WO2013182907A2

WO2013182907A2 - Process and device for regasifying low-temperature liquefied gas

Info

Publication number: WO2013182907A2
Application number: PCT/IB2013/001711
Authority: WO
Inventors: Werner Hermeling
Original assignee: Werner Hermeling
Priority date: 2012-06-05
Filing date: 2013-08-05
Publication date: 2013-12-12
Also published as: EP2906350A2; WO2013182907A3

Abstract

In a process for regasifying low-temperature liquefied gas in which some of the low-temperature liquefied gas situated in a tank (1) is brought from the tank (1) into a metering reservoir (2), the metering reservoir (2) is separated from the tank (1), and a metered amount of the low-temperature liquefied gas is then fed to an evaporator (20), whereupon the vaporized amount of gas is charged into a high-pressure gas reservoir (24) or is fed into a pipe network, whereupon the evaporator (20) is separated from the metering reservoir (2), the pressure in the metering reservoir (2) is lowered and the metering reservoir (2) is again charged with liquefied gas from the tank (1), the pressure in the metering reservoir (2) is lowered in that the gas situated in the metering reservoir (2) is conducted through a heat exchanger (14) in which the gas is cooled and/or partially condensed, wherein the condensate possibly formed in the heat exchanger and the cooled gas at the remaining gas pressure are guided into the tank (1), and the cooled gas is condensed in the part of the tank (1) containing the liquefied gas.

Description

Method and device for regasifying cryogenic liquefied gas

The invention relates to a process for the regasification of cryogenic liquefied. Gas, in which a part of the located in an isolated tank cryogenic liquefied gas is spent by the tank in an insulated Dosierspeicher, the Dosierspeicher is separated from the tank and a metered amount of cryogenic liquefied gas is then fed by activation of an evaporator circuit an evaporator, whereupon at the same time or subsequently the vaporized gas is filled into a high-pressure gas storage or fed into a mains network, whereupon the evaporator is separated from the metering, the pressure degraded in Dosierspeicher and the dispenser is filled again with liquefied gas from the tank.

The invention further relates to a device for regasification of cryogenic liquefied gas comprising an insulated tank, an insulated dosing tank connected to the tank via at least one connecting line, an evaporator connected to the dosing tank via at least one connecting line and a return line and one connected to the evaporator High-pressure accumulator or connected to the evaporator line of a pipeline network, wherein the at least one connecting line between the tank and the Dosierspeicher having at least one connecting line and the return line between the Dosierspeicher and the evaporator each have a shut-off valve.

A method and a device of the type mentioned above, with which a piston-free compression of gases is possible, are known from WO 2011/009149 AI. In the method described in WO 2011/009149 AI are two or more Strands connected in parallel, being pressed with the pressure of one strand of the dosing memory for the filling of the other strand, especially the evaporator, empty. The liquid enters the dosing tank downstream air evaporator, ie the liquid must be pressed against the pressure located in the evaporator in this. The pressure in the dosing tank must be reduced before refilling the dosing tank with liquefied gas by releasing it through a throttle into the gas space of the tank. In this case, a gas phase and a liquid phase accumulates and there is a pressure equalization between the dispenser and the tank. As soon as the gas pressure in the tank reaches an inadmissibly high value, the gas from the gas space of the tank must be blown off from time to time. Furthermore, in this procedure, it is accepted that very high pressure peaks occur for filling the one strand through the other.

The present invention aims to avoid the disadvantages of the prior art.

To achieve this object, the method of the type mentioned ge ^¬ called is essentially carried out in such a way that the pressure in the dispenser is reduced by the fact that the gas contained in the dispenser is fed through a heat exchanger in which cooled the gas and / or partially condensed is wherein, preferably, the condensate formed in the heat exchanger and the cooled gas having the remaining gas pressure are forced into the tank, and the cooled gas having the remaining gas pressure is passed into the tank, and the cooled gas is condensed in the part of the tank containing the liquefied gas. The gas located in the metering memory is thus cooled in the heat exchanger and, if possible, at least partially condensed, whereby a part of the energy of the pressurized gas is first discharged outside the tank, whereupon the remaining part of the energy can be delivered to the liquid in the tank and released to tank pressure. For this purpose, the gas pressure in the heat exchanger is condensed in the liquid phase of the tank. This eliminates the need to blow off the gas in the gas space of the tank from time to time and thereby lose gas. The heat exchanger is located outside the tank, the condenser inside the tank.

