Device for generating energy from compressed air, system comprising such a device and method for operating such a system

Abstract

A device for generating energy from compressed air, having an air turbine (16) equipped to expand gaseous air starting from a first pressure level to a second pressure level and during which first energy is generated, having a combustion chamber (17) equipped to receive the air expanded in the air turbine, the combustion chamber (17) is provided with an air turbine (18), in which the fuel is combusted, and an exhaust gas turbine (18), which is equipped to expand the exhaust gas generated during the combustion of the fuel in the combustion chamber (17) and to generate a second energy during the process, at least the air turbine and the exhaust gas turbine having a common housing.

Description

Technical Field

[0001] The present invention relates to a device for generating energy from compressed air, a system having such a device, and a method for operating the system. Background Art

[0002] In practice, liquid air energy storage (LAES) devices and compressed air energy storage (CAES) devices are known for storing energy for subsequent use. Thus, in a liquid air energy storage device, liquid air is stored in a memory and can be evaporated in an evaporator. The evaporated air is then guided through an air turbine so as to expand in the air turbine and generate mechanical energy in the process, which can then be utilized, for example, to drive a generator or other machine and thus generate electrical energy. In a compressed air energy storage device, compressed gaseous air is stored, which can likewise be guided through an air turbine to extract the mechanical energy in the air turbine again, which can then be utilized, for example, to drive a generator and thus generate electrical energy. The liquid air energy storage (LAES) devices and compressed air energy storage (CAES) devices known from practice have limited efficiency. There is a need for a device for generating energy from compressed air with higher efficiency. Summary of the Invention

[0003] Starting from this, the present invention is based on the following object: to create a novel device for generating energy from compressed air, a system having such a device, and a method for operating the system.

[0004] This object is achieved by a device for generating energy from compressed air according to claim 1, a system according to claim 10 or claim 11, and a method according to claim 13.

[0005] The device for generating energy from compressed air includes an air turbine configured to expand gaseous air from a first pressure level to a second pressure level and generate first energy in the process.

[0006] The device for generating energy from compressed air further includes a combustion chamber configured to receive the air expanded in the air turbine and burn fuel therein.

[0007] The device for generating energy from compressed air further includes an exhaust gas turbine configured to expand the exhaust gas generated during the combustion of fuel in the combustion chamber and generate second energy in the process.

[0008] At least the air turbine and the exhaust gas turbine have a common housing.

[0009] With the aid of a device for generating energy from compressed air according to the invention, energy can be generated from compressed air with high efficiency, which compressed air is provided, for example, by a liquid air energy storage (LAES) device or a compressed air energy storage (CAES) device. In this process, the compressed air is first expanded in an air turbine to a first pressure level and then fed to a combustion chamber, in which fuel burns in the presence of the air expanded to the first pressure level and thus exhaust gas is generated, which is guided via an exhaust gas turbine in order to thereby generate further energy. Thus, energy (i.e., mechanical energy) is generated both in the air turbine and in the exhaust gas turbine, which energy can be utilized, for example, to drive a generator to generate electrical energy.

[0010] Compared with a simple air turbine, more than twice the effective power can be generated using the device according to the invention. Thus, energy can be generated from compressed air with high efficiency.

[0011] Preferably, the air turbine, the combustion chamber and the exhaust gas turbine comprise a common housing. Alternatively, the air turbine and the exhaust gas turbine comprise a common housing and the combustion chamber comprises a separate housing. In particular when the air turbine, the combustion chamber and the exhaust gas turbine comprise a common housing, the device can be implemented in a particularly compact manner with low installation space requirements and low weight. Thus, the arrangement of the air turbine, the combustion chamber and the exhaust gas turbine can be particularly flexible and efficient in a liquid air energy storage (LAES) device or a compressed air energy storage (CAES) device. In particular when the combustion chamber is arranged in a separate housing, the installation space requirements and the weight of the device increase, but the thermal stress on the common housing of the air turbine and the exhaust gas turbine can be reduced.

