Properties of wood pellets

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Main physical properties of sawdust pellets

This is an annex of our pellets file.

A) General Properties

- Raw material: untreated sawdust.
- Calorific value, PCI: between 4,5 and 5 kWh / kg.
- Density of single granule: 1100 1300 to kg / m3 (the pellet sinks in water!)
- Bulk density: of 600 750 in kg / m3, about half of the density of granules (50% void volume).
- Energy Oil Equivalence: 2kg granules = 1 liters of oil
- Energy Equivalence City gas: 2 kg of pellets = 1 gas m3.
- Storage: equivalent bulk volume required compared to fuel oil: 3,5 times the oil volume, oil 1000L therefore require 3,5 pellet storage m3 (including security).
- Prices for bulk 1 2007 tonne delivered in France: about 200 €.

B) properties in detail and standards

Next use (industrial or individual installation) the wood pellets standards vary slightly. This is mainly due to greater tolerance industrial units fuel!

In other words: a 10kW of pellet stove operating intermittently is more sensitive to fuel quality 500kW a burner continuously operating!

At the moment (end 2007) only Germany and Austria have national standards.

Other European countries are in the process of setting a European standard CEN / TS 14961, which is more or less in line with German standards (DIN) or autrichiene (ÖNORM).

The CEN / TS 14961 provides the following general requirements:

a) For pellets intended for individuals

- Origin: wood not chemically treated.
- Moisture: M08 (- Durability: DU97,5 (which means that after sieving, see "To know more", 97,5% or more of the pellets must remain intact).
- Diameter: D06 or D08 (6 or 8 mm).
- Length: - Ash content: - Sulphur: - Nitrogen: - Close: - PCI:> = Q16.9 (either 16.9 MJ / kg or 4,69 kWh / kg)
- Bulk density MMV: BD650 (> 650 kg / m3)

b) For pellets for industrial means

- Origin: wood not chemically treated.
- Humidity: M10
- Sustainability: DU96,5
- Diameter: D06 or D08
- Length: - Ash content: - Sulphur: - Nitrogen: - Close: - PCI:> = Q16.9
- Bulk density MMV: BD600

More: CEN TS 14961 and properties of pellets in Europe


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