A steam turbine dehumidification system and method

Abstract

The application discloses a steam turbine dehumidification system and a dehumidification method, in particular to a medium-temperature super-high-pressure garbage power generation steam turbine inter-stage dehumidification system and a dehumidification method. The dehumidification system comprises a partition sleeve, a dehumidification guide plate, a partition, a suction hole and a suction gap. The gap among the partition sleeve, the dehumidification guide plate and the partition forms a suction chamber together. One end of the suction chamber is communicated with the suction gap, and the other end is communicated with the suction hole. The suction gap and the suction hole utilize a suction pressure difference to complete suction of water drops near the top of a blade and send the water drops into the suction chamber. The suction gap is formed by the gap between the dehumidification guide plate and the partition. The suction hole is composed of through holes on the partition sleeve. The steam turbine dehumidification system and the dehumidification method can reduce exhaust steam humidity, improve steam turbine flow efficiency and improve the whole unit cycle efficiency.

Description

Technical Field

[0001] This invention pertains to steam turbine dehumidification systems and methods, specifically a steam turbine dehumidification system and method, and more particularly to an interstage dehumidification system and method for a medium-temperature ultra-high pressure waste-to-energy steam turbine. The steam turbine dehumidification system and method of this invention can reduce exhaust steam humidity, improve steam turbine flow efficiency, and enhance the overall unit circulation efficiency. Background Technology

[0002] Using waste incineration to drive steam turbine power generation is a major method for turning waste into valuable resources and has been widely adopted. With increasing attention to the overall benefits of waste-to-energy generation, methods to improve turbine cycle efficiency include increasing main steam parameters. However, waste incineration easily causes corrosion in the furnace, with higher temperatures leading to more severe corrosion. Therefore, the temperature of steam generated by waste incinerators is often limited, generally not exceeding 480℃. To improve unit cycle efficiency, the only solution is often to increase the main steam pressure, currently reaching a maximum of 13.2 MPa.

[0003] With increased main steam pressure but limited main steam temperature, the exhaust steam humidity in the turbine exhaust stages is significantly higher than in conventional units, exceeding 14% in extreme cases. This increased humidity reduces turbine flow efficiency, negatively impacting the overall unit cycle efficiency. Furthermore, the increased humidity causes severe water erosion in the exhaust stage components, leading to component damage, reduced unit lifespan, and safety hazards. Summary of the Invention

[0004] Currently, under conditions where the increase in main steam temperature is limited, the technical problem of severe water erosion on the flow passage components of the turbine exhaust stage caused by high-efficiency power generation, resulting in component damage, affecting unit lifespan, and posing safety hazards, remains unsolved. The purpose of this invention is to overcome the shortcomings of the prior art and provide a turbine dehumidification system and method. Using this invention, not only is exhaust steam humidity reduced, but the turbine flow efficiency is also improved, further enhancing the overall unit cycle efficiency. Simultaneously, the reduced humidity decreases the severe water erosion of the flow passage components in the turbine exhaust stage, thereby protecting the components, eliminating safety hazards, and extending unit lifespan.

[0005] The present invention is a steam turbine dehumidification system, characterized in that the dehumidification system includes: a baffle sleeve, a dehumidification guide plate, a baffle, a suction hole, and a suction slit;

[0006] The gap between the baffle sleeve, the dehumidifying guide plate, and the baffle together forms the suction chamber. One end of the suction chamber is connected to the suction slit, and the other end is connected to the suction hole. The suction slit and the suction hole use the suction pressure difference to complete the suction of water droplets near the top of the blade and send them into the suction chamber. The suction slit is formed by the gap between the dehumidifying guide plate and the baffle. The suction hole is formed by the through hole on the baffle sleeve.

