Wet Bottom Furnace - Wet-bottom Boilers

Wet-bottom Boilers

1. Slag-tap boiler, burns pulverized coal. 50 percent of the ash is retained in the furnace as boiler slag.
2. Cyclone boiler, burns crushed coal. 70 to 80 percent of the ash is retained as boiler slag. The rest of the ash leaves as fly ash.

If the ash fusion temperature is less than the furnace temperature then that type of furnace is called a wet bottom furnace.