ethanol

Abstract

We provide ethanol containing specific organic components. [Solution] The ethanol according to the present invention has an aliphatic hydrocarbon content of 0.16 mg / L or more and 10 mg / L or less.

Description

Technical Field

[0001] The present invention relates to ethanol, and more particularly to ethanol with the content of specific trace components adjusted. Further, the present invention relates to a novel resource-cycling ethanol using a gas containing carbon monoxide and hydrogen as a substrate, which is not derived from conventional petroleum resources or biomass resources.

Background Art

[0002] Petrochemical products are used in various aspects of our lives. On the other hand, because they are familiar products, the large-scale production and consumption have caused various environmental problems on a global scale, which has become a major issue. For example, polyethylene and polyvinyl chloride, which are representatives of petrochemical industrial products, are consumed in large quantities and discarded, and these wastes are a major cause of environmental pollution. In addition, concerns about the depletion of fossil fuel resources and global environmental problems such as the increase in carbon dioxide in the atmosphere are also being discussed in the large-scale production of petrochemical industrial products.

[0003] Due to the increasing global awareness of such environmental problems, in recent years, methods for producing various organic substances using raw materials other than naphtha, which is the raw material of petrochemical industrial products, have been studied. For example, a method for producing bioethanol by sugar fermentation from edible raw materials such as corn has attracted attention. However, the sugar fermentation method using such edible raw materials has been pointed out to have problems such as causing an increase in food prices because limited agricultural land is used for production other than food.

[0004] To address this problem, the use of non-edible raw materials that were previously discarded is being considered. Specifically, methods such as producing alcohols by fermentation using waste materials and cellulose derived from recycled paper as non-edible raw materials, or gasifying the aforementioned biomass raw materials and producing alcohols from the synthesis gas using a catalyst have been proposed, but none of these have yet been put into practical use. Furthermore, even if various petrochemical products could be manufactured from these de-petrification raw materials, they would ultimately become waste plastics that do not decompose naturally, and therefore cannot be considered an effective fundamental solution to environmental problems.

[0005] Incidentally, the amount of combustible waste currently discarded in Japan amounts to approximately 60 million tons per year. Its energy content is equivalent to approximately 200 trillion kilocalories, far exceeding the energy content of naphtha used as a raw material for plastics in Japan, and thus this waste can be considered a valuable resource. If these waste resources can be converted into petrochemical products, it will be possible to realize the ultimate resource-recycling society that does not rely on petroleum resources. From the above perspective, Patent Documents 1 and 2 disclose a technology for producing synthesis gas (a gas mainly composed of CO and H2) from waste, and then producing ethanol from that synthesis gas by fermentation.

[0006] However, as pointed out in Patent Document 3, synthesis gas produced from waste contains a wide variety of unidentified impurities, some of which are toxic to microorganisms. Therefore, productivity has been a major challenge in producing alcohol from synthesis gas through microbial fermentation. Furthermore, the alcohol obtained by microbial fermentation of synthesis gas also contains various components resulting from the impurities in the synthesis gas, and these components cannot be completely removed even by purification processes such as distillation. For this reason, developing derivative products from alcohol obtained by microbial fermentation of synthesis gas has been a major technical challenge. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2016-059296 [Patent Document 2] International Publication No. 2015-037710 [Patent Document 3] Japanese Patent Publication No. 2018-058042 [Overview of the project] [Problems that the invention aims to solve]

[0008] According to the inventors' research, while C2 raw materials, such as conventional ethanol, are known to be used as starting materials for various chemical products, as mentioned above, alcohol produced from resources other than petroleum or biomass resources (recyclable resources) contains various trace amounts of unknown substances, unlike chemical raw materials derived from naphtha. However, in conventional technology, the properties of these substances are unknown, and it has not been sufficiently investigated whether it is sufficient to remove all substances or only specific substances. Therefore, even though alcohol produced from recyclable resources has been proposed in the above-mentioned patent documents, there is still much room for technological improvement before such alcohol can be put into practical use.

[0009] On the other hand, while the above-mentioned literature discloses general fermentation and distillation methods and the optimal synthesis gas composition, it does not describe the details of the process, nor does it even identify the resulting alcoholic substance.

[0010] Therefore, the present invention has been made in view of the above background art, and its objective is to provide a novel alcohol and its derivatives that have industrial value compared to existing petrochemical raw materials and are practical. [Means for solving the problem]

[0011] The inventors of this invention conducted diligent research to solve the above problems and, as a result, identified a wide variety of trace substances contained in alcohol produced from recycled resources. Furthermore, they found that it is possible to control the content within a specific range using a novel manufacturing method, and that various derivatives thereof exhibit superior effects compared to existing petrochemical-derived alcohols. For example, in the process of synthesizing butadiene from ethanol, they found that the ethanol conversion rate was improved compared to when conventional petrochemical-derived ethanol was used, and that alcohol at a practical level equivalent to or better than petrochemical-derived alcohol could be obtained, leading to the present invention.

[0012] More specifically, we discovered that when ethanol is produced from a gas substrate containing carbon monoxide and hydrogen using waste as a carbon source, the conversion rate of ethanol improves when butadiene is synthesized from the ethanol. Upon investigating the reason for this in detail, we found that trace amounts of organic components are present in ethanol derived from recycled resources using gases containing carbon monoxide and hydrogen as substrates. This invention is based on these findings.

[0013] In other words, the present invention includes the following gist. [1] Ethanol having an aliphatic hydrocarbon content of 0.16 mg / L or more and 10 mg / L or less. [2] The ethanol described in [1], wherein the substrate is a gas containing carbon monoxide and hydrogen. [3] Ethanol as described in [1] or [2], derived from microbial fermentation. [4] The ethanol according to any one of [1] to [3], wherein the aliphatic hydrocarbon comprises at least one selected from the group consisting of n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane. [5] The ethanol according to [2], wherein the gas containing carbon monoxide and hydrogen is derived from waste. [6] A process of converting a carbon source into synthesis gas containing carbon monoxide and hydrogen, A microbial fermentation step involves supplying the aforementioned synthesis gas containing carbon monoxide and hydrogen to a microbial fermentation tank and obtaining an ethanol-containing liquid by microbial fermentation, A separation step is performed to separate the ethanol-containing liquid into a liquid or solid component containing microorganisms and a gaseous component containing ethanol. A liquefaction step in which the aforementioned gaseous component is condensed and liquefied, A purification step is performed to purify ethanol from the liquid obtained in the liquefaction step, Includes, A method for producing ethanol, wherein the aliphatic hydrocarbon content in the purified ethanol is 0.16 mg / L or more and 10 mg / L or less. [7] The method according to [6], further comprising the step of purifying the synthesis gas. [8] The method according to [6] or [7], wherein the carbon source is derived from waste. [9] Ethanol for chemical use, as described in any of [1] to [5].

[10] Ethanol for fuel purposes as described in any of [1] to [5].

[11] Ethanol for polymer raw materials, as described in any of [1] to [5].

[12] A chemical product made from ethanol as described in any of [1] to [5].

[13] A fuel comprising ethanol as described in any of [1] to [5] and / or ethyl-t-butyl ether derived from ethanol as described in any of [1] to [5].

[14] Polymer raw materials made from ethanol as described in any of [1] to [5].

[15] Polymer raw materials as described in

[14] , selected from the group consisting of ethylene, propylene, butadiene, ethyl acetate, isobutene, methyl (meth)acrylate, acrylic acid, aminohexanoic acid, and diethyl carbonate.

[16] A polymer made from the polymer raw materials described in

[14] or

[15] .

[17] A molded article made of the polymer described in

[16] . [Effects of the Invention]

[0014] According to the present invention, by using ethanol containing specific trace organic components, various different effects can be obtained compared to commercially available industrial ethanol. For example, according to the present invention, the ethanol conversion rate when synthesizing butadiene from ethanol as a raw material can be improved, the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids can be improved, and the combustion efficiency when using ethanol as a fuel can be improved. In addition, it is expected that the same effects can be obtained even with existing alcohols by containing a specific amount of specific organic components.

[0015] Also, the ethanol according to the present invention can be used, for example, as a raw material for the production of butadiene, ethylene, propylene, isobutene, acetaldehyde, acetic acid, ethyl acetate, methyl (meth)acrylate, ethyl-t-butyl ether ethylene glycol, ester compositions, polyesters, acrylic acid, aminohexanoic acid, diethyl carbonate, polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyisobutylene, polymethyl methacrylate (PMMA), ethylene propylene diene rubber (EPDM), polybutylene terephthalate (PBT), polyethylene furanoate (PEF), polyurethane (PU), etc. Further, the ethanol according to the present invention can be used for various applications of chemical products such as cosmetics, perfumes, fuels, antifreeze liquids, bactericides, disinfectants, cleaning agents, mold removers, detergents, shampoos, soaps, antiperspirants, facial cleansing sheets, solvents, paints, adhesives, diluents, food additives, etc.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, an example of a preferred embodiment for carrying out the present invention will be described. However, the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments in any way.

[0017] <Definition> In this invention, "ethanol" does not mean pure ethanol as a compound (ethanol represented by the chemical formula CH3CH2OH), but rather a composition containing impurities (contaminating components) that are inevitably present in ethanol produced through synthesis or purification.

[0018] <Ethanol> The total aliphatic hydrocarbon content in the ethanol according to the present invention is 0.16 mg / L or more and 10 mg / L or less. The aliphatic hydrocarbon is preferably a chain-type saturated hydrocarbon having 6 to 14 carbon atoms, such as n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane. Only one of these may be included, or two or more may be included.

