section; and an increased heat gas derivation step for deriving, as an increased heat gas, the fuel gas from which the carbon dioxide has been separated in the gas separation step, from the introduction space section. And a delivery gas delivery step of delivering the sweep gas and the carbon dioxide as a delivery gas from the swept space part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for increasing the heat of fuel gas by separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide, and a method for producing a raw material. [Background technology]

[0002] By-product gases generated in steelworks include combustible gases. For example, blast furnace gas generated from a blast furnace contains four main components: nitrogen, carbon monoxide, carbon dioxide, and hydrogen. Specifically, blast furnace gas contains approximately 50% nitrogen, 20-25% carbon monoxide and carbon dioxide, and a few percent hydrogen. Converter gas generated from a converter contains five main components: nitrogen, carbon monoxide, carbon dioxide, hydrogen, and oxygen. Specifically, it contains more than 70% carbon monoxide, approximately 15% carbon dioxide, and a few percent hydrogen, nitrogen, and oxygen. For this reason, these by-product gases are used as fuel in each factory within the steelworks. In other words, by-product gases are used in each factory as an example of a fuel gas containing combustible gas and carbon dioxide.

[0003] However, in recent years, reducing carbon dioxide emissions, which are considered to be the main cause of global warming, has become an important issue. Therefore, in order to reduce carbon dioxide emissions into the atmosphere, attention has been focused on technologies that separate and capture carbon dioxide from fuel gases that contain carbon dioxide, and then use the captured carbon dioxide effectively (Carbon Capture and Utilization: CCU) or store it underground (Carbon Capture and Storage: CCS).

[0004] Furthermore, by-product gases (blast furnace gas, converter gas) that can be used in each factory within a steelworks also contain many non-combustible gases, such as nitrogen and carbon dioxide. The non-combustible gases contained in the by-product gas have no calorific value. This reduces the amount of heat that can be retained per unit volume of the by-product gas. When using the by-product gas as fuel in each factory within a steelworks, a significant amount of energy is consumed to heat the contained non-combustible gases. For the same reason, even when using fuel gases other than by-product gases (containing non-combustible gases), a significant amount of energy is required. Carbon dioxide, in particular, consumes a large amount of energy because it has a higher molar heat capacity at constant pressure than nitrogen, carbon monoxide, and hydrogen.

[0005] That is, when by-product gas containing carbon dioxide is used as fuel gas in each plant in a steelworks, separating the carbon dioxide in advance can reduce the energy consumption for heating the non-combustible carbon dioxide. This also has the effect of increasing the heat of the fuel gas, which can contribute to improving the energy utilization efficiency in the steelworks and reducing carbon dioxide emissions. In light of this situation, methods for increasing the heat of fuel gas by separating carbon dioxide have been widely studied.

[0006] For example, Patent Document 1 discloses a method for separating and recovering carbon dioxide and nitrogen with the aim of increasing the calorific value of blast furnace gas and converter gas that can be used in each plant within a steelworks. Specifically, the method discloses a pre-treatment process for removing dust, sulfur content, and mist, and then a carbon dioxide separation process using an absorption method using amine, ammonia, or the like, an adsorption method (PSA method, TSA method) using activated carbon or zeolite, or a membrane separation method. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-108241 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the method disclosed in Patent Document 1, a preliminary treatment step of the fuel gas containing carbon dioxide must be performed prior to the carbon dioxide separation step based on a membrane separation method or the like. This makes it difficult to continuously and quickly perform the separation and heating of carbon dioxide. Therefore, when using fuel gas containing carbon dioxide, it is necessary to continuously supply it to each factory in the steelworks, so it has been necessary to improve the efficiency of the separation and heating of carbon dioxide.

[0009] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a method for increasing the heat of fuel gas and a method for producing raw material that can efficiently separate carbon dioxide from fuel gas and increase its heat. [Means for solving the problem]

[0010] [1] A method for increasing the heat of fuel gas by separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide and increasing its heat, the method comprising: a fuel gas introduction step of introducing the fuel gas into an introduction space of a separation mechanism having an introduction space and a sweep space separated by a separation membrane; a gas separation step of causing carbon dioxide contained in the fuel gas to permeate the separation membrane and move from the introduction space to the sweep space; a heat-increasing gas delivery step of delivering the fuel gas from which carbon dioxide has been separated in the gas separation step, from the introduction space as a heat-increasing gas; a sweep gas delivery step of delivering the sweep gas into the sweep space; and a delivery gas delivery step of delivering the sweep gas and carbon dioxide from the sweep space as delivery gases. [2] The method for increasing the heat of fuel gas according to [1], wherein the sweep gas contains hydrogen. [3] The method for increasing the heat of fuel gas according to [1] or [2], wherein the fuel gas is a by-product gas generated from a blast furnace or a converter. [4] A method for producing a raw material, which uses the gas delivered by the method for increasing the temperature of a fuel gas according to [1] or [2] as a raw material gas for a carbon dioxide hydrogenation reaction. [5] The raw material production method according to [4], wherein the hydrogenation reaction is a methanol synthesis reaction. [6] The raw material production method according to [4], wherein the hydrogenation reaction is a methane synthesis reaction. [7] The method for increasing the heat of fuel gas according to [1], wherein the sweep gas is exhaust gas generated by using the heat-increasing gas in a combustion section. [8] The method for increasing the heat of fuel gas according to [7], wherein the pressure of the fuel gas is 15 kPa or more higher than the pressure of the sweep gas. [9] The method for increasing the heat of fuel gas according to [7] or [8], wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

[10] The method for increasing the heat of fuel gas according to [7] or [8], wherein an auxiliary gas is added to the sweep gas and then fed in the sweep gas feeding step.

[11] The method for increasing the heat of fuel gas according to

[10] , wherein the auxiliary gas contains hydrogen.

[12] The method for increasing the heat of fuel gas according to

[10] , wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

[13] A method for producing a raw material, comprising using the gas delivered by the method for increasing the temperature of a fuel gas according to

[10] or

[11] as a raw material gas for a carbon dioxide hydrogenation reaction.

[14] The raw material production method according to

[13] , wherein the hydrogenation reaction is a methanol synthesis reaction.

[15] The raw material production method according to

[13] , wherein the hydrogenation reaction is a methane synthesis reaction.

