Gas discharge system

Abstract

The invention relates to a gas expansion system (100, 200) for expansion and quantity control of gas for use between a first, upstream gas source (Q), such as a gas tank, a medium-pressure gas network or a high-pressure gas network or a cavern storage facility and at least a second, downstream gas sink (S1), such as a consumer, a low-pressure gas network or a gas supply line, comprising at least a first vortex tube (10) which is in flow connection with the first, upstream gas source (Q) via an inlet, wherein the gas from the gas source (Q) flows into the at least one first vortex tube (10) in a tangential inlet (11) and flows out of two outlets in the form of a first outlet (12) for a first cold fraction (KF) of the gas and in the form of a second outlet (13) for a second hot fraction (WF) of the gas.According to the invention, a first stage (I) comprises at least one gas expansion device, such as a throttle, a vortex tube (10) or an expansion turbine (D0) and at least one first heat exchanger (WT0, WT1), wherein the gas to be expanded flows via a gas line into both the at least one gas expansion device and the at least one heat exchanger (WT0, WT1), wherein the expanded gas flowing out of the at least one gas expansion device also flows into the at least one heat exchanger (WT0, WT1), and wherein the gas to be expanded cools down in the at least one heat exchanger (WT0, WT1) and the gas cooled by expansion heats up in the at least one heat exchanger (WT0, WT1), wherein the expanded and heated gas flows via a first gas line to the sink (S1), and wherein the gas to be expanded and cooled flows to a further application.

Description

[0001] The invention relates to a gas expansion system for expanding and controlling the quantity of gas for use between a first, upstream gas source, such as a gas tank, a medium-pressure gas network or a high-pressure gas network or a cavern storage facility, and a second, downstream gas sink, such as a consumer, a low-pressure gas network or a gas supply line, comprising at least one first vortex tube which is in flow connection with the first, upstream gas source, wherein the gas flows from the gas source into the at least one first vortex tube into a tangential inlet and flows out of two outlets in the form of a first outlet for a first cold fraction of the gas and in the form of a second outlet for a second warm fraction of the gas.

[0002] When distributing gases, for example from a medium- or high-pressure gas network into a distribution network with lower pressure, or when taking gases from a pressure reservoir such as an aquifer, a cavern storage facility or a gas tank into a pipeline network, it is necessary to release the pressurised gas in order to adjust the pressure for pipeline transport. In contrast to ideal gases, real gases exhibit the well-known Joule-Thomson effect when passing through a throttle. The Joule-Thomson effect is characterised by an observable change in the temperature of a gas when the pressure is reduced isenthalpically. The direction (cooling or even heating) and strength of the effect are determined by the strength of the attractive and repulsive forces (van der Waals forces) between the gas molecules. Under normal conditions, most common gases and gas mixtures, e.g.Also, air, a temperature reduction during expansion, i.e., a pressure reduction during flow through a throttle. In pipeline networks that carry high volume flows, such as municipal gas supply lines, regional gas supply lines, or longer gas pipelines, it is necessary that both the pressure in the supply line and the temperature of the flowing gas remain within certain limits. The units present in the supply lines, such as pressure regulators, valves, heat exchangers, and compressors, often have narrow intervals in which the state variables of the transported gas must be present in order to function safely and in a predetermined manner.

[0003] Wet natural gas, i.e. methane (CH 4 ) with admixtures of nitrogen (N 2 ), possibly acidic gases such as hydrogen sulfide (H 2 S) and carbon dioxide (CO 2 ), as well as moisture in the form of water vapor (H 2 O) and small amounts of ethane (C 2 H 6 , 1% to 15%), propane (C 3 H 8 , 1% to 10%), butane (C 4 H 10 ), ethene (C 2 H 4 ) and pentanes (C 5 H 12 ), tends to freeze when cooled sharply due to the Joule-Thomson effect. When wet natural gas freezes, methane hydrate (CH 4 • 5.75 H 2 O) in particular precipitates out. Methane hydrate is a clathrate compound in which water and methane form a cage compound. Methane hydrate externally resembles snow or hoarfrost and, once formed in cold conditions, can survive at temperatures as low as 20°C. Although methane hydrate is thermodynamically unstable at room temperature, i.e., around 20°C, the clathrate compound tends to remain in a superheated state before decomposing back into its gaseous components.If methane hydrate, ice, or other gas hydrates form, the hydrate can clog the gas line, restrict the gas line's cross-section, clog or immobilize valves or pressure regulators, block the mechanical control path of pressure regulator diaphragms, and prevent flow meters from accessing the gas flow. The formation of ice, methane hydrate, or other gas hydrates in a gas supply line can quickly lead to a dangerous pipeline failure, which is hazardous to life and limb.

