JPH07253208A - Harmful gas absorbing and removing device - Google Patents

Abstract

PURPOSE:To provide a harmful gas absorbing and removing device, provided with a simple structure suitable for a small-size incinerator and the like especially and capable of absorbing and removing harmful gas in exhaust gas surely without generating any secondary public pollution. CONSTITUTION:A reaction chamber 12, receiving granular slaked lime S under a condition capable of being contacted with high-temperature exhaust gas discharged out of a combustion furnace, is provided in a main body 10 connected to the exhaust part of the combustion furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for absorbing and removing harmful gas contained in exhaust gas from a combustion furnace, particularly an incinerator.

[0002]

2. Description of the Related Art Exhaust gas discharged from combustion furnaces such as incinerators contains chlorine compounds such as HCl, fluorine compounds such as HF, and harmful gases such as sulfur oxides such as SO ₂ and SO _3. Therefore, it is necessary to remove these harmful gases. Conventionally, as a device for removing each of the harmful gases from the exhaust gas of the combustion furnace, a device using slaked lime is generally used. That is, each harmful gas is Ca, which is the main component of slaked lime.
Each of them reacts with (OH) ₂ as shown in the following reaction formula to be rendered harmless and removed from the exhaust gas.

2HCl + Ca (OH) ₂ → CaCl ₂ + 2H ₂ O 2HF + Ca (OH) ₂ → CaF ₂ + 2H ₂ O SO ₂ + Ca (OH) ₂ → CaSO ₃ + H ₂ O SO ₃ + Ca (OH) ₂ → CaSO ₄ + H ₂ O In the apparatus utilizing the above reaction, a wet type in which an aqueous solution in which slaked lime is dissolved in water is reacted while contacting with exhaust gas,
There is a dry type in which fine powder of slaked lime is blown into the exhaust duct to react while being mixed.

[0004]

However, in the case of the former wet type apparatus, a large amount of sludge containing reaction products is generated, and it is necessary to discharge excess water. Therefore, in order to prevent secondary pollution such as water pollution, there is a problem that equipment for sludge and sewage treatment, which is larger than a device for removing harmful gas, is required.

In the case of the dry method, since the fine powder of slaked lime itself which has reacted with harmful gas is dust which causes secondary pollution, in order to prevent secondary pollution such as air pollution, the harmful gas is also required. An electrostatic precipitator, bag filter, etc., which are larger than the removal device, are required. Moreover, since the above electrostatic precipitators and bag filters cannot withstand high temperatures of 300 ° C or higher, high temperature exhaust gas from the combustion furnace (700 to 900 ° C) is used.
There is also a problem in that a cooling device for cooling the temperature to 300 ° C. or less is required, and the equipment becomes large-scale.

For this reason, the conventional apparatus is not suitable for an incinerator, which is often a relatively small one among combustion furnaces, and the exhaust gas of a small incinerator is discharged into the atmosphere while containing harmful gas. Is the current situation. The purpose of this invention is
An object of the present invention is to provide a harmful gas absorption / removal device which has a simple structure particularly suitable for a small incinerator and the like, and which can surely absorb and remove the harmful gas in the exhaust gas without causing secondary pollution.

[0007]

In order to solve the above-mentioned problems, a harmful gas absorption / removal device of the present invention is provided with a high temperature exhaust gas discharged from a combustion furnace in a main body connected to an exhaust part of the combustion furnace. It is characterized in that a reaction chamber for accommodating granular slaked lime is provided in a contactable state.

[0008]

According to the harmful gas absorption / removal device of the present invention having the above-mentioned structure, the high-temperature exhaust gas discharged from the combustion furnace is brought into direct contact with the slaked lime contained in the reaction chamber.
Despite the use of granular slaked lime with a small specific surface area, it efficiently and reliably absorbs and removes harmful gases in the exhaust gas at a reaction rate comparable to or higher than that of fine powder. it can.

