Crude glycerine is viscous liquid with naturally sweet taste and
light yellow to dark brown in color. It is the impure form of refined
glycerine. Crude glycerine is derived from both natural and chemical
feedstocks. Glycerine occurs in combined form in vegetable oils and fats as
triglyceride. It is also found in animal fats. Crude glycerine is obtained as a
byproduct form biodiesel manufacturing plant and oleochemical industries.
The dramatic increase in demand for transportation fuels and
increased environmental concern of people have raised the emphasis for use of
renewal energy for transportation fuels. Biodiesel, one of the renewal fuels
that are being used as a substitute of petroleum fuels have been produced on
large scale. The increase in production of biodiesel has also increased the
production of its main by-product crude glycerine. Crude glycerine contains 80%
of glycerol contents rest is impurities such as methanol, soap, catalyst,
salts, non-glycerol organic matter and water.
Crude glycerine is also produced on large scale from palm based
oleochemicals industries as a by-product. But the glycerine thus produced is
more pure than that of by biodiesel root. In the production of soap noodles glycerine
is produced as a by-product during the saponification of oils and fats with
sodium hydroxide. In the production of fatty acids derived from palm oil, crude
glycerol is also produced as a by-product during esterification of palm oils.
Crude glycerine is obtained from two roots: biodiesel root and
1. Crude glycerine form biodiesel root: Biodiesel
is fatty acid methyl ester (FAME), which is produced by transesterification of
fats and oils obtained from vegetable oils such as palm oil, rapeseed oil,
soyabean oil, sunflower oil, etc. Sodium hydroxide and methanol are mixed in a
tank separately. Feed oil is heated upto 120oC and mixed with the
catalytic mixture of sodium hydroxide and methanol. Final mixture of sodium
hydroxide, methanol and feed oil is fed to a reactor at 120oC and
Triglyceride of fats or oils reacts with methanol in the
presence of sodium hydroxide and produces fatty acid methyl ester and glycerol,
this reaction is called transesterification reaction. The presence of sodium
hydroxide as catalyst speeds up the replacement of glycerol with three methanol
creating three molecules of fatty acid methyl ester which is a biodiesel. Now
the oil is allowed to settle down and since glycerol is much denser than
biodiesel, so it settle at the bottom of the separator and the glycerol is
easily drawn off from bottom of the separator
2. Crude glycerine from oleochemcial root: During
the manufacturing of soap noodles, fats or oils react with sodium hydroxide
resulting in glycerol and soap base, which is a sodium salt of fatty acid. In
this reaction glycerine is produced as a by-product which is more pure than
that of from biodiesel process.
Glycerol is used in medical, pharmaceutical, and personal care
preparations, mainly as a means of improving smoothness, providing lubrication
and as a humectant. It is found in allergen immunotherapies, cough syrups,
expectorants, toothpaste. Glycerol is also a component of glycerin soap.
Polyols: crude glycerine is used to manufacture polyols, which
are used as a raw material for the production of polyurethane. Crude glycerine
is used an alternate to petroleum for the production of polyurethane.
Polyurethanes are used to manufacture flexible and rigid foams.
Feed ingredient: Crude glycerine is used in the production of
animal feed. It is used a source of energy for animals. Crude glycerine has
high absorption rate and it is a good source of energy. Once absorbed by
animals, it is converted to glucose by the enzyme glycerol kinase for energy
production in the liver of animals.