[16] A method for increasing the heat of fuel gas by separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide and increasing its heat, the method comprising: a fuel gas introduction step of introducing the fuel gas into a first introduction space of a first separation mechanism having a first introduction space and a first sweep space separated by a first separation membrane; a first gas separation step of causing carbon dioxide contained in the fuel gas to permeate through the first separation membrane and move from the first introduction space to the first sweep space; a first heat-increasing gas discharge step of discharging the fuel gas from which carbon dioxide has been separated in the first gas separation step as a first heat-increasing gas from the first introduction space; a heat-increasing gas use step of using the first heat-increasing gas discharged in the first heat-increasing gas discharge step in a combustion section; and a first sweeping gas supply step of supplying exhaust gas generated in the heat-increasing gas use step to the first sweeping space as a first sweeping gas. a first delivery gas introducing step of introducing the first delivery gas into a second introduction space of a second separation mechanism having a second introduction space and a second sweep space separated by a second separation membrane; a second gas separation step of transferring carbon dioxide contained in the first delivery gas from the second introduction space to the second sweep space by permeating the second separation membrane; a second heat-increasing gas discharging step of discharging the first delivery gas from which carbon dioxide has been separated in the second gas separation step, as a second heat-increasing gas, from the second introduction space; a second sweep gas introducing step of introducing the second sweep gas into the second sweep space; and a second delivery gas discharging step of discharging the second sweep gas and the carbon dioxide from the second sweep space as the second delivery gas.

[17] The method for increasing the heat of fuel gas according to

[16] , wherein the second sweep gas contains hydrogen.

[18] The method for increasing the heat of fuel gas according to

[16] or

[17] , wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

[19] A method for producing a raw material, wherein the second delivered gas delivered by the method for increasing the temperature of a fuel gas according to

[16] or

[17] is used as a raw material gas for a carbon dioxide hydrogenation reaction.

[20] The raw material production method according to

[19] , wherein the hydrogenation reaction is a methanol synthesis reaction.

[21] The raw material production method according to

[19] , wherein the hydrogenation reaction is a methane synthesis reaction. [Effects of the Invention]

[0011] According to the present invention, separation of carbon dioxide from fuel gas and heat generation can be efficiently carried out. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a fuel gas heat increasing device according to a first embodiment. [Figure 2] FIG. 10 is a diagram showing an example of a schematic configuration of a fuel gas heating device according to a second embodiment. [Figure 3] FIG. 10 is a diagram showing an example of a schematic configuration of a fuel gas heating device according to a third embodiment. [Figure 4] FIG. 10 is a diagram showing an example of a schematic configuration of a fuel gas heating device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described. In the following description, "fuel gas" refers to a gas containing a combustible gas and carbon dioxide. "By-product gas" refers to blast furnace gas and converter gas generated in a steelworks. "Permeation gas" refers to a gas that has permeated a separation membrane in a separation mechanism of a carbon dioxide separation device. "Heated gas" refers to a gas that has been heated without permeating a separation membrane in a separation mechanism. "Sweep gas" refers to a gas that sweeps the permeation gas that has permeated a separation membrane in a separation mechanism. "Delivery gas" collectively refers to the permeation gas and sweep gas delivered from the separation mechanism. In all of the embodiments described below, an embodiment in which "by-product gas" is used as an example of "fuel gas" will be described.

[0014] First Embodiment A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a schematic configuration of a fuel gas heat booster 1 according to the first embodiment. As shown in FIG. 1, the fuel gas heat booster 1 according to the first embodiment includes a separation mechanism 10 and a pipe 50. The separation mechanism 10 includes an introduction space 11, a sweep space 12, and a separation membrane 13. The pipe 50 includes a pipe 50a for feeding a by-product gas E, a pipe 50b for feeding a heat booster gas B1, a pipe 50c for feeding a sweep gas F11, and a pipe 50d for feeding a delivery gas P11.

[0015] The separation membrane 13 has a property of high permeation selectivity for carbon dioxide compared to hydrogen and carbon monoxide. Various types of separation membranes, such as inorganic membranes and organic membranes, may be used as the separation membrane 13. When an inorganic membrane is used as the separation membrane 13, permeation selectivity can be exhibited due to its high affinity for carbon dioxide. For the inorganic membrane, DDR-type zeolite or CHA-type zeolite may be used. Furthermore, when an organic membrane is used as the separation membrane 13, permeation selectivity for carbon dioxide can be exhibited due to differences in solubility and diffusibility in polymers. For the organic membrane, a polymer such as polyimide or cellulose acetate may be used.

[0016] 1, a method for increasing the heat of fuel gas is performed by separating carbon dioxide from by-product gas E. Specifically, first, a fuel gas introduction step is performed in which by-product gas E is introduced into an introduction space 11 of a separation mechanism 10 having an introduction space 11 and a sweep space 12 separated by a separation membrane 13. The by-product gas E is sent through a by-product gas pipe M and may be compressed by a compressor N before being introduced.

[0017] Next, a gas separation step is performed in which carbon dioxide contained in the by-product gas E is passed through the separation membrane 13 and transferred from the introduction space 11 to the sweep space 12. By separating carbon dioxide from the by-product gas E, the concentration of carbon dioxide in the by-product gas E decreases. As a result, the calorific value per unit volume of the by-product gas E can be increased.

[0018] In addition, a heated gas discharge process is performed in which the by-product gas E from which carbon dioxide has been separated in the gas separation process is discharged from the introduction space 11 as heated gas B1, and a sweep gas supply process is performed in which sweep gas F11 is supplied to the sweep space 12.

[0019] By feeding the sweep gas F11 into the sweep space 12, the partial pressure of carbon dioxide in the sweep space 12 can be made lower than the partial pressure of carbon dioxide in the introduction space 11. Therefore, by continuously feeding the sweep gas F11 into the sweep space 12, it is possible to maintain a state in which the partial pressure of carbon dioxide in the sweep space 12 is lower than the partial pressure of carbon dioxide in the introduction space 11. This promotes permeation of carbon dioxide through the separation membrane 13. That is, separation of carbon dioxide from the by-product gas E and heat generation can be efficiently performed.

[0020] Then, an output gas delivery step is performed in which the sweep gas F11 and carbon dioxide are delivered as an output gas P11 from the sweep space 12. The delivered output gas P11 may be recovered and subjected to effective utilization (CCU) of the carbon dioxide contained therein.

[0021] In this embodiment, the heat-increasing gas B1 delivered in the heat-increasing gas delivery step may be recovered. The heat-increasing gas B1 is the by-product gas E from which carbon dioxide has been efficiently separated in the gas separation step and which has been heated, and therefore can be used as fuel in each factory in the steelworks.

