Heat supply reform system and method of main steam extraction small machine under deep peak regulation working condition

Abstract

The application provides a heat supply transformation system and method of a main steam extraction small turbine under a deep peak regulation condition, which comprises a main steam pipeline unit, a steam extraction small turbine steam inlet pipeline unit and a main steam temperature and pressure reducing steam extraction small turbine pipeline unit, wherein the main steam temperature and pressure reducing steam extraction small turbine pipeline unit comprises a first main steam extraction temperature and pressure reducing branch pipe and a second main steam extraction temperature and pressure reducing branch pipe which are in communication with each other, and a main steam extraction temperature and pressure reducing main pipe which is in communication with the first main steam extraction temperature and pressure reducing branch pipe and the second main steam extraction temperature and pressure reducing branch pipe and is sequentially provided with a temperature and pressure reducing device, a second electric gate valve, a first electric gate valve and a first check valve; the temperature and pressure reducing device is connected with a temperature and pressure reducing valve rear steam extraction small turbine pipeline and a temperature reducing water pipeline; and the temperature and pressure reducing valve rear steam extraction small turbine pipeline is in communication with the steam extraction small turbine steam inlet pipeline unit. The application can ensure normal operation of the steam extraction small turbine, utilize the steam extraction small turbine exhaust steam for external heat supply, and solve the problems of insufficient heat supply and low heat supply parameters of the unit under the deep peak regulation condition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power plant heat engine, and particularly relates to a heat supply reconstruction system of main steam exhaust induced small machine under deep peak regulation condition. BACKGROUND

[0002] Clean and efficient utilization of coal is an important part of deepening the energy revolution. Under the "double carbon" goal, vigorously promoting the "three linkage" of energy saving and carbon reduction reconstruction, flexibility reconstruction, and heat supply reconstruction of coal-fired power plants is a key step to play the bottom-up guarantee role of the coal-fired power plant industry and continuously improve the level of clean and efficient development. If the "three linkage" of coal-fired power plants is implemented properly, it will greatly help the construction of a new power system and promote the clean and low-carbon transformation of energy.

[0003] Generally, the electrical load and the thermal load of the unit are in a strong coupling relationship. When the unit generates power, the amount of heat supplied to the outside also increases. Under 50% THA condition, the unit's heat supply capacity decreases. And when the unit is peak-regulated to below 50% load, the current exhaust steam, secondary cooling, and secondary heating parameters are all below 1.5 MPa, and the steam parameters cannot meet the needs of the heat users. The current conventional method is to extract steam from the primary low-temperature reheated steam pipeline and reduce the temperature and pressure to directly supply heat to the outside, but this scheme will cause a loss of high-grade work enthalpy, and the steam-induced draft fan small machine is bypassed and stopped, which on the one hand will cause a significant increase in plant power consumption, and on the other hand, the start-up exhaust loss of the steam-induced small machine will occur. SUMMARY

[0004] The purpose of the present application is to provide a heat supply reconstruction system of main steam temperature and pressure reducing exhaust induced small machine under deep peak regulation condition, which can switch the steam inlet of the steam-induced small machine from the intermediate outlet of the cold reheater (steam-induced small machine inlet pipeline unit) to the main steam temperature and pressure reducing pipeline under the condition of unit below 50% THA, which can not only ensure the normal operation of the steam-induced small machine, but also utilize the steam-induced small machine exhaust to supply heat to the outside, solve the problem of insufficient heat supply and low heat supply parameters of the unit under deep peak regulation condition, realize the decoupling of the electrical and thermal loads of the unit, meet the dual needs of the power grid and the heat users, realize the mutual independence of the power generation load and the heat supply load of the thermal power unit, and meet the conditions for the unit to participate in deep flexible peak regulation.

