Heat recovery steam generator technology |
Left: Acoustic enclosure
Above: Visualisation of new plant Right: CFD modelling
Weight: 10 500 t
Tube materials: hottest superheater and reheater tubes will employ austenitic stainless steel finned tubes in SA 213 Super 304, with Incoloy transitions to ferritic alloy steel outlet headers in SA 335 P92, which is also used for the main steam piping to the steam turbine Integrated SCR achieving reduced NOx
NOx ; max NH3 slip 1.5
currently noting a market shift towards OTB technology to accommodate the largest gas turbines. A vertical-flow OTB,
with low
residual ammonia. Requirements (at the stack): less than 10 mg/Nm3 mg/Nm3
Acoustic enclosure: self supported acoustic walls, with noise traps. Sound pressure level close to the boiler has to be less than 45 dB(A), facilitated by long HRSG inlet transition duct. Gas turbine sound power level is 165 dB(A) CFD modelling performed for the SGT5- 9000HL has demonstrated that there is no need for an attenuation flow grid in the HRSG inlet duct thanks to the long transition duct between GT exhaust and HRSG inlet. This long straight duct is just a provision for the potential future addition of a bypass stack Despite the high HP pressure, the HRSG is of the conventional drum type, and is perhaps at the limit for this technology, because of water/ steam separation limitation in drum demisters. To achieve higher pressures, a once through boiler (OTB) configuration would be preferable for the HP circuit, and indeed John Cockerill is
manufactured by Siemens/NEM, is employed at the Keadby 2 HL lead CCGT project in the UK. Boiler Stress Evaluator software (based on Euro Norm codes), developed by John Cockerill, will be uploaded into the Flémalle power plant DCS and combined with dedicated temperature measurements on critical components such as the outlet headers and HP drum. This will enable boiler lifetime to be monitored and support predictive maintenance. Thermocouples will provide temperature profiles over the thick walls during transients, and induced thermal stresses will be calculated. The order for the Flémalle HRSG was placed at the end of 2022 and site erection work is expected to start at the end of 2023. The new combined cycle plant will be highly flexible in operation. “Designed to facilitate frequent start-ups and changes of regime, it will also provide all the flexibility necessary to adapt to the significant production fluctuations required by the intermittent side of renewable energies”, says Eric Absil, president of John Cockerill Energy Solutions, noting that in the current context of the
Flue gas fan Flue gas fan Flue gas inlet Vaporiser
energy transition, combined cycle power plants are “a key element of national energy mixes.” Gilian Deblauwe, managing director, ENGIE Thermal Cluster North Europe, says his company has “made great efforts to develop a state-of-the-art project in Flémalle in order to reduce the impact on the environment and to integrate the plant into local communities”, and “decided to go beyond its obligations by further reducing NOx
emissions…
We are convinced that the Flémalle plant, which represents an investment of 500 million euros, will be one of the world’s best benchmarks in terms of efficiency and emissions control.”
ENGIE subsidiary Electrabel is acting as EPCM contractor for the Flémalle combined cycle plant and has thus contracted with John Cockerill for the HRSG package, which includes balance of plant portion and pipe rack to steam turbine building, and also HRSG erection activity. John Cockerill has previously worked with ENGIE on the supply of heat recovery steam generators for combined cycle power plants, at Amercoeur (Hainaut, Belgium) and Dunamenti (Hungary).
Flue gas outlet
Ammonia flow control unit (AFCU)
Vapourisation of aqueous ammonia
OH) using hot flue gas to produce NH3 for the selective catalytic reduction system
(NH4 22 | April 2023|
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