As mentioned above, slaked lime is granular,
Since it is stored in the reaction chamber, it does not generate sludge or dust that causes secondary pollution, unlike the aqueous solution of slaked lime or fine powder. Therefore, these processing devices are unnecessary, and cooling equipment is also unnecessary, and the device can be simplified. In addition, a large amount of slaked lime aqueous solution and fine powder is consumed in one treatment, whereas granular slaked lime can be repeatedly used over a relatively long period of time, so it is better than a special form such as fine powder. In addition to being inexpensive and not requiring a sludge and dust treatment device, a cooling device, etc. as described above, there is also an advantage that the running cost of the device can be reduced.

[0010]

EXAMPLE A harmful gas absorption / removal apparatus of the present invention will be described below.
An embodiment will be described with reference to the drawings. Figure 1
As shown in (a) and (b) and FIG. 2, the harmful gas absorption / removal device 1 of this embodiment includes a lower body 10 directly connected to an exhaust port F1 on the upper surface of an incinerator F, and an upper portion of the lower body 10. And an upper body 11 connected to. Further, a chimney C is connected to the upper body 11.

The lower main body 10 is formed in a substantially cylindrical shape having a large diameter portion 10a in the middle thereof, and a reaction chamber 12 containing granular slaked lime S is opened from an opening 10b formed on the side surface of the large diameter portion 10a. Is inserted and arranged in the large diameter portion 10a.
The reaction chamber 12 has a bottom plate 12a formed into a net-like shape which allows exhaust gas from the incinerator F to pass through but does not allow granular slaked lime S to pass through, and is formed in a shallow box shape without a top plate. One of the side surfaces is a lid 12b that closes the opening 10b.

By fixing the lid 12b and the edge 10c of the opening 10b with the bolt b, the opening 10b is closed and the reaction chamber 12 is fixed in the large diameter portion 10a of the lower body 10. There is. Since the reaction chamber 12 can be pulled out from the large-diameter portion 10a of the lower body 10 simply by removing the bolt b, there is an advantage that the slaked lime S can be easily replaced.

Reference numeral 12c in the drawing is a handle for pulling out or inserting the reaction chamber 12 from the large diameter portion 10a of the lower body 10. The size of the granular slaked lime S contained in the reaction chamber 12 is not particularly limited, but is preferably about 10 to 30 mm. The size of granular slaked lime S is 10 mm
When the amount is less than the above, the space between the respective slaked lime particles becomes too small when housed in the reaction chamber 12, and there is a possibility that the passage of exhaust gas may be hindered. On the contrary, when the size of the granular slaked lime S exceeds 30 mm, the specific surface area becomes too small, and the harmful gas in the exhaust may not be sufficiently removed.

The upper main body 11 is formed in a tubular shape with an orifice portion 11a having a small diameter in the middle thereof, and a substantially L-shaped air nozzle 13 is provided below the upper main body 11, and the tip thereof is upward, that is, the orifice portion 11a. The air blower B is connected to the air nozzle 13 as shown in FIG. The upper body 11 is a blower B
1 to drive air from the tip of the air nozzle 13 into the orifice portion 11 as shown by the dashed line arrow in FIG.
It is jetted in the direction of a, whereby the upper and lower bodies 10, 11
This is for generating an ascending airflow inside and discharging high temperature exhaust gas containing harmful gas from the incinerator F as shown by a black arrow in the figure.

In the upper body 11, by adjusting the amount of air blown from the blower B, the amount of exhaust gas from the incinerator F, that is, the mass velocity of exhaust gas passing through the slaked lime S, which will be described later, can be controlled. it can. In order to process the exhaust gas from the incinerator F using the harmful gas absorption / removal device 1 of this embodiment, which is made up of the above-mentioned components, first, the blower B is operated and the incinerator F is ignited.

Then, an ascending air current is generated in the upper and lower main bodies 10 and 11, and as shown by a black arrow in FIG. 1 (a), a high temperature exhaust gas (700 to 9) containing harmful gas is emitted from the incinerator F.
(About 00 ° C) is discharged. Then, the discharged high-temperature exhaust gas comes into contact with the granular slaked lime S in the reaction chamber 12, and after various harmful gases are absorbed and removed according to the reaction formula, as shown by the white arrow in the figure, It is diffused into the atmosphere through the upper body 11 and the chimney C.

