Patent ID: 6907845

Claim:
A Rankine cycle steam generator system which system comprises: a boiler having a fuel combustion zone and radiant heat and convective heat transfer zones for producing steam; an insulated Gas Primer Sector (GPS) combined with the boiler so that an exhaust gas stream therefrom flows through the GPS; the GPS including means for removing particulate from the exhaust gas stream and means for transferring heat to a combustion gas stream by indirect counterflow heat exchange with the exhaust gas stream over an extended residence time, the result of which heat transfer is the reduction of the temperature of the exhaust gas stream to a temperature where moisture condenses; means for supplying said combustion gas stream to the GPS where it is heated in indirect counterflow heat exchange with the exhaust gas stream over an extended residence time to reach a temperature of at least about 500° F. (260° C.); insulated duct means for conveying the heated combustion gas stream exiting the GPS to the boiler combustion zone for fuel combustion therein; and means for removing particulate from the GPS.