JP2003503635A - Structural component and method for guiding media under high temperature and high pressure - Google Patents

Abstract

The present invention relates to a structural component for guiding a high-temperature medium (50) under a high-temperature pressure. The cold section (56) of the structural component surrounds the hot section (54) through which the hot medium (50) is guided. In the cold section (56), the cold medium (61) is conducted at a pressure of at least half the hot pressure, preferably at a pressure equal to or higher than the hot pressure. This reduces the load on the bulkhead (58) separating the cold section (56) from the hot section (54), thus allowing the structural component as a whole to have a relatively small wall thickness.

Description

Detailed Description of the Invention

The present invention relates to a structural component and the corresponding method designed to guide a hot medium under hot pressure and having a high temperature.

Karl Straus, “Power Plant Engineering (Kraftwerkstechnik)”
, 1997 Springer Verlag Berlin 3rd Edition (19
(Published in 1997) Page 303, Figure 12.2 shows steam turbine equipment of an energy generating power plant. In that case, feed water is supplied to the evaporator by a feed pump. The steam thus generated has its water removed in a steam separator and is supplied to a high-pressure steam turbine. The steam emitted from the high-pressure steam turbine is heated again by the reheater and supplied to the medium-pressure steam turbine. The steam from the medium-pressure steam turbine is subsequently supplied to the low-pressure steam turbine, and finally condensed in the condenser to be water again. The condensate is returned to the water supply tank, from where it is led again to the evaporator. Structural components for guiding steam under high temperature and high pressure are, for example, pipes between a steam turbine and an evaporator or a reheater, a steam turbine casing, a steam separator, a valve incorporated in the pipe, Also included are bypass devices for diverting steam in relation to the load, or collecting vessels not shown in detail for steam exiting the reheat process.

EP-A-0075072 shows a multi-shelled wall for separating different pressures, media and / or temperatures. The wall shells are spaced apart from each other and different pressures, media and / or temperatures are present in the intermediate chamber between the wall shells.

International Patent Application Publication No. WO 99/00620 shows a high temperature flange joint. The thermally loaded inner part of the hot flange joint is surrounded by a hollow chamber, through which a cooling medium for cooling the hot flange joint is guided.

The patent abstract of Japanese Patent No. 07233900 describes a gas conduit having an inner tube and an outer tube concentrically surrounding the inner tube. The inner pipe is flowed through by exhaust gas of high temperature and high pressure. In order to prevent the temperature of the hot gas in the inner tube from falling, a heat insulating material consisting of two layers is provided in the annular chamber between the inner tube and the outer tube. The heat insulating material is composed of a solid heat insulating layer provided on the inner surface of the outer tube and a static air layer existing in an annular chamber between the solid heat insulating layer and the outer surface of the inner tube. In this case, the pressure applied to the air layer can be adjusted by introducing compressed air into the annular chamber or by removing air from the annular chamber.

In DE-A 3421067, a main steam supply device in a high-pressure steam turbine is known. The main steam supply device has two inlet pipes, and these inlet pipes are concentrically arranged so as to form an intermediate chamber that is separable from an inner casing and an outer casing of the steam turbine. Cooling steam of lower temperature and lower pressure than the live steam in the inner inlet pipe is guided between the inner inlet pipe and the outer inlet pipe, and thus the difference in pressure exerted on the walls of the inner and outer inlet pipes of circular cross section. Also, the temperature difference between the walls of the inner and outer inlet tubes is reduced. The cooling steam is taken out from the intermediate stage of the steam turbine as a partially expanded steam through the extraction port and is supplied to the intermediate chamber, whereby the inner inlet pipe is cooled.

The object of the present invention is to provide a structural component that is particularly suitable for guiding high-temperature, high-pressure media. Another object of the invention is to provide a method for guiding a high temperature and high pressure medium.

[0008] The problem addressed by the present invention is, according to the invention, to guide a hot medium under hot pressure and having a high temperature, the hot part and at least partly surrounding the hot part. It is solved by a structural part having a cold part. The hot part is separated from the cold part by the partition. The low-temperature portion has a connection port for introducing a low-temperature medium that is lower in temperature than the high-temperature medium and is under a low-temperature pressure corresponding to at least the high-temperature pressure. The partition supports the pressure at high temperatures only without the action of the cold medium up to a maximum pressure, where the maximum pressure is less than the hot pressure. The hot pressure is usually the pressure at the hot part and the cold pressure is usually the pressure at the cold part.

The cold pressure during steady-state operation of the structural component is preferably at least as great as the hot pressure.

The present invention provides that the optionally increasing the higher temperature and / or the higher pressure for the hot medium to be guided in the structural component is achieved by increasing the wall thickness which bears the pressure.
It starts with the idea that this is not possible due to the loss of strong strength in structural parts. Such thick walls present great problems in terms of manufacturing techniques, for example metal wall casting techniques, in the case of metal structural component walls, and incur unacceptable considerable costs when using expensive refractory materials. The present invention provides another medium, a low temperature medium,
We propose a seemingly contradictory approach of guiding through structural components under considerable pressure, as with hot media, usually higher than hot media.

