Peak shaving system of coal-fired unit

Abstract

The invention discloses a coal-fired unit peak load regulation system which comprises a pulverized coal storage bin system, a coal-fired unit peak load regulation system and a coal-fired unit peak load regulation system. The coal-fired unit is provided with a pulverized coal inlet, a gas supply pipe, a water supply pipe and a flue gas discharge pipe, and the pulverized coal inlet is communicated with the pulverized coal storage bin; the energy storage and supply system comprises a fused salt circulation pipeline, a water circulation pipeline and a plurality of heat exchangers, a fused salt tank and a heat storage device are connected to the fused salt circulation pipeline in series, the heat storage device is connected with a flue gas discharge pipe and used for enabling flue gas discharged through the flue gas discharge pipe to heat fused salt in the heat storage device, and each heat exchanger comprises a fused salt flow channel and a water flow channel which exchange heat with each other. The fused salt flow channels of the heat exchangers are sequentially connected to the fused salt circulation pipeline in series, the water flow channels of the heat exchangers are sequentially connected to the water circulation pipeline in series, and the water circulation pipeline is configured to exchange heat with the gas supply pipe and the water supply pipe so as to heat gas in the gas supply pipe and liquid in the water supply pipe. According to the peak regulation system of the coal-fired unit, the power generation power of the coal-fired unit can be rapidly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired power generation, and in particular to a peak shaving system for coal-fired units. Background Art

[0002] With the large-scale access of renewable energy sources such as wind energy and solar energy, the power grid faces higher flexibility requirements to adapt to the challenges brought by the intermittency and uncertainty of these energy sources. As an important part of the traditional power system, the rapid load-changing ability of coal-fired units is crucial for the safe and stable operation of the power grid.

[0003] Peak shaving of coal-fired units refers to adjusting the power generation of coal-fired units to adapt to the changes in the grid load, so as to ensure the stable operation of the power system. Specifically, peak shaving means increasing the power generation when the grid load is at a peak and reducing the power generation when the grid load is at a low valley to meet the fluctuations in power demand.

[0004] In the prior art, the thermal system of coal-fired units, especially the coal-fired unit part, has large thermal inertia and delay due to the complex processes of coal powder preparation, transportation, combustion and working medium heat absorption, making it unable to adjust the energy supply in time under rapid load change, thus restricting the rapid increase of the power generation of coal-fired units. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention provides a peak shaving system for coal-fired units. Through the collaborative work of the coal powder storage bin system and the energy storage and supply system, the peak shaving system for coal-fired units can rapidly increase the power generation of coal-fired units in a short time to adapt to the changes in the grid load, thereby ensuring the stability of the power system.

[0006] The peak shaving system for coal-fired units according to the present invention includes: a coal powder storage bin system including a coal powder storage bin for storing coal powder; a coal-fired unit having a coal powder inlet, a gas supply pipe, a water supply pipe and a flue gas discharge pipe, wherein the coal powder inlet is communicated with the coal powder storage bin; an energy storage and supply system including: a molten salt circulation pipeline, a water circulation pipeline and a plurality of heat exchangers. A molten salt tank and a heat storage device are connected in series on the molten salt circulation pipeline, and the heat storage device is connected to the flue gas discharge pipe for heating the molten salt in the heat storage device with the flue gas discharged through the flue gas discharge pipe. Each heat exchanger includes a molten salt flow channel and a water flow channel for heat exchange with each other. The molten salt flow channels of the plurality of heat exchangers are sequentially connected in series on the molten salt circulation pipeline, and the water flow channels of the plurality of heat exchangers are sequentially connected in series on the water circulation pipeline. The water circulation pipeline is configured to perform heat exchange with the gas supply pipe and the water supply pipe to heat the gas in the gas supply pipe and the liquid in the water supply pipe.

