Enhancing Sustainability In Tobacco
Production : Energy Efficient Curing
Barn Development For Smallholder
Growers In Zimbabwe
CORESTA CONGRESS 2016, BERLIN.
Wisdom Munanga TOBACCO RESEARCH BOARD
KUTSAGA
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PRESENTATION OUTLINE
• Barns and Curing fuel – Zimbabwean Situation
• The shift in the grower base – associated challenges
• The Alternatives (Alternative fuels, Adoption of
new barn designs)
• Energy efficient barn (the design, efficiency tests)
• Discussion and conclusion
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• Zimbabwe has for decades
been known as the source of
some of the world's finest
flavour tobacco.
• Pre-2000, 80% of the crop
grown by large scale
commercial growers.
BACKGROUND
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• The crop
predominantly
cured using coal as a fuel source.
• Growers had a
wide range of barn options.
BACKGROUND
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THE BARN TYPES : CONVENTIONAL
• ~2 – 3 ha
capacity
• 2 – 2.5 kg of
coal per kg of
cured
tobacco
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THE BARN TYPES : CASCADE
• ~14 ha
capacity
• 1.5 – 2 kg
of coal per
kg of
cured
tobacco
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BARNS : BULK CURERS
• ~3 ha capacity
• ~ 2 kg of coal
per kg of cured
tobacco
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THE BARN TYPES : TUNNEL BARN
upto 120 ha capacity
0.9 – 1kg of coal per
kg of cured tobacco
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THE BARN TYPES : TUNNEL BARN
upto 120 ha capacity
0.9 – 1kg of coal per
kg of cured tobacco
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But change is inevitable…. • In 2003 – grower base
changes
• 85% of crop grown by
small scale growers.
• On 1-2 ha per individual
• Mostly dependent on wood for curing (coal
expensive, not on electricity grid)
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CONSEQUENCIES - LOSS OF INDEGINOUS TREES
• Indigenous trees used
as fuel sources
• However, barns
designed for coal
• Inefficient, with SFC of
as high as14 kg.
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EXTENT OF DEFORESTATION IN ZIMBABWE
The indigenous msasa tree or
zebrawood
(Brachystegia_spiciformis)
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EXTEND OF DEFORESTATION IN ZIMBABWE
The indigenous msasa tree or
zebrawood
(Brachystegia_spiciformis)
2008 Pfura district, Mt
Darwin, Zimbabwe
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EXTEND OF DEFORESTATION IN ZIMBABWE
The indigenous msasa tree or
zebrawood
(Brachystegia_spiciformis)
2008 Pfura district, Mt
Darwin, Zimbabwe
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DEFORESTATION IN ZIMBABWE....
1. Expansion of agricultural land,
2. Land clearing for resettlement
3. Tobacco curing (15%)
4. Energy provisions (household energy
consumption based on woodfuel)
5. Veld fires
6. Other (curing of bricks, construction poles)
Zim- Forestry Commission
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DEFORESTATION IN ZIMBABWE....
1. Expansion of agricultural land,
2. Land clearing for resettlement
3. Tobacco curing (15%)
4. Energy provisions (household energy
consumption based on woodfuel)
5. Veld fires
6. Other (curing of bricks, construction poles)
Zim- Forestry Commission
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DEFORESTATION IN ZIMBABWE....
1. Expansion of agricultural land,
2. Land clearing for resettlement
3. Tobacco curing (15%)
4. Energy provisions (household energy
consumption based on woodfuel)
5. Veld fires
6. Other (curing of bricks, construction poles)
Zim- Forestry Commission
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DEFORESTATION IN ZIMBABWE....
1. Expansion of agricultural land,
2. Land clearing for resettlement
3. Tobacco curing (15%)
4. Energy provisions (household energy
consumption based on woodfuel)
5. Veld fires
6. Other (curing of bricks, construction poles)
Zim- Forestry Commission
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DEFORESTATION IN ZIMBABWE....
