Download - Generate power from-biomass
THINK ABOUT BIOMASS FOR POWER
SOURCES, CLASSIFICATION, CHARACTERISTICS, PROPERTIES, CRITERIA FOR CHOOSING TREE SPECIES
FOR ENERGY PLANTATIONS
BIOMASS CONVERSION METHODS
WOODY Agro AQUEOUS WASTE
IMPORTANCE OF ENERGY SOURCES
INCREASING POPULATION WITH
INCREASED PER CAPITA ENERGY CONSUMPTION
FOR
AGRICULTURAL ACTIVITIES ,TRANSPORT, INDUSTRY AND PRODUCTION OF ELECTRICITY
INCREASES THE DEMAND FOR ENERGY
THERE IS NEED FOR USING NON-FOSSIL SOURCES OF ENERGY
INCREASED PER CAPITA ENERGY CONSUMPTION
AS POPULATION HAS INCRESAED RAPIDLY
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1965 - 2005
AT PRESENT, WE DEPEND MOSTLY
ON COAL, OIL AND NATURAL GAS (FOSSIL FUELS).
THERE IS NEED FOR USING NON-FOSSIL SOURCES OF ENERGY
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At present, nuclear, wind and hydro are the
dedicated non-fossil fuel sources of energy that
contribute to electricity generation; supplementing
coal [major role], natural gas and oil. Contribution of
biomass is small.
What is the role of biomass in electricity generation at present?
• At present, nuclear, wind and hydro are the non-fossil fuel sources of energy that are fully used for electricity generation supplementing coal [major contributor], natural gas and oil.
• Where cane sugar industry is thriving, with bagasse as fuel, electricity is produced along with process steam for the sugar industry.
• Contribution of biomass gasification with combined cycle or micro-gas turbine for power is yet to be fully established.
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Change projected over a period of about twenty years.
The social, economic and environmental benefits of biomass
power are accepted for long term sustainability. The technologies
are progressively getting upgraded, attaining maturity, and
reaching commercialization. This is one of the renewable sources.
biomass
2002 to 2030
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Two recently published renewable energy text /
reference books
Available in India
(see next slides)
Reference book Chapters
12 to15
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The Energy and Resources Institute (TERI)
Another Reference book: Chapter 4 & 5
Fundamentals of Renewable Energy Sources
By
G. N. Tiwari and M. K. Ghosal
Narosa Publishing House, N.D. 2007
Chapter 4: Biomass, Biofuels and Biogas
Chapter 5: Biopower
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What does it take to produce energy from biomass?
Route
From BIOMASS to ENERGY
Route From BIOMASS to ENERGY
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What does it take to produce energy from biomass?
• Input for producing biomass: Seed, Land with soil, water, N P K + minor nutrients, sunlight and [manual + animal energy].
• How to Make it a usable Fuel: Biomass Residue from other uses maybe used as biofuel for combustion [heat-> Engine] or may be converted by conversion methods into derived S/L/G biofuel
• End use conversion devices: Thermodynamic cycles, Stoves, kilns, furnaces, steam turbines, gas turbines, engines and electricity Generators.
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BIOMASS UTILIZATION
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Environment Impact Assessment scope
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Discuss a set of factors that explain the slow
growth on the biomass utilization.
They include:
1. High costs of production
2. Limited potential for production
3. Lack of sufficient data on energy
transformations coefficients.
4. Low energy efficiency
5. Health hazard in producing and using biomass.
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Biomass conversion technologies
A number of modern biomass conversion
technologies are now available, which allow for
conversion of biomass to modern energy forms
such as electricity or gaseous (biogas, producer
gas), liquid (ethanol, methanol, fatty acid methyl
ester), and solid (biomass briquette) fuels.
Biomass conversion technologies can help in
meeting different types of energy needs,
particularly electricity. Key technologies for
power generation that have been promoted in
India are gasification, combustion,
cogeneration and biomethanation.
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Technology specific incentives by MNRE
• Improved cook stoves: Central government subsidy is provided in the range of Rs. 80- to Rs. 150- per fixed model cook stove and Rs. 50- to Rs. 75- per portable cook stove. There are incentives for construction and maintenance, dealership support, support for publicity, technical backup and training.
