Liquid fuel manufacturing system and liquid fuel manufacturing method

Abstract

The main purpose of the present invention is to suppress deterioration of reaction yield in a conversion reaction for converting a raw material gas containing hydrogen gas and a carbon oxide into a liquid fuel. A liquid fuel production system according to an embodiment of the present invention is provided with: a liquid fuel synthesis unit for performing a conversion reaction for converting a raw material gas containing at least hydrogen gas and a carbon oxide into a liquid fuel; a raw material gas supply unit for supplying the raw material gas to the liquid fuel synthesis unit; and a raw material gas circulation unit that resupplies a remaining raw material gas containing the unreacted hydrogen gas, the carbon oxide, and the acidic by-product of the conversion reaction from the liquid fuel synthesis unit to the raw material gas supply unit, the raw material gas supply unit having: a mixing unit that mixes the hydrogen gas and the carbon oxide which are not reacted with each other and resupplies the remaining raw material gas to the raw material gas supply unit; a mixing step for mixing an amine compound with the remaining raw material gas in the presence of water vapor; and a moisture removal unit that removes the amine compound and a neutralized product of the acidic by-product together with condensed water of the water vapor.

Description

Technical Field

[0001] The invention relates to a liquid fuel production system and a liquid fuel production method. Background Art

[0002] In recent years, in order to achieve a carbon-neutral society, a scheme has been proposed to obtain carbon oxides as carbon resources and convert them into liquid fuels that are useful as industrial basic raw materials. For example, Patent Document 1 discloses a liquid fuel production system that uses a membrane reactor including a catalyst and a water vapor separation membrane to perform a conversion reaction of a raw gas containing hydrogen and carbon dioxide into methanol.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2018-8940 Summary of the invention

[0004] Technical problem to be solved by the invention In the above-mentioned conversion reaction of converting a raw gas containing hydrogen and carbon dioxide into a liquid fuel, there is a case where the reaction yield deteriorates. Specifically, in the above-mentioned conversion reaction, from the viewpoint of energy saving, the raw gas that has not reacted is recovered from the liquid fuel production system and is re-supplied as raw gas to the liquid fuel production system is recycled, but in the recycling of the raw gas, there is a case where the acidic byproducts generated in the conversion reaction accumulate as the number of cycles increases, resulting in a deterioration in the reaction yield.

[0005] A main object of the present invention is to suppress deterioration in reaction yield in a conversion reaction of a raw gas containing hydrogen and carbon oxides into a liquid fuel.

[0006] Technical solutions for solving technical problems [1] According to one aspect of the present invention, there is provided a liquid fuel manufacturing system, which comprises: a liquid fuel synthesis section, which performs a conversion reaction of converting a raw gas containing at least hydrogen and carbon oxides into a liquid fuel; a raw gas supply section, which supplies the raw gas to the liquid fuel synthesis section; and a raw gas circulation section, which supplies the remaining raw gas from the liquid fuel synthesis section to the raw gas supply section again, the remaining raw gas containing unreacted hydrogen and carbon oxides and acidic by-products of the conversion reaction, the raw gas supply section comprising: a mixing section, which mixes an amine compound with the remaining raw gas in the presence of water vapor; and a moisture removal section, which removes a neutralization product of the amine compound and the acidic by-products together with condensed water of the water vapor.

[0007] [2] In the liquid fuel production system described in [1] above, the neutralization raw material gas containing the amine compound may be mixed with the remaining raw material gas in the mixing section.

[0008] [3] In the liquid fuel production system described in [1] above, the raw material gas may further contain nitrogen, and the amine compound may be ammonia produced from the hydrogen and the nitrogen in the liquid fuel synthesis section.

[0009] [4] The liquid fuel production system described in [2] above may also include a gas recovery unit for recovering carbon dioxide from the atmosphere or biogas, and the gas containing carbon dioxide supplied from the gas recovery unit is used as a constituent component of the neutralization raw gas.

[0010] [5] In the liquid fuel production system described in [2] or [4] above, the liquid fuel synthesis unit may also have a water vapor separation membrane that allows at least water vapor to pass through, and separates the permeable side gas and the non-permeable side gas, the permeable side gas is gas that has passed through the water vapor separation membrane from the non-permeable side to the permeable side, and contains water vapor as a by-product of the above-mentioned conversion reaction, and the non-permeable side gas is gas that has not passed through the water vapor separation membrane, and contains the above-mentioned liquid fuel, unreacted hydrogen and the above-mentioned carbon oxides, and the above-mentioned acidic by-products. In addition, the liquid fuel production system may also have a purge gas supply unit, which supplies a purge gas that purges the above-mentioned permeable side gas and contains an amine compound to the above-mentioned permeable side of the above-mentioned liquid fuel synthesis unit, and the above-mentioned permeable side gas and the above-mentioned purge gas flowing out of the above-mentioned liquid fuel synthesis unit may also be supplied to the above-mentioned mixing unit.

[0011] [6] In the liquid fuel production system described in [5] above, the purge gas may further contain carbon oxides and / or hydrogen.

[0012] [7] In the liquid fuel production system described in [5] or [6] above, the concentration of the amine compound in the purge gas may be 10 ppm or more.

[0013] [8] In the liquid fuel production system described in [3] above, the liquid fuel synthesis unit may also have a water vapor separation membrane that allows at least water vapor and ammonia to pass through, and separates the permeable side gas from the non-permeable side gas, the permeable side gas is gas that has passed through the water vapor separation membrane from the non-permeable side to the permeable side, and contains water vapor and the ammonia as by-products of the conversion reaction, and the non-permeable side gas is gas that has not passed through the water vapor separation membrane, and contains the liquid fuel, unreacted hydrogen and carbon oxides, and the acidic by-products. In addition, the liquid fuel production system may also have a purge gas supply unit that supplies a purge gas for purging the permeable side gas to the permeable side of the liquid fuel synthesis unit, and the permeable side gas and the purge gas flowing out of the liquid fuel synthesis unit may also be supplied to the mixing unit.

[0014] [9] In the liquid fuel production system described in [8] above, the ammonia concentration in the mixed gas of the permeate-side gas and the purge gas may be 10 ppm or more.

[0015]

[10] In the liquid fuel production system described in [2] or [4] above, the liquid fuel synthesis unit may also have a liquid fuel separation membrane that allows at least liquid fuel to pass through, and separates the permeation side gas and the non-permeation side gas, the permeation side gas is gas that has passed through the liquid fuel separation membrane from the non-permeation side to the permeation side and contains the liquid fuel, and the non-permeation side gas is gas that has not passed through the liquid fuel separation membrane and contains water vapor as a by-product of the conversion reaction, unreacted hydrogen and carbon oxides, and the acidic by-products. In addition, the liquid fuel production system may also have a purge gas supply unit that supplies a purge gas that purges the permeation side gas and contains an amine compound to the permeation side of the liquid fuel synthesis unit, and the purge gas flowing out of the liquid fuel synthesis unit may also be supplied to the mixing unit.

[0016]

[11] In the liquid fuel production system described in

[10] above, the purge gas may further contain carbon oxides and / or hydrogen.

[0017]

[12] In the liquid fuel production system described in

[10] or

[11] above, the concentration of the amine compound in the purge gas may be 10 ppm or more.

[0018]

[13] In the liquid fuel production system described in [3] above, the liquid fuel synthesis unit may also have a liquid fuel separation membrane that allows at least liquid fuel and ammonia to pass through, and separates the permeation side gas and the non-permeation side gas, the permeation side gas is gas that has passed through the liquid fuel separation membrane from the non-permeation side to the permeation side, and contains the liquid fuel and the ammonia, the non-permeation side gas is gas that has not passed through the liquid fuel separation membrane, and contains water vapor as a by-product of the conversion reaction, unreacted hydrogen and carbon oxides, and the acidic by-products. In addition, the liquid fuel production system may also have a purge gas supply unit that supplies a purge gas for purging the permeation side gas to the permeation side of the liquid fuel synthesis unit, and the permeation side gas and the purge gas flowing out of the liquid fuel synthesis unit may also be supplied to the mixing unit.

[0019]

[14] In the liquid fuel production system described in

[13] above, the ammonia concentration in the mixed gas of the permeate-side gas and the purge gas may be 10 ppm or more.

[0020]

[15] In the liquid fuel production system described in [2] above, the liquid fuel synthesis unit may also have: a first gas flow path, which is provided with a catalyst for promoting the above-mentioned conversion reaction; and a second gas flow path, for circulating a temperature-regulating gas for regulating the temperature of the above-mentioned first gas flow path. In addition, the liquid fuel production system may also have a temperature-regulating gas supply unit, which supplies a temperature-regulating gas containing an amine compound to the above-mentioned second gas flow path of the above-mentioned liquid fuel synthesis unit, and the above-mentioned temperature-regulating gas flowing out of the above-mentioned liquid fuel synthesis unit may also be supplied to the above-mentioned mixing unit.

[0021]

[16] In the liquid fuel production system described in

[15] above, the temperature control gas may further contain carbon oxides and / or hydrogen.

