Feed water oxygen adding system of thermal system of thermal power unit

Abstract

The application provides a feedwater oxygen adding system of a thermal system of a thermal power unit. The system comprises a solubilizer, an air inlet pipeline, a water inlet pipeline, a low-pressure feedwater oxygen adding branch, a high-pressure feedwater oxygen adding branch, a high-pressure feedwater oxygen adding branch, a low-pressure feedwater oxygen adding branch, a DCS electric control cabinet, the solubilizer is provided with an air inlet, a water inlet and a water outlet, the solubilizer is used for preparing desalted water and oxygen into oxygen-rich water, the air inlet pipeline is connected with the air inlet and used for inputting oxygen into the solubilizer, the water inlet pipeline is connected with the water inlet and used for inputting desalted water into the solubilizer, the low-pressure feedwater oxygen adding branch is connected with the water outlet and an oxygen adding inlet of a low-pressure feedwater system, the high-pressure feedwater oxygen adding branch is connected with the water outlet and an oxygen adding inlet of a high-pressure feedwater system, the high-pressure feedwater oxygen adding branch is connected with the water outlet and an oxygen adding inlet of a low-pressure feedwater system, and the low-pressure feedwater oxygen adding branch is connected with the water outlet and an oxygen adding inlet of a high-pressure feedwater system. The system realizes comprehensive and whole-process coverage of the whole thermal system and is suitable for flexible peak regulation.

Description

Technical Field

[0001] This application belongs to the technical field of large-scale thermal power generation steam turbine units, specifically, it relates to a feedwater oxygenation system for the thermal system of a thermal power unit. Background Technology

[0002] Boiler feedwater oxygenation is an advanced process to alleviate scaling on the heating surfaces of supercritical boilers, deposition corrosion of turbine flow components, and accelerated corrosion of the drainage system. It is also an effective measure to reduce the large amount of chemical reagents used in thermal power production and to reduce the discharge of acid and alkaline wastewater. Existing feedwater oxygenation technologies are segmented, targeting low-pressure feedwater systems, high-pressure feedwater systems, or high-pressure heater drainage systems. They fail to truly achieve metal passivation protection covering the entire steam-water flow path of the thermal system, especially lacking oxygenation technology specifically for low-pressure drainage systems. In fact, taking supercritical units as an example, the temperature of the low-pressure drainage system is typically between 100℃ and 200℃, a key area for corrosion of metals such as carbon steel. Furthermore, two-point oxygenation technology requires opening the deaerator's exhaust valve, making it impossible to achieve oxygenation passivation protection for the deaerator itself.

[0003] In addition, large thermal power units are facing the challenge of flexible peak shaving when new energy sources come online. As the unit load rises and falls rapidly, the feedwater flow fluctuates accordingly, causing large fluctuations in the dissolved oxygen content of the water-steam system. Existing oxygenation technology cannot achieve intelligent operation of feedwater oxygenation treatment under flexible peak shaving. Utility Model Content

[0004] The technical problem addressed by this application is: how to achieve comprehensive and full-process coverage of the entire thermal system, and how to make oxygenation regulation flexible for peak shaving.

[0005] This application provides a feedwater oxygenation system for a thermal power unit's thermal system, the feedwater oxygenation system comprising:

[0006] A solubilizer having an air inlet, a water inlet, and a drain outlet, the solubilizer being used to prepare oxygen-enriched water from demineralized water and oxygen;

[0007] An air inlet line, which is connected to the air inlet for supplying oxygen to the solubilizer;

[0008] A water inlet pipe is connected to the water inlet for supplying demineralized water to the solubilizer;

[0009] A low-pressure water supply oxygenation branch line is provided, which connects the drain outlet and the low-pressure water supply system oxygenation inlet.

[0010] A high-pressure water supply oxygenation branch line is provided, which connects the drain outlet and the oxygenation inlet of the high-pressure water supply system.

[0011] A high-pressure condensate-drainage oxygenation branch, which connects the drain outlet and the low-pressure condensate-drainage system oxygenation inlet;

[0012] A low-pressure condensate oxygenation branch is provided, which connects the drain outlet and the high-pressure condensate oxygenation inlet of the system.

