Bypass regenerative turbine system for low-load feed water heating of thermal power generating unit

Abstract

The invention relates to the technical field of deep peak regulation and energy conservation and consumption reduction, and discloses a bypass regenerative turbine system for low-load feed water heating of a thermal power generating unit, which comprises the following modules: a boiler, a main throttle valve, a low-load bypass regulating valve, a main regulating valve, a bypass regenerative turbine and a feed water temperature regulator. A main steam outlet pipeline of the boiler is connected with a main steam valve, and an outlet flange of the main steam valve is connected to an inlet of a main regulating valve. An existing steam turbine steam cycle power generation system is improved, a bypass regenerative turbine special for boiler feed water temperature adjustment is arranged, the turbine exhaust pressure and the exhaust steam flow are controlled by changing the opening degree of a bypass adjusting valve and the rotating speed of the turbine, and the boiler feed water temperature is always within the optimal temperature range; and moreover, part of non-throttling main steam during low-load constant-pressure operation can be utilized to improve the steam power capability, the coal consumption rate of the unit is reduced, and the overall energy-saving level of the unit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep peak regulation and energy saving and consumption reduction, in particular to a bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit. BACKGROUND

[0002] The stable operation of the SCR flue gas denitration system in the thermal power industry is the main means to achieve the goal of nitrogen oxide emission reduction, and has been widely used. In the thermal power unit, the backheating extraction steam pressure is basically proportional to the unit load, and as the unit load decreases, the boiler feedwater temperature will also decrease, causing the flue gas temperature at the outlet of the boiler economizer to decrease accordingly. When the flue gas temperature is too low, it will cause the catalyst activity to decrease, and at the same time, ammonia and sulfur trioxide will generate ammonium bisulfate under low-temperature flue gas, which will adhere to the denitration catalyst and the air preheater, and adsorb dust, causing the denitration catalyst and the air preheater to be blocked, and the pressure difference of the denitration reactor and the air preheater to slowly increase, thereby reducing the output of the induced draft fan and affecting the unit output. Therefore, it is crucial to control the flue gas temperature at the inlet of the denitration reactor.

[0003] As the proportion of new energy in the power grid gradually increases, the demand for peak regulation power also gradually increases. Compared with new energy power, coal power has good peak regulation performance, and thermal power units, especially coal power units, will continue to operate at low load or deep peak regulation in the next few years, so how to increase the feedwater temperature under low load conditions while considering energy saving and consumption reduction has become the pursuit goal of thermal power units. The steam quantity required by the steam turbine at low load decreases. Since the through-flow area of the steam turbine is not adjustable, the steam pressure is often reduced to reduce the steam density to ensure the matching of the steam volume flow and the through-flow area of the steam turbine. As can be seen, the steam inlet pressure of the steam turbine is approximately proportional to the unit load, and the lower the load, the lower the required steam inlet pressure. At this time, the boiler will continue to provide steam at a relatively high pressure, and there is a certain pressure difference between the boiler and the steam turbine that can be utilized. SUMMARY

[0004] The present application provides a bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit to solve the problems raised in the background art.

[0005] The present application provides the following technical solution: a bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit, comprising the following modules: a boiler, a main steam valve, a low-load bypass regulating valve, a main regulating valve, a bypass heat recovery turbine, and a feedwater temperature regulator. The main steam outlet pipeline of the boiler is connected to the main steam valve, the outlet flange of the main steam valve is connected to the inlet of the main regulating valve, part of the steam after the main steam valve enters the bypass heat recovery turbine through the low-load bypass regulating valve, and the feedwater temperature regulator detects the feedwater temperature entering the boiler in real time. Boiler: convert the chemical energy of fuel into heat energy, and then generate high-temperature and high-pressure steam or hot water, and supply steam to the main steam valve; Main steam valve: control the on-off and flow regulation of the main steam discharged by the boiler, and cut off the steam supply in emergency to ensure system safety, supply the main steam to the main regulating valve, and supply part of the steam to the low-load bypass regulating valve; Low-load bypass regulating valve: ensure the stable operation of the steam power system under low-load, start-up and shutdown conditions, and supply steam to the bypass heat recovery turbine; Main regulating valve: ensure the stable and efficient operation of the equipment by dynamically adjusting the fluid parameters, supply the main steam from the main steam valve, and supply steam to the conventional steam turbine unit; Bypass heat recovery turbine: optimize the heat recovery process, balance the system steam distribution and improve the energy utilization efficiency, use the bypass steam supplied by the low-load bypass regulating valve to do work, realize energy recovery, and the exhaust steam of the bypass heat recovery turbine enters the feedwater temperature regulator to heat the boiler water; Feedwater temperature regulator: accurately control the boiler feedwater temperature to be stable at the set value.

[0006] As a preferred technical solution of the present application, the low-load bypass regulating valve comprises a three-way pipe, a main channel is arranged in the center of the three-way pipe, two ports of the main channel are connected with the main steam valve and the main regulating valve through pipelines, a bypass channel is arranged at one end of the three-way pipe away from the main channel, an auxiliary pipe is fixedly sleeved on the side wall of the bypass channel, a piston is slidably sleeved on the inner wall of the auxiliary pipe, a baffle is rotatably sleeved on the inner wall of the bypass channel, a sealing ring is fixedly sleeved on the outer edge of the baffle, the outer edge of the sealing ring is tightly attached to the inner wall of the bypass channel, a spring is fixedly connected to the side surface of the piston, and the other end of the spring away from the piston is fixedly connected to the inner wall of the auxiliary pipe.

