BIOMASS TO
ENERGY
What is meant by Biomass
• Materials produced by metabolic activities of biological
systems (plants and animals) and/or products of their
decomposition or conversion
• The materials are based on carbon compounds
• The chemical and energetic value of those materials is
based on the carbon-carbon and carbon-hydrogen bond
• Biomass suitable for utilization must have a net heating
value
• Biomass is infact collected and stored solar energy
Sources of Biomass
• agriculture
• residues from forestry, specific industries (e.g. furniture
production, saw dust), food processing
• solid municipal and industrial wastes
• used wood e.g. from old furniture, used timber
• marine systems: the oceans of our world contain much
more biomass than existing on the continents (but they are
not regarded as a source of biomass for energetic
utilization)
Sources of Biomass
• Bio Mass from cattle manure, agricultural waste,
forest residue and municipal waste.
• Anaerobic digestion of livestock wastes to give bio
gas
• Fertilizers as by product.
• Average electricity generation of 5.5kWh per cow
per day!!
Carbon Neutral
• Energy is produced from biomass by basically burning
organic matter to release its stored chemical energy that it
has accumulated through the process of photosynthesis.
Using biomass contributes very little to the build-up of
greenhouse gases. Although plants will release their stored
carbon dioxide (CO2) when burned, that CO2 is recaptured
and used by other plants as they grow. Therefore,
theoretically there is no net gain of carbon dioxide because
of a cycle of usage
Bio Mass: contribution in Energy
• Biomass already supplies 14 % of the world’s
primary energy consumption. On average, biomass
produces 38 % of the primary energy in developing
countries.
• USA: 4% of total energy from bio mass, around
9000 MW
• INDIA is short of 15,000 MW of energy and it costs
about 25,000 crores annually for the government to
import oil.
Biomass Utilization & Conversion
•
•
•
•
•
Densification
Microbial treatment
Thermal treatment
Chemical treatment
Mechanical processes
Densification
BIOMASS DENSIFICATION is the process of compacting low a
bulk density material into a product of high density Densification
has stimulate a great deal of interest worldwide in recent years as
a technique of beneficiation of residues for utilization as energy
source. Densified biomass is mostly in the form of briquettes in
developing counties and in the form of pellets in developed
countries.
• Briquettes
Briquetting is the process of densification of biomass to produce
homogeneous, uniformly sized solid pieces of high bulk density
which can be conveniently used as a fuel.
• Pellets
Pelletizing is closely related to briquetting except that it uses
smaller dies (approximately 30 mm) so that the smaller products
are called pellets.
Briquettes
• Piston Press
In the die and punch technology, which is also known as ram and
die technology, biomass is punched into a die by a reciprocating
ram with a very high pressure thereby compressing the mass to
obtain a compacted product. The standard size of the briquette
produced using this machine is 60 mm, diameter. The power
required by a machine of capacity 700 kg/hr is 25 kW. The ram
moves approximately 270 times per minute in this process.
Piston Press
Briquettes
Screw Press
In this process, the biomass is extruded continuously by one
or more screws through a taper die which is heated externally
to reduce the friction. Here also, due to the application of high
pressures, the temperature rises fluidizing the lignin present
in the biomass which acts as a binder. The outer surface of
the briquettes obtained through this process is carbonized
and has a hole in the centre which promotes better
combustion. Standard size of the briquette is 60 mm
diameter.
Screw Press
Pellets
• Flat/disk Type
• The flat die type features a circular perforated disk on which
two or more rollers rotate. The ring die press features a
rotating perforated ring on which rollers press onto the inner
perimeter. Large capacity pelletizers are available in the
range of 200 kg/h to 30 ton/h thus pellets press capacity is
not restricted by density of the raw material as in the case
of piston or screw presses. Power consumption falls within
the range of 15 – 40 kWh/ton.
Flat/disk Type
Microbial Treatment
• Long traditions in many cultures in the field of food
processing
e.g.
beer
brewing,
alcoholic
fermentation, preservation technologies as lactic
acid fermentation
• Waste treatment in agriculture and food industry by
aerobic treatment (composting) and anaerobic
fermentation
• Treatment of municipal and industrial waste water
• (Pre)Treatment of solid waste containing organic
materials
Aerobic Processes
Agricutural wastes: Treatment of solid
Traditional method: urban waste:
composting
Technology with
good prospects
Pretreatment of
hazardous waste
Treatment of
gaseous phases for
de-odorizing
(e.g. compost
filters in fish
industry)
Biomass contributions to energy supply :
electrical energy
•
•
•
•
Wood, other biomass (Combustion, Pyrolysis)
Biogas
Waste, sewage sludge (incineration, Fermentation)
Chemical Processes: hydrogenation,
transesterification
• BTL (Biomass to liquid)
Wood Incineration units
• Normally chopped wood or chopped woody
residues are used as feeding materials for large
cogeneration plants
• For the heating of households pelletised
materials are available. By using them the
incineration
process
can
be
operated
automatically. The cost for the pelletized wood in
relation to mineral oil come to about 2/3
19.5 MW – Plant for gerating heat and
electricity in Germany
•
•
•
•
Input „fresh“ and old wood chops, 5.33 t/h max
Steam production: 25.5 t/h
Operation 8000 hours per year
Energy output electrical from 3.8 to 5.1 MW
depending on heat delivery for the households
• Energy output thermal: maximum 10 MW
Wood – a big potential of the forests
• In Germany there are growing about 60 millions
of m3 wood per year, that can be harvested
• Thats is an energtic equivalent of about 1.5
TWh/a
• Compared to the actual energy consumtion of
Germany this is a potential of 50%
• Actual energetic utilization of wood comes to
0.09 TWh/a
Wood burning in stoves
• Domestic heating with wood is still by far
the largest market for bio-energy
• Dramatic improvements of technology in
domestic heating equipment
• Improved tiled stoves, advanced logwood
boilers, woodchip boilers, pellet boilers and
pellet stoves.
