Steam turbine low-pressure cylinder cutting heat supply unit coupled with carbon capture device

Abstract

The utility model relates to a steam turbine low-pressure cylinder cutting heat supply unit coupled with a carbon capture device, which adopts the technical scheme that heat supply steam is taken from a communicating pipe of a medium-pressure cylinder and a low-pressure cylinder, a steam extraction pipeline is divided into two branches, and steam of the first branch is connected to a drain pipeline through a second heat supply network heater and a capture device reboiler; steam of the second branch is connected to a drainage pipeline through a third heating network heater, a drainage cooler is installed on the drainage pipeline, and the tail end of the drainage pipeline is connected with the outlet end of the condenser; a carbon capture device reboiler is connected with a desorption tower through a pipeline, and the top of the desorption tower is connected with a first heating network heater and a desorption tower top condenser through pipelines and then connected to a carbon dioxide compressor and a carbon dioxide cooler. The system has the beneficial effects that the system can operate in three modes of real-time power generation, heat supply and carbon capture; waste heat in the carbon capture device is recovered, so that the temperature of condensed water is obviously increased, and the utilization rate of heat and the efficiency of a unit are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of heating units and carbon capture technology for coal-fired flue gas, and particularly to a steam turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device. Background Technology

[0002] In oilfield production, self-contained power plants play a vital role in ensuring energy supply. In the current environment, retrofitting coal-fired units with carbon capture technology is of great significance for reducing anthropogenic carbon dioxide emissions. Chemical absorption methods using amines as absorbents are relatively mature, but they are prone to decomposition at high temperatures, thus requiring strict control over the pressure and temperature of the carbon capture steam. This leads to a mismatch in steam energy levels, resulting in energy waste. Furthermore, waste heat loss is unavoidable during the operation of the carbon capture unit.

[0003] In addition, coal-fired power plants are the main source of heating in northern China during winter, which places higher demands on the steam extraction capacity of the turbine system. In response, most units have undergone low-pressure cylinder zero-output modification, which has resulted in excessively low condensate temperature and affected the thermal economy of the units.

[0004] Chinese patent application number CN202211692472.9, entitled "A Steam Turbine System with Freely Combinable Exhaust Steam Heating," describes a steam turbine system capable of flexibly utilizing exhaust steam for heating. It can switch between three operating conditions: high back pressure heating, mid-exhaust steam extraction heating, and low-pressure cylinder zero-output heating. This invention effectively addresses the varying heating demands at the beginning, middle, and end of the season, allowing for flexible combinations with the exhaust steam heating system. Specifically, it utilizes three subsystems: high back pressure heating, mid-exhaust steam extraction heating, and low-pressure cylinder zero-output heating. These subsystems can operate independently, in combination with any two, or simultaneously, depending on the heating demand (Q). This flexible switching optimizes the unit's operating mode under different demands, thereby maximizing energy utilization.

[0005] Chinese patent application number CN202410574071.6, entitled "Optimal Dispatch Method for Power Systems Considering Electrothermal Coupling and Improved Operational Flexibility of Carbon Capture Power Plants," describes a power system comprising a carbon capture thermal power system, a renewable energy system, electric boilers, and thermal storage devices. The carbon capture thermal power system features a low-pressure cylinder zero-output modification structure and a parallel extraction steam structure formed by a small back-pressure turbine and a pressure-reducing valve. The optimal dispatch method includes constructing and solving an optimal dispatch model, outputting the optimal dispatch decision. The optimal dispatch model includes an objective function and constraints, including power conservation constraints, steam conservation constraints, and electrothermal coupling constraints. The electrothermal coupling constraint indicates that the total power of the carbon capture thermal power plant and the steam consumption from carbon capture desorption lie within the electrothermal feasible region. This dispatch method accurately reflects the electrothermal coupling relationship of carbon capture to improve dispatch feasibility, and the two structural designs for auxiliary equipment and carbon capture thermal power plants enhance the flexibility of power system dispatch.

