CN211854974U

CN211854974U - Fixed tube plate heat exchanger

Info

Publication number: CN211854974U
Application number: CN201922435393.XU
Authority: CN
Inventors: 邓敏; 何楷平; 毛林; 赵华; 何兵
Original assignee: Yibin Tianyuan Haifeng Hetai Co ltd
Current assignee: Yibin Tianyuan Haifeng Hetai Co ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-11-03
Anticipated expiration: 2029-12-30

Abstract

The utility model discloses a can prevent fixed tube sheet heat exchanger of welding seam corruption between medium and heat exchange tube and the tube sheet in fixed tube sheet heat exchanger shell side, this heat exchanger include the tube sheet and with tube sheet welded heat exchange tube, the welding seam is located the tube side of tube sheet, the shell side of tube sheet is arranged and is had separation shell side medium flow direction the coating of welding seam, the part that the heat exchange tube is located the tube sheet have the reducing design, are close to the heat exchange tube external diameter that tube sheet both sides terminal surface position department was located promptly and are less than the heat exchange tube external diameter that is located tube sheet intermediate position department, the coating extends the surface between the inner wall that covers to the outer wall of heat exchange tube and tube sheet. The utility model discloses fill up the clearance that is full of between heat transfer pipe and tube sheet with coating material or excessive and cover the tube sheet internal surface a little, form the one deck protection film, prevent shell side medium and welding seam contact, prevent corrosion failure, prolong the life of heat exchanger.

Description

Fixed tube plate heat exchanger

Technical Field

The utility model relates to a fixed tube sheet heat exchanger's welding seam protection.

Background

At present, the connection of a heat exchange tube and a tube plate of a fixed tube plate heat exchanger mainly adopts three types of intensity expanded joint, intensity welding and expanded welding.

In the use process of chemical production, the three connection types of the fixed tube plate heat exchanger are most commonly used in combination of strength welding and expansion welding. The failure of the welding seam between the heat exchange tube and the tube plate accounts for the vast majority of the failure and scrapping reasons of all heat exchangers. Therefore, the welding quality and the stability of the welding seam in the use process are the key reasons influencing the service life of the fixed tube plate heat exchanger.

The shell side medium of the heat exchanger is in acid, alkali, strong oxidation and other characteristics inevitably in the existing chemical production, and the medium with the characteristics is contacted with a welding seam through a gap between a tube side heat exchange tube and a tube plate to form the phenomena of point corrosion, stress corrosion, intergranular corrosion, electrolytic corrosion and the like, so that the welding seam is failed in a large area, the medium leaks through the way, and the service life is reduced until the welding seam is scrapped. Medium corrosion occurs on the tube pass side, and a plurality of treatment methods are relatively available in the production practice; however, corrosion occurs on the shell side, and the corrosion is usually avoided only by adopting selected materials. The reason is that the tube plate heat exchanger is fixed, the shell side is usually assembled by welding, and the disassembly is only broken and removed.

Therefore, after the medium is contacted with the welding seam through the gap between the shell side heat exchange tube and the tube plate to generate local corrosion, the problem is solved. The former solution is to repair the weld on the tube side after the corrosion occurs. There is no method to prevent or prevent this from occurring in advance.

By way of example, the alkali preheater used in production by the applicant is a fixed tube-plate heat exchanger, and the tube-pass and shell-pass circulating media are high-temperature alkali, and the alkali products have wide sources and different qualities, wherein the alkali products have high time bottoms when containing chloride ions; therefore, austenitic stainless steel equipment cannot be selected, and carbon steel equipment is finally selected according to cost performance. Therefore, the corrosion phenomenon of the welding seam between the heat exchange tube and the tube plate frequently occurs, the welding is frequently repaired, and the production is greatly influenced by frequent parking and maintenance. Through analysis, the alkali is shell pass low-temperature alkali, the alkali with high relative temperature is formed after heat exchange and is evaporated, the alkali enters a gap between a shell pass heat exchange tube and a tube plate, meanwhile, the tube plate of the heat exchanger is a high-temperature conductor, and when the alkali steam with high relative temperature is heated again in the gap and is contacted with a welding seam, the phenomenon of very serious alkali corrosion occurs. The emphasis shows that the heat exchanger is made of materials completely meeting the requirements of production and use from the working condition. (Note: different temperatures of alkali, different corrosion rates for the same metal, refer to the corrosion data handbook).

SUMMERY OF THE UTILITY MODEL

In order to prevent medium and welding seam contact in the fixed tube sheet heat exchanger shell side, form and corrode to equipment failure damages and leads to the shut down, the utility model provides a fixed tube sheet heat exchanger carries out the preliminary treatment earlier to this heat exchanger tube sheet welding seam part, prevents that the medium through the shell side from reacing the welding seam and arousing the corruption.

The utility model provides a technical scheme that its technical problem adopted is: the fixed tube plate heat exchanger comprises a tube plate and a heat exchange tube welded with the tube plate, wherein a welding seam is positioned on the tube side of the tube plate, and a coating for blocking a medium on the shell side from flowing to the welding seam is arranged on the shell side of the tube plate.

The coating is a glass flake coating.

