Abstracts - VGB PowerTech Journal 12/2015
Editorial: Shape the future of our energy supply
DI Wolfgang Anzengruber
We are living in a time of constant change. Politically, economically, technologically. Ever more often the focus of change is placed on energy policy: The sources from which we draw our electricity, how reliable and calculable the supply is and how resilient our grid infrastructure is determines the desirability of business locations and a society’s prosperity.[more...]
The FlameSheet™ combustor system: A retrofitable, step change improvement in the flexibility of existing E & F-class gas turbines
Peter Stuttaford, Hany Rizkalla, Khalid Oumejjoud, Jeff Benoit and Waldemar Schneider
The patented FlameSheet™ combustion system employs a simple, two-stage radially-inflow “combustor-within-a-combustor” concept. The result is an improvement of up to 30 % increase in the operating window of operation with single digit NOx and CO. This means for a gas turbine that previously could only turndown from base to 60 % load, that now, with the FlameSheet™ the GT could operate down to 30 % GT load. This very flexible combustion system, designed to operate up to 32k fired hours between inspections, has proved to be ideal for LNG or alternative fuel operation such as hydrogen with up to a 3x increase in modified Wobbe Index (MWI) operational range.
Realisation of the quick start ability in Stadtwerke München’s combined cycle CHP power plant “HKW Süd” – Concepts and operational experience
Julius Becker, Jürgen Gerhard and Julian Niedermeier
For the marketing of positive tertiary control energy (minute reserve) the start-up process was accelerated in two units at the HKW Süd plant. There is no bypass on the flue gas side. Thanks to the implementation of quick start ability, the system can be used for marketing positive tertiary control energy from the turn operation with the boiler kept warm. The system was originally built as base-load plant. The various changes to the system in terms of process control and procedure technology will be presented. In addition to the extensive process control changes, mention will also be made of the heat maintenance of the idle unit with regard to pressure and temperature as well as the switchover from pre-ventilation to post-ventilation for the heat recovery boiler in the gas turbine control.
Innovative cooling and combustion systems for industrial gas turbines of highest efficiency
Karsten Kusterer, Ryozo Tanaka and Dieter Bohn
In order to address the diversity of market demands, an industrial gas turbine system of highest efficiency in its class and enhanced operational flexibility has been developed. The key factor in the design process was the application of advanced cooling technologies based on modern computational simulation and analyses systems. The complex cooling task is explained for the first vane nozzle of the gas turbine showing simulation results as well as measurement results from the test engine. Enhanced fuel flexibility has been achieved by application of a supplemental burner concept to the gas turbine combustion system. It allows the combustion of fuel gas with high hydrogen content and still safely meets the emission limit values.
Advanced gas turbine validation results
Marcus Scholz and Rudolf Lachner
Over a period of six months, from October 2014 to March 2015, the first 9HA gas turbine was validated at General Electric’s unique full speed, full load facility in Greenville, USA. The tests explored the true operating capability on this first “HA” technology platform beyond real-world conditions – and far beyond what could have been tested in the field. Since the testing facility is using an aeromechanical load compressor of the same size as the gas turbine itself, and is not connected to the grid through a generator, the test train is not limited to grid speed thus providing flexibility for off-design tests and simulation of a variety of ambient conditions. Additionally, the GE team was also able to operate the test rig under real frequency deviation conditions through rapid load and speed changes, as such applying the impact of real grid events for the first time on a large 9HA turbine.
Operational flexibility extension in the low part load range for combined cycle plants with sequential combustion gas turbines
Stefano Bernero, Dirk Therkorn, Martin Gassner, Vincent Lonneux and Mengbin Zhang
Flexible power generation becomes increasingly important in highly competitive and volatile energy markets as a result of the increased use of intermittent renewable sources. A new operation concept has been developed to allow a significant reduction of CO emissions in the low part load range of the GT24/GT26 engines by individually switching on/off the reheat burners in the annular combustor. This option shows unique potential in case of sequential combustion technology, since the high inlet temperature into the reheat combustor results in moderate temperature spread in the downstream components.
Industrialisation of 3D printing (additive manufacturing) for gas turbine components repair and manufacturing
Vladimir Navrotsky, Andreas Graichen and Hakan Brodin
During the last years, a new revolutionary way of manufacturing (Additive Manufacturing, AM) has emerged the industry and is considered as a game-changer. In contrast to traditional manufacturing where volumes of material are subtracted by e.g. milling, drilling, electrical discharge machining (EDM) etc., material is added by a smart use of laser or electron beam energy. Additive Manufacturing opens up a new dimension in integrated design and manufacturing. This technology enables manufacturing and repair of gas turbine components faster and at the same time with higher functionality and performance of the components. Another recent example of SLM application at Siemens is the manufacturing of advanced design burner swirls for industrial gas turbine SGT-750.
