New bioenergy schemes

Workshop on Assessment of Early Stage Technologies8 March 2004, Riga Technical University, Riga,Latvia

Research Manager Satu Helynen

VTT PROCESSES

Contents

1. Bundling of forest residues as a new method for wood fuel supply

2. Bioenergy concepts for utilities (power generation)

• Cofiring in existing PC (pulverised combustion) boilers

• two-stage crushing + new type of burners

• atmospheric gasification

• Fluidised bed combustion with supercritical steam values

3. Large scale CHP for communities and industry with versatile fuel supply

4. Small scale gasification CHP (<10 MWe) with high power-to-heat -ratio

VTT PROCESSES

1. Bundling of forest residues as a new method for fuel supply

Comm inution at plant Branches, tops and smalls trees are bundled after harvesting operations in stand or at roadside

Bundles are stored at roadside or at plant in piles

Bundles are transported with normal trucks to a power plant which has a crusher or a mobile crusher is used

Status of technology:

Bundler is installed on a normal forwarder/tractor/truck, 15-30 bundles/hour

Manufacturers in Finland: Timberjack has delivered about 30 units, Pinomäki (Pika RS 2000) 3 units, Partek Forest (Valmet WoodPac) 1 unit. During 2003 nearly 1 million bundles (1 TWh, 36 PJ) were used in Finland. Costs of bundles at plant (without crushing) typically 9 €/MWh (2.2 €/GJ).

Under development: feasibility to different local conditions and harvesting methods in different countries

VTT PROCESSES

Bundling of forest residuesOne bundle: 1 MWh (3,6 GJ), diameter 75 cm, length 3-4 m

Photos: Timberjack

VTT PROCESSES

2. Bioenergy concepts for utilities (power generation)

• Advantages of cofiring: • Low investment costs, because existing steam cycle is used• High power generation efficiency, typically over 40 % • Biomass can be utilised when it is available with moderate costs

• Cofiring in existing PC (pulverised combustion) boilers• new two-stage crushing (Joutsan Konepalvelu) + new type of burners

(Enprima)• no drying or milling of biomass needed -> low costs• technology needs demonstration in full scale

• atmospheric circulating fluidised bed gasification (Foster Wheeler)• ash of biomass can be separated• cleaning of product gas enables also the use of recycled fuels• technology without gas cleaning has been demonstrated

successfully in full scale (Lahti, Kymijärvi, since 1999) and with gas cleaning is under demonstration

VTT PROCESSES

LP s tea m

F ly ash

F ilte rs

M a in bo ile r fu rn ace

B ed m a te ria ls

C F Bga s if ie r

Recycled fue ls

Fue l feed system

M a in bo ile r fee d w ater

S orb ent

Gas coo ler boiler

Recycled fuel gasification plant

Atmospheric gasifiers replace coal by product gas from biomass in the main boiler

Foster Wheeler

Source: Energy Visions 2030 for Finland, VTT Energy

VTT PROCESSES

2. Bioenergy concepts for utilities (power generation)

• Fluidised bed combustion with supercritical steam values

500

600

700

800

900

1000

40 4535 50Efficiency, %

PFCFBOTSC

Pulverised fuelCirculating fluidised-bed

Once-through supercritical steam cycle

CFB

CFB

80% coal20% biomass

100% coal

PF

OTSC CFB

OTSC CFBOTSC PF

CO2 emission, kg/MWh (electricity)

•High steam values increase efficiency, >45% possible for cofiring of local coals and biomass

•Demonstration plant in construction in Poland, 460 MWe, (Foster Wheeler)

•Feasible share of each biomass has to be defined

•Next phase 800 MWe

VTT PROCESSES

GP S

R EF

Säh köKau ko läm pö

Peltob io-m assa t

H akku u-tähteet

H akku utä hte et

Turve

H iili

P ro sess i-läm pö

Kuo ri, pro sess i-jäte

C HP -vo im ala

Tehda s

3. Biomass based fuels are complemented by fossil fuels in large-scale CHP plants

Mill

Bark,Processresidues Process

heat Forestresidues

Agro-biomass

Coal

Power

CHP-plant

Districtheat

Forest residues

REF

Peat

GPS

VTT PROCESSES

Plant

Supplier

C om missioning

Fuels

(annual share)

Therm al pow er

Live s team

B oiler e ffic iency

Plant output

Em ission lim its

O y Alho lm ens K ra ft AbKvaerner P u lp ing O y2001PeatW ood fue lsC oa l and o il550 MW

194 kg /s, 165 bar, 545 C92%Elec tric ityProcess heatD istrict hea tSO

N O

Particles

O

2

X

240 MW100 MW

60 M W70 m g/M J50 m g/M J

30 m g/m n3

S u p e rh e a te r

S u p e rh e a te rs

C y c lo n e

F u rn a c e

L o o p s e a l A ir fa n A ir p re h e a te r

S te a m d ru m

F u e lfe e d in gs ilo s

Circulating fluidised-bed boiler plant

Maximum shares of different wood fuels have been defined for optimising operation and maintenance costs (fouling and corrosion) of the boiler. Fuel unloading for 30.000 trucks/a: automatic sampling, dust control, occupational health.

Next phase: demonstration of the use of reed canary grass, straw and other energy crops , improving control and optimisation systems.

Source: Energy Visions 2030 for Finland, VTT Energy

VTT PROCESSES

4. Novel Concept by Condens: fixed bed gasification, gas cleaning and enginesCapacity up to 3 MWe, efficiency of power generation 30-36 % depending on the

moisture content of the fuel (0 - 30 %)

VTT PROCESSES

Novel Demonstration plant under construction in Kokemäkistartup 2004/2005

motors

gasifier

- fuel demand 7200 kW- electricity 1800 kWe, district heat 4300 kWth- investment costs 4,5 M€

VTT PROCESSES

Possibilities for cost reduction of small biomass plants (3 MWe and 5 MWe with rotating grate boilers and steam turbines) with serial production

0

10

20

30

40

50

60

70

80

90

100

Custom tailored Series of 5 Tens of plants

Relative costs, %

Work

Materials

Project management

Planning

Source: Wärtsilä BioPower.

Several commercial plants 3-5 MWe under construction.