Abstracts - VGB PowerTech Journal 11/2006

Switching Unit 6 of Grosskraftwerk Mannheim AG from Natural Gas to Hard Coal Firing

Matthias Meierer, Gernot Mieth, Bernd Krohmer, Hellmuth Brüggemann

The fuel oil-S-fired steam generator of the 300 MW unit 6 of Grosskraftwerk Mannheim was commissioned in 1975. Unit 6 can also be operated with natural gas. The unit was used for medium and peak load operation and since the mid-80ies the unit had only been run for several hours per year. In 2005 the furnace was switched to hard coal with successful redesign and refurbishment of major plant components. The unit has been on the grid since December 2005.

Modernisation of Steam Turbines at the Farge and Heyden Power Plants

Andreas Willrodt, Jürgen Schaper, Helmut König, Rainer Schramm

E.ON Kraftwerke has been performing highly extensive plant modernisations for years to increase cost-effectiveness. Since 1998 the efficiency has been increased through enhancements by approximately 245 MW. This additional capacity is available without any increase in fuel consumption. Especially the turbine-generator and the associated condenser hold potential for extensive improvements. At the hard coal-fired power plant sites of Farge in Bremen and Heyden in Petershagen near Minden, advanced turbine components were last commissioned in 2004 and 2005, respectively.

Increased Output of Steam Generators by Different Firing Coal Qualities through New Intelligent On-load Cleaning Technology

Stephan Simon, Manfred Frach, Bernd Jochum, Axel Lang

15 years ago the water cannon technique was established for on-load cleaning of combustion chambers at lignite-fired power stations. Meanwhile water cannons are the common cleaning technology also in hard coal-fired boilers as well as biomass-fired boilers and waste incineration plants. In combination with sensor-based diagnostic systems for detection of the individual fouling situation in the combustion chamber the water cannon cleaning technique can be used on demand and very effectively.

Operational Experience Gained with Unit K at the Niederaußem Power Plant

Bernd Wessel, Dieter Rüsenberg, Jens-Uwe Schlenkert, Ingo Thiele, Georg Karkowski

The lignite-fired unit Niederaußem K has been in operation since 2002. It is designed to burn a coal blend of lignites from the Garzweiler and Hambach opencast mines. The unit is operated, as designed, with this blend, which results in smooth furnace operation both as regards mills and burner. Weak points in the ash removal system were detected and are going to be eliminated.

Optimisation of Boiler Operation through Comparison of “Identical” Firing Systems - Boiler Simulations and Field Tests

Martin Käß, Thomas Sabel, Benedetto Risio, Oliver Greißl

EnBW operates two boilers at Rheinhafen-Dampfkraftwerk 7 (RDK 7) and at Altbach CHP (CHP 1) at the sites in Karlsruhe and Altbach in Germany. A systematic simulation of the pretended similar (“identical“) firing systems with a thermal load of 1200 MW revealed potential measures for an optimised boiler operation. The efficiency of the identified measures was assessed with respect to the optimisation potential using boiler simulations. The real firing process was therefore transformed into the virtual reality of a mathematical boiler model. The 3-D-boiler simulation code AIOLOS was used as simulation tool.

WTA Fine Grain Drying: Module for Lignite-fired Power Plants of the Future - Development and Operating Results of the Fine Grain Drying Plant

Hans-Joachim Klutz, Claus Moser, Ditmar Block

The process concept of WTA fine grain drying and fine grain processing was successfully operated in a test plant in the Frechen refining plant of RWE Power AG.
In an optimisation process implemented during ongoing operations, it has been possible to step up the design data by some 64%. With its high specific drying capacity, simple plant technology and comparably low investment costs, the WTA fine grain process offers all preconditions for operating the future dry coal-fired power plant with pre-drying at competitive costs and with significantly increased efficiencies.

Switching Unit 6 of Grosskraftwerk Mannheim AG from Natural Gas to Hard Coal Firing

Matthias Meierer, Gernot Mieth, Bernd Krohmer, Hellmuth Brüggemann

Modernisation of Steam Turbines at the Farge and Heyden Power Plants

Andreas Willrodt, Jürgen Schaper, Helmut König, Rainer Schramm

Increased Output of Steam Generators by Different Firing Coal Qualities through New Intelligent On-load Cleaning Technology

Stephan Simon, Manfred Frach, Bernd Jochum, Axel Lang

Operational Experience Gained with Unit K at the Niederaußem Power Plant

Bernd Wessel, Dieter Rüsenberg, Jens-Uwe Schlenkert, Ingo Thiele, Georg Karkowski

Optimisation of Boiler Operation through Comparison of "Identical" Firing Systems - Boiler Simulations and Field Tests

Martin Käß, Thomas Sabel, Benedetto Risio, Oliver Greißl

EnBW operates two boilers at Rheinhafen-Dampfkraftwerk 7 (RDK 7) and at Altbach CHP (CHP 1) at the sites in Karlsruhe and Altbach in Germany. A systematic simulation of the pretended similar ("identical") firing systems with a thermal load of 1200 MW revealed potential measures for an optimised boiler operation. The efficiency of the identified measures was assessed with respect to the optimisation potential using boiler simulations. The real firing process was therefore transformed into the virtual reality of a mathematical boiler model. The 3-D-boiler simulation code AIOLOS was used as simulation tool.

