Using Thermally Coupled Reactive Distillation Columns in Biodiesel Production

Authors

Nghi Nguyen, University of Nebraska-LincolnFollow
Yaşar Demirel, University of Nebraska-LincolnFollow

ORCID IDs

Demirel 0000-0002-8183-0991

Date of this Version

2011

Citation

Energy: The International Journal (2011) 36: 4,838-4,847

doi: 10.1016/j.energy.2011.05.020.

Comments

Copyright 2011, Elsevier. Used by permission

Abstract

Production of ethyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy by allowing interconnecting vapor and liquid streams between the two columns to elminate reboiler or condenser or both. Here we study the thermally coupled side-stripper reactive distillation and eliminate the condenser of the reactive distillation column. Both the sequences are optimized by using the thermal and hydraulic analyses of the Column Targeting Tools of Aspen Plus simulator. Comparisons of the optimized sequences show that in the thermally coupled sequence, the energy consumption is reduced by 13.1% in the reactive distillation column and 50.0% in the methanol recovery column. The total exergy losses for the columns are reduced by 281.35 kW corresponding to 21.7% available energy saving in the thermally coupled sequence. In addition, the composition profiles indicate that the thermally coupled reactive distillation column operates with the lower concentration of water in the reaction zone which reduces catalytic deactivation.