Internal circulation fluidized bed (ICFB) combustion system and method of operation thereof

A fluidized bed combustion system (10) particularly suited for use to effect the incineration, i.e., combustion, therewith of wood waste/sludge mixtures that have high moisture and ash content which makes them difficult to burn. The fluidized bed combustion system (10) includes a fluidized bed combustor (12) embodying a fluidized bed (24) composed of bed solids. Air is injected into the fluidized bed (24) through an air distributor (28) to establish a first controlled fluidizing velocity zone and a second controlled fluidizing velocity zone therewithin. Material (42b) is introduced into the fluidized bed combustor (12) above the second controlled fluidizing velocity zone. Bed solids are projected from the first controlled fluidizing velocity zone to the second controlled fluidizing velocity zone whereupon the bed solids rain down upon the material (42b) and effect a covering thereof. The material (42b) is then dried and thereafter combusted. Inerts/tramp materials/clinkers as well as large diameter solids entrained with the material (42b) are segregated therefrom and then are removed (14,200) from the fluidized bed combustor (12).