• Biogas: A central subsidy of up to Rs. 6000- per plant for family-size biogas plants. Rs. 44,000 to 200,000 for community biogas plants. Rs. 44,000 to 150,000 for institutional biogas plants and concessional loans are made available through various schemes. The financial incentives (grants) are in the range of Rs. 2,000- to 3,000 – per cubic meter for large biogas plants. Incentive is also provided for operation and maintenance. Thus the government meets a significant part of the cost of the community biogas plant.
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Technology specific incentives by MNRE
Biomass Gasifiers: Capital subsidy up to 60 % of the cost of a biomass gasifier and additional incentives up to 100 % are made available for selected components of village electrification projects. Additional incentives are also available for selected sited and other components. Soft loans are extended through IREDA for the remaining costs.
Biomass / bagasse co-generation: Capital subsidy of Rs. 4.5 million/ MW subject to a maximum of Rs. 81 million per project for demonstration projects in the joint venture or independent power producer (IPP) mode in co-operative / public sector sugar mills; soft loans (1% to 3% interest subsidy on loans) for commercial projects is provided by the MNES.
Source: MNES 2001; Note 1US$ = Rs. 40- in 2002
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What is Biomass? What are its sources and how are
they classified?
BIOMASS • Biomass is material derived from plant and
animal sources.
• Products of Forestry, Agriculture, Urban and Industrial Waste Disposables are sources of biomass that may be converted into biofuels.
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Sources of biomass
Primary:
• Forestry-Dense, Open;
• Social Forestry
• Agriculture,
• Animal Husbandry,
• Marine
Secondary:
• Industry,
• Municipal Waste
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Technological advancements in biomass energy conversion:
• This comes from three sources – (1) enhanced efficiency of biomass energy conversion technologies, (2) improved fuel processing technologies and (3) enhanced efficiency of end-use technologies.
• Versatility of modern biomass technologies to use variety of biomass feedstock has enhanced the supply potential. Small economic size and co-firing with other fuels has also opened up additional application.
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Classification of biomass based on physicochemical properties:
• WOODY,
• NON-WOODY or AGRO RESIDUE (cultivated),
• WET [AQUEOUS] ORGANIC WASTE (effluents)
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Forests
Discuss forests as multifunctional natural resource that can also yield
woody biofuel.
Forest resource base-India
• 1 % of World's forests on 2.47 % of world's geographical area
• Sustaining 16 % of the world's population and 15 % of its livestock population
• Forest area cover—63.3 mill. hectares, is 19.2% of the total geographical area of India.
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Causes of tremendous pressure on Forest resource base
• Exponential rise in human and livestock population
• increasing demand on land allocation to alternative uses such as agriculture, pastures and development activities.
• Insufficient availability, poor purchasing power of people in rural areas for commercial fuels like kerosene & LPG drives poor people to use firewood inefficiently as a cooking fuel.
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• A minimum of 33 % of total land area under
forest or tree cover from present 19.2%
cover.
•Recognize the requirements of local people
for timber, firewood, fodder and other non-
timber forest produce-- as the first charge on
the forests,
• The need for forest conservation on the
broad principles of sustainability and
people’s participation.
The National Forest Policy
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15.5 m. ha of degraded forest land has natural root
stock available, which may regenerate given proper
management under the JFM
•Another 9.5 m. ha is partially degraded with some
natural rootstock, and another six m. ha is highly
degraded. These last two categories together
constitute another 15.5 m. ha, which requires
treatment through technology-based plantation of
fuel, fodder and timber species with substantial
investment and technological inputs.
Joint Forest Management system.
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• Fuelwood and fodder plantations to meet
the requirements of rural and urban
populations.
•Plantations of economically important
species (through use of high-yielding clones)
on refractory areas to meet the growing
timber requirement.
• Supplementing the incomes of the tribal
rural poor through management and
development of non-timber forest products.
The emphasis will be on:
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• Developing and promoting pasture on suitable
degraded areas.
• Promoting afforestation and development of
degraded forests by adopting, through micro-
planning, an integrated approach on a watershed
basis.
• Suitable policy initiatives on rationalization of tree
felling and transit rules, assured buy-back
arrangements between industries and tree
growers, technology extension, and incentives like
easy availability of institutional credit etc.
