MOISTURE SEPARATOR REHEATER

TECHNICAL FIELD

The present invention relates to a moisture separator reheater for generating superheated steam by separating moisture from steam and heating the steam. In particular, the present invention is extremely effective in nuclear power plants when implemented for utilizing steam that has been used in a high-pressure steam turbine, again in low-pressure steam turbines.

BACKGROUND ART

In a nuclear power plant, steam used in a high-pressure steam turbine is used again in a low-pressure steam turbine. If the steam contains moisture (around 12%), this causes not only erosion of turbine blades but also a decrease in thermal efficiency of the turbine. Accordingly, a moisture separator reheater is used which generates superheated steam by separating moisture from the steam discharged from the high-pressure steam turbine (moisture content is reduced to approximately 0.1%) and heating the steam, and which feeds the superheated steam to the low-pressure steam turbines.

As such a moisture separator reheater, a two-stage reheat one has been known, for example, such as described in Patent Document 1 below. In this double-reheat moisture separator reheater, steam from a high-pressure steam turbine flows into a steam receiving chamber in a horizontal and cylindrical shell body through a steam receiving opening provided in a lower central portion of the shell body, collides with a baffle plate, divides into two directions toward two axial end sides of the shell body to rise, flows into supply manifold chambers provided on each of the two axial end sides of the shell body, flows into moisture separation chambers through slits of distributor plates, and undergoes moisture separation in mist separators.

The steam from which moisture has been separated flows into a heating chamber provided in a portion containing the central axis of the shell body, undergoes first-stage heating in first-stage heater tube groups and then second-stage heating in second-stage heater tube groups, and is thereafter sent out to a low-pressure steam turbine from a steam delivery opening provided in an axially central portion of an upper portion of the shell body.

PATENT DOCUMENT 1: JP-A-7-301691

DISCLOSURE OF INVENTION
Problems to be Solved by the Invention

With regard to a moisture separator reheater such as described above, a structure described below has been studied. Specifically, a heating chamber provided in a portion containing the central axis of a shell body is divided into two chambers on two axial end sides of the shell body. Over the heating chambers, a collection manifold chamber communicating throughout the axial length of the shell body is provided. Moreover, a partition plate is provided in a way to separate the respective sections of the collection manifold chamber and the steam receiving chamber. Further, a plurality of (e.g., three) steam delivery openings in an upper portion of the shell body are provided in the axial direction of the shell body.

However, in the above-described structure, the steam receiving chamber through which low-temperature steam circulates and the collection manifold chamber through which high-temperature steam circulates are adjacent to each other with the partition plate interposed therebetween. Accordingly, pre-reheated steam fed into the steam receiving chamber decreases the temperature of steam near the partition plate, i.e., in a space part, adjacent to the steam receiving chamber, in the collection manifold chamber.

Thus, in such a structure as described above, the temperature of steam sent out from the steam delivery opening located above the partition plate, i.e., located in an axially central portion of the shell body and connected to a space part adjacent to the steam receiving chamber, is lower than the temperature of steam sent out from the steam delivery openings located on the two axial end sides of the shell body. Accordingly, there is the problem of the decrease in thermal efficiency of a low-pressure steam turbine fed with the steam from the steam delivery opening located in the axially central portion of the shell body.

Against such circumstances, an object of the present invention is to provide a moisture separator reheater which can prevent a decrease in temperature of steam sent out.

Means for Solving the Problems

In order to solve the above-described problems, a moisture separator reheater according to a first invention comprises a shell body provided inside with: a steam receiving chamber having a steam receiving opening for receiving steam; a supply manifold chamber communicating with the steam receiving chamber; a moisture separation chamber communicating with the supply manifold chamber and separating moisture from the steam; a heating chamber communicating with the moisture separation chamber and heating the steam; and a collection manifold chamber being disposed adjacent to the steam receiving chamber, communicating with the heating chamber, and having a steam discharge opening for discharging the steam. The moisture separator reheater is characterized by comprising heat-conduction reducing means for reducing heat conduction between the adjacent sections respectively of the steam receiving chamber and the collection manifold chamber of the shell body.

A moisture separator reheater according to a second invention is characterized in that in the first invention, the heat-conduction reducing means is a hollow partition member disposed to separate the adjacent sections respectively of the steam receiving chamber and the collection manifold chamber, and the partition member has communicating holes allowing the collection manifold chamber and an inside of the partition member to communicate with each other so as to receive therein the steam circulating in the collection manifold chamber and to return the received steam to the collection manifold chamber.

