A low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit

Abstract

The application discloses a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooling unit, which comprises a medium-pressure cylinder, a low-pressure cylinder, a flash tank and a jet component, wherein the steam inlet end of the low-pressure cylinder is connected with the steam outlet end of the medium-pressure cylinder through a low-pressure steam pipe, a first valve body is arranged on the low-pressure steam pipe, a heat supply steam extraction pipe is also connected with the low-pressure steam pipe, the heat supply steam extraction pipe is located on the side of the first valve body close to the medium-pressure cylinder, the steam outlet end of the heat supply steam extraction pipe is connected with the flash tank, and the steam outlet end of the flash tank is connected with the jet component.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat supply, in particular to a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit. BACKGROUND

[0002] The ultra-supercritical air-cooled unit is a high-efficiency and low-emission power generation equipment, which adopts the combination of ultra-supercritical technology and air-cooling technology to greatly improve the power generation efficiency and environmental protection level of coal-fired power plants.

[0003] Among them, the ultra-supercritical technology refers to increasing the pressure of the boiler to the limit, so that the boiling point of water is increased to more than 374 degrees Celsius, thereby increasing the steam temperature and pressure, and increasing the power generation efficiency of the steam turbine, wherein the steam turbine includes a medium-pressure cylinder and a low-pressure cylinder, when the high-temperature and high-pressure steam passes through the medium-pressure cylinder and the low-pressure cylinder in turn, the blades therein can be driven to rotate to drive the shaft body to rotate, thereby driving the generator to rotate to realize power generation, and then part of the discharged steam can be treated for heat supply, in this process, how to realize peak regulation and heat supply and how to stably supply heat become the research focus.

[0004] Therefore, it is necessary to provide a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit to solve the problems raised in the background. SUMMARY

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit, comprising: a medium-pressure cylinder, a low-pressure cylinder, a flash tank and a jet assembly, wherein the steam inlet end of the low-pressure cylinder is connected with the steam outlet end of the medium-pressure cylinder through a low-pressure steam pipe, a first valve body is arranged on the low-pressure steam pipe, a heat supply steam extraction pipe is also connected with the low-pressure steam pipe, the heat supply steam extraction pipe is located on the side of the first valve body close to the medium-pressure cylinder, the steam outlet end of the heat supply steam extraction pipe is connected with the flash tank, and the steam outlet end of the flash tank is connected with the jet assembly.

[0006] Further, as a preferred, a third valve body is arranged on the heat supply steam extraction pipe, the third valve body is used for adjusting the flow size of the steam, and first cut-off valves are further arranged on the two sides of the third valve body.

[0007] Further, as a preferred, the steam inlet end of the low-pressure cylinder is also connected with the steam outlet end of the medium-pressure cylinder through a bypass pipe, a second valve body is arranged on the bypass pipe for adjusting the flow size of the steam, and second cut-off valves are further arranged on the two sides of the second valve body.

[0008] Further, as preferred, the jet flow assembly has a first gas inlet end, a second gas inlet end and a mixed gas outlet end, wherein the second gas inlet end is provided with high-temperature and high-pressure steam from an external high-pressure steam device, and the first gas inlet end is provided with a low-pressure steam inlet assembly connected to the steam outlet end of the flash tank.

[0009] Further, as preferred, the jet flow assembly includes a high-pressure steam cylinder and an inner cylinder, wherein one side of the high-pressure steam cylinder is the second gas inlet end, the other side is the mixed gas outlet end, the bottom of the high-pressure steam cylinder is the first gas inlet end, the second gas inlet end of the high-pressure steam cylinder extends inwardly and forms a nozzle, the inner cylinder is coaxially embedded in the high-pressure steam cylinder, and there is a gap between the inner cylinder and the high-pressure steam cylinder, the gap of the end of the inner cylinder close to the nozzle is sleeved on the outside of the nozzle, and the inside of the inner cylinder further forms a mixing part and an expansion part in sequence.

[0010] Further, as preferred, the low-pressure steam inlet assembly includes a mounting cylinder, a piston seat, a side hole and a communication pipe, wherein the mounting cylinder is fixed below the high-pressure steam cylinder, the mounting cylinder has a second chamber, the top of the second chamber is communicated with the first gas inlet end through the communication pipe, the bottom of the second chamber is open for communication with the steam outlet end of the flash tank, a first spring is connected between the second chamber and the piston seat, the piston seat is sealingly and slidingly arranged in the first chamber, a through hole is formed in the middle of the piston seat, a plurality of side holes are formed in the mounting cylinder and communicated with the first chamber, the side holes are collected on a collection pipe, the collection pipe is communicated with the communication pipe, in the initial stage, the side holes are located above the piston seat, and when the steam pressure supplied by the flash tank is lower than the threshold value, the piston seat remains below the side holes.

