JP6161364B2 - Method for producing fuel gas - Google Patents

Description

  The present invention relates to a method for producing fuel gas.

  Conventionally, domestic wastewater, wastewater from food processing plants, wastewater from livestock houses, poultry farms, etc., wastewater such as industrial wastewater containing components that are difficult to biologically treat, wastewater containing alcohols, carboxylic acids, aldehydes, etc. Are processed by an individual technique according to each characteristic.

  In recent years, it has been studied to reuse the wastewater as a resource. Patent Document 1 discloses a method for producing a fuel gas mainly composed of hydrogen, including a step of hydrothermal reaction of a liquid organic substance in subcritical water or supercritical water using a catalyst and sulfur or a sulfur compound. Has been. In Patent Document 2, a liquid organic substance is hydrothermally reacted in subcritical water or supercritical water using a catalyst to obtain a fuel gas containing hydrogen, and then impurities are removed from the fuel gas. A method is disclosed.

  In addition, the wastewater may contain an organic sulfur compound such as dimethyl sulfoxide (DMSO). Therefore, it is also important to reuse wastewater containing organic compounds containing sulfur atoms (organic sulfur compounds) such as DMSO as resources. Thus, it has been studied to produce a fuel gas by causing a hydrothermal reaction of waste water containing an organic sulfur compound using a catalyst. However, organic sulfur compounds are known as substances (catalyst poisons) that react with the catalyst to significantly reduce the function of the catalyst, and there is room for study to produce fuel gas from wastewater containing organic sulfur compounds. was there.

  Therefore, it is desired to produce fuel gas satisfactorily from wastewater containing organic sulfur compounds without causing catalyst poisoning.

JP 2005-225898 A JP 2005-281343 A

  An object of this invention is to provide the method of manufacturing fuel gas favorably from the wastewater containing an organic sulfur compound, without causing catalyst poisoning.

  The present inventor has studied the above problems. And this inventor discovered that fuel gas can be manufactured favorably from wastewater containing an organic sulfur compound, without causing catalyst poisoning, by including lower alcohols, such as methanol, in wastewater containing an organic sulfur compound. .

  The present invention provides the following fuel gas production method.

  Item 1. A fuel gas production method for producing a fuel gas by hydrothermally reacting waste water containing an organic sulfur compound and a lower alcohol in the presence of a catalyst.

  Item 2. Item 2. The method for producing fuel gas according to Item 1, wherein the waste water contains 1/10 (lower alcohol / sulfur mass ratio) or more of lower alcohol with respect to sulfur contained in the organic sulfur compound.

  Item 3. Waste water containing the lower alcohol and organic sulfur compound is obtained by adding lower alcohol to waste water containing organic sulfur compound, or obtained by mixing waste water containing organic sulfur compound and waste water containing lower alcohol The method for producing fuel gas according to Item 1 or 2, wherein

  Item 4. The catalyst is a catalyst in which a catalytically active component is supported on a carrier, and the carrier is at least one carrier selected from the group consisting of activated carbon, titania, zirconia, titania-zirconia, alumina, silica, and alumina-silica. And the catalytically active component is selected from the group consisting of Ni, Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Co, Mn and Ce and their water-insoluble or poorly water-soluble compounds. Item 4. The method for producing fuel gas according to any one of Items 1 to 3, which is at least one active ingredient.

  Item 5. Item 5. The method for producing fuel gas according to Item 4, wherein the catalyst composition has a supported amount of the catalytically active component on the carrier of 0.01 to 60% by weight.

Item 6. Item 6. The fuel gas production method according to any one of Items 1 to 5, wherein the hydrothermal reaction is a reaction performed at a temperature of 200 to 350 ° C, a pressure of 5 to 12 MPa, and a liquid space velocity of 0.1 to 10 h- ^1. .

  Item 7. Item 7. The method for producing fuel gas according to any one of Items 1 to 6, wherein the lower alcohol is methanol.