A moisture separator reheater according to a third invention is characterized in that in the first invention, the heat-conduction reducing means is a partition member which has a heat insulating layer therein and which is disposed to separate the adjacent sections respectively of the steam receiving chamber and the collection manifold chamber.

A moisture separator reheater according to a fourth invention is characterized in that in the first invention, the heat-conduction reducing means is an arrangement of the steam discharge opening, and the steam discharge opening is connected only to a space part of the collection manifold chamber other than a space part adjacent to the steam receiving chamber.

EFFECTS OF THE INVENTION

In a moisture separator reheater according to the present invention, since the heat-conduction reducing means reduces the heat conduction between the adjacent sections respectively of the steam receiving chamber and the collection manifold chamber of the shell body, a decrease in temperature of steam sent out from a steam delivery opening can be prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view schematically showing the configuration of a first embodiment of a moisture separator reheater according to the present invention and showing a cross section containing the central axis thereof.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 as seen in the direction of arrows II.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 as seen in the direction of arrows III.

FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1 as seen in the direction of arrows IV.

FIG. 5 is a schematic diagram showing the configuration of a crown plate in FIGS. 1 and 2.

FIG. 6 is a view schematically showing the configuration of a second embodiment of a moisture separator reheater according to the present invention and showing a cross section containing the central axis thereof.

FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 as seen in the direction of arrows VII.

FIG. 8 is a schematic diagram showing the configuration of a crown plate in FIGS. 6 and 7.

FIG. 9 is a view schematically showing the configuration of a third embodiment of a moisture separator reheater according to the present invention and showing a cross section containing the central axis thereof.

FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9 as seen in the direction of arrows X.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a moisture separator reheater according to the present invention will be described with reference to the drawings.

However, the following embodiments do not limit the present invention.

First Embodiment

Hereinafter, a first embodiment of a moisture separator reheater according to the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a view schematically showing the configuration of the moisture separator reheater and showing a cross section containing the central axis thereof. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 as seen in the direction of arrows II. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 as seen in the direction of arrows III. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1 as seen in the direction of arrows IV. FIG. 5 is a schematic diagram showing the configuration of a crown plate in FIGS. 1 and 2.

As shown in FIGS. 1 to 3, a cylindrical shell body 111 is oriented so that the axis thereof may be directed in a horizontal direction, and a steam receiving chamber 111a is formed in an axially central portion, except an upper portion, of the inside of the shell body 111. In a lower portion of the axially central portion of the shell body 111, a plurality of steam receiving openings 112a and 112b are provided which feed steam 1 discharged from a high-pressure steam turbine to the inside of the steam receiving chamber 111a. Inside the steam receiving chamber 111a, a U-shaped baffle plate (buffer plate) 113 is disposed which guides the flow of the steam 1 while alleviating the impact of the steam 1 from the steam receiving openings 112a and 112b.

As shown in FIGS. 2 to 4, on each of the axial two ends of the inside of the shell body 111, supply manifold chambers 111b communicating with the steam receiving chamber 111a are formed in radially outer portions of the inside of the shell body 111 on the upper side thereof except an upper portion thereof. Each of lower portions of these supply manifold chambers 111b is a distributor plate 114 having a large number of slits 114a formed therein.

On each of the two axial end sides of the inside of the shell body 111, moisture separation chambers 111c are formed in radially outer portions of the inside of the shell body 111 on the lower side thereof, i.e., under the supply manifold chambers 111b. Inside each of these moisture separation chambers 111c, a mist separator 115 connected to the slits 114a of the distributor plate 114 is disposed.

As shown in FIGS. 1 and 4, on each of the two axial end sides of the inside of the shell body 111, a heating chamber 111d communicating with the moisture separation chambers 111c is formed in a radially inner portion of the inside of the shell body 111, i.e., in a region surrounded by the supply manifold chambers 111b and the moisture separation chambers 111c. On the lower side of the inside of each of the heating chambers 111d, a U-shaped first-stage heater tube group 116 is disposed so that a tube end portion thereof may be directed toward an axial end portion of the shell body 111. On the upper side of the inside of each of the heating chambers 111d, a U-shaped second-stage heater tube group 117 is disposed so that a tube end portion thereof may be directed toward an axial end portion of the shell body 111.

