Abstracts - VGB PowerTech Journal 6/2016
Likeable electric
Markus Bresler
As a train commuter, I regard myself as an expert in the area of ‘editorials’. Among the journals I buy, I also often look at other journals on offer at the news kiosk. So I spend hours of waiting time reading, more often than not the editorials. Comparing those editorials with those of previous editions of VGB PowerTech, I doubt that my consumer knowledge helps me that much. Consulting, as a last resort, the Wikipedia website, ‘editorial’ is described as “an opinion piece written by the senior editorial staff or publisher of a newspaper, magazine, or any other written document”. The German-language site of Wikipedia adds the information that, for a long time, it was the domain of Anglo-Saxon newspapers to recommend how readers should vote in elections. In the recent past, more and more European papers have followed this tradition without hesitation.[more...]
A new approach to distributed energy generation – An overview
Thorsten Krol
Today, power plants are operated in an increasingly complex grid with a constantly changing consumption structure. The increasing generation of wind and photovoltaic energy, which have priority infeed, results in a highly changeable residual load that generally has to be balanced out by fossil fuel-fired power plants. This increases the wear on several components in the power plant, a situation that can be dealt with using suitable modernization measures. Furthermore, backup solutions for the volatile renewable energy sources must be found that are also as climate-friendly as possible. Gas turbines are the ideal solution because of their high efficiency levels and flexible operation. They can feed energy into both the high-voltage network and the distribution network and thus can best meet the challenges of distributed power generation dominated by renewable energy sources.
Power-station maintenance – Which strategies and tools are necessary?
Hans Christian Schröder and Jörg Schenkel
Competitive pressure and the energy transition are also affecting the area of power-station maintenance. More flexible modes of operation are associated with higher cyclic loads, which are more demanding on the material and plant components. Given this, servicing and maintenance must also be reconsidered. Today’s plant managers are increasingly reliant on a risk-oriented approach. Nevertheless, power stations repeatedly suffer failures and defects, sometimes of major proportions. One of the leading causes is inadequate maintenance. Maintenance is certainly one of the key factors determining operating costs. However, it should be optimised for the specific plant in question and not focused on cost reductions alone. Safety, costs and use must be in balance. This requires a strategy that takes note of the special features of the plants.
Extended requirements on turbo-generators due to changed operational regimes
Matthias Baca and Ana Joswig
The operating regimes are changing from base load to flexible peak load in conventional power plants, which has to be taken into account worldwide. Due to the new requirements it is evident that generators are not operated in a steady-state thermal condition anymore. The high volatile operating conditions of the electrical grid due the integration of renewable energy sources result particularly in an increase of number of Start-Stop Cycles, numerous and steep load ramps and load changes of the turbines. Frequent thermal cycling creates increased thermo-mechanical stress and consequential accelerated aging of the shaft train components. This impact must be considered in the design of future products to avoid unexpected and cost intensive outage periods. Current operating regimes and their impact on turbo generators are evaluated. Possible solutions and mitigations are analysed for a reliable and cost optimised operation under consideration of current trends in the energy markets.
Maintenance and optimisation procedures on two circulating fluidised bed boilers after switch-over of the coal type
Mirko-Christian Heidebrunn and Hans Schäfer
At the beginning of the 1990s two circulating fluidised bed units from ARGE Lentjes-Lurgi went on stream at the Chempark Leverkusen site. In the course of operation the units were adapted and optimised to handle the coal from the Ruhr region used at the time. With the phasing out of coal production, the procurement of Ruhr coal was at first limited and in recent years impossible. The need to handle the coal available on the global market and its varying composition (ash content and type, volatiles content etc.) means that the units now have to be modified and readjusted. Particular problems are encountered in the areas of the coal path, the nozzle grate and desulfurisation. The maintenance outlay has increased while plant availability has decreased. The application of an IT-supported combustion chamber model is designed to visualize the processes that occur in the combustion chamber and thus enable an optimisation of the unit.
