Coupling heat supply system

Abstract

The invention belongs to the field of heat supply and discloses a coupling heat supply system which comprises a secondary reheating unit subsystem, a heat supply unit subsystem, a steam coupling pipeline, a water supply coupling pipeline, a high-pressure heat supply integrated pipeline and a low-pressure heat supply integrated pipeline. The secondary reheating unit subsystem comprises an ultrahigh-pressure cylinder, a primary reheating system, a high-pressure cylinder, a secondary reheating system and an intermediate-pressure cylinder which are sequentially connected through pipelines; the heat supply unit subsystem comprises a heat supply steam turbine and a small boiler system for providing a steam source for the heat supply steam turbine; the steam coupling pipeline is connected between an outlet of the primary reheating system and a steam inlet of the heat supply steam turbine, and a temperature and pressure reducing device is arranged on the steam coupling pipeline; the water supply coupling pipeline is configured to enable an outlet of a water supply pump of the heat supply unit subsystem to supply water to a boiler of the secondary reheating unit subsystem; the high-pressure heat supply integrated pipeline gathers exhaust steam from the high-pressure cylinder and extracted steam from the intermediate-pressure cylinder and the heat supply steam turbine; the low-pressure heat supply integrated pipeline collects exhaust steam from the heat supply steam turbine.

Description

Technical Field

[0001] This invention belongs to the field of heating, and particularly relates to a coupled heating system. Background Technology

[0002] When traditional coal-fired power generating units participate in deep grid peak shaving, the power generation load needs to be significantly reduced, resulting in a decrease in the unit's extraction steam parameters (pressure, temperature, and flow rate), making it difficult to meet the stable heating needs of surrounding industrial or residential users. This contradiction severely restricts the flexibility of the unit's peak shaving.

[0003] While some related technologies employ a single unit for heating or set up a simple backup boiler, these systems lack flexibility, have low energy efficiency, and struggle to guarantee heating reliability under conditions of low load or malfunction of the main unit. Summary of the Invention

[0004] In view of this, the present invention discloses a coupled heating system that can overcome the shortcomings of related technologies.

[0005] To achieve the above objectives, the present invention discloses the following technical solution: A coupled heating system, the system comprising: The secondary reheat unit subsystem, the heating unit subsystem, the steam coupling pipeline, the water supply coupling pipeline, the high-pressure heating integrated pipeline, and the low-pressure heating integrated pipeline; The secondary reheat unit subsystem includes an ultra-high pressure cylinder, a primary reheat system, a high pressure cylinder, a secondary reheat system, and an intermediate pressure cylinder, which are connected sequentially by pipelines. The heating unit subsystem includes a heating steam turbine and a small boiler system that provides steam to the heating steam turbine; The steam coupling pipeline is connected between the outlet of the primary reheat system and the steam inlet of the heating turbine, and a de-heating and pressure reducing device is installed on the steam coupling pipeline. The feedwater coupling pipeline is configured to supply water from the outlet of the feedwater pump of the heating unit subsystem to the boiler of the secondary reheat unit subsystem. The high-pressure heating integrated pipeline collects at least the exhaust steam from the high-pressure cylinder, the extraction steam from the intermediate-pressure cylinder, and the extraction steam from the heating turbine; The low-pressure heating integrated pipeline collects at least the exhaust steam from the heating turbine.

[0006] Preferably, the exhaust pipe of the high-pressure cylinder is divided into three paths: the first path is connected to the inlet of the secondary reheat system; the second path is connected to an auxiliary steam header, which is connected to the high-pressure heating integrated pipeline; and the third path is connected to the feedwater pump turbine of the secondary reheat unit subsystem, serving as the driving or backup steam source for the feedwater pump turbine.

[0007] Preferably, the intermediate pressure cylinder is equipped with five stages of steam extraction, and the five stages of steam extraction pipelines are divided into three paths: the first path is connected to the feedwater pump turbine as its main driving steam source; the second path is connected to a heating header, which is connected to the high-pressure heating integrated pipeline; and the third path is connected to the small feedwater pump turbine of the heating unit subsystem as its backup steam source.

