JPH062209B2 - Backwash method of dust remover and dust remover - Google Patents

Description

Description: (Industrial field of application) The present invention relates to a dust remover for removing dust contained in exhaust gas, particularly high temperature exhaust gas, by backwashing compressed gas with dust accumulated on a ceramic filter. The present invention relates to a method for backwashing a dust remover and an apparatus therefor.

(Prior Art) When incinerating radioactive waste in a nuclear power plant or the like, it is necessary to efficiently capture and remove dust in high temperature exhaust gas. Particularly, in the incineration of harmful substances such as radioactive wastes and pollutants, special consideration is required to prevent radioactive dust from leaking to the outside.

FIG. 3 is a schematic diagram showing a dust remover for high-temperature exhaust gas after incineration.

An inner surface of a hermetically sealed container 13 made of a steel plate or the like having an exhaust gas inlet 10 on the lower side wall and an exhaust gas outlet 11 on the upper side wall, and a dust outlet 12 at the bottom, preferably refractory brick or amorphous refractory A can body (15) is formed by protecting it with a refractory material (14).

Then, in the can body 15, a filter support board 17 made of heat-resistant steel, refractory material, or the like, preferably having a protruding curved surface on the high temperature side and having a large number of through holes 16, is provided, and the inside of the can body 15 is an exhaust gas inlet. An exhaust gas introduction chamber 18 having an opening 10 and an exhaust gas discharge chamber 19 having an exhaust gas outlet 11 are separated.

Then, the bottomed cylindrical porous ceramic filter 20 is inserted into the many through holes 16 of the filter support board 17 and suspended in the exhaust gas introducing chamber 18. In this case, it is preferable that an annular enlarged portion 22 is provided on the outer periphery of the open end 21 of the ceramic filter 20, and the annular enlarged portion 22 is brought into contact with the filter support board 17 to be kept airtight. Then, in the exhaust gas discharge chamber 19 on the open end 21 of each ceramic filter 20, a backwash air injection nozzle 23 that opens in the direction of the hollow portion 20a inside the cylinder of each ceramic filter 20 is provided.
The backwash air injection nozzle 23 is connected to an air supply conduit 24, and the air supply conduit 24 further includes the backwash air injection nozzle.
It is connected to a compressed air supply device 25 for supplying compressed air to 23.

The can body 15 is hermetically held by a lid body 26 which is a separate body. For example, when the high-temperature combustion exhaust gas is introduced into the exhaust gas introduction chamber 18 through the exhaust gas introduction port 10 as shown by the arrow A, the gas flow passes through the pores of many ceramic filters 20 suspended by the filter support board 17. The dust or the like contained in the exhaust gas is removed by the ceramic filter 20, and the clean high-temperature exhaust gas from which the dust or the like is removed passes through the open end 21 from the hollow portion 20a in the cylinder of the ceramic filter 20 into the exhaust gas discharge chamber 19. The gas enters and is discharged from the gas inlet 11 as indicated by arrow B.

When dust accumulates on the surface of the ceramic filter 20 due to long-time operation, compressed air is supplied from the compressed air supply device 25 to the backwash air injection nozzle 23 through the air supply conduit 24, and the compressed air is supplied to the hollow portion 20a in the cylinder. Make a shocking injection into. Then, the dust and the like accumulated on the outer surface of the ceramic filter 20 is blown away by the compressed air and scattered, and falls downward to be taken out from the dust outlet 12.

(Problems to be Solved by the Invention) However, in such a dust remover, the combustion exhaust gas is continuously supplied into the can body 15 when the incinerator is continuously operated. For this reason, if the dust removal of the ceramic filter 20 is performed at the same time during operation, the processing of the exhaust gas is stopped, and the pressure in the exhaust gas introduction chamber 18 is temporarily increased extremely, which is a disadvantage. Stopping and removing dust. In particular, when removing dust from combustion exhaust gas from harmful substances such as radioactive waste, it is necessary to reduce the pressure inside the incinerator and the inside of the can to keep the negative pressure against the atmosphere so that the harmful substances do not leak outside the can. . In this case, many ceramic filters 20 at a time.
If more compressed air is blown out, the pressure rises rapidly in a short time and the negative pressure cannot be maintained, which is inconvenient.

