Abstracts - VGB PowerTech Journal 12/2018

Safety & Health – Something new old?

Christopher Weßelmann

Occupational safety and health protection have always a high priority in power generation – safety comes first, prevention is an important commodity, health protection creates trust. Together they are important aspects of a living corporate culture, also for the external impact of the industry, in an environment in which specialists are strongly courted and it is important to attract them. VGB PowerTech took up the great interest in this topic at an early stage. The event “Emder Workshop Offshore Windenergieanlagen – Arbeitsmedizin” (Emder Workshop Offshore Wind Turbines – Occupational Medicine), which is well established in the industry, is a good example of VGB´s activities. [more...]

VGB Congress 2018: Opening address

Hans Bünting

Also in 2018, the VGB Congress offers a highly exciting programme around electricity and heat generation with interesting, energetic discussions and new findings.

Focus on people

LEAG operates the second largest lignite mining area in Germany and produces every tenth kilowatt hour of electricity consumed in Germany. The company takes an unconventional approach to occupational safety: short videos promote a more open safety culture, because everyone is part of the problem but also part of the solution.

The “VGB Safety & Health 2018 Award” was presented to the Lausitz Energie Kraftwerke AG for „ Psychological (Mental) Health & Safety Transformation of Safety Culture.

Renewable substitute natural gas synthesis integrated in power and gasification plants for energy storage

Efthymia Ioanna Koytsoumpa

The production of Substitute Natural Gas (SNG) enhances the penetration of renewable energy sources (RES) in the power, heat and transport sector. In the present work SNG production is investigated via the modelling and comparison of 3 different cases. The main target is the renewable SNG production with simultaneous energy storage via the combination of water electrolysers driven via RES electricity and integrated in power and gasification plants. The cold fuel efficiency for the three cases studied ranges between 51% to 63%, while it can highly vary according to the efficiency of water electrolysis. Higher efficiencies are achieved via the optimum heat integration. The levelized cost of SNG production is several times higher than fossil natural gas prices depending on electricity and biomass prices.

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A model-based outlook on the KWKG tender in Germany

Jan Andersson and Rana Mitra

1st December 2017, the subsidy rates for traditional CHP plants of 1 MW up to 50 MW was auctioned for the first time. The capacity of the first auction was 100 MW, after which 100 MW are auctioned twice a year. With subsidy rates of up to 70 €/MWh, participation in the auction was attractive for many companies. At the same time, however, the uncertainty was high before the auction. A central role was naturally played by the question of which results could be set in the auctions, with which bidding strategy one could place oneself successfully in the auctions and how the overall profitability of CHP projects could be presented under these framework conditions. This paper highlights the cost-effectiveness of CHP projects in the upcoming auction round. A focus is also on an outlook on possible auction results as well as possible bid strategies. The aim is to provide information to market players through a clear model-based approach, and to assist them in the decision-making process.

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The story behind Plant Performance Enhancement

Frank Schulze, Hardy Hilliges and Marco Hacke

The target of Plant Performance Enhancement (PPE) is to check the equipment. Based on the knowledge, which stress power plants are exposed to, they will be checked and limbered up for the competition. The key words are: flexibility, efficiency and availability. All essential components, the terms and conditions will be reviewed to develop an integrated concept. It is commonly known, that investments (CAPEX) are hard to justify and execute. For this reason there is new approach: PPE starts with an advance input and together with the long-term operation experience money saving potential will be uncovered, quantified and measures to gain those savings suggested.

The industrial steam turbine as an actuator in the future energy grid

Kristin Abel Günther and Christian Scharfetter

The increasing share of fluctuating renewable energies in the electrical grit requires measures for stabilization. The combination of diesel or gas engines, gas and steam turbines as well as energy storage systems in combination with wind and solar power plants form micro grids and hybrid systems enabling the desired supply reliability in an environmentally friendly way. The construction of the steam turbines has to be adapted to the desired operating profiles to achieve the required quality even with fast load changes and different load points. Decisive for the long-term success of such plants is the planning on the basis of a realistic operational profile and an optimal coordination of the power plant components. MAN has repeatedly realized the construction of combined cycle power plants and is in a position to offer all generator drive machines from its own product portfolio. The plants are then accompanied with service over the entire life cycle of MAN.

Incineration-related formation and avoidance of ammonia emissions in circulating fluidised bed combustion plants

Stefan Zeltner

Among to the NH3 slip, emissions of ammonia can also result out of oxygen deficiency conditions in the combustion chamber of fluidized bed incinerators. Due to the current lack of oxygen, the fuel-bound nitrogen is, amongst others, converted to ammonia instead of nitrogen oxide. With the application of an online-method of balancing processes, strongly fluctuating heating values of the fired waste could be determined at a fluidized bed incineration plant. This circumstance leads to a varying oxygen depletion which results in an unsteady oxygen concentration in the raw gas. Thus, values of less than 1 Vol.-% are measured. In addition, the delayed detection of oxygen leads to a further limitation of the provided secondary air during these periods which also influences the oxygen concentration negatively and enforces the linked generation of ammonia. To avoid these effects, there are both, active modifications (such as the revision of the crane merge program) and reactive modifications (e.g. the adjustment of the secondary air supply) to be considered.

Description of the fuel transport in the feeding area of waste incineration plants
Part 2: ram feeder & feeding area

Martin H. Zwiellehner, Florian Grafmans and Ragnar Warnecke

On incineration plants for residues or other heterogeneous fuels, three different fuel feeding methods are used basically: ram feeder, travelling grate feeder and spreader stoker. Travel-ling grate feeding systems are not built anymore because of their high maintenance costs and spreader stoker feeding systems are more common in smaller-scale (biomass) plants or fluidized bed incinerators with rather homogenous fuels. Therefore the focus shall be on the ram feeder types. The present 2nd part is dealing with the feeding systems of grate stoker plants which are quite common for MSW incineration. The goal is to find a method which makes it possible to calculate the mass flow of any ram feeding system only by having the construction data.

Condition and lifetime monitoring of boiler components and piping systems at high temperatures

Kai Bauerbach and Paschalis Grammenoudis

Monitoring of power plant components used in the boiler area as well as in high temperature piping plays an important role. The currently new power plants utilise significantly high steam parameters and thus a lower design reserve. Lifetime calculation is based on temperature and pressure loads according to the European standard EN 12952, assuming no influence by additional system loads on the piping system. Within advanced lifetime monitoring systems implemented in power plants, this long-term monitoring of the pipeline performance is conducted via additional measurements of forces and displacements. This kind of monitoring allows detection of the ‘as planned’ behaviour of the piping system and of inadmissible deviations from planned operation which can affect the lifetime. This enables to react early to eliminate malfunctions.

Measures against slagging and contamination of heat exchangers in lignite-fired power plant boilers

Manuela Neuroth, Michael Schüngel, Manfred Saigge and Matthias Dohrn

Over the last decades, RWE Power AG has developed a concept for Rhenish coal qualities, to reduce deposit-based boiler incidents. For this, before excavation Rhenish mines subdivide their lignites by geological, chemical and mineralogical properties and after that, deposition as pure quality or mixing to suitable qualities follows. In case of critical compositions, the mineral content can cause fouling, sintering or slagging inside the boiler, each in distinct zones. Here, oxidic multicomponent systems are the thermochemical basis. The presented concept for coal qualities combines these correlations in a usable way, but is always considering some additional rules, which are also presented in this article, to minimize coal-related boiler problems. Therefore, securing and controlling of the primary coal properties to guarantee correct coal qualities is recommended via on-line analysis.