Exercise 02 ENG

Pagina 1

Page 1 of 2 Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta” POLITECNICO di MILANO Practical class (informatic laboratory) of Chemical Processes and Technologies (Prof. Stefania Moioli) 1. Vapour pressure estimation Ethyl acetate has a vapour pressure of 118.3 mmHg at 29.5 °C, and a normal boiling point of 77.0 °C. a) Determine the parameters of the Clausius-Clapeyron type equation so that it is possible to calculate its vapour pressure in: mmHg, atm, bar, psi. b) Estimate its vapour pressure at 45 °C using: - the Clausius-Clapeyron type equation with the parameters previously determined; - the Antoine equation: 2790.50ln( [ ]) 16.1516 [ ] 57.15 evP mmHg TK=− − ; - a linear interpolation between the two values given for its vapour pressure. Discuss, then, the obtained results. 2. Bubble- and dew-point calculations Vapour-Liquid Equilibrium (VLE) conditions of a n-pentane/i-pentane mixture can be rep resented by the Raoult’s Law: , ()i ev i iP y P T x =  . a) Compute the bubble-point pressure and the dew -point pressure for an equimolar mixture of the two hydrocarbons at 120 °C. b) For the same mixture, compute the bubble -point temperature and the dew -point temperature at 1200 mmHg. c) Draw the P-x-y diagram at 120 °C and the T-x-y diagram at 1200 mmHg for the binary system n-pentane/i-pentane. For cases a) and b), also compute the composition of the liquid and of the vapour phases. Data The vapour pressure is calculated with the Antoine equation: ln( [ ]) [] ev BP mmHg A T K C=− + Component A B C i-pentane 15.6338 2348.67 -40.05 n-pentane 15.8333 2477.07 -39.94 2 3. Calculation of fugacity coefficients using the Peng-Robinson Equation of State (PR EoS) Considering an equimolar mixture of n-butane and n-octane, calculate the fugacity…