Nuclear power plant industrial steam condensate backwater system and control method

Abstract

The present application relates to the field of control, especially to a nuclear power plant industrial steam condensate backwater system and control method. The system comprises a first condensate main pipe, the rear end of which is connected to a first unit condensate main pipeline and a first unit condenser through two branches; a second condensate main pipe, the rear end of which is connected to a second unit condensate main pipeline and a second unit condenser through two branches; two first-stage feedwater preheating systems, the rear ends of which are connected to the front end of the first condensate main pipe through condensate pipelines, to transport the condensate after heat exchange of collected steam conversion equipment to the condensate main pipe; two first-stage feedwater preheating systems, the rear ends of which are connected to the front end of the second condensate main pipe through condensate pipelines, to transport the condensate after heat exchange of collected steam conversion equipment to the condensate main pipe; a plurality of flow meters are arranged in parallel on each condensate main pipe. When the unit is normally operated, the condensate after heat exchange of steam conversion equipment flows back to the main condensate pipeline of the unit through the condensate main pipe; when the unit is started, the condensate after heat exchange of steam conversion equipment flows to the condenser through the condensate main pipe. The present application ensures the reuse of condensate and the safety and stability of the two-back condensate system.

Description

Technical Field

[0001] This invention relates to the field of control, and more particularly to a nuclear power plant industrial steam condensate return system and control method. Background Technology

[0002] In nuclear power plants, the main steam in the secondary loop is used for steam power generation after heat exchange in the steam conversion equipment. However, the condensate after heat exchange cannot be collected, resulting in energy loss.

[0003] Currently, condensate recovery is an important energy-saving measure in steam heating systems. However, in the field of nuclear energy utilization, there is no precedent to draw upon for using secondary loop steam from nuclear power plants as a heat source to produce industrial steam.

[0004] The main challenge is to achieve condensate recovery while ensuring the safety and stability of the secondary condensate system and avoiding the mixing of media from different units. There is currently no precedent for this in the field of comprehensive nuclear energy utilization. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a nuclear power plant industrial steam condensate return system and control method, which ensures the reuse of condensate and at the same time ensures the safety and stability of the secondary condensate return system.

[0006] This invention provides a nuclear power plant industrial steam condensate return system, comprising:

[0007] The first condensate main pipe is connected to the first unit's condensate main pipe and the first unit's condenser via two branch lines at the rear end.

[0008] The second condensate main pipe is connected to the second unit's condensate main pipe and the second unit's condenser via two branch lines at the rear end.

[0009] Two primary feedwater preheating systems are connected to the front end of the first condensate header via condensate pipes at their rear ends, transporting the collected condensate from the steam conversion equipment to the condensate header.

[0010] Two primary feedwater preheating systems are connected to the front end of the second condensate header via condensate pipes at their rear ends, transporting the collected condensate from the steam conversion equipment to the condensate header.

[0011] Multiple flow meters are connected in parallel on each condensate tap.

[0012] An isolation valve for supplying the main condensate pipeline of the first unit is installed on the branch line connected to the main condensate pipeline of the first unit; an isolation valve for supplying the condenser of the first unit is installed on the branch line connected to the condenser of the first unit.

[0013] An isolation valve for supplying the main condensate pipeline of the second unit to the second unit is installed on the branch connecting the main condensate pipeline of the second unit; an isolation valve for supplying the condenser of the second unit to the second unit is installed on the branch connecting the condenser of the second unit.

[0014] In one specific embodiment of the present invention, two primary water preheating systems are respectively connected to the front end of the first condensate header via the condensate pipes of the first unit and the second unit.

[0015] The other two primary water supply preheating systems are connected to the front end of the second condensate header via the condensate pipes of the first unit and the second unit, respectively.

[0016] Each first unit's condensate pipeline is equipped with a first electric isolation valve; each second unit's condensate pipeline is equipped with a second electric isolation valve.

[0017] In one specific embodiment of the present invention, a temperature measuring device and a pressure measuring device are provided on the first condensate mother tube.

[0018] The second condensate header is equipped with a temperature measuring device and a pressure measuring device.

[0019] In one specific embodiment of the present invention, there are at least three flow meters.