WTA Fine Grain Drying: Module for Lignite-fired Power Plants of the Future - Development and Operating Results of the Fine Grain Drying Plant

Hans-Joachim Klutz, Claus Moser, Ditmar Block

Substitute Fuels - Fuels Feeding, Production, Application and Characterisation

Asja Mrotzek, Thomas Marzi, Klaus Görner

Since June 2005 it has no longer been allowed to deposit untreated wastes on landfills. Therefore, investors are building several plants to pre-treat waste and to produce refuse derived fuels (RDF) of wastes. RDF is used in co-combustion, e.g. in cement kilns and power plants and also in mono-incineration plants. The requirements to RDF increased during last year especially for chlorine (< 0.5 mass-%). The pre-treatment for producing RDF is depending on the subsequent application (co-combustion or mono-incineration). RDF used in co-combustion needs a high calorific value, small particle size and it must fulfil high requirements to the burning behaviour. The requirements for mono-incineration are lower.

Co-inceneration of Substitute Fuels in a Circulating Fluidised Bed Combustion

Edgar Basler

Since 1986, Papierfabrik August Koehler AG in Oberkirch/Germany has been operating a circulating fluidised bed combustion system based on hard coal. In order to counter the continuously growing coal prices, efforts were made to look for solutions towards "plastic waste". From mid-2003 on, the power station obtained the permit to co-incinerate secondary fuels, i.e. secondary fuels (from commercial waste) as well as processed domestic waste can be used as fuels in addition to anthracite and fibre and paper sludge from the own sewage plant. Importance was always attached to regional recycling. After an operating period of three years, the co-incineration was continuously increased to > 11 % of the heat capacity.

Operational Experiences with Co-firing of Different Biomass Fuels

Patrick Savat

Co-firing biomass or other substitute fuels (SF) in pulverised coal-fired power plants is a technical and economical interesting choice. Advantages are among others the lower investment costs and the higher efficiency. In Belgium (Flanders) the co-combustion of coal and well-selected bio-fuels is granted with green certificates (for the electricity generated from the biomass fraction). In the framework of CO2 reduction, the Belgian regional governments have introduced a system of green certificates and quotas for green electricity. If these quotas are not met, utilities have to pay a fine that can reach 125 € per certificate not generated. In this publication the most interesting experiences concerning co-firing coal and biomass in Electrabel´s pulverised coal-fired power stations are presented.

Plasma Coatings against Corrosion and Abrasion on Pipes and Panels at Coal-fired Power Plants, Biomass and Waste Incinerating Plants

Ulrich Balting, Bodo Häuser, Thomas Weber

In today's steam generators which are applied in conventionally fired coal power plants, as well as in waste incineration plants, wear and corrosion are of major concern. These problems are successfully combated by enhancing the steam parameters. Applied material solutions lead to higher plant efficiencies. Protective layers on heat exchanger surfaces which proved to be successful are deposited by APS (atmospheric plasma spraying).

VGB I&C Standards - What does this Mean?

Joachim von Graeve

For several decades the VGB committees have had a great impact on the appearance of control technology in German power plants by implementing standards. The global development is giving rise to questions about the future tasks. Since 2002 a project team of the VGB I&C working group has started to work on writing down the knowledge developing a new collection of standards that enables the members to open up to the market without giving up what they relied on. This article focuses on structure and content of these standards and shows how they can be used between the different demands of market, reliability and continuity.

New Process of Fly Ash for Use in Concrete Exhibiting High Strength and Stable Air Void System

Ernst Pagger, Gernot Krammer

Fly ash from combustion units is increasingly utilised in concrete production partly substituting cement. Besides numerous advantages fly ash has the disadvantage that the concrete's strength builds up retarded that deteriorates the air void system that in turn is decisive for the freeze-thaw resistance. The simultaneous mechanical and chemical fly ash treatment represents a compact process where the features of fly ash can be improved towards a higher early strength and better freeze-thaw resistance (manifested by a suitable air void system) when used in concrete.

HMI Solutions from the Operators's Point of View

Horst-Günther Stürenburg, Frank Neuwirth

Today nearly all power plants are equipped or updated with digital control and screen-based monitoring systems. The HMI has to be designed in such a way that a reliable, environmentally friendly and economical operation can be ensured. Operators of modern HMI systems need clearly arranged mimics and user-friendly operation windows. Only a dialogue between manufacturer and operator will lead to a reasonable solution in construction and utilisation of modern HMI systems.