[0019] The total amount of aliphatic hydrocarbons contained in ethanol is preferably 0.2 mg / L or more, more preferably 0.3 mg / L or more, even more preferably 0.4 mg / L or more, and preferably 7 mg / L or less, more preferably 5 mg / L or less, and even more preferably 3 mg / L or less, relative to the total amount of ethanol. Having the aliphatic hydrocarbon content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0020] When n-hexane is present in ethanol, the n-hexane content is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, even more preferably 0.3 mg / L or more, even more preferably 0.5 mg / L or more, and also preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and even more preferably 1 mg / L or less. Having the n-hexane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0021] When n-heptane is present in ethanol, the n-heptane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the n-heptane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0022] When n-octane is present in ethanol, the n-octane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the n-octane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0023] When n-decane is present in ethanol, the n-decane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the n-decane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0024] When n-dodecane is present in ethanol, the n-dodecane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the n-dodecane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0025] When n-tetradecane is present in ethanol, the n-tetradecane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the n-tetradecane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0026] When ethanol contains hexadecane, the hexadecane content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the hexadecane content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0027] The ethanol according to the present invention is preferably ethanol derived from a gas containing carbon monoxide and hydrogen as a substrate, or ethanol derived from microbial fermentation. This is because it is easy to incorporate aliphatic hydrocarbons at the above concentration in the manufacturing process if these types of ethanol are used. Here, ethanol with 100% purity, i.e., ethanol that contains no impurities at all, does not contain aliphatic hydrocarbons at the above concentration. Also, commercially available industrial ethanol derived from fossil fuels, or ethanol produced by fermentation using biomass raw materials such as cellulose, does not usually contain aliphatic hydrocarbons at the above concentration, but aliphatic hydrocarbons may be added to achieve the above concentration.

[0028] While not bound by theory, ethanol derived from microbial fermentation using gases containing carbon monoxide and hydrogen as substrates is thought to contain various trace components in addition to carbon monoxide and hydrogen in the synthesis gas used during its production process. Therefore, even alcohol obtained through purification processes such as distillation is difficult to completely remove impurities, and it is thought that organic substances inevitably remain in the alcohol. In the present invention, it is thought that the inclusion of these unavoidable substances in ethanol can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when ethanol is used as fuel.

[0029] The ethanol of the present invention is obtained by extracting and further purifying an ethanol-containing liquid obtained from a microbial fermentation tank, as described below. However, in addition to the unavoidable substances mentioned above, it may also contain other components as listed below. For example, it may contain trace amounts of aromatic compounds.

[0030] Aromatic compounds that can be contained in ethanol include toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene. Only one of these may be present, or two or more may be present. It is preferable that ethylbenzene is included as the aromatic compound.

[0031] The total amount of aromatic compounds contained in ethanol is preferably 0.4 mg / L or more, more preferably 0.5 mg / L or more, even more preferably 1.0 mg / L or more, and preferably 7 mg / L or less, more preferably 5 mg / L or less, and even more preferably 3 mg / L or less, relative to the total amount of ethanol. Having the aromatic compound content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0032] When ethylbenzene is present in ethanol, the ethylbenzene content is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, even more preferably 0.3 mg / L or more, even more preferably 0.5 mg / L or more, and also preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and even more preferably 1 mg / L or less, relative to the total ethanol. Having the ethylbenzene content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0033] When ethanol contains toluene, the toluene content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, even more preferably 0.05 mg / L or more, and also preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and even more preferably 0.1 mg / L or less. Having the toluene content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0034] When o-xylene is present in ethanol, the o-xylene content is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, even more preferably 0.3 mg / L or more, even more preferably 0.5 mg / L or more, and also preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and even more preferably 1 mg / L or less. Having the o-xylene content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0035] When ethanol contains m-xylene and / or p-xylene, the total content of m-xylene and / or p-xylene is preferably 0.2 mg / L or more, more preferably 0.3 mg / L or more, even more preferably 0.4 mg / L or more, even more preferably 0.5 mg / L or more, and also preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and even more preferably 1 mg / L or less. Having the content of m-xylene and / or p-xylene within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0036] Furthermore, the ethanol according to the present invention may further contain trace amounts of dialkyl ether. Examples of dialkyl ethers include dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, and dipentyl ether, and may contain only one of these or two or more. It is preferable that the dialkyl ether contains dibutyl ether.

[0037] The total amount of dialkyl ether contained in ethanol is preferably 0.001 mg / L or more, more preferably 0.01 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 1.0 mg / L or more, and 100 mg / L or less, more preferably 80 mg / L or less, more preferably 50 mg / L or less, and even more preferably 30 mg / L or less. Having the dialkyl ether content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0038] When dibutyl ether is present in ethanol, the dibutyl ether content is preferably 1 mg / L or more, more preferably 2 mg / L or more, even more preferably 5 mg / L or more, even more preferably 10 mg / L or more, and also preferably 50 mg / L or less, more preferably 40 mg / L or less, even more preferably 30 mg / L or less, and even more preferably 25 mg / L or less. Having the dibutyl ether content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0039] The ethanol of the present invention contains trace amounts of the organic compounds described above, but may also contain compounds containing elements such as Si, K, Na, Fe, and Cr. These element-containing compounds may be inorganic compounds or organometallic compounds. For example, when Si is included, silica or organosiloxanes may also be included.

[0040] When ethanol contains Si, the Si content is preferably 10 mg / L or more, more preferably 20 mg / L or more, even more preferably 30 mg / L or more, and also preferably 100 mg / L or less, more preferably 90 mg / L or less, and even more preferably 80 mg / L or less, relative to the ethanol. The Si content refers to the amount of Si element in the Si compound. Having the Si content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0041] When K is present in ethanol, the K content is preferably 1.0 mg / L or more, more preferably 1.5 mg / L or more, even more preferably 2.0 mg / L or more, even more preferably 2.5 mg / L or more, and also preferably 10 mg / L or less, more preferably 7 mg / L or less, and even more preferably 5 mg / L or less, relative to ethanol. The K content refers to the amount of K element in the K compound. Having the K content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0042] When ethanol contains sodium, the sodium content is preferably 150 mg / L or more, more preferably 170 mg / L or more, even more preferably 190 mg / L or more, and also preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 400 mg / L or less, and even more preferably 300 mg / L or less, relative to ethanol. The sodium content refers to the amount of sodium in the sodium compound. Having the sodium content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0043] When ethanol contains Fe, the Fe content is preferably 2.0 mg / L or less, more preferably 1.5 mg / L or less, even more preferably 1.0 mg / L or less, and even more preferably 0.5 mg / L or less, relative to ethanol. The Fe content refers to the amount of Fe element in the Fe compound. Having the Fe content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0044] When ethanol contains Cr, the Cr content is preferably 0.6 mg / L or less, and more preferably 0.5 mg / L or less, relative to the ethanol. The Cr content refers to the amount of Cr in the Cr compound on an elemental basis. Having the Cr content within the above numerical range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and improve the combustion efficiency when using ethanol as fuel.

[0045] The ethanol of the present invention contains the inorganic components described above, and optionally trace amounts of organic components such as aromatic hydrocarbons and aliphatic hydrocarbons. The concentration of ethanol (pure ethanol as a compound), which is the main component of the ethanol, is 75% by volume or more, preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, even more preferably 98% by volume or more, and also preferably 99.999% by volume or less, more preferably 99.99% by volume or less, even more preferably 99.9% by volume or less, and even more preferably 99.5% by volume or less.

[0046] The ethanol concentration in the ethanol of this invention can be set according to the intended use. For example, a concentration of 90% by volume or higher is preferred for cosmetics, and 75% by volume or higher is preferred for disinfectant ethanol. The upper limit can also be conveniently set according to the application. From the perspective of transportation costs, a higher ethanol concentration is preferable for the final product.

[0047] <Method for producing ethanol> One method for producing ethanol with the characteristic gas chromatographic peaks described above is to produce ethanol by microbial fermentation of synthesis gas containing carbon monoxide derived from waste or exhaust gas. In such a method, the content of aromatic compounds in the raw material gas derived from waste or exhaust gas and the purification conditions may be controlled to control the amount of aromatic compounds in the final product. Below, as an example, a method for producing ethanol by microbial fermentation of synthesis gas containing carbon monoxide derived from waste or exhaust gas will be described.

[0048] The method for producing ethanol includes the steps of: converting a carbon source into synthesis gas containing carbon monoxide and hydrogen; supplying the synthesis gas containing carbon monoxide and hydrogen to a microbial fermentation tank to obtain an ethanol-containing liquid by microbial fermentation; separating the ethanol-containing liquid into a liquid or solid component containing microorganisms and a gaseous component containing ethanol; liquefaction, condensing the gaseous component into a liquid; and purification, purifying the ethanol from the liquid obtained in the liquefaction step. However, it may also include, if necessary, a raw material gas generation step, a synthesis gas preparation step, a wastewater treatment step, etc. Each step will be described below.

[0049] <Raw material gas generation process> The raw material gas generation process is a process in which raw material gas is generated in the gasification section by gasifying a carbon source. A gasification furnace may be used in the raw material gas generation process. A gasification furnace is a furnace that burns (incompletely combusts) a carbon source, and examples include shaft furnaces, kiln furnaces, fluidized bed furnaces, and gasification reforming furnaces. A fluidized bed furnace is preferred for the gasification furnace because it allows for high hearth load and excellent operability by partially burning the waste. By gasifying the waste in a fluidized bed furnace at a low temperature (approximately 450-600°C) and a low-oxygen atmosphere, it is decomposed into gases (carbon monoxide, carbon dioxide, hydrogen, methane, etc.) and char containing a large amount of carbon. Furthermore, since non-combustible materials contained in the waste are separated from the bottom of the furnace in a hygienic and low-oxidation state, it is possible to selectively recover valuable materials such as iron and aluminum from the non-combustible materials. Therefore, such gasification of waste enables efficient resource recycling.

