EP3669121A1 - Système de commande pour brûleur à stabilisateur de flamme perforé - Google Patents
Système de commande pour brûleur à stabilisateur de flamme perforéInfo
- Publication number
- EP3669121A1 EP3669121A1 EP18836068.9A EP18836068A EP3669121A1 EP 3669121 A1 EP3669121 A1 EP 3669121A1 EP 18836068 A EP18836068 A EP 18836068A EP 3669121 A1 EP3669121 A1 EP 3669121A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- preheating
- flame holder
- combustion system
- sensor
- perforated flame
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
- F23D14/82—Preventing flashback or blowback
- F23D14/825—Preventing flashback or blowback using valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
- F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/32—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/48—Nozzles
- F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/70—Baffles or like flow-disturbing devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details, e.g. noise reduction means
- F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
- F23D14/82—Preventing flashback or blowback
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
- F23N5/242—Preventing development of abnormal or undesired conditions, i.e. safety arrangements using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
- F23N5/006—Systems for controlling combustion using detectors sensitive to combustion gas properties the detector being sensitive to oxygen
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
- F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
- F23R3/02—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration
- F23R3/16—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration with devices inside the flame tube or the combustion chamber to influence the air or gas flow
- F23R3/18—Flame stabilising means, e.g. flame holders for after-burners of jet-propulsion plants
Definitions
- Embodiments include a combustion system including a perforated flame holder.
- the combustion system is configured to operate in a preheating state and in a standard operating state.
- the combustion system supports a preheating flame with a preheating fuel and an oxidant.
- the preheating flame is positioned to heat the perforated flame holder to an operating temperature.
- the perforated flame holder holds a combustion reaction of a main fuel and an oxidant.
- the main fuel and the preheating fuel may be the same fuel.
- the main fuel and/or the preheating fuel may include fuel mixtures.
- the main fuel and the preheating fuel are natural gas.
- combustion system includes a
- preheating flame sensor configured to sense a condition of the preheating flame and to output sensor signals indicative of the condition of the preheating flame.
- the combustion system includes a perforated flame holder sensor configured to sense a condition of the perforated flame holder or a
- the combustion system includes a controller configured to receive the sensor signals from the preheating flame sensor and the perforated flame holder sensor.
- the controller is configured to execute software instructions stored on a non-transitory computer readable medium to automatically adjust parameters of the combustion system and to
- the controller adjusts the combustion system and transitions between states by controlling one or more actuators configured to adjust components of the combustion system.
- a flame stability sensor is positioned to sense a flame condition (e.g., the presence or absence of a flame) in a region between the (e.g., main) fuel nozzles and the perforated flame holder, said region being found by the inventors to characterize a main combustion reaction instability.
- the flame stability sensor may be positioned half way between the fuel nozzles and the perforated flame holder.
- the controller may, upon receipt of an instability signal from the flame stability sensor corresponding to at least transient presence of a flame in the positioned region and responsively execute a logical decision that the combustion reaction instability exists, at least transiently.
- the controller may responsively write an incident of combustion reaction instability to a log file and/or cause an electronic display state corresponding to the incident o be provided to an operating engineer or the like.
- the controller may cause one or more actuators to modify an operating condition to increase main combustion reaction stability.
- the controller may cause actuation of a flame blow off apparatus to increase fluid flow velocity or fluid cooling between the fuel nozzles and the perforated flame holder, cause a damper to open to increase air volume delivery, cause a blower to increase power to increase air volume delivery, cause a valve to momentarily pause fuel delivery, and/or cause a perforated flame holder heater to activate.
- a combustion system including a perforated flame holder.
- the combustion system is configured to operate in a preheating state and in a standard operating state.
- the combustion system supports a preheating flame with a preheating fuel and an oxidant.
- the preheating flame is positioned to heat the perforated flame holder to an operating temperature.
- the perforated flame holder holds a combustion reaction of a main fuel and an oxidant.
- the combustion system includes a preheating flame sensor configured to sense a condition of the preheating flame and to output sensor signals indicative of the condition of the preheating flame.
- the combustion system includes a perforated flame holder sensor configured to sense a condition of the perforated flame holder and to output sensor signals indicative of the condition of the perforated flame holder.
- the combustion system includes a controller configured to receive the sensor signals from the preheating flame sensor and the perforated flame holder sensor.
- the controller is configured to execute software instructions stored on a non-transitory computer readable medium to output messages on a display prompting an operator of the combustion system to adjust parameters of the combustion system and to transition the combustion system between the preheating state and the standard operating state responsive to the sensor signals from the perforated flame holder sensor and the preheating flame holder sensor.
- One embodiment is a combustion system including a perforated flame holder.
- the combustion system is configured to operate in a preheating state and in a standard operating state.
- the combustion system supports a preheating flame with a preheating fuel and an oxidant.
- the preheating flame is positioned to heat the perforated flame holder to an operating temperature.
- the perforated flame holder holds a combustion reaction of a main fuel and an oxidant.
- the combustion system includes a preheating flame sensor configured to sense a condition of the preheating flame and to output sensor signals indicative of the condition of the preheating flame.
- the combustion system includes a perforated flame holder sensor configured to sense a condition of the perforated flame holder and to output sensor signals indicative of the condition of the perforated flame holder.
- the combustion system includes a controller configured to receive the sensor signals from the preheating flame sensor and the perforated flame holder sensor.
- the controller is configured to execute software instructions stored on a non-transitory computer readable medium to adjust parameters of the combustion system and to transition the combustion system between the preheating state and the standard operating state responsive to the sensor signals from the perforated flame holder sensor and the preheating flame holder sensor.
- the controller is configured to output messages on a display prompting an operator of the combustion system to approve adjusting parameters of the combustion system or transitioning between the preheating state and the standard operating state responsive to the sensor signals.
- the controller adjusts the combustion system and transitions between states by controlling one or more actuators configured to adjust components of the combustion system if the operator indicates approval of the adjustment or the transition.
- the controller can also maintain desired combustion within the perforated flame holder via control of actuators in accordance with sensor signals output by the various sensors of the combustion system. Additionally, or alternatively, the controller may be configured to operate in an automatic mode wherein the controller
- the controller preferably creates a log file to indicate sensed parameters and/or actuations performed under automatic control.
- FIG. 1 is a block diagram of a combustion system including a
- perforated flame holder perforated flame holder, according to an embodiment.
- FIG. 2 is a simplified diagram of a combustion system including a perforated flame holder configured to hold a combustion reaction, according to an embodiment.
- FIG. 3 is a side sectional diagram of a portion of the perforated flame holder of FIGS. 1 and 2, according to an embodiment.
- FIG. 4 is a flow chart showing a method for operating a burner system including the perforated flame holder of FIGS. 1-3, according to an
- FIG. 5A is a simplified diagram of a combustion system including a reticulated ceramic perforated flame holder configured to hold a combustion reaction, according to an embodiment.
- FIG. 5B is a side sectional diagram of a portion of the reticulated ceramic perforated flame holder of FIG. 5A, according to an embodiment.
- FIG. 6 is a block diagram of components of a combustion system, according to an embodiment.
- FIG. 7 is a flow diagram of a process for operating a combustion system, according to an embodiment.
- FIG. 8 is a flow diagram of a process for operating a combustion system, according to an embodiment.
- FIG. 9 is a flow diagram of a process for operating a combustion system, according to an embodiment.
- FIG. 10A is a diagram of a combustion system, according to an embodiment.
- FIG. 10B is a diagram of the combustion system of FIG. 10A in a preheating state, according to an embodiment.
- FIG. 10C is a diagram of the combustion system of FIG. 10A in standard operating state, according to an embodiment.
- FIG. 11 is a diagram of a combustion system, according to an embodiment.
- FIG. 1 is a diagram of a combustion system 100 including a perforated flame holder (perforated flame holder) 102, according to an embodiment.
- the combustion system 100 is configured to preheat the perforated flame holder 102 to an operating temperature at which the perforated flame holder 102 can sustain a combustion reaction of a main fuel and an oxidant at least partially within the perforated flame holder 102.
- the combustion system 100 is configured to operate in two general operating conditions: a preheating state and a standard operating state. In the preheating state, the combustion system 100 preheats the perforated flame holder 102 to the operating temperature.
- the combustion system 100 transitions to the standard operating state in which the perforated flame holder 102 holds a combustion reaction of the main fuel and the oxidant at least partially within the perforated flame holder 102.
- the perforated flame holder 102 holds a majority of a combustion reaction of the main fuel and oxidant within the perforated flame holder 102.
- the combustion system 100 utilizes an oxidant source 104, a preheating fuel distributor 106, and a preheating fuel source 108 in the preheating state.
- the oxidant source 104 outputs an oxidant into the furnace volume in which the perforated flame holder 102 is positioned.
- the preheating fuel source 108 supplies a preheating fuel to the preheating fuel distributor 106.
- the preheating fuel distributor 106 outputs the preheating fuel into the furnace volume.
- the preheating fuel and the oxidant mix together in the furnace volume.
- the combustion system 100 utilizes an igniter to ignite the mixture of the preheating fuel and the oxidant, thereby generating a preheating flame.
- the preheating flame is positioned between the preheating fuel distributor 106 and the perforated flame holder 102.
- the preheating flame preheats the perforated flame holder 102 until the perforated flame holder 102 reaches the operating temperature.
- the combustion system 100 transitions to the standard operating state.
- the combustion system 100 utilizes the main fuel distributor 1 10, the main fuel source 1 12, and the oxidant source 104 to support a combustion reaction at least partially within the perforated flame holder 102 during a standard operating state.
- the main fuel source 1 12 supplies a main fuel to the main fuel distributor 1 10.
- the main fuel distributor 1 10 outputs the main fuel with a trajectory to be received by the perforated flame holder 102.
- the main fuel and the oxidant mix as the main fuel travels toward the perforated flame holder 102.
- the perforated flame holder 102 receives the mixture of the main fuel and the oxidant within the perforated flame holder 102. Because the perforated flame holder 102 has been heated to the operating
- the perforated flame holder 102 supports a combustion reaction of the main fuel and the oxidant at least partially within the perforated flame holder 102.
- the oxidant source 104 includes multiple sources of oxidant.
- the oxidant source 104 may supply oxidant from all sources of oxidant, e.g., through slots in a barrel register and from a common upstream supply.
- the barrel register can be closed so that all oxidant comes from upstream the slots of the barrel register.
- the oxidant source 104 includes dampers whose positions can be adjusted to direct all of the flow of the oxidant closer in proximity to a location of the main fuel distributors during the standard operating state and during transition to the standard operating state.
- the dampers position of the dampers can be adjusted to enable flow of the oxidant proximal to the preheating fuel distributors 106.
- various conditions can arise during the preheating state, the standard operating state, and the transition between the preheating state and the standard operating state.
- the conditions in the combustion system 100 can indicate that the preheating state is progressing normally, that the time to transition to the standard operating state has arrived, or that the combustion system 100 is operating as expected in the standard operating state.
- the conditions can indicate a problem with one or more components, processes, or operations of combustion system 100.
- the conditions within the combustion system 100 can indicate that one or more parameters of the combustion system 100 should be adjusted in order to bring operations to a desired state, that the combustion system 100 should revert from a standard operating state to the preheating state, or that the combustion system 100 should shut down.
- the combustion system 100 utilizes a sensor array 1 14, a controller 1 16, actuators 1 18, and a display 120 in order to monitor and address the conditions within the combustion system 100.
- the sensor array 1 14 includes multiple sensors configured to sense various parameters of the combustion system 100.
- the sensors of the sensor array 1 14 can provide sensor signals to the controller 1 16.
- the controller 1 16 receives the sensor signals, identifies conditions within the combustion system 100, and controls the actuators 1 18 to adjust the conditions within the combustion system 100.
- the sensor signals can indicate that the preheating state is progressing normally, that the time to transition to the standard operating state has arrived, or that the combustion system is operating as expected in the standard operating state.
- the sensor signals can also indicate a problem with the conditions or components of the combustion system 100.
- the controller 1 16 can adjust the components or conditions of the combustion system 100 in response to the sensor signals by controlling the actuators 1 18 to physically adjust components or parameters of the combustion system 100.
- the display 120 can indicate the present conditions within the combustion system 100 in accordance with the sensor signals, can indicate that the controller 1 16 is taking one or more corrective actions, or can indicate that an operator of the combustion system 100 should operate one or more manual controls 123 in order to adjust conditions within the combustion system 100.
- the sensor array 1 14 includes a preheating flame sensor 124.
- the preheating flame sensor 124 senses parameters relating to the preheating flame during the preheating state of the combustion system 100.
- the preheating flame sensor 124 provides sensor signals to the controller 1 16 indicating the conditions of the preheating flame. Based on the sensor signals provided by the preheating flame sensor 124, the controller 1 16 can adjust parameters of the combustion system 100.
- the preheating flame sensor 124 detects whether the preheating flame is present during the preheating state.
- the controller 1 16 controls one or more of the actuators 1 18 to cause the oxidant source 104 to output the oxidant into the furnace volume.
- the controller 1 16 can also control the actuators 1 18 to operate a valve or other mechanism enabling the preheating fuel source 108 to supply the preheating fuel to the preheating fuel distributor 106.
