JPS5861822A - Deodorizing device for gas - Google Patents

Abstract

PURPOSE:To deodorizes gases to be treated efficiently by injection of ozone at a specified concn. by providing a buffer tower in the fore stage of a deodorozing tower which combines a deodorizer deposited with a bromine compd. and ozone thereby eliminating the fluctuations in the concn. of malodorous components. CONSTITUTION:Gases to be treated which have malodors are introduced into a buffer tower 7 like an arrow A, where the gases contact with the buffer agent 8 in the tower 7 and the concn. of the malodorous components is leveled off. Thereafter the ozone generated in an ozone generator 3 is injected into the gases through an ozone piping 6 like an arrow B, then the gases after the buffering contg. a prescribed concn. of ozone contact with a deodorizer 5 deposited with a bromine compd. in a deodorizing tower 4, whereby the gases are deodorized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to gas deodorization using ozone, and has been further evaluated to achieve high performance by combining ozone, a chemical deodorizer, with an adsorbent for malodorous substances such as activated carbon impregnated with a bromine compound. This is an energy-saving dry type gas deodorizing device.

Conventionally, there has been a device of this type as shown in FIG. FIG. 1 is a flow diagram showing a conventional gas deodorizing device.
In the figure, (1) is a fan that collects rapidly increasing gas to be treated in a duct, (3) is an ozone generator, and (4)
is a deodorizing tower, the inside of which is filled with a deodorizing agent (5) impregnated with a bromine compound. (6) is an ozone pipe, which connects the ozone generator (3) and the duct (2).

I will explain the operation shortly. After the foul-smelling gas to be treated is introduced into the duct) (21 by fan +1) as shown by arrow A, ozone is generated at the inlet side of fan (1-1).
The ozone generated by +31 is mixed into the gas to be treated at a predetermined concentration through the ozone pipe (6) as shown by arrow B, and is led to the deodorizing tower (4). The deodorizing tower (4) K is filled with a deodorizing agent (5) impregnated with a bromine compound, and the gas to be treated comes into contact with the deodorizing agent (5) for usually 0.3 to 1.5 seconds.

When the deodorizer (5) is filled with, for example, activated carbon impregnated with hydrogen bromide (HBr).

On its surface, the deodorizer (5) acts with ozone in the gas to be treated as shown in the chemical equation (1) below to produce bromine (Brl).
will occur.

2HB r +03-+Br@ +H10+01
- (1) The generated bromine oxidizes malodorous substances in the gas to be treated on the surface of the deodorizer (5), producing odorless or foreign substances with a significantly reduced degree of odor. To illustrate the deodorizing reaction against malodorous components, the following (2)
) to (4).

Ammonia 2NH3+ 3 B r2 →N2 + 6HB r
= (2) Hydrogen sulfide His +Brx→S+2HBr =
(3) or H Snow S+3Brs+2HzO→80g+6HBr
-= In (41 chemical equations (2) to K), bromine returns to hydrogen bromide and undergoes the ozone oxidation reaction according to equation (1) again.

In the above-mentioned conventional gas deodorizing equipment, the amount of ozone to be added to the gas to be treated must be at least the amount necessary to oxidize the malodorous substances contained in the gas to be treated. The types and concentrations of malodorous gas components in exhaust gas generated from wastewater treatment plants and sewage treatment plants vary greatly depending on the amount and condition of water to be treated and the operating conditions of water treatment equipment and sludge treatment equipment. In some cases, the concentration may increase or decrease by more than three orders of magnitude over time. Therefore, constantly injecting the required amount of ozone requires a large-scale ozone generator, which increases equipment costs and power consumption, making it uneconomical. There were drawbacks such as the fact that it was not easy to do so.

This invention was made in order to eliminate the drawbacks of the conventional gas deodorizing equipment as described above, and instead of providing a buffer group at the front stage of the conventional deodorizing tower, it eliminates the rapid fluctuation in the concentration of malodorous components. The object of the present invention is to provide a gas deodorizing device that can deodorize a gas to be treated with a constant ozone injection concentration.

