JPH04260408A - Bag filter device with gas cooling function - Google Patents

Abstract

PURPOSE:To provide a bag filter device able to efficiently remove harmful substances such as dioxin by enabling low temperature treatment in the bag filter without causing low temperature corrosion of a waste gas treatment device. CONSTITUTION:In a bag filter device wherein waste gas A is introduced into a dust collection chamber 2 and dust is removed in a bag filter 5, a cooling chamber 1 having a two-fluid spray nozzle 3 is provided at the entrance of said chamber 2 to cool the gas A to an optimum treatment temperature. As a result, dioxin can be effectively separated without causing low temperature corrosion and moreover said chamber 1 as it is can be incorporated into an existing waste gas device in place of an electrostatic precipitator.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bag filter device with a gas cooling function, and more particularly to a bag filter device with a gas cooling function used as an exhaust gas treatment device of a garbage incinerator.

0002

2. Description of the Related Art Hazardous organic chlorine compounds such as PCDD (polychlorinated dibenzodioxin) and PCDF (polychlorinated dibenzofuran) have recently attracted particular attention as highly toxic hazardous substances. These toxic organic chlorine compounds (hereinafter sometimes simply referred to as dioxins) are known to be generated as by-products of agricultural chemicals or when incinerating municipal waste, etc., and exhaust gas treatment equipment that separates them is required. usually has a built-in bug filter.

FIG. 7 is a system diagram of such an exhaust gas treatment device. This device is mainly composed of an incinerator 21, a gas cooling tower 22, an air preheater 23, and a bag filter 26 connected to the incinerator 21 in sequence. 25 is a neutralizer supply pipe. For example, 75
The combustion exhaust gas at 0 to 950°C is cooled to, for example, 230 to 250°C in the gas cooling tower 22 and the air preheater 23,
Neutralizer supply pipe 2 is an alkaline agent for neutralizing acidic components.
After being added from 5, it enters the downstream bag filter 26,
Here, dioxins are physically collected together with neutralization reaction products such as CaCl2 and remaining dust.

[0004] Harmful organic chlorine compounds such as PCDD and PCDF are generated or regenerated in an atmosphere of 300°C or higher.
When cooled to temperatures below 0° C., for example below 250° C., it condenses or crystallizes and can be physically separated as a solid, but the processing temperature is preferably as low as possible.

[0005] However, the exhaust gas is
When the exhaust gas is cooled to a temperature of In order to prevent such low-temperature corrosion, bag filter treatment is performed at 180 to 250°C.

[0006] In addition, in many of the exhaust gas treatment equipment that existed before environmental pollution caused by dioxins became a problem, an electric precipitator was used alone as a dust collector, and there is a study to change this electric precipitator to a bag filter. However, since the exhaust gas temperature at the inlet of the electrostatic precipitator is higher than the permissible or optimal processing temperature of the bag filter, there is a problem that it cannot be easily converted.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, to realize low-temperature treatment in a bag filter without causing low-temperature corrosion of a series of exhaust gas treatment devices, and thereby to improve the performance of PCDD, An object of the present invention is to provide a bag filter device with a gas cooling function that efficiently removes harmful organic chlorine compounds such as PCDF.

[0008]

[Means for Solving the Problems] The present inventor has discovered that the difference between the precipitator inlet temperature in a series of conventional exhaust gas treatment devices and the optimal processing temperature of a bag filter for separating dioxins is 1.
Focusing on the fact that the temperature is relatively small at around 00℃, as a result of intensive research, we found that by placing a small cooler at the inlet of the bag filter, we were able to perform low-temperature processing in the bag filter without causing low-temperature corrosion of each equipment component. The present inventors have discovered that this makes it possible to improve the separation efficiency of dioxin, and have arrived at the present invention.

That is, the present invention is a bag filter device that introduces exhaust gas into a dust collection chamber and removes dust using a filter cloth,
The present invention is characterized in that a gas cooling chamber is provided at the entrance of the dust collection chamber to cool the exhaust gas temperature to the optimal processing temperature of the bag filter.

