itk-234 termodinamika teknik kimia ii

ITK-234 Termodinamika Teknik Kimia II

Dicky Dermawanwww.dickydermawan.net78.net

dickydermawan@gmail.com

VLE Calculations for Nonideal Mixtures

Modified Raoult’s Law K-value MethodVLE using Equation of States

Dicky Dermawan

satkkkkk PxPy

TR

PPVexp

ˆ

ˆ satkk

satk

kk

1ˆˆ satkk

Incorporation of fugacity and activity coefficient to vle criteria results:

Modified Raoult’s Law:

where

However, at low pressure (up to at least 1 bar):

The Poynting Factor 1

satkkkk PxPy

Modified Raoult’s Law:Wilson Equation for calculating

a. Prepare a P-x-y diagram at 80oC

b. Prepare a t-x-y diagram at 101,33 kPa

Modified Raoult’s Law:Wilson Equation for calculating (Cont’)

Use your diagram to answer there questions:

Given P = 70 kPa, T = 80oC & overall composition, z1=30%

Find the fraction of system which is liquid (L) & vapor (V) and their respective compositions xi & yi

Modified Raoult’s Law:Wilson Equation for calculating

a. Prepare a P-x-y diagram at 80oC

b. Prepare a t-x-y diagram at 101,33 kPa

Modified Raoult’s Law:Wilson Equation for calculating (Cont’)

Use your diagram to answer there questions:

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:Wilson Equation for calculating

Modified Raoult’s Law:NRTL Equation for calculating

a. Prepare a P-x-y diagram at 80oC

b. Prepare a t-x-y diagram at 101,33 kPa

Modified Raoult’s Law:NRTL Equation for calculating

VLE Calculation Using No Diagram

Answer the questions (a) through (e) from12.6 to 12.13 but don’t use the phase diagram to obtain the answers

Estimating Azeotrophic Condition,Use No Diagram

K-Value Method:Using De Priester Charts for light hidrocarbons

satkkkkk PxPy )P,T(f

P

P

x

yK

k

satkk

k

kk

iii xKy

The nomographs K = f(T,P) prepared by De Priester provide easy application of this approach to practical problem

TR

PPVexp

ˆ

ˆ satkk

satk

kk

K-Value Method:

Using De Priester Charts for light hidrocarbons

HighTemperatureRange

K-Value Method:

Using De Priester Charts for light hidrocarbons

LowTemperatureRange

Type of Phase Equilibria CalculationsBUBL P calculation:

Given T & liquid composition xi,Find the bubble point Pb & vapor composition

DEW P calculation:Given T & vapor composition yi,Find the bubble point Pb & vapor composition

0xK ii

Assume P, find Ki satisfying:

0K

y

i

i

Assume P, find Ki satisfying:

Type of Phase Equilibria Calculations

BUBL t calculation:Given P & liquid composition xi,Find the bubble point Pb & vapor composition

DEW t calculation:Given P & vapor composition yi,Find the bubble point Pb & vapor composition

0xK ii

Assume t, find Ki satisfying:

0K

y

i

i

Assume t, find Ki satisfying:

K-Value Method:Using De Priester Charts for light hidrocarbons

K-Value Method:Using De Priester Charts for light hidrocarbons

Type of Phase Equilibria Calculations

FLASH calculation:Given P, T & overall composition,Find the fraction of system which is liquid (L) & vapor (V) and their respective compositions xi & yi

1V1K1

zx

i

ii

Make sure P located between Pb dan Pd, i.e.Perform BUBL P for zi =xi andPerform DEW P for zi = yi

Find Ki ; assume V satisfying:or:

or: The General Solution Procedure

1

V1K1

Kzy

i

iii

0

V1K1

)1K(z

i

ii

K-Value Method:Using De Priester Charts for light hidrocarbons

K-Value Method:Using De Priester Charts for light hidrocarbons

K-Value Method:Using De Priester Charts for light hidrocarbons