JP3544442B2 - Catalyst purification device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for purifying contaminated air, and more particularly, to a catalyst for efficiently removing malodorous gas and / or volatile organic compounds in air while suppressing NO _X emissions by using a catalyst. It relates to a purification device.
[0002]
[Prior art]
Conventionally, it absorbs not only exhaust gas from chemical plants and automobiles but also air pollution caused by generation of odorous gas and volatile organic compounds in food processing, resin processing, printing, painting, soil restoration, etc. BACKGROUND ART Purification is performed by using various techniques such as combustion, absorption, catalytic oxidation, and biological deodorization singly or in combination.
[0003]
Among these, the catalytic oxidation method involves heating the entire contaminated air to 150 to 500 ° C. with a burner or a heater, and then oxidizing the contaminated air in a reaction chamber having a catalyst. However, there is a disadvantage that running cost, installation area, and initial cost are increased.
In the case of burners using kerosene and city gas as fuel, on the NO _X occurs, there is a drawback that a large amount causes global warming since CO ₂ is generated.
[0004]
[Problems to be solved by the invention]
Therefore, the present inventors have conducted intensive studies to solve the above-mentioned drawbacks and found that good results can be obtained by performing normal operation without a burner using an exothermic oxidation reaction using a catalyst. The present invention has been found.
Therefore, an object of the present invention is to provide a catalyst purification device for purifying air contaminated with malodorous gas and / or volatile organic compounds, which generates a small amount of NO _X and CO ₂ .
[0005]
[Means for Solving the Problems]
It is an object of the present invention to provide a catalyst purification apparatus in which harmful gas contained in air to be purified containing malodorous gas and / or volatile organic compounds is burned and purified using a catalytic reactor to produce high-temperature purified air. Te, at least, a heat exchanger for preheating the purification target air purifier air in the high temperature, a preheater used on startup, combustibles supply means, a harmful compound combustion to produce a product other than water and carbon dioxide achieve the pretreatment catalytic reactor for processing, and the harmful gas combustion and purification to the catalytic reactor to hot purified air, by the catalytic purification device which the purified air, characterized in that the flow in this order Was done.

[0006]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating a configuration of a catalyst purification device of the present invention.
In the figure, reference numeral 1 denotes a filter for removing solid matter such as dust in the air to be purified, 2 denotes a fan, 3 denotes a heat exchanger, 4 denotes a preheater used at startup, and 5 denotes a vaporizer. A combustible material supply means 6 may be a catalyst reactor, and 7 may be a control device for efficiently operating the catalyst purification device.

[0007]
In the present invention, the offensive odor gas means a gas having an odor generated from a gas source such as a car, a factory, a river, or the like, mixed into the air and contaminating the air, and is not particularly limited.
The volatile organic compound (VOC) is a volatile organic compound that is not contained in natural air and is generated from benzene, toluene, gasoline, and other similar sources. There are 284 harmful air pollutants for which the Environment Agency is considering regulations, of which about 130 are VOCs.
[0008]
The purifying apparatus of the present invention purifies these contaminants by oxidizing and burning them using a catalytic reactor, on the premise that catalytic combustion is an exothermic reaction. Therefore, the polluted air to be purified in the present invention is air having flammable pollutant gas, but air polluted with hydrocarbon-based harmful gas such as benzene and toluene that emits a large amount of reaction heat during combustion. The apparatus of the present invention is particularly effective in purifying wastewater.
[0009]
The catalyst reactor in the present invention can be appropriately selected from known ones. In particular, from the viewpoint of small size and excellent energy efficiency, a heat exchanger as described in Japanese Utility Model Publication No. 8-4104 is used. It is preferred to use an exothermic reactor that also serves.
In addition, the catalyst supported by such a catalyst reactor is appropriately selected from known catalysts that are effective in the combustion reaction of combustible harmful substances to be removed and contained in the target air to be purified. You can choose.
[0010]
In the apparatus of the present invention, in order to efficiently remove the harmful substances, a flammable material supply means such as a branch pipe having a valve is disposed at the front stage of the catalytic reactor, and if necessary, the flammable substance is supplied to the air to be purified. A combustible material such as hydrocarbons such as butane and propane that can generate combustion heat is supplied.
In this case, as a combustible, supplying a liquid such as a petroleum solvent, toluene, or kerosene improves the thermal efficiency as a whole, and therefore, in the present invention, particularly, a vaporizer is provided in the combustible supply means, It is preferable to supply a liquid combustible.
[0011]
If the air to be purified contains a compound containing an element such as a halogen atom or sulfur, it not only damages the catalytic reactor, but also emits harmful substances after combustion. Preferably, a pretreatment catalyst reactor (not shown) using, for example, a compound containing an element such as cobalt, molybdenum, or manganese is disposed between the combustible material supply means 5 and the catalyst reactor 6.

[0012]
When purifying contaminated air using the catalyst purifying apparatus of the present invention, first, a burner or an electric heater, preferably a preheater using a burner and the fan 2 are operated simultaneously or in sequence. Either the preheater or the fan may be operated first. When combustibles such as kerosene, benzene, and toluene are supplied to the preheated contaminated air via the combustibles supply means 5 as needed, the combustion reaction in the catalytic reactor becomes active, and this reaction causes The generated combustion heat heats the catalytic reactor, which further promotes the combustion reaction.

