Method for improving hydrogen purity of generator and sealing oil system

Abstract

The invention discloses a method for improving the hydrogen purity of a generator and a sealing oil system, and relates to the technical field of generators, the method comprises the following steps: A, controlling the moisture content of sealing oil, and filtering moisture in the sealing oil through an efficient dehydration filter; b, removing water in the sealing oil, and separating the water in the sealing oil by reducing the pressure value in the vacuum oil tank; c, air in the sealing oil is removed, the air in the sealing oil is separated by reducing the pressure value in the vacuum oil tank, and a vacuum pump is adopted to extract the air from water vapor; and D, circularly purifying the sealing oil, wherein part of the sealing oil flows into the vacuum oil tank through a second nozzle device at the tail end of the circular oil supply pipeline to realize circular purification of the sealing oil. Water and gas in the sealing oil are separated by reducing the pressure value in the vacuum oil tank and are pumped away through the vacuum pump, so that air and residual water in the sealing oil can be effectively removed, and the purity of hydrogen of the generator is improved.

Description

Technical Field

[0001] The present application relates to the technical field of generators, and more specifically, to a method for improving the hydrogen purity of generators and a sealing oil system. Background Art

[0002] Hydrogen has the advantages of good thermal conductivity, low specific gravity, and high cooling efficiency, and is widely used in the cooling system of generators in power generation companies. However, hydrogen also has the disadvantages of strong permeability, easy leakage, and easy explosion and fire accidents when mixed with air.

[0003] In order to prevent the hydrogen of the generator from leaking out along the gap between the rotating shaft and the sealing shoe, and also to prevent the oil pressure from being too high and causing a large amount of oil to enter the generator, the generator adopts a sealing oil system, which provides lubricating oil to the generator sealing shoe to prevent the atmosphere and the gas in the sealing oil from contaminating the hydrogen in the generator.

[0004] Generator sealing pads are generally divided into single-flow ring sealing pads and double-flow ring sealing pads. The oil supply system of single-flow ring sealing pads has no independent oil source and needs to be provided by the turbine lubricating oil system. The lubricating oil system comes into contact with air during operation, and air and moisture will be dissolved in this process and form a saturated state under atmospheric pressure. The lubricating oil with these contents of air and moisture is sent to the sealing oil system to form sealing oil. If the sealing oil is not purified and the moisture is not removed before entering the sealing pad, it will be mixed with the hydrogen in the generator at the sealing pad. Because the sealing oil pressure is higher than the hydrogen pressure in the generator, the sealing oil pressure decreases during mixing, and the gas and moisture in the sealing oil will be released and contaminate the hydrogen in the generator, resulting in an increase in the rate of decrease in the purity of the hydrogen inside the generator. In order to maintain the purity of the hydrogen inside the generator, frequent hydrogen discharge and hydrogen replenishment operations are required, which is more harmful to the operation of the generator set.

[0005] Therefore, how to efficiently remove moisture and gas from the sealing oil and improve the purity of hydrogen in the generator has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] In view of this, the purpose of the present application is to provide a method for improving the purity of hydrogen in a generator, so as to efficiently remove moisture and gas in the sealing oil and improve the purity of hydrogen in the generator.

[0007] Another object of the present application is to provide a sealing oil system that adopts the above method for improving the hydrogen purity of the generator.

[0008] To achieve the above objectives, this application provides the following technical solutions:

[0009] A method for improving the purity of hydrogen in a generator, comprising:

[0010] Step A, controlling the moisture content of the sealing oil, filtering the moisture in the sealing oil flowing out of the lubrication box of the steam turbine through a high-efficiency dehydration filter, and flowing the moisture into the vacuum oil tank of the sealing oil purification device through a first nozzle device at the end of the oil supply pipeline, wherein the first nozzle device comprises a plurality of first nozzles distributed along the length direction of the vacuum oil tank, the first nozzle is a spiral nozzle, so that the sealing oil is sprayed in an umbrella shape, and the diameter of the droplets sprayed by the first nozzle is 0.5 mm to 0.8 mm;

[0011] Step B, removing moisture from the sealing oil by reducing the pressure in the vacuum oil tank to less than a first preset value, so that the moisture in the sealing oil is converted from liquid to vapor and separated from the sealing oil;

[0012] Step C, removing air and water vapor from the sealing oil, by reducing the pressure value in the vacuum oil tank to a second preset value to separate the air from the sealing oil, and using a vacuum pump connected to the vacuum oil tank to extract the air and water vapor;

[0013] Step D, circulates and purifies the sealing oil. After the sealing oil in the vacuum oil tank flows out through the discharge pipeline, part of the sealing oil flows into the vacuum oil tank through the second nozzle device at the end of the circulating oil supply pipeline, and repeats steps B and C. The second nozzle device includes a plurality of second nozzles distributed along the length direction of the vacuum oil tank. The second nozzle is a spiral nozzle, so that the sealing oil is sprayed in an umbrella shape, and the diameter of the droplets sprayed by the second nozzle is 0.5mm to 0.8mm.

