A water replenishing system and method capable of realizing unpowered vacuum pre-deaeration

Abstract

The application discloses a water supplement system and method capable of realizing unpowered vacuum pre-deaeration, and the water supplement system comprises a vacuum pre-deaerator, which is used for atomizing and pre-deaerating desalted water which needs to be supplemented into a system, and simultaneously performing mixing and heat exchange; non-condensable gas is extracted through an original condenser vacuum pump and directly discharged without passing through the condenser; and the desalted water after being heated and pre-deaerated is further subjected to deep deaeration and heat exchange through the condenser fine mist water supplement device. The vacuum pre-deaerator of the application has a simple structure compared with a common vacuum deaerator, can realize a very small volume, and can satisfy large-flow pre-deaeration. The desalted water which needs to be supplemented is subjected to two-stage deaeration and heating, and finally basically reaches a saturation temperature, so that the loss caused by supercooling is reduced. The non-condensable gas is directly discharged without passing through the condenser, so that the oxygen dissolution of the condenser is reduced, the heat exchange efficiency of the condenser is improved, the oxygen corrosion of the condenser and the low-level heater is reduced, the system vacuum degree is improved, and the thermal efficiency of the unit is improved.

Description

Technical Field

[0001] This invention relates to the field of demineralized water replenishment technology for thermal power plants, specifically to a replenishment system and method that can achieve non-powered vacuum pre-deoxygenation. Background Technology

[0002] Currently, makeup water for water-cooled thermal power units is generally supplied to the condenser via a demineralized water pump. Some units also use a method of supplying makeup water directly to the condenser throat, but atomization effect is not considered. Some power plants in China have achieved certain results by adopting atomizing nozzle technology to atomize the demineralized water and spray it into the condenser throat.

[0003] In reality, the makeup water rate of existing water-cooled condensing thermal power units is less than 1.5%. Based on a steam flow rate of 1000 t / h for a 300MW unit, the makeup water volume is 15 t / h, which is relatively small overall, and the total amount of oxygen or other non-condensable gases in the water is also low. However, with the rapid development of new energy sources in China, more and more thermal power units have undergone heating and steam extraction retrofits, and this number will continue to increase in the future. After these retrofits, changes in water quality or the inability to recover externally supplied steam can lead to a significant increase in makeup water volume, sometimes reaching 200 t / h for a single unit. The large amount of oxygen or other non-condensable gases introduced by the makeup water can cause excessive dissolved oxygen in the condensate, a decrease in condenser heat exchange efficiency, and significant subcooling heat loss due to the low temperature of the directly added demineralized water.

[0004] The current method of injecting water into the condenser throat can meet the requirements for deoxygenation and reducing subcooling to some extent. However, a single spray water injection method is insufficient to heat the water to the condenser saturation temperature. In addition, oxygen or other non-condensable gases released from the water will be released at the throat. Related studies have shown that when non-condensable gases rise in the steam, it will greatly affect the heat exchange efficiency of the downstream condenser, thereby reducing the unit's economic efficiency.

[0005] Existing vacuum deaerators can effectively solve the problem of deoxygenation from water replenishment, but their complex structure, large size, and the need for additional vacuum pumps make actual modification difficult and maintenance demanding. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention aims to provide a water replenishment system and method that can achieve non-powered vacuum pre-deoxygenation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A water supply system capable of achieving non-powered vacuum pre-deaeration includes a vacuum pre-deaerator, a condenser fine mist water supply device, a deaerator inlet water pipe, a deaerator inlet water pump, a deaerator drain pipe, a condenser water supply atomizing pump, a water supply device inlet pipe, a low-cylinder exhaust steam extraction pipe, a low-cylinder exhaust steam extraction valve, a deaerator heating steam pipe, a deaerator exhaust pipe, a deaerator vacuum gauge, and a deaerator exhaust valve.

[0009] The vacuum pre-deaerator includes a main shell, inside which are provided an internal water inlet pipe, a high-flow-rate demineralized water nozzle, an internal steam distribution pipe, a steam outlet, and a demister; the internal water inlet pipe is connected to the high-flow-rate demineralized water nozzle, which faces upward; the internal steam distribution pipe has several upward-facing steam outlets evenly arranged on it, and each steam outlet is connected to the internal steam distribution pipe; the demister is located on the inner top wall of the main shell.

