A 330MW subcritical impulse-reaction combined steam turbine

Abstract

A 330MW subcritical impulse-reaction combined steam turbine belongs to the field of steam turbine structure optimization and transformation. The invention solves the problem that the current 330MW-level large-capacity unit with centralized heating demand cannot meet the basic electrical load and different heat load requirements of users and has low thermal efficiency. The steam turbine of the present application includes a No. 1 bearing box, a No. 2 bearing box, a No. 3 bearing box, a high- and medium-pressure cylinder, a low-pressure cylinder, a connecting pipe, a high- and medium-pressure rotor and a low-pressure rotor. The present application effectively improves the unit capacity, applies multi-stage small enthalpy drop and a new small gap steam seal technology, changes the high- and medium-pressure part from I+7+7 to I+14+10, reduces the pressure stage loss, improves the cylinder efficiency of the high- and medium-pressure modules as a whole, and improves the thermal economy of the power plant. The first eight stages of the medium-pressure module in the unit are reactionary pre-twisted assembly blades, and the last two stages are rotating partitions and impulse stages. The impulse-reaction combined arrangement is adopted, which can not only ensure the medium-pressure cylinder efficiency of the steam turbine, but also make the medium-pressure module have strong steam extraction adjustability, which can meet the use requirements of heat users.

Description

Technical Field

[0001] The invention belongs to the field of steam turbine structure optimization and transformation, and specifically relates to a 330MW subcritical impulse-reaction combined steam turbine. Background Art

[0002] At present, many thermal power plants are still responsible for heating and industrial steam centralized heating tasks in many regions. In order to adapt to the current development trend of the power industry and cater to the market transformation needs of industrial steam extraction turbines, the thermal efficiency of the unit is guaranteed to the maximum extent on the basis of meeting the user's electrical load and thermal load requirements. With the continuous deepening of the current power industry reform, the upgrading and transformation of large-capacity units of 330MW level with centralized heating needs will still occupy the mainstream of the market in the future. The current large-capacity units of 330MW level with centralized heating needs cannot meet the basic electrical load and different thermal load requirements of users. Therefore, it is in line with actual needs to develop a new type of 330MW unit with combined impact and reverse combined. Summary of the invention

[0003] The present invention solves the problem of upgrading and transforming the current 330MW-class large-capacity units with centralized heating demand, and further develops a 330MW subcritical impulse-reaction combined steam turbine;