[0008] Preferably, the steam extracted from the heating turbine is connected to a heating header via an extraction pipe, and then connected to the high-pressure heating integrated pipeline; the exhaust steam from the heating turbine is connected to a low-pressure heating header via an exhaust pipe, and then connected to the low-pressure heating integrated pipeline.

[0009] Preferably, the exhaust pipe of the heating turbine is also branched to a small feedwater pump turbine, serving as the main driving steam source for the small feedwater pump turbine; the extraction pipe of the heating turbine is also branched to the small feedwater pump turbine, serving as its backup steam source.

[0010] Preferably, it further includes a backup heating subsystem, which includes a high-pressure desuperheating and pressure reducing device and a low-temperature desuperheating and pressure reducing device; the inlet of the high-pressure desuperheating and pressure reducing device is connected to the small boiler system through an auxiliary steam pipe, and its outlet is connected to the high-pressure heating integrated pipeline; the inlet of the low-temperature desuperheating and pressure reducing device is connected to the small boiler system through the auxiliary steam pipe, and its outlet is connected to the low-pressure heating integrated pipeline.

[0011] Preferably, in the water supply coupling pipeline, the outlet pipe of the small water supply pump is also branched to the high-pressure desuperheater and the low-temperature desuperheater to provide cooling water.

[0012] Preferably, the feedwater coupling pipeline specifically includes: the outlet of the small feedwater pump is connected to the small boiler system through a first branch, and connected to the boiler of the secondary reheat unit subsystem through a second branch.

[0013] Preferably, a cooling water branch is provided on the outlet pipe of the feedwater pump of the secondary reheat unit subsystem. This cooling water branch is connected to the heating header or steam pipe in the high-pressure heating integrated pipeline for cooling the heating steam.

[0014] Preferably, the outlet of the small boiler system is connected to the steam inlet of the heating turbine via a steam pipe; the auxiliary steam pipe is also connected to the secondary reheat unit subsystem to provide auxiliary steam for its startup.

[0015] Compared with the prior art, the present invention has the following beneficial effects: On the one hand, through the steam coupling pipeline, when the secondary reheat unit is under low load and the steam supply capacity is insufficient, the heating unit subsystem or direct steam can guarantee the heating supply, enabling the secondary reheat unit to participate in deep peak shaving without being constrained by the heating supply, thereby improving the peak shaving capacity of the heating system. On the other hand, the system provides multiple steam sources (main engine high-pressure exhaust, main engine extraction steam, heating unit extraction and exhaust steam, and small boiler backup steam source) and multiple guarantees (feedwater mutual backup, desuperheater and pressure reducer backup), ensuring uninterrupted heating supply under any single point of failure or specific operating conditions. In addition, this invention realizes the cascade utilization of energy, rationally allocating steam of different qualities, such as high-pressure cylinder exhaust steam and extraction steam at various stages, for power generation, driving feedwater pumps and heating, thereby reducing system energy consumption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a coupled heating system provided in an exemplary embodiment.

