Combined Cycle Solar Power Generation

• US 20130147197A1
• Filed: 02/11/2013
• Published: 06/13/2013
• Est. Priority Date: 12/23/2009
• Status: Abandoned Application

• Current Assignee: Abu Dhabi Future Energy Company PJSC
• Original Assignee: Abu Dhabi Future Energy Company PJSC
• Inventors: Goebel, Olaf, Al Ali, Yousif
• Application Number:
  US13/764,441
• Publication Number:
  US 20130147197A1
• Time in Patent Office: Days
• US Class Current: 290/52
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F01K 3/00 Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein regenerating exhaust steam F01K19/00
• CPC Class Codes: F01K 3/12 having two or more accumulators
• CPC Class Codes: F02C 1/05 characterised by the type or source of heat, e.g. using nuclear or solar energy
• CPC Class Codes: F03G 6/04 gaseous F03G6/064, F03G6/068 take precedence
• CPC Class Codes: F03G 6/064 having a gas turbine cycle, i.e. compressor and gas turbine combination
• CPC Class Codes: F05D 2220/72 a steam turbine
• CPC Class Codes: F22B 1/006 using solar heat solar heat collectors per se F24S; devices for producing mechanical power from solar energy F03G6/00
• CPC Class Codes: F24S 20/20 Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
• CPC Class Codes: F28D 20/00 Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
• CPC Class Codes: F28D 2020/0047 using molten salts or liquid metals
• CPC Class Codes: H02K 7/1823 structurally associated with turbines or similar engines
• CPC Class Codes: Y02E 10/46 Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

Combined cycle solar power generation is achieved using a primary cycle based on a solar receiver, such as a volumetric absorber, in which compressed air is heated by concentrated solar radiation, coupled with a secondary cycle based on a water/steam circuit driven by exhaust gas from the primary cycle. When the primary cycle is inactive, typically at night time, the secondary cycle can be driven by accessing a heat store of liquid or solid heat storage material, such as a molten salt or concrete blocks, which has been heated earlier during day time operation. The water/steam circuit is reconfigurable between first and second switching conditions, wherein in the first switching condition heat is transferred directly or indirectly from the primary cycle to heat the heat storage material, and in the second switching condition stored heat is transferred from the heat storage material to the water/steam circuit in order to generate steam.

Claims

1. A combined cycle power plant based on a primary cycle and a secondary cycle, the primary cycle comprising:

a) a compressor having a gas inlet and being operable to compress the gas received from the gas inlet;

b) a solar receiver arranged to receive compressed gas from the compressor as well as concentrated solar radiation, the solar receiver comprising a gas passageway through which the compressed gas is passed and which is in thermal communication with the concentrated solar radiation, thereby to heat the gas; and

c) a gas turbine through which the heated gas is expanded to generate electricity;

the secondary cycle based on a water/steam circuit in which is arranged;

d) a heat recovery steam generator having a heat exchanger arranged to generate steam from the heated expanded gas from the primary cycle output from the gas turbine;

e) a steam turbine through which steam is expanded to generate electricity; and

f) a condenser for condensing steam from the steam turbine;

further comprising;

g) a heat storage circuit including a heat storage material, the heat storage circuit being reconfigurable between first and second switching conditions, wherein in the first switching condition heat is transferable from the primary cycle to heat the heat storage material, and in the second switching condition heat is transferable from the heat storage material to the water/steam circuit in order to generate steam.

2. The power plant of claim 1, further comprising a heliostat arranged to concentrate solar radiation onto the solar receiver.

3. The power plant of claim 1, further comprising an auxiliary fossil fuel burner arranged in the primary cycle to heat and compress the gas as an alternative to the solar receiver, thereby providing a hybrid primary cycle.

4. The power plant of claim 1, wherein the solar receiver comprises a volumetric absorber arranged to receive the concentrated solar radiation and in thermal communication with the gas passageway.

5. The power plant of claim 1, wherein the heat storage material comprises one or more solid blocks arranged in thermal communication with the heat storage circuit.

6. The power plant of claim 1, wherein the heat storage material comprises a liquid contained in the heat storage circuit.

7. The power plant of claim 5, wherein the heat storage circuit comprises a heat exchanger which in the first switching condition provides thermal contact between the heat storage material and steam in the secondary cycle, thereby to heat the heat storage material.

8. The power plant of claim 6, wherein the heat storage circuit comprises a heat exchanger which in the first switching condition provides thermal contact between the liquid heat storage material and hot gas from the primary cycle, thereby to heat the liquid heat storage material.

9. The power plant of claim 6, wherein the liquid heat storage circuit further comprises a cold storage tank and a hot storage tank, wherein in the first switching condition liquid heat storage material passes from the cold storage tank to the hot storage tank, and in the second switching condition liquid heat storage material passes from the hot storage tank to the cold storage tank.

10. The power plant of claim 6, wherein the liquid heat storage circuit further comprises a thermocline storage tank having a hot end and a cold end, wherein in the first switching condition liquid heat storage material is taken from the cold end of the storage tank and returned to the hot end of the storage tank, and in the second switching condition liquid heat storage material is taken from the hot end of the storage tank and is returned to the cold end of the storage tank.

11. A combined cycle method of generating electricity utilizing a first thermodynamic cycle operating in a first temperature range in combination with a second thermodynamic cycle operating in a second temperature range lower than the first temperature range,

wherein the first thermodynamic cycle is based on:

a) directing solar radiation onto a solar receiver;

b) supplying compressed gas to the solar receiver to heat the gas; and

c) expanding the heated gas to generate electricity;

wherein the second thermodynamic cycle is based on;

d) heating steam;

e) expanding the steam to generate electricity;

f) passing the steam through a condenser to liquefy it into water;

g) supplying the water onward for re-heating into steam;

further comprising a first mode of use to be operated during periods when the first thermodynamic cycle is active comprising;

i) heating the water in the second thermodynamic cycle into steam using the expanded gas from the first thermodynamic cycle so that the first thermodynamic cycle drives the second thermodynamic cycle; and

ii) heating a heat storage material using either steam from the second thermodynamic cycle, or gas from the first thermodynamic cycle, and then retaining the heated heat storage material for later use;

and a second mode of use to be operated during periods when the first thermodynamic cycle is inactive comprising;

iii) heating the steam using the heat storage material that was heated in the first mode of use, thereby to drive the second thermodynamic cycle when the first thermodynamic cycle is inactive.

12. The method of claim 11, further comprising a second mode of use with an alternate first thermodynamic cycle, wherein an auxiliary fossil fuel burner is operated as an alternative heat source to drive the first thermodynamic cycle, wherein the alternate first thermodynamic cycle comprises:

a′

) combusting fossil fuel in a burner;

b′

) using heat from the burner to heat compressed gas; and

c′

) expanding the heated gas to generate electricity.

13. The method of claim 11, wherein the solar receiver comprises a volumetric absorber arranged to receive the solar radiation and in thermal communication with the compressed gas.

14. The method of claim 11, wherein the heat storage material comprises one or more solid blocks.

15. The method of claim 11, wherein the heat storage material comprises a liquid.