On each of the axial two end sides of the inside of the shell body 111, a first-stage heater steam chamber 118 having the inside thereof partitioned into a distributing chamber 118a and a collection chamber 118b is provided in a radially inner portion of the inside of the shell body 111 on the lower side thereof. On each of the two axial end sides of the shell body 111, a second-stage heater steam chamber 119 having the inside thereof partitioned into a distributing chamber 119a and a collection chamber 119b is provided in a radially inner portion of the inside of the shell body 111 on the upper side thereof.

In the distributing chambers 118a and 119a of the heater steam chambers 118 and 119, steam supply openings 118c and 119c supplied with steams 2 and 3 for heating are provided, respectively. In the collection chambers 118b and 119b of the heater steam chambers 118 and 119, steam discharge openings 118d and 119d for discharging the steams 2 and 3 used for heating are provided, respectively.

To the distributing chambers 118a of the first-stage heater steam chambers 118, one tube end portions of the first-stage heater tube groups 116 are connected, respectively. To the collection chambers 118b of the first-stage heater steam chambers 118, the other tube end portions of the first-stage heater tube groups 116 are connected, respectively. To the distributing chambers 119a of the second-stage heater steam chambers 119, one tube end portions of the second-stage heater tube groups 117 are connected, respectively. To the collection chambers 119b of the second-stage heater steam chambers 119, the other tube end portions of the second-stage heater tube groups 117 are connected, respectively.

As shown in FIGS. 1, 2, and 4, in an upper portion of the inside of the shell body 111, a collection manifold chamber 111e communicating with the heating chambers 111d is formed continuously in the axial direction of the shell body ill. In the two axial end sides and the axially central portion of an upper portion of the shell body 111, steam delivery openings 120a to 120c are provided which communicate with the collection manifold chamber 111e to send out the steam 1 to low-pressure steam turbines, respectively.

As shown in FIGS. 1, 2, and 5, the adjacent sections respectively of the steam receiving chamber 111a in the axially central portion of the inside of the shell body 111 and the collection manifold chamber 111e are partitioned by a crown plate 121. The crown plate 121 is a hollow partition member, and serves as heat-conduction reducing means. The crown plate 121 includes a horizontal plate 121a and a tilted plate 121b which is on each of two sides of the horizontal plate 121a with respect to the radial direction of the shell body 111 so that outer portions of the shell body 111 with respect to the radial direction thereof may be located upward.

In each of two end side surfaces of the horizontal plate 121a of the crown plate 121 with respect to the axial direction of the shell body 111, a plurality of first communicating holes 121aa are formed to allow the inside of the crown plate 121 and the collection manifold chamber 111e to communicate with each other. Each of the first communicating holes 121aa is formed to be located at the same height as the lower inner surface of the horizontal plate 121a. In each of the upper surfaces of the tilted plates 121b of the crown plate 121, a plurality of second communicating holes 121ba are formed to allow the inside of the crown plate 121 and the collection manifold chamber 111e to communicate with each other. The above-described first and second communicating holes 121aa and 121ba constitute communicating holes in this embodiment.

It should be noted that in the drawings, 122 denotes partition plates for separating the steam receiving chamber 111a from the moisture separation chambers 111c and the heating chambers 111d, 123 denotes partition plates for separating the supply manifold chambers 111b from the heating chambers 111d, and 124 denotes tilted plates for separating the supply manifold chambers 111b from the collection manifold chamber 111e.

Next, the operation of the above-described moisture separator reheater 100 according to this embodiment will be described.

When the steam 1 discharged from the high-pressure steam turbine is fed through the steam receiving openings 112a and 112b to the steam receiving chamber 111a in the shell body 111, the steam 1 is guided while an impact thereof is alleviated by the baffle plate 113, and flows into the supply manifold chamber 111b.

The steam 1 which has flowed into the supply manifold chamber 111b passes through the slits 114a of the distributor plates 114 to circulate through the mist separators 115 in the moisture separation chambers 111c, thus undergoing moisture separation, and thereafter flows into the heating chambers 111d.

The steam 1 which has flowed into the heating chambers 111d comes in contact with the first-stage heater tube groups 116 to be heated by the steam 2 for heating which has entered the first-stage heater tube groups 116 through the steam supply openings 118c of the first-stage heater steam chambers 118, passes through the distributing chambers 118a, and circulates in the first-stage heater tube groups 116. Then, the steam 1 comes in contact with the second-stage heater tube groups 117 to be further heated by the steam 3 for heating which has entered the second-stage heater tube groups 117 through the steam supply openings 119c of second-stage heater steam chambers 119, passes through the distributing chambers 119a, and circulates in the second-stage heater tube groups 117. Thereafter, the steam 1 flows into the collection manifold chamber 111e.