[0007] Furthermore, the turbine dehumidification system is characterized in that: the partition plate includes a secondary partition plate and a final partition plate, and the through holes and suction holes provided on the partition plate sleeve are divided into radial suction holes and axial suction holes;

[0008] The gap between the partition sleeve, the dehumidifying guide plate, and the final stage partition forms suction chamber II; the gap between the partition sleeve, the dehumidifying guide plate, and the final stage partition forms suction chamber III; one end of suction chamber II is connected to suction slit 4-3, and the other end is connected to radial suction hole; one end of suction chamber III is connected to suction slit 3-6, and the other end is connected to radial suction hole.

[0009] Furthermore, the turbine dehumidification system is characterized in that it includes a turbine, and the dehumidification system further includes a front cylinder and an exhaust cylinder, with the gap between the partition sleeve, the front cylinder, and the exhaust cylinder forming a suction chamber I. The suction chamber I is connected to N suction holes, wherein the N suction holes include at least one axial suction hole and one radial suction hole; wherein the suction chamber I is connected to the suction chamber II through the radial suction hole, and the suction chamber I is connected to the suction chamber III through the radial suction hole; wherein the radial suction holes are disposed on the partition sleeve and are uniformly or non-uniformly distributed around the circumference; the axial suction holes are disposed on the bearing shoulder of the partition sleeve and are uniformly or non-uniformly distributed around the circumference.

[0010] Furthermore, the aforementioned radial suction holes and axial suction holes are evenly distributed along the circumference, with the diameter of the radial suction hole connecting suction chamber I and suction chamber II being D1, and the diameter of the radial suction hole connecting suction chamber I and suction chamber III being D2.

[0011] Among them, D1 and D2 may be the same or different; the diameter D3 of the axial suction hole may be the same or different.

[0012] The front cylinder, the exhaust cylinder, and the gap between the partition sleeve and the front cylinder and the exhaust cylinder together form the suction chamber I. The suction chamber I is connected to N suction holes, of which at least one axial suction hole and one radial suction hole are present. The diameter of D3 is X times (twice) of D1 and D2.

[0013] Furthermore, the turbine dehumidification system is characterized in that:

[0014] The dehumidification guide plate is installed on the diaphragm sleeve, and the secondary and final stage diaphragms are placed on the diaphragm sleeve. The steam extraction guide plate is located between the two diaphragms and cooperates with the radial steam seal of the secondary and final stage diaphragms and the steam inlet side drainage groove of the final stage diaphragm to form suction chambers I and II. The two suction chambers are connected to the outer chamber of the diaphragm sleeve through radial suction holes, and then connected to the exhaust chamber after the final stage diaphragm through the axial suction holes of the diaphragm sleeve. This makes the suction gaps before and after the dehumidification guide plate have suction pressure difference, which can draw water droplets concentrated near the blade tip due to centrifugal force after the secondary and final stages into the suction chamber, and then discharge them through the two-stage suction holes, and finally enter the condenser together with the exhaust steam.

[0015] Furthermore, the aforementioned technical solution is further improved, wherein the turbine dehumidification system is characterized in that: the dehumidification system has two suction slits, which are as follows:

[0016] A dehumidifying guide plate is designed in the middle of the baffle sleeve. The dehumidifying guide plate cooperates with the radial steam seal of the secondary and final stage baffle to form the first suction slit; it cooperates with the condensate drain groove of the final stage baffle to form the second suction slit; at the same time, the guide plate cooperates with the two stages of baffles to form suction chambers II and III; by using the two additional suction slits, that is, the suction pressure difference is established inside and outside the suction slits. When wet steam flows out from the high-speed rotating secondary and final stage moving blades, the water droplets are concentrated near the blade tip due to centrifugal force, and can be captured by the designed first and second suction slits. The captured water droplets are collected and guided by the suction chambers and finally flow into the condenser, thereby achieving the purpose of removing some steam water droplets inside the flow path.

