JP2015017197A - Method for gasifying organic waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which gasifies organic waste, generated in small amount or intermittently, at a low cost and with high efficiency by maintaining the activity of a catalyst for a long time.SOLUTION: Organic waste is gasified by a method which includes the steps of: pressurizing and heating an object to be treated containing organic waste and water to start a hydrothermal reaction at a pressure of 1.5-50 MPa and at a temperature of 200-500°C; bringing the pressurized and heated object to be treated into contact with a porous granular catalyst containing a metal and having a bulk density of 1-8 g/cmat a pressure of 1.5-50 MPa and at a temperature of 200-500°C to decompose the organic waste; and pressure-reducing or cooling the object to be treated containing the decomposed products to perform gas-liquid separation.

Description

  The present invention relates to a method for gasifying organic waste. More specifically, the present invention relates to a method for gasifying organic waste that may be generated in a small amount or intermittently at low cost and with high efficiency while maintaining the activity of the catalyst for a long time.

  Incineration as a method to dispose of organic waste such as waste plastics, waste rubber, shredder dust, livestock manure, garbage, beer lees, sake lees, soy sauce lees, shochu, blood mixed waste, sewage sludge, antigen antibody culture waste Treatment and biological treatment are known. In the incineration process, it is necessary to perform a dehydration process or solid content aggregation before the incineration. Dioxins may be generated due to incomplete combustion. Biological treatment takes a long time for treatment, and activated sludge generated after treatment becomes new waste.

  There are known methods for decomposing organic waste in hot water such as subcritical water, superheated steam, and supercritical water. For example, Patent Documents 1 and 2 are in contact with subcritical water or supercritical water in the presence of a metal catalyst comprising a hydrogen-activated metal and an oxidizing agent or an alkaline catalyst at a reaction pressure of 5 to 50 MPa and a reaction temperature of 200 to 800 ° C. A method for gasifying an organic substance is disclosed.

JP 2003-201486 A JP 2009-30071 A

In the methods described in Patent Documents 1 and 2, the catalyst activity decreases in a short time, and long-term operation is difficult, and the cost may increase due to recharging of the catalyst.
An object of the present invention is to provide a method for gasifying organic waste, which may be generated in a small amount or intermittently, at low cost and high efficiency while maintaining the activity of the catalyst for a long time.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have completed the present invention including the following forms.

[1] Pressurizing and heating an object to be treated containing organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C.
The pressed and heated workpiece is brought into contact with a porous granular metal-containing catalyst having a bulk density of 1 to 8 g / cm ³ at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification method comprising: a step of decomposing waste; and a step of gas-liquid separation by depressurizing or cooling an object to be treated containing the decomposition product.

[2] A step of pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C.
A step of reducing the molecular weight of the organic waste by bringing the pressurized and heated workpiece into contact with activated carbon at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
An object to be treated containing organic waste reduced in molecular weight has a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification method comprising: a step of decomposing organic waste by contacting, and a step of depressurizing or cooling an object to be treated containing the decomposition product to perform gas-liquid separation.

[3] The method for gasifying organic waste according to [1] or [2], further comprising a step of adding a lower alcohol or a lower carboxylic acid to the object to be treated.

[4] Catalyst for promoting decomposition of organic waste in water having a bulk density of 1 to 8 g / cm ³ , porous particles and containing metal at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. .
[5] The catalyst according to [4], wherein the metal is nickel.
[6] Before or after performing the gasification method according to any one of [1] to [3], a lower alcohol aqueous solution or a lower carboxylic acid aqueous solution is applied at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. A method for activating a catalyst, comprising a step of contacting the catalyst.

[7] A first reaction layer for pressurizing and heating an object to be treated containing organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C.
The pressed and heated workpiece is brought into contact with a porous granular metal-containing catalyst having a bulk density of 1 to 8 g / cm ³ at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification apparatus comprising: a decomposition reaction layer for decomposing waste; and a separator for performing gas-liquid separation by depressurizing or cooling an object to be processed containing the decomposition product.

[8] A first reaction layer for pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C.
A second reaction layer for reducing the molecular weight of organic waste by bringing the pressurized and heated workpiece into contact with activated carbon at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
An object to be treated containing organic waste reduced in molecular weight has a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification apparatus comprising: a decomposition reaction layer for bringing organic waste into contact with each other; and a separator for performing gas-liquid separation by reducing or cooling a material to be treated containing the decomposition product under reduced pressure.

