(60n) An Energy Efficient Process Design for Ethyl Levulinate Production Using Double Reactive Distillation Columns

Since the levulinic acid has been identified as one of the 12 most promising biomass-based platform chemicals by the National Renewable Energy Laboratory and the Department of Energy, there is an increasing interest in the processes where levulinic acid is used as the raw material. At the same time, the search for green and sustainable fuel additives gains speed because of the environmental concerns increasing day after day. At this point, ethyl levulinate as a derivative of the biomass-based levulinic acid comes forward in the industry with the potential of being a fuel additive with its high octane number and high oxygen content, since it could decrease gas emissions by increasing the engine efficiency once it is mixed with biodiesel.

There are just a few process design studies in the literature which focus on the production of ethyl levulinate from the biomass-based levulinic acid. The results of those studies show the superiority of excess design to neat design, which includes the excess of ethanol. However, this results in an ethanol-water azeotropic mixture, where water is a by-product of the reaction and ethanol is fed in excess amount. Thus, the separation of these processes are very energy intensive, and they have high operating costs.

The aim of this study is to design a novel process configuration including two reactive distillation columns to produce ethyl levulinate from levulinic acid and ethanol. In this configuration, the esterification reaction takes place in the first reactive distillation column, where ethyl levulinate is taken from the bottoms of column as the main product. The mixture taken from the top of this column is sent into second reactive distillation column, where ethylene oxide is the second feed of this column. The water, produced in the esterification reaction, is consumed in this distillation column by a water-ethylene oxide (EO) reaction. Thus, ethylene glycol is produced as a by-product and taken from the bottoms, while the distillate only includes the unreacted ethanol. The total annual cost of the optimized configuration will be compared with those of different flowsheets studied in the literature. As the final step, a robust control structure will be design to evaluate the dynamic behavior of the process.