A multi-section maintenance heat recovery system based on heat preservation and pressure preservation for steam heat network

Abstract

The utility model relates to high temperature steam heat network pipeline maintenance reheat operation technical field, and disclose a kind of steam heat network multi-section maintenance reheat system based on heat preservation, the system includes main steam heat source, main pipeline, main pipeline stop valve, branch line pipeline, branch line pipeline stop valve, maintenance area, non-maintenance area, temporary steam heat source etc.The utility model is through partition multi-section maintenance while gradually warming pipe reheat, and for the heat preservation of non-maintenance section area, the mode of pressure conservation, greatly shorten maintenance warm pipe reheat start period.Through temporary steam heat source heat preservation and pressure conservation to non-maintenance area, steam condensation is avoided, while avoiding warm pipe steam waste reduces the heat loss of steam heat network, improves system energy efficiency.The method is simple in operation, economic and convenient, and widely applicable, and can be applied to various high temperature steam heat network maintenance and other steam warming pipe reheat conditions.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature steam heating network pipeline maintenance and repair operation technology, specifically a multi-segment maintenance and repair system for steam heating networks based on heat preservation and pressure maintenance. Background Technology

[0002] Steam heating networks, as a primary heating method, are widely used in residential centralized heating and industrial steam heating. With the continuous expansion and aging of steam heating network systems, the maintenance of steam heating network pipelines has become a crucial aspect of ensuring the stable, efficient, and safe operation of the system. To ensure construction safety, steam shutdown maintenance is an essential operation. However, during steam shutdown maintenance, the steam supply is interrupted for a long time. As the pipelines dissipate heat, the remaining steam inside gradually condenses and cools down. After maintenance, not only is a significant amount of time spent draining the condensate and reheating the pipes, affecting stable and continuous heating, but also a substantial amount of heat is lost, reducing the energy efficiency of the steam heating network.

[0003] Currently, the main method for maintaining steam heating networks relies on the traditional process of sequentially shutting down steam, performing maintenance, warming up the pipes, and then restoring them. However, this method results in long steam supply interruption times, significant condensate heat loss, and low energy efficiency of the steam heating network.

[0004] The patent application, CN202510717235.0, entitled "A Steam Insulation Pipeline for Load Fluctuations Based on Phase Change Thermal Storage and Its Method," proposes to achieve thermal insulation and pressure maintenance of steam heating network pipelines under load fluctuation conditions by laying a phase change material insulation layer on the outside of high-temperature steam pipelines. This reduces heat loss and improves the stability of pipeline operation. However, applying this method to steam heating network pipeline maintenance has several shortcomings. First, for safe construction, the maintenance section of the steam heating network pipeline needs to be cooled to a safe temperature before operation. Laying a phase change material insulation layer on the outside of the pipeline not only hinders heat dissipation in the maintenance section and prolongs the cooling waiting time, but also increases the construction difficulty. In addition, the heat capacity of the phase change material insulation layer is limited, requiring periodic heat storage to function effectively for a long time. However, the steam shutdown time during maintenance is very long, and the phase change material insulation layer cannot guarantee continuous thermal insulation and pressure maintenance for an extended period.

[0005] Therefore, in view of the problems of long interruption time and low steam energy efficiency under the maintenance conditions of steam heating network, the design of a steam heating network maintenance heat repair system and method that can shorten the maintenance interruption time and reduce condensation heat loss by maintaining heat and pressure is of great practical significance. Utility Model Content

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this utility model provides a multi-segment maintenance and reheating system for steam heating networks based on heat preservation and pressure maintenance. It features simple operation, economy and convenience, wide applicability, and can be applied to various high-temperature steam heating network maintenance and other steam shutdown and pipe warming and reheating conditions. It solves the problems of long supply interruption time and low steam energy efficiency during steam heating network maintenance.

