Wide-load efficient coal power unit thermodynamic system

Abstract

The utility model relates to a wide-load efficient thermodynamic system of a coal power unit. The wide-load efficient coal power unit thermodynamic system comprises a front high-pressure cylinder and a rear high-pressure cylinder. The front steam admission amount and the front through-flow area of the front high-pressure cylinder are smaller than the rear steam admission amount and the rear through-flow area of the rear high-pressure cylinder, and the steam admission amount sum of the front steam admission amount and the rear steam admission amount meets the rated working condition use requirement of the wide-load efficient coal power unit thermodynamic system. A first valve is arranged on a first main steam transmission branch where the front high-pressure cylinder is connected with the main steam transmission pipeline, a second valve is arranged on a second main steam transmission branch where the rear high-pressure cylinder is connected with the main steam transmission pipeline, and a third valve is arranged on a first steam exhaust pipeline where the front high-pressure cylinder is connected with the rear high-pressure cylinder. The connection state comprises a series connection state and a parallel connection state, and the wide-load operation efficiency of the wide-load efficient coal power unit thermodynamic system can be effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of generator set, in particular to a wide load high -efficient coal electric machine group thermodynamic system. BACKGROUND

[0002] Coal electric machine group power generation is a complex energy conversion process, involves the mutual transformation of multiple energy forms. Among them, the steam turbine in the wide load high -efficient coal electric machine group thermodynamic system is an important link for the coal electric machine group to realize energy conversion, and its operation efficiency and performance directly affect the overall efficiency and performance of the coal electric machine group. The cylinder of the steam turbine can be divided into high -pressure cylinder, medium -pressure cylinder and low -pressure cylinder according to different inlet steam parameters. Among them, the high -pressure cylinder is located at the front of the steam turbine, and it is the first stage of the main steam into the cylinder, and the high -pressure cylinder exhaust enters the boiler reheater and then enters the medium -pressure cylinder to work.

[0003] When the traditional unit is built, usually multiple power generation is the goal, so the high -pressure cylinder of the steam turbine is usually designed with rated working condition as the design benchmark, but with the development of new energy and the construction of new power system, coal power gradually changes to regulatory and security power supply, and large inlet steam volume ultra -supercritical unit is generally in medium -low load operation, and cannot fully exert the advantage of high efficiency at rated load. Therefore, how to improve the operation efficiency of the high -pressure cylinder of the steam turbine under various load conditions to improve the wide load high efficiency of the whole unit is the problem to be solved at present. UTILITY MODEL CONTENTS

[0004] Therefore, it is necessary to provide a wide load high -efficient coal electric machine group thermodynamic system for the problem that the high -pressure cylinder of the steam turbine cannot be efficiently operated under medium -low load.

[0005] A wide load high -efficient coal electric machine group thermodynamic system, the wide load high -efficient coal electric machine group thermodynamic system includes: front high -pressure cylinder and rear high -pressure cylinder;

[0006] The front inlet steam volume and the front flow area of the front high -pressure cylinder are less than the rear inlet steam volume and the rear flow area of the rear high -pressure cylinder, and the total inlet steam volume of the front inlet steam volume and the rear inlet steam volume meets the rated working condition use demand of the wide load high -efficient coal electric machine group thermodynamic system;

[0007] The front inlet steam port of the front high -pressure cylinder is connected with the main steam transmission pipeline of the wide load high -efficient coal electric machine group thermodynamic system through a first main steam transmission branch, the rear first inlet steam port of the rear high -pressure cylinder is connected with the main steam transmission pipeline through a second main steam transmission branch, and the front first exhaust port of the front high -pressure cylinder is connected with the rear second inlet steam port of the rear high -pressure cylinder through a first exhaust pipeline;

[0008] The first main steam transmission branch is provided with a first valve, the second main steam transmission branch is provided with a second valve, and the first exhaust pipe is provided with a third valve, the first valve, the second valve and the third valve are used for adjusting the connection state of the front high-pressure cylinder and the rear high-pressure cylinder, and the connection state includes a series state and a parallel state.

[0009] In one of the embodiments, the wide-load high-efficiency coal-fired unit thermal system further comprises a boiler and a high-pressure heating assembly connected with the boiler.

[0010] The high-pressure heating assembly is used for extracting high-pressure exhaust steam from the front high-pressure cylinder and the rear high-pressure cylinder to heat the feed water entering the boiler.

[0011] The front second exhaust port of the front high-pressure cylinder is connected with the high-pressure heating assembly through a front steam extraction pipe.

[0012] The rear first exhaust port of the rear high-pressure cylinder is connected with the high-pressure heating assembly through a rear steam extraction pipe.

[0013] In one of the embodiments, the boiler comprises a superheating assembly and a reheating assembly, and the wide-load high-efficiency coal-fired unit thermal system further comprises a medium-pressure cylinder.

[0014] The main steam outlet of the superheating assembly is connected with the main steam transmission pipe, and the feed water inlet is connected with the assembly water outlet of the high-pressure heating assembly through a first feed water pipe.

[0015] The steam inlet of the reheating assembly is connected with a high-pressure exhaust steam transmission pipe, and the high-pressure exhaust steam transmission pipe is connected with the rear steam extraction pipe through a second exhaust pipe.

[0016] The reheated steam outlet of the reheating assembly is connected with the reheated steam inlet of the medium-pressure cylinder through a reheated steam transmission pipe.

[0017] In one of the embodiments, the intermediate stage steam inlet of the rear high-pressure cylinder is connected with the front steam extraction pipe through a third exhaust pipe.

[0018] The third exhaust pipe is provided with a fourth valve for controlling the on-off of the third exhaust pipe.

[0019] In one of the embodiments, the front steam extraction pipe is connected with the high-pressure exhaust steam transmission pipe through a third exhaust pipe, and the third exhaust pipe is provided with a fourth valve for controlling the on-off of the third exhaust pipe.

[0020] In one of the embodiments, the high-pressure heating assembly comprises a first high-pressure heater and a second high-pressure heater.

[0021] The first feedwater outlet of the first high-pressure heater is connected with the boiler through a first feedwater pipeline, and the first feedwater inlet of the first high-pressure heater is connected with the second feedwater outlet of the second high-pressure heater through a third feedwater pipeline.

