THE POWER STATION
Pego Power Station is the most modern coal-fired power station in operation in the Iberian Peninsula.
It features two electricity generating units, each equipped with a steam generator, one turbine-generator unit and a main transformer.
Its main equipment are the boilers, coal mills, turbines, generators and the main control system.
The first unit came into industrial operation in March 1993.
Pego Power Station achieved full commercial operation in October 1995 when the second unit came into commercial operation.
Units 1 and 2 of the power station have identical design, with a unit power rating of 314 MW, each one with its own support infrastructure of cooling tower, feed water system intake and exhaust systems.
The two units share the river water extraction facilities from the riverand the water treatment plant, processing station, coal transportation system, chimney stack and several other general common services.
A very important and significant investment was made in the framework of the LCPD (Large Combustion Plants Directive 2001/80/EC) to minimise the impact of the Pego Power Station emissions to the atmosphere.
Thus, in 2009, the units were retrofitted with a flue gas desulphurisation system (FGD) and a selective catalytic reduction (SCR) – which, in this latter case was the first to be installed in Portugal.
To reduce particulates, the electrostatic precipitators control system was modified by the installation of SIR (switched integrated rectifiers) systems.
LOCATION
PEGO’S ELECTRICITY PRODUCTION CENTER
Estrada Nacional 118, km 142,1
2205-380 Pego
Portugal
The Pego’s Electricity Production Center is located around 150 kilometres NE of Lisbon on the left hand bank of the Tagus river, in the parishes of Pego and Concavada, at about 8 kilometres of the city Abrantes, which is the centre of the municipal and county district.
Access by road is on the EN 118 linking Abrantes and Gavião, via Alvega.
Access by rail is on the Beira Baixa line, through a purpose-built branch line, including a bridge across the River Tagus. This access is fundamentally used to supply coal to the Pego Power Station from the Port of Sines.
THE OPERATION OF THE POWER STATION
Boilers
Manufacturer: Mague/Foster Wheeler EC
Model: natural circulation
Fuel: pulverised coal
Fuel consumption: 108 ton/h
Temperature of intake water: 256 °C
Steam production at MCR (maximum continuous rating): 264 kg/s
Outgoing superheated steam temperature: 535 °C
Outgoing superheated steam pressure: 167 bar
Efficiency: 87.8%
Coal Mills
Manufacturer: Mague/Foster Wheeler EC
Model: MBF 22 (3 grinders)
Number: 4 per boiler
Capacity: 36 ton/h
Coal Burners
Manufacturer: Mague/Foster Wheeler EC
Model: controlled flow/split flame (CF/SF), low Nox burner
Number: 16 per boiler
Electrostatic Precipitators
Manufacturer: Flakt Industri AB, Sweden
Model: FAA 4 x 37,5H + 2 x 93 - 135-A2
Number: 2 per boiler
Gas Flow: 541,6 m3/s
Gas Temperature: 160 ºC
Dust Inlet: 14,935 mg/Nm3
Efficiency: 99,8%
Selective Catalytic Reduction (SCR)
Manufacturer: Alstom
Number of Catalyst: 1 per boiler
Catalyst Type: Honeycomb
Catalyst Volume: 268 m3
Layers per Catalyst: 3
Modules per Layer: 80
Inlet NOx: 800 mg/Nm3
Nox emission at stack: <200 mg/Nm3
SO2 to SO3 conversion rate: 1,1%
Ammonia slip: 1,5 mg/Nm3
Ammonia Consumption: 940 kg/h
Turbines
Manufacturer: Mague/Asea Brown Boveri
Model: D4Y450 (4 cylinders, one shaft, action-reaction)
Nominal speed: 3000 rpm
Steam temperature at cylinder entry point – HP: 530
Steam pressure at cylinder entry point – HP: 162 bar
Steam temperature at cylinder entry point MP: 530°C
Steam pressure at cylinder entry point MP: 43 bar
Alternators
Manufacturer: Mague/Asea Brown Boveri
Model: WTF 22 Im
Rating: 361882 kVA (cos f = 0.85)
Nominal voltage on terminals: 18 kV
Water cooled stator
Direct cooling by liquid hydrogen
Excitation: static excitation system
Main Control System
Manufacturer: Hartmann & Braun Model: Contronic E
Model: Contronic E
Flue Gas Desulphurisation (FGD)
Manufacturer: Alstom
Type: Wet Flue Gas
Number of Absorver: 1 per boiler
Absorber Spray Levels: 3
Inlet Flue gas flow (wet) 1,050,000 Nm3/h (reference case)
Inlet Flue gas temperature 150ºC (reference case)
Inlet SO2 (dry, 6% O2) max 2.168 mg/Nm3 (reference case)
SO2 emission at stack: <200 mg/Nm3
Flue gas discharge temperature at stack inlet: 85ºC
Limestone Consumption: 187 ton/day