- the controller 1 16 can then cause an ignition mechanism, such as a sparker, to ignite the preheating fuel and the oxidant, thereby initiating the preheating flame.
- the preheating flame sensor 124 senses whether the preheating flame is present during the preheating state.
- the preheating flame sensor 124 provides sensor signals to the controller 1 16 indicating whether or not the preheating flame is present. If the sensor signals indicate that the preheating flame is not present, the controller 1 16 can take action such as causing the igniter to generate additional sparks in order to ignite the preheating fuel and the oxidant. If the preheating flame sensor 124 indicates that the preheating flame is still not present, then the controller 1 16 can control the actuators 1 18 to attempt to cause the oxidant source 104 to supply oxidant or to attempt to cause the preheating fuel source 108 to supply the preheating fuel to the preheating fuel distributor 106. This can be followed by causing the igniter to generate additional sparks.
- the controller 1 16 can indicate that a system fault has occurred that requires that the combustion system 100 be shut down until an operator can inspect the oxidant source 104, the preheating fuel source 108, preheating fuel distributor 106, the valves connecting the preheating fuel distributor 106 and the preheating fuel source 108, and the actuators 1 18 in order to identify and correct any faulty conditions with these components. The operator can then inspect the various components and correct any issues.
- the preheating flame sensor 124 may sense the position of the preheating flame.
- the preheating flame may be present and may not be in the desired position.
- the sensor signal can indicate that the preheating flame is too close to the perforated flame holder 102 or too far from the perforated flame holder 102, i.e., too close to the preheating fuel distributor 106.
- the controller 1 16 can adjust the flow of oxidant into the furnace volume by increasing or decreasing the flow of oxidant into the furnace volume.
- the controller 1 16 can adjust the flow of the preheating fuel into the furnace volume by increasing or decreasing the flow rate of the preheating fuel, or by increasing or decreasing the velocity of the preheating fuel. By adjusting the flow of the oxidant and the preheating fuel, the controller 1 16 can adjust the position of the preheating flame relative to the perforated flame holder 102.
- the preheating flame sensor 124 can indicate a temperature of the preheating flame.
- the preheating flame may be
- the sensor signals can inform the controller 1 16 of the temperature of the preheating flame.
- the controller 1 16 can adjust the parameters of the flow of oxidant and preheating fuel in order to adjust the temperature of the preheating flame during the preheating state.
- the preheating flame sensor 124 can include multiple sensors.
- the preheating flame sensor 124 can include one or more of a flame scanner, a flame rod, a temperature sensor, an image capture device, a flame rod or other kinds of sensors for detecting the presence and parameters of the preheating flame.
- the sensor array 1 14 can include a perforated flame holder sensor 122.
- the perforated flame holder sensor 122 can monitor the parameters of the perforated flame holder 102.
- the perforated flame holder sensor 122 senses parameters of the perforated flame holder 102 during the preheating state entering the standard operating state.
- the perforated flame holder sensor 122 generates sensor signals and provides them to the controller 1 16.
- the controller 1 16 receives the sensor signals from the perforated flame holder sensor 122 and can take action to adjust the parameters of the combustion system 100 based on the conditions of the perforated flame holder 102.
- the perforated flame holder sensor 122 includes a temperature sensor configured to sense the temperature of the perforated flame holder 102 during the preheating state.
- the combustion system 100 supports a preheating flame positioned to heat the perforated flame holder 102 to the operating temperature.
- the perforated flame holder sensor 122 monitors the temperature of the perforated flame holder 102. If the sensor signal indicates that the perforated flame holder 102 has not yet reached the operating temperature, then the controller 1 16 keeps the combustion system 100 in the preheating state, thereby causing the preheating flame to continue to heat and increase the temperature of the perforated flame holder 102. If the sensor signals indicate that the perforated flame holder 102 has reached the operating temperature, then the controller 1 16 can cause the combustion system 100 to transition to the standard operating state.
- the controller 1 16 causes the combustion system
- the controller 1 16 can remove the preheating flame by causing the actuators 1 18 to stop the preheating fuel source 108 from supplying the preheating fuel to the preheating fuel distributor 106.
- the controller 1 16 can cause the preheating fuel source 108 to stop providing the preheating fuel to the preheating fuel distributor 106 by closing one or more valves that connect the preheating fuel source 108 to the preheating fuel distributor 106. When the preheating fuel distributor 106 no longer outputs the preheating fuel, the preheating flame will be extinguished.
- the controller 1 16 continues the transition from the preheating state to the standard operating state by causing the main fuel source 1 12 to supply the main fuel to the main fuel distributor 1 10 by controlling the actuators 1 18 to open one or more valves that enable the flow of fuel from the main fuel source 1 12 to the main fuel distributor 1 10.
- the main fuel distributor 1 10 outputs the main fuel into the furnace volume.
- the oxidant source 104 continues to output oxidant into the furnace volume during the transition to the standard operating state.
- the main fuel and the oxidant mix as they travel toward the perforated flame holder 102.
- the perforated flame holder 102 receives the mixture of the main fuel and the oxidant.
- the perforated flame holder 102 Because the perforated flame holder 102 has reached the operating temperature, the perforated flame holder 102 outputs heat sufficient to ignite the mixture of the main fuel and the oxidant at the perforated flame holder 102. In the standard operating state, the perforated flame holder 102 supports a stable combustion reaction of the main fuel and the oxidant at least partially within the perforated flame holder 102. In this way, the controller 1 16 can cause the transition of the combustion system 100 from the preheating state to the standard operating state responsive to the sensor signals from the perforated flame holder sensor 122.
- the perforated flame holder sensor 122 continues to monitor the perforated flame holder 102 in the standard operating state and to output sensor signals to the controller 1 16.
- the perforated flame holder sensor 122 can detect the presence or absence of the combustion reaction within and adjacent to the perforated flame holder 102. If the perforated flame holder sensor 122 indicates that the combustion reaction of the main fuel and the oxidant is not present at the perforated flame holder 102, then the controller 1 16 can take corrective action.
- the controller 1 16 can cause the actuators 1 18 to adjust or reopen the valves that enable the flow of the main fuel from the main fuel source 1 12 to the main fuel distributor 1 10.
- the controller 1 16 can output a message on the display 120 indicating to an operator to check whether the main fuel source 1 12 is supplying the main fuel to the main fuel distributor 1 10 and to take corrective action, if necessary, by operating the manual controls 123. If, after the controller 1 16 has taken corrective actions, the perforated flame holder sensor 122 indicates the absence of a combustion reaction of the main fuel and the oxidant, the controller 1 16 can cause the combustion system 100 to enter a fault state in which all fuel sources shut down so that neither the main fuel nor the preheating fuel is output into the furnace volume.
- the perforated flame holder sensor 122 can indicate that the combustion reaction of the fuel and oxidant is localized below the perforated flame holder 102 or in an otherwise undesirable location.
- the controller 1 16 can take actions such as adjusting the flow of the main fuel, adjusting the output of oxidant, or adjusting of the parameters of the
- the controller 1 16 can output messages on the display 120 indicating to an operator of the combustion system 100 that the combustion reaction is not properly held by the perforated flame holder 102 and that the operator should take corrective action.
- the perforated flame holder sensor 122 can indicate that the temperature of the perforated flame holder 102 has fallen below the operating temperature.
- the controller 1 16 can cause the combustion system 100 to reenter the preheating state.
- the combustion system 100 may include a heater separate from the preheating fuel distributor 106 and the preheating fuel source 108. The heater can be positioned adjacent to or on the perforated flame holder 102. If the perforated flame holder sensor 122 indicates that the temperature of the perforated flame holder 102 is below the operating temperature, the controller 1 16 can activate the heater in order to heat the perforated flame holder 102 to the operating temperature. The controller 1 16 can cause the main fuel distributor 1 10 to again output the main fuel in order to reenter the standard operating state in which the perforated flame holder 102 sustains a
- the perforated flame holder sensor 122 includes one or more of a flame scanner, a flame rod, a temperature sensor, a visible light sensor, an infrared light sensor, an ultraviolet light sensor, an image capture device that captures images in one or more of the visible light spectrum, the infrared light spectrum, or the ultraviolet light spectrum, or any other type of sensor that can detect parameters of a combustion reaction.
- the perforated flame holder sensor 122 can include multiple sensors of the same type.
- the perforated flame holder sensor 122 can include multiple sensors of different types, such as those set forth above.
- FIG. 1 indicates a single perforated flame holder sensor 122, the perforated flame holder sensor 122 can include multiple individual sensors of different kinds or of the same kind.
- the controller 1 16 can stop the flow of all fuel into the furnace volume.
- the preheating flame sensor 124 includes one or more of a flame scanner, a flame rod, a temperature sensor, a visible light sensor, an infrared light sensor, an ultraviolet light sensor, an image capture device that captures images in one or more of the visible light spectrum, the infrared light spectrum, or the ultraviolet light spectrum, or any other type of sensor that can detect parameters of a combustion reaction.
- the preheating flame sensor 124 can include multiple sensors of the same type.
- the preheating flame sensor 124 can include multiple sensors of different types, such as those set forth above. Thus, while FIG. 1 indicates a single preheating flame sensor 124, the preheating flame sensor 124 can include multiple individual sensors of different kinds or of the same kind.
- the sensor array 1 14 includes sensors other than the perforated flame holder sensor 122 and the preheating flame sensor 124.
- the sensor array 1 14 can include one or more of a bridge wall temperature sensor, a CO monitor, an NOx monitor, an O2 monitor, a process monitor, a draft pressure sensor, a dynamic pressure sensor, a pressure differential sensor, or other kinds of sensors. Some of the sensors can be included in the perforated flame holder sensor 122 or the preheating flame sensor 124. All the sensors of the sensor array 1 14 provide control signals to the controller 1 16. The controller 1 16 can take actions to adjust conditions in the combustion system 100 responsive to the sensor signals from the various sensors of the sensor array 1 14.
- the controller 1 16 includes a non-transitory computer readable medium and one or more processors.
- the non-transitory computer readable medium can include one or more memories and store instructions encoded in software for controlling the combustion system 100.
- the one or more processors are configured to execute the instructions.
- the instructions can include data related to the various operating conditions of the combustion system 100.
- the instructions can include data related to both faulty or undesirable operating conditions and proper or desirable operating conditions.
- the instructions can include actions to be taken by the controller 1 16 responsive to the sensor signals received by the controller 1 16.
- the actions can include adjusting conditions of the combustion system 100 by causing the actuators 1 18 to adjust, activate, or deactivate various components of the combustion system 100.
- the actions taken by the controller 1 16 can also include outputting messages to a display 120.
- the messages can include data indicating the current conditions of the
- the messages can also include data prompting an operator of the combustion system 100 to take various actions in order to maintain or adjust the conditions of the combustion system 100.
- the messages can include prompts to approve an action proposed by the controller 1 16 to adjust or maintain conditions in the combustion system 100.
- the controller 1 16 can also output data via wired or wireless connections to one or more other computing systems.
- the data can include data related to current conditions of the combustion system 100, data related to actions taken by the controller 1 16, data related to actions proposed by the controller 1 16, or prompts to an operator of the combustion system 100 to take actions or to approve proposed actions.
- the software instructions include one or more algorithms, state diagrams, decision trees, or other instructions by which the controller 1 16 makes decisions to adjust the parameters of the combustion system 100.
- the controller 1 16 can also include a state machine that determines actions to be taken by the controller 1 16 responsive to the sensor signals.
- the actuators 1 18 include mechanisms that can control, adjust, or otherwise affect physical components of the combustion system 100.
- the actuators 1 18 can include motors, motivators, electrical switches, electrical connectors, electrical transmitters, or other types of mechanisms that can physically affect or manipulate components of the combustion system 100.
- the actuators 1 18 can include motors or switches for physically opening, closing, or otherwise adjusting valves that control the flow of fuel or oxidant into the furnace volume.
- the actuators 1 18 can include mechanisms that control the movements of a stack damper.
- the actuators 1 18 can include mechanisms that activate an igniter to ignite the preheating flame or the main combustion reaction.
- the actuators 1 18 can include mechanisms that adjust the mixture of fuels included in the preheating fuel or the main fuel by increasing or decreasing the concentration of various components of the preheating fuel or the main fuel.
- the actuators 1 18 can include mechanisms for adjusting, activating, or the activating the oxidant source 104.
- the actuators 1 18 can include other kinds of mechanisms for physically manipulating components of the combustion system 100 other than those set forth above. These other kinds of mechanisms can also include mechanisms for controlling components of the combustion system 100 not shown in FIG. 1 or expressly described herein.
- the manual controls 123 enable an operator of the combustion system 100 to physically manipulate components of the
- the manual controls 123 can include switches, buttons, dials, levers, keypads, touchscreens, keyboards, or other types of mechanisms that can enable an operator to manipulate the components of the combustion system 100.
- the manual controls 123 can include manual devices for opening and closing valves.
- the manual controls 123 can include the valves themselves.
- the manual controls 123 can enable an operator to activate, deactivate, or adjust the oxidant source 104, the main fuel source 1 12, the preheating fuel source 108, the main fuel distributor 1 10, the preheating fuel distributor 106, the igniter, the heater, the stack damper, or any other components of the combustion system 100.
