8:15-10:00 Production
• Raw materials
• Equipment
• Quality issues
10:00-10:15 Coffee/Tea break
10:15-12:00 Use of pellets
• Transportation
• Storage types
• Boilers and burners
12:00-13:00 Lunch
13:00- Visit to wood pellet heating plants
Wood pellets day:
Some facts about wood pellets
• Newly discovered renewable fuel
• Diameter 6-10 mm and length 10-30 mm
• Bulk density in average 650 kg/bulk m3
(ca. 1,5 m3/ton)
• Low ash content with pure wood pellets, ca.
0,5 %
• High energy content, 4,7 kWh/kg
(2,1 kg pellets=1 l light oil=10 kWh)
Why pellets?
Why to refine shavings, saw dust
etc?
- More demand for by-
products
better price of by-products
more profitable
operation
- Easy to transport
- Clean and easy
combustion
Wood pellets
• main materials are shavings, cutterdust and
sawdust
• material has to be dry before pressing
(moisture content preferably <15%, optimum
~12%)
• many different tree species can be pelletized,
although coniferous are often considered to be
best / easiest
• mixture of species is normal situation (>50%
coniferous, <50% deciduous)
Raw materials
Other pellets for energy purposes
• Bark
• Peat
• Reed canary grass, straw, hay, grain etc.
Raw materials
Different steps in pellet production:
- Screening of incoming material
- Drying
- Separation of irrelevant materials
- Milling
- Mixing, steam addition
- Pressing
- Cooling
- Screening
- Packing
Pellet production process
- Determines the price level
- particular criterias for I and II class pellets
- When producing pellets, the end user must be
known (=markets)
- small households need I class pellets
- big power plants can use II class (bulk)
pellets
- Affects on many different things:
- transportation, burner type and
adjustment, ash behaviour, emissions
Quality of pellets
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Bulk pellets are transported for small
households in trucks with pneumatic
equipment
• most common way in Finland and Austria
• Pellets in big bags (normally 500 kg) or small
bags (16-20 kg) are transported by truck with
loader, or customers pick up the bags with
trailer
• common way in Sweden
Transportation
Transportation
Refining saw dust into pellets brings logistical
benefits
- It is possible to have large scale
production for export markets
- It is possible to offer a substitute for oil
• Important new sectors of business in pellet
production and in equipment production
• No loss of jobs in transportation sector
• Wood pellets are suitable for heating one-
family houses, farms, block buildings…
• They are also used in different size heating
and power plants
• At big power or heating plants, when using
pulverized combustion, the pellets are crushed
prior to feeding
• Conversion techniques for almost every
purpose can be found (even wood gas
applications etc.)
Using pellets
Using pellets
• The situation in some countries:
• Finland, ca. 4 500 users
• Sweden, ca. 1 000 000 users
• Germany, ca. 45 000 users
• Future visions for 2010, Finland as an example:
• the share of pellet heating in new houses 30 %
• 25 000 houses with pellet heating
• the potential is big: ca. 250 000 one-family
houses with oil heating
Using pellets
Storage solutions and conveyors:
Big outside silo for pneumaticfilling (note the checkingdoor)
Using pellets
Storage solutions and conveyors:
Pellet silo forhouseholds(horizontalposition),pneumatic filling
Using pellets
Pellet boilers and
burners:
-”Skandinavian type”
- Boiler and burner
are separate units,
possible to change
separately
Using pellets
Pellet boilers and
burners:
- ”Middle European
type”
- Boiler and burner
are one compact
unit, sold always
together
• The production is a complicated process
•The equipment needed are expensive
• The skills needed do not come from a quidebook
• The early stage requires special knowledge of
raw materials, equipment and markets / end use
Difficult entering of markets
• The EU wide standard for biofuels is not yet fully
operating
• Undeveloped markets of heating equipment
• We have not enough research results to promote
the markets
• Especially about the emissions
Problems with pellets
• Pellets started to come less than 10 years ago
• One pellet mill (Vapo Oy, municipality of Ilomantsi)
• Capacity ca. 70 000 tn/a, recent investments
• Users are mostly private houses and municipalities,
effect range 5-500 kW (almost 20 over 50 kW centres)
• Interest in pellets is strongly rising, due the high oil
and electricity prices
Pellets in North Carelia