A Fuel is defined as a combustible substance containing carbon as a major
constituent which is able to produce a large amount of heat, that can be
used for domestic and industrial purpose.
Bio-Fuel: Bio-fuels are fossil-fuels substitutes that can be made from a range
of agricultural crops and other source of Bio-mass.
Any Hydro-carbon fuel that is produced from organic matter
They are considered as an alternative source of energy
Energy security – increase oil price , need for alternative source of energy
To decrease greenhouse gas emission
To promote rural development
In 1980s Rudolf Diesel was a first person who made biodiesl from vegetable
◍ Can be used pure
◍ Biodiesel has no
sulphur content ,and so
it doesn’t contribute
to acid rain formation
◍ Biodiesel has good
better than standard
◍ Biodiesel is
expensive compared to
◍ Biodiesel can release
nitrogen oxide which
can lead to the
formation of smog
◍ Food shortage can be
Advantages & Disadvantages
4. Why Biofuels?
• Biofuel can help to improve
• Can help to improve energy
balance through domestic
• The plants are used to produced
biofuel in replacement of
imported crude oil
• Biofuel will also add to the
overall national capacity to
reduce the need for import oil
5. Biology and Synthesis
When dealing with fossil fuels, the processes are all chemical or
physical. What is more, fossil fuels aren’t really produced so
much as they are refined. All industry really does is refine the
petroleum in order to separate out the parts.
The same is not true of biofuels. Before a biofuel can ever be
used, the feedstock first has to be produced. In many cases,
organisms are genetically modified to improve yield and to
reduce nutrient and water requirements. After that, biofuel is
either refined from oil or produced by algae and harvested. In
either case, complex chemistry is involved to get useful fuels
out of biological molecules 5
Based on Food & Agricultural Organization
Classification of Biofuel Sources
8. Classification According to Generations
Biofuels are generally classified as first, second and third generations:
First-generation biofuels are made from sugar, starch, vegetable oil, or
animal fats using conventional technology. These are generally produced
from grains high in sugar or starch. Common first-generation biofuels include
vegetable oils, biodiesel, bio-alcohols, biogas, solid biofuels, syngas.
Second-generation biofuels are produced from non-food crops, such as
cellulosic biofuels and waste biomass (stalks of wheat and corn, and wood).
Research continues on second-generation biofuels including biohydrogen, bio
methanol, DMF (Dimethyl formamide), Bio-DME (Dry Malt Extract), Fischer-
Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel.
Third-generation biofuels are produced from extracting oil of algae –
sometimes referred to as “oilgae”. Its production is supposed to be low cost
and high-yielding – giving up to nearly 30 times the energy per unit area as
can be realized from current, conventional ‘first-generation’ biofuel
Below is a list of feedstock currently
under consideration or research for
potential use in biofuels.
•Certain fungi & Algae
• Three categories of properties: Nutrient requirements
• Nutrient Requirements: Sunlight
Carbon-dioxide (carbon source)
Very little fertilizer
(Fertilizer is a major limiting resource and also contributes to global warming. The
less fertilizer a feedstock uses, the more environmentally friendly it will be.)
• Water is a scarce and valued resource, so the less a particular feedstock
requires the better. Best water to fuel yield comes from algae- A litre of
fuel/3.15 litre of water (under ideal conditions).
• Yield- Yield is often measured in gallons per acre and is an important metric
for assessing feedstock. The less land a particular biofuel feedstock requires,
• Growth Conditions: This simply refers to climate. Some feedstock does okay in
the cold and others do better in tropical locations. For countries looking to use
biofuel to gain energy independence, this is very important. For instance, the
tropical plant Jatropha is not going to be of much use in the temperate climate
of Europe. Feedstock is very much specific to regions of the planet; there is no
Petroleum diesel (Petro diesel) is a product produced through the fractional
distillation of crude oil. The product contains a mixture of hydrocarbon
molecules that range in size from 8 to 21 carbon atoms. A typical Petro diesel
molecule would look something like this 16-carbon molecule.
Note that the Petro diesel molecule is a pure hydrocarbon, containing only hydrogen and carbon atoms
and no oxygen.