In that case, the cryogenic medium in the cold zone surrounds the hot zone in which the hot medium is guided. A partition separates the hot part from the cold part. The cold site is bounded by the outer wall. This causes, so to speak, functional separation for the purpose of the partition and the purpose of the outer wall which delimits the cold site. The partitions are first of all used to receive the thermal load of the hot medium. The partition wall must have a heat resistant material that can withstand the temperature of the hot medium. However, when the low temperature medium exerts an opposing pressure on the partition wall at the low temperature portion, the partition wall is sufficiently relieved from the high temperature pressure. That is, the low temperature medium acts as a supporting medium for the partition walls. The outer wall, which bounds the cold region, is suitable for being subjected to a pressure higher than the hot pressure at an acceptable wall thickness, since a lower temperature of the cold medium than the hot medium does not impair the strength of the outer wall. Thus, not only can the outer wall be made relatively thin, but it can also be made of a material that does not need to have heat resistant strength.

Therefore, according to the invention, on the one hand, a cost advantage is obtained by saving material in the partition wall and being able to utilize cheaper material in the outer wall. However, it is of great significance to be able to guide the hot medium through the structural parts at considerably higher pressures or considerably higher temperatures while maintaining the conventional wall thickness.

The structural component is preferably connected to a safety valve, by means of which the predetermined pressure difference between the cold pressure and the hot pressure cannot be exceeded.

Since the partition wall supports the pressure only at a pressure lower than the high temperature pressure at high temperature without the action of the low temperature medium by utilizing the advantages of the present invention, the partition wall is prevented from being completely loaded at the high temperature pressure. Action is taken. Accordingly, the safety valve prevents an unacceptably large pressure difference between the cold pressure and the hot pressure.

Before the valve in the hot part, an accumulator is preferably arranged which reduces the occurrence of impact effects during the valve switching process or the adjusting process.

The cold zone is preferably connected to an accumulator for the cold medium, so that a predetermined maximum pressure reduction rate in the cold zone cannot be exceeded. For example, when an accident occurs,
When the pressure in the cold medium drops momentarily, the accumulator ensures that the pressure in the cold medium drops only slowly. In that case, the accumulator is designed such that its pressure drop rate is slower than the adjustable pressure drop rate in the hot medium. Thus, the pressure in the hot medium can drop as quickly or faster as the pressure in the cold medium. This does not exceed the maximum allowable pressure difference between the cold and hot pressures. Exceeding the maximum allowable pressure difference impairs the stability of the partition.

The structural component preferably has an outlet remote from the inlet for the cryogenic medium, so that a continuous flow of the cryogenic medium at the cryogenic site can be regulated. When the low temperature portion is continuously flowed by the low temperature medium, no significant heating of the low temperature medium occurs, which may adversely affect the strength of the partition wall or the strength of the outer wall that bounds the low temperature portion.

Advantageously, the partition wall comprises a heat insulating material. The thermal insulation reduces heat loss from the hot medium. This heat loss can be undesirably high compared to a conventional structure without a cooling medium without thermal insulation, since the cooling medium provides cooling of the partitions. The heat insulating material can be provided, for example, outside the partition wall, that is, adjacent to the low temperature portion. However, the heat insulating material can be made, for example, in a layer adjacent to the inner surface of the partition, that is, at a high temperature portion, or as an intermediate layer inside the partition.

It is preferable that the high temperature portion is movably formed by a thermal action with respect to the low temperature portion. In particular, when the high temperature medium first flows into the high temperature portion and when the high temperature portion is heated accordingly, the high temperature portion undergoes large thermal expansion. This thermal expansion does not exist for the low temperature part because the low temperature part is kept at the temperature of the low temperature medium. By incorporating a suitable thermal expansion compensator in the hot part, for example by providing the partition with a bellows-shaped wall part, this hot part is thermally actuated so that unacceptably high thermal stresses do not occur.

Preferably, the structural part is formed as a pipe, the hot part is formed by the inner tube and the cold part is formed by the outer tube. Therefore, the tube wall of the inner tube is the partition wall or a part of the partition wall, and the tube wall of the outer tube is the outer wall that bounds the low temperature region.

Further preferably, the inner pipe is supported by the outer pipe so as to be movable along the pipe axis. In order to stabilize the inner tube, especially when the tube length is long, it is necessary to support the inner tube. By being movably supported along the pipe axis, the above-described movable structure of the high temperature part with respect to the low temperature part is ensured.

In a preferred embodiment of the invention, the inner tube is reinforced against crushing, in particular by a radially extending ring. Since the partition wall or inner tube wall is formed relatively thin by the supporting action of the cryogenic medium in the above-mentioned embodiment,
Reinforcing the inner tube is advantageous. This reinforcement is preferably provided by a radially extending ring provided in the inner tube, which ring, in another advantageous embodiment, in the thermal insulation provided in the inner tube, against the cryogenic medium. It is buried so as not to cause a large flow resistance.

