Systems and methods for steam reheat in power plants

Patent metadata

Field	Value
Publication number	US-11525374-B2
Application number	US-202016914418-A
Country	US
Kind code	B2
Filing date	Jun 28, 2020
Priority date	Dec 28, 2017
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Steam generators in power plants exchange energy from a primary medium to a secondary medium for energy extraction. Steam generators include one or more primary conduits and one or more secondary conduits. The conduits do not intermix the mediums and may thus discriminate among different fluid sources and destinations. One conduit may boil feedwater while another reheats steam for use in lower and higher-pressure turbines, respectively. Valves and other selectors divert steam and/or water into the steam generator or to other turbines or the environment for load balancing and other operational characteristics. Conduits circulate around an interior perimeter of the steam generator immersed in the primary medium and may have different cross-sections, radii, and internal structures depending on contained. A water conduit may have less flow area and a tighter coil radius. A steam conduit may include a swirler and rivulet stopper to intermix water in any steam flow.

First claim

What is claimed is:

1. A heat exchanger for transferring energy among multiple sources in a power generation plant, the heat exchanger comprising:
a primary inlet;
a primary outlet, wherein the primary inlet and the primary outlet are configured to join to different ends of a heat source separate from the heat exchanger so as to form a loop for a primary heat exchange fluid through the heat source and the heat exchanger;
a first secondary conduit inside the heat exchanger configured to directly contact the primary heat exchange fluid flowing through the heat exchanger, wherein the first secondary conduit includes a plurality of first heat exchange tubes configured to carry a secondary heat exchange fluid; and
a second secondary conduit separate from the first secondary conduit inside the heat exchanger, wherein the second secondary conduit is configured to directly contact the primary heat exchange fluid flowing through the heat exchanger and includes a plurality of second heat exchange tubes configured to carry the secondary heat exchange fluid having a different energy from the secondary heat exchange fluid in the first heat exchange tubes, and wherein the first heat exchange tubes have a different flow area from the second heat exchange tubes.

2. The heat exchanger of claim 1 , wherein the first heat exchange tubes have a first internal diameter and a first helical curvature, and wherein the second heat exchange tubes have a second internal diameter and a second helical curvature distinct from the first internal diameter and the first helical curvature.

3. The heat exchanger of claim 2 , wherein the first secondary conduit includes a first inlet and outlet, wherein the second secondary conduit includes a second inlet and outlet, and wherein the first inlet and outlet and second inlet and outlet are entirely distinct from one another on ends of the heat exchanger.

4. The heat exchanger of claim 2 , wherein the second internal diameter is approximately 50% to 100% larger than the first internal diameter, and wherein the second helical curvature is larger than the first helical curvature, and wherein there are at least twice as many first secondary conduits as the second secondary conduit.

5. The heat exchanger of claim 4 , wherein the first secondary conduit and the second secondary conduit are at a same axial level such that the first secondary conduit is more central to the heat exchanger than the second secondary conduit.

6. The heat exchanger of claim 2 , further comprising:
two more of the first secondary conduits and two more of the second secondary conduits so as to include at least three of the first secondary conduits and three of the second secondary conduits.

7. The heat exchanger of claim 1 , wherein the second secondary conduit includes a swirler fixed to an internal wall of the conduit so as to swirl a secondary heat exchange fluid flowing through the second secondary conduit.

8. The heat exchanger of claim 1 , wherein the second secondary conduit includes a rivulet stopper extending inward toward a center of the helical path so as to break up rivulets in a secondary heat exchange fluid flowing through the second secondary conduit.

9. The heat exchanger of claim 1 , wherein the first secondary conduit includes a plurality of flow dividers and a single inlet so as to separate a secondary heat exchange fluid into the first heat exchange tubes.

10. A power generation plant including:
a heat source heating a primary heat exchange fluid;
a first turbine extracting energy from a secondary heat exchange fluid; and
a steam generator for transferring energy among the primary and the secondary heat exchange fluids in the power generation plant, the steam generator including,
a primary inlet,
a primary outlet, wherein the primary inlet and the primary outlet join to different ends of the heat source so as to form a loop for the primary heat exchange fluid through the heat source and the steam generator,
a first secondary conduit inside the steam generator configured to directly contact the primary heat exchange fluid flowing through the steam generator, wherein the first secondary conduit includes a plurality of first heat exchange tubes configured to carry the secondary heat exchange fluid, and wherein the first secondary conduit includes a first secondary outlet joined to the first turbine, and
a second secondary conduit inside the steam generator entirely separate from the first secondary conduit and configured to directly contact the primary heat exchange fluid flowing through the steam generator, wherein the second secondary conduit includes a plurality of second heat exchange tubes configured to carry the secondary heat exchange fluid having a different energy from the secondary heat exchange fluid in the first heat exchange tubes, and wherein the first heat exchange tubes have a different flow area from the second heat exchange tubes.

11. The plant of claim 10 , wherein the first heat exchange tubes have a first internal diameter and a first helical curvature, and wherein the second heat exchange tubes have a second internal diameter and a second helical curvature distinct from the first internal diameter and the first helical curvature.

12. The plant of claim 11 , wherein the first secondary conduit further includes a first secondary inlet, wherein the second secondary conduit includes a second secondary inlet and outlet, and wherein the first secondary inlet and outlet and second secondary inlet and outlet are entirely distinct from one another on ends of the steam generator.

13. The plant of claim 12 , further comprising:
a condensed water feed, wherein the first secondary inlet is connected to the condensed water feed, wherein the first secondary conduit is configured to contain and boil water from the feed into superheated steam, wherein the second secondary inlet is connected to a steam outlet of the first turbine, and wherein the second secondary conduit is configured to contain and reheat steam from the steam outlet.

14. The plant of claim 13 , further comprising:
a second turbine having a lower operating pressure than the first turbine, wherein the second secondary outlet is connected to and provides the reheated steam to the second turbine, and wherein the first secondary outlet is connected to and provides the superheated steam to the first turbine.

15. The plant of claim 14 , further comprising:
a valve between the steam outlet of the first turbine, the second turbine, and the second secondary inlet, wherein the valve is operable to redirect steam from the steam outlet to the second turbine and the second secondary inlet in desired proportions.

16. The plant of claim 11 , wherein the primary heat exchange fluid is liquid sodium, wherein the heat source is a fast nuclear reactor, and wherein the secondary heat exchange fluid is liquid and/or gaseous water.

17. The plant of claim 11 , wherein the second internal diameter is approximately 50% to 100% larger than the first internal diameter, and wherein the second helical curvature is larger than the first helical curvature, and wherein there are at least twice as many first secondary conduits as the second secondary conduit.

18. The plant of claim 11 , wherein the steam generator further includes,
two more of the first secondary conduits and two more of the second secondary conduits so as to include at least three of the first secondary conduits and three of the second secondary conduits.

19. The plant of claim 10 , wherein the second secondary conduit inc

Assignees

• Ge Hitachi Nuclear Energy Americas Llc

Inventors

• Loewen Eric P
• Rasmussen Scott E

Classifications

• F01K7/44

  Use of steam for feed-water heating and another purpose · CPC title

• G21D1/006

  primary side of steam generators (secondary side of steam generators F22B1/00, F22B35/00 or F22B37/00) · CPC title

• F22B1/023

  with heating tubes for nuclear reactors, as long as they are not classified according to a specified heating fluid, in another group · CPC title

• G21D5/12

  Liquid working medium vaporised by reactor coolant · CPC title

• F01K7/38 Primary

  the engines being of turbine type · CPC title