A dual low-pressure cylinder machine-side coupled nuclear energy system with negative carbon emission and a control method thereof

Abstract

The present application belongs to the technical field of nuclear energy and biomass energy coupling, and provides a double low-pressure cylinder machine side coupled nuclear energy system with negative carbon emission and a control method thereof. The first low-pressure cylinder and the second low-pressure cylinder are connected to a steam main pipe through a first adjusting valve and a second adjusting valve respectively, and a first control valve is arranged between the first low-pressure cylinder and the second low-pressure cylinder on the steam main pipe. The first low-pressure cylinder is connected to a residential heating system through a second control valve. The steam main pipe is connected to a nuclear energy heating reactor through a third control valve. The nuclear energy heating reactor is connected to a reboiler through a fourth control valve. The working states of the first low-pressure cylinder, the second low-pressure cylinder and the nuclear energy heating reactor are controlled through the actions of the valves, and the actions of the valves are controlled according to different working conditions in the heating season and the non-heating season. The problem that the nuclear energy heating reactor is difficult to adapt due to frequent changes in heating load is solved, the overall economy of the system is improved, and the problem that the nuclear reactor needs to be frequently adjusted due to load changes is avoided.

Description

Technical Field

[0001] This invention belongs to the field of nuclear energy and biomass energy coupling technology, and particularly relates to a negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system and its control method. Background Technology

[0002] Because the turbine unit needs to accommodate nuclear steam and biomass boiler steam according to changes in heating load, the upper limit of flow rate is high and the flow rate changes frequently; the unit adopts a dual low-pressure cylinder configuration, and the high-pressure cylinder and low-pressure cylinder are equipped with generators respectively. Each module is independent of each other, and the operation mode is flexible and reliable. If any cylinder fails, it will not affect the operation of the other cylinders.

[0003] Existing nuclear power plant turbine control methods, when applied to architectures with separate shafts for high-pressure and low-pressure cylinders and each with its own independent generator, struggle to achieve real-time power balance between multiple generator load distribution and the slow-dynamic reactor, easily causing fluctuations in primary loop parameters. Furthermore, the strong coupling of steam parameters among multiple units means that single adjustments can easily trigger system oscillations, affecting stability and economy, making it unsuitable for operation under multiple conditions. In addition, post-combustion carbon dioxide capture technology is currently the most suitable technology for carbon emission reduction in thermal power plants, with chemical absorption being the most widely used technology, combining applicability and economy. However, existing power plants generally use internal steam extraction to heat the chemical absorbent for regeneration without introducing an external heat source, preventing thermal power plants from operating at their rated conditions. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a negative carbon emission dual-low-pressure cylinder reactor-side coupled nuclear energy system and its control method. The system controls the operating states of the first low-pressure cylinder, the second low-pressure cylinder, and the nuclear heating reactor through a first regulating valve, a second regulating valve, a first control valve, a second control valve, a third control valve, and a fourth control valve. It also controls the operation of each valve according to different operating conditions during the heating and non-heating seasons. This solves the problem of the nuclear heating reactor being difficult to adapt to due to frequent changes in heating load, accommodates surplus nuclear steam for power generation, improves the overall economic efficiency of the system, avoids the need for frequent adjustments to the nuclear reactor due to load changes, ensures the safe and stable operation of the nuclear reactor, and is suitable for operation under multiple conditions.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system, employing the following technical solution: A carbon-neutral dual-low-pressure cylinder engine-side coupled nuclear energy system includes a high-pressure cylinder and a first condenser connected to one end of a steam header, a first low-pressure cylinder and a second low-pressure cylinder connected to the steam header via a first regulating valve and a second regulating valve, respectively, and a nuclear heating reactor connected to the steam header. A first control valve is installed on the steam header between the first low-pressure cylinder and the second low-pressure cylinder; the first low-pressure cylinder is connected to the residential heating system via a second control valve; the steam header is connected to the nuclear heating reactor via a third control valve; the nuclear heating reactor is connected to the residential heating system and to the reboiler via a fourth control valve; the first low-pressure cylinder is connected to the reboiler via a fifth control valve; the fifth control valve is connected in parallel with both the second and fourth control valves; the reboiler is connected to a carbon dioxide storage tank; the operating status of the first low-pressure cylinder, the second low-pressure cylinder, and the nuclear heating reactor is controlled by the first regulating valve, the second regulating valve, the first control valve, the second control valve, the third control valve, and the fourth control valve, and the operation of each valve is controlled according to different operating conditions during the heating season and non-heating season.

