JP2007263514A - Blocking situation monitoring system and blocking situation determining method for flue in melting furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blocking situation monitoring system for a flue in a melting furnace, which prevents unforseen flue blocking, and eliminates unnecessary cleaning work of the flue. <P>SOLUTION: In the blocking situation monitoring method for the flue 30, a melting furnace 21 interior is made into a negative pressure state by sucking exhaust gas generated in the melting furnace 21 handling assorted solid waste by an exhaust gas blower, a differential pressure detecting means is installed in the flue 30 guiding exhaust gas to an exhaust gas treatment device 29 for detecting a differential pressure between an upstream side of a melting furnace 21 outlet vicinity and a downstream side of a filter 27 vicinity in the flue 30, and an alarm means is provided for indicating malfunction when the differential pressure detected by the differential pressure detecting means reaches a predetermined value. The differential pressure detected by the differential pressure detecting means is compared with a set predetermined value, detection operation is continued if it is smaller than the predetermined value, and if it is the predetermined value or more, an alarm signal is issued to the alarm means, and a manager is informed that it is cleaning time by lighting of a lamp or the like by the alarm means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for detecting the cleaning time of flue pipes in a melting furnace for miscellaneous solid waste.

  Of the low-level radioactive waste generated at nuclear power plants, miscellaneous solid waste is packed in drums, filled with mortar and other fillers, and disposed of in a predetermined burial site. Therefore, it is preferable to reduce the volume of miscellaneous solid waste and reduce the number of embedded drums. Therefore, as a method for reducing the volume of miscellaneous solid waste, for example, a melting volume reduction facility using a high frequency induction heating method has been introduced.

  Specifically, the melting and volume reducing equipment melts and reduces solid solid waste in a canister set in a melting furnace, solidifies it, and then packs the canister together with a drum can to put solidified material such as mortar. The waste is filled.

  In the vicinity of the upper part of the melting furnace, an exhaust exhaust flue is opened, and a flue pipe is connected to the flue, and this flue pipe is connected to an exhaust gas blower and an exhaust treatment device through a filter. Yes. The exhaust gas blower suction operation always keeps the inside of the furnace at a negative pressure to prevent external diffusion of the exhaust gas. The exhaust gas sucked by the exhaust gas blower filters the dust in the exhaust gas through a filter and passes through the exhaust treatment device and is harmless. Is released into the atmosphere.

  However, the exhaust generated in the melting furnace is cooled in the flue piping near the flue outlet of the melting furnace, and as a result, some of the gaseous metal components in the exhaust solidify and adhere to the inner surface of the flue pipe. Then, the flue pipe is closed.

  From the viewpoint of confining the exhaust in the furnace, the inside of the melting furnace is always managed to be negative pressure, but when the flue pipe blockage progresses, it becomes difficult to maintain the negative pressure in the melting furnace. There was a point.

  In addition, since the types of miscellaneous solid waste constituting the melting object are different each time, depending on the melting object, the flue pipe may be blocked in a short period of time, or conversely, it may not be blocked at all for a long time. . Therefore, empirically, periodic cleaning work is performed once every 10 days, but there are cases where there are few deposits and cleaning work is not necessary, and the melting furnace must be stopped for two days when the cleaning work is performed. However, there was a problem that the operating rate of the melting furnace was lowered.

  By the way, in the initial state of the flue pipe blockage, the applicant of the present invention has almost no pressure difference between the upstream side near the melting furnace outlet and the downstream side near the filter in the flue pipe. The knowledge that the difference becomes large was obtained.

  Accordingly, the present invention has been made in view of the above problems, and this pressure difference is constantly measured to monitor the state of blockage of the flue pipe, to prevent inadvertent flue blockage, and unnecessary. It is possible to eliminate a cleaning work, and thus provide a blockage state monitoring system and a blockage state determination method for a flue pipe in a melting furnace that improve the operating rate of a melting facility.

  In the melting furnace according to the present invention, which solves the above problems, the flue pipe blockage monitoring system is configured so that the exhaust generated from the waste processing melting furnace is brought into a negative pressure state in the melting furnace by suction means such as an exhaust gas blower. A flue pipe that leads to the equipment, a differential pressure detecting means for detecting a differential pressure between the upstream side near the outlet of the melting furnace and the downstream side near the filter in the flue pipe, and a difference detected by the differential pressure detecting means An alarm means for indicating an abnormality when the pressure reaches a predetermined set value is provided (first invention).

  According to a second aspect of the present invention, in the method for determining a blockage state of a flue pipe in a melting furnace, the differential pressure detected by the differential pressure detection means reaches a predetermined set value by using the blockage state monitoring system of the first invention. Then, it is determined that the flue pipe is blocked.

  According to the present invention, when the pressure difference between the upstream side near the outlet of the melting furnace in the flue pipe and the downstream side near the filter reaches a predetermined value, an unexpected flue blockage is detected in order to determine the timing for cleaning the flue pipe. Therefore, it is possible to improve the operating rate of the melting facility by eliminating unnecessary cleaning work of the flue pipe.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a radioactive waste treatment facility in the present embodiment. The miscellaneous solid waste melting facility includes a pretreatment facility 1 for sorting miscellaneous solid waste, a melting facility 2 for melting fusible waste among the sorted miscellaneous solid waste, and a post-melting end It consists of a mortar solidification facility 3 in which a drum can containing molten waste is filled with mortar to obtain a solidified solid body, and a storage facility 4 for temporarily storing the solidified solidified body.

  In the pretreatment facility 1, miscellaneous solid wastes of low-level radioactive wastes with different types of properties (materials, dimensions, shapes, etc.) generated in nuclear power generation facilities are unprocessed wastes 6, direct packing 7 The molten object 8 is divided into three sections.

