Power plants – Motive fluid energized by externally applied heat – Process of power production or system operation
Reexamination Certificate
2000-01-14
2001-03-06
Nguyen, Hoang (Department: 3748)
Power plants
Motive fluid energized by externally applied heat
Process of power production or system operation
C060S682000
Reexamination Certificate
active
06196000
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a power plant or system, and more particularly, to a low-emission, fossil fuel power plant with enhanced thermodynamic efficiency and pollution control.
In power plants, such as fossil fuel power plants, a fossil fuel is ignited and burned, oxidized or combusted within a reaction or combustion chamber under controlled conditions to generate heat. The heat is transferred to a circulating fluid, such as water, which flows through cooling tubes found in or adjacent to the reaction chamber, to generate steam. The steam is then passed through a steam turbine to generate electricity. Thermodynamic efficiency and pollution control have been and remain important considerations in the design of fossil fuel power plants. Conservation concerns, increasing fuel prices, and increasingly stringent pollution control standards are just a few of the factors that are requiring better, cleaner, more efficient ways of converting fossil fuels to electricity. Power plants or systems have achieved relatively high levels of efficiency and pollution control, but they are not without problems. For example, as effluent particulate standards have become increasingly difficult to meet, power plants have typically required a number of different processes and pieces of equipment to remove particulate matter. This adds to the cost and complexity of the system, and these processes and pieces of equipment typically require substantial power input, leading to substantial parasitic power losses and inefficiencies. Further, although power plants have occasionally used economizers and similar equipment to recover a portion of the sensible heat from the gases in the products of combustion, power plants have not attempted to recover the latent heat of vaporization of such gases because, under operating conditions of such plants, the condensation temperatures of such gases are too low to be efficiently recovered. Particularly in a system in which a relatively large amount of gaseous water is produced during combustion, the failure to recover any significant portion of such latent heat of vaporization can lead to significant thermodynamic inefficiencies.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an integrated power plant or system that recovers the latent heat of vaporization from produced water, scrubs out acid gases, removes chemical pollutants such as mercury and particulates, and condenses and recovers liquid carbon dioxide as an integral part of an over-all process.
It is a further object of the present invention to provide a power plant or system offering enhanced thermodynamic efficiency.
It is a further object of the present invention to provide a system of the above type that provides for enhanced pollution control.
It is a still further object of the present invention to provide a system of the above type that offers increased flexibility.
It is a still further object of the present invention to provide a system of the above type that allows one to recover at least a portion of the latent heat of vaporization of water produced during oxidation or combustion.
It is a still further object of the present invention to provide a system of the above type that operates at an elevated pressure making it thermodynamically practical to recover at least a portion of the latent heat of vaporization of water produced during oxidation or combustion.
It is a still further object of the present invention to provide a system of the above type that takes advantage of the useful properties of carbon dioxide.
It is a still further object of the present invention to provide a system of the above type that uses recycled, recovered water produced during oxidation or combustion to provide for reduced equipment costs and reduced equipment wear.
It is a still further object of the present invention to provide a system of the above type that uses a two-stage pressure step-up of the coolant to reduce heat exchanger equipment costs and reduce heat exchanger wear.
It is a still further object of the present invention to provide a system of the above type that provides for the efficient recovery of carbon dioxide for later use or sale.
It is a still further object of the present invention to provide a system of the above type that provides for improved removal of particulate matter from products of oxidation or combustion.
Toward the fulfillment of these and other objects and advantages, an elevated pressure power plant or system is disclosed that provides for cleanly and efficiently oxidizing or combusting a fuel, such as a fossil fuel, as follows. The fuel and an oxidant are passed to a reaction chamber, and the fuel is oxidized in the chamber at a pressure that is preferably substantially within a range of from approximately 700 psia to approximately 2000 psia and that is more preferably substantially within a range of from approximately 850 psia to approximately 1276 psia. A coolant is passed to the reaction chamber in a heat exchange relationship with the fuel and oxidant. The pressure of the reaction chamber is selected so that it is greater than or equal to a liquid-vapor equilibrium pressure of carbon dioxide at the temperature at which the power plant can reject heat to the environment. Products of combustion from the chamber may be passed to a heat exchanger, and water may be condensed from the products of combustion in the heat exchanger at a pressure that is preferably substantially within a range of from approximately 700 psia to approximately 2000 psia and that is more preferably substantially within a range of from approximately 850 psia to approximately 1276 psia. A portion of the condensed water may be recycled to the products of combustion upstream of the heat exchanger. Also, before being passed to the reaction chamber, the coolant may be routed through the heat exchanger in a two-step pressure fashion so that the coolant passes to the heat exchanger at a pressure substantially within a range of from approximately 300 psia to approximately 600 psia and passes to the reaction chamber at a pressure substantially within a range of from approximately 2000 psia to approximately 5000 psia.
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Nguyen Hoang
Rogers Mark A.
Speed Gary N.
Thermo Energy Power Systems, LLC
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