biofuel is clean and green sourece of energy, climatchange is global problem people are looking for clean source of energy.global enegy problem can be minimised by the use of biofuel.
2. What is biofuel?
Biofuels are any liquid, solid or gaseous fuels
produced from organic matter. The
extensive range of organic materials used
for biofuel production includes starch and
sugary plants such as corn, wheat or sugar
cane; oily plants such as rape seed, soya
beans or jatropha; vegetable oils and
animal fats; wood and straw; algae and
organic waste and others.
3. First Generation Biofuels
• The two most common 1st
generation biofuels are
bioethanol from starch or sugar
crops and biodiesel from oil-rich
plants. As these fuels are
primarily derived from crops
which may also be used as food
for animals and humans.
4. Vegetable Oil-Edible vegetable oil is generally not used as fuel, but lower
quality oil can be used for this purpose. Used vegetable oil is
increasingly being processed into biodiesel, or (more rarely) cleaned of
water and particulates and used as a fuel.
Biodiesel- Biodiesel is the most common biofuel in Europe. It is produced
from oils or fats using transesterification and is a liquid similar
in composition to fossil/mineral diesel. Its chemical name is
fatty acid methyl (or ethyl) ester (FAME).
5. • Bioalcohol-:Biologically produced alcohols, most commonly ethanol, and
less commonly propanol and butanol, are produced by the action of
microorganisms and enzymes through the fermentation of sugars or starches
(easiest), or cellulose (which is more difficult).
• Bioethers-:Bio ethers (also referred to as fuel ethers or fuel oxygenates) are
cost-effective compounds that act as octane enhancers. They also enhance engine
performance, whilst significantly reducing engine wear and toxic exhaust
emissions. Greatly reducing the amount of ground-level ozone, they contribute to
the quality of the air we breathe.
• Syngas-: Syngas, a mixture of carbon monoxide and hydrogen, is
produced by partial combustion of biomass, that is, combustion with an
amount of oxygen that is not sufficient to convert the biomass completely
to carbon dioxide and water. Before partial combustion the biomass is
dried, and sometimes pyrolysed.
• The resulting gas mixture, syngas, is itself a fuel. Using the syngas is more
efficient than direct combustion of the original biofuel; more of the energy
contained in the fuel is extracted
6. • Solid Biofuels-:Examples include wood,
sawdust, grass cuttings, domestic refuse,
charcoal, agricultural waste, non-food energy
crops (see picture), and dried manure.
• When raw biomass is already in a suitable form
(such as firewood), it can burn directly in a stove
or furnace to provide heat or raise steam.
• Biogas-:Biogas is produced by the process
of anaerobic digestion of organic material by
anaerobes. It can be produced either from
biodegradable waste materials or by the use
of energy crops fed into anaerobic digesters
to supplement gas yields.
Poplar grown for fuel in the UK.
7. Green diesel
• Green diesel, also known as renewable diesel, is a form of diesel
fuel which is derived from renewable feedstock rather than the
fossil feedstock used in most diesel fuels. Green diesel feedstock
can be sourced from a variety of oils including canola, algae,
jatropha and salicornia in addition to tallow. Green diesel uses
traditional fractional distillation to process the oils, not to be
confused with biodiesel which is chemically quite different and
processed using transesterification.
• “Green Diesel” as commonly known in Ireland should not be
confused with dyed green diesel sold at a lower tax rate for
agriculture purposes, using the dye allows custom officers to
determine if a person is using the cheaper diesel in higher taxed
applications such as commercial haulage or cars.
8. Ethanol yield from selected sugary
materials (sinha and kishore,1991)
Raw material Possible
production(t/ha)
Carbohydrate
content(%)
Ethanol yields
(litre/t)
Beet 40-50 16 90-100
Sugarcane 50-100 13 60-80
Maize 4-8 60 360-400
Wheat 2-5 62 370-420
barley 2-4 52 310-350
9. The three main methods for the
development of biofuels:
1. burning of dry organic wastes
2. energy forestry
3. the fermentation of wet wastes
11. Commercial production of ethanol involves
three steps-:
Wheat straw(500gm)
Cellulosic pulp(400gm)
xylose(40gm)
Glucose(105gm)
ethanol
(10gm) ethanol
(42gm)
1.Preparation of substrate
2. Fermentation
3. Distillation
12. Why Use Biofuels over Fossil
Fuels?
Biofuels - Are They The Future?
What are the benefits of biofuels?
13. Drawbacks of first generation biofuel
• contribute to higher food prices due to competition
with food crops;
• are an expensive option for energy security taking
into account total production costs excluding
government grants and subsidies;
• provide only limited GHG reduction benefits
sugarcane ethanol, and at relatively high costs in
terms of $/tonne of carbon dioxide ($/t CO2) avoided;
• do not meet their claimed environmental benefits
because the biomass feedstock may not always be
produced sustainably;
• are accelerating deforestation (with other potentially
indirect land use effects also to be accounted for);
• potentially have a negative impact on biodiversity;
and
• compete for scarce water resources in some regions.