Method and system for increasing heat supply flow of cogeneration unit

Abstract

The invention discloses a method and system for increasing the heat supply flow of a cogeneration unit, and belongs to the technical field of heat supply system optimization of the cogeneration unit. According to the method, the steam loss is reduced by checking the state of a system valve and treating steam-water leakage; the steam source pressure is dynamically increased according to requirements, and the valve adjusting margin is recovered; meanwhile, a standby temperature reduction station is put into use to increase the flow area and reduce the system resistance; and the same-parameter steam sources of adjacent machines can be arranged in parallel so as to compensate insufficient heat supply of a single machine and prevent steam channeling. The heat supply flow of the unit can be effectively increased, and safe and stable operation of the system is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of heating system optimization technology for cogeneration units, and in particular to a method and system for increasing the heat supply flow of cogeneration units. Background Technology

[0002] With the continuous development of power plant heating services and the increasing demands of heat users, the contradiction between limited heating supply and unmet demand is becoming increasingly prominent. Restricted heating supply will severely impact some heat users and also cause economic losses to power plants. Meanwhile, for older units facing shutdown, or units whose heating demand only slightly exceeds supply capacity during certain periods, redesigning, upgrading, or significantly optimizing the heating system is often not cost-effective and has poor economic returns; moreover, optimization work must be completed while the units are out of service, resulting in long implementation cycles and limited timeliness. Therefore, transitioning from temporary measures to long-term upgrades is crucial for ensuring heating supply.

[0003] Currently, some combined heat and power (CHP) units employ extraction steam heating schemes, using extracted steam from cold / hot reheat units or intermediate turbine stages as the heating steam source. This approach features low cold source loss, high energy utilization, and flexible control. When the unit load decreases significantly, the extraction steam pressure becomes too low. In this case, the heating steam source can be switched from extraction steam to superheater steam supplied by the superheater outlet pipes to meet the heating pressure requirements. However, the newly added superheater steam source is often a later modification, lacking integrated design with the original heating system's pipes and valves, causing deviations from the system's rated parameters. Furthermore, with the development of power plants and the gradual increase in heat users, the demand for heating is further increasing, and the existing heating system can no longer provide sufficient flow. To address the aforementioned problem of insufficient heating flow, power plants generally adopt heating system optimization and upgrade solutions such as replacing the extraction steam source, adding backup steam sources, and optimizing the pipe and valve structure.

[0004] Existing solutions involve high investment costs and require maintenance during unit shutdowns, making them unreliable in terms of timeliness. Furthermore, they are not cost-effective if the heating flow is only temporarily or slightly insufficient. Therefore, there is a lack of systematic methods to increase heating flow even during normal unit operation, or to improve heating flow through low-cost, short-term localized optimization. Summary of the Invention

[0005] The main objective of this invention is to provide a method for increasing the heat supply flow of a combined heat and power (CHP) unit. The aim is to overcome the core defects of existing technologies, such as limited heating capacity, low system operating efficiency, and high safety risks, through systematic operational optimization and adjustment, so as to effectively increase the heat supply flow and reliably ensure the safe and stable operation of the system.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for increasing the heat supply flow of a cogeneration unit, comprising: S1, checking and adjusting the opening status of all shut-off valves and regulating valves in the heating pipeline, checking for pipeline leaks, checking the opening degree and internal leakage of the drain valves, adjusting them to allow only a small amount of steam to be discharged, confirming that the drain valves are working properly and performing maintenance, so as to reduce system steam and water loss. S2 increases the pressure of the heating steam source. For superheated steam sources, this is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load. S3, put the standby heating desuperheating station into operation, and perform the connection, pipe warming, drainage and commissioning operations in sequence to reduce the system flow resistance by increasing the flow area of ​​the desuperheating station; S4, the same type of heating steam source pipelines of adjacent units are operated in parallel, and the warm-up, drainage and commissioning are completed in sequence. The system resistance is further reduced by increasing the flow area of ​​the steam source side pipeline. S5. Conduct resistance analysis on the pipe and valve structure of the heating system, locate high-resistance parts, and replace pipes or valves with smaller diameters or optimize the pipe layout through design calculations or test verification to increase the heating flow rate. S6, during unit shutdown, adds a new heating pipeline from the same source as the existing heating steam source and operates in parallel with the original pipeline to increase the steam source delivery capacity.

[0007] In one embodiment of the present invention, S1 includes: Input valve control commands and field feedback signals, compare the set opening degree of the shut-off valve and the actual position of the regulating valve; if there is a deviation, output an alarm and trigger a maintenance work order to ensure that all main valves are opened to the correct position; Input pipeline pressure, flow rate, and inspection images to identify whether there are leaks in the heating pipeline; if abnormal pressure drop or steam leakage is detected, output leak location information and generate pipeline switching and isolation repair instructions; Input the steam trap opening, steam discharge, and steam trap operating status data to determine if there is over-opening or internal leakage; if a large amount of steam is found to be discharged, output an adjustment command to control the steam discharge to a trace amount of steam, and initiate a bypass throttling and isolation troubleshooting process for the faulty steam trap.

[0008] In one embodiment of the present invention, S2 includes: Real-time monitoring of heating flow and main steam pressure. When the heating flow is at a high level and the main steam pressure is low, it is determined that the heating system's adjustment capacity is limited. At this time, the pressure regulating valves of the heating steam source and the desuperheating station tend to be fully open, and the system issues an early warning signal that the heating pressure is difficult to maintain. Based on the early warning information, a control command to increase the main steam pressure is generated. By adjusting the boiler operating parameters, the main steam pressure is appropriately increased to restore the control margin of each regulating valve on the heating side, thereby increasing the pressure of the heating main pipe and ensuring a stable supply of heat flow. Continuously monitor the response status of heating pressure and flow. Once the system is confirmed to have returned to normal, output a regulation completion signal and simultaneously assess whether the main steam pressure is close to the upper limit of safe and economical operation of the unit. If it is close, stop further pressure increase to ensure that the unit's operational safety is not sacrificed while guaranteeing heating capacity.

[0009] In one embodiment of the present invention, S3 includes: Real-time collection of heating main pipe pressure data. When the heating pressure is detected to drop abnormally to below the critical value, and the user-side valves continue to open and the flow demand remains high, making it difficult for the pressure to rise, it is determined that the main desuperheating station has insufficient flow capacity and outputs a system blockage warning. Start the standby heating desuperheating station, and sequentially perform the connection, pipe warming, drainage and commissioning operations. Collect the valve opening and pressure response data of the standby desuperheating station. After it is opened to the fixed adjustment opening, the system recognizes that the flow area has increased, the flow resistance has decreased, and the pressure of the heating main pipe begins to rise. The system continuously monitors the recovery trend of heating pressure. When the pressure rises back to the normal operating range and the valves on the user side gradually close due to the satisfaction of demand, it collects data on the opening changes of the regulating valves on the heating steam source side and the desuperheating station to confirm the recovery of its control margin. The system outputs a pressure stabilization signal to complete dynamic adjustment.

