JPS59119297A - Radioactive gaseous waste processing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to radioactive gaseous waste treatment equipment used, for example, in nuclear power plants.

[Technical background of the invention]

A conventional example will be explained with reference to FIG. FIG. 1 is a system diagram showing a schematic configuration of a conventional radioactive gas waste processing apparatus. Reference numeral 1 in the figure indicates an air extractor. This air extractor 1 is configured to extract exhaust gas containing oxygen and hydrogen. The exhaust gas extracted by this air extractor 1 is sent to a preheater 2.
will be introduced in The preheater 2 is constituted by, for example, a shell-and-tube type heat exchanger, and is configured to use steam inside the power plant, which is introduced from an oven (not shown), as a heat source.

The exhaust gas introduced into the preheater 2 is heated to a temperature opposite to the recombination reaction and then introduced into the recombiner 3. This recombiner 3 is filled with a catalyst 4, which promotes the recombination reaction between oxygen and hydrogen in the introduced exhaust gas. The exhaust gas from which hydrogen has been removed in the recombiner 3 is introduced into the condenser 5. The exhaust gas is cooled in the condenser 5, and most of the water vapor in the exhaust gas is condensed and removed. Thereafter, the exhaust gas is introduced into the radioactive attenuation removal device 6. The radioactivity attenuation removal device 6 is comprised of a dehumidifying and drying device, a filter, a hold-up device, and the like. The exhaust gas is processed by the radioactivity attenuation removal device 6, and then guided to the exhaust pipe 8 by the vacuum pump 7 and discharged into the atmosphere. An electric heater 9 is provided on the surface of the recombiner 3, and a temperature detector 10 is installed inside the recombiner 3 to detect the temperature inside the recombiner 3. That is, the configuration is such that the lightning heater 9 is controlled via the controller 11 based on the detection signal of the temperature detector 10 to maintain the temperature inside the recombiner 3 at about 150°C to 180°C.

[Problems with background technology]

According to the above-mentioned radioactive gas waste treatment equipment of A.1η configuration,
In particular, the preheater 2 is configured to heat exhaust gas using in-house steam. Further, in order to secure a heat transfer area, a large-sized device is required, and the cost is high and maintenance is difficult at $1 ton. In addition, the response is poor and it may be difficult to control the degree of heating of the exhaust gas depending on the temperature inside the recombiner 3. In addition, as mentioned above, the internal steam from the internal boiler of the power plant is used as a heat source, and for example, even though there is almost nothing else that requires internal steam during plant operation, the internal boiler continues to operate. It has to be done, and it is uneconomical. and recombiner 3
The electric heater 9 installed on the surface of the electric heater 9 maintains its temperature, but if a part of the electric heater 9 is damaged, the temperature distribution becomes uneven. Ta.

[Purpose of the invention]

An object of the present invention is to provide a radioactive gas waste processing apparatus that can reduce costs, improve workability during maintenance, etc., and is easy to control.

[Summary of the invention]

The radioactive gas waste treatment apparatus according to the present invention includes an air extractor that extracts exhaust gas, and a regenerator that houses a catalyst inside and introduces the exhaust gas from the air extractor to recombine oxygen and hydrogen in the exhaust gas. This configuration includes a combiner, a firewood heater provided in the recombiner, and a control mechanism that controls the rotary heater.

In other words, by providing the M heater in the recombiner, the recombiner has an exhaust gas heating function and eliminates the need for a conventional preheater.
Furthermore, by heating the recombiner from inside the container, the recombiner is configured to increase efficiency and reduce costs.

Therefore, various problems when using a preheater can be solved, and costs can be reduced and workability during maintenance etc. can be improved. Since the exhaust gas is heated by the heater, it has good controllability, and since it heats from inside the container of the recombiner, it is highly efficient and does not need to heat the potash container wall more than necessary. Even if the catalyst is damaged, temperature non-uniformity does not occur within the container or on the wall surface of the container, which is extremely effective in maintaining the quality of the catalyst and the container.

