Sources of biofuels

Bioenergy-sources-properties-characterization-briquetting

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BIOENERGY
1. Biomass: sources, characteristics & preparation:
· Sources and classification of biomass available for energy
production.
· Chemical composition and properties of biomass
· Energy plantations
· Preparation of biomass for fuel applications: Size
reduction, Briquetting of loose biomass, Drying, and
Storage and handling of biomass.
Reference book:
Renewable Energy Engineering and Technology: Principles &
Practice, Edited by V. V. N. Kishore, 2009 T E R I, N. Delhi.
Chapters12 to 15, pp 625 to 917.
SOURCES:
The material of plants and animals is called biomass.
Bio-energy is energy derived from biomass. Before the
development of technology based on coal, lignite, crude oil
and natural gas (fossil fuels) bio-fuels were the sources of
heat energy.
Woody biomass is product of forestry and trees from
different agro-forestry activities of smaller intensity. Timber
(used for commercial purpose) and fuel wood are obtained
from the forests besides minor forest produce. Commercial
plantations like rubber and plants/trees that yield
hydrocarbon can be a source of byproduct fuel.

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Agriculture yields by annual harvest a large crop residue
biomass part of which can be a source of rural biofuels.
Plants that grow in wastelands are also potential energy
crops. Nonedible oils from trees are a byproduct liquid fuel.
Non -edible vegetable oils can be used as liquid fuels. By
trans-esterification reaction between the oil and an alcohol in
presence of an alkaline catalyst, esters can be produced that
are potential substitute for diesel as engine fuel.

Biomass that is used for producing bio-fuel may be
divided into woody, non-woody and wet organic waste
categories. The sources of each are indicated below.

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Animal manures and wastewaters containing organic
putrefiable matter can be treated by anaerobic digestion or
biomethanation to produce biogas as a fuel. Starchy and
sugar wastewaters can be substrates for fermentation
processes that yield ethanol which is a potential liquid fuel.

Sources of three categories of biomass
WOODY NON-WOODY
(cultivated)
WET ORGANIC
WASTE
FORESTS FOOD CROPS ANIMAL WASTES
WOODLANDS CROP RESIDUES MANURE, SLUDGE
PLANTATIONS
(MULTI-
PURPOSE
TREES)
PROCESSING
RESIDUES
MUNICIPAL SOLID
WASTE
HYDROCARBON
PLANTS
NONEDIBLE OIL
SEEDS
WASTE STARCH &
SUGAR
SOLUTIONS
TREES FROM
VILLAGE
COMMON
LANDS
ENERGY CROPS:
(SUGAR CANE
BAMBOO)
OTHER
INDUSTRIAL
EFFLUENTS

(B O D)

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BIOMASS CONVERSION METHODS FOR PRODUCING
HEAT OR FUELS:
Controlled decomposition of low value biomass to derive its
energy content in a useful form is the purpose of the bio-
energy programs. Biomass energy conversion may give a
mixture of bio-fuel and. by product. Examples are given
below. Bio-fuels derived from biomass can be solid, liquid
and gas fuels that can be used for combustion in specially
designed furnace, kiln and burners.

PRIMARY
BIOMASS

SECONDARY
PRODUCT
CO-
PRODUCT

WOOD

CHAR (PYROLYSIS)

PYROLYSIS
OIL

WOOD

CHAR
(GASIFICATION)

PRODUCER
GAS

ANIMAL
MANURE

BIOGAS (AN.
DIGESTION)

FERTILIZER

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Bio-fuel production from primary biomass may utilize thermo-
chemical, biochemical and catalytic conversion processes
(see following table) Conversion process chosen depends
on the properties of the primary biomass available.



THERMOCHEMICAL

BIOCHEMICAL

CATALYTIC
CONVERSION

PYROLYSIS

ANAEROBIC
DIGESTION

HYDROGENATION

GASIFICATION

FERMENTATION

TRANS-
ESTERIFICATION

COMBUSTION

HYDROLYTIC
ENZYMES

SYN.GAS
PROCESS

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Forest resources of India:

India’s is sustaining 16 % of the world’s population and
15 % of its livestock population on 2.47 % of world’s
geographical area and has just 1 % of world’s
forests.
o Forest area cover (i.e., the area notified as forest) in
1997: 76.52 million hectares, which is 23.28 % of the
total geographical area of India.
o The aggregate demand for fuelwood for the country in
1996 was 201 million tonnes, i.e., 213.8 kg per capita
per year for a population of 940 million. The current
sustainable production of fuelwood from forests is 17
million tonnes and from farm forestry and other areas is
98 million tonnes. There is a deficit of 86 million tonnes
of fuelwood, which is being removed from the forests as
a compulsion.
o Forest resource base has tremendous pressure on it
and availability is not catching up with demand for
firewood. World Environment Day: June 5
o State Forest Departments and Community based
organizations have Joint Forest Management Programs
to prevent degradation and to regenerate forest areas.

