Abstracts - VGB PowerTech Journal 6/2015

GKM unit 9 – Construction of a 911 MW coal power plant in an urban area

Ulrich Ehmann, Hubert Dorn, Gernot Mieth and Rolf Scheinost

Grosskraftwerk Mannheim Aktiengesellschaft (GKM) is running one of Europe’s most efficient hard coal-fired power stations. Its exceptional inner-city location had massive effect on the planning of buildings and the construction of unit 9. From the very beginning, the problems of planning had to be solved as well as possibilities of construction work and assembly had to be analysed. GKM unit 9 – an exciting project – placing high demands on all people involved and representing an investment into the future of GKM.

Use of state-of-the-art high-temperature materials in GKM unit 9

Klaus Metzger

Grosskraftwerk Mannheim AG is building one of the most modern hard coal power stations in the world. The newly erected unit 9 is characterised by steam parameters of 600/610 °C and 290/58 bar, and an efficiency of 46.4 %. The operation in this temperature range requires an adequate material concept. High-temperature materials are used. The worldwide manufacturing of components resulted in numerous challenges for quality assurance of GKM which was supported by VGB PowerTech and TÜV SÜD. T24 is taken as an example outlining the relevant requirements for manufacturing welded joints. The application of an adapted and foresighted concept of quality surveillance is demonstrated for the material P92.

Health and safety at work at the large construction site of new build unit 9 of the Grosskraftwerk Mannheim AG

Michael Hilger

The large construction site of unit 9 of Gross-kraftwerk Mannheim (GKM) poses particular challenges to be met by the operator GKM as regards health and safety at work. During normal power plant operation, GKM has sole responsibility for their staff. However, health and safety at single batches and lots of the construction site have to be guaranteed by those contractors and sub-contractors executing these jobs. In order to ensure joint proceeding in all areas of health and safety at work and to guarantee coordination with contractors and sub-contractors, rules have to be established – valid for all parties involved – distributed and accepted before setting up the construction site. Special challenges to be met by safety and health and the solutions for the large construction site are being presented.

Technical development of flue gas cleaning and waste water treatment plants

Norbert Eimer and Joachim Fahlke

More and more stringent environmental regulations require different techniques of flue gas cleaning to be developed in recent years. The limit values for sulphur dioxide (SO2), nitrogen oxides (NOx), dust and heavy metals (especially mercury) became more stringent with each new power station project. Because of the new Industry Emissions Regulation Directive (IED), a process has been released with the result that the environmentally most acceptable technology was declared as “best available technique (BAT)”. Mannheim power station has extensive experience with flue gas cleaning systems installed at the units 3, 4, 6, 7 and 8. Process engineering of flue gas cleaning is described.

Refurbishment and flexibilisation of high-voltage assets for the integration of a new power plant

Werner Eghardt, Winfried Eberbach and Georg Rombach

The business portfolio of Grosskraftwerk Mann­heim (GKM) comprises electrical power and district heating generation. For German Railway (DB Energie GmbH) we are an important supplier of 16.7 Hz traction current. The power plant output with the latest unit 9 amounts to 2,146 MW electrically and 1,500 MWth. The electrical generation devices are directly connected over 110-kV- and 220-kV-switchgear stations to the transmission grids and are part of the of the DB Energie GmbH energy supply. The integration of a new 911 MW unit requires thoughtfully adjustments also at the surrounding high-voltage assets.

Increasing the flexibility of operational scheduling for a large-scale CHP plant used for generating district heat and electricity in order to meet the varying market demands

Matthias Meierer, Roland Krupp and Rolf Stork

The substantial changes in the structure of German power supply plants pose high demands on the flexibility of the operational scheduling of conventional thermal power plants. Grosskraftwerk Mannheim AG is a power plant company that is operating a plant for combined power and district heat generation. The paper describes some measures which have been taken to improve the plant’s operational flexibility. In addition, the associated technical systems and their functions, as well as the state of ongoing projects are outlined. Special focus is placed on topics related to issues such as “district-heat storage unit of the new unit 9, flexibility of operational scheduling, and efficient CHP plant operation”.