[Embodiments of the invention]

A first embodiment of the present invention will be described with reference to FIGS. 2 and 3. Reference numeral 101 in the figure indicates an exhaust gas extractor. This exhaust gas extractor 101 is configured to extract exhaust gas containing sulfuric acid and hydrogen. The exhaust gas extracted from the exhaust gas extractor 10 is introduced into the recombiner 102. This recombiner 102 is filled with a catalyst 103,
There is a component that promotes the recombination reaction between oxygen and hydrogen in the exhaust gas introduced by the catalyst 103. An electric heater 104 is installed inside the recombiner 102. The electric heater 1θ4 is controlled by a control mechanism 1θ5. That is, an exhaust gas inlet temperature detector 106 is installed in the exhaust gas inlet, and a melting medium temperature detector 107 is installed in the catalyst 103 to detect the temperature in the catalyst 10S. The electric heater 104 is controlled via a controller 108 based on detection signals from an exhaust gas inlet temperature detector 106 and a catalyst temperature detector 107.

The exhaust gas from which hydrogen has been removed by the recombination reaction in the recombiner 102 is introduced into the condenser 109, where it is cooled and most of the water vapor in the exhaust gas is condensed and removed. . The exhaust gas is then introduced into a radioactive attenuation removal device 110.

The radioactivity attenuation removal device 110 is comprised of a dehumidifying and drying device, a filter, a hold-up device, and the like. The exhaust gas is processed by the radioactivity attenuation removal device 110, and then guided to the exhaust stack 112 by the vacuum pump 111 and discharged into the atmosphere.

Next, the recombiner 102 will be explained in detail with reference to FIG. Reference numeral 112 in the figure indicates a container body of the recombiner 102. At the bottom of this container body 112 is a gas inlet pipe 1.
13 are connected. A gas inflow pipe 114 is disposed within the container body 112 in communication with the gas inlet pipe 113, and its end is open within the container body 112.

The electric heater 104 is housed within this gas inflow pipe 114 . This electric heater 104 has one end fixed to a lower plate 116 of a heater mounting pipe 115.
Cable 11 installed through heater attachment pipe 115
6A via a terminal 117.

The heater attachment pipe 115 is bolted to the upper end of the container body 112, and a terminal cover 116B is bolted to the upper end thereof. The number of electric heaters (1,040 is planned) is expected to be sufficient in case of a disconnection accident during J rotation, and in the event of a disconnection, the controller 108 is configured to automatically switch to another heater. There are many people. A plurality of baffles 118 having notches on the left and right sides are provided in the gas inflow pipe 114, and the electric heater 1θ4 is provided to pass through the plurality of baffles 11B. Baffle 1 above
18, a zigzag-shaped gas flow path is formed.

In addition, although the electric heater 104 and the baffle 118 have a heater attachment tube 115 fixed to the upper end 7 flange portion 112A, by removing the bolt (not shown), the heater attachment tube 1
15 and can be removed from the container main body 112. Gas inflow pipe 114 and container body 112
A screen stand 119 is provided between the two. The catalyst 10
3 is a catalyst filling port 120 formed in the upper part of the container body 112.
7 is filled on this screen stand 119 via the screen. Further, the catalyst filling port 120 is provided with a removable lid 121. The container body 112 is provided with a gas outlet 122, and the gas that has undergone a recombination reaction within the container body 112 flows out through the gas outlet 122.The temperature of the foreffluent exhaust gas inlet is detected. The container 106 is inserted into the container body 112 by penetrating the upper layer 112B of the container body 112, and the catalyst temperature detector 107 is inserted by penetrating the side wall portion 112C of the container body 112.

