Gasoline pre-blending processes for efficient ethanol recovery: effects of process parameters and process modifications for improved performance

Abstract

With over 20 billion gallons of bio-ethanol produced annually, optimization of bio-ethanol production processes is a major priority for sustainability research. Recent research has made great strides toward improving the efficiency of bio-ethanol production through the development of gasoline pre-blending processes which use liquid–liquid phase separation to eliminate excess water with minimal energy input. This paper investigates the effects of process parameters on the performance and efficiency of this class of processes, offering a design basis for engineers developing new processes along with a broader understanding of their potential performance and economic value. Also explored are a range of process modifications capable of improving process performance. It has been found that blending ratio and initial alcohol concentration are the key parameters in determining ethanol recovery, with the number of liquid–liquid contact stages and the temperature also being significant. It has also been shown that temperature-swing decanting can significantly improve alcohol recovery, reducing ethanol losses by as much as 33% in a typical gasoline pre-blending setup.

Keywords:

• Biofuels
• ethanol
• process design
• energy
• fuel

Acknowledgements

The authors would like to thank Institute for the Development of Energy for African Sustainability (IDEAS) and the National Research Foundation of South Africa for providing financial support for carrying out this work. Dr. M.J. Fernandez-Torres thanks the visiting researcher program, at the University of South Africa, for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.