A MAJOR PROJECT PART- I on Development of a 10 Litre Capacity Biodiesel Reactor (Using Commercial NaOH and Methanol) for Rural Applications UNDER THE GUIDANCE OF Prof. PMV Subarao Prof. MKG Babu Department of Mech. Engg. Centre for Ener

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Gasification of Pongamia Shells
P.M.V Subbarao Professor Mechanical
Engineering Department Indian Institute of
Technology, Delhi

A Good integration of Source and Technology ..
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Energy Audit of Sub-Species of Oil Seed
Collections 1ton of Bio-Diesel

• Mass of produce 6.3 tons.
• Mass of Bio Diesel 1 ton.
• Mass of cake 2.15 tons.
• Mass of Shells 3.15 tons.
• Calorific value of Bio-diesel 38 MJ/kg
• Calorific value of cake 19 MJ/kg.
• Calorific value of shells 15 MJ/kg.
• Total Energy value of Bio-diesel 38 GJ
• Total Energy value of Cake 40.8GJ
• Total Energy value of Shells 47.25GJ

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Shells -- Biomass

• Micro Construction basic chains
• Cellulose
• Hemi-cellulose
• Lignin
• All these are long-chain organic molecules with
  C, H, O as main constituent elements
• Cellulose (generic chemical formula (C6H10O5)n)
  is the carbohydrate that makes up the main
  structure of plants.
• It is also referred to as "fibre" and is
  indigestible by humans.
• Cotton fibre is almost pure cellulose.

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Structure of Cellulose
Cellulose is a polymer of glucose units, arranged
in linear formation.
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Structure of Hemicellulose

• Hemicelluloses comprise almost one-third of the
  carbohydrates in woody plant tissue (shell).
• The chemical structure of hemicelluloses consists
  of long chains of a variety of pentoses, hexoses,
  and their corresponding uronic acids.

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Structure of lignin
Lignin is an organic substance binding the cells,
fibres and vessels which constitute wood.
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Typical Composition of Shelly Wood
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Thermal Processing of Woody Biomass

• On heating, any solid fuel undergoes the
  following processes
• Drying (lt150oC)
• Pyrolysis (200-700oC)
• Flaming Combustion
• Glowing Combustion
• Final products CO2, H2O (complete
  combustion)
• In short supply of oxygen, Combustion is
  incomplete, and products are CO, H2
  Combustible gases gaseous fuel. (If
  temperatures are high enough)
• Biomass Gasification is a form of deliberate
  incomplete combustion

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Thermal Degradation of Pongamia Shell
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Rate of Thermal Degradation of Pongamia Shell
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Biomass Gasification
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Gasification of Shells

• Shells are heated to dry and pyrolyse
• Just enough oxygen provided to consume a part of
  volatiles and char, yielding CO2 and H2O
  Oxidation process.
• These products of combustion pass over the hot
  char (Carbon) to get reduced to CO and H2
  Reduction process, water gas reaction
• Additional water/steam can enhance H2 content of
  gas
• Gas is cooled and cleaned, if needed by end use

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Gas Composition
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Biomass Gasifier Types
Downdraught Gasifier
Cross-draught Gasifier
Updraught Gasifier
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Biomass Gasifier Types

• Updraught Gasifier
• Biomass flows downwards, and gas/air flow upwards
• Simple construction
• Tar content in gas high
• Most suited for thermal applications
• Downdraught Gasifier
• Biomass moves downwards, so do air/gas
• Gas passes over high temperature zones low tar
• Most suited for engine/gas turbine applications
• Cross-draught Gasifier
• Biomass moves downwards, air/gas flow
  horizontally
• Suitable for high capacity systems
• Tar content is high

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Shell Gasifier
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Stoichiometry of Gasification of Shells

• Oxidation Generation of required thermal energy.
• C O2 CO2 Thermal Energy
• H2 O2 H2O Thermal Energy
• Reduction Generation Fuel gases.
• Bouduard reaction CO2 C 2 CO - Thermal
  Energy
• Water-gas reaction C H2O CO H2 - Thermal
  Energy
• Shift reaction CO2 H2 CO H2O - Thermal
  Energy
• Methane production reaction C 2H2 CH4
  Thermal Energy
• How to suppy Optimum amount of oxygen for
  gasification of shells!!!