[0022]

[17] In the liquid fuel production system described in

[15] above, the concentration of the amine compound in the temperature control gas may be 10 ppm or more.

[0023]

[18] According to another aspect of the present invention, a method for producing a liquid fuel is provided, the method comprising the following steps: supplying the raw gas to a liquid fuel synthesis unit comprising a catalyst, the catalyst promoting a conversion reaction from a raw gas containing at least hydrogen and carbon oxides to a liquid fuel; not only promoting the conversion reaction, but also recovering a remaining raw gas from the liquid fuel synthesis unit, the remaining raw gas containing unreacted hydrogen and carbon oxides and acidic by-products; removing the acidic by-products from the remaining raw gas; and supplying the remaining raw gas after the acidic by-products are removed as a part of the raw gas to the liquid fuel synthesis unit again, the step of removing the acidic by-products from the remaining raw gas comprising the following steps: mixing an amine compound with the remaining raw gas in the presence of water vapor, and neutralizing the acidic by-products with the amine compound.

[0024]

[19] In the method for producing liquid fuel described in

[18] above, the step of removing the above-mentioned acidic by-product from the above-mentioned residual raw gas may also include the following step: mixing the neutralization raw gas containing the above-mentioned amine compound that is supplied to the above-mentioned liquid fuel synthesis section and circulated in the above-mentioned liquid fuel synthesis section with the above-mentioned residual raw gas.

[0025]

[20] In the method for producing a liquid fuel described in

[18] above, the raw gas may further contain nitrogen, and the amine compound may be ammonia generated from the hydrogen and the nitrogen in the liquid fuel synthesis section.

[0026]

[21] In the method for producing a liquid fuel described in

[19] above, the neutralization raw gas may be prepared using a gas containing carbon dioxide recovered from the atmosphere or biogas.

[0027]

[22] In the method for producing liquid fuel described in

[19] or

[21] above, the liquid fuel synthesis section may have a water vapor separation membrane that allows at least water vapor to pass through, and water vapor as a by-product of the conversion reaction may be allowed to pass from the non-permeable side to the permeable side of the water vapor separation membrane and purged with a purge gas containing the amine compound and recovered as waste gas from the liquid fuel synthesis section, or the waste gas may be mixed with the remaining raw gas and the acidic by-product in the remaining raw gas may be neutralized with the amine compound.

[0028]

[23] In the method for producing liquid fuel described in

[19] or

[21] above, the liquid fuel synthesis unit may have a liquid fuel separation membrane that allows at least the liquid fuel to pass through, and the liquid fuel may be allowed to pass from the non-permeable side to the permeable side of the liquid fuel separation membrane and purged with a purge gas containing the amine compound, and recovered as a product gas from the liquid fuel synthesis unit, and water vapor as a by-product of the conversion reaction is recovered, and the product gas is separated into the liquid fuel and the purge gas, or the purge gas, the remaining raw gas and the water vapor are mixed, and the acidic by-products in the remaining raw gas are neutralized with the amine compound.

[0029]

[24] In the method for producing liquid fuel described in

[19] or

[21] above, a temperature-regulating gas containing the above-mentioned amine compound for regulating the reaction temperature of the above-mentioned conversion reaction may be circulated in the above-mentioned liquid fuel synthesis section, the above-mentioned temperature-regulating gas circulated in the above-mentioned liquid fuel synthesis section may be mixed with the above-mentioned residual raw gas, and the above-mentioned acidic by-product in the above-mentioned residual raw gas may be neutralized with the above-mentioned amine compound.

[0030]

[25] In the method for producing liquid fuel described in

[20] above, the liquid fuel synthesis section may have a water vapor separation membrane that allows at least water vapor and ammonia to pass through, and the water vapor and the ammonia that are by-products of the conversion reaction may be allowed to pass from the non-permeable side to the permeable side of the water vapor separation membrane and purged with a purge gas to be recovered from the liquid fuel synthesis section as waste gas, or the waste gas may be mixed with the remaining raw gas and the acidic by-products in the remaining raw gas may be neutralized with the ammonia.

[0031]

[26] In the method for producing liquid fuel described in

[20] above, the liquid fuel synthesis unit may have a liquid fuel separation membrane that allows at least the liquid fuel and ammonia to pass through. The liquid fuel and the ammonia may be allowed to pass from the non-permeable side to the permeable side of the liquid fuel separation membrane and purged with a purge gas, and recovered from the liquid fuel synthesis unit as a product gas, and water vapor as a by-product of the conversion reaction may be recovered together with the remaining raw gas. The liquid fuel may be separated from the product gas and then mixed with the remaining raw gas and the water vapor, and the acidic by-products in the remaining raw gas may be neutralized with the ammonia.

[0032] Effects of the Invention According to the liquid fuel manufacturing system based on the embodiment of the present invention, the acidic byproducts produced in the conversion reaction are removed by neutralization during the circulation of the raw gas, so that the deterioration of the above reaction yield can be suppressed. In addition, corrosion may occur in the liquid fuel manufacturing system due to the acidic byproducts, but according to the liquid fuel manufacturing method based on the embodiment of the present invention, such corrosion can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic configuration diagram of a liquid fuel production system according to one embodiment of the present invention.

[0034] Figure 2 It is a schematic configuration diagram of a liquid fuel production system according to one embodiment of the present invention.

[0035] Figure 3 It is a schematic configuration diagram of a liquid fuel production system according to one embodiment of the present invention.

[0036] Figure 4 It is a schematic configuration diagram of a liquid fuel production system according to one embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the accompanying drawings schematically show the width, thickness, shape, etc. of each part compared with the embodiments, but this is only an example and does not limit the interpretation of the present invention.

[0038] A. Liquid fuel production system A liquid fuel production system according to an embodiment of the present invention includes: A liquid fuel synthesis section that performs a conversion reaction from a raw gas containing at least hydrogen and carbon oxides to a liquid fuel; a raw gas supply unit that supplies the raw gas to the liquid fuel synthesis unit; and a raw gas circulation unit for resupplying the remaining raw gas from the liquid fuel synthesis unit to the raw gas supply unit, wherein the remaining raw gas contains the unreacted hydrogen and carbon oxides and the acidic byproducts of the conversion reaction, The raw material gas supply unit includes: a mixing unit that mixes the amine compound with the remaining raw material gas in the presence of water vapor; and A moisture removal unit removes a neutralized product of the amine compound and the acidic by-product together with condensed water of the water vapor.

[0039] According to the liquid fuel production system based on the embodiment of the present invention, the acidic by-products contained in the remaining raw gas are neutralized with an amine compound in the presence of water vapor, and the generated neutralized product can be removed together with condensed water of the water vapor (also referred to as water vapor for neutralization removal).

[0040] In one embodiment, the liquid fuel synthesis section includes a separation membrane that separates the liquid fuel from water vapor (also referred to as by-product water vapor) that is a by-product of the reforming reaction.

[0041] Figure 1 It is a schematic configuration diagram of a liquid fuel production system according to one embodiment of the present invention.

[0042] Figure 1 The liquid fuel production system 1A shown comprises: a liquid fuel synthesis section 10, which carries out a conversion reaction from a raw gas containing at least hydrogen and carbon oxides into a liquid fuel; a raw gas supply section 20, which supplies raw gas to the liquid fuel synthesis section 10; and a raw gas circulation section 30, which supplies the remaining raw gas from the liquid fuel synthesis section 10 to the raw gas supply section 20 again, and the remaining raw gas contains unreacted hydrogen and carbon oxides and acidic by-products of the above-mentioned conversion reaction.

[0043] The liquid fuel synthesis section 10 has a water vapor separation membrane 14 that allows water vapor to pass through, and separates the permeation side gas and the non-permeation side gas. The permeation side gas is gas that has passed through the water vapor separation membrane 14 from the non-permeation side to the permeation side and contains water vapor as a by-product of the above-mentioned conversion reaction. The non-permeation side gas is gas that has not passed through the water vapor separation membrane 14 and contains liquid fuel, unreacted hydrogen and carbon oxides, and acidic by-products.

[0044] The liquid fuel production system 1A further includes a purge gas supply unit 40 that supplies a gas for purging the permeate-side gas to the liquid fuel synthesizing unit 10 .

[0045] The raw material gas supply unit 20 includes a mixing unit 24 for mixing the amine compound with the remaining raw material gas in the presence of water vapor, and a moisture removal unit 26 for removing a neutralized product of the amine compound and the acidic byproduct together with condensed water of the water vapor.

[0046] According to the liquid fuel production system 1A, by using a gas containing an amine compound (raw gas for neutralization) as a purge gas, the purge gas (raw gas for neutralization) flowing out of the liquid fuel synthesis unit 10, the water vapor contained in the permeate side gas, and the remaining raw gas contained in the non-permeate side gas are mixed, thereby enabling the acidic by-products in the remaining raw gas to be neutralized by the amine compound in the presence of water vapor.