[0022] The extraction steam temperature of the first high-pressure heater is greater than the extraction steam temperature of the second high-pressure heater.

[0023] In one of the embodiments, the front second steam outlet of the front high-pressure cylinder is connected with the first high-pressure heater and the second high-pressure heater through the front extraction pipeline respectively.

[0024] The rear first steam outlet of the rear high-pressure cylinder is connected with the first high-pressure heater and the second high-pressure heater through the rear extraction pipeline respectively.

[0025] In one of the embodiments, the front second steam outlet of the front high-pressure cylinder is connected with the first high-pressure heater through the front extraction pipeline.

[0026] The rear first steam outlet of the rear high-pressure cylinder is connected with the second high-pressure heater through the rear extraction pipeline.

[0027] In one of the embodiments, the front second steam outlet of the front high-pressure cylinder is connected with the second high-pressure heater through the front extraction pipeline.

[0028] The rear first steam outlet of the rear high-pressure cylinder is connected with the first high-pressure heater through the rear extraction pipeline.

[0029] In one of the embodiments, the first valve is a regulating valve, and the second valve and the third valve are stop valves.

[0030] The above wide-load high-efficiency coal-fired unit thermal system is provided with two high-pressure cylinders, i.e., a front high-pressure cylinder and a rear high-pressure cylinder, a first valve is arranged on a first main steam transmission branch connected between the front high-pressure cylinder and a main steam transmission pipeline, a second valve is arranged on a second main steam transmission branch connected between the rear high-pressure cylinder and the main steam transmission pipeline, and a third valve is arranged on a first exhaust steam pipeline connected between the front high-pressure cylinder and the rear high-pressure cylinder, so that the connection state of the front high-pressure cylinder and the rear high-pressure cylinder can be adjusted through the first valve, the second valve and the third valve. Therefore, when the operation condition of the wide-load high-efficiency coal-fired unit thermal system is a rated condition, the valves can be adjusted to make the front high-pressure cylinder and the rear high-pressure cylinder in a parallel state, so as to meet the rated condition use requirement of the wide-load high-efficiency coal-fired unit thermal system. In the case where the operation condition of the wide-load high-efficiency coal-fired unit thermal system is not a rated condition, on the one hand, since the front admission amount of the front high-pressure cylinder is less than the rear admission amount of the rear high-pressure cylinder, the steam flowing into the front high-pressure cylinder can be adjusted, so as to realize high-efficiency operation of the front high-pressure cylinder and the rear high-pressure cylinder. On the other hand, since the front flow area of the front high-pressure cylinder is less than the rear flow area of the rear high-pressure cylinder, the connection state of the front high-pressure cylinder and the rear high-pressure cylinder can be adjusted to a series state, so that the front high-pressure cylinder can play a role of pressure holding, the steam pressure entering the front high-pressure cylinder is increased, and the energy conversion efficiency of the front high-pressure cylinder and the rear high-pressure cylinder is increased, so that the wide-load high-efficiency of the wide-load high-efficiency coal-fired unit thermal system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the wide-load high-efficiency coal-fired unit thermal system in an embodiment;

[0032] Figure 2 It is a structural schematic diagram of the wide-load high-efficiency coal-fired unit thermal system in another embodiment;

[0033] Figure 3 It is a structural schematic diagram of the wide-load high-efficiency coal-fired unit thermal system in another embodiment;

[0034] Figure 4 It is a structural schematic diagram of the wide-load high-efficiency coal-fired unit thermal system in another embodiment;

[0035] Figure 5 It is a structural schematic diagram of the wide-load high-efficiency coal-fired unit thermal system in another embodiment.

[0036] BRIEF DESCRIPTION OF DRAWINGS:

[0037] Preceding high-pressure cylinder-101; succeeding high-pressure cylinder-102; main steam transmission pipeline-103; first main steam transmission branch-1012; second main steam transmission branch-1022; preceding first exhaust port-1013; first exhaust steam pipeline-1014; succeeding second steam inlet-1027; first valve-1015; second valve-1024; third valve-1016; boiler-104; high-pressure heating assembly-105; preceding steam extraction pipeline-1018; succeeding steam extraction pipeline-1026; superheating assembly-1041; feed water inlet-10412; reheat assembly-1042; steam inlet-10421; reheat steam outlet-10422; high-pressure exhaust steam transmission pipeline-10423; first feed water pipeline-1043; assembly water outlet-1051; reheat steam transmission pipeline-1044; medium-pressure cylinder-106; reheat steam inlet-1061; third exhaust steam pipeline-1019; fourth valve-10110; wide-load high-efficiency coal-fired unit thermal system-500; first high-pressure heater-1053; second high-pressure heater-1054; first feed water outlet-10531; first feed water inlet-10532; second feed water inlet-10541; second feed water outlet-10542; third feed water pipeline-10543. DETAILED DESCRIPTION

[0038] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of ways beyond the specific embodiments described and claimed herein. It is therefore intended that the present application not be limited in scope to the specific embodiments disclosed but rather that the scope of the present application be measured by the breadth of the claims hereinafter.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0042] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0044] In one embodiment, the turbine in a conventional wide-load, high-efficiency coal-fired power unit thermal system typically has only one high-pressure cylinder. During operation, the boiler transfers the heat energy generated by coal combustion to water, producing high-temperature, high-pressure main steam. After exiting the boiler, the main steam enters the single high-pressure cylinder through the main steam transmission pipeline. Inside the high-pressure cylinder, the steam expands and performs work, driving the turbine rotor.

[0045] Because traditional wide-load high-efficiency coal-fired power units are typically built with the goal of maximizing power generation, the high-pressure cylinder of the turbine is usually designed based on the rated operating conditions. This means that the high-pressure cylinder in a traditional turbine can only maintain high-efficiency energy conversion under rated operating conditions. Under medium and low load conditions, the main steam parameters and steam inlet flow rate generated by the wide-load high-efficiency coal-fired power unit's thermal system are different, and the steam inlet flow rate of the high-pressure cylinder does not match the design value, which will lead to a decrease in the energy conversion efficiency of the high-pressure cylinder.