[0014] Optionally, in the above method for improving the hydrogen purity of a generator, in the step of controlling the moisture content of the sealing oil, the step further includes: determining the number of first nozzles;

[0015] Determining the number of first nozzles specifically includes:

[0016] Step A1, determine the flow rate of a single first nozzle under the actual working differential pressure, according to the formula Q1 is obtained by calculation, wherein Q1 is the flow rate under the actual working differential pressure of the single first nozzle, ΔP1 is the actual working differential pressure of the single first nozzle, Q2 is the flow rate under the measured differential pressure of the single first nozzle, and ΔP2 is the measured working differential pressure of the single first nozzle;

[0017] Step A2, determining the number of first nozzles, and obtaining the number of first nozzles according to the ratio between the oil supply flow rate and the flow rate under the actual working differential pressure of a single first nozzle.

[0018] Optionally, in the above method for improving the hydrogen purity of a generator, in the step of circulating and purifying the sealing oil, the step further includes: determining the number of second nozzles;

[0019] Determining the number of second nozzles specifically includes:

[0020] Step D1, determine the flow rate of a single second nozzle under the actual working differential pressure, according to the formula Q3 is obtained by calculation, wherein Q3 is the flow rate under the actual working differential pressure of the single second nozzle, ΔP3 is the actual working differential pressure of the single second nozzle, Q4 is the flow rate under the measured differential pressure of the single second nozzle, and ΔP4 is the measured working differential pressure of the single second nozzle;

[0021] Step D2, determining the number of the second nozzles, and obtaining the number of the second nozzles according to the ratio between the circulation flow rate and the flow rate under the actual working differential pressure of a single second nozzle.

[0022] Optionally, in the above method for improving the hydrogen purity of a generator, each of the first nozzles is symmetrically arranged in two rows along the circumferential direction of the oil supply pipeline, and the angle between the center line of each of the first nozzles and the horizontal plane is 32°.

[0023] Optionally, in the above-mentioned method for improving the hydrogen purity of the generator, each of the second nozzles is arranged in four rows along the circumferential direction of the oil supply pipeline, and each of the second nozzles is alternately arranged along the length direction of the vacuum oil tank, and the angle between the center line of each second nozzle and the horizontal plane is 32°.

[0024] Optionally, in the above method for improving the hydrogen purity of a generator, in the step of controlling the moisture content of the sealing oil, the moisture content of the sealing oil after filtering through the high-efficiency dehydration filter does not exceed 100 mg / L.

[0025] Optionally, in the above method for improving the hydrogen purity of a generator, in the step of removing moisture from the sealing oil, the first preset value is no more than 9 kPa.a.

[0026] Optionally, in the above method for improving the hydrogen purity of a generator, in the step of removing sealing oil air and water vapor, the second preset value is 3.4 kPa.a to 6.7 kPa.a.

[0027] A sealing oil system adopts the method for improving the hydrogen purity of a generator as described in any of the above items, the sealing oil system includes a turbine lubrication box and a sealing oil purification device connected to the turbine lubrication box, the sealing oil purification device includes a vacuum oil tank and a vacuum pump located above the vacuum oil tank, and a separator is provided on the connecting pipeline between the vacuum pump and the vacuum oil tank.

[0028] Optionally, in the above-mentioned sealing oil system, the vacuum oil tank is connected to a discharge pipeline and a circulating oil supply pipeline, the discharge pipeline is provided with a sealing oil pump, the sealing oil pump is a volumetric oil pump, and an overflow valve is provided at the outlet of the sealing oil pump, and the circulating oil supply pipeline is connected to the overflow valve.

[0029] The method for improving the purity of hydrogen in the generator provided by the present application first filters the water in the sealing oil flowing out of the lubrication box of the steam turbine through a high-efficiency dehydration filter, and flows into the vacuum oil tank of the sealing oil purification device through the first nozzle device at the end of the oil supply pipeline; then, by reducing the pressure value in the vacuum oil tank to less than the first preset value, the water in the sealing oil is converted from liquid to vapor and separated from the sealing oil; then, by reducing the pressure value in the vacuum oil tank to the second preset value, the air is separated from the sealing oil, and the air and water vapor are extracted by a vacuum pump connected to the vacuum oil tank. In addition, after the sealing oil in the vacuum oil tank flows out through the discharge pipeline, part of the sealing oil flows into the vacuum oil tank through the second nozzle device at the end of the circulating oil supply pipeline to realize the circulation purification of the sealing oil. It can be seen from the above examples that the method for improving the purity of hydrogen in the generator provided by the present application, by reducing the pressure value in the vacuum oil tank, the water and gas in the sealing oil are separated, and it is extracted by the vacuum pump, so that the air and residual water in the sealing oil can be effectively removed. At the same time, part of the sealing oil discharged from the vacuum oil tank can flow into the vacuum oil tank again through the second nozzle device at the end of the circulating oil supply pipeline to realize the circulation purification of the sealing oil, which can further purify the sealing oil, reduce the risk of gas and moisture in the sealing oil contaminating the hydrogen in the generator, and improve the purity of the hydrogen in the generator, thereby ensuring the safe and stable operation of the generator. In addition, the first nozzle and the second nozzle use spiral nozzles, so that the oil is sprayed in an umbrella shape to ensure that the diameter of the droplets is between 0.5mm and 0.8mm, which can prevent the droplets from being directly extracted by the vacuum pump. At the same time, the area of ​​the sealing oil in the separation space of the vacuum oil tank can be increased, so that the gas in the sealing oil can be separated to the maximum extent per unit area, while ensuring the purification effect of the sealing oil, the purification efficiency of the sealing oil is improved.

