Intermediate dehumidification two-way steam exhaust through-flow structure for high-parameter saturated steam

Abstract

A middle dehumidification two-way steam exhaust through-flow structure for high-parameter saturated steam is provided with a cylinder, a rotor shaft is assembled in the axial direction of the cylinder in the front-back direction, a front steam seal and a rear steam seal which are used for sealing are installed between the two ends of the rotor shaft and the cylinder, and the cylinder is divided into two independent cavities in the front-back direction. A plurality of left side blades assembled on the rotor shaft are arranged in the left side cavity, a plurality of right side blades assembled on the rotor shaft are arranged in the right side cavity, and a primary steam chamber and a secondary steam chamber which are arranged up and down are arranged between the left side cavity and the right side cavity. The two steam chambers are placed in the middle of the cylinder, so that the function of two-way steam exhaust is achieved, and the intermediate-stage external dehumidification effect is achieved. A primary steam exhaust port of a cylinder which is originally dehumidified in the middle is placed on a machine head, and a secondary steam inlet of the dehumidified cylinder is placed in the middle of the cylinder. Dehumidified steam expands to the tail to do work, dead steam is discharged to a condenser, and the sealing pressure at the two ends is reduced.

Description

Technical Field

[0001] The utility model relates to the field of steam turbines, especially to the field of power generation by using the waste heat of high-parameter saturated steam generated in the metallurgical and non-ferrous smelting processes. Specifically, it refers to an intermediate dehumidification and two-way exhaust flow structure for high-parameter saturated steam. Background Technique

[0002] In the processes of metal smelting projects such as metallurgy and non-ferrous metals, such as the converter steelmaking process in iron and steel production, and the bottom blowing reduction processes of gold, copper, lead, and zinc, etc., a large amount of waste heat resources of saturated steam above 4.0 MPa are generated. The most effective way to utilize this kind of waste heat resource is to enter a high-parameter saturated steam turbine to do work and generate electricity. The saturated steam above 4.0 MPa expands and does work in the pressure stage of the steam turbine, and the pressure and temperature decrease gradually, while the humidity increases gradually. When the pressure drops to about 0.8 MPa, the humidity will be > 0.11, and the water erosion, erosion, and corrosion characteristics of the internal parts of the steam turbine are enhanced, which directly affects the safe and stable operation of the steam turbine. Therefore, it is necessary to dehumidify the whole machine's flow path to ensure the steam dryness, which puts forward higher requirements for the design and operation of high-parameter saturated steam turbines.

[0003] To solve the problem of high humidity in the unit after the high-parameter saturated steam turbine does work, our company already has high-parameter saturated steam simple back-pressure units such as Figure 1 shown by the single unit on the left. The inlet steam pressure is 4.5 MPa. After expanding and doing work in the steam turbine, the pressure drops to about 0.8 MPa. At this time, the humidity is close to 0.11 and is discharged through the steam turbine exhaust port in time to provide heat source for enterprises or heating after pressure reduction. This kind of high-parameter saturated steam simple back-pressure unit is suitable for enterprises with less power generation and large heat demand. Our company also has a series operation system of a pure back-pressure plus condensing unit, such as Figure 1 shown. The operation mode of this system is that the high-parameter saturated steam above 4.5 MPa expands and does work in the pure back-pressure machine, and the pressure drops to about 0.8 MPa. It is discharged through the exhaust port of the back-pressure unit, dehumidified by a steam-water separator and then introduced into the subsequent condensing unit to continue expanding and doing work. The exhausted steam at about 100 KPa after doing work is discharged to the condenser. In this scheme, the two units are independently controlled, and the power generation or heating working condition can be switched according to the user's needs.