[0010] The condenser fine mist water supply device is connected to the low-pressure cylinder exhaust pipe, and has a fine mist water supply nozzle structure inside, which faces the condenser inlet; the deaerator inlet water pump is connected to the internal inlet water pipe through the deaerator inlet water pipe, and the deaerator drain pipe is connected to the bottom of the outer shell of the vacuum pre-deaerator and the inlet of the condenser water supply atomizing pump, respectively. The water supply device inlet pipe is connected to the outlet of the condenser water supply atomizing pump and the fine mist water supply nozzle structure, respectively; the low-pressure cylinder exhaust steam extraction pipe is connected to the upper part of the condenser fine mist water supply device and the low-pressure cylinder exhaust steam extraction valve, respectively; the deaerator heating steam pipe is connected to the low-pressure cylinder exhaust steam extraction valve and the internal steam distribution pipe, respectively; the deaerator exhaust pipe is connected to the top of the inner shell of the vacuum pre-deaerator, and the deaerator exhaust pipe is equipped with a deaerator vacuum gauge and a deaerator exhaust valve.

[0011] Furthermore, several layers of water-baffles are provided around the inner wall of the outer shell body from top to bottom.

[0012] Furthermore, a level gauge is provided on the outside of the outer casing, and the probe of the level gauge extends into the outer casing.

[0013] Furthermore, a manhole is provided on the upper outer side of the outer shell body.

[0014] Furthermore, the outer shell of the vacuum pre-deaerator, the deaerator water inlet pipe, the deaerator drain pipe, the water replenisher inlet pipe, the low cylinder exhaust steam extraction pipe, the deaerator heating steam pipe, the deaerator exhaust pipe, the internal water inlet pipe, and the internal steam distribution pipe are all made of stainless steel.

[0015] Furthermore, the fine mist water supply nozzle structure includes three layers, each layer including a diversion pipe and several downward-facing fine mist water supply nozzles. The fine mist water supply nozzles are evenly arranged on the diversion pipe and connected to the diversion pipe. The diversion pipes of each layer are interconnected at the ends on the same side and connected to the water supply inlet pipe.

[0016] Furthermore, the fine mist water supply nozzle adopts a stainless steel 90° spiral nozzle.

[0017] Furthermore, the flow rate of the demineralized water high-flow nozzle (102) is 200 t / h.

[0018] The present invention also provides a method for operating the above-mentioned system, the specific process of which is as follows:

[0019] The deoxygenated water that needs to be pre-deoxygenated enters the internal inlet pipe through the deaerator inlet pump and the deaerator inlet pipe. After being atomized by the deoxygenated water high-flow nozzle, the atomized water is sprayed upward and then accumulates at the bottom of the vacuum pre-deaerator after rising and falling.

[0020] A small amount of exhaust steam from the low-pressure cylinder of the unit enters the fine mist water supply device of the condenser, and then enters the internal steam distribution pipe through the low-pressure cylinder exhaust steam extraction pipe, the low-pressure cylinder exhaust steam extraction valve, and the deaerator heating steam pipe. Finally, it is discharged into the outer shell of the vacuum pre-deaerator through the steam outlet. Since the temperature of this part of the low-pressure cylinder exhaust steam is slightly higher than the temperature cooled by the condenser, the exhaust steam flashes and releases latent heat inside the vacuum pre-deaerator. The saturated steam moves upward and the saturated water falls to the bottom.

[0021] The deoxygenated water that needs to be pre-deoxygenated is atomized by the high-flow-rate deoxygenated water nozzle and sprayed upwards, then falls downwards into the bottom of the vacuum pre-deoxygenator. During this process, it absorbs the latent heat released by the exhaust steam and also mixes and exchanges heat with the saturated steam. Both the atomization process and the heat exchange process release oxygen and other non-condensable gases, while simultaneously heating up and condensing more low-pressure cylinder exhaust steam.

[0022] The water that finally falls to the bottom of the vacuum pre-deaerator enters the fine mist water supply nozzle structure through the deaerator drain pipe, the condenser water supply atomizing pump, and the water supply inlet pipe. Under the action of differential pressure, the fine mist water supply nozzle structure sprays the water into the throat of the condenser. This part of the atomized water cools the exhaust steam of the low-pressure cylinder and moves towards the first cooling pipe at the condenser inlet, finally completing the deep deaeration and heating to the saturation temperature under the condenser pressure.