[0017] The diagram is marked 1-Ultra-high pressure cylinder; 1-1-First reheat system; 1-2-Steam inlet pipe to high-pressure cylinder; 1-3-Steam to heating unit; 1-4-Desuperheating and pressure reducing device; 2-High pressure cylinder; 2-1-High pressure cylinder exhaust; 2-2-Pipeline to secondary reheat system; 2-3-Secondary reheat system; 2-4-Auxiliary steam header; 2-5-High pressure exhaust to feedwater pump turbine; 2-6-High pressure exhaust to small feedwater pump turbine; 3-Intermediate pressure cylinder; 3-1-Fifth stage extraction steam; 3-2-Fifth stage extraction heating pipe; 3-3-Heating header; 3-4-Fifth stage extraction to small feedwater pump turbine; 4-Feedwater pump turbine; 4-1-Feedwater pump; 4-2-To boiler feedwater; 4-3-Steam cooling feedwater; 4-4-Steam cooling feedwater; 5-High pressure heating pipe 6-Low-pressure heating pipeline; 7-Heating unit; 7-1-Steam pipeline to feedwater pump; 7-2-Steam extraction to heating header; 7-3-Steam extraction to small feedwater pump turbine; 7-4-Exhaust steam; 7-5-Exhaust steam to small feedwater pump turbine; 7-6-Heating header; 7-7-To high-pressure heating pipeline; 7-8-Low-pressure heating header; 8-Heating unit feedwater pump turbine; 8-1-Small feedwater pump; 8-2-Feedwater; 8-3-To small boiler; 8-4-To large boiler; 8-5-Cooling water; 9-Small boiler system; 9-1-Auxiliary steam pipeline; 9-2-Auxiliary steam; 9-3-Steam pipeline to heating unit; 10-High-pressure desuperheater; 10-1-To high-pressure heating pipeline; 11-Low-temperature desuperheater. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of the present invention. Rather, they are merely examples of systems consistent with one or more embodiments of the present invention as detailed in the appended claims.

[0019] It should be noted that the steps of the corresponding methods in other embodiments are not necessarily performed in the order shown and described in this invention. In some other embodiments, the methods may include more or fewer steps than those described in this invention. Furthermore, a single step described in this invention may be broken down into multiple steps in other embodiments; and multiple steps described in this invention may be combined into a single step in other embodiments.

[0020] In coupled heating production lines, high-temperature steam or hot water is often used for sterilization. In related technologies, high-temperature steam and hot water are mostly produced using boiler facilities, and the hot water is typically stored in a hot water tank and supplied as needed. However, this method does not utilize the waste heat generated during sterilization, resulting in a waste of high-temperature hot water and increased production costs.

[0021] To address the shortcomings of related technologies, this invention proposes a coupled heating system.

[0022] Figure 1 This is a schematic diagram of a coupled heating system provided in an exemplary embodiment. (See diagram below.) Figure 1 As shown, the coupled heating system includes: The secondary reheat unit subsystem, the heating unit subsystem, the steam coupling pipeline, the water supply coupling pipeline, the high-pressure heating integrated pipeline, and the low-pressure heating integrated pipeline; The secondary reheat unit subsystem includes an ultra-high pressure cylinder 1, a primary reheat system 1-1, a high pressure cylinder 2, a secondary reheat system 2-3, and an intermediate pressure cylinder 3, which are connected sequentially by pipelines. The heating unit subsystem includes a heating steam turbine 7 and a small boiler system 9 that provides steam to the heating steam turbine 7; The steam coupling pipeline is connected between the outlet of the primary reheat system 1-1 and the steam inlet of the heating turbine 7, and a de-heating and pressure reducing device 1-4 is provided on the steam coupling pipeline. The feedwater coupling pipeline is configured to supply water from the outlet of the feedwater pump 8-1 of the heating unit subsystem to the boiler of the secondary reheat unit subsystem. The high-pressure heating integrated pipeline collects at least the exhaust steam from the high-pressure cylinder 2, the extraction steam from the intermediate-pressure cylinder 3, and the extraction steam from the heating turbine 7; The low-pressure heating integrated pipeline collects at least the exhaust steam from the heating turbine 7.

[0023] In this embodiment, a highly efficient secondary reheat unit, whose peak-shaving capacity is constrained by heating supply, is deeply integrated with a flexible and reliable heating unit through three coupled pipelines: steam, feedwater, and heating. This fundamentally decouples power generation and heating, allowing the main generating units to significantly reduce their power generation load for grid peak shaving without worrying about heating interruptions, thus laying the foundation for achieving deep peak shaving.

