WO2015024886A1

WO2015024886A1 - Steam power plant and method for operating a steam power plant

Info

Publication number: WO2015024886A1
Application number: PCT/EP2014/067531
Authority: WO
Inventors: Carsten Graeber; Georg Haberberger; Michael Wechsung
Original assignee: Siemens Aktiengesellschaft
Priority date: 2013-08-22
Filing date: 2014-08-18
Publication date: 2015-02-26

Abstract

The invention relates to a steam power plant comprising at least one first partial turbine with a first turbine outlet line and a second partial turbine, each permeated by steam, the permeating steam expanding in a first and second expansion area, comprising several steps, of the partial turbines. In the expansion area and/or in the first turbine outlet line of the first partial turbine, a line (101, 201) is provided to bleed the steam. Said line leads to at least one control valve in an expansion line (102, 202) which is connected to a load (170, 270). Said line (101, 201) leads to the other control valve in a bypass line (103, 203) which is joined, at least in terms of flow, to the second expansion area of the second partial turbine such that the steam of the bypass line can run into the expansion area of the second partial turbine. The amount of steam respectively supplied can be adjusted. The invention also relates to a method for operating said type of steam power plant.

Description

description

Steam power plant and method for operating a steam power plant

The invention relates to a steam power plant, comprising at least a first turbine part with a first turbine outlet conduit and a second turbine part, each of which can be traversed by steam and whereby the steam flowing through in a first and second, comprising several stages expansion area of the turbine sections, wherein in the expansion area and / or in the first turbine outlet line of the first part turbine, a line is provided for a steam extraction. Furthermore, the invention comprises a method for operating such a steam power plant.

Especially in steam power plants with very high efficiency requirements is looking for suitable ways to decouple large amounts of steam suitable. Large quantities of steam are required, for example, for district heating extraction, for fuel treatment, in particular lignite drying, or for flue gas scrubbing, in particular a CO ₂ separation. These consumers, in addition to the large amounts of steam, which may be up to half of the steam supplied in a conventional steam power plant of a low pressure turbine section, the steam at a relatively low temperature level of 100 ° C to 150 ° C in the vicinity of the condensation temperature. By reducing the mass flow before the actual reheat, the connecting pipes and the Überhitzungsheizflächen in the boiler can be made significantly smaller. However, this leads to problems in special load cases such as load jumps due to primary control requirement or certain incidents in case of failure of the process steam consumers.

A first object of the invention is therefore to provide a steam power plant, in which large amounts of steam can be coupled, which avoids the above problems. Another object is the specification of a method for operating such a steam power plant.

According to the invention, the first object is achieved with the specification of a steam power plant, which comprises at least a first turbine part with a first turbine outlet line and a second turbine part, each of which can be traversed by steam and wherein the steam flowing in a first and second expansion stages comprising several stages of the partial turbines expands , In this case, a line to a Dampfentnähme is provided in the expansion area and / or in the first turbine outlet line of the first turbine part. According to the invention, the line opens at least on the one hand into an expansion line to which a consumer is connected. According to the invention, the line leads to the other in a bypass line, which is at least fluidically connected to the second expansion region of the second turbine part, so that the steam of the bypass line in the expansion region of the second turbine part is inflowed, wherein the respectively supplied amount of steam is adjustable.

Thus, in load cases, the excess steam of the line via the bypass line to the expansion region of the second turbine part, which is in particular a low-pressure turbine part, are supplied. With the invention, on the one hand a considerable potential for the provision of primary control power as well as a secured operation in the event of a fault can be ensured on the one hand due to the very high process steam intake during normal operation.

In addition, the line preferably flows fluidly into a bypass line which opens into an overflow line, wherein the overflow line is fluidically connected at least to the second partial turbine. Thus, at least partially, the steam of the line in an accident of the second turbine part, in particular to the input of the second turbine part, are supplied. Thus, large amount of steam can be safely removed in the line. In a preferred embodiment, the overflow is also fluidly connected to the first turbine part. In a preferred embodiment, at least the line, the bypass line and the expansion line at least one control valve for regulating the amount of steam flowing through. Thus, the amounts of steam that occur in a fault, on the different lines, be divided. This ensures safe operation.

