7 Technologies for Conversion Bio-Lubricant …
177
usually results in better low-temperature properties. However, high unsaturation in
the molecule weight causes poor oxidative stability. A longer chain length results in
a higher melting point and viscosity. Monounsaturated fatty acids, such as oleic acid
and palmitoleic acid, have low melting point and good oxidative stability. Therefore,
plant oil feedstocks which possess high contents of oleic or palmitoleic acid are
generally preferred in this purpose.
Among the various crops with oil-bearing seeds, non-edible crops are more desirable than edible crops because they grow on land that is largely unproductive and
do not in direct competition with existing edible crops resources. As a non-edible
crop, castor is an excellent renewable feedstock for biomass-based energy products,
such as biodegradable lubricants, bio-polymers, and biodiesel. It is easy to cultivate
under drought, salt, and barren conditions. Besides, castor oil raw material is easy to
scale up. At present, among the bio-energy crops, castor produces the highest yield.
Castor is a key industrial crop cultivated in tropical and subtropical regions of India,
China, and Brazil. Globally, around one million tons of castor seeds are produced
every year, with a worldwide market of over $400 million of castor oil. Currently,
US imports about $41 million worth of castor oil annually.
In recent years, the development and utilization of castor oil has gained wide
attention. Castor is one of the top ten oil crops with high oil content, which is 45–
60% [25]. And it is unique because main of its fatty acid content is ricinoleic acid,
a monounsaturated, 18-carbon fatty acid with a hydroxyl function at 12-position.
It is the only major commercial source of hydroxy fatty acid. Due to the unique
molecular structure and facilely processing of castor oil, it can be considered as a great
alternative to petroleum to produce a wide range of products including lubricants,
coatings, surfactants, plasticizers, cosmetics, pharmaceuticals, polymers, cosmetics,
soaps, inks, fungicides, and others.
With the development of castor technology and industry, green high-performance
lubricants have been developed. Castor-based biodegradable lubricate is a kind of
promising product with high viscosity and nice performance characteristics at low
temperature. Castor oil is the only one which has high content of hydroxy fatty
acid among vegetable oils. Its viscosity at ambient temperature is five times more
than that of most vegetable oils and it also has a high viscosity index. The advantages of castor oil as lubricant base oil covers (1) renewable, non-food biomass; (2)
biodegradable, eco-compatible; (3) outstanding anti-oxidation, anti-wear properties,
low-temperature fluidity, and long life-time; (4) the properties controlled by easily
modifying their structures.
Bio-lubricants are potential alternative lubricants. This chapter gives an overview
of a bio-lubricant based on vegetable oil, especially castor oil. In Sect. 7.2.1,
the source as well as oil extraction methods of the bio-lubricant are discussed.
Section 7.2.2 introduces the main modification methods of raw oil, including biological modification and chemical modification. Additives have a significant influence
on the performance of the lubricating oil. Section 7.2.3 describes the commonly used
additives in bio-lubricants.
177
usually results in better low-temperature properties. However, high unsaturation in
the molecule weight causes poor oxidative stability. A longer chain length results in
a higher melting point and viscosity. Monounsaturated fatty acids, such as oleic acid
and palmitoleic acid, have low melting point and good oxidative stability. Therefore,
plant oil feedstocks which possess high contents of oleic or palmitoleic acid are
generally preferred in this purpose.
Among the various crops with oil-bearing seeds, non-edible crops are more desirable than edible crops because they grow on land that is largely unproductive and
do not in direct competition with existing edible crops resources. As a non-edible
crop, castor is an excellent renewable feedstock for biomass-based energy products,
such as biodegradable lubricants, bio-polymers, and biodiesel. It is easy to cultivate
under drought, salt, and barren conditions. Besides, castor oil raw material is easy to
scale up. At present, among the bio-energy crops, castor produces the highest yield.
Castor is a key industrial crop cultivated in tropical and subtropical regions of India,
China, and Brazil. Globally, around one million tons of castor seeds are produced
every year, with a worldwide market of over $400 million of castor oil. Currently,
US imports about $41 million worth of castor oil annually.
In recent years, the development and utilization of castor oil has gained wide
attention. Castor is one of the top ten oil crops with high oil content, which is 45–
60% [25]. And it is unique because main of its fatty acid content is ricinoleic acid,
a monounsaturated, 18-carbon fatty acid with a hydroxyl function at 12-position.
It is the only major commercial source of hydroxy fatty acid. Due to the unique
molecular structure and facilely processing of castor oil, it can be considered as a great
alternative to petroleum to produce a wide range of products including lubricants,
coatings, surfactants, plasticizers, cosmetics, pharmaceuticals, polymers, cosmetics,
soaps, inks, fungicides, and others.
With the development of castor technology and industry, green high-performance
lubricants have been developed. Castor-based biodegradable lubricate is a kind of
promising product with high viscosity and nice performance characteristics at low
temperature. Castor oil is the only one which has high content of hydroxy fatty
acid among vegetable oils. Its viscosity at ambient temperature is five times more
than that of most vegetable oils and it also has a high viscosity index. The advantages of castor oil as lubricant base oil covers (1) renewable, non-food biomass; (2)
biodegradable, eco-compatible; (3) outstanding anti-oxidation, anti-wear properties,
low-temperature fluidity, and long life-time; (4) the properties controlled by easily
modifying their structures.
Bio-lubricants are potential alternative lubricants. This chapter gives an overview
of a bio-lubricant based on vegetable oil, especially castor oil. In Sect. 7.2.1,
the source as well as oil extraction methods of the bio-lubricant are discussed.
Section 7.2.2 introduces the main modification methods of raw oil, including biological modification and chemical modification. Additives have a significant influence
on the performance of the lubricating oil. Section 7.2.3 describes the commonly used
additives in bio-lubricants.