[0006] Chinese patent application number CN201510190754.2, entitled "A Carbon Dioxide Capture and Regeneration System Integrated with the Steam-Water System of a Power Unit," describes a system where the steam outlet from the intermediate-pressure cylinder of a steam turbine is split into two paths: one connected to the inlet of the low-pressure cylinder, and the other connected to the inlet of the small turbine driving the CO2 compressor. The outlet of the small turbine is connected to the inlet of the boiler feedwater heater. The steam outlet of the heater is also split into two paths: one connected to the inlet of the reboiler of the regeneration tower solution, and the other connected to the inlet of the lower-temperature boiler feedwater heater. The exhaust steam from the intermediate-pressure cylinder is also split into two paths: one directly enters the low-pressure cylinder to perform work, and the other is sent to the small turbine driving the CO2 compressor, directly providing power instead of an electric motor. Because the exhaust steam from the intermediate-pressure cylinder has lower quality and lower power generation efficiency, directly powering the CO2 compressor reduces intermediate steps and indirectly reduces energy consumption. This invention also reduces the thermal degradation loss of the carbon dioxide capture and absorption solution, thus reducing the system's operating costs. Utility Model Content

[0007] The purpose of this invention is to address the aforementioned deficiencies in the existing technology by providing a steam turbine low-pressure cylinder cut-off heating unit coupled with a carbon capture device. Under the premise of meeting the carbon capture capacity and external heat load, the carbon capture device is thermally integrated with the heating system of the cogeneration plant. The heating system is used to regulate the temperature of the carbon capture steam and recover waste heat from the carbon capture process to heat the condensate of the unit, thereby improving the economic efficiency of the cogeneration unit operation.

[0008] The present invention relates to a turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device. The technical solution includes: a turbine intermediate-pressure cylinder (1), a turbine low-pressure cylinder (2), a generator (3), a condenser (4), an intermediate-low pressure cylinder connecting pipe (5), a heating network return water pipe (7), and a heating network supply water pipe (17). It also includes an extraction steam pipe (6), a No. 1 heating network heater (8), a No. 2 heating network heater (9), a No. 3 heating network heater (10), a carbon capture device reboiler (11), a desorption tower top condenser (12), a carbon dioxide compressor (13), and a carbon dioxide cooling system. The equipment includes a steam generator (14), a condensate cooler (15), a condensate pipe (16), and a desorption tower (18). The heating steam is taken from the medium and low pressure cylinder connecting pipe (5) through the extraction steam pipe (6). The extraction steam pipe (6) is divided into two branches. The steam of the first branch is connected to the condensate pipe (16) through the second heat network heater (9) and the capture device reboiler (11). The steam of the second branch is connected to the condensate pipe (16) through the third heat network heater (10). A condensate cooler (15) is installed on the condensate pipe (16), and the end of the condensate pipe (16) is connected to the outlet end of the condenser (4).

[0009] The carbon capture device reboiler (11) is connected to the desorption tower (18) via a pipeline. The top of the desorption tower (18) is connected to the No. 1 heat network heater (8) and the top condenser (12) of the desorption tower via a pipeline, and then connected to a set of more than one carbon dioxide compressor (13) and carbon dioxide cooler (14).

[0010] Preferably, the heat network return water pipe (7) is divided into two branches. The first branch is connected to the heat network supply water pipe (17) through the first heat network heater (8) and the second heat network heater (9) in sequence. The second branch is connected to the heat network supply water pipe (17) after being mixed with the first branch through the third heat network heater (10).

[0011] Preferably, the first branch of the above-mentioned heat network return water pipe (7) is connected to the inlet of the first heat network heater (8) via a pipeline, the outlet of the first heat network heater (8) is connected to the inlet of the second heat network heater (9) via a pipeline, and the outlet of the second heat network heater (9) is connected to the heat network supply water pipe (17) via a pipeline.

[0012] Preferably, the second branch of the above-mentioned heat network return water pipe (7) is connected to the pipe inlet of the No. 3 heat network heater (10) through a pipeline, and the pipe outlet of the No. 3 heat network heater (10) is collected to the heat network supply water pipe (17) through a pipeline.

[0013] Preferably, the first branch of the above-mentioned extraction steam pipe (6) is connected to the shell-side inlet of the No. 2 heat network heater (9) via a pipeline, the shell-side outlet of the No. 2 heat network heater (9) is connected to the tube-side inlet of the carbon capture device reboiler (11) via a pipeline, and the tube-side outlet of the carbon capture device reboiler (11) is connected to the drain pipe (16) via a pipeline.

[0014] Preferably, the second branch of the above-mentioned extraction steam pipe (6) is connected to the shell-side inlet of the No. 3 heat network heater (10) via a pipeline, and the shell-side outlet of the No. 3 heat network heater (10) is connected to the drain pipe (16) via a pipeline.

