A feedwater pump turbine combined system and control method

Abstract

This invention discloses a feedwater pump turbine combined system and control method. The feedwater pump turbine combined system includes: an intermediate-pressure cylinder, N back-pressure turbines, M condensing turbines, and Z valves. The N back-pressure turbines can be N feedwater pump turbines, and the M condensing turbines can be M feedwater pump turbines. The Z valves are located between the intermediate-pressure cylinder and the N back-pressure turbines, between the intermediate-pressure cylinder and the M condensing turbines, and between the N back-pressure turbines and the M condensing turbines, respectively. The control method includes an automatic adjustment step, which includes: collecting steam source pressure values, state switching, and driving the feedwater pump turbines. The automatic adjustment module includes: a steam source pressure P collection module, a valve control module, a turbine drive module, and a cloud data feedback module. Using this invention can improve the operational economy of the feedwater pump turbine system and ensure the safe operation of the turbine unit.

Description

Technical Field

[0001] This invention belongs to the field of feedwater pump turbine technology, and relates to a feedwater pump turbine combined system and control method. Using this invention can improve the operating economy of the feedwater pump turbine system and ensure the safe operation of the turbine unit. Background Technology

[0002] Currently, thermal power units generally require deep peak shaving. In existing technologies, when the unit is operating under peak shaving conditions, the feedwater pump turbine usually needs to be switched to a high-parameter steam source. However, when the high-parameter steam source enters the feedwater pump turbine, throttling is required, which will cause economic losses. On the other hand, the steam source switching operation requires very careful attention when switching to a high-parameter steam source. If the operation is not done properly, the feedwater pump turbine will trip, which will not only affect the normal operation of the unit, but may even lead to a major safety accident. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings in safety and economy of feedwater pump turbines when switching to high-parameter steam sources in the prior art, and to provide a feedwater pump turbine combined system and control method, thereby solving the technical problems of safety and economy of feedwater pump turbines when switching to high-parameter steam sources.

[0004] The present invention relates to a feedwater pump turbine combined system, which may include one intermediate-pressure cylinder, characterized in that the system comprises:

[0005] The system consists of N back-pressure steam turbines, M condensing steam turbines, and Z valves. Specifically, the N back-pressure steam turbines can be used as N feedwater pump turbines, and the M condensing steam turbines can be used as M feedwater pump turbines. The Z valves are located between the intermediate-pressure cylinder and the N back-pressure steam turbines, the intermediate-pressure cylinder and the M condensing steam turbines, and the N back-pressure steam turbines and the M condensing steam turbines, respectively, and serve to switch on and off the flow of steam.

[0006] Where N, M, and Z are natural numbers greater than or equal to 1. The intermediate-pressure cylinder can be omitted, or replaced by a steam turbine.

[0007] Furthermore, when deep peak shaving occurs, M condensing steam turbines operate normally, N back-pressure steam turbines are shut down, and the valves between the N steam turbines and the intermediate pressure cylinder are closed.

[0008] The feed water pump steam turbine combined system described in the content of the present invention is characterized in that the system includes: 1 back-pressure steam turbine, 1 condensing steam turbine and 3 valves. Among them: 1 back-pressure steam turbine can be 1 feed water pump steam turbine, 1 condensing steam turbine can be 1 feed water pump steam turbine, and the 3 valves are Valve 1, Valve 2 and Valve 3. And Valve 1 is between the intermediate pressure cylinder and 1 back-pressure steam turbine, Valve 2 is between the intermediate pressure cylinder and 1 condensing steam turbine, and Valve 3 is between 1 back-pressure steam turbine and 1 condensing steam turbine.

[0009] Further, when deep peak shaving occurs, 1 condensing steam turbine operates normally, 1 back-pressure steam turbine stops, and the valve between 1 steam turbine and the intermediate pressure cylinder is closed.

[0010] Further, Valve 1 between the intermediate pressure cylinder and 1 back-pressure steam turbine has a certain pressure starting ability. When the steam source pressure is less than a certain threshold value P1, Valve 1 automatically closes.

[0011] Further, Valve 1, Valve 2 and Valve 3 also have a certain pressure starting ability. When the steam source pressure is less than certain threshold values P2 and P3, Valve 2 and Valve 3 automatically close and P2 is greater than or equal to P3.

[0012] Further, when the steam source pressure is a certain threshold value P4 (0.3 MPa), M condensing steam turbines operate normally and N back-pressure steam turbines stop. At this time, P2 < P4 < P3, the value of P4 is (0.2 MPa), and P3 is (0.4 MPa).