[0007] (II) Technical Solution The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A multi-segment maintenance and repair heating system for a steam heating network based on heat preservation and pressure maintenance, including a main steam heat source, a main pipeline, several multi-level branch pipelines, several main pipeline shut-off valves, several branch pipeline shut-off valves, and several temporary steam heat sources; the main pipeline, several main pipeline shut-off valves, several multi-level branch pipelines, and several branch pipeline shut-off valves are respectively connected to form a complete steam heating network; the steam heating network is divided into several maintenance areas and several non-maintenance areas according to maintenance needs, and the several maintenance areas and several non-maintenance areas are... The main pipeline is connected sequentially via a main pipeline shut-off valve or a branch pipeline shut-off valve; the main steam heat source is connected to the upstream end of the main pipeline to continuously supply high-temperature and high-pressure steam; the temporary steam heat source is a movable structure, located at the end of the steam heating network pipeline in the non-maintenance area, to keep the non-maintenance area warm and pressurized; each maintenance area includes one or more independent maintenance sections, each maintenance section including an upstream shut-off valve, a drain valve, a downstream shut-off valve, and a maintenance point, the upstream shut-off valve being arranged close to the main steam heat source, and the drain valve and maintenance point being located between the upstream and downstream shut-off valves.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the main steam heat source is a large-scale heating source with the ability to continuously supply high-temperature and high-pressure steam, including boiler plants, steam heat source plants, or combined heat and power plants; the temporary steam heat source is mobile, including electric heater type, fuel type, or thermal storage type, and the thermal storage type includes solid thermal storage type, phase change thermal storage type, molten salt thermal storage type, or high-temperature and high-pressure steam storage tank type.

[0010] Furthermore, the maintenance section is the pipe section between the upstream and downstream shut-off valves on both sides of the maintenance point, and the pipe section contains at least one steam trap.

[0011] Furthermore, the connection methods between the non-maintenance area and the main pipeline include direct connection and indirect connection; the direct connection is that the non-maintenance area is directly connected to the main pipeline through the main pipeline shut-off valve or the branch pipeline shut-off valve, and the connection path does not pass through any maintenance area; the indirect connection is that the non-maintenance area is indirectly connected to the main pipeline through at least one maintenance area via the branch pipeline shut-off valve.

[0012] The beneficial effects of this utility model are: 1) This multi-segment maintenance and reheating system for steam heating networks based on heat preservation and pressure maintenance significantly shortens the maintenance and reheating start-up period and improves the stability and continuity of the steam heating network by simultaneously warming up and reheating the pipes in multiple sections during maintenance and by using temporary steam heat sources to keep non-maintained areas warm and pressurized.

[0013] 2) This multi-segment maintenance and repair heating system based on heat preservation and pressure maintenance of steam heating network avoids steam condensation by using temporary steam heat sources to keep the non-maintenance areas of the steam heating network warm and pressurized. At the same time, it reduces the heat loss of the steam heating network by avoiding the waste of warming steam during the maintenance process, thereby improving the energy efficiency of the steam heating network system.

[0014] 3) This multi-segment maintenance and reheating system for steam heating networks based on heat preservation and pressure maintenance is simple to operate, economical and convenient; it has wide applicability and can be applied to various high-temperature steam heating network maintenance and other steam shutdown and pipe warming and reheating conditions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the working condition where the non-maintenance area of ​​this utility model is directly connected to the main pipeline; Figure 2 This is a schematic diagram of the non-maintenance area of ​​this utility model being indirectly connected to the main pipeline. Figure 3 This is a schematic diagram of the maintenance section of this utility model.

[0016] In the diagram: 1. Main steam heat source; 2. Main pipeline; 3. Branch pipeline; 4. Main pipeline shut-off valve; 5. Branch pipeline shut-off valve; 6. Temporary steam heat source; 7. Maintenance area; 8. Non-maintenance area; 9. Maintenance section; 91. Upstream shut-off valve; 92. Drain valve; 93. Downstream shut-off valve; 94. Maintenance point. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Example 1, by Figure 1-3This invention presents a multi-segment maintenance and repair system for a steam heating network based on heat preservation and pressure maintenance. The main steam heat source 1 is connected to the upstream end of a main pipeline 2. Several main pipeline shut-off valves 4 are installed at intervals on the main pipeline 2. Several multi-stage branch pipelines 3 are connected to the main pipeline 2 via corresponding branch pipeline shut-off valves 5. The main pipeline 2, main pipeline shut-off valves 4, multi-stage branch pipelines 3, and branch pipeline shut-off valves 5 are assembled to form a complete steam heating network. Based on the actual maintenance location and scope of the steam heating network, the network is divided into several independent maintenance areas 7 and non-maintenance areas 8 by operating the main pipeline shut-off valves 4 and branch pipeline shut-off valves 5. The maintenance areas 7 and non-maintenance areas 8 are connected by corresponding main pipeline shut-off valves 4 or branch pipelines. The shut-off valves 5 are connected sequentially to ensure that each area can be isolated or connected through valve control. The portable temporary steam heat source 6 is placed at the end of the steam heat network pipeline in each non-maintenance area 8 to provide continuous steam to the pipeline network of the non-maintenance area 8 during maintenance to maintain temperature and pressure. One or more maintenance sections 9 are set in each maintenance area 7 according to the distribution of maintenance points 94. An upstream shut-off valve 91 is installed on the side of each maintenance section 9 closer to the main steam heat source 1, and a downstream shut-off valve 93 is installed on the side farther away from the main steam heat source 1. A drain valve 92 is installed on the pipe section between the upstream shut-off valve 91 and the downstream shut-off valve 93, and a specific maintenance point 94 is determined in this pipe section to form a complete maintenance section 9 structure.

