A combined bubbling deoxygenation nozzle and a combined bubbling deoxygenation method

Abstract

This invention discloses a combined bubbling deaerator nozzle and a combined bubbling deaerator method. The combined bubbling deaerator nozzle includes an ejector nozzle connected to a mixing diffuser assembly, which includes at least two stages of mixing diffusers, with an injection nozzle positioned between the at least two stages. The method includes the following steps: S1, incoming high-temperature steam first mixes and heats the surrounding condensate with the incoming high-temperature steam in the first-stage mixing diffuser through the ejector nozzle; S2, utilizing the residual kinetic energy of the mixed liquid at the outlet of the previous stage mixing diffuser, the mixture is further mixed and heated in the next stage mixing diffuser through the injection nozzle; S3, the condensate, fully heated to saturation, is finally discharged. Deep deaeration of condensate can be achieved inside the condenser, replacing conventional thermal deaerators. After deep deaeration, the oxygen content of the condensate in the condenser can meet the oxygen content standards for power plant boiler feedwater.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and in particular to a combined bubbling deaerator nozzle and a combined bubbling deaerator method. Background Technology

[0002] For conventional steam turbine boiler feedwater, an independent deaerator is used for thermal deaeration. The basic principles of thermal deaeration are Henry's Law and Dalton's Law: for various gases dissolved in water, under a given pressure, the higher the water temperature, the lower the solubility. The thermal deaerator utilizes steam to heat the feedwater to its saturation temperature at a corresponding pressure. At this point, the steam partial pressure approaches the total pressure above the water surface, and the partial pressures of the various gases dissolved in the water approach zero. Under these conditions, the water loses its ability to dissolve gases, and the dissolved gases precipitate out. Deaerated water does not increase salinity or the amount of other dissolved gases.

[0003] The deaerator is positioned high up, and during normal unit operation, the steam used by the deaerator is drawn from the turbine interstage. Due to its high-positioning, the turbine is constantly exposed to a serious risk of water ingress, and its construction cost is also high. To reduce initial investment and operational risks, some power plants have proposed adopting a deaerator-free feedwater system for the entire plant. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems by providing a combined bubbling deaeration nozzle and a combined bubbling deaeration method built into the condenser, so that the oxygen content of the condensate in the feedwater system without a deaerator can meet the boiler feedwater standard.

[0005] The technical solution adopted in this invention is as follows:

[0006] A combined bubbling deaerator nozzle includes an ejector nozzle, the ejector nozzle being connected to a mixing diffuser assembly, the mixing diffuser assembly including at least two stages of mixing diffusers, and an injection nozzle being provided between the at least two stages of the mixing diffusers.

[0007] Alternatively, the mixing diffuser assembly may include a first-stage mixing diffuser, a jet nozzle, and a second-stage mixing diffuser arranged sequentially.

[0008] Alternatively, a condensate inlet can be connected to the inlet of the mixing diffuser.

[0009] Alternatively, the condensate inlet can be a sleeve with an inlet hole.

[0010] Alternatively, the water inlet hole may be arranged radially.

[0011] Alternatively, the water inlet may include multiple inlets, which are distributed circumferentially.

[0012] Alternatively, the mixing diffusion tube may include a tapered section, a straight section, and a diffusion section arranged sequentially.

[0013] A combined bubbling deoxygenation method includes the following steps:

[0014] S1. The incoming high-temperature steam first mixes and heats the surrounding condensate with the incoming high-temperature steam in the first-stage mixing and diffusion tube through the ejector nozzle.

[0015] S2. Utilize the residual kinetic energy of the mixed liquid at the outlet of the previous mixing and diffusion tube to remix and heat it in the next mixing and diffusion tube through the injection nozzle;

[0016] S3. The condensate that has been fully heated to saturation is finally discharged.

[0017] Alternatively, step S2 can be performed multiple times.

[0018] Alternatively, the ejector nozzle and the jet nozzle can generate a negative pressure when the fluid is injected at high speed into the mixing diffuser, and the condensate enters the mixing diffuser through the negative pressure generated.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. The combined bubbling deaerator nozzle and combined bubbling deaerator method disclosed in this invention can perform deep deaeration of condensate inside the condenser, replacing conventional thermal deaerators. After deep deaeration, the oxygen content of the condensate in the condenser can meet the oxygen content standard of power plant boiler feedwater.

[0021] 2. The combined bubbling deaeration nozzle and combined bubbling deaeration method disclosed in this invention can reduce the initial overall investment of power plants, reduce the subsequent use and maintenance costs, have broad market prospects, and have extremely high commercial promotion value. Attached Figure Description

[0022] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] The markings in the diagram are: 1-Ejector nozzle, 2-Sleeve, 21-Water inlet, 3-First-stage mixing diffuser, 4-Jet nozzle, 5-Second-stage mixing diffuser, 6-Converging section, 7-Straight section, 8-Diffuser section. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings.

