A single vapor source cascade heat supply system and method based on vapor compression

Abstract

This invention discloses a single steam source cascade heating system and method based on steam compression. The system includes: a basic heating unit with a primary side and a secondary side; the inlet of the primary side is connected to a flow-diversion regulating unit, and the inlet of the secondary side is connected to the primary heating network return water pipeline, used for primary heat exchange with the primary heating network return water using the first flow-diversion to obtain the primary heating network return water; the inlet of the steam compressor unit is connected to the flow-diversion regulating unit; the peak heating unit has a first side and a second side; the inlet of the first side is connected to the steam compressor unit, used for inputting the compressed second flow-diversion; the inlet of the second side is connected to the secondary side outlet, used for introducing the primary heating network return water, and using the compressed second flow-diversion to perform secondary heat exchange with the primary heating network return water to obtain the primary heating network supply water; this invention can heat the heating network return water to the target supply water temperature using only medium and low pressure exhaust steam with a single parameter, achieving a stable supply of primary heating network water.

Description

Technical Field

[0001] This invention belongs to the field of combined heat and power and district heating technology, and particularly relates to a single steam source cascade heating system and method based on steam compression. Background Technology

[0002] In the field of combined heat and power (CHP), the exhaust steam from the intermediate-pressure cylinder of the steam turbine (typically at 0.2-0.4 MPa absolute pressure) is a common heat source for heating the circulating water in the heating network. This steam has already performed some work within the turbine; utilizing the remaining heat for heating helps achieve cascaded energy utilization and improves the overall energy efficiency of the power plant. However, due to steam pressure limitations, its corresponding saturation temperature is limited; for example, at 0.25 MPa absolute pressure, the saturation temperature is only about 127°C. Considering the necessary heat transfer difference between heat exchangers, the actual temperature achievable to heat the return water in the heating network is usually only between 110°C and 120°C.

[0003] With the continuous expansion of centralized heating networks, many heating networks require supply water temperatures of 130℃ or even above 150℃ to meet the heating demands of long-distance transmission and end-users. Faced with this temperature gap, traditional solutions typically include two approaches: one is to open extraction ports at higher pressure stages of the steam turbine to draw steam with higher parameters as a peak heat source; the other is to directly draw fresh steam generated by the boiler, depressurize and reduce its pressure, and then integrate it into the heating system. The first approach requires modifications to the steam turbine itself, which is not only costly and difficult to implement, but also increases the extraction of high-quality steam, leading to a decrease in the turbine's power generation output. While the second approach can quickly raise the heating temperature, directly using fresh boiler steam to heat the network return water essentially uses high-grade heat energy to complete a low-grade heating task, resulting in significant energy loss from the perspective of the second law of thermodynamics, making the energy utilization method less than ideal.

[0004] More importantly, both of the aforementioned improvement schemes introduce a second steam source with different parameters, transforming the heating system from a single steam source to a multi-steam source structure. This not only increases the complexity of the system equipment and the difficulty of operation and scheduling, but also poses challenges to the flexible adjustment of heating load. When the heating network demand fluctuates, how to coordinate the flow distribution of multiple steam sources and how to avoid parameter disturbances are problems that urgently need to be solved in existing technologies.

[0005] Therefore, how to make full use of the existing single low-grade exhaust steam resource to achieve a stable supply of high-temperature hot water at 150℃ and above, and ensure that the system has good regulation capability and operating economy, without introducing additional high-grade steam source or changing the turbine body structure, has become a technical challenge that needs to be overcome by those skilled in the art.

[0006] Therefore, there is an urgent need for a technological innovation that can deeply tap the potential of single low-grade exhaust steam and achieve high-temperature heating, in order to solve the problems of limited water supply temperature, low energy utilization efficiency, complex system and dependence on multiple steam sources in the existing heating network. Summary of the Invention

[0007] The purpose of this invention is to provide a single steam source cascade heating system and method based on vapor compression. This system can safely and efficiently heat the return water of the heating network to the target supply water temperature by actively improving the thermal quality of medium and low pressure exhaust steam using only a single parameter, thereby achieving a stable supply of water to the primary heating network.

