ethanol

Abstract

To provide an ethanol with a controlled content of a specific inorganic component.SOLUTION: An ethanol according to the invention has a chromium content of 0.6 mg / L or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to ethanol, more specifically, to ethanol with adjusted contents of specific trace elements. Furthermore, the present invention relates to a novel resource-recycling ethanol that uses a gas containing carbon monoxide and hydrogen as a substrate, rather than being derived from conventional petroleum resources or biomass resources. [Background technology]

[0002] Petrochemical products are used in many aspects of our lives. However, because they are familiar products, their mass production and mass consumption have caused various environmental problems, which has become a major global issue. For example, polyethylene and polyvinyl chloride, which are representative petrochemical industry products, are consumed in large quantities and thrown away, and their waste is a major cause of environmental pollution. In addition, concerns about the depletion of fossil fuel resources and the increase in carbon dioxide in the atmosphere due to the mass production of petrochemical industry products are also being discussed as global environmental problems.

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

[0004] To solve this problem, the use of non-edible raw materials that have traditionally been discarded has also been considered. Specifically, methods have been proposed for producing alcohols by fermentation using non-edible raw materials such as cellulose derived from waste wood or waste paper, and for producing alcohols from the synthesis gas by gasifying the biomass raw materials described above using a catalyst, but these methods have not yet been put to practical use. Furthermore, even if various petrochemical products could be produced from these non-petroleum raw materials, they would ultimately end up as waste plastics that do not decompose naturally, and therefore cannot be said to be effective as a fundamental solution to environmental problems.

[0005] Incidentally, approximately 60 million tons of combustible waste are currently discarded in Japan per year. This amounts to approximately 200 trillion kilocalories of energy, far exceeding the energy content of naphtha, a raw material for plastics used in Japan, making this waste a valuable resource. Converting these waste resources into petrochemical products would enable the realization of an ultimate resource-circulating society that is not dependent on petroleum resources. From this perspective, Patent Documents 1 and 2, etc., disclose technologies for producing synthetic gas (a gas primarily composed of CO and H2) from waste and then producing ethanol from the synthetic 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, making productivity a major challenge in producing alcohol from synthesis gas by microbial fermentation. Furthermore, 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. Therefore, the development of derivatives 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 Application Laid-Open No. 2016-059296 [Patent Document 2] International Publication No. 2015-037710 [Patent Document 3] Japanese Patent Application Publication No. 2018-058042 Summary of the Invention [Problem to be solved by the invention]

[0008] According to the research of the present inventors, for example, C2 raw materials, such as conventional ethanol, are known to be starting materials for various chemical products. However, as described above, it has been found that alcohol produced from resources (recyclable resources) that do not rely on petroleum resources or biomass resources contains trace amounts of various unknown substances, unlike chemical raw materials derived from naphtha. However, in conventional technology, the properties of the substances are unknown, and there has been insufficient consideration in the past as to whether it is necessary to remove all substances or only specific substances. Therefore, even though the above patent documents propose alcohol produced from recyclable resources, there is still room for technological improvement before such alcohol can be put to practical use.

[0009] On the other hand, although the above-mentioned documents disclose general fermentation and distillation methods and the optimal composition of synthetic gas, they do not describe the details of the processes, nor do they specify the alcoholic substance obtained.

[0010] The present invention has been made in view of the above background art, and an object of the present invention is to provide novel alcohols and their derivatives which are practical and have industrial value more than existing petrochemical raw materials. [Means for solving the problem]

[0011] As a result of intensive research aimed at solving the above-mentioned problems, the inventors have identified a wide variety of trace substances contained in alcohol produced from recyclable resources, and have found that it is possible to control the contents within a specific range using a new production method, and that various derivatives thereof exhibit superior effects compared to existing petroleum-derived alcohols. For example, in the process of synthesizing butadiene from ethanol, the inventors have found that the ethanol conversion rate is improved compared to when conventional petroleum-derived ethanol is used, and that alcohol of a practical level equal to or better than petroleum-derived alcohol can be obtained, thereby completing the present invention.

[0012] More specifically, the inventors 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 is improved when butadiene is synthesized from the ethanol. Further investigation into the reason for this finding revealed that ethanol derived from recycled resources using a gas containing carbon monoxide and hydrogen as a substrate has an extremely low content of specific metal elements. The present invention is based on this finding.

[0013] That is, the present invention includes the following gist. [1] Ethanol containing less than 0.6 mg / L of chromium. [2] The ethanol according to [1], which uses a gas containing carbon monoxide and hydrogen as a substrate. [3] Ethanol according to [1] or [2], which is derived from microbial fermentation. [4] The ethanol according to [2], wherein the gas containing carbon monoxide and hydrogen is derived from waste. [5] converting a carbon source into a synthesis gas comprising carbon monoxide and hydrogen; a microbial fermentation step of supplying the synthesis gas containing carbon monoxide and hydrogen to a microbial fermenter and obtaining an ethanol-containing liquid by microbial fermentation; a separation step of separating the ethanol-containing liquid into a liquid or solid component containing microorganisms and a gas component containing ethanol; a liquefaction step of condensing and liquefying the gas components; a purification step of purifying ethanol from the liquid obtained in the liquefaction step; Including, A method for producing ethanol, wherein the purified ethanol has a chromium content of 0.6 mg / L or less. [6] The method according to [5], further comprising the step of purifying the synthesis gas. [7] The method according to [5] or [6], wherein the carbon source is derived from waste. [8] Ethanol according to any one of [1] to [4], which is for use in chemical products. [9] Ethanol according to any one of [1] to [4], which is for use as fuel.

[10] The ethanol according to any one of [1] to [4], which is used as a polymer raw material.

[11] A chemical product made from the ethanol according to any one of [1] to [4].

[12] A fuel comprising the ethanol according to any one of [1] to [4] and / or ethyl t-butyl ether obtained from the ethanol according to any one of [1] to [4].

[13] A polymer raw material obtained by using ethanol as a raw material according to any one of [1] to [4].

[14] The polymer raw material according to

[13] , wherein the polymer raw material is selected from the group consisting of ethylene, propylene, butadiene, ethyl acetate, isobutene, methyl (meth)acrylate, acrylic acid, aminohexanoic acid, and diethyl carbonate.

[15] A polymer made from the polymer raw material described in

[13] or

[14] .

[16] A molded article made of the polymer according to

[15] . [Effects of the Invention]

[0014] According to the present invention, by producing ethanol with an extremely low content of specific metal elements, various unique effects can be obtained compared to commercially available industrial ethanol. For example, according to the present invention, it is possible to improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, to improve the reaction rate when synthesizing carboxylic acid esters by adding ethanol to carboxylic acids, and to improve the combustion efficiency when using ethanol as fuel. In addition, it is expected that similar effects can be obtained even with existing alcohols by adjusting the content of specific metal elements to an extremely low content.

[0015] Furthermore, the ethanol according to the present invention can be used as a raw material for producing, for example, 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. Furthermore, the ethanol according to the present invention can be used in a variety of applications for chemical products, such as cosmetics, perfumes, fuels, antifreeze, disinfectants, disinfectants, cleaning agents, mold removers, detergents, hair washes, soaps, antiperspirants, facial cleansing sheets, solvents, paints, adhesives, diluents, and food additives. DETAILED DESCRIPTION OF THE INVENTION

[0016] An example of a preferred embodiment of the present invention will be described below. However, the following embodiment is an example for explaining the present invention, and the present invention is not limited to the following embodiment.

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

[0018] <Ethanol> The Cr (chromium) content in the ethanol according to the present invention is 0.6 mg / L or less, and preferably 0.5 mg / L or less. The Cr content is the amount of Cr compounds converted to Cr element. Having the Cr content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0019] The chromium content in ethanol can be measured by a conventionally known method. For example, a method for measuring the chromium content includes an analysis method using an inductively coupled plasma mass spectrometry (ICP-MS). In the analysis method using ICP-MS, a standard solution for atomic absorption is analyzed after adjusting its concentration to prepare a calibration curve, and the chromium content is determined by analyzing the sample to be measured based on this calibration curve.

[0020] The ethanol used in the present invention is preferably ethanol produced from a gas containing carbon monoxide and hydrogen as a substrate, or ethanol derived from microbial fermentation. This is because adjusting the chromium content to the above-mentioned concentration is easy in the production process of these ethanols. Furthermore, although commercially available industrial ethanol derived from fossil fuels typically contains chromium at concentrations exceeding the above-mentioned concentration, the chromium content may be adjusted to the above-mentioned concentration by further refining.