[0023] Inside the vacuum pre-deaerator, the uncondensed saturated steam from the low-pressure cylinder exhaust, along with most of the oxygen and non-condensable gases released from the demineralized water, rise upwards and pass through the demister, the deaerator exhaust pipe, and the deaerator exhaust valve, directly entering the condenser vacuum pump inlet and being discharged by the condenser vacuum pump. The deaerator vacuum gauge is used to measure the vacuum value inside the deaerator exhaust pipe.

[0024] Furthermore, in the above working method, by adjusting the opening of the low-cylinder exhaust steam extraction valve and the deaerator exhaust valve, the vacuum value of the deaerator vacuum gauge is adjusted to be slightly higher than the vacuum value of the condenser; by adjusting the deaerator inlet water pump, the amount of demineralized water to be added and the spray pressure of the demineralized water high-flow nozzle are adjusted; by adjusting the condenser water atomizing pump, the liquid level of the vacuum pre-deaerator and the spray pressure of the fine mist water nozzle structure are adjusted.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. The vacuum pre-deoxygenation device designed in this invention has a simple internal structure, is much smaller in size than a general vacuum deaerator at the same flow rate, and is easy to install. Furthermore, a high-flow-rate nozzle can meet the vacuum pre-deoxygenation requirements for demineralized water (200 t / h).

[0027] 2. In this invention, the exhaust outlet of the vacuum pre-deoxygenation device is connected to the existing condenser vacuum pump, avoiding the need to add a new vacuum pump. At the same time, most of the non-condensable gases can be discharged directly through the condenser vacuum pump in advance, preventing this part of the non-condensable gases from flowing through the entire condenser, thus improving condenser efficiency and reducing condenser terminal temperature difference.

[0028] 3. In this invention, the heating steam uses exhaust steam from a low-pressure cylinder, which has a higher temperature compared to the exhaust steam cooled by the condenser. The steam releases heat within the device until it reaches saturation, which is beneficial for improving the vacuum deoxygenation effect.

[0029] 4. In this invention, the demineralized water that needs to be replenished is first pre-deoxygenated and heated by a vacuum pre-deoxygenation device, and then deeply deoxygenated and heat-exchanged by a condenser fine mist water replenisher. This can heat the demineralized water that needs to be replenished to the saturation temperature, basically eliminating the supercooling loss.

[0030] 5. In this invention, pre-deoxygenated demineralized water is uniformly sprayed into the condenser through a condenser mist water dispenser, and undergoes deep deoxygenation during the heat exchange process of thorough mixing with the exhaust steam from the low-pressure cylinder. Since most of the non-condensable gases have already been released in the vacuum pre-deoxygenation device, the amount of non-condensable gases here is significantly reduced, improving the heat exchange efficiency of the subsequent condenser, reducing the terminal temperature difference, and further enhancing the heat exchange efficiency.

[0031] 6. In this invention, the demineralized water in the vacuum pre-deoxygenation device is sprayed upwards, which increases the residence time in the chamber.

[0032] 7. In this invention, the vacuum pre-deoxygenation device is equipped with three layers of baffles, which can prevent some water from flowing down the inner wall and improve the heat exchange and deoxygenation effect.

[0033] 8. In this invention, the condenser fine mist water supply device adopts a three-layer structure, which can meet the spray flow rate of 200t / h. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the water replenishment system that enables non-powered vacuum pre-deoxygenation in an embodiment of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to this embodiment.

[0036] This embodiment provides a water replenishment system that can achieve non-powered vacuum pre-deoxygenation, such as... Figure 1 As shown, it includes a vacuum pre-deaerator 1, a condenser fine mist water supply device 2, a deaerator inlet water pipe 3, a deaerator inlet water pump 4, a deaerator drain pipe 5, a condenser water supply atomizing pump 6, a water supply device inlet pipe 7, a low cylinder exhaust steam extraction pipe 8, a low cylinder exhaust steam extraction valve 9, a deaerator heating steam pipe 10, a deaerator exhaust pipe 11, a deaerator vacuum gauge 12, and a deaerator exhaust valve 13.

