VLE/batch distillation
Prediction of Vapor Liquid Equilibrium of Non-ideal Binary Mixture Using Van Laar Model.
Aron Avella-Valencia, Hiep Nguyen, Marisol Bernal
Department of Chemical Engineering, CSULB
Dr. Jang
ChE 450
09/25/19
Introduction
How is the application of VLE important in industry?
Distillation
Environmental modeling
General process design
What factors need to be considered before predicting VLE?
Parameters of Antonie Equation for compounds used.
Chose system known to have azeotrope.
Non-ideal solution but still one phase.
Objectives
Predict VLE of non-ideal binary mixture using water and 2-propanol at atmospheric pressure.
Model results using Van Laar.
Compare model with PRO II.
Find relation between batch distillation and VLE.
Experimental Apparatus
Refractometer
Othmer still
70% Isopropyl Alcohol
Procedure
Turn on power supply and set at 50.
Set up the refractometer.
Perform 2 Point Calibration
Use pure water and 2-propanol.
Once mixture is boiling, add 2-propanol or water.
Wait about 20 minutes.
Take sample of condensed vapor and liquid.
Record refractive index and temperature.
Repeat every 2 minutes until equilibrium is reached.
Safety Concerns
Potential Hazards
Do not drink the binary mixture.
Wear goggles & lab coat.
Mixture can flash out.
Do not spill on electrical equipment.
Isopropanol is highly flammable and causes eye irritation.
GHS-US labeling
NFPA
Equation, Theory, Data Analysis
Refractive Index to Wt % Isopropanol
Assume 100g basis to find mol fraction of isopropanol
Equation, Theory, Data Analysis
Antoine Equation:
Parameters of Antoine equation for 2-propanol and water.
Equation, Theory, Data Analysis
Van Laars derived azeotrope temperature of 80.37 Celsius and composition values close to published values
Results
Discussion/Summary
Our experimental data follows the trend reasonably well.
We measured the refractive index for our second run before it reached equilibrium.
To properly distill using batch distillation, you have to know VLE.
Recommendations
Make sure you wear goggles as hot liquid can flash out of condenser.
Ensure that refractive index readings are within range.
Do not spill as it may cause an electrical hazard.
If time permits, calculate & compare bubble point & dewpoint with PRO II model.