100 MMscfd natural gas (molecular weight of 18) is water saturated at 600 psia and 100F & must be dried to -150F dew point. Determine the water content of the gas (inlet & outlet) & amount of water that must be removed. Do preliminary design of a molecular-sieve dehydration system consisting of two towers with down-flow adsorption in one tower and up-flow regeneration in the other. Use 4A molecular sieve of 1/8"beads (i.e., 4x8mesh). The regeneration gas is part of the plant's residue gas (at 600 psia and 100F) & has a molecular weight of 17. The bed must be heated to 500F for regeneration. Base this on a 24-hour cycle consisting of 12 hours adsorbing and 12 hours regenerating (heating, cooling, standby, and valve switching; the heating time is 60% of the regeneration time)