  According to the method of the present invention, organic waste that may be generated in a small amount or intermittently can be gasified at low cost and high efficiency. In addition, according to the method of the present invention, the catalyst life is extended, and the cost caused by recharging the catalyst can be suppressed. Further, the catalyst life can be further extended by the catalyst activation method of the present invention.

It is a figure which shows the gasification apparatus of the organic waste which concerns on one Embodiment of this invention. It is a figure which shows one Embodiment of the reactor used for this invention. It is a figure which shows transition of the gas amount produced | generated by the gasification performed in the Example and the comparative example.

  The present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to the embodiments described below, and modifications, additions, and omissions of the configuration are also included in the technical scope of the present invention without departing from the gist of the present invention.

Embodiment 1
In the method for gasifying organic waste according to Embodiment 1 of the present invention, an object to be treated containing organic waste and water is pressurized and heated at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. The step of starting a hydrothermal reaction without contacting the catalyst, the pressurized and heated object to be treated having a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst and a pressure of 1.5 MPa It has a step of decomposing organic waste by bringing it into contact at -50 MPa and a temperature of 200-500 ° C., and a step of gas-liquid separation by depressurizing or cooling the object to be treated containing the decomposition product.

  Examples of organic waste include waste plastics, waste rubber, shredder dust, livestock manure, garbage, beer lees, sake lees, soy sauce lees, shochu lees, blood mixed wastes, sewage sludge, antigen antibody culture wastes, etc. . Large solid organic waste is crushed to an appropriate size as required. In order to provide a gasification method or gasification apparatus according to an embodiment of the present invention, an organic waste is dispersed, suspended, emulsified, or dissolved in water to obtain an object to be treated containing the organic waste and water. be able to. The obtained object to be processed is stored in the tank 4, for example. The workpiece extracted from the tank 4 is pressurized by the pressurizing pump 2. The applied pressure is 1.5 MPa to 50 MPa, preferably 5 MPa to 30 MPa, more preferably 10 MPa to 25 MPa. The critical pressure of water is 22.06 MPa.

  The object to be processed pressurized by the pressure pump is supplied into the first reaction zone (or first reaction layer) 1 a of the reactor 1. The first reaction zone 1a shown in FIG. 1 has a cavity inside and is not filled with anything. The liquid in the first reaction zone 1a has a pressure of 1.5 MPa to 50 MPa, a temperature of 200 to 500 ° C., preferably 300 to 450 ° C., more preferably 340 to 400 ° C. by pressurization and heating. In addition, the critical temperature of water is 274.1 degreeC. By setting such pressure and temperature, the water in the first reaction zone 1a becomes subcritical water or supercritical water. Hydrothermal reaction of organic waste is initiated by contact with subcritical water or supercritical water. In the first reaction zone, part of the organic waste is decomposed to lower the molecular weight.

Next, the pressurized and heated liquid is supplied into the decomposition reaction zone (or decomposition reaction layer) 1 c of the reactor 1. The decomposition reaction zone 1c shown in FIG. 1 has a cavity inside and is filled with a catalyst. The catalyst to be filled preferably has a bulk density of 1 to 8 g / cm ³ , more preferably 2 to ⁵ g / cm ³ . The bulk density is an apparent density calculated by putting a known mass of catalyst in a graduated cylinder and measuring its apparent volume. The catalyst is preferably porous and granular. The porosity is preferably 20 to 90%, more preferably 35 to 85%, and still more preferably 50 to 80% as a value measured by a water displacement method. Further, the catalyst contains a metal. Metals include nickel, aluminum, zinc, magnesium, tin, silicon, titanium, zirconium, hafnium, rhenium, copper, gold, silver, platinum, rhodium, palladium, iridium, ruthenium, iron, cobalt, tungsten, molybdenum, manganese, Examples include chrome. Of these, those containing nickel are preferred. A specific example of such a catalyst is Raney nickel catalyst. The Raney nickel catalyst is formed by dissolving and removing all or part of a metal other than nickel from an alloy (Raney nickel alloy) composed of nickel and another metal. The content of the other metal component is preferably 1 to 50% by weight, more preferably 2 to 30% by weight, based on nickel in the Raney nickel catalyst. The Raney nickel catalyst is preferably composed of crystal particles having a size of 10 angstroms to 100 angstroms. Also, the catalyst used in the present invention preferably has a BET specific surface area of 10m ² / g~100m ² / g. The catalyst used in the present invention may be supported on a carrier. Examples of the carrier include silica, alumina, magnesia, titania and the like. Of these, it is preferable that the carrier does not elute under hydrothermal conditions. The size of the catalyst is appropriately set from the viewpoint of ease of filling the reactor. The pressure in the decomposition reaction zone is 1.5 MPa to 50 MPa, preferably 5 MPa to 30 MPa, more preferably 10 MPa to 25 MPa, and the temperature is 200 to 500 ° C., preferably 300 to 450 ° C., more preferably 340 to 400 ° C. . In the decomposition reaction zone, the organic waste is further decomposed, and low molecular compounds such as H ₂ , CO ₂ , and CH ₄ are generated.