The structural component is preferably formed as a valve. Indeed, in the case of complicatedly formed structural parts such as valves, a large wall thickness causes a great problem in terms of manufacturing technology. In particular, the casting of valve casing walls is difficult from a certain wall thickness. By reducing the wall thickness by separating the hot and cold regions, this problem is solved.

The hot medium is preferably steam or supercritical water. Also preferably, the cryogenic medium is steam and may be water. Preferably the structural component is a component of a steam turbine installation. The components of steam turbine equipment are particularly exposed to high temperatures and pressures. To meet the high temperature and high pressure composite requirements, already expensive specialty steels are utilized. Currently utilized materials, such as 10% chrome steel, have reached their use limit at metal temperatures of 620 ° C., with only a small amount of strength remaining. This causes, in some cases, extremely large wall thicknesses for structural parts which guide the steam and are under pressure. As a result, the casting limits of the valve casing and the turbine casing are reached, as mentioned above. A large wall thickness also means a high material cost and thus a high cost for the piping. Even before the material utilization limit is reached, the wall thickness required to receive the pressure is extremely high. Already for valve casings and collectors of steam from the heating process, at metal temperatures below 620 ° C. already a technical possibility, for example due to the limited castability and unstable poor performance of thick-walled structural parts. There will be a limit.

[0025] Preferably, the structural component is a collecting container for steam flowing out from the superheating process, a boiler for generating or heating steam, a steam separator for separating steam and water, or a steam turbine casing.

[0026] Preferably, the structural component is connected to the boiler such that the cold medium is fed to the boiler, where it is converted to the hot medium by heating. Thus, in this embodiment, the cold medium corresponds to the hot medium, which cold medium is led to the heating process, while the hot medium is led from the heating process. That is, the hot medium already heated in the boiler is
Exactly this heating is surrounded by the imminent medium. For example, in steam turbine equipment, feed water as a low temperature medium supplied to a boiler surrounds live steam as a high temperature medium generated from the feed water in the boiler. Similarly, the steam supplied to the reheat process surrounds the steam heated in the reheat process. In that case, not only is the temperature condition satisfied, i.e., the cold medium is colder than the hot medium, but the cold medium has at least the pressure of the hot medium, which allows it to support the partition wall. Can be used as a medium. Thus, preferably the outer pipe connects the feed pump to the boiler and the inner pipe connects the boiler to the steam turbine section in a flow-technical manner. Also preferably, the outer pipe connects the steam turbine part in the first pressure range and the inner pipe connects the boiler to the steam turbine part in the second pressure range at a pressure lower than the first pressure range in a technical manner. There is.

According to the invention, the problem addressed by the method is, in a method for guiding a hot medium under hot pressure and having a high temperature in a high-pressure region, the high-pressure region being refluxed by a cold medium, which The medium is solved by having a lower temperature than the hot medium and a cold pressure of at least one half of the hot pressure. The cold pressure is preferably at least as great as the hot pressure.

[0028]   The advantages of this method give rise to the advantages of structural components according to the above-mentioned construction.

Embodiments of the present invention will be described in detail below with reference to the drawings. It is shown in part schematically and not to scale. The same reference numerals have the same meaning in different drawings.

A steam turbine installation 80 is shown in FIG. The water supply tank 18 is connected to two water supply pumps 19 which are connected in parallel to each other, and a check valve 20 follows each of the water supply pumps 19. The pipes downstream of the check valves 20 are joined as a water supply pipe 23. The water supply pipe 23 communicates with the high pressure preheater 21. Flow-wise, bypass valves 22 are respectively arranged before and after the high-pressure preheater 21, and the high-pressure preheater 21 can be bypassed by these bypass valves 22. The high pressure preheater 21 is connected to the evaporator / economizer heat transfer surface 1. This evaporator / economizer heat transfer surface 1 is connected to the live steam superheater heat transfer surface 2. The live steam superheater heat transfer surface 2 is connected to the live steam superheater outlet header 3. The raw steam pipe 4 communicates with the raw steam valve 5 and the high-pressure bypass device 24 from the raw steam superheater outlet pipe 3. A pipe leads from the live steam valve 5 to the high-pressure turbine 6. From the high-pressure turbine 6, a reheater low-temperature pipe 7 communicates with a reheater heat transfer surface 8. The reheater heat transfer surface 8 is connected to the reheater outlet header 9. A high-temperature reheater pipe 10 communicates with the low-pressure bypass device 25 and the reheat steam valve (stop valve) 11 from the reheater outlet pipe header 9. The reheat steam valve 11 is connected to the intermediate pressure turbine 12. An overflow pipe 13 leads from the medium pressure turbine 12 to the low pressure turbine 14. The low pressure turbine 14 has a low pressure bypass device 2
The piping from 5 is also open. The low pressure turbine 14 is connected to the condenser 15.
The condenser 15 is connected to the condenser pump 16. Condensate pump 16 is low pressure preheater 1
Connected to 7. The low pressure preheater 17 is connected to the water supply tank 18.

