JPH11253800A - Gaseous noxious component removing catalyst and gas treatment process using catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decompose and remove noxious gas at a normal temperature. SOLUTION: A reducer 4 is reacted with a nitrogen oxide to reduction remove the nitrogen oxide by using a catalyst 6 carrying one kind or two kinds of metal components or more selected out of a group formed of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide and cerium oxide for active carbon fibers carrying one kind of two kinds of metal components or more selected out of a group formed of platinum, palladium, ruthenium, platinum oxide, palladium oxide and ruthenium oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for removing harmful gas and a method for treating gas using the catalyst.

[0002]

2. Description of the Related Art Hazardous gas generated in combustion plants, garbage incineration-related plants and tunnels causes environmental pollution if released directly into the atmosphere. Therefore, it is necessary to remove harmful gases.

Conventionally, there are many known methods for removing harmful gases, and representative methods are as follows.

For example, as a method for decomposing and removing nitrogen oxides such as harmful gases such as nitric oxide, nitrogen dioxide and nitrous oxide, titanium oxide, zeolite and activated carbon carrying metal oxide at a temperature of 200 to 450 ° C. There is a method of decomposing and removing nitrogen oxides by reacting with a reducing agent such as ammonia and hydrocarbon under a certain catalyst.

[0005] Further, as a method for removing organic chlorine compounds and organic compounds such as dioxin which is another harmful gas,
At a temperature of 150 to 300 ° C., an organic chlorine compound or an organic compound is formed using a catalyst of titanium oxide, alumina or silicon dioxide supporting a noble metal oxide such as platinum or a catalyst of titanium oxide supporting an oxide of vanadium, molybdenum or tungsten. There are methods of catalytic decomposition or oxidative decomposition.

Further, there is a method of decomposing and removing the harmful gas using an electron beam, ozone, corona, or the like.

[0007]

However, a method of decomposing and removing nitrogen oxides by using a catalyst and a reducing agent of titanium oxide, zeolite and activated carbon supporting metal oxide as described above,
In a method of removing an organic chlorine compound or an organic compound using a catalyst of titanium oxide, alumina, or silicon dioxide supported on a noble metal oxide or a catalyst of titanium oxide supported on an oxide of vanadium, molybdenum, or tungsten, a temperature of from room temperature to 150 ° C.
In the following, the harmful gas cannot be decomposed, and the harmful gas is released into the atmosphere as it is, which may pollute the environment. In addition, in order to remove the above-mentioned nitrogen oxides, organic chlorine compounds, and organic chlorine compounds, 150
A temperature of about 450 ° C. is required, and the equipment becomes expensive. In addition, the method using an electron beam, ozone, and a corona is expensive, so that the cost is increased.

An object of the present invention is to provide a catalyst for removing harmful components of a gas which can decompose a harmful gas at a temperature from normal temperature to 150 ° C. or lower, and a method for treating a gas using the catalyst.

[0009]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have completed a very industrially advantageous catalyst for removing gaseous components and a method for removing gaseous components. Reached.

That is, a group consisting of platinum, palladium, ruthenium, platinum oxide, palladium oxide, and ruthenium oxide;
In addition, any of the group consisting of copper, iron, chromium, copper oxide, iron oxide, and chromium oxide, and a group consisting of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide, and cerium oxide It is intended to provide a method for treating a gas capable of decomposing harmful gases by using an activated carbon fiber catalyst supporting one or more metal components selected from the group consisting of:

The outline of the apparatus used in the gas treatment method of the present invention is as follows.
A box-shaped catalytic reactor through which exhaust gas can pass is provided in the middle of the chimney, which has a temperature of ℃, and in the ventilation holes of tunnels with a high concentration of nitrogen oxides. This is provided with a nozzle for injecting a reducing agent drawn from the inside, and a catalyst is accommodated inside the catalytic reaction device.

Another apparatus used in the gas treatment method of the present invention is as follows. An exhaust gas containing a harmful gas from a factory is discharged at a temperature of 10 to 100 ° C. in a middle part of a discharge pipe or a refuse incinerator. Exhaust gas containing harmful gas is 10 to 10
A box-shaped catalytic reactor capable of passing exhaust gas is provided in the middle of the chimney at a temperature of 0 ° C. A catalyst is accommodated inside the catalytic reactor.

