Method for producing bioethanol and apparatus for producing bioethanol

Abstract

This method for producing bioethanol involves: a carbonization step for carbonizing biomass to generate a carbonized material; a reforming gasification step for performing a mixed gasification reaction of the carbonized material with water vapor and carbon dioxide to generate a reforming gas containing hydrogen, carbon monoxide, methane, and carbon dioxide; an ethanol production step for bringing the reforming gas into contact with a C2-oxygenated catalyst and a hydrogenation catalyst to produce ethanol; and a mixing step for separating and recovering a metal-containing residue generated together with the reforming gas in the reforming gasification step from the reforming gas, and mixing the metal-containing residue with the biomass.

Description

Bioethanol production method and bioethanol production equipment

[0001] The present invention relates to a method for producing bioethanol and an apparatus for producing bioethanol. This application claims priority to Japanese Patent Application No. 2024-048238, filed on March 25, 2024, the contents of which are incorporated herein by reference.

[0002] Generally, biomass refers to biologically derived materials that can be used as an energy source or industrial raw material. Biomass includes, for example, organic waste such as thinned wood, agricultural products, food products made from them, processed products such as cotton cloth, clothing fibers, and furniture, construction waste, and household garbage. Biomass is a neutral carbon material that can be infinitely renewable because it is produced cyclically through the actions of solar energy, air, water, carbon dioxide, soil, and the like.

[0003] Fermentation methods, bioethanol production technologies, and bioethanol production systems using food biomass such as rice, corn, sugarcane, and taro as raw materials have been developed. Meanwhile, bioethanol production methods that utilize non-food biomass materials such as thinnings and agricultural and industrial waste are useful as technologies for reducing the volume of agricultural and industrial waste and recycling it. Currently, there is a need to develop bioethanol production technologies that can expand the range of raw material options.

[0004] Traditionally, hydrothermal decomposition of biomass has been known as a method for converting non-food biomass into bioethanol. In this method, sugar components are extracted in the presence of acid or alkali, and the resulting sugar components are then fermented to produce bioethanol. However, the hydrothermal decomposition of biomass poses technical and economic problems related to bioethanol production, such as low bioethanol yield and high production costs.

[0005] Meanwhile, technologies for gasifying biomass have been proposed. One reported example of a biomass gasification technology is a technology in which air and steam are used in a fixed-bed or fluidized-bed gasification furnace or the like to directly gasify biomass through a thermochemical gasification reaction. Another reported example of a biomass gasification technology is a technology in which char obtained by a pyrolysis reaction of biomass is gasified with steam. Known methods for utilizing the gas produced by biomass gasification technology (hereinafter sometimes referred to as "biomass gas" or "reformed gas") include gas engine power generation, hydrogen production, production of alcohols such as methanol and ethanol, and Fischer-Tropsch (FT) hydrocarbon fuel production (see Patent Documents 1 to 4 and Non-Patent Documents 1 to 3).

[0006] Japanese Patent Publication No. 2008-88434 Japanese Patent No. 5342664 International Publication No. 2020 / 166659 International Publication No. 2010 / 092819

[0007] Kenichi Sasauchi, "Power Generation by Pyrolysis Gasification of Biomass," Journal of the Combustion Society of Japan, Vol. 47, No. 139 (2005), pp. 31-39; Masaru Ichikawa, editor, "New Developments in Biomass Refinery Catalyst Technology," CMC Publishing (2011), pp. 70-89; Masaru Ichikawa, "New Developments in Hydrogen Energy Technology Utilizing Biomass Resources," Life and Environment, Vol. 61, No. 1 (2016)

[0008] However, conventional biomass pyrolysis carbonization technologies have had the problem that the carbonization of biomass does not proceed efficiently or uniformly, resulting in a low carbonization rate of the carbonized product and a low yield of reformed gas during gasification of the carbonized product.In addition, there are issues with the inability to efficiently and stably obtain bioethanol in the bioethanol production process using the reformed gas.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a bioethanol production method and a bioethanol production apparatus that can improve the carbonization rate of the carbonized material obtained in a carbonization process using biomass, improve the yield of reformed gas produced by gasifying the carbonized material, and efficiently and stably produce bioethanol.

[0010] The present invention has the following aspects: [1] a carbonization step of carbonizing biomass to produce a carbonized product; a reformed-gasification step of carrying out a mixed gasification reaction of the carbonized product with steam and carbon dioxide to produce a reformed gas containing hydrogen, carbon monoxide, methane, and carbon dioxide; ２ A method for producing bioethanol, comprising: an ethanol production step of producing ethanol by contacting a biomass with an oxygenated catalyst and a hydrogenation catalyst; and a mixing step of separating and recovering a metal-containing residue generated together with the reformed gas in the reformed-gasification step from the reformed gas and mixing the metal-containing residue with the biomass. [2] The method for producing bioethanol according to [1], wherein the metal-containing residue contains at least one element selected from the group consisting of alkali metals, alkaline earth metals, metalloids, aluminum, iron, and nickel. [3] The method for producing bioethanol according to [1] or [2], comprising a shift reaction step of producing hydrogen and carbon dioxide by shift reaction of carbon monoxide and methane contained in the residual gas after separation of a liquid product containing ethanol from the gas produced in the ethanol production step with water vapor. [4] The method for producing bioethanol according to [3], comprising a supply step of separating and recovering carbon dioxide from a mixed gas of hydrogen and carbon dioxide generated in the shift reaction step, supplying the recovered carbon dioxide to the reformed-gasification step, and supplying the hydrogen to the reformed gas. [5] The method for producing bioethanol according to [3] or [4], wherein the shift reaction step uses a shift reaction catalyst containing at least one element selected from the group consisting of iron, ruthenium, nickel, copper, zinc, potassium, lithium, magnesium, chromium, cobalt, molybdenum, zirconia, titanium, cerium, lanthanum, and neodymium, and a porous oxide support. [6] The method for producing bioethanol according to any of [1] to [5], wherein the dry distillation gas generated together with the carbonized material in the carbonization step is combusted with air, and the generated combustion gas is used as a heat source to heat at least one of the carbonization step, the reformed-gasification step, the ethanol production step, and the shift reaction step. [7] The method for producing bioethanol according to any of [1] to [5], wherein the C ２The method for producing bioethanol according to any one of [1] to [6], wherein the oxygenated catalyst comprises Rh, at least one element selected from the group consisting of Mn, Sc, Li, Na, K, Cs, Mg, Ba, Pt, Pd, Ir, Mo, W, V, Zr, Hf, Ti, Y, Ce, and La, and a porous carrier. [8] The method for producing bioethanol according to any one of [1] to [7], wherein the hydrogenation catalyst comprises at least one element selected from the group consisting of palladium, iron, nickel, platinum, copper, chromium, zinc, potassium, sodium, cerium, and titanium, and a porous carrier. [9] The method for producing bioethanol according to any one of [1] to [7], wherein in the ethanol production step, the C ２ A composite catalyst prepared by mixing an oxygen-containing catalyst and the hydrogenation catalyst is used, and the C relative to the hydrogenation catalyst in the composite catalyst is ２ The volume ratio of the oxygenated catalyst (C ２

[10] A method for producing bioethanol according to any one of [1] to [8], wherein the ratio of oxygenated catalyst to hydrogenated catalyst) is 0.1 or more and 5 or less.

[10] A method for producing bioethanol according to any one of [1] to [8], wherein the ratio of oxygenated catalyst to hydrogenated catalyst) is 0.1 or more and 5 or less.

[10] A method for producing bioethanol according to any one of [1] to [8], comprising: a reforming gasification furnace; a biomass supply facility; a biomass supply amount adjustment means; a biomass dryer having a means for adjusting and controlling the dryness of the biomass; a carbonization furnace having a temperature rise adjustment means; a carbonized material supply facility for supplying carbonized material to the reforming gasification furnace; a carbonized material supply amount adjustment means for adjusting the amount of carbonized material supplied to the reforming gasification furnace; a supply facility for supplying steam and carbon dioxide to the reforming gasification furnace; a carbon dioxide supply amount adjustment means for adjusting the amount of the steam and the carbon dioxide supplied to the reforming gasification furnace; a reformed gas supply facility for supplying reformed gas to the reforming gasification furnace; ２ an ethanol production facility for producing bioethanol by contacting the reformed gas with an oxygenation catalyst and a hydrogenation catalyst; a separation and recovery means for separating and recovering a metal-containing residue generated together with the reformed gas from the reformed gas; a metal residue supplying facility for supplying the recovered metal-containing residue to the biomass and mixing it with the biomass; a metal-containing residue supply amount adjusting means for adjusting the amount of the metal-containing residue to be supplied to the biomass; ２ a catalyst mixing and preparation facility for mixing and preparing an oxygenated catalyst and the hydrogenation catalyst; ２A bioethanol production apparatus comprising: a catalyst mixing amount adjusting means for adjusting the mixing amount of an oxygenated catalyst.