[0010] In one embodiment of the present invention, S4 includes: Monitor the current heating demand and supply status of the unit. When it is detected that the heating flow of a single unit is insufficient and the regulating valve is close to being fully open, it is determined that the heating capacity of the unit has reached the upper limit and outputs a signal to start the support of the adjacent unit. Call the backup channel of the adjacent unit of the same type to the heating pipeline, perform pipe warming, drainage and commissioning operations, collect pipeline temperature and pressure data to confirm that the parallel connection conditions are met, open the heating steam source pressure regulating valve to a fixed opening, the system recognizes the increase in total heating flow area and realizes flow compensation. Continuously collect steam pressure, flow rate, and valve status data on both sides of the system. Utilize the natural flow resistance formed by the pipeline check valve and the long-distance arrangement of small-diameter pipes to prevent steam backflow, ensuring the independent and stable operation of the two thermal systems. The system outputs a status confirmation signal indicating improved heating capacity and no risk of crossflow.

[0011] In one embodiment of the present invention, S5 includes: Collect geometric parameters and operating condition data of each pipe section and valve in the heating system, construct a pipe and valve structural resistance model, input pipe and valve design parameters, output the friction and local resistance distribution of each node, and identify high-resistance sections. Based on the model analysis of the flow capacity of key nodes of pipe valves, the actual flow rate is compared with the design flow rate. When the actual heating flow rate is detected to be significantly lower than the target value and the regulating valve tends to be fully open, the resistance extreme point is located, and a certain key pipe valve component is identified as the source of the system's maximum resistance. Based on the historical use of the pipeline and its current operating conditions, determine the original design application scenario of the valve and output a diagnostic conclusion.

[0012] In one embodiment of the present invention, S6 includes: Collect boiler soot blowing system operating parameters, identify the pressure and flow status of soot blowing steam source, confirm that it is the same source as the shielded heating steam source during deep peak shaving, and that the soot blowing pressure is stable and the flow is sufficient during normal operation, and that it has the potential to be used as a backup heating steam source. Based on the shared steam source characteristics, a connection channel model from the soot blowing steam source to the heating pipeline is constructed. The pipeline connection location, valve configuration and control logic are input. The simulation and verification are performed to show that during non-working periods or low demand periods of soot blowing, the soot blowing steam can be directionally delivered to the heating system to realize the parallel expansion of the steam source. After the system performs steam source switching or parallel steam supply operation, it monitors the pressure and flow changes of the heating main pipe in real time. When it detects that the heating capacity has increased and the system pressure tends to stabilize, it outputs a confirmation signal that the soot blowing steam source has been successfully replenished, thus completing the dynamic enhancement of the heating flow.

[0013] In one embodiment of the present invention, the method further includes: Collect historical annual heating load data, analyze the trend of user demand changes, and when it is detected that the heating demand continues to grow and the existing system is approaching or reaching its flow limit under peak conditions, output an early warning signal that the system supply capacity will be insufficient. Based on future load forecasts and existing system bottleneck analysis, a model of the overall upgrade scheme for the heating system is constructed. Modification parameters such as expanding the diameter of the heat reheat valve and throttling the medium-pressure regulating valve are input, and technical, economic and feasibility simulations are conducted to verify the technical, economic and feasibility, and a system-level capacity expansion optimization strategy is generated. After confirming the feasibility of the upgrade plan, a system reconfiguration command is output, and engineering modifications such as expanding the diameter and increasing the capacity of the heat recovery pipeline valves and adjusting the operation mode of the medium-pressure regulating valve are initiated. After the implementation is completed, the effect of improving the heating capacity of the entire system is monitored, and a final status confirmation signal is output.

[0014] To achieve the above objectives, a second aspect of the present invention provides a system for increasing the heat supply flow of a cogeneration unit, comprising: a valve status inspection and steam-water loss control module, used to check and adjust the opening status of all shut-off valves and regulating valves in the heating pipeline, investigate pipeline leaks, check the opening degree and internal leakage of the drain valves, adjust to allow only a small amount of steam to be discharged, confirm that the drain is working properly and perform maintenance, so as to reduce the system steam-water loss; The steam source pressure boosting module is used to increase the pressure of the heating steam source. For superheated steam sources, it is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load. The backup desuperheating station activation module is used to activate the backup heating desuperheating station. It sequentially performs connection, pipe warming, drainage and activation operations, and reduces system flow resistance by increasing the flow area of ​​the desuperheating station. The adjacent unit steam source parallel operation module is used to operate the same type of heating steam source pipeline of the adjacent unit in parallel, and complete the warm-up, drainage and commissioning in sequence. The system resistance is further reduced by increasing the flow area of ​​the steam source side pipeline. The pipe and valve resistance analysis and structure optimization module is used to perform resistance analysis on the pipe and valve structure of the heating system, locate high resistance parts, and replace pipes or valves with smaller diameters or optimize the pipe layout through design calculations or test verification to increase the heating flow rate. The homogeneous heating pipeline capacity expansion module is used to add a new homogeneous heating pipeline to the existing heating steam source during unit shutdown, and to operate in parallel with the original pipeline to increase the steam source delivery capacity.

[0015] The methods and systems of this invention are more systematic, innovative, timely, and economical than traditional methods. They encompass everything from temporary measures to address immediate needs to long-term upgrades that provide a permanent solution, thereby improving the reliability of heat supply. Furthermore, this method can increase heat flow at zero or lower cost by changing the operating mode or selectively optimizing the pipe and valve structure on a small scale, without altering the existing heating system. This reduces power plant investment while ensuring heat supply, thus possessing significant potential for widespread application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A flowchart of a method for increasing the heat supply flow rate of a combined heat and power unit is provided as an embodiment of the present invention; Figure 2 This is a schematic diagram of the heating system provided in an embodiment of the present invention; Figure 3This is a schematic diagram of a device for increasing the heat supply flow of a combined heat and power unit, provided in an embodiment of the present invention. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0019] The following describes, with reference to the accompanying drawings, a method and system for increasing the heat supply flow of a combined heat and power unit according to an embodiment of the present invention.

[0020] This embodiment provides a method for increasing the heat supply flow of a combined heat and power (CHP) unit. Taking Units 3 and 4 of a power plant as an example, currently both Units 3 and 4 supply heat to the outside world by extracting reheat steam and desuperheating and depressurizing it. The pressure before the desuperheater and pressure reducer is 1.85–3.67 MPa, and the temperature is 538°C; the working pressure after the desuperheater and pressure reducer is 1.25 or 1.35 MPa (depending on the user's operating status), and the temperature is 280°C.

[0021] To ensure the safety of heating steam supply during the deep peak shaving period of the units, in 2021, during the maintenance of Units #3 and #4, the original steam supply pipeline from the auxiliary steam pipe to the heating pipe was modified to allow heating from the auxiliary steam pipe. When the deep peak shaving of the units cannot meet the heating pressure, the heating steam source can be switched from the auxiliary steam pipe to the auxiliary steam pipe. The heating pressure from the auxiliary steam pipe is 15.5–17 bar, the temperature is 330–360°C, and the safety valve operating pressure of the auxiliary steam pipe is 19.8 bar. This can meet the heating needs of users during the deep peak shaving period of the units. This heating system is as follows: Figure 2 As shown.