  The object to be melted 8 separated in the pretreatment facility 1 is a non-combustible material such as metals such as carbon steel and stainless steel, concrete, heat insulating material, and glass inorganic materials that can be reduced in volume by melting. It is stored in the charging container 11 or the canister 12 by the storage means 13 such as work or a conveyor, and is carried out to the melting facility 2 by the carrying-out means 14 such as a crane or a conveyor.

  FIG. 2 is a diagram showing a melting facility equipped with a blockage monitoring system in the present embodiment. As shown in FIG. 2, the melting facility 2 has a cylindrical shape, a melting furnace 21 in which a high-frequency induction coil 20 is spirally wound around a lower portion of the inner surface, and initial loading from the lower side of the melting furnace 21. The canister 12 previously packed with the object to be melted 8 is raised, loaded into the high-frequency induction coil 20, the canister 12 is lowered after melting, and moved to the cooling device 22, and the initially loaded melting When the object 8 is melted and reduced in volume, there is room in the canister 12, so the melting object 8 is lowered from the upper side of the melting furnace 21, and the lower gate is opened to open the canister 12. A charging device 24 for charging the object 8 to be melted, a monitoring camera 25 for constantly monitoring the melting state inside the canister 12, a flue 26 for discharging exhaust gas generated from the melting furnace 21, A filter 27 that filters dust in the air, an exhaust gas blower that sucks exhaust gas, an exhaust treatment device 29 that renders the exhaust gas sucked by the exhaust gas blower harmless, and an upstream side of the flue pipe 30 near the outlet of the melting furnace 21 Differential pressure detection means for detecting a differential pressure with the downstream side in the vicinity of the filter 27, and alarm means for indicating an abnormality when the differential pressure detected by the differential pressure detection means reaches a predetermined value.

  The inside of the melting furnace is always kept at a negative pressure by the suction operation of the exhaust gas blower to prevent the external diffusion of the exhaust gas. Then, after the dust in the exhaust gas is filtered by the filter 27, the exhaust gas is rendered harmless by passing through the exhaust gas processing device 29, and then released into the atmosphere.

  The differential pressure detection means is installed in the monitoring control room 100 and pressure sensors 38 and 39 respectively installed on the upstream side near the outlet of the melting furnace 21 and the downstream side near the filter 27 in the flue pipe 30. The A / D converters 101 and 102 for converting the detected values E1 and E2 of the pressure sensors 38 and 39 into pressure data P1 and P2, respectively, and the pressure data P1 and P2 are displayed, and at the same time, the differential pressure between the pressure data P1 and P2. | P1-P2 | is calculated, and this differential pressure is compared with a predetermined value (1.2 KPa in the present embodiment). If it is smaller than the predetermined value, the detection operation is continued. And a PC that emits alarm means.

  When the blockage proceeds in the flue pipe 30 to some extent, the negative pressure in the melting furnace 21 rapidly decreases, and when the pressure difference between the pressure data P1 and P2 becomes 1.2 KPa or more, the blockage rapidly proceeds.

  An alarm means for receiving an alarm signal from the PC receives an alarm signal issued from the PC when the differential pressure reaches a predetermined value, for example, an alarm such as “high melting furnace outlet differential pressure”, lighting of a lamp, etc. Is provided with an alarm output unit 103 that informs the administrator that it is time for cleaning.

  The exhaust gas blower is operated to maintain the negative pressure of the melting furnace 21 at minus 2 KPa, and pressure sensors 38 respectively installed on the upstream side near the outlet of the melting furnace 21 and the downstream side near the filter 27 in the flue pipe 30. The pressure difference between the pressure sensor 39 and the pressure sensor 39 is usually 0.2 to 1.0 KPa.

  In the present embodiment, the method of issuing an alarm slightly before the state of complete occlusion has been shown, but a method of issuing an alarm in stages according to the differential pressure is also possible, and after the alarm is issued It is also possible to incorporate a means for automatically stopping the operation of the melting furnace.

It is a figure which shows the whole structure of the radioactive waste processing equipment in this embodiment. It is a figure which shows the fusion equipment provided with the obstruction | occlusion status monitoring system in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pretreatment equipment 2 Melting equipment 3 Mortar solidification equipment 4 Storage equipment 5 Miscellaneous solid waste 6 Unprocessed waste 7 Direct filling 8 Melting target 11 Input container 12 Canister 13 Storage means 14 Unloading means 20 High frequency induction coil 21 Melting Furnace 22 Cooling device 23 Moving device 24 Input device 25 Monitoring camera 26 Flue 27 Filter 29 Exhaust processing device 30 Flue piping 32 Drum can 38, 39 Pressure sensor 100 Monitoring control room 101, 102 A / D converter 103 Alarm output unit E1 , E2 Detected value P1, P2 Pressure data

Claims (2)

A flue pipe that sucks exhaust generated in a melting furnace for treating waste by suction means such as an exhaust gas blower to bring the inside of the melting furnace into a negative pressure state and leads to an exhaust treatment device,
Differential pressure detecting means for detecting a differential pressure between the upstream side near the melting furnace outlet in the flue pipe and the downstream side near the filter;
A system for monitoring clogging of a flue pipe in a melting furnace, comprising alarm means for indicating an abnormality when the differential pressure detected by the differential pressure detection means reaches a predetermined value. In the melting furnace characterized by using the blockage condition monitoring system according to claim 1 to determine that the flue pipe is blocked when the differential pressure detected by the differential pressure detection means reaches a predetermined value. Method for determining the blockage status of flue piping.

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