JPH01315317A - Deodorizing device for gas - Google Patents

Abstract

PURPOSE:To eliminate clogging of packed beds of a gas deodorizing device by constituting the device of a lower stage packed bed section for deodorization by a physicochemical method and an upper stage packed bed section for deodorization by a biological method by spraying washing water, and regulating grain size of the carrier in the lower stage deodorizing section to a larger grain size than that in the upper deodorizing section. CONSTITUTION:A packed bed 15 packed with many carriers comprising ceramic granules, etc.,is formed to a two-layered structure, and carriers having larger grain size than carriers in the upper stage packed bed 15b are packed in the lower stage packed bed 15a, and carriers having an intermediate grain size are packed in the upper stage packed bed 15b. Washing water from a water spray nozzle pipe 16 washes off decomposed product of malodorous components produced by the effect of microorganisms sticking to the surface of the carriers in the packed bed 15b, and becomes acidic. Gas 10 to be treated from an opening port 13 is allowed to contact with the acidic washing water in the packed bed 15a and neutralizes and removes basic malodorous components in the gas 10. Then, residual malodorous components are decomposed by microorganisms in the packed bed 15b a discharged from a discharging port 14. Since the grain size of the carrier in the lower stage packed bed is larger than that in the upper packed bed, clogging of the packed bed 15a due to sludge generated in the packed bed 15b is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a gas deodorizing device that combines a biological treatment method using microorganisms and a physicochemical treatment method using chemical cleaning.
It can be used to deodorize exhaust gas generated in all fields such as livestock farming, feed and fertilizer manufacturing plants, chemical plants, and sewage treatment plants.

[Prior art] Methods for removing malodorous components contained in the gas phase include physicochemical methods such as combustion methods, chemical cleaning methods, and adsorption methods, and biological methods such as soil deodorization methods and activated sludge methods. However, in recent years, biological methods that do not cause secondary pollution, can simultaneously process a variety of gases, and have low processing costs have been attracting attention.

An example of the biological method will be explained with reference to FIG. 2. In the figure, 1 is a deodorizing tower, inside which there is a packed bed 2 in which packing materials (carriers) (not shown) are laminated, and the Microorganisms are attached to the surface. 3 is a water spray nozzle pipe for periodically spraying water on the packed bed 2 to clean it. Reference numeral 4 denotes a washing water tank provided at the bottom of the deodorizing tower 1, in which water falling through the packed bed 2 is stored and circulated. Reference numeral 5 denotes an alkaline agent tank for supplying an alkaline agent to the cleaning water tank 4 through a supply pipe 6 when necessary, and the pH value of the cleaning water is kept within a range that maintains the activity of microorganisms (usually pH 6 to 6).
8). Reference numeral 7 denotes a make-up water supply pipe for adjusting the salt concentration of the washing water to an extent that does not inhibit the activity of microorganisms. In the figure, 8 is a discharge water pipe.

Next, its operation will be explained.

The gas to be treated 10 is fed from the lower part of the deodorizing tower 1, and while rising and passing through the packed bed 2, it is brought into contact with microorganisms attached to the surface of the packed material, and the malodorous components contained in the gas to be treated 10 are removed by the microorganisms. Disassemble. The products generated as a result of this decomposition are washed away from the surface of the packing by periodically sprinkling cleaning water onto the packing bed 2 from the water spray nozzle pipe 3, and
Watering provides hydration to microorganisms. In this case, the cleaning water falls through the packed bed 2 and is stored in the cleaning water tank 4 below and is used for circulation.As the cleaning water is used repeatedly, the pH value of the cleaning water gradually decreases and the microorganisms become active. inhibit. Therefore, in order to prevent this, for example, caustic soda is added to the alkaline agent tank 5 as an alkaline agent r.
Supply water from time to time to neutralize the wash water. In addition, the salt concentration in the wash water increases due to the supply of caustic soda, which inhibits the activity of microorganisms. Therefore, in order to maintain the salt concentration below a predetermined level, a portion of the wash water is discharged through the discharge water pipe 8, and a make-up water wave is Replenish fresh water from supply pipe 7.

By passing the gas to be treated 10 through the packed bed 2, the malodorous components contained therein are removed as described above, and the odorless gas 10a is released into the atmosphere from the upper part of the deodorizing tower 1.

[Problems to be Solved by the Invention] The conventional deodorizing device for malodorous gas attaches microorganisms to the surface of the filling layered in the filling layer 2 as described above, and brings the microorganisms into contact with the gas to be treated 10. As a result, the malodorous components contained are decomposed by microorganisms.
The degree of freedom in using microorganisms will increase. In other words, microorganisms that have the property of decomposing malodorous components develop and proliferate, regardless of whether the malodorous components are sulfur-based such as hydrogen sulfide or nitrogen-containing substances such as ammonia. Therefore, microbiological deodorization particularly contributes significantly to lower processing costs. However, the conventional device still has the following problems.