0010

[Function] By providing a cooling chamber at the inlet of the dust collection chamber of the bag filter device, the bag filter optimally processes exhaust gas of, for example, 250 to 300°C flowing out from the air preheater, etc. upstream of the bag filter. Temperature, e.g. 180-20
Since it can be cooled to 0°C, the dioxins in the exhaust gas are completely liquefied or crystallized and efficiently collected. In addition, by using this bag filter device with a gas cooling function, there is no need to cool down the exhaust gas temperature up to the bag filter device in the series of exhaust gas treatment devices more than necessary, which reduces the temperature of the exhaust gas caused by water condensation in the exhaust gas. Cold corrosion of equipment components is avoided.

In the present invention, a small two-fluid spray nozzle, for example, is used as the cooling device disposed in the cooling chamber at the entrance of the dust collection chamber. This two-fluid spray nozzle uses air as the spray medium to spray water in the form of a mist, and exhibits a sufficient cooling effect with a small-capacity cooling section. The sprayed water completely turns into water vapor and effectively cools the exhaust gas, for example, the exhaust gas flowing in at 250°C is cooled to about 180°C.

In the present invention, by arranging a neutralizer addition device together with a two-fluid spray nozzle in the cooling chamber at the entrance of the dust collection chamber, acidic components in the exhaust gas are fixed as neutralization reaction products and separated together with dioxins. Therefore, the regeneration of dioxin can be suppressed. Also,
Instead of the two-fluid spray nozzle, a so-called ultrasonic spray nozzle that sprays water using ultrasonic waves may be used.

[0013]

EXAMPLES Next, the present invention will be explained in more detail with reference to examples.

[0014]

Embodiment 1 FIG. 1 is an explanatory diagram of a bag filter device with a gas cooling function showing one embodiment of the present invention, and FIG. 2 is a plan view thereof. This device includes a gas cooling chamber 1, an exhaust gas introduction pipe 6 connected to the upper part thereof, a two-fluid spray nozzle 3 for fine particles and a neutralizing agent supply pipe 4 provided near the connection part.
Water supply pump 7 that sends spray water to the two-fluid spray nozzle 3
and a flow rate regulating valve 8 provided in the spray water supply line 12, adjacent to the gas cooling chamber 1 via a partition wall 11, and connected to the bottom of the gas cooling chamber 1 by the entire width of the lower part of the partition wall 11. a temperature detector 9 provided at the entrance of the dust collection chamber 2, a large number of bag filters 5 made of, for example, glass fiber arranged in the dust collection chamber 2, a cooling chamber 1 and a temperature detector 9 provided at the entrance of the dust collection chamber 2; It mainly consists of a scraper conveyor 10 commonly provided at the bottom of the dust chamber 2.

In such a configuration, the exhaust gas introduction pipe 6
Exhaust gas A cooled to 250°C by an upstream air preheater, for example, is introduced into the gas cooling chamber 1 from
It is cooled to ~200°C, and the dioxins in the exhaust gas liquefy or crystallize. At this time, the exhaust gas temperature is detected by the temperature detector 9 disposed at the connection between the cooling chamber 1 and the dust collection chamber 2, and the amount of water sprayed by the two-fluid spray nozzle 3 is controlled based on this detected value. Further, from the neutralizing agent supply pipe 4, slaked lime, for example, is added as a neutralizing agent for neutralizing acidic components in the exhaust gas. The exhaust gas A, which has been cooled to the optimum processing temperature of the bag filter and to which the neutralizing agent has been added, flows into the dust collection chamber 2 from the bottom of the cooling chamber 1, and the acidic components are neutralized on the bag filter 5. Reaction products such as CaCl2 are removed, and dust and dioxins adhering to it are separated, forming processing gas B and passing through the extraction pipe 1.
3, and is discharged to the outside of the system via, for example, an induced blower. On the other hand, the solid matter containing dioxins collected by the bag filter 5 is periodically brushed off, for example, by pulse air, and then discharged from the dust collection chamber 2 to the outside of the system by the scraper conveyor 10, and is treated separately. .