[0037] The vacuum pre-deaerator 1 includes a main shell, inside which are provided an internal water inlet pipe 101, a high-flow-rate demineralized water nozzle 102 with a flow rate of 200 t / h, an internal steam distribution pipe 104, a steam outlet 105, and a demister; the internal water inlet pipe 101 is connected to the high-flow-rate demineralized water nozzle 102, which faces upward; the internal steam distribution pipe 104 is evenly provided with several upward-facing steam outlets 105, each of which communicates with the internal steam distribution pipe 104; the demister is located on the inner top wall of the main shell;

[0038] The condenser mist water supply device 2 is connected to the low-pressure cylinder exhaust pipe, and has a fine mist water supply nozzle structure inside, which faces the condenser inlet; the deaerator inlet water pump 4 is connected to the inlet water internal pipe 101 through the deaerator inlet water pipe 3, and the deaerator drain pipe 5 is connected to the bottom of the outer shell of the vacuum pre-deaerator 1 and the inlet of the condenser water supply atomizing pump 6, respectively. The water supply device inlet pipe 7 is connected to the condenser water supply atomizing pump 6. The outlet of the chemical pump 6 and the fine mist water supply nozzle structure; the low cylinder exhaust steam extraction pipe 8 is connected to the upper part of the condenser fine mist water supply device 2 and the low cylinder exhaust steam extraction valve 9 respectively; the deaerator heating steam pipe 10 is connected to the low cylinder exhaust steam extraction valve 9 and the internal steam distribution pipe 104 respectively; the deaerator exhaust pipe 11 is connected to the top of the inner body of the vacuum pre-deaerator 1; the deaerator exhaust pipe 11 is equipped with a deaerator vacuum gauge 12 and a deaerator exhaust valve 13.

[0039] The working process of the above system is as follows: the deoxygenated water that needs to be pre-deoxygenated enters the internal water inlet pipe 101 through the deaerator inlet pump 4 and the deaerator inlet pipe 3. After being atomized by the deoxygenated water high-flow nozzle 102, the atomized water is sprayed upward and then accumulates at the bottom of the vacuum pre-deaerator 1 after rising and falling.

[0040] A small amount of exhaust steam from the low-pressure cylinder enters the condenser mist water supply unit 2, then flows through the low-pressure cylinder exhaust extraction pipe 8, the low-pressure cylinder exhaust extraction valve 9, and the deaerator heating steam pipe 10 into the internal steam distribution pipe 104. Finally, it is discharged into the outer shell of the vacuum pre-deaerator 1 through the steam outlet 105. Because the temperature of this portion of the low-pressure cylinder exhaust steam is slightly higher than the temperature cooled by the condenser, the exhaust steam flashes and releases latent heat inside the vacuum pre-deaerator 1. The saturated steam rises, while the saturated water falls to the bottom.

[0041] The deaerated water that needs to be pre-deoxygenated is atomized by the high-flow-rate deaerated water nozzle 102 and sprayed upwards, then falls downwards into the bottom of the vacuum pre-deaerator 1. During this process, it absorbs the latent heat released by the exhaust steam and also mixes and exchanges heat with the saturated steam. Both the atomization process and the heat exchange process release oxygen and other non-condensable gases, while simultaneously heating up and condensing more low-pressure cylinder exhaust steam.

[0042] The water that finally falls to the bottom of the vacuum pre-deaerator 1 enters the fine mist water supply nozzle structure through the deaerator drain pipe 5, the condenser water supply atomizing pump 6, and the water supply inlet pipe 7. Under the action of differential pressure, it is sprayed into the throat of the condenser through the fine mist water supply nozzle structure. This atomized water cools the exhaust steam from the low-pressure cylinder and moves towards the first cooling pipe at the condenser inlet, ultimately completing deep deaeration and heating to the saturation temperature under the condenser pressure.

[0043] Inside the vacuum pre-deaerator 1, the uncondensed saturated steam from the low-pressure cylinder exhaust, along with most of the oxygen and non-condensable gases released from the demineralized water, rises and flows upwards through the demister 108, the deaerator exhaust pipe 11, and the deaerator exhaust valve 13, directly into the condenser vacuum pump inlet, and is then discharged by the condenser vacuum pump. The deaerator vacuum gauge 12 is used to measure the vacuum value within the deaerator exhaust pipe 11.