[0005] A heat supply reconstruction system of main steam temperature and pressure reducing exhaust induced small machine under deep peak regulation condition, comprising:

[0006] a main steam pipeline unit and a steam-induced small machine inlet pipeline unit;

[0007] and a main steam temperature and pressure reducing exhaust induced small machine pipeline unit, which is arranged between the main steam pipeline unit and the steam-induced small machine inlet pipeline unit, and comprises:

[0008] The first main steam extraction temperature and pressure reducing branch pipe 200 and the second main steam extraction temperature and pressure reducing branch pipe 210 are arranged between the two boiler superheater outlet headers and are communicated with each other;

[0009] The main steam extraction temperature and pressure reducing main pipe 220 is communicated with the first main steam extraction temperature and pressure reducing branch pipe 200 and the second main steam extraction temperature and pressure reducing branch pipe 210, and a temperature and pressure reducing device 224, a second electric gate valve 223, a first electric gate valve 222 and a first check valve 221 are sequentially arranged on the main steam extraction temperature and pressure reducing main pipe 220;

[0010] The first check valve 221 is arranged close to the first main steam extraction temperature and pressure reducing branch pipe 200 and the second main steam extraction temperature and pressure reducing branch pipe 210;

[0011] The temperature and pressure reducing device 224 is connected with a temperature and pressure reducing valve rear steam extraction small machine pipe 240 and a temperature reducing water pipe 230;

[0012] The temperature and pressure reducing valve rear steam extraction small machine pipe 240 is communicated with a steam extraction small machine steam inlet pipe unit;

[0013] An output end of the temperature reducing water pipe 230 is connected with the temperature and pressure reducing device 224.

[0014] Preferably, a flow meter 241 and a third electric gate valve 242 are sequentially arranged on the temperature and pressure reducing valve rear steam extraction small machine pipe 240, and the flow meter 241 is arranged close to the temperature and pressure reducing device 224.

[0015] Preferably, a first stop valve 231, a filter screen 232, an electric stop valve 233, an electric regulating valve 234, a second stop valve 235 and a second check valve 236 are sequentially arranged on the temperature reducing water pipe 230.

[0016] Preferably, the steam extraction small machine steam inlet pipe unit comprises:

[0017] A third steam extraction small machine steam inlet pipe 320;

[0018] A second steam extraction small machine steam inlet pipe 310 and a first steam extraction small machine steam inlet pipe 300, both of which are communicated with an output end of the third steam extraction small machine steam inlet pipe 320;

[0019] A fourth steam extraction small machine steam inlet pipe 330 and a fifth steam extraction small machine steam inlet pipe 340, both of which are communicated with an input end of the third steam extraction small machine steam inlet pipe 320.

[0020] Preferably, the fourth steam extraction small machine steam inlet pipe 330 is connected with a B30 induced draft fan small machine, and the fifth steam extraction small machine steam inlet pipe 340 is connected with an A20 induced draft fan small machine.

[0021] Preferably, the main steam pipe unit comprises:

[0022] The first main steam pipeline 100 is communicated with the first main steam extraction temperature and pressure reducing branch pipe 200.

[0023] The second main steam pipeline 110 is communicated with the second main steam extraction temperature and pressure reducing branch pipe 210.

[0024] The third main steam pipeline 120 is communicated with the high-pressure cylinder 10 through the first main steam pipeline 100;

[0025] The fourth main steam pipeline 130 is communicated with the super-high-pressure cylinder 10 through the second main steam pipeline 110.

[0026] Preferably, the main steam temperature and pressure reducing steam extraction turbine pipeline unit is started and put into use under the condition of 50% THA of the unit.

[0027] A heat supply reconstruction method of a main steam temperature and pressure reducing steam extraction turbine under a deep peak regulation condition, comprising the step of switching the steam extraction turbine from the intermediate outlet of the steam extraction turbine inlet pipeline unit to the main steam temperature and pressure reducing pipeline, specifically comprising:

[0028] Step one, start the first electric gate valve 222 and the second electric gate valve 223, and synchronously start the third electric gate valve 242, and then start the electric stop valve 233 after being in place;

[0029] Step two, after each valve is in place, open the electric regulating valve 234 and set the opening degree to a certain value, and set the opening degree of the pressure regulating valve of the temperature and pressure reducing device to a certain value;

[0030] Step three, close the first low-temperature reheated steam extraction turbine electric gate valve one 301 and the first low-temperature reheated steam extraction turbine electric gate valve two 311, and switch the steam extraction inlet to the main steam temperature and pressure reducing steam;

[0031] Step four, set the pressure regulating valve of the temperature and pressure reducing device 224 to automatic, and track the outlet pressure of the temperature and pressure reducing device 224; set the electric regulating valve 234 to automatic, and track the outlet temperature of the temperature and pressure reducing device 224.

