Glycerol can be produced by using different processes and feedstocks. For example, it can be obtained by propylene synthesis via several pathways [8], by hydrolysis of oil or by transesterification of fatty acids/oils.

1. GLYCEROL
Presented by G.Vijayalakshmi
Presented to Dr.S.Muthukrishnan M.Sc.,M.Phil.,Ph.D.

2. Glycerol(GLYCERIN) is a
colorless, odorless liquid with a
sweet taste. It is viscous at room
temperature and non-toxic in
low concentrations. Glycerol was
discovered in 1779. It is also
called glycyl alcohol, glycerin or
glycerine in some literature.
Discovered in 1779 by Scheele
Fir st major source-spent lye from soap
making process
Primary source for last 20 years-sweet
water from fat splitting (fatty acid
production)

3. •Glycerol also referred as glycerine is a chemical
compound that is generally non-toxic, sweettasting, vicious
liquid.
• The chemical structure shows that each carbon atom is
bonded to a hydroxyl (-OH) group.
•Because ofthis, glycerine is also known as Polyol, which
is an alcohol containing more than one hydroxyl group.
•These hydroxyl groups are also responsible for the
hydroscopic nature of glycerol.
• Its systematic name is prop-1,2,3-triol
• Glycerol was first obtained as a bi-productofsoap
manufacture through saponification offats.

4. OTHER NAMES FOR GLYCERIN
Glycerol
Propane-1,2,3-triol
1,2,3-Propanol
1,2,3-trihydroxypropane
Glyceritol
Glycyl alcohol
Glycerin occurs in combined
form (triglycerides in animal
fats and vegetable oils and is
obtained from these fats and
oils during
transesterification,such as in
biodisel production

5. STRUCTURE &FUNCTIONALITY
A glcerin molecule is an open-ended chain of three carbon atoms
Glycerine contains one secondary and two primary alcohol groups per molecule
Each carbon atom attaches to an OH-ion,also known as a hydroxyl group.
This leaves the glycerine molecule with five available bonds, which are filled with hydrogen
atoms
Reacts with organic and inorganic acids to form aldehydes,esters,ethers and many derivativey
The presence of multiple alcohol groups facilitates the formation of polymers and coatings:
Polyesters,polyethers
Alkyd resins
Non-toxic,water soluble,viscous,Hygroscopic
Acts as both a solvent and reactant.
Useful in the development of green products and
processing technologies
Important characteristics

6. Glycerin properties
-
Melting point -17.8 *C
Boiling popint(1 atm) 290*C
Density (25 degree C) 1.262g/ml
Solubility water,ethanol

7. GLYCEROL PRODUCTION
•Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae.
• When faced with osmotic stress, for example during semi-solid state bread dough
fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by
balancing the intracellular osmolarity with that of the environment.
• However, increased glycerol production also results in decreased CO2 production, which
may reduce dough leavening.
• The common brewer’s and baker’s yeast Saccharomyces cerevisiae limits dehydration by
balancing the intracellular level of osmolytes with the extracellular water activity.
• Specifically in environments with lower water activity compared to the cytoplasm, cells
divert part of the glycolytic flux towards the production of glycerol, while also limiting
glycerol catabolism and efflux and increasing glycerol uptake from the environment
•Glycerol is produced by reduction of the glycolytic intermediate dihydroxyacetone
phosphate to glycerol 3-phosphate (G3P) followed by dephosphorylation of G3P to glycerol

9. •The best-studied pathway for the production of glycerol from other carbon sources starts
with the NADH- dependent reduction of glycolytic DHAP to G3P by a cytosolicglycerol 3-
phosphate dehydrogenase (cG3PDH)
• After which G3P is dephosphorylated to glycerol by a glycerol 3-phosphatase (GPP) .
• This anabolic G3P pathway’ is the major (or exclusive) path-way for glycerol production
in S. cerevisiae during osmo-regulation and anaerobic redox balancing
• In S. cerevisiae, cG3PDH activity is encoded by the two isogenes GPD1 and GPD2, while
GPP activity is encoded by the isogenes GPP1 andGPP2.
• Genes encoding NAD1-dependent cG3PDH have also been characterized in several other
yeast species and filamentous fungi, such as Candida magnoliae
•, Candida glycerinogenes , Debaryomyces hansenii (Thome, 2004) and
A.nidulans (Fillinger et al., 2001).
• In addition, cG3PDH activity using NADPH instead of NADH as the cofactor has been
identified in certain yeast species, such as Candida versatilis

10. • Second pathway for glycerol production using DHAas an intermediate has been proposed in
filamentousfungi (referred to here as the ‘anabolic DHA pathway’,
•The first step in this pathway is assumed tobe catalyzed by a so far uncharacterized enzyme
thatdephosphorylates DHAP to DHA .
The sec-ond step is catalyzed by an NADP1-dependent GDH ofthe type EC .
This anabolic DHA path-way has been postulated based on the fact that NADP-
dependent GDH activities converting DHA to glycerolhave been identified in
S. pombe A. nidulans , A. niger , A.oryzae and H. jecorina .
•The anabolic DHA pathwayis the major pathway responsible for glycerol accumula-tion
during osmoregulation in this organism, while thealternative anabolic G3P pathway did not
•seem to play asignificant role.
• The disruption of gldB encodingNADPH-dependent GDH led to significantly reduced
intracellular glycerol levels.

