LNG regasification

Abstract

An apparatus and method for generating electrical energy and for vaporising a cryogenically liquefied gas, the device having a conduit for the cryogenically liquefied gas, a pump located in the conduit, a heat engine, and a waste-heat recovery system downstream of the heat engine, wherein a branch conduit branches off from the conduit and the branch conduit leads into the heat engine, and wherein the apparatus also has a fluid circuit with the following components arranged successively in the flow direction of the fluid: a first heat exchanger which is also connected in the flow direction of the cryogenically liquefied gas past the pump into the conduit; a compressor; a second heat exchanger; parallel to one another, a third heat exchanger with a first side, and the waste-heat recovery system; a depressurising machine having a coupled generator; and the third heat exchanger with a second side.

Claims

1. An apparatus for generating electric energy and for vaporizing a low-temperature liquefied gas, comprising: a conduit for the low-temperature liquefied gas, a pump arranged in the conduit, a heat engine, a waste heat utilization system located downstream of the heat engine, a branch conduit which branches off from the conduit, wherein the branch conduit opens into the heat engine, and a fluid circuit in which the following components are arranged in succession in a flow direction of the fluid: a first heat exchanger which is installed in the conduit further in the flow direction of the low-temperature liquefied gas downstream of the pump, a compressor, a second heat exchanger, in parallel, a first side of a third heat exchanger and the waste heat utilization system, an expansion engine with coupled generator, and a second side of the third heat exchanger.

2. The apparatus as claimed in claim 1, wherein a first side of a fourth heat exchanger is arranged in parallel to the first side of the third heat exchanger and upstream in the flow direction of the fluid of the waste heat utilization system in the fluid circuit, and wherein a second side of the fourth heat exchanger is arranged downstream in the flow direction of the fluid of the second side of the third heat exchanger in the fluid circuit.

3. The apparatus as claimed in claim 2, wherein a fifth heat exchanger is arranged in the branch conduit and in the fluid circuit upstream of the second side of the third heat exchanger.

4. The apparatus as claimed in claim 3, wherein a sixth heat exchanger is arranged in the conduit upstream of a branching-off point of the branch conduit.

5. The apparatus as claimed in claim 1, wherein the low-temperature liquefied gas is natural gas.

6. The apparatus as claimed in claim 1, wherein the fluid circuit is a nitrogen circuit.

7. A process for generating electric energy and for vaporizing a low-temperature liquefied gas, the process comprising: compressing, heating, and vaporizing a low-temperature liquefied gas by a fluid stream in a first heat exchanger, wherein the fluid stream is circulating in a fluid circuit, with it being compressed downstream of the first heat exchanger, taking up heat in a second heat exchanger, being divided into a first substream and a second substream, with the first substream being heated at least in a waste heat utilization system by exhaust gases of a heat engine and the second substream being heated in a third heat exchanger and the first substream and the second substream being combined again into a combined fluid, the combined fluid being depressurized and subsequently heating the second substream in the third heat exchanger before it heats the low-temperature liquefied gas in the first heat exchanger.

8. The process as claimed in claim 7, wherein the first substream, before it is heated in the waste heat utilization system, is heated by the fluid in a fourth heat exchanger after the fluid has heated the second substream in the third heat exchanger.

9. The process as claimed in claim 7, wherein the formerly low-temperature liquefied gas is fed at least partly to a gas grid and partly to the heat engine.

10. The process as claimed in claim 9, wherein the formerly low-temperature liquefied gas fed to the heat engine is preheated by way of the fluid in a fifth heat exchanger for a combustion before it heats the second substream in the third heat exchanger.

11. The process as claimed in claim 7, wherein nitrogen is used as fluid in the fluid circuit.

12. The process as claimed in claim 11, wherein the fluid circuit is operated under supercritical conditions.

13. The process as claimed in claim 7, wherein liquefied natural gas is used as low-temperature liquefied gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be illustrated in more detail by way of example with the aid of the drawing. In the drawing, schematically and not true-to-scale:

(2) FIG. 1 shows an apparatus for generating electric energy and for vaporizing liquefied natural gas according to the invention.

DETAILED DESCRIPTION OF INVENTION

(3) FIG. 1 schematically shows, by way of example, an apparatus 1 according to the invention. It comprises a conduit 2 for the low-temperature liquefied gas, for example natural gas, and a pump 3 arranged in the conduit 2. Furthermore, the apparatus 1 in FIG. 1 comprises a gas turbine as a heat engine 4 and also a waste heat utilization system 5 similar to a waste heat steam generator in gas and steam turbine plants located downstream of the heat engine 4. However, the invention does not provide a water-steam circuit.

(4) The fluid circuit 6 could be, for example, a nitrogen circuit and in the working example of FIG. 1 comprises the following components in succession in the flow direction of the fluid: —a first heat exchanger 7 which is installed in the conduit 2 further in the flow direction of the low-temperature liquefied gas downstream of the pump 3; in the first heat exchanger 7, heat is, for example, transferred by nitrogen to the liquefied natural gas, resulting in the liquefied natural gas warming up and vaporizing, —a compressor 8 by means of which the fluid/the nitrogen can be brought to the supercritical pressure range for optimum heat exchange, —a second heat exchanger 9 in which ambient heat (for example from a gas turbine intake air cooling facility, seawater, ambient air, warmed-up cooling water) is utilized for heating the fluid, —in parallel, a first side 11 of a third heat exchanger 10 in a second substream 23 and a first side 16 of a fourth heat exchanger 15 and the waste heat utilization system 5 in a first substream 22 of the fluid, —a turbine as an expansion engine 13 with coupled generator 14, —a fifth heat exchanger 19 for preheating of fuel, —a second side 12 of the third heat exchanger 10 and—a second side 17 of the fourth heat exchanger 15.

(5) In the working example of FIG. 1, part of the depressurized natural gas is fed to a gas grid 24 and another part is fed to the gas turbine (heat engine 4). For this purpose, a branch conduit 18 branches off from the conduit 2 at the branching-off point 21. The branch conduit 18 opens into the gas turbine (heat engine 4). To preheat fuel, the fifth heat exchanger 19 is, as indicated above, installed in the branch conduit 18 and in the fluid circuit 6 (=nitrogen circuit).

(6) In the working example of FIG. 1, a sixth heat exchanger 20 is also arranged in the conduit 2 upstream of a branching-off point 21 of the branch conduit 18.

(7) The turbine 13 in which nitrogen is expanded in the working example of FIG. 1 has leakages. These can be at least partly extracted 25 and then recirculated into the fluid circuit 6. In general, an introduction 26 of nitrogen into the fluid circuit 6 is provided.