[11] A gas separation facility that separates carbon dioxide from a mixed gas of hydrogen and carbon dioxide contained in the residual gas after separating the reaction gas generated in the bioethanol production facility from a liquid product containing ethanol; a first piping facility that supplies the carbon dioxide recovered in the gas separation facility to the reforming-gasification furnace; a carbon dioxide supply amount adjustment means that adjusts the amount of the recovered carbon dioxide supplied to the reforming-gasification furnace; a second piping facility that supplies residual hydrogen remaining in the gas separation facility to a hydrogen holder; a hydrogen supply amount adjustment means that adjusts the amount of the residual hydrogen supplied to the hydrogen holder; a third piping facility that supplies hydrogen generated in a water electrolysis facility to the hydrogen holder; a supply facility that supplies the residual hydrogen and the hydrogen from the hydrogen holder to the reforming-gasification furnace; a hydrogen supply amount adjustment means that adjusts the amount of the residual hydrogen and the hydrogen supplied to the reforming-gasification furnace; a pressurization and circulation supply facility that brings the reformed gas into contact with a composite catalyst; and a reformed gas circulation amount adjustment means that adjusts the amount of the reformed gas circulated to the composite catalyst. and a separation and purification facility for separating and purifying bioethanol from a liquid product containing ethanol.

[12] The bioethanol production apparatus according to

[10] or

[11] , comprising: a combustion furnace that combusts the dry distillation gas generated in the carbonization furnace; a heat exchanger that heats steam to be introduced into the reforming-gasification furnace; piping equipment that supplies the combustion gas generated in the combustion furnace as a heating gas to at least one of the reforming-gasification furnace, the biomass dryer, the carbonization furnace, and a shift reaction facility; gas temperature adjustment means that adjusts the temperature of the gas; and gas flow rate adjustment means that adjusts the flow rate of the gas.

[0011] According to the present invention, it is possible to provide a bioethanol production method and a bioethanol production apparatus that can economically and stably produce reformed gas using biomass and subsequently efficiently and stably produce bioethanol.

[0012] 1 is a schematic diagram of a bioethanol production apparatus for carrying out a bioethanol production method according to one embodiment of the present invention.

[0013] As used herein, "bioethanol" refers to ethanol produced using biomass as a raw material. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after the range are included as the lower and upper limits.

[0014] 1 is a schematic diagram of a bioethanol production apparatus for carrying out a bioethanol production method according to one embodiment of the present invention. The bioethanol production apparatus 100 of this embodiment includes a biomass dryer 12, a carbonization furnace 20, a reforming-gasification furnace 30, a metal-containing residue supply facility 37, an ethanol production facility 50, a catalyst mixer / preparator (catalyst mixer / preparator) 57, a biomass supply rate regulator (biomass supply rate regulator) 80, a charcoal supply rate regulator (charcoal supply rate regulator) 81, a carbon dioxide supply rate regulator (carbon dioxide supply rate regulator) 83, a reformed gas supply rate regulator (reformed gas supply facility) 86, a biomass supply facility 91, a charcoal supply facility 92, a supply facility 93, a metal-containing residue separation / recovery facility (metal-containing residue separation / recovery means) 94, and a catalyst mixer / preparator (catalyst mixer / preparator) 95.

[0015] The biomass receiver 11 is disposed in front of the carbonization furnace 20 and receives the biomass 1 from the outside.

[0016] The biomass dryer 12 has a means for adjusting and controlling the dryness of the biomass 1. A rotary kiln dryer can be used as the biomass dryer 12. The rotary kiln dryer dries the biomass 1 in the biomass receiver 11 and feeds it into the carbonization furnace 20. The supply of the biomass 1 to the carbonization furnace 20 may be continuous or intermittent.

[0017] The carbonization furnace 20 carbonizes the biomass 1 through a pyrolysis carbonization operation. The carbonization furnace 20 has a temperature rise adjustment means for adjusting the temperature rise when carbonizing the biomass 1. In carbonization through pyrolysis carbonization, the biomass 1 is heated in a low-oxygen or oxygen-free state to cause pyrolysis. The pyrolysis of the biomass 1 produces a char 2. In addition to the char, dry distillation gases 5 such as decomposition gas and tar are also produced. The carbonization furnace 20 may be equipped with a stirring means for stirring the biomass 1. The stirring means may be a known type, such as a turntable type or a moving scree type.

[0018] The reforming gasification furnace 30 gasifies the carbonized material 2. Specifically, the reforming gasification furnace 30 converts the carbonized material 2 into a reformed gas 8 (H ２ , CO, CH ４ and CO ２ The reforming gasification furnace 30 includes an inner cylinder 30a and an outer cylinder 30b surrounding the inner cylinder 30a. The inner cylinder 30a accommodates the carbide 2. The inner cylinder 30a is heated by supplying a heating gas to the gap between the inner cylinder 30a and the outer cylinder 30b, and the carbide, water vapor, and CO are heated by the heat from the inner cylinder 30a. ２ is heated, and reformed gasification proceeds.

[0019] A first steam supply pipe 33 for supplying steam is connected to the reforming gasification furnace 30 via a steam supply amount regulator 84. A carbon dioxide supply pipe 32 is also connected to the reforming gasification furnace 30 via a carbon dioxide supply amount regulator 83. A dust collector 34 for separating and recovering metal-containing residue 3 from the reformed gas 8 discharged from the reforming gasification furnace 30 is connected to the reforming gasification furnace 30 via a first reformed gas pipe 35.

[0020] The dust collector 34 is connected to a gas purifier 36 that removes sulfur-containing and chlorine-containing components from the reformed gas 8 from which the metal-containing residue 3 has been separated and removed in the dust collector 34 .

[0021] The metal residue supplying equipment 37 supplies and mixes the metal-containing residue recovered in the metal-containing residue separation and recovery device 94 with the biomass 1. The supply of the metal-containing residue to the biomass 1 may be continuous or intermittent. Here, the ratio of the supply rate (kg / h) of the metal-containing residue to the supply rate (kg / h) of the biomass 1 (metal-containing residue supply rate / biomass supply rate) is preferably 0.01 or more and 10 or less, more preferably 0.05 or more and 5 or less, and even more preferably 0.1 or more and 1 or less. When the ratio is equal to or greater than the lower limit, the carbonization rate of the char and the reformed gasification rate increase. When the ratio is equal to or less than the upper limit, the mixing efficiency and mixing uniformity of the biomass and the metal-containing residue are improved. The metal-containing residue receiver 38 receives the metal-containing residue recovered in the metal-containing residue separation and recovery device 94.

[0022] The ethanol production facility 50 converts the reformed gas into C ２ The ethanol production facility 50 is configured to produce bioethanol by contacting the ethanol with a composite catalyst 63, which is a mixture of an oxygenation catalyst 58 and a hydrogenation catalyst 59. ２ The biomass gas is treated with an oxygenation catalyst and a hydrogenation catalyst. ２ When contacted with an oxygen-containing catalyst, the H contained in the biomass gas ２ , CO, CO ２ , C.H. ４ From C such as acetic acid, acetaldehyde, and ethanol ２ Oxygen-containing compounds are produced. ２ In some cases, derivatives of oxygen-containing compounds are produced. Furthermore, when a hydrogenation catalyst is contacted, ethanol is produced from acetic acid, acetaldehyde, methyl acetate, ethyl acetate, etc., and the ethanol selectivity is increased. In this embodiment, the biomass gas supplied to the ethanol production facility 50 contains CO, H ２ , C.H. ４ and CO ２ Contains. CH ４ and CO ２ By including ４ and CO ２ The yield of ethanol is improved compared to when it is not contained.

[0023] C ２ The oxygen-containing catalyst is a catalyst that efficiently converts the C ２ It is a catalyst for producing oxygen-containing compounds. ２ The oxygen-containing catalyst contains Rh, at least one element selected from the group consisting of Mn, Sc, Li, Na, K, Cs, Mg, Ba, Pt, Pd, Ir, Mo, W, V, Zr, Hf, Ti, Y, Ce, and La (hereinafter also referred to as element (1)), and a porous carrier. ２ The oxygenated catalyst may contain two or more types of element (1). The atomic ratio of element (1) to Rh is preferably 0.001 to 10, more preferably 0.01 to 5. Examples of porous supports include porous oxides such as silica and alumina. The amount of Rh and element (1) supported is, for example, 0.01% by mass to 10% by mass, preferably 0.1% by mass to 5% by mass. Here, the amount of Rh and element (1) supported is the ratio of the total mass of Rh and element (1) to the mass of the porous support.

