Embedded deep-hole welding structure for flexible tube plate of waste heat boiler

Abstract

The invention provides an embedded deep-hole welding structure for a flexible tube plate of a waste heat boiler, and relates to the technical field of boiler equipment in the petroleum and coal chemical field. The embedded deep-hole welding structure comprises a ring-shaped reinforcing lug boss which is arranged on the inner tube wall of the flexible tube plate and raised outward. The ring-shaped reinforcing lug boss is welded to the outer wall of a heat exchange tube through deep-hole welding, so that not only can a tube head seal between the flexible tube plate and the heat exchange tube be directly cooled by shell-side water and the temperature of the tube head seal be effectively reduced, but also a welding gap between the flexible tube plate and the heat exchange tube can be eliminated. Accordingly, the tube head weld can be protected from high-temperature failure and gap-corrosion failure, and then the running cycle of the waste heat boiler can be prolonged.

Description

technical field [0001] The invention relates to the technical field of boiler equipment in the field of petroleum and coal chemical industry, in particular to an embedded deep hole welded structure of a flexible tube plate of a waste heat boiler. Background technique [0002] In the fields of petroleum refining, chemical industry, coal chemical industry, etc., the technical research on energy saving and emission reduction is increasing. Waste heat boiler is the most widely used equipment in heat recovery technology. The research and promotion of new structure waste heat boiler will be Plays an extremely important role in energy saving. [0003] At present, the connection between the tube plate and the heat exchange tube of the waste heat boiler is the core part of the whole waste heat boiler, and it is also the weakest part. A large number of failures of the waste heat boiler occur in this part. The connection structure of this part is generally welded or welded. Expansion ...

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Problems solved by technology

[0003] At present, the connection between the tube plate and the heat exchange tube of the waste heat boiler is the core part of the whole waste heat boiler, and it is also the weakest part. A large number of failures of the waste heat boiler occur in this part. The connection structure of this part is generally welded or welded. Expansion joints, but with conventional welded constructions (such as figure 1 As shown), the formed tube head weld 30 is located on the side of the high-temperature medium, and the tube head weld 30 will generate thermal stress due to the heating of the high-temperature medium, and these thermal stresses may cause stress corrosion and cracking, leading to high-temperature failure, and the tube sheet 10 There is a welding gap between the heat exchange tube and the heat exchange tube 20, which is likely to cause crevice corrosion failure; if a conventional expansion joint structure is adopted, there is a large residual stress due to expansion joint deformation, which is prone to stress corrosion, and when the operating temperature is high, the material The creep of the expansion joint will relax the residual stress, which will cause the joint to loosen or fall off, resulting in leakage. It can be seen that neither the conventional welded structure nor the conventional expansion joint structure is suitable for high temperature environments, and due to the process at the inlet end of the waste heat boiler Gas can be as high as 1200°C. Under such high temperature conditions, conventional welded structures and expansion joint structures are prone to high temperature failure or crevice corrosion failure, which greatly reduces the operating cycle of the waste heat boiler. Therefore, it is necessary to design a new connection structure to realize waste heat. Boiler tube sheet and heat exchange tube connection

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