Waste-to-energy confronted with current legal acts and targets for recycling

Martin Treder

Thermal waste utilisation stands at the interface between energy conversion and waste management. Waste as a fuel is hardly comparable to conventional fuels. The waste management sector is confronted with non-transparent waste streams, inconsistent legal terms and contradictory forecasts. The different waste streams and recovery methods have to be scrutinised using measurable quality criteria. To make this possible, waste streams have to be made transparent, the right quality criteria have to be established and the scope of assessment has to be extended to include more sustainability aspects. Quality not quantity is the dogma of an effective recycling industry. What is left after that should undergo a high-quality energy recovery.

Sea water ingress during the commissioning of an USC power plant

Anthony Senécat and Roger Ertryckx

During the commissioning of an ultra supercritical coal-fired power plant an event occurred in the condenser which resulted in a serious ingress of seawater in the water-steam cycle. The plant was operated more than 10 hours with this sea water ingress leading to uncontrolled chemistry in the whole water-steam cycle, except for the steam turbine which was in bypass mode. In the aftermath of the incident, a root cause analysis was performed to determine the origin of the pollution and to understand the chemistry trends during the incident. Questions about the integrity of the boiler were raised as the incident occurred a few weeks after the thermal passivation so the protective oxide layer might have been washed out during the incident. Some tube samples were extracted for metallographic examinations.

Developments in spray-type deaerator applications

Bart Bramer

The spray-type deaerator has a very flexible design and will effectively remove dissolved oxygen from the water-steam cycle. Oxygen concentrations of 5 ppb or less can easily be obtained and can significantly extend boiler life. The single vessel design has a small footprint, is easy to control and minimises the number of pressure parts to be used. Various streams can be collected directly in the deaerator and contribute to the deaeration process. The application of deaerators in the water-steam cycle of directly fired boilers, HRSGs, closed loop cycles, solar power installations, nuclear power boilers and several special applications are described in detail.

Fire detection by means of special fire detection systems

Christian Scheuer and Simon Trippler

This paper describes the planning process of fire detection systems for special applications and the essential requirements for a fire detection system. Therefore, the detailed contents of a so-called “fire detection concept” will be presented and the requirements for the planning process of a fire detection system are outlined. In this connection the special requirements for the use of semiconductor gas sensor array smoke detectors for very early fire detection will be considered. Semiconductor gas sensor array smoke detectors are able to detect pyrolysis gases occurring in starting smouldering combustions, even long before any flames occur, like in a test fire. The planning process and the implementation of those semiconductor gas sensor array smoke detectors require dedicated basic evaluation, which should be summarised in a so-called “fire detection concept”. The result of the concept represents the basis for a successful planning process.

Rescue chain offshore wind – Framework conditions, medical incidents, first aid and emergency medical services

Nils Weinrich, Dirk Dethleff, Markus Stuhr, Maja Nielsen and Christian Jürgens

Medical emergencies during construction and operation of offshore wind farms pose particular challenges to all parties involved. Besides workplace-specific aspects, especially the distance to mainland needs to be considered, which finally determines the arrival time of professional help and the transport time to the nearest appropriate hospital. Additionally, environmental factors influence the accessibility of the offshore structures as well as the operational capability of the rescue units. A first analysis of medical events in German offshore wind farms is presented in addition to the individual steps of medical emergencies, i.e. their operational scheme.

The new VGB-Standard VGB-S-513-00: Internal cleaning of water-tube steam generating plants and associated pipework

Adelja Markert, Christiane Holl and Peter Jentsch

Before commissioning new plants, it is critical to ensure that the inner surface of the water- and steam-carrying plant components and pipes is clean. If the deposit build-up during operations negatively impacts the heat transfer and efficiency of the plant, cleaning of the operational equipment may be required (i.e. chemical cleaning). To implement these measures, a standard, (VGB-R 513) was elaborated in 2000. This standard constitutes “a compilation, analysis and reconciliation of various company-specific guidelines, expertise and opinions.” The VGB-S-513-00-2014-07-EN was published in German (as VGB-S-513-00-2014-07-DE) and English.