The capacity and residence time of the first reaction zone and the decomposition reaction zone can be appropriately set according to the type of organic waste, pressure, and temperature.
In the gasifier shown in FIG. 1, a pressure holding valve 3 is provided downstream of the reactor 1. The pressure in the reactor 1 can be maintained at a predetermined value by the holding valve. The workpiece discharged from the reactor 1 is cooled or depressurized. The decomposition product is vaporized by cooling or decompression. The gas-liquid separator 5 separates the gas and the liquid. The divided gas is supplied to the next process through the pipe 7. Since the gas passing through the pipe 7 contains combustible gas such as H ₂ and CH _4, it can be used as fuel. On the other hand, the separated liquid is supplied to the next process through the pipe 6. The liquid passing through the pipe 6 is almost colorless and transparent water. This water can be returned to the tank 4 and reused as water mixed with organic waste.

[Embodiment 2]
In the method for gasifying organic waste according to Embodiment 2 of the present invention, an object to be treated containing organic waste and water is pressurized and heated, and a catalyst is produced at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. Alternatively, the step of starting a hydrothermal reaction without contacting activated carbon, the object to be treated that has been pressurized and heated is brought into contact with activated carbon at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. to reduce the organic waste to a low molecular weight Process, a low molecular weight organic waste to be treated having a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst, a pressure of 1.5 MPa to 50 MPa, and a temperature of 200 to A step of decomposing the organic waste by contacting at 500 ° C., and a step of gas-liquid separation by depressurizing or cooling the object to be treated containing the decomposition product.

Embodiment 2 differs from Embodiment 1 in that it has a second reaction zone (second reaction layer) 1b. That is, as shown in FIG. 2, a second reaction zone (second reaction layer) 1b is provided after the first reaction zone 1a and before the decomposition reaction zone 1c. The second reaction zone 1b has a cavity inside and is filled with activated carbon. The activated carbon preferably has a bulk density of 0.5 to 8 g / cm ³ . The specific surface area of the activated carbon is preferably 10 to 5000 m ² / g. The pressure in the second reaction zone is 1.5 MPa to 50 MPa, preferably 5 MPa to 30 MPa, more preferably 10 MPa to 25 MPa, and the temperature is 200 to 500 ° C., preferably 300 to 450 ° C., more preferably 340 to 400 ° C. is there. In the second reaction zone, radicals are captured, and organic waste is further decomposed to further reduce the molecular weight.
The capacity and residence time of the first reaction zone, the second reaction zone, and the decomposition reaction zone can be appropriately set according to the type of organic waste, pressure, and temperature.

