Solid fuel burner and combustion device using same

Abstract

A solid fuel burner and a combustion device using the solid fuel burner includes: a throat provided to the outer periphery of a fuel nozzle and injecting combustion gas into a furnace; a duct for delivering the combustion gas to the throat, the duct being provided with an inlet opening into which the gas is introduced from a direction perpendicular to the central axis of the nozzle and having a flow path formed so as to be bent at a right angle in the direction of the central axis of the nozzle; a damper provided in the duct; and a differential pressure detection device for detecting the difference between the pressure of the combustion gas flowing through the upstream portion of the duct and the pressure of the combustion gas flowing through the downstream portion of the duct. The damper is provided near and downstream of the inlet opening of the duct.

1 . A solid fuel burner comprising:
 a cylindrical fuel nozzle that discharges a mixed fluid of a solid fuel and a carrier gas into a furnace from a wall surface of the furnace;   a cylindrical combustion gas throat that is provided at an outer periphery of the fuel nozzle and discharges a combustion gas into the furnace;   a duct that constitutes a flow path for the combustion gas that is connected to the combustion gas throat;   flow rate adjusting means for the combustion gas that is provided in the duct; and   a differential pressure detection device that detects a pressure difference between the combustion gases flowing on the upstream side and the downstream side in the duct,   wherein the duct has an inlet opening into which the combustion gas is taken from one direction orthogonal to a central axis direction of the fuel nozzle and is formed in such a manner that the flow path for the combustion gas is bent at a right angle in the central axis direction of the fuel nozzle,   the flow rate adjusting means for the combustion gas is provided near the inlet opening of the duct on the downstream side of the inlet opening,   the differential pressure detection device has an upstream-side pressure detection point on an inner wall of the duct that is the farthest from the inlet opening of the duct corresponding to a stagnation region of the combustion gas on a wake side of the flow rate adjusting means, and has a downstream-side pressure detection point on an outer wall of the combustion gas throat, and   a control device is provided, the control device converting a value of a pressure difference at the upstream-side pressure detection point and the downstream-side pressure detection point detected by the differential pressure detection device into a flow rate of the combustion gas and operating the flow rate adjusting means to adjust a flow rate of the combustion gas.   
     
     
         2 . The solid fuel burner according to  claim 1 ,
 wherein the flow path for the combustion gas in the duct that is connected to the combustion gas throat is divided by a partition wall into a plurality of flow paths that the combustion gas does not flow from one flow path to another, and   the upstream-side pressure detection point and the downstream-side pressure detection point are provided to each of the plurality of flow paths.   
     
     
         3 . The solid fuel burner according to  claim 1 ,
 wherein the downstream-side pressure detection point is provided on the combustion gas throat where an interval between the combustion gas flow paths in a radial direction becomes maximum with the central axis of the fuel nozzle being determined as a reference.   
     
     
         4 . The solid fuel burner according to  claim 1 ,
 wherein the differential pressure detection device is configured to detect a value of a differential pressure between an upstream-side pressure and a downstream-side pressure of the combustion gas in the duct through respective pressure conduits constituting the upstream-side pressure detection points and the downstream-side pressure detection points.   
     
     
         5 . A combustion apparatus comprising solid fuel burners according to  claim 1  on a plurality of stages along an up-and-down direction and in a plurality of rows along a furnace width direction on a wall surface of a furnace,
 wherein the combustion apparatus comprises solid fuel flow rate measuring means for individually adjusting and measuring flow rates of a solid fuel that flows into the plurality of solid fuel burners, 
 and a control device is configured to adjust an opening degree of flow rate adjusting means for a combustion gas based on a combustion gas flow rate detected by a differential pressure detection device of each solid fuel burner in accordance with a change in solid fuel flow rate measured by the solid fuel flow rate measuring means, and to individually control each flow rate of the combustion gas.