Combined unit operation method and circulating power generation system

Abstract

The invention relates to the technical field of unit peak regulation, in particular to a combined unit operation method and a circulating power generation system.The combined unit operation method comprises the steps that the operation mode of a gas turbine and a steam turbine in a unit is converted into a control valve adjustment mode from a sliding pressure operation mode; receiving a peak regulation instruction from a power grid automatic power generation control system, and converting the peak regulation instruction into a control instruction; based on the converted control instruction, the opening degree of a unit rotating steam extraction partition plate is adjusted, when a load change instruction of a power grid automatic power generation control system is received, the load change instruction is distributed to a gas turbine and a steam turbine according to a preset proportion in a control valve adjusting mode, and the operation mode of the steam turbine is changed into control valve adjusting from sliding pressure operation; when a power grid AGC load change instruction is received, the load of the steam turbine can be quickly adjusted, so that the peak regulation speed of the whole combined cycle unit is increased by about 50%, and the response time is greatly shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of unit peak shaving, and particularly to a combined unit operation method and a circulating power generation system. Background Art

[0002] In existing gas turbine combined cycle power plants, peak shaving operations are usually completed by adjusting the load of the gas turbine through an automatic generation control (AGC) system. However, in this mode, the steam turbine usually operates in a sliding pressure mode, which means that the valve opening of the steam turbine remains 100% and does not participate in direct load control.

[0003] When the power of the gas turbine changes, the exhaust gas temperature changes accordingly, which in turn affects the heat entering the heat recovery steam generator and the main steam parameters, resulting in a slow change in the power of the steam turbine. Although this method reduces the throttling loss when the steam turbine valve admits steam, it also weakens the fast response ability of the steam turbine. In addition, the prior art does not fully utilize the peak shaving capacity of the distributed photovoltaic and wind power energy storage power station in the plant area, as well as the heat storage and energy storage potential of the heat supply pipeline network of the cogeneration unit. Summary of the Invention

[0004] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this part, the abstract, and the title. However, such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems of the steam turbine operating in a sliding pressure mode with poor regulation accuracy and long response time, the present invention is proposed.

[0006] Therefore, one of the purposes of the present invention is to provide a combined unit operation method.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: including converting the operating modes of the gas turbine and the steam turbine in the unit from the sliding pressure mode to the throttle valve regulation mode;

[0008] Receiving a peak shaving command from the grid automatic generation control system and converting it into a control command;

[0009] Based on the converted control command, adjusting the opening degree of the rotating extraction partition of the unit.

[0010] As a preferred solution of the combined unit operation method of the present invention, when receiving a load change command from the grid automatic generation control system, the load change command is distributed to the gas turbine and the steam turbine according to a preset ratio through the throttle valve regulation mode.

[0011] As a preferred embodiment of the operation method of the combined unit of the present invention, when distributing the load change command to the gas turbine and the steam turbine according to a preset ratio, the power ratio of the gas turbine to the steam turbine is set to 2:1.

[0012] As a preferred embodiment of the operation method of the combined unit of the present invention, the peak shaving command can be decomposed into multiple sub-commands.

[0013] The present invention also provides a combined cycle power generation system, including the above operation method of the combined unit, and further including a gas unit;

[0014] A steam unit;

[0015] A waste heat boiler module, which is connected to the gas unit and the steam unit;

[0016] A steam valve, which is connected to the steam unit, and the rate of the steam unit can be adjusted through the steam valve.

[0017] As a preferred embodiment of the combined cycle power generation system of the present invention, the gas unit includes,

[0018] A compressor;

[0019] A combustion chamber, which is connected to the compressor;

[0020] A gas turbine module, which is connected to the combustion chamber;

[0021] A gas generator, which is connected to the gas turbine module.

[0022] As a preferred embodiment of the combined cycle power generation system of the present invention, the steam unit includes,

[0023] An exciter, which is connected to the steam turbine through a generator.

