Investigations about cofiring of herbaceous biomass in an … · J. Judex, S. Daniele, J.-L. Hersener, S. Biollaz, P. Jansohn presented by Tilman Schildhauer. 2 Johannes Judex, 18.5.2009

Johannes Judex, 18.5.20093rd Freiberg Conference on IGCC and XtL Technologies, May 2009, Dresden

Investigations about cofiring of herbaceous biomass in an

Integrated Gasification Combined Cycle

J. Judex, S. Daniele, J.-L. Hersener, S. Biollaz, P. Jansohn

presented

by

Tilman Schildhauer

Johannes Judex, 18.5.20092

Motivation

•

Background: increasing electricity demand, but shutdown of old nuclear power plants in Switzerland• Using biomass for CO2

reduction and improved sustainability• Limited biomass resources• Testing grass/hay as additional bio fuel for power production via B-IGCC


Structure of the presentation

• GIS analysis (availability)• Gasification experiments with grass as fuel (gas quality)•

Combustion experiments with product gas-natural gas mixtures

(combustion characteristics)

availability





(combustion characteristics)

gas quality

availability





(combustion characteristics)combustion

characteristics

gas quality

availability


GIS analysis

• Base material (Swiss „Areal Statistik“): grassy

grounds• Filters: tilt, orientation, elevation, precipitation, exposition• Restrictions: only

minor

soil

quality

(no competition

energy

vs. food!)

each circle contains 32 ktdry substanceper year of herbaceous material


10 : 90 %LHV biomass to natural gas IGCC: size, efficiency

6000 operating hoursNG : Biosyngas10% : 90% by LHV45% : 55% by gas

volumeLHV mixed gas 21 MJ/m3

37 MWel total


Gasifcation of grass: trace species in the fuel

0

5

10

15

20

Ca K Mg Na Ba S Si

[g/k

g]

hay wood


►Cofiring fraction ~ 45% ►dilution factor 0.65►Volume increase during combustion (λ = 4 incl. secondary air) ► 5.7

Fuel quality requirements by GT

http://ec.europa.eu/

Element Limit average lit. Current mixtureK, Na < mg/m3 0.27 0.05V,< mg/m3 0.01 0.0001Ca, < mg/m3 0.04 0.002Ba, < mg/m3 NA 0.006P, < mg/m3 NA 0.006Cd, < mg/m3 NA 0.0001


Gasification experiments in bubbling fluidised bed

• Continuous operation for grass and air• Accumulation of ash in the bed• Variation of bed materials, λ, T, ..• Conversion, trace elements and slagging

grass pellet container

filter

air

bubblingfluidised bed

flare


Sampling and measurements

continuouswet sampling

raw gas permanent gases

solvent, tars, particles (99%)

Micro-GC

ICP-OES

filtersolvent

• Continuous operation for grass and air• Accumulation of ash in the bed• Variation of bed materials, λ, T, ..• Conversion, trace elements and slagging


Gas species (micro-GC) and metal traces (ICP-OES)

12:00:00 15:00:00 18:00:000

20

40

60

clock time

Con

cent

ratio

n, %

vol

N2

CO2H2

CH4

CO

C2H6

12:00 15:00 18:0010-6

10-4

10-2

100

clock time

Con

cent

ratio

n, μ

g/l ga

s

KNaBaPCaCdV

LHV 4.7 MJ/m3

Fuel dried hayBedmat. SiO2

Temp. 700°CPress. ambient


Optically accessible combustion test rig (LIF, chemoluminiscence)

Air flow rate: max. 270 g/sAir preheating temperature: max. 823 K Pressure: max. 30 bar Thermal power: max. 400 kW

Syngas / Air

To ICCD CameraTo PMs Array


Combustion chraracteristics: turbulent flame speed

• Co-firing looks achievable for a GT requiring only minor modifications• A fully fuel flexible engine represents still a major challenge

Turbulent Flame Speed

0

1

2

3

4

5

6

7

8

1650 1850

adiabatic flame temperature [K]

turb

ulen

t fla

me

spee

d [m

/s]

CH4H2-CO-CH4 20-20-60H2-CO 33-67H2-CO 50-50

Increasingsyngas

fractionIncreasing

syngas

fraction


NOx emissions depend on gas mixture and temperature

Lower NOx for co-firing mixture: Different pathway for Hx

Cy

oxidation

CH 4co-firin

g syngaspure syngas


Conclusions

►Grass is an available fuel for gasification►Grounds are possessed by mostly private persons►Amount in CH is significant but the security of supply is critical

►Gasification experiments proved stable operation at certain conditions►Contaminants in the gas phase are below the limits►Ammonia content in syngas

< ca. 450 ppmv

to limit NOx

►Combustion with proposed mixtures (co-firing 10% of LHV) is possible with only minor adaption of burner and chamber


Thank you for your attention


Gas mixture composition


BFB in detail

(1)

Fuel

storage(2)

rotary

feeder(3)

feeder(4)

auger

(water

cooled)(5)

inlet

gasification

agent(6)

reactor(7)

freeboard(8)

sampling

ports(9)

cyclone(10)

flare(11)

warm gas particle

filter

1

2

45

36

7

89

1011


Flame Speed

Laminar Flame Speed

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

1650

1850

adia

batic

flam

e te

mpe

ratu

re

[K]

laminar fame speed [m/s]

CH4H2-CO-CH4 20-20-60H2-CO 33-67H2-CO-N2 40-40-20H2-CO 50-50

Normalized Turbulent Flame Speed

0.00 2.00 4.00 6.00 8.00 10.00

1650

1850

adia

batic

flam

e te

mpe

ratu

re

[K]

turbulent flame speed factor wrt CH4

CH4H2-CO-CH4 20-20-60H2-CO 33-67H2-CO-N2 40-40-20H2-CO 50-50

Depending on their hydrogen-content the fuel mixtures have the ability to propagate faster, independently on the temperature

The ability to propagate faster, depends on the temperature; the effect is due to the

different physical properties of H2

• co-firing looks achievable for a GT requiring only minor modifications• a fully flexible engine represents still a major challenge


Experimental matrix

green: stable

process

yelllow: unstable

process

red: not conducted

because

of risk

of slagging

gray: not yet

conducted

dolimite: tensile

strength

is

too

weak

for

fluidized

bed

gasification

(Mohs

hardness

4)

SiO2: shows

melting

behaviour

at 750°C because

of alkali

influence

Al2O3: unfavorable

carbon

conversion

Olivin: NaN

dolomite700°C

750°C

800°C

SiO2

Al2O3

Olivine

0.17

0.20

0.25

ER

Documents

Investigations about cofiring of herbaceous biomass in an … · J. Judex, S. Daniele, J.-L. Hersener, S. Biollaz, P. Jansohn presented by Tilman Schildhauer. 2 Johannes Judex, 18.5.2009