[0006] Furthermore, the steam inlet of the high-pressure cylinder is connected to a biomass boiler, and the steam outlet is connected to a steam header; the high-pressure cylinder, the first low-pressure cylinder, and the second low-pressure cylinder are respectively connected to a first generator, a second generator, and a third generator.

[0007] Furthermore, the steam header is also connected to the first condenser via a third regulating valve.

[0008] Furthermore, the second low-pressure cylinder and the reboiler are connected to a second condenser; the reboiler is sequentially connected to a regeneration tower and an absorption tower; the regeneration tower is connected to the carbon dioxide storage tank.

[0009] To achieve the above objectives, in a second aspect, the present invention also provides a control method for a dual low-pressure cylinder engine-side coupled nuclear energy system with negative carbon emissions, employing the following technical solution: A control method for a carbon-neutral dual-low-pressure cylinder generator-side coupled nuclear energy system, as described in the first aspect, includes: high-temperature, high-pressure steam generated by a biomass boiler enters a high-pressure cylinder to perform work, driving a first generator to generate electricity; exhaust steam from the high-pressure cylinder enters a steam header, and surplus steam from the nuclear heating reactor enters the steam header; the two types of steam are mixed in the steam header, and the mixed low-pressure steam is transported to the low-pressure cylinder to perform work and generate electricity; the steam header is used for emergency response via a first condenser; a first regulating valve controls the steam to enter the first low-pressure cylinder, and a second regulating valve controls the steam to enter the second low-pressure cylinder.

[0010] Furthermore, during the heating season, when all the steam supplied by the nuclear reactor is used for residential heating, the third and fourth control valves are closed, the first regulating valve and the fifth control valve are opened, the second control valve is closed, all the steam in the first low-pressure cylinder is used for the carbon capture system, the second low-pressure cylinder is not started, the second regulating valve is closed, the first control valve is opened, the third regulating valve is opened, and after the steam has finished doing work, it enters the first condenser.

[0011] Furthermore, during the heating season, all the steam supplied by the nuclear reactor is used for residential heating. However, when the steam supplied by the nuclear reactor cannot meet the heating demand, the third and fourth control valves are closed, and the first regulating valve, the fifth control valve, and the second control valve are opened. The steam extraction part of the first low-pressure cylinder is used for the carbon capture system, and part is used for heating. The second low-pressure cylinder is not started, the second regulating valve is closed, and the first and third regulating valves are opened. After the steam has finished doing work, it enters the first condenser.

[0012] Furthermore, when the nuclear reactor steam exceeds the residential heating demand during the heating season, the third control valve is closed and the fourth control valve is opened. During the heating season, part of the nuclear reactor heating steam is used for residential heating, and part enters the reboiler of the carbon capture system for heat exchange. The first regulating valve and the fifth control valve are opened, and the second control valve is closed. All the steam extracted from the first low-pressure cylinder is used for the carbon capture system. The second low-pressure cylinder is not started. The second regulating valve is closed, and the first control valve and the third regulating valve are opened. After the steam has finished doing work, it enters the first condenser.

[0013] Furthermore, during the non-heating season, when all the reactor heating steam is used for low-pressure cylinder generator-side coupling, the fourth control valve is closed, and the third control valve and the first regulating valve are opened. When all the reactor heating steam is used for low-pressure cylinder generator-side coupling, the fifth control valve is opened, the second control valve is closed, and the first control valve and the second regulating valve are opened. All the steam extracted from the first low-pressure cylinder is used for the carbon capture system. After entering the carbon capture system and completing heat exchange with the reboiler, it enters the second condenser.