[0008] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a single steam source cascade heating system based on steam compression, comprising: a steam turbine exhaust header, a flow regulation unit, a steam compressor unit, a basic heating unit, a peak heating unit, a parameter measurement unit, and an integrated control unit; The inlet of the turbine exhaust header is connected to the intermediate pressure cylinder exhaust pipeline of the turbine to obtain exhaust steam; The diversion regulating unit is connected downstream of the turbine exhaust header and is used to divert the exhaust steam into a first diversion and a second diversion. The basic heating unit has a primary side and a secondary side. The inlet of the primary side is connected to the diversion adjustment unit for inputting the first diversion. The inlet of the secondary side is connected to the primary heating network return water pipeline for introducing the primary heating network return water and using the first diversion to perform a primary heat exchange with the primary heating network return water to obtain the heating network return water after the primary heat exchange. The inlet of the steam compressor unit is connected to a flow splitting regulating unit, which is used to compress the second flow to obtain a compressed second flow. The peak heating unit has a first side and a second side. The inlet of the first side is connected to the steam compressor unit for inputting the compressed second diverter. The inlet of the second side is connected to the secondary side outlet for introducing the heat network return water after the first heat exchange, and using the compressed second diverter to perform secondary heat exchange with the heat network return water after the first heat exchange to obtain the primary heat network water supply. The parameter measurement unit is located at the second outlet and is used to measure the current primary heating network water supply temperature in real time. The integrated control unit connects the parameter measurement unit, the flow regulation unit, and the steam compressor unit. It is used to adjust the flow ratio of the flow regulation unit and the operating speed of the steam compressor unit in a closed loop according to the deviation between the target water supply temperature and the current primary heating network water supply temperature, so as to achieve a stable output of primary heating network water supply.

[0009] Optionally, the steam compression unit includes a drive unit and a steam compressor driven by the drive unit. Optionally, the drive unit is a speed-increasing gearbox, a small steam turbine, or a variable frequency motor.

[0010] Optionally, the steam compressor is a centrifugal compressor, a screw compressor, or a positive displacement compressor.

[0011] Optionally, a gas-liquid separator is provided on the inlet pipe of the vapor compression unit.

[0012] Optionally, the single steam source cascade heating system based on vapor compression further includes a condensate collection device, which is located at the junction of the primary side outlet pipe and the first side outlet pipe to collect the two outlet waters.

[0013] Optionally, the basic heating unit and the peak heating unit can be any one of a shell-and-tube heat exchanger, a plate heat exchanger, and a plate-and-shell heat exchanger.

[0014] In a second aspect, the present invention provides a single-steam-source cascade heating method based on vapor compression, employing the single-steam-source cascade heating system based on vapor compression as described in the first aspect, characterized in that it includes: The turbine exhaust header draws exhaust steam from the intermediate pressure cylinder of the turbine. The flow splitting control unit splits the exhaust steam to obtain the first flow split and the second flow split; The basic heating unit exchanges heat between the first branch and the primary heat network return water to obtain heat network return water after one heat exchange. The steam compression unit compresses the second stream to obtain the compressed second stream; The peak heating unit performs secondary heat exchange on the compressed second diversion water and the heat network return water after the first heat exchange to obtain the primary heat network water supply. The data acquisition unit collects the current primary heating network water supply temperature in real time; The integrated control unit adjusts the flow ratio of the flow control unit and the operating speed of the steam compression unit in a closed loop based on the deviation between the target water supply temperature and the current primary heating network water supply temperature, thereby achieving a stable output of water from the primary heating network.

[0015] Optionally, the target water supply temperature is not lower than 130°C.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: This invention provides a single-steam-source cascade heating system and method based on steam compression, successfully solving technical problems such as limited heating network water supply temperature, reliance on multiple steam sources, and low energy utilization efficiency in traditional cogeneration heating systems. The system uses exhaust steam from the intermediate-pressure cylinder of the steam turbine as the sole steam source. A flow-dividing regulating unit splits the exhaust steam into two paths. One path directly enters the basic heating unit for the first heat exchange with the primary heating network return water, achieving initial cascade utilization of heat. The other path is compressed and pressurized by the steam compressor unit before entering the peak heating unit, where it undergoes a second heat exchange with the heating network return water after heat exchange in the basic heating unit, thereby raising the primary heating network water supply temperature to over 150°C. During this process, a parameter measurement unit collects the water supply temperature in real time and feeds it back to the integrated control unit. This unit, based on the deviation between the target water supply temperature and the actual temperature, uses a closed-loop adjustment mechanism to adjust the flow-dividing ratio of the flow-dividing regulating unit and the operating speed of the steam compressor unit, achieving coordinated control of flow distribution and steam quality. Compared with existing technologies, this invention can meet high-temperature heating needs by relying solely on a single low-grade exhaust steam, without the need to open an extraction port from a higher pressure stage of the steam turbine or draw new steam from the boiler. This avoids the reduction in steam turbine power generation output and the loss of high-grade steam, significantly improving the efficiency of energy cascade utilization. At the same time, through the dynamic and coordinated adjustment of the split ratio and compressor speed by the integrated control unit, the system can quickly respond to changes in the heating network load and accurately stabilize the water supply temperature at the set value. This overcomes the problems of complex structure and difficult scheduling of multi-steam-source systems, broadens the load adjustment range of the heating system, and has good operational economy and application value. Attached Figure Description