[0004] To prevent gases from freezing during expansion, it is known to significantly heat the gas before the throttle, with the gas cooling again as it passes through the throttle. It is also known to pass the throttled gas through ice-free throttles and then reheat the cooled gas. Heating is achieved using electric heaters or gas heating, as gas is readily available as a fuel in the vicinity of a gas supply line.

[0005] With growing awareness of the potential for energy savings, but also with growing awareness of the harmful effects of large amounts of carbon dioxide in the atmosphere on the global climate caused by the combustion of heating gas, there is a need to carry out gas expansion in a climate-neutral manner, particularly in municipal or regional supply lines, but also in pipelines. Another need is to carry out gas expansion in the absence of ignition sources, such as electric or gas heaters, in order to protect municipal or regional supply lines from accidents.

[0006] The East German patent specification DD 108 146 discloses a device for liquefaction or refrigeration. According to the principle of DD 108 146, gas from a high-pressure source is passed through a vortex tube. The warm fraction flowing from the vortex tube is either fed to a further process or returned to the high-pressure side via a heat exchanger and recompressor. The cold gas stream, on the other hand, is fed for further liquefaction. Although this process is suitable for liquefying gas, it is quite energy-inefficient.

[0007] According to the teaching in German patent DE 101 51 321 B4, disproportionation, which refers to the division of a gas stream through a vortex tube into a warmer and a colder fraction, is used to protect the gas expansion element itself from icing. Patent DE 101 51 321 B4 explicitly teaches that the warm fraction should shield the cold fraction. According to the teaching in patent DE 101 51 321 B4, the cold fraction and the warm fraction are recombined after expansion, and if necessary, the heat is first transferred via a heat exchanger before the gas fractions are recombined.

[0008] The subsequently published patent application 10 2019 120 358.9 teaches the use of a vortex tube as part of a heat pump in a gas expansion system. The gas, disproportionated into two different fractions by a vortex tube, is fed directly into the gas sink as the warm fraction. Meanwhile, the significantly cooled gas from the vortex tube is passed through an atmospheric heat exchanger, which heats the significantly cooled gas to atmospheric temperatures. The combined warm fraction with the atmospherically heated catalyst fraction contains enough heat to be transported into a medium-pressure or low-pressure gas network within a desired temperature range of more than 15°C. The use of the atmospheric heat exchanger is limited to regions where seasonal temperatures do not fluctuate too greatly.In winters with very low temperatures, a gas expansion system designed in this way may no longer be able to operate reliably without additional heating.

[0009] The subsequently published patent application 10 2019 121 925.6 teaches a cascade of vortex tubes connected in series on the cold flow side for gas expansion. As the cold fractions travel through the tubes, the gas to be expanded cools significantly until it finally liquefies. The use of the vortex tube cascade eliminates the need for a heater to heat the gas, which cools during expansion. The heat is extracted from a thermal disproportion within the gas to be expanded. During this thermal disproportion, part of the gas heats up, while another part cools down. The amount of liquefied gas produced is comparatively small. A significant portion of a cold medium-pressure gas is also produced.

[0010] The international patent application WO2019 / 145230 A1 discloses a method for producing liquefied gas in a gas storage facility by generating cold through expanding gas.

[0011] Chinese patent CN 108 759 302 B discloses a method for producing liquefied gas in a gas storage facility by generating cold by expanding gas in a cascade of series-connected expansion turbines.

[0012] US patent application US 2020-103146 A1 discloses a process for producing liquefied gas in a gas storage facility using a non-freezing vortex tube. In a first heat exchanger stage, the pressurized gas is pre-cooled by the cold fraction of the vortex tube.

