Abstract: A boiler having a furnace, a tunnel section and a rear gas duct is improved by the fact that a partition wall at right angles to side walls of the rear gas duct is disposed in the rear gas duct to divide it into two passages. A low-pressure reheater is disposed in the divided passage nearest to the tunnel section and has a narrow width. Two partition walls are disposed in the other divided passage parallel to the side walls of the rear gas duct to further divide the passage into three passages. Superheaters are disposed in the further divided passages close to the side walls and a high-pressure reheater is disposed in the central further divided passage. In another embodiment, the locations of the superheater and the high-pressure reheater are reversed.

Abstract: A boiler having a discharge gas duct divided into a plurality of passages, respective passages having reheaters and superheaters therein. Gas flow controllers are provided for adjusting combustion gas flow through the respective passages. Evaporators are provided in the passages which have reheaters therein, the convective evaporators being downstream of the respective reheaters.

Abstract: A forced-flow once-through boiler for variable supercritical pressure operation comprises burners, water-wall tubes constituting the surrounding walls of a furnace and which are themselves made up of banks of vertical generating tubes for simultaneous upward flow, and a convection-heating type evaporator mounted between the outlets of the water-wall tubes and a water separator.