Contents Issue 3 (2002)

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English Abstracts

Howard Ocken and Sean Bushart

Radiation Exposure Management Update December 2001

Nuclear utilities are obligated to implement technology to protect plant personnel from the adverse effects of ionizing radiation. EPRI's Radiation Exposure Management Program supports two main activities to address this issue: [i] radiation control technology reduces shutdown radiation fields and [ii] radiation protection technology optimizes worker safety and productivity. This paper summarizes recent EPRI successes, which have helped U.S. nuclear utilities reach historic low levels of collective exposure.
PowerPlant Chemistry 2002, 4 (3)

Ian A. McLure, Andrei Yu. Petrov, Duncan H. Gordon, Malcolm Ball, and R. Barry Dooley

Interfacial Behavior at Above-ambient Temperatures of Ionic and Non-Ionic Aqueous Solutions Important in Boiler Water Chemical Conditioning

The reliability and efficiency losses in steam turbines have been one of the major problems faced by the utility industry worldwide. The size of droplets in the last low pressure stages of the turbine is one of the most important factors affecting these losses. One method of controlling the droplet size might be by changing the surface tension in the turbine environment.

The paper presents results of the EPRI sponsored research on the surface tension of various substances which might be present in or added to the power plant cycle as conditioning chemicals (inorganic salts, ammonium and amine compounds) and discusses whether they can exert a significant effect on surface tension in amounts typical for power plant operation.
PowerPlant Chemistry 2002, 4 (3)

Frank Gabrielli, Stephen Goodstine, and Thomas Mastronarde

Cold-End Corrosion in HRSGs

Many of the processes for increasing the efficiency of combined cycle plants can result in lower flue gas temperatures exiting the heat recovery steam generators and/or increased flue gas moisture content. These conditions can as a consequence increase the potential for corrosion of the low temperature gas-path components. The attack of these surfaces is generally referred to as cold-end corrosion. There are various aspects and components of cold-end corrosion, of which the most significant is dewpoint corrosion. The paper discusses these corrosion mechanisms of major significance to heat recovery steam generators as well as present results from field and laboratory tests programs.
PowerPlant Chemistry 2002, 4 (3)

Pierre J. Ploumen

Avoiding HRSG-Tube Failures

Based on long-standing experience with the analysis of boiler tube failures, KEMA has expertise in the aspects that are crucial to avoiding tube failures. In particular, KEMA has gathered experience with heat recovery steam generator tubes over a period of 25 years. The crucial aspects concern the design of the boiler, the choice of design values, heat flux, and the water treatment.

An overview of failures in heat recovery steam generators in the Netherlands is presented, including an explanation of the cause of the failure. Design aspects of heat recovery steam generators are also discussed, especially the necessity of achieving an equal flue gas flow distribution and water distribution.
Furthermore, the influence of an unequal flow distribution on the tubes in a horizontal LP evaporator, resulting in increased heat flux, changes in steam quality and void fractions are discussed. The results are based on two-phase flow calculations of an LP evaporator with its own computer programs.
Guidelines for water treatment are given to avoid tube failures.
PowerPlant Chemistry 2002, 4 (3)

Ladislav Bursik

Seminar "Combined Cycles and Heat Recovery Steam Generators" Was a Big Success

The PowerPlant Chemistry Seminar "Combined Cycles and Heat Recovery Steam Generators – Development, Boiler Tube Failures, Chemistry, and Monitoring" took place on February 6–7, 2002, in the Stadthalle Hockenheim (Germany). The seminar participants came from thirteen, the lecturers from three countries. The paper reports on the seminar presentations and discussions.
PowerPlant Chemistry 2002, 4 (3)

Albert Bursik

Boiler Tube Failures in Industrial Drum-Type Steam Generators - Boiler Water Treatment

Boiler tube failures in industrial drum-type steam generators are very frequent. The root causes of the most serious boiler tube failure mechanisms occurring in industrial boilers are related to plant cycle chemistry. Unfortunately, the internationally accepted fossil cycle chemistry guidelines drawn up and published by VGB and EPRI do not reflect conditions typical in industrial steam generating installations.

