Abstracts - VGB PowerTech Journal 7/2008

Future Developments for CO2-free Power Plant Technologie with Integrated Gas Turbines

Dieter Bohn

The reduction of CO2 emissions is the pre-eminent goal of most current developments in modern fossil-based power plant engineering. A disadvantage is the reduction in efficiency inevitably caused by the reduction techniques. This does not only reduce the economical viability of the power plant but also the life-span of the natural resources at the basis of the processes. In order to mitigate these side-effects, a considerable increase in power plant efficiency has to be achieved. In the short-term research efforts will concentrate on the improvement of existing technologies. The mid-term development will focus on new technologies, especially with regard to materials and cooling techniques.

Development of a Low-emission Hybrid Burner for Combustion Chambers of Gas Turbines

Stanislav Vesely, Jevgenij Vinogradov and Jurij Zacharov

Retrofitting of existing gas turbines in order to reduce emissions is differing from the development of new combustion chambers for new gas turbines. The emission limits of NOX and CO2 to be expected after 2015 cannot be achieved with diffusion combustion, but pre-combustion is required to safely meet emission targets. Pre-combustion is a combination of a lean mixture (low output) with diffusion combustion. A hybrid burner was developed and tested at a special test rig at atmospheric conditions and elevated pressure.

Thermodynamically-based Definition of Limits for Nitrogen Oxide Emissions of Gas Turbines

Manfred Freimark, Uwe Gampe and Mario Raddatz

The policy of the Federal Government for an integrated energy and climate programme represents the basis for the Regulation to the Federal Emission Control Act (37th BImSchV) which comprises revision of emission limits with consequences for gas turbines. The necessary connection is shown between gas turbine efficiency and nitrogen oxide emission limits on the basis of thermo-dynamical considerations. Thus, a conflict of targets between climate protection and air pollution prevention and a discrimination of high-efficient gas turbines can be avoided. The “eta algorithm” is a proper approach which does not privilege these plants at all.

Ceramic High-temperature Heat Exchanger  for Application in High-temperature Processes

Jan Schulte-Fischedick and Stefan Zunft

High-temperature heat exchanger based on ceramic materials can be applied beyond the operating range of metallic high-temperature alloys and thus represent a key component for increasing the efficiency of industrial processes. Its design and realisation are, however, afflicted with several challenges. The prototypic realisations of singles plates and a complete heat exchanger core indicate the feasibility of the production process.

New Possibilities for the Application of Ceramic Heat Exchangers in Processes with High Temperatures and Difficult Atmospheres

Andreas Hiller, Jan Löser, Christoph Schmid and Gotthard Nauditt

Ceramic was introduced as a material within many sectors of the economy. However, some problems still have to be settled. Solutions seem to be possible through the development of modular heat exchangers to discharge high-temperature heat from corrosive atmospheres in different applications.

Carbon Capture Technologies for the European Market

Daniel Hofmann, Tobias Jockenhövel and Georg Rosenbauer

The article summarizes developments in pre- and post-combustion carbon capture technologies. Both techniques are presented. Besides, the paper will additionally provide an insight into what capture-ready design for fossil-fuelled power plants could entail from a technical perspective since "capture ready" is a prerequisite for the licensing of new coal-fired power plants in the EU. The current focus is on coal-based plants due to the lower capture costs. However, gas-based power generation is equally accessible.

The Long Road towards the Sea - Offshore Wind Farms, Status Quo and Prospects

Martin Skiba

There is great potential for producing electricity at sea and the turbine technology is available. Major obstacles have now been resolved. The "Alpha Ventus" offshore test wind farm is to be taken into operation in the North Sea this year. Continued expansion will mainly depend on whether it is possible to cope cost-effectively with the considerable differences between onshore and offshore wind energy usage, particularly in relation to operation.

State and Recent Advances in Research and Design of Solar Chimney Power Plant Technology

Theodor W. von Backström, Reinhard Harte, Rüdiger Höffer, Wilfried B. Krätzig, Detlev G. Kröger, Hans-Jürgen Niemann and Gideon P.A.G. van Zijl

In solar chimney power plants the air under the glass-covered collector is heated by solar radiation, and then released via a central chimney into great atmospheric heights. This mass-stream of warm air drives turbo-generators in the chimney foot producing electricity. The article describes recent progresses in research and development of this technology applicable primarily in arid zones.

The Present Shortage Situation on the Maintenance Service Market - A Hopeless Situation?

Frank Benzel and Herbert Hopstein

The market for new power plants is presently being dominated by dramatic price rises and fully booked manufacturing capacities over the next few years. This situation also causes severe problems in the procurement of maintenance services and spares. In many cases the suppliers of new power plants and maintenance services are identical and access the same human and production resources. The paper provides an insight into the measures taken by RWE Power to assure a reliable procurement of services.

Deformation of Furnace Roof of Sub-critical One-through Boiler

Behzad Boroumandi

Gas tight membrane tube panel of furnace walls and roof of boilers are flexible therefore certain deformation is tolerable. Factors such as expansion restraint and temperature difference between adjacent tubs are responsible for deformation. Typical examples of observed damage are shown, potential causes of abnormal temperature differences are discussed and results of extensive investigations are presented.

Strengthening of 40 Years Old Coal Bunkers with Carbon Fibre Fabrics

Alfons Frey, Jürgen Krams and Andreas Kleist

Within the scope of inspection works at a power station of the Grosskraftwerk Mannheim AG lots of corrosive damage was found on the reinforcement of 40 years old coal bunkers. The bunker was refurbished with polymer-modified mortar (PCC) that is able to carry abrasion-resistant tiles for the mechanical protection of the bunker walls and for the static strengthening of the coal fibre sheets at the outside of the bunker.

New Quality Criteria for Gas-in-oil Analysis

Eckhard Bräsel and Ute Sasum

An innovative way to overcome the difficulties with the DGA accuracy is the definition of a Natural Internal Standard (NIS) for transformer oil under saturation condition in an air-breathing transformer. This represents a further development of the external air-in-oil standard defined by IEC 60567. On-line equilibrium gas, for which pressure and nitrogen concentration must be measured accurately, aims at providing direct evidence of this state.

Optimisation of the Gas-in-oil-testing Method for Transformers by Means of Automation

Herbert Prenzel, Elke Grzenia, Ivanka Atanasova-Höhlein and Ralf-Ulrich Seifer

The implementation of the automated degasification of transformer oils is based on the fact that the state of the sampling material extracted from a transformer is quasi-stationary. In other words, there are no stationary states or balances. Therefore, sample preparation and tests must be adapted to these marginal conditions. In our opinion, this has, on one hand, been achieved thanks to the development of an automated sample preparation method ensuring reliable and precise results from this combined degasification and testing process. On the other hand, these tests comply with the applicable IEC- standards. The standards were developed as a basis for state assessments of transformers and transformer fleet maintenance strategies.

Development of Amine Containing Scrubber Solutions for Separation of CO2 from Flue Gases

Kevin Brechtel, Harald Thorwarth, Sven Unterberger and Günther Scheffknecht

One well-known process for CO2 capture in power plants is the use of an amine scrubber system, normally used in the chemical industry. The application of this amine process in power plants leads to a power plant efficiency reduction of about 14%-points, caused by the thermal regeneration of the amine solution. In order to reduce the efficiency decrease, new solvents are investigated and developed. These investigations, carried out at the IVD, have shown that the molecule structure of the amines has a significant influence of the solvent behaviour during CO2 capture. The results of the experiments performed now offer the possibility for a focused development of new solvents.