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1. 20PH2E02 NON-CONVENTIONAL ENERGY RESOURCES 3 0 0 3
Ms.D.Sudha
Assistant Professor
Dept. of Physics
04/22/2025 1
SRI RAMAKRISHNA ENGINEERING COLLEGE
[Educational Servic: SNR Sons Charitable Trust]
[Autonomous Institution, Reaccredited by NAAC with ‘A+’ Grade]
[Approved by AICTE and Permanently Affiliated to Anna University, Chennai]
[ISO 9001-2015 Certified and All Eligible Programmes Accredited by NBA]
VATTAMALAIPALAYAM, N.G.G.O. COLONY POST, COIMBATORE – 641 022.
DEPARTMENT OF PHYSICS
Biomass Energy

2. Biomass Energy
04/22/2025 2
• Bioenergy is renewable energy made available from
materials derived from biological sources.
• Biomass is any organic material, may include
wood, wood waste, straw, manure, sugar cane and
many other byproducts from a variety of
agricultural processes.
Bio-Energy

3. Biomass Energy
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Biomass
Biomass is organic matter produced by plants –
terrestrial and aquatic – and their derivatives. It includes
1. Forest crops and residues
2. Crops specially grown in ‘energy farms’ for their
energy content
3. Animal manure

4. Biomass Energy
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Biomass
Energy
Biomass continues to account for an estimated 1/3rd
of
primary energy use, while in the poorest counties up to
90% of all energy is supplied by biomass.
Biomass energy, or bio energy is the conversion of
biomass (organic material originating from plants, trees,
and crops and essentially the collection and storage of
the sun’s energy through photosynthesis) into useful
forms of energy such as heat, electricity, and liquid fuels.

5. Biomass Energy
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Biomass Energy Conversion Technologies
Biomass energy conversion technologies/applications
include:
• Combustion
• Gasification
• Anaerobic Digestion
• Liquid Biofuels

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Primary energy conversion technologies
• Combustion - direct combustion of biomass is the most
common way of converting biomass to energy - both
heat and electricity. Compared to the gasification and
pyrolysis it is the simplest and most developed.
• Gasification - gasification is a high-temperature (1200-1400
o
C) thermo chemical conversion process but the process is
used for production of gas, instead of heat.
• Pyrolysis - thermal decomposition occurring in the absence
of oxygen. We use pyrolysis to produce a liquid fuel, bio-oil
or pyrolysis oil.

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1. Biogas
• Getting energy out of biomass by burning it, turning
it into a liquid or by turning it into a gas called bio
gas.
• It contains about 65% of methane gas as a major
constituents.

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2. Bio-fuel
• Bio-fuel (also called agro fuel) is a bioorganic fuel.
It is obtained by the fermentation of biomass
• The process by which micro-organisms break down
complex organic substances
• Generally in the absence of oxygen to produce
alcohol and carbon dioxide is called Fermentation.

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Examples of Biofuel
Ethanol:
It is produced from sugarcane. Its calorific value is
less than petrol. It also less heat when compare to petrol.
Methanol:
It is easily obtained from ethanol. Its calorific value is
too low when compared to gasoline and diesel.
Gasohol:
It is a mixture of ethanol + gasoline. It is used in
cars and buses.

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Significance of Bio-energy
Cost is low when
compare to fossil fuels
Biomass consumes more
CO2 than is released
during combustion of
biomass.

11. Biomass Energy
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Biofuel Fossil
fuel
Bio-fuel is produced directly from
plant matter typically corn, sugar
cane, sugar beets, or cellulose
transforming it into alcohol.
Fossil fuels are produced by either
the decomposition of plant or
animal matter over long periods of
time under certain conditions such
as high temperature and pressure.
Fossil fuels are coal, oil, and
natural gas.
Differences

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Plant operation
• Biomass is organic compounds produced in
natural processes.
• These compounds are transported to the biomass
plant and burned to heat water.
• Steam is produced at high pressure and it moves a
turbine and this moves the generator to produce
electricity.

13. Biomass Energy
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ADVANTAGES
• It’s a renewable source of energy.
• It’s a comparatively lesser pollution generating energy.
Biomass energy helps in cleanliness in villages and
cities. There is tremendous potential to generate
biogas energy. Biomass energy is relatively cheaper
and reliable.
• It can be generated from every day human and
animal wastes, vegetable and agriculture left-over
etc.
• Growing biomass crops use up carbon dioxide
and produces oxygen.

