the 12th european gasification conference · cofiring is an efficient way to use biomass...

THE 12th EUROPEAN GASIFICATION CONFERENCE March 10–13, 2014 Rotterdam, The Netherlands

Vaskiluoto CFB Gasificaton Plant

Juhani Isaksson, Valmet Power

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12 March, 2014 © Valmet | Author / Title 3

Valmet Power - gasification offering

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Product gas for

industrial kilns

• Sawdust, forest

residues, fresh wood,

bark

• 20 – 80 MWfuel units

• Typically includes a

dryer

• Dusty product gas

• Also other types of

kilns possible

Product gas for

power boilers

• Woody biomass,

bark, peat, straw…

• Superior electricity

efficiency

• (Existing) power

boilers

• 50 – 300 MWfuel

units

• Typically includes a

dryer

• (Gas filtering)

Product gas from

waste for power

production

• Waste-derived fuel

• High electricity

efficiency

• Typically a new gas

boiler

• Gas filtering -> clean

product gas

• 50 – 100 MWfuel units

or multiple units

connected to a boiler

Indirect

gasification of

biofuels

• Suitable for clean

biofuels

•Suitable for cases

HIGH HEATING VALUE

GAS is needed 8 SNG,

refinery feed motors)

Cofiring is an efficient way to use biomass

Example:100 MW of biofuel available at the district

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100 MW, fuel Small boiler,

efficiency 25 % 25 MW

green electricity

100 MW, fuel Large boiler,

efficiency 40 % 40 MW

green electricity

+

160 MW

coal electricity 400 MW coal

The final outcome is 60 %

more green electricity !

Valmet scope in Vaskiluodon Voima’s gasification project

Full scope services with total plant optimization

– Fuel receiving and handling

– Drying

– Gasification

– Boiler modifications

– Automation, electrification and instrumentation

Wet biomass

Existing PC boiler

Instrumentation,

electrification

and automation

Biomass receiving

and pre-handling Large-scale belt dryer CFB gasifier

140 MWfuel

Product gas

Dried biomass

VASKILUOTO GASIFICATION PLANT

Date Author Title INTERNAL 7

FUEL STORAGE

AND HANDLING

PC BOILER

CFB

GASIFIER

DRYER

Valmet CFB gasifier

CFB Gasifier

Size 20 – 140 (300) MWth

Fuel Biomass, waste

Gasification media Air

Operating

temperature

750 – 900 C

Operating pressure 5-30 kPa(g)

Product gas

heating value

3-7 MJ/nm3 (LHV)

8

Fuel feeding CFB reactor

Bottom ash removal

Cyclone

Product gas line

Product gas/

gasification air

- heat exchanger

Biomass dryer Vaskiluodon Voima

Vaasa, Finland

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Start-up 2012

Process Gasification (140 MW)

Materal Forest resudues (chips)

Size 274 m2 / 2 950 ft2

Layer type Single

Heat source Water/glycol-50%

73 - 85°C / 163 - 185°F

Capacity 10 metric tons/h

of evaporated water

Fuel Moisture vs. Gasifier output

Fuel moisture ( waste ) 20% 30% 40%

Gasifier max output 100 89 77

Waste fuel: HHV dry 22,5 MJ/kg, Ash 7,6%

CFB gasifier

Date Author Title 10

0

1

2

3

4

5

6

7

8

20 40

Ga

s h

ea

t va

lue

ho

t M

J/m

3n

Fuel Moisture

Gas heat value MJ/m3n hot ( incl. sensible heat )

Vaskiluoto Biomass Gasification plant

and the main experiences of the project

11.3.2013

Matti Tiilikka

Project manager

Vaskiluodon Voima Oy 11

Vaskiluoto 2

Investments:

‒ Boiler plant 1982

‒ Desulphurization plant 1993

‒ New turbine plant 1998

In technical terms, the plant is

fit for use until 2030

Main figures:

‒ Electricity output 230 MW

‒ District heat output 175 MW

Vaskiluodon Voima Oy 12

Vaskiluoto Power Plant

Main project drivers

Main drivers for the project:

To replace large amount (25-40%) of coal with renewable CO2-neutral fuel.

