Following a textile operation, residual liquid n-hexane initially present in 1.0-mm-thick cloth is to be removed by pulling the cloth continuously through a drying oven where the n-hexane is vaporized and removed. The dry cloth is continuously rolled up at the outlet of the drying oven. The cloth is 0.5 m wide and the length of the oven is 2.5 m. In the oven, air at 20°C and 1 atm flows over both sides across the width of the cloth at a velocity of 1.5 m/s. Assuming that the process is controlled by the external mass transfer resistance, determine the velocity at which the cloth can be pulled through the oven if it is desired to remove 95% of the nhexane and the initial concentration of n-hexane in the cloth is 10 kg/m³.

Neglect the effects of the cloth velocity on the mass transfer coefficient.