  The fuel gas production method of the present invention can produce fuel gas satisfactorily from wastewater containing an organic sulfur compound without causing catalyst poisoning.

It is a figure which shows one Embodiment of the manufacturing method of the fuel gas of this invention. It is a figure which shows the test apparatus for laboratories which is one Example of the manufacturing method of the fuel gas of this invention.

  Each process of the manufacturing method of the fuel gas of this invention, the component to be used, etc. are demonstrated in detail.

  The fuel gas production method of the present invention is characterized in that fuel gas is produced by hydrothermal reaction of wastewater containing an organic sulfur compound and a lower alcohol such as methanol in the presence of a catalyst.

  In the fuel gas production method of the present invention, when a wastewater containing an organic sulfur compound is hydrothermally treated in the presence of a catalyst, the wastewater contains a lower alcohol such as methanol, so that catalyst poisoning by the organic sulfur compound occurs. In addition, fuel gas can be produced satisfactorily from wastewater containing organic sulfur compounds.

1. Wastewater subjected to hydrothermal reaction The wastewater subjected to heat treatment contains an organic sulfur compound and a lower alcohol such as methanol.

  The wastewater is not particularly limited as long as it is a wastewater containing an organic sulfur compound and a lower alcohol such as methanol. For example, it means a liquid mixture in which a lower alcohol such as methanol and a liquid and / or solid organic sulfur compound are dissolved or dispersed in water. The organic sulfur compound may be dissolved in a gaseous state. For example, wastewater containing various organic materials (alcohols, ethers, carboxylic acids, aldehydes, etc.) provided as industrial raw materials and fuels, domestic wastewater (human waste, etc.), industrial wastewater (semiconductor manufacturing factory wastewater, food factory wastewater, Paper mill wastewater, pharmaceutical factory wastewater, photographic wastewater, printing wastewater, agricultural chemical-related wastewater, dyeing wastewater, plating wastewater, wastewater generated by coal liquefaction or gasification, wastewater generated by pyrolysis of municipal waste, etc.), sludge Wastewater containing liquid or water-containing organic waste such as sewage, waste wood, waste wood, paper, wastewater containing a mixture of organic waste liquid such as paper, plastics, etc., or biological, physical, chemical Wastewater that has been treated automatically. These waste waters can be treated by mixing two or more kinds.

  Waste water that originally contains an organic sulfur compound and a lower alcohol such as methanol can be used. Moreover, it can be set as the waste water containing an organic sulfur compound and lower alcohols, such as methanol, by adding lower alcohols, such as methanol, to the waste water containing an organic sulfur compound. Moreover, the wastewater containing organic sulfur compounds and the wastewater containing lower alcohols, such as methanol, can be mixed, and it can be set as the wastewater containing an organic sulfur compound and lower alcohols, such as methanol.

  FIG. 1 is a diagram showing an embodiment of a method for producing fuel gas of the present invention. In a wastewater tank, organic sulfur compounds and methanol are added by adding lower alcohol such as methanol to wastewater containing organic sulfur compounds, or mixing wastewater containing organic sulfur compounds and wastewater containing lower alcohols such as methanol. It can be set as the wastewater containing lower alcohols, such as.

Lower alcohol In the fuel gas production method of the present invention, lower alcohol is contained in the wastewater.

  The lower alcohol is preferably a lower alcohol having 5 or less carbon atoms. The waste water preferably contains at least one lower alcohol having 5 or less carbon atoms. Examples of the lower alcohol include methanol, ethanol, propanol, isopropyl alcohol, butanol (1-butanol (n-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), 2-butanol (sec-butyl alcohol), 2 -Methyl-2-propanol (tert-butyl alcohol), etc.), pentanol (1-pentanol, 3-methyl-1-butanol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol, 2 -Pentanol, 3-methyl-2-butanol, 3-pentanol, 2-methyl-2-butanol, etc.).