The product leaving the condenser mixes in the outlet area of the condenser with the liquefied gas in the tank. In the condenser, it inevitably comes to the condensation of the supplied gas from the heat exchanger, wherein the cooling medium is the liquid of the tank.

Preferably, it is provided that the heat exchanger liquid gas is supplied from the Dosierspeicher as a cooling medium and the heated in the heat exchanger or evaporated cooling medium is supplied to the evaporator for the purpose of further energy absorption.

Preferably, it is further provided that the heat exchanger has at least one gas-carrying pipe, in which the cooling of the gas takes place, so that a condensation is possible. The condenser preferably comprises at least one line extending in the interior of the tank, in particular a cooling coil, through which gas and condensate flow out of the heat exchanger.

A particularly economical process management is made possible when the liquefied gas is preferably filled under the geodetic pressure in the dosing. Alternatively, you can the required pressure difference can also be applied or supported by a circulating pump. The filling of the metering reservoir advantageously comprises the production of a pressure equalization between the tank and the metering reservoir.

Furthermore, it is advantageous to fill the heat exchanger before filling the evaporator and to empty the excess liquid, which can not be absorbed by the heat exchanger, in the evaporator. The aim is to fill the heat exchanger with - to be evaporated cooling medium, so that this can cool the gas in the dispenser before relaxation in the subsequent process of pressure equalization. If the dosing tank is now connected to the evaporator, the product flow is conducted into the heat exchanger by the geodetic pressure, which is "flooded", the overflowing product passes into the evaporator and is completely transferred to the gas phase, which evaporates through the heat exchange in the heat exchanger Product is replaced by product flowing out of the dosing tank and the excess product flows to the evaporator for evaporation.

Thereafter, for the purpose of pressure equalization between dispenser and tank the dispenser is separated from the evaporator and its pressure is released into the tank. For relaxation, the gas of Dosierspeichers is passed through the heat exchanger and the condenser in the tank. There is a pressure equalization and the dispenser can be filled again.

In order to comply with the cryogenic conditions in the tank, the procedure is preferably such that the pressure in the tank is kept below the permissible operating pressure of the tank, in particular less than 15 bar, so that it is ensured that the tank can not blow off. The cooling and condensation of the supplied from the heat exchanger product in the tank usually has a slight warming of the liquid phase in the tank result, so that it can lead to an increase in pressure in the tank. In order to avoid a blow-off of gas from the gas space of the tank as a result of this pressure increase, the procedure is preferably such that filling of the dosing tank takes place via one of at least two connecting lines opening out at different levels within the tank, the removal of the cryogenic liquefied gas the tank is via the highest-opening connecting line, which allows the falling level of the tank respectively. This creates the possibility of removing the "warmer" liquid from the tank and feeding it to the dosing tank so that the heat introduced into the liquid phase of the tank by the condensation is immediately removed again with the withdrawn amount of the liquid phase.

In order to advantageously enable the use of energy coming from the environment for the regasification of the cryogenic liquefied gas, a preferred procedure provides that the evaporation takes place with the enthalpy of the air.

To solve the object underlying the invention is provided according to a further aspect of the invention in a device of the type mentioned above, that a portion of the dispenser connecting the dispenser with the evaporator connecting line forms a coolant line of an insulated heat exchanger, the coming of the Dosierspeicher gas whose cooling and / or partial condensation can be flowed through and which is connected to a capacitor arranged in the tank. The condenser preferably comprises at least one line running in the interior of the tank, in particular a cooling coil, through which gas can flow from the metering tank. The at least one line and its outlet mouth are preferably surrounded by a pipe arranged in the tank. The tube serves to separate the liquid phase heated by the condenser from the remaining liquid phase of the tank. This makes it possible to limit the area of heat input, wherein the spatial separation allows subsequently to deploy the heated portion of the liquid phase targeted from the tank. A preferred development of the device according to the invention provides in this connection that at least two connecting lines connecting the tank to the metering reservoir open into the tank at different heights. In particular, the connecting lines open inside the tube in the tank.

In order to enable filling of the metering reservoir under the geodetic pressure of the tank, it is preferably provided that the liquid feed is arranged deeper into the metering reservoir than the liquid outlet from the tank. It is also possible to arrange the heat exchanger and the evaporator inlet lower than the dispenser. The feed can also be done by a supporting circulation pump.

