Method and apparatus for treating a combustion product stream

Abstract

An apparatus for treating a combustion product stream includes a burner assembly configured to support one or more flames, the burner assembly having at least a portion configured to be driven to or held at one or more first voltages. A collection surface is held at a voltage different than the one or more first voltages to attract particulates charged by the burner assembly.

1 . An apparatus for treating a combustion product stream, comprising:
 a burner assembly configured to support one or more flames, the burner assembly having at least a portion configured to be driven to or held at one or more first voltages;   a burner support configured to support the burner assembly in a combustion product stream received from a combustion volume at a first location;   a power supply operatively coupled to the portion of the burner assembly operable to be driven to or held at one or more first voltages, the power supply being configured to output the first voltage to the burner assembly; and   at least one collection surface in contact with the combustion product stream at a second location selected to cause the combustion product stream to flow past the first location before flowing past the second location, the collection surface being configured to be held at or driven to at least one second voltage or ground different than the at least one first voltage.   
     
     
         2 . The apparatus of  claim 1 , wherein the burner assembly includes a burner electrode configured to be driven to or held at the one or more first voltages. 
     
     
         3 . The apparatus of  claim 1 , wherein the burner assembly includes a burner nozzle; and
 wherein the portion of the burner assembly configured to be driven to or held at the one or more first voltages includes the burner nozzle.   
     
     
         4 . The apparatus of  claim 1 , wherein the burner support is configured to hold the burner assembly within a flue configured to receive the combustion product stream from the combustion volume. 
     
     
         5 . The apparatus of  claim 1 , wherein the burner support is configured to hold the burner assembly at a location in the combustion product stream where the combustion product stream is substantially non-ionized. 
     
     
         6 . The apparatus of  claim 5 , wherein the one or more flames supported by the burner assembly are configured to provide ionized species to the combustion product stream; and
 wherein the at least a portion of the burner assembly operable to be driven to or held at one or more first voltages is configured to at least intermittently withdraw a portion of the ionized species provided by the one or more flames to produce a charge imbalance in the combustion product stream.   
     
     
         7 . The apparatus of  claim 1 , wherein the burner assembly includes a ring-burner operable to support a plurality of flames. 
     
     
         8 . The apparatus of  claim 1 , wherein the power supply is configured to output a time-varying first voltage. 
     
     
         9 . The apparatus of  claim 1 , wherein the one or more first voltages include a positive voltage configured to withdraw electrons from the one or more flames supported by the burner assembly. 
     
     
         10 . The apparatus of  claim 1 , wherein the one or more first voltages comprise a substantially constant voltage. 
     
     
         11 . The apparatus of  claim 1 , wherein the power supply is configured to output a time-varying first voltage to the burner assembly; and
 wherein the power supply is configured to output a time-varying second voltage to the collection surface, the time-varying second voltage being opposite in electrical polarity from the time-varying first voltage during a majority of instants having finite duration.   
     
     
         12 . The apparatus of  claim 11 , wherein the combustion product stream includes particulates. 
     
     
         13 . The apparatus of  claim 11 , wherein the collection surface is configured to attract electrically charged species from the combustion product stream. 
     
     
         14 . The apparatus of  claim 11 , further comprising:
 a scraper operable to scrape the collection surface to remove collected particulates from the combustion gas stream.   
     
     
         15 . The apparatus of  claim 11 , further comprising a field-driving surface arranged in opposition to the collection surface and separated from the collection surface by at least a portion of the combustion product stream, the field-driving surface being configured to be driven or held to at least one third voltage selected to create an electrical voltage gradient across the at least a portion of the combustion product stream between the field-driving surface and the collection surface. 
     
     
         16 . The apparatus of  claim 15 , wherein the at least one third voltage corresponds to the at least one first voltage. 
     
     
         17 . The apparatus of  claim 15 , wherein the field-driving surface includes a rod supported along an axis of a flue through which the combustion product stream flows;
 wherein the collection surface includes a surface located concentric to the field driving surface; and   wherein the electrical voltage gradient is formed radially between the field-driving surface and the collection surface.   
     
     
         18 . The apparatus of  claim 11 , wherein the one or more first voltages are opposite in polarity to the one or more second voltages. 
     