11. GLYCEROL AS BYPRODUCT DURING BIODIESEL
PRODUCTION
• Glycerol (also known as glycerin) is a major byproduct in the biodiesel
manufacturing process.
• Biodiesel production will generate about 10% (w/w) glycerol as the main
byproduct.
• In general, for every 100 pounds of biodiesel produced, approximately 10
pounds of crude glycerol are created.
• It is projected that the world biodiesel market would reach 37 billion gallons
by 2016, which implied that approximately 4 billion gallons of crude
glycerol would be produced

12. BIODISEL FROM GLYCEROL
 Biodiesel production produce ~10 % w/w of crude glycerol.
 Increase in biodiesel production ,Increase in crude glycerol.
 Surplus crude glycerol,Decrease in price of pure glycerol
 Conversion of crude glycerol into value added products is essential to
maintain the sustainability of biodiesel production.
Composition of crude glyceroL
 Glycerol
 Light solvent (Methanol or ethanol, water)
 Soap
 Fatty acid methyl esters (FAME i.e. biodiesel
 Glycerides (i.e. to mono, di & tri-glycerides),
 Free fatty acids (FFA)
 Ash

13. FACTORS AFFECTING THE COMPOSITION OF CRUDE
GLYCEROL
 Catalyst type used- lipase, alkaline,acidic
 Transesterification efficiency
 Recovery efficiency of biodiesel
 Impurities in feedstock
 Recovery efficiency of methanol and catalyst

15. NEUTRALIZATION
• Most common pretreatment method involves acidifying with Strong
acid to remove Catalyst and Soaps Acid + Soap
• Free fatty acids (skimmed off) Acid + Base catalyst (NaOH, KOH)
Salt + Water Acidification process usually separates the crude
glycerol into 3 layers:
• 1. free fatty acids Top layer (Separated using separated funnel)
• 2. glycerol rich layer Middle &
• 3. Inorganic saltsBottom

16. METHANOL REMOVAL
 Excess methanol is used during transesterification to enhance the yield
 Excess methanol distributes between the methyl-ester and crude glycerol phase.
 However, due to toxicity of methanol on environment & health it has to be
removed and recycled back CG can be treated under vacuum conditions using a
rotary evaporator at 50-90 0C for more than 2 h
 In industry, commonly evaporator or flash unit is employed Falling film
evaporators recommended as best
 As it keeps shorter contact time
 Prevents glycerol decomposition Glycerol concentration after methanol
removal= ~85% 1

17. PURIFICATION AND REFINERY
Vacuum
Distillation
Ion Exchange Adsorption
Adsorption using activated carbon

18. VACUUM DISTILLATION
1
• At higher temperature glycerol property changes,
• >200 0C, Polymerization into polyglycerol
• >160 0C & slightly acidic condition, dehydration
2
• Can oxidize into glycerose, glyceraldehydes and di-
hydroxylacetone
3
• Thus, purification has to be done in vacuum where the pH,
temperature and pressure must be controlled

19. PURIFICATION PROCESS

20. CONCLUSION
 Glycerol purification is the necessary for the sustainability of
biodiesel production
 Various techniques are being explored for purification process
 Even though costly and energy intensive, vacuum distillation
remains the method of choice in most of the prevailing biodiesel
plant
 Membrane separation technology is the emerging technology and
possess a promising future
 Search for more economical purification techniques are still required

21.  Effective utilization of crude glycerol is very crucial for the further
development of the biodiesel production.
 Characterization of crude glycerol is important as impurities present
in it play a major role in crude glycerol conversion.
 Conventional catalysis and biotransformation are the two main
routes for converting the crude glycerol into value added products.
 Extensive studies on biological conversion has produced
encouraging results in the recent past. However, all these conversion
still have to overcome technological hurdles for its practical
implementation on large scale

22. USES OF GLYCEROL
• Large quantity of glycerine is consumed in the manufacture of
nitro-glycerine, cosmetics and medicinal preparations.
• It is also used in the production of printer’s roller and of inks
for use in rubber stamps.
• The hydroscopic properties of glycerol cause it to be used in
keeping tobacco moist and to keep leather soft.
• Glycerol is used in the preparation of personal care products,
such as skin, hair and soap products (23 percent) and in oral
hygiene products, such as toothpastes and mouthwashes (17
percent).

23. CHALLENGES OF CRUDE GLYCEROL
UTILIZATION & PURIFICATION
 Development of new approaches and alternatives as to ensure the
sustainability of biodiesel production industries is still needed.
 Design of economical method for the purification crude glycerol to
more usable state for its utilization.
 Need of improvement in biodiesel production process itself
 less use of alcohol, avoiding using homogeneous catalyst (produce
large amount of salt, large operation cost and expensive separation
procedure).
 To obtain vegetable oil and alcohol with considerably anhydrous
properties and have a low free fatty acid content, because the
presence of water or free fatty acid or both promotes soap
formation.

24. ADVANTAGES OVER OTHER CONVENTIONAL
METHODS
It uses relatively lower energy compared to distillation, reverse
osmosis and pervaporation
Lower membrane fouling
Lower operating pressure compared to pressure-driven membrane
and lower operating temperature in comparison with conventional
evaporation.

25. •Some of the products that include glycerol are moisturiser, detergents, hair colouring
agents, mascara, nail polish remover, perfumes, body lotions, hair spray, shaving cream,
lipsticks, cough medicines, shampoos and hair conditioner.
• It is used in the manufacture of explosives.
• Used in the production of a variety of plastics and players, such as polyetherpolyols, urethanes
and alkyd resins.
•Used as a lubricant in pumps, bearings, gaskets and other mechanical systems.
• Used as an emulsifying agent.
• Used as an antifreeze
• Used in number of medical applications, such as treatment of glaucoma and stroke.

26. •The most common use of glycerol in USA is I food products, where it acts as a sweetener
and as a thicker in many foods.
• For example, it is added to ice cream to improve the texture and to candy products and
baked goods to increase the sweetness of the product.
•Glycerol is used as a solvent for flavors and food colors. It is also used as a humectant,
plasticizer, emollient, sweetener, and filler in low-fat food products such as cookies.