‒ The gasification plant will be run on full capacity and coal firing will be

reduced on boiler part loads.

To extend the lifetime of the existing power plant unit

To achieve capability to use multiple fuels (fuel cost optimization)

To guarantee a cost-effective district heating solution

Investment cost and benefits

Total investment cost 40 M€. State investment subsidy 10,8 M€

(Ministry of Employment and the Economy)

Cost savings:

‒ Reduction of CO2-emission cost, reduction of CO2-emissions

up to 230 000 t/yr.

‒ Feed-in tariffs of renewable energy

‒ Reduction of the environmental taxes of district heating

Other benefits:

‒ Low total cost compared with the construction of a totally new biofuel

power plant

‒ Gasification compared with wood pellet firing: higher cost of pellet

production (around +50%) and pellet milling is avoided

‒ Local fuels - Positive effects to the local economy, 15 M€/a.

• The new activities will employ 100 people in fuel logistics

Vaskiluodon Voima Oy 14

Project implementation

Main Schedule

Environmental permit 10.8.2010

Binding promise of the investment subsidy 8.4.2011

Contract with Metso Power Oy 6.5.2011

Start of the foundation work 1.9.2011 (4 months)

Start of the equipment installation 1.4.2012 (11 months)

Planned five weeks’ outage in August 2012 (15 months)

Start of test runs October 2012 (17 months)

Start of the commercial use January 2013 (20 months)

Vaskiluodon Voima Oy

Project experiences

Total project costs did stay in the frames of the budget

Installation time:

‒ The time schedule was very tight. That pressed final installation work

to late autumn and made the test running period quite challenging.

‒ Even so, the boiler modifications were made as planned during

5 weeks’ outage.

‒ The site safety was organised fine and there was only one minor

accident on site.

Test run:

‒ Only minor effects on PC-boiler operation, no boiler trips – great!

‒ The fuel unloading pockets were designed with high separating walls and

some types of trucks have had difficulties to operate between those walls.

‒ In the fuel sampling system there has been jamming with wet and cold peat.

‒ Temperature differences on the body material of air heaters have caused

distortion and damaged bellows of the gas ducts.

16 Vaskiluodon Voima Oy

Operation experiences

There has been no instabilities in the boiler evaporator.

NOx -emission level has been under the limits of environmental permit

(500 mg/m3(n)) – after the modification the emission level is around 350

mg/m3 and has been around 400 mg/m3 last year.

The warranty values are likely to be fulfilled. Warranty tests will be

carried out in March 2013.

The dyer has functioned fine. We have seen that investment quite

successful also because biofuels have been abnormal wet this year.

The potential risk of the hot corrosion of the superheaters was noticed

and therefore a theoretical study was made by Metso. As a result it was

decided to keep the rate of biofuel always under the rate of coal.

17 Vaskiluodon Voima Oy

12 March, 2014 © Valmet | Author / Title 18

Gasifier load

(70 – 132 MW)

Live steam pressure

Temperature and flow

Load following with coal

Reduction for nights

NOx content of boiler flue gases

12 March, 2014 © Valmet | Author / Title 19

200

225

250

275

300

325

350

375

400

425

450

0 % 10 % 20 % 30 % 40 % 50 % 60 %

NO

x m

g/N

m3 6

% O

2

Gasifier share of total fuel input

High O2 Low O2

SO2 content - before sulphur removal

12 March, 2014 © Valmet | Author / Title 20

0

50

100

150

200

250

300

350

400

450

500

550

5 % 10 % 15 % 20 % 25 % 30 % 35 % 40 % 45 % 50 % 55 %

SO

2

m

g/N

m3 6

% O

2

Gasifier share of total

First year availability

12 March, 2014 © Valmet | Author / Title 21

0.0 % 20.0 % 40.0 % 60.0 %

Fuel handling

Flame detection

Burner impeller damage

Air preheater imbalance

Air damper leakage

Torch test mailfunction

Distribution of causes for unavailability (total 3 %)

First operational year 2013/2014 availability was 97 %

Dryer (Titanic)

We are very pleased about the final results of this project and like to thank all

our suppliers for the fine co-operation!

22 Vaskiluodon Voima Oy

For further information contact: juhani.isaksson@valmet.com