Organic substance production apparatus and organic substance production method

Abstract

An organic substance production apparatus 10 comprises: a gas generation unit 11 that generates a material gas containing carbon monoxide, carbon dioxide, and hydrogen; an organic substance generation unit 50 to which the material gas is supplied and which generates an organic substance from the material gas; a first temperature adjustment unit 20 that adjusts the temperature of the material gas emitted from the gas generation unit 11 to a temperature range of 350-550°C; a dust removal unit 30 that includes a dust collection device; and a second temperature adjustment unit 40 that adjusts the temperature of the material gas to 200°C or lower. The first temperature adjustment unit 20, the dust removal unit 30, and the second temperature adjustment unit 40 are arranged between the gas generation unit 11 and the organic substance generation unit 50 in the stated order from the upstream side.

Description

Organic substance manufacturing apparatus and organic substance manufacturing method

[0001] The present invention relates to an organic substance production apparatus and an organic substance production method for producing an organic substance from a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen.

[0002] In waste treatment facilities, it is common to gasify waste in a gasifier and combust the synthesis gas obtained by gasification at the outlet of the gasifier. However, in recent years, there has been a demand for producing chemical products from waste in order to contribute to a resource-recycling society. Accordingly, it has been considered to purify the synthesis gas obtained from waste and introduce it into a chemical production process. For example, Patent Document 1 considers converting the synthesis gas obtained from waste into organic compounds such as ethanol using gas-utilizing bacteria.

[0003] Since the synthesis gas obtained by gasifying waste in a gasifier is high in temperature and contains a large amount of impurities, purification and temperature reduction are necessary in order to convert it into organic compounds using gas-assimilating bacteria. For example, Patent Document 1 describes a method in which synthesis gas produced in a gasifier and reformed in a reformer is cooled to 200°C or less in a heat exchanger such as a boiler and a gas cooling tower, and then passed through a filter-type dust collector, scrubber, etc. to remove impurities before being brought into contact with gas-assimilating microorganisms.

[0004] International Publication No. 2021 / 193573

[0005] However, since the synthesis gas obtained from waste contains large amounts of impurities such as soot and tar, when the high-temperature synthesis gas is cooled to a low temperature using a gas cooling tower, a large amount of soot and tar gets mixed into the cooling water of the gas cooling tower. This makes the piping of the water circulation system and drainage system prone to blockage, necessitating frequent equipment maintenance. Furthermore, since a large amount of soot and tar gets mixed into the cooling water, a large-scale wastewater treatment system is required.

[0006] Therefore, an object of the present invention is to provide an organic substance production apparatus and an organic substance production method that can efficiently produce organic substances from a raw material gas containing carbon monoxide, hydrogen, and carbon dioxide by efficiently removing impurities while regulating the temperature, without requiring frequent equipment maintenance or large-scale wastewater treatment equipment.

[0007] As a result of extensive investigation, the present inventors have found that the above-mentioned problems can be solved by arranging a first temperature adjustment section, a dust removal section, and a second temperature adjustment section in this order between a gas generation section and the organic substance generation section, and adjusting the temperature of the raw material gas within a predetermined range in each temperature adjustment section, and have completed the present invention as described below. That is, the present invention provides the following [1] to

[10] .

[0008] [1] An organic substance production apparatus comprising: a gas generation unit that generates a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen; an organic substance production unit that receives the raw material gas and generates an organic substance from the raw material gas; a first temperature adjustment unit that adjusts the temperature of the raw material gas discharged from the gas generation unit to a range of 350°C to 550°C; a dust removal unit that includes a dust collector; and a second temperature adjustment unit that adjusts the temperature of the raw material gas to 200°C or less, wherein the first temperature adjustment unit, the dust removal unit, and the second temperature adjustment unit are arranged in this order from upstream to downstream between the gas generation unit and the organic substance production unit. [2] The organic substance production apparatus described in [1] above, which comprises a gas holder upstream of the organic substance production unit. [3] The organic substance production apparatus described in [1] or [2] above, wherein the dust collection unit includes at least one of a filter-type dust collector and a multi-cyclone. [4] The organic substance production apparatus according to any one of [1] to [3] above, wherein the first temperature adjustment unit includes at least one of a boiler and a desuperheater. [5] The organic substance production apparatus according to any one of [1] to [4] above, wherein the second temperature adjustment unit includes a scrubber. [6] The organic substance production apparatus according to any one of [1] to [5] above, wherein the gas generation unit generates the raw material gas from waste. [7] The organic substance production apparatus according to any one of [1] to [6] above, wherein the organic substance generation unit generates the organic substance by the action of gas-assimilating bacteria. [8] The organic substance production apparatus according to any one of [1] to [7] above, wherein the first temperature adjustment unit is a first temperature reduction unit that reduces the temperature of the raw material gas to within a range of 350°C to 550°C, and the second temperature adjustment unit is a second temperature reduction unit that reduces the temperature of the raw material gas to 200°C or less. [9] A method for producing an organic substance, comprising: generating a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen; treating the generated raw material gas in the following order at least: adjusting the temperature of the raw material gas to a range of 350°C or more and 550°C or less; passing the raw material gas through a dust removal section; and adjusting the temperature of the raw material gas to 200°C or less; and producing an organic substance from the treated raw material gas.

[10] The organic substance production method described in [9] above, wherein the step of adjusting the temperature to within the range of 350°C or higher and 550°C or lower is a step of reducing the temperature to within the range of 350°C or higher and 550°C or lower, and the step of adjusting the temperature to 200°C or lower is a step of reducing the temperature to 200°C or lower.

[0009] According to the present invention, an organic substance production apparatus and an organic substance production method are provided that can efficiently produce organic substances from raw material gases without requiring frequent equipment maintenance or large-scale wastewater treatment facilities.

[0010] It is a block diagram showing an organic substance producing apparatus according to a first embodiment. It is a schematic diagram showing an example of a scrubber used in a second temperature reducing section (second temperature adjusting section). It is a block diagram showing an organic substance producing apparatus according to a second embodiment.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same parts are denoted by the same reference numerals.

