Steam jet type temperature reduction device and system and use method thereof

Abstract

The invention relates to a steam jet type desuperheater which comprises a steam jet type desuperheater, a cooling water atomization assembly, a power steam assembly and an exhaust port steam pipeline isolating valve. A steam end is arranged at one end of the steam jet type desuperheater, a discharge end is arranged at the other end of the steam jet type desuperheater, and a suction end is arranged close to the steam end; the steam end is connected with the power steam assembly, the suction end is connected with the cooling water atomization assembly, and the discharge end is connected with the discharge port steam pipeline isolation valve; a pipeline at the steam end of the steam jet type temperature reduction device is connected with a steam exhaust pipeline of the medium-pressure cylinder, the cooling water atomization device is connected with a demineralized water pipeline and a condensed water pipeline at an outlet of a condensed water pump, and the exhaust end of the steam jet type temperature reduction device is connected with the steam inlet end of the low-pressure cylinder; steam is extracted from a medium-pressure cylinder steam exhaust pipe through a desuperheater, negative pressure is formed in a pump after the steam passes through a nozzle to suck atomized cooling water, and the steam is mixed and boosted in the desuperheater to directly cool a low-pressure cylinder; the optimal atomized water parameter is obtained through design, and the cooling steam temperature of the low-pressure cylinder is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines in power plants, and in particular to a steam jet type temperature reducing device and a system and a use method thereof. Background Art

[0002] In recent years, with the strong support of national policies, my country's renewable energy power generation has achieved leapfrog development. In order to improve the consumption capacity of renewable energy, the flexible operation of thermal power units is imminent, and the steam turbines of coal-fired power plants will operate more frequently at extremely low loads. Cogeneration units often operate at zero output (cut off the low-pressure cylinder) during the heating season in order to extract more steam for heating needs.

[0003] When the low-pressure cylinder of a power plant is operating at zero output, only a small amount of cooling steam is retained to cool the low-pressure cylinder. The small volume flow operation causes the last-stage blades to blow. The temperature rise of the blowing will cause thermal stress deformation and allowable stress reduction of the flow equipment. Since the cooling steam uses middle-discharge steam, the temperature is relatively high; in order to obtain a better cooling effect for the low-pressure cylinder, the existing technology is mostly to cool the steam. At present, direct contact water spray desuperheaters are mainly used, which are mainly divided into vortex type, Venturi type and multi-hole nozzle type. These methods all have shortcomings:

[0004] 1. Water at the outlet of the desuperheater

[0005] During the desuperheating process, cooling water is sprayed in through the nozzle inside the desuperheater to form mist droplets that mix with the steam. The amount of cooling water is controlled by measuring the steam temperature downstream of the desuperheater. All direct contact desuperheaters must make the diameter of the sprayed cooling water droplets as small as possible to increase the surface area / volume ratio of the water. The larger the surface area / volume ratio of the water, the faster the water droplets evaporate and the faster the steam cools down. The process of making small water droplets is usually called "atomization", and the quality of atomization will directly affect the control performance of the desuperheating system.

[0006] 2. Difficulty in designing and arranging the downstream pipeline of the desuperheater

[0007] During the desuperheating process, the atomized water droplets need to mix with the steam, absorb heat and evaporate. Most of the desuperheating process does not occur inside the desuperheater, but in the downstream pipe of the desuperheater outlet. If the water droplets are not mixed well with the steam, they cannot effectively absorb heat from the superheated steam. Incomplete evaporation of the water droplets may cause water droplets to overflow downstream of the desuperheater. Not only can the desuperheater outlet temperature not be controlled, but the water droplets will enter the low-pressure cylinder with the steam, threatening the safety of the unit.

[0008] In order to ensure better evaporation of water droplets, a downstream pipeline of sufficient length is usually required to keep the water droplets suspended in the pipeline for as long as possible and maintain a relatively high flow rate. This places more requirements on the on-site layout of equipment and pipelines and is difficult.

[0009] 3. The mixing speed of steam and desuperheating water in the desuperheater cannot be significantly increased

[0010] Reducing the diameter of the desuperheater section can increase the mixing speed of steam and cooling water in the desuperheater, which helps to intensify the generation of turbulence. The violent turbulence will prolong the retention time of individual water particles in the desuperheater, making the heat exchange more sufficient. In addition to throttling, the increase in steam flow rate can also be achieved by the reasonable selection of pipe diameter. It should be noted that superheated steam with too high a speed will bring many serious problems. The steam speed entering the desuperheater is usually controlled at 40 to 60 m / s.