[0011] Further, as preferred, the outside of the mounting cylinder is sleeved with a connecting cylinder, the inside of the connecting cylinder is symmetrically fixed with a limiting cylinder, a sliding rod is slidingly connected in the limiting cylinder, a plug body is arranged at the right end of the sliding rod, a second spring is connected between the plug body and the corresponding limiting cylinder, the plug body is powered by a power pipe, the power pipe is supplied with liquid by an adaptive piece, the adaptive piece is located at the mixed gas outlet end of the jet flow assembly, a stopper is fixed on the sliding rod for blocking the through hole, in the initial stage, the stopper is located on the left side of the through hole and partially blocks the through hole.

[0012] Further, as preferred, the adaptive piece includes a heat-conducting ball, a heat-insulating bag is arranged in the gap of the heat-conducting ball, the heat-insulating bag and the heat-conducting ball are filled with a self-expanding liquid, the inside of the heat-insulating bag is filled with a driving liquid, and the heat-insulating bag is communicated with the power pipe.

[0013] Further, as preferred, the mounting cylinder also has a first chamber, and a positioning seat for positioning the communication pipe is fixed in the first chamber.

[0014] Further, as preferred, a first sealing ring is arranged between the communicating pipe and the second chamber, and a second sealing ring is arranged between the communicating pipe and the first chamber, and the first sealing ring and the second sealing ring are in sealing contact.

[0015] Compared with the prior art, the application provides a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit, which has the following beneficial effects:

[0016] In the embodiment of the application, the low-pressure cylinder zero-output heat supply technology is adopted, that is, all the steam inlets of the low-pressure cylinder of the steam turbine are cut off in the heat supply season, and only a small flow of steam is additionally connected to cool the low-pressure cylinder, so that the low-pressure cylinder is operated in an idle mode under high vacuum conditions, thereby improving the heat supply capacity and peak regulation capacity of the unit.

[0017] In the embodiment of the application, the low-pressure steam inlet assembly can adapt to the inlet pressure from the flash tank to ensure the safety of heat supply, and through the cooperation of the self-adaptive piece and the stopper, the inlet steam flow from the flash tank can be adjusted to make the output steam temperature tend to the threshold temperature, that is, the stability of the output steam temperature is maintained. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a structural schematic diagram of a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit;

[0019] Figure 2 FIG. 2 is a partial enlarged structural schematic diagram of the low-pressure cylinder zero-output heat supply device for the ultra-supercritical air-cooled unit; Figure 1

[0020] Figure 3 FIG. 3 is a structural schematic diagram of a self-adaptive piece in the low-pressure cylinder zero-output heat supply device for the ultra-supercritical air-cooled unit;

[0021] In the figure: 1, medium-pressure cylinder; 2, low-pressure cylinder; 3, low-pressure steam pipe; 4, first valve body; 5, heat supply extraction pipe; 6, bypass pipe; 7, second valve body; 8, third valve body; 9, flash tank; 10, high-pressure steam cylinder; 11, nozzle; 12, inner cylinder; 13, expansion part; 14, mixing part; 15, connecting cylinder; 16, mounting cylinder; 17, first chamber; 18, second chamber; 19, first spring; 20, piston seat; 21, through hole; 22, stopper; 23, sliding rod; 24, limiting cylinder; 25, second spring; 26, power pipe; 27, self-adaptive piece; 28, bypass hole; 29, collecting pipe; 30, communicating pipe; 31, positioning seat; 32, first sealing ring; 33, second sealing ring; 271, heat-conducting ball; 272, self-expanding liquid; 273, heat-insulating bag; 274, driving liquid. DETAILED DESCRIPTION

[0022] Please refer to Figures 1-3 ​The embodiment of the present application provides a low-pressure cylinder zero-output heat supply device for an ultra-supercritical air-cooled unit, which comprises a medium-pressure cylinder 1, a low-pressure cylinder 2, a flash tank 9 and a jet assembly, wherein the steam inlet end of the low-pressure cylinder 2 is connected with the steam outlet end of the medium-pressure cylinder 1 through a low-pressure steam pipe 3, a first valve body 4 is arranged on the low-pressure steam pipe 3, a heat supply steam extraction pipe 5 is also connected with the low-pressure steam pipe 3, the heat supply steam extraction pipe 5 is located on the side of the first valve body 4 close to the medium-pressure cylinder 1, the steam outlet end of the heat supply steam extraction pipe 5 is connected with the flash tank 9, and the steam outlet end of the flash tank 9 is connected with the jet assembly.

