JPS63181764A - Deodorizing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention first performs adsorption and collection to deodorize the gas using an adsorption layer that has the adsorption ability and oxidative decomposition ability for malodorous components in gas, and then deodorizes the gas. The present invention relates to a deodorizing method capable of maintaining deodorizing efficacy over a long period of time by intermittently introducing ozone into a gas and oxidizing and decomposing malodorous components collected on an adsorption layer using ozone on the adsorption layer.

<Prior art and its problems> In recent years, odor pollution has been widely discussed as a social problem.
Various new odor control technologies are being developed and implemented.

Conventional deodorization methods include water washing, chemical cleaning, adsorption, direct combustion,
This has been carried out using catalytic combustion methods, oxidation methods using ozone, etc., but each method has its advantages and disadvantages, and they often have practical problems.

That is, although water washing and chemical cleaning methods are simple in terms of equipment, they often have problems with their deodorizing efficiency and the technology for treating waste water that is generated in large quantities, resulting in high treatment costs. Activated carbon is generally used as an adsorbent in the adsorption method, but depending on the conditions, there is a risk of ignition due to the heat of adsorption, and depending on the concentration of malodorous components, the adsorption capacity may be lost in a short period of time, making it necessary to regenerate or replace the activated carbon. etc. are required. As a method for regenerating activated carbon, there is a desorption regeneration method using steam and heated inert gas, but the running cost for deodorization is not cheap as it requires the cost of steam generation, the problem of wastewater treatment, or the cost of inert gas generation and heating. isn't it.

The direct combustion method requires fuel to maintain the temperature inside the furnace at 700 to 900°C, which results in high running costs and
There is also a risk of secondary pollution such as the generation of OX. The catalytic combustion method is relatively easy to maintain the equipment, but the catalyst layer temperature is 200 to 45%.
It is necessary to maintain the condition at 0° C., and if the temperature of the gas to be treated is low or the concentration of combustibles is low, there is a drawback that running costs will be high.

The ozone oxidation method is a method of treating malodorous components by utilizing the strong oxidizing effect of ozone, and since it can be treated even at a low temperature of about air temperature, the running cost is lower than the above-mentioned methods. However, since the reaction between ozone and malodorous components in the gas phase is slow, a long reaction zone is required;
Since unreacted ozone is discharged, it has the disadvantage of causing secondary pollution due to ozone.

Two new methods have been proposed to compensate for the shortcomings of the methods described above. The first method is to deodorize using a device equipped with an ozone generator and an ozone decomposition filter (Japanese Patent Laid-Open No. 61-29358).

In this method, unreacted ozone is decomposed and then exhausted, so there is no need to worry about secondary pollution; however, as ozone and malodorous components are decomposed in the gas phase, the reaction zone becomes large in volume, as mentioned above. Alternatively, if the capacity of the reaction zone is small, the process gas passes through the ozone decomposition filter before being sufficiently deodorized, resulting in a disadvantage that the deodorizing effect is reduced. The second method is a method in which a catalyst is used for the purpose of catalytically reacting ozone and malodorous components to promote the oxidation reaction and at the same time catalytically decomposing unreacted ozone.

The catalyst used in this method is a catalyst in which a metal oxide is supported on a carrier made of carbonaceous material (Japanese Patent Application Laid-Open No. 1193-1983)
No. 71) and a catalyst in which a metal oxide is supported on an activated alumina carrier (Japanese Patent Application Laid-open No. 30978/1983) are disclosed.

In the case of the former catalyst, due to its high ozone decomposition ability, a large amount of ozone is consumed in order to obtain the desired deodorizing effect, and due to the combustion of carbon by ozone, the carrier is consumed and the adsorption capacity is too large, resulting in oxidation generation. It has shortcomings in terms of lifespan, such as adsorption of substances and therefore deterioration of the catalyst.

In the case of the latter catalyst, like the former catalyst, it has a high ozone decomposition ability, so in order to obtain the desired deodorizing effect, a large amount of ozone is consumed. ) is oxidized and becomes SO3 and is accumulated in the activated alumina of the carrier, so it has the disadvantage that a long life cannot be expected.

