22006. Mass transfer in a packed bed Wilke and Hougan (1945) reported the mass transfer in beds of granular solids. Air was blown through a bed of porous celite pellets wetted with water, and by evaporating this water under adiabatic conditions, they reported gas-film coefficients for packed beds. In one run, the following data were reported: With the assumption that the properties of the gas mixture are the same as those of air, calculate the gas-film mass-transfer coefficient using equation (2-90) and compare the result with the value reported by Wilke and Hougan. Answer: 2.1% difference