Operating method

Abstract

A method of operating a fluidized bed system, typically as a combustor system for power or steam generation by burning high-sulfur coal, which comprises forming an entrained fluidized bed in a first space region containg a first solid bed particle component, such as a hematite ore containing over 90% Fe.sub.2 O.sub.3, or limestone, forming in a more limited space region within the first region a dense fluidized bed containing a second solid bed particle component, such as larger particles of the hematite, essentially comprising a material having long-term physical and chemical stability in the fluidized bed system so as to be substantially non-agglomerating and not subject to substantial attrition therein, providing a recirculation path such as through a cyclone separator and particle reservoir for the first particle component from the first space region through the dense fluidized bed in the more limited space region, and operating the fluidized bed system at a velocity such that the second component particles are effectively retained in the dense fluidized bed in the more limited space region, whereas the first component particles recirculate and interpenetrate therethrough, commingling with the second component particles.