[0030] The technical features mentioned above, the technical features to be mentioned below, and the technical features shown separately in the drawings can be combined with each other arbitrarily, as long as the combined technical features are not contradictory. All feasible feature combinations are technical contents clearly recorded in this article. Any of the multiple sub-features contained in the same sentence can be applied independently, and does not have to be applied together with other sub-features. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a process for improving the hydrogen purity of a generator provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of a lubricating oil treatment system provided in an embodiment of the present application;

[0034] Figure 3 A graph showing the dissolution of air in sealing oil provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram of the arrangement of the vacuum oil tank provided in the embodiment of the present application;

[0036] Figure 5 A schematic diagram of the structure of the spiral nozzle provided in the embodiment of the present application;

[0037] Figure 6 A schematic diagram of the spray angle of the spiral nozzle provided in the embodiment of the present application;

[0038] Figure 7 A side view of a first nozzle arrangement provided in an embodiment of the present application;

[0039] Figure 8 A top view of a first nozzle arrangement provided in an embodiment of the present application;

[0040] Fig. 9 Provided in the embodiments of this application Figure 7 AA section view in;

[0041] Fig.10 A side view of a second nozzle arrangement provided in an embodiment of the present application;

[0042] Fig.11 A top view of the second nozzle arrangement provided in an embodiment of the present application;

[0043] Fig.12 Provided in the embodiments of this application Fig.10 Middle BB section;

[0044] Fig.13 Provided in the embodiments of this application Fig.10 Middle CC section.

[0045] Among them, 100 is a steam turbine lubrication box, and 101 is a high-efficiency dehydration filter;

[0046] 200 is a vacuum oil tank, 201 is an oil supply pipeline, 202 is a first nozzle device, 2021 is a first nozzle, 203 is a discharge pipeline, 204 is a circulating oil supply pipeline, 205 is a second nozzle device, 2051 is a second nozzle, 206 is a vacuum pump, 207 is a separator, 208 is a sealing oil pump, 209 is an overflow valve, 210 is an isolation valve, and 211 is a solenoid valve. DETAILED DESCRIPTION

[0047] The core of this application is to provide a method for improving the purity of hydrogen in a generator, so as to efficiently remove moisture and gas in the sealing oil and improve the purity of hydrogen in the generator.

[0048] Another core of the present application is to provide a sealing oil system that adopts the above method for improving the hydrogen purity of the generator.

[0049] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0050] In order to maintain the purity of hydrogen inside the generator, it is necessary to frequently discharge and replenish hydrogen, which is very harmful to the operation of the generator set. First, it will cause energy waste. The generator set needs to frequently discharge and purify hydrogen. It is necessary to discharge part of the contaminated hydrogen inside the generator and then replenish hydrogen with higher purity, resulting in partial waste of hydrogen each time it is purified. Secondly, it will increase the risk of personnel misoperation. Frequent generator hydrogen purification operations may cause personnel misoperation, threatening the safe and stable operation of the generator. Furthermore, the purity of hydrogen directly affects the friction loss and wind friction loss of the generator. The decrease in hydrogen purity will cause a significant increase in the ventilation loss and rotor friction loss of the generator, thereby affecting the efficiency of the generator, and at the same time causing the insulation of the generator winding to decrease, seriously threatening the safety of the generator. In addition, hydrogen is a highly explosive dangerous good. During the operation of the generator, stator and rotor discharge may occur. When the purity of hydrogen decreases, there will be a risk of hydrogen explosion. In addition, in the process of hydrogen purification, it is easy to cause equipment failure or hydrogen leakage, thereby causing safety accidents such as shutdown or explosion of the generator set.

[0051] For this reason, Figure 1As shown, the embodiment of the present application discloses a method for improving the purity of hydrogen in a generator, including step S100 of controlling the moisture content of the sealing oil, step S200 of removing the moisture in the sealing oil, step S300 of removing the air and water vapor in the sealing oil, and step S400 of circulating and purifying the sealing oil. By reducing the pressure value in the vacuum oil tank 200, the moisture and gas in the sealing oil are separated, and the gas is extracted by the vacuum pump 206, so that the air and residual moisture in the sealing oil can be effectively removed. At the same time, the sealing oil partially discharged from the vacuum oil tank 200 can flow into the vacuum oil tank 200 again through the second nozzle device 205 at the end of the circulating oil supply pipeline 204 to realize the circulating purification of the sealing oil, which can further purify the sealing oil, reduce the risk of gas and moisture in the sealing oil contaminating the hydrogen in the generator, and improve the purity of the hydrogen in the generator, thereby ensuring the safe and stable operation of the generator. In addition, the first nozzle 2021 and the second nozzle 2051 can spray the oil in an umbrella shape by adopting a spiral nozzle, and can ensure that the diameter of the droplets is 0.5mm~0.8mm to prevent the droplets from being directly extracted by the vacuum pump 206. At the same time, the area of ​​the sealing oil separation space in the vacuum oil tank 200 can be increased, so that the gas in the sealing oil can be separated to the maximum extent per unit area, thereby improving the purification efficiency of the sealing oil while ensuring the purification effect of the sealing oil.