[0024] C ２ The oxygenated catalyst can be produced by a known method. For example, a catalyst precursor is dissolved in a solvent, the resulting solution is impregnated into a porous support, and the support is activated to produce the oxygenated catalyst. ２ An oxygenated catalyst can be obtained. Examples of catalyst precursors include salts of Rh and salts of element (1). Examples of salts include hydrochlorides, nitrates, formates, acetates, alkoxide salts, and oxyacid salts. Examples of solvents include ethanol, methanol, and water. Examples of activation methods include a method in which the temperature is raised stepwise in a temperature range of 250°C to 600°C in an oxygen-containing atmosphere, and a method in which the temperature is raised stepwise in a temperature range of 100°C to 450°C in a hydrogen gas atmosphere. Additionally, reduction treatment with a reducing agent such as hydrazine or boron hydride may be used as a hydrogen activation treatment. The selection of catalyst precursors, the catalyst production process, and activation treatment conditions are not limited to those described above.

[0025] Rh-supported C ２When producing an oxygenated catalyst, a supporting method is recommended in which a Rh solution is applied to a porous support such as silica or alumina having a porous structure, and then the Rh solution is forced into the pores of the porous support. The Rh solution used in this step is preferably, for example, rhodium chloride, rhodium nitrate solution, hexaamminerhodium acetate solution, or tetraamminerhodium hydroxide solution. C in which Rh and element (1) are supported on a porous support ２ When producing an oxygenated catalyst, element (1) may be contained in a Rh solution, or a solution of element (1) may be separately applied to a porous support carrying Rh. The Rh solution and the solution of element (1) may be simultaneously or sequentially supported by methods such as immersion, dripping, coating, or spraying at a predetermined temperature range.

[0026] C containing Rh and element (1) ２ In the production of the oxygenated catalyst, it is preferable to use at least one chelating agent selected from the group consisting of oxalic acid, citric acid, tartaric acid, lactic acid, and malic acid. By using a chelating agent, the ethanol production activity is improved compared to when a chelating agent is not used. ２ As a method for producing the oxygenated catalyst, for example, a method in which a porous support is impregnated with a Rh solution and an element (1) solution, dried, and further impregnated with a chelating agent solution, followed by activation treatment, can be mentioned.

[0027] The hydrogenation catalyst contains at least one element selected from the group consisting of palladium, iron, nickel, platinum, copper, chromium, zinc, potassium, sodium, cerium, and titanium (hereinafter also referred to as element (2)), and a porous support. The hydrogenation catalyst may contain two or more elements (2). Examples of the porous support include porous oxides such as silica and alumina. The amount of element (2) supported is, for example, 0.01% by mass to 10% by mass, preferably 0.1% by mass to 5% by mass. Here, the amount of element (2) supported is the ratio of the total mass of element (2) to the mass of the porous support.

[0028] The hydrogenation catalyst can be produced by known methods. For example, a catalyst precursor is dissolved in a solvent, the resulting solution is impregnated into a porous support, and an activation treatment is performed to obtain a hydrogenation catalyst. Examples of catalyst precursors include salts of element (2). Examples of salts include hydrochlorides, nitrates, oxyacid salts, and organic acid salts such as oxalic acid. Examples of solvents include ethanol, methanol, and water. Examples of activation treatment methods include a method in which the temperature is gradually increased in an oxygen-containing atmosphere over a temperature range of 250°C to 600°C, and a method in which the temperature is gradually increased in a hydrogen gas atmosphere over a temperature range of 100°C to 450°C. Additionally, hydrogen activation treatment may involve reduction treatment using a reducing agent such as hydrazine or boron hydride. The selection of catalyst precursor, the catalyst production process, and activation treatment conditions are not limited to these.

[0029] C ２ The oxygenation catalyst and the hydrogenation catalyst may be disposed separately, but in terms of ethanol yield and ethanol selectivity, it is preferable to use the oxygenation catalyst and the hydrogenation catalyst in combination. ２ It is preferable that the oxygenation catalyst and the hydrogenation catalyst are mixed and disposed as a composite catalyst. ２ When the oxygenation catalyst and the hydrogenation catalyst are separately arranged, the hydrogenation catalyst is C ２ C ２ It is contacted with the biomass gas after contact with the oxygenated catalyst.

[0030] In the composite catalyst, C for the hydrogenation catalyst ２ The volume ratio of the oxygenated catalyst (C ２ The volume ratio (oxygenation catalyst / hydrogenation catalyst) is preferably 0.1 to 5, more preferably 0.2 to 2. ２ When the ratio of the oxygen-containing catalyst / hydrogenation catalyst) is equal to or greater than the lower limit of the above range, C ２ The oxygen-containing compound yield is better, and when it is not more than the upper limit of the above range, the ethanol selectivity is better.

[0031] The ethanol production facility 50 receives the reformed gas 8 through a composite catalyst introduction facility 62 and converts it into C ２A catalyst mixture preparer 57 is connected to the ethanol production facility 50, which mixes an oxygenation catalyst 58 and a hydrogenation catalyst 59 to prepare a composite catalyst 63. The composite catalyst 63 prepared in the catalyst mixture preparer 57 is introduced into the ethanol production facility 50 by a composite catalyst introduction facility 62.

[0032] The ethanol production facility 50 is connected to a shift reaction hydrogen production facility (shift reaction facility) 53 via a gas-liquid separator 52. The shift reaction hydrogen production facility 53 generates hydrogen and carbon dioxide by shift reaction of the reaction gas generated in the ethanol production facility 50 with carbon monoxide and methane contained in the residual gas after separation of the ethanol-containing liquid product in the gas-liquid separator 52 and water vapor (shift reaction step).

[0033] The shift reaction hydrogen production facility 53 contains H ２ / CO ２ The gas separation facility 54 is connected via a gas pipe 64. The hydrogen and carbon dioxide generated in the shift reaction hydrogen production facility 53 are ２ / CO ２ The gas is supplied to the gas separation facility 54 via a gas pipe 64 .

[0034] The gas separation facility 54 is connected to the hydrogen holder 55 via a hydrogen supply pipe (second piping facility) 79. The carbon dioxide 9 separated and recovered in the gas separation facility 54 is supplied to the reforming-gasification furnace 30 via a carbon dioxide supply pipe (first piping facility) 32. The carbon dioxide supply pipe 32 is provided with a carbon dioxide supply amount regulator 83 that regulates the amount of carbon dioxide supplied to the reforming-gasification furnace 30. The hydrogen holder 55 is connected to a gas mixture preparer 89 via a hydrogen supply pipe 78. The hydrogen supply pipe 78 is provided with a hydrogen supply amount regulator (hydrogen supply amount regulating means) 85. The hydrogen supply amount regulator 85 regulates the amount of hydrogen generated in the water electrolysis facility 40 that is supplied to the hydrogen holder 55 via the hydrogen supply pipe (third piping facility) 51.

[0035] The gas mixture adjuster 89 adjusts the mixture of hydrogen from the hydrogen holder 55 into the reformed gas.

[0036] The pressurized gas circulation supply equipment 88 is H ２ / CO ２The volume ratio of the reformed gas is adjusted and pressurized and circulated.

[0037] The ethanol separation and purification equipment 56 separates and purifies bioethanol 90 from the liquid product containing ethanol.

[0038] The ethanol production facility 50 is connected to a gas-liquid separator 52. The gas-liquid separator 52 is connected to an ethanol separation and purification facility 56 via a crude ethanol piping 77.

[0039] One end of the steam supply pipe 33 is connected to the bottom of the inner cylindrical portion 30a of the reforming-gasification furnace 30. The other end of the steam supply pipe 33 is connected to the clean water 4 via the heat exchanger 31. A steam supply amount regulator 84 may be installed in the steam supply pipe 33.

[0040] One end of the carbon dioxide supply pipe 32 is connected to the bottom of the inner cylindrical portion 30a of the reforming-gasification furnace 30. The other end of the carbon dioxide supply pipe 32 is connected to the gas separation equipment 54. A carbon dioxide supply amount regulator 83 is also installed in the carbon dioxide supply pipe 32. An example of the carbon dioxide supply amount regulator 83 is a mass flow controller. The supply of carbon dioxide to the reforming-gasification furnace 30 may be continuous or intermittent.

[0041] A first reformed gas pipe 35 is connected to the top of the reforming-gasification furnace 30. The first reformed gas pipe 35 discharges the reformed gas 8 from the reforming-gasification furnace 30. The reformed gas 8 is supplied to a gas purifier 36 via the first reformed gas pipe 35. The reformed gas 8 passes through the gas purifier 36 and is connected to the ethanol production facility 50 via a reformed gas supply amount regulator 86, a gas mixture preparer 89, and a pressurized gas circulation facility 88.