[0022] The sweep gas F11 preferably contains hydrogen, and more preferably is hydrogen gas, because by containing hydrogen in the sweep gas F11 or by using hydrogen gas as the sweep gas F11, the recovered delivery gas P11 can be directly used for effective utilization (CCU) of the delivery gas P11 without the need for additional equipment for mixing carbon dioxide and hydrogen.

[0023] Furthermore, hydrogen has a larger diffusion coefficient in space than gases composed of other components. This promotes gas diffusion inside the sweep space 12 and suppresses uneven distribution of gas in the sweep space 12. This further promotes permeation of carbon dioxide through the separation membrane 13 and also promotes heat generation of the by-product gas. Furthermore, by increasing the partial pressure of hydrogen in the sweep space 12, the difference in partial pressure with respect to the partial pressure of hydrogen in the introduction space 11 can be reduced. This suppresses permeation of hydrogen through the separation membrane 13.

[0024] From the viewpoint of promoting the permeation of carbon dioxide through the separation membrane 13 and the heat increase of the by-product gas, the total pressure of the by-product gas E in the pipe 50a is preferably 20 kPa or more higher than the total pressure of the sweep gas F11 in the pipe 50c.

[0025] Furthermore, if the flow rate of the sweep gas F11 in the pipe 50c is excessively small compared to the flow rate of the by-product gas E in the pipe 50a, the partial pressure of carbon dioxide in the sweep space 12 cannot be maintained low, and the permeation of carbon dioxide from the introduction space 11 and the heat increase of the by-product gas cannot be promoted. For this reason, the flow rate of the sweep gas F11 in the pipe 50c is preferably set to a flow rate that is 0.01 times or more the flow rate of the by-product gas E in the pipe 50a.

[0026] On the other hand, if the flow rate of the sweep gas F11 in the pipe 50c exceeds a predetermined amount, the state of lowering the partial pressure of carbon dioxide will not change. Therefore, it is preferable that the flow rate of the sweep gas F11 in the pipe 50c is 10 times or less the flow rate of the by-product gas E in the pipe 50a.

[0027] In particular, when the sweep gas F11 contains hydrogen, the composition ratio of carbon dioxide and hydrogen in the delivery gas P11 can be freely adjusted by adjusting the flow rate of the sweep gas F11 in the pipe 50c within the range of 0.01 to 10 times the flow rate of the by-product gas E in the pipe 50a.

[0028] Furthermore, the carbon dioxide to hydrogen composition ratio required for the delivery gas P11 varies depending on the form of use (CCU) of the delivery gas P11. In the fuel gas heating device 1, the greater the flow rate of the sweep gas F11 in the pipe 50c relative to the flow rate of the by-product gas E in the pipe 50a, the more carbon dioxide can permeate the separation membrane 13, and the higher the carbon dioxide composition ratio in the delivery gas P11 can be. In other words, by adjusting the flow rate of the sweep gas F11 in the pipe 50c, it is possible to adjust the carbon dioxide to hydrogen composition ratio in the delivery gas P11. Therefore, adjusting the flow rate of the sweep gas F11 can significantly contribute to the effective utilization (CCU) of the recovered delivery gas P11.

[0029] The recovered delivery gas P11 is preferably used as a raw material gas for the hydrogenation reaction of carbon dioxide. Specifically, the hydrogenation reaction of carbon dioxide is more preferably a methanol synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 3.0 or a methane synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 4.0, compared to a carbon monoxide synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 1.0.

[0030] Second Embodiment A second embodiment of the present invention will be described below with reference to the drawings. Fig. 2 shows an example of the schematic configuration of a fuel gas heating device 2 in the second embodiment. Note that, with regard to each component of the second embodiment that is the same as that of the first embodiment, a description will be omitted. In the following description, "exhaust gas" refers to gas generated by burning heating gas in a combustion section provided in the fuel gas heating device.

[0031] 2, the fuel gas heating apparatus 2 of the second embodiment has a combustion unit 5. The combustion unit 5 corresponds to, for example, each plant in a steelworks that uses the by-product gas E, from which carbon dioxide has been separated and heated, as fuel.

[0032] 2, the combustion unit 5 combusts the heat-increasing gas B1 passed through the pipe 60b. The combustion unit 5 then sends the exhaust gas C2 generated by burning the heat-increasing gas B1 as a sweep gas F12 through the pipe 60c into the sweep space 22 of the separation mechanism 20. That is, the sweep gas F12 becomes the exhaust gas C2 generated by using the heat-increasing gas B1 in the combustion unit 5.

[0033] When the heat-reinforcing gas B1 is combusted in the combustion section 5 with air to utilize the energy, the combustible gas contained in the heat-reinforcing gas B1 reacts with oxygen. Specifically, hydrocarbons are converted into carbon dioxide and water vapor, carbon monoxide is converted into carbon dioxide, and hydrogen is converted into water vapor.

[0034] Furthermore, by feeding the exhaust gas C2 into the sweep space 22 as the sweep gas F12, the partial pressure of carbon dioxide in the sweep space 22 can be made lower than the partial pressure of carbon dioxide in the introduction space 21. Therefore, by continuously feeding the sweep gas F12 into the sweep space 22, it is possible to maintain a state in which the partial pressure of carbon dioxide in the sweep space 22 is lower than the partial pressure of carbon dioxide in the introduction space 21. This can promote permeation of carbon dioxide through the separation membrane 23. That is, separation of carbon dioxide from the by-product gas E and heat generation can be efficiently performed.

[0035] Furthermore, in this embodiment as well, by separating carbon dioxide from the by-product gas E in the introduction space 21 of the separation mechanism 20, the concentration of carbon dioxide in the by-product gas E decreases. Therefore, the heat quantity per unit volume of the by-product gas E can be increased. As a result, the heat quantity held by the heat-increasing gas B1 introduced from the introduction space 21 increases, which can greatly contribute to the utilization of the heat-increasing gas B1 in the combustion section 5.

[0036] Furthermore, the sweep gas F12 and carbon dioxide are delivered as a delivery gas P12 from the sweep space 22. The delivered delivery gas P12 may be recovered and used for the effective utilization (CCU) of the carbon dioxide contained therein.

[0037] Here, carbon dioxide is separated to increase the heat of by-product gas E, and the heated by-product gas E is used as fuel within the factory, which generates carbon dioxide again. In order to prevent this carbon dioxide from being released into the atmosphere, there has traditionally been a problem in that it is necessary to install separate carbon dioxide separation and capture equipment.

