JPS6241593A - Multitubular type heat exchanger - Google Patents

Abstract

PURPOSE:To reduce the damage of a tube plate due to various corrosion cracks and the like and improve the operation reliability of the heat exchanger as well as normalcy of the tube plate by forming the tube plate by joining a surface plate to the main body surface of the tube plate through a group of projection and forming cooling water passages by the projection group between the tube plate main body and the surface plate. CONSTITUTION:A tube plate is constituted in such a manner that reticulate grooves are formed by machining to provide a group of projections 12a on the upper surface side of a tube plate main body 10, a surface plate 11 is integrally dispersed and joined by the interposition of the group of projections 12a, and cooling water passages 13a communicated vertically and horizontally by the group of projections 12a, are formed between the tube plate main body 10 and the surface plate 11. Tube holes 14 are formed at parts of desired projections 12a, and the ends of a tube 2 are loaded in the tube holes 14 by suitable means. Although respective cooling water passages 13a are formed up to the ends of the tube plate, it is possible to join the frame simultaneously by the dispersion joining to the outer periphery of the tube plate. Respective cooling water passages form vertical and horizontal channels between the tube plate main body 10 and the surface plate 11 and cooling water is circulated vertically and horizontally.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shell-and-tube heat exchanger used at high temperatures in ammonia plants and the like.

(Prior art) Equipment that handles fluids containing ammonia gas, such as in ammonia plants, decarburizes the fluid under high temperature and pressure.
There is a risk of various damages occurring such as hydrogen attack, nitriding and stress corrosion cracking, and the tube sheets of waste heat boilers, which are shell-and-tube heat exchangers, are particularly susceptible to all of these damages. At present, it is difficult to select the structure and material for the structure, and carbon steel cannot be used due to its high temperature strength, decarburization, oxidation, hydrogen attack, etc., and low alloy steel (mainly Or-Mo steel)
Since nitrided and austenitic stainless steels have the risk of corrosion cracking from the water side, currently tube sheets made of expensive high N1 solid materials such as Incoloy and Inconel or clad materials with low alloy steel are used. Usually, as shown in Figure 2, a tube (2) is attached to a tube plate (1) made of the above-mentioned material.
The end of the tube is inserted and welded (3), or the insulation material (5) is inserted on the tube plate (1) and the west side of the tube (2) as shown in Figure 3.
In some cases, a structure is adopted in which a ferrule (7) t'' is provided in addition to a ferrule (7) to lower the temperature of the tube sheet (1).

(Problems with the Prior Art) In the conventional tube sheet, a high Ni alloy such as Incoloy or Inconel is used, resulting in a significant increase in cost. 1
) and the tube plate (1) starting from the welding root (4) of the tube (2).
We have empirically confirmed that corrosion cracks that have propagated to the surface have occurred. It is very difficult to maintain the integrity of tubes over a long period of time due to deterioration and cracking of the tubes, deformation of ferrules, etc., and as soon as the above problems occur or the water level on the water side drops due to changes in operating conditions, the tube sheets will rise. There is a risk of heating the tube sheet and damaging it in a very short period of time. Furthermore, the installation of the ferrule reduces the area of the pipe inlet, resulting in problems such as increased flow resistance and clogging of the pipe hole.

(Object of the Invention, Means for Solving Problems) The present invention was developed in order to solve the above-mentioned problems, and includes a method in which a surface plate is joined to the main surface of the tube sheet through the interposition of a group of protrusions. , characterized in that the tube sheet is configured such that a cooling channel is formed between the tube sheet main body and the surface plate by the protrusion group, and the tube sheet is cooled by the interposition of the protrusion group between the tube sheet main body and the surface plate. By forming the water channels, the accuracy of the arrangement of the cooling channels as well as the tube sheet cooling performance and reliability are significantly improved, and damage to the tube sheet due to various types of corrosion cracking is extremely effectively and significantly reduced. It is an object of the present invention to provide a shell-and-tube heat exchanger that significantly improves the operational reliability of the exchanger and eliminates the above-mentioned problems.

(Example) Each embodiment of the present invention is shown in FIG. 1(A) or DJ. The first embodiment of the present invention shown in FIG. (On the upper surface side of the IQ, a mesh-like groove is formed by machining to provide a group of protrusions (12z), and on the a1 surface of the tube plate main body, the surface plate (upper tube plate) (11) t - the protrusion (
Cooling water channels (13a) (the mesh-like grooves) are integrally diffusion-bonded through the group of projections (12a) and communicated vertically and horizontally between the main body α1 of the tube plate and the surface plate α0 through the group of projections (12α). part) f, formed in a tube sheet which is formed and cut;
A pipe hole I is bored into the pipe hole I, and the end of the pipe (2) is attached to the pipe hole I by an appropriate means. In other words.

