JPH0474507A - Method and apparatus for renewing filter for waste gas treatment - Google Patents

Abstract

PURPOSE:To make back wash of a filter possible while keeping the inside of the system at negative pressure by closing a valve in an outlet side of a filter apparatus to treat flue gases of an incinerator by a filter element and opening a valve in a relief valve system. CONSTITUTION:A valve 13 in the outlet side of a filter apparatus to treat flue gases of an incinerator 1 by a filter element 8 is closed and valves 10, 11, 14 of a relief valve system are opened, so that the inside pressure is sufficiently decreased as compared with that at normal operation and air for back wash is blown from an air source 5 for back wash. Then, while the system is kept at negative pressure, the filter element 8 is back-washed and dust-containing gas produced at that time is led to a HEPA filter 7 installed in the relief valve system of the incinerator 1. As a result, with no need of two filter apparatuses, back wash of the filter is carried out while the inside of the system is kept at negative pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for regenerating an exhaust gas treatment filter connected to an incinerator for incinerating radioactive waste, for example.

(Prior Art) For example, in the exhaust gas treatment system of an incinerator that incinerates radioactive waste, etc., a filter device in which a number of ceramic filters are attached inside a can body is connected. The inside of these exhaust gas treatment systems, together with the inside of the incinerator, is maintained at a negative pressure to prevent exhaust gas containing radioactive materials from leaking to the outside. However, during use, the filter of such a filter device gradually accumulates dust on its surface and its filtration performance deteriorates, so it is necessary to perform backwashing and regeneration after using it for a predetermined period of time.

Figure 2 is a system diagram of the conventional technology for this purpose.
Two filter devices (2), (2) at the exhaust gas outlet of 1)
are installed in parallel, and one or both filter devices (2
) The structure is such that the gas purified by the exhaust gas blower (3) is guided to the stack (4). When backwashing the filter, the valve on the outlet side of the filter device (2) that performs backwashing is closed, and the dust-containing gas generated by the blowing of backwash air from the backwash air source (5) is removed. By guiding the gas to a filter device (2) in a system other than the filter device for washing, the system is maintained at a negative pressure and the dust-containing gas is filtered. In addition, (6) is an emergency relief valve to release gas when the internal pressure of the incinerator (1) increases, and (7) is a HEPA installed in the tobacco relief valve system.
It's a filter.

However, since such a conventional device requires two filter devices (2) for backwashing, there are problems in that it takes up space, increases equipment cost, and increases the number of maintenance steps.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, eliminates the need for two filter devices, and backwashes the filter while maintaining negative pressure inside the system. The present invention was completed in order to provide a method and apparatus for regenerating an exhaust gas treatment filter that can perform the following steps.

(Means for solving the problem) The above problem is solved by closing the valve on the outlet side of the filter device that processes the exhaust gas of the incinerator using the filter element, and opening the valve of the relief valve system, so that the inside of the incinerator becomes lower than during normal operation. After sufficiently reducing the pressure, backwash air is blown into the system to backwash the filter element while maintaining a negative pressure inside the system, and the dust-containing gas generated at this time is guided to the HEPA filter installed in the incinerator's relief valve system. This problem can be solved by a method for regenerating an exhaust gas treatment filter, which is characterized by:

In addition, the above-mentioned problem is solved by connecting a single filter device that processes the exhaust gas to the incinerator and an exhaust gas blower in series via a valve, as well as providing a backwashing air blowing device to the filter device. A bypass line is attached to the relief valve part of the relief valve system with a HEPA filter installed to release dust-containing gas when blowing air for backwashing.
This problem can be solved by an exhaust gas treatment filter regeneration device characterized in that the outlet side of the HEPA filter is connected to the suction side of the exhaust gas blower.

The present invention will be explained in more detail below with reference to illustrated embodiments.

(Embodiment) Fig. 1 shows an embodiment of the device of the present invention, in which a single filter device ( 2
) and an exhaust gas blower (3) for sucking the purified gas and discharging it to the stack (4) are connected in series. In addition, the filter device (2) is equipped with a backwash air source (5), and the filter element (8) is attached as before.
It is now possible to perform backwashing.

The incinerator (1) is equipped with a relief valve (6) that operates when the pressure inside the incinerator increases, as in the past, and this relief valve system includes an HE for filtering this dust-containing gas.
A PA filter (7) is provided.

