A steam pressure matching system for a thermal power plant

Abstract

The utility model provides a kind of steam pressure matching system for thermal power plant, the system includes steam desuperheater, pressure matcher, sensor unit, actuator unit and control unit, by pressure matcher injection mixing high, low pressure steam, promotion is usable medium pressure steam;Through steam desuperheater water spray cooling;Control unit according to the pressure transmitter and temperature sensor signal on medium pressure steam supply pipe, after PID operation, drive actuator, adjust desuperheating water valve and steam valve opening, realize closed-loop control.The utility model recycles and utilizes surplus low pressure steam, avoids energy waste and noise pollution of empty discharge, guarantees the safe operation of unit, improves economic benefit and energy efficiency.

Description

Technical Field

[0001] This utility model relates to the field of steam power generation technology, specifically to a steam pressure matching system for thermal power plants. Background Technology

[0002] In combined heat and power (CHP) systems of thermal power plants, the low-pressure exhaust steam from the turbine units is typically supplied as industrial steam. However, downstream users' steam demand fluctuates significantly, especially during the non-heating season or at night, when steam consumption drops sharply. When user steam consumption is far below the turbine's designed minimum exhaust capacity, it causes a sudden increase in pressure in the low-pressure exhaust pipeline. To ensure the safety of the unit and prevent overpressure operation, the traditional practice is to manually or automatically open the "air vent valve" to directly release excess low-pressure steam into the atmosphere. While this method solves the safety problem simply and directly, it results in the waste of high-quality thermal energy, accompanied by significant noise and working fluid loss, leading to poor operational economy.

[0003] This energy waste not only increases production costs and reduces overall energy efficiency for enterprises, but also runs counter to the national "dual-carbon" strategy and energy conservation policies. Therefore, thermal power plants have a strong intrinsic motivation to find a technological solution that can both ensure safe operation and recover and utilize this surplus steam. Through technological improvements, the previously wasted energy can be converted into usable medium-pressure steam, creating direct economic benefits for enterprises and contributing to the nation's energy conservation and emission reduction goals, achieving a win-win situation for both enterprises and society. Summary of the Invention

[0004] The purpose of this invention is to provide a steam pressure matching system for thermal power plants, which can intelligently adjust steam parameters to achieve safe, efficient and automated steam recovery and utilization.

[0005] To achieve the above objectives, the present invention proposes the following technical solution:

[0006] A steam pressure matching system for a thermal power plant, comprising:

[0007] Pressure matching device, steam desuperheater, sensor unit, actuator unit, and control unit;

[0008] The steam desuperheater includes a desuperheater body and a water supply mechanism. The front end and rear end of the desuperheater body are respectively provided with a primary steam inlet and a secondary steam outlet. The water supply mechanism is connected to the desuperheater body and is provided with at least one desuperheating water inlet.

[0009] The pressure matching device includes an inlet chamber, a mixing chamber, and a diffuser chamber connected in sequence. The inlet chamber is provided with a high-pressure steam inlet, which is connected to the secondary steam outlet or a high-pressure steam supply pipe. The mixing chamber is provided with at least one low-pressure steam inlet. The diffuser chamber is provided with a medium-pressure steam outlet at its rear end, which is connected to a medium-pressure steam supply pipe or the primary steam inlet.

[0010] The sensor unit is installed on the medium-pressure steam supply pipe and is used to monitor the medium-pressure steam state parameters in the medium-pressure steam supply pipe in real time.

[0011] The actuator unit is located on the pressure matching device and / or the water supply mechanism, and is used to drive and control the steam pressure of the pressure matching device or the steam temperature of the steam desuperheater;

[0012] The control unit is electrically connected to the sensor unit and the actuator unit.

[0013] As a preferred technical solution of this utility model, the desuperheater body is provided with a tapering tube, a mixing tube and a diffusion tube connected in sequence, the front end of the tapering tube is the primary steam inlet and the rear end of the diffusion tube is the secondary steam outlet.

[0014] The water supply mechanism includes a water supply regulating valve and a connecting pipe. One end of the connecting pipe is connected to the water supply regulating valve, and the other end is provided with at least one desuperheating water nozzle. One of the desuperheating water nozzles extends into the converging pipe, and the other desuperheating water nozzle is either connected to the diffuser chamber or closed.