[0012] [First Embodiment] As shown in FIG. 1 , an organic substance production apparatus 10 according to a first embodiment of the present invention includes a gas generation unit 11 that generates a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen, and an organic substance production unit 50 that receives the raw material gas generated in the gas generation unit 11 and generates an organic substance from the raw material gas. The organic substance production apparatus 10 also includes a first temperature control unit 20, a dust removal unit 30, and a second temperature control unit 40, arranged in this order from upstream to downstream, between the gas generation unit 11 and the organic substance production unit 50. The raw material gas generated in the gas generation unit 11 passes through the first temperature control unit 20, the dust removal unit 30, and the second temperature control unit 40, in this order, where it is temperature-adjusted and purified before being supplied to the organic substance production unit 50. In this specification, the terms "upstream" and "downstream" refer to upstream and downstream along the raw material gas supply flow. The "supply flow" of the raw material gas refers to the flow of the raw material gas generated in the gas generation unit until it is introduced into the organic substance production unit.

[0013] <Gas Generating Unit> The gas generating unit 11 gasifies waste to generate a raw material gas. The waste may be industrial waste such as industrial solid waste or general waste such as municipal solid waste (MSW), and may include combustible materials such as plastic waste, food waste, discarded tires, biomass waste, food waste, construction materials, wood, wood chips, fiber, and paper.

[0014] When the calorific value of the waste is low, fossil fuel (LNG, LPG, etc.) may be added to the gas generating section 11 as a combustion aid in addition to the waste.

[0015] The gas generation unit 11 includes a gasifier 12 and a reformer 13. The gasifier 12 is a device that generates waste-derived pyrolysis gas by burning or pyrolyzing waste. Examples of the gasifier 12 include, but are not limited to, a fixed-bed gasifier such as a shaft furnace, a kiln gasifier, a fluidized-bed gasifier, and a plasma gasifier. In addition to the waste, oxygen or air, and optionally steam, are also fed into the gasifier 12. The addition of steam contributes to improving tar reforming or gasification efficiency. The gasifier 12 pyrolyzes and gasifies the waste in an atmosphere of, for example, 500°C or higher. The pyrolysis gas includes not only carbon monoxide, hydrogen, and carbon dioxide, but also tar, soot, char, and the like. The pyrolysis gas is supplied to the reformer 13. Solids generated as non-combustible materials in the gasifier 12 are appropriately recovered.

[0016] In the reformer 13, the pyrolysis gas obtained in the gasifier 12 is reformed, increasing the content of at least one of hydrogen and carbon monoxide in the pyrolysis gas, which is then discharged as a raw material gas. In the reformer 13, for example, tar and char contained in the pyrolysis gas are reformed into hydrogen and carbon monoxide. The temperature near the gas outlet in the reformer 13 is not particularly limited, but is, for example, 900°C or higher, preferably 1,000°C to 1,400°C, and more preferably 1,100°C to 1,300°C. By maintaining the temperature in the reformer 12 within the above range, a raw material gas with a high content of carbon monoxide and hydrogen is easily obtained. Furthermore, although dioxin precursors (e.g., chlorides having a benzene ring) are generated in the gasifier, they are thermally decomposed in the reformer, thereby suppressing dioxin resynthesis downstream. Furthermore, by setting the temperature at or above the lower limit, a sufficient reforming effect can be obtained, while by setting the temperature at or below the upper limit, mechanical durability can be maintained.

[0017] The temperature of the raw material gas discharged from the reformer 13 (i.e., the gas generation section 11) and supplied to the temperature adjustment section (temperature reduction section) 20 described later is generally similar to the temperature near the gas outlet in the reformer 13, and is, for example, 900°C or higher, preferably 1,000°C or higher and 1,400°C or lower, and more preferably 1,100°C or higher and 1,300°C or lower.

[0018] The raw material gas discharged from the reformer 13 (i.e., the gas generation section 11) is a so-called synthesis gas, and as described above, contains carbon monoxide, hydrogen, and carbon dioxide. The raw material gas discharged from the reformer 13 may contain, for example, 5% by volume or more of carbon monoxide, 5% by volume or more of hydrogen, and 5% by volume or more of carbon dioxide. The carbon monoxide concentration discharged from the reformer 13 is preferably 10% by volume or more and 75% by volume or less, more preferably 20% by volume or more and 70% by volume or less. The hydrogen concentration is preferably 10% by volume or more and 60% by volume or less, more preferably 20% by volume or more and 50% by volume or less. The carbon dioxide concentration is preferably 30% by volume or less.

[0019] The raw material gas discharged from the reformer 13 may contain nitrogen, oxygen, and the like in addition to hydrogen, carbon monoxide, and carbon dioxide. The nitrogen concentration in the raw material gas is usually 40% by volume or less, and preferably 20% by volume or less. The oxygen concentration in the raw material gas is usually less than 5% by volume, taking into account the explosion limit concentration of hydrogen in the gas. The lower the oxygen concentration, the better. However, oxygen is generally inevitably contained in many cases, and the oxygen concentration is substantially 0.01% by volume or more.

[0020] The concentrations of carbon monoxide, carbon dioxide, hydrogen, nitrogen, and oxygen in the feed gas can be kept within a predetermined range by appropriately changing the type of waste, the temperatures of the gasifier 12 and the reformer 13, the amount and concentration conditions of oxygen or steam as a gasifying agent supplied to the gasifier 12, or by adding fossil fuels (LNG, LPG, etc.). For example, if it is desired to increase the carbon monoxide and hydrogen concentrations, the gasification temperature can be raised by supplying more oxygen or the like to increase the combustion reaction (oxidation reaction) with the feed. Furthermore, if it is desired to decrease the nitrogen concentration, a method can be used in which a gasifying agent with a high oxygen concentration is used instead of air-blowing gasification in which air is used as the gasifying agent in the gasifier 12. The volume percentages of each substance in the feed gas mentioned above refer to the volume percentages of each substance in the feed gas discharged from the gas generation unit 11, i.e., the reformer 13.

[0021] The raw material gas discharged from the reformer 13 contains soot, char, tar, and the like. The tar contained in the raw material gas reformed in the reformer 13 is, for example, so-called polycyclic aromatic hydrocarbons. Specific examples of polycyclic aromatic hydrocarbons include naphthalene (boiling point 218°C), acenaphthylene (boiling point 280°C), acenaphthene (boiling point 279°C), fluorene (boiling point 295°C), anthracene (boiling point 342°C), phenanthrene (boiling point 340°C), fluoranthene (boiling point 375°C), and pyrene (boiling point 404°C). As described below, the tar contained in the raw material gas passes through the first temperature adjustment section (first temperature reduction section) 20 and the dust removal section 30 in a gaseous state, but is condensed in the second temperature adjustment section (second temperature reduction section) 40, which has a temperature lower than the boiling point temperature, and is removed in the second temperature adjustment section (second temperature reduction section) 40. In this specification, "removal" means reducing the concentration of the target substance in the gas by removing at least a portion of the target substance from the gas, and is not limited to completely removing the target substance.

