EP3037764A1 - Method and combination system for storing and recovering energy - Google Patents

Abstract

The present invention relates to a method of storing and recovering energy using a combination plant (100) comprising a gas treatment unit (110) and a power generation unit (120), wherein in a first operating mode, compressed feed gas used in a heat exchange system (10). is cooled, a cryogenic gas liquefaction product is produced and a storage liquid is provided using the gas liquefaction product, and in a second mode of operation using the storage liquid, a cryogenic process liquid is provided which is heated in the heat exchange system (10) to obtain a pressurized fluid in the energy production unit (120) work is relaxed. It is provided that the compressed feed gas is cooled in a first heat exchange unit (11) of the heat exchange system (10) in the first operating mode in countercurrent to a heat transfer fluid and the process liquid in the first heat exchange unit (11) in the second operating mode in countercurrent to the heat transfer fluid is, and the heat transfer fluid at least partially by means of at least two further heat exchange units (16, 18) of the heat exchange system (10), which are operated at different temperatures and each with at least one organic refrigerant, cooled in the first operating mode and heated in the second operating mode , The directions in which the heat transfer fluid and the feed gas are passed through the first heat exchange unit (11) in the first operation mode are opposite to the directions in which the heat transfer fluid and the process liquid are passed therethrough in the second operation mode and the heat transfer fluid and compressed feed gases are each passed through the heat exchange unit (11) at first pressure levels and the heat transfer fluid and the process fluid at second pressure levels, the first pressure levels being at least 5 bar above the second pressure level. A corresponding combination system (100) is also an object of the invention.

Description

The present invention relates to a method and a combination plant for storing and recovering energy, in particular electrical energy, according to the preambles of the respective independent claims.

State of the art

For example, from the DE 31 39 567 A1 and the EP 1 989 400 A1 It is known to use liquid air or liquid nitrogen, ie cryogenic air liquefaction products, for grid control and provision of control power in power grids.

At low-flow times or excess power periods in which electricity is available at low cost, compressed feed air in an air separation plant with an integrated condenser or in a dedicated air liquefaction plant, here generally, as explained below, also referred to as air treatment unit, in whole or in part to such a cryogenic air liquefaction product liquefied. The cryogenic air liquefaction product is stored as cryogenic storage liquid in a storage system with cryogenic tanks. In addition to the cryogenic air liquefaction product, other cryogenic fluids can also be stored in the storage system. This mode of operation occurs during a period of time, referred to herein as the energy storage period.

At peak load times, a cryogenic process fluid is formed from the cryogenic storage fluid, which may also comprise other cryogenic fluids. The cryogenic process liquid is warmed up, if necessary after increasing the pressure by means of a pump, to about ambient temperature or higher and thus converted into a gaseous or supercritical state. An obtained pressure stream is expanded in an energy recovery unit in one or more expansion turbines with reheating to ambient pressure. The released mechanical power is converted into electrical energy in one or more generators of the power generation unit and converted into electrical energy Fed into the grid. This mode of operation occurs during a period of time, referred to herein as the energy recovery period.

The released during the transfer of the cryogenic process liquid in the gaseous or supercritical state during the energy recovery period cold can be stored and used during the energy storage period to provide cold for the recovery of the air liquefaction product. So is out of the WO 2014/026738 A2 It is known to cool the compressed feed air used to obtain the air liquefaction product in the energy storage period countercurrent to two cooled organic refrigerants at two different temperature levels and to heat the described cryogenic process liquid against the then heated refrigerant in the energy recovery period, whereby the refrigerant is cooled again.

There are also known compressed air storage power plants in which air is not liquefied, but compressed in a compressor and stored in an underground cavern. In times of high electricity demand, the compressed air from the cavern is directed into the combustion chamber of a gas turbine. At the same time, the gas turbine is supplied via a gas line fuel, such as natural gas, and burned in the atmosphere formed by the compressed air. The formed exhaust gas is expanded in the gas turbine, thereby generating energy. The present invention is further to be distinguished from methods and apparatus in which an oxygen-rich fluid is introduced to promote oxidation reactions in a gas turbine. Corresponding methods and devices operate with air liquefaction products containing greater than 40 mole percent oxygen.

The known from the prior art method for storing and recovering energy, in particular electrical energy, often prove to be not sufficiently efficient. Furthermore, flammable fluids such as hydrocarbons, alcohols, etc. are used here as organic refrigerants. In the from the WO 2014/026738 A2 known methods, these and the compressed feed air or the cryogenic process liquid are each guided through separate heat exchanger passages of one or more common countercurrent heat exchanger. As appropriate combustible fluids but at Leakage can come into contact with oxygen-containing fluids, complex safety measures are required.

From the US Pat. No. 6,295,837 B1 Although it is basically known to use an inert gas (for example, nitrogen or a noble gas such as argon) as a refrigerant in a refrigeration cycle. However, cold gas from liquefied natural gas is continuously transferred via a corresponding refrigeration cycle by means of heat exchangers to a stream to be cooled and compressed in or upstream of an air separation plant and the natural gas is vaporized in the process. This is the US Pat. No. 6,295,837 B1 as explicitly stated there, specifically tailored to combined gasification combined cycle (IGCC) processes, where nitrogen and oxygen are continuously required at high pressure, typically greater than 10 bar, and at the same time the vaporized natural gas as Secondary fuel can be used to heat. For a process for the storage and recovery of energy that is suitable in the US Pat. No. 6,295,837 B1 proposed method not because it provides only a cold transfer in one direction. This also applies to a procedure that is in the US 3,058,314 A is disclosed.

Also from the US 2014/0245756 A1 Cryogenic energy storage systems and methods for storing refrigeration energy and their reuse are disclosed.

The present invention therefore has as its object to provide an efficient and safety-simpler method for storing and recovering energy, for example using an air liquefaction product.

Disclosure of the invention

Against this background, the present invention proposes a method for storing and recovering energy and a corresponding combination system with the features of the independent patent claims. Preferred embodiments are the subject of the dependent claims and the following description.

