Abstracts - VGB PowerTech Journal 11/2013

Operational flexibility of modern “heavy duty” gas turbines with sequential combustion

Peter Marx, Martin Liebau and Belén Gasser-Pagani

Current and future gas turbines are required to provide a wide range of operational flexibility with maximised availability and reliability at lowest emissions. Alstom’s KA26/GT26 combined cycle power plant technology with its sequential combustion is particularly suited to meet such flexibility requirements. Field experience, in particular from the GT26 Upgrade 2006 with 50 units in commercial operation, demonstrates this operational flexibility and is reflected by a high commercial service factor of more than 70 %.

J920 FleXtra gas engine combines CHP and flexibility

Klaus Payrhuber

The paper will discuss the benefits of GE’s Jenbacher J920 FleXtra larger gas engines in combination with CHP, as operating flexibility is becoming more important with the growing number of renewable installations. Combining cogeneration with high total fuel efficiency and operating flexibility can be greatly achieved with gas engines in combination with heat storage. Such flexible power plant with the 9.5 MW J920 FleXtra installed in multiple units configuration can be as big as 100 or 200 MW.

Modernisation of existing gas turbine power plants with load flexible gas turbines of the LM series

Harald Gretscher and Claus Colling

Modernisation or “repowering” of outdated gas turbine plants is in the focus of interest as the power plant fleet is aging. An elegant solution is to simply replace outdated gas turbines with a modern, load flexible aero derivative gas turbine. Customers are interested to maintain as much as possible of the existing power plant infrastructure. On the basis of executed references, the typical challenges in repowering projects are explained.

Gas turbine performance and maintenance continuous improvement

Vladimir Navrotsky

OEM of gas turbines are continuously focused on their product development and improvement in order to meet the dynamic market changes and to improve power plant competitiveness and profitability. Continued enhancement of existing OEM products and services is an important part of the OEM’s integrated development concept. In this paper the application of Siemens’ product & ser vices improvement concept is demonstrated on the example of the SGT-600 gas turbine.

Influence of operation and regeneration caused variances of turbine blades

Sebastian Hohenstein, Jens Aschenbruck and Jörg Seume

Turbine blades are one of the main cost factors when maintaining gas turbines, because the blades must be refurbished or replaced regularly due to high thermal and mechanic loads. As a consequence, geometric deviations from new parts occur on these blades. These deviations have a significant influence on the aerodynamic losses and therefore on the efficiency of the gas turbine. The aim of this research project is to investigate the influence of geometrical deviations at macro and micro scale of high-pressure turbine blades on loss and efficiency.

Functional safety: Application on gas turbine protection

Andreas Belzner, Wilfried Blotenberg and Gerd Weber

Functional safety is defined in a number of international standards. Protection systems shall be designed such that they are able to avoid unacceptable dangerous situations for persons or environment. The protection system has to be designed according to so-called SIL (safety integrity level) levels. These correspond to the risk associated with the damage. The application of the principles of functional safety was examined within a VDMA working group considering all aspects of gas turbine safety. The article explains the risk analysis and shows some examples of such analyses.

Back to basis – Visual inspection for gas turbines

Joel Udoh, Andrew Jenkins and Salim Laher

The power generation industry faces unprecedented change and challenges across the entire supply chain. Plant inspection is a critical component of this process. There exists a wide range of inspection methods available. However, the role of visual assessment amongst the array of inspection techniques available should not be underestimated. Visual assessment forms an integral part of the component life cycle. Information gleaned from inspection windows during the life cycle of the plant can be used to build an accurate history of the component and its degradation under given running regimes. This information can validate reliability engineering models helping to develop a robust database of knowledge across a fleet of components thus enabling the integrity of critical components to be accurately assessed.

Eliminating hazards to personnel – Alternative fire-extinguishing systems for Siemens gas turbines

Wolfgang Hensel

CO2 has long been the established fire-extinguishing agent for gas turbine enclosures owing to its excellent fire-extinguishing properties. Yet, as a fire-extinguishing agent, CO2 can also proof highly hazardous or even deadly to personnel. Two alternatives are offered: the nitrogen-water extinguishing system “Sinorix H2O Gas” and the high-pressure fine-spray system “ProCon XP”. The article describes the mode of operation of both these alternative solutions and their conceptual designs for a large gas turbine enclosure.

Knowledge management in the area of operations, technology and maintenance

Walter Hahn and Jochen Pracharz

Rapid access to and efficient utilisation of company internal knowledge is an import factor for the success of generation technology and maintenance in companies. In search for a better use of information, experts often mention the issue of “knowledge management”. But what lies behind the terminology “knowledge management”, especially in the area of operations, technology and maintenance? It is shown how technical areas are able to “make knowledge useable”, “prevent unlearning” and “empower employees” by the three instruments peer reviews, document management and learning opportunities.

New methods for NOx emission reduction in fluidised bed combustion: CFD modelling results from a BFB boiler

Perttu Jukola, Marko Huttunen, Pauli Dernjatin and Jouko Heikkilä

Fortum and VTT have developed new air staging methods to reduce primary NOx emission from stationary fluidised bed combustion (SFB). These methods are based on the appropriate choice of secondary (and tertiary) air vertical position depending on the mode of operation and on the optimisation of low furnace air distribution, which can be controlled by additional air feed into the near bed region. Computational fluid dynamics (CFD) equipped with specific models for SFB combustion was systemically applied to investigate alternative options for air system design and air distribution in a SFB furnace firing a fuel mixture of forest-based biomass and peat. Based on the results of CFD, optimum concepts can be realised.

The lignite industry and regional development: Interactions exemplified by the Rhenish mining area

Lars Kulik and Jens Voigt

Even in times of globalised markets, the German lignite industry retains its local and regional roots. Viewed against this background, the relationship between lignite industry and regional actors, and the interactions between the two play a major role in the perspectives for this branch of Germany’s energy sector. Today, the links between the lignite industry and regional bodies are those of a partnership at eye-level. This type of relationship between the industry and regional actors has led to new forms and methods of cooperation at various levels. This is particularly evident in the efforts to re-shape the regional structure, develop the structure of townships and strengthen the economic structure with lignite playing an important role and new partners which are gaining in importance.

Challenges to lignite mining in Lusatia: From presence towards future

Roswitha Partusch and Wolfgang Ketzmer

Lusatian lignite is facing even more challenges due to the turnaround in energy policy; meeting these challenges is of decisive importance for the future of the domestic energy source. Parallel to the continuous development of the mining region, the increasingly growing embedding of lignite into the interests of the social, economic, and ecological environment of the region is gaining in importance. This development is duly considered by assuming responsibility for the social environment and in the debate about ongoing long-term lignite mining planning procedures by making objective contributions and underlining clear commitment to domestic lignite and its important role for the economic development.