Engineering calculation method of flexible thin tube sheet

Abstract

The invention discloses an engineering calculation method of a flexible thin tube sheet, comprising the following steps: determining the wall temperature of a heat exchange tube and the design temperature of a channel box; according to the technological condition, optimizing the tube pitch of key structural parameter and the wall thickness of the heat exchange tube; analyzing and processing a calculation result; if secondary stress is out of limit under the combined action of the tube, shell side pressure and temperature difference load, forbidding considering the calculation result of nonexistent operation working condition; and if the primary stress is out of limit under the combined action of the tube and the shell side pressure, converting the secondary stress into the primary stress for controlling. The invention has the positive effect on making up the shortcomings because of adopting two calculation methods for designing flexible thin tube sheets for a long term, i.e. the defects of limited applicable range or long consumed calculation time, high calculation cost and complex calculation process. The method has wide applicable range, high calculation speed, simple calculation process and safe and reliable calculation result and conforms to the requirements of national energy saving and consumption reduction as well as cost saving for enterprises.

Description

technical field [0001] The invention relates to an engineering calculation method of a flexible thin tube plate. Background technique [0002] As waste heat recovery equipment for generating steam, steam generators are widely used in various production devices, and play an extremely important role in saving energy and reducing consumption and obtaining economic benefits for each production device. It has a variety of structural types, but in petrochemical production equipment, because the temperature, pressure, and flow rate are not too high, the structural type of the tubular steam generator is the majority. At present, there are two typical structures of shell-and-tube steam generators in China: the traditional structure of thick tube plate and shell-side expansion joint, and the flexible thin tube plate structure evolved from the device imported from Germany in the early 1980s. [0003] The main advantages of the traditional structure are simple structure, easy material ...

AI Technical Summary

Problems solved by technology

[0003] The main advantages of the traditional structure are simple structure, easy material acquisition, easy processing, and convenient installation and maintenance. The disadvantage is that it has poor adaptability to the temperature difference change of the shell side during the start-up process, and the connection joint between the tube and the tube sheet is prone to failure; the flexible thin tube sheet structure In addition to the advantages of the traditional structure, it also has the advantages of strong adaptability to the temperature difference change of the tube and shell side during operation, and the advantages of safe and reliable operation for a long period of time.

[0004] For the tube-sheet calculation of traditional structures, there are mature and reliable standards at home and abroad (such as: GB151 in my country, TEMA in the United States, PD5500 in the United Kingdom, AD in Germany, CDDAP in France, GOST in the former Soviet Union, JIS in Japan, etc.) and method for adoption, and for the calculation of flexible thin tube sheets, there are currently two common methods, that is, according to the German AD code or the finite element stress analysis method, but the fly in the ointment of these two methods is: the German AD code is only based on The local bending stress, which occupies a secondary position in the tube sheet stress, is calculated as the tube sheet stress, and its applicable range is limited, that is, it is not suitable for the case where there is a difference in thermal expansion between the shell side cylinder and the heat exchange tube; the stress analysis of finite element The method has the characteristics of accurate calculation results and unlimited scope of application, but the calculation time consumed is too long, the calculation cost is too high, the calculation process is cumbersome, and it is difficult to meet the requirements of most owners for the design progress