Contents Issue 4 (1999)

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Joseph B. Conlin and Donald Vinnicombe

Periodic Oxygen Treatment for Drum Boilers

The application of oxygen treatment in units with drum boilers is subject of many discussions. The ESKLOM research program of this matter and the results of the field application (600 MW unit with drum boiler) are presented. The chosen oxygen treatment variant - a periodic oxygen treatment - has resulted in a significant reduction in the transport of iron oxides eroded/corroded from the feed system to the boiler. On conventional ammonia/hydrazine treatment, the iron concentrations at the economiser inlet were 15 µg/kg and these values were reduced to 5 µg/kg on removal of hydrazine and to less than 1 µg/kg with periodic oxygen injection with 5 - 10 µg/kg of oxygen.

PowerPlant Chemistry 1999, 1(4)

Kevin J. Shields, Barry Dooley, Thomas H. McCloskey, Barry C. Syrett, and John Tsou:

Copper Transport in Fossil Plant Units

Copper transport in fossil plant utility cycles has been a problem area for many years. Review of the state of knowledge regarding copper corrosion, transport and deposit activity reveals a deficient understanding of the science involved. Research activities - planned and needed - to improve the state of knowledge are identified. Utility practices considered applicable to minimization of copper transport are described.

PowerPlant Chemistry 1999, 1(4)

Andrew Howell

Mitigation of Copper Deposition in High Pressure Turbines of Utility Drum Boilers

Extensive deposition of copper on surfaces in the high-pressure section of the turbine at power-generating stations has become a significant industry problem. Original and secondary sources are discussed in detail as well as the respective release of copper. The modes of deposition and the transport pathways to the turbine are described. Particular attention is paid to mitigation or elimination of copper deposition and to removal of copper deposits from the turbine.

PowerPlant Chemistry 1999, 1(4)

Karol Daucik:

Strategy of ion exchange demineralisation at ELSAM

Several problems with makeup water production at ELSAM power plants in Western Denmark in the seventies and the eighties initiated an extensive investigation. The work resulted in elaboration of a design strategy and rationale for operation and maintenance assuring safe and reliable production of high quality makeup water. This strategy has stood the test of time. Basic principles of this work are summarised in this paper.

PowerPlant Chemistry 1999, 1(4)

Michael A. Sadler and Barry Dooley:

Possible Methods of Reducing the Cost of Condensate Polishing on Fossil Fired Power Stations

This paper explores ways in which the benefits of condensate polishing can be more economically achieved on fossil fired boilers. It is directed at conventional once-through and drum boilers and also at the newer designs of Combined Cycle Heat Recovery Steam Generators (HRSGs). Suggestions for reducing capital costs include the use of off-site contractor regeneration services to eliminate the need to install regeneration equipment on every station and effluent disposal problems. The possibility of the development of smaller, lower cost, service vessels which employ shallow beds of smaller bead size resins is also explored. In particular the merits of the compact radial flow vessel design are discussed, as there is experience of them being used on BWR reactor water clean-up circuits. The variable costs of operating full flow condensate polishing are largely controlled by the circuit pH. It is possible to make savings by operating on partial by-pass or in the ammonium form. There are, however, disadvantages in both of these procedures. Plant design and operating procedures should therefore be explored aimed at making them more acceptable.

PowerPlant Chemistry 1999, 1(4)

Eduard Noks, Anton Olkis, Roland Kleinstück, and Donald A. Johnson

The Use of Ozone as Microbiocide in Cooling Water Treatment - Experiences with an "All-Organic" Program

In the past few years interest in the use of ozone as a microbiocide in cooling water systems has grown. Ozone is an extremely strong oxidizer that might destroy some of the organic chemicals traditionally used in cooling water treatment. This paper describes the interaction of ozone and organic cooling water additives in two industrial cooling systems. The stability of phosphonates in the presence of ozone is subject of deep evaluations. The interest in the use of ozone as a microbiocide in cooling water systems has grown in the past few years. Ozone is an extremely strong oxidizer that might destroy some of the organic chemicals traditionally used in cooling water treatment. This paper describes the interaction of ozone and organic cooling water additives in two industrial cooling systems. The stability of phosphonates in the presence of ozone is subject of deep evaluations.

PowerPlant Chemistry 1999, 1(4)