The outlet side of the HEPA filter (7) is connected to the stack (4) as in the conventional case, but in the present invention, the outlet side of the HEPA filter (7) is connected to the exhaust gas blower (3).
A path (9) with a valve 0ω connected to the suction side is provided. Also, there is a valve (I) in the relief valve (6) part.
A bypass line 021 with I) is provided.

The inside of the incinerator (1) is maintained at -200 mmAq during normal operation to avoid leakage of radioactive materials to the outside, and the inside of the filter device (2) is maintained at -300 mmAq during normal operation. ing.

(Function) The device configured as described above guides the exhaust gas from the incinerator (1) to the filter device (2), and sucks the purified exhaust gas by the exhaust gas blower (3) through the valve 09 on the outlet side. The stack (4) is discharged to the outside air, but when dust adheres to the surface of the filter (8) of the filter device (2) and filtration resistance increases, backwashing is performed as follows. .

First, close the valve 0 on the outlet side of the filter device (2), then close the valve (11) on the bypass line a and
) in front of the exhaust gas blower (3) and adjust the opening degree of the valve 04) in front of the exhaust gas blower (3).
The pressure inside the filter device (2) is reduced to a pressure sufficiently lower than that during normal operation, for example, to about -1000 mmAq.

In this state, from the backwash air source (5) to the filter device (2)
Blow backwashing air into the inside of the filter element (
8) Backwash. As a result, the dust adhering to the surface is peeled off and the filter niremen l-(8) is regenerated, but the pressure inside the filter device (2) is maintained at a sufficiently low pressure when backwashing starts. Therefore, even when backwashing air is blown, the pressure only increases to, for example, about -500 mmAq, and backwashing can be performed while maintaining the negative pressure in the exhaust gas treatment system. Therefore, there is no risk that radioactive substances will leak from the system into the atmosphere due to the blowing pressure of the backwashing air.

In addition, a large amount of dust-containing gas is generated due to the blowing of air for backwashing, but this gas returns to the incinerator (1) side.
Furthermore, the exhaust gas is sucked by the exhaust gas blower (3) and the relief valve (
6) enters the relief valve system from the bypass line 02).

And the HEPA filter installed in this system (
7) and is filtered, and only the purified gas is discharged to the outside from the tank (4) via the exhaust gas blower (3). When backwashing is completed in this manner, valve 0■ is opened, valve (11) and valve α0) are closed, and normal operation is resumed.

(Effects of the Invention) As explained above, according to the method and device for regenerating an exhaust gas treatment filter of the present invention, two filter devices are not required, and the inside of the system is always maintained at negative pressure. You can backwash the filter. For this reason, the second
Compared to the conventional equipment shown in the figure, it requires less equipment installation space, reduces equipment costs, reduces maintenance effort, and backwashes filters without leaking radioactive materials to the outside. becomes possible.

As described above, the present invention is particularly suitable for use in incinerators for radioactive waste, but it goes without saying that it can also be applied to incinerators for general industrial waste.

Therefore, the present invention greatly contributes to the development of industry as a method and apparatus for regenerating an exhaust gas treatment filter that solves the conventional problems.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram showing an embodiment of the present invention, and FIG. 2 is a piping system diagram showing a conventional example. (1): Incinerator, (2): Filter device, (3): Exhaust gas blower, (6): Relief valve, (7): HE P
A filter, (8): Filter element, 00), (
I+): Valve, 02): Bypass line, 09.0
@:valve.

Claims (1)

[Claims] 1. Filter element (8) for exhaust gas from incinerator (1)
The valve on the outlet side of the filter device (2) processed by
13), and close the relief valve system valves (10) and (11).
), (14) to sufficiently reduce the internal pressure compared to normal operation, and then blow in backwashing air to backwash the filter element (8) while maintaining negative pressure in the system. A method for regenerating a filter for exhaust gas treatment, characterized by guiding dust-containing gas to a HEPA filter (7) provided in a relief valve system of an incinerator (1). 2. The incinerator (1) is equipped with a single filter device (2) and an exhaust gas blower (3) to treat its exhaust gas, and a valve (13)
and a filter device (2) connected in series through
A backwashing air blowing device is installed in the incinerator (1) to release dust-containing gas when backwashing air is blown into the relief valve (6) part of the relief valve system equipped with a HEPA filter (7) installed in the incinerator (1). A bypass line (12) is attached and HEP
A regeneration device for an exhaust gas treatment filter, characterized in that the outlet side of the A filter (7) is connected to the suction side of the exhaust gas blower (3).