[0047] In this specification, liquid fuel refers to a fuel that is in a liquid state at room temperature and pressure, or a fuel that can be liquefied under room temperature and pressure. Examples of fuels that are in a liquid state at room temperature and pressure include methanol, ethanol, n H 2（m-2n） (m is an integer less than 90, n is an integer less than 30), and mixtures thereof. Examples of the fuel that can be liquefied under normal temperature and pressure include propane, butane, and mixtures thereof.

[0048] As an example of the above-mentioned conversion reaction, the reaction formula of a reaction that may occur when synthesizing methanol by catalytic hydrogenation of a raw material gas containing carbon monoxide, carbon dioxide and hydrogen in the presence of a catalyst is as follows.

[0049] 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) The above reaction is a balanced reaction. In order to improve both the conversion rate and the reaction rate, it is preferably reacted at high temperature and high pressure. The reaction temperature is, for example, 180°C or more, preferably 200°C or more and 350°C or less, and more preferably 200°C or more and 300°C or less. The reaction pressure is, for example, 1MPa(G) or more, preferably 2.0MPa(G) or more and 6.0MPa(G) or less, and more preferably 2.5MPa(G) or more and 4.0MPa(G) or less. The liquid fuel is in a gaseous state at the time of synthesis, and the gaseous state is maintained at least until it flows out of the liquid fuel synthesis unit.

[0050] A-1. Liquid fuel synthesis unit The liquid fuel synthesis unit 10 is a so-called membrane reactor for converting raw gas into liquid fuel. The shape of the liquid fuel synthesis unit 10 is not particularly limited, and can be, for example, a monolithic shape, a flat plate shape, a tubular shape, a cylindrical shape, a cylindrical shape, a polygonal column shape, etc. The so-called monolithic shape refers to a shape having a plurality of cells penetrating in the length direction, and is a concept including a honeycomb shape.

[0051] The liquid fuel synthesis section 10 includes a catalyst 12, a water vapor separation membrane 14, a non-permeable side space 10A, and a permeable side space 10B. In the example shown in the figure, the water vapor separation membrane 14 is supported by a porous support 16. The liquid fuel synthesis section 10 is provided with a first supply port s1 and a first discharge port d1 communicated via the non-permeable side space 10A, and a second supply port s2 and a second discharge port d2 communicated via the permeable side space 10B. The liquid fuel synthesis section 10 preferably has heat resistance and pressure resistance suitable for the desired synthesis conditions of the liquid fuel.

[0052] The catalyst 12 promotes the conversion reaction from the raw gas to the liquid fuel. The catalyst is arranged in the non-permeable side space 10A which is the non-permeable side of the water vapor separation membrane 14. The catalyst is preferably filled in the non-permeable side space 10A, but can also be arranged on the surface of the water vapor separation membrane 14 in a layered or island shape. In the case where the catalyst is in a particle shape as shown in the example, the particle size (diameter) of the catalyst particles can be set to, for example, 0.5 mm or more and 10 mm or less. The catalyst particles can be composed of only the catalyst, or can be a structure in which the catalyst is supported on the carrier particles. The carrier particles are preferably porous particles.

[0053] As the catalyst, any catalyst suitable for the conversion reaction to the desired liquid fuel can be used. Specifically, metal catalysts (copper, palladium, etc.), oxide catalysts (zinc oxide, zirconium oxide, gallium oxide, etc.), and composite catalysts thereof (copper-zinc oxide, copper-zinc oxide-alumina, copper-zinc oxide-chromium oxide-alumina, copper-cobalt-titanium dioxide, and catalysts modified with palladium thereof, etc.) can be used.

[0054] The water vapor separation membrane 14 allows water vapor, which is a byproduct of the reforming reaction from the raw material gas to the liquid fuel, to pass therethrough, thereby shifting the reaction equilibrium of the above formula (2) toward the product side by utilizing the equilibrium shift effect.

[0055] The molecular diameter of water (0.26 nm) is close to the molecular diameter of hydrogen (0.296 nm), so not only water vapor as a byproduct of the reforming reaction but also a part of hydrogen contained in the raw material gas can permeate the water vapor separation membrane 14 .

[0056] The water vapor separation membrane 14 preferably has a thermal conductivity of 100 nmol / (s·Pa·m 2 ) or more. The water vapor permeability coefficient can be obtained by a known method (see Ind. Eng. Chem. Res., 40, 163-175 (2001)).

[0057] The water vapor separation membrane 14 preferably has a separation factor of 100 or more. The larger the separation factor, the easier it is for water vapor to pass through, and the harder it is for components other than water vapor (hydrogen, carbon oxides, oxygen, and liquid fuel, etc.) to pass through. The separation factor can be obtained by a known method (see Fig. 1 of "Separation and Purification Technology 239 (2020) 116533").

[0058] As the water vapor separation membrane 14, an inorganic membrane can be used. The inorganic membrane has heat resistance, pressure resistance, and water vapor resistance, so it is preferred. As the inorganic membrane, zeolite membrane, silica membrane, alumina membrane, and composite membranes thereof can be cited. For example, an LTA-type zeolite membrane having a molar ratio (Si / Al) of silicon element (Si) to aluminum element (Al) of 1.0 or more and 3.0 or less has excellent water vapor permeability, so it is preferred.

[0059] The zeolite membrane used as the water vapor separation membrane 14 can be obtained by the production method described in, for example, Japanese Patent Application Publication No. 2004-66188. The silicon dioxide membrane used as the water vapor separation membrane 14 can be obtained by the production method described in, for example, International Publication No. 2008 / 050812.

[0060] The porous support 16 is made of a porous material. As the porous material, ceramic materials, metal materials, resin materials, and composite members thereof can be used, and ceramic materials are particularly preferred. As the aggregate of the ceramic material, alumina (Al 2 O 3 ), titanium dioxide (TiO 2 )、Mullite(Al 2 O 3 ·SiO 2 )、Ceramic particles、Cordierite(Mg 2 Al 4 Si 5 O 18 ), and composite materials containing two or more of them, etc., if the availability, clay stability and corrosion resistance are taken into consideration, alumina is preferred. As an inorganic binder for the ceramic material, at least one of titanium dioxide, mullite, sinterable alumina, silicon dioxide, glass frit, clay mineral, and sinterable cordierite can be used. The ceramic material may not contain an inorganic binder.

[0061] The average pore size of the porous support can be set to 5 μ m and above and 25 μThe average pore size of the porous support can be measured by mercury intrusion. The porosity of the porous support can be set to 25% or more and 50% or less. The average particle size of the porous material constituting the porous support can be set to 1 μ m or more and 100 μ In the present embodiment, the average particle size refers to the arithmetic mean of the maximum diameters of 30 particles to be measured (selected at random) measured by cross-sectional microstructure observation using a SEM (Scanning Electron Microscope).

[0062] The non-permeable side space 10A is a space on the non-permeable side of the water vapor separation membrane 14. The raw gas supplied from the raw gas supply unit 20 flows into the non-permeable side space 10A through the first supply port s1. Liquid fuel is synthesized from the raw gas at the catalyst 12, and the generated liquid fuel and the unreacted raw gas (residual raw gas) flow out from the non-permeable side space 10A to the raw gas circulation unit 30 through the first discharge port d1 as non-permeable side gas. The non-permeable side gas contains liquid fuel and residual raw gas. The residual raw gas contains acidic by-products in addition to unreacted hydrogen and carbon oxides. Acidic by-products refer to by-products that act as so-called Bronsted acids among the by-products of the above-mentioned conversion reaction. Examples of acidic by-products include formic acid, methyl formate, and the like.

[0063] The permeate-side space 10B is a space on the permeate side of the water vapor separation membrane 14. Water vapor generated in the above-mentioned reforming reaction and hydrogen gas in the raw material gas pass through the water vapor separation membrane 14 and flow into the permeate-side space 10B.

[0064] According to the liquid fuel synthesis unit 10 of the above-mentioned structure, the above-mentioned conversion reaction is promoted by the supply of raw gas, and the permeable side gas and the non-permeable side gas can be separated. The above-mentioned permeable side gas is a gas that has passed through the water vapor separation membrane from the non-permeable side space 10A to the permeable side space 10B and contains water vapor as a by-product of the above-mentioned conversion reaction. The above-mentioned non-permeable side gas is a non-permeable gas and contains liquid fuel, unreacted hydrogen and carbon oxides, and acidic by-products.

[0065] In addition, the purge gas is supplied to the permeate-side space 10B through the second supply port s2 from the purge gas supply unit 40. The permeate-side gas and the purge gas flow out from the permeate-side space 10B to the raw gas supply unit 20 through the second discharge port d2 as exhaust gas.

[0066] A-2. Purge gas supply unit The purge gas supply unit 40 is disposed upstream of the permeation side space 10B and includes: a purge gas storage unit 42; a purge gas supply pipe 44 connecting the purge gas storage unit 42 and the second inlet s2 of the liquid fuel synthesis unit 10; and a heating unit 46 interposed in the purge gas supply pipe 44.

[0067] The purge gas storage unit 42 stores the purge gas. The purge gas is heated to a desired temperature (eg, 150° C. to 350° C.) in the heating unit 46 and then supplied to the liquid fuel synthesis unit 10 from the second inlet s2. The heating unit 46 is not particularly limited as long as it can heat the purge gas.