[0004] For pure power generation users without heating requirements, the above-mentioned Scheme 1 does not meet the requirements; although Scheme 2 can meet the requirements, the series operation of two steam turbine units has a high cost and is applicable to users with dual requirements for heating and power generation. And the function redundancy of realizing the switching operation, pure power generation users may not need this function, and the corresponding process system is also complex. Content of the Utility Model

[0005] To solve the above technical problems, the utility model provides an intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam. By placing the steam chamber in the middle part of the cylinder, the function of two-way exhaust is realized, and at the same time, the external dehumidification effect of the intermediate stage is achieved. The original primary exhaust port of the cylinder for intermediate dehumidification is placed at the head end, and the secondary steam inlet of the cylinder after dehumidification is placed at the middle position of the cylinder. The design is reasonable and the structure is compact. Compared with the series connection of two units, the cost can be significantly saved and the floor area can be reduced. Moreover, it can ensure the steam dryness of the whole machine, while reducing the steam seal leakage and axial thrust.

[0006] To achieve the above technical purpose, the technical solution adopted is: an intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam, which is provided with a cylinder. A rotor shaft is axially assembled in the cylinder in the front-back direction. Front steam seals and rear steam seals for sealing are installed between the two ends of the rotor shaft and the cylinder. The cylinder is divided into two independent chambers in the front-back direction, namely a left chamber and a right chamber. A plurality of left blades assembled on the rotor shaft are arranged in the left chamber, and a plurality of right blades assembled on the rotor shaft are arranged in the right chamber. The blades in the same chamber have the same rotation direction, and the blades in different chambers have opposite rotation directions. Pressure stage seals are carried out between the blades. An intermediate steam chamber and a secondary steam chamber are arranged between the left chamber and the right chamber. The intermediate steam chamber is communicated with the left chamber through a high-pressure exhaust port of the steam chamber for the first time, and the secondary steam chamber is communicated with the right chamber through a low-pressure exhaust port of the steam chamber for the second time. A primary steam inlet of the cylinder communicating with the intermediate steam chamber for steam inlet and a secondary steam inlet of the cylinder communicating with the secondary steam chamber for steam inlet are arranged in the middle of the cylinder. A primary exhaust port of the cylinder for exhausting steam communicating with the front end of the left chamber and a low-pressure exhaust port for exhausting exhausted steam communicating with the rear end of the right chamber are also arranged on the cylinder. A steam-water separator is connected between the primary exhaust port of the cylinder and the secondary steam inlet of the cylinder.

[0007] The intermediate steam chamber of the utility model is located at the middle position of the upper part of the cylinder, and high-pressure steam flows out at high speed from the high-pressure exhaust port of the steam chamber for the first time in the direction of the head end to drive the blades to do work.

[0008] A steam extraction port for using steam communicating with the left chamber is arranged at the lower part of the cylinder of the utility model.

[0009] A primary exhaust mixing chamber of the cylinder located at the head end is arranged at the place where the left chamber communicates with the primary exhaust port of the cylinder. The gas exhausted after the first expansion work is fully mixed, and after being exhausted through the primary exhaust port of the cylinder, it enters the steam-water separator for dehumidification to ensure that the dryness of the steam for the second work is ≥99%.

[0010] At the connection between the secondary steam inlet of the cylinder of the present utility model and the secondary steam chamber, there is a secondary steam inlet mixing chamber of the cylinder. The secondary steam inlet of the cylinder is located at the middle position of the lower part of the cylinder. The low-pressure steam enters the secondary steam mixing chamber of the cylinder through the secondary steam inlet of the cylinder to play a role of full mixing. After the secondary low-pressure steam is fully mixed, it is discharged from the secondary low-pressure exhaust port of the steam chamber and flows out at a high speed towards the tail of the machine to drive the blades to do work.

[0011] Both the primary steam chamber and the secondary steam chamber of the present utility model are provided with a plurality of interconnected and independent chambers to prevent the steam doing primary work from mixing with the steam doing secondary work.