The emphasis will be on cont…
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To sum up, tropical India, with its adequate
sunlight, rainfall, land and labour,
is ideally suitable for tree plantations.
With the enhanced plan outlay for
forestry sector and financial support
from donor agencies, the country will
be able to march ahead towards the target
of 33 percent forest cover.
Forestry in the New Millenium:
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What are agro-forestry, ‘trees-outside-forests [T o F]’ and
Energy Plantation?
Other than Forests we have thinner sources of trees.
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Integrates trees with farming, such as lines
of trees with crops growing between them
(alley cropping), hedgerows, living fences,
windbreaks, pasture trees, woodlots, and
many other farming patterns.
Agro-forestry increases biodiversity,
supports wildlife, provides firewood,
fertilizer, forage, food and more, improves
the soil, improves the water, benefits the
farmers, benefits everyone.
Agro-forestry
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agroforestry - A dynamic, ecologically based
natural resources management system that,
through the integration of trees in farmland and
rangeland, diversifies and sustains production for
increased social, economic and environmental
benefits for land users at all levels. Agroforestry,
the intercropping of woody and non-woody plants,
although age-old in practice, has now established
itself as a new science.
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Energy Plantation: Growing trees for their fuel
value
• ‘Wasteland’-- not usable for agriculture and cash crops, useful for a social forestry activity
• A plantation that is designed or managed and operated to provide substantial amounts of usable fuel continuously throughout the year at a reasonable cost-- 'energy plantation'
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Criteria for energy plantation-1
• 'Wasteland‘--sufficient area, not usable for agriculture and cash crops, available for a social forestry activity
• Tree species favorable to climate and soil conditions
• Combination of harvest cycles and planting densities that will optimize the harvest of fuel and the operating cost--12000 to 24000 trees per hectare.
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Criteria for energy plantation-2
• Multipurpose tree species-fuel wood supply & improve soil condition
• Trees 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
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Criteria for energy plantation-3
• Species that can be found in similar ecological zones
• Produce wood of high calorific value that burn without sparks or smoke
• Have other uses in addition to providing fuel -- multipurpose tree species most suited for bio-energy plantations or social forestry
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Give examples of trees suitable for Indian climatic zones
Fast growing nitrogen fixing trees that can withstand arid wasteland
Indian TREES / WOOD:
• Leucaena leucocephala (Subabul)
• Acacia nilotica (Babool)
• Casurina sp
• Derris indica (Pongam)
• Eucalyptus sp
• Sesbania sp
• Prosopis juliflora
• Azadiracta indica (Neem)
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Forage legume = vegetable,
• Regeneration of earthworm populations in a
degraded soil by natural and planted fallows under
humid tropical conditions
• Use of Leucaena leucocephala: Fodder,
fuelwood, erosion control, nitrogen fixation,
alley cropping, staking material
• Ntrogen fixation legume: Due to Leucaena
leucocephala crop wasteland is reclaimed
Leucaena leucocephala Crop Use:
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neem tree (Azadirachta indica)
Tree used in windbreaks, fuel wood plantations, and silvo-pastoral systems, for dry zones and infertile, rocky, sandy or shallow soils. The leaves, bark, wood and fruit of the neem tree either repel or discourage insect pests, and these plant parts are incorporated into traditional soil preparation, grain storage, and animal husbandry practices.
Several neem-based biological pest control (BPC) products have been developed. The neem tree can provide an inexpensive integrated pest management (IPM) resource for farmers, the raw material for small rural enterprises, or the development of neem-based industries.
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JATROPA CURCAS [PHYSIC NUT]
Jatropha curcas [ physic nut], is unique among
biofuels. Jatropha is currently the first choice for
biodiesel. Able to tolerate arid climates, rapidly
growing, useful for a variety of products,
Jatropha can yield up to two tons of biodiesel fuel
per year per hectare.
Jatropha requires minimal inputs, stablizes or even
reverses desertification, and has use for a variety of
products after the biofuel is extracted.
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Jatropha, continued
What makes Jatropha especially attractive to India is that it is a drought-resistant and can grow in saline, marginal and even otherwise infertile soil, requiring little water and maintenance.