As described above in detail, it is difficult to achieve a sufficient deodorizing effect and to substantially eliminate the emission of unreacted ozone using the methods of the prior art.

<Object of the Invention> Therefore, an object of the present invention is to provide a deodorizing method that maintains a stable and efficient deodorizing effect over a long period of time when deodorizing malodorous components in gas and has low running costs.

Means for Solving the Problems In order to achieve the above object, the present inventors have completed the present invention as a result of various studies.

In other words, the deodorizing method of the present invention first adsorbs and collects bad odor components in gas using an adsorption layer that has adsorption ability and oxidative decomposition ability, deodorizes the gas, and then removes the bad odor components from the gas until the adsorption ability of the adsorption layer is exceeded. Before this occurs, a certain concentration of ozone is introduced into the gas, and the malodorous acid collected on the adsorption layer is oxidized and decomposed on the adsorption layer by ozone, thereby restoring the adsorption capacity of the adsorption layer over a long period of time. It is characterized by maintaining its deodorizing effect.

The adsorbent installed in the adsorption layer needs to have both the ability to efficiently adsorb and collect malodorous components and the ability to efficiently oxidize and decompose the adsorbed malodorous components by introducing ozone. Activated carbon, which is commonly used as an adsorption deodorizing agent, has an excellent ability to adsorb malodorous components, but when ozone is introduced as a regeneration means, the activated carbon and ozone are removed before the adsorbed malodorous components react with ozone. This reaction not only fails to restore the adsorption capacity of the activated carbon, but also causes the activated carbon itself to be consumed.

As a result of extensive research into adsorbents that have the ability to adsorb malodorous substances and allow the adsorbed substances to be efficiently oxidized and decomposed by ozone, the present inventors have discovered that they can efficiently remove malodorous components from gas. Binary oxides consisting of titanium and silicon, binary oxides consisting of titanium and zirconia, or ternary oxides consisting of titanium, silicon and zirconia have excellent adsorption performance as adsorbents. It was discovered that the introduced ozone causes oxidative decomposition at a low temperature of 50° C. or lower, and the adsorption performance quickly recovers.

Furthermore, manganese (Mo), iron (Fe), cobalt (CO), nickel (Ni), zinc (Zn), silver (Ag), platinum (Pt) is added to the binary oxide or ternary oxide.
An adsorbent containing at least one element selected from the group consisting of , palladium (Pd), and rhodium (Rh), or a compound thereof, has the ability to adsorb malodorous components, and has a saturation adsorption capacity. They discovered that after the adsorption capacity was lost, ozone introduced for regeneration quickly restored the adsorption capacity even in the low temperature range of 20°C or less, leading to the completion of the present invention.

That is, the present invention provides a method for decomposing and removing malodorous components by introducing ozone into a gas containing malodorous components, and the nRRh method is characterized in that an adsorption layer is installed in the gas flow path and ozone is introduced intermittently. In addition, as an embodiment, a suitable adsorbent installed in the adsorption layer is a binary oxide consisting of titanium and silicon, a binary oxide consisting of titanium and zirconium, and/or a binary oxide consisting of titanium, silicon, and zirconium. The A component is a ternary oxide consisting of manganese (Mn), iron (Fe), cobalt (CO), nickel (Ni), zinc (Zn), silver (Ag), and platinum (Pt).
), palladium (Pd), and rhodium (Rh), and the composition of the adsorbent is such that the A component is 40 to 40% by weight of the oxide. 100% by weight, B component is Mn,
Fe, Co.

Ni, Zn and A! It is characterized in that + is in the range of O to 60% by weight as an oxide, and Pt, Pd, and Rh are in the range of 0 to 10% by weight as metal elements.

<Function> The above-mentioned preferred adsorbent according to the present invention is characterized by a binary composite oxide (hereinafter referred to as Ti 02
-8i 02), a binary composite oxide consisting of titanium and zirconium (hereinafter referred to as = 9-Ti 02-Zr 02), and a ternary composite oxide consisting of titanium, silicon, and zirconium (hereinafter referred to as Ti
02-8i 02-Zr 02) is used as a catalyst component.

In general, binary composite oxides consisting of titanium and silicon are used, for example, by Kozo Tabe (Catalysts, Vol. 17, Nα3.72 p.
(1975), it is known as a solid acid, exhibits remarkable acidity that is not found in the constituent oxides alone, and has a high surface area.