[Stopping and starting the gasifier]
Organic waste may occur constantly, but may occur in small amounts or intermittently.
A tank 8 shown in FIG. 1 stores a lower alcohol aqueous solution or a lower carboxylic acid aqueous solution. When all of the organic waste in the tank 4 is exhausted or when the gasifier is stopped for business reasons, the switching valve 9 is turned to close the port of the piping connected to the tank 4 and to the tank 8. The opening of the connected piping is opened, and a lower alcohol aqueous solution or a lower carboxylic acid aqueous solution is supplied from the tank 8 to the reactor 1. At this time, the pressure in the reactor 1 is 1.5 MPa to 50 MPa, preferably 5 MPa to 30 MPa, more preferably 10 MPa to 25 MPa, and the temperature of the reactor 1 is 200 to 500 ° C., preferably 300 to 450 ° C. Preferably it is 340-400 degreeC. The tar-like substance produced by the hydrothermal reaction and the organic waste that could not be reduced in molecular weight adhered to the inner surface of the reactor 1 or the surface of the activated carbon or the catalyst by the lower alcohol aqueous solution or lower carboxylic acid aqueous solution supplied to the reactor 1 Things can be removed. In addition, the surface of the catalyst is somewhat oxidized by the hydrothermal reaction. When the lower alcohol aqueous solution or the lower carboxylic acid aqueous solution is supplied from the tank 6 to the reactor 1, the lower alcohol aqueous solution or the lower carboxylic acid aqueous solution is decomposed to generate hydrogen. The catalyst is effectively activated by the reduction action of hydrogen. Next, while the supply of the lower alcohol aqueous solution or the lower carboxylic acid aqueous solution from the tank 8 is continued, the pressure in the reactor 11 is reduced and cooled to lower the pressure and temperature to a state where no hydrothermal reaction occurs. When the operation of the gasifier according to the present invention is stopped in this manner, catalyst deterioration can be suppressed and the catalyst life can be extended.

When starting the gasifier, first, a lower alcohol aqueous solution or a lower carboxylic acid aqueous solution is supplied from the tank 8 to the reactor 1, the pressure and temperature of the reactor 1 are increased, and the pressure of the reactor 1 is increased to 1. The temperature of the reactor 1 is set to 200 to 500 ° C., preferably 300 to 450 ° C., more preferably 340 to 400 ° C., to 5 MPa to 50 MPa, preferably 5 MPa to 30 MPa, more preferably 10 MPa to 25 MPa. Then, the switching valve 9 is turned to close the port of the pipe connected to the tank 8, open the port of the pipe connected to the tank 4, and the object to be treated including organic waste and water is supplied from the tank 4 to the reactor 1. Thus, when the operation of the gasifier according to the present invention is started, it is possible to suppress the thermal decomposition product of the organic waste from being deposited near the entrance of the reactor 1, and further to suppress the deterioration of the catalyst, thereby extending the catalyst life. Can be extended.
The concentration of the lower alcohol aqueous solution or the lower carboxylic acid aqueous solution stored in the tank 8 is not particularly limited. For example, the concentration of the lower alcohol or the lower carboxylic acid can be 0.1 to 10% by volume. Examples of the lower alcohol include methanol, ethanol, propanol and the like. Examples of the lower carboxylic acid include formic acid and acetic acid.

[Activation of catalyst]
In the present invention, it is preferable to add a lower alcohol or a lower carboxylic acid to the object to be treated in the tank 4 or upstream from the inlet of the reactor 1. When a lower alcohol or a lower carboxylic acid is supplied to the reactor 1 together with an object to be treated, hydrogen is generated in the reactor 1. This hydrogen can reduce the surface of the catalyst to activate the catalyst and greatly extend the life of the catalyst. The amount of the lower alcohol or the lower carboxylic acid added to the object to be treated is not particularly limited. For example, the concentration of the lower alcohol or the lower carboxylic acid can be 0.1 to 10% by volume.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Comparative Example 1
The inner space of a tubular reactor having a length of 150 mm, an inner diameter of 8.5 mm, and a pressure resistance of 30 MPa was filled with a nickel catalyst to form a catalyst layer having a length of 150 mm.
Pure water was pressurized to 22.5 MPa and supplied to the reactor so that the catalyst layer average residence time was 0.36 minutes in the supercritical state. In the reactor, pure water was heated to 400 ° C. to a supercritical state. While maintaining the pressure and temperature of the reactor, the valve is switched, and an average dispersion time of the catalyst layer becomes 0.36 minutes in a supercritical state with an aqueous dispersion of 10% by weight of shochu instead of pure water in the reactor. The aqueous dispersion was brought into a supercritical state. The supplied aqueous dispersion was a white turbid liquid. Supercritical water discharged from the reactor outlet was cooled and decompressed, and separated into gas and liquid by a separator. The amount of gas produced was measured. The obtained liquid was colorless and transparent. The amount of gas generated at the start of the supply of the aqueous dispersion was about 45 ml / min (25 ° C., 1 atm). The amount of gas produced after 12 hours from the start of supplying the aqueous dispersion was about 3 ml / min. FIG. 3 shows the transition of the gas generation amount. After 12 hours from the start of the supply of the aqueous dispersion, the valve was switched while maintaining the pressure and temperature of the reactor, and pure water was supplied instead of the aqueous dispersion of shochu. The supply of pure water was stopped when the temperature and pressure were lowered while the pure water was supplied to release the hydrothermal state. The reactor was opened and the inside was observed. A heat denatured product of the shochu accumulated at the inlet of the reactor and blocked the reactor inlet. The surface of the nickel catalyst was oxidized.