  Lower alcohol can suppress catalyst poisoning by organic sulfur compounds. In the method for producing fuel gas of the present invention, since the lower alcohol is contained in the waste water containing the organic sulfur compound, catalyst poisoning by the organic sulfur compound does not occur, and the fuel gas can be produced satisfactorily from the waste water containing the organic sulfur compound. . The wastewater preferably contains an appropriate amount of a lower alcohol.

  The lower alcohol concentration in the wastewater is preferably adjusted so that the lower alcohol is contained in an amount of 1/10 (mass ratio of lower alcohol / sulfur) or more with respect to sulfur contained in the organic sulfur compound in the wastewater.

As the methanol lower alcohol, it is particularly preferable to use methanol. There is no particular limitation on the form of methanol contained in the wastewater. When adding methanol to waste water containing an organic sulfur compound, industrial methanol can be used. In addition, methanol is used as a raw material for synthesizing various organic compounds or used as a solvent for various chemical reactions. Methanol remaining after its use can be used. In addition, separately prepared wastewater containing methanol can be mixed with wastewater containing organic sulfur compounds.

Organic sulfur compound An organic sulfur compound is an organic compound containing a sulfur atom. The organic sulfur compound is not particularly limited. Examples of the organic sulfur compound include a thiol compound having a mercapto group (—SH) and represented by R—SH; a sulfide compound having a thioether bond (—S—) and represented by the general formula RS—R ′; A disulfide compound having a —SS— bond in it; a halogenated sulfenyl compound represented by the general formula R-SX (X is halogen); a molecule having —SO— in the molecule and represented by the general formula R-SO-R ′. A sulfoxide compound (dimethylsulfoxide, etc.); a sulfone compound having —SO ₂ — in the molecule and represented by the general formula R—SO ₂ —R ′ (dimethylsulfone, etc.); A thioaldehyde compound represented by the general formula R-CHS; a thiocarboxylic acid compound of thiolic acid (R-COSH), thionic acid (R-CSOH) and dithioic acid (R-CSSH); monothiocarbonate ( HO-CO-SH), thione carbonate (HO-CS-OH), dithiocarbonate (HS-CO-SH), thiol-thio Thiocarbonic acid compounds of thiocarbonic acid (HO-CS-SH) and trithiocarbonic acid (HS-CS-SH); Thiocarbamic acid compounds represented by the general formula H ₂ N-COSH or H ₂ N-CSOH; SO ₃ H) and a sulfonic acid compound represented by the general formula R—SO ₃ H (methanesulfonic acid, its salt, etc.); a sulfinic acid compound represented by the general formula R—SO ₂ H; Examples thereof include sulfenic acid compounds represented by SOH; thiosulfonic acid compounds represented by the general formula R—SO ₂ SH; sulfamic acids which are N-alkyl and N-aryl derivatives of sulfamic acid H ₂ N—SO ₃ H, and the like.

Examples include dimethyl sulfoxide (DMSO, CH ₃ —SO—CH ₃ ), dimethyl sulfone (MSM, CH ₃ —SO ₂ —CH ₃ ), methanesulfonic acid (CH ₃ —SO ₃ H), sodium methanesulfonate, etc. Waste water can be used.

  The organic sulfur compound concentration in the wastewater is preferably adjusted so that the lower alcohol is contained in an amount of 1/10 (mass ratio of lower alcohol / sulfur) or more with respect to the sulfur contained in the organic sulfur compound in the wastewater. .

The abundance ratio of lower alcohol and sulfur is included in lower alcohol and organic sulfur compounds, considering that catalyst poisoning by organic sulfur compounds does not occur and fuel gas can be produced satisfactorily from wastewater containing organic sulfur compounds. It is preferable to adjust the mass ratio (lower alcohol: sulfur) with sulfur. That is, in the fuel gas production method of the present invention, the concentration of the lower alcohol or organic sulfur compound (or sulfur) in the wastewater is not necessarily important, and the mass ratio between the lower alcohol and sulfur contained in the organic sulfur compound is important. is there.