In the operation of the steam turbine facility 80, the feed water is guided from the feed water tank 18 via the feed water pump 19 to the high-pressure preheater 21 where it is preheated. The feedwater preheated in this way is guided to the evaporator / economizer heat transfer surface 1 and the live steam superheater heat transfer surface 2 via the water supply pipe 23, and is heated there. The generated steam or supercritical heated water is collected in the superheater outlet header 3. The generated live steam is supplied to the high-pressure turbine 6 via the live steam pipe 4. The steam flowing out of the high-pressure turbine 6 is guided to the reheater heat transfer surface 8 where it is heated again. The reheated steam is collected in the reheater outlet header 9 and then supplied to the intermediate pressure turbine 12. And the expanded and cooled steam is
It is supplied to the low-pressure turbine 14 from the intermediate-pressure turbine 12 via the overflow pipe 13. The steam that has been further expanded and cooled there is sent from the low-pressure turbine 14 to the condenser 15, where it is condensed and condensed, and this condensed water is sent to the low-pressure preheater 17 via the condensate pump 16 and heated. , Is returned to the water supply tank 18. The steam supplied to the steam turbines 6, 12, 14 rotates a common steam turbine shaft (not shown). Due to the rotational energy thus generated, the generator 2 for generating electrical energy
7 is driven. Bypass devices 24, 25 are used to divert steam in relation to the load.

In the steam turbine facility 80, steam is guided at high temperature and high pressure. For example, the steam in the reheater hot pipe 10 has a temperature of 600-620 ° C. at a pressure of about 55 bar. The reheater cold pipe 7 guides steam at about 400 ° C. at a pressure of about 60 bar. The pressure difference is caused by the pressure loss of the boiler. The boiler, not shown here in detail, comprises heat transfer surfaces 1, 2, 8. The main steam temperature in the live steam pipe 4 is about 600 ° C. at a pressure of about 250-300 bar. Water supply pipe 2
The water supply in 3 is about 3 at a pressure still 40-50 bar higher than the main steam pressure.
It has a temperature of 50 ° C. This high temperature and high pressure requires a fairly large wall thickness for the structural components that guide the steam and an expensive refractory steel construction, for example 10% chrome steel. In the prior art implementation shown in FIG. 1, the structural component is
It has a single structural wall that is subject to pressure and temperature. Along with this, the thick-walled structural parts are not only difficult to manufacture (cast) and have a high material cost, but the thick-walled structural parts also have a temperature change, for example, during start-up or load fluctuation. Limit the allowable speed of.

FIG. 2 shows a steam turbine installation 80 corresponding to that of FIG. 1, in which a completely new concept is used, in particular for structural components loaded under pressure and temperature. For example, the live steam pipe 4 is formed as an inner pipe within the outer pipe (see FIG. 3), the outer pipe of which forms the water supply pipe 23. Similarly, the reheater high temperature pipe 10 is also an inner pipe, and the inner pipe is surrounded by the reheater low temperature pipe 7 as an outer pipe. As a result of this formation, the hot medium, for example the live steam or the reheated steam, is surrounded by the cold medium, for example the feed water or the steam to be superheated. The cold medium has a higher pressure than the hot medium. Accordingly, since each cryogenic medium is used as a supporting medium for supporting the inner pipe, each inner pipe can be formed with a thin wall thickness. The walls of each outer tube also can be made thin or made of a relatively inexpensive material, as the strength does not decrease due to high temperatures. In the same way, superheater outlet heading 3,9
Alternatively, the valves 5, 11 or also the bypass devices 24, 25 are designed such that the hot medium to be guided is surrounded by the cold medium. A water injection nozzle 29 is provided at a suitable location for injecting water to further cool the cryogenic medium, for any additional cooling required for the cryogenic medium. Superheater outlet heading 3,9
The bypass devices 24, 25 and the valves 5, 11 are equipped with an outlet 28 for the cold medium, so that a defined flow rate can be adjusted for the cold medium. The outer pipe, for example the water supply pipe 23 or the reheater cold pipe 7, is provided with an accumulator 30 for the cold medium so that no instantaneous pressure drop in the cold medium occurs. The momentary pressure drop causes an excessive pressure difference between the hot pressure on the hot medium and the cold pressure on the cold medium, which loads each inner tube unacceptably high. Furthermore, the safety valve 26 ensures that no unacceptably large pressure difference is created between the hot and cold pressures. Next, the configuration for each structural component will be described in detail.