According to the above configuration, the exhaust gas extracted by the exhaust gas extractor ioi is introduced into the gas inflow pipe 114 in the container body 112 via the gas inlet 1 pipe 113 of the recombiner 102. Then, the gas flows upward along a zigzag gas flow path formed in the gas inflow pipe 114, and is heated by the electric heater 104 at this time. and gas inflow westill
It flows out into the container body 112 from the upper end opening 114A of the pipe 114 and flows through the catalyst 103 from above to below. At this time, oxygen and hydrogen in the exhaust gas undergo a recombination reaction, and the hydrogen in the exhaust gas is removed. The gas then flows out of the container body 112 through the gas outlet 122 . The exhaust gas that has flowed out of the container body 112 flows into the condenser 109. The exhaust gas is cooled in the condenser 109, and most of the water vapor in the exhaust gas is condensed and removed. The exhaust gas is then introduced into the radioactivity attenuation removal device 110 and treated. Thereafter, the vacuum pump 11 guides the gas to the exhaust pipe 112 and discharges it into the atmosphere. At this time, the number of electric heaters 104 is controlled to increase or decrease through the controller 10B based on the detection signals from the exhaust gas inlet temperature detector 106 and the catalyst temperature detector 107, so that the gas temperature becomes suitable for the recombination reaction. It is controlled as follows. For example, a recombination reaction within the catalyst 103 of the container body 112 progresses and the catalyst 103
The temperature inside increases. This heat is transferred to the inside of the gas rift input pipe 114 through the pipe wall of the gas inflow pipe 114, and the inside of the gas inflow pipe 114 also becomes high temperature. At this time, the controller 10B de-energizes the electric heater 1θ4 in response to the detection signals from both temperature detectors 106 and 107, thereby stopping the heating by the electric heater 104. Further, even if the recombination reaction progresses, the temperature does not rise if the water purple concentration in the exhaust gas is low. Therefore, in this case, the electric heater 104
Electricity is applied to a portion of the heating element, and heating continues.

Next, the operation will be described when the plant is stopped or when a plurality of radioactive gas waste treatment apparatuses are installed in parallel, one of which is in operation and the other apparatus is on standby. That is, during standby, no flow of exhaust gas occurs within the container body 112 of the recombiner 102. At this time, K is used to prevent moisture from condensing, and to prevent the recombination reaction from being suppressed due to the temperature inside the container body 112 and the catalyst 103 dropping at the start of operation. Electricity is supplied and heating is performed by the multi-electric heater 104. Then, the gas staying in the gas inflow pipe 114 is heated and its temperature increases. The catalyst 103 is then heated through this gas. In this case, since the electric heater 104 has the main purpose of heating the catalyst 103, it is controlled via the controller 10B based on the detection signal of the catalyst temperature detector 107. Even when the device is on standby in this way, the inside of the container body 112 and the catalyst 103U
: Since the temperature is maintained at an appropriate temperature, the recombination reaction is not inhibited when the operation is started, and the I-turn can be carried out smoothly.

Next, maintenance work for the electric heater 104 during periodic inspections will be explained.

At this time, the heater mounting pipe 115 and the upper end 7 run section 112A of the container body 112 are tightened. The removal is done by removing the sushi from the container body 112. Furthermore, if only an electrical test is to be performed, the test can be carried out simply by removing the terminal cover 116 and exposing the terminal 117 of the electric heater 104.

That is, by providing the electric heater 104 in the recombiner 1θ2, the recombiner 102 has an exhaust gas heating function, which makes the conventional preheater unreliable. Therefore, is the preheater's internal number as a heat source? No need to drive irra,
Cost reduction can be achieved. In addition, since the exhaust gas is heated by the electric heater 104 inside the container body 112, it is efficient (compared to the conventional heating method using steam from an in-house boiler). It won't overheat. This is extremely effective in maintaining the exhaust gas temperature at an appropriate level and preventing excessive heating, thereby reducing costs. When the recombination reaction progresses and the temperature of the catalyst 103 becomes sufficiently high, a detection signal from the catalyst temperature detector causes the stain gas heater 10゛4 to
It is extremely economical because it allows operations such as stopping the heating of the fuel. Furthermore, even in the unlikely event that a part of the electric heater 104 is disconnected, uneven temperature distribution will not occur in the container body 112 and inside the container body 1.
The quality of the catalyst 12, the catalyst 103, etc. can be reliably maintained.