[0013] US Patent No. 3,672,179 A discloses a process for producing liquefied petroleum gas and a corresponding apparatus comprising serially connected Ranque tubes (vortex tubes). Boiling gas above the liquefied petroleum gas is used to cool the Ranque tubes.

[0014] US patent application US 2006-0075777 A1 discloses a process for producing liquefied petroleum gas and a corresponding apparatus for producing liquefied petroleum gas. Cool gas is used to freeze water and carbon dioxide during the process of converting the pressurized gas into liquefied petroleum gas.

[0015] The object of the invention is to provide an economical plant for the expansion and quantity control of gas, and in a preferred embodiment for the production of liquefied gas and hydrogen from hydrogen-enriched natural gas.

[0016] The object of the invention is achieved by a gas expansion system having the features of claim 1. Further advantageous embodiments are specified in the subclaims to claim 1.

[0017] According to the concept of the invention, as in the previously described systems, gas from a gas source, such as a cavern storage facility, in which gas is present at between 100 bar and 300 bar, is expanded. The cooled and expanded gas is then heated with another portion of the pressurized gas. This cools the pressurized gas. Depending on the number of different available gas discharge sources with different pressure levels, the gas cooling described above can occur several times in succession until the pressurized gas condenses into liquefied natural gas (LNG).

[0018] In a first embodiment of the invention, the pressurized gas is expanded through a vortex tube as a throttle. This creates a warm fraction and a cold fraction. The heat for heating is not extracted from the atmosphere, as is the case with heating the cold fraction in an atmospheric heat exchanger. The heat is also not conducted through a vortex tube cascade, in which the warm fractions are created at ever-decreasing pressure.

[0019] The concept of the invention is to extract the heat required to heat the expanded gas from the gas on the high-pressure side. Instead of an atmospheric heat exchanger, the efficiency of which depends in part on the respective seasonal temperatures, the high-pressure gas is used as the heat source to heat the cold fraction from the vortex tube. The use of the high-pressure gas has a particular advantage. Because the gas is under high pressure, its heat capacity, relative to the volume flowing through a heat exchanger, is greater than that of air at atmospheric pressure. Heating the expanded gas in a heat exchanger heated by the high-pressure gas is much more efficient.By extracting heat from the high-pressure gas to heat the expanded gas, the present gas expansion system is completely independent of atmospheric conditions and it is possible to dispense with heating the expanded gas by heating with an external energy source.

[0020] The cooled, high-pressure gas itself is now used for other purposes. It is no longer suitable for expansion and introduction into a medium-pressure or low-pressure network unless it is first heated. But that is not the current objective.

[0021] According to the concept of the invention, it is further provided that the cooled gas, which is still under high pressure, is cooled even further. For this purpose, it is provided that a second outlet of the first heat exchanger for the gas from the gas source that has flowed through the first heat exchanger opens into two lines, wherein a) a first line is in flow connection with a first throttle, and b) a second line is in flow connection with a second heat exchanger, wherein the first throttle is also in flow connection with the second heat exchanger downstream, whereby the gas that has flowed through the first throttle and has cooled in the process absorbs heat from the gas that has passed through the first line as medium-pressure gas, and wherein the path of the medium-pressure gas is connected via a first outlet to another gas sink located downstream of the gas.The concept of the invention involves splitting the cooled, high-pressure gas into two gas streams via a pipe divider. A first gas stream remains at its original pressure, having suffered a negligible, minimal pressure loss through the first heat exchanger. A second gas stream is passed through a throttle. The gas in the second stream is pre-cooled and cools even more as it passes through the throttle. The thus cooled gas is then reheated by the first partial stream of gas, still under high pressure, in a second heat exchanger, and the heated gas, expanded by the first throttle, is then passed into a low-pressure network.

[0022] The gas, which has now been cooled twice and is still under high pressure, can now be passed through a throttle, where it cools down again and produces liquefied gas, i.e. liquid natural gas.

[0023] It is therefore provided that a second outlet of the second heat exchanger for the gas which has previously passed through the second line to the second heat exchanger is in flow connection with a second throttle, wherein the downstream outlet of the second throttle is in flow connection with a first separator which separates liquid gas from boiling gas.

