JPH0454916B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] This invention relates to a partition structure of an exhaust gas preheater installed in a gaseous waste treatment system of a nuclear power plant, and in particular, the invention relates to a partition structure of an exhaust gas preheater provided in a gaseous waste treatment system of a nuclear power plant. This invention relates to a partition structure of an exhaust gas preheater, in which the exhaust gas preheater is connected to the tube plate of the heat exchange fuselage body plate by welding and sealing, and a lid is provided at the other end via a sealing means to facilitate maintenance.

[Prior art]

At nuclear power plants, the treatment of radioactive materials is strictly controlled. For example, in the radioactive gas waste treatment system, an exhaust gas preheater is installed to prevent entrainment of water droplets that can adversely affect the catalyst in the exhaust gas recombiner of the same system equipment. It is designed to prevent

Therefore, the conventional structure of the exhaust gas preheater will be explained based on FIGS. 1 and 2.
The exhaust gas to be treated is passed through the tube side and the steam for heating is passed through the shell side. The heated steam flows inside the tube and exits from the exhaust gas outlet nozzle 6, while the heated steam enters from the heated steam inlet nozzle 7 and heats the exhaust gas flowing in the heat transfer tube 5 above the saturation temperature of the steam to entrain water droplets in the exhaust gas. The condensate is prevented from being formed, becomes condensate, and exits from the condensate outlet nozzle 8.

The partition chamber body plate 2 and the fuselage body plate 4 are connected via the tube plate 9, and the inside of the partition plate chamber, the exhaust gas side of the tube plate 9, and the heat exchanger tubes 5 can be inspected and repaired. Therefore, the fuselage flange 10 is integrally welded to the fuselage body plate 4, the partition flange 11 is integrally welded to the partition chamber body plate 2, and the three plates are tightened simultaneously with bolts with the tube plate 9 in between. It has been done.

By the way, exhaust gas is a fluid with radioactivity of 1 μμci/cc or more, and it is essential to prevent its leakage. Therefore, the shape of the joint between the exhaust gas inlet nozzle 3, exhaust gas outlet nozzle 6, and the connecting pipe is butt welded. This prevents sealing, and lip seal welding 12 is applied to the attachment portions of the tube plate 9 and the partition flange 11 to ensure airtightness.

Note that a partition plate 14 is welded and fixed between the hemispherical end plate 13 of the partition chamber body plate 2 and the tube plate 9 by appropriate means.

Although the above structural designs are designed to improve maintainability and prevent leakage, both have problems that are related to each other.

That is, as shown in the first section, since the tube plate 9 has a structure in which three sheets are fastened together, there is a drawback that the sealing performance is insufficient, and especially on the shell side where lip seal welding is not performed, heated steam leakage occurs. There are problems in which the risk of leakage cannot be completely avoided, such as the possibility that there is a large risk of leakage.

Second, when inspecting or repairing the partition chamber, the exhaust gas side of the tube plate 9, and the heat transfer tubes 5, remove the lip seal weld 12 with a grinder while keeping the bolts 15 attached, and then remove the lip seal weld 12 with a grinder. Maintenance is only possible after cutting the butt welds between the inlet nozzle 3 and the exhaust gas outlet nozzle 6 and the connecting pipe and removing the entire partition.

As a result, maintenance requires a large number of man-hours, is extremely cumbersome, and is difficult to perform.

Therefore, it has been desired to develop and improve drastic structural measures that can improve maintainability and prevent leakage without compromising each other, and can sufficiently achieve both functions.

[Purpose of the invention]

The purpose of this invention is to solve the problems of the exhaust gas preheater based on the above-mentioned prior art as a technical problem to be solved,
The present invention provides an excellent exhaust gas preheater partition structure that can achieve both improved maintainability and reliability of leakage prevention without contradicting each other, and is beneficial to the field of nuclear reactor application in the energy industry. .

[Summary of the invention]

In order to achieve the above object, the present invention provides a partition body plate, which is provided with an exhaust gas inlet nozzle and an exhaust gas outlet nozzle, and whose interior is partitioned into an exhaust gas inlet nozzle side and an exhaust gas outlet nozzle side by a partition plate; A tube sheet, one surface of which is joined to one end side of the partition body plate, and a heat transfer tube for transferring exhaust gas from the exhaust gas inlet nozzle side to the exhaust gas outlet nozzle side of the partition chamber body plate is attached, and the other side of the tube sheet. a heating steam inlet nozzle and a condensate outlet nozzle;
In an exhaust gas preheater having a body shell plate that accommodates heat transfer tubes inside, the joint between the partition chamber body plate and the tube plate and the joint between the tube plate and the body shell plate are welded, and the other end side of the partition chamber body plate is welded. A flange is formed, a flat cover is removably attached to the flange, a sealing means is provided between the flat cover and the flange, and a partition cover removably attached to the partition chamber body plate is removed from the partition plate. It is characterized by being able to be installed to partition the interior.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described based on the drawings from FIG. 3 onwards. Note that the same parts as in FIGS. 1 and 2 will be described using the same reference numerals.

