I am trying trouble shoot an issue with a C5 splitter. Specifically, high temperature of the liquid leaving the reflux drum.
The attached drawing shows the installed control scheme.
1. The site previously used a liquid full reflux drum controlling column pressure by varying the distillate rate. The overhead system was converted to the schematic shown in the drawing by adding the pressure control valve between the condenser and the reflux drum and adding the equalization line.
2. The condenser is a total condenser and subcools the overhead vapor to ~10F above ambient temperature.
3. The reflux drum is getting quite hot. The liquid product leaving is close 130F. My understanding is that this temperature should exceed the condenser outlet temperature by no more than 2-3F.
4. There is a lot of "banging" occuring in the reflux drum. I assume this to be shock condensation.
5. The overhead line is 6". The equalization line is 2". The equalization line itself is only about 10ft long and ties into the vapor space on the drum. The equalization line take off from the overhead line is approximately 1/3 of the way down the line running to the condenser.
6. I don't have drawings of the reflux drum internals. I have seen pictures taken by inspectors and it appears the feed pipe has a down leg that
goes to the bottom of the drum (i.e., I don't believe there is subcooled liquid contacting the vapor space).
7. The boiling range of the overhead product is pretty tight (around 1F).
Any thoughts / ideas?