Conversion of Biomass Energy into useful energy'

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Conversion of Biomass Energy into useful energy.

• By the method how it is utilized.
• Direct (heat energy obtained by burning wood,
  agricultural waste or Dung cake etc. as in
  stove (Chulo)
• Indirect (first converted into a convenient or
  suitable fuel in the form of solid, liquid or
  gases)

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Conversion of Biomass Energy into useful
energy.contd..

• By the process of energy conversion
• Thermochemical (Combustion, Gasification and
  Methanol Production)
• Biochemical (Anaerobic digestion and Ethanol
  Production)
• Chemical (Biodiesel and lubricants.)

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Biomass Energy Technology
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Possible Routes for treatment and conversion of
biomass energy
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Selection of Conversion Technology

• The selection of biomass conversion technology
  is govern by following factors.
• The feedstock available
• The end application
• The cost

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Main Biomass Types

• FuelWood
• Agricultural Residues
• Energy Crops

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Resource assessment

• How much is available ?
• How reliable is the supply ?
• Sustainability at the intended rate ?
• Cost of collections (transportation etc.)
• Benefit by utilizing Waste (environment impact)
• Social and adaptability factor that influence the
  availability and suitability

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Agricultural Residues

• Crop residues (Rice Straw, Wheat straw
  Cotton stalk etc.).
• Agro processing residues (Rice husk, Maize
  cobs etc.)
• Animal Dung (also considered as agricultural
  residue)

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The availability of Agricultural Residues

• A healthy animal produce 4-5 times their weight
  (dry dung) each year.
• Most cereal crops gives between 1.5-2.5 tonnes of
  straws for every tonne of grain.
• Dung crop residues are major resources which
  constituting the largest biomass production at
  the utilized level.
• Rough estimation of agricultural residues
  production can be derived using national
  livestock Crop production statistics.

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Factors to be considered while estimating Energy
Potential of Agricultural Residues.

• Climate variation
• Average annual residue yield
• Recoverable fraction
• Environmentally permissible fraction
• Competing other uses
• Losses

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Grouping of Agricultural Residues

• Woody crop residues (Coconut shell, Jute sticks
  etc)
• Cereal residues (Rice wheat straw, Maize stalks
  etc.)
• Green crop residues (Ground nut straw, Soybean
  tops).
• Crop processing residues (Rice husk, ground nut
  shell etc).
• Animal dung.

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Residues to Crop Ratios for some selected crops.
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Residues to Crop Ratios for some selected crops.
(Contd.)
Source Renewable Energy Technologies Their
Application in Developing Countries (L.A.
Krisotferson and V. Bokalders) Intermediate
Technology publication-1991. The Power Guide
(Wim Hulcher and Peter Fraenkel) Intermediate
Technology publication-1994
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Dung production from animals
Source Renewable Energy Technologies Their
Application in Developing Countries (L.A.
Krisotferson and V. Bokalders) Intermediate
Technology publication-1991. The Power Guide
(Wim Hulcher and Peter Fraenkel) Intermediate
Technology publication-1994
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Calorific value of some selected Agricultural
residues
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Calorific value of some selected Agricultural
residues (Contd.)
Source Renewable Energy Technologies Their
Application in Developing Countries (L.A.
Krisotferson and V. Bokalders) Intermediate
Technology publication-1991. The Power Guide
(Wim Hulcher and Peter Fraenkel) Intermediate
Technology publication-1994
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Gross calorific value of fresh dung
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Biomass Preparation

• The acceptability of fuel depend on
• Its performance as a fuel, which depends upon its
  combustion characteristics
• Its ability to harvested, transported and stored
  economically

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Biomass Preparation (Contd.)

• Characteristics of agricultural residues
• High moisture content (Reduce combustion
  efficiency, producing ignition difficulties)
• Contamination of foreign particles (Stone, Dust
  etc.)
• Large in size (Difficult to facilitate automatic
  handling)
• Often have fluffy (Low bulk and low densities).

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Biomass Preparation (Contd.)

• Pretreatment to make it suitable to use.
• Drying (removal / reducing of moisture)
• Size reduction (Shredder, chipper, grinder)
• Densification (Briquettes)

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Combustion

• Thermo-chemical process of converting biomass
  energy into heat energy by burning the biomass in
  present of air i.e. oxygen.
• Residential Purpose
• Industrial Purpose

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A Typical Boiler - for Industrial Purposes
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Pyrolysis

• Thermo chemical process where organic material
  partially combusted to produce secondary fuels
  and chemical product
• The process of Pyrolysis gives three groups of
  products.
• a solid (Known as char or charcoal)
• a liquid (known as pyroligeneous acid or oil
  which content a mixture of chemicals)
• a mixture of gases (CO, H2, N2)

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Pyrolysis Plant Typical Example
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Pyrolysis (Contd.)

• The ratio of products varies with the chemical
  composition of the biomass and the operating
  conditions.
• A typical Example
• 1- tonne of hardwood produced
• 350kg Charcoal
• 450kg pyrogeneous acid (20-34MJ/kg)
• 75kg tar and 60m3 gas.(3.5-8.9MJ/m3)

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Pyrolysis (Contd.)
Chemical from Pyroligenious acid and their
potential applications
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Pyrolysis (Contd.)
Before cheap fossil fuel it was extensively used
in chemical industries

• Main Present applications are
• to produce charcoal (with other byproduct not
  being used)
• or, to complete gasification (to produce tar
  etc.)
• or, to provide energy.