[0022] In 2024, heating flow rates increased year-on-year in all months compared to 2023, indicating increased heating demand. Due to seasonal factors, the peak heating demand period is from October to March of the following year. The highest heating flow rate occurs annually in December, reaching 27.6 t / h in 2023 and 30.2 t / h in 2024. Currently, under deep-heating conditions, excessive user demand (>28 t / h) can lead to situations where, even with the steam source activated and regulating valves fully open, heating pressure cannot be maintained and heating flow rate cannot be increased. Figure 1 As shown, the method includes the following steps: S1. Check and adjust the opening status of all shut-off valves and regulating valves in the heating pipeline, check for pipeline leaks, check the opening degree and internal leakage of the drain valves, adjust them until only a small amount of steam is discharged, confirm that the drain is working properly and perform maintenance to reduce system steam and water loss.

[0023] Specifically, check the valve status and reduce steam and water loss. On-site check that the relevant shut-off valves in the heating pipeline are fully open, or if not, fully open; check that the regulating valves are in their actual open positions, or contact maintenance for repair; check that there are no leaks in the heating system pipelines, or if so, switch the pipeline operation in time and isolate and repair the leak; check whether the drain valves along the route are opened too wide, check whether there is internal leakage when the valves are closed, and adjust the drains to allow at least a certain amount of steam to be discharged; confirm that all steam traps are working properly and that there is no large amount of steam leakage, or if so, bypass the drains and isolate and repair the steam traps.

[0024] For example, valve opening / closing status checks and actuator calibration are performed. Before and during the operation of the heating system, all shut-off valves and regulating valves in the pipeline must be checked one by one to ensure they are in the correct opening / closing state. Check on-site whether each shut-off valve is fully open. If it is found to be partially open, it should be manually or adjusted to the fully open position via the actuator to avoid additional pressure drop due to throttling. For regulating valves, verify that the valve position feedback displayed on the DCS system matches the actual opening on-site. If there is a discrepancy or jamming, contact maintenance personnel immediately to ensure the valve can accurately respond to control commands. Simultaneously, check whether the air supply, power supply, and control signals of the valve actuator are normal to ensure its controllability and reliability, providing a foundation for stable heating in the future.

[0025] Furthermore, system sealing checks and leak mitigation are crucial. A comprehensive inspection of the heating pipeline system is conducted, focusing on leak-prone areas such as welds, flange connections, valve packing, and expansion joints. Visual inspection, infrared thermography, or acoustic detection are used to determine if steam leaks are present. Once a leak is detected, its impact and safety risks should be immediately assessed. For isolated pipe sections, switching to an alternate path is necessary, and the affected section should be depressurized, isolated, and repaired. For sections that cannot be immediately shut down, temporary sealing or diversion measures should be implemented to prevent further steam and water loss. By establishing a leak log and implementing closed-loop management, the system's sealing performance is ensured, minimizing energy waste and operational safety hazards.

[0026] Furthermore, optimize and maintain the condensate drainage system. Thoroughly inspect all condensate drain valves along the heating system to ensure their opening is appropriate and to prevent excessive steam leakage. For closed drain valves, check for internal leaks and install blind flanges or replace valves if necessary. Adjust the discharge rate at each drain point to ensure only a small amount of steam escapes, guaranteeing timely condensate removal while minimizing effective heat loss. Simultaneously, confirm that all steam traps (such as inverted bucket type and thermodynamic type) are functioning correctly, without blockages, malfunctions, or steam resistance. If a steam leak is detected due to a condensate trap malfunction, immediately switch to bypass control, isolate the faulty trap, and arrange for repair or replacement to ensure efficient operation of the condensate drainage system and guarantee overall heating efficiency.

[0027] S2 increases the pressure of the heating steam source. For superheated steam sources, this is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load.

[0028] Understandably, for superheater steam sources, increasing the main steam pressure is necessary; for cold / hot reheat or intermediate stage steam extraction sources from the turbine, increasing the unit load is necessary.

[0029] In one embodiment of the invention, the plant uses bypass steam as the heating steam source for deep peak shaving, and the main steam pressure directly affects the heating pressure and flow rate. In actual operation, when the heating flow rate is around 28 t / h and the main steam pressure is <110 bar, both the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve will be fully open, making it difficult to maintain the heating pressure and limiting the heating flow rate. At this time, if the operators appropriately increase the main steam pressure to 112 bar, the margin of the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve will recover, the heating pressure will return to normal, and the heating flow rate will be sufficient. However, for the sake of unit safety and economy, the main steam pressure cannot be increased indiscriminately, so the degree of increase in heating flow rate is limited.

[0030] Specifically, under the deep peak-shaving operation conditions of the thermal power plant, in order to balance the stability of the unit at low loads and the demand for external heating, the plant uses steam from a screen-type superheater (screen-type superheater) as the main heating steam source. Since the screen-type superheater steam source is directly taken from the main steam system, its pressure level is closely related to the main steam pressure. Therefore, the level of the main steam pressure directly determines the driving capability of the heating steam source, and thus has a decisive impact on the pressure stability and transportable flow rate of the heating header. In this operating mode, the pressure regulation of the heating system relies on the coordinated control of the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve; the regulation margin of both is crucial to maintaining stable heating.

[0031] In actual operation, when the heating demand reaches approximately 28 t / h, if the main steam pressure is below 110 bar, the heating system's regulation capacity faces a severe challenge. At this point, both the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve tend to be fully open (close to 100%), losing any margin for further regulation. This results in the system being unable to effectively compensate for pipeline pressure drop and user-side pressure fluctuations, causing the heating pressure to continuously decline and become difficult to maintain within the set range. Ultimately, this limits the heating flow rate, failing to meet the high-load demands of users. To address this issue, operators implemented a control measure to increase the main steam pressure, moderately raising it to 112 bar. This significantly enhanced the pressure margin on the steam source side, causing the opening of the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve to return to a controllable range, regaining regulation capacity. The heating main pipe pressure subsequently returned to normal levels, allowing for a stable heating flow rate, and the system returned to a safe operating state.

[0032] However, the increase in main steam pressure is not unlimited. Excessively high main steam pressure increases thermal stress on the boiler's heating surfaces, affecting hydrodynamic stability and potentially triggering safety valves, threatening the safety of the unit. Furthermore, increasing main steam pressure usually requires increased fuel input or adjustments to combustion air distribution, which may reduce the unit's operational economy under low load conditions. Therefore, considering both unit safety and economy, the extent of main steam pressure increases is strictly limited, allowing only short-term adjustments within a small range. This also means that increasing heat flow by raising main steam pressure has significant limitations; it is only suitable for short-term emergencies or small-scale increases in supply, and cannot fundamentally solve the problem of insufficient heating capacity, making it difficult to cope with future continuously growing heating demand.

[0033] S3, put the standby heating desuperheating station into operation, and perform the connection, pipe warming, drainage and commissioning operations in sequence to reduce the system flow resistance by increasing the flow area of ​​the desuperheating station.