[0032] Compared with the prior art, the application has the following advantages:

[0033] 1. Avoiding the enthalpy loss caused by directly supplying high-grade steam after temperature and pressure reduction to the outside;

[0034] 2. Under the condition of less than 50% THA of the unit, switching the steam extraction turbine inlet from the intermediate outlet of a cold reheater to the main steam temperature and pressure reducing pipeline, which can ensure the normal operation of the steam extraction turbine, utilize the steam extraction turbine exhaust steam to supply heat to the outside, solve the problems of insufficient heat supply and low heat supply parameters of the unit under the deep peak regulation condition, and realize the decoupling of the electric and thermal loads of the unit.

[0035] 3. Since the steam turbine can still run normally under the deep regulation condition, on the one hand, the auxiliary power consumption can be reduced, and on the other hand, the loss of start-up exhaust steam can be avoided when the steam turbine is restarted after shutdown, thereby reducing the working medium loss;

[0036] 4. The frequent start-stop of the steam turbine under low load due to grid peak regulation is avoided, and the stability and safety of the steam turbine system operation are improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 Fig. 1 is a schematic diagram of a heat supply system for a main steam temperature and pressure reducing steam turbine under deep peak regulation conditions;

[0038] Figure 2 Fig. 2 is a structural diagram of a main steam temperature and pressure reducing steam turbine pipeline unit;

[0039] Figure 3 Fig. 3 is a structural diagram of a steam turbine inlet pipeline unit;

[0040] Figure 4 Fig. 4 is a structural diagram of a main steam pipeline unit.

[0041] 100 - first main steam pipeline, 110 - second main steam pipeline, 120 - third main steam pipeline, 130 - fourth main steam pipeline,

[0042] 200 - first main steam extraction temperature and pressure reducing branch pipe, 210 - second main steam extraction temperature and pressure reducing branch pipe,

[0043] 220 - main steam extraction temperature and pressure reducing main pipe, 221 - first check valve, 222 - first electric gate valve, 223 - second electric gate valve, 224 - temperature and pressure reducer,

[0044] 230 - temperature reducing water pipeline, 231 - first stop valve, 232 - filter screen, 233 - electric stop valve, 234 - electric regulating valve, 235 - second stop valve, 236 - second check valve,

[0045] 240 - temperature and pressure reducing valve after steam turbine pipeline, 241 - flow meter, 242 - third electric gate valve, 243 - safety valve;

[0046] 300 - first steam turbine inlet pipeline, 310 - second steam turbine inlet pipeline, 320 - third steam turbine inlet pipeline, 340 - fifth steam turbine inlet pipeline,

[0047] 10 - high-pressure cylinder, 20 - induced draft fan turbine A, 30 - induced draft fan turbine B,

[0048] 301 - first low-temperature reheat steam extraction small machine electrically operated gate valve, 311 - second low-temperature reheat steam extraction small machine electrically operated gate valve, 331 - flow measuring device one;

[0049] 332 - third low-temperature reheat steam extraction small machine electrically operated gate valve, 342 - fourth low-temperature reheat steam extraction small machine electrically operated gate valve, 341 - flow measuring device two;

[0050] 302 - third check valve, 312 - fourth check valve. Embodiment

[0051] The main steam temperature and pressure reducing steam extraction small machine heat supply modification system under deep peak regulation conditions will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the present application is shown, and it should be understood that the present application described herein can be modified by those skilled in the art, while still achieving the advantageous effects of the present application. Therefore, the following description should be understood as extensive knowledge for those skilled in the art, and not as a limitation on the present application.

