JPH0735896A - Radioactive gas waste treatment equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the equipment installation space and simplify piping. [Structure] A heat transfer tube 24 serving as a preheating section is arranged in the center of the outer case 11, and an inner case 16 is provided so as to surround the heat transfer tube 24.
A catalyst that becomes a recombination part in the annulus space 18 between the outer shell 16 and the outer shell 11.
A plurality of buckets 19 filled with 20 are arranged. Bucket 19
The inner case 16 is cantilevered by the partition plate 12. A condensing cylinder 29, which serves as a condensing part, is connected to the outside of the partition plate 12. A weir plate 33 and a heat transfer tube 34 are provided in the condensing cylinder 29. The exhaust gas flows between the annulus space 18 and the outside of the bucket 19, exchanges heat of catalytic reaction, enters the preheating section, and reacts (recombines hydrogen and oxygen) in the bucket 19. After that, the water in the exhaust gas is removed in the condensing unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recombiner for recombining hydrogen and oxygen generated by radiolysis of water by a catalytic reaction in a radioactive gas waste treatment system installed in a nuclear power plant or the like. Its peripherals, such as preheaters,
The present invention relates to a radioactive gas waste treatment device having an improved condenser.

[0002]

2. Description of the Related Art Exhaust gas produced in a nuclear power plant, etc. contains not only the air and hydrogen and oxygen produced by the radiolysis of water flowing into the main condenser, but also the gas and fission product gas that are activated in the reactor. , And these are treated by the radioactive gas waste treatment system shown in FIG. 4, for example.

That is, in FIG. 4, reference numeral 1 is an air extractor, which is connected to a turbine condenser (not shown). An exhaust gas preheater 2, an exhaust gas recombiner 3, and an exhaust gas condenser 4 are sequentially connected downstream from the steam type air extractor 1.

Although not shown, the downstream side of the exhaust gas condenser 4 is sequentially connected with an exhaust gas precooler, an exhaust gas dryer, a pre-filter, an activated carbon type rare gas holdup tower, an exhaust gas particle filter, and a vacuum pump facility. An exhaust stack 5 for discharging the treated exhaust gas to the atmosphere is connected.

The exhaust gas recombiner 3 has an electric heater 6
Are installed, and the devices are connected by pipes 7, 8, and 9. Also, these are installed in two systems, and one system is in standby for standby.

In the radioactive gas waste treatment system, after the exhaust gas from the turbine condenser is extracted by the air extractor 1, the hydrogen and oxygen are combined with the exhaust gas recombiner in order to keep the exhaust gas below the flammability limit. In 3, steam is recombined by catalytic reaction to form steam.

Further, in order to maintain the reactivity of the catalyst, the exhaust gas is heated by the exhaust gas preheater 2 to a superheated state. On the other hand, the steam used for extracting the exhaust gas and the steam generated by the recombination are returned to the main condenser as condensate in the exhaust gas condenser 4.

As described above, the exhaust gas preheater 2 preheats the exhaust gas with high temperature steam in order to maintain the catalytic performance of the exhaust gas recombiner 3. The exhaust gas recombiner 3 combines hydrogen in the exhaust gas with oxygen by the function of a catalyst to convert it into water vapor for the safety of the treatment.

The exhaust gas condenser 4 cools the exhaust gas and removes water vapor to reduce the amount of gas. The exhaust gas that has become a non-condensable gas has its radioactivity reduced to below the permissible limit by the above-mentioned devices, and is discharged into the atmosphere from the exhaust stack 5 by the vacuum pump facility.

[0010]

The exhaust gas preheater 2, the exhaust gas recombiner 3 and the exhaust gas condenser 4 of the radioactive gas waste treatment system are individually installed. Therefore, the pipes 7, 8 and 9 between these devices have a problem in that the installation space becomes redundant and the installation space is expanded due to the routing such as thermal stress relaxation.

Further, the exhaust gas recombiner 3 has a structure in which the catalyst is directly filled in the container, and in order to maintain the dryness of the catalyst,
Since it is necessary to install the electric heater 6 as an incidental facility, handling of the catalyst and maintenance are troublesome, and there is a problem that the heat of catalytic reaction is not effectively used.

The present invention has been made to solve the above-mentioned problems, and downsizing the equipment and the installation space accompanying it, improving the handleability and maintenance of the catalyst, and effectively utilizing the heat of reaction of the catalyst. In view of the above, an object of the present invention is to provide a radioactive gas waste treatment device in which the electric heater of the auxiliary equipment is removed.

