Condensing device

Abstract

The present invention provides a condensing device capable of saving energy in a process for condensing gas, especially in a process for condensing fuel gas into liquid fuel. A condensing device according to an embodiment of the present invention is provided with a gas separator to which a mixed gas is supplied and which is capable of separating the mixed gas into a first gas and a second gas; a decompression device capable of decompressing the second gas; and a cooling device capable of cooling the second gas, wherein through the gas separator, the Joule-Thomson coefficient of the second gas is configured to be larger than the Joule-Thomson coefficient of the mixed gas.

Description

Condensing device

[0001] The present invention relates to a condensation device.

[0002] In recent years, with the aim of realizing a carbon-neutral society, it has been proposed to treat carbon oxides such as carbon monoxide and carbon dioxide as carbon resources and convert them into liquid fuels useful as basic industrial raw materials. For example, Patent Document 1 discloses a method for producing methanol in which a raw synthesis gas is introduced into a methanol synthesis reactor and a portion of the raw synthesis gas is converted into methanol. In the methanol production method described in Patent Document 1, a gas containing methanol is cooled, the methanol is condensed, and the liquid crude methanol and unreacted gas are separated. However, in such reaction systems that synthesize liquid fuels from carbon oxides, a very large amount of energy (heat removal energy) is required to condense the gaseous fuel components into a liquid state, and various issues remain to be addressed before this method can be put into practical use.

[0003] Japanese Patent Application Laid-Open No. 2020-63193

[0004] A primary object of the present invention is to provide a condensation device that can achieve energy savings in the process of condensing gas, particularly in the process of condensing fuel gas into liquid fuel.

[0005] [1] A condensation device according to an embodiment of the present invention includes a gas separator, a pressure reduction device, and a cooling device. The gas separator is supplied with a mixed gas containing a fuel gas. The gas separator is capable of separating the mixed gas into a first gas and a second gas containing a fuel gas. The pressure reduction device is capable of reducing the pressure of the second gas. The cooling device is capable of cooling the second gas. The condensation device is configured so that the Joule-Thomson coefficient of the second gas is greater than the Joule-Thomson coefficient of the mixed gas by passing through the gas separator. [2] The condensation device described in [1] above may further include at least one reactor. The at least one reactor is disposed upstream of the gas separator in the supply direction of the mixed gas to the gas separator. A raw material gas containing carbon oxides and hydrogen is supplied to the reactor. The reactor is capable of discharging a mixed gas containing fuel gas as a reaction product of the carbon oxides and hydrogen and the raw material gas remaining unreacted. [3] In the condensation device described in [2] above, the gas separator may be capable of separating the mixed gas supplied from the reactor into a first gas containing hydrogen as a main component and a second gas containing the fuel gas. [4] The condensation device described in [2] or [3] above may further include a return line. The return line may return to the reactor a gas component of the second gas that remains in a gaseous state even after decompression and cooling. [5] The condensation device described in [3] above may further include a gas-liquid separator. The gas-liquid separator is disposed downstream of the gas separator in the discharge direction of the second gas from the gas separator. The gas-liquid separator is capable of separating a liquid fuel condensed by decompression and cooling from a gas component of the second gas that remains in a gaseous state even after decompression and cooling. [6] In the condensation device described in any of [2] to [5] above, the reactor may be a membrane reactor. [7] In the condensation device according to any one of [1] to [6] above, the Joule-Thomson coefficient of the second gas may be 15.9 K / MPa or less. [8] In the condensation device according to any one of [1] to [7] above, the liquid fuel may contain alcohols as a main component.[9] The condensation device according to any one of [1] to [8] above may be a condensation device for fuel gas.

[0006] According to the embodiment of the present invention, energy can be saved in the process of condensing gas, particularly in the process of condensing fuel gas into liquid fuel.

[0007] Fig. 1 is a schematic configuration diagram of a fuel gas condensation apparatus according to one embodiment of the present invention. Fig. 2 is a schematic configuration diagram of a fuel gas condensation apparatus according to another embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a reactor provided in the fuel gas condensation apparatus of Fig. 1. Fig. 4 is a schematic cross-sectional view of another embodiment of the reactor provided in the fuel gas condensation apparatus of Fig. 1. Fig. 5 is a schematic cross-sectional view of yet another embodiment of the reactor provided in the fuel gas condensation apparatus of Fig. 1. Fig. 6 is a schematic perspective view of a separation membrane composite provided in the reactor of Fig. 5.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiment, but these are merely examples and do not limit the interpretation of the present invention.