Before explaining the advantages that can be achieved within the scope of the present invention, its technical principles and some terms used in this application are explained in more detail.

A "power generation unit" is understood here to mean a plant or a plant part which is or is set up for generating electrical energy. In the context of the present invention, an energy-generating unit comprises at least one expansion turbine, which is advantageously coupled to at least one electric generator. A relaxation machine coupled to at least one electric generator is commonly referred to as a "generator turbine". The mechanical power released during the expansion of a pressurized fluid in the at least one expansion turbine or generator turbine can be converted into electrical energy in the energy generation unit.

The production of air products in the liquid or gaseous state by cryogenic separation of air in air separation plants is known and, for example at H.-W. Haring (ed.), Industrial Gases Processing, Wiley-VCH, 2006 , in particular Section 2.2.5, "Cryogenic Rectification" described. Air separation plants have distillation column systems which can be designed, for example, as two-column systems, in particular as classic Linde double-column systems, but also as three-column or multi-column systems. In addition to the distillation columns for the recovery of nitrogen and / or oxygen in the liquid and / or gaseous state (for example, liquid oxygen, LOX, gaseous oxygen, GOX, liquid nitrogen, LIN and / or gaseous nitrogen, GAN), so the distillation columns for nitrogen-oxygen Separation, distillation columns can be provided for obtaining further air components, in particular the noble gases krypton, xenon and / or argon.

The present invention may include recovering an air liquefaction product using compressed feed air. The plant components used for this purpose can be summarized under the term "air treatment unit". This is understood in the parlance of the present application, a plant which is set up to obtain at least one air liquefaction product using compressed feed air. Sufficient for an air treatment unit for use in the present The invention is that it can be obtained by this a corresponding cryogenic air liquefaction product, which can be used as a storage liquid and transferred to a storage system. This may be an air separation plant, as explained above, but also merely a pure "air liquefaction plant" which does not have a distillation column system. Incidentally, the structure of an air liquefaction plant may correspond to that of an air separation plant with the discharge of an air liquefaction product. Of course, liquid air can also be produced as an air liquefaction product in an air separation plant. Since, according to the invention, a gas other than air can also be used, a corresponding system is also referred to more generally herein as a "gas treatment unit".

The provision of the compressed feed air, from which the air liquefaction product is produced in respective air treatment units, can take place in a known main (air) compressor with booster or any other air-conditioning device of the type used in conventional air separation plants. For details refer to the literature cited with reference to air separation plants.

An "air product" is any product that can be produced, at least by compressing and cooling air, and in particular, but not necessarily, by subsequent cryogenic rectification. In particular, these may be liquid or gaseous oxygen (LOX, GOX), liquid or gaseous nitrogen (LIN, GAN), liquid or gaseous argon (LAR, GAR), liquid or gaseous xenon, liquid or gaseous krypton, liquid or gaseous neon , liquid or gaseous helium, etc. but also, for example, liquid air (LAIR). The terms "oxygen", "nitrogen", etc., also refer to cryogenic liquids or gases which have the respective air component in an amount which is above that of atmospheric air, so they do not have to be pure liquids or gases with high contents Accordingly, an "air liquefaction product" is understood to mean a corresponding liquid product at cryogenic temperature, and the same applies to a "gas product" or "gas liquefaction product" which can not be produced from or not only from air but also from another gas.

A "heat exchanger" serves to indirectly transfer heat between at least two e.g. in countercurrent flow, such as a warm compressed air stream and one or more cold streams or a cryogenic liquid air product and one or more hot streams. Typically countercurrent heat exchangers are used in the context of the present invention. A heat exchanger may be formed from a single or multiple heat exchanger sections connected in parallel and / or in series, e.g. from one or more plate heat exchanger blocks. In this case it is a plate heat exchanger (English: Plate Fin Heat Exchanger). Such a heat exchanger, for example, the "main heat exchanger" of an air treatment plant through which the majority of the fluids to be cooled or heated to be cooled or heated, has "passages" formed as separate fluid channels with heat exchange surfaces and parallel and through other passages separated, are combined to "passage groups". A "heat exchange unit" may include one or more heat exchanger blocks or sections.

The present application uses the terms "pressure level" and "temperature level" to characterize pressures and temperatures, thereby indicating that corresponding pressures and temperatures in a given plant need not be used in the form of exact pressure or temperature values to realize the innovative concept. However, such pressures and temperatures typically range in certain ranges that are, for example, ± 1%, 5%, 10%, 20% or even 50% about an average. Corresponding pressure levels and temperature levels can be in disjoint areas or in areas that overlap one another. In particular, for example, pressure levels include unavoidable or expected pressure drops, for example, due to cooling effects. The same applies to temperature levels. The pressure levels indicated here in bar are absolute pressures.

Advantages of the invention

The present invention has been described above and will be described below with reference to air as a working medium. However, it is also suitable for use with other, similarly liquefiable media, for example nitrogen, oxygen, argon and mixtures of these gases.

The present invention is based on a method of storing and recovering energy using a combination plant comprising a gas treatment unit and a power generation unit. As is generally known, in a corresponding combination plant in a first operating mode of compressed feed gas which is cooled in a heat exchange system of the gas treatment unit, a cryogenic gas liquefaction product can be produced and a storage liquid can be provided using the gas liquefaction product. If compressed feed air is used as compressed feed gas, the gas treatment unit is an air treatment unit. However, as mentioned, the invention is not limited to the use of air. As already mentioned, the storage liquid can be, for example, a corresponding liquid gas. The use of compressed feed air as compressed feed gas is in particular liquid air and / or any other liquid air product which can be formed from appropriately compressed feed air.

Furthermore, such a method comprises, in a second operating mode using the storage liquid, providing a cryogenic process liquid which is heated in the heat exchange system to obtain a pressurized fluid, which is subsequently expanded to perform work in the energy production unit, for example, a generator turbine there. The second operating mode may, for example, directly connect to the first operating mode, but other operating modes may be provided between the first and the second operating mode. In that regard, the method proposed according to the invention corresponds to the state of the art, in which a liquid air product is generated from air, stored and later vaporized to a corresponding pressure fluid.

