Gradual oxidation and multiple flow paths

Abstract

Described herein are embodiments of systems and methods for oxidizing gases. In some embodiments, a reaction chamber is configured to receive a fuel gas and maintain the gas at a temperature within the reaction chamber that is above an autoignition temperature of the gas. The reaction chamber may also be configured to maintain a reaction temperature within the reaction chamber below a flameout temperature. In some embodiments, heat and product gases from the oxidation process can be used, for example, to drive a turbine, reciprocating engine, and injected back into the reaction chamber.

What is claimed is: 
     
         1 . A method of oxidizing a fuel, comprising:
 mixing a gas having a low-energy-content (LEC) fuel to form a gas mixture with at least one of a gas comprising a high-energy-content (HEC) fuel, a gas comprising an oxidant, and a gas comprising a diluent while each gas of the gas mixture is at a temperature below an autoignition temperature of every gas of the gas mixture;   increasing a temperature of the gas mixture to at least an autoignition temperature of the gas mixture and allowing the gas mixture to autoignite; and   maintaining the temperature of the gas mixture below a flameout temperature while the gas mixture oxidizes.   
     
     
         2 . The method of  claim 1 , wherein the gas mixture is raised to at least the autoignition temperature of the gas mixture by a heat exchanger. 
     
     
         3 . The method of  claim 2 , wherein the heat exchanger is positioned within a reaction chamber that maintains oxidation of the gas mixture without a catalyst. 
     
     
         4 . The method of  claim 1 , wherein the gas mixture is raised to at least the autoignition temperature of the gas mixture within a reaction chamber that maintains oxidation of the gas mixture without a catalyst. 
     
     
         5 . The method of  claim 4 , wherein the reaction chamber maintains oxidation of the gas mixture beneath the flameout temperature of the gas mixture. 
     
     
         6 . The method of  claim 4 , further comprising expanding the gas mixture with a turbine or a piston engine that receives the gas mixture from the reaction chamber. 
     
     
         7 . The method of  claim 4 , wherein the gas mixture comprises at least one of hydrogen, methane, ethane, ethylene, natural gas, propane, propylene, propadiene, n-butane, iso-butane, butylene-1, butadiene, iso-pentane, n-pentane, acetylene, hexane, and carbon monoxide. 
     
     
         8 . The method of  claim 1 , wherein the gas mixture oxidizes within a reaction chamber having an inlet. 
     
     
         9 . The method of  claim 8 , wherein the temperature of the gas mixture is maintained below the flameout temperature by a heat exchange media disposed within the reaction chamber. 
     
     
         10 . The method of  claim 9 , further comprising maintaining a reaction chamber inlet temperature of the reaction chamber to be greater than the autoignition temperature of the gas mixture by transferring heat through the heat exchange media. 
     
     
         11 . The method of  claim 10 , further comprising directing the gas mixture through a first path having a portion of the heat exchange media that is hotter than the autoignition temperature of the gas mixture until the gas mixture reaches a temperature above the autoignition temperature of the gas mixture. 
     
     
         12 . The method of  claim 11 , further comprising directing the gas mixture through a second path to an outlet of the reaction chamber, the second path being generally opposite to the first path. 
     
     
         13 . The method of  claim 12 , wherein the reaction chamber maintains oxidation of the gas mixture beneath a flameout temperature of the gas mixture by circulating the heat exchange media outside the reaction chamber. 
     
     
         14 . The method of  claim 12 , further comprising expanding gas with a turbine or a piston engine that receives the gas mixture from the outlet of the reaction chamber. 
     
     
         15 . The method of  claim 1 , further comprising, after the increasing the temperature of the gas mixture, injecting into an additional mixture the low-energy-content (LEC) fuel and the high-energy-content (HEC) fuel, wherein a rate of the injecting is selected to produce substantially a same ratio as a ratio of the low-energy-content (LEC) and the high-energy-content (HEC) fuel to the gas mixture. 
     
     
         16 . The method of  claim 15 , further comprising mixing the additional mixture with the gas mixture at a rate to produce a substantially homogeneous mixture in a time less than an ignition delay time for the additional mixture while allowing the substantially homogeneous mixture to auto-ignite. 
     
     
         17 . The method of  claim 16 , further comprising maintaining a temperature of the substantially homogeneous mixture below a flameout temperature of the substantially homogeneous mixture while the substantially homogeneous mixture oxidizes. 
     
     
         18 . The method of  claim 17 , wherein the substantially homogeneous mixture is raised to at least the autoignition temperature within a reaction chamber that maintains oxidation of the substantially homogeneous mixture without a catalyst. 
     
     
         19 . The method of  claim 18 , wherein the reaction chamber maintains oxidation of the substantially homogeneous mixture beneath a flameout temperature of the substantially homogeneous mixture.