When placing a shell-and-tube heat exchanger with a non-removable tube bundle such as a lube oil cooler with fixed tube sheets into service, to avoid thermal shock what statement represents the correct operating procedure?
• Thermal shock in shell-and-tube heat exchangers with fixed tube sheets (non-removable tube bundle) • Which side is normally hotter: lube oil or cooling water, and how metals expand when heated • How uneven / sudden cooling or heating can stress tube-to-tube-sheet joints
• First decide which fluid (lube oil or cooling water) is normally at the higher temperature when putting the cooler into service. • Think about what happens to metal parts if a cold fluid suddenly hits very hot tubes or tube sheets—does that increase or decrease thermal stress? • Ask yourself: do you want the metal to be warmed up more uniformly first, or suddenly cooled/heated from one side?
• Identify which fluid is normally hot and which is cold in a lube oil cooler service. • Decide which fluid should be started first and gradually so metal temperature changes are gentle, not abrupt. • Eliminate any option that calls for immediate full flow of both fluids without gradual temperature equalization.
No comments yet
Be the first to share your thoughts!