Semiclosed Brayton cycle power system with direct heat transfer

• US 7,937,930 B1
• Filed: 08/07/1992
• Issued: 05/10/2011
• Est. Priority Date: 08/07/1992
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Dunn, Paul M.
• Primary Examiner(s): Ellis; Christopher P
• Application Number:
  US07/926,199
• Time in Patent Office: 6,850 Days
• Field of Search: 60/390.2, 60/390.5, 60/394.61, 60/395.11, 607/27
• US Class Current: 60/39.511
• CPC Class Codes: F02C 3/24 the fuel or oxidant being liquid at standard temperature and pressure
• CPC Class Codes: F02C 7/10 by means of regenerative heat-exchangers

Abstract

A semiclosed power system utilizing a Brayton cycle with combustion occurring between diesel fuel and O₂ in direct contact with an inert gas. The inert gas and products of combustion form a heated working fluid which is expanded in a turbine to provide power. The expanded working fluid is then used in a regenerator to heat the cooler, compressed inert gas before the inert gas is transferred to the combustor. The expanded working fluid is cooled by direct contact with seawater causing the steam within the expanded working fluid to condense to water and CO₂ in the working fluid to be dissolved in the water and seawater. The inert gas is separated from the fluids and recycled within the system. The fluids are pumped overboard.

Claims

1. A semiclosed Brayton cycle power system comprising:

a storage tank/separator containing an inert gas;

a compressor connected to said storage tank/separator to receive and compress said inert gas;

a regenerator connected to said compressor to receive and to partially heat said compressed inert gas;

an O₂ source connected with said regenerator to mix O₂ from said O₂ source with said partially heated, compressed inert gas from said regenerator;

a diesel fuel tank for providing diesel fuel;

a combustor connected to said regenerator and said O₂ source for receiving a mixture of partially heated inert gas and O₂, and connected to said diesel fuel tank for receiving diesel fuel, said combustor providing through combustion a heated working fluid mixture of steam, inert gas and CO₂;

a turbine in communication with said combustor for receiving and expanding said heated working fluid;

a power transfer means connected between said turbine and said compressor, said transfer means enabling said turbine to drive said compressor;

said regenerator being connected to said turbine for receiving said expanded working fluid and utilizing said expanded working fluid for said partial heating of said inert gas;

a spray cooler/condenser connected to said regenerator for receiving seawater and said expanded working fluid and cooling said expanded working fluid by direct application of said seawater to said expanded working fluid, said steam in said expanded working fluid condensing to water and mixing with said seawater, said carbon dioxide in said expanded working fluid dissolving in said water and seawater, and said inert gas in said expanded working fluid remaining in the gaseous state; and

said storage tank/separator being connected to said spray cooler/condenser for receiving said inert gas and said mixture of seawater, water and carbon dioxide, and said storage tank further connected for discharging said mixture of seawater, water and carbon dioxide.

2. A semiclosed Brayton cycle power system according to claim 1 further comprising:

an auxiliary compressor connected to be driven by said turbine, said auxiliary compressor further connected for removing and further compressing a preselected portion of said inert gas from said compressor; and

an accumulator connected to said auxiliary compressor for receiving said inert gas compressed by said auxiliary compressor.

3. A semiclosed Brayton cycle power system according to claim 2 further comprising:

said compressor being connected to said accumulator for receiving inert gas from said accumulator; and

a pressure reducing valve connected between said accumulator and said compressor with said accumulator being on the higher pressure side of said pressure reducing valve.

4. A semiclosed Brayton cycle power system according to claim 3 further comprising a flow through valve located between said auxiliary compressor and said accumulator for preventing backflow from said accumulator through said auxiliary compressor.

5. A Brayton cycle process comprising the steps of:

supplying inert gas from a supply tank/separator to a compressor;

compressing said inert gas in said compressor;

preheating said compressed inert gas in a regenerator;

mixing said heated compressed inert gas with oxygen;

combusting said oxygen in said oxygen and heated inert gas mixture with diesel fuel in a combustor to form a hot high pressure steam, carbon dioxide, and inert gas working fluid;

expanding said hot, high pressure working fluid in a turbine to extract energy therefrom;

supplying said hot, expanded working fluid to said regenerator for preheating said inert gas;

cooling said hot, expanded working fluid by mixing said working fluid with seawater to form a liquid and said inert gas, said carbon dioxide being dissolved in said liquid;

separating said liquid from said inert gas in said storage tank/separator;

recirculating said inert gas; and

pumping said separated liquid from said storage tank/separator from said cycle.

6. A Brayton cycle process according to claim 5 comprising the additional step of removing a portion of said inert gas from said compressor to an accumulator.

7. A Brayton cycle process according to claim 6 comprising the additional steps of:

removing said inert gas from said accumulator;

expanding said removed inert gas; and

forwarding said expanded, removed inert gas to said compressor.