[0014] Furthermore, when the electricity load increases during the non-heating season, the fourth and third control valves are opened. Part of the nuclear reactor heating steam is used for low-pressure cylinder side coupling, and part is used for the carbon capture system. The first regulating valve is opened, and the fifth and second control valves are closed. The first control valve and the second regulating valve are opened. The biomass boiler steam is used for the turbine to do work. The nuclear reactor heating steam enters the carbon capture system to complete heat exchange with the reboiler and then enters the second condenser.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this invention, a first low-pressure cylinder and a second low-pressure cylinder are connected to a steam header via a first regulating valve and a second regulating valve, respectively. A first control valve is installed on the steam header between the first and second low-pressure cylinders. The first low-pressure cylinder is connected to a residential heating system via a second control valve. The steam header is connected to a nuclear heating reactor via a third control valve. The nuclear heating reactor is connected to a reboiler via a fourth control valve. The first low-pressure cylinder is connected to the reboiler via a fifth control valve. The first regulating valve, the second regulating valve, the first control valve, the second control valve, the third control valve, and the fourth control valve control the operating status of the first low-pressure cylinder, the second low-pressure cylinder, and the nuclear heating reactor, and control the operation of each valve according to different operating conditions during the heating season and non-heating season. This invention solves the problem of nuclear heating reactors being difficult to adapt to due to frequent changes in heating load, accommodates surplus nuclear steam for power generation, improves the overall economic efficiency of the system, avoids the problem of frequent adjustments required by the nuclear reactor due to load changes, ensures the safe and stable operation of the nuclear reactor, and is suitable for operation under multiple operating conditions.

[0016] 2. The present invention features a separate shaft design for the two low-pressure cylinders and the high-pressure cylinder, with each turbine equipped with a generator. Compared with the traditional coaxial design of high and low pressure cylinders, each module is independent of the others, and the unit operates flexibly and reliably. Failure of any cylinder will not affect the operation of the other cylinders. The dual low-pressure cylinder design improves the peak-shaving performance of the unit and can adjust the operating mode according to the heat load demand, flexibly accommodating surplus nuclear steam.

[0017] 3. This invention enables carbon capture via chemical absorption in both heating and non-heating seasons, offering exceptional flexibility. Furthermore, external steam can be introduced to regenerate the chemical absorbent, preventing generator units from operating below rated capacity due to steam extraction losses. It is adaptable to various types of thermal power plants and nuclear reactor couplings, with each thermal system capable of independently performing carbon capture and heating functions, thus improving system stability and safety compared to other systems. Attached Figure Description

[0018] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0019] Figure 1 This is a schematic diagram of the system structure of Embodiment 1 of the present invention; The components are as follows: 1. High-pressure cylinder; 2. First generator; 3. First low-pressure cylinder; 4. Second generator; 5. Second low-pressure cylinder; 6. Third generator; 7. First regulating valve; 8. Second regulating valve; 9. First condenser; 10. Third regulating valve; 11. Absorber; 12. Regeneration tower; 13. Reboiler; 14. Carbon dioxide storage tank; 15. Second condenser; 16. First control valve; 17. Second control valve; 18. Third control valve; 19. Fourth control valve; 20. Fifth control valve. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] To fully utilize nuclear energy and improve the overall economic efficiency of nuclear heating, a nuclear-biomass energy coupling technology is adopted. This involves coupling steam generated by a biomass boiler with steam generated by a nuclear heating reactor to generate electricity. During the heating season, the heat from the nuclear heating reactor is primarily used to meet the heating load, while the biomass power plant serves as a backup and peak-shaving heat source. Surplus steam from the coupled heating reactor is used for power generation, avoiding frequent adjustments to the heating reactor. During the non-heating season, the biomass power plant generates electricity solely through condensation from the coupled heating reactor, without shutting down the nuclear heating reactor, thus fully utilizing the heat from the nuclear heating reactor to improve economic efficiency.