- the manual controls 123 can control the actuators
- the manual controls 123 can control some or all of the same actuators 1 18 that can be controlled by the controller 1 16.
- the manual controls 123 can also control actuators 1 18 that cannot be controlled by the controller 1 16.
- the manual controls 123 include some or all of the actuators 1 18.
- the manual controls 123 enable an operator to shut down the combustion system 100 entirely or to override actions taken by the controller 1 16.
- FIG. 2 is a simplified diagram of a burner system 200 including a perforated flame holder 102 configured to hold a combustion reaction, according to an embodiment.
- a perforated flame holder 102 configured to hold a combustion reaction
- the terms perforated flame holder, perforated reaction holder, porous flame holder, porous reaction holder, duplex, and duplex tile shall be considered synonymous unless further definition is provided. Experiments performed by the inventors have shown that perforated flame holders 102 described herein can support very clean combustion.
- the burner system 200 includes a fuel and oxidant source 202 disposed to output fuel and oxidant into a combustion volume 204 to form a fuel and oxidant mixture 206.
- fuel and oxidant mixture and fuel stream may be used interchangeably and considered synonymous depending on the context, unless further definition is provided.
- combustion volume, combustion chamber, furnace volume, and the like shall be considered synonymous unless further definition is provided.
- the perforated flame holder 102 is disposed in the combustion volume 204 and positioned to receive the fuel and oxidant mixture 206.
- FIG. 3 is a side sectional diagram 300 of a portion of the perforated flame holder 102 of FIGS. 1 and 2, according to an embodiment.
- the perforated flame holder 102 includes a perforated flame holder body 208 defining a plurality of perforations 210 aligned to receive the fuel and oxidant mixture 206 from the fuel and oxidant source 202.
- the terms perforation, pore, aperture, elongated aperture, and the like, in the context of the perforated flame holder 102 shall be considered synonymous unless further definition is provided.
- the perforations 210 are configured to collectively hold a combustion reaction 302 supported by the fuel and oxidant mixture 206.
- the fuel can include hydrogen, a hydrocarbon gas, a vaporized hydrocarbon liquid, an atomized hydrocarbon liquid, or a powdered or pulverized solid.
- the fuel can be a single species or can include a mixture of gas(es), vapor(s), atomized liquid(s), and/or pulverized solid(s).
- the fuel in a process heater application the fuel can include fuel gas or byproducts from the process that include carbon monoxide (CO), hydrogen (H2), and methane (CH4).
- the fuel can include natural gas (mostly CH 4 ) or propane (C3H8).
- the fuel can include #2 fuel oil or #6 fuel oil. Dual fuel applications and flexible fuel applications are similarly contemplated by the inventors.
- the oxidant can include oxygen carried by air, flue gas, and/or can include another oxidant, either pure or carried by a carrier gas.
- the terms oxidant and oxidizer shall be considered synonymous herein.
- the perforated flame holder body 208 can be bounded by an input face 212 disposed to receive the fuel and oxidant mixture 206, an output face 214 facing away from the fuel and oxidant source 202, and a peripheral surface 216 defining a lateral extent of the perforated flame holder 102.
- the plurality of perforations 210 which are defined by the perforated flame holder body 208 extend from the input face 212 to the output face 214.
- the plurality of perforations 210 can receive the fuel and oxidant mixture 206 at the input face 212.
- the fuel and oxidant mixture 206 can then combust in or near the plurality of perforations 210 and combustion products can exit the plurality of perforations 210 at or near the output face 214.
- the perforated flame holder 102 is configured to hold a majority of the combustion reaction 302 within the perforations 210.
- more than half the molecules of fuel output into the combustion volume 204 by the fuel and oxidant source 202 may be converted to combustion products between the input face 212 and the output face 214 of the perforated flame holder 102.
- more than half of the heat or thermal energy output by the combustion reaction 302 may be output between the input face 212 and the output face 214 of the perforated flame holder 102.
- the terms heat, heat energy, and thermal energy shall be considered synonymous unless further definition is provided.
- heat energy and thermal energy refer generally to the released chemical energy initially held by reactants during the combustion reaction 302.
- heat, heat energy and thermal energy correspond to a detectable temperature rise undergone by real bodies characterized by heat capacities.
- the perforations 210 can be configured to collectively hold at least 80% of the combustion reaction 302 between the input face 212 and the output face 214 of the perforated flame holder 102.
- the inventors produced a combustion reaction 302 that was apparently wholly contained in the perforations 210 between the input face 212 and the output face 214 of the perforated flame holder 102.
- the perforated flame holder 102 can support combustion between the input face 212 and output face 214 when combustion is "time-averaged.” For example, during transients, such as before the perforated flame holder 102 is fully heated, or if too high a (cooling) load is placed on the system, the combustion may travel somewhat downstream from the output face 214 of the perforated flame holder 102. Alternatively, if the cooling load is relatively low and/or the furnace temperature reaches a high level, the combustion may travel somewhat upstream of the input face 212 of the perforated flame holder 102.
- Such transient huffing or flashback is generally short in duration such that, on a time-averaged basis, a majority of combustion occurs within the perforations 210 of the perforated flame holder 102, between the input face 212 and the output face 214.
- the inventors have noted apparent combustion occurring downstream from the output face 214 of the perforated flame holder 102, but still a majority of combustion occurred within the perforated flame holder 102 as evidenced by continued visible glow from the perforated flame holder 102 that was observed.
- the perforated flame holder 102 can be configured to receive heat from the combustion reaction 302 and output a portion of the received heat as thermal radiation 304 to heat-receiving structures (e.g., furnace walls and/or radiant section working fluid tubes) in or adjacent to the combustion volume 204.
- heat-receiving structures e.g., furnace walls and/or radiant section working fluid tubes
- terms such as radiation, thermal radiation, radiant heat, heat radiation, etc. are to be construed as being substantially synonymous, unless further definition is provided. Specifically, such terms refer to blackbody-type radiation of electromagnetic energy, primarily at infrared wavelengths, but also at visible wavelengths owing to elevated temperature of the perforated flame holder body 208.
- the perforated flame holder 102 outputs another portion of the received heat to the fuel and oxidant mixture 206 received at the input face 212 of the perforated flame holder 102.
- the perforated flame holder body 208 may receive heat from the combustion reaction 302 at least in heat receiving regions 306 of perforation walls 308.
- the position of the heat receiving regions 306, or at least the position corresponding to a maximum rate of receipt of heat can vary along the length of the perforation walls 308.
- the location of maximum receipt of heat was apparently between 1/3 and 1/2 of the distance from the input face 212 to the output face 214 (i.e., somewhat nearer to the input face 212 than to the output face 214).
- the heat receiving regions 306 may lie nearer to the output face 214 of the perforated flame holder 102 under other conditions. Most probably, there is no clearly defined edge of the heat receiving regions 306 (or for that matter, the heat output regions 310, described below). For ease of understanding, the heat receiving regions 306 and the heat output regions 310 will be described as particular regions 306, 310.
- the perforated flame holder body 208 can be characterized by a heat capacity.
- the perforated flame holder body 208 may hold thermal energy from the combustion reaction 302 in an amount corresponding to the heat capacity multiplied by temperature rise, and transfer the thermal energy from the heat receiving regions 306 to heat output regions 310 of the perforation walls 308.
- the heat output regions 310 are nearer to the input face 212 than are the heat receiving regions 306.
- the perforated flame holder body 208 can transfer heat from the heat receiving regions 306 to the heat output regions 310 via thermal radiation, depicted graphically as 304.
- the perforated flame holder body 208 can transfer heat from the heat receiving regions 306 to the heat output regions 310 via heat conduction along heat conduction paths 312.
- the perforated flame holder 102 may act as a heat source to maintain the combustion reaction 302, even under conditions where a combustion reaction 302 would not be stable when supported from a conventional flame holder.
- the perforated flame holder 102 causes the combustion reaction 302 to begin within thermal boundary layers 314 formed adjacent to walls 308 of the perforations 210.
- combustion is generally understood to include a large number of individual reactions, and since a large portion of combustion energy is released within the perforated flame holder 102, it is apparent that at least a majority of the individual reactions occur within the perforated flame holder 102.
- the flow is split into portions that respectively travel through individual perforations 210.
- the hot perforated flame holder body 208 transfers heat to the fluid, notably within thermal boundary layers 314 that progressively thicken as more and more heat is transferred to the incoming fuel and oxidant mixture 206.
- a combustion temperature e.g., the auto-ignition temperature of the fuel
- the reactants continue to flow while a chemical ignition delay time elapses, over which time the combustion reaction 302 occurs. Accordingly, the combustion reaction 302 is shown as occurring within the thermal boundary layers 314.
- the thermal boundary layers 314 merge at a merger point 316.
- the merger point 316 lies between the input face 212 and output face 214 that define the ends of the perforations 210.
- the combustion reaction 302 outputs more heat to the perforated flame holder body 208 than it receives from the perforated flame holder body 208.
- the heat is received at the heat receiving region 306, is held by the perforated flame holder body 208, and is transported to the heat output region 310 nearer to the input face 212, where the heat is transferred into the cool reactants (and any included diluent) to bring the reactants to the ignition temperature.
- each of the perforations 210 is characterized by a length L defined as a reaction fluid propagation path length between the input face 212 and the output face 214 of the perforated flame holder 102.
- reaction fluid refers to matter that travels through a
- the reaction fluid includes the fuel and oxidant mixture 206 (optionally including nitrogen, flue gas, and/or other "non-reactive" species). Within the combustion reaction region, the reaction fluid may include plasma associated with the combustion reaction 302, molecules of reactants and their constituent parts, any non-reactive species, reaction intermediates (including transition states), and reaction products. Near the output face 214, the reaction fluid may include reaction products and byproducts, non-reactive gas, and excess oxidant.
- the plurality of perforations 210 can be each characterized by a transverse dimension D between opposing perforation walls 308.
- the inventors have found that stable combustion can be maintained in the perforated flame holder 102 if the length L of each perforation 210 is at least four times the transverse dimension D of the perforation 210. In other embodiments, the length L can be greater than six times the transverse dimension D. For example, experiments have been run where L is at least eight, at least twelve, at least sixteen, and at least twenty-four times the transverse dimension D.
- the length L is sufficiently long for thermal boundary layers 314 to form adjacent to the perforation walls 308 in a reaction fluid flowing through the perforations 210 to converge at merger points 316 within the perforations 210 between the input face 212 and the output face 214 of the perforated flame holder 102.
- L/D ratios between 12 and 48 to work well (i.e., produce low NOx, produce low CO, and maintain stable combustion).
- the perforated flame holder body 208 can be configured to convey heat between adjacent perforations 210.
- the heat conveyed between adjacent perforations 210 can be selected to cause heat output from the combustion reaction portion 302 in a first perforation 210 to supply heat to stabilize a combustion reaction portion 302 in an adjacent perforation 210.
- the fuel and oxidant source 202 can further include a fuel nozzle 218, configured to output fuel, and an oxidant source 220 configured to output a fluid including the oxidant.
- the fuel nozzle 218 can be configured to output pure fuel.
- the oxidant source 220 can be configured to output combustion air carrying oxygen, and optionally, flue gas.
- the perforated flame holder 102 can be held by a perforated flame holder support structure 222 configured to hold the perforated flame holder 102 at a dilution distance Dp away from the fuel nozzle 218.
- the fuel nozzle 218 can be configured to emit a fuel jet selected to entrain the oxidant to form the fuel and oxidant mixture 206 as the fuel jet and oxidant travel along a path to the perforated flame holder 102 through the dilution distance Dp between the fuel nozzle 218 and the perforated flame holder 102.
- the oxidant or combustion air source can be configured to entrain the fuel and the fuel and oxidant travel through the dilution distance Dp.
- a flue gas recirculation path 224 can be provided.
- the fuel nozzle 218 can be configured to emit a fuel jet selected to entrain the oxidant and to entrain flue gas as the fuel jet travels through the dilution distance Dp between the fuel nozzle 218 and the input face 212 of the perforated flame holder 102.
- the fuel nozzle 218 can be configured to emit the fuel through one or more fuel orifices 226 having an inside diameter dimension that is referred to as "nozzle diameter.”
- the perforated flame holder support structure 222 can support the perforated flame holder 102 to receive the fuel and oxidant mixture 206 at the distance Dp away from the fuel nozzle 218 greater than 20 times the nozzle diameter.
- the perforated flame holder 102 is disposed to receive the fuel and oxidant mixture 206 at the distance Dp away from the fuel nozzle 218 between 100 times and 1 100 times the nozzle diameter.
- the perforated flame holder support structure 222 is configured to hold the perforated flame holder 102 at a distance about 200 times or more of the nozzle diameter away from the fuel nozzle 218.
- the fuel and oxidant mixture 206 travels about 200 times the nozzle diameter or more, the mixture is sufficiently homogenized to cause the combustion reaction 302 to produce minimal NOx.
- the fuel and oxidant source 202 can alternatively include a premix fuel and oxidant source, according to an embodiment.
- a premix fuel and oxidant source can include a premix chamber (not shown), a fuel nozzle configured to output fuel into the premix chamber, and an oxidant (e.g., combustion air) channel configured to output the oxidant into the premix chamber.
