DRIVEN STARTER PUMP AND START SEQUENCE

• US 20120131919A1
• Filed: 08/08/2011
• Published: 05/31/2012
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: Echogen Power Systems, LLC
• Original Assignee: Echogen Power Systems, LLC
• Inventors: Held, Timothy James, Vermeersch, Michael Louis, Xie, Tao
• Granted Patent: US 8,616,001 B2
• Time in Patent Office: Days
• US Class Current: 60/646
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 23/04 condensation heat from one cycle heating the fluid in another cycle
• CPC Class Codes: F01K 25/10 the vapours being cold, e.g. ammonia, carbon dioxide, ether
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F22B 35/086 operating at critical or supercritical pressure

Abstract

Various thermodynamic power-generating cycles are disclosed. A turbopump arranged in the cycles is started and ramped-up using a starter pump arranged in parallel with the main pump of the turbopump. Once the turbopump is able to self-sustain, a series of valves may be manipulated to deactivate the starter pump and direct additional working fluid to a power turbine for generating electrical power.

Claims

1. A heat engine system for converting thermal energy into mechanical energy, comprising:

a turbopump comprising a main pump operatively coupled to a drive turbine and arranged within a casing, the main pump being configured to circulate a working fluid throughout a working fluid circuit, wherein the working fluid is separated in the working fluid circuit into a first mass flow and a second mass flow;

a first heat exchanger in fluid communication with the main pump and in thermal communication with a heat source, the first heat exchanger being configured to receive the first mass flow and transfer thermal energy from the heat source to the first mass flow;

a power turbine fluidly coupled to the first heat exchanger and configured to expand the first mass flow;

a first recuperator fluidly coupled to the power turbine and configured to receive the first mass flow discharged from the power turbine;

a second recuperator fluidly coupled to the drive turbine, the drive turbine being configured to receive and expand the second mass flow and discharge the second mass flow into the second recuperator;

a starter pump arranged in parallel with the main pump in the working fluid circuit;

a first recirculation line fluidly coupling the main pump with a low pressure side of the working fluid circuit; and

a second recirculation line fluidly coupling the starter pump with the low pressure side of the working fluid circuit.

2. The system of claim 1, wherein the first recuperator transfers residual thermal energy from the first mass flow to the second mass flow before the second mass flow is expanded in the drive turbine.

3. The system of claim 1, wherein the first recuperator transfers residual thermal energy from the first mass flow discharged from the power turbine to the first mass flow directed to the first heat exchanger.

4. The system of claim 1, wherein the second recuperator transfers residual thermal energy from the second mass flow to a combination of the first and second mass flows.

5. The system of claim 1, further comprising a second heat exchanger arranged in series with the first heat exchanger and in thermal communication with the heat source, the second heat exchanger being in fluid communication with the main pump and the starter pump and configured to transfer thermal energy to the second mass flow.

6. The system of claim 5, wherein the second recuperator transfers residual thermal energy from the second mass flow discharged from the drive turbine to the second mass flow directed to the second heat exchanger.

7. The system of claim 1, wherein the working fluid is carbon dioxide.

8. The system of claim 1, wherein the main pump and drive turbine and hermetically-sealed within the casing.

9. The system of claim 1, further comprising:

a first bypass valve arranged in the first recirculation line; and

a second bypass valve arranged in the second recirculation line.

10. A method for starting a turbopump in a thermodynamic working fluid circuit, comprising:

circulating a working fluid in the working fluid circuit with a starter pump, the starter pump being in fluid communication with a first heat exchanger that is in thermal communication with a heat source;

transferring thermal energy to the working fluid from the heat source in the first heat exchanger;

expanding the working fluid in a drive turbine fluidly coupled to the first heat exchanger, the drive turbine being operatively coupled to a main pump, where the drive turbine and the main pump comprise the turbopump;

driving the main pump with the drive turbine;

diverting the working fluid discharged from the main pump into a first recirculation line fluidly communicating the main pump with a low pressure side of the working fluid circuit, the first recirculation line having a first bypass valve arranged therein;

closing the first bypass valve as the turbopump reaches a self-sustaining speed of operation;

circulating the working fluid discharged from the main pump through the working fluid circuit;

deactivating the starter pump and opening a second bypass valve arranged in a second recirculation line fluidly communicating the starter pump with the low pressure side of the working fluid circuit; and

diverting the working fluid discharged from the starter pump into the second recirculation line.

11. The method of claim 10, wherein circulating the working fluid in the working fluid circuit with the starter pump is preceded by closing a shut-off valve to divert the working fluid around a power turbine arranged in the working fluid circuit.

12. The method of claim 11, further comprising:

opening the shut-off valve once the turbopump reaches the self-sustaining speed of operation, thereby directing the working fluid into the power turbine;

expanding the working fluid in the power turbine; and

driving a generator operatively coupled to the power turbine to generate electrical power.

13. The method of claim 11, further comprising:

opening the shut-off valve once the turbopump reaches the self-sustaining speed of operation;

directing the working fluid into a second heat exchanger fluidly coupled to the power turbine and in thermal communication with the heat source;

transferring additional thermal energy from the heat source to the working fluid in the second heat exchanger;

expanding the working fluid received from the second heat exchanger in the power turbine; and

driving a generator operatively coupled to the power turbine, whereby the generator is operable to generate electrical power.

14. The method of claim 11, further comprising:

opening the shut-off valve once the turbopump reaches the self-sustaining speed of operation;

directing the working fluid into a second heat exchanger in thermal communication with the heat source, the first and second heat exchangers being arranged in series in the heat source;

directing the working fluid from the second heat exchanger into a third heat exchanger fluidly coupled to the power turbine and in thermal communication with the heat source, the first, second, and third heat exchangers being arranged in series in the heat source;

transferring additional thermal energy from the heat source to the working fluid in the third heat exchanger;

expanding the working fluid received from the third heat exchanger in the power turbine; and

driving a generator operatively coupled to the power turbine, whereby the generator is operable to generate electrical power.

15. A heat engine system for converting thermal energy into mechanical energy, comprising:

a turbopump including a main pump operatively coupled to a drive turbine and hermetically-sealed within a casing, the main pump being configured to circulate a working fluid throughout a working fluid circuit;

a starter pump arranged in parallel with the main pump in the working fluid circuit;

a first check valve arranged in the working fluid circuit downstream from the main pump;

a second check valve arranged in the working fluid circuit downstream from the starter pump and fluidly coupled to the first check valve;

a power turbine fluidly coupled to both the main pump and the starter pump;

a shut-off valve arranged in the working fluid circuit to divert the working fluid around the power turbine;

a first recirculation line fluidly coupling the main pump with a low pressure side of the working fluid circuit; and

a second recirculation line fluidly coupling the starter pump with the low pressure side of the working fluid circuit.

16. The system of claim 15, further comprising:

a first recuperator fluidly coupled to the power turbine; and

a second recuperator fluidly coupled to the drive turbine.

17. The system of claim 16, further comprising a third recuperator fluidly coupled to the second recuperator, the first, second, and third recuperators being arranged in series in the working fluid circuit.

18. The system of claim 15, further comprising a condenser fluidly coupled to both the main pump and the starter pump.

19. The system of claim 15, further comprising first, second, and third heat exchangers arranged in series in thermal communication with a heat source and in parallel within the working fluid circuit.

20. The system of claim 19, wherein the working fluid is carbon dioxide.