[0009] A. Overview of Fuel Gas Condensation Apparatus FIG. 1 is a schematic diagram of a fuel gas condensation apparatus according to one embodiment of the present invention; FIG. 2 is a schematic diagram of a fuel gas condensation apparatus according to another embodiment of the present invention. In one embodiment, the condensation apparatus is a fuel gas condensation apparatus 100. The illustrated fuel gas condensation apparatus 100 is typically capable of condensing fuel gas to produce liquid fuel. That is, the fuel gas condensation apparatus 100 is capable of implementing a method for producing liquid fuel. As shown in FIG. 1, the fuel gas condensation apparatus 100 includes a gas separator 2, a pressure reducing device 53, and a cooling device 31. A mixed gas containing fuel gas is supplied to the gas separator 2. The gas separator 2 is capable of separating the mixed gas into a first gas and a second gas containing fuel gas. The second gas is typically discharged from the gas separator 2 after being separated in the gas separator 2. In the illustrated example, the pressure reducing device 53 and the cooling device 31 are each disposed downstream of the gas separator 2 in the discharge direction of the second gas from the gas separator 2. The pressure reducing device 53 is capable of reducing the pressure of the second gas. The cooling device 31 is capable of cooling the second gas. The fuel gas condensation device 100 is configured so that the Joule-Thomson coefficient of the second gas is greater than that of the mixed gas by passing the second gas through the gas separator 2. The inventors discovered that when cooling and condensing fuel gas or the like, gas components (particularly hydrogen) that are different from the fuel gas and present in the mixed gas cause significant energy consumption. Therefore, as a result of extensive research into liquid fuel separation and recovery means, they discovered that gas components contained in the second gas, particularly fuel gas, can be condensed with reduced energy by separating a mixed gas containing fuel gas into a first gas and a second gas containing fuel gas, increasing the Joule-Thomson coefficient of the second gas to a value greater than that of the mixed gas, and then reducing the pressure and cooling the second gas. Specifically, the gas separator 2 can separate the mixed gas into a first gas and a second gas containing fuel gas. The Joule-Thomson coefficient (hereinafter referred to as the JT coefficient) of the second gas after separation is larger than the JT coefficient of the mixed gas before separation. This means that the temperature of the second gas decreases more when the pressure of the second gas is reduced than that of the mixed gas.In other words, the gas separator 2 can perform a gas separation process in which the mixed gas is separated into a first gas and a second gas so that the JT coefficients satisfy the above-mentioned relationship. Therefore, when the second gas whose JT coefficient has been adjusted in this manner is depressurized by the depressurizing device 53 (depressurization process) and cooled by the cooling device 31 (cooling process), the temperature of the second gas can be efficiently lowered, even if the gas has the same heat capacity. This can reduce the heat removal energy required for condensing the gas components contained in the second gas, particularly the fuel gas. Therefore, the fuel gas can be condensed into a liquid fuel with reduced energy. In this specification, the term "liquid fuel" refers to a fuel that is in a liquid state at room temperature and normal pressure, or a fuel that can be liquefied under pressure at room temperature. Examples of fuels that are in a liquid state at room temperature and normal pressure include alcohols such as methanol and ethanol; C. ｎ H ２（ｍ－２ｎ） (m is an integer less than 90, and n is an integer less than 30); and mixtures thereof. Examples of fuels that can be liquefied under normal temperature and pressure include propane, butane, and mixtures thereof.

[0010] In one embodiment, the liquid fuel contains alcohols as a main component. If the main component of the liquid fuel is hydrocarbons, the components (typically, hydrogen separation membranes) of the gas separator may become clogged, which may reduce the function of the gas separator. In contrast, if the main component of the liquid fuel is alcohols, the function of the gas separator can be sufficiently maintained. Note that the main component means the component that is most abundant in terms of composition ratio.

[0011] In the above embodiment, the condenser condenses the fuel gas, but the present invention is not limited thereto. For example, the condenser may condense gas components contained in the second gas other than the fuel gas (hereinafter referred to as "other gas components"). Examples of other gas components include impurity gases, such as by-product gases produced in the reactor described below. When the condenser condenses the impurity gases, the impurities can be removed from the fuel gas in an energy-saving manner.

[0012] In one embodiment, the fuel gas condensation apparatus 100 further includes at least one reactor 1. The at least one reactor 1 is arranged upstream of the gas separator 2 in the supply direction of the mixed gas to the gas separator 2. A raw material gas containing carbon oxides and hydrogen is supplied to the reactor 1. The reactor 1 is capable of discharging the mixed gas. The mixed gas contains fuel gas as a reaction product of the carbon oxides and hydrogen, and raw material gas that remains unreacted. The reactor 1 is located on the opposite side of the gas separator 2 from the pressure reducing device 53. The liquid fuel condensation apparatus 100 may further include a supply unit 4 that supplies a raw material gas to the reactor 1. The supply unit 4 typically includes a supply line 41 through which the raw material gas passes.

[0013] As described above, the raw material gas contains carbon oxide and hydrogen. Examples of carbon oxide include carbon dioxide (CO ２ The raw material gas may contain a single carbon oxide or two or more kinds of carbon oxides. Among the carbon oxides, carbon dioxide (CO ２ ), and more preferably carbon dioxide (CO ) captured from the atmosphere by direct air capture technology (DAC). ２ The carbon oxide and hydrogen content ratios in the feed gas can be appropriately adjusted depending on the conversion reaction to be carried out in the reactor 1.