[0011] On the other hand, another way to reduce the exhaust temperature under low volume flow conditions is to use a large amount of low-pressure cylinder water spray. Since the root of the last-stage blade is in the steam vortex area, the sprayed water is easily sucked in, causing serious water erosion in the blade root area. If it is operated for a long time under this condition, it will bring serious safety hazards to the blades. Summary of the invention

[0012] In view of the above problems, a steam jet cooling device and a system and a use method thereof are proposed.

[0013] The technical solution of the present invention is: a steam jet type temperature reduction device, comprising a steam jet type temperature reducer, a cooling water atomization component, a power steam component, and a steam pipeline isolation valve at a discharge outlet;

[0014] The steam jet desuperheater has a steam end at one end, a discharge end at the other end, and a suction end near the steam end;

[0015] The steam end is connected to the power steam component, the suction end is connected to the cooling water atomization component, and the discharge end is connected to the discharge outlet steam pipeline isolation valve.

[0016] Preferably, the cooling water atomization assembly includes a cooling water atomization device, a cooling water regulating valve group, and an atomization water pipeline isolation valve; the cooling water atomization device is connected to the suction end through a pipeline, and the end of the cooling water atomization device away from the suction end is connected to the cooling water regulating valve group through a pipeline, and the end of the cooling water regulating valve group away from the cooling water atomization device is connected to the atomization water pipeline isolation valve through a pipeline.

[0017] Preferably, the pipeline between the cooling water regulating valve group and the atomizing water pipeline isolation valve is connected to the desalted water pipeline, and a desalted water isolation valve is provided on the desalted water pipeline.

[0018] Preferably, the motive steam assembly comprises a motive steam regulator and a motive steam line isolation valve;

[0019] The power steam regulator is connected to the steam end through a pipeline, and one end of the power steam regulator away from the steam end is connected to the power steam pipeline isolation valve through a pipeline.

[0020] Preferably, the pipeline between the power steam regulator and the power steam pipeline isolation valve connects the three-extraction steam pipeline and the four-extraction steam pipeline, a three-extraction steam isolation valve is provided on the three-extraction steam pipeline, and a four-extraction steam isolation valve is provided on the four-extraction steam pipeline.

[0021] A system including a steam jet type desuperheater comprises a high pressure cylinder, a medium pressure cylinder, a low pressure cylinder, a condenser, a condensate pump, and a steam jet type desuperheater;

[0022] The steam outlet of the high-pressure cylinder is connected to the steam inlet of the medium-pressure cylinder, the exhaust pipe on the other side of the medium-pressure cylinder is connected to the low-pressure cylinder, the exhaust pipe on the other side of the low-pressure cylinder is connected to the condenser, and the condensate pipe on the other side of the condenser is connected to the inlet of the condensate pump;

[0023] The pipeline of the power steam component away from the steam end is connected to the exhaust pipe of the medium-pressure cylinder, the end of the cooling water atomization component away from the suction end is connected to the condensate pipeline at the outlet of the condensate pump, and the end of the exhaust steam pipeline isolation valve away from the discharge end is connected to the steam inlet end of the low-pressure cylinder through a pipeline.

[0024] Preferably, a medium- and low-pressure connecting pipe butterfly valve is provided on the exhaust pipe between the medium-pressure cylinder and the low-pressure cylinder.

[0025] Preferably, an external steam supply pipeline is provided on the exhaust pipeline of the medium- and low-pressure connecting pipe butterfly valve away from the low-pressure cylinder side, and a medium-exhaust steam external steam supply isolation valve is provided on the external steam supply pipeline.

[0026] A method for using a system including a steam jet desuperheating device, comprising the following steps:

[0027] During the cylinder cutting process, the butterfly valves of the medium and low pressure connecting pipes are gradually closed, and the power steam pipeline isolation valve and the power steam regulator are opened at the same time; when the butterfly valves of the medium and low pressure connecting pipes are completely closed, the medium exhaust steam pressure increases. In order to ensure that the steam flow rate in the bypass steam pipeline does not exceed the limit, the opening of the power steam regulator is adjusted accordingly, and the steam jet cooling device effectively mixes the exhaust steam and cooling water from the medium pressure cylinder within this opening range, wherein the cooling water in the cooling water atomizing assembly is sucked into the steam jet cooling device, rapidly boils and vaporizes in the steam jet cooling device, mixes with the steam and effectively absorbs the heat of the steam to form superheated steam at a lower temperature, and the exhaust steam is connected to the low pressure cylinder as the low pressure cylinder cooling steam.