[0042] A dust collector 34 equipped with a metal-containing residue separation and recovery means is installed in the first reformed gas piping 35, upstream of the gas purifier 36. A metal-containing residue 3 is discharged from the reformed gasification furnace 30 together with the reformed gas 8. The dust collector 34 separates the reformed gas 8 from the metal-containing residue 3 and recovers the separated metal-containing residue 3. Because the metal-containing residue 3 contains useful metal elements derived from the biomass, the recovered metal-containing residue 3 is introduced into the biomass receiver 11 via a metal-containing residue discharge piping 39, a metal-containing residue supply amount adjuster (metal-containing residue supply amount adjustment means) 82, and a metal-containing residue supply facility 37, and is mixed with the biomass.

[0043] The gas purifier 36 is installed midway along the first reformed gas pipe 35. A gas mixture preparer 89 is installed downstream of the gas purifier 36 via a reformed gas supply amount adjuster 86.

[0044] The multiple combustion gas pipes supply the combustion gas 6 generated by the air combustor 60 to the exhaust heat utilization equipment described below via a combustion gas pipe 70 and a combustion gas flow rate regulator 61. The combustion gas pipe 71 supplies combustion gas to the biomass dryer 12, a combustion gas pipe 72 supplies combustion gas to the carbonization furnace, a combustion gas pipe 73 supplies combustion gas to the reforming gasification furnace 30, a combustion gas pipe 74 supplies combustion gas to the steam heat exchanger 31, a combustion gas pipe 75 supplies combustion gas to the ethanol production facility 50, and a combustion gas pipe 76 supplies combustion gas to the shift reaction hydrogen production facility 53. The system may also be provided with a gas temperature regulator for regulating the temperature of the combustion gas and a gas flow rate regulator for regulating the flow rate of the combustion gas.

[0045] The biomass supply rate regulator 80 is provided between the biomass receiver 11 and the biomass dryer 12, and regulates the amount of biomass 1 supplied to the biomass dryer 12. The biomass supply rate regulator 80 has a moisture content measuring means.

[0046] The carbonized material supply amount adjuster 81 is provided between the carbonization furnace 20 and the reforming gasification furnace 30 and adjusts the amount of carbonized material 2 supplied to the reforming gasification furnace 30 .

[0047] The carbon dioxide supply amount regulator 83 regulates the amounts of steam and carbon dioxide supplied to the reforming-gasification furnace 30 .

[0048] The reformed gas supply amount adjuster 86 adjusts the amount of reformed gas supplied to the reforming-gasification furnace 30 .

[0049] The biomass supply equipment 91 adjusts the amount of biomass 1 supplied to the carbonization furnace 20 .

[0050] The carbide supply equipment 92 adjusts the amount of carbide 2 supplied to the reforming gasification furnace 30 .

[0051] The reformed gas supply facility 93 supplies steam and carbon dioxide to the reforming-gasification furnace 30 .

[0052] The metal-containing residue separator / recoverer 94 separates and recovers the metal-containing residue generated together with the reformed gas from the reformed gas.

[0053] The catalyst mixing amount adjuster 95 adjusts the amount of metal-containing residue supplied to the biomass 1 .

[0054] The air combustor 60 is connected to the carbonization furnace 20. The air combustor 60 generates high-temperature combustion gas 6 by air-combusting the pyrolysis gas (pyrolysis gas 5) generated in the carbonization furnace 20 using an air blower 41.

[0055] According to the bioethanol production facility of this embodiment, the carbonization rate of biomass can be increased, the reformed gas can be produced efficiently, and the subsequent bioethanol can be produced economically and stably.

[0056] [Bioethanol Production Method] The bioethanol production method of this embodiment includes a carbonization step of carbonizing biomass to produce a carbonized product, a reformed gasification step of carrying out a mixed gasification reaction of the carbonized product with water vapor and carbon dioxide to produce a reformed gas containing hydrogen, carbon monoxide, methane, and carbon dioxide, and a C ２ The bioethanol production method of the present embodiment includes an ethanol production step of producing ethanol by contacting the reformed gas with an oxygenated catalyst and a hydrogenation catalyst, and a mixing step of separating and recovering a metal-containing residue generated together with the reformed gas in the reformed-gasification step from the reformed gas and mixing the metal-containing residue with the biomass.

[0057] (Biomass) Examples of biomass (or biomass body) used in this embodiment include forest felling materials such as cedar, pine, and bamboo, agricultural products and by-products such as rice straw and sugarcane, construction waste, and industrial waste such as cotton and textile products.

[0058] The biomass (or biomass itself) is preferably a pulverized product obtained by pulverizing and drying biomass produced or discarded in forestry or agriculture. The size of the pulverized product is, for example, 10 mm to 100 mm. One type of biomass may be used alone, or two or more types may be used in combination.

[0059] In addition to carbon, the biomass 1 may contain alkali metals and alkaline earth metals including sodium, potassium, lithium, cesium, calcium, magnesium, barium, etc., metalloids such as boron, and metals such as aluminum, iron, and nickel, and these metals may also be added and mixed in. When these metals are contained in the biomass, this is preferable because it reduces tar production in the carbonization step, promotes the carbonization reaction, and allows for more efficient generation of reformed gas in the subsequent reforming-gasification step.

[0060] In this embodiment, in order to ensure that the crushed biomass chips contain an appropriate amount of metals, in addition to adjusting the type and amount of biomass, substances such as metal compounds that serve as sources of the above-mentioned metals may be mixed with the biomass. As such a metal source, for example, it is preferable to use the metal-containing residue 3 generated together with the reformed gas 8 in the biomass reforming-gasification process. This metal-containing residue is a residue that is separated and recovered from the reformed gas generated in the reforming-gasification process. The metal-containing residue may usually be recovered as a solid such as a metal oxide, carbide, or metal salt.

[0061] The timing for mixing a metal source such as a metal-containing residue with biomass may be a mixing step before the carbonization step, or at least one of the metal-containing residue and the metal source may be directly charged into a carbonization furnace. When mixing at least one of the metal-containing residue 3 and the metal source before the carbonization step, for example, the metal-containing residue and the metal source may be charged into a biomass receiver and / or a dryer for drying the biomass and mixed therein. In this embodiment, the metal-containing residue may be supplied to the biomass continuously or intermittently.

[0062] Examples of methods for mixing metals with biomass include a method of immersing biomass in a solution in which a metal source such as a metal-containing residue is dissolved or dispersed in a solvent such as an acid or alkaline aqueous solution, alcohol, ether, or hydrocarbon, and an addition method in which the solution is sprayed onto biomass to mix and support the metal components on the biomass.

[0063] In the carbonization process of this embodiment, the presence of the metals in the biomass raw material promotes carbonization and increases the carbonization rate. The metal content in the metal-containing residue is typically approximately 0.01 g to 100 g, or 0.1 g to 50 g, per 1 kg of the metal-containing residue. The mass ratio of the metal-containing residue to 1 kg of biomass (metal-containing residue / biomass) can range from 0.01 to 0.99, or 0.1 to 0.9, for example. In this embodiment, when the metal element content of the metal-containing residue and the mass ratio of the metal-containing residue to biomass are within the above ranges, the carbonization rate in the biomass carbonization process tends to be improved, and the tar removal rate also tends to be superior. The increased carbonization rate ultimately leads to increased production of char, reformed gas, and bioethanol. The metal content of the metal-containing residue in this embodiment can be measured by ion chromatography, ICP atomic emission spectroscopy, and X-ray fluorescence analysis.

[0064] (Carbonization process) In the bioethanol production method of this embodiment, a carbonization process is carried out in which biomass 1 is carbonized to produce a carbonized material 2. In the carbonization process, the raw material biomass is heated in a low-oxygen or oxygen-free state to cause pyrolysis. Pyrolysis of the biomass produces a carbonized material and a dry distillation gas containing a low-molecular-weight fuel gas and heavy fuel components such as tar. In the bioethanol production method of this embodiment, the carbonization process is carried out using a carbonization furnace 20.

[0065] The carbonization furnace can be appropriately selected from known carbonization furnaces, such as a carbonization furnace equipped with an external or internal heating device, or a carbonization furnace equipped with a device for transporting heated material, such as a screw or rotary.

[0066] The carbonization conditions for the carbonization step in the bioethanol production method of this embodiment are as follows: The heating temperature in the carbonization step is, for example, preferably 200°C or higher and 600°C or lower, and more preferably 250°C or higher and 500°C or lower. The residence time in the carbonization step in the bioethanol production method of this embodiment is, for example, preferably 5 minutes or higher and 100 minutes or lower, and more preferably 10 minutes or higher and 60 minutes or lower. By pyrolyzing the raw material biomass at the above heating temperature and heating time, a carbonized product can be efficiently obtained.

[0067] In the carbonization step of the bioethanol production method of this embodiment, the raw material may be supplied to the carbonization furnace continuously or intermittently. The metal-containing residue may be supplied to the carbonization furnace continuously or intermittently.

