Energy efficiency comparison between a conventional tray column and a novel heat-intensified thermosyphon-assisted falling film distillation unit: an assessment for mixtures with different relative volatilities

Abstract

An energy performance comparison between a novel thermosyphon-assisted falling film distillation unit and a conventional tray unit was carried out for three mixtures with different relative volatilities: ethanol-water, acetone-isopropanol, and acetone-water. Experimental data from the pilot-scale plant were used as targets in the simulation runs through the Hysys^® software. Thus, the separation performed in the falling film unit was reproduced in a conventional tray column. The thermosyphon-assisted falling film unit required less energy, with reductions of 24% for acetone-isopropanol, 30% for ethanol-water, and 55% for the acetone-water mixture. The energy-use ratio also showed that for each kW consumed in the falling film unit, the conventional unit would consume 1.33 kW for acetone-isopropanol, 1.44 kW for ethanol-water, and 2.21 kW for acetone-water, based in the same separation. Therefore, this novel distillation apparatus is more advantageous as an energy-saving viable option for separating mixtures with different relative volatilities.

Keywords:

• Energetic comparison
• energy minimization
• falling film distillation
• thermosyphon-assisted technology

Acknowledgments

The authors are grateful to CAPES (Committee for Improvement of Higher Education Personnel), to CNPq (National Council for Scientific and Technological Development), to ANP (National Agency of Petroleum, Natural Gas and Biofuels), to Petrobras (Petróleo Brasileiro S.A.), and UFSC (Federal University of Santa Catarina) for their financial and technological support.