Steam accumulator

Abstract

The invention describes a saturated steam storage system for storing water vapor, comprising a container (2) in which water can be stored in its condensed state and as water vapor during operation, a charging device (4) for charging the saturated steam storage system with water vapor, and a discharging device (6) for extracting water vapor from the saturated steam storage system, as well as a method for operating a saturated steam storage system. To improve the discharge capacity without incurring significant disadvantages regarding space requirements, the invention provides a distribution device, in particular comprising at least one nozzle (16), for atomizing water in an upper region of the container (2), or introduces condensed water into an upper region of a container (2).

Description

[0001] The present invention relates to a saturated steam storage system for storing water vapor, comprising a container in which water in the condensed state and as water vapor can be stored during operation, a charging device for charging the saturated steam storage system with water vapor, and a discharging device for removing water vapor from the saturated steam storage system. The invention also relates to a method for operating such a saturated steam storage system.

[0002] In the process industry, steam is required for various applications and is supplied by a steam boiler. Typically, the demand for steam fluctuates depending on the process. To compensate for these fluctuations and, in particular, to ensure a sufficient supply of steam for peak loads, saturated steam storage systems are used. These storage systems extend the capacity of the steam boilers. If the steam boiler cannot adequately meet the steam demand, steam is drawn from the storage system. If the steam demand is less than the amount of steam produced by the boiler, the excess steam can be used to recharge the storage system.

[0003] Saturated steam storage systems are known from the prior art. These systems typically comprise a cylindrical container, which can be configured as either a vertical or horizontal vessel. Steam is stored using the heat of vaporization, usually in condensed form, to allow for a compact design. The vaporous portion of the water is located in the container above the water level formed by the condensed portion. During operation, the container is typically filled with between 50% and 90% condensed water. This percentage varies depending on the state of charge of the saturated steam storage system.

[0004] When charging the saturated steam storage tank, steam is introduced into the tank via a charging device located below the water level. There, the steam condenses and heats the water inside the tank.

[0005] When discharging the saturated steam storage tank, steam is extracted from an upper section of the tank via a discharge device. This process reduces the pressure inside the tank, causing the condensed water to evaporate. The discharge rate and the response speed of the saturated steam storage tank to fluctuations in steam withdrawal are limited by the surface area of ​​the water available for evaporation, i.e., the contact area between the steam and the liquid condensate.

[0006] The water surface area is larger in a horizontal tank compared to a vertical tank. Conversely, the required footprint for a saturated steam storage tank with a horizontal tank is larger than for a vertical tank.

[0007] Against this background, the present invention aims to provide a saturated steam storage system with improved discharge performance without incurring significant disadvantages regarding space requirements. A method for operating such a saturated steam storage system is also to be provided.

[0008] The aforementioned problem is solved according to the invention by a saturated steam storage system for storing water vapor, comprising a container in which water in the condensed state and as water vapor can be stored during operation, a loading device for loading the saturated steam storage system with water vapor, and a discharging device for extracting water vapor from the saturated steam storage system. According to the invention, a distribution device, in particular comprising at least one nozzle, is provided for atomizing water in an upper region of the container.

[0009] The aforementioned problem is further solved according to the invention by a method for operating a saturated steam storage tank according to one of claims 1 to 10, wherein a distribution device, in particular having at least one nozzle, introduces condensed water into an upper region of a container.

[0010] The invention recognizes that introducing atomized water into the upper region of the container effectively increases the contact area available for evaporation between condensed water and water vapor. The upper region of the container is defined by the maximum fill level of the saturated steam storage tank; that is, during operation, the upper region of the container is always above the water level formed by the condensed water. Accordingly, the upper region is always filled with water vapor during operation. By introducing atomized water into the water vapor-filled region, an additional contact area between condensed water and water vapor is created within the container, beyond the existing water level.

[0011] The larger the contact area available for evaporation, the greater the discharge rate; that is, the more water vapor can be extracted from the saturated steam storage system in a comparable time period. Furthermore, the discharge rate can be ramped up more quickly because the reaction rate of the saturated steam storage system is comparatively high. These effects occur without a significantly increased space requirement for the saturated steam storage system.