[0038] In contrast to this, in the present embodiment, the carbon dioxide that has permeated the separation membrane 23 and the carbon dioxide contained in the exhaust gas C2 can be recovered at the same time as the delivery gas P12. That is, the carbon dioxide contained in the by-product gas E and the carbon dioxide contained in the exhaust gas C2 generated after the heat-reinforcing gas B1 is used in the combustion section 5 can be recovered in a single facility (the fuel gas heat-reinforcing device 2). This contributes to saving space in the facility and improving the efficiency of carbon dioxide recovery.

[0039] Here, the by-product gas E contains hydrogen. Like carbon dioxide, the hydrogen contained in the by-product gas E easily permeates the separation membrane 23. Therefore, on the premise that the permeability coefficient of carbon dioxide is larger than the permeability coefficient of hydrogen, a separation membrane 23 that is selectively permeable to carbon dioxide is adopted.

[0040] However, when the partial pressure difference of hydrogen becomes larger than the partial pressure difference of carbon dioxide in the inlet space 21 and the sweep space 22 of the separation mechanism 20, the permeation flux of hydrogen through the separation membrane 23 becomes larger. In this case, hydrogen moves (permeates) from the inlet space 21 to the sweep space 22 through the separation membrane 23. As a result, the amount of combustible gas remaining in the by-product gas E decreases, and the amount of heat that can be retained in the heat-increasing gas B1 decreases. For this reason, it is necessary to make the partial pressure difference of hydrogen smaller than the partial pressure difference of carbon dioxide in the inlet space 21 and the sweep space 22.

[0041] When atmospheric pressure blast furnace gas (carbon dioxide concentration: 22%, hydrogen concentration: 4%) is used as the by-product gas E and atmospheric pressure air is used for combustion in the combustion section 5, the carbon dioxide concentration of the exhaust gas C2 used as the sweep gas F12 is approximately 20%. Based on this, when the partial pressure difference of hydrogen is to be made smaller than the partial pressure difference of carbon dioxide in the introduction space 21 and the sweep space 22, it is preferable to reduce the pressure of the sweep gas F12 fed into the sweep space 22 or increase the pressure of the by-product gas E introduced into the introduction space 21.

[0042] Specifically, when reducing the pressure of the sweep gas F12, it is preferable to set the total pressure of the sweep gas F12 in the pipe 60c to -10 kPaG. When increasing the pressure of the by-product gas E, it is preferable to set the total pressure of the by-product gas E in the pipe 60a to +15 kPaG. Therefore, it is preferable to set the pressure of the by-product gas E to be 15 kPa or more higher than the pressure of the sweep gas F12.

[0043] <Third embodiment> A third embodiment of the present invention will be described below with reference to the drawings. Fig. 3 shows an example of a schematic configuration of a fuel gas heating device 3 in the third embodiment. Note that, with regard to each component of the third embodiment, a description of the same components as those in the first or second embodiment will be omitted.

[0044] 3, the fuel gas heat pump 3 of the third embodiment includes a pipe 70e. The pipe 70e is connected to a pipe 70c that supplies the exhaust gas C3 as the sweep gas F13. The pipe 70e supplies the auxiliary gas G3. That is, in this embodiment, the auxiliary gas G3 can be added to the sweep gas F13 supplied to the swept space 32 and then supplied to the swept space 32.

[0045] If the flow rate of the sweep gas F13 (exhaust gas C3) in the pipe 70c is excessively small compared to the flow rate of the by-product gas E in the pipe 70a, the partial pressure of carbon dioxide in the sweep space 32 cannot be maintained low, and the permeation of carbon dioxide from the introduction space 31 and the increase in heat of the by-product gas cannot be promoted.

[0046] Therefore, in this embodiment, by adding the auxiliary gas G3 to the sweep gas F13 (exhaust gas C3) flowing through the pipe 70c, it is possible to adjust the flow rate of the sweep gas F13 (exhaust gas C3 and auxiliary gas G3) fed into the swept space 32. This adjustment is particularly effective when the flow rate of the sweep gas F13 (exhaust gas C3) flowing through the pipe 70c is 0.1 times or less the flow rate of the by-product gas E flowing through the pipe 70a.

[0047] On the other hand, if the flow rate of the sweep gas F13 (exhaust gas C3 and auxiliary gas G3) in the pipe 70c exceeds a predetermined amount, the state of lowering the partial pressure of carbon dioxide will not change. For this reason, it is preferable that the flow rate of the sweep gas F13 (exhaust gas C3 and auxiliary gas G3) in the pipe 70c be 10 times or less the flow rate of the by-product gas E in the pipe 70a.

[0048] The auxiliary gas G3 preferably contains hydrogen, and more preferably is hydrogen gas. By making the auxiliary gas G3 contain hydrogen or by using hydrogen gas as the auxiliary gas G3, the delivery gas P13 delivered from the sweep space 32 of the separation mechanism 30 becomes a gas containing carbon dioxide permeated through the separation membrane 33, carbon dioxide contained in the exhaust gas C3, and hydrogen contained in the auxiliary gas G3. Therefore, when effectively utilizing the recovered delivery gas P13 (CCU), the recovered delivery gas P13 can be directly used without the need to install additional equipment for mixing carbon dioxide and hydrogen.

[0049] Furthermore, hydrogen has a larger diffusion coefficient in space than gases composed of other components. This promotes gas diffusion within the sweep space 32 and suppresses uneven distribution of gas within the sweep space 32. This further promotes permeation of carbon dioxide through the separation membrane 33 and also promotes heat generation of the by-product gas. Furthermore, by increasing the partial pressure of hydrogen in the sweep space 32, the difference in partial pressure with respect to the partial pressure of hydrogen in the introduction space 31 can be reduced. This suppresses permeation of hydrogen through the separation membrane 33.

[0050] When the sweep gas F13 contains hydrogen, the composition ratio of carbon dioxide and hydrogen in the delivery gas P13 can be freely adjusted by adjusting the flow rate of the sweep gas F13 in the pipe 70c within the range of 0.01 to 10 times the flow rate of the by-product gas E in the pipe 70a.

[0051] Furthermore, the carbon dioxide to hydrogen composition ratio required for the delivery gas P13 varies depending on the form of use (CCU) of the delivery gas P13. In the fuel gas heating device 3, the greater the flow rate of the sweep gas F13 in the pipe 70c relative to the flow rate of the by-product gas E in the pipe 70a, the more carbon dioxide can permeate the separation membrane 33, and the higher the carbon dioxide composition ratio in the delivery gas P13 can be. In other words, by adjusting the flow rate of the sweep gas F13 in the pipe 70c, it is possible to adjust the carbon dioxide to hydrogen composition ratio in the delivery gas P13. Therefore, adjusting the flow rate of the sweep gas F13 can significantly contribute to the effective utilization (CCU) of the recovered delivery gas P13.

