According to an embodiment, a method for electrically shaping one or more flames includes determining a desired selected flame shape and selectively applying one or more electrical pulses to one or more electrodes or ionizers proximate the flame to drive the flame to the desired or selected shape.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the subject matter presented here.
One or more electrodes 106, 108, and 110 are arranged near or in the combustion volume 103 such that application of voltages to the electrodes forms an electric field across the combustion volume 103 in the vicinity of or through the flame 104 supported therein by the burner nozzle 102. The electrodes 106, 108, and 110 are respectively energized by corresponding electrical leads 112, 114, and 116, which receive voltage signals from a feedback control system 113 including a programmable controller 115, an amplifier 118 and one or more sensors 120.
While the burner nozzle 102 is shown as a simplified hollow cylinder, several alternative embodiments are contemplated. While the burner 102 and the electrodes 106, 108, and 110 are shown in respective forms and geometric relationships, other geometric relationships and forms are contemplated. For example, the electrodes 106, 108, 110 can have shapes other than cylindrical. According to some embodiments, the burner nozzle 102 can be energized to form one of the electrodes. According to some embodiments, a plurality of nozzles can support a plurality of flames in the combustion volume 103.
According to an embodiment, the electrodes 106, 108, 110 can support a second plurality of electric field axes across the combustion volume 103 in the vicinity of or through at least one flame 104. According to the example, one electric field axis can be formed between electrodes 106 and 108. Another electric field axis can be formed between electrodes 108 and 110. Another electric field axis can be formed between electrodes 106 and 110.
According to embodiments, an algorithm can provide a sequence of voltages to the electrodes 106, 108, 110. The algorithm can provide a substantially constant sequence of electric field states or can provide a variable sequence of electric field states, and/or use a variable set of available electrodes, etc.
The flame 104 typically evolves charged species as reaction intermediates or transition states during combustion. A portion of the charges can be depleted or augmented by a voltage applied to a flame-charging electrode to produce a majority charge in the flame 104. For example, one or more of the electrode 106, 108, and 110 can be configured to apply a voltage to the flame 104 or to eject charges for incorporation in the flame 104. For example, holding the burner 102 or other electrode 106, 108, 110 at a positive voltage can attract negatively charged species and remove electrons, leaving a net positive charge in the flame 104. Alternatively, holding the burner 102 or other electrode at a negative voltage can attract positively charged species or eject electrons into the flame 104 or a region adjacent to the flame 104, leaving a net negative charge in the flame 104. Additionally or alternatively, the burner 102 or other electrode 106, 108, 110 can be modulated to positive and negative voltages to periodically withdraw negatively and positively charged species, respectively, from the combustion volume 103. Withdrawing or adding charges to or from the combustion volume 103 can improve the ability of the voltages on the electrodes 106, 108, 110 to impart momentum on hot gases in the combustion volume 103. For example, alternating positive and negative voltages can impart momentum toward a ground surface or point, or to a surface or point modulated antithetically to that of the one or more electrodes 106, 108, 110.
The position of the electrodes and/or the ground points or surfaces can cause the flame 104 to attain a desired shape.
For example, the desired flame shape can include a shape of one or more flames in a burner, boiler, furnace, and/or gas turbine.
According to an embodiment, the input module 202, logic module 204, and drive module 206 can be embodied as computer executable instructions carried by a non-transitory computer readable medium. The computer executable instructions can be configured to cause computer hardware to execute the functions of the input module 202, logic module 204, and drive module 206. In another embodiment, the input module 202, logic module 204, and drive module 206 can be embodied as one or more electronic controller hardware modules configured to execute the functions of the input module 202, logic module 204, and/or drive module 206. In still another embodiment, the input module 202, logic module 204, and drive module 206 can be embodied as a combination of computer executable instructions carried by a non-transitory computer readable medium as one or more electronic controller hardware modules configured to execute the functions of the input module 202, logic module 204, and/or drive module 206.
