poster - International Conference of Agricultural Engineering

where:
C 1 = C 2 = specific heat of the alcohol at 45% NPm (0.6 cal/g °C)
m 1 = mass of alcohol at 45% NPm in its natural state, 100g
m 2 = mass of alcohol at 45% cold NPM, 100g
T 1 = Temperature of the alcohol at 45% NPm in natural state, °C
T 2 = Temperature of the alcohol at 45% PMn, cold °C
T 3 = equilibrium temperature of the mixture, °C
Ccal = calorimeter heat capacity (cal/ °C)
Known heat capacity of the calorimeter (Ccal) and the equilibrium temperature T 3, there is
a sample of oil at a temperature T 4 in the calorimeter and stirred for 10 min until a new
equilibrium is achieved at a temperature T 5 . The specific heat of the oil was determined by
the following energy balance of from Eq 4:
where:
moCo(T 4 -T 5 ) = C 1 m 1 (T 5 -T 3 ) + Ccal(T 5 -T 3 ) (4)
m o = mass of the oil, (g)
C o = specific heat of the oil, cal/g °C
C 1 = specific heat of the alcohol at 45% PMn (0.6 cal/g °C)
m 1 = mass of alcohol at 45% NPn in its natural state, 100g
T 3 = equilibrium temperature of the mixture, °C
T 4 = temperature of the oil sample, °C
T 5 = equilibrium temperature of the mixture of oil, °C
3 Results and Discussion
Considering the variable density of the oil, very important for its use, including the
production of biodiesel, it was found that the genotypes behave fairly, but there was a
significant effect at 1% probability by the F test for the temperature factor which rises and
decreases the density of the oil, as seen in Figure 1 and in equation 1, independent of the
genotypes. When high temperature increases the kinetic energy of the molecules, as
explained Rosenberg (1974) citing the law of Stefan, J = σT 4 , ruled to the relationship
between temperature and energy emitted by a body, with I = energy, T = absolute
temperature (273 + ºC) and σ = constant, corresponding to 5.67 x 10 5 energy -2 sec -1 o K -4 .
Castor oil, despite being the most dense that nature has created, this property is reduced
with increasing temperature.
Equation: y = 1,1524 – 0,000642067x (1)
R 2 = 0,948