[0015] Preferably, the shell-side inlet of the reboiler (11) of the carbon capture device is connected to the bottom of the desorption tower (18) via a pipeline, and the shell-side outlet of the reboiler (11) of the carbon capture device is connected to the middle and lower side line of the desorption tower (18) via a pipeline.

[0016] Preferably, the top of the above-mentioned desorption tower (18) is connected to the shell-side inlet of the No. 1 heat network heater (8) via a pipeline, and the shell-side outlet of the No. 1 heat network heater (8) is connected to the carbon dioxide buffer tank (21) via a pipeline and the top condenser (12) of the desorption tower.

[0017] Preferably, the lower end of the carbon dioxide buffer tank (21) is connected to the upper side of the desorption tower (18) via a pipeline, and the top of the carbon dioxide buffer tank (21) is connected to a group of more than one carbon dioxide compressor (13) and carbon dioxide cooler (14) via a pipeline.

[0018] Preferably, the carbon dioxide compressor (13) and carbon dioxide cooler (14) described above are provided in three sets.

[0019] The beneficial effects of this utility model are:

[0020] (1) Compared with conventional condensing generator sets and cogeneration units, this utility model can realize the operation of three modes: real-time power generation, heating and carbon capture.

[0021] (2) Since the absorbent of the carbon capture device is easily corroded and degraded at high temperatures, the temperature of the carbon capture steam is adjusted by the heating system to meet the requirements of the reboiler and avoid the waste of heat.

[0022] (3) In view of the problem that the low-pressure heater cannot heat the condensate of the unit under the low-pressure cylinder cut-off operation condition of the steam turbine, the waste heat in the carbon capture device of this utility model is recovered, which significantly increases the temperature of the condensate and greatly improves the heat utilization rate and the efficiency of the unit. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating Embodiment 1 of the present invention;

[0024] Figure 2 This is a flowchart illustrating Embodiment 3 of this utility model;

[0025] Figure 3 This is a flowchart illustrating existing technology;

[0026] In the diagram above: 1. Intermediate-pressure cylinder of steam turbine; 2. Low-pressure cylinder of steam turbine; 3. Generator; 4. Condenser; 5. Connecting pipe between intermediate and low-pressure cylinders; 6. Extraction steam pipe; 7. Heater network return water pipe; 8. Heater network 1; 9. Heater network 2; 10. Heater network 3; 11. Reboiler of carbon capture device; 12. Condenser at the top of desorption tower; 13. Carbon dioxide compressor; 14. Carbon dioxide cooler; 15. Drain cooler; 16. Drain pipe; 17. Heater network supply water pipe; 18. Desorption tower; 19. Deaerator; 20. Low-pressure heater; 21. Carbon dioxide buffer tank. Detailed Implementation

[0027] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0028] Example 1, referring to Figure 1 The present invention relates to a turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device, comprising a turbine intermediate-pressure cylinder 1, a turbine low-pressure cylinder 2, a generator 3, a condenser 4, an intermediate-low pressure cylinder connecting pipe 5, a heating network return water pipe 7, and a heating network supply water pipe 17. The reheat steam of the unit enters the turbine intermediate-pressure cylinder 1 to drive the blades to do work, and then enters the turbine low-pressure cylinder 2 through the intermediate-low pressure cylinder connecting pipe 5. The exhaust gas of the turbine low-pressure cylinder 2 enters the condenser 4 and is condensed into condensate.

[0029] The system also includes a steam extraction pipe 6, a No. 1 heating network heater 8, a No. 2 heating network heater 9, a No. 3 heating network heater 10, a carbon capture device reboiler 11, a desorption tower top condenser 12, a carbon dioxide compressor 13, a carbon dioxide cooler 14, a condensate cooler 15, a condensate pipe 16, and a desorption tower 18. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5 through the steam extraction pipe 6. The steam extraction pipe 6 is divided into two branches. The steam of the first branch is connected to the condensate pipe 16 through the No. 2 heating network heater 9 and the capture device reboiler 11. The steam of the second branch is connected to the condensate pipe 16 through the No. 3 heating network heater 10. A condensate cooler 15 is installed on the condensate pipe 16, and the end of the condensate pipe 16 is connected to the outlet end of the condenser 4.

[0030] The carbon capture device reboiler 11 is connected to the desorption tower 18 via a pipeline. The top of the desorption tower 18 is connected to the No. 1 heat network heater 8 and the top condenser 12 of the desorption tower via a pipeline, and then connected to one or more sets of carbon dioxide compressors 13 and carbon dioxide coolers 14.