  The abundance ratio (mass ratio) between lower alcohol and sulfur in wastewater is 1/10 (lower alcohol / lower relative to sulfur contained in the organic sulfur compound). Sulfur mass ratio) is preferably included. That is, it is preferable that 10 mass% or more of lower alcohol is contained with respect to the sulfur contained in an organic sulfur compound in wastewater. The higher the ratio of the lower alcohol to sulfur contained in the organic sulfur compound, the better, and the upper limit is not particularly limited.

  In the waste water, the lower alcohol is more preferably contained in an amount of about 1/10 to 20/1 (mass ratio of lower alcohol / sulfur) with respect to sulfur contained in the organic sulfur compound. That is, the lower alcohol: sulfur (mass ratio) in the wastewater is more preferably about 1:10 to 20: 1. The mass ratio of lower alcohol / sulfur is more preferably about 5/1 to 10/1, and more preferably about 8/1 to 10/1. That is, the lower alcohol: sulfur (mass ratio) is more preferably about 5: 1 to 10: 1, and more preferably about 8: 1 to 10: 1.

  By adjusting the mass ratio of the lower alcohol and the sulfur or organic sulfur compound in the wastewater, the hydrothermal reaction by the catalyst proceeds well.

A fuel gas can be produced from an organic compound in the presence of a catalyst poisoning catalyst. However, if the organic compound is an organic compound containing a sulfur atom (organic sulfur compound), the catalyst is poisoned by the sulfur and the catalytic activity is reduced. That is, the catalyst is covered with sulfur, and sulfur poisoning of the catalyst occurs. Therefore, in the conventional fuel gas production method, it is difficult to produce fuel gas from an organic sulfur compound efficiently and continuously even in the presence of a catalyst, and there is room for investigation.

  In the method for producing fuel gas of the present invention, since the lower water such as methanol is contained in the waste water, the catalyst used for the hydrothermal reaction is not poisoned by the organic sulfur compound. The mechanism by which the catalyst is not poisoned by the lower alcohol such as methanol is considered to be because the lower alcohol and the organic sulfur compound react with each other and the catalyst is prevented from being covered with sulfur. As a result, fuel gas can be produced satisfactorily from wastewater containing organic sulfur compounds. In addition, wastewater containing lower alcohols such as methanol can be effectively used.

Other conditions of wastewater The pH of wastewater is not particularly limited. The pH is preferably about 5 to 12 and more preferably about 6 to 10 because the hydrothermal reaction in the presence of the catalyst proceeds favorably.

  The total organic carbon (hereinafter also referred to as “TOC”) in the wastewater is not particularly limited. From the advantage that fuel gas can be produced satisfactorily from wastewater containing an organic sulfur compound, the TOC of the whole organic matter in the wastewater (meaning that it contains not only lower alcohol but also all other organic matter) is 1 to 100 g / L. The degree is preferable, about 10 to 80 g / L is more preferable, and about 20 to 50 g / L is further preferable.

  The suspended solid concentration in the wastewater (hereinafter also referred to as “SS concentration”) is not particularly limited. The SS concentration is preferably about 1 g / L or less, more preferably about 0.1 g / L or less, from the viewpoint of preventing clogging or contamination of the reactor, heat exchanger, piping, filters, valves and the like. The treatment method of the present invention is particularly effective for wastewater having an SS concentration of about 0.01 g / L or less.

  The waste water may contain an inorganic substance. As an inorganic substance, metals, such as Mg, Al, Si, P, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and these metal compounds are mentioned, for example. The density | concentration of the inorganic substance in the wastewater containing an organic sulfur compound is not specifically limited. The concentration of the inorganic substance is preferably about 50 mg / l or less from the viewpoint that the catalyst functions effectively.