[0024] The liquefied natural gas is collected in the separator. The boil-off gas rising from the separator can be compressed back to the low-pressure level using a compressor and fed into the low-pressure network. According to this embodiment, the boil-off gas can be fed via a boil-off line to a compressor, which compresses the boil-off gas to the pressure of the second, downstream gas sink and feeds it into it.

[0025] More recently, there are plans to add gaseous hydrogen (H2) to natural gas. What was once considered unthinkable - adding higher-quality hydrogen as a chemical base to a less noble fuel that produces CO2 and is mixed with nitrogen and other natural gases - has now become conceivable from a completely different perspective. Firstly, hydrogen serves as an energy carrier for a number of renewable energy sources. One of the most important renewable energy sources is wind power, whose electrical energy is difficult to store. Therefore, otherwise unused electrical energy is converted into hydrogen through water electrolysis. The resulting hydrogen is added to natural gas. This increases the calorific value of the natural gas. Furthermore, the addition of hydrogen leads to the substitution of fossil fuels with renewable energy.In a gas expansion plant, it may be economical to separate the gas transported with the natural gas into its components. Gas separation is typically performed using a Linde process. However, the energy consumption for the compression and expansion cycle would be so high that separating the mixed gas into natural gas and hydrogen would not be economically viable. The invention provides for the cooled gas to be cooled to such an extent that natural gas condenses quantitatively as LNG. The admixed hydrogen remains in the gas space and can be discharged in a separator.To achieve quantitative condensation of natural gas, the boiling gas is further fed via a second boiling gas line to a third heat exchanger through which liquid nitrogen flows. The liquid nitrogen liquefies the boiling gas and itself passes into the gas space as gaseous nitrogen. Liquid nitrogen is a byproduct of the production of liquid oxygen and the production of pure argon from air liquefaction. It is economical to use the available liquid nitrogen to condense the natural gas instead of recompressing the boiling gas and feeding it into the low-pressure gas network.

[0026] For this purpose, it is provided that the liquefied boiling gas is fed via a third boiling gas line to a second separator, which separates liquefied gas from non-liquefied gas components, such as hydrogen and / or noble gases. It can further be provided that the liquid gas from the first separator is combined with the liquid gas from the second separator via a liquid gas line that connects the separators on the liquid side. Finally, it can also be provided that the non-liquefied gas components (H 2 , He, Ar) are fed into the gas tank (GT) via a low-boiling component line (LSL) between the second separator (SP2) and a gas tank (GT). The gas can then be fed from the gas tank for further use.

[0027] The invention is explained in more detail with reference to the following figures. It shows: Fig. 1 an explanatory sketch of the vortex tube used according to Ranque-Hilsch, Fig. 2 a gas expansion system not according to the invention, Fig. 3 a gas expansion system according to the invention, Fig. 4 a gas expansion system not according to the invention.

[0028] In Figure 1is a sectional drawing through a Ranque-Hilsch vortex tube 10 with vortices W1 and W2 drawn in, with the outer vortex W1 carrying the warm fraction and the inner vortex W2 carrying the cold fraction. The exact functioning of a Ranque-Hilsch vortex tube has not yet been scientifically clarified, despite the discovery of this effect around 90 years ago. However, the Ranque-Hilsch effect is reproducible and can also be empirically optimized for different volume flows and average operating pressures. As far as the function of the vortex tube 10 is objectively understood, pressurized gas GH flows into the vortex tube 10 through a tangential inlet 11. There, the inflowing gas GH forms various vortices W1 and W2 in the vortex tube, with gas that is warmer than the gas flowing into inlet 11 exiting the tube end at outlet 13 as the warm fraction WF.Outlet 13 is located at the pipe end opposite the pipe end at which the tangential inlet 11 is located. Gas that is significantly colder than the gas flowing into inlet 11 exits as cold fraction KF at outlet 12, which is located at the pipe end at which the tangential inlet 11 is also located. The amount of heat of the combined warm fraction WF and cold fraction KF corresponds approximately to the amount of heat of the incoming gas GH less the volume work V • ΔP as a heat equivalent that the incoming pressurized gas GH performed when passing through the vortex tube 10.