[0050] The temperature of the gasification process in the raw material gas generation process is not particularly limited, but is usually 100 to 2500°C, and preferably 200 to 2100°C.

[0051] The reaction time for gasification in the raw material gas generation process is usually 2 seconds or more, preferably 5 seconds or more.

[0052] The carbon sources used in the raw material gas generation process are not particularly limited, and various carbon-containing materials can be suitably used for recycling purposes, such as coke ovens and blast furnaces (blast furnace gas) in steel mills, coal used in converters and coal-fired power plants, general waste and industrial waste introduced into incinerators (especially gasifiers), and carbon dioxide produced as a by-product by various industries.

[0053] More specifically, carbon sources are preferably waste materials, including plastic waste, food waste, municipal solid waste (MSW), industrial solid waste, discarded tires, biomass waste, household waste such as bedding and paper, building materials, coal, petroleum, petroleum-derived compounds, natural gas, and shale gas. Among these, various types of waste are preferred, and from the perspective of sorting costs, unsorted municipal solid waste is even more preferred.

[0054] The raw material gas obtained by gasifying a carbon source contains carbon monoxide and hydrogen as essential components, but may also contain carbon dioxide, oxygen, and nitrogen. Other components that may be included in the raw material gas include soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, and aromatic compounds.

[0055] The raw material gas may be produced in the raw material gas production process by performing a heat treatment (commonly known as gasification) that burns (incompletely burns) the carbon source, that is, by partially oxidizing the carbon source, resulting in a gas containing carbon monoxide, although not particularly limited, 0.1 volume% or more, preferably 10 volume% or more, and more preferably 20 volume% or more.

[0056] <Synthesis gas purification process> The synthesis gas purification process is a process of removing or reducing specific substances such as various pollutants, particulate matter, impurities, and undesirable amounts of compounds from the raw gas. When the raw gas is derived from waste, it typically contains 0.1% to 80% by volume of carbon monoxide, 0.1% to 70% by volume of carbon dioxide, and 0.1% to 80% by volume of hydrogen, and also tends to contain 1 mg / L or more of nitrogen compounds, 1 mg / L or more of sulfur compounds, 0.1 mg / L or more of phosphorus compounds, and / or 10 mg / L or more of aromatic compounds. In addition, other environmental pollutants, particulate matter, and impurities may also be present. Therefore, when supplying synthesis gas to a microbial fermentation tank, it is preferable to reduce or remove substances undesirable for the stable cultivation of microorganisms, or undesirable amounts of compounds, from the raw material gas, so that the content of each component in the raw material gas is within a range suitable for the stable cultivation of microorganisms.

[0057] In particular, in the synthesis gas purification process, a pressure swing adsorption device filled with the above-mentioned regenerative adsorbent is used to adsorb carbon dioxide gas in the synthesis gas onto the regenerative adsorbent (zeolite), thereby reducing the carbon dioxide gas concentration in the synthesis gas. Furthermore, the synthesis gas may be subjected to other conventionally known treatment processes to remove impurities and adjust the gas composition. Other treatment processes include, for example, gas chillers (moisture separators), cryogenic separators, cyclones, particulate matter (soot) separators such as bag filters, scrubbers (water-soluble impurity separators), desulfurization devices (sulfide separators), membrane separators, deoxygenation devices, pressure swing adsorption (PSA), temperature swing adsorption (TSA), pressure-temperature swing adsorption (PTSA), activated carbon separators, and deoxygenation catalysts, specifically, separators using copper catalysts or palladium catalysts, one or more of which can be used for treatment.

[0058] The synthesis gas used in the ethanol production method of the present invention contains at least carbon monoxide as an essential component, and may further contain hydrogen, carbon dioxide, and nitrogen.

[0059] The synthesis gas used in the present invention may be obtained by first generating a raw material gas by gasifying a carbon source (raw material gas generation step), and then by adjusting the concentrations of carbon monoxide, carbon dioxide, hydrogen, and nitrogen from the raw material gas, as well as by reducing or removing the above-mentioned substances and compounds.

[0060] The carbon monoxide concentration in the synthesis gas is typically 20% to 80% by volume, preferably 25% to 50% by volume, and more preferably 35% to 45% by volume, relative to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0061] The hydrogen concentration in the synthesis gas is typically 10% to 80% by volume, preferably 30% to 55% by volume, and more preferably 40% to 50% by volume, relative to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0062] The carbon dioxide concentration in the synthesis gas is typically 0.1% to 40% by volume, preferably 0.3% to 30% by volume, more preferably 0.5% to 10% by volume, and particularly preferably 1% to 6% by volume, relative to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0063] The nitrogen concentration in the synthesis gas is typically 40% by volume or less, preferably 1% to 20% by volume, and more preferably 5% to 15% by volume, relative to the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0064] The concentrations of carbon monoxide, carbon dioxide, hydrogen, and nitrogen can be kept within a predetermined range by changing the elemental composition of hydrocarbons (carbon and hydrogen) and nitrogen in the raw material gas production process, or by appropriately changing combustion conditions such as combustion temperature and oxygen concentration of the gas supplied during combustion. For example, if you want to change the carbon monoxide or hydrogen concentration, you can switch to a carbon source with a high ratio of hydrocarbons (carbon and hydrogen), such as waste plastics. If you want to lower the nitrogen concentration, you can supply a gas with a high oxygen concentration in the raw material gas production process.

[0065] The synthesis gas used in the present invention is not particularly limited in that it contains sulfur compounds, phosphorus compounds, nitrogen compounds, etc., in addition to the components described above. The content of each of these compounds is preferably 0.05 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 0.5 mg / L or more, and also preferably 2000 mg / L or less, more preferably 1000 mg / L or less, even more preferably 80 mg / L or less, even more preferably 60 mg / L or less, and particularly preferably 40 mg / L or less. By setting the content of sulfur compounds, phosphorus compounds, nitrogen compounds, etc. above the lower limit, there is the advantage that microorganisms can be cultured suitably, and by setting the content below the upper limit, there is the advantage that the culture medium is not contaminated by various nutrients that were not consumed by the microorganisms.

[0066] Examples of sulfur compounds include sulfur dioxide, CS2, COS, and H2S, with H2S and sulfur dioxide being preferred because they are easily consumed as nutrients by microorganisms. Therefore, it is more preferable that the sum of H2S and sulfur dioxide in the synthesis gas is within the above range. As a phosphorus compound, phosphate is preferred because it is readily consumed as a nutrient source by microorganisms. Therefore, it is more preferable that the synthesis gas contains phosphate within the above range. Examples of nitrogen compounds include nitric oxide, nitrogen dioxide, acrylonitrile, acetonitrile, and HCN, with HCN being preferred because it is easily consumed as a nutrient source by microorganisms. Therefore, it is more preferable that the synthesis gas contains HCN within the above range.

[0067] Furthermore, the synthesis gas may contain aromatic compounds in an amount of 0.01 mg / L to 90 mg / L, preferably 0.03 mg / L or more, more preferably 0.05 mg / L or more, even more preferably 0.1 mg / L or more, and preferably 70 mg / L or less, more preferably 50 mg / L or less, and even more preferably 30 mg / L or less. By setting the content above the lower limit, microorganisms tend to be able to be cultured suitably, and by setting the content below the upper limit, the culture medium tends to be less contaminated by various nutrients that were not consumed by the microorganisms.

[0068] <Microbial fermentation process> The microbial fermentation process involves producing ethanol by microbial fermentation of the above-mentioned synthesis gas in a microbial fermentation tank. It is preferable that the microbial fermentation tank be a continuous fermentation apparatus. In general, microbial fermentation tanks can be of any shape, including agitated type, air-lift type, bubble tower type, loop type, open bond type, and photobio type. However, in the present invention, a known loop reactor having a main tank section and a reflux section can be suitably used as the microbial fermentation tank. In this case, it is preferable to further include a circulation step in which the liquid culture medium is circulated between the main tank section and the reflux section.

[0069] The synthesis gas supplied to the microbial fermentation tank may be the gas obtained through the raw material gas production process, as long as it satisfies the above-mentioned synthesis gas component conditions, or it may be the raw material gas from which impurities have been reduced or removed, to which another predetermined gas is added before using as synthesis gas. As the other predetermined gas, for example, at least one compound selected from the group consisting of sulfur compounds such as sulfur dioxide, phosphorus compounds, and nitrogen compounds may be added to form the synthesis gas.

[0070] A microbial fermenter may be continuously supplied with synthesis gas and microbial culture medium, but it is not necessary to supply them simultaneously. Alternatively, synthesis gas may be supplied to a microbial fermenter that has already been supplied with microbial culture medium. Certain anaerobic microorganisms are known to produce ethanol and other substances from substrate gases such as synthesis gas through fermentation, and these gas-assimilating microorganisms are cultured in liquid culture media. For example, a liquid culture medium and gas-assimilating bacteria may be supplied and contained within the microbial fermenter, and synthesis gas may be supplied to the microbial fermenter while stirring the liquid culture medium. This allows gas-assimilating bacteria to be cultured in liquid culture media and to produce ethanol from synthesis gas through fermentation.

[0071] In a microbial fermentation tank, the temperature of the culture medium (culture temperature) can be any temperature, but it is preferably around 30-45°C, more preferably around 33-42°C, and even more preferably around 36.5-37.5°C. The culture time is preferably 12 hours or more for continuous culture, more preferably 7 days or more, particularly preferably 30 days or more, and most preferably 60 days or more. There is no upper limit, but from the viewpoint of equipment maintenance, it is preferably 720 days or less, and more preferably 365 days or less. The culture time refers to the time from when the starter culture is added to the culture tank until the entire amount of culture solution in the culture tank is drained.

