Steam system of cylinder and steam turbine, steam turbine coupled molten salt heat storage system

Abstract

The present invention provides a steam system of a cylinder and a steam turbine, and a steam turbine coupled with a molten salt heat storage system. The system does not need to use electric heating or other heating methods to increase the steam temperature of the molten salt heat storage system to reach the boiler steam temperature. According to the temperature of the second steam generated by the molten salt heat storage system, a steam equalization chamber and a steam mixing section are arranged at a position matching the steam energy level of the molten salt system before a certain level in the turbine flow passage. According to the second steam pressure of the molten salt heat storage system or the steam source of the molten salt heat storage system, the second steam enters the high-pressure cylinder and the medium-pressure cylinder of the steam turbine respectively, and after being mixed with the first steam before a certain level structure in the inner cavity of the steam turbine, enters the subsequent levels to work together, thereby achieving the purpose of rapidly increasing the load of the steam turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation, and in particular to a steam system of a cylinder and a steam turbine, and a steam turbine coupled with a molten salt heat storage system. Background Art

[0002] One of the important factors restricting the flexibility of coal-fired power units is that when the units are rapidly increasing their load, the fuel supply cannot meet the requirements of the load increase rate, resulting in the coal-fired boiler being unable to quickly generate enough incremental steam. At present, the molten salt heat storage system is used to store the heat during the low power demand period in molten salt. During the rapid load increase stage, steam is generated through the molten salt heat storage system and enters the steam turbine to increase power.

[0003] However, the steam generated by the molten salt heat storage system can generally reach a maximum temperature of about 500 degrees Celsius, which is lower than the steam temperature generated by the boiler (such as 600 degrees Celsius). If it is directly mixed with superheated steam or reheated steam, the steam inlet temperature of the turbine is reduced, affecting the efficiency of the unit. If the steam from the molten salt heat storage system enters the boiler and is raised to the boiler design temperature, the burden on the boiler is increased, and the total output thermal power of the boiler cannot meet the load increase requirements, reducing the boiler load increase rate, and the boiler structure is also difficult to achieve. If the steam temperature of the molten salt heat storage system is increased by electric heating, since the unit cycle efficiency is generally between 40% and 50% (related to the unit parameters, capacity and relative load rate), only about 40% of the consumed electricity is recovered as electrical energy, and the factory electricity is consumed when the power grid needs electrical load, which is contrary to the purpose of rapid load increase.

[0004] How to improve energy utilization is a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0005] The object of the present invention is to provide a steam system of a cylinder and a steam turbine, and a steam turbine coupled with a molten salt heat storage system with relatively high energy utilization rate.

[0006] To achieve the above purpose, one embodiment of the present application adopts the following technical solution:

[0007] A steam turbine cylinder comprises a cylinder body, wherein the cylinder body has a steam flow channel, a first steam inlet, a second steam inlet and a steam outlet.

[0008] The steam flow channel is provided with a plurality of level structures arranged along the axial direction;

[0009] The first steam inlet is used to introduce a first stream of steam from a boiler, and the first stream of steam flowing in from the first steam inlet flows through all the stage structures to the steam outlet;

[0010] The second steam inlet is used to introduce a second stream of steam from the molten salt heat storage system. The second steam inlet is arranged at a specified position of the cylinder body, and the difference between the energy level of the first stream of steam and the energy level of the second stream of steam at the specified position is within a predetermined range.

[0011] Optionally, the second steam inlet is located in a cylinder side wall section corresponding to an adjacent stage structure.

[0012] Optionally, from outside to inside, the second steam inlet includes a mounting hole section, a steam uniform chamber and a steam mixing section which are connected in sequence, the mounting hole section is used for circumferentially sealing installation with an external delivery pipeline of the second steam, the steam uniform chamber is an annular cavity extending along the circumference of the cylinder body, and the annular cavity is connected to the steam flow channel through the steam mixing section.

[0013] Optionally, the steam mixing section is a circumferentially surrounding annular structure, the steam outlet direction of the inner port of the steam mixing section is non-perpendicular to the main flow direction of the first steam, and the inner port faces the downstream stage structure.

[0014] Optionally, the cylinder body comprises a nested inner cylinder and an outer cylinder, the steam flow channel is located in the inner cylinder, the mounting hole section, the steam uniform cavity and the steam mixing section are arranged in the inner cylinder, the mounting hole section is installed with a steam inlet cannula which is circumferentially sealed therewith, and the outer end of the steam inlet cannula passes through the outer cylinder and can be connected to an external pipeline of the second steam;

[0015] Alternatively, the cylinder body is fixed with a partition sleeve, the mounting hole section, the steam uniform chamber and the steam mixing section are arranged on the partition sleeve, the mounting hole section is installed with a steam inlet plug which is circumferentially sealed therewith, and the outer end of the plug passes through the outer cylinder and can be connected to an external pipeline of the second steam.

