| Biodiesel is one of the most important biofuels that can be used as an alternative fuel to petroleum diesel, as it offers lower emissions of air pollutants and greenhouse gas. To produce biodiesel, the catalyzed transesterification and esterification reactions must be carried out in a reactor where the two immiscible reactants (oil feedstock and an alcohol-containing catalyst) are brought into contact. Because of the nature of the multiphase reaction, the efficiency or rate of biodiesel production relies heavily on both reaction kinetics and hydrodynamics of liquid-liquid mixing promoted by reactor design and operation. These two fundamental features must be fully understood in order to arrive at an optimized and cost-effective design for a biodiesel reactor system.;This work focuses on extending the knowledge of the hydrodynamic behaviour of alcohol-oil mixing that takes place in a biodiesel stirred reactor. The hydrodynamic feature, namely the interfacial area (ae) between the two reactants, was determined by conducting a series of acid-catalyzed esterification experiments using methanol and oleic acid (or free fatty acid). The experimental data were obtained over ranges of five process conditions: reaction temperature (45 -- 65°C), agitation speed (200 -- 400 rpm), methanol to oil ratio (3:1 -- 9:1 mol/mol), catalyst concentration (0.5 -- 2.0 %), and concentration of free fatty acid in oil feedstock (5 -- 30 %). Effects of these conditions on the interfacial area as well as biodiesel conversion efficiency were quantified. An empirical correlation for the interfacial area was developed as a function of the influential process parameters. |
