Combustion Stabilization Systems

Abstract

Systems for stabilizing combustion while minimizing NOx generation by using high-flame-speed additives to stabilize the flame front in combustors operating at relatively low temperatures and/or under oxygen constraints. The system is adapted for use in coal-fired boilers, oil-fired boilers, and gas turbine engines. The methods stabilize the flame front to permit stable combustion under an expanded range of part-load conditions. The system provides substantially complete combustion of coal in coal boilers resulting in ash saleable for use in concrete manufacturing.

1 . A combustion stabilization system, comprising the steps of:
 a) substantially optimizing combustion conditions for at least one first coal fuel mixture to substantially minimize NOx emissions;   b) burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions;   c) collecting at least one first coal-combustion byproduct generated by such NOx-minimizing burning;   d) selecting at least one high-flame-speed additive;   e) preheating such at least one high-flame-speed additive;   f) adding such at least one high-flame-speed additive to such at least one first coal-combustion byproduct to generate at least one higher-flame-speed fuel mixture;   g) substantially optimizing combustion conditions for such at least one higher-flame-speed fuel mixture to maximize combustion of such at least one higher-flame-speed fuel mixture;   h) injecting such at least one higher-flame-speed fuel mixture into at least one combustion chamber having at least one combustion initiator;   i) igniting such at least one higher-flame-speed fuel mixture with such at least one combustion initiator;   j) burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions; and   k) collecting at least one second coal-combustion byproduct generated by such combustion-maximizing burning.   
     
     
         2 . The combustion stabilization system, according to  claim 1 , wherein such step of injecting such at least one higher-flame-speed fuel mixture into at least one combustion chamber having at least one combustion initiator comprises the step of injecting at least one part-load of such at least one higher-flame-speed fuel mixture into at least one combustion chamber having at least one combustion initiator. 
     
     
         3 . The combustion stabilization system, according to  claim 1 , further comprising the step of selling such at least one second coal-combustion byproduct for use in cement manufacturing. 
     
     
         4 . The combustion stabilization system, according to  claim 1 , further comprising the step of adding urea to such at least one first coal-combustion byproduct prior to the step of collecting such at least one first coal-combustion byproduct generated by such NOx-minimizing burning. 
     
     
         5 . The combustion stabilization system, according to  claim 1 , further comprising the step of adding ammonia to such at least one first coal-combustion byproduct prior to the step of collecting such at least one first coal-combustion byproduct generated by such NOx-minimizing burning. 
     
     
         6 . The combustion stabilization system, according to  claim 1 , further comprising the step of adding calcium to such at least one first coal-combustion byproduct prior to the step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions. 
     
     
         7 . The combustion stabilization system, according to  claim 1 , further comprising the step of adding magnesium to such at least one first coal-combustion byproduct prior to the step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions. 
     
     
         8 . The combustion stabilization system, according to  claim 1 , further comprising the step of adding iron to such at least one first coal-combustion byproduct prior to the step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions. 
     
     
         9 . The combustion stabilization system, according to  claim 1 , wherein the step of selecting at least one high-flame-speed additive comprises the step of selecting at least one second coal fuel mixture. 
     
     
         10 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 1:10 ratio or less by mass. 
     
     
         11 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 1.5:10 ratio by mass. 
     
     
         12 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 2:10 ratio by mass. 
     
     
         13 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 2.5:10 ratio by mass. 
     
     
         14 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 3:10 ratio by mass. 
     
     
         15 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 3.5:10 ratio by mass. 
     
     
         16 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise about at least one 4:10 ratio by mass. 
     
     
         17 . The combustion stabilization system, according to  claim 9 , wherein such at least one first coal-combustion byproduct and such at least one high-flame-speed additive comprise at least one 4.5:10 ratio by mass. 
     
     
         18 . The combustion stabilization system, according to  claim 1 , wherein such step of burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions comprises the step of burning such at least one first coal fuel mixture in at least one atmosphere comprising about three percent oxygen at exit. 
     
     
         19 . The combustion stabilization system, according to  claim 1 , wherein such step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions comprises the step of burning such at least one higher-flame-speed fuel mixture in at least one atmosphere comprising about four percent oxygen at exit. 
     
     
         20 . The combustion stabilization system, according to  claim 1 , wherein such step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions comprises the step of burning such at least one higher-flame-speed fuel mixture in at least one atmosphere comprising about five percent oxygen at exit. 
     
     
         21 . The combustion stabilization system, according to  claim 1 , wherein such step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions comprises the step of burning such at least one higher-flame-speed fuel mixture in at least one atmosphere comprising about six percent oxygen at exit. 
     
     
         22 . The combustion stabilization system, according to  claim 1 , wherein such at least one second coal-combustion byproduct comprises less than about five percent carbon by mass. 
     
     
         23 . The combustion stabilization system, according to  claim 1 , wherein such at least one second coal-combustion byproduct comprises less than about four percent carbon by mass. 
     
     
         24 . The combustion stabilization system, according to  claim 1 , wherein such at least one second coal-combustion byproduct comprises less than about three percent carbon by mass. 
     
     
         25 . The combustion stabilization system, according to  claim 1 , wherein such at least one second coal-combustion byproduct comprises less than about two percent carbon by mass. 
     
     
         26 . The combustion stabilization system, according to  claim 1 , wherein such at least one second coal-combustion byproduct comprises less than about one percent carbon by mass. 
     