[0007] As a preferred technical solution of the present application, the bottom of the baffle is fixedly assembled with a rotating frame, the outer edge of the rotating frame is rotatably sleeved with the inner wall of the auxiliary pipe, the outer edge of the rotating frame is fixedly sleeved with a baffle blade, the bottom of the rotating frame is fixedly assembled with a positioning wheel, the outer edge of the positioning wheel is fixedly sleeved with a second tension spring, the other end of the second tension spring away from the positioning wheel is fixedly connected to the inner wall of the auxiliary pipe, a limiting groove is arranged on the outer edge of the rotating frame, a rotating groove is arranged on the inner wall of the auxiliary pipe, and the inner wall of the rotating groove is rotatably sleeved with the outer edge of the baffle blade.

[0008] As a preferred technical scheme of the present application, the auxiliary pipe is fixedly sleeved with a connecting pipe near the inner wall of both sides, the inner wall of the baffle is fixedly assembled with a magnet plate one, the outer edge of the magnet plate one is rotatably connected with the inner wall of the rotating groove, the inner wall of the auxiliary pipe is fixedly assembled with a magnet plate two, the adjacent side of the magnet plate one and the magnet plate two is adsorbed, the side of the magnet plate two is fixedly assembled with a Hall sensor, the Hall sensor is electrically connected with the magnet plate two, and the inner wall of the auxiliary pipe is fixedly assembled with an electromagnetic valve exhaust pipe, and the electromagnetic valve exhaust pipe is electrically connected with the Hall sensor.

[0009] As a preferred technical scheme of the present application, the outer edge of the tee pipe is fixedly sleeved with a fixed ring, the side of the fixed ring is fixedly assembled with an auxiliary ring, the inner wall of the auxiliary ring is fixedly assembled with a communication pipe, the outer edge of the communication pipe is fixedly sleeved with a sleeve ring, the inner wall of the sleeve ring is fixedly sleeved with a gas guide pipe, the outer edge of the gas guide pipe is fixedly sleeved with the inner wall of the fixed ring, the inner wall of the communication pipe is fixedly sleeved with a bottom ring, the bottom of the bottom ring is fixedly assembled with a pressing ring, the bottom of the pressing ring is fixedly assembled with a rubber pad, and the bottom of the rubber pad is fixedly sleeved with the outer edge of the tee pipe.

[0010] As a preferred technical scheme of the present application, the inner wall of the communication pipe is slidably sleeved with a circular plate, the inner wall of the circular plate is fixedly sleeved with a connecting rod, the bottom of the connecting rod is fixedly assembled with a magnet piece, the inner wall of the bottom ring is fixedly sleeved with a coil, the inner wall of the coil is slidably sleeved with the outer edge of the magnet piece, the bottom of the circular plate is fixedly connected with a first tension spring, and the bottom of the first tension spring is fixedly connected with the top of the bottom ring.

[0011] As a preferred technical scheme of the present application, the inner wall of the fixed ring is fixedly connected with a third tension spring, one end of the third tension spring away from the fixed ring is fixedly connected with a positioning convex rod, the shape and size of the convex surface of the positioning convex rod are matched with the shape and size of the inner wall of the limiting groove, the inner wall of the fixed ring near the top is slidably sleeved with a limiting rod, and the bottom of the limiting rod is tightly attached with the outer edge of the sealing ring through the inner wall of the tee pipe.

[0012] As a preferred technical scheme of the present application, the bypass regenerative turbine is used for boiler feed water temperature adjustment, the bypass regenerative turbine adopts an axial flow type or a centripetal type structure, a rotating speed controller for detecting rotating speed is arranged at the rotating shaft of the bypass regenerative turbine, and the signal output end of the rotating speed controller is electrically connected with the driving mechanism of the steam regulating valve of the bypass regenerative turbine through a cable.

[0013] As a preferred technical scheme of the present application, when the boiler load is reduced to the start-stop point, the bypass regenerative turbine diverts part of the main steam from the main regulating valve, the low-load bypass regulating valve introduces steam into the bypass regenerative turbine to expand and do work, the output shaft of the bypass regenerative turbine is coaxially connected with the input shaft of the variable-frequency generator through a rigid coupling, the variable-frequency generator is electrically connected with the input end of the high-power rectifier-inverter device through a high-voltage cable at the end away from the bypass regenerative turbine, the high-power rectifier-inverter device converts the non-fixed-frequency electric energy into electric energy of the same frequency as the power grid, the electric energy is transformed by a transformer and then connected to the plant power system, and the exhaust steam of the bypass regenerative turbine enters the feedwater temperature regulator, so that the gas is used to increase the boiler feedwater temperature.