[0034] It is understandable that the backup heating desuperheating station is connected, warmed up, drained, and put into operation in sequence, thereby reducing system resistance by increasing the circulation area of ​​the heating desuperheating station.

[0035] In one embodiment of the invention, the plant failed to adequately control the heating switching process during a deep peak shaving operation, causing the heating pressure to drop to a minimum of 1.27 MPa. At this point, the heating pressure failed to meet user demand, leading to the continuous widening of user-side valves. Under high flow demands exceeding 28 t / h, the heating pressure struggled to return to normal or even maintain its current level. Operators sequentially connected, warmed, drained, and put into operation the backup heating desuperheating station pipeline. After the backup desuperheating station pressure regulating valve was opened to a fixed degree, the flow area of ​​the heating desuperheating station increased, resistance decreased, and the heating pressure rose back to 1.35 MPa. Subsequently, as user demand was met and user-side valves were closed, the margins of the heating steam source pressure regulating valve and the desuperheating station pressure regulating valve recovered.

[0036] Specifically, during a deep peak-shaving operation, the plant's heating system switching operation was improperly controlled, failing to adequately preheat and drain backup pipelines. This resulted in significant pressure fluctuations in the system when the main heating desuperheating station switched over or when the load suddenly increased. The pressure in the heating main pipe dropped rapidly, reaching a low of 1.27 MPa, far below the normal operating pressure range. This pressure level could not meet the minimum drive requirements of the user-side heating system, causing the user-side automatic regulating valves to continuously open to maintain flow, further exacerbating the pressure drop in the pipeline network and creating a vicious cycle of "low pressure → valve opening → increased flow demand → even lower pressure." Under this condition, even with the main steam source pressure and regulating valves nearly fully open, the system still struggled to restore the heating pressure to normal values. The high-flow (above 28 t / h) heating state was on the verge of collapse, the heating quality was severely degraded, and there was a risk of affecting user production and heating safety.

[0037] To quickly restore system stability, operators immediately activated the emergency response procedure and put the backup heating desuperheating station into operation. Following standard operating procedures, the backup desuperheating station pipeline was sequentially connected, warmed up, drained, and put into operation to ensure adequate preheating and removal of accumulated water, preventing water hammer and thermal stress damage. After confirming the pipeline's safety, the pressure regulating valve of the backup desuperheating station was gradually opened to a fixed position. With this connection operational, the total flow area of ​​the system significantly increased, alleviating the bottleneck effect of the original main desuperheating station operating alone, reducing overall flow resistance, and allowing the pressure in the main heating pipe to gradually recover. Approximately 15 minutes after the backup desuperheating station was activated, the heating pressure successfully recovered to 1.35 MPa, returning to a safe and controllable range, the heating flow rate stabilized, and the system was out of danger.

[0038] As heating pressure recovered, user-side heat demand was effectively met, and user-side regulating valves automatically closed due to sufficient pressure, returning flow to normal levels. Simultaneously, the openings of the pressure regulating valves on the steam source side and the desuperheating station also decreased, regaining sufficient regulatory margin, and the system's control capability was fully restored. This incident not only verified the effectiveness of the backup desuperheating station as an emergency capacity expansion measure but also exposed the high sensitivity of the heating system to operational precision under deep peak-shaving conditions. The plant subsequently reviewed the process, optimized the switching operation procedures, and strengthened operator training to ensure a smooth and orderly heating switchover under similar conditions, avoiding significant pressure fluctuations and improving the system's reliability and resilience.

[0039] S4 operates in parallel with the same type of heating steam source pipelines of adjacent units, completing the warm-up, drainage and commissioning in sequence, and further reducing system resistance by increasing the flow area of ​​the steam source side pipeline.

[0040] It is understandable that the pipelines of the same type of heating steam source in adjacent units are warmed up, drained, and put into use in sequence, thereby reducing system resistance by increasing the flow area of ​​the steam source pipelines.

[0041] In one embodiment of the invention, adjacent units use the same type of heating steam source. Units 3 and 4 have the same rated parameters, and their parameters are controlled similarly during deep peak shaving. Furthermore, the parameters and layout of the pipeline from the screen to the heating source are identical. Therefore, when the heating capacity of Unit 4 is insufficient, the pipeline from the screen to the heating steam source of Unit 3 can be preheated, drained, and put into operation sequentially. By maintaining the heating steam source pressure regulating valve at a certain opening, the insufficient heating flow of a single unit can be compensated. Because the main steam pressure of the two units is controlled similarly during deep peak shaving, and the pipeline from the screen to the heating source is equipped with a check valve, and the heating pipeline between the two units has a smaller diameter, a longer length, and relatively higher resistance, the steam from the screen will not cross-flow.

[0042] Specifically, in the multi-unit coordinated operation mode of the power plant, Units 3 and 4 are identical units with completely consistent rated parameters. Their operation control strategies remain highly synchronized during periods of deep peak shaving, and the main steam pressure, superheater outlet parameters, and thermal system configurations of the two units are all at similar levels. Furthermore, the piping from the superheater to the heating system is designed to be completely symmetrical, with key parameters such as pipe diameter, wall thickness, valve configuration, pipe routing, and length all remaining consistent, ensuring excellent thermal matching. This homogeneous design provides a reliable physical basis for the parallel operation of the heating systems between the two units.

[0043] When Unit 4's high-load heating demand causes the steam source regulation capacity of the shielding system to approach its limit (e.g., the heating steam source pressure regulating valve is fully open), the steam supply capacity of a single unit cannot meet the continuously increasing flow demand. In this case, the adjacent unit support mechanism can be activated. Operators use the shielding system of Unit 3 to the heating steam source pipeline as a backup heat source path, and perform connection, warm-up, and condensate drainage operations sequentially according to standard operating procedures. The warm-up process uses a slow pressure increase to ensure a uniform rise in pipeline metal temperature and avoid thermal stress caused by excessive temperature differences. The condensate drainage operation completely removes condensate from the pipeline to prevent water hammer during commissioning. After confirming that the pipeline is safe and the temperature field is uniform, the heating isolation valve and pressure regulating valve on the Unit 3 side are gradually opened to smoothly connect its heating path to the heating main pipeline system.

[0044] During parallel operation, multiple safeguards have been implemented in the system design to prevent steam backflow or mutual interference between the two units: First, high-performance check valves are installed on the heating outlet pipelines of each unit to ensure that steam flows only unidirectionally to the heating main pipe, preventing reverse flow; second, the connecting pipelines between the two units have relatively small diameters and long routes, creating high flow resistance, preventing large-scale steam cross-flow even with a small pressure difference between the two units; furthermore, under deep peak-shaving conditions, the main steam pressure and screen pressure control targets of the two units are basically the same, with minimal thermodynamic potential difference, further reducing the risk of steam cross-flow. Therefore, by maintaining the heating control valve of Unit 3 at a fixed opening, it can stably output a certain flow rate of steam, effectively supplementing the heating gap of Unit 4, achieving coordinated steam supply from both units, significantly improving the overall heating capacity of the system, and without affecting the safe operation of either unit. This method, as a flexible and reliable means of capacity expansion, can be implemented quickly without shutting down the plant, significantly improving the power plant's heat supply guarantee capability under complex operating conditions.