[0028] Furthermore, the cooling water is adjusted to the opening of the cooling water regulating valve group according to the exhaust temperature of the low-pressure cylinder, and the cooling steam temperature is adjusted by controlling the cooling water flow rate.

[0029] The beneficial effects of the present invention are as follows: a steam jet type desuperheating device and a system provided by the present invention have the following advantages: it can replace the existing low-pressure cylinder cooling steam system, only a small amount of heating steam is needed to be matched with atomized cooling water, water and steam are mixed and fully expanded in the desuperheater, and the outlet steam is superheated dry steam, without the risk of steam carrying water; in the early stage of steam-water mixing, since the high-temperature steam is ejected through the Rafale nozzle, its speed reaches supersonic speed, and the entrainment capacity of the low-temperature water mist is much greater than that of other mixing methods; in the steam-water mixing process, the shock wave effect is utilized to mix the atomized water and steam at a high speed and fully, and its effect is also much greater than that of other mixing methods; in the latter stage of the steam-water mixing, the expansion mixing is adopted to further enhance the mixing effect; the outlet steam temperature and superheat of the desuperheater are adjustable, and the cooling steam temperature can be reduced as low as possible, thereby effectively reducing the exhaust temperature of the low-pressure cylinder and protecting the safety of the low-pressure cylinder; the system structure is simple and easy to operate, and the optimal atomized water parameters can be obtained by design to reduce the cooling steam temperature of the low-pressure cylinder, improve the steam dryness, and protect the safety of the blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A three-dimensional diagram of the steam jet type temperature reduction device of the present invention;

[0031] Figure 2 The schematic diagram of the system including the steam jet desuperheater of the present invention is shown in FIG.

[0032] In the figure, the component names corresponding to the reference numerals are as follows:

[0033] 1. High-pressure cylinder; 2. Medium-pressure cylinder; 3. Low-pressure cylinder; 4. Condenser; 5. Condensate pump; 6. Steam jet desuperheater; 61. Steam jet desuperheater; 611. Steam end; 612. Suction end; 613. Discharge end; 62. Cooling water atomization assembly; 621. Cooling water atomization assembly; 622. Cooling water regulating valve group; 623. Isolation valve for atomizing water pipeline; 624. Desalted water isolation valve; 63. Power steam assembly; 631. Power steam regulator; 632. Power steam pipeline isolation valve; 633. Three-extraction steam isolation valve; 634. Four-extraction steam isolation valve; 64. Discharge outlet steam pipeline isolation valve; 7. Middle-exhaust steam external steam supply isolation valve; 8. Medium and low pressure connecting pipe butterfly valve. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0035] refer to Figure 1As shown, the embodiment of the present application discloses a steam jet type temperature reduction device and a system thereof, including a steam jet type temperature reducer 61, a cooling water atomization assembly 62, a power steam assembly 63, and a discharge outlet steam pipeline isolation valve 64;

[0036] The steam jet type desuperheater 61 has a steam end 611 at one end, a discharge end 613 at the other end, and a suction end 612 near the steam end 611;

[0037] The steam end 611 is connected to the power steam assembly 63, the suction end 612 is connected to the cooling water atomization assembly 62, and the discharge end 613 is connected to the discharge outlet steam pipeline isolation valve 64;

[0038] The cooling water atomization assembly 62 includes a cooling water atomization device 621, a cooling water regulating valve group 622, and an atomization water pipeline isolation valve 623;

[0039] The cooling water atomizing device 621 is connected to the suction end 612 through a pipeline, and one end of the cooling water atomizing device 621 away from the suction end 612 is connected to the cooling water regulating valve group 622 through a pipeline, and one end of the cooling water regulating valve group 622 away from the cooling water atomizing device 621 is connected to the atomizing water pipeline isolation valve 623 through a pipeline;

[0040] The pipeline between the cooling water regulating valve group 622 and the atomizing water pipeline isolation valve 623 is connected to the desalted water pipeline, and a desalted water isolation valve 624 is provided on the desalted water pipeline;

[0041] The suction end 612 of the steam jet desuperheater 61 is provided with two cooling water sources, one from condensed water and the other from desalted water;

[0042] The motive steam assembly 63 includes a motive steam regulator 631 and a motive steam pipeline isolation valve 632;

[0043] The power steam regulator 631 is connected to the steam end 611 through a pipeline, and one end of the power steam regulator 631 away from the steam end 611 is connected to the power steam pipeline isolation valve 632 through a pipeline.