It is hearty and easy to propagate-- a cutting taken from a plant and simply pushed into the ground will take root. It grows 5 to 10 feet high, and is capable of stabilizing sand dunes, acting as a windbreak and combating desertification.
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Acacia nilotica: babul
A useful nitrogen fixing tree found wild in the
dry areas of tropical Africa and India
plantations are managed on a 15-20 year
rotation for fuel wood and timber.
calorific value of 4950 kcal/kg, making
excellent fuel wood and quality charcoal. It
burns slow with little smoke when dry
The bark of ssp. indica has high levels of
tannin (12-20%)
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Pongam pinnata
A nitrogen fixing tree for oilseed
Also called as Derris indica, karanga,
Produces seeds containing 30-40% oil.
is a medium sized tree that generally attains
a height of about 8 m and a trunk diameter of
more than 50 cm
natural distribution of pongam is along coasts
and river banks in India and Burma
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HYDROCARBON PLANTS, OIL PRODUCING SHRUBS:
• Hydrocarbon-- Euphorbia group
• & Euphorbia Lathyrus
• OIL Shrubs-- Euphorbia Tirucali
• Soyabean
• Sunflower
• Groundnut
• Jatropa
Discuss Properties & characteristics of
biomass
Wood – Agro residue – aqueous Waste
Properties of Solid Biomass :
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Chemical Composition of Solid Biomass :
• Total Ash %,
• Solvent soluble %,
• Water Soluble %,
• Lignin %,
• Cellulose %,
• Hemi-cellulose %
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Elemental Composition:
• Carbon
• Hydrogen
• Oxygen
• Nitrogen
• Sulphur
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Properties of Wet and Biodegradable biomass:
• C O D value
• B O D value
• Total dissolved solids
• Volatile solids
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What intervention is needed in traditional and primitive
rural utilization of biomass as fuel?
By overcoming poor purchasing power for LPG /Kerosene [to eliminate biofuel]
and investing in Energy Plantations
Make biofuel use economical and use efficient with new technology.
Problems in use of bio-fuels
Traditional biomass use is characterized by
• low efficiency of devices, scarcity of fuelwood, drudgery associated with the devices used,
• environmental degradation (such as forest degradation) and low quality of life.
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• In the twenty-first century, energy is not as it
always was.
• Yesterday’s world was entirely dependent on
biomass, particularly wood for heating and
cooking.
• A century ago biomass was eclipsed by fossil
fuels. Biomass is generally viewed with disfavor
as something associated with abject poverty.
• Yet there is another side to biomass; there is
now something of a resurgence going on. As
fossil fuel prices increase, biomass promises (?)
to play a more active role as a utility fuel, a motor
vehicle fuel, and a supplement to natural gas.
Rural India & ‘bio-energy’ • Before the advent of fossil fuels, energy needs for all activities
were met by renewable sources such as solar, biomass, wind, animal and human muscle power.
• In rural India, traditional renewables such as biomass and human and animal energy continue to contribute 80 % of the energy consumption [MNES, 2001].
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Share of bio-energy in primary energy consumption in India
In India, the share of bio-energy was estimated at
around 36 % to 46 % of the total primary energy
consumption in 1991 [Ravindranath and Hall, 1995], and has
come down to around 27 % in 1997 [Ravindranath et al.,
2000].For cooking, water heating and village industry,
use of firewood may have been substituted by LPG,
kerosene and diesel. Though availability has improved,
now prices are increasing. Improved cook stoves?
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Eliminate excess use of fuel wood as rural Heating and
cooking Fuel: Fuelwood accounts for 60% of the total fuel
in the rural areas. In urban areas, the consumption pattern
is changing fast due to increased availability of commercial
fuel (LPG, kerosene, and electricity). During 1983–1999, the
consumption of traditional fuel declined from 49% to 24%
and LPG connection to households increased from 10% to
44%. Developments in the petroleum sector facilitate the
availability of (subsidized) LPG and kerosene, the two most
important forms of energy preferred as substitutes for
fuelwood in households for cooking.
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Commercial fuel =
(LPG, kerosene, and
electricity).
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What are modern bioenergy technologies, barriers to their
development and what programmes are needed?
