JPS6034891B2 - Dry deodorization equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to a dry deodorizing device.

More specifically, after pre-treating and removing hydrogen sulfide with an iodide impregnator, ozone is added, and the ozone and bromine oxidize and remove the malodorous components in the gas to be treated, and the odor is emitted together with the air to be treated. This invention relates to a dry deodorizing device that uses an oxidizing agent to remove bromine and ozone. Conventionally, as a dry deodorizing apparatus of this type, there has been an adsorption deodorizing apparatus using activated carbon as shown in FIG.

In the figure, 1 is a blower, 2 is an adsorption tower, and 3 is an activated carbon layer filled in the adsorption tower 2. The foul-smelling air A to be treated is sent to the adsorption tower 2 by a blower, and is passed through the activated carbon layer 3.
During aeration, malodorous components are adsorbed and removed mainly by physical adsorption, and some by chemical adsorption with metal components present as impurities (ash) in the activated carbon, and are released as treated air B. In such devices, the deodorizing performance depends on the physical adsorption capacity of activated carbon. In order to slowly remove components that are small in amount and have long adsorption zones, sufficient deodorizing performance cannot be obtained unless a large amount of activated carbon is filled, so it has often been difficult to put it into practical use economically. Also, JP-A-50-1306
As disclosed in Publication No. 7y, there is a deodorizing method in which hydrogen sulfide and mercaptans are removed using impregnated carbon in which bromine or bromine compounds are supported on activated carbon, but ozone is added to the gas to be treated. A method in which oxidation removal is used in combination to increase the removal ability has the disadvantage that ozone and bromine remaining with the gas to be treated tend to leak out when the concentration of hydrogen sulfide in the gas to be treated is high.

This invention was made in order to eliminate the drawbacks of the above-mentioned activated carbon adsorption method and deodorization method using activated carbon carrying bromine or bromine compounds. Acidic malodorous components such as hydrogen sulfide and methyl mercaptan are removed through a packed bed of impregnates (hereinafter abbreviated as 12 impregnates) in which urides are impregnated onto carriers such as activated carbon, activated clay, silica, alumina, alumina, etc.

Next, ozone is added to this treated gas, and then hydrogen bromide or hydrobromic acid is brought into contact with an impregnator (hereinafter abbreviated as HBG impregnator) which is impregnated on a carrier such as activated carbon, activated clay, silica, alumina, alumina, etc. and oxidizes and decomposes malodorous components.
Furthermore, this treated air is passed through an activated carbon layer or an alkali impregnator layer to remove excess ozone and bromine contained in the air. FIG. 2 is a flowchart of an embodiment of the present invention, in which 4 is a desulfurization tower, 5 is 12 impregnated packed beds (for example, filled with KI-impregnated activated carbon), 6 is a compressor, 7 is an ozonizer, 8 is a diffuser pipe, 9 10 is a deodorizing tower, and 10 is a HBn-impregnated bed (for example, filled with HBh-impregnated activated carbon).
It is.

Next, the operation will be explained. The air A to be treated sucked by the proa 1 comes into contact with KI-impregnated activated carbon in the sulfuric acid tower 4, and acid gases such as hydrogen sulfide and methyl mercaptan are removed by adsorption or reaction. KI of approximately 1% in terms of
SV30 air using impregnated activated carbon that is impregnated with activated carbon
After continuous aeration for 40 hours at 00/hr, the pH of the impregnated carbon was examined using the granular activated carbon test method (JIS-1474), and the pH increased from 9.6 to 10.2.

This is presumed to be because iodine (hereinafter abbreviated as 12) and potassium hydroxide are produced according to reaction formula m, and acidic components such as hydrogen sulfide and methyl mercaptan interact with these products according to reaction formula ■, (3}, '4} is considered to be removed. 2KI 102 10 days 20 → 2KOH 112 11
/202... mH2S+KOH→KHS+日20...■日2S+12→2
HI+S...{3-C
H3SH+12 → CH31 ten HI+S
(4) Ozonized air is added to the gas from which most of the hydrogen sulfide and methyl mercaptan have been removed through the aeration pipe 8, mixed while passing through the blower, and introduced into the deodorizing tower 9.

