22
Alternative Fuels for Transportation
fractions, low-cost petroleum products replaced the vegetable oils for use in
the engines. However, during the energy crisis periods (1970s), the vegetable
oils and alcohols were widely used as engine fuel. Due to the ever rising
crude oil prices and environmental concern, there has been a renewed focus
on the vegetable oils and their derivatives for use in engines.
Vegetable oils have two broad classifications: edible oils (sunflower, soy
bean, palm oil, etc.) and nonedible oils (jatropha, karanji, rubber seed oil,
etc.). Edible type oils are mainly used for food purposes whereas nonedible oils are used for food purposes. The nonedible vegetable oils serve as
an important raw material for the manufacture of soaps, paints, varnishes,
hair oil, lubricants, textile auxiliaries, and various sophisticated products.
After extraction of oil from oil seeds, the oil cakes can be used as cattle feed
and fertilizer. Moreover, these oil cakes can be used as biomass feed stock
for gasification process. Vegetable oils are derived mainly from four sources
(Agarwal 1999). These are
1. Cultivated oil seeds (i.e., groundnut, rape-mustard, soybean, sesame,
sunflower, safflower, castor, and linseed)
2. Perennial oil-bearing materials (i.e., coconut and palm)
3. Derived oil-bearing material (i.e., cottonseed and rice bran)
4. Oil seeds of forest and tree origin (i.e., karanji and rubber seed oil)
Most of the countries are encouraging efforts to cultivate the oil yielding
trees for vegetable oil production. The annual oil seed production of the
world is 390 million metric tonnes in the year 2007. The break up of various
oil seeds is shown in Figure 2.1.
2.2 Characterization of Vegetable Oils
Vegetable oil molecules are triglycerides with unbranched chains of different lengths and different degree of saturation. Diesel is a complex mixture of
thousands of individual compounds, most with carbon numbers between 10
and 22 and mostly of saturates. The natural organic compound in the animal
and vegetable fats are made up of various combinations of fatty acids (in sets
of three) connected to a glycerol molecule, making them triglycerides. Each
molecule of a fatty acid consists of a carboxyl group (oxygen, carbon, and
hydrogen) attached to a chain of carbon atoms with their associated hydrogen atoms. The chain of carbon atoms may be connected with single bonds
of hydrogen between them, making a saturated fat; or it may be connected
with double bonds, making an unsaturated fat. The number of carbon and
hydrogen atoms in the chain are what determines the qualities of that particular fatty acid (Agarwal 1999).
Alternative Fuels for Transportation
fractions, low-cost petroleum products replaced the vegetable oils for use in
the engines. However, during the energy crisis periods (1970s), the vegetable
oils and alcohols were widely used as engine fuel. Due to the ever rising
crude oil prices and environmental concern, there has been a renewed focus
on the vegetable oils and their derivatives for use in engines.
Vegetable oils have two broad classifications: edible oils (sunflower, soy
bean, palm oil, etc.) and nonedible oils (jatropha, karanji, rubber seed oil,
etc.). Edible type oils are mainly used for food purposes whereas nonedible oils are used for food purposes. The nonedible vegetable oils serve as
an important raw material for the manufacture of soaps, paints, varnishes,
hair oil, lubricants, textile auxiliaries, and various sophisticated products.
After extraction of oil from oil seeds, the oil cakes can be used as cattle feed
and fertilizer. Moreover, these oil cakes can be used as biomass feed stock
for gasification process. Vegetable oils are derived mainly from four sources
(Agarwal 1999). These are
1. Cultivated oil seeds (i.e., groundnut, rape-mustard, soybean, sesame,
sunflower, safflower, castor, and linseed)
2. Perennial oil-bearing materials (i.e., coconut and palm)
3. Derived oil-bearing material (i.e., cottonseed and rice bran)
4. Oil seeds of forest and tree origin (i.e., karanji and rubber seed oil)
Most of the countries are encouraging efforts to cultivate the oil yielding
trees for vegetable oil production. The annual oil seed production of the
world is 390 million metric tonnes in the year 2007. The break up of various
oil seeds is shown in Figure 2.1.
2.2 Characterization of Vegetable Oils
Vegetable oil molecules are triglycerides with unbranched chains of different lengths and different degree of saturation. Diesel is a complex mixture of
thousands of individual compounds, most with carbon numbers between 10
and 22 and mostly of saturates. The natural organic compound in the animal
and vegetable fats are made up of various combinations of fatty acids (in sets
of three) connected to a glycerol molecule, making them triglycerides. Each
molecule of a fatty acid consists of a carboxyl group (oxygen, carbon, and
hydrogen) attached to a chain of carbon atoms with their associated hydrogen atoms. The chain of carbon atoms may be connected with single bonds
of hydrogen between them, making a saturated fat; or it may be connected
with double bonds, making an unsaturated fat. The number of carbon and
hydrogen atoms in the chain are what determines the qualities of that particular fatty acid (Agarwal 1999).