[0022] Furthermore, in the above description, the gas generation unit 11 has been described as including the gasification furnace 12 and the reformer 13. However, the gas generation unit 11 is not limited to this as long as it has at least a gasification furnace and is capable of generating a raw material gas containing carbon monoxide, carbon dioxide, and hydrogen. The gas generation unit 11 does not necessarily require the gasification furnace and the reformer to exist separately, and may be an apparatus in which the gasification furnace 12 and the reformer 13 are integrated. In other words, if the gas generation unit 11 includes a gasification region and a region in which the generated gas generated in the gasification region is reformed, it is considered to include the gasification furnace 12 and the reformer 13. For example, if a shaft furnace or the like is used as the gasification furnace 12, the gas generation unit 11 may be an apparatus in which the gasification furnace 12 and the reformer 13 are integrated.

[0023] <First Temperature Adjustment Unit> The raw material gas generated in the gas generation unit 11 passes through the first temperature adjustment unit 20, the dust removal unit 30, and the second temperature adjustment unit 40 in this order. The first temperature adjustment unit 20 preferably adjusts the temperature of the raw material gas discharged from the gas generation unit 11 to a temperature range of 350°C to 550°C, but is preferably a temperature reduction unit that reduces the temperature of the raw material gas discharged from the gas generation unit 11 to a temperature range of 350°C to 550°C. The first temperature adjustment unit being a temperature reduction unit is preferable because it indicates that the temperature of the gas generated in the gas generation unit is high and in a reformed state. Note that in the following description, an embodiment in which the first temperature adjustment unit is a temperature reduction unit will be described, and the first temperature adjustment unit may also be referred to as the first temperature reduction unit. The raw material gas is then supplied to the dust removal unit 30 in a state in which its temperature has been adjusted to a temperature range of 350°C to 550°C.

[0024] As described above, the raw material gas reformed in the reformer furnace 13 contains tar (particularly polycyclic aromatic hydrocarbons), and the boiling point of these tars is approximately 200 to 400°C. Therefore, by heating the raw material gas to 350°C or higher in the first temperature reducing section (first temperature adjusting section) 20 and then passing it through the dust removing section 30, the contained tar reaches a temperature above the dew point, and the raw material gas can pass through the first temperature reducing section (first temperature adjusting section) 20 and the dust removing section 30 without condensing much therein. This prevents condensed tar from adhering to the first temperature reducing section (first temperature adjusting section) 20 and the dust removing section 30, thereby reducing the frequency of maintenance of the first temperature reducing section (first temperature adjusting section) 20 and the dust removing section 30. Furthermore, liquid tar remaining in the gas adheres to the dust collected in the dust removing section 30, and this liquid tar can also be removed from the gas by dust removal. Furthermore, by setting the temperature to 350° C. or higher, the risk of dioxin resynthesis can be reduced. Also, by reducing the temperature of the raw material gas to 550° C. or lower in the first temperature reducing section 20, the high-temperature raw material gas is prevented from passing through the dust removing section 30, reducing the heat resistance of the devices that make up the dust removing section 30 and maintaining the robustness of the dust removing section 30.

[0025] In the first temperature reducing section 20, the temperature of the raw material gas is preferably reduced to 350° C. or higher and 550° C. or lower, and more preferably 400° C. or higher and 450° C. or lower. The raw material gas is then supplied to the dust removing section 30 in a state where it has been reduced in temperature, preferably to a temperature range of 350° C. or higher and 550° C. or lower, more preferably to a temperature range of 400° C. or higher and 450° C. or lower. This is because if the temperature exceeds 550° C., the heat resistance of the metal structure of the dust removing section becomes poor, and if the temperature drops below 350° C., resynthesis of dioxin precursors that may be contained in the dust may be promoted.

[0026] In this embodiment, the first temperature reducing section 20 may be configured as a boiler. By passing the raw gas (gasification gas) through the boiler, heat exchange occurs with the boiler's heat transfer section, converting the water flowing therethrough into steam or superheating the steam, while simultaneously cooling the raw gas. Using a boiler as the first temperature reducing section 20 allows heat recovery from the high-temperature raw gas and effectively utilizing the thermal energy of the raw gas, such as easily heating other devices with the generated steam. Specifically, the steam generated in the boiler is supplied to the separation device 55 (described later) via a thermal energy path 25 connecting the first temperature reducing section 20 and the separation device 55, where it is used to purify organic substances. Furthermore, maintaining the first temperature reducing section 20 at or above the saturation temperature prevents impurities, such as soot and tar, contained in the raw gas from migrating into the cooling water, which can lead to contaminated wastewater or blockages in the circulating water system. This reduces the frequency of maintenance for this section. Furthermore, the first temperature reducing section 20 also reduces the wastewater treatment load containing soot and tar.

[0027] <Dust Removal Section> The dust removal section 30 removes solid matter contained in the raw gas that has passed through it. Specifically, soot and char are mainly removed in the dust removal section 30. The dust removal section 30 is not particularly limited as long as it can remove soot, char, and the like, and a dust collector may be used. However, a device that removes solid matter in a dry state is preferred, and a filter-type dust collector such as a filter is more preferred. The filter is preferably a dry filter. A dry filter is preferred because it can suppress wastewater contamination and reduce wastewater treatment costs. The reason for the reduced wastewater costs is that, in wet methods using water, soot and dust are mixed into the water during the dust removal process, making wastewater treatment complex and expensive. Therefore, using a dry filter can reduce the soot and dust contained in the wastewater, contributing to reduced wastewater costs.