[0072] The microorganisms (species) contained in the microbial culture solution are not particularly limited, as long as they can produce ethanol by microbial fermentation of synthesis gas using carbon monoxide as the main raw material. For example, the microorganism (species) is preferably one that produces ethanol from synthesis gas through the fermentation action of gas-utilizing bacteria, and is particularly preferably a microorganism that has an acetyl-COA metabolic pathway. Among gas-utilizing bacteria, the genus Clostridium is more preferred, and Clostridium autoetanogenum is particularly preferred, but is not limited thereto. Further examples are given below.

[0073] Gas-assimilating bacteria include both eubacteria and archaea. Examples of eubacteria include bacteria of the genera Clostridium, Moorella, Acetobacterium, Carboxydocella, Rhodopseudomonas, Eubacterium, Butyribacterium, Oligotropha, Bradyrhizobium, and the aerobic hydrogen-oxidizing bacteria Ralsotonia.

[0074] On the other hand, examples of archaea include bacteria of the genus Methanobacterium, bacteria of the genus Methanobrevibacter, bacteria of the genus Methanocalculus, bacteria of the genus Methanococcus, bacteria of the genus Methanosarcina, bacteria of the genus Methanosphaera, bacteria of the genus Methanothermobacter, Metha Examples include bacteria of the genus Nothrix, bacteria of the genus Methanoculleus, bacteria of the genus Methanofollis, bacteria of the genus Methanogenium, bacteria of the genus Methanospirillium, bacteria of the genus Methanosaeta, bacteria of the genus Thermococcus, bacteria of the genus Thermofilum, bacteria of the genus Arcaheoglobus, and the like. Among these, as archaea, bacteria of the genus Methanosarcina, bacteria of the genus Methanococcus, bacteria of the genus Methanothermobacter, bacteria of the genus Methanothrix, bacteria of the genus Thermococcus, bacteria of the genus Thermofilum, and bacteria of the genus Archaeoglobus are preferred.

[0075] Furthermore, due to their excellent assimilation capabilities of carbon monoxide and carbon dioxide, archaeons of the genera Methanosarcina, Methanothermobacter, or Methanococcus are preferred, with Methanosarcina or Methanococcus being particularly preferred. Specific examples of Methanosarcina bacteria include Methanosarcina barkeri, Methanosarcina mazei, and Methanosarcina acetivorans.

[0076] From among the gas-assimilating bacteria described above, bacteria with high ethanol production capacity are selected and used. For example, gas-assimilating bacteria with high ethanol production capacity include Clostridium autoethanogenum, Clostridium ljungdahlii, Clostridium aceticum, Clostridium carboxidivorans, Moorella thermoacetica, and Acetobacterium woodii, among which Clostridium autoethanogenum is particularly preferred.

[0077] The culture medium used when culturing the above-mentioned microorganisms (species) is not particularly limited as long as it has an appropriate composition for the bacteria, but it is a liquid containing water as the main component and nutrients (e.g., vitamins, phosphoric acid, etc.) dissolved or dispersed in this water. The composition of such a culture medium is prepared so that gas-assimilating bacteria can grow well. For example, when using Clostridium species as the microorganism, the culture medium can be referenced from "0097" to "0099" of U.S. Patent Application Publication 2017 / 260552.

[0078] The ethanol-containing liquid obtained through the microbial fermentation process can be obtained as a suspension containing microorganisms, their remains, and microbial-derived proteins. The protein concentration in the suspension varies depending on the type of microorganism, but is usually between 30 and 1000 mg / L. The protein concentration in the ethanol-containing liquid can be measured using the Kjeldahl method.

[0079] <Separation process> The ethanol-containing liquid obtained from the microbial fermentation process is then subjected to a separation process. In this invention, the ethanol-containing liquid is heated to room temperature to 500°C under conditions of 0.01 to 1000 kPa (absolute pressure) to separate it into a liquid or solid component containing microorganisms and a gaseous component containing ethanol. In conventional methods, the ethanol-containing liquid obtained from the microbial fermentation process was distilled to separate and purify the desired ethanol. However, since the ethanol-containing liquid contains microorganisms and proteins derived from microorganisms, distilling the ethanol-containing liquid as is could cause foaming in the distillation apparatus, hindering continuous operation. Furthermore, while membrane evaporators are known to be used as a method for purifying foaming liquids, membrane evaporators have low concentration efficiency and are not suitable for purifying liquids containing solid components. In this invention, before separating and purifying the desired ethanol from the ethanol-containing liquid obtained from the microbial fermentation process by distillation or other means, the ethanol-containing liquid is heated to separate it into a liquid or solid component containing microorganisms and a gaseous component containing ethanol, and the desired ethanol is separated and purified only from the separated gaseous component containing ethanol. By implementing the separation process, foaming is prevented in the distillation apparatus during the distillation operation for the separation and purification of ethanol, allowing for continuous distillation. Furthermore, since the concentration of ethanol in the gaseous component containing ethanol is higher than the concentration of ethanol in the ethanol-containing liquid, the separation and purification of ethanol can be performed efficiently in the purification process described later.

[0080] In the present invention, from the viewpoint of efficiently separating a liquid or solid component containing microorganisms, their remains, microbial-derived proteins, etc., from a gaseous component containing ethanol, the ethanol-containing liquid is heated preferably under conditions of 10 to 200 kPa, more preferably under conditions of 50 to 150 kPa, even more preferably under atmospheric pressure, at a temperature of preferably 50 to 200°C, more preferably 80 to 180°C, and even more preferably 100 to 150°C.

[0081] The heating time in the separation process is not particularly limited as long as it is sufficient to obtain the gaseous component, but from the viewpoint of efficiency or economy, it is usually 5 seconds to 2 hours, preferably 5 seconds to 1 hour, and more preferably 5 seconds to 30 minutes.

[0082] The separation process described above can be carried out without particular limitations, as long as it is an apparatus capable of efficiently separating an ethanol-containing liquid into liquid or solid components (microorganisms and their remains, proteins derived from microorganisms, etc.) and gaseous components (ethanol) using thermal energy. For example, drying apparatuses such as rotary dryers, fluidized bed dryers, vacuum dryers, and conduction-type dryers can be used. However, from the viewpoint of efficiency when separating an ethanol-containing liquid with a low solid component concentration into liquid or solid components and gaseous components, it is preferable to use a conduction-type dryer. Examples of conduction-type dryers include drum-type dryers and disc-type dryers.

[0083] <Liquefaction process> The liquefaction step is a process of liquefying the gaseous component containing ethanol obtained in the separation step by condensation. The apparatus used in the liquefaction step is not particularly limited, but it is preferable to use a heat exchanger, especially a condenser. Examples of condensers include water-cooled, air-cooled, and evaporative types, with water-cooled condensers being preferred among them. The condenser may consist of one stage or multiple stages.

[0084] It is preferable that the liquefied product obtained by the liquefaction process does not contain components that were present in the ethanol-containing solution, such as microorganisms, their remains, and proteins derived from microorganisms. However, the present invention does not exclude the possibility of proteins being present in the liquefied product. Even if proteins are present in the liquefied product, their concentration is preferably 40 mg / L or less, more preferably 20 mg / L or less, and even more preferably 15 mg / L or less.

[0085] The heat of condensation of the gaseous components obtained by the condenser may be reused as a heat source in the purification process described later. By reusing the heat of condensation, ethanol can be produced efficiently and economically.

[0086] <Purification process> Next, ethanol is purified from the liquefied product obtained in the liquefaction step. The ethanol-containing liquid obtained in the microbial fermentation step can be supplied to the purification step without going through the separation step described above if components such as microorganisms have already been removed. The purification step is a process of separating the ethanol-containing liquid obtained in the liquefaction step into a distillate with a higher concentration of the target ethanol and a bottom-extracted liquid with a lower concentration of the target ethanol. Examples of equipment used in the purification step include distillation apparatus, processing apparatus including permeable vaporization membrane, processing apparatus including zeolite dehydration membrane, processing apparatus for removing low-boiling-point substances with a boiling point lower than ethanol, processing apparatus for removing high-boiling-point substances with a boiling point higher than ethanol, and processing apparatus including ion exchange membrane. These apparatuses may be used individually or in combination of two or more types. As unit operations, heating distillation or membrane separation may be suitably used.

[0087] In heated distillation, the desired ethanol can be obtained as a distillate with high purity using a distillation apparatus. The temperature inside the distillation apparatus during ethanol distillation is not particularly limited, but it is preferably 100°C or lower, and more preferably around 70-95°C. By setting the temperature inside the distillation apparatus within the above range, the separation of ethanol from other components, i.e., the distillation of ethanol, can be performed more reliably.

[0088] In particular, by introducing the ethanol-containing liquid obtained in the liquefaction process into a distillation apparatus equipped with a heater using steam at 100°C or higher, raising the temperature at the bottom of the distillation column to 90°C or higher within 30 minutes, then introducing the ethanol-containing liquid from the middle of the distillation column, and performing the distillation process while the temperature difference between the bottom, middle, and top of the column is within ±15°C, high-purity ethanol can be obtained. The distillation temperature difference is preferably ±13°C, and more preferably ±11°C. With the above distillation temperature difference, separation from other components, i.e., distillation of ethanol, can be performed more reliably.

[0089] The ethanol-containing liquid described above is thought to contain aliphatic hydrocarbons with a boiling point higher than ethanol (e.g., heptane, octane, decane, dodecane, tetradecane, etc.). In this invention, by adjusting the above-mentioned distillation conditions, for example, by raising the temperature at the top of the distillation column to 5 to 10°C higher than usual, aromatic compounds can also be distilled off, thereby adjusting the amount of aromatic compounds in the ethanol contained in the distillate. As a result, the final content of aromatic compounds in the ethanol can be adjusted.

