Gradual oxidation with heat exchange media
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.
1. A system for oxidizing fuel, comprising:
an oxidizer having a reaction chamber with an inlet and an outlet, the reaction chamber configured (a) to receive a gas comprising an oxidizable fuel through the inlet, and (b) to maintain an oxidation process of the gas; and
heat exchange media disposed within the reaction chamber, the media being hotter than an auto-ignition temperature of the fuel;
a circulation path configured to circulate the media outside the reaction chamber;
a controller, comprising:
a detection module that detects (i) when an internal temperature of the reaction chamber is above a flameout temperature of the fuel and (ii) when a reaction chamber inlet temperature of the fuel is lower than the autoignition temperature of the fuel; and
a correction module that outputs instructions, based on the internal temperature and/or the inlet temperature detected by the detection module, to control a speed at which the media circulates through the circulation path such that an adiabatic temperature within the reaction chamber is below the flameout temperature of the mixture.
2. The system of claim 1 , wherein circulation of the media is configured to heat gas at the inlet and to maintain the inlet temperature of the fuel above the autoignition temperature.
3. The system of claim 1 , wherein circulation of the media is configured to draw heat from the gas within the reaction chamber to maintain the internal temperature of the gas beneath a flameout temperature of the gas.
4. The system of claim 1 , wherein the media comprises a plurality of steel structures that is circulated through the reaction chamber.
5. The system of claim 1 , wherein the media comprises a fluid that is circulated through the reaction chamber.
6. The system of claim 1 , wherein a speed that the media circulates is based on at least one of the internal temperature and the inlet temperature.
7. The system of claim 1 , wherein heat is drawn from the media when the media circulates outside the reaction chamber.
8. A system for oxidizing fuel, comprising:
an oxidizer having a reaction chamber with an inlet and an outlet, the reaction chamber configured to receive a gas mixture comprising an oxidizable fuel through the inlet, the oxidizer configured to maintain an oxidation process of the gas mixture within the reaction chamber; and
a recirculation pathway that directs at least a portion of product gas, after oxidation within the reaction chamber, toward the inlet of the reaction chamber and introduces the product gas into the reaction chamber at the inlet, the product gas being hotter than an auto-ignition temperature of the gas mixture;
wherein introduction of the product gas increases an inlet temperature of the gas mixture to be above the autoignition temperature of the gas mixture;
a controller, comprising:
a detection module that detects (i) when an internal temperature of the reaction chamber is above a flameout temperature of the fuel and (ii) when a reaction chamber inlet temperature of the fuel is lower than the autoignition temperature of the fuel; and
a correction module that outputs instructions, based on the internal temperature and/or the inlet temperature detected by the detection module, to control a speed at which the product gas circulates through the recirculation path such that the reaction chamber inlet temperature of the fuel is higher than the autoignition temperature of the fuel.
9. The system of claim 8 , wherein recirculation of the product gas decreases an oxygen content level within the reaction chamber.
10. The system of claim 8 , wherein an amount of product gas that is recirculated is based on the inlet temperature.
11. The system of claim 8 , wherein an amount of product gas that is recirculated is based on an internal temperature of the reaction chamber.
12. A system for oxidizing fuel, comprising:
an oxidizer having a reaction chamber with an inlet and an outlet, the reaction chamber configured to receive a gas comprising an oxidizable fuel through the inlet, the oxidizer configured to maintain an oxidation process of the gas within the reaction chamber; and
heat exchange media disposed within the reaction chamber, the media being hotter than an auto-ignition temperature of the fuel;
a circulation path configured to circulate the media outside the reaction chamber;
a controller, comprising:
a detection module that detects (i) when an internal temperature of the reaction chamber is above a flameout temperature and (ii) when a reaction chamber inlet temperature of the fuel is lower than the autoignition temperature of the fuel; and
a correction module that outputs instructions to control a speed at which the media circulates through the circulation path (i) to maintain an adiabatic temperature within the reaction chamber below the flameout temperature of the fuel and (ii) to maintain the reaction chamber inlet temperature of the fuel to be greater than the autoignition temperature of the fuel.
13. The system of claim 12 , wherein the heat exchange media comprises a fluid.
14. The system of claim 13 , wherein the fluid is circulated, and circulation of the media is configured to heat gas at the inlet and to maintain the inlet temperature of the gas above the autoignition temperature of the gas.
15. The system of claim 12 , wherein the heat exchange media comprises sand.
16. The system of claim 12 , wherein the heat exchange media comprises a plurality of uniformly stacked structures.
17. The system of claim 12 , wherein the heat exchange media comprises a plurality of stacked disk, each having a plurality of apertures through which the gas is permitted to flow.
18. The system of claim 12 , wherein heat exchange media is configured to conduct heat within the reaction chamber toward the inlet, whereby gas being received through the inlet is heated to above the autoignition temperature.
19. The system of claim 8 , further comprising a circulation path configured to circulate the product gas outside the reaction chamber and thereby draw heat from the reaction chamber to maintain the internal temperature below the flameout temperature.
20. The system of claim 12 , further comprising a circulation path configured to circulate the media outside the reaction chamber and thereby draw heat from the reaction chamber to maintain the internal temperature below the flameout temperature.