2. 080820
Sustainable means using less than is renewed; if water is withdrawn from a dam
faster than it is refilled, the level drops and hydro power is lessened, and finally fails
Non
renewable
Renewable
Conventional Coal
Oil
Gas
Nuclear
Fission
Wood
Hydro
Human/Animal
Wind Water Pumping
Alternative Geothermal
Oil Shale, CTL
Tar Sands
Methane
Hydrates
Wind Solar
Wave/Tide
Ocean Current
Biofuel
3. Fossil Fuels
• Why are we looking for a replacement
fuel’s like Biodiesel?
7. CONTENTS
I. What is bioethanol?
II. Bioethanol Production
III. Fuel Properties
IV. Application
V. Advantages
VI. Disadvantages and Concerns
VII.Comparison of Bioethanol and
Biodiesel
VIII.Future development
8. What is Bioethanol
Bioethanol is an alcohol made
by fermentation, mostly
from carbohydrates produced
in sugar or starch crops such
as corn or sugarcane. Cellulosic biomass,
derived from non-food sources such as trees
and grasses, is also being developed as
a feedstock for ethanol production
9. Contd.
The principle fuel used as a petrol substitute is bioethanol
Bioethanol fuel is mainly produced by the sugar or cellulose
fermentation process
Ethanol is a high octane fuel and has replaced
lead as an octane enhancer in petrol
10. Bioethanol Production
• Wheat/Grains/Corn/Sugar-cane can be used to
produce ethanol. (Basically, any plants that composed
largely of sugars)
• Bioethanol is mainly produced in three ways.
• Sugar ethanol
• starch sugar ethanol
• cellulose and hemicellulose ethanol
11. Bioethanol Production
• Concentrated Acid Hydrolysis
– ~77% of sulfuric acid is added to the dried biomass
to a 10% moisture content.
– Acid to be added in the ratio of 1/25 acid :1
biomass under 50°C.
– Dilute the acid to ~30% with water and reheat the
mixture at100°C for an hour.
– Gel will be produced and pressed to discharge the
acid sugar mixture.
– Separate the acid & sugar mixture by using a
chromatographic column .
12. Bioethanol Production
• Dilute Acid Hydrolysis
– oldest, simplest yet efficient method
– hydrolyse the bio-mass to sucrose
– hemi-cellulose undergo hydrolysis with the
addition of 7% of sulfuric acid under the
temperature 190°C.
– to generate the more resistant cellulose
portion, 4% of sulfuric acid is added at the
temperature of 215°C
13. Bioethanol Production
• Wet milling process
– corn kernel is soaked in warm water
– proteins broken down
– starch present in the corn is released
(thus, softening the kernel for the milling process)
– microorganisms, fibre and starch products are
produced.
– In the distillation process, ethanol is produced.
14. Bioethanol Production
• Dry milling process
– Clean and break down the corn kernel into fine
particles
– Sugar solution is produced when the powder
mixture (corn germ/starch and fibre) is broken
down into sucrose by dilute acid or enzymes.
– Yeast is added to ferment the cooled mixture into
ethanol.
15. Bioethanol Production
• Sugar fermentation
– Hydrolysis process breaks down the biomass
cellulosic portion into sugar solutions which will
then be fermented into ethanol.
– Yeast is added and heated to the solution.
– Invertase acts as a catalyst and convert the sucrose
sugars into glucose and fructose. (both C6H12O6).
16. Bioethanol Production
Chemical reaction 1
The fructose and glucose sugars react with zymase
to produce ethanol and carbon dioxide.
Chemical reaction 2
Fermentation process requires 3 days to complete
and is carried out at a temperature of between
250°C and 300°C.
17. Bioethanol Production
• Fractional Distillation Process
– After the sugar fermentation process, the ethanol
still does contain a significant quantity of water
which have to be removed.
– In the distillation process, both the water and
ethanol mixture are boiled.
– Ethanol has a lower boiling point than water,
therefore ethanol will be converted into the vapour
state first condensed and separated from water.
18. Feedstocks
• Sugar is required to produce ethanol by
fermentation.
– Plant materials (grain, stems and leaves) are
composed mainly of sugars
– almost any plants can serve as feedstock for ethanol
manufacture
• Choice of raw material depends on several
factors
– ease of processing of the various plants available
– prevailing conditions of climate
– landscape and soil composition
– sugar content
Crops used in Bioethanol production
Brazil sugar cane
USA corn
India
Europe
sugar cane
wheat and barley
19. Conversion of starch to sugar and then
sugar to ethanol
Eg:-1) wheat
Fermentation conditions
Temperature - 32˚C and 35˚C
pH - 5.2.