Example 1
The inside of a tubular reactor having a length of 650 mm, an inner diameter of 8.5 mm, and a pressure resistance of 30 MPa is filled with a porous granular Raney nickel catalyst having a bulk density of 4.1 g / cm ³ , and a catalyst layer having a length of 150 mm is placed on the outlet side of the reactor The entrance side of the catalyst layer was partitioned with a steel net, and the entrance side of 500 mm was made hollow.

(Starting operation)
A 3% by volume aqueous methanol solution was pressurized to 22.5 MPa and supplied to the reactor so that the catalyst layer average residence time was 0.36 minutes in the supercritical state. In the reactor, the methanol aqueous solution was heated to 400 ° C. to be in a supercritical state. While maintaining the pressure and temperature of the reactor, the valve is switched to replace the methanol aqueous solution with an aqueous dispersion of 10% by mass of shochu so that the catalyst layer average residence time becomes 0.36 minutes in a supercritical state in the reactor. The aqueous dispersion was brought into a supercritical state. Supercritical water discharged from the reactor outlet was cooled and decompressed, and separated into gas and liquid by a separator. The amount of gas produced was measured. The obtained liquid was colorless and transparent.

(Stop operation)
When 12 hours passed from the start of the supply of the aqueous dispersion, the valve was switched while maintaining the pressure and temperature of the reactor, and a 3% by volume aqueous solution of methanol was supplied instead of the aqueous dispersion of shochu. The temperature and pressure were lowered while the aqueous solution was supplied, and the supply of the aqueous solution was stopped when the hydrothermal state was removed.
After 10 hours had passed since the supply of the aqueous dispersion was stopped, the above start operation and stop operation were repeated.

  The amount of gas generated at the start of actual operation (first supply of aqueous dispersion) is about 68 ml / min (25 ° C., 1 atm), the amount of gas generated after 12 hours of actual operation is about 30 ml / min, and the actual operation is 24 hours. The amount of gas produced during the lapse of time was about 25 ml / min, and the amount of gas produced after 100 hours of actual operation was about 10 ml / min. FIG. 3 shows the transition of the gas generation amount. After 100 hours of actual operation, the operation was stopped and the reactor was opened. Although the surface of the catalyst was slightly oxidized, almost no heat-modified product of shochu was observed.

Example 2
The inside of a tubular reactor having a length of 650 mm, an inner diameter of 8.5 mm, and a pressure resistance of 30 MPa is filled with a porous granular Raney nickel catalyst having a bulk density of 4.1 g / cm ³ , and a catalyst layer having a length of 150 mm is placed on the outlet side of the reactor And the entrance side of the catalyst layer was partitioned with a steel net. Next, activated carbon was filled with a bulk density of 0.27 g / cm ^{3, and an} activated carbon layer having a length of 150 mm was formed on the entrance side of the catalyst layer, the entrance side of the activated carbon layer was partitioned with a steel net, and the entrance side 350 mm was hollow.
Gasification of shochu was performed by the same method as in Example 1 except that the above tubular reactor was used instead of the tubular reactor used in Example 1, and the amount of gas produced was measured. The obtained liquid was colorless and transparent. The amount of gas produced at the start of actual operation was about 50 ml / min (25 ° C., 1 atm). The amount of gas produced after 120 hours of actual operation was about 10 ml / min, and the amount of gas produced after 160 hours of actual operation was about 8 ml / min. FIG. 3 shows the transition of the gas generation amount. The operation was stopped and the reactor was opened. The surface of the catalyst was slightly oxidized. No heat-denatured shochu was found. The catalyst life was slightly increased as compared with Example 1.