According to this embodiment, the bag filter device is provided with the gas cooling chamber 1, and by cooling the exhaust gas A using, for example, the two-fluid spray nozzle 3, the temperature of the exhaust gas flowing into the dust collection chamber 2 is controlled by the bag filter. Since the temperature can be adjusted to the most suitable temperature for removing dioxins, for example, 180 to 200°C, harmful organic chlorine compounds such as dioxins can be efficiently removed. In addition, since the exhaust gas temperature can be adjusted just before the entrance to the dust collection chamber 2, there is no need to unnecessarily cool the exhaust gas temperature at the upstream of the bag filter device, such as a cooling tower or air preheater. Low-temperature corrosion can be avoided. Furthermore, by compactly integrating a bag filter device and a small gas cooling device, it can be directly incorporated into existing equipment as an alternative to the electrostatic precipitator of conventional exhaust gas treatment equipment, making it possible to take measures against dioxin economically. can.

Furthermore, according to this embodiment, the exhaust gas A cooled to a predetermined temperature in the cooling chamber 1 uniformly passes through the entire width of the lower part of the partition wall 11 and is dispersed in the dust collection chamber 2, thereby preventing bugs. The load on the filter can be made almost uniform.

[0018]

Embodiment 2 FIG. 3 is an explanatory diagram of a bag filter device with a gas cooling function showing another embodiment of the present invention, and FIG. 4 is a plan view of FIG. 3. This device differs from the first embodiment in that dust collection chambers 2a and 2b are provided on both sides of the cooling chamber 1, and the exhaust gas A cooled in the cooling chamber 1 is transferred between the cooling chamber 1 and the dust collection chambers 2a and 2b. The flow is uniformly distributed in two directions over the entire width below the partition walls 11a and 11b that partition the chambers 2a and 2b,
It flows into the dust collection chambers 2a and 2b.

[0019] In this embodiment as well, the same effects as in the first embodiment can be obtained.

[0020]

Embodiment 3 FIG. 5 is an explanatory diagram showing another embodiment of the present invention, and FIG. 6 is a plan view of FIG. 5.

[0021] In this bag filter device, the cooling chamber 1 is cylindrical, and around the cylindrical cooling chamber 1, a concentric donut-shaped dust collection chamber 2 is provided by hollowing out the cylindrical cooling chamber 1. The exhaust gas A flowing into the dust collection chamber 2 from the cooling chamber 1 is uniformly distributed in all directions below the partition wall 11 that forms the periphery of the cylindrical cooling chamber 1, and is uniformly distributed to the dust collection chamber 2. It flows in like manner.

According to this embodiment, in addition to the effects of the first embodiment, the dust collection efficiency is improved because there is no corner portion where the gas flow stagnates in the cooling chamber 1 and the dust collection chamber 2. Further, there is an advantage that the direction in which the processing gas is taken out after dust collection can be arbitrarily selected.

In this embodiment, the dust collection chamber 2 formed around the cooling chamber 1 may have a rectangular shape as in the first or second embodiment.

[0024]

[Effects of the Invention] According to the present invention, by providing the gas cooling chamber at the entrance of the dust collection chamber of the bag filter device, the temperature of the exhaust gas flowing into the dust collection chamber can be adjusted to the optimal processing temperature by the bag filter device. Therefore, harmful organic chlorine compounds can be efficiently removed. Furthermore, since the gas temperature can be adjusted at the entrance of the dust collection chamber, it is not necessary to cool down the exhaust gas temperature in a series of exhaust gas treatment devices more than necessary, and low-temperature corrosion can be avoided. Furthermore, since it can be directly incorporated into existing exhaust gas treatment equipment as a substitute for an electrostatic precipitator, it is possible to economically take measures against harmful organic chlorine compounds.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a bag filter device with a gas cooling function showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is an explanatory diagram showing another embodiment of the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is an explanatory diagram showing another embodiment of the present invention.

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

1...Cooling chamber, 2...Dust collection chamber, 3...Atomization spray nozzle, 4...
Neutralizer supply pipe, 5...bag filter, 6...exhaust gas introduction pipe,
7...Water supply pump, 8...Flow control valve, 9...Temperature detector, 10...Scraper conveyor, 11 Partition wall.

Claims (1)

[Claims] 1. A bag filter device that introduces exhaust gas into a dust collection chamber and removes dust using a filter cloth, wherein a gas cooling device is installed at the entrance of the dust collection chamber to cool the exhaust gas temperature to the optimum processing temperature of the bag filter. A bag filter device with a gas cooling function characterized by having a chamber.