Adsorption on 6 x 10-mesh activated carbon is being considered to recover methyl ethyl ketone (MEK) from an airstream at 25°C and 1 atm. The airflow is 12,000 std ft³/min, and the air has 0.40 lb MEK/1,000 std ft³. If the superficial velocity is 0.5 ft/sand an adsorption cycle of at least 8 h is desired, about what bed dimensions should be used? Assume the bulk density of the carbon is 30 lb/ft³.