Compare the Petro diesel molecule above with a typical biodiesel molecule as
Biodiesel with 17 carbons (also called 16 carbons with an ester group)
In many ways, the biodiesel and Petro diesel molecules are similar. In fact, the
only real difference is on the right side of the molecule where the biodiesel
has two oxygen atoms compared to the Petro diesel molecule. These oxygen
atoms are what make all the difference in biofuels like biodiesel, when they are
Biogas refers to a mixture of different gases produced by the breakdown of
organic matter in the absence of oxygen. Biogas can be produced from raw
materials such as agricultural waste, manure, municipal waste, plant material,
sewage, green waste or food waste.
PRODUCTION OF BIO-GAS
Biogas is produced through the processing of various types of organic waste.
It is a renewable and environmentally friendly fuel made from 100% local
feedstocks that is suitable for a diversity of uses including road vehicle
fuel and industrial uses. The circular-economy impact of biogas production is
further enhanced by the organic nutrients recovered in the production
Biogas is produced using well-established
technology in a process involving several stages:
1. Biowaste is crushed into smaller pieces and
slurrified to prepare it for the anaerobic
digestion process. Slurrifying means adding liquid
to the biowaste to make it easier to process.
2. Microbes need warm conditions, so the
biowaste is heated to around 37 °C.
3. The actual biogas production takes place
through anaerobic digestion in large tanks for
about three weeks.
4.In the final stage, the gas is purified
(upgraded) by removing impurities and carbon
After this, the biogas is ready for use by
enterprises and consumers, for example in a
liquefied form or following injection into the gas
Stages in biogas production
18. BIOGAS EFFICIENCY
Biogas has a lower methane
content than natural gas and
raw biogas has to be processed
and have it's impurities
removed to make it viable.
Furthermore, the type of
feedstock can affect the
calorific value of the biogas.
For example wood would be
preferable to sewage in
producing more energy dense
◍ Mainly produced by sugar fermentation, but also
manufactured by the chemical process of reacting
◍ The main sources of sugar required to produce ethanol
come from fuel or energy crops.(corn, maize, waste straw,
wheat crops, Reed Cranary grass, sawdust, etc)
◍ There are still ongoing research for using solid waste to
produce ethanol fuel.
◍ Ethanol or ethyl alcohol (C2H5OH) is a clear colourless liquid, it
is biodegradable, low in toxicity and causes little environmental
pollution if split.
◍ It burns to give CO2 and water
◍ It is a high octane fuel and has replaced lead as an octane
enhancer in petrol.
◍ By blending ethanol with gasoline we can also oxygenate the
fuel mixture, which helps it burn completely and reduces
◍ Most common blend is 10% ethanol and 90%petrol(E10). Flexible
fuel vehicles can run on up to 85% ethanol and 15% petrol
◍ Ethanol can be produced from biomass by the hydrolysis and sugar fermentation
◍ biomass place contains a complex mixture of carbohydrate polymers from the plant
cell wall is known as cellulose hemicellulose and lignin.
◍ In order to produce sugars from the biomass, the biomass is the biomass is pre-
treated with acid or enzymes in order to reduce the size of the feedstock and to
open up the plant structure.
◍ The cellulose and the hemicellulose portions are broken down by enzymes a dilutes
acid into sucrose sugar that is done fermented into ethanol.
◍ The lignin which is also present in the biomass is normally used as a fuel for the
ethanol production plant boilers
◍ There are three principle methods for extracting sugars from biomass
Concentrated acid hydrolysis,
Dilute acid hydrolysis,
22. Concentrated acid hydrolysis
The process used is Arkanol process,by adding 70%-77%sulphuric
acid to the biomass that has been dried to a 10% moisture content.
Dilute acid is used to hydrolyse the biomass to sucrose.
The first stage uses 0.7% sulphuric acid at 190C to hydrolyse the
hemi cellulose present in the biomass.
The second stage is optimised to yield the more resistant cellulose
fraction. This is achieved by using 0.4% sulphuric acid at 215C.
The liquid hydrolates are then neutralised and recovered from the
Dilute acid hydrolysis
◍ The dilute acid hydrolysis process is one of the oldest, simplest and
most efficient methods of producing ethanol from biomass.
◍ Dilute acid is used to hydrolyze the biomass to sucrose.
◍ The first stage uses 0.7% sulphuric acid at 190⁰C to hydrolyze the
hemi cellulose present in the biomass.
