Wood

Pelleting

Technology

BÜHLER

Stefan Lescae CH – Uzwil, June 2006

► Use of wood pellets as a solid fuel

� common wood pellet sizes: 6 mm (Austria, Germany), 8 mm (Scandinavia)

� burned directly at the stove (e.g. Austria)

� pelletized for transport reasons (volume reduction) (e.g. Sweden)

• spec. volume (raw material): app. 5 – 20 l/kg

• spec. volume (wood pellets): app. 1.5 – 1.7 l/kg

• pellets are transported to large power plants and are ground again due to

burning properties

► Use of wood pellets for cat litter

Why Wood Pelleting?

Stefan Lescae CH – Uzwil, June 2006

Energy Aspects of Wood Pellets

0

2000

4000

6000

8000

10000

12000

14000

Wood

pellets

Peat lutro Wood

lutro

Brown

coal

Hard coal Oil Natural

gas

Net heat of combustion / kWh/t

Lutro = air dried

Energy for production of wood pellets:• 3 - 20 % of net heat of combustion

Stefan Lescae CH – Uzwil, June 2006

0

200

400

600

800

1000

1200

1400

1600

Wood pellets Heating oil Natural gas

Energ

y h

eating c

osts

(household

) for

34200 kW

h / E

uro

• Calculation done for Germany autumn 2002

• Wood pellets: 0.17 € / kg

• Heating oil: 0.37 € / kg

• Natural gas: 0.42 € / m3

Fuel Costs

Stefan Lescae CH – Uzwil, June 2006

Emissions from the Combustion

of Wood Pellets

0

50

100

150

200

250

300

wood pellets heating oil natural gas

SO2

Nox

Fly ash

CO

CO2

Em

issio

ns o

f com

bustion / m

g/m

3 Values based on specific stovesCO2 neutral

Stefan Lescae CH – Uzwil, June 2006

Net Emissions from the Combustion of

Wood Pellets

0

50

100

150

200

250

300

wood pellets heating oil natural gas

SO2

Nox

Fly ash

CO

CO2Net E

mis

sio

ns / m

g/m

3

Values based on specific stoves

Wood pellets are

CO2 neutral

Stefan Lescae CH – Uzwil, June 2006

Stefan Lesca

eCH –Uzw

il, June2006

Fore

st A

rea o

f Specific

Countrie

s

0

10

20

30

40

50

60

70

Japan

Finland

Slovenia

Sweden

Estonia

Canada

Russia

Latvia

Slovakia

Austria

Bulgaria

Czechia

USA

Germany

Switzerland

Romania

Poland

Portugal

France

Norway

Spain

Belgium

Fore

st A

rea / %

Political Motivations for Wood Pellets

Climate protection, Reduction of greenhouse gas CO2

� EU: promotion of renewable energy sources

� Kyoto protocol

� Danish energy policy: reduction of CO2 of 20 % (2005 – 1988)

�….

Security of energy supply� Green paper: European strategy for the security of energy supply

�….

1

2

Stefan Lescae CH – Uzwil, June 2006

Wood Pellets in Future

F U T U R E D E M A N D O N W O O D P E L L E T S F O R F U E L IN E U R O P E

N A T IO N A L

R E G U L A T IO N S

A N D L A W S

C O N S U M E R

B E H A V IO R

C O S T S F O R

W O O D P E L L E T S

W O O D P E L L E T S

F O R P O W E R

P L A N T S

E U G re e n

P a p e r

K y o d o

p ro to c o l

E U W h ite p a p e r

o n R e n e w a b le

E n e rg y S o u rc e s S u b s id ie s ,

ta x e s

C o s ts fo r

w o o d p e lle ts

C o s ts fo r

c o n v e n t io n a l

fu e ls

G re e n h o u s e

e ffe c t

E n v iro n m e n ta l

p ro b le m s

C o s ts fo r r a w

m a te r ia ls

In v e s tm e n t c o s ts fo r

w o o d p e l le t in g

O p e ra t in g c o s ts fo r

w o o d p e lle t in g

S u b s id ie s ,

ta x e s

E m is s io n s o f

w o o d p e lle ts

(C O 2 , a s h ,… )

S u b s id ie s ,

ta x e sC o s ts fo r

c o n v e n t io n a l

fu e ls

C o s ts fo r

w o o d p e lle ts

N a tio n a l

R e g u la t io n s

a n d la w s

C o m fo r t b y

u s in g w o o d

p e lle ts

A v a ila b il i ty o f r a w

m a te r ia ls

E n e rg y p r ic e s

S p a c e fo r

s to ra g e

N a t io n a l

re g u la t io n s a n d

la w s

S e c u r ity o f fu e l

s u p p ly

S e c u r ity o f fu e l

s u p p ly

Stefan Lescae CH – Uzwil, June 2006

Wood Pellets Process

Chipboard industry

Chipboards

wooden slats,

wooden boards,

parquet, furniture,…

Waste wood

Wood pellets (6mm, 8mm)Wood pelleting

process

By-products of wood processing

Wood industry (wood cutting, drying, sawing, grinding, planing,…)

Stefan Lescae CH – Uzwil, June 2006

Wood Pellets Process

Pretreatment (e.g. crushing, sieving,

heavy particle separator)

Drying

Grinding

Conditioning

Pelleting

Cooling

Sieving

Raw material

Wood pellets

Water and steamTransport

Storage

Control

Stefan Lescae CH – Uzwil, June 2006

Wetting

storageSieving

Storage

Bagging

Intake Sieving

Reduction

Pre Drying

Magnetic

GrindingPelleting

Drying

Wood Pellets Production

Stefan Lescae CH – Uzwil, June 2006

8490

101

133

0

20

40

60

80

100

120

140

3 shifts 7 days a week 3 shifts 5 days a week 2 shifts 5 days a week 1 shift 5 days a week

Productions costs depending onannual operation time / Euro/t

Production costs and

annual operation time

Stefan Lescae CH – Uzwil, June 2006

Wood Pellets Factoryexample

Raw Material Intake

Coarse GrindingSieving

Drying

Flat Store for Pellets

Pelleting

Grinding

Stefan Lescae CH – Uzwil, June 2006