Coal-fired project pushes technology boundaries

London -  A new 858 MW-rated generating unit is being built at the site of Europe’s largest lignite-fired power station in Belchatów, Poland. Upon completion at the end of 2010, it will be one of the country’s most productive and efficient lignite-fired plants with an efficiency rating of around 42%, and one of the world’s most modern installations.

Operator PGE recently awarded Alstom Power a Euro160-million contract for the retrofit of Unit 6 in the Belchatów power plant, Europe’s largest and the world’s second largest fossil power plant with a total installed power output of 4,440 MW. The project is to increase the power output, economic efficiency and safety of the plant.

The project will modernise the infrastructure in Unit 6 to increase its power output and efficiency and extend its lifetime, said Krzysztof Domagala, president of PGE Belchatów Power Plant SA. In addition, he said, emissions of NOx and CO2 from the plant would be significantly reduced.

The retrofit will allow the unit to work within the frame of the new regulations (Directive 2001/80/EC), with a 50% reduction of NOx emissions and a reduction in CO2 emissions by over 400,000 tonnes/year, while ensuring a 20MW increase in the unit's power output and boosting the unit's efficiency to over 41%. Furthermore, the modernisation will improve availability and reliability, as well as extending the unit’s lifetime by 20 years.

The scope of the modernisation covers the reconstruction of the boiler and its auxiliary equipment, replacement of high pressure and intermediate-pressure part of the turbine, increasing power output of the generator and installation of new high-pressure heaters.

"This is the first major integrated retrofit project in Poland and we are very pleased to be able to work on this unique opportunity", said Philippe Joubert, President of Alstom Power. "This project will benefit from Alstom’s expert knowledge of turbine and boiler technology, our proven track record in integrated retrofit projects, as well as our position as leaders in clean power production."

In 1997-2004, Alstom carried out contracts regarding the modernisation of the low pressure parts in 12 turbines at Belchatów, a first step in the upgrading of power capacity. Since then, PGE has continued its strategy of modernising units 3-12 in order to meet emission requirements imposed by the EU directives and in order to extend the lifetime of the units. Alstom was awarded a contract to provide a turnkey, 858 MW new supercritical unit to the plant.

Last December, PGE and Alstom signed a memorandum of understanding for the development and implementation of carbon capture and storage technology at Unit 12 of the Belchatów Power Plant 9. This pioneering project involves an amine-based scrubbing technology being developed in collaboration with the Dow Chemical Co. 

At present, Alstom is executing retrofit projects of HP and IP parts in steam turbines operated at Units 4 and 5 - to be finalised in 2009 and 2010-11, respectively.

Two innovative flue gas coolers, equipped with heat exchangers using the AlWaFlon pressure hose system based on DuPont Teflon PTFE, will contribute to the plant’s comparatively low fuel consumption, reduced emissions and high sustainability. The flue gas coolers are developed and supplied by the engineering company Wallstein of Recklinghausen, Germany.

The two units, scheduled for delivery in the first half of 2009, are each equipped with five heat exchanger modules in which a total of approximately 500,000 meters of AlWaFlon® pressure hoses are integrated. After commissioning, they will reduce the temperature of the flue gas by about 50K and, in doing so, generate two times 32 MW of heat energy.

The design will contribute towards the feed water heating at the power plant, while the surplus steam will be used for energy production, thereby improving the overall energy balance of the plant.

AlWaFlon is defined by the interaction of an almost entirely chemically-inert fluoropolymer, designed for use in highly corrosive and reactive gases, and the use of complementary processing methods. Joint developers are Wallstein, DuPont, the manufacturer of the base fluoropolymer material, and Fluortubing of Utrecht, The Netherlands,  the supplier of installation-ready, pre-formed pressure hoses.

 "We chose AlWaFlon because – in contrast to the previously all-prevailing nickel-based alloys – it even resists highly corrosive mixed acids of SO2, SO3, HF and HCl, which condense on the hose surface during cooling of the flue gases," said Peter Dittmann, technical manager at Wallstein.

"The AlWaFlon concept combines cost-efficient processing and application benefits with exceptional consistency in terms of its properties over long production periods, from charge to charge and for the entire hose length," added Alex Soeterbroek, managing director of Fluortubing. "Compared to many other fluoropolymer grades, the application attributes of AlWaflon include higher upper service temperatures of up to 260 °C, a significant increase in the Vicat softening temperature to between 130 °C and 140 °C, as well as high flexural fatigue strength and stress cracking resistance."

Back in 2007, Emerson received a $27 million contract to modernise the instrumentation, control and electrical subsystems of generating units 3 and 4 of the Belchatow Power Plant. The vendor's Ovation system was selected to monitor and control each unit's Sulzer-type boiler and balance of plant processes and equipment, as well as the 6kV and 0.4kV electrical switchgears and unit power output. The Ovation system was also interfaced to each unit's BBC-type turbine controls.