The steam 1 which has flowed into the collection manifold chamber ille circulates in the collection manifold chamber ille, and is sent out from the steam delivery openings 120a to 120c to be fed to the low-pressure steam turbines, respectively.

A very small portion of the steam 1 circulating in the collection manifold chamber ille enters the inside of the crown plate 121 through the communicating holes 121aa and 121ba of the crown plate 121 to form a heat insulating layer. Thus, the crown plate 121 can greatly reduce the heat conduction between the adjacent sections respectively of the steam receiving chamber 111a and the collection manifold chamber 111e.

Accordingly, the temperature of the steam 1 sent out from the steam delivery opening 120a which is located above the crown plate 121 in the axially central portion of the shell body 111, i.e., which is connected to a space part adjacent to the steam receiving chamber 111a, can be prevented from decreasing to below the temperature of the steam 1 sent out from the steam delivery openings 120b and 120c located on the two axial end sides of the shell body 111.

Thus, the moisture separator reheater 100 according to this embodiment makes it possible to prevent a decrease in temperature of the steam 1 sent out from the steam delivery opening 120a, and therefore makes it possible to prevent a decrease in thermal efficiency of the low-pressure steam turbine fed with the steam 1 from the steam delivery opening 120a.

Moreover, since the first communicating holes 121aa of the crown plate 121 are formed to be located at the same height as the lower inner surface of the horizontal plate 121a, even if a decrease in temperature due to a stoppage of the operation produces a drain inside the crown plate 121, the drain flows to the outside through the first communicating holes 121aa. Accordingly, the drain can be prevented from being trapped in the crown plate 121.

Moreover, since the second communicating holes 121ba of the crown plate 121 are formed in the upper surfaces of the tilted plates 121b, even in the event of a slight drain being trapped in the crown plate 121 and vaporizing as temperature increases due to a resumption of the operation, the drain flows to the outside through the second communicating holes 121ba. Accordingly, the dilation deformation of the crown plate 121 can be prevented.

Second Embodiment

Hereinafter, a second embodiment of a moisture separator reheater according to the present invention will be described with reference to FIGS. 6 to 8. FIG. 6 is a view schematically showing the configuration of the moisture separator reheater and showing a cross section containing the central axis thereof. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 as seen in the direction of arrows VII. FIG. 8 is a schematic diagram showing the configuration of a crown plate in FIGS. 6 and 7. It should be noted that components similar to those of the above-described first embodiment are denoted by reference numerals similar to those used in the description of the above-described first embodiment, and the same descriptions as the corresponding descriptions of the above-described first embodiment are not repeated here.

As shown in FIGS. 6 to 8, the adjacent sections respectively of the steam receiving chamber 111a in the shell body 111 and the collection manifold chamber 111e are partitioned by a crown plate 221. The crown plate 221 is a partition member, and serves as heat-conduction reducing means. The crown plate 221 includes a horizontal plate 221a and a tilted plate 221b which is on each of two sides of the horizontal plate 221a with respect to the radial direction of the shell body 111 so that outer portions of the shell body 111 with respect to the radial direction thereof may be located upward. In this crown plate 221, a heat insulating layer 221c is provided which is made of heat insulating material such as glass wool, felt, or the like.

In a moisture separator reheater 200 according to this embodiment which includes the above-described crown plate 221, as in the aforementioned first embodiment, the steam 1 discharged from the high-pressure steam turbine can be fed to the low-pressure steam turbines through the steam delivery openings 120a to 120c, respectively, after being fed to the inside of the shell body 111 through the steam receiving opening 112a and 112b to undergo moisture separation in the mist separators 115 of the moisture separation chambers 111c and then being heated by the heater tube groups 116 and 117 of the heating chambers 111d.

The adjacent sections respectively of the steam receiving chamber 111a in the shell body 111 and the collection manifold chamber 111e are partitioned by the crown plate 221 having the heat insulating layer 221c therein. Thus, the crown plate 221 can greatly reduce the heat conduction between the adjacent sections respectively of the steam receiving chamber 111a and the collection manifold chamber 111e.

