izsAt rf-ir r.^jeey^v , - v ^ Conference Proceedings DAr46oVTTo /wrr T% Hf^unCTW " ► ‘-•o' .. e k*s#-> "v-1-^ •■■>•"'' •<£>'", ■ DISTRIBUTION OF THIS DOCUMENT IS UNLIMF» N H O S __ s Trace Element Mass Balance for Cadmium at MKS3 Analysis Materials BOTTOM ASM FLY ASH RESIDUAL PRODUCT Process Technology Water Treatment DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 1 Combustion and Flue Gas Cleaning Lecture 1 Flue Gas Cleaning Chemistry Pages 1.1-1.28 Heinz Gutberlet VESA Kraftwerke Ruhr AG, Germany Lecture 2 Converting SDAP into Gypsum Rages 2.1-2.12 in a Wet Limestone Scrubber Folmer Fogh Faelleskemikerne, ELSAMPROJEKT A/S, DK Lecture 3 Combustion Chemistry Pages 3.1-3.46 - Activities in the CHEC Research Programme Kim Dam-Johansen Department of Chemical Engineering Technical University of Denmark, DK Jan E. Johnsson, Peter Glarborg, Flemming Frandsen, Anker Jensen and Martin 0stberg Department of Chemical Engineering Technical University of Denmark, DK Lecture 4 Biofuel Properties and Combustion Experiences Pages 4.1-4.25 Bo Sander , Faelleskemikerne, ELSAMPROJEKT A/S, DK Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 4 Chemical Monitoring and Control Lecture 13 Methods Used by ELSAM for Monitoring Pages 13.1-13.19 Precision and Accuracy of Analytical Results Jan Hinnerskov Jensen Faelleskemikeme Sonderjyl lands Hojspaendingsvaerk An/S, DK Lecture 14 On-line Ion Chromatography at Page 14.1 Ringhals Nuclear Power Plant Staffan Reden Vattenfall, Sweden Rickard Halldin, Vattenfall, Sweden Lecture 15 Experiences with Electrochemical Analysis Pages 15.1-15.20 of Copper at the ppb-level in Saline Cooling Water and in the Water/Steam Cycle Karsten Thomsen Faelleskemikeme, I/S Nordjyllandsvaerket, DK Lecture 16 How Tests of Lubricating and Transformer Oils Pages 16.1-16.17 Became Part of Power Plant Chemisty in Denmark Hans Moller ' Faelleskemikerne, I/S Nordjyl landsvaerket, DK Conclusion of the Conference Lecture 17 Vision 2021: The Utilities Future Pages 17.1-17.22 J. van Liere KEMA, The Netherlands Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 1 Combustion and Flue Gas Cleaning Lecture 1 Flue Gas Cleaning Chemistry Pages 1.1-1.28 Heinz Gutberlet VEBA Kraftwerke Ruhr AG, Germany Lecture 2 Converting SDAP into Gypsum Pages 2.1-2.12 in a Wet Limestone Scrubber Folmer Fogh Faelleskemikerne, ELSAMPROJEKT A/S, DK Lecture 3 Combustion Chemistry Pages 3.1-3.46 - Activities in the CHEC Research Programme Kim Dam-Johansen Department of Chemical Engineering Technical University of Denmark, DK Jan E. Johnsson, Peter Glarborg, Flemming Frandsen, Anker Jensen and Martin 0stberg Department of Chemical Engineering Technical University of Denmark, DK Lecture 4 Biofuel Properties and Combustion Experiences Pages 4.1-4.25 Bo Sander , Faelleskemikerne, ELSAMPROJEKT A/S, DK Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 2 Materials and Corrosion Lecture 5 Degradation Mechanisms of Organic Rubber Pages 5.1-5.23 and Glass Flake/Vinyl Ester Linings in Flue Gas Desulphurization Plants Rudolf Weber Allianz-Centre for Technology GmbH, Germany Lecture 6 Lifetime Evaluation of Superheater Tubes Pages 6.1-6.23 Exposed to Steam Oxidation, High Temperature Corrosion and Creep Niels Henriksen Faelleskemikerne, ELSAMPROJEKT A/S, DK Ole Hede Larsen and Rudolph Blum Faelleskemikerne, I/S Fynsvaerket, DK Lecture 7 Ash Deposition and High Temperature Corrosion Pages 7.1-7.18 at Combustion of Aggressive Fuels Ole Hede Larsen Faelleskemikerne, I/S Fynsvaerket, DK Niels Henriksen Faelleskemikerne, ELSAMPROJEKT A/S, DK i Lecture 8 Coal-Fired Power Plants Pages 8.1-8.25 and the Causes of High Temperature Corrosion John Oakey British Coal Corp., Coal Technology Dev. Division United Kingdom Nigel J. Simms, British Coal Corp., Coal Tech. Dev. Division, UK Andrew B. Tomkings, ERA Technology Ltd., UK Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 3 Water/Steam Cycle Chemistry Lecture 9 Development Tendencies in Cycle Chemistry Pages 9.1-9.10 of Fossil Fired Power Plants Karol Daucik Faelleskemikerne, I/S Skaerbaekvaerket, DK Lecture 10 Local Environmental Conditions and the Pages 10.1-10.17 Stability of Protective Layers on Steel Surfaces Albert Bursik, Germany Jergen Peter Jensen Department of Chemical Engineering Technical University of Denmark, DK Lecture 11 Chemical and Mechanical Control Pages 11.1-11.17 of Corrosion Product Transport i Ole Hede Larsen Faelleskemikerne, I/S Fynsvaerket, DK Rudolph Blum Faelleskemikerne, I/S Fynsvaerket, DK Karol Daucik Faelleskemikerne, I/S Skaerbaekvaerket, DK Lecture 12 Developing the Optimum Boiler Water Pages 12.1-12.18 and Feedwater Treatment for Fossil