Abstracts - VGB PowerTech Journal 12/2012

From October 10 to 12, 2012, the VGB Congress “Power Plants 2012” took place in Mannheim/Germany. It was themed “Security of Supply - Power Generation at the Crossroads?”. Some 1,000 experts from 30 countries took the advantage provided by the largest European technical congress on electricity and heat generation. The experts discussed current issues in the sections on “nuclear power”, “storage and flexibility”, “efficiency and flexibility” as well as “renewables” facing the challenges of current and future electricity and heat generation in Europe.

Christophe Vallée*, Dirk Lucas, Akio Tomiyama and Michio Murase

Stratified two-phase flows were investigated in two different models of the hot leg of a pressurised water reactor (PWR) in order to provide experimental data for the development and validation of computational fluid dynamics (CFD) codes. Therefore, the local flow structure was visualised with a high-speed video camera. Moreover, one test section was designed with a rectangular cross-section to achieve optimum observation conditions. The phenomenon of counter-current flow limitation (CCFL) was investigated, which may affect the reflux condenser cooling mode in some accident scenarios.

*(Dr. Christophe Vallée was awarded the Heinrich Mandel prize at the VGB Congress
“Power Plants 2012“)

Andreas Ehlert, Norbert Haspel, Michael Fuchs, Uwe Kleen, Stefan Nießen, Wolfgang Steinwarz and Hannes Wimmer

In response to tighter public research budgets for nuclear research and development, eight major German companies as well as universities and research institutes united in the Network for Competence in Nuclear Technology (German: Kompetenzverbund Kerntechnik) have decided to intensify their co-operation with the aim to maintain expertise by conducting joint research projects. This paper pointed out the necessity to maintain and develop nuclear expertise in spite of the decision to phase out nuclear energy. Based on the recommendations given in the position paper, the heads of research and development of the eight companies agreed as to where the focal areas of nuclear research will be in the future from the industry’s perspective in the context of the German turnaround in energy policy.

The economic significance of older turbo-sets lies primarily in their steadily increasing share of the total power generated worldwide. This is reflected by a trend in which plants originally built for base-load operation are increasingly being used for variableload or even continuous start-stop operation. This change occurred in the
60 Hz US market more than 25 years ago. The paper gives an overview about numerous solutions for refurbishment, life extension, retrofits and upgrades developed for generator rotors, stators and exciters. These are no prototype solutions, but solutions which already work reliably for the 60 Hz market for many years and which can be applied and adapted of the same problems of the 50 Hz market.

Michael Nies, Peter Niemeyer, Bernhard Röper, Joachim Werther and Ludwig Müller

Until the 1990s, fluidised bed combustion was restricted to 350 MW of output, today, plants up to 600 MW are possible. The most important German concepts are presented by selected examples. These comprise mainly co-generation plants and industrial power plants with process steam extraction, biomass-fired plants with 20 MW as well as waste incineration plants and sewage sludge mono combustion system. According to market conditions, it is to be expected that decentralised plants with heat utilisation and flexible duo unit plants as well as fluidised bed combustion plants are going to be competitive.

Wojciech Nowak

The use of fluidised bed systems for power generation is a rapidly growing technology in Poland. The ability of fluidised beds to burn a wide variety of fuels while meeting strict emission control limits makes them an ideal choice for burning such fuels as high-sulphur coal, lignite, peat, oil, sludge, pet-coke, gas, and wastes. The paper presents the current state of fluidised bed boilers in Poland. Special emphasis is placed on operating experience from the largest circulating fluidised bed boilers which have accumulated for more than ten years of operation.

Hairui Yang, Guangxi Yue, Junfu Lu and Hai Zhang

CFB combustion technology has been well developed in China since the 1980s because of the continues need of coal fired-power. The utilisation of coal washing waste and the economic reduction of SO_x and NO_x emissions are the major two driving forces for CFB combustion technology. Chinese researchers have made great effort to understand the fundamentals of CFB theory and practiced their theory in CFB boiler development. They support Chinese boiler works to develop series capacity CFB boiler until the world largest 600 MWe supercritical CFB boiler.

Krzysztof Sadowski

The paper presents the experience gathered with the operation of a stationary fluidised bed boiler installation. Apart from presenting the basic information concerning this installation, the work compares two boilers, the original design of which was identical and based on the OP-140 pulverised coal combustion. One of the boilers was subsequently converted to the OFB-105 type and adapted to stationary fluidised bed biomass combustion. The difficulties encountered by renewable energy producers - related to obtaining fuel and to fulfilling formal and legal requirements - are also being discussed.

Gürkan Atmaca, Werner Stratmann and Birgit Wortmann

The Iskenderun power plant is located at the bay of Iskenderun in the Province of Adana in the south of Turkey. Two units with a total output of 1,210 MW are operated. The annual fuel - imported coal from Colombia and South Africa - consumption amounts to about 3.3 million tonnes tce. To meet the SO_x and particulate
limits values it was necessary to improve the performance of the FGD scrubber and the electrostatic precipitator (ESP). In the first step, the potential of a fluid flow optimisation of both the scrubber and the ESP was determined by simulating the “as build” situation (reference cases) with a computational fluid dynamics (CFD) code. In the second step, several possible variants of component modifications and structures were analysed and evaluated. In a last step the most improving modifications were proposed.

Leming Cheng, Chun Yang, Xinglong Zhou and Kefa Cen

Suspended heat transfer surfaces are widely used in CFB boilers. Industrial operating prob-lems with suspended heat transfer surfaces including heat transfer panels in the furnace and the hanging tubes facing the gas flow in a back pass are described. Erosion and uneven temperature distribution of the surfaces are the main reasons for tube bursting. Since the heat transfer of the suspended heat transfer surfaces is one of the most important root causes to surface problems, experimental research and theoretical work was carried out. A 3D dynamic heat transfer model was established based on CFB 3D hydrodynamic simulation and a software was developed to improve future CFB design.

Yousef Alipour, Peter Viklund and Pamela Henderson

Increasing use is being made of biomass as fuel for electricity production as the price of natural wood continues to rise. Therefore, more use is being made of waste wood (recycled wood). However, waste wood contains more chlorine, zinc and lead, which are believed to increase corrosion rates. Corrosion problems have occurred on the furnace walls of a fluidised bed boiler firing 100 % waste wood under low-NO_x conditions. The deposits have been collected and analysed in order to understand the impact of the fuel.

Jonas Klingspor

Since the introduction of wet FGD systems, emission standards have gradually been tightened. Hence, older FGD systems are being asked to provide performance and reliability well beyond the initial design. Wet FGD systems are also required to control more than emissions of sulphur dioxide. URS has been involved in research, development, testing, and upgrade of wet FGD systems for more than 30 years. URS has demonstrated that every wet FGD system regardless of design and configuration can be modified to achieve uninterrupted operation.