In a preferred embodiment, the first turbine part is a medium-pressure turbine section, and the second turbine part is a low-pressure turbine section, wherein the medium-pressure turbine section has a first stage comprising a plurality of stages and a second stage comprising several stages. In this case, the first flood has a first flood outlet line and the second flood a second flood outlet line. In this case, the overflow line is fluidically connected to the second flood outlet line, and the first flood outlet line is connected to the line. In this case, the line terminates on the one hand in an expansion line, wherein in the expansion line a consumer is provided with an end user, and wherein the line to another opens into a bypass line, which is at least fluidically connected to the second expansion region of the low-pressure turbine section, so that the steam of the bypass line can be flowed into the expansion region of the low-pressure turbine section. The second flood outlet line is preferably connected to the overflow line.

In a preferred embodiment, a preheating line branches off from the bypass line. Thus, the extracted steam can also be used for preheating, in particular for preheating the condensate water. The second expansion area of the second sub-turbine preferably has a bleed line, wherein the bypass line opens into this bleed line. Thus, an inflow of steam, which is in the bypass line, in the expansion range of the second turbine part can be easily accomplished.

Preferably, the consumer comprises at least one expansion turbine, which is connected via a process steam line to an end user. Furthermore, the expansion turbine is also preferably connected to a generator.

Within the expansion turbine, the extracted steam is expanded to a desired level for the consumer while performing work. This can be accomplished, for example, by using a generator.

According to the invention, the second object is achieved by specifying a method for operating such a steam power plant, comprising at least a first turbine part with a first turbine outlet line and a second turbine part, each of which can be traversed by steam and whereby the steam flowing through in a first and second, expansion stage of the sub-turbines comprising several stages expands, wherein in the expansion area and / or in the first turbine outlet line of the first sub-turbine a line is provided to a Dampfentnähme which at least one consumer to be supplied with steam via an expansion line, in which the line opens at least can, and via a bypass line, in which the line opens to the other, at least the second expansion region of the second turbine part can be supplied with steam, wherein the respectively supplied amount of steam is adjustable.

By the proposed solution according to the invention, it is possible to remove a serious disadvantage for concepts with a cold expansion for a consumer with an end user. The feeding of the requested steam, or the resulting steam, from the cold expansion, can be carried out without additional design requirements for the reheat under Arbeitsverrichtung in the second part of the turbine.

In the following, embodiments of the invention will be explained in more detail with reference to a drawing. Showing:

1 shows schematically a steam power plant according to the prior

2 schematically shows a first example of a steam power plant with a number of sub-turbines,

3 schematically shows a second example of a steam power plant with a number of sub-turbines.

1 shows a steam power plant according to the prior art with a number of sub-turbines, which are designed for different pressures. The sub-turbines are assigned one behind the other to a common shaft 5. For operation, water is heated in a steam boiler 7 and steam is generated via a live steam superheater 9. The superheated steam is introduced as working steam via a piping in a high-pressure turbine section 13, where the steam is released. After expansion in the high-pressure turbine section 13, a portion of the steam is passed via a first reheat line 14 into a reheater 15 where it is reheated and then passed into a double-flow medium-pressure turbine section 17. Here, the steam expands again to a predetermined, now lower pressure level. Following this, the steam expanded in the medium-pressure turbine section 17 to the lower pressure level is conducted via a connected overflow line 21 into a likewise double-flow low-pressure turbine section 25. About the common shaft 5, a generator 29 is driven to generate electricity. The low pressure partial turbine 25 leaving, relaxed and cooled steam flows into a condenser 31, where he by heat transfer to the environment condenses and collects as liquid water. Via a condensate pump 33 and a preheater 35, the water is temporarily stored in a feedwater tank 37 and then fed via a feedwater pump 39 and a preheater 35 again to the steam boiler 7. The high-pressure turbine part 13 is connected to the expansion stage in the turbine outlet line 99, and in terms of flow before the reheater 15, a bleed line 41 according to the prior art. About this bleed line 41 according to the prior art, the system for the expansion of the high-pressure turbine section 13 of the required steam for a consumer 49 is removed (removal after the cold expansion).