[0007] According to the peak shaving system of a coal-fired unit of the present invention, by providing a pulverized coal storage bin system, a coal-fired unit, and an energy storage and supply system in the peak shaving system of the coal-fired unit, the pulverized coal storage bin system includes a pulverized coal storage bin for storing pulverized coal, the coal-fired unit has a pulverized coal inlet, a gas supply pipe, a water supply pipe, and a flue gas discharge pipe, the pulverized coal inlet is communicated with the pulverized coal storage bin, the energy storage and supply system includes a molten salt circulation pipeline, a water circulation pipeline, and a plurality of heat exchangers, a molten salt tank and a heat accumulator are connected in series on the molten salt circulation pipeline, the heat accumulator is connected to the flue gas discharge pipe and is used for heating the molten salt in the heat accumulator with the flue gas discharged through the flue gas discharge pipe, the heat exchanger includes a molten salt flow channel and a water flow channel for heat exchange with each other, the molten salt flow channels of the plurality of heat exchangers are sequentially connected in series on the molten salt circulation pipeline, the water flow channels of the plurality of heat exchangers are sequentially connected in series on the water circulation pipeline, and the water circulation pipeline is configured to perform heat exchange with the gas supply pipe and the water supply pipe to heat the gas in the gas supply pipe and the liquid in the water supply pipe, and can rapidly increase the power generation power of the coal-fired unit in a short time to adapt to the change of the grid load, thereby ensuring the stability of the power system.

[0008] In some embodiments, the plurality of heat exchangers include a superheater, an evaporator, and a preheater. On the molten salt circulation pipeline, the superheater, the evaporator, and the preheater are sequentially connected in series along the flowing direction of the molten salt in the molten salt circulation pipeline. On the water circulation pipeline, the preheater, the evaporator, and the superheater are sequentially connected in series along the flowing direction of the water in the water circulation pipeline.

[0009] In some embodiments, the molten salt tank includes a high-temperature molten salt tank and a low-temperature molten salt tank. The inlet of the high-temperature molten salt tank is connected to the molten salt outlet of the heat accumulator, the outlet of the low-temperature molten salt tank is connected to the molten salt inlet of the heat accumulator, and the plurality of heat exchangers are sequentially connected in series between the outlet of the high-temperature molten salt tank and the inlet of the low-temperature molten salt tank.

[0010] In some embodiments, a high-temperature molten salt pump and a low-temperature molten salt pump are further connected in series on the molten salt circulation pipeline. The high-temperature molten salt pump is connected between the outlet of the high-temperature molten salt tank and the heat exchanger, and the low-temperature molten salt pump is connected between the outlet of the low-temperature molten salt tank and the heat accumulator.

[0011] In some embodiments, the energy storage and supply system further includes: a heat exchange box, in which a water channel and a gas channel for heat exchange with each other are provided. The water channel is connected in series on the water circulation pipeline, and the gas channel is connected in series on the gas supply pipe; a heat exchange branch pipe, both ends of which are connected to the water circulation pipeline and are arranged between the heat exchange box and the superheater, and a part of the heat exchange branch pipe is wound around the water supply pipe to perform heat exchange with the water supply pipe.

[0012] In some embodiments, the energy storage and supply system further includes: a first control valve, connected in series in the water circulation pipeline and located between the superheater and the heat exchange branch pipe; a second control valve, connected in series in the water circulation pipeline and located between the heat exchange box and the heat exchange branch pipe; a third control valve, connected in series in the heat exchange branch pipe.

[0013] In some embodiments, the energy storage and supply system further includes: a make-up water pipe and a make-up water pump, the make-up water pump is connected in series on the make-up water pipe, and the outlet end of the make-up water pipe is connected to the preheater.

[0014] In some embodiments, the pulverized coal storage bin system further includes: a screw conveyor, a crusher, a dust filtering box and a suction fan, the outlet of the screw conveyor is connected to the inlet of the crusher, a screening plate is provided in the dust filtering box, the inlet of the dust filtering box is connected to the outlet of the crusher, the pulverized coal outlet of the dust filtering box is connected to the pulverized coal storage bin, and the gas outlet of the dust filtering box is connected to the inlet of the suction fan.

[0015] In some embodiments, the pulverized coal storage bin is provided with a level detection device for detecting the height of the pulverized coal in the pulverized coal storage bin.