[0019] This application achieves flexible division and isolation between maintenance area 7 and non-maintenance area 8 through the main pipeline shut-off valve 4 and branch pipeline shut-off valve 5. The arrangement of the main steam heat source 1 and the mobile temporary steam heat source 6 meets the steam supply needs of different areas. The structured design of maintenance section 9 ensures the independence and safety of maintenance operations, and provides basic structural support for subsequent multi-section maintenance, segmented pipe warm-up and reheating, and heat preservation and pressure maintenance of non-maintenance area 8, ensuring the stability and reliability of system operation.

[0020] In this embodiment, the main steam heat source 1 is a large-scale heating source with the ability to continuously supply high-temperature and high-pressure steam, including boiler plants, steam heat source plants or cogeneration plants; the temporary steam heat source 6 is mobile, including electric heater type, fuel type or heat storage type, and the heat storage type includes solid heat storage type, phase change heat storage type, molten salt heat storage type or high-temperature and high-pressure steam storage tank type.

[0021] In practical applications, a combined heat and power (CHP) plant is typically selected as the main steam heat source 1. It has the ability to continuously and stably supply high-temperature and high-pressure steam, which can meet the steam demand of the entire steam heating network during normal operation and maintenance of the area where heat preservation, pressure maintenance, and pipe warming have been completed. Based on the location distribution of the non-maintenance area 8 and the on-site energy conditions, a mobile molten salt thermal storage temporary steam heat source 6 is selected. This type of temporary steam heat source 6 can be flexibly moved to the end of the pipeline in each non-maintenance area 8. Through the heat storage and heat release characteristics of molten salt, it continuously provides superheated steam to the non-maintenance area 8. If some non-maintenance areas 8 have on-site power supply conditions, an electric heater type temporary steam heat source 6 can also be selected. If there is convenient fuel supply on-site, a fuel type temporary steam heat source 6 can be selected, thereby improving the applicability and flexibility of the system and providing a reliable steam supply guarantee for the heat preservation and pressure maintenance of the non-maintenance area 8.

[0022] Meanwhile, after determining the maintenance point 94 of the steam heating network, an upstream shut-off valve 91 is installed on the side of maintenance point 94 closest to the main steam heat source 1, and a downstream shut-off valve 93 is installed on the side of maintenance point 94 furthest from the main steam heat source 1. The pipe section between the upstream shut-off valve 91 and the downstream shut-off valve 93 is the maintenance section 9. At least one steam trap 92 is installed at a suitable position in this pipe section to ensure that steam and condensate in the pipe can be completely discharged through the steam trap 92 when maintenance is carried out in the maintenance section 9.

[0023] In this embodiment, the connection between the non-maintenance area 8 and the main pipeline 2 includes direct connection and indirect connection. For some non-maintenance areas 8, by opening the corresponding main pipeline shut-off valve 4 or branch pipeline shut-off valve 5, they can be directly connected to the main pipeline 2 without passing through any maintenance area 7 in the connection path, thus forming a direct connection relationship. This type of non-maintenance area 8 can directly obtain steam heat preservation and pressure preservation through the main steam heat source 1 or the terminal temporary steam heat source 6. For some non-maintenance areas 8 on the branch pipeline 3, their connection path to the main pipeline 2 needs to pass through at least one maintenance area 7. The connection with the maintenance area 7 is achieved through the branch pipeline shut-off valve 5, thus indirectly connecting to the main pipeline 2, thus forming an indirect connection relationship. This type of non-maintenance area 8 needs to be kept warm and pressure preserved through the temporary steam heat source 6 when the corresponding maintenance area 7 is under maintenance.

