Catalytic combustor and method for substantially eliminating nitrous oxide emissions

#The present invention relates generally to gas powered turbines for generating power, and more particularly to a low nitrous oxide emission combustion system for gas powered turbine systems.

#It is generally known in the art to power turbines with gases being expelled from combustion chambers. These gas powered turbines can produce power for many applications such as terrestrial power plants. In the gas powered turbine a fuel, such as a hydrocarbon (for example methane or kerosene) or hydrogen, is combusted in an oxygen rich environment. Generally, these combustion systems have high emissions of undesirable compounds such as nitrous oxide compounds (NOX) and carbon containing compounds. It is generally desirable to decrease these emissions as much as possible so that undesirable compounds do not enter the atmosphere. In particular, it has become desirable to reduce NOX emissions to a substantially low amount. Emissions of NOX are generally desired to be non-existent, and are accepted to be non-existent, if they are equal to or less than about one part per million volume of dry weight emissions.

#In a combustion chamber fuel, such as methane, is combusted in atmospheric air where temperatures generally exceed about 1427° C. (about 2600° F.). When temperatures are above 1427° C., the nitrogen and oxygen compounds, both present in atmospheric air, undergo chemical reactions which produce nitrous oxide compounds. The energy provided by the high temperatures allows the breakdown of dinitrogen and dioxygen, especially in the presence of other materials such as metals, to produce NOX compounds such as NO2 and NO.

#The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

#FIG. 1 is a perspective view of a gas powered turbine including a combustor in accordance with the present invention;

#FIG. 2 is a partial cross-sectional perspective view of a single combustor;

#The following description of the various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Specifically, although the following combustor is described in conjunction with a terrestrial gas turbine, it may be used in other systems. Furthermore, the mixer and heat exchanger may be used in systems other than turbine systems.

#Referring to FIG. 1, a gas powered turbine in accordance with a preferred embodiment of the present invention is shown. The gas powered combustion turbine 10 may use several different gaseous fuels, such as hydrocarbons (including methane and propane) and hydrogen, that are combusted and that expand to move portions of the gas powered turbine 10 to produce power. An important component of the gas powered turbine 10 is a compressor 12 which forces atmospheric air into the gas powered turbine 10. Also, the gas powered turbine 10 includes several combustion chambers 14 for combusting fuel. The combusted fuel is used to drive a turbine 15 including turbine blades or fans 16 which are axially displaced in the turbine 15. There are generally a plurality of turbine fans 16, however, the actual number depends upon the power the gas powered turbine 10 is to produce. Only a single turbine fan is illustrated for clarity.

#In general, the gas powered turbine 10 ingests atmospheric air, combusts a fuel in it, which powers the turbine fans 16. Essentially, air is pulled in and compressed with the compressor 12, which generally includes a plurality of concentric fans which grow progressively smaller along the axial length of the compressor 12. The fans in the compressor 12 are all powered by a single axle. The high pressure air then enters the combustion chambers 14 where fuel is added and combusted. Once the fuel is combusted, it expands out of the combustion chamber 14 and engages the turbine fans 16 which, due to aerodynamic and hydrodynamic forces, spins the turbine fans 16. The gases form an annulus that spin the turbine fans 16, which are affixed to a shaft (not shown). Generally, there are at least two turbine fans 16. One or more of the turbine fans 16 engage the same shaft that the compressor 12 engages.