New application guides from ABB to boost power plant efficiency

The vast quantities of water used to produce steam in power generation applications mean that achieving well-balanced water chemistry is vital. To do so, optimum positioning of analytical instruments at key points throughout the water and steam cycle and water treatment plant at modern power stations is essential. This will in turn significantly improve plant efficiency and cost effectiveness.

Our new series of application guides, produced as part of the launch of the latest products in our Navigator analyser range, reveal how operators can optimise boiler chemistry and steam quality in power generation applications through the control of the parameters affecting steam generation efficiency.

Titled ‘Optimising power plant performance through silica monitoring’, the first of our four guides in the series, each of which focuses on a different parameter, reveals how careful monitoring of boiler conditions is essential to prevent corrosion and build-up of scale, protect the plant and ensure it remains in good working order.

Silica is a major culprit behind the build-up of hard and dense scale inside the boilers and turbines of power generation plants. Silica forms a dense porcelain-like scaling that cannot be removed even with acid. Silica scaling also has a very low thermal conductivity which means that even a 0.5mm build-up can reduce thermal transfer by 28%, reducing efficiency, leading to hot spots and eventual rupturing, resulting in plant failure.

However, the guide also reveals how our Navigator 600 Silica analyser, which helps cut the costs and maintenance associated with silica, can effectively control build-up through effective monitoring at multiple points around the steam generation and distribution cycle.

The second of the four guides in the series, ‘Improving dissolved oxygen control through online monitoring’, outlines how accurate measurement of dissolved oxygen is essential for efficient, cost effective, operation of boiler plant with minimum downtime.

The presence of even small quantities of dissolved oxygen in boiler water can severely impair a boiler’s operation, causing corrosion of its vital components and significantly reducing its working life. As such, the guide contains an easy-to-follow illustration, highlighting how an effective monitoring system should measure dissolved oxygen with an analyser at key points prior to the boiler.

Techniques for further reducing dissolved oxygen levels are covered in the guide, ‘Reducing dissolved oxygen through hydrazine dosing’. Even after deaeration, it is still necessary to administer some form of post treatment in order to achieve further reductions in dissolved oxygen levels.

The guide details how this can be done successfully by dosing the boiler feedwater with hydrazine. As a powerful reducing agent, hydrazine reduces oxygen to form nitrogen and water, which can help to further reduce dissolved oxygen levels to concentrations. Therefore, continuous monitoring of hydrazine throughout the feedwater loop can help to achieve the most effective ratio of hydrazine to dissolved oxygen.

The final guide in the series, ‘Controlling sodium concentrations through on-line analysis’, explains how the impact of sodium on power plant performance, one of the most important parameters to measure in power plant applications, can be minimised through accurate and reliable sodium monitoring.

If you would like to get hold of a copy of any of our new application guides, simply email: moreinstrumentation@gb.abb.com, providing details of which in the series are of interest.

Alternatively, for more information on our Navigator range of water analysers, check out the following video which details how the range can help optimise plant efficiency: http://www.youtube.com/watch?v=U92gwQS5HfU

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