18-09-2016, 07:41 AM
design a fixed bed adsorber to treat a gas stream. the feed for the adsorber is supplied at a rate of 10kmol/h at a pressure of 10atm. the stream contains an inert gas A which adsorbs very poorly to the selected adsorbent and a second gas B, which adsoebs strongly to the adsorbent. gas B is 1mol% of the total gas stream. the adsorber will be built out of pipe sections with an internal diameter of 1.5m. the adsorbent used has a bulk density of 420kg/m3 (bed). assume that adsorption of component A only will occur with a constant pattern front, and allow LUB=0.2*LES to make allowances for any mass transfer zone. a langmuir isotherm may be assumed as follows:
Qb(mol/g)=0.00827*Pb/(1+1.388*Pb)
a) what is the loading Q in mol/kg on the bed when the bed is loaded?
b) if idael time to breakthough is 24hrs calculate the mass of adsorbent S required the LES (i.e length of bed that should be fully loaded after t (ideal)) and actual bed length i.e. LES+LUB
c) consider any assumption made (e.g. CPF, LUB=0.2*LES) and think about what the effect on operation and T(ideal) would be if your assumptions are correct.