12.16 A polluted air stream flowing at 12,000 acfm at 90 °F and 1 atm

has a concentration of 500 ppm of ethylbenzene (CgH10). Pilot

plant studies of the adsorption process indicate that 11 lb (net) of

ethylbenzene will be adsorbed per 100 lb of carbon during normal

everyday operations.

a. Calculate the minimum amount of carbon needed in one bed

for a two-hour run time. Give your answer in pounds.

b. Assuming this carbon has a bulk density of 25 lb/ft³, and if

the bed must be at least 1.5 feet deep, calculate the superfi-

cial gas velocity in a bed that contains this amount of carbon.

Give your answer in ft/min,

c. Comment on this superficial gas velocity. If it is too high or

too low, determine what you would do to correct it. Be specific

and give dimensions of the re-sized bed. How does the run

time change?