[0090] The pressure inside the distillation apparatus during ethanol distillation may be atmospheric pressure, but is preferably less than atmospheric pressure, and more preferably around 60 to 95 kPa (absolute pressure). By setting the pressure inside the distillation apparatus within the above range, the separation efficiency of ethanol can be improved, and consequently, the yield of ethanol can be improved. The yield of ethanol (the concentration of ethanol contained in the distillate after distillation) is preferably 90% by volume or more, and more preferably 95% by volume or more.

[0091] In membrane separation, known separation membranes can be used as appropriate, and for example, zeolite membranes can be suitably used.

[0092] The concentration of ethanol in the distillate separated in the purification process is preferably 20% to 99.99% by volume, and more preferably 60% to 99.9% by volume. On the other hand, the concentration of ethanol in the canned liquid is preferably 0.001% to 10% by volume, and more preferably 0.01% to 5% by volume.

[0093] The bottom liquid separated in the purification process is substantially free of nitrogen compounds. In this invention, "substantially free" does not mean that the concentration of nitrogen compounds is 0 mg / L, but rather that the nitrogen compound concentration in the bottom liquid obtained in the purification process is such that a wastewater treatment process is not required. In the separation process, instead of purifying the desired ethanol from the ethanol-containing liquid obtained in the microbial fermentation process, the ethanol-containing liquid is separated into a liquid or solid component containing microorganisms and a gaseous component containing ethanol, as described above. At this time, the nitrogen compounds remain on the liquid or solid component side containing microorganisms, so the gaseous component containing ethanol contains almost no nitrogen compounds. Therefore, it is considered that the bottom liquid obtained when purifying ethanol from the liquefied product obtained by liquefying the gaseous component is substantially free of nitrogen compounds. Even if the bottom liquid contains nitrogen compounds, the concentration of nitrogen compounds is 0.1 to 200 mg / L, preferably 0.1 to 100 mg / L, and more preferably 0.1 to 50 mg / L.

[0094] Furthermore, for the same reasons as above, the bottom liquid separated in the purification process is substantially free of phosphorus compounds. Note that "substantially free" does not mean that the concentration of phosphorus compounds is 0 mg / L, but rather that the phosphorus compound concentration in the bottom liquid obtained in the purification process is low enough that a wastewater treatment process is not required. Even if the bottom liquid contains phosphorus compounds, the concentration of phosphorus compounds is 0.1 to 100 mg / L, preferably 0.1 to 50 mg / L, and more preferably 0.1 to 25 mg / L. Thus, according to the method of the present invention, the bottom liquid discharged in the ethanol purification process is substantially free of nitrogen compounds and phosphorus compounds, and is considered to contain almost no other organic matter, thus simplifying the wastewater treatment process that was conventionally required.

[0095] <Wastewater Treatment Process> The bottom liquid separated in the purification process may be supplied to the wastewater treatment process. In the wastewater treatment process, organic matter such as nitrogen compounds and phosphorus compounds can be further removed from the bottom liquid. In this process, organic matter may be removed by anaerobic or aerobic treatment of the bottom liquid. The removed organic matter may be used as fuel (heat source) in the refining process.

[0096] The treatment temperature in the wastewater treatment process is usually 0 to 90°C, preferably 20 to 40°C, and more preferably 30 to 40°C.

[0097] The bottom liquid obtained through the separation process has had liquid or solid components, including microorganisms, removed, thus reducing the burden of wastewater treatment and other processes compared to bottom liquid obtained by directly supplying it from the microbial fermentation process to the purification process.

[0098] In the wastewater treatment process, the concentration of nitrogen compounds in the treated liquid obtained by treating the bottom effluent is preferably 0.1 to 30 mg / L, more preferably 0.1 to 20 mg / L, and even more preferably 0.1 to 10 mg / L, and it is particularly preferable that no nitrogen compounds are present. Furthermore, the concentration of phosphorus compounds in the treated liquid is preferably 0.1 to 10 mg / L, more preferably 0.1 to 5 mg / L, and even more preferably 0.1 to 1 mg / L, and it is particularly preferable that no phosphorus compounds are present in the bottom effluent.

[0099] <Uses of ethanol> The ethanol according to the present invention can be used as a raw material for the production of various organic compounds. For example, the ethanol according to the present invention can be used as a raw material for the production of butadiene, ethylene, propylene, isobutene, acetaldehyde, acetic acid, ethyl acetate, methyl (meth)acrylate, ethyl-t-butyl ether ethylene glycol, ester compositions, polyesters, acrylic acid, aminohexanoic acid, diethyl carbonate, polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyisobutylene, polymethyl methacrylate (PMMA), ethylene propylene diene rubber (EPDM), polybutylene terephthalate (PBT), polyethylene furanoate (PEF), polyurethane (PU), and the like. Below, a method for synthesizing butadiene using the ethanol of the present invention as a raw material, as well as a method for producing polyethylene and polyester, will be described as an example, but it goes without saying that it can also be used as a raw material for other chemical products and polymers.

[0100] <Method for synthesizing butadiene> Butadiene is mainly produced by refining the C4 fraction, a by-product of ethylene synthesis from petroleum (i.e., naphtha cracking), and is a raw material for synthetic rubber. However, in recent years, there has been a strong demand for technologies to convert ethanol that is not derived from fossil fuels (ethanol derived from microbial fermentation) into 1,3-butadiene, as an alternative to chemical industrial raw materials obtained from petroleum. Methods for synthesizing butadiene using ethanol derived from microbial fermentation as a raw material include methods using MgO as a catalyst, methods using a mixture of Al2O3 and ZnO, and catalysts having a magnesium silicate structure. In addition to those mentioned above, vanadium, manganese, iron, cobalt, nickel, copper, zinc, gallium, niobium, silver, indium, and cerium are also used as catalysts.

[0101] By contacting the ethanol of the present invention with the catalyst described above and heating it, an ethanol conversion reaction occurs, and 1,3-butadiene can be synthesized. By synthesizing butadiene using the ethanol of the present invention as a raw material, it becomes possible to realize the ultimate resource-recycling society that does not rely on petroleum resources.

[0102] The heating temperature required to carry out the conversion reaction is, for example, 300 to 450°C, preferably 350 to 400°C, within the reaction system. If the temperature within the reaction system falls below this range, sufficient catalytic activity cannot be obtained, the reaction rate decreases, and the production efficiency tends to decline. On the other hand, if the temperature within the reaction system exceeds this range, the catalyst may deteriorate easily.

[0103] The reaction can be carried out by conventional methods such as batch, semi-batch, or continuous reactions. While batch or semi-batch reactions can increase the ethanol conversion rate, the ethanol produced according to the present invention can be converted more efficiently than conventional methods, even when using a continuous reaction. Although the reason for this is unclear, it is thought to be due to the presence of unique peaks in the gas chromatograph, measured by gas chromatography-mass spectrometry, that are not observed in ethanol derived from fossil fuels, in ethanol derived from recycled resources using gas containing carbon monoxide and hydrogen as a substrate, as in the present invention.

[0104] Methods for bringing the raw materials into contact with the catalyst include, for example, a suspension bed method, a fluidized bed method, and a fixed bed method. Furthermore, either a gas-phase or liquid-phase method may be used. For ease of catalyst recovery and regeneration, it is preferable to use a fixed-bed gas-phase continuous flow reactor in which the catalyst is packed into a reaction tube to form a catalyst layer, and the raw materials are flowed as a gas to react in the gas phase. When the reaction is carried out in the gas phase, the ethanol of the present invention may be gasified and supplied to the reactor without dilution, or it may be appropriately diluted with an inert gas such as nitrogen, helium, argon, or carbon dioxide before being supplied to the reactor.

[0105] After the ethanol conversion reaction is complete, the reaction product (1,3-butadiene) can be separated and purified by separation methods such as filtration, concentration, distillation, extraction, or a combination thereof.

[0106] <Polyethylene> The ethanol according to the present invention can also be suitably used as a raw material for polyethylene, which is widely used as a general-purpose plastic. Conventional polyethylene was produced by synthesizing ethylene from petroleum and polymerizing ethylene monomer. By producing polyethylene using the ethanol of the present invention, it becomes possible to realize the ultimate resource-recycling society that does not rely on petroleum resources.

[0107] First, ethylene, a raw material for polyethylene, is synthesized using ethanol according to the present invention as a raw material. The method for producing ethylene is not particularly limited and can be obtained by conventionally known methods, for example, by the dehydration reaction of ethanol. When obtaining ethylene by the dehydration reaction of ethanol, a catalyst is usually used, but this catalyst is not particularly limited and conventionally known catalysts can be used. A fixed-bed flow reaction, in which the separation of the catalyst and product is easy, is advantageous in terms of the process, and for example, γ-alumina is preferred.

[0108] Since the dehydration reaction is an endothermic reaction, it is usually carried out under heating conditions. The heating temperature is not limited as long as the reaction proceeds at a commercially useful rate, but a temperature of 100°C or higher is preferably appropriate, more preferably 250°C or higher, and even more preferably 300°C or higher. There is no particular upper limit, but from the viewpoint of energy balance and equipment, it is preferably 500°C or lower, more preferably 400°C or lower.

[0109] The reaction pressure is not particularly limited, but a pressure above atmospheric pressure is preferred to facilitate subsequent gas-liquid separation. Industrially, a fixed-bed flow reaction is preferred because it facilitates catalyst separation, but a liquid-phase suspension bed, fluidized bed, etc., may also be used.