[0052] The following will be combined Figures 1 to 13 Taking a single flow ring sealing shoe and a sealing oil control system as an example, the method for improving the hydrogen purity of a generator disclosed in an embodiment of the present application is specifically explained and illustrated.

[0053] Step S100, controlling the moisture content of the sealing oil;

[0054] like Figure 2 and Figure 4 As shown, the water content in the sealing oil flowing out of the turbine lubrication box 100 is filtered through the high-efficiency dehydration filter 101, and flows into the vacuum oil tank 200 of the sealing oil purification device through the first nozzle device 202 at the end of the oil supply pipeline 201. The first nozzle device 202 may include a plurality of first nozzles 2021 distributed along the length direction of the vacuum oil tank 200. Specifically, since the sealing oil of the single-flow ring sealing shoe has no independent oil source, it needs to be supplied by the lubricating oil of the turbine lubrication box 100. In order to control the water content in the supplied sealing oil, a lubricating oil purification treatment system is provided in the sealing oil system. The purification treatment system keeps running continuously. The sealing oil is heated by a heater, and then passes through the high-efficiency dehydration filter 101. The particles, emulsified water and free water in the sealing oil can be effectively removed, and then the oil is sent back to the turbine lubrication box 100 by a pressure pump. Figure 2 As shown, the oil finally flows into the vacuum oil tank 200 of the sealing oil purification device through the multiple first nozzles 2021 of the first nozzle device 202 at the end of the oil supply pipeline 201, as shown in FIG. Figure 4As shown, to ensure that the moisture content in the sealing oil supplied to the generator is not higher than 100 mg / L. In the actual operation process, through sampling and analysis of the moisture content in the steam turbine lubrication box 100, it can be seen that the moisture content in the sealing oil of the generator can be controlled to be no higher than 50 mg / L. The specific sampling results are shown in Table 1.

[0055] Table 1 Sampling and analysis results of water content in the lubricating oil main tank

[0056]

[0057] Step S200, removing moisture from the sealing oil;

[0058] By reducing the pressure value in the vacuum oil tank 200 to less than the first preset value, the moisture in the sealing oil is converted from liquid to vapor and separated from the sealing oil, wherein the first preset value can be no more than 9kpa.a. Specifically, under atmospheric pressure, the boiling point of water is 100°C, and as the air pressure decreases, the boiling point of water will gradually decrease. Under vacuum, the boiling point of water can be reduced to a temperature below 100°C, and water will change from liquid to vapor. The sealing oil is supplied by the turbine lubricating oil tank 100, and the design requirement for the turbine lubricating oil temperature is 45°C. According to the water vapor saturation pressure table, as shown in Table 2, at a temperature of 45°C, the saturation pressure corresponds to 9.5837kpa. When the vacuum pressure of the vacuum oil tank 200 reaches 9.5837kpa.a, moisture begins to precipitate from the sealing oil in the form of water vapor. Therefore, when the oil temperature of the sealing oil is stabilized at 45°C and the vacuum pressure in the vacuum oil tank 200 is lower than 9kPa.a, the water in the sealing oil can be changed from liquid to vapor, thereby being separated from the sealing oil.

[0059] Table 2 Correspondence between saturated steam temperature and pressure

[0060]

[0061] Step S300, removing sealing oil, air and water vapor;

[0062] The air is separated from the sealing oil by reducing the pressure value in the vacuum oil tank 200 to a second preset value, and the air and the vapor-state water are extracted by a vacuum pump 206 connected to the vacuum oil tank 200. Specifically, it can be seen from step S100 that the water content of the sealing oil is controlled. In the sealing oil system of the single-flow ring sealing pad, the sealing oil is supplied by the steam turbine lubrication box 100. After the lubricating oil is pressurized by the booster pump in the steam turbine lubrication box 100, it is sent to each bearing of the steam turbine generator set through the steam turbine lubrication oil supply pipe. After completing the lubrication and cooling in the bearing, it returns to the bearing box. The bearing box is filled with air, so that a large amount of air and water will be dissolved in the lubricating oil. Figure 2As shown. In this process, the molecules of the gas will interact with the molecules of the liquid to form a dissolution equilibrium. The main components in the air are nitrogen and oxygen, and their solubility in the liquid is related to factors such as temperature, pressure and solute properties. In order to separate the gas in the sealing oil, the pressure value in the vacuum oil tank 200 is reduced to a second preset value, wherein the second preset value can be 3.4kPa.a~6.7kPa.a, so that the gas in the sealing oil can be separated, and then the gas and the vapor water separated from the moisture in the sealing oil in step S200 are extracted through the vacuum pump 206 connected to the vacuum oil tank 200, thereby achieving the purification effect of the sealing oil, as shown in FIG. Figure 4 shown.

