Abstracts - VGB PowerTech Journal 4/2005

Current New Projects and Further Developments in Coal-fired Power Plant Technology

M. Kehr, R. Elsen and J. Ewers

In Germany and Europe a considerable demand is emerging for new power plants to replace old stations until 2030. The phase-out of nuclear power agreed upon with the federal government will additionally aggravate the situation in the second decade of this century. The planned projects of RWE Power AG are being presented, and the further development of coal-fired power plant engineering is outlined. Here the pre-drying of lignite is explained as well as the future increase of steam parameters with the related material developments.

Hydro-power in a Competitive Market

H. Schröfelbauer

While energy demand continues to rise, European hydro-power is faced with ever more stringent legal provisions and environmental targets. At the same time, the transition from a monopoly situation to a liberalised electricity market has resulted in a shift in emphasis from macro-economic considerations to a business-management approach to hydro-power as the classic renewable energy source. Hence, for market operators hoping to position themselves favourably through the offer of new products, such as control and balancing energy, it is essential to recognise emerging technology and energy trends at an early point in time. However, fair competition requires a stable legal framework.

Stocktaking and Classification of the Different CO2 Reduction Technologies

J. Ewers and W. Renzenbrink

As reflected by current forecasts, global energy demand for power generation will more than double by 2020. Fossil energy sources will even report a disproportionately high increase. In this conflict of goals, technologies based on fossil energy sources and their further development are the decisive key. This article describes a strategy for medium- and long-term CO2 reduction in power generation.

Co-combustion – The Power Producer's Point of View

R. Hassa and H. Breuer

Co-combustion of alternative fuels at lignite-fired power plants was introduced as a new business line in 1999 and has been expanded gradually in the four lignite-fired power plants of Vattenfall Europe. Heat-recovery incineration of high-calorific-value waste fraction by co-combustion at the highly efficient power plants is an ecologically meaningful contribution to environmentally compatible waste disposal. At the same time, this fuel substitution contributes to reducing the company’s generating costs. The comprehensive preparation up to the erection of a co-combustion plant and the permit for continuous operation are discussed.

Modern Coal Storage Systems, Prepared for Future Environmental Protection Demands, Efficient and Flexible in Operation

H. Basener, M. Laakkonen and J. Ruijgrok

The enclosed coal storage system of the Tiefstack thermal power plant of HEW in Hamburg and the underground coal storage system of the Salmisaari power plant of Helsinki Energy in Helsinki and their operational and economical benefits are the topics of this article. The realisation of the storage systems indeed solved important environmental issues but, contrary to the general opinion, above all the choice for the Eurosilo system has been operationally and economically driven. Significant cost savings in operation, such as utilising dynamic blending, cuts back the pay back period.

Using Mobile Measuring Technology for Process Optimisation in Chinese Coal-Fired Power Plants

T. Hufmann, H. Rall, and J. Moczadlo

The Federal Republic of Germany supports a German-Chinese development project with the objective of efficiency increase and emission reduction in Chinese coal-fired power plants. Content of the co-operation project is a vast transfer of technology and know-how by the delivery of altogether 16 measuring vehicles to 11 Chinese Research Institutes and the associated training of Chinese experts as well as the constitution of an economic based energy service sector for the reformed Chinese energy market.

Online Measurement of Residual Carbon

P. Buck

About 1.5 million units of hard coal are burnt annually by the 760 MW hard-coal firing unit at the Heilbronn thermal power station. Approximately 120,000 tons of fly ash and 50,000 tons of gypsum are produced as by-product. Both products are used by the cement industry if the quality criteria are met. In addition, sludge and petroleum coke are used as fuels. At the end of 2001, two online measuring devices by Promecon were acquired with the aim of relieving the shift personnel from time-consuming measurements. The measuring devices use microwave technology and have been installed in the fly ash collecting container.

C-online Measuring Device in Gersteinwerk Power Plant of RWE Power AG

K. Waßmann

The increasing pressure on the electricity market forces utilities to continuously check their possibilities to cut costs in order to produce electricity at competitive prices.
One possibility is to offer certified fly ash, i.e. the residue from coal combustion, removed off the flue gas, to the building industry. This, however, is connected with some requirements like recording the residual carbon content in fly ash.
Since July 2001 RWE has been operating successfully a carbon-online measuring device of DBT Automation.

Studies to Assess The Suitability of High-temperature Filter Materials for Use in Power Plants

J. Angermann and B. Meyer

The application of the pressurised fluidised bed technology is an option to use the thermodynamic advantageous CC-power plant process for solid fuels. In this context several system concepts of the second generation pressurised fluidised bed technology were developed. Filter materials for the gas cleaning are necessary, which are resistant in oxidising or reducing atmosphere and at high temperatures, depending on the power plant design. Based on this fact, a research project was realized at the Technical University Bergakademie Freiberg which was supported by the BMWi-promoted joint research project “Hot gas cleaning”. The results are presented.

CO₂ Removal in Power Stations by Sorption-integrated Shift Reaction – Principles and Materials

C. Gauer and W. Heschel

Regarding coal-fired power stations gasification of the feedstock and CO₂ capture before combustion is predicted to be one of the most efficient concepts. In the required shift reaction CO is converted to CO₂ and H₂. If CO₂ is removed in situ by chemical absorption with solids the equilibrium of the shift reaction is replaced by the more favourable one of the so-called sorption-integrated shift reaction. Li4SiO4 is a particularly promising candidate material which shows increased reactivity for CO₂ absorption and desorption as well as catalytic activity for CO oxidation if doped with iron. Assuming sorption-integrated CO shift would be employed for CO₂ removal, e.g. in a future IGCC process Fe-doped Li4SiO4 might be an absorbent of choice.

Fludised Bed Combustion Technology in Poland

J. Kurp, H. Tymowski and K. Szynol

When projecting modern power plants not only efficiency is in the focus but also environmental protection aspects. In this connection circulating fluidised bed combustion gained in importance since it is an interesting alternative to common firing processes. In the last ten years fluidised bed combustion processes have been developed to market maturity.

Combustion Behaviour of Refuse Derived Fuels - Development of a Characterisation Method

Th. Marzi and K. Keldenich

Renewable primary products and refuse derived fuels will gain in importance in combustion technology. While the behaviour of fossil fuels like coal, crude oil and gas is well-known, there are still many uncertainties about the behaviour of refuse derived fuels in combustion plants. Conventional methods for the characterisation of fuels are not sufficient for an estimation, since there is no information about the release of volatile compounds at different temperatures and the calorific value of the volatile compounds.
This article describes the development of a new method for the characterisation and classification of different fuels. The results can be used for the optimisation of plant engineering and construction as well as for line operation. Additionally, the results can use for the selection and the production of fuels.

Electrochemical Deionisation for Chemicals-free Treatment of Boiler Feedwater

G. Sigl, R. Schaber, J. Sambach and S. Hirschmann

The combination of the reverse osmosis (RO) and electrochemical deionisation processes allows feedwater to be generated with a minimum of chemicals. The paper describes the principles, technology and design of such an RO-EDI system. Different from the conventional demineralisation (demin) plant, the RO-EDI technology does not require chemicals such as sodium hydroxide solution and hydrochloric acid. These advantages open up opportunities for increased use of the RO-EDI technology for feedwater treatment in industry and in power stations.