[0020] This invention provides a method for controlling the return water of industrial steam supply condensate in nuclear power plants, comprising:

[0021] During normal operation of the unit, the condensate after heat exchange in the steam conversion equipment flows back to the main condensate pipeline of the unit through the condensate header.

[0022] During unit startup, the condensate after heat exchange in the steam conversion equipment flows to the condenser through the condensate header.

[0023] In one specific embodiment of the present invention, during normal operation of the unit,

[0024] The isolation valves of the main condensate pipeline of Unit 1 and Unit 2 are opened, while the isolation valves for the condenser of Unit 1 and Unit 2 are closed.

[0025] When the electric isolation valve of the main steam pipeline system of the first unit is fully open or fully closed, it will open or close the electric isolation valve on the condensate pipeline of the first unit in conjunction with the valve position, and at the same time close or open the electric isolation valve on the condensate pipeline of the second unit.

[0026] When the electric isolation valve of the main steam pipeline system of the second unit is fully open or fully closed, it will open or close the electric isolation valve on the condensate pipeline of the second unit in conjunction with the first unit.

[0027] In a specific embodiment of the present invention, under the unit startup condition, the isolation valves of the main condensate pipeline of the first unit and the main condensate pipeline of the second unit are closed, while the isolation valves of the condenser to the first unit and the condenser to the second unit are opened, so that the condensate flows to the condenser through the condensate header.

[0028] In one specific embodiment of the present invention, it further includes:

[0029] When the liquid level observed in the evaporator is high, the isolation valve for the condenser of the first unit and the isolation valve for the condenser of the second unit will be opened automatically.

[0030] When the deaerator on the conventional island is at a high water level, the isolation valve for the condenser of the first unit and the isolation valve for the condenser of the second unit will be opened automatically.

[0031] Compared with the prior art, the nuclear power plant industrial steam condensate return system and control method of the present invention have the following beneficial effects:

[0032] (1) The condensate from the steam heating of both nuclear power units is recovered simultaneously through the condensate recovery system. This ensures the safety and stability of the secondary loop condensate system while achieving energy conservation, emission reduction, and improved economic efficiency.

[0033] (2) Through clever control logic design, the condensate of the main steam after heat exchange in the steam conversion equipment is diverted to different secondary loop equipment when the nuclear power unit is under different operating conditions.

[0034] (3) Automatic control of condensate return water, interlock control of condensate return water isolation valve to avoid mixing of secondary circuit media of two units.

[0035] (4) The interlocking of the condensate return water control system for industrial steam supply in nuclear power plants effectively reduces the risk of human error.

[0036] (5) The measurement of condensate return flow rate is carried out through a three-out-of-two calculation logic to ensure the reliability of the return flow rate in subsequent logic operations. Attached Figure Description

[0037] Figure 1 A schematic diagram showing the structure of the industrial steam supply condensate return system in a nuclear power plant.

[0038] In the diagram, 1-First-stage feedwater preheating system (NAB); 2-Second-stage feedwater preheating system (NAB); 3-Third-stage feedwater preheating system (NAB); 4-Fourth-stage feedwater preheating system (NAB); 5-Condensate isolation valve A of the first unit; 6-Condensate isolation valve A of the second unit; 7-Condensate isolation valve B of the second unit; 8-Condensate isolation valve B of the first unit; 9-Condensate isolation valve C of the second unit; 10-Condensate isolation valve C of the first unit; 11-Condensate isolation valve D of the first unit; 12-Condensate isolation valve D of the second unit; 13-Condensate main pipe thermometer A; 14-Condensate main pipe pressure gauge A; 15-Condensate main pipe thermometer B ; 16-Condensate main pipe pressure gauge B; 17-Flow meter A; 18-Flow meter B; 19-Flow meter C; 20-Flow meter D; 21-Flow meter E; 22-Flow meter F; 23-Isolation valve for main condensate pipeline to Unit 2; 24-Main condensate pipeline to Unit 2; 25-Isolation valve for main condensate pipeline to Unit 1; 26-Main condensate pipeline to Unit 1; 27-Isolation valve for condenser to Unit 2; 28-Isolation valve for condenser to Unit 1; 29-Condenser A to Unit 2; 30-Condenser B to Unit 2; 31-Condenser C to Unit 2; 32-Condenser A to Unit 1; 33-Condenser B to Unit 1; 34-Condenser C to Unit 1. Detailed Implementation

[0039] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0040] This invention makes full use of the existing resources of nuclear power plants and simultaneously completes the recycling of steam condensate from two units by adding a steam supply condensate return system, thereby achieving energy conservation and environmental protection in the production process and improving the economic benefits of nuclear power steam heating projects while ensuring the safe and stable operation of existing nuclear power units.