[0013] The DCS control cabinet is used to control the start / stop and flow rate of the low-pressure water supply oxygenation branch, the high-pressure water supply oxygenation branch, the high-pressure water supply condensate oxygenation branch, and the low-pressure water supply condensate oxygenation branch.

[0014] Optionally, the water oxygenation system further includes an online dissolved oxygen measurement branch, which is connected to the drain outlet for measuring the oxygen content of the oxygen-enriched water, and the online dissolved oxygen measurement branch is connected to the DCS control cabinet via a branch line communication connection.

[0015] Optionally, the water supply oxygenation system further includes a pressure sensor, which is connected to the drain outlet and communicates with the DCS control cabinet via a branch line.

[0016] Optionally, along the flow direction of oxygen-enriched water in the low-pressure water supply oxygenation branch, the low-pressure water supply oxygenation branch includes a ball valve, a Y-type filter, an electric shut-off valve, and a flow sensor arranged in sequence. The shut-off valve is connected to the DCS control cabinet via a branch line communication, and the DCS control cabinet is used to control the flow rate of the electric shut-off valve.

[0017] Optionally, along the flow direction of oxygen-enriched water in the high-pressure water supply oxygenation branch, the high-pressure water supply oxygenation branch includes a ball valve, a Y-type filter, a booster pump, a ball valve, a check valve, a pressure indicator, an electric ball valve, and a check valve arranged in sequence. The booster pump and the electric ball valve are respectively connected to the DCS control cabinet via branch lines. The DCS control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

[0018] Optionally, along the flow direction of oxygen-enriched water in the low-pressure hydrophobic oxygenation branch, the low-pressure hydrophobic oxygenation branch includes a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve arranged in sequence. The booster pump, the flow sensor, and the electric ball valve are respectively connected to the DCS electrical control cabinet via branch lines for communication. The DCS electrical control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

[0019] Optionally, along the flow direction of oxygen-enriched water in the high-pressure heater hydrophobic oxygenation branch, the high-pressure heater hydrophobic oxygenation branch includes a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve arranged in sequence. The booster pump, the flow sensor, and the electric ball valve are respectively connected to the DCS electrical control cabinet via branch lines for communication. The DCS electrical control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

[0020] Optionally, along the oxygen-enriched water flow direction within the online dissolved oxygen measurement branch, the online dissolved oxygen measurement branch includes, in sequence, an instrument valve, a float flow meter, and an online dissolved oxygen meter, the online dissolved oxygen meter being connected to the DCS electrical control cabinet via a branch line communication connection.

[0021] The feedwater oxygenation system for a thermal power unit provided in this application has the following technical advantages:

[0022] (1) To truly achieve metal passivation protection covering the entire steam-water flow range of the thermal system, especially for oxygenation technology for low-pressure condensate systems. In fact, taking supercritical units as an example, the temperature of low-pressure condensate systems is usually between 100℃ and 200℃, which is the key area for corrosion of metals such as carbon steel.

[0023] (2) The intelligent oxygenation equipment of the high-pressure water supply system automatically opens the deaerator operation exhaust valve, realizing the oxygenation passivation protection of the deaerator body.

[0024] (3) It effectively solves the problem of intelligent operation of feedwater oxygenation treatment under the flexible peak shaving of large thermal power units. Attached Figure Description

[0025] Figure 1 This is an overall architecture diagram of the feedwater oxygenation system of a thermal power unit according to one or more embodiments.

[0026] Figure 2 for Figure 1 The diagram shows the symbolic representation of the text.

[0027] Figure 3 This is a schematic diagram of the low-pressure feedwater oxygenation branch of the feedwater oxygenation system of a thermal power unit according to one or more embodiments.

[0028] Figure 4 This is a schematic diagram of the high-pressure feedwater oxygenation branch of the feedwater oxygenation system of a thermal power unit according to one or more embodiments.