[0031] Preferably, the heat network return water pipe 7 is divided into two branches. The first branch is connected to the heat network supply water pipe 17 through the first heat network heater 8 and the second heat network heater 9 in sequence. The second branch is connected to the heat network supply water pipe 17 after being mixed with the first branch through the third heat network heater 10.

[0032] Preferably, the first branch of the aforementioned heat network return water pipe 7 is connected to the inlet of the first heat network heater 8 via a pipeline, the outlet of the first heat network heater 8 is connected to the inlet of the second heat network heater 9 via a pipeline, and the outlet of the second heat network heater 9 is connected to the heat network supply water pipe 17 via a pipeline.

[0033] Preferably, the second branch of the aforementioned heat network return water pipe 7 is connected to the inlet of the third heat network heater 10 via a pipeline, and the outlet of the third heat network heater 10 is collected into the heat network supply water pipe 17 via a pipeline.

[0034] Preferably, the first branch of the extraction steam pipe 6 is connected to the shell-side inlet of the second heating network heater 9 via a pipeline, the shell-side outlet of the second heating network heater 9 is connected to the tube-side inlet of the carbon capture device reboiler 11 via a pipeline, and the tube-side outlet of the carbon capture device reboiler 11 is connected to the drain pipe 16 via a pipeline.

[0035] Preferably, the second branch of the aforementioned extraction steam pipe 6 is connected to the shell-side inlet of the No. 3 heating network heater 10 via a pipeline, and the shell-side outlet of the No. 3 heating network heater 10 is connected to the drain pipe 16 via a pipeline.

[0036] Preferably, the shell-side inlet of the reboiler 11 of the carbon capture device is connected to the bottom of the desorption tower 18 via a pipeline, and the shell-side outlet of the reboiler 11 of the carbon capture device is connected to the middle and lower side line of the desorption tower 18 via a pipeline.

[0037] Preferably, the top of the desorption tower 18 is connected to the shell-side inlet of the No. 1 heat network heater 8 via a pipeline, and the shell-side outlet of the No. 1 heat network heater 8 is connected to the carbon dioxide buffer tank 21 via a pipeline and the top condenser 12 of the desorption tower.

[0038] Preferably, the lower end of the aforementioned carbon dioxide buffer tank 21 is connected to the upper side of the desorption tower 18 via a pipeline, and the top of the carbon dioxide buffer tank 21 is connected to one or more carbon dioxide compressors 13 and carbon dioxide coolers 14 via a pipeline.

[0039] This invention is used in the drainage of heating networks:

[0040] The return water of the heating network is divided into two branches. The first branch enters the cold side of the No. 1 heating network heater 8 to absorb heat and then enters the No. 2 heating network heater 9 to continue absorbing heat and increasing its temperature. The second branch enters the cold side of the No. 3 heating network heater 10 to absorb heat and then mixes with the first branch to form the heating network water supply. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5. The extraction steam pipe 6 is divided into two branches. The steam in the first branch is regulated by pressure and enters the hot side of the No. 2 heating network heater 9 to be reduced to saturated steam state. Before entering the condensate pipe 16, it releases condensation heat in the reboiler 11 of the trapping device to provide heat for the carbon dioxide desorption process. The steam in the second branch enters the hot side of the No. 3 heating network heater 10 to release heat and then enters the condensate pipe 16. After being cooled by the condensate cooler 15, it mixes with the condensate at the outlet of the condenser 4.

[0041] On the desorption side of the carbon capture device, the heat required for carbon dioxide desorption is provided by the reboiler 11. The regeneration gas from the desorption tower 18 is discharged from the top of the tower, flows through the hot side of the first heat network heater 8 and the desorption tower top condenser 12, and obtains high-purity carbon dioxide gas. For convenient transportation and storage, the carbon dioxide is compressed to a supercritical state by a three-stage compressor 13, and a carbon dioxide cooler 14 is provided at the outlet of each stage compressor.

[0042] Example 2: The turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device mentioned in this utility model includes a turbine intermediate-pressure cylinder 1, a turbine low-pressure cylinder 2, a generator 3, a condenser 4, an intermediate-low pressure cylinder connecting pipe 5, a heating network return water pipe 7, and a heating network supply water pipe 17. The reheat steam of the unit enters the turbine intermediate-pressure cylinder 1 to drive the blades to do work, and then enters the turbine low-pressure cylinder 2 through the intermediate-low pressure cylinder connecting pipe 5. The exhaust gas of the turbine low-pressure cylinder 2 enters the condenser 4 and is condensed into condensate.