[0110] In the dehydration reaction of ethanol, the yield of the reaction depends on the amount of water contained in the ethanol supplied as a raw material. Generally, when performing a dehydration reaction, it is preferable to have no water present in order to improve the efficiency of water removal. However, in the case of the dehydration reaction of ethanol using a solid catalyst, the absence of water tends to increase the amount of other olefins, especially butene. The lower limit of the acceptable water content is 0.1% by mass or more, preferably 0.5% by mass or more. The upper limit is not particularly limited, but from the viewpoint of mass balance and heat balance, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0111] As described above, the dehydration reaction of ethanol yields a mixture of ethylene, water, and a small amount of unreacted ethanol. Since ethylene is a gas at room temperature and pressures below approximately 5 MPa, water and ethanol can be removed from this mixture by gas-liquid separation to obtain ethylene. This can be done using any known method. Subsequently, the ethylene obtained by gas-liquid separation is further distilled. The distillation method, operating temperature, and residence time are not particularly restricted, except that the operating pressure at this time is above atmospheric pressure.

[0112] Ethanol derived from recycled resources using carbon monoxide and hydrogen-containing gases as substrates, as in the present invention, exhibits a unique peak in gas chromatography measured by gas chromatography-mass spectrometry that is not found in ethanol derived from fossil fuels. Therefore, it is believed that ethylene obtained from ethanol contains trace amounts of impurities. Depending on the application of ethylene, these trace amounts of impurities may be problematic and may be removed by purification. The purification method is not particularly limited and can be carried out by conventionally known methods. A suitable purification operation is, for example, adsorption purification. The adsorbent used is not particularly limited and can be a conventionally known adsorbent. For example, caustic water treatment may be used in combination as a method for purifying impurities in ethylene. If caustic water treatment is performed, it is desirable to perform it before adsorption purification. In that case, it is necessary to remove moisture after the caustic treatment and before adsorption purification.

[0113] The polymerization method for monomers containing ethylene is not particularly limited and can be carried out by conventionally known methods. The polymerization temperature and polymerization pressure should be adjusted as appropriate depending on the polymerization method and polymerization apparatus. The polymerization apparatus is also not particularly limited and can be conventionally known apparatus. An example of a polymerization method for monomers containing ethylene is described below.

[0114] The polymerization method for polyolefins, particularly ethylene polymers and copolymers of ethylene and α-olefins, can be appropriately selected depending on the type of polyethylene to be used, such as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), depending on differences in density and branching. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as the polymerization catalyst, and to carry out the polymerization in one or more stages using one of the following methods: gas-phase polymerization, slurry polymerization, solution polymerization, or high-pressure ionic polymerization.

[0115] The single-site catalyst described above is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a non-metallocene transition metal compound with an activation co-catalyst. Single-site catalysts are preferred over multi-site catalysts because they have a more uniform active site structure, allowing for the polymerization of polymers with high molecular weight and high uniformity. As a single-site catalyst, metallocene catalysts are particularly preferred. A metallocene catalyst is a catalyst comprising a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a co-catalyst, an organometallic compound if necessary, and each catalytic component of a support.

[0116] In a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, etc. The substituted cyclopentadienyl group has substituents such as hydrocarbon groups having 1 to 30 carbon atoms. Examples of transition metals include zirconium, titanium, and hafnium, with zirconium and hafnium being particularly preferred. The transition metal compound typically has two ligands having a cyclopentadienyl skeleton, and it is preferable that each ligand having a cyclopentadienyl skeleton is bonded to each other by a bridging group. The above-mentioned transition metal compounds can be used as catalyst components, either individually or as a mixture of two or more.

[0117] Co-catalysts are those that can effectively utilize the transition metal compounds mentioned above as polymerization catalysts, or that can balance the ionic charge of the catalytically activated state. Examples of co-catalysts include benzene-soluble aluminoxanes and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of cations containing or not containing active hydrogen groups and non-coordinating anions, lanthanide salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing fluoro groups.

[0118] The transition metal compounds described above may be used supported on an inorganic or organic compound. Preferred supports are porous oxides of inorganic or organic compounds, specifically including ion-exchange layered silicates such as montmorillonite, SiO2, Al2O3, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, or mixtures thereof.

[0119] Examples of organometallic compounds that may be used as needed include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferred.

[0120] Furthermore, as the polyolefin, ethylene polymers or copolymers of ethylene and α-olefins may be used individually or in combination of two or more types.

[0121] <Acetaldehyde> Acetaldehyde is an important chemical used as an industrial raw material. For example, acetaldehyde is useful as a raw material for acetic acid and ethyl acetate.

[0122] Acetaldehyde can be produced by oxidizing ethanol using conventionally known methods. For example, acetaldehyde can be produced by oxidizing ethanol with chlorine. Chlorine is usually reacted with ethanol in a gaseous state. Chlorine may be supplied at approximately 100% concentration, or it may be supplied diluted with an inert gas (e.g., nitrogen, helium, neon, argon, etc.). In this case, the degree of dilution is 50% by weight or less, preferably 25% by weight or less, taking into consideration the reaction efficiency. It is preferable to react ethanol and chlorine at a supply rate of 25 to 100 sccm per 100 g of aqueous ethanol solution.

[0123] The oxidation of ethanol with chlorine is preferably carried out using chlorine gas, hydrogen chloride, phosphorus pentachloride, phosphorus trichloride, phosphorus oxychloride, thionyl chloride, hypochlorite compounds, or other chlorine-containing compounds. This oxidation can be achieved, for example, by photoreaction, thermal reaction, or catalytic reaction. Among these, oxidation of ethanol by photochlorination or thermal chlorination with chlorine gas is preferred, and oxidation by photochlorination with chlorine gas is more preferred. As for the photoreaction, methods include irradiating with light of various wavelengths such as ultraviolet light and visible light, but among these, it is preferable to irradiate with light from a light source having a wavelength of about 300 to 500 nm to carry out the reaction. The light source is not particularly limited, and fluorescent lamps, mercury lamps, halogen lamps, xenon lamps, metal halide lamps, excimer lamps, LED lamps, etc., can be used. The reaction temperature is preferably around 0 to 80°C, and more preferably around 0 to 50°C. The reaction time is preferably around 1 to 5 hours.

[0124] Another example is the production of acetaldehyde by oxidizing ethanol in the gas phase in the presence of oxygen molecules and a catalyst. As such a catalyst, for example, a base metal oxide in which gold nanoparticles are dispersed and immobilized can be used. Examples of base metal oxides include La2O3, MoO3, Bi2O3, SrO, Y2O3, MgO, BaO, WO3, CuO, and composite oxides containing one or more of these.

[0125] The oxidation reaction of ethanol is carried out by contacting a gas containing ethanol and oxygen molecules with the catalyst at, for example, 100 to 280°C. The oxygen molecules used in the reaction may be supplied as oxygen gas or air may be used. The raw material gas may also contain a diluent gas (carrier gas) as needed. The apparatus used in this reaction may be a general apparatus that is normally used when carrying out gas-phase reactions. For example, the reaction is carried out by filling a reaction tube with the catalyst, heating the reaction tube to a predetermined temperature, introducing a gas containing ethanol and oxygen gas or air into the reaction tube, contacting these raw material gases with the catalyst, and recovering the reaction gas. The reaction pressure can be at atmospheric pressure, but may be increased to about 0.5 to 5 Pa (atmospheres) if necessary. As a diluent gas, so-called inert gases such as nitrogen, argon, helium, and carbon dioxide can be used. The amount of diluent gas used should be appropriately determined considering the composition of the raw material gas, the flow rate, the heat of reaction, etc., but it is usually preferable to use 1 to 100 times the volume of ethanol.

[0126] The ratio of ethanol to oxygen molecules (oxygen gas) supplied to the reaction tube is not particularly limited, but is usually 0.5 to 100% by volume of oxygen gas or oxygen gas from air relative to ethanol, preferably 1 to 10% by volume, and more preferably 2 to 5% by volume. The amount of catalyst used is also not particularly limited, but under conditions where the inner diameter of the reaction tube is 6 to 10 mm, it is generally sufficient to use about 0.1 to 1.0 g. In practical terms, in relation to the gas flow rate, the space velocity (SV) is 10,000 to 40,000 hr. -1 ·ml·gcat -1 It is preferable to use an amount that falls within a certain range.

[0127] Furthermore, acetaldehyde can also be produced by dehydrogenating ethanol in the presence of a catalyst. As such a catalyst, for example, a solid catalyst containing copper as an active species can be used. The copper as an active species can be any form that has the activity to convert ethanol to acetaldehyde, and may be metallic copper (elemental), copper compounds (oxides, hydroxides, copper salts (inorganic salts such as copper sulfate, copper phosphate, copper nitrate, copper carbonate; organic salts such as copper salts of carboxylic acids, etc.)), etc.). The solid catalyst may contain at least one selected from such elemental copper and copper compounds. The copper as an active species is preferably in the form of metallic copper. The copper may be used as is in the form of metallic copper or a copper compound, or it may be used in a form supported on a carrier. The copper as an active species only needs to act as the main catalyst of the solid catalyst, and may be used in combination with co-catalysts, etc. The solid catalyst may also be in a form in which both copper and co-catalysts are supported on a carrier.

[0128] The above dehydrogenation reaction only requires contact between ethanol and a solid catalyst, and may be a liquid-phase reaction, but is usually a gas-phase reaction in which gaseous ethanol and a solid catalyst are contacted in the gas phase. From the standpoint of the equilibrium relationship between ethanol and acetaldehyde and catalyst lifetime, the reaction temperature may be 150 to 350°C, preferably 170 to 300°C, and more preferably around 200 to 280°C. Note that the higher the reaction temperature, the more the equilibrium shifts towards acetaldehyde, thus improving the conversion rate. The reaction may be carried out under pressure, but may also be carried out under atmospheric pressure for simplicity. Furthermore, it may be carried out under reduced pressure, which is advantageous for the ethanol conversion rate.