[0068] (Air Combustion Process of Dry Distillation Gas) In the bioethanol production method of this embodiment, the dry distillation gas 5 generated together with the carbonized material in the carbonization process may be separated from the carbonized material, recovered, and combusted to generate high-temperature combustion gas 6. Such combustion gas may be introduced into at least one of the carbonization process, the reforming gasification process described below, the bioethanol production process, and the shift reaction hydrogen production process, and used as exhaust gas for heating. Specifically, since the dry distillation gas contains hydrogen, lower hydrocarbons, and heavy fuel components such as tar, it is transferred to an air combustion furnace 60 equipped with an air blower, and is combusted in an air atmosphere, for example, to produce a high-temperature combustion gas (1000°C to 1200°C) from which heavy fuel components such as tar have been removed. ｏ This combustion gas can be used as a heat source and transported via piping equipment or the like to the various steps of the manufacturing method of this embodiment or to a heating step such as a biomass dryer in an external system, and used as exhaust heat gas for heating the various steps.

[0069] By utilizing the heat of the combustion gas as exhaust heat gas for heating in each process of the bioethanol production method of this embodiment, heating can be performed without using an external fuel (heavy oil, electricity, etc.) or by using a smaller amount of combustion gas generated by air combustion of an external fuel than conventional methods. Examples of production processes in this embodiment that can utilize such exhaust heat gas include biomass drying, the carbonization process (heating the carbonization furnace 20), the reforming-gasification process (heating the reforming-gasification furnace 30), the bioethanol production process, and heating the steam heat exchanger 31 and the shift reaction hydrogen production facility 53. This not only reduces the economic benefits of reforming gas and bioethanol production costs, but also contributes to the suppression of global warming by reducing carbon dioxide emissions.

[0070] (Reformed gasification process) In the bioethanol production method of this embodiment, the carbonized material obtained in the carbonization process is introduced into a connected gasification furnace, and the carbonized material is subjected to a co-gasification reaction with water vapor and carbon dioxide to produce hydrogen, carbon monoxide, methane, and carbon dioxide (hereinafter, referred to as H ２ , CO, CH ４ and CO ２In the reformed gasification step of the bioethanol production method of this embodiment, the reformed gas is thought to be produced by the following reformed gasification reaction between char, steam, and carbon dioxide: (1) Reaction between char and steam: C+H ２ O → H ２ + CO (2) Reaction of carbide with carbon dioxide: C + CO ２ → 2CO (3) Shift reaction: CO + H ２ O → CO ２ +H ２ (4) Methanation reaction: C + 2H ２ →CH ４ In the reforming gasification process of the bioethanol production method of this embodiment, the reactions (1) and (2) are particularly promoted because carbon dioxide is mixed and supplied together with water vapor. This allows for efficient production of reformed gas, increasing the amount of reformed gas produced. By using carbon dioxide mixed with water vapor in the above reaction, the amount of reformed gas produced can be increased, for example, by 1.2 to 2.5 times compared to reforming gas produced using water vapor alone.

[0071] The water vapor used in the reforming-gasification step of the bioethanol production method of this embodiment can be water vapor 7 generated by heating water such as clean water 4. The carbon dioxide 9 used in the reforming-gasification step of the bioethanol production method of this embodiment can be introduced into the reforming-gasification furnace from a system separate from the bioethanol production method of this embodiment, or carbon dioxide discharged from a shift reaction hydrogen production facility 53 described below can be introduced into the reforming-gasification furnace 30.

[0072] The supply of steam to the reforming gasification furnace 30 connected to the charcoal 2 in the reforming-gasification step of the bioethanol production method of this embodiment can be appropriately adjusted by the charcoal supply rate adjuster 81 to efficiently produce the reformed gas, and can be, for example, 10 kg / h to 10,000 kg / h, or 50 kg / h to 5,000 kg / h. The amount of steam supplied to the reforming gas furnace can be appropriately adjusted. For example, the amount of steam supplied per kg / h of charcoal supply can be 0.5 kg / h to 10 kg / h, or 2 kg / h to 5 kg / h. The amount of carbon dioxide supplied to the reforming gas furnace can be appropriately adjusted. For example, the amount of carbon dioxide supplied per kg / h of charcoal supply can be 0.1 Nm ３ / h or more 10Nm ３ / h or less, or 0.5 Nm ３ / h or more 5Nm ３ / h or less. In addition, the ratio of the supply amount of carbon dioxide to the total supply amount of water vapor 7 and carbon dioxide 9 (CO ２ The supply amount divided by (the supply amount of water vapor+the supply amount of carbon dioxide) is, for example, 1% by volume or more and 85% by volume or less, or 10% by volume or more and 60% by volume or less.

[0073] In the reforming-gasification step of the bioethanol production method of this embodiment, the temperature of the reforming-gasification furnace 30 can be adjusted as appropriate to efficiently produce the reformed gas, and may be, for example, 600° C. to 1200° C., preferably 800° C. to 900° C. As a heating means for the reforming-gasification furnace 30, for example, the combustion gas obtained by burning the dry distillation gas described above may be used as exhaust heat gas for heating.

[0074] Steam 7, for example, is heated in a steam heat exchanger 31 using clean water 4 heated to a temperature in the range of 50°C to 800°C, and then supplied to the reforming-gasification furnace 30. When a heat exchanger or the like is used to heat the clean water, the heat exchanger may be heated by introducing exhaust heat gas from the reforming-gasification furnace. Furthermore, the exhaust heat gas from the steam heat exchanger 31 that has heated the clean water may be introduced into another process (for example, the ethanol production facility 50 and the shift reaction hydrogen production facility 53) and used for heating.

[0075] The pressure in the reforming-gasification furnace 30 in the reforming-gasification step can be adjusted as appropriate, and may be, for example, 0.05 MPa or more and 0.5 MPa or less.

[0076] The reformed gas 8 obtained in the reforming gasification step of the bioethanol production method of this embodiment is hydrogen (H ２ ) and carbon monoxide (CO), typically hydrogen (H ２ ), carbon monoxide (CO), methane (CH ４ ) and carbon dioxide (CO ２ ) is included.

[0077] (Metal-containing residue separation and recovery step) In the present embodiment, the system may include a metal-containing residue separation and recovery step, in which a metal-containing residue generated together with the reformed gas 8 in the reformed-gasification step is separated and recovered from the reformed gas, and the recovered metal-containing residue is supplied to the biomass, a discharge and supply facility, and a supply amount adjustment means. That is, in the reformed-gasification step, metals contained in the char remain as a metal-containing residue 3, and the metal-containing residue 3 is separated and recovered from the reformed gas 8. As a recovery method, for example, a dust collector 34 such as a cyclone and a bag filter is used to separate the reformed gas containing the metal-containing residue discharged from the reformed-gasification furnace from the reformed gas and the metal-containing residue, and the separated metal-containing residue is recovered. The metal-containing residue 3 can be recycled and supplied to the biomass receiver 11, the biomass dryer 12, or the carbonization process prior to the carbonization process, and mixed with the biomass as described above, thereby increasing the carbonization rate and the amount of reformed gas produced in the carbonization and gasification processes of the bioethanol production method of this embodiment. The effect of recycling the metal-containing residue 3 to the biomass 1 to increase the carbonization rate of the biomass and the amount of reformed gas produced may increase with the number of recycles in this embodiment.

[0078] Since the metals contained in the biomass 1 are recovered as residues from the gasification process, the metal-containing residue 3 contains at least one element selected from the group consisting of metals contained in the biomass, such as alkali metals and alkaline earth metals such as sodium, potassium, lithium, calcium, magnesium, and barium, metalloids such as boron, aluminum, iron, and nickel.

[0079] The reformed gas 8 from which the metal-containing residue 3 has been removed in the separation device is transferred to the bioethanol production process described below and used for bioethanol production, or it may be used for other purposes, such as hydrogen production and power generation in a gasification power generation facility.

[0080] (Gas Purification Process of Reformed Gas) The gas purifier 36 removes sulfur-containing components from the reformed gas 8. The reformed gas 8 generated by the mixed gasification of the carbonized material 2 with water vapor 7 and carbon dioxide 9 contains sulfur-containing components such as hydrogen sulfide and COS. These sulfur-containing components act as catalyst poisons and may reduce catalytic activity and impair stability in bioethanol production facilities. Removing the sulfur-containing components improves the stability of catalytic activity in bioethanol production facilities.

[0081] The gas purifier 36 preferably includes a gas purification member in which at least one metal selected from the group consisting of Cu, Zn, Cr, Ce, Fe, Mo, and Co is supported on a porous carrier such as silica, alumina, or zeolite. When such a gas purification member is brought into contact with the biomass gas, sulfur-containing components bond with the metal and the porous carrier and are chemically removed from the reformed gas 8.