It is understood in the context of the present invention that "using the gas liquefaction product, a storage liquid is provided", it is understood that the storage liquid does not have to be formed exclusively from the gas liquefaction product, including, for example, external, cryogenic liquefaction products or other streams may be provided, ie for example be fed into a corresponding storage system. Accordingly, the phrase that "using the storage liquid provides a cryogenic process liquid" is intended to include that the cryogenic process liquid may also be provided using additional, including, for example, external, cryogenic liquefaction products or other streams.

The invention provides to cool the compressed feed gas in a first heat exchange unit of the heat exchange system in the first operating mode in countercurrent to a heat transfer fluid and to heat the process liquid in the first heat exchange unit in the second operating mode in countercurrent to the heat transfer fluid. The use of a heat transfer fluid in the present invention has the particular advantage that additional organic refrigerants, which, as mentioned, may contain flammable hydrocarbons are not passed through the same heat exchanger as the compressed feed gas or the process liquid and therefore not in leaks with oxygen may come into contact, which is optionally contained in the compressed feed gas or the process liquid. For this purpose, the heat transfer fluid used is preferably free of or poor in oxidizing and combustible components, in particular oxygen-free in the sense explained below. The heat transfer fluid is thus advantageously neither fire-promoting nor self-combustible, "fire-promoting" a property of a fluid is understood to maintain under the prevailing conditions in a corresponding heat exchanger combustion even in the absence of atmospheric oxygen.

Furthermore, the present invention provides that the heat transfer fluid is at least partially cooled by means of at least two further, at different temperature levels and each with at least one organic refrigerant heat exchange units of the heat exchange system in the first mode of operation and heated in the second mode of operation. The operating mode referred to herein as the "first mode of operation" is the aforementioned mode of operation in the energy storage period that a corresponding combination unit performs in excess-current periods when sufficient electrical energy is available to compress gas and provide a gas liquefaction product. Correspondingly, the "second operating mode" designates the operating mode in the energy recovery period, that is to say in power-management phases in which Using the gas liquefaction product generated in the first operating mode, a corresponding pressure fluid is generated.

Further, the invention contemplates that the directions in which the heat transfer fluid and the feed gas are passed through the first heat exchange unit in the first mode of operation are opposite to the directions in which the heat transfer fluid and the process liquid are passed through the first heat exchange unit in the second mode of operation become. This allows each of the temperature profiles, according to which a cooling or heating of corresponding fluids takes place close to each other, because the heat transfer fluid and the feed gas, which flow in countercurrent to each other through the first heat exchange unit, each with the lowest possible temperature difference passed through them can be.

The invention further provides that the heat transfer fluid and the compressed feed gas in the first operating mode are each at first pressure levels and the heat transfer fluid and the process liquid in the second operating mode respectively at second pressure levels through the first heat exchange unit, the first pressure levels by at least 5 bar above the second lie. In other words, the operating pressures of the heat transfer fluid are different in the first and second modes of operation. For this purpose, a pressure control device can be provided. The pressure of the heat transfer fluid in each case depends on the pressure of the feed gas or the process fluid in the first heat exchange unit, so that a particularly effective heat transfer is also possible for this reason.

It is particularly advantageous if the first pressure levels, ie the first pressure level at which the heat transfer fluid is conducted through the first heat exchange unit in the first operating mode, and the first pressure level at which the compressed feed gas is passed through the heat exchange unit in the first operating mode , are about the same. This also applies to the second pressure levels, ie the second pressure level at which the heat transfer fluid is passed through the first heat exchange unit in the second operating mode and the second pressure level at which the process fluid is passed through the first heat exchange unit in the second operating mode. "About the same" are the Pressure levels, for example, when they do not differ by more than 20%, in particular by not more than 10%, not more than 5% or not more than 1%. "Similar levels of pressure also include identical pressure levels. At such, "approximately equal" pressure levels mentioned, particularly effective heat transfer is possible. However, it is not necessary to use exactly the same pressures.
The first pressure levels of the first operating mode are advantageously 50 to 120 bar and / or the second pressure levels of the second operating mode are advantageously 40 to 60 bar. As mentioned, the pressure difference is at least 5 bar, but the first pressure levels may also be 10, 15, 20, 30, 40, 50, 60, 70 or 80 bar above the second pressure levels.

The present invention thus provides, in addition to the storage liquid, which is provided using the compressed feed gas and stored in the first operating mode and evaporated in the second operating mode, to provide further cold storage fluids in the form of organic refrigerants. The at least two further cold storage fluids, ie the organic refrigerants, are preferably configured to store cold at different temperature levels, ie they have different boiling points, for example, which make them suitable for use at different temperatures. In this way, the cooling of the compressed feed gas in the first operating mode is particularly efficient. The same applies to the heating of the cryogenic process fluid in the second operating mode. Overall, the present invention allows a particularly efficient operation by using a total of at least three cold storage fluids, namely the gas liquefaction product formed from the compressed feed gas, using which a storage liquid is provided, and the at least two organic refrigerants, for example hydrocarbons.

Also from the US 2014/0245756 A1 As noted, cryogenic energy storage systems and methods for storing refrigeration energy and their reuse are disclosed. According to this document, in a first mode of operation, compressed air may be cooled in a cold box, thereby producing a cryogenic air liquefaction product which may be stored in a storage tank. The air liquefaction product can in a second Operating mode can be heated in a separate evaporator to obtain compressed air, which is expanded to perform work in turbines. Between the coldbox and the separate evaporator, a refrigeration cycle is provided with a heat transfer fluid. Thus, in the first mode of operation, the heat transfer fluid cools the compressed air in a first heat exchange unit, namely the cold box, countercurrently to a heat transfer fluid, and the separate evaporator heats the air liquefaction product in countercurrent to the heat transfer fluid by means of the heat transfer fluid in the second mode of operation.

