Systems, apparatus and method for flameless combustion absent catalyst or high temperature oxidants

Abstract

A system, apparatus and method whereby flameless combustion is precipitated and maintained in a combustion chamber having a surface that is either convex concave, straight or any combination thereof without the need for catalysts or high temperature oxidants. The apparatus allows the combustion chamber to operate in a conventional combustion mode and a flameless combustion mode. The method provides for hot air and fuel gas to both be inerted prior to their mixing so long as their blend temperatures are within the 1000° F. to the 1400° F. range. The inert hot air and the inert fuel gas flow side by side along the chamber's internal surface so that the two gases mix more uniformly, thereby allowing flameless combustion at lower temperatures resulting in low NO x emissions.

1 . A method to precipitate and sustain flameless combustion within a combustion chamber defined by an internal surface, the method comprising the steps of: 
 introducing air into the combustion chamber via a first air injection nozzle in a generally conical dispersion pattern about a first air path that is generally parallel to the internal surface of the combustion chamber;    providing flue gas within the combustion chamber;    introducing fuel gas into the combustion chamber via a first fuel gas tip in a generally conical dispersion pattern about a first fuel gas path that is generally parallel to the internal surface of the combustion chamber;    inerting the fuel gas with the flue gas;    inerting the air with the flue gas; and    continuing to separately introduce the air and the fuel gas such that the generally conical dispersions of inerted air and inerted fuel gas diffuse into a molecular composite within a flameless combustion boundary area and reach or exceed the auto ignition temperature of the molecular composite.    
   
   
       2 . The method of  claim 1  wherein the molecular composite has a blend temperature, wherein the blend temperature is in a range from 1100° F. to 1400° F.  
   
   
       3 . The method of  claim 2  further comprising the step of maintaining a blend temperature of the molecular composite of generally between 1000° F. to 1400° F. while simultaneously providing an exiting means by which internal pressure of the combustion chamber may be equalized in consideration of the introduction of the fuel gas and the air into the combustion chamber.  
   
   
       4 . The method of  claim 3  wherein the exiting means is an exhaust duct.  
   
   
       5 . The method of  claim 1  wherein the internal surface is convex, concave, straight, or a combination thereof.  
   
   
       6 . The method of  claim 1 , wherein the air is preheated to a temperature generally ranging from 850° F. and higher.  
   
   
       7 . The method of  claim 1  wherein the fuel gas is selected from the fuel gases H 2 , CO, CH 4 , C 2 H 6 , C 2 H 4 , C 3 H 8 , C 3 H 6 , C 4 H 10 , C 4 H 8 , C 5 H 12 , and C 6 H 14 .  
   
   
       8 . The method of  claim 3  wherein the step of sustaining flameless combustion by maintaining the blend temperature between 1000° F. to 1400° F. further comprises controlling introduction of fuel gas according to software-controlled temperature sensing means.  
   
   
       9 . The method of  claim 3  wherein the step of sustaining flameless combustion by maintaining the blend temperature between 1000° F. to 1400° F. further comprises controlling introduction of air according to software-controlled temperature sensing means.  
   
   
       10 . The method of  claim 3  wherein the step of sustaining flameless combustion by maintaining the blend temperature between 1000° F. to 1400° F. produces a quantity of NO x  emissions in the range between 5 to 8 ppm.  
   
   
       11 . The method of  claim 10  further comprising the step of providing a noble metal screen downstream of the exiting means for further reducing the quantity of NO x  emissions to about 3 ppm.  
   
   
       12 . The method of  claim 11  wherein the noble metal screen is made of a noble metal selected from the group consisting of gold, silver, platinum, palladium, tantalum, rhodium, ruthenium, rhenium, osmium, and iridium.  
   
   
       13 . The method of  claim 11  wherein the noble metal screen is made of a noble metal alloy.  
   
   
       14 . The method of  claim 1  wherein the generally conical dispersions of inert air and inert fuel gas diffuse into each other between the generally parallel first air path and first fuel gas path.  
   