The part of the heat exchange tube, which is positioned in the tube plate, is provided with a reducing design, namely the outer diameter of the heat exchange tube, which is close to the end surfaces on the two sides of the tube plate, is smaller than that of the heat exchange tube, which is positioned in the middle of the tube plate, and the coating extends to cover the surface between the outer wall of the heat exchange tube and the inner wall of the tube plate.

The utility model has the advantages that: the coating material is used in the shell side of the heat exchanger to fill the gap between the heat exchange tubes and the tube plates or slightly excessive to cover the inner surface of the tube plate to form a layer of protective film, so that the contact between the shell side medium and the welding seam is prevented, the corrosion failure is prevented, and the service life of the heat exchanger is prolonged.

Drawings

Fig. 1 is a partial schematic view of the fixed tube plate heat exchanger of the present invention.

Fig. 2 is a partially enlarged view of a portion K in fig. 1.

Labeled as: 1-heat exchange tube, 2-coating, 3-tube plate, 4-welding seam.

Detailed Description

The present invention will be further explained with reference to the drawings and examples.

As shown in fig. 1 and 2, the fixed tube plate heat exchanger of the present invention comprises a tube plate 3 and a heat exchange tube 1 welded to the tube plate 3, wherein a welding seam 4 connecting the two is located on the tube side of the tube plate, and a coating 2 blocking the medium flow direction on the shell side of the tube plate 3 is disposed on the shell side of the tube plate 4. Through the setting of coating, changed current fixed tube sheet heat exchanger medium, tube sheet joint operating condition form, made harsh medium direct contact mode be changed into isolated mode, the coating material is as the buffer layer, only under the impaired condition of coating, the welding seam just probably corrodes, has effectively prolonged the life or the maintenance cycle of heat exchanger.

As shown in fig. 2, the heat exchange tube 1 has a variable diameter design at the inner side of the tube plate 3, i.e. the outer diameter of the heat exchange tube at the positions close to the end faces at the two sides of the tube plate 3 is smaller than the outer diameter of the heat exchange tube at the middle position of the tube plate 3, and the coating 2 extends to cover the surface between the outer wall of the heat exchange tube 1 and the inner wall of the tube plate 2. The design can effectively reduce the use amount of coating materials and improve the adhesion stability of the coating.

Example (b):

as shown in fig. 1 and 2, the utility model discloses a fixed tube sheet heat exchanger include tube sheet 3 and with tube sheet 3 welded heat exchange tube 1, connect the welding seam 4 of the two to be located the tube side of tube sheet, the part that heat exchange tube 1 is located tube sheet 3 has the reducing design, is less than the heat exchange tube external diameter that is located tube sheet 3 intermediate position department near the heat exchange tube external diameter of tube sheet 3 both sides terminal surface position department promptly, and the shell side of tube sheet 3 is arranged the separation shell side medium flow direction the coating 2 of welding seam 4, coating 2 extend to cover to the surface between the outer wall of heat exchange tube 1 and the inner wall of tube sheet 2.

The specific implementation mode of the structure is as follows: after the fixed tube plate heat exchanger equipment is manufactured, coating solution is prepared, the shell side of the heat exchanger is upright in a side-up mode, the prepared coating solution with a certain volume is injected through a hose, and the fixed tube plate heat exchanger equipment is naturally dried. The coating for blocking the medium on the shell side from flowing to the welding seam can be formed in the shell side of the equipment, the volume of the coating solution can be filled in the gap between the heat exchange tube and the tube plate or slightly excessive, and a protective film is formed on the surface of the shell side in the tube plate in the case of excessive volume.

The use of the coating can prolong the overhaul period or the service life of the heat exchanger, the effect is good, and the defect is that a small part of heat exchange area is inevitably sacrificed.

The tube side of the tube sheet may also be provided with a coating to block flow of the tube side media to the weld. Whether the coating is arranged depends on whether further adverse effects on the heat exchange area are taken into account.

The coating material is selected and selected according to the application conditions of the actual heat exchanger, mainly according to the properties of the medium, and the requirements of the fixed tube plate heat exchanger on the use working condition, the medium characteristics, the equipment structure and the like are met. The technology of coating materials, for example, graphene-containing product coatings, is changing day by day.

For the heat exchanger with high temperature alkali as medium, glass flake coating is preferably selected, and the effect is better.

Claims

1. Fixed tube sheet heat exchanger, including tube sheet (3) and with tube sheet (3) welded heat exchange tube (1), connect welding seam (4) of the two to be located the tube side of tube sheet, characterized by: and a coating (2) for blocking the medium on the shell side from flowing to the welding seam (4) is arranged on the shell side of the tube plate (3).

2. The fixed tube sheet heat exchanger of claim 1 wherein: the coating (2) is a glass flake coating.

3. The fixed tube sheet heat exchanger of claim 1 wherein: the heat exchange tube (1) is located the part of tube sheet (3) and has the reducing design, is close to the heat exchange tube external diameter that tube sheet (3) both sides terminal surface position department was located promptly and is less than the heat exchange tube external diameter that is located tube sheet (3) intermediate position department, coating (2) extend the surface between the inner wall that covers to the outer wall of heat exchange tube (1) and tube sheet (3).