In contrast, in the context of the present invention, the same heat exchange unit is used for the cooling of the compressed feed gas and the heating of the cryogenic process liquid. Another difference is that in the context of the present invention, at least two further heat exchange units, which are operated at different temperature levels and in each case with at least one organic refrigerant, are used for cooling the heat transfer fluid in the first operating mode and heating the heat transfer fluid in the second operating mode , This is not the case in the quoted text. Refrigerants that would correspond to the organic refrigerants of the present invention are absent there, as are the corresponding other heat exchange units. The heat transfer fluid is cooled in the cited document in a heat exchange unit (namely, the separate evaporator) and heated in another heat exchange unit (namely, the cold box). The further feature of the present invention, namely that the directions in which the heat transfer fluid and the feed gas are passed through the first heat exchange unit in the first mode of operation, are opposite to the directions in which the heat transfer fluid and the process liquid in the second mode of operation passed through them is also not disclosed in the cited document, because, inter alia, it is not disclosed that the same heat exchange unit is used in both cases. The same applies to the pressure levels used in the invention.

By the described features, in particular their combination, the above-mentioned and subsequently achieved advantages over the prior art, for example in the form of US 2014/0245756 A1 achieved.

As already explained, an oxygen-free or substantially oxygen-free gas mixture is advantageously used as the heat transfer fluid. It is understood that a correspondingly "oxygen-free" gas mixture may also contain residual oxygen contents, for example 1%, 0.5%, 0.1% or 0.01% oxygen or less. Correspondingly low oxygen contents sufficiently reduce the risk of ignition when in contact with a flammable organic refrigerant.

Advantageously, a fluid containing predominantly nitrogen, neon, helium and / or argon is used as the heat transfer fluid. This is particularly suitable because it is possible by the use of a corresponding fluid to set particularly high temperature profiles in the heat exchangers used and to minimize thermodynamic losses. An example of this is in the attached FIG. 5 illustrated.

Advantageously, the heat transfer fluid is at least partially evaporated during cooling of the compressed feed gas and at least partially liquefied when heating the process liquid. However, the present invention does not explicitly relate to methods in which corresponding heat transfer fluids are expanded and recompressed to thereby generate refrigeration. In the context of the present invention, a corresponding heat transfer fluid is preferably conducted in a circuit in which a maximum pressure difference of at most 5 bar, in particular at most 1 bar, 0.5 bar or less, occurs. The extraction of cold is thus not using the heat transfer fluid itself, this is only used for heat transfer, so it is not refrigerated relaxed and / or recompressed.

Advantageously, the at least two further heat exchange units comprise a second heat exchange unit, which is operated with a first organic refrigerant, which is transferred between two storage tanks. A corresponding second heat exchange unit can, compared to a third heat exchange unit, as explained below, be set up for operation at higher temperatures and operated with a corresponding organic refrigerant. This is transferred between the two storage containers, as mentioned, one of which is designed as a "warm" and a "cold" storage container. Corresponding storage containers are preferably designed as insulated tanks. In order to cool the compressed feed gas in the first operating mode, the first organic refrigerant from the "cold" storage tank is passed through the second heat exchange unit, where it cools the heat transfer fluid, and then transferred to the "warm" storage tank. Correspondingly, a transfer takes place conversely when the cryogenic process fluid is heated in the second operating mode.

In particular, halogenated or non-halogenated alkanes or alkenes, alcohols and / or aromatics, as they are known in principle, are suitable as organic refrigerants for comparatively higher temperatures. For example, halogenated or non-halogenated alkanes or alkenes such as ethane, ethylene, propane, propylene, butane, pentane, hexane and possibly also higher hydrocarbons may be used. Halogenated hydrocarbons are in particular fluorinated and / or chlorinated. Also suitable as the first organic refrigerant are alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol and other alcohols and aromatics such as toluene.

As already mentioned, the at least two further heat exchange units may advantageously comprise a third heat exchange unit operated at a lower temperature with respect to the second heat exchange unit, preferably with a second organic refrigerant transferred between two heat storage tanks and with a third organic refrigerant is transferred between two storage containers. For the explanations and the transfer of corresponding organic refrigerants, reference is made to the above explanations for the second heat exchange unit. In particular, the method according to the invention can comprise, in an advantageous embodiment, that the second and the third organic refrigerants are an identical organic refrigerant, so that the provision of different refrigerants can be dispensed with. Advantageously, the second and / or third organic refrigerant in the present invention comprises a halogenated or non-halogenated alkane or alkene having at most four carbon atoms, which is suitable for particularly low temperatures.

In the context of the present invention, the organic refrigerant (s) (the first, the second and / or the third organic refrigerant) are warmed in the first operating mode to the same ("upper") temperature level from which they are cooled in the second operating mode , Conversely, in the second mode of operation, they are or are cooled to the same ("lower") temperature level from which they are warmed in the first mode of operation. Due to unavoidable losses, the term "same temperature level" is understood to mean not only exactly the same temperature, but a temperature band of a width of up to, for example, 20 ° C. Of course, the aim is to achieve the lowest possible temperature difference between the two operating modes. By the heat exchange units used, the heat exchange diagrams of the heat exchange system of the gas treatment unit can be made particularly favorable.

Particularly advantageous is a method in which the first organic refrigerant, i. the refrigerant of the second heat exchange unit, in the first operating mode from a lower temperature level at -100 to -30 ° C, in particular at -60 to -40 ° C, to an upper temperature level at 0 to 80 ° C, in particular at 20 to 50 ° C, heated, and is cooled in the second operating mode from the upper temperature level to the lower temperature level.

Also advantageous is a method wherein the second organic refrigerant, i. one of the refrigerants of the third heat exchange unit, in the first operating mode from a first temperature level at -200 to -140 ° C., in particular at -196 to 150 ° C., to a second temperature level at -100 to -30 ° C., in particular at 60 to -40 ° C, heated, and is cooled in the second operating mode from the second temperature level to the first temperature level.

