BIOMASS

1
oldest kind
BIOMASS
of
energy use
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INTRODUCTION
? Wood was once our main fuel. We burned it
to heat our homes and cook our food. Wood still
provides a small percentage of the energy we use,
but its importance as an energy source is
dwindling.
? Sugar cane is grown in some areas, and can
be fermented to make alcohol, which can be burned
to generate power. Alternatively, the cane can be
crushed and the pulp (called "bagasse") can be
burned, to make steam to drive turbines. ?
Other solid wastes, can be burned to provide
heat, or used to make steam for a power station.
? "Bioconversion" uses plant and animal
wastes to produce fuels such as methanol, natural
gas, and oil.
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DEFINITION

• Biomass is produced from organic materials,
  either directly from plants or indirectly from
  industrial, commercial, domestic or agricultural
  products. It is often called 'bioenergy' or
  'biofuels'. It doesn't include fossil fuels,
  which have taken
• millions of years to be
• created.

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CATEGORIES
? Woody biomass includes forest products,
untreated wood products, energy crops and short
rotation coppice (SRC), which are quick-growing
trees like willow.
? Non-woody biomass includes animal waste,
industrial and biodegradable municipal products
from food processing and high energy crops.
Examples are rape, sugar cane, maize.
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SOURCES OF BIOMASS
AGRICULTURAL WASTE
PLANTS
INDUSTRIAL WASTE
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PLANTS
Plants are the most common source of
biomass. They have been used in the form of wood,
peat and straw for thousands of years.
Plants can either be specially grown for energy
production, or they can be harvested from the
natural environment. Plantations tend to
use breeds of plant that are to produce a lot of
biomass quickly in a sustainable fashion.These
could be trees (e.g. Pine or Eucalyptus) or other
high growth rate plants (such as sugar cane,
maize or soybean).
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AGRICULTURAL WASTE
Waste from agriculture includes the
portions of crop plants discarded (including
forestry waste), whether damaged or surplus
supplies, and animal dung. When wood is used as a
fuel, there are low sulphur and nitrogen oxide
emissions, but there is concern about the
by-products of using pesticide treated materials
(as with straw).
There is some potential to use more wood waste,
especially residues arising from forestry
operations. This could be collected, dried and
used by rural industry. If the residues produced
by sugar cane, forestry, and grain manufacture,
plus all animal dung were converted to energy
this would supply 30 of the world's energy needs.
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INDUSTRIAL WASTE
Other useful waste products include waste from
food processing and fluff from the cotton and
textiles industry.
Industrial waste that contains biomass may
be used to produce energy. For example, the
sludge left after alcohol is made (known as
vinasse) if this is processed it can produce
flamable gas.
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Methods of generating energy
from biomass
The methods of generating energy can be split
into two different groups there are the dry
processes and the wet processes The dry
processes are Combustion
Pyrolysis The wet processes are Anaerobic
digestion
Gasification
Fermentation
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COMBUSTION
One problem with this method is its very low
efficiency. With an open fire most of the heat is
wasted and is not used to cook or whatever.
The most obvious way of extracting energy from
biomass, the technology of direct combustion is
well understood, straightforward and commercially
available.Combustion systems come in a wide range
of shapes and sizes burning virtually any kind of
fuel, from chicken manure and straw bales to tree
trunks, municipal refuse and scrap tyres.
Some of the ways in which heat from burning
wastes is currently used include space and water
heating, industrial processing and electricity
generation.
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PYROLYSIS
A wide range of energy-rich fuels can be produced
by roasting dry woody matter like straw and
woodchips. The process has been used for
centuries to produce charcoal. The material is
pulverised or shredded then fed into a reactor
vessel and heated in the absence of air.
Pyrolysis can also be carried out in the presence
of a small quantity of oxygen ('gasification'),
water('steam gasification') or hydrogen
('hydrogenation'). One of the most useful
products is methane, a suitable fuel for
electricity generation using high-efficiency gas
turbines.
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ANAEROBIC DIGESTION
Biogas is produced when wet sewage sludge,
animal dung or green plants are allowed to
decompose in a sealed tank under anaerobic
(oxygen-free) conditions. Feedstocks like wood
shavings, straw and refuse may be used, but
digestion takes much longer.
Each kilogram of organic material (dry
weight) can be expected to yield 450-500 litres
of biogas.The residue left after digestion is a
potentially valuable fertilizer or compost.
Fermentation Ethanol (ethyl alcohol) is produced
by the fermentation of sugar solution by natural
yeasts.
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GASIFICATION
This process, usually using wood produces a
flammable gas mixture of hydrogen, carbon
monoxide, methane and other non flammable by
products.
This is done by partially burning and partially
heating the biomass (using the heat from the
limited burning) in the presence of charcoal (a
natural by-product of burning biomass).
The gas can be used instead of petrol and reduces
the power output of the car by 40. It is also
possible that in the future this fuel could be a
major source of energy for power stations.
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FERMENTATION
If the biomass used is (or can be converted into)
mostly sugar, then yeast can be added. The
fermentation that follows produces alcohol which
is a very high energy fuel that makes it very
practical for use in cars. This has been tried
succesfully in Brasil.
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CONCLUSIONS
In addition to the many environmental benefits,
biomass offers many economic and energy security
benefits. By growing our fuels at home, we reduce
the need to import oil and reduce our exposure to
disruptions in that supply. Farmers and rural
areas gain a valuable new outlet for their
products. Biomass already supports 66,000 jobs in
the United States if the DOE's (Department of
Energy) goal is realized, the industry would
support three times as many jobs.
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THE ADVANTAGES OF BIOMASS
? Biomass is very abundant. It can be found
on every square meter of the earth as seaweed,
trees or dung ? It is easy to convert to a
high energy portable fuel such as alcohol or
gas ? It is cheap in contrast to the other
energy sources ? Biomass production can
often mean the restauration of waste land (e.g.
deforested areas) ? It may also use areas of
unused agricultural land and provide jobs in
rural communities ? If it is produced on a
renewable basis using biomass energy does not
result in a net carbon dioxide increase as plants
absorb it when they grow ? It is very low in
sulphur reducing the production of acid rain.
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THE DISADVANTAGES OF BIOMASS
? Expensive to collect, harvest and store raw
materials ? We burn the fuel, so it makes
greenhouse gases ? Some waste materials are
not available all year round ? Extra costs
of installing technology to process and recycle
wastes ? Large scale crop production will
use vast areas of land and water,
representing major problems.
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Vasile Paula
Made by

Drimbarean Ioana
Mr. Schnabel Dieter
Coordinator