[0024] As a preferred embodiment of the combined cycle power generation system of the present invention, the steam unit further includes,

[0025] A condenser;

[0026] A hot well module, which is connected to the condenser, and the water in the hot well module can be transported to the waste heat boiler module through a condensate pump;

[0027] As a preferred embodiment of the combined cycle power generation system of the present invention, the waste heat boiler module includes,

[0028] A high-pressure superheater, a high-pressure evaporator, a first high-pressure economizer;

[0029] A high-pressure steam drum, which is connected to the high-pressure superheater, the high-pressure evaporator, and the first high-pressure economizer.

[0030] As a preferred embodiment of the combined cycle power generation system of the present invention, wherein: the waste heat boiler module further includes

[0031] a second high-pressure economizer, a low-pressure evaporator, a low-pressure economizer, a deaerating evaporator, and a condensate heater;

[0032] a deaerator, which is connected to the second high-pressure economizer, the low-pressure evaporator, the low-pressure economizer, the deaerating evaporator, and the condensate heater.

[0033] Beneficial effects of the combined cycle power generation system of the present invention: By changing the steam turbine operation mode from sliding pressure operation to throttle governing, when receiving the AGC load change command from the power grid, the steam turbine load can be quickly adjusted, so that the peak shaving speed of the entire combined cycle unit is increased by about 50%, and the response time is greatly shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0035] Figure 1 It is a schematic diagram of the overall framework structure of a combined unit operation method and a cycle power generation system.

[0036] Figure 2 It is a system diagram of the steam turbine throttle governing to increase the AGC peak shaving capacity for a combined unit operation method and a cycle power generation system.

[0037] Figure 3 It is Figure 2 an enlarged view of the gas turbine unit in

[0038] Figure 4 It is Figure 2 an enlarged view of the steam valve in

[0039] Figure 5 It is Figure 2 an enlarged view of the waste heat boiler module in

[0040] Figure 6 It is Figure 2 an enlarged view of the steam turbine unit in

[0041] Figure 7 It is a schematic diagram of the principle of increasing the AGC peak shaving capacity by extracting steam for heat supply in a combined heat and power unit of a combined unit operation method and a cycle power generation system.

[0042] Figure 8 For Figure 7 the enlarged view of the steam turbine in

[0043] Figure 9 is a quick response AGC working flowchart of an energy storage power station for a combined unit operation method and a circulating power generation system. Specific embodiments

[0044] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the specification.

[0045] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0046] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0047] Thirdly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally out of the general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width and depth should be included.

[0048] Embodiment 1

[0049] Referring to Figure 1 and Figure 9 , this is the first embodiment of the present invention. This embodiment provides a combined unit operation method, including converting the operation modes of the gas turbine and the steam turbine in the unit from the sliding pressure operation mode to the throttle valve regulation mode;

[0050] Specifically, the gas turbine is used to convert the energy of fuel into electric energy, and the steam turbine is changed from the sliding pressure operation mode to the throttle valve regulation mode to improve the peak shaving speed and accuracy. When receiving the AGC load change command, the load is distributed according to the ratio of 2:1 (that is, the gas turbine undertakes 2 / 3 and the steam turbine undertakes 1 / 3). For the steam turbine part, according to the preset power change rate (for example, if the gas turbine is 10 MW / min, the steam turbine is set to 5 MW / min), the opening of the steam admission throttle valve is quickly adjusted to achieve rapid load increase and decrease. At the same time, the working state of the steam turbine is monitored in real time to ensure its operation within a safe range, and the control parameters are fine-tuned according to the actual situation.

[0051] Receive the peak shaving command from the automatic generation control system of the power grid and convert it into a control command;

[0052] Further, when the automatic generation control (AGC) of the gas-steam combined cycle unit issues a load change command, the load change command is distributed to the gas turbine and the steam turbine in a preset ratio, where the power ratio of the gas turbine to the steam turbine is 2:1, and the steam turbine responds quickly according to the preset power change rate and upper and lower limits.

[0053] Based on the converted control command, adjust the opening of the rotating extraction partition of the unit.

[0054] Further, when the power grid issues an AGC peak shaving command, according to the actual heat storage capacity of the heat supply network and the unit load condition, part of the AGC command is converted into an opening command of the rotating extraction partition of the unit.