Blade seal faces of Kaplan turbines: In-situ refurbishment
Martin Proll, Frank Hoppe and Christoph Fleischer
Energy produced by hydropower plays a significant role in the realization of the ambitious European climate protection and energy policy objectives. Although the potential for the construction of hydropower plants has by far not been exhausted, its realization is addressed hesitantly because of high costs of investment and lengthy planning and permitting processes due to special consideration of ecological aspects. Subsequently, most of existing plants have been in operation over a number of decades. A reliable and safe operation over such a long time period can only be guaranteed by way of regular maintenance measures. The costs involved can be reduced significantly through the utilization of innovative technological measures. An example for this is the patented process used by Uniper Anlagenservice in the refurbishment of sealing surfaces of the rotor blades of Kaplan turbines that are mainly used in run-of-river power stations.
Noise control measures at power plants – reduction capabilities from a supplier’s point of view
Michael Daub and Anton Utzschneider
Sound requirements at power plant projects are continuously increasing. A reason might be the location of power plants in regions where the initial level of sound pollution is already exceeded. A second issue is the expectation of an increasing number of distributed power plants “close to habitants”. The third issue is the intense debated impact of low-frequency noise and its attenuation. Consequently, there are two main questions: a) Are the sound reduction measures suitably estimated? b) Are the available noise reduction capabilities exploited well? This article tries to find answers to this challenge for plant engineering, consultants and suppliers.
Thermodynamic gas state calculation for cavern storages − Simulation software PVT tool based on physical-statistical ARMA-models
Burkhard Leide and Fabien Favret
Energy transition requests increasing importance from gas storage facilities. Strategic energy reserves on the basis of a greenhouse-gas friendly fuel pairs with the capability to provide fuel to grid-balancing power stations (mostly gas-turbines) within short time. The latter task is predominantly executed by fast cycling man-made salt cavern storage facilities. In order to guarantee safe operation of the underground structure, operators must closely monitor gas pressures and temperatures to the mining authority. On the contrary to complex FE modelling and computer processing needs, the here presented PVT Tool software exclusively relies on Excel Solver routines and executes on common desktops. The PVT Tool has been developed on an EDF/EnBW co-owned UGS facility in Northern Germany and is now into its 2nd year of utilisation in the control room. Meantime, two additional sites have been provided with successful history data matching.
New technology for monitoring fouling deposition in coal fired boilers
Naftaly Menn and Boris Chudnovsky
New technology is described which allows to get real time data on thickness and reflectivity of fouling deposition on the water wall tubes of coal fired boilers. The data enable to monitor local heat transfer along the furnace wall and to estimate the impact on FEGT and cleanliness factor of the unit. An optimal procedure for cleaning of the furnace is possible. Examples of measurements demonstrate that fouling dynamics can vary significantly inside the furnace. Two different types of deposition can be seen: one with low thickness and steadily growing and the other based on big lamps of unburnt materials.
Recycling of used SCR catalysts
Frans van Dijen and Yoshinori Nagai
Used Selective Catalytic Reduction (SCR) catalysts are best regenerated. When used catalysts are deteriorated from a mechanical point of view, catalyst regeneration is not possible, and disposal must be considered. Land filling of used catalysts is discouraged by EU legislation. This paper is about other methods for disposal of used catalysts and mainly focussing on “recycling”. This recycling of used catalysts proved technically feasible and a first financial analysis is presented. There is discussion whether used catalysts is hazardous waste or normal waste.
Acquisition and maintenance of competencies for safety and occupational health
Detlef Michaelis and Thomas Leuschner
The energy transition and the demographic change are just some of the major challenges for the German energy industry. It is the strategic goal of producers to position the companies according to the changing conditions of the energy market. The most important resource in the value added chain is man as „production factor“. As a consequence, companies will have to support their employees to protect their market position. The hitherto positive development of occupational health and safety in the energy sector must not stagnate.
The German “Energiewende”
Evaluation after the Paris-Agreement
Eike Roth
The World-Climate-Summit 2016 in Paris agreed to exacerbated goals for climate protection. This paper will scrutinize whether Germany can comply with its Paris-obligations by continuing the ongoing German “Energiewende”. The result is clear-cut: The German “Energiewende” is inadequate. Due to the cap-and-trade system of the EU the “Energiewende” can in no way contribute to climate protection.