Apple Plus Case Study
3.1. SIMULATION
In Aspen Plus to study the behavior of any process, the first step is to make the flow sheet converged in steady state so as to define and obtain the characteristic of the process. Once this flow sheet is converged, then it is imported to Aspen plus Dynamics so as to control and study nonlinearity of the system.
Simulation of TAEE etherrification is carried out in Aspen Plus. Firstly, the reactive distillation column is simulated by the module, RadFrac, using NRTL property method. For this purpose, ASPEN PLUS requires the specification of components, property method, feed conditions (flow rate, composition and thermal state), operating pressure, column configuration (number of stages, feed location, reaction stage, types of condenser and reboiler), two operating parameters, and reaction …show more content…
Fig.4. Composition profile in Reactive distillation column using Aspen Plus
Fig.4.Temperature profile in Reactive distillation column using Aspen Plus
4.2 DYNAMIC CONTROL: The converged flow sheet is exported to Aspen plus dynamics and the resultant graph are shown for condenser pressure control with corresponding duty, reflux level control to the corresponding reflux rate and composition control of TAEE in retentate for the side stream flow rate from RD to pervoporation unit.
It is observed that for the purity control in retentate, making a change in the side stream flow rate, results into a very small error leading to the overshoot. Further on repeatedly making large changes to overshoot the target purity, the output i.e. Side stream flow rate oscillates around the set point in a constantly decaying sinusoidal manner. Therefore the system is stable. Fig.5. Composition control using PID controller Fig.6. Condenser pressure control Fig.7. Reflux drum level control
Controller parameters obtained by ITAE and Z-N tuning relation are tabulated in
In Aspen Plus to study the behavior of any process, the first step is to make the flow sheet converged in steady state so as to define and obtain the characteristic of the process. Once this flow sheet is converged, then it is imported to Aspen plus Dynamics so as to control and study nonlinearity of the system.
Simulation of TAEE etherrification is carried out in Aspen Plus. Firstly, the reactive distillation column is simulated by the module, RadFrac, using NRTL property method. For this purpose, ASPEN PLUS requires the specification of components, property method, feed conditions (flow rate, composition and thermal state), operating pressure, column configuration (number of stages, feed location, reaction stage, types of condenser and reboiler), two operating parameters, and reaction …show more content…
Fig.4. Composition profile in Reactive distillation column using Aspen Plus
Fig.4.Temperature profile in Reactive distillation column using Aspen Plus
4.2 DYNAMIC CONTROL: The converged flow sheet is exported to Aspen plus dynamics and the resultant graph are shown for condenser pressure control with corresponding duty, reflux level control to the corresponding reflux rate and composition control of TAEE in retentate for the side stream flow rate from RD to pervoporation unit.
It is observed that for the purity control in retentate, making a change in the side stream flow rate, results into a very small error leading to the overshoot. Further on repeatedly making large changes to overshoot the target purity, the output i.e. Side stream flow rate oscillates around the set point in a constantly decaying sinusoidal manner. Therefore the system is stable. Fig.5. Composition control using PID controller Fig.6. Condenser pressure control Fig.7. Reflux drum level control
Controller parameters obtained by ITAE and Z-N tuning relation are tabulated in