Fabricio Omar Barroso-Muñoz

Implementation of a reactive dividing wall distillation column in a pilot plant

Abstract Based on the knowledge regarding steady state design, optimization and control obtained by using Aspen Plus and Aspen Dynamics process simulators, we have designed and implemented a reactive dividing wall distillation column (DWDC). The column can be used to carry out the equilibrium reaction between ethanol and acetic acid to produce ethyl acetate and water catalyzed by sulfuric acid. The reactive DWDC contains three packed sections and the middle section is the key part in order to minimize the energy consumption. That section contains a wall that can be moved to three positions to manipulate the split of the vapor stream, whereas the split of the liquid stream is achieved by using a side tank. The reactive DWDC contains a reflux valve used to control either the composition of the distillate or the temperature at some point in the first packed section. Also, a reboiler was implemented in the lower section, and the heat duty supplied to it is used to control either the composition of the bottoms product or the temperature in the reboiler. This design was proposed based on both steady and dynamic simulations. The minimum energy consumption was predicted in the steady state simulation; the dynamic simulations indicated that the minimum energy consumption can be achieved in practice by implementing two control loops of temperature (or composition), as described.

Multiplicities in dividing wall distillation columns in the purification of bioethanol: energy considerations

In this paper, we present results about the energy requirements in the reboilers of an extractive dividing wall distillation column and a thermally coupled distillation sequence with a side rectifier for bioethanol dehydration using glycerol as entrainer, and the study generates the appearance of multiple steady states. During the energy optimization of the dividing wall distillation column, using glycerol as entrainer, the recycle streams were varied until the energy consumption in the reboiler was obtained and the multiple steady states can present a difference of up to 400%. This finding is important since we are interested in detecting the optimal energy consumption in order to reduce the environmental impact caused by the usage and production of energy from petroleum. This information is being used in a current pilot plant in order to detect the optimal operation conditions to dehydrate bioethanol.