Expansion Joint - BEM type Heat exchanger
Expansion Joint - BEM type Heat exchanger
(OP)
Dear all
I have to do a preliminary mech. design of a BEM(TEMA) type heatexchanger (Vertical - Fixed tube sheets). The exchanger shall be on Lugs on RCC framed structure. Would like to know the criteria for requirement of Expansion joints for the design conditions. Is an Expansion joint required on the shell. Design parameters are as below:
Shell MOC - ASTM A517 Gr 70
Tube MOC - SS316
Shell side
Design Temperature(deg.C) - 265 (In) & 194(Out)
Design Pressure (kg/sqcm) - 13.00
Tube Side
Design Temperature(deg.C) - 133 (In) & 149(Out)
Design Pressure (kg/sqcm) - 11.00
Maximum Axial Differential Thermal Expansion between Shell and Tubes-Tube has higher Thermal growth (Exp. Jt. Extension) : +0.179 mm
Kindly give your experienced opinion on whether expansion joints are required ?
Thanking you all in anticipation
I have to do a preliminary mech. design of a BEM(TEMA) type heatexchanger (Vertical - Fixed tube sheets). The exchanger shall be on Lugs on RCC framed structure. Would like to know the criteria for requirement of Expansion joints for the design conditions. Is an Expansion joint required on the shell. Design parameters are as below:
Shell MOC - ASTM A517 Gr 70
Tube MOC - SS316
Shell side
Design Temperature(deg.C) - 265 (In) & 194(Out)
Design Pressure (kg/sqcm) - 13.00
Tube Side
Design Temperature(deg.C) - 133 (In) & 149(Out)
Design Pressure (kg/sqcm) - 11.00
Maximum Axial Differential Thermal Expansion between Shell and Tubes-Tube has higher Thermal growth (Exp. Jt. Extension) : +0.179 mm
Kindly give your experienced opinion on whether expansion joints are required ?
Thanking you all in anticipation





RE: Expansion Joint - BEM type Heat exchanger
Still, it should be confirmed per Part UHX, or other applicable Code, for all operating cases to be encountered.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Expansion Joint - BEM type Heat exchanger
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Expansion Joint - BEM type Heat exchanger
Cheers,
RE: Expansion Joint - BEM type Heat exchanger
Setting the design temps the same for both sides may not eliminate the need for this expansion joint, if you think this is required for the thermally induced differential stresses between shell and tubeside.
Diff thermal stress would be highest at startup if one side were to be warmed up to max op temp while the other side is still at lowest ambient temp.
RE: Expansion Joint - BEM type Heat exchanger
As a thumb rule, if you are getting abnormal tube sheet thickness then you have to go for expansion joints.
RE: Expansion Joint - BEM type Heat exchanger
This is not true for most heat exchangers. The tubeside and shellside can have very different design temperatures. Common elements however should be designed in accordance with the highest temperature to which it is exposed.
So for example on a typical BEM exchanger you could have:
RE: Expansion Joint - BEM type Heat exchanger
Material strength properties are evaluated at the design temps, as per marty007, previous.
Differential thermal expansion is evaluated at operating temps, usually the mean metal temps (MMT) which may be a simple average of the inlet / outlet temps for each side, or perhaps something more "accurate" pulled from the rating data.
Strength properties may be evaluated at the MMT's at the designers' option.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Expansion Joint - BEM type Heat exchanger
RE: Expansion Joint - BEM type Heat exchanger
Many thanx for all your feedback,Members! I am trying to do a UHX design.
MrBTU,
Tube length = 4500mm, Single segmental baffles,26.13%cut, 450mm spacing, first baffle at 870 mm from inlet.
Tube-to-Tubesheet is expanded & strengthwelded.
Shell side medium - Steam
Tube side medium - Hydrocarbon (Kerosene)
Thanks
RE: Expansion Joint - BEM type Heat exchanger
The process - thermal design engineer should be asked for reasoning for this current selection.
RE: Expansion Joint - BEM type Heat exchanger
Thanx for your feedback. The process engineer would be definitely asked this question.