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Maximizing Energy Content of in Producer Gas

• Highest heating value for the gas is achieved
  when production of Hydrogen and CO is high.
• The heating value depends on the design of the
  gasifier and on the characteristics of the fuel
  provided to the gasifier.
• Minimization of the heat losses from the gasifier
  is important in order to achieve a high heating
  value of the gas.
• The moisture content and the size distribution of
  shells are two of the most important fuel
  characteristics.
• Both excess and deficiency of air lead to a
  decrease in the heating value of the mixture (per
  unit volume).

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Analysis of Shells of Pongamia Fruits
Entity Pongamia Shell () Wood ()
Ash 4.09 1-3
Volatile matter 66.99 70-80
Fixed carbon 18.95 15-20
Moisture content of Pongamia Shells 10.6
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Ultimate Analysis of Shells
Entity Pongamia Shell () Wood ()
Ash 4.09 1-3
Carbon 44.3 44-52
Hydrogen 7.45 5-7
Nitrogen 1.73 0.5-0.9
Sulfur 0.3 Negligible
Oxygen 42.13 40-48
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Gasifier at IIT Delhi
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Gasifier with I.C. Engine
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Gas Composition
Wood Gas
Composition CO2 CO H2 N2 CH4
Gas Sample () 11.46 17.03 14.95 55.55 1.02
Shell Gas
Gas CO2 CO H2 N2 CH4
Sample () 9.47 9.71 5.29 74.56 0.96
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Performance Analysis of Gasifier

• Energy content of gas produced per heating value
  of one unit of shells.
• Depends on
• Amount of Hydrogen produced per unit mass of
  shells.
• Amount of CO produced per unit mass of shells.
• Measure flow rate of gas and composition of gas.
• Maximize specific gas energy.

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Element Composition
Carbon 44.3
Hydrogen 7.45
Oxygen 42.13
Nitrogen 1.73
n(CxHyOzNk ) n F (O23.76N2) ? x1CO2 x2CO
x3H2 x4N2 x5CH4 x6O2
Biomass Producer gas composition () Producer gas composition () Producer gas composition () Producer gas composition () Producer gas composition () Calorific value
H2 CO CH4 CO2 N2 (MJ/kg)
Shell 5.29 9.71 0.96 9.47 74.56 14.42
Wood 14.95 17.03 1.04 11.46 55.55 16.37
Chemical reaction equation for shells
gasification becomes n (C3.69H7.45O2.63N0.12)
n F (O23.76N2) ? x1CO2 x2CO x3H2 x4N2
x5CH4 x6O2
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• Operating parameters of gasifier
• Gas flow rate 9.51 g/s

• Air-Fuel ratio 4.97

• Calorific value of producer gas 2.29 MJ/m3

• Mass of producer gas generated per kg of shell
  5.14 kg of gas/kg of shell

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Operating parameters of wood and Pongamia shells
gasifications
Entity Pongamia Shells Wood
gas flow rate (g/s) 9.51 9.62
N 5.46 7.30
F 3.62 2.01
(A/F)m 4.97 2.77
CVg (MJ/m3) 2.29 4.48
mg (kg of gas/kg fuel) 5.14 3.54
MWg (kg/kmol) 28.02 25.82
? (kg/m3) 1.15 1.06
E (MJ/kg fuel) 10.27 15.01
Cth 0.65 0.84
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Setting up of Flow rates of Shells AirA
Critical Parameter for Performance of Gasifier.
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Optimal Sizing of Conical Grate
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Optimization of Shell flow Rate for Better Gas
Quality
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Optimization of Shell flow Rate for Better
Conversion
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Internal Generation of Energy Credits