Graphite-Metal Bearings Tackle High-Temperature Job

摘要

The inlet-air section of a utility boiler is a harsh environment for the dampers that control the flow of preheated air into the combustors. Over time, the hot air dries out the lubricant in the metal bearings, or roller elements, that control the dampers' movement, causing the dampers to seize. This was a problem at the Sioux Power Plant of Ameren UE near St. Louis, Mo. The plant has two 535 MW, coal-fired units, each of which has 10 cyclone burners. There are two dampers on each burner—a control damper and a shutoff damper—for a total of 40 secondary air dampers. "On average, we had a bearing problem about every two months," says James Riegerix, the plant's general supervisor.