Boiler and method for adjusting temperature of steam output from boiler

Abstract

A boiler according to the present invention is a boiler configured to make combustion gas originating from combustion in a burner ( 101 ) flow from a furnace ( 102 ) and pass through a super heater (SH) ( 104 ) and an evaporation tube bank ( 105 ). The boiler includes a downstream shield plate ( 11 A) that is slidable in the vertical direction of the super heater ( 104 ) at a position downstream of the combustion gas flowing above the super heater ( 104 ), thereby regulating the flow rate of combustion gas entering the upper space A of the super heater ( 104 ). By regulating the flow rate of bypass gas ( 12 ) with the downstream shield plate ( 11 A) and in turn regulating the flow rate of mainstream gas ( 13 ), the temperature of steam output from the super heater ( 104 ) is controlled.

1 . A boiler that flows combustion gas produced by combustion in a burner through a super heater and an evaporation tube bank from a furnace, the boiler comprising:
 a shield plate that is configured to be slidable in a vertical direction of the super heater or to be rotatable about one end as a rotation axis in order to allow adjustment of an opening degree thereof, the shield plate being provided at any one or both of an upstream side and a downstream side of the combustion gas flowing above the super heater, wherein   a flow rate of the combustion gas entering an upper space of the super heater is regulated.   
     
     
         2 . The boiler according to  claim 1 , wherein
 a temperature of a part of steam extracted in midstream of the super heater is reduced with a water drum, and the steam is provided to the super heater again, so that a temperature of steam of the super heater is adjusted.   
     
     
         3 . A method for adjusting a temperature of steam of a boiler that flows combustion gas produced by combustion in a burner through a super heater and an evaporation tube bank from a furnace, the method comprising:
 providing a shield plate that is configured to be slidable in a vertical direction of the super heater or to be rotatable about one end as a rotation axis in order to allow adjustment of an opening degree thereof, the shield plate being provided at any one or both of an upstream side and a downstream side of the combustion gas flowing above the super heater; and   adjusting a flow rate of the combustion gas entering an upper space of the super heater by adjusting a sliding degree or the opening degree of the shield plate.   
     
     
         4 . The method for adjusting a temperature of steam of a boiler according to  claim 3 , wherein
 a part of steam is extracted in midstream of the super heater, a temperature of the steam thus extracted is reduced with a water drum, and the steam is provided to the super heater again, so that a temperature of steam of the super heater is adjusted.