- a flame arrestor can be disposed between the premix fuel and oxidant source and the perforated flame holder 102 and be configured to prevent flame flashback into the premix fuel and oxidant source.
- the oxidant source 220 can include a blower configured to force the oxidant through the fuel and oxidant source 202.
- the perforated flame holder support structure 222 can be configured to support the perforated flame holder 102 from a floor or wall (not shown) of the combustion volume 204, for example. In another embodiment, the perforated flame holder support structure 222 supports the perforated flame holder 102 from the fuel and oxidant source 202. Alternatively, the perforated flame holder support structure 222 can suspend the perforated flame holder 102 from an overhead structure (such as a flue, in the case of an up-fired system). The perforated flame holder support structure 222 can support the perforated flame holder 102 in various orientations and directions.
- the perforated flame holder 102 can include a single perforated flame holder body 208. In another embodiment, the perforated flame holder 102 can include a plurality of adjacent perforated flame holder sections that collectively provide a tiled perforated flame holder 102.
- the perforated flame holder support structure 222 can be configured to support the plurality of perforated flame holder sections.
- the perforated flame holder support structure 222 can include a metal superalloy, a cementatious, and/or ceramic refractory material.
- the plurality of adjacent perforated flame holder sections can be joined with a fiber reinforced refractory cement.
- the perforated flame holder 102 can have a width dimension W between opposite sides of the peripheral surface 216 at least twice a thickness dimension T between the input face 212 and the output face 214. In another embodiment, the perforated flame holder 102 can have a width dimension W between opposite sides of the peripheral surface 216 at least three times, at least six times, or at least nine times the thickness dimension T between the input face 212 and the output face 214 of the perforated flame holder 102.
- the perforated flame holder 102 can have a width dimension W less than a width of the combustion volume 204. This can allow the flue gas recirculation path 224 from above to below the perforated flame holder 102 to lie between the peripheral surface 216 of the perforated flame holder 102 and the combustion volume wall (not shown).
- the perforations 210 can be of various shapes.
- the perforations 210 can include elongated squares, each having a transverse dimension D between opposing sides of the squares.
- the perforations 210 can include elongated hexagons, each having a transverse dimension D between opposing sides of the hexagons.
- the perforations 210 can include hollow cylinders, each having a transverse dimension D corresponding to a diameter of the cylinder.
- the perforations 210 can include truncated cones or truncated pyramids (e.g., frustums), each having a transverse dimension D radially symmetric relative to a length axis that extends from the input face 212 to the output face 214.
- the perforations 210 can each have a lateral dimension D equal to or greater than a quenching distance of the flame based on standard reference conditions.
- the perforations 210 may have lateral dimension D less than a standard reference quenching distance.
- each of the plurality of perforations 210 has a lateral dimension D between 0.05 inch and 1 .0 inch.
- each of the plurality of perforations 210 has a lateral dimension D between 0.1 inch and 0.5 inch.
- the plurality of perforations 210 can each have a lateral dimension D of about 0.2 to 0.4 inch.
- the void fraction of a perforated flame holder 102 is defined as the total volume of all perforations 210 in a section of the perforated flame holder 102 divided by a total volume of the perforated flame holder 102 including perforated flame holder body 208 and perforations 210.
- the perforated flame holder 102 should have a void fraction between 0.10 and 0.90.
- the perforated flame holder 102 can have a void fraction between 0.30 and 0.80.
- the perforated flame holder 102 can have a void fraction of about 0.70. Using a void fraction of about 0.70 was found to be especially effective for producing very low NOx.
- the perforated flame holder 102 can be formed from a fiber reinforced cast refractory material and/or a refractory material such as an aluminum silicate material.
- the perforated flame holder 102 can be formed to include mullite or cordierite.
- the perforated flame holder body 208 can include a metal superalloy such as Inconel or Hastelloy.
- the perforated flame holder body 208 can define a honeycomb. Honeycomb is an industrial term of art that need not strictly refer to a hexagonal cross section and most usually includes cells of square cross section. Honeycombs of other cross sectional areas are also known.
- the perforated flame holder 102 can be formed from VERSAGRID ® ceramic honeycomb, available from Applied Ceramics, Inc. of Doraville, South Carolina.
- the perforations 210 can be parallel to one another and normal to the input and output faces 212, 214. In another embodiment, the perforations 210 can be parallel to one another and formed at an angle relative to the input and output faces 212, 214. In another embodiment, the perforations 210 can be non-parallel to one another. In another embodiment, the perforations 210 can be non-parallel to one another and non-intersecting. In another embodiment, the perforations 210 can be intersecting.
- the perforated flame holder body 208 can be one piece or can be formed from a plurality of sections.
- the perforated flame holder 102 may be formed from reticulated ceramic material.
- reticulated refers to a netlike structure. Reticulated ceramic material is often made by dissolving a slurry into a sponge of specified porosity, allowing the slurry to harden, and burning away the sponge and curing the ceramic.
- the perforated flame holder 102 may be formed from a ceramic material that has been punched, bored or cast to create channels.
- the perforated flame holder 102 can include a plurality of tubes or pipes bundled together.
- the plurality of perforations 210 can include hollow cylinders and can optionally also include interstitial spaces between the bundled tubes.
- the plurality of tubes can include ceramic tubes. Refractory cement can be included between the tubes and configured to adhere the tubes together.
- the plurality of tubes can include metal (e.g., superalloy) tubes.
- the plurality of tubes can be held together by a metal tension member circumferential to the plurality of tubes and arranged to hold the plurality of tubes together.
- the metal tension member can include stainless steel, a superalloy metal wire, and/or a superalloy metal band.
- the perforated flame holder body 208 can alternatively include stacked perforated sheets of material, each sheet having openings that connect with openings of subjacent and superjacent sheets.
- the perforated sheets can include perforated metal sheets, ceramic sheets and/or expanded sheets.
- the perforated flame holder body 208 can include discontinuous packing bodies such that the perforations 210 are formed in the interstitial spaces between the discontinuous packing bodies.
- the discontinuous packing bodies include structured packing shapes.
- the discontinuous packing bodies include random packing shapes.
- the discontinuous packing bodies can include ceramic Raschig ring, ceramic Berl saddles, ceramic Intalox saddles, and/or metal rings or other shapes (e.g., Super Raschig Rings) that may be held together by a metal cage.
- the inventors contemplate various explanations for why burner systems including the perforated flame holder 102 provide such clean combustion.
- the perforated flame holder 102 may act as a heat source to maintain a combustion reaction even under conditions where a combustion reaction would not be stable when supported by a conventional flame holder. This capability can be leveraged to support combustion using a leaner fuel-to-oxidant mixture than is typically feasible.
- an average fuel-to-oxidant ratio of the fuel stream 206 is below a (conventional) lower combustion limit of the fuel component of the fuel stream 206— lower combustion limit defines the lowest concentration of fuel at which a fuel and oxidant mixture 206 will burn when exposed to a momentary ignition source under normal atmospheric pressure and an ambient temperature of 25° C (77° F).
- the perforated flame holder 102 and systems including the perforated flame holder 102 described herein were found to provide substantially complete combustion of CO (single digit ppm down to undetectable, depending on experimental conditions), while supporting low NOx. According to one interpretation, such a performance can be achieved due to a sufficient mixing used to lower peak flame temperatures (among other strategies). Flame temperatures tend to peak under slightly rich conditions, which can be evident in any diffusion flame that is insufficiently mixed. By sufficiently mixing, a homogenous and slightly lean mixture can be achieved prior to combustion. This combination can result in reduced flame temperatures, and thus reduced NOx formation.
- "slightly lean” may refer to 3% O2, i.e., an equivalence ratio of -0.87. Use of even leaner mixtures is possible, but may result in elevated levels of O2.
- perforation walls 308 may act as a heat sink for the combustion fluid. This effect may alternatively or additionally reduce combustion temperatures and lower NOx.
- production of NOx can be reduced if the combustion reaction 302 occurs over a very short duration of time.
- Rapid combustion causes the reactants (including oxygen and entrained nitrogen) to be exposed to NOx-formation temperature for a time too short for NOx formation kinetics to cause significant production of NOx.
- the time required for the reactants to pass through the perforated flame holder 102 is very short compared to a conventional flame.
- the low NOx production associated with perforated flame holder combustion may thus be related to the short duration of time required for the reactants (and entrained nitrogen) to pass through the perforated flame holder 102.
- FIG. 4 is a flow chart showing a method 400 for operating a burner system including the perforated flame holder shown and described herein.
- the perforated flame holder is first heated to a temperature sufficient to maintain combustion of the fuel and oxidant mixture.
- the method 400 begins with step 402, wherein the perforated flame holder is preheated to a start-up
- step 404 the fuel and oxidant are provided to the perforated flame holder and combustion is held by the perforated flame holder.
- step 402 begins with step 406, wherein start-up energy is provided at the perforated flame holder.
- a decision step 408 determines whether the temperature T of the perforated flame holder is at or above the start-up temperature, Ts. As long as the temperature of the perforated flame holder is below its start-up temperature, the method loops between steps 406 and 408 within the preheat step 402. In decision step 408, if the temperature T of at least a predetermined portion of the perforated flame holder is greater than or equal to the start-up temperature, the method 400 proceeds to overall step 404, wherein fuel and oxidant is supplied to and combustion is held by the perforated flame holder.
- Step 404 may be broken down into several discrete steps, at least some of which may occur simultaneously.
- a fuel and oxidant mixture is provided to the perforated flame holder, as shown in step 410.
- the fuel and oxidant may be provided by a fuel and oxidant source that includes a separate fuel nozzle and oxidant (e.g., combustion air) source, for example.
- the fuel and oxidant are output in one or more directions selected to cause the fuel and oxidant mixture to be received by the input face of the perforated flame holder.
- the fuel may entrain the combustion air (or alternatively, the combustion air may dilute the fuel) to provide a fuel and oxidant mixture at the input face of the perforated flame holder at a fuel dilution selected for a stable combustion reaction that can be held within the perforations of the perforated flame holder.
- step 412 the combustion reaction is held by the perforated flame holder.
- heat may be output from the perforated flame holder.
- the heat output from the perforated flame holder may be used to power an industrial process, heat a working fluid, generate electricity, or provide motive power, for example.
- step 416 the presence of combustion may be sensed.
- Various sensing approaches have been used and are contemplated by the inventors. Generally, combustion held by the perforated flame holder is very stable and no unusual sensing requirement is placed on the system.
- Combustion sensing may be performed using an infrared sensor, a video sensor, an ultraviolet sensor, a charged species sensor, thermocouple, thermopile, flame rod, and/or other combustion sensing apparatuses.
- a pilot flame or other ignition source may be provided to cause ignition of the fuel and oxidant mixture in the event combustion is lost at the perforated flame holder.
- the method 400 may exit to step 424, wherein an error procedure is executed.
- the error procedure may include turning off fuel flow, re-executing the preheating step 402, outputting an alarm signal, igniting a stand-by combustion system, or other steps.
- the method 400 proceeds to decision step 420, wherein it is determined if combustion parameters should be changed. If no combustion parameters are to be changed, the method loops (within step 404) back to step 410, and the combustion process continues. If a change in combustion parameters is indicated, the method 400 proceeds to step 422, wherein the combustion parameter change is executed. After changing the combustion parameter(s), the method loops (within step 404) back to step 410, and combustion continues.
- Combustion parameters may be scheduled to be changed, for example, if a change in heat demand is encountered. For example, if less heat is required (e.g., due to decreased electricity demand, decreased motive power requirement, or lower industrial process throughput), the fuel and oxidant flow rate may be decreased in step 422. Conversely, if heat demand is increased, then fuel and oxidant flow may be increased. Additionally, or alternatively, if the combustion system is in a start-up mode, then fuel and oxidant flow may be gradually increased to the perforated flame holder over one or more iterations of the loop within step 404.
- the burner system 200 includes a heater 228 operatively coupled to the perforated flame holder 102. As described in conjunction with FIGS. 3 and 4, the perforated flame holder 102 operates by outputting heat to the incoming fuel and oxidant mixture 206.
- the heater 228 can include a flame holder configured to support a flame disposed to heat the perforated flame holder 102.
- the fuel and oxidant source 202 can include a fuel nozzle 218 configured to emit a fuel stream 206 and an oxidant source 220 configured to output oxidant (e.g., combustion air) adjacent to the fuel stream 206.
- the fuel nozzle 218 and oxidant source 220 can be configured to output the fuel stream 206 to be progressively diluted by the oxidant (e.g., combustion air).
- the perforated flame holder 102 can be disposed to receive a diluted fuel and oxidant mixture 206 that supports a combustion reaction 302 that is stabilized by the perforated flame holder 102 when the perforated flame holder 102 is at an operating temperature.
- a start-up flame holder in contrast, can be configured to support a start-up flame at a location corresponding to a relatively unmixed fuel and oxidant mixture that is stable without stabilization provided by the heated perforated flame holder 102.
- the burner system 200 can further include a controller 230 operatively coupled to the heater 228 and to a data interface 232.
- the controller 230 can be configured to control a start-up flame holder actuator configured to cause the start-up flame holder to hold the start-up flame when the perforated flame holder 102 needs to be pre-heated and to not hold the start-up flame when the perforated flame holder 102 is at an operating temperature (e.g., when T > T s ).