In the embodiment shown in FIGS. 3 and 4, the base end of the fuselage shell plate 4 and the tube plate 9, and the tube plate 9 and one end of the partition body plate 2 are joined by direct welding, with the tube plate 9 Have been in contact with the junction.

Therefore, exhaust gas,
And there is no risk of leakage of heating steam.

Further, a flange 16 is previously formed on the other end of the partition body plate 2, and a flat cover 17 is attached via bolts 15 to facilitate maintenance.

In order to prevent exhaust gas from leaking from this portion, the diaphragm 18 is directly attached to the flange 16 by welding.

Therefore, as with the tube plate portion 9, there is no risk of exhaust gas leaking.

Since the partition plate 14' cannot be directly attached to the diaphragm 18 due to mechanical reasons, the partition cover 19 is attached to the bracket 20 provided inside the partition body plate 2, and the partition cover 1
9 with bolts 21, and the other end is welded to the tube plate 9 to partition the inlet side and the outlet side.

In the above configuration, the exhaust gas entering from the exhaust gas inlet nozzle 3 flows through the heat exchanger tube 5, undergoes heat exchange with steam, is heated to a temperature higher than the saturated vapor pressure, is prevented from entraining water droplets, and is discharged from the exhaust gas outlet nozzle 4. Therefore, when inspecting or repairing the partition chamber, the exhaust gas side tube plate 9 surface, and the heat transfer tube 5, first remove the bolts 15, remove the flat cover 17, and then weld the partition chamber flange 16. As shown in FIG. 4, the installed diaphragm 18 is fixed to the flange 16 of the partition body plate 2 by bolts 25 using a well-known appropriate diaphragm cutter 22 with its arm 23 via a spacer bushing 24, and then the motor 26 is connected. Then, the cutter 28 is rotated by the arm 27 to mechanically cut the welded portion and remove it.

Next, remove the bolts 15 and remove the partition cover 19.

Maintenance can be performed only by the above-mentioned operations, and therefore, there is no need to cut the butt welds between the exhaust gas inlet nozzle 3 and the exhaust gas outlet nozzle 6 and the connecting pipe, or to remove the entire partition chamber.

According to the above-described embodiment, it is possible to obtain high reliability in preventing leakage of exhaust gas, and also to obtain an effect of excellent maintainability.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to fundamentally prevent the leakage of exhaust gas and heated steam in the exhaust gas preheater with high reliability, and the excellent effect of further improving maintainability is achieved.

Furthermore, by directly welding one end of the partition chamber body plate and the body body plate to the tube plate, the sealing performance is extremely excellent, which greatly contributes to safety.

Since the other end of the partition body plate is also joined to the flat lid via the welded diaphragm, the welded joint is separated into left and right parts, which has the effect of improving sealing performance accordingly.

Since the flat cover can be removed and the welded portion removed using a grinder or the like, there is no need to remove the exhaust gas inlet/outlet nozzle, resulting in an excellent effect of easy maintenance.

In addition, since the welded portions are separated, the structure is simple, manufacturing is easy, and handling and management is easy, making it an excellent radioactive gas processing device.

[Brief explanation of the drawing]

FIG. 1 is a structural cross-sectional view showing the entire exhaust gas preheater according to the prior art, FIG. 2 is an enlarged cross-sectional view of the partition shown in FIG. 1, and FIG. 3 is a structure of a partition according to an embodiment of the present invention. FIG. 4 is an explanatory cross-sectional view of the diaphragm cutter in an inserted state. 14'...Partition plate, 3...Exhaust gas inlet nozzle, 6...
Exhaust gas outlet nozzle, 2... Partition chamber body plate, 5... Heat transfer tube, 7... Heating steam inlet nozzle, 8... Condensate outlet nozzle, 4... Body shell plate, 9... Tube plate, 1... Exhaust gas preheater, 17... Flat Lid, 18...Sealing means.

Claims (1)

[Scope of Claims] 1. A partition body plate provided with an exhaust gas inlet nozzle and an exhaust gas outlet nozzle, the interior of which is partitioned into an exhaust gas inlet nozzle side and an exhaust gas outlet nozzle side by a partition plate; and the partition chamber body plate. One side is joined to one end side of
and a tube plate to which a heat transfer tube is attached that transfers exhaust gas from the exhaust gas inlet nozzle side to the exhaust gas outlet nozzle side of the partition chamber body plate, and the tube plate is joined to the other surface of the tube plate and is connected to the heating steam inlet nozzle and condensate. In an exhaust gas preheater having an outlet nozzle and a body shell plate that accommodates the heat exchanger tube therein, the connection between the partition chamber body plate and the tube plate and the connection between the tube plate and the body body plate are made by welding. , a flange is formed on the other end side of the partition chamber body plate, a flat cover is removably attached to the flange, a sealing means is provided between the flat cover and the flange, and the flat cover is removably attached to the partition chamber body plate. An exhaust gas preheater characterized in that a partition cover attached to the partition plate is removably attached to the partition plate to partition the inside. 2. The exhaust gas preheater according to claim 1, wherein the sealing means is a diaphragm attached to the flange by welding. 3. The exhaust gas preheater according to claim 1, wherein the sealing means is a seal lip welded between the flange and the flat lid.