[0046] In order to improve the operating efficiency of the high-pressure cylinder of the steam turbine under various load conditions, and thus improve the overall high efficiency of the unit under wide load conditions, such as Figure 1 As shown, this application provides a wide-load high-efficiency coal-fired power unit thermal system. The turbine of the wide-load high-efficiency coal-fired power unit thermal system includes a front high-pressure cylinder 101 and a rear high-pressure cylinder 102.

[0047] The front steam inlet volume and front flow area of ​​the front high-pressure cylinder 101 are smaller than the rear steam inlet volume and rear flow area of ​​the rear high-pressure cylinder 102. The total steam inlet volume of the front and rear cylinders meets the rated operating conditions of the thermal system of the wide-load high-efficiency coal-fired power unit.

[0048] The front air inlet 1011 of the front high-pressure cylinder 101 is connected to the main steam transmission pipeline 103 of the thermal system of the wide-load high-efficiency coal-fired power unit via the first main steam transmission branch 1012. The rear first steam inlet 1021 of the rear high-pressure cylinder 102 is connected to the main steam transmission pipeline 103 via the second main steam transmission branch 1022, and the front first exhaust port 1013 of the front high-pressure cylinder 101 is connected to the rear second steam inlet 1023 of the rear high-pressure cylinder 102 via the first exhaust pipeline 1014.

[0049] The first main steam transmission branch 1012 is equipped with a first valve 1015, the second main steam transmission branch 1022 is equipped with a second valve 1024, and the first exhaust pipe 1014 is equipped with a third valve 1016.

[0050] In one embodiment, the first valve 1015, the second valve 1024, and the third valve 1016 are all shut-off valves, that is, valves with only two states: open and closed. They can only be used to control the opening and closing of the corresponding pipeline, but cannot regulate the flow rate of the pipeline.

[0051] In one embodiment, the first valve 1015 is a regulating valve, and the second valve 1024 and the third valve 1016 are both shut-off valves. The steam flow rate of the first main steam transmission branch 1012 can be adjusted by controlling the opening degree of the first valve 1015. By setting the first valve 1015 as a regulating valve, the steam flow rate of the first main steam transmission branch 1012 can be adjusted. Thus, under low operating load conditions, the steam flow rate of the front high-pressure cylinder can be reduced, while the steam flow rate of the rear high-pressure cylinder can be increased, thereby improving the energy conversion efficiency of the rear high-pressure cylinder.

[0052] The "front steam inlet volume" of the front high-pressure cylinder 101 refers to the designed steam inlet volume of the front high-pressure cylinder 101, that is, the amount of steam required to pass through the front high-pressure cylinder 101 when it reaches its optimal energy conversion efficiency. The "rear steam inlet volume" of the rear high-pressure cylinder 102 refers to the designed steam inlet volume of the rear high-pressure cylinder 102, that is, the amount of steam required to pass through the rear high-pressure cylinder 102 when it reaches its optimal energy conversion efficiency.

[0053] The requirement that the total steam intake of the pre-inlet and post-inlet steam volumes meet the rated operating requirements of the thermal system of the wide-load high-efficiency coal-fired power unit means that, when the thermal system operates under rated conditions, the pre-high-pressure cylinder 101 and the post-high-pressure cylinder 102 can receive all the main steam generated by the boiler of the wide-load high-efficiency coal-fired power unit. When designing the thermal system, ensuring that the total steam intake of the pre-inlet and post-inlet steam volumes meets the rated operating requirements of the thermal system guarantees the energy conversion efficiency of the thermal system under rated conditions. Understandably, the specific design schemes for the pre-inlet and post-inlet steam volumes can be determined based on the actual operating conditions of the thermal system of the wide-load high-efficiency coal-fired power unit.

[0054] In one embodiment, the relationship between the pre-intake steam volume and the post-intake steam volume is represented by a ratio. Different dual-high-pressure cylinder steam intake ratios can be designed based on the duration of low- and medium-load operation of the coal-fired power unit in its location. For example, if the unit actually operates at 40% load for a long time, the dual-high-pressure cylinder ratio can be set to 4:6, meaning the pre-intake steam volume is 40% of the total main steam produced by the unit under rated conditions, and the post-intake steam volume is 60% of the total main steam produced by the unit under rated conditions. As another example, if the unit actually operates at 30% load for a long time, the dual-high-pressure cylinder ratio can be set to 3:7, meaning the pre-intake steam volume is 30% of the total main steam produced by the unit under rated conditions, and the post-intake steam volume is 70% of the total main steam produced by the unit under rated conditions. And so on. The steam intake ratio of the pre-intake steam volume to the post-intake steam volume can be 1:9, 2:8, 3:7, 4:6, etc.

[0055] The flow area refers to the channel area of ​​the steam flow passage inside the high-pressure cylinder, which can characterize the flow velocity and flow rate of steam in the high-pressure cylinder. By making the flow area of ​​the front high-pressure cylinder 101 smaller than that of the rear high-pressure cylinder 102, when the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are connected in series, the main steam will first enter the front high-pressure cylinder 101, then exit from the front high-pressure cylinder 101 and enter the rear high-pressure cylinder 102. Since the front high-pressure cylinder 101 has a lower flow area, the main steam pressure in the main steam transmission pipeline 103 can be increased, that is, the main steam pressure is increased by pressure buildup. After the pressurized main steam flows into the front high-pressure cylinder 101 to do work, the main steam pressure decreases and then enters the rear high-pressure cylinder 102 to do work. For example, if the original main steam pressure is 22 MPa, with the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 connected in series, the main steam pressure can be increased to 28 MPa due to the low flow area of ​​the front high-pressure cylinder 101. After the main steam enters the front high-pressure cylinder 101 to do work, the exhaust pressure of the front high-pressure cylinder 101 will decrease back to 22 MPa and be input to the rear high-pressure cylinder 102 to do work. From the perspective of the operation of the rear high-pressure cylinder 102, the steam pressure entering the rear high-pressure cylinder 102 is 22 MPa regardless of the presence of the front high-pressure cylinder 101, and the energy conversion efficiency of the rear high-pressure cylinder 102 will not change. However, without the front high-pressure cylinder 101, the high-pressure energy conversion efficiency is only the energy conversion efficiency of the rear high-pressure cylinder 102 alone. With the front high-pressure cylinder 101 installed, the energy conversion efficiency of the rear high-pressure cylinder 102 will not change, while the front high-pressure cylinder 101 will also operate efficiently, which can improve the overall energy conversion efficiency of the thermal system of the wide-load high-efficiency coal-fired power unit. The installation of the front-mounted high-pressure cylinder 101 can effectively improve the initial parameters of the main steam circulation, thereby improving the overall energy conversion efficiency of the thermal system of the wide-load high-efficiency coal-fired power unit.