[0016] In some embodiments, the level detection device includes: a high-level alarm and a low-level alarm, the high-level alarm is arranged at the top of the bin of the pulverized coal storage bin, and the low-level alarm is arranged at the bottom of the bin.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0018] Figure 1 is a schematic diagram of a peak shaving system for a coal-fired power unit according to an embodiment of the present invention.

[0019] Reference Signs:

[0020] 100, peak shaving system for a coal-fired power unit;

[0021] 10, pulverized coal storage bin system; 11, pulverized coal storage bin; 111, level detection device; 1111, high-level alarm; 1112, low-level alarm; 12, screw conveyor; 13, crusher; 14, dust filtering box; 15, suction fan; 16, conveyor belt; 17, pipeline;

[0022] 20, coal-fired power unit; 21, gas supply pipe; 22, water supply pipe; 221, water supply valve; 23, flue gas discharge pipe; 24, blower;

[0023] 30. Energy storage and supply system; 31. Molten salt circulation pipeline; 311. Molten salt tank; 3111. High-temperature molten salt tank; 3112. Low-temperature molten salt tank; 312. Heat storage device; 3121. Flue gas pipe; 313. Molten salt output pipe; 314. Molten salt input pipe; 315. High-temperature molten salt pump; 316. Low-temperature molten salt pump; 32. Water circulation pipeline; 321. Feed water bypass pipe; 3211. Feed water bypass valve; 322. First control valve; 323. Second control valve; 33. Heat exchanger; 331. Superheater; 332. Evaporator; 333. Preheater; 34. Heat exchange box; 35. Heat exchange branch pipe; 351. Third control valve; 36. Make-up water pipe; 361. Make-up water pump. Detailed implementation manners

[0024] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0025] Below, refer to Figure 1 Describe the peak shaving system 100 of a coal-fired power unit according to an embodiment of the present invention.

[0026] As Figure 1 shown, the peak shaving system 100 of a coal-fired power unit according to an embodiment of the present invention includes: a pulverized coal storage bin system 10, a coal-fired power unit 20, and an energy storage and supply system 30.

[0027] The pulverized coal storage bin system 10 includes a pulverized coal storage bin 11 for storing pulverized coal; the coal-fired power unit 20 has a pulverized coal inlet, a gas supply pipe 21, a water supply pipe 22, and a flue gas discharge pipe 23, and the pulverized coal inlet is communicated with the pulverized coal storage bin 11; the energy storage and supply system 30 includes: a molten salt circulation pipeline 31, a water circulation pipeline 32, and a plurality of heat exchangers 33. A molten salt tank 311 and a heat storage device 312 are connected in series on the molten salt circulation pipeline 31. The heat storage device 312 is connected to the flue gas discharge pipe 23 and is used to heat the molten salt in the heat storage device 312 with the flue gas discharged through the flue gas discharge pipe 23. The heat exchangers 33 include a molten salt flow channel and a water flow channel for heat exchange with each other. The molten salt flow channels of the plurality of heat exchangers 33 are connected in series to the molten salt circulation pipeline 31 in sequence, and the water flow channels of the plurality of heat exchangers 33 are connected in series to the water circulation pipeline 32 in sequence. The water circulation pipeline 32 is configured to perform heat exchange with the gas supply pipe 21 and the water supply pipe 22 to heat the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22.

[0028] It should be noted that in some specific examples, such as Figure 1As shown, the coal-fired unit 20 includes a coal-fired furnace and a steam turbine. The heat generated by the combustion of pulverized coal in the coal-fired furnace can heat the liquid and gas entering the coal-fired furnace, turning them into high-temperature and high-pressure steam. The high-temperature and high-pressure steam can enter the steam turbine to drive the turbine to rotate, and then drive the generator to rotate for power generation. The electric energy generated by the generator can be stepped up by a transformer and finally transmitted to the power grid for use.