[0129] <Acetic acid> Acetic acid is an important chemical used as an industrial raw material. For example, it is useful as a raw material for vinyl acetate monomer, acetic anhydride, and acetic acid esters.

[0130] Acetic acid can be produced by conventionally known methods of oxidation of acetaldehyde. For example, acetic acid can be produced by air oxidation of acetaldehyde in the presence of a catalyst. Examples of catalysts include manganese acetate and cobalt acetate.

[0131] <Ethyl-t-butyl ether> Ethyl t-butyl ether (ETBE) is an important chemical used as an industrial raw material. ETBE is useful, for example, as an alternative fuel to gasoline, especially as a premium fuel.

[0132] ETBE can be synthesized from ethanol and isobutene by conventionally known methods. For example, it can be produced by reacting ethanol and isobutene in the presence of a reaction catalyst. The molar ratio of isobutene to ethanol is preferably 0.1 to 10 moles, and more preferably 0.5 to 2 moles.

[0133] It is preferable to use a cation exchange resin as the reaction catalyst, and more preferably a strongly acidic cation exchange resin. As such a strongly acidic cation exchange resin, a porous type (MR type) styrene resin into which strong acidic groups such as sulfonic acid groups (-SO3H) have been introduced as ion exchange groups is preferred. The particle size of the strongly acidic cation exchange resin is preferably 0.5 to 1.0 mm. The amount of reaction catalyst used is preferably 1 to 90 g, more preferably 1 to 90 g, and even more preferably 4 to 9 g per mole of ethanol.

[0134] Furthermore, the method of using the reaction catalyst is not particularly limited and can be used in the reaction in the form of a fixed bed, fluidized bed, or suspension bed. Also, there are no particular restrictions on the method of reacting isobutene with ethanol, but it is preferable to carry out the reaction in a pressurized gas-liquid mixed-phase reaction method that can maintain the liquid phase of ethanol. In this case, the yield of ETBE obtained is further improved.

[0135] <Ester> A wide variety of esters can be synthesized by reacting ethanol with various carboxylic acids. For example, ethyl benzoate can be obtained from ethanol and benzoic acid, and diethylene glycol, a raw material for polyester, can be obtained from ethanol via ethylene. By using the ethanol of the present invention to produce polyethylene, it becomes possible to realize the ultimate resource-recycling society that does not rely on petroleum resources.

[0136] Polyesters consist of diol units and dicarboxylic acid units, and are obtained by polycondensation reaction using ethylene glycol as the diol unit and terephthalic acid and isophthalic acid as the dicarboxylic acid unit. Ethylene glycol is obtained using ethanol as a raw material in this invention, for example, by conventionally known methods such as producing ethylene glycol via ethylene oxide from ethanol.

[0137] As dicarboxylic acids, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their derivatives can be used without limitation. Examples of aromatic dicarboxylic acids include terephthalic acid and isophthalic acid, and examples of derivatives of aromatic dicarboxylic acids include lower alkyl esters of aromatic dicarboxylic acids, specifically methyl esters, ethyl esters, propyl esters, and butyl esters. Among these, terephthalic acid is preferred, and dimethyl terephthalate is preferred as a derivative of aromatic dicarboxylic acid. Examples of aliphatic dicarboxylic acids include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, and cyclohexanedicarboxylic acid, which are typically chain-like or alicyclic dicarboxylic acids with 2 to 40 carbon atoms. Examples of derivatives of aliphatic dicarboxylic acids include lower alkyl esters such as methyl esters, ethyl esters, propyl esters, and butyl esters of the above aliphatic dicarboxylic acids, and cyclic acid anhydrides of the above aliphatic dicarboxylic acids, such as succinic anhydride. Among these, adipic acid, succinic acid, dimer acid, or mixtures thereof are preferred, with succinic acid being particularly preferred. As for the aliphatic dicarboxylic acid derivatives, methyl esters of adipic acid and succinic acid, or mixtures thereof are more preferred.

[0138] Polyesters can be obtained by conventionally known methods of polycondensation of the diol units and dicarboxylic acid units described above. Specifically, they can be produced by general melt polymerization methods such as esterification and / or transesterification reactions between the dicarboxylic acid component and the diol component, followed by a polycondensation reaction under reduced pressure, or by known solution heating dehydration condensation methods using organic solvents.

[0139] The polycondensation reaction is preferably carried out in the presence of a polymerization catalyst, and examples of polymerization catalysts include titanium compounds, zirconium compounds, and germanium compounds.

[0140] The reaction temperature for the esterification and / or transesterification reactions between dicarboxylic acid and diol components is typically in the range of 150-260°C, and the reaction atmosphere is usually under an inert gas atmosphere such as nitrogen or argon.

[0141] In the polycondensation reaction step, a chain extender (coupling agent) may be added to the reaction system. After the polycondensation is complete, the chain extender is added to the reaction system in a uniform molten state without a solvent and reacted with the polyester obtained by polycondensation.

[0142] After the obtained polyester is solidified, solid-phase polymerization may be performed as needed to further increase the degree of polymerization or to remove oligomers such as cyclic trimers.

[0143] In the manufacturing process of polyester, various additives may be added as long as their properties are not impaired. For example, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather-resistant agents, antistatic agents, friction reducers, mold release agents, antioxidants, ion exchange agents, coloring pigments, etc., can be added.

[0144] The ethanol according to the present invention is not limited to the polymers described above, but can be used as a raw material for various other polymers. Since the molded articles of the resulting polymers are carbon-neutral materials, it becomes possible to realize the ultimate resource-recycling society that does not rely on petroleum resources.

[0145] <Products containing ethanol> The ethanol according to the present invention can be used not only as a polymer raw material as described above, but also in a variety of other products. Examples of such products include cosmetics, perfumes, fuels, antifreeze, disinfectants, sterilizers, cleaning agents, mold removers, detergents, shampoos, soaps, antiperspirants, facial cleansing wipes, solvents, paints, adhesives, diluents, and food additives. By using it in these applications, it can exhibit appropriate effects according to the intended use.

[0146] <Fuel> The ethanol according to the present invention can also be used as a raw material for fuels (e.g., jet fuel, kerosene, diesel fuel, gasoline). Because ethanol has high bactericidal properties, it can also function as a disinfectant to prevent the proliferation of bacteria and other microorganisms in fuel systems such as engines and piping.

[0147] The Japanese Society of Automotive Engineers of Japan (JSAE) standard (2006) stipulates that the ethanol concentration in fuel ethanol must be 99.5% by volume or higher. Other countries (for example, India) also stipulate that the ethanol concentration in fuel ethanol must be 99.5% by volume or higher. Therefore, ethanol with a purity of 99.5-99.9% by volume is suitable for use in ethanol-only vehicles. Furthermore, since fuel ethanol can be used for purposes other than ethanol-only vehicles, ethanol with a purity of 99.5-99.9% by volume is particularly versatile.

[0148] Furthermore, the ethanol produced by this invention can be mixed with gasoline to be used as ethanol-blended gasoline. Using ethanol-blended gasoline can reduce the environmental impact. The ethanol used in ethanol-blended gasoline has a purity of 92.0% by volume or higher, preferably 95.0% by volume or higher, and more preferably 99.5% by volume or higher.

[0149] The ethanol content in ethanol-blended gasoline is preferably 1% to 15% by volume, more preferably 2% to 12% by volume, and even more preferably 3% to 10% by volume. If the ethanol content is 1% or more by volume, the advantage of improving the octane number due to ethanol blending can be obtained, and if it is 15% or less by volume, the evaporation characteristics will not change significantly due to azeotropic phenomena with other gasoline base materials, and the proper drivability of gasoline vehicles can be ensured.

[0150] Furthermore, the water content in the ethanol-blended gasoline is preferably 0.01% by mass or more and 0.9% by mass or less, and more preferably 0.01% by mass or more and 0.7% by mass or less. The lower limit of the water content depends on the saturated water content of the gasoline base material and the water content in the ethanol, but is substantially around 0.01% by mass. If the upper limit is 0.9% by mass or less, phase separation can be prevented, and even if phase separation occurs, the gasoline layer will enable proper operation of the gasoline engine. The water content can be measured according to the "Crude oil and petroleum products - Water content test method" described in JIS K 2275, and for example, the Karl Fischer coulometric titration method can be used.

[0151] As the gasoline base material, any commonly used gasoline base material can be used as desired and is not particularly limited. Examples of gasoline base materials include light naphtha obtained by atmospheric distillation of crude oil, preferably desulfurized light naphtha obtained by desulfurizing light naphtha, catalytically reformed gasoline obtained by desulfurizing and catalytically reforming heavy naphtha, debenzene catalytically reformed gasoline obtained by debenzene treatment of debenzene, debenzene light catalytically reformed gasoline, debenzene heavy catalytically reformed gasoline, and mixtures thereof, cracked gasoline obtained by catalytic cracking or hydrocracking, light cracked gasoline, heavy cracked gasoline, and mixtures thereof, and isomerized gasoline obtained by isomerizing light naphtha.