[0044] In this embodiment, several layers of baffles 106 are provided on the inner wall surrounding the main body of the outer shell from top to bottom. Some atomized water or steam condensate may exist on the inner wall of the main body of the vacuum pre-deaerator 1. After flowing along the inner wall to each layer of baffles 106, it falls vertically to the bottom from the outer edge of the baffles 106.

[0045] In this embodiment, a level gauge 103 is provided on the outside of the outer casing, and the probe of the level gauge 103 extends into the outer casing. The level gauge 103 is used to measure the liquid level inside the vacuum pre-deaerator 1.

[0046] In this embodiment, a manhole 107 is provided on the upper outer side of the outer shell body.

[0047] In this embodiment, the vacuum pre-deaerator 1 is installed vertically.

[0048] In this embodiment, the outer shell of the vacuum pre-deaerator 1, the deaerator water inlet pipe 3, the deaerator drain pipe 5, the water replenisher inlet pipe 7, the low cylinder exhaust steam extraction pipe 8, the deaerator heating steam pipe 10, the deaerator exhaust pipe 11, the internal water inlet pipe 101, and the internal steam distribution pipe 104 are all made of stainless steel.

[0049] In this embodiment, the fine mist water supply nozzle structure comprises three layers, each layer including a diversion pipe and several downward-facing fine mist water supply nozzles. The fine mist water supply nozzles are evenly arranged on the diversion pipe and connected to it. The diversion pipes of each layer are interconnected at the same end on the same side and connected to the water supply inlet pipe 7. The water that finally falls to the bottom of the vacuum pre-deaerator 1 enters the fine mist water supply nozzle structure through the deaerator drain pipe 5, the condenser water supply atomizing pump 6, and the water supply inlet pipe 7 in sequence. It is then diverted to each layer of the fine mist water supply nozzle structure and sprayed into the throat of the condenser through the fine mist water supply nozzles of each layer.

[0050] More specifically, the bottom of the fine mist water supply nozzle located in the middle layer is 2000mm away from the first cooling pipe at the condenser inlet, and the bottom of the fine mist water supply nozzle located in the top layer and the fine mist water supply nozzle located in the bottom layer are 2200mm and 1800mm away from the first cooling pipe at the condenser inlet, respectively.

[0051] More specifically, in this embodiment, the fine mist water supply nozzle is a stainless steel 90° spiral nozzle.

[0052] In this embodiment, by adjusting the opening of the low-cylinder exhaust valve 9 and the deaerator exhaust valve 13, the vacuum value of the deaerator vacuum gauge 12 is adjusted to be slightly higher than the vacuum value of the condenser.

[0053] In this embodiment, the amount of demineralized water to be added and the spray pressure of the high-flow-rate demineralized water nozzle 102 are adjusted by adjusting the deaerator inlet pump 4.

[0054] In this embodiment, the liquid level of the vacuum pre-deaerator 1 and the spray pressure of the fine mist water supply nozzle structure are adjusted by regulating the condenser water supply atomizing pump 6.

[0055] Example 2

[0056] A thermal power plant originally consisted of 2×330MW water-cooled condensing units, which underwent heating and steam supply system upgrades. Before the upgrade, the unit makeup water rate was <1.5%, with an average makeup water volume of 15t / h per unit per hour. After the heating system was upgraded, due to water quality issues, this increased to 17t / h per month. The industrial steam supply system was designed to supply 200t / h of steam, but currently only 120t / h is supplied externally, and condensate is not recycled. Based on this, the total makeup water volume for the plant is calculated as 120 + 17 × 2 = 154.

[0057] The plant's original makeup water was located at the condenser throat, using a pipe-drilling method to spray demineralized water into the condenser. The actual latent heat absorption was essentially zero. According to plant statistics: the average temperature of the demineralized water was 18℃, and the average temperature of the condenser water was 41.5℃.

[0058] After adopting the water replenishment system described in Example 1, which enables non-powered vacuum pre-deoxygenation, the maximum designed water replenishment capacity of a single unit is 150 t / h. The current actual maximum water replenishment capacity of a single unit is 120 + 17 = 137 t / h, and the average water replenishment capacity is 154 / 2 = 77 t / h.