[0023] Because the turbine unit needs to accommodate nuclear steam and biomass boiler steam according to changes in heating load, the upper limit of flow rate is high and the flow rate changes frequently. Therefore, the unit adopts a dual low-pressure cylinder configuration. Furthermore, each of the high-pressure and low-pressure cylinders is equipped with a generator, and each module operates independently, allowing for flexible and reliable operation. A failure in any one cylinder will not affect the operation of the remaining cylinders.

[0024] As described in the background section, the existing control methods for nuclear power plant turbine units, when applied to an architecture where the high-pressure cylinder and low-pressure cylinder are arranged on separate shafts and each has an independent generator, have the following problems: the load distribution of multiple generators and the power between the slow-dynamic reactor are difficult to balance in real time, which can easily cause fluctuations in the primary loop parameters; the steam parameters of multiple units are strongly coupled, and single adjustment can easily cause system oscillations, affecting stability and economy.

[0025] To address at least one of the aforementioned problems, one embodiment of the present invention provides a negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system. Compared to existing designs, this system improves the unit's adjustment capability, offers more flexible operation, achieves rapid and safe power transition, maximizes the unit's operational economy, and can meet the technical requirements of nuclear and biomass energy coupling systems.

[0026] like Figure 1 As shown, the present invention proposes a carbon-neutral dual-low-pressure cylinder engine-side coupled nuclear energy system, including a high-pressure cylinder 1, a first generator 2, a first low-pressure cylinder 3, a second generator 4, a second low-pressure cylinder 5, a third generator 6, a first regulating valve 7, a second regulating valve 8, a first condenser 9, a third regulating valve 10, an absorption tower 11, a regeneration tower 12, a reboiler 13, a carbon dioxide storage tank 14, a second condenser 15, a first control valve 16, a second control valve 17, a third control valve 18, a fourth control valve 19, and a fifth control valve 20.

[0027] Specifically, the steam inlet of the high-pressure cylinder 1 is connected to a biomass boiler, and the steam outlet is connected to a steam header. The steam header is connected to a first low-pressure cylinder 3 and a second low-pressure cylinder 5 via the first regulating valve 7 and the second regulating valve 8, respectively. A first generator 2, a second generator 4, and a third generator 6 are connected to the high-pressure cylinder 1, the first low-pressure cylinder 3, and the second low-pressure cylinder 5, respectively. A first control valve 16 is installed on the steam header between the first low-pressure cylinder 3 and the second low-pressure cylinder 5.

[0028] The first low-pressure cylinder 3 is connected to the residential heating system via the second control valve 17. The steam header is connected to the nuclear heating reactor via the third control valve 18. The nuclear heating reactor is connected to the residential heating system and to the reboiler 13 via the fourth control valve 19; the first low-pressure cylinder 3 is connected to the reboiler 13 via the fifth control valve 20; the fifth control valve 20 is connected in parallel with both the second control valve 17 and the fourth control valve 19.

[0029] The first condenser 9 is also connected to the steam header via a third regulating valve 10.

[0030] The second low-pressure cylinder 5 and the reboiler 13 are connected to the second condenser 15; the reboiler 13 is connected in sequence to the regeneration tower 12 and the absorption tower 11; the regeneration tower 12 is connected to the carbon dioxide storage tank 14.

[0031] The generator set consists of a high-pressure cylinder 1, a first generator 2, a first low-pressure cylinder 3, a second generator 4, a second low-pressure cylinder 5, and a third generator 6. High-temperature, high-pressure steam from the biomass boiler enters the high-pressure cylinder 1 to perform work, driving the first generator 2 to generate electricity. Subsequently, the steam from the high-pressure cylinder 1 is discharged into the steam header, along with surplus steam from the nuclear heating reactor. The two types of steam mix in the steam header, and the resulting low-pressure steam is sent to the low-pressure cylinders to generate electricity. The steam header is connected to the third regulating valve 10 and the first condenser 9 via an emergency bypass pipe, allowing steam to be discharged to the first condenser in emergency situations. The first regulating valve 7 controls the steam flow into the first low-pressure cylinder 3, and the second regulating valve 8 controls the steam flow into the second low-pressure cylinder 5. These regulating valves allow for separate control of the flow into the two low-pressure cylinders, enabling different steam distribution methods. Each low-pressure cylinder drives its own generator, and their operation is independent of each other.