[0152] Furthermore, the ETBE produced from ethanol according to the invention can be mixed with gasoline to be used as ETBE-blended gasoline. By using ETBE-blended gasoline, the environmental burden can be reduced. The ETBE content of the ETBE-blended gasoline is preferably 1% to 15% by volume, more preferably 2% to 12% by volume, and even more preferably 3% to 10% by volume. If the ETBE content is 1% or more by volume, the advantage of improved octane number due to ETBE blending can be obtained, and if it is 15% or less by volume, the evaporation characteristics will not change significantly due to azeotropic phenomena with other gasoline base materials, and the proper drivability of gasoline vehicles can be ensured. [Examples]

[0153] Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[0154] <Method for Evaluating Ethanol Component> In the following examples and comparative examples, the contents of aliphatic hydrocarbons (n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane) in ethanol were measured using a gas chromatography apparatus (GC-2014, manufactured by SHIMADZU Corporation) by the GC / MS method. The measurement conditions were as follows. Column: DB-WAX (length 60 m, inner diameter 0.25 mm, film thickness 0.25 μm) Oven temperature: 40°C for 1 minute → 5°C / minute → 100°C for 10 minutes → 10°C / minute → 250°C for 4 minutes Sampling time: 5 minutes Carrier gas: He (3.0 mL / minute)

[0155] <Method for Quantifying Butadiene> The quantitative evaluation of butadiene was performed by analysis using a gas chromatography apparatus (GC-2014, manufactured by SHIMADZU Corporation). The measurement conditions were as follows. <Analysis Conditions of GC / MS Method> Column: Rt-Q-BOND (length 30 m, inner diameter 0.32 mm, film thickness 10 μm) Oven temperature: 60°C for 11.5 minutes → 10°C / minute → 100°C for 14.5 minutes → 10°C / minute → 250°C Sampling time: 5 minutes Carrier gas: He (30 cm / s) Split ratio: 75

[0156] <Method for Quantifying Ethyl Benzoate> The quantitative evaluation of ethyl benzoate was performed by analysis using a gas chromatography apparatus. The measurement conditions were as follows. <Analysis Conditions of GC / MS Method> Column: DB-1 (length 30.0 m, inner diameter 0.254 mm, film thickness 0.25 m) Heating conditions: 30℃-300℃, 15℃ / min Carrier gas: He 100kPa Split ratio: 50

[0157] <Method for determining combustion efficiency> The combustion efficiency of ethanol was quantitatively evaluated by total calorific value analysis using a cone calorimeter manufactured by FTT Corporation.

[0158] [Example 1] <Preparation of ethanol> Ethanol was produced in the following manner. (Raw material gas generation process) The gas used was the gas emitted after burning general waste at a waste incineration facility. The raw material gas consisted of approximately 30% carbon monoxide, 30% carbon dioxide, 30% hydrogen, and 10% nitrogen.

[0159] (Synthesis gas purification process) The raw material gas produced as described above was heated to 80°C using a PSA (Pressure Sequestration) device to remove carbon dioxide from the synthesis gas, reducing its content to 60-80% of the original amount (approximately 30% by volume). Then, the gas was heated again using a double-tube heat exchanger with 150°C steam and recooled using a double-tube heat exchanger with 25°C cooling water to precipitate impurities. These precipitated impurities were then removed using a filter to produce synthesis gas.

[0160] (Microbial fermentation process) A continuous fermentation apparatus (microbial fermentation tank) equipped with a main reactor, a synthesis gas supply port, and an exhaust port, was filled with Clostridium autoethanogenum (microorganism) inoculum and a liquid culture medium for bacterial cultivation (containing appropriate amounts of phosphorus compounds, nitrogen compounds, and various minerals, etc.). Synthesis gas obtained as described above was continuously supplied to the apparatus, and cultivation (microbial fermentation) was carried out continuously for 300 hours. After that, approximately 8,000 liters of the culture solution containing ethanol were withdrawn from the exhaust port.

[0161] (separation process) The culture solution obtained in the above fermentation process was subjected to a solid-liquid separation filter device under conditions of a culture solution introduction pressure of 200 kPa or higher to obtain an ethanol-containing solution.

[0162] (Distillation process) Next, the ethanol-containing liquid was introduced into a distillation apparatus equipped with a heater using 170°C steam. After raising the temperature at the bottom of the distillation column to 101°C within 8 to 15 minutes, the ethanol-containing liquid was introduced from the middle of the distillation column. During continuous operation, the column was operated continuously at 101°C at the bottom, 99°C in the middle, and 91°C at the top, at a rate of 15 seconds / L, to obtain purified ethanol. The n-hexane content in the obtained ethanol was 0.1 mg / L, the n-heptane content was 0.04 mg / L, the n-octane content was 0.02 mg / L, the n-decane content was 0.32 mg / L, the n-dodecane content was 0.1 mg / L, and the tetradecane content was 0.03 mg / L.

[0163] (Method for producing butadiene) Butadiene was produced using the ethanol obtained as described above. First, the obtained ethanol was vaporized by passing it through a single tube heated to 90°C to be used as a gas for the reaction, and the vaporized ethanol gas was combined with nitrogen. The flow rate of the ethanol gas was controlled by mass flow so that it was SV360 L / hr / L and the nitrogen was SV840 L / hr / L to obtain a mixed gas of 30 vol% ethanol (gas equivalent) and 70 vol% nitrogen (gas equivalent). Next, a butadiene-containing gas was obtained by continuously supplying the above mixed gas through a stainless steel cylindrical reaction tube with a diameter of 1 / 2 inch (1.27 cm) and a length of 15.7 inches (40 cm), which was filled with 0.85 g of a butadiene synthesis catalyst mainly composed of Hf, Zn, and Ce, while maintaining the temperature at 350°C and the pressure (pressure of the reaction bed) at 0.1 MPa. The butadiene content of the obtained butadiene-containing gas was quantified using a GC-2014 gas chromatography apparatus (manufactured by SHIMADZU). The results are shown in Table 1.

[0164] [Comparative Example 1] Butadiene was produced using 99-degree ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.), which is derived from fossil fuels, in the same manner as in Example 1, and the butadiene content was quantified in the same manner as in Example 1. The results are shown in Table 1. Furthermore, n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane in the 99-degree ethanol, which is derived from fossil fuels, were all below the detection limit.

[0165] [Comparative Example 2] Butadiene was produced using 99-degree ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.), derived from the saccharification and fermentation of plants, in the same manner as in Example 1, and the butadiene content was quantified in the same manner as in Example 1. The results are shown in Table 1. Furthermore, n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-tetradecane in the 99-degree ethanol, which is derived from fossil fuels, were all below the detection limit.

[0166] [Table 1]

[0167] As shown in Table 1, ethanol produced using gas emitted after burning general waste in a waste incineration facility was found to have a higher conversion efficiency to butadiene compared to conventional ethanol derived from fossil fuels or ethanol derived from saccharification and fermentation of plants.

[0168] [Example 2] (Production of ethyl benzoate) Ethyl benzoate was prepared using the same ethanol as in Example 1, as follows: First, 36.8 g of benzoic acid and 200 ml of ethanol were mixed under an argon stream, and 9 ml of concentrated sulfuric acid was added and the mixture was stirred under reflux for 5 hours. After that, the mixture was allowed to cool to room temperature, unreacted ethanol was removed under reduced pressure, and the ethyl benzoate synthesized with 100 ml of diethyl ether was recovered. The recovered liquid was washed with distilled water, dried using magnesium sulfide, and then filtered and concentrated. The obtained filtrate was analyzed for its components using a gas chromatography apparatus to quantify the amount of ethyl benzoate synthesized. The analytical conditions are shown below. The analytical results are shown in Table 2. Column: DB-1 (Length 30.0m, Inner diameter 0.254mm, Film thickness 0.25m) Heating conditions: 30-300℃, 15℃ / min Carrier gas: He 100kPa Split ratio: 50

[0169] [Comparative Example 3] Ethyl benzoate was produced and quantified in the same manner as in Example 2, except that petrochemical-derived ethanol used in Comparative Example 1 was used. The analytical results are shown in Table 2.

[0170] [Comparative Example 4] Ethyl benzoate was produced and quantified in the same manner as in Example 2, except that petrochemical-derived ethanol used in Comparative Example 2 was used. The analytical results are shown in Table 2.

[0171] [Table 2]

[0172] As shown in Table 2, ethanol produced using gas emitted after burning general waste in waste incineration facilities was found to have a higher conversion efficiency to ethyl benzoate compared to conventional ethanol derived from fossil fuels or ethanol derived from saccharification and fermentation of plants.

[0173] [Example 3] The combustion efficiency of ethanol was quantified using the same ethanol used in Example 1. Fuel efficiency was quantified by adding 30g of ethanol to a heat-resistant container measuring 60mm in length, 60mm in width, and 30mm in height under no heating conditions, igniting it, measuring the amount of oxygen lost until complete combustion occurred in a cone calorimeter (manufactured by FTT), and calculating the total calorific value based on the amount of oxygen lost. The quantitative results are shown in Table 3.

[0174] [Comparative Example 5] The combustion efficiency of ethanol was quantified in the same manner as in Example 3, except that the ethanol used in Comparative Example 1 was used. The quantitative results are shown in Table 3.

[0175] [Comparative Example 6] The combustion efficiency of ethanol was quantified in the same manner as in Example 3, except that the ethanol used in Comparative Example 2 was used. The quantitative results are shown in Table 3.

[0176] [Table 3]

[0177] As shown in Table 3, ethanol produced using gas emitted after burning general waste in a waste incineration facility was found to have higher combustion efficiency compared to conventional ethanol derived from fossil fuels or ethanol derived from saccharification and fermentation of plants.

Claims

[Claim 1] A waste-derived ethanol composition obtained from synthesis gas containing waste-derived carbon monoxide and hydrogen through the fermentation action of gas-assimilating bacteria as microorganisms, A waste-derived ethanol composition having an aliphatic hydrocarbon content of 0.16 mg / L or more and 10 mg / L or less.

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