1. BIOMASS
INTRODUCTION

2. Biomass is biological material derived from living or recently
living organism
The terms biomass therefore covers arrange of organic
materials recently produced from plants and animals that feed
on the plants
Biomass can be collected and converted into useful bioenergy
It includes crop residues,forest &wood process
residues,animal wastes including human sewage,municipal
sewage waste(MSW)(excluding plastic&nonorganic),food
processing waste&short rotation crops

3. As the word clearly signifies;biomass means organic matter
and photochemical approach to harness solar energy means
harnessing of solar energy by photosynthesis.
Biomass is the plant material derived from the reaction
between Co2 in the air,water and sunlight,via
photosynthesis,to produce carbohydrates that from the
building blocks of biomass.
If biomass is processed efficiently,either chemically or
biologically,by extracting the energy stored in chemical bonds
and the subsequent ‘energy’product combined with
oxygen,the carbon is oxidised to produce Co2 and water.

4. The process is cyclical,as the Co2 is then available to produce
new biomass
Through the process of photosynthesis,chlorophyll in plants
captures the sun’s energy by converting carbon dioxide from
the air and water from the ground into carbohydrates.

5. All these biomass dispersed and bulky and contain large
amount of water(50-90%)however biomass can be converted
into liquid or gaseous fuels,thereby increasing its energy
density and making feasible transportation over long
distances.

6. Fuels are derived from biomass are easily handled and
burnt,whereas raw biomass is often wet and of inconsistent
quality or variable composition.
Biomass has a very high potential as a renewable energy
resource beacause of its reliability and availibility everywere
around the globe.
It is the fourth highest primary energy resource in the world
after oil,coal,and gas,contributing about 10.6% of the global
primary energy supply.
Biomass is the only other naturally occuring energy containing
carbon resource that is large enough in quantity to be used as
a substitute for fossile fuels.

7. BIOMASSPOTENTIALIN INDIA
India,being a trophical country,has tremendous potential for
energy generation through biomass and its residues.
Biomass energy is normally found in the form of
firewood,agricultural residues such as bagasse,crop
straw,animal dung and wastes generated from agro based
industries.

8. Biomass can be classified into two types:
Woody and non-woody.
Non-woody biomass comprises agro-crop and agro-industrial
processing residue.
Municipal solid wastes,animal and poultry wastes are also
referred to as biomass as they are biodegradable in nature.
The main biomass sources as listed below:

9. 1)Wood and wood waste:
forest wood,wood from energy
plantations,saw dust,tree branches
and leaves etc.
2)Agricultural residues:
rise husk,bagasse,grondnut
shells,coffee husk,straws,coconut
husk,jute sticks etc.
3)Aquatic and marine biomass:
Algae,aquatic weeds and plants,sea
grass beds,etc.

10. 4)Wastes:
Municipal solid waste,municipal sewage sludge,animal
waste,paper waste,industrial waste etc.

11. BIOMASS TYPES
The various types of biomass in different ways but one simple
method is to define four main types,namely;
 Woody plants
 Herbaceous plants/grasses
 Aquatic plants
 Manures

12. Aquatic plants and manures are intrinsically high moisture
materials and as such,are more suited to ‘wet’processing
techniques.
High moisture content biomass,such as herbaceous plant
sugarcane,lends itself to a ‘wet/aqueous’conversion process
,involving biologically mediated reactions,such as
fermentation.
While a ‘dry’biomass such as wood chips,is more economically
suited to gasification,pyrolysis or combustion.

13. PLANT CHARACTERISTICS
Biomass contains varying amounts
of cellulose,hemicellulose,lignin
and a small amount of other
extractives.
Cellulose is a glucose
polymer,consisting of linear chains
of(1-4)-D-glucopyranose units,in
which the units are linked 1-4 in
the beta-configuration,with an
average molecular weight of
around 100,000

14. Hemicellulose is a mixture of
polysaccharides,composed almost
entirely of sugars such as
glucose,manose,xylose with an
average molecular weight
of<30,000.
Lignin can be regarded as a group
of amorphous,high molecular
weight,chemically related
compounds.

15. Cellulose is generally the largest fraction,representing about
40-50%of the biomass by weight;the hemicellulose portion
represents 20-40%of the material by weight.

16. BIOMASS PROPERTIES
It is the inherent properties of the biomass source that
determines both the choice of conversion process and any
subsequent difficulties that may arise.
The main material properties of interst,during subsequent
processing as an energy source,relate to:

17. o Moisture content(intrinsic&extrinsic)
o Calorific value,
o Proportions of fixed carbon and volatiles
o Ash/residue content
o Alkali metal content
o Cellulose/lignin ratio
For dry mass conversion processes,the first five properties are
of interst,while for wet biomass conversion processes,the first
and last properties are of prime concern

18. MOISTURE CONTENT
Two forms of moisture content are of interst in biomass:
1)Intrinsic moisture: the moisture content of the material
without the influence of weather effects.
2)Extrinsic moisture: the influence of prevailing weather
conditions during harvesting on the overall biomass moisture
content.