1. Expansion of agricultural land,
2. Land clearing for resettlement
3. Tobacco curing (15%)
4. Energy provisions (household energy
consumption based on woodfuel)
5. Veld fires
6. Other (curing of bricks, construction poles)
• 300,000 ha of woodlands
lost annually - Forestry
Commission
• 15% of deforestation rate
- tobacco curing.
Zim- Forestry Commission
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So, What is the tobacco
industry doing about their
contribution?
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ZIMBABWEAN TOBACCO INDUSTRY INTERVENTIONS
Three pronged approach
1. Promoting woodlot
establishment by growers
2. Search for alternative
fuels
3. Energy efficient curing
systems
TRB INITIATIVES TOBACCO MERCHANTS
• Sustainable
Afforestation
Association (SAA)
– Formed (2013)
• Initiates
reafforestation
programmes
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1. Promote woodlot establishment
TRB INIATIVES IN DETAIL 2016
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TRB’S GOSIP – 3Ps
2010 - TRB initiates the
”Governance and Social
Investment Programme
for People, Planet and
Profit” - GOSIP-3Ps
programme
Eucalypt seedbed at
Kutsaga - 2016
TRB’S GOSIP-3PS
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TRB’S GOSIP – 3Ps
2010 - TRB initiates the
”Governance and Social
Investment Programme
for People, Planet and
Profit” - GOSIP-3Ps
programme
Eucalypt seedbed at
Kutsaga - 2016 Objective : Ensure responsible, sustainable &
viable tobacco production through
encouraging growers to;
• Nurture and manage indigenous forests
• Establish own woodlots
TRB’S GOSIP-3PS
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THE ACTIONS
• Provision of free
eucalyptus seed &/or
seedlings to growers
• Train growers on
eucalypt tree
production.
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• Seed worth 500 000 ha distributed & ~58 %
established (329/559)
• Seedlings - 3.5 million ha
equiv. Collected & ~40 % were planted
TRB PROGRESS TO DATE
Government introduces the Tobacco wood energy act in 2012
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INDUSTRY EFFORT - SAA
Sustainable Afforestation Association, a non
profit organization formed by the Tobacco
merchants in 2013.
Objectives : to provide a sustainable source of
timber for the tobacco industry &
to implement strategies to conserve & rejuvenate
indigenous & commercial forests
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SAA ACHIEVEMENTS TO DATE
• 8 000 ha of
eucalypt
plantations established
• Annually ~12 million trees (@
1600 plants/ha)
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SOME CHALLENGES…..
1. Veld fires
2. Pests and disease e.g.
blue gum wasp and the
red gum lerp psyllid
TRB /Forestry
Commission/ SAA -
working on biocontrol
options
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OTHER TREE ALTERNATIVES
• Bamboo
• Arcacia
• Msasa
Msasa tree seedlings @
Kutsaga
Bamboo trial @
TRB
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2. Alternative fuels
TRB INIATIVES IN DETAIL cntd 2016
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SOLAR
• 100 % solar curing
system was evaluated.
• Temperatures not more than 57 °C.
• Great potential as
hybrid system.
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COAL BRIQUETTES
• Made from coal dust.
• Can burn unassisted with
forced air.
• Curing tests indicated a
SFC of 4 kg @ CE of 75%.
• This was recommended.
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BIOGAS
• Can be produced on the
farm.
• Curing tests were
conducted.
• Recommended in a
hybrid system.
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ETHANOL
• Production at ~ 300 000
L/day
• Curing tests indicate SFC of
2-3 L.
• Pursuing cost reduction &
heat exchanger efficiency.
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3. Energy efficient barns
TRB INIATIVES IN DETAIL cntd
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THE ROCKET BARN
• 2011 - extensive research to
modify rocket for Zim conditions.
• Modified barn - fuel efficient (SFC
of 4 kg).
• Adopted and widely used by most
small scale growers.
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THE ROCKET BARN
• 2011 - extensive research to
modify rocket for Zim conditions.
• Modified barn - fuel efficient (SFC
of 4 kg).
• Adopted and widely used by most
small scale growers.
