JPH0144340B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a method for deodorizing malodorous gas, and more particularly to a method for improving the deodorizing method by cleaning malodorous gas. ``Conventional technology'' Traditionally, the following three methods have been used to deodorize malodorous gases generated in human waste treatment plants, sewage treatment plants, etc.: (1) Adsorption method (2) Cleaning method (3) Cleaning method + adsorption method law is used. In the above method, all malodorous gases are
Types: Acidic gases: hydrogen sulfide, sulfur compounds such as methyl mercaptan, lower fatty acids such as acetic acid and propionic acid Basic gases: ammonia, trimethylamine, etc. Neutral gases: methyl sulfide, methyl disulfide, etc. For example, deodorizing towers are installed for each category as shown below.

[Table] If the above methods are appropriately selected and combined depending on the mixture composition ratio and concentration of the target malodorous gas, it is possible to obtain a sufficiently satisfactory deodorizing effect. "Problems to be Solved by the Invention" However, conventional deodorizing towers require at least two towers (one for acidic gas, one for alkaline gas, etc.), and in many cases, as many as four to five towers are required. As far as equipment costs were concerned, they were by no means satisfactory. The present invention has been made by focusing on these conventional problems, and aims to provide a deodorizing method that greatly reduces the number of deodorizing towers compared to the conventional method and improves the removal rate of malodorous gases. It is said that "Means for Solving the Problems" In order to solve the above-mentioned technical problems, the present invention provides a deodorizing method using a cleaning method, which comprises irradiating a gas-liquid contact portion with ultraviolet rays. In the present invention, when the gas-liquid contact area (filler layer) is irradiated with ultraviolet rays, both the malodorous gas and the cleaning chemical are excited, and the cleaning effect is greatly improved. As the cleaning solution of the present invention, conventionally used acids and alkalis or oxidizing agents can be used, but oxidizing agents such as sodium hypochlorite or hydrogen peroxide are particularly convenient because they can be used regardless of the nature of the malodorous gas. It is. The ultraviolet rays are irradiated at the area where the cleaning liquid and the foul-smelling gas come into contact (the filler layer), and the ultraviolet irradiation lamp can be placed at any position. That is, it can be placed, for example, vertically through the filler layer in a vertical cleaning mode, or on the side of the filler layer in a horizontal cleaning mode. ``Operation'' When light is irradiated onto a substance, it is absorbed, and this absorbed light excites the electrons in the molecule, and the resulting excitation energy is transferred to other molecules or converted into its own vibrational energy. As a result, even at room temperature, the molecule is in the same state as if it had been heated to a high temperature, and bonds within the molecule are cleaved. In the present invention, irradiating the gas-liquid contact area with ultraviolet rays brings about the above-mentioned effects on both the malodorous gas and the cleaning chemical, and as a result, it is thought that the cleaning effect will be greatly improved. The present invention will be explained below based on examples. Example 1 A commercially available plastic filler 1 was prepared with a layer height of 100 cm.
A vertical packed tower packed to a diameter of 20cm is filled from the top.
Add 500ppm of sodium hypochlorite or hydrogen peroxide 2 from nozzle 3, and the circulation amount of liquid 2 is 50ppm.
ml/min. Then, from the lower inlet 4 of the tower, a malodorous gas having the following composition is introduced at a flow rate of 40/min (air linear flow velocity 0.02 m/sec, cleaning chemical amount/gas ratio 1.25).
ml/) and is irradiated with ultraviolet light from a 100W ultraviolet lamp 5 installed vertically inside the packed tower as shown in Figure 1, the composition of the foul-smelling gas at the outlet 6 at the top of the packed tower is as shown in Table 1. Ta. There is a significant difference in removal rate compared to the conventional method that does not involve UV irradiation.
In addition, 7 is a circulation pump.

[Table] Example 2 Using the same packed tower as in Example 1, a deodorization test was conducted under the same conditions as in Example 1, such as the flow rate of malodorous gas, the amount of cleaning fluid circulated, and the ultraviolet lamp, while changing the type of malodorous gas and cleaning fluid. . Caustic soda and hydrochloric acid are used as cleaning solutions to remove the foul-smelling gases shown in Table 2.
A comparison was made with a conventional method that does not involve ultraviolet irradiation, and the results are summarized in Table 2.

[Table] As is clear from the table above, there is a significant difference in deodorizing efficiency compared to the conventional method that does not use ultraviolet irradiation. "Effects of the Invention" Compared to conventional deodorizing methods, the present invention, which uses ultraviolet irradiation, shows a significant difference in the removal rate of malodorous gases, as is clear from the above examples, and the expected malodor removal efficiency. I was able to improve it significantly. In addition, in conventional deodorization methods, the inlet gas concentration is several tens of ppm.
In the following cases, one deodorizing tower each for acidic gas and basic gas is required, and the inlet gas concentration is several tens of thousands.
If the amount exceeds ppm, two stages (two units) are required for the deodorizing tower for acidic gases alone. However, if the present invention is used, if the inlet gas concentration is relatively low, such as several tens of ppm or less, an oxidizing agent such as sodium hypochlorite or hydrogen peroxide can be used as the cleaning solution, and one deodorizing tower is sufficient. It is. Further, even when the inlet gas concentration is relatively high, such as several tens of ppm or more, one stage (one unit) of the deodorizing tower for acidic gas is sufficient, as shown in Table 3.

[Table] As a result, the construction cost, maintenance cost, and installation space of the deodorizing device can be significantly reduced compared to conventional methods, and these effects will make a significant contribution to this field.

[Brief explanation of drawings]

The accompanying drawing is a mechanical side view of a vertical deodorizing tower showing an example of carrying out the present invention. 1... Filler, 2... Cleaning liquid, 3... Nozzle,
4... Bottom entrance of the tower, 5... Ultraviolet lamp, 6...
... Upper outlet of the tower, 7... Circulation pump.

Claims (1)

[Claims] 1. A method for deodorizing foul-smelling gases generated in human waste treatment plants, sewage treatment plants, etc., which is a method for deodorizing a cleaning method using an oxidizing agent, acid, or alkali as a cleaning liquid, and is characterized by irradiating the gas-liquid contact area with ultraviolet rays.