14. Introduction to Biomass
India is a land of village where the
energy required for domestic
purpose such as cooking is met
from dried woods, twigs and leaves
of plants and other dried organic
matter such as cow dung.
This organic matter called as
biomass is available freely as
waste.
It contains stored energy from the
sun.

15. Introduction to Biomass
It is a renewable energy
source because we can
always grow more trees
and crops, and waste
will always exist.
The biomass is fast
renewable forms of
available
energy and
freely as
waste
and
discarded matters.

17. Photosynthesis Process
Photosynthesis is a
process
converts
chemical
that
carbon
dioxide into organic
compounds,
especially
using
the
sugars,
energ
y
from sunlight.

18. Photosynthesis Process

19. Photosynthesis Process
Biomass is produced in the photosynthesis process
which converts the solar energy into biomass energy.
Photosynthesis process only occurs in green plants. It
is the process of combining the carbon dioxide from
the atmosphere with water plus light energy to
produce carbohydrates (sugars, starches, celluloses
etc.) and oxygen.
Photosynthesis
6CO2 + 6H2O + light energy C6H12O6 + 6O2

20. Splitting of water molecule into H2 & O2 under influence of chlorophyl.
“Light Reaction”
Hydrogen is transferred to CO2 to form Starch or Sugar.
Light
CO2 Concentration
Temperature

21. Biomass energy conversion
The various process used
for coversion of biomass
into energy or bio fuels
can be classified as
follows:
1) Direct combustion
2) Thermo chemical
conversion
3)Biochemical
conversion

23. Direct Combustion
The direct combustion of biomass in presence of oxygen/air to
produce heat and by products is called direct combustion.
The complete combustion of biomass into ash is called
incineration.
This heat energy in the product gases or in the form of steam
can be used for various applications like space heating or
cooling, power generation, process heating in industries or any
other application.
However, if biomass energy by combustion is used as co-
generation with conventional fuels, the utilization of biomass
energy makes it an attractive proposition.

24. Direct Combustion/Steam Turbine
System
Biomass

25. THERMO CHEMICAL
CONVERSION
The thermo chemical reaction can convert the
organic biomass into more valuable and
convenient form of products as gaseous and
liquid fuels,residue and by-products etc.
These processes can be carried out in following
ways:
1) Gasification
2) Pyrolysis

26. THERMO CHEMICAL CONVERSION

27. Gasification
• Heating of biomass in presence of limited
oxygen and air (deficient O2/air) is called
Gasification. It produces gaseous fuels like H2,
CO, CH4, N2 of low calorific value.

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Gasification

29. Pyrolysis
It is the heating of biomass in a closed vessel at
tempratures in the range 500 oC - 900 oC in absence of
O2/air or with steam. It produces solid,liquid and gases.
The pyrolysis process can use all type of organic
materials including plastic and rubbers.

30. Biochemical Conversion
In biochemical processes the bacteria and micro
organisms are used to transform the raw biomass
into useful energy like methane and ethane gas.
Following organic treatments are given to the
biomass:
1) Fermentation of biomass (Aerobic digestion)
2) Anaerobic digestion of biomass

31. Fermentation
Fermentation is a process of decomposition of complex
molecules of organic compound under the influence of
micro-organism (ferment) such as yeast, bacteria,
enzymes etc.
The example of fermentation process is the conversion
of grains and sugar crops into ethanol and CO2 in
presence of yeast.

32. Anaerobic digestion
The anaerobic digestion or
anaerobic fermentation
process involves
the
conversion of
decaying
wet
biomass and animal waste into
biogas through decomposition
process by the action of
anaerobic bacteria.
The most useful biomass for
production of biogas are
animal and human waste,
plant residue and other
organic waste material with
high moisture content.

33. Biogas Generation
Biogas contains 55-65% methane, 30-40% CO2, and the
remainders are impurities like H2S, H2, N2 gases.
Cattle dung can produce 0.037 m3 of biogas per kg of
cow dung. The calorific value of gas is 21000 to 23000
kJ/kg or about 38000 kJ/m3 of gas. The material from
which biogas is produced retains its value as fertilizer
or as animal feed which can be used after certain
processing.

34. Biogas Generation
Biogas can be produced by digestion pyrolysis or hydro
gasification. Digestion is a biological process that occurs
in absence of O2 and in presence of anaerobic organisms
at atmospheric pressure and temperatures of 35oC-70oC.
The container in which the digestion takes place is called
digester.
When organic matter undergoes fermentation, the
anaerobic bacteria extracts oxygen by decomposing the
biomass at low temperatures up to 65oC in the presence of
moisture. (80-95%), the gas so produced is called biogas.