In this embodiment of the method according to the invention is advantageously the third organic refrigerant, which is also a refrigerant of the third heat exchange unit in the first mode of operation from a third temperature level at -200 to -140 ° C, in particular at -196 to -150 ° C. a fourth temperature level at -140 to -60 ° C, in particular at -100 to -60 ° C, heated and cooled in the second operating mode from the fourth temperature level to the third temperature level.

Here, in the first operating mode, advantageously, the second organic refrigerant on the first and third organic refrigerants is supplied at the third temperature level of the third heat exchange unit, and the second organic refrigerant on the second and the third organic refrigerants are taken out at the fourth temperature level thereof. Accordingly, in the second operation mode, the second organic refrigerant on the second and third organic refrigerants at the fourth temperature level is advantageously supplied to the third heat exchange unit, and the second organic refrigerant on the first and third organic refrigerants is taken at the third temperature level thereof.

A corresponding combination system is advantageously designed for carrying out a corresponding method. The second organic refrigerant is advantageously completely, the third performed only in a section through the third heat exchange unit. As also with reference to the attached FIG. 5 explained, this results in particularly favorable temperature gradients in the first heat exchange unit.

The organic refrigerants used differ in their chemical composition, in particular in their boiling point. They must be selected so that they are fluid throughout their workspace. In addition to the already mentioned organic refrigerants are explicitly in the table on page 5 of WO 2014/026738 A2 listed substances for use in the invention as a first, second and / or third organic refrigerant in question.

Organic refrigerants can also be the following refrigerants according to the common DuPont nomenclature (see DIN 8960 section 6.3.2), namely halogenated and non-halogenated hydrocarbons with one carbon atom such as R-10, R-11, R-12, R-12B1 , R-12B2, R-13, R-13B1, R-14, R-20, R-21, R-22, R-22B1, R-23, R-30, R-31, R-32, R -40, R-41 and R-50, having 2 carbon atoms, such as R-110, R-111, R-112, R-112a, R-113, R-113a, R-114, R-114a, R-115 , R-116, R-120, R-122, R-123, R-123a, R-123b, R-124, R-124a, R-125, R-131, R-132, R-133a, R -134, R-134a, R-141, R-141b, R-142, R-142b, R-143, R-143a, R-150, R-150a, R-151, R-152a, R-160 and R-170, having two carbon atoms and C double bond, such as R-1112a, R-1113, R-1114, R-1120, R-1130, R-1132a, R-1140, R-1141 and R-1150, having 3 carbon atoms, such as R-211, R-212, R-213, R-214, R-215, R-216, R- 216ca, R-217, R-217ba, R-218, R-221, R-222, R-222c, R-223, R-223ca, R-223cb, R-224, R-224ca, R-224cb, R-224cc, R-225, R-225aa, R-225ba, R-225bb, R-225ca, R-225cb, R-225cc, R-225da, R-225ea, R-225eb, R-226, R- 226ba, R-226ca, R-226cb, R-226da, R-226ea, R-227ea, R-236fa, R-245cb, R-245fa, R-261, R-261ba, R-262, R-262ca, R-262fa, R-262fb, R-263, R-271, R-271b, R-271d, R-271fb, R-272, R-281, and R-290, having 3 carbon atoms and C double bond, such as R- 1216, R, R-1225ye, R-1225zc, R-1234ye (E), R-1234ye (Z), R-1234yf, R-1234ze, R-1243zf and R-1270, fluorinated hydrocarbons having 4 or more carbon atoms, such as R-C316, R-C317 and R-C318, chlorine- and fluorine-free hydrocarbons having 4 or more carbon atoms, such as R-number, R-600, R-600a, R-601, R-601a, R-601b, R- 610, R-611, R-630 and R-631, zeotropic mixtures of corresponding refrigerants such as R-401A, R-401B, R-401C, R-402A, R-402B, R-403A, R-403B, R-404A, R-405A, R-406A, R-407A, R-407B, R-407C, R-407D, R-408A, R-409A, R- 409B, R-410A, R-410B, R-411A, R-411B, R-412A, R-413A, R-417A, R-422A, R-422B, R-422C and R-422D, as well as azeotropic mixtures of corresponding refrigerants such as R-500, R-501, R-502, R-503, R-504, R-505, R-506, R-507 [A], R-508 [A], R-508B and R -509 [A].

In the context of the present invention, advantageously, a fourth heat exchange unit can be used, by means of which the heat transfer fluid is partially cooled in the first operating mode, and which is operated with further compressed feed gas, which is depressurized. In this way, in particular in the first operating mode additional cold to cover cold losses can be generated, as it is also known in air separation plants, there in the form of a so-called turbine flow.

The present invention also extends to a combination energy storage and recovery system having all the means to make it suitable for carrying out a previously discussed method. For features and advantages of a corresponding combination system is expressly made to the corresponding claim and the above explanations.

In particular, in a corresponding combination plant, a third heat exchange unit is designed such that in the first operating mode it has the second organic refrigerant on the first and the third organic refrigerant supplied to the third temperature level and the second organic refrigerant can be removed on the second and the third organic refrigerant at the fourth temperature level and further supplied in the second operating mode, the second organic refrigerant on the second and the third organic refrigerant at the fourth temperature level and second organic refrigerant can be removed on the first and the third organic refrigerant at the third temperature level.

The invention and preferred embodiments of the invention will be explained in more detail with reference to the accompanying drawings.

Brief description of the drawings

• Figure 1A FIG. 2 illustrates a combination plant according to an embodiment of the invention in a first operating mode in the form of a process flow diagram, FIG.
• FIG. 1B illustrates the combination plant according to Figure 1A in a second mode of operation in the form of a process flow diagram.
• FIG. 2A illustrates components of a heat exchange system according to an embodiment of the invention in the first mode of operation in the form of a process flow diagram.
• FIG. 2B illustrates the components according to FIG. 2A in the second mode of operation in the form of a process flow diagram.
• FIG. 3A illustrates components of a heat exchange system according to an embodiment of the invention in the first mode of operation in the form of a process flow diagram.
• FIG. 3B illustrates the components according to FIG. 3A in the second mode of operation in the form of a process flow diagram.
• FIG. 4A 1 illustrates a combination plant according to another embodiment of the invention in the first operating mode in the form of a process flow diagram.
• FIG. 4B illustrates the combination plant according to FIG. 4A in the second mode of operation in the form of a process flow diagram.
• FIG. 5 illustrates according to an embodiment of the invention achievable heat exchange profiles in a diagram.

