Biomass gasification is a mature technology pathway that uses a controlled process involving heat, steam, and oxygen to convert biomass to hydrogen and other products, without combustion.

1. BIOMASS
GASIFICATION

2. Carbon cycle

3. CONVERSION ROOT OF BIOMASS FUELS
Thermochemical conversion Biochemical conversion
Combustion Gasification Pyrolysis
Digestion Fermentation
Extraction
Steam Gas Gas Oil Charcoal Biogas
Steam Methanol / Upgrading Upgrading Distillation Esterification
Turbine Gas turbine/cc hydrogen Combustion
Engine synthesis gasification/
engine, etc
Fuel cell
Hydrogen/ Diesel Ethanol Bio-diesel
methanol
Heat Electricity Liquid fuels

4. Types
Stochiometric air supply
• Combustion (Excess)
 Gasification (Controlled/limited)
 Pyrolysis (Absence)
Combustion
• Excess oxygen
• Boilers
• Furnaces
• Cooking stoves

5. Improved chulhas

6. Boiler Furnace

7. Agricultural residues Agro-Industrial residues Forest residues
Pearl millet stalks
Sorghum stalks
Maize stalks
Millet straws
Sugarcane trash
Coconut shells, fibre & pith
Banana plant waste
Cotton stalk
Pulses-straw & stalks
Oil seed straw
Tobacco straw
Jute & Mesta sticks
Castor stalks
Mustard stalks
Paddy straw
Rice husk
Bagasse
De-oiled cakes
Groundnut shells
Castor/oilseed shells
Tea/coffee wastes
Cotton ginning waste
Cashew nut shell
Coconut shell
Coconut fibre
Coconut pith
Deadwood from
existing forests
Wood from specially
grown plantations
Saw mill wastes
Pulp wood wastes
Road side bushes
Wood from
wastelands
BIOMASS SUITABLE FOR POWER GENERATION

8. BIOMASS PRODUCTION IN INDIA
Source of Biomass Estimated Quantity(MT )
Agriculture / agro-industrial 439.4
Sugarcane tops and trash 84.0
Roadside growths 10.7
Forest residues 157.2
Growth on Wastelands 27.1
Agro forestry waste 9.1
Dung live stock 267.7
Poultry droppings 4.8
Total 1000

9. RENEWABLE ENERGY - POTENTIALAND UTILIZATION
(POWER GENERATION)
Sources/Systems Potential Harnessed (MW)
Biomass power 19,500 302.50
Cogeneration 10,000 692.00
Gasifiers 146.00
Wind power 45,000 7850.00
Small hydro power 15,000 2015.00
Waste to energy 1,700 560.00
Solar PV 2.75
Total 7% of total electricity installations in
India amounting to MW
11,150.00

10. CHEMICAL CHARACTERISTICS
PROXIMATE ANALYSIS
• Moisture content
• Volatiles
• Ash content
• Fixed carbon
ULTIMATE ANALYSIS
• Carbon
• Hydrogen
• Oxygen
• Sulphur
• Nitrogen

11. BIOMASS CHARACTERISTICS
• Moisture Content : < 15 %
• Calorific value : > 3000 kcal /kg
• Size : 10 -80 mm (0.5 - 3 in)
• Ash : < 10%
• Carbon Mono Oxide : 15 -20 %
• Hydrogen : 15 - 20 %
• Methane : 2 -4 %
• Carbon di Oxide : 5 - 10 %
• Nitrogen : 45 - 55 %
PRODUCER GAS COMPOSITION

12. MOISTURE CONTENT
 High moisture content : reduce temperature poor
quality gas
 Best gas : moisture content 15 %
 Lower moisture level : Hydrogen decreases
 Higher moisture level : CO decreases
 Higher moisture : problem in smooth operation

13. TEMPERATURE
 Higher temperature account for higher carbon
monoxide and lower methane
 The hydrogen content increases up to a temperature of
1100°F and starts decreasing
 Higher temperature around 1500°F is considered more
suitable for gasification

14. PRESSURE
 The gasifier pressure has not effect on the gas quality,
or the gasification efficiency
 However, the higher pressure is known to increase the
gasification rate and the gasifier capacity