35. Principle of biogas production
Biogas production takes place in three stages:
1) Hydrolysis: In this stage, matters with heavy
molecular weight are disintegrated into lower
molecular weight. This process takes place by
hydrolytic bacteria.
2) Acid Formation: In this stage, organic matters are
converted into acetates and H2. This conversion takes
place by acetogenes. Then H2 and C are converted
into acetate by acetogenes.

36. Principle of biogas production
3) Methane Gas Formation: In this stage, acetates
and simple CO2 are converted into CH4. This is
carried out by methanogenes.

37. Factors affecting biogas production
The rate of production of biogas depends on the
following factors:
1) Temperature & Pressure
2) Solid concentration & Loading rate
3) Retention period
4) pH value
5) Nutrients composition
6) Toxic substances
7) Digester size & shape
8) Stirring agitation of the content of digestion

38. BioMass Energy
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What is Bio Gas
• Biogas is an alternative and renewable energy
that can be produced by the anaerobic (absence
of oxygen) decomposition of organic matter.
• Biogas can be produced from regionally
available raw materials such as recycled waste
and is a renewable energy source
• Typically, using organic wastes as the major
input, the systems produce biogas that contains
55% to 70% CH4 and 30% to 45% CO2.

39. BioMass Energy
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What is Bio Gas ?
• Biogas is produced by anaerobic digestion with
anaerobic bacteria orfermentation of biodegradable
materials such as manure, sewage, municipal waste,
green waste, plant material, and crops.
• The gases methane, hydrogen, and carbon monoxide
(CO) can be combusted or oxidized with oxygen.
• Landfill gas is produced by wet organic waste
decomposing under anaerobic conditions in a landfill

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Elements of Anaerobic Digestion Systems
Manure collection and handling
Pre- Treatment
Anaerobic digestion
By-Product recovery and effluent use
Biogas Recovery Biogas Handling and use

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How Anerobic Degestion Work

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43. BioMass Energy
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Design of a Digester

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How Digester Works
• Temperature must be kept between 65 degrees
and 150 degrees
• 4 Types of bacteria breakdown the waste
– Hydrolytic breaks organic material to simple
sugar and amino acids
– Fermentative then converts to organic
acids
– Acidogenic convert to carbon dioxide, acetate,
and hydrogen
– Methanogenic produces biogas

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Methanogenesis
CO2 + 4 H2 → CH4 + 2H2O
CH3COOH → CH4 + CO2
Chemistry Overall Reaction
C6H12O6 → 3CO2 + 3CH4

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Hydrolysis:
• This is the first step where particulate materials get
converted to soluble compounds suitable for further
breakdown in the next step.
Acidogenesis:
• The second step of degradation is known as
fermentation or acidogenesis where the products of
hydrolysis such as simple sugars, amino acids, fatty
acids etc. break down further and produce final
products of fermentation such as H2, CO2 and
acetate.

47. BioMass Energy
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Combined Heat and Power
• Also known as cogeneration
• Using the heated water for other purposes such as
heating buildings or creating additional energy

48. BioMass Energy
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Biogas Digester System Concerns
• Releases Nitrogen and ammonia into the
atmosphere both of which hazardous
• Can release Hydrogen Sulfide a very toxic gas
• Methane released can create explosive
atmosphere
• Should raw materials get into water supply
can contaminate the water
• Transportation is of a concern because methane is
explosive although new technology may allow it to be
stored in powder form

49. Classification of Biogas Plants:
Biogas plants are mainly classified as:
1. Continuous and batch type (as per the
process)
a) Single stage process
b) Double stage process
2. The dome and drum type
3. Different variation in the drum type

50. Schematic diagram of Single stage and
Double stage Continuous Plant:

51. Contd…
The main features of continuous plant are
as follows:
1.It will produce gas continuously.
2.It require small digestion chambers.
3.It needs smaller period of
digestion.
4.It has less problem compared to batch type and
it is easier in operation.

52. Continued…
The main features of Batch type plant are:
1. The gas production is intermittent, depending upon
the clearing of the digester.
2. It needs several digesters or chambers for
continuous gas production, these are fed alternately.
3. Batch plants are good for long fibrous materials.
4. This plant needs addition of fermented slurry to
start the digestion process.
5. This plant is expensive and has problems
comparatively, the continuous plant will have less
problems and will be easy for operation.

