Steam turbine adapting to full-load efficient operation and control method thereof

Abstract

The invention discloses a steam turbine adapting to full-load efficient operation and a control method thereof and belongs to the technical field of power generation. The invention aims to solve the problem that the existing steam turbine cannot meet the requirements of low load and high efficiency during operation. An electric end main steam valve and an electric end adjusting valve are connected in series; a steam inlet port of the electric end main steam valve is connected with a boiler main steam output pipeline through a steam guide pipeline; a steam outlet of the electric end regulating valve is communicated with a steam inlet of the electric end cylinder, and the electric end cylinder is further communicated with a boiler main steam output pipeline through a steam supplementing valve; the end adjusting main steam valve and the end adjusting valve are connected in series; a steam inlet of the end adjusting main steam valve is connected with a boiler main steam output pipeline through another steam guide pipeline; the rotor penetrates through the electric end cylinder and the end adjusting cylinder and is coaxially arranged with the electric end cylinder and the end adjusting cylinder; the controller controls opening and closing of the electric end adjusting valve, the adjusting end adjusting valve and the steam supplementing valve according to the load sum percentage of the steam turbine. The method is suitable for steam turbine power generation control.

Description

Technical Field

[0001] The invention belongs to the technical field of power generation. Background Art

[0002] At present, the high-parameter thermal power steam turbine design has a single flow channel design for high pressure, and the flow area is determined according to the rated operating parameters. When the load is rated or above, the main steam inlet pressure is maintained at the rated parameters. After the unit reduces the load, the main steam flow entering the high pressure decreases, the pressure in the high pressure flow decreases, the main steam pressure and the extraction pressure of the high pressure heater decrease accordingly, and the feed water temperature also decreases as the load decreases, thereby reducing the cycle efficiency of the unit. It is difficult for a steam turbine of this design to take into account both the requirements of low load and high efficiency in operation. Summary of the invention

[0003] The present invention aims to solve the problem that the existing steam turbine cannot take into account both low load and high efficiency requirements during operation, and now provides a steam turbine suitable for full load and high efficiency operation and a control method thereof.

[0004] The steam turbine adapted to full-load high-efficiency operation of the present invention comprises: an electric end main steam valve, an electric end regulating valve, a regulating end main steam valve, a regulating end regulating valve, a supplementary steam valve, a regulating end cylinder, an electric end cylinder, a rotor and a controller;

[0005] The electric end main steam valve and the electric end regulating valve are connected in series; the steam inlet port of the electric end main steam valve is connected to the main steam output pipeline of the boiler through a steam guide pipeline;

[0006] The steam outlet of the electric end regulating valve is connected to the steam inlet of the electric end cylinder, and the side wall of the electric end cylinder is also provided with a second steam inlet, and the second steam inlet is connected to the main steam output pipeline of the boiler through the supplementary steam valve;

[0007] The regulating end main steam valve and the regulating end regulating valve are connected in series; the steam inlet of the regulating end main steam valve is connected to the main steam output pipeline of the boiler through another steam guide pipeline;

[0008] The steam outlet of the regulating end regulating valve is connected to the steam inlet port of the regulating end cylinder. The steam inlet end of the regulating end cylinder is arranged opposite to the steam inlet end of the electric end cylinder, and a bridge steam seal is arranged between the two to perform steam sealing on the steam inlet end of the regulating end cylinder and the electric end cylinder.

[0009] The rotor penetrates the electric end cylinder and the regulating end cylinder and is coaxially arranged with the electric end cylinder and the regulating end cylinder;

[0010] The rotor body located in the electric end cylinder and the regulating end cylinder is fixed with flow blades; and the flow blades are axially symmetrical about the rotor axis;

[0011] The flow blades on the rotor body of the electric end cylinder are arranged in sections; a steam extraction pipeline is arranged between each section, and the steam is transmitted to the heater through the steam extraction pipeline;

[0012] The main steam valve at the power end and the main steam valve at the regulating end are normally open valves;

[0013] The controller controls the switching of the electric end regulating valve, the regulating end regulating valve and the steam supplement valve according to the total percentage of the steam turbine load.