- a start-up flame holder actuator configured to cause the start-up flame holder to hold the start-up flame when the perforated flame holder 102 needs to be pre-heated and to not hold the start-up flame when the perforated flame holder 102 is at an operating temperature (e.g., when T > T s ).
- the start-up flame holder includes a mechanically-actuated bluff body configured to be actuated to intercept the fuel and oxidant mixture 206 to cause heat-recycling and/or stabilizing vortices and thereby hold a start-up flame; or to be actuated to not intercept the fuel and oxidant mixture 206 to cause the fuel and oxidant mixture 206 to proceed to the perforated flame holder 102.
- a fuel control valve, blower, and/or damper may be used to select a fuel and oxidant mixture flow rate that is sufficiently low for a start-up flame to be jet-stabilized; and upon reaching a perforated flame holder 102 operating temperature, the flow rate may be increased to "blow out" the start-up flame.
- the heater 228 may include an electrical power supply operatively coupled to the controller 230 and configured to apply an electrical charge or voltage to the fuel and oxidant mixture 206.
- An electrically conductive start-up flame holder may be selectively coupled to a voltage ground or other voltage selected to attract the electrical charge in the fuel and oxidant mixture 206. The attraction of the electrical charge was found by the inventors to cause a start-up flame to be held by the electrically conductive start-up flame holder.
- the heater 228 may include an electrical resistance heater configured to output heat to the perforated flame holder 102 and/or to the fuel and oxidant mixture 206.
- the electrical resistance heater 228 can be configured to heat up the perforated flame holder 102 to an operating temperature.
- the electrical resistance heater 228 can further include a power supply and a switch operable, under control of the controller 230, to selectively couple the power supply to the electrical resistance heater 228.
- An electrical resistance heater 228 can be formed in various ways.
- the electrical resistance heater 228 can be formed from KANTHAL® wire (available from Sandvik Materials Technology division of Sandvik AB of Hallstahammar, Sweden) threaded through at least a portion of the
- perforations 210 defined by the perforated flame holder body 208.
- the heater 228 can include an inductive heater, a high-energy beam heater (e.g., microwave or laser), a frictional heater, electro-resistive ceramic coatings, or other types of heating technologies.
- a high-energy beam heater e.g., microwave or laser
- a frictional heater e.g., a frictional heater
- electro-resistive ceramic coatings e.g., electro-resistive ceramic coatings, or other types of heating technologies.
- the heater 228 can include an electrical discharge igniter or hot surface igniter configured to output a pulsed ignition to the oxidant and fuel.
- a start-up apparatus can include a pilot flame apparatus disposed to ignite the fuel and oxidant mixture 206 that would otherwise enter the perforated flame holder 102.
- the electrical discharge igniter, hot surface igniter, and/or pilot flame apparatus can be operatively coupled to the controller 230, which can cause the electrical discharge igniter or pilot flame apparatus to maintain combustion of the fuel and oxidant mixture 206 in or upstream from the perforated flame holder 102 before the perforated flame holder 102 is heated sufficiently to maintain combustion.
- the burner system 200 can further include a sensor 234 operatively coupled to the control circuit 230.
- the sensor 234 can include a heat sensor configured to detect infrared radiation or a temperature of the perforated flame holder 102.
- the control circuit 230 can be configured to control the heating apparatus 228 responsive to input from the sensor 234.
- a fuel control valve 236 can be operatively coupled to the controller 230 and configured to control a flow of fuel to the fuel and oxidant source 202.
- an oxidant blower or damper 238 can be operatively coupled to the controller 230 and configured to control flow of the oxidant (or combustion air).
- the sensor 234 can further include a combustion sensor operatively coupled to the control circuit 230, the combustion sensor being configured to detect a temperature, video image, and/or spectral characteristic of a combustion reaction 302 held by the perforated flame holder 102.
- the fuel control valve 236 can be configured to control a flow of fuel from a fuel source to the fuel and oxidant source 202.
- the controller 230 can be configured to control the fuel control valve 236 responsive to input from the combustion sensor 234.
- the controller 230 can be configured to control the fuel control valve 236 and/or oxidant blower or damper 238 to control a preheat flame type of heater 228 to heat the perforated flame holder 102 to an operating temperature.
- the controller 230 can similarly control the fuel control valve 236 and/or the oxidant blower or damper 238 to change the fuel and oxidant mixture 206 flow responsive to a heat demand change received as data via the data interface 232.
- FIG. 5A is a simplified perspective view of a combustion system 500, including another alternative perforated flame holder 102, according to an embodiment.
- the perforated flame holder 102 is a reticulated ceramic perforated flame holder, according to an embodiment.
- FIG. 5B is a simplified side sectional diagram of a portion of the reticulated ceramic perforated flame holder 102 of FIG. 5A, according to an embodiment.
- the perforated flame holder 102 of FIGS. 5A, 5B can be implemented in the various combustion systems described herein, according to an embodiment.
- the perforated flame holder 102 is configured to support a combustion reaction 302 of the fuel and oxidant mixture 206 at least partially within the perforated flame holder 102.
- the perforated flame holder 102 can be configured to support a combustion reaction 302 of the fuel and oxidant mixture 206 upstream, downstream, within, and adjacent to the reticulated ceramic perforated flame holder 102.
- the perforated flame holder body 208 can include reticulated fibers 539.
- the reticulated fibers 539 can define branching perforations 210 that weave around and through the reticulated fibers 539.
- the perforations 210 are formed as passages through the reticulated ceramic fibers 539.
- the reticulated fibers 1239 are formed as a reticulated ceramic foam. According to an embodiment, the reticulated fibers 1239 are formed using a reticulated polymer foam as a template.
- the reticulated fibers 539 can include alumina silicate. According to an embodiment, the reticulated fibers 539 can be formed from extruded mullite or cordierite. According to an embodiment, the reticulated fibers 539 can include Zirconia. According to an embodiment, the reticulated fibers 539 can include silicon carbide.
- reticulated fibers refers to a netlike structure.
- the reticulated fibers 539 are formed from an extruded ceramic material.
- the interaction between the fuel and oxidant mixture 206, the combustion reaction 302, and heat transfer to and from the perforated flame holder body 208 can function similarly to the embodiment shown and described above with respect to FIGS. 2-4.
- One difference in activity is a mixing between perforations 210, because the reticulated fibers 539 form a discontinuous perforated flame holder body 208 that allows flow back and forth between neighboring perforations 210.
- the reticulated fiber network is sufficiently open for downstream reticulated fibers 539 to emit radiation for receipt by upstream reticulated fibers 539 for the purpose of heating the upstream reticulated fibers 539 sufficiently to maintain combustion of a fuel and oxidant mixture 206.
- heat conduction paths 312 between reticulated fibers 539 are reduced due to separation of the reticulated fibers 539. This may cause relatively more heat to be transferred from the heat-receiving region 306 (heat receiving area) to the heat output region 310 (heat output area) of the reticulated fibers 539 via thermal radiation 304.
- individual perforations 210 may extend from an input face 212 to an output face 214 of the perforated flame holder 102.
- Perforations 210 may have varying lengths L. According to an embodiment, because the perforations 210 branch into and out of each other, individual perforations 210 are not clearly defined by a length L.
- the perforated flame holder 102 is configured to support or hold a combustion reaction 302 or a flame at least partially between the input face 212 and the output face 214.
- the input face 212 corresponds to a surface of the perforated flame holder 102 proximal to the fuel nozzle 218 or to a surface that first receives fuel.
- the input face 212 corresponds to an extent of the reticulated fibers 539 proximal to the fuel nozzle 218.
- the output face 214 corresponds to a surface distal to the fuel nozzle 218 or opposite the input face 212.
- the input face 212 corresponds to an extent of the reticulated fibers 539 distal to the fuel nozzle 218 or opposite to the input face 212.
- the formation of boundary layers 314, transfer of heat between the perforated flame holder body 208 and the gases flowing through the perforations 210, a characteristic perforation width dimension D, and the length L can be regarded as related to an average or overall path through the perforated flame holder 102.
- the dimension D can be determined as a root-mean-square of individual Dn values determined at each point along a flow path.
- the length L can be a length that includes length contributed by tortuosity of the flow path, which may be somewhat longer than a straight line distance TRH from the input face 212 to the output face 214 through the perforated flame holder 102.
- the void fraction (expressed as (total perforated flame holder 102 volume - reticulated fiber 539 volume)/total volume)) is about 70%.
- the reticulated ceramic perforated flame holder 102 is a tile about 1 " x 4" x 4". According to an embodiment, the reticulated ceramic perforated flame holder 102 includes about 100 pores per square inch of surface area. Other materials and dimensions can also be used for a reticulated ceramic perforated flame holder 102 in accordance with principles of the present disclosure.
- the reticulated ceramic perforated flame holder 102 can include shapes and dimensions other than those described herein.
- the perforated flame holder 102 can include reticulated ceramic tiles that are larger or smaller than the dimensions set forth above.
- the reticulated ceramic perforated flame holder 102 can include shapes other than generally cuboid shapes.
- the reticulated ceramic perforated flame holder 102 can include multiple reticulated ceramic tiles.
- the multiple reticulated ceramic tiles can be joined together such that each ceramic tile is in direct contact with one or more adjacent reticulated ceramic tiles.
- the multiple reticulated ceramic tiles can collectively form a single perforated flame holder 102.
- each reticulated ceramic tile can be
- FIG. 6 is a block diagram of components of a combustion system 600, according to an embodiment.
- the combustion system 600 includes a controller 1 16, a set of sensors 1 14, a set of actuators 1 18, a display 120, a heater 668, and a control input 670.
- the set of sensors 1 14, the set of actuators 1 18, the control input 670, the display 120, and the heater 668 are communicatively coupled to the controller 1 16 such that the controller 1 16 can send, or receive signals, instructions, or data from the components.
- These components are utilized to monitor, control, and adjust operation of the combustion system 600 with respect to holding a combustion reaction 302 in a perforated flame holder 102 (see FIGS. 1-3, 5A, 5B).
- the set of sensors 1 14 includes a bridgewall temperature sensor 640, a preheating flame scanner 642, a CO monitor 644, a ⁇ monitor 646, an O 2 monitor 648, a dynamic pressure sensor 649, a perforated flame holder flame scanner 650, a pressure differential sensor 651 , a process monitor 652, a camera 653, a pressure sensor 654, and a perforated flame holder temperature sensor 655.
- These sensors monitor various parameters of the combustion system 600 and output sensor signals to the controller 1 16.
- the sensor signals indicate various parameters of the combustion system 600.
- the set of sensors 1 14 can include fewer sensors, more sensors, or different kinds of sensors than those shown in FIG. 6.
- the set of actuators 1 18 include a stack damper actuator 656, a main fuel actuator 658, a preheating fuel actuator 660, an oxidant source actuator 662, a process actuator 664, an igniter actuator 666, and a heater actuator 668.
- the set of actuators 1 18 receive electrical commands and instructions from the controller 1 16.
- the set of actuators 1 18 activate, control, or adjust components of the combustion system 600 responsive to the commands from the controller 1 16. Additionally, or alternatively, the set of actuators 1 18 can be operated manually by an operator of the combustion system 600.
- the display 120 displays messages, data, or other indications from the controller 1 16. An operator or technician of the
- combustion system 600 can receive information via the display 120.
- the controller 1 16 can output messages via the display 120 indicating various parameters of the combustion system 600 as measured by the set of sensors 1 14.
- the controller 1 16 can output messages via the display 120 indicating operations that the controller 1 16 will undertake, such as transitioning from a preheating state to the standard operating state or controlling one or more of the set of actuators 1 18 responsive to the sensor signals.
- the display 120 can also display prompts requesting input from an operator of the combustion system 600 requesting that the operator provide approval or permission to execute one or more proposed actions.
- the controller 1 16 can undertake actions or refrain from action in accordance with the instructions received from the operator.
- control input 670 enables an operator of the combustion system 600 to enter commands to the controller 1 16.
- the control input 670 can include one or more of the keypad, a keyboard, a touchscreen, buttons, switches, a mouse, a trackpad, or any other suitable way for an operator of the combustion system 600 to input data or commands to the controller 1 16.
- the control input 670 can communicate with the controller 1 16 via any suitable data transfer interface.
- the operator when the controller 1 16 outputs a message on the display 120 requesting input from an operator to proceed with a proposed adjustment to the combustion system 600, the operator can include a command to the controller 1 16 via the control input 670 responsive to the message on the display 120.
- the operator can also utilize the control input 670 to override actions taken by the controller 1 16 in controlling the combustion system 600.
- the bridgewall temperature sensor 640 senses the temperature of the furnace bridgewall.
- the temperature of the furnace bridgewall provides an indication of whether a process of the furnace is ready for operation. As the perforated flame holder 102 sustains a combustion reaction 302, the temperature of the bridgewall will increase. When the bridgewall of the furnace has reached a selected threshold temperature, the combustion system 600 can initiate a process.