[0014] In the reactor 1, a conversion reaction (reaction step) between carbon oxides and hydrogen can be carried out. Examples of the conversion reaction between carbon oxides and hydrogen include a methanol synthesis reaction and an ethanol synthesis reaction, and preferably a methanol synthesis reaction. The methanol synthesis reaction can include the reactions of the following formulas (1) to (3): CO + 2H ２ ⇔CH ３ OH (1) CO ２ +3H ２ ⇔CH ３ OH+H ２ O (2) CO ２ +H ２ ⇔CO + H ２ O (3)

[0015] The reactions of the above formulas (1) to (3) are all equilibrium reactions. Therefore, carbon oxide and hydrogen are preferably reacted under high temperature and pressure. This can improve the conversion rate and reaction rate. The following explanation will be given using the synthesis of methanol as an example.

[0016] The pressure in the reactor 1 is, for example, 1.2 MPa (absolute pressure) or more, preferably 3.0 MPa (absolute pressure) or more, more preferably 3.5 MPa (absolute pressure) or more, and even more preferably 4.0 MPa (absolute pressure) or more. On the other hand, the pressure in the reactor 1 is, for example, 7.0 MPa (absolute pressure) or less, preferably 5.5 MPa (absolute pressure) or less. When the pressure in the reactor 1 is within the above range, the pressure of the mixed gas discharged from the reactor can also be adjusted to be within the above range. When the pressure of the mixed gas is within the above range, the pressure of the mixed gas can be used in the gas separator to efficiently separate a first gas containing hydrogen as a main component from a second gas containing fuel gas.

[0017] The temperature inside the reactor 1 is, for example, 200°C or higher, preferably 210°C or higher, and more preferably 220°C or higher. On the other hand, the temperature inside the reactor 1 is, for example, 320°C or lower, preferably 300°C or lower, and more preferably 290°C or lower. When the temperature inside the reactor 1 is within the above range, the temperature of the mixed gas discharged from the reactor can also be adjusted to be within the above range. When the temperature of the mixed gas is within the above range, liquefaction of the fuel gas in the gas separator can be suppressed.

[0018] As described above, the mixed gas discharged from the reactor 1 contains a fuel gas (typically, gaseous methanol) as a reaction product and a raw material gas (typically, hydrogen, or hydrogen and carbon oxides) that remains unreacted. The mixed gas may further contain a by-product gas produced in the above-described conversion reaction. The content of the fuel gas in the mixed gas is, for example, 1.0 mol% or more, preferably 3.0 mol% or more. On the other hand, the content of the fuel gas in the mixed gas is, for example, 60.0 mol% or less, or, for example, 55.0 mol% or less. The content ratios of various gases can be measured by gas chromatography or the like. The content ratio of the raw material gas in the mixed gas is, for example, 2.0 mol% or more, preferably 3.0 mol% or more. On the other hand, the upper limit of the content ratio of the raw material gas in the mixed gas is typically 90 mol%.

[0019] The reactor 1 and the gas separator 2 may be directly connected, or a pressure booster and / or a pressure reducer may be provided between the reactor 1 and the gas separator 2. The pressure booster can boost the pressure of the mixed gas sent from the reactor 1 to the gas separator 2. Specific examples of the pressure booster include a compressor and a blower. The pressure reducer can reduce the pressure of the mixed gas sent from the reactor 1 to the gas separator 2. Specific examples of the pressure reducer include a pressure reducing valve.

[0020] Furthermore, a removal device capable of removing some of the gas components contained in the mixed gas may be provided between the reactor 1 and the gas separator 2. With this configuration, even if the mixed gas discharged from the reactor contains gas components that reduce the performance of the gas separator, the removal device can remove the gas components. Therefore, it is possible to suppress a reduction in the performance of the gas separator and ensure the performance of the gas separator over a long period of time.

[0021] In one embodiment, the gas separator 2 is installed directly below the reactor 1, and the reactor 1 and the gas separator 2 are directly connected. With this configuration, the loss of pressure energy of the mixed gas can be reduced compared to when a pressure reducing device and / or a removal device is installed between the reactor and the gas separator. In addition, since a mixed gas with sufficient pressure can be supplied to the gas separator without a pressure booster, the power required to drive the pressure booster can be reduced.

[0022] In the illustrated example, the fuel gas condensation device 100 further includes a first connection line 51 that can supply the mixed gas discharged from the reactor 1 to the gas separator 2. The first connection line 51 directly connects the reactor 1 and the gas separator 2.

[0023] After being supplied to the gas separator 2, the mixed gas is separated in the gas separator 2 into a first gas containing hydrogen as a main component and a second gas containing fuel gas. In other words, the gas separator 2 separates the mixed gas supplied from the reactor 1 into a first gas containing hydrogen as a main component and a second gas containing fuel gas (gas separation process). This reduces the amount of hydrogen contained in the second gas, thereby enabling the JT coefficient of the separated second gas to be sufficiently increased. This means that the temperature of the second gas decreases significantly during decompression, and the fuel gas contained in the second gas can be condensed with greater energy savings, even when using gases with the same heat capacity.

[0024] In the illustrated example, the condensation device 100 includes one gas separator, but the number of gas separators is not limited to this. The condensation device 100 may include multiple gas separators. By appropriately changing the number of gas separators, it is possible to control the compositions of the first gas and the second gas.