FIG. 3 shows the pipe 69 in a cross-sectional view. Inner tube 70 is surrounded by thermal insulation 68. The heat insulating material 68 is covered with a jacket 100. The wall of the inner tube 70 forms a partition 58 with the heat insulating material 68 and the jacket 100. This partition 58
Are coaxially surrounded by the outer tube 72 and coaxially with the tube axis 73. Between the partition wall 58 and the outer tube 72, the low temperature portion 5 for guiding the low temperature medium 61.
6 is formed. The inner tube 70 surrounds the hot zone 54 in which the hot medium 50 is guided. The pipe 69 is in particular a steam pipe of a steam turbine facility, the hot medium 50 and the cold medium 61 of which are steam, or the cold medium 61 of which is water. The jacket 100 has through holes 102 that are used to balance the pressure and / or drain the thermal insulation 68. The cold medium 61 is preferably in a cold pressure state at least as large as the hot pressure of the hot medium 50. As a result, the partition wall 58 is supported and the pressure load is reduced. Therefore, the partition 58, and in particular the inner tube wall of the inner tube 70, can be made relatively thin. However, even when the thickness of the partition wall 58 is kept relatively large, the high temperature medium 50 can have a higher high temperature pressure or a higher temperature. Since the outer tube 72 is only slightly thermally loaded, there are no critical temperature-based strength problems for the material. Therefore, the outer tube 72 can also be made relatively thin. Alternatively, inexpensive materials can be used.
However, it is also possible to leave the normal wall thickness and have a large pipe cross-sectional area, which reduces the flow losses in the cold medium 61 as well as the hot medium 50.

FIG. 4 shows a different configuration of the inner tube 70 for the thermal insulation 68. In this case, the heat insulating material 68 is formed as an inner layer of the inner tube 70. In Figure 5,
Another possible arrangement of thermal insulation 68 is shown. Here, the heat insulating material 68
Is incorporated as an intermediate layer inside the wall of the inner tube 70.

In FIG. 6, an inner tube 70 surrounded by a heat insulating material 68 is shown in a longitudinal sectional view. The inner tube 70 is surrounded by a radially extending reinforcing ring 74. This avoids dents despite the relatively thin inner tube 70. Since the reinforcing ring 74 is incorporated in the heat insulating material 68, the flow resistance does not increase with respect to the low temperature medium 61 flowing therethrough.

7-9 each show in longitudinal section an embodiment of the inner tube 70 provided with means for absorbing thermal expansion. In FIG. 7, a bellows-like expansion compensator 200 is incorporated into the inner tube 70. In FIGS. 8 and 9, a packing element 206, which is movable by the action of heat, is arranged in a groove 204, which is axially oriented and radially rotated. A retaining element 207 retains the end of this packing element 206 opposite the groove 204. Due to the split construction of the inner tube 70, the inner tube 70 is allowed to expand thermally and is sealed by the packing element 206 which is movable in the groove 204.

FIGS. 10 to 12 respectively show cross-sectional views of an embodiment of the pipe 69 including the inner pipe 70 and the outer pipe 72. The inner tube 70 is supported by an outer tube 72 in order to receive possible tube forces or gravity of the inner tube 70 as well as to adjust the oscillatory behavior of the tube 69. To that end, the support element 300 is held in the guide element 302 so as to be movable by axial and radial thermal action. In order to reduce the flow resistance to the cold medium 61, it is advantageous to have as few support points as possible. The embodiment in FIG. 12 is particularly advantageous for reducing the flow resistance.

In FIG. 13, an inner tube support device with a support element 300 held in a guide element 302 is shown in an enlarged sectional view. 14 and 15 respectively,
The construction of the flow-technically good guide element 302 is shown in a sectional view perpendicular to the support element 300.

In FIG. 16, an axial fixation device 318 for the inner tube 70 is shown. The fixing pin 322 is engaged with the inner pipe protrusion 320. The fixing pin 322 is the outer tube 72.
And is retained by a lid 323 on the outside of the outer tube 72. A flow-technically advantageous design of the inner tube projection 320 is shown in cross section in FIG.

FIG. 18 is a vertical cross-sectional view showing a part of the pipe 69 formed of the inner pipe 70 and the outer pipe 72. The inner tube 70 is supported by the outer tube 72 by the supporting device 300, and is fixed in the axial direction at the fixing place 318. The thermal expansion compensator 200 in the inner tube 70 allows thermal movement of the inner tube 70 with respect to the outer tube 72.

In FIG. 19, the pipe 69 bent at a right angle is shown in a vertical sectional view. The thermal expansion starting point 500 of the pipe 69 is at the maximum curvature portion.

In FIG. 20, the branch pipe 69 is shown in a vertical sectional view. Here, the thermal expansion start point 500 is a branch point.

In FIG. 21, the superheater outlet header 3 is shown in cross section. Its inner container 6
01 forms the high temperature portion 54, and the low temperature portion 56 formed by the outer container 603.
Be surrounded by.

