ITK-234 Termodinamika Teknik Kimia II VLE Calculations for Nonideal Mixtures Dicky Dermawan www.dickydermawan.net78.net dickydermawan@gmail.com Modified Raoult’s Law K-value Method VLE using Equation of States Dicky Dermawan Incorporation of fugacity and activity coefficient to vle criteria results: y k k P x k k Pk sat Vk P Pk where k exp R T ˆ k sat However, at low pressure (up to at least 1 bar): ˆ k sat ˆ ˆ k k 1 The Poynting Factor 1 Modified Raoult’s Law: y k P x k k Pk sat sat Modified Raoult’s Law: Wilson Equation for calculating a. b. Prepare a P-x-y diagram at 80oC 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. b. Prepare a P-x-y diagram at 80oC 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. b. Prepare a P-x-y diagram at 80oC 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) from 12.6 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 yk k P x k k Pk sat sat V P P k k exp k R T ˆ k sat ˆ k y k k Pk sat Kk f ( T, P ) xk k P yi K i x i The nomographs K = f(T,P) prepared by De Priester provide easy application of this approach to practical problem K-Value Method: Using De Priester Charts for light hidrocarbons High Temperature Range K-Value Method: Using De Priester Charts for light hidrocarbons Low Temperature Range Type of Phase Equilibria Calculations BUBL P calculation: Given T & liquid composition xi, Find the bubble point Pb & vapor composition Assume P, find Ki satisfying: DEW P calculation: Given T & vapor composition yi, Find the bubble point Pb & vapor composition Ki x i 0 Assume P, find Ki satisfying: yi 0 Ki Type of Phase Equilibria Calculations BUBL t calculation: Given P & liquid composition xi, Find the bubble point Pb & vapor composition Assume t, find Ki satisfying: DEW t calculation: Given P & vapor composition yi, Find the bubble point Pb & vapor composition Ki x i 0 Assume t, find Ki satisfying: yi 0 Ki 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 Make sure P located between Pb dan Pd, i.e. Perform BUBL P for zi =xi and Perform DEW P for zi = yi Find Ki ; assume V satisfying: zi xi 1 1 K i 1 V or: yi or: The General Solution Procedure zi K i 1 1 K i 1 V z i (K i 1) 0 1 K i 1 V 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