jimmyhutmacher
Mechanical
- Jan 11, 2011
- 50
Can't seem to sort this discrepancy out, could use some advice:
Equation (15) of API 2000, for the required flow capacity, states that "T" the absolute temperature of the relieving vapor is normally assumed to be the bubble point of the stored fluid. However, the "cookbook" tables 5, 6, 7 and 8 for hexane, which are derived from the same equation, assumes "T" is 60F (519.67R) instead of the bubble/boiling point of hexane 156.2F (615.87F). Any thoughts on the reasoning for this discrepancy?
Using ambient temperature vs. bubble point doesn't make a substantial difference for the hexane tables (~9% difference for Wetted Area > 2800 sq ft), but it's a surprising choice since it makes the tables less conservative and also, it makes quite a difference when you get into higher boiling point liquids.
Thanks for your help!
Equation (15) of API 2000, for the required flow capacity, states that "T" the absolute temperature of the relieving vapor is normally assumed to be the bubble point of the stored fluid. However, the "cookbook" tables 5, 6, 7 and 8 for hexane, which are derived from the same equation, assumes "T" is 60F (519.67R) instead of the bubble/boiling point of hexane 156.2F (615.87F). Any thoughts on the reasoning for this discrepancy?
Using ambient temperature vs. bubble point doesn't make a substantial difference for the hexane tables (~9% difference for Wetted Area > 2800 sq ft), but it's a surprising choice since it makes the tables less conservative and also, it makes quite a difference when you get into higher boiling point liquids.
Thanks for your help!