[0052] The recovered delivery gas P13 is preferably used as a raw material gas for the hydrogenation reaction of carbon dioxide. Specifically, the hydrogenation reaction of carbon dioxide is more preferably a methanol synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 3.0 or a methane synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 4.0, compared to a carbon monoxide synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 1.0.

[0053] <Fourth embodiment> A fourth embodiment of the present invention will now be described with reference to the drawings. Fig. 4 shows an example of a schematic configuration of a fuel gas heat increasing device 4 according to the fourth embodiment.

[0054] 4, the fuel gas heat pump 4 of the fourth embodiment includes a first separation mechanism 40, a second separation mechanism 90, a pipe 80, and a combustion section 7. The first separation mechanism 40 includes a first inlet space 41, a first sweep space 42, and a first separation membrane 43. The second separation mechanism 90 includes a second inlet space 91, a second sweep space 92, and a second separation membrane 93. The pipe 80 includes a pipe 80a for feeding the by-product gas E, a pipe 80b for feeding the first heat-increasing gas B14, a pipe 80c for feeding the first sweep gas F14, a pipe 80d for feeding the first delivery gas P14, a pipe 80f for feeding the second heat-increasing gas B2, a pipe 80g for feeding the second sweep gas F2, and a pipe 80h for feeding the second delivery gas P2. The combustion section 7 corresponds to, for example, each plant in a steelworks that uses the by-product gas E, from which carbon dioxide has been separated and heated, as fuel.

[0055] The first separation membrane 43 and the second separation membrane 93 have a property of higher permeation selectivity for carbon dioxide than for hydrogen and carbon monoxide. Various types of separation membranes, such as inorganic membranes and organic membranes, may be used as the first separation membrane 43 and the second separation membrane 93. When an inorganic membrane is used as the first separation membrane 43 and the second separation membrane 93, permeation selectivity can be exhibited due to its high affinity for carbon dioxide. For the inorganic membrane, DDR-type zeolite or CHA-type zeolite may be used. Furthermore, when an organic membrane is used as the first separation membrane 43 and the second separation membrane 93, permeation selectivity for carbon dioxide can be exhibited due to differences in solubility and diffusibility in polymers. For the organic membrane, a polyimide, a cellulose acetate polymer, or the like may be used.

[0056] In the fourth embodiment, a method for increasing the heat of fuel gas is performed by separating carbon dioxide from by-product gas E and increasing its heat using the configuration shown in Fig. 4. Specifically, first, a fuel gas introduction step is performed in which by-product gas E is introduced into a first introduction space 41 of a first separation mechanism 40 having a first introduction space 41 and a first sweep space 42 separated by a first separation membrane 43. The by-product gas E is sent through a by-product gas piping M and may be compressed by a compressor N before being introduced.

[0057] Next, a first gas separation step is performed in which carbon dioxide contained in the by-product gas E is passed through the first separation membrane 43 and transferred from the first introduction space 41 to the first sweep space 42. By separating carbon dioxide from the by-product gas E, the concentration of carbon dioxide in the by-product gas E decreases. This makes it possible to increase the calorific value per unit volume of the by-product gas E. As a result, the calorific value held by the first heat-increasing gas B14 discharged from the first introduction space 41 increases, which can greatly contribute to the utilization of the first heat-increasing gas B14 in the combustion section 7.

[0058] In addition, a first heat-increasing gas discharge process is performed in which the by-product gas E from which carbon dioxide has been separated in the first gas separation process is discharged from the first introduction space 41 as a first heat-increasing gas B14, a heat-increasing gas use process is performed in which the first heat-increasing gas B14 discharged in the first heat-increasing gas discharge process is used in the combustion section 7, and a first sweeping gas supply process is performed in which the exhaust gas C4 generated in the heat-increasing gas use process is supplied to the first sweeping space 42 as a first sweeping gas F14.

[0059] 4, the combustion unit 7 combusts the first heat-increasing gas B14 passed through the pipe 80b. The combustion unit 7 then combusts the first heat-increasing gas B14, generates exhaust gas C4, and passes the exhaust gas C4 through the pipe 80c to the first sweep space 42 of the first separation mechanism 40 as a first sweep gas F14. That is, the first sweep gas F14 becomes the exhaust gas C4 generated by using the first heat-increasing gas B14 in the combustion unit 7.

[0060] When the first heat-increasing gas B14 is combusted in the combustion section 7 with air to utilize the energy, the combustible gas contained in the first heat-increasing gas B14 reacts with oxygen. Specifically, hydrocarbons are converted into carbon dioxide and water vapor, carbon monoxide is converted into carbon dioxide, and hydrogen is converted into water vapor.

[0061] Furthermore, by feeding the exhaust gas C4 as the first sweep gas F14 into the first sweep space 42, the partial pressure of carbon dioxide in the first sweep space 42 can be made lower than the partial pressure of carbon dioxide in the first introduction space 41. Therefore, by continuously feeding the first sweep gas F14 into the first sweep space 42, it is possible to maintain a state in which the partial pressure of carbon dioxide in the first sweep space 42 is lower than the partial pressure of carbon dioxide in the first introduction space 41. This can promote permeation of carbon dioxide through the first separation membrane 43. That is, separation of carbon dioxide from the by-product gas E and heat increase can be efficiently performed.

[0062] Next, a first delivery gas delivery step is performed in which the first sweep gas F14 and carbon dioxide are delivered as a first delivery gas P14 from the first sweep space 42. Here, carbon dioxide is separated to increase the heat of the by-product gas E, and the heated by-product gas E is used as fuel in the factory, thereby generating carbon dioxide again. In order to prevent this carbon dioxide from being released into the atmosphere, there has traditionally been a problem in that it is necessary to install a separate carbon dioxide separation and capture facility.

[0063] In contrast to this, in the present embodiment, the carbon dioxide that has permeated the first separation membrane 43 and the carbon dioxide contained in the exhaust gas C4 can be combined at once as the first delivered gas P14. That is, the carbon dioxide contained in the by-product gas E and the carbon dioxide contained in the exhaust gas C4 that is generated after the first heat-increasing gas B14 is used in the combustion section 7 can be combined in a single facility (first separation mechanism 40). This contributes to space saving of the facility and to more efficient collection of carbon dioxide.

[0064] Next, a first delivery gas introduction step is performed in which the first delivery gas P14 is introduced into the second introduction space 91 of the second separation mechanism 90, which has a second introduction space 91 and a second sweep space 92 separated by a second separation membrane 93. Then, a second gas separation step is performed in which carbon dioxide contained in the first delivery gas P14 is permeated through the second separation membrane 93 and moved from the second introduction space 91 to the second sweep space 92.

