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EP-4739954-A2 - HYBRID POWER GENERATION SYSTEM

EP4739954A2EP 4739954 A2EP4739954 A2EP 4739954A2EP-4739954-A2

Abstract

A hybrid power generation system in one embodiment comprises a green boiler containing a thermal mass composition operable to store thermal energy, a solar energy collection system which absorbs solar energy to heat a first working fluid and in turn the thermal mass composition, and a power generation system comprising a steam turbine coupled to an electric generator to produce electricity and a nuclear steam supply system which convert a second working fluid comprising water from liquid to steam. Steam output by the nuclear steam supply system flows through the green boiler and is heated by absorbing heat from the thermal mass composition to increase the enthalpy of the steam and concomitantly electric power output from the turbine-generator. The nuclear steam supply system and green boiler may be retrofit to replace existing fossil fuel steam generation systems while retaining the energy conversion part of the fossil power plant.

Inventors

  • SINGH, KRISHNA P.
  • GOSWAMI, DHARENDRA YOGI
  • RAMPALL, INDRESH

Assignees

  • Holtec International

Dates

Publication Date
20260513
Application Date
20240702

Claims (20)

  1. 1. A hybrid power generation system comprising: a thermal energy storage vessel defining an internal space containing a thermal mass composition operable to store thermal energy; a solar energy collection system comprising a first closed flow loop including a solar collector configured to absorb solar energy and heat a first working fluid to produce a heated first working fluid, the first closed flow loop configured to circulate the heated first working fluid through and heat the thermal mass composition in the thermal energy storage vessel; a power generation system comprising a steam turbine coupled to an electric generator to produce electricity, and a nuclear steam supply system configured to convert a second working fluid comprising water from a liquid to steam; a second closed flow loop fluidly coupling the nuclear steam supply system, the steam turbine, and the thermal energy storage vessel together; the second closed flow loop configured to circulate the steam produced by the nuclear steam supply system through the thermal energy storage vessel to absorb thermal energy from the thermal mass composition and heat the steam which flows to the steam turbine.
  2. 2. The system according to claim 1, wherein the first closed flow loop is fluidly isolated from the second closed flow loop.
  3. 3. The system according to claim 1, wherein the power generation system comprises a condenser configured to condense the heated steam after leaving the steam turbine to form condensate, the second closed flow loop configured to flow the condensate to the nuclear steam supply system.
  4. 4. The system according to claim 3, wherein the second closed flow loop comprises a feedwater pump to pump the condensate to the nuclear steam supply system.
  5. 5. The system according to claims 3 or 4, wherein the nuclear steam supply system comprises a nuclear reactor and a steam generator fluidly coupled thereto, the reactor being configured to circulate a primary coolant through the steam generator to convert the condensate to steam.
  6. 6. The system according to claim 5, wherein the second closed flow loop further comprises a steam compressor disposed between the nuclear steam supply system and the thermal energy storage vessel in the second closed flow loop, the steam compressor operable raise the pressure of the steam exiting the nuclear steam supply system.
  7. 7. The system according to any one of claims 3-6, wherein the second closed flow loop further comprises a condensate bypass line which fluidly couples the condenser directly to the thermal energy storage vessel for bypassing the nuclear steam supply system.
  8. 8. The system according to claim 1, wherein the steam is heated in the thermal energy storage vessel to superheated conditions.
  9. 9. The system according to claim 2, wherein portions of the first and second closed flow loops each extend through the thermal energy storage vessel.
  10. 10. The system according to claim 9, wherein the first closed flow loop comprises a first plurality of first heat exchange tubes embedded in the thermal mass composition in the thermal energy storage vessel, and the second closed flow loop comprises a second plurality of second heat exchange tubes embedded in the thermal mass composition.
  11. 11. The system according to claim 10, wherein the first heat exchange tubes are spaced apart from the second heat exchanger tubes in the internal space of the thermal energy storage vessel.
  12. 12. The system according to claim 11, wherein the first heat exchange tubes transfer heat from the first working fluid to the thermal mass composition, and the second heat exchange tubes absorb heat from the thermal mass composition.
  13. 13. The system according to any one of claims 1-12, wherein the first working fluid is molten salt or heat transfer oil.
  14. 14. The system according to any one of claims 1-13, wherein the thermal mass composition comprises a mixture of a metallic material and a phase change material each in the form of solid particles at ambient temperature.
  15. 15. The system according to claim 14, wherein the metallic material has a higher melting temperature than the phase change material.
  16. 16. The system according to any one of claims 1-15, wherein the solar collector is a concentrated solar power unit comprising a plurality of heliostats each comprising a reflector and a centrally-located power tower comprising a plurality of thermal receivers which form a fluidic part of the first closed flow loop, the reflectors being operable to direct sunlight onto the thermal receivers to heat the first working fluid which flows through the thermal receivers.
  17. 17. The system according to claim 17, wherein each thermal receiver comprises a plurality of heat exchange tubes coupled between a top outlet header and a bottom inlet header, the first working fluid being flowable through the heat exchange tubes of the receiver.
  18. 18. The system according to claim 17, wherein the heat exchange tubes of each thermal receiver are arranged in tube walls including a pair of end tube walls obliquely angled with respect to each other, and an intermediate tube wall therebetween.
  19. 19. The system according to claim 18, wherein the thermal receivers are each generally C-shaped.
  20. 20. The system according to any one of claims 16-19, wherein the power tower comprises thermal receivers at multiple elevations.