[0024] In one embodiment, the exhaust pipe of the high-pressure cylinder 2 is divided into three paths: the first path is connected to the inlet of the secondary reheat system 2-3; the second path is connected to an auxiliary steam header 2-4, which is connected to the high-pressure heating integrated pipeline; and the third path is connected to the feedwater pump turbine 4 of the secondary reheat unit subsystem, serving as the driving or backup steam source for the feedwater pump turbine 4.

[0025] In this embodiment, based on the multi-path distribution of high-pressure cylinder exhaust steam, the high-pressure cylinder exhaust steam is utilized in a refined manner, realizing "one steam for three uses". The first path is used for secondary reheat and subsequent power generation, ensuring the completion of the efficient power generation cycle; the second path leads to the auxiliary steam header for high-pressure heating, directly using high-grade energy for heating, improving energy utilization efficiency; the third path serves as a backup steam source for the feedwater pump turbine, ensuring that the key auxiliary equipment (feedwater pump) still has a high-pressure steam source to drive it when the main unit is under low load and the extraction steam parameters drop, ensuring the safety of boiler water supply, thereby greatly improving the operational reliability of the system under peak-shaving conditions.

[0026] Furthermore, the intermediate pressure cylinder 3 is equipped with five-stage steam extraction 3-1, and the pipeline of the five-stage steam extraction 3-1 is divided into three paths: the first path is connected to the feedwater pump turbine 4 as its main driving steam source; the second path is connected to a heating header 3-3, which is connected to the high-pressure heating integrated pipeline; and the third path is connected to the small feedwater pump turbine 8 of the heating unit subsystem as its backup steam source.

[0027] In this embodiment, based on the multi-path distribution of steam extracted from the intermediate-pressure cylinder, the steam extraction configuration of the intermediate-pressure cylinder is optimized, realizing flexible scheduling and backup of the steam source. The first path serves as the main steam source for the feedwater pump turbine, utilizing extracted steam of moderate grade, which is more economical than directly driving it with fresh steam; the second path provides a stable main heating steam source; the third path provides a backup steam source for the feedwater pump turbine of the heating unit. This creates an important cross-subsystem backup chain: when the heating unit itself lacks steam source, the secondary reheat unit can provide steam source to drive its feedwater pump, ensuring the stable operation of the heating subsystem itself, thereby conversely ensuring the heating reliability of the entire system.

[0028] In one embodiment, the extraction steam from the heating turbine 7 is connected to a heating header 7-6 via an extraction steam pipe 7-2, and then connected to the high-pressure heating integrated pipeline; the exhaust steam from the heating turbine 7 is connected to a low-pressure heating header 7-8 via an exhaust steam pipe 7-4, and then connected to the low-pressure heating integrated pipeline.

[0029] In this embodiment, the energy of the heating unit is utilized in a cascade manner. On the one hand, high-pressure heating is achieved using extracted steam, meeting the needs of high-parameter heat users; on the other hand, low-pressure heating is achieved using the low-pressure exhaust steam after work is completed, improving the overall energy utilization efficiency. Simultaneously, this avoids cold-end losses, reflecting the core energy-saving effect of combined heat and power (CHP).

[0030] In one embodiment, the exhaust pipe 7-4 of the heating turbine 7 is also branched to a small feedwater pump turbine 8, serving as the main driving steam source for the small feedwater pump turbine 8; the extraction pipe 7-2 of the heating turbine 7 is also branched to the small feedwater pump turbine 8, serving as its backup steam source.

[0031] In this embodiment, an independent backup steam source system is constructed within the heating unit. Not only is the exhaust steam used to drive the small feedwater pump turbine, utilizing the lowest grade of energy and improving system economy, but extracted steam is also used as a backup steam source, ensuring reliable operation of the small feedwater pump even when the main steam source (exhaust steam) parameters or flow rate are insufficient (such as during unit startup or low load). This enhances the self-sufficiency and anti-interference capabilities of the heating unit subsystem.

