| 摘要 |
PROBLEM TO BE SOLVED: To specially decrease the height of a boiler furnace main body so as to make it compact and lower the manufacture and construction cost of a boiler. SOLUTION: In a boiler, a convection heat transfer part 5 for receiving the sensible heat of combustion exhaust gas is connected to an outlet on the upper part of a furnace main body 101 on which a main burner 2 is mounted and whose periphery is formed by a water tube. The convection heat transfer part 5 is provided with a steam superheater 5 for further heating boiler water heated in the water tube of the furnace main body 101 to generate steam. An economizer 106 heats the boiler water at high temperature before it is supplied to the water tube of the furnace main body 101. In the upstream side of the economizer 106, a heater 201 for air of high temperature is arranged to perform a heat exchange between high temperature combustion exhaust gas 115 from the steam superheater 5a and air 116 for combustion to be supplied to the main burner 2 and heating the air 116 for combustion preferably at 300 deg.C or higher (in this embodiment, 500 to 800 deg.C). |
