Design and Control of an Integrated Toluene-Aniline Production Plant a Preliminary Study

Abstract

Abstract-The scope of this research is to emphasize the importance, possibility and benefits about the coupling of exothermic and endothermic reactions. Coupling could be hydration with dehydration, oxidation with reduction and hydrogenation with dehydrogenation. Nonlinear analysis of reactor-separation-recycle shows difficulties in controlling integrated plants when un-reacted reactant is recycled. As a case study simultaneous hydrogenation of Nitrobenzene to Aniline with dehydrogenation of Methyl-cyclohexane to Toluene is investigated. Instead of multi-tubular reactor, the coupled reaction is carried out in a single tube adiabatic reactor, therefore the complex set-up for hydrogenation and large amount of hydrogen to avoid reaction run-away are no longer required. The steady state and dynamic state behaviour of an integrated plant is analysed using AspenPlus and AspenDynamics respectively. On implementing plantwide control structure the change in production rate is studied. The new system is simpler, stable and robust to feed disturbances. The results obtained here are also applicable to other chemical processes of practical relevance.

Improving Heat Efficiency of Aniline Production Process by Modifying Heat Transfer Fluid Looping System in Heating and Cooling Process

“…Simplified basic process flowsheet of hydrogenation of nitrobenzene [14] modification, the heat received by a heat transfer fluid in the reactor product cooling process is used to reheat the recycled hydrogen. The excess hydrogen is separated from the product and then recycled [31]. The reactor output temperature is 310 °C and cooled to 38.7 °C using a mixture of ethylene glycol and water with a mass ratio of 1:1 as the heat transfer fluid.…”

Coupling exothermic and endothermic reactions—Application to combined aniline production/methyl‐cyclohexane dehydrogenation

“…The interaction between the adiabatic reactor and the separation section, due to material recycle, may be the source of undesired nonlinear phenomena (such as instability and parametric sensitivity, which leads to controllability problems. Behavior of integrated systems is analyzed in few studies and found this new process intensification technique feasible and beneficial. This article presents the design of an integrated plant for the combined production of TOL and AN.…”