[0012] Preferably, the device for generating energy from compressed air comprises a first heat exchanger connected between the air turbine and the combustion chamber, through which on the one hand the air expanded in the air turbine and the air to be fed to the combustion chamber and on the other hand the exhaust gas expanded in the exhaust gas turbine can be guided in order to heat the air expanded in the air turbine upstream of the combustion chamber. By means of the first heat exchanger, the temperature of the air expanded in the first air turbine is increased, whereby the amount of fuel required in the combustion chamber can be reduced. Thus, the efficiency of the device according to the invention can be further increased.

[0013] Preferably, the device for generating energy from compressed air includes a second heat exchanger connected upstream of the air turbine, through which on the one hand the air to be expanded in the air turbine and on the other hand the exhaust gas expanded in the exhaust gas turbine can be guided in order to heat the air to be expanded in the air turbine upstream of the air turbine. By means of the second heat exchanger connected upstream of the air turbine, the efficiency of the device for generating energy from compressed air can also be further increased. Thus, by increasing the temperature of the air to be expanded in the air turbine, more energy can be generated in the air turbine.

[0014] Preferably, the air turbine and the exhaust gas turbine are arranged back-to-back so oriented that the inlet sides of the two turbines point away from each other, and the outlet sides of the two turbines face each other. The back-to-back arrangement of the two turbines allows for a favorable thermal balance of at least the common housing of the air turbine and the exhaust gas turbine and the shafts driven by the air turbine and the exhaust gas turbine. Alternatively, the air turbine and the exhaust gas turbine are arranged in-line so oriented that the outlet side of one of the two turbines faces the inlet side of the other of the two turbines.

[0015] The system according to the invention includes a device for generating energy from compressed air according to the invention and preferably a liquid air energy storage (LAES) device, which includes a memory for storing liquid air and an evaporator for evaporating the liquid air, wherein the evaporated air can be conveyed as gaseous compressed air to the air turbine. The device for generating energy from compressed air according to the invention is preferably used in combination with a liquid air energy storage (LAES) device in order to generate energy from liquid air.

[0016] In addition to the liquid air energy storage (LAES) device, the system according to the invention can also include a compressed air energy storage (CAES) device. Description of the Drawings

[0017] Preferred further developments of the invention are obtained from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail by means of the drawings, without being limited thereto. Here:

[0018] Figure 1 A first system having a device for generating energy from compressed air according to the invention is shown,

[0019] Figure 2 A second system having a second device for generating energy from compressed air according to the invention is shown,

[0020] Figure 3 A third system having a third device for generating energy from compressed air according to the invention is shown. Detailed implementation mode

[0021] The device relates to a device 10 for generating energy from compressed air. Figure 1 The device 10 according to the invention, which is shown, is connected to a liquid air energy storage (LAES) device 11 and an electric motor 12.

[0022] The LAES device 11 has a memory 13 for storing liquid air. In addition, in the exemplary embodiment shown, the LAES device 11 includes a pump 14, which is configured to supply liquid air to the evaporator 15 of the LAES device 11. In the evaporator 15, the liquid air can be evaporated so as to thereby provide compressed gaseous air, and then energy can be generated from the compressed gaseous air by means of the device 10. In Figure 1 this, for example, the energy is utilized to drive the electric motor 12.

[0023] The pump 14 is optional for the LAES device 11. The liquid air can also be extracted from the memory 13 and conveyed to the evaporator 15 in another way. In particular, when the pump 14 is present, it can be implemented as a cryogenic pump.

[0024] The device 10 according to the invention for generating energy from compressed air includes an air turbine 16. The air turbine 16 is configured to expand compressed air from a first pressure level to a second pressure level and generate first energy in the process.

[0025] In addition, the device 10 according to the invention for generating energy from compressed air includes a combustion chamber 17. The combustion chamber 17 is configured to receive the air expanded in the air turbine 16 and burn fuel therein in the presence of air and generate exhaust gas in the process. The fuel to be burned is ignited in the combustion chamber 17.