[0021] Without being bound by theory, it is believed that in the present invention, by reducing the content of specific metals in ethanol to an extremely low value, it is possible to improve the ethanol conversion rate when butadiene is synthesized using ethanol as a raw material, to improve the reaction rate when a carboxylic acid ester is synthesized by adding ethanol to a carboxylic acid, and to improve the combustion efficiency when ethanol is used as a fuel.

[0022] The ethanol according to the present invention may contain inorganic components other than Cr, such as Si, K, and Na. Compounds containing these elements may be inorganic compounds or organometallic compounds.

[0023] 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 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 is the amount of Si compounds converted into elemental Si. Having the Si content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0024] When K is contained 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 preferably 10 mg / L or less, more preferably 7 mg / L or less, and even more preferably 5 mg / L or less, relative to the ethanol. The K content is the amount of K compound converted into K element. 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 a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0025] When Na is contained in ethanol, the Na content is preferably 150 mg / L or more, more preferably 170 mg / L or more, even more preferably 190 mg / L or more, and preferably 1000 mg / L or less, more preferably 500 mg / L or less, even more preferably 400 mg / L or less, and more preferably 300 mg / L or less, relative to the ethanol. The Na content is the amount of Na compounds converted into Na element. Having a Na content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0026] 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 the ethanol. The Fe content is the amount of Fe compounds converted into elemental Fe. Having an Fe content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0027] The ethanol of the present invention is obtained by extracting and further purifying the ethanol-containing liquid obtained from the microbial fermenter as described below. However, other components may be contained in addition to the unavoidable substances described above. For example, trace amounts of aromatic compounds may be contained. Examples of aromatic compounds include toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene. Only one of these may be contained, or two or more of these may be contained. Preferably, the aromatic compound contains ethylbenzene.

[0028] The content (total) 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 0.7 mg / L or more, even more preferably 1.0 mg / L or more, and preferably 10 mg / L or less, more preferably 7 mg / L or less, even more preferably 5 mg / L or less, and even more preferably 3 mg / L or less, relative to the total ethanol. Having the aromatic compound content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0029] When ethylbenzene is contained in ethanol, the ethylbenzene content, relative to the total ethanol, 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, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less. Having an ethylbenzene content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0030] When ethanol contains toluene, the toluene content, relative to the total ethanol, 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having a toluene content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0031] When o-xylene is contained in ethanol, the o-xylene content, relative to the total ethanol, 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, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less. Having an o-xylene content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0032] When m-xylene and / or p-xylene is contained in ethanol, 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, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less, based on the total ethanol. Having the m-xylene and / or p-xylene content within the above ranges can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0033] The ethanol according to the present invention may further contain a trace amount of aliphatic hydrocarbons. Examples of aliphatic hydrocarbons include n-hexane, n-heptane, n-octane, n-decane, n-dodecane, n-tetradecane, and hexadecane. Only one of these may be contained, or two or more may be contained. Preferably, the aliphatic hydrocarbon contains one or more of n-hexane, n-decane, and n-dodecane.

[0034] The total content of aliphatic hydrocarbons in ethanol is preferably 0.16 mg / L or more, preferably 0.2 mg / L or more, more preferably 0.3 mg / L or more, even more preferably 0.5 mg / L or more, and 10 mg / L or less, 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 ethanol. Having the aliphatic hydrocarbon content within the above ranges can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0035] When n-hexane is contained in ethanol, the content of n-hexane 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, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less, based on the total ethanol. Having an n-hexane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0036] When n-heptane is contained in ethanol, the content of n-heptane relative to the total ethanol 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having an n-heptane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0037] When n-octane is contained in ethanol, the n-octane content, based on the total ethanol, 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having an n-octane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0038] When n-decane is contained in ethanol, the content of n-decane relative to the total ethanol 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having an n-decane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0039] When n-dodecane is contained in ethanol, the content of n-dodecane relative to the total ethanol 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having an n-dodecane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0040] When n-tetradecane is contained in ethanol, the content of n-tetradecane relative to the total ethanol 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having the n-tetradecane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0041] When hexadecane is contained in ethanol, the content of hexadecane relative to the total ethanol 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, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less. Having a hexadecane content within the above range can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0042] The ethanol according to the present invention may further contain a trace amount of dialkyl ether. Examples of dialkyl ethers include dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, and dipentyl ether. Only one of these may be contained, or two or more of these may be contained. As the dialkyl ether, dibutyl ether is preferably contained.

[0043] The total content of dialkyl ethers in ethanol is preferably 0.001 mg / L or 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 is 100 mg / L or less, preferably 80 mg / L or less, more preferably 50 mg / L or less, and even more preferably 30 mg / L or less, relative to the total ethanol. Having the dialkyl ether content within the above ranges can improve the ethanol conversion rate when synthesizing butadiene using ethanol as a raw material, improve the reaction rate when synthesizing a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0044] When dibutyl ether is contained in ethanol, the content of dibutyl ether relative to ethanol is preferably 1 mg / L or more, more preferably 2 mg / L or more, even more preferably 5 mg / L or more, still more preferably 10 mg / L or more, and preferably 50 mg / L or less, more preferably 40 mg / L or less, even more preferably 30 mg / L or less, and still 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 a carboxylic acid ester by adding ethanol to a carboxylic acid, and improve the combustion efficiency when using ethanol as a fuel.

[0045] The ethanol of the present invention contains the inorganic components described above and, if desired, trace amounts of organic components such as aromatic hydrocarbons and aliphatic hydrocarbons. However, the concentration of ethanol, which is the main component in the ethanol (pure ethanol as a compound), 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, still more preferably 98% by volume or more, and is 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 still more preferably 99.5% by volume or less, based on the total ethanol.

[0046] The ethanol concentration in the ethanol of the present invention may be set according to the intended use, for example, 90% by volume or more is preferably used for cosmetics, and 75% by volume or more is preferably used for disinfectant ethanol, and the upper limit can also be conveniently set according to the use. In terms of transportation costs, etc., a higher ethanol concentration is preferable for the product.

[0047] <Ethanol production method> As a method for producing ethanol having the above-described characteristic gas chromatographic peak, for example, ethanol can be produced by microbial fermentation of carbon monoxide-containing synthesis gas derived from waste or exhaust gas. In such a method, the content of aromatic compounds and the like in the raw material gas derived from waste or exhaust gas and the purification conditions can be controlled to control the amount of aromatic compounds and the like contained in the final product. Below, as an example, a method for producing ethanol by microbial fermentation of carbon monoxide-containing synthesis gas derived from waste or exhaust gas will be described.

[0048] The ethanol production method includes the following steps: a step of converting a carbon source into a synthesis gas containing carbon monoxide and hydrogen, a microbial fermentation step of supplying the synthesis gas containing carbon monoxide and hydrogen to a microbial fermenter and obtaining an ethanol-containing liquid by microbial fermentation, a separation step of separating the ethanol-containing liquid into a liquid or solid component containing microorganisms and a gas component containing ethanol, a liquefaction step of condensing and liquefying the gas component, and a purification step of purifying ethanol from the liquid obtained in the liquefaction step.However, the method may also include a feedstock gas production step, a synthesis gas preparation step, a wastewater treatment step, etc., as necessary.Each step is described below.

[0049] <Material gas generation process> The raw material gas generation process is a process in which a carbon source is gasified in a gasification section to generate raw material gas. A gasification furnace may be used in the raw material gas generation process. A gasification furnace is a furnace that combusts (incompletely combusts) a carbon source, and examples include a shaft furnace, a kiln furnace, a fluidized-bed furnace, and a gasification reforming furnace. A fluidized-bed gasification furnace is preferred because partial combustion of waste enables high hearth load and excellent operability. Gasification of waste in a fluidized-bed furnace at low temperatures (approximately 450 to 600°C) and in a low-oxygen atmosphere results in decomposition into gases (carbon monoxide, carbon dioxide, hydrogen, methane, etc.) and char containing a high carbon content. Furthermore, incombustible materials contained in the waste are separated from the furnace bottom in a hygienic and low-oxidation state, allowing for selective recovery of valuable materials such as iron and aluminum from the incombustible materials. Therefore, gasification of such waste enables efficient resource recycling.

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

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

[0052] The carbon source used in the raw material gas production step is not particularly limited, and various carbon-containing materials can be suitably used for the purpose of recycling, such as coke ovens in steelworks, blast furnaces (blast furnace gas), coal used in converters and coal-fired power plants, general waste and industrial waste introduced into incinerators (particularly gasifiers), and carbon dioxide by-produced in various industries.

