JP2003245514A - Back washing device for bag filter and gas treatment device provided with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a back washing device for a bag filter and a gas treatment device able to avoid firing of gas when back washing of the bag filter. <P>SOLUTION: The back washing device 20a is provided with an inert gas feed means 23 for blowing out an inert gas onto a back surface side against a dust collection surface of the bag filter 6, and the gas treatment device 1a is provided with this back washing device. The inert gas feed means 23 is changed to a hydrogen feed means and the back washing device is constituted such that the bag filter 6 back-washed by water vapor. The back washing device is further provided with a gas return flow passage for taking-in a part of the gas passing through the bag filter and blowing out it. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bag filter backwashing apparatus for filtering a gasification gas produced in a combustion furnace or the like, and a gas processing apparatus including the bag washing apparatus.

[0002]

2. Description of the Related Art As a typical example of the structure and function of a conventional gas processing apparatus, a pulse jet blow-off type bag filter will be described with reference to FIG. In the figure, reference numeral 1 is an exhaust gas treatment device (gas treatment device), 2 is a container, 5
Is a dust discharge device, 6 is a bag filter, 10 is an IDF (In
duced Draft Fan), 20 is a backwash device for the bag filter 6, and T is soot and dust.

Conventionally, an exhaust gas treatment apparatus 1 provided in a refuse incineration facility or the like has a bag filter for removing soot dust T and acid gas contained in the exhaust gas, as well as slaked lime and special reaction agents mixed as chemicals. 6 is provided. The bag filter 6 is composed of a filter cloth 6 a, and collects dust such as the above-mentioned soot dust T by passing the exhaust gas sucked from the gas suction pipe 3 connected to the container 2. Then, the exhaust gas in the container 2 that has passed through the filter cloth 6a is
The gas is delivered from the gas delivery pipe 4 connected to the container 2 by the suction action of the IDF 10. The IDF 10 is a fan that sucks in exhaust gas and sends out the sucked exhaust gas.

The bag filter 6 will be described. The bag filter 6 is a type of dry unit type filter and is capable of collecting soot dust T or the like having a smaller particle size than the panel type or dry type roll-up type. In addition, since the dust collection area is wider than the air inlet area, the capacity for holding the dust T is large, and the passing speed through the filter cloth 6a is small, so the air resistance is small. There is.

As the exhaust gas treating apparatus 1 removes dust from the exhaust gas, the dust T, chemicals and the like gradually adhere to the filter cloth 6a. Then, the filter cloth 6a is clogged with the attached substances such as the soot dust T. For this reason, the compressed air is periodically sprayed onto the clean side of the filter cloth 6a, that is, the rear surface side with respect to the dust collecting surface, to remove the adhered matter.

[0006] As described above, the work of removing the soot dust T or the like adhering to the filter cloth 6a is generally called backwashing (also simply referred to as "backwashing") for the bag filter 6, and a device for performing this work. As shown in the figure, the backwash device 20
Is used.

The backwash device 20 includes an air compressor 22 for supplying compressed air, a backwash passage 21 for circulating the compressed air to the container 2, and a backwash control valve 26 for controlling spraying of the backwash air. The compressed air of about 0.1 to 0.3 MPa is used for backwashing. It should be noted that the adhered matter such as the dust T that has been washed away by the backwash is discarded to the outside of the container 2 by the dust discharge device 5 provided in the lower portion of the container 2.

[0008]

However, in the gasification system in which the waste gas or the like is exposed to a high temperature to be gasified to generate a gas serving as a fuel and the obtained gas is supplied, the above-mentioned backwash device 20 is used. There was a risk of fire in the backwash work at.

In the gasification system, since the gasification gas for removing dust is a gas containing combustible components, it is ignitable by being mixed with the air ejected for backwashing the bag filter 6. This is because it becomes a mixed gas.

The present invention has been made in view of the above circumstances, and provides a backwashing device for a bag filter which avoids ignition of gasified gas in backwashing the bag filter, and a gas treatment device including the backwashing device. With the goal. The present invention can be applied not only to the backwash of the pulse jet blow-off method but also to other backwash methods such as the reverse jet blow-off method.

[0011]

The present invention adopts the following means in order to solve the above problems. The invention according to claim 1 is a backwashing apparatus for a bag filter, which removes dust collected by passing a gasified gas through the bag filter, wherein an inert gas is provided on a back surface side of the bag filter with respect to a dust collecting surface. It is characterized in that it is provided with an inert gas supply means for ejecting.

With such a structure, the inert gas is blown out to the back surface side of the bag filter with respect to the dust collecting surface, and the deposits attached to the bag filter are removed. At the same time, the gasified gas that has passed through the bag filter and the inert gas are mixed with each other, and the inert gas does not cause ignition of the gasified gas when these are mixed.

