Wood Pelleting Process Buehler

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?


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


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


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


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 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


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


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,…)


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


Wetting

storageSieving

Storage

Bagging

Intake Sieving

Reduction

Pre Drying

Magnetic

GrindingPelleting

Drying

Wood Pellets Production


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


Wood Pellets Factoryexample

Raw Material Intake

Coarse GrindingSieving

Drying

Flat Store for Pellets

Pelleting

Grinding


Wood Pelleting Process Buehler

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