[0068] The purge gas contains an amine compound, and preferably also contains one or both of hydrogen and carbon oxides. As will be described later regarding the raw material gas supply unit, in this embodiment, the raw material gas is prepared using a mixed gas of an exhaust gas containing a purge gas and a remaining raw material gas. Here, by making the purge gas contain an amine compound, the acidic byproducts in the remaining raw material gas can be neutralized and removed by the amine compound.

[0069] As the amine compound, any appropriate amine compound can be used as long as the effects of the present invention can be obtained. The amino group contained in the amine compound other than ammonia may be a primary amino group, a secondary amino group, a tertiary amino group, or a combination of two or more thereof.

[0070] In one embodiment, an amine compound having a boiling point of 100° C. to 500° C., preferably 170° C. to 350° C. is used. Such an amine compound can maintain a good gas state in the purge gas.

[0071] Specific examples of the amine compound include ammonia, polyethyleneimine, monoethanolamine, diethanolamine, triethanolamine, tetraethylene pentamine, methyldiethanolamine, dibutylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, hexylenediamine, benzylamine, N-(3-aminopropyl)diethanolamine, aminopropyltrimethoxysilane, polyethyleneamine, 3-aminopropyltriethoxysilane, aminosilane coupling agents such as N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, etc. The amine compound can be used alone or in combination.

[0072] The concentration of the amine compound in the purge gas is not limited as long as the effect of the present invention can be obtained. From the viewpoint of neutralization of the acidic byproducts, the concentration of the amine compound in the purge gas is, for example, 10 ppm or more. In addition, there is no particular upper limit on the concentration of the amine compound, but since the catalyst is hindered by the base, it can also be appropriately adjusted to a concentration that prevents the catalyst from being reduced. The above-mentioned concentration of the amine compound in the purge gas is the concentration of the amine compound in the purge gas at the second supply port s2 of the liquid fuel synthesis unit.

[0073] In one embodiment, the purge gas contains hydrogen or carbon oxides as a main component, preferably contains hydrogen as a main component. It should be noted that containing hydrogen or carbon oxides as a main component means that the concentration of hydrogen or carbon oxides is the highest in the purge gas. The hydrogen concentration in the purge gas is, for example, about 50% by volume or more and 90% by volume or less, preferably 65% ​​by volume or more and 80% by volume or less. The carbon oxide concentration is, for example, about 10% by volume or more and less than 50% by volume, preferably 20% by volume or more and 35% by volume or less. In the case where the purge gas is substantially composed of hydrogen, carbon oxides and amine compounds, the exhaust gas can be appropriately reused as a part of the raw gas without separating it into hydrogen and purge gas derived from the raw gas.

[0074] A-3. Raw gas circulation unit The raw gas circulation section 30 includes a non-permeated side gas recovery pipe 31, a first condenser 32, a first drain trap 33, a liquid fuel recovery pipe 34, and a raw gas circulation pipe 35. One end of the non-permeated side gas recovery pipe 31 is connected to the first outlet d1 of the liquid fuel synthesis section 10, and the other end is connected to the first condenser 32. One end of the raw gas circulation pipe 35 is connected to the first drain trap 33, and the other end is connected to the raw gas supply section 20 (more specifically, the mixing section 24).

[0075] The non-permeated gas recovered from the liquid fuel synthesizing unit 10 via the non-permeated gas recovery pipe 31 is supplied to the first condenser 32 , whereby the liquid fuel is condensed (liquefied). The liquefied liquid fuel is separated from the remaining raw gas by the first drain 33 and recovered from the liquid fuel recovery pipe 34 .

[0076] The non-permeated side gas (in other words, the remaining raw gas) after the liquid fuel is separated contains a small amount of acidic byproducts in addition to unreacted hydrogen and carbon oxides. The remaining raw gas is supplied to the raw gas supply unit 20 (more specifically, the mixing unit 24) through the raw gas circulation pipe 35.

[0077] As shown in the example in the figure, a purge valve 36 may be provided on the raw gas circulation pipe 35. The purge valve 36 is provided at one or more positions of the raw gas circulation pipe 35 to discharge a part of the excess raw gas flowing in the raw gas circulation pipe 35 to the outside.

[0078] A-4. Raw material gas supply unit The raw gas supply unit 20 includes a raw gas supply pipe 22 for neutralization, a mixing unit 24, a moisture removal unit 26, and a pressurizing unit 28. The moisture removal unit 26 includes a second condenser 26a, a second drain trap 26b, and a moisture recovery pipe 26c. One end of the raw gas supply pipe 22 for neutralization is connected to the second outlet d2 of the liquid fuel synthesis unit 10, and the other end is connected to the second condenser 26a of the moisture removal unit 26. In addition, the raw gas circulation pipe 35 is connected to the raw gas supply pipe 22 for neutralization in a manner of merging upstream of the moisture removal unit 26, and the connection portion is set as the mixing unit 24. It should be noted that the mixing unit can be any structure as long as it can mix the raw gas for neutralization with the remaining raw gas. For example, a tank (mixing unit) can be set upstream of the moisture removal unit 26, and the raw gas supply pipe 22 for neutralization and the raw gas circulation pipe 35 can be independently connected to the tank, and the raw gas for neutralization and the remaining raw gas can be mixed inside the tank.

[0079] According to the above structure, the exhaust gas (permeate side gas and purge gas) recovered from the liquid fuel synthesis unit 10 via the neutralization raw gas supply piping 22 is mixed with the remaining raw gas upstream of the moisture removal unit 26. As a result, the acidic byproducts contained in the remaining raw gas are neutralized by the amine compound (amine compound derived from the purge gas) contained in the exhaust gas. In addition, if the mixed gas of the exhaust gas and the remaining raw gas is supplied to the second condenser 26a, the water vapor (water vapor derived from the permeate side gas) contained in the exhaust gas is condensed, and the neutralized product generated by the above neutralization is transferred (dissolved) into the condensed water. As a result of the increase in the amount of water and condensed water generated during the neutralization, the amount of dissolved neutralized product increases, so the neutralized product can be effectively transferred to the condensed water. The condensed water containing the neutralized product is separated from the remaining gas components by the second drain trap 26b and recovered (removed) from the moisture recovery piping 26c. The concentration of amine compounds in the exhaust gas (the concentration of amine compounds at the second discharge port d2 of the liquid fuel synthesis unit) is, for example, 10 ppm or more. The upper limit of the concentration of the amine compound in the exhaust gas is not particularly limited, but since the catalyst is inhibited by the base, the concentration can be appropriately adjusted to prevent the catalyst action from being reduced.

[0080] The gas component after separation of condensed water and neutralized product is pressurized and heated in the pressurizing section 28, and then supplied as raw gas to the non-permeable side space 10A of the liquid fuel synthesis section 10. The raw gas is a gas that recycles the remaining raw gas, but the accumulation of acidic byproducts is suppressed as the number of cycles increases. In addition, although not shown in the figure, hydrogen and / or carbon oxides can be mixed in the gas component after separation of condensed water and neutralized product to prepare the raw gas into a desired composition as needed.

[0081] As described above, the raw material gas contains at least hydrogen and carbon oxides. The carbon oxide concentration in the raw material gas is, for example, 10% by volume or more and 40% by volume or less, preferably 20% by volume or more and 30% by volume or less. The hydrogen concentration in the raw material gas is, for example, 60% by volume or more and 90% by volume or less, preferably 70% by volume or more and 80% by volume or less.

[0082] A-5. Modification 1 Figure 2 It is a schematic configuration diagram of a liquid fuel production system according to another embodiment of the present invention.

[0083] Figure 2 The liquid fuel production system 1B shown in the figure includes a liquid fuel synthesis unit 10, a raw gas supply unit 20, a raw gas circulation unit 30, and a purge gas supply unit 40. The liquid fuel production system 1B and Figure 1 The liquid fuel production system 1A shown is different in that the purge gas supply unit 40 includes a carbon dioxide recovery unit 41 , a carbon dioxide supply pipe 43 , a hydrogen generation unit 45 , a hydrogen supply pipe 47 , a purge gas supply pipe 44 , and a heating unit 46 .

[0084] For example, the carbon dioxide recovery unit 41 includes a carbon dioxide adsorbent material, which adsorbs carbon dioxide by contacting with a gas containing carbon dioxide, and desorbs carbon dioxide by heating, reducing pressure, etc., and uses the carbon dioxide adsorbent material to recover a gas containing carbon dioxide (carbon dioxide concentrated gas) at a concentration higher than that of the gas containing carbon dioxide. More specifically, the carbon dioxide recovery unit 41 adsorbs carbon dioxide by contacting the gas containing carbon dioxide with the carbon dioxide adsorbent material, and then desorbs carbon dioxide by heating and / or reducing pressure on the carbon dioxide adsorbent material, and the desorbed carbon dioxide is sucked by a pump, etc., so that the carbon dioxide concentrated gas can be recovered. In one embodiment, the carbon dioxide recovery unit 41 is a carbon dioxide recovery device using direct air recovery (DAC) technology. As a carbon dioxide adsorbent, an amine compound is representatively used. A specific example of the amine compound is as described above with respect to the purge gas. Due to the mixing of the carbon dioxide adsorbent material when recovering the carbon dioxide concentrated gas, the carbon dioxide concentrated gas can contain a trace amount of carbon dioxide adsorbent, that is, an amine compound. In addition, the carbon dioxide concentrated gas can contain nitrogen from the atmosphere.