[0029] Figure 5 This is a schematic diagram of the low-pressure / high-pressure hydrophobic oxygenation branch of a thermal power unit according to one or more embodiments. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] Before describing the various embodiments of this application in detail, the technical concept of this application is first briefly described: Currently, when oxygenating boiler feedwater, it is difficult to achieve comprehensive and full-process coverage of the entire thermal system, and the adjustment of oxygenation technology cannot achieve flexible peak shaving. Therefore, the feedwater oxygenation system for thermal power units provided in this application introduces oxygen-enriched water into each oxygenation inlet through four oxygenation branches. Based on the different characteristics of the system to be oxygenated, the oxygen content is intelligently adjusted through the DCS control cabinet, achieving segmented and precise oxygenation operation. This truly realizes metal passivation protection covering the entire water-steam process range of the thermal system, effectively solving the problem of intelligent operation of feedwater oxygenation under flexible peak shaving in large thermal power units. The specific principle of the feedwater oxygenation system for thermal power units of this application will be described below with reference to more embodiments.

[0032] Specifically, such as Figure 1 and Figure 2 As shown, the feedwater oxygenation system of the thermal power unit in this embodiment includes a solubilizer 10, an air inlet pipe 20, a water inlet pipe 30, a low-pressure feedwater oxygenation branch 40, a high-pressure feedwater oxygenation branch 50, a high-pressure heater condensate oxygenation branch 60, a low-pressure heater condensate oxygenation branch 70, and a DCS control cabinet 80. The solubilizer has an air inlet, a water inlet, and a drain outlet. The solubilizer is used to prepare oxygen-enriched water from demineralized water and oxygen. Air inlet pipe 20 is connected to the air inlet to supply oxygen to the solubilizer 10; water inlet pipe 30 is connected to the water inlet to supply demineralized water to the solubilizer 10; low-pressure feedwater oxygenation branch 40 is connected to the drain outlet and the low-pressure feedwater system oxygenation inlet; high-pressure feedwater oxygenation branch 50 is connected to the drain outlet and the high-pressure feedwater system oxygenation inlet; high-pressure heater condensate oxygenation branch 60 is connected to the drain outlet and the low-pressure heater condensate oxygenation inlet; low-pressure heater condensate oxygenation branch 70 is connected to the drain outlet and the high-pressure heater condensate oxygenation inlet; the DCS control cabinet is used to control the start / stop and feedwater flow rate of low-pressure feedwater oxygenation branch 40, high-pressure feedwater oxygenation branch 50, high-pressure heater condensate oxygenation branch 60, and low-pressure heater condensate oxygenation branch 70 respectively. DCS control cabinet 80 is used to control the start / stop and water flow rate of low-pressure water supply oxygenation branch 40, high-pressure water supply oxygenation branch 50, high-pressure heater condensate oxygenation branch 60, and low-pressure heater condensate oxygenation branch 70 respectively. Figure 1 The dashed lines in the diagram represent the DCS control cabinet 80 communicating with various devices via branch lines, while the solid lines represent the connections between the devices via pipelines to deliver oxygen-enriched water.

[0033] In one or more embodiments, the water supply oxygenation system further includes an online dissolved oxygen measurement branch 90, which is connected to the drain outlet for measuring the oxygen content of the oxygen-enriched water. The online dissolved oxygen measurement branch 90 is also connected to the DCS control cabinet via a branch line for communication. In the direction of oxygen-enriched water flow within the online dissolved oxygen measurement branch 90, the branch includes, in sequence, an instrument valve 91, a float flowmeter 92, and an online dissolved oxygen meter 93, which is connected to the DCS control cabinet 80 via a branch line for communication. The solubility value measured by the online dissolved oxygen meter 93 is transmitted to the DCS control cabinet 80, which adjusts the actions of each branch line based on the solubility value. When the solubility value deviates from the dissolved oxygen setting range, the automatic interlocking deaerator operates, and the exhaust valve regulating valve activates, enabling the start and stop of the intelligent oxygenation equipment in the high-pressure water supply system. Furthermore, the water supply oxygenation system also includes a pressure sensor PT, which is connected to the drain outlet and is also connected to the DCS control cabinet via a branch line for communication.