[0044] The pipeline between the power steam regulator 631 and the power steam pipeline isolation valve 632 connects the three-extraction steam pipeline and the four-extraction steam pipeline. The three-extraction steam pipeline is provided with a three-extraction steam isolation valve 633, and the four-extraction steam pipeline is provided with a four-extraction steam isolation valve 634;

[0045] refer to Figure 2 As shown, the embodiment of the present application also discloses a system including a steam jet type temperature reduction device, including a high pressure cylinder 1, a medium pressure cylinder 2, a low pressure cylinder 3, a condenser 4, a condensate pump 5, and a steam jet type temperature reduction device 6;

[0046] The steam outlet of the high-pressure cylinder 1 is connected to the steam inlet of the medium-pressure cylinder 2, the exhaust pipe on the other side of the medium-pressure cylinder 2 is connected to the low-pressure cylinder 3, the exhaust pipe on the other side of the low-pressure cylinder 3 is connected to the condenser 4, and the condensate pipe on the other side of the condenser 4 is connected to the inlet of the condensate pump 5;

[0047] The pipeline of the power steam component 63 away from the steam end 611 is connected to the exhaust pipe of the medium pressure cylinder 2, the end of the cooling water atomization component 62 away from the suction end 612 is connected to the condensate pipeline of the condensate pump 5 outlet, and the end of the exhaust steam pipeline isolation valve 64 away from the discharge end 613 is connected to the steam inlet end of the low pressure cylinder 3 through a pipeline;

[0048] Specifically, one end of the power steam pipeline isolation valve 632 away from the power steam regulator 631 is connected to the exhaust pipe of the medium pressure cylinder 2 through a pipeline, and one end of the atomizing water pipeline isolation valve 623 away from the cooling water regulating valve group 622 is connected to the condensate pipeline at the outlet of the condensate pump 5 through a pipeline;

[0049] The cooling water atomizing assembly 62 can draw the cooling water into the steam jet type desuperheater 61, where the cooling water is rapidly boiled and vaporized and mixed with the steam and effectively absorbs the heat of the steam, and the discharged steam is connected to the low-pressure cylinder 3 as the low-pressure cylinder cooling steam; thereby providing low-temperature cooling steam for the low-pressure cylinder, and enhancing the cooling effect on the last two-stage blades of the low-pressure cylinder 3; the cooling water is adjusted to the opening of the cooling water regulating valve group 622 according to the exhaust steam temperature of the low-pressure cylinder 3, and the cooling steam temperature can be adjusted by controlling the cooling water flow rate;

[0050] On this basis, after the low-pressure cylinder 3 is transformed to zero output, a cooling steam bypass for the low-pressure cylinder 3 is set; in this example, a steam jet type temperature reduction device 6 is set in the thermal power unit with zero output transformation of the low-pressure cylinder 3 of the heating unit, replacing the common low-pressure cylinder cooling steam system for exhaust steam cooling in the low-pressure cylinder, and providing lower temperature superheated steam as low-pressure cylinder cooling steam; correspondingly, the steam jet type temperature reduction device 6 is used to effectively mix the exhaust steam from the medium-pressure cylinder 2 and the cooling water to generate superheated steam at a lower temperature to meet the cooling requirements of the low-pressure cylinder 3;

[0051] A medium- and low-pressure connecting pipe butterfly valve 8 is provided on the exhaust pipe between the medium-pressure cylinder 2 and the low-pressure cylinder 3;

[0052] An external steam supply pipeline is provided on the exhaust pipeline of the medium- and low-pressure connecting pipe butterfly valve 8 away from the low-pressure cylinder 3, and an external steam supply pipeline is provided on the external steam supply pipeline. The middle exhaust steam external steam supply isolation valve 7 is provided on the external steam supply pipeline; the steam jet type temperature reduction device 6 is connected to the exhaust pipeline of the medium-pressure cylinder 2 at a position between the medium-pressure cylinder 2 and the external steam supply pipeline;

[0053] The connection position of the pipeline between the steam jet type temperature reduction device 6 and the low pressure cylinder 3 is between the medium pressure cylinder 3 and the medium and low pressure connecting pipe butterfly valve 8;