[0056] The main steam transmission pipeline 103 is a gas transmission pipeline used to transmit main steam. The steam inlet of the main steam transmission pipeline 103 can be connected to the main steam generation source in the thermal system of a wide-load, high-efficiency coal-fired power unit, such as a boiler, to receive the main steam generated by the boiler. The first main steam transmission branch 1012 is a steam transmission pipeline used to transmit main steam to the pre-pressure cylinder 101. The pre-pressure cylinder 101's front steam inlet 1011 can be connected to the main steam transmission pipeline through the first main steam transmission branch 1012, allowing the main steam to be transmitted to the pre-pressure cylinder 101 for energy conversion. The second main steam transmission branch 1022 is a steam transmission pipeline used to transmit main steam to the rear high-pressure cylinder 102. The rear first steam inlet 1021 of the rear high-pressure cylinder 102 can be connected to the main steam transmission pipeline 103 through the second main steam transmission branch 1022, allowing the main steam to be transmitted to the rear high-pressure cylinder 102 for energy conversion.

[0057] A first exhaust pipe 1014 is provided between the front high-pressure cylinder 101 and the rear high-pressure cylinder 102. The front first exhaust port 1013 can be connected to the rear second exhaust port 1027 of the rear high-pressure cylinder 102 through the first exhaust pipe 1014. By providing a connecting pipe between the front high-pressure cylinder 101 and the rear high-pressure cylinder 102, it is possible to construct a series structure of the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 under corresponding operating conditions.

[0058] The first main steam transmission branch 1012 is equipped with a first valve 1015, the second main steam transmission branch 1022 is equipped with a second valve 1024, and the first exhaust pipe is equipped with a third valve 1016. Figure 1 It can be seen that when the first valve 1015 and the second valve 1024 are open, and the third valve 1016 is closed, the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are connected in parallel, and the main steam can enter the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 respectively. When the first valve 1015 and the third valve 1016 are open, and the second valve 1024 is closed, the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are connected in series. The main steam will first enter the front high-pressure cylinder 101, and after the front high-pressure cylinder 101 performs work, it will be discharged into the rear high-pressure cylinder 102 to continue performing work.

[0059] Specifically, taking a 3:7 ratio of the steam inlet flow rate of the front high-pressure cylinder 101 to the rear high-pressure cylinder 102 as an example, the operating conditions of the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 under different load conditions are illustrated. When the thermal system of a wide-load, high-efficiency coal-fired power unit is operating at its rated condition, the first valve 1015 and the second valve 1024 can be opened, and the third valve 1016 can be closed. At this time, the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are in parallel, with main steam entering both cylinders. The steam inlet flow rate of the front high-pressure cylinder 101 is 30%, and the steam inlet flow rate of the rear high-pressure cylinder 102 is 70%, allowing both high-pressure cylinders to achieve optimal energy conversion efficiency. When the thermal system of a wide-load high-efficiency coal-fired power unit is operating within the 70%-100% load range, the first valve 1015 and the second valve 1024 are kept open, while the third valve 1016 is closed, so that the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are in parallel. When the first valve 1015 is a regulating valve, the target opening degree of the first valve 1015 can be determined according to the load difference between the operating conditions and the matching load of the rear valve. The first valve 1015 is adjusted to the corresponding target opening degree. At this time, the steam intake of the front high-pressure cylinder 101 is reduced compared to the rated operating conditions, while the steam intake of the rear high-pressure cylinder 102 remains unchanged.

[0060] When the thermal system of a wide-load, high-efficiency coal-fired power unit is operating at or below 70% load, the second valve 1024 can be closed. The first valve 1015 and the third valve 1016 are then opened. At this time, the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are in series. The main steam can only enter the front high-pressure cylinder 101 first. Because the flow area of ​​the front high-pressure cylinder 101 is relatively low, the pressure of the main steam before entering the front high-pressure cylinder 101 is increased by pressure buildup. The high-pressure main steam enters the front high-pressure cylinder 101, performs work, and is then depressurized and discharged. The exhaust steam from the front high-pressure cylinder 101 continues to enter the rear high-pressure cylinder 102 to perform work. Taking a 70% load condition as an example, the original main steam pressure at 70% load is 22MPa. The main steam pressure can be increased to 28MPa. After the front high-pressure cylinder 101 performs work, the exhaust pressure is 22MPa and enters the rear high-pressure cylinder 102. At this time, the exhaust pressure entering the rear high-pressure cylinder 102 is consistent with the steam pressure when the main steam is directly input into the rear high-pressure cylinder 102 through the second main steam transmission branch 1022. Therefore, the problem of the energy conversion efficiency of the rear high-pressure cylinder 102 being affected by the reduction of the steam inlet pressure of the rear high-pressure cylinder 102 due to the setting of the front high-pressure cylinder 101 will not occur.