[0041] Embodiments of the present invention disclose a nuclear power plant industrial steam condensate return system, such as... Figure 1 As shown, it includes:

[0042] The first condensate main pipe is connected to the first unit's condensate main pipe 26 and the first unit's condenser via two branch lines at the rear end.

[0043] The first unit's condensers include three units connected in parallel: first unit condenser A 32, first unit condenser B 33, and first unit condenser C 34.

[0044] An isolation valve 25 for supplying the main condensate pipeline of the first unit is installed on the branch line connected to the main condensate pipeline of the first unit; an isolation valve 28 for supplying the condenser of the first unit is installed on the branch line connected to the condenser of the first unit.

[0045] The second condensate header is connected to the second unit's condensate main pipeline 24 and the second unit's condenser via two branch lines at the rear end.

[0046] The second unit condenser includes three units connected in parallel: second unit condenser A29, second unit condenser B30, and second unit condenser C31.

[0047] An isolation valve 23 for supplying the main condensate pipeline of the second unit is installed on the branch line connected to the main condensate pipeline of the second unit; an isolation valve 27 for supplying the condenser of the second unit is installed on the branch line connected to the condenser of the second unit.

[0048] Two primary feedwater preheating systems, namely the first primary feedwater preheating system 1 and the second primary feedwater preheating system 2, are connected to the front end of the first condensate header through the condensate pipeline of the first unit and the condensate pipeline of the second unit, respectively, to transport the collected condensate after heat exchange of the steam conversion equipment to the condensate header.

[0049] Specifically,

[0050] A first unit condensate isolation valve A5 is installed on the first unit condensate pipeline A connected after the first-stage water preheating system 1, and a second unit condensate isolation valve A6 is installed on the second unit condensate pipeline A connected after the first-stage water preheating system 1.

[0051] A first unit condensate isolation valve B8 is installed on the first unit condensate pipeline B connected after the second-stage water preheating system 2, and a second unit condensate isolation valve B7 is installed on the second unit condensate pipeline B connected after the second-stage water preheating system 2.

[0052] Two primary feedwater preheating systems, namely the third primary feedwater preheating system 3 and the fourth primary feedwater preheating system 4, are connected to the front end of the first condensate header through the condensate pipeline of the first unit and the condensate pipeline of the second unit, respectively, to transport the condensate collected after heat exchange of the steam conversion equipment to the condensate header.

[0053] Specifically,

[0054] A first unit condensate isolation valve C10 is installed on the first unit condensate pipeline C connected after the third-level water preheating system 3, and a second unit condensate isolation valve C9 is installed on the second unit condensate pipeline C connected after the third-level water preheating system 3.

[0055] A first unit condensate isolation valve D11 is installed on the first unit condensate pipeline D connected after the fourth primary water preheating system 4, and a second unit condensate isolation valve D12 is installed on the second unit condensate pipeline D connected after the fourth primary water preheating system 4.

[0056] Multiple flow meters are connected in parallel on each condensate tap, specifically:

[0057] At least three flow meters are installed on the first condensate canal: flow meter D20, flow meter E21, and flow meter F22.

[0058] The second condensate canal is equipped with the above three flow meters, namely flow meter A17, flow meter B18, and flow meter C19.

[0059] The first condensate main pipe is equipped with a temperature measuring device and a pressure measuring device; namely, condensate main pipe thermometer B15; 16-condensate main pipe pressure gauge B16;

[0060] The second condensate main pipe is equipped with a temperature measuring device and a pressure measuring device, namely a condensate main pipe thermometer A13 and a condensate main pipe pressure gauge A14.

[0061] An embodiment of the present invention also discloses a method for controlling the return water of industrial steam supply condensate in a nuclear power plant, comprising:

[0062] During normal operation of the unit, the condensate after heat exchange in the steam conversion equipment flows back to the main condensate pipeline of the unit through the condensate header.