[0029] In contrast to a simple throttle in the form of a pinhole or a steel frit in a tube, in which a temperature reduction is measurable due to the observable Joule-Thomson effect, a cold fraction KF with a temperature below the temperature that would be observable due to the Joule-Thomson effect and a warm fraction WF with a temperature that is higher than the temperature of the inflowing gas GH are formed in a Ranque-Hilsch tube. The present invention takes advantage of the fact that the Ranque-Hilsch vortex tube 10 produces a cold fraction KF that has a temperature below the temperature that would be achievable according to Joule-Thomson. The heat extracted in this way is added to the warm fraction, which is used within the scope of this invention to heat the gas in the discharge network.

[0030] In the legend to Figure 1Three different thermometers are shown under a shaded square, each of which can be assigned to a shade of the vortices W1 and W2. Black (left) means cold and corresponds to the temperature of the escaping cold fraction KF. A medium-dark shade (center) corresponds approximately to the temperature of the pressurized, incoming gas GH, and a lighter shade (right) corresponds approximately to the temperature of the escaping warm fraction WF.

[0031] In Figure 2A gas expansion system 100 without hydrogen separation is shown. The gas expansion system 100 is used for the expansion and quantity control of gas. It is used between a first, upstream gas source Q, such as a gas tank, a medium-pressure gas network or high-pressure gas network, or a cavern storage facility on the high-pressure side, represented in the figure by a manometer symbol with a pointer turned all the way to the right. On the other side, there is at least one second, downstream gas sink S1, such as a consumer, a medium-pressure gas network, or a gas supply line, represented by a manometer symbol with a pointer positioned approximately in the middle. Depending on the configuration of the system, a further gas sink S2 may also be present in the form of a medium-pressure gas network with lower pressure or a low-pressure gas network, represented by a manometer symbol with a pointer positioned on the left.In the gas expansion system 100, the high-pressure gas from the source Q flows through at least one first vortex tube 10, which is in flow connection with the first, upstream gas source Q via an inlet. The high-pressure gas from the source Q flows into a tangential inlet 11 in the at least one first vortex tube 10. The tangential inlet 11 is in . Figure 1 shown. The gas flows out of the vortex tube 10 through two outlets, a first outlet 12 for a first cold fraction KF of the gas and a second outlet 13 for a second warm fraction WF of the gas. The outlets 12 and 13 are also Figure 1 shown in more detail.

[0032] The cold fraction KF of the gas flowing from the first outlet 12 of the at least one vortex tube 10 is in flow communication with a first heat exchanger WT1. This heat exchanger WT1 itself is further in flow communication with the first gas source Q located upstream of the gas stream. The cold fraction KF of the at least one vortex tube 10 absorbs heat from the gas stream from the gas source Q as it flows through the first heat exchanger WT1. In the process, the original cold fraction KF is heated.

[0033] A first outlet WT1A1 of this first heat exchanger WT1 is in flow connection with the second outlet 13 for the second warm fraction WF of the at least one vortex tube 10. Through this connection, the cold fraction KF of the at least one vortex tube 10, heated in the first heat exchanger WT1, is combined with the second warm fraction WF of the at least one vortex tube 10. The combined gas fractions now have a temperature of significantly more than -15°C, which is suitable for use in a gas distribution network. Without the need for additional heat from outside, the expanded gas, which had cooled during expansion, was heated with the heat in additional high-pressure gas. In the process, the remaining portion of the high-pressure gas from the gas source Q cooled itself, making it available for other uses. Up to this point, stage I of the system according to the invention has been reached, with an autologous heat supply for the expanded gas.

[0034] The stage I plant is followed by a further stage II. In stage II, the highly pressurized and cooled gas is divided into two partial streams.

[0035] The following circuit is proposed for this purpose: a second outlet WT1A2 of the first heat exchanger WT1 for the gas from the gas source Q that has flowed through the first heat exchanger WT1 opens into two lines WT1L1 and WT1L2. The first line WT1L1 is in flow connection with a first throttle D1 or an expansion turbine. The second line WT1L2, on the other hand, is in flow connection with a second, following heat exchanger WT2. The first throttle D1 or an expansion turbine is also in flow connection with the second heat exchanger WT2 downstream, but with a different inlet. As the two partial flows flow through the second heat exchanger WT2 through different parts of the heat exchanger WT2, the gas that has flowed through the first throttle D1 or an expansion turbine and has cooled in the process absorbs heat from the gas that has passed through the second line WTL2.The heated gas continues its course as medium pressure gas MDG, which is connected via a first outlet WT2A1 to another gas sink S2 located downstream of the gas stream.