19. BIOMASS CONVERSION
TECHNOLOGIES
Biomass conversion can take many forms:
1)Direct combustion
2)Thermochemical conversion
3)Biochemical conversion

20. DIRECT COMBUSTION
This is perhaps the simplest method energy from biomass.
Industrial biomass combustion facilitates can burn many types
of biomass fuel,including wood,agricultural residue,wood
pulping liquor,municipal solid waste and refuse-derived fuel.

21. THERMOCHEMICAL
CONVERSION
It takes place two forms:gasification and
liquefaction.
Gasification takes place by heating the biomass with
the limited oxygen to produce low heating value gas
or by reacting it with steam and oxygen at high
pressure and temperature to produce medium
heating value gas.

22. BIOCHEMICAL
CONVERSION
It takes place two forms.
Anaerobic digestion and Fermentation
Anaerobic digestion: it involves the microbial digestion of
biomass.
An aerobe is a micro-organism that can live and grow without
air or oxygen,it gets its oxygen by the decomposition of matter
containing it.
The process takes place at low temperature upto 65 degree
celcius,and requires a moisture content of atleast 80%.
It generates a gas consisting mostly of co2 and methane with
minimum impurities such as hydrogen sulfide.

23. FERMENTATION
It is the breakdown of complex molecules in organic
compound under the influence of a ferment such as
yeast,bacteria,enzymes,etc.
Fermentation is well-established and widely used technology
for the conversion of grains sugar crops into ethanol.

24. WET PROCESSES
Anaerobic digestion: biogas is
produced by the bacterial
decomposition of wet sewage
sludge,animal dung or green
plants in the absense of
oxygen.
Feedstockes like –wood
shavings,straw and refuse
may be used,but digestion
takes place much longer.

25. The natural decay process,can be speeded by using a
thermally insulated ,air-tight tank with a stirrer unit and
heating system.
At optimum temperature(35degree celcius)complete
decomposition of animal or human faces takes around 10days.

26. Fermentation : as
stated,ethanol(ethyl alcohol) is
produced by the fermentation
of sugar solution by natural
yiests.
After about 30 hrs of
fermentation the
brew(/beer)contains6-10%
alcohol and this can readily be
removed by distillation.

27. DRY
PROCESSES
Pyrolysis: in its simplest
form ,pyrolysis representsheating
the biomass to drive off the volatile
matter and leaving behind the
charcoal.
Pyrolyis also converts biomass into
phenol oil,a chemical used to make
wood adhesives,molded
plastics,amd foam insulation.

28. Liquefaction: liquids yields are maximised by
rapid heating of the feedstockto
comparativelylow temperatures.
 the vapours are condensed from the gas stream
and these separate into two-phase liquor: the
aqueos phase contains a soup of water soluble
organic materials like acetic acid,acetone and
methanol.
The non-aqueos phase consists of oils and tars.

29. Gasification: it is a process
that exposes a solid fuel to high
temperatures and limited oxygen,to
produce a gaseous fuel.
The advantage of gasification is that it
produces a fuel that has had many
impurities removed and could
therefore cause fewer pollution
problems when burnt.

30. Photosynthesis : photosynthesis in the plants is an
example of biological conversion of solar energy
into sugars and starches which are energy rich
compounds.

31. The process of photosynthesis hastwo main steps:
1)Splitting of water molecule into H2 &O2 under the influence
of chlorophyll and sunlight.this phase of reaction is called the,
Light reaction.in this phase of reaction ,light absorbed by
chlorophyll causes photolysis of water.O2 escapes and H2 is
transformed into some unknown compounds.thus solar energy
is converted into potentil chemical energy.
2)In the second phase,hydrogen is transformed from this
unknown compound to CO2 to form starch or sugar.formation of
starch or sugar are Dark reaction not requiring sunlight

32. BENEFITS OF BIOMASS ENERGY
Biomass energy is an abudant,secure,environmental friendly
and renewable sorce of energy.Biomass doesn’t add carbon
dioxide to the atmosphere as it absorbs the same amount of
carbon in growing as it releases when consumed as a fuel.
One of the major advantages of biomass is in the same power
plants that are now burning fossil fuels.
Biomass energy isn’t associated with environmental impacts
suchas acid rain,mine spoils,open pits,oil spillls,radioactive
waste disposal or the damaging rivers.
Biomass fuels are sustainable.The green plants from which
biofuels are derived fix carbon dioxide as they grow,so their
use doesn’t add to the levels of atmospheric carbon.

33. Alcohols and other fuels produced by biomass are
efficient,viable,and relatively clean burning.
Biomass is easily available can be grown with relative ease in
all parts of the world.

34. CONSTRAINSTOBIOMASSENERGYUSE
Biomass is still an expensive source of energy,both in terms of
producing biomass and converting it into alcohols,as a very
large quantity of biomass is needed.
On a small scale there is most likely a net loss of energy as a
lot of energy must be used for growing the plant
mass;biomass is difficult to store in the raw form.
One of the disadvantages of biomass can be harmful is that
combustion of biomass can be harmful to the environment as
burning biomass releases Co2,which contributes to the
warming of the atmosphere ans possible climate change .
Over-collecting wood can destroy forests.
Biomass has less energy than a similar volume of fossil.