2. Hydrothermal reaction of waste water The method for producing fuel gas of the present invention produces fuel gas by hydrothermal reaction of waste water containing an organic sulfur compound and a lower alcohol such as methanol in the presence of a catalyst.

  In one embodiment of the fuel gas production method shown in FIG. 1, wastewater is treated. Waste water in the waste water tank is supplied to a reactor filled with a catalyst through a pump, a preheater, and a heater. In the reactor, the wastewater is hydrothermally reacted using a catalyst to produce fuel gas. The treated water after the hydrothermal reaction contains fuel gas. The treated water after the hydrothermal reaction is cooled in a preheater and a cooler. The treated water after the hydrothermal reaction is sent to a gas-liquid separator through a pressure reducing valve (not shown) and separated into a gas phase (fuel gas) and a liquid phase (exhaust water). In this embodiment, the pressure reducing valve is provided in front of the gas-liquid separator. However, the position of the pressure reducing valve is not particularly limited, and may be provided after the gas-liquid separator.

The catalyst catalyst is preferably a catalyst in which a catalytically active component is supported on a carrier.

  The catalyst is preferably a catalyst supporting at least one metal selected from the group consisting of transition metals including noble metals and base metals with a carbonaceous support or metal oxide support as a support.

  The carrier is preferably at least one carrier selected from the group consisting of activated carbon, titania, zirconia, titania-zirconia, alumina, silica and alumina-silica. Among these, in particular, at least one carrier selected from titania and activated carbon is preferable, and activated carbon is more preferable. There is an advantage that the specific surface area is large.

  As the catalytically active component, any particulate catalyst having a metal as an active component can be adopted. The catalytically active component is at least one selected from the group consisting of Ni, Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Co, Mn, and Ce and water-insoluble or poorly water-soluble compounds thereof. It is preferable that it is an active ingredient. Among these, at least one active ingredient selected from Ru and Ni is particularly preferable, and Ni is more preferable.

  In the composition of the catalyst, the amount of the catalytically active component supported on the carrier is preferably about 0.01 to 60% by weight, more preferably about 0.1 to 60% by weight.

  The shape of the catalyst is not particularly limited, and examples thereof include a spherical shape, a pellet shape, a columnar shape, a crushed piece shape, a powder shape, and a honeycomb shape. From the viewpoint of reaction efficiency, it is preferably spherical. When the catalyst is spherical, the catalyst particle size is preferably about 0.1 to 10 mm, more preferably about 0.1 to 8 mm. There is an advantage that the contact area becomes large.

  As a method of supporting a metal which is a catalytically active component on a support, a known method is adopted, and for example, impregnation, alkali treatment, reduction and the like can be performed in combination.

  For example, the catalyst described in Japanese Patent No. 4010369 or Japanese Patent No. 3629523 can be used.

  The catalyst preferably has pores having a pore size of 0.5 to 20 nm, and more preferably has a pore size of 1 to 10 nm. The pore diameter of the catalyst can be measured using a nitrogen adsorption method and a mercury intrusion method.

The catalyst preferably has a BET specific surface area of 100 to 300 m ² / g, more preferably 150 to ²⁰⁰ m ² / g. Gasification efficiency is improved. The BET specific surface area can be measured by a nitrogen adsorption method.

  The catalyst of the present invention can be prepared, for example, by the following method. First, an aqueous solution of a nickel compound is allowed to act on an ion exchange resin to be bound and supported by ion exchange. Next, the nickel-supported catalyst can be obtained by firing and carbonizing the ion-exchange resin (nickel-supported polymer organic material) supporting the nickel at 450 ° C. to 550 ° C.

  As the ion exchange resin, either a strong acid ion exchange resin or a weak acid ion exchange resin can be used. As the nickel compound, a water-soluble one can be used. The nickel compound is preferably contained in an amount of about 40 to 60% of nickel with respect to the carbonized product after the carbonization of the polymer organic material.