[0055] Embodiment 2

[0056] Refer to Figures 1 - 9 , which is the second embodiment of the present invention. Different from the previous embodiment, when the load change command is distributed to the gas turbine and the steam turbine according to a preset ratio, the power ratio of the gas turbine to the steam turbine is set to 2:1.

[0057] Specifically, the peak shaving command can be decomposed into multiple sub-commands. By partially allocating the AGC command to the steam admission throttle valve of the steam turbine for adjustment according to the peak shaving capacity of the unit, the response speed of the initial AGC adjustment command is increased, and the overall adjustment speed can be increased by about 30%.

[0058] Confirm that the pressure of the heat supply pipeline of the cogeneration unit remains at about 1.5 MPa and the temperature is maintained at 320 °C to ensure good heat storage capacity. When the AGC command to increase power generation is issued by the power grid, reduce the opening of the industrial extraction steam electric control valve and open the extraction steam rotary baffle, so that more steam is used for power generation rather than heat supply. Through the above operations, the power generation can be quickly increased while reducing the external heat supply. On the contrary, when it is necessary to reduce the power generation, increase the opening of the industrial extraction steam electric control valve and close the extraction steam rotary baffle to increase the heat supply flow. With the support of the big data cloud computing center, dynamically adjust the working state of each steam separator in the heat supply pipeline to ensure the efficient operation of the entire system.

[0059] Embodiment 3

[0060] Refer to Figure 1 , which is the third embodiment of the present invention. Different from the above embodiments, this embodiment provides a combined cycle power generation system, including the above combined unit operation method. The operation modes of the gas turbine and the steam turbine are converted from the sliding pressure operation mode to the throttle valve 400 regulation mode. When operating under sliding pressure, it is fully open at 100%, while the throttle valve 400 regulation mode is adjusted according to the change rate.

[0061] Specifically, a gas unit 100; a steam unit 200; a waste heat boiler module 300, which is connected to the gas unit 100 and the steam unit 200; a throttle valve 400, which is connected to the steam unit 200, and the rate of the steam unit 200 can be adjusted through the throttle valve 400.

[0062] Embodiment 4

[0063] Refer to Figures 1 - 3 , which is the fourth embodiment of the present invention. Different from the previous embodiment: a compressor 101; a combustion chamber 102, which is connected to the compressor 101; a gas turbine module 103, which is connected to the combustion chamber 102; a gas generator 104, which is connected to the gas turbine module 103.

[0064] Specifically, the compressor 101 is used to compress air for use in the combustion process of the combustion chamber 102. The combustion chamber 102 is connected to the compressor 101. By adding fuel and burning, the chemical energy is converted into heat energy to generate high-temperature and high-pressure gas. The gas turbine module 103 receives the high-temperature and high-pressure gas from the combustion chamber 102, drives the turbine to rotate, and converts the heat energy into mechanical energy. And the gas generator 104 is connected to the gas turbine module 103 to convert the mechanical energy into electrical energy and supply it to the power grid or energy storage device.

[0065] First, start the compressor 101 to begin pressurizing the air and send it into the combustion chamber 102. During this process, adjust the operating state of the compressor 101 to ensure that the quality of the air entering the combustion chamber 102 meets the requirements of combustion efficiency. Inside the combustion chamber 102, the pre-mixed fuel is mixed with the high-pressure air and then ignited. The resulting high-temperature and high-pressure gas then enters the gas turbine module 103. This step requires precise control of the fuel supply to optimize combustion efficiency and reduce emissions.

[0066] Among them, when the power grid issues an AGC (Automatic Generation Control) command, the entire system needs to respond quickly. At this time, the gas turbine module 103 quickly adjusts its operating state and adjusts the output power according to the command changes. To further improve the peak shaving speed and accuracy, this embodiment introduces the support of a distributed wind and solar power station and an energy storage system. When the power grid load demand suddenly increases, the energy storage power station can release the stored energy in milliseconds to assist the gas power generation system to quickly reach the target output.

