Air Heaters: Neglect at Your Own Risk

摘要

Steam Generating Systems at Electric Utilities are Essentially a Series of Heat Exchangers: condensers, deaerators, feedwater heaters and, of course, boilers and superheaters. Poor performance of even one major heat exchanger can significantly affect unit efficiency. An exchanger whose performance is sometimes overlooked is the air heater, perhaps because it is not as easily or closely monitored as other exchangers. Yet, at coal-fired plants, ash fouling of the air heater can be a major problem. The problem has become worse at many of the coal-fired utilities that have switched to the low-sulfur, but high-mineral, coals from the Powder River Basin. Periodic off-line cleaning can restore heater performance, but what is the best cleaning method? This article outlines some of the most practical techniques.