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Gasification

• Thermochemical process that converts biomass
  into a combustible gas called Producer gas.
• Producer gas contains
• Carbon monoxide,
• Hydrogen,
• Water vapor,
• Carbon dioxide,
• Tar vapor and ash particles

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Gasification

• Fuel for Gasifier
• A wide range of biomass materials can be used
  for Gasification
• A Typical Example 1 kg of Dried biomass gives
• 3-3.6 kWh heat Energy
• or,
• 0.7-0.9 kWh electricity plus 1.4 kWh heat.

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Gasification (Contd.)

• Operation system of Gasifier
• Complete gasification takes place in four stages
• Drying of feedstock (1200C)
• Pyrolysis (2006000C)
• Combustion (90012000C)
• Reduction (9006000C)

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Gasification (Contd.)

• Typical the volumetric composition of biomass
  based producer gas are as follow
• CO ? 20 22
• H2 ? 15 18
• CH4? 2 4
• CO2 ? 9 11
• N2 ? 50 54

Tar and particulate materials
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Gasification (Contd.)

• Use of Gasifier gas
• Variety of thermal application including
• Cooking
• Drying
• Water heating
• Steam generation
• Mechanical / Electrical power generation
• Fuel for Internal combustion engine

The Heating value of gases rages from 4000
5000 kJ/kg
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Gasification (Contd.)

• Types of Gasifiers
• 1. Fixed bed Gassifier
• Up draft
• Down draft
• Cross draft
• 2. Fluidized bed Gassifier

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Schematic View of Up draft Gasifier
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Schematic View of Down draught Gasifier
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Schematic View of Cross draught Gasifier
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Schematic View of Fluidized bed Gassifier
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Fermentation

• Naturally occurring biochemical process concerned
  to micro-organism.
• Micro-organism are invisible bacteria of
  different types
• These Bacteria can be divided into two major
  groups.
• Aerobic (which grows in the presence of oxygen)
  and
• Anaerobic (Which grow in absence of gaseous
  oxygen).

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Fermentation (Contd..)

• Aerobic Fermentation
• Aerobic Fermentation (Ethanol Production)
• Fermentation takes place in the presence of air.
• Ethanol feedstocks
• Sugars, from sugar cane, sorghum, molasses,
  fruits and whey (residue from cheese production)
• Starch, from grains (rice, maize etc.) cassava,
  potato
• Cellulose, from wood agricultural residues.

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Fermentation (Contd..)

• Ethanol production processes.
• Feedstock collection
• Pretreatment to yield sugar
• Fermentation
• Distillation
• Waste treatment (Anaerobic fermentation to
  methane)

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Ethanol yields from various selected crops
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Anaerobic digestion

• Biochemical process in which particular kinds of
  bacteria digest biomass in an oxygen-free
  environment.
• Several different types of bacteria work together
  to break down complex organic wastes in stages,
  finally resulting in the production of Biogas."

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Anaerobic digestion (Contd..)

• Biogas Production
• Biogas is mixture of methane (50 - 70) and
  carbon dioxide with traces of hydrogen sulphide
  and water
• Combustible gas
• (calorific value 16 - 20 MJ/m³).

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Biogas Production Process

• Mixing of organic matter (such as animal dung)
  with some water
• Placed this mixture (Slurry) in a leak proof
  container (called a digester) and left to
  ferment.
• After several days at suitable temperatures,
  sufficient methane will have formed to make a
  combustible gas.

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Biogas Feedstock

• Any organic material can be used
• Production rate depend on type of feed stock
  used.
• Woody materials such as straw are very difficult
  to digest
• Animal dung digests readily
• Pretreatment may be needed for some materials (
  Chopping etc.)

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Digester Designs

• There are three well-known designs that have
  originated in developing country
• The floating drum type (or Indian) digester
• The fixed dome (or Chinese) digester
• The flexible bag (or Taiwanese) digester

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The floating drum type (or Indian) digester
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The fixed dome (or Chinese) digester
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The flexible bag (or Taiwanese) digester
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Liquid Fuel from Biomass

• Several possibilities for the production of
  liquid fuel from Biomass
• Ethanol The easiest route is to use a
  sugar-bearing feedstock (like sugarcane) for
  fermentation to ethanol.
• Methanol By thermochemical coversion Process
  (wood alcohol)(Gasification under conditions of
  high pressure and temperature).

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Liquid Fuel from Biomass (Contd.)

• Biodiesel (Vegetable Oil)
• Chemical conversion process of extracting oil
  from the seedy feedstock.
• The two main processes are
• Mechanical press extraction
• Solvent extraction

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Organic Waste

• Waste from Agroprocessing Industries.
• Waste from households, small companies,
  institutions and markets
• Industrial Waste
• Amount increases considerably with
  industrialisation and urbanisation

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Utilization of Organic Waste

• All these Waste can be groped as Solid or Liquid
  
• Solid Waste
• Landfill Gas is Produced from Solid Waste
• The same anaerobic digestion process that
  produces biogas in animal manure and wastewater
  treatment digesters occurs naturally underground
  in landfills

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Utilization of Organic Waste (Contd.)

• Liquid Waste
• Many Industries produces large volume of liquid
  waste which contains solution of organic
  materials
• These waste water can be treated anaerogbically
  to used a useful energy.
• Upflow Anaerobic Sludge Blanket (UASB) is the
  most widely used technology for liquid effluent.

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Schematic diagram of an USAB reactor
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THE END