[0032] In one embodiment, a backup heating subsystem is also included, comprising a high-pressure desuperheating and pressure reducing device 10 and a low-temperature desuperheating and pressure reducing device 11; the inlet of the high-pressure desuperheating and pressure reducing device 10 is connected to the small boiler system 9 via an auxiliary steam pipe 9-2, and its outlet is connected to the high-pressure heating integrated pipeline; the inlet of the low-temperature desuperheating and pressure reducing device 11 is connected to the small boiler system 9 via the auxiliary steam pipe 9-2, and its outlet is connected to the low-pressure heating integrated pipeline.

[0033] In this embodiment, a backup heating subsystem is provided to ensure heating supply. When both main and auxiliary steam turbines are unable to provide heating steam due to malfunction or maintenance, a small boiler can be started directly to supply heat to the outside through a desuperheater and pressure reducer. This improves the safety redundancy level and emergency response capability of the entire heating system, enabling the system to continue providing heating even in extreme circumstances.

[0034] Furthermore, in the water supply coupling pipeline, the outlet pipe 8-2 of the small water supply pump 8-1 is also branched to the high-pressure desuperheating and pressure reducing device 10 and the low-temperature desuperheating and pressure reducing device 11 to provide cooling water.

[0035] In this embodiment, by setting up a small feedwater pump to provide cooling water to the desuperheater and pressure reducer, deep coupling and reuse of subsystem functions are achieved. The water output function of the small feedwater pump is extended to provide cooling water to the standby heating subsystem, eliminating the need for a separate cooling water pump for the desuperheater and pressure reducer. This not only simplifies equipment configuration and reduces costs, but also utilizes existing reliable equipment (the small feedwater pump), avoiding the risk of the standby heating system failing due to a dedicated cooling water pump malfunction, further improving the reliability of the standby system.

[0036] In one embodiment, the water supply coupling pipeline specifically includes: the outlet of the small water supply pump 8-1 is connected to the small boiler system 9 through a first branch 8-3, and is connected to the boiler of the secondary reheat unit subsystem through a second branch 8-4.

[0037] In this embodiment, when the main feedwater pump of the secondary reheat unit fails, the specific path for the small feedwater pump to supply water to the large boiler can be activated immediately. The feedwater pump system of the heating unit supplies water to the large boiler, preventing major accidents such as the main unit having to shut down urgently due to water shortage. This plays an important role in ensuring the safety of power grid supply and unit equipment.

[0038] In one embodiment, a cooling water branch 4-3 is provided on the outlet pipe of the feed water pump 4-1 of the secondary reheat unit subsystem. The cooling water branch 4-3 is connected to the heating header 3-3 or the steam pipe in the high-pressure heating integrated pipeline for cooling the heating steam.

[0039] In this embodiment, the cooling water from the main feedwater pump is used to cool the heating steam, achieving internal energy recovery and improving economic efficiency. Using the relatively low-temperature feedwater pump outlet water to cool the heating steam lowers its temperature, making its parameters more suitable for user requirements, and also preheats the boiler feedwater, reducing the fuel consumption required for boiler heating of the feedwater.

[0040] In one embodiment, the outlet of the small boiler system 9 is connected to the steam inlet of the heating turbine 7 via a steam pipe 9-3; the auxiliary steam pipe 9-2 is also connected to the secondary reheat unit subsystem to provide auxiliary steam for its startup.

[0041] In this embodiment, the function of the small boiler system is expanded. Its main function is to drive the heating unit, and its auxiliary function can provide the auxiliary steam required for the start-up of the secondary reheat unit, reduce the dependence on external steam, improve the flexibility and speed of unit start-up, and upgrade it from a single heating unit drive source to the start-up and standby center of the entire system.

[0042] The coupled heating system of the present invention will be described below in conjunction with different operating conditions.

[0043] When the coupled heating system is operating under high load rated conditions, corresponding to peak electricity consumption on the power grid, such as during the peak summer season, the system prioritizes ensuring power supply.