Preferably, the Dosierspeicher is connected via a gas return line to the gas space of the tank, whereby a pressure equalization between the Dosierspeicher and the tank is made possible directly.

To the heat input into the cryogenic part of the system, which includes the tank, the dosing tank, the heat exchanger and the lines connecting the tank and the dosing, too minimize, provides a preferred development that the tank, the dosing, the heat exchanger and the tank connecting the dosing memory lines are thermally insulated. On the other hand, the evaporator is preferably not thermally insulated so that the ambient entropy can be used to vaporize the gas.

The non-heat-insulated version of the evaporator has the disadvantage that the evaporator ices up, which isolates the evaporator, i. that the heat supply to the evaporator is reduced from the outside. In this regard, this can be remedied that the evaporator is increased. But this is only a time-delaying measure. Continuously, the next section of the evaporator will freeze, so that the only way is to prevent this icing by switching to another evaporator, which in turn significantly increases the cost of the plant. In the context of the invention, icing is preferably avoided by virtue of the evaporator having on its outside a coating which avoids this icing, e.g. a nanotechnology-based molecular structure.

However, the surface of the evaporator can also be kept free from mechanical or chemical treatment steps of ice or other solidification products, wherein the mechanical variant is, for example, a scraping off and the chemical variant is the use of a thawing agent, so that the evaporator is in continuous operation can work.

If, in the context of the invention, reference is made to cryogenic liquefied gases, liquefied gases (analogous or similar to lime), for example, are obtained by cooling and compression. Process) to understand that remain at atmospheric pressure due to the enthalpy of vaporization with appropriate thermal insulation cold and liquid (eg, liquid oxygen and liquid nitrogen). The boiling point of such gases is usually below -160 ° C at atmospheric pressure. Another example is the so-called liquefied natural gas (LNG), which is liquefied natural gas gas by cooling to -164 to -161 ° C (109 K to 112 K) and about one-600th of the volume of natural gas having.

Refrigerated liquefied gases are stored in heat-insulated tanks, so-called cryogenic containers. The reaching within the scope of the invention used tank as well as the dispenser and the heat exchanger are designed for example as a double-walled container, the space between the outer wall and the inner wall is evacuated. The inside of the inner wall is preferably provided with a reflective coating. It is also possible to place the dispenser, the valves and the pipes in an insulated container, so that evaporation is excluded or severely limited.

In the context of the invention, a metered storage tank is preferably to be understood as meaning a heat-insulated storage tank whose volume is significantly lower than that of the tank. In particular, the volume of the Dosierspeichers corresponds to less than half, preferably less than a quarter of the volume of the tank.

The heat exchanger absorbs the part of the liquid that is required for cooling or condensation of the product, depending on the process design. In the system according to the invention two circuits are connected in series, so that a line is built. In the first cycle of this line, the dosing circuit, the product is stored at a relatively low pressure, for example 15 bar, in a tank. The amount of gas to be evaporated is portioned into the dispenser. The metering reservoir is preferably filled by the geodetic pressure. For this purpose, a pressure equalization between tank and dispenser can be made. This is done for example via a gas return line. However, the prerequisite is that the pressures in the tank and in the dosing tank are such that the inflow from the tank into the dosing tank is possible - the pressures must be the same in the respective gas phase. If this is not the case - for example, the pressure in the dispenser is always higher after the start of the process than in the tank - this pressure must be reduced. The pressure here is predominantly in the supercritical range. The gas returned from the metering reservoir to the tank is passed over the heat exchanger and cooled there. The heat exchanger is integrated with its coolant leading circuit in the evaporator circuit.

The dosing circuit is completely isolated. The evaporation of the gas is only possible according to the unintentionally registered heat. The insulation is to the evaporation of the gas vermei ^¬.

In the second circuit, the evaporator circuit, the product is brought from the metering storage in the evaporator. The product first passes through the heat exchanger and floods it, so that a product exchange or product mixing takes place between existing, ie "warm" product and fresh, ie "cold" product. The evaporator is not insulated and should supply the evaporation and compression energy to the gas. The Energy should be removed from the environment or another free heat source. The supplied energy causes the state change. The evaporator is in the simplest case, a non-insulated, eg cylindrical container.