◍ The second stage is optimized to yield the more resistant cellulose
fraction. This is achieved by using 0.4% sulphuric acid at 215⁰C.
◍ The liquid hydrolases are then neutralized and recovered from the
◍ Instead of using acid to hydrolyse the biomass into sucrose, we can use
enzymes to break down the biomass in a similar way. However this process
is very expensive and is still in its early stages of development.
• Corn can be processed into ethanol by either the dry milling or the wet milling
• In the wet milling process, the corn kernel is steeped in warm water, this helps
to break down the proteins and release the starch present in the corn and
helps to soften the kernel for the milling process.
• The corn is then milled to produce germ, fibre and starch products. The germ
is extracted to produce corn oil and the starch fraction undergoes
centrifugation and saccharifcation to produce gluten wet cake.
• The ethanol is then extracted by the distillation process. The wet milling
process is normally used in factories producing several hundred million gallons
of ethanol every Year.
◍ The dry milling process involves
cleaning and breaking down the
corn kernel into fine particles
using a hammer mill process.
◍ This creates a powder with a
course flour type consistency. The
powder contains the corn germ,
starch and fibre.
◍ In order to produce a sugar
solution the mixture is then
hydrolyzed or broken down into
sucrose sugars using enzymes or a
dilute acid. The mixture is then
cooled and yeast is added in order
to ferment the mixture into
◍ The dry milling process is normally
used in factories producing less
than 50 million gallons of ethanol
The hydrolysis process breaks down the cellulosic part of the biomass or corn
into sugar solutions that can then be fermented into ethanol. Yeast is added
to the solution, which is then heated. The yeast contains an enzyme called
invertase, which acts as a catalyst and helps to convert the sucrose sugars
into glucose and fructose (both C6H12O6).
The chemical reaction is shown below:
The fructose and glucose sugars then react with another enzyme called
zymase, which is also contained in the yeast to produce ethanol and carbon
The chemical reaction is shown below:
The fermentation process takes around three days to complete and is carried
out at a temperature of between 250C and 300C.
28. Fractional Distillation
The ethanol, which is produced from the fermentation process, still contains a
significant quantity of water, which must be removed. This is achieved by
using the fractional distillation process. The distillation process works by
boiling the water and ethanol mixture. Since ethanol has a lower boiling point
(78.3C) compared to that of water (100C), the ethanol turns into the vapour
state before the water and can be condensed and separated.
• Bio ethanol has a number of advantages over
conventional fuels. It comes from a renewable
resource i.e. crops and not from a finite resource and
the crops it derives from can grow well in the UK
(like cereals, sugar beet and maize).
• Another benefit over fossil fuels is the greenhouse
gas emissions. The road transport network accounts
for 22% (www.foodfen.org.uk) of all greenhouse gas
emissions and through the use of bio ethanol, some of
these emissions will be reduced as the fuel crops
absorb the CO2 they emit through growing.
• Also, blending bio ethanol with petrol will help extend
the life of the UK’s diminishing oil supplies and ensure
greater fuel security, avoiding heavy reliance on oil
producing nations. By encouraging bio ethanol's use,
the rural economy would also receive a boost from
growing the necessary crops.
• Bio ethanol is also biodegradable and far less toxic
that fossil fuels.
• In addition, by using bio ethanol in older engines can
help reduce the amount of carbon monoxide produced
by the vehicle thus improving air quality.
• Another advantage of bio ethanol is the ease with
which it can be easily integrated into the existing
road transport fuel system. In quantities up to 5%,
bio ethanol can be blended with conventional fuel
without the need of engine modifications.
• Bio ethanol is produced using familiar methods, such
as fermentation, and it can be distributed using the
same petrol forecourts and transportation systems
• Biobutanol is a four-carbon alcohol
produced by the fermentation of biomass.
It has a long hydrocarbon chain which
renders it fairly non-polar. The
production of biobutanol can be carried
out in ethanol production facilities. The
primary use of biobutanol is a fuel in an
internal combustion engine.
• Its properties are similar to that of
gasoline. Some gasoline-powered vehicles
can even use biobutanol without being
modified. It can be blended with gasoline in
concentrations up to 11.5% by volume.
However, it has a lower energy content, on
average 10-20%, than that of gasoline,
which is a major disadvantage of biobutanol.
