22. BIOMASS GASIFICATION.ppt

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
CombustionGasificationPyrolysis
DigestionFermentation
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 residuesAgro-Industrial residuesForest 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 -POTENTIAL AND 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
Highmoisturecontent:reducetemperaturepoor
qualitygas
Bestgas:moisturecontent15%
Lowermoisturelevel:Hydrogendecreases
Highermoisturelevel:COdecreases
Highermoisture:probleminsmoothoperation

13. TEMPERATURE
Highertemperatureaccountforhighercarbon
monoxideandlowermethane
Thehydrogencontentincreasesuptoatemperatureof
1100°Fandstartsdecreasing
Highertemperaturearound1500°Fisconsideredmore
suitableforgasification

14. PRESSURE
Thegasifierpressurehasnoteffectonthegasquality,
orthegasificationefficiency
However,thehigherpressureisknowntoincreasethe
gasificationrateandthegasifiercapacity

15. FUEL SIZE AND SHAPE
Sizeandshapeofthefuelplaysanimportantrolefor
smoothoperation
Toosmall:increasethepressuredropwhichleadsto
materialflowproblems
Thebiggerfuelsize:flowprobleminthethroatun-
pyrolysedbiomass
Appropriatefuelsize:selectedwithrespectthe
reactortype

16. •Biomassgasificationisathermo-chemicalprocessby
which,biomasscontainingcarbon,hydrogenand
oxygenisreactedwithrestrictedamountofair/
oxygenand/orsteamtoyieldamixtureofcombustible
gasesconsistingofcarbonmonoxide,hydrogenand
tracesofmethane.Thismixtureiscalledproducergas
•Gasificationaccomplishedinairsealedchamber-
slightsuctionorpressurerelativetoambientpressure
Heat + biomass = gas + pyrolytic oils + char +ash +
steam
BIOMASS GASIFICATION

17. GASIFICATION
•Gasificationisapartialoxidationprocesswherebya
carbonsourcesuchascoal,naturalgasorbiomass,is
brokendownintocarbonmonoxide(CO)andHydrogen
(H
2)pluscarbondioxide(CO
2)andpossiblyhydrocarbon
moleculessuchasmethane(CH
4)
•Thismixofgasisknownasproducergasandtheprecise
characteristicsofthegaswilldependonthegasification
parameterssuchastemperatureandalsotheoxidizerused
•Theoxidizermaybeair,inwhichcasetheproducergas
willalsocontainNitrogen(N
2),orsteamoroxygen

18. GASIFIER
•Gasifierisanequipmentwhichcangasifyavarietyof
biomasssuchaswoodwaste,agriculturalwasteslike
stalksandrootsofvariouscrops,maizecobs,etc.
•Thegasifierisessentiallyachemicalprocessestake
place.Biomassgetsdried,heated,pyrolyzed,partially
oxidizedandreduced,asitflowsthroughit.
•Thegasproducedinthegasifierisacleanburning
fuelhavingcalorificvalueofabout950to1200
Kcal/m
3
.
•Hydrogen(18-20%)andcarbon-monoxide(18-
24%)arethemainconstituentsofthegas.
•Theadvantagesofagasifierareveryeasytooperate,
maintain,sturdyinconstructionandreliablein
operation

19. 1.Grate
2.Throat
3.Airnozzle/airdistributionsystem
4.Ashremovalsystem/ashremovalport
5.Gasoutlet
6.Ignitionport
7.Biomassfeedingport
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 H
1.4O
0.6 + 1.05(O
2+ 3.76 N
2) CO
2+ 0.7 H
2O + 3.95 N
2
Mass : 23 144.1 44 12.6 110.5
GASIFICATION
C H
1.4O
0.6+ 0.35 O
2 0.4 CO + 0.6 H
2+ 0.4 CO
2 + 0.1 H
2O + 0.2 C
EQUIVALENCE RATIO

21. Theequivalenceratioincreasesthecarbonmonoxide
levelofproducergasincreases(afterpassingthrougha
maximumatequivalenceratioof25%startsdecreasing
andthecarbondioxidestartsincreasing)
Themethanecontentofproducergasdecreaseswith
increasingΦupto0.25

22. Gasifier: Areactorwhichconvertssolidfuelsintogaseous
fuelthroughthermo-chemicalprocessunder
controlledconditionofair
Producergas:Itisamixtureofgasesproducedwhenmaterials
likewood,charcoal,coal,ligniteorcropresidue
areburntundercontrolledconditionofair
Pyrolysis:Itistheprocesswhereinheatisusedto
breakdownbiomassintheabsenceofairtoyield
charcoal,wood-oils,tarsandgases
Pyrolysiszone:Inthiszone,thesolidmaterialstarts
disintegratingat250°Ctoproducecharaswellas
condensableandnon-condensablegases
TERMINOLOGIES PERTAINING TO
GASIFICATION

23. Oxidationzone:Inthiszone,airisintroducedforoxidationof
biomass.Apartfromheatgeneration,all
condensable&organicproductsofpyrolysisget
convertedandoxidized
Reductionzone:Inthiszone,sensibleheatofgasesandcharcoal
isabsorbedinendothermicreactionsbetween
water,CO
2
andcarboninthecharcoal
Turndownratio:Turndownratioofagasifieristheratioof
maximumtominimumgasgenerationratesat
whichitcanbereasonablyandefficientlyoperated
withoutdropinqualityofgas
Specificgasificationrate:Specificgasificationrateisthequantity
ofbiomassconsumedperunittimeandunitcross-
sectionalareaofgasifier