[0032] The inlet of the main steam pipe (steam header) of the biomass boiler is connected to the gas outlet of the high-pressure cylinder 1. The outlet of the main steam pipe (steam header) is connected to the first low-pressure cylinder 3 through the first regulating valve 7, and simultaneously connected to the second low-pressure cylinder 5 through the first control valve 16. A second regulating valve 8 is also located between the second low-pressure cylinder 5 and the first control valve 16. The steam header is also connected to the emergency bypass condenser (first condenser 9). The carbon dioxide adsorbent used in the absorption tower 11 can be a chemical absorbent such as MEA.

[0033] In some embodiments, the unit's control system is divided into three parts: a data acquisition module, a core controller module, and an actuator module. The data acquisition module collects real-time nuclear steam parameters (steam temperature, pressure, flow rate, etc.), steam parameters in the steam header (steam temperature, pressure, flow rate, etc.), and parameters of each generator (power generation, speed, electrical load, etc.). The core controller module can employ control algorithms such as PID, machine learning, and artificial intelligence. Based on existing operational experience and a predictive model built using advanced algorithms, it implements control execution logic in three aspects according to the optimal requirements of heating load and economic efficiency. During steady-state operation, based on meeting the heating load and maximizing overall economic efficiency, the system optimizes the steam distribution method in the low-pressure cylinder and determines the optimal valve opening command sequence, which is then sent to the actuator module. During dynamic response, when the heating load command changes, the controller dynamically adjusts the load distribution ratio between the high-pressure and low-pressure cylinders, and between the two low-pressure cylinders, based on model predictions. For example, during a sudden load increase, the high-pressure cylinder 1 valve command is prioritized for rapid response due to its low inertia. Simultaneously, according to a preset coupling algorithm, the valve commands of the two low-pressure cylinders are coordinated to ensure that the total steam flow rate change does not exceed the reactor's following capacity limit, thus achieving a safe and rapid power transition. During safety interlocking, in special circumstances such as large load changes, steam fluctuations exceeding the regulation capacity, or any generator tripping, the controller immediately triggers, rapidly opening the third regulating valve 10 (bypass regulating valve) and sending a warning. The actuator module primarily executes controller commands through the first regulating valve 7, the second regulating valve 8, and the third regulating valve 10 to adjust the steam distribution method.

[0034] This invention relates to a nuclear-biomass coupling system, solving the problem of nuclear heating reactors being difficult to adapt to frequent changes in heating load. It accommodates surplus nuclear steam for power generation, improving the overall economic efficiency of the system and avoiding the need for frequent adjustments to the nuclear reactor due to load changes, thus ensuring the safe and stable operation of the nuclear reactor. The system features a separate-shaft design for the two low-pressure cylinders and the high-pressure cylinder, with each turbine equipped with one generator. Compared to the traditional coaxial design of high and low-pressure cylinders, each module is independent, allowing for flexible and reliable unit operation. A failure in any cylinder does not affect the operation of the remaining cylinders. The separate low-pressure cylinder design enhances the unit's peak-shaving performance, enabling adjustments to the operating mode according to heat load demand and flexibly accommodating surplus nuclear steam.

[0035] The system can capture carbon using chemical absorption in both heating and non-heating seasons. It also has high flexibility and is compatible with various types of thermal power plants and nuclear reactor coupling. Each thermal system can independently complete carbon capture and heating functions, which improves the stability and safety of system operation compared to other systems.