[0025] The pressure of the mixed gas immediately before being supplied to the gas separator 2 is, for example, 1.2 MPa (absolute pressure) to 7.0 MPa (absolute pressure), and preferably 3.0 MPa (absolute pressure) to 5.5 MPa (absolute pressure). The temperature of the mixed gas immediately before being supplied to the gas separator 2 is, for example, 200°C to 320°C, and preferably 210°C to 300°C. The JT coefficient of the mixed gas immediately before being supplied to the gas separator 2 is, for example, 0.7 K / MPa to 10.4 K / MPa. The JT coefficient of the mixed gas can be calculated by multiplying the sum of (the JT coefficient at the partial pressure of each gas component contained in the source gas) by (the composition ratio of the corresponding gas components).

[0026] The first gas separated in the gas separator 2 can be used for any appropriate purpose. The first gas may be used as fuel for peripheral equipment or as a raw material for other conversion reactions. The second gas separated in the gas separator 2 is sent from the gas separator 2 to a pressure reducing device 53 or a cooling device 31, which will be described in detail later.

[0027] The gas separator 2 may have any appropriate configuration. In one embodiment, the gas separator 2 is provided with a hydrogen separation membrane that is permeable to hydrogen. With such a configuration, the pressure of the mixed gas can be suitably utilized to smoothly separate the mixed gas into the first gas and the second gas. An example of such a gas separator 2 is the DDR-type zeolite membrane described in Japanese Patent Laid-Open Publication No. 2004-105942. The entire disclosure of this publication is incorporated herein by reference.

[0028] The hydrogen content in the first gas is, for example, 50 mol% or more, preferably 70 mol% or more. Meanwhile, the hydrogen content in the first gas is, for example, 100 mol% or less, or, for example, 90 mol% or less. The amount of hydrogen contained in the first gas is, for example, 0.80 or more, preferably 0.90 or more, when the amount of hydrogen contained in the mixed gas discharged from the reactor 1 is taken as 1 on a molar basis. When the first gas contains such an amount of hydrogen, the amount of hydrogen remaining in the second gas can be sufficiently reduced, and the energy required for cooling the second gas (heat removal energy) during condensation of the fuel gas can be sufficiently reduced. Meanwhile, the amount of hydrogen contained in the first gas is, for example, 1.0 or less, when the amount of hydrogen contained in the mixed gas discharged from the reactor 1 is taken as 1 on a molar basis. When the first gas contains such an amount of hydrogen, liquefaction of the fuel gas in the gas separator can be stably suppressed, resulting in improved liquid fuel production efficiency.

[0029] The first gas may contain carbon oxide in addition to hydrogen. The carbon oxide content in the first gas is, for example, 0 mol % or more, preferably 10 mol % or more. On the other hand, the carbon oxide content in the first gas is, for example, less than 50 mol %, or, for example, 30 mol % or less. The amount of carbon oxide contained in the first gas is, when the amount of carbon oxide contained in the mixed gas is taken as 1 on a molar basis, for example, 0.60 or more, preferably 0.70 or more. On the other hand, the amount of carbon oxide contained in the first gas is, when the amount of carbon oxide contained in the mixed gas is taken as 1 on a molar basis, for example, 0.80 or less.

[0030] The first gas is substantially free of fuel gas, and the content of fuel gas in the first gas is, for example, 1.0 mol % or less, preferably 0.5 mol % or less, more preferably 0.1 mol % or less, and even more preferably 0 mol %.

[0031] The second gas separated in the gas separator 2 contains at least a fuel gas (typically, gaseous methanol). The content of the fuel gas in the second gas is, for example, 9.0 mol% or more, preferably 15.0 mol% or more. On the other hand, the content of the fuel gas in the second gas is, for example, 95.0 mol% or less, or, for example, 85.0 mol% or less. If the content of the fuel gas in the second gas is equal to or greater than the above lower limit, the liquid fuel can be efficiently recovered in the gas-liquid separator.

[0032] The second gas may contain, in addition to the fuel gas, a raw material gas (typically, carbon oxide, or hydrogen and carbon oxide) and / or an impurity gas such as a by-product gas.

[0033] The pressure of the second gas is typically lower than the pressure of the mixed gas discharged from the reactor 1. The gas separator 2 may separate the second gas at atmospheric pressure (0.1 MPa) or at a pressurized state (exceeding 0.1 MPa). When the gas separator 2 is equipped with a hydrogen separation membrane, the gas separator 2 can stably separate the second gas at a pressurized state. In this case, the pressurized second gas is discharged from the gas separator 2. The pressure of the pressurized second gas is preferably 3.0 MPa (absolute pressure) or more, more preferably 3.3 MPa (absolute pressure) or more. On the other hand, the pressure of the pressurized second gas is, for example, 6.8 MPa (absolute pressure) or less, preferably 5.3 MPa (absolute pressure) or less, more preferably 5.0 MPa (absolute pressure) or less. The temperature of the second gas is, for example, 200°C or more, preferably 210°C or more, more preferably 220°C or more. On the other hand, the upper limit of the temperature of the second gas is typically 300°C.