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 -1450
0
C
C + O
2= CO
2(+ 393 MJ/kg mole)
2H
2+ O
2= 2H
2O (-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
H
2O (Moisture H
2O
(Steam)
C
xH
yO
zVolatile gas and
liquid
C + O
2= CO
2+ 406 KJ/g.
mols
Primary reduction zone 825°C
Secondary reduction zone
Solid residue and gas 540°C
C +H
2O = CO + H
2+ 131.4 kJ / g. mole
C+2H
2O= CO
2+2H
2+78.75 kJ /g. mole
C + CO
2= 2CO –172.6 kJ/g. mole
C + CO
2= 2CO –172.6 kJ/g. mole
CO
2+ H
2= CO + H
2O –412 kJ/g. mole
2 CO = CO
2+ C

27. 4O
2
- - - - 16.15-
5CH
4
08.1704.9404.7504.7512.4000.75
6C
2
H
6
00.4300.2600.2500.2512.30-
Sl.NoGasesWood Corn
cob
Barley
straw
Tree
pruning
Rice
straw
Peat
1CO
2
09.7010.9013.7013.7008.4015.30
2CO 23.9020.9018.8018.8015.3016.15
3H
2
16.3013.4016.4016.4026.1012.30
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]
CO
2 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)Fuelconsumption(q)q=
Where:
q= fuelconsumption,kg/h
P=engineoutput,kW
=overallefficiency,i.e.(GasificationefficiencyXEngine
combustionefficiency)
H
w
=lowerheatingvalueofbiomass,kJ/kg
(II)Quantityofgasproduced,Q=
Where:
=gasificationefficiency
q =fuelconsumption,kg/h
H
w
&H
g
=lowercalorificvaluesofbiomassandproducergasin
kJ/kgandkJ/Nm
3
(III)Volumeofreactor,V=
Where:
t= timeofoperation
S
p
=pileddensityofbiomass,kg/m
3wtotH
P



3600 o g
wc
H
Hq c p
S
qt
DETERMINATION OF VARIOUS PARAMETERS OF
THROATLESS GASIFIER

36. Rateoffuelconsumption,kg/h
(IV)Arearequired,A=-----------------------------------------
Specificgasificationrate,kg/hm
2
Diameterofthereactor,D=
(V)Heightofthereactor,h =4/
A 2
4
D
V


DETERMINATION OF VARIOUS PARAMETERS OF
THROATLESS GASIFIER

37. Parameters,whichinfluencesthegratedesign,are:
(i)Rateofashremoval
(ii)Superficialgasvelocityandflowfield
(iii)Sizedistributionofthechar
(iv)Bulkdensityofthechar
(v)Constructionandcostmaintenance
Theareaofgratemaybecalculatedbyfollowingformula:
Where,
A=gratearea,m
2
q=biomassconsumption,kg/h
SGR=specificgasificationrateofbiomass,kg/h-m
2
Thediameterofgrate:A
q
SGR
 D
A

4
 Type of throat Average capacity (SGR),
kg/h-m
2

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 kW
thT 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 ArasiHi-Tech BiopowerLtd., 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. Thisgasifiercanoperatewithwide
varietyoffuelscomparedtoanup
draftoradowndraftgasifier
Highgasexittemperature,higher
gasvelocityatthegasexit
PoorCO
2reductionarecertain
characteristicsofthistypeofgasifier
Thistypeofgasifierhasbeenused
forgasificationofcoal
Reaction zones in a cross draft gasifier
CROSS DRAFT GASIFIER

59. FLUIDIZED BED GASIFICATION
Definition
Afluidizationbedisachamberwithaperforatedfloor
havingpressurizedairflowingverticallywhereaparticle
mediumusuallysand,iscontained.Thepressurizedand
flowingairhelpsthemediumallowingittoactasafluid

60. PRINCIPLE OF FLUIDIZED BED
GASIFICATION
•Canusemostfuels(wood,
peatandcoal)including
agriculturewastesuchas
straw,cornstoverand
manure
•Haspotentialtouse
municipalwastesuchas
garbage
•Quickerinresponse
•Hasshorterstarttime
•Complexdesign
•Lendsitselftocomplete
combustion applications
whichwouldallowittouse
liquidwastessuchasused
engineoil,non-recyclable
plastics&oldshoes,garbage
forgenerationofheat

61. Fluidizedbedgasifierisahomogeneousreactorbedofsomeinertsandmaterial.The
fuelisintroducedintheinertbedmaterialandairatthebottomofthebedinthereactor.
Thisgasifierischaracterizedbyhighgasexittemperature,veryhighsolidparticulate
matterinthegasandrelativelylowefficiency.Thegasifiercanoperatewithlowbulk
densitymaterialssuchasagro-residues,leaves,etc.
FLUIDIZED BED GASIFIER

62. ENVIRONMENTAL BENEFITS
•Theuseofbiomassenergyhasmanyunique
qualitiesthatprovideenvironmentalbenefits
•Itcanhelpmitigateclimatechange,reduceacid
rain,soilerosion,waterpollutionandpressureon
landfills,providewildlifehabitatandhelp
maintainforesthealththroughbettermanagement

63. ENVIRONMENTAL BENEFITS