[0059] Economic benefits of reducing condensate supercooling:

[0060] Based on a capacity of 137 t / h: at 41.5℃, the enthalpy of saturated steam is 2576.24 kJ / kg, and the enthalpy of saturated water is 173.85 kJ / kg; at atmospheric pressure (18℃), the enthalpy of water is 71.45 kJ / kg. When the temperature of the 137 t / h demineralized water increases from 18℃ to 41.5℃, it can absorb heat.

[0061] 137×(173.85-71.45)=14.03GJ / h

[0062] Annual coal savings: 14.03 × 8000 h / a × 37 kg / GJ = 4152.5 t / a

[0063] Annual economic benefit: 4152.5t / a × 800 yuan / t = 3.32 million yuan

[0064] Economic benefits of reducing terminal differences and improving vacuum:

[0065] A single unit has a full-load steam flow rate of 1000 t / h, with approximately 750 t / h of steam ultimately reaching the low-pressure cylinder for exhaust. The condensable steam volume = 14.03 / (2576.24 - 173.85) = 5.84 t / h

[0066] As can be seen, the steam condensed by the water spray only accounts for 0.8% of the total steam volume theoretically, but due to pre-deoxygenation, its overall impact is significant. Furthermore, it is affected by factors such as winter and summer circulating water temperatures, condenser scaling conditions, and condenser leakage. Conservatively, the vacuum can be increased by 0.2 kPa in winter and >0.4 kPa in summer. Estimated annual revenue >400,000 yuan.

[0067] The economic benefits of reducing dissolved oxygen:

[0068] Pre-deoxygenation and deep deoxygenation reduce the amount of demineralized water added to within acceptable limits, thereby reducing oxygen corrosion in the condenser and low-pressure heater.

[0069] For those skilled in the art, various corresponding changes and modifications can be made based on the above technical solutions and concepts, and all such changes and modifications should be included within the protection scope of the claims of this invention.

Claims

1. A water replenishment system capable of achieving non-powered vacuum pre-deoxygenation, characterized in that, It includes a vacuum pre-deaerator (1), a condenser fine mist water supply device (2), a deaerator inlet water pipe (3), a deaerator inlet water pump (4), a deaerator drain pipe (5), a condenser water supply atomizing pump (6), a water supply device inlet pipe (7), a low cylinder exhaust steam extraction pipe (8), a low cylinder exhaust steam extraction valve (9), a deaerator heating steam pipe (10), a deaerator exhaust pipe (11), a deaerator vacuum gauge (12), and a deaerator exhaust valve (13); The vacuum pre-deaerator (1) includes a main body, inside which are provided an internal water inlet pipe (101), a high-flow demineralized water nozzle (102), an internal steam distribution pipe (104), a steam outlet (105), and a demister (108); the internal water inlet pipe (101) is connected to the high-flow demineralized water nozzle (102), which faces upward; the internal steam distribution pipe (104) is evenly provided with several upward-facing steam outlets (105), each of which is connected to the internal steam distribution pipe (104); the demister (108) is located on the inner top wall of the main body; The condenser mist water supply device (2) is connected to the low-pressure cylinder exhaust pipe, and has a fine mist water supply nozzle structure inside, which faces the condenser inlet; the deaerator inlet water pump (4) is connected to the inlet water internal pipe (101) through the deaerator inlet water pipe (3), and the deaerator drain pipe (5) is connected to the bottom of the outer shell of the vacuum pre-deaerator (1) and the inlet of the condenser water supply atomizing pump (6), respectively; the water supply device inlet pipe (7) is connected to the condenser water supply atomizing pump (6) respectively. The outlet and fine mist water supply nozzle structure of the condenser; the low cylinder exhaust steam extraction pipe (8) is connected to the upper part of the condenser fine mist water supply device (2) and the low cylinder exhaust steam extraction valve (9); the deaerator heating steam pipe (10) is connected to the low cylinder exhaust steam extraction valve (9) and the internal steam distribution pipe (104); the deaerator exhaust pipe (11) is connected to the top of the inner body of the vacuum pre-deaerator (1); the deaerator exhaust pipe (11) is equipped with a deaerator vacuum gauge (12) and a deaerator exhaust valve (13).

2. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, Several layers of water baffles (106) are provided around the inner wall of the outer shell body from top to bottom.

3. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, A level gauge (103) is provided on the outside of the outer casing, and the probe of the level gauge (103) extends into the outer casing.

4. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, A manhole (107) is provided on the upper outer side of the outer shell body.

5. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, The outer shell of the vacuum pre-deaerator (1), the deaerator water inlet pipe (3), the deaerator drain pipe (5), the water replenisher inlet pipe (7), the low cylinder exhaust steam extraction pipe (8), the deaerator heating steam pipe (10), the deaerator exhaust pipe (11), the internal water inlet pipe (101), and the internal steam distribution pipe (104) are all made of stainless steel.

6. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, The fine mist water supply nozzle structure includes three layers, each layer including a diversion pipe and several downward-facing fine mist water supply nozzles. The fine mist water supply nozzles are evenly arranged on the diversion pipe and connected to the diversion pipe. The diversion pipes of each layer are connected to each other at the same end on the same side and connected to the water supply inlet pipe (7).

7. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 6, characterized in that, The fine mist water supply nozzle uses a stainless steel 90° spiral nozzle.

8. The water replenishment system capable of achieving non-powered vacuum pre-deoxygenation according to claim 1, characterized in that, The flow rate of the demineralized water high-flow nozzle (102) is 200t / h.

9. A method of operating the system according to any one of claims 1-8, characterized in that, The specific process is as follows: The deoxygenated water that needs to be pre-deoxygenated enters the internal inlet pipe (101) through the deaerator inlet pump (4) and the deaerator inlet pipe (3). The atomized water is sprayed upward through the deoxygenated water high-flow nozzle (102), and after rising and falling, it accumulates at the bottom of the vacuum pre-deaerator (1). A small amount of exhaust steam from the low-pressure cylinder of the unit enters the fine mist water supply device (2) of the condenser and then enters the internal steam distribution pipe (104) through the low-pressure cylinder exhaust steam extraction pipe (8), the low-pressure cylinder exhaust steam extraction valve (9), and the deaerator heating steam pipe (10). It is then discharged into the outer shell of the vacuum pre-deaerator (1) through the steam outlet (105). Since the temperature of this part of the low-pressure cylinder exhaust steam is slightly higher than the temperature cooled by the condenser later, the exhaust steam flashes and releases latent heat inside the vacuum pre-deaerator (1). The saturated steam moves upward and the saturated water falls to the bottom. The deoxygenated water that needs to be pre-deoxygenated is atomized by the deoxygenated water high-flow nozzle (102) and sprayed upwards, and then falls downwards into the bottom of the vacuum pre-deoxygenator (1). During this process, it absorbs the latent heat released by the exhaust steam and also mixes and exchanges heat with the saturated steam. Both the atomization process and the heat exchange process will release oxygen and other non-condensable gases, while heating up and condensing more low-pressure cylinder exhaust steam. The water that finally falls to the bottom of the vacuum pre-deaerator (1) enters the fine mist water supply nozzle structure through the deaerator drain pipe (5), the condenser water supply atomizing pump (6), and the water supply inlet pipe (7) in sequence. Under the action of differential pressure, it is sprayed into the throat of the condenser through the fine mist water supply nozzle structure. This part of the atomized water will cool the exhaust steam of the low-pressure cylinder and move towards the first cooling pipe at the condenser inlet, finally completing the deep deaeration and heating to the saturation temperature under the condenser pressure. Inside the vacuum pre-deaerator (1), the uncondensed saturated steam from the low-pressure cylinder exhaust and most of the oxygen and non-condensable gases released from the demineralized water move upwards and pass through the demister (108), the deaerator exhaust pipe (11), and the deaerator exhaust valve (13) to directly enter the condenser vacuum pump inlet and be discharged by the condenser vacuum pump; the deaerator vacuum gauge (12) is used to measure the vacuum value inside the deaerator exhaust pipe (11).

10. The working method according to claim 9, characterized in that, By adjusting the opening of the low-cylinder exhaust valve (9) and the deaerator exhaust valve (13), the vacuum value of the deaerator vacuum gauge (12) is adjusted to be slightly higher than the vacuum value of the condenser; by adjusting the deaerator inlet pump (4), the amount of demineralized water to be added and the spray pressure of the demineralized water high-flow nozzle (102) are adjusted; by adjusting the condenser water atomizing pump (6), the liquid level of the vacuum pre-deaerator (1) and the spray pressure of the fine mist water nozzle structure are adjusted.

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