[0012] The beneficial effects of the present utility model are as follows:

[0013] 1. Design of the intermediate dehumidification structure. The steam inlet regulating valve is placed at the middle position of the cylinder. When the high-pressure saturated steam is distributed, it expands and does work towards the head of the machine. When it reaches the head position, the humidity reaches 9%. Then it is discharged from the primary exhaust port of the cylinder at the head. The wet steam is dehumidified by the steam-water separator, and the dryness is ≥99%. Then it enters the secondary steam inlet of the cylinder in the middle of the cylinder and expands and does work towards the tail of the machine. The exhaust steam is discharged to the condenser to ensure that the dryness of the steam in the saturated steam turbine meets the requirements. For users using high-parameter saturated steam for pure power generation, this scheme has a reasonable design and a compact structure. Compared with the series connection of two units, it can significantly save costs and reduce the floor area. Moreover, it can ensure the steam dryness of the whole machine, while reducing the steam seal leakage and axial thrust.

[0014] 2. Design of the two-way exhaust flow structure. The steam inlet regulating valve is placed at the middle position of the cylinder. When the high-pressure saturated steam is distributed, it expands and does work towards the head of the machine. When it reaches the head position, it is then discharged from the primary exhaust port of the cylinder at the head and dehumidified by the steam-water separator, and then enters the secondary steam inlet of the cylinder in the middle of the cylinder and expands and does work towards the tail of the machine. The forces on the rotor impeller of the two-way exhaust structure are positive and negative, which can significantly reduce the axial thrust of the unit. At the same time, after the steam in the left chamber expands and does work through multiple pressure stages, the pressure at the front steam seal decreases significantly, effectively ensuring the sealing performance of the front steam seal and reducing the steam leakage.

[0015] 3. By setting a primary steam chamber, a secondary steam chamber and a high-pressure steam chamber seal in the middle of the cylinder, the cylinder is divided into two independent chambers on the left and right, which do not communicate with each other. After the steam expands and does work to the left, it is extracted and dehumidified and then expands and does work to the right to ensure the reasonable flow and work of the steam.

[0016] 4. For the problems that the high humidity of the steam after expansion work in a high-parameter saturated steam turbine is extremely likely to cause water erosion of components such as blades, existing solutions can meet the requirements. However, the existing solutions are not sufficient to meet the needs of different users; for pure power generation users, if the existing double-unit series connection scheme is blindly applied, there are defects such as cost, floor area, and functional redundancy. The through-flow structure of the present utility model is compact. For pure power generation users, using this single unit can meet the requirements, greatly saving costs and floor area.

[0017] 5. The structure of the present utility model is simple, reasonably designed, has field operability, and can ensure the steam dryness of the whole machine's through-flow part both in design and process operation, meeting the pure power generation needs of users on the premise of significantly reducing costs. At the same time, it can reduce the axial thrust and steam seal leakage, ensuring the safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the total schematic diagram of a double-unit high-parameter saturated steam turbine system in the prior art;

[0019] Figure 2 is the structural schematic diagram of the present utility model;

[0020] Figure 3 is Figure 2 the sectional view of the steam chamber in the A-A direction of

[0021] Figure 4 is the through-flow structural schematic diagram of the first- and second-stage steam working blades;

[0022] In the figure: 1. Cylinder, 2. Rotor shaft, 3. Front steam seal, 4. Rear steam seal, 5. Left blade, 6. Right blade, 7. Steam-water separator, 8. High-pressure steam chamber seal, 9. Diffusion nozzle, 10. High-pressure inter-stage seal, 11. Low-pressure inter-stage seal, 101. Left chamber, 102. Right chamber, 103. Primary steam chamber, 104. Secondary steam chamber, 105. Cylinder primary steam inlet, 106. Cylinder secondary steam inlet, 107. Cylinder primary exhaust port, 108. Low-pressure exhaust steam port, 109. Steam extraction port for use, 110. Cylinder primary exhaust mixing chamber, 111. Cylinder secondary steam inlet mixing chamber, 1031. Steam chamber primary high-pressure exhaust port, 1041. Steam chamber secondary low-pressure exhaust port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following gives the preferred embodiments of the utility model in conjunction with the drawings to elaborate the technical solutions of the present utility model in detail. Here, corresponding drawings will be given to explain the present utility model in detail. It should be particularly noted that the preferred embodiments described here are only used to illustrate and explain the present utility model, and are not used to limit or define the present utility model.