[0017] Furthermore, the turbine dehumidification system is characterized by the following: the pressure, size, and area of ​​the suction slit are specifically defined as follows:

[0018] The gap range of the suction slit is 0.5 to 2.0 mm, and the suction area of ​​the suction slit around its entire circumference is S1; the total suction area S2 of the suction hole φD1 corresponding to the suction slit is 2 to 3 times the total area S1 of the suction slit; the total suction area S3 of the axial suction hole φD2 of the partition sleeve around its entire circumference is the sum of the total areas of the two sets of radial suction holes φD1.

[0019] The pressure before the final stage diaphragm is Pa, and the exhaust back pressure is Pb. The pressure in suction chamber I is established to Pb through the axial suction hole φD2 of the diaphragm sleeve, and the pressure in suction chambers II and III is established to Pb through two sets of radial suction holes φD1. This creates a suction pressure difference ΔP inside and outside the suction gap, where ΔP = Pa - Pb. ΔP is the driving force for the suction gap to remove water droplets from the wet steam.

[0020] The pressure difference is ΔP, and ΔP = Pa - Pb.

[0021] Furthermore, the turbine dehumidification system is characterized in that: the turbine dehumidification system is applicable to an interstage dehumidification system for a medium-temperature ultra-high pressure waste-to-energy turbine.

[0022] Another aspect of the present invention is: a method for interstage dehumidification of a medium-temperature ultra-high pressure waste-to-energy turbine adapted to the above-mentioned method, characterized by comprising the following steps:

[0023] Step 1: Set up suction holes and suction slots, use the rotation of blades to generate pressure, and establish a pressure difference;

[0024] Step 2: Use the funnel-shaped structure to collect water droplets in the water vapor and use the pressure difference to suck away the water droplets.

[0025] Compared with the prior art, the present invention has the following features and beneficial effects:

[0026] (1) The present invention has a simple structure and does not require additional adjustment and control. It can be run randomly. It can effectively extract water droplets from the wet steam out of the main flow, reduce the humidity of the steam entering the final flow, avoid severe water erosion of the final stage moving blades, and prevent damage to the components. At the same time, it can reduce the loss of wet steam and improve the flow efficiency of the unit.

[0027] (2) By adopting the present invention, not only is the exhaust humidity reduced, but the turbine flow efficiency is also improved, and the overall unit cycle efficiency is further improved. At the same time, the reduction in humidity reduces the strong water erosion of the flow components of the exhaust section of the unit by steam, thereby protecting the components, eliminating safety hazards, improving the unit life, and making it highly practical. Attached Figure Description

[0028] Figure 1 This is a schematic cross-sectional view illustrating the overall structural principle of the present invention;

[0029] Figure 2 This is a schematic diagram of the suction chamber principle of the present invention;

[0030] Figure 3 This is a schematic diagram of the wet steam suction flow according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the suction seam principle. Figure 1 (Enlarged view of the h-view)

[0032] Figure 5 This is a cross-sectional view of the AA suction port;

[0033] Figure 6 This is a cross-sectional view of the BB suction port;

[0034] Figure 7 This is a cross-sectional view of the CC hydrophobic pores.

[0035] In the diagram: 1-front cylinder, 2-exhaust cylinder, 3-diaphragm sleeve, 4-secondary and final stage diaphragm, 5-secondary and final stage moving blade, 6-final stage diaphragm, 7-final stage moving blade. Detailed Implementation

[0036] The present invention will be further illustrated by the following examples.

[0037] Example: See attached diagram.

[0038] A steam turbine dehumidification system, the dehumidification system comprising:

[0039] Partition sleeve, dehumidification guide plate, partition, suction hole and suction slot;

[0040] The gap between the baffle sleeve, the dehumidifying guide plate, and the baffle together forms the suction chamber. One end of the suction chamber is connected to the suction slit, and the other end is connected to the suction hole. The suction slit and the suction hole use the suction pressure difference to draw water droplets near the top of the blades into the suction chamber. The suction slit is formed by the gap between the dehumidifying guide plate and the baffle. The suction hole is formed by the through hole on the baffle sleeve.