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Distribution of forest areas in States:
o In Andaman & Nicobar area, forests occupy 86.9% of
the total geographical area, whereas in Haryana,
forests occupy 3.8%.
o Arunachal Pradesh, Himachal Pradesh, Manipur,
Mizoram, Nagaland and Tripura have over 50% of their
land areas under forests while Gujarat, Jammu &
Kashmir, Punjab & Rajasthan have less than 10%. The
forest in other states range between 10 and 50 % of
their land areas and the per capita forest area of India
is 0.07 hectares.
Causes of deforestation:
o Exponential rise in human and livestock population puts
increasing demand on land allocation to alternative
uses such as agriculture, pastures, human settlements
and development activities.
o Insufficient availability of commercial fuels in rural areas
as well as the lack of purchasing power of the rural poor
and urban slum dwellers makes them dependent on
firewood and wood char as fuels for cooking.
Energy Crisis of Rural and Urban poor in India:
o Nearly 75% of the rural population of India is dependent
on bio-fuels (firewood, agricultural residues, and cow

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dung) for meeting 80% of their energy needs. Similarly
the urban poor, including the slum dwellers who
constitute 25 – 30% of the urban population are heavily
dependent on bio-fuels. This is because of their low
purchasing power and limited availability of the
commercial fuels-kerosene and LPG.
Consequences of inefficient and high consumption of
wood biomass for energy:
o Destroying biomass resources at a rate faster than that
of their regeneration may lead to depletion of forests
and desertification.
o Forests, which are earth’s largest depository (sink) of
carbon dioxide, diminish the green house effect.
Growing gap between biomass consumption and
regeneration leads to a crisis of sustainability.
WOODY BIOMASS USE SHOULD BE A BALANCED & EFFICIENT
ONE

o TECHNOLOGICAL INNOVATION ON BIOMASS
MUST CONCENTRATE ON: IMPROVING ITS
PRODUCTION, TRANSFORMATION AND
APPLICATIONS FOR ENERGY.
· WOOD BIOMASS IS AN ENDANGERED LIFE
SUPPORT SYSTEM.

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· IT SHOULD BE UTILISED IN A SUSTAINABLE
WAY.
TREES / WOOD:
Leucaena leucocephala (Subabul)
Acacia sp
Casurina sp
Derris indica (Pongam)
Eucalyptus sp
Sesbania sp
Prosopis juliflora
Azadiracta indica (Neem)

HYDROCARBON PLANTS : Euphorbia group
Euphorbia Lathyrus

OIL PRODUCING SHRUBS :
Euphorbia Tirucali
Soyabean
Sunflower
Groundnut

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Environmental impact of biomass utilization for energy:
In developing countries, trees are often cut down because
they are the only source of fuel for the population. This can
lead to environmental damage. The habitats of wild animals
are destroyed. Soil is eroded because tree roots are no
longer present to bind it together. This soil may be washed
down into rivers, which then silt up and flood. But the
destruction of trees and forests is a worldwide environmental
problem with deforestation accounting for 18% of the
greenhouse effect today. New trees must
replace the ones that are cut down if we are to protect the
global climate and the lives of people in the developing
countries.
Reference: Forests as biomass energy resources in India by
B. N. Dwivedi and O. N. Kaul in Biomass Energy Systems,
Edited by P.Venkata Ramana and S. N. Srinivas,
British Council and T E R I, N. Delhi, 1996.
Energy Plantation:
Growing trees for their fuel value on ‘Wasteland’ or land that
is not usable for agriculture and cash crops is social forestry
activity. A plantation that is designed or managed and
operated to provide substantial amounts of usable fuel

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continuously throughout the year at a reasonable cost may
be called as ‘energy plantation’
Suitable tree species and land with favorable climate
and soil conditions of sufficient area are the minimum
resource required. Depending on the type of trees, the tree
life cycle, the geometry of leaf bearing branches that
determines the surface area facing the sun, the area
required for growing number of would be evaluated.
Combination of harvest cycles and planting densities that
will optimize the harvest of fuel and the operating cost, are
worked out. Typical calorie crops include 12000 to 24000
trees per hectare.
Raising multipurpose tree species on marginal lands is
necessary for making fuel wood available as well as for
improving soil condition. Trees for fuel wood plantations are
those that are capable of growing in deforested areas with
degraded soils, and withstand exposure to wind and drought.
Rapid growing legumes that fix atmospheric nitrogen to
enrich soil are preferred. Species that can be found in similar
ecological zones, and have ability to produce wood of high
calorific value that burn without sparks or smoke, besides
having other uses in addition to providing fuel are the

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multipurpose tree species most suited for bio-energy
plantations or social forestry programs.