[0016] Optionally, the steam inlet insert includes an insert and a flange seat integrally formed with the insert, and the flange seat is fixedly mounted on the outer cylinder via a fixing member.

[0017] Optionally, a circumferential gap is provided between the flange seat and a partial pipe section of the insert pipe, the outer cylinder has a boss, and the flange seat is fixed to the boss via the fixing member.

[0018] Optionally, the cylinder is a single-flow or dual-flow cylinder.

[0019] In a second aspect, the present invention further provides a steam turbine, comprising at least one of the cylinders described above, wherein the cylinder is one or more of an ultra-high pressure cylinder, a high pressure cylinder, a medium pressure cylinder or a low pressure cylinder of the steam turbine.

[0020] In a third aspect, the present invention further provides a steam system of a steam turbine coupled with a molten salt heat storage system, comprising the following components:

[0021] A boiler steam supply system, for providing a first stream of steam, having at least one first stream of steam outlet;

[0022] A molten salt heat storage system, used for providing a second stream of steam, having at least one second stream of steam outlet;

[0023] The steam turbine comprises at least one cylinder, wherein the second steam outlet of the molten salt heat storage system is directly connected to a designated position of the cylinder, and the energy level difference between the first steam at the designated position and the second steam of the molten salt heat storage system introduced therein is within a predetermined range.

[0024] Optionally, the steam turbine includes at least one cylinder as described in any one of the above items, the second steam outlet of the molten salt heat storage system is connected to the second steam inlet of the cylinder, and the first steam outlet of the boiler steam supply system is connected to the first steam inlet of the cylinder.

[0025] Optionally, the boiler steam supply system has a boiler superheater and N boiler reheaters, the molten salt heat storage system includes a molten salt superheater and N molten salt heaters, the number of the cylinders is N+1, namely the first cylinder to the N+1th cylinder, the first steam outlet of the boiler superheater is connected to the first steam inlet of the first cylinder, the steam outlet of the molten salt superheater is connected to the second steam inlet of the first cylinder, and the steam outlet of the first-stage cylinder is connected to the first-stage molten salt heater and the first-stage boiler reheater at the same time;

[0026] The first steam inlet and the second steam inlet of the Nth cylinder are respectively connected to the first steam outlet of the N-1th boiler reheater and the second steam outlet of the N-1th molten salt reheater, and the steam outlet of the Nth cylinder is simultaneously connected to the Nth stage molten salt heater and the Nth stage boiler reheater;

[0027] The first steam inlet and the second steam inlet of the N+1th cylinder are respectively connected to the first steam outlet of the Nth boiler reheater and the second steam outlet of the Nth molten salt reheater, and the steam outlet of the N+1th cylinder is connected to an external pipeline.

[0028] Optionally, the number of the boiler reheaters is two, namely the first boiler reheater and the second boiler reheater; the number of the molten salt heaters is two, namely the first molten salt heater and the second molten salt heater; the number of cylinders in the steam turbine is three, namely the first cylinder, the second cylinder and the third cylinder; wherein the first cylinder can be an ultra-high pressure cylinder or a high pressure cylinder, the second cylinder can be a high pressure cylinder or a medium pressure cylinder, and the third cylinder can be a medium and low pressure cylinder or a low pressure cylinder.

[0029] Alternatively, the number of the boiler reheater is one, the number of the molten salt heater is one, and the number of the cylinders is two; the number of cylinders in the steam turbine is three, namely the first cylinder and the second cylinder; wherein the steam inlet pressure of the first cylinder is higher than the steam inlet pressure of the second cylinder.

[0030] Optionally, a control valve is provided on the pipeline connected to each of the first steam inlets and the pipeline connected to each of the second steam inlets for controlling steam flow parameters in the corresponding pipelines.

[0031] Optionally, the temperature difference between the first stream of steam at the designated position and the second stream of steam introduced therein ranges from 0 degrees to 50 degrees.

[0032] In this way, there is no need to use electric heating or other heating methods to increase the steam temperature of the molten salt heat storage system to the steam temperature from the boiler. According to the temperature of the second steam generated by the molten salt heat storage system, a steam chamber and a steam mixing section are set at a position matching the energy level in front of a certain level of structure inside the steam flow channel of the steam turbine. According to the second steam pressure of the molten salt heat storage system or the steam source of the molten salt heat storage system, they enter the steam turbine respectively, and after being mixed with the first steam before a certain level in the cylinder of the steam turbine, they enter the subsequent levels of structures to work together, thereby achieving the purpose of rapidly increasing the load of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structural principle of a steam system of a steam turbine coupled molten salt heat storage system according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 The enlarged schematic diagram at I in the middle;

[0035] Figure 3 This is a schematic diagram of the structural principle of a steam system of a steam turbine coupled molten salt heat storage system according to another embodiment of the present invention.