(1) When it is necessary to remove a large amount of malodorous components, there is a limit to the decomposition rate of malodorous components by microorganisms, so the deodorizing equipment becomes large and complex, creating difficult problems in terms of securing land, etc. Therefore, the usage is also likely to be restricted.

(2) When the concentration of malodorous components increases, the activity of microorganisms is inhibited, so when removing high-concentration malodors, it is necessary to install other deodorizing equipment, which increases the size and complexity. If the concentration of the malodorous component varies greatly, the decomposition rate of the malodorous component by microorganisms will be slow to follow, making it necessary to install another deodorizing device, resulting in the same problem as in (2) above.

(3) Along with (1) and (2) above, it reduces the advantage of low processing costs, which is a feature of biological treatment methods.

(4) The sludge generated when malodorous components are decomposed by microorganisms tends to clog the packed bed.

The present invention has been made in order to solve the problems of the conventional methods as described above, and provides a deodorizing device that has a small and simple configuration and can deodorize gas with high efficiency and eliminates clogging of the packed bed. The purpose is to

[Means for Solving the Problems] A gas deodorizing device according to the present invention includes a packed bed in a deodorizing tower, a lower packed bed portion located below and having a function of removing malodorous components by a physicochemical method, and The upper packed layer is located above the packed bed and is sprayed with washing water, and has the function of removing malodorous components using a biological method. The lower filled layer portion is made larger than the filled layer portion of the lower layer.

[Function] In the present invention, a lower packed bed section having the function of removing malodorous components by a physicochemical method located below the packed bed of the deodorizing tower and a biological method located above the packed bed section are provided. Since the deodorizing tower is formed with an upper packed bed section that has the function of removing malodorous components, the gas to be treated that is introduced into the lower part of the deodorizing tower passes through the lower and upper packed bed sections in order and is released into the atmosphere. First, the malodorous components in the gas are decomposed by microorganisms in the upper packed bed section. Next, when the upper packed bed is washed with washing water, this washing water contains the acid generated in the upper packed bed, and the acidic washing water is used to wash the lower packed bed. Ru. In the lower packed bed section, the acidic cleaning water and the gas to be treated come into gas-liquid contact, so that ammonia, methylamine,
Basic malodorous components such as dimethylamine and trimethylamine are neutralized and removed, and the acidic cleaning water becomes neutral and falls into the cleaning tank.

In this way, most of the basic malodorous components in the gas to be treated are neutralized and removed in the lower packed bed, so the gas to be treated with less load and less load fluctuation is transferred to the upper packed bed. will be sent. Therefore, the load on the upper packed bed is reduced both quantitatively and qualitatively, so the malodorous components remaining in the gas to be treated are quickly removed without inhibiting the activity and followability of microorganisms in the upper packed bed. It can be disassembled and processed.

In addition, since the grain size of the carrier in these packed bed parts is gradually increased from the upper packed bed part to the lower packed bed part, the void ratio, that is, the cross-sectional area of the gap increases, and the upper part of the packed bed becomes larger. Clogging of the lower packed bed section due to sludge generated when malodorous components are decomposed by microorganisms in the bed section is also reduced.

[Example] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments shown in the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

In the figure, 11 is a cylindrical deodorizing tower, and a washing water tank 12 is provided at the bottom. L2a is a stirring tank attached to the washing water tank 12. Reference numeral 13 is an inlet for the gas to be treated IO which opens into the cleaning water tank 12, and reference numeral 14 is an outlet for the treated gas provided at the top of the deodorizing tower 11. Reference numeral 15 denotes a filling layer filled with a large number of ceramic particles (hereinafter referred to as carriers), for example. This filling layer 15 is formed into a two-layer structure having lower and upper filling layer portions 15a and 15b.

The particle size is 20 to 30+af in the lower packed bed part 15a.
A large particle size carrier having a specific surface area of 100rtf/n+3 or more and a void ratio of 70% or more is filled so that the particle diameter is about 10 mm to 20 mm in the upper packed layer section 15b.
A specific surface area of 150rr? /m3 or more and a medium particle size carrier with a void ratio of 50% or more is filled.

Reference numeral 16 denotes a water spray nozzle pipe for spraying water on the upper packed bed portion 15b to clean it.

The carrier filled in the lower and upper packed layer parts 15a and 15b may be made of a material other than ceramic, such as a polymer or fiber activated carbon, as long as it has pores on its surface and has high water retention. You can. Further, the shape may be granular, lattice, Raschig ring, columnar, crushed stone, or the like.

The microorganisms that can be attached to such carriers may be those that have the same oxidative decomposition function as the microorganisms that have been used conventionally, but for more efficient processing, for example, bacteria belonging to the genus Thiobacillus, Thiobacillus thioparus. It is desirable to use

Next, the present invention configured as described above will be explained in detail.

