Abstract

Fatty acid esters are currently produced in batch processes. The production of fatty acid esters in a catalytic distillation column is a promising alternative to the conventional sequential process. In the present study, a steady state equilibrium model was developed for the production of iso-propyl palmitate in a catalytic distillation column catalyzed by zinc acetate supported on functionalized silica gel. The model incorporated reaction kinetics and vapor-liquid non-idealities into the MESH (Material balance, Equilibrium relationship, Summation equation and Heat balance) equations. The model was solved with the numerical method coupled with the relaxation method. To ensure the applicability and reliability of the proposed model, it was validated by comparing the simulated results of a similar endothermic fatty acid esterification (decanoic acid with methanol) in a catalytic distillation column, with the published simulation results and the pilot plant data from the literature. The model was capable of predicting the performance of a catalytic distillation column for an endothermic fatty acid esterification.

To ensure the most effective reactive distillation process for the esterification of palmitic acid with iso-propanol, several key design parameters such as reactant ratio, column pressure, number of equilibrium stages, catalyst weight and reflux ratio were investigated by sensitivity analysis. The results showed that the operation at maximum possible pressure is beneficial for this process due to the endothermicity of the reaction. It was found that the reactant ratio of 1.3-1.7 was sufficient to give high palmitic acid conversion without affecting the iso-propyl palmitate purity. It was observed that low reflux ratios resulted in higher conversion of palmitic acid. However, the number of rectifying and stripping stages was of minor importance for the performance of the overall process. The simulation results could serve as the basis of designing a pilot-scale catalytic distillation unit.

Recommended Citation

Chin, Sim Yee; Mohamed, Abdul Rahman; Ahmad, Abdul Latif; and Bhatia, Subhash (2006) "Esterification of Palmitic Acid with Iso-Propanol in a Catalytic Distillation Column: Modeling and Simulation Studies," International Journal of Chemical Reactor Engineering: Vol. 4: A32.
Available at: http://www.bepress.com/ijcre/vol4/A32