[0014] As a preferred technical scheme of the present application, the outlet end of the main regulating valve away from the main valve is connected in communication with the steam inlet of the conventional steam turbine unit through a main steam pipeline, the conventional steam turbine unit realizes energy conversion by driving a conventional generator unit to supply energy to an auxiliary system, the exhaust steam outlet of the conventional steam turbine unit is connected in communication with the inlet of a condenser through an exhaust steam pipeline, the condensate water outlet of the condenser is connected in communication with the inlet of a shaft seal heater through a condensate water pipeline in sequence with the condensate water pump as an intermediate power component, the condensate water is heated by the shaft seal heater to absorb shaft seal leakage heat, the outlet of the shaft seal heater is connected in communication with the inlet of a low-pressure heater located downstream of the shaft seal heater, and the condensate water is further heated by the low-pressure heater; the outlet of the low-pressure heater is connected in communication with the inlet of a deaerator through a low-pressure heated water pipeline, the outlet of the deaerator is connected in communication with the inlet of a high-pressure heater through a pressurized water pipeline after being pressurized by a feedwater pump, the high-pressure heater heats the water to a predetermined temperature, the outlet pipeline of the high-pressure heater is connected in communication with a feedwater temperature regulator, a second bypass regenerative turbine is arranged in parallel on the side of the bypass regenerative turbine, and the two form parallel bypass regenerative paths.

[0015] The present application has the following beneficial effects: 1. The bypass regenerative turbine system for low-load feedwater heating of a thermal power unit is improved on the basis of an existing steam turbine steam cycle power generation system, a bypass regenerative turbine specially used for boiler feedwater temperature regulation is arranged, the turbine exhaust pressure and exhaust steam flow are controlled by changing the opening degree of the bypass regulating valve and the turbine rotating speed, the boiler feedwater temperature is always kept in an optimal temperature range, the steam work capacity is improved by using part of the non-throttling main steam during low-load constant-pressure operation, the coal consumption rate of the unit is reduced, and the overall energy-saving level is improved.

[0016] 2. This bypass heat recovery turbine system for low-load feedwater heating of thermal power units uses a tee pipe and an auxiliary pipe in conjunction, utilizing a main channel to supply main steam, and utilizing the main steam to propel a piston through the auxiliary pipe. When the piston moves to the connecting pipe and connects to the main channel through the auxiliary pipe, gas flows through the connecting pipe into the rotating groove, thereby driving the baffle to rotate. The auxiliary baffle then drives magnet plates one and two to attract each other, thereby driving the solenoid valve exhaust pipe to open. The baffle then drives the baffle to rotate, thereby assisting gas to supply steam to the bypass heat recovery turbine through the bypass channel, and the auxiliary device is automatically started and stopped according to the steam pressure.

[0017] 3. This bypass heat recovery turbine system, used for low-load feedwater heating in thermal power units, supplies air to the auxiliary ring through the solenoid valve tube, thereby pushing the circular plate downward. The circular plate then drives the magnet sheet to slide on the inner wall of the coil via a connecting rod. The electromagnetic damping generated by the coil and the magnet sheet assists the three-way pipe in reducing vibration, thereby avoiding valve vibration caused by flow fluctuations due to flow field turbulence, thereby ensuring stable operation of the device. When the circular plate moves downward, air is supplied to the interior of the fixed ring through the air guide tube, thereby assisting the downward movement of the limit rod, and then using the limit rod to squeeze and limit the sealing ring. The convex surface of the positioning protrusion is connected to the inner wall of the limit groove, thereby further ensuring the stable limit of the baffle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to the present invention; Figure 2 This is a schematic structural diagram of another embodiment of the bypass heat recovery turbine system for low-load feed water heating of a thermal power unit according to the present invention; Figure 3 This is a structural diagram of a low-load bypass regulating valve according to the present invention; Figure 4 This is a schematic diagram of the cross-sectional structure of the tee pipe of the present invention; Figure 5 This is a schematic diagram of the side cross-section structure of the tee pipe of the present invention; Figure 6 This is a schematic diagram of the cross-sectional structure of the auxiliary ring of the present invention; Figure 7 For the present invention Figure 6 A in the middle is an enlarged structural diagram; Figure 8 This is a schematic diagram of the cross-sectional structure of the baffle blade of the present invention; Figure 9 For the present invention Figure 8 The enlarged structural diagram at B in the middle; Figure 10 This is a schematic diagram of the piston structure of the present invention; Figure 11 Schematic diagram of the baffle structure of the present invention; Figure 12 Fig. 1 is a schematic diagram of the communication pipe structure of the present application; Figure 13 Fig. 2 is a schematic diagram of the positioning rod structure of the present application.