[0024] The document clarifies two connection conditions between the non-maintenance area 8 and the main pipeline 2, providing a basis for the classification design of subsequent maintenance methods. This ensures that the maintenance plan can be accurately adapted to the non-maintenance area 8 with different connection relationships, and that all types of non-maintenance areas 8 can achieve effective heat preservation and pressure maintenance during maintenance, avoiding steam condensation and heat loss.

[0025] Example 2 presents a method for multi-segment maintenance and repair of a steam heating network based on heat preservation and pressure maintenance. The method is divided into two conditions, A and B, according to the connection method between the non-maintenance area 8 and the main pipeline 2. In condition A, the non-maintenance area 8 is directly connected to the main pipeline 2, and in condition B, the non-maintenance area 8 on the branch pipeline 3 is indirectly connected to the main pipeline 2. Operating condition A includes the following steps: S1.1: Temporary steam heat source 6 shall be installed only in the non-maintenance area 8 at the very downstream end of the main pipeline 2; S1.2: In accordance with the order from upstream to downstream of the main steam heat source 1, maintenance work is carried out on each maintenance area 7 one by one; when maintenance is started, the main steam heat source 1 stops supplying steam to the area to be maintained and downstream users, and closes the main pipeline shut-off valve 4 on both sides of the main pipeline 2 of the first maintenance area 7; the main steam heat source 1 supplies superheated steam to the steam heating network upstream of the first maintenance area 7 to maintain the temperature and pressure of the pipeline network in that area; the temporary steam heat source 6 supplies superheated steam to the steam heating network downstream of the first maintenance area 7 to maintain the temperature and pressure of the pipeline network in that area; S1.3: All maintenance sections 9 within the same maintenance area 7 shall be started simultaneously for maintenance: close the upstream shut-off valve 91 and the downstream shut-off valve 93 of maintenance section 9, and open the drain valve 92 to discharge steam and condensate from the pipe; after the pipe temperature of maintenance section 9 drops to the range specified for construction safety, maintenance work shall be carried out; after maintenance is completed, close the drain valve 92 and simultaneously open the upstream shut-off valve 91 and the downstream shut-off valve 93. S1.4: After all maintenance sections 9 in the current maintenance area 7 have been completed, close the main pipeline shut-off valves 4 on both sides of the main pipeline 2 of the next maintenance area; open the main pipeline shut-off valves 4 on both sides of the main pipeline 2 of the current maintenance area 7, and use the main steam heat source 1 to warm up the steam heating network of the current maintenance area 7; at the same time, the main steam heat source 1 continuously supplies superheated steam to the steam heating network at the front end of the next maintenance area to maintain the temperature and pressure of the area; the main steam heat source 1 and the temporary steam heat source 6 dynamically adjust the output flow rate and power according to the maintenance progress and the length of the warming pipeline network; S1.5: Repeat steps S1.3-S1.4 until all maintenance areas 7 are repaired, the main steam heat source 1 resumes normal steam supply to the heating network users, and the temporary steam heat source 6 is shut down and removed.