[0063] The isolation valves of the main condensate pipeline of Unit 1 and Unit 2 are opened, while the isolation valves for the condenser of Unit 1 and Unit 2 are closed.

[0064] When the electric isolation valve of the main steam pipeline system of the first unit is fully open or fully closed, it will open or close the electric isolation valve on the condensate pipeline of the first unit in conjunction with the valve position, and at the same time close or open the electric isolation valve on the condensate pipeline of the second unit.

[0065] When the electric isolation valve of the main steam pipeline system of the second unit is fully open or fully closed, it will open or close the electric isolation valve on the condensate pipeline of the second unit in conjunction with the first unit.

[0066] During unit startup, the condensate after heat exchange in the steam conversion equipment flows to the condensate header through the condensate header. The isolation valves of the main condensate pipeline of Unit 1 and Unit 2 are closed, while the isolation valves for the condenser of Unit 1 and Unit 2 are opened, allowing the condensate to flow to the condenser through the condensate header.

[0067] Also includes:

[0068] When the liquid level observed in the evaporator is high, the isolation valve for the condenser of the first unit and the isolation valve for the condenser of the second unit will be opened automatically.

[0069] When the deaerator on the conventional island is at a high water level, the isolation valve for the condenser of the first unit and the isolation valve for the condenser of the second unit will be opened automatically.

[0070] To further understand the present invention, the following detailed description of the nuclear power plant industrial steam condensate return system and control method provided by the present invention is given in conjunction with embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0071] Example 1

[0072] The condensate from the main steam after heat exchange in the steam conversion equipment is drawn out through the condensate pipelines at the rear of the first-stage feedwater preheating system 1, the second-stage feedwater preheating system 2, the third-stage feedwater preheating system 3, and the fourth-stage feedwater preheating system 4. It then flows through the first unit condensate isolation valve A5, the second unit condensate isolation valve A6, the first unit condensate isolation valve B8, and the second unit condensate isolation valve B7 to the first condensate header, which is then returned to the second loop condensate condenser of the first unit or the main condensate pipeline of the first unit. Conversely, it flows through the first unit condensate isolation valve C10, the second unit condensate isolation valve C9, the first unit condensate isolation valve D11, and the second unit condensate isolation valve D12 to the second condensate header, which is then returned to the second loop condensate condenser of the second unit or the main condensate pipeline of the second unit.

[0073] The temperature and pressure of the first and second condensate headers were measured respectively.

[0074] During normal operation, the condensate from the main steam after heat exchange in the steam conversion equipment flows to the main condensate pipeline through isolation valve 25 for the main condensate pipeline of the first unit and isolation valve 23 for the main condensate pipeline of the second unit. Under the start-up condition of the unit, the condensate from the outlet of the first preheater is collected in the main pipe and then flows to the condenser through isolation valve 28 for the condenser of the first unit and isolation valve 27 for the condenser of the second unit, thereby ensuring the safety and stability of the secondary loop condensate system under different operating conditions.

[0075] The condensate isolation valves A5 (first unit), A6 (second unit), B7 (second unit), B8 (first unit), C9 (second unit), C10 (first unit), D11 (first unit), and D12 (second unit) can be controlled to open and close locally and in the control room.

[0076] When the electric isolation valve of the main steam pipeline system of the first unit is fully open, the first unit condensate isolation valves A5, B8, C10, and D11 on the condensate pipeline of the first unit will be interlocked and opened; at the same time, the second unit condensate isolation valves A6, B7, C9, and D12 on the condensate pipeline of the second unit will be interlocked and closed.

[0077] When the electric isolation valve of the main steam pipeline system of the first unit is fully closed, the first unit condensate isolation valves A5, B8, C10, and D11 on the condensate pipeline of the first unit will be interlocked and closed to ensure that the main steam condensate of the first unit flows back to the first unit, so as to prevent the secondary circuit media of the two units from mixing.

[0078] When the electric isolation valve of the main steam pipeline system of the second unit is fully open, the second unit condensate isolation valves A6, B7, C9, and D12 on the condensate pipeline of the second unit will be interlocked and opened; at the same time, the first unit condensate isolation valves A5, B8, C10, and D11 on the condensate pipeline of the first unit will be interlocked and closed.

