www.swedishexergy.com Conversion of Coal fired Power Plant to Biomass using Exergy Steam Drying Technology – A Case Study Swedish Exergy AB Gamla Rambergsvägen 34 SE-417 01 Gothenburg Sweden Tel: +46 31 51 3990 Fax: +46 31 51 7960 Email: [email protected]
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www.swedishexergy.com
Conversion of Coal fired Power Plant to Biomass using Exergy Steam Drying Technology – A Case Study
Stalowa Wola – Power Plant • The power plant is located in the town of Stalowa Wola,
Poland.
• There are three boilers and turbines.
• Coal is used as fuel.
• One of the boilers is converted from coal to bio-mass fuel.
• All required bio-mass shall be pre-treated, dried to 90% dry solids and fine milled before firring to wood dust burners. All coal dust burners have been replaced with wood dust burners.
• Stalowa chose most efficient drying system availabe in the market – Exergy Drying System.
• The project is in final stage.
• This presentation is about this project and Exergy drying technology.
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Stalowa Wola Power Plant, Poland
• Conversion of coal boiler to bio-mass
• 50tons/hour bio-mass drying
• Two stage drying – Exergy Air Stream Dryer followed by Exergy Steam Dryer – single line capacity 45 ton/hour bio-mass with 50% moisture content
Buy or Produce Bio-Fuel Advantages of production of bio-fuel at Power Plant: 1. Lower Price of produced bio-fuel compared to
wood pellets – better economy 2. Flexibility 3. Only one transport cost from green field/forest
to place of use. 4. This reduces use of diesel for transport and
thus lower CO2 emission. 5. Independence from wood pellet market price
variations.
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Different factors at the combustion of moist fuels.
higher moisture
content
lower combustion temperaturemore excess air
larger fluegas amount
more uncombusted
material
larger flue gas refining
equipmentlarger furnace larger flue gas duct
greater investmentinferior efficiency
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Distribution of losses and useful energy at the combustion of moist and dried fuel respectively (1 KG combustible dry substance)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
21% losses with water steam
14% losses with dry flue gases
from completely dry fuel
65% absorbed in the boiler
20 MJ
150°
150°
2%
13%
85%
Boiler
Boiler
60% moisture
50% excess air
10% moisture
20% excess air
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Distribution of losses and useful energy at the combustion of moist fuel and flue gas dried fuel respectively
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
21%
14%
65%
20%
12%
68%
100°C 150°C
Boiler
20% excess air
60% moisture
50% excess air
Boiler
Dryer
60% moisture
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Why Dry Bio-fuels?
•Less air and water vapour from furnace •Reduced CO2 emission •Reduced fuel consumption •Higher boiler capacity •Less combustible material remains in ash