[0063] It should be noted that the solubility of gas in sealing oil obeys Henry's law, such as Figure 3 As shown, the volume of gas dissolved in liquid at a certain temperature is proportional to the pressure, and the solubility δ is generally used to represent the degree of solubility. Among them:

[0064] , where Va is the volume of dissolved air and Vo is the volume of oil.

[0065] According to Henry's law, at a certain temperature, the lower the absolute pressure, the lower the air content of the liquid. Assuming that at pressure Po, the amount of air dissolved in a certain amount of oil is δo, when the pressure drops to P1, the amount of air dissolved in the oil is δ1, then △δ=δo-δ1, △δ is the supersaturation of air. If the pressure P1 is lower than a certain pressure Pg, the supersaturated air will be separated faster, and this pressure Pg is the air separation pressure.

[0066] In order to completely separate the gas dissolved in the sealing oil, the vacuum degree in the vacuum oil tank 200 is increased to separate more air from the sealing oil, and then the vacuum pump 206 located above the vacuum oil tank 200 is connected to the vacuum oil tank 200 through a pipeline to timely remove the gas separated from the vacuum oil tank 200. In order to ensure that the gas in the sealing oil can be separated to the greatest extent, and considering the suction efficiency of the vacuum pump 206, the resistance along the vacuum pipeline and other factors, the pressure value in the vacuum oil tank 200 is reduced to an absolute vacuum pressure of 3.4kpa.a to 6.7kpa.a, so that the gas content retained in the sealing oil is only 3% to 6.6% of the gas content under atmospheric pressure, thereby ensuring the oil purification effect of the sealing oil.

[0067] Step S400, circulating and purifying the sealing oil;

[0068] After the sealing oil in the vacuum oil tank 200 is purified and flows out through the discharge pipeline 203, part of the sealing oil flows into the vacuum oil tank 200 through the second nozzle device 205 at the end of the circulating oil supply pipeline 204, and repeats the above purification step S200 to remove the moisture in the sealing oil and step S300 to remove the air and water vapor in the sealing oil, thereby achieving the circulation purification effect of the sealing oil, wherein the second nozzle device 205 may include a plurality of second nozzles 2051 distributed along the length direction of the vacuum oil tank 200. Specifically, a sealing oil pump 208 is provided on the discharge pipeline 203, and a relief valve 209 is provided at the outlet of the sealing oil pump 208, and the circulating oil supply pipeline 204 is connected to the relief valve 209. In order to improve the sealing oil purification efficiency, the sealing oil pump 208 can adopt a positive displacement oil pump, so as to ensure the stable output of sealing oil of a certain capacity and pressure. The overflow valve 209 can be used to return the remaining sealing oil to the vacuum oil tank 200 while meeting the oil demand of the generator sealing pads. Liquid droplets are formed through the multiple second nozzles 2051 of the second nozzle device 205 at the end of the circulating oil supply pipeline 204, and the gas and water in the sealing oil are separated from the sealing oil under a high vacuum environment, thereby ensuring that the sealing oil in the vacuum oil tank 200 is continuously circulated for purification.

[0069] In some embodiments, in order to increase the area of ​​the sealing oil separation space in the vacuum oil tank 200, the gas in the sealing oil can be separated to the maximum extent per unit area. The first nozzle 2021 and the second nozzle 2051 can both adopt spiral nozzles, such as Figure 5 The sealing oil enters the vacuum oil tank 200 through the spiral nozzle, and the oil flow of the sealing oil can be formed into an "umbrella-shaped" state through the spiral nozzle, and a spiral shape is formed at a certain speed at the outlet of the spiral nozzle, so that the oil is sprayed in small droplets with a diameter of 0.5mm to 0.8mm, as shown in FIG. Figure 4 and Figure 6 As shown, the oil is prevented from being directly pumped out by the vacuum pump 206, and at the same time, the exposed area is increased under the high vacuum of the separation area in the vacuum oil tank 200, thereby improving the separation efficiency of the sealing oil.

[0070] It should be noted that in the above embodiments, droplets refer to the size of each spray droplet that constitutes the nozzle spray shape, and the size of all spray droplets is not consistent. The volume median diameter is usually used as a description method for spray droplets. The volume median diameter is the diameter of a droplet. In the total volume of the spray liquid, 50% is composed of droplets with a diameter greater than the median value, and the other 50% is composed of droplets with a diameter less than the median value. In each type of spray droplet, the minimum flow rate produces the finest spray droplets, and the maximum flow rate generates the coarsest spray droplets. In order to ensure that the gas in the sealing oil can be better separated, the number of atomizing nozzles will affect the separation effect. The sealing oil forms tiny oil droplets after passing through the nozzle and falls, and the gas in the tiny oil droplets will be separated under high vacuum. However, if the number of nozzles is small, the sealing oil after passing through the nozzle will be faster and fall with larger oil droplets, so that the air in the sealing oil cannot be separated in time. After falling below the sealing oil liquid surface, the air forms small bubbles, which will affect the gas separation effect.

