During a walkthrough on a job we recently completed (at an idustrial site), the local official requested that an overhead 6" natural gas pipe be labeled every five feet stating that the line was NG and the operating pressure.
That seemed a little excessive to us, especially the operating...
Another resource may be Energy Products of Idaho. They have a decent library of their papers on the subject, but they may be more focused on the BFB gasifier add-on approach to using biomass with coal.
I'm not familiar with the books mentioned by other replys, but our office recently purchased "Heat Exchanger Design Handbook" by Kuppan published by CRC Press. It seems to be very thorough on design theory as well as applications. It helped me to understand the theory behind the long...
Some second thoughts here. The reason the calculated T1 is so high is because relieving pressure,P1, is large compared to normal operating pressure,Pn. P1 gets so big because allowable overpressure is based on MAWP, not set pressure. This is a case where my set pressure is way below MAWP...
Thanks Mike for the response. I understood that the T1 was greater than Tw making the non-real result, but I wasn't connecting the dots that the internal pressure rise due to the heat input would not reach relieving pressure before the vessel would probably rupture. I'll do some more reading...
API 521 Section A.5.2.1 gives an equation for discharge area. For the F' term, "The recommended minimum value of F' is 0.01; when the minimum value is unknown, F'=0.45." What does that mean? I can calculate F' from the given equation, however I get a non-real result because T1 is greater than...
Thanks for the comment skearse. To answer your questions...The set is lower than MAWP to minimize spares. The capacity required is comparable to a similar vessel with a lower MAWP. It is "pop" valve.
From my reading of API 520 for fire contingency, it seems that regardless of relief valve set pressure, the value for P1 (relieving pressure) used in the calculations is MAWP + allowable overpressure + 14.7 psia. I'm using Table 5 as the example here. MAWP is 100 psig, set is 90 psig...
Thanks everyone for your valued input. We will go through the proper analysis and if the capacities allow, we will use identical relief valves.
Cheers!
MechBRR
JoeWong, thanks for your reply. I can clarify a little bit here. The vessel mentioned is a liquid vessel whose relief valve was sized based on wetted surface area. The two heat exchangers needing overpressure protection are not the same. One is a condenser upstream of the stated vessel. It...
I'm sizing PSV's for fire case on two heat exchangers located near an upstream vessel for which a PSV exists (isolation valves are installed in connected piping). By inspection the surface area of the heat exchangers is about two thirds of the vessel for which the PSV exists. I've been asked...
Thanks, Jackal, for the quick reply. The ID of the shell is over 6", but I will need to check distance between the outer tube and the shell. Does the fact that the tube bank occupies the internal space of the shell allow another dimension other than the ID of the shell to be considered under...
While reviewing existing equipment we came across a type of heat exchanger in use that may or may not fall under Section VIII Div 1. It is a single pass carbon tube cartride with a water cooled steel shell. The process (tube) side carries product at 1/2 to 2 psig and the shell side carries...
