Environmental Engineering Reference
In-Depth Information
soybean oil at 40°C was studied
[12]
. To the best of our understanding, any data
have been published to date on the kinetics of the transesterification of used olive
frying oil catalyzed by sodium methoxide at 60°C to produce biodiesel, which is
the first aim of this paper.
In Spain, edible vegetable oil consumption is approximately 600 ML/year. Most
of this oil (70%) is olive oil that is mainly used for deep-frying processes. According
to the Spanish National Institute of Statistics, about 74 ML of waste olive oil are
collected per year, which is an approximate value since most of the household
waste frying oil is thrown through the drainage. Transesterification of waste olive
oil to produce biodiesel could decrease the waste disposal problem. Studies con-
cerning the exhaust emissions produced by the combustion of pure waste olive oil
biodiesel have been published recently
[13]
, but no data exist to date on the emis-
sions produced by the combustion of blends of waste olive frying oil biodiesel in
5% vol and fossil diesel fuel. The Spanish Government allows petroleum product
operators to blend biodiesel up to 5% vol with conventional diesel fuel without the
need to legally declare this blending.
Nitric oxide (NO) and nitrogen dioxide (NO
2
) are very important in polluted air.
Collectively designated NO
x
, high NO
x
concentrations can cause severe air quality
impoverishment. NO
x
enters the atmosphere as a result of the combustion of fossil
fuels in internal combustion engines. Like carbon monoxide, NO attach to haemo-
globin and reduces oxygen transport efficiency. Particulate matter (PM) exhaust
emissions are also of great concern, since they are involved in acid rain processes
and respiratory diseases. Substantial reduction in PM emissions can be obtained by
addition of biodiesel to diesel fuel. The PM reduction appears to be related to the
amount of oxygen content in the fuel blend
[14]
. This paper also reported the
exhaust emissions from ternary blends of waste olive oil biodiesel (5% vol), ethanol
(5% vol) and fossil diesel fuel, the so called BE-diesel.
Although some studies have been published recently on exhaust emissions of
BE-diesel
[15]
, no data exits on the use of the blends described in our paper, espe-
cially with the use of waste olive oil biodiesel. Ethanol is a low cost oxygenate of
vegetal origin with high oxygen content. However, there are many technical barriers
to the direct use of ethanol in diesel fuel due to the low cetane number of ethanol,
and the poor solubility in cold climates. In fact, diesel engines cannot operate
normally on ethanol-diesel blends without special additives
[16]
. Biodiesel is known
to act as an emulsifier for ethanol, and blending biodiesel and ethanol into a con-
ventional diesel fuel greatly improved the solubility of ethanol in diesel fuel over a
wide range of temperatures
[17]
.
Experimental
Methanol, tetrahydrofuran (THF), sodium, hydrochloric acid and anhydrous sodium
sulphate were all commercial grade and used without further purification. The oil
transesterified in all the experiments was waste olive frying oil of domestic origin.
