Solid biofuel quality and standards

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Solid biofuel quality and standards

• Bernard Rice

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CEN committees structures

• Technical committee 335 (2000)
• Solid biofuels
• Technical committee 343 (2002)
• Solid recovered fuels (CD waste etc)
• Aim develop EN standards to facilitate
  inter-state biofuel trading

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Standards measurement of physical properties

• Moisture content
• Calorific value
• Bulk density
• Particle size classification
• Pellet durability

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Standards measurement of chemical properties

• Ash content and melting point
• Nitrogen
• Potassium, sodium, chlorine
• Phosphorus
• Heavy metals

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CEN/TS 14961

• Solid biofuel specifications and classes
• Normative for wood chips
• Particle size classification, Moisture, Ash,
  Nitrogen
• Recommended for wood chips
• Nett calorific value, bulk density, chlorine

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Sampling. Initial planning (i)

• What analyses will be carried out?
• What size of sample is needed?
• Bulk density gt20 kg
• Size classification gt2 kg
• Other analyses lt1 kg

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Sampling Initial planning (ii)
Bulk sample
Sub-sample for bulk density, moisture. Put
moisture sample into sealed container
Dry (to 20)
Sub-sample for particle size
Sub-sample for ash, calorific value, chemical
analyses
Dry and grind
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Sampling Taking sub-samples from bulk

• Vital that final sample is representative
• Remove at least five sub-samples
• Sub-sample size at least 1 kg
• Select sub-sample removal sites carefully
• Use scoop or shovel

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Sampling Sub-sample mixing, splitting

• Mix sub-samples thoroughly
• Reduce final sample to required size by
• Quartering
• Riffling
• Other

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Particle size classification(manual or
mechanical)
63 mm
3.15 mm
16 mm
45 mm
Pan
8 mm
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Particle size classification
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Bulk density measurement

• Weigh 50-litre bin
• Fill with chips
• Drop three times
• Level off
• Weigh again

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Moisture measurement

• Sample size at least 300 g
• Be sure to avoid moisture loss before weighing
• If necessary, dry and weigh container
• Not more than 3cm layer in tray
• Place in oven _at_ 105oC until dry (16 hours)
• Moisture (weight change/initial weight) x 100

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Moisture content specifications
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Microwave??