aspen sumilation

[ahmed2012]

plz help me for this Aspen problem's :

It is proposed to separate by distillation a liquid mixture composed of 40 mol%. n-pentane (denoted briefly ₅ C) and 60% n-hexane (C ₆). Food - a flow F = 1000kmol / h - is the state of saturated liquid under the pressure of 2.8bar. The separation is performed in a rectification column with N theoretical stages (including reboiler and condenser, respectively stages 1 and N).

By proceeding in a first operation under the following operating conditions:

Bit rate of distillate, D = 400kmol / h,

· Rates of reflux RR = (R / D) = 5, with R, reflux flow,

· Pressure Column: 2.7-2.9 bars,

we get a quality product of head and foot of the column enough xD = 89% and (1-xB) = 93%: for technical products, the purity must be at least 95% for both hydrocarbons.

In order to obtain products that comply with these specifications, it was thought to increase the reflux ratio and change the power stage by keeping fixed the rest of the operating parameters. Find the conditions for achieving the purities xD = 95% (1-xB) = 96.5%.

[aseptman]

with about 30 the stages incl reb and cond
Feed at 15 th stage
column top pressure 2.8 bar(a)
with peng-Robinson or srk
if specs are
Dist 400 kgmol/hr and RR=5
you get both comps above 99%