9.1 Steady-state simulation and optimization

Steady-state simulation of methyl acetate esterification was carried out using Aspen Plus simulator. Radfrac module, NRTL property method, and other operating conditions such as feed condition, feed location, operating pressure, column configuration including number of stages and reaction stage, type of condenser, type of reboiler, and feed flow rate of the components used are specified in Aspen Plus environment. The specification and other results are included in Table 4. The simulation flow sheet is shown in Figure 6. The product purity is attaining a highest value at the top stage. The composition profile of the column is shown in Figure 7. As shown in figure, the maximum composition of product methyl acetate obtained is 95.4%. The amount of methanol and acetic acid is much lower at the top of the column; this indicates the complete consumption of reactants and formation of product.

The temperature profile of the column is shown in Figure 8. As shown in figure, we can clearly observe that the temperature of the reactive section is higher than the other section; this is because of the exothermic nature of the esterification reaction. Also, temperature of reboiler is higher than the temperature at condenser. As it can be observed from the figure, the condenser temperature which is 57.4°C is lower than reboiler temperature which is 62.7°C. The temperature of the reactive zone is varied between 61.3 and 77.8°C, making it compatible to the exothermic nature of


the esterification reaction. The maximum temperature of the condenser during experiment was 58°C, and the temperature of the condenser obtained from Aspen Plus was 57.4°C, which shows good agreement between experimental and simula-

Reactive distillation exhibits multiple steady-state conditions throughout the operation. This is known as multiplicity of the process. There are two types of multiplicity; one is known as input multiplicity, and the other is known as output multiplicity. This is the condition in which column gives same output for the different sets of process condition. In this paper, we have studied input multiplicity, in which we obtained same output for different input conditions. To analyze the situation, we have performed sensitivity analysis in Aspen Plus simulator.

For sensitivity analysis, we have first chosen molar flow of methyl acetate on the basis of heat duties whose lower and upper bounds are fixed as 1 and 3 kW, respectively. For the second case, we have calculated mass fraction of methyl acetate by

9.2 Sensitivity analysis of methyl acetate RDC

Composition profile of methyl acetate RDC.

tion results.

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Figure 7.

Figure 6.

Flow sheet of methyl acetate RDC.

Reactive Distillation: Modeling, Simulation, and Optimization

DOI: http://dx.doi.org/10.5772/intechopen.85433
