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Pyrolysis in late medieval foundry processes Georgius Agricola, De Re Metallica Libri XII, MDLVI English translation 1912 by Herbert Hoover
Pyrolysis & Char Processes Fernando Preto CanmetENERGY, Natural - - PowerPoint PPT Presentation
Pyrolysis & Char Processes Fernando Preto CanmetENERGY, Natural - - PowerPoint PPT Presentation
Pyrolysis & Char Processes Fernando Preto CanmetENERGY, Natural Resources Canada Charcoal Production & Use Pyrolysis in late medieval foundry processes Georgius Agricola, De Re Metallica Libri XII, MDLVI English translation 1912 by
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Char Production How can we optimize char production?
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Pyrolysis Stages
Temperature Process (Overlap) Major Products Heat
<200ºC Drying H20 IN 230ºC-250ºC Depolymerization Acetic acid, Methanol, CO2, CO IN 250ºC-280ºC Torrefaction Extractives, CO2, CO IN 280ºC-500ºC Devolatilization Organics, Tars, CO2,CO OUT 500ºC-700ºC Dissociation/Carbonization CO, H2 IN >700ºC Gasification H2, CO IN
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Time to Complete Pyrolysis as f(size)
- X. Wang et al 2006
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5 10 15 20 25 30 35 40
Yield %
2.5 secs 5 secs 20 secs
Vapour Residence Time Liquid Gas Solid
Yields vs Residence Time
T=500 C
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Charcoal Yield as f(size)
- X. Wang et al 2006
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Product(s) Yield as f(Temperature)
- X. Wang et al 2006
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Product Distribution
A.V.Bridgwater
Mode Conditions Liquid Char Gas Fast pyrolysis Moderate temperature, short residence time 75% 12% 13% Slow Pyrolysis Low temperature, very long residence time 30% 35% 35% Gasification High temperature, long residence time. 5% 10% 85%
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Species Migration: S, N
- J. Hrbek et al 2006
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- J. Hrbek et al 2006
Species Migration: Cl, K
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Yield of Traditional Charcoal Processes
- Batch processes:
- Earth pits and mounds
>10%
- Brick, concrete, and metal kilns
20-25%
- Retorts
30%
- Continuous processes:
- Retorts (Lambiotte)
30-35%
- Multiple hearth reactors (Herreshoff)
25-30%
FAO Rinsing Retort
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Pyrolysis: Industrial Research in Canada
ABRI-Tech Airex Alterna Organic Power Titan Agritherm… ABRI-Tech Airex Agritherm Ensyn Dynamotive…
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Courtesy NREL
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Maximizing Charcoal Yield
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Maximizing Charcoal Yield
- Low pyrolysis temperature (<400ºC)
(but also lower fixed carbon content)
- High process pressure (1 MPa)
(higher concentration of pyrolysis vapor increases rate of secondary reactions)
- Long vapor residence time
(extended vapor/solid contact promotes secondary coke forming reactions)
- Low heating rate
(slower formation and escape of organic vapors)
- Large biomass particle size
(low thermal conductivity of biomass results in slow heat and mass transfer rate within particles)
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