Analiza pracy rurowych podgrzewaczy powietrza kotła z CWF dużej mocy

The article presents the results of investigation of the operation conditions of tubular-type air heaters of 670 MW CFB boilers. It has been found from the investigation carried out that the presence of sulphuric acid in the flue gas increases the dew-point up to a level as high as 904 80°C, depending on the acid concentration. This phenomenon occurs especially in both lines of the primary air heater, and less intensively in the secondary air lines. These phenomena show the highest intensity in the vicinity of the inlet screen wall, over a section of up to 600 mm. In this region, the air from the steam air heaters has the lowest temperature (in the flue gas zone). The corrosion process is further promoted by the erosive action of ash. The perforation of the tubes causes the discharge of air at a higher compression, which is the cause of disturbance in flue gas flow, a swirl of fly ash, and intensive erosion and corrosion effects over the 75-85% of the tube perimeter.