[0013]

According to the present invention, an outer shell having an exhaust gas inlet nozzle, a condensing cylinder having an exhaust gas outlet nozzle connected to the outer shell, an exhaust gas preheating section provided in the outer shell, and It is characterized by comprising a recombining part and a condensing part provided in the condensing cylinder for condensing the exhaust gas flowing out from the recombining part.

[0014]

[Operation] Exhaust gas accompanied by water vapor extracted from the steam-type air extractor flows in through the exhaust gas inlet nozzle and is divided into a portion surrounded by the outer and inner shells and a concentrically arranged bucket filled with the catalyst. Baffles were used to convert the annulus space,
Passes while forming a uniform flow. At this time, the reaction heat generated by the recombination of hydrogen and oxygen in the bucket is transferred via the bucket, and the exhaust gas flows into the inner case from the inner case inlet nozzle.

Exhaust gas accompanied by water vapor flowing into the inner body passes while meandering by the baffle, and during this time, it is efficiently heated through the heat transfer tube by the heating steam supplied from the heating steam nozzle and flowing out from the heating steam outlet. While passing through the catalyst in the bucket via the recombiner inlet chamber, hydrogen and oxygen in the exhaust gas are recombined by the catalytic reaction to become steam, and reach the recombining unit outlet chamber.

Exhaust gas accompanied by water vapor flowing into the condensing cylinder is supplied from the cooling water inlet nozzle while meandering by the baffle, and is efficiently cooled by the cooling water flowing out from the cooling water outlet nozzle via the heat transfer tube.

As a result, the water vapor in the exhaust gas is condensed, and only the saturated non-condensable gas in the exhaust gas flows out from the exhaust gas outlet nozzle. On the other hand, the condensate generated in the condensate cylinder stays between the weir and the condensate cylinder and flows out from the condensate nozzle.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a radioactive gas waste treatment apparatus according to the present invention will be described with reference to FIGS.
Note that FIG. 2 is an enlarged cross-sectional view taken along the line AA ′ in FIG.

In FIG. 1, reference numeral 10 indicates the entire radioactive gas waste treatment apparatus of the first embodiment. Reference numeral 11 denotes an outer case, one end of which is closed by a partition plate 12 and the other end of which is closed by a heating steam lid 13. Heating steam lid 13
A heated steam inlet nozzle 14 and a heated steam outlet nozzle 15 are connected to the.

Inside the outer case 11, an inner case 16 having one end fixed by a partition plate 12 is provided. An inner barrel inlet nozzle 17 is provided in the inner barrel 16 near the partition plate 12. Inner body 16 is outer body
An annulus space 18 is formed between the inner body 16 and the outer body 11 and is arranged concentrically with respect to 11.

A plurality of buckets 19 are annularly arranged in the annulus space 18 as shown in FIG. 2, and one end of the bucket 19 is attached to the partition plate 12. The bucket 20 is filled with the catalyst 20.

An exhaust gas inlet nozzle 21 is connected to the lower surface of the outer case 11, and a baffle 22 is partially provided so as to surround the bucket 19 between the outer case 11 and the inner case 16. Inner body
The other end of 16 has a bent portion 23, and this bent portion 23 supports the other end of the bucket 19.

A heat transfer tube 24 for heating exhaust gas is inserted in the inner case 16, and the other end of the heat transfer tube 24 is fixed to a tube plate 25.
The tube sheet 25 is connected to the flange 26 of the heating steam lid 13.
The heat transfer tube 24 is provided with baffles 27 of large and small diameters. Support legs 28 are welded to the outer case 11.

On the other hand, a flange portion 30 of a condenser barrel 29 is connected to the other end surface side of the partition plate 12, and the condenser barrel 29 has a large diameter portion 31 and a small diameter portion.
It consists of 32 and. The large diameter portion 31 is provided with a weir plate 33, and the small diameter portion 32 is inserted with a heat transfer pipe 34 for cooling exhaust gas. An end of the heat transfer tube 34 is fixed to a tube plate 35, and a cooling water lid 36 is connected to the tube plate 35. A cooling water inlet nozzle 37 and a cooling water outlet nozzle 38 are connected to the cooling water lid 36.

An exhaust gas outlet nozzle 39 is connected to the small diameter portion 32. A condensate nozzle 40 is connected to the lower surface of the large diameter portion 31 located below the weir plate 33, and a support leg 41 is welded to the lower surface of the small diameter portion 32. In the figure, reference numeral 42 is a recombining portion inlet chamber, and 43 is a recombining portion outlet chamber.