To bring the product from the dispenser into the evaporator, the dispenser must be separated from the tank and connected to the evaporator. The evaporator inlet is preferably located below the dispenser space. This allows the product to flow through the geodetic pressure into the evaporator. The inflow is made possible by opening or closing valves. This means that the high pressure of the evaporator is everywhere.

The icing of the evaporator has a limited operating life result. Preferably, therefore, the ice layer is removed mechanically in cycles or the preparation of the ice crystals avoided by a suitable coating of the evaporator Oberfiäche.

The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing. In this a block diagram of a Regasifizierungsanlage is shown.

The tank 1, is stored in the cryogenic liquefied gas is designed as an insulated, preferably vacuum-insulated container. The minimum level in the tank 1 is positioned above the maximum level of the dispenser 2 so that the product can flow into the dispenser 2 at the geodetic pressure. The Dosierspeicher 2, which is also designed as an insulated, preferably vacuum-insulated container is connected via a gas space side connected gas return line 3 with the Gas space of the tank 1 connected. In the gas return line 3, the check valve 4 is arranged. The dispenser is further connected via a gas space side connected, equipped with a check valve 29 connecting line 28 with a heat exchanger 14.

On the gas return line 3, which opens into the gas space of the tank 1, the pressure equalization between the tank 1 and the dispenser 2 takes place. On the inlet side, the dispenser 2 is connected to the dispenser 2 via the bottom, connecting lines 5, 6 and 1 of different lengths to the tank 1 connected, the stepped in a capacitor 12 ends. If the tank 1 is filled, the longest connection line 5 is opened via the check valve 8. If the level has dropped, so that no supply can take place via the connecting line 5, the dosing storage 2 is filled via the next longer connecting line 6 or 7 by opening the check valves 9 and 10, respectively. This process continues until the tank 1 is emptied. With this cascading removal, the warmest product is always withdrawn first, so that the pressure increase in the tank 1 is slowed down. For selectively blocking and opening the connecting lines 5, 6 and 7, the check valves 8, 9 and 10 are provided.

The Dosierspeicher 2 is further connected via a line 30 and a check valve 11 with the gas space of the tank 1 connected.

The heat exchanger 14 has a coolant volume 32 and a volume 31 through which the gas to be cooled can flow. On the input side, the volume 31 via the line 28 and the check valve 29 with the gas chamber side of the metering 2 ver ^¬ connected. On the output side, the volume 31 is connected via the line 15 with a cooling coil 13 of a capacitor 12. The Coolant volume 32 of the heat exchanger 14 is connected on the one hand via the check valve 21 to the dispenser 2 and on the other hand to the evaporator 20.

In the tank 1, the condenser 12 is positioned, in the interior of which the cooling coil 13 is located, which is connected via a line 15 with the interposition of the heat exchanger 14 on the head side, ie to the gas space of Dosierspeichers 2. The cooling coil 13 is preferably guided in the tank 1 from top to bottom, so that it is open at the lower end 16, so that there the remaining gas via a mixing nozzle or orifice (not shown) exits. In the embodiment with a mixing nozzle, the suction nozzle ends in the "cold" liquid The condensation of the gas withdrawn from the metering reservoir 2 takes place in the condenser 12. The liquid phase of the tank 1 is used as the coolant, so that the temperature difference necessary for the heat transfer is ensured. The gas flows through the cooling coil 13 and it comes in her for further condensation, in which the heat of condensation is delivered to the surrounding liquid.The cooling coil 13 is surrounded by a tube 17 and thus forms the condenser 12. In the cooling coil, the condensate collects, The remaining gas phase exits via a nozzle and thereby entrains the condensate with it The proportion of gas is reduced by the mixed condensation .. The resulting "warm" liquid remains in the interior of the tube 17. The tube 17 extends up to in the gas space of the tank 1, so that there is no entry of the ext the liquid contained in the tube 17 comes. The bottom-side opening of the tube 17 is surrounded by another sieve-like tube 18, which prevents kal ^¬ te liquid flows from outside the tube 17 directly into the tube 17. The boundary between the dosing circuit described above and the evaporator circuit described below is indicated by the dashed line 19.

The evaporator 20 is connected on the bottom side via a supply line 33 and a check valve 21 and at the outlet via a line 22 and a check valve 23 with the Dosierspeicher 2. The feed line 33 of the evaporator 20 may be laid with a slight slope, wherein the evaporator 20 is placed in parts below the dispenser 2. This favors that the product can flow to the evaporator 20.

