Abstracts - VGB PowerTech Journal 9/2018

Digitisation in power generation

Christopher Weßelmann

The advancing digitisation is undoubtedly one of the great challenges and also one of the great new opportunities for our further development. One generation ago, digitisation consisted of feeding computers with punched cards to speed up computing processes. Today, for example, we can use our voice to trigger orders or remotely control the room temperature in our homes. [more...]

Successful vibration analysis on a 200 MW pump turbine in Luxembourg

Patrick Tetenborg, Johann Lenz and Gilles Nosbusch

The pumped-storage power plant in Vianden, Luxembourg, was expanded in 2014 with an additional 200 MW pump turbine. Ever since it was put into operation, a distinctive 150 Hz vertical vibration occurred in turbine mode in the upper range of performance, which was clearly audible as an individual note in the underground cavern. The results of the performed measurement and analysis showed that an acoustic resonance (Helmholtz resonator) within the hollow hub could be the cause. To prove this theory, air was injected in the critical area and so the acoustic system should be detuned. This measure was successful and so the 150 Hz vibration phenomenon could be eliminated. Another solution with modified hollow hub design has approved the accuracy of this root cause analysis and shows a more energy-efficient solution for the long-term operation.

A concrete solar collector – from design to assembly in full scale

Patrick Forman, Sebastian Penkert, Dirk Krüger, Peter Mark, Jürgen Schnell, Klaus Hennecke, Joachim Krüger and Reinhard Dasbach

The need for renewable energy is becoming more and more important. The most mature technology in case of solar-thermal power plants are parabolic trough collectors concentrating solar radiation. These troughs are mainly built up as steel frameworks with pointwise supported, curved mirror elements. In the project ConSol (“Concrete Solar Collector”) a solar concrete collector as a shell made from high-performance concrete has been developed and built up in full prototype scale. The idea was to design a holistically optimized collector. Thus, a process was set up from conceptual form finding, considering deflection based loads, to assembly of the collector made from various precast elements, mounting parts and an improved PVD coated mirror material on electrochemical polished aluminium strip. By means of digital close range photogrammetry the collector has been optically evaluated and the performance and costs of the whole collector is compared to benchmarks of existing collector technology.

Efficient storage of electricity – Power to gas with double waste heat utilisation The “Energiewende” requires electricity storage

Ulrich Bohn and Florian Lindner

According to the German government’s energy concept, the share of renewable energies in the German electricity supply is expected to increase continuously to 80 % by 2050. However, the share of wind and solar energy also increases volatility, because electricity is produced even when we do not need it. This leads to more significant deviations between electricity supply and demand compared to today. Electricity from renewable sources that cannot be used directly will therefore increase significantly. Under these conditions, the importance of electricity storage facilities will increase. For long-term electricity storage, power to gas is a sensible option that has now been well researched in many pilot projects.

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In-house production of high-resolution spherical panoramas in a technical environment

Ansgar Schlump

The benefit of 360 ° panoramas for work planning and preparation in the technical environment is undisputed. However, the requirements for resolution and sharpness in this area exceed the possibilities of the technology available in the consumer electronics. However, the self-creation of high-resolution spherical panoramas by operating personnel is not only useful, but also technically possible, as the example from the Emsland nuclear power plant shows.

Circulating bed FGD – Operating experiences optimization versus availability

John Wall

ESB Moneypoint in Ireland consists of three 315MW coal fired units commissioned in the mid 80’s. In 2008 the boilers were retro-fitted with dry bed recirculation flue gas de-Sulphurisation (FGD) plant and SCR (Selective Catalytic Reactor) with U2A (Urea to ammonia) supplying ammonia reagent. Initial commissioning was beset by delays due to multiple issues primarily with the FGD process with acceptable levels of abatement compliant with LCPD limits were not realised until 2010. While compliant with LCPD (Large Combustion Plant Directive) the plant would not meet the more stringent requirements of the IED (Industrial Emissions directive) post 2016 and significant improvement works were required such that the station could continue to operate in this new operating regime. While improvement works were carried out on most elements of the FGD abatement process this paper will concentrate on the operating characteristics of the dry FGD as well as the controls required such that reliable operation is achieved.