AZADIRACTA INDICA (NEEM), LEUCAENA
LEUCOCEPHALA (SUBABUL), DERRIS INDICA
(PONGAM), AND ACACIA NILOTICA (BABOOL) are
examples of tree species for the above plantations.
AGRO-RESIDUES:















Biomass
[Year 2000]
Availability
Million tons/year

Coal equivalent
Million tons/year
Rice straw 100 60
Rice husk 30 20
Jute sticks 25 10
Wheat straw 50 38
Cotton stalks 20 17
Bagasse 30 25
Molasses 05 03
Coconut husk /
shell
02 03
Saw dust 05 06
Other 33 18
Total 100 200

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Estimated biomass residue production in India - 2010
Crop Area (Mha) Produce (MT) Residue
(dry) (MT)
R / P Type of
Residue
Rice 46.1 118.8 213.9 1.8
Straw, husk
Wheat 28.5 98.5 157.6 1.6
Straw
Jowar 5.3 6.1 12.2 2.0
stalk
Bajra 8.6 6.8 13.6 2.0
stalk
Maize 6.6 13.0 32.5 2.5
Stalk, cobs
Cotton 10.1 15.9 55.7 3.5
Seeds, waste
Jute 0.6 6.5 10.5 1.6
waste
Sugar Cane 5.5 463.5 185.4 0.4
Bagasse,
wastes
Source: Ravindranath et al, (2005)

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Table: Estimated potential for biomass energy : 10
15
J y
-
1
(10
15
J y
-1
= 320MW) Estimated total potential bio-fuel
resources harvested per year for various
countries(1978):
Source Sudan
Brazil India Sweden U.S.A.
Animal Manure 93 640 890 18 110
Sugar Cane 660 1000 430 --- 420
Fuelwood 290 3200 420 160 510
Urban Refuse 5 94 320 23 170
Municipal
Sewage
2 11 66 1 5
Other --- --- --- ---- 630
Total Potential 1000 4800 2100 200 1800
Present national
energy consumption 180 2700 5800 1500 72000
Ratio potential to
consumption
5.5 1.8 0.4 0.13 0.03
Ref: Vergara, W. and Pimental, D.(1978)’Fuels from
biomass’, in Auer, P.,(ed.),
Advances in Energy Systems and Technology, vol.1,
Academic Press, New York, pp 125-73

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Estimated quantity of waste generated in India (1999):
Waste Quantity
Municipal solid Waste 27.4 million tones/year
Municipal Liquid Waste
(121 Class1 and 2 cities)
12145 million liters/day
Distillary (243 nos) 8057 kilolitres/day
Press-mud 9 million tones/year
Food and Fruit processing waste 4.5 million tones /year
Dairy industry Waste
(C O D level2 Kg/m
3
)
50 to 60 million litres / day

Paper and Pulp industry Waste
(300 mills)
1600m
3
waste water/day
Tannery (2000 nos) 52500 m
3
waste water/day

Source: IREDA News, 10(3):11-12, 1999, V.Bhakthavatsalam

For details of characterization of biomass and analytical
procedures for determining properties, refer chapter 12,
Renewable Energy Engineering and Technology: Principles &
Practice, Edited by V. V. N. Kishore, 2009, T E R I, N. Delhi.