[0023] A third valve body 8 is arranged on the heat supply steam extraction pipe 5, the third valve body 8 is used for adjusting the flow size of steam, and first cut-off valves are arranged on the two sides of the third valve body 8.

[0024] The steam inlet end of the low-pressure cylinder 2 is also connected with the steam outlet end of the medium-pressure cylinder 1 through a bypass pipe 6, a second valve body 7 is arranged on the bypass pipe 6 and used for adjusting the flow size of steam, and second cut-off valves are arranged on the two sides of the second valve body 7.

[0025] In the embodiment, the low-pressure cylinder zero-output heat supply technology is adopted, that is, in the heat supply season, the steam inlet of the low-pressure cylinder of the steam turbine is completely cut off, only a small flow of steam is additionally connected to cool the low-pressure cylinder, the low-pressure cylinder is operated in the condition of high vacuum and idling, and therefore the heat supply capacity and the peak regulation capacity of the unit are improved.

[0026] In order to meet the safe and stable operation of the unit in the low-pressure cylinder zero-output state, a safety monitoring system can be additionally arranged to guarantee the safety of the blade in the cut-off cylinder state, a bypass pipe 6 is arranged between the medium-pressure cylinder and the low-pressure cylinder, a second valve body 7 is arranged on the bypass pipe 6 and used for adjusting the flow size of steam, second cut-off valves are arranged on the two sides of the second valve body 7, and the second valve body 7 is convenient for maintenance. Therefore, the cooling flow can be introduced into the low-pressure cylinder from the medium-pressure cylinder in the closed state of the first valve body, and the overheat of the low-pressure cylinder is prevented.

[0027] In addition, in actual implementation, the low-pressure cylinder zero-output heat supply technology needs to adopt optimized last-stage and penultimate-stage blades, so that the blades can meet the strength requirement under high temperature and have good water erosion resistance.

[0028] In addition, the possible flutter point of the blade under small flow needs to be accurately analyzed, and attention should be paid to avoiding the flutter point during operation.

[0029] In the embodiment, the jet flow assembly has a first gas inlet end, a second gas inlet end and a mixed gas outlet end, wherein the second gas inlet end is provided with high-temperature and high-pressure steam from an external high-pressure steam device, the first gas inlet end is provided with a low-pressure steam inlet assembly connected with the steam outlet end of the flash tank 9, and the high-temperature and high-pressure steam is used to provide power for steam supply of the flash tank 9. Specifically, the jet flow assembly comprises a high-pressure steam cylinder 10 and an inner cylinder 12, wherein one side of the high-pressure steam cylinder 10 is the second gas inlet end, the other side is the mixed gas outlet end, the bottom of the high-pressure steam cylinder 10 is the first gas inlet end, the second gas inlet end of the high-pressure steam cylinder 10 extends inwardly and forms a nozzle 11, the inner cylinder 12 is coaxially embedded in the high-pressure steam cylinder 10, and there is a gap between the inner cylinder 12 and the high-pressure steam cylinder 10, one end of the inner cylinder 12 close to the nozzle 11 is sleeved on the outside of the nozzle 11, and the inside of the inner cylinder 12 further forms a mixing part 14 and an expansion part 13 in sequence.

[0030] Therefore, when the high-temperature and high-pressure steam passes through the nozzle in the implementation, the pressure energy is converted into kinetic energy, a low-pressure area is formed behind the nozzle, thereby sucking the low-pressure steam in the gap between the high-pressure steam cylinder 10 and the inner cylinder 12, and after mixing in the mixing part 14, the kinetic energy is converted into pressure energy through the expansion part, and then discharged from the mixed gas outlet end.