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ROCKET BARN : LIMITATIONS
• Low capacity (max. 15 000
leaves)
• High cost of some
components e.g. the
double chimney
Hence the need for bigger
capacity but low cost barn
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KUTSAGA COUNTER CURRENT
1 (KCC1) BARN DEVELOPED
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Roof IBR sheet Light weight and affordable
Design feature Description Comments
Furnace V-slot and in protruding inside the
barn Efficient fuel-air mixing
Heat exchanger Brick firebox channel with metal
top surface
Stable temperature
Walls Farm brick, double wall Low cost
Exhaust chimney Brick channel, built inside the barn Exhaust heat retention
Ceiling Thatch grass insulation
Capacity 1200 clips (45 000 leaves) Economically suitable for
small scale growers
KUTSAGA COUNTER CURRENT 1 SPECIFICATIONS
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• Uses a counter-current
airflow principle IE
• the 2 fluids involved in
heat exchange flow in
opposite directions.
• More efficient heat exchange system.
KCC1 – THE PRINCIPLE
KCC1 barn @ Kutsaga
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• Uses a counter-current
airflow principle IE
• the 2 fluids involved in
heat exchange flow in
opposite directions.
• More efficient heat exchange system.
KCC1 – THE PRINCIPLE
KCC1 barn @ Kutsaga
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BARN DESCRIPTION
Rocket 1 (R1) Brick firebox with double metal chimney
Rocket 4 (R4) Brick firebox with double metal chimney
Conventional 1 (control) Flue pipe system and brick chimney outside the barn
KCC1 barn (test) Brick double firebox with brick chimney inside barn
KCC1 EFFICIENCY EVALUATION TEST
The treatments
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1. Quantity of leaf loaded into barn
2. Duration of each curing stage recorded
3. Cured leaf quality (TRB’s Grade Index)
4. Specific Fuel Consumption (SFC) - (wood
mass : leaf mass)
MEASUREMENTS
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DATA ANALYSIS
• The trial was repeated six times
• Data tested for normality of residuals and
homogeneity of error variance
• Subjected to analysis of variance (ANOVA)
using GENSTAT statistical analysis package,
17th edition.
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RESULTS AND DISCUSSION
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BARN CAPACITY
Rocket 1 (R1) 0.5 ha
Rocket 4 (R4) 0.6 ha
Conventional 1 0.8 ha
KCC1 barn 1.5 ha
QUANTITY OF LEAF LOADED INTO BARN
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1. TIME TAKEN TO COMPLETE CURING
• In the end, all barns took
similar time taken to
complete the curing cycle
(7 days).
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1. TIME TAKEN TO COMPLETE CURING
• In the end, all barns took
similar time taken to
complete the curing cycle
(7 days).
BARN FUEL CONVERSION EFFICIENCY
7.22
11.6 10.5
23.99
0
5
10
15
20
25
30
Conv 1(Standard) Rocket (R1) Rocket (R4) KCC1 (Test barn)
Fu
el C
on
ve
rsio
n E
ffic
ien
cy
(%
)
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2. LEAF QUALITY - GRADE INDEX (%)
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3. SPECIFIC FUEL CONSUMPTION (SFC)
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SUMMARY & CONCLUSION
1. KCC1 Barn had a higher capacity – 1.5 ha
2. Recorded the lowest SFC
3. Leaf quality and turn around time
maintained
4. Use of energy efficient barns (Rocket &
KCC1) and own curing fuel or alternative
fuels – can curb deforestation
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OVERAL SUMMARY
Zimbabwe ensuring sustainability in tobacco
production through;
• Re - afforestation programmes (TRB/SAA)
• Research on alternative curing fuel sources
• Research in energy efficient curing systems
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CONCLUSIONS
Growers have continually
been provided with tools that
ensure that the Zimbabwean
crop is grown in a sustainable
and responsible manner
Eucalypt wood
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THANK YOU!!
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ACKNOWLEDGEMENTS
1. TRB Management and Staff 2. CORESTA 2016
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