PRESSURIZED FLUIDIZED BED COMBINED CYCLE DEMONSTRATION PLANT (79 5 MWE) [STAGE 4]

Ziel

Design, construction of a PFBC plant with a net power of 79.5 MWe based on the ABB Carbon technology. The aim is to transfer to Spain a high technology and to give the possibility to a spanish boiler maker to demonstrate it. It will be possible to exploit and use the abounding reserves of subbituminous coals from Spain.
The fluidized bed is located in a pressurized vessel (12 bar), 14 m. in diameter and 22 m. in height. The bed height is 4 m. and the fluidization velocity is 0.9 m/s. Gas turbine specially designed by ABB Carbon for its PFBC 200 scheme (GT35).
Problems of several types might be observed regarding the jams in the various solid matter travelling paths :

- Transport lines without redundant equipment, particularly regarding fuel preparation and feeding. For instance, bucket elevators under preparation or bed feeding compressor.
- In fuel injection. Inadequate or non tested fuel preparation. Erroneous coal and lime size distribution. Humidity excess.
- Operating manoeuvres. For instance, load lifting at a slow rate that did not properly take advantage of pressure differences between the burner and the final point of the cyclone ash removal system.
- Aggregate formation in cyclones, which later moved on to the ash removal lines.
- Non optimal design of solid matter removal components. Particularly in the cyclone discharge lines.

Currently only persists, in a significant manner, the problem of jamming in the cyclone discharge lines, which is nowadays the main cause of stoppages, although it is also known that this phenomenon may be controlled or even avoided by maintaining the plant without exceeding certain operating parameters.

The formation of sinters in the cyclones may give rise to the release of scales that jam the ash removal path. Different modifications have been implemented, so that the problem is a minor item, although it is not finally solved.

Year Hours of production Average Maximum Gross
Power (MW) Power Prod.(GWh)
1991 1.382 49,3 75,2 68,14
1992 3.169 56,8 75,7 179,85
1993 5.130 63,1 77,7 323,81
1994 4.800 64,7 74,8 310,572
1995 5.626 67,2 78 372,216

ENVIRONMENTAL RESULTS : From the beginning of plant operation it was observed that indeed the expected goals regarding good sulphur retention rates and low levels of nitrogen oxide emissions were going to be met. Now we know that we may operate the plant continuously with sulphur retention rates higher than 90% and nitrogen oxide emissions lower than 350 mg/Nm3.
The project consists of installing a pressurized fluidized bed combustion (PFBC) system, which is coupled to the steam cycle of an existing thermal plant, where the present pulverized coal boiler is put out of service.
The PFBC system which is coupled for the electric generation is made up of the following basic components :
- Preparation and feeding of fuel and sorbent.
- Pressure vessel, having the following elements : actual boiler, gas cleaning cyclones, ash coolers and load regulation tanks.
- Combustion gases expansion turbine which works the compressor which supplies fluidification and combustion air to the boiler.
An alternator coupled to this turbine generates electricity.
Steam system consisting of steam turbine, heaters and feed water pumps. The turbine is coupled to an alternator where most of the unit's electric power is produced.
- Auxiliary systems, water treatment, cooling circuit, ash evacuation, electric switchyard.
The present thermal power plant of Escatron islocated in the vecinity of the mining basins of Teruel-Mequinenza and on the banks of the Ebro River. It had four units, 2 x 25 MWe and 2 x 62.5 MWe, only one of the latter of which was running.
The project replaced the old PC boiler of the fourth unit with a PFBC system, recovering the steam system and all the auxiliary services of the plant, modifying them when necessary to adapt them to the new facility.

Programm/Programme

ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989

Thema/Themen

8.3 - COMBUSTION INTEGRATED TO THE END-USE CYCLE

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

EMPRESA NACIONAL DE ELECTRICIDAD (ENDESA)

EU-Beitrag

Keine Daten

Adresse

PRINCIPE DE VERGARA 187
28002 Madrid
Spanien

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