[0015] As a preferred embodiment of this utility model, the actuator unit includes a temperature actuator disposed at the top of the water supply regulating valve, and the temperature actuator is electrically connected to the water supply regulating valve and the control unit respectively;

[0016] The sensor unit includes a temperature sensor, which is electrically connected to the control unit and is used to monitor the temperature of the medium-pressure steam in real time.

[0017] As a preferred embodiment of this utility model, a steam regulating valve is provided between the air inlet chamber and the mixing chamber;

[0018] The actuator unit includes a pressure actuator, which is electrically connected to the steam regulating valve and the control unit;

[0019] The sensor unit includes a pressure transmitter, which is electrically connected to the control unit and is used to monitor the pressure of the medium-pressure steam in real time.

[0020] As a preferred technical solution of this utility model, the steam desuperheater is arranged in front of the pressure matching device, the primary steam inlet is connected to the high-pressure steam supply pipe, and the secondary steam outlet is connected to the high-pressure steam inlet, while the medium-pressure steam outlet is connected to the medium-pressure steam supply pipe.

[0021] The connecting pipe has only one desuperheating water nozzle that extends into the tapered pipe.

[0022] As a preferred embodiment of this utility model, the steam desuperheater is located at the rear of the pressure matching device, the primary steam inlet is connected to the medium-pressure steam outlet, and the secondary steam outlet is connected to the medium-pressure steam supply pipe. At the same time, the high-pressure steam inlet is connected to the high-pressure steam supply pipe.

[0023] The connecting pipe has only one desuperheating water nozzle that extends into the tapered pipe.

[0024] As a preferred technical solution of this utility model, the steam desuperheater is arranged in front of the pressure matching device, the primary steam inlet is connected to the high-pressure steam supply pipe, and the secondary steam outlet is connected to the high-pressure steam inlet. At the same time, the medium-pressure steam outlet is connected to the medium-pressure steam supply pipe.

[0025] The connecting pipe is equipped with two desuperheating water nozzles, one of which extends into the converging pipe, and the other desuperheating water nozzle is connected to the diffuser chamber.

[0026] As a preferred embodiment of this utility model, the control unit is a distributed control system, comprising:

[0027] A signal input module is used to receive signals from the pressure transmitter and the temperature sensor;

[0028] The control processing unit is used to run the PID control algorithm and generate control commands.

[0029] The signal output module is used to send the control commands to the temperature actuator and the pressure actuator.

[0030] As a preferred embodiment of this utility model, the medium-pressure steam supply pipe is also connected to a steam exhaust pipe.

[0031] As can be seen from the above technical solutions, this utility model provides a steam pressure matching system for thermal power plants, which has the following significant advantages compared with the prior art.

[0032] 1. By using a pressure matching device to mix surplus low-pressure steam and some high-pressure steam to raise it into usable medium-pressure steam, the loss of heat, working fluid and energy caused by the emission of low-pressure steam into the air is completely avoided, and the overall energy utilization efficiency is significantly improved, which is in line with the national energy conservation and emission reduction policy.

[0033] 2. By introducing a DCS-based intelligent control system and combining it with PID algorithms, precise closed-loop regulation of steam pressure and temperature is achieved, which significantly improves the system's automation level and energy utilization efficiency, avoids untimely and inaccurate manual intervention, adapts to operating conditions with strong load fluctuations, and effectively prevents the turbine unit from tripping or being damaged due to excessive pressure, thus ensuring the safety and economy of system operation.

[0034] 3. The desuperheater body adopts a special structure of tapering tube, mixing tube and diffuser tube to ensure that the steam flow rate and desuperheating water atomization effect are still good under low flow conditions, thus broadening the operating range of the system.

[0035] 4. The system supports three connection methods: pre-cooling, post-cooling, and proportional cooling. The optimal configuration can be selected according to the actual steam parameters of the thermal power plant and user needs, thereby improving the system's applicability and economy.

[0036] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered as part of the utility model subject matter of this disclosure, provided that such concepts do not contradict each other.