[0052] As Figures 1-4 The main steam temperature and pressure reducing steam extraction small machine heat supply modification system under deep peak regulation conditions adopts the technical scheme of main steam temperature and pressure reducing to the steam extraction small machine, realizes the thermal and electrical decoupling of the unit, and ensures stable heat supply to the outside when the unit is under 50% THA condition. Through the unit heat supply modification scheme, it is ensured that the steam extraction small machine can stably operate and supply heat to the outside through exhaust steam when the unit is under deep peak regulation, which ensures the stability of the heat network. At the same time, the stable operation of the steam extraction small machine is conducive to reducing the auxiliary power rate during deep regulation and improving the economic benefits of the whole plant.

[0053] THA condition: heat rate acceptance condition, the steam turbine is under rated admission parameters, rated back pressure, normal operation of the regenerative system, 0% make-up water rate, and can continuously generate power. 50% THA condition means that the unit operates at 50% of the power generated under the heat rate acceptance condition.

[0054] The heat supply modification system comprises a main steam pipeline unit, a steam extraction small machine admission pipeline unit, and a main steam temperature and pressure reducing steam extraction small machine pipeline unit.

[0055] The main steam pipeline unit, as shown in Figure 4 , comprises:

[0056] A first main steam pipeline 100 is in communication with a first main steam extraction temperature and pressure reducing branch pipe 200;

[0057] A second main steam pipeline 110 is in communication with a second main steam extraction temperature and pressure reducing branch pipe 210;

[0058] The third main steam pipeline 120 is connected to one end of the high-pressure cylinder 10 and communicates with the high-pressure cylinder 10.

[0059] The fourth main steam pipeline 130 is connected to one end of the super-high-pressure cylinder 10 and communicates with the super-high-pressure cylinder 10.

[0060] As shown in the figure, the steam turbine inlet pipeline unit comprises: Figure 3 The third steam turbine inlet pipeline 320;

[0061] The second steam turbine inlet pipeline 310 and the first steam turbine inlet pipeline 300 both communicate with the output end of the third steam turbine inlet pipeline 320;

[0062] The fourth steam turbine inlet pipeline 330 and the fifth steam turbine inlet pipeline 340 both communicate with the input end of the third steam turbine inlet pipeline 320.

[0063] The fourth steam turbine inlet pipeline 330 is connected to the induced draft fan turbine B30, and the fifth steam turbine inlet pipeline 340 is connected to the induced draft fan turbine A20.

[0064] The steam turbine inlet pipeline unit further comprises: a first low-temperature reheated steam to steam turbine electrically-operated gate valve one 301, a first low-temperature reheated steam to steam turbine electrically-operated gate valve two 311, a first low-temperature reheated steam to steam turbine electrically-operated gate valve three 332, a first low-temperature reheated steam to steam turbine electrically-operated gate valve four 342, a third check valve 302, a fourth check valve 312, a flow measuring device one 331 and a flow measuring device two 341.

[0065] The main steam temperature and pressure reducing to steam turbine pipeline unit is arranged between the main steam pipeline unit and the steam turbine inlet pipeline unit and is started and put into use under the 50% THA working condition of the unit.

[0066] As shown in the figure, the main steam temperature and pressure reducing to steam turbine pipeline unit comprises:

[0067] Figure 2 The first main steam extraction temperature and pressure reducing branch pipeline 200 and the second main steam extraction temperature and pressure reducing branch pipeline 210 are arranged between the two boiler superheater outlet headers and communicate with each other;

[0068] The main steam extraction temperature and pressure reducing main pipeline 220 communicates the first main steam extraction temperature and pressure reducing branch pipeline 200 and the second main steam extraction temperature and pressure reducing branch pipeline 210, and a temperature and pressure reducer 224, a second electrically-operated gate valve 223, a first electrically-operated gate valve 222 and a first check valve 221 are sequentially arranged on the main steam extraction temperature and pressure reducing main pipeline 220.

[0069] The main steam extraction temperature and pressure reducing main pipeline 220 communicates the first main steam extraction temperature and pressure reducing branch pipeline 200 and the second main steam extraction temperature and pressure reducing branch pipeline 210, and a temperature and pressure reducer 224, a second electrically-operated gate valve 223, a first electrically-operated gate valve 222 and a first check valve 221 are sequentially arranged on the main steam extraction temperature and pressure reducing main pipeline 220.

