Training on
Technologies for Converting Waste Agricultural Biomass into Energy
Organized by
United Nations Environment Programme (UNEP DTIE IETC)
23-25 September, 2013
San Jose, Costa Rica
Characterization of Waste
Agricultural Biomass for
Energy Applications
Surya Prakash Chandak
Senior Programme Officer
International environmental Technology Centre
Division of Technology, Industry and Economics
Osaka, Japan
UNEP
Why Characterisation of WAB
Characterization of WAB provides
essential information for:
• Selection of WAB2E technology
• System design
• Assessment of operational
performance
• Provides data for tendering
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International Environmental Technology Centre
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Characterization of waste agricultural
biomass
Parameters of characterization
• Visual characterization
• Moisture content
• Chemical Composition
• Calorific value
• Specific characterization parameters
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International Environmental Technology Centre
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Characterization of waste agricultural
biomass
Visual characterization
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Source
Waste Stream
Visual Observations
Commercial Facilities
Fruit and vegetable
waste
High moisture
(estimated to be 6080%), sometimes
putrified, mixed with
packing hay
Corporate Farms
Rice husk
Clean, stacked in
heaps, approximate
volume …m3
Jaggery Plants
Bagasse
Moist waste (estimated
moisture 50%),
scattered around, some
spread on ground for
sun-drying, mixed with
barbojo
Private farms
--
--
--
--
--
International Environmental Technology Centre
UNEP
Characterization of waste agricultural
biomass
Moisture content
Two ways of reporting
Moisture content on wet basis (MCwb)
Moisture content on dry basis (MCdb)
MCdb 
MCwb
.
1  MCwb
Relationship between MCwb and MCdb
Moisture Content on Dry Basis
2.5
2.0
1.5
1.0
0.5
0.0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Moisture Content on Wet Basis
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International Environmental Technology Centre
UNEP
Characterization of waste agricultural
biomass
Chemical composition – Ultimate Analysis
Percent by weight (dry basis)
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Component
Carbon
Hydrogen
Oxygen
Nitrogen
Sulphur
Ash
Wheat Straw
48.5
5.5
39.9
0.3
0.1
5.7
Rice Straw
39.2
5.1
35.8
0.6
0.1
19.2
Rice Husk
38.5
5.7
39.8
0.5
<0.01
15.5
Bagasse
46.4
5.4
42.6
0.7
<0.01
4.9
Hard Wood
50.8
6.4
41.5
0.4
<0.01
0.9
Soft Wood
52.9
6.3
39.7
0.1
<0.01
1.0
Corn Cob
46.2
7.67
42.3
1.2
0.3
2.4
Cotton stalk
45.3
5.6
45.3
0.5
<0.01
3.3
Anthracite coal
78.8
2.3
2.5
0.9
0.5
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International Environmental Technology Centre
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Characterization of waste agricultural
biomass
Chemical composition – Proximate Analysis
Percent by weight (dry basis)
Volatile Matter
(%dry ash free basis)
Component
7
Fixed Carbon
(%dry ash free basis)
Ash
(% dry basis)
Wheat Straw
83.9
16.1
11.2
Rice Straw
80.2
19.8
19.8
Rice Husk
81.6
18.4
23.5
Bagasse
84.2
15.8
2.9
Wood
77-87
13-21
0.1-2.0
Peanut shell
78.4
21.6
7.2
Corn Cob
85.4
14.6
2.8
Cotton stalk
80.0
20.0
5.3
Anthracite coal
5.9
94.1
15.0
International Environmental Technology Centre
UNEP
Characterization of waste agricultural
biomass
Energy Content
Three expressions:
Higher Heating Value (HHV) or Gross Calorific Value (GCV)
Lower Heating Value (LHV) or Net Calorific Value (NCV)
Usable Heat Content
HHV – Total energy generated from combustion including the heat of
condensation of water vapor – represents maximum theoretical
potential energy
LHV -- Total energy generated from combustion less the heat of
condensation of water vapor – represents maximum realizable
energy
UHC – LHV less the sensible heat of the combustion products –
represents actual usable energy
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Characterization of waste agricultural biomass
UNEP
Relationships between heating values
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UNEP
– HHV of wet biomass = (1-m)HHVD
– LHV = (1-m)HHVD - (latent heat)(moisture content
in product gas per kg fuel)
= (1-m)HHVD – 2.447[m + 9.0(1-m)H]
– Utilizable heat content =
LHV - [(mass fraction)
(CP)]all products(Texht - Tamb)
where m is the fractional moisture content in biomass
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UNEP
Characterization of waste agricultural biomass
UNEP
Estimation of Higher Heating Value of WAB
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– Usually, heating values of biomass materials are determined
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through direct experimental measurement by means of a
device called bomb calorimeter
– Alternative to the practical measurements, approximate
estimations for HHVD could be made through analytical
equations that are derived based on fuel composition
–
Based on ultimate analysis
Three models:
–
–
Model – X: HHV=0.352xC + 1.162xH – 0.111xO + 0.063xN + 0.105xS
–
Model – Y: HHV=0.349xC + 1.178xH – 0.103xO + 0.015xN + 0.101xS – 0.021A
–
Model – Z: HHV=0.341xC + 1.323xH – 0.120xO + 0.120xN + 0.680xS – 0.015A
–
HHV – Higher Heating Value in MJ/Kg
–
C,H,O,N,S,A are the % mass fractions of Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur and Ash
respectively in dry biomass.
Try matching with the formula !!
•
Q = 337C + 1442(H - O/8) + 93S
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Characterization of waste agricultural biomass