An object of the present invention is to provide a method and apparatus for backwashing a dust remover, which can remove dust accumulated on a bottomed cylindrical ceramic filter at any time during operation and enhance dust treatment efficiency.

(Means for Solving the Problems) According to the present invention, a filter support member having a plurality of through holes is attached to a can body, and the can body is divided into an exhaust gas introducing chamber and an exhaust gas discharging chamber, and the plurality of through holes are provided. The bottomed cylindrical ceramic filter is inserted and fixed to each of the above, the opening of the bottomed cylindrical ceramic filter is located on the side of the exhaust gas discharge chamber, and the dust in the radioactive substance combustion exhaust gas introduced into the exhaust gas introduction chamber is described above. Removed with a bottomed cylindrical ceramic filter, exhaust the exhaust gas that has passed through the bottomed cylindrical ceramic filter from the exhaust gas discharge chamber, through the opening from a plurality of gas injection means provided in the exhaust gas discharge chamber Gas is injected into the hollow part of the bottomed cylindrical ceramic filter to remove and scatter the dust accumulated on the bottomed cylindrical ceramic filter. In the backwashing method of the dust remover, when performing backwashing while continuously supplying the exhaust gas into the exhaust gas introduction chamber, a part of the gas in the first compressed gas supply tank is used as gas injection means. By selectively supplying to the plurality of bottomed cylindrical ceramic filters, the scattering removal treatment is sequentially performed, and the exhaust gas is continuously supplied into the exhaust gas introduction chamber, and backwashing is performed. When not present, gas is supplied to all of the gas injecting means, thereby cooling the gas injecting means, and when the supply of the exhaust gas is stopped, the capacity is larger than that of the first compressed gas supply tank. Of the plurality of bottomed cylindrical ceramic filters are sequentially performed by selectively supplying the gas in the second compressed gas supply tank having a large size to a part of the gas injecting means. Wherein, it relates to a backwash method of dust remover.

The present invention also provides a can body; a filter support member that is mounted in the can body and divides the can body into an exhaust gas introduction chamber and an exhaust gas discharge chamber; and a plurality of through holes of the filter support member. Inserted and fixed, the opening side is located on the side of the exhaust gas discharge chamber, a plurality of exhaust gas to remove dusts in the exhaust gas introduced into the exhaust gas introduction chamber and exhaust the passing exhaust gas to the exhaust gas discharge chamber through the opening A cylindrical ceramic filter with a bottom; a gas injection port provided in the exhaust gas discharge chamber and facing a hollow portion inside the cylinder of the cylindrical ceramic filter with a bottom, and the cylinder from the gas injection port through the opening. In a dust remover having a plurality of gas injection means for injecting gas into the inner hollow portion, a first compressed gas supply tank and a second compressed gas supply tank having a larger capacity than the first compressed gas supply tank. A compressed gas supply tank, a compressed gas supply pump for supplying the gas to the first compressed gas supply tank and the second compressed gas supply tank, and the plurality of gas injection means with the gas, respectively. A gas communication path for supplying the gas, and a valve for selectively performing supply and cutoff of the gas in each gas communication path, and a part of the gas in the first compressed gas supply tank It is configured so that it can be selectively supplied to the injection means, and is configured to be able to selectively supply the gas in the second compressed gas supply tank to a part of the gas injection means, and The present invention relates to a dust remover configured so that gas can be supplied from the compressed gas supply pump to all of the gas injecting means.

(Embodiment) FIG. 1 is a schematic view showing a dust remover with a backwash device according to this embodiment. The same functional members as those in the apparatus of FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

A feature of this example is that the electromagnetic valve 1 is provided for each of the injection nozzles 23 in the air communication pipe 8 connected to each of the injection nozzles 23. And compressed air supply pump
An electromagnetic valve 5 is provided between 30 and the compressed air tank 2, and an electromagnetic valve 4 is also provided between the small capacity first compressed air tank 2 and the large capacity second compressed air tank 3. An electromagnetic valve 6 is also provided between the compressed air supply pump 30 and the air communication pipe at the outlet of the first compressed air tank 2.

