Design and two step process optimization of a reactive distillation column for improving production amount of ethyl acetate and water

In this study, two step optimization was performed for operating conditions of a reactive distillation (RD) column using simulation outputs. The effects of the operating parameters of the RD column, on the ethyl acetate (EtAc) amount as a result of the reaction between ethanol (EtOH) and acetic acid (HAc) were assessed. The response surface methodology (RSM) was applied to determine the optimum operating conditions for the RD column. The two step experimental design used in RSM was created with the Design Expert (DE) program. The Plackett-Burman (PB) design was used to determine the most important parameters affecting on the designed RD column for production of EtAc amount. The most important parameters were determined as HAc feed rate (kmol/h), EtOH feed rate (kmol/h), reflux ratio and temperature (°C). After PB design Central Composite Design (CCD) was applied to determine the optimum operating conditions of these most important parameters for the RD column. ANOVA was used to investigate the interaction between the response and independent variables with the obtained data and 3 dimensional (3D) plots created by the program were interpreted. A second order regression model according to the independent variables for the EtAc amount (response) was developed with DE program. The optimum operating conditions for the designed RD column were obtained as HAc feed rate 149.86 kmol/h, EtOH feed rate 99.99 kmol/h, feed temperature 70 °C and reflux ratio 2.50. The production of EtAc amount which determined with model coefficients and recommended by the program were compared and relative errors between the model results and the predicted values were less than 1%. The obtained results were showed that RSM may be a suitable method for optimization of operating parameters in RD columns.