PT 03

The Success of Lignite-fired Power Plants in Lusatia

Heinrich Breuer

Power generation based on lignite has been a long success story in the Lusatia area. At the beginning of the 20th century it was the availability of primary energy that pushed the Lusatia area into the focus of industry and so lignite-based power generation was promoted. Present state of the art shows how much experience has been gained over the past 100 years. Power output has been increased continuously and has reached a dimension that nowadays it can be operated at a technically and economically reasonable level; associated problems could be solved.

KOMET 650 – Coal-fired Power Stations with Steam Temperatures up to 650 °C

Helmut Meyer, Dieter Erdmann, Peter Moser, Sabine Polenz

In the only testing facility of its kind in Europe, materials for coal-fired steam turbine power stations were tested at temperatures up to 650 °C under the project title “KOMET 650”. In this 10-year-plus field test, the materials were stressed to their limits and exposed to realistic power station conditions. The findings and data obtained can be used in the construction of the new generation of power stations with temperatures over 600 °C and for the 600 °C plants already in operation. Even in power stations with the highest process parameters (700 °C/350 bar), a number of components work in the temperature range investigated, enabling the findings to be used here also.

(Printed in German. English paper available .)

KOMET 650 – Investigations of the Operational Behaviour of Boiler Materials and their Welded Joints at Temperatures up to 650 °C

Ralf Uerlings, Udo Bruch†, Helmut Meyer

This study describes the results obtained from the superheater materials tested under operational conditions within the KOMET 650 joint research project. To assess steam-side oxidation behaviour and structural properties, a total of ten identical test sections composed of the material groups martensitic steels, austenitic steels, nickel-based alloys and welded joints were installed in the Westfalen power plant, Unit B, and subjected to metallographic examination after 5890, 12000, 17700 and 23215 full-load hours. Based on the findings from these investigations, the study derives the practical limits of the materials tested, with the aim of obtaining meaningful basic information for the planning and construction of future components for state-of-the-art power plants.

(Printed in German. English paper available .)

KOMET 650 – Findings on the Operational Behaviour of the Pipe Materials Used, and Assessment of the Overall Design in the Light of the Current Regulations

Peter Körner, Gereon Lüdenbach, Helmut Meyer, Konrad Peters, Ulrich Reiners

Within the ”Large diameter pipe test bed” sub-project of the KOMET 650 research project, the behaviour of pipework components in various materials (P 92, E 911, AC 66, 1.4910 and IN 617) and their welded joints was investigated with respect to their relaxation and creep behaviour. Fitting the pipe with load, displacement and expansion sensors enabled to reconstruct the stress redistributions caused by the relaxation processes that took place. Investigations were also carried out during operation on the joints in the highly-stressed areas of the elbows and welds using the foil impression method, and after removing the pipe, by studying metallographic sections. The damage found (density of creep pores) was set against the level of stress on the various components.

(Printed in German. English paper available .)

KOMET 650 – Investigation of Materials for Use in Steam Turbines at Temperatures up to 650 °C

Reinhard Knödler, Stefan Straub, Brendon Scarlin

The report covers the results of exposing materials for steam turbines to increased steam temperatures in two modules of the KOMET 650 testing facility at the Westfalen power plant. Ferritic/martensitic steels with 9 to 12 % Cr and austenite and nickel-based alloys were investigated. Some experimental coatings on low-alloy Cr steel were also tested. The principal findings are presented. It will become possible to construct advanced power stations to be operated at higher temperatures.

(Printed in German. English paper available .)

KOMET 650 – Operational Experience with Control Valves in the High Temperature Range

Olaf Tebbenhoff, Dierk von Nordheim, Jochen Saß, Ingo Balkowsi

Welland & Tuxhorn AG, one of the leading manufacturers of industrial valves for the power station industry, was responsible for control valves within the KOMET 650 research project. Extensive experimental and mathematical investigations have been carried out on control valves to improve long-term resilience and operating safety. In the design of such highly-stressed valves not only the choice of materials but also suitable structural variations need to be considered in order to provide reliable and fail-safe valves in the longer term.