[0079] When the electric isolation valve of the main steam pipeline system of the second unit is fully closed, the second unit condensate isolation valves A6, B7, C9, and D12 on the condensate pipeline of the second unit will be interlocked and closed to ensure that the main steam condensate of the second unit flows back to the second unit, so as to prevent the secondary circuit media of the two units from mixing.

[0080] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0081] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A nuclear power plant industrial steam condensate backwater system characterized by, Comprise: The first condensate main pipe, the rear end is connected to the first unit condensate main pipe and the first unit condenser through two branches respectively; The second condensate main pipe, the rear end is connected to the second unit condensate main pipe and the second unit condenser through two branches respectively; Two primary feedwater preheating systems, through the condensate pipe at the rear end and the front end of the first condensate main pipe are connected, the collected steam conversion equipment after heat exchange condensate is transported to the condensate main pipe; Two primary feedwater preheating systems, through the condensate pipe at the rear end and the front end of the second condensate main pipe are connected, the collected steam conversion equipment after heat exchange condensate is transported to the condensate main pipe; Each condensate main pipe is provided with a plurality of flow meters in parallel, The branch connected with the first unit condensate main pipe is provided with a first unit main condensate pipe isolation valve; The branch connected with the first unit condenser is provided with a first unit condenser isolation valve; The branch connected with the second unit condensate main pipe is provided with a second unit main condensate pipe isolation valve; The branch connected with the second unit condenser is provided with a second unit condenser isolation valve; Two primary feedwater preheating systems are connected to the front end of the first condensate main pipe through the first unit condensate pipe and the second unit condensate pipe respectively, Two primary feedwater preheating systems are connected to the front end of the second condensate main pipe through the first unit condensate pipe and the second unit condensate pipe respectively, Each first unit condensate pipe is provided with a first electric isolation valve; Each second unit condensate pipe is provided with a second electric isolation valve; The first condensate main pipe is communicated with the second condensate main pipe.

2. The nuclear power plant industrial steam condensate backwater system of claim 1, wherein, The first condensate main pipe is provided with a temperature measuring device and a pressure measuring device; The second condensate main pipe is provided with a temperature measuring device and a pressure measuring device.

3. The nuclear power plant industrial steam condensate return system of claim 1, wherein, The flow meter has at least three.

4. A method for controlling the condensate water return of an industrial steam supply of a nuclear power plant using the condensate water return system according to any one of claims 1 to 3, characterized in that, Comprise: When the unit is running normally, the condensate after heat exchange in the steam conversion equipment is returned to the main condensate pipe of the unit through the condensate main pipe; When the unit is started, the condensate after heat exchange in the steam conversion equipment flows to the condenser through the condensate main pipe.

5. The nuclear power plant industrial steam condensate backwater control method according to claim 4, characterized by, When the unit is running normally, The first unit main condensate pipe isolation valve and the second unit main condensate pipe isolation valve are opened, and the first unit condenser isolation valve and the second unit condenser isolation valve are closed; When the electric isolation valve of the heating main steam pipeline system of the first unit is fully opened or fully closed, the electric isolation valve on the first unit condensate pipe is opened or closed, and the electric isolation valve on the second unit condensate pipe is closed or opened; When the electric isolation valve of the heating main steam pipeline system of the second unit is fully opened or fully closed, the electric isolation valve on the second unit condensate pipe is opened or closed, and the electric isolation valve on the first unit condensate pipe is closed or opened.

6. The nuclear power plant industrial steam condensate backwater control method according to claim 4, characterized by, When the unit is started, the first unit main condensate pipe isolation valve and the second unit main condensate pipe isolation valve are closed, and the first unit condenser isolation valve and the second unit condenser isolation valve are opened, so that the condensate flows to the condenser through the condensate main pipe.

7. The nuclear power plant industrial steam condensate backwater control method according to claim 4, characterized by, Further comprise: When the evaporator observes high liquid level, the first unit condenser isolation valve and the second unit condenser isolation valve are automatically opened; When the conventional island deaerator is at high water level, the first unit condenser isolation valve and the second unit condenser isolation valve are automatically opened.

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