At this time, the temperature (° C.) of the exhaust gas, the mass velocity (kg / m ² H) of the exhaust gas passing through the slaked lime S, and the absorption rate (%) of the harmful gas are shown by a solid curve in FIG. 3, for example. Have a relationship. In other words, the reaction rate increases exponentially with increasing temperature, so if the mass velocity is the same, the higher the temperature of the exhaust gas, the higher the absorption rate of harmful gas. Since the physical average is controlled by the harmonic average of the diffusion rate, the lower the mass velocity, the higher the absorption rate of harmful gas when the temperature of the exhaust gas is the same.

To give specific values in the case of FIG. 3, the inner diameters of the upper and lower main bodies 10 and 11 are 300 mm, the inner diameter of the large diameter portion 10a of the lower main body 10 is 700 mm, and the height of the lower main body 10 is 85 mm.
0 mm, the size of slaked lime S is 10 to 30 mm, the amount of slaked lime S in the reaction chamber 12 is 70 g, and the layer thickness of slaked lime S in the reaction chamber 12 is 150 mm. In this case, the temperature of the exhaust gas is 800
When the temperature is set to ° C and the mass velocity of the exhaust gas passing through the slaked lime S is set to 1000 kg / m ² H, the absorption rate of harmful gas is 54%.

The construction of the harmful gas absorption / removal device of the present invention is not limited to the above-described embodiment. For example, the harmful gas absorption / removal device of the present invention may be connected to the exhaust part of the combustion furnace, and the exhaust part may be the exhaust port of the combustion furnace or the exhaust path connected to the exhaust port. To be That is, the harmful gas absorption / removal device of the present invention may be directly connected to the exhaust port F1 of the incinerator F (combustion furnace) as in the embodiment shown in the figure, but it is arranged in the middle of the duct connected to the exhaust port. It doesn't matter.

In the apparatus of the illustrated embodiment, the slaked lime S is stored in the box-shaped reaction chamber 12 that can be pulled out from the lower body 10 and inserted. Is not limited to this. Further, the apparatus of the embodiment shown in the figure was composed of a lower main body 10 having the reaction chamber 12 and an upper main body 11 to which a blower B for exhaust was connected. When the apparatus of the present invention is incorporated in the furnace, the upper body 11 can be omitted.

The apparatus of the present invention can be connected to a combustion furnace other than the incinerator. In addition, various design changes can be made without changing the gist of the present invention.

[0022]

As has been described in detail above, the harmful gas absorption / removal device of the present invention has a simpler structure than the conventional ones, and moreover, can secure harmful gas in exhaust gas without causing secondary pollution. Can be absorbed and removed. Therefore, the harmful gas absorption and removal device of the present invention is suitable for various combustion furnaces such as small incinerators, and is extremely useful for removing harmful gas from the exhaust gas of these combustion furnaces to prevent air pollution. is there.

[Brief description of drawings]

FIG. 1 (a) is a sectional view showing the internal structure of an embodiment of the harmful gas absorption / removal apparatus of the present invention, and FIG. 1 (b) is a front view showing the external appearance of the apparatus of the above embodiment.

FIG. 2 is a schematic view showing a state in which the apparatus of the above-mentioned embodiment is attached to an incinerator as a combustion furnace.

FIG. 3 is a graph showing the relationship between the temperature of exhaust gas, the mass velocity of exhaust gas that passes through slaked lime, and the absorption rate of harmful gas in the apparatus of the example.

[Explanation of symbols]

 1 Toxic gas absorption and removal device 10 Lower body 11 Upper body 12 Reaction chamber S Slaked lime

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B01D 53/34 134

Claims (1)

[Claims] 1. A device for absorbing and removing harmful gas contained in exhaust gas of a combustion furnace by reacting with slaked lime,
Absorption of harmful gas, characterized in that a reaction chamber for accommodating granular slaked lime is provided in the body connected to the exhaust part of the combustion furnace in a state in which it can come into contact with high-temperature exhaust gas discharged from the combustion furnace. Removal device.