Next, the operation of the radioactive gas waste treatment device according to the above configuration will be described. Exhaust gas accompanied by water vapor extracted from the steam-type air extractor flows in through the exhaust gas inlet nozzle 21, and as shown in FIG. 2, a plurality of exhaust gas are installed concentrically with the portion surrounded by the outer body 11 and the inner body 16. The baffle 22 passes through the annulus space 18 with the bucket 19 filled with the stored catalyst 20 while being turned by a baffle 22 while forming a uniform flow.

At this time, the bucket 19 filled with the catalyst 20
The reaction heat generated by the recombination of hydrogen and oxygen inside the bucket
It is sent and received via 19 and flows into the inner case 16 from a plurality of inner case inlet nozzles 17 which are concentrically installed.

Exhaust gas accompanied by steam flowing into the inner case 16 meanders through the baffle 27, and is supplied from the heating steam inlet nozzle 14 during this time, and is supplied from the heating steam outlet nozzle.
The heated steam flowing out from 15 efficiently heats the heat transfer tube 24 to pass through the recombination part inlet chamber 42 and the catalyst 20 in the bucket 19 while passing through the catalyst 20 so that hydrogen and oxygen in the exhaust gas are recombined. Then, it becomes steam and reaches the recombination section outlet chamber 43.

Exhaust gas accompanied by steam that has flowed into the condensing cylinder 29 is meandering by the baffle 49, and is cooled by a cooling water inlet nozzle.
Cooling water supplied from 37 and flowing out from the cooling water outlet nozzle 38 is efficiently cooled through the heat transfer tube 34, whereby water vapor in the exhaust gas is condensed and becomes a saturated wet state in the exhaust gas. Only the gas flows out from the exhaust gas outlet nozzle 39. On the other hand, the condensate 50 generated in the condensate cylinder 29 is
And the condensate barrel 29, and is discharged from the condensate nozzle 40.

According to the first embodiment described above, there are the following effects. (1) An exhaust gas recombiner for recombining hydrogen and oxygen generated by activation of water in a gas waste treatment system for treating radioactive gas waste (exhaust gas) generated in nuclear power plants, etc., and this exhaust gas By integrating an exhaust gas preheater for preheating exhaust gas before flowing into the recombiner and an exhaust gas condenser that condenses water vapor in exhaust gas flowing out of the exhaust gas recombiner into the same device, The installation space of the equipment can be reduced. In addition, since a piping system between each device is not required, installation space can be reduced and on-site construction can be omitted.

(2) By separately filling the catalyst into each bucket, handling and maintenance of the catalyst can be improved. (3) Generated by a catalyst by arranging them concentrically around the inner shell that surrounds the preheating section, and using the gap between the inner shell that surrounds the preheating section and the outer shell that surrounds the entire bucket as the exhaust gas flow path to the preheating section. The heat can be effectively used for preheating exhaust gas. As a result, the amount of heating steam used during the operation period is reduced, which has the effect of cost reduction.

(4) The bucket, the inner case, the outer case, and the bucket and the outer case are supported in a cantilever manner so as to absorb the difference in thermal expansion between them, so that an integrated structure can be achieved. (5) As a function of maintaining the temperature of the exhaust gas recombiner during standby, the preheating part and the recombining part can be integrated so that an operation that doubles as the preheating part can be used instead of a method using an electric heater or the like.

Next, a second embodiment of the present invention will be described with reference to FIG. The gaseous waste treatment device 44 in the second embodiment is the one in which the condensate part connected to the preheating part and the recombining part is deleted in FIG. 1 and only the preheating part and the recombining part are provided. That is, the second embodiment is different from the first embodiment in that the outlet lid 45 is connected to the other end surface side of the partition plate 12 via the lid side flange 46, and the exhaust lid 45 has an exhaust gas outlet nozzle 47 and a drain nozzle. 48 is connected.

In the second embodiment, the exhaust gas preheating section and the recombining section are integrated with each other, and the construction is the same as in the first embodiment. Therefore, the description of the overlapping portions will be omitted. The operation is almost the same as that of the first embodiment except the condensing section.

According to the second embodiment, the preheating section and the recombining section are not concentrically arranged in series, but are concentrically arranged. A structure effective also in terms of thermal characteristics is realized.

Further, at the time of handling and maintenance of the catalyst, the flange joints of the preheating portion and the re-joining portion can be disassembled, and the buckets filled with the catalyst can be disassembled and removed. The maintainability can be improved. Furthermore, the exhaust gas can effectively utilize the reaction heat generated in the recombination part when passing through the annulus space.