[0044] Under this operating condition, both the secondary reheat unit and the heating unit operate at full load. Steam coupling pipelines 1-3 and 1-4 are closed, and all steam from the outlet of the primary reheat system 1-1 is used to drive the secondary reheat unit itself to maximize power generation. All exhaust steam from the high-pressure cylinder 2-1 enters the secondary reheat system 2-3 to continue generating power. One of the five extraction steam stages 3-1 from the intermediate-pressure cylinder serves as the main steam source for the feedwater pump turbine 4, while the other stage enters the heating header 3-3 via the fifth extraction heating pipeline 3-2, providing steam for the high-pressure heating pipeline 5. The extraction steam from the heating unit 7 enters the heating header 7-6 via pipeline 7-2, also merging into the high-pressure heating pipeline 5; its exhaust steam 7-4 enters the low-pressure heating header 7-8, providing steam for the low-pressure heating pipeline 6. At this time, pipeline 2-5 from the high-pressure cylinder exhaust to the feedwater pump turbine and pipeline 3-4 from the intermediate-pressure cylinder extraction to the small feedwater pump turbine are closed as backup steam sources. Feedwater pumps 4-1 and 8-1 supply water to their respective boilers. The system also utilizes the cooling water branch 4-3 at the outlet of the feedwater pumps to cool the steam in the heating header 3-3, thereby achieving heat recovery.

[0045] Under this operating condition, the system ensures maximum power generation while stably meeting heating demand through multiple steam sources, with each backup path on standby, demonstrating the system's high efficiency and reliability.

[0046] When the coupled heating system is operating under medium load peak shaving conditions, corresponding to the grid load dropping to 30% to 60% of the rated load, the system enters peak shaving mode, which requires reducing power generation while ensuring stable heating.

[0047] At this time, the secondary reheat unit operates at a reduced power generation load. The desuperheating and pressure reducing devices 1-4 on steam coupling pipelines 1-3 and 1-4 are opened for standby. This means that if the small boiler system 9 of the heating unit fails, the high-parameter steam from the secondary reheat unit can immediately drive the heating turbine 7, ensuring uninterrupted heating. Part of the exhaust steam from the high-pressure cylinder 2-1 continues to be used for power generation, while the other part is diverted to the auxiliary steam header 2-4, directly providing steam to the high-pressure heating pipeline 5 to compensate for the reduced extraction steam heating capacity due to the reduced main unit load. The fifth-stage extraction steam from the intermediate-pressure cylinder 3-1 still primarily drives the feedwater pump turbine 4 and provides partial heating, while pipelines 2-5 and 3-4 remain available as critical backup steam sources to stabilize the operation of the feedwater pump turbine when steam source pressure fluctuates. The heating unit 7 adjusts its operating status to prioritize meeting heating demand. The auxiliary steam passage 9-2 of the small boiler system 9 is ready, and its connected high-pressure desuperheating and pressure reducing device 10 and low-temperature desuperheating and pressure reducing device 11 are in hot standby mode. The outlet pipe 8-2 of the small feedwater pump 8-1 is also prepared to provide cooling water to the desuperheater and pressure reducer. This operating condition highlights the importance of the feedwater coupling pipeline, that is, in the event of a failure of the main feedwater pump, emergency water can be supplied to the large boiler through the branch line 8-4 to prevent the accident from escalating.

[0048] Under peak-shaving conditions, the heating capacity can be reliably guaranteed by flexibly switching steam source paths and activating backup systems.

[0049] When the coupled heating system is operating under low-load deep peak-shaving conditions, corresponding to the unit load dropping below 30%, the system faces the challenge of deep peak-shaving.