[0012] Introducing atomized water into the upper part of the container also has a positive effect on loading performance. The increased surface area of ​​the condensed water allows more water vapor to condense in a comparable timeframe, at least when the water vapor is introduced into the container above the water level.

[0013] The following describes various embodiments of the saturated steam storage system and the method, with each embodiment applying independently to the saturated steam storage system and the method. Furthermore, the individual embodiments can be combined with one another as desired.

[0014] In a preferred embodiment of the saturated steam storage tank, a circulation device with a pump and a circulation line is provided, wherein the circulation device is designed such that water condensed during operation from a lower region of the tank can be introduced into the upper region of the tank via the distribution device. The pump conveys condensed water from the lower region of the tank to the upper region of the tank during operation, so that the total amount of water in the tank does not change as a result of this process. In a corresponding embodiment of the invention, the energy from the steam can be introduced into the saturated steam storage tank particularly efficiently.

[0015] The lower range is defined by the minimum condensate level limits that must be maintained during operation. This means the circulation system is designed to ensure that the pump can always remove condensate from the tank during operation.

[0016] Particularly preferably, the lower region is defined as the area extending from the bottom of the container, wherein the lower region has a height of at most 60%, particularly at most 50%, preferably at most 40%, and most preferably at most 30% of the container's height. The lower region defines the minimum fill level of condensed water to be maintained in the container during operation.

[0017] By introducing condensed water into the upper part of the tank, it is possible to utilize water vapor above the water level for condensation. For this reason, the minimum fill level of condensed water required during operation can be reduced compared to conventional saturated steam storage systems, where water vapor must always be introduced below the water level. As a result, with the same tank dimensions, a larger total volume of water vapor can be extracted from the saturated steam storage system, at least if the nozzle geometry is appropriately designed. A saturated steam storage system according to the invention therefore has a larger usable mass range.

[0018] In an advantageous embodiment of the saturated steam storage tank, the upper region is defined as the area extending from the upper ceiling of the tank, wherein the upper region has a height of at least 10%, in particular at least 15%, preferably at least 20%, and most preferably at least 25% of the tank's height. The upper region defines the limits to be observed during operation for the maximum fill level of condensed water in the tank. Such limits have proven advantageous in practice to ensure that, in a saturated steam storage tank design according to the invention, sufficient steam is always present in the upper region of the tank.

[0019] A first lance for introducing steam is particularly preferred in the upper region, with the first lance preferably being arranged below the distribution device. In a saturated steam storage tank according to the invention, it is possible to introduce steam even above the water level. In the upper region, the introduced steam encounters a lower inflow resistance compared to below the water level. To charge the saturated steam storage tank with steam, the pressure in the inlet line connected to the charging device must be higher than the pressure at the outlet of this line. Since the inflow resistance in the upper region is lower than below the water level, more steam can be introduced into the saturated steam storage tank than if the steam were introduced below the water level.Ultimately, a lower pressure differential is required to charge the saturated steam storage tank with steam than with conventional saturated steam storage tanks. Conventional tanks would require a larger pressure difference, such as 5 bar, to introduce steam into the saturated steam storage tank. For example, a saturated steam storage tank with an internal pressure of 20 bar could be charged with an inlet line at 21 bar.

[0020] In an advantageous embodiment of the invention, a second lance for introducing steam is provided in the lower section. Steam can be introduced into the saturated steam storage tank via this lance, either alternatively or in addition to the first lance. It is particularly preferred that both the first lance be located in the upper section and the second lance be located in the lower section of the tank. In this case, the charging capacity can be significantly increased. Alternatively or additionally, a further lance can be provided between the upper and lower sections, which, depending on the charge level of the saturated steam storage tank, can introduce steam above or below the water level formed by the condensed water.

[0021] Preferably, packing elements are arranged on an intermediate shelf in the upper section, with the packing elements positioned below the distribution device. The intermediate shelf and the packing elements arranged on it are located above the first lance. The intermediate shelf is water-permeable, for example, in the form of a grate. The condensed water introduced via the distribution device migrates towards the bottom due to gravity. Condensate collects on the surface of the packing elements. This increases the water surface area available for evaporation and condensation, which in turn has a positive effect on the charging and discharging performance as well as the reaction rate of the saturated steam storage system.