[0004] A 330MW subcritical impulse-reaction combined steam turbine, the steam turbine comprising a No. 1 bearing box, a No. 2 bearing box, a No. 3 bearing box, a high-pressure cylinder, a low-pressure cylinder, a connecting pipe, a high-pressure rotor and a low-pressure rotor, the No. 1 bearing box, the No. 2 bearing box and the No. 3 bearing box are arranged in sequence from right to left, the high-pressure cylinder is arranged between the No. 1 bearing box and the No. 2 bearing box, the low-pressure cylinder is arranged between the No. 2 bearing box and the No. 3 bearing box, the connecting pipe is arranged on the top of the high-pressure cylinder and the low-pressure cylinder, and one end of the connecting pipe is connected to the exhaust end of the high-pressure cylinder, and the other end of the connecting pipe is connected to the intake end of the low-pressure cylinder, the high-pressure rotor is inserted in the high-pressure cylinder, and both ends of the high-pressure rotor extend to the outside of the high-pressure cylinder, one end of the high-pressure rotor is inserted in the No. 1 bearing box, the high-pressure cylinder is arranged between the No. 2 bearing box and the No. 3 bearing box, The other end of the medium-pressure rotor is inserted in the No. 2 bearing box, the low-pressure rotor is inserted in the low-pressure cylinder, and both ends of the low-pressure rotor extend to the outside of the low-pressure cylinder, one end of the low-pressure rotor is inserted in the No. 2 bearing box, and the other end of the low-pressure rotor is inserted in the No. 3 bearing box, one end of the low-pressure rotor inserted in the No. 2 bearing box and one end of the high- and medium-pressure rotor inserted in the No. 2 bearing box are fastened and connected by hydraulic bolts, and a high-pressure partition sleeve and a medium-pressure partition sleeve are provided in the high- and medium-pressure cylinders, the high-pressure partition sleeve is arranged close to the No. 1 bearing box, and the high-pressure partition sleeve is fixedly connected to the inner cylinder body of the high- and medium-pressure cylinders, the medium-pressure partition sleeve is arranged close to the No. 2 bearing box, and the medium-pressure partition sleeve is fixedly connected to the inner cylinder body of the high- and medium-pressure cylinders, and a rotating partition is provided on the exhaust end of the high- and medium-pressure cylinders, and the rotating partition is connected to the high The inner cylinder body of the high-pressure cylinder is fixedly connected, a nozzle group regulating stage is arranged between the high-pressure partition sleeve and the medium-pressure partition sleeve, the nozzle group regulating stage is fixedly connected to the inner cylinder body of the high-pressure and medium-pressure cylinders, high-pressure reverse dynamic and static blades are inserted on the inner wall of the high-pressure partition sleeve, and medium-pressure forward dynamic and static blades are inserted on the inner wall of the medium-pressure partition sleeve. A low-pressure partition sleeve is arranged in the low-pressure cylinder, and the low-pressure partition sleeve is fixedly connected to the inner cylinder body of the low-pressure cylinder. The low-pressure partition sleeve includes a low-pressure reverse partition sleeve and a low-pressure forward partition sleeve. The low-pressure reverse partition sleeve is arranged close to the No. 2 bearing box, and the low-pressure forward partition sleeve is arranged close to the No. 3 bearing box. A low-pressure reverse last-stage partition sleeve is arranged between the low-pressure reverse partition sleeve and the No. 2 bearing box, and the low-pressure reverse last-stage partition sleeve is fixedly connected to the inner cylinder body of the low-pressure cylinder. The low-pressure reverse partition sleeve A low-pressure reverse sub-final-stage partition sleeve is provided between the low-pressure reverse final-stage partition sleeve, and the low-pressure reverse sub-final-stage partition sleeve is fixedly connected to the inner cylinder body of the low-pressure cylinder; a low-pressure forward final-stage partition sleeve is provided between the low-pressure forward partition sleeve and the No. 3 bearing box, and the low-pressure forward final-stage partition sleeve is fixedly connected to the inner cylinder body of the low-pressure cylinder; a low-pressure forward sub-final-stage partition sleeve is provided between the low-pressure forward partition sleeve and the low-pressure forward final-stage partition sleeve, and the low-pressure forward sub-final-stage partition sleeve is fixedly connected to the inner cylinder body of the low-pressure cylinder; the inner walls of the low-pressure reverse partition sleeve, the low-pressure reverse final-stage partition sleeve and the low-pressure reverse sub-final-stage partition sleeve are all inserted with low-pressure reverse dynamic and static blades, and the inner walls of the low-pressure forward partition sleeve, the low-pressure forward final-stage partition sleeve and the low-pressure forward sub-final-stage partition sleeve are all inserted with low-pressure forward dynamic and static blades;

[0005] The beneficial effects of this application compared to the prior art are as follows:

[0006] 1. The 330MW subcritical impulse-reaction combined steam turbine proposed in the present invention effectively increases the unit capacity from 300MW to 330MW, improves the power of the whole machine, and under the premise of unchanged unit span, applies multi-stage small enthalpy drop and new small gap steam seal technology, and changes the high and medium pressure parts from I+7+7 to I+14+10, thereby reducing the pressure stage loss, improving the cylinder efficiency of the high and medium pressure modules as a whole, and improving the thermal economy of the power plant.

[0007] 2. The 330MW subcritical impulse-reaction combined steam turbine proposed in the present invention adopts a high- and medium-pressure combined cylinder design, and the cylinder body structure of the combined cylinder is a double-layer cylinder structure, which reduces the temperature gradient, fully utilizes the material properties, and reduces the material cost. The high and medium pressure inner cylinder adopts a new type of cast large inner cylinder, a high and narrow flange and a large rib structure, which can not only ensure the cylinder strength and steam tightness requirements, avoid cylinder cross-cavity leakage, but also improve the cylinder rigidity and prevent the operation waist from collapsing and affecting the operation radial clearance.

[0008] 3. The present invention proposes a 330MW subcritical impulse-reaction combined steam turbine. The first eight stages of the medium-pressure module in the unit are reaction-type pre-twisted assembled blades, and the last two stages are rotating partitions and impulse stages (medium-pressure terminal partitions). The impulse-reaction combined arrangement can not only ensure the medium-pressure cylinder efficiency of the steam turbine, but also make the medium-pressure module have strong steam extraction adjustability, which can meet the use requirements of heat users.