[0050] Under these extreme conditions, the secondary reheat unit's power generation is extremely low. The role of the steam coupling pipeline becomes crucial. It serves not only as a backup but can also be directly used to drive the heating turbine 7. At this time, the small boiler system 9 can be shut down to reduce plant power consumption, demonstrating the system's operational flexibility and optimization. The diversion strategy of the high-pressure cylinder exhaust 2-1 is further strengthened, with more steam used for direct heating. A key operation is to switch the high-pressure cylinder exhaust pipeline 2-5, which runs from backup to primary use, to drive the feedwater pump turbine 4. This is because, under such low loads, the pressure of the intermediate-pressure cylinder extraction steam 3-1 is insufficient to reliably drive the feedwater pump. The intermediate-pressure cylinder extraction steam is then entirely directed to the heating header 3-3 for heating. The heating unit 7 primarily undertakes the heating task. If the heating demand is also low at this time, the system can choose to drive the heating unit 7 through steam coupling pipelines 1-3 and 1-4, and shut down the entire small boiler system and some related pipelines, using all steam for heating to achieve energy-saving operation.

[0051] Under deep peak shaving conditions, the coupled heating system can still reliably guarantee heating through complex steam source backup and switching logic, thus achieving the core objective.

[0052] When the coupled heating system is in a special operating condition of unit shutdown or maintenance, it has a strong emergency support capability in the event of planned unit maintenance or sudden failure.

[0053] When the secondary reheat unit needs to be shut down for maintenance, the heating unit 7 can continue to operate independently. Its driving steam source is provided by the small boiler system 9. The exhaust steam 7-4 or extraction steam 7-3 of the heating unit 7 itself can be used to drive its small feedwater pump turbine 8. External heating is mainly achieved through auxiliary steam generated by the small boiler system 9, which is cooled and depressurized by the high-pressure desuperheater and pressure reducer 10 and the low-temperature desuperheater and pressure reducer 11 before being sent to the high-pressure and low-pressure heating networks respectively. When the secondary reheat unit needs to be started after maintenance, the small boiler system 9 can also provide the necessary steam for startup through the auxiliary steam pipeline 9-2.

[0054] When heating unit 7 malfunctions or is under maintenance, the secondary reheat unit can continue to operate. At this time, steam can be drawn from the intermediate-pressure cylinder through pipeline 3-4 to the small feedwater pump turbine or other backup steam sources to drive the small feedwater pump 8-1, maintaining the operation of the small boiler system 9. The steam generated by the small boiler system 9 is then directly supplied to the outside through desuperheaters and pressure reducers 10 and 11 to ensure the basic needs of heat users.

[0055] The operation under these special conditions fully verifies the system's extremely high reliability and availability. The failure or maintenance of a single unit will not lead to heating interruptions, and the design of multiple backup paths ensures that the system can perform its core functions under various unforeseen circumstances, demonstrating the advantages of this invention.

[0056] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The foregoing has described specific embodiments of the invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0058] The terminology used in one or more embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in one or more embodiments of the invention and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0059] It should be understood that although the terms first, second, third, etc., may be used to describe various information in one or more embodiments of the present invention, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of one or more embodiments of the present invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0060] The above description is merely a preferred embodiment of one or more embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of the present invention should be included within the protection scope of one or more embodiments of the present invention.

Claims

1. A coupled heating system, characterized in that, The system includes: a secondary reheat unit subsystem, a heating unit subsystem, a steam coupling pipeline, a water supply coupling pipeline, a high-pressure heating integrated pipeline, and a low-pressure heating integrated pipeline; The secondary reheat unit subsystem includes an ultra-high pressure cylinder (1), a primary reheat system (1-1), a high pressure cylinder (2), a secondary reheat system (2-3), and a medium pressure cylinder (3) connected sequentially by pipelines. The heating unit subsystem includes a heating turbine (7) and a small boiler system (9) that provides steam to the heating turbine (7). The steam coupling pipeline is connected between the outlet of the primary reheat system (1-1) and the steam inlet of the heating turbine (7), and a de-heating and pressure reducing device (1-4) is provided on the steam coupling pipeline. The feedwater coupling pipeline is configured to supply water from the outlet of the feedwater pump (8-1) of the heating unit subsystem to the boiler of the secondary reheat unit subsystem. The high-pressure heating integrated pipeline collects at least the exhaust steam from the high-pressure cylinder (2), the extraction steam from the intermediate-pressure cylinder (3), and the extraction steam from the heating turbine (7); The low-pressure heating integrated pipeline collects at least the exhaust steam from the heating turbine (7).

