Staged gradual oxidation
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:
a first reaction chamber with a first inlet and a first outlet, the first reaction chamber configured to receive a first gas comprising a first oxidizable fuel and air, the first reaction chamber configured to maintain a gradual oxidation process of the first fuel; and
a second reaction chamber with a second inlet and a second outlet, the second reaction chamber configured to receive through the second inlet (i) flue gas from the first outlet, the flue gas comprising heated product gas from oxidation of the first gas in the first reaction chamber and (ii) a second gas comprising a second oxidizable fuel, the second reaction chamber configured to maintain a gradual oxidation process of the second fuel;
wherein no source of air apart from the product gas is connected to a pathway between the first outlet and the second inlet;
wherein the first and second reaction chambers are configured to maintain an internal temperature in the respective reaction chambers below a flameout temperature of the respective fuel.
2. The system of claim 1 , further comprising heat exchange media disposed within at least one of the first and second reaction chambers, the heat exchange media configured to maintain an internal temperature of at least one of the first and second reaction chambers below an adiabatic flameout temperature.
3. The system of claim 1 , wherein at least one of the first and second reaction chambers is configured to reduce a respective internal temperature when an adiabatic temperature within the respective reaction chamber approaches or exceeds the flameout temperature of the respective fuel.
4. The system of claim 3 , wherein at least one of first and second reaction chambers is configured to reduce the respective internal temperature by removing heat from the respective reaction chamber by a heat exchanger.
5. The system of claim 4 , wherein the heat exchanger comprises a fluid introduced into the respective reaction chamber.
6. The system of claim 5 , wherein the heat exchanger is configured to evacuate the fluid from the respective reaction chamber.
7. The system of claim 4 , wherein the heat exchanger comprises a means for generating steam.
8. The system of claim 4 , wherein the heat exchanger is configured to draw heat out of the respective reaction chamber when the temperature within the respective reaction chamber exceeds 2300° F.
9. The system of claim 1 , wherein the first reaction chamber is configured to increase a temperature of the first gas at the first inlet when a first inlet temperature, at the first inlet, approaches or drops below an autoignition temperature of the first fuel.
10. The system of claim 1 , wherein the second reaction chamber is configured to increase a temperature of the second gas at the second inlet when a second inlet temperature, at the second inlet, approaches or drops below an autoignition temperature of the second fuel.
11. The system of claim 1 , wherein the second reaction chamber is configured to mix the flue gas with the second gas when a second inlet temperature of the second gas at the second inlet approaches or drops below an autoignition temperature of the second fuel.
12. The system of claim 1 , further comprising a controller configured to direct the flue gas to the second reaction chamber based on at least one of (i) a second inlet temperature of the second gas at the second inlet and (ii) the internal temperature of the second reaction chamber.
13. The system of claim 1 , further comprising a turbine or a piston engine that receives gas from at least one of the reaction chambers.
14. The system of claim 13 , wherein the turbine receives gas from the second reaction chamber.
15. The system of claim 1 , further comprising a compressor that receives and compresses gas, comprising a fuel mixture, prior to introduction of the fuel mixture into at least one of the reaction chambers.
16. The system of claim 15 , wherein the compressor is configured to compress the second gas prior to introducing the second gas into the second reaction chamber.
17. A system for oxidizing fuel comprising:
a first reaction chamber with a first inlet and a first outlet, the first reaction chamber configured to receive a first gas comprising a first oxidizable fuel and air, the first reaction chamber configured to maintain a gradual oxidation process of the first fuel; and
a second reaction chamber with a second inlet and a second outlet, the second reaction chamber configured to receive only (i) flue gas consisting of heated product gas from oxidation of the first fuel in the first reaction chamber, into the second reaction chamber through the second inlet and (ii) a second gas consisting of a second oxidizable fuel, the second reaction chamber configured to maintain a gradual oxidation process of the second fuel;
wherein the first and second reaction chambers are configured to maintain an internal temperature in the respective reaction chambers below a flameout temperature of the respective fuel.
18. The system of claim 17 , wherein at least one of the first and second reaction chambers is configured to reduce the respective internal temperature when an adiabatic temperature within the respective reaction chamber approaches or exceeds the flameout temperature of the respective fuel.
19. The system of claim 18 , wherein at least one of first and second reaction chambers is configured to reduce the respective internal temperature by removing heat from the respective reaction chamber by a heat exchanger.
20. The system of claim 19 , wherein the heat exchanger comprises a means for generating steam.