     
         19 . A system comprising:
 a combustion apparatus operable to burn a first fuel and output a combustion product stream;   a flue, stack, or pipe configured to convey the combustion product stream from the combustion apparatus;   a burner assembly arranged at a first location in the flue, stack, or pipe, operable to burn a second fuel and support one or more flames;   an electrode assembly proximate the burner assembly, configured to be driven to or held at one or more first voltages; and   a collection surface arranged at a second location in the flue, stack, or pipe selected to receive the combustion product stream after the combustion product stream is conveyed past the first location and configured to be driven or held at one or more second voltages or ground different from the first voltage.   
     
     
         20 . The system of  claim 19 , wherein the combustion apparatus includes an internal combustion engine. 
     
     
         21 . The system of  claim 19 , wherein the combustion apparatus includes an external combustion power source. 
     
     
         22 . The system of  claim 19 , wherein the first fuel includes diesel, coal, or bunker fuel. 
     
     
         23 . The system of  claim 19 , wherein the second fuel includes natural gas, propane, or butane. 
     
     
         24 . The system of  claim 19 , wherein the first and second fuels are different fuels. 
     
     
         25 . The system of  claim 19 , wherein the first and second fuels are substantially the same fuel. 
     
     
         26 . The system of  claim 19 , wherein the burner assembly and the electrode assembly are substantially coextensive. 
     
     
         27 . The system of  claim 19 , wherein the combustion product stream includes unburned fuel, ash, or unburned fuel and ash;
 wherein the burner assembly is configured to provide ionized species to the combustion product stream;   wherein the electrode assembly is configured to cause a charge imbalance in the ionized species;   wherein the unburned fuel, ash, or unburned fuel and ash receive charge corresponding to the charge imbalance to produce charged unburned fuel, ash, or unburned fuel and ash; and   wherein the collection surface is configured to electrically attract the charged unburned fuel, ash, or unburned fuel and ash out of the combustion product stream.   
     
     
         28 . A method of treating a combustion product stream, comprising:
 maintaining a flame at a first location in a substantially non-ionized combustion product stream to produce electrically charged species;   applying at least one first electrical potential proximate to the flame to preferentially attract a portion of the electrically charged species and produce a charge imbalance in the combustion product stream;   providing a collection surface in or adjacent to the combustion product stream at a second location exposed to the charge imbalance; and   applying at least one second electrical potential at ground or opposite in polarity to the at least one first electrical potential to attract charged particles from the combustion product stream to the collection surface.   
     
     
         29 . The method of  claim 28 , further comprising:
 providing a field-driving electrode proximate to the second location and spaced away from the collection surface by at least a portion of the combustion product stream carrying the charge imbalance; and   applying at least one third electrical potential to the field-driving electrode to create a voltage difference between the field-driving electrode and the collection surface.   
     
     
         30 . The method of  claim 29 , wherein at least one first electrical potential and the at least one third electrical potential include electrical potentials at the same polarity. 
     
     
         31 . The method of  claim 30 , wherein the at least one first electrical potential and the at least one third electrical potential include positive electrical potentials. 
     
     
         32 . The method of  claim 28 , wherein the combustion product stream includes particulates; and further comprising:
 selecting first and second locations having a separation sufficient to allow the charge imbalance to associate with the particulates.   
     
     
         33 . The method of  claim 28 , further comprising:
 providing a burner apparatus to support the flame; and   providing fuel to the burner apparatus to maintain the flame.   
     
     
         34 . The method of  claim 33 , wherein the fuel is different than a second fuel that produced the combustion product stream. 
     
     
         35 . The method of  claim 33 , wherein applying at least one first electrical potential proximate to the flame includes applying a voltage to at least a portion of the burner apparatus. 
     
     
         36 . The method of  claim 28 , wherein applying the at least one first electrical potential includes modulating an electrical potential including one or more positive voltages. 
     
     
         37 . The method of  claim 28 , wherein the collection surface includes a cylindrical surface substantially coincident with a flue, pipe, or stack through which the combustion product stream flows. 
     
     
         38 . The method of  claim 28 , further comprising:
 at least intermittently removing adhered particulates from the collection surface.   
     
     
         39 . The method of  claim 38 , wherein at least intermittently removing the adhered particulates from the collection surface includes one or more of driving a scraper, driving a shaker, applying compressed gas, or applying a vacuum to the collection surface. 
     
     
         40 . The method of  claim 28 , wherein applying the at least one second potential or ground to the collection surface substantially removes particulates from the combustion product stream.