[0026] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0027] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0028] A combined bubbling deaerator nozzle, such as Figure 1 As shown, it includes an ejector nozzle 1, which is connected to a mixing diffusion tube group. The mixing diffusion tube group includes at least two stages of mixing diffusion tubes, and an injection nozzle 4 is provided between the mixing diffusion tubes.

[0029] Specifically, existing devices generally use an ejector nozzle 1. The ejector nozzle 1 has a larger residual power at the outlet, resulting in a shorter mixing time compared to the nozzle of this patent. A large amount of steam overflows from the condensate without being fully mixed and is thus cooled by the condenser, failing to achieve the desired deoxygenation effect. The ejector nozzle 1 ejects external high-temperature steam, which then enters the mixing diffuser assembly to mix and heat the surrounding condensate. This device employs at least two stages of mixing diffusers, with injection nozzles 4 positioned between them. High-temperature steam first mixes and heats the surrounding condensate with the steam through the ejector nozzle 1. Then, utilizing the residual kinetic energy of the liquid mixture at the outlet of the mixing diffuser after the ejector nozzle 1, the liquid ejected at high speed through the injection nozzle 4 mixes and heats the surrounding condensate again. The condensate undergoes multiple mixing and heating processes with the high-temperature steam passing through the nozzles, thus extending the contact time between the steam and condensate, allowing sufficient time for energy transfer. Ultimately, the condensate in the condenser is fully heated to saturation, maximizing the precipitation of non-condensable gases and achieving a deep deoxygenation effect.

[0030] In another specific implementation, the mixing diffuser assembly includes a first-stage mixing diffuser 3, an injection nozzle 4, and a second-stage mixing diffuser 5 arranged sequentially. Existing methods only use an ejector for mixing and heating once; after a second mixing and heating, the residual power at the outlet after the first mixing and heating can be effectively utilized.

[0031] In another specific implementation, a condensate inlet is connected to the inlet of the mixing diffuser. By allowing condensate to enter the mixing diffuser directly from its inlet, it begins to be heated with high-temperature steam or a high-temperature liquid mixture, ensuring that the mixed water and steam are evenly distributed throughout. This maximizes the mixing of water and steam, resulting in better deoxygenation. Furthermore, when water and steam mix, oxygen in the water enters the mixing diffuser along with the steam. Due to turbulent resonance and diffusion, oxygen molecules disperse towards areas of lower concentration, thus being effectively removed.

[0032] In another specific implementation, the condensate inlet is a sleeve 2, which has an inlet hole 21. The sleeve 2 is designed for easy manufacturing, assembly, and maintenance, and facilitates adjustment of the inlet position and direction, allowing condensate to smoothly enter the mixing diffuser and reducing limitations on pipe layout. A certain gap is formed between the sleeve 2 and the inner wall of the mixing diffuser. When condensate enters the mixing diffuser from the sleeve 2, this gap maintains a certain water level. This design helps condensate enter the mixing diffuser more stably, reducing water level fluctuations and residual oxygen.

[0033] In another specific implementation, the water inlet 21 is arranged radially. Arranging the water inlet 21 radially allows the condensate to intersect in the fluid flow direction, increasing the probability of mixing and also increasing the speed of water vapor flow, thus promoting faster mixing and improving deoxygenation efficiency. Furthermore, arranging the water inlet 21 radially helps maintain a stable condensate level, preventing fluctuations and residual oxygen.

[0034] In another specific implementation, the water inlet 21 comprises multiple inlets distributed circumferentially. This allows for better and more even distribution of water within the equipment, improving water uniformity and contributing to stable operation and improved treatment efficiency. Furthermore, the flow rate is dispersed across multiple orifices, with relatively low water flow velocity at each orifice, thereby reducing pressure loss. Additionally, this reduces the risk of clogging at the water inlet 21, enhancing equipment stability and minimizing maintenance workload.

[0035] In another specific embodiment, the mixing diffuser includes a tapered section 6, a straight section 7, and a diffuser section 8 arranged sequentially. In the tapered section 6, the flow velocity increases accordingly, and as the steam velocity increases, heat transfer also increases. This causes oxygen molecules in the water to absorb more heat and evaporate or vaporize more quickly, thereby accelerating the removal of oxygen molecules. Then, after diffusing through the straight section 7, the vapor enters the injection nozzle 4 and is injected into the next stage of the mixing diffuser.

[0036] A combined bubbling deoxygenation method includes the following steps:

[0037] S1. The external high-temperature steam first mixes and heats the surrounding condensate with the external high-temperature steam in the first-stage mixing and diffusion tube 3 through the ejector nozzle 1.

[0038] S2. Utilize the residual kinetic energy of the mixed liquid at the outlet of the previous stage mixing diffuser to remix and heat it in the next stage mixing diffuser through the injection nozzle 4;

[0039] S3. The condensate that has been fully heated to saturation is finally discharged.