Reduction of corrosion damage through firing evaluation and process modifications

Thomas Brunne, Andreas Mengel, Steffen Griebe and Helmut Bischoff

During the major overhaul of a 900 MW lignite-fired unit at the power plant Boxberg, a damage at the membrane wall of the furnace hopper was detected. After a detailed evaluation of findings and documentation of the extent of the damage, pipe samples and deposits were analyzed by the TU (Technische Universität) Bergakademie Freiberg. They confirmed our assumption that the damage had been caused by sulfur-induced high-temperature corrosion. Afterwards and in order to prevent any further damage, the exact cause of the damage had to be found out by thorough examination of all relevant operation settings as well as additional measurements. During the inspections and measurements, deviations from the design conditions were detected. They included both altered fuel properties and deviations in the combustion set-tings. In the course of this presentation, I will deal with research results and these measurements in detail. Based on the measurement results, selected process modifications have been executed to prevent any further damage of the membrane wall.

Model-based evolutionary algorithm for optimization of gas distribution systems in power plant electrostatic precipitators

André Schagen, Frederik Rehbach and Thomas Bartz-Beielstein

Electrostatic precipitators (ESP) are used for dust separation at various industrial processes. The efficiency of an ESP depends mainly on the gas velocity distribution within the separation zones. To ensure a sufficient flow field, a gas distribution system (GDS) is installed in the ESP inlet hood. Such a GDS consists of several hundred elements, e.g., perforated plates with different free cross sections, deflecting baffles and blocking plates, which leads to a very high number of possible GDS configurations. Usually a heuristic approach in conjunction with CFD simulations and cold flow measurements by hand is used to find a suitable GDS configuration. This results in an acceptable but not optimal gas velocity distribution especially at the inlet area of the first separation field. To find a better or even an optimal GDS configuration, a detailed CFD model of an ESP and a computational intelligent and automated approach based on an evolutionary algorithm is developed.

Microbiological analyses of cooling water according to 42nd BImSchV

Herbert Lindner and Sebastian Hahn

On August 19th, 2017, the 42nd BImSchV came into force. The regulation aims to ensure hygienic operation of evaporative cooling systems, cooling towers and wet scrubbers. All of these plant types can be sources of legionella-containing aerosols, which can lead to infections in the respiratory tract of humans when inhaled under certain conditions. The aim of the 42nd BImSchV is to minimize this risk of infection as much as possible. The 42nd BImSchV has led to many operators, authorities and laboratories dealing in more detail with the subject of analytics. The recommendation published by the Federal Environment Agency (UBA) for the sampling and detection of Legionella in evaporative cooling plants, cooling towers and wet scrubbers which was published almost at the same time, has led many laboratories to change their testing methods.

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Flue gas flow rate calculation for mass emissions reporting. Part 2: Verifying flue gas flow rate calculation, by means of stack testing and data evaluation, to EN-ISO 16911:2013

David Graham, Jonathan Spence, Frans Blank, Patrick Wolbers, Nathalie Faniel and Jurgen Annendijck

Operators of combustion plant need to know the flue gas flow rate to calculate the mass release of pollutant emissions. For many standard fuels, the calculation of flue gas flow rate gives reliable results, with a defined uncertainty, using relatively simple procedures, thus avoiding the need for a flue gas flow monitor. The calculated dry flue gas volume is combined with emission concentrations that are reported on a dry basis. When pollutant concentrations are also measured on a dry basis, as is often the case for large combustion plants, this avoids the measurement of water vapour and hence an additional uncertainty. This publication is the second of a series of three VGB Research Projects on “Flue gas flow rate calculation for mass emissions reporting”.