[0036] Figures 1 to 3 The one-to-one correspondence between the reference numerals and the component names is as follows:

[0037] High-pressure cylinder 1, medium-pressure cylinder 2, low-pressure cylinder 3, insert pipe 4, outer cylinder 5, elastic sealing sleeve 6, steam equalizing chamber 7, inner cylinder 8, downstream stage of confluence point 9, rotor 10, steam mixing section 11, upstream stage of confluence point 12;

[0038] Boiler steam supply system 200, boiler superheater 201, first steam pipeline 202, first main steam regulating valve 203, first boiler reheater 204, second steam pipeline 205, second main steam regulating valve 206, second boiler reheater 207, third steam pipeline 208, third main steam regulating valve 209, first exhaust steam pipeline 210, second exhaust steam pipeline 211, third exhaust steam pipeline 212, fourth exhaust steam pipeline 213;

[0039] Water supply system 100, boiler water supply pipeline 101, molten salt water supply pipeline 102;

[0040] Molten salt heating system 300, molten salt superheater 301, first molten salt steam pipeline 302, first molten salt steam control valve 303, first molten salt heater 304, second molten salt steam pipeline 305, second molten salt steam control valve 306, second molten salt heater 307, third molten salt steam pipeline 308, third molten salt steam control valve 309. DETAILED DESCRIPTION

[0041] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the objectives, technical solutions and advantages of the present application more clear, the present application is further described in detail below in conjunction with the drawings and specific embodiments.

[0042] In the present application, relational terms such as “first” and “second” are used merely to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0043] Please refer to Figures 1 to 3 , Figure 1 A schematic diagram of the structural principle of a steam system of a steam turbine coupled molten salt heat storage system according to an embodiment of the present invention; Figure 2 for Figure 1 The enlarged schematic diagram at I in the middle; Figure 3 This is a schematic diagram of the structural principle of a steam system of a steam turbine coupled molten salt heat storage system according to another embodiment of the present invention.

[0044] The present invention provides a steam system of a steam turbine coupled with a molten salt heat storage system, comprising a boiler steam supply system, a molten salt heat storage system, a steam turbine and a water supply system 100.

[0045] The water supply system 100 is used to provide water to the boiler steam supply system and the molten salt heat storage system. Figure 1 and Figure 3As shown, the water supply system 100 is connected to the boiler steam supply system and the molten salt heat storage system respectively through the boiler water supply pipeline 101 and the molten salt water supply pipeline 102. Of course, the boiler water supply pipeline 101 and the molten salt water supply pipeline 102 can be further provided with flow control valves to control the liquid flow on the corresponding pipelines according to the system working conditions.

[0046] The boiler steam supply system is mainly used to provide the first steam to the steam turbine. The specific structure of the boiler steam supply system can have various forms to provide the first steam at different pressures. Figure 1 and Figure 3 Two specific structures of boiler steam supply system are given. Figure 3 The boiler steam supply system can provide two first steams with different pressures: high-pressure steam and medium-pressure steam; Figure 1 The boiler steam supply system can provide three first steams with different pressures: high-pressure steam, medium-pressure steam and low-pressure steam; or ultra-high-pressure steam, high-pressure steam or medium-low-pressure steam. In the field of boiler power generation, the pressure ranges of ultra-high pressure, high pressure, medium pressure and low pressure are clearly defined. The specific pressure values ​​given in this article do not prevent those skilled in the art from understanding and implementing the technical solutions described in this article.

[0047] by Figure 1 For example, the boiler steam supply system includes a boiler superheater 201, a first boiler reheater 204 and a second boiler reheater 207, that is, the system is a secondary reheating system, and the working parameters of the first boiler reheater 204 and the second boiler reheater 207 can be adjusted according to the actual working conditions to generate steam that meets the demand. The water in the boiler feed water pipeline 101 can enter the inlet of the boiler superheater 201, and form high-pressure steam or ultra-high-pressure steam with predetermined parameters after passing through the boiler superheater 201. The inlets of the first boiler reheater 204 and the second boiler reheater 207 are respectively connected to the steam pipelines flowing out of the corresponding cylinders of the steam turbine, so as to reheat the corresponding part of the steam.

[0048] That is to say, Figure 1 The middle boiler steam supply system has three first steam outlets.