[0022] Furthermore, the steam introduced via the charging device flows along the packing elements towards the ceiling. This increases the residence time of the condensate and steam. This process results in longer contact between the condensate and steam, which also has a positive effect on the charging capacity and the reaction rate of the saturated steam storage tank.

[0023] In an advantageous embodiment of the invention, a control valve is provided in the circulation device to close the circulation line as needed or to increase or reduce the circulation volume.

[0024] Preferably, the saturated steam storage tank is designed as a vertical container. This has a beneficial effect on the space required for the saturated steam storage tank.

[0025] In a preferred embodiment of the method, a pump pumps condensed water from a lower section of the container via the distribution device to the upper section of the container, so that the amount of water in the container remains unchanged by this process. In a corresponding embodiment of the method, the energy from the steam can be introduced into the saturated steam storage tank particularly efficiently.

[0026] Advantageously, steam for charging the saturated steam storage tank is fed into the tank in the upper section below the distribution device. This ensures that the condensate and steam remain in contact for a comparatively long time, which has a positive effect on the charging capacity and the reaction rate of the saturated steam storage tank.

[0027] In a particularly advantageous embodiment of the process, the saturated steam storage tank is charged to a maximum level where the water level formed by the condensed water reaches the upper area. This ensures that even at maximum charge, condensed water can be introduced into the steam via the distribution device.

[0028] Advantageously, to discharge the saturated steam storage tank, steam is drawn from the upper section of the tank, with the saturated steam storage tank being discharged only to the point where the water level formed by the condensed water reaches the lower section. This ensures that the minimum fill level is never undershot.

[0029] Further features and advantages of the saturated steam storage systems and the methods will become apparent from the following description of exemplary embodiments, with reference to the attached drawing.

[0030] The drawing shows each in a schematic cross-sectional representation. Fig. 1 a first embodiment of a saturated steam storage system, Fig. 2 a second embodiment of a saturated steam storage system, Fig. 3 a third embodiment of a saturated steam storage system and Fig. 4 a fourth embodiment of a saturated steam storage system.

[0031] Fig. 1 Figure 1 shows a first embodiment of the saturated steam storage unit for storing water vapor, comprising a container 2 in which water in the condensed state and as water vapor can be stored during operation, a loading device 4 for loading the saturated steam storage unit with water vapor, and a discharging device 6 for removing water vapor from the saturated steam storage unit.

[0032] The steam is located in container 2 above the water level formed by the condensed water. The saturated steam storage tank is designed as a vertical container 2.

[0033] The loading device 4 is equipped with a Fig. 1 The steam boiler (not shown) is connected via a line 8. The line 8 has a control valve 10. When the saturated steam storage tank is charged, the control valve 10 opens and steam flows into the tank 2. A line 14, also equipped with a control valve 12, leads from the discharge device 6, through which steam can be discharged from the saturated steam storage tank.

[0034] The saturated steam storage tank has a distribution device with a nozzle 16, through which atomized water can be introduced into an upper region of the tank 2. The nozzle 16 is supplied with condensed water via a circulation device 18. The circulation device 18 comprises a pump 20 and a circulation line 22, which is equipped with a control valve 24. A suction side of the pump 20 is connected to the lower region of the tank 2 via the circulation line 22. A pressure side of the pump 20 is connected to the nozzle 16 via the circulation line 22. During operation, the pump 20 pumps condensed water from the lower region of the tank 2 to the upper region of the tank 2 and introduces the condensed water as a droplet mist into the steam-filled upper region via the nozzle 16.

[0035] The lower area is defined by the minimum condensed water level limits that must be maintained during operation. This means that the circulation device 18 is arranged such that pump 20 can always pump condensed water out of tank 2 during operation. The area below the top of tank 2, which is filled with water vapor even at maximum fill level, is referred to as the upper area. Accordingly, the upper area is filled with water vapor at all times during operation.

[0036] The distribution device is always positioned so that water condensed during operation is introduced into the steam-filled area via nozzle 16.

[0037] Spraying condensed water into the upper part of container 2 effectively increases the contact area available for re-evaporation between the water vapor and the condensed water. Introducing condensed water into the area filled with water vapor creates a water surface of water droplets in addition to the water level. When water vapor is drawn from the saturated steam storage tank, evaporation occurs through both the water surface and the water droplets.