[0085] In addition, for example, the carbon dioxide recovery unit 41 may be a carbon dioxide recovery device that uses a separation membrane to recover carbon dioxide from biogas. Biogas is a gas produced by fermentation (methane fermentation) of biomass such as kitchen waste, paper waste, and livestock feces and urine. The main components of biogas are methane and carbon dioxide, and may further contain trace amounts of nitrogen and the like.

[0086] The hydrogen generation unit 45 is, for example, hydrogen production equipment using water electrolysis technology.

[0087] The carbon dioxide supply pipe 43 connects the carbon dioxide recovery unit 41 to the heating unit 46, and the hydrogen supply pipe 47 connects the hydrogen generation unit 45 to the carbon dioxide supply pipe 43. Thus, the carbon dioxide concentrated gas supplied from the carbon dioxide recovery unit 41 is mixed with the hydrogen supplied from the hydrogen generation unit 45 to generate a purge gas. After the purge gas is heated in the heating unit 46, it is supplied to the liquid fuel synthesis unit 10 via the purge gas supply pipe 44. That is, the carbon dioxide concentrated gas is supplied to the raw gas supply unit 10 as a constituent component of the purge gas (raw gas for neutralization). However, the carbon dioxide contained in the purge gas may be entirely derived from the carbon dioxide concentrated gas (for example, the carbon dioxide concentrated gas recovered from the atmosphere by DAC or the carbon dioxide concentrated gas recovered from the biogas by a separation membrane), or only a part of it may be derived from the carbon dioxide concentrated gas. As described above, the carbon dioxide concentrated gas can contain a trace amount of amine compounds, so the mixed gas of the carbon dioxide concentrated gas and the hydrogen can be used as a purge gas without adding an amine compound separately, or only adding a very small amount of amine compound.

[0088] A-6. Modification 2 The separation membrane for separating water vapor and liquid fuel is not limited to a water vapor separation membrane that allows water vapor to pass through, and a liquid fuel separation membrane that allows at least liquid fuel to pass through can be used. It should be noted that in the present invention, as a separation membrane for separating water vapor and liquid fuel, one has a higher selective permeability than the other, and the two do not need to be completely separated as long as the effect of the present invention can be obtained. For example, the liquid fuel separation membrane allows liquid fuel to pass through with a higher selectivity than water vapor, and the two are not completely separated.

[0089] Figure 3 It is a schematic configuration diagram of a liquid fuel production system according to another embodiment of the present invention.

[0090] Figure 3 The liquid fuel production system 1C shown comprises: a liquid fuel synthesis section 10, which carries out a conversion reaction from a raw gas containing at least hydrogen and carbon oxides into a liquid fuel; a raw gas supply section 20, which supplies raw gas to the liquid fuel synthesis section 10; and a raw gas circulation section 30, which supplies the remaining raw gas from the liquid fuel synthesis section 10 to the raw gas supply section 20 again, and the remaining raw gas contains unreacted hydrogen and carbon oxides as well as acidic by-products of the above-mentioned conversion reaction.

[0091] The liquid fuel synthesis unit 10 has a liquid fuel separation membrane 14a that allows liquid fuel to pass through, and separates the permeation side gas and the non-permeation side gas. The permeation side gas is gas that has passed through the liquid fuel separation membrane 14a from the non-permeation side to the permeation side and contains at least liquid fuel, and the non-permeation side gas is gas that has not passed through the liquid fuel separation membrane 14a and contains by-product water vapor, unreacted hydrogen and carbon oxides, and acidic by-products.

[0092] The liquid fuel production system 1C further includes a purge gas supply unit 40 that supplies a gas for purging the permeate-side gas to the permeate side of the liquid fuel synthesizing unit 10 .

[0093] The raw material gas supply unit 20 includes a mixing unit 24 for mixing the amine compound with the remaining raw material gas in the presence of water vapor, and a moisture removal unit 26 for removing a neutralized product of the amine compound and the acidic byproduct together with condensed water of the water vapor.

[0094] According to the liquid fuel production system 1C, by using a gas containing an amine compound (neutralization raw gas) as a purge gas, the purge gas (neutralization raw gas) flowing out of the liquid fuel synthesis unit 10 can be mixed with the non-permeation side gas containing by-product water vapor and the remaining raw gas, and the acidic by-product in the remaining raw gas can be neutralized with the amine compound. The main points of the modification 2 are described below. The other aspects are the same as those described for the liquid fuel production system 1A.

[0095] The liquid fuel synthesis section 10 has a catalyst 12, a liquid fuel separation membrane 14a, a non-permeable side space 10A, and a permeable side space 10B. The liquid fuel separation membrane 14a may also be supported by a porous support 16 as shown in the example. The liquid fuel synthesis section 10 is provided with a first supply port s1 and a first discharge port d1 connected via the non-permeable side space 10A, and a second supply port s2 and a second discharge port d2 connected via the permeable side space 10B. As a separation membrane that selectively allows liquid fuel to pass, for example, a separation membrane described in Japanese Patent Publication No. 2020-23488 can be used.

[0096] The non-permeable side space 10A is a space on the non-permeable side of the liquid fuel separation membrane 14a, and the permeable side space 10B is a space on the permeable side of the liquid fuel separation membrane 14a. The raw gas supplied from the raw gas supply unit 20 flows into the non-permeable side space 10A through the first supply port s1. Liquid fuel is synthesized from the raw gas at the catalyst 12, and the liquid fuel permeates the liquid fuel separation membrane 14a and flows into the permeable side space 10B. The purge gas is supplied to the permeable side space 10B from the purge gas supply unit 40 through the second supply port s2. The permeable side gas and the purge gas flow out of the permeable side space 10B to the raw gas supply unit 20 through the second discharge port d2 as product gas. On the other hand, the remaining raw gas flows out from the non-permeable side space 10A to the raw gas circulation unit 30 through the first discharge port d1 as the non-permeable side gas together with the by-product water vapor.

[0097] The raw gas circulation unit 30 has a non-permeable gas recovery pipe 31. One end of the non-permeable gas recovery pipe 31 is connected to the first outlet d1 of the liquid fuel synthesis unit 10, and the other end is connected to the neutralization raw gas supply pipe 22, so that the non-permeable gas can be supplied to the mixing unit 24.

[0098] The raw gas supply unit 20 includes a raw gas supply pipe 22 for neutralization, a mixing unit 24, a moisture removal unit 26, a pressurizing unit 28, a third condenser 21, a third drain trap 23, and a liquid fuel recovery pipe 25. The product gas recovered from the liquid fuel synthesis unit 10 via the raw gas supply pipe 22 for neutralization is separated into liquid fuel and purge gas by the third condenser 21 and the third drain trap 23, and the liquefied liquid fuel is recovered via the liquid fuel recovery pipe 25. The purge gas is sent to the moisture removal unit 26, and is mixed with the non-permeable side gas (in other words, the remaining raw gas and the by-product water vapor) in the mixing unit 24 upstream of the water removal unit 26. As a result, the acidic by-product contained in the remaining raw gas is neutralized by the amine compound contained in the purge gas. In addition, if the mixed gas of the purge gas and the non-permeable side gas is supplied to the second condenser 26a, the by-product water vapor from the non-permeable side gas is condensed, and the neutralized product generated by the above neutralization is transferred (dissolved) into the condensed water. The condensed water containing the neutralized product is separated from the remaining gas components by the second drain trap 26 b and is recovered (removed) from the water recovery pipe 26 c .

[0099] It should be noted that, according to the liquid fuel separation membrane that does not completely separate the liquid fuel from the water vapor, the permeate side gas can contain the liquid fuel and the by-product water vapor, and therefore the product gas can contain the purge gas containing the amine compound, the liquid fuel, and the water vapor. Therefore, even in the case where the non-permeate side gas does not contain water vapor and the water vapor is separated from the non-permeate side gas, by mixing the product gas after the liquid fuel is separated with the remaining raw gas, the amine compound and the remaining raw gas can be mixed in the presence of water vapor. As described above, in the embodiment using the above-mentioned liquid fuel separation membrane, the water vapor present when the amine compound and the remaining raw gas are mixed can be the water vapor contained in the non-permeate side gas recovered together with the remaining raw gas and / or the water vapor contained in the product gas recovered as the permeate side gas.

[0100] A-7. Modification 3 Figure 4 It is a schematic configuration diagram of a liquid fuel production system according to another embodiment of the present invention.