Then, while supplying the exhaust gas from the incinerator (not shown) into the exhaust gas supply chamber 18, the electromagnetic valve 5 is opened and the compressed air supply pump 30 sends the air to the compressed air tank 2 as shown by an arrow D. At this time, the solenoid valves 4, 1 and 7 are closed to shut off the air. Next, for example, in the drawing, only the solenoid valve 1 of the left end air passage tube 8 provided above the opening of the left end ceramic filter 20 is opened, and the air injection port is opened.
The air in the compressed air tank 2 with a smaller capacity than 23a is jetted (for example, 5 kg / cm ² × 10), and the ceramic filter 20
Scatter and remove dust. Next, the solenoid valve 1 is closed to shut off the air, compressed air is stored again in the pressurized seed air tank 2, and the solenoid valve 1 of the air passage pipe 8 connected to the second injection nozzle 23 from the left end in the drawing is closed. Open, 2 from the left end
The dust of the second ceramic filter 20 is scattered and removed.
Next, the same process is performed on the third ceramic filter 20 from the left end. In this way, the opening and closing of the corresponding solenoid valve 1 for each ceramic filter 20 are performed sequentially or sequentially, and dust is scattered and removed for each ceramic filter 20.

When the scattering and removal of dust is completed for each ceramic filter 20, the solenoid valve 7 and all solenoid valves 1 are opened. The solenoid valve 5 is closed. Then, a small amount of air is sent through the solenoid valve 7 and the flow rate adjusting needle valve 6 as shown by arrow E, and all the ceramic filters are passed through each solenoid valve 1.
Air is fed into the hollow portion 20a in the cylinder 20. The passing amount of air is adjusted to a minute amount by the flow rate adjusting needle valve 6 (for example, 0.1 m ³ / h · piece).

Further, the solenoid valves 7 and 1 are closed, the solenoid valves 5 and 4 are opened, compressed air is sent to the large capacity compressed air tank 3 as shown by an arrow H, and the solenoid valve 5 is closed to store compressed air. To do. Next, when the operation of the incinerator is stopped, with the solenoid valves 5 and 7 closed, either the solenoid valve 4 or the solenoid valve 1 is opened, and compressed air is injected into the cylindrical hollow portion 20a of the ceramic filter 20. (For example, 5 kg / cm ² × 50) to remove dust more effectively by scattering.

The following effects can be obtained by the device of this example.

(a). Air is stored in the compressed air tank 2, and dust is scattered and removed sequentially for each ceramic filter 20.
Therefore, unlike the case of injecting the compressed air to all the ceramic filters 20 at the same time, since the pressure seed air is injected for each one, the pressure in the exhaust gas introduction chamber 18 does not rise so much, and the exhaust gas is distributed. Exhaust gas dust removal can be continued through the other ceramic filters 20 without any influence. Therefore, the dust removal of the ceramic filter 20 can be sequentially performed while continuing the operation, so that the dust removal efficiency of each ceramic filter 20 can be maintained well even during the continuous operation, and the ceramic filter 20 can be clogged even when continuously operated for a long time. Can be prevented.

In particular, at the time of incineration of radioactive waste, it is necessary to maintain the inside of the can body 15 at a negative pressure (for example, −200 mmAq), but in this example, compressed air is stored in the small capacity air tank 2,
Since this air is sprayed only for each ceramic filter or for each ceramic filter (see FIG. 2 described later), there is no possibility that the pressure in the can body 15 rises and harmful substances leak to the outside. Moreover, the processing of the combustion exhaust gas is not temporarily interrupted.

(b). During normal operation, a small amount of air is simultaneously made to flow to each ceramic filter 20 through the flow rate adjusting needle valve 6. Since each backwash air injection nozzle heated by the combustion exhaust gas is appropriately cooled by this small amount of air, the danger that the air conduit 8 outside the can body 15 is heated by heat transfer and the operator is burned can do.

(c). In a radioactive waste incinerator or the like, since the introduction of exhaust gas is stopped when the operation is stopped, a negative pressure of, for example, about -1000 mmAg is obtained. However, in the conventional backwashing apparatus as shown in FIG. 3, air is jetted from all the air jetting nozzles at a time, so if the amount of air per nozzle is increased and the purging effect is enhanced, the total amount of air is reduced. Since the amount of air injected becomes very large and the pressure inside the can 15 becomes a positive pressure, and radioactive waste leaks to the outside, effective purging was difficult even when the operation was stopped.