15. FUEL SIZE AND SHAPE
 Size and shape of the fuel plays an important role for
smooth operation
 Too small : increase the pressure drop which leads to
material flow problems
 The bigger fuel size : flow problem in the throat un-
pyrolysed biomass
 Appropriate fuel size : selected with respect the
reactor type

16. • Biomass gasification is a thermo-chemical process by
which, biomass containing carbon, hydrogen and
oxygen is reacted with restricted amount of air/
oxygen and/or steam to yield a mixture of combustible
gases consisting of carbon monoxide, hydrogen and
traces of methane. This mixture is called producer gas
• Gasification accomplished in air sealed chamber -
slight suction or pressure relative to ambient pressure
Heat + biomass = gas + pyrolytic oils + char + ash +
steam
BIOMASS GASIFICATION

17. GASIFICATION
• Gasification is a partial oxidation process whereby a
carbon source such as coal, natural gas or biomass, is
broken down into carbon monoxide (CO) and Hydrogen
(H2) plus carbon dioxide (CO2) and possibly hydrocarbon
molecules such as methane (CH4)
• This mix of gas is known as producer gas and the precise
characteristics of the gas will depend on the gasification
parameters such as temperature and also the oxidizer used
• The oxidizer may be air, in which case the producer gas
will also contain Nitrogen (N2), or steam or oxygen

18. GASIFIER
• Gasifier is an equipment which can gasify a variety of
biomass such as wood waste, agricultural wastes like
stalks and roots of various crops, maize cobs, etc.
• The gasifier is essentially a chemical processes take
place. Biomass gets dried, heated, pyrolyzed, partially
oxidized and reduced, as it flows through it.
• The gas produced in the gasifier is a clean burning
fuel having calorific value of about 950 to 1200
Kcal/m3.
• Hydrogen(18 - 20 %)and carbon - monoxide (18 -
24%) are the main constituents of the gas.
• The advantages of a gasifier are very easy to operate,
maintain, sturdy in construction and reliable in
operation

19. 1. Grate
2. Throat
3. Air nozzle/air distribution system
4. Ash removal system/ash removal port
5. Gas outlet
6. Ignition port
7. Biomass feeding port
8. Hopper
COMPONENTS OF THE GASIFIER

20. • The significant factor that influences the process of gasification is
the equivalence ratio, Φ which is defined as
Air or oxygen in process
• Φ = ---------------------------------------------------------------------
Stoichiometric air needed for complete combustion
It can be noted that it requires 6.26 kg of air to burn 1 kg of dry
wood,
(144/23 = 6.26)
COMBUSTION
C H1.4 O0.6 + 1.05(O2 + 3.76 N2) CO2 + 0.7 H2O + 3.95 N2
Mass : 23 144.1 44 12.6 110.5
GASIFICATION
C H1.4O0.6 + 0.35 O2 0.4 CO + 0.6 H2 + 0.4 CO2 + 0.1 H2O + 0.2 C
EQUIVALENCE RATIO

21.  The equivalence ratio increases the carbon monoxide
level of producer gas increases (after passing through a
maximum at equivalence ratio of 25 % starts decreasing
and the carbon dioxide starts increasing)
 The methane content of producer gas decreases with
increasing Φ up to 0.25

22. Gasifier: A reactor which converts solid fuels in to gaseous
fuel through thermo-chemical process under
controlled condition of air
Producer gas: It is a mixture of gases produced when materials
like wood, charcoal, coal, lignite or crop residue
are burnt under controlled condition of air
Pyrolysis: It is the process wherein heat is used to
breakdown biomass in the absence of air to yield
charcoal, wood-oils, tars and gases
Pyrolysis zone: In this zone, the solid material starts
disintegrating at 250°C to produce char as well as
condensable and non-condensable gases
TERMINOLOGIES PERTAINING TO
GASIFICATION

23. Oxidation zone: In this zone, air is introduced for oxidation of
biomass. Apart from heat generation, all
condensable & organic products of pyrolysis get
converted and oxidized
Reduction zone: In this zone, sensible heat of gases and charcoal
is absorbed in endothermic reactions between
water, CO2 and carbon in the charcoal
Turn down ratio: Turn down ratio of a gasifier is the ratio of
maximum to minimum gas generation rates at
which it can be reasonably and efficiently operated
without drop in quality of gas
Specific gasification rate: Specific gasification rate is the quantity
of biomass consumed per unit time and unit cross-
sectional area of gasifier