In FIG. 22, the pipe protrusion 600 is shown in a sectional view. High-temperature steam is introduced into the high-temperature portion 54 via the piping portion 602. The pipe section 602 is bounded by an inner wall 608. The outer wall 604 guides the cold region 56 onto the inner wall 608. A possible manufacture is a projecting member 60 along the weld seam A on the inner wall 608.
6 welding, followed by welding of the half shells B and C of the outer wall 610 (
(See FIG. 23).

FIG. 24 shows a different manufacturing method in which the protruding member 606 is screwed by the bolt joint 620. The seal between the hot part 54 and the cold part 56 is
This is done by packing 622 that can be fixed in the axial direction to allow thermal expansion.

FIG. 25 is a longitudinal sectional view showing a movable structure by the heat action on the superheater outlet pipe header 3.

FIG. 26 shows the steam turbine valve 5 in a longitudinal sectional view. The steam turbine valve 5 includes an emergency stop valve 704 and a regulating valve 706. The valve stem 700 opens and closes the safety valve 704 with respect to its valve seat 710. The valve rod 708 is the adjusting valve 706.
Is opened and closed with respect to its valve seat 712. The hot steam 54 reaches the regulating valve 706 through the open emergency stop valve 704 via the inlet pipe 714 and exits the steam turbine valve 5 through the discharge pipe 716 depending on the opening degree of the regulating valve 706. At the inlet portion of the steam turbine valve 5, a high temperature portion 54 for the high temperature steam 51 is a low temperature portion 56 for a low temperature medium, especially for steam.
It is formed of a double-walled structure so as to be surrounded by. This brings the advantages mentioned above for the wall thickness of the structural component. Especially when the wall structure of the valve 5 is complex, good castability results due to the reduced wall thickness. The outlet 28 for the low temperature medium is
It is preferably connected to another turbine part in such a way that cooling occurs in that turbine part. In that case, in order to ensure a proper flow-through of the valve body, a certain amount of enclosing medium is always discharged from the enclosure via the outlet 28 and is covered by other steam turbine components (not shown). Guided to the cooling site. The discharge from the enclosure must be shaped so that stagnation of the cryogenic medium is eliminated. The introduction into the cooled area ensures that the cold medium does not produce undesired turbine power (i.e. unintentional high speed rotation of the turbine) during an emergency stop of the turbine (e.g. due to a sudden load drop). Must be implemented. Furthermore, at low loads (i.e. low hot steam entrainment), unacceptable wet steam must be prevented from forming during the steam expansion process.

FIG. 27 shows the high-pressure steam turbine 6 in a vertical sectional view. External vehicle compartment 804
Surrounds the interior compartment 802. Between the inner compartment 802 and the outer compartment 804,
There is a gap 803 into which the low temperature medium is introduced. The cold medium then has a higher pressure than the hot steam, and the hot steam is guided through the inner casing 802, causing the shaft 808 to rotate via turbine blades (not shown). As a result, a supporting action is generated with respect to the inner casing 802, so that the inner casing 802 can be formed thin. Furthermore, the outer casing 804 can be manufactured in thin-walled and / or inexpensive materials, based on the advantages described above.

Next, the requirements for various operating conditions in the above-described configuration of the structural parts of the steam turbine equipment will be discussed.

A) Rated Operation and Output Fluctuation During normal operation, since the pressure increase different from the pressure increase by the boiler feed water pump does not occur, the pressure of the boiler feed water pump decreases only in the flow direction. At a given mass flow rate> 0, pressure loss is always formed between the feed water and the main steam and between the reheater low temperature pipe and the reheater high temperature pipe, so the condition that the high temperature pressure is lower than the low temperature pressure must be met. It is filled.

When the mass flow rate decreases (for example when the feed water supply is low), the storage capacity of the accumulator is partially emptied and it is expected that the above conditions are also maintained during this time. The rapid increase in mass flow rate increases the pressure differential, which must be dealt with by the design of the closed piping.

The rapid opening of the throttled regulating valve lowers the pressure in the pipe upstream of it. An accumulator is provided near the valve to delay the pressure drop when the design of the closed tubing must be determined by this load drop. This procedure is also effective for load conditions that rapidly and partially close the valve.

B) Light Load Operation / High Pressure Ventilation Operation Consider the reheater piping during light load operation. When the output is reduced to a low load (i.e., the steam mass flow rate is reduced), the pressure in the reheater low temperature pipe as well as the pressure in the reheater high temperature pipe decreases. In addition, since the boiler pressure loss decreases when the mass flow rate is low, the pressure difference between those pressures also decreases. Therefore, the stress of the reheater high temperature piping is reduced. However, during light load operation, the high-pressure exhaust steam temperature increases (high-pressure ventilation operation). This is also the case with the prior art arrangements, which must be endured by the reheater cryogenic piping. In this case, the reheater high temperature piping wall or another object to be protected (heading, valve casing) cannot be effectively cooled by the reheater low temperature steam. When a given object requires constant cooling (cooling steam for thick-walled structural parts that cannot be rapidly and sufficiently recooled when the output is rapidly consumed after being heated for a long time in light load operation) , Or cooling steam for rotating structural components), water injection cooling (ie cooling by injecting water into the steam), relative to the central unit in the high-pressure exhaust steam flow, and locally in front of each protected object.
You can It is also conceivable to use an (existing) high-pressure bypass device for cooling, ie the high-pressure bypass device is slightly opened at light load and the passing steam is cooled by pouring water. After entering the high-pressure exhaust steam, cooling of the entire exhaust steam is achieved. After mixing in the high-pressure exhaust steam, cooling of the entire exhaust steam is achieved, and the post-mixing pipe can branch to the object to be protected.

