Regarding the design pressure of shell and tube heat exchangers
Thread Content
A problem arises in the design: the operating pressure on the tube side is 0.35 MPaG, while the operating pressure on the shell side is 2 MPaG. If the design pressure for the shell side is set at 2.2 MPaG, then what determines the design pressure for the tube side under such conditions? Is it appropriate to set it at 0.6 MpaG as is standard? Was it said that the shell-side pressure damages the tube from the outside in? My skills are limited; please forgive me if the questions are too simple
This post was last edited by kaminocmyhc on 2011-4-4 at 14:58. Generally, high pressure is applied to the tube side while low pressure is applied to the shell side. To reduce equipment costs, in special cases high pressure may be applied to the shell side. Given the large pressure difference in your operating conditions, it is necessary to consider the tube’s ability to withstand external pressure; an internal pressure of 2.0 MPa is likely not sufficient to ensure operational safety
This device is a special case; the high-pressure side is on the shell side. I didn’t fully understand the answer given on the second floor
Based on the requirements, the design pressure on the tube side of this heat exchanger can be set at 0.6 MPa; however, the heat exchange tubes need to be checked for external pressure, and the wall thickness should be taken as the higher of the two values.
1. The operating pressure on the shell side is 2 MPaG; the design pressure for the shell side must take into account factors such as the operating temperature and the test pressure for equipment strength. It is necessary to conduct further calculations to determine whether 2.2 MPaG is appropriate. 2. For the tube side, due to the large difference between internal and external pressures, it is necessary to consider whether the strength of the tube bundle can meet the requirements imposed by the external pressure. Generally, a design pressure can be determined based on the internal pressure; after taking factors such as temperature into account, the appropriate pipe material is selected, and then a strength check is performed considering the external pressure until the requirements are met.
A design pressure of 0.6 MPa for the low-pressure side is sufficient; however, it is necessary to calculate the strength of the low-pressure side when evaluating the equipment. I prefer to consider the situation where there is no fluid in either side during the equipment calculations, as this makes things safer.