[0028] The filter may include a filter material capable of capturing solid substances such as soot and char contained in the source gas, and a casing for housing the filter material. In this embodiment, a heat-resistant filter material is preferably used. Specifically, a ceramic filter using ceramic as the filter material or a metal filter using metal as the filter material is preferred. As described above, high-temperature gas in the range of 350 to 550°C is supplied to and passes through the dust removal unit 30. Using a heat-resistant filter material such as ceramic enables the filter-type dust collector to be used continuously for a long period of time. The ceramic filter preferably has excellent thermal shock resistance. Examples of ceramic filters with excellent thermal shock resistance include ceramic-coated cloth filters. As described above, filters with excellent thermal shock resistance, such as ceramic-coated cloth filters, can suppress the occurrence of cracks that can occur due to repeated deformation caused by repeated thermal expansion and contraction, thereby improving durability. Furthermore, it is preferred that only the ends of the ceramic filter are fixed. Examples of filters with only the ends fixed include hanging and candle-type filters. By using a hanging type as described above, the ceramic filter can be designed to be less likely to come off. The mesh size of the ceramic filter is, for example, 1 μm or more and 100 μm or less, preferably 1 μm or more and 50 μm or less, and more preferably 1 μm or more and 10 μm or less. When the mesh size is within the above range, dust can be collected efficiently and pressure loss can be reduced. Furthermore, passing the dust through the filter at a temperature of 350° C. or more is preferable because the viscosity of organic substances contained in the dust is less likely to increase, making the filter less likely to clog.

[0029] The dust removal unit 30 may be a device other than a filter-type dust collector, for example, a multi-cyclone. A multi-cyclone is a device with multiple cyclones arranged in parallel. Each cyclone generates centrifugal force by swirling the raw material gas passing through it, and this centrifugal force separates and removes solid matter contained in the raw material gas. A multi-cyclone can remove fine solid matter by reducing the diameter of each cyclone. Although the diameter of each cyclone in a multi-cyclone is not particularly limited, it is preferable to select a cyclone diameter that sets a limit particle diameter that can capture the majority of soot particle sizes.

[0030] The dust removal unit 30 may be configured by combining two or more dust removal devices, or by combining a filter-type dust collector such as a ceramic filter with a multi-cyclone. For example, a multi-cyclone and a filter-type dust collector may be arranged upstream. With such a dust removal arrangement, the raw gas passes through the filter-type dust collector after a certain amount of solid matter has been removed by the multi-cyclone. Therefore, the raw gas has a lower solid matter content when passing through the filter-type dust collector, which reduces the frequency of backwashing the filter material of the filter-type dust collector and reduces fluctuations in the raw gas volume due to the introduction of backwash gas. Furthermore, two or more filter-type dust collectors or multi-cyclones may be used, and multiple filter-type dust collectors or multiple multi-cyclones may be arranged in series or parallel to the feed stream.

[0031] In the dust removal section 30, most of the dust contained in the raw material gas is removed. Therefore, the concentration of dust in the raw material gas after passing through the dust removal section 30 is sufficiently lower than the concentration of dust in the raw material gas before passing through the dust removal section 30, and is, for example, 10 mg / Nm ３ Depending on the type of the dust removal unit 30, the dust removal rate may be 5 mg / Nm or less. ３The following is also possible. As described above, the raw material gas also contains tar, and the temperature of the raw material gas when it passes through the dust removal section 30 is relatively high as described above. Therefore, the tar contained in the raw material gas adheres to soot or a powdered adsorbent (such as slaked lime or activated carbon) in the dust removal section 30 and is captured, but gaseous tar is hardly captured and passes through the dust removal section 30 almost as is. Therefore, the tar concentration in the raw material gas after passing through the dust removal section 30 remains approximately the same as the concentration at the outlet of the reformer 13, and the raw material gas is then supplied to the second temperature adjustment section (second temperature reduction section) 40. The adsorbent described above is, for example, injected into the raw material gas at the inlet of the filter-type dust collector, and adheres to the filter material to capture tar and the like as the raw material gas passes through.

[0032] <Second Temperature Adjustment Section> The raw material gas that has passed through the dust removal section 30 is supplied to the second temperature adjustment section 40, where it is preferably adjusted to a temperature of 200°C or less. Preferably, the second temperature adjustment section is a second temperature reduction section that reduces the temperature of the raw material gas that has passed through the dust removal section 30 to 200°C or less. In the following description, the second temperature adjustment section will be described as a temperature reduction section, and the second temperature adjustment section may also be referred to as the second temperature reduction section. By adjusting the temperature to 200°C or less in the second temperature adjustment section (second temperature reduction section) 40, tar that was not removed in the dust removal section 30 is removed in the second temperature reduction section 40 by condensation or the like. Furthermore, adjusting the temperature to 200°C or less makes it easier to adjust the temperature to a temperature suitable for generating organic substances using gas-assimilating bacteria in the organic substance production section 50, as described below. Furthermore, rapidly cooling the temperature to 200°C or less can also suppress dioxin resynthesis.

[0033] In addition, impurities such as tar are removed in the second temperature reducing section 40, but impurities that remain solid even at high temperatures, such as soot and char, are largely removed in the dust remover section 30, so the amount of impurities removed in the second temperature reducing section 40 is small. Therefore, for example, in one example of the second temperature reducing section 40, the amount of impurities mixed into the cleaning liquid of the gas cleaning and cooling tower (described later) is reduced, making it less likely that problems such as blockages in the piping of the cleaning liquid circulation equipment in the gas cleaning and cooling tower will occur, and reducing the frequency of equipment maintenance for the gas cleaning and cooling tower. Furthermore, since large amounts of soot, char, and tar can be prevented from being mixed into the cleaning liquid, there is no need to install a large-scale cleaning liquid treatment facility. Furthermore, since dioxin precursors are largely removed in the dust remover section 30, the risk of dioxin resynthesis in the path from the dust remover section 30 to the second temperature reducing section 40 is also reduced.

[0034] From the viewpoint of facilitating the removal of tar in the second temperature reducing section 40 and facilitating the production of organic substances by gas-assimilating bacteria in the organic substance production section 50, the temperature of the raw material gas is preferably reduced to 150°C or less in the second temperature reducing section 40, and more preferably to 100°C or less. In the case of gas-assimilating bacteria, it is preferable to further reduce the temperature to 50°C or less. In the second temperature reducing section 40, the temperature of the raw material gas is preferably reduced to 10°C or more, more preferably to 20°C or more, and even more preferably to 30°C or more. By reducing the temperature of the raw material gas to the above-mentioned lower limit or above, it becomes easier for the gas-assimilating bacteria to produce organic substances. In addition, it is possible to prevent the temperature from being reduced more than necessary in the second temperature reducing section 40.