In the figures, corresponding elements and fluid streams are illustrated with identical reference numerals. In all figures, systems or plant components are illustrated in different operating modes, which in addition to the illustrated elements have additional elements such as valves and valves. Corresponding valves and fittings are not illustrated for the sake of clarity, for illustration, however, blocked by valves and valves fluid paths or correspondingly inactivated currents are shown crossed. Mainly or exclusively gaseous streams are illustrated in the form of unfilled (white) arrow triangles, predominantly or exclusively liquid streams in the form of filled (black) arrow triangles. The invention will be illustrated with reference to an air treatment unit as a gas treatment unit.

Detailed description of the drawings

Figure 1A 1 illustrates a combination plant according to an embodiment of the invention in a first operating mode in the form of a process flow diagram. The combination system, which in FIG. 1B in a second mode of operation is indicated generally at 100 and includes an air handling unit 110 and a power generation unit 120.

In the air treatment unit 110, in the illustrated example, feed air in the form of a stream a is sucked in via a filter 1 by means of a main air compressor 2 with intercoolers not specifically designated. The feed air of the stream a is compressed in the main air compressor 2, for example to a pressure of about 5 to 7 bar. One correspondingly compressed stream, now denoted by b, is fed to a cooling unit 3 operated with cooling water streams which are not separately designated, where the previously supplied heat of compression is withdrawn from the stream b. A correspondingly cooled stream, now denoted by c, is freed from the predominant part of the water and carbon dioxide contained in an adsorptive cleaning unit 4, which may comprise, for example, a pair of molecular sieve filled, not separately designated adsorber containers. A stream purified in this way, now denoted d, is fed to a secondary compressor 5 and subsequently recompressed to a pressure of, for example, about 9 bar. A correspondingly recompressed stream, now denoted by e, is fed into a heat exchange system of the air treatment unit, which is designated here in its entirety by 10.

In the heat exchange system 10 of the air treatment unit 110, the compressed feed air of the stream e in a first heat exchange unit 11 is cooled against a flow f of a heat transfer fluid to obtain a corresponding cooled flow g. The current f and the current e are in each case at pressure levels which are referred to above and below as "first" pressure levels. The current f is brought by means of a subsequently explained pump 15 to its "first" pressure level, the current g by means of the described compression. Values for the "first" pressure levels and possible deviations between them have already been explained. The cooled stream g is relaxed in the example shown in a generator turbine 12 and possibly one of these downstream, not separately designated expansion valve. The correspondingly relaxed stream g is transferred to a separator tank 13, in the bottom of which a liquid fraction and at the top of which a gaseous fraction is formed. The liquid fraction from the bottom of the separator tank 13 is transferred in the form of the flow h into a storage system 20 in which it is stored in the first operating mode. The storage system 20 may, in addition to the stream h, as already mentioned above, also be charged with further liquid cryogenic streams. The storage system 20 is removed in the first mode of operation in the example shown no fluid.

The gaseous fraction from the top of the separator tank 13 is withdrawn in the form of the stream i and heated in a further heat exchange unit 14, here referred to as the fourth heat exchange unit 14 in comparison with the second and third heat exchange units 16 and 18 explained below. In the fourth heat exchange unit In this case, cooling of the current i can be transferred to a current k, which likewise comprises a heat transfer fluid and is combined with a further corresponding current I to the already mentioned current f of the heat transfer fluid. By the current f and the currents k and I, two partial circuits of a heat transfer fluid are formed, which are driven by the pump 15 and in this, as well as in the first heat exchange unit 11, are linked together. It is, as already emphasized, that in the mentioned subcircuits no cold-performing relaxation of a corresponding heat transfer fluid takes place, this essentially serves only for the transfer of heat, but not for their production.

The current I is before the union of the stream f and the feed into the heat exchanger 11 by means of the pump 15, and after the distribution of the current f into the currents k and I downstream of the heat exchange unit 11, ie at its warm end, through the already mentioned two further heat exchange units 16 and 18, namely the second heat exchange unit 16 and the third heat exchange unit 18, performed in which the current I is cooled by means of organic refrigerant, which are respectively provided by refrigerant units 17 and 19. Details of the heat exchange units 16 and 18 and the refrigerant units 17 and 19 are described with reference to FIGS FIGS. 2A and 2B or 3A and 3B explained.

To provide further cooling, a partial flow m can be branched off from the compressed feed air of the flow d, cooled in the heat exchanger 14 to an intermediate temperature, cooled in a non-separately designated generator turbine and returned through the heat exchanger 14. A correspondingly recirculated stream can be used, for example, in the form of the stream n as regeneration gas in the adsorptive purification unit 4. The current i can, for example, be combined with the current d upstream of the secondary compressor 5.

Other components of the air treatment unit 110 and components of the power generation unit 120, which in the in Figure 1A is not in operation, will be described below with reference to the FIG. 1B explaining in which the second operating mode is illustrated.

In FIG. 1B is the combination plant 100, which is already in Figure 1A illustrated in the first mode of operation, shown in the second mode of operation. In the in FIG. 1B In the illustrated second mode of operation, the flow e is not provided, the main compressor 2 and the booster 5 may be out of operation or operated in a standby mode. The adsorptive cleaning device 4 can during the in FIG. 1B illustrated second operating mode, for example, be regenerated. Accordingly, no cooled, compressed feed air is released in the generator turbine 12 and no fluid is transferred into the storage system 20. Also in the first operating mode according to Figure 1A Refrigerant circuit realized by the flow k through the fourth heat exchange unit 14 is typically not in operation here.