[0034] The JT coefficient of the second gas exceeds, for example, 0.7 K / MPa. On the other hand, the upper limit of the JT coefficient of the second gas is typically 15.9 K / MPa. In other words, the gas separator is capable of separating hydrogen from the mixed gas such that the JT coefficient of the second gas falls within this range. When the JT coefficient of the second gas immediately after separation falls within this range, the temperature of the second gas can be efficiently lowered by depressurizing the second gas. Therefore, the heat removal energy required for condensing the fuel gas can be reduced. Furthermore, when the JT coefficient of the second gas falls within this range, the membrane cost and the amount of raw material loss can be reduced. The JT coefficient of the second gas can be calculated by the sum of (the JT coefficients at the partial pressures of each gas component contained in the second gas) x (the composition ratio of the corresponding gas components).

[0035] The difference between the JT coefficient of the second gas and the JT coefficient of the mixed gas (JT coefficient of the second gas - JT coefficient of the mixed gas) is, for example, greater than 0 K / MPa and not greater than 13.1 K / MPa. In other words, the gas separator is capable of separating hydrogen from the mixed gas such that the difference between the JT coefficient of the second gas immediately after separation and the JT coefficient of the mixed gas immediately before separation is within this range. When the difference in the JT coefficient between the second gas and the mixed gas is adjusted in this manner, the temperature of the second gas can be lowered more efficiently by depressurizing the second gas. Furthermore, when the difference in the JT coefficient between the second gas and the mixed gas is within this range, membrane costs and raw material loss can be reduced.

[0036] Although not shown, the fuel gas condensation device 100 may include a plurality of reactors 1 and a plurality of gas separators 2. In this embodiment, the reactors 1 and the gas separators 2 are arranged alternately in the gas passage direction. The mixed gas discharged from the reactor 1 is supplied to the gas separator 2 located downstream of the reactor 1, and is separated into a first gas and a second gas in the gas separator 2. The second gas separated in the gas separator 2 is then supplied to the next reactor 1. If the raw material gas remains in the second gas, the raw material gas is used for the above-mentioned conversion reaction in the reactor 1. In one embodiment, the difference between the JT coefficient of the second gas separated in the gas separator 2 located most downstream in the gas passage direction among the plurality of gas separators 2 and the JT coefficient of the mixed gas supplied to the gas separator 2 is adjusted to be within the above-mentioned range of the JT coefficient difference.

[0037] The pressure reducing device 53 is typically disposed on the opposite side of the gas separator 2 from the reactor 1. In one embodiment, the pressure reducing device 53 is capable of reducing the pressure of the second gas between the gas separator 2 and the cooling device 31. That is, the pressure reducing device 53 is capable of performing a pressure reducing step of reducing the pressure of the second gas. In the illustrated example, the fuel gas condensation device 100 further includes a second connection line 52 that can supply the second gas separated in the gas separator 2 to the gas-liquid separator 32, and the pressure reducing device 53 is provided on the second connection line 52. The pressure reducing device 53 is typically a pressure reducing valve. More specifically, the pressure reducing device (pressure reducing valve 53) can reduce the pressure of the second gas to, for example, 5.0 MPa (absolute pressure) or less, or, for example, atmospheric pressure (0.1 MPa). This sufficiently reduces the temperature of the second gas, thereby further reducing the heat removal energy of the second gas.

[0038] The second gas is cooled by the cooling device 31 (cooling step). In one embodiment, the cooling device 31 is arranged on the opposite side of the pressure reducing device 53 from the gas separator 2, and cools the second gas after pressure reduction to a cooling temperature described below. In the illustrated example, the cooling device 31 is located downstream of the pressure reducing device 53 in the discharge direction of the second gas from the gas separator 2, and is provided on the second connection line 52. The cooling device 31 may have any appropriate configuration.

[0039] The cooling temperature in the cooling device 31 is typically equal to or lower than the condensation point (boiling point) of the reaction product (fuel gas). The cooling temperature is, for example, 50° C. or lower, preferably 40° C. or lower. On the other hand, the cooling temperature is, for example, 0° C. or higher, preferably 10° C. or higher.

[0040] When the second gas is decompressed and cooled, components contained in the second gas whose boiling points (condensation points) are equal to or higher than the cooling temperature (typically, fuel gas and part of by-product gas) can be stably liquefied to form a liquid fuel. Furthermore, if the cooling temperature is within the above range, the fuel gas can be liquefied more stably.

[0041] 2, the cooling device 31 may be provided between the gas separator 2 and the decompression device 53. That is, the cooling device 31 may be located upstream of the decompression device 53 in the discharge direction of the second gas from the gas separator 2. In this case, the second gas separated in the gas separator 2 is first cooled to the cooling temperature by the cooling device 31, and then decompressed by the decompression device 53. This also makes it possible to sufficiently liquefy, among the components contained in the second gas, those whose boiling points (condensation points) are equal to or higher than the cooling temperature, to produce a liquid fuel. That is, the cooling step may be performed after the decompression step or before the decompression step.