Ethanol is produced at 10-15% concentration and the solution is distilled to
produce ethanol at higher concentrations
20. Eg:- 2) sugar cane
Simplest of all the processes
• Fermentation conditions are similar to the above process
21. • This is usually done using molasses.
• Molasses is a thick dark syrup produced by boiling down juice from
sugarcane; specially during sugar refining.
• As molasses is a by product, ethanol production from molasses is
not done in a large scale around the world.
The main reaction involved is fermentation
C6H12O6
sugar (e.g.:-glucose)
2 C2H5OH
ethanol
2 CO2
carbon dioxide
+
yeast
Direct conversion of sugar to ethanol
22. The top five ethanol producers in 2010
Brazil - 16500 billion liters
The United States -16270 billion liters
China - 2000 billion liters
The European Union - 950 billion
liters
India - 300 billion liters
23. Bioethanol Properties
Colourless and clear liquid
Used to substitute petrol fuel for road transport
vehicles
One of the widely used alternative automotive fuel in
the world (Brazil & U.S.A are the largest ethanol producers)
Much more environmentally friendly
Lower toxicity level
24. Fuel Properties
• Reid vapour pressure
(measure for the volatility
of a fuel)
– Very low for ethanol,
indicates a slow
evaporation
– Adv: the concentration of
evaporative emissions in
the air remains relatively
low, reduces the risk of
explosions
– Disadv: low vapour pressure
of ethanol -> Cold start
difficulties
– engines using ethanol
cannot be started at temp <
20ºC w/o aids
Fuel Properties Gasoline Bioethanol
Molecular weight
[kg/kmol]
111 46
Density [kg/l] at 15⁰C 0.75 0.80-0.82
Oxygen content [wt-
%]
34.8
Lower Calorific Value
[MJ/kg] at 15ºC
41.3 26.4
Lower Calorific Value
[MJ/l] at 15ºC
31 21.2
Octane number
(RON)
97 109
Octane number
(MON)
86 92
Cetane number 8 11
Stoichiometric
air/fuel ratio [kg air/kg
fuel]
14.7 9.0
Boiling temperature
[ºC]
30-190 78
Reid Vapour
Pressure [kPa] at
15ºC
75 16.5
25. Fuel Properties
• Octane number
– Octane number of ethanol
is higher than petrol
– hence ethanol has better
antiknock characteristics
– increases the fuel
efficiency of the engine
– oxygen content of ethanol
also leads to a higher
efficiency, which results in
a cleaner combustion
process at relatively low
temperatures
Fuel Properties Gasoline Bioethanol
Molecular weight
[kg/kmol]
111 46
Density [kg/l] at 15⁰C 0.75 0.80-0.82
Oxygen content [wt-
%]
34.8
Lower Calorific Value
[MJ/kg] at 15ºC
41.3 26.4
Lower Calorific Value
[MJ/l] at 15ºC
31 21.2
Octane number
(RON)
97 109
Octane number
(MON)
86 92
Cetane number 8 11
Stoichiometric
air/fuel ratio [kg air/kg
fuel]
14.7 9.0
Boiling temperature
[ºC]
30-190 78
Reid Vapour
Pressure [kPa] at
15ºC
75 16.5
26. Application
• transport fuel to replace gasoline
• fuel for power generation by thermal combustion
• fuel for fuel cells by thermochemical reaction
• fuel in cogeneration systems
• feedstock in the chemicals industry
27. Application
• Blending of ethanol with a small proportion of a
volatile fuel such as gasoline -> more cost effective
• Various mixture of bioethanol with gasoline or
diesel fuels
– E5G to E26G (5-26% ethanol, 95-74% gasoline)
– E85G (85% ethanol, 15% gasoline)
– E15D (15% ethanol, 85% diesel)
– E95D (95% ethanol, 5% water, with ignition improver)
28. Advantages
• Exhaust gases of ethanol are much cleaner
– it burns more cleanly as a result of more complete
combustion
• Greenhouse gases reduce
– ethanol-blended fuels such as E85 (85% ethanol and 15%
gasoline) reduce up to 37.1% of GHGs
• Positive energy balance, depending on the type of raw
stock
– output of energy during the production is more than
the input
• Any plant can be use for production of bioethanol
– it only has to contain sugar and starch
• Carbon neutral
– the CO2 released in the bioethanol production process
is the same amount as the one the crops previously
absorbed during photosynthesis
29. Advantages