[0054] The system structure according to this scheme is applied in the thermal power unit adopting the low-pressure cylinder zero-output system. A small amount of steam is extracted from the exhaust pipe of the intermediate-pressure cylinder 2 by the steam jet type temperature reduction device 6. After passing through the nozzle, a negative pressure is formed in the pump to suck the atomized cooling water, which is mixed and pressurized in the steam jet type temperature reduction device 6. At the same time, the steam is sent to the steam inlet pipe of the low-pressure cylinder 3 after ensuring the steam dryness, and enters the low-pressure cylinder 3 to directly cool the low-pressure cylinder 3, thereby achieving the purpose of protecting the impeller and blades of the low-pressure cylinder 3 and maintaining the normal operation of the steam turbine;

[0055] The steam temperature and superheat at the outlet of the steam jet type desuperheating device 6 are controllable, and steam with different parameters can be matched according to different working conditions to meet various requirements for cooling the low-pressure cylinder 3; at the same time, its flow rate can also be adjusted to better meet the requirements for cooling the low-pressure cylinder 3;

[0056] The method for using the system including the steam jet type cooling device as described above comprises the following steps: gradually closing the medium and low pressure connecting pipe butterfly valve 8 during the cylinder cutting process, and simultaneously opening the power steam pipeline isolation valve 632 and the power steam regulator 631; after the medium and low pressure connecting pipe butterfly valve 8 is completely closed, the medium exhaust steam pressure increases, and in order to ensure that the steam flow rate in the bypass steam pipeline does not exceed the limit, the opening of the power steam regulator 631 is adjusted accordingly, and it is ensured that within this opening range, the steam jet type cooling device 6 effectively mixes the exhaust steam and cooling water from the medium pressure cylinder 2, wherein the cooling water in the cooling water atomizing assembly 62 is sucked into the steam jet type cooling device 6, and rapidly boils and vaporizes in the steam jet type cooling device 6 to mix with the steam and effectively absorb the heat of the steam to form superheated steam at a relatively low temperature, and the exhaust steam is connected to the low pressure cylinder 3 as the low pressure cylinder cooling steam;

[0057] The cooling water is adjusted to the opening of the cooling water regulating valve group 622 according to the exhaust steam temperature of the low-pressure cylinder 3, and the cooling steam temperature is adjusted by controlling the cooling water flow rate.

[0058] The beneficial effects are:

[0059] The steam jet type desuperheating device and system provided by the present invention have the following advantages: it can replace the existing low-pressure cylinder cooling steam system, only a small amount of heating steam is needed to be matched with atomized cooling water, water and steam are mixed and fully expanded in the desuperheater, and the outlet steam is superheated dry steam, without the risk of steam carrying water; in the early stage of steam-water mixing, since the high-temperature steam is ejected through the Rafale nozzle, its speed reaches supersonic speed, and the entrainment capacity of the low-temperature water mist is much greater than that of other mixing methods; in the steam-water mixing process, the shock wave effect is utilized to mix the atomized water and steam at a high speed and fully, and its effect is also much greater than that of other mixing methods; in the latter stage of the steam-water mixing, the expansion mixing is adopted to further enhance the mixing effect; the outlet steam temperature and superheat of the desuperheater are adjustable, and the cooling steam temperature can be reduced as low as possible, thereby effectively reducing the exhaust temperature of the low-pressure cylinder and protecting the safety of the low-pressure cylinder; the system structure is simple and easy to operate, and the optimal atomized water parameters can be obtained by design to reduce the cooling steam temperature of the low-pressure cylinder, improve the steam dryness, and protect the safety of the blades.

[0060] It should be noted that the orientations or positional relationships indicated by the above-mentioned terms "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first", "second", etc. are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. "Multiple" means two or more. "Installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection.

[0061] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and equivalent changes made by using the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A steam jet cooling device, characterized in that: It includes a steam jet type desuperheater (61), a cooling water atomization assembly (62), a power steam assembly (63), and an exhaust outlet steam pipeline isolation valve (64); A steam jet desuperheater (61) is provided with a steam end (611) at one end, a discharge end (613) at the other end, and a suction end (612) near the steam end (611); The steam end (611) is connected to the power steam component (63), the suction end (612) is connected to the cooling water atomization component (62), and the discharge end (613) is connected to the discharge outlet steam pipeline isolation valve (64).