[0042] In one embodiment, the liquid fuel condensation device 100 further includes a gas-liquid separator 32. The gas-liquid separator 32 is disposed downstream of the gas separator 2 in the discharge direction of the second gas from the gas separator 2. In the illustrated example, the gas-liquid separator 32 is located downstream of the pressure reducing device 53 and the cooling device 31. The gas-liquid separator 32 can separate the liquid fuel condensed by the pressure reducing and cooling of the second gas from the gas components of the second gas that remain in a gaseous state even after the pressure reducing and cooling. In other words, the gas-liquid separator 32 can perform a gas-liquid separation process to separate the liquid fuel from the gas components. The gas-liquid separator 32 is typically a separation tank. The separation tank receives a mixture of the liquid fuel and gas components (typically, the feed gas and some by-products) whose boiling points (condensation points) are lower than the cooling temperature, and the mixture is stored therein to separate the liquid fuel from the gas components.

[0043] The liquid fuel contains at least a reaction product in a liquid state. The content of the reaction product in the liquid fuel is, for example, 15.0 mol % or more, preferably 20.0 mol % or more, and more preferably 50.0 mol % or more. On the other hand, the upper limit of the content of the reaction product in the liquid fuel is typically 100 mol %. In addition to the reaction product, the liquid fuel may also contain by-products in a liquid state. The content of the by-products in the liquid fuel is, for example, 85.0 mol % or less, preferably 80 mol % or less, and more preferably 50.0 mol % or less. On the other hand, the lower limit of the content of the by-products in the liquid fuel is typically 0 mol %. The liquid fuel is subjected to a by-product removal process as necessary. This can increase the content of the reaction product in the liquid fuel.

[0044] In one embodiment, the fuel gas condensation device 100 further includes a recovery line 9 capable of recovering the liquid fuel separated in the gas-liquid separator 32. In the illustrated example, the upstream end of the recovery line 9 is connected to the bottom of the separation tank 32. The downstream end of the recovery line 9 is connected to a fuel tank (not shown) capable of storing the liquid fuel.

[0045] In one embodiment, the fuel gas condensation apparatus 100 further includes a return line 6. The return line 6 is capable of returning gas components that remain in a gaseous state even after decompression and cooling of the second gas discharged from the gas separator 2. In other words, the fuel gas condensation apparatus 100 may be capable of performing a return step of returning the gas components to the reactor 1. In the illustrated example, the return line 6 is capable of returning the gas components separated in the gas-liquid separator 32 to the reactor 1. The upstream end of the return line 6 is connected to the top of the separation tank 32. The downstream end of the return line 6 is connected to the supply unit 4, not shown. This allows the gas components to be resupplied to the reactor and recycled as raw material gas.

[0046] In the above-described embodiment, a raw material gas containing hydrogen is supplied to reactor 1, and the mixed gas discharged from reactor 1 contains hydrogen that remains unreacted, but the present invention is not limited thereto. The mixed gas discharged from reactor 1 may contain hydrogen generated in reactor 1. In this case, the first gas separated in gas separator 2 contains hydrogen generated in reactor 1. In one embodiment, the reactor is capable of performing a water-gas shift reaction, and the mixed gas generated by the water-gas shift reaction is supplied from the reactor to the gas separator and separated into a first gas and a second gas.

[0047] As described above, the fuel gas condensation device 100 is capable of implementing the liquid fuel production method. The liquid fuel production method includes the gas separation step, the pressure reduction step, and the cooling step. In one embodiment, the liquid fuel production method further includes the reaction step. The liquid fuel production method may further include the gas-liquid separation step and / or the return step.

[0048] The specific configuration of the reactor will be described below.

[0049] B. Reactor The reactor 1 may have any suitable configuration. The shape of the reactor 1 is not particularly limited and may be, for example, a monolithic shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, a polygonal prism shape, or the like. The monolithic shape refers to a shape having a plurality of cells penetrating in the longitudinal direction, and is a concept that includes a honeycomb shape. Examples of the configuration of the reactor 1 include a membrane reactor, a fixed-bed reactor, a moving-bed reactor, a fluidized-bed reactor, a stirred tank reactor, a tower reactor, and a tubular reactor.

[0050] As shown in Fig. 3, in one embodiment, the reactor 1 is a tubular reactor 1a. The tubular reactor 1a typically has a gas inlet 15 through which the above-mentioned raw material gas flows in, a gas outlet 16 through which the mixed gas flows out, and a space 14 connecting these, and a catalyst 11 is accommodated in the space 14. The space 14 functions as a gas flow path. The gas inlet 15 is typically connected to the downstream end of a supply line 41. The gas outlet 16 is typically connected to the upstream end of a first connection line 51.

[0051] The catalyst 11 can promote the conversion reaction of the raw material gas. The catalyst 11 is preferably packed in the flow path 14. When the catalyst is in particulate form as in the illustrated example, the particle size (diameter) of the catalyst particles is, for example, 0.5 mm or more and 10 mm or less. The catalyst particles may be composed of catalyst alone, or may be configured such that the catalyst 11 is supported on carrier particles. The carrier particles are preferably porous particles.

[0052] Any appropriate catalyst depending on the desired conversion reaction can be used as the catalyst 11. Specifically, metal catalysts (copper, palladium, nickel, ruthenium, rhodium, platinum, etc.), oxide catalysts (zinc oxide, zirconia, gallium oxide, ceria, etc.), and catalysts made by combining these (copper-zinc oxide, copper-zinc oxide-alumina, copper-zinc oxide-chromium oxide-alumina, copper-cobalt-titania, nickel-ceria, nickel-alumina, ruthenium-ceria, and catalysts made by modifying these with palladium, etc.) can be used.