[0026] The device 10 according to the invention for generating energy from compressed air further includes an exhaust gas turbine 18. The exhaust gas turbine 18 is configured to expand the exhaust gas generated during the combustion of fuel in the combustion chamber 17 and generate second energy in the process.

[0027] Preferably, the air turbine 16 and the exhaust gas turbine 18 drive a common shaft 22 and jointly drive the electric motor 12 via the common shaft 22. In the process, the electric motor 12 preferably operates as a generator so as to thereby provide electrical energy.

[0028] According to Figure 1, the liquid air L1 is extracted from the storage by means of the pump 14, and the liquid air is supplied by the pump 14 as liquid air L2 to the evaporator 15. Downstream of the evaporator 15, there is gaseous compressed air L3, which flows through the air turbine 16, where the gaseous air L4 expanded to the second pressure level leaves the air turbine 16. The air L4 at the second pressure level is conveyed to the combustion chamber 17, i.e., together with the fuel K, where waste gas is generated during the combustion of the fuel K, which leaves the combustion chamber 17 as waste gas A1 and expands in the waste gas turbine 18. The expanded waste gas A2 is discharged from the waste gas turbine 18.

[0029] In Figure 1 , the device 10 includes a first heat exchanger 19, which is connected between the air turbine 16 and the combustion chamber 17. The air L4 expanded in the air turbine on the one hand and the waste gas A2 expanded in the waste gas turbine 18 on the other hand are guided through the first heat exchanger 19 so as to transfer the thermal energy of the waste gas A2 to the expanded air L4 and thereby increase the temperature of the expanded air upstream of the combustion chamber 17. In this way, the efficiency of the device 10 for generating energy from compressed air according to the present invention can be increased.

[0030] Figure 2 The block diagram of the second device 10 according to the present invention for generating electrical energy from compressed air together with the LAES device 11 is shown, where, in order to avoid Figure 2 unnecessary repetitions in Figure 1 , the same reference numerals are used for the same components as in Figure 1 , and reference is made in this regard to the explanation regarding Figure 2 . Only the details in which the exemplary embodiment of Figure 1 differs from the exemplary embodiment of

[0031] In Figure 1 , the air turbine 16, the waste gas turbine 18, the combustion chamber 17 and the first heat exchanger 19 have a common housing 20. Thus, a particularly compact, space-saving and weight-reducing design can be ensured. In contrast, in Figure 2 , only the air turbine 16, the waste gas turbine 18 and the combustion chamber 17 have a common housing 20, while the first heat exchanger 19 is not integrated in the common housing 20 but is implemented as a separate component with a separate housing.

[0032] Figure 2 Compared with Figure 1Another difference is that the exhaust gas A2 (which expands in the exhaust gas turbine 18) guided through the first heat exchanger 19 is subsequently guided as exhaust gas A3 through the second heat exchanger 21, which is arranged upstream of the air turbine 16 in the flow direction of the air expanding in the air turbine 16. On the one hand, the compressed gaseous air L3 and on the other hand the exhaust gas A3 are guided through this second heat exchanger 21 in order to heat the air L3 to be expanded in the air turbine 16 upstream of the air turbine 16. The efficiency can thereby be further increased.

[0033] Figure 3 Figure 4 shows another device 10 for generating energy from compressed air according to the invention, wherein the LAES device 11 is also shown again in Figure 3 and, in order to avoid unnecessary repetition, the same reference numerals are used for the same components as in Figure 1 and only the details in which the exemplary embodiment of Figure 3 differs from the exemplary embodiment of Figure 1 will be discussed below.

[0034] In the Figure 3 exemplary embodiment, only the air turbine 16 and the exhaust gas turbine 18 have a common housing 20. In Figure 3 , the first heat exchanger 19 and the combustion chamber 17 are not integrated in the common housing 20 but are implemented as separate components with separate housings. In this way, the common housing 20 of the air turbine 16 and the exhaust gas turbine 18 is subjected to a lower thermal load than in Figure 1 and is the same as the thermal load in Figure 2 , so that thermal deformation can thus be reduced. This is advantageous for the shaft 22 driven by the two turbines 16, 18 via which the electric machine 12 is driven.