[0036] Carbon capture technology, particularly chemical absorption, is especially suitable for flue gas from thermal power plants (where CO2 concentrations are typically below 20%). Chemical solvents (such as amines) exhibit high selectivity for CO2 absorption. Furthermore, the load can be flexibly adjusted, responding to production demands by regulating parameters such as solvent circulation volume and regeneration temperature, achieving CO2 removal rates exceeding 90% and meeting stringent emission reduction requirements.

[0037] Based on the proposed negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system, another embodiment of the present invention also provides a control method for the negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system, comprising: During the heating season, the third control valve 18 and the fourth control valve 19 are closed. All the steam supplied by the nuclear reactor during the heating season is used for residential heating. The first regulating valve 7 is opened, the fifth control valve 20 is opened, and the second control valve 17 is closed. All the steam extracted from the first low-pressure cylinder 3 is used for the carbon capture system. The second low-pressure cylinder 5 is not started. The second regulating valve 8 is closed, the first control valve 16 is opened, and the third regulating valve 10 is opened. After the steam has finished doing its work, it enters the emergency bypass condenser.

[0038] During the heating season, the third control valve 18 and the fourth control valve 19 are closed. All the nuclear reactor heating steam is used for residential heating. However, the nuclear reactor heating steam cannot meet the heating demand. The first regulating valve 7 is opened, the fifth control valve 20 is opened, and the second control valve 17 is opened. The steam extraction part of the first low-pressure cylinder 3 is used for the carbon capture system and part is used for heating. The second low-pressure cylinder 5 is not started. The second regulating valve 8 is closed, the first control valve 16 is opened, and the third regulating valve 10 is opened. After the steam has finished doing work, it enters the emergency bypass condenser.

[0039] During the heating season, the amount of nuclear reactor steam exceeds the residential heating demand. The third control valve 18 is closed, and the fourth control valve 19 is opened. During the heating season, part of the nuclear reactor heating steam is used for residential heating, and part enters the reboiler of the carbon capture system for heat exchange. The first regulating valve 7 is opened, the fifth control valve 20 is opened, and the second control valve 17 is closed. All the steam extracted from the first low-pressure cylinder 3 is used for the carbon capture system. The second low-pressure cylinder 5 is not started. The second regulating valve 8 is closed, the first control valve 16 is opened, and the third regulating valve 10 is opened. After the steam has finished doing work, it enters the emergency bypass condenser.

[0040] During the non-heating season, the fourth control valve 19 is closed, the third control valve 18 is opened, the first regulating valve 7 is opened, and all the nuclear reactor heating steam is used for the low-pressure cylinder engine-side coupling. The fifth control valve 20 is opened, the second control valve 17 is closed, the first control valve 16 is opened, and the second regulating valve 8 is opened. All the steam extracted from the first low-pressure cylinder 3 is used for the carbon capture system. After entering the carbon capture system and completing heat exchange with the reboiler, it enters the second condenser 15.

[0041] During the heating season, when the electrical load increases during the non-heating season, the fourth control valve 19 and the third control valve 18 are opened. Part of the nuclear reactor heating steam is used for low-pressure cylinder side coupling, and part is used for the carbon capture system. The first regulating valve 7 is opened, the fifth control valve 20 is closed, the second control valve 17 is closed, the first control valve 16 is opened, and the second regulating valve 8 is opened. The biomass boiler steam is used for the turbine to do work. The nuclear reactor heating steam enters the carbon capture system to complete heat exchange with the reboiler and then enters the second condenser 15.

[0042] Example 1: This embodiment provides a control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system, including: Operating Strategy: The biomass boiler operates stably, producing 260 t / h of steam at 8.83 MPa and 535°C. This steam enters high-pressure cylinder 1 for power generation and is then used for reheat extraction. The exhaust steam flow rate of high-pressure cylinder 1 fluctuates slightly between 210 and 220 t / h. The nuclear power reactor steam output varies from 0 to 250 t / h depending on heating demand. With a nuclear power steam output of 125 t / h and a total low-pressure steam flow rate of 343.86 t / h in the steam header, operating a single low-pressure cylinder is the baseline condition. If the total low-pressure steam flow rate is lower than this, single low-pressure cylinder operation is permitted.

