Staged Combustion Method and Apparatus

Abstract

A primary reactant stream is injected from a burner port into a combustion chamber along an axis. Staged reactant streams are injected into the combustion chamber adjacent to the primary reactant stream in differing configurations. The differences between the configurations of the staged reactant streams include differences in radial distance from the burner port, axial distance from the burner port, and direction relative to the axis. The reactant streams are shifted between differing modes, with differences between the modes including the presence or absence of a flame at the burner port, differences in fuel flow rates, and differences in combustion air flow rates. A heat release profile developed by combustion of the primary reactant stream, or the length of a flame developed by combustion of the primary reactant stream, can be controlled by shifting between the differing modes with reference to the heat release profile or the length of the flame.

1 . A method comprising:
 injecting primary fuel and combustion air premix from a burner port into a combustion chamber;   injecting secondary fuel without combustion air into the combustion chamber from a secondary fuel injector port located adjacent to the burner port;   injecting tertiary fuel without combustion air into the combustion chamber from a tertiary fuel injector port located adjacent to and downstream from the secondary fuel injector port;   sensing temperatures at spaced-apart locations in the combustion chamber; and   initiating, regulating, and terminating delivery of fuel to the secondary and tertiary fuel injector ports separately from each other in response to the sensed temperatures while continuing to inject fuel and combustion air premix from the burner port into the combustion chamber, whereby the method can control and varying a heat release profile corresponding to the sensed temperatures.   
     
     
         2 . A method as defined in  claim 1  including a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air premix are being injected from the burner port, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port. 
     
     
         3 . A method as defined in  claim 1  including a mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port, a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air premix are being injected from the burner port, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port. 
     
     
         4 . A method as defined in  claim 1  including the steps of (a) delivering fuel and combustion air to the burner at a lean fuel to oxidant ratio and simultaneously (b) delivering fuel to the burner, the secondary fuel injector port, and the tertiary fuel injector port at an overall rate that is stoichiometric relative to the combustion air delivered to the burner. 
     
     
         5 . A method as defined in  claim 1  further comprising the steps of (a) detecting the presence and absence of a flame projecting from the burner port, (b) initiating, terminating, and regulating the delivery of fuel and combustion air to the burner in a flame mode in the presence of a detected flame, and (c) initiating, regulating, and terminating the delivery of fuel and combustion air to the burner in a diffuse combustion mode in the absence of a detected flame. 
     
     
         6 . A method as defined in  claim 5  further comprising the steps of (d) initiating, regulating, and terminating the delivery of fuel to the secondary and tertiary fuel injector ports separately from each other while delivering fuel and combustion air to the burner in the flame mode and in the diffuse combustion mode. 
     
     
         7 . A method comprising:
 injecting primary fuel and combustion air premix from a burner port into a combustion chamber to project a flame downstream from the burner port;   lengthening the flame by injecting second stage fuel without combustion air into the combustion chamber from a secondary fuel injector port located adjacent to the burner port;   further lengthening the flame by injecting third stage fuel without combustion air into the combustion chamber from a tertiary fuel injector port located adjacent to and downstream from the secondary fuel injector port;   operating a sensor system that senses the length of the flame; and   controlling and varying the length of the flame by initiating, regulating, and terminating delivery of fuel to the secondary and tertiary fuel injector ports in response to the sensor system separately from each other while continuing to inject primary fuel and combustion air premix from the burner port into the combustion chamber.   
     
     
         8 . A method as defined in  claim 7  including a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air premix are being injected from the burner port, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port. 
     
     
         9 . A method as defined in  claim 7  including a mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port, a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air premix are being injected from the burner port, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air premix are being injected from the burner port. 
     
     
         10 . A method as defined in  claim 7  further comprising, while controlling and varying the length of the flame, the steps of (a) delivering fuel and combustion air to the burner at a lean fuel-to-oxidant ratio and (b) simultaneously delivering fuel to the burner, the secondary fuel injector port, and the tertiary fuel injector port at an overall rate that is stoichiometric relative to the combustion air delivered to the burner. 
     
     
         11 . A method comprising:
 injecting primary fuel and combustion air premix from a burner port into a combustion chamber;   injecting second stage fuel without combustion air into the combustion chamber from a secondary fuel injector port located adjacent to the burner port;   injecting third stage fuel without combustion air into the combustion chamber from a tertiary fuel injector port located adjacent to and downstream from the secondary fuel injector port;   detecting the presence and absence of a flame projecting along the axis;   initiating, terminating, and regulating delivery of fuel and combustion air to the burner in a flame mode in the presence of the flame;   initiating, regulating, and terminating delivery of fuel and combustion air to the burner in a diffuse combustion mode in the absence of the flame; and   initiating, regulating, and terminating delivery of fuel to the secondary and tertiary fuel injector ports separately from each other while delivering primary fuel and combustion air to the burner in the flame mode and in the diffuse combustion mode.   
     