[0013] Further, among them, Feed Water Pump Steam Turbine A is a back-pressure feed water pump steam turbine, and Feed Water Pump Steam Turbine B is a condensing feed water pump steam turbine. When the unit operates normally, Valve 1 and Valve 3 are opened and Valve 2 is closed. At this time, assuming that the intermediate extraction pressure of the large steam turbine is 0.8 MPa, after doing work in Feed Water Pump Steam Turbine A, assuming that the exhaust pressure of Feed Water Pump Steam Turbine A is 0.4 MPa, it then enters Feed Water Pump Steam Turbine B to do work. When the unit performs deep peak shaving, assuming that the intermediate extraction pressure of the large steam turbine drops to 0.4 MPa, then Valve 1 and Valve 3 are closed and Valve 2 is opened, and the steam source of the large steam turbine directly enters Feed Water Pump Steam Turbine B to do work.

[0014] The feed water pump steam turbine combined system described in the content of the present invention is characterized in that the system includes: an automatic adjustment module, and the automatic adjustment module includes: a steam source pressure P collection module, a valve control module, a steam turbine drive module, and a cloud data feedback module. The modules are electrically connected by wireless or wired means.

[0015] The feed water pump steam turbine combined system described in the content of the present invention is characterized in that the system includes: an automatic adjustment module, and the automatic adjustment module includes:

[0016] Steam source pressure collection module: collects the pressure value output by the steam source, which can output to the feed water pump to perform work. The steam source pressure value is related to the required load value PW under certain conditions, and serves as the basis for valve state switching.

[0017] Valve control module: It compares the collected steam source pressure value P with a certain pressure threshold (Py), and adjusts the opening or closing of the valve by adjusting the control module according to the comparison result;

[0018] Steam turbine drive module: Receives control commands from the automatic regulation module and outputs the control commands to the steam turbine and valves of the feedwater pump-steam turbine combination system to control the start-up and shutdown of the steam turbine and the opening and closing of the valves;

[0019] Cloud-based data feedback module: Saves the pressure value P collected in the automatic operation mode of the feedwater pump turbine combined system, and uses the difference between the P value and Py to optimize the turbine drive module.

[0020] The present invention also includes: a control method for a feedwater pump turbine combined system, characterized in that: it includes an automatic adjustment step, the automatic adjustment step including:

[0021] Step A is the step of collecting the steam source pressure P value, which is the required steam source pressure under certain conditions and is related to the load PW value.

[0022] Step B is a state switching step, in which the state switching step can output a certain driving step command, which drives step C to run normally.

[0023] Step C, the step of driving the feedwater pump turbine, wherein when the unit is under load for a certain period of time, feedwater pump turbine A starts running and feedwater pump turbine B runs; when the unit is under low load or partial load, feedwater pump turbine A stops running and feedwater pump turbine B runs.

[0024] The control method for the feedwater pump turbine combined system is characterized by including two operating modes. Mode 1: Feedwater pump turbine A is a back-pressure feedwater pump turbine, and feedwater pump turbine B is a condensing feedwater pump turbine. During normal operation, valves 1 and 3 are open, valve 2 is closed, and the discharge pressure of the main turbine is 0.8 MPa. After the main turbine enters feedwater pump turbine A to perform work, the discharge pressure of feedwater pump turbine A is 0.4 MPa, and then the main turbine enters feedwater pump turbine B to perform work. Mode 2: When the unit is in deep peak shaving, assuming the discharge pressure of the main turbine drops to 0.4 MPa, valves 1 and 3 are closed, valve 2 is opened, and the main turbine steam source directly enters feedwater pump turbine B to perform work.

[0025] The control method of the feed water pump steam turbine combined system is characterized in that it further includes a pressure comparison step, and this pressure comparison step includes:

[0026] When the steam source pressure is a certain threshold value P4 (0.3 MPa), M condensing steam turbines are operating normally, and N back-pressure steam turbines are shut down. At this time, P2 < P4 < P3, the P4 value is (0.2 MPa), and P3 is (0.4 MPa).

[0027] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0028] (1) The present invention adopts the combination of a back-pressure steam turbine and a condensing steam turbine. When the unit is operating normally, the back-pressure feed water pump steam turbine and the condensing feed water pump steam turbine operate simultaneously. When the unit performs deep peak shaving, the back-pressure feed water pump steam turbine is shut down, and the condensing feed water pump steam turbine operates, so as to achieve flexible adjustment;

[0029] (2) By adopting the feed water pump steam turbine combined system and control method of the present invention, the technical problems of the safety and economy of the feed water pump steam turbine in the prior art when switching to a high-parameter steam source are solved. By adopting the present invention, the operating economy of the feed water pump steam turbine system can be improved, the safe operation of the steam turbine unit can be ensured, it has a good application prospect, has good social and economic benefits, and can meet the needs of the dual-carbon development goal. Brief Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the prior art principle;

[0031] Figure 2 It is a schematic diagram of the principle of a feed water pump steam turbine combined system of the present invention;

[0032] Figure 3 It is a schematic diagram of another feed water pump steam turbine combined system of the present invention. Detailed Embodiments

[0033] The embodiments given below are intended to further illustrate the present invention, but should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the above content of the present invention still fall within the protection scope of the present invention.

