The document provides a comprehensive overview of biodiesel production from vegetable oils, detailing its historical context, methods of transesterification, and properties. It discusses catalytic and non-catalytic approaches, the recovery of glycerol as a byproduct, and the comparison of biodiesel with traditional diesel fuel. Additionally, it highlights the advantages and disadvantages of biodiesel, including its impact on food supplies and environmental emissions.

1. U N I V E R S I T Y O F A L - Q A D I S I Y A H
C O L L E G E O F E N G I N E E R I N G
C H E M I C A L E N G I N E E R I N G D E P A R T M E N T
B I O D I E S E L F R O M V E G E T A B L E O I L S
B Y
S A D I Q S H A K E R
S U P E R V I S O R
D R . A L I J A Z I E
2 0 2 0 - 2 0 2 1

3. WHAT IT LOOKS LIKE ?

4. HISTORY
The emergence of transesterification dates back to as early as 1846 when
Rochieder described glycerol preparation through ethanolysis of castor oil.
In 1853, scientists E. Duffy and J. Patrick conducted transesterification of
vegetable oil, long before the first diesel engine became functional.
German inventor Rudolph Diesel designed the diesel engine in 1893 with a
revolutionary design in which air could be compressed by a piston to very high
pressure.
The use of vegetable oils as an alternative renewable fuel, competing with
petroleum, was proposed in the early 1980s, but commercial production did not
begin until the late 1990s.

5. GENERAL PROPERTIES OF BIODIESEL

7. HOW IS IT MADE ?

10. TRANSESTERIFICATION
Fatty acids in oils are present in the form of triglycerides. For example, palmitic acid,
oleic acid, and α-linolenic acid can be joined by a glycerol unit to form the following
triglyceride:
In transesterification (or Alcoholysis), triglyceride is reacted with an alcohol(e.g.,
methanol or ethanol) to form esters and glycerol. Acatalyst (e.g., KOH, NaOH) is usually
used to enhance rate and yield of the reaction. Because the reaction is reversible,
excess alcohol is used to shift the equilibrium to the product side

12. 1-CATALYTIC METHODS
Transesterification can be catalyzed by alkalis, acids, or enzymes. Atypical procedure for
the alkali-catalyzed the method is as follows. The catalyst (KOH or NaOH) is dissolved
into methanol by vigorous stirring in a small vessel. Then, this mixture is pumped into a
reactor containing oil. The reactor is heated (71◦C) and vigorously stirred for about 2
hours to complete the transesterification. Upon successful completion of the reaction,
settling of the phases is allowed in which crude glycerin (heaver liquid) collects at the
bottom and biodiesel (lighter liquid, ester) collects at the top. the ester is carefully
washed. Water is added at 5.5% by volume of the ester
and then stirred for 5 minutes, and the glycerin is allowed to settle again.

13. 2-NONCATALYTIC SUPERCRITICAL ALCOHOL METHOD
In order to overcome the problems of conventional transesterification, Kusdiana and
Saka (2001) and Demirbas (2002a, 2003) have proposed esterification of vegetable oil
with supercritical methanol (SCM). This novel, noncatalytic, one-phase (due to a low
dielectric of SCM) process has solved some of the challenges arising
from the two-phase nature of normal methanol/oil mixtures. In the SCM process, the
reaction completes in a very short time and the purification of the product is much
simpler. However, the reaction requires temperatures of 250–400◦C and pressures of
350–600 bar In the transesterification process, vegetable oil should have an acid value
of less than 1, and all the materials should be substantially anhydrous. The higher the
acid value, the more NaOH or KOH is required to neutralize the free fatty acids.

14. 3-RECOVERY OF GLYCEROL
About 10 tons of glycerol is produced for every 100 tons of biodiesel. Hence, worldwide
production of 13 million tons/year of biodiesel has given rise to 1.3 million tons/year of
glycerol. Recovery and use of this byproduct can add value to the biodiesel process.
However, a recent surge of glycerol supply in the market has
significantly depressed its prices. In a steady economic operation, valuable products
can be made from glycerol; hence, its efficient recovery is important. the separation of
biodiesel and glycerin can be achieved using an inexpensive settling tank. If faster
separation is needed, then a centrifuge can be used. The denser phase preferentially
separates to the outer surface of the centrifuge. The choice of appropriate centrifuge
type and size is dependent on the degree of separation needed in a specific system.
Glycerol has been used in a variety of ways, including as a humectant, plasticizer,
emollient, thickener, dispersing medium, lubricant, sweetener, bodying agent,
and antifreeze.

16. VEGETABLE OIL RESOURCES
Vegetable oils have different chemical structures than diesel. Vegetable oils contain
fatty acids that are linked to a glycerin molecule with ester linkages, called a
triglyceride.
World vegetable oil production of about 0.13 billion tons/year is very small
when compared with the world petroleum consumption at 4.25 billion tons/year.

18. COMPARISONS OF FUEL PROPERTIES OF VEGETABLE OILS WITH NO. 2 DIESEL
FUEL

19. ADVANTAGES & DISADVANTAGES OF BIODIESEL
higher viscosity, lower energy content, higher price.
higher CP and PP, higher emissions of nitrogen oxides (NOx)
lower engine speed and power, injector coking, engine compatibility.
A significant disadvantage with biodiesel is that it competes with food supply of
vegetable oil.