     
         12 . A method as defined in  claim 11  including a flame mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a flame mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         13 . A method as defined in  claim 11  including a flame mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a flame mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a flame mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         14 . An apparatus as defined in  claim 11  including a diffuse combustion mode in which fuel is delivered to the secondary fuel injector ports but not to the tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, and a diffuse combustion mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         15 . A method as defined in  claim 11  including a diffuse combustion mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a diffuse combustion mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a diffuse combustion mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         16 . A method comprising:
 injecting a primary reactant stream from a burner port into a combustion chamber along an axis;   injecting staged reactant streams into the combustion chamber adjacent to the primary reactant stream in differing configurations, with differences between the configurations including radial distance from the burner port, axial distance from the burner port, and direction relative to the axis; and   shifting the reactant streams between differing modes, with differences between the modes including the presence or absence of a flame at the burner port, and differences in fuel flow rates.   
     
     
         17 . A method as defined in  claim 16  further comprising the steps of sensing temperatures at spaced-apart locations in the combustion chamber, and shifting between the differing modes with reference to the sensed temperatures, whereby the method can control a heat release profile corresponding to the sensed temperatures. 
     
     
         18 . A method as defined in  claim 16  further comprising the steps of sensing a flame length in the combustion chamber, and controlling the flame length by shifting between the differing modes with reference to the flame length. 
     
     
         19 . A method comprising:
 injecting a stream of fuel and combustion air premix from a burner port into a furnace combustion chamber along an axis;   shifting the premix stream between differing primary modes, with differences between the primary modes including differences in fuel-to-oxidant ratio and the presence or absence of a flame at the burner port;   injecting staged reactant streams into the combustion chamber adjacent to the premix stream in differing configurations, with differences between the configurations including differences in radial distance from the burner port, axial distance from the burner port, and direction relative to the axis; and   shifting the staged reactant streams between differing staged modes, with differences between the staged modes including differences in fuel flow rates.   
     
     
         20 . A method as defined in  claim 19  further comprising the steps of sensing temperatures at spaced-apart locations in the combustion chamber, and shifting between the differing modes with reference to the sensed temperatures, whereby the method can control a heat release profile corresponding to the sensed temperatures. 
     
     
         21 . A method as defined in  claim 19  further comprising the steps of sensing a flame length in the combustion chamber, and controlling the flame length by shifting the primary and staged reactant streams between modes with reference to the flame length. 
     
     
         22 . An apparatus comprising:
 a structure defining a combustion chamber;   a burner port configured to inject a primary reactant stream into the combustion chamber along an axis;   injector ports located adjacent to the burner port and configured to inject staged reactants into the combustion chamber in streams having differing configurations, with differences between the configurations including differences in radial distance from the burner port, axial distance from the burner port, and direction relative to the axis; and   a system that controls delivery of reactants to the burner port and the injector ports in differing modes, and that switches between differing modes while continuing to deliver reactants to the burner port, with differences between the modes including the presence or absence of a flame projecting from the burner port, differences in fuel flow rates, and differences in premix flow rates.   
     
     
         23 . An apparatus as defined in  claim 22  including a sensor system that senses temperatures at spaced-apart locations in the combustion chamber, and a controller configured to shift between the differing modes in response to the sensor system, whereby the controller can control a heat release profile corresponding to the sensed temperatures. 
     
     
         24 . An apparatus as defined in  claim 22  including a sensor system that senses the length of a flame in the combustion chamber, and a controller configured to control the length of the flame by shifting between the differing modes in response to the sensed temperatures. 
     
     
         25 . An apparatus comprising:
 a structure defining a combustion chamber;   a premix burner port configured to inject a primary reactant stream into the combustion chamber along an axis;   injector ports located adjacent to the burner port and configured to inject staged reactants into the combustion chamber in streams having differing configurations, with differences between the configurations including differences in radial distance from the burner port, axial distance from the burner port, and direction relative to the axis; and   a system that delivers reactants to the burner port and the injector ports in differing modes, and that switches between the differing modes while continuing to deliver reactants to the burner port, with differences between the modes including the presence or absence of a flame projecting from the burner port, differences in fuel flow rates, and differences in premix flow rates.   
     
     
         26 . An apparatus as defined in  claim 25  including a sensor system that senses temperatures at spaced-apart locations in the combustion chamber, and a controller configured to shift between the modes in response to the sensed temperatures, whereby the controller can control a heat release profile corresponding to the sensed temperatures. 
     
     
         27 . An apparatus as defined in  claim 25  including a sensor system that senses a flame length in the combustion chamber, and a controller configured to control the flame length by shifting between the differing modes in response to the sensor system. 
     
     
         28 . An apparatus comprising:
 a structure defining a combustion chamber;   a premix burner having a port configured to inject primary fuel and combustion air premix into the combustion chamber;   a secondary fuel injector port located adjacent to the burner port and configured to inject second stage fuel without combustion air into the combustion chamber;   a tertiary fuel injector port located adjacent to the secondary fuel injector port and configured to inject third stage fuel without combustion air into the combustion chamber downstream of the secondary fuel injector port;   a sensor system that senses temperatures at spaced-apart locations in the combustion chamber; and   a controller configured to initiate, regulate and terminate delivery of fuel to the secondary and tertiary fuel injector ports separately from each other in response to the sensor system while delivering fuel and combustion air to the burner, whereby the controller can control and vary a heat release profile corresponding to the sensed temperatures.   
     