[0038] The larger the contact area available for evaporation, the greater the discharge rate; that is, the more water vapor can be extracted from the saturated steam storage system in a comparable time period. Furthermore, the discharge rate can be ramped up more quickly because the saturated steam storage system has a comparatively high reaction rate. These effects occur without requiring more space from the saturated steam storage system.

[0039] The introduction of condensed water also has a positive effect on the loading capacity. Due to the increased surface area of ​​condensed water, more water vapor introduced into container 2 above the water surface can condense within a comparable timeframe.

[0040] By introducing atomized water into the upper section of container 2 via a circulation device 18, the amount of water in container 2 remains constant, eliminating the need for complex control of the amount of water introduced and any water that may need to be drawn from the lower section. This allows energy to be transferred from the steam into the saturated steam storage tank with exceptional efficiency.

[0041] The introduction of steam into container 2 takes place during the process described in Fig. 1 In the illustrated embodiment, a first lance 26 is arranged in the upper region of the container 2. This first lance 26 feeds steam into the upper region of the container 2 below the nozzle 16 during the charging of the saturated steam storage tank. In contrast to saturated steam storage tanks known from the prior art, a saturated steam storage tank according to the invention makes it possible to introduce steam into the container 2 even above the water level. The water atomized in the upper region of the container 2 allows the steam supplied during charging of the saturated steam storage tank to be used for condensation above the water level. The steam does not necessarily have to be introduced into the container 2 below the water level during charging.

[0042] At the in Fig. 1 In the illustrated embodiment, the minimum fill level of the saturated steam storage tank is not limited by the position of the first lance 26. For this reason, the limit for the minimum fill level of condensed water to be maintained during operation can be reduced compared to saturated steam storage tanks known from the prior art, where steam must always be introduced below the water level. As a result, more steam can be extracted from the saturated steam storage tank with the same tank dimensions, at least if the nozzle geometry is designed accordingly. In the embodiment shown in Fig. 1 In the depicted saturated steam storage tank, the lower area defining the minimum filling level, for example, has a maximum height of 50% of the height of the tank.

[0043] In the upper section of the tank 2, the introduced steam encounters less resistance to the inflow compared to below the water level. To charge the saturated steam storage tank with steam, the pressure in the inlet line 8 connected to the charging device 4 must be greater than the pressure at the outlet of this line 8. Since the inflow resistance is lower than below the water level, more steam can be introduced into the saturated steam storage tank. Ultimately, a lower pressure differential is required to charge the saturated steam storage tank with steam than in conventional saturated steam storage tanks. For example, a saturated steam storage tank with an internal pressure of 20 bar could be charged with an inlet line at 21 bar. Conventional storage tanks would require a larger pressure differential, such as 5 bar, to introduce steam into the saturated steam storage tank. Fig. 1 In the depicted saturated steam storage tank, the upper area defining the maximum filling level, for example, has a height of at least 10% of the height of the tank.

[0044] Fig. 2 A second embodiment of a saturated steam storage device according to the invention is shown, in which a second lance 28 for introducing steam is provided in the lower region of the container 2. In the Fig. 2 In the illustrated embodiment, a control valve 10 is provided for each of the two lances 26 and 28. During the charging of the saturated steam storage tank, water vapor is fed into the tank 2 via the second lance 28 in addition to the first lance 26. The water vapor is injected through the second lance 28 below the water level, so that the water vapor introduced via the second lance 28 condenses in the condensed water. By providing the second lance 28 in addition to the first lance 26, the charging capacity of the saturated steam storage tank can be increased.

[0045] In contrast to the first embodiment, the one in Fig. 2 The depicted saturated steam storage tank has three nozzles 16 for introducing atomized water into the upper region of the tank 2. An increased number of nozzles 16 allows more condensed water from the lower region to be introduced into the upper region, thereby further increasing the contact area available for evaporation and condensation of the introduced steam between the steam and the condensed water.

[0046] In Fig. 3 A third embodiment of a saturated steam storage system according to the invention is shown. In this third embodiment, packing elements 32 are arranged on an intermediate floor 30 in the upper region. The intermediate floor 30 and the packing elements 32 are arranged below the nozzles 16 and above the first lance 26.