[0017] Figure 1 The diagram shown is a process flow chart of a single steam source cascade heating system based on steam compression in one embodiment of the present invention. In the diagram: 1-Intermediate-pressure cylinder of the steam turbine; 2-Exhaust header of the steam turbine; 3-Flow control valve; 4-Basic heating unit; 5-Steam compressor; 6-Peak heating unit; 7-Primary heating network return water pipeline; 8-Primary heating network supply water pipeline; 9-Basic heating drain pipe; 10-Peak heating drain pipe; 11-Drain collection device; 12-Integrated control unit; 13-Parameter measurement unit; 14-Low-pressure cylinder of the steam turbine; 15-Gas-liquid separator. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0019] Example 1

[0020] like Figure 1 As shown in the figure, this embodiment of the invention introduces a single steam source cascade heating system based on vapor compression, comprising: 2. Steam turbine exhaust header, 3. Flow control unit, 4. Steam compressor unit, 5. Basic heating unit, 6. Peak heating unit, 13. Parameter measurement unit and 12. Integrated control unit; Specifically, the inlet of the turbine exhaust header 2 is connected to the exhaust pipeline of the intermediate pressure cylinder 1 of the turbine to obtain exhaust steam as the sole heat source of the system. The exhaust pressure of the intermediate pressure cylinder is typically 0.2MPa to 0.4MPa absolute pressure, and the temperature is 200℃ to 300℃. This part of the steam has already done some work in the turbine and belongs to low-grade waste heat resources.

[0021] Specifically, the diversion regulating unit (i.e., the diversion regulating valve 3) is connected downstream of the turbine exhaust header 2 to divert the exhaust steam into a first diversion and a second diversion. In this embodiment, the diversion regulating valve 3 is an electrically operated regulating valve, whose opening degree is continuously adjustable within the range of 0% to 100%. In the initial working state, the first diversion accounts for approximately 60% to 80% of the total exhaust steam, and the second diversion accounts for approximately 20% to 40%. The first diversion enters the shell-side inlet of the basic heating unit 4 through the first pipeline, and the second diversion enters the inlet of the steam compressor 5 through the second pipeline.

[0022] Specifically, the basic heating unit 4, i.e., the basic heater type, adopts a shell-and-tube heat exchanger. Its shell side serves as the primary side, connected to the diversion regulating valve 3 for inputting the first diversion flow. The tube side serves as the secondary side, connected to the primary heating network return water pipe 7 via piping. The primary heating network return water, driven by the heating network circulation pump, enters the tube side of the basic heating unit 4 at a temperature of 80°C, undergoing the first heat exchange with the exhaust steam flowing from the intermediate-pressure cylinder in the shell side. After heat exchange, the latent heat of vaporization of the first diversion flow releases and condenses into condensate, which is discharged through the basic heating condensate drain pipe 9 connected to the bottom of the basic heating unit 4, i.e., the primary side outlet. The primary heating network return water is then heated to approximately 115°C, becoming the heating network return water after the first heat exchange, flowing out from the tube side (secondary side) outlet of the basic heating unit 4. Specifically, the steam compression unit includes a drive unit and a steam compressor 5 driven by the drive unit; the drive unit is a speed-increasing gearbox, a small steam turbine, or a variable frequency motor. The steam compressor is a centrifugal compressor, a screw compressor, or a positive displacement compressor. In this embodiment, the steam compressor 5 is a centrifugal electric compressor driven by a variable frequency motor. Its inlet is connected to a flow-dividing regulating valve 3, and its outlet is connected to the shell-side inlet of the peak heating unit 6. The second flow entering the steam compressor 5 is compressed and its pressure is increased to above 0.6 MPa absolute pressure by the compressor, corresponding to a saturation temperature of above 159°C. The compressed high-temperature steam enters the shell-side of the peak heating unit 6 through pipelines. Specifically, a gas-liquid separator is provided on the inlet pipe of the steam compression unit to ensure that the steam entering the steam compressor 5 is dry saturated steam or superheated steam, and to prevent liquid droplets from damaging the impeller.

