Benzene is to be absorbed from coal gas by means of a wash oil. The inlet gas contains 3% by volume of benzene, and the exit gas should not contain more than 0.02% benzene by volume. The suggested oil circulation rate is 5 kg oil per 1m3 of inlet gas measured at STP. The wash oil enters the tower solute free and the operation is carried out at atmospheric pressure.
The RMM for benzene is 78 and the equilibrium data are:
Benzene in oil (% by wt)
0.05 0.01 0.5 1.0 2.0 2.5 3.0
Equilibrium partial pressure of benzene in gas (mbar)
0.15 0.31 2.0 5.3 13.3 21.4 33.4