[0053] As shown in Fig. 4, in another embodiment, the reactor 1 is a membrane reactor 1b. The membrane reactor 1b typically includes a water vapor separation membrane 18. In the membrane reactor, while the reaction between carbon oxide and hydrogen proceeds, the by-produced water vapor is separated from the mixed gas containing the fuel gas and the raw material gas by the water vapor separation membrane. This can promote the reaction between carbon oxide and hydrogen.

[0054] The water vapor separation membrane 18 is permeable to water vapor, but is less permeable to components other than water vapor (such as hydrogen, carbon oxides, and fuel gas) than water vapor. Examples of water vapor separation membranes include inorganic membranes and organic membranes. Examples of inorganic membranes include zeolite membranes, silica membranes, alumina membranes, and composite membranes thereof. Among inorganic membranes, preferred is a zeolite membrane, and more preferred is an LTA-type zeolite membrane having a molar ratio (Si / Al) of silicon (Si) to aluminum (Al) of 1.0 or more and 3.0 or less. Examples of organic membranes include polyethylene (PE), polyvinylidene fluoride (PVDF), tetrafluoroethylene (PTFE), polypropylene (PP), cellulose acetate (CA), polyacrylonitrile (PAN), polyimide (PI), polysulfone (PS), and polyethersulfone (PES).

[0055] The membrane reactor 1b further includes a porous support 19. The porous support 19 supports the water vapor separation membrane 18. The porous support 19 is made of a porous material. Examples of the porous material include ceramic materials, metal materials, and resin materials, and preferably ceramic materials.

[0056] The membrane reactor 1b includes a first gas flow path 14 and a second gas flow path 17. The first gas flow path 14 can be described in the same manner as the space 14 of the tubular reactor 1a. The first gas flow path 14 communicates with the gas inlet 15 and the gas outlet 16, and contains the catalyst 11. In the illustrated example, the water vapor separation membrane 18 faces the first gas flow path 14. The second gas flow path 17 is located on the opposite side of the water vapor separation membrane 18 from the first gas flow path 14. Water vapor that has passed through the water vapor separation membrane 18 can flow into the second gas flow path 17. A sweep gas for sweeping water vapor may be supplied to the second gas flow path 17.

[0057] The membrane reactor 1b may have any suitable configuration. The shape of the membrane reactor 1b is not particularly limited. Examples of the shape of the membrane reactor 1b include a monolithic shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, and a polygonal prism shape. The monolithic shape refers to a shape having a plurality of cells penetrating in the longitudinal direction, and is a concept that includes a honeycomb shape. Examples of the configuration of the membrane reactor 1b include a fixed-bed reactor, a moving-bed reactor, a fluidized-bed reactor, a stirred tank reactor, a tower reactor, a tubular reactor, and a membrane reactor.

[0058] As shown in FIG. 5, in one embodiment, a membrane reactor 1 b includes a separation membrane composite 10 and a housing 12 .

[0059] The separation membrane composite 10 includes a porous support 19 having a monolith (honeycomb) shape and a water vapor separation membrane 18 .

[0060] The monolithic porous support 19 may have any suitable shape (overall shape). The porous support 19 typically has a cylindrical shape extending in a predetermined direction. Examples of the shape of the porous support 19 include a cylindrical shape with a circular bottom, an elliptical cylindrical shape with an elliptical bottom, a rectangular prism with a polygonal bottom, and a cylindrical shape with an irregular bottom. The outer diameter and length of the porous support 19 may be appropriately set depending on the purpose.

[0061] As shown in Fig. 6, in one embodiment, the porous support body 19 has a cylindrical shape. In the illustrated example, the porous support body 19 includes an outer wall 193 and a partition wall 192. The outer wall 193 and the partition wall 192 may be formed integrally or may be separate bodies. In the illustrated example, the outer wall 193 and the partition wall 192 are formed integrally.

[0062] The outer wall 193 forms the outer periphery of the columnar porous support 19 and has any appropriate cylindrical shape. The partition walls 192 are located inside the outer wall 193 and define a plurality of cells 191.

[0063] 5 , each of the multiple cells 191 typically extends in the longitudinal direction (axial direction) of the separation membrane composite 10 from a first end face E1 (upstream end face) to a second end face E2 (downstream end face) of the separation membrane composite 10. Each of the multiple cells 191 has any appropriate shape in a cross section perpendicular to the longitudinal direction. Examples of the cross-sectional shape of the cell 191 include a triangle, a rectangle, a pentagon, a polygon having hexagons or more, a circle, and an ellipse, with a circle being preferred.

[0064] The distance between the central axes of the multiple cells 191 is, for example, 0.3 mm to 20 mm. The cell density (i.e., the number of cells 191 per unit area) in the cross section perpendicular to the longitudinal direction of the separation membrane composite 10 can be appropriately set depending on the purpose. The cell density is, for example, 0.5 cells / cm ２ ~320 cells / cm ２ If the cell density is within this range, the strength and effective GSA (geometric surface area) of the porous support can be sufficiently ensured.

