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Prospects of biodiesel feedstock as an effective ecofuel source and their challenges 57

Table 3.2 Classification of edible oil crops based on their lifecycle
Annual crops Soybean (Glycine max)
Sunflower (Helianthus annuus)
Safflower
Groundnut
Sesame
Rapeseed
Cotton
Corn
Poppy (Papaver somniferum)
Biennial crops Rapeseed
Perennial crops Oil palm
Coconut
Olive
Chinese Tallow
Hazelnut
Almond
Moringa
Cotton
Walnut
Bay Laurel

monounsaturated, polyunsaturated, and free fatty acid of each of the oils is reported in
Table 3.3.The acid valuesreportedin g/kgofKOHare twice thefree fattyacid valuesin
percentage [19]. Two major specifications establishing the quality requirements for
alkyl ester-based biodiesel fuels are the ASTM D6751 in the United States and the
EN 14214 inEurope [15].ASTM D6751establishes specifications for a biodieselblend
stock for middle distillate fuels (Table 3.4).

3.2.1.1 Groundnut/peanut

Groundnuts are a popular source of food throughout the world, consumed either as
peanut butter or crushed and used for groundnut oil or simply consumed as a confec-
tionary snack. Groundnuts are cultivated in the tropical and subtropical regions of the
world on sandy soils. Yields of groundnut vary from about 400kg to several tonnes per
hectare, depending on the production system, but on the average, the global yield is
2500–2700kg per hectare [30]. Details on soil requirements, required precipitation
and temperature, planting season, maturity duration, major diseases, and pests affect-
ing groundnuts are summarized in Table 3.5.
Arachis oil (peanut oil and groundnut oil) is derived from groundnut seed. It is a
vegetable oil that contains complex fatty acid composition but only a small proportion
of nonglyceride constituents [31]. It is an excellent food oil with good flavor and
has low free fatty acid value. After transesterification, groundnut oil produces biodie-
sel, which has fuel properties (shown in Table 3.6) comparable to that of mineral
diesel and within limits specified by international standards. Peanut oil produced