Next, a second embodiment will be described with reference to FIG. That is, the gas inlet pipe 113 passes through the lower end of the container body 112.
is installed. A gas inflow pipe 114 is disposed to communicate with this gas inlet pipe 113 and penetrate through the container body 112. At both ends of the gas inflow pipe 114, flanges 114 are formed with flanges 114B, and the heater attachment pipes 115 are fastened with delts, respectively.

Each of these heater attachment tubes 115 is provided with a terminal cover 116.

In the gas inlet 1 pipe 114, there is a gas inlet 4z pipe 1.
13 with a predetermined interval in the axial direction.
123B and 123c are provided. The partition plates 123A and 123C have an opening 124k between them and the 7 langes 115A of the heater attachment pipe 115 at both ends thereof.
.

124C, and the partition plate 123B has an opening 124B in its center. And these partition plates 12
3, a plurality of electric heaters 104 are provided between 123B and 123c, and are connected to each other via a cable 116) and a VC terminal 117 that passes through the heater attachment tube 115. And gas inflow pipe 1
A plurality of openings 126 are formed in the upper end side wall of 14.

In addition, the upper part of the gas inflow pipe 114 is connected via a screen stand 119.
Filled with 1M103. A gas outflow pipe 122 is provided at the upper part of the side wall of the container body 112.

That is, the gas inflow pipe 11 via the gas inlet pipe 113
The exhaust gas that has flowed into the interior of 4 is passed through the opening 124k.

The gas flows through the gas inflow pipe 114 from the bottom to the top via 124B and 124C. At that time, electric heater 1
The temperature is raised to an appropriate temperature by heating at θ4. The gas then flows out from the opening 126 of the gas inflow pipe 114 and flows into the catalyst 103 .

Oxygen and hydrogen in the exhaust gas undergo a recombination reaction within the catalyst 103, and the hydrogen in the exhaust gas is removed and flows out from the gas outflow pipe 122.

According to the above configuration, the electric heater 104 is connected to the container body 112.
Since it is installed at the lower part of the container body 112, the convection effect is good and the temperature distribution inside the container body 112 is uniform, especially during standby. In addition, when removing the electric heater 104, it is sufficient to remove the terminal cover 116 one by one or as a unit of several pieces, and the heater mounting pipe 115 can be removed.
There is no need to remove the flange II4 from the flange 114B, making maintenance work easier.

Next, a 30th embodiment will be described with reference to FIGS. 5 to 7. That is, a plurality of divided heaters 130 and 131 are provided on the outer surface of the recombiner 102.

The divided heaters 130 and 131 are connected to an upper thermometer 132 and a lower thermometer 133 inserted into the recombiner 102.
It is set up so that it envelops each. Further, the recombiner 102 is filled with a catalyst layer 134, and the divided heaters 130 and 131 are installed so as to protrude from the upper and lower ends of the catalyst layer 134. These divided heaters 13θ and 131 each have a terminal box 135 and are connected to a power supply system (not shown). Then, on the outer surface of the recombiner 102, the divided heater 1 is provided.
A heat insulating layer 136 is provided to cover 30 and 131. In addition, 136A in the figure is a divided heater 13θ and 1
31 is an intermediate heat insulating layer provided between the The divided configuration of the divided heaters 130 and 131 is determined depending on the size of the recombiner 102, the presence or absence of the projection 137 of the recombiner 102, etc., as shown in FIG. and protrusion 13
This is a configuration in which the heater capacity is the sum of the heat dissipation amount of 7.

Further, when the temperature difference between the upper thermometer 132 and the lower thermometer 133 exceeds a specified value, the voltage is changed to change the capacitance, thereby making the temperature of the catalyst layer 134 uniform. Further, by variously changing the connection of the divided heaters 130 and 131, a uniform temperature distribution can be easily obtained.

