Reference no: EM133128181

CHME322 Chemical Engineering Thermodynamics - United Arab Emirates University

Question 1: Nitrobenzene is made by the direct nitration of benzene by nitric acid in the presence of strong sulphuric acid solution:

C₆H₆ + HNO₃ → C₆H₅NO₂ + H₂O

The actual nitrating agent is the nitronium ion, NO₂⁺, and the sulphuric acid is needed to generate this from the nitric acid feed.

Reconcentrated sulphuric acid, of strength 74% by weight and X°C is mixed with pure nitric acid at 25°C to give a nitric acid strength in the mixture of 7.5% by weight. The heat of mixing causes a temperature rise to 95°C. The mixed acid is then passed through a heat exchanger to bring its final temperature to 65°C and fed to the reactor. Liquid benzene at 25°C is also fed to the reactor at a rate to give a 10% stoichiometric excess based on the nitric acid flow.

The reactor operates adiabatically and gives 100% conversion of the nitric acid. All products leave the reactor as liquids at Y°C. The sulphuric acid is re-concentrated to 74% and recycled, while the nitrobenzene is sent for purification.

Using the attached thermodynamic data, you are asked to calculate:

(i) the temperature, X°C of the reconcentrated sulphuric acid
(ii) the amount of water removed to bring the concentration of the sulphuric acid solution back to 74%
(iii) the temperature, Y°C, at the exit of the reactor
(iv) the heat load on the heat exchanger per kg of nitrobenzene produced.
(v) Discussions of the overall results and what you have learnt.

You may assume that the organics benzene and nitrobenzene form an ideal liquid mixture, and there is complete immiscibility between organics and inorganics.

Question 2: For a binary mixture of Acetone and Hexane

(i) If the mixture forms an azeotrope boiling at 49.6 °C at 1 atm pressure, with a composition x₁ = 0.625. Calculate the van Laar and the Margulus Coefficients for the system and compare them to the values published in literature.

(ii) Using the van Laar and the Margulus Coefficients found in literature, determine the dew point and the bubble point for ten different compositions

(iii) Use the data developed in part 2 to determine the van Laar and the Margulus Coefficients. Comment on your results.

(iv) Using the van Laar and the Margulus Coefficients found in literature, determine the equilibrium pressures of ten different liquid compositions.

(v) Use the data developed in part 4 to determine the van Laar and the Margulus Coefficients. Comment on your results.

(vi) Discussions of the overall results and what you have learnt.

Attachment:- Chemical Engineering Thermodynamics.rar