Fluidized bed combustion

In its most basic form, fuel particles are suspended in a hot, bubbling fluidity bed of ash and other particulate materials (sand, limestone etc.)

The resultant fast and intimate mixing of gas and solids promotes rapid heat transfer and chemical reactions within the bed.

In addition, for any given thermal duty, FBCs are smaller than the equivalent conventional furnace, so may offer significant advantages over the latter in terms of cost and flexibility.

The mixing action of the fluidized bed brings the flue gases into contact with a sulfur-absorbing chemical, such as limestone or dolomite.

However, they have some disadvantages such as erosion on the tubes inside the boiler, uneven temperature distribution caused by clogs on the air inlet of the bed, long starting times reaching up to 48 hours in some cases.