Performance of Water Cannons at Labadie

Amerens Labadie station consists of 4 coal fired 600 megawatt size generating units. Unit 1 installed water cannon furnace cleaning devices during a spring outage this year. Water cannons were selected to clean the deposits that result from combustion of Powder River Basin (PRB) coal at the Labadie power plant. This paper describes the evaluation of methods of cleaning furnace walls and the selection, installation, and startup experience with water cannons. Cleaning the furnace results in an increase in boiler efficiency that is translated into improved heat rate and improved cost of plant operation. Benefits from water cannon installation are described along with the problems encountered. PRB fuel combustion results in tenacious deposits that inhibit heat transfer on furnace walls. PRB coal typically has a lower ash fusion temperature than bituminous coals which leads to ash slag formation in furnaces that have been changed to PRB from the fuel the boiler was originally designed for. Often the deposit from PRB fuel is of a minimal thickness, however the reflectivity of the deposit creates a high barrier to radiant heat transfer. High Furnace Exit Gas Temperature (FEGT) indicates poor heat transfer in the furnace area and this increases the formation of slag in convection passes. Cleaning of furnace surface is critical to maximizing the heat absorption of the furnace and reducing the FEGT. The increased clean capability of the water cannons compared to existing wall blowers will be compared in this paper.