PROCESS SIMULATION OF SODIUM METHOXIDE PRODUCTION FROM METHANOL AND SODIUM HYDROXIDE USING REACTIVE DISTILLATION COUPLED WITH PERVAPORATION

Abstract

This research investigates production of sodium methoxide, which has been used as a significant catalyst in biodiesel production process, from the reaction of methanol and sodium hydroxide. This work evaluates in various processes for production of sodium methoxide solution in methanol. The processes are simulated using commercial Aspen Plus program. Three processes of manufacturing sodium methoxide include 1) reactor-distillation, 2) reactive distillation-distillation and 3) reactive distillation coupled with pervaporation. The independent variables are studied at atmosphere pressure for each process such as methanol to sodium hydroxide feed mass flow ratios, Bottom rate of reactive distillation, total number of stages and feed stage location of methanol. Using the product specifications, namely, the sodium methoxide of 675 kg/h under 45 wt.% in methanol solution, containing less than 0.1 wt.% water. Then, the performance of all processes are compared. It was found that the suitable methanol to sodium hydroxide feed mass flow ratio for the reactive distillation-distillation and reactive distillation coupled with pervaporation processes is 1.4 while it is 4 for the reactor-distillation. Next, considering the energy consumption, the reactive distillation coupled with pervaporation outperforms the other two systems. The values of the required energy are 2229.37, 35.13 and 34.25 GJ/h for the reactive distillation coupled with pervaporation, reactive distillation-distillation and reactor-distillation processes, respectively. It is clear that the reactive distillation coupled with pervaporation process is the best alternative for production of sodium methoxide from methanol and sodium hydroxide.