[0067] In addition, combined with the heat storage capacity of the heat supply pipeline network, when the unit is operating at low load and there is a large demand for heat supply, the proportion of power supply or heat supply to the outside can be adjusted by adjusting the opening of the extraction steam baffle, so as to achieve more flexible peak shaving operation.

[0068] Embodiment 5

[0069] Refer to Figure 2 and Figures 4 - 8 This is the fifth embodiment of the present invention. Different from the previous embodiment, the steam turbine unit 200 includes an exciter 201, which is connected to a steam turbine 203 through a generator 202.

[0070] The steam turbine unit 200 further includes a condenser 204; a hot well module 205, which is connected to the condenser 204, and through a condensate pump 206, the water in the hot well module 205 can be transported to the waste heat boiler module 300.

[0071] Specifically, by controlling the magnetic field intensity of the generator 202, the stability of the output voltage and current of the generator 202 is adjusted. The generator 202 is connected to the exciter 201 and is driven by the steam turbine 203 to convert mechanical energy into electrical energy. The steam turbine 203 uses the steam generated from the waste heat boiler module 300 to operate and drives the generator 202 to generate electricity. The condenser 204 is used to cool the steam discharged from the steam turbine 203 and condense it into water. The hot well module 205 is directly connected to the condenser 204 to receive and store the condensed water. The condensate pump 206 is responsible for transporting the condensed water in the hot well module 205 back to the waste heat boiler module 300 to complete the cycle.

[0072] Moreover, when the power grid load demand changes, especially in cases where rapid response is required, the power generation power can be quickly adjusted by regulating the intake steam volume of the steam turbine 203. With the assistance of the energy storage system and distributed wind and solar power plants, the peak shaving capacity and accuracy of the entire system can be further enhanced. For example, during low load periods, if there is still a large heating demand, the extraction steam baffle opening can be adjusted to flexibly switch between power supply and heating to meet different energy demands.

[0073] Embodiment 6

[0074] Referring to Figure 2 and Figure 5 , this is the sixth embodiment of the present invention. Different from the previous embodiment, the waste heat boiler module 300 includes a high-pressure superheater 301, a high-pressure evaporator 302, and a first high-pressure economizer 303; a high-pressure steam drum 304, which is connected to the high-pressure superheater 301, the high-pressure evaporator 302, and the first high-pressure economizer 303.

[0075] The waste heat boiler module 300 further includes a second high-pressure economizer 305, a low-pressure evaporator 306, a low-pressure economizer 307, a deaerating evaporator 308, and a condensate heater 309; a deaerator 310, which is connected to the second high-pressure economizer 305, the low-pressure evaporator 306, the low-pressure economizer 307, the deaerating evaporator 308, and the condensate heater 309.

[0076] Specifically, the high-pressure superheater 301 is used to further heat the high-pressure steam to make it reach a higher temperature and pressure. The high-pressure evaporator 302 converts water into high-pressure steam to provide power for the steam turbine. The first high-pressure economizer 303 preheats the feed water entering the high-pressure evaporator to improve the system efficiency. The high-pressure steam drum 304 connects and coordinates the operation of the high-pressure superheater 301, the high-pressure evaporator 302, and the first high-pressure economizer 303 to ensure smooth water flow and steam flow between the components.

[0077] The low-pressure evaporator 306 is used to generate low-pressure steam, which is suitable for low load demands or specific process flows. The low-pressure economizer 307 preheats the feed water entering the low-pressure evaporator to improve the overall system efficiency. The deaerating evaporator 308 removes the dissolved oxygen in the water to prevent corrosion and uses waste heat for preliminary heating. The condensate heater 309 is used to heat the condensate returned from the condenser to reduce energy loss. The deaerator 310 is connected to the second high-pressure economizer 305, the low-pressure evaporator 306, the low-pressure economizer 307, the deaerating evaporator 308, and the condensate heater 309, and is responsible for removing the oxygen in the water to ensure pure water quality and regulating the water level and temperature in the system.