Accordingly, the temperature of the steam 1 sent out from the steam delivery opening 120a which is located above the crown plate 221 in the axially central portion of the shell body 111, i.e., which is connected to a space part adjacent to the steam receiving chamber 111a, can be prevented from decreasing to below the temperature of the steam 1 sent out from the steam delivery openings 120b and 120c located on the two axial end sides of the shell body 11.

Thus, as in the aforementioned first embodiment, the moisture separator reheater 200 according to this embodiment makes it possible to prevent a decrease in temperature of the steam 1 sent out from the steam delivery opening 120a, and therefore makes it possible to prevent a decrease in thermal efficiency of the low-pressure steam turbine fed with the steam 1 from the steam delivery opening 120a.

It should be noted that, in this embodiment, a description has been made on a case where the crown plate 221 having provided therein the heat insulating layer 221c made of heat insulating material is employed; however, in other embodiments, it is possible to employ, for example, a crown plate having provided therein a heat insulating layer formed by a hollow air space part, a crown plate having a vacuum heat insulating layer provided therein, or the like.

Third Embodiment

Hereinafter, a third embodiment of a moisture separator reheater according to the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a view schematically showing the configuration of the moisture separator reheater and showing a cross section containing the central axis thereof. FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9 as seen in the direction of arrows X. It should be noted that components similar to those of the aforementioned first and second embodiments are denoted by reference numerals similar to those used in the description of the aforementioned first and second embodiments, and the same descriptions as the corresponding descriptions of the aforementioned first and second embodiments are not repeated here.

As shown in FIGS. 9 and 10, the respective sections of the steam receiving chamber 111a in the shell body 111 and the collection manifold chamber 111e are separated by a crown plate 321. The crown plate 321 includes a horizontal plate 321a and a tilted plate 321b which is on each of two sides of the horizontal plate 321a with respect to the radial direction of the shell body 111 so that outer portions thereof with respect to the radial direction of the shell body 111 may be located upward. The crown plate 321 has a configuration similar to that of the crown plate 21 of the conventional moisture separator reheater.

In a near-center portion of an upper portion of the shell body ill, a steam delivery opening 320a which communicates with the collection manifold chamber 111e to send out the steam 1 to a low-pressure steam turbine is provided in a region other than a part over the crown plate 321.

In other words, in the moisture separator reheater 300 according to this embodiment, the steam delivery openings 120b, 120c, and 320a are connected only to a space part in the collection manifold chamber 111e other than a space part therein adjacent to the steam receiving chamber 111a.

In the moisture separator reheater 300 according to this embodiment which includes the above-described steam delivery openings 120b, 120c, and 320a, as in the aforementioned first and second embodiments, the steam 1 discharged from the high-pressure steam turbine can be fed to the low-pressure steam turbines through the steam delivery openings 320a, 120b, and 120c, respectively, after being fed to the inside of the shell body 111 through the steam receiving opening 112a and 112b to undergo moisture separation in the mist separators 115 of the moisture separation chambers 111c and then being heated by the heater tube groups 116 and 117 of the heating chambers 111d.

The steam delivery opening 320a located near the axial center of the shell body 111 is provided in a region other than a part over the crown plate 321. In other words, the steam delivery openings 120b, 120c, and 320a are connected only to a space part in the collection manifold chamber 111e other than a space part therein adjacent to the steam receiving chamber 111a. Accordingly, the velocity of the steam 1 is very low in a part of the collection manifold chamber 111e which is located over the crown plate 321, i.e., in a space part in the collection manifold chamber 111e which is adjacent to the steam receiving chamber 111a. Thus, the heat conduction between the steam receiving chamber 111a and the collection manifold chamber 111e can be greatly reduced.

Accordingly, the temperature of the steam 1 sent out from the steam delivery opening 320a of the shell body ill can be prevented from decreasing to below the temperature of the steam 1 sent out from the steam delivery openings 120b and 120c located on the two axial end sides of the shell body 111.

Thus, as in the aforementioned first and second embodiments, the moisture separator reheater 300 according to this embodiment makes it possible to prevent a decrease in temperature of the steam 1 sent out from the steam delivery opening 320a, and therefore makes it possible to prevent a decrease in thermal efficiency of the low-pressure steam turbine fed with the steam 1 from the steam delivery opening 320a.

INDUSTRIAL APPLICABILITY

A moisture separator reheater according to the present invention can prevent a decrease in temperature of steam sent out from a steam delivery opening, and therefore can be used in a nuclear power plant or the like extremely effectively.

MOISTURE SEPARATOR REHEATER

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