[0071] In order to ensure the separation effect of the gas in the sealing oil, the step of controlling the moisture content of the sealing oil in step S100 also includes the step of determining the number of first nozzles. The step of determining the number of first nozzles specifically includes:

[0072] Step A1, determining the flow rate of a single first nozzle under actual working differential pressure;

[0073] According to the formula Q1 is calculated, where Q1 is the flow rate under the actual working differential pressure of the single first nozzle 2021 , ΔP1 is the actual working differential pressure of the single first nozzle 2021 , Q2 is the flow rate under the measured differential pressure of the single first nozzle 2021 , and ΔP2 is the measured working differential pressure of the single first nozzle 2021 .

[0074] Step A2, determining the number of first nozzles;

[0075] The number of the first nozzles 2021 is obtained according to the ratio between the oil supply flow rate and the flow rate of a single first nozzle 2021 under the actual working differential pressure.

[0076] In step S400 of circulating and purifying the sealing oil, a step of determining the number of second nozzles is also included. The step of determining the number of second nozzles specifically includes:

[0077] Step D1, determining the flow rate of a single second nozzle under actual working differential pressure;

[0078] According to the formula Q3 is calculated, where Q3 is the flow rate of the single second nozzle 2051 under the actual working differential pressure, ΔP3 is the actual working differential pressure of the single second nozzle 2051, Q4 is the flow rate under the measured differential pressure of the single second nozzle 2051, and ΔP4 is the measured working differential pressure of the single second nozzle 2051.

[0079] Step D2, determining the number of second nozzles;

[0080] The number of the second nozzles 2051 is obtained according to the ratio between the circulation flow rate and the flow rate of a single second nozzle 2051 under the actual working differential pressure.

[0081] In some embodiments, the sealing oil system is designed to meet the requirements for sealing oil flow in various states of the steam turbine generator set, that is, during the standby period of the generator set, the shaft speed of the generator set (cranking speed), the generator set during the start-up and speed-up period, and the various working conditions when the generator set reaches the rated speed. The actual working flow parameters of the sealing oil are shown in Table 3. The sealing oil pump 208 can adopt a screw positive displacement oil pump to ensure the stability of the output flow and has good self-priming ability. In the operation of the sealing oil system, the flow relationship of the sealing oil pump 208 is as follows: Q pump = Q circulation + Q supply, where Q pump is the flow of the sealing oil pump 208, Q circulation is the flow of the circulating oil supply pipeline, and Q supply is the flow of the oil supply pipeline. According to the flow test results of the spiral nozzle, when the inlet and outlet differential pressure of a single nozzle is 70kPa, the flow rate is 5.42 L / min.

[0082] Table 3 Actual working flow parameters of sealing oil

[0083]

[0084] In the step of determining the number of first nozzles, the measured working differential pressure ΔP2 of a single first nozzle 2021 is 70 kPa, and the flow rate Q2 under the measured differential pressure of a single first nozzle 2021 is 5.42 L / min. At the same time, the inlet pressure of the first nozzle 2021, i.e., the oil supply pressure of the oil supply pipeline, is 8 kPa to 250 kPa, and the outlet pressure of the first nozzle 2021, i.e., the pressure in the vacuum oil tank 200, is -95 kPa. Therefore, the actual working differential pressure ΔP1 of a single first nozzle 2021 is 250-(-95) = 345 kPa. According to the formula , the flow rate Q1 of a single first nozzle 2021 under the actual working differential pressure is calculated to be 12.03L / min. At the same time, the oil supply flow rate takes the maximum value of 200L / min, and the number of first nozzles 2021 is the ratio of the oil supply flow rate to the flow rate under the actual working differential pressure of a single first nozzle 2021, that is, 200 / 12.03=16.63≈17, and after fully considering the oil supply margin, the actual number of first nozzles 2021 that can be selected is 20.

[0085] In the step of determining the number of second nozzles, the measured working differential pressure ΔP4 of a single second nozzle 2051 is 70 kPa, and the flow rate Q4 under the measured differential pressure of a single second nozzle 2051 is 5.42 L / min. At the same time, the inlet pressure of the second nozzle 2051, i.e., the pressure after the overflow valve 209, is 0 kPa, and the outlet pressure of the second nozzle 2051, i.e., the pressure in the vacuum oil tank 200, is -95 kPa. Therefore, the actual working differential pressure ΔP3 of the single second nozzle 2051 is 0-(-95) = 95 kPa. According to the formula , the flow rate Q3 of the single second nozzle 2051 under the actual working differential pressure is calculated to be 6.31L / min. Since the function of the second nozzle 2051 is to return the sealing oil from the outlet of the sealing oil pump 208 to the vacuum oil tank 200, thereby removing the moisture and gas in the sealing oil, when selecting the flow rate of the circulating oil supply pipeline, the sealing oil flow rate before the generator set is started and during normal operation is taken into account. The sealing oil flow rate can be designed to be 120L / min, and the circulating oil flow rate during normal operation is 417-120=297L / min. Therefore, when the circulating oil flow rate takes a minimum value of 217L / min and a maximum value of 295L / min (297L / min is rounded up), the number of second nozzles 2051 when the circulating oil flow rate takes a minimum value of 217L / min is 217 / 6.31=34.38≈34.4, and the number of second nozzles 2051 when the circulating oil flow rate takes a maximum value of 295L / min is 295 / 6.31=46.8≈47. After considering the circulating oil flow margin in actual operation, the actual number of second nozzles 2051 that can be selected is 48.

