Method for power generation during the regasification of a fluid by supercritical expansion

Abstract

An apparatus and method for power generation during regasification, having a tank for a cryogenic fluid, a first pump connected to the tank via a first line, a first heat exchanger connected to the first pump via a second line, and a second heat exchanger connected downstream of the first heat exchanger, and a first turbine connected immediately downstream of the second heat exchanger, wherein a third line branches off from the first turbine and opens into the first heat exchanger, and a fourth line branches off from this first heat exchanger and opens into the second line, wherein a second pump is connected into the fourth line.

Claims

1. A device for power generation during regasification, comprising: a tank for a cryogenic fluid, a first pump which is connected to the tank via a first line, a first heat exchanger which is connected to the first pump via a second line and a second heat exchanger which is arranged downstream of the first heat exchanger, and a first turbine which is arranged directly downstream of the second heat exchanger, wherein a third line branches off from the first turbine and opens in the first heat exchanger and a fourth line branches off from this first heat exchanger and opens in the second line between the first pump and second heat exchanger upstream of the first heat exchanger, wherein a second pump is connected in the fourth line, wherein a third heat exchanger is connected in the second line and in the fourth line upstream of the second pump.

2. The device as claimed in claim 1, wherein a fifth line branches off from the first turbine and opens in a pipeline.

3. The device as claimed in claim 2, wherein a fourth heat exchanger is connected in the fifth line.

4. The device as claimed in claim 3, wherein a second turbine is connected in the fifth line and the fourth heat exchanger is arranged downstream of the second turbine.

5. The device as claimed in claim 4, wherein a fifth heat exchanger is arranged upstream of the second turbine in the fifth line.

6. The device as claimed in claim 1, wherein the first heat exchanger, third heat exchanger and introduction location of the fourth line into the second line are arranged in an integrated heat exchanger.

7. The device as claimed in claim 1, wherein the tank contains liquid natural gas.

8. A method for power generation, comprising: bringing a fluid to a first pressure and consequently producing a high-pressure flow, combining the high-pressure flow with a second fluid flow which is greater than the high-pressure flow, into a total fluid flow, guiding the total fluid flow to a first heat exchanger, and heating the total fluid flow by the second fluid flow, resulting in a heated total fluid flow, subsequently further heating the heated total fluid flow in a second heat exchanger by introducing ambient heat and/or waste heat from other processes, resulting in a further heated total fluid flow, expanding the further heated total fluid flow in a first turbine to a lower but supercritical pressure, resulting in an expanded total fluid flow, dividing the expanded total fluid flow, which is discharged from the first turbine, into the second fluid flow and into a smaller third fluid flow, wherein the second fluid flow, after it has discharged heat to the total fluid flow, is brought to a pressure level of the high-pressure flow, and combined with the high-pressure flow upstream of the first heat exchanger, wherein the second fluid flow, before it is brought to the pressure level of the high-pressure flow, is further cooled by a third heat exchanger, wherein the high-pressure flow is heated.

9. The method as claimed in claim 8, wherein the fluid is removed from a tank.

10. The method as claimed in claim 9, wherein by means of a first pump the fluid removed from the tank is brought to a pressure of over 150 bara.

11. The method as claimed in claim 8, wherein the ambient heat is removed from air or seawater.

12. The method as claimed in claim 8, wherein the further heating is carried out to at least 5° C. below ambient temperature.

13. The method as claimed in claim 8, wherein the lower, but supercritical pressure is over 70 bara.

14. The method as claimed in claim 8, wherein the third fluid flow is introduced into a pipeline.

15. The method as claimed in claim 8, wherein multi-stage expansion and intermediate heating are carried out in the first turbine.

16. The method as claimed in claim 9, wherein the fluid removed from the tank is liquid air, liquid natural gas, liquid nitrogen, liquid oxygen or liquid argon.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail by way of example with reference to the drawings. In the drawings which are schematic and not to scale:

(2) FIG. 1 shows a basic circuit for the process for power generation according to the invention,

(3) FIG. 2 shows a circuit for lower pipeline pressure,

(4) FIG. 3 shows a circuit for cost optimization by omitting the recuperator,

(5) FIG. 4 shows an embodiment with an integrated heat exchanger and

(6) FIG. 5 is a flow chart for the method according to the invention.

