ENHANCING POWER CYCLE EFFICIENCY FOR A SUPERCRITICAL BRAYTON CYCLE POWER SYSTEM USING TUNABLE SUPERCRITICAL GAS MIXTURES

• US 20130033044A1
• Filed: 08/05/2011
• Published: 02/07/2013
• Est. Priority Date: 08/05/2011
• Status: Active Grant

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Inventors: Pickard, Paul S., Vernon, Milton E., Wright, Steven A., Radel, Ross F.
• Granted Patent: US 9,745,899 B2
• Time in Patent Office: Days
• US Class Current: 290/1.R
• CPC Class Codes: F01K 25/08 using special vapours
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F01K 7/32 the engines using steam of critical or overcritical pressure
• CPC Class Codes: F02C 1/10 Closed cycles
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F22B 29/026 operating at critical or supercritical pressure
• CPC Class Codes: F22B 3/08 at critical or supercritical pressure values
• CPC Class Codes: F22B 35/086 operating at critical or supercritical pressure
• CPC Class Codes: Y02E 10/46 Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines

Abstract

Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

Claims

1. A supercritical Brayton cycle power generation system, comprising:

a heat source that comprises an inlet port and an outlet port, the heat source heating a fluid in the supercritical Brayton cycle power generation system, the fluid being a mixture that causes the fluid to have a supercritical temperature that is optimized for at least one environmental condition pertaining to the Brayton cycle power generation system;

a first turbine that comprises an inlet port and an outlet port;

first piping that operably couples the heat source with the inlet port of the first turbine, the first piping including the fluid;

a heat rejector that comprises an inlet port and an outlet port, the heat rejector rejecting heat near the supercritical temperature of the fluid;

second piping that operably couples the outlet port of the first turbine with the inlet port of the heat rejector, the second piping including the fluid;

a compressor having an inlet port and an outlet port;

third piping that operably couples the outlet port of the heat rejector with the inlet port of the compressor, the fluid travelling from the heat rejector to the compressor by way of the third piping;

a generator that generates electric power;

a rotating shaft that couples the first turbine with the generator, wherein rotation of the shaft causes the generator to generate the electric power; and

fourth piping that operably couples the outlet port of the compressor with the inlet port of the heat source, wherein the fluid travels from the compressor to the heat source by way of the fourth piping.

2. The supercritical Brayton cycle power generation system of claim 1, wherein the mixture comprises CO₂ and at least one other element or compound.

3. The supercritical Brayton cycle power generation system of claim 2, wherein the at least one other element or compound is an Alkane.

4. The supercritical Brayton cycle power generation system of claim 3, wherein the Alkane is one of Butane, Methane, Propane, or Hexane.

5. The supercritical Brayton cycle power generation system of claim 2, wherein the at least one other element or compound is Helium, Neon, or Nitrogen.

6. The supercritical Brayton cycle power generation system of claim 2, wherein a molar concentration of the at least one other element or compound in the mixture is less than 10 percent.

7. The supercritical Brayton cycle power generation system of claim 6, wherein the molar concentration of the at least one other element or compound in the mixture is less than 5 percent.

8. The supercritical Brayton cycle power generation system of claim 1, further comprising:

a sensor that senses the at least one environmental condition pertaining to the Brayton cycle power generation system; and

an actuator that is caused to dynamically alter a composition of the mixture based at least in part upon the at least one environmental condition.

9. The supercritical Brayton cycle power generation system of claim 8, further comprising a composition modifier module that is controlled by the actuator to cause the composition of the mixture to be dynamically altered based at least in part upon the at least one environmental condition.

10. The supercritical Brayton cycle power generation system of claim 9, wherein the composition modifier module comprises a condenser that condenses an element or compound in the mixture for extraction from the mixture.

11. The supercritical Brayton cycle power generation system of claim 8, wherein the at least one environmental condition is ambient temperature pertaining to the supercritical Brayton cycle power generation system.

12. The supercritical Brayton cycle power generation system of claim 8, wherein the at least one environmental condition is barometric pressure in an environment of the supercritical Brayton cycle power generation system.

13. The supercritical Brayton cycle power generation system of claim 1, further comprising:

a recompressor comprising an inlet port and an outlet port;

fifth piping that couples the inlet port of the recompressor with the second piping such that the fluid travels from the first turbine to the recompressor by way of the second piping and the fifth piping; and

sixth piping that couples the outlet port of the recompressor with the fourth piping such that the fluid travels from the recompressor to the first turbine by way of the sixth piping and the fourth piping.

14. The supercritical Brayton cycle power generation system of claim 1 being an intercooled power generation system.

15. The supercritical Brayton cycle power generation system of claim 1, wherein the heat source is a geothermal heat source.

16. A method, comprising:

receiving first data from a sensor that is indicative of at least one environmental condition pertaining to a supercritical Brayton cycle power generation system;

computing a first desired critical, temperature of a fluid that flows through the supercritical Brayton cycle power generation system based at least in part upon the first data from the sensor;

causing a processor to compute a first composition of the fluid such that the fluid has the first desired critical temperature; and

operating the Brayton cycle power generation system with the fluid of the first composition computed by the processor.

17. The method of claim 16, wherein the composition of the fluid comprises at least 90% CO₂ by molar concentration.

18. The method of claim 17, wherein the composition of the fluid additionally comprises an Alkane.

19. The method of claim 16, further comprising:

receiving second data from the sensor that is indicative of the at least one environmental condition pertaining to the supercritical Brayton cycle power generation system;

computing a second desired critical temperature of the fluid based at least in part upon the second data from the sensor;

causing the processor to compute a second composition of the fluid such that the fluid has the second desired critical temperature;

dynamically changing concentration of a compound or element in the fluid to cause a composition of the fluid to change from the first composition to the second composition as the supercritical Brayton cycle power generation system is generating electric power.

20. A supercritical Brayton cycle power generation system, comprising:

compressor means for compressing a fluid that travels through the supercritical Brayton cycle power generation system, the fluid having a composition that is selected based at least in part upon a desired supercritical temperature of the fluid, the desired supercritical temperature of the fluid based at least in part upon an environmental parameter corresponding to the supercritical Brayton cycle power generation system, the composition comprising CO₂ and an Alkane;

turbine means that receives the fluid compressed by the compressor means and rotates a shaft;

generator means that is coupled to the shaft and generates electric power based at least in part upon rotational velocity of the shaft;

piping means for transporting the fluid between the turbine means and the compressor means; and

heat rejection means for rejecting heat in the piping means at a temperature that is within 10% of the desired supercritical temperature of the fluid.