[0034] Embodiment: Refer to the attached Figure 2 .

[0035] A feedwater pump turbine combined system is provided, which includes one intermediate-pressure cylinder. The system comprises one back-pressure turbine, one condensing turbine, and three valves. The back-pressure turbine is a feedwater pump turbine, the condensing turbine is a feedwater pump turbine, and the three valves are valve 1, valve 2, and valve 3. Valve 1 is located between the intermediate-pressure cylinder and the back-pressure turbine, valve 2 is located between the intermediate-pressure cylinder and the condensing turbine, and valve 3 is located between the back-pressure turbine and the condensing turbine.

[0036] When deep peak shaving occurs, one condensing steam turbine operates normally, one back-pressure steam turbine is shut down, and the valve between one steam turbine and the intermediate pressure cylinder is closed.

[0037] Valve 1, located between the intermediate pressure cylinder and a back-pressure steam turbine, has a certain pressure start-up capability. When the steam source pressure is less than a certain threshold value P1, valve 1 automatically closes.

[0038] Valves 2 and 3 also have a certain pressure start-up capability. When the steam source pressure is less than a certain threshold value P2 and P3, valves 2 and 3 will automatically close and P2 will be greater than or equal to P3.

[0039] In order to adapt to the development of current intelligent technology and utilize big data technology, the feedwater pump turbine combined system described in this embodiment of the invention further includes: an automatic adjustment module, which includes: a steam source pressure P collection module, a valve control module, a turbine drive module, and a cloud data feedback module. The modules are electrically connected to each other through wireless or wired means.

[0040] The automatic adjustment module specifically includes:

[0041] Steam source pressure collection module: collects the pressure value output by the steam source, which can output to the feed water pump to perform work. The steam source pressure value is related to the required load value PW under certain conditions, and serves as the basis for valve state switching.

[0042] Valve control module: It compares the collected steam source pressure value P with a certain pressure threshold (Py), and adjusts the opening or closing of the valve by adjusting the control module according to the comparison result;

[0043] Steam turbine drive module: Receives control commands from the automatic regulation module and outputs the control commands to the steam turbine and valves of the feedwater pump-steam turbine combination system to control the start-up and shutdown of the steam turbine and the opening and closing of the valves;

[0044] Cloud-based data feedback module: Saves the pressure value P collected in the automatic operation mode of the feedwater pump turbine combined system, and uses the difference between the P value and Py to optimize the turbine drive module.

[0045] In addition, the embodiments of the present invention further include: a control method for a feed water pump steam turbine combined system, including an automatic adjustment step, and the automatic adjustment step includes:

[0046] Step A, a step of collecting the value of the steam source pressure P, where the P value is the required steam source pressure under certain conditions and is related to the load PW value;

[0047] Step B, a state switching step, where the state switching step can output a certain driving step command, and this driving step command drives Step C to operate normally;

[0048] Step C, a step of driving the feed water pump steam turbine to operate. Among them, when the unit is operating at a load within a certain period of time, Feed Water Pump Steam Turbine A starts to operate, and Feed Water Pump Steam Turbine B operates; when the unit is operating at a low load or partial load, Feed Water Pump Steam Turbine A stops operating, and Feed Water Pump Steam Turbine B operates.

[0049] The control method for the feed water pump steam turbine combined system described above includes two operating modes. Mode 1 is: Feed Water Pump Steam Turbine A is a back-pressure type feed water pump steam turbine, and Feed Water Pump Steam Turbine B is a condensing type feed water pump steam turbine. When the unit is operating normally, Valve 1 and Valve 3 are opened, Valve 2 is closed, the extraction pressure of the main turbine is 0.8 MPa. After entering Feed Water Pump Steam Turbine A to do work, the exhaust pressure of Feed Water Pump Steam Turbine A is 0.4 MPa, and then it enters Feed Water Pump Steam Turbine B to do work; Mode 2, when the unit is in deep peak shaving, assuming that the extraction pressure of the main turbine drops to 0.4 MPa, then Valve 1 and Valve 3 are closed, Valve 2 is opened, and the steam source of the main turbine directly enters Feed Water Pump Steam Turbine B to do work.