According to an embodiment, the at least one desired or selected flame shape can include one or more of a flattened flame, a lengthened flame, a narrowed flame, a widened flame, a low emissivity flame, a high emissivity flame, a flame anchored proximate to a fuel source, a flame anchored distal from a fuel source, a lifted flame, a flame supported by a first fuel source, a flame supported partly by the first fuel source and partly by a second fuel source, a flame supported by the second fuel source and not by the first fuel source that had previously supported the flame, a low heat output flame, a high heat output flame, a high reaction rate flame, a low reaction rate flame, a fuel-rich flame, a diluted fuel flame, a flame selected to transfer heat at least primarily to a first heat transfer surface, a flame selected to transfer heat to the first heat transfer surface and to a second heat transfer surface different from the first heat transfer surface, a flame selected to transfer heat at least primarily to the second heat transfer surface and substantially not to the first heat transfer surface that had previously received heat from the flame, a low particulate output flame, a high particulate output flame, a high swirl flame, a low swirl flame, a high majority charge density flame, a low majority charge density flame, and/or a neutrally charged flame. The flame can also be directed away from a surface, for example to minimize flame impingement upon a surface as with process tubes in a process heater, boiler tubes in a boiler, etc. The flame can also be directed toward a surface, for example to maximize flame impingement upon a surface to maximize it as with cookware on a range top, metals processing, etc. The flame can also be directed to change temporally in response to a process load or firing rate, for example to better enable a start-up, operating, or shutdown sequence.
A sequence of desired flame shapes can be included in at least a series of one desired flame shape, according to an embodiment.
Referring to the input module 202, a human interface can be included and operatively coupled to and/or can form a portion of the input module 202. The human interface can be configured to receive a user selection of the at least one desired flame shape. Additionally, the human interface can be configured to present to the user representations of two or more selectable flame shapes.
The input module 202 can be configured to output data corresponding to the desired flame shape and/or to be read by the logic module 204.
In the system 200, one or more sensors can be included and operatively coupled to and/or can form a portion of the input module 202. The one or more sensors can be configured to sense one or more properties of the flame. The one or more sensors can include one or more of an image sensor, a flame image sensor, a video sensor, a flame video sensor, a thermometer, a pyrometer, a thermal radiation sensor, an oxygen sensor, an oxides of nitrogen (NOx) sensor, a carbon monoxide (CO) sensor, a particulate density sensor, a spectrometer, a conductivity sensor, a continuity sensor, a voltage sensor, a species-specific sensor for SO2, Hg, Hg+, or other species of interest, a flame rod, and/or a current sensor. The input module 202 can be configured to output data corresponding to the one or more properties of the flame to and/or to be read by the logic module 204.
According to an embodiment, the logic module 204 can be further configured to receive from the input module 202 the desired flame shape and sensed one or more properties of the flame, compare the sensed one or more properties of the flame to the desired flame shape, and determine or generate data corresponding to a flame shape correction selected to cause the flame to change to the desired flame shape or to a sequence of flame shapes selected to achieve the desired flame shape.
The input module 202 can be configured to receive the sensed one or more properties of the flame, and generate a model of the actual flame from the sensed one or more properties of the flame. The input module 202 can be further configured to compare the model of the actual flame to a model of the desired flame, determine if the difference between the actual flame model and desired flame model is greater than a tolerance, and if the difference is greater than the tolerance, determine or generate data corresponding to a flame shape correction selected to cause the flame to change from a shape corresponding to the actual flame model to a shape corresponding to the desired flame model.
According to an embodiment, the logic module 204 can be configured to read data output by the input module 202, and can algorithmically determine at least a series of one electrical configuration from the data output by the input module 202. Additionally, the logic module 204 can include a look-up table. The logic module 204 can be configured to read data output by the input module 202, address the look-up table with data corresponding to the data output by the input module 202, and read data corresponding to the at least one electrical energy configuration from the look-up table.