• Biobutanol exhibits the potential to reduce
carbon emissions by 85% when compared to
gasoline, thus making it a viable and suitable
alternative to gasoline and gasoline-ethanol
◍ Biobutanol can be produced by fermentation of biomass by the A.B.E. process. The process uses
the bacterium Clostridium acetobutylicum, also known as the Weizmann organism, or Clostridium
beijerinckii. It was Chaim Weizmann who first used C. acetobutylicum for the production
of acetone from starch (with the main use of acetone being the making of Cordite) in 1916. The
butanol was a by-product of fermentation (twice as much butanol was produced). The process also
creates a recoverable amount of H2 and a number of other by-products: acetic, lactic and propionic
acids, isopropanol and ethanol.
◍ Biobutanol can also be made using Ralstonia eutropha H16. This process requires the use of an
electro-bioreactor and the input of carbon dioxide and electricity.
◍ The difference from ethanol production is primarily in the fermentation of the feedstock and
minor changes in distillation. The feedstocks are the same as for ethanol: energy crops such
as sugar beets, sugar cane, corn grain, wheat and cassava, prospective non-food energy crops such
as switchgrass and even guayule in North America, as well as agricultural byproducts such
as bagasse, straw and corn stalks. According to DuPont, existing bioethanol plants can cost-
effectively be retrofitted to biobutanol production.
◍ Additionally, butanol production from biomass and agricultural byproducts could be more efficient
(i.e. unit engine motive power delivered per unit solar energy consumed)
than ethanol or methanolproduction.
◍ Algae butanol: Biobutanol can be made entirely with solar energy and nutrients, from algae (called
Solalgal Fuel) or diatoms. Current yield is low.
37. At high concentrations, bio butanol be blended with conventional petrol rather
than ethanol for use in unmodified engines. Experiments have also proved that
bio butanol can be used in unmodified conventional engines at 100%. However,
no manufacturers have guaranteed use of blends greater than 15%.
Bio butanol has a higher energy content than ethanol. With an energy content
of about 105,000 BTUs/gallon, bio butanol is close to the energy content of
gasoline, which is roughly 114,000 BTUs/gallon.
Less corrosive and explosive than ethanol, bio butanol is also less susceptible to
separation in the presence of water than ethanol. It can be produced
domestically from a variety of feed stocks, which can also help drive the
economy via the generation of jobs.
Carbon dioxide captured by growing feedstock minimizes overall greenhouse
gas emissions by balancing carbon dioxide released from burning biobutanol.
Environmental Protection Agency (EPA) test results show that biobutanol
reduces hydrocarbon, carbon monoxide and nitrogen oxide emissions.
38. Want big impact?
Use big image.
There is now increasing interest in the use of biobutanol as a transport fuel.
Unfortunately though no production vehicle is known to be approved by manufacturers
for use with 100% butanol.
Biobutanol also shows promise as an industrial solvent and chemical feedstock. In
addition to this possible other applications may include paints/coatings, resins,
plasticizers, pharmaceuticals, food grade extractants, chemical intermediates and
39. Recent Advancements
Nowadays over 50 countries have adopted
In recent years, nanocatalyst technology has
been widely used for biodiesel production for the
development of economically sustainable biodiesel
Other areas of concern include development of
improved harvesting and dewatering technologies,
improved oil extraction and downstream
processing, and development of new/alternate
conversion methods that can yield Bio-Fuels.
New/ improved technologies must reduce
energy intensity, capital and operating
costs, and have scalability, effective
process, techno-economics and life-cycle
environmental impacts of biomass used.
Currently, major challenges in biofuel/
bioproducts conversion include poor cost
effectiveness, lack of mature
alternative conversion technologies, and
lack of substantial data needed to
evaluate life-cycle environmental
impacts of conversion technologies.
Biofuels are the solid, liquid or gas fuel derived from
biomass or Bio- wastes.
There are different types of biofuels produced by
different methods like Anaerobic digestion,
Biofuels are a solution to any issues like environment
pollution, global warming solid waste management etc.
As all other, Bio fuels also encounter quite a few
disadvantages like low efficiency, tedious process for
production, careful management, and automobiles not
designed to use up bio-fuels.
Recent advancements and studies is based on, how to
minimize the limitations of bio-fuels.