Gradual oxidation with reciprocating engine
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 split cycle reciprocating engine, comprising:
an intake that receives an air-fuel mixture, the mixture comprising a mixture of air and a gas fuel;
a compression chamber, coupled to the reciprocating engine that compresses the mixture in a reciprocating piston chamber, the compression chamber comprising a first outlet;
an oxidation chamber that is configured to receive the mixture from the first outlet of the compression chamber via a first inlet and to maintain oxidation of the mixture at an internal temperature beneath a flameout temperature of the mixture and sufficient to oxidize the mixture without a catalyst, the oxidation chamber comprising a second outlet;
an expansion chamber, that receives oxidation product gas from the second outlet of the oxidation chamber and expands the product gas within the expansion chamber via a reciprocating piston;
a detection module that determines the internal temperature within the reaction chamber; and
a correction module that outputs instructions to reduce the internal temperature within the reaction chamber when an adiabatic temperature within the reaction chamber exceeds the flameout temperature of the fuel.
2. The system of claim 1 , wherein the oxidation chamber is configured to maintain an inlet temperature of the mixture above an autoignition temperature of the mixture.
3. The system of claim 1 , further comprising a heat exchanger that is configured to draw heat from the product gas and heat the mixture prior to introducing the mixture into the oxidation chamber.
4. The system of claim 3 , wherein the heat exchanger comprises a tube-in-tube heat exchanger.
5. The system of claim 1 , further comprising a heat exchange media disposed within the oxidation chamber.
6. The system of claim 5 , wherein the media is configured to maintain the internal temperature of the oxidation chamber below the flameout temperature by conducting heat toward the inlet of the oxidation chamber, and wherein media at the inlet of the oxidation chamber is cooled by the mixture being introduced into the oxidation chamber.
7. The system of claim 1 , wherein the fuel 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. A split cycle reciprocating engine, comprising:
a reciprocation cycle comprising (i) at least one compression chamber having therein a reciprocating piston and (ii) at least one expansion chamber having therein a reciprocating piston;
a heating cycle comprising (i) an intake that receives a gas air-fuel mixture comprising a mixture of air and a gas fuel, the intake being configured to direct the mixture to the compression chamber; (ii) a reaction chamber, disposed along a flow path between the at least one compression chamber and the at least one expansion chamber and configured to receive the mixture from the compression chamber and to maintain oxidation of the mixture at an internal reaction chamber temperature sufficient to oxidize the mixture without a catalyst; wherein the expansion chamber is configured to receive oxidation product gas from the reaction chamber and to expand the product gas within the expansion chamber via the reciprocating piston;
a detection module that detects the internal reaction chamber temperature; and
a correction module that outputs instructions, based on the detection module, to change at least one of (i) a chamber residence time of the mixture within the reaction chamber and (ii) an autoignition delay time within the reaction chamber sufficient for the mixture to autoignite and oxidize while within the reaction chamber and such that the mixture passes through a flammability area during a flammability residence time, less than the autoignition delay time.
9. The system of claim 8 , wherein the reaction chamber comprises an inlet, and the reaction chamber is configured to maintain an inlet temperature of the mixture at the inlet above an autoignition temperature of the mixture.
10. The system of claim 8 , further comprising a heat exchanger that is configured to draw heat from product gases of the reaction chamber and heat the mixture prior to introducing the mixture into the reaction chamber.
11. The system of claim 10 , wherein the heat exchanger comprises a tube-in-tube heat exchanger.
12. The system of claim 10 , wherein the product gases are directed back into the reaction chamber and combined with the air-fuel mixture introduced into the reaction chamber.
13. The system of claim 8 , further comprising a heat exchange media disposed within the reaction chamber.
14. The system of claim 13 , wherein the media is configured to maintain the internal temperature of the reaction chamber below a flameout temperature of the mixture by conducting heat toward an inlet of the reaction chamber, and wherein media at the inlet of the oxidation chamber is cooled by the mixture being introduced into the oxidation chamber.
15. The system of claim 8 , wherein the fuel 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.