Does the minimum thickness of the cylinder include the shell of the kettle-type reboiler?
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GB/T 151-2014, Table 7-1 in Heat Exchangers (as shown in the screenshot), specifies the minimum thickness of the cylinder (note that this is the nominal thickness). When the heat exchanger is of the kettle-type reboiler design, it is common for some people to have questions regarding the thickness of the shell-side cylinder for this type of heat exchanger; that is, 1. Is it necessary to follow Table 7-1 for the thickness of the shell-side cylinder in a kettle-type reboiler? 2. If it is necessary to follow Table 7-1, how should the minimum thickness of the cylinder be determined? Fellow forum members, share your opinions; the answers can be seen in the replies. Answer: 1. It is necessary to follow Table 7-1 ； 2. Note that when selecting the minimum thickness of the cylinder according to Table 7-1, the header indicates “DN”, which refers to the nominal diameter; therefore, the minimum thickness of the shell in the shell side of a kettle-type reboiler is determined based on the diameter of the tube side. The definition of nominal diameter and special notes on kettle-type reboilers are provided in the definition section at 3.1; see the screenshot: Did you answer correctly? ^O^
A kettle-type reboiler has its nominal diameter determined by the inner or outer diameter of the tube sheet; the choice of tube sheet can be made as long as the strength calculations are satisfied. It seems that the shell-side cylinder doesn’t have to follow the 7-1 standard, just like the guide cylinder – it’s not necessary for it to follow the 7-1 standard either
1. The thickness of the shell cylinder of the kettle-type reboiler does not need to follow Table 7-1. 2. The minimum thickness of the cylinder for the tube bundle-related sections can be determined according to Table 7-1.
In practice, we do not follow Table 7-1 when creating the drawings; otherwise, the wall thickness would be excessively large. Generally, kettle-type reboilers are designed to withstand negative pressure, so such a thick wall thickness is not necessary at all. . .
I misinterpreted the meaning; I still thought that the wall thickness specified in Table 7-1 applied to the entire shell side. If it’s only the section of the small cylindrical shell side where the heat exchange tubes are located, then the wall thickness from Table 7-1 should be used.
Well, if you don’t look closely, it’s easy to misunderstand. It’s a bit wordy. In simple terms, the shell of the shell side does not have to comply with the requirements in Table 7-1, but it must not be thinner than the minimum wall thickness specified for the tube side cylinder.