[0049] The structure of the boiler steam supply system is not limited to the secondary reheat system, but can also be a primary reheat system, such as Figure 3 As shown, of course, it can also be a three-time or more reheat system. For the specific structure of the boiler steam supply system, please refer to the current technology, and this article does not make any specific limitations.

[0050] The molten salt heat storage system in the present invention mainly utilizes the heat stored in the molten salt medium to heat the liquid medium from the water supply system or reheat the exhaust steam from the steam turbine to form a second stream of steam. The molten salt heat storage system has at least one second stream of steam outlet; Figure 1 and Figure 3 As shown, Figure 3 The medium molten salt heat storage system has two second steam outlets, which can provide steam of two different energy levels. Figure 1 The molten salt heat storage system has three second steam outlets, which can provide three steams with different energy levels. The molten salt heat storage system can specifically include a molten salt superheater 301 and at least one molten salt heater. The first molten salt heater 304, the second molten salt heater 307 and other heaters are used to reheat the steam of different energy levels discharged from the steam turbine using the heat stored in the molten salt system to further improve the working efficiency of the steam turbine. Among them, the molten salt feed water pipeline 102 can be connected to the molten salt superheater 301 to form high-temperature steam.

[0051] The main function of the steam turbine is to convert part of the heat energy of the first steam and the second steam into the kinetic energy of the rotor, and then convert the rotor kinetic energy into electrical energy through the generator. The steam turbine includes one or more of an ultra-high pressure cylinder, a high pressure cylinder, an intermediate pressure cylinder and a low pressure cylinder. A coaxial rotor is arranged inside the cylinder body of each cylinder, and a stage structure is arranged on the rotor. When the steam flows through the stage structure, it drives the rotor to rotate. The stage structure includes moving blades and nozzles. The moving blades are fixedly connected to the rotor, and the nozzle is fixed to the cylinder body. The structure of the moving blades and nozzles is not described in detail in this article.

[0052] The molten salt heater and the boiler reheater in the present invention can both reheat part of the steam flowing out of a cylinder of the steam turbine, and the heated steam can be passed into the cylinder of the next stage to work again, so as to improve the steam work efficiency.

[0053] The present invention directly passes the second stream of steam generated by the molten salt heat storage system into the designated position of the cylinder, and the difference between the energy level of the first stream of steam at the designated position and the energy level of the second stream of steam in the molten salt heat storage system is within a predetermined range. The energy level of the steam can be comprehensively judged by temperature and pressure. For the molten salt steam system, the temperature of the second stream of steam depends on the molten salt temperature, so the temperature of the generated steam is basically the same, and the energy level depends on the source of the medium. For example, the steam at the outlet of the molten salt superheater comes from the boiler feed water and has a level similar to the inlet pressure of the ultra-high pressure or high pressure cylinder. The molten salt superheated steam should enter the second steam inlet of the first cylinder, and the steam at the outlet of the molten salt heater should enter the cylinder corresponding to the boiler reheat steam.

[0054] Theoretically, the temperature and pressure of the two steams are roughly the same or similar, and the energy levels of the two steams can be considered to be roughly the same or similar. In a specific example, the temperature difference between the second steam and the first steam inside the cylinder at that location is in the range of 0 to 50 degrees. For example, the temperature difference between the first steam at a specified location and the temperature of the molten salt steam introduced does not exceed 10°C, and the temperature change at that point does not exceed 28°C during the load process from 30% to 80%.

[0055] Compared with the coupling of the steam of the molten salt heat storage system and the boiler steam in the background technology, in the present invention, a flow position close to the steam temperature of the molten salt heat storage system is selected in the cylinder of the steam turbine, and the second steam of the molten salt heat storage system is introduced from this position. In this way, there is no need to perform additional heating on the steam generated by the molten salt heat storage system, thereby improving the energy utilization rate of the entire system.

[0056] In order to achieve the above technical effects, the present invention makes corresponding improvements to the cylinder structure of the steam turbine.

[0057] The cylinder of the steam turbine provided by the present invention can be used as an ultra-high pressure cylinder, a high pressure cylinder, a medium pressure cylinder or a low pressure cylinder as long as the material and structure of the cylinder are reasonably set. The cylinder includes a cylinder body, and the cylinder body has a steam flow channel, a partition sleeve, a first steam inlet, a second steam inlet and a steam outlet. The steam flow channel or the partition sleeve can accommodate several stage structures arranged along the axial direction. The first steam inlet is used to introduce the first steam, and the first steam inlet is connected to the steam outlet of the boiler steam supply system. The first steam flowing in from the first steam inlet flows to the steam outlet through all the stage structures; the second steam inlet is used to introduce the second steam, and the second steam inlet is set at a specified position of the cylinder body. The energy level of the first steam at the specified position and the energy level of the second steam introduced to the position are within a predetermined range.