[0047] The condensed water introduced via the nozzles 16 migrates towards the bottom of the container 2 due to gravity. Condensate collects on the surface of the packing elements 32. This increases the contact area available for evaporation and condensation, which in turn has a positive effect on the charging and discharging performance as well as the reaction rate of the saturated steam storage tank.

[0048] Furthermore, the steam introduced via the first lance 26 flows along the packing elements 32 towards the ceiling of the container 2. This process results in the condensate and steam remaining in contact with each other for a longer period, which also has a positive effect on the charging capacity and the reaction rate of the saturated steam storage tank.

[0049] In Fig. 4 A fourth embodiment of a saturated steam storage device according to the invention is shown. In the fourth embodiment, the container 2 is pressurized to the same pressure as the one with a Fig. 4 The steam boiler not shown, connected to line 8, or as it is connected to one in Fig. 4 The load is supplied to the consumer (not shown) via line 14. The loading device 4 and the unloading device 6 share a common line to the tank 2. A steam control valve 34 is provided in line 14 leading to the consumer. Rapid load changes at the steam control valve 34, or on the boiler or consumer side, can be compensated for by the saturated steam storage tank. 2 Container 4 Loading device 6 Unloading device 8 Pipe 10 Control valve 12 Control valve 14 Pipe 16 Nozzle 18 Circulation device 20 Pump 22 Circulation line 24 Control valve 26 First lance 28 Second lance 30 Intermediate plate 32 Packing elements 34 Steam control valve

Claims

1. Saturated steam storage unit for storing water vapor comprising a container (2) in which water in the condensed state and as water vapor can be stored during operation, a loading device (4) for loading the saturated steam storage unit with water vapor and a discharging device (6) for removing water vapor from the saturated steam storage unit, characterized by the fact that a distribution device, in particular comprising at least one nozzle (16), for atomizing water in an upper area of ​​the container (2) is provided.

2. Saturated steam storage tank according to claim 1, characterized by the fact that A circulation device (18) with a pump (20) and a circulation line (22) is provided, wherein the circulation device (18) is designed in such a way that water condensed during operation from a lower area of ​​the container (2) can be introduced into the upper area of ​​the container (2) via the distribution device.

3. Saturated steam storage tank according to claim 1 or 2, characterized by the fact thatthe lower area is defined as the area extending from a lower bottom of the container (2), wherein the lower area has a height of at most 60%, in particular at most 50%, preferably at most 40% and particularly preferably at most 30% of a height of the container (2).

4. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that the upper area is defined as the area extending from an upper ceiling of the container (2), wherein the upper area has a height of at least 10%, in particular at least 15%, preferably at least 20% and particularly preferably at least 25% of the height of the container (2).

5. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that in the upper area a first lance (26) is provided for the introduction of steam, wherein the first lance (26) is preferably arranged below the distribution device.

6. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that In the lower area a second lance (28) is provided for the introduction of water vapor.

7. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that Packing elements (32) are provided in the upper area on an intermediate floor (30), wherein the packing elements (32) are arranged below the distribution device.

8. Saturated steam storage tank according to claims 5 and 7, characterized by the fact that the packing elements (32) are arranged above the first lance (26).

9. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that a control valve (24) is provided in the circulation device (18).

10. Saturated steam storage tank according to one of the preceding claims, characterized by the fact that the saturated steam storage tank is designed as a vertical container (2).

11. Method for operating a saturated steam storage unit according to one of claims 1 to 10, wherein a distribution device having in particular at least one nozzle (16) introduces condensed water into an upper area of ​​a container (2).

12. Method according to claim 11, characterized by the fact that a pump (20) pumps condensed water from a lower area of ​​the container (2) via the distribution device to the upper area of ​​the container (20).

13. Method according to claim 11 or 12, characterized by the fact that Water vapor for charging the saturated steam storage tank is supplied to the container (2) in the upper area below the distribution device.

14. Method according to any one of claims 11 to 13, characterized by the fact that The saturated steam storage tank is loaded to a maximum point where a water level formed by the condensed water reaches the upper area.

15. Method according to any one of claims 11 to 14, characterized by the fact thatTo discharge the saturated steam storage tank, steam is removed from the upper area of ​​the container (2), whereby the saturated steam storage tank is discharged to a maximum point at which the water level formed by the condensed water reaches the lower area.

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