Installation and Methods for Storing and Methods for Storing and Restoring Electrical Energy Using a Piston-Type Gas Compression and Expansion Unit

• US 20100218500A1
• Filed: 10/03/2008
• Published: 09/02/2010
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Saipem SA (Saipem)
• Original Assignee: Saipem SA (Saipem)
• Inventors: Ruer, Jacques
• Granted Patent: US 8,443,605 B2
• Time in Patent Office: Days
• US Class Current: 60/659
• CPC Class Codes: F01K 25/00 Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
• CPC Class Codes: F01K 3/12 having two or more accumulators
• CPC Class Codes: F01K 7/36 the engines being of positive-displacement type
• CPC Class Codes: F02G 1/044 having at least two working members, e.g. pistons, delivering power output
• CPC Class Codes: F28D 17/02 using rigid bodies, e.g. of porous material
• CPC Class Codes: F28D 20/0056 using solid heat storage material F28D20/0052 takes precedence
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

The present invention relates to an installation and to methods for storing and returning electrical energy, comprising first and second lagged enclosures containing porous refractory material through which a gas is caused to flow by causing the gas to flow through first and second compression/expansion groups interposed in the pipe circuit between the top and bottom ends respectively of said first and second enclosures, each compression/expansion group comprising a piston moved in translation in a cylinder, each group operating in a different mode, either in compression mode or in expansion mode, one of the two compression/expansion groups receiving a gas at a temperature that is higher than the other group, such that in compression mode it is driven by an electric motor that consumes electrical energy for storage E₁, and in a thermodynamic engine mode it drives an electricity generator enabling the electrical energy (E_R) to be returned. The electrical energy is stored in the form of heat within masses of refractory substances, and said stored potential thermal energy is returned in the form of electrical energy.

Claims

1. An installation for storing and returning energy, the installation comprising:

A) a first lagged enclosure filled with a first porous refractory material suitable for passing a gas flowing through said first enclosure between top and bottom ends of said first enclosure; and

B) a second lagged enclosure filled with a second porous refractory material suitable for passing a gas flowing through said second enclosure between top and bottom ends of said second enclosure; and

C) lagged pipes enabling the gas to flow in a closed circuit between the two enclosures, the pipes comprising first and second top pipes between the top ends of the two enclosures and first and second bottom pipes between the bottom ends of the two enclosures; and

D) a gas compression and expansion unit comprising;

D1) at least one first gas compression/expansion group interposed between the top ends of said first and second enclosures to which it is connected by the first and second top pipes respectively, the group comprising a first piston suitable for being moved in translation in a first cylinder, said first gas compression/expansion group being coupled to an electric motor and an electricity generator, said first gas compression/expansion group being capable of operating;

either in compression mode, said first piston being moved in translation under drive from said electric motor powered by electrical energy for storage so as to compress in said first cylinder the gas coming from said top end of the second cylinder and send it to said top end of the first enclosure;

or else in expansion or “

thermodynamic engine”

mode, said piston being moved in translation by expansion in said first cylinder of the gas coming from said top end of the first enclosure to be sent to said top end of the second enclosure via said second top pipe, the movement of said first piston serving to drive said electricity generator and thus return the electrical energy; and

D2) at least one second gas compression/expansion group interposed between the bottom ends of said first and second enclosures to which it is connected by said first and second bottom pipes respectively, the group comprising a second piston suitable for being moved in translation in a second cylinder, the movement of said second piston being coupled to the movement of said first piston in such a manner that said second gas compression/expansion group is suitable for operating;

either in expansion or “

thermodynamic engine”

mode when said first compression/expansion group is operating in compression mode, in order to expand the gas coming from said bottom end of the first enclosure and sending it to said bottom end of the second enclosure;

or else in compression mode when said first compression/expansion group is operating in expansion mode, to compress the gas coming from said bottom end of the second enclosure and sending it to said bottom end of the first enclosure;

E) first gas heater means suitable for heating the gas flowing in a said second top pipe between the top end of said second enclosure and said first compression/expansion group, and preferably second gas heater means suitable for heating the gas inside said second enclosure; and

F) gas cooler means, preferably a heat exchanger, suitable for cooling the gas flowing in said first bottom pipe between the bottom end of the first enclosure and said second compression/expansion group.

2. An energy storage and return installation according to claim 1, wherein said first and second pistons are mechanically coupled to a common crank shaft suitable for being driven in rotation by said electric motor and suitable for driving said electricity generator, the movements of said first and second pistons preferably being set to be in phase opposition at 180°

C.