DETAILED DESCRIPTION OF INVENTION

(7) FIG. 1 shows schematically and by way of example the basic circuit for the device 1 for power generation during regasification according to the invention. The device 1 comprises a tank 2 for a cryogenic fluid, advantageously liquid natural gas (LNG), but liquid air, liquid nitrogen, liquid oxygen or liquid argon are also possible. A first pump 4 is connected to the tank 2 by means of a first line 3. A second line 5 connects the first pump 4 to a first heat exchanger 6, downstream of which a second heat exchanger 7 is arranged, downstream of which a first turbine 8 is in turn arranged. According to the invention, a third line 9 branches off from the first turbine 8 and opens in the first heat exchanger 6, from which a fourth line 10 branches off in turn and opens in the second line 5.

(8) A second pump 11 is arranged in this fourth line 10 and, upstream of the second pump 11, a third heat exchanger 12. The third heat exchanger 12 is further connected in the second line 5.

(9) In the embodiment of FIG. 1, a fifth line 13 branches off from the first turbine 8 and opens in a pipeline 14. Furthermore, a fourth heat exchanger 15 is connected in the fifth line 13.

(10) The circuit of FIG. 2 is optimized for a lower pipeline pressure. In this instance, a second turbine 16 is connected in the fifth line 13, wherein the fourth heat exchanger 15 is arranged downstream of the second turbine 16. Furthermore, a fifth heat exchanger 17 is arranged upstream of the second turbine 16 in the fifth line 13.

(11) The embodiment of FIG. 3 serves to optimize costs. The third heat exchanger 12 in the line 10 is omitted. The fluid reaches the second pump 11 directly from the heat exchanger 6 before it is returned to the second line 5.

(12) FIG. 4 finally shows an embodiment with an integrated heat exchanger 18, that is to say, a first heat exchanger 6, third heat exchanger 12 and introduction location 19 of the fourth line 10 into the second line 5 are integrated in one component.

(13) FIG. 5 shows a diagram relating to the method for producing power. In a first step 101, the fluid—liquid air, liquid natural gas, liquid nitrogen, liquid oxygen or liquid argon—is removed from a tank 2.

(14) In a second step 102, the fluid removed from the tank 2 is brought to a first pressure and consequently a high-pressure flow is produced. This first pressure is above 150 bara.

(15) This high-pressure flow is combined in a third step 103 with a second fluid flow, which is greater than the high-pressure flow.

(16) In a fourth step 104, the resulting total fluid flow is guided to a first heat exchanger 6, in which the total fluid flow is heated by the second fluid flow.

(17) In a fifth step 105, the heated total fluid flow is further heated in a second heat exchanger 7 by introducing ambient heat and/or waste heat from other processes. In the case of ambient heat, this can be carried out via air or, for example, sea water and the temperature which can be reached should come as close as possible to the ambient temperature. The temperature which can be reached is dependent on the temperature differences of the heat exchangers used. The target temperature should be as high as possible, but no more than 5° C. below the ambient temperature.

(18) In a sixth step 106, the total fluid flow which is further heated is expanded in a first turbine 8 to a lower, but supercritical pressure. This pressure is typically above 70 bara.

(19) The steps five 105 and six 106 can be repeated depending on the embodiment so that a multi-stage expansion and intermediate heating are carried out in the first turbine 8.

(20) In a seventh step 107, the total fluid flow discharged from the first turbine 8 is divided into the second fluid flow and into a smaller third fluid flow.

(21) In an eighth step 108, the second fluid flow discharges heat to the total fluid flow.

(22) In a ninth step 109, the second fluid flow is brought to the pressure level of the high-pressure flow before it is combined with it (step 3).

(23) In a tenth step 110, the third fluid flow in introduced into a pipeline 14.