The evaporator 20 is followed by the high pressure gas storage 24, which is a finite pressure accumulator, e.g. a pressure vessel store or an infinite pressure store, e.g. a pipeline can be. The goal is to fill both with high-pressure gas. The connecting line between the evaporator 20 and the high pressure accumulator 24 is denoted by 25 and arranged in this line 25 check valve 26.

The method according to the invention is explained below with reference to the following example.

Generally, tank 1 has the lowest pressure, e.g. 10 bar. In Dosierspeicher 2, the pressure between the tank pressure and the evaporator pressure changes. In the evaporator 20, there is always the maximum possible pressure (for example above 200 bar). This is temporarily above the high-pressure accumulator pressure, which is the prerequisite for a memory filling can be done with it.

At the beginning of the process, the tank 1 is connected to the dosing tank 2 via the liquid flow and the gas return 30. For this purpose, one of the valves 8, 9 or 10, the valve 11 and the Valve 27 opened. It adjusts itself to a pressure equalization and the liquid flows to the desired level in the dispenser 2. After the dispenser 2 is filled, the valve 8, 9 and 10 and the valve 27 are closed and the valves 21 and 23 are opened. The product first flows into the volume 32 of the heat exchanger 14 and thereafter, once the volume 32 has been flooded, into the evaporator 20, where the product is preferably supplied with the vaporization and compression energy from the ambient temperature. Upon reaching a pressure which is higher than that of the high-pressure gas reservoir 24, the valve 26 is opened so that pressure equalization takes place between the metering reservoir 2, the evaporator 20 and the high-pressure gas reservoir 24.

It is advantageous here if the pressure rise in the evaporator 20 is detected and from this the maximum expected pressure is calculated. Before reaching the maximum pressure of the high-pressure accumulator 24 is separated from the evaporator 20 by closing the valve 26. The pressure continues to increase, so that in Do ^¬ sierspeicher 2 and in the evaporator 20, the highest pressure prevails. Now, the evaporator 20 is separated from the dosing 2 by closing the valve 23 and the pressure in the downstream high-pressure accumulator by opening valve 26 relaxed. In Do ^¬ sierspeicher 2 now prevails the highest pressure. This pressure ^¬ pad is used to load the evaporator 20 rapidly with product. It also ensures a more even utilization of the evaporator surface.

After filling the high-pressure accumulator 24 prevails in Do ^¬ sierspeicher 2, the pressure of the evaporator 20, which is substantially above the tank pressure. A re-filling is only mög ^¬ exist if a pressure balance between the tank 1 and the Do- - sierspeicher- 2 hergeste11 ... is. For this the must. Pressure in the Sierspeicher 2 are reduced. For this purpose, the valves 21 and 23 are first closed. Thereafter, the gas contained in the dosing tank 2, which is usually in the supercritical state, cooled, so that it reaches the liquid phase area and begins to condense. This is done first in the heat exchanger 14, in the volume 32 is still liquid medium from the previous step, and then in the condenser 12. For this purpose, the valve 29 is opened, the supercritical product initially cools in the heat exchanger 14 and condenses, if necessary, partially condensed then on the walls of the condenser 12, which is surrounded by the "cold" product (max 18 bar) .The process is possible up to the boiling point When a desired temperature is reached the valve 29 is closed and the rest of the gas is opened by opening the valve 4 relaxed in the gas space of the tank 1.

Claims

Claims :

A process for regasifying cryogenic liquefied gas, wherein a portion of the cryogenic liquefied gas in a tank is transferred from the tank to a dosing tank, the dosing tank is separated from the tank and a metered amount of the cryogenic liquefied gas is subsequently fed to an evaporator, whereupon the vaporized gas is filled into a high-pressure gas storage or fed into a mains network, whereupon the evaporator is separated from the dosing tank, the pressure in the dosing tank is reduced and the dosing tank is again filled with liquefied gas from the tank, characterized in that the pressure in the dosing tank ( 2) is degraded in that the gas in the dispenser (2) is passed through a heat exchanger (14), in which the gas is cooled and / or partially condensed, preferably in the heat exchanger (14) optionally formed condensate and the cooled gas with the remaining gas pressure in passed the tank (1) and the cooled gas is condensed in the part of the tank (1) containing the liquefied gas.