[0035] For the present invention here, the compressed gaseous air L3 provided by the LAES device 11 in the shown exemplary embodiment is expanded to the pressure level of the combustion chamber pressure of the combustion chamber 17.

[0036] Different from the shown exemplary embodiment, the compressed gaseous air can also be provided by a compressed air energy storage (CAES) device.

[0037] For the CAES device, the evaporator 15 is dispensed with. Instead of the pump 14, a compressor can be present for the CAES device.

[0038] Air is supplied to combustion chamber 17 in order to burn fuel K in combustion chamber 17, wherein, in the process, exhaust gas A1 is generated in combustion chamber 17, and this exhaust gas is guided through exhaust gas turbine 18 for expansion. Thus, mechanical energy is generated in air turbine 16 and exhaust gas turbine 18 respectively, and this mechanical energy is used to drive a common shaft 22 of an electric machine 12 preferably in the form of a generator, so as to generate electric energy thereby.

[0039] Through the combustion of fuel K, thermal energy is supplied to the air expanding in air turbine 16, wherein the exhaust gas A1 expands to ambient pressure in exhaust gas turbine 18. The waste heat of exhaust gas A2 can be utilized in at least one heat exchanger 19, 21 in order to heat the air L4 expanding in air turbine 16 and / or the air L3 to be expanded in air turbine 16.

[0040] With the present invention, significantly more power can be output than with a pure air turbine combined with an LAES device or a CAES device. Thus, approximately more than twice the power can be output.

[0041] In Figures 1 to 3 an exemplary embodiment, the heat of the exhaust gas can be used to preheat fuel K.

[0042] Alternatively or additionally, it is also possible that the exhaust gas leaving exhaust gas turbine 18 is guided through evaporator 15 for the LAES device 11, so as to utilize the heat of the exhaust gas in the region of evaporator 15 thereby.

[0043] Especially when there is an LAES device 11, liquid air can be used to cool components, such as combustion chamber 17, so as to achieve a higher combustion temperature or operating temperature. Alternatively or additionally, liquid air can be utilized to adjust the air or exhaust gas temperature or mass flow rate and / or optimize fuel combustion and / or reduce emissions.

[0044] Preferably, air turbine 16 and exhaust gas turbine 18 are arranged back-to-back and oriented such that the inlet sides of the two turbines 16, 18 point away from each other, and the outlet sides of the two turbines 16, 18 face each other. This back-to-back arrangement of the two turbines 16, 18 is not shown in Figures 1 to 3 which allows a favorable thermal balance of at least the common housing of air turbine 16 and exhaust gas turbine 18 and the shaft 22 driven by air turbine 16 and exhaust gas turbine 20.

[0045] The present invention allows for the efficient generation of energy from compressed air.

[0046] Furthermore, the present invention relates to a method for operating a system of a device 10, a CAES device or an LAES device 11 and an electric machine 12 coupled to an electric power network.

[0047] In particular, when the network frequency of the electrical power network is less than a set value, the motor 12 operates as a generator for the network stability of the electrical power network 12. In this case, for network stability, the mechanical energy generated in the device 10 during the power generation phase is converted into electrical energy and transmitted to the power network. In this case, the CAES device or the LAES device 11 is connected to the device 10.

[0048] In particular, when the network frequency of the electrical power network is greater than a set value, the motor 12 operates as a motor for the network stability of the electrical power network. In this case, for network stability, the electrical energy is converted into power loss. In this case, the CAES device or the LAES device 11 is preferably disconnected from the device 10. In particular, when the CAES device or the LAES device 11 is disconnected from the device 10, the motor 12 preferably operates at the minimum rotational speed so as to switch to the next power generation phase of electrical energy in a very short time.

