Page 148 - Process simulation and control using Aspen

136 PROCESS SIMULATION AND CONTROL USING ASPEN '
3 ASPEN PLUS SIMULATION OF THE MULTICOMPONENT
3 .
DISTILLATION COLUMNS

3 . 3 . 1 Simulation of a RadFrac Model

Problem statement
A multicomponent distillation column, specified in Figure 3.38, has total 20 stages
(including condenser and reboiler) with 60% Murphree efficiency. A hydrocarbon feed
mixture enters above tray 10 of the RadFrac column. Apply the Peng-Robinson
correlation and consider 120 psia pressure throughout the column.
(a) Simulate the model and calculate the product compositions, and
(b) Produce a Temperature' (0F) vs. 'Stage' plot.

Feed Specifications < Vapour Distillate Specifications
Flow rate = 100 Ibmol/hr
Flow rate = 50 Ibmol/hr
Temperature = 120F Reflux rate = 125 Ibmol/hr
Pressure = 120 psia
Component Mole%
C3 5
/-C 15
4
n-C 20
4
' C5 25
-
A?-C5 35
FIGURE 3.38 A flowsheet of a distillation column
.
Simulation approach
(a) As we start Aspen Plus from the Start menu or b y double-clicking the Aspen
Plus icon on our desktop , the Aspen Plus Startup dialog appears (see Figure 3.39).
Select Template option .

FIGURE 3.39