[0035] In the raw material gas that passes through the second temperature reducing section 40 and is supplied to the organic substance generation section 50, the tar concentration has no longer reached the dew point at the temperature at the outlet of the second temperature reducing section 40, and the lower the temperature after temperature reduction, the lower the remaining tar concentration.Normally, if the temperature after temperature reduction is 100°C or below, no tar is detected.

[0036] The raw material gas is temperature-adjusted (preferably cooled) in the first temperature adjustment section (first temperature reducing section) 20, and then supplied to the second temperature reducing section 40 with almost no temperature reduction. Therefore, the temperature of the raw material gas supplied to the second temperature reducing section 40 is, for example, 350°C or higher and 550°C or lower, and preferably 400°C or higher and 450°C or lower.

[0037] The second temperature reducing section 40 is preferably one in which the temperature is reduced by direct contact of the gas with a solvent such as water, and is more preferably a gas scrubbing temperature reducing tower. A gas scrubbing temperature reducing tower is a device that brings a cleaning liquid such as water or oil into contact with the raw material gas and removes various impurities while reducing the temperature of the raw material gas using the cleaning liquid. As mentioned above, examples of the impurities to be removed include tar. The cleaning liquid may be water alone or oil alone, or an appropriate chemical may be added. In addition to tar, the second temperature reducing section 40 may also remove water-soluble gas components such as acidic gases such as hydrogen sulfide, hydrogen chloride, and hydrocyanic acid, basic gases such as ammonia, and oxides such as NOx and SOx. Among these, the second temperature reducing section 40 typically removes at least hydrogen chloride and SOx.

[0038] A scrubber is preferably used as the gas washing / desuperheating tower. A scrubber is a device that cools the raw material gas while cleaning it by bringing a washing liquid into contact with the raw material gas passing through the tower. The scrubber may be an oil scrubber in which the washing liquid is oil, but a water scrubber in which the washing liquid is water is preferred. By using a water scrubber, the raw material gas can be easily cooled to a low temperature at low cost.

[0039] The following describes in detail the case where a scrubber is used as a gas cleaning / desuperheating tower. Scrubbers are classified into dry and wet types, but wet scrubbers are particularly preferred. Wet scrubbers are preferred because they can remove water-soluble substances, making impurity removal easier. Furthermore, pooled water scrubbers, Moretana scrubbers, and Neo-Britt scrubbers can efficiently remove impurities, but cause pressure loss in the introduced gas. When impurity removal is important, pooled water scrubbers, Moretana scrubbers, and Neo-Britt scrubbers are preferred. On the other hand, unpacked scrubbers have less pressure loss. When pressure loss is important, it is even more preferable to use an unpacked scrubber. When an unpacked scrubber is used, a process for removing impurities may be further included.

[0040] The wet scrubber is not particularly limited as long as it has a configuration for bringing the raw material gas into contact with a cleaning liquid. For example, as shown in FIG. 2 , the raw material gas passing through the interior of a scrubber 41 from bottom to top is brought into contact with a cleaning liquid sprayed from the top of the scrubber 41, thereby cleaning and cooling the raw material gas. More specifically, a configuration for bringing the cleaning liquid sprayed from a nozzle 42 provided at the top into contact with the raw material gas is preferred. As described above, the cleaning liquid is preferably water. In this case, the scrubber 41 is preferably provided with an inlet passage 43, a supply passage 44, a discharge passage 45, and the like. A reservoir 46 for storing the cleaning liquid is provided at the bottom of the scrubber 41. The cleaning liquid stored in the reservoir 46 may be appropriately stirred by a stirring device (not shown).

[0041] The inlet 43 is a path for introducing the raw gas into the scrubber 41, and an inlet 43A of the inlet 43 is provided, for example, above the liquid level of the cleaning liquid stored in a reservoir 46 inside the scrubber 41. The supply path 44 circulates the cleaning liquid in the scrubber 41 and supplies the cleaning liquid so that it comes into contact with the raw gas. Specifically, the supply path 44 sprays the cleaning liquid stored in the reservoir 46 downward from the nozzle 42 inside the scrubber 41 to bring it into contact with the raw gas. Here, the supply path 44 is provided with, for example, a pump (not shown), and the cleaning liquid is pressure-fed to the nozzle 42 by the pump. The cleaning liquid is then sprayed downward from the nozzle 42 inside the scrubber 41. The discharge path 45 is provided at the top of the scrubber 41 and discharges the raw gas to the outside after coming into contact with the cleaning liquid sprayed from the nozzle 42.

[0042] Furthermore, the scrubber 41 may be provided with a removal device 47. The removal device 47 is a device for removing impurities such as tar contained in the cleaning liquid. For example, the removal device 47 may be provided midway through a circulation path for circulating the water in the reservoir 46. The removal device 47 may remove, for example, oily impurities such as tar contained in the cleaning liquid, solid impurities that do not dissolve in the cleaning liquid, and water-soluble impurities that dissolve in the cleaning liquid. Therefore, the removal device 47 may be an oil-water separator, a filter that removes solids, or a combination of two or more of these. It may have any configuration as long as it can remove impurities contained in the cleaning liquid. By providing the removal device 47, the scrubber 41 prevents impurities from accumulating in the cleaning liquid. Furthermore, moisture in the raw gas supplied to the first temperature reducing section 20 is contained in a saturated state at the raw gas temperature. However, due to the temperature reduction in the first temperature reducing section 20, water equivalent to the dew point falls into the cleaning liquid. Therefore, the increased amount of overflowing water is discharged from the scrubber 41 to the outside of the system, but in the present invention, the treatment of this wastewater is also simplified because the amount of soot and dust is small.

[0043] The temperature of the cleaning liquid that comes into contact with the raw material gas in the scrubber 41 is, in the case of water, less than the saturation temperature of 100° C., and preferably between 0° C. and 40° C. In the case of water, the temperature of the cleaning liquid is kept within the above range by constantly cooling the circulating water, thereby making it possible to cool the raw material gas without evaporating more than necessary.

[0044] The raw material gas is preferably cooled to within the temperature range described above in the scrubber 41. By cooling the raw material gas to a low temperature, it is possible to supply raw material gas at an appropriate temperature to the organic substance generation section 50 without providing a separate cooling device downstream of the scrubber 41, or even if a cooling device is provided, by reducing the load on the cooling device.