First, the cleaning water tank 12 and the stirring layer 12a are filled with cleaning water, which is neutral water, and then the gas to be treated IO is introduced through the inlet 13. At this time, the supplied gas to be treated 10 is supplied to the lower and upper packed layer portions 15a.

The gas is discharged into the atmosphere from the exhaust port 14 via the gas 15b, and first, the malodorous components in the gas are decomposed by microorganisms in the upper packed bed section 15b. The generated components in this case are represented by the following:

NH-+N SH0 H2S-H2SO4, S CHSH-+HSo, H2O, Co2(CH)
5-4 HSo, H2O, CO2 Next, the above-mentioned products are washed into the upper packed bed section 1 by washing water periodically sprinkled from the water spray nozzle pipe 16 to maintain the activity of microorganisms.
It is washed away from 5b. Therefore, the upper filled layer part 15
Since the washing water flowing down b contains acid decomposed and produced by microorganisms, this acidic washing water is sprayed onto the lower packed bed section 15a located below to wash it. The acidic cleaning water is used for cleaning the lower packed bed section 15a. In the lower packed bed section 15a, the acidic cleaning water and the gas to be treated 1O come into gas-liquid contact, so that basic malodorous components such as ammonia, methylamine, dimethylamine, trimethylamine, etc. contained in the gas to be treated 1O are removed. It is neutralized and removed from the gas to be treated. As a result,
Since the gas to be treated 10 from which most of the basic malodorous components have been removed in the lower packed bed section 15a reaches the upper packed bed section 15b, the load on the upper packed bed section 15b can be greatly reduced. I can do it.

In addition, the particle size of the carriers filled in the lower and upper packed layer parts 15a and 1Sb is made larger in the lower packed layer part 15a than in the upper packed layer part 15b, so that the void ratio is larger, that is, the gap is larger. Since the cross-sectional area is made large, it is possible to reduce clogging of the lower packed bed section 15a due to sludge generated when malodorous components are decomposed by microorganisms in the upper packed bed section 15b. Furthermore, since the carrier of the lower filled layer section 15a has a larger specific surface area with respect to ventilation resistance than the carrier of the upper filled layer section 15b,
The physicochemical reaction during the gas-liquid contact is efficiently carried out.

Then, the gas to be treated [θ
After neutralizing and removing basic malodorous components therein, the washing water falls into a washing water tank 12 provided at the bottom of the deodorizing tower 11.

The cleaning water in the cleaning water tank 12 is used repeatedly to clean the upper packed bed section 15b and to maintain the activity of the microorganisms, and the pH value and salt concentration of this circulating cleaning water are maintained to maintain the activity of the microorganisms. , a neutralizing agent is put into the stirring tank 12a.

It is preferable that the upper packed bed section 15b has a structure that is advantageous for decomposition by microorganisms as described above.
By fixing and retaining microorganisms that meet these values, basic malodorous components, acidic malodorous components that cannot be removed in the lower packed bed section 15a, and neutral malodorous components that cannot be removed in the lower packed bed section 15a are decomposed. .

[Effects of the Invention] As described above, the present invention provides a deodorizing tower with an upper packed bed section that performs microbial decomposition of malodorous components, and a cleaning solution containing acid generated in this packed bed section. It is formed with a lower packed layer that neutralizes and removes basic malodorous components using acidic washing water that has absorbed acidic malodorous components with water, and deodorizes using one packed bed having these two types of packed bed sections. Because it performs this process, it is possible to reduce the load on the upper packed bed while taking advantage of the low processing costs of conventional biological methods. Efficiently removes acidic and malodorous components, even against large gases.
Since basic malodorous components can be deodorized and neutral malodorous components can be reliably deodorized, and no special accessory equipment is required, the device can be made smaller and simpler.

In addition, the grain size of the carrier in the lower and upper packed layer portions is made gradually larger toward the lower packed layer portion than the upper packed layer portion, so that the void ratio, that is, the cross-sectional area of the gap gradually increases. This has the effect of reducing clogging of the lower packed bed section due to sludge generated when malodorous components are decomposed by microorganisms in the upper packed bed section.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a conventional gas deodorizing apparatus. lO... Gas to be treated, 11... Deodorizing tower, 12...
Washing water tank, 15... Filled bed, 15a... Lower packed layer section, 15b... Upper filled layer section.

Claims (1)

[Claims] An inlet for the gas to be treated and a cleaning water tank are provided at the bottom, a discharge port for the processing gas is provided at the top, and a packed layer made of a large number of carriers is provided between the discharge port and the cleaning water tank. A gas deodorizing device that includes a formed deodorizing tower and deodorizes a gas to be treated fed through the inlet, the gas deodorizing device having a function of removing malodorous components by a physicochemical method located below the packed bed. a lower first packed bed section;
It is formed with an upper packed bed part located above the packed bed part, which is sprayed with washing water and has the function of removing malodorous components by a biological method, and the particle size of the carrier in these packed bed parts is A gas deodorizing device characterized in that a lower packed bed section is larger than an upper packed bed section.