[0034] In one or more embodiments, such as Figure 3 As shown, along the oxygen-enriched water flow direction within the low-pressure feedwater oxygenation branch 40, the low-pressure feedwater oxygenation branch 40 includes a ball valve, a Y-type filter, an electric shut-off valve, and a flow sensor arranged in sequence. The shut-off valve is connected to the DCS control cabinet via a branch line communication. The DCS control cabinet 80 is used to control the flow rate of the electric shut-off valve.

[0035] In one or more embodiments, such as Figure 4 As shown, along the flow direction of oxygen-enriched water in the high-pressure feedwater oxygenation branch, the high-pressure feedwater oxygenation branch includes, in sequence, a ball valve, a Y-type filter, a booster pump, a ball valve, a check valve, a pressure indicator, an electric ball valve, and a check valve. The booster pump and the electric ball valve are respectively connected to the DCS control cabinet via branch lines. The DCS control cabinet is used to control the flow rate of the electric ball valve and to regulate the booster pump. The high-pressure feedwater oxygenation branch, through the booster pump power source and automatic logic switching valve, sequentially achieves the purpose of continuous oxygenation along the water-steam circulation system flow: deaerator A / B downcomer pipes → #3 high-pressure heater and its pipes → #2 high-pressure heater and its pipes → #1 high-pressure heater and its pipes → economizer and its pipes → water-cooled wall and its pipes → steam-water separator.

[0036] In one or more embodiments, along the flow direction of oxygen-enriched water in the low-pressure hydrophobic oxygenation branch, the low-pressure hydrophobic oxygenation branch includes, in sequence, a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve. The booster pump, flow sensor, and electric ball valve are each connected to a DCS control cabinet via branch lines. The DCS control cabinet is used to control the flow rate of the electric ball valve and to regulate the booster pump. Along the flow direction of oxygen-enriched water in the high-pressure hydrophobic oxygenation branch, the high-pressure hydrophobic oxygenation branch includes, in sequence, a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve. The booster pump, flow sensor, and electric ball valve are each connected to a DCS control cabinet via branch lines. The DCS control cabinet is used to control the flow rate of the electric ball valve and to regulate the booster pump.

[0037] The aforementioned low-pressure heater / high-pressure heater condensate and oxygenation branch, powered by a booster pump and an automatic logic switch, sequentially achieves the oxygenation purpose along the condensate collection system process: #8 low-pressure heater condensate pipe → #7 low-pressure heater condensate pipe → #6 low-pressure heater condensate pipe → #5 low-pressure heater condensate pipe, and #3 high-pressure heater condensate pipe → #2 high-pressure heater condensate pipe → #1 high-pressure heater condensate pipe.

[0038] Each regulating valve actuator on the above-mentioned branch is connected to the DCS program integrated control screen via branch communication, and is mainly associated with the unit feedwater flow signal. Each actuator is also associated with the deaerator inlet, economizer inlet / steam-water separator outlet, and low / high condensate online O2 meter in the centralized water and steam sampling system. It is also interlocked with the economizer inlet online CC meter for protection. When the oxygenation protection is deactivated, it switches in reverse to the feedwater ammonia pump to increase the frequency, realizing intelligent switching between feedwater AVT(O) and OT water conditions.

[0039] The feedwater oxygenation system for thermal power units provided in this application has the following beneficial effects: (1) It truly achieves metal passivation protection covering the entire steam-water flow range of the thermal system, especially for oxygenation technology in low-pressure condensate systems. In fact, taking supercritical units as an example, the temperature of low-pressure condensate systems is usually between 100℃ and 200℃, which is a key area for corrosion of metals such as carbon steel. (2) The intelligent oxygenation equipment for high-pressure feedwater systems automatically opens the deaerator's exhaust valve, realizing oxygenation passivation protection for the deaerator body. (3) It effectively solves the problem of intelligent operation of feedwater oxygenation treatment under flexible peak shaving of large thermal power units.

[0040] The specific embodiments of this application have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that modifications and improvements can be made to these embodiments without departing from the principles and spirit of this application as defined by the claims and their equivalents, and such modifications and improvements should also be within the protection scope of this application.