[0041] Furthermore, in this dehumidification system, the partition includes a secondary partition and a final partition, with through-holes on the partition sleeve divided into radial suction holes and axial suction holes. The gap between the partition sleeve, the dehumidification guide plate, and the secondary partition forms suction chamber II; the gap between the partition sleeve, the dehumidification guide plate, and the final partition forms suction chamber III. Suction chamber II is connected at one end to suction seam 4-3 and at the other end to the radial suction hole; suction chamber III is connected at one end to suction seam 3-6 and at the other end to the radial suction hole.

[0042] Further improvements to the aforementioned technical solution, embodiments of the present invention also disclose another dehumidification system, which further includes: a front cylinder and an exhaust cylinder, with the gap between the partition sleeve, the front cylinder, and the exhaust cylinder forming a suction chamber I. The suction chamber I is connected to N suction holes, wherein the N suction holes include at least one axial suction hole and one radial suction hole; wherein the suction chamber I is connected to the suction chamber II through the radial suction hole, and the suction chamber I is connected to the suction chamber III through the radial suction hole; wherein the radial suction holes are disposed on the partition sleeve and are uniformly or non-uniformly distributed around the circumference; the axial suction holes are disposed on the bearing shoulder of the partition sleeve and are uniformly or non-uniformly distributed around the circumference.

[0043] Furthermore, the aforementioned radial and axial suction holes are evenly distributed along the circumference. The diameter of the radial suction hole connecting suction chamber I and suction chamber II is D1, and the diameter of the radial suction hole connecting suction chamber I and suction chamber III is D2.

[0044] Among them, D1 and D2 may be the same or different; the diameter D3 of the axial suction hole may be the same or different.

[0045] The front cylinder, the exhaust cylinder, and the gap between the partition sleeve and the front cylinder and the exhaust cylinder together form a suction chamber I. The suction chamber I is connected to N suction holes, of which at least one axial suction hole and one radial suction hole are present. The diameter of D3 is twice or X times that of D1 and D2, respectively.

[0046] Further improvements to the aforementioned technical solution, embodiments of the present invention also disclose another dehumidification system.

[0047] The dehumidification guide plate is installed on the diaphragm sleeve, and the secondary and final stage diaphragms are placed on the diaphragm sleeve. The steam extraction guide plate is located between the two diaphragms and cooperates with the radial steam seal of the secondary and final stage diaphragms and the steam inlet side drainage groove of the final stage diaphragm to form suction chambers I and II. The two suction chambers are connected to the outer chamber of the diaphragm sleeve through radial suction holes, and then connected to the exhaust chamber after the final stage diaphragm through the axial suction holes of the diaphragm sleeve. This makes the suction gaps before and after the dehumidification guide plate have suction pressure difference, which can draw water droplets concentrated near the blade tip due to centrifugal force after the secondary and final stages into the suction chamber, and then discharge them through the two-stage suction holes, and finally enter the condenser together with the exhaust steam.

[0048] The front cylinder 1 and the exhaust cylinder 2 are connected by a vertical flange. The partition sleeve 3 is installed on the exhaust cylinder 2 by a shoulder. At the same time, a sealing rib is designed on the partition sleeve 3 to cooperate with the front cylinder 1, so that the front cylinder 1, the exhaust cylinder 2 and the partition sleeve 3 form a chamber I.

[0049] The second-to-last stage baffle 4 and the second-to-last stage moving blade 5 cooperate to form the complete second-to-last stage flow passage, and the last stage baffle 6 and the last stage moving blade 7 cooperate to form the complete last stage flow passage. Both the second-to-last stage baffle 3 and the last stage baffle 6 are installed on the baffle sleeve 3. The radial steam seal of the second-to-last stage baffle 4 cooperates with the dehumidification guide plate of the baffle sleeve 3 to form a 4-3 suction slot, and the dehumidification guide plate of the baffle sleeve 3 cooperates with the steam inlet side condensate drain groove of the last stage baffle 6 to form a 3-6 suction slot. Simultaneously, the second-to-last stage baffle 4 and the baffle sleeve 3 form chamber II, and the baffle sleeve 3 and the last stage baffle 6 form chamber III.

