Extraction, fractionaction and purification

CECILIA I PAULO; M. SOLEDAD DIAZ; ESTEBAN A. BRIGNOLE

Proceedings of the 9th conference of supercritical fluids and their application

University of salerno, department of chemical and food engineering. The editor is Prof. Reverchon

Lugar: Fisciano (SA) Italy; Año: 2010; p. 105 - 111

There has been increasing interest on biomass derived ethanol due to the rapid increase in the price of crude oil and the perceived strength of the global demand of petroleum. Downstream from fermentation processes there is a dilute aqueous solution, the so-called beer, containing about 5-12wt% ethanol. Separation of ethanol from beer is an energyintensive process, which takes up a large fraction of the total energy requirement for the whole biorefinery. The potential of near critical fluid extraction and high pressure distillation for separating alcohols from water has been discussed by several authors [1, 2, 3]. In the present work, we propose a rigorous model for three bioethanol dehydration process production (8,000.00-80,000.00-120,000.00 ton/year) with supercritical propane to minimize costs. We further consider alternative integration schemes between process streams within different nonlinear programming (NLP) problems for capital and operating costs minimization. In particular, we analyze integration between a heat pump option for the distillation column top vapor with the beer column, which can provide reduction in total energy consumption, as well as lower operating costs. Thermodynamic predictions are performed with an upgraded Group Contribution with Association Equation of State. We demonstrate that bioethanol dehydration can be a sustainable alternative that is energetically, as well as economically, competitive with other technologies in the production of this biofuel.