Recycled Gas Flow Control to Optimize Reaction Conversion and the Accomplishment of Heat Integration in Benzene Production through Hydrodealkylation of Toluene

The reaction takes place in a double-bed catalytic reactor which was assumed as two stoichiometric reactors in the simulation, each represents one compartment. The reaction conversion is decreased at high temperature therefore, the reactor temperature was controlled by specifying the flow of required recycle gas which enters in between of two reactor beds. The study was enriched with the improvement of thermal efficiency of the plant by heat integration. For this purpose, a heat exchanger network (HEN) was designed to reduce the utility consumption. Furthermore, the part of recycle gas flow was suggested to utilize as the fuel to the furnace. Such gas flow control allows supplying around 70% of the heat required for increasing the reactor feed temperature to the desire point. As the result, the overall efficiency of the plant is increased by the manipulations of gas flows in the process.