Waste wood gasification in an allothermal gasifier

A. van der Drift

C.M. van der Meijden

Presented at the 19th European Biomass Conference and Exhibition (EU BC&E), ICC Berlin, Germany (Conference 6-10 June 2011 - Exhibition 6-9 June 2011)

ECN-L--11-061 June 2011

Waste wood gasification

in an allothermal gasifier

Bram van der Drift, Christiaan van der Meijden

2

ECNbusiness units

Solar energy Wind energy

Policy

Studies

Efficiency &

Infrastructure

Biomass

Biomass conference,

Berlin, 6 June 2011

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CONTENTS

1. Why development of a new gasifier?

2. Working principles Milena technology

3. 30 kWth Lab scale installation

4. 800 kWth Pilot plant

5. Results demolition wood tests

6. Demo plant Alkmaar

7. Conclusions

Biomass conference, Berlin,

6 June 2011

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WHY DEVELOPMENT of MILENA GASIFIER?

• MILENA produces a medium calorific value gas that can be

efficiently upgraded into Bio-SNG or can be used in CHP’s for

heat and electricity production

• Cold gas efficiency for MILENA gasifier is higher than of

competing processes. Waste is minimized (no char containing

char)

• High efficient production of SNG

• High initial CH4 yield.

• Limited dilution of product gas with N2

• High overall efficiency in CHP applications

• Limited adaptation to gas engine because of relatively high

calorific value of gas

Biomass conference, Berlin,

6 June 2011

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OVERALL EFFICIENCIES WOOD-to-SNG

calculations for large-scale plants

Biomass conference, Berlin,

6 June 2011

53%

70%

58%

67%

64%

54%

50%

55%

60%

65%

70%

75%

Entrained Flow CFB Indirect

effic

ien

cy

BioSNG

BioSNG and net power

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4, p

p 3

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-311

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01

0.

EFFICIENCIES MILENA – CHP calculations of 4 MWe plant

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6 June 2011

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ECN MILENA

gasification technology

• MILENA indirect gasifier

• developed for high efficient

SNG-production

• MILENA-exit:

- 11-15 vol% CH4

- 20-25 vol% H2

- 30-35 vol% CO

- 10-15% vol% CO2

- 6 vol% C2Hx, tars, N2, ...

Biomass conference, Berlin,

6 June 2011

MILENA CHARACTERISTICS

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• Medium calorific gas, low N2

• Complete conversion, no carbon in ash

• High CH4 content, suitable for Bio-SNG

production

• Reactor concept is suitable for scale up

(> 100 MWth) and pressurized

operation.

• High tar content

Biomass conference, Berlin,

6 June 2011

MILENA, 5 kg/h

lab-scale facility

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LAB-SCALE MILENA + OLGA + SNG FACILITY

MILENA

gasification OLGA

gas cleaning methanation

• First MILENA tests in 2004

• First integrated tests in 2006

Biomass conference, Berlin,

6 June 2011

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MILENA 30 kWth LAB-SCALE FACILITY

• More than 2000 hours of operation in gasification mode

• Tested fuels: wood, sewage sludge, grass (not successful)

and lignite

• Bed materials: olivine, dolomite, and sand

• Interesting results:

No agglomeration problems with wood as fuel

Co-gasification of lignite reduces tar content significantly

Transports of O between combustor and gasifier when

olivine is used as bed material

Biomass conference, Berlin,

6 June 2011

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MILENA PILOT PLANT

• Thermal input 160 kg/h (800 kW)

• In operation since 2008

• Connected to OLGA tar removal in

2009

• Design fuel: wood

• Gasifier / riser diameter: 0.2 m

• Combustor diameter: 0.8 m

• Total height: 8 m

Biomass conference, Berlin,

6 June 2011

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MILENA PILOT TEST FACILITY

•Biomass

•Flue gas

•Steam •Tar + dust

•White ash

•Burner

•Boiler

•OLGA

•Flue gas

•Wet

•Scrubbing

•MILENA

Biomass conference,

Berlin, 6 June 2011

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MILENA PILOT PLANTstatus

• In operation since 2008, connected to OLGA

• Autumn 2010 duration test on demolition wood (250 hours)

