A Simple Alternative to Charcoal

y Chris Lanning (Forest Concepts)
& Paul Means (Burn Design Lab)

A Simple Alternative….
Background
Issues with Charcoal
Charcoal and Alternative Value Chains
Size Reduction
Drying
Transport Considerations
Fuel Utilization
Next Steps
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A Simple Alternative - Background
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Charcoal Use
Sub-Saharan Africa
○ 11% of population use
charcoal as primary fuel.
○ 69% use woody
biomass.
Kenya, 30% of urban
dwellers use charcoal as
primary fuel
Uganda, 60% of urban
population use charcoal
3

A Simple Alternative - Background
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Advantages to Charcoal
Employment
○ The estimated charcoal producers in
Kenya is 200,000.
○ Approximately 500,000 people engage
in downstream-processing and trade.
○ the economic value of the charcoal
industry in SSA may exceed US$12
billion by 2030, employing almost 12
million people.
Clean burning – low
particulate emissions
Very convenient
Fuel Conservation – user can
save unused fuel.
Low capital production
4

Issues with Charcoal
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Environmental Impact –
charcoal made from live
trees (Deforestation rate
in Sub-Saharan Africa
~0.8%)
In Kenya 2006, biomass
demand was estimated at
38.1 million tonnes
against a sustainable
supply of 15.4 million
tonnes, creating a
demand-supply deficit of
60 percent.
High CO emissions from
burning charcoal
Low production efficiency
5