  Since a catalyst is used in the present invention, the hydrothermal reaction is promoted and the decomposition rate of the organic sulfur compound in the wastewater is improved. In the present invention, since the waste water contains lower alcohol such as methanol, the catalyst is not poisoned by the organic sulfur compound. As a result, fuel gas can be produced satisfactorily from wastewater containing organic sulfur compounds.

Hydrothermal reaction conditions The temperature of the hydrothermal reaction is preferably about 200 to 350 ° C, more preferably about 250 to 300 ° C, from the advantage that the hydrothermal reaction proceeds well.

  The pressure (gauge pressure) of the hydrothermal reaction is preferably about 5 to 12 MPa, more preferably about 6 to 11 MPa, from the advantage that the hydrothermal reaction proceeds well.

Liquid hourly space velocity of the hydrothermal reaction (LHSV, entrance criteria) from advantage hydrothermal reaction proceeds satisfactorily, and preferably 0.1~10h about ^-1, more preferably 0.5～8H ^-1 Degree. The liquid hourly space velocity (LHSV) is the ratio of the raw material liquid supply rate (20 ° C liquid volume flow rate) to the reactor volume or catalyst filling volume to the continuous reactor, and indicates the raw material liquid supply rate per unit time. Is h- ¹ .

3. Fuel gas The fuel gas is preferably a gas containing at least one selected from the group consisting of methane, ethane and propane. Depending on the hydrothermal reaction conditions, the fuel gas is usually 40 to 90% by volume of methane, 0 to 15% by volume of ethane, 0 to 15% by volume of propane, and 0 to 25% by volume of hydrogen. About 10 to 60% by volume of carbon dioxide is contained.

  In general, a sulfur component contained in wastewater poisons the catalyst and reduces the catalytic activity. In the fuel gas production method of the present invention, the waste water containing the organic sulfur compound to be treated further contains a lower alcohol such as methanol, so that the catalyst used for the hydrothermal reaction is not poisoned. In the fuel gas production method of the present invention, catalyst poisoning does not occur, and fuel gas can be produced satisfactorily from wastewater containing organic sulfur compounds. Such an effect produced by the fuel gas production method of the present invention is surprising. According to the fuel gas production method of the present invention, a long-term continuous treatment is possible while maintaining a high organic matter decomposition rate of the catalyst.

4). Application of fuel gas production method According to the fuel gas production method involving a hydrothermal reaction of the present invention, a fuel gas can be produced from an organic sulfur compound.

  The energy generated in the process of producing the fuel gas can be recovered in the form of heat, electric power or the like by a known method at any stage of the gas-liquid mixed phase, gas phase, and liquid phase.

  The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

<Examples and Comparative Examples>
1. Method for producing fuel gas
(1) FIG. 2 shows a test apparatus flow for a reactor laboratory.

(2) Raw water used for the reaction (waste water tank)
The following aqueous solutions were prepared and used as raw water.

Raw water A: sodium methanesulfonate 147,500 mg / L (organic sulfur compound)
Raw water B: sodium methanesulfonate 14,750mg / L
Raw water C: sodium methanesulfonate 14,750mg / L
+ Methanol 36,000mg / L (lower alcohol)
In the raw water C, methanol (lower alcohol) is contained in 9/1 (lower alcohol / sulfur mass ratio) with respect to sulfur contained in sodium methanesulfonate (organic sulfur compound).

(3) Hydrothermal reaction conditions (reaction tube)
Set temperature: 270 ° C
Setting pressure: 8.8 MPaG (gauge pressure)
Setting liquid amount: 130 g / h
Catalyst: The catalyst described in Japanese Patent No. 3629523 was used. This is a catalyst in which Ni is supported as a substance having a catalytic function on a carbon support. The amount of the substance having a catalytic function in the catalyst is 40 to 55% by weight. The catalyst is spherical, has a particle size of 0.1 to 1 mm, and has pores with a pore size of 0.5 to 20 nm. The BET specific surface area is 150 to ²⁰⁰ m ² / g.