According to a second aspect of the present invention, in a backwashing device for a bag filter that removes adhered substances collected by passing a gasified gas through the bag filter, the backside of the bag filter with respect to the dust collecting surface. It is characterized in that a steam supply means for ejecting steam is provided.

With such a structure, the water vapor is jetted to the back surface side of the bag filter with respect to the dust collecting surface, and the deposits attached to the bag filter are removed.
At the same time, the gasification gas that has passed through the bag filter and the water vapor are mixed, but the water vapor does not ignite the gasification gas when they are mixed. Further, the steam is likely to become water by being cooled, and the steam can be easily removed. Therefore, the gasified gas is not diluted with water vapor, and the calorific value is not reduced.

According to a third aspect of the present invention, in a backwashing device for a bag filter that removes dust collected by passing the gasified gas through the bag filter, the backwash device for the gasified gas that has passed through the bag filter is used. It is characterized in that a gas return flow path is provided for ejecting a part of the bag filter toward the back surface side with respect to the dust collecting surface of the bag filter.

With such a structure, the gasified gas that has passed through the bag filter and has been dust-removed is conducted through the gas return flow path and is ejected to the back surface side of the bag filter with respect to the dust collecting surface. Will be backwashed. In addition, a part of the gasified gas ejected from the gas return passage joins the gasified gas before being dust-removed by the bag filter. Ignition is not caused by the confluence of these gasified gases.

According to a fourth aspect of the present invention, there is provided a gas treatment device for filtering a gasified gas with a bag filter provided in a container, wherein the bag filter is the reverse of the bag filter according to any one of the first to third aspects. It is characterized in that a washing device is provided.

With such a configuration, the gas treatment device has a bag filter backwashing device including the inert gas supply means according to claim 1, and a bag filter including the steam supply means according to claim 2. Either the backwashing device or the backwashing device for the bag filter having the gas return flow path is provided, so that the backwashing of the bag filter does not cause ignition of the gasified gas.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. In addition, 3 described below
The gas treatment device (1a, 1b, 1c) of one embodiment is
The configuration will be described as an apparatus for processing gasified gas. The gasification gas referred to here is a fuel gas generated by partial combustion or heating of waste or the like.

[First Embodiment] FIG. 1 is a schematic block diagram for explaining the structure and function of a gas treatment apparatus 1a according to the first embodiment. In the figure, reference numeral 2 is a container, 6 is a bag filter, 11 is a wet gas cleaning device (hereinafter referred to as “gas cleaning device”), 12 is a gas compressor, and 13 is a gas compressor.
Is a gas holder, 20a is a backwash device for the bag filter 6,
Reference numeral 1 is a backwash flow path, 23 is an inert gas supply means, and T is soot and dust.

In the container 2, a gas suction pipe 3 for taking in the gasified gas and a gas delivery pipe 4 for delivering the taken-in gas to the gas cleaning device 11 are connected to the upper and lower sides with a bag filter 6 described later in between. Is provided. Also,
The bag filter 6 is housed inside the container 2,
A soot / dust discharging device 5 is provided at a lower portion of the container 2 located below the bag filter 6. Bug filter 6
It is composed of the filter cloth 6a, and contains the dust T in the gasification gas,
It has a function of removing acidic gases such as HCL (hydrogen chloride) and SOx (sulfur oxide).

The backwash device 20a for the bag filter 6 comprises an inert gas supply means 23, a backwash flow passage 21 connecting the inert gas supply means 23 to the container 2, and a backwash air control means for controlling the spray of backwash air. At least the wash control valve 26 is provided. The inert gas supply means 23 refers to, for example, a PSA gas generator, a vaporization facility that vaporizes an inert gas such as liquid nitrogen or liquefied carbon dioxide, and the like by being connected to the backwash flow passage 21. An inert gas is supplied into the container 2. The discharge pressure of the inert gas supplied into the container 2 is 0.1 MPa to 0.3 M.
It is Pa. The backwash flow passage 21 is a pipe for guiding the inert gas sent from the inert gas supply means 23 to the container 2, and is branched into a plurality of parts on the upper side of the container 2 in accordance with the arrangement of the bag filter 6 in the container 2. Connected.

The wet gas cleaning device 11 has a function of introducing the gasified gas delivered from the container 2 into the interior and purifying it. The gas cleaning device 11 is provided on the downstream side of the container 2 by being connected to the gas delivery pipe 4. Further, a gas compressor 12 and a gas holder 13 are sequentially installed on the further downstream side of the gas cleaning device 11 in the flow of the gasification gas.