[0061] In the above embodiments, the turbine of the generator set's thermal system is equipped with two high-pressure cylinders: a front high-pressure cylinder and a rear high-pressure cylinder. A first valve is installed on the first main steam transmission branch connecting the front high-pressure cylinder to the main steam transmission pipeline, a second valve is installed on the second main steam transmission branch connecting the rear high-pressure cylinder to the main steam transmission pipeline, and a third valve is installed on the first exhaust pipe connecting the front and rear high-pressure cylinders. The connection state of the front and rear high-pressure cylinders can be adjusted using the first, second, and third valves. Therefore, when the thermal system of the wide-load high-efficiency coal-fired power unit is operating at its rated condition, the valves can be adjusted to connect the front and rear high-pressure cylinders in parallel, meeting the rated operating requirements of the thermal system. When the thermal system of the wide-load high-efficiency coal-fired power unit is not operating at its rated condition, on the one hand, since the front steam inlet of the front high-pressure cylinder is less than the rear steam inlet of the rear high-pressure cylinder, the proportion of steam flowing into the front high-pressure cylinder can be adjusted to achieve efficient operation of both the front and rear high-pressure cylinders. On the other hand, since the front flow area of ​​the front high-pressure cylinder is smaller than the rear flow area of ​​the rear high-pressure cylinder, the connection state of the front high-pressure cylinder and the rear high-pressure cylinder can be adjusted to a series state, so that the front high-pressure cylinder can play a pressure-blocking role, increase the steam pressure entering the front high-pressure cylinder, and thus improve the energy conversion efficiency of the front high-pressure cylinder and the rear high-pressure cylinder together.

[0062] In one embodiment, such as Figure 2As shown, the thermal system of the wide-load high-efficiency coal-fired power unit also includes a boiler 104 and a high-pressure heating component 105 connected to the boiler 104.

[0063] The high-pressure heating assembly 105 is used to extract high-pressure exhaust steam from the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 to heat the feedwater entering the boiler 104.

[0064] The front second exhaust port 1017 of the front high-pressure cylinder 101 is connected to the high-pressure heating assembly 105 through the front extraction steam pipe 1018. The rear first exhaust port 1025 of the rear high-pressure cylinder 102 is connected to the high-pressure heating assembly 105 through the rear extraction steam pipe 1026.

[0065] In the thermal system of the wide-load high-efficiency coal-fired power unit, the boiler 104 is a device used to convert the chemical energy of fuel into thermal energy, and then generate steam for power generation. The high-pressure heating component 105 uses steam extracted from the steam turbine to heat the feedwater of the boiler 104, thereby increasing the feedwater temperature entering the boiler 104.

[0066] Specifically, both the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are connected to the high-pressure heating component 105. When the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 perform energy conversion and work through the incoming steam, the high-pressure heating component 105 can extract high-temperature and high-pressure steam from the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 respectively to heat the feedwater. Then, the heated feedwater is input into the boiler 104 for energy conversion, thereby constructing a high-pressure steam regenerative cycle.

[0067] In the above embodiments, by connecting the front high-pressure cylinder and the rear high-pressure cylinder to the high-pressure heating component, the exhaust steam of the front high-pressure cylinder and the rear high-pressure cylinder can be reused in the high-pressure heating component, which effectively reduces fuel consumption in the power generation process, improves the cycle efficiency of the thermal system, and helps to improve the thermal efficiency of the entire unit.

[0068] In one embodiment, such as Figure 3 As shown,

[0069] The thermal system of the wide-load high-efficiency coal-fired power unit also includes an intermediate-pressure cylinder 106, and the boiler 104 includes a superheating assembly 1041 and a reheating assembly 1042.

[0070] The main steam outlet 10411 of the superheating component 1041 is connected to the main steam transmission pipeline 103 to generate main steam and input the main steam into the main steam transmission pipeline 103. The water inlet 10412 of the superheating component 1041 is connected to the component outlet 1051 of the high-pressure heating component 105 through the first water supply pipeline 1043.

[0071] The steam inlet 10421 of the reheat assembly 1042 is connected to the high-pressure exhaust transmission pipeline 10423, which in turn is connected to the downstream extraction pipeline 1026 via the second exhaust pipeline 1027. The reheat steam outlet 10422 of the reheat assembly 1042 is connected to the reheat steam inlet 1061 of the intermediate-pressure cylinder 106 via the reheat steam delivery pipeline 1044. The reheat assembly 1042 receives a portion of the high-pressure exhaust from the downstream high-pressure cylinder 102, reheats this portion to form reheat steam, and then delivers the reheat steam to the intermediate-pressure cylinder 106 via the reheat steam delivery pipeline 1044 for circulation and work.

[0072] In one embodiment, after the intermediate-pressure cylinder performs work using reheat steam, it discharges intermediate-pressure exhaust steam. A portion of this exhaust steam can be transported via an intermediate-pressure exhaust steam pipeline to the low-pressure cylinder of the wide-load, high-efficiency coal-fired power unit's thermal system for further work. The exhaust steam from the low-pressure cylinder, after performing work, enters the condenser for exhaust steam cooling, resulting in condensate at the same pressure, which is then used as feedwater for further heating and circulation. A portion of the intermediate-pressure exhaust steam from the intermediate-pressure cylinder can then enter the third high-pressure heater and the deaerator. The third high-pressure heater utilizes the heat carried by the intermediate-pressure exhaust steam to reheat the feedwater, and then inputs the heated feedwater into the high-pressure heating components. The deaerator removes dissolved oxygen and other non-condensable gases from the feedwater. The feedwater exiting the deaerator is pressurized by a water pump to a pressure slightly higher than the boiler's main steam pressure before entering the third high-pressure heater.

[0073] In the above embodiments, by connecting the superheating component, reheating component, intermediate pressure cylinder with the front high pressure cylinder, rear high pressure cylinder and high pressure heating component, a regenerative cycle can be achieved for the thermal system of wide-load high-efficiency coal-fired power units, thereby improving the cycle thermal efficiency of the thermal system of wide-load high-efficiency coal-fired power units.

[0074] In one embodiment, the intermediate stage steam inlet of the rear high-pressure cylinder is connected to the front extraction steam pipe through a third exhaust steam pipe, and a fourth valve is provided on the third exhaust steam pipe to control the opening and closing of the third exhaust steam pipe.

[0075] Specifically, to ensure the stable and safe operation of the high-pressure heating assembly, the amount of steam entering the assembly is limited. Therefore, by connecting the front extraction steam pipe of the front high-pressure cylinder to the intermediate stage steam inlet of the rear high-pressure cylinder, and the rear extraction steam pipe of the rear high-pressure cylinder to the reheat assembly, excess steam that needs to be discharged during the operation of the front high-pressure cylinder can be input into the intermediate stage of the rear high-pressure cylinder. The rear high-pressure cylinder then discharges the excess steam into the reheat assembly according to its own needs. This ensures that the high-pressure heating assembly does not extract too much steam from either the front or rear high-pressure cylinder, thus preventing any impact on its safe operation.