The system 200 can include an electrical energy configuration selected by the logic module 204. The selection of the electrical energy configuration by the logic module 204 can correspond to at least a selection of one or more electrodes operatively coupled to the flame. Additionally and/or alternatively, the selection of the electrical energy configuration by the logic module 204 can correspond to at least a selection of one or more of a plurality of electrodes operatively coupled to the flame.
According to an embodiment, the electrical energy configuration selected by the logic module 204 can correspond to at least a selection of one or more ionizers operatively coupled to the flame. Additionally and/or alternatively, the electrical energy configuration selected by the logic module 204 can correspond to at least a selection of one or more of a plurality of ionizers operatively coupled to the flame.
The electrical energy configuration selected by the logic module 204 can correspond to at least a selection of one or more of a plurality of voltage schedules for application to one or more electrodes 208, one or more ionizers 208, or one or more electrodes and/or one or more ionizers 208 operatively coupled to the flame. The plurality of voltage schedules can include one or more of a selected DC voltage, a variable DC voltage, a time-varying voltage, and/or a sequence of voltages.
The electrical energy configuration selected by the logic module 204 can correspond to at least a selection of one or more of a plurality of electrical continuities of one or more electrodes 208 and/or one or more ionizers 208 operatively coupled to the flame. The one or more of a plurality of electrical continuities can include a selection of switching to ground one or more electrode or one or more ionizer control grids.
According to an embodiment, the logic module 204 can be programmable. The programmable logic module 204 can be configured to read computer-executable instructions carried by a non-transitory computer readable medium and execute the instructions.
In the system 200, the logic module 204 can be configured to select one or more electrical pulses or continuity intended to drive a flame holder to maintain a flame location. The logic module 204 can be configured to cause the plurality of drive channels to be energized corresponding to the apparatus parameter.
Referring to the drive module 206, a plurality of drive channels can be operatively coupled to and/or can be included in the drive module 206. The plurality of drive channels can be operatively coupled to one or more electrodes 208, one or more ionizers 208, one or more control grids, or one or more of a combination of one or more electrodes 208, one or more ionizers 208, and/or one or more control grids operatively coupled to the flame.
The plurality of drive channels each can include at least one selected from the group consisting of an insulated gate bipolar transistor (IGBT), a field-effect transistor (FET), a discrete device, a discrete linear device, a nonlinear device, an integrated circuit, and/or a portion of an integrated circuit.
In the system 200, one or more mechanical packages can be included and configured to hold all or a portion of the input interface, logic module 204, and/or drive module 206.
According to an embodiment, a plurality of electrodes disposed proximate to or within the combustion volume can be included. The combustion volume can be configured to support the flame corresponding to at least a series of one desired flame shape responsive to electrical energy applied by the plurality of electrodes.
The one or more of the plurality of electrodes can include a switched ground gate and ion ejector pair.
The one or more of the plurality of electrodes can include a sharp electrode. The sharp electrode can include a serrated electrode.
According to an embodiment, the one or more of the plurality of electrodes can include a switched ion ejector. Additionally, the one or more of the plurality of electrodes can include a charge accumulation surface.
The one or more of the plurality of electrodes and can include a switched continuity control grid configured to float and/or be switched to ground.
According to an embodiment, the system 200 configured for producing a selected flame shape can be configured to maintain a substantially static selected flame shape. Additionally and/or alternatively, the system 200 configured for producing a selected flame shape can be selected for dynamic control of flame shape.
The desired flame shape determined in step 302 can include a selected location of the flame. Selectively applying one or more electrical pulses can include driving a flame holder to maintain the location.
The desired flame shape determined in step 302 can include determining a desired, actual, or future combustion rate. Applying one or more electrical pulses can include selecting parameters to provide a tunable flame holder.
