VLE/batch distillation

y = -0.0021x2 + 0.0342x + 0.4969

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Experimental Sharpness Curve

Sharpness Curve Poly. (Sharpness Curve)

Christopher S. Mukiibi, Bryan Le, Mohammed Al Alawi, Turki Al Habsi California State University, Long Beach

Chemical Engineering Department

Introduction: Azeotrope is a special class of liquid mixture that boils at a constant

temperature at a certain composition. a binary mixture of 1-propanol-water

was used in this experiment to evaluate the validity of our analytical

prediction when using batch distillation. Azeotropic batch distillation is

applied in such applications such as wastewater treatment, and in separation

process of pharmaceutical industry.

Conclusion and Error Sources: Batch distillation process allows better product integrity. Each batch of the product can

be clearly identified in terms of feeds involved and conditions of processing. This is

particularly important in the food and pharmaceutical industries.

Errors possibly resulted from contamination of the solution or reuse.

Theory & Results: The Antoine Equation is as follows:

With the azeotropic temperature of 87.7°F, the Antoine equation is used to calculate saturated pressure for 1-propanol and water. In this experiment Psat1 is the saturated pressure of 1-propanol and Psat2 is the saturated pressure of 2- propanol. Azeotropic point is when X (liquid mol fraction) and Y (gas mol fraction) are equal.

Raoult’s Law is as follows:

With the saturated pressures and azeotropic temperature, Raoult’s Law is used to calculate the activity coefficient (!) by assuming X=Y. The table below depicts parameters for the three models.

Procedure: • Set up the batch distillation and turn on the reflux.

• Weigh about 100 ml of 1-propanol-water mixture at 10%, 15%, and 20% 1-propanol to water

ratio.

• Pour the weighed mixture into the boiling flask.

• Distillate will pour into beaker on electronic balance

• Zero balance with

• Zero the refractometer with DI water.

• Measure refractive index of initial mixture to obtain the initial mass fraction of 1-propanol.

• Begin heating the mixture.

• Measure the refractive index and mass of the condensing liquid every 1-degree Celsius it

increases.

• Continue collecting data until the weight percent of 1-propanol in the distillate vapor runs out.

Materials: • Othmer Still Distillation Apparatus

• Boiling Flask

• Heating Mantle

• Condenser

• Vials/Beakers

• Refractometer

• Electronic Balance

• Boiling Chips

Experimental Apparatus

Acknowledgements: Dr. Roger C. Lo

Dr. Larry Jang

Objective: The objective of this experiment is to analyze and study the azeotropic

equilibrium conditions such as VLE composition, Dew Point, and Bubble Point.

The graph to the right depicts the Bubble Point (BP) and Dew Point

(DP) prediction using the Van Laar Model.

The graph above is the experimental sharpness curve.

The graph to the left depicts a Vapour-Liquid Equilibrium (VLE) composition prediction based off the Van Laar Model.

Image to the right displays the actual distillation set up for the

experiment.

The figure to the left displays a diagram of the distillation set up for the experiment. The Condensate receiver would sit on an electric balance to measure mass.

Predicting Azeotropic Batch Distillation Equilibrium Conditions

Image to the left displays the refractometer. The

cover over the lens must be closed when performing

readings.

References: McCabe, Smith, Harriott. Unit Operations of Chemical Engineering, 6th edition. McGraw- Hill. 2001. Print. Jang, Larry K., Prediction of Vapor-Liquid Equilibrium for a Non-Ideal Binary Mixture Based on the Azeotropic Condition. SciMed Central. 2017. Print.

The graph below depicts the experimental results of model

parameters