   
       15 . The method of  claim 1  wherein inerting the air with the flue gas is facilitated by installing mixer blades on the first air injection nozzle.  
   
   
       16 . The method of  claim 1  wherein the step of providing flue gas within the combustion chamber is performed by introducing externally-generated flue gas into the combustion chamber.  
   
   
       17 . The method of  claim 1  wherein the step of providing flue gas within the combustion chamber is performed by creating flue gas inside the combustion chamber.  
   
   
       18 . The method of  claim 1  further comprising providing a second air injection nozzle disposed to introduce air in a generally conical dispersion pattern about a second air path that is generally parallel to the internal surface of the combustion chamber.  
   
   
       19 . The method of  claim 1  further comprising providing a second air injection nozzle downstream from the first air injection nozzle and disposed to introduce air in a generally conical dispersion pattern about a second air path that is generally parallel to the internal surface of the combustion chamber.  
   
   
       20 . The method of  claim 1  further comprising providing a second fuel gas tip disposed to introduce fuel gas in a generally conical dispersion pattern about a second fuel gas path that is generally parallel to the internal surface of the combustion chamber.  
   
   
       21 . The method of  claim 1  further comprising providing a second fuel gas tip downstream from the first fuel gas tip and disposed to introduce fuel gas in a generally conical dispersion pattern about a second fuel gas path that is generally parallel to the internal surface of the combustion chamber.  
   
   
       22 . The method of  claim 1  further comprising spacing the first air injection nozzle downstream from the first fuel gas tip.  
   
   
       23 . A method to convert from conventional combustion to flameless combustion within a combustion chamber comprising the steps of: 
 providing a combustion chamber having an internal surface and a hot air injection nozzle disposed on the internal surface to inject hot air into the combustion chamber;    providing a burner disposed on the internal surface of the combustion chamber, comprising: 
 a fuel gas tip within an exhaust duct, which is disposed on the internal surface of the combustion chamber;  
 an ambient air injection nozzle disposed on the internal surface to inject ambient air into the combustion chamber  
 a venturi disposed to receive flue gas from an exhaust duct and fuel gas from the fuel gas tip, the venturi providing the flue gas and the fuel gas through the ambient air injection nozzle and into the combustion chamber; and  
 a pilot gas tip disposed on the internal surface downstream of the venturi;  
 introducing ambient air to the combustion chamber via the ambient air injection nozzle;  
   providing flue gas within the combustion chamber;    introducing fuel gas via the fuel gas tip;    inerting the fuel gas with the flue gas;    lighting the pilot gas tip to initiate conventional combustion;    reducing the ambient air flow through the ambient air injection nozzle while simultaneously introducing hot air into the combustion chamber via the hot air injection nozzle, wherein the reduction of ambient air flow is substantially equal to the increase in hot air flow;    inerting the hot air with the flue gas;    eliminating the ambient air flow; and    continuing to introduce fuel gas and hot air so that the inerted hot air and the inerted fuel gas diffuse into a molecular composite and reach or exceed the auto ignition temperature of the molecular composite to precipitate flameless combustion.    
   
   
       24 . The method of  claim 23  wherein the molecular composite has a blend temperature in a range from 1000° F. to 1400° F.  
   
   
       25 . An apparatus for precipitating and maintaining flameless combustion comprising; 
 a combustion chamber having an internal surface;    a first exhaust duct in the internal surface;    a first burner disposed on the internal surface of the combustion chamber comprising: 
 a first ambient air injection nozzle disposed to inject ambient air into the combustion chamber;  
 a venturi disposed to receive fuel gas from a fuel gas tip;  
 a first pilot gas tip disposed downstream of the venturi to selectively ignite an ambient air and fuel gas mixture downstream of the venturi; and  
   a first hot air injection nozzle disposed on the internal surface.    
   
   
       26 . The apparatus of  claim 25  wherein the first hot air injection nozzle is downstream of the first fuel gas tip.  
   
   
       27 . The apparatus of  claim 25  further comprising a second exhaust duct disposed on the internal surface.  
   