On the other hand, in this example, the incinerator is stopped, and the negative pressure in the can body 15 is kept higher than during operation, while the large-capacity compressed air tank 3 is used for each air injection nozzle (see FIG. 2 described later). Since a large volume of compressed air is supplied to every four nozzles in the example), the amount of air jetted from each air jet nozzle is much larger than in the conventional case, and the dust scattering removal effect is dramatically enhanced. Moreover,
Since backwashing is performed for every one or several air injection nozzles, the amount of compressed air injected at one time can be kept within an appropriate range as a whole, and there is no fear that the pressure in the can body 15 becomes a positive pressure. There was no such thing, and efficient backwashing was possible even when the operation was stopped.

As described above, the filter support board 17 has a protruding curved surface on the high temperature side, that is, the exhaust gas introduction chamber 18 side,
Very good results are obtained with repeated thermal expansion and contraction, and it is particularly preferable that the convex curved surface shape is exhibited as the exhaust gas temperature becomes higher.

In the above example, one electromagnetic valve is provided for each air injection nozzle, but as shown in FIG. 2, a total of four air injection nozzles 23 are connected to one electromagnetic valve and at the same time. It is also possible to supply compressed air from a small capacity compressed air tank to the four air injection nozzles 23 and perform dust scattering removal on the ceramic filter for every four nozzles. Of course, the number of air injection nozzles connected to one solenoid valve may be further changed.

The above embodiment can be modified in various ways.

In FIG. 1, when the cylindrical ceramic filter having a bottom is airtightly held by the filter support board 17, the annular enlarged portion 22 is used.
It is desirable to interpose a sealing material such as asbestos between the filter support board 17 and the filter support board 17.

Air supply conduit 8 to which each backwash air injection nozzle 23 is connected
1 is installed outside the can body 15 in FIG. 1, but may of course be installed inside the can body 15.

In the example of FIG. 1, the dust is sequentially removed from the leftmost ceramic filter 20 in the drawing, but the order of performing the dust removal can be changed arbitrarily.

The jet gas does not have to be air.

INDUSTRIAL APPLICABILITY The present invention can be applied in the past to high temperature combustion exhaust gas discharged from incinerators for treating radioactive materials, dryers, etc. in addition to incinerators of nuclear power plants, and dust from dry exhaust gas.

(Effect of the Invention) According to the present invention, when backwashing is performed while continuously supplying exhaust gas into the exhaust gas introduction chamber, the gas in the first compressed gas supply tank is partially supplied to the gas injection means. By selectively supplying the above, the scattering removal processing of a plurality of bottomed cylindrical ceramic filters is sequentially performed.

In particular, when incinerating radioactive waste, it is necessary to maintain the inside of the can at a negative pressure, but the compressed gas is stored in a relatively small capacity first gas tank, and this gas is used as a ceramic filter. Since the injection is performed every time or every plural times, there is no possibility that the pressure inside the can rises and the radioactive substance leaks to the outside, and the treatment of combustion exhaust gas is not temporarily interrupted.

Further, when the supply of the exhaust gas is stopped, the gas in the second compressed gas supply tank having a larger capacity than the first compressed gas supply tank is selectively supplied to a part of the gas injection means. The scattering removal processing of the plurality of bottomed cylindrical ceramic filters is sequentially performed.

In the radioactive waste incinerator, since the introduction of the exhaust gas is stopped when the operation is stopped, a negative pressure of, for example, about -1000 mmAg is obtained.

In the present invention, the incinerator is stopped, and the negative pressure in the can is kept higher than during operation, while the gas is selectively supplied from the compressed gas tank having a relatively large capacity. The injection amount is large, and the dust scattering removal effect is dramatically enhanced. Moreover, since the gas is selectively supplied to a part of the gas injection means, the amount of compressed gas injected at one time can be kept within an appropriate range as a whole, and the pressure inside the can becomes a positive pressure. There was no such problem, and efficient backwashing was possible even when the operation was stopped.