According to the above configuration, the divided heaters 130 and 13 are configured to protrude from the upper and lower ends of the catalyst layer 134, so that the divided heaters 130 and 131 create an air layer above and below the catalyst layer 134. is not heated, therefore there is little air convection, and the temperature difference in the catalyst layer can be kept small. This is the 8th
Illustrated with reference to the figure. In FIG. 8, the upper thermometer 132 is plotted on the horizontal axis.
The height L from to the top surface of the catalyst layer 134 is taken, and the temperature difference ΔT between the upper thermometer 132 and the lower thermometer 133 is plotted on the vertical axis.
FIG. 3 is a diagram comparing the conventional case and the case of this embodiment. As is clear from this, in the conventional case (shown by the solid line in the figure), the thick h
A difference in P degree has occurred. This is because the air layer is heated and an air convection phenomenon involving the upper thermometer 132 occurs. On the other hand, in the case of this embodiment (indicated by the solid line in the figure), most of the temperature difference is seen and is dangerous due to the above-mentioned reason. In addition, by dividing the heater, it is possible to freely attach heaters of different capacities, and even if the capacities are the same, by changing the wiring combination or voltage, it is possible to improve the temperature balance. temperature can be optimally controlled.

〔Effect of the invention〕

The radioactive gas waste treatment apparatus according to the present invention includes an air extractor for extracting lid gas, and a recombiner for recombining oxygen and hydrogen in the exhaust gas by accommodating a catalyst therein and introducing the exhaust gas from the air extractor. This configuration includes a recombiner, a heater provided in the recombiner, and a control mechanism for controlling the heater.

In other words, by providing a heater in the recombiner, the recombiner has an exhaust gas heating function, eliminating the need for a conventional preheater, and increasing efficiency and reducing costs by heating from inside the recombiner container. This is the configuration that aims to achieve this.

Therefore, the problems that occur when using a preheater can be solved, and costs can be reduced and workability during maintenance etc. can be improved. Since the exhaust gas is heated by a heater, the control side is good, and since heating is performed from inside the recombiner container, efficiency is high and the wall surface of the container is not heated more than necessary. Furthermore, even if a part of the heater is damaged, non-uniformity of temperature within the container and on the wall surface of the container will not occur, which is extremely effective in maintaining the quality of the catalyst and the container.

[Brief explanation of the drawing]

FIG. 1 is a schematic system diagram of a conventional radioactive gas waste treatment device, FIGS. 2 and 3 are diagrams showing a first embodiment of the present invention, and FIG. 2 is a schematic diagram of a radioactive gas waste treatment device. System diagram,
FIG. 3 is a longitudinal sectional view of the recombiner, FIG. 4 is the same view showing the second embodiment, FIGS. 5 to 7 are views showing the third embodiment, and FIG. 5 is a front view. FIG. 6 is a perspective view, FIG. 7 is a sectional view, and FIG. 8 is a diagram showing the effects of the third embodiment. 101... Exhaust gas extractor, 102... Recombiner, 1
03... Catalyst, 104... Electric heater, 105...
・Control] measures. Applicant's agent Patent attorney Takehiko Suzue Figure 1 11 Figure 3

Claims (2)

[Claims] (1) An exhaust gas extractor that extracts exhaust gas, a recombiner that houses a catalyst inside and introduces the color of the exhaust gas from the exhaust gas extractor to re-feed oxygen and hydrogen in the exhaust gas, and a recombiner that 1. A radioactive gas waste processing apparatus comprising: a heater provided in a coupler; and a control mechanism for controlling the heater. (2) The control mechanism includes a catalyst temperature detector that detects the temperature in the catalyst, an exhaust gas inlet temperature detector that detects the temperature of the exhaust gas inlet of the recombiner, and these catalyst temperature detectors and the exhaust gas inlet. 2. The radioactive gas waste treatment apparatus according to claim 1, further comprising a controller that controls the heater based on a signal from a temperature detector.