The bleed line 41 according to the prior art opens into an expansion device 43 according to the prior art, which is thus connected to the high-pressure turbine section 13. The prior art expansion device 43 may be configured as a separate expansion turbine 44 to which a second generator 45 is connected. Within the expansion turbine 44, the extracted steam is ideally expanded to a desired level for the consumer 49 (pressure, temperature) while performing work for the entire system. From the expansion turbine 44, the relaxed process steam is passed on via a process steam line 47 directly to a consumer 49. This is designed for example as a fuel treatment or as a flue gas treatment. The separate expansion turbine 44 is used in counter-pressure operation. The expansion end corresponds as possible in this case directly to the required process steam pressure, so that the expansion turbine 44 provides the required pressure and temperature level for the connected load 49 in an ideal manner.

The reduction of the unnecessary superheated heat of the process steam therefore takes place according to the state of the art, in that the amount of steam required in each case before the intermediate overheating 15 is removed and expanded by a corresponding expansion device to the required pressure level of the process steam consumer under Arbeitsverrichtung. By reducing the mass flow before the actual reheat 15, the connecting pipes, ie the first reheat pipe 14 and the Überhitzungsheizflachen (not shown) in the boiler 7 can be made significantly smaller. However, this leads in special load cases such as load jumps because of a primary control requirement or certain incidents in case of failure of the process steam consumer problems, since then excess steam from the cold expansion, ie after relaxing in the turbine 13, not readily to a hot expansion, the is about the reheater 15, can be performed. In addition, in turbine concepts with asymmetric medium-pressure turbine sections (compare 44 in FIG. 3) in processes with double superheating 75, 15 (FIG. 3), problems arise with thrust balance within the medium-pressure turbine section 44 due to greatly varying mass and pressure conditions in the two Turbine floods 77,78 (FIG 3).

According to the invention, it is now proposed according to FIG. 2 that a line 101 is provided downstream of the expansion stage in the turbine outlet line 199 of the high-pressure turbine 13, which opens into an expansion line 102 to which a consumer 170 is connected. In this case, the consumer 170 includes an expansion turbine 144, which may also be connected to a generator 160. The expansion device is connected via a process steam line 147 to an end user 149. According to the invention, the line 101 leads to another in a bypass line 103, which opens into an expansion region of the low-pressure turbine section 25. Steam can now be led on the one hand to the consumer 170, on the other hand and in particular in the case of incidents, to the expansion area of the second low-pressure turbine part 25. The supplied amount of steam can be adjusted by control valves 100, so that a secure operation can be accomplished. In addition, the line 101 also opens into a bypass line 105, which is connected to the overflow line 21, which leads from the medium-pressure turbine section 17 in the low-pressure turbine section 25. In addition, a preheating line 150 branches off from the bypass line 103, which is here connected to one of the preheaters 35, for preheating the

Condensate water. In this case, the preheating line 150 is preferably connected to the preheater 35 after the condensate pump 33 (solid line). Alternatively / additionally, the preheating line 150 may also be connected to the preheater 35 in front of the boiler 7 (dashed line). The preheating line 105 may also be / alternatively connected to the feedwater tank 37 or other components of the steam power plant. Both the conduit 101, the bypass 105, the

Bypass line 103 as well as the expansion line 102 and the preheating line 150 have at least one control valve 100, for regulating the amount of steam flowing through.

Thus, in load cases, the excess steam of the line 101 via the bypass line 103 of the low pressure turbine part 25 can be supplied. In addition, according to the invention, the excess steam can be flowed into the overflow line 21 in front of the low-pressure part-turbine 25 via a bypass line 105 according to the invention. In addition, the excess steam can be used via a preheating 150 according to the invention for preheating the Kondesatwassers.

3 shows another example of a steam power plant according to the invention. The steam power plant is also designed here as a steam power plant with a number of sub-turbines. After expansion in the high-pressure turbine section 13, the working steam is conducted via a first reheat line 14 and via the first reheater 15 into the first single-flow medium-pressure turbine section 20 and expanded there. Via the second reheatening line 73, the expanded steam after the first medium-pressure sub-turbine 20 is passed through a second reheater 75. leads and led from there into a second medium-pressure turbine section 44.

The expansion turbine 44 assigned to the common shaft 5 is configured according to FIG. 3 as an asymmetric medium-pressure turbine section 44, which has a first expansion section, namely the first flow 77 and a second expansion section, namely the second flow 78. The second flood 78 is designed as a medium pressure turbine. After the expansion, the steam flows via a overflow line 210 into a double-flow low-pressure turbine section 25. In addition, the second flood 78 is connected on the input side to the second intermediate superheat line 73. In addition, the first medium-pressure turbine part 20 is connected by a cold expansion line 74 15 with the first flood 77.