In other words, Ti 02-8i 02 is not simply a mixture of titanium oxide and silicon oxide, but it can be recognized that titanium and silicon form a so-called binary oxide, resulting in its unique physical properties. It is. Furthermore, binary mixed oxides consisting of titanium and zirconium and ternary composite oxides consisting of titanium, zirconium and silicon are also specified as mixed oxides having properties similar to Ti 02-8i 02.

Furthermore, as a result of analysis by X-ray diffraction, the above composite oxide
It has an amorphous or almost amorphous microstructure.

In the deodorizing method of the present invention, the unique performance of the adsorbent, that is, the mechanism in which ozone decomposes and removes the adsorbed malodorous substances especially in a low temperature range and quickly recovers the adsorption performance is not certain, but the above-mentioned composite It is thought that the various properties of the oxide have a favorable effect on the adsorption of malodorous substances and the oxidation reaction between the adsorbed substances and ozone. It is believed that the addition of elements such as silver, platinum, palladium, and rhodium or their compounds acts more effectively and plays a role in accelerating the reaction between ozone and the adsorbed malodorous substances.

Adsorbent A component Ti 02-8i 02 , TiO
2-Zr 02 and Ti 02-8i○2-ZrO2
It is preferable that the surface area of each of these is 30 m2/g or more.

The composition of adsorbent A component is 20 TiO2 in terms of oxide.
~95 mol% SiO2 or ZrO2 or SiO
The sum of Ti 0 and ZrO2 is 5 to 80 mol% (Ti 0
2 +Zr 02 +Si 02 =100 mol %) gives preferable results.

The composition of the adsorbent according to the present invention is that component A is 40 to 100% by weight as an oxide, and component B is manganese (Mn).
), silver (A()), iron (Fe), cobalt (CO), zinc (ZO), and nickel (Ni) in weight percentages as oxides of 0 to 60%, platinum (Pt), palladium (Pd ) and 0 for rhodium (Rh)
It is preferably in the range of 10% by weight.

If the daily component is outside the above range, the regeneration of the adsorption capacity by ozone will be insufficient, and in the case of platinum, palladium, and rhodium, the raw material cost will be high and sufficient effects cannot be achieved.

To prepare TiO2-8i 02 used in the present invention, first, the titanium source must be selected from inorganic titanium compounds such as titanium chlorides and titanium sulfate, and organic titanium compounds such as titanium oxalate and tetraisopropyl titanate. The silicon source can be selected from inorganic silicon compounds such as colloidal silica, water glass, silicon tetrachloride, and major silicon compounds such as tetraethyl silicate. Some of these raw materials contain trace amounts of impurities and contaminants, but this does not pose a problem as long as it does not significantly affect the physical properties of the Ti 02-8i 02 obtained.

A preferred method for preparing Ti 02-8i 02 includes the following method.

(2) A method in which titanium tetrachloride is mixed with silica sol, ammonia is added to form a precipitate, the precipitate is washed, dried, and then calcined at 300 to 650°C.

■ Add sodium silicate aqueous solution to titanium tetrachloride,
The reaction was carried out to form a precipitate, which was washed and dried for 30 minutes.
A method of firing at 0 to 650°C.

■ Ethyl silicate [(02H50)4Si] is added to a water-alcohol solution of titanium tetrachloride to cause a hydrolysis reaction to form a precipitate, which is washed and dried for 300~
A method of firing at 650℃.

(2) A method in which ammonia is added to a water-alcohol solution of titanium oxide chloride (Ti OCj!2) and ethyl silicate to form a precipitate, which is washed, dried, and then calcined at 300 to 650°C.

Among the above preferred methods, method (2) is particularly preferred, and this method is specifically carried out as follows. That is, the titanium source and silicon source compounds are replaced by TiO
The molar ratio of 2 and SiO2 is set to a predetermined amount, and titanium and silicon are converted into oxides to have a concentration of 1 to 100 (] 71 in an acidic aqueous solution state or sol state).
Keep at 00℃. Animonia water was added dropwise as a neutralizing agent into the solution while stirring, and a coprecipitated compound consisting of titanium and silicon was formed for 10 minutes to 3 hours at 82 to 10 minutes, and after being filtered and thoroughly washed, T
i 02-8i 02 can be obtained.