Claims

1. A feedwater oxygenation system for a thermal power unit, characterized in that, The water supply oxygenation system includes: A solubilizer having an air inlet, a water inlet, and a drain outlet, the solubilizer being used to prepare oxygen-enriched water from demineralized water and oxygen; An air inlet line, which is connected to the air inlet for supplying oxygen to the solubilizer; A water inlet pipe is connected to the water inlet for supplying demineralized water to the solubilizer; A low-pressure water supply oxygenation branch line is provided, which connects the drain outlet and the low-pressure water supply system oxygenation inlet. A high-pressure water supply oxygenation branch line is provided, which connects the drain outlet and the oxygenation inlet of the high-pressure water supply system. A high-pressure condensate-drainage oxygenation branch, which connects the drain outlet and the low-pressure condensate-drainage system oxygenation inlet; A low-pressure condensate oxygenation branch is provided, which connects the drain outlet and the high-pressure condensate oxygenation inlet of the system. The DCS control cabinet is used to control the start / stop and flow rate of the low-pressure water supply oxygenation branch, the high-pressure water supply oxygenation branch, the high-pressure water supply condensate oxygenation branch, and the low-pressure water supply condensate oxygenation branch.

2. The feedwater oxygenation system of the thermal power unit according to claim 1, characterized in that, The water supply oxygenation system also includes an online dissolved oxygen measurement branch, which is connected to the drain outlet to measure the oxygen content of the oxygen-enriched water, and the online dissolved oxygen measurement branch is connected to the DCS control cabinet via a branch line communication connection.

3. The feedwater oxygenation system of the thermal power unit according to claim 2, characterized in that, The water supply oxygenation system also includes a pressure sensor, which is connected to the drain outlet and has a branch-line communication connection with the DCS control cabinet.

4. The feedwater oxygenation system of the thermal power unit according to claim 1, characterized in that, Along the oxygen-enriched water flow direction within the low-pressure water supply oxygenation branch, the low-pressure water supply oxygenation branch includes a ball valve, a Y-type filter, an electric shut-off valve, and a flow sensor arranged in sequence. The shut-off valve is connected to the DCS electrical control cabinet via a branch line communication, and the DCS electrical control cabinet is used to control the flow rate of the electric shut-off valve.

5. The feedwater oxygenation system of the thermal power unit according to claim 1, characterized in that, Along the oxygen-enriched water flow direction within the high-pressure water supply oxygenation branch, the high-pressure water supply oxygenation branch includes, in sequence, a ball valve, a Y-type filter, a booster pump, a ball valve, a check valve, a pressure indicator, an electric ball valve, and a check valve. The booster pump and the electric ball valve are respectively connected to the DCS control cabinet via branch lines. The DCS control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

6. The feedwater oxygenation system of the thermal power unit according to claim 1, characterized in that, Along the flow direction of oxygen-enriched water within the low-pressure hydrophobic oxygenation branch, the low-pressure hydrophobic oxygenation branch includes a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve arranged in sequence. The booster pump, the flow sensor, and the electric ball valve are respectively connected to the DCS electrical control cabinet via branch lines for communication. The DCS electrical control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

7. The feedwater oxygenation system of the thermal power unit according to claim 1, characterized in that, Along the flow direction of oxygen-enriched water within the high-pressure heater's hydrophobic oxygenation branch, the high-pressure heater's hydrophobic oxygenation branch includes, in sequence, a ball valve, a Y-type filter, a booster pump, a plunger pump, a flow sensor, a pressure indicator, an electric ball valve, and a check valve. The booster pump, the flow sensor, and the electric ball valve are respectively connected to the DCS electrical control cabinet via branch lines. The DCS electrical control cabinet is used to control the flow rate of the electric ball valve and to adjust the booster pump.

8. The feedwater oxygenation system of the thermal power unit according to claim 2, characterized in that, Along the oxygen-enriched water flow direction within the online dissolved oxygen measurement branch, the online dissolved oxygen measurement branch includes, in sequence, an instrument valve, a float flow meter, and an online dissolved oxygen meter, the online dissolved oxygen meter being connected to the DCS electrical control cabinet via a branch line communication connection.

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