[0082] However, the gas purifier 36 is not limited to the chemical method described above. For example, other common techniques, such as gas purification techniques using gas adsorbents such as activated carbon and various zeolites, can also be used in combination. In addition to desulfurization, the gas purification equipment may also remove nitrogen-containing components such as ammonia and NOx, and chlorine-containing components such as HCl.

[0083] (Bioethanol production process) The ethanol production facility 50 is ２ The reformed gas 8 is treated with an oxygenation catalyst 58 and a hydrogenation catalyst 59.２ When the reformed gas 8 is brought into contact with the oxygen-containing catalyst 58, the H contained in the reformed gas 8 ２ , CO, CO ２ , C.H. ４ From C such as acetic acid, acetaldehyde, and ethanol ２ Oxygen-containing compounds are produced. ２ Derivatives of oxygen-containing compounds may also be produced as by-products. Furthermore, when the reaction mixture is brought into contact with a hydrogenation catalyst 59, acetic acid, acetaldehyde, methyl acetate, ethyl acetate, and the like are hydrogenated and efficiently converted to ethanol. This increases the amount of ethanol produced and also increases the ethanol selectivity.

[0084] Next, the reformed gas 8 is pressurized to a predetermined reaction pressure by a booster in a pressurized gas circulation supply system (reformed gas circulation amount adjustment means) 88, and is continuously circulated and supplied to the ethanol production facility 50. The pressurized gas circulation supply system 88 adjusts the amount of reformed gas circulated to the composite catalyst 63 (circulation amount). The reformed gas supplied to the ethanol production facility 50 is C ２ The mixture is brought into contact with a composite catalyst 63 prepared by mixing an oxygenation catalyst 58 and a hydrogenation catalyst 59 to produce a liquid product containing bioethanol.

[0085] The reaction pressure in the ethanol production facility 50 is preferably 0.1 MPa to 5 MPa, more preferably 1 MPa to 3.5 MPa. The reaction temperature is preferably 200°C to 350°C, more preferably 250°C to 300°C. The space velocity of the biomass gas (SV: synthesis gas velocity L / h / catalyst volume L) is 1000 h －１ ~35,000 hours －１ is preferable, and 3000h －１ ~25,000 hours －１ In the ethanol production facility 50 of this embodiment, for example, bioethanol can be obtained with an ethanol selectivity of 50% to 85% and an ethanol yield (STY: kg / L-cat / h) of 0.25 kg / L-cat / h to 0.85 kg / L-cat / h.

[0086] The outlet of the ethanol production facility 50 is connected to a gas-liquid separator 52. A liquid product containing ethanol (also called crude ethanol) is separated from the reaction gas. The gas-liquid separator may be a known type.

[0087] (H ２ and CO ２ The reaction gas separated by the gas-liquid separator may be circulated and supplied to the bioethanol production facility. ２ The mixed gas containing ２ and CO ２ may be manufactured.

[0088] The shift reaction hydrogen production facility 53 produces hydrogen by bringing CO and methane in the reaction gas separated by the gas-liquid separator 52 into contact with a shift reaction catalyst in the presence of water vapor through the shift reaction described below. ２ and CO ２ Produce a mixed gas of: 1. CO + H ２ O=H ２ +CO ２ 2. CH ４ +2H ２ O=4H ２ +CO ２

[0089] In this embodiment, various shift reaction catalysts can be selected depending on the intended use. For example, the shift reaction catalyst may contain at least one element selected from the group consisting of iron, ruthenium, nickel, copper, zinc, potassium, lithium, magnesium, chromium, cobalt, molybdenum, zirconia, titanium, cerium, lanthanum, and neodymium (hereinafter also referred to as element (3)). The shift reaction catalyst may contain two or more elements (3). The element (3) may be supported on a carrier. Examples of the carrier include porous oxides (porous oxide carriers) such as silica and alumina.

[0090] (CO ２ Supply) H generated in the shift reaction hydrogen production facility 53 ２ and CO ２ The mixed gas is separated into carbon dioxide 9 in a gas separation facility 54, and the recovered CO２ may be supplied to the reforming-gasification furnace 30 via the carbon dioxide supply regulator 83 (supply step).

[0091] (Hydrogen supply) The remaining hydrogen is supplied to the hydrogen holder 55 via the hydrogen supply pipe 79. The reformed gas and hydrogen may be mixed and adjusted and supplied to the bioethanol production facility (supply step). In this embodiment, the H ２ By adjusting the CO / CO mixture ratio via a gas mixture adjuster, the bioethanol production yield and ethanol selectivity can be significantly improved.

[0092] The gas separation equipment 54 separates the H generated in the shift reaction hydrogen production equipment 53. ２ and CO ２ CO from the mixed gas ２ The gas separation equipment 54 may be, for example, a PSA gas separation device or a ceramic membrane gas separation device. Either one of these gas separation devices may be used, or both may be used.

[0093] In this embodiment, the shift reaction hydrogen production facility 53 and the gas separation facility 54 are ２ / CO ２ The CO 2 discharged from the gas separation facility 54 is supplied via the carbon dioxide supply pipe 32. ２ is supplied to the reforming gasification furnace 30. Hydrogen is also supplied to the hydrogen holder 55 via the gas separation equipment 54 and the hydrogen supply pipe 79.

[0094] In this embodiment, the water electrolysis equipment 40 is also connected to a hydrogen holder 55 via a hydrogen supply pipe 51 and a water electrolysis hydrogen supply regulator 87. Commercially available electricity can be used to power the water electrolysis equipment, but it is preferable to use renewable energy sources such as solar and wind power, as well as electricity obtained from nuclear reactors, in order to reduce carbon dioxide emissions in the bioethanol production process.

[0095] The hydrogen holder 55 is connected to a gas mixture adjuster 89 via a hydrogen supply pipe 79. Hydrogen 10, the supply amount of which is adjusted by a hydrogen supply amount adjuster 85, is mixed and supplied from the hydrogen holder 55 to the reformed gas 8. This increases the hydrogen / CO volume ratio in the reformed gas 8, and preferably increases the amount of H ２ After adjusting the / CO volume ratio to 1 to 3, more preferably to 1.5 to 2.5, the gas is pressurized and circulated in a pressurized gas circulation supply facility 88, and introduced into the ethanol production facility 50 for the ethanol production reaction.

[0096] (Bioethanol Purification Process) In this embodiment, the crude ethanol separated in the gas-liquid separator 52 is purified through an ethanol separation and purification system 56 equipped with a distillation column and a membrane separator. The distillation column concentrates and separates ethanol from the liquid ethanol product, and also separates and recovers low-boiling by-product residues, such as acetic acid, acetaldehyde, propanol, and methanol, from the liquid product. The distillation column may be a known type, such as a multi-stage Raschig ring distillation column or a silicon membrane separator. In this embodiment, the ethanol concentration of the crude ethanol liquid product produced in the bioethanol production facility is, for example, 53% to 60% by mass. The ethanol is concentrated to 80% to 85% using a commercially available distillation column. For example, the ethanol can be purified to an even higher ethanol concentration using a commercially available ceramic membrane separator. The ethanol concentration of the purified product is, for example, 86% to 99%.

[0097] According to the bioethanol production method of this embodiment, the carbonization rate of biomass can be increased, making it possible to efficiently produce reformed gas, and subsequently, bioethanol can be produced economically and stably.

[0098] Although the present invention has been described above by showing exemplary embodiments, the present invention is not limited to the above exemplary embodiments and can be freely modified within the scope of the present invention.

[0099] Examples of the present invention are shown below, but the following examples are merely illustrative of the invention and are not intended to limit the scope of the present invention.

[0100] (Test 1) A test to produce bioethanol was carried out using the bioethanol production apparatus configured as shown in Figure 1. In this test, 250 kg / h of construction waste chips (moisture content 27% by mass) were fed into the dryer and carbonization furnace, and the carbonization rate (wt%) of the carbonized material in the carbonization furnace and the amount of reformed gas produced in the reforming gasification furnace (Nm ３ In this test, the reforming gasification furnace was fed with 105 kg / h of steam and CO ２ 70 Nm ３ The results of experiments on reformed gasification and bioethanol production in cases where the metal-containing residue (10 kg / h) separated and recovered in the cyclone dust collector was recycled and fed to a receiver for construction waste chips are shown in Example 1 and Comparative Example 1.

[0101] Reformed gas component composition and CO, hydrogen, and CO in the outlet gas of the shift reaction hydrogen production unit ２ , C.H. ４ Analysis of liquid components, including ethanol, generated in the ethanol production facility was measured using a thermal conductivity gas chromatograph analyzer (Shimadzu Corporation GC-14B) and an FI D gas chromatograph analyzer (Shimadzu Corporation GC-8A) filled with Gaskuropack and molecular sieve 13X. The flow rate of the exhaust gas was measured using a wet gas flow meter. The metal element content of the metal-containing residue was measured using an ICP optical emission spectrometer (Shimadzu Corporation ICPS-8100) and an X-ray fluorescence analyzer (Hitachi High-Tech EA1400). The metal content per kg of the metal-containing residue obtained in this test was 25 g / kg of Na, 85 g / kg of K, 36 g / kg of Ca, 7.5 g / kg of Mg, 5 g / kg of Ba, 7.5 g / kg of Fe, and 1.8 g / kg of Ni.