[0058] In the above example, the first steam inlet and the steam outlet can be arranged near the two ends of the cylinder respectively, and the second steam inlet is arranged on the cylinder side wall between the first steam inlet and the steam outlet. In a specific example, the second steam inlet is located in the cylinder side wall section corresponding to the adjacent level structure. This setting structure is relatively simple.

[0059] In a specific example, from outside to inside, the second steam inlet includes a mounting hole section, a steam equalizing chamber 7 and a steam mixing section 11 which are connected in sequence. The mounting hole section is used for circumferential sealing installation with the conveying pipeline of the second steam. Specifically, the mounting hole section can be provided with an elastic sealing sleeve 6, and the conveying pipeline and the mounting hole section are circumferentially sealed and installed through the elastic sealing sleeve 6. The steam equalizing chamber 7 is an annular chamber extending along the circumference of the cylinder body, and the annular chamber is connected to the steam flow channel through the steam mixing section 11. In this way, the second steam can enter the annular chamber first, and the annular chamber can play a role of pressure buffering, reducing the disturbance of the second steam entering the cylinder body to the turbine rotor, which is conducive to the stable operation of the turbine.

[0060] Since the molten salt heat storage steam is evenly distributed in the steam uniforming chamber 7 before entering the turbine flow, after mixing with the mainstream first steam from the boiler in the steam mixing section 11, it will not have a significant impact on the steam distribution in the turbine flow, will not cause flow concentration, and will not cause disturbances to the turbine rotor.

[0061] The steam mixing section 11 can also be a circumferentially surrounding annular structure, so that the second steam flows out from the entire circumference of the inner wall of the cylinder, which is conducive to the uniform mixing of the second steam and the first steam. In addition, the flow area of ​​the steam mixing section is relatively large, and the flow velocity of the second steam is relatively low, which has a relatively small impact on the flow of the first steam inside the cylinder.

[0062] In addition to being inserted into the inner cylinder, the end of the insert pipe 4 may also be inserted into a partition sleeve. The above-mentioned mounting hole section, the steam equalizing chamber 7 and the steam mixing section 11 are arranged on the partition sleeve. An elastic sealing sleeve 6 is arranged on the partition sleeve to achieve communication and sealing between the steam inlet insert pipe 4 and the partition sleeve.

[0063] In a specific example, the steam outlet direction of the inner port of the steam mixing section 11 is not perpendicular to the main flow direction of the first steam, and the inner port faces the downstream structure, which is conducive to the second steam flowing downstream. Ultra-high pressure cylinder, high pressure cylinder or medium pressure cylinder. The cylinder can be a single cylinder, and the cylinder body is a single-layer structure. The cylinder can also be a double-layer cylinder body, which is particularly suitable for cylinders with higher pressures. The cylinder body includes a nested inner cylinder 8 and an outer cylinder 5, and the mounting hole section, the steam chamber 7 and the steam mixing section 11 are arranged on the side wall of the inner cylinder 8. The mounting hole section is equipped with a cannula 4 that is circumferentially sealed therewith, and the outer end of the cannula 4 passes through the outer cylinder 5 and can be connected to the external pipeline of the second steam.

[0064] The double-layer cylinder body has relatively high strength and can be used as a high-pressure cylinder and an ultra-high-pressure cylinder.

[0065] In a specific example, the outer end of the steam inlet pipe 4 is fixedly connected or integrally formed with a flange seat 4b. Figure 2 4a and the flange seat 4b are integrally formed. Of course, the insert pipe 4a and the flange seat 4b can also be welded. The flange seat 4b is fixedly mounted on the outer cylinder 5 by a fixing member 13. The fixing member 13 can be a screw or bolt connection. The insert pipe structure can absorb a small amount of deformation and reduce stress.

[0066] In a specific example, the steam inlet pipe is a skirt-type structure, and the end of the pipe flange seat 4b away from the outer cylinder 5 is fixedly connected to or integrally formed with the pipe 4a. There is a circumferential gap between the flange seat 4b and a partial pipe section of the pipe 4a, and there is an annular space between the end of the steam inlet pipe close to the outer cylinder 5 and the fixed flange seat, which can withstand a small deformation of the steam inlet pipe. As shown in the figure, the flange seat 4b is fixedly connected to the outer cylinder 5 by screws 13. In order to facilitate connection and improve the use strength of the outer cylinder 5, a boss can be set on the outer wall of the outer cylinder 5, and the fixing part fixes the pipe flange to the boss.