2. The method according to claim 1, characterized in that the heat exchanger (14) liquid gas from the Dosierspeicher (2) is supplied as a cooling medium and that in the heat exchanger (14) heated or vaporized cooling medium to the evaporator (20) is supplied.

3. The method according to claim 1 and 2, characterized in that in the heat exchanger (14) cooled gas together with the possibly in the heat exchanger (14) formed condensate through a in the interior of the tank (1) arranged capacitor (12) and at least partially condenses and the condensate itself in an outlet region of the condenser (12) mixed with the liquefied gas in the tank (1).

4. The method of claim 1, 2 or 3, characterized in that the condenser (12) at least one inside the tank (1) extending line (15), in particular a cooling coil (13), which of gas from the heat exchanger ( 14) is flowed through.

5. The method according to any one of claims 1 to 4, characterized in that the liquefied gas is filled under the geodetic pressure in the metering memory (2) and possibly the heat exchanger (14).

6. The method according to any one of claims 1 to 5, characterized in that the filling of the dosing memory (2) comprises the preparation of a pressure equalization between the tank (1) and the dosing memory (2).

Process according to any one of Claims 1 to 6, characterized in that the pressure in the tank (1) is kept below the permissible operating pressure of the tank (1), in particular e.g. less than 15 bar.

8. The method according to any one of claims 1 to 7, characterized in that the filling of the Dosierspeichers (2) via one of at least two at different levels within the tank (1) opening out connecting lines (5, 6, 7), wherein the removal of the cryogenic liquefied gas from the tank (1) via the highest opening connecting line, which allows the falling level of the tank respectively.

9. The method according to any one of claims 1 to 8, characterized in that the evaporation is carried out with the enthalpy of the air or another economically unavailable heat source.

10. An apparatus, in particular for carrying out the method according to one of claims 1 to 9, comprising an insulated tank (1), via at least one connecting line (5,6,7) to the tank (1) connected to insulated dosing memory (2), a via at least one connecting line (33) and a return line (22) with the Dosierspeicher (2) connected to the evaporator (20) and to the evaporator (20) high-pressure accumulator (24) or to the evaporator (20) connected to a line network in which the at least one connecting line (5, 6, 7) between the tank (1) and the metering store (2), the at least one connecting line (33) and the return line (22) between the metering store (2) and the evaporator (20 ) each having a shut-off valve (8,9,10,21,23), characterized in that a portion of the dispenser (2) with the evaporator (20) connecting the connecting line (33) a cooling liquid line (32) of an insulated W is formed rmeübertragers (14) of next of from the dispenser (2) gas can flow through for cooling thereof and / or partial condensation and arranged in a tank (1) capacitor (12).

11. The device according to claim 10, characterized in that the condenser (12) at least one in the interior of the tank (1) extending line, in particular a cooling coil (13) which can be flowed through by the cooled gas from the heat exchanger (14).

12. The device according to claim 11, characterized in that the at least one line and the outlet opening of a tank arranged in the bottom open, first tube (17) are surrounded, wherein the first tube (17) preferably in a second tube (18) ,

13. Device according to one of claims 10 to 12, characterized in that in the tank (1) at least two the tank (1) with the dispenser (2) connecting connecting lines (5, 6, 7) open at different heights.

14. The apparatus according to claim 13, characterized in that the connecting lines (5, 6, 7) within the first tube (17) in the tank (1) open.

15. Device according to one of claims 10 to 14, characterized in that the liquid feed into the dispenser (2) is arranged lower than the liquid outlet from the tank (1).

16. Device according to one of claims 10 to 15, characterized in that the inlet to the heat exchanger (14) allows a passage through the geodetic height from the Dosierspeicher (2).

17. Device according to one of claims 10 to 16, characterized in that the evaporator inlet is arranged lower than the Dosierspeicher (2).

18. Device according to one of claims 10 to 17, characterized in that the dosing memory (2) via a gas return line to the gas space of the tank (1) is connectable.

19. Device according to one of claims 10 to 18, characterized in that the tank (1), the Dosierspeicher (2) and the tank with the Dosierspeicher (2) connecting lines (5, 6, 7) and arranged on these Valves are thermally insulated.

20. Device according to one of claims 10 to 19, characterized in that the evaporator (20) has on its outer side a nano-coating.