[0009] 4. The present invention proposes a 330MW subcritical impulse-reaction combined steam turbine. The medium and low pressure connecting pipes in the unit adopt bellows expansion joint connecting pipes. The expansion difference between the connecting pipe and the cylinder is completely absorbed by the flexibility of the bellows expansion joint. The connecting pipe has a reserved cylinder cutting interface. The connecting pipe butterfly valve participates in the steam extraction regulation. The last two stages of the low pressure are equipped with temperature measuring points and blade vibration online monitoring systems to monitor the operation and vibration of the last blades in real time, which can meet the user's low pressure cylinder zero output cylinder cutting transformation and steam extraction regulation requirements.

[0010] 5. The present invention proposes a 330MW subcritical impulse-reaction combined steam turbine. The medium and low pressure modules of the unit are arranged in a 2×6-stage symmetrical manner. The first stage has horizontally placed stationary blades, and the steam flow velocity at the blade outlet is uniform, and the total pressure loss coefficient is small. The low-pressure inner cylinder adopts a high-strength integral single-layer cast iron inner cylinder with good rigidity and good sealing. The 360° steam inlet volute annular barrier-free steam inlet channel has low pressure loss and good flow characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a longitudinal sectional schematic diagram of the steam turbine unit of the present invention;

[0012] Figure 2 It is a schematic diagram of the high and medium pressure module assembly of the steam turbine unit of the present invention;

[0013] Figure 3 It is a schematic diagram of the low-pressure module assembly of the steam turbine unit according to the present invention. DETAILED DESCRIPTION

[0014] Specific implementation method 1: Combination Figures 1 to 3The present embodiment is described. In the present embodiment, a 330MW subcritical impulse-reaction combined steam turbine is provided. The steam turbine comprises a No. 1 bearing box 1, a No. 2 bearing box 2, a No. 3 bearing box 3, a high-pressure cylinder 4, a low-pressure cylinder 5, a connecting pipe 6, a high-pressure rotor 11 and a low-pressure rotor 12. The No. 1 bearing box 1, the No. 2 bearing box 2 and the No. 3 bearing box 3 are arranged in sequence from right to left. The high-pressure cylinder 4 is arranged between the No. 1 bearing box 1 and the No. 2 bearing box 2, the low-pressure cylinder 5 is arranged between the No. 2 bearing box 2 and the No. 3 bearing box 3, the connecting pipe 6 is arranged at the top of the high-pressure cylinder 4 and the low-pressure cylinder 5, and one end of the connecting pipe 6 is connected to the exhaust end of the high-pressure cylinder 4, and the other end of the connecting pipe 6 is connected to the intake end of the low-pressure cylinder 5. The high-pressure rotor 11 is inserted into the high-pressure cylinder 4. The high and medium pressure rotors 11 are arranged in the middle and high pressure cylinders 4, and both ends of the high and medium pressure rotors 11 extend to the outside of the high and medium pressure cylinders 4, one end of the high and medium pressure rotors 11 is inserted in the No. 1 bearing box 1, and the other end of the high and medium pressure rotors 11 is inserted in the No. 2 bearing box 2, the low pressure rotor 12 is inserted in the low pressure cylinder 5, and both ends of the low pressure rotor 12 extend to the outside of the low pressure cylinder 5, one end of the low pressure rotor 12 is inserted in the No. 2 bearing box 2, and the other end of the low pressure rotor 12 is inserted in the No. 3 bearing box 3, one end of the low pressure rotor 12 inserted in the No. 2 bearing box 2 and one end of the high and medium pressure rotors 11 inserted in the No. 2 bearing box 2 are fastened and connected by hydraulic bolts, and a high pressure partition sleeve 7 and a medium pressure partition sleeve 8 are provided in the high and medium pressure cylinders 4, and the high pressure partition sleeve 7 is arranged close to the No. 1 bearing box 1, and the high pressure partition sleeve 7 is connected to the high and medium pressure cylinders 4. The inner cylinder body of the high-pressure cylinder 4 is fixedly connected, the medium-pressure partition sleeve 8 is arranged close to the No. 2 bearing box 2, and the medium-pressure partition sleeve 8 is fixedly connected to the inner cylinder body of the high-pressure cylinder 4, a rotating partition 10 is provided on the exhaust end of the high-pressure cylinder 4, and the rotating partition 10 is fixedly connected to the inner cylinder body of the high-pressure cylinder 4, a nozzle group adjustment stage 16 is provided between the high-pressure partition sleeve 7 and the medium-pressure partition sleeve 8, and the nozzle group adjustment stage 16 is fixedly connected to the inner cylinder body of the high-pressure cylinder 4, a high-pressure reverse dynamic and static blade 17 is inserted on the inner wall of the high-pressure partition sleeve 7, and a medium-pressure forward dynamic and static blade is inserted on the inner wall of the medium-pressure partition sleeve 8, a low-pressure partition sleeve 9 is provided in the low-pressure cylinder 5, and the low-pressure partition sleeve 9 is fixedly connected to the inner cylinder body of the low-pressure cylinder 5, and the low-pressure partition sleeve 9 includes a low-pressure reverse partition sleeve and a low-pressure forward partition sleeve , a low-pressure reverse baffle sleeve is arranged close to the No. 2 bearing box 2, a low-pressure forward baffle sleeve is arranged close to the No. 3 bearing box 3, a low-pressure reverse final-stage baffle sleeve 22 is arranged between the low-pressure reverse baffle sleeve and the No. 2 bearing box 2, and the low-pressure reverse final-stage baffle sleeve 22 is fixedly connected to the inner cylinder body of the low-pressure cylinder 5, a low-pressure reverse secondary-final-stage baffle sleeve 23 is arranged between the low-pressure reverse baffle sleeve and the low-pressure reverse final-stage baffle sleeve 22, and the low-pressure reverse secondary-final-stage baffle sleeve 23 is fixedly connected to the inner cylinder body of the low-pressure cylinder 5, a low-pressure forward final-stage baffle sleeve 25 is arranged between the low-pressure forward baffle sleeve and the No. 3 bearing box 3, and the low-pressure forward final-stage baffle sleeve 25 is fixedly connected to the inner cylinder body of the low-pressure cylinder 5, a low-pressure forward secondary-final-stage baffle sleeve 24 is arranged between the low-pressure forward baffle sleeve and the low-pressure forward final-stage baffle sleeve 25,The low-pressure forward second-last stage partition sleeve 24 is fixedly connected to the inner cylinder body of the low-pressure cylinder 5, and the inner walls of the low-pressure reverse partition sleeve, the low-pressure reverse final stage partition sleeve 22 and the low-pressure reverse second-last stage partition sleeve 23 are all inserted with low-pressure reverse moving and stationary blades 26, and the inner walls of the low-pressure forward partition sleeve, the low-pressure forward final stage partition sleeve 25 and the low-pressure forward second-last stage partition sleeve 24 are all inserted with low-pressure forward moving and stationary blades 27.