- the controller 1 16 receives the temperature of the bridgewall from the bridgewall temperature sensor 640 and takes one or more actions based on the temperature of the bridgewall and on one or more algorithms, state machines, or other software instructions implemented by the controller 1 16. In one example, if the sensor signal from the bridgewall temperature sensor 640 indicates that the temperature of the bridgewall is above the threshold temperature, then the controller 1 16 can send the signal to the process actuator 664. The process actuator 664 can activate a process, such as initiating the flow of a working fluid to be heated by the furnace. In one embodiment, if the bridgewall temperature sensor 640 indicates that the temperature of the bridgewall is below the threshold temperature, then the controller 1 16 refrains from activating the process actuator 664.
- the controller 1 16 can take measures to increase the heat output by the perforated flame holder 102 by operating the main fuel actuator 658 to adjust flow of the main fuel, the oxidant source actuator 662 to adjust the flow of oxidant, the stack damper actuator 656 to adjust the stack damper, or any other actuators that can adjust a parameter of the combustion system 600 to increase output from the perforated flame holder 102.
- the controller 1 16 can also cause the process actuator 664 to adjust or stop the process until the temperature of the bridgewall increases beyond a threshold temperature.
- the preheating flame scanner 642 monitors parameters of the preheating flame while the combustion system 600 is in the preheating state.
- the preheating flame scanner 642 can detect whether the preheating flame is present.
- the preheating flame scanner 642 can detect the position of the preheating flame.
- the preheating flame scanner 642 outputs a sensor signal to the controller 1 16 indicating the presence, absence, position, or other parameters of the preheating flame.
- the controller 1 16 when the controller 1 16 receives the sensor signal from the preheating flame scanner 642, the controller 1 16 takes one or more actions based on the parameters of the preheating flame. If the sensor signal from the preheating flame scanner 642 indicates that the preheating flame is not present, then the controller 1 16 can send command signals to the oxidant source actuator 662 to adjust the flow of oxidant, to the preheating fuel actuator 660 to adjust the flow of the preheating fuel, and to the igniter actuator 666 to ignite the preheating flame by generating sparks or in any other suitable way.
- the controller 1 16 can output control signals that cause the preheating fuel actuator 660 to adjust a flow rate of the preheating fuel, or to adjust a fuel mixture of the preheating fuel.
- the controller 1 16 can also issue commands to the oxidant source actuator 662 causing the oxidant source actuator 662 to increase or decrease the flow of oxidant.
- the CO monitor 644 monitors the concentration of CO and flue gases generated by the combustion reaction 302 of the main fuel and the oxidant in the standard operating state.
- the CO monitor 644 outputs sensor signals to the controller 1 16 indicating concentration of CO in the flue gases generated by the combustion reaction 302 held by the perforated flame holder 102.
- the controller 1 16 receives the sensor signals and takes one or more actions based on the CO concentration as indicated by the sensor signals from the CO monitor 644.
- the controller 1 16 may not adjust any parameters of the combustion system 600 in order to maintain the current state of the combustion reaction 302. If the concentration of CO in the flue gas is higher than an acceptable value, then the controller 1 16 can send signals to the main fuel actuator 658, the oxidant source actuator 662, the heater actuator 668, or the stack damper actuator 656 in order to adjust the combustion reaction 302 of the main fuel and the oxidant.
- the controller 1 16 can cause the main fuel actuator 658 to adjust the flow of the main fuel or the mixture of fuels that make up the main fuel in order to cause the combustion reaction 302 of the main fuel and the oxidant to generate less CO.
- the controller 1 16 can also cause the oxidant source actuator 662 to adjust the flow of oxidant into the furnace in order to reduce the concentration of CO in the flue gas.
- the ⁇ monitor 646 senses the concentration of ⁇ in the flue gas generated by the combustion reaction 302 of the main fuel and the oxidant held by the perforated flame holder 102 in the standard operating state.
- the ⁇ monitor 646 outputs a sensor signal to the controller 1 16 indicating the concentration of ⁇ in the flue gas.
- the controller 1 16 can take one or more actions based on the concentration of the ⁇ in the flue gas as indicated by the sensor signal.
- the controller 1 16 can take actions to reduce the concentration of ⁇ in the flue gas.
- the controller 1 16 can control the oxidant source actuator 662 to increase the flow of oxidant from the oxidant source.
- the controller 1 16 controls the main fuel actuator 658 to decrease the flow of fuel or to otherwise adjust parameters of the flow of the main fuel in order to decrease the concentration of ⁇ in the flue gas.
- the O 2 monitor 648 monitors the presence of O 2 in the flue gas.
- the O 2 monitor 648 outputs a sensor signal to the controller 1 16 indicating the concentration of O 2 in the flue gas.
- the controller 1 16 receives the sensor signal from the O 2 monitor 648 and undertakes one or more actions based on the concentration of O 2 in the flue gas.
- the concentration of O 2 in the flue gas fall within a selected range, e.g., greater than or equal to 2% and less than or equal to 5%. If the sensor signal from the O 2 monitor 648 indicates that the concentration of O 2 is below the selected range, then the controller 1 16 can control the oxidant source actuator 662 to increase the flow of oxidant into the furnace. Additionally, or alternatively, the controller 1 16 can increase the concentration of O 2 in the flue gas by decreasing the flow of fuel into the furnace. If the sensor signal from the O 2 monitor 648 indicates that the concentration of O 2 is greater than the selected range, then the controller 1 16 can cause the oxidant source actuator 662 to decrease the flow of fuel into the furnace.
- a selected range e.g., greater than or equal to 2% and less than or equal to 5%.
- the controller 1 16 can cause the main fuel actuator 658 to increase the flow of the main fuel into the furnace in order to decrease the concentration of O 2 in the flue gas. In some cases, a higher than desired concentration of O 2 can be the result of incomplete fuel burn. Thus, the controller 1 16 can control the main fuel actuator 658 to reduce the velocity of the main fuel in order to more
- the dynamic pressure sensor 649 detects changes in pressure with time at one or more locations in the combustion environment.
- the dynamic pressure sensor 649 generates sensor signals indicative of the change in pressure in the furnace over time or of the draft of the oxidant.
- the sensor signals from the dynamic pressure sensor 649 can indicate a slope or derivative of the pressure with respect to time and/or may be converted to frequency domain to detect audible or inaudible noise caused by pressure waves.
- the inventors note that the dynamic pressure sensor 649 produces a signal indicative of stability of a combustion reaction in the perforated flame holder 102. When the combustion reaction is stable, there is relatively constant pressure at the dynamic pressure sensor 649.
- the dynamic pressure sensor 649 produces a signal corresponding to rapid fluctuations in pressure, a condition that has been noted by the inventors to correspond to relatively high audible noise produced by the flowing gas in the furnace.
- the controller 1 16 can undertake one or more actions to adjust the pressure or other combustion parameters responsive to the sensor signal from the dynamic pressure sensor 649.
- the controller 1 16 can increase or decrease the pressure by controlling the oxidant source actuator 662 to adjust the flow of oxidant responsive to the sensor signals provided by the dynamic pressure sensor 649.
- the controller 1 16 can adjust the pressure by causing the stack damper actuator 656 to adjust the stack damper.
- the controller 1 16 can adjust the pressure by causing the main fuel actuator 658 to adjust the flow of the main fuel.
- the controller 1 16 can also undertake other actions to adjust the pressure responsive to sensor signals provided by the dynamic pressure sensor 649.
- the pressure differential sensor 651 detects pressure differentials or differences across two locations or more in the furnace, such as across the perforated flame holder 102.
- the controller 1 16 can undertake one or more actions to adjust the pressure or other combustion parameters responsive to the sensor signal from the pressure differential sensor 651.
- the controller 1 16 can increase or decrease the pressure by controlling the oxidant source actuator 662 to adjust the flow of oxidant.
- the controller 1 16 can adjust the pressure by causing the stack damper actuator 656 to adjust the stack damper.
- the controller 1 16 can adjust the pressure by causing the main fuel actuator 658 to adjust the flow of the main fuel.
- the controller 1 16 can also undertake other actions to adjust the pressure responsive to sensor signals provided by the dynamic pressure sensor 649.
- the perforated flame holder flame scanner 650 monitors parameters of the combustion reaction 302 of the main fuel and the oxidant held by the perforated flame holder 102.
- the perforated flame holder flame scanner 650 outputs a sensor signal to the controller 1 16 indicating the parameters of the combustion reaction 302 held by the perforated flame holder 102 in the standard operating state.
- the perforated flame holder flame scanner 650 can detect whether the combustion reaction 302 of the main fuel and oxidant is present at the perforated flame holder 102. If the sensor signals output by the perforated flame holder flame scanner 650 indicate that the combustion reaction 302 of the main fuel and oxidant is not present, then the controller 1 16 can undertake one or more actions. For example, the controller 1 16 can cause the heater actuator 668 to provide additional heat to the perforated flame holder 102 so that the perforated flame holder 102 is at a sufficient temperature to initiate a combustion reaction 302 of the main fuel and the oxidant.
- the controller 1 16 can cause the combustion system 600 to revert back to the preheating state by controlling the main fuel actuator 658, the preheating fuel actuator 660, the oxidant source actuator 662, and the igniter actuator 666 to cease the flow of the main fuel, to adjust the flow of the oxidant, to initiate a flow of the preheating fuel, and to ignite the preheating flame until the perforated flame holder 102 has reached the threshold temperature.
- the controller 1 16 can control the main fuel actuator 658 to adjust the flow rate, the velocity, the mixture, or other parameters of the main fuel.
- the controller 1 16 can also cause the oxidant source actuator 662 to adjust the flow of the oxidant in order to cause the combustion reaction 302 of the main fuel and the oxidant to be held by the perforated flame holder 102.
- the perforated flame holder flame scanner 650 can indicate how much heat is generated by the combustion of the main fuel and the oxidant. If the sensor signals from the perforated flame holder flame scanner 650 indicate that the combustion reaction 302 of the main fuel and the oxidant is generating too much heat or too little heat, then the controller 1 16 can take one or more actions. For example, the controller 1 16 can adjust the flow or mixture of the main fuel by controlling the main fuel actuator 658. The controller 1 16 can also cause the oxidant source actuator 662 to adjust the flow of oxidant to increase or decrease the temperature of the combustion reaction 302 of the main fuel and the oxidant.
- the process monitor 652 measures parameters of the process, such as the transfer of heat from the combustion reaction 302 of the main fuel and the oxidant to a working fluid.
- the process monitor 652 outputs sensor signals to the controller 1 16 indicating the parameters of the process.
- the controller 1 16 can take one or more actions to adjust
- the controller 1 16 can control the process actuator 664 in order to adjust one or more aspects of the process responsive to the sensor signal from the process monitor 652. Additionally, or alternatively, the controller 1 16 can control one or more other actuators to adjust parameters of the combustion reaction 302 of the main fuel and the oxidant in order to adjust parameters of the process.
- a camera 653 monitors one or more conditions within the furnace and outputs sensor signals indicative of the monitored condition.
- the camera 653 can include a charge coupled device (CCD) camera, a CMOS camera, or other types of cameras.
- the camera 653 can be part of one or more other sensors in the sensor array 1 14.
- the camera 653 can monitor visual parameters of the perforated flame holder 102, the combustion reaction 302 within the perforated flame holder 102, the preheating flame, flashback of the combustion reaction 302, the physical condition of components, actuators, sensors, or other conditions within the furnace.
- the controller 1 16 can take one or more actions in response to the sensor signals from the camera 653.
- the camera 653 can detect UV wavelengths, IR wavelengths, and/or visible light wavelengths.
- the camera 653 can include a video camera or other kinds of cameras.
- the camera 653 can convert the field of view with a phase mask and detect a signal with a planar CCD or a CMOS array, not as an image of the field of view, but as matrix data that can be decoded to focus at a range of focal planes.
- the sensor array 1 14 can include a flashback sensor configured to detect flashback of the combustion reaction 302 from the perforated flame holder 102 towards the main fuel distributors.
- the flashback sensor can be part of one or more other sensors in the sensor array 1 14.
- the flashback sensor can include one or more of a camera, an infrared sensor, a flame rod, a UV sensor, a CCD camera, thermocouples, photo cells, electrodes, or other kinds of devices capable of sensing flashback.
- the controller 1 16 can control the turndown ratio in the furnace response to sensor signals from one or more of the sensors in the sensor array 1 14 or from sensors not shown or described herein.
- the controller 1 16 can control or adjust the turndown ratio by operating one or more actuators 1 18 to adjust parameters of the combustion environment such as fuel flow parameters, oxidant parameters, operating state parameters, or other parameters.
- the combustion system 600 can include multiple perforated flame holders 102.
- the combustion system 600 can include multiple main fuel distributors 1 10, multiple oxidant sources 104, multiple preheating fuel distributors, and multiple other components to operate the multiple perforated flame holders 102.
- the combustion system 600 can include multiple of the various sensors 1 14 to sense the parameters related to the multiple perforated flame holders 102.
- the controller 1 16 can adjust the parameters related to the multiple perforated flame holders 102 in response to the sensor signals from the various sensors 1 14.
- the sensors can control the operations related to the multiple perforated flame holders 102 based on huffing, instability, and turndown as indicated by the sensors of the sensor array 1 14.
- the controller 1 16 can also cease operation of one or more of the perforated flame holders 102 or can select which and how many of the multiple perforated flame holders 102 should be in operation.
- the controller 1 16 can control the set of actuators 1 18 to control, operate, select, or stop operations related to the multiple perforated flame holders 102.
