| Heat recovery steam generator technology
Huge HRSG for Belgium’s latest combined cycle project
“A real juggernaut” says Pascal Fontaine, sales manager at John Cockerill Energy, describing the heat recovery steam generator with integrated SCR (selective catalytic reduction) it is designing and supplying to ENGIE for a new 875 MWe combined cycle power plant to be located at Flémalle near Liège in Belgium
The new combined cycle unit, with an expected commercial operation date of August 2025, will replace the old Awirs power plant complex (originally coal, subsequently employing a range of fuels, including natural gas, oil and biomass). The old plant is in the process of being demolished. The new plant will be a beneficiary of the Belgian capacity remuneration mechanism, introduced in 2021, to help ensure security of electricity supply. The heat recovery steam generator (left) is the biggest and most efficient ever to be supplied by John Cockerill, and one of the world’s largest HRSGs. As well as the dimensions, other challenges associated with project include very
limits (coupled with very tight ammonia slip controls), use of dissimilar welds (necessary to avoid sensitisation of stainless steel), and stringent acoustic requirements, which have a major impact on the HRSG design. The new HRSG is being installed downstream of a Siemens Energy SGT5-9000HL gas turbine (593 MWe), achieving a power plant efficiency of over 63%. The power plant will employ a one-on- one multi-shaft configuration, with steam from the HRSG driving an SST5-5000 steam turbine coupled to an SGen5-1200A generator and the HL gas turbine coupled to an SGen5-3000W generator.
low NOx
A distinguishing feature of the HRSG is its four- module width, with a consequent increase in the number of tubes and heat exchange surface area. The structural steelwork is enlarged to accommodate the four modules side by side. The casing inside-width is 18.7 m and casing height 26 m. This is the first HRSG of this width, and in terms of these dimensions, the largest HRSG ever. HRSGs for class F and H gas turbines typically employ a three-module width. Basic data for the HRSG can be summarised as follows:
Type: horizontal GT exhaust flow, three pressure levels plus reheat (with recovery of heat at the exit of the high pressure ST stage reinjected at the medium pressure level). No duct burner
Live steam operating conditions at HRSG outlet: HP steam at 602°C and 164 bar; reheat steam at 609°C and 40 bar
Boiler dimensions: 73 m long; 25 m wide; and stack height 60 m
Heat exchange surface area: more than 1 000 000 m2 evolution
, which is a milestone in HRSG
Number of tubes: more than 27 000, each 26 m long, also a milestone
Above: Awirs site prior to toppling of partially dismantled chimney (photo: Vincent Questiaux)
Above: Chimney demolition, February 2023 (photo: ENGIE)
Above: Awirs site, April 2023 (photo: Vincent Questiaux)
www.modernpowersystems.com | April 2023 | 21
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47
