Patent ID: 7146916

Claim:
An inclined hearth combustor including a primary combustion chamber defined by at least two stepped hearths fixed with respect to each other and an ash transfer ram movably disposed between said two stepped hearths, at least one of said hearths comprising at least two spaced rows of air feed-tubes longitudinally embedded therein, said air feed-tubes terminating at a front face of said hearth for delivering a combustion gas into said combustion chamber, said combustor further comprising: a secondary combustion chamber in communication with said stepped hearth combustion chamber, said secondary combustion chamber including a refractory-lined cyclone separator for removing fly ash from combustion gases exiting said stepped hearth combustion chamber; and a boiler having an inlet in communication with said secondary combustion chamber, said boiler inlet being surrounded by said cyclone separator, wherein said cyclone separator includes a flue gas recirculating inlet for feeding heated flue gas from said boiler into said secondary combustion chamber.