[0045] The scrubber 41 is preferably provided with a temperature control device for cooling the circulating cleaning liquid (not shown), and the temperature of the cleaning liquid is preferably controlled by the temperature control device. The temperature control device may be attached to the supply path 44, for example, to adjust the temperature of the cleaning liquid passing through the supply path 44, or may be provided in the reservoir 46 to adjust the temperature of the cleaning liquid stored in the reservoir 46 of the scrubber 41. The temperature control device may cool the cleaning liquid passing through the supply path 44 or the cleaning liquid stored in the reservoir 46 to maintain the temperature within the above-mentioned range. Furthermore, the water stored in the reservoir 46 may be replaced as needed to maintain the temperature of the water that comes into contact with the raw material gas within a certain temperature range.

[0046] In the above description, the scrubber 41 is described as being of a configuration in which the raw gas comes into contact with the cleaning liquid sprayed from the nozzle 42, but other configurations are also possible. For example, the scrubber may be of a type known as a Moretana type, in which multiple shelves are provided inside the scrubber, a layer of cleaning liquid is formed on the shelves, the raw gas is introduced into the layer from the bottom of the scrubber, and the gas rises within the layer, thereby bringing the cleaning liquid into contact with the gas. Even in other configurations, the temperature of the cleaning liquid coming into contact with the raw gas and the temperature of the raw gas (i.e., the temperature of the raw gas introduced into the scrubber 41 and the temperature of the raw gas after cooling) are as described above.

[0047] <Organic Substance Generator> The raw material gas that has passed through the first temperature reducing section 20, the dust removing section 30, and the second temperature reducing section 40 is then supplied to the organic substance generator 50. The raw material gas supplied to the organic substance generator 50 is brought into contact with a microbial catalyst to generate organic substances. The microbial catalyst is a gas-assimilating bacterium. The microorganism may be any microorganism that generates organic substances from the raw material gas through the fermentation action of the gas-assimilating bacterium, and is preferably a microorganism that has a metabolic pathway for acetyl-COA. The gas-assimilating bacterium may be either a eubacterium or an archaebacterium, but the genus Clostridium is preferred.

[0048] When a microbial catalyst is used, the organic substance production unit 50 includes a fermenter (reactor) filled with a culture solution containing water and gas-utilizing bacteria. A raw material gas is supplied into the fermenter, where it is converted into an organic substance. The organic substance is, for example, an alcohol, preferably containing either ethanol or isopropanol, and more preferably containing ethanol. The fermenter is preferably a continuous fermentation apparatus, and may be any of a stirred type, airlift type, bubble column type, loop type, open bond type, and photobio type. The raw material gas and culture solution may be continuously supplied to the fermenter, but the raw material gas and culture solution do not need to be supplied simultaneously. The raw material gas may be supplied to a fermenter to which culture solution has already been supplied. The raw material gas is generally blown into the fermenter via a sparger or the like. Alternatively, the raw material gas may be supplied intermittently to the fermenter.

[0049] The medium used to culture the microbial catalyst is not particularly limited as long as it has an appropriate composition for the bacteria, but is a liquid containing water as the main component and nutrients (e.g., vitamins, phosphoric acid, etc.) dissolved or dispersed in the water. In the organic substance production section 50, organic substances are produced by microbial fermentation of gas-assimilating bacteria, resulting in an organic substance-containing liquid. The temperature of the fermenter is preferably controlled to 40°C or below. By controlling the temperature to 40°C or below, the microbial catalyst in the fermenter is not killed, and organic substances such as ethanol are efficiently produced by contacting the raw material gas with the gas-assimilating bacteria. The temperature of the fermenter is more preferably 38°C or below, and, to enhance catalytic activity, is preferably 10°C or above, more preferably 20°C or above, and even more preferably 30°C or above.

[0050] <Separation device> The organic substance production apparatus preferably includes a separation device 55 that separates organic substances from an organic substance-containing liquid. The separation device 55 preferably includes a distillation device, and more preferably includes a solid-liquid separation device in addition to the distillation device. It is more preferable that the separation device 55 is a combination of a solid-liquid separation device and a distillation device. Below, a specific description will be given of the separation process performed by combining a solid-liquid separation device and a distillation device.

[0051] The organic substance-containing liquid obtained in the organic substance generation unit 50 may be separated in a solid-liquid separation device into a solid component mainly composed of microorganisms and a liquid component containing organic substances. The organic substance-containing liquid obtained in the organic substance generation unit 50 contains, in addition to the target organic substance, microorganisms and their remains contained in the fermenter as solid components, so solid-liquid separation is performed to remove these. Examples of solid-liquid separation devices include filters, centrifuges, and devices using solution precipitation. The solid-liquid separation device may also be a device (e.g., a heat drying device) that evaporates the liquid component containing the organic substance from the organic substance-containing liquid and separates it from the solid component. In this case, the liquid component containing the target organic substance may be entirely evaporated, or the liquid component may be partially evaporated so that the target organic substance is preferentially evaporated.

[0052] The distillation apparatus performs distillation to separate the target organic substance. The distillation apparatus can purify large quantities of organic substances to high purity through simple operations by distillation separation. In a separation process performed in combination with a solid-liquid separator, the distillation apparatus performs distillation to further separate the target organic substance from the liquid component separated by the solid-liquid separator, thereby purifying large quantities of the organic substance to a higher purity. A known distillation column or the like can be used as the distillation apparatus. Furthermore, the distillation can be performed, for example, such that the distillate contains the target organic substance (e.g., ethanol) at a high purity, while the bottoms (i.e., distillation residue) contain water as the main component (e.g., 70% by mass or more, preferably 90% by mass or more). By operating in this manner, the target organic substance and water can be largely separated. The temperature inside the distillation apparatus during the distillation of an organic substance (e.g., ethanol or isopropanol) is not particularly limited, but is preferably 100°C or less, and more preferably 70°C to 95°C. By setting the temperature within the distillation apparatus within the above range, it is possible to reliably separate the necessary organic substances from other components such as water. The pressure within the distillation apparatus during distillation of the organic substances may be normal pressure, but is preferably less than atmospheric pressure, more preferably about 60 kPa or more and 95 kPa or less (absolute pressure). By setting the pressure within the distillation apparatus within the above range, it is possible to improve the separation efficiency of the organic substances and increase the yield of the organic substances.