• Fuel: wood, throughput between 120 and 160 kg/h

• Fluidization agent gasifier: Steam (15 kg/h) or Air (20 Nm3/h)

• Bed material -> Sand / Olivine

• Gas composition similar to lab-scale installation (tar content approx. 40 gram/Nm3

• OLGA can handle high tar load

• Improvements:

Bottom ash discharge system is modified / extended to remove glass and prevent accumulation of large particles

Piping between MILENA and OLGA is replaced, because it was designed for previous gasifier, local cold spots caused problems

Biomass conference, Berlin,

6 June 2011

DEMOLITION WOOD

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• painted

• incl. plywood and MDF

• incl. glass

• milled/sieved for pilot

test

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6 June 2011

PRODUCER GAS COMPOSITION

MILENA pilot tests

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6 June 2011

DEMOLITION WOOD TEST RESULTS

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• Gas composition main compounds

according expectation / similar to clean

wood

• No major difference in tar production.

OLGA is able to remove tar sufficiently

• Bottom ash discharge required to prevent

accumulation of glass in the gasifier

• High concentrations of NH3 and HCN in

producer gas, removal required

• Bag house filter is sufficient for cleaning

flue gas, possible additives required to

lower HCl concentration in flue gas (50

ppm)

Bottom ash

after sieving

Biomass conference, Berlin,

6 June 2011

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11.6 MWth MILENA Bio-SNG DEMONSTRATION

• Location: Alkmaar

• Fuel: wood approx. 3000 kg/h - 25wt%

moisture

• Basic engineering MILENA + OLGA +

Gas Engine done in 2010 (ECN +

Dahlman)

• Changes in subsidies -> Gas Engine will

be replaced by methanation unit

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6 June 2011

• New application for bio-SNG production at the end of 2011

• Probably new location

• Methanation technology still undecided.

• Extension of consortium with additional partners interested in

demonstrating Bio-SNG technology

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MILENA DEMO PLANT ALKMAAR

MILENA

gasifier

OLGA tar

removal

Biomass conference,

Berlin, 6 June 2011

OUTLOOK

• Strong interest in Bio-SNG production from commercial

partners, consortium is growing

• Bio-SNG demo will part of Biomass Expert Centre located in

Alkmaar -> possibilities for testing innovative processes using

real biomass producer gas

• Cooperation with Thermax to realize 1 MWe demo in India

using Soya stalk

• Preparations / offers for Several Bio-CHP’s using demolition

wood, typically 2 – 5 MWe

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Biomass conference,

Berlin, 6 June 2011

CONCLUSIONS

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• Waste wood can be used as a fuel for the MILENA gasifier

• OLGA can handle the tars

• Sufficient bottom ash should be distracted to prevent

accumulation of glass, which will result in agglomeration

• Pollutants like NH3 and HCN will increase significantly

compared to clean wood, gas cleaning should be designed

for this

• At a typical scale of 1 – 10 MWe, the energetic efficiency

of a MILENA gas engine combination is significantly higher

than of a combustion system

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Berlin, 6 June 2011

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MORE INFORMATION

Bram van der Drift

e: vanderdrift@ecn.nl PO Box 1

t: +31 224 56 4515 NL 1755 ZG Petten

w: www.ecn.nl the Netherlands

publications: www.ecn.nl/publications

fuel composition database: www.phyllis.nl

tar dew point calculator: www.thersites.nl

IEA bioenergy/gasification: www.ieatask33.org

Milena indirect gasifier: www.milenatechnology.com

OLGA tar removal: www.olgatechnology.com

SNG: www.bioSNG.com and www.bioCNG.com

Biomass conference,

Berlin, 6 June 2011