JPH10197191A - High-temperature side tube plate for multi-tube type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a temperature gradient in a tube plate gentle, and reduce thermal stress generated in the tube plate by a method wherein a heat insulating material is applied on the surface of the high-temperature side of a high- temperature side tube plate while a sleeve, for preventing the contact between the tube plate and high-temperature fluid, is inserted into the tube hole of the tube plate. SOLUTION: A sleeve 12 is inserted to the part of a heat transfer tube 11 so that high-temperature helium gas does not come into contact with the tube hole 10 of a tube plate 7 directly. The high-temperature side tube plate 7 is shielded from the high-temperature fluid by a heat insulating layer with a heat insulating cover 15 and the sleeve 12 whereby the temperature of the tube plate 7 is approached to that of low-temperature fluid or the temperature of water vapor, for example, thereby making the temperature gradient of the tube plate 7 more gentle. Accordingly, the temperature of the tube plate 7 is reduced and thermal stress, generated in the tube plate, can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helium gas heating type steam generator used in a system for performing steam steam reforming of hydrocarbons using the heat of helium gas in a high temperature gas furnace. The present invention relates to a structure of a high-temperature side tube sheet of a multi-tube heat exchanger in which a high-temperature fluid and a low-temperature fluid flow outside a tube.

[0002]

2. Description of the Related Art FIG. 4 shows a tube sheet structure of a conventional multi-tube heat exchanger.
Shown in In FIG. 4, reference numeral 1 denotes a tube sheet, and a plurality of tube holes 4 are provided in a perforated portion (ligament portion) 3, and a number of heat transfer tubes 5 are connected so as to communicate with the respective tube holes 4. I have. Reference numeral 2 denotes a high-temperature-side plenum on the inflow side of the high-temperature fluid to the tube sheet 1. A low-temperature-side plenum portion 6 through which a low-temperature fluid flows is formed outside the heat transfer tube 5.

In the multi-tubular heat exchanger having the tube-sheet structure shown in FIG. 4, a high-temperature fluid flows from the high-temperature-side plenum portion 2 through the tube hole 4 of the perforated portion 3 of the tube sheet 1 to form a heat-transfer tube 5. It flows inside. On the other hand, a low-temperature fluid flowing from an inlet (not shown) flows through the low-temperature side plenum 6 outside the heat transfer tube 5. Thus, the low-temperature fluid in the low-temperature side plenum 6 exchanges heat with the high-temperature fluid in the heat transfer tube 5 via the heat transfer tube 5.

[0004]

The tube sheet structure of the conventional multi-tube heat exchanger shown in FIG. 4 has the following problems.

(1) When a high temperature fluid flows through the inside of the tube hole 4 of the tube sheet 1, the temperature of the porous portion 3 of the tube sheet becomes close to the high temperature fluid temperature. For example, when helium gas of a high temperature gas furnace is used as the high temperature fluid, In order for the temperature of the high-temperature fluid to reach an extremely high temperature of 1000 ° C. and to give the tube sheet 1 strength against the internal and external pressures, it is necessary to make the tube sheet thickness very large.

(2) When a high temperature fluid flows through the inside of the tube hole 4 of the tube sheet 1 and there is a large temperature difference between the high temperature fluid and the low temperature fluid which exchanges heat (for example, a temperature difference of about 600 ° C.), the porous portion of the tube sheet 3
And a very large thermal stress is generated at the boundary of the rim and the thickness direction.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and in a multi-tube heat exchanger in which a high-temperature fluid flows inside a tube and a low-temperature fluid flows outside the tube, a temperature gradient inside a tube sheet is moderated. It is an object of the present invention to provide a high-temperature-side tube sheet capable of reducing thermal stress generated in a tube sheet portion.

[0008]

According to the present invention, in order to solve the above-mentioned problems, a heat insulating material is applied to a high-temperature side surface of a high-temperature side tube sheet, and the high-temperature fluid is brought into contact with the high-temperature side tube sheet. Provided is a high-temperature side tube sheet of a multi-tube heat exchanger having a structure in which a sleeve tube to be prevented is inserted into a tube sheet tube hole.

In the thus constructed high temperature side tube sheet of the present invention, the heat insulating material attached to the high temperature side surface and the sleeve sheet inserted into the tube hole of the tube sheet allow the tube sheet to come into contact with the high temperature fluid. Since there is no heat, the temperature of the tube sheet is reduced to near the low temperature fluid temperature, the temperature gradient in the tube sheet is moderated, and the thermal stress generated in the tube sheet portion is reduced.