As an example of the catalyst housed inside the catalytic reactor, one or more metals selected from the group consisting of platinum, palladium, ruthenium, platinum oxide, palladium oxide and ruthenium oxide are formed on activated carbon fibers. What carried the component, or copper, iron, chromium, on activated carbon fiber
1 selected from the group consisting of copper oxide, iron oxide, and chromium oxide
One or two or more metal components supported thereon, and one or two selected from the group consisting of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide, and cerium oxide on activated carbon fibers Some activated carbon fibers carry the above metal components, and each of the activated carbon fibers generally has a surface area of 1
2,000 m ² / g or more, preferably 1500 m ² / g
g or more, the metal component supported on the activated carbon fiber,
Each is in a weight ratio of 0.1 to 20% with respect to the activated carbon fiber.

[0014] Further, the catalyst is not the above, and is a group consisting of platinum, palladium, ruthenium, platinum oxide, palladium oxide and ruthenium oxide, and a group consisting of copper, iron, chromium, copper oxide, iron oxide and chromium oxide. Among them, activated carbon fibers carrying one or more metal components selected from any group, further from vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide, cerium oxide When the activated carbon fiber has one or more metal components selected from the group consisting of, the activated carbon fiber has the same surface area as described above, and a plurality of metal components supported on the activated carbon fiber. The total is 0.1 to 20% by weight based on the activated carbon fibers.

Further, all the catalysts shown above are:
A plurality of metal components supported on the activated carbon fibers may be alloyed in advance so that the distribution of the metal components supported on the activated carbon fibers becomes uniform.

Further, titanium oxide, alumina and zeolite are preliminarily mixed into the activated carbon fiber, and the supported metal component is
The weight ratio may be set to 0.1 to 20% with respect to the activated carbon fiber mixed with titanium oxide, alumina and zeolite.

In the first device shown above, platinum,
Palladium, ruthenium, platinum oxide, palladium oxide,
Activated carbon carrying one or more metal components selected from any of the group consisting of ruthenium oxide and the group consisting of copper, iron, chromium, copper oxide, iron oxide and chromium oxide A catalyst in which one or more metal components selected from the group consisting of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide, and cerium oxide are further supported on fibers, or a plurality of these metal components. Among them, a catalyst in which titanium oxide, alumina, and zeolite are mixed with activated carbon fiber is stored in a catalytic reactor, and a reducing agent and nitrogen oxide are reacted with each other. There is a method for removing oxides.

The reducing agent used in the invention of the method in this case includes ammonia or a lower hydrocarbon gas such as methane, ethylene, ethane or propylene. The harmful gas nitrogen oxides are nitrogen monoxide, nitrogen dioxide, nitrous oxide and the like as in the conventional example.

The reaction temperature may be any temperature at which the process of the present invention can be carried out, but is generally from 0 to 150.
° C, preferably 10 to 100 ° C. If an example of a normal reaction operation mode is shown, at room temperature, a reducing agent is injected into an exhaust gas containing nitrogen oxide which is a harmful gas to form a mixed gas, and the mixed gas is passed through a catalyst to convert the nitrogen oxide into nitrogen. Reduce to water and remove.

Further, in the apparatus described later, one or more metal components selected from the group consisting of copper, iron, chromium, copper oxide, iron oxide and chromium oxide are supported on the activated carbon fiber. The catalyst is stored in the catalytic reactor,
There is also a method of removing odor components.

In this case, the odorous components of the harmful gas decomposed in the present invention include ammonia, mercaptan and the like.

The reaction temperature may be any temperature at which the process of the present invention can be carried out, but is generally from 0 to 150 ° C., preferably from 10 to 1 ° C., as in the case of the nitrogen oxides described above.
00 ° C. An example of a normal reaction operation mode is as follows.
At room temperature, odor components, which are harmful gases, are passed through a catalyst, and the odor components are removed by catalytic decomposition or oxidative decomposition.

Further, in the same device as the odor component,
There is a method in which one of the catalysts in all the cases described above is housed in a reactor to remove an organic chlorine compound and a harmful component of the organic compound.

The organic chlorine compound and the organic compound of the harmful gas decomposed in the invention in this case are dioxin and the like generated from a refuse incinerator or the like.

The reaction temperature may be any temperature at which the method of the present invention can be carried out, but is generally 0 to 150 ° C., preferably 10 to 100 ° C. as in the above-mentioned method.
It is. As an example of a normal reaction operation mode, at normal temperature, an organic chlorine compound and an organic compound, which are harmful gases, are passed through a catalyst, and the organic chlorine compound and the organic compound are removed by catalytic decomposition or oxidative decomposition.