[0053] More specifically, the carbon source is preferably waste, and specific examples include plastic waste, food waste, municipal solid waste (MSW), industrial solid waste, discarded tires, biomass waste, household waste such as futons and paper, waste such as building materials, coal, petroleum, petroleum-derived compounds, natural gas, shale gas, and the like. Of these, various types of waste are preferred, and unsorted municipal solid waste is more preferred from the viewpoint of sorting costs.

[0054] The feed gas obtained by gasifying a carbon source contains carbon monoxide and hydrogen as essential components, but may also contain carbon dioxide, oxygen, and nitrogen. As other components, the feed gas may further contain components such as soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, and aromatic compounds.

[0055] In the raw material gas production step, the raw material gas may be produced by carrying out a heat treatment (commonly known as gasification) to combust (incompletely combust) the carbon source, i.e., by partially oxidizing the carbon source, as a gas containing carbon monoxide in an amount of, but not limited to, 0.1 vol % or more, preferably 10 vol % or more, and more preferably 20 vol % or more.

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

[0057] In particular, in the synthesis gas purification process, a pressure swing adsorption apparatus filled with the above-mentioned regenerated adsorbent is used to adsorb carbon dioxide gas in the synthesis gas onto the regenerated adsorbent (zeolite) to reduce 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. Examples of other treatment processes include gas chillers (water separation devices), cryogenic separation devices, particulate (soot) separation devices such as cyclones and bag filters, scrubbers (water-soluble impurity separation devices), desulfurization devices (sulfide separation devices), membrane separation devices, deoxygenation devices, pressure swing adsorption (PSA) separation devices, temperature swing adsorption (TSA) separation devices, pressure temperature swing adsorption (PTSA) separation devices, separation devices using activated carbon, and separation devices using deoxygenation catalysts, specifically, copper catalysts or palladium catalysts.

[0058] In the present invention, the concentrations of iron and chromium derived from the raw material gas can be controlled by adjusting the conditions of the above-mentioned treatment process. For example, by adjusting the conditions such as the residence time of the scrubber and membrane separation, these concentrations can be reduced to below the detection limit. By reducing the concentrations of iron and chromium in the raw material gas in this way, the contents of iron and chromium in the final ethanol can be reduced to below the detection limit.

[0059] The synthesis gas used in the method for producing ethanol of the present invention contains at least carbon monoxide as an essential component, and may further contain hydrogen, carbon dioxide, and nitrogen.

[0060] The synthesis gas used in the present invention may be a gas obtained by gasifying a carbon source to generate a raw material gas (raw material gas generation step), and then adjusting the concentrations of the components carbon monoxide, carbon dioxide, hydrogen, and nitrogen from the raw material gas, as well as reducing or removing the above-mentioned substances and compounds, and the gas obtained may be used as the synthesis gas.

[0061] The carbon monoxide concentration in the synthesis gas is usually 20% by volume or more and 80% by volume or less, preferably 25% by volume or more and 50% by volume or less, and more preferably 35% by volume or more and 45% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0062] The hydrogen concentration in the synthesis gas is usually 10% by volume or more and 80% by volume or less, preferably 30% by volume or more and 55% by volume or less, and more preferably 40% by volume or more and 50% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0063] The carbon dioxide concentration in the synthesis gas is usually 0.1 vol% or more and 40 vol% or less, preferably 0.3 vol% or more and 30 vol% or less, more preferably 0.5 vol% or more and 10 vol% or less, and particularly preferably 1 vol% or more and 6 vol% or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0064] The nitrogen concentration in the synthesis gas is usually 40% by volume or less, preferably 1% by volume or more and 20% by volume or less, and more preferably 5% by volume or more and 15% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0065] The concentrations of carbon monoxide, carbon dioxide, hydrogen, and nitrogen can be controlled within a predetermined range by changing the elemental composition of hydrocarbons (carbon and hydrogen) or nitrogen in the carbon source in the raw material gas generation process, or by appropriately changing combustion conditions such as the combustion temperature and the oxygen concentration of the gas supplied during combustion. For example, if you want to change the carbon monoxide or hydrogen concentration, you can change the carbon source to one with a high ratio of hydrocarbons (carbon and hydrogen), such as waste plastics, or if you want to decrease the nitrogen concentration, you can supply a gas with a high oxygen concentration in the raw material gas generation process.

[0066] In addition to the components described above, the synthesis gas used in the present invention may contain, without limitation, sulfur compounds, phosphorus compounds, nitrogen compounds, etc. 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 is 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 ensuring that the content of sulfur compounds, phosphorus compounds, nitrogen compounds, etc. is at or above the lower limit, there is an advantage that microorganisms can be cultured favorably, and by ensuring that the content is at or below the upper limit, there is an advantage that the culture medium is not contaminated by various nutrient sources not consumed by the microorganisms.

[0067] Examples of sulfur compounds include sulfur dioxide, CS, COS, and H2S, and among these, H2S and sulfur dioxide are preferred because they are easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that the sum of H2S and sulfur dioxide contained in the synthesis gas is within the above range. As the phosphorus compound, phosphoric acid is preferred because it is easily consumed as a nutrient source for microorganisms, and therefore it is more preferred that the synthesis gas contain phosphoric acid in the above range. Examples of nitrogen compounds include nitric oxide, nitrogen dioxide, acrylonitrile, acetonitrile, and HCN, and HCN is preferred because it is easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that HCN is contained in the synthesis gas in the above range.

[0068] 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, and 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 ensuring that the content is equal to or greater than the lower limit, microorganisms tend to be cultured favorably, while by ensuring that the content is equal to or less than the upper limit, the medium tends to be less susceptible to contamination by various nutrient sources not consumed by the microorganisms.

[0069] <Microbial fermentation process> The microbial fermentation step is a step of producing ethanol by microbial fermentation of the synthesis gas in a microbial fermenter. The microbial fermenter is preferably a continuous fermentation apparatus. Generally, any shape of microbial fermenter can be used, including stirred, airlift, bubble column, loop, open bond, and photobio types. In the present invention, a known loop reactor having a main tank section and a reflux section can be suitably used as the microbial fermenter. In this case, it is preferable to further include a circulation step of circulating the liquid medium between the main tank section and the reflux section.

[0070] The synthesis gas to be supplied to the microbial fermenter may be the gas obtained through the feed gas generation step as is, as long as it satisfies the above-mentioned compositional requirements for synthesis gas, or may be the gas obtained by reducing or removing impurities from the feed gas and then adding another specified gas to the resulting gas. For example, the synthesis gas may be prepared by adding at least one compound selected from the group consisting of sulfur compounds such as sulfur dioxide, phosphorus compounds, and nitrogen compounds.

[0071] The microbial fermenter may be continuously supplied with synthesis gas and a microbial culture solution, but it is not necessary to supply the synthesis gas and the microbial culture solution simultaneously; synthesis gas may be supplied to a microbial fermenter to which a microbial culture solution has already been supplied. It is known that certain anaerobic microorganisms produce ethanol and the like from substrate gases such as synthesis gas through fermentation, and these types of gas-assimilating microorganisms are cultured in a liquid medium. For example, a liquid medium and gas-assimilating bacteria may be supplied and housed in advance, and synthesis gas may be supplied into the microbial fermenter while stirring the liquid medium in this state. This allows the gas-assimilating bacteria to be cultured in the liquid medium, and ethanol to be produced from synthesis gas through the fermentation process.

[0072] In the microbial fermenter, the temperature of the medium etc. (culture temperature) may be any temperature, but is preferably about 30 to 45°C, more preferably about 33 to 42°C, and even more preferably about 36.5 to 37.5°C. The culture time is preferably 12 hours or more in continuous culture, more preferably 7 days or more, particularly preferably 30 days or more, and most preferably 60 days or more. There is no particular upper limit, but from the perspective of regular equipment maintenance, it is preferably 720 days or less, more preferably 365 days or less. The culture time means the time from when the seed bacteria is added to the culture tank until the entire culture medium in the culture tank is discharged.

[0073] The microorganisms (species) contained in the microbial culture solution are not particularly limited as long as they can produce ethanol by microbial fermentation of syngas using carbon monoxide as the main raw material. For example, the microorganisms (species) are preferably those that produce ethanol from syngas through the fermentation action of gas-utilizing bacteria, and are particularly preferably microorganisms that have a metabolic pathway for acetyl-COA. Among gas-utilizing bacteria, the genus Clostridium is more preferred, and Clostridium autoethanogenum is particularly preferred, but is not limited thereto. Further examples are provided below.

