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Utilization of waste coral for biodiesel production via transesterification of soybean oil
Moradi, G. & Mohammadi, F.
Abstract
In the present study, the waste coral was utilized
as a source of calcium oxide for transesterification of
soybean oil into biodiesel (methyl esters). Characterization
results revealed that the main component of the waste coral
is calcium carbonate which transformed into calcium oxide
when calcined above 700 oC. The Box–Behnken design of
experiment was carried out, and the results were analyzed
using response surface methodology. Calcination temperature,
methanol– soybean oil molar ratio and catalyst
concentration were chosen as variables. The methyl ester
content (wt%) was response which must be maximized. A
second-order model was obtained to predict methyl ester
content as a function of these variables. Each variable was
placed in the three low, medium and high levels (calcination
temperature of 700, 800 and 900 oC; catalyst concentration
of 3, 6 and 9 wt%; methanol-to-oil ratios of
12:1, 18:1 and 24:1). The optimum conditions from the
experiment were found that the calcination temperature of
900 oC, catalyst concentration of 6 wt% and methanol-tooil
ratio of 12:1. Under these conditions, methyl ester
content reached to 100 wt%. The waste catalyst was
capable of being reused up to 4 times without much loss in
the activity.
Keywords
Coral; Biodiesel; Transesterification; Calcium oxide
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