(17e) C2 Splitter Pressure Control Problems and Solutions

Twinning of a parallel C2 Splitter overhead condenser was implemented as part of an expansion project. The project scope also included a full re-tray of the tower, provision for a new side reboiler and twinning of the bottom reboiler. Pressure control difficulties were encountered during commissioning of the tower and required changing the operating strategy of the 2 C2 Splitter system. Excessive overhead condenser heat transfer area, exchanger design and piping configuration are believed responsible for the difficulties in controlling the tower pressure. Condensation of the tower overhead vapor is done by core and kettle heat exchangers, which uses propylene refrigerant on the kettle side. Pressure control of the tower is normally done by varying the propylene refrigerant level on the kettle side of the exchanger. This paper discussed the impact of exchanger design, available heat transfer surface and piping configuration relative to stable tower pressure control.