Electrodynamic combustion control (ecc) technology for biomass and coal systems

Abstract

A solid fuel combustion system includes a solid fuel support configured to hold a solid fuel for a combustion reaction. A field electrode is positioned above the solid fuel support. A voltage source supplies a first voltage the solid fuel support and a second voltage to the field electrode.

What is claimed is: 
     
         1 . A solid fuel combustion system, comprising:
 a solid fuel support configured to hold a solid fuel for a combustion reaction;   a voltage source coupled to the solid fuel support and configured to output a first voltage signal to the solid fuel support; and   a first field electrode coupled to the voltage source and disposed in or adjacent to a combustion reaction region above the solid fuel support, the voltage source configured to output a second voltage signal to the first field electrode while the first voltage signal is applied to the solid fuel support, the second voltage signal being different than the first voltage signal.   
     
     
         2 . The solid fuel combustion system of  claim 1 , wherein the first field electrode is configured to apply an electric field to the combustion region above the solid fuel support when receiving the second voltage signal. 
     
     
         3 . The solid fuel combustion system of  claim 2 , wherein the electric field is selected to cause the combustion reaction to burn more vigorously than in an absence of the electric field. 
     
     
         4 . The solid fuel combustion system of  claim 2 , wherein the electric field is selected to cause the combustion reaction supported by the solid fuel to output reduced oxides of nitrogen (NOx) than in an absence of the electric field. 
     
     
         5 . The solid fuel combustion system of  claim 2 , wherein the electric field is selected to cause the combustion reaction to evolve reduced carbon monoxide (CO) than in an absence of the electric field. 
     
     
         6 . The solid fuel combustion system of  claim 1 , wherein the second voltage signal is ground. 
     
     
         7 . The solid fuel combustion system of  claim 1 , wherein the second voltage signal has an opposite polarity from the first voltage signal. 
     
     
         8 . The solid fuel combustion system of  claim 7 , wherein the second voltage signal comprises a high voltage opposite in polarity from the first voltage signal. 
     
     
         9 . The solid fuel combustion system of  claim 1 , wherein the voltage signal is a first time-varying voltage signal and the second voltage signal is opposite in polarity from the first time-varying voltage signal. 
     
     
         10 . The solid fuel combustion system of  claim 9 , wherein the first time-varying voltage signal comprises a chopped DC waveform. 
     
     
         11 . The solid fuel combustion system of  claim 9 , wherein the first time-varying voltage signal comprises a DC offset AC waveform. 
     
     
         12 . The solid fuel combustion system of  claim 9 , wherein the first time-varying voltage signal comprises an AC waveform. 
     
     
         13 . The solid fuel combustion system of  claim 1 , wherein the first field electrode includes a metal. 
     
     
         14 . The solid fuel combustion system of  claim 1 , wherein the first field electrode includes porcelain coated metal. 
     
     
         15 . The solid fuel combustion system of  claim 1 , wherein the first field electrode includes silicon carbide (SiC). 
     
     
         16 . The solid fuel combustion system of  claim 1 , comprising a second field electrode coupled to the voltage source, the first and second field electrodes being disposed in or adjacent to walls of a furnace defining the combustion region above the solid fuel support. 
     
     
         17 . The solid fuel combustion system of  claim 1 , wherein the voltage source is configured output the second voltage signal to the second field electrode. 
     
     
         18 . The solid fuel combustion system of  claim 1 , wherein the solid fuel support is a conductive grate. 
     
     
         19 . The solid fuel combustion system of  claim 1 , wherein the first field electrode is a toroidal field electrode positioned above the solid fuel support. 
     
     
         20 . A method comprising:
 initiating a combustion reaction of a solid fuel positioned on a solid fuel support;   applying a first voltage signal to the solid fuel support; and   applying a second voltage signal to a first field electrode disposed in or adjacent to the combustion reaction above the solid fuel support.   
     
     
         21 . The method of  claim 20 , wherein the first field electrode has a toroid shape and is positioned above the combustion reaction. 
     
     
         22 . The method of  claim 21 , comprising contracting or extending a length of the combustion reaction by applying the second voltage to the first field electrode. 
     
     
         23 . The method of  claim 20 , comprising expanding or contracting a width of the combustion reaction by applying the second voltage signal to a second field electrode positioned adjacent to the combustion reaction. 
     
     
         24 . The method of  claim 20 , comprising generating an electric field in or near the combustion reaction by applying the first and second voltages to the solid fuel support and the first field electrode, respectively. 
     
     
         25 . The method of  claim 24 , wherein generating the electric field causes the combustion reaction to burn more vigorously than in an absence of the electric field. 
     
     
         26 . The method of  claim 25 , comprising reducing oxides of nitrogen (NOx) produced by the combustion reaction by generating the electric field. 
     
     
         27 . The method of  claim 24 , comprising reducing carbon monoxide (CO) produced by the combustion reaction by generating the electric field. 
     
     
         28 . The method of  claim 20 , wherein either the first or the second voltage signal is ground. 
     
     
         29 . The method of  claim 20 , wherein the second voltage signal is a high voltage opposite in polarity from the first voltage. 
     
     
         30 . The method of  claim 20 , wherein the first voltage signal is a time-varying voltage signal. 
     
     
         31 . The method of  claim 20 , wherein the second voltage signal is a time-varying voltage signal. 
     
     
         32 . The method of  claim 20 , wherein one or both of the first and second voltage signals is a chopped DC waveform. 
     
     
         33 . The method of  claim 20 , wherein one or both of the first and second voltage signals is a DC offset AC waveform. 
     
     
         34 . The method of  claim 20 , wherein the solid fuel is a biomass. 
     
     
         35 . The method of  claim 20 , wherein the solid fuel is coal.