An embodiment of the present invention will be described below with reference to the drawings. Second
FIG. 1 is a flowchart showing an embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

(7) is a buffer group provided at the front stage of the gas deodorizing device shown in FIG. , (8) is the buffer filled in the container.

In a gas deodorizing device configured as described above.

The foul-smelling gas to be treated is buffered as shown by arrow A (7).
The ozone generator (3)
The ozone generated in the ozone pipe (
6), and the deodorizing tower (4) is injected as in the case of Fig. 1.
In the process, the deodorizer with all the bromine compounds attached (contacts with the group,
Deodorized.

) of the buffering agent, there is a significant lI! in the gas to be treated! Adsorption ability for major malodorous components that cause temperature fluctuations □It is preferable to use a material that has a large strength and has an effective adsorption ability for multiple bad odor components. For example, when dealing with hydrogen sulfide, which has the most severe concentration fluctuations, the buffering agent may be various types of activated carbon such as commercially available wood-based coal or coconut shell, or sodium hydroxide or iodide, which chemically reacts with hydrogen sulfide. Porous carriers such as the above activated carbon, activated alumina, synthetic zeolite, activated clay, etc., impregnated with chemicals such as sodium and potassium iodide can be used.

If it is necessary to treat hydrogen sulfide and methyl mercaptan at the same time, activated carbon not impregnated with the above-mentioned chemicals or a porous adsorbent impregnated with iodide can be used as the buffer.

Furthermore, when the target is a basic malodorous substance such as ammonia or trimethylamine, a porous adsorbent impregnated with an aqueous solution of a mineral acid such as #A acid or sulfuric acid may be used. Furthermore, if both hydrogen sulfide and monoammonia are treated and round, two types of buffers for hydrogen sulfide and ammonia are arranged in series in the flow direction of the gas to be treated, or tIA ferrous,
*A porous adsorbent impregnated with a heavy metal salt that dissolves in water and exhibits acidity, such as ferric oxide, is used.

Next, the ability of the buffer to smooth the concentration of malodorous components will be explained. When the partial pressure of the malodorous components in the gas to be treated is p*tm, and the amount of malodorous components that can be adsorbed by 1 kg of buffer is ω~, then empirically, the relationship between ω and p is expressed by equation (5). A relationship is established.

ω= *p-(5) Here, a and b are constants determined by the adsorbent, the target malodor component, the adsorbent temperature, etc.

The malodorous component is hydrogen sulfide, and the adsorbent is hydroxide.) As an example of activated carbon impregnated with IJium, (Equation 5 is as follows.

ω = 2.30 po・” (20℃)...Chapter)
In equation (6), if the buffer is in contact with the gas to be treated for a long time and adsorbs 25 cm (ω = 0.25) of hydrogen sulfide, then the equilibrium hydrogen sulfide back pressure of the buffer is is 2
．． 14×10 atm. Therefore, the hydrogen sulfide concentration in the gas to be treated is 2.14 x 10 atm
At this point, the adsorption capacity of the seeded hydrogen by the buffer (8) is generated, and the concentration of hydrogen sulfide in the gas to be treated decreases compared to that entering the buffer tower (7). 14
The concentration will be close to X10 atmlc. On the other hand, the buffer tower (
7) Hydrogen sulfide #1 degree in the gas to be treated entering is 2.14X
When it becomes less than 10"" ata+ (equilibrium back pressure), the hydrogen sulfide adsorption ability of buffer (β) disappears, and conversely, the hydrogen sulfide adsorption ability of buffer (8) disappears.
Hydrogen sulfide is desorbed from the hydrogen sulfide and introduced into the deodorizing tower (4).
Approaching tm. Even if the malodorous component is methyl mercaptan or ammonia, by appropriately selecting a buffering agent, the same effect as the above-mentioned a-buffering of hydrogen sulfide concentration can be achieved.