C) Emergency closing and emergency closing test of valve When a valve is emergency closed, a momentary impact action occurs. This shocking action is caused by the sudden deceleration of the flow. The magnitude of the impact action is determined in particular by the steam mass flow rate, the length of the pipe upstream of the safety valve, the speed of sound of the steam in the pipe and the closing time of the valve. The design of hermetically sealed components must address this momentary pressure rise condition. The magnitude of the impact action is reduced by placing an accumulator immediately in front of the valve. During valve testing, a particularly high steam mass flow flows through the valve, but the hot pressure is expected to increase compared to normal operation. In the event of a high-speed closure that might occur, a large impact action occurs. This situation is the basis for the dimensions of hermetically sealed components and accumulators.

D) Bypass Operation During the bypass operation, the partial turbine is bypassed by introducing the steam through the bypass device. Thereby, the pressure and temperature of the steam returning to the boiler are made sufficiently low for the boiler (cooling of the reheater heat transfer surface), ie also for the reheater cold pipe / reheater cold component.

E) Response of Boiler Safety Valve The boiler has a water supply safety valve, a main steam safety valve, a reheater low temperature piping safety valve, and a reheater high temperature piping safety valve. When a safety valve is opened, the generation of unacceptable pressure differences is prevented by opening the corresponding safety valve (safety valves for hot and cold media are
Protect against maximum pressure, respectively, and against common maximum pressure difference).

F) Pause of Feed Water Heating When the feed water preheater is damaged (for example, when the heat exchanger leaks), the feed water preheater is shut off and bypassed. The rapid decrease in the feed water temperature resulting from this causes unstable thermal stress in the structural component washed by the feed water, and must be taken into consideration when designing the component. Since its thermal stress increases with wall thickness and flow velocity, thick wall structural components must be washed out at a reasonable rate (component encapsulation is not in the main water supply).

G) Halting of the water feed pump Halting of the water feed pump, for example, because cooling of the boiler heat transfer surface is no longer guaranteed,
It is a serious accident for the entire power plant. In this case, the check valve prevents the feed water from flowing back through the pump. Therefore, a pressure drop in the water supply pipe below the pressure of the main steam pipe surrounded by the water supply pipe is prevented. Therefore, even in the case of this accident, reliable survival is achieved.

H) Boiler Shutoff Mechanism Closure As already mentioned, the differential pressure between the hot and cold pressures must be monitored and protected by a protective device (safety valve). A fault shut-off mechanism that is closed and cannot be re-opened during shutdown results in a large differential pressure at start-up, which causes the protective device (which cannot be shut off according to the rules) to respond.

[Brief description of drawings]

[Figure 1]   Conventional steam turbine equipment.

FIG. 2 shows a steam turbine installation with structural components for high temperature steam guidance surrounded by low temperature protection steam.

[Figure 3]   FIG. 3 is a cross-sectional view of a pipe having an inner pipe and an outer pipe.

[Figure 4]   An inner tube according to FIG. 3 with one construction of thermal insulation.

[Figure 5]   An inner tube according to FIG. 3 with another configuration of thermal insulation.

[Figure 6]   FIG. 3 is a vertical cross-sectional view of a pipe having a reinforced inner pipe.

[Figure 7]   FIG. 3 is a vertical cross-sectional view of an inner tube provided with a bellows-like thermal expansion compensator.

[Figure 8]   Inner tube with movable packing due to thermal action.

[Figure 9]   Inner tube with movable packing due to thermal action.

[Figure 10]   FIG. 3 is a cross-sectional view of piping with a supported inner tube.

FIG. 11   FIG. 3 is a cross-sectional view of piping with a supported inner tube.

[Fig. 12]   FIG. 3 is a cross-sectional view of piping with a supported inner tube.

[Fig. 13]   Sectional drawing of the support device which can move the axial direction of an inner pipe.

FIG. 14   FIG. 4 is a cross-sectional view of an inner tube support device that is well formed in terms of flow technology.

FIG. 15   FIG. 4 is a cross-sectional view of an inner tube support device that is well formed in terms of flow technology.

FIG. 16   Inner tube support device that is fixed axially.

FIG. 17   FIG. 17 is a cross-sectional view of the inner tube support device of FIG. 16.

FIG. 18   Piping with inner pipe, outer pipe, support device and thermal expansion compensator.

