Tube sheet design issues
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Dear friends, there is a heat exchanger: in the shell side, water at 7 degrees Celsius flows, with a design pressure of 0.6 MPa and an operating pressure of 0.4 MPa; in the tube side, the VCM gas is used as the fluid (it is flammable and explosive, with moderate hazard), with a design pressure of 0.8 MPa and an operating pressure of 0.5 MPa. The design temperature is 80 degrees Celsius, while the operating temperatures are 45/20 degrees Celsius. The material of the tube sheet is 16MnⅢ with a thickness of 50 mm. Is it necessary to use forged 16MnⅢ material? Why?
I don’t think it’s necessary; the pressure isn’t high, and the medium isn’t highly hazardous or of a higher risk category, so level 2 should be sufficient.
Can sheets be used? For well-known reasons, forged parts are not easy to find
Well, as the saying goes, different people have different opinions on this matter. It can’t be said whether it’s right or wrong; provided that the standard specifications are met, it is acceptable to take economic considerations into account to a certain extent. However, while considering cost-effectiveness, some safeguard measures need to be put in place. For example, would using sheet material work for this? Sure, it works. 50mm thick – not too thick – UT testing is added to prevent delamination. Moreover, the smelting capabilities of steel mills in China are currently quite high; many experts often claim that China’s steel mills are among the best in the world! However, it cannot be considered from just this one aspect; the structural design also needs to be taken into account, such as the connection points between the shell side cylinder and the tube sheet, and whether there are shoulder structures or not.
There are also the connection types between the heat exchange tubes and the tube sheet
According to the requirements of new plate 151, plates can be used; however, for tube sheets with shoulders and internal holes that are welded, there are special requirements, and it is also necessary to ensure properties in the thickness direction.
Forgings are preferable first, but Grade III is not necessary; the pressure is not high, and the medium is not highly hazardous or of a higher category. Generally, level III is still more expensive; cost considerations must be taken into account.
Thank you all. It’s a regular heat exchanger; the heat exchange tubes and tube sheets require strong welding along with expansion joints.
Is it your company’s own project or one brought in from outside? If it’s an external project, it is usually required by the unified design specifications set by the contractor or the client
SH 3075-2009
Sinopec’s project requires that the tube sheets be made of forgings, grade III or higher.