Upgrading coal and other carbonaceous fuels using a lean fuel gas stream from a pyrolysis step

摘要

A method for upgrading coal and other carbonaceous fuels includes subjecting the carbonaceous fuel to a pyrolyzing process, thereby forming upgraded carbonaceous fuel and a flow of lean fuel gases. Auxiliary fuel is combusted in an auxiliary fuel combustor to produce auxiliary fuel combustion gases, and the lean fuel gases are heated with the auxiliary fuel combustion gases. The heated lean fuel gases are combusted in a lean fuel combustor, thereby producing a gas stream of products of combustion, and at least a portion of the gas stream of products of combustion are directed to the pyrolyzer.