[0015] When modifying the existing units, the present application keeps the turbine foundation, bearing seat and bearing span unchanged, the cylinder and valve layout unchanged, the position of each pipeline interface unchanged, and the connection method and position with the generator unchanged. On this basis, the full flow upgrade of the turbine is carried out. This implementation method mainly includes high and medium pressure cylinders, low pressure cylinders, high / medium / low pressure partition sleeves, rotating partitions, connecting pipes, end steam seals, etc. In this application, the high and medium pressure modules adopt nozzle regulation, high pressure I+14 stages, and the flow adopts a regulating stage + reaction type arrangement; the medium pressure module adopts volute steam inlet and valve parameter adjustment, medium pressure 10 stages, and the flow adopts a reaction type + impulse type arrangement. The low pressure module adopts a volute 360° steam inlet method, low pressure 2×6 stages, the first stage of the flow is a horizontal guide vane, and a double split flow arrangement is adopted.

[0016] Specific implementation method 2: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the first embodiment is that the calibers of the low-pressure reverse baffle sleeve, the low-pressure reverse sub-final baffle sleeve 23 and the low-pressure reverse final baffle sleeve 22 are increased successively, and the calibers of the low-pressure forward baffle sleeve, the low-pressure forward sub-final baffle sleeve 24 and the low-pressure forward final baffle sleeve 25 are increased successively, and the caliber of the low-pressure reverse baffle sleeve is the same as that of the low-pressure forward baffle sleeve, the caliber of the low-pressure reverse sub-final baffle sleeve 23 is the same as that of the low-pressure forward sub-final baffle sleeve 24, and the caliber of the low-pressure reverse final baffle sleeve 22 is the same as that of the low-pressure forward final baffle sleeve 25. Other components and connection methods are the same as those of the first embodiment.