[0101] Figure 4 The liquid fuel production system 1D shown comprises: a liquid fuel synthesis section 10a, which carries out a conversion reaction from a raw gas containing at least hydrogen and carbon oxides into a liquid fuel; a raw gas supply section 20, which supplies the raw gas to the liquid fuel synthesis section 10a; and a raw gas circulation section 30, which recovers the remaining raw gas from the liquid fuel synthesis section 10a and supplies it to the raw gas supply section 20, wherein the remaining raw gas contains unreacted hydrogen and carbon oxides and acidic by-products of the above-mentioned conversion reaction.

[0102] The liquid fuel production system 1D further includes a temperature control gas supply unit 40 a that supplies a temperature control gas for controlling the temperature of the first gas flow path 10A to the liquid fuel synthesis unit 10 a .

[0103] The raw material gas supply unit 20 includes a mixing unit 24 for mixing the amine compound with the remaining raw material gas in the presence of water vapor, and a moisture removal unit 26 for removing a neutralized product of the amine compound and the acidic byproduct together with condensed water of the water vapor.

[0104] According to the liquid fuel production system 1D, by using a gas containing water vapor and an amine compound (raw gas for neutralization) as a temperature-control gas, the temperature-control gas flowing out of the liquid fuel synthesis section 10a can be mixed with the remaining raw gas, and the acidic by-products in the remaining raw gas can be neutralized with the amine compound and removed together with the condensed water.

[0105] The liquid fuel synthesis section 10a has: a first gas flow path 10A, which is provided with a catalyst 12 for promoting the reforming reaction; and a second gas flow path 10B, through which a temperature-regulating gas for regulating the temperature of the first gas flow path 10A flows. In the illustrated example, the first gas flow path 10A and the second gas flow path 10B are divided into upper and lower parts by a partition wall 18, but the second gas flow path 10B only needs to be configured to be able to regulate the temperature of the first gas flow path 10A. For example, the liquid fuel synthesis section has a double tube structure, and one of the inner tube and the outer tube can be set as the first gas flow path, and the other can be set as the second gas flow path. The partition wall 18 is typically gas-impermeable.

[0106] The raw gas supplied from the raw gas supply unit 20 flows into the first gas flow path 10A through the first supply port s1. Liquid fuel is synthesized from the raw gas at the catalyst 12, and the generated liquid fuel and the remaining raw gas flow out from the first gas flow path 10A to the raw gas circulation unit 30 through the first discharge port d1 as a product gas. The product gas contains liquid fuel, water vapor as a by-product of the conversion reaction, and remaining raw gas. The remaining raw gas contains acidic by-products in addition to unreacted hydrogen and carbon oxides.

[0107] The temperature control gas supplied from the temperature control gas supply unit 40 a flows into the second gas flow path 10B through the second supply port s2 , and flows out from the second discharge port d2 to the raw material gas supply unit 20 .

[0108] The temperature control gas supply unit 40a includes: a temperature control gas storage unit 42 that stores the temperature control gas; a temperature control gas supply pipe 44 that connects the temperature control gas storage unit 42 to the second inlet s2 of the liquid fuel synthesis unit 10a; and a heating unit 46 that is interposed in the temperature control gas supply pipe 44. It should be noted that, in the example shown in the figure, the temperature control gas is supplied to the liquid fuel synthesis unit 10a in a countercurrent manner with the raw material gas, but it may also be supplied in a parallel manner.

[0109] The temperature control gas is heated to a desired temperature (eg, 150° C. to 350° C.) in the heating unit 46 and then supplied to the liquid fuel synthesizing unit 10a from the second inlet s2. The heating unit 46 is not particularly limited as long as it can heat the temperature control gas.

[0110] The temperature control gas contains an amine compound and water vapor, and preferably further contains one or both of hydrogen and carbon oxides. The same description as for the purge gas can be applied to components other than water vapor in the temperature control gas. The water vapor dew point in the temperature control gas is, for example, 40° C. or higher and 150° C. or lower.

[0111] The same description as in Items A-4 and A-5 can be applied to the raw gas supply unit 20 and the raw gas circulation unit 30. Specifically, the raw gas circulation unit 30 includes a product gas recovery pipe 31a, a first condenser 32, a first drain trap 33, a liquid fuel recovery pipe 34, and a raw gas circulation pipe 35. The raw gas supply unit 20 includes a neutralization raw gas supply pipe 22, a mixing unit 24, a moisture removal unit 26, and a pressurizing unit 28.

[0112] The product gas recovered through the product gas recovery pipe 31a contains liquid fuel, by-product water vapor, and residual raw gas containing unreacted hydrogen, carbon oxides, and acidic by-products. The product gas is separated into gas and liquid through the first condenser 32 and the first drain trap 33, and the liquefied liquid fuel and water are recovered through the liquid fuel recovery pipe 34, and the residual raw gas is supplied to the raw gas supply unit 20 (more specifically, the mixing unit 24) through the raw gas circulation pipe 35. The liquid fuel and water recovered from the liquid fuel recovery pipe 34 are further separated and recovered as needed.

[0113] On the other hand, in the raw gas supply section 20, the temperature control gas containing the amine compound and water vapor recovered from the liquid fuel synthesis section 10a via the neutralization raw gas supply piping 22 is mixed with the remaining raw gas upstream of the moisture removal section 26. As a result, the acidic by-products contained in the remaining raw gas are neutralized by the amine compound contained in the temperature control gas, and the neutralized product produced by the neutralization is removed from the moisture removal section 26 together with the condensed water of the water vapor. It should be noted that there is a case where the water vapor generated by the reforming reaction is not completely recovered by the liquid fuel recovery piping 34 due to the difference in boiling point from methanol, and a part of the by-product water vapor can be supplied to the mixing section 24 via the raw gas circulation piping 35. Therefore, even when the temperature control gas does not contain water vapor, the amine compound and the acidic by-product can be neutralized in the presence of the by-product water vapor supplied via the raw gas circulation piping 35.

[0114] The gas component after the condensed water and the neutralized product are separated is pressurized and heated in the pressurizing unit 28 and then supplied as a raw gas to the first gas flow path 10A of the liquid fuel synthesizing unit 10 a .

[0115] A-8. Modification 4 The amine compound used to neutralize the above-mentioned acidic by-products can be ammonia generated from the above-mentioned hydrogen and nitrogen in the liquid fuel synthesis section when using a raw gas containing nitrogen in addition to hydrogen and carbon oxides. Ammonia has a small molecular diameter and is easier to permeate the separation membrane than other gases. Therefore, for example, in the case where the liquid fuel synthesis section has a water vapor separation membrane, the ammonia generated in the non-permeable side space of the liquid fuel synthesis section can pass through the water vapor separation membrane as a permeable side gas together with water vapor, be purged by the purge gas, and flow out from the liquid fuel synthesis section (more specifically, from the discharge port d2 of the permeable side space) as an exhaust gas. Therefore, the exhaust gas (mixed gas of the permeable side gas and the purge gas) contains water vapor and ammonia. By supplying such an exhaust gas to the mixing section and mixing it with the remaining raw gas, the acidic by-products in the remaining raw gas can be neutralized using the ammonia contained in the permeable side gas in the presence of water vapor. In addition, for example, in the case where the liquid fuel synthesis section has a liquid fuel separation membrane, ammonia generated in the non-permeable side space of the liquid fuel synthesis section can pass through the liquid fuel separation membrane as a permeable side gas together with the liquid fuel, be purged by the purge gas, and flow out from the liquid fuel synthesis section (more specifically, from the discharge port d2 of the permeable side space) as a product gas. Therefore, the product gas (mixed gas of the permeable side gas and the purge gas) contains liquid fuel and ammonia. In addition, the non-permeable side gas flowing out from the discharge port d1 of the non-permeable side space of the liquid fuel synthesis section contains water vapor and residual raw material gas. Therefore, after separating the liquid fuel from the product gas, the non-permeable side gas is supplied to the mixing section and mixed with the non-permeable side gas, and the acidic by-product in the residual raw material gas can be neutralized using the ammonia contained in the permeable side gas in the presence of water vapor. In addition, according to the liquid fuel separation membrane that does not completely separate the liquid fuel from the water vapor, the ammonia generated in the non-permeable side space of the liquid fuel synthesis section can pass through the liquid fuel separation membrane as a permeable side gas together with the liquid fuel and the water vapor, be purged by the purge gas, and flow out from the liquid fuel synthesis section as a product gas. Therefore, even when the non-permeable side gas does not contain water vapor or when water vapor is separated from the non-permeable side gas, by supplying the product gas after separation of the liquid fuel and the remaining raw gas to the mixing section for mixing, the acidic by-products in the remaining raw gas can be neutralized using ammonia contained in the permeable side gas in the presence of water vapor.

[0116] The ammonia concentration in the exhaust gas or product gas is, for example, 10 ppm or more, and for example, less than 10000 ppm. The ammonia concentration is the concentration at the outlet d2 of the liquid fuel synthesis unit, and is calculated by removing condensable components from the exhaust gas or product gas.