[0043] The system also includes a steam extraction pipe 6, a No. 1 heating network heater 8, a No. 2 heating network heater 9, a No. 3 heating network heater 10, a carbon capture device reboiler 11, a desorption tower top condenser 12, a carbon dioxide compressor 13, a carbon dioxide cooler 14, a condensate cooler 15, a condensate pipe 16, and a desorption tower 18. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5 through the steam extraction pipe 6. The steam extraction pipe 6 is divided into two branches. The steam of the first branch is connected to the condensate pipe 16 through the No. 2 heating network heater 9 and the capture device reboiler 11. The steam of the second branch is connected to the condensate pipe 16 through the No. 3 heating network heater 10. A condensate cooler 15 is installed on the condensate pipe 16, and the end of the condensate pipe 16 is connected to the outlet end of the condenser 4.

[0044] The carbon capture device reboiler 11 is connected to the desorption tower 18 via a pipeline. The top of the desorption tower 18 is connected to the No. 1 heat network heater 8 and the top condenser 12 of the desorption tower via a pipeline, and then connected to one or more sets of carbon dioxide compressors 13 and carbon dioxide coolers 14.

[0045] The difference from Example 1 is:

[0046] In this embodiment, there are three sets of carbon dioxide compressors 13 and carbon dioxide coolers 14. The top of the carbon dioxide buffer tank 21 is connected to the first set of carbon dioxide compressors 13 through a pipeline, and then connected to the carbon dioxide cooler 14 through a pipeline. Then, it is connected to the second set of carbon dioxide compressors 13 through a pipeline, and then connected to the carbon dioxide cooler 14 through the third set of carbon dioxide compressors 13 through a pipeline. The carbon dioxide is compressed to a supercritical state by the three-stage compressors 13, which facilitates transportation and storage.

[0047] Example 3: The turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device mentioned in this utility model includes a turbine intermediate-pressure cylinder 1, a turbine low-pressure cylinder 2, a generator 3, a condenser 4, an intermediate-low pressure cylinder connecting pipe 5, a heating network return water pipe 7, and a heating network supply water pipe 17. The reheat steam of the unit enters the turbine intermediate-pressure cylinder 1 to drive the blades to do work, and then enters the turbine low-pressure cylinder 2 through the intermediate-low pressure cylinder connecting pipe 5. The exhaust gas of the turbine low-pressure cylinder 2 enters the condenser 4 and is condensed into condensate.

[0048] The system also includes a steam extraction pipe 6, a No. 1 heating network heater 8, a No. 2 heating network heater 9, a No. 3 heating network heater 10, a carbon capture device reboiler 11, a desorption tower top condenser 12, a carbon dioxide compressor 13, a carbon dioxide cooler 14, a condensate cooler 15, a condensate pipe 16, and a desorption tower 18. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5 through the steam extraction pipe 6. The steam extraction pipe 6 is divided into two branches. The steam of the first branch is connected to the condensate pipe 16 through the No. 2 heating network heater 9 and the capture device reboiler 11. The steam of the second branch is connected to the condensate pipe 16 through the No. 3 heating network heater 10. A condensate cooler 15 is installed on the condensate pipe 16, and the end of the condensate pipe 16 is connected to the outlet end of the condenser 4.

[0049] The carbon capture device reboiler 11 is connected to the desorption tower 18 via a pipeline. The top of the desorption tower 18 is connected to the No. 1 heat network heater 8 and the top condenser 12 of the desorption tower via a pipeline, and then connected to one or more sets of carbon dioxide compressors 13 and carbon dioxide coolers 14.

[0050] The difference from Example 2 is:

[0051] Reference Figure 2 To better achieve low-temperature reheating of condensate, the process flow has been adjusted as follows:

[0052] Under the operating condition of cylinder cut-off of the low-pressure cylinder 2 of the steam turbine, the original low-pressure heater 20 is cancelled. The condensate and condensate are mixed and divided into three streams, which flow through the cold side of the carbon dioxide cooler 14 to recover the waste heat of the carbon dioxide compression process. They are connected to the cold side of the condensate cooler 15 and the desorption tower top condenser 12 respectively, and the condensate temperature is further increased.

