O&M

The challenge for suppliers of aftermarket turbine blades is that their starting point is an existing blade and nothing else. There are no CAD models, drawings, measurements, tolerances, or inspection data associated with it. However, thanks to the latest in computer tools, a blade now can be digitally recreated to exact specifications and built using the latest design and manufacturing practices. Here’s an inside look at how turbine blades are captured, reconstructed, inspected, and remade to be better than the originals.

The critical subset / Aging workforce challenges / Tighter tolerances in retrofits / Writing sensible start-up and shutdown procedures

The term "water hammer" encompasses a handful of hydraulic and thermohydraulic mechanisms. They include water hammer in steam and water piping, water piston, water induction, flash condensation and evaporation, and shock waves generated by transonic flow. All can lead to failures of steam and water cycle components and put plant operators and workers at risk. Proper design and O&M practices can keep water hammer and similar phenomena under control.

A century ago, boiler explosions were an all-too-familiar event. But with the universal adoption of the ASME Boiler and Pressure Vessel Codes in 1914, explosions caused by poor design or manufacturing became relics of history. Electrical classification codes had the same effect on safety. This article explains how designers and operators practically apply those standards. Code details and samples of area classification drawings for a gas turbine plant are included in an online supplement (see end of story).

Carbon capture and sequestration (CCS) have elbowed their way into the nation’s lexicon with the rise in concern over climate change. But few of the journalists who are hyping global warming have taken the trouble to learn the ins and outs of producing affordable electricity from coal. Citizens of the industrialized world now wring their […]

As gencos seek to improve plant reliability and availability, many are turning to on-line condition monitoring for help. Huge advances in the capabilities of on-line diagnostics have occurred over the past five years. By using this technology, plant personnel can spot early warning signs of impending equipment failure and take action to correct the underlying […]

Dominion Generation (DG) has installed selective catalytic reduction (SCR) systems on many of the large coal-fired generating units it operates. The catalyst used has an SO2 to SO3 oxidation rate of about 1%, which roughly doubles the SO3 concentration at the outlet of the boiler economizers. The magnitude of the increase was proportional to the […]

Flyash and condensed sulfur trioxide (SO3) are the major components of flue gas that contribute to the opacity of a coal plant’s stack emissions (stack opacity). Estimates are that 75% to 85% of bituminous coal-fired plants with selective catalytic reduction (SCR) and/or wet flue gas desulfurization (FGD) systems are likely to produce enough SO3 vapor […]

The compliance clock is ticking / First-class maintenance in a developing country / Bypass losses squander big bucks / Revised operating procedures

A systematic, performance-driven maintenance program for optimizing combustion can achieve great results. The challenge for an O&M staff is deciding which proven strategy and tactics for reducing NO_x and improving plant reliability to adapt and implement. The structured approach presented here has proven its worth at several plants that have wrestled with problems similar to yours.