Gradual oxidation and multiple flow paths
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. An oxidizer comprising:
a reaction chamber having an inlet and an outlet, the inlet configured to accept a gas mixture comprising a low-energy-content (LEC) fuel and at least one of the group of a high-energy-content (HEC) fuel, an oxidant-comprising (OC) gas, and a diluent-containing (DC) gas, the gas mixture being at an initial temperature below an autoignition temperature of the gas mixture;
a heat exchange media disposed within the reaction chamber;
a first flow path from the inlet, the first flow path being connected to the inlet and passing through the media, which is hotter than the autoignition temperature of the mixture, until the mixture reaches a temperature above the autoignition temperature of the gas mixture, and a second flow path, following the first flow path, the second flow path being connected to the outlet, the second flow path being generally opposite to the first flow path;
a controller, comprising
a detection module that detects (i) an internal temperature of the reaction chamber and (ii) a reaction chamber inlet temperature of the fuel; and
a correction module that outputs instructions, based the internal temperature or the inlet temperature detected by the detection module, to control a speed at which the media circulates through the first flow path and the second flow path such that (i) an adiabatic temperature within the reaction chamber is maintained below a flameout temperature of the mixture and (ii) the reaction chamber inlet temperature is maintained above the autoignition temperature of the mixture.
2. The oxidizer of claim 1 , wherein the reaction chamber is configured to maintain oxidation of the gas mixture along at least one of the first and second flow paths without a catalyst.
3. The oxidizer of claim 1 , wherein the reaction chamber is configured to maintain oxidation of the mixture beneath the flameout temperature of the gas mixture by circulating heat exchange media outside the reaction chamber.
4. The oxidizer of claim 1 , further comprising at least one of a turbine or a piston engine that is configured to receive gas from the reaction chamber outlet and expand the gas.
5. The oxidizer of claim 1 , 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.
6. An oxidizer comprising:
a reaction chamber having an inlet and an outlet, the inlet configured to accept a gas mixture comprising a low-energy-content (LEC) fuel and at least one of the group of a high-energy-content (HEC) fuel gas, an oxidant-comprising (OC) gas, and a diluent-containing (DC) gas, the gas mixture being at a temperature below an autoignition temperature of the mixture;
a heat controller, comprising
a heat exchanger containing a heat exchange media;
a detection module that detects a temperature of the gas mixture; and
a correction module that outputs instructions (i) to increase a temperature of the gas mixture to at least an autoignition temperature of the mixture, thereby permitting the gas mixture to autoignite, and (ii) to maintain an adiabatic temperature within the reaction chamber below a flameout temperature while the autoignited gas mixture oxidizes; and
a first flow path from the inlet, the first flow path being configured to direct the mixture entering the inlet through the media, and a second flow path, following the first flow path, the second flow path being configured to direct the gas mixture to the outlet, the second flow path being generally opposite to the first flow path.
7. The oxidizer of claim 6 , wherein the heat exchanger is configured to raise the temperature of the mixture to at least the autoignition temperature.
8. The oxidizer of claim 7 , wherein the heat exchanger is positioned within the reaction chamber.
9. The oxidizer of claim 8 , wherein the heat exchanger is configured to heat the mixture to above the autoignition temperature after the mixture is within the reaction chamber.
10. The oxidizer of claim 6 , wherein the reaction chamber is configured to maintain oxidation of the mixture beneath a flameout temperature of the gas mixture without a catalyst.
11. The oxidizer of claim 6 , further comprising at least one of a turbine or a piston engine that receives gas from the reaction chamber and expands the gas.
12. The oxidizer of claim 6 , 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.
13. An oxidizer comprising:
a reaction chamber having an inlet and an outlet, the inlet configured to accept a first gas mixture comprising a low-energy-content (LEC) fuel and at least one of the group of a high-energy-content (HEC) fuel gas, an oxidant-comprising (OC) gas, and a diluent-containing (DC) gas, the gas mixture being at an initial temperature below an autoignition temperature of the mixture;
a heat controller, comprising
a heat exchanger containing a heat exchange media;
a detection module that detects a temperature of the gas mixture; and
a correction module that outputs instructions (i) to heat the first gas mixture to at least an autoignition temperature of the first gas mixture, such that the first gas mixture autoignites and (ii) to maintain an adiabatic temperature within the reaction chamber below a flameout temperature; and
an injector that is configured to inject, after the first gas mixture is heated to at least the autoignition temperature, a second gas mixture comprising a LEC fuel gas and a HEC fuel, wherein the injector injects a ratio of the LEC and HEC gas to form the second gas mixture at a rate of injection that is selected to produce substantially the same ratio of LEC and HEC gas to the second mixture as a ratio of the LEC gas and the at least one of high-energy-content (HEC) fuel gas, an oxidant-comprising (OC) gas, and a diluent-containing (DC) gas to the first gas mixture;
wherein the reaction chamber is configured (i) to mix the injected second gas into the autoignited first gas mixture at a rate to produce a substantially homogeneous third gas mixture in a time less than the autoignition delay time for the second gas mixture and (ii) to maintain a temperature of the first gas mixture below a flameout temperature while the autoignited first gas mixture oxidizes;
a first flow path from the inlet, the first flow path being configured to direct the mixture entering the inlet through the media, and a second flow path, following the first flow path, the second flow path being configured to direct the gas mixture to the outlet, the second flow path being generally opposite to the first flow path.
14. The oxidizer of claim 13 , wherein the heat exchanger is configured to raise the temperature of the mixture to at least the autoignition temperature.
15. The oxidizer of claim 14 , wherein the heat exchanger is positioned within the reaction chamber.
16. The oxidizer of claim 13 , wherein the reaction chamber is configured to maintain oxidation of the first gas mixture within the reaction chamber without a catalyst.
17. The oxidizer of claim 13 , wherein the reaction chamber is configured to maintain oxidation of the second gas mixture beneath a flameout temperature of the gas mixture without a catalyst.
18. The oxidizer of claim 13 , further comprising at least one of a turbine or a piston engine that is configured to receive gas from the reaction chamber and to expand the gas.
19. The oxidizer of claim 13 , wherein the first 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.