[0053] The distillation apparatus preferably utilizes thermal energy obtained from the raw material gas in the first temperature reducing section 20 for distillation. The distillation apparatus can increase the temperature inside the distillation apparatus during distillation of the organic substance by reusing the thermal energy obtained from the raw material gas in the first temperature reducing section 20. In this way, by the distillation apparatus reusing the thermal energy obtained from the raw material gas in the first temperature reducing section 20, the amount of energy used in the entire organic substance production process can be reduced. The thermal energy obtained from the raw material gas in the first temperature reducing section 20 can be transferred via a thermal energy path 25 connected to the first temperature reducing section 20 and the distillation apparatus. The thermal energy path 25 is not particularly limited and may have any configuration that transfers the thermal energy of the raw material gas from the first temperature reducing section 20 to the distillation apparatus using a heat medium. Here, as described above, the first temperature reducing section 20 is preferably configured as a boiler, and therefore, steam is preferred as the heat medium. Using steam as the heat medium facilitates the reuse of the thermal energy of the raw material gas.

[0054] The water separated in the separation device 55 may be reused, for example, by supplying it to the gas cleaning and cooling tower of the second temperature reducing section 40 and using it as a cleaning liquid in the gas cleaning and cooling tower. Reusing the water in this manner prevents the water no longer needed in the organic substance production section 50 from being discharged, which is preferable from the standpoints of environmental protection and economy. The organic substance production apparatus 10 may also have a water supply path (not shown) connecting the separation device 55 to the gas cleaning and cooling tower of the second temperature reducing section 40 and supplying the water obtained in the separation device 55 to the gas cleaning and cooling tower. The water supply path is not particularly limited, but may be composed of piping or the like. The water separated in the separation device 55 may also be further purified to increase its purity and then supplied to the gas cleaning and cooling tower.

[0055] As described above, according to this embodiment, the temperature of the raw material gas generated in the gas generation unit 11 is adjusted to a range of 350°C or higher and 550°C or lower in the first temperature adjustment unit 20 before passing through the dust removal unit. This reduces the adhesion of solid soot and char to the interior of the apparatus after the outlet of the dust removal unit 30, thereby reducing the frequency of maintenance of the equipment after the outlet of the dust removal unit 30. This is because the soot and char are mostly removed in the dust removal unit 30, and at the same time, the second temperature adjustment unit 40 prevents the soot and char from being mixed into the cleaning liquid, etc. Therefore, there is no need to provide a large-scale cleaning liquid treatment facility, and the second temperature adjustment unit 40 further removes tar from the raw material gas. Therefore, the configuration of the first temperature adjustment unit 20, the dust removal unit 30, and the second temperature adjustment unit in their respective temperature ranges results in an equipment that is efficient and has excellent maintainability and operability.

[0056] Second Embodiment Next, an organic substance production apparatus and an organic substance production method according to a second embodiment of the present invention will be described. In the second embodiment, an organic substance production apparatus 10A has the same configuration as the organic substance production apparatus according to the first embodiment, except that a gas holder 60 is provided upstream of an organic substance production unit 50. Differences between the second embodiment and the first embodiment will be described below.

[0057] As shown in FIG. 3 , the gas holder 60 may be provided upstream of the organic substance generator 50 and downstream of the second temperature controller 40. The gas holder 60 temporarily stores the raw material gas supplied from the second temperature controller 40. In this embodiment, the raw material gas is supplied to the organic substance generator 50 via the gas holder 60. When generating raw material gas from waste, waste is typically fed in batches to the gas generator 11 (gasifier 12). Also, waste of various types and compositions is typically fed to the gas generator 11. Therefore, the amount of raw material gas produced per unit time and the composition of the raw material gas may vary significantly. However, even in such cases, the gas holder 60 temporarily stores the raw material gas, thereby suppressing fluctuations in the amount (mass flow rate) and composition of the raw material gas supplied per unit time to the organic substance generator 50. This can, for example, keep these values ​​approximately constant. Therefore, the amount of organic material produced per unit time can be increased without inactivating the gas-assimilating bacteria.

[0058] The type of gas holder 60 is not particularly limited as long as it can temporarily store gas, but it is preferable to have a capacity that stabilizes fluctuations in the source gas supply rate or composition at the outlet. This allows for stable organic substance generation in the organic substance generation unit 50. If it is difficult to sufficiently equalize the gas composition using only internal space, an agitator may be installed. The internal pressure of the gas holder is not particularly limited, but as long as it is at a pressure high enough to supply the source gas to the organic substance generation unit 50 (e.g., 500 kPa or higher), there is no need to install a booster blower at the gas holder outlet. Furthermore, the higher the internal pressure, the smaller the required volume of the gas holder can be; however, the internal pressure of the gas holder is preferably approximately the required pressure (500 to 700 kPa) at the inlet of the organic substance generation unit 50 + 100 kPa.

[0059] [Other Embodiments] (Desuperheater) In the first and second embodiments described above, the first temperature reducing section 20 is configured by a boiler. However, the first temperature reducing section 20 may be configured using a device other than a boiler, for example, a water spray type desuperheater, as long as it can reduce the temperature of the raw material gas to 350°C or higher and 550°C or lower. Even when a water spray type desuperheater is used, the temperature in the first temperature reducing section 20 may be reduced to the temperature range described above by the water spray type desuperheater. By reducing the temperature to the temperature range described above, it is possible to prevent condensed tar from adhering to the first temperature reducing section 20 and the dust removal section 30, as described above, and also to reduce the risk of dioxin resynthesis.

[0060] The water spray type desuperheater cools the raw material gas by spraying cooling water at the outlet of the reformer 13. The water spray type desuperheater may have one or more water spray ports. The water spray port may be provided on the inner circumferential surface of the desuperheater that forms the path through which the raw material gas passes, or may be located further inside than the inner circumferential surface, for example, at the center of the path.

[0061] The raw material gas supplied to the temperature reducing section 20 (i.e., the water spray type attemperator) is at a high temperature as described above, while the cooling water sprayed from the water spray orifice is at or below 100°C. The raw material gas is cooled by this temperature difference and also by the heat of vaporization when the water sprayed from the water spray orifice vaporizes. Note that the water sprayed from the water spray orifice may be partially or completely vaporized when sprayed. The water that is mixed into the raw material gas as vapor in the water spray type attemperator becomes water when its temperature drops to 100°C or below in the second attemperator and is recovered.