[0031] In the embodiment, the low-pressure steam inlet assembly comprises a mounting cylinder 16, a piston seat 20, a plurality of side holes 28 and a communication pipe 30, wherein the mounting cylinder 16 is fixed below the high-pressure steam cylinder 10, the mounting cylinder 16 has a second chamber 18, the top of the second chamber 18 is communicated with the first gas inlet end through the communication pipe 30, the bottom of the second chamber 18 is open for communication with the steam outlet end of the flash tank 9, the first spring 19 is connected with the piston seat 20 in the second chamber 18, the piston seat 20 is sealingly and slidingly arranged in the first chamber 17, a through hole 21 is formed in the middle of the piston seat 20, a plurality of side holes 28 are further arranged on the mounting cylinder 16 and communicated with the first chamber 17, the side holes 28 are gathered on a gathering pipe 29, the gathering pipe 29 is communicated with the communication pipe 30, in the initial stage, the side holes 28 are located above the piston seat 20, when the steam pressure supplied by the flash tank 9 is lower than a threshold value, the piston seat 20 remains below the side holes, and when the steam pressure supplied by the flash tank 9 is higher than the threshold value, the piston seat 20 is driven upward by the air pressure, so that part of the steam can be discharged from part of the side holes 28, and the greater the air pressure, the greater the upward moving distance of the piston seat, and the more side holes that can discharge steam, thereby improving the discharge speed of the steam in the flash tank 9. Such arrangement can cope with the sudden situation that the internal air pressure of the flash tank 9 suddenly increases.

[0032] In addition, the outside of the mounting cylinder 16 is sleeved with a connecting cylinder 15, the inside of the connecting cylinder 15 is symmetrically fixed with a limiting cylinder 24, the limiting cylinder 24 is slidably connected with a sliding rod 23, the right end of the sliding rod 23 is provided with a plug, the plug is connected with the corresponding limiting cylinder through a second spring 25, the plug is powered by a power pipe 26, the power pipe 26 is supplied with liquid by an adaptive piece 27, the adaptive piece 27 is located at the mixed steam outlet end of the jet assembly, the sliding rod 23 is fixed with a stopper 22 for plugging the through hole 21, in the initial stage, the stopper 22 is located at the left side of the through hole 21 and semi-plugs the through hole 21.

[0033] In addition, the adaptive piece 27 comprises a heat-conducting ball 271, the inside gap of the heat-conducting ball 271 is provided with a heat insulation bag 273, the heat insulation bag 273 and the heat-conducting ball 271 are filled with a self-expanding liquid 272, the inside of the heat insulation bag 273 is filled with a driving liquid 274, and the heat insulation bag 273 is also communicated with the power pipe 26.

[0034] The object reaches thermal equilibrium in the instant of contact, that is, the temperature of the two objects is the same, therefore, the surface temperature of the heat-conducting ball is consistent with the steam temperature, in addition, the temperature is the average kinetic energy of the particles in the object, for example, when the steam temperature rises, the kinetic energy of the particles increases, the heat-conducting ball is heated, therefore, the surface temperature of the heat-conducting ball changes with the change of the steam temperature. Therefore, when the output steam temperature is high, the self-expanding liquid 272 is further expanded, so as to drive the heat insulation bag 273 to be further squeezed, and the driving liquid in the heat insulation bag 273 is further introduced into the right limiting cylinder 24 through the power pipe 26, so as to drive the stopper 22 to move leftwards through the sliding rod 23, so that more steam in the flash tank 9 can enter the high-pressure steam cylinder to mix with the high-pressure and high-temperature steam, so that the output steam temperature tends to the threshold temperature.

[0035] When the output steam temperature is low, the expansion degree of the self-expanding liquid 272 decreases, the pressure of the driving liquid introduced into the right limiting cylinder 24 is small, under the action of the second spring, the sliding rod 23 drives the stopper 22 to move rightwards, so that less steam in the flash tank 9 can enter the high-pressure steam cylinder to mix with the high-pressure and high-temperature steam, so that the output steam temperature tends to the threshold temperature.

[0036] As a preferred embodiment, the mounting cylinder 16 further has a first cavity 17, and the first cavity 17 is fixed with a positioning seat 31 for positioning the communication pipe 30.

[0037] As a preferred embodiment, the communication pipe 30 is provided with a first sealing ring 32 between the communication pipe 30 and the second cavity, and the communication pipe 30 is provided with a second sealing ring 33 between the communication pipe 30 and the first cavity, and the first sealing ring 32 and the second sealing ring 33 are in sealing contact.