[0037] The foregoing and other aspects, embodiments, and features of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0038] The accompanying drawings are not drawn to scale according to a true reference numeral. In the drawings, each identical or nearly identical component shown in the various figures can be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0039] Figure 1 This is a schematic diagram of the steam desuperheater structure according to an embodiment of the present utility model;

[0040] Figure 2 This is a schematic diagram of the connection structure of the system front cooling method according to an embodiment of the present utility model;

[0041] Figure 3This is a schematic diagram of the connection structure of the system's post-cooling method according to an embodiment of the present utility model;

[0042] Figure 4 This is a schematic diagram of the connection structure of the proportional cooling method of the system according to an embodiment of the present utility model;

[0043] Figure 5 This is a schematic diagram of the system connection structure of Embodiment 1 of this utility model;

[0044] Figure 6 This is a schematic diagram of the system working fluid flow path in Embodiment 1 of this utility model.

[0045] The meanings of the reference numerals in the figure are as follows:

[0046] 1. Steam desuperheater; 101. Desuperheater body; 1011. Converging tube; 1012. Mixing tube; 1013. Diffuser; 102. Protective shell; 103. Feedwater regulating valve; 104. Connecting pipe; 105. Temperature actuator; 106. Support; 2. Pressure matching device; 201. Inlet chamber; 202. Mixing chamber; 203. Diffuser chamber; 204. Pressure actuator; 3. Medium-pressure steam supply pipe; 4. Exhaust pipe; 5. High-pressure steam supply pipe; 6. Low-pressure steam supply pipe; 7. Pressure transmitter; 8. Temperature sensor; 9. Control unit. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this utility model pertains.

[0048] The terms "first," "second," and similar words used in this utility model patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] This invention addresses the technical problem of resource waste caused by venting steam into the air to ensure the safety of steam turbine equipment, by providing a steam pressure matching system for thermal power plants.

[0050] The steam pressure matching system includes a steam desuperheater 1, a pressure matching device 2, a sensor unit, an actuator unit, a control unit 9, and several matching connecting pipes.

[0051] Among them, the steam desuperheater 1 is a temperature control device that uses demineralized water as the desuperheating medium and adjusts the temperature of high-temperature steam by desuperheating water, including the desuperheater body 101 and the water supply mechanism.

[0052] Among them, such as Figure 1As shown, the desuperheater body 101 includes a tapered converging tube 1011, a mixing tube 1012, and a gradually expanding diffuser tube 1013 connected in sequence. The steam inlet pipe of a conventional desuperheater is generally a straight pipe, while the desuperheater body 101 of this utility model is provided with a tapered transition tapered tube 1011, which, together with the straight mixing tube 1012, can still maintain the design flow rate of steam when the steam flow rate is small, so that the water spray atomization effect is maintained well. The converging tube 1011 has a tapered shape with its diameter gradually decreasing from the front end to the rear end. It has a primary steam inlet at its front end for inputting high-temperature primary steam (such as high-pressure or medium-pressure steam). The mixing tube 1012 is a straight tube with a constant diameter, used to connect the converging tube 1011 and the diffuser tube 1013, serving as the site for heat exchange between the desuperheating water and high-temperature steam. The diffuser tube 1013 is the opposite of the converging tube 1011; its diameter gradually increases from the front end to the rear end, and its length is greater than that of the converging tube 1011. It has a secondary steam outlet at its rear end for outputting secondary steam formed after the high-temperature steam has cooled. A protective shell 102 is fitted over the desuperheater body 1 to protect the internal converging tube 1011, mixing tube 1012, and diffuser tube 1013. A support 106 is provided at the bottom of the protective shell 102 to support the desuperheater body 101.

[0053] The water supply mechanism includes a water supply regulating valve 103 and a connecting pipe 104. The top of the water supply regulating valve 103 is equipped with a temperature actuator 105 electrically connected to it. The temperature actuator 105 is electrically connected to a control unit and is used to adjust the opening degree of the water supply regulating valve 103 according to a control signal. The bottom end of the water supply regulating valve 103 is sealed to the connecting pipe 104 via a flange and has a desuperheating water inlet for desuperheating water intake. A leak-proof sealing section is installed in the regulating part inside the water supply regulating valve 103 to maintain the designed water volume even when the water flow is low, ensuring the steam desuperheater 1 remains in normal operation. The bottom end of the connecting pipe 104 is sealed and inserted into the tapered pipe 1011. A desuperheating water nozzle is provided at the bottom end for spraying desuperheating water into the desuperheater body 1 to mix with the high-temperature steam and cool it down; or a second desuperheating water nozzle is provided, which is connected to the diffuser chamber 203 of the pressure matching device 2 through a pipe to cool the mixed steam in the diffuser chamber 203.

