AUXILIARY FACILITIES of Distillation Column.pptx

AUXILIARY FACILITIES of Distillation Column

1. AUXILIARY FACILITIES of Distillation Column

2. Figure 3 is a more detailed process flow diagram of the Ras Tanura Plant 10 Depropanizer . It provides more information on auxiliary facilities such as pumps, piping, valves, instruments, and controls. A typical distillation tower has pumps for feed, reflux/distillate, and, if required, bottoms. In the depropanizer , bottoms pumps are not required because the downstream unit, the debutanizer, is at a lower pressure. Control valves are used to maintain stable rates (e.g., feed and reflux rates) and stable liquid levels in the distillate and bottoms surge vessels. Instruments such as flow meters and pressure, temperature, and level indicators are used to monitor and control the operation of the tower. Instruments such as gas chromatography analyzers are used to monitor the quality of separation by identifying the concentration of important components. In the depropanizer , for example, an analyzer in the liquid distillate identifies the concentrations of ethane, isobutane, and n-butane. These are components related to the propane product specifications. Various control schemes are used to achieve objectives such as stable feed rate, on-spec products, low utility consumption, and stable operation. The Ras Tanura Plant 10 Depropanizer , for example uses the following three control schemes:

3. Feed temperature control to assure stable feed vaporization levels. • Reboiler steam rate control, related indirectly to the concentration of propane in the bottoms via a tray temperature. • Tower pressure control which is necessary for the stable operation of the tower