[0026] Operating condition B includes the following steps: S2.1: Temporary steam heat sources 6 shall be configured in the non-maintenance area 8 at the downstream end of the main pipeline 2 and in the non-maintenance area 8 on each branch pipeline 3. S2.2: Following the order from upstream to downstream of the main steam heat source 1, maintenance work is carried out on each maintenance area 7 one by one. When maintenance is started, the main steam heat source 1 stops supplying steam to the area to be maintained and downstream users; the branch pipe shut-off valves 5 between the non-maintenance area 8 and the adjacent maintenance area 7 on all branch pipes 3 are closed to isolate the non-maintenance area 8 on the branch pipes 3 from the maintenance area 7, so as to avoid the leakage of warm pipe steam to the maintenance area and cause waste; the temporary steam heat source 6 in the non-maintenance area 8 on each branch pipe 3 is opened to keep the steam heating network of the corresponding non-maintenance area 8 warm and pressurized; the main pipe shut-off valves 4 on the main pipes 2 on both sides of the first maintenance area 7 are closed, and the main steam heat source 1 supplies superheated steam to the steam heating network upstream of the first maintenance area 7 to maintain the warm and pressurized area; the temporary steam heat source 6 in the non-maintenance area 8 at the downstream end of the main pipe 2 supplies superheated steam to the steam heating network downstream of the first maintenance area 7 to maintain the warm and pressurized area. S2.3: All maintenance sections 9 within the same maintenance area 7 shall be started simultaneously for maintenance: close the upstream shut-off valve 91 and the downstream shut-off valve 93 of maintenance section 9, and open the drain valve 92 to discharge steam and condensate from the pipe; after the pipe temperature of maintenance section 9 drops to the range specified for construction safety, maintenance work shall be carried out; after maintenance is completed, close the drain valve 92 and simultaneously open the upstream shut-off valve 91 and the downstream shut-off valve 93. S2.4: After all maintenance sections 9 within the current maintenance area 7 are completed, close the main pipeline shut-off valves 4 on both sides of the main pipeline 2 of the next maintenance area; open the main pipeline shut-off valves 4 on both sides of the main pipeline 2 of the current maintenance area 7; if there is a non-maintenance area 8 connected to the main pipeline 2 through the current maintenance area 7, open the branch pipeline shut-off valve 5 between them; use the main steam heat source 1 to warm up the steam heating network of the current maintenance area 7 and the connected non-maintenance area 8; at the same time, the main steam heat source 1 continuously supplies superheated steam to the steam heating network at the upstream end of the next maintenance area to maintain the temperature and pressure of the area; the temporary steam heat source 6 at the downstream end of the main steam heat source 1 and the main pipeline 2 dynamically adjusts the output flow rate and power according to the maintenance progress and the length of the warming pipeline network; after the main steam heat source 1 achieves temperature and pressure preservation for the non-maintenance area 8 on the branch pipeline 3, close the temporary steam heat source 6 in that area; S2.5: Repeat steps S2.3-S2.4 until all maintenance areas 7 are repaired, the main steam heat source 1 resumes normal steam supply to the heating network users, and all temporary steam heat sources 6 are shut down and removed.

[0027] This application designs a maintenance and reheating method based on two operating conditions, A and B, to precisely adapt to the different connection relationships between the non-maintenance area 8 and the main pipeline 2. In operating condition A, the temporary steam heat source 6 is only located in the downstream non-maintenance area 8 of the main pipeline 2. In operating condition B, the temporary steam heat source 6 covers all non-maintenance areas 8 at the downstream end of the main pipeline 2 and on the branch pipeline 3, enabling multi-segment maintenance (maintenance area 7 is maintained one by one, and maintenance section 9 is maintained simultaneously) and segment-by-segment warm-up and reheating. The non-maintenance area 8 is continuously kept warm and pressurized by the temporary steam heat source 6, avoiding steam condensation and heat loss. After maintenance, the main steam heat source 1 is used to quickly warm up and reheat the pipeline, significantly shortening the maintenance interruption time. At the same time, the flexible control of the main pipeline shut-off valve 4 and the branch pipeline shut-off valve 5 ensures operational safety and improves the continuity and energy efficiency of the steam heating network.

[0028] In this embodiment, the main steam heat source 1 remains operational throughout the entire maintenance process. Based on the total length of the steam heating network pipelines that have been repaired, superheated steam is continuously supplied to the corresponding pipeline network. For the pipeline sections that have just been repaired, superheated steam is supplied to achieve warm-up and reheating, so that their temperature and pressure can be quickly restored to normal operating levels. For the pipeline sections that have been warmed up and reheated, an appropriate amount of superheated steam is continuously supplied to maintain the temperature and pressure stability within the pipeline network and to avoid steam condensation and pressure drop due to heat dissipation.

[0029] Before performing maintenance work on each maintenance section 9, close its upstream shut-off valve 91 and downstream shut-off valve 93 and open its drain valve 92. After the temperature inside the pipeline naturally drops to the range specified by the construction safety regulations, the maintenance work can be carried out to ensure the safety of construction personnel and equipment. In working condition A (all non-maintenance areas are directly connected to the main pipeline), only one temporary steam heat source 6 is configured and placed in the non-maintenance area 8 at the downstream end of the main pipeline 2. In working condition B (all non-maintenance areas on the branch pipeline are indirectly connected to the main pipeline), according to the number of non-maintenance areas 8 at the downstream end of the main pipeline 2 and the total number of non-maintenance areas 8 on all branch pipelines 3, a corresponding number of temporary steam heat sources 6 are configured, with one set in each non-maintenance area 8.