Next, the flow of the gasification gas will be described. The gasification gas generated in the combustion furnace, etc.
To be supplied to the container 2. The gasified gas supplied into the container 2 passes through the filter cloth 6a of the bag filter 6 when flowing from the lower side to the upper side in the figure, and is gas washed from the gas delivery pipe 4 connected to the upper side of the container 2. Sent to device 11. When the gasified gas passes through the filter cloth 6a, the dust T or the like in the gasified gas adheres to the dust collecting surface (the lower surface in the figure). As a result, the gasified gas is sent to the gas cleaning device 11 in a state where dust is removed.

The operation of the backwash device 20a will be described.
The inert gas sent from the inert gas supply means 23 is
Pulse is sprayed from the upper part of the container 2 through the backwash flow passage 21. The pulse-sprayed inert gas flows from the clean side (the back side of the dust collecting surface) of the filter cloth 6a toward the dust collecting surface side, and in the process of passing through, it removes the adhered substances such as the dust T. . Then, the adhered substances such as the dust T that have been blown off fall to the lower part of the container 2 and are discarded to the outside of the container 2 by the dust discharge device 5.

The inert gas used for backwashing is mixed with the gasification gas introduced from the gas suction pipe 3 in the container 2, and again passes through the filter cloth 6a and is sent to the gas washing device 11. At this time, the inert gas does not cause ignition of the gasified gas.

The backwash device 20a of this embodiment described above
According to this, ignition of gasification gas in backwashing the bag filter 6 is avoided, and the bag filter 6 is improved in reliability.
It is possible to realize the backwashing device 20a and the gas treatment device 1a including the backwashing device 20a.

[Second Embodiment] Next, a gas processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic configuration diagram illustrating the configuration and function of the gas treatment device 1b according to this embodiment. In the figure, reference numeral 20b indicates a backwashing device provided with the steam supply means 24. In addition, regarding other configurations,
Since it is the same as the embodiment described above, the same reference numerals are used and the description thereof is omitted.

The backwash device 20b for the bag filter 6 comprises a backwash passage 21 and a steam supply means 24 connected to the backwash passage 21. Water vapor supply means 24
Refers to a boiler or the like that generates steam, and it is also possible to generate steam by using a heat source when generating gasification gas.

The water vapor sent from the water vapor supply means 24 is conducted through the backwash flow passage 21 and pulse sprayed from the upper part of the container 2. The pulse-sprayed water vapor flows from the clean side (the back side of the dust collecting surface) of the filter cloth 6a toward the dust collecting surface side, and in the process of passing through, the dust such as the dust T is wiped off. Then, the adhered substances such as the dust T that have been blown off fall to the lower part of the container 2 and are discarded to the outside of the container 2 by the dust discharge device 5.

The water vapor used for the backwash is the gas suction pipe 3
It is mixed with the gasified gas introduced from the inside of the container 2 and again passed through the filter cloth 6a and sent to the gas cleaning device 11. At this time, the water vapor does not cause ignition of the gasified gas.

The mixed gas (gasification gas and water vapor) mixed in the container 2 is delivered from the container 2 and introduced into the wet gas cleaning device 11. When this mixed gas flows into the gas cleaning device 11, it is condensed by the cooling action of the gas cleaning device 11 and becomes water, which is removed from the gasification gas. Therefore, the gasification gas is not diluted with the water vapor used for backwashing the bag filter 6 and is sent from the gas compressor 12 to the gas holder 13 and further to the supply destination of the gasification gas while maintaining the calorific value. Will be done.

The backwash device 20b of this embodiment described above
According to the above, it is possible to realize the backwashing device 20b for the bag filter 6 and the gas processing device 1b provided with the backwashing device 20b, in which the gasification gas is not ignited by the backwashing of the bag filter 6 and the reliability is improved. You can Further, the steam used for backwashing can be easily recovered, and it becomes possible to supply a high-quality gasified gas whose calorific value is maintained without diluting the gasified gas.

[Third Embodiment] Next, a gas processing apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic configuration diagram illustrating the configuration and function of the gas treatment device 1c in this embodiment. In the figure, reference numeral 20c indicates a backwashing device provided with the gas return passage 25. Since the other configurations are similar to those of the first or second embodiment, the same reference numerals are used and the description thereof is omitted.

The gas return passage 25 connects the gas holder 13 and the container 2 and plays a role of returning a part of the gasified gas in the gas holder 13 to the container 2 again. The gasification gas in the gas holder 13 is 0.5 to 1M by the gas compressor 12.
It is stored in a state of being pressurized to Pa and is higher than the pressure inside the container 2. In addition, the gas return passage 25 is
It is branched into a plurality on the connection side with the container 2.