[0102] (C ２ Oxygenated catalyst 1) Chlorides or nitrates of Rh, Mg, V, Hf, Ir, and Ce were dissolved in a mixed solvent of ethanol and water in an atomic ratio of 1:0.3:0.2:0.5:0.3 to obtain an aqueous ethanol solution. This aqueous ethanol solution was applied to a silica support (specific surface area 315 m). ２After impregnating the silica carrier with Rh, Mg, V, Hf, Ir, and Ce, the catalyst was activated by heating the catalyst to 150°C over 1 hour under a mixed gas flow of hydrogen and nitrogen gas (1:3 volume ratio), maintaining the temperature for 2 hours, then heating the catalyst to 450°C over 2 hours, maintaining the temperature for 2 hours, and then cooling the catalyst to room temperature. ２ Oxygenated catalyst 1 was prepared.

[0103] (Hydrogenation catalyst 1) Cu, Cr nitrate, Ti, and Mo chloride were dissolved in a mixed solvent of ethanol and water so that the atomic ratio of Cu:Cr:Ti:Mo was 1:0.8:0.2:0.15, to obtain an ethanol aqueous solution. This ethanol aqueous solution was applied to a silica support (specific surface area: 365 m). ２ After impregnating the catalyst with Cu, Cr, Ti, and Mo, an activation treatment was carried out by heating the catalyst to 100°C over 1 hour in a stream of a mixed gas of hydrogen and nitrogen gas (1:2 volume ratio), maintaining the temperature for 2 hours, heating the catalyst to 450°C over 2 hours, maintaining the temperature for 3 hours, and then cooling the catalyst to room temperature. This resulted in the preparation of hydrogenation catalyst 1 in which Cu, Cr, Ti, and Mo were supported on a silica carrier. ２ A composite catalyst prepared by mixing 100 kg of oxygenated catalyst and 200 kg of hydrogenation catalyst in a commercially available mixer was packed into a titanium-coated stainless steel reactor. Bioethanol was produced by contacting the reformed gas with the composite catalyst. The bulk density of the prepared catalyst in this test was 0.5 kg / L.

[0104]

[0105] These results showed that the carbonization rate, amount of reformed gas produced, and amount of ethanol produced in the carbonization process using biomass raw materials were significantly improved when the metal-containing residue was recycled and supplied (Example 1) compared to when it was not recycled and supplied (Comparative Example 1).

[0106] (Test 2) Using rice straw as agricultural waste, a test of carbonization, reformed gasification, and ethanol production was conducted in the same manner as in Test 1. Rice straw was fed at a rate of 350 kg per hour. The carbonization operation was carried out at a carbonization furnace temperature of 250°C to 420°C. The reformed gasification process of the carbonized material was carried out at a temperature of 900°C, with 150 kg / h of steam and CO ２ 100Nm ３ / h (Example 2), and when steam was supplied alone at 150 kg / h (Comparative Example 2), the reformed gas production amount (Nm ３ / h), the reformed gas component composition (vol%), and the test results of ethanol production (kg-EtOH / h) in bioethanol production using the reformed gas are shown in Table 2.

[0107] In this test, the metal-containing residue separated and recovered by the cyclone dust collector was mixed into a rice straw receiver at a rate of 15 kg per hour, and carbonization and gasification were carried out. The metal contents per kg of the metal-containing residue obtained in this test were Na 45 g / kg, K 65 g / kg, Ca 50 g / kg, Mg 15 g / kg, Ba 2.5 g / kg, Li 1.5 g / kg, Fe 2.8 g / kg, and Ni 0.5 g / kg.

[0108] (C ２ Oxygenated catalyst 2) Chlorides of Rh, Mn, Li, Sc, and Ce were dissolved in a mixed solvent of ethanol and water in an atomic ratio of 1:0.05:0.30:0.10:0.05 to obtain an aqueous ethanol solution. This aqueous ethanol solution was applied to a silica support (specific surface area 385 m). ２ After impregnating the silica carrier with Rh, Mn, Li, Sc, and Ce, the catalyst was activated by heating the catalyst to 100°C over 1 hour under a mixed gas flow of hydrogen and nitrogen gas (1:4 volume ratio), maintaining the temperature for 2 hours, heating the catalyst to 400°C over 2 hours, maintaining the temperature for 2 hours, and then cooling the catalyst to room temperature. ２ Oxygenated catalyst 2 was prepared.

[0109] (Hydrogenation catalyst 2) Nitrates of Pd, Cu, Zn, K, and Zr were dissolved in a mixed solvent of ethanol and water so that the atomic ratio of each element was 1:0.8:0.2:0.15 to obtain an ethanol aqueous solution. This ethanol aqueous solution was then added to a silica support (specific surface area: 265 m). ２After impregnating the catalyst with Pd, Cu, Zn, K, and Zr, the catalyst was activated by heating it to 100°C over 1 hour under a mixed gas flow of hydrogen and nitrogen gas (1:2 volume ratio), maintaining the temperature for 2 hours, heating it to 400°C over 2 hours, maintaining the temperature for 2 hours, and then cooling it to room temperature. This resulted in the preparation of hydrogenation catalyst 2, in which Pd, Cu, Zn, K, and Zr were supported on a silica carrier. The bulk density of the prepared catalyst in this test was 0.5 kg / L. ２ The oxygenation catalyst (160 kg) and the hydrogenation catalyst (320 kg) were mixed in a mixer and prepared, and the resulting composite catalyst was packed into a titanium-coated stainless steel reactor. Bioethanol was produced by contacting the reformed gas with the composite catalyst.

[0110]

[0111] From these results, it is clear that the amount of water vapor and CO ２ It was shown that the reformed gas composition, gas production amount, and ethanol production amount under the mixed supply conditions (Example 2) were significantly increased compared to the case where steam was supplied alone (Comparative Example 2).

[0112] (Test 3) In the same embodiment as Test 2, cedar chips (moisture content 35%) were used as biomass, and carbonization and gasification were carried out at 450 kg / h. The generated reformed gas was C ２ Bioethanol was produced by contacting the reaction gas separated by a gas-liquid separator in the ethanol production facility with a composite catalyst prepared by mixing an oxygen-containing catalyst and a hydrogenation catalyst. In this test, the reaction gas was introduced into a shift reaction hydrogen production facility, and the hydrogen and CO generated were ２ CO from mixed gas using ceramic membrane separation equipment ２ The residual hydrogen separated from the hydrogen was stored in a hydrogen holder. Hydrogen was supplied from the hydrogen holder to the reformed gas by gas mixture preparation, and the H ２ Table 3 shows the CO conversion (ethanol / CO molar ratio %), ethanol selectivity (%), and ethanol yield (STY: g-EtOH / L-cat / h) in the case where the ethanol / CO volume ratio was adjusted to 2.5 (Example 3) and in the case where no hydrogen was supplied (Example 4).

[0113]

[0114] These results show that when hydrogen generated in the shift reaction hydrogen production facility is supplied to the reformed gas (Example 3), the ethanol selectivity and ethanol yield are increased compared to when hydrogen is not supplied (Example 4).

[0115] (Test 4) In the same ethanol production apparatus and embodiment as in Example 1, ２ The oxygenation catalyst 1 and the hydrogenation catalyst 1 were mixed in a mass ratio of 1:1 using a catalyst mixer to prepare a composite catalyst. The resulting composite catalyst was packed into a titanium-coated stainless steel reactor tube. The reformed gas was then pumped under 2.5 MPa, 285°C, and SV=25,000 h. －１ When ethanol is produced by catalytic circulation reaction on a composite catalyst (Example 5), the same amount of C ２ Table 4 shows the CO conversion, ethanol selectivity, and bioethanol yield (STY: g-EtOH / L-cat / h) in ethanol production when the oxygenated catalyst 1 was packed in the upper layer and the hydrogenated catalyst 1 was packed in the lower layer separately in a layered manner in a reactor (Example 6).

[0116]

[0117] This results in C ２ When a composite catalyst prepared by mixing an oxygenation catalyst and a hydrogenation catalyst was used (Example 5), C ２ It was shown that the ethanol yield and ethanol selectivity were improved compared to the case where the oxygenation catalyst and the hydrogenation catalyst were packed in layers separately (Example 6).

[0118] According to the present invention, it is possible to provide a bioethanol production method and a bioethanol production device that can efficiently produce reformed gas using biomass and subsequently produce bioethanol economically and stably.

