All,
I have a general question about tube ruptures for reboilers on distillation columns. I was able to calculate the tube rupture rate based on accepted methods. For the sake of this inquiry, let's say it resulted in 10,000 lb/hr.
Next, I looked at the boiling point of the column contents at relieving conditions. This boiling point was higher than the steam temperature at relieving conditions, so I assumed that nothing more would vaporize due to the tube rupture.
However, if I mix the tube rupture stream and the feed to the column together to a flash block in Aspen at steady state, I get a vapor rate that is double the original tube rupture rate at ~20,000 lb/hr. The normal feed to the column is heavier organics, and the water is driving down the boiling point.
Is it overly conservative to assume that there will be a fraction of water in the column at equilibrium with the column feed during the relieving event? Or will the steam displace vapor out of the relief valve without intimate mixing of the column contents?