Further, the exhaust gas is continuously supplied into the exhaust gas introduction chamber,
Further, when backwashing is not performed, gas is supplied to all of the gas injecting means, and thereby the gas injecting means is cooled, so that each backwashing gas injecting means heated by the combustion exhaust gas is It is appropriately cooled by a trace amount of gas. As a result, it is possible to prevent the risk that the worker is burned because the gas conducting tube outside the can body is heated by heat transfer.

[Brief description of drawings]

FIG. 1 is a schematic partial sectional view of a dust remover with a backwash device, FIG. 2 is an enlarged partial sectional view of an essential part showing another backwash device, and FIG. 3 is a schematic portion showing a conventional dust remover with a backwash device. FIG. 1, 4, 5, 7 ... Solenoid valve 2 ... Small capacity first compressed air tank 3 ... Large capacity second compressed air tank 6 ... Flow control needle valve 8 ... Gas conduit 15 ... Can 18 ... Exhaust gas Introduction chamber 19 ... Exhaust gas exhaust chamber 20 ... Cylindrical ceramic filter with bottom 20a ... Hollow part in cylinder 21 ... Opening 23 ... Gas injection nozzle 23a ... Gas injection port 30 ... Gas supply pump

Claims (2)

[Claims] 1. A filter supporting member having a plurality of through holes is attached to a can body to divide the can body into an exhaust gas introduction chamber and an exhaust gas discharge chamber, and a bottomed cylindrical ceramic is provided in each of the plurality of through holes. The filter is inserted and fixed, the opening of the bottomed cylindrical ceramic filter is located on the side of the exhaust gas discharge chamber, and the dust in the radioactive substance combustion exhaust gas introduced into the exhaust gas introduction chamber is removed by the bottomed cylindrical ceramic filter. Then, the exhaust gas having passed through the bottomed cylindrical ceramic filter is discharged from the exhaust gas discharge chamber, and a plurality of gas injection means provided in the exhaust gas discharge chamber through the openings to form the cylinder of the bottomed cylindrical ceramic filter. In the backwashing method of the dust remover, which injects gas into the inner hollow portion and performs the scattering removal treatment of the dust accumulated on the bottomed cylindrical ceramic filter. When performing backwashing while continuously supplying the exhaust gas into the exhaust gas introduction chamber, selectively supplying the gas in the first compressed gas supply tank to a part of the gas injection means. Thus, the scattering removal treatment of the plurality of bottomed cylindrical ceramic filters is sequentially performed, and the exhaust gas is continuously supplied into the exhaust gas introduction chamber, and when backwashing is not performed, the gas injection unit Of the second compressed gas supply tank having a capacity larger than that of the first compressed gas supply tank when the gas injection unit is cooled by this and the supply of the exhaust gas is stopped. An inverse of a dust remover, characterized in that the scattering removal processing of the plurality of bottomed cylindrical ceramic filters is sequentially performed by selectively supplying the gas in the tank to a part of the gas injecting means. Method. 2. A can body; a filter support member which is mounted in the can body and divides the can body into an exhaust gas introduction chamber and an exhaust gas discharge chamber; inserted into each of a plurality of through holes of the filter support member. Fixed, the opening side is located on the side of the exhaust gas discharge chamber, a plurality of existing for removing dusts in the exhaust gas introduced into the exhaust gas introduction chamber and discharging the passed exhaust gas to the exhaust gas discharge chamber through the opening. A bottom cylindrical ceramic filter; provided in the exhaust gas discharge chamber,
A plurality of gas injecting means for injecting gas from the gas injecting port to the in-cylinder hollow part through the opening, the gas injecting port facing the in-cylinder hollow part of the bottomed cylindrical ceramic filter; In a dust remover having, a first compressed gas supply tank, a second compressed gas supply tank having a larger capacity than the first compressed gas supply tank, the first compressed gas supply tank and the second compression A compressed gas supply pump for supplying the gas to a gas supply tank, a gas conduit for supplying the gas to each of the plurality of gas injecting means, and a supply / cutoff of the gas in each gas conduit. And a valve for selectively performing, and is configured to be able to selectively supply the gas in the first compressed gas supply tank to a part of the gas injection means, and the second Supply of compressed gas It is configured such that the gas in the supply tank can be selectively supplied to some of the gas injecting means, and the gas can be supplied from the compressed gas supply pump to all of the gas injecting means. Is a dust remover.