FIG. 19   Right angle bent pipe with inner pipe and outer pipe.

FIG. 20   Branch pipe with inner pipe and outer pipe.

FIG. 21   FIG. 3 is a cross-sectional view of the reheater outlet pipe assembly.

FIG. 22   The expanded sectional view of the inlet pipe of the reheater outlet pipe side.

FIG. 23   The external view of the inlet pipe in FIG.

FIG. 24   Different configurations of reheater header inlet pipe.

FIG. 25   Sectional drawing of a movable structure by the thermal action of a reheater pipe head.

FIG. 26   The longitudinal cross-sectional view of a steam turbine valve.

FIG. 27   FIG. 3 is a vertical sectional view of a high-pressure steam turbine.

[Explanation of symbols]

19 water supply pump 26 Safety valve 28 outlet 30 accumulator 50 high temperature medium 54 Hot part 56 cold site 58 bulkhead 61 low temperature medium 68 thermal insulation 69 plumbing 70 Inner tube 72 Outer tube 73 Piping axis 74 Reinforcement ring 80 Steam turbine equipment

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F22B 37/10 F22B 37/10 L 37/20 37/20 Z // B01D 1/30 B01D 1/30 A

Claims (22)

[Claims] 1. A hot part (54) and a hot part (5) of a structural part defined for guiding a hot medium (50) under hot pressure and having a high temperature.
4) at least partially surrounding the cold site (56) and a partition (58) separating the hot site (54) from the cold site (56), the cold site (56) being the hot medium (50). The partition wall (58) has a connection port for introducing a low temperature medium (61) at a low temperature lower than that of at least under a low temperature pressure corresponding to the high temperature pressure, and the partition wall (58) does not have the action of the low temperature medium (61) at a high temperature. Structural parts that support pressure only up to the maximum pressure that is lower than the high temperature pressure. 2. The structural component according to claim 1, which is connected to a safety valve (26) such that a predetermined pressure difference between the cold pressure and the hot pressure cannot be exceeded by the action of this safety valve (26). 3. The cold region (56) is connected to an accumulator (30) for the cold medium (61) so that a predetermined maximum rate for pressure reduction in the cold region (56) cannot be exceeded. The structural component according to 1 or 2. 4. An outlet (28) remote from the inlet for the cryogenic medium so that the continuous flow of the cryogenic medium (61) to the cryogenic region (56) is adjustable. The structural component according to any one of 1. 5. The structural component according to claim 1, wherein the partition wall (58) has a heat insulating material (68). 6. The structural component according to claim 1, wherein the high-temperature portion (54) and the low-temperature portion (56) are formed so as to be movable by a relative thermal action. 7. The hot section (54) is formed as a pipe (69) and the hot section (54) is an inner pipe (
7. Structural component according to any one of the preceding claims, characterized in that it is formed by 70) and the cold section (56) is formed by the outer tube (72). 8. The structural component according to claim 7, wherein the inner pipe (70) is movably supported on the outer pipe (72) along the pipe axis (73). 9. Structural component according to claim 7 or 8, wherein the inner tube (70) is reinforced against dents, in particular by means of a ring (74) extending radially. 10. The structural component according to claim 1, which is embodied as a valve. 11. The structural component according to claim 1, wherein the high-temperature medium (50) is steam or supercritical pressure water. 12. The structural component according to claim 1, wherein the cold medium (61) is steam or water. 13. Structural component according to claim 11 or 12, which is formed as a component of a steam turbine installation (80). 14. Structural component according to claim 13, which is formed as a collecting container, in particular for the hot medium (50) resulting from the reheating process. 15. The structural component according to claim 13, which is formed as a boiler for generating or heating steam. 16. The structural component according to claim 13, which is embodied as a steam separator. 17. The structural component according to claim 13, which is formed as a steam turbine casing. 18. The method as claimed in claim 13, wherein the cold medium (61) is fed to the boiler and is connected to the boiler so that it is converted into the hot medium (50) by heating there.
The structural component according to any one of 14, 16, and 17. 19. Structure according to claim 13 or 7, wherein the outer pipe (72) flow-mechanically connects the feed pump (19) to the boiler and the inner pipe (70) fluidly connects the boiler to the steam turbine section. parts. 20. An outer pipe (72) directs the steam turbine portion of the first pressure range to the boiler, and an inner pipe (70) directs the boiler to the steam turbine portion of the second pressure range at a lower pressure than the first pressure range. 8. The structural component according to claim 13, wherein the structural components are connected by flow technology. 21. A method for guiding a hot medium (50) under high temperature pressure and having a high temperature in a high pressure section (54), wherein the high pressure section (54) is refluxed with a cold medium (61), A guiding method in which the cold medium (61) has a lower temperature than the hot medium (50) and has a cold pressure that is at least half the hot pressure. 22. The method of claim 21, wherein the cold pressure is at least as great as the hot pressure in the steady operating range.