We have several shell & tube kettle-type heat exchangers where propylene refrigerant is in the shell, process in the tubes. The propylene is flashed to either 70 psig (35 degF) or 6 psig (-40 degF), depending on the exchanger. The level indication/control of the refrigerant is all over the place, so they all run in manual. The exchangers are old, and what we have is dP level indication in an uninsulated stilling well. Thinking that the propylene was flashing in the exposed well, we recently insulated a well and replaced dP with guided wave Radar. It's better, but still not under control and still spikes up & down a lot. In all cases the propylene is dry (no hydrates forming), but we do have to drain a bit of compressor lube oil from the shells ever week or so. So, I wonder if anyone has any suggestions for refrigerant level control.

Thanks, Dean

 

Are you after continuous or point level control?

Thanks
[email protected]

 

Bob,

I'm looking for continuous level control. I'd like to control the process-side discharge temperature of one of the exchangers and was thinking of a cascade loop where temp control resets the refrigerant level.

Thanks,
Dean