[0017] Specific implementation method three: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the second embodiment is that a high-pressure bridge steam seal 18 is provided between the nozzle group adjustment stage 16 and the medium-pressure partition sleeve 8, and the high-pressure bridge steam seal 18 is embedded in the inner cylinder body of the high-pressure cylinder 4. Other components and connection methods are the same as those of the second embodiment.

[0018] Specific implementation method four: Combination Figures 1 to 3This embodiment is described. The difference between this embodiment and the specific embodiment 1 is that a high-pressure exhaust balance ring 13 is provided on one end of the high-pressure cylinder 4 close to the No. 1 bearing box 1, a high-pressure end inner steam seal 14 is provided between the high-pressure exhaust balance ring 13 and the No. 1 bearing box 1, a high-pressure end outer steam seal 15 is provided between the high-pressure end inner steam seal 14 and the No. 1 bearing box 1, and the high-pressure exhaust balance ring 13, the high-pressure end inner steam seal 14 and the high-pressure end outer steam seal 15 are all embedded in the inner cylinder body of the high-pressure cylinder 4. Other components and connection methods are the same as those of the specific embodiment 3.

[0019] Specific implementation method five: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the fourth embodiment is that an inner steam seal 19 is provided at one end of the high and medium pressure cylinder 4 close to the second bearing box 2, an outer steam seal 20 is provided between the inner steam seal 19 and the second bearing box 2, and both the inner steam seal 19 and the outer steam seal 20 are embedded in the inner cylinder body of the high and medium pressure cylinder 4. Other components and connection methods are the same as those of the fourth embodiment.

[0020] Specific implementation method six: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the specific embodiment 5 is that the end face of the low-pressure positive final stage baffle sleeve 25 away from the low-pressure positive secondary final stage baffle sleeve 24 is provided with a No. 2 exhaust guide ring 29, a No. 1 low-pressure end steam seal 21 is provided between the No. 2 exhaust guide ring 29 and the No. 3 bearing box 3, and the end face of the low-pressure reverse final stage baffle sleeve 22 away from the low-pressure reverse secondary final stage baffle sleeve 23 is provided with a No. 1 exhaust guide ring 28, a No. 2 low-pressure end steam seal 30 is provided between the No. 1 exhaust guide ring 28 and the No. 2 bearing box 2, and the No. 2 exhaust guide ring 29, the No. 1 exhaust guide ring 28, the No. 1 low-pressure end steam seal 21 and the No. 2 low-pressure end steam seal 30 are all embedded in the inner cylinder body of the low-pressure cylinder 5. Other components and connection methods are the same as those of the specific embodiment 5.

[0021] Combined with the description of the second to sixth embodiments, the present application adopts a new type of small gap steam seal technology. The flow-through part adopts the combination of rotor embedded steam seal pieces and stator blade shroud sprayed with a grindable layer to improve the sealing performance, avoid inter-stage steam leakage and mutual friction between the rotor and the stator. In order to reduce steam leakage from the balance drum steam seal and improve the temperature field of the outer cylinder wall, the optimized steam seal structure adopts a two-way embedded steam seal. While ensuring the expansion difference margin, the number of steam seal teeth is appropriately increased. The fourth circle of steam seals after the balance drum is connected to the cylinder interlayer through the orifice opened on the inner cylinder. The high exhaust steam flowing into the inner and outer cylinder interlayer will appropriately cool the inner and outer cylinder wall temperatures to form a satisfactory temperature field.

[0022] Specific implementation method seven: Combination Figures 1 to 3This embodiment is described. The difference between this embodiment and the specific embodiment 6 is that a medium-pressure final-stage partition is provided between the rotating partition 10 and the second bearing box 2, the medium-pressure forward moving and stationary blades are 8-stage blades, and the medium-pressure forward moving and stationary blades, the rotating partition 10 and the medium-pressure final-stage partition together form a medium-pressure module. Other components and connection methods are the same as those of the specific embodiment 6.

[0023] In this embodiment, the first eight stages of the medium-pressure module in the unit are reaction-type pre-twisted assembled blades, and the last two stages are rotating partitions and impulse stages (medium-pressure terminal partitions). The combination of impulse and reaction is arranged to ensure the medium-pressure cylinder efficiency of the steam turbine and enable the medium-pressure module to have strong steam extraction adjustability, thereby meeting the use requirements of heat users.