[0062] In addition, a boiler and a water spray type desuperheater may be used in combination in the first desuperheater section 20, and a desuperheater device other than a boiler or a water spray type desuperheater may be provided in the first desuperheater section 20. For example, a heat exchanger other than a boiler or a water spray type desuperheater may be used, and the temperature of the raw material gas may be reduced by the heat exchanger. When a heat exchanger other than a boiler or a water spray type desuperheater is used, the heat exchanger may be used in combination with both the boiler and the water spray type desuperheater in the first desuperheater section 20, or may be used alone.

[0063] (Metal Catalyst) In each of the above embodiments, the organic substance production unit uses gas-assimilating bacteria to convert the raw material gas into organic substances through the action of the gas-assimilating bacteria, but the organic substances may also be produced using a catalyst other than gas-assimilating bacteria. Examples of catalysts other than gas-assimilating bacteria include metal catalysts.

[0064] Examples of the metal catalyst include hydrogenation active metals, or a combination of a hydrogenation active metal and a co-active metal. Examples of the hydrogenation active metal include metals known to be capable of synthesizing ethanol from a feed gas, such as alkali metals (lithium, sodium, etc.), elements belonging to Group 7 of the periodic table (manganese, rhenium, etc.), elements belonging to Group 8 of the periodic table (ruthenium, etc.), elements belonging to Group 9 of the periodic table (cobalt, rhodium, etc.), and elements belonging to Group 10 of the periodic table (nickel, palladium, etc.). These hydrogenation active metals may be used alone or in combination of two or more. From the viewpoint of further improving the CO conversion rate and improving the ethanol selectivity, preferred hydrogenation active metals are combinations of rhodium, manganese, and lithium, or combinations of ruthenium, rhenium, and sodium, or combinations of rhodium or ruthenium with an alkali metal and another hydrogenation active metal.

[0065] Examples of the promoter active metal include titanium, magnesium, and vanadium. Supporting a promoter active metal in addition to a hydrogenation active metal can further increase the CO conversion rate, ethanol selectivity, and the like. A rhodium-based catalyst is preferred as the metal catalyst. The rhodium-based catalyst may be used in combination with a metal catalyst other than the rhodium-based catalyst. Examples of the other metal catalyst include a catalyst in which copper alone or copper and a transition metal other than copper are supported on a carrier. Even when a metal catalyst is used, the organic substance production section may include a reactor, and the organic substance may be produced by contacting the raw material gas with the metal catalyst inside the reactor. The temperature inside the reactor may be maintained, for example, at 100°C or higher and 400°C or lower, preferably at 100°C or higher and 300°C or lower.

[0066] When a metal catalyst is used, the organic substance production apparatus may include a heater disposed downstream of the second temperature adjustment section (second temperature reducing section) 40 and upstream of the organic substance production section 50, and the raw material gas whose temperature has been reduced in the second temperature reducing section may be heated by the heater and then supplied to the organic substance production section. As the heater, a heat exchanger or a known heater may be used. The raw material gas may be heated in the heater to a temperature optimal for the reaction.

[0067] Although the above description has been given of an embodiment in which the raw material gas is obtained from waste in the gas generator 11, as long as the raw material gas contains carbon monoxide, carbon dioxide, and hydrogen, the raw material gas may be generated from sources other than waste in the gas generator 11. For example, the raw material gas may be generated from fossil resources such as natural gas, coal, heavy oil, petroleum exhaust gas, and oil shale, or from biomass other than waste.

[0068] Between the gas generation unit 11 and the organic substance generation unit 50, one or more devices may be provided, such as a moisture separation device consisting of a gas chiller or the like, a low-temperature separation (cryogenic) separation device, a particulate separation device consisting of various filters, a desulfurization device (sulfide separation device), a membrane separation device, a deoxygenation device, a pressure swing adsorption (PSA) separation device, a temperature swing adsorption (TSA) separation device, a pressure temperature swing adsorption (PTSA) separation device, a separation device using activated carbon, a separation device using a deoxygenation catalyst, specifically a copper catalyst or a palladium catalyst, a shift reaction device, etc.

[0069] REFERENCE SIGNS LIST 10, 10A Organic substance production apparatus 11 Gas generation section 12 Gasification furnace 13 Reformer furnace 20 First temperature reducing section (first temperature adjustment section) 25 Thermal energy path 30 Dust removal section 40 Second temperature reducing section (second temperature adjustment section) 41 Scrubber 50 Organic substance production section 60 Gas holder

Claims

1. An organic substance manufacturing apparatus comprising: a gas generation unit which generates a raw material gas containing carbon monoxide, carbon dioxide and hydrogen; an organic substance generation unit which is supplied with the raw material gas and which generates an organic substance from the raw material gas; a first temperature adjustment unit which adjusts the temperature of the raw material gas discharged from the gas generation unit to within the range of 350°C or higher and 550°C or lower; a dust removal unit which includes a dust collector; and a second temperature adjustment unit which adjusts the temperature of the raw material gas to 200°C or lower, wherein the first temperature adjustment unit, the dust removal unit and the second temperature adjustment unit are arranged in this order from upstream between the gas generation unit and the organic substance generation unit.

2. The organic substance manufacturing apparatus according to claim 1, further comprising a gas holder upstream of said organic substance production section.

3. An organic substance manufacturing apparatus according to claim 1 or 2, wherein the dust collector includes at least one of a filter-type dust collector and a multi-cyclone.

4. An organic substance manufacturing apparatus as described in claim 1 or 2, wherein the first temperature adjustment section includes at least one of a boiler and a water spray type desuperheater.

5. An organic substance manufacturing apparatus as described in claim 1 or 2, wherein the second temperature control section includes a scrubber.

6. The organic substance manufacturing apparatus according to claim 1 or 2, wherein the gas generating section generates the raw material gas from waste.

7. An organic substance manufacturing apparatus as described in claim 1 or 2, wherein the organic substance production section produces organic substances by the action of gas-utilizing bacteria.

8. A method for producing an organic substance, comprising: generating a raw material gas containing carbon monoxide, carbon dioxide and hydrogen; treating the generated raw material gas in the order of a step of adjusting the temperature of the raw material gas to within a range of 350°C to 550°C; a step of passing the raw material gas through a dust removal section; and a step of adjusting the temperature of the raw material gas to 200°C or less; and producing an organic substance from the treated raw material gas.