Exercise 11 Text Kinetics

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Department of Energy Politecnico di Milano Via Lambruschini 4 - 20156 MILANO Exercises of “Fundamentals of Chemical Processes” Prof. Gianpiero Groppi EXERCISE 11 Reactor for the esterification of butanol The following data were obtained in a homogenous ba tch reactor for the esterification of butanol (B) with acetic acid (A): CH 3COOH + CH3CH2CH2CH2OH  CH3COOCH2CH2CH3 + H2O The experiments were carried out at a 100°C, starting from the following initial conditions: A 0 = 0.2332 mol B 0 = 1.1600 mol The data collected during the experiments are reported in the table below. The batch volume is equal to 120 cm3. Determine the parameters of the power law type kinetic equation that describes the experimental results. Furthermore, assume that the reaction is also carried out in a flow-type reactor. Specifically, compare the results obtained in the case of a CSTR reactor and a PFR reactor. At the inlet of the reactor, the flow rate of acetic acid is 1 mol/h (MM = 60 g/mol, density = 1050 kg/m 3) and that of butanol is 5 mol/h (MM = 74 g/mol, density = 810 kg/m3). Assuming that the mixture is ideal and that the total volumetric flow rate (acetic acid and butanol) maintains constant, estima te the volume required by each reactor in case the target conversion of acetic acid is 32%. Data t [h] Converted moles of A 0 0 1 0.01636 2 0.02732 3 0.03662 4 0.04525 5 0.05405 6 0.06086 7 0.06833 8 0.07398 2 Solution The reaction rate (r) is expressed by a power law type expression:  BA CCkr  Given that the consumption stoichiometry is equimola r, at the end of the reaction 0.07398 mol of butanol are converted. Therefore, the amount of butanol maintains almost constant, passing from to 1.16 mol at the beginning, to 1.086 mol at the end of the reaction. The concentration of butanol C…