[0024] In the description of this embodiment, the terms "inside", "outside", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0025] like Figure 2 As shown, a bidirectional exhaust steam flow structure for intermediate dehumidification of high-parameter saturated steam is provided, which is provided with a cylinder 1, a rotor shaft 2 is axially assembled in the cylinder 1 in the front-to-back direction, the assembly of the rotor shaft 2 is realized by installing bearings in front and back, and a front steam seal 3 and a rear steam seal 4 for sealing are installed between the two ends of the rotor shaft 2 and the cylinder 1 to isolate the external air.

[0026] The cylinder 1 is divided into two independent chambers in the front-to-back direction, namely a left chamber 101 and a right chamber 102. The sizes of the left chamber 101 and the right chamber 102 are not limited and are adjusted according to design parameters. When compared with the flow structure effect of the prior art, the overall size of the entire flow structure is smaller. A plurality of left blades 5 mounted on the rotor shaft 2 are provided in the left chamber 101, and a plurality of right blades 6 mounted on the rotor shaft 2 are provided in the right chamber 102. The high-pressure stage, the low-pressure stage and the regulating stage in the chambers on both sides can be freely combined according to design parameters. The blades in the same chamber have the same rotation direction, and the blades in different chambers have opposite rotation directions. Pressure stage seals are performed between the blades. For example, the left blade 5 is a combination of a high-pressure stage and a regulating stage. In order to make the steam pass through the blades to do work instead of entering between the blades, the steam between each left blade is isolated by a high-pressure interstage seal 10. The right blade 6 is a low-pressure stage, and the low-pressure interstage seal 11 is used to isolate the steam between each pressure stage.

[0027] A primary steam chamber 103 and a secondary steam chamber 104 are provided between the left chamber 101 and the right chamber 102. The two independent steam chambers can prevent the steam for primary work and the steam for secondary work from mixing. The primary steam chamber 103 is communicated with the left chamber 101 through a primary high-pressure steam exhaust port 1031 of the steam chamber. The primary steam chamber 103 is located at the middle position of the upper part of the cylinder 1. High-pressure steam is discharged from the primary high-pressure steam exhaust port 1031 of the steam chamber and flows out at high speed towards the engine head direction to drive the blades to do work. The secondary steam chamber 104 is communicated with the right chamber 102 through a secondary low-pressure steam exhaust port 1041 of the steam chamber. The primary steam chamber 103 arranged above makes the primary high-pressure steam exhaust port 1031 of the primary steam chamber located at the upper part of the cylinder, expands towards the left engine head to drive the blades to do work, and the secondary steam chamber 104 arranged below makes the secondary low-pressure steam exhaust port 1041 of the steam chamber located at the lower part of the cylinder, expands towards the right engine tail to drive the blades to do work. The front rotating steam flow thrust and the rear rotating steam flow thrust both push the blades downward to drive the rotor to rotate and generate electricity. A cylinder primary steam inlet 105 for admitting steam communicated with the primary steam chamber 103 and a cylinder secondary steam inlet 106 for admitting steam communicated with the secondary steam chamber 104 are provided in the middle of the cylinder 1. A cylinder primary steam exhaust port 107 for exhausting steam communicated with the front end of the left chamber 101 and a low-pressure exhaust steam port 108 for exhausting steam communicated with the rear end of the right chamber 102 are also provided on the cylinder 1. A steam-water separator 7 is connected between the cylinder primary steam exhaust port 107 and the cylinder secondary steam inlet 106. With this structural design, the pressure borne by the front steam seal 3 is much smaller than that in the prior art, and the steam leakage risk can be significantly reduced. The pressure at the rear steam seal 4 is also relatively low, and no steam leakage will occur. While meeting the requirement of the dryness of the steam inside the saturated steam turbine, it has a small floor area, saves costs, and has a simple structure.

[0028] The specific implementation steps of an intermediate dehumidification two-way exhaust flow structure for high-parameter saturated steam are as follows: As Figure 2 shown, the specific steam flow expansion and work steps are as follows:

[0029] 1) High-pressure steam is introduced from the cylinder primary steam inlet 105 into the primary steam chamber 103, and then discharged from the primary high-pressure steam exhaust port 1031 of the steam chamber and introduced into the left chamber 101, flowing out at high speed towards the engine head direction to drive the left blades 5 to do work.

