Abstracts - VGB PowerTech Journal 3/2015

Future pathways for today’s technologies: Limits and opportunities

Stefan Nießen

The majority of the feed-in tariffs as determined by the German Energy Feed-in Act (EEG) develop as follows: they decrease as the efficiency of technologies grows. However, there are some exceptions: offshore wind and geothermal energy feed-in tariffs have been rising, while storage technologies are not included at all although they are needed to make up for intermittent renewable generation. Furthermore, nuclear energy is burdened with the fuel tax, a kind of negative feed-in tariff. These technologies seem to be confronted with specific restrictions that yet prevent large-scale development. A thorough analysis of these limitations guides to the way to overcome them.

Le Havre CCS pilot project – A stepping stone in the EDF Group to tackle the CO2 challenge

Francois Giger, Fabrice Chopin and Jean-François Lehougre

As part of an R&D programme aimed at tackling the CO2 challenge, the EDF Group participated in three collaborative projects that were supported by ADEME, the French Environment and Energy Management Agency; the “France Nord” CO2 geological storage project and the PILANSU and C2A2 capture projects. The results obtained in the first project showed that the expected CO2 storage capacities identified did not match by far the expectations. They cast a shade of doubts on previous optimistic evaluations for onshore CO2 storage potential in European saline aquifers. The last two projects, a physical and a chemical CO2 capture process, were successful and involved a test facility built at the EDF Le Havre power plant with an advanced amine process.

New assessment scheme to support decision making with respect to economically non-viable thermal power plant units

Martin Junker, Andreas Willing and Hans-Josef Sandkaul

The changes in the energy industry have altered in some areas the boundary conditions for thermal power plants to such an extent that the continued economic operation of quite a number of block-unit power stations in Europe is becoming increasingly difficult. Particularly in the field of coal- and gas-fired power plants, operators increasingly have to decide between continued operation, decommissioning and economic commercialisation. To support these decision-making processes, RAG Mining Solutions, in collaboration with MH Power Systems Europe, developed an examination system that establishes whether existing block-unit power stations have broad potential for remarketing, or at least sale of the principal functioning technical components on the market.

“Enhanced Platform” – The next generation of highly flexible and efficient Siemens industrial team turbines

Lutz Völker

Over the last 25 years the market for industrial steam turbines has changed. Today, the field of application for industrial steam turbines is extending and focusing on decentralised power generation and process steam conditioning. With the Enhanced Platform concept Siemens finalised these company associations by combining all well proven technical features from the several product lines in one common basis to create customised steam turbine solutions.

First investigations of low load operation of a large steam turbine

Norbert Latk, Michael Syrbe and Uwe Gampe

The requirements concerning flexibility of conventional power plants have being increased significantly over the previous years. The control capabilities of thermal power plants have to be increased with a focus on the reduction of technical minimum load. Different options have been investigated on a 500 MW power plant unit in order to decrease the minimum load below 20 % related to nominal load. The plant unit design consisting of two boilers feeding to one steam turbine as well as the conversion of the auxiliary firing system from oil to pulverised dry lignite at one boiler proved to be of advantage.

Fuel cell power plants for decentralised CHP applications

Martin Ohmer and Katja Mattner

Fuel cells are the most efficient technology to convert chemical energy into electricity and heat and thus they could have a major impact on reducing fuel consumption, CO2 and other emissions (NOx, SOx and particulate matter). Fired with natural or biogas and operated with an efficiency of up to 49 % a significant reduction of fuel costs can be achieved in decentralised applications. Combined heat and power (CHP) configurations add value for a wide range of industrial applications. The exhaust heat of approximately 400 °C can be utilised for heating purposes and the production of steam. Besides, it can be also fed directly to adsorption cooling systems. With more than 110 fuel cell power plants operating worldwide, this technology is a serious alternative to conventional gas turbines or gas engines.

Determination of effectiveness of cooling water treatment programmes

Frank de Vos and Lars Venhuis

The applicability of water treatment programmes for open recirculating cooling water systems and cooling towers is a very complex matter. Many variables need to be taken into account to avoid scaling, fouling and corrosion. DNV GL has worked on the development of a test procedure – according to an ISO standard – in which the situation in a cooling tower can be simulated and compared. Here not only scaling effects and corrosion phenomena can be simulated, but also the effect on the heat transfer of the test tubes. Test plant, method and ISO standard will be presented and discussed.

The still unknown treatment technologies – Degasification and polishing of boiler feedwater with membrane degasifier and electro-deionisation

Daniel Reznicek and Jack Kügler

Membrane degasification and electro-deionisation are less known and common procedures for polishing boiler feedwater than the classical methods. Modern membranes often provide considerable advantage against conventional treatments due to the application of state-of-the-art membranes, innovative control technology and in-depth consideration of various possibilities of feedwater treatment as well as modular design, operation with zero chemicals and small space requirements. In practice, both the procedures are applied in most various combinations.

An electro-deionisation device for continuous measurement of the conductivity after cation exchanger

Martin Aicher and Heini Maurer

Measurement of electrical conductivity downstream of cation exchange has become the most commonly used analytical method in power plants with steam generators. The simple measuring principle is highly sensitive and reliable. With the advent of reliable electro-deionisation devices (EDI) it seemed possible to substitute conventional cation exchange resin-filled columns by an EDI arrangement. The paper describes such a dedicated device and practical evaluation over several weeks in comparison to a conventional instrument in the secondary circuit of a PWR with high pH. Analytical results are shown, advantages and limitations are discussed.

Colonisation of cooling water systems with mussels

Michael Bolz, Andreas Speck and Micael Jürgensen

In September 2013 an increasing number of mussels growing in the open cooling water systems of the Philippsburg nuclear power plant was observed. It was detected that Dreissena rostriformis bugensis (Quagga) is spreading more and more and replaces very quickly its close relative D. polymorpha.
The paper describes the current knowledge about Quagga mussel. The concrete structures of the cooling systems are mainly affected. It is tried to correlate the density of mussels at the walls to the amount of sediments found during annual inspections. After evaluating different approaches to control the situation, regular mechanical cleaning is preferred in comparison to thermal or chemical treatment of the cooling water.

Firing design for the hard coal-fired steam generator RDK 8 – Concept and first operating results

Hellmuth Brüggemann, Reinhard Gollnick, Michael Kübel and Michael Eckert

Coal-fired power plants continue to play an important role in European energy supply. The new Karlsruhe RDK 8 power plant, fired with hard coal from worldwide sources, has an electrical output of 912 MWel. The overall plant efficiency is above 46 %, and the additional combined district heat production (over 200 MWth) results in up to 58 % of fuel utilisation. The specific CO2 emissions are far below the European and global average. The paper describes the boiler concept of RDK-8 focusing on the firing system. First operating results are also presented.

BLAVIM: A new measuring method to detect blade vibrations of the last LP row of steam turbo sets with installed shaft vibrations sensors

Dietmar Bloemers, Clemens Bueren and Andrés Zilly

With BLAVIM the signals of the eddy current shaft vibration sensors can be continuously monitored for changing blade vibration contents. This new type of monitoring is an inexpensive and easy to setup alternative to other more complex measurement methods. Firstly blade vibration measurement systems will be presented. Then the BLAVIM measuring and analysis system will be explained. On the basis of an example, the eigenfrequencies of the blades will be determined. After the identification of the relevant modes by qualified analysis of run-ups and coast-downs, blade vibrations can be monitored. Several application examples will be presented demonstrating the capabilities of the system.