U-Tube Exchanger

[Angsi]

Equipment: TEMA S&T Heat Exchanger, BEU type.
Design: ASME Div 1/TEMA
Service: Crude Oil Cooler
Location: Offshore Platform
Tubeside, 316L, Shell side CS (Cooling water)
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We plan to rerate an existing S&T Hex which has already been operating for a period of close to 3 years. The idea is to increase the design temperature of the exchanger from 115 deg to 145 deg C.

Steps:
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1. Take measurement to acertain remaning thickness (UT, etc).
2. Review calc to determine if the increase in temperature can be accomodated by the present design
3. If required and depending upon the magnitude of this mod, removal of it to the fab shop might be necessary. Then the complete mods, design calcs and rehydrotest will be required I guess.
4. If the current mech design can accomodate the change, the design calcs needs to certification and the nameplate rating has to be cahnged and the equipment rehydrotested again.

The question is, can anyone here tell me based on past their experience, how the change in temperature will affect the mechanical design of the following comp:

1. Tube (SS) - Guess the tube thickness will not be affected.
2. Shell - Un affected
3. Tubesheet - ??
4. Bolts - ???
5. Other comps - ??

Thanks in advance.
2.

 

[pve5]

Before I could answer your questions,please confirm the following :

1. What is original edition of ASME Code for the exchanger. 2. What are the design conditions for shell side and tube side.
3. Is material of tubesheet solid SS or CS with SS weld overlay.
4. How many passes on tube side

 

[Angsi]

pve5,

The answers are:

1. Div I Year 2000 Edition
2. Tubesheet is CS + SS Overlay
3. Its a U-Tube bundle with a single pass partition plate on the channel side.

Thanks.

 

[pve5]

Angsi,

1. Since this is a U tube exchanger, tubesheet thickness will not change. Max. allowable stresses at 115C and 145C are same.
2. Channel / Channel cover material , if CS with SS 304L cladding , then no change in thickness required.

3.There would not be any change in bolting.

Trust above answer your questions