53. The Dome and the Drum Type
Mainly two types of biogas plants are normally used:
1.The floating gas holder plant (Also known as KVIC plant)
2.Fixed dome digester (Also known as Chinese Plant)
In a floating gas holder, gas holder is separated from the digester.
While in fixed dome digester, the gas holder and the digester are
combined.
The fixed dome is best suited for batch process especially when
daily feeding is adopted in small quantities.
The fixed dome type plant is generally built below the ground
level and is suitable for cooler regions.

54. Floating Drum plants

55. Contd…

56. Contd…

57. Contd…
Floating-drum plants consist of a digester and
a moving gasholder.
The gasholder floats either direct on
the fermentation slurry or in a water jacket of its
own.
The gas collects in the gas drum, which
thereby rises.
If gas is drawn off, it falls again. The gas drum
is prevented from tilting by a guide frame.

58. Advantages
High gas yield.
No problem of gas leakage.
Works under constant pressure naturally.
No problem of mixing of biogas with
external air, thus no danger of explosion.

59. Disadvantages
It has higher cost.
Heat is lost through metal gas holder.
Requires painting of drums to avoid corrosion at
least twice a year.
Requires maintenance of pipes and joints.

60. Fixed-Dome Type

61. Contd...

62. Contd…
A fixed-dome plant consists of an enclosed digester
with a fixed, non-movable gas space. The gas is
stored in the upper part of the digester.
When gas production commences, the slurry is
displaced into the compensating tank.
Gas pressure increases with the volume of gas
stored; therefore the volume of the digester should
not exceed 20 m³. If there is little gas in the holder,
the gas pressure is low.

63. Advantages
• Cost of plant is less compare to floating drum type
plant.
• Loss of heat is negligible since these are constructed
underground.
• No corrosion problems as in fixed dome type.
• It is maintenance free.
Disadvantages
• Needs skilled labour to operate.
• Gas production per m3 of digester volume is less.
Gas is produced at variable pressure.

64. Different variations in the drum type
There are mainly two variation in floating type plant. One
with water seal and other without water seal.
Water sealing makes the plant completely anaerobic.
Cylindrical shape of the digester is preferred because
cylinder has no corners and so that there will be no
chances of cracks due to faulty construction. This shape
also needs smaller surface area per unit volume, which
reduces heat losses also.
Moreover the scum formation may be reduced by rotating
gas holder in the cylindrical digester.

65. Advantages of biogas
• Cost of equipments used for making biogas is less and
equipments used are very simple.
• Biogas can be used for lighting, running the
engines, farm’s machine and cooking gas in the
kitchen.
• Biogas is the best medium for cooking food.
• Organic feed stocks used in the plants are
easily available at all places. Biogas plant
gives efficiency as much as 60%.
• Distribution of gas has no problems of any
gas leakage and fire.
• Waste product obtained from digester is best quality
of fertilizer and gives best yields.

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• Economic development opportunities in rural areas
• Indigenous source
• The pollutant emissions from combustion of biomass
are usually lower than those from fossil fuels
• Commercial use of biomass
• Improve fertility of soil

67. Advantages of biomass
Biomass is perennial source of renewable energy and it can
be repeatedly grown and obtained as biomass.
Biomass is non pollutant of atmosphere.
Production of biomass not only gives fuels but it also gives
good quality organic manures which when used in farms
give bumper crops.
Methane gas produced from biomass is used as domestic
fuel in gas stoves.
Biomass is available everywhere and no needs of any
transportations.

68. Advantages of biomass
• Methane gas can be used to run engines and
generator and electricity can generate.
• The biomass can be grown in near by seas and lakes.
The lands can be spread for food crops.
• I.C. Engines can be run on biogas produced from
biomass.
• Biomass can be used for plastics and pharmaceutical
products.
• Use of biomass keeps surroundings clean and
healthy without insects and pests.

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Environmental Advantages
• Renewable resource
• Reduces landfills
• Protects clean water supplies
• Reduces acid rain and smog
• Reduces greenhouse gases
• Carbon dioxide
• Methane

70. Disadvantages of biogas
• Biogas produced from biogas plant has to be used
at near by places only. It can’t be transported
over long distances.
• Biogas can’t be filled in the bottles. Biogas plant
requires more area.
• It can be established in urban area where
availability of land is limited.

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Disadvantages of Biomass Energy
• It is dispersed and land intensive as a source
• It is often of low energy density
• It is labour intensive and the cost of collecting large
quantities for commercial application is significant

72. Application of biogas
• Biogas is used as cooking fuel.
• Biogas is mental light gas burner for lighting
purpose. Biogas is used for water heating.
• It is used as fuel in I.C. Engine.
• It is used as fuel to run agricultural machineries.
• It is used to run diesel engine generator set to
produce electricity.

