Cleaner, cheaper, more effective, secure and independent. Have you ever heard about "Circulating Fluidised Bed" (CFB) technology?
© Fotolia, 2012
Replacing or upgrading old power plants utilising modern technology with high steam parameters and greater efficiency will help preserve resources and reduce harmful emissions. Doing so will also definitely improve public acceptance of coal-fired power plants. However, new plants must also be able to be competitive decades on.
The so-called "Circulating Fluidised Bed" (CFB) technology seems to be the right option. Over the past three decades, CFB technology has evolved from robust small-scale industrial boilers for burning difficult fuels to the successful installation and commercial operation in 2009 of the world's largest CFB boiler of Poland´s Lagisza power plant, rated at 460 Megawatts (MWe). Thus, for the first time in its history CFB technology could challenge traditional pulverised coal technology in large-scale electricity generation applications. Today, more than 80 CFB units rated above 200 MWe are operating worldwide.
Scaled-up CFB plants up to 800 electrical MWe are now available thanks to the research project CFB800 carried out by a consortium of six European partners: Foster Wheeler Energia Oy, Endesa, Siemens, CIRCE and CERTH led by VTT Technical Research Centre of Finland. The CFB800 project required the pooling of complementary knowledge that could not be provided by teams from a single country.
The CFB800 project – successfully implemented from September 2005 until August 2008 - was supported by the European Union (EU): 60 per cent of the total project cost of €3,396,235 was provided by the Research Programme of the Research Fund for Coal and Steel (RFCS), established on 1 February 2003).
CFB technology has already demonstrated several established benefits - such as improved efficiencies, reduced emissions, high fuel flexibility and lower costs - that combine to make this boiler technology a highly competitive option for large-scale utility applications.
CFB steam generators, in contrast to the traditional utility-scale pulverised coal fired steam ones, afford the maximum flexibility in fuel selection and can handle all coal types (even low-quality coals and coal slurries) as well as biomass and peat. The possibility to use a variety of fuel types provides long-term fuel security and full access to arbitrage in the global fuel market.
"You can use different sources. If you can get local fuel at a lower price you are much more secure and independent," says CFB800 project coordinator Antti Tourunen. "That was a key component of our considerations in this project", Tourunen adds. Another significant feature of CFB technology is its ability to tightly control nitrogen oxides and sulphur dioxide emissions - like CO2, greenhouse gases - in the boiler, which can avoid engineering, procurement and construction capital costs.
The initial experience of Poland's Lagisza 460 MWe power plant, which employs supercritical once-through CFB technology has met all expectations, with a 28 per cent reduction in CO2 emissions, as well as NO2 and SO2 reductions.
A very important milestone for CFB technology involves showcasing biomass fuel firing as part of an effort to substantially cut carbon emissions. The 125 MWe CFB boiler at the Kaukaan Voima Oy plant in Kaukas, Finland, is one of the world´s largest CFB installations yet firing 100 per cent biomass. In Poland, the 190 MWe "100%-biomass-based" CFB unit will be installed next to the existing units at the Polaniec power station.