Archive: O&M

Emissions Control: Layered NOx Reduction on a 500-MW Cyclone-Fired Boiler

Historically, cyclone-fired boilers have been characterized as big emitters of NOx due to the very high temperatures in their primary combustion zone. Uncontrolled levels from 0.8 to 1.9 lb/mmBtu have been typical. The design of cyclone-fired units makes them impossible to retrofit with standard low-NOx burners. Prior to 1997, the conventional wisdom was that cyclone […]

Emissions Control: Cost-Effective Layered Technology for Ultra-Low NOx Control

Layering NOx control technologies can reduce a coal-fired unit’s NOx emissions to levels achievable by selective catalytic reduction alone. Advanced Combustion Technology Inc. (ACT) ( has demonstrated that using several in combination can cut emissions from boilers firing eastern bituminous coal or No. 6 oil to less than 0.15 lb/mmBtu. The following two case studies […]

Monitoring key gases in insulating oil keeps transformers healthy

Large T&D-sized transformers age as quickly as generating assets do. But preventing transformers from failing is difficult because they have no moving parts and are sealed up. Tracking the concentrations of certain gases—the more, the better—that are dissolved in a unit’s insulating oil is a proven way of detecting damage before it causes a costly problem.

SO3’s impacts on plant O&M: Part I

The visible consequences of sulfuric acid aerosol emissions—opaque stack emissions called “blue plumes”—are merely the tip of an iceberg. In sufficient concentration, SO3 also can increase corrosion and fouling of equipment and components downstream of the furnace while decreasing their efficiency and penalizing overall plant heat rate.

Meeting utility industry challenges through innovation

In 2005, Xcel Energy fully implemented its unique Utility Innovations initiative to encourage its IT vendors to work together. One pilot project completed under the UI umbrella confirmed that tighter integration of predictive and analytical systems and data can optimize preventive maintenance intervals, reducing costs and downtime while increasing profits and productivity.

Apply the fundamentals to improve emissions performance

The O&M staff of AES Westover Station wisely took a holistic approach to optimizing combustion within Unit 8’s boiler in order to reduce its NOx emissions while maintaining acceptable levels of carbon-in-ash content. The results of major modifications—centered on the addition of a fan-boosted overfire air system—were a 60% reduction in NOx levels, improved unit reliability, and a project payback period measured in months rather than years. As this project proved, the whole is more than the sum of its parts.

Focus on O&M (October 2006)

Upgrading to digital–twice / Lower-cost turbine monitoring / Pros and cons of remote process control / Nuts about Superbolt

How to conduct a plant performance test

Performance testing after initial start-up has value well beyond the short-term goal of validating equipment guarantees—it’s your only opportunity to establish the baseline performance of the overall plant and many of its major systems. Corporate bean counters may be interested in short-term results, but a good plant engineer understands that a thorough performance test will be useful for many years. Here’s your guide to each facet of a performance test—plus pitfalls to avoid.


Focus on O&M (September 2006)

Level measurement in harsh environment;

Designing insulation for structures;

Shockingly clean boiler