The filling amount of the buffering agent (8) varies depending on the absorption capacity of the target malodorous component, but in order for effective adsorption and desorption to occur, contact with the gas to be treated for 1 second or more is usually required. The amount of filling should be such that the time is maintained. When smoothing hydrogen sulfide, the filling specific gravity of activated carbon impregnated with sodium hydroxide or potassium iodide used as a buffer (8) is 500#/m.
', the contact time with the gas to be treated is 1 second, and ω = 0.25 in equation (6) is 9 (Hz S )/kfi (if the buffer is used, the hydrogen sulfide concentration in the gas to be treated is 10
10-' atm K rises.

The buffer adsorbs more than 2.14 X 10 aim of hydrogen sulfide and its ability lasts until reaching ω = 0.32. The duration T of the buffering effect is given by the amount of gas to be treated as I N −/ssj.

3.600X1/22.4XΔpX34XTs =50
0X(0,32〒0.25)ΔF(10-2,14)
XIO-' ・°・Tt 〉815 I(r, that is, more than 815 hours.

-10,000, when the hydrogen sulfide concentration decreases to 0.5 X 10-' atm, ω=0.195 (jl=o, 5
10 - the value corresponding to 'atm) until K, *of the shock agent)
Hydrogen sulfide continues to be desorbed from T, for a period of time T.

3600X1/22.4X(2,14-0,5)XIO
X34XT*>500 (0,25-0,195) ”Ts>3070Hr, that is, over 3070 hours &
Ru.

Regarding the estimated duration of the buffering effect mentioned above, since the concentration of malodorous components contained in the final waste gas generated from human waste treatment plants and sewage treatment plants fluctuates every 24 hours a day, The duration of the buffering action is 3 to 4 times longer than the required amount. Therefore, it exhibits a sufficient buffering effect.

In the above embodiment, the buffer tower (7) is provided at # of the fan (1), but the fan (1) may be placed in front of the buffer tower (7). Also, the deodorizing agent (
5) Bromine compounds to be impregnated with K include hydrogen bromide, alkali metal bromides such as sodium bromide, potassium bromide, and lithium bromide, or alkaline earth metal bromides such as magnesium bromide and calcium bromide. One or more water-soluble substances of bromides can be used.

The gas deodorizing device of the present invention is applicable to deodorizing devices for malodorous gas and other odorous gases generated from human waste treatment plants and sewage treatment plants.

As described above, according to the present invention, the concentration of malodorous components in the gas to be treated is moderated by SFr, so when the gas to be treated is passed through the buffer tower (7) K, the concentration of malodorous components in the gas to be treated is reduced. It is smoothed and introduced into the deodorizing tower (4)K. Therefore, there is no need to change the ozone concentration in synchronization with the concentration of malodorous components in the gas to be treated, and there is no need to add a large excess of ozone. All you have to do is supply it. Therefore, the ozone generator (3)
Not only does it become smaller, but it also becomes smaller.

This has the effect of saving energy for the entire deodorizing device.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a conventional dry deodorizing device using both ozone and bromine compound impregnation, and FIG. 2 is a flowchart showing a gas deodorizing device according to an embodiment of the present invention. In the diagram, (1) is a fan, (3) is an ozone generator, and (4)
is a deodorizing tower, (5) is a deodorizing agent, (7) is a buffer group, and (2) is a buffering agent. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - (1 other person)

Claims (1)

[Scope of Claims] (1) The production of malodorous components in odorous gas by temporarily adsorbing and removing the malodorous components in odorous gas or re-releasing the removed malodorous components. A buffer tower for pIm, a means for mixing ozone into the gas that has passed through the buffer tower, and a deodorizing tower filled with a deodorizer impregnated with a bromine compound and arranged so as to be in contact with the gas mixed with the ozone. A gas deodorizing device characterized by: C) The buffer tower contains activated carbon or sodium hydroxide, #A acid,
The gas deodorizing device according to claim 1, characterized in that the device is filled with an adsorbent in which a porous carrier is impregnated with potassium iodide or sodium iodide. (3) Bromine compounds include hydrogen bromide, sodium bromide, potassium bromide, lithium bromide, and magnesium bromide. The gas deodorizing device according to claim 1 or 2, wherein the gas deodorizing device is a water-soluble substance of lfi or higher class among calcium bromide and calcium bromide.