[0086] In some embodiments, the capacity of the vacuum oil tank 200 may be 1.45 m 3 , and the inner diameter is 800mm, the length is 3010mm, during operation, it is necessary to ensure that the night position of the vacuum oil tank 200 is kept in the middle position, so that the separation space after the sealing oil passes through the first nozzle 2021 and the second nozzle 2051 is 400mm. Due to the limited height space of the vacuum oil tank 200, in order to make the first nozzle 2021 and the second nozzle 2051 evenly distributed in the vacuum oil tank 200, as shown in FIG. Figure 8 As shown, each first nozzle 2021 can be symmetrically arranged in two rows along the circumferential direction of the oil supply pipeline 201, and the angle α between the center line of each first nozzle 2021 and the horizontal plane is 32°, that is, the two rows of first nozzles 2021 are distributed in a "Y" shape, as shown in FIG. Figure 7 and Fig. 9 At the same time, Fig.10 and Fig.11As shown, the second nozzles 2051 are arranged in four rows along the circumferential direction of the oil supply pipeline 201, and the second nozzles 2051 are arranged alternately along the length direction of the vacuum oil tank 200. The angle between the center line of each second nozzle 2051 and the horizontal plane is 32°. Fig.12 and Fig.13 shown.

[0087] The method for improving the purity of hydrogen in the generator provided by the present application first filters the water in the sealing oil flowing out of the turbine lubrication box 100 through the high-efficiency dehydration filter 101, and flows into the vacuum oil tank 200 of the sealing oil purification device through the first nozzle device 202 at the end of the oil supply pipeline 201; then, by reducing the pressure value in the vacuum oil tank 200 to less than the first preset value, the water in the sealing oil is converted from liquid to vapor and separated from the sealing oil; then, by reducing the pressure value in the vacuum oil tank 200 to the second preset value, the air is separated from the sealing oil, and the vacuum pump 206 connected to the vacuum oil tank 200 is used to extract the air and water vapor. In addition, after the sealing oil in the vacuum oil tank 200 flows out through the discharge pipeline 203, part of the sealing oil flows into the vacuum oil tank 200 through the second nozzle device 205 at the end of the circulating oil supply pipeline 204, so as to realize the circulation purification of the sealing oil.

[0088] The method for improving the purity of hydrogen in the generator provided by the present application reduces the pressure value in the vacuum oil tank 200, so that the water and gas in the sealing oil are separated, and the water and gas are extracted by the vacuum pump 206, so that the air and residual water in the sealing oil can be effectively removed. At the same time, the sealing oil partially discharged from the vacuum oil tank 200 can flow into the vacuum oil tank 200 again through the second nozzle device 205 at the end of the circulating oil supply pipeline 204 to realize the circulation purification of the sealing oil, which can further purify the sealing oil, reduce the risk of gas and water in the sealing oil contaminating the hydrogen in the generator, and improve the purity of the hydrogen in the generator, thereby ensuring the safe and stable operation of the generator. In addition, by using the first nozzle 2021 and the second nozzle 2051 to send the sealing oil into the vacuum oil tank 200, the area of ​​the sealing oil in the separation space of the vacuum oil tank 200 can be increased, so that the gas in the sealing oil can be separated to the maximum extent per unit area, while ensuring the purification effect of the sealing oil, the purification efficiency of the sealing oil is improved.

[0089] The embodiment of the present application also discloses a sealing oil system, which adopts the method for improving the hydrogen purity of the generator disclosed in the above embodiment. Therefore, the sealing oil system has all the technical effects of the above-mentioned method for improving the hydrogen purity of the generator, which will not be repeated herein.

[0090] Among them, Figure 2 and Figure 4As shown, the sealing oil system may include a steam turbine lubrication box 100 and a sealing oil purification device connected to the steam turbine lubrication box 100, and the sealing oil purification device may include a vacuum oil tank 200 and a vacuum pump 206 located above the vacuum oil tank 200, and a separator 207 is provided on the connecting pipeline between the vacuum pump 206 and the vacuum oil tank 200, so that the sealing oil remaining in the extracted gas can be separated by the separator 207. It should be noted that, as Figure 4 As shown, a solenoid valve 211 is further provided at the inlet of the separator 207 , and an isolation valve 210 is provided at the outlet of the separator 207 .

[0091] In some embodiments, Figure 4 As shown, the vacuum oil tank 200 is also connected to a discharge pipeline 203 and a circulating oil supply pipeline 204. A sealing oil pump 208 is provided on the discharge pipeline 203. The sealing oil pump 208 can be a positive displacement oil pump, and a relief valve 209 is provided at the outlet of the sealing oil pump 208. The circulating oil supply pipeline 204 is connected to the relief valve 209. It should be noted that the technical effects of the sealing oil pump 208 using a positive displacement oil pump and the relief valve 209 being provided at the outlet of the sealing oil pump 208 have been explained and described above, and will not be repeated herein.

[0092] The terms "first" and "second" and the like in the specification and claims of this application and the above drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may include steps or units that are not listed.