[0067] The cylinder body of the cylinder usually includes two detachable structures, that is, the cylinder body can include an upper cylinder body and a lower cylinder body, and the second steam inlet can be set in the upper cylinder body, the lower cylinder body or an opening at about 45 degrees perpendicular to the horizontal center plane. The so-called center plane refers to the joint surface of the upper cylinder body and the lower cylinder body.

[0068] The cylinder can be a unidirectional flow cylinder or a dual-flow cylinder. The dual-flow cylinder includes a symmetrical first cylinder body and a second cylinder body. The first cylinder body and the second cylinder body are both provided with a step structure. The first steam inlet is provided between the first cylinder body and the second cylinder body. Steam outlets are provided at two ends of the first cylinder body and the second cylinder body that are relatively far away from each other. The first cylinder body and the second cylinder body are both provided with a second steam inlet. Please refer to Figure 1 In the figure, the structure of the medium-pressure cylinder 3.

[0069] Specific implementations of two steam systems are given below.

[0070] In one example, Figure 1 For example, the steam turbine is provided with three cylinders, which are respectively: high-pressure cylinder 1, medium-pressure cylinder 2 and low-pressure cylinder 3 along the direction of fluid flow. Figure 1 A part of the boiler feed water pipeline 101 provided by the intermediate feed water system 100 enters the boiler superheater 201, which can be a high-pressure superheater or an ultra-high-pressure superheater (the ultra-high-pressure superheater is mainly used for secondary intermediate reheat boilers). The high-temperature superheated steam generated by the boiler superheater 201 enters the high-pressure cylinder 1 of the steam turbine after the flow rate is adjusted by the first steam pipeline 202 and the first main steam regulating valve 203; a part of the high-pressure steam after the high-pressure cylinder 1 has done work enters the first boiler reheater 204 of the boiler through the first exhaust steam pipeline 210 for reheating, and the steam after the first reheating passes through the second steam pipeline 205 and is adjusted by the second main steam regulating valve 206 to enter the intermediate pressure cylinder 2 of the steam turbine; a part of the steam after the intermediate pressure cylinder 2 has done work enters the second boiler reheater 207 of the boiler through the third exhaust steam pipeline 212 for reheating, and the steam after the second reheating passes through the third steam pipeline 208 and is adjusted by the third main steam regulating valve 209 to enter the low-pressure cylinder 3 of the steam turbine to do work.

[0071] Another part of boiler feed water provided by the feed water system 100 enters the molten salt superheater 301 (for the secondary intermediate reheat steam turbine, the molten salt superheater is an ultra-high pressure molten salt heat storage) through the molten salt feed water pipeline 102. The generated ultra-high pressure molten salt heat storage steam passes through the first molten salt steam pipeline 302 and is adjusted by the first molten salt steam control valve 303 before entering the high pressure cylinder 1 of the steam turbine.

[0072] The steam of the molten salt heat storage system is introduced into the steam uniformity chamber 7 arranged on the high-pressure cylinder through the intubation pipe 4 for rapid and uniform distribution, and then enters the steam mixing section 11, and is uniformly mixed with the first mainstream steam from the boiler at the upstream stage 12 of the molten salt steam inlet point, and then flows into the downstream stage 9 of the turbine inlet point.

[0073] Another part of the steam discharged from the high-pressure cylinder 1 enters the first molten salt heater 304 through the second exhaust steam pipeline 211, and the generated high-pressure molten salt heat storage steam (second steam) passes through the second steam pipeline 305, and is adjusted by the first molten salt steam control valve 306 and enters the skirt-type steam inlet 4 of the intermediate-pressure cylinder 2 of the steam turbine. This second steam is mixed with the steam from the first boiler reheater 204 and discharged from the intermediate-pressure cylinder 2. Part of the discharged steam enters the second boiler reheater 207 of the boiler, and the other part enters the second molten salt heater 307 through the fourth exhaust steam pipeline 213. The heated steam passes through the third steam pipeline 308, and is adjusted by the third molten salt steam control valve 309 and enters the duct 4 of the low-pressure cylinder 3 of the steam turbine. This steam is mixed with the steam from the second boiler reheater 207 and discharged from the intermediate-pressure cylinder 3.

[0074] In this embodiment, the high-pressure cylinder 1, the medium-pressure cylinder 2 and the low-pressure cylinder 3 of the steam turbine all adopt the above-mentioned cylinder structure. In addition to the conventional first steam from the boiler steam supply system 200 expanding and doing work in the various levels of the steam turbine structure, the high-temperature steam generated by the molten salt heat storage system is also received at a designated position where the steam energy level of the steam turbine matches the steam energy level of the molten salt heat storage system. The molten salt heat storage steam with different parameters enters the ultra-high pressure cylinder or high pressure cylinder, medium pressure cylinder or low pressure cylinder pressure level through their respective pipeline systems and adjustment valves. The second steam of the molten salt heat storage system is mixed with the mainstream first steam generated by the boiler and works together in the downstream stage 9 of the steam turbine thereafter, so as to achieve the purpose of rapidly increasing the load of the steam turbine and improving the operational flexibility of the coal-fired power unit.

