Archive: Coal

SO3’s impacts on plant O&M: Part II

Part I of this three-part series (POWER, October 2006) explored the negative impacts of sulfur trioxide (SO3) on the operation and maintenance of back-end plant equipment. In this issue, we list and quantify the likely and potential benefits of limiting the concentration of SO3 in flue gas to 3 ppm at the entrance to the air heater. Part III—to appear in the April 2007 issue—will describe the characteristics of an optimal SO3 removal technology and present the technical details and operating experience of one patented process that has worked successfully at a half-dozen plants for up to three years.

Finding and fixing cracks in high-temperature headers

The welds on superheater and reheater headers are arguably the most stressed parts of a modern steam plant. For that reason, it’s surprising that they also may be the most under-inspected. Cracks are rare, but they can be repaired if found early. One plant avoided a long forced outage to replace a reheater outlet header by using the correct condition assessments and welding techniques.

To optimize performance, begin at the pulverizers

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 NOx 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.

Global Monitor (January 2007)

DOE walks the clean coal talk / For Swedish nuke, a case of mistaken identity / Siemens completes big CHP plant / E.ON bets big on coal / BP Solar expands Maryland plant / GE scores big turbine deals / PSNH switches from coal to wood / EPRI tests solid-state current limiter / POWER digest

Investment in generation is heavy, but important needs remain

Forecasting the direction of the U.S. electric power industry for 2007, much less the distant future, is like defining a velocity vector; doing so requires a direction and speed to delineate progress. In this special report, POWER’s first stab at prognostication, the editors look at current industry indicators and draw conclusions based on their more than 100 years of experience. To borrow verbatim the title of basketball legend Charles Barkley’s book: I May Be Wrong but I Doubt It.

Coal Plant O&M: Coal Drying Reduces Pulverizer Start-up Costs

If coal leaving a pulverizer isn’t dry, it may plug up the coal pipes leading to the boiler. The coal-drying process in a pulverizer is similar to that used by flash dryers. Certain coals should be preheated to make them more combustible. Generally, preheating is done on higher rank coals — those with a low […]

Speaking of Coal Power: Shedding More Heat Than Light

When Charles Dickens began A Tale of Two Cities with, "It was the best of times, it was the worst of times," he was referring to the French Revolution of the late 18th century. But Dickens’ words apply equally well to the American generation industry of the late 20th century. A decade of overbuilding U.S. […]

Coal Plant O&M: Elemental Analyzer Checks Quality of Delivered Coal in Real Time

When you receive a shipment, you don’t wait weeks to see whether you got what you paid for — do you? J.M. Stuart Generating Station doesn’t, but it used to. Since coming on-line in the early 1970s, the big plant, on the Ohio River near Aberdeen, Ohio, mechanically sampled coal shipments as they reached the […]

PRB Tech Notes: Give Coal Handling the Priority It Deserves

Over the past 17 years — dating back to the 1990 Clean Air Act Amendments and including the introduction of retail competition — coal-fired power plants have become much cleaner and more efficient. Utilities have spent many billions of dollars to install pollution controls for regulatory reasons, and only slightly less to upgrade turbine-generators and […]