[0054] like Figure 2-4As shown, the pressure matching device 2 includes an inlet chamber 201, a mixing chamber 202, and a diffuser chamber 203 connected in sequence. A steam regulating valve (not shown) is provided between the inlet chamber 201 and the mixing chamber 203. The steam regulating valve is electrically connected to a pressure actuator 204, used to control the opening degree of the steam regulating valve according to a control signal. The inlet chamber 201 has a high-pressure steam inlet for introducing high-temperature, high-pressure steam. The mixing chamber 202 has at least one low-pressure steam inlet, connected to a low-pressure steam supply pipe 6, for introducing low-pressure steam to mix with the high-pressure steam. The diffuser chamber 203 has a medium-pressure steam outlet at its rear end for outputting medium-pressure steam formed by the mixture of high-pressure and low-pressure steam. To ensure the safety of the medium-pressure steam supply pipe 3, an exhaust pipe 4 is connected to it.

[0055] The sensor unit includes a pressure transmitter 7 and a temperature sensor 8 installed on the medium-pressure steam supply pipe 3, which are used to monitor the pressure and temperature of the medium-pressure steam in real time and convert them into 4-20mA or 0-10V standard electrical signals to be transmitted to the control unit.

[0056] The actuator unit includes the temperature actuator 105 and the pressure actuator 204, which respectively receive command signals from the control unit and convert them into mechanical displacement to adjust the opening degree of the water supply regulating valve 103 and the steam regulating valve.

[0057] The control unit 9 employs a distributed control system, such as a DCS control system, including:

[0058] The signal input module is used to receive analog or digital signals from the pressure transmitter 2 and the temperature sensor 1, and to perform filtering and analog-to-digital conversion.

[0059] The control processing unit has a built-in PID algorithm. It compares the preset pressure and temperature setpoints with the feedback values, calculates the deviation, and obtains the control output through proportional, integral, and derivative operations.

[0060] The signal output module is used to convert control commands into 4-20mA or 0-10V analog or digital signals and output them to the temperature actuator and pressure actuator.

[0061] Human-machine interfaces (such as HMIs) are used for parameter setting, status display, and manual intervention;

[0062] The communication interface supports industrial protocols such as Modbus and PROFIBUS, enabling data exchange with plant-level monitoring systems or programmable logic controllers (PLCs).

[0063] The control unit 9 achieves automatic adjustment through closed-loop control. Specifically, the pressure transmitter 7 and the temperature sensor 8 continuously monitor the medium-pressure steam parameters and feed them back to the DCS control system. The DCS control system calculates the control signal through PID based on the deviation between the set value and the actual value, and drives the actuator to adjust the valve opening, thereby accurately controlling the steam pressure and temperature.

[0064] There are at least three ways to connect the steam desuperheater 1 and the pressure matching device 2, depending on the desuperheating medium: front desuperheating, rear desuperheating, and proportional desuperheating.

[0065] Front cooling method, such as Figure 2 As shown, the steam desuperheater 1 is installed in front of the pressure matching device 2, cooling the high-temperature, high-pressure steam before sending it into the pressure matching device 2. At this time, the primary steam inlet of the steam desuperheater 1 is connected to the high-pressure steam supply pipe 5, the secondary steam outlet is connected to the high-pressure steam inlet of the pressure matching device 2 via a secondary steam pipe, and the medium-pressure steam outlet is connected to the medium-pressure steam supply pipe 3. The connecting pipe 104 has only one desuperheating water nozzle extending into the converging pipe 1011.

[0066] A pressure transmitter 7 and a temperature sensor 8 are installed on the medium-pressure steam supply pipe 3 to monitor the medium-pressure steam and temperature in the medium-pressure steam supply pipe 3 in real time. The two are connected to the control unit, and the control unit is also electrically connected to the temperature actuator 105 of the steam desuperheater 1 and the pressure actuator 204 of the pressure matching device 2.

