Stream S19 is then introduced into a distillation column, which is simulated by a stream calculator, SC1. In this piece of equipment the separation required must be specified. In this case 99% of the benzene must exit at the overhead and 98.85% of the toluene must exit at the bottom of the separation unit. The temperature and pressure of the overhead and the bottom must be specified in order for the simulation to be properly represented. The temperatures are 112oC and 2.43 bar. The bottoms of this stream calculator S24 is the recycle toluene that is mixed in M1 with the fresh toluene feed. The overhead of this separator is then introduced into another stream calculator SC2, which simulates the condenser and reflux drum and pump of the distillation tower. This stream calculator separates all the hydrogen and methane in the overhead S25, from the toluene and benzene in the bottoms S26. The stream S25 is then combined in a mixer M6 with the rest of the gas that composes the fuel gas. The stream S26 is then introduced into a heat exchanger E4 where the benzene product is cooled down to 38oC before is sent to storage. Table 4 lists the results of the material balance of each stream in the simulation.