[0024] Specific implementation method eight: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the sixth embodiment is that the high-pressure reverse moving and stationary blades 17 are 14-stage blades, and the high-pressure reverse moving and stationary blades 17 and the nozzle group adjustment stage 16 form a high-pressure module. Other components and connection methods are the same as those of the seventh embodiment.

[0025] In this embodiment, by changing the existing high and medium pressure modules from I+7+7 stage to I+14+10 stage, the pressure inter-stage loss is reduced, the cylinder efficiency of the high and medium pressure modules is improved as a whole, and the thermal economy of the power plant is improved.

[0026] Specific implementation method nine: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the sixth embodiment is that the high and medium pressure cylinders 4 and the low pressure cylinders 5 are both double-layer cylinder structures. The other components and connection methods are the same as those of the eighth embodiment.

[0027] In this embodiment, a high- and medium-pressure combined cylinder design is adopted, and the cylinder body structure of the combined cylinder is a double-layer cylinder structure, which reduces the temperature gradient, fully utilizes the material properties, and reduces the material cost. The high and medium pressure inner cylinder adopts a new type of cast large inner cylinder, a high and narrow flange and a large rib structure, which can not only ensure the cylinder strength and steam tightness requirements, avoid cylinder cross-cavity leakage, but also improve the cylinder rigidity and prevent the operation waist from collapsing and affecting the operation radial clearance.

[0028] Specific implementation method ten: Combination Figures 1 to 3 This embodiment is described. The difference between this embodiment and the sixth embodiment is that the connecting pipe 6 is a bellows expansion joint type connecting pipe. The other components and connection methods are the same as those of the ninth embodiment.

[0029] In this embodiment, the medium and low pressure connecting pipe 6 in the unit adopts a bellows expansion joint connecting pipe, and the expansion difference between the connecting pipe and the cylinder is completely absorbed by the flexibility of the bellows expansion joint. The connecting pipe reserves a cylinder cutting interface, and the connecting pipe butterfly valve participates in the steam extraction regulation. The low-pressure last two stages are equipped with temperature measurement points and blade vibration online monitoring systems to monitor the operation and vibration of the last blades in real time, which can meet the user's low-pressure cylinder zero-output cylinder cutting transformation and steam extraction regulation requirements.

[0030] The present invention has been disclosed as above with preferred implementation cases, but it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0031] Working principle:

[0032] When the steam turbine described in the present application is in use, new steam enters two high-pressure main steam regulating combined valves arranged on both sides of the high-pressure and medium-pressure cylinders and fixedly connected to the foundation from the bottom through the main steam pipe, and enters the four nozzle chambers of the high-pressure cylinder from the upper and lower halves of the high-pressure and medium-pressure outer cylinders in a certain order through four regulating valves (two on each side) through four high-pressure flexible steam guide pipes, and flows through the respective nozzle groups to the reverse impulse regulating stage and 14 reaction pressure stages, and then is discharged from the lower part of the high-pressure cylinder into the reheater. The reheated steam enters the two medium-pressure reheat main steam regulating combined valves placed on the floating supports on both sides of the turbine head from the front of the steam turbine through the reheat main steam pipe, and then is introduced from the bottom into the medium-pressure cylinder of the steam turbine through two medium-pressure steam guide pipes, and after passing through the 8 reaction pressure stages arranged in the medium pressure direction and two (9th and 10th) impulse pressure stages (the 9th stage is a rotary partition), it enters the low-pressure cylinder from the upper exhaust port of the medium-pressure cylinder through a connecting pipe. The low-pressure cylinder has a double-dividing structure. Steam flows in from the middle, passes through 6 levels of reaction pressure stages in both the forward and reverse directions, and is discharged downward from two exhaust ports into the condenser. Under industrial steam extraction conditions, the opening of the rotary baffle can be adjusted according to the requirements of industrial steam extraction parameters, so that the pressure in front of the rotary baffle gradually increases, and then the steam is extracted from the steam extraction port at the bottom of the medium-pressure cylinder, and another small part of the steam enters the rear of the rotary baffle stage, the middle row, the low-pressure cylinder, and the condenser; under heating steam extraction conditions, the opening of the butterfly valve on the connecting pipe can be gradually closed according to the requirements of heating parameters, so that the pressure in the middle row area gradually increases, and then the steam is extracted from the steam extraction port at the bottom of the medium-pressure cylinder, and another small part of the steam enters the low-pressure cylinder and the condenser.