[0074] Gas-assimilating bacteria include both eubacteria and archaea. Examples of eubacteria include bacteria of the genus Clostridium, Moorella, Acetobacterium, Carboxydocella, Rhodopseudomonas, Eubacterium, Butyribacterium, Oligotropha, Bradyrhizobium, and the aerobic hydrogen-oxidizing bacteria of the genus Larsotonia.

[0075] 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.

[0076] Furthermore, due to their excellent ability to assimilate carbon monoxide and carbon dioxide, archaea are preferably bacteria of the genus Methanosarcina, Methanothermobactor, or Methanococcus, with Methanosarcina or Methanococcus being particularly preferred. Specific examples of Methanosarcina bacteria include Methanosarcina barkeri, Methanosarcina mazei, and Methanosarcina acetivorans.

[0077] Among the gas-utilizing bacteria described above, bacteria with a high ability to produce the target ethanol are selected and used. For example, gas-utilizing bacteria with a high ability to produce ethanol include Clostridium autoethanogenum, Clostridium Examples of the bacterium include Clostridium ljungdahlii, Clostridium aceticum, Clostridium carboxidivorans, Moorella thermoacetica, and Acetobacterium woodii, and among these, Clostridium autoethanogenum is particularly preferred.

[0078] The medium used to culture the above-mentioned microorganisms (species) is not particularly limited as long as it has an appropriate composition depending on the bacterium, but is a liquid containing water as the main component and nutrients (e.g., vitamins, phosphoric acid, etc.) dissolved or dispersed in the water. The composition of such a medium is prepared so that gas-assimilating bacteria can grow well. For example, when using the genus Clostridium as the microorganism, reference can be made to U.S. Patent Application Publication No. 2017 / 260552, paragraphs "0097" to "0099," etc., for the medium.

[0079] The ethanol-containing liquid obtained by the microbial fermentation process can be obtained as a suspension containing microorganisms, their carcasses, proteins derived from the microorganisms, etc. The protein concentration in the suspension varies depending on the type of microorganism, but is usually 30 to 1000 mg / L. The protein concentration in the ethanol-containing liquid can be measured by the Kjeldahl method.

[0080] <Separation process> The ethanol-containing liquid obtained by the microbial fermentation process is then subjected to a separation process. In the present invention, the ethanol-containing liquid is heated from 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 by the microbial fermentation process is distilled to separate and purify the desired ethanol. However, because the ethanol-containing liquid contains microorganisms and proteins derived from microorganisms, distilling the ethanol-containing liquid directly can cause foaming in the distillation apparatus, hindering continuous operation. Furthermore, while the use of a membrane evaporator is known as a method for purifying foamable liquids, membrane evaporators have low concentration efficiency and are not suitable for purifying liquids containing solid components. In the present invention, before separating and purifying the desired ethanol from the ethanol-containing liquid obtained by the microbial fermentation process by distillation or other procedures, 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 then separated and purified from only the separated gaseous component containing ethanol. By carrying out the separation step, foaming does not occur in the distillation apparatus during the distillation operation for separating and purifying ethanol, so that the distillation operation can be carried out continuously. Furthermore, since the ethanol concentration contained in the ethanol-containing gas component becomes higher than the ethanol concentration in the ethanol-containing liquid, ethanol can be separated and purified efficiently in the purification step described below.

[0081] In the present invention, from the viewpoint of efficiently separating the ethanol-containing liquid into a liquid or solid component containing microorganisms, their carcasses, proteins derived from microorganisms, etc., and 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, and even more preferably at normal pressure, at a temperature of preferably 50 to 200°C, more preferably at a temperature of 80 to 180°C, and even more preferably at a temperature of 100 to 150°C.

[0082] The heating time in the separation step is not particularly limited as long as it is a time that allows gas components to be obtained, but from the standpoint 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.

[0083] In the above-mentioned separation step, any device can be used without particular limitation as long as it can efficiently separate an ethanol-containing liquid into liquid or solid components (microorganisms, their carcasses, proteins derived from microorganisms, etc.) and a gaseous component (ethanol) using thermal energy. For example, drying devices such as a rotary dryer, a fluidized bed dryer, a vacuum dryer, and a conduction heating dryer can be used. However, from the viewpoint of efficiency in separating an ethanol-containing liquid with a low solid component concentration into a liquid or solid component and a gaseous component, it is preferable to use a conduction heating dryer. Examples of conduction heating dryers include a drum dryer and a disk dryer.

[0084] <Liquefaction process> The liquefaction step is a step of liquefying the gaseous components 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, particularly a condenser. Examples of condensers include water-cooled, air-cooled, and evaporative types, with water-cooled types being preferred. The condenser may be a single-stage or multi-stage type.

[0085] Although it is preferable that the liquefied product obtained by the liquefaction step does not contain components contained in the ethanol-containing liquid, such as microorganisms, their carcasses, proteins derived from microorganisms, etc., the present invention does not exclude the inclusion of proteins in the liquefied product. Even if the liquefied product contains proteins, the concentration of proteins is preferably 40 mg / L or less, more preferably 20 mg / L or less, and even more preferably 15 mg / L or less.

[0086] The heat of condensation of the gaseous components obtained by the condenser may be reused as a heat source in the purification step described below. By reusing the heat of condensation, ethanol can be produced efficiently and economically.

[0087] <Purification process> Next, ethanol is purified from the liquefied product obtained in the liquefaction step. If components such as microorganisms have already been removed, the ethanol-containing liquid obtained in the microbial fermentation step can be supplied to the purification step without undergoing the above-mentioned separation step. The purification step is a step in which the ethanol-containing liquid obtained in the liquefaction step is separated into a distillate having an increased concentration of the target ethanol and a bottoms liquid having a decreased concentration of the target ethanol. Examples of equipment used in the purification step include a distillation apparatus, a treatment apparatus including a pervaporation membrane, a treatment apparatus including a zeolite dehydration membrane, a treatment apparatus for removing low-boiling substances having a boiling point lower than that of ethanol, a treatment apparatus for removing high-boiling substances having a boiling point higher than that of ethanol, and a treatment apparatus including an ion exchange membrane. These apparatuses may be used alone or in combination of two or more. Thermal distillation or membrane separation may be suitably used as a unit operation.

[0088] In thermal distillation, a distillation apparatus is used to obtain the desired ethanol as a distillate with high purity. The temperature inside the distillation apparatus during ethanol distillation is not particularly limited, but is preferably 100°C or less, and more preferably about 70 to 95°C. By setting the temperature inside the distillation apparatus within the above range, separation of ethanol from other components, i.e., distillation of ethanol, can be more reliably performed. In particular, the ethanol-containing liquid obtained in the liquefaction step is introduced into a distillation apparatus equipped with a heater using steam at 100°C or higher, and the temperature of the bottom of the distillation column is raised to 90°C or higher within 30 minutes. The ethanol-containing liquid is then introduced from the middle of the distillation column, and the distillation step is performed with the temperature difference between the bottom, middle, and top of the column within ±15°C, thereby obtaining high-purity ethanol. The distillation temperature difference is preferably ±13°C, more preferably ±11°C. This distillation temperature difference allows separation from other components, i.e., distillation of ethanol, to be more reliably performed.

[0089] The pressure inside the distillation apparatus during ethanol distillation may be normal pressure, but is preferably less than atmospheric pressure, more preferably about 60 to 95 kPa (absolute pressure). By setting the pressure inside the distillation apparatus within this range, it is possible to improve the ethanol separation efficiency and, in turn, the ethanol yield. The ethanol yield (the concentration of ethanol in the distillate after distillation) is preferably 90% by volume or more, more preferably 95% by volume or more.

[0090] In membrane separation, a known separation membrane can be used as appropriate, and for example, a zeolite membrane can be suitably used.

[0091] The concentration of ethanol contained in the distillate separated in the purification step is preferably 20% by volume to 99.99% by volume, and more preferably 60% by volume to 99.9% by volume. On the other hand, the concentration of ethanol contained in the bottoms is preferably 0.001% to 10% by volume, and more preferably 0.01% to 5% by volume.

[0092] The bottoms separated in the purification step are substantially free of nitrogen compounds. In the present invention, "substantially free" does not mean that the nitrogen compound concentration is 0 mg / L, but rather that the bottoms obtained in the purification step have a nitrogen compound concentration low enough that a wastewater treatment step is not required. In the separation step, the desired ethanol is not purified from the ethanol-containing liquid obtained in the microbial fermentation step, but rather the ethanol-containing liquid is separated into a liquid or solid component containing microorganisms and a gaseous component containing ethanol, as described above. Since the nitrogen compounds remain in the liquid or solid component containing microorganisms, the gaseous component containing ethanol contains almost no nitrogen compounds. Therefore, the bottoms obtained when ethanol is purified from a liquefied product of the gaseous component are considered to be substantially free of nitrogen compounds. Even if the bottoms contain nitrogen compounds, the concentration of the 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.