2. The system according to claim 1, characterized in that, The exhaust pipe of the high-pressure cylinder (2) is divided into three lines: The first path is connected to the inlet of the secondary reheat system (2-3); The second route is connected to an auxiliary steam header (2-4), which is connected to the high-pressure heating integrated pipeline. The third path is connected to the feedwater pump turbine (4) of the secondary reheat unit subsystem, serving as the driving or backup steam source for the feedwater pump turbine (4).

3. The system according to claim 2, characterized in that, The intermediate pressure cylinder (3) is equipped with a five-stage steam extraction system (3-1), and the pipelines of the five-stage steam extraction system (3-1) are divided into three paths: The first path is connected to the feedwater pump turbine (4) as its main driving steam source; The second line is connected to a heating manifold (3-3), which is connected to the high-pressure heating integrated pipeline; The third path is connected to the small feedwater pump turbine (8) of the heating unit subsystem as its backup steam source.

4. The system according to claim 1, characterized in that, The extraction steam of the heating turbine (7) is connected to a heating header (7-6) through an extraction steam pipe (7-2), and then connected to the high-pressure heating integrated pipeline; the exhaust steam of the heating turbine (7) is connected to a low-pressure heating header (7-8) through an exhaust steam pipe (7-4), and then connected to the low-pressure heating integrated pipeline.

5. The system according to claim 4, characterized in that, The exhaust pipe (7-4) of the heating turbine (7) is also branched to a small feedwater pump turbine (8) as the main driving steam source of the small feedwater pump turbine (8); the extraction pipe (7-2) of the heating turbine (7) is also branched to the small feedwater pump turbine (8) as its backup steam source.

6. The system according to claim 1, characterized in that, It also includes a backup heating subsystem, which includes a high-pressure desuperheating and pressure reducing device (10) and a low-temperature desuperheating and pressure reducing device (11). The inlet of the high-pressure desuperheating and pressure reducing device (10) is connected to the small boiler system (9) through an auxiliary steam pipe (9-2), and its outlet is connected to the high-pressure heating integrated pipeline. The inlet of the low-temperature desuperheating and pressure reducing device (11) is connected to the small boiler system (9) through the auxiliary steam pipe (9-2), and its outlet is connected to the low-pressure heating integrated pipeline.

7. The system according to claim 6, characterized in that, In the water supply coupling pipeline, the outlet pipe (8-2) of the small water supply pump (8-1) is also branched to the high-pressure desuperheating and pressure reducing device (10) and the low-temperature desuperheating and pressure reducing device (11) for providing cooling water.

8. The system according to claim 1, characterized in that, The water supply coupling pipeline specifically includes: the outlet of the small water supply pump (8-1) is connected to the small boiler system (9) through the first branch (8-3), and is connected to the boiler of the secondary reheat unit subsystem through the second branch (8-4).

9. The system according to claim 1, characterized in that, A cooling water branch (4-3) is provided on the outlet pipe of the feed water pump (4-1) of the secondary reheat unit subsystem. The cooling water branch (4-3) is connected to the heating header (3-3) or steam pipe in the high-pressure heating integrated pipeline for cooling the heating steam.

10. The system according to claim 1, characterized in that, The outlet of the small boiler system (9) is connected to the steam inlet of the heating turbine (7) via a steam pipe (9-3); the auxiliary steam pipe (9-2) is also connected to the secondary reheat unit subsystem to provide auxiliary steam for its startup.

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