[0065] By separating carbon dioxide from the first delivery gas P14, the concentration of carbon dioxide in the first delivery gas P14 is further reduced. Therefore, the calorific value per unit volume of the first delivery gas P14 can be further increased. As a result, the calorific value held by the second heat-increasing gas B2 introduced from the second introduction space 91 is also further increased.

[0066] Furthermore, a second heat-increasing gas discharge step is performed in which the first delivery gas P14 from which carbon dioxide has been separated in the second gas separation step is discharged as a second heat-increasing gas B2 from the second introduction space 91. In this embodiment, the second heat-increasing gas B2 discharged in the second heat-increasing gas discharge step may be recovered. The second heat-increasing gas B2 is the first delivery gas P14 (by-product gas E) from which carbon dioxide has been efficiently separated and heated in the second gas separation step, and therefore can be used as fuel in each factory in the steelworks.

[0067] Then, a second sweep gas supplying step is performed in which a second sweep gas F2 is supplied to the second sweep space 92. By supplying the second sweep gas F2 to the second sweep space 92, the partial pressure of carbon dioxide in the second sweep space 92 can be made lower than the partial pressure of carbon dioxide in the second introduction space 91. Therefore, by continuously supplying the second sweep gas F2 to the second sweep space 92, it is possible to maintain a state in which the partial pressure of carbon dioxide in the second sweep space 92 is lower than the partial pressure of carbon dioxide in the second introduction space 91. This can promote permeation of carbon dioxide through the second separation membrane 93. That is, separation of carbon dioxide from the by-product gas E and heat increase can be efficiently performed.

[0068] Then, a second delivery gas delivery step is performed in which the second sweep gas F2 and carbon dioxide are delivered as the second delivery gas P2 from the second sweep space 92. The delivered second delivery gas P2 has a higher carbon dioxide content than the first delivery gas P14 delivered by the first separation mechanism 40. Therefore, the second delivery gas P2 can be more effectively utilized for carbon dioxide effective utilization (CCU).

[0069] The second sweep gas F2 preferably contains hydrogen, and more preferably is hydrogen gas, because by containing hydrogen in the second sweep gas F2 or by using hydrogen gas as the second sweep gas F2, the recovered second delivery gas P2 can be directly utilized for effective utilization (CCU) of the recovered second delivery gas P2 without the need for additional equipment for mixing carbon dioxide and hydrogen.

[0070] Furthermore, hydrogen has a larger diffusion coefficient in space than gases composed of other components. This promotes gas diffusion inside the second sweep space 92 and suppresses uneven distribution of gas in the second sweep space 92. This further promotes permeation of carbon dioxide through the second separation membrane 93 and also promotes heat increase of the second heat-increasing gas B2. Furthermore, by increasing the partial pressure of hydrogen in the second sweep space 92, the difference in partial pressure with respect to the hydrogen partial pressure in the second introduction space 91 can be reduced. This suppresses permeation of hydrogen through the second separation membrane 93.

[0071] Here, the by-product gas E contains hydrogen. Like carbon dioxide, the hydrogen contained in the by-product gas E easily permeates the first separation membrane 43. Therefore, on the premise that the permeability coefficient of carbon dioxide is larger than the permeability coefficient of hydrogen, a first separation membrane 43 that is selectively permeable to carbon dioxide is adopted.

[0072] However, when the partial pressure difference of hydrogen becomes larger than the partial pressure difference of carbon dioxide in the first introduction space 41 and the first sweep space 42 of the first separation mechanism 40, the permeation flux of hydrogen through the first separation membrane 43 becomes larger. In this case, hydrogen moves (permeates) from the first introduction space 41 to the first sweep space 42 through the first separation membrane 43. As a result, the amount of combustible gas remaining in the by-product gas E decreases, and the amount of heat that can be retained in the first heat-increasing gas B14 decreases. For this reason, it is necessary to make the partial pressure difference of hydrogen smaller than the partial pressure difference of carbon dioxide in the first introduction space 41 and the first sweep space 42.

[0073] When atmospheric pressure blast furnace gas (carbon dioxide concentration: 22%, hydrogen concentration: 4%) is used as the by-product gas E and atmospheric pressure air is used for combustion in the combustion section 7, the carbon dioxide concentration of the exhaust gas C4 adopted as the first sweep gas F14 is approximately 20%. Based on this, when the partial pressure difference of hydrogen is made smaller than the partial pressure difference of carbon dioxide in the first introduction space 41 and the first sweep space 42, the first sweep gas F14 fed into the first sweep space 42 may be reduced in pressure, or the by-product gas E introduced into the first introduction space 41 may be increased in pressure.

[0074] Specifically, when the first sweep gas F14 is reduced in pressure, the total pressure of the first sweep gas F14 in the pipe 80c is preferably set to -10 kPaG. When the by-product gas E is increased in pressure, the total pressure of the by-product gas E in the pipe 80a is preferably set to +15 kPaG. Therefore, the pressure of the by-product gas E is preferably set to be 15 kPa or more higher than the pressure of the first sweep gas F14.

[0075] Furthermore, if the flow rate of the second sweep gas F2 in the pipe 80g is excessively small relative to the flow rate of the first delivery gas P14 in the pipe 80d, the partial pressure of carbon dioxide in the second sweep space 92 cannot be maintained low, and the permeation of carbon dioxide from the second introduction space 91 and the heat increase of the second heat increase gas B2 cannot be promoted. Therefore, it is preferable that the flow rate of the second sweep gas F2 in the pipe 80g is 0.01 times or more the flow rate of the first delivery gas P14 in the pipe 80d.

[0076] On the other hand, if the flow rate of the first delivery gas P14 in the pipe 80d exceeds a predetermined amount, the partial pressure of carbon dioxide is not reduced. Therefore, it is preferable that the flow rate of the second sweep gas F2 in the pipe 80g is 10 times or less the flow rate of the first delivery gas P14 in the pipe 80d.

[0077] In particular, when the second sweep gas F2 contains hydrogen, the composition ratio of carbon dioxide and hydrogen in the second delivery gas P2 can be freely adjusted by adjusting the flow rate of the second sweep gas F2 in the pipe 80g within a range of 0.01 to 10 times the flow rate of the first delivery gas P14 in the pipe 80d.