Also, Ti 02-Zr 02-8i 02 Nitsui T
.

-14= is prepared by the same method as Ti 02-8i 02, and the zirconium source is zirconium chloride,
It can be selected from inorganic zirconium compounds such as zirconium sulfate and organic zirconium compounds such as acidophilic zirconium.

That is, by treating a zirconium compound together with a titanium compound in the same manner as in the above method, Ti02-ZrO2
-8i 02 can be easily prepared. And the abundance of this zirconium is Ti 02 + Zr○
It is preferable that the amount of ZrO2 is up to 30% by weight based on the total ffl of 2+Si02. Ti
02-Zr 02 can be prepared in the same manner.

TiO2-8i 02, Ti prepared by the above method
02-Zr 02 and Ti 02-8i 02-Zr
Using O2, the finished adsorbent is obtained by the method shown below. - For example, Ti 02-3io2 powder is added together with a molding aid, mixed and kneaded while adding an appropriate amount of water, and molded into a pellet or honeycomb shape using an extrusion molding machine.

After drying the molded product at 50 to 120°C, dry it at 300 to 800°C, preferably 350 to 600°C, for 1 to 10 hours, preferably 2 hours.
The adsorbent can be obtained by calcination under air flow for ~6 hours.

In addition, when manganese, iron, nickel, cobalt, zinc, silver, platinum, palladium, and rhodium are added to Ti 02-8i 02 to make it into an adsorbent, an aqueous solution of the above metal salt is
i 02-8i 02 After impregnating and supporting the molded body,
It can be made into an adsorbent by drying and firing.

On the other hand, as an alternative method, an aqueous solution of the metal salt described above may be added to the Ti 02-8i 02 powder together with a molding aid, and the mixture may be kneaded and molded.

The shape is not limited to the above-mentioned pellet shape and honeycomb shape, but may be suitably selected from columnar, cylindrical, plate, ribbon, corrugated, pipe, donut, lattice, and other integrally molded shapes.

Next, starting materials for component B used together with component A in the adsorbent include oxides, hydroxides, inorganic acid salts, organic acid salts, etc., especially ammonium salts, oxalates, nitrates, sulfates, and halogen salts. Appropriately selected from compounds, etc.

The deodorizing method according to the present invention is applicable to the treatment of gases emitted from food storage, garbage storage, human waste treatment plants, sewage treatment plants, garbage incineration plants, cleaning factories, printing factories, paint factories, general chemical factories, etc. Can be used.

Malodorous components include hydrogen sulfide, methyl sulfide, methyl mercaptan, methyl disulfide, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, isobutylamine, pyridine, acetone, methyl ethyl ketone, butyric acid, acetaldehyde, acrolein, phenol, Examples include benzene, xylene, toluene, butenes, etc., and substantially all of these substances can be deodorized and removed by the method of the present invention.

Further, in the deodorizing method of the present invention, malodorous components in the gas are first adsorbed and collected by the adsorbent having the above-mentioned adsorption capacity, and the gas is deodorized and adsorption with reduced adsorption capacity is performed intermittently on the adhesive. This method maintains the deodorizing effect over a long period of time by repeating the process of introducing ozone to decompose the adsorbed material and regenerating it. By introducing ozone into the circulating gas without stopping the processing gas flow,
It can be regenerated, and the malodorous components in the gas to be treated and the substances adsorbed on the adsorbent can be simultaneously decomposed and removed. Therefore, as in the conventional adsorption deodorization method, for the adsorption and desorption regeneration process,
There is no need to install two adsorbent layers and use them alternately, and adsorption and regeneration can be performed using just the tower.

Adsorption and regeneration conditions are appropriately selected depending on the components and concentration of the gas to be treated, and these conditions can be determined by simple tests. For example, the space velocity for the adsorbent is set in the range of 100 to 1000 Hr-1, and the ozone concentration introduced during regeneration is preferably in the range of 1 to iooppm. Outside this range, if the concentration is low, the regeneration efficiency is poor, and if the concentration is high, the ozone concentration is preferably in the range of 1 to iooppm. Although regeneration can be carried out in a short time, unreacted ozone is emitted and may cause secondary pollution.