[0045] It is known that the measures listed in steps S1 to S4 that can increase the heating flow rate highlight timeliness and economy, and are particularly suitable for situations where the heating flow rate is short-term or slightly insufficient. This temporary response strategy through operation mode adjustment can play an effective and timely role in ensuring supply on the basis of normal unit operation, and has zero investment cost.

[0046] S5 involves conducting resistance analysis on the pipe and valve structure of the heating system, locating high-resistance areas, and replacing pipes or valves with smaller diameters or optimizing the pipe layout through design calculations or experimental verification to increase the heating flow rate.

[0047] Understandably, this involves optimizing the structure of pipes and valves in the heating system. This involves resistance analysis of each pipe and valve in the heating system to identify the areas with the greatest resistance; verifying the design selection through design calculations or experiments; replacing pipes and valves with smaller diameter pipes or optimizing the pipeline layout to achieve the expected heating flow rate.

[0048] Understandably, the process involves collecting geometric parameters and operating condition data of each pipe section and valve in the heating system, constructing a pipe and valve structural resistance model, inputting pipe and valve design parameters, outputting the resistance distribution along the pipe and valve at each node, and identifying high-resistance sections. Based on the model analysis, the flow capacity of key pipe and valve nodes is compared with the actual flow rate and the design flow rate. When the actual heating flow rate is detected to be significantly lower than the target value and the regulating valve tends to be fully open, the resistance extreme point is located, confirming that a certain key pipe and valve component is the source of the system's maximum resistance. Combining the historical use of the pipeline with the current operating conditions, the original design application scenario of the pipe and valve is determined, and a diagnostic conclusion is output.

[0049] In one embodiment of the present invention, the structure of the heating system's pipes and valves is optimized. Resistance analysis is performed on the structure of each pipe and valve in the heating system. The auxiliary steam pipeline from the screen to the auxiliary steam pipe is led out from the screen header inside the fifteenth-floor roof, using a reducer sleeve. The inlet pipe specification is φ114×25.4mm, and the outlet pipe specification is φ89×12.7mm. The diameter of the auxiliary steam regulating valve PSA-7 from the screen to the auxiliary steam pipe is relatively small, at 25.4mm; while the diameter of the heating pipeline from the eighth-floor screen to the auxiliary steam pipe is 250mm. It can be seen from the above that the main reason for the limited steam flow is that the original auxiliary steam pipeline from the screen to the auxiliary steam pipe was designed for auxiliary steam users, with a small pipe inner diameter and small valve flow rate. Now, after being converted to heating, the flow rate is significantly insufficient, failing to meet the design heating flow rate of 40t / h of the heating desuperheater and pressure reducer, reaching a maximum of only 28t / h. Furthermore, the point of greatest resistance in this group of pipes and valves is the auxiliary steam regulating valve PSA-7 from the screen to the auxiliary steam pipe.

[0050] Specifically, against the backdrop of continuously increasing heating demand, the pipe and valve structures of the original heating system have gradually revealed insufficient flow capacity, becoming a key bottleneck restricting the increase of heating flow rate. To fundamentally solve this problem, it is necessary to conduct a systemic flow resistance analysis on the key pipe sections and valves of the entire heating system, identify high-resistance areas, and formulate targeted structural optimization schemes. Taking the "screen-to-auxiliary steam" pipeline as an example of a path for converting it into a heating steam source, this pipeline was originally designed to supply steam to the auxiliary steam system, and its operating parameters and flow capacity were matched according to the auxiliary steam load, without considering the demand for large-scale external heating. With the change of system function, this path has been reused as an important heating steam source during deep peak shaving, but its original structure can no longer meet the high flow rate requirements under modern heating conditions.

[0051] Detailed structural analysis shows that the pipeline originates from the superheater header inside the fifteenth-floor shed, using a reducer-type bushing connection. The inlet pipe specification is φ114×25.4mm (inner diameter approximately 63.2mm), and after reduction, the outlet pipe is φ89×12.7mm (inner diameter approximately 63.6mm), resulting in a relatively small overall flow area. More importantly, the superheater-to-gas-source regulating valve on the pipeline, in one embodiment of this invention, is an auxiliary steam regulating valve PSA-7, with a valve core diameter of only 25.4mm (1 inch), far smaller than the size of the downstream heating pipeline. In contrast, the main heating pipeline on the eighth floor of the plant has a designed diameter of 250mm, providing ample transport capacity. Hydraulic calculations and comparisons with actual operating data show that when steam flows through the PSA-7 valve, the local resistance coefficient increases sharply, creating a significant throttling effect. This means that even with an increase in upstream main steam pressure, the downstream flow rate cannot be effectively increased. The system's maximum heating capacity is limited to approximately 28 t / h, far below the rated flow of 40 t / h supported by the desuperheater and pressure reducer design, which severely restricts the expansion potential of the heating system.

[0052] Further resistance distribution simulations revealed that the PSA-7 regulating valve, located between the control panel and the auxiliary steam valve, represents the extreme resistance point in the entire pipeline. Its small-diameter structure generates a significant pressure drop under high flow conditions, becoming a bottleneck restricting system performance. Furthermore, multiple pipe diameter reductions, numerous bends, and mismatched valve types (such as using gate valves instead of full-bore ball valves) exacerbate flow losses. Therefore, relying solely on operational-side adjustments (such as increasing main steam pressure or activating a standby desuperheating station) is insufficient to overcome this physical bottleneck. System structural optimization is necessary. It is recommended to replace the PSA-7 valve with a large-diameter regulating valve (e.g., DN100 or larger) and to perform equal-diameter expansion modifications on the upstream and downstream pipelines to eliminate necking sections and create flow capacity matching heating demand. While this structural optimization must be implemented during unit shutdowns, it fundamentally eliminates flow limitations, improves the long-term stability and scalability of the system, and lays a solid foundation for future heating business development.

[0053] Therefore, after design calculations, the PSA-7 regulating valve from the screen to the auxiliary steam was selected and replaced with a new valve with a larger diameter during the shutdown of Unit 4. After replacement, its flow performance was significantly improved. Under the 30% deep peak shaving condition of a heating pressure of 1.25 MPa and a heating flow rate of 15 t / h, the average opening degree of the PSA-7 regulating valve before and after replacement was 73% and 37%, respectively. Under the 30% deep peak shaving condition of a heating pressure of 1.35 MPa and a heating flow rate of 26 t / h, the average opening degree of the PSA-7 regulating valve before and after replacement was 93% and 75%, respectively, which can meet the current heating demand and leave a certain adjustment margin.

[0054] S6, during unit shutdown, adds a new heating pipeline from the same source as the existing heating steam source and operates in parallel with the original pipeline to increase the steam source delivery capacity.

[0055] It is understandable that a new heating steam source pipeline will be added. The shutdown opportunity will be used to add a new pipeline of the same source to the existing heating steam source pipeline.