[0019] Fig. 1 is a schematic diagram of the communication pipe structure of the present application; 301, three-way pipe; 302, main channel; 303, bypass channel; 304, auxiliary pipe; 305, spring; 306, piston; 307, baffle; 308, rotating groove; 309, magnet plate one; 310, connecting pipe; 311, electromagnetic valve exhaust pipe; 312, magnet plate two; 313, rotating frame; 314, limiting groove; 315, baffle; 316, sealing ring; 317, fixed ring; 318, auxiliary ring; 319, communication pipe; 320, collar; 321, bottom ring; 322, coil; 323, magnet sheet; 324, connecting rod; 325, round plate; 326, air guide pipe; 327, first tension spring; 328, positioning wheel; 329, second tension spring; 330, compression ring; 331, rubber pad; 332, positioning rod; 333, third tension spring; 334, limiting rod. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0021] Embodiment one Please refer to Figure 1 - Figure 13 A bypass heat recovery turbine system for low load feed water heating of a thermal power unit, comprising the following modules: a boiler 1, a main steam valve 2, a low load bypass regulating valve 3, a main regulating valve 4, a bypass heat recovery turbine 5, and a feed water temperature regulator 11. The main steam outlet pipe of the boiler 1 is connected with the main steam valve 2, the outlet flange of the main steam valve 2 is connected to the inlet of the main regulating valve 4, and the steam after the main steam valve 2 enters the bypass heat recovery turbine 5 through the low-load bypass regulating valve 3, and the feed water temperature regulator 11 detects the feed water temperature entering the boiler 1 in real time; The boiler 1: converts the chemical energy of fuel into heat energy, and then generates high-temperature and high-pressure steam or hot water, and supplies the steam to the main steam valve 2; The main steam valve 2: controls the on-off and flow rate of the main steam discharged from the boiler 1, and cuts off the steam supply in an emergency to ensure system safety, supplies the main steam to the main regulating valve 4, and supplies part of the steam to the low-load bypass regulating valve 3; The low-load bypass regulating valve 3: ensures the stable operation of the steam power system under low-load, start-up and shutdown conditions, and supplies the steam to the bypass heat recovery turbine 5; The main regulating valve 4: ensures the stable and efficient operation of the equipment by dynamically adjusting the fluid parameters, and supplies the steam from the main steam valve 2 to the conventional steam turbine unit 12; The bypass heat recovery turbine 5: optimizes the heat recovery process, balances the steam distribution of the system and improves the energy utilization efficiency, uses the bypass steam supplied by the low-load bypass regulating valve 3 to do work, realizes energy recovery, and the exhaust steam of the bypass heat recovery turbine 5 enters the feed water temperature regulator 11 for heating the boiler 1 water. The bypass heat recovery turbine 5 is a steam turbine specially used for adjusting the feed water temperature of the boiler 1, which can adopt an axial flow or a centripetal structure, has the characteristics of adjustable rotating speed and fast start-stop.

[0022] The feed water temperature regulator 11: accurately controls the feed water temperature of the boiler 1 to be stable at the set value, optimizes the low coal consumption rate of the unit under the condition of maintaining the efficient operation of the boiler 1 flue gas denitration device SCR, determines the optimal boiler 1 feed water temperature range, and determines through thermal performance test or system simulation calculation.

[0023] In one preferred embodiment, the low load bypass regulating valve 3 comprises a three-way pipe 301, a main passage 302 is arranged in the center of the three-way pipe 301, and two ports of the main passage 302 are respectively connected with the main valve 2 and the main regulating valve 4 through pipelines, a bypass passage 303 is arranged at one end of the three-way pipe 301 away from the main passage 302, an auxiliary pipe 304 is fixedly sleeved on the side wall of the bypass passage 303, a piston 306 is slidably sleeved on the inner wall of the auxiliary pipe 304, a baffle 315 is rotatably sleeved on the inner wall of the bypass passage 303, a sealing ring 316 is fixedly sleeved on the outer edge of the baffle 315, the outer edge of the sealing ring 316 is tightly attached to the inner wall of the bypass passage 303, a spring 305 is fixedly connected to the side surface of the piston 306, and one end of the spring 305 away from the piston 306 is fixedly connected with the inner wall of the auxiliary pipe 304, the spring 305 is used in cooperation with the piston 306, so that the outer edge of the piston 306 assists in intercepting the outer edge of the connecting pipe 310, and the resistance of the piston 306 during movement in the pipeline is mainly the elastic force of the spring 305, the baffle 315 is used in cooperation with the sealing ring 316, so that the baffle 315 drives the sealing ring 316 to rotate, thereby assisting the main passage 302 and the bypass passage 303 to communicate.

[0024] In one preferred embodiment, the bottom of the baffle 315 is fixedly assembled with a rotating frame 313, the outer edge of the rotating frame 313 is rotatably sleeved with the inner wall of the auxiliary pipe 304, the outer edge of the rotating frame 313 is fixedly sleeved with a baffle leaf 307, the bottom of the rotating frame 313 is fixedly assembled with a positioning wheel 328, the outer edge of the positioning wheel 328 is fixedly sleeved with a second tension spring 329, and one end of the second tension spring 329 away from the positioning wheel 328 is fixedly connected with the inner wall of the auxiliary pipe 304, the outer edge of the rotating frame 313 is provided with a limiting groove 314, the inner wall of the auxiliary pipe 304 is provided with a rotating groove 308, and the inner wall of the rotating groove 308 is rotatably sleeved with the outer edge of the baffle leaf 307, the second tension spring 329 is connected with the positioning wheel 328, so that when the steam is released, the second tension spring 329 drives the positioning wheel 328 to reset, and the positioning wheel 328 drives the baffle leaf 307 to reset through the baffle leaf 307.

