System and method for on-board waste heat recovery

1. A method, comprising:

receiving a hydrocarbon stream;

transferring heat from an exhaust stream of an internal combustion engine to the hydrocarbon stream;

reacting the hydrocarbon stream with a catalyst to produce hydrogen and modified hydrocarbons having a lower saturation state than the hydrocarbon stream;

separating the hydrogen and the modified hydrocarbons into a hydrogen stream and a modified hydrocarbon stream;

checking a catalyst activity value of the catalyst;

recycling a fraction of the hydrogen stream to a catalyst inlet that is dependent on the catalyst activity value, composition of the hydrocarbons, catalyst composition and operating temperature to slow the degradation of the catalyst; and

recovering an amount of energy from a remaining fraction of the hydrogen stream.

2. The method of claim 1 , further comprising returning the modified hydrocarbon stream to a fuel supply.

3. The method of claim 1 , wherein the recovering an amount of energy from the remaining fraction of the hydrogen comprises a recovery process selected from the recovery processes consisting of burning the hydrogen, reacting the hydrogen in a fuel cell, and storing the hydrogen.

4. The method of claim 1 , further comprising evaporating the hydrocarbon stream before the reacting.

5. The method of claim 1 , further comprising determining whether an activity of the catalyst has fallen below a threshold, and regenerating the catalyst in response to the activity of the catalyst falling below the threshold.

6. The method of claim 5 , wherein the regenerating the catalyst comprises flowing an oxygenated stream to the catalyst.

7. The method of claim 1 , further comprising commanding a first auxiliary heater to heat the hydrocarbon stream.

8. The method of claim 1 , further comprising commanding a second auxiliary heater to heat the catalyst.

9. A method, comprising:

receiving a hydrocarbon stream;

heating and evaporating the hydrocarbon stream;

reacting the hydrocarbon stream to provide hydrogen and modified hydrocarbon products comprising a lower saturation state than the hydrocarbon stream;

separating the hydrogen and modified hydrocarbon products into a modified hydrocarbon stream and a hydrogen stream; and

checking a catalyst activity value of the catalyst;

recycling a fraction of the hydrogen stream to a catalyst inlet that is dependent on the catalyst activity value, composition of the hydrocarbons, catalyst composition and operating temperature to slow the degradation of the catalyst; and

recovering energy from a remaining fraction of the hydrogen stream.

10. The method of claim 9 , further comprising determining whether a catalyst temperature is above a threshold and heating a catalyst in response to the catalyst temperature being below the threshold.

11. The method of claim 9 , further comprising recirculating the modified hydrocarbon stream to a fuel supply.

12. The method of claim 9 , wherein the recovering energy comprises generating power from the hydrogen stream.

13. The method of claim 9 , wherein the recovering energy comprises at least one energy recovery activity selected from the activities consisting of: generating power in a fuel cell, generating heat in a burner, recovering chemical energy of the hydrogen as kinetic energy, and storing the hydrogen as chemical potential energy.

14. The method of claim 9 , wherein the heating and evaporating the hydrocarbon stream comprises exchanging heat from an exhaust stream of an internal combustion engine to the hydrocarbon stream.

15. The method of claim 9 , wherein the hydrocarbon stream comprises fuel from a fuel supply for an internal combustion engine.

16. The method of claim 9 , wherein the hydrogen stream comprises a significant fraction of the hydrogen in the hydrocarbon stream.

17. The method of claim 9 , wherein the hydrogen stream comprises between 1% and 5% of the hydrogen in the hydrocarbon stream.