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Eawag: Swiss Federal Institute of Aquatic Science and
Technology
Sandec: Sanitation, Water and Solid Waste for Development
Carbonization research at Sandec Solid Waste Management
Group
Imanol Zabaleta
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Outline
1. Slow Pyrolysis -Tanzania 1. Horizontal Reactor
2. Vertical Reactor
2. Hydrothermal Carbonization - Switzerland 1. Energy
efficiencies at mild conditions
2. Nutrient balance
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Construction and testing Horizontal reactor
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1. pyrolysis drum 2. pipe for initial pyrolysis gases 3a.
rotating knob
Slow Pyrolysis in Tanzania – Phase I (2013-2014)
3b. rotating and ejection handle 4. combustion chamber 5. brick
kiln
Externally heated
Tested with different local biomass
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Improving Energy efficiency of Horizontal reactor
Slow Pyrolysis in Tanzania –Phase II
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Constructing and testing a Vertical Reactor
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Slow Pyrolysis in Tanzania –Phase II (2015)
Simplification of “Abokobi Char Kiln”
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Comparison of reactors
Slow Pyrolysis in Tanzania –Phase II
0%
25%
50%
75%
100%
Cardboard (feedstock) horizontal kiln vertical kiln ARTI
kiln
Ash content Fixed carbon content Volatile content
Cardboard H.R V.R.
HHV [MJ / kgdb] 17.6 24.2 24.3
ER1 [-] 0.67 1.49 𝐸𝑅 1 =𝐸.𝑐ℎ𝑎𝑟𝑐𝑜𝑎𝑙
𝐸.𝑓𝑢𝑒𝑙
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o Local Tanzanian student MSc thesis
o Swiss Civil servant
o Objectives:
1. Improve energy efficiency
2. Improve handling system of the reactor
3. Test with two local feedstocks
Optimization of Vertical reactor
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Slow Pyrolysis in Tanzania –Phase III (2016)
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o Hydrothermal Carbonization (HTC)
Background
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Hydrothermal Carbonization at mild conditions
T 160-190oC
P 20-30 bar
RT 2 -10 hours
Wet Biomass
Gas
Process Water
Hydrochar.
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Energy efficient– so what?
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Hydrothermal Carbonization
in the range of (roasted) biomass and peat
similar characteristics to torrefied products (HHV: 20-24 MJ/kg,
VM: 55-65%, FC:
28-35%).
Benefits over raw biomass: Homogenized, richer in carbon and
energy density,
hygroscopic and grindability characteristics
Unsuitable for cooking
stoves (too high VM)
Suitable for combustion
in industrial burners or
incineration plants
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Nitrogen - Distribution of N between Process Water and
Hydrochar
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Hydrothermal Carbonization
60% of TN is mainly recovered in the Hydrochar
Most of Water extractable as NO3.
Phoshorus - Distribution of P between Process Water and
Hydrochar
50 – 70% of TP is mainly recovered in the Process Water
50 – 70% of TP in hydrochar is Water extractable PO4.
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Thank you for listening!
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Questions?
mailto:[email protected]:[email protected]