Biomass conversion to usable fuels and the end use devices are to be
developed and marketed
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India has over two decades of experience of implementing
bioenergy programmes. The Ministry of Non-conventional
Energy Sources (MNES or MNRE), the prime mover of the
programmes in India, has now responded with a
comprehensive renewable energy policy to give a
further fillip to the evolving sector. The need for climate
change mitigation provides an opportunity for promoting
the renewable energy (RE) sector. This calls for an
assessment of the policy barriers to the spread of
bioenergy technologies (BETs) in India.
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• The experience shows that despite several financial
incentives and favourable policy measures, the rate of
spread of BETs is low because of the existence of
institutional, technical, market and credit barriers.
• These barriers are by and large known, but what still
remains to be understood is the type and size of barriers
from the stakeholders’ perspective, which varies for a
given technology and the stakeholder.
• Policy options suggested to overcome such barriers
include:
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Bioenergy technologies : Remove Barriers:
(1) rational energy pricing: Explain the withdrawal of subsidy to Oil &
Gas products from economic & environmental point of view.
(2) Incentives for bioenergy to promote private sector participation,
(3) institutions to empower and enable community participation,
(4) financial support for large-scale demonstration programmes and for
focused research and development on bioenergy technologies
(BETs) for cost reduction and efficiency improvement, and finally,
(5) favourable land tenurial arrangements to promote sustained
biomass supply.
The global mechanisms for addressing climate change such as the
Clean Development Mechanism (CDM) and the Global Environment
Facility (GEF) provide additional incentives to promote BETs.
•Offer opportunities to conserve biomass
through efficiency improvements, and for
conversion to electricity and liquid and
gaseous fuels.
• Bio-energy technologies based on
sustained biomass supply are carbon
neutral and lead to net CO2 emission
reduction if used to substitute fossil fuels.
Modern Bio Energy Technologies
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Bio Energy Technologies and their products
Thermo-chemical production of fuels from Biomass
Pyrolysis, Gasification and Catalytic conversion
( Techno-economic development is a research area for these technologies)
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Biomass Fast Pyrolysis to Transportation Fuels
• Biomass fast pyrolysis is a thermochemical process that
converts feedstock into gaseous, solid, and liquid products
through the heating of biomass in the absence of oxygen.
• The liquid is called ‘Bio-oil’ and can be upgraded as a usable fuel
for an engine. A techno-economic study of transportation
biofuels via fast pyrolysis and bio-oil upgrading is needed in
India. The upgraded pyrolysis oil products may be modeled as
C8 and C10 hydrocarbons.
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An overall description of the biomass fast pyrolysis process to
produce naphtha and diesel is shown in Figure. To produce
hydrogen employ optional equipment. Biomass with 25%
moisture content is dried to 7% moisture and ground to 3-mm-
diameter size prior to being fed into a fluid bed pyrolyzer
operating at 480°C and atmospheric pressure. Standard
cyclones remove solids consisting mostly of char particles
entrained in the vapors exiting the pyrolyzer. Vapors are
condensed in indirect contact heat exchangers, yielding liquid
bio-oil that can be safely stored at ambient conditions prior to
upgrading to transportation fuels.
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Non-condensable gases are recycled to the pyrolysis reactor
after being combusted to provide process heat. Also,
pyrolysis solid products may be sent to a combustor to
provide heat for the drying and pyrolysis process. Excess
solid char is a low-heating-value coal substitute. Bio-oil
upgrading generates a fuel compatible with existing
infrastructure. Ash content can cause fouling and plugging of
high-temperature equipment. Minerals catalyze thermal
decomposition reactions that are detrimental to the
production of quality pyrolysis oil. Biomass washing using
water or acid-removal techniques can reduce alkali content
in biomass.
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Hydrotreating and hydrocracking (catalytic processing with hydrogen)
are commonly employed in the petroleum industry to remove undesired
compounds such as sulfur from crude oil and to break large
hydrocarbon molecules to produce clean naphtha and diesel.
Bio-oil typically contains significant quantities of oxygenated
compounds that are undesirable for combustion in vehicle engines.
Hydrotreating can convert oxygen found in bio-oil to water and carbon
dioxide molecules, leaving hydrocarbons that are suitable for internal
combustion engines.