   
       28 . The apparatus of  claim 25  wherein the first venturi is disposed within the first exhaust duct and is in communication with the first ambient air nozzle.  
   
   
       29 . The apparatus of  claim 25  wherein the first pilot gas tip is downstream of the first ambient air injection nozzle.  
   
   
       30 . The apparatus of  claim 25  further comprising a second burner disposed on the internal surface.  
   
   
       31 . The apparatus of  claim 25  further comprising a second hot air injection nozzle disposed on the internal surface.  
   
   
       32 . The apparatus of  claim 31  wherein the first hot air injection nozzle and the second hot air injection nozzle are located downstream of the first fuel gas tip.  
   
   
       33 . The apparatus of  claim 25  wherein the internal surface is convex, concave, straight, or a combination thereof.  
   
   
       34 . The apparatus of  claim 25  further comprising a mixer blade on the first air injection nozzle.  
   
   
       35 . The apparatus of  claim 25  further comprising a noble metal screen located downstream of the first exhaust duct.  
   
   
       36 . The apparatus of  claim 35  wherein the noble metal screen is made of a noble metal selected from the group consisting of gold, silver, platinum, palladium, tantalum, rhodium, ruthenium, rhenium, osmium and iridium.  
   
   
       37 . The apparatus of  claim 35  wherein the noble metal screen is made of a noble metal alloy.  
   
   
       38 . The apparatus of  claim 25  wherein the combustion chamber further comprises a first heat transfer cooling coil.  
   
   
       39 . The apparatus of  claim 25  wherein the internal surface of the combustion chamber is separated into a first layer and a second layer by a corbel.  
   
   
       40 . The apparatus of  claim 39  wherein the first layer comprises the first burner and first hot air injection nozzle and the second layer comprises a first burner and a first hot air injection nozzle.  
   
   
       41 . The apparatus of  claim 39  wherein air, fuel gas, and flue gas in the first layer travel in a first direction, and air, fuel gas, and flue gas travel in an opposite second direction in the second layer.  
   
   
       42 . A system to precipitate and maintain flameless combustion within a combustion chamber of an integrated heater/burner apparatus comprising: 
 a combustion chamber, wherein ambient air, hot air and fuel gas enter the combustion chamber, and flue gas exits the combustion chamber;    a convection section, located downstream of the combustion chamber, for heating a heat transfer cooling coil using the flue gas from the exit of the combustion chamber;    a stack having a stack damper, located downstream of the convection section, capable of natural draft operation when the stack damper is open and air preheat operation when the stack damper is closed;    an air preheater, located upstream of the combustion chamber, for converting ambient air to hot air;    a forced draft fan having a forced draft fan damper, located upstream of the air preheater, for supplying hot air to the combustion chamber via the air preheater; and    an induced draft fan having an induced draft fan damper, located downstream of the air preheater and upstream of the stack on the flue gas side, for inducing the flue gas through the air preheater and delivering the flue gas to the stack.    
   
   
       43 . The system of  claim 42  wherein the flue gas exiting the combustion chamber has a quantity of NO x  emissions in the range of 5-8 ppm.  
   
   
       44 . The system of  claim 42  further comprising a noble metal screen, located downstream of the combustion chamber and upstream of the convection section, for further reducing the quantity of NO x  emissions to about 3 ppm.  
   
   
       45 . The system of  claim 44  wherein the noble metal screen is made of a noble metal selected from the group consisting of gold, silver, platinum, palladium, tantalum, rhodium, ruthenium, rhenium, osmium, and iridium.  
   
   
       46 . The system of  claim 44  wherein the noble metal screen is made of a noble metal alloy.  
   
   
       47 . The system of  claim 44  wherein the ambient air supply, the stack damper, the forced draft fan damper and the induced fan draft damper are controlled automatically via a computer program.  
   
   
       48 . The system of  claim 44  wherein the ambient air supply, the stack damper, the forced draft fan damper and the induced fan draft fan damper are controlled manually.