[0056] In one embodiment of the present invention, since the steam source used for boiler soot blowing is the same as the heating steam source in deep peak shaving, the normal soot blowing pressure is 20 bar and the soot blowing flow rate is about 20 t / h, which can completely make up for the heating needs of the boiler. A steam pipeline is led from the boiler soot blowing steam source pipeline to the boiler heating pipeline, which can expand the capacity of the boiler to the heating steam source and increase the heating flow rate.

[0057] Specifically, in the operation system of a thermal power plant, both the boiler soot blowing system and the external heating system during deep peak shaving draw steam from the screen-type superheater (screen superheater). They share the same steam source and are compatible in terms of thermodynamic parameters. Under normal operation, the steam pressure used for boiler soot blowing is approximately 20 bar, with a peak flow rate of about 20 t / h per cycle. Soot blowing is intermittent, with each cycle only targeting a portion of the heated surfaces for a short period, resulting in a relatively low average steam consumption. In contrast, under deep peak shaving conditions, the demand for external heating is continuous and stable, especially during the high-load period in winter, when the heating flow rate often approaches or exceeds the system design limit. Because the steam used for soot blowing is consumed periodically and discontinuously, its source is idle or operating at low load during non-soot blowing periods, resulting in significant redundancy in flow capacity.

[0058] Based on this operational characteristic, the potential of the sootblowing steam source can be fully explored and utilized as a supplementary heat source for the heating system. The specific plan is as follows: a steam pipeline is drawn from the boiler sootblowing main pipe and connected to the existing shielded heating main pipe system via an isolation valve, regulating valve, and condensate drain device, forming an independent auxiliary heating path. When the main heating path cannot meet high flow demands (e.g., heating demand exceeding 28 t / h) due to high valve resistance or insufficient regulating capacity, this backup path can be activated. Under the premise of ensuring safe sootblowing of the boiler, the steam originally used for sootblowing can be directionally transported to the heating system. Since the sootblowing steam source itself has an instantaneous steam supply capacity of over 20 t / h, it can serve as a "flowing reserve" for the heating system, effectively making up for the current heating capacity gap and increasing the total heating flow rate to close to the design value of 40 t / h.

[0059] This capacity expansion plan offers significant technical and economic advantages: First, it eliminates the need for new steam sources or large-scale modifications to the main steam system, utilizing existing high-parameter steam resources for multi-purpose use and improving energy efficiency. Second, the soot blowing system itself possesses comprehensive pressure reduction, stabilization, and control functions, allowing new pipelines to reuse its regulatory logic, resulting in low system integration difficulty. Third, by installing dual-path isolation valves and check valves, the heating and soot blowing systems can be ensured to operate independently without interference, automatically cutting off the heating supply during soot blowing to guarantee boiler safety. Furthermore, this plan can be implemented during unit shutdown and maintenance, with a short construction period, low investment cost, and a significant increase in heating capacity immediately after implementation.

[0060] In the future, the control logic can be further optimized to achieve intelligent switching between soot blowing and heating: automatically switching to heating mode during non-soot blowing periods and quickly isolating the heating path when a soot blowing command is triggered to avoid steam backflow or pressure fluctuations. Simultaneously, by installing flow metering devices, precise control of the supplementary steam and energy consumption statistics can be achieved. This solution not only solves the current bottleneck problem of limited heating flow but also provides an innovative path for power plants to achieve multi-objective coordinated operation of "ensuring safety, improving efficiency, and increasing heating supply" under the background of deep peak shaving.

[0061] It is understood that the measures in steps S5 and S6 improve the parts of the heating system with the greatest resistance through local optimization, which has a more significant effect on increasing the heat flow rate. Furthermore, it does not require changing the current operating mode of the heating system, and has the advantages of high feasibility, low investment, and high safety. Depending on the location of the local optimization, the optimization work may be completed while the unit or heating system is running normally, and even if shutdown is required for optimization, the work cycle is very short.

[0062] Furthermore, this method also includes: S7, overall upgrade of the heating system. This involves selecting a suitable steam source, changing the heating method, and redesigning and reconstructing the entire heating system to meet the significantly increased heating demand.

[0063] In one embodiment of the invention, the heating demand from the plant's users shows a year-on-year increasing trend. If the heating business develops significantly in the future, causing the existing heating system to face severe supply constraints, the plant plans to upgrade the entire heating system. After feasibility verification, measures such as expanding the diameter and increasing the capacity of the heat reheat valve and throttling the medium-pressure regulating valve will be taken to solve the problem of insufficient heating flow once and for all. Thus, the goal of increasing the heating flow from a minor response to a significant upgrade is fully achieved.

[0064] Specifically, in recent years, with the expansion of surrounding industrial parks and the extension of the city's centralized heating network, the heating load of this plant has shown a continuous growth trend, with an average annual growth rate exceeding 8%. Currently, while optimizing operations, utilizing backup circuits, and paralleling steam sources from adjacent units can alleviate temporary heating shortages, these measures are mostly localized solutions. Limited by the physical bottlenecks of the existing system architecture (such as small-diameter valves, high-resistance pipelines, and upper limits on steam source pressure), the potential for improvement is nearing its limit. If future heating demand continues to expand, especially in scenarios involving extreme cold waves or the connection of new major regional projects, the existing heating system will struggle to meet peak load requirements, potentially leading to widespread pressure drops, insufficient flow, or even heating outages, severely impacting user production safety and livelihood security.

[0065] To fundamentally resolve the contradiction between heating capacity and demand growth, and to achieve sustainable and highly reliable external energy supply, the plant has initiated a long-term plan for a comprehensive upgrade of its heating system. This upgrade project is not a simple equipment replacement or partial expansion, but a top-level design based on the reconstruction of the entire plant's thermal system, aiming to create a modern heating system that meets the development needs of the next 10-15 years. Based on preliminary technical demonstrations and feasibility studies, a series of systematic transformation measures are proposed: First, the diameter and capacity of the reheat (hot section reheat steam) supply pipeline will be expanded, and the original small-diameter pipes and valves will be replaced with large-diameter (such as DN300 and above) high-flow-capacity pipe and valve assemblies, significantly reducing flow resistance and improving the main steam source delivery capacity; Second, the turbine operation mode will be optimized by adjusting the throttling characteristics of the intermediate-pressure regulating valve, so as to reasonably release the heating potential of reheat steam while ensuring the safety of the unit, and realize flexible decoupling of heat and power loads; At the same time, a new high-temperature and high-pressure desuperheating and pressure reducing station will be built, the layout of the heating main pipeline will be optimized, redundant passages will be added, and an intelligent dispatch and control system will be built to comprehensively improve the system's regulation accuracy, response speed, and operational safety.