[0076] Since excessive steam discharge typically only occurs during high-load or rated-load operating scenarios, a fourth valve can be installed on the third exhaust pipe to control the opening and closing of the third exhaust pipe. This reduces the probability that, under low-load conditions, the exhaust steam from the front high-pressure cylinder will be input into the intermediate stage of the rear high-pressure cylinder, resulting in a decrease in the steam extraction of the high-pressure heating components and affecting the safe operation of the components.

[0077] In another embodiment, such as Figure 4 As shown, the pre-extraction steam pipe 1018 is connected to the high-pressure exhaust steam transmission pipe 10423 through the third exhaust steam pipe 1019.

[0078] Specifically, the rear high-pressure cylinder 102 and the front high-pressure cylinder 101 are connected to the high-pressure exhaust transmission pipe 10423 of the reheat assembly 1042 via the second exhaust pipe 1027 and the third exhaust pipe 1019, respectively. This allows excess steam that needs to be discharged from the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 during operation to be directly discharged into the reheat assembly 1042. This ensures that the high-pressure heating assembly 105 will not extract too much exhaust steam from the front high-pressure cylinder 101 or the rear high-pressure cylinder 102, thus preventing the safe operation of the high-pressure heating assembly 105 from being affected.

[0079] Similarly, since excessive steam discharge generally only occurs in high-load or rated-load operating scenarios, a fourth valve 10110 can be installed on the third exhaust pipe 1019 to control the opening and closing of the third exhaust pipe 1019. This reduces the probability that under low-load conditions, the exhaust steam in the front high-pressure cylinder 101 will be input into the reheat assembly 1042, resulting in a reduction in the steam extraction of the high-pressure heating assembly 105 and affecting the safe operation of the assembly.

[0080] In one embodiment, the high-pressure heating assembly includes a first high-pressure heater and a second high-pressure heater. The first water outlet of the first high-pressure heater is connected to the boiler through a first water supply pipe, and the first water inlet of the first high-pressure heater is connected to the second water outlet of the second high-pressure heater through a third water supply pipe. The extraction steam temperature of the first high-pressure heater is greater than that of the second high-pressure heater.

[0081] Specifically, a high-pressure cylinder typically has two extraction stages: one with a higher steam temperature and the other with a lower temperature. Therefore, the first high-pressure heater is connected to the first extraction stage of the high-pressure cylinder, extracting higher-temperature steam to heat the feedwater. The second high-pressure heater is connected to the second extraction stage, extracting relatively lower-temperature steam to heat the feedwater. Because the second high-pressure heater extracts lower-temperature steam, after heating the feedwater, it can be fed back into the first high-pressure heater via a third feedwater pipe for reheating, further increasing the feedwater temperature. This reheated feedwater is then transported to the boiler, for example, to the boiler's superheater components to generate main steam.

[0082] In the above embodiments, by setting high-pressure heaters with different extraction steam temperatures, a multi-stage heating system is formed. The steam from the high-pressure cylinder first heats the feedwater through the secondary extraction steam, and then further heats the feedwater through the primary extraction steam. This enables the cascade utilization of thermal energy, reduces energy loss, and improves the cycle thermal efficiency.

[0083] There are several ways to connect the first and second high-pressure heaters to the front and rear high-pressure cylinders. The following are examples of possible connection methods:

[0084] In one embodiment, the front second exhaust port of the front high-pressure cylinder is connected to the first high-pressure heater and the second high-pressure heater via a front extraction steam pipe. The rear first exhaust port of the rear high-pressure cylinder is connected to the first high-pressure heater and the second high-pressure heater via a rear extraction steam pipe.

[0085] Specifically, the front second exhaust port of the front high-pressure cylinder is connected to the first extraction port of the first high-pressure heater and the second extraction port of the second high-pressure heater via a front extraction pipe. Similarly, the rear first exhaust port of the rear high-pressure cylinder is connected to the first extraction port of the first high-pressure heater and the second extraction port of the second high-pressure heater via a rear extraction pipe.

[0086] In another embodiment, the front second exhaust port of the front high-pressure cylinder is connected to the first high-pressure heater through a front extraction steam pipe, and the rear first exhaust port of the rear high-pressure cylinder is connected to the second high-pressure heater through a rear extraction steam pipe.

[0087] Specifically, the front second exhaust port of the front high-pressure cylinder is connected to the first extraction port of the first high-pressure heater via a front extraction steam pipe. The rear first exhaust port of the rear high-pressure cylinder is connected to the second extraction port of the second high-pressure heater via a rear extraction steam pipe.

[0088] In one embodiment, the front second exhaust port of the front high-pressure cylinder is connected to the second high-pressure heater through a front extraction steam pipe, and the rear first exhaust port of the rear high-pressure cylinder is connected to the first high-pressure heater through a rear extraction steam pipe.

[0089] Specifically, the front second exhaust port of the front high-pressure cylinder is connected to the first extraction port of the second high-pressure heater via a front extraction steam pipe. The rear first exhaust port of the rear high-pressure cylinder is connected to the first extraction port of the second high-pressure heater via a rear extraction steam pipe.

[0090] In the above embodiments, the front high-pressure cylinder and the rear high-pressure cylinder can be connected to the first high-pressure heater and the second high-pressure heater through different connection methods, which effectively improves the universality of the thermal system of wide-load high-efficiency coal-fired power units. Users can choose the connection method between the front high-pressure cylinder and the rear high-pressure cylinder and the high-pressure heating component according to the actual construction requirements to construct a high-pressure steam regeneration cycle.

[0091] In one embodiment, such as Figure 5 As shown, a wide-load high-efficiency coal-fired power unit thermal system 500 is proposed. The wide-load high-efficiency coal-fired power unit thermal system 500 includes a front high-pressure cylinder 101, a rear high-pressure cylinder 102, a superheating component 1041 and a reheating component 1042 in the boiler 104, a first high-pressure heater 1053, a second high-pressure heater 1054 and an intermediate-pressure cylinder 106.