[0038] The above merely provides the preferred embodiment of the present application, and the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes according to the technical scheme and the inventive concept of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A low-pressure cylinder zero-output heating device for ultra-supercritical air-cooled units, comprising: The system comprises a medium-pressure cylinder, a low-pressure cylinder, a flash tank, and a jet assembly. The steam inlet of the low-pressure cylinder is connected to the steam outlet of the medium-pressure cylinder via a low-pressure steam pipe. The system is characterized in that: a first valve body is provided on the low-pressure steam pipe, and a heating extraction steam pipe is also connected to the low-pressure steam pipe. The heating extraction steam pipe is located on the side of the first valve body near the medium-pressure cylinder. The steam outlet of the heating extraction steam pipe is connected to the flash tank, and the steam outlet of the flash tank is connected to the jet assembly. The jet assembly has a first air inlet end, a second air inlet end, and a mixed steam outlet end. The second air inlet end is supplied with high-temperature and high-pressure steam by an external high-pressure steam device. The first air inlet end is equipped with a low-pressure steam inlet assembly, which is connected to the steam outlet end of the flash tank. The jet assembly includes a high-pressure steam cylinder and an inner cylinder. One side of the high-pressure steam cylinder is a second air inlet, and the other side is a mixing steam outlet. The bottom of the high-pressure steam cylinder is a first air inlet. The second air inlet of the high-pressure steam cylinder extends inward to form a nozzle. The inner cylinder is coaxially embedded in the high-pressure steam cylinder, and there is a gap between the inner cylinder and the high-pressure steam cylinder. The end of the inner cylinder near the nozzle is fitted with the nozzle outside the gap. The inner cylinder also has a mixing section and an expansion section formed in sequence inside. The low-pressure steam inlet assembly includes an installation cylinder, a piston seat, bypass holes, and a connecting pipe. The installation cylinder is fixed below the high-pressure steam cylinder and has a second chamber. The top of the second chamber is connected to the first air inlet end via the connecting pipe, and the bottom of the second chamber is open for connection to the air outlet end of the flash tank. The second chamber is connected to the piston seat via a first spring. The piston seat is slidably and sealed in the first chamber and has a through hole in the middle. The installation cylinder also has multiple bypass holes connected to the first chamber. The bypass holes converge onto a collection pipe, which is connected to the connecting pipe. Initially, the bypass holes are located above the piston seat, and when the steam pressure supplied by the flash tank is lower than the threshold, the piston seat remains below the bypass holes. The mounting cylinder is fitted with a connecting cylinder on the outside. The connecting cylinder is symmetrically fixed with a limiting cylinder inside. A sliding rod is slidably connected in the limiting cylinder. A plug is provided at the right end of the sliding rod. A second spring is connected between the plug and the corresponding limiting cylinder. The plug is powered by a power pipe. The power pipe is supplied with liquid by an adaptive component. The adaptive component is located at the mixing and steam outlet end of the jet assembly. A stopper is fixed on the sliding rod to block the through hole. In the initial stage, the stopper is located on the left side of the through hole and partially blocks the through hole. The adaptive component includes a heat-conducting ball, an insulation bladder is provided in the internal gap of the heat-conducting ball, a self-expanding fluid is filled between the insulation bladder and the heat-conducting ball, the interior of the insulation bladder is filled with driving fluid, and the insulation bladder is also connected to the power pipe.

2. The low-pressure cylinder zero-output heating device for ultra-supercritical air-cooled units according to claim 1, characterized in that: A third valve body is installed on the heating extraction pipe. The third valve body is used to regulate the steam flow rate. First shut-off valves are also installed on both sides of the third valve body.

3. A zero-output heating device for a low-pressure cylinder in an ultra-supercritical air-cooled unit according to claim 1, characterized in that: The steam inlet of the low-pressure cylinder is connected to the steam outlet of the intermediate-pressure cylinder via a bypass pipe. A second valve body is installed on the bypass pipe to regulate the steam flow rate. Second shut-off valves are also installed on both sides of the second valve body.

4. A zero-output heating device for a low-pressure cylinder in an ultra-supercritical air-cooled unit according to claim 1, characterized in that: The mounting cylinder also has a first chamber in which a positioning seat for positioning the connecting pipe is fixed.

5. A low-pressure cylinder zero-output heating device for ultra-supercritical air-cooled units according to claim 4, characterized in that: A first sealing ring is provided between the connecting pipe and the second chamber, and a second sealing ring is provided between the connecting pipe and the first chamber, with the first sealing ring and the second sealing ring in sealed contact.

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