- the combustion system 600 can also be a multi-fuel system that utilizes multiple fuels or kinds of fuel in holding a combustion reaction 302 in one or more perforated flame holders 102.
- the controller 1 16 can control the flow of the multiple fuels, select which fuels to use, or select mixtures or blends of fuel based on the sensor signals from the various sensors of the sensor array 1 14.
- the pressure sensor 654 monitors pressure in the furnace or the draft pressure of the oxidant.
- the process sensor 654 sensor signals and outputs into the controller 1 16 a signal indicative of the pressure in the furnace or of the draft of the oxidant.
- the controller 1 16 can undertake one or more actions to adjust the pressure responsive to the sensor signal from the pressure sensor 654.
- the controller 1 16 can increase or decrease the pressure by controlling the oxidant source actuator 662 to adjust the flow of oxidant.
- the controller 1 16 can adjust the pressure by causing the stack damper actuator 656 to adjust the stack damper.
- the controller 1 16 can adjust the pressure by causing the main fuel actuator 658 to adjust the flow of the main fuel.
- the controller 1 16 can also undertake other actions to adjust the pressure responsive to sensor signals provided by the pressure sensor 654.
- the perforated flame holder temperature sensor 655 monitors the temperature of the perforated flame holder 102.
- the perforated flame holder temperature sensor 655 generates sensor signals indicating the temperature of the perforated flame holder 102 and transmits them to the controller 1 16.
- the controller 1 16 can undertake one or more actions to adjust the temperature of the perforated flame holder 102 based on the sensor signals from the perforated flame holder temperature sensor 655.
- the perforated flame holder temperature sensor 655 monitors the temperature of the perforated flame holder 102 during the preheating state of the combustion system 600.
- the perforated flame holder temperature sensor 655 monitors the temperature of the perforated flame holder 102. If the sensor signal indicates that the temperature of the perforated flame holder 102 is below the threshold temperature or an operating temperature, then the controller 1 16 causes the combustion system 600 to remain in the preheating state in which the preheating flame remains present and continues to heat the perforated flame holder 102.
- the controller 1 16 can control the preheating fuel actuator 660 and the main fuel actuator 658 to transition from the preheating state to the standard operating state by ceasing the flow of the preheating fuel and initiating the flow of the main fuel.
- the perforated flame holder temperature sensor 655 continues to monitor the temperature of the perforated flame holder 102 during the standard operating state. If the sensor signal from the perforated flame holder temperature sensor 655 indicates that the temperature of the perforated flame holder 102 has dropped below the threshold temperature or the operating temperature, then the controller 1 16 can take one or more actions. For example, the controller 1 16 can cause the heater actuator 668 to begin heating the perforated flame holder 102. Additionally, or alternatively, the controller 1 16 can cause the combustion system 600 to revert to the preheating state by ceasing the flow of the main fuel and initiating the flow of the preheating fuel.
- the controller 1 16 automatically controls the various actuators 1 18 responsive to the sensor signals from the set of sensors 1 14 in accordance with one or more sets of software instructions, algorithms, state machines, or other protocols that indicate what actions the controller 1 16 will take based on the values of the sensor signals generated by the set of sensors 1 14. In one embodiment, the controller 1 16 does not automatically control one or more of the actuators 1 18 responsive to the sensor signals. Instead, the controller 1 16 outputs prompts or instructions via the display 120 to an operator indicating that the operator should manually adjust components of the combustion system 600 based on the sensor signals. The controller 1 16 can also prompt an operator to approve actions to be undertaken by the controller 1 16 so that the controller 1 16 can control the various actuators 1 18. The controller 1 16 can use a mixture of automatic controlling actuators 1 18, prompting an operator to control the actuators 1 18, and prompting an operator to approve proposed actions of the controller 1 16.
- FIG. 7 is a flow diagram of a process 700 for operating a combustion system in a preheating state, according to an embodiment.
- the process 700 can be controlled by a controller 1 16 executing process steps in accordance with one or more algorithms, sets of software instructions, or state machines.
- the controller 1 16 can implement a process 700 by utilizing one or more processors to execute instructions stored on a non-transitory computer readable medium.
- the process 700 begins by pre-purging a furnace of the combustion system.
- the pre-purging process includes purging gases, particulates, or debris from the furnace.
- the pre-purging process can include controlling an oxidant source to flow an oxidant through the furnace in order to clear unwanted gases, particulates, and debris from the furnace. Additionally, or alternatively, the pre-purging process can include passing an inert gas into the furnace in order to remove unwanted gases, particulates, and debris from the furnace.
- the process 700 opens the preheating fuel valve in order to initiate a flow of preheating fuel into the furnace. If the process 700 has not yet begun flowing oxidant into the furnace, then the process 700 can control an oxidant source to begin flowing oxidant into the furnace. From step 704, the process 700 proceeds to step 706.
- the process ignites the preheating flame of the preheating fuel and the oxidant.
- the process may ignite the preheating flame by generating a spark.
- the process may ignite the preheating flame by generating a gliding arc.
- the process may ignite the preheating flame by controlling a pilot burner, such as by deflecting or not deflecting the pilot flame, to ignite the preheating fuel.
- the process may ignite the
- preheating flame by dissipating current through a hot surface ignitor.
- the controller can control an igniter or pilot burner in order to ignite the preheating flame. From step 706, the process 700 proceeds to decision step 708.
- the process determines whether or not the preheating flame is present. If the preheating flame is not present, then the process 700 can revert to step 706 and can attempt again to initiate the preheating flame. If the preheating flame is present at decision step 708, then the process 700 can proceed from decision step 708 to step 710.
- the process 700 preheats the perforated flame holder positioned in the furnace.
- the perforated flame holder is positioned to receive heat from the preheating flame.
- the preheating flame heats the perforated flame holder, causing the temperature of the perforated flame holder to increase.
- the process 700 proceeds to step 712.
- step 712 the process 700 measures the temperature of the perforated flame holder. From step 712, the process proceeds to decision step 714.
- step 714 if the temperature of the perforated flame holder TPFH is less than a threshold or operating temperature TTH, then the process 700 returns to step 710 and continues to preheat the perforated flame holder. At decision step 714, if the temperature of the perforated flame holder is greater than the threshold or operating
- the process 700 proceeds to step 716.
- the threshold temperature TTH is at or above the autoignition temperature of the preheating fuel at the conditions of the system (temperature, humidity, atmospheric pressure).
- the inventors have noted a very slight transient reduction in perforated flame holder temperature TPFH when cold fuel is first introduced to the perforated flame holder.
- the inventors have found it advantageous, therefore, to set the threshold temperature TTH slightly above the preheating fuel autoignition temperature.
- the process 700 transitions from the preheating state to the standard operating state.
- the preheating flame is extinguished and a combustion reaction of the main fuel and oxidant is held by the perforated flame holder.
- FIG. 8 is a flow diagram of a process 800 for operating a combustion system in a standard operating state, according to an embodiment.
- the process 800 can be controlled by a controller 1 16 executing process steps in accordance with one or more algorithms, sets of software instructions, or state machines.
- the controller 1 16 can implement the process 800 by utilizing one or more processors to execute instructions stored on a non-transitory computer readable medium.
- the process 800 transitions from a preheating state to the standard operating state by opening the main fuel valve. With the main fuel valve open, the main fuel is output into the furnace. If the oxidant source is not already supplying oxidant to the furnace, then at step 802 the process 800 can also cause the oxidant source to supply oxidant into the furnace.
- the main fuel and the oxidant travel towards the perforated flame holder and mix together as they travel toward the perforated flame holder.
- the perforated flame holder receives the mixture of the main fuel and the oxidant into the perforations or channels of the perforated flame holder.
- the perforated flame holder Because the perforated flame holder has been heated to the operating temperature or threshold temperature, the perforated flame holder ignites a combustion reaction of the main fuel and the oxidant.
- the perforated flame holder holds a portion of the combustion reaction within the perforated flame holder. Portions of the perforated flame holder can also occur downstream and upstream from the perforated flame holder. From step 802, the process 800 proceeds to step 804.
- the process 800 closes the preheating fuel valve. Closing the preheating fuel valve ceases the flow of the preheating fuel into the furnace, thereby extinguishing the preheating flame.
- the preheating fuel valve can be closed prior to opening the main fuel valve.
- the process 800 proceeds to step 806.
- the process 800 checks measurables or parameters of the combustion system. These measurables can include whether the combustion reaction of the main fuel and oxidant is present, the location of the combustion reaction of the main fuel and oxidant, the
- the process 800 proceeds to decision step 808. At decision step 808, the process 800 determines whether the measured conditions of the combustion system are acceptable. If the measured conditions of the combustion system are not acceptable, the process 800 proceeds to step 810. If the measured conditions of the combustion system are acceptable, the process 800 proceeds to step 812.
- the process 800 takes corrective action to adjust the parameters of the combustion system.
- the corrective actions can include adjusting the flow of the main fuel, adjusting the flow of the oxidant, adjusting the stack damper, activating a heater, adjusting a mixture of the main fuel, shutting down the combustion system, reversing to the preheating state, or other kinds of corrective actions.
- the process 800 proceeds to step 806.
- step 812 the process 800 maintains the present conditions of the perforated flame holder and of the combustion system in general. From step 812, the process 800 can proceed back to step 806 for the measurables to be checked again. Alternatively, if the combustion system has accomplished the desired work, the process 800 can proceed to step 814.
- step 814 the process 800 shuts down the combustion system.
- FIG. 9 is a flow diagram of a process 900 for operating a combustion system in a standard operating state, according to an embodiment.
- the process 900 can be controlled by a controller 1 16 executing process steps in accordance with one or more algorithms, sets of software instructions, or state machines.
- the controller 1 16 can implement a process 900 by utilizing one or more processors to execute instructions stored on a non-transitory computer readable medium.
- the process 900 checks the
- measurables of the combustion system can include whether the combustion reaction of the main fuel and oxidant is present, the location of the combustion reaction of the main fuel and oxidant, the
- step 904 the process 900 determines whether the measured conditions of the combustion system are acceptable. If the measured conditions of the combustion system are not acceptable, the process 900 proceeds to one or more of steps 906, 908, 910, or 912. If the measured conditions of the combustion system are acceptable, the process 900 proceeds to step 914.
- the process 900 adjusts the stack damper responsive to the measured parameters of the combustion system. In one embodiment, at step 908 the process 900 adjusts the oxidant flow responsive to the measured parameters of the combustion system. In one embodiment, at step 910 the process 900 adjusts the main fuel flow
- the process 900 re-transitions to the preheating state, responsive to the measured parameters of the combustion system.
- step 914 the process 900 maintains the present conditions of the perforated flame holder and of the combustion system in general. From step 912, the process 900 can proceed back to step 902 for the measurables to be checked again. Alternatively, if the combustion system has accomplished the desired work, the process 900 can proceed to step 916.
- step 916 the process 900 shuts down the combustion system.
- FIG. 10A is a diagram of the combustion system 1000, according to an embodiment.
- the combustion system 1000 includes a furnace 1071 defining a furnace volume 1073.
- the combustion system 1000 includes a perforated flame holder 102 positioned within the furnace volume 1073.
- the combustion system 1000 includes main fuel distributors 1 10, a preheating fuel distributor 106, an igniter 1077, a preheating flame sensor 124, and the perforated flame holder sensor 122 positioned within the furnace volume 1073.
- the combustion system 1000 includes main fuel distributors 1 10, a preheating fuel distributor 106, an igniter 1077, a preheating flame sensor 124, and the perforated flame holder sensor 122 positioned within the furnace volume 1073.
- combustion system 1000 includes an oxidant source 104, the controller 1 16, actuators 1 18, a display 120, a control input 670, manual controls 123, the main fuel source 1 12, and the preheating fuel source 108.
- the combustion system 1000 includes one or more main fuel valves 1074 controlling a flow of main fuel from the main fuel source 1 12 to the main fuel distributors 1 10.
- the combustion system 1000 includes one or more preheating fuel valves 1076 controlling a flow of the preheating fuel from the preheating fuel source 108 to the preheating fuel distributor 106.
- the combustion system 1000 includes a stack damper 1084 positioned in a flue of the furnace 1071 .
- the combustion system 1000 further includes a bridgewall temperature sensor 640 and a gas composition sensor 1072.
- the controller 1 16 receives sensor signals from the preheating flame sensor 124, the perforated flame holder sensor 122, the bridgewall temperature sensor 640, the gas composition sensor 1072, and the pressure sensor 654.
- the controller 1 16 is coupled to actuators 1 18.
- the various actuators 1 18 are capable of physically adjusting the main fuel valves 1074, the preheating fuel valves 1076, the oxidant source 104, the main fuel distributors 1 10, the preheating fuel distributor 106, and the stack damper 1084.
- the controller 1 16 is configured to control the actuators 1 18 to adjust various parameters of the combustion system 1000.
- the controller 1 16 is configured to output messages, sensor readings, prompts, warnings, alerts, or other types of data on the display 120.
- An operator of the combustion system 1000 can view the data output on the display 120 and can operate the combustion system 1000 responsive to the data output on the display 120.
- the operator of the combustion system 1000 can utilize manual controls 123 to operate the components of the combustion system 1000.
- the manual controls 123 can control the actuators 1 18 to adjust the parameters of the combustion system 1000.