[0050] First, a sealing rib was added, forming suction chamber I through the sealing rib, load-bearing shoulder, and front cylinder to establish the pressure differential of the suction slot. Second, a dehumidifying guide plate was designed in the middle of the diaphragm sleeve. This dehumidifying guide plate cooperates with the radial steam seal of the second-to-last stage diaphragm to form a suction slot; it also cooperates with the drainage groove of the last stage diaphragm to form a second suction slot; simultaneously, the guide plate, in cooperation with the two stages of diaphragms, also forms suction chambers II and III. Additionally, suction holes are opened radially around the entire circumference of the diaphragm sleeve, such as... Figure 5 A cross-sectional view of the AA suction hole, connecting suction chamber I, chamber II, and chamber III; an axial suction hole is made on the load-bearing shoulder of the partition sleeve, as shown. Figure 6 BB suction port cross-sectional view, connecting suction chamber I and flow exhaust.

[0051] The gap range of the suction slit is 0.5~2.0mm, and the total suction area of ​​the suction slit is S1. The total suction area S2 of the suction hole φD1 corresponding to the suction slit is 2~3 times the total area S1 of the suction slit. The total suction area S3 of the axial suction hole φD2 of the baffle sleeve is the sum of the total areas of the two sets of radial suction holes φD1. The pressure before the last stage baffle is Pa, and the exhaust back pressure is Pb. Through the axial suction hole φD2 of the baffle sleeve, the pressure in suction chamber I is established to Pb, and then through the two sets of radial suction holes φD1, the pressure in suction chambers II and III is established to Pb. This creates a suction pressure difference ΔP inside and outside the suction slit, ΔP=Pa-Pb, and ΔP is the driving force for the suction slit to extract and dehumidify water droplets in the wet steam.

[0052] When wet steam flows out from the second-to-last stage moving blades, due to the circumferential velocity component of the steam itself, water droplets in the wet steam are thrown to the outer edge of the flow path by centrifugal force and accumulate behind the top of the moving blades. The first inverted funnel-shaped water collection area designed here can reduce the axial velocity of the water droplets, causing them to settle. Then, the water droplets are drawn into the suction chamber II through the pressure difference ΔP between the inside and outside of the suction slit 4-3, where they are further deposited. At the same time, along the steam flow direction, behind the first inverted funnel-shaped water collection area, a similar inverted funnel-shaped water collection area is designed to collect water droplets escaping from the first suction slit. Then, the water droplets are drawn into the suction chamber III through the pressure difference ΔP between the inside and outside of the suction slit 3-6 for deposition, improving the water droplet collection efficiency.

[0053] Water deposited in suction chambers II and III passes through... Figure 5 Water flows into suction chamber I through suction orifice n-φD1. Water from suction chambers II and III mixes and concentrates in suction chamber I, and then... Figure 6 The water flows out of suction chamber I through the n-φD2 suction hole and mixes with the unit's exhaust steam. Most of the water droplets discharged from n-φD2 will deposit in the water collection tank in the lower half of the exhaust cylinder behind the baffle sleeve, and then... Figure 7 The water drain from the 3-φD3 hole flows into the lower half of the exhaust cylinder and directly into the condenser. A small amount of water droplets will flow with the main flow into the exhaust volute, and then, after passing through several flow channel turns, will eventually also enter the condenser.

[0054] The above specific technical solutions are only used to illustrate the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above specific technical solutions, those skilled in the art should understand that modifications can still be made to the above specific technical solutions, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

[0055] The technical contents of this invention and those not specifically described in the above embodiments are the same as those in the prior art.