• Decrease in ozone formation
– The emissions produced by burning ethanol are less reactive with
sunlight than those produced by burning gasoline, which results in a
lower potential for forming ozone
• Renewable energy resource
– result of conversion of the sun's energy into usable energy
– Photosynthesis -> feedstocks grow -> processed into ethanol
• Energy security
– esp. Countries that do not have access to crude oil resources
– grow crops for energy use and gain some economic freedom
• Reduces the amount of high-octane additives
• Fuel spills are more easily biodegraded or diluted
to non toxic concentrations
30. Disadvantages and Concerns
• Biodiversity
– A large amount of arable land is required to grow
crops, natural habitats would be destroyed
• Food vs. Fuel debate
– due to the lucrative prices of bioethanol some
farmers may sacrifice food crops for biofuel
production which will increase food prices around
the world
• Carbon emissions (controversial)
– During production of bioethanol, huge amount of
carbon dioxide is released
– Emission of GHGs from production of bioethanol is
comparable to the emissions of internal-
combustion engines
31. Disadvantages and Concerns
• Not as efficient as petroleum
– energy content of the petrol is much higher than bioethanol
– its energy content is 70% of that of petrol
• Engines made for working on Bioethanol cannot be
used for petrol or diesel
– Due to high octane number of bioethanol, they can be
burned in the engines with much higher compression ratio
• Used of phosphorous and nitrogen in the
production
– negative effect on the environment
• Cold start difficulties
– pure ethanol is difficult to vaporise
32. Disadvantages and Concerns
• Transportation
– ethanol is hygroscopic, it absorbs water from the air and thus
has high corrosion aggressiveness
– Can only be transported by auto transport or railroad
• Many older cars unequipped to handle even 10%
ethanol
• Negatively affect electric fuel pumps by increasing
internal wear and undesirable spark generation
33. Future development
• For bioethanol to become more sustainable to
replace petrol, production process has to be more
efficient
– Reducing cost of conversion
– Increasing yields
– Increase the diversity of crop used
• As microbes are use to convert glucose into sugar
which is ferment in bioethanol
– Microbiology and biotechnology will be helpful in the
genetic engineering
35. Overview
• Introduction
• The Chemistry of Biodiesel
• Advantages and Disadvantages
• Biodiesel Feedstocks
• Oil Processing
• Small Scale Biodiesel Production
– On-farm Case Studies
• Fuel-making demonstration
36. What is Biodiesel?
• Alternative fuel for diesel engines
• Made from vegetable oil or animal fat
• Meets health effect testing (CAA)
• Lower emissions, High flash point (>300F), Safer
• Biodegradable, Essentially non-toxic.
• Chemically, biodiesel molecules are mono-alkyl
esters produced usually from triglyceride esters
Fatty Acid
Alcohol
Glycerin
Vegetable Oil
BiodieselFA
FAFA
FA
37. Chemistry of Triglycerides
• Biodiesel is made from the combination of a triglyceride
with a monohydroxy alcohol (i.e. methanol, ethanol…).
• What is a triglyceride? Made from a combination of
glycerol and three fatty acids:
38. Transesterification
While actually a multi-step process, the overall
reaction looks like this:
CH2OOR1 catalyst CH2OH
| |
CHOOR2 + 3CH3OH 3CH3OORx + CHOH
| |
CH2OOR3 CH2OH
Triglyceride 3 Methanols Biodiesel Glycerin
R1, R2, and R3 are fatty acid alkyl groups (could be different, or the
same), and depend on the type of oil. The fatty acids involved
determine the final properties of the biodiesel (cetane number, cold
flow properties, etc.)
39. Individual step of Transesterification
First step, triglyceride turned into diglyceride,
methoxide (minus Na) joins freed FA to make
biodiesel, Na joins OH from water (from methoxide
formation) to make NaOH. Other H joins the
diglyceride.