[0067] In this method, the control unit 9 focuses on stabilizing the medium-pressure steam pressure at the outlet of pressure matcher 2 and the steam temperature at the outlet of steam desuperheater 1, i.e., the inlet steam temperature of pressure matcher 2. Pressure transmitter 7 monitors the pressure of medium-pressure steam supply pipe 2 and feeds it back to the DCS control system. The control system compares the measured pressure value with the set value and outputs a control signal to pressure actuator 204 through PID calculation, adjusting the opening of the steam regulating valve of pressure matcher 2, thereby changing the ejector flow rate of high-pressure steam and ultimately stabilizing the pressure of medium-pressure steam. Temperature sensor 8 monitors the medium-pressure steam temperature of positive-pressure steam supply pipe 3 and feeds it back to the DCS control system. The control system compares the measured temperature value with the set value and outputs a control signal to temperature actuator 105 through PID calculation, adjusting the opening of the feedwater regulating valve 103 of steam desuperheater 1, changing the desuperheating water flow rate, thereby precisely controlling the high-pressure steam temperature entering pressure matcher 2 and preventing excessively high temperatures from damaging pressure matcher 2 and subsequent pipelines.

[0068] Post-cooling methods, such as Figure 3As shown, the steam desuperheater 1 is located at the rear of the pressure matching device 2. The high-pressure steam inlet of the pressure matching device 2 is connected to the high-pressure steam supply pipe 5, while the medium-pressure steam outlet is connected to the primary steam inlet of the steam desuperheater 1 through a secondary steam pipe. The secondary steam outlet of the steam desuperheater 1 is connected to the medium-pressure steam supply pipe 3. The pressure transmitter 7 and the temperature sensor 8 are still located on the medium-pressure steam supply pipe 3 and are electrically connected to the control unit. In this configuration, the connecting pipe 104 also has only one desuperheating water nozzle extending into the converging pipe 1011.

[0069] In this method, the control unit focuses on stabilizing the medium-pressure steam temperature at the outlet of pressure matcher 2 and the final steam supply temperature. Pressure transmitter 7 detects the pressure in the medium-pressure steam supply pipe 3 and feeds it back to the DCS control system. The control system compares the measured pressure value with the set value and outputs a control signal to the pressure actuator through PID calculation. This adjusts the opening of the steam regulating valve of pressure matcher 2, changing the injection flow rate of high-pressure steam, thereby stabilizing the medium-pressure steam pressure. The controlled object in this loop is the same as in the front-end desuperheating method. Temperature sensor 8 detects the steam temperature at the outlet of steam desuperheater 1 and feeds it back to the DCS control system. The control system compares the measured temperature value with the set value and outputs a control signal to the temperature actuator 105 through PID calculation. This adjusts the opening of the feed water regulating valve 103 of steam desuperheater 1, changing the desuperheating water flow rate, thereby directly controlling the final externally supplied medium-pressure steam temperature to meet user needs.

[0070] The proportional desuperheating method is used when two water spray desuperheating points are set according to the needs of the working conditions, to simultaneously desuperheat the high-pressure steam entering the pressure matching device 2 and the medium-pressure steam exiting the pressure matching device 2. For example... Figure 4 As shown, similar to the previous desuperheating method, the steam desuperheater 1 is located at the front of the pressure matching. However, the difference is that two desuperheating water nozzles are provided on the water supply mechanism. One nozzle is still located inside the converging tube 1011, and the other nozzle is connected to the diffuser chamber 203 through the desuperheating water pipe to cool the mixed steam inside.

[0071] This method is used in complex operating conditions where simultaneous and reverse temperature control of steam at two locations is required. The control unit needs to coordinate the water distribution at the two desuperheating points, with the focus being on stabilizing the pressure of the medium-pressure steam and the final steam supply temperature.

[0072] Similar to the two methods mentioned above, the medium-pressure steam pressure is stabilized by adjusting the overall regulating valve opening of the pressure matching device 2.