[0078] Among them, the high-temperature flue gas passes through the high-pressure superheater 301, the high-pressure evaporator 302 and the first high-pressure economizer 303, gradually heating the feed water and generating high-pressure steam. The high-pressure steam drum 304 maintains the stable operation of the system and ensures the coordinated operation among various heat exchangers. In the low-pressure part, the low-pressure evaporator 306 generates low-pressure steam to meet different process requirements. The low-pressure economizer 307 preheats the feed water entering the low-pressure evaporator to improve the overall efficiency. After being heated by the condensate heater 309, the condensate enters the deaerator 310 to remove the dissolved oxygen, and is further preheated by the second high-pressure economizer 305, and finally returns to the high-pressure evaporator 302 to form a cycle.

[0079] Moreover, when the grid load changes, the water inflow and steam output of the high-pressure evaporator 302 and the low-pressure evaporator 306 can be adjusted to quickly respond to the grid demand. Combining the millisecond-level response ability of the energy storage power station and the heat storage capacity of the heat supply pipeline network, the power generation power can be greatly adjusted within a short time, improving the peak shaving accuracy and speed. The deaeration evaporator 308 and the deaerator 310 are used to ensure pure water quality and extend the service life of the equipment. At the same time, by optimizing the working parameters of each component, efficient energy recovery and utilization are achieved.

[0080] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A combined unit operation method, characterized in that: include, Convert the gas turbine and steam turbine operation mode in the unit from sliding pressure operation to valve regulation mode; Receive peak load regulation instructions from the automatic power generation control system of the power grid and convert them into control instructions; Based on the converted control instructions, the opening of the unit's rotary steam extraction partition is adjusted.

2. A combined unit operation method according to claim 1, characterized in that: When receiving a load change instruction from the automatic power generation control system of the power grid, the load change instruction is distributed to the gas turbine and the steam turbine according to a preset ratio through the throttle adjustment method.

3. A combined unit operation method as claimed in claim 2, characterized in that: When the load change command is distributed to the gas turbine and the steam turbine according to a preset ratio, the power ratio of the gas turbine to the steam turbine is set to 2:

1.

4. A combined unit operation method as claimed in claim 3, characterized in that: The peak shaving instruction can be decomposed into a plurality of sub-instructions.

5. A combined cycle power generation system, characterized in that: A combined unit operation method according to any one of claims 1 to 4 is adopted, comprising: Gas unit (100); Steam unit (200); A waste heat boiler module (300) connected to the gas unit (100) and the steam unit (200); A steam valve (400) is connected to the steam unit (200), and the speed of the steam unit (200) can be adjusted through the steam valve (400).

6. A combined cycle power generation system according to claim 5, characterized in that: The gas unit (100) comprises: Compressor (101); A combustion chamber (102) connected to the compressor (101); A gas turbine module (103) connected to the combustion chamber (102); A gas generator (104) is connected to the gas turbine module (103).

7. A combined cycle power generation system according to claim 6, characterized in that: The steam unit (200) comprises: An exciter (201) is connected to a steam turbine (203) via a generator (202).

8. A combined cycle power generation system according to claim 7, characterized in that: The steam unit (200) further comprises: Condenser (204); The hot well module (205) is connected to the condenser (204), and the water in the hot well module (205) can be transported to the waste heat boiler module (300) through the condensate pump (206).

9. A combined cycle power generation system according to claim 8, characterized in that: The waste heat boiler module (300) comprises: A high-pressure superheater (301), a high-pressure evaporator (302), and a first high-pressure economizer (303); The high-pressure steam drum (304) is connected to the high-pressure superheater (301), the high-pressure evaporator (302), and the first high-pressure economizer (303).

10. A combined cycle power generation system according to claim 9, characterized in that: The waste heat boiler module (300) further comprises: A second high-pressure economizer (305), a low-pressure evaporator (306), a low-pressure economizer (307), a deaerator evaporator (308), and a condensate heater (309); The deaerator (310) is connected to the second high-pressure economizer (305), the low-pressure evaporator (306), the low-pressure economizer (307), the deaerator evaporator (308), and the condensate heater (309).

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