[0023] Specifically, the peak heating unit 6 also employs a shell-and-tube heat exchanger. Its shell side serves as the first side, connecting to the outlet of the steam compressor 5 for inputting the compressed second stream. The tube side serves as the second side, connecting to the tube outlet of the basic heating unit 4 via pipeline, for introducing the 115°C return water from the heating network after the first heat exchange. Inside the peak heating unit 6, high-temperature steam above 159°C undergoes a second heat exchange with the 115°C return water from the heating network, precisely heating the return water to 150°C, making it the primary heating network supply water that meets heating requirements. This water flows through the tube outlet of the peak heating unit 6 into the primary heating network supply pipe 8 and is then output to the heating network. After heat exchange, the second stream condenses into condensate, which is discharged through the peak heating condensate pipe 10 connected to the bottom of the peak heating unit 6. Both the basic heating condensate pipe 9 and the peak heating condensate pipe 10 are connected to a condensate collection device 11. The two condensates mix and return to the power plant's thermal system via the condensate collection device 11, achieving working fluid recovery.

[0024] Specifically, parameter measurement unit 13 is a temperature sensor installed on the primary heating network water supply pipe 8, located downstream of the outlet of the peak heating unit 6, for real-time measurement of the current primary heating network water supply temperature. The temperature sensor is electrically connected to the input terminal of the integrated control unit 12, transmitting the real-time temperature signal to the integrated control unit 12. The output terminal of the integrated control unit 12 is electrically connected to the actuator of the flow control valve 3 and the variable frequency motor of the steam compressor 5, respectively, for closed-loop adjustment of the flow ratio of the flow control valve 3 and the operating speed of the steam compressor 5 based on the deviation between the target water supply temperature and the current primary heating network water supply temperature.

[0025] In this embodiment, the integrated control unit 12 employs a programmable logic controller (PLC) with an internally preset target water supply temperature of 150°C and runs a PID control algorithm. Its specific control logic is as follows: When the temperature sensor 13 detects that the current water supply temperature is below 150°C, the integrated control unit 12 calculates a positive deviation and then outputs a first control signal to drive the diversion regulating valve 3 to increase the second diversion, i.e., appropriately opening the valve to increase the steam flow into the steam compressor 5, while simultaneously reducing the first diversion flow into the basic heating unit 4. Simultaneously, the integrated control unit 12 outputs a second control signal to the variable frequency motor of the steam compressor 5, increasing the motor speed to maintain the compressor outlet pressure above 0.6 MPa absolute pressure, ensuring that the steam entering the peak heating unit 6 has sufficient enthalpy to heat the hot water to the target water supply temperature. Conversely, when the detected water supply temperature is above 150°C, the integrated control unit 12 outputs a reverse control signal, appropriately closing the diversion regulating valve 3 to reduce the steam flow into the compressor, while simultaneously reducing the compressor speed until the water supply temperature stabilizes within the allowable deviation range of 150°C. Throughout the adjustment process, the adjustment step size of the diversion control valve 3 is controlled to not exceed 5% of the total flow rate in a single operation to ensure the stability of the system adjustment.

[0026] To adapt to the operating requirements under different load conditions, the integrated control unit 12 also stores the performance curves and system characteristic parameters of the steam compressor 5. During the adjustment process, the control unit automatically matches the optimized set value of the compressor speed according to the change in the opening of the diversion regulating valve 3, ensuring that the compressor always operates in the high-efficiency range and avoiding unstable operating conditions such as surge or blockage.

