The main equipment of cracked gas compressor unit includes five stage compressors whose numbers are K-13001, K-13002, K-13003, K-13004, and K-13005; alkali washing tower whose number is C-1340; and high pressure depropanizer
tower whose number is C-1365.
To test the methodology proposed in previous section, a depropanizer
process (Lee, 1993) is used as a case study where the mole fractions of propane in distillate and isobutane in bottom product are controlled by simultaneously adjusting the reflux ratio (RR) and boil-up rate (Q) in the face of sinusoidal disturbances in feed composition.
The effect of neglecting the vapour phase in the simulation of a depropanizer
operating at a pressure of 15 bar is illustrated in Figure 7 where the propane composition in the bottoms is plotted as function of the time after an increase in the reflux ratio.
The new plant is operating at its capacity of 30 million cubic feet per day (MMcf/d) and includes a depropanizer
to extract propane from the gas stream that is sold into the regional market.
In addition, MarkWest is constructing a 30 MMcf/d cryogenic processing plant, which includes a depropanizer
to extract propane from the gas stream, which is expected to commence operations in the first quarter of 2009.
The cryogenic plant is being constructed next to the refrigeration plant and includes a depropanizer
to extract propane from the gas stream, which will be sold regionally.