Description

HYBRID POWER GENERATION SYSTEM CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the benefit of priority to U.S. Patent Application. No. 18/451,247 filed August 17, 2023, which claims the benefit of priority to U.S. Provisional Application No. 63/512,443 filed July 7, 2023; which are all incorporated herein by reference in their entireties. FIELD OF THE INVENTION [0002] The present invention relates to systems for producing electric power, and more particularly to a combined solar and nuclear power generation system which utilizes solar energy to boost the enthalpy of steam produced in nuclear steam supply system (NSSS) for generating electric power via the Rankine cycle. BACKGROUND OF THE INVENTION [0003] Thermal energy reaching earth from the sun is quite immense. Yet, harnessing it for useful purposes has been difficult. For over 200 years, fossil fuels excavated from the ground have been the mainstay for energy supply needed to support human civilization. Solar energy, although ubiquitous and visibly strong between the equatorial and subtropical regions of the earth (between the lines of Cancer and Capricorn), drew little attention until the late 20th century when the nexus between the carbon spewed into the environment by burning of fossil fuels and global climate disruption became impossible to ignore. Solar energy generation, long an object of scant scientific work, now has been vaulted into a central area of academic and industrial research. [0004] Nuclear power plants present an alternative power generation technology to solar which also does not contribute to carbon pollution. Small modular reactors (SMRs) have a small footprint and can be more readily sited than traditional large scale nuclear plants of the past. Such SMRs produce the steam necessary to generate power via a traditional Rankine cycle using a turbine-generator set (also referenced to as a turbogenerator in the art for short). However, these nuclear steam supply systems produce steam at a relatively modest pressure and temperature as shown in Table 1 below, thereby limiting the electric power output which can be extracted from the steam via the Rankine cycle. [0005] A system is needed which can boost the enthalpy of steam produced by SMRs in an environmentally benign manner using renewable power such as solar or wind. Increasing the enthalpy of the steam supply, which is a property related to the internal energy of a system based on pressure and temperature, would enable the electric power output of the generating plant to be enhanced. SUMMARY OF THE INVENTION [0006] A hybrid power generation system and related methods are disclosed for increasing the enthalpy of the steam produced by the nuclear steam supply system (NSSS) by using intermittently available energy collected from renewables, such as wind and solar in particular. By increasing the temperature and pressure of the steam (i.e. enthalpy), the electric power output from the hybrid power generation system can be increased via the higher energy steam supply. In one embodiment disclosed herein, the hybrid power generation system combines solar energy and a nuclear steam supply system in a single power plant. The hybrid plant can serve as a base load power plant or one that is used as a peaking generating unit to meet increased intermittent load demands on the electric power grid. Also disclosed is a system and method for converting fossil fuel power plants to a “green” hybrid power generator system. [0007] The hybrid power generation system in one embodiment generally includes a solar energy collection system, a power generation system which may operate on the Rankine cycle, and a thermal energy storage system comprising a “green boiler” which in one embodiment may be formed by an intermediary thermal energy storage (TES) vessel. The solar energy collection system recirculates a first heat transfer working fluid (“first working fluid” for short) in a first closed flow loop between the solar collector and the TES vessel to transfer captured solar heat or thermal energy to a thermal mass composition contained in the TES vessel which is operable to absorb and store the heat. [0008] The power generation system may operate on steam in one embodiment and includes a steam turbine-generator set operable to produce electric power in a conventional manner. The turbine-generator set may form part of a Rankine steam to electric power generation cycle. [0009] In one embodiment, the power generation system includes a NSSS which includes a nuclear reactor and associated steam generator which generates steam from a second heat transfer working fluid (“second working fluid” for short) which may be water for the Rankine cycle. The power generation system comprises a second closed flow loop which recirculates the second heat transfer working fluid (“second working fluid” for short) through the NSSS, steam turbine, and thermal energy storage vessel. The NSSS heats an