[0065] In the illustrated example, the water vapor separation membrane 18 is formed on the inner surface of each of the multiple cells 191. The water vapor separation membrane 18 may be formed on the entire inner surface of the cell 191, or may be formed on only a part of the inner surface of the cell 191.

[0066] In one embodiment, the first gas flow channel 14 described above is formed in a portion of the cross section of the cell 191 where the water vapor separation membrane 18 is not formed (typically the center portion). The first gas flow channel 14 extends from the first end face E1 (upstream end face) to the second end face E2 (downstream end face) of the separation membrane composite 10. The first gas flow channel 14 has any appropriate shape in a cross section perpendicular to the longitudinal direction. Examples of the cross-sectional shape of the first gas flow channel 14 include the same cross-sectional shape as the cell 191 described above. As described above, the first gas flow channel 14 contains the catalyst 11. For convenience, the catalyst 11 is omitted from FIGS. 5 and 6 .

[0067] The housing 12 accommodates the separation membrane composite 10. More specifically, the housing 12 accommodates the separation membrane composite 10 so that the first end face E1 and the second end face E2 of the separation membrane composite 10 are exposed.

[0068] In one embodiment, the housing 12 includes a sidewall 123 , an upstream end wall 121 , and a downstream end wall 122 .

[0069] The side wall 123 has any appropriate cylindrical shape. The shape of the side wall 123 is changed as appropriate depending on the shape of the porous support 19. The inner dimensions of the side wall 123 are larger than the outer dimensions of the porous support 19. In one embodiment, the side wall 123 of the housing 12 faces the outer wall 193 of the porous support 19 with a gap therebetween. The above-mentioned second flow path 17 is formed between the side wall 123 of the housing 12 and the outer wall 193 of the porous support 19. Gas components (typically water vapor) that have passed through the water vapor separation membrane 18 and the porous support 19 can flow into the second flow path 17. In the illustrated example, the side wall 123 has an opening 12a. The opening 12a is connected to the second flow path 17. The opening 12a allows gas components (typically water vapor) to be discharged from the second flow path 17.

[0070] The upstream end wall 121 is typically located at one end (upstream end) of the housing 12 in the axial direction of the side wall 123. In one embodiment, the upstream end wall 121 has an upstream opening 121a. The upstream opening 121a exposes the first end face E1 (upstream end face) of the separation membrane composite 10. The downstream end of the above-mentioned supply line 41 is connected to the upstream side wall 121 so as to communicate with the upstream opening 121a (see FIG. 1).

[0071] The downstream wall 122 is typically located at the other end (downstream end) of the housing 12 in the axial direction of the side wall 123. In one embodiment, the downstream wall 122 has a downstream opening 122a. The downstream opening 122a exposes the second end face E2 (downstream end face) of the separation membrane composite 10. The upstream end of the first connection line 51 is connected to the downstream wall 122 so as to communicate with the downstream opening 122a (see FIG. 1).

[0072] The condensation device according to the embodiment of the present invention can be used to condense various gases, and is particularly suitable for liquid fuels such as methanol, which are liquid at room temperature and pressure and therefore have a low vapor pressure, allowing for more effective condensation and facilitating separation of unreacted fuel.

[0073] REFERENCE SIGNS LIST 1 Reactor 2 Gas separator 31 Cooler 32 Gas-liquid separator 53 Pressure reducing device 100 Fuel gas condensation device

Claims

1. A condensation device comprising: a gas separator to which a mixed gas containing a fuel gas is supplied, the gas separator being capable of separating the mixed gas into a first gas and a second gas containing a fuel gas; a pressure reducing device capable of reducing the pressure of the second gas; and a cooling device capable of cooling the second gas; wherein the condensation device is configured such that the Joule-Thomson coefficient of the second gas is greater than the Joule-Thomson coefficient of the mixed gas by passing through the gas separator.

2. A condensation device as described in claim 1, further comprising at least one reactor arranged upstream of the gas separator in the supply direction of the mixed gas to the gas separator, wherein a raw material gas containing carbon oxides and hydrogen is supplied to the reactor, and the reactor is capable of discharging a mixed gas containing a fuel gas as a reaction product of the carbon oxides and hydrogen and the raw material gas remaining unreacted.

3. A condensation device as described in claim 2, wherein the gas separator is capable of separating the mixed gas supplied from the reactor into a first gas containing hydrogen as a main component and a second gas containing the fuel gas.

4. The condensation device according to claim 2, further comprising a return line capable of returning to the reactor a gas component of the second gas that remains in a gaseous state even after the pressure reduction and cooling.

5. A condensation device as described in claim 3, further comprising a gas-liquid separator arranged downstream of the gas separator in the discharge direction of the second gas from the gas separator, the gas-liquid separator being capable of separating liquid fuel condensed by depressurization and cooling of the second gas from gas components of the second gas that remain in a gaseous state even after depressurization and cooling.

6. A condensation device according to any one of claims 2 to 5, wherein the reactor is a membrane reactor.

7. A condensation device according to any one of claims 1 to 5, wherein the Joule-Thomson coefficient of the second gas is 15.9 K / MPa or less.

8. A condensation device according to any one of claims 1 to 5, wherein the liquid fuel contains an alcohol as a main component.

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