The portion where the tube hole α is formed is provided with the protrusion (12).

FIG. 1(B) shows a second embodiment of the present invention, in which, compared to the first embodiment, each protrusion (12A) has a cylindrical shape with a t-1 curved taper surface, and a group of protrusions (12b). Cooling channels (13A) are connected vertically and horizontally by
), and the other configurations are the same as those of the first embodiment.

Furthermore, a third embodiment of the present invention is shown in FIG. Subject 00
It fits into the hole (10α) on the upper surface of the first embodiment, and is connected vertically and horizontally by a group of protrusions (12C) to form a cooling water channel (13C). It has become.

Furthermore, FIG. 1(D) shows a fourth embodiment of the present invention, in which, compared to the first embodiment, parallel grooves are provided on the upper surface of the tube plate main body αQ, and a group of protrusions (12d) are provided. , Parallel grooves are provided on the upper surface to form a group of protrusions (22L:L).
1) e Interposed between the tube sheet main body (1) and the surface plate (11), the tube sheet main body (it), the intermediate plate (21) and the surface plate (1)
1) ft integrally diffusion bonded, and vertical and horizontal cooling channels (13d, 23
d), and while the first to third embodiments have a two-layer clad tube sheet structure, the fourth embodiment has a three-layer clad tube sheet structure. There is.

In each embodiment shown in FIG. 1, each cooling channel (13α)
(13A) (t3C) (tad, z3d) is formed up to the end of the tubesheet, but a frame (not shown) can also be simultaneously bonded to the outer periphery of the tubesheet by diffusion bonding. For medium mats, the materials are heated to a temperature below their melting point in an inert gas, and an appropriate stress is applied to bond them by diffusion, but small items are heated in a furnace, and large items are sealed with gold around them, and only the joint surfaces are vacuum-bonded. Alternatively, solid phase bonding can be easily performed by means such as indirect heating in an inert gas atmosphere.
) T-through) form vertical and horizontal water channels, and cooling water flows vertically and horizontally.

In each of the above embodiments, the protrusion group is provided on the tube plate main member and the intermediate plate eD side, but it is also possible to provide the protrusion group on the surface plate itη side, and the protrusion group is provided on the tube plate to the nine pipe holes α. In addition to inserting the end of the tube (2) into the tube hole I as shown in the figure, there is also a method of fitting the end of the tube (2) into a part of the tube hole (14). This can be done by inserting and welding, or by protruding a part of the tube sheet and welding it against the tube, which is an internal welding method.

(Operations and Effects of the Invention) As mentioned above, the present invention has a tube plate main body (a surface plate on 10 sides).
11) (The hole is the intermediate plate I21) All protrusions (12α
, 12b.

12C, 12d, 22d), and cooling channels (13α) are connected by the projections between the main tube sheet QQ and the surface plate (11).

13b, 13C, 13d, 23d) are formed in the tubesheet, a complex cooling channel is formed with high precision between the main body of the tubesheet and the surface plate, and it is possible to reduce the flow of process fluids such as D2 water supply. By circulating the high temperature fluid through the cooling channels, the cooling performance and reliability of the tubesheet are significantly enhanced, and damages such as decarburization, hydrogen attack, nitridation, and stress corrosion cracking are extremely effectively and significantly reduced. This makes it possible to reduce the grade of the tube sheet material, thereby significantly improving the integrity of the P tube sheet and the operational reliability of the heat exchanger.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

FIG. 1(A) is a perspective view and longitudinal sectional view of a member showing the first embodiment of the present invention, FIG. 1(B) is a perspective view and longitudinal sectional view of the member showing the second embodiment of the invention, and FIG. 1(C) 1(D) is a perspective view and longitudinal sectional view of a member showing the third embodiment, FIG. 1(D) is a perspective view and longitudinal sectional view of a member showing the fourth embodiment, FIG. The figure is a longitudinal sectional view showing another conventional example. 10: Main tube plate 1: Surface plate 12α, 12A, 12C, 12d, 22d:
Protrusions 13α, 13, 6.13C, 13d, 23d: Cooling waterway Sub-agent Patent attorney Shige Okamoto 2 other people

Claims (1)

[Claims] A surface plate is joined to the main surface of the tube plate through a group of protrusions,
A multi-tube heat exchanger characterized in that the tube plate is configured with a cooling channel formed by the group of protrusions between the tube plate main body and the surface plate.