[0078] Furthermore, the carbon dioxide to hydrogen composition ratio required for the second delivery gas P2 varies depending on the form of use (CCU) of the second delivery gas P2. In the fuel gas heat pump 4, the larger the flow rate of the second sweep gas F2 in the pipe 80g relative to the flow rate of the first delivery gas P14 in the pipe 80d, the more carbon dioxide can permeate the second separation membrane 93, and the higher the carbon dioxide composition ratio in the second delivery gas P2 can be. That is, by adjusting the flow rate of the second sweep gas F2 in the pipe 80g, it is possible to adjust the carbon dioxide to hydrogen composition ratio in the second delivery gas P2. Therefore, adjusting the flow rate of the second sweep gas F2 can significantly contribute to the effective utilization (CCU) of the recovered second delivery gas P2.

[0079] The recovered second delivery gas P2 is preferably used as a raw material gas for the hydrogenation reaction of carbon dioxide. Specifically, the hydrogenation reaction of carbon dioxide is more preferably a methanol synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 3.0 or a methane synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 4.0, compared to a carbon monoxide synthesis reaction in which the stoichiometric ratio of hydrogen / carbon dioxide is 1.0.

[0080] Here, if the flow rate of the first sweep gas F14 in the pipe 80c is excessively small compared to the flow rate of the by-product gas E in the pipe 80a, the partial pressure of carbon dioxide in the first sweep space 42 cannot be maintained low, and the permeation of carbon dioxide from the first introduction space 41 and the increase in heat of the by-product gas E cannot be promoted.

[0081] Therefore, in this embodiment as well, similarly to the fuel gas heat booster 3 of the third embodiment (see FIG. 3), it is preferable to provide a pipe for feeding the auxiliary gas, which is connected to the pipe 80c for feeding the exhaust gas C4.

[0082] Adding an auxiliary gas to the first sweep gas F14 (exhaust gas C4) passing through the pipe 80c makes it possible to adjust the flow rate of the first sweep gas F14 sent into the first sweep space 42. This adjustment is particularly effective when the flow rate of the first sweep gas F14 (exhaust gas C4) passing through the pipe 80c is 0.1 times or less the flow rate of the by-product gas E passing through the pipe 80a.

[0083] On the other hand, if the flow rate of the first sweep gas F14 in the pipe 80c exceeds a predetermined amount, the state of lowering the partial pressure of carbon dioxide will not change. For this reason, it is preferable that the flow rate of the first sweep gas F14 (exhaust gas C4 and auxiliary gas) in the pipe 80c is 10 times or less the flow rate of the by-product gas E in the pipe 80a.

[0084] The auxiliary gas preferably contains hydrogen, and is more preferably hydrogen gas. Hydrogen has a larger diffusion coefficient in space than gases composed of other components. This promotes gas diffusion inside the first sweep space 42 and suppresses uneven distribution of gas in the first sweep space 42. This further promotes permeation of carbon dioxide through the first separation membrane 43 and also promotes heat increase of the by-product gas. Furthermore, by increasing the partial pressure of hydrogen in the first sweep space 42, the partial pressure difference with the partial pressure of hydrogen in the first introduction space 41 can be reduced. This suppresses permeation of hydrogen through the first separation membrane 43. [Example]

[0085] Next, an example will be described in which the method for increasing the heat of fuel gas and the method for producing raw material according to the present invention were used to separate and increase the heat of carbon dioxide in fuel gas, and to carry out a hydrogenation reaction of carbon dioxide.

[0086] In the examples, a by-product gas was used as an example of the fuel gas. Specifically, a blast furnace gas containing 50% by volume of nitrogen, 24% by volume of carbon monoxide, 22% by volume of carbon dioxide, and 4% by volume of hydrogen was used as the by-product gas. 3 / h was used.

[0087] The fuel gas heat pump 2 of the second embodiment was used as Example 1, and the fuel gas heat pump 4 of the fourth embodiment was used as Example 2. In Comparative Example 1, no separation mechanism was used, and by-product gas was used in the combustion section. The results of the examples are shown in Tables 1 and 2. Table 1 shows the composition (vol %) of each gas generated in each example. Table 2 shows the flow rate (Nm m ) of each gas generated in each example. 3 / h), heat amount (MJ / Nm 3 ) and pressure (kPaG). In Examples 1 and 2 of the present invention, a CHA zeolite membrane was used as the separation membrane in the separation mechanism. The CHA zeolite membrane was used after a simulation of its carbon dioxide separation performance (permeation selectivity) was carried out in advance.

[0088] [Table 1]

[0089] [Table 2]

[0090] In Example 1, as shown in Table 1, by using the (first) separation mechanism, a (first) heat-increasing gas with a carbon dioxide concentration of 3% by volume could be obtained from a by-product gas with a carbon dioxide concentration of 22% by volume. In this case, as shown in Table 2, the calorific value was 3.46 MJ / Nm 3 The calorific value of the by-product gas was 4.02MJ / Nm 3 Furthermore, in the combustion section, the flow rate of the combustion air, which is 79% by volume of nitrogen and 21% by volume of oxygen, is 0.60 Nm 3 The first heat-generating gas was burned (used) at an air ratio of 1.1 while using the fuel at a rate of 1.20 Nm3 / h. As a result, the exhaust gas, which was composed of 79% by volume of nitrogen, 1% by volume of oxygen, and 20% by volume of carbon dioxide, was burned at a rate of 1.20 Nm3 / h. 3The resulting exhaust gas was used as a (first) sweep gas, and the (first) delivery gas was 1.48 Nm3 containing 66% by volume of nitrogen, 1% by volume of carbon monoxide, 30% by volume of carbon dioxide, and 3% by volume of hydrogen. 3 / h was obtained. That is, in the (first) sweep space portion of the (first) separation mechanism, the carbon dioxide that permeated the separation membrane was efficiently recovered. In this example, the specific heat of the (first) heat-increasing gas in the combustion portion was 1.31 kJ / (Nm 3 ·K), and the adiabatic flame temperature was 583°C.

[0091] In Example 2, the (first) delivery gas obtained in Example 1 was introduced into the (second) introduction space of the (second) separation mechanism, and a (second) sweep gas containing 100% by volume of hydrogen was introduced into the (second) sweep space at a flow rate of 1.10 Nm 3 As a result, as shown in Table 1, the (first) delivery gas with a carbon dioxide concentration of 30% by volume was used to obtain the (second) heated gas with a carbon dioxide concentration of 11% by volume by using the (second) separation mechanism. At that time, as shown in Table 2, the calorific value was 0.32 MJ / Nm 3 The calorific value of the (first) gas sent out was 1.19MJ / Nm 3 Furthermore, the composition of the (second) discharge gas sent out from the (second) sweep space of the (second) separation mechanism was 3 vol% nitrogen, 23 vol% carbon dioxide, and 74 vol% hydrogen, as shown in Table 1. In other words, it was confirmed that the (second) discharge gas is useful as a raw material gas for a hydrogenation reaction (methanol synthesis reaction) in which the stoichiometric ratio of hydrogen to carbon dioxide is approximately 3.0.