[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art can make appropriate adjustments to the heat exchanger type, control algorithm, and specific parameters in the above embodiments according to actual application scenarios. For example, plate heat exchangers or plate-shell heat exchangers can be used instead of shell-and-tube heat exchangers for the basic heating unit 4 and peak heating unit 6, and fuzzy control algorithms can be used instead of PID control algorithms for the integrated control unit 12. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0028] Example 2

[0029] This invention provides a single-steam-source cascade heating method based on vapor compression, employing the single-steam-source cascade heating system based on vapor compression described in Example 1, comprising: The turbine exhaust header draws exhaust steam from the intermediate pressure cylinder of the turbine. The flow splitting control unit splits the exhaust steam to obtain the first flow split and the second flow split; The basic heating unit exchanges heat between the first branch and the primary heat network return water to obtain heat network return water after one heat exchange. The steam compression unit compresses the second stream to obtain the compressed second stream; The peak heating unit performs secondary heat exchange on the compressed second diversion water and the heat network return water after the first heat exchange to obtain the primary heat network water supply. The data acquisition unit collects the current primary heating network water supply temperature in real time; The integrated control unit adjusts the flow ratio of the flow control unit and the operating speed of the steam compression unit in a closed loop based on the deviation between the target water supply temperature and the current primary heating network water supply temperature, thereby achieving a stable output of water from the primary heating network.

[0030] Furthermore, in combination Figure 1 The specific method is as follows: When this system is working, the exhaust steam from the intermediate-pressure cylinder of the steam turbine is first introduced into the exhaust header. The steam is then divided into two different streams by a flow divider valve. One stream serves as the basic heating stream, i.e., the first stream, and enters the shell side of the basic heater; the other stream serves as the compression and pressure boosting stream, i.e., the second stream, and enters the inlet of the steam compressor.

[0031] On the base heater side, primary return water from the heating network is driven by a circulating pump and enters the tube side of the base heater at a temperature of T1 (80°C). The base heating flow exchanges heat with the tube-side return water in the shell side. After releasing its latent heat of vaporization, the steam heats the heating network water to an intermediate temperature of T2 (115°C), while the steam itself condenses into condensate, which enters the condensate collection device through the condensate pipe.

[0032] Meanwhile, the compressed and boosted steam enters the steam compressor. Driven by a variable frequency motor, the compressor performs work on this steam, increasing its pressure from P1 (0.25 MPa a) to P2 (the saturation temperature Tsat2 corresponding to P2 must be higher than the target supply water temperature T3 of the heating network; for example, if T3 = 150℃, then Tsat2 > 150℃, corresponding to P2 > 0.48 MPa a) to ensure it has sufficient temperature quality to complete the subsequent peak heating task. The compressed high-temperature steam enters the shell side of the peak heater from the compressor outlet.

[0033] Within the peak heater, T2 heat network water from the tube-side outlet of the base heater enters the tube side and undergoes a second heat exchange with high-temperature compressed steam in the shell side. The high-temperature steam ultimately heats the heat network water to the target supply temperature (T3), and then condenses itself into condensate, which enters the condensate collection device through the condensate pipeline. The two condensates are mixed in the collection device and then returned to the power plant's thermal system for working fluid recovery and reuse. Finally, the water is heated to T3.

[0034] Throughout the entire operation, temperature sensors installed on the water supply pipes monitor the actual temperature of the primary heating network's water supply in real time and continuously transmit the signal to the integrated control unit. The integrated control unit compares the measured temperature with the internally set target value and dynamically executes closed-loop regulation based on the deviation between the two. Through the coordinated regulation of the diversion valve and the steam compressor speed, the system can quickly respond to load changes and accurately and stably maintain the water supply temperature at the target water supply temperature T3.

[0035] In summary, although this invention involves electricity consumption, it provides a novel approach to energy regulation. During off-peak periods when spot electricity prices are low, or when power plants need to reduce power generation to ensure heating supply, this solution can serve as an effective and flexible adjustment method. Essentially, it replaces reliance on higher-grade steam with a portion of electrical energy, increasing operational strategy options from the perspective of integrated plant energy management, thus possessing industrial applicability.

[0036] The current mainstream technical solution is to introduce a higher-grade heat source as a "peak heat source," mainly through two approaches: one is to open a higher-pressure extraction port from the intermediate-pressure or high-pressure cylinder of the steam turbine; the other is to directly extract fresh steam from the boiler, and use it after desuperheating and depressurization. While these two approaches are effective, they have inherent drawbacks: the former reduces the turbine's power generation capacity and is subject to limitations in retrofitting; the latter directly consumes the highest-grade steam, making it uneconomical from a plant-wide efficiency perspective. Furthermore, both methods make the heating system dependent on multi-parameter steam sources, increasing system complexity and operational scheduling difficulties. Therefore, a technological innovation that can deeply tap the potential of a single low-grade exhaust steam source to achieve high-temperature heating is also an advantage.