[0073] The temperature control loop is a complex loop with feedforward-feedback load control. Temperature sensor 8 detects the temperature of the final medium-pressure steam and feeds it back to the DCS control system as the main control signal. Based on this temperature deviation, the control system obtains the total desuperheating water demand through PID control and distributes the total water volume to two actuators (or one actuator drives two regulating mechanisms) according to a preset proportional relationship or a feedforward signal calculated based on the high-pressure steam flow / temperature. These actuators control the opening of the water supply regulating valves 103 at the two desuperheating points, respectively. This prevents the high-pressure steam temperature from being too high and damaging the pressure matching device 2, while ensuring that the final outlet medium-pressure steam temperature accurately meets the standard.

[0074] Example 1

[0075] This embodiment takes a steam supply system applied to a thermal power plant as an example to explain in detail the purpose and beneficial effects of the technical solution of this utility model.

[0076] The plant currently has two 130t / h high-temperature and ultra-high-pressure coal-fired boilers, equipped with an 18MW extraction back turbine generator set.

[0077] like Figure 5-6 As shown, the system includes a newly installed pressure matching device. The high-pressure steam inlet of this device is connected to the plant's high-pressure steam supply pipe via pipelines and regulating valves. The operating parameters of the high-pressure steam are 9-11 MPa (absolute pressure). A steam desuperheater is installed on the pipeline connecting the high-pressure steam inlet to the high-pressure steam header. The low-pressure steam inlet of the pressure matching device is connected to the turbine unit's low-pressure exhaust header via pipelines and regulating valves. The parameters of the low-pressure steam are 0.7-0.8 MPa (gauge pressure). The outlet of the pressure matching device is connected to the plant's medium-pressure steam supply pipe via pipelines.

[0078] During the non-heating season, when the consumption of low-pressure external steam by users drops to 12 t / h, causing the low-pressure exhaust pressure of the steam turbine unit to rise above 1.0 MPa (gauge pressure) and endanger safe operation, this system will be activated. The specific operation is as follows: Open the regulating valve on the high-pressure steam pipeline to introduce high-pressure steam at approximately 10 MPa and a flow rate of approximately 26 t / h as the working steam source; simultaneously, open the regulating valve on the low-pressure steam pipeline to introduce low-pressure steam at approximately 0.98 MPa and a flow rate of approximately 10 t / h as the induced absorption steam. The two steam streams mix in the pressure matching device, induced to generate medium-pressure steam at a pressure of 2.5 MPa (absolute pressure) and a flow rate of approximately 41 t / h, which is then delivered to the medium-pressure steam supply pipeline. To control the outlet steam temperature, approximately 5 t / h of desuperheating water can be injected into the mixed steam simultaneously.

[0079] In the system, pressure transmitters and temperature sensors detect the pressure and temperature of the medium-pressure steam supply pipe in real time and transmit the signals to the DCS control system. The control system performs calculations based on preset PID parameters such as proportional band, integral time, and derivative time, and outputs control signals to the temperature actuator and pressure actuator to automatically adjust the desuperheating water flow and the opening of the steam valve, thereby achieving stable control of steam parameters.

[0080] By putting this system into operation, the steam extraction capacity of the low-pressure exhaust pipeline was effectively increased, successfully stabilizing the low-pressure exhaust pressure within the rated safe range and avoiding energy waste caused by safety valve activation and venting to the air. Simultaneously, due to the increased flow rate in the medium-pressure steam supply pipeline, the medium-pressure dual-pressure reduction device originally used for desuperheating and pressure reduction could be taken out of operation during the commissioning of this system, further reducing plant power consumption and achieving both safety and economic benefits.

[0081] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. A steam pressure matching system for a thermal power plant, characterized in that, include: Steam desuperheater (1), pressure matching device (2), sensor unit, actuator unit and control unit (9); The steam desuperheater (1) includes a desuperheater body (101) and a water supply mechanism. The front end and rear end of the desuperheater body (101) are respectively provided with a primary steam inlet and a secondary steam outlet. The water supply mechanism is connected to the desuperheater body (101) and is provided with at least one desuperheating water inlet. The pressure matching device (2) includes an inlet chamber (201), a mixing chamber (202), and a diffuser chamber (203) connected in sequence. The inlet chamber (201) is provided with a high-pressure steam inlet, which is connected to the secondary steam outlet or the high-pressure steam supply pipe (5). The mixing chamber (202) is provided with at least one low-pressure steam inlet. The diffuser chamber (203) is provided with a medium-pressure steam outlet at its rear end, which is connected to the medium-pressure steam supply pipe (3) or the primary steam inlet. The sensor unit is installed on the medium-pressure steam supply pipe (3) and is used to monitor the medium-pressure steam state parameters in the medium-pressure steam supply pipe (3) in real time. The actuator unit is located on the pressure matching device (2) and / or the water supply mechanism, and is used to drive and control the steam pressure of the pressure matching device (2) or the steam temperature of the steam desuperheater (1). The control unit is electrically connected to the sensor unit and the actuator unit.