3. An energy storage and return installation according to claim 2, wherein each of the first and second cylinders includes at least two valves respectively enabling gas to be admitted to and exhausted from said first and second cylinders, the opening and closing of said valves being controlled as a function of the positions of the pistons in said cylinders or as a function of the values of gas pressure in said cylinders.

4. An electrical energy storage and return installation according to claim 1, wherein it is filled with an inert gas, preferably argon.

5. An electrical energy storage and return installation according to claim 1, wherein:

said first enclosure and first porous refractory material are capable of withstanding a temperature T1 of at least 300°

C., preferably of at least 300°

C. to 1000°

C., more preferably of 400°

C. to 600°

C.; and

said second enclosure and second porous refractory material are capable of withstanding a temperature T2 of at least 100°

C., preferably of at least 100°

C. to 500°

C., more preferably of 200°

C. to 400°

C.

6. An electrical energy storage and return installation according to claim 1, wherein said first cylinder is of greater volume than said second cylinder.

7. An electrical energy storage and return installation according to claim 1, wherein said first cylinder is dimensioned to compress and to expand respectively, and to heat and to cool respectively a gas between said temperatures T1 and T2, while said second cylinder is dimensioned to compress and to expand respectively and to heat and to cool respectively a gas between a temperature T3 lying in the range −

50°

C. to −

20°

C. and ambient temperature T0.

8. An installation for storing and returning energy according to claim 1, wherein said first and second porous refractory materials present porosities lying in the range 20% to 60%.

9. An installation for storing and returning energy according to claim 8, wherein said first and second porous refractory materials are constituted by porous bricks assembled one against another, preferably having cylindrical perforations passing therethrough that are disposed parallel in a common longitudinal direction that is the longitudinal direction of the enclosure in which they are assembled, said perforations more preferably being of a diameter in the range 5 mm to 20 mm.

10. An installation for storing and returning energy according to claim 1, wherein said first and second porous refractory materials are constituted by fire clay having high contents of compounds selected from magnesia, alumina, and lime.

11. An installation for storing and returning energy according to claim 1, wherein said first porous refractory material is constituted by second-firing fire clay or chamotte.

12. An installation for storing and returning energy according to claim 1, wherein said second porous refractory material is constituted by first-firing fire clay.

13. An installation for storing and returning energy according to claim 1, wherein said first and second enclosures have respective volumes of not less than 500 m³, and preferably lying in the range 1000 m³ to 5000 m³.

14. An electrical energy storage and return installation according to claim 1, wherein each of said first and second enclosures is constituted by a plurality of vertical steel columns having their top ends and bottom ends respectively connected to a common said top pipe and a common said bottom pipe via a top manifold and a bottom manifold respectively.

15. A method of storing electrical energy in the form of heat energy, in which an installation according to claim 1 is used, wherein, after an initial step of preheating the gas of said second enclosure that is heated to a temperature T₂, said installation being filled with a permanent gas that is initially at ambient temperature T₀, the following successive steps are performed:

1) the gas leaving the top end of the second enclosure at a temperature T₂ is heated to a temperature T₁ higher than a temperature T₂ by being compressed in a said first compression/expansion group operating in compressor mode before being delivered to the top end of said first enclosure, in which a pressure P1 is established higher than the pressure P2 of the second enclosure, said first compression group being driven by said electric motor powered by the electrical energy that is to be stored; and

2) the gas passes right through said first enclosure between said top end and its said bottom end, and it leaves said bottom end of the first enclosure at an ambient temperature T0 or a temperature T′

1 greater than T0 but less than T2; and

3) the gas is then cooled, where appropriate, to an ambient temperature T0 by said gas cooler means, preferably of the heat exchanger type, located downstream from the outlet from the bottom end of the first enclosure; and

4) the gas is then expanded through a said second compression/expansion group operating in expansion mode, to said pressure P2 of the second enclosure that is lower than the pressure P1, the gas thus being cooled to a temperature T3 lower than T0 prior to entering into said second enclosure via its bottom end; and

5) the gas is caused to flow through said second enclosure between said bottom and top ends of the second enclosure, thereby having the effect of increasing the volume of the refractory material in the bottom portion of said second enclosure that is cooled to the temperature T3, and of decreasing the volume of its top portion that is at the temperature T2 or T2 lower than T2 but greater than T0 and T′

1, and if necessary, where appropriate, the gas leaving the end of the second enclosure at the temperature T2 is heated to the temperature T′

2 with the help of second gas heater means; and

6) above steps

     1) to

     5) are repeated until the top portion of the first enclosure heated to the temperature T1 occupies at least 80% of the volume of said first enclosure, and the bottom portion of the second enclosure cools to a temperature T3 occupying at least 80% of the volume of the second enclosure.