Instead, in the second mode of operation according to FIG. 1B the storage system 20 fluid in the form of the current o, so a storage fluid, taken and provided in the form of a cryogenic process fluid. In the first operating mode according to Figure 1A In the storage system, a cryogenic air liquefaction product was fed from the sump of the separator tank 13. The current o is heated and evaporated in the second operating mode in the heat exchanger 11. The current o transmits its cold to a current p, from the same heat transfer fluid of the currents f, k and I of the first operating mode according to Figure 1A is formed here, but here for the better distinctness is called divergent. The currents o and p are respectively at pressure levels referred to above and below as "second" pressure levels. The current o is brought by means of a not separately designated pump to its "second" pressure level, the current p has this pressure level after passing through the second heat exchange unit 16 and the third heat exchange unit 18 by means of the illustrated pump 15. Values for the "second" pressure levels and possible deviations between these have already been explained. One in the second operating mode according to FIG. 1B The refrigerant circuit realized by the flow p also includes the already mentioned second and third heat exchange units 16 and 18 or the associated refrigerant units 17 and 19, which are described in the following FIGS. 2A and 2B or 3A and 3B are explained.

By heating and evaporating the stream o, ie the cryogenic process liquid, a gaseous or supercritical pressurized fluid in the form of the stream q is provided, which is supplied to the energy generating unit 120. In the power generation unit 120, the power q, for example, performing work and while releasing electrical energy in a generator turbine 121. The stream q may previously be passed through a heat exchanger 122 and heated therein by means of an exhaust gas stream of a combustion chamber 123 or a heat engine in which a fuel is burned with air or another oxygen-containing gas.

In FIG. 2A is the second heat exchange unit 16 with the associated refrigerant unit 17 of the system 100, as shown in the Figures 1A and 1B is shown in the first and second modes of operation illustrated in the first mode of operation. By the second heat exchange unit 16, as already in Figure 1A illustrates the current I of the heat transfer fluid out. In countercurrent to the current I, a gaseous stream r is passed, which flows out of a first refrigerant reservoir 171, is cooled in the second heat exchange unit 16 and then flows into a second refrigerant reservoir 172. The gaseous stream r is non-condensing gas, for example nitrogen, at the temperatures described above. The flow r is provided by increasingly displacing corresponding gas from the first refrigerant reservoir 171. For this purpose, an organic refrigerant is taken from the second refrigerant storage 172 by means of a pump 173 in liquid form, passed through the heat exchanger 16 and fed into the first refrigerant storage 171. A corresponding stream of the organic refrigerant is designated s.

In FIG. 2B is the second heat exchange unit 16 with the associated refrigerant unit 17, which in FIG. 2A shown in the first mode of operation, shown in the second mode of operation. As already with reference to the FIG. 1 B, a current p of the heat transfer fluid is passed through the second heat exchange unit 16 here. The guidance of an organic refrigerant or a superimposed gas in the storage containers 171 and 172 takes place with respect to the first operating mode, which in FIG. 2A is shown in the second operating mode, which in FIG. 2B is shown, in the opposite direction. Corresponding currents are therefore illustrated by r 'and s'.

In the FIGS. 3A and 3B is the third heat exchange unit 18 with the associated refrigerant unit 19 of the system 100, as shown in the Figures 1A and 1B in the first and second modes of operation, in the first and second modes of operation illustrated. There are two organic refrigerant streams, for example, include propane as a refrigerant used. The basic operation of the refrigerant unit 19 has already been described with reference to FIGS FIGS. 2A and 2B explained. In the first mode of operation, as in FIG. 3A is illustrated, a first refrigerant flow t is completely guided through the third heat exchange unit 18, a second refrigerant flow u only through a portion of this third heat exchange unit 18. Corresponding refrigerant accumulators and pumps are designated here by 191 to 196. Again, those in the second mode of operation, which are in FIG. 2B is illustrated, reversely guided refrigerant flows denoted by t 'and u'. The gaseous fluid streams also used in the two FIGS. 2A and 2B denoted by v and w and v 'and w'. If refrigerant is exchanged between the two refrigerant circuits in the two operating modes, as illustrated by x and x '.

FIG. 4A FIG. 2 illustrates a combination plant according to a further embodiment of the invention in the first operating mode in the form of a process flow diagram, wherein only the heat exchange system 10 is illustrated here, its integration into the combination plant essentially the same as in the combination plant 100 according to FIGS Figures 1A and 1B can be. Again is in FIG. 4A the first and in FIG. 4B the second operating mode of the combination system illustrated.

The recompressed flow e is determined according to FIG. 4A before or in the heat exchange system 10 divided into two partial streams and cooled in the first heat exchange unit 11 and the fourth heat exchange unit 14. In the first operating mode the in FIG. 4A shown combination system, however, only a flow f of a heat transfer fluid is performed by the first heat exchange unit 11, a current k, as in Figure 1A is shown, does not exist. The current I corresponds according to FIG. 4A the current f. The cooled current g is formed by combining the partial currents of the current e. The current g is, as already to Figure 1A explained, liquefied and stored. The currents i and m have already been explained above.

In FIG. 4B is the combination system that is in FIG. 4A illustrated in the first mode of operation, shown in the second mode of operation. Not explained here Details be on FIG. 1B directed. In the in FIG. 4B illustrated second operating mode, the fourth heat exchange unit 14 is not flowed through by a partial flow of the liquefied air product or the storage liquid formed therefrom. Only by the first heat exchange unit 11, as already to FIG. 2B explained, a current 1 led.

For the "first" pressure levels of the flows f and g and the "second" pressure levels of the flows o and p in the FIGS. 4A and 4B the multiple explained applies.

In FIG. 5 a heat exchange diagram achievable in accordance with an embodiment of the invention is illustrated and indicated generally at 500. In the diagram, an exchanged heat in kW is plotted on the abscissa and a temperature in K on the ordinate.

501 is a heat exchange profile for the compressed feed air, 502 is a heat exchange profile for the storage liquid formed from the liquefied air product, and 503 and 504 illustrates heat exchange profiles for the heat transfer fluid. It can be seen from the heat exchange diagram 500 that the invention enables a particularly narrow guide of the heat exchange profiles 501 and 503 or 503 and 504.