[0025] In one preferred embodiment, the auxiliary pipe 304 is fixedly sleeved with a connecting pipe 310 on the inner wall of both sides, the inner wall of the baffle 307 is fixedly assembled with a magnet plate one 309, the outer edge of the magnet plate one 309 is rotatably connected with the inner wall of the rotating groove 308, the inner wall of the auxiliary pipe 304 is fixedly assembled with a magnet plate two 312, the side surface of the magnet plate one 309 and the magnet plate two 312 is adsorbed, the side surface of the magnet plate two 312 is fixedly assembled with a Hall sensor, the Hall sensor is electrically connected with the magnet plate two 312, the inner wall of the auxiliary pipe 304 is fixedly assembled with an electromagnetic valve exhaust pipe 311, the electromagnetic valve exhaust pipe 311 is electrically connected with the Hall sensor, through the cooperation of the magnet plate one 309 and the magnet plate two 312, when the magnet plate one 309 and the magnet plate two 312 are adsorbed, the Hall sensor controls the electromagnetic valve exhaust pipe 311 to open, and then the auxiliary gas is discharged outward through the electromagnetic valve exhaust pipe 311.

[0026] In one preferred embodiment, the outer edge of the three-way pipe 301 is fixedly sleeved with a fixed ring 317, the side surface of the fixed ring 317 is fixedly assembled with an auxiliary ring 318, the inner wall of the auxiliary ring 318 is fixedly assembled with a communication pipe 319, the outer edge of the communication pipe 319 is fixedly sleeved with a sleeve ring 320, the inner wall of the sleeve ring 320 is fixedly sleeved with a gas guide pipe 326, the outer edge of the gas guide pipe 326 is fixedly sleeved with the inner wall of the fixed ring 317, the inner wall of the communication pipe 319 is fixedly sleeved with a bottom ring 321, the bottom of the bottom ring 321 is fixedly assembled with a pressing ring 330, the bottom of the pressing ring 330 is fixedly assembled with a rubber pad 331, and the bottom of the rubber pad 331 is fixedly sleeved with the outer edge of the three-way pipe 301, through the cooperation of the pressing ring 330 and the rubber pad 331, when the bypass channel 303 is inhaled, the auxiliary three-way pipe 301 is damped.

[0027] In one preferred implementation, the inner wall of the communication pipe 319 is sleeved with a round plate 325, the inner wall of the round plate 325 is fixedly sleeved with a connecting rod 324, the bottom of the connecting rod 324 is fixedly assembled with a magnet piece 323, the inner wall of the bottom ring 321 is fixedly sleeved with a coil 322, the inner wall of the coil 322 is sleeved with the outer edge of the magnet piece 323, the bottom of the round plate 325 is fixedly connected with a tension spring 327, and the bottom of the tension spring 327 is fixedly connected with the top of the bottom ring 321. By using the coil 322 and the magnet piece 323 together, when the magnet piece 323 slides on the inner wall of the coil 322, the coil 322 generates electromagnetic damping on the magnet piece 323, thereby assisting in damping the tee pipe 301, and when the magnet piece 323 and the connecting rod 324 move with the round plate 325, the gas inside the auxiliary ring 318 pushes the round plate 325 downward, thereby adjusting the device steam volume, ensuring stable operation of the device, and when the round plate 325 moves downward to the gas inside the auxiliary ring 318 through the communication pipe 319, the sleeve ring 320 and the air guide pipe 326 to the inside of the fixed ring 317, the auxiliary positioning lug 332 and the limiting groove 314 are connected, further ensuring the stability of the baffle 315.

[0028] In one preferred implementation, the inner wall of the fixed ring 317 is fixedly connected with a tension spring 333, and the end of the tension spring 333 away from the fixed ring 317 is fixedly connected with a positioning lug 332, and the shape and size of the convex surface of the positioning lug 332 are matched with the shape and size of the inner wall of the limiting groove 314. The inner wall of the fixed ring 317 close to the top is sleeved with a limiting rod 334, and the bottom of the limiting rod 334 is in close contact with the outer edge of the sealing ring 316 through the inner wall of the tee pipe 301. By using the positioning lug 332 and the limiting groove 314 together, when the convex surface of the positioning lug 332 is connected with the inner wall of the limiting groove 314, the auxiliary rotating frame 313 is limited.

[0029] In one preferred implementation, the bypass heat recovery turbine 5 is used for boiler 1 feed water temperature adjustment, the bypass heat recovery turbine 5 adopts an axial flow type or a centripetal type structure, a rotating speed controller 10 for detecting rotating speed is arranged at the rotating shaft of the bypass heat recovery turbine 5, and the signal output end of the rotating speed controller 10 is electrically connected with the drive mechanism of the steam regulating valve of the bypass heat recovery turbine 5 through a cable.

[0030] In a preferred embodiment, when the boiler 1 load is reduced to the start-stop point, the bypass regenerative turbine 5 shunts part of the main steam from the main regulating valve 4, the low-load bypass regulating valve 3 introduces steam into the bypass regenerative turbine 5 to expand and do work, the output shaft of the bypass regenerative turbine 5 is coaxially connected to the input shaft of the variable-frequency generator 6 through a rigid coupling, the end of the variable-frequency generator 6 away from the bypass regenerative turbine 5 is electrically connected to the input end of the high-power rectifier-inverter device 7 through a high-voltage cable, the high-power rectifier-inverter device 7 converts the non-fixed-frequency electric energy into electric energy of the same frequency as the power grid, the electric energy is transformed by the transformer 8 and then connected to the plant power system 9, and the exhaust steam of the bypass regenerative turbine 5 enters the feedwater temperature regulator 11, so as to use the gas to increase the feedwater temperature of the boiler 1.