The method 300 can further comprise sensing or receiving an apparatus parameter corresponding to a flame shape. Determining the desired flame shape can include determining the flame shape corresponding to the apparatus parameter. For example, sensing or receiving the apparatus parameter can include receiving a flame width or a flame width adjustment. For example, the apparatus can include a kitchen cooktop. Sensing or receiving the apparatus parameter can include sensing or receiving a heating area corresponding to a pot or pan.
Sensing or receiving the apparatus parameter can include sensing or receiving a temperature distribution. Determining the desired flame shape can include determining the flame shape to control or adjust the temperature distribution.
Determining the desired flame shape in step 302 can include determining the flame length for a residential, commercial, or industrial application. Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape can include driving a streamwise electric field distribution to lengthen or shorten the flame.
Determining the desired flame in step 302 can include determining the flame width for a residential, commercial, or industrial application. Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape can include driving a spanwise electric field distribution to widen or narrow the flame.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include applying a spatially sequenced electric field to provide Lagrangian flame shaping. Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include controlling heat transfer to a hydrogen reformer.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include controlling a flame distribution across a heating tile in a vertical wall reformer.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include providing a rotational injection or lengthening to a flame vortex.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include driving a low pressure drop-flame holder.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include providing end-charging for flame lengthening.
Selectively applying one or more electrical pulses to one or more electrodes proximate the flame to drive the flame to the desired shape in step 304 can include providing a flame shape for a cement kiln.
Referring again to
The electrodes 106, 108 and 110 can be located in different regions of the combustion system 100, for example, and can also exhibit a plurality of shapes, quantities, and sizes according to the desired flame characteristics. A voltage, charge, and or electric fields can be applied with a plurality of waveforms and voltage/current intensities, according to specific flame 104 shape or position.
The sensors 120 can detect a variety of combustion parameters in the flame 104, which can be communicated to the programmable controller 115 to determine the shape and position of the flame 104 within the combustion volume 103. The sensors 120 can include thermal, electric and optical sensors, and the like. In one example, the sensors 120 can include one or more flame rods configured to detect a variety of parameters of the flame. The one or more flame rods can probe the combustion volume 103 to detect the shape of flame 104. According to an embodiment, the controller 115 can adjust the position(s) of the flame rod(s) to probe the combustion volume. Alternatively, the position(s) of the flame rod(s) can be adjusted by a technician using manual or electronic controls.
The programmable controller 115 can calculate the shape and position of the flame 104 according to the sensors 120 input. Subsequently, the programmable controller 115 can send a control signal to the amplifier 118 to energize the electrodes 106, 108, and 110 for a corresponding application of voltage, charge, and or electric field that can adjust shape and position of the flame 104 according to the application.
The flame 104 can exhibit a positive charge as a majority amount of positively charged species in the flame 104 can be generated during combustion. In addition, the burner 102 can be charged to function as a charging electrode that can induce a majority charge to the flame 104. Other separate charging electrodes can be used to induce a majority charge to the flame 104.
According to Coulomb's Law of charge repulsion, if the flame 104 needs to be repelled from the region of the combustion volume 103 such as walls of a steam methane reformer, then the electrodes 106, 108 and 110 can be positioned in that specific region and can be charged with the same polarity of the flame 104. Conversely, if the flame 104 needs to be attracted to the region of combustion volume 103 that integrates electrodes 106, 108 and 110, then electrodes 106, 108 and 110 can be charged with an opposite polarity of flame 104. As such, electrodes 106, 108 and 110 can be placed in different regions of combustion volume 103 and can be positively or negatively charged to adjust flame shape and position according to the application.
In another embodiment, the flame 104 can be charged with a certain polarity by the burner 102 or the electrodes 106, 108 and 110, while the combustion volume 103 can be grounded, forming an equal or opposite polarity with respect to the charge induced in the flame 104. Depending on the charge polarity induced in the flame 104, repulsion or attraction can be generated with respect to combustion volume 103 structure.