[0066] Upon completion of this comprehensive upgrade project, the maximum transmission capacity of the heating system will increase significantly from the current less than 30 t / h to over 60 t / h, fully covering all current and foreseeable future heating demands. More importantly, the new system possesses greater flexibility and scalability, capable of adapting to diverse energy supply requirements across different seasons and user types, truly achieving a "one-and-done" solution to the fundamental problem of insufficient heating flow. From this point forward, the plant's approach to improving heating capacity has undergone a strategic transformation from "passive response and incremental adjustments" to "proactive planning and significant leaps," not only ensuring the stability of regional energy supply but also opening up new profit growth points for the power plant in the context of deep peak shaving in the electricity market, comprehensively achieving the goal of increasing heating flow from short-term emergency response to long-term sustainable development.

[0067] It is known that step S7 is mainly to cope with the significantly increased heating demand in the future. In order to ensure the implementation of the overall upgrade work, the units and heating system must be completely or partially shut down at that time. The work cycle is long, but it can achieve a permanent effect. The increase in heating flow is significant and cannot be compared with other measures. It is suitable for thermal power plants whose heating business development needs are severely constrained by the existing heating system.

[0068] The present invention provides a method for increasing the heat supply flow of a combined heat and power (CHP) unit, which covers the entire process from valve status diagnosis and steam source pressure regulation to system structure optimization. This significantly improves the timeliness and economy of heat supply flow regulation, enhances the system's adaptability to demand fluctuations while ensuring safe and reliable heating, and provides a complete and feasible technical path for the continuous improvement of the heating capacity of CHP units.

[0069] In summary, the contradiction between limited heat supply and unmet demand is becoming increasingly prominent in the development of thermal power plant heating services. Once heating demand increases to a certain level, improving heat supply becomes an urgent issue. This invention proposes a systematic method to increase heat supply, employing strategies ranging from minor adjustments to major upgrades to effectively ensure heat supply. Compared to traditional heating system optimization and upgrade schemes, this method offers more comprehensive heat supply assurance measures, covering everything from temporary operational adjustments to long-term solutions for overall system upgrades. While ensuring sufficient heat supply capacity, this method employs a series of highly effective and targeted approaches, effectively reducing costs and construction time, and achieving more precise and efficient increases in heat supply. For older units facing shutdown, or units where heat demand only slightly exceeds supply capacity during certain periods, this invention provides a series of more timely and economical operational adjustment methods, namely increasing steam source pressure, activating backup heating desuperheating stations, and paralleling adjacent units with the same type of steam source, which can alleviate insufficient heat supply in a timely and effective manner at zero cost. This invention provides a highly feasible, low-investment, and safe method for local optimization of pipe and valve structures. Specifically, it identifies the areas of greatest resistance in the structure of each pipe and valve in the heating system and replaces the valves at those locations or optimizes the pipe layout at those locations to achieve the expected heating flow rate. Depending on the specific area to be optimized, the optimization can be completed even during normal operation of the unit or heating system. Even if downtime is required for optimization, the work cycle is very short.

[0070] This invention also provides a system 10 for increasing the heat supply flow of a combined heat and power unit, such as... Figure 3 As shown, the system 10 includes: The valve status check and steam-water loss control module 100 is used to check and adjust the opening status of all shut-off valves and regulating valves in the heating pipeline, troubleshoot pipeline leaks, check the opening degree and internal leakage of the drain valves, adjust them to allow only a small amount of steam to be discharged, confirm that the drain is working properly and perform maintenance to reduce system steam-water loss. The steam source pressure boosting module 200 is used to increase the pressure of the heating steam source. For superheated steam sources, it is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load. The standby desuperheating station commissioning module 300 is used to commission the standby heating desuperheating station. It sequentially performs connection, pipe warming, drainage and commissioning operations, and reduces system flow resistance by increasing the flow area of ​​the desuperheating station. The adjacent unit steam source parallel operation module 400 is used to operate the same type of heating steam source pipeline of the adjacent unit in parallel, and complete the warm-up, drainage and commissioning in sequence. It further reduces the system resistance by increasing the flow area of ​​the steam source side pipeline. The Pipe and Valve Resistance Analysis and Structure Optimization Module 500 is used to perform resistance analysis on the pipe and valve structure of the heating system, locate high-resistance parts, and replace pipes or valves with smaller diameters or optimize the pipeline layout through design calculations or test verification to increase the heating flow rate. The Homogeneous Heating Pipeline Capacity Expansion Module 600 is used to add a new Homogeneous Heating Pipeline to the existing heating steam source during unit shutdown, and to operate in parallel with the original pipeline to increase the steam source delivery capacity.

[0071] This invention discloses a system for increasing the heat supply flow rate of a combined heat and power (CHP) unit. By constructing a modular collaborative control system integrating valve status diagnosis, steam source pressure regulation, standby desuperheating station operation, and adjacent unit steam source compensation, it effectively solves the core problems of lagging heat supply regulation response, insufficient system flexibility, and high retrofit investment in existing technologies. This device achieves fully automated management of the entire process from operational status monitoring and precise parameter control to intelligent system optimization, significantly improving the accuracy of heat supply flow rate regulation and the system's self-adaptive capability. While ensuring safe and reliable heating, it also enhances the unit's operational economy, providing a complete technical solution for CHP systems to cope with complex operating conditions.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for increasing the heat supply flow rate of a combined heat and power (CHP) unit, characterized in that, include: S1. Check and adjust the opening status of all shut-off valves and regulating valves in the heating pipeline, check for pipeline leaks, check the opening of the drain valve and internal leakage, adjust it to only a small amount of steam discharge, confirm that the drain is working properly and perform maintenance to reduce system steam and water loss. S2 increases the pressure of the heating steam source. For superheated steam sources, this is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load. S3, put the standby heating desuperheating station into operation, and perform the connection, pipe warming, drainage and commissioning operations in sequence to reduce the system flow resistance by increasing the flow area of ​​the desuperheating station; S4, the same type of heating steam source pipelines of adjacent units are operated in parallel, and the warm-up, drainage and commissioning are completed in sequence. The system resistance is further reduced by increasing the flow area of ​​the steam source side pipeline. S5. Conduct resistance analysis on the pipe and valve structure of the heating system, locate high-resistance parts, and replace pipes or valves with smaller diameters or optimize the pipe layout through design calculations or test verification to increase the heating flow rate. S6, during unit shutdown, adds a new heating pipeline from the same source as the existing heating steam source and operates in parallel with the original pipeline to increase the steam source delivery capacity.

2. The method as described in claim 1, characterized in that, S1 includes: Input valve control commands and field feedback signals, compare the set opening degree of the shut-off valve and the actual position of the regulating valve; if there is a deviation, output an alarm and trigger a maintenance work order to ensure that all main valves are opened to the correct position; Input pipeline pressure, flow rate, and inspection images to identify whether there are leaks in the heating pipeline; if abnormal pressure drop or steam leakage is detected, output leak location information and generate pipeline switching and isolation repair instructions; Input the steam trap opening, steam discharge, and steam trap operating status data to determine if there is over-opening or internal leakage; if a large amount of steam is found to be discharged, output an adjustment command to control the steam discharge to a trace amount of steam, and initiate a bypass throttling and isolation troubleshooting process for the faulty steam trap.

