Page 410 - Advances in Eco-Fuels for a Sustainable Environment

364 Advances in Eco-Fuels for a Sustainable Environment

measured. The dry benzonic acid was used as a fuel to measure the effective heat
capacity of water.

13.2.5.5 Acid value

Acid value or acid number is defined as the number of a milligram of potassium
hydroxide (KOH) required to neutralizing the 1 g of fat substance. In acid value test-
ing, two solutions have to be prepared such as a burette solution and beaker solution.
In the beaker solution, take 1:3 ratio of diethyl ether and ethanol and add <1g of
testing fuel along with two drops of phenolphthalein color indicator. In the burette
solution, 0.1N of KOH solutions is dissolved in deionized water. The burette solution
is titrated with a beaker solution. The standard methods are available to determine the
acid value such as ASTM D974, ASTM D664, and European standard EN 14104.
Acid value or acid number is used to measure the amount of free fatty acid content
present in fat or oil. This parameter directly affects the biodiesel property such as vis-
cosity, density, calorific value, and cetane number. It also affects the engine emission,
performance, and combustion characteristics. Free Fatty acid are more vulnerable to
oxidation which results in the formation of the gel. Because of more unsaturated fatty
acids present in biodiesel.

13.2.5.6 Density

The density is defined as the mass per unit volume. In order to measure the weight of
the sample, an electronic weighing machine is employed having an accuracy of
0.1g. First, the sample whose density has to be measured is taken in 50mL of vol-
ume. Then the sample quantity weight is measured in the electronic weighing machine
and then the process is repeated for 40 and 30mL volume of sample fuel. This is done
to ensure that the value is very accurate.

13.2.6 Fuel properties

The properties of biodiesel-diesel and biodiesel-diesel-alcohol blends are shown in
Tables 13.3 and 13.4. Biodiesel viscosity is 4.76cSt, which is two times greater than
the diesel, but it is 18 times less than the WFO. Higher viscosity will lead to poor
atomization and evaporation of the fuel. Similarly, lower viscous fuel has the problem
of spill out from the injector and pump at lower pressure. Density of biodiesel is
3
876kg/m , which is 4.5% less than WFO and 5.8% higher than diesel. Higher-density
fuels require less space to accommodate more fuel. B100 has the flash point of 160°C,
which is three times higher than the neat diesel. The flash and fire points of the bio-
diesel are met with the ASTM D93 standard, which is safe for transportation. When
the flash point temperature of the fuel is less than the atmospheric temperature, it is not
safe for transportation. The calorific value of the biodiesel is 39.67MJ/kg, which is
higher than the WFO but less than the diesel. The reduction of calorific value of bio-
diesel is due to oxygen presence in the molecular structure. A higher degree of satu-
ration with long-chain fatty acid has higher calorific value. Less calorific value led to
more fuel consumption. The acid value of biodiesel was measured by the titration