[0029] In some specific examples, such as Figure 1 As shown, a pulverized coal storage bin 11 is provided in the pulverized coal storage bin system 10, and the pulverized coal storage bin 11 stores pulverized coal that has been prepared in advance and meets the requirements. When it is necessary to quickly increase the power generation capacity of the coal-fired unit 20, during the ramp-up process of the coal-fired unit 20, the original coal-fired furnace coal pulverizing system cannot meet the demand of the coal-fired furnace's load change rate due to the slow grinding start-up process. At this time, the pulverized coal in the pulverized coal storage bin 11 is immediately supplied to the coal-fired furnace of the coal-fired unit 20 through the pulverized coal inlet, which can quickly increase the load of the coal-fired furnace, thereby quickly increasing the steam production rate of the coal-fired furnace, and further quickly increasing the power generation capacity of the coal-fired unit 20.

[0030] In some specific examples, such as Figure 1 As shown, one end of the water supply pipe 22 is connected to the water inlet of the coal-fired unit 20, and the liquid in the water supply pipe 22 can enter the coal-fired unit 20 through the water inlet of the coal-fired unit 20 and exchange heat in the coal-fired unit 20 to form high-temperature and high-pressure steam. Further, a water supply valve 221 is connected in series on the water supply pipe 22. By controlling the opening degree of the water supply valve 221, the amount of liquid supplied to the coal-fired unit 20 can be accurately controlled to match the actual operation requirements.

[0031] In some specific examples, such as Figure 1 As shown, a blower 24 is also provided in the coal-fired unit 20. One end of the air supply pipe 21 is connected to the output end of the blower 24, and the other end of the air supply pipe 21 is connected to the air inlet of the coal-fired unit 20. The blower 24 can transport the gas into the coal-fired unit 20 through the air supply pipe 21 and the air inlet of the coal-fired unit 20, and the gas exchanges heat in the coal-fired unit 20 to form high-temperature and high-pressure steam. Further, by controlling the amount of air blown by the blower 24, the amount of gas supplied to the coal-fired unit 20 can be accurately controlled to match the actual operation requirements.

[0032] In some specific examples, such as Figure 1As shown in the figure, molten salt is stored in the molten salt tank 311. One end of the flue gas discharge pipe 23 is connected to the output end of the coal-fired unit 20, and the other end of the flue gas discharge pipe 23 is connected to the input end of the heat storage device 312. Further, a smoke exhaust pipe 3121 is provided at the bottom of the heat storage device 312. The flue gas generated when the coal-fired unit 20 burns pulverized coal is discharged into the heat storage device 312 through the flue gas discharge pipe 23 to exchange heat with the molten salt, heating the molten salt to a molten state. After that, the flue gas can be discharged into the flue gas treatment system through the smoke exhaust pipe 3121. The molten salt after heat exchange can enter the molten salt tank 311 for storage. When it is necessary to quickly increase the power generation power of the coal-fired unit 20, the molten salt in the molten salt tank 311 can be released and flow in the molten salt circulation pipeline 31.

[0033] For example, the number of the heat exchangers 33 can be three, four, five, six or more than seven. In some specific examples, as Figure 1 shown in the figure, the number of the heat exchangers 33 is three. The heat exchangers 33 are provided with a molten salt flow channel and a water flow channel for heat exchange with each other. The heated molten salt can sequentially enter the molten salt flow channels in the multiple heat exchangers 33 and exchange heat with the liquid flowing in the water flow channel entering the heat exchanger 33 in the reverse direction. That is to say, the flowing direction of the molten salt in the molten salt flow channel is opposite to the flowing direction of the liquid in the water flow channel, so as to effectively improve the heat exchange efficiency.

[0034] The liquid in the water flow channel is heated to form steam. The steam flows in the water circulation pipeline 32 to the vicinity of the gas supply pipe 21 and the water supply pipe 22 and exchanges heat with the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22, making it a high-enthalpy working medium, thereby effectively improving the efficiency of the coal-fired unit 20. Further, the molten salt in the molten salt flow channel can circulate in the molten salt circulation pipeline 31, and the liquid in the water flow channel can circulate in the water circulation pipeline 32, so as to form a continuous heat exchange process.

