Staged Combustion Method and Apparatus

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.

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.

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.

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.

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.

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.

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.

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.

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.