[0049] Therefore, the present invention also relates to an application of a system of the device 10, the CAES device or the LAES device 11, and the motor 12 for the network stability of the electrical power network to which the motor 12 is connected.

[0050] List of reference numerals

[0051] 10 Device

[0052] 11 LAES device

[0053] 12 Motor

[0054] 13 Memory

[0055] 14 Pump

[0056] 15 Evaporator

[0057] 16 Air turbine

[0058] 17 Combustion chamber

[0059] 18 Exhaust gas turbine

[0060] 19 First heat exchanger

[0061] 20 Housing

[0062] 21 Second heat exchanger

[0063] 22 Shaft

Claims

1. A device for generating energy from compressed air, wherein An air turbine (16) is provided, which is configured to expand gaseous air starting from a first pressure level to a second pressure level and to generate first energy in the process, having a combustion chamber (17) configured to receive air expanded in the air turbine and to combust fuel therein, having an exhaust gas turbine (18) which is configured to expand the exhaust gases produced during the combustion of the fuel in the combustion chamber (17) and to generate a second energy in the process, in, At least the air turbine (16) and the exhaust gas turbine (18) have a common housing (20).

2. The device according to claim 1, characterized in that The air turbine (16), the combustion chamber (17) and the exhaust gas turbine (18) comprise a common housing (20).

3. The device according to claim 1, characterized in that The air turbine (16) and the exhaust gas turbine (18) comprise a common housing (20), and the combustion chamber (17) has a separate housing.

4. The device according to any one of claims 1 to 3, characterized in that A first heat exchanger (19) is connected between the air turbine (16) and the combustion chamber (17), through which on the one hand the air expanded in the air turbine (16) and to be supplied to the combustion chamber (17) and on the other hand the exhaust gas expanded in the exhaust gas turbine (18) can be conducted in order to heat the air expanded in the air turbine (16) upstream of the combustion chamber (17).

5. The device according to any one of claims 1 to 4, characterized in that A second heat exchanger (21) is connected upstream of the air turbine (16), through which air expanded in the air turbine (16) on the one hand and exhaust gas expanded in the exhaust gas turbine (18) on the other hand can be conducted in order to heat the air expanded in the air turbine (16) upstream of the air turbine (16).

6. The device according to claims 4 and 5, characterized in that The first heat exchanger (19) is equipped to receive the exhaust gas expanded in the exhaust gas turbine (18) and then supply it to the second heat exchanger (21).

7. The device according to claim 4, 5 or 6, characterized in that The first heat exchanger (19) is arranged in the common housing (20).

8. The device according to any one of claims 1 to 7, characterized in that The air turbine (16) and the exhaust gas turbine (18) are oriented in a back-to-back arrangement such that the inlet sides of the two turbines (16, 18) point away from each other and the outlet sides of the two turbines (16, 18) face each other.

9. The device according to any one of claims 1 to 8, characterized in that The air turbine (16) and the exhaust gas turbine (18) are oriented in a serial arrangement such that the outlet side of one of the two turbines (16) faces the inlet side of the other of the two turbines (18).

10. A system having a device (10) according to any one of claims 1 to 9 and a liquid air energy storage device (11), the liquid air energy storage device comprising a reservoir (13) for storing liquid air and an evaporator (15) for evaporating the liquid air, wherein: The evaporated air can be delivered to the air turbine (16).

11. A system having a device (10) according to any one of claims 1 to 9 and a compressed air energy storage device, the compressed air energy storage device comprising a storage device for storing compressed gaseous air, wherein: The compressed gaseous air can be delivered to the air turbine.

12. The system according to claim 11, characterized in that An electrical machine (12) coupled to a device (10) according to any one of claims 1 to 9, the electrical machine being operable both as a motor and as a generator.

13. A method for operating a system according to claim 12, wherein: In order to stabilize the network of the electric power network coupled to the electric machine (12), in particular when the network frequency of the electric power network is greater than a set value, the electric machine (12) is operated as a motor, or in particular when the network frequency of the electric power network is less than a set value, the electric machine (12) is operated as a generator.

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