Popcorn Ash “Plugging” Catalyst Replacement Models
Coal-fired power generating stations are increasingly aware of popcorn ash “plugging” their SCR catalysts, and thus, their catalyst lifecycle replacement models as well. Although experts from SCR catalyst manufacturers rarely predict significant plugging of the catalyst face from LPA or popcorn ash in the design stage of a SCR retrofit project, all too often a mid season inspection reveals an unexpected popcorn ash problem and the need to replace catalyst prematurely. Utility project planners report that the catalyst plugging also “plugs” their economic models designed to predict catalyst life cycles and associated replacement costs. “We never built a catalyst plugging scenario potential into our lifecycle model,” reports a utility vice president. “We were forced to replace a tier of catalyst in half its life expectancy at a 33% cost overrun.” Several coal-fired power generators have attempted to address this problem by installing various derivations of woven wire mesh screens upstream of the AIG system to filter out the LPA. At first, they generally report that their SCR catalyst is operating more effectively; however, over time, the high temperature and erosive properties of the LPA tend to erode the screen mesh, often in less than one ozone season. In order to address this problem, Integrated Global Services designed a patent-pending high temperature erosion resistant material that could greatly extend the life of the filtration system. Moreover, given the limitations of woven wire mesh, IGS introduced an advanced perforated plate material and supportive housing elements that, combined, significantly outlast any other available LPA filtration system in the marketplace today. The resultant system, NoNOx Components™, has emerged as the most trusted, premium quality LPA system in the world. With over 50 successful SCR installations in the U.S. and Europe, IGS offers full scale design, modeling, manufacturing, and installation capabilities, and guarantees system longevity and performance with a long term warranty program. As such, SCR system designers and owners can be reassured of their catalyst lifecycle assumptions. NoNOx Components™ represents yet another example of how IGS has increased the reliability of mission critical equipment.