Abstract
A CFM-bed (Combined Fast Fluidized Bed and Moving Bed) gas-solid contactor was applied to a solid fuel combustor. This combustor was proposed as a promising solid-fuel combustor with high efficiency and a countermeasure against environmental pollution. The combustor is composed of a set of double pipes. A fast fluidized bed and/or an entrained bed is formed in the inner pipe where partial combustion of coal particles may take place. A moving bed is made at the outlet of the annular part wherechar combustion may happen.
In the present study, Loy Yang coal and coke were used as a typical low-grade solid fuel. Rich and lean combustion limits were experimentally investigated with a single-staged combustion mode by changing the primary air ratio. It was confirmed that this combustor could be operated successfully in a wide operational range of primary air ratio from 0.3 to 2.4. The principal ignition mechanism of the fule in this combustor was made clear by considering not only internal particle circulation but also the exhaust heat recirculation from the annular part to the inner pipe.