[0053] Example 4: The turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device mentioned in this utility model includes a turbine intermediate-pressure cylinder 1, a turbine low-pressure cylinder 2, a generator 3, a condenser 4, an intermediate-low pressure cylinder connecting pipe 5, a heating network return water pipe 7, and a heating network supply water pipe 17. The reheat steam of the unit enters the turbine intermediate-pressure cylinder 1 to drive the blades to do work, and then enters the turbine low-pressure cylinder 2 through the intermediate-low pressure cylinder connecting pipe 5. The exhaust gas of the turbine low-pressure cylinder 2 enters the condenser 4 and is condensed into condensate.

[0054] The system also includes a steam extraction pipe 6, a No. 1 heating network heater 8, a No. 2 heating network heater 9, a No. 3 heating network heater 10, a carbon capture device reboiler 11, a desorption tower top condenser 12, a carbon dioxide compressor 13, a carbon dioxide cooler 14, a condensate cooler 15, a condensate pipe 16, and a desorption tower 18. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5 through the steam extraction pipe 6. The steam extraction pipe 6 is divided into two branches. The steam of the first branch is connected to the condensate pipe 16 through the No. 2 heating network heater 9 and the capture device reboiler 11. The steam of the second branch is connected to the condensate pipe 16 through the No. 3 heating network heater 10. A condensate cooler 15 is installed on the condensate pipe 16, and the end of the condensate pipe 16 is connected to the outlet end of the condenser 4.

[0055] The carbon capture device reboiler 11 is connected to the desorption tower 18 via a pipeline. The top of the desorption tower 18 is connected to the No. 1 heat network heater 8 and the top condenser 12 of the desorption tower via a pipeline, and then connected to one or more sets of carbon dioxide compressors 13 and carbon dioxide coolers 14.

[0056] The difference from Example 3 is:

[0057] A deaerator 19 is connected to the output end of the condensate cooler 15 and the desorption tower top condenser 12. The preheated condensate enters the deaerator 19 to remove oxygen and other non-condensable gases from the boiler feedwater, ensuring the quality of the feedwater, preventing corrosion of thermal equipment, and ensuring the safe operation of the power plant.

[0058] Example 5: The turbine low-pressure cylinder cut-off heating unit with a coupled carbon capture device mentioned in this utility model includes a turbine intermediate-pressure cylinder 1, a turbine low-pressure cylinder 2, a generator 3, a condenser 4, an intermediate-low pressure cylinder connecting pipe 5, a heating network return water pipe 7, and a heating network supply water pipe 17. The reheat steam of the unit enters the turbine intermediate-pressure cylinder 1 to drive the blades to do work, and then enters the turbine low-pressure cylinder 2 through the intermediate-low pressure cylinder connecting pipe 5. The exhaust gas of the turbine low-pressure cylinder 2 enters the condenser 4 and is condensed into condensate.

[0059] The system also includes a steam extraction pipe 6, a No. 1 heating network heater 8, a No. 2 heating network heater 9, a No. 3 heating network heater 10, a carbon capture device reboiler 11, a desorption tower top condenser 12, a carbon dioxide compressor 13, a carbon dioxide cooler 14, a condensate cooler 15, a condensate pipe 16, and a desorption tower 18. The heating steam is taken from the medium and low pressure cylinder connecting pipe 5 through the steam extraction pipe 6. The steam extraction pipe 6 is divided into two branches. The steam of the first branch is connected to the condensate pipe 16 through the No. 2 heating network heater 9 and the capture device reboiler 11. The steam of the second branch is connected to the condensate pipe 16 through the No. 3 heating network heater 10. A condensate cooler 15 is installed on the condensate pipe 16, and the end of the condensate pipe 16 is connected to the outlet end of the condenser 4.

[0060] The carbon capture device reboiler 11 is connected to the desorption tower 18 via a pipeline. The top of the desorption tower 18 is connected to the No. 1 heat network heater 8 and the top condenser 12 of the desorption tower via a pipeline, and then connected to one or more sets of carbon dioxide compressors 13 and carbon dioxide coolers 14.

[0061] The difference from Example 1 is:

[0062] Based on actual heating needs, a third branch can be added to the steam extraction pipeline 6, and a set of heat network heaters can be added on the third branch for backup, thereby providing a more stable heating service for northern winters.

[0063] The above description is merely a preferred embodiment of this utility model. Any person skilled in the art may modify this utility model or modify it into an equivalent technical solution using the technical solutions described above. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of this utility model are within the scope of protection claimed by this utility model.