[0119] LIST OF SYMBOLS 1 Biomass 2 Carbonized material 3 Metal-containing residue 4 Clean water 5 Dry distillation gas (including tar) 6 Combustion gas 7 Steam 8 Reformed gas 9 Carbon dioxide 10 Hydrogen 11 Biomass receiver 12 Biomass dryer 20 Carbonization furnace 30 Reformed gasification furnace 31 Steam heat exchanger 32 Carbon dioxide supply pipe 33 Steam supply pipe 34 Dust collector 35 First reformed gas pipe 36 Gas purifier 37 Metal-containing residue supply equipment 38 Metal-containing residue receiver 39 Metal-containing residue discharge pipe 40 Water electrolysis equipment 41 Air blower 50 Ethanol production equipment 51 Hydrogen supply pipe 52 Gas-liquid separator 53 Shift reaction hydrogen production equipment 54 Gas separation equipment 55 Hydrogen holder 56 Ethanol separation and purification equipment 57 Catalyst mix preparer (catalyst mix preparer) 58 C ２ Oxygenation catalyst 59 Hydrogenation catalyst 60 Air combustor 61 Combustion gas flow rate regulator 62 Composite catalyst introduction equipment 63 Composite catalyst 64 H ２ / CO ２ Gas piping 70 Combustion gas piping 71 Combustion gas piping 72 Combustion gas piping 73 Combustion gas piping 74 Combustion gas piping 75 Combustion gas piping 76 Combustion gas piping 77 Crude ethanol piping 78 Hydrogen supply piping 79 Hydrogen supply piping 80 Biomass supply rate regulator (biomass supply rate regulator means) 81 Charcoal supply rate regulator (charcoal supply rate regulator means) 82 Metal-containing residue supply rate regulator (metal-containing residue supply rate regulator means) 83 Carbon dioxide supply rate regulator (carbon dioxide supply rate regulator means) 84 Water vapor supply rate regulator 85 Hydrogen supply rate regulator 86 Reformed gas supply rate regulator (reformed gas supply equipment) 87 Water electrolysis hydrogen supply rate regulator 88 Pressurized gas circulation supply equipment 89 Gas mixture adjuster 90 Bioethanol 91 Biomass supply equipment 92 Charcoal supply equipment 93 Reformed gas supply equipment 94 Metal-containing residue separation and recovery device (metal-containing residue separation and recovery means) 95 Catalyst mixed amount adjuster (catalyst mixed amount adjustment means) 100 Bioethanol production device

Claims

1. A carbonization step of carbonizing biomass to produce a carbonized product; a reforming gasification step of carrying out a mixed gasification reaction of the carbonized product with steam and carbon dioxide to produce a reformed gas containing hydrogen, carbon monoxide, methane, and carbon dioxide; and a process for converting the reformed gas into C ２ A method for producing bioethanol, comprising: an ethanol production step of producing ethanol by contacting a biomass with an oxygenated catalyst and a hydrogenation catalyst; and a mixing step of separating and recovering a metal-containing residue generated together with the reformed gas in the reformed-gasification step from the reformed gas, and mixing the metal-containing residue with the biomass.

2. The method for producing bioethanol according to claim 1, wherein the metal-containing residue contains at least one element selected from the group consisting of alkali metals, alkaline earth metals, metalloids, aluminum, iron, and nickel.

3. A method for producing bioethanol according to claim 1, further comprising a shift reaction step of producing hydrogen and carbon dioxide by shift reaction of carbon monoxide and methane contained in the residual gas after separating a liquid product containing ethanol from the gas produced in the ethanol production step with water vapor.

4. A method for producing bioethanol as described in claim 3, comprising a supply process for separating and recovering carbon dioxide from the mixed gas of hydrogen and carbon dioxide generated in the shift reaction process, supplying the recovered carbon dioxide to the reforming gasification process, and supplying the hydrogen to the reforming gas.

5. The method for producing bioethanol according to claim 3, wherein the shift reaction step uses a shift reaction catalyst containing at least one element selected from the group consisting of iron, ruthenium, nickel, copper, zinc, potassium, lithium, magnesium, chromium, cobalt, molybdenum, zirconia, titanium, cerium, lanthanum, and neodymium, and a porous oxide support.

6. A method for producing bioethanol according to any one of claims 1 to 5, wherein the dry distillation gas generated together with the carbonized material in the carbonization process is subjected to air combustion, and the generated combustion gas is used as a heat source to heat at least one of the carbonization process, the reformed gasification process, the ethanol production process, and the shift reaction process.

7. Above C ２ The oxygenated catalyst comprises Rh, at least one element selected from the group consisting of Mn, Sc, Li, Na, K, Cs, Mg, Ba, Pt, Pd, Ir, Mo, W, V, Zr, Hf, Ti, Y, Ce, and La, and a porous carrier. The method for producing bioethanol according to claim 1.

8. The method for producing bioethanol according to claim 1, wherein the hydrogenation catalyst comprises at least one element selected from the group consisting of palladium, iron, nickel, platinum, copper, chromium, zinc, potassium, sodium, cerium, and titanium, and a porous carrier.

9. In the ethanol production process, ２ A composite catalyst prepared by mixing an oxygen-containing catalyst and the hydrogenation catalyst is used, and the C relative to the hydrogenation catalyst in the composite catalyst is ２ The volume ratio of the oxygenated catalyst (C ２ The method for producing bioethanol according to claim 1, wherein the ratio of oxygenated catalyst to hydrogenated catalyst is 0.1 or more and 5 or less.

10. A biomass dryer comprising: a reforming gasification furnace; a biomass supply facility; a biomass supply rate adjusting means; a biomass dryer having a means for adjusting and controlling the dryness of the biomass; a carbonization furnace having a temperature rise adjusting means; a carbonized material supply facility for supplying carbonized material to the reforming gasification furnace; a carbonized material supply rate adjusting means for adjusting the amount of carbonized material supplied to the reforming gasification furnace; a supply facility for supplying steam and carbon dioxide to the reforming gasification furnace; a carbon dioxide supply rate adjusting means for adjusting the amount of steam and carbon dioxide supplied to the reforming gasification furnace; a reformed gas supply facility for supplying reformed gas to the reforming gasification furnace; ２ a bioethanol production facility that produces bioethanol by contacting the reformed gas with an oxygenation catalyst and a hydrogenation catalyst; a separation and recovery means that separates and recovers a metal-containing residue generated together with the reformed gas from the reformed gas; a metal residue supply facility that supplies the recovered metal-containing residue to the biomass and mixes it with the biomass; and a metal-containing residue supply amount adjustment means that adjusts the amount of the metal-containing residue to be supplied to the biomass. ２ a catalyst mixing and preparation facility for mixing and preparing an oxygenated catalyst and the hydrogenation catalyst; ２ A bioethanol production apparatus comprising: a catalyst mixing amount adjusting means for adjusting the mixing amount of an oxygenated catalyst.

11. A gas separation facility that separates carbon dioxide from a mixed gas of hydrogen and carbon dioxide contained in the residual gas after separating the reaction gas generated in the bioethanol production facility from a liquid product containing ethanol; a first piping facility that supplies the carbon dioxide recovered in the gas separation facility to the reforming-gasification furnace; a carbon dioxide supply amount adjustment means that adjusts the amount of the recovered carbon dioxide supplied to the reforming-gasification furnace; a second piping facility that supplies residual hydrogen remaining in the gas separation facility to a hydrogen holder; a hydrogen supply amount adjustment means that adjusts the amount of the residual hydrogen supplied to the hydrogen holder; a third piping facility that supplies hydrogen generated in a water electrolysis facility to the hydrogen holder; a supply facility that supplies the residual hydrogen and the hydrogen from the hydrogen holder to the reforming-gasification furnace; a hydrogen supply amount adjustment means that adjusts the amount of the residual hydrogen and the hydrogen supplied to the reforming-gasification furnace; a pressurization and circulation supply facility that brings the reformed gas into contact with a composite catalyst; and a reformed gas circulation amount adjustment means that adjusts the amount of the reformed gas circulated to the composite catalyst. The bioethanol production apparatus according to claim 10, further comprising: a separation and purification facility that separates and purifies bioethanol from a liquid product containing ethanol.

12. A bioethanol production apparatus as described in claim 10 or 11, comprising: a combustion furnace that burns the dry distillation gas generated in the carbonization furnace; a heat exchanger that heats steam to be introduced into the reforming gasification furnace; piping equipment that supplies the combustion gas generated in the combustion furnace as heating gas to at least one of the reforming gasification furnace, the biomass dryer, the carbonization furnace, and the shift reaction equipment; a gas temperature adjustment means that adjusts the temperature of the gas; and a gas flow rate adjustment means that adjusts the flow rate of the gas.

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