Patent Application
20160138799
Applying a voltage, charge, and/or electric field into a combustion zone may improve the control of flame shape and heat transfer. Moreover, this technique can also be used to optimize the complex chemical reactions that occur during combustion, minimizing harmful emissions, while also maximizing system efficiency.
A combustion system may include one or more electrodes configured to apply a voltage, charge, and/or electric field to a flame. This combustion system may be connected to ancillary equipment such as computers, thermocouples, burning management equipment, and the like. However, the charged flame may contact different regions of the combustion system, discharging high voltages to ancillary equipment and ground. This high voltage discharge may damage ancillary equipment.
A combustion system applies a charge, voltage, and/or electric field to a flame to improve combustion efficiency, emissions, and/or to control flame characteristics. The combustion system is operatively coupled to ancillary burner equipment that supports the application of a charge, voltage, and/or electric field to a flame, support control and measurement of flame characteristics, control pollutant output, control fuel delivery, control air delivery, and/or control flue gas delivery to the flame. To avoid unwanted high voltage discharges through the combustion system that can damage ancillary equipment or operational personnel, electrical isolation or an insulating material is placed between burner and flame, preventing the charging of the combustion chamber through burner, according to an embodiment.
In other embodiments, a safety insulation sub-system is employed as a power supply for ancillary burner equipment. Safety insulation sub-system includes a circuit of batteries that apply power to ancillary equipment.
In another embodiment, safety insulation sub-system includes a motor-generator power conversion system, whereby a motor drives a generator through a non-conductive transfer structure that avoids electrical discharges to ground. Motor can be replaced by another suitable mechanical power supply mechanism such as gasoline engine, steam turbine, compressed air turbine, and the like.
According to various embodiments, retrofitting is enabled since there is no necessity to build new equipment to accomplish effective discharge prevention in a combustion system.
Numerous other aspects, features and advantages of the present invention may be made apparent from the following detailed description taken together with the drawing figures.
Non-limiting embodiments of the present invention are described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. Unless indicated as representing the background art, the figures represent aspects of the invention.
Disclosed herein are embodiments of different approaches to insulate ancillary burner equipment from high voltage discharges. The present disclosure is hereby described in detail with reference to embodiments illustrated in the drawings, which form a part hereof. In the drawings, which are not necessarily to scale or to proportion, similar symbols typically identify similar components, unless context dictates otherwise. Other embodiments may be used and/or other changes may be made without departing from the spirit or scope of the present disclosure. The illustrative embodiments described in the detailed description are not meant to be limiting of the subject matter presented herein.
As used herein, “ancillary burner equipment” may refer to an apparatus employed in a combustion system to support the generation and control of a flame.
As used herein, “electrical insulation material” may refer to a material, which does not conduct electric current.
As used herein, “refractory material” may refer to a material, which may withstand high temperatures and may provide electrical insulation.
The burner 102 can be supported by ancillary equipment 112. In an embodiment, ancillary equipment 112 can include a blower, which can provide air to the burner 102 through an air inlet line 114. The ancillary equipment 112 can be connected to a suitable power supply. Other ancillary equipment 112 can include control equipment, burning management equipment, programmable logic controllers, computers, and/or thermocouples, among others.
A charge, voltage, and/or electric field can be applied to the flame 108 using a variety of electrode configurations, depending on the application. In an embodiment, the electrode 104 can go through a suitable aperture in a region of the combustion chamber 110, thus avoiding direct contact with the combustion chamber 110. The electrode 106 can enter the combustion chamber 110 through the burner 102. The electrode 106 can be coated with an insulation material 116 such as dielectric ceramic, refractory and the like; or may alternatively be supported with a dielectric gap between the electrode 106 and portions of the burner 102 held at a different electrical potential.
The electrode 104 and the electrode 106 can be connected to an amplifier, which can be fed by a power source 118 for charging the electrode 104 and the electrode 106 with AC or DC voltage. In addition, the power source 118 can be managed by a programmable controller.
If the burner 102 is charged by the flame 108, an electrical discharge can flow through the ancillary equipment 112 and ground, damaging ancillary equipment 112 and possibly representing a potential hazard to operational personnel. As a result, an electrical insulator can be placed between the burner 102 and the flame 108 to prevent the burner 102 from being charged when a voltage, charge, and/or electric field is applied to the flame 108. According to an embodiment, a non-conductive gasket 120 can be employed as electrical insulator between the burner 102 and the flame 108. Suitable materials for the non-conductive gasket 120 can include neoprene, polyether ether ketone (PEEK), Viton fluoroelastomer, polytetrafluoroethylene (PTFE), polyethylene, fiberglass, and/or fiberglass-reinforced plastic, among others.
Moreover, to prevent contact between the interior walls of the combustion chamber 110 and the flame 108, the combustion chamber 110 can be coated with an electrically insulating refractory material 122. Suitable refractory materials 122 can include aluminum oxides, silicon oxides and/or magnesium oxides.
In applications where refractory materials 122 cannot be used, different configurations of electrodes can be employed to prevent the flame 108 from contacting the internal walls of the combustion chamber 110. For example, one or more electrodes can be properly attached to an interior wall of the combustion chamber 110 so that if the flame 108 is charged positively, then electrodes can also be charged positively to repel the flame 108.