The first trough 77 relaxes the steam into a turbine exhaust passage 299b while performing work for the entire system. According to the invention, it is now proposed according to FIG. 3 that a line 201 is provided after the expansion stage in the turbine outlet line 299b of the first flow 77 of the second medium-pressure turbine section 44. The expanded steam is supplied via the line 201 to the load 270 via an expansion line 202. As in FIG. 2, the consumer 270 comprises an expansion turbine 244, which may also be connected to a generator 260. The expansion turbine 244 is connected via a process steam line 247 to an end user 249. According to the invention, the line 201 leads to another in a bypass line 203, which opens into the expansion region of the low-pressure turbine section 25. In addition, according to the invention, the line 201 also flows into a bypass line 205, which is connected to the overflow line 210, which fluidically couples the second flow 78 to the low-pressure part-turbine 25. In addition, from the bypass line 203 still branches off a preheating line 250, which is also connected here to one of the preheater 35, for preheating the Condensate water. Again, the preheating line 250 is preferably connected to the preheater 35 after the condensate pump 33 (solid line). Alternatively / Additionally, the preheat line 250 may also be connected to the preheater 35 in front of the boiler 7 (dashed line). Of course, the preheat line 250 may additionally or alternatively be connected to the feed water tank 37 or other components

(Not shown) . Both the line 201, the bypass line 205, the bypass line 203 and the expansion line 202 and the preheating line 250 have at least one control valve 100, which regulates the amount of steam flowing through.

Thus, in load cases, the excess steam of the line 201 via the bypass line 203 of the low-pressure turbine section 25 can be supplied. In addition, according to the invention, the excess steam can be flowed into the overflow line 210 upstream of the low-pressure turbine section 25 via a bypass line 205 according to the invention. In addition, the excess steam can be used via a Vorwärmleitung 250 according to the invention for preheating the condensate water.

According to the invention is therefore in the occurrence of special load cases such as load jumps due to a primary control requirement or certain incidents in case of failure of the process steam consumer, then existing excess steam from the cold expansion, that is the steam from the line 201,101 not on the reheater 15th or 75, that is, about a hot expansion. Rather, the problem of excess steam from the cold expansion is achieved according to the invention by the excess is then at least partially fed directly into the expansion region of the existing low-pressure turbine section 25 via the bypass line 103, 203. In this case, the steam of the bypass line 103, 203 can be fed via so-called tapping nozzles (not shown) into the expansion area of the existing low-pressure turbine part 25. In addition, the steam behind the cold expansion via a preheating 150,250, which is fluidically connected to the bypass line 103, 203, be used for a preheater 35 for the load cases described above. Also, the excess steam of the line 201,101 via a line 101,201 connected to the bypass line 105, 205, directly into the overflow 21,210 before the low-pressure turbine part 25 and thus bypassed via the reheater 15,75 are flowed.

The proposed solution according to the invention succeeds in eliminating a serious disadvantage for concepts with a cold expansion for a consumer 270, 170 with an end user 249.149. The feeding of the requested steam, or vapor, e.g. in the event of failure of the desorber, from the cold expansion, can be done without additional design requirements for the reheater 15,75 or to the consumer 170,270 under Arbeitsverrichtung in the low-pressure turbine section 25. Thus, for example, in asymmetric medium-pressure turbine sections 44, the serious problems in the thrust design are limited. Thus, the full potential for increased primary control performance can be exploited. The connection of the

Line 201,101 to the low-pressure turbine part 25 provides an additional degree of freedom for the control of the turbines with each other, in particular for the regulation of the medium-pressure turbine section 17,44 in the power plant. Thus, for example, no throttling is necessary for dimming the mass flows of the reheaters 12, 75.

The steam turbines, and in particular the vane ring in steam power plants, are subject to building tolerances in their manufacture. If the flow cross-section and thus the actual swallowing capacity deviate from the quantity originally used in the design of the steam turbine, the absorption capacity of the steam turbine is too great or too small. With the solution according to the invention, a deviation of the construction tolerance and thus a deviation of the ability to swallow through the bypass line 103, 203 and a quantity of steam guided through this bypass line can now be solved. With the invention can now on the one hand due to the in Normal operation of very high Prozeßdampfentnähme provided considerable potential for the provision of primary control power, as well as a safe operation in case of failure are ensured.

