Hello,
I'm the project engineer of a fuel (gasoline and diesel) transloading system, to which relief valves should be included in the design. The valves will be located on a 6" pipe, which collects fuel from tank cars (cars at atmospheric pressure). The fuel is pumped to tank trucks, and the released vapor is sent back to the tank cars.
I'm kindly asking for your recommendations, by choosing a TRV or a PSV valve.
I already performed the TRV calculation, by setting pressure at 18 psi_g, according to process conditions. Set pressure was calculated by fluid hydrostatic pressure plus vapor pressure at normal boiling point. Volumetric relief flow was calculated from API 521 Addendum.
On the other hand, if PSV is chosen, its design must be carried out to address fire case (liquid vaporization). However, API 521 correlations are intended to vessels rather than pipes; in particular, because wetted area is needed. Could I use the correlations anyway?
Finally, either for TRV or PSV, I have some doubts on choosing set pressure. Is API 576 applicable to determine set pressure?
I'm aware that I posed several technical issues. I would really appreciate your help.
Regards.