[0036] In contrast, the gas cooled in the heat exchanger and still under high pressure flows out of the heat exchanger (WT) and is available for further use. This is the second stage II of the gas expansion system according to the invention.

[0037] In a third stage III, the following is planned for the cold gas: A second outlet WT2A2 of the second heat exchanger WT2 for the gas that previously passed through the second line WT1L2 to the second heat exchanger WT2 is in flow connection with a further, second throttle D2 or an expansion turbine in stage III. The already quite cold and high-pressure gas from the source is heavily pre-cooled and reaches the inversion temperature of some of the associated gases in the natural gas. When the cold, high-pressure gas now flows through the second throttle D2 or the expansion turbine in stage III, the cooling of the natural gas that occurs when an associated gas is expanded does not compensate for this. The strong pre-cooling corresponds to Fränkl's variation of the Linde process.During the expansion that now takes place in throttle D2 or the expansion turbine, the gas cools even more, as represented by the three ice crystals symbolizing cold. In stage III, at least a partial liquefaction of the natural gas takes place, which is already usable as LNG.

[0038] In a fourth stage IV, the following is planned: The downstream outlet D2A of the second throttle D2 or the expansion turbine in stage III is in flow communication with a first separator SP1, which separates liquefied natural gas (LNG) from boil-off gas (SG). Since the LNG has not yet cooled significantly, a portion of the gas continuously escapes from the LNG. During the transition from the liquid state to the gas space, the evaporating gas absorbs latent heat from the liquefied gas. Through this continuous cooling, evaporation acts like a thermostat. If heat from outside enters the separator, a portion of the LNG evaporates, cooling the remaining liquefied gas. The boil-off gas (SG) is then compressed by a compressor V1 to the pressure level of the intermediate-pressure network, which was introduced above as gas sink S2. The compression of the boiling gas SG by the compressor V1 is an energy-consuming process.Because the process is energy-consuming and therefore costly, it is economical to subject the boil-off gas (SG) to further treatment. Figure 3 a gas expansion system 200 is shown, which, due to the circuitry according to the invention in stage IV, is separated from the gas expansion system in Figure 2The boiling gas SG is fed from the first separator SP1 to a third heat exchanger WT3. Liquid nitrogen (LN 2 ) flows through this heat exchanger WT3 and cools the boiling gas SG further. Liquid nitrogen (LN 2 ) is a comparatively inexpensive by-product in the production of liquid oxygen from Linde air liquefaction and in the production of argon, for example as an industrial protective gas, also from air liquefaction. The nitrogen cooling, which is economically in competition with the energy-consuming compression and marketing of compressed natural gas to CNG, completely condenses the natural gas.The only gases left in the boiling gas SG from the second separator SP2 are those that do not liquefy at the temperature of liquid nitrogen under normal pressure, such as hydrogen, when this has been added to natural gas in significant quantities as a source of renewable energy. The addition of hydrogen to natural gas is also undertaken because there is no longer a hydrogen network equivalent to the natural gas network. The addition allows the hydrogen to be distributed in the same way. In the gas expansion plant, the hydrogen can be separated from the natural gas again without any particular economic burden, if desired. The hydrogen is transported under low pressure via a low-boiler line LSL to a gas tank. The low pressure is in . Figure 3 represented by the manometer symbol with a pointer turned strongly to the left.

[0039] In Figure 4a gas expansion system 300 is shown, which is also not according to the invention and which, due to the connection in stage I, is distinguished from the gas expansion systems in Figure 2 and Figure 3 and which does not show hydrogen separation.

[0040] In this system, there is no vortex tube, but instead of the vortex tube, there is a throttle D0, which can also be an expansion turbine. The previously shown in the figures Figure 1 and Figure 2 The throttle D1 of stage II shown can be an expansion turbine.