In this way, the harmful gas is removed from normal temperature by 15
Since it can be decomposed and removed at 0 ° C or less, no harmful gas is released into the atmosphere as it is and does not pollute the environment. Also, since expensive facilities and equipment are not required, cost increase is prevented. Can be.

[0027]

Embodiments of the present invention will be described below. The embodiments of the present invention are not limited to the embodiments described below.

(Example 1) When the exhaust gas 1 generated in a combustion plant contains nitrogen oxides of harmful gases, that is, nitrogen monoxide, nitrogen dioxide, nitrous oxide, etc., the apparatus shown in FIG. At room temperature of about 20 ° C.
Ammonia or lower hydrocarbon gas injection nozzle 5
The mixed gas is further injected into the exhaust gas flow path 3 to form a mixed gas, and the mixed gas is passed through the catalyst 6 to decompose nitrogen monoxide, nitrogen dioxide, and nitrous oxide into harmless nitrogen and water and discharge the same to the outside.

(Example 2) When the odorous gas of harmful gas, ie, ammonia, mercaptan, etc., is contained in the exhaust gas 1 generated from the factory, using the apparatus shown in FIG. To pass the exhaust gas 1 through the catalyst 6 in the catalytic reactor 2 to catalytically or oxidatively decompose ammonia, mercaptan, etc., and discharge it as a harmless component to the outside.

(Embodiment 3) When exhaust gas 1 generated from a refuse incinerator contains an organic chlorine compound and an organic compound of harmful gas, that is, dioxin, etc., Embodiment 2
Similarly to the above, the exhaust gas 1 is passed through the catalyst 6 at room temperature of about 20 ° C. using the apparatus shown in FIG. 2 to catalytically or oxidatively decompose dioxins and the like and discharge them as harmless components to the outside.

As described above, since the harmful gas can be decomposed and removed, the harmful gas is not released to the atmosphere as it is and does not pollute the environment. In addition, since expensive facilities and equipment are not required, the cost is reduced. An increase can be prevented.

The embodiment of the present invention is not limited to the above-described embodiment, but a gas cooling device (not shown) is installed on the upstream side of the gas flow path. Thus, the exhaust gas 1 may be rapidly cooled to suppress the generation of the harmful gas in advance, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0033]

According to the present invention, the harmful gas can be decomposed and removed from ordinary temperature to 150 ° C. or less.
The harmful gas is not released to the atmosphere as it is and does not pollute the environment, and expensive facilities and equipment are not required. Therefore, various excellent effects such as an increase in cost can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in which an exhaust gas mixed with a reducing agent is passed through a catalyst provided in a middle part of an exhaust gas passage.

FIG. 2 is a schematic view showing a state in which exhaust gas is passed through a catalyst provided in a middle part of an exhaust gas passage.

[Explanation of symbols]

 4 Reducing agent 6 Catalyst

Claims (9)

[Claims] 1. Removal of harmful gas components, characterized in that activated carbon fibers carry one or more metal components selected from the group consisting of platinum, palladium, ruthenium, platinum oxide, palladium oxide and ruthenium oxide. Catalyst. 2. A method for removing harmful gas components, wherein the activated carbon fiber carries one or more metal components selected from the group consisting of copper, iron, chromium, copper oxide, iron oxide and chromium oxide. Catalyst. 3. An activated carbon fiber carrying one or more metal components selected from the group consisting of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide and cerium oxide. Gas removal catalyst. 4. A material selected from the group consisting of vanadium, molybdenum, tungsten, cerium, vanadium oxide, molybdenum oxide, tungsten oxide, and cerium oxide.
3. The catalyst according to claim 1, further comprising one or more metal components. 5. The catalyst according to claim 1, wherein a plurality of metal components are supported as an alloy. 6. The catalyst according to claim 1, wherein titanium oxide, alumina and zeolite are mixed in the activated carbon fiber in advance. 7. A gas treatment method comprising reacting a reducing agent with nitrogen oxide using the catalyst according to claim 4 to reduce and remove nitrogen oxide. 8. A method for treating a gas, comprising catalytically decomposing or oxidatively decomposing an odor component using the catalyst according to claim 1. 9. A method for treating a gas, comprising catalytically decomposing or oxidatively decomposing an organic chlorine compound and a harmful component of an organic compound using the catalyst according to claim 1, 2, 3, 4, 5, or 6.