Claims (15)

A method of storing and recovering energy using a combination plant (100) comprising a gas treatment unit (110) and a power generation unit (120), wherein in a first mode of operation of compressed feed gas cooled in a heat exchange system (10) of the gas treatment unit (110), producing a cryogenic gas liquefaction product, and providing a storage liquid using the gas liquefaction product, in a second mode of operation using the storage liquid, a cryogenic process liquid is provided which is heated in the heat exchange system (10) to obtain a pressurized fluid which is work-expanded in the energy-generating unit (120), the compressed feed gas in a first heat exchange unit (11) of the heat exchange system (10) is cooled countercurrently to a heat transfer fluid in the first operating mode and the process liquid in the first heat exchange unit (11) is heated in countercurrent to the heat transfer fluid in the second operating mode, the heat transfer fluid is cooled in the first operating mode and heated in the second operating mode at least in part by means of at least two further heat exchange units (16, 18) of the heat exchange system (10) which are operated at different temperature levels and in each case with at least one organic refrigerant, the directions in which the heat transfer fluid and the feed gas are passed through the first heat exchange unit (11) in the first operating mode are opposite to the directions in which the heat transfer fluid and the process liquid are passed through in the second operating mode, and in the first operating mode, the heat transfer fluid and the compressed feed gas in each case at first pressure levels and the heat transfer fluid and the process fluid in the second operating mode are respectively passed through the first heat exchange unit at second pressure levels, wherein the first pressure levels are at least 5 bar above the second pressure level lie. The method of claim 1, wherein as the heat transfer fluid a fluid is used that is free of or low in oxidizing and combustible components. A method according to claim 1 or 2, wherein as the heat transfer fluid a predominantly nitrogen, neon, helium and / or argon containing fluid is used. Method according to one of the preceding claims, wherein an air treatment unit (110) is used as a gas treatment unit (110) and in the first operating mode of compressed feed air as compressed feed gas, which is cooled in the heat exchange system (10) of the air treatment unit (110), a cryogenic Air liquefaction product is produced as a gas liquefaction product. Method according to one of the preceding claims, in which the first pressure levels of the first operating mode are 50 to 120 bar and / or the second pressure levels of the second operating mode are 40 to 60 bar. Method according to one of the preceding claims, wherein the at least two further heat exchange units (16, 18) comprise a second heat exchange unit (16) which is operated with a first organic refrigerant, which is transferred between two storage containers (171, 172). A method according to claim 6, wherein as the first organic refrigerant, a fluid containing a halogenated or non-halogenated alkane or alkene, at least one alcohol and / or at least one aromatic is used. Method according to one of claims 6 or 7, wherein the at least two further heat exchange units (16, 18) comprise a third heat exchange unit (18), which is operated with a second organic refrigerant, which is transferred between two storage containers (191, 192), and further operated with a third organic refrigerant transferred between two storage tanks (194, 195). The method of claim 8, wherein the second organic refrigerant in the first mode of operation from a first temperature level at -200 to -140 ° C, in particular at -196 to 150 ° C, to a second temperature level at -100 to -30 ° C. , in particular at -60 to -40 ° C, heated, and is cooled in the second operating mode from the second temperature level to the first temperature level. The method of claim 9, wherein the third organic refrigerant in the first mode of operation from a third temperature level at -200 to -140 ° C, in particular at -196 to 150 ° C, to a fourth temperature level at -140 to -60 ° C. , in particular at -100 to -60 ° C, heated and cooled in the second operating mode from the fourth temperature level to the third temperature level. The method of claim 10, wherein in the first mode of operation, the second organic refrigerant on the first and third organic refrigerants at the third temperature level of the second heat exchange unit (16) supplied and the second organic refrigerant on the second and the third organic refrigerant on the fourth Temperature level is taken from this and / or in the second operating mode in the second organic refrigerant on the second and the third organic refrigerant at the fourth temperature level of the second heat exchange unit (16) supplied and the second organic refrigerant on the first and the third organic refrigerant on the third temperature level is taken from this. Method according to one of claims 8 to 11, wherein as the second and the third organic refrigerant, an identical fluid is used. Method according to one of claims 8 to 12, wherein the second and / or third organic refrigerant, a fluid is used, which contains a halogenated or non-halogenated alkane or alkene having at most four carbon atoms. A method according to any one of the preceding claims, wherein a fourth heat exchange unit (14) is used by which the heat transfer fluid is partially cooled in the first mode of operation and which is operated with further compressed feed gas which is depressurized. A combination energy storage and recovery system (100) comprising a gas treatment unit (110) and a power generation unit (120), the combination installation (100) having means adapted to in a first mode of operation of compressed feed gas cooled in a heat exchange system (10) of the gas treatment unit (110) to produce a cryogenic gas liquefaction product and to provide a storage liquid using the gas liquefaction product, in a second mode of operation using the storage liquid, to provide a cryogenic process liquid, to heat it in the heat exchange system (10) to obtain a pressurized fluid, and to relax the pressurized fluid in the power generation unit (120), to cool the compressed feed gas in a first heat exchange unit (11) of the heat exchange system (10) in countercurrent to a heat transfer fluid in the first operating mode and to heat the process liquid in the first heat exchange unit (11) in countercurrent to the heat transfer fluid in the second operating mode, - The heat transfer fluid at least partially by means of at least two further heat exchange units (16,18) of the heat exchange system (10), which are operated at different temperatures and each with at least one organic refrigerant to cool in the first mode of operation and to heat in the second mode of operation the directions in which the heat transfer fluid and the feed gas are guided in the first operating mode through the first heat exchange unit (11), opposite to the directions in which the heat transfer fluid and the process liquid are passed through in the second operating mode, and in the first mode of operation, each of the heat transfer fluid and the compressed feed gas at first pressure levels and the heat transfer fluid and the process liquid in the second operating mode at second pressure levels through the first heat exchange unit (11), the first pressure levels being at least 5 bar above the second pressure level lie.

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