Plants Barry Dooley Electric Power Research Institute, USA Contents Conference Proceedings Power Plant Chemical Technology 1996 Session 4 Chemical Monitoring and Control Lecture 13 Methods Used by ELS AM for Monitoring Pages 13.1-13.19 Precision and Accuracy of Analytical Results Jan Hinnerskov Jensen Faelleskemikerne Sonderjyllands Hojspaendingsvaerk An/S, DK Lecture 14 On-line Ion Chromatography at Page 14.1 Ringhals Nuclear Power Plant Staffan Reden Vattenfall, Sweden Rickard Halldin, Vattenfall, Sweden Lecture 15 Experiences with Electrochemical Analysis Pages 15.1-15.20 of Copper at the ppb-level in Saline Cooling Water and in the Water/Steam Cycle Karsten Thomsen Faelleskemikerne, I/S Nordjyllandsvaerket, DK Lecture 16 How Tests of Lubricating and Transformer Oils Pages 16.1-16.17 Became Part of Power Plant Chemisty in Denmark Hans Moller ’ Faslleskemikerne, I/S Nordjyllandsvaerket, DK Conclusion of the Conference Lecture 17 Vision 2021: The Utilities Future Pages 17.1-17.22 J. van Liere KEMA, The Netherlands Dr. Heinz Gutberlet VESA Kraftwerke Ruhr AG P.O. Box 10 01 25 45801 Gelsenkirchen Germany Flue Gas Cleaning Chemistry 1. Introduction The introduction of modem flue gas cleaning technology into fossil-fuelled power stations has repeatedly confronted the power station chemists with new and interesting problems over the last 15-20 years. Both flue gas desulphurization by lime washing and catalytic removal of nitrogen oxides are based on simple basic chemical reactions (Figure 1): ♦ the reaction of limestone, water and atmospheric oxygen with the pollutant sulphur dioxide to form calcium sulphate, and ♦ the reduction of nitrogen oxides by means of ammonia to give nitrogen and water. Owing to their simple basic principles, i.e. the use of readily available starting materials, the production of safe, useful end products and, last but not least, the possibility of implementing all this on an industrial scale by means of efficient process engineering, limestone desulphurization and catalytic removal of nitrogen oxides dominate the world market and, little by little, are becoming still more widespread. It could be asked what, given this increasingly mature technology, is still to be done by power station chemists and what expert groups still have to consider today. 1.1 2) •S0 5 ~ +HS0 3" SO4 2-+ ■ S0 4-+ H+ •SO 4- +HSO 3~ -> SO 42-+ ■ S0 3-+ H+ In both reaction mechanisms, both sulphate and sulphite free radicals are formed, in accordance with the following overall equation: ■S0 5 - + 2HS0 3 - 2SO 42- + S0 3- + 2H+ If, owing to a complete reaction, sulphite or hydrogensulphite ions are no longer available to maintain the chain reaction, the peroxomonosulphate free radicals react with other oxidizable substances, for example heavy-metal ions, such as Mn^ + or Fe2+, and consequently regenerate the M^+ ions necessary for chain initiation. The peroxomonosulphate also acts as oxidant. •so5 -+M2+ + H+ -> hso5 -+M3+ HS0 5 -+M2+ +H+-+ S0 4-+M3++H20 SO 4- + M2+ S 042~+M3+ Since a peroxosulphate free radical causes the formation of three M^+ ions in this reaction chain, this is referred to as sulphite-induced autoxidation of the metal ions. In desulphurization systems, this is evident from precipitation of manganese dioxide (MnC> 2) and a darkening of the calcium sulphate, since Mn^ + ions tend towards dis­ proportionation. 2Mn3+ + 2H20 Mn02 4 +Mn2+ + 4H+ The peroxosulphate (free radical) is such a strong oxidant that, once the readily oxidizable species have been consumed, even substances which are normally difficult to oxidize are attacked. Sulphite-induced oxidation can consequently also result in the formation of free halogens. However, the prerequisite is that the steady-state concentration of sulphite moves towards zero. However, the oxidant is constantly re-formed from the absorbed SO2. When excess sulphite is no longer available as reducing agent, the strongly oxidizing species remain in solution. In practice, this can be measured, for example, through a high redox potential of the absorber suspension of from -400 to -500 mV. In addition, chain 1.4 termination reactions between the free radicals cause the formation of the by-products dithionate and peroxodisulphate, which can be found in the absorber suspension. •SOs~ + ' * SO$~ •SO 3- + • S0 5 ~ -> S 2O82' •SO 4- + • SO 4- -> &20$~ •SO 5 - + • SO f s2°82' + O2 Chemical analysis of the absorber suspension for dithionate and peroxodisulphate gives - even in unfamiliar systems - a clear indication of the operating conditions of desulphurization systems (Fig. 3). The occurrence of peroxodisulphate (the concentration can rise to a few