Large Particle Ash: A Million Dollar Problem?

/EINPresswire.com/ HOLDEN, MA - Large particle ash (LPA) poses a serious threat for coal-fired utilities today. First brought to light with the advent of retrofitted Selective Catalytic Reduction (SCR) systems to address federal NOx regulations, particle ash build-up has become a million dollar problem, one that plant operators can't afford to ignore.

When left unchecked, LPA buildup wreaks havoc within a plant's SCR system, causing gas pass pluggage, sub-par performance, increased emissions, ammonia slip—and outages. One unplanned outage from ash build-up can cost an 800 MW power plant a half-million dollars per day or more. And just a half-pound of LPA per hour - a tiny percentage of the 30,000-80,000 lbs of ash typically produced in that time — can clog up a catalyst in as little as 3 to 6 months. Experts at Alden say there's no clear way to stop large particle ash from forming. But with a three-step approach, plants can protect their performance, permitting status and their bottom line:

Step One: Start with good housekeeping.
Plants can avoid a lot of damage by systematizing their cleaning and inspection processes, including emptying ash hoppers on a routine basis. During planned outages, inspect screens and systems for signs of ash buildup or wear and tear.

Step Two: Understand your problem.
Every plant is different. Modeling with actual ash samples from the plant helps operators determine the type of ash they're dealing with, its aerodynamic density, and how ash particles are moving through the plant - the solid data they need to evaluate effective fixes.

Step Three: Create a systemic change.
Trap ash within the economizer outlet hoppers and prevent it from clogging up the catalyst by making internal geometric changes such as adding "kicker" plates and/or outlet screens. Plants may also troubleshoot the problem by changing fuel sources or adjusting firing conditions. However, these latter options can be costly and may not achieve the desired result.

About Alden
Alden (Alden Research Laboratory, Inc.) is an internationally acclaimed leader in solving flow-related engineering and environmental problems. For more than four decades, the company has provided engineering, field and laboratory technical assessments for the power industry and a transfer of knowledge to regulatory agencies. On its 32-acre campus in Holden, Massachusetts, including more than 150,000 square feet of lab space, Alden provides engineering, physical and computational flow modeling along with environmental, flow meter calibration, and field services. Founded in 1894, Alden is the longest continuously operating hydraulic laboratory in the United States. Learn more at www.aldenlab.com.
Contact: dschowalter@aldenlab.com.