P. Jaud EDF R&D

Operation of the CFB boiler

Start of the CFB boiler in 1996 operated by SOPROLIF,

4 fuels were burned at Provence 250 MWe CFBProvence Lignite (design fuel, but local mine closed in 2003).

Lean coal (Gard, France), low volatile bituminous coal not far from semi anthracite

Imported coal, low ash and sulfur content, high volatile bituminous coal

Delayed petroleum coke, with a high sulfur content

SNETSNET

Electricity Electricity generation generation

contractcontract

EDF/CNETEDF/CNETCdF IngenierieCdF Ingenierie

Engineering Engineering ContactContact

Project Financing Project Financing advisoradvisor

Banque IndosuezBanque Indosuez

ENDESASNETEDF

EDFEDF

Steam Steam contractcontract

SNETSNET

Operation Operation contractcontract

HBCMHBCM

Coal supply Coal supply contractcontract

SuppliersSuppliers

Equipment Equipment contractscontracts

SOPROLIFSOPROLIF

Shareholders :

SNETSNET

Electricity Electricity generation generation

contractcontract

EDF/CNETEDF/CNETCdF IngenierieCdF Ingenierie

Engineering Engineering ContactContact

Project Financing Project Financing advisoradvisor

Banque IndosuezBanque Indosuez

ENDESASNETEDF

EDFEDF

Steam Steam contractcontract

SNETSNET

Operation Operation contractcontract

HBCMHBCM

Coal supply Coal supply contractcontract

SuppliersSuppliers

Equipment Equipment contractscontracts

SOPROLIFSOPROLIF

Shareholders : -In 2004, ENDESA became majority shareholder of SNET,

- In 2008 SNET took over SOPROLIF and EON bought ENDESA shares in SNET,

- In January 2010 EON took over 100 % of SNET.

Characteristics of the fuels burnt at Provence 250 MWe CFB

Fuel analysis Provence lignite(Gardanne Coal)

Petroleum Cokeat ship unloading

Imported Coal Gard Coal

Moisture 9.9 % 5 to 7 % 9 % 5.7 %

Ash (dry basis) 30.0 % 0.5 to 0.7 % 15.4 % 28.0 %

Volatile matter (dry basis) 43.5 % 9 to 10 % 25.6 % 15.0 %

Carbon (dry basis) 49.5 % 80 to 87 % 71.2 % 63.2 %

Hydrogen (dry basis) 3.2 % 3.1 to 3.4 % 3.9 % 3.9 %

Oxygen (dry basis) 11.9 % 1 to 7 % 7.0 % 2.1 %

Nitrogen (dry basis) 1.3 % 1.3 to 1.7 % 1.7 % 1.8 %

Sulfur (dry basis) 4.2 % 6 to 8 % 0.8 % 1.3 %

Low Heating Value (MJ/kg)(dry) 18.4 31.4 to 32.2 25.1 to 25.4 16.5

Fuels

Very few operation set points have been modified to burnt different fuels

Provence lignite

Petroleum coke

Imported coal

50% Petroleum coke 50% Imported coal

Furnace temperature reference +10°C +10°C +10°C

O2 at boiler outlet (before air heaters)

3% 4.0% 3.7% 3.7%

Temperature for feeding fuel without oil support

reference +30°C +30°C +30°C

Furnace temperature: Objective: reduce unburned loss

O2 at boiler outlet (before air heaters): Objective: compensate for the lower flue gas volume

Operation set points

General behaviour of the boiler

Main performance data

12% lower pressure drop, but satisfactory heat transfer rate in the furnace remains similar since higher temperatureNo need for ballast injectionBoiler efficiency:

- Impact of unburned loss in the fly ash and limestone calcination- Impact of the sulphation credits: good results of Provence lignite and blend of petroleum coke + imported coal

Provence Lignite

Petroleum coke

Imported coal

50% petroleum coke 50% imported coal

Mean furnace temperature difference Reference +47°C +26°C +40°CFurnace upper part pressure drop Reference -10% -15% -12%Boiler efficiency NFE 32.130With sulphation credits

92.6%94.8%

91.0%93.7%

91.6%91.6%

91.3%93.3%

Unburned carbon in fly ash (% of fly ash)