According to an embodiment, the feedback control system 113 can modify the shape and position of the flame 104 by applying a corresponding voltage, charge, and/or electric fields through the toric electrode 402.
For this particular application, if the flame 104 needs to be squashed, the toric electrode 402 can be charged with the same polarity of the flame 104. Application of an electric field through the toric electrode 402 with the same polarity of flame 104 can repel flame 104 from the top of combustion volume 103. Conversely, if flame 104 needs to be elongated, toric electrode 402 can be charged with opposite polarity of the flame 104, attracting the flame 104 to the toric electrode 402.
The toric electrode 402 can be located in different regions of the combustion volume 103, and can also exhibit a plurality of quantities, shapes and sizes according to the desired characteristics of the flame 104.
The combustion systems 100, 400 can employ different configurations of the feedback control system 113 to determine flame shape and position, and apply a corresponding voltage, charge, and/or electric field to modify flame characteristics.
According to an embodiment, the programmable controller 115 in the feedback control system 113 can employ one or more current sensors 502 for measuring electric current flowing from the flame 104 and through the electrodes 106, 108 and 110. For example, while the flame 104 is not in contact with the electrodes 106, 108 and 110, the current sensors 502 may not measure electric current from the flame 104 and through the electrodes 106, 108 and 110. If the flame 104 makes contact with one or more electrodes 106, 108 and 110 the electric current flowing from the flame 104 and through the electrodes 106, 108 and 110 can be measured by the current sensors 502. Depending on the specific electrodes 106, 108 and 110 where the current sensors 502 measure electric current, the programmable controller 115 can determine flame shape and position. Consequently, the feedback control system 113 can apply a corresponding voltage, charge, and/or electric fields via the electrodes 106, 108 and 110 for modifying shape and position of the flame 104 as required by the application.
Furthermore, other electric parameters can be measured from the electrodes 106, 108 and 110 for determining shape and position of flame 104. Such electric parameters can include capacitance, voltage gradient and the like.
According to an embodiment, the programmable controller 115 in the feedback control system 113 can be operatively connected to one or more thermocouples 602 for measuring temperature across the flame 104 in the combustion volume 103. Thermocouples 602 can be located in different regions of the combustion volume 103, distributed in an arrangement that can provide an effective reading of temperature changes in the flame 104 or the combustion volume 103.
According to an embodiment, a change in temperature across the flame 104 can be detected by the thermocouples 602 in specific regions of the combustion volume 103. Temperature registered by the thermocouples 602 can be inversely proportional to distance from the flame 104 to specific regions of the combustion volume 103 containing thermocouples 602.
The programmable controller 115 in the feedback control system 113 can analyze temperature readings from the thermocouples 602 and can determine which thermocouples 602 are closer to the flame 104. As a result, shape and position of the flame 104 can be determined using different temperature values or a combination of temperature values measured by all the thermocouples 602 across the combustion volume 103. Consequently, the feedback control system 113 can apply corresponding voltage, charge, and/or electric fields via the electrodes 106, 108 and 110 for modifying shape and position of the flame 104 as required by the application.
According to an alternate embodiment, the thermocouples 602 can be replaced by a plurality of flame rods. The flame rods can be positioned throughout the combustion volume 103 in a similar configuration as the thermocouples 602 shown in
According to an embodiment, the one or more probes 702 can be located in different regions of the refractory 111 in the combustion volume 103, distributed in an arrangement that can provide an effective reading of electric resistivity across refractory 111. The programmable controller 115 in the feedback control system 113 can be operatively connected to the probes 702 for measuring electrical resistance across the refractory 111.
Because of the insulating properties of the refractory 111, there are very few free electrons that hardly allow any current to flow. Electric resistivity of the refractory 111 can decrease when temperature increases. When the flame 104 heats the refractory 111, atoms begin to vibrate, and when heated sufficiently, the atoms can vibrate violently enough to shake some of their captive electrons free, creating free electrons that become carriers of current. As a result, as temperature increases, the electrical resistance of the refractory 111 can decrease.