[0030] Meanwhile, in operating condition A, a temporary steam heat source 6 with a matching output scale is selected based on the total length of the steam heating network to be maintained, ensuring that it can continuously provide sufficient superheated steam to the pipeline network of the non-maintenance area 8 downstream of the main pipeline 2, maintaining the stability of the pipeline network temperature and pressure; in operating condition B, based on the total number of non-maintenance areas 8 and the specific scale of the steam heating network in each non-maintenance area 8, including pipeline length, volume, etc., a temporary steam heat source 6 with a matching output scale is configured for each non-maintenance area 8, ensuring that the steam supply capacity of a single temporary steam heat source 6 can meet the heat preservation and pressure maintenance requirements of the corresponding non-maintenance area 8.

[0031] In this embodiment, the steam flow rate supplied by the main steam heat source 1 can be estimated based on the actual heat dissipation power per unit length of the steam heating network pipeline, the total length of the pipeline after maintenance, the enthalpy of the supplied steam, the enthalpy of the saturated steam, and an empirical coefficient greater than 1, using the following formula: .

[0032] This application provides a scientific estimation method for the steam supply flow of the main steam heat source 1. By combining actual pipeline parameters (heat dissipation power per unit length, total length of repaired pipelines) and thermal parameters (enthalpy of supplied steam, enthalpy of saturated steam), and introducing empirical coefficient correction, the steam supply flow of the main steam heat source 1 is accurately controlled. This avoids the failure of insulation and pressure maintenance in the non-maintenance area 8 or the repaired pipeline section due to insufficient steam supply, or the waste of steam caused by excessive steam supply, thereby further improving the energy efficiency and economy of the system.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 limitations, 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.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-segment maintenance and repair heating system for a steam heating network based on heat preservation and pressure maintenance, characterized in that: It includes a main steam heat source (1), a main pipeline (2), several multi-level branch pipelines (3), several main pipeline shut-off valves (4), several branch pipeline shut-off valves (5), and several temporary steam heat sources (6). The main pipeline (2), several main pipeline shut-off valves (4), several multi-level branch pipelines (3) and several branch pipeline shut-off valves (5) are connected respectively to form a complete steam heating network. The steam heating network is divided into several maintenance areas (7) and several non-maintenance areas (8) according to maintenance needs. The maintenance areas (7) and the non-maintenance areas (8) are connected in sequence through the main pipeline shut-off valve (4) or the branch pipeline shut-off valve (5). The main steam heat source (1) is connected to the upstream end of the main pipeline (2) and is used to continuously supply high-temperature and high-pressure steam; The temporary steam heat source (6) is a movable structure and is set at the end of the steam heat network pipeline in the non-maintenance area (8) to keep the non-maintenance area (8) warm and pressurized. Each maintenance area (7) includes one or more independent maintenance sections (9), each maintenance section (9) including an upstream shut-off valve (91), a drain valve (92), a downstream shut-off valve (93), and a maintenance point (94). The upstream shut-off valve (91) is located close to the main steam heat source (1), and the drain valve (92) and maintenance point (94) are located between the upstream shut-off valve (91) and the downstream shut-off valve (93).

2. The multi-segment maintenance and repair heating system for a steam heating network based on heat preservation and pressure maintenance according to claim 1, characterized in that: The main steam heat source (1) is a large-scale heating source with the ability to continuously supply high-temperature and high-pressure steam, including boiler plants, steam heat source plants or cogeneration plants; the temporary steam heat source (6) is mobile, including electric heater type, fuel type or heat storage type, the heat storage type includes solid heat storage type, phase change heat storage type, molten salt heat storage type or high-temperature and high-pressure steam storage tank type.

3. The multi-segment maintenance and repair heating system for a steam heating network based on heat preservation and pressure maintenance according to claim 1, characterized in that: The maintenance section (9) is the pipe section between the upstream shut-off valve (91) and the downstream shut-off valve (93) on both sides of the maintenance point (94), and the pipe section contains at least one steam trap (92).

4. A multi-segment maintenance and repair heating system for a steam heating network based on heat preservation and pressure maintenance according to claim 2 or 3, characterized in that: The connection between the non-maintenance area (8) and the main pipeline (2) includes direct connection and indirect connection; The direct connection is that the non-maintenance area (8) is directly connected to the main pipeline (2) through the main pipeline shut-off valve (4) or the branch pipeline shut-off valve (5), and the connection path does not pass through any maintenance area (7). The indirect connection is that the non-maintenance area (8) is indirectly connected to the main pipeline (2) through the branch pipeline shut-off valve (5) via at least one maintenance area (7).

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