In the deodorizing tower 9, the water first passes through an HBr-impregnated bed 10. In this process, the reaction formula {Immediately, therefore, malodorous components are catalytically oxidized on the surface of the impregnator by bromine (hereinafter abbreviated as Br2) generated by the rapid reaction between ozone and HBr, and an oxidation reaction also occurs in the gas phase. The malodorous components are removed by oxidation. Koden r+03 → Br2 Toka 2
0102 ... The treated air that has passed through the HBr impregnated body packed bed 10 has ozone and Br2 remaining in the air adsorbed in the activated carbon packed bed 3.
Ozone is reduced to oxygen.

The treated air from which malodorous components and secondary pollution sources such as oxidizing agents have been removed is discharged as clean air B to the outside of the system. Although the outline of the structure of this invention is as above, the reaction with malodorous components and effects will be explained in detail below.

This deodorizing device is particularly effective against foul-smelling air with a high concentration of hydrogen sulfide.

When ozone-added foul-smelling gas is passed through the impregnated coal carrying HBr, hydrogen sulfide is oxidized and sulfuric acid is produced on the surface of the impregnated coal, which drives out HBr and performs displacement adsorption, reducing the amount of HBn impregnated. Low addition, Br2 according to the reaction formula ■
deodorizing performance decreases because the production reaction is suppressed. This tendency is remarkable when the hydrogen sulfide concentration is high. Figure 3 shows the odor of a trickling filter used to treat domestic wastewater.
The graph shows the change in the layer thickness of the bromine impregnation rate of the used HBr-impregnated carbon when deodorizing treatment is performed over the entire length.

The experiment used two reaction tubes with a diameter of 400, one filled with 15 cm of HBr-impregnated carbon of 4 to 8 mesh, and the other filled with 5 cm of KI-impregnated carbon of the same particle size. After providing space for ozone addition, add 1 HBr-impregnated coal.
The test was carried out with 0 cm filling. The aeration rate of the processing gas is 10 each.
These are the results when ozone was added to the inlet side of each HBr-impregnated coal filling part at 3 ppm after diluting the treatment gas. In the figure, characteristic curve A is when ozone is added and the air is passed through a HBc-impregnated coal layer through KI-impregnated coal, and characteristic curve B is when ozone-added foul-smelling air is passed through a packed bed containing only HBr-impregnated coal. Figure 2 shows the change in layer thickness of bromine impregnation rate. The bromine impregnation rate of the HBr-impregnated carbon used was 0.8% by weight. When hydrogen sulfide is removed through KI-impregnated coal, the bromine impregnation rate remains relatively high at 0.6-0.65%, but if the KI-impregnated coal is not passed through in advance, bromine impregnation is The bromine impregnation rate decreased significantly to .25 to 0.3%. In addition, when the pH of the HBr-impregnated coal up to the 2nd skin of the gas inlet to be treated is investigated using the method of JISK1474, it is found that K
When passed through I-impregnated carbon, the pH is 2.1, and when there is no KI-impregnated carbon, the pH is 1.4, which is strongly acidic, and the sulfate group is 5.6.
%was detected. The pH of the adjusted HBr-impregnated coal was 2.4.
Therefore, it is considered that when the KI-impregnated coal was not passed through, the accumulation of sulfate radicals was significant, which caused a significant decrease in the pH of the HBr-impregnated coal. Also, the deodorizing performance is better when KI-impregnated coal is combined, and in this case, hydrogen sulfide is not absorbed (less than 5% of the inlet concentration), but the air to be treated with ozone added is not absorbed. When the packed bed containing only HBr-impregnated coal was aerated, complete breakthrough occurred. Therefore, when treating malodorous gas with a high concentration of hydrogen sulfide, adding ozone and aerating the HBr-impregnated coal after removing hydrogen sulfide in pretreatment will suppress the accumulation of sulfuric acid and suppress the replacement of HBr with sulfuric acid. The rate of decrease in bromine impregnation rate is slow,
It is thought that the deodorizing ability can be maintained for a long time. The KI-impregnated coal described in this example was prepared by soaking crushed charcoal in a 4% potassium chloride aqueous solution for 30 minutes and drying it with nitrogen gas.