In addition, the interval and duration of intermittent introduction of ozone are approximately once every 1 to 24 hours for 30 minutes to
It is preferable to design within a range of 12 hours.

The method of introducing ozone intermittently can be easily set by programming in advance and combining an ozone generator and a timer.

The present invention will be explained in more detail below using Examples, but the present invention is not limited to these Examples.

Example 1 A composite oxide consisting of titanium and silicon was prepared by the method described below. As a titanium source, an aqueous solution of titanyl sulfate having the following composition was used.

Ti 0804 (Ti 02 exchange g) 250MJl
Total H2S 04 1100 (+/ 1 separately water 4001 and ammonia water (NH3, 25%) 2801
was added to this, and Snowtex-NC8-30 (silica sol manufactured by Yasan Kagaku, containing approximately 30% by weight as SiO2) was added.
24Kg was added. Into the obtained solution, add 153) of the above sulfuric acid aqueous solution of titanyl sulfate to 300j of water! A titanium-containing sulfuric acid aqueous solution diluted by adding the titanium sulfuric acid solution was added dropwise to the stirring vessel to form a coprecipitated gel. Further, it was left as it was for 15 hours.

The thus obtained Ti 02-8t 02 gel was filtered,
After washing with water, it was dried at 200° C. for 10 Fff.

Then, it was fired at 550° C. for 6 hours in an air atmosphere. The composition of the obtained powder is Ti 02 :Si 02 =4=1
(molar ratio), the BE'T surface area was 185TrL2/g. The powder thus obtained was hereinafter referred to as TS-1, and using this powder, a lattice honeycomb adsorbent was prepared by the method described below.

Add an appropriate amount of water to 10 kg of the above TS-1 powder, mix well with a kneader, thoroughly knead with a kneader, and extrude the homogeneous mixture into an extrusion molding machine with external dimensions of 50# in length, 50# in width, and length. 100# lattice honeycomb (thickness 0.3m 1 opening 1.
4#III+), dried at 150°C-20= for 5 hours, and then calcined at 300°C for 2 hours in an air atmosphere to obtain an adsorbent named TS-18.

The lattice-like honeycomb adsorbent obtained in the above procedure was filled into a Pyrex tube so that the gas would not pass through the tube, and 2.5 Nm/Hr of air containing 5 ppm of trimethylamine, a typical malodorous substance, was heated at 25°C. After 10 hours of continuous introduction into the adsorbent layer placed under these conditions, the gas at the outlet of the adsorbent layer was analyzed to measure the trimethylamine concentration.

After that, the gas flow continued, and ozone introduction was started when the adsorption capacity of the adsorbent was exceeded and the concentration of malodorous components at the outlet of the adsorbent layer reached the same level as the concentration at the inlet. The ozone introduced was adjusted to have a concentration of 30111) III in the gas, and the introduction time was 5 hours. Before the end of ozone introduction, gas analysis at the outlet of the adsorbent layer was performed to measure the concentrations of ozone and trimethylamine. Thereafter, only the introduction of ozone was stopped, and the introduction of the malodorous component-containing gas was continued, and after 10 hours of regeneration, the gas at the outlet of the adsorbent layer was analyzed. Thereafter, the operation of intermittently introducing ozone into the adsorbent layer where the adsorption had broken through was repeated 10 times in the same manner as described above, and the gas at the outlet of the adsorbent layer was analyzed after 1°-21= hours.

The equipment used for gas analysis was F for trimethylamine.
Ozone was measured using gas chromatography with ID and an ozone monitor. The results obtained are shown in Table-1.

Example 2 Using the adsorbent obtained in Example 1, the temperature of the adsorbent layer was set to 0.
The same operation as in Example 1 was performed except that the temperature was maintained at °C.

The results obtained are shown in Table-2.

Example 3 Ti 02-Zr 02 was prepared by the method described below.

Zirconium oxychloride [Zr QC
12.8H20Co19.3 K'J was dissolved in a sulfuric acid aqueous solution 7 of titanyl sulfate having the same composition as used in Example 1.
Mix well while adding 81. While maintaining the temperature at about 30° C. and stirring well, aqueous ammonia was gradually added dropwise to the mixture until l) H reached 7, and the mixture was left to stand still for 15 hours.