[0092] Among them, the steam inlet volume and the flow area of ​​the front high-pressure cylinder 101 are smaller than those of the rear high-pressure cylinder 102. The total steam inlet volume of the front and rear high-pressure cylinders meets the rated operating requirements of the thermal system 500 for wide-load high-efficiency coal-fired power units.

[0093] The front steam inlet 1011 of the front high-pressure cylinder 101 is connected to the main steam transmission pipeline 103 via the first main steam transmission branch 1012, and the rear first steam inlet 1021 of the rear high-pressure cylinder 102 is connected to the main steam transmission pipeline 103 via the second main steam transmission branch 1022. The front first exhaust port 1013 of the front high-pressure cylinder 101 is connected to the rear second steam inlet 1023 of the rear high-pressure cylinder 102 via the first exhaust pipeline 1014.

[0094] A first valve 1015 is installed on the first main steam transmission branch 1012, a second valve 1024 is installed on the second main steam transmission branch 1022, and a third valve 1016 is installed on the first exhaust pipe 1014. The first valve 1015, the second valve 1024, and the third valve 1016 are used to adjust the connection state of the front high-pressure cylinder 101 and the rear high-pressure cylinder 102, including a series connection and a parallel connection.

[0095] The main steam outlet 10411 of the superheating component 1041 in the boiler 104 is connected to the main steam transmission channel 103.

[0096] It is used to generate main steam and input the main steam into the main steam transmission pipeline 103. The water inlet 10412 of the superheating component 1041 is connected to the first water outlet 10531 of the first high-pressure heater 1053 through the first water supply pipeline 1043.

[0097] The steam inlet 10421 of the reheat assembly 1042 is connected to the high-pressure exhaust transmission pipeline 10423, which in turn is connected to the downstream extraction pipeline 1026 via the second exhaust pipeline 1027. The reheat steam outlet 10422 of the reheat assembly 1042 is connected to the reheat steam inlet 1061 of the intermediate-pressure cylinder 106 via the reheat steam delivery pipeline 1044. The reheat assembly 1042 receives a portion of the high-pressure exhaust from the downstream high-pressure cylinder 102, reheats this portion to form reheat steam, and then delivers the reheat steam to the intermediate-pressure cylinder 106 via the reheat steam delivery pipeline 1044 for circulation and work.

[0098] The second exhaust pipe 1027 of the rear high-pressure cylinder 102 is connected to the high-pressure exhaust transmission pipe 10423 of the reheat assembly 1042, and the third exhaust pipe 1019 of the front high-pressure cylinder 101 is connected to the high-pressure exhaust transmission pipe 10423. The high-pressure exhaust transmission pipe 10423 is connected to the steam inlet 10421 of the reheat assembly 1042. A fourth valve 10110 is installed on the third exhaust pipe 1019, and the opening and closing of the third exhaust pipe 1019 is controlled by the fourth valve 10110.

[0099] Boiler feedwater enters the second high-pressure heater 1054 through the second feedwater inlet 10541. The second feedwater outlet 10542 of the second high-pressure heater 1054 is connected to the first feedwater inlet 10532 of the first high-pressure heater 1053 through the third feedwater pipe 10543.

[0100] The front second exhaust port 1017 of the front high-pressure cylinder 101 is connected to the first high-pressure heater 1053 via the front extraction steam pipe 1018, and the rear first exhaust port 1025 of the rear high-pressure cylinder 102 is connected to the second high-pressure heater 1054 via the rear extraction steam pipe 1026. The front second exhaust port 1017 is connected to a section of the extraction steam from the front high-pressure cylinder 101, and the rear first exhaust port 1025 is connected to a section of the extraction steam from the rear high-pressure cylinder 102. The steam temperature extracted from the front high-pressure cylinder 101 is higher than the steam temperature extracted from the rear high-pressure cylinder 102.

[0101] In actual use, the superheating component 1041 in boiler 104 will generate main steam, which will be input into main steam transmission channel 103 through main steam outlet 10411.

[0102] If the first valve 1015 and the second valve 1024 are open and the third valve 1016 is closed, it is determined that the front high-pressure cylinder 101 and the rear high-pressure cylinder 102 are in parallel. The main steam will flow into the front high-pressure cylinder 101 through the first main steam transmission branch 1012 to do work, and at the same time flow into the rear high-pressure cylinder 102 through the second main steam transmission branch 1022 to do work.

[0103] If the first valve 1015 and the third valve 1016 are open, and the second valve 1024 is closed, then the pre-pressure cylinder 101 and the post-pressure cylinder 102 are in series. The main steam will first flow into the pre-pressure cylinder 101 through the first main steam transmission branch 1012 to perform work. A small portion of the exhaust steam from the pre-pressure cylinder 101 enters the first high-pressure heater, while most of the exhaust steam flows into the post-pressure cylinder 102 through the connected first exhaust pipe 1014 to perform work.

[0104] After the rear high-pressure cylinder 102 completes its work, excess exhaust steam can be input into the reheat assembly 1042 via the second exhaust pipe 1027, while the remaining exhaust steam is input into the second high-pressure heater 1054 via the rear first exhaust port 1025 and the rear extraction steam pipe 10526. After the second high-pressure heater 1054 uses the steam extracted from the rear high-pressure cylinder 102 to heat the feedwater, the heated feedwater can be input into the first high-pressure heater 1053 via the second feedwater outlet 10542 and the third feedwater pipe 10513 for reheating.

[0105] When the steam discharged after the pre-pressure cylinder 101 has done its work meets the safe operating conditions of the first high-pressure heater 1053, the fourth valve 10110 is closed, and the third exhaust pipe 1019, which is directly connected to the reheat assembly 1042, is disconnected. At this time, all the exhaust steam from the pre-pressure cylinder 101 will be drawn by the first high-pressure heater 1053 to reheat the feedwater in the first high-pressure heater 1053.