Complex hydrocarbon compounds are found in bio-oil, and
hydrocracking is a potential method to decompose these heavy
compounds into naphtha and diesel.
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Biomass gasification
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Updraft Gasifier • Here, the biomass
moves down from the top of the gasifier while the gases released being light move up, resulting in a counter-current. The quality of producer gas obtained from the up-draft gasifier is fair since it has impurities like tar.
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However, this resultant producer
gas has a higher capacity to
generate heat on burning (due to
the impurities) and can be used
well for heat generation
activities.
Downdraft Gasifier
• Biomass moves down from the top of the gasifier and the resultant gas also moves downward—a co-current process. The gas quality is good though it generates less heat on burning. The gas released from such gasifiers is used mainly for electricity generation.
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How can biomass supplement coal as a feedstock for power
plants?
For decentralised small / medium scale power plants
Biomass Power Programmes are available
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Biomass energy is not necessarily the ‘poor man’s
fuel’, its role is rapidly changing for a combination of
environmental, energy, climatic, social and
economic reasons. It is increasingly becoming the
fuel of the environmentally-conscious, rich society.
The use of biomass energy has many pros and
cons. One of the major barriers confronting
renewable energy is that the conventional fuels do
not take into account the external costs of energy,
such as environmental costs.
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It is important to create a new situation in which all
sources of energy are put on a more ‘equal footing’.
For biomass energy, which has little or no
environmental costs, the internalisation of the cost
of energy could be a major determinant for its large-
scale implementation. This, together with
agricultural productivity and technological advances,
could be a key determinant in ensuring greater
competitiveness with fossil fuels.
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The Biomass Power Programme of India has reached the take off
stage, after dedicated and sustained efforts over the last decade.
The total potential is about 19,500 MW, including 3,500 MW of
exportable surplus power from bagasse-based co-generation in
sugar mills, and 16,000 MW of grid quality power from other
biomass resources.
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The Program could CONSISTS OF the following Components:
· Interest Subsidy for Bagasse/Biomass Co-generation projects,
including IPP mode projects;
· Interest Subsidy for Biomass Power Projects, including captive power
projects;
· Grants to MW-scale projects with 100% producer gas engines, and
Advanced Biomass Gasification projects;
· Promotion of Industrial Co-generation projects in core industry sector
for surplus power generation;
· Promotional Incentives for awareness creation, training and
preparation of Detailed Project Reports; and
· Grants for Biomass Resource Assessment Studies.
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BIOMASS INTEGRATED GASIFIER /GAS TURBINE (BIG/ GT) TECHNOLOGY
• HIGH THERMODYNAMIC CYCLE EFFICIENCY
GAS TURBINES TECHNOLOGY IS MADE AVAILABLE NOW AT REASONABLE COSTS
LOW UNIT CAPITAL COST AT MODEST SCALES FEASIBLE
IT IS EXPECTED THAT THIS TECHNOLOGY WILL BE COMMERCIALLY SUCCESSFUL IN THE NEXT TEN YEARS.
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Briquetting: Briquetting
improves the energy density of
loose biomass, which is either
charred and compacted or
directly compacted in the form
of briquettes.
Biomass briquettes made
through manual processes can
be used as cooking fuel in
homes. Briquettes produced
through mechanical processes
can be used in boilers and
furnaces.
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Fuel derived from compacting the biomass into
dense block is known as Briquette. It is cheaper
and requires no other raw material and produce
heat equivalent to other fuel. Now a days
biomass briquetting is used by the same
industries where the low-density biomass is
produced. Jute waste, groundnut shell, coffee
husk, coir pith and rice husk is used for
Briquetting.
What is Biomass Briquetting?
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Biomass briquettes in Malawi.
• The briquette evaluation was made in terms of physical and chemical characteristics (like material content, size, weight, energy content), costs for the fuel and usability in household cooking stoves. The feasibility of the production method for each briquette type was also evaluated.
• The briquettes were compared with the characteristics of firewood and charcoal.
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Agro-residues and agro-industry residues-1
• Agricultural or agro-industrial biomass is
generally difficult to handle because of its
bulky and scattered nature, low thermal
efficiency and copious liberation of smoke
during burning. It will be useful to compress
them into manageable and compact pieces,
which have a high thermal value per unit
weight.
