Fin gaps on the flue gas side become clogged with dust, and heat exchange capacity gradually declines—this is a phenomenon commonly reported by O&M personnel during inspections. In this situation, should mechanical rapping continue to be used, or should compressed air online blowing be adopted instead? Before choosing, it is necessary to first clarify the structural characteristics of the equipment itself.
The HZQ-580 tubular fin heat exchanger adopts a steel tube wound-fin or sleeved-fin structure. The fins and base tubes are fixed by expansion or welding, and the flue gas side channels are relatively open. Compared with bare-tube shell-and-tube solutions, the heat exchange area is increased under the same volume, and the equipment footprint is relatively compact; compared with plate-type solutions, it is more suitable for flue gas working conditions with relatively high dust content, and the cleaning channels after blockage are also more direct. It should be noted that the fin root is a stress concentration location, and repeated mechanical rapping may accelerate root fatigue. This point should be included in the consideration of maintenance methods at the selection stage.
The design pressure, design temperature, and interface specifications of this type of heat exchanger can be customized according to project requirements and should be clearly marked on the nameplate. When O&M personnel check the nameplate, it is recommended to focus on the margin between the design temperature and the actual on-site flue gas temperature, as well as whether the interface flange standard is consistent with the existing pipeline.
Mechanical rapping ash cleaning is suitable for dry dust working conditions. It has a simple structure and requires no air source, but it has a fatigue effect on the fin roots; compressed air online blowing has little impact on production and is suitable as a routine maintenance method, but its disadvantage is that it is limited by air source conditions. The two methods can be used in combination, and the specific frequency is determined according to the on-site ash deposition rate.