(Printed in German. English paper available .)

Torrevaldaliga Nord Power Plant: One of the Cleanest and Most Efficient Coal-fired Power Stations Worldwide

Leonardo Arrighi, Sauro Pasini, Antonio Dentini, Gian Maria Guardiani, Matteo Toschi

In the light of market liberalisation Enel decided to switch the Torrevaldaliga Nord Power Plant from oil to coal firing. The new plant comprises three coal-fired units with a total capacity of about 1980 MW. Also in international comparison the project is among the most ambitious and advanced projects of its kind, both in terms of its technical and environmental characteristics. Construction activity started in March 2004 and the first unit will be in commercial operation at the end of 2008.

Tray Absorper Technology for New FGD Plants and Retrofits

Gerald Heinze, Helmut Welp

The paper presents the FGD systems of the new power plant installations of Vattenfall Europe Generation AG & Co. KG at Boxberg Unit R, Hamburg–Moorburg Units A & B as well as for the Oxyfuel pilot plant at Schwarze Pumpe power plant. The distinctions of the Babcock & Wilcox Absorber System compared with the conventional, single loop FGD open spray tower design are illustrated.

Improvement of SO2 Removal with Application of Wall Rings and Advanced CFD Modelling – The Case of FGD Unit Megalopolis

Johann Hofelsauer, Winfried Notter, Lucca Marocco, Maria Agalioti, Paul Leoussis

Megalopolis SES is a lignite-fired steam-electric power plant (total 850 MW) located in southern Greece. The plant consists of four units. Unit III will be retrofitted with WFGD unit in order to meet the emission values of LCP 2001/80/EC. A CFD modelling of the absorber has been used to define gas, liquid and SO2 distribution inside the absorber with the goal to combine the optimised SO2 removal with lowest possible power consumption. The paper shows the results of the CFD study on Megalopolis III WFGD containing the fluid dynamic optimisation of nozzle arrangement including wall ring location.

NOx Reduction by Flameless Combustion of Pulverised Coal

Hannes Stadler, S. Tschunko, Malte E.C. Förster, Reinhold Kneer, Christian Fielenbach

A significant reduction of primary NOx emissions was achieved by developing a novel burner design. With a combination of internal flue gas recirculation and moderate air staging, NOx emissions could be reduced to below 200 mg/m3N for lignite as well as hard coal.

Enhanced Fine Particle and Mercury Emission Control Using the Indigo Agglomerator

Rod Truce

Fine particles put health at risk. The Indigo Agglomerator enhances fine particle collection by attaching the fine particles to the larger particles. These large agglomerated particles are easily collected in existing control devices, such as electrostatic precipitator, fabric filters, scrubbers and cyclones. Recent regulations in the USA require mercury emission control on coal-fired power stations. These emissions are also more easily reduced by the agglomerator.

Carbon Capture and Storage Power Plants – Effects of ASU Integration on IGCC Performance and Gas Turbine Operation

Mathias Rieger, Robert Pardemann, Hardy Rauchfuß, Bernd Meyer

Carbon Capture and Storage (CCS) power plants offer a promising alternative for a considerable reduction of green house gas emissions. The paper exemplifies the modelling and the simulation of an IGCC power plant with CO2 capture, whereas special focus is laid on the effects that occur by integrating the air separation unit (ASU) within the gas turbine process. The simulation results are presented in terms of technology and their influence on the overall power plant efficiency.

Safety Philosophy for Hydrogen-cooled Generators and their Related Systems

Klaus Langenbacher, Gerd Mundinger, Severin Wälchli

This publication describes the safety philosophy of Alstom regarding the hazardous area classification and the determination of the extension of the hazardous area around hydrogen-cooled generators and the related auxiliary units. Basis for the determination of the hazardous area extension are the extensive tests carried out.