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Properties of Biomass
Physical Properties:
Moisture Content,
Particle Size and Size distribution
Bulk Density &
Specific gravity
Proximate Analysis:
Moisture Content
Volatile Matter
Fixed Carbon
Ash or mineral content
Chemical composition and heat content:
Elemental Analysis:
Carbon
Hydrogen
Oxygen
Nitrogen
Sulphur
Higher Heating Value:

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Chemical Composition:
Total Ash %,
Solvent soluble %,
Water Soluble %,
Lignin %,
Cellulose %,
Hemi-cellulose %
Wet and biodegradable biomass:
C O D value & B O D value,
Total dissolved solids & Volatile solids


BIOMASS PREPARATION FOR FUEL USE:
Preliminary treatment of biomass can improve its handling
characteristics, increase the volumetric calorific value, and
fuel properties for thermo-chemical processing. It can
increase ease of transport and storage.
Examples: CHIPPING, CHOPPING, DRYING, GRINDING,
BRIQUETTING ETC.
Fuel wood requires drying in air and chopping for best result
in cook stoves. Saw dust requires drying and briquetting to
increase its bulk density. Industrial boilers require uniformly
smaller sizes of wood for feeding their furnaces. Predrying of

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biomass to moisture levels of below 20% (oven dry basis)
enhances efficiency of combustion in cook stoves and
industrial boilers.
For production of high or medium pressure steam by
using biomass the best choice of equipment is the water
tube boiler. It has a large combustion area surrounded by
banks of vertical water tubes, which makes it suitable for
biomass fuels. Biomass fuels have a high content of volatile
matter and lower density and bulk density compared to solid
fossil fuels; as a result , biomass fuels need a large space
(relatively ) above the fuel bed to prevent flaring volatile
material from impinging upon the chamber wall and causing
damage to it over a period of time. Shell boilers are
unsuitable for biomass fuels because of the restricted
diameter of the furnace tube and high risk of damage to the
tube wall by flame impingement. Additionally demand for
uniform fuel quality and size by shell boilers are relatively
stricter.
Other types of end use equipment that are suitable for size
reduced biomass include cyclone furnaces, fluidized bed
systems and the controlled combustion incinerator. Cyclones
furnaces are adaptable to use of wood waste s fuel.

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Briquetting technologies:
Reference: ’Biomass feed processing for energy conversion’
P. D. Grover, in Biomass Energy Systems, Ed. P. Venkata
Ramana and S. N. Srinivas , T E R I and British Council, N.
Delhi(1996) pp 187-192

The proven high pressure technologies presently employed
for the briquetting of biomass are by the piston or the ram
type press and the screw or the extruder type machines.

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Both the machines give briquettes with a density of 1-1.2
gm/cc and are suitable as industrial solid fuels. The screw
type machines provide briquettes with a concentric hole that
gives better combustibility and is a preferred fuel. These
briquettes can also be more conveniently deployed in small
furnaces and even cook-stoves than solid briquettes
generated by a ram press.
Biomass densification-A solid(fuel) solution. N.Yuvraj,
Dinesh Babu, TERI, New Delhi. TERI Newswire, 1-15
December, 2001, page 3.
In India, briquettes are mostly made from groundnut
shell, cotton stalk, saw dust, coffee husk, bagasse, mustard
stalk and press mud. While the Southern region of India
produces briquettes mostly from groundnut shell and saw
dust, Western and
Northern regions produce bagasse, groundnut shell, cotton
stalk, mustard stalk and press mud briquettes. As a recent
addition municipal solid waste is also densified for use as
fuel in process industries (tea, tobacco, textile, chemical,
paper, starch, tyre re-treading, tiles, etc) for thermal
applications.

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Biomass & Bio-energy 14, no5-6, pp 479-488, 1998
‘A techno-economic evaluation of biomass briquetteing in
India’ A.K.Tripathi, P.V.R.Iyer and Tarachand Khandapal (I I
T, N.Delhi) [email protected]
Various types of raw materials used for briquetteing are:
ground-nut shells, cotton stalks, bagasse, wood chips, saw
dust, and forest residues. Pyrolysed biomass can also be
used. Materials can be fine granulated, coarse granulated or
stalky. Material may be dry or wet with various moisture
content. After a material is dried and crushed the pellets may
be formed under pressure with effect of heat,
Biomass & Bio-energy 18(3):223-228(2000)
‘Characteristics of some biomass briquettes prepared under
modest die pressures’ Chin, O.C and Siddiqui, K.M,
Universiti Sains Malaysia,31750,Perak, Malaysia
[email protected]

1. Discuss the sources and major kinds of biomass
available in India. How is the use of biomass for energy
justified? Explain biomass characteristics, properties
and suitable energy conversion methods.
2. For solid biomass used for combustion, what is the
significance of Proximate and Ultimate Analysis and

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HHV? Give typical values for saw dust, bagasse and rice
husk.
3. Discuss the woody, non-woody and organic waste
biomass available in India as resource for rural
supplementary energy / electricity.
4. How is sustainable use of biomass as energy source
possible and justified?
5. Explain biomass characteristics, properties and
suitable energy conversion methods.