[0043] With a nuclear steam output of 156.25 t / h, a high-pressure cylinder exhaust of 212.12 t / h, and a total low-pressure steam flow of 368.37 t / h, two operating modes are considered. The first is single low-pressure cylinder overload operation, with steam output at 107.12% of the baseline condition. The second is dual low-pressure cylinder evenly distributed flow operation, with each low-pressure cylinder having a flow rate of 184.185 t / h, representing 53.56% of the baseline condition. Simulation calculations verify that overload operation increases the unit power by 4017 kW compared to dual low-pressure cylinder operation, a 6.47% increase. This may be due to the split-cylinder operation, which causes steam expansion and a decrease in pressure and enthalpy. However, the safety and feasibility of overload operation need to be verified.

[0044] With a nuclear steam flow rate of 187 t / h, a high-pressure cylinder exhaust flow rate of 213.12 t / h, and a total low-pressure steam flow rate of 400.12 t / h, two operating modes are considered: Mode 1 operates at full load on a single low-pressure cylinder with a steam flow rate of 343.86 t / h, while the remaining steam is fed into another low-pressure cylinder with a steam flow rate of 56.26 t / h, representing 16.36% of the baseline steam volume; Mode 2 operates with both low-pressure cylinders sharing the flow rate, with each cylinder having a flow rate of 200.06 t / h, representing 58.18% of the baseline flow rate. Calculations show that the equal flow rate sharing scheme increases power by 1446 kW compared to the non-equal flow rate sharing scheme, representing a 2.15% increase.

[0045] The nuclear steam output is 250 t / h, the high-pressure cylinder exhaust is 215.62 t / h, and the total low-pressure steam flow is 465 t / h. Two operating modes are considered: First, the flow is evenly distributed between the two low-pressure cylinders, with each cylinder producing 232.81 t / h of steam, representing 67.7% of the baseline steam output. Second, one low-pressure cylinder operates at the baseline steam output of 343.86 t / h, while the remaining 121.76 t / h is input to the other cylinder for power generation, representing 35.4% of the baseline steam output. Calculations show that the evenly distributed flow between the two cylinders results in higher power output, increasing by 2304 kW, a 3.09% improvement.

[0046] In case of an emergency, if the system power fluctuates drastically and the amount of steam changes beyond the regulation capacity, the bypass pipe is activated to discharge the steam to the condenser.

[0047] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A carbon-neutral dual-low-pressure cylinder engine-side coupled nuclear energy system, characterized in that, It includes a high-pressure cylinder and a first condenser connected to one end of the steam header, a first low-pressure cylinder and a second low-pressure cylinder connected to the steam header respectively through a first regulating valve and a second regulating valve, and a nuclear heating reactor connected to the steam header. A first control valve is installed on the steam header between the first low-pressure cylinder and the second low-pressure cylinder; the first low-pressure cylinder is connected to the residential heating system via a second control valve; the steam header is connected to the nuclear heating reactor via a third control valve; the nuclear heating reactor is connected to the residential heating system and to the reboiler via a fourth control valve; the first low-pressure cylinder is connected to the reboiler via a fifth control valve; the fifth control valve is connected in parallel with both the second and fourth control valves; the reboiler is connected to a carbon dioxide storage tank; the operating status of the first low-pressure cylinder, the second low-pressure cylinder, and the nuclear heating reactor is controlled by the first regulating valve, the second regulating valve, the first control valve, the second control valve, the third control valve, and the fourth control valve, and the operation of each valve is controlled according to different operating conditions during the heating season and non-heating season.

2. The negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system as described in claim 1, characterized in that, The high-pressure cylinder is connected to a biomass boiler at its steam inlet end and to a steam header at its steam outlet end; a first generator, a second generator, and a third generator are respectively connected to the high-pressure cylinder, the first low-pressure cylinder, and the second low-pressure cylinder.

3. The negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system as described in claim 1, characterized in that, The steam header is also connected to the first condenser via a third regulating valve.