According to another aspect of the present invention, in order to solve the above-mentioned problems, an insert tube is inserted into a tube plate tube hole in place of the above-mentioned sleeve tube, and heat insulation is provided between the insert tube and the tube plate tube hole. A hot side tube sheet provided with a material is provided.

In the thus constructed tube sheet, the tube plate tube hole is shielded from the high-temperature fluid by the heat insulating material and the insert tube. The effect of bringing the temperature of the plate closer to the low-temperature fluid temperature and further reducing the temperature gradient in the tube plate can be exhibited.

Still another object of the present invention is to provide a heat-insulating material on a high-temperature side surface of a high-temperature side tube sheet, and to provide a high-temperature fluid inlet side in the tube hole of the tube sheet. Provided is a high-temperature side tube sheet of a multi-tube heat exchanger having a configuration in which an end portion is expanded, and a heat insulating material for insulating the high-temperature side tube sheet from a high-temperature fluid is attached to the expanded portion.

[0013] In the high temperature side tube sheet thus configured, heat transfer from the high temperature fluid is hindered by the heat insulating material including the pipe hole portion, and the temperature of the tube sheet approaches the low temperature fluid temperature. Slow the temperature gradient. Further, in the high temperature side tube sheet having this configuration, it is not necessary to mount the sleeve tube or the insert tube in the tube sheet tube hole, so that the processing is easy. Thus, in the high temperature side tube sheet, the thermal stress generated in the tube sheet portion can be effectively reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-temperature side tube sheet of a multi-tube heat exchanger according to an embodiment of the present invention will be specifically described below.

(First Embodiment) First, a description will be given of a high temperature side tube sheet according to a first embodiment shown in FIG. In FIG. 1, reference numeral 7 denotes a high temperature side tube sheet, and the high temperature side tube sheet 7 is provided with a tube sheet tube hole 10. Reference numeral 11 denotes a heat transfer tube. A heat insulating layer 9 is provided on the surface of the tube sheet 7 facing the high temperature side plenum portion 8, and the surface of the heat insulating layer 9 is provided with a heat insulating cover 15.
Covered with.

The sleeve tube 12 is inserted into the tube hole 10 so that the high temperature helium gas at about 900 ° C. does not come into direct contact with the tube plate 7.
Is inserted up to the heat transfer tube 11. The end of the sleeve tube 12 is formed larger than the tube sheet tube hole 10 in a state of being inserted into the tube sheet tube hole 10 and bent into an L-shape so as to abut the heat insulating cover 15. The end of the sleeve tube 12 in contact with the heat insulating cover 15 is the heat insulating cover 1
5 is welded to prevent slipping.

Since the high temperature side tube sheet shown in FIG. 1 is configured as described above, the high temperature side tube sheet 7 is shielded from the high temperature fluid by the heat insulating layer 9 with the heat insulating cover 15 and the sleeve tube 12. The temperature of the plate 7 is brought close to the temperature of a low-temperature fluid, such as steam (about 250 ° C.), which is a low-temperature fluid, and the temperature gradient in the tube plate 7 can be further reduced. And the thermal stress generated in the tube sheet portion can be reduced.

Second Embodiment Next, a description will be given of a high temperature side tube sheet according to a second embodiment shown in FIG. In FIG. 2, the high temperature side plenum portion 8 side of the high temperature side tube sheet 7 is covered with a heat insulating layer 9 with a heat insulating cover 15 as in the case of the first embodiment.

On the other hand, in order to insulate the high-temperature side tube sheet 7 from the high-temperature helium of about 900 ° C. flowing through the tube sheet tube hole 10, an insert tube 14 provided with a heat insulating material 13 on the outer surface is partially connected to the heat transfer tube 11. It has been inserted until. This insert tube 1
4 are bent outward so that the end inserted into the tubesheet tube hole 10 has a slightly smaller diameter than the tubesheet tube hole 10 and the other end is larger than the tubesheet tube hole 10. It is molded to.

When the insert tube 14 thus formed is inserted into the tube sheet tube hole 10, the state shown in FIG. 2 is obtained, and the end of the insert tube 14 of the high-temperature side plenum portion 8 abuts on the heat insulating cover 15. The portion is welded to prevent slippage 11 as shown.