3. The method as described in claim 1, characterized in that, S2 includes: Real-time monitoring of heating flow and main steam pressure. When the heating flow is at a high level and the main steam pressure is low, it is determined that the heating system's adjustment capacity is limited. At this time, the pressure regulating valves of the heating steam source and the desuperheating station tend to be fully open, and the system issues an early warning signal that the heating pressure is difficult to maintain. Based on the early warning information, a control command to increase the main steam pressure is generated. By adjusting the boiler operating parameters, the main steam pressure is appropriately increased to restore the control margin of each regulating valve on the heating side, thereby increasing the pressure of the heating main pipe and ensuring a stable supply of heat flow. Continuously monitor the response status of heating pressure and flow. Once the system is confirmed to have returned to normal, output a regulation completion signal and simultaneously assess whether the main steam pressure is close to the upper limit of safe and economical operation of the unit. If it is close, stop further pressure increase to ensure that the unit's operational safety is not sacrificed while guaranteeing heating capacity.

4. The method as described in claim 1, characterized in that, The S3 includes: Real-time collection of heating main pipe pressure data. When the heating pressure is detected to drop abnormally to below the critical value, and the user-side valves continue to open and the flow demand remains high, making it difficult for the pressure to rise, it is determined that the main desuperheating station has insufficient flow capacity and outputs a system blockage warning. Start the standby heating desuperheating station, and sequentially perform the connection, pipe warming, drainage and commissioning operations. Collect the valve opening and pressure response data of the standby desuperheating station. After it is opened to the fixed adjustment opening, the system recognizes that the flow area has increased, the flow resistance has decreased, and the pressure of the heating main pipe begins to rise. The system continuously monitors the recovery trend of heating pressure. When the pressure rises back to the normal operating range and the valves on the user side gradually close due to the satisfaction of demand, it collects data on the opening changes of the regulating valves on the heating steam source side and the desuperheating station to confirm the recovery of its control margin. The system outputs a pressure stabilization signal to complete dynamic adjustment.

5. The method as described in claim 1, characterized in that, The S4 includes: Monitor the current heating demand and supply status of the unit. When it is detected that the heating flow of a single unit is insufficient and the regulating valve is close to being fully open, it is determined that the heating capacity of the unit has reached the upper limit and outputs a signal to start the support of the adjacent unit. Call the backup channel of the adjacent unit of the same type to the heating pipeline, perform pipe warming, drainage and commissioning operations, collect pipeline temperature and pressure data to confirm that the parallel connection conditions are met, open the heating steam source pressure regulating valve to a fixed opening, the system recognizes the increase in total heating flow area and realizes flow compensation. Continuously collect steam pressure, flow rate, and valve status data on both sides of the system. Utilize the natural flow resistance formed by the pipeline check valve and the long-distance arrangement of small-diameter pipes to prevent steam backflow, ensuring the independent and stable operation of the two thermal systems. The system outputs a status confirmation signal indicating improved heating capacity and no risk of crossflow.

6. The method as described in claim 1, characterized in that, The S5 includes: Collect geometric parameters and operating condition data of each pipe section and valve in the heating system, construct a pipe and valve structural resistance model, input pipe and valve design parameters, output the friction and local resistance distribution of each node, and identify high-resistance sections. Based on the model analysis of the flow capacity of key nodes of pipe valves, the actual flow rate is compared with the design flow rate. When the actual heating flow rate is detected to be significantly lower than the target value and the regulating valve tends to be fully open, the resistance extreme point is located, and a certain key pipe valve component is identified as the source of the system's maximum resistance. Based on the historical use of the pipeline and its current operating conditions, determine the original design application scenario of the valve and output a diagnostic conclusion.

7. The method as described in claim 1, characterized in that, The S6 includes: Collect boiler soot blowing system operating parameters, identify the pressure and flow status of soot blowing steam source, confirm that it is the same source as the shielded heating steam source during deep peak shaving, and that the soot blowing pressure is stable and the flow is sufficient during normal operation, and that it has the potential to be used as a backup heating steam source. Based on the shared steam source characteristics, a connection channel model from the soot blowing steam source to the heating pipeline is constructed. The pipeline connection location, valve configuration and control logic are input. The simulation and verification are performed to show that during non-working periods or low demand periods of soot blowing, the soot blowing steam can be directionally delivered to the heating system to realize the parallel expansion of the steam source. After the system performs steam source switching or parallel steam supply operation, it monitors the pressure and flow changes of the heating main pipe in real time. When it detects that the heating capacity has increased and the system pressure tends to stabilize, it outputs a confirmation signal that the soot blowing steam source has been successfully replenished, thus completing the dynamic enhancement of the heating flow.

8. The method as described in claim 1, characterized in that, The method further includes: Collect historical annual heating load data, analyze the trend of user demand changes, and when it is detected that the heating demand continues to grow and the existing system is approaching or reaching its flow limit under peak conditions, output an early warning signal that the system supply capacity will be insufficient. Based on future load forecasts and existing system bottleneck analysis, a model of the overall upgrade scheme for the heating system is constructed. Modification parameters such as expanding the diameter of the heat reheat valve and throttling the medium-pressure regulating valve are input, and technical, economic and feasibility simulations are conducted to verify the technical, economic and feasibility, and a system-level capacity expansion optimization strategy is generated. After confirming the feasibility of the upgrade plan, a system reconfiguration command is output, and engineering modifications such as expanding the diameter and increasing the capacity of the heat recovery pipeline valves and adjusting the operation mode of the medium-pressure regulating valve are initiated. After the implementation is completed, the effect of improving the heating capacity of the entire system is monitored, and a final status confirmation signal is output.

9. A system for increasing the heat supply flow rate of a combined heat and power unit, characterized in that, include: The valve status check and steam loss control module is used to check and adjust the opening status of all shut-off valves and regulating valves in the heating pipeline, troubleshoot pipeline leaks, check the opening degree and internal leakage of the drain valves, adjust them to allow only a small amount of steam to be discharged, confirm that the drain is working properly and perform maintenance to reduce system steam loss. The steam source pressure boosting module is used to increase the pressure of the heating steam source. For superheated steam sources, it is achieved by increasing the main steam pressure; for cold reheat, hot reheat, or turbine extraction steam sources, the steam source pressure is increased by increasing the unit load. The backup desuperheating station activation module is used to activate the backup heating desuperheating station. It sequentially performs connection, pipe warming, drainage and activation operations, and reduces system flow resistance by increasing the flow area of ​​the desuperheating station. The adjacent unit steam source parallel operation module is used to operate the same type of heating steam source pipeline of the adjacent unit in parallel, and complete the warm-up, drainage and commissioning in sequence. The system resistance is further reduced by increasing the flow area of ​​the steam source side pipeline. The pipe and valve resistance analysis and structure optimization module is used to perform resistance analysis on the pipe and valve structure of the heating system, locate high resistance parts, and replace pipes or valves with smaller diameters or optimize the pipe layout through design calculations or test verification to increase the heating flow rate. The homogeneous heating pipeline capacity expansion module is used to add a new homogeneous heating pipeline to the existing heating steam source during unit shutdown, and to operate in parallel with the original pipeline to increase the steam source delivery capacity.

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