2. The steam jet cooling device according to claim 1, characterized in that: The cooling water atomizing assembly (62) comprises a cooling water atomizing device (621), a cooling water regulating valve group (622), and an atomizing water pipeline isolation valve (623); the cooling water atomizing device (621) is connected to the suction end (612) via a pipeline, one end of the cooling water atomizing device (621) away from the suction end (612) is connected to the cooling water regulating valve group (622) via a pipeline, and one end of the cooling water regulating valve group (622) away from the cooling water atomizing device (621) is connected to the atomizing water pipeline isolation valve (623) via a pipeline.

3. The steam jet type temperature reduction device according to claim 2, characterized in that: The pipeline between the cooling water regulating valve group (622) and the atomizing water pipeline isolation valve (623) is connected to the desalted water pipeline, and a desalted water isolation valve (624) is provided on the desalted water pipeline.

4. The steam jet type temperature reduction device according to claim 1, characterized in that: The motive steam assembly (63) includes a motive steam regulator (631) and a motive steam pipeline isolation valve (632); The motive steam regulator (631) is connected to the steam end (611) through a pipeline, and one end of the motive steam regulator (631) away from the steam end (611) is connected to the motive steam pipeline isolation valve (632) through a pipeline.

5. The steam jet type temperature reduction device according to claim 4, characterized in that: The pipeline between the power steam regulator (631) and the power steam pipeline isolation valve (632) connects the three-extraction steam pipeline and the four-extraction steam pipeline. The three-extraction steam pipeline is provided with a three-extraction steam isolation valve (633), and the four-extraction steam pipeline is provided with a four-extraction steam isolation valve (634).

6. A system comprising the steam injection desuperheater according to claim 1, characterized in that: It comprises a high-pressure cylinder (1), a medium-pressure cylinder (2), a low-pressure cylinder (3), a condenser (4), a condensate pump (5), and a steam jet-type temperature reduction device (6); The steam outlet end of the high-pressure cylinder (1) is connected to the steam inlet end of the medium-pressure cylinder (2), the exhaust pipe on the other side of the medium-pressure cylinder (2) is connected to the low-pressure cylinder (3), the exhaust pipe on the other side of the low-pressure cylinder (3) is connected to the condenser (4), and the condensate pipe on the other side of the condensate pump (5) is connected to the inlet; The pipeline of the power steam component (63) away from the steam end (611) is connected to the exhaust pipe of the medium-pressure cylinder (2), the end of the cooling water atomization component (62) away from the suction end (612) is connected to the condensate pipeline at the outlet of the condensate pump (5), and the end of the exhaust steam pipeline isolation valve (64) away from the discharge end (613) is connected to the steam inlet end of the low-pressure cylinder (3) through a pipeline.

7. The system comprising a steam jet desuperheater according to claim 6, characterized in that: A medium- and low-pressure connecting pipe butterfly valve (8) is provided on the exhaust steam pipeline between the medium-pressure cylinder (2) and the low-pressure cylinder (3).

8. The system comprising a steam jet desuperheater according to claim 7, characterized in that: An external steam supply pipeline is provided on the exhaust pipeline of the medium- and low-pressure connecting pipe butterfly valve (8) away from the low-pressure cylinder (3), and the external steam supply pipeline is provided with a medium-exhaust steam external steam supply isolation valve (7).

9. A method for using a system comprising a steam jet desuperheater as claimed in claim 9, characterized in that: The steps are as follows: during the cylinder cutting process, the medium and low pressure connecting pipe butterfly valves (8) are gradually closed, and the power steam pipeline isolation valve (632) and the power steam regulator (631) are opened at the same time; when the medium and low pressure connecting pipe butterfly valves (8) are completely closed, the medium exhaust steam pressure increases, and in order to ensure that the steam flow rate in the bypass steam pipeline does not exceed the limit, the opening of the power steam regulator (631) is adjusted accordingly, and it is ensured that within this opening range, the steam jet cooling device (6) effectively mixes the exhaust steam and cooling water from the medium pressure cylinder (2), wherein the cooling water in the cooling water atomizing component (62) is sucked into the steam jet cooling device (6), and rapidly boils and vaporizes in the steam jet cooling device (6) to mix with the steam and effectively absorb the heat of the steam to form superheated steam at a relatively low temperature, and the exhaust steam is connected to the low pressure cylinder (3) as the low pressure cylinder cooling steam.

10. The method for using a system comprising a steam jet desuperheater according to claim 9, characterized in that: The cooling water is adjusted to the opening of the cooling water regulating valve group (622) according to the exhaust temperature of the low-pressure cylinder (3), and the cooling steam temperature is adjusted by controlling the cooling water flow rate.

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