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Agro-residues and agro-industry residues-2
• Biomass residues and by products are
available in abundance at the agro processing
centres (rice husk, bagasse, molasses,
coconut shell, groundnut shell, maize cobs,
potato waste, coffee waste, whey), farms
(rice straw, cotton sticks, jute sticks).
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briquetting or pelleting
• The process is called
biomass briquetting or pelleting.
• Compressed biomass briquettes are usually cylindrical in shape with a diameter between 30 to 90 mm and length varying between 100 to 400mm.
• Briquetting consists of applying pressure to a mass of particles with or without a binder and converting it into compact aggregate. Ram type and screw type machinery are used for the manufacture of briquettes.
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Briquetting technology
• Ram type consists of a plunger or rod which forces the material received from a hopper into a die, which is not usually heated by external means.
• The screw type machine employs a screw auger which forces the material into a pipe heated by electricity.
• The choice of the type of machinery depends on many factors.
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Ram type [piston type] briquetting machine
• Ram type consists of a
plunger or rod which
forces the material
received from a hopper
into a die, which is not
usually heated by
external means.
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Ram type briquetting press
• Common in India, alternate to screw type.
• Material is compressed in horizontal press, made into a cylindrical continuous log; Cut to pellets later.
• Log diameter is 50 mm for a 500 kg per hour machine and 90 mm for a 1500 kg / hr machine
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Screw type briquetting machine
• The screw type machine
employs a screw auger
which forces the
material into a pipe
heated by electricity.
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Screw type briquetting Press
• The material is extruded under compression continuously in the form of a log, under screw.
• These logs are partially carbonized and free of volatile compounds.
• They can supplement charcoal / lignite as solid fuel for small scale uses.
• Wear of screw is a problem and designers of machine have solved this.
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PELLETISING
• Biomass material is compressed
through many holes by giving very high
pressure from rollers to the material.
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Preparing biomass for pellet making
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PELLETISING: High pressure, smaller size
• In pelletising, the biomass material
is compressed through many holes by giving very
high pressure from rollers to the material.
• The stick is continuous but the size of pellet is
smaller (6-25 mm in diameter) than briquettes.
• Pelletizing is more efficient and recognized as a
good method because of low investment.
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• Pelletizing, though introduced very recently, is
considered to be most wanted method due to its
high bulk density.
• Ring and Flat Die are two types found in this
category.
• The Ring die method is mostly used for making
animal feed, which has high bulk density.
• The flat die is used for low bulk density.
PELLETISING: Ring and Flat Die
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Combustion: A chemical process _ Oxidation of reduced forms of carbon
and hydrogen by free radical processes. Chemical properties of the bio-
fuels determine the higher heating value of the fuel and the pathways of
combustion.
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Table: 1.
Chemical composition of some biomass material
Species Total ash% Lignin% Hemi-
cellulose%
Cellulose %
Bagasse 2.2 18.4 28.0 33.1
Rice Straw 16.1 11.9 24.1 30.2
Wheat Straw
6.0 16.0 28.1 39.7
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To determine the quantity of air required for complete combustion
• To determine the air, the ultimate analysis is useful.
• C + O2 = CO2 +97644 cal /mole [[15 o C]
• H2 +O2 = H2O + 69000 cal / mole [15 o C]
• Excess air % = (40*MCg)/(1- MCg) where MCg is moisture
content on total wt basis (green). For typical biomass fuels at
50 % moisture content, for grate firing system about 40%
excess air may be required.
• For suspension fired and fluidized bed combustion, air
required may be 100 % excess
• Distribution of air and whether it is pre-heated is also
important
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Higher Heating Value
• Calorific value of a fuel is the total heat produced when a unit mass of a fuel is completely burnt with pure oxygen. It is also called heating value of the fuel. When the c.v. is determined, water formed is considered as in vapour state, net c. v. is got.
• Gross calorific value or higher heating value of a fuel containing C, H and O is given by the expression:
• Cg =[C x 8137 + (H--O/8) x 34500]/100 where C, H and O are in % and Cg is in calories.
• Net calorific value is the difference between GCV and latent heat of condensation of water vapor present in the products
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Fluidized Bed Combustion
• The remainder of the heat is available for direct
transmission to heat transfer surfaces immersed within the
bed; in boiler applications these comprise a set of steam
raising tubes.