0.5% 3.7% 7.7% 5 to 7 %

Pollutant emissions

Pollutant emissions at stack

Regulation limits: SO2 : 400 mg/Nm3, Nox: 500 mg/Nm3

Desulphurisation

Petroleum coke: very good desulphurisation rate: 97%

Low Ca/S: <2.5

explanation: significant conversion of SO2to SO3 in the presence of Va

Blend: Ca/S higher due to change of limestone, optimisation necessary

Combustion of the blend

CO content: quite low

NOx content: low

Blend: good compromise

Units (dry 6% O2 )

Provence lignite

Petroleum coke

Imported coal

50% petroleum coke 50% imported coal

SO2 mg/Nm3 37 280 to 300 50 140 to 250NOx mg/Nm3 240 160 to 100 280 200 to 160CO mg/Nm3 13.8 28 73 37Ca/S mol/mol ~3 <2.5 <2.5 2.8

Blend allow to cope with the European regulation: 200 mg/Nm3 for SO2 and NOx

Startups/shutdowns

Démarrages programmés

020406080

100120140160180

1996 1997 1998 1999 2000 2001 2002(aout)

Total

Démarrages chauds

Démarrages tièdes+froidsTotal

Démarrages fortuits

020406080

100120140160180

1996 1997 1998 1999 2000 2001 2002(aout)

Total

Démarrages chaudsDémarrages tièdes+froidsTotal

Since beginning of commercial operation up to December 2003

35556 hours of operation

616 start ups

The unit has been used in peak load between 1999 and 2001

Since 2002 new policy: plant operated in base load

Availability

Disponibilité technique chaudière (hors grève)

76.05

94.34

77.3191.0687.78

94.10

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

100.00

1997 1998 1999 2000 2001 2002

Année

Disp

onib

ilité

Mode de calcul : Energie produiteEnergie demandée

Unavailability Sources

Bilan 1998/2003Indispos

en hproportion

en %Indispos

en hproportion

en %chaudière PSP 2003 62,1 36 8,1

dont éco 268 8,3 6 1,3dont écrans vaporisateurs 999 31,0 28 6,3dont SMT2 709 22,0 0 0,0alimentation charbon 28 0,9 142 31,8allumage gaz 36 1,1 23 5,1air comburant 50 1,5 52 11,6circulation des cendres 889 27,5 109 24,4dont surpresseurs 113 3,5 44 9,8dont liaison foyer-cyclone 119 3,7 0 0,0dont vannes pointeau 144 4,5 46 10,3dont réfractaires 186 5,8 0 0,0dont joints 156 4,8 0 0,0refroidisseur de cendres 35 1,1 6 1,3autres 221 6,9 85 19,0total 3226 100 447 100

indisponibilités totales indisponibilités partielles

Main location of steam leakages

14

3

2

5 6

During operation, steam leakages occured in several locations mainly in the furnace due to default of welding (location 2), stress induced by refractory fixation (location 3), thermal cycling (locations 4, 5 & 6). The external heat exchangers were also subject to steam leakage due to overheating of the tube buddles (location 1).

Troubles on expansion joints

1

2

3

The expansion joints were subject to numerous blockages due to unappropriate design leading to ash plugging.

Agglomerations of circulating ash

1

2 3

The first ash agglomeration occured in 2002 due to combination of minerals by fusion and crystallizationbecause of the aluminates and silicate contents of the “Gard”

coal used to replace the “Gardanne”

coal. The second agglomeration phenomenon followed a period of frequent change of fuel blend and resulted inthe blockage of one of the 4 circulating loops. It seemed that there is a need for a period of stabilisation ofthe bed material composition before changing fuel.

Refractory problems

213

47

5

6

8

The most sensitive locations for refractory damages are the cyclones (locations 4 & 5), the external heat exchangers (locations 1 & 3) and the loop seals (location 6). Other places (2, 7 & 8) are also subject to regular maintenance.

Other sources of unavaibility

1

234

5

6

Some other components encountered some troubles during operation

like : the cone valves (location 1), the ash coolers (location 2), the compressors (location 3), the blowers (location 4), the fluidization nozzles (location 5) and the wind box under the loop seals (location 6).

Questions

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