SCALING UP ONCE-THROUGH SUPER-CRITICALCFB BOILERS TO 800 Mwe

摘要

Circulating fluidized bed (CFB) combustion has established its position as a utility-scalernboiler technology. Plant sizes up to 300 Mwe are in operation today, and designs for largerrnboilers are being developed. The first CFB boiler employing supercritical steam parameters isrnbeing designed by Foster Wheeler for delivery to a Polish utility, Po ? udniowy KoncernrnEnergetyczny SA (PKE), for their ? agisza power plant. The plant will have an output of 460rnMwe.rnDeveloping CFB technology to even larger sizes and higher plant efficiencies is an ongoingrnchallenge. There is an increasing demand for boilers in the size range of 600 to 800 Mwe, asrnexisting power plants are aging and new replacement capacity has to be built. CFB technologyrnis now emerging as an alternative plant of this size, thanks to the benefits it offers in terms ofrnfuel flexibility and inherently low emissions. New, modern power plants need to have highrnefficiency for economic reasons and to minimize emissions, including CO2. Plant netrnefficiency of approximately 45% (LHV) is expected. This calls for utilizing ultra supercriticalrnsteam parameters, together with an optimized power plant cycle and high boiler efficiency.rnFoster Wheeler and Endesa, together with a group of other interested companies fromrnGermany, Greece, Finland and Spain have initiated a study for an 800 Mwe power plantrnbased around CFB technology. The group is working on a conceptual boiler design to betterrnunderstand the feasibility of a large CFB design. Imported bituminous coal has been used asrnthe base fuel in the study. The plant is designed for ultra-supercritical steam parameters, withrna steam pressure of 300 bar, a superheated steam temperature of 600 ℃, and a reheat steamrntemperature of 620 ℃ to maximize plant efficiency.rnPreliminary studies show that the scale-up of critical CFB components, such as the furnace,rnsolids separators, and fluidized bed heat exchangers to 800 Mwe is possible with the selectedrnfuel. The actual scale-up of the dimensions and size of plant components required is quiternmoderate, due to the modular approach adopted for the boiler design. A more detailed studyrnof a 800 Mwe CFB power plant covering an optimized steam cycle, boiler design, emissionrnperformance, dynamic behavior, and economical feasibility will be carried out in a three-yearrnresearch program partly funded by the Research Fund for Coal and Steel (RFCS).