Selection method of pipe plugging for shell-sand-tube heat exchanger

Abstract

The invention relates to a selection method of pipe plugging for a shell-sand-tube heat exchanger and relates to the field of detection and evaluation of the shell-sand-tube heat exchangers in petrochemical industry. The method disclosed by the invention selects leakage heat exchange tubes based on a conventional hydrostatic test, and selects heat exchange tubes which are likely to leak within a next operational cycle by NDT (non destructive testing) and integrity assessment technologies. The NDT technology is used for finding out present defect sizes of the heat exchange tubes containing detects, the integrity assessment technology is used for obtaining a present maximum allowed defect size of the heat exchange tubes, and the maximum allowed defect size is a difference between a critical failure defect size and defect increment and NDT uncertainty in the next operational cycle. If the present defect size is smaller than the maximum allowed defect size, pipe plugging does not need to be implemented; otherwise, the pipe plugging needs to be implemented. The method disclosed by the invention can be implemented in the process of maintenance for selecting relatively dangerous heat exchange tubes and further plugging the tubes, thus effectively reducing temporary stop times of the heat exchanger in the operational cycle and then reducing enterprise accident potentials and improving enterprise economic benefits.

Description

technical field [0001] The invention relates to a method for selecting blocked tubes of the shell-and-tube heat exchanger when the shell-and-tube heat exchanger is overhauled, and belongs to the field of detection and evaluation of the shell-and-tube heat exchanger in the petrochemical industry. Background technique [0002] Shell-and-tube heat exchangers are the most widely used heat exchangers in petrochemical enterprises, accounting for about 25% of the total equipment in enterprises. The heat exchange tube is the part with the worst service condition of the shell and tube heat exchanger, and it often leaks due to corrosion (inner leakage of the heat exchanger). Leakage of heat exchange tubes will seriously affect product quality, and even cause major safety accidents. For example, on July 16, 2011, a heat exchanger of a 10 million-ton atmospheric and vacuum distillation unit in the plant of PetroChina Dalian Petrochemical Company leaked and caused a fire, causing Theref...

AI Technical Summary

Problems solved by technology

This method is simple and easy, and the detection speed is fast, but it can only find the heat exchange tubes that have leaked during the maintenance. For those heat exchange tubes that did not leak during the hydraulic test but have serious defects, it is impossible to find o...

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