16. A method according to claim 15, wherein in step 6), storage is interrupted so that the bottom portion of the first enclosure at said temperature T′

1 represents at least 10% of the volume of the first enclosure, preferably 10% to 20% of the volume of the first enclosure, and/or the top portion of the second enclosure at the temperature (T2) represents less than 20%, preferably 10% to 20% of the volume of said second enclosure.

17. A method according to claim 15, wherein said temperatures T1 and T2 are such that T1/T2=1.2 to 2 and T1/T0 is greater than 1.3, preferably greater than 1.5, and more preferably less than 2.5, and P1/P2 lies in the range 2 to 4.

18. A method according to claim 15, wherein T1 is 300°

C. to 1000°

C., preferably 400°

C. to 600°

C., and T2 is 100°

C. to 500°

C., preferably 200°

C. to 400°

C.

19. A method according to claim 17, wherein the pressure P1 lies in the range 20 to 300 bars absolute (2 MPa to 30 MPa), and the pressure P2 lies in the range 10 to 100 bars absolute (1 MPa to 10 PMa).

20. A method according to claim 17, wherein T0 lies in the range 10°

C. to 40°

C. and T3 lies in the range −

50°

C. to −

20°

C., T1′

lying in the range 20°

C. to 100°

C., where appropriate.

21. A method according to claim 17, wherein the quantity of electrical energy stored lies in the range 20 MWh to 1000 MWh.

22. A method of returning electrical energy (E_R) from heat energy stored by a method according to claim 15, wherein, after an initial starting stage in which said first and second compression groups are driven by the said electric motor, during which initial stage said first and second groups are caused to operate respectively in expansion mode and in compression mode in such a manner as to establish a pressure gradient between the pressure P1 in the first enclosure and a pressure P′

2 less P′

1 in the second enclosure, P1 preferably being greater than P1 and P2 preferably being less than P2, the following successive steps are performed;

1) the gas leaving via the top end of the first enclosure at said temperature T1 is expanded and cooled to the temperature T2 through said first expansion/compression group operating in expansion mode and driving said electricity generator enabling returned electrical energy to be delivered; and

2) the gas passes through said second enclosure from its top end to its bottom end, a top portion of the second enclosure being heated to said temperature T2, a bottom portion of the second enclosure remaining at said temperature T3; and

3) the gas leaving the bottom end of said second enclosure at the temperature T3 is then compressed by passing through said second compression/expansion group operating in compression mode that is driven by the energy released by said first compression/expansion group operating in expansion mode so as to be heated to a temperature T4 greater than an ambient temperature T0 and where appropriate greater than T′

1, but less than T2, at the outlet from said second compression/expansion group; and

4) preferably, the gas is then cooled to the ambient temperature T0 or T′

1 by said cooler means prior to being introduced into said first enclosure by its bottom end to enter the bottom portion of said first enclosure which is at said temperature T′

1; and

5) the gas is caused to flow through said first enclosure, thereby having the effect of increasing the volume of refractory material in the bottom portion that is at said temperature T′

1 and of decreasing the volume of refractory material in the top portion that is at said hot temperature T1; and

6) above steps

     1) to

     5) are repeated until the bottom portion of the first enclosure at said temperature (T1) represents at least 80% of the volume of the first enclosure, and the top portion of said second enclosure at said temperature (T2) represents at least 80% of the volume of said second enclosure.

23. A method according to claim 22, wherein in step 6), the energy return method is interrupted so as to maintain a top portion of the first enclosure at a said temperature T1, said top portion representing less than 20%, preferably 10% to 20% of the volume of said first enclosure, and/or a bottom portion of the second enclosure at said cold temperature T3 represents less than 20%, preferably 10% to 20%, of the volume of the second enclosure.

24. A method according to claim 22, wherein the efficiency E_R/E₁ with which electrical energy is returned by said electricity generator is greater than 60%, and preferably lies in the range 70% to 80%.

25. A method according to claim 22 wherein the ratio P′

1/P′

2 lies in the range 2.2 to 5.

26. A method according to claim 22, wherein T4 lies in the range 30°

C. to 100°

C.

27. A method according to claim 22, wherein the pressure P′

1 lies in the range 60 to 400 bars absolute (6 MPa to 40 MPa) and P′

2 lies in the range 15 to 90 bars absolute (1.5 MPa to 9 MPa).