Benzene is evaporating at \(20 \mathrm{~kg} / \mathrm{h}\) over the surface of a porous \(10-\mathrm{cm}\)-diameter cylinder. Dry air at \(325 \mathrm{~K}\) and \(1 \mathrm{~atm}\) flows at right angle to the axis of the cylinder at a velocity of \(2 \mathrm{~m} / \mathrm{s}\). The liquid is at a temperature of \(315 \mathrm{~K}\) where it exerts a vapor pressure of \(26.7 \mathrm{kPa}\). Estimate the length of the cylinder. For benzene, \(T_{c}=562.2 \mathrm{~K}, P_{c}=48.9 \mathrm{bar}, M=78, V_{c}=259 \mathrm{~cm}^{3} / \mathrm{mol}\), and \(Z_{c}=0.271\) (Reid et al., 1987).