[0117] In addition, the liquid fuel production system of Modification 4 may also be configured to include the carbon dioxide recovery unit described in Modification 1, and to prepare the raw gas using the carbon dioxide-containing gas recovered from the atmosphere or biogas by the carbon dioxide recovery unit. The carbon dioxide-containing gas recovered from the atmosphere or biogas may contain a small amount of nitrogen in addition to carbon dioxide, so the raw gas may be prepared without adding nitrogen, or by adding only a small amount of nitrogen.

[0118] B. Methods for producing liquid fuel The method for producing a liquid fuel according to an embodiment of the present invention includes the following steps: The raw material gas is supplied to a liquid fuel synthesis unit including a catalyst, wherein the catalyst causes a conversion reaction from the raw material gas containing at least hydrogen and carbon oxides to a liquid fuel (step I); Not only advancing the above-mentioned conversion reaction, but also recovering a residual raw gas from the above-mentioned liquid fuel synthesis section, the residual raw gas containing the above-mentioned unreacted hydrogen and the above-mentioned carbon oxides and acidic by-products (step II); removing the acidic by-product from the remaining raw gas (step III); and The remaining raw material gas after the acidic by-products are removed is supplied to the liquid fuel synthesis section again as a part of the raw material gas (step IV).

[0119] Typically, the acidic byproducts are removed from the excess raw gas by the following method: an amine compound and the excess raw gas are mixed in the presence of water vapor, and the acidic byproducts in the excess raw gas are neutralized with the amine compound. The neutralized product generated by the neutralization is removed together with the condensed water of the water vapor. Preferably, the gas after the condensed water and the neutralized product are removed from the mixed gas is supplied to the liquid fuel synthesis unit as a constituent component of the raw gas.

[0120] In a method for producing liquid fuel in which unreacted raw gas is recovered and circulated and reused as raw gas, the concentration of acidic byproducts in the raw gas gradually increases with the number of cycles, which may result in a decrease in the yield of liquid fuel and corrosion of the liquid fuel production system. In contrast, according to a method for producing liquid fuel based on an embodiment of the present invention, by mixing an amine compound with the remaining raw gas, the acidic byproducts can be neutralized and removed with the amine compound, and by using the removed mixed gas as a constituent component of the raw gas, the problem of concentration of the acidic byproducts can be prevented.

[0121] The method for producing liquid fuel according to the embodiment of the present invention can be appropriately performed using the liquid fuel production system described in item A. Hereinafter, an embodiment of a liquid fuel production system 1A using a liquid fuel synthesis section including a water vapor separation membrane and using a purge gas containing an amine compound as a raw material gas for neutralization will be described. Of course, the method for producing liquid fuel according to the embodiment of the present invention can also be performed according to the description in item A in the case of using a liquid fuel production system including a liquid fuel synthesis section including a liquid fuel separation membrane, a liquid fuel production system including a separation membrane and using a raw material gas containing nitrogen in addition to carbon oxides and hydrogen, etc. In addition, when a liquid fuel production system 1D is used and a temperature-controlled gas after flowing through the liquid fuel synthesis section is used as a raw material gas for neutralization in order to adjust the reaction temperature of the conversion reaction, the method for producing liquid fuel according to the embodiment of the present invention can also be performed in the same manner as when the liquid fuel production system 1A is used. For example, a temperature-controlled gas containing an amine compound and water vapor can be circulated in the liquid fuel synthesis section, and the temperature-controlled gas after flowing through the liquid fuel synthesis section can be used to neutralize and remove acidic byproducts.

[0122] B-1. Process I In step I, a raw gas is supplied to a liquid fuel synthesis unit, which includes: a catalyst for promoting a conversion reaction from a raw gas containing at least hydrogen and carbon oxides to a liquid fuel; and a water vapor separation membrane for allowing water vapor to pass. As described in item A, the liquid fuel synthesis unit 10 includes a catalyst 12, a water vapor separation membrane 14, a non-permeable side space 10A, and a permeable side space 10B. The raw gas is supplied to the non-permeable side space 10A of the liquid fuel synthesis unit 10 from the first inlet s1.

[0123] As described above, the raw gas contains at least hydrogen and carbon oxides. The concentrations of hydrogen and carbon oxides in the raw gas are as described above. The concentration of the acidic byproducts in the raw gas (the total concentration when there are two or more acidic byproducts) is preferably as small as possible, for example, 30 ppm or less, preferably 20 ppm or less.

[0124] B-2. Process II In step II, not only the above-mentioned conversion reaction is advanced, but also the remaining raw material gas containing unreacted hydrogen and carbon oxides and acidic by-products is recovered from the liquid fuel synthesis section.

[0125] The reforming reaction proceeds in the catalyst 12, thereby generating liquid fuel and water vapor. Specifically, as shown in the above reaction formula (2), the CO 2The raw material gas containing hydrogen and methanol is catalytically hydrogenated in the presence of a catalyst, thereby generating methanol and water vapor. In addition, at this time, a trace amount of acidic components (acidic by-products) are generated as by-products other than water vapor. The reaction conditions are as described in item A.

[0126] The liquid fuel generated in the non-permeable side space 10A flows out to the non-permeable side gas recovery pipe 31 through the first outlet d1 together with the remaining raw gas containing unreacted hydrogen and carbon oxides and acidic byproducts, and is separated from the remaining raw gas by gas-liquid separation in the first condenser 32 and the first liquid drain 33. Thus, the liquid fuel is recovered from the liquid fuel recovery pipe 34, and the remaining raw gas is recovered from the raw gas circulation pipe 35.

[0127] B-3. ​​Step III In step III, acidic by-products are removed from the above-mentioned remaining raw material gas.

[0128] The liquid fuel production system 1A is configured to prepare the raw gas by mixing the purge gas separately recovered from the liquid fuel synthesis unit 10 with the remaining raw gas, so by using the purge gas containing the amine compound, the acidic byproduct contained in the remaining raw gas can be removed by neutralization with the amine compound. Specifically, as described below.

[0129] In the liquid fuel production system 1A, water vapor generated in the non-permeable side space 10A and part of the hydrogen in the raw gas pass through the water vapor separation membrane 14 and flow into the permeable side space 10B. The purge gas containing an amine compound and any hydrogen and / or carbon oxide flows into the permeable side space 10B from the second inlet s2. The water vapor and hydrogen flowing into the permeable side space 10B are purged by the purge gas and flow out as exhaust gas to the neutralization raw gas supply pipe (exhaust gas recovery pipe) 22 through the second outlet d2. The exhaust gas is mixed with the remaining raw gas through the raw gas circulation pipe 35 and merged with the neutralization raw gas supply pipe 22 in the mixing section 24. As a result, the acidic by-products derived from the remaining raw gas are neutralized by the amine compound derived from the purge gas contained in the exhaust gas. The mixed gas of the exhaust gas and the remaining raw gas passes through the second condenser 26a and the second drain trap 26b in sequence, during which the water vapor is condensed and separated into gas and liquid, and is recovered (removed) from the water recovery pipe 26c. Preferably, the neutralized product generated by the neutralization is dissolved in the condensed water and removed from the water recovery pipe 26c together with the condensed water.

[0130] B-4. Step IV In step IV, the remaining raw gas after the acidic byproducts are removed is supplied to the liquid fuel synthesis unit as a part of the raw gas. Specifically, the mixed gas after the water content is removed in step III is used as the raw gas, and after the pressure booster 28 is adjusted to the desired temperature and pressure, it is supplied to the liquid fuel synthesis unit 10. As described above, hydrogen and / or carbon oxides can be mixed with the mixed gas after the water content is removed in step III as needed to prepare the raw gas into a desired composition.

[0131] Industrial Applicability The liquid fuel production system according to the embodiment of the present invention can be applied to the production of liquid fuels such as methanol.

[0132] Description of Reference Numerals 1A-D Liquid Fuel Manufacturing System 10 Liquid Fuel Synthesis Department 20 Raw material gas supply unit 30 Raw gas circulation unit 40 Purge gas supply.

Claims

1. A liquid fuel production system, characterized in that: The liquid fuel production system comprises: A liquid fuel synthesis section that performs a conversion reaction from a raw gas containing at least hydrogen and carbon oxides into a liquid fuel; a raw gas supply unit that supplies the raw gas to the liquid fuel synthesis unit; and a raw gas circulation section that resupplies the remaining raw gas from the liquid fuel synthesis section to the raw gas supply section, wherein the remaining raw gas contains the unreacted hydrogen and carbon oxides and the acidic by-products of the conversion reaction, The raw material gas supply unit comprises: a mixing section that mixes the amine compound with the remaining raw material gas in the presence of water vapor; as well as A moisture removal unit removes a neutralized product of the amine compound and the acidic byproduct together with condensed water of the water vapor.

2. The liquid fuel production system according to claim 1, wherein: In the mixing section, the neutralization raw material gas containing the amine compound is mixed with the remaining raw material gas.

3. The liquid fuel production system according to claim 1, wherein: The raw material gas also contains nitrogen, The amine compound is ammonia generated from the hydrogen gas and the nitrogen gas in the liquid fuel synthesis section.