[0014] Furthermore, in the present invention, a regulating end exhaust check valve and an electric end exhaust check valve are respectively provided at the steam outlet end of the regulating end cylinder and the steam outlet end of the electric end cylinder, which are respectively used to discharge the steam in the regulating end cylinder and the electric end cylinder to the boiler cold section reheater.

[0015] Furthermore, in the present invention, the heaters through which steam is transmitted via the steam extraction pipeline are respectively heater No. 0, heater No. 1 and heater No. 2.

[0016] Furthermore, in the present invention, a high exhaust ventilation valve is also provided at the steam outlet end of the regulating end cylinder.

[0017] A control method for a steam turbine adapted to full-load and efficient operation, the method being used to control the above-mentioned steam turbine adapted to full-load and efficient operation, specifically comprising:

[0018] Obtaining the total percentage of steam turbine load in real time, and when the total percentage of steam turbine load is lower than 50%, controlling the electric end regulating valve to be fully opened;

[0019] When the total percentage of the steam turbine load is in the range of 50% to 100%, the electric end regulating valve is controlled to be fully opened, and the regulating end regulating valve is gradually opened to be fully opened as the percentage of the steam turbine load increases;

[0020] When the total percentage of the steam turbine load is higher than 100%, the electric end regulating valve, the regulating end regulating valve and the supplementary steam valve are all controlled to open.

[0021] Furthermore, in the present invention, a high exhaust ventilation valve is also provided at the steam outlet end of the regulating end cylinder. When the total load percentage of the turbine is lower than 50%, the high exhaust ventilation valve is controlled to open to discharge the steam in the regulating end cylinder to the condenser.

[0022] The steam turbine and control method thereof of the present invention can effectively improve the main steam pressure and feed water temperature of the steam turbine operation, and significantly improve the cycle thermal efficiency of the steam turbine. The steam turbine unit can maintain high-efficiency operation within the full load range, especially solve the problem of efficiency reduction under low load, so that the low-load operation and high-efficiency operation of the steam turbine can be taken into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the steam turbine adapted to full-load and efficient operation according to the present invention;

[0024] Figure 2 The block diagram of the steam turbine control principle is to adapt to full load and efficient operation. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0026] Specific implementation method 1: Referring to FIG. Figure 1 and Figure 2 Specifically describing this embodiment, the steam turbine adapted to full-load high-efficiency operation described in this embodiment includes: an electric end main steam valve 1, an electric end regulating valve 2, a regulating end main steam valve 3, a regulating end regulating valve 4, a supplementary steam valve 5, a regulating end cylinder 7, an electric end cylinder 8, a rotor 11 and a controller 9;

[0027] The electric end main steam valve 1 and the electric end regulating valve 2 are connected in series; the steam inlet port of the electric end main steam valve 1 is connected to the main steam output pipeline of the boiler through a steam guide pipeline;

[0028] The steam outlet of the electric end regulating valve 2 is connected to the steam inlet of the electric end cylinder 8. The side wall of the electric end cylinder 8 is also provided with a second steam inlet, which is connected to the main steam output pipeline of the boiler through the supplementary steam valve 5.

[0029] The regulating end main steam valve 3 and the regulating end regulating valve 4 are connected in series; the steam inlet of the regulating end main steam valve 3 is connected to the main steam output pipeline of the boiler through another steam guide pipeline;

[0030] The steam outlet of the regulating end regulating valve 4 is connected to the steam inlet port of the regulating end cylinder 7. The steam inlet end of the regulating end cylinder 7 is arranged opposite to the steam inlet end of the electric end cylinder 8, and a bridge steam seal 6 is arranged between the two to seal the steam inlet end of the regulating end cylinder 7 and the electric end cylinder 8.

[0031] The rotor 11 penetrates the electric end cylinder 8 and the regulating end cylinder 7 and is coaxially arranged with the electric end cylinder 8 and the regulating end cylinder 7;

[0032] The rotor 11 is located in the electric end cylinder 8 and the regulating end cylinder 7. The flow blades are fixed on the body thereof. The flow blades are axially symmetrical with respect to the axis of the rotor 11.