[0013]
The heating by the preheater 4 is stopped when it is determined that the catalytic reactor is heated and the catalytic reaction is sufficiently performed. The high-temperature purified air discharged from the catalytic reactor is discharged outside the purifying device of the present invention after heating the purified air in the heat exchanger 3 (the purified air is preheated by this).
The control device 7 controls the temperature of the preheater 4, the supply amount of combustible material from the combustible material supply device 5, the total gas flow rate at that time, the temperature of the catalyst reactor 6, and the contamination in the air before and after the catalyst reactor. By detecting the content of the substance and the like, the supply amount of the combustible material is controlled so that the processing capacity and efficiency of the entire purification device are optimized.

[0014]
As the combustibles, as described above, it is preferable to use benzene, toluene, or the like having a large calorific value at the time of combustion. However, as the combustibles, it is preferable to use a solvent recovery liquid discharged from a factory or the like. It is particularly preferable from the viewpoint of reducing the running cost of the purification device.
As described above, in the apparatus of the present invention, there is no need to operate the preheater except at the time of start-up. Therefore, a conventional catalyst purification apparatus in which harmful gas is burned by a burner and exhaust gas is post-processed using a catalyst reactor. Energy loss is reduced as compared to (FIG. 2), which can reduce operating costs.
Furthermore, since it is not necessary to raise the temperature as in the case of combustion by a burner, the generation of thermal NO _X is extremely small.
Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[0015]
【Example】
In the purifying apparatus of the present invention shown in FIG. 1, when purifying air containing 50 ppm of methyl alcohol at a space velocity of 10 nm ³ / min, a heat pipe type heat exchanger having a size of 253 × 610 × 184 (mm 3) is used as a heat exchanger. A honeycomb-type catalytic reactor with a size of 150 × 150 × 50 (mm 3) using a thermo coil made of Showa aluminum, using a burner as a preheater, and carrying platinum as a catalyst on a wall as a catalytic reactor. The heat balance was calculated as follows when toluene was supplied from the combustible material supply means so that the purified air contained 1,500 ppm of toluene as a combustible material.

[0016]
{Circle around (1)} Toluene combustion reaction: C ₆ H ₅ CH ₃ + 9O ₂ → 4H ₂ O + 7CO ₂ +901.5 (kcal / g · mol)
{Circle around (2)} Amount of toluene in contaminated air: (1500 × 10 ⁻⁶ /22.4)=0.0669 (g · mol / nm ³ )
{Circle around ( ³ )} Calorific value when purifying contaminated air: 901.5 × 0.0669 = 60.3 (kcal / nm ³ )
{Circle around (4)} Temperature difference (Δt) between contaminated air before and after the catalytic reactor: 60.3 / 0.31 = 194.0 (° C.). However, the specific heat of air was set to 0.31 (kcal / nm ³ ).
[0017]
Therefore, when the temperature of the contaminated air at the inlet of the catalytic reactor is 300 ° C., the temperature of the purified air is 494 ° C. However, the average heat exchange rate of the heat pipe heat exchanger is 0.65, Heat exchange of the contaminated air to 300 ° C., ie the temperature of the contaminated air at the inlet of the catalytic reactor is maintained at 300 ° C.
As described above, even when self-combustion cannot be realized only by harmful hydrocarbons or the like in the polluted air to be purified, toluene may be supplied from the combustible material supply means so that, for example, toluene in the contaminated air becomes about 1500 ppm. .
If benzene is used instead of toluene, the same cycle can be maintained without a burner if the benzene is about 1700 ppm.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
The catalyst purifying apparatus of the present invention is characterized in that at least a heat exchanger, a preheater, a combustible material supply unit , a pretreatment catalytic reactor, and a catalytic reactor are cleaned by the high-temperature purified air discharged from the catalytic reactor. It is obtained by connecting sequentially so as to be preheated via a heat exchanger. The introduction of the air to be purified may be performed by disposing a fan having a filter in front of the heat exchanger, or by using a compressor or the like.
[0019]
【The invention's effect】
The catalyst purifying apparatus of the present invention has an advantage that the operating cost is low because a burner is not used except at the time of start-up, and the generation of NO _X is extremely small because the temperature in the reactor during combustion is low.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing one embodiment of a catalyst purification device of the present invention.
FIG. 2 is a conceptual diagram of a conventional catalyst purifying apparatus using a burner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Filter 2 Fan 3 Heat exchanger 4 Preheater 5 Combustibles supply means 6 Catalytic reactor 7 Control device 8 Burner

Claims (4)

A catalyst purifying apparatus that burns and purifies harmful gas contained in air to be purified containing malodorous gas and / or volatile organic compounds by using a catalytic reactor to produce high-temperature purified air, at least comprising: heat exchanger for preheating the air purifier air in the high temperature, a preheater used on startup, combustibles supply means, a combustion pretreated for treating deleterious compound generating product other than water and carbon dioxide gas by burning-purifying catalytic reactor and the harmful gas catalytic reactor to hot purified air, the catalytic purification device which the purified air, characterized in that the flow in this order. The catalyst purification device according to claim 1, wherein the heat exchanger is a heat pipe heat exchanger. 3. The catalyst purifying device according to claim 1, wherein a vaporizer is provided in the combustible material supply unit.   The catalyst purification according to any one of claims 1 to 3, wherein the pretreatment catalyst reactor is a pretreatment catalyst reactor using a catalyst comprising at least one element selected from cobalt, molybdenum, and manganese. apparatus.

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