Transesterification of Waste Cooking Oil in Presence of Crushed Seashell as a Support for Solid Heterogeneous Catalyst 2011-01-2226
Developing relatively cheap and widely available resources for
heterogeneous solid catalyst synthesis is a promising approach for
biodiesel fuel industry. Seashell which is essentially calcium
carbonate can be used as a basic support for transesterification
heterogeneous catalysts. In the present investigation, the
alcoholysis of waste frying oil has been carried out using
seashell-supported K₃PO₄ as solid catalyst. The rationale for this
derives from the fact that waste frying oil contains both
long-chain free fatty acids (FFA) and triglycerides (TG) which are
catalyzed on acid and basic sites respectively. Thus, the
K₃PO₄/seashell catalyst may serve the dual role of promoting both
esterification and transesterification reactions. The catalyst was
synthesized following a dipping impregnation of pre-crushed and
calcined seashell in an aqueous solution of K₃PO₄. Samples with
different percentage loadings of K₃PO₄ (5 to 25 wt%) were prepared.
The catalyst samples were characterized (textural and acid-base
properties) and biodiesel production activity was evaluated in a
slurry reactor. The liquid phase composition in the reactor was
determined using gas chromatography-mass spectrometry (GC-MS)
analysis. The effects of different process variables; ethanol:oil
ratio (3:1-15:1), catalyst concentration (10-50 gL-₁ of mixture
oil & ethanol) on the percentage yield of ethyl ester were
assessed.
Reaction data revealed that K₃PO₄/seashell solid supported
heterogeneous catalyst displayed a quite un-common behavior during
the transesterification reaction of waste oils. Although the
catalyst showed the occupation of two different active sties namely
acid and base, its catalytic activity was found to highly
associated to the strength of its basic sites. Catalyst BET surface
area as well as the ratio of basic to acidic site density (BASD)
were found to increase with elevating the amount of K₃PO₄ being
loaded on calcined shells. Optimal ethyl ester yield was achieved
with a catalyst with W = 0.10 which was found to be quite
beneficial achievement in terms of biodiesel economy.
Citation: Al-Zaini, E., Olsen, J., Nguyen, T., and Adesina, A., "Transesterification of Waste Cooking Oil in Presence of Crushed Seashell as a Support for Solid Heterogeneous Catalyst," SAE Int. J. Fuels Lubr. 4(2):139-157, 2011, https://doi.org/10.4271/2011-01-2226. Download Citation