High Pressure Heat Exchanger Channel Barrel Thickness calculation

[DK44]

In a High Pressure Hear Exchanger ( Design pressure = 159 barg) the cylindrical Channel barrel is directly bolted to the End cover.
Required thickness as per ASME Sec VIII Div 1, UG-27 is 37 mm. Since it is to be directly bolted to end cover the thickness is enhanced to 192 mm to accommodate bolts.
The question is for design of thickness of Channel barrel is it required to use formula at Appendix 1-2(a)(1) based on provided thickness or it would suffice to use formula at UG-27 based on required thickness.

Here required thickness (37 mm) is less than 0.5 X radius ie. 0.5 X (0.5 x 563) = 140.5 mm, where as provided thickness (192 mm ) is greater than 140.5 mm.

Per UG-27 limitation, Design pressure P (159 barg = 162.13 Kg/cm^2 g) is not greater than 0.385 SE = 0.385 X 1406 = 541 Kg/cm^2.

See attached sketch of HP Channel End.

 

[SnTMan]

DK44, if my arithmetic has not failed me I am getting about 3 mm difference (thinner) with the Appendix. I'd say it hardly matters, but to meet the dimensional limit of UG-27, I'd go with the Appendix.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[DK44]

Thank you SnTman.
Leaving aside the small thickness difference, my question is whether the usage of Appendix is based on provided thick or required thickness.

 

[SnTMan]

Well, kind of a grey area, but for finding required thickness I think you'd be justified in using UG-27 since that thickness does not meet the limitations. Now if you want to find MAWP from your selected thickness, I'd say use the Appendix.

Regards,

Mike

Edit: Strikeout the word.

 

[DK44]

Thank you SnTman.
When we can use UG 27 for thickness calculation, I suppose, we can use it for back calculating the pressure (MAWP) with provided thickness. Why to use two different formulas, one for thickness and another for MAWP.

 

[SnTMan]

Well, because the first one (UG-27 thickness) meets the thickness vs radius limitation, while the second (UG-27 MAWP) does not.

But, it is kind of splitting hairs, especially if the cylinder is not the limiting MAWP.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[DK44]

Thank you SnTman.

The discussion tends to following corollary for such cases.

In actual situation, when we know ID only, we use UG-27 to find out required thickness. After knowing the thickness and enhancing it to higher thickness for Bolted End connection purpose, which exceeds the limitation of UG-27, we recalculate the required thickness with Appendix 1-2(a)(1) and so calculate MAWP for the provided thickness.

Am I right.

 

[SnTMan]

Yeah, I'd say sounds about right.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

The required thickness of UG-27 and App 1-2(a)(1) is the same in your example.
No limit is in UG-27
The equations in App 1-2(a)(1) may be used in lieu of those given in UG-27(c)

DK44, Please read again the following:
MANDATORY APPENDIX 1
SUPPLEMENTARY DESIGN FORMULAS

(17) 1-2 CYLINDRICAL SHELLS
(a) Circumferential Stress (Longitudinal Joints). When
the thickness (REQUIRED) of the cylindrical shell under internal design
pressure exceeds one‐half of the inside radius, or when P
exceeds 0.385SE, the following equations shall apply. The
following equations may be used in lieu of those given in
UG-27(c)

I added (REQUIRED)

Regards
r6155

 

[DK44]

Dear r6155.
Neither the required thickness (37 mm) nor the pressure (162.13 Kg/Cm^2) exceed the limitations of UG-27 in the example.

 

[MohdYaseen2010]

I am agree with (r6155); but let me concluded in simple way;

Use UG-27(c)(1) Formulas for → Cylindrical Shell - Circumferential Stress (Longitudinal Joints) if → THK ≤ IR/2 or P ≤ 0.385SE
Use UG-27(c)(2) Formulas for → Cylindrical Shell - Longitudinal Stress (Circumferential Joints) if → THK ≤ IR/2 or P ≤ 1.25SE
Use UG-27(d) Formulas for → Spherical Shell if → THK ≤ 0.356R or P≤ 0.665SE

1-1 provide same formulas as UG-27(c)&(d) but using OR instead of IR.
Use 1-2(a)(1) Formulas for → Cylindrical Shell - Circumferential Stress (Longitudinal Joints) if → THK > IR/2 or when P > 0.385SE
Use 1-2(a)(2) Formulas for → Cylindrical Shell - Longitudinal Stress (Circumferential Joints) if → THK > IR/2 or when P > 1.25SE
Use 1-3 Formulas for → Spherical Shells if → THK > 0.356R or P> 0.665SE


Mohd Yaseen

 

[DK44]

Dear r6155 and MohdYaseen2010. Thank you very much.
There is no dispute on these provisions.
The question is whether alternate rules of APPENDIX 1-2(a)(1) are applicable based on required thickness (37 mm in this case) or provided thickness (192 mm in this case).
Somehow this basic question does not appear to be addressed since the start of this discussion. I do not have much further to explain this basic query. It remains same.

 

[r6155]

OK DK44
Always I use only equations in App 1-1, not UG-27.

Regards
r6155

 

[DK44]

r6155. Thank you.
If ID is only known and OD is to be fixed (as in the case of Heat Exchanger and Pressure Vessel Shells, we have to use ID formula only I suppose.

 

[r6155]

Ohhhh sorry my mistake

Instead of "Always I use only equations in App 1-1, not UG-27." please read
"Always I use only equations in App 1-2, not UG-27".

My apologies to all my colleagues !!

Regards
r6155