[0075] In this way, there is no need to use electric heating or other heating methods to increase the steam temperature of the molten salt heat storage system. According to the temperature of the second steam generated by the molten salt heat storage system, a steam equalization chamber and a steam mixing section are set at a position matching the energy level before a certain stage inside the turbine stage group. According to the second steam pressure of the molten salt heat storage system or the steam source of the molten salt heat storage system, they enter the ultra-high pressure cylinder 1 (for secondary intermediate reheat steam turbine), high pressure cylinder 2 and medium pressure cylinder 3 respectively, and after mixing with the steam before a certain stage of the steam turbine stage group, they enter the subsequent stages to work together, thereby achieving the purpose of quickly increasing the turbine load.

[0076] The steam of the molten salt heat storage system is not from the valves of each cylinder of the steam turbine (such as Figure 1 The steam does not enter the cylinder body cavity through the first steam inlet 203 / 206 / 209 (marked in the figure), but flows into the corresponding stage in the middle of the turbine from the second steam inlet 303 / 306 / 309 of the corresponding cylinder.

[0077] Please refer to Figure 3In another specific embodiment, the number of reheaters in the boiler steam supply system 200 can be one, that is, the boiler steam supply system includes a boiler superheater 201 and a primary reheater 204, the molten salt heat storage system includes a molten salt superheater 301 and a first molten salt heater 304, and the steam turbine includes two cylinders: a high-pressure cylinder 1 and an intermediate-pressure cylinder 2. The connection method of each component can refer to the above description. Figure 3 The enlarged view of the I position in the middle cylinder and Figure 1 The structure is the same as in I.

[0078] Of course, the number of reheaters in the boiler, the number of heaters in the molten salt heat storage system, and the number of cylinders in the steam turbine may not be limited to the description in this article. That is, the boiler steam supply system has a boiler superheater and N boiler reheaters, the molten salt heat storage system includes a molten salt superheater and N molten salt heaters, the number of cylinders is N+1, which are the first cylinder to the N+1 cylinder, respectively, the first steam outlet of the boiler superheater is connected to the first steam inlet of the first cylinder, the steam outlet of the molten salt superheater is connected to the second steam inlet of the first cylinder, and the steam outlet of the first cylinder is connected to the first-stage molten salt heater and the first-stage boiler reheater at the same time.

[0079] The first steam inlet and the second steam inlet of the Nth cylinder are connected to the first steam outlet of the N-1th boiler reheater and the second steam outlet of the N-1th molten salt reheater respectively, and the steam outlet of the Nth stage cylinder is connected to the Nth stage molten salt heater and the Nth stage boiler reheater at the same time.

[0080] The first steam inlet and the second steam inlet of the N+1th cylinder are connected to the first steam outlet of the Nth boiler reheater and the second steam outlet of the Nth molten salt reheater respectively, and the steam outlet of the N+1th cylinder is connected to the external pipeline.

[0081] The pipelines communicating with each of the first steam inlets and the pipelines communicating with each of the second steam inlets are both provided with control valves to control steam flow parameters such as pressure and steam flow rate in the corresponding pipelines.

[0082] The above is a detailed introduction to a steam system of a cylinder and a steam turbine, and a steam turbine coupled molten salt heat storage system provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A steam system of a steam turbine coupled with a molten salt heat storage system, characterized in that: Includes the following components: A boiler steam supply system, for providing a first stream of steam, having at least one first stream of steam outlet; A molten salt heat storage system, used for providing a second stream of steam, having at least one second stream of steam outlet; A steam turbine, comprising at least one cylinder, wherein the cylinder comprises a cylinder body, wherein the cylinder body has a steam flow channel, a first steam inlet, a second steam inlet and a steam outlet, wherein the steam flow channel is provided with a plurality of stage structures arranged in an axial direction; The first steam outlet of the boiler steam supply system is connected to the first steam inlet of the cylinder, and the first steam flowing in from the first steam inlet flows to the steam outlet through all the stage structures; the second steam outlet of the molten salt heat storage system is connected to the second steam inlet of the cylinder, and the second steam inlet is arranged at a specified position of the cylinder body, and the difference between the energy level of the first steam and the energy level of the second steam at the specified position is within a predetermined range.

2. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 1, characterized in that: The boiler steam supply system has a boiler superheater and N boiler reheaters, the molten salt heat storage system includes a molten salt superheater and N molten salt heaters, the number of the cylinders is N+1, namely the first cylinder to the N+1th cylinder, the first steam outlet of the boiler superheater is connected to the first steam inlet of the first cylinder, the steam outlet of the molten salt superheater is connected to the second steam inlet of the first cylinder, and the steam outlet of the first cylinder is connected to the first-stage molten salt heater and the first-stage boiler reheater at the same time; The first steam inlet and the second steam inlet of the Nth cylinder are respectively connected to the first steam outlet of the N-1th boiler reheater and the second steam outlet of the N-1th molten salt reheater, and the steam outlet of the Nth cylinder is simultaneously connected to the Nth molten salt heater and the Nth boiler reheater; The first steam inlet and the second steam inlet of the N+1th cylinder are respectively connected to the first steam outlet of the Nth boiler reheater and the second steam outlet of the Nth molten salt reheater, and the steam outlet of the N+1th cylinder is connected to an external pipeline.

3. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 2, characterized in that: The number of the boiler reheaters is two, namely the first boiler reheater and the second boiler reheater; the number of the molten salt heaters is two, namely the first molten salt heater and the second molten salt heater; the number of the cylinders in the steam turbine is three, namely the first cylinder, the second cylinder and the third cylinder.

4. The steam system of the steam turbine coupled molten salt heat storage system as claimed in claim 2, wherein the number of the boiler reheater is one, the number of the molten salt heater is one, and the number of the cylinders is two; the number of cylinders in the steam turbine is three, namely the first cylinder and the second cylinder.

5. The steam system of the steam turbine coupled molten salt thermal storage system according to any one of claims 1 to 4, characterized in that: The pipelines communicating with each of the first steam inlets and the pipelines communicating with each of the second steam inlets are both provided with control valves for controlling steam flow parameters in the corresponding pipelines.

6. The steam system of the steam turbine coupled molten salt thermal storage system according to any one of claims 1 to 4, characterized in that: The difference between the temperature of the second steam and the temperature of the first steam at the designated position ranges from 0 degrees to 50 degrees.

7. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 1, characterized in that: The second steam inlet is located in a cylinder side wall section corresponding to an adjacent stage structure.

8. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 7, characterized in that: From the outside to the inside, the second steam inlet includes a mounting hole section, a steam uniform chamber and a steam mixing section which are connected in sequence. The mounting hole section is used for circumferentially sealing installation with the external conveying pipeline of the second steam. The steam uniform chamber is an annular cavity extending along the circumference of the cylinder body. The annular cavity is connected to the steam flow channel through the steam mixing section.

9. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 8, characterized in that: The steam mixing section is a circumferentially surrounding annular structure, the steam outlet direction of the inner port of the steam mixing section is not perpendicular to the main flow direction of the first steam, and the inner port faces the downstream stage structure.

10. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 8, characterized in that: The cylinder body comprises an inner cylinder and an outer cylinder which are nested, the steam flow channel is located in the inner cylinder, the mounting hole section, the steam uniform cavity and the steam mixing section are arranged in the inner cylinder, the mounting hole section is provided with a steam inlet insert which is circumferentially sealed therewith, and the outer end of the steam inlet insert passes through the outer cylinder and can be connected to an external pipeline of the second steam; Alternatively, the cylinder body is fixed with a partition sleeve, the mounting hole section, the steam uniform chamber and the steam mixing section are arranged on the partition sleeve, the mounting hole section is installed with a steam inlet pipe which is circumferentially sealed therewith, and the outer end of the steam inlet pipe passes through the outer cylinder and can be connected to an external pipeline of the second steam.

11. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 10, characterized in that: The steam inlet insert comprises an insert and a flange seat integrally formed with the insert, and the flange seat is fixedly mounted on the outer cylinder via a fixing member.

12. The steam system of the steam turbine coupled molten salt thermal storage system according to claim 11, characterized in that: There is a circumferential gap between the flange seat and a partial pipe section of the insert pipe, the outer cylinder has a boss, and the flange seat is fixed to the boss through the fixing piece.

13. The steam system of the steam turbine coupled molten salt thermal storage system according to any one of claims 1 to 4 and 7 to 12, characterized in that: The cylinder is a single-flow cylinder or the cylinder is a dual-flow cylinder.

14. The steam system of the steam turbine coupled molten salt thermal storage system according to any one of claims 1 to 4 and 7 to 12, characterized in that: The cylinder is one or more of the ultra-high pressure cylinder, high pressure cylinder, medium pressure cylinder or low pressure cylinder of the steam turbine.

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