[0041] In the first stage I shown here, there is at least one gas expansion device, such as a throttle D0, an expansion turbine or a vortex tube 10 and at least one first heat exchanger WT0. The gas to be expanded from the source Q flows via a gas line into the at least one gas expansion device, i.e. the throttle D0 or the alternative expansion turbine, as well as into the at least one heat exchanger WT0. The expanded gas flowing out of the at least one gas expansion device also flows into the at least one heat exchanger WT0, wherein the gas to be expanded cools in the at least one heat exchanger WT0. In contrast, the gas that has cooled due to the expansion heats up in the at least one heat exchanger WT0. Finally, the expanded and heated gas flows via a first gas line to the gas sink S1.The gas to be expanded and cooled flows to a further use, namely to stage II. At this point, stage II shown here corresponds to stages II in the figures . Figure 2 and Figure 3 , whereby the optional interconnection with the stages III and IV, as shown in the figures Figure 2 and Figure 3 explained.

[0042] The electrical power generated by the optional expansion turbines ( ) can be used to operate the compressor V1.

[0043] The invention is characterized by the fact that the gas from source Q is already under high pressure in the reservoir and has not suffered any significant pressure loss from the reservoir to the gas expansion plant. During expansion in generic gas expansion plants, the gas cools down considerably, which is undesirable. According to the invention presented here, the heat for heating the expanded gas comes from the high-pressure gas itself. During expansion, the gas also drives an expansion turbine for generating electrical power. The thermal energy and also the energy extracted for electrical power have been partially extracted from the pressurized gas, namely the part that becomes liquefied gas (LNG). The invention presented here is characterized by the utilization of the energy present in the pressurized gas.The gas expansion system proposed here thus operates, unlike the state of the art, without the supply of external heat energy. Instead, the gas expansion system presented here generates electrical energy and, at least optionally, liquefied natural gas (LNG). LIST OF REFERENCE SYMBOLS 10 vortex tube LSL Low-boiling line 11 inlet MDG Medium pressure gas 12 Outlet (KF) N 2 Nitrogen 13 Outlet (WF) Q Gas source 100 Gas expansion system RW pipe wall 200 Gas expansion system S1 Alley depression 300 Gas expansion system S2 Alley depression CNG compressed gas SG Boiling gas D0 throttle SGL1 Boiling gas pipeline D1 throttle SGL2 Boiling gas pipeline D1A Exit SGL3 Boiling gas pipeline D2 throttle SP1 separator D2A Exit SP2 separator FG1 LPG pipeline V1 compressor GH Gas, high pressure side WT0 heat exchanger GT gas tank WT1 heat exchanger H 2 hydrogen WT2 heat exchanger KF Cold fraction WT3 heat exchanger LNG liquid gas W1 vortex LN2 liquid nitrogen W2 vortex WF Warm fraction WT0A1 Exit I Level WT0A2 Exit II Level WT1A1 Exit III Level WT1A2 Exit IV Level WT1L1 Line WT1L2 Line manometer thermometer cold electrical current

