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Rotary kiln pyrolysis- First results of a 3 MW pilot plant
Michael Halwachs
4th International Freiberg Conference on IGCC & XtL Technologies
3-5 May 2010 Dresden, Germany
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
2
Overview
• About the project
• Balance of the
pyrolysis pilot plant
• Results
• Outlook
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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About the Project
Usage of agricultural residues (straw) for power generation is a widely unexplored source of energyCheap feedstockregional available in huge amounts
Fundamental idea: Co-firing of straw in an existing coal fired power station
Problem: high content of Chlorine (Cl) and Potassium (K) of the straw is harmful for boiler and heat exchanger of the power station
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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About the Project
Troubleshooting:
Split up of the biomass into a volatile fraction that can be used for co-firing and a char fraction by a pyrolysis process.
The undesired components (Cl, K, Na) should be concentrated in the char fraction.
Pyrolysis-pilot plant DürnrohrJacked rotary kiln reactor (3 MWth)
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Kohlekraftwerk Dürnrohr
•Austria’s biggest coal fired power plant
•built as a replacement for the Zwentendorf nuclear power station, a plant that was finished but due to a 1978 referendum never started up
•consists of two blocks electrical output of 405 MW (operated by Verbund Austrian Thermal Power AG) and electrical output of 352 MW operated by the Energie-Versorgung Niederösterreich (EVN) AG
•The plant is powered by black coal imported from the Czech Republic and Poland but it can also use natural gas as a fuel
•In 2004 a heating plant (largest such in Austria, at the time) using the dissipated waste heat was opened
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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About the project
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Flowsheet
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Operating figures
Fuel power of the rotary kiln reactor: 3 MW
Throughput of straw: ca. 600 to 800 kg/h
Pyrolysis temperature range: 450 – 630 °C
Residence time of the feedstock: 30 – 45 min
Pyrolysis gas characteristics
Content of pyrolysis oil (gravimetric): 40 – 200 g/Nm³
Content of pyrolysis oil (GC-MS): 30 – 100 g/Nm³
Dust and entrained char: 20 – 120 mg/Nm³
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Feedstock
Wheat straw (indoor stored)Wheat straw (field stored)Maize strawStraw pelletsSorghum strawReed strawPalm nut shellsMiscanthus strawActiprot
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Fuel SamplesS
traw
Pel
lets
Ree
d S
traw
Sor
ghum
Stra
w
Whe
atS
traw
Pal
mnu
tShe
lls
Mis
cant
hus
Stra
w
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Pyrolysis Char SamplesS
traw
Pel
lets
Whe
atS
traw
Sor
ghum
Stra
w
Ree
d S
traw
Pal
mnu
tShe
lls
Mis
cant
hus
Stra
w
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Balance of the plant
• Creating a model of the system• Process simulation tool IPSEpro (stationary
equation oriented flow sheet simulation)• Validation of measured data
Property Libraries (DLLs)
C-Programming IDE
Fig.: Structure of IPSEpro (SimTech, 2001)
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Part of the testing scheme
Straw
Variation of the pyrolysis temperature
Variation of the residence time
Actiprot
Variation of the pyrolysis temperature
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Straw
Fig.: Mass- and energy fractions of the pyrolysis products of straw controlled by the pyrolysis temperature
0
10
20
30
40
50
60
70
80
90
100
450 500 550 600
pyrolysis temperature [°C]
mass fraction [%
]
0
10
20
30
40
50
60
70
80
90
100
450 500 550 600
pyrolysis temperature [°C]
energy fraction [%]
char
pyrolysis oil
pyrolysis gas
char
pyrolysis oil
pyrolysis gas
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Actiprot
Fig.: Mass- and energy fractions of the pyrolysis products of Actiprot controlled by the pyrolysis temperature
0
10
20
30
40
50
60
70
80
90
100
450 500 550
pyrolysis temperature [°C]
mass fraction [%
]
0
10
20
30
40
50
60
70
80
90
100
450 500 550
pyrolysis temperature [°C]enrgy fraction [%
]
char
pyrolysis oil
pyrolysis gas
char
pyrolysis oil
pyrolysis gas
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
C H O N S Cl K
Elements
Separation in char, gas and oil
pyrolysis oil
pyrolysis gas
char
Separation of the chemical elements
Fig.: Separation of the chemical elements in pyrolysis gas, pyrolysis oil and char for a pyrolysis operation of indoor stored straw.
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Efficiency
• Chemical efficiency
0.0
0.2
0.4
0.6
0.8
1.0
450 500 550 600
pyrolysis temperature [°C]
chem
ical efficiency [1]
straw acti‐prot
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Efficiency
Sankey-diagram for straw pyrolysis for the case of energy supply by pyrolysis gas, energy flows [kW]
Efficiency
Pyrolysis process 0.48
Coal fired power station Dürnrohr
0.42
Generated electricity by straw
0.2
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Conclusions
The process works technically correct
The gaseous product is suitable for co-firing in a coal fired power plant
The undesired components (Cl, K) are concentrated in the char fraction
• Efficiency is significantly higher than the electrical efficiency of smaller biomass fired power stations or CHP systems.
Approximately 50 % of the energy in the feedstock can be provided for co-firingFurther investigations on usage of “biochar”More Fuels (e.g. sewage sludge, residues from agricultural and paper industry)
04.05.2010
Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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Outlook
• Connection of the pyrolysis process to the coal fired power plant.
Scenario 1: 1 x 30 MW (one rotary kiln reactor)Scenario 2: 3 x 30 MW (three rotary kiln reactors)
Fig.: Scenario 1
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Rotary kiln pyrolysis - First results of a 3 MW pilot plant Michael Halwachs
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End