[0093] For the same reasons as above, the bottoms separated in the purification step are substantially free of phosphorus compounds. Note that "substantially free" does not mean that the phosphorus compound concentration is 0 mg / L, but rather that the bottoms obtained in the purification step have a phosphorus compound concentration at a level that does not require a wastewater treatment process. Even if the bottoms contain phosphorus compounds, the phosphorus compound concentration 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 bottoms discharged in the ethanol purification step are considered to be substantially free of nitrogen compounds and phosphorus compounds and to contain almost no other organic matter, thereby simplifying the wastewater treatment process that was previously required.

[0094] <Wastewater treatment process> The bottoms separated in the refining step may be supplied to a wastewater treatment step. In the wastewater treatment step, organic matter such as nitrogen compounds and phosphorus compounds may be further removed from the bottoms. In this step, the bottoms may be subjected to anaerobic or aerobic treatment to remove the organic matter. The removed organic matter may be used as fuel (heat source) in the refining step.

[0095] The treatment temperature in the wastewater treatment step is usually 0 to 90°C, preferably 20 to 40°C, and more preferably 30 to 40°C.

[0096] The bottoms obtained through the separation process have liquid and solid components, including microorganisms, removed, and therefore require less wastewater treatment than bottoms obtained by directly supplying the bottoms from the microbial fermentation process to the purification process.

[0097] In the wastewater treatment step, the nitrogen compound concentration in the treated liquid obtained by treating the bottoms is preferably 0.1 to 30 mg / L, more preferably 0.1 to 20 mg / L, even more preferably 0.1 to 10 mg / L, and it is particularly preferred that the treated liquid contains no nitrogen compounds. The phosphorus compound concentration in the treated liquid is preferably 0.1 to 10 mg / L, more preferably 0.1 to 5 mg / L, even more preferably 0.1 to 1 mg / L, and it is particularly preferred that the bottoms contain no phosphorus compounds.

[0098] <Uses of ethanol> The ethanol of the present invention can be used as a raw material for producing various organic compounds. For example, the ethanol of the present invention can be used as a raw material for producing 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. Below, we will explain as examples a method for synthesizing butadiene and a method for producing polyethylene and polyester using the ethanol of the present invention as a raw material, but it goes without saying that the ethanol of the present invention can also be used as a raw material for other chemical products and polymers.

[0099] <Method for synthesizing butadiene> Butadiene is primarily produced by refining the C4 fraction, a by-product of synthesizing ethylene 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 technology to convert ethanol (ethanol derived from microbial fermentation) that is not derived from fossil fuels into 1,3-butadiene, instead of using petroleum-derived chemical raw materials. Known methods for synthesizing butadiene using ethanol derived from microbial fermentation as a raw material include a method using MgO as a catalyst, a method using a mixture of Al2O3 and ZnO, and a catalyst with a magnesium silicate structure. In addition to the above, other catalysts that can be used include vanadium, manganese, iron, cobalt, nickel, copper, zinc, gallium, niobium, silver, indium, and cerium.

[0100] By contacting the ethanol of the present invention with the above-mentioned catalyst 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 an ultimate resource-recycling society that is not dependent on petroleum resources.

[0101] The heating temperature for promoting the conversion reaction is, for example, about 300 to 450°C, preferably about 350 to 400°C, in the reaction system. If the temperature in the reaction system is below this range, the catalytic activity is insufficient, the reaction rate decreases, and the production efficiency tends to decrease. On the other hand, if the temperature in the reaction system exceeds this range, the catalyst may be easily deteriorated.

[0102] The reaction can be carried out by a conventional method such as a batch method, a semi-batch method, or a continuous method. When a batch or semi-batch method is used, the ethanol conversion rate can be increased. However, when the ethanol of the present invention is used, even when a continuous method is used, the ethanol can be converted more efficiently than conventional methods. The reason for this is not clear, but it is thought to be due to the presence of a unique peak in a gas chromatogram measured by gas chromatography-mass spectrometry in the ethanol derived from a recyclable resource, such as that of the present invention, which uses a gas containing carbon monoxide and hydrogen as a substrate, that is not observed in ethanol derived from fossil fuels.

[0103] Examples of methods for contacting the raw material with the catalyst include a suspension bed method, a fluidized bed method, and a fixed bed method. Either a gas phase method or a liquid phase method may be used. From the viewpoint of easy catalyst recovery and regeneration, it is preferable to use a fixed-bed continuous gas phase flow reactor in which the catalyst is packed into a reaction tube to form a catalyst layer, and the raw material is passed through as a gas to carry out the reaction in the gas phase. When carrying out the reaction 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 gas and then supplied to the reactor.

[0104] After the ethanol conversion reaction is completed, the reaction product (1,3-butadiene) can be separated and purified by a separation means such as filtration, concentration, distillation, extraction, or a combination of these.

[0105] <Polyethylene> The ethanol of the present invention can also be suitably used as a raw material for polyethylene, a versatile general-purpose plastic. Conventional polyethylene is produced by synthesizing ethylene from petroleum and polymerizing the ethylene monomer. By producing polyethylene using the ethanol of the present invention, it becomes possible to realize an ultimate resource-circulating society that is not dependent on petroleum resources.

[0106] First, ethylene, a raw material for polyethylene, is synthesized using the ethanol according to the present invention as a raw material. The method for producing ethylene is not particularly limited, and it can be obtained by a conventionally known method. As an example, ethylene can be obtained by the dehydration reaction of ethanol. A catalyst is usually used when obtaining ethylene by the dehydration reaction of ethanol, and this catalyst is not particularly limited, and a conventionally known catalyst can be used. From the viewpoint of process, a fixed-bed flow reaction is advantageous because it allows easy separation of the catalyst and the product, and for example, γ-alumina or the like is preferred.

[0107] 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 reaction rate, but is preferably 100°C or higher, 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.

[0108] The reaction pressure is not particularly limited, but a pressure equal to or higher than atmospheric pressure is preferred to facilitate subsequent gas-liquid separation. From an industrial perspective, a fixed-bed flow reaction is preferred because it facilitates catalyst separation, but a liquid-phase suspension bed, a fluidized bed, or the like may also be used.

[0109] 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 avoid water in terms of 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, particularly butene, produced. The allowable lower limit of the water content is 0.1% by mass or more, preferably 0.5% by mass or more. There are no particular limitations on the upper limit, but from the viewpoints of material 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.

[0110] By carrying out the dehydration reaction of ethanol as described above, a mixture of ethylene, water, and a small amount of unreacted ethanol is obtained. Since ethylene is in a gaseous state at room temperature below about 5 MPa, water and ethanol can be removed from this mixture by gas-liquid separation to obtain ethylene. This method can be carried out by any known method. The ethylene obtained by gas-liquid separation is then further distilled. There are no particular restrictions on the distillation method, operating temperature, residence time, etc., except that the operating pressure must be above atmospheric pressure.

[0111] Ethanol derived from recyclable resources using carbon monoxide and hydrogen-containing gas as a substrate, as in the present invention, exhibits a unique peak in a gas chromatograph measured by gas chromatography-mass spectrometry that is not observed 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, so they may be removed by purification. The purification method is not particularly limited, and conventionally known methods can be used. An example of a suitable purification procedure is adsorption purification. The adsorbent used is not particularly limited, and conventionally known adsorbents can be used. 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 preferable to perform it before adsorption purification. In this case, a water removal treatment is required after caustic treatment and before adsorption purification.

[0112] The polymerization method for the ethylene-containing monomer is not particularly limited, and can be carried out by a conventionally known method. The polymerization temperature and polymerization pressure can be adjusted appropriately depending on the polymerization method and polymerization apparatus. The polymerization apparatus is also not particularly limited, and a conventionally known apparatus can be used. An example of the polymerization method for the ethylene-containing monomer will be described below.

[0113] 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 desired, such as differences in density and branching, such as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE). 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 stage or two or more stages by any of gas-phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0114] The single-site catalyst 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 activating co-catalyst. Single-site catalysts are preferred because they have a more uniform active site structure than multi-site catalysts, making it possible to polymerize polymers with high molecular weights and highly uniform structures. Metallocene catalysts are particularly preferred as single-site catalysts. Metallocene catalysts are catalysts containing the following catalytic components: a transition metal compound of Group IV of the periodic table containing a ligand with a cyclopentadienyl skeleton, a co-catalyst, and optionally an organometallic compound and a carrier.