[0037] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0038] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0039] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0040] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A single steam source cascade heating system based on vapor compression, characterized in that, include: Steam turbine exhaust header, flow control unit, steam compressor unit, basic heating unit, peak heating unit, parameter measurement unit, and integrated control unit; The inlet of the turbine exhaust header is connected to the intermediate pressure cylinder exhaust pipeline of the turbine to obtain exhaust steam; The diversion regulating unit is connected downstream of the turbine exhaust header and is used to divert the exhaust steam into a first diversion and a second diversion. The basic heating unit has a primary side and a secondary side. The inlet of the primary side is connected to the diversion adjustment unit for inputting the first diversion. The inlet of the secondary side is connected to the primary heating network return water pipeline for introducing the primary heating network return water and using the first diversion to perform a primary heat exchange with the primary heating network return water to obtain the heating network return water after the primary heat exchange. The inlet of the steam compressor unit is connected to a flow splitting regulating unit, which is used to compress the second flow to obtain a compressed second flow. The peak heating unit has a first side and a second side. The inlet of the first side is connected to the steam compressor unit for inputting the compressed second diverter. The inlet of the second side is connected to the secondary side outlet for introducing the heat network return water after the first heat exchange, and using the compressed second diverter to perform secondary heat exchange with the heat network return water after the first heat exchange to obtain the primary heat network water supply. The parameter measurement unit is located at the second outlet and is used to measure the current primary heating network water supply temperature in real time. The integrated control unit connects the parameter measurement unit, the flow regulation unit, and the steam compressor unit. It is used to adjust the flow ratio of the flow regulation unit and the operating speed of the steam compressor unit in a closed loop according to the deviation between the target water supply temperature and the current primary heating network water supply temperature, so as to achieve a stable output of primary heating network water supply.

2. The single-steam-source cascade heating system based on vapor compression according to claim 1, characterized in that, The vapor compression unit includes a drive unit and a vapor compressor driven by the drive unit.

3. The single steam source cascade heating system based on vapor compression according to claim 2, wherein the driving component is a speed-increasing gearbox, a small steam turbine, or a variable frequency motor.

4. The single steam source cascade heating system based on vapor compression according to claim 3, characterized in that, The steam compressor is a centrifugal compressor, a screw compressor, or a positive displacement compressor.

5. The single-steam-source cascade heating system based on vapor compression according to claim 4, characterized in that, A gas-liquid separator is installed on the inlet pipe of the vapor compression unit.

6. The single-steam-source cascade heating system based on vapor compression according to claim 5, characterized in that, It also includes a drainage collection device, which is installed at the junction of the primary outlet pipe and the first outlet pipe to collect the water from the two outlets.

7. The single steam source cascade heating system based on vapor compression according to claim 6, characterized in that, The basic heating unit and the peak heating unit are any one of shell-and-tube heat exchangers, plate heat exchangers, and plate-and-shell heat exchangers.

8. A single-steam-source cascade heating method based on vapor compression, employing the single-steam-source cascade heating system based on vapor compression as described in any one of claims 1-7, characterized in that, include: The turbine exhaust header draws exhaust steam from the intermediate pressure cylinder of the turbine. The flow splitting control unit splits the exhaust steam to obtain the first flow split and the second flow split; The basic heating unit exchanges heat between the first branch and the primary heat network return water to obtain heat network return water after one heat exchange. The steam compression unit compresses the second stream to obtain the compressed second stream; The peak heating unit performs secondary heat exchange on the compressed second diversion water and the heat network return water after the first heat exchange to obtain the primary heat network water supply. The data acquisition unit collects the current primary heating network water supply temperature in real time; The integrated control unit adjusts the flow ratio of the flow control unit and the operating speed of the steam compression unit in a closed loop based on the deviation between the target water supply temperature and the current primary heating network water supply temperature, thereby achieving a stable output of water from the primary heating network.

9. The single-steam-source cascade heating method based on vapor compression according to claim 8, characterized in that, The target water supply temperature is not lower than 130℃.

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