Part 1 of this paper dealt with the major differences between steam generation in utility boilers and in industrial steam boilers and other steam generating apparatus (e.g., differences in design, material selection, and cycle contaminants) and treated some site-specific issues influencing cycle chemistry. The applicability of VGB or EPRI feedwater guidelines was evaluated and discussed. This paper (Part 2 of a planned publication) deals with the applicability of internationally accepted boiler water treatments and with their influence on occurrence of boiler tube failures.
PowerPlant Chemistry 2002, 4 (3)

Harry J. G. Polman und Henk A. Jenner

Pulse-Chlorination®, das beste Verfahren zur Vermeidung von Makrofouling bei Chlorung

1998 entwickelte KEMA ein neues Chlorungsverfahren, das als Pulse-Chlorination® bekannt ist. Das Verfahren ermöglicht eine optimale Wasserbehandlung zur Vermeidung von Makrofouling bei einem minimalen Chloreinsatz. Diese Technologie basiert auf der Tatsache, dass Muscheln und Klaffmuscheln, nachdem sie Chlor ausgesetzt wurden, im Allgemeinen eine Erholungsperiode benötigen, bevor sie sich wieder öffnen und zu filtrieren beginnen. Das Verfahren nutzt diese Erholungsphase, indem es kurze aufeinanderfolgende Chlorungsintervalle mit den Perioden ohne Chlorung abwechselt. Die zwischen 1998 und 2001 durchgeführten Tests führten im Vergleich zu Fahrweisen in den vergangenen Jahren zu Einsparungen im jährlichen Chloreinsatz von bis zu 50%. Betriebsergebnisse nach einem Jahr des Einsatzes der Pulse-Chlorination® zeigen eine bessere Beherrschung des Makrofoulings sowie eine verbesserte Leistung des Kühlwassersystems. Dies wiederum erlaubt längere Zeitabstände zwischen geplanten Stillständen und dadurch eine Herabsetzung der Betriebskosten. Zusätzliche Vorteile gibt es für Kraftwerke, die Elektrolyse-Chlorungsanlagen zur Herstellung von Hypochlorit verwenden. Da Pulse-Chlorination® die Hypochloritdosierung um bis zu 50% reduziert, wird nur ein Teil der installierten Elektrolyse-Leistung benötigt, so dass die sich nicht im Einsatz befindlichen Anlagenteile zwischenzeitlich gewartet werden können. Da weniger Hypochlorit dosiert wird, fallen auch weniger Nebenprodukte der Chlorung an und die Umwelt wird weniger belastet.
PowerPlant Chemistry 2002, 4 (3)

Karol Daucik

Konservierungspraxis bei ELSAM

Dieser Beitrag behandelt Konservierungsverfahren für große Kraftwerksblöcke. Da fast alle großen Blöcke bei ELSAM Blöcke mit Zwangdurchlaufkesseln sind, werden nur solche Anlagen in Betracht gezogen.
PowerPlant Chemistry 2002, 4 (3)

Ladislav Bursik

Seminar "Combined Cycles and Heat Recovery Steam Generators" war ein großer Erfolg

Das PowerPlant Chemistry-Seminar "Combined Cycles and Heat Recovery Steam Generators – Development, Boiler Tube Failures, Chemistry, and Monitoring" ("Kombianlagen und Abhitzekessel – Entwicklung, Kesselrohrschäden, Chemie und Überwachung") fand am 6. und 7. Februar diesen Jahres in der Hockenheimer Stadthalle statt. Die Seminarteilnehmer kamen aus dreizehn, die Referenten aus drei Ländern. Der Beitrag berichtet über die Seminarvoträge und -diskussionen.
PowerPlant Chemistry 2002, 4 (3)