The thus obtained Ti 02-Zr 02 gel was filtered, washed with water, and then dried at 200° C. for 10 hours. Then, it was fired at 550° C. for 6 hours in an air atmosphere. The composition of the obtained powder was Ti 02 :Zr 02 =4:1 (molar ratio)
and the SET surface area was 140TrL/q.

The powder obtained here is hereinafter referred to as TZ-1.

TZ-1 according to the method described in Example 1 using TZ-1
11-(An adsorbent was prepared.

Using the obtained adsorbent, adsorption and regeneration effects were measured in the same manner as described in Example 1. Table of results obtained.
Display on 1.

Example 4 Using the adsorbent obtained in Actual Flow Example 2, the adsorption and regeneration effects were measured in the same manner as in Example 2. The results obtained are shown in Table-2.

Example 5 Ti 02-8i02- according to the method of Examples 1 and 2
Zr 02 was prepared. The composition of the obtained powder is TiO2
:5i02 :Zr02=80:16:4 (molar ratio), and the SET surface area was 180 m 2 /+1. The powder obtained here is hereinafter referred to as TSZ-1.

Using TSZ-1, T was prepared according to the method described in Example 1.
An adsorbent named SZ-1H was prepared.

Using the obtained adsorbent, adsorption and regeneration effects were measured in the same manner as in Example 1. Table 1 shows the results obtained.
to be displayed.

Example 6 Using the adsorbent obtained in Example 5, the adsorption and regeneration effects were measured in the same manner as in Example 2. The results obtained are shown in Table-2.

= 24 - 25 - Example 7 -TS-1) 1 of Example 1 A lattice honeycomb was impregnated with an aqueous manganese nitrate solution, dried and fired to form an oxide, and the weight ratio was TS-1:Mn○2 = 90 :1 o of adsorbent was obtained. Using this, adsorption and regeneration effects were measured. The method was the same as that described in Example 2 except that the introduced ozone concentration was 20+11)Ill and the introduction time was 2 hours. The results obtained are shown in Table-3.

Example 8 Using the adsorbent obtained in Example 7, adsorption and regeneration effects were measured. The method was the same as that described in Example 7 except that the adsorbent layer temperature was set at 25°C. The results obtained are shown in Table-4.

Examples 9 to 15 Adsorbents were prepared according to Example 7 by changing the B component added to the adsorbent A component.

Nitrate of iron, cobalt, nickel, silver and platinum, chloride of palladium and rhodium were used as raw materials for the day.

Using the adsorbent thus obtained, adsorption and regeneration effects were measured by the method described in Example 7.

The adsorbent composition and the results obtained are shown in Table-3.

Examples 16-22 Using the adsorbents obtained in Examples 9-15, adsorption and regeneration effects were measured by the method described in Example 8. The adsorbent composition and the results obtained are shown in Table-4.

Comparative Examples 1-2 An adsorbent was prepared according to Example 7 except that a lattice honeycomb of activated alumina and activated carbon was used instead of TS-IH.

Using the adsorbent thus obtained, adsorption and regeneration effects were measured by the method described in Example 8.

The adsorbent composition and the results obtained are shown in Table-4.

Claims (2)

[Claims] (1) A deodorizing method in which ozone is introduced into a gas containing malodorous components to decompose and remove the malodorous components, the method comprising installing an adsorption layer in the gas flow path and introducing ozone intermittently. (2) Binary oxide consisting of titanium and silicon, binary oxide consisting of titanium and zirconium, and/or ternary oxide consisting of titanium, silicon and zirconium as the adsorbent installed in the adsorption layer as component A. and manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), silver (Ag), and platinum (Pt).
), palladium (Pd), and rhodium (Rh) as a component B, the composition of the adsorbent is such that the component A is 40 to 40% by weight of the oxide. 100%, B components are Mn, Fe, Co
, Ni, Zn, and Ag are in the range of 0 to 60% by weight as oxides, and Pt, Pd, and Rh are in the range of 0 to 2% by weight as metal elements. Deodorizing method described in section.