Because of the temperature difference between the fluids inside and outside the tubes in a shell-and-tube heat exchanger, the temperature of the shell and the tube bundle also differs. If the temperature difference is large, significant thermal stress will be generated within the heat exchanger, leading to tube bending, breakage, or even pull-out from the tube sheet. Therefore, when the temperature difference between the tube bundle and the shell exceeds 50°C, appropriate compensation measures must be taken to eliminate or reduce thermal stress. Below is a brief introduction to the key points for installing shell-and-tube heat exchangers.
1. The heat exchanger should undergo a hydrostatic test at 1.5 times its maximum operating pressure. For the steam section, the pressure should be no less than the steam supply pressure plus 0.3 MPa; for the hot water section, it should be no less than 0.4 MPa. Maintain the pressure at the test pressure for 10 minutes without pressure drop.
2. Sufficient space should be left at the front end of the shell-and-tube heat exchanger for tube bundle removal. That is, the distance between the end caps and the wall or roof should not be less than the length of the shell-and-tube heat exchanger. The clear width of the operating passage should not be less than 0.8 m.
3. The installation height of all valves and instruments should facilitate operation and observation.
4. The vertical clearance between the highest point of the upper accessories of the heater and the lowest point of the building structure should meet the requirements for installation and inspection, and should not be less than 0.2m.
The above are the key points for the installation of shell-and-tube heat exchangers. We hope this information is helpful.