RCE engineers visited a new client’s plant that was originally built as a Residue Recycle (RR) process around 30 years ago. At some point the inlet gas rates increased and it was modified to be a Gas Sub-Cooled (GSP) process with the reflux split occurring on the inlet gas. This made great sense at the time as it allowed the plant to process about 20% more inlet gas with only a modest decrease in ethane recovery. This occurred about 10-15 years ago. Through plant acquisitions and personnel turnover, the understanding that there was a RR mode and how to switch modes was lost. During the plant visit RCE engineers noticed the connections still in place to run RR. The inlet gas rates had dropped back to below the original RR design rates, and the recoveries in GSP mode were low. Taking RCE’s recommendation, the 4″ valve on the residue line was opened and the 4″ valve on the inlet line closed. Recoveries immediately improved, and the plant sustained a 200+ BPD (~10%) increase in EPBC, a gain of over 3 $MM/year. Another example of how RCE is doing our part to help improve our client’s bottom line.