Claims

1. A steam turbine dehumidification system, characterized in that: The dehumidification system includes: a partition sleeve, a dehumidification guide plate, a partition, a suction hole, and a suction slit; The gap between the baffle sleeve, the dehumidifying guide plate, and the baffle together forms the suction chamber. One end of the suction chamber is connected to the suction slit, and the other end is connected to the suction hole. The suction slit and the suction hole use the suction pressure difference to complete the suction of water droplets near the tip of the blade and send them into the suction chamber. The suction slit is formed by the gap between the dehumidifying guide plate and the baffle. The suction hole is formed by the through hole on the baffle sleeve. Specifically, the dehumidification guide plate is installed on the partition sleeve, and the secondary and final stage partitions are placed on the partition sleeve. The steam extraction guide plate is located between the two stage partitions and cooperates with the radial steam seal of the secondary and final stage partitions and the steam inlet side drain groove of the final stage partition to form suction chamber II and suction chamber III, respectively. The two suction chambers are connected to the outer chamber of the partition sleeve through radial suction holes, and then connected to the exhaust chamber after the final stage partition through the axial suction holes of the partition sleeve.

2. The turbine dehumidification system according to claim 1, characterized in that: The partition includes a secondary partition and a final partition, and the through-hole suction holes provided on the partition sleeve are divided into radial suction holes and axial suction holes. The gap between the partition sleeve, the dehumidifying guide plate, and the final stage partition forms the suction chamber II; the gap between the partition sleeve, the dehumidifying guide plate, and the final stage partition forms the suction chamber III; one end of the suction chamber II is connected to the suction slit I, and the other end is connected to the radial suction hole D1; one end of the suction chamber III is connected to the suction slit II, and the other end is connected to the radial suction hole D2.

3. The turbine dehumidification system according to claim 2, characterized in that: The dehumidification system includes a steam turbine and further comprises a front cylinder and an exhaust cylinder. The gap between the diaphragm sleeve, the front cylinder, and the exhaust cylinder together forms a suction chamber I. The suction chamber I is connected to N suction holes, wherein the N suction holes include at least one axial suction hole, at least one radial suction hole D1, and at least one radial suction hole D2. The suction chamber I is connected to a suction chamber II through the radial suction hole D1, and the suction chamber I is connected to a suction chamber III through the radial suction hole D2. The radial suction holes are disposed on the diaphragm sleeve and are uniformly or non-uniformly distributed around the circumference. The axial suction holes are disposed on the bearing shoulder of the diaphragm sleeve and are uniformly or non-uniformly distributed around the circumference.

4. The turbine dehumidification system according to claim 3, characterized in that: The aforementioned radial suction holes and axial suction holes are evenly distributed along the circumference.

5. The turbine dehumidification system according to claim 2, characterized in that: The gap range of the suction slit is 0.5–2.0 mm; The pressure before the last stage diaphragm is Pa, and the exhaust back pressure is Pb. The pressure in suction chamber I is established as Pb through the axial suction hole D3 of the partition sleeve, and the pressure in suction chambers II and III is established as Pb through two sets of radial suction holes. Thus, a suction pressure difference ΔP is formed inside and outside the suction slit, ΔP=Pa-Pb, and ΔP is the driving force for the suction slit to dehumidify water droplets in wet steam.

6. The turbine dehumidification system according to any one of claims 1 to 5, characterized in that: This turbine dehumidification system is suitable for an interstage dehumidification system of a medium-temperature ultra-high pressure waste-to-energy turbine.

7. A dehumidification method for a steam turbine dehumidification system according to any one of claims 1 to 6, characterized in that: The steps include the following: Step 1: Set up suction holes and suction slots, use the rotation of blades to generate pressure, and establish a pressure difference; Step 2: Use the funnel-shaped structure to collect water droplets in the water vapor and use the pressure difference to suck away the water droplets.

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