In addition, by operating the preheating section during standby, the temperature of the recombining section can be increased, and the electric heater which was conventionally required as auxiliary equipment for the recombiner can be eliminated. In each of the above embodiments, the horizontal type processing device is described, but a vertical type processing device may be used.

[0038]

According to the present invention, the catalytic reaction of the recombining portion is achieved by integrating the preheating portion and the recombining portion, the preheating portion, the recombining portion and the condensing portion, and disposing the bucket around the preheating portion. It is possible to effectively use heat and improve maintenance of the recombination part, reduce the equipment installation space and simplify the piping arrangement, and reduce the number.

[Brief description of drawings]

FIG. 1 is a first radioactive-gas waste treatment device according to the present invention.
FIG. 6 is a vertical cross-sectional view showing the embodiment of FIG.

FIG. 2 is a view on arrow AA ′ in FIG.

FIG. 3 is a second view of the radioactive gas waste treatment device according to the present invention.
FIG. 6 is a vertical cross-sectional view showing the embodiment of FIG.

FIG. 4 is a system diagram showing a conventional radioactive gas waste treatment system.

[Explanation of symbols]

1 ... Air extractor, 2 ... Exhaust gas preheater, 3 ... Exhaust gas recombiner, 4 ... Exhaust gas condenser, 5 ... Exhaust pipe, 6 ... Electric heater,
7, 8, 9 ... Piping, 10 ... Gas waste treatment device (first embodiment), 11 ... Outer shell, 12 ... Partition plate, 13 ... Heating steam lid, 14
… Heating steam inlet nozzle, 15… Heating steam outlet nozzle, 16…
Inner barrel, 17 ... Inner barrel inlet nozzle, 18 ... Annulus space, 19 ...
Bucket, 20 ... Catalyst, 21 ... Exhaust gas inlet nozzle, 22 ... Baffle, 23 ... Bent section, 24 ... Heat transfer tube, 25 ... Tube plate, 26 ... Flange, 27 ... Baffle, 28 ... Support leg, 29 ... Condenser cylinder , 30 ... Flange part, 31 ... Large diameter part, 32 ... Small diameter part, 33 ... Weir plate, 34 ... Heat transfer tube, 35 ... Tube plate, 36 ... Cooling water lid, 37 ... Cooling water inlet nozzle, 38 ... Cooling water Outlet nozzle, 39 ... Exhaust gas outlet nozzle, 40
… Condensation nozzle, 41… Support leg, 42… Recombining part inlet chamber, 43…
Recombining section outlet chamber, 44 ... Gas waste treatment device (second embodiment), 45 ... Outlet lid, 46 ... Lid side flange, 47 ... Exhaust gas outlet nozzle, 48 ... Drain nozzle, 49 ... Baffle, 50 ... Condensate .

Claims (4)

[Claims] 1. An outer shell having an exhaust gas inlet nozzle, and a condenser shell having an exhaust gas outlet nozzle connected to the outer shell,
A preheating part and a recombining part of exhaust gas provided in the outer case,
A condensate unit provided in the condensing cylinder for condensing the exhaust gas flowing out from the recombining unit, the radioactive gas waste treatment device. 2. The preheating section preheats exhaust gas,
The inner shell is concentrically arranged with an annulus space in the outer shell, and an exhaust gas heating heat transfer tube inserted in the inner shell, and the recombining portion is arranged in the annulus space. The bucket is composed of a plurality of buckets and a catalyst filled in the bucket, and the condensate part is composed of an exhaust gas cooling heat transfer tube inserted in the condensing cylinder and a weir plate. A recombining portion inlet chamber is formed on the inflow side, a recombining portion outlet chamber is formed between the dam and the partition plate, and a condensate nozzle is provided on the downstream side of the dam. The radioactive gas waste treatment device according to claim 1. 3. An outer shell having one end closed by a partition plate and the other end closed by a heating steam lid, and a concentric circle having an annulus space inside the outer shell, and one end of which is the partition plate. A fixed inner cylinder, a plurality of buckets arranged in the annulus space and having one end fixed to the partition plate, a catalyst filled in the bucket, and an exhaust gas heating transfer member arranged in the inner cylinder. Radioactive gas waste characterized by comprising a heat pipe, an exhaust gas inlet nozzle provided in the outer shell, an outlet cover connected to the partition plate, an exhaust gas outlet nozzle and a drain nozzle provided in the outlet cover. Material processing equipment. 4. The outer shell, the inner shell, and the bucket are supported by the partition plate in a cantilevered manner.
The described radioactive gas waste treatment device.