4. The negative carbon emission dual low-pressure cylinder engine-side coupled nuclear energy system as described in claim 1, characterized in that, The second low-pressure cylinder and the reboiler are connected to a second condenser; the reboiler is sequentially connected to a regeneration tower and an absorption tower; the regeneration tower is connected to the carbon dioxide storage tank.

5. A control method for a dual-low-pressure cylinder engine-side coupled nuclear energy system with negative carbon emissions, characterized in that, The system employs a negative carbon emission dual low-pressure cylinder generator-side coupled nuclear energy system as described in any one of claims 1-4, comprising: high-temperature and high-pressure steam generated by a biomass boiler enters a high-pressure cylinder to perform work, driving a first generator to generate electricity; exhaust steam from the high-pressure cylinder enters a steam header, and surplus steam from the nuclear heating reactor enters the steam header; the two types of steam are mixed in the steam header, and the mixed low-pressure steam is transported to the low-pressure cylinder to perform work and generate electricity; the steam header is used for emergency response via a first condenser; a first regulating valve controls the steam to enter the first low-pressure cylinder, and a second regulating valve controls the steam to enter the second low-pressure cylinder.

6. The control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system as described in claim 5, characterized in that, When all the steam from the nuclear reactor is used for residential heating during the heating season, the third and fourth control valves are closed, the first and fifth regulating valves are opened, the second control valve is closed, all the steam from the first low-pressure cylinder is used for the carbon capture system, the second low-pressure cylinder is not started, the second regulating valve is closed, the first control valve is opened, the third regulating valve is opened, and after the steam has finished doing its work, it enters the first condenser.

7. The control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system as described in claim 6, characterized in that, During the heating season, all the steam supplied by the nuclear reactor is used for residential heating. However, when the steam supplied by the nuclear reactor cannot meet the heating demand, the third and fourth control valves are closed, and the first regulating valve, the fifth control valve, and the second control valve are opened. The steam extraction part of the first low-pressure cylinder is used for the carbon capture system and part is used for heating. The second low-pressure cylinder is not started, the second regulating valve is closed, and the first and third regulating valves are opened. After the steam has finished doing work, it enters the first condenser.

8. The control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system as described in claim 7, characterized in that, When the amount of nuclear reactor steam exceeds the residential heating demand during the heating season, the third control valve is closed and the fourth control valve is opened. During the heating season, part of the nuclear reactor heating steam is used for residential heating, and part enters the reboiler of the carbon capture system for heat exchange. The first regulating valve and the fifth control valve are opened, and the second control valve is closed. All the steam extracted from the first low-pressure cylinder is used for the carbon capture system. The second low-pressure cylinder is not started. The second regulating valve is closed and the first and third control valves are opened. After the steam has finished doing work, it enters the first condenser.

9. The control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system as described in claim 5, characterized in that, During the non-heating season, when all the nuclear reactor heating steam is used for low-pressure cylinder generator-side coupling, the fourth control valve is closed, and the third control valve and the first regulating valve are opened. When all the nuclear reactor heating steam is used for low-pressure cylinder generator-side coupling, the fifth control valve is opened, the second control valve is closed, and the first control valve and the second regulating valve are opened. All the steam extracted from the first low-pressure cylinder is used for the carbon capture system. After entering the carbon capture system and completing heat exchange with the reboiler, it enters the second condenser.

10. The control method for a negative carbon emission dual-low-pressure cylinder engine-side coupled nuclear energy system as described in claim 9, characterized in that, When the electricity load increases during the non-heating season, the fourth and third control valves are opened. Part of the nuclear reactor heating steam is used for low-pressure cylinder side coupling, and part is used for the carbon capture system. The first regulating valve is opened, and the fifth and second control valves are closed. The first control valve and the second regulating valve are opened. The biomass boiler steam is used for the turbine to do work. The nuclear reactor heating steam enters the carbon capture system to complete the heat exchange with the reboiler and then enters the second condenser.

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