[0092] In Comparative Example 1, the by-product gas was combusted (utilized) in the combustion section with an air ratio of 1.1. As a result, an exhaust gas containing 68% by volume of nitrogen, 1% by volume of oxygen, and 31% by volume of carbon dioxide was generated at a rate of 1.47 Nm3. 3 At this time, the specific heat of the by-product gas was 1.37 kJ / (Nm 3 ·K), and the adiabatic flame temperature was 525°C. [Explanation of symbols]

[0093] 1, 2, 3, 4 Fuel gas heating device 10, 20, 30 separation mechanism 11, 21, 31 Introduction space 12, 22, 32 Sweep space section 13, 23, 33 Separation membrane 40 First separation mechanism 41 First introduction space 42 1st sweep space section 43 First separation membrane 90 Second separation mechanism 91 Second introduction space 92 2nd sweep space section 93 Second separation membrane 50, 60, 70, 80 piping 5, 6, 7 Combustion section M By-product gas piping N Compressor

Claims

1. A method for increasing the heat of fuel gas by separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide, comprising: a fuel gas introducing step of introducing the fuel gas into an introduction space of a separation mechanism having an introduction space and a sweep space separated by a separation membrane; a gas separation step of causing carbon dioxide contained in the fuel gas to permeate through the separation membrane and move from the introduction space to the sweep space; a heated gas discharge step of discharging the fuel gas from which carbon dioxide has been separated in the gas separation step as a heated gas from the inlet space; a sweep gas supply step of supplying a sweep gas into the sweep space; a delivery gas delivery step of delivering the sweep gas and carbon dioxide from the sweep space as delivery gases; A method for increasing the heat of fuel gas, comprising:

2. The method of claim 1 , wherein the sweep gas contains hydrogen.

3. 3. The method for increasing the heat of fuel gas according to claim 1, wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

4. 3. A method for producing a raw material, comprising using the gas delivered by the method for increasing the temperature of a fuel gas according to claim 1 or 2 as a raw material gas for a carbon dioxide hydrogenation reaction.

5. 5. The method for producing a raw material according to claim 4, wherein the hydrogenation reaction is a methanol synthesis reaction.

6. The method for producing raw materials according to claim 4, wherein the hydrogenation reaction is a methane synthesis reaction.

7. 2. The method for increasing the heat of fuel gas according to claim 1, wherein the sweep gas is exhaust gas produced by using the heat-increasing gas in a combustion section.

8. 8. The method for increasing the heat of fuel gas according to claim 7, wherein the pressure of the fuel gas is greater than the pressure of the sweep gas by 15 kPa or more.

9. 9. The method for increasing the heat of fuel gas according to claim 7, wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

10. 9. The method for increasing the heat of fuel gas according to claim 7, wherein an auxiliary gas is added to the sweep gas and fed in the sweep gas feeding step.

11. The method for increasing the heat of fuel gas according to claim 10 , wherein the auxiliary gas contains hydrogen.

12. The method for increasing the heat of fuel gas according to claim 10, wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

13. A method for producing a raw material, comprising using the gas delivered by the method for increasing the temperature of a fuel gas according to claim 10 as a raw material gas for a carbon dioxide hydrogenation reaction.

14. 14. The method for producing a raw material according to claim 13, wherein the hydrogenation reaction is a methanol synthesis reaction.

15. 14. The method for producing a raw material according to claim 13, wherein the hydrogenation reaction is a methane synthesis reaction.

16. A method for producing a raw material, comprising using the gas delivered by the method for increasing the temperature of a fuel gas according to claim 11 as a raw material gas for a carbon dioxide hydrogenation reaction.

17. 17. The method for producing a raw material according to claim 16, wherein the hydrogenation reaction is a methanol synthesis reaction.

18. 17. The method for producing a feedstock according to claim 16, wherein the hydrogenation reaction is a methane synthesis reaction.

19. A method for increasing the heat of fuel gas by separating carbon dioxide from a fuel gas containing a combustible gas and carbon dioxide, comprising: a fuel gas introducing step of introducing the fuel gas into a first introduction space of a first separation mechanism having a first introduction space and a first sweep space separated by a first separation membrane; a first gas separation step of permeating carbon dioxide contained in the fuel gas through the first separation membrane and transferring it from the first inlet space to the first sweep space; a first heat-increasing gas discharge step of discharging the fuel gas from which carbon dioxide has been separated in the first gas separation step as a first heat-increasing gas from the first inlet space; a heat-increasing gas using step of using the first heat-increasing gas delivered in the first heat-increasing gas delivering step in a combustion section; a first sweep gas supplying step of supplying the exhaust gas generated in the heat-increasing gas using step as a first sweep gas into the first sweep space; a first delivery gas delivery step of delivering the first sweep gas and carbon dioxide from the first sweep space as a first delivery gas; a first delivery gas introducing step of introducing the first delivery gas into a second introduction space of a second separation mechanism having a second introduction space and a second sweep space separated by a second separation membrane; a second gas separation step of permeating carbon dioxide contained in the first delivery gas through the second separation membrane and transferring it from the second introduction space to the second sweep space; a second heated gas discharging step of discharging the first delivery gas from which carbon dioxide has been separated in the second gas separation step as a second heated gas from the second introduction space; a second sweep gas supply step of supplying a second sweep gas into the second sweep space; a second delivery gas delivery step of delivering the second sweep gas and carbon dioxide from the second sweep space as a second delivery gas; A method for increasing the heat of fuel gas, comprising:

20. 20. The method of claim 19, wherein the second sweep gas contains hydrogen.

21. 21. The method for increasing the heat of fuel gas according to claim 19 or 20, wherein the fuel gas is a by-product gas generated from a blast furnace or a converter.

22. 21. A method for producing a raw material, comprising using the second delivered gas delivered by the method for increasing the temperature of a fuel gas according to claim 19 or 20 as a raw material gas for a carbon dioxide hydrogenation reaction.

23. 23. The method for producing a feedstock according to claim 22, wherein the hydrogenation reaction is a methanol synthesis reaction.

24. 23. The method for producing a feedstock according to claim 22, wherein the hydrogenation reaction is a methane synthesis reaction.

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