• Pourable wood-based fuel is also available
Tiled stoves
Pellet Boilers and Stoves
Logwood boiler
Woodchip boilers
Energy content of wood based substrates
average data
water content
calorific value
oil equivalent
(%)
(kWh/kg )
L oil/m3
Pieces
20
4
165
Pellets
10
5
325
Chops
20
4
100
Saw dust
40
2.6
70
----------------------------------------------------------------------------------------------Wheat
15
4
400 L/1000 kg
Pyrolysis
Heating in the absence of air.
Pyrolysis of biomass generates three different energy
products in different quantities: coke, gas and oils.
Conversion of solid fuels into combustible gas mixture
(CO + H2 + CH4)
TYPES
• Fluidized-bed fast pyrolysis
• Microwave-assisted pyrolysis
• Slow pyrolysis
• Intermediate pyrolysis
Pyrolysis: Advantages
It can achieve significantly higher electrical efficiencies (22 % to
37 %) compared to biomass combustion technologies with steam
generation and standard turbine technology (15 % to 18 %).
The improved electrical efficiency of the energy conversion via
pyrolysis naturally means that the potential reduction in CO2 is
greater than with combustion. The formation of NOx compounds
can also be greatly reduced and the removal of pollutants is
generally in most cases.
For power plants with integrated biomass gasification in the range
3 to 20 MW electricity, fluidized bed gasification of biomass under
atmospheric pressure, coupled with gas turbines using the Cheng
cycle or gas and steam turbines appear to be the most promising
technology at present in technical and economic terms. For
combined heat and power stations with capacities up to about 2
MW electricity, gas use in gas-fired engines is, at the moment,
more attractive than gas turbines.
What is a Biogas Plant
• Basically Methane & CO2 Gas Producer.
• Methane – Odorless, Colorless, Good Calorific
Value, Green House Gas
• Sources : Animal Manures, excreta, kitchen
waste, Industrial Chemical Processes, Sea
Water Bed, etc.
• Animal Manure & Excreta contributes around 16
% of the total global methane emission.
Schematic of a typical Biogas
Plant
Anaerobic Digestion: Biogas Production process
MAIN STEPS
• Collection and (pre)treatment
• Producing a slurry with balanced composition (e.g. watercontent, total organic solids. C/N ratio)
• Feeding of reactor with constant rate
• Keeping fermenter at nearly constant temperature of about
33o Centigrade
• Mixing of substrate during fermentation
• Gas collection, purification, utilization (heat and electricity)
• Collection and utilization of fermented slurry e.g as high
value organic fertilizerer
Applications
Power Generation
Thermal Applications
o Irrigation Pumping
o Hot Air Generators
o Village Electrification
o Dryers
o Captive Power (Industries)
o Boilers
o Grid-fed Power from Energy
Plantations on Wastelands
o Thermic Fluid Heaters
o Simultaneous Charcoal and
Power Production
o Furnaces & Kilns
o Ovens
Biogas Plants
Collection
and
pretreatment
Fermentaion
Gas and slurry
utilization
Anaerobic Digestion of Sewage Sludge
Sewage sludge is fermented and used to
cover the energy demand of the waste water
treatment plants. By doing this those plants
need no external energy. The biogas is used
for cogeneration of heat for the digesters an
electricity for the aerobic waste water
purification process (energy for pumping and
aeration of the waste water).
Waste Incinration: Composting
Composting is a traditional technology in agriculture
and gardening. Today there are processes of
treatment of municipal waste which make use of the
heat of composting for drying the solid waste before
separation under investigation. There is no
significant contribution to the enegy supply of
Germany by composting of biomass.
Composting of mixtures of municipal and organic
waste of food industry is implemented in many cities
Technology
• Biomass technology today serves many markets
that were developed with fossil fuels and modestly
reduces their use
• Uses - Industrial process heat and steam, Electrical
power generation, Transportation fuels (ethanol
and biodiesel) and other products.
• Primary focus of the Biomass Program –
development of advanced technologies.
Bio-refinery
• A facility that integrates biomass conversion
processes and equipment to produce fuels,
power, and chemicals from biomass.
• Analogous to today's petroleum refineries
• It is based on the “Sugar Platform“ and the
“Thermochemical Platform“
Modified Waste Vegetable Fat
• Designed for general use in most compression
ignition engines .
• The production of MWVF can be achieved in a
continuous flow additive process.
• It can be modified in various ways to make a
'greener' form of fuel
Environmental Concerns
• Air Pollution
• Soil Deterioration
Air Concerns
• Biomass processing technologies have the potential to
increase emissions of ozone precursors
o Increase in Nox emissions
•Emission of relatively large sized particulate matter
Soil Concerns
• Burning biomass deprives local eco-systems of nutrients
• Production of dedicated energy crops renders land fallow
• Reduced land availability for cattle grazing
•Increased use of pesticides and fertilizers to produce energy
crops contaminate ground and surface water
o Affects fish and wildlife
Environmental Benefits
•Reduction of waste
• Extremely low emission of greenhouse gases compared to
fossil fuels
•Carbon neutral and forms a part of the carbon cycle
• Growing variety of crops increases bio-diversity
Future
The future development will be based on
increasing production of energy crops, optimized
utilization of organic residues and on thermalchemical treatment of organic matter to produce
gaseous and liquid fuels.
There are lot of estimations for future contributions
of biomass to energy supply, they will come to at
least 20 or 30 percent until 2020.