[0106] When the steam to be discharged after the pre-pressure cylinder 101 has done its work does not meet the safe operating conditions of the first high-pressure heater 1053, the fourth valve 10110 is opened to connect the third exhaust pipe 1019, which is directly connected to the reheat assembly 1042. The excess exhaust steam from the pre-pressure cylinder 101 is discharged into the reheat assembly 1042 through the third exhaust pipe 1019. The first high-pressure heater 1053 can then extract the remaining exhaust steam from the pre-pressure cylinder 101 for secondary heating of the feedwater in the first high-pressure heater.

[0107] The first high-pressure heater 1053 feeds heated feedwater through the first feedwater pipe 1043 into the superheating assembly 1041 of the boiler for reheating, thus regenerating main steam. The reheating assembly 1042 receives high-pressure exhaust steam from the rear high-pressure cylinder 102 and / or the front high-pressure cylinder 101 through the high-pressure exhaust steam transmission pipe 10423, and then reheats the high-pressure exhaust steam to generate reheat steam, which is then transmitted to the intermediate-pressure cylinder 106 through the reheat steam transmission pipe 1044 to perform work.

[0108] The wide-load high-efficiency coal-fired power unit thermal system in the above embodiments can significantly increase the main steam pressure entering the high-pressure cylinder under medium and low pressure loads, thereby improving the initial parameters of the thermal cycle, reducing coal consumption, and realizing the wide-load high efficiency of the wide-load high-efficiency coal-fired power unit thermal system.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A thermal system for a wide-load, high-efficiency coal-fired power unit, characterized in that, The thermal system of the wide-load high-efficiency coal-fired power unit includes: a front high-pressure cylinder and a rear high-pressure cylinder; The front steam inlet volume and front flow area of ​​the front high-pressure cylinder are smaller than the rear steam inlet volume and rear flow area of ​​the rear high-pressure cylinder. The total steam inlet volume of the front steam inlet and the rear steam inlet volume meets the rated operating conditions of the thermal system of the wide-load high-efficiency coal-fired power unit. The front steam inlet of the front high-pressure cylinder is connected to the main steam transmission pipeline of the thermal system of the wide-load high-efficiency coal-fired power unit through the first main steam transmission branch; the rear first steam inlet of the rear high-pressure cylinder is connected to the main steam transmission pipeline through the second main steam transmission branch; the front first exhaust port of the front high-pressure cylinder is connected to the rear second steam inlet of the rear high-pressure cylinder through the first exhaust pipe. The first main steam transmission branch is equipped with a first valve, the second main steam transmission branch is equipped with a second valve, and the first exhaust pipe is equipped with a third valve. The first valve, the second valve, and the third valve are used to adjust the connection state of the front high-pressure cylinder and the rear high-pressure cylinder. The connection state includes a series connection state and a parallel connection state.

2. The wide-load high-efficiency coal-fired power unit thermal system according to claim 1, characterized in that, The thermal system of the wide-load high-efficiency coal-fired power unit also includes a boiler and a high-pressure heating component connected to the boiler; The high-pressure heating assembly is used to extract high-pressure exhaust steam from the front high-pressure cylinder and the rear high-pressure cylinder to heat the feedwater entering the boiler. The front second exhaust port of the front high-pressure cylinder is connected to the high-pressure heating component through a front extraction steam pipe. The rear first exhaust port of the rear high-pressure cylinder is connected to the high-pressure heating assembly through a rear extraction steam pipe.

3. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 2, characterized in that, The boiler includes a superheating assembly and a reheating assembly, and the wide-load high-efficiency coal-fired power unit thermal system also includes an intermediate-pressure cylinder; The main steam outlet of the superheating component is connected to the main steam transmission pipeline, and the water inlet is connected to the component outlet of the high-pressure heating component through the first water supply pipeline. The steam inlet of the reheat assembly is connected to the high-pressure exhaust transmission pipeline, and the high-pressure exhaust transmission pipeline is connected to the post-extraction pipeline through the second exhaust pipeline. The reheat steam outlet of the reheat assembly is connected to the reheat steam inlet of the intermediate pressure cylinder via a reheat steam delivery pipeline.

4. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 3, characterized in that, The intermediate stage steam inlet of the rear high-pressure cylinder is connected to the front extraction steam pipe through the third exhaust pipe. A fourth valve is installed on the third exhaust pipe to control the opening and closing of the third exhaust pipe.

5. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 3, characterized in that, The pre-extraction steam pipe is connected to the high-pressure exhaust steam transmission pipe through the third exhaust steam pipe; a fourth valve is installed on the third exhaust steam pipe to control the opening and closing of the third exhaust steam pipe.

6. The wide-load high-efficiency coal-fired power unit thermal system according to any one of claims 2 to 5, characterized in that, The high-pressure heating assembly includes a first high-pressure heater and a second high-pressure heater. The first water outlet of the first high-pressure heater is connected to the boiler through a first water supply pipe, and the first water inlet of the first high-pressure heater is connected to the second water outlet of the second high-pressure heater through a third water supply pipe. The extraction steam temperature of the first high-pressure heater is greater than that of the second high-pressure heater.

7. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 6, characterized in that, The front second exhaust port of the front high-pressure cylinder is connected to the first high-pressure heater and the second high-pressure heater respectively through the front extraction steam pipe; The rear-mounted first exhaust port of the rear-mounted high-pressure cylinder is connected to the first high-pressure heater and the second high-pressure heater respectively through the rear-mounted extraction pipe.

8. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 6, characterized in that, The front second exhaust port of the front high-pressure cylinder is connected to the first high-pressure heater through the front extraction steam pipe. The rear first exhaust port of the rear high-pressure cylinder is connected to the second high-pressure heater through the rear extraction steam pipe.

9. The wide-load high-efficiency coal-fired power unit thermal system according to claim 6, characterized in that, The front second exhaust port of the front high-pressure cylinder is connected to the second high-pressure heater through the front extraction steam pipe; The rear first exhaust port of the rear high-pressure cylinder is connected to the first high-pressure heater through the rear extraction steam pipe.

10. The wide-load, high-efficiency coal-fired power unit thermal system according to claim 1, characterized in that, The first valve is a regulating valve; the second valve and the third valve are shut-off valves.

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