Dear Experts, I have seen a namepla 3

[ALA445]

Dear Experts, I have seen a nameplate on shell and tube type heat exchanger designed on ASME Code with all parameters same for shell as well as tube bundle like design pressure, design temperature, MAWP, Hydrostatic test pressure etc. What is the use of exchanger if all parameters are same for shell and tube side. Thanks for your input please.

 

[Latexman]

There is nothing wrong with a S&T heat exchanger with the same MAWP, MAWT, material of construction, etc. on both shell and tube sides. It is correct. It meets Code. It will transfer heat.

What problem do you have with this?

Good Luck,
Latexman

 

[MJCronin]

It is important to remember that the ASME Nameplate contains DESIGN VALUES for these important parameters.

The HX may be intended to seldom or never operate anywhere near these values.

I do not understand the problem with this either...

MJCronin
Sr. Process Engineer

 

[saplanti]

In case the heat exchanger is in operation you need to measure pressure and temperature at inlet and outlet of both heating and heated fluids (shell and tube sides) and flow rates. This will give you information about the process.

The pressure and temperature for design and test pressure may be given on the name plate which may not reflect operation condition. I have seen some name plates give the operation conditions as well, they were very useful to understand the operation without seeing drawings.

Sometimes, the measured pressure and temperature and perhaps flow rate can be different due to fouling in the tube surfaces.

Therefore I suggest you to find drawings first, and PID if you need further information.

 

[BronYrAur]

Those numbers refer to the allowable pressures and temperatures of the shell and tube materials. design pressure, working pressure, etc.

They say absolutely nothing about the process. They contain no flow or differential temperature information that would provide you with an amount of heat transfer. I have never seen a heat exchanger tag that containes any such performance data. It is very frustrating when you are asked to replace such a piece of equipment. The end user quite often does not have the load information. Short of gathering flow and delta-T info or steam flow rate if it is steam, take good physical measurements of the heat exchanger. length, diameter, pipe connection size, etc. Your vendor can probably make a reasonable selection with that information.

 

[Christine74]

Having identical design conditions on both the shell side and the tube side *hints* (but certainly doesn't prove conclusively) that it might have been an "off-the-shelf" design. Small shell & tube heat exchangers can be purchased pre-fabricated with generic design conditions such as 100 psi at 500F with -20F MDMT and a 1/16" corrosion allowance.

Another possibility is that it is a Feed/Effluent exchanger where the same process fluid flows through both sides of the exchanger. Or it could just be a coincidence.


-Christine

 

[LittleInch]

Or someone decided that the tube contents if a tube ruptured shouldn't result in a shell overpressure.

Often you need to add bursting discs to prevent the shell rupturing and that isn't always acceptable.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Christine74]

Usually for tube rupture scenarios you only need to rate the low-pressure side of the exchanger to 1 / hydrotest multiplier of the high-pressure side. So if the exchanger is designed per ASME Section VIII Div 1., the low-pressure side of the exchanger is designed to 77% of high-pressure side and the it will be hydrotested at a minimum of 1.3X the MAWP. 1.3 times 0.77 is 1.0, so the low-pressure side will have been hydrotested at the maximum pressure it could possibly see in the event of a tube rupture.

Not perfect because this does not account for the fact that the hydrotest takes place in the uncorroded condition, but it's close enough to have been incorporated into API RP 521.


-Christine

 

[LittleInch]

I think I would prefer the full MAWP rating to be the same myself, but that's interesting to know that.

Often the high / low pressure ratings of tube and shell is an order of magnitude.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.