The amount of iodine impregnated was 0.9% as a 12 equivalent value. 2
If a KI aqueous solution of 0% or more is used, the chemical cost will be 5 times higher than that of impregnated carbon.
If it exceeds 0%, it becomes an economic problem, so the adhesion rate should be 0.
5-5% is good.

The amount of impregnation was determined by a titration method using mercuric nitrate method after soaking KI-impregnated coal in hot water and extracting iodine. Although KI-impregnated carbon has been described here, the same effect can be achieved if it is an alkali metal or alkali metal iodide.

In addition to activated carbon, the carrier may also be activated clay, silica, alumina, or alumina. Furthermore, although this example shows the case where activated carbon is used as a surplus oxidizing agent decomposer, alkalis such as sodium hydroxide, potassium hydroxide, sodium hydroxide, potassium carbonate, etc. A similar effect can be obtained by using an alkali or an impregnated body impregnated on a carrier such as the like, and chemical adsorption of the product sulfur dioxide gas is also possible.

As described in detail above, this invention removes acidic components such as hydrogen sulfide and methyl mercaptan through 12 impregnant packed layers, and then adds ozone and passes through an HBr impregnant layer.
Furthermore, it is configured to pass through an oxidizing agent decomposer layer such as an activated carbon layer before being discharged to the outside of the system, which prevents sulfuric acid from accumulating in the HBr impregnator layer and also prevents the impregnated HBr from escaping. Therefore, Br2 produced by the reaction between ozone and HBr can be used effectively, and components such as ammonia, methyl sulfide, and methyl disulfide, which are difficult to remove by adsorption with activated carbon, can be efficiently removed. In addition, the activated carbon adsorbs and removes residual ozone and gas phase bromine in the treated air from which malodorous components have been oxidized, eliminating the risk of secondary pollution, which has great practical effects.

[Brief explanation of drawings]

Fig. 1 is a flow diagram of a conventional dry deodorizing device using activated carbon, Fig. 2 is a flow diagram showing an embodiment of the present invention, and Fig. 3 is a flow diagram showing an embodiment of the present invention.
The figure is a characteristic diagram showing changes in layer thickness of bromine impregnation rate in HBr-impregnated coal with and without pretreatment of acidic gas such as hydrogen sulfide with KI-impregnated coal. In the figure, 1 is a blower, 3 is a packed bed of activated carbon, 05 is a packed bed of 12 impregnated bodies, 7 is an ozonizer, and 10 is a packed bed of HBr impregnated bodies. Note that the same numbers in the figures indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A packed layer of an impregnating body for impregnating an iodide of an alkali metal or alkaline earth metal onto a carrier, an ozonizer, and an ozonized gas fed from the ozonizer. a device for dispersing air into the air to be treated containing malodorous components that has passed through the air, a packed bed of an impregnating body for impregnating hydrogen bromide or hydrobromic acid to a carrier, and a packed bed of a surplus oxidizing agent decomposer;
A dry deodorizing device comprising: an air supply device that allows the gas to be processed to pass through in the above order. 2. The dry deodorizing device according to claim 1, wherein the carrier of each impregnated body is activated carbon, activated clay, silica, alumina, or alumina. 3. A patent claim in which the surplus oxidizing agent decomposer is activated carbon or an alkali-impregnated body impregnated with an alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc. using activated carbon, activated clay, silica, alumina, or alumina as a carrier. A dry deodorizing device according to scope 1. 4 The amount of alkali metal or alkaline earth metal iodide impregnated on the carrier is 0.1 to 10% by weight in terms of iodine.
, preferably within the range of 0.5 to 5% by weight. 5 The amount of hydrogen bromide or hydrobromic acid impregnated on the carrier is 0.1 to 10% by weight, preferably 0.5 to 5% by weight in terms of bromine.
The dry deodorizing device according to claim 1, wherein the amount is within the range of % by weight.