     
         27 . The combustion stabilization system, according to  claim 1 , wherein such step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber having such at least one combustion initiator comprises the step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber adjacent at least one highest-temperature region of such at least one combustion chamber. 
     
     
         28 . The combustion stabilization system, according to  claim 1 , wherein such step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber having such at least one combustion initiator comprises the step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber adjacent at least one highest-oxygen content region of such at least one combustion chamber. 
     
     
         29 . The combustion stabilization system, according to  claim 1 , wherein such step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber having such at least one combustion initiator comprises the step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber prior to such at least one first coal-combustion byproduct cooling to ambient temperature from such NOx-minimizing burning temperature. 
     
     
         30 . The combustion stabilization system, according to  claim 1 , wherein such at least one first coal-combustion byproduct comprises at least one fly ash and at least one bottom ash. 
     
     
         31 . The combustion stabilization system, according to  claim 1 , wherein such step of burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions and such step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions both occur in such at least one combustion chamber at different times. 
     
     
         32 . The combustion stabilization system, according to  claim 1 , further comprising the step of transferring at least one unused NOx emission credit. 
     
     
         33 . The combustion stabilization system, according to  claim 1 , further comprising the step of steam treating such at least one first coal-combustion byproduct. 
     
     
         34 . The combustion stabilization system, according to  claim 33 , wherein such step of adding such at least one high-flame-speed additive to such at least one first coal-combustion byproduct comprises the step of steam treating such at least one first coal-combustion byproduct. 
     
     
         35 . The combustion stabilization system, according to  claim 1 , wherein such step of selecting at least one high-flame-speed additive comprises the step of selecting at least one hydrocarbon. 
     
     
         36 . The combustion stabilization system, according to  claim 35 , wherein such step of selecting at least one hydrocarbon comprises the step of selecting at least one of the set comprising methane, ethane, propane, butanes, pentanes, hexanes, septanes, octanes, nonanes, decanes, toluene, benzene, acetone, mixtures of hydrocarbons where C<10, mixtures of hydrocarbons where C<20, diesel oil, no. 2 oil, heavy oil, jet fuel, acetylene, bio-derived oils, naphta, coal gasification products, and oil gasification products. 
     
     
         37 . The combustion stabilization system, according to  claim 35 , wherein such step of selecting at least one hydrocarbon comprises the step of selecting at least one of the set comprising at least one of alcohols, ethers, aldehydes, and ketones. 
     
     
         38 . The combustion stabilization system, according to  claim 1 , wherein such step of selecting at least one high-flame-speed additive comprises the step of selecting hydrogen. 
     
     
         39 . The combustion stabilization system, according to  claim 1 , further comprising the step of reducing milling of such at least one first coal fuel mixture prior to burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions in anticipation of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions 
     
     
         40 . The combustion stabilization system, according to  claim 1 , further comprising the step of reducing milling of at least one portion of such at least one higher-flame-speed fuel mixture prior to burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions. 
     
     
         41 . The combustion stabilization system, according to  claim 1 , further comprising the step of reducing milling of at least one portion of such at least one first coal-combustion byproduct prior to burning such at least one first coal-combustion byproduct under such substantially combustion maximizing conditions. 
     
     
         42 . The combustion stabilization system, according to  claim 1 , further comprising the steps of:
 a) reducing milling of such at least one first coal fuel mixture prior to burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions;   b) milling such at least one first coal-combustion byproduct; and   c) burning such at least one first coal-combustion byproduct under such substantially combustion maximizing conditions.   
     
     
         43 . The combustion stabilization system, according to  claim 42 , wherein mill electrical consumption is reduced by about twenty percent per ton of such at least one first coal fuel mixture. 
     
     
         44 . The combustion stabilization system, according to  claim 1 , wherein such step of injecting such at least one higher-flame-speed fuel mixture into such at least one combustion chamber having such at least one combustion initiator comprises the step of adding such at least one high-flame-speed additive to such at least one first coal-combustion byproduct to generate at least one higher-flame-speed fuel mixture. 
     
     
         45 . The combustion stabilization system, according to  claim 1 , wherein such at least one first coal-combustion byproduct comprises at least about five percent carbon by mass. 
     
     
         46 . The combustion stabilization system, according to  claim 1 , wherein such at least one first coal-combustion byproduct comprises at least about ten percent carbon by mass. 
     
     
         47 . The combustion stabilization system, according to  claim 1 , wherein such at least one first coal-combustion byproduct comprises at least about fifteen percent carbon by mass. 
     
     
         48 . The combustion stabilization system, according to  claim 1 , wherein such at least one first coal-combustion byproduct comprises at least about twenty percent carbon by mass. 
     
     
         49 . The combustion stabilization system, according to  claim 1 , wherein the step of burning such at least one first coal fuel mixture under such substantially NOx minimizing conditions occurs during substantially high-load (between about 70% and about 100% of maximum load) operations of such at least one at least one combustion chamber and such step of burning such at least one higher-flame-speed fuel mixture under such substantially combustion maximizing conditions occurs during part-load (below about 70% of maximum load) conditions of such at least one combustion chamber. 
     
     
         50 . The combustion stabilization system, according to  claim 49 , wherein such at least one combustion chamber comprises at least one coal-fired boiler.