     
         29 . An apparatus as defined in  claim 28  wherein the controller is configured to operate in a plurality of differing modes including a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         30 . An apparatus as defined in  claim 28  wherein the controller is configured to operate in a plurality of differing modes including a mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         31 . An apparatus as defined in  claim 28  wherein the controller is configured to (a) deliver fuel and combustion air to the burner at a lean fuel-to-oxidant ratio and to simultaneously (b) deliver fuel to the burner, the secondary fuel injector port, and the tertiary fuel injector port at an overall rate that is stoichiometric relative to the combustion air delivered to the burner. 
     
     
         32 . An apparatus as defined in  claim 28  further comprising a detector that detects the presence and absence of a flame projecting along the axis; and wherein the controller is configured with reference to the detector to (a) initiate, terminate, and regulate the delivery of fuel and combustion air to the burner in a flame mode in the presence of a flame, and to (b) initiate, regulate, and terminate the delivery of fuel and combustion air to the burner in a diffuse combustion mode in the absence of a flame. 
     
     
         33 . An apparatus as defined in  claim 32  wherein the controller is further configured to (c) initiate, regulate, and terminate the delivery of fuel to the secondary and tertiary fuel injector ports separately from each other while delivering fuel and combustion air to the burner in the flame mode and in the diffuse combustion mode. 
     
     
         34 . An apparatus comprising:
 a structure defining a combustion chamber;   a premix burner having a port configured to inject primary fuel and combustion air premix into the combustion chamber to project a flame downstream from the burner port;   a secondary fuel injector port located adjacent to the burner port and configured to lengthen the flame by injecting second stage fuel without combustion air into the combustion chamber separately from the burner port;   a tertiary fuel injector port located adjacent to the secondary fuel injector port and configured to further lengthen the flame by injecting third stage fuel without combustion air into the combustion chamber downstream of the secondary fuel injector port;   a sensor system that senses the length of the flame; and   a controller configured to control and vary the flame length by initiating, regulating, and terminating delivery of fuel to the secondary and tertiary fuel injector ports in response to the sensor system separately from each other while delivering fuel and combustion air to the burner.   
     
     
         35 . An apparatus as defined in  claim 34  wherein the controller is configured to operate in a plurality of differing modes including a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         36 . An apparatus as defined in  claim 34  wherein the controller is configured to operate in a plurality of differing modes including a mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         37 . An apparatus as defined in  claim 34  wherein the controller is configured to (a) deliver fuel and combustion air to the burner at a lean fuel-to-oxidant ratio and to simultaneously (b) deliver fuel to the burner, the secondary fuel injector port, and the tertiary fuel injector port at an overall rate that is stoichiometric relative to the combustion air delivered to the burner while (c) varying the flame length. 
     
     
         38 . An apparatus comprising:
 a structure defining a combustion chamber;   a premix burner having a port configured to inject primary fuel and combustion air premix into the combustion chamber along an axis;   a secondary fuel injector port located adjacent to the burner port and configured to inject second stage fuel without combustion air into the combustion chamber;   a tertiary fuel injector port located adjacent to the secondary fuel injector and configured to further inject third stage fuel without combustion air into the combustion chamber downstream of the secondary fuel injector;   a detector that detects the presence and absence of a flame projecting along the axis; and   a controller configured with reference to the detector to (a) initiate, terminate, and regulate delivery of fuel and combustion air to the burner in a flame mode in the presence of the flame, to (b) initiate, regulate, and terminate delivery of fuel and combustion air to the burner in a diffuse combustion mode in the absence of the flame, and to (c) initiate, regulate, and terminate delivery of fuel to the secondary and tertiary fuel injector ports separately from each other while delivering fuel and combustion air to the burner in the flame mode and in the diffuse combustion mode.   
     
     
         39 . An apparatus as defined in  claim 38  wherein the controller is configured to operate in a plurality of differing flame modes including a flame mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a flame mode in which fuel is delivered to both the secondary and tertiary fuel injectors ports while fuel and combustion air are being delivered to the burner. 
     
     
         40 . An apparatus as defined in  claim 38  wherein the controller is configured to operate in a plurality of differing flame modes including a flame mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a flame mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a flame mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         41 . An apparatus as defined in  claim 38  wherein the controller is configured to operate in a plurality of differing diffuse combustion modes including a diffuse combustion mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a diffuse combustion mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner. 
     
     
         42 . An apparatus as defined in  claim 38  wherein the controller is configured to operate in a plurality of differing diffuse combustion modes including a diffuse combustion mode in which no fuel is delivered to the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner, a diffuse combustion mode in which fuel is delivered to the secondary fuel injector port but not to the tertiary fuel injector port while fuel and combustion air are being delivered to the burner, and a diffuse combustion mode in which fuel is delivered to both the secondary and tertiary fuel injector ports while fuel and combustion air are being delivered to the burner.