Claims

1. A 330MW subcritical impulse-reaction combined steam turbine, the steam turbine comprising a No. 1 bearing box (1), a No. 2 bearing box (2), a No. 3 bearing box (3), a high- and medium-pressure cylinder (4), a low-pressure cylinder (5), a connecting pipe (6), a high- and medium-pressure rotor (11) and a low-pressure rotor (12), wherein the No. 1 bearing box (1), the No. 2 bearing box (2) and the No. 3 bearing box (3) are arranged in sequence from right to left, the high- and medium-pressure cylinder (4) is arranged between the No. 1 bearing box (1) and the No. 2 bearing box (2), the low-pressure cylinder (5) is arranged between the No. 2 bearing box (2) and the No. 3 bearing box (3), the connecting pipe (6) is arranged at the top of the high- and medium-pressure cylinder (4) and the low-pressure cylinder (5), and one end of the connecting pipe (6) is connected to the exhaust end of the high- and medium-pressure cylinder (4), and the other end of the connecting pipe (6) is connected to the intake end of the low-pressure cylinder (5). The high-pressure rotor (11) is inserted into the high-pressure cylinder (4), and both ends of the high-pressure rotor (11) extend to the outside of the high-pressure cylinder (4), one end of the high-pressure rotor (11) is inserted into the first bearing box (1), and the other end of the high-pressure rotor (11) is inserted into the second bearing box (2), the low-pressure rotor (12) is inserted into the low-pressure cylinder (5), and both ends of the low-pressure rotor (12) extend to the outside of the low-pressure cylinder (5), one end of the low-pressure rotor (12) is inserted into the second bearing box (2), and the other end of the low-pressure rotor (12) is inserted into the third bearing box (3), one end of the low-pressure rotor (12) inserted into the second bearing box (2) and one end of the high-pressure rotor (11) inserted into the second bearing box (2) are fastened and connected by hydraulic bolts, characterized in that: The high and medium pressure cylinders (4) are provided with a high pressure baffle sleeve (7) and a medium pressure baffle sleeve (8), the high pressure baffle sleeve (7) is arranged near the first bearing box (1), and the high pressure baffle sleeve (7) is fixedly connected to the inner cylinder body of the high and medium pressure cylinders (4), the medium pressure baffle sleeve (8) is arranged near the second bearing box (2), and the medium pressure baffle sleeve (8) is fixedly connected to the inner cylinder body of the high and medium pressure cylinders (4), a rotating baffle (10) is arranged on the exhaust end of the high and medium pressure cylinders (4), and the rotating baffle (10) is fixedly connected to the inner cylinder body of the high and medium pressure cylinders (4), and a rotating baffle (10) is arranged between the high pressure baffle sleeve (7) and the medium pressure baffle sleeve (8). The nozzle group regulating stage (16) is fixedly connected to the inner cylinder body of the high and medium pressure cylinders (4); the inner wall of the high pressure partition sleeve (7) is inserted with high pressure reverse dynamic and static blades (17); the inner wall of the medium pressure partition sleeve (8) is inserted with medium pressure forward dynamic and static blades; the low pressure cylinder (5) is provided with a low pressure partition sleeve (9); the low pressure partition sleeve (9) is fixedly connected to the inner cylinder body of the low pressure cylinder (5); the low pressure partition sleeve (9) includes a low pressure reverse partition sleeve and a low pressure forward partition sleeve; the low pressure reverse partition sleeve is arranged close to the second bearing box (2); the low pressure forward partition sleeve is arranged close to the third bearing The box (3) is provided with a low-pressure reverse final-stage partition sleeve (22) between the low-pressure reverse partition sleeve and the second bearing box (2), and the low-pressure reverse final-stage partition sleeve (22) is fixedly connected to the inner cylinder body of the low-pressure cylinder (5), a low-pressure reverse secondary final-stage partition sleeve (23) is provided between the low-pressure reverse partition sleeve and the low-pressure reverse final-stage partition sleeve (22), and the low-pressure reverse secondary final-stage partition sleeve (23) is fixedly connected to the inner cylinder body of the low-pressure cylinder (5), a low-pressure forward final-stage partition sleeve (25) is provided between the low-pressure forward partition sleeve and the third bearing box (3), and the low-pressure forward final-stage partition sleeve (25) is fixedly connected to the low-pressure cylinder (5), a low-pressure forward second-final-stage partition sleeve (24) is provided between the low-pressure forward partition sleeve and the low-pressure forward final-stage partition sleeve (25), and the low-pressure forward second-final-stage partition sleeve (24) is fixedly connected to the inner cylinder body of the low-pressure cylinder (5), the inner walls of the low-pressure reverse partition sleeve, the low-pressure reverse final-stage partition sleeve (22) and the low-pressure reverse second-final-stage partition sleeve (23) are all inserted with low-pressure reverse moving and stationary blades (26), and the inner walls of the low-pressure forward partition sleeve, the low-pressure forward final-stage partition sleeve (25) and the low-pressure forward second-final-stage partition sleeve (24) are all inserted with low-pressure forward moving and stationary blades (27); The calibers of the low-pressure reverse baffle sleeve, the low-pressure reverse second-final baffle sleeve (23) and the low-pressure reverse final baffle sleeve (22) are increased in sequence, and the calibers of the low-pressure forward baffle sleeve, the low-pressure forward second-final baffle sleeve (24) and the low-pressure forward final baffle sleeve (25) are increased in sequence, and the caliber of the low-pressure reverse baffle sleeve is the same as the caliber of the low-pressure forward baffle sleeve, the caliber of the low-pressure reverse second-final baffle sleeve (23) is the same as the caliber of the low-pressure forward second-final baffle sleeve (24), and the caliber of the low-pressure reverse final baffle sleeve (22) is the same as the caliber of the low-pressure forward final baffle sleeve (25); A No. 2 exhaust guide ring (29) is provided on the end surface of the low-pressure positive final stage baffle sleeve (25) away from the low-pressure positive secondary final stage baffle sleeve (24), a No. 1 low-pressure end steam seal (21) is provided between the No. 2 exhaust guide ring (29) and the No. 3 bearing box (3), a No. 1 exhaust guide ring (28) is provided on the end surface of the low-pressure reverse final stage baffle sleeve (22) away from the low-pressure reverse secondary final stage baffle sleeve (23), a No. 2 low-pressure end steam seal (30) is provided between the No. 1 exhaust guide ring (28) and the No. 2 bearing box (2), and the No. 2 exhaust guide ring (29), the No. 1 exhaust guide ring (28), the No. 1 low-pressure end steam seal (21) and the No. 2 low-pressure end steam seal (30) are all embedded in the inner cylinder body of the low-pressure cylinder (5); The high and medium pressure cylinders (4) and the low pressure cylinder (5) are both double-layer cylinder structures.

