Wood Pellet Production

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Wood Pellet Production

• George Estcourt

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Overview

• What are wood pellets
• Production process
• Production costs

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Wood pellets 101

• Compressed wood fibre
• 6-10 mm diameter
• Low ash lt0.5
• Sulphur free

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Wood pellets 101 cont-d

• Dry combustible material lt10 m.c. (w.b.)
• Consistent fuel quality 18 GJ/tonne(5 MWh/tonne)
• Easy to transport (flowable)
• Dense material (650-700 kg/m³)

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Production process

• Ideal Feedstock
• Dry wood shavings (untreated)
• Dry sawdust (untreated)
• Wet sawdust (untreated)
• Dry/Wet chip (untreated)
• Dry off-cuts (untreated)
• Radiata pine
• Other softwoods
• Hardwoods

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Stage 1

• Transport and Storage of feedstock
• Most feedstocks are bulky 150 kg/m³ (shavings)
• Wet feedstocks55 m.c. (wet basis)122 m.c.
  (dry basis)
• Half your material is water
• Most materials will not flow or move easily

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Stage 2

• Feedstock Preparation
• Dried down to approx 10 m.c. (wet basis)
• Particle size down to approx 1-mm thickness
  (chipper/hammer mill)
• Material needs to be contaminant free. No steel,
  stones, or dirt (screens/magnets)

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Stage 3

• Pelletising
• Conditioning addition of steam or other
  additives (lignin for hardwoods)
• Pressing 15-30,000 psi, 90oC
• Cooling and bagging (20kg or bulk)

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Pelletisation is not easy

• Not all species behave the same
• Softwoods are an easier feedstock
• Hardwoods quite often need lignin or binders
• Making a good pellet is a combination of
• Moisture content
• Particle size
• Lignin content
• Press design

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Small-scale operation 100kg/hr
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Costing of basic plant-100kg/hr

• Sawdust / shavings / chips feed bin 27,000
• Hammer Mill 24,000
• Sawdust auger 9,000
• Sawdust control bin, water andoil-dosing
  systems 18,000
• Basic Pellet Mill with 6.0mm woodpellet
  die 27,000
• Pellet bucket elevator 12,000
• 1.5 tonne Cooling/storage bin 15,000
• Manual / auto control panel 27,000
• Total, approximately (plus freight) 160,000

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Operating costs

• High person hours
• Site rental
• Electricity consumption
• Heat for drying (if required)
• Maintenance of plant
• Storage of wood pellets (under cover)

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Not ideal storage!!!
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It all depends

• Very site specific
• Feedstock material
• Access to waste heat for drying
• Is the market developed
• Do you have the skills required

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We can help!

• Through the Bioenergy Knowledge Centre (BKC), we
  can answer basic questions about pellet
  production
• We complete pre-feasibility studies around wood
  pellet production through the BKC
• Plan to invest in pellet testing facility to aid
  potential pellet producers
• Full-scale feasibility studies
• Access to industry experts

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Any questions?

• Visit Bioenergy Knowledge Centre
• www.bkc.co.nz
• Log a job
• 0800 bioenergy
• E-mail me
• george.estcourt_at_scionresearch.com