2. The steam pressure matching system for a thermal power plant according to claim 1, characterized in that, The desuperheater body (101) is provided with a converging tube (1011), a mixing tube (1012) and a diffuser tube (1013) connected in sequence. The front end of the converging tube (1011) is the primary steam inlet, and the rear end of the diffuser tube (1013) is the secondary steam outlet. The water supply mechanism includes a water supply regulating valve and a connecting pipe. One end of the connecting pipe (104) is connected to the water supply regulating valve (103), and the other end is provided with at least one desuperheating water nozzle. One of the desuperheating water nozzles extends into the converging pipe (1011), and the other desuperheating water nozzle is either connected to the diffuser chamber (203) or closed.

3. The steam pressure matching system for a thermal power plant according to claim 2, characterized in that, The actuator unit includes a temperature actuator (105) located at the top of the water supply regulating valve (103), and the temperature actuator (105) is electrically connected to the water supply regulating valve (103) and the control unit (9). The sensor unit includes a temperature sensor (8), which is electrically connected to the control unit (9) and is used to monitor the temperature of the medium-pressure steam in real time.

4. The steam pressure matching system for a thermal power plant according to claim 3, characterized in that, A steam regulating valve is provided between the air intake chamber (201) and the mixing chamber (202); The actuator unit includes a pressure actuator (204), which is electrically connected to the steam regulating valve and the control unit (9); The sensor unit includes a pressure transmitter (7), which is electrically connected to the control unit (9) and is used to monitor the pressure of the medium-pressure steam in real time.

5. The steam pressure matching system for a thermal power plant according to claim 2, characterized in that, The steam desuperheater (1) is located in front of the pressure matching device (2). The primary steam inlet is connected to the high-pressure steam supply pipe (5), and the secondary steam outlet is connected to the high-pressure steam inlet. Meanwhile, the medium-pressure steam outlet is connected to the medium-pressure steam supply pipe (3). The connecting pipe (104) has only one desuperheating water nozzle that extends into the tapered pipe (1011).

6. The steam pressure matching system for a thermal power plant according to claim 2, characterized in that, The steam desuperheater (1) is located at the rear of the pressure matching device (2). The primary steam inlet is connected to the medium-pressure steam outlet, and the secondary steam outlet is connected to the medium-pressure steam supply pipe (3). Meanwhile, the high-pressure steam inlet is connected to the high-pressure steam supply pipe (5). The connecting pipe (104) has only one desuperheating water nozzle that extends into the tapered pipe (1011).

7. The steam pressure matching system for a thermal power plant according to claim 2, characterized in that, The steam desuperheater (1) is located in front of the pressure matching device (2). The primary steam inlet is connected to the high-pressure steam supply pipe (5), and the secondary steam outlet is connected to the high-pressure steam inlet. Meanwhile, the medium-pressure steam outlet is connected to the medium-pressure steam supply pipe (3). The connecting pipe (104) is provided with two desuperheating water nozzles, one of which extends into the converging pipe (1011), and the other of which is connected to the diffuser chamber (203).

8. The steam pressure matching system for a thermal power plant according to claim 4, characterized in that, The control unit (9) is a distributed control system, including: A signal input module is used to receive signals from the pressure transmitter (7) and the temperature sensor (8); The control processing unit is used to run the PID control algorithm and generate control commands. The signal output module is used to send the control commands to the temperature actuator (105) and the pressure actuator (204).

9. The steam pressure matching system for a thermal power plant according to claim 1, characterized in that, The medium-pressure steam supply pipe (3) is also connected to the exhaust pipe (4).

Images