Example 3
The inside of a tubular reactor having a length of 930 mm, an inner diameter of 8.5 mm, and a pressure resistance of 30 MPa is filled with a porous granular Raney nickel catalyst having a bulk density of 4.1 g / cm ³ , and a catalyst layer having a length of 150 mm is placed on the outlet side of the reactor. And the entrance side of the catalyst layer was partitioned with a steel net. Next, activated carbon having a bulk density of 0.27 g / cm ³ was filled, and an activated carbon layer having a length of 180 mm was formed on the inlet side of the catalyst layer, and the inlet side of the activated carbon layer was partitioned with a steel net, and the inlet side of 600 mm was made hollow. .
Instead of the tubular reactor used in Example 1, the above tubular reactor was used, and an aqueous dispersion containing 10% by mass of shochu and 3% by volume of methanol was substituted for an aqueous dispersion of 10% by mass of shochu. Gasification of shochu was performed in the same manner as in Example 1 except that it was used, and the amount of gas produced was measured. The obtained liquid was colorless and transparent. The amount of gas produced at the start of actual operation was about 50 ml / min (25 ° C., 1 atm). The amount of gas produced after 100 hours of actual operation was about 30 ml / min, and the amount of gas produced after 180 hours of actual operation was about 30 ml / min. FIG. 3 shows the transition of the gas generation amount. The operation was stopped and the reactor was opened. The surface of the catalyst was hardly oxidized. No heat-denatured shochu was found. The catalyst life has become much longer.

1: Reactor 1a: Cavity 1b: Activated carbon filling part 1c: Metal catalyst filling part 2: Pressurizing pump 3: Relief valve (holding pressure valve)
4: Organic waste tank 5: Gas-liquid separator 6: Treated liquid 7: Decomposition gas 8: Tank of lower alcohol aqueous solution or lower carboxylic acid aqueous solution 9: Change valve (flow path switching valve)

Claims (8)

A step of pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
The pressed and heated workpiece is brought into contact with a porous granular metal-containing catalyst having a bulk density of 1 to 8 g / cm ³ at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification method comprising: a step of decomposing waste; and a step of gas-liquid separation by depressurizing or cooling an object to be treated containing the decomposition product. A step of pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
A step of reducing the molecular weight of the organic waste by bringing the pressurized and heated workpiece into contact with activated carbon at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
An object to be treated containing organic waste reduced in molecular weight has a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification method comprising: a step of decomposing organic waste by contacting, and a step of depressurizing or cooling an object to be treated containing the decomposition product to perform gas-liquid separation.   The organic waste gasification method according to claim 1, further comprising a step of adding a lower alcohol or a lower carboxylic acid to the object to be treated. A catalyst for promoting the decomposition of organic waste in water having a bulk density of 1 to 8 g / cm ³ , porous particles and containing metal, at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C.   The catalyst according to claim 4, wherein the metal is nickel.   A step of bringing a lower alcohol aqueous solution or a lower carboxylic acid aqueous solution into contact with a catalyst at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C before or after performing the gasification method according to any one of claims 1 to 3. The activation method of the catalyst which has. A first reaction layer for pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C;
The pressed and heated workpiece is brought into contact with a porous granular metal-containing catalyst having a bulk density of 1 to 8 g / cm ³ at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification apparatus comprising: a decomposition reaction layer for decomposing waste; and a separator for performing gas-liquid separation by depressurizing or cooling an object to be processed containing the decomposition product. A first reaction layer for pressurizing and heating an object to be treated including organic waste and water to start a hydrothermal reaction at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C;
A second reaction layer for reducing the molecular weight of organic waste by bringing the pressurized and heated workpiece into contact with activated carbon at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C .;
An object to be treated containing organic waste reduced in molecular weight has a bulk density of 1 to 8 g / cm ³ , a porous granular metal-containing catalyst at a pressure of 1.5 MPa to 50 MPa and a temperature of 200 to 500 ° C. An organic waste gasification apparatus comprising: a decomposition reaction layer for bringing organic waste into contact with each other; and a separator for performing gas-liquid separation by reducing or cooling a material to be treated containing the decomposition product under reduced pressure.

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