Claims

1. A gas expansion installation (200) for the expansion and amount control of gas for use between - a first gas source (Q), located upstream of the gas flow, such as a gas tank, a medium-pressure gas network or high-pressure gas network or a cavern storage facility, and - at least one second gas sink (S1), located downstream of the gas flow, such as a consumer, a medium-pressure gas network with a lower pressure or a gas supply line, comprising a first gas line for connection to the gas sink (S1) one gas line each, which is connected - with a gas expansion device and - at least one heat exchanger (WT1) and in a first stage (I) - at least one gas expansion device, such as a throttle, a vortex tube (10) or an expansion turbine (D0) and - at least one first heat exchanger (WT1), are available, wherein the gas to be expanded flows from the gas source via the respective gas line both into the at least one gas expansion device and into the at least one first heat exchanger (WT1), wherein the expanded gas flowing out of the at least one gas expansion device also flows into the at least one first heat exchanger (WT1) and wherein the gas to be expanded from the gas source cools down in the at least one first heat exchanger (WT1) and the gas having cooled down because of the expansion heats up in the at least one first heat exchanger (WT1), wherein the expanded gas which has heated up can flow via the first gas line to the gas sink (S1), wherein a second outlet (WT1A2) of the first heat exchanger (WT1) for the gas from the gas source (Q) which is to be expanded and has cooled and flowed through the first heat exchanger (WT1) opens into two lines (WT1L1, WT1L2), wherein the system has a first line (WT1L1) and a second line (WT1L2), a further throttle (D1) or an expansion turbine and a second heat exchanger (WT2), and a) the first line (WT1L1) is in flow connection with the further throttle (D1) or the expansion turbine, and b) the second line (WT1L2) is in flow connection with the second heat exchanger (WT2), wherein, downstream, the further throttle (D1) or the expansion turbine is also in flow connection with the second heat exchanger (WT2), whereby the gas having flowed through the further throttle (D1) or the expansion turbine and having cooled down in the process takes up heat as a medium-pressure gas (MDG) which has passed through the first line (WT1L1) from the gas which has passed through the second line (WTL2) and wherein the path of the medium-pressure gas (MDG) can be connected via a first outlet (WT2A1) of the second heat exchanger (WT2) to a further gas sink (S2) located downstream of the gas flow, wherein the system has a third throttle (D2) or a further expansion turbine and a first separator (SP1) and a second outlet (WT2A2) of the second heat exchanger (WT2) for the gas which has previously passed through the second line (WT1L2) to the second heat exchanger (WT2), is in flow connection with the third throttle (D2) or the further expansion turbine, wherein the downstream outlet (D2A) of the third throttle (D2) or the further expansion turbine is in flow connection with the first separator (SP1), which separates liquid gas (LNG) from boiling gas (SG), characterized in that the system has a third heat exchanger (WT3) and a second boiling gas line (SGL2) and the boiling gas (SG) is fed via the second boiling gas line (SGL2) to the third heat exchanger (WT3), through which liquid nitrogen (LN2) flows, wherein the liquid nitrogen (LN2) liquefies the boiling gas (SG) and in so doing passes into the gas space as gaseous nitrogen (N2), and wherein the system has a third boiling gas line (SGL3) and a second separator (SP2) and the liquefied boiling gas (SG) is fed via the third boiling gas line (SGL3) to the second separator (SP2), which separates liquefied gas (LNG) from non-liquefied gas components, such as hydrogen (H2) and / or noble gases (He, Ar).

2. Gas expansion system according to claim 1, characterized in that the at least one gas expansion device has at least one first vortex tube (10), wherein the first vortex tube (10) can be brought into flow connection with the first gas source (Q) located upstream of the gas flow via an inlet, and wherein the gas can flow from the gas source (Q) into the at least one first vortex tube (10) into a tangential inlet (11), and flows out from two outlets in the form of a first outlet (12) for a first cold fraction (KF) of the gas and in the form of a second outlet (13) for a second warm fraction (WF) of the gas, the cold fraction (KF) of the gas flowing out of the first outlet (12) of the at least one vortex tube (10) is in flow connection with the first heat exchanger (WT1), which can be brought into flow connection with the first gas source (Q) located upstream of the gas flow, wherein wherein the cold fraction (KF) of the at least one vortex tube (10) absorbs heat from the gas to be expanded from the gas source (Q) when flowing through the first heat exchanger (WT1), and is heated in the process, and wherein a first outlet (WT1A1) of the first heat exchanger (WT1) is in flow connection with the second outlet (13) for the second warm fraction (WF) of the at least one vortex tube (10), whereby the cold fraction (KF) of the at least one vortex tube (10) heated in the first heat exchanger (WT1) is combined with the second warm fraction (WF) of the at least one vortex tube (10).

3. Gas expansion system according to one of claims 1 and 2, characterized in that the system comprises a liquid gas line (FG1) and the liquid gas (LNG) of the first separator (SP1) is combined with the liquid gas (LNG) of the second separator (SP2) via the liquid gas line (FG1), which connects the two separators (SP1, SP2) on the liquid side.

4. Gas expansion system according to one of claims 1 to 3, characterized in that the system comprises a low-boiling line (LSL1) and a gas tank (GT) and the non-liquefied gas components (H2, He, Ar) can be fed into the gas tank (GT) via the low-boiling line (LSL) between the second separator (SP2) and the gas tank (GT).

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