[0093] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be 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 present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the purity of hydrogen in a generator, characterized in that: include: Step A, controlling the moisture content of the sealing oil, filtering the moisture in the sealing oil flowing out of the turbine lubrication box (100) through a high-efficiency dehydration filter (101), and flowing the moisture into the vacuum oil tank (200) of the sealing oil purification device through a first nozzle device (202) at the end of the oil supply pipeline (201), wherein the first nozzle device (202) comprises a plurality of first nozzles (2021) distributed along the length direction of the vacuum oil tank (200), the first nozzles (2021) being spiral nozzles, so that the sealing oil is sprayed in an umbrella shape, and the diameter of the droplets sprayed by the first nozzles (2021) is 0.5 mm to 0.8 mm; Step B, removing moisture from the sealing oil, by reducing the pressure value in the vacuum oil tank (200) to less than a first preset value, so that the moisture in the sealing oil is converted from liquid to vapor and separated from the sealing oil; Step C, removing air and water vapor from the sealing oil, by reducing the pressure value in the vacuum oil tank (200) to a second preset value so as to separate the air from the sealing oil, and using a vacuum pump (206) connected to the vacuum oil tank (200) to extract the air and water vapor; Step D, circulating and purifying the sealing oil, after the sealing oil in the vacuum oil tank (200) flows out through the discharge pipeline (203), part of the sealing oil flows into the vacuum oil tank (200) through the second nozzle device (205) at the end of the circulating oil supply pipeline (204), and repeating steps B and C, wherein the second nozzle device (205) includes a plurality of second nozzles (2051) distributed along the length direction of the vacuum oil tank (200), and the second nozzle (2051) is a spiral nozzle, so that the sealing oil is sprayed in an umbrella shape, and the diameter of the droplets sprayed by the second nozzle (2051) is 0.5 mm to 0.8 mm.

2. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: The step of controlling the moisture content of the sealing oil further includes the steps of: determining the number of first nozzles; Determining the first number of nozzles specifically includes: Step A1, determine the flow rate of a single first nozzle under the actual working differential pressure, according to the formula Q1 is obtained by calculation, wherein Q1 is the flow rate under the actual working differential pressure of the single first nozzle (2021), ΔP1 is the actual working differential pressure of the single first nozzle (2021), Q2 is the flow rate under the measured differential pressure of the single first nozzle (2021), and ΔP2 is the measured working differential pressure of the single first nozzle (2021); Step A2, determining the number of first nozzles, and obtaining the number of first nozzles (2021) based on the ratio between the oil supply flow rate and the flow rate under the actual working differential pressure of a single first nozzle (2021).

3. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: The step of circulating and purifying the sealing oil further includes the steps of: determining the number of second nozzles; Determining the number of second nozzles specifically includes: Step D1, determine the flow rate of a single second nozzle under the actual working differential pressure, according to the formula Q3 is obtained by calculation, wherein Q3 is the flow rate under the actual working differential pressure of the single second nozzle (2051), ΔP3 is the actual working differential pressure of the single second nozzle (2051), Q4 is the flow rate under the measured differential pressure of the single second nozzle (2051), and ΔP4 is the measured working differential pressure of the single second nozzle (2051); Step D2, determining the number of second nozzles, and obtaining the number of the second nozzles (2051) based on the ratio between the circulation flow rate and the flow rate under the actual working differential pressure of a single second nozzle (2051).

4. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: The first nozzles (2021) are symmetrically arranged in two rows along the circumferential direction of the oil supply pipeline (201), and the angle between the center line of each first nozzle (2021) and the horizontal plane is 32°.

5. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: The second nozzles (2051) are arranged in four rows along the circumferential direction of the oil supply pipeline (201), and the second nozzles (2051) are arranged alternately along the length direction of the vacuum oil tank (200), and the angle between the center line of each second nozzle (2051) and the horizontal plane is 32°.

6. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: In the step of controlling the moisture content of the sealing oil, the moisture content of the sealing oil after filtering through the high-efficiency dehydration filter (101) does not exceed 100 mg / L.

7. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: In the step of removing moisture from the sealing oil, the first preset value is no more than 9 kPa.a.

8. The method for improving the purity of hydrogen in a generator according to claim 1, characterized in that: In the step of removing air and water vapor from the sealing oil, the second preset value is 3.4 kPa.a to 6.7 kPa.a.

9. A sealing oil system, characterized in that: A method for improving the hydrogen purity of a generator as claimed in any one of claims 1 to 8 is adopted, wherein the sealing oil system comprises a turbine lubrication box (100) and a sealing oil purification device connected to the turbine lubrication box (100), the sealing oil purification device comprises a vacuum oil tank (200) and a vacuum pump (206) located above the vacuum oil tank (200), and a separator (207) is provided on the connecting pipeline between the vacuum pump (206) and the vacuum oil tank (200).

10. The sealing oil system according to claim 9, characterized in that: The vacuum oil tank (200) is connected to a discharge pipeline (203) and a circulating oil supply pipeline (204); the discharge pipeline (203) is provided with a sealing oil pump (208); the sealing oil pump (208) is a positive displacement oil pump; and an overflow valve (209) is provided at the outlet of the sealing oil pump (208); the circulating oil supply pipeline (204) is connected to the overflow valve (209).

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