24. FACTORS INFLUENCING THE PERFORMANCE OF
GASIFIER
Fuel Qualities that affect gasifier performance are
• Energy content
• Fuel grain or pellet size and uniformity
• Bulk weight or calorie value per volume
• Tar content
• Moisture content
• Dust tendency
• Ash and slag tendency
• Reaction response
• Equivalence ratio

25. THERMO-CHEMICAL REACTIONS OCCURRING IN
GASIFICATION
COMBUSTION/OXIDATION ZONE
• combustion reaction - exothermic reaction -
theoretical oxidation temperature - 14500C
C + O2 = CO2 (+ 393 MJ/kg mole)
2H2 + O2 = 2H2O (- 242 MJ/kg mole)

26. SEQUENCE OF REACTIONS IN A
DOWNDRAFT GASIFIER
Air +
Water
Fuel
Drying Zone 65°C
Tar formation,
steam formation 230°C
oxidation zone + 1100°C
H2O (Moisture  H2O
(Steam)
CxHyOz  Volatile gas and
liquid
C + O2 = CO2 + 406 KJ/g.
mols
Primary reduction zone 825°C
Secondary reduction zone
Solid residue and gas 540°C
C +H2O = CO + H2 + 131.4 kJ / g. mole
C+2H2O= CO2+2H2 +78.75 kJ /g. mole
C + CO2 = 2CO – 172.6 kJ/g. mole
C + CO2 = 2CO – 172.6 kJ/g. mole
CO2 + H2 = CO + H2O – 412 kJ/g. mole
2 CO = CO2 + C

27. 4 O2 - - - - 16.15 -
5 CH4 08.17 04.94 04.75 04.75 12.40 00.75
6 C2H6 00.43 00.26 00.25 00.25 12.30 -
Sl.No Gases Wood Corn
cob
Barley
straw
Tree
pruning
Rice
straw
Peat
1 CO2 09.70 10.90 13.70 13.70 08.40 15.30
2 CO 23.90 20.90 18.80 18.80 15.30 16.15
3 H2 16.30 13.40 16.40 16.40 26.10 12.30
GAS COMPOSITION OF VARIOUS BIOMASS
MATERIALS ON GASIFICATION (% by Volume)

28. PROCESS OF GASIFICATION

29. CONVERSION OF BIOMASS INTO PRODUCER GAS

30. VOLUMETRIC COMPOSISTION OF PRODUCER GAS

31. PRODUCER GAS COMPOSITION
Gas MJ % Contribution
CO 12.6 20.5 [2.58]
Hydrogen 12.8 17 [2.18]
Methane 39.8 2 [0.79]
Ethane 70.4 0.1 [0.07]
Ethylene 64 0.1 [0.06]
Nitrogen 49.2 [0]
CO2 11.2 [0]
Heating Value 5.68

32. BIOMASS SUITABLE FOR GASIFICATION
Biomass Fuels
• Fuel wood
• Agriculture stalk
• Coconut shells
• Briquettes of several residues
• Mustard stalk
• Cashew-nut shells

33. GASIFIER

34. DESIGN OF DOWN DRAFT GASIFIER
• Diameter of the throat
• Diameter of tube
• Diameter of air inlets (tuyers)
• Velocity of entering air

35. (I) Fuel consumption (q) q =
Where:
q = fuel consumption, kg/h
P = engine output, kW
= overall efficiency, i.e.(Gasification efficiency X Engine
combustion efficiency)
Hw = lower heating value of biomass, kJ/kg
(II) Quantity of gas produced, Q =
Where:
= gasification efficiency
q = fuel consumption, kg/h
Hw & Hg = lower calorific values of biomass and producer gas in
kJ/kg and kJ/Nm3
(III) Volume of reactor, V =
Where:
t = time of operation
Sp = piled density of biomass, kg/m3
w
tot H
P



3600
o

g
w
c
H
H
q


c

p
S
q
t
DETERMINATION OF VARIOUS PARAMETERS OF
THROATLESS GASIFIER

36. Rate of fuel consumption, kg/h
(IV) Area required, A = -----------------------------------------
Specific gasification rate, kg/hm2
Diameter of the reactor, D =
(V) Height of the reactor, h =
4
/

