During the experiment described in Problem 2.3, the air velocity was measured at \(6 \mathrm{~m} / \mathrm{s}\), parallel to the longest side of the pan. Estimate the mass-transfer coefficient predicted by equation (2-56) or (2-57) and compare it to the value measured experimentally. Notice that, due to the high volatility of acetone, the average acetone concentration in the gas film is relatively high. Therefore, properties such as density and viscosity should be estimated carefully. The following data for acetone might be needed: \(T_{c}=508.1 \mathrm{~K}, P_{c}=47.0 \mathrm{bar}, M=58, V_{c}=209 \mathrm{~cm}^{3} / \mathrm{mol}\), \(Z_{c}=0.232\) (Reid et al., 1987).

Data From Problem 2.3:-

In a laboratory experiment, air at \(300 \mathrm{~K}\) and 1 atm is blown at high speed parallel to the surface of a rectangular shallow pan that contains liquid acetone \(\left(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}\right)\), which evaporates partially. The pan is \(1 \mathrm{~m}\) long and \(50 \mathrm{~cm}\) wide. It is connected to a reservoir containing liquid acetone which automatically replaces the acetone evaporated, maintaining a constant liquid level in the pan. During an experimental run, it was observed that \(2.0 \mathrm{~L}\) of acetone evaporated in \(5 \mathrm{~min}\). Estimate the mass-transfer coefficient. The density of liquid acetone at \(300 \mathrm{~K}\) is \(0.79 \mathrm{~g} / \mathrm{cm}^{3}\); its vapor pressure is \(27 \mathrm{kPa}\) (Perry and Chilton, 1973).

Data From Equation 2-56 and 2-57:-

Transcribed Image Text:

0.5 c 1/3 (laminar) R <3105 (2-56) Sh =0.664 Re Sc 1/3 (laminar) 0.8 Sh=0.036 Re Sc1/3 (turbulent) R, 3105 (2-57)