Modeling, simulation and control of an internally heat integrated pressure-swing distillation process for bioethanol separation

Ethanol produced from biomass is one of the most promising renewable fuels. However, most of the proposed separation methods use volatile organic compounds as solvents. Because such solvents are environmentally hazardous, new, efficient and sustainable ways of alcohol purification process ought to be developed. Ideally, no solvent should be required for the high purity purification of alcohol aqueous solutions. Therefore, in this work the modeling, simulation and control of an internally heat integrated pressure-swing distillation (IHIPSD) process to separate the ethanol/water azeotropic binary system into a high purity ethanol stream are addressed. By means of the proposed separation process, high-purity ethanol, suitable for use in the transportation sector, is obtained. Despite the high interaction between the column sections, the results show that the proposed separation process can be operated smoothly with an array of PI controllers. Moreover, the purity of ethanol is maintained with the control structure proposed in the face of upsets.