A
2
4
D
V


DETERMINATION OF VARIOUS PARAMETERS OF
THROATLESS GASIFIER

37. Parameters, which influences the grate design, are:
(i) Rate of ash removal
(ii) Superficial gas velocity and flow field
(iii) Size distribution of the char
(iv) Bulk density of the char
(v) Construction and cost maintenance
The area of grate may be calculated by following formula:
Where,
A = grate area, m2
q = biomass consumption, kg/h
SGR = specific gasification rate of biomass, kg/h-m2
The diameter of grate:
A
q
SGR

D
A

4

Type of throat Average capacity (SGR),
kg/h-m2
No-throat-design 100 - 275
Single throat 200 - 1200
Double throat 600 - 4200
DESIGN OF GRATE

38. Thermal Gasifier

39. Wood Based Down Draft Gasifier

40. Twin Drum Gasifier

41. Bagasse Based Gasifier

42. Fluidised Bed
Gasifier

43. CREMATORIUM,
KARAIKAL, PONDICHERRY

44. ;

45. 100 kWth T V S SRICHAKRA, MADURAI
BIOMASS GASIFIER – COCONUT SHELL

46. DOSA BURNER – KNIFE TYPE
T V S SRICHAKRA, MADURAI

47. SAMBAR & RASAM PREPARATION
Circular Burner
T V S SRICHAKRA, MADURAI

49. UTILIZATION OF PRODUCER GAS

53. PRODUCER GAS
THERMAL AND POWER OPTIONS

54. Bagavathy Biopower Ltd, Mettupalayam, Coimbatore
MAKE : Cummins supplied by M/s Powerica, Bangalore
(modified as 100 % producer gas engine)
CAPACITY FOR NATURAL GAS : 144 kW derated to 110 kwe
ALTERNATOR : 180 kVA
POWER FACTOR : 0.8

55. Biomass Drying Arrangement
using exhaust gas of the engine
at
M/s Bagavathy Biopower Ltd,
Mettupalayam, Coimbatore
District
Capacity
1.6 tons at a time
Duration
7 hours
Gas Temperature
350 – 400C

56. GASIFIERS- ELECTRICAL (9 KW)
Odanthurai Panchayat, Coimbatore District

57. M/s Arasi Hi- Tech Biopower Ltd., Sultanpet, Coimbatore District
MAKE : Cummins supplied by M/s Powerica, Bangalore
TYPE : GTA 1710 G ( Natural Gas Engine ) ( No of Engines : 5 )
modified as 100 % producer gas engine
RATING COST : 256 kW
ALTERNATOR : 320 kVA
POWER FACTOR : 0.8

58. This gasifier can operate with wide
variety of fuels compared to an up
draft or a down draft gasifier
High gas exit temperature, higher
gas velocity at the gas exit
Poor CO2 reduction are certain
characteristics of this type of gasifier
This type of gasifier has been used
for gasification of coal
Reaction zones in a cross draft gasifier
CROSS DRAFT GASIFIER

59. FLUIDIZED BED GASIFICATION
Definition
A fluidization bed is a chamber with a perforated floor
having pressurized air flowing vertically where a particle
medium usually sand, is contained. The pressurized and
flowing air helps the medium allowing it to act as a fluid

60. PRINCIPLE OF FLUIDIZED BED
GASIFICATION
• Can use most fuels (wood,
peat and coal) including
agriculture waste such as
straw, corn stover and
manure
• Has potential to use
municipal waste such as
garbage
• Quicker in response
• Has shorter start time
• Complex design
• Lends itself to complete
combustion applications
which would allow it to use
liquid wastes such as used
engine oil, non-recyclable
plastics & old shoes, garbage
for generation of heat

61. Fluidized bed gasifier is a homogeneous reactor bed of some inert sand material. The
fuel is introduced in the inert bed material and air at the bottom of the bed in the reactor.
This gasifier is characterized by high gas exit temperature, very high solid particulate
matter in the gas and relatively low efficiency. The gasifier can operate with low bulk
density materials such as agro-residues, leaves, etc.
FLUIDIZED BED GASIFIER

62. ENVIRONMENTAL BENEFITS
• The use of biomass energy has many unique
qualities that provide environmental benefits
• It can help mitigate climate change, reduce acid
rain, soil erosion, water pollution and pressure on
landfills, provide wildlife habitat and help
maintain forest health through better management

63. ENVIRONMENTAL BENEFITS