[0030] 2) The gas discharged after sufficient mixing and primary expansion work at the engine head is discharged through the cylinder primary steam exhaust port 107 and then enters the steam-water separator 7 for dehumidification to ensure that the dryness of the steam for secondary work ≥ 99%.

[0031] 3) The secondary steam inlet 106 of the cylinder is located at the middle position of the lower part of the cylinder. Low-pressure steam enters the secondary steam chamber 104 through the secondary steam inlet 106 of the cylinder. After the secondary low-pressure steam is fully mixed, it is discharged from the secondary low-pressure steam exhaust port 1041 of the steam chamber and flows out at high speed towards the tail of the machine to drive the right blade 6 to do work. The exhausted steam after doing work is discharged from the low-pressure exhausted steam exhaust port 108.

[0032] As Figure 4 shown, an axial thrust F is generated every time the rotor passes through a pressure stage. For example, four blades are used on the left side for four pressure stages, and seven blades are used on the right side for seven pressure stages. Therefore, the primary working steam towards the head of the machine is composed of the accumulation of 4 axial thrusts F1 to F4 to form the axial thrust F in front of the rotor. 前 , and the secondary working steam towards the tail of the machine is composed of the accumulation of 7 axial thrusts F5 to F 11 to form the axial thrust F behind the rotor. 后 . The total axial thrust F 总 received by the rotor = F 后 -F 前 . Since F 总 is the difference between the two thrusts, compared with the unit that expands backward in the same direction, the axial thrust is greatly reduced. Compared with the pressure of setting 11 blades, that is, 11 pressure stages, in the prior art, the bearing forces at both ends are reduced, but it does not affect the flow-through effect.

[0033] As Figure 2 , Figure 3 shown, both the primary steam chamber 103 and the secondary steam chamber 104 are provided with multiple interconnected and independent chambers to prevent the mixing of the primary working steam and the secondary working steam. A high-pressure steam chamber seal 8 is installed between the primary steam chamber 103, the secondary steam chamber 104 and the rotor shaft 2. The primary steam chamber 103 and the secondary steam chamber 104 can be formed separately without interference, or the primary and secondary working steams can be separated by the high-pressure steam chamber seal 301. As Figure 3 shown, four primary steam chambers 103 in the upper half can be independently arranged and marked as Ⅰ, Ⅱ, Ⅲ, Ⅳ respectively, and the secondary steam chamber 104 in the lower half can be divided into six independent ones, marked as Ⅴ, Ⅵ, Ⅶ, Ⅷ, Ⅸ, Ⅹ respectively, and the steam can be discharged into the chambers evenly by shunting.

[0034] As Figure 2 shown, a steam extraction port 109 for blocking when not in use is connected to the left chamber 101. The steam extraction port is opened at the lower part of the cylinder between the first left blade 5 and the second right blade 6 closest to the middle, which not only ensures appropriate steam temperature and pressure but also facilitates the connection of pipelines for steam extraction.

[0035] A cylinder primary exhaust mixing chamber 110 is provided at the connection between the left chamber 101 and the cylinder primary exhaust port 107, which can fully mix the gas discharged after the first-stage expansion work. After being discharged through the cylinder primary exhaust port 107, it enters the steam-water separator 7 for dehumidification to ensure that the dryness of the secondary work steam is ≥ 99%.

[0036] A cylinder secondary steam inlet mixing chamber 111 is provided at the connection between the cylinder secondary steam inlet 106 and the secondary steam chamber 104. The cylinder secondary steam inlet 106 is located at the middle position of the lower part of the cylinder 1. The low-pressure steam enters the cylinder secondary steam mixing chamber 111 through the cylinder secondary steam inlet 106 to play a role in full mixing. After the secondary low-pressure steam is fully mixed, it is discharged from the secondary low-pressure exhaust port 1041 of the steam chamber and flows out at high speed towards the tail of the machine to drive the blades to do work.

