Methanol ( = 791 kg/m 3 and M = 32 kg/kmol) undergoes evaporation in a vertical tube with a uniform

Methanol (ρ = 791 kg/m³ and M = 32 kg/kmol) undergoes evaporation in a vertical tube with a uniform cross-sectional area of 0.8 cm². At the top of the tube, the methanol concentration is zero, and its surface is 30 cm from the top of the tube (Fig. P14–104). The methanol vapor pressure is 17 kPa, with a mass diffusivity of D_AB = 0.162 cm²/s in air. The evaporation process is operated at 25°C and 1 atm.

(a) Determine the evaporation rate of the methanol in kg/h

(b) Plot the mole fraction of methanol vapor as a function of the tube height, from the methanol surface (x = 0) to the top of the tube (x = L).

Transcribed Image Text:

Methanol, A 0 Diffusion of A Bulk flow Diffusion of B L Air, B