[0070] ​The check valve 221 is arranged close to the first main steam extraction temperature and pressure reducing branch pipe 200 and the second main steam extraction temperature and pressure reducing branch pipe 210.

[0071] The temperature and pressure reducing valve 224 is connected with the steam extraction small turbine pipe 240 and the temperature reducing water pipe 230.

[0072] The temperature and pressure reducing valve 224 is connected with the steam extraction small turbine pipe 240 and the temperature reducing water pipe 230.

[0073] The temperature and pressure reducing valve 224 is connected with the steam extraction small turbine pipe 240 and the temperature reducing water pipe 230.

[0074] The temperature and pressure reducing valve 224 is connected with the steam extraction small turbine pipe 240 and the temperature reducing water pipe 230.

[0075] The temperature and pressure reducing valve 224 is connected with the steam extraction small turbine pipe 240 and the temperature reducing water pipe 230.

[0076] In the embodiment, the main steam temperature and pressure reducing steam extraction small turbine pipe system is started and put into use at 40% THA of the unit, the maximum steam extraction amount of the main steam is 71.9 t / h, and the maximum heat supply amount is 75 t / h.

[0077] In the embodiment, the main steam parameter is 15.226 MPa and 600 DEG C, the steam extraction small turbine steam inlet steam parameter after temperature and pressure reduction is 11.384 MPa and 540 DEG C.

[0078] In the embodiment, the steam extraction small turbine exhaust steam parameter is 1.5 MPa and 350 DEG C, which meets the heat supply parameter requirement.

[0079] The main steam temperature and pressure reducing steam extraction small turbine heat supply transformation system is applied to the unit under 40% THA working condition, and includes the following steps.

[0080] Step one, the first electric gate valve 222 and the second electric gate valve 223 of the main steam extraction temperature and pressure reducing pipe are started, the third electric gate valve 242 is started synchronously, the electric stop valve 233 is started after being in place;

[0081] Step two, in the step one, after the valves are in place, the electric regulating valve 234 is opened and the opening degree is set to a certain value, the temperature and pressure reducing device pressure regulating valve opening degree is set to a certain value;

[0082] Step three, the first low-temperature reheated steam extraction small turbine electric gate valve 301 and the second low-temperature reheated steam extraction small turbine electric gate valve 311 are closed, and the steam extraction steam inlet is switched to the main steam temperature and pressure reducing steam.

[0083] Step four, the pressure regulating valve of the desuperheater is set to automatic, tracking the outlet pressure of the desuperheater. The electric regulating valve of the desuperheater is set to automatic, tracking the outlet temperature of the desuperheater.

[0084] The above merely describes the preferred embodiments of the present application and does not limit the present application in any way. Any person skilled in the art, without departing from the scope of the technical solutions of the present application, can make any form of equivalent replacement or modification of the disclosed technical solutions and technical contents, and such changes still belong to the protection scope of the present application.