Estimation of Higher Heating Value of WAB
Based on ultimate analysis
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Biomass
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FuelUNEP
Composition (% by weight)
C
Paddy Straw
Paddy Husk
Corn Cob
Bagasse
Cotton Stalk
Hard Wood
Soft Wood
Miscanthus
Barley
Straw
39.2
38.5
46.2
46.4
45.3
50.8
52.9
48.1
45.7
Wheat Straw 48.5
Lignite
64.0
Anthracite
78.8
H
O
N
S
HHVD (MJ/kg)
Ash Model
X
Model
Y
Model
Z
15.8
15.8
20.5
17.9
17.4
20.7
21.5
18.5
18.9
15.6
15.7
20.7
18.1
17.7
21.0
21.8
18.7
19.0
15.5
15.6
20.6
17.7
17.3
20.7
21.6
18.4
18.9
5.5
39.9
0.3 0.1 5.7 19.0
4.2
19.2
0.9 1.3 10.4 25.4
2.3
2.5
0.9 Technology
0.5 15
International
Environmental
Centre 30.2
19.2
25.2
29.7
18.9
24.9
29.3
5.1
5.7
7.6
5.4
5.6
6.4
6.3
5.4
6.1
35.8
39.8
42.3
42.6
45.3
41.5
39.7
42.2
38.3
0.6
0.5
1.2
0.7
0.5
0.4
0.1
0.5
0.4
0.1
0
0.3
0
0
0
0
0.1
0.1
19.2
15.5
2.4
4.9
3.3
0.9
1.0
3.7
9.4
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Characterization of waste agricultural biomass
UNEP
Estimation of Higher Heating Value of WAB
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 Based on ultimate analysis
Biomass constituent /
Chemical equation
Cellulose / (C6H10O5)x
Hemicelluloses / (C5H8O4)y
Lignin /
(C9H10O3(CH3O)0.9 – 1.7)z
Ultimate Analysis (%)
HHVD (MJ/kg)
Model Model Model-X
-Y
Z
17.3
17.7
17.4
C
H
O
44.4
6.2
49.4
45.5
6.1
48.5
17.6
18.0
17.7
58.7 –
61.3
6.5 – 32.2 – 24.9
6.9
34.4
–
25.6
25.1
25.0
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–
–
25.8
25.7
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Characterization of waste agricultural biomass
Estimation
of Higher Heating Value of WAB
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 Based on proximate analysis
Three Models
 Model A: HHV = 0.1559xVM + 0.3536xFC – 0.0078xA
 Model B: HHV = 0.1708xVM + 0.3543xFC
 Model C: HHV = 0.3133x(VM+FC) – 10.8141
HHV – Higher Heating Value in MJ/Kg
VM, FC,A are the % mass fractions of Volatile Matter, Fixed Carbon and
Ash respectively in dry biomass.
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UNEP
Characterization of waste agricultural biomass

Estimation of Higher Heating Value of WAB
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UNEP Based on proximate analysis
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Biomass Fuel
Bagasse
Coconut coir
Coconut shell
Coir pith
Corn cob
Corn stalks
Groundnut shell
Paddy Husk
Paddy Straw
Wheat Straw
Peanut Shell
Cotton Stalk
Composition (% by weight)
Ash
VM
FC
(ash free) (ash free)
84.2
82.8
80.2
73.3
85.4
80.1
83.0
81.6
80.2
83.9
78.4
80.0
15.8
17.2
19.8
26.7
14.6
19.9
17
18.4
19.8
16.1
21.6
20.0
2.9
0.9
0.7
7.1
2.8
6.8
5.9
23.5
19.8
11.2
7.2
5.3
HHVD (MJ/kg)
Model- Model- ModelA
B
C
18.1
19.4
19.6
18.8
20.1
20.2
19.4
20.6
20.3
19.3
20.4
18.3
17.9
19.2
19.6
18.1
19.3
18.4
17.8
19.0
18.7
14.5
15.6
13.2
15.5
16.6
14.3
16.6
17.8
17.0
18.4
19.5
18.3
18.5
19.7
18.9
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Characterization of waste agricultural biomass
 Effects of Moisture on Heating Value
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LHV


20.0
HHV of wet biomass 
1 - m HHVD .
1 - m HHVD - (latentheat) (moisturecontentin product gas per kg fuel)
1 - m HHVD - 2.447 m  9.0  1  m H , ,
Wood Pellet
(8% moisture)
18.0
Heating Value (MJ/kg)
16.0
14.0
Green Wood
(50% moisture)
12.0
Air Dried Wood
(20% moisture)
10.0
LHV
8.0
HHV
6.0
4.0
2.0
0.0
0
0.1
0.2
0.3
0.4
0.5
Moisture
Content onTechnology
Wet Basis Centre
International
Environmental
0.6
0.7
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HAPPY WORKING ON
CHARACTERIZATION OF
WASTE AGRICULTURAL
BIOMASS
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THANK YOU
For further information:
http://www.unep.or.jp
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