[0037] A diffusion nozzle 9 is installed at the connection between the cylinder primary steam inlet 105 and the primary steam chamber 103, which can not only play a role in evenly diffusing the steam but also be used for connecting with the high-pressure steam pipeline.

[0038] The above are only the preferred examples of the present utility model and are not used to limit or restrict the present utility model. For those skilled in the art of research or technology, various changes and modifications can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the scope of protection claimed by the present utility model.

Claims

1. An intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam, which is provided with a cylinder (1), a rotor shaft (2) is axially assembled in the cylinder (1) in the front-rear direction, and front steam seals (3) and rear steam seals (4) for sealing are installed between the two ends of the rotor shaft (2) and the cylinder (1), and is characterized in that: The cylinder (1) is divided into two independent chambers in the front-back direction, namely the left chamber (101) and the right chamber (102). Inside the left chamber (101), there are multiple left blades (5) assembled on the rotor shaft (2), and inside the right chamber (102), there are multiple right blades (6) assembled on the rotor shaft (2). The blades in the same chamber have the same helix direction, while the blades in different chambers have opposite helix directions. Pressure stage sealing is carried out between the blades. Between the left chamber (101) and the right chamber (102), there are a primary steam chamber (103) and a secondary steam chamber (104). The primary steam chamber (103) is communicated with the left chamber (101) through the primary high-pressure steam exhaust port (1031) of the steam chamber, and the secondary steam chamber (104) is communicated with the right chamber (102) through the secondary low-pressure steam exhaust port (1041) of the steam chamber. At the middle part of the cylinder (1), there are a primary steam inlet (105) of the cylinder that is communicated with the primary steam chamber (103) for steam inlet and a secondary steam inlet (106) of the cylinder that is communicated with the secondary steam chamber (104) for steam inlet. On the cylinder (1), there are also a primary exhaust port (107) of the cylinder that is communicated with the front end of the left chamber (101) for exhaust and a low-pressure exhaust port (108) of the exhausted steam that is communicated with the rear end of the right chamber (102) for exhaust. A steam-water separator (7) is connected between the primary exhaust port (107) of the cylinder and the secondary steam inlet (106) of the cylinder.

2. The intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam according to claim 1, characterized in that: The said primary steam chamber (103) is located at the middle position in the upper part of the cylinder (1). High-pressure steam is discharged from the primary high-pressure steam exhaust port (1031) of the steam chamber and flows out at high speed towards the engine head direction to drive the blades to do work.

3. The intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam according to claim 1, wherein: At the lower part of the said cylinder (1), there is a steam extraction port (109) that is communicated with the left chamber (101).

4. The intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam according to claim 1, characterized in that: At the communicating part between the said left chamber (101) and the primary exhaust port (107) of the cylinder, there is a primary exhaust mixing chamber (110) of the cylinder located at the engine head. The gas discharged after the first-stage expansion work is fully mixed and then discharged through the primary exhaust port (107) of the cylinder and enters the steam-water separator (7) to dehumidify and ensure that the dryness of the secondary work steam is ≥99%.

5. The intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam as described in claim 1, wherein: At the communicating part between the secondary steam inlet (106) of the cylinder and the secondary steam chamber (104), there is a secondary steam inlet mixing chamber (111) of the cylinder. The secondary steam inlet (106) of the cylinder is located at the middle position in the lower part of the cylinder (1). Low-pressure steam enters the secondary steam mixing chamber (111) of the cylinder through the secondary steam inlet (106) of the cylinder to play a role in full mixing. After the secondary low-pressure steam is fully mixed, it is discharged from the secondary low-pressure steam exhaust port (1041) of the steam chamber and flows out at high speed towards the engine tail direction to drive the blades to do work.

6. The intermediate dehumidifying and two-way exhaust flow structure for high-parameter saturated steam as claimed in claim 1, wherein: Both the said primary steam chamber (103) and the secondary steam chamber (104) are provided with multiple interconnected and independent chambers to prevent the steam for the first-stage work and the steam for the second-stage work from mixing.

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