2. A 330MW subcritical impulse-reaction combined steam turbine according to claim 1, characterized in that: A high- and medium-pressure bridge steam seal (18) is provided between the nozzle group regulating stage (16) and the medium-pressure partition sleeve (8), and the high- and medium-pressure bridge steam seal (18) is embedded in the inner cylinder body of the high- and medium-pressure cylinder (4).

3. A 330MW subcritical impulse-reaction combined steam turbine according to claim 2, characterized in that: A high-pressure exhaust balance ring (13) is provided on one end of the high-pressure cylinder (4) close to the No. 1 bearing box (1); a high-pressure end inner steam seal (14) is provided between the high-pressure exhaust balance ring (13) and the No. 1 bearing box (1); a high-pressure end outer steam seal (15) is provided between the high-pressure end inner steam seal (14) and the No. 1 bearing box (1); and the high-pressure exhaust balance ring (13), the high-pressure end inner steam seal (14) and the high-pressure end outer steam seal (15) are all embedded in the inner cylinder body of the high-pressure cylinder (4).

4. A 330MW subcritical impulse-reaction combined steam turbine according to claim 3, characterized in that: An inner steam seal (19) is provided at one end of the high and medium pressure cylinder (4) close to the second bearing box (2), an outer steam seal (20) is provided between the inner steam seal (19) and the second bearing box (2), and both the inner steam seal (19) and the outer steam seal (20) are embedded in the inner cylinder body of the high and medium pressure cylinder (4).

5. A 330MW subcritical impulse-reaction combined steam turbine according to claim 4, characterized in that: A medium-pressure final-stage partition is provided between the rotating partition (10) and the second bearing box (2); the medium-pressure forward moving and stationary blades are 8-stage blades; the medium-pressure forward moving and stationary blades, the rotating partition (10) and the medium-pressure final-stage partition together form a medium-pressure module.

6. A 330MW subcritical impulse-reaction combined steam turbine according to claim 5, characterized in that: The connecting pipe (6) is a bellows expansion joint type connecting pipe.

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