EX-21
Example
• In the thermal hydrodealkylation of toluene to benzene ($C_7H_8 + H_2 \rightarrow C_6H_6 + CH_4$), excess hydrogen
minimizes cracking of aromatics to light gases. In practice, conversion of toluene per pass through the
reactor is only 70%. To separate and recycle hydrogen, hot reactor-effluent vapor of 5,597 kmoh at 500
psia (3,448 kPa) and 275°F (408.2 K) is cooled to 120°F (322 K) and partially condensed with phases
separated in a flash drum. If the composition of the reactor effluent is as given below and the pressure is 485
psia (3,344 kPa), calculate equilibrium compositions and flow rates of vapor and liquid, K-values, and the
amount of heat transferred to partially condense the vapor feed, using a process simulation program for both
the SRK and PR equations. Compare the results.
C
Component Mole Fraction
Hydrogen (H) 0.3177
Methane (M) 0.5894
Benzene (B) 0.0715
Toluene (T) 0.0214
1,0000
+ $CH_4$
%70
$CH_3175$
67