H O H
| | |
HCOR1 H HCO H O
| | | | |
HCOOR2 + HCONa +H2O CHOOR2 + HCOR1 + NaOH
| | | |
HCOR3 H HCOR3 H
| | | |
H O H O
Triglyceride + Methoxide + H2O Diglyceride + Biodiesel + NaOH
40. Transesterification
(the biodiesel reaction)
Fatty Acid Chain
Glycerol
Methanol
(or Ethanol)
One triglyceride molecule is converted
into three mono alkyl ester (biodiesel)
molecules
Biodiesel
Triglyceride
41. Characteristics of Biodiesel
• Liquid varying in color
• Immiscible
• High boiling point of 360–640°F (182–
338°C)
• Low vapor pressure: < 2 mmHg
• Flash point 199°F (93°C)
42. Characteristics of Biodiesel
• Specific gravity between 0.86 & 0.90
• Vapor density > 1
• Less hazardous in terms of
flammability
43. Uses of Biodiesel and Biodiesel
Blends
• Fuel for vehicles
most common use
• Heating fuel in
commercial &
domestic boilers:
– Bioheat
Property of DOE, reprinted with permission
44. Comparison of Bioethanol and Biodiesel
Bioethanol Biodiesel
Process Dry-mill method: yeast, sugars and
starch are fermented. From starch, it is
fermented into sugar, afterwards it is
fermented again into alcohol.
Transesterification: methyl esters and
glycerin which are not good for engines,
are left behind.
Environment
al Benefit
Both reduce greenhouse gas emissions as biofuels are primarily derived from crops
which absorb carbon dioxide.
Compatibility ethanol has to be blended with fossil fuel
like gasoline, hence only compatible
with selected gasoline powered
automobiles.
Able to run in any diesel generated
engines
Costs Cheaper More expensive
Gallons per
acre
420 gallons of ethanol can be generated
per acre
60 gallons of biodiesel per acre
soybeans
cost of soybean oil would significantly
increase if biodiesel production is
increased as well.
Energy provides 93% more net energy per
gallon
produces only 25% more net energy.
Greenhouse-
gas
Emissions
(GHG)
12% less greenhouse gas emission than
the production and combustion of
regular diesel
41% less compared to conventional
gasoline.
45. Biodiesel-Blended Fuels
• Can be used
alone / blended
• B20: 20% biodiesel
• B99: 99% biodiesel
• B100: pure
biodiesel
Property of DOE, reprinted with permission
47. Advantages of Biodiesel
• Requires no engine modifications (except
replacing some fuel lines on older engines).
• Can be blended in any proportion with
petroleum diesel fuel.
• High cetane number and excellent lubricity.
• Very high flashpoint (>300°F)
• Can be made from waste restaurant oils
and animal fats
51. Vegetable Oil as Feedstocks
• Oil-seed crops are the focus for
biodiesel production expansion
• Currently higher market values
for competing uses constrain
utilization of crops for biodiesel
production
• Most oil-seed crops produce
both a marketable oil and meal
– Seeds must be crushed to
extract oil
– The meal often has higher
market value than the oil
52. Biodiesel Feedstocks
1 Biodiesel Magazine, Feb. 2007
2 O’Brian, Richard D. Fats and Oils: Formulating and Processing for Applications, 2004
Land Crop Yields based on US average 2006
Crop Avg Harvest
(lbs)
Oil content
% (avg)2
Gal/acre
(approx.)
Peanut 2874 47 175
Canola 1366 43 76
Soybean 2562 19 63
Sunflower 1211 40 63
Camelina1 1300 35 59
Safflower 1069 33 46
Corn 8946 4 46
Cottonseed 819 19 20
53. Oil Processing
• Oil-seed crops must be crushed to extract
oil
– This can be done on-farm or at a crushing
facility
– Small scale systems use mechanical crushing
– Commercial crushers often also use hexane
extraction
• Hexane is toxic but removes >99% of oil
• Before conversion oil must be degummed:
– Treat with phosphoric acid for 4-8 hours (300-
1000 ppm for soy, 1000-3000 ppm for canola)
– Water Wash
– Vacuum Drying
– Oil often purchased as “Crude, degummed.”
RBD = Refined, Bleached, Deoderized
56. Disadvantages of biodiesel
• Lower Energy Content
– 8% fewer BTU’s per gallon, but also higher cetane #,
lubricity, etc.
• Poor cold weather performance
– This can be mitigated by blending with diesel fuel or with
additives, or using low gel point feedstocks such as
rapeseed/canola.
• Stability Concerns
– Biodiesel is less oxidatively stable than petroleum diesel
fuel. Old fuel can become acidic and form sediments and
varnish. Additives can prevent this.
• Scalability
– Current feedstock technology limits large scalability
61. Jatropha
• Biodiesel from Jatropha
• Seeds of the Jatropha nut is
crushed and oil is extracted
• The oil is processed and
refined to form bio-diesel.
62. Jatropha can be cultivated anywhere
along canals,roads,railway tracks, on
border of farm and even an alkaline soils.