The gasification gas that has been conducted through the gas return flow path 25 and guided to the container 2 is pulse-atomized on the clean side (the back side with respect to the dust collecting surface) of the filter cloth 6a of the bag filter 6,
Adhesive substances such as soot dust T adhering to the dust collecting surface of the filter cloth 6a are wiped off. Then, the gasified gas after the backwashing of the bag filter 6 merges with the gasified gas introduced into the container 2 from the gas suction pipe 3, passes through the filter cloth 6a again, and further passes through the gas cleaning device 11 and further. The gas is compressed by the gas compressor 12 and sent to the gas holder 13.

The backwash device 20c of this embodiment described above
According to this, the ignition of the gasified gas due to the backwashing of the bag filter 6 is avoided, and the backwashing device 20c of the bag filter 6 and the gas processing device 1c including the same which have improved reliability can be realized. Further, by using a part of the gasified gas from the pressurized gas holder 13, it is not necessary to newly provide a gas supply means for backwashing, equipment such as a compressor, and the equipment cost can be reduced. Becomes Also,
Since the gas used for backwashing is the gasified gas, the gasified gas sent from the gas treatment device 1c is not diluted,
It is possible to treat the gasified gas without reducing the heat generation amount.

In the three embodiments described above,
Although the dust removal of the gasified gas containing combustible components and the backwashing of the bag filter 6 have been described, it is also possible to use a similar configuration for the exhaust gas treatment device discharged from the combustion furnace. According to this, backwashing of the bag filter 6 can be performed while safely and appropriately removing the dust T and the like from the exhaust gas with a relatively high risk of ignition.

[0039]

The bag filter backwashing apparatus of the present invention and the gas treatment apparatus including the same have the following effects. In the invention according to claim 1, since the inert gas supply means for ejecting the inert gas is provided on the back surface side of the dust collecting surface of the bag filter, ignition of the gasified gas due to backwashing of the bag filter is avoided. Therefore, the reliability in backwashing can be improved.

According to the second aspect of the present invention, the back side of the bag filter with respect to the dust collecting surface is provided with the water vapor supply means for injecting water vapor. Therefore, backwashing of the bag filter avoids ignition of the gasified gas. . In addition, since steam can be easily removed from the gasification gas as water,
The calorific value of the gasification gas can be maintained without diluting the gasification gas.

The invention according to claim 3 is provided with a gas return flow path for ejecting a part of the gasified gas that has passed through the bag filter to the back surface side with respect to the dust collecting surface of the bag filter. Ignition of gasification gas by washing is avoided. Further, since the backwashing device can be easily configured by providing the gas return flow path, the equipment cost can be reduced. In addition, since the gasified gas is used for backwashing, the gasified gas sent from the gas treatment device is not diluted, and it is possible to supply high-quality gasified gas without reducing the calorific value of the gasified gas. .

According to a fourth aspect of the present invention, since the gas treatment device for filtering the gasified gas is provided with the bag filter backwashing device according to any one of the first to third aspects, It is possible to realize a gas treatment device in which ignition of gasified gas due to backwashing of a bag filter is avoided and reliability is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration and a mechanism of a gas treatment device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a configuration and a mechanism of a gas treatment device according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram illustrating a configuration and a mechanism of a gas treatment device according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram illustrating the configuration and function of a conventional gas treatment device.

[Explanation of symbols]

1a, 1b, 1c gas treatment equipment 2 containers 3 gas suction pipe 3 4 gas delivery pipe 4 5 Dust emission device 6 Bug filter 6a filter cloth 11 Wet gas scrubber 12 gas compressor 13 Gas holder 20a, 20b, 20c Backwash device 21 Backwash channel 23 Inert gas supply means 24 Steam supply device 25 gas return channel 26 Backwash control valve T soot

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Kaihara             12 Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries             Yokohama Co., Ltd. (72) Inventor Hirotoshi Horizoe             12 Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries             Yokohama Co., Ltd. F-term (reference) 4D058 JA04 MA15 MA60 SA20 TA10                       UA10 UA11

Claims (4)

[Claims] 1. A backwashing device for a bag filter, which removes dust collected by passing a gasified gas through the bag filter, wherein an inert gas is jetted to the back surface side of the dust collecting surface of the bag filter. A bag filter backwashing device comprising an active gas supply means. 2. A backwashing device for a bag filter, which removes adhered substances collected by passing a gasified gas through the bag filter, wherein the water vapor supply means for ejecting water vapor to the back surface side of the dust collecting surface of the bag filter. A backwash device for a bag filter, which is provided with. 3. A backwashing apparatus for a bag filter for removing adhered matter collected by passing a gasified gas through the bag filter, wherein a part of the gas passing through the bag filter is collected by the bag filter. A backwash device for a bag filter, which is provided with a gas return flow path for ejecting the gas on the back surface side with respect to the surface. 4. A gas processing device for filtering a gasified gas with a bag filter provided in a container, wherein the bag filter backwashing device according to claim 1 is provided. A gas treatment device characterized by the above.