[0115] In the 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, or the like. The substituted cyclopentadienyl group has a substituent such as a hydrocarbon group having 1 to 30 carbon atoms. Examples of the transition metal include zirconium, titanium, and hafnium, with zirconium and hafnium being particularly preferred. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and it is preferred that the respective ligands having a cyclopentadienyl skeleton are bonded to each other by a bridging group. The above-mentioned transition metal compounds can be used as a catalyst component either alone or in combination of two or more.

[0116] The co-catalyst refers to a substance that can effectively make the above-mentioned transition metal compound function as a polymerization catalyst or that can balance the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes of organoaluminum oxy compounds and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of a cation with or without an active hydrogen group and a non-coordinating anion, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

[0117] The transition metal compounds described above may be used by being supported on an inorganic or organic carrier, preferably a porous oxide of an inorganic or organic compound, such as montmorillonite or other ion-exchangeable layered silicates, SiO2, Al2O3, MgO, ZrO2, TiO2, BO3, CaO, ZnO, BaO, ThO2, or mixtures thereof.

[0118] Further, as organometallic compounds that may be used if necessary, there may be mentioned organoaluminum compounds, organomagnesium compounds, organozinc compounds, etc. Of these, organoaluminum compounds are preferably used.

[0119] As the polyolefin, a polymer of ethylene or a copolymer of ethylene and an α-olefin may be used alone or in combination of two or more kinds.

[0120] <Acetaldehyde> Acetaldehyde is an important industrial chemical, useful as a raw material for, for example, acetic acid and ethyl acetate.

[0121] Acetaldehyde can be produced by oxidizing ethanol using a conventionally known method. 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 a concentration of approximately 100%, or may be 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 reaction efficiency. Ethanol and chlorine are preferably reacted at a supply rate of 25 to 100 sccm per 100 g of aqueous ethanol solution, for example.

[0122] The oxidation of ethanol with chlorine is preferably carried out using a chlorine-containing compound such as chlorine gas, hydrogen chloride, phosphorus pentachloride, phosphorus trichloride, phosphorus oxychloride, thionyl chloride, or a hypochlorous acid compound. This oxidation can be achieved, for example, by a photoreaction, a thermal reaction, or a catalytic reaction. Among these, photochlorination or thermal chlorination of ethanol with chlorine gas is preferred, and photochlorination with chlorine gas is more preferred. Photoreactions include irradiation with light of various wavelengths, such as ultraviolet light or visible light. Among these, irradiation with light from a light source having a wavelength of approximately 300 to 500 nm is preferred. The light source is not particularly limited, and examples include fluorescent lamps, mercury lamps, halogen lamps, xenon lamps, metal halide lamps, excimer lamps, and LED lamps. The reaction temperature is preferably approximately 0 to 80°C, and preferably approximately 0 to 50°C. The reaction time is preferably approximately 1 to 5 hours.

[0123] As another example, acetaldehyde can be produced by oxidizing ethanol in the gas phase in the presence of oxygen molecules and a catalyst. Examples of such catalysts include base metal oxides with gold particles dispersed and fixed therein. Examples of base metal oxides include La2O3, MoO3, Bi2O3, SrO, YO3, MgO, BaO, WO3, CuO, and composite oxides containing one or more of these.

[0124] The oxidation reaction of ethanol is carried out by contacting a gas containing ethanol and molecular oxygen with the catalyst at, for example, 100 to 280°C. The molecular oxygen used in the reaction may be supplied as oxygen gas or air. The raw material gas may contain a dilution gas (carrier gas) as needed. The reaction apparatus used in this reaction may be a typical apparatus typically used for gas-phase reactions. For example, a catalyst is filled into a reaction tube, the reaction tube is heated to a predetermined temperature, and a gas containing ethanol and oxygen gas or air is introduced into the reaction tube. The raw material gas is brought into contact with the catalyst, and the reaction gas is recovered. The reaction pressure may be atmospheric pressure, or may be increased to approximately 0.5 to 5 Pa (atmospheres) if necessary. Examples of dilution gases include so-called inert gases such as nitrogen, argon, helium, and carbon dioxide. The amount of dilution gas used may be determined appropriately taking into account the composition, flow rate, and reaction heat of the raw material gas, but is typically 1 to 100 times the volume of ethanol.

[0125] 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 in 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 if 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 practice, in relation to the gas flow rate, the space velocity (SV) is 10,000 to 40,000 h -1 ml g cat -1 It is preferable to use an amount that falls within the range of about 100%.

[0126] Furthermore, acetaldehyde can also be produced by dehydrogenating ethanol in the presence of a catalyst. For example, a solid catalyst containing copper as an active species can be used as such a catalyst. The copper as an active species may be in any form that has the activity of converting ethanol to acetaldehyde, such as metallic copper (element) or a copper compound (oxide, hydroxide, copper salt (inorganic acid salts such as copper sulfate, copper phosphate, copper nitrate, and copper carbonate; organic acid salts such as copper salts of carboxylic acids), 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. Copper may be used as metallic copper or a copper compound as is, or may be supported on a carrier. The copper as an active species may function as the main catalyst of the solid catalyst, and may be used in combination with a co-catalyst or the like. The solid catalyst may also be in a form in which both the copper and the co-catalyst are supported on a carrier.

[0127] The dehydrogenation reaction may be a liquid-phase reaction as long as ethanol is brought into contact with a solid catalyst. However, it is usually a gas-phase reaction in which gaseous ethanol is brought into contact with a solid catalyst in the gas phase. Considering the equilibrium between ethanol and acetaldehyde, catalyst life, and the like, the reaction temperature may be about 150 to 350°C, preferably about 170 to 300°C, and more preferably about 200 to 280°C. The higher the reaction temperature, the more the equilibrium shifts to acetaldehyde, thereby improving the conversion rate. The reaction may be carried out under pressure, but for convenience, it may also be carried out under normal pressure. It may also be carried out under reduced pressure, which is advantageous for the ethanol conversion rate.

[0128] <Acetic acid> Acetic acid is an important industrial chemical, useful as a raw material for, for example, vinyl acetate monomer, acetic anhydride, and acetate esters.

[0129] Acetic acid can be produced by oxidation of acetaldehyde by a conventional method. For example, acetic acid can be produced by air oxidation of acetaldehyde in the presence of a catalyst. Examples of the catalyst include manganese acetate and cobalt acetate.

[0130] <Ethyl t-butyl ether> Ethyl tert-butyl ether (ETBE) is an important chemical used as an industrial raw material. ETBE is useful, for example, as a gasoline substitute, especially as a premium fuel.

[0131] ETBE can be synthesized from ethanol and isobutene by a conventionally known method. For example, it can be produced by reacting ethanol and isobutene in the presence of a reaction catalyst. The molar ratio of isobutene to the raw material ethanol is preferably 0.1 to 10 moles, more preferably 0.5 to 2 moles.

[0132] As the reaction catalyst, a cation exchange resin is preferably used, and a strongly acidic cation exchange resin is more preferably used. As such a strongly acidic cation exchange resin, a porous type (MR type) styrene resin in which a strong acid group such as a sulfonic acid group (-SO3H) is introduced as an ion exchange group is preferred. The particle size of the strongly acidic cation exchange resin is preferably 0.5 to 1.0 mm. The amount of the 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.

[0133] The method of using the reaction catalyst is not particularly limited, and it can be used in the reaction in the form of a fixed bed, a fluidized bed, or a suspension bed. The reaction between isobutene and ethanol is not particularly limited, but a pressurized gas-liquid mixed phase reaction method, which can maintain the ethanol in a liquid phase, is preferred. This method further improves the yield of ETBE obtained.

[0134] <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 also be obtained from ethanol via ethylene. By producing polyethylene using the ethanol of the present invention, it is possible to realize an ultimate resource-recycling society that is not dependent on petroleum resources.

[0135] The polyester is composed of diol units and dicarboxylic acid units and is obtained by a polycondensation reaction using ethylene glycol as the diol units and terephthalic acid, isophthalic acid, or the like as the dicarboxylic acid units. Ethylene glycol is obtained from the ethanol of the present invention as a raw material, and can be obtained, for example, by converting ethanol into ethylene oxide using a conventionally known method to produce ethylene glycol.