4. The liquid fuel production system according to claim 2, wherein: The liquid fuel production system further comprises a gas recovery unit for recovering carbon dioxide from the atmosphere or biogas. The carbon dioxide-containing gas supplied from the gas recovery unit is used as a constituent component of the neutralization raw material gas.

5. The liquid fuel production system according to claim 2, wherein: The liquid fuel synthesis section has a water vapor separation membrane that allows at least water vapor to pass through, and separates a permeation side gas from a non-permeation side gas, wherein the permeation side gas is gas that has passed through the water vapor separation membrane from the non-permeation side to the permeation side and contains water vapor as a by-product of the reforming reaction, and the non-permeation side gas is gas that has not passed through the water vapor separation membrane and contains the liquid fuel, the unreacted hydrogen and carbon oxides, and the acidic by-products. The liquid fuel production system further includes a purge gas supply unit configured to supply a purge gas containing an amine compound to purge the permeate side gas to the permeate side of the liquid fuel synthesis unit. The permeated-side gas and the purge gas flowing out of the liquid fuel synthesizing section are supplied to the mixing section.

6. The liquid fuel production system according to claim 5, wherein: The purge gas may also contain carbon oxides and / or hydrogen.

7. The liquid fuel production system according to claim 5, wherein: The concentration of the amine compound in the purge gas is 10 ppm or more.

8. The liquid fuel production system according to claim 3, wherein: The liquid fuel synthesis section has a water vapor separation membrane that allows at least water vapor and ammonia to pass through, and separates a permeation side gas from a non-permeation side gas, wherein the permeation side gas is gas that has passed through the water vapor separation membrane from the non-permeation side to the permeation side and contains water vapor and ammonia as by-products of the reforming reaction, and the non-permeation side gas is gas that has not passed through the water vapor separation membrane and contains the liquid fuel, unreacted hydrogen and carbon oxides, and the acidic by-products. The liquid fuel production system further includes a purge gas supply unit configured to supply a purge gas for purging the permeate-side gas to the permeate-side of the liquid fuel synthesis unit. The permeated-side gas and the purge gas flowing out of the liquid fuel synthesizing section are supplied to the mixing section.

9. The liquid fuel production system according to claim 8, wherein: The ammonia concentration in the mixed gas of the permeate-side gas and the purge gas is 10 ppm or more.

10. The liquid fuel production system according to claim 2, wherein: The liquid fuel synthesis section has a liquid fuel separation membrane that allows at least liquid fuel to permeate, and separates a permeation side gas from a non-permeation side gas, wherein the permeation side gas is gas that has permeated the liquid fuel separation membrane from the non-permeation side to the permeation side and contains the liquid fuel, and the non-permeation side gas is gas that has not permeated the liquid fuel separation membrane and contains water vapor as a by-product of the conversion reaction, unreacted hydrogen and carbon oxides, and the acidic by-products. The liquid fuel production system further includes a purge gas supply unit configured to supply a purge gas containing an amine compound to purge the permeate side gas to the permeate side of the liquid fuel synthesis unit. The purge gas flowing out from the liquid fuel synthesizing section is supplied to the mixing section.

11. The liquid fuel production system according to claim 10, wherein: The purge gas may also contain carbon oxides and / or hydrogen.

12. The liquid fuel production system according to claim 10, wherein: The concentration of the amine compound in the purge gas is 10 ppm or more.

13. The liquid fuel production system according to claim 3, wherein: The liquid fuel synthesis section has a liquid fuel separation membrane that allows at least liquid fuel and ammonia to permeate, and separates a permeation side gas from a non-permeation side gas, wherein the permeation side gas is gas that has permeated the liquid fuel separation membrane from the non-permeation side to the permeation side and contains the liquid fuel and the ammonia, and the non-permeation side gas is gas that has not permeated the liquid fuel separation membrane and contains water vapor as a by-product of the conversion reaction, unreacted hydrogen and carbon oxides, and the acidic by-products. The liquid fuel production system further includes a purge gas supply unit configured to supply a purge gas for purging the permeate-side gas to the permeate-side of the liquid fuel synthesis unit. The permeated-side gas and the purge gas flowing out of the liquid fuel synthesizing section are supplied to the mixing section.

14. The liquid fuel production system according to claim 13, wherein: The ammonia concentration in the mixed gas of the permeate-side gas and the purge gas is 10 ppm or more.

15. The liquid fuel production system according to claim 2, wherein: The liquid fuel synthesis unit comprises: a first gas flow path in which a catalyst for promoting the reforming reaction is arranged; and a second gas flow path in which a temperature-adjusting gas for adjusting the temperature of the first gas flow path flows. The liquid fuel production system further includes a temperature control gas supply unit configured to supply a temperature control gas containing an amine compound to the second gas flow path of the liquid fuel synthesis unit. The temperature-adjusting gas flowing out of the liquid fuel synthesizing unit is supplied to the mixing unit.

16. The liquid fuel production system according to claim 15, wherein: The temperature control gas may also contain carbon oxides and / or hydrogen.

17. The liquid fuel production system according to claim 15, wherein: The concentration of the amine compound in the temperature control gas is 10 ppm or more.

18. A method for producing a liquid fuel, characterized in that: The method for producing the liquid fuel comprises the following steps: supplying a raw gas to a liquid fuel synthesis section including a catalyst, wherein the catalyst promotes a conversion reaction of the raw gas containing at least hydrogen and carbon oxides into a liquid fuel; Not only advancing the conversion reaction, but also recovering a residual raw gas from the liquid fuel synthesis unit, wherein the residual raw gas contains the unreacted hydrogen and the carbon oxides and acidic by-products; removing the acidic byproduct from the remaining feed gas; as well as supplying the remaining raw gas after removing the acidic by-products to the liquid fuel synthesis unit as a part of the raw gas, The step of removing the acidic by-products from the remaining raw gas includes the steps of mixing an amine compound with the remaining raw gas in the presence of water vapor and neutralizing the acidic by-products with the amine compound.

19. The manufacturing method according to claim 18, wherein: The step of removing the acidic by-product from the excess raw gas includes the step of mixing the neutralization raw gas containing the amine compound supplied to the liquid fuel synthesis section and flowing through the liquid fuel synthesis section with the excess raw gas.

20. The manufacturing method according to claim 18, wherein: The raw material gas also contains nitrogen, The amine compound is ammonia generated from the hydrogen gas and the nitrogen gas in the liquid fuel synthesis section.

21. The manufacturing method according to claim 19, wherein: The neutralization raw material gas is prepared using a gas containing carbon dioxide recovered from the atmosphere or biogas.

22. The manufacturing method according to claim 19, wherein: The liquid fuel synthesis unit includes a water vapor separation membrane that allows at least water vapor to pass through. allowing water vapor as a by-product of the conversion reaction to pass from the non-permeable side to the permeable side of the water vapor separation membrane, and purging with a purge gas containing the amine compound, and recovering it as an exhaust gas from the liquid fuel synthesis section, The exhaust gas is mixed with the remaining raw gas, and the acidic by-product in the remaining raw gas is neutralized with the amine compound.

23. The manufacturing method according to claim 19, wherein: The liquid fuel synthesis unit includes a liquid fuel separation membrane that allows at least liquid fuel to permeate. The liquid fuel is allowed to permeate from the non-permeation side to the permeation side of the liquid fuel separation membrane, and is purged with a purge gas containing the amine compound, and recovered as a product gas from the liquid fuel synthesis section, and water vapor as a by-product of the conversion reaction is recovered, separating the product gas into the liquid fuel and the purge gas, The purge gas, the remaining raw material gas, and the water vapor are mixed, and the acidic by-product in the remaining raw material gas is neutralized with the amine compound.

24. The manufacturing method according to claim 19, wherein: A temperature control gas containing the amine compound for adjusting the reaction temperature of the conversion reaction is passed through the liquid fuel synthesis section. The temperature-adjusted gas flowing through the liquid fuel synthesizing section is mixed with the remaining raw material gas, and the acidic by-product in the remaining raw material gas is neutralized with the amine compound.

25. The manufacturing method according to claim 20, wherein: The liquid fuel synthesis unit includes a water vapor separation membrane that allows at least water vapor and ammonia to pass through. The water vapor and the ammonia as byproducts of the conversion reaction are allowed to pass from the non-permeable side to the permeable side of the water vapor separation membrane, and are purged with a purge gas and recovered as exhaust gas from the liquid fuel synthesis section, The exhaust gas is mixed with the remaining raw gas, and the acidic byproducts in the remaining raw gas are neutralized with the ammonia.

26. The manufacturing method according to claim 20, wherein: The liquid fuel synthesis unit includes a liquid fuel separation membrane that allows at least liquid fuel and ammonia to permeate. The liquid fuel and the ammonia are made to permeate from the non-permeation side to the permeation side of the liquid fuel separation membrane, and are purged with a purge gas to be recovered as a product gas from the liquid fuel synthesis section, and water vapor as a by-product of the conversion reaction is recovered together with the remaining raw gas, The liquid fuel is separated from the product gas and then mixed with the remaining raw gas and the water vapor, and the acidic by-products in the remaining raw gas are neutralized with the ammonia.

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