73. Application of biogas
• Heat of biogas is utilized in the dryer for drying
the agricultural products.
• Heat of biogas is used to heat ammonia of
refrigerating plant.
• It is used for running pumps for irrigation
purpose.
• Methane and carbon dioxide are used as raw
chemical feed stock to manufacture various
chemicals.
04/22/2025

74. Biomass Energy
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Applications
• Anaerobic digestion is used for effluent and sewage treatment.
Anaerobic digestion is a simple process that can greatly reduce the
amount of organic matter which might otherwise be destined to be
landfilled or burnt in an incinerator.
• Almost any organic material can be processed with anaerobic
digestion. This includes biodegradable waste materials such as
waste paper, grass clippings, leftover food, sewage and animal
waste.
• Anaerobic digesters can also be fed with specially grown energy
crops such as silage for dedicated biogas production.

75. Biomass Energy
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Fuel Properties of Biogas
Calorific Value
60% Methane : 22.350 to 24.22 MJ/m3. Without
CO2 : 33.525 to 35.390 MJ/m3. Octane rating
without CO2 : 130 Octane rating with CO2 : 110
Ignition temperature : 6500 C Air to methane
ratio for complete
Combustion (by volume) : 10 to 1
Explosive limits to air (by volume) : 5 to 15

76. Site selection
Following factors must be considered while selecting the site for
a biogas plant:
1.Distance
2.Minimum gradient
3.Open space
4.Water table
5.Seasonal run off
6.Distance from wells
7.Space requirements
8.Availability of
water

77. Prospects of biomass in India

78. Prospects of biomass in India

80. Disadvantages of biomass
Biomass contains 50-90% water and it is heavy.
Hence transportation if needed is very difficult.
Direct combustion of biomass produces smokes
and smells.
Calorific value of biomass if burnt in the raw form is very
less.
Biogas plants need lots of care and maintenance for
its successful operations.
It is economical if raw biomass such as cow dung is not
freely available.

81. Disadvantages of biomass
Biomass conversion plants such as biogas are
necessary to convert raw biomass into useful energy
forms.
Biogas plants occupy larges land areas.
If the biomass is required to be transported over
long distances, the cost transportaion is very high.
Biogas plants can’t be used in urban areas where the
space availability is limited.

82. Application of biomass
Waste organic biomass can be
directly used as domestic fuels.
Biogas is used as domestic
fuels in gas stoves like LPG.
Biogas can be used to run the
engines, boilers and turbines.
Methane gas produced from
biogas plants can be used to
run the gas engines and farm
machineries.
It is used for heating the water.

83. Historical Era &Future
• The adoption of biomass-based energy plants
has been a slow but steady process.
• Over the past decade, the production of these
plants has increased 14%.
• In the United States, alternative electricity-
production sources on the whole generate
about 13% of power; of this fraction, biomass
contributes approximately 11% of the
alternative production.

84. Historical Era &Future
• Energy Information Administration projected
that by 2017, biomass is expensive as twice as
natural gas, slightly more expensive than nuclear
power, and much less expensive than solar
panels.
• In another EIA study released, 598 million tons
of biomass would be available in 2025,
accounting for 12% of the renewable energy.

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Deenabandhu Biogas Project Model

86. Biomass Energy
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Present State of Biomass Energy in India
• 3,500 MW of power generation through biogases based
co-generation in sugar mills.
• 537 MW has so far been commissioned
• 536 MW is under installation

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Typical composition of biogas
Matter %
Methane, CH4 50-75
Carbon dioxide, CO2 25-50
Nitrogen, N2 0-10
Hydrogen, H2 0-1
Hydrogen sulfide, H2S 0-3
Oxygen, O2 0-2

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MUNICIPAL SOLID WASTE (MSW) TO ENERGY INCINERATION PLANT
SHREDDER
AIR
CLASSIFIER
Dry duly treated biomass
HRSG
BOILER
FURNACE
Stack
Heat Recovery Steam Generator
HRSG
Removal of pollutants
Superheated
output
Boiler
Feed
water
Cooling
Tower
Pre-heated
Feed
water
Refuse derived
fuel
Aux fuel
Metal Glass
Recycled
Thermal Output
Electrical
Output
Ash to landfill
Condenser
Pre-heated
air

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9. The production of bio ethanol is by fermenting the _________
and starch components.
a) Acid
b) Milk
c) Sugar
d) Alcohol

91. Biomass Energy
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