Claims

1. A turbine low-pressure cylinder cut-off heating unit with coupled carbon capture device, comprising a turbine intermediate-pressure cylinder (1), a turbine low-pressure cylinder (2), a generator (3), a condenser (4), an intermediate-low pressure cylinder connecting pipe (5), a heating network return water pipe (7), and a heating network supply water pipe (17), characterized in that: It also includes a steam extraction pipe (6), a No. 1 heat network heater (8), a No. 2 heat network heater (9), a No. 3 heat network heater (10), a carbon capture device reboiler (11), a desorption tower top condenser (12), a carbon dioxide compressor (13), a carbon dioxide cooler (14), a condensate cooler (15), a condensate pipe (16), and a desorption tower (18). The heating steam is taken from the medium and low pressure cylinder connecting pipe (5) through the steam extraction pipe (6). The steam extraction pipe (6) is divided into two branches. The steam of the first branch is connected to the condensate pipe (16) through the No. 2 heat network heater (9) and the capture device reboiler (11). The steam of the second branch is connected to the condensate pipe (16) through the No. 3 heat network heater (10). A condensate cooler (15) is installed on the condensate pipe (16), and the end of the condensate pipe (16) is connected to the outlet end of the condenser (4). The carbon capture device reboiler (11) is connected to the desorption tower (18) via a pipeline. The top of the desorption tower (18) is connected to the No. 1 heat network heater (8) and the top condenser (12) of the desorption tower via a pipeline, and then connected to a set of more than one carbon dioxide compressor (13) and carbon dioxide cooler (14).

2. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 1, characterized in that: The return water pipe (7) of the heating network is divided into two branches. The first branch is connected to the heating network supply water pipe (17) through the No. 1 heating network heater (8) and the No. 2 heating network heater (9) in sequence. The second branch is connected to the heating network supply water pipe (17) after mixing with the first branch through the No. 3 heating network heater (10).

3. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 2, characterized in that: The first branch of the heat network return water pipe (7) is connected to the inlet of the first heat network heater (8) via a pipeline. The outlet of the first heat network heater (8) is connected to the inlet of the second heat network heater (9) via a pipeline. The outlet of the second heat network heater (9) is connected to the heat network supply water pipe (17) via a pipeline.

4. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 3, characterized in that: The second branch of the heat network return water pipe (7) is connected to the inlet of the No. 3 heat network heater (10) via a pipeline, and the outlet of the No. 3 heat network heater (10) is collected to the heat network supply water pipe (17) via a pipeline.

5. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 4, characterized in that: The first branch of the extraction steam pipe (6) is connected to the shell-side inlet of the No. 2 heat network heater (9) via a pipeline. The shell-side outlet of the No. 2 heat network heater (9) is connected to the tube-side inlet of the carbon capture device reboiler (11) via a pipeline. The tube-side outlet of the carbon capture device reboiler (11) is connected to the drain pipe (16) via a pipeline.

6. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 5, characterized in that: The second branch of the extraction steam pipe (6) is connected to the shell-side inlet of the No. 3 heating network heater (10) via a pipeline, and the shell-side outlet of the No. 3 heating network heater (10) is connected to the drain pipe (16) via a pipeline.

7. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 1, characterized in that: The shell-side inlet of the reboiler (11) of the carbon capture device is connected to the bottom of the desorption tower (18) via a pipeline, and the shell-side outlet of the reboiler (11) of the carbon capture device is connected to the middle and lower side line of the desorption tower (18) via a pipeline.

8. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 7, characterized in that: The top of the desorption tower (18) is connected to the shell-side inlet of the No. 1 heat network heater (8) via a pipeline, and the shell-side outlet of the No. 1 heat network heater (8) is connected to the carbon dioxide buffer tank (21) via a pipeline and the top condenser (12) of the desorption tower.

9. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 8, characterized in that: The lower end of the carbon dioxide buffer tank (21) is connected to the upper side of the desorption tower (18) via a pipeline, and the top of the carbon dioxide buffer tank (21) is connected to a group of more than one carbon dioxide compressor (13) and carbon dioxide cooler (14) via a pipeline.

10. The turbine low-pressure cylinder cut-off heating unit with the coupled carbon capture device according to claim 9, characterized in that: The carbon dioxide compressor (13) and carbon dioxide cooler (14) are provided in three sets.

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