System Efficiency – Traditional
Charcoal Production & Use
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Charcoal
Production
Efficiency = 15%
Efficiency = energy
output / energy input
Charcoal Stove
Efficiency = 25% Net System
Efficiency = 4%
Wood Energy Charcoal Energy Cooking Energy
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System Efficiency – Improved
Charcoal Production & Use
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Charcoal
Production
Efficiency = 25%
Efficiency = energy
output / energy input
Charcoal Stove
Efficiency = 45%
Net System
Efficiency = 11.5%
Wood Energy Charcoal Energy Cooking Energy
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Value Chains
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Charcoal
Wood
Production
• High
Consumption
Charcoal
Production
• Low
Efficiency
• Low Capital
Transport
• High Energy
Density
Wholesale /
Retail
• Well
Established
Use
• Variable
Efficiency
• Low
Particulate
• High CO
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Value Chains
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Alternative – sized & dried biomass
Wood
Production
• Low
Consumption
Size
Reduction &
Drying
• High
Efficiency
• Moderate
Capital
Transport
• Moderate
Energy
Density
Wholesale /
Retail
• Not
Established
Consumption
• High
Efficiency
• Low
Emissions
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System Efficiency –Sized & Dry Biomass
Production & Use
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Sizing & Drying
Efficiency = 75+%
Micro-Gasifier Stove
Efficiency = 40+%
Net System
Efficiency = 30+%
Wood Energy S & D Wood Energy Cooking Energy
3 Fold increase over improved charcoal system efficiency
8 fold increase over traditional charcoal system efficiency
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Size Reduction (Comminution)
Saw
Grinder
Shredder
Chipper
Knife Mill
Lathe
Crumbler
…
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Size Reduction (Comminution)
Grinder
Mech. Energy (kW-hr/t*)
○ 85-420
Benefit
○ Can be HUGE 100 t/hr
○ Many configurations
○ Very tolerant of feedstock impurities
Limitation
○ Material handling challenges
Stringy, “broom ends”, non-flowable
○ Sensitive to moisture content
Energy increases with mc
○ Minimum piece size
Energy increases very quickly as size decreases
○ Wide piece size distribution
* t= 1000 oven dry kg mass
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Size Reduction (Comminution)
Chipper / Knife Mill
Mech. Energy (kW-hr/t)
○ 25-140
Benefit
○ More Efficient
○ Many configurations
Limitation
○ Material handling
Minimal flowability
○ Grit intolerance
Grit dulls knives quickly
○ Minimum piece size
Limitation to minimum piece size
○ Moderate piece size distribution
Material pic
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Size Reduction (Comminution)
Auger Chipper
Mech. Energy (kW-hr/t)
○ 25-140
Benefit
○ Efficient
○ Moisture tolerance
Limitation
Effective over wide moisture range
○ Material handling
Minimal flowability
○ Grit intolerance
○ Product size range
Larger particles
○ Wide piece size distribution
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Size Reduction (Comminution)
Lathe
Mech. Energy (kW-hr/t)
○ 2-6
Benefit
○ Very Efficient
○ Uniform product
○ Transportable
Limitation
○ Veneer?
Easily rolls or stacks
Intermediate product
○ Grit tolerance
Grit wears blade
○ Out of round material
Lost yield, can be difficult to start
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Size Reduction (Comminution)
Crumbler®
Mech. Energy (kW-hr/t)
○ 15-55
Benefit
○ Very efficient
○ Narrow piece size distribution
○ Material handling
Highly flowable
○ Moisture tolerance
Limitation
More efficient with high mc
○ Grit intolerance
○ Size range
16 mm maximum in 1 dimension
○ Second stage size reduction
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Size Reduction (Comminution)
Particle shape consideration, Flowability
Pellets
Ground pellet furnish
(in front of glass)
Pouring
Glass
Crumbles®
4mm Particles
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Size Reduction (Comminution)
Summary
kW-hr/t
300
250
200
150
100
50
0
Mechanical Energy
Grinder Chipper Screw
Chipper
Particle Size and Shape Matter
Lathe Crumbler®
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Drying
Types
Rotary drum
Fluidized bed
Belt
Deep bed (grain)
Tarp
Fuels
Fossil fuel
Electric (very limited)
Wood
Other biomass
Sun
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Drying
Types
Rotary drum
Fluidized bed
Belt
Deep bed (grain)
Tarp
Fuels
Fossil fuel
Electric (very limited)
Wood
Other biomass
Sun
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Transport Considerations
Energy Density
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Relative Energy Density
(lower heating value / kg)
Charcoal @
3% Moisture
Hardwood @
10% Moisture
Hardwood @
40% Moisture
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Transport Considerations
Hauling Cost
Impact due to
lower net heating
value for raw
biomass.
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Charcoal @ 3%
Moisture
Haul Cost Multiplier
Hardwood @
10% Moisture
Hardwood @
40% Moisture
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Transport Considerations
RElative Haul Distance
160%
140%
120%
100%
80%
60%
40%
20%
0%
Forest Area Required and Relative Haul Distance
Forest Required
to Support
Traditional
Charcoal
Forest to
support
Improved
Charcoal
Forest for
Alternative
0 1 2 3 4
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Transportation Considerations – cont.
Net Hauling Cost =
Energy Density * Haul
Distance
100%
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90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Relative Net Hauling Cost
Traditional
Charcoal
Improved
Charcoal
Alternative

Fuel Utilization
Micro-Gasifiers get
their day in the sun..
Efficiency = 40+%
Low CO and PM2.5
emissions
Well suited for
standardized dry
chunky fuel.
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Conclusions
The charcoal value chain is very
inefficient.
Size reduction & drying of woody
biomass, combined with microgasification
can displace charcoal as a
fuel for urban dwellers.
The new value chain, if developed,
would
reduce forest usage by 66 to 87%
Reduce indoor air pollution.
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Next Steps
Comparative Economic Analysis of Value
Chains
Development of right sized equipment for size
reduction.
Evaluation of alternative drying technologies
Optimization of the fuel for:
Low capital cost
Low purchased energy costs
Storage, handling, & combustion characteristics
Stove design
Pilot the Alternative (Kenya Stove)
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Thank You!
Questions??
Chris Lanning
clanning@forestconcepts.com
Paul Means
paul@burndesignlab.org
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