[0136] Dicarboxylic acids can include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and derivatives thereof without limitation. Examples of aromatic dicarboxylic acids include terephthalic acid and isophthalic acid. Examples of aromatic dicarboxylic acid derivatives 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 an aromatic dicarboxylic acid. Examples of aliphatic dicarboxylic acids include linear or alicyclic dicarboxylic acids typically having 2 to 40 carbon atoms, such as oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, and cyclohexanedicarboxylic acid. Examples of aliphatic dicarboxylic acid derivatives include lower alkyl esters of the above aliphatic dicarboxylic acids, such as methyl esters, ethyl esters, propyl esters, and butyl esters, and cyclic acid anhydrides of the above aliphatic dicarboxylic acids, such as succinic anhydride. Among these, adipic acid, succinic acid, dimer acid, or a mixture thereof is preferred, and those containing succinic acid as the main component are particularly preferred. As the derivatives of aliphatic dicarboxylic acids, methyl esters of adipic acid and succinic acid, or a mixture thereof, are more preferred.

[0137] The polyester can be obtained by a conventionally known method of polycondensing the above-mentioned diol unit and dicarboxylic acid unit. Specifically, the polyester can be produced by a general melt polymerization method in which an esterification reaction and / or transesterification reaction between the above-mentioned dicarboxylic acid component and diol component is carried out, followed by a polycondensation reaction under reduced pressure, or by a known solution heating dehydration condensation method using an organic solvent.

[0138] The polycondensation reaction is preferably carried out in the presence of a polymerization catalyst, and examples of the polymerization catalyst include titanium compounds, zirconium compounds, and germanium compounds.

[0139] The reaction temperature for the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is usually in the range of 150 to 260° C., and the reaction atmosphere is usually an inert gas atmosphere such as nitrogen or argon.

[0140] In the polycondensation reaction step, a chain extender (coupling agent) may be added to the reaction system. After the polycondensation is completed, the chain extender is added to the reaction system in a homogeneous molten state without a solvent, and reacted with the polyester obtained by polycondensation.

[0141] After solidification, the obtained polyester may be subjected to solid-phase polymerization as necessary to further increase the degree of polymerization or to remove oligomers such as cyclic trimers.

[0142] In the production process of polyester, various additives may be added within the range that does not impair the properties of the polyester. For example, plasticizers, ultraviolet stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, friction reducers, release agents, antioxidants, ion exchange agents, color pigments, etc. may be added.

[0143] The ethanol produced by the present invention can be used as a raw material for not only the above-mentioned polymers but also various other polymers. Since the molded articles of the obtained polymers are carbon-neutral materials, it will be possible to realize an ultimate resource-circulating society that is not dependent on petroleum resources.

[0144] <Products containing ethanol> The ethanol of 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, sanitizers, cleaning agents, mold removers, detergents, hair washes, soaps, antiperspirants, facial cleansing sheets, solvents, paints, adhesives, diluents, and food additives. By using it in these applications, it can exhibit effects appropriate for each application.

[0145] <Fuel> The ethanol according to the present invention can also be used as a raw material for fuels (e.g., jet fuel, kerosene, diesel, gasoline), etc. Because ethanol has high bactericidal properties, it can also function as a disinfectant to prevent the proliferation of bacteria in fuel systems such as engines and piping.

[0146] The Japan Society of Automotive Engineers of Japan standard (2006) stipulates that the ethanol concentration in fuel ethanol must be 99.5% by volume or more. Other countries (e.g., India) also stipulate that the ethanol concentration in fuel ethanol must be 99.5% by volume or more. Therefore, ethanol with a purity of 99.5 to 99.9% by volume can be suitably used in dedicated ethanol vehicles. Furthermore, because fuel ethanol can be used for purposes other than dedicated ethanol vehicles, ethanol with a purity of 99.5 to 99.9% by volume is particularly versatile.

[0147] Furthermore, the ethanol of the present invention can be mixed with gasoline to produce ethanol-blended gasoline. Using ethanol-blended gasoline can reduce the environmental impact. The purity of the ethanol used in ethanol-blended gasoline is 92.0% by volume or more, preferably 95.0% by volume or more, and more preferably 99.5% by volume or more.

[0148] The ethanol content in ethanol-blended gasoline is preferably 1% by volume or more and 15% by volume or less, more preferably 2% by volume or more and 12% by volume or less, and even more preferably 3% by volume or more and 10% by volume or less. If the ethanol content is 1% by volume or more, the advantage of improving the octane number by blending ethanol can be obtained, and if it is 15% by volume or less, the evaporation characteristics will not change significantly due to the azeotropic phenomenon with other gasoline base stocks, and the appropriate drivability of gasoline-powered automobiles can be ensured.

[0149] The water content in the ethanol-blended gasoline is preferably 0.01% by mass or more and 0.9% by mass or less, 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 about 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 JIS K 2275, "Crude oil and petroleum products - Water content test method," for example, Karl Fischer coulometric titration can be used.

[0150] The gasoline base stock may be any commonly used gasoline base stock, and is not particularly limited. Examples of gasoline base stocks include light naphtha obtained by atmospheric distillation of crude oil, preferably desulfurized light naphtha obtained by desulfurizing it, catalytic reformate obtained by desulfurizing heavy naphtha and then catalytic reforming it, and benzene-free catalytic reformate obtained by treating it with benzene, benzene-free light catalytic reformate, benzene-free heavy catalytic reformate, 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.

[0151] Furthermore, the ethanol-based ETBE of the present invention can be blended with gasoline to produce ETBE-blended gasoline. Using ETBE-blended gasoline reduces the environmental impact. The ETBE content of ETBE-blended gasoline is preferably 1% by volume or more and 15% by volume or less, more preferably 2% by volume or more and 12% by volume or less, and even more preferably 3% by volume or more and 10% by volume or less. An ETBE content of 1% by volume or more provides the benefit of improving the octane number by blending ETBE, while a content of 15% by volume or less prevents significant changes in evaporation characteristics due to the azeotropic phenomenon with other gasoline base stocks, ensuring the appropriate drivability of gasoline-powered automobiles. [Example]

[0152] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[0153] <Evaluation method for ethanol component> In the following examples and comparative examples, the content of chromium in ethanol was measured using an inductively coupled plasma mass spectrometer (ICP-MS) ELAN DRCII manufactured by PerkinElmer.

[0154] <Quantification method for butadiene> The quantitative evaluation of butadiene was performed by analysis using a gas chromatography apparatus (GC-2014, manufactured by SHIMADZU). The measurement conditions were as follows. <Analysis conditions for 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 / min → 100 °C for 14.5 minutes → 10 °C / min → 250 °C Sampling time: 5 minutes Carrier gas: He (30 cm / s) Split ratio: 75

[0155] <Quantification method for 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 for GC / MS method> Column: DB-1 (length 30.0 m, inner diameter 0.254 mm, film thickness 0.25 m) Temperature rising condition: 30 °C - 300 °C at 15 °C / min Carrier gas: He 100 kPa Split ratio: 50

[0156] <Quantification method for combustion efficiency> The quantitative evaluation of ethanol combustion efficiency was carried out by gross calorific value analysis using a cone calorimeter manufactured by FTT.

[0157] [Example 1] <Preparation of ethanol> Ethanol was produced as follows. (raw material gas generation process) The gas used was the gas emitted after incineration of municipal waste in a waste incineration facility. The raw gas consisted of approximately 30% by volume of carbon monoxide, 30% by volume of carbon dioxide, 30% by volume of hydrogen, and 10% by volume of nitrogen.

[0158] (Synthetic gas refining process) The raw material gas produced as described above was heated to 80°C using a PSA unit, an impurity removal unit, and the carbon dioxide contained in the synthesis gas was removed to 60 to 80% by volume of the original content (approximately 30% by volume).The gas was then heated in a double-pipe heat exchanger using steam at 150°C and re-cooled in another double-pipe heat exchanger using cooling water at 25°C, causing the impurities to precipitate, which were then removed using a filter, thereby producing synthesis gas.

[0159] (Microbial fermentation process) The synthesis gas obtained as described above was continuously supplied to a continuous fermentation apparatus (microbial fermentation tank) equipped with a main reactor, synthesis gas inlet, and outlet, and filled with a Clostridium autoethanogenum (microorganism) seed culture and a liquid culture medium (containing appropriate amounts of phosphorus compounds, nitrogen compounds, and various minerals). Cultivation (microbial fermentation) was carried out continuously for 300 hours. After that, approximately 8,000 L of the ethanol-containing culture medium was withdrawn from the outlet.

[0160] (separation process) The culture solution obtained in the above fermentation step was subjected to a solid-liquid separation filter device under a culture solution inlet pressure of 200 kPa or more to obtain an ethanol-containing solution.