• The heat transfer to immersed surfaces is uniformly high in
comparison with the variation of radiation heat transfer
through a conventional combustion chamber.
• Less heat transfer surface is required for a given output
and a boiler system occupies a smaller volume.
Liquid Fuels from Biomass
Ethanol & Biodiesel
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Liquid and gaseous transport fuels derived from a range of
biomass sources are technically feasible. They include
• methanol,
• ethanol,
• dimethyl esters,
• pyrolytic oil,
• Fischer- Tropsch gasoline and distillate and
• Biodiesel from (i) Jatropha , Pongamia pinnata, Salvadora
persica, Madhuca longifolia and
• ( ii) hydrocarbon from Euphorbia species.
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Sugar cane, like other plants, absorbs carbon dioxide from the
atmosphere during photosynthesis. Burning ethanol made from
sugar thus returns to the atmosphere what was recently there, rather
than adding carbon that was previously underground. Unfortunately,
turning sugar cane into ethanol uses more energy, and thus causes
more greenhouse-gas emission, than making petrol from crude oil.
Nevertheless, says Lew Fulton of the International Energy Agency, a
sister body of the OECD, studies suggest that Brazil's present
method of making ethanol fuel from sugar leads to net savings of
about 50% in greenhouse-gas emissions per kilometre travelled,
compared with running cars on petrol.
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• Photosynthetic organisms include plants, algae and some
photosynthetic bacteria.
• Photosynthesis is the key to making solar energy available
in useable forms for all organic life in our environment.
• These organisms use energy from the sun to combine
water with carbon dioxide (CO2) to create biomass.
• While other Biofuels Programs can focus on terrestrial
plants as sources of fuels,
• Microalgae Program can be concerned with photosynthetic
organisms that grew in aquatic environments.
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Microalgae are, as the name suggests, microscopic
photosynthetic organisms. Like macroalgae, these organisms
are found in both marine and freshwater environments.
Microalgae generally produce more of the right kinds of
natural oils needed for biodiesel.
Biologists have categorized microalgae in a variety of classes,
mainly distinguished by their pigmentation, life cycle and basic
cellular structure. The four most important (at least in terms of
abundance) are: The diatoms (Bacillariophyceae), The green
algae (Chlorophyceae), The blue-green algae
(Cyanophyceae) and The golden algae (Chrysophyceae).
Algae-for-fuel
• Among algal fuels' attractive characteristics:
• they do not affect fresh water resources,
• can be produced using ocean / wastewater,
• are biodegradable
• relatively harmless to the environment if spilled.
• As of 2008, such fuels remain too expensive, with the cost of
various algae species typically between US$5–10 per kg dry
weight.
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Algae cost more per pound yet can yield over 30
times more energy per acre than other, second-
generation biofuel crops.
It is claimed that algae can produce more oil in
an area the size of a two-car garage than an
football field of soybeans, because almost the
entire algal organism can use sunlight to
produce lipids, or oil.
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• Studies show that algae can produce up to 60% of their
biomass in the form of oil.
• Because the cells grow in aqueous suspension where
they have more efficient access to water, CO2 and
dissolved nutrients, microalgae are capable of producing
large amounts of biomass and usable oil.
• Either high rate algal ponds or photo-bioreactors may be
used for the growing of the algae.. This oil can then be
turned into biodiesel used in automobiles. Regional
production of microalgae and processing into biofuels will
provide economic benefits to rural communities.
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Name a recently published Reference book and point out the bioenergy related chapters in it.
See the next three slides
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Reference book Chapters 12 to15
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The Energy and Resources Institute
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The promotion of energy using biomass available
in form of natural waste such as agricultural
residue, sugarcane bagasse, banana stems,
organic effluents, cattle dung, night soil, fuelwood
and twigs holds considerable promise. A National
Programme on Biomass Power/Cogeneration was
launched to optimise the use of a variety of
forestry-based and agro-based residues for power
generation by the adoption of state-of-the-art
conversion technologies.
Reference book from T. E. R. I.
Chapters 12 to15
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SOME MORE BOOKS ON BIOENERGY
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