Grown in high as well as low rainfall.
In high rainfall yield is more.
Occurs mainly at lower altitude(0-500Cm)
with average annual temperature above
200C,
and rainfall of 300-1000mm.
68. Bio Mass
• Biomass already supplies 14 % of the world’s
primary energy consumption. On average, biomass
produces 38 % of the primary energy in developing
countries.
• USA: 4% of total energy from bio mass, around
9000 MW
• INDIA is short of 15,000 MW of energy and it costs
about 25,000 crores annually for the government to
import oil.
69. • Bio Mass from cattle manure, agricultural waste,
forest residue and municipal waste.
• Anaerobic digestion of livestock wastes to give bio
gas
• Digester consumes roughly one third the power it’s
capable of producing.
• Fertilizers as by product.
• Average electricity generation of 5.5kWh per cow
per day!!
71. What is a Biodigester?
• A device that mimics the natural decay process of organic matter
• Biogas is produced from anaerobic decay (decay that occurs without
oxygen)
72. Anaerobic Digestion in a Biodigester
• Digester is fed a mixture of water and waste
called a slurry
• Daily, fresh slurry is added, displacing previous
days load that bacteria have started to digest
• First, digestible organic matter is broken down
by acid-producing bacteria
• By-products are then broken down by methane-
producing bacteria
(journeytoforever.org/biofuel_library/)
73. Biogas: Green Energy
• 50-70% methane;
• 30-40% carbon dioxide;
• Insignificant amounts of oxygen and hydrogen
sulfide (H2S).
• Biogas burns without soot or ash being produced
• Methane is a combustible gas
• Biogas will be used to generate energy for the
cooking needs here at Rosalie Forest Eco Lodge
(plascoenergygroup)
74. How Much Biogas Can I Get From My Waste?
• Amount of biogas depends on the waste itself and design of the
digester.
• Some digesters can yield 20 liters of biogas per kilogram of waste up to
800 liters per kilogram.
• Factors: digester design, temperature, system operation, presence of
oxygen.
75. How Much Energy is in Biogas?
• Average fuel value of methane = 1000 BTU/ft3
• Average fuel value of propane = 2500 BTU/ft3
• 1 BTU/ft3 = 37.2589 KJ/m3
76. How Much Energy is in Biogas?
• Therefore, using the SI system, Fuel Value units:
• FV methane = 1000 * 37.2589 KJ/m3 = 37258.9 KJ/m3
• FV propane = 2500 * 37.2589 KJ/m3 = 93147.3 KJ/m3
• FV propane / FV methane = 2.5
• When both fuels are burned completely, propane produces 2.5 times
more energy per unit of volume.
77. How Much Biogas Do I Need?
• For Example: We want 40 lbs of propane-equivalent per week.
• Biogas is 50-70% methane, 30-50% CO2 and 5-15% N2, H2, etc.
• 40 lbs propane * 2.5 = 100 lbs of methane
• 100 lbs of methane / 60% = 166.67 lbs of biogas
78. How to calculate Organic Loading Rate (OLR)
• OLR = kg VS added / day / m3 reactor
• Organic Loading Rate: 2.02 kg VS added / day / m3 reactor
81. Design of digester
• Motors for collectors operate every three hours and has a power
of 1 Kwatt.
• Dry mass tank construct from galvanized steel plate, has a
dimension of 1.5 X 1.5 X 2 .
• Screw pump feeding once a day , has a velocity of 1 m/s, flow
rate 50 L/s.
• Digester size is calculated depending on the equation :
Vd (m3) = Sd (m3/day) * RT (days)
Substrate input (Sd) = biomass (B) + water (W) (m3/d)
• Digester size equals to 320 m3 , for factor of safety it assumed to
be 430 m3 .
• Gasholder size is calculated depending on the equation :
Vg1 = Gc max* Tc max
• Gasholder size equals to 240 m3 .
82. Environmental Benefits
•Reduction of waste
• Extremely low emission of greenhouse gases compared to
fossil fuels
• Ethanol is Carbon neutral and forms a part of the carbon cycle
• Growing variety of crops increases bio-diversity
88. Bio-refinery
• A facility that integrates biomass
conversion processes and equipment
to produce fuels, power, and
chemicals from biomass.
• Analogous to today's petroleum
refineries
• It is based on the “Sugar Platform“
and the “Thermochemical Platform“
Notes de l'éditeur
Methane burns with a light blue flame, barely visible. No soot or ashes are produced
