Environmental Engineering Reference
In-Depth Information
from the control panel are the charge (resistance) of the dynamometer, the temperature
of the air at the inlet and the outlet, and the temperature of the inlet and outlet of the
lubricant and the cooling water. The experiment consisted of measurement of NO
x
and PM emissions and fuel consumption for different charges of the engine from 0%
to 100% (3.8 kW).
The analyzer (MEXA-754 GE, Horiba) was used to calculate the amounts of
NO
x
in the exhaust gases. The most important aspects of this analyzer were: exhaust
gases measured, NO, NO
2
; units, ppm; range, (0-5,000) ppm; accuracy, ±1%. The
analyzer was connected to the engine through heated lines of exhaust transport
from Signal Instruments Co (type 530/540) and a pre-filter unit (Signal Instruments
Co, Pre-filter Unit 333).
For the analysis of particles in the exhaust gases, the equipment of Joy Manufacturing
Co.; recommended by the Western Precipitation Division was used. The filters where
of Whatman type 934-AH.
Results and Discussion
Biodiesel Quality
The composition of biodiesel after the EN 14214
[1]
specification is summarized in
Table
1
. The transesterification reaction rate is much higher than it was originally
estimated. After the first 10 min of the addition of the catalyst to the reactor, an
almost quantitative conversion of TG to FAME and glycerol takes place. All the time
that the reactor is left running after this initial time, the reactions are reversible
reactions, and the reaction mixture is slowly moving towards equilibrium. The chro-
matograms of the kinetic samples show an initial quantitative conversion of TG to
FAME but after the first minutes the monoglycerides MG (1.29% wt) and diglycerides
DG (0.17% wt) reappear. However, only MG are out of the specification (1.29% wt,
max. 0.80% wt), and consequently also the total glycerol G (0.03% wt, max. 0.02% wt).
The biodiesel produced meets most of the specifications required by the Technical
Regulation EN 14214.
Kinetic Experiment
The % wt of TG, DG, MG, G and FAME are plotted against time in Fig.
2
. The
transesterification reaction is very quick at 60°C and almost all TG were converted
after the first 5 min; MG and DG were transient intermediate species, always at
very low concentrations.
The transesterification reaction could be considered as an irreversible second
order reaction (first order in TG and first order in methanol) which had been solved
as follows. The transesterification reaction had the general form:
