Waste cooking oil (WCO) is a very attractive raw material for
biodiesel production.
FFA esterification of WCO heterogeneously catalyzed by ion exchange resins in slurry reactor is a convenient and easy-to handle
process to lower acidity. Resins Amberlyst
46 (Dow Chemical) and
Purolite
D5081 demonstrated not to deactivate in WCO even after
several recycles of uses in slurry modality. Carberry-type reactor,
besides preventing deactivation by mechanical stress of the resins
is not suitable for the FFA esterification since a good contact between the reagents and the catalyst cannot be achieved.
Properties of WCO that makes it hard to be processed to biodiesel or that are not in range with limits imposed by the law, can be
improved blending the WCO with other crude oils. In this work the
progressive improvement of the properties of the WCO was
achieved by blending it with increasing amounts of crude rapeseed
oil (CRO). These blends were moreover successfully deacidified by
FFA esterification reaction, showing an increase of the FFA conversion with the content of CRO.
The effect of diesel as a solvent was also investigated, showing
very interesting results. Higher FFA conversions were achieved in
shorter times using diesel as a solvent other conditions being
equal. This opens the opportunity for the use of diesel as a solvent
for oils along the entire weaving factory for biodiesel production,
since solvent separation steps are not required.