Claims

claims

1. steam power plant, comprising at least a first turbine part with a first turbine outlet pipe and a second turbine part, each of which is traversed by steam and whereby the steam flowing through expands in a first and second multiple stages expansion area of the turbine parts,

wherein in the expansion area and / or in the first turbine outlet line of the first turbine part a line

(101,201) is provided for a Dampfentnähme

d a d u r c h e s e n c i n e s, d a s s

the line (101, 201) opens at least on the one hand into an expansion line (102, 202) to which a consumer (170, 270) is connected,

wherein the line (101,201) to another in a bypass line (103,203) opens, which is at least fluidically connected to the second expansion region of the second turbine part so that the steam of the bypass line (103,203) in the expansion region of the second turbine part is inflowed, wherein the respective supplied amount of steam is adjustable.

2. Steam power plant according to claim 1,

d a d u r c h e s e n c i n e s, d a s s

from the line (101,201) branches off a bypass line (105,205) which opens into an overflow line (21,210), wherein the overflow line (21,210) is at least fluidically connected to the second part of turbine.

3. Steam power plant according to claim 2,

d a d u r c h e s e n c i n e s, d a s s

the overflow (21,210) is also fluidly connected to the first turbine part.

4. Steam power plant according to one of the preceding claims, d a d u r c h e c e n e c e s e s, d a s s

at least the line (101, 201), the bypass line (103, 203) and the expansion line (102, 202) at least one control Valve (100), for controlling the amount of steam flowing through.

5. Steam power plant according to one of the preceding claims, d a d u r c h e c e n e c e n e, d a s s

the first part turbine is a high-pressure part turbine (13) and the second part turbine is a low-pressure part turbine (25).

6. Steam power plant according to one of the preceding claims 1- 4,

d a d u r c h e s e n c i n e s, d a s s

the first sub-turbine is a medium-pressure sub-turbine (44), and the second sub-turbine is a low-pressure sub-turbine (25), the medium-pressure sub-turbine (44) comprising a first stage (77) comprising a plurality of stages and a second stage (78 ), wherein the first flood (77) has a first flood outlet line (299b) and the second flood (78) has a second flood outlet line (299a), wherein the overflow line (210) is fluidically connected to the second flood outlet line (299a), wherein the first flood outlet line (299b) is connected to the line (201), wherein the line (201) opens into an expansion line (202), wherein a consumer (270) with an end user (249) is provided in the expansion line (202) .

wherein the line (201) to another in a bypass line (203) opens, which is at least fluidly connected to the second expansion region of the low-pressure turbine section (25), so that the steam of the bypass line in the expansion range of the low-pressure turbine part (25 ) is einströmbar.

7. Steam power plant according to claim 6,

d a d u r c h e s e n c i n e s, d a s s

the second flood outlet line (299a) is connected to the overflow line (210).

8. Steam power plant according to one of the preceding claims, characterized in that

from the bypass line (103,203) branches off a preheating line (150,250).

9. Steam power plant according to one of the preceding claims, d a d u r c h e c e n e c i n e t, d a s s

the second expansion area of the second sub-turbine has a bleed line, wherein the bypass line (103, 203) opens into this bleed line.

10. Steam power plant according to one of the preceding claims, d a d u r c h e c e n e c i n e t, d a s s

the consumer (170,270) comprises at least one expansion turbine (144,244), which via a process steam line

(147,247) is connected to an end user (149,249).

11. Steam power plant according to one of the preceding claims, d a d u r c h e c e n e c i n e t, d a s s

the expansion turbine (144, 244) is also connected to a generator (160, 260).

12. A method for operating a steam power plant comprising at least a first turbine part with a first turbine outlet and a second turbine part, each of

Steam can be flowed through and whereby the steam flowing through expands in a first and second multiple stages expansion area of the sub-turbines,

(101,201) is provided for a Dampfentnähme

d a d u r c h e s e n c i n e s, d a s s

on the one hand the steam can flow via an expansion line (102, 202) connected to the line (101, 202), to which a consumer (170, 270) is connected, and on the other hand the steam via a bypass line (103, 203) connected to the line (101, 201), at least in the with the

Bypass line (103,203) connected to the second expansion area the second sub-turbine can flow, the j eweils supplied amount of steam is adjustable.