Status of technology development of solar-hybrid gas-turbine systems
Uwe Gampe, Manfred Freimark, Stefano Giuliano, Sven Boje, Reiner Buck, Christian Felsmann, Stephan Heide, Michael Puppe, Ulrich Langnickel and Oliver Lammel
Solar tower power plants with primary feed-in of high-temperature solar heat to the gas turbine cycle with fluid temperature of nearly 1,000 °C represent a promising technology for future solar thermal power plants. The joint research project HYGATE – Hybrid High Solar Share Gas Turbine Systems – delivered essential findings and results. However, there are still significant development needs with regard to solar and power plant components and their system integration.
Characterisation and modelling of the LCF deformation behaviour of a single crystal superalloy
Eike Kohlhoff, Bjoern Buchholz and Uwe Gampe
Changing market situations concerning the cost of rare elements like Rhenium and increased requirements regarding material behaviour under cyclic thermal and mechanical loadings lead to new material investigation to increase the turbine inlet temperature for a higher efficiency of gas turbines. Canon Muskegon developed a new single crystal superalloy as a potential alternative to established first and second generation superalloys.
Comments on the international Standard ISO 14694: Industrial fans – Specifications for balance quality and vibration levels
Frank Weissbuch
The complex vibration behaviour of axial fans in air-cooled condensers – frequently used in power plants – is described. The emerging problems are explained when assessing and monitoring the vibrations of axial fans resulting from the application of the international standard ISO 14694 „Industrial fans – Specifications for balance quality and vibration levels“, 2003. The comparison with the VDI-Standard 3834 “Measurement and evaluation of the mechanical vibration of wind energy turbines and their components” (2009) reveals possible alternatives and solutions to realise a customised and differentiated assessment and monitoring of axial fan vibrations.
Mercury removal at the example of the Lippendorf power plant
Jan Schütze, Uwe Schilling. Lothar Hilbert, Josef Herbert Strauß and Thomas Hörtinger
Due to technical and fuel conditions, technologies for mercury (Hg)-removal are hardly applicable to other power station units. In case of the Lippendorf power station, different Hg-removal technologies have been tested since 2010 until the dosage of the sulphidic precipitation agent was sufficient. At first addition of activated charcoal into the flue gas upstream of ESP or the addition of a sulphidic precipitation agent into FGD suspension achieved Hg-removal rates of up to 80 %. A cumulative effect of the precipitation agent in FGD and activated charcoal doses could not be found in a combination of both methods.
Emission limits of mercury for coal-fired power plants
Alfons Kather and Mathias Klostermann
While discussing future emission limits of mercury for German coal-fired power plants, the emission limits of the USA (according to MATS) are often used as reference. However, the conversion carried out from the US units lb/GWh or lb/TBtu to μg/m3N (s.t.p.) has repeatedly resulted in emission limits which are too low. In this article, the correct conversion procedure is described.
The continuous measurement of mercury, which has been implemented yet in a few German power plants only, features a maximum allowed measurement uncertainty of 6 μg/m3 N (s.t.p.) according to the 13. BImSchV (ordinance to the German Federal Immission Control Act). A reduction of the allowable limit to a single-figure digit will significantly increase the challenges for all parties involved.
Because of this, the outmost care is required when evaluating the mercury reduction potential for German power plants.
Deposition of mercury from the flue gas and influence on characteristics of stabilisates
Herbert Pöllmann, Marko Ranneberg, Doreen Menz and Jens Ringel
To ensure the legal compliance of emission threshold values with variable coal qualities, extensive research at the flue gas desulphurisation facility at the Lippendorf power station was performed. A sulphidic precipitant and a combination of precipitant with an activated carbon mixture were used upstream of the ESP in the field tests. The residual products and the stabilisates were characterised physico-chemically and mineralogically to show a probable influence of the improved Hg precipitation on chemical composition and mineralogical phase development. The permanent bonding of the Hg-complex compounds was verified, precipitated during the Hg-precipitation in the flue gas and generated in the stabilisates.
Levelised Cost of Electricity 2015
Christian Stolzenberger and Oliver Then
The electricity buisness is currently subject to dynamic and permanent change that is driven by innovation, learning curves and modifications of the electricity generation mix. A new edition of the “Levelised Cost of Electricity (LCOE)“ was drafted under these circumstances. The fundamental idea behind the LCOE is to calculate the yearly average costs of building and operating plants and to compare these with the average energy generated each year.