[0050] The control method for the feed water pump steam turbine combined system also includes a pressure comparison step, and this pressure comparison step includes:

[0051] When the steam source pressure is a certain threshold value P4 (0.3 MPa), M condensing steam turbines operate normally, and N back-pressure steam turbines stop operating. At this time, P2 < P4 < P3, the P4 value is (0.2 MPa), and P3 is (0.4 MPa).

[0052] The above specific technical solutions are only used to illustrate the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above specific technical solutions, those of ordinary skill in the art should understand that: they can still modify the above specific technical solutions, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the present invention.

[0053] The technical content not specifically described in the present invention and the above embodiments is the same as the prior art.

[0054] The present invention is not limited to the above embodiments; all embodiments described herein can be implemented and have the aforementioned good effects.

Claims

1. A feedwater pump turbine combined system, the system comprising one intermediate-pressure cylinder, characterized in that, The system includes: The system consists of N back-pressure steam turbines, M condensing steam turbines, and Z valves. Specifically, the N back-pressure steam turbines are the same as the N feedwater pump turbines, the M condensing steam turbines are the same as the M feedwater pump turbines, and the Z valves are located between the intermediate-pressure cylinder and the N back-pressure steam turbines, the intermediate-pressure cylinder and the M condensing steam turbines, and the N back-pressure steam turbines and the M condensing steam turbines, respectively. During deep peak shaving, the condensing steam turbines operate normally, the back-pressure steam turbines are shut down, and the valves between the back-pressure steam turbines and the intermediate-pressure cylinder are closed. The system also includes: an automatic adjustment module, which comprises: a steam source pressure collection module, a valve control module, a steam turbine drive module, and a cloud data feedback module, wherein the modules are electrically connected wirelessly or via wired means; wherein: Steam source pressure collection module: collects the steam source pressure value output by the steam source, which can output to the feed water pump to complete the work. The steam source pressure value is related to the required load value PW under certain conditions, and serves as the basis for valve state switching. Valve control module: It compares the collected steam source pressure value P with a certain pressure threshold Py, and adjusts the opening or closing of the control valve according to the comparison result; Steam turbine drive module: Receives control commands from the automatic regulation module and outputs the control commands to the steam turbine and valves of the feedwater pump-steam turbine combination system to control the start-up and shutdown of the steam turbine and the opening and closing of the valves; Cloud-based data feedback module: Saves the pressure value P collected in the automatic operation mode of the feedwater pump turbine combined system, and compares the P value with Py to optimize the turbine drive module in reverse.

2. The feedwater pump turbine combined system according to claim 1, characterized in that, The system includes: one back-pressure steam turbine and one condensing steam turbine, and three valves. The back-pressure steam turbine is a feedwater pump turbine, and the condensing steam turbine is a feedwater pump turbine. The three valves are valve 1, valve 2, and valve 3. Valve 1 is located between the intermediate pressure cylinder and the back-pressure steam turbine, valve 2 is located between the intermediate pressure cylinder and the condensing steam turbine, and valve 3 is located between the back-pressure steam turbine and the condensing steam turbine.

3. A control method for a feedwater pump turbine combined system, used for controlling the feedwater pump turbine combined system as described in claim 2; Its features are: This includes an automatic adjustment step, which includes: Step A is the step of collecting the steam source pressure value P, which is the required steam source pressure under certain conditions and is related to the load value PW. Step B is a state switching step, in which the state switching step can output a certain driving step command, which drives step C to run normally. Step C, the step of driving the feedwater pump turbine, wherein feedwater pump turbine A is a back-pressure feedwater pump turbine, and feedwater pump turbine B is a condensing feedwater pump turbine. When the unit is running at high load for a certain period of time, feedwater pump turbine A starts running and feedwater pump turbine B runs; when the unit is running at low load or partial load, feedwater pump turbine A stops running and feedwater pump turbine B runs.

4. The control method for the feedwater pump turbine combined system according to claim 3, characterized in that: There are two operating modes. Mode 1: Feedwater pump turbine A is a back-pressure feedwater pump turbine, and feedwater pump turbine B is a condensing feedwater pump turbine. During normal operation, valves 1 and 3 are open, valve 2 is closed, and the main turbine's discharge pressure is 0.8 MPa. After entering feedwater pump turbine A to perform work, the discharge pressure of feedwater pump turbine A is 0.4 MPa, and then it enters feedwater pump turbine B to perform work. Mode 2: When the unit is in deep peak shaving, assuming the main turbine's discharge pressure drops to 0.4 MPa, valves 1 and 3 are closed, valve 2 is open, and the main turbine's steam source directly enters feedwater pump turbine B to perform work.

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