Impact of reactive holdup on process configuration selection: Is a neat reactive distillation column possible for ethyl levulinate production process?

Besides several advantages, biodiesel has some shortcomings which need the utilization of fuel additives. At this point, ethyl levulinate comes forward as one of the alternative fuel additives with its better cold flow properties and high oxygen content. In the literature on ethyl levulinate production processes, excess of a reactant is used to overcome conversion limitations. This results in multi-column process configurations where additional distillation columns besides a reactive column are used to separate excess reactant. In this study, the conceptual design of a cost-effective process configuration including a single reactive distillation column is proposed. This idea is based on the use of a reasonably higher liquid holdup on reactive trays to get significantly higher conversion and eliminate the excess usage of ethanol. As the result, the desired purity of ethyl levulinate is achieved by a neat reactive distillation column which reduces the total annual cost by 34 % compared to the excess ethanol configuration in the literature. In addition, a control structure is designed for this process configuration, and its robustness is evaluated against disturbances in feed flowrate and composition. Dynamic simulation results show satisfactory base-level regulatory control for this neat reactive distillation column.