As the flame 104 approaches certain regions of the refractory 111, temperature in those specific regions can increase, translating into a decrease of resistance that can be measured by the probes 702. The programmable controller 115 in the feedback control system 113 can analyze resistance readings from the probes 702 and can determine which probes 702 are closer to the flame 104. As a result, the shape and position of the flame 104 can be determined using a combination of resistance values measured by the probes 702 distributed across the combustion volume 103. Consequently, the feedback control system 113 can apply a corresponding voltage, charge, and/or electric fields via the electrodes 106, 108 and 110 for modifying shape and position of the flame 104 as required by the application.
Furthermore, other parameters in the refractory 111 can be measured for determining the shape and position of the flame 104. Such parameters can include thermal conductivity, color, and the like.
According to an embodiment, a programmable controller 115 in a feedback control system 113 can employ one or more cameras 802 located in different regions of combustion volume 103 for monitoring flame 104 characteristics.
Cameras 802 can include thermal cameras, conventional cameras, and the like. Cameras 802 can be connected to the programmable controller 115 which can receive information describing flame position and shape in the combustion volume 103. The programmable controller 115 can include algorithms for processing still images received from the cameras 802. Consequently, the feedback control system 113 can apply corresponding voltage, charge, and/or electric fields via electrodes 106, 108 and 110 for modifying the shape and position of the flame 104 as required by the application.
The programmable controller 115 in the feedback control system 113 can be connected to the one or more probes 902, which can be located in a variety of regions across the combustion volume 103, preferably in the exhaust. One or more probes 902 can measure different gas emissions from the flame 104. For example, probes 902 can detect and measure O2, NOx, CO, CO2, and unburned fuel particles, among others.
According to an embodiment, specific shapes and positions of the flame 104 can be correlated to levels of gas emissions generated by flame 104. For example, when electrodes 106, 108 and 110 apply a voltage, charge and/or electric field to flame 104, mixing of air and fuel can improve, resulting in lower CO and O2 emissions, which can be associated with a reduction of flame length. The probes 902 can detect and measure CO and O2 emissions produced by the flame 104, and send this information to the programmable controller 115, which can determine shape and position of flame 104. Subsequently, the feedback control system 113 can apply a corresponding voltage, charge, and/or electric fields via electrodes 106, 108 and 110 for modifying the shape and position of the flame 104 as required by the application.
For example, the process heater 1000 depicted in
Temperature changes across the flame 104 can be detected by the thermocouples 1002 in specific regions of the combustion volume 103. Temperature registered by thermocouples 1002 can be inversely proportional to the distance from the flame 104 to specific regions of the combustion volume 103 containing thermocouples 1002.
The programmable controller 115 in the feedback control system 113 can analyze temperature readings from the thermocouples 1002 and can determine which thermocouples 1002 are closer to the flame 104. As a result, shape and position of the flame 104 can be determined using different temperature values measured by all thermocouples 1002 along the combustion volume 103. For example, if thermocouple 1002 A detects an increase in temperature above normal levels, while thermocouples 1002, B, C, D, and E detect a fall in temperature, then the programmable controller 115 can determine that the flame 104 is elongated and rising over the secondary coil 1006, thus creating a hot spot in the main coil 1004 and the secondary coil 1006. Consequently, the feedback control system 113 can apply corresponding voltage, charge, and/or electric fields via electrodes 106, 108 and 110 for modifying shape and position of the flame 104.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
The present application claims priority benefit from U.S. Provisional Patent Application No. 61/916,188, entitled “METHOD AND APPARATUS FOR SHAPING A FLAME”, filed Dec. 14, 2013, (docket no. 2651-045-02); which, to the extent not inconsistent with the disclosure herein, is incorporated by reference.
Number | Date | Country | |
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61916188 | Dec 2013 | US |