[0161] (Distillation process) The ethanol-containing liquid was then introduced into a distillation apparatus equipped with a heater using 170°C steam. After the temperature at the bottom of the distillation column was raised to 101°C within 8 to 15 minutes, the ethanol-containing liquid was introduced into the middle of the distillation column. During continuous operation, the column bottom was kept at 101°C, the middle at 99°C, and the top at 91°C, and the distillation rate was 15 sec / L to obtain purified ethanol. The chromium content in the obtained ethanol was less than 0.5 mg / L.

[0162] (Butadiene manufacturing method) Butadiene was produced using the ethanol obtained as described above. First, the obtained ethanol was vaporized through a single tube heated to 90°C to prepare a gas for reaction. The vaporized ethanol gas was then combined with nitrogen. The mass flow was controlled to set the ethanol gas flow rate at 360 L / hr / L and the nitrogen flow rate at 840 L / hr / L, producing a mixed gas of 30% by volume (gas equivalent) ethanol and 70% by volume (gas equivalent) nitrogen. Next, the mixed gas was continuously supplied to a stainless steel cylindrical reaction tube, 1 / 2 inch (1.27 cm) in diameter and 15.7 inches (40 cm) long, packed with 0.85 g of a butadiene synthesis catalyst primarily composed of Hf, Zn, and Ce, while maintaining the temperature at 350°C and the pressure (reaction bed pressure) at 0.1 MPa, to produce a butadiene-containing gas. The butadiene content of the obtained butadiene-containing gas was quantified using a gas chromatography system GC-2014 (manufactured by Shimadzu Corporation). The results are shown in Table 1.

[0163] [Comparative Example 1] Butadiene was produced in the same manner as in Example 1 using 99% ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.), which is fossil fuel-derived ethanol, and the butadiene content was quantified in the same manner as in Example 1. The results are shown in Table 1. The chromium content in the 99% ethanol, which is fossil fuel-derived ethanol, was 0.7 mg / L.

[0164] Comparative Example 2 Butadiene was produced in the same manner as in Example 1 using 99% ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.) derived from the saccharification and fermentation of plants, and the butadiene content was quantified in the same manner as in Example 1. The results are shown in Table 1. The chromium content in the 99% ethanol derived from the saccharification and fermentation of plants was 0.7 mg / L.

[0165] [Table 1]

[0166] As shown in Table 1, ethanol produced using the gas emitted after incineration of municipal waste in waste incineration facilities was found to have a higher conversion efficiency to butadiene than ethanol derived from conventional fossil fuels or ethanol derived from saccharification and fermentation of plants.

[0167] [Example 2] (Production of ethyl benzoate) Ethyl benzoate was produced using the same ethanol as used in Example 1 as follows. First, 36.8 g of benzoic acid and 200 ml of ethanol were mixed under an argon atmosphere, 9 ml of concentrated sulfuric acid was added, and the mixture was stirred under reflux for 5 hours. The mixture was then allowed to cool to room temperature, and unreacted ethanol was removed under reduced pressure. The synthesized ethyl benzoate was recovered using 100 ml of diethyl ether. The recovered solution was washed with distilled water, dried over magnesium sulfide, and then filtered and concentrated. The obtained filtrate was subjected to component analysis using a gas chromatograph 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 30.0 m, inner diameter 0.254 mm, film thickness 0.25 m) Temperature rise conditions: 30-300℃ 15℃ / min Carrier gas: He 100kPa Split ratio: 50

[0168] Comparative Example 3 Ethyl benzoate was produced and quantified in the same manner as in Example 2, except that the petrochemical-derived ethanol used in Comparative Example 1 was used. The analytical results are shown in Table 2.

[0169] Comparative Example 4 Ethyl benzoate was produced and quantified in the same manner as in Example 2, except that the petrochemical-derived ethanol used in Comparative Example 2 was used. The analytical results are shown in Table 2.

[0170] [Table 2]

[0171] As shown in Table 2, ethanol produced using the gas emitted after incineration of municipal waste in waste incineration facilities was found to have a higher conversion efficiency to ethyl benzoate than ethanol derived from conventional fossil fuels or ethanol derived from saccharification and fermentation of plants.

[0172] [Example 3] The combustion efficiency of ethanol was quantified using the same ethanol as used in Example 1. The fuel efficiency was quantified by placing 30 g of ethanol in a heat-resistant container measuring 60 mm long x 60 mm wide x 30 mm high under unheated conditions, igniting it, measuring the amount of oxygen lost until the ethanol was completely burned 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.

[0173] 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 quantification results are shown in Table 3.

[0174] 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 quantification results are shown in Table 3.

[0175] [Table 3]

[0176] As shown in Table 3, ethanol produced using the gas emitted after incineration of municipal waste in waste incineration facilities has higher combustion efficiency than ethanol derived from conventional fossil fuels or ethanol derived from saccharification and fermentation of plants.

Claims

1. a step of producing a raw material gas containing carbon monoxide and hydrogen by gasifying waste as a carbon source; a step of purifying the raw material gas using at least one type of separation device selected from pressure swing adsorption, temperature swing adsorption, and pressure temperature swing adsorption to obtain a synthesis gas containing carbon monoxide and hydrogen; a microbial fermentation step of supplying the synthesis gas to a fermenter containing Clostridium bacteria as microorganisms to obtain an ethanol-containing liquid by microbial fermentation; a separation step of separating the ethanol-containing liquid into microorganisms and / or proteins derived from the microorganisms, and ethanol; and a purification step of purifying the ethanol composition, A waste-derived ethanol composition having a chromium content of 0.6 mg / L or less.

2. A waste-derived ethanol composition obtained by a method comprising: a step of producing a raw material gas containing carbon monoxide and hydrogen by gasifying waste as a carbon source; a step of purifying the raw material gas using at least one type of separation device selected from pressure swing adsorption, temperature swing adsorption, and pressure temperature swing adsorption to obtain a synthesis gas containing carbon monoxide and hydrogen; a microbial fermentation step of supplying the synthesis gas to a fermenter containing Clostridium bacteria as microorganisms to obtain an ethanol-containing liquid by microbial fermentation; and a purification step of purifying the ethanol-containing liquid after removing the microorganisms, A waste-derived ethanol composition having a chromium content of 0.6 mg / L or less.

3. generating a raw material gas containing carbon monoxide and hydrogen by gasifying waste as a carbon source; purifying the feed gas using at least one separation device of a pressure swing adsorption type, a temperature swing adsorption type, or a pressure temperature swing adsorption type to obtain a synthesis gas containing carbon monoxide and hydrogen; a microbial fermentation step of supplying the synthesis gas to a fermenter containing Clostridium bacteria as microorganisms and obtaining an ethanol-containing liquid by microbial fermentation; a separation step of separating the ethanol-containing liquid into microorganisms and / or proteins derived from microorganisms, and ethanol; a purification step of purifying the ethanol composition; Including, The method for producing a waste-derived ethanol composition, wherein the purified ethanol composition has a chromium content of 0.6 mg / L or less.

4. generating a raw material gas containing carbon monoxide and hydrogen by gasifying waste as a carbon source; purifying the feed gas using at least one separation device of a pressure swing adsorption type, a temperature swing adsorption type, or a pressure temperature swing adsorption type to obtain a synthesis gas containing carbon monoxide and hydrogen; a microbial fermentation step of supplying the synthesis gas to a fermenter containing Clostridium bacteria as microorganisms and obtaining an ethanol-containing liquid by microbial fermentation; a purification step of purifying the ethanol-containing liquid after removing the microorganisms; Including, The method for producing a waste-derived ethanol composition, wherein the purified ethanol composition has a chromium content of 0.6 mg / L or less.

5. The ethanol composition according to claim 1 or 2, which is for use in chemical products.

6. The ethanol composition according to claim 1 or 2, which is for use as a fuel.

7. The ethanol composition according to claim 1 or 2, which is used as a polymer raw material.

8. A chemical product made from the ethanol composition according to claim 1 or 2 as a raw material.

9. A fuel comprising the ethanol composition according to claim 1 or 2 and / or ethyl t-butyl ether produced from the ethanol composition according to claim 1 or 2 as a raw material.

10. A polymer raw material obtained from the ethanol composition according to claim 1 or 2.

11. 11. The polymeric feedstock of claim 10, selected from the group consisting of ethylene, propylene, butadiene, ethyl acetate, isobutene, methyl (meth)acrylate, acrylic acid, aminohexanoic acid, and diethyl carbonate.

12. A polymer obtained from the polymer raw material according to claim 10 or 11.

13. A molded article made from the polymer of claim 12.

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