Claims

1. A heat supply reconstruction system of a main steam extraction small machine in a deep peak regulation mode, characterized in that, The utility model relates to a kind of steam turbine unit and its control method, including: Main steam pipeline unit and steam turbine unit steam inlet pipeline unit; And main steam temperature and pressure reducing steam turbine unit, main steam temperature and pressure reducing steam turbine unit is started under the condition of 50%THA of unit and is used, it is arranged between main steam pipeline unit and steam turbine unit steam inlet pipeline unit, it includes: No. 1 main steam extraction temperature and pressure reducing branch pipe (200) and no. 2 main steam extraction temperature and pressure reducing branch pipe (210), it is arranged between the two boiler superheater outlet header, and intercommunication is communicated; Main steam extraction temperature and pressure reducing main pipe (220), communicate no. 1 main steam extraction temperature and pressure reducing branch pipe (200) and no. 2 main steam extraction temperature and pressure reducing branch pipe (210), it is sequentially provided with temperature and pressure reducing device (224), no. 2 electric gate valve (223), no. 1 electric gate valve (222), no. 1 check valve (221) on it; Wherein, the no. 1 check valve (221) is close to no. 1 main steam extraction temperature and pressure reducing branch pipe (200) and no. 2 main steam extraction temperature and pressure reducing branch pipe (210) setting; The temperature and pressure reducing device (224) is connected with temperature and pressure reducing valve after steam turbine unit pipeline (240) and temperature and pressure reducing water pipeline (230); The temperature and pressure reducing valve after steam turbine unit pipeline (240) is communicated with steam turbine unit steam inlet pipeline unit; The output end of the temperature and pressure reducing water pipeline (230) is connected with temperature and pressure reducing device (224); The steam turbine unit steam inlet pipeline unit includes: No. 3 steam turbine unit steam inlet pipeline (320); No. 2 steam turbine unit steam inlet pipeline (310) and no. 1 steam turbine unit steam inlet pipeline (300), both are communicated with the output end of no. 3 steam turbine unit steam inlet pipeline (320); No. 4 steam turbine unit steam inlet pipeline (330) and no. 5 steam turbine unit steam inlet pipeline (340), both are communicated with the input end of no. 3 steam turbine unit steam inlet pipeline (320); The main steam pipeline unit includes: No. 1 main steam pipeline (100) is communicated with no. 1 main steam extraction temperature and pressure reducing branch pipe (200); No. 2 main steam pipeline (110) is communicated with no. 2 main steam extraction temperature and pressure reducing branch pipe (210); No. 3 main steam pipeline (120), no. 1 main steam pipeline (100) is connected with the one section of high pressure cylinder (10), and is communicated with it; No. 4 main steam pipeline (130), no. 2 main steam pipeline (110) is connected with the one section of superhigh pressure cylinder (10), and is communicated with it. Flowmeter (241) is sequentially arranged on the temperature and pressure reducing valve after steam turbine unit pipeline (240), and the flowmeter (241) is close to temperature and pressure reducing device (224) setting.

2. The heat supply reconstruction system of the small turbine for removing steam from the main steam in the deep peak regulation mode according to claim 1, characterized in that, Temperature and pressure reducing water pipeline (230) sequentially sets up no. 1 stop valve (231), filter screen (232), electric stop valve (233), electric regulating valve (234), no. 2 stop valve (235), no. 2 check valve (236).

3. The heat supply reconstruction system of the small turbine for removing steam from the main steam in the deep peak regulation mode according to claim 1, characterized in that, No. 4 steam turbine unit steam inlet pipeline (330) is connected with induced draft fan unit B (30), and no. 5 steam turbine unit steam inlet pipeline (340) is connected with induced draft fan unit A (20).

4. The heat supply reconstruction system of the small turbine for removing steam from the main steam in the deep peak regulation mode according to claim 1, characterized in that, Including the step of switching the steam inlet of steam turbine unit from the intermediate outlet of steam turbine unit steam inlet pipeline unit to main steam temperature and pressure reducing pipeline, specifically including:

5. A heat supply reforming method of a main steam extraction small turbine in a deep peak load operation, the heat supply reforming method being applied to the heat supply reforming system according to any one of claims 1 to 4, characterized in that, ​ Step one, start the first electric gate valve (222), the second electric gate valve (223), and the third electric gate valve (242) synchronously, and then start the electric stop valve (233) after reaching the position; Step two, after the valves reach the position, open the electric regulating valve (234) and set the opening to a certain value, and set the opening of the pressure regulating valve of the desuperheater to a certain value; Step three, close the first low-temperature reheated steam exhaust turbine electric gate valve one (301) and the first low-temperature reheated steam exhaust turbine electric gate valve two (311), and switch the steam admission to the main steam desuperheated steam; Step four, set the pressure regulating valve of the desuperheater (224) to automatic and track the outlet pressure of the desuperheater (224), and set the electric regulating valve (234) to automatic and track the outlet temperature of the desuperheater (224).

6. The heat supply transformation method of the main steam extraction turbine under the deep peak load operation condition according to claim 5, characterized in that, The maximum steam extraction amount of the main steam is 71.9 t / h, and the maximum heat supply amount is 75 t / h.

7. The heat supply transformation method of the small turbine for removing main steam in the deep peak regulation mode according to claim 5, characterized in that, The steam parameters of the desuperheated steam admission of the small steam turbine are 11.384 MPa and 540℃.

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