The insulating properties of the non-conductive transfer structure 304 can eliminate electrical path to ground in the second safety insulation sub-system 300, protecting ancillary equipment 112 from potential high voltage discharges from the charged flame. In an embodiment, the non-conductive transfer structure 304 can include one or more non-conductive shafts 310 along with corresponding non-conductive couplings 312. In other embodiments, the non-conductive transfer structure 304 can employ magnetic couplings.
The motor 302 can be replaced by a suitable mechanical power supply mechanism, including internal combustion engines such as a gasoline engine. For example, the motor 302 can be replaced by a steam turbine, a compressed air turbine and the like.
Referring to step 402, a voltage, charge, or electric field applied to the combustion reaction can include operating at least one high voltage source to apply 1000 volts or more to the combustion reaction. In another embodiment, applying a voltage, charge, or electric field to the combustion reaction can include operating at least one high voltage source to apply 10,000 volts or more to the combustion reaction, for example.
Additionally or alternatively, applying a voltage, charge, or electric field to the combustion reaction can include operating at least one high voltage source to apply 1000 volts or more to one or more electrodes proximate to the combustion reaction. In another embodiment, applying a voltage, charge, or electric field to the combustion reaction can include operating at least one high voltage source to apply 10,000 volts or more to one or more electrodes proximate to the combustion reaction, for example.
Step 402 can include operating at least one high voltage source to apply a positive voltage or charge to or proximate to the combustion reaction.
Additionally or alternatively, applying a voltage, charge, or electric field to the combustion reaction can include operating at least one high voltage source to apply a negative voltage or charge to or proximate to the combustion reaction. Step 402 can include operating at least one high voltage source to apply a substantially constant voltage, charge, or electric field to the combustion reaction.
Referring to step 404, operating the electrically-powered ancillary apparatus can include operating ancillary equipment, operating one or more fan motors, one or more pumps, a fuel valve actuator, a damper actuator, and/or a digital computer or controller
Proceeding to step 406, substantially preventing electrical discharge from the combustion reaction through the electrically-powered ancillary apparatus can include preventing an electrical arc from forming between the combustion reaction and the electrically-powered ancillary apparatus and can include preventing damage to the electrically-powered ancillary apparatus.
Substantially preventing electrical discharge from the combustion reaction through the electrically-powered ancillary apparatus can include allowing current to flow through the electrically-powered ancillary apparatus at a rate less than 10% of an intended current flow path. In another embodiment, step 406 can include allowing current to flow through the electrically-powered ancillary apparatus at a rate less than 1% of an intended current flow path.
Step 406 can include providing at least one of electrical isolation and/or insulation disposed between the electrically-powered ancillary apparatus and one or more electrical discharge paths from the combustion reaction to the electrically-powered ancillary apparatus.
Step 406 can include providing a safety isolation system disposed between the electrically-powered ancillary apparatus and an electrical power source for the electrically-powered ancillary apparatus or between the electrically-powered ancillary apparatus and an electrical power source for the electrically-powered ancillary apparatus. Providing the safety isolation system can include providing at least a pair of insulated gate field effect transistors (IGFET) connected in a cascade across a DC power supply for the electrically-powered ancillary apparatus, a junction between the IGFETs forming an output terminal of a self-biasing amplifier for powering the electrically-powered ancillary apparatus. Providing a safety isolation system can include an inductive coupling to an output from the high voltage source and a step-down voltage transformer from the inductive coupling to power the electrically-powered ancillary equipment. Additionally or alternatively, step 406 can include providing an inductive coupling from the electrical power source for the electrically-powered ancillary apparatus.
In step 406, substantially preventing electrical discharge from the combustion reaction through the electrically-powered ancillary apparatus can further include providing an electrically insulated motor-generator pair, powering the motor from an external power source, providing rotational energy from the motor to the generator, and generating a voltage with the generator to run the electrically-powered ancillary apparatus.
Step 406 can include allowing a voltage to run the electrically-powered ancillary apparatus to electrically float on a voltage operatively coupled to the combustion reaction. Step 406 can further include operating a high voltage source to generate the voltage, charge, or electric field.
The method 400 can include providing a safety isolation system disposed between the electrically-powered ancillary apparatus and an electrical power source for the electrically-powered ancillary apparatus.
Substantially preventing electrical discharge from the combustion reaction through the electrically-powered ancillary apparatus can include providing electrical insulation, electrical isolation, or electrical insulation and electrical isolation disposed between the electrically-powered ancillary apparatus and an electrical power source for the electrically-powered ancillary apparatus.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments may be contemplated. The spirit and scope of the various embodiments disclosed herein may be applicable to any type of combustion system regardless of the type of fuel, application, among others. 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. 62/079,310, entitled “BURNER OR BOILER ELECTRICAL DISCHARGE CONTROL”, filed Nov. 13, 2014, co-pending at the time of filing, (docket number 2651-260-02); which, to the extent not inconsistent with the description herein, is incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62079310 | Nov 2014 | US |
