Summary

The steam generators at RWE Rheinbraun's Weisweiler power station are intended for baseload operation, with fuel supplied from the Inden open-pit mine. Flue gas excess pressure arising from possible hot standby operation was therefore not taken into account in the design of cleaning systems for the steam generator heating surfaces.
At Weisweiler power station there are six units, with a total of nine boilers. Water blowers were originally installed for cleaning the furnaces of the steam generators. However for the 1900t/h steam generators of units G and H, it was decided to add water cannons.

In 1992 a test water cannon was installed and numerous measurements were performed to determine wall temperature loading during cleaning by the cannons. In the first step four water cannons ere installed in each boiler of units G and H for cleaning the evaporator helix between +64 m and +46 m.
In the second step another four water cannons were added to each boiler for cleaning the membrane walls in the burner area between +46 m and +16 m.

Conclusion

Table 2 summaries the main factor taken into account in assessing the economics of furnace cleaning with the new water cannons in Weisweiler G and H (eight cannons per boiler), compared with conventional cleaning technology using 116 water blowers of the SK58 type. The factors were indexed to the costs of the water cannon installation. Taking into account these input parameters, the feasibility study suggested a payback period of about seven years.