1,600,000 actual cubic feet per day (acfd) of natural gas at 50 degrees F and 225 psi containing 50 lb. of water per MMCF (million cubic feet) at standard conditions (14.7 psi and 32 degrees F) are to be dried in an activated bauxite unit consisting of two adsorbers. One unit will be on-stream while the other is being regenerated. It is desired to remove 99.5% of the water. The breakpoint occurs when the dry bed adsorbs 3% water by weight (dry basis). The bulk density of the granular bauxite is 50 lb/ft^3. Experience indicates that a superficial gas velocity through the tower of 30 ft/min is satisfactory. Use a total time on stream of 24 hours to allow for regeneration and cooling of the other tower. Determine the tower dimensions and mass of activated bauxite required in each tower.
The regenerated alumina contains 0.1% water by weight (dry basis). [Note that the water content is given at conditions that are different from the actual operation of the natural gas adsorption system.]