Catalyst amount: 13 mL
According to the flow shown in FIG. 2, the raw water A to C was used as wastewater containing an artificially prepared organic sulfur compound, and fuel gas was produced. First, raw water in a wastewater tank was supplied to a reaction tube filled with a catalyst via a pump. The conditions of the reaction tube are as described above. Next, the raw water was subjected to a hydrothermal reaction using a catalyst in a reaction tube to produce a fuel gas. In order to obtain a temperature suitable for the reaction, heating was appropriately performed. Next, the treated water after the hydrothermal reaction was cooled in a cooler. Next, the treated water after the hydrothermal reaction was sent to a gas-liquid separator through a pressure holding valve, and separated into a gas phase (generated gas) and a liquid phase (treated water).

  The obtained treated water was sampled, and the total organic carbon decomposition rate (TOC decomposition rate) was determined by measuring the TOC concentration in the treated water. The obtained gas was sampled and the concentration of each component in the product gas was measured. The product gas after the hydrothermal reaction using the raw water C contained fuel gas.

2. Results Table 1 shows the TOC decomposition rate of raw water and the composition of fuel gas.

  As shown in Comparative Examples 1 and 2, when raw waters A and B containing no lower alcohol such as methanol were used, the catalytic activity decreased rapidly after the start of operation, and after 6 hours, the TOC decomposition rate was 2.1. %Met. Moreover, the catalytic activity was quickly reduced, and it was not possible to produce fuel gas from raw water containing an organic sulfur compound.

  On the other hand, as shown in Example 1, when raw water C containing methanol as the lower alcohol was used, the catalytic activity was maintained, and the TOC decomposition rate was maintained at 89.6% even after 24 hours. Moreover, fuel gas was able to be manufactured satisfactorily from raw water containing an organic sulfur compound.

  The fuel gas production method of the present invention can produce a fuel gas by hydrothermally reacting waste water containing an organic sulfur compound and a lower alcohol in the presence of a catalyst. Hydrothermal reaction does not cause catalyst poisoning with organic sulfur compounds, and can produce fuel gas from waste water containing organic sulfur compounds.

Claims (7)

A fuel gas production method for producing a fuel gas by hydrothermally reacting wastewater containing an organic sulfur compound and a lower alcohol in the presence of a catalyst , wherein the organic sulfur compound is not contaminated. A method for producing fuel gas, comprising adding the lower alcohol according to an amount . In the waste water, a lower alcohol, with respect to sulfur contained in organic sulfur compounds, is added so as to be contained 1/10 (lower alcohol / mass ratio of sulfur) above, in the method of manufacturing a fuel gas according to claim 1 .   Waste water containing the lower alcohol and organic sulfur compound is obtained by adding lower alcohol to waste water containing organic sulfur compound, or obtained by mixing waste water containing organic sulfur compound and waste water containing lower alcohol The method for producing fuel gas according to claim 1 or 2, wherein   The catalyst is a catalyst in which a catalytically active component is supported on a carrier, and the carrier is at least one carrier selected from the group consisting of activated carbon, titania, zirconia, titania-zirconia, alumina, silica, and alumina-silica. And the catalytically active component is selected from the group consisting of Ni, Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Co, Mn and Ce and their water-insoluble or poorly water-soluble compounds. The method for producing fuel gas according to any one of claims 1 to 3, which is at least one active ingredient.   The method for producing fuel gas according to claim 4, wherein the catalyst composition is such that the amount of the catalytically active component supported on the carrier is 0.01 to 60% by weight. The method for producing fuel gas according to claim 1, wherein the hydrothermal reaction is a reaction performed at a temperature of 200 to 350 ° C., a pressure of 5 to 12 MPa, and a liquid space velocity of 0.1 to 10 h ^−1. .   The method for producing fuel gas according to claim 1, wherein the lower alcohol is methanol.

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