[0031] In a preferred embodiment, the main regulating valve 4 is connected to the steam inlet of the conventional turbine unit 12 through a main steam pipeline away from the outlet end of the main steam valve 2, the conventional turbine unit 12 converts energy through driving the conventional generator unit 13 to supply energy to the auxiliary system, the exhaust steam outlet of the conventional turbine unit 12 is connected to the inlet of the condenser 14 through an exhaust steam pipeline, the condensate outlet of the condenser 14 is connected to the inlet of the shaft seal heater 16 through a condensate pipeline with the condensate pump 15 as an intermediate power component, the condensate is heated by the shaft seal heater 16 to absorb shaft seal leakage heat, the outlet of the shaft seal heater 16 is connected to the inlet of the low-pressure heater 17 downstream thereof, and the condensate is further heated by the low-pressure heater 17. The outlet of the low-pressure heater 17 is connected to the inlet of the deaerator 18 through a low-pressure heated water pipeline, the outlet of the deaerator 18 is connected to the inlet of the high-pressure heater 20 through a pressurized water pipeline after being pressurized by the feedwater pump 19, and the high-pressure heater 20 heats the water to a predetermined temperature, and the outlet pipeline thereof is connected to the feedwater temperature regulator 11.

[0032] Working principle, when the boiler 1 load is reduced to the start-stop point, the bypass regenerative turbine 5 shunts part of the main steam from the main regulating valve 4; The main steam is supplied by the main channel 302, and the piston 306 is moved by the main steam passing through the auxiliary pipe 304 until the main channel 302 communicates with the rotating groove 308 through the auxiliary pipe 304 and the connecting pipe 310, the gas passes through the connecting pipe 310 to the inside of the rotating groove 308, thereby driving the baffle 307 to rotate, and then the baffle 307 drives the magnet plate one 309 and the magnet plate two 312 to be attracted, thereby driving the electromagnetic valve exhaust pipe 311 to open, so that the baffle 307 drives the baffle 315 to rotate, thereby assisting the steam supply to the bypass heat regenerative turbine 5 through the bypass channel 303, and the auxiliary device is self-started and stopped according to the steam pressure, the auxiliary ring 318 is supplied with gas through the electromagnetic valve exhaust pipe 311, thereby driving the circular plate 325 to move downward, and the circular plate 325 drives the magnet sheet 323 to slide in the inner wall of the coil 322 through the connecting rod 324, thereby generating electromagnetic damping of the three-way pipe 301 by the coil 322 and the magnet sheet 323, avoiding the valve vibration caused by the flow field turbulence and flow fluctuation, thereby ensuring the stable operation of the device, and when the circular plate 325 moves downward, the fixed ring 317 is supplied with gas through the air guide pipe 326, thereby assisting the limit rod 334 to move downward, and then the limit rod 334 extrudes and limits the sealing ring 316, and the convex surface of the positioning convex rod 332 is connected with the inner wall of the limiting groove 314, thereby further ensuring the stable limiting of the baffle 315, and assisting the low-load bypass regulating valve 3 to be self-started and stopped, and further ensuring the stable limiting of the baffle 315 while avoiding the valve vibration caused by the flow field turbulence; The bypass heat regenerative turbine 5 directly drives the variable frequency generator 6 to generate non-fixed frequency electric energy, and then the high-power rectifier-inverter device 7 converts the non-fixed frequency electric energy into electric energy with the same frequency as the power grid, and the electric energy is connected to the plant power system 9 after being transformed by the transformer 8. The exhaust steam of the bypass heat regenerative turbine 5 enters the feedwater temperature regulator 11 to increase the feedwater temperature of the boiler 1, ensure the normal operation of the boiler 1 flue gas denitration device (SCR), and reduce the coal consumption of the boiler 1. When the load is further reduced, the low-load bypass regulating valve 3 is gradually opened, and the speed of the bypass heat regenerative turbine 5 is gradually increased by the speed controller 10, so that the feedwater temperature of the boiler 1 is always in the set range; When the load of the boiler 1 increases and is not higher than the start-stop point, the low-load bypass regulating valve 3 is gradually closed, and the speed of the bypass heat regenerative turbine 5 is gradually reduced by the speed controller 10, until the load of the boiler 1 increases to the start-stop point, at which time the low-load bypass regulating valve 3 is closed, the bypass heat regenerative turbine 5 is stopped and is in a heat preservation state, and waits for the next start; The bypass heat recovery turbine 5 is arranged for regulating the feed water temperature of the boiler 1. The turbine exhaust pressure and exhaust steam flow are controlled by changing the opening of the bypass regulating valve and the turbine speed, so that the feed water temperature of the boiler 1 is always in the optimum temperature range. The steam work capacity is improved by using part of the throttle-free main steam at low load constant pressure operation, the coal consumption rate of the unit is reduced, and the overall energy saving level is improved.