In the high temperature side tube sheet 7 of FIG. 2 configured as described above, the temperature approaches the temperature of a low temperature fluid, for example, steam (about 250 ° C.), and further, the temperature gradient in the tube sheet 7 is moderated. The effect can be exhibited, the temperature of the tube sheet 7 can be lowered, and the thermal stress generated in the tube sheet portion can be reduced.

(Third Embodiment) Next, a description will be given of a high-temperature side tube sheet according to a third embodiment shown in FIG. FIG.
As shown in the figure, the tube sheet 7 has a slope 16 from the end facing the high-temperature side plenum 8 to the connection with the heat transfer tube 11.
Are formed. Then, the heat insulating cover 15 is formed so as to cover the tube sheet tube hole in which the inclined portion 16 is formed.
The heat insulating cover 15 and the inclined portion 16 of the tube plate tube hole are extended.
The heat insulating material 9 is also provided in the heat insulating part 17 of the.

Thus, the hot side tubesheet of FIG.
It is insulated from the high temperature helium of 0 ° C., thereby bringing the temperature of the tube sheet 7 close to the temperature of steam (about 250 ° C.) which is a low temperature fluid, and can further exert the effect of reducing the temperature gradient in the tube sheet 7. 7 can be lowered to reduce the thermal stress generated in the tube sheet portion. Further, in the tube sheet of the present embodiment, the inner diameter of the tube sheet tube hole does not change, so that the flow of the high-temperature fluid inside can be smoothly performed.

[0024]

As described above, the high-temperature side tube sheet of the multi-tube heat exchanger according to the present invention is composed of a heat insulating material installed on the high-temperature side surface, a sleeve tube or an insert tube inserted into the tube plate tube hole. The heat insulating material shields the high-temperature fluid from the high-temperature fluid, lowers the temperature to the low-temperature fluid temperature, reduces the thermal stress generated in the tube sheet portion, and further has the effect of reducing the temperature gradient in the tube sheet.

Further, according to the present invention, a heat insulating material is applied to the high-temperature side surface, and the high-temperature fluid inlet side end of the tube plate tube hole is enlarged. In this configuration, a heat insulating material is installed to insulate the tube sheet from the high temperature fluid, and the heat insulating material and the heat insulating cover shield the tube sheet from the high temperature fluid to bring the temperature of the tube sheet close to the low temperature fluid temperature, and furthermore, the temperature gradient in the tube sheet The effect of relaxing the time can be exhibited. Also,
There is no change in the inner diameter at the tube plate tube hole, and the flow of the internal fluid can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a high-temperature side tube sheet according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a high-temperature side tube sheet according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a configuration of a high-temperature side tube sheet according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a conventional high temperature side tube sheet.

[Explanation of symbols]

 REFERENCE SIGNS LIST 7 high-temperature side tube sheet 8 high-temperature side plenum part 9 heat insulating layer 10 tube sheet tube hole 11 heat transfer tube 12 sleeve tube 13 heat insulating material 14 insert tube 15 heat insulating cover 16 inclined portion 17 heat insulating portion

Claims (3)

[Claims] 1. A high-temperature side tube sheet of a multi-tube heat exchanger in which a high-temperature fluid flows inside a pipe and a low-temperature fluid flows outside the pipe. A high-temperature side tube sheet of a multi-tube heat exchanger, wherein a sleeve tube for preventing the high-temperature fluid from coming into contact with the tube sheet is inserted into a tube sheet tube hole. 2. The high-temperature side tube sheet of the multi-tube heat exchanger according to claim 1, wherein an insert tube is inserted into a tube plate tube hole instead of the sleeve tube, and the sleeve tube and the tube plate tube hole are connected to each other. High-temperature side tube sheet of multi-tube heat exchanger with insulation material provided between. 3. A high-temperature side tube sheet of a multi-tube heat exchanger configured so that a high-temperature fluid flows inside a pipe and a low-temperature fluid flows outside the pipe. And a configuration in which the inlet end of the high-temperature fluid in the tube hole of the tube sheet is enlarged, and a heat insulating material for insulating the high-temperature side tube sheet from the high-temperature fluid is attached to the enlarged portion. High-temperature side tube sheet of the multi-tube heat exchanger.