Use of Glycerol from biodiesel production: Conversion to added value products

A detailed study of main stages of a novel no-conventional process to obtain 1,3propanediol (PD) from glycerol (Gly) has been made. Initially the volumetric productivity of Gly fermentation with Klebsiella pneumoniae bacterium was optimized for one and two continuous stages, where was necessary to study the multiplicity of stable steady states for the fermentation system selecting the conditions where higher concentrations of PD are found; and under optimal operation conditions the outlet PD concentration and the global yield are 0.4833 mol/l and 0.5481 molPD/molGly, respectively. For PD recovery from fermentation broth a noconventional separation scheme was proposed, which consists first in a reactiveextraction with iso-butyraldehyde (iBAld) for produce 2-iso-propyl-1,3-dioxane (iPDOx) and water. The iPDOx is removed toward the organic phase by the aldehyde that acts simultaneously as reagent and solvent. The yield of reactive-extraction process is 85%. Finally Static Analysis (SA) for iPDOx hydrolysis system shows that is possible to obtain PD of high purity and recovery the aldehyde at the 88% in a reactive-distillation tower. SA also allowed obtaining the technological configuration of reactive-distillation tower and this technological synthesis was validated starting from simulations to both infinite/infinite and finite/finite (stages/reflux) conditions, using the ASPEN PLUS software. For finite conditions the simulations showed that a conversion of 69% and 97.5% is reached for reflux ratios of 5.73 and 9.5 respectively.