[0033] Embodiment two The bypass heat recovery turbine 5 is arranged for regulating the feed water temperature of the boiler 1. The turbine exhaust pressure and exhaust steam flow are controlled by changing the opening of the bypass regulating valve and the turbine speed, so that the feed water temperature of the boiler 1 is always in the optimum temperature range. The steam work capacity is improved by using part of the throttle-free main steam at low load constant pressure operation, the coal consumption rate of the unit is reduced, and the overall energy saving level is improved.

[0034] It should be noted that the relative terms such as first and second, and the like, are used herein solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0035] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made hereto without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. A bypass heat recovery turbine system for low-load feedwater heating of thermal power units, characterized in that: It includes the following modules: boiler (1), main steam valve (2), low-load bypass regulating valve (3), main regulating valve (4), bypass heat recovery turbine (5), feed water temperature regulator (11); The main steam outlet pipe of the boiler (1) is connected to the main steam valve (2), the outlet flange of the main steam valve (2) is connected to the inlet of the main regulating valve (4), and part of the steam after the main steam valve (2) enters the bypass heat recovery turbine (5) through the low-load bypass regulating valve (3), and the feed water temperature regulator (11) detects the feed water temperature entering the boiler (1) in real time; Boiler (1): Converts the chemical energy of fuel into thermal energy, thereby generating high-temperature and high-pressure steam or hot water, and supplies the steam to the main steam valve (2); Main steam valve (2): controls the on / off of the main steam discharged from the boiler (1), regulates the flow rate, and cuts off the steam supply in an emergency to ensure system safety. It supplies the main steam to the main regulating valve (4) and supplies part of the steam to the low-load bypass regulating valve (3); Low-load bypass regulating valve (3): ensures stable operation of the steam power system under low-load, startup, and shutdown conditions, and supplies steam to the bypass heat recovery turbine (5); Main regulating valve (4): ensures the equipment operates in a stable and efficient state by dynamically adjusting fluid parameters, connects to the main steam supplied by the main steam valve (2), and supplies steam to the conventional steam turbine unit (12); Bypass heat recovery turbine (5): optimizes the heat recovery process, balances the system steam distribution and improves energy utilization efficiency, uses the bypass steam supplied by the low-load bypass regulating valve (3) to perform work, and realizes energy recovery. The exhaust steam of the bypass heat recovery turbine (5) enters the feed water temperature regulator (11) and is used to heat the water of the boiler (1); Feed water temperature regulator (11): accurately controls the boiler (1) feed water temperature to stabilize it at the set value.

2. A bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 1, characterized in that: The low-load bypass regulating valve (3) comprises a three-way pipe (301), a main channel (302) is provided at the center of the three-way pipe (301), and two ports of the main channel (302) are respectively connected to the main steam valve (2) and the main regulating valve (4) through pipelines, a bypass channel (303) is provided at one end of the three-way pipe (301) away from the main channel (302), and an auxiliary pipe (304) is fixedly sleeved on the side wall of the bypass channel (303), and the auxiliary pipe (304) is connected to the main steam valve (2) and the main regulating valve (4). ) is slidably sleeved on the inner wall of the bypass channel (303), a baffle (315) is rotatably sleeved on the inner wall of the bypass channel (303), a sealing ring (316) is fixedly sleeved on the outer edge of the baffle (315), and the outer edge of the sealing ring (316) is tightly attached to the inner wall of the bypass channel (303), a spring (305) is fixedly connected to the side of the piston (306), and the end of the spring (305) away from the piston (306) is fixedly connected to the inner wall of the auxiliary tube (304).

3. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 2, characterized in that: The bottom of the baffle (315) is fixedly equipped with a rotating frame (313), the outer edge of the rotating frame (313) is rotatably sleeved with the inner wall of the auxiliary tube (304), the outer edge of the rotating frame (313) is fixedly sleeved with a baffle (307), the bottom of the rotating frame (313) is fixedly equipped with a positioning wheel (328), the outer edge of the positioning wheel (328) is fixedly sleeved with a second tension spring (329), and the end of the second tension spring (329) away from the positioning wheel (328) is fixedly connected to the inner wall of the auxiliary tube (304), the outer edge of the rotating frame (313) is provided with a limiting groove (314), the inner wall of the auxiliary tube (304) is provided with a rotating groove (308), and the inner wall of the rotating groove (308) is rotatably sleeved with the outer edge of the baffle (307).

4. A bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 3, characterized in that: The inner walls of the auxiliary tube (304) near both sides are fixedly sleeved with a connecting tube (310), the inner wall of the baffle (307) is fixedly equipped with a magnet plate 1 (309), and the outer edge of the magnet plate 1 (309) is rotatably connected to the inner wall of the rotating groove (308), the inner wall of the auxiliary tube (304) is fixedly equipped with a magnet plate 2 (312), the magnet plate 1 (309) and the adjacent side surfaces of the magnet plate 2 (312) are adsorbed, the side surface of the magnet plate 2 (312) is fixedly equipped with a Hall sensor, and the Hall sensor is electrically connected to the magnet plate 2 (312), the inner wall of the auxiliary tube (304) is fixedly equipped with an electromagnetic valve exhaust pipe (311), and the electromagnetic valve exhaust pipe (311) is electrically connected to the Hall sensor.

5. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 2, characterized in that: The outer edge of the three-way pipe (301) is fixedly sleeved with a fixing ring (317), the side of the fixing ring (317) is fixedly assembled with an auxiliary ring (318), the inner wall of the auxiliary ring (318) is fixedly assembled with a connecting pipe (319), the outer edge of the connecting pipe (319) is fixedly sleeved with a collar (320), the inner wall of the collar (320) is fixedly sleeved with an air guide pipe (326), and the outer edge of the air guide pipe (326) is fixedly sleeved with the inner wall of the fixing ring (317), the inner wall of the connecting pipe (319) is fixedly sleeved with a bottom ring (321), the bottom of the bottom ring (321) is fixedly assembled with a pressure ring (330), the bottom of the pressure ring (330) is fixedly assembled with a rubber pad (331), and the bottom of the rubber pad (331) is fixedly sleeved with the outer edge of the three-way pipe (301).

6. A bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 5, characterized in that: The inner wall of the connecting tube (319) is slidably connected to a circular plate (325), the inner wall of the circular plate (325) is fixedly connected to a connecting rod (324), the bottom of the connecting rod (324) is fixedly equipped with a magnet sheet (323), the inner wall of the bottom ring (321) is fixedly connected to a coil (322), and the inner wall of the coil (322) is slidably connected to the outer edge of the magnet sheet (323), the bottom of the circular plate (325) is fixedly connected to a tension spring (327), and the bottom of the tension spring (327) is fixedly connected to the top of the bottom ring (321).

7. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 5, characterized in that: The inner wall of the fixing ring (317) is fixedly connected to a tension spring three (333), and one end of the tension spring three (333) away from the fixing ring (317) is fixedly connected to a positioning protrusion (332), and the shape and size of the convex surface of the positioning protrusion (332) are adapted to the shape and size of the inner wall of the limiting groove (314). The inner wall of the fixing ring (317) near the top is slidably sleeved on the limiting rod (334), and the bottom of the limiting rod (334) passes through the inner wall of the three-way pipe (301) and is tightly attached to the outer edge of the sealing ring (316).

8. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 1, characterized in that: The bypass heat recovery turbine (5) is used for regulating the feed water temperature of the boiler (1). The bypass heat recovery turbine (5) adopts an axial flow or centripetal structure. A speed controller (10) for detecting the speed is provided at the rotating shaft of the bypass heat recovery turbine (5), and the signal output end of the speed controller (10) is electrically connected to the driving mechanism of the steam regulating valve of the bypass heat recovery turbine (5) through a cable.

9. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 1, characterized in that: When the load of the boiler (1) is reduced to the start-stop point, the bypass heat recovery turbine (5) diverts part of the main steam from the main regulating valve (4), and the low-load bypass regulating valve (3) introduces steam into the bypass heat recovery turbine (5) to expand and perform work. The output shaft of the bypass heat recovery turbine (5) is coaxially connected to the input shaft of the variable frequency generator (6) through a rigid coupling. The end of the variable frequency generator (6) away from the bypass heat recovery turbine (5) is electrically connected to the input end of the high-power rectifier-inverter device (7) through a high-voltage cable, and the high-power rectifier-inverter device (7) converts the non-constant frequency electric energy into electric energy with the same frequency as the power grid, and is connected to the plant power system (9) after being transformed by the transformer (8). The exhaust steam of the bypass heat recovery turbine (5) enters the feed water temperature regulator (11), so that the gas is used to increase the feed water temperature of the boiler (1).

10. The bypass heat recovery turbine system for low-load feedwater heating of a thermal power unit according to claim 1, characterized in that: The outlet end of the main regulating valve (4) away from the main steam valve (2) is connected to the steam inlet of the conventional steam turbine unit (12) through a main steam pipe. The conventional steam turbine unit (12) realizes energy conversion by driving the conventional generator unit (13) to supply energy to the auxiliary system. The exhaust steam outlet of the conventional steam turbine unit (12) is connected to the inlet of the condenser (14) through an exhaust steam pipe. The condensate outlet of the condenser (14) and the inlet of the shaft seal heater (16) are connected in sequence and communicated through the condensate pipe with the condensate pump (15) as the intermediate power component. After the condensate absorbs the heat of the shaft seal steam leakage through the shaft seal heater (16), the outlet of the shaft seal heater (16) is connected to the inlet of the low-pressure heater (17) located downstream thereof, and the condensate is further heated by the low-pressure heater (17). The outlet of the low-pressure heater (17) is connected to the inlet of the deaerator (18) through a low-pressure heated water pipeline. The outlet of the deaerator (18) is pressurized by the feed water pump (19) and then connected to the inlet of the high-pressure heater (20) through a pressurized water pipeline. After the high-pressure heater (20) heats the water to a predetermined temperature, its outlet pipeline is connected to the feed water temperature regulator (11). A second bypass heat recovery turbine (21) is arranged in parallel on the side of the bypass heat recovery turbine (5), and the two form a parallel bypass heat recovery path.

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