[0033] The flow blades on the rotor 11 body of the electric end cylinder 8 are arranged in sections; a steam extraction pipeline is arranged between each section, and the steam is transmitted to the heater through the steam extraction pipeline;

[0034] The main steam valve 1 at the power end and the main steam valve 3 at the regulating end are normally open valves;

[0035] The controller 9 controls the switching of the electric end regulating valve 2, the regulating end regulating valve 4 and the supplementary steam valve 5 according to the total percentage of the turbine load.

[0036] Furthermore, in the present invention, a regulating end exhaust check valve 13 and an electric end exhaust check valve 10 are respectively provided at the steam outlet end of the regulating end cylinder 7 and the steam outlet end of the electric end cylinder 8, which are respectively used to discharge the steam in the regulating end cylinder 7 and the electric end cylinder 8 to the boiler cold section reheater.

[0037] Furthermore, in the present invention, the heaters through which steam is transmitted via the steam extraction pipeline are respectively heater No. 0, heater No. 1 and heater No. 2.

[0038] Furthermore, in the present invention, a high exhaust ventilation valve 12 is also provided at the steam outlet end of the regulating end cylinder 7 .

[0039] Specific implementation method 2: The control method of the steam turbine adapted to full load and high efficiency operation described in this implementation method is used to control the steam turbine adapted to full load and high efficiency operation, specifically comprising:

[0040] Obtain the total percentage of steam turbine load in real time, and when the total percentage of steam turbine load is lower than 50%, control the electric end regulating valve 2 to be fully opened;

[0041] When the total percentage of the steam turbine load is in the range of 50% to 100%, the electric end regulating valve 2 is controlled to be fully opened, and the regulating end regulating valve 4 is gradually opened to be fully opened as the percentage of the steam turbine load increases;

[0042] When the total percentage of the steam turbine load is higher than 100%, the electric end regulating valve 2, the regulating end regulating valve 4 and the supplementary steam valve 5 are all controlled to open.

[0043] Furthermore, in the present invention, a high-exhaust ventilation valve 12 is also provided at the steam outlet end of the regulating end cylinder 7. When the total load percentage of the turbine is lower than 50%, the high-exhaust ventilation valve 12 is also controlled to open to discharge the steam in the regulating end cylinder 7 to the condenser.

[0044] The electric end cylinder 8 and the regulating end cylinder 7 of the present invention are of combined cylinder type, the electric end flow and the regulating end flow are connected by a bridge steam seal 6, and the flow area of ​​the electric end flow and the regulating end flow is 50% of the rated design flow area.

[0045] When the unit is running at 100% load, the power-end regulating valve 2 and the regulating-end regulating valve 4 are fully opened, the main steam pressure, main steam temperature and feed water temperature are rated values, and the operation economy of the rated load of the steam turbine is guaranteed. When the unit is running at more than 100% load, the power-end regulating valve 2 and the regulating-end regulating valve 4 are fully opened, and the supplementary steam valve 5 is opened to maintain the main steam pressure at the rated value, and the unit load is increased to ensure the peak load capacity of the steam turbine.

[0046] When the unit is running at 50% to 100% load, the electric end regulating valve 2 is fully opened, the regulating end regulating valve 4 is gradually closed to closed, the regulating end flow steam passes through the regulating end exhaust check valve 13 to the boiler reheat cold section, and the electric end flow steam passes through the electric end exhaust check valve 10 to the boiler reheat cold section. The main steam pressure is always maintained at the rated parameters. The No. 1 heater is only arranged in the regulating end flow, and the pressure remains unchanged as the load decreases. Therefore, the cycle thermal efficiency of the turbine is maintained at a high level.

[0047] When the unit is running at a load lower than 50% to 100%, the regulating valve 2 at the power end is gradually closed, the regulating valve 4 at the regulating end is closed, the steam flowing through the regulating end is sent to the boiler reheating cold section through the regulating end exhaust check valve 13, and the steam flowing through the power end is sent to the condenser through the power end exhaust check valve 10. The power end flow is maintained at a zero-power operating state. The regulating end flow is responsible for the load control of the unit. The main steam pressure is slightly lower than the rated level. Therefore, the cycle thermal efficiency of the turbine is slightly reduced, but still remains at a relatively high level.