[0040] Specifically, in step S1, the ejector nozzle 1 uses high-energy steam to heat the condensate in the condenser to a saturated state, thereby precipitating oxygen from the condensate. High-temperature, high-pressure steam is used as the nozzle's power source, mixing and heating it through the ejector nozzle 1. Since the condensate is continuously generated, in step S2, the jet nozzle 4 uses the residual power of the mixed liquid at the outlet of the ejector nozzle 1 as the power source for the next stage of the jet nozzle 4. This increases the mixing contact time of the condensate, improves efficiency, and allows for efficient utilization of steam energy. This device uses ejector nozzle 1 to initially mix and heat the surrounding condensate with external high-temperature steam. Then, using the residual kinetic energy of the mixed liquid at the outlet of the mixing diffuser after ejector nozzle 1, the liquid ejected at high speed through nozzle 4 mixes and heats the surrounding condensate again. The condensate undergoes multiple mixing and heating processes with the high-temperature steam passing through the nozzle, thus increasing the contact time between the steam and condensate and allowing sufficient time for energy transfer. Ultimately, the condensate in the condenser is fully heated to saturation, allowing non-condensable gases to be released to the maximum extent, thereby achieving a deep deoxygenation effect.

[0041] As another specific implementation, step S2 can be performed multiple times. If the residual power at the second injection outlet is still large enough, a third mixing and heating can be performed until the steam energy is fully utilized.

[0042] In another specific implementation, the ejector nozzle 1 and the jet nozzle 4 generate negative pressure when they inject fluid at high speed into the mixing diffuser. Condensate then enters the mixing diffuser through this negative pressure. When the fluid is injected into the pipe from the nozzle, it forms a high-speed jet, which creates a low-pressure area around the nozzle. According to Bernoulli's principle, as the fluid velocity increases, its pressure decreases. The jet makes its pressure significantly lower than the surrounding environment pressure, thus creating a localized negative pressure. This, in turn, allows surrounding condensate to continuously enter the mixing diffuser through this negative pressure.

[0043] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0044] 1. The combined bubbling deaerator nozzle and combined bubbling deaerator method disclosed in this invention can perform deep deaeration of condensate inside the condenser, replacing conventional thermal deaerators. After deep deaeration, the oxygen content of the condensate in the condenser can meet the oxygen content standard of power plant boiler feedwater.

[0045] 2. The combined bubbling deaeration nozzle and combined bubbling deaeration method disclosed in this invention can reduce the initial overall investment of power plants, reduce the subsequent use and maintenance costs, have broad market prospects, and have extremely high commercial promotion value.

[0046] In the description of the embodiments of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "multiple" means two or more, unless otherwise explicitly specified.

[0047] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A combined bubbling deaerator nozzle, characterized in that: Built into the condenser, so that the condensate in the condenser can be completely heated to saturation; including an ejector nozzle (1), the ejector nozzle (1) is connected to a mixing diffuser assembly, the mixing diffuser assembly includes at least two stages of mixing diffusers, the mixing diffuser includes a tapered section (6), a straight section (7) and a diffuser section (8) arranged in sequence, and an injection nozzle (4) is provided between the at least two stages of the mixing diffusers; a condensate inlet is connected to the inlet of the mixing diffuser, the condensate inlet is a sleeve (2), and the sleeve (2) is provided with a water inlet hole (21).

2. The combined bubbling deaerator nozzle as described in claim 1, characterized in that: The mixing diffuser assembly includes a first-stage mixing diffuser (3), a jet nozzle (4), and a second-stage mixing diffuser (5) arranged sequentially.

3. The combined bubbling deaerator nozzle as described in claim 1, characterized in that: The water inlet (21) is arranged radially.

4. The combined bubbling deaerator nozzle as described in claim 1, characterized in that: The water inlet (21) includes multiple inlets, which are distributed circumferentially.

5. A combined bubbling deoxygenation method, using a deoxygenation nozzle as described in any one of claims 1-4, comprising the following steps: S1. The external high-temperature steam first mixes and heats the surrounding condensate and the external high-temperature steam in the first-stage mixing and diffusion tube (3) through the ejector nozzle (1); S2. Utilize the residual kinetic energy of the mixed liquid at the outlet of the previous mixing diffuser tube to remix and heat it in the next mixing diffuser tube through the injection nozzle (4); S3. The condensate that has been fully heated to saturation is finally discharged.

6. The combined bubbling deoxygenation method as described in claim 5, comprising the following steps: Step S2 can be performed multiple times.

7. The combined bubbling deoxygenation method as described in claim 5, comprising the following steps: When the ejector nozzle (1) and the jet nozzle (4) inject fluid into the mixing diffuser at high speed, a negative pressure is generated, and the condensate enters the mixing diffuser through the generated negative pressure.

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