- the manual controls 123 can enable the operator to physically adjust components of the combustion system 1000 separate from the actuators 1 18.
- the control input 670 enables an operator of the combustion system 1000 to input commands or data to the controller 1 16.
- the controller 1 16 can output requests for the user to approve one or more actions proposed by the controller 1 16 responsive to sensor signals provided by the various sensors.
- the operator of the combustion system 1000 can input selections or commands approving or disapproving the proposed actions of the controller 1 16 via the other control inputs 670.
- FIG. 10B is a diagram of the combustion system 1000 of FIG. 10A in the preheating state, according to an embodiment.
- the combustion system 1000 In the preheating state, the combustion system 1000 generates a preheating flame 1075 to preheat the perforated flame holder 102 to an operating temperature.
- the combustion system 1000 can transition to the standard operating state.
- the controller 1 16 controls one or more of the actuators 1 18 to open the preheating fuel valves 1076. With the preheating fuel valves 1076 open, the preheating fuel source 108 supplies the preheating fuel to the preheating fuel distributor 106. The preheating fuel distributor 106 outputs the preheating fuel into the furnace volume 1073. In one embodiment, the preheating fuel distributor 106 includes one or more preheating fuel nozzles each coupled onto the end of a preheating fuel riser. The preheating fuel is output from orifices in the fuel nozzles.
- the controller 1 16 controls one or more of the actuators 1 18 to cause the oxidant source 104 to supply oxidant into the furnace volume 1073.
- the oxidant source 104 supplies the oxidant into the furnace volume 1073.
- the oxidant mixes with the preheating fuel in the furnace volume 1073.
- the oxidant source 104 includes a barrel register.
- the barrel register includes apertures that can be opened to a selected degree in order to draft an oxidant into the furnace volume 1073.
- the actuators 1 18 can control the degree to which the apertures are open, and thus the degree to which the oxidant is drafted into the furnace volume 1073.
- the controller 1 16 controls one or more of the actuators 1 18 to cause the igniter 1077 to ignite the preheating flame 1075 from the preheating fuel and the oxidant.
- the controller 1 16 can cause the igniter 1077 to generate sparks in the presence of the mixed preheating fuel and oxidant.
- the sparks cause ignition of the preheating fuel and the oxidant, thereby initiating the preheating flame 1075.
- the preheating flame sensor 124 monitors the parameters of the preheating flame 1075 and provides sensor signals to the controller 1 16 indicating the sensed parameters of the preheating flame 1075.
- the preheating flame sensor 124 can sense whether the preheating flame 1075 is present.
- the preheating flame sensor 124 can also sense the position of the preheating flame 1075.
- the preheating flame sensor 124 can also sense the temperature of the preheating flame 1075.
- the preheating flame sensor 124 outputs sensor signals to the controller 1 16 indicative of the parameters of the preheating flame 1075.
- the controller 1 16 can adjust the parameters of the preheating flame 1075 responsive to the sensor signals provided by the preheating flame sensor 124. For example, if the preheating flame sensor 124 signals indicate that the preheating flame 1075 is not present, then the controller 1 16 can control one or more of the actuators 1 18 to generate additional sparks from the igniter 1077, to adjust the distribution of the preheating fuel into the furnace volume 1073, or to adjust the flow of the oxidant into the furnace volume 1073. The controller 1 16 can also control the flow of the preheating fuel and the oxidant in order to adjust the position of the preheating flame 1075 responsive to the sensor signals from the preheating flame sensor 124.
- the perforated flame holder sensor 122 measures the temperature of the perforated flame holder 102 during the preheating state and provides sensor signals to the controller 1 16 indicating the temperature of the perforated flame holder 102. If the sensor signals from the perforated flame holder sensor 122 indicates that the temperature of the perforated flame holder 102 is below an operating or threshold temperature, then the controller 1 16 allows the preheating flame 1075 to continue to heat the perforated flame holder 102. If the sensor signals from the perforated flame holder sensor 122 indicate that the temperature of the perforated flame holder 102 is equal to or greater than the operating or threshold temperature, then the controller 1 16 can cause the combustion system 1000 transition to the standard operating state.
- an operator of the combustion system 1000 can activate, operate, or adjust the various components of the combustion system 1000 during the preheating state by operating the manual controls 123.
- the operator can adjust the parameters of the combustion system 1000
- FIG. 10C is a diagram of the combustion system 1000 in the standard operating state, according to an embodiment.
- the combustion system 1000 sustains a combustion reaction 1086 of the main fuel and oxidant at the perforated flame holder 102.
- the combustion system 1000 transitions to the standard operating state by first extinguishing the preheating flame 1075.
- the controller 1 16 extinguishes the preheating flame 1075 by causing one or more of the actuators 1 18 to close the preheating fuel valves 1076, thereby ceasing the flow of the preheating fuel to the preheating fuel distributors 106.
- the preheating fuel distributor 106 ceases to output the preheating fuel, the preheating flame 1075 is extinguished.
- the controller 1 16 causes the combustion system 1000 to enter the standard operating state by causing one or more of the actuators 1 18 to open the main fuel valves 1074, thereby enabling the main fuel to flow from the main fuel source 1 12 to the main fuel distributors 1 10.
- the main fuel distributors 1 10 output the main fuel toward the perforated flame holder 102.
- the controller 1 16 can also cause the oxidant source 104 to output the oxidant into the furnace volume 1073, if the oxidant source 104 is not already outputting the oxidant into the furnace volume 1073.
- the main fuel entrains and mixes with the oxidant as it travels toward the perforated flame holder 102.
- the perforated flame holder 102 Because the perforated flame holder 102 is at the operating temperature, the perforated flame holder 102 ignites and sustains a combustion reaction 1086 of the mixture 206 of the main fuel and the oxidant. In one embodiment, the perforated flame holder 102 holds a portion of the combustion reaction 1086 within the perforated flame holder 102. The perforated flame holder 102 can also sustain a portion of the combustion reaction 1086 upstream and downstream from the perforated flame holder 102.
- the perforated flame holder sensor 122 in the standard operating state, the perforated flame holder sensor 122, the pressure sensor 654, the bridgewall temperature sensor 640, and the gas composition sensor 1072 output sensor signals to the controller 1 16.
- the perforated flame holder sensor 122 monitors parameters of the combustion reaction 1086, including the position,
- the bridgewall temperature sensor 640 senses the temperature of the bridgewall of the furnace 1071 and the pressure sensor 654 senses the pressure within the furnace volume 1073.
- the gas composition sensor 1072 senses the concentration of various gases, such as ⁇ , CO, and O 2 in the flue gases 1082 and exit through the flue of the furnace 1071 .
- the controller 1 16 can cause the actuators 1 18 to adjust the flow of the main fuel, the flow of the oxidant, the orientation of the stack damper 1084, and other components of the combustion system 1000 in order to adjust the parameters of the combustion system 1000.
- the controller 1 16 can control the flow of oxidant and the main fuel, as well as a position of the stack damper 1084 to adjust the concentration of gases in the flue gas 1082, to adjust the location and distribution of the combustion reaction 1086, to adjust the pressure within the furnace volume 1073, or to adjust other parameters of the combustion system 1000.
- FIG. 11 is a diagram of a combustion system 1 100, according to an embodiment.
- the combustion system 1 100 is substantially similar to the combustion system 100 of FIG. 1 , except that the sensor array 1 14 of the combustion system 1 100 includes a flashback sensor 1 123.
- the flashback sensor 1 123 is configured to sense flashback of the combustion reaction held by the perforated flame holder 102 toward the main fuel distributor 1 10 during the standard operating state.
- Flashback is a potentially dangerous condition in which the combustion reaction travels upstream, igniting the fuel stream closer than desired to the main fuel distributor 1 10.
- the flashback sensor 1 123 senses the flashback and transmits sensor signals to the controller 1 16 indicating the presence of flashback. The controller 1 16 can then take one or more actions to stop the flashback condition.
- the controller 1 16 stops the flashback condition by increasing a velocity of the flow of the main fuel from the main fuel distributor 1 10. The increased velocity of the flow of the main fuel inhibits the
- the controller 1 16 can operate one or more of the actuators 1 18 to adjust the flow of the main fuel from the main fuel distributor 1 10 responsive to the sensor signals from the flashback sensor 1 123. Alternatively, the controller 1 16 can output an indication on the display 120 prompting an operator to manually adjust the flow of the main fuel to inhibit flashback.
- the controller 1 16 stops the flashback condition by stopping the flow of the main fuel, thereby bring the combustion system 1 100 out of the standard operating state.
- the controller 1 16 can operate one or more of the actuators 1 18 to stop the flow of the main fuel from the main fuel distributor 1 10 responsive to the sensor signals from the flashback sensor 1 123.
- the controller 1 16 can output an indication on the display 120 prompting an operator to manually stop the flow of the main fuel to inhibit flashback.
- the controller 1 16 can shut down the combustion system 1 100 entirely when flashback occurs.
- the controller 1 16 can take other actions than those described above in order to deal with a flashback condition.
- the flashback sensor 1 123 senses flashback during the preheating state of the combustion system 1 100. In particular, in the preheating state the flashback sensor 1 123 detects flashback of the preheating flame toward the preheating fuel distributor 106.
- the controller 1 16 can respond to the flashback condition in the preheating state by increasing the flow of the preheating fuel, by stopping the flow of the preheating fuel, or in any other suitable manner.
- the flashback sensor 1 123 is positioned to sense flashback between the input face 212 of the perforated flame holder 102 and the main fuel distributor 1 10.
- the flashback sensor 1 123 can have a vertical position between the perforated flame holder 102 and the main fuel distributor 1 10.
- the flashback sensor 1 123 can have a lateral position between the perforated flame holder 102 and the main fuel distributor 1 10.
- the flashback sensor 1 123 can include one or more of a camera, an infrared sensor, a flame rod, a UV sensor, a CCD camera, thermocouples, photo cells, electrodes, or other kinds of devices capable of sensing flashback.
- a camera an infrared sensor
- a flame rod a flame rod
- a UV sensor a UV sensor
- a CCD camera thermocouples
- photo cells electrodes, or other kinds of devices capable of sensing flashback.
- the combustion system in accordance with principles of the present disclosure can include sensors and actuators other than those disclosed herein, other combinations of sensors and actuators, as well as other kinds of actions to be taken by the controller 1 16 responsive to sensor signals. All such other sensors, actuators, combinations, and actions fall within the scope of the present disclosure.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Regulation And Control Of Combustion (AREA)
- Control Of Combustion (AREA)
Abstract
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201762534193P | 2017-07-18 | 2017-07-18 | |
PCT/US2018/042935 WO2019018675A1 (fr) | 2017-07-18 | 2018-07-19 | Système de commande pour brûleur à stabilisateur de flamme perforé |
Publications (1)
Publication Number | Publication Date |
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EP3669121A1 true EP3669121A1 (fr) | 2020-06-24 |
Family
ID=65015586
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP18836068.9A Withdrawn EP3669121A1 (fr) | 2017-07-18 | 2018-07-19 | Système de commande pour brûleur à stabilisateur de flamme perforé |
Country Status (2)
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EP (1) | EP3669121A1 (fr) |
WO (1) | WO2019018675A1 (fr) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11953201B2 (en) | 2013-02-14 | 2024-04-09 | Clearsign Technologies Corporation | Control system and method for a burner with a distal flame holder |
EP3683501A1 (fr) * | 2019-01-17 | 2020-07-22 | ClearSign Technologies Corporation | Système de commande pour un brûleur comportant un porte-flamme perforé |
US11543126B2 (en) | 2019-04-08 | 2023-01-03 | Carrier Corporation | Method and apparatus for mitigating premix burner combustion tone |
CN110596187B (zh) * | 2019-07-03 | 2024-02-20 | 西安科技大学 | 一种模拟车辆热表面引燃油品的实验台 |
DE102021124663A1 (de) * | 2021-09-23 | 2023-03-23 | Vaillant Gmbh | Verfahren zur Überwachung der Zündung einer Flamme eines Brenners |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2015042566A1 (fr) * | 2013-09-23 | 2015-03-26 | Clearsign Combustion Corporation | Régulation de l'ampleur physique d'une réaction de combustion |
US20150226424A1 (en) * | 2013-12-14 | 2015-08-13 | Clearsign Combustion Corporation | Method and apparatus for shaping a flame |
US10024532B2 (en) * | 2013-12-27 | 2018-07-17 | Mitsubishi Heavy Industries, Ltd. | Combustion control device, combustion system, combustion control method and program |
JP6632226B2 (ja) * | 2015-06-12 | 2020-01-22 | 三菱日立パワーシステムズ株式会社 | バーナ、燃焼装置、ボイラ及びバーナの制御方法 |
CN107923613B (zh) * | 2015-09-14 | 2019-09-17 | 克利尔赛恩燃烧公司 | 穿孔火焰保持器的部分转变的火焰启动 |
-
2018
- 2018-07-19 EP EP18836068.9A patent/EP3669121A1/fr not_active Withdrawn
- 2018-07-19 WO PCT/US2018/042935 patent/WO2019018675A1/fr unknown
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WO2019018675A8 (fr) | 2019-11-07 |
WO2019018675A1 (fr) | 2019-01-24 |
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