[0048] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A steam turbine adapted to full load and efficient operation, characterized in that: include: An electric end main steam valve (1), an electric end regulating valve (2), a regulating end main steam valve (3), a regulating end regulating valve (4), a supplementary steam valve (5), a regulating end cylinder (7), an electric end cylinder (8), a rotor (11) and a controller (9); The electric end main steam valve (1) and the electric end regulating valve (2) are connected in series; the steam inlet port of the electric end main steam valve (1) is connected to the main steam output pipeline of the boiler through a steam guide pipeline; The steam outlet of the electric end regulating valve (2) is connected to the steam inlet of the electric end cylinder (8), and the side wall of the electric end cylinder (8) is also provided with a second steam inlet, and the second steam inlet is connected to the main steam output pipeline of the boiler through the supplementary steam valve (5); The regulating end main steam valve (3) and the regulating end regulating valve (4) are connected in series; the steam inlet of the regulating end main steam valve (3) is connected to the main steam output pipeline of the boiler through another steam guide pipeline; The steam outlet of the regulating end regulating valve (4) is connected to the steam inlet port of the regulating end cylinder (7), the steam inlet end of the regulating end cylinder (7) is arranged opposite to the steam inlet end of the electric end cylinder (8), and a bridge steam seal (6) is arranged between the two to perform steam sealing on the steam inlet end of the regulating end cylinder (7) and the electric end cylinder (8); The rotor (11) penetrates the electric end cylinder (8) and the regulating end cylinder (7) and is coaxially arranged with the electric end cylinder (8) and the regulating end cylinder (7); The rotor (11) is provided with flow blades fixed on its body located in the power-end cylinder (8) and the regulating-end cylinder (7); and the flow blades are axially symmetrical about the axis of the rotor (11); The flow blades on the rotor (11) body of the electric end cylinder (8) are arranged in sections; a steam extraction pipeline is arranged between each section, and the steam is transmitted to the heater through the steam extraction pipeline; The main steam valve (1) at the power end and the main steam valve (3) at the regulating end are normally open valves; The controller (9) controls the switching of the electric end regulating valve (2), the regulating end regulating valve (4) and the supplementary steam valve (5) according to the total percentage of the steam turbine load.

2. The steam turbine adapted to full load and high efficiency operation according to claim 1, characterized in that: A regulating end exhaust check valve (13) and an electric end exhaust check valve (10) are respectively provided at the steam outlet end of the regulating end cylinder (7) and the steam outlet end of the electric end cylinder (8), and are respectively used to discharge the steam in the regulating end cylinder (7) and the electric end cylinder (8) to the boiler cold section reheater.

3. The steam turbine adapted to full load and high efficiency operation according to claim 1, characterized in that: The heaters through which steam is transmitted via the steam extraction pipeline are heater No. 0, heater No. 1 and heater No.

2.

4. The steam turbine adapted to full load and high efficiency operation according to claim 1, characterized in that: A high-discharge ventilation valve (12) is also provided at the steam outlet end of the regulating end cylinder (7).

5. A control method for a steam turbine adapted to full load and high efficiency operation, the method being used to control the above-mentioned steam turbine adapted to full load and high efficiency operation, characterized in that: Specifically include: Acquire the total percentage of steam turbine load in real time, and when the total percentage of steam turbine load is lower than 50%, control the electric end regulating valve (2) to be fully opened; When the total percentage of the steam turbine load is in the range of 50% to 100%, the electric end regulating valve (2) is controlled to be fully opened, and the regulating end regulating valve (4) is gradually opened to be fully opened as the percentage of the steam turbine load increases; When the total percentage of the steam turbine load is higher than 100%, the electric end regulating valve (2), the regulating end regulating valve (4) and the supplementary steam valve (5) are all controlled to open.

6. The control method of a steam turbine adapted to full-load high-efficiency operation according to claim 5, characterized in that: A high-discharge ventilation valve (12) is also provided at the steam outlet of the regulating end cylinder (7). When the total load percentage of the steam turbine is lower than 50%, the high-discharge ventilation valve (12) is controlled to open to discharge the steam in the regulating end cylinder (7) to the condenser.

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