[0035] In this embodiment, when it is necessary to quickly increase the power generation power of the coal-fired unit 20, on the one hand, the pulverized coal prepared in advance and meeting the requirements in the pulverized coal storage bin 11 is instantaneously supplied to the coal-fired furnace of the coal-fired unit 20 through the pulverized coal inlet, so as to quickly increase the load of the coal-fired furnace, thereby quickly increasing the steam production rate of the coal-fired furnace, and further quickly increasing the power generation power of the coal-fired unit 20; on the other hand, the high-temperature molten salt in the molten salt tank 311 is released. The high-temperature molten salt sequentially enters the molten salt flow channels in the multiple heat exchangers 33 and exchanges heat with the liquid flowing in the water flow channel entering the heat exchanger 33 in the reverse direction, heating the liquid in the water flow channel into steam. The steam can exchange heat with the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22, making it a high-enthalpy working medium, thereby directly increasing the temperature of the gas and liquid entering the coal-fired unit 20, and further quickly increasing the response rate and steam production rate of the coal-fired unit 20.

[0036] In addition, since the energy storage and supply system 30 can rapidly increase the temperatures of the gas and liquid entering the coal-fired unit 20, extraction steam can be cut off or reduced, thereby effectively improving the work capacity of the steam turbine and effectively avoiding the problem of a decrease in feed water temperature caused by the reduction of extraction steam, ensuring the stability of the feed water temperature of the coal-fired unit 20.

[0037] According to the peak shaving system 100 of a coal-fired unit of an embodiment of the present invention, by arranging a pulverized coal storage bin system 10, a coal-fired unit 20, and an energy storage and supply system 30 in the peak shaving system 100 of a coal-fired unit, the pulverized coal storage bin system 10 includes a pulverized coal storage bin 11 for storing pulverized coal. The coal-fired unit 20 has a pulverized coal inlet, a gas supply pipe 21, a water supply pipe 22, and a flue gas discharge pipe 23. The pulverized coal inlet is communicated with the pulverized coal storage bin 11. The energy storage and supply system 30 includes a molten salt circulation pipeline 31, a water circulation pipeline 32, and a plurality of heat exchangers 33. A molten salt tank 311 and a heat accumulator 312 are connected in series on the molten salt circulation pipeline 31. The heat accumulator 312 is connected to the flue gas discharge pipe 23 and is used to heat the molten salt in the heat accumulator 312 with the flue gas discharged through the flue gas discharge pipe 23. The heat exchanger 33 includes a molten salt flow channel and a water flow channel for heat exchange with each other. The molten salt flow channels of the plurality of heat exchangers 33 are sequentially connected in series on the molten salt circulation pipeline 31, and the water flow channels of the plurality of heat exchangers 33 are sequentially connected in series on the water circulation pipeline 32. The water circulation pipeline 32 is configured to perform heat exchange with the gas supply pipe 21 and the water supply pipe 22 to heat the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22, and can rapidly increase the power generation of the coal-fired unit 20 in a short time to adapt to the change of the grid load, thereby ensuring the stability of the power system.

[0038] In an embodiment of the present invention, as Figure 1 shown, the plurality of heat exchangers 33 include a superheater 331, an evaporator 332, and a preheater 333. On the molten salt circulation pipeline 31, the superheater 331, the evaporator 332, and the preheater 333 are sequentially connected in series along the flowing direction of the molten salt in the molten salt circulation pipeline 31. On the water circulation pipeline 32, the preheater 333, the evaporator 332, and the superheater 331 are sequentially connected in series along the flowing direction of the water in the water circulation pipeline 32.

[0039] In some specific examples, as Figure 1 shown, the molten salt in the molten salt circulation pipeline 31 can flow into the molten salt flow channels of the superheater 331, the evaporator 332, and the preheater 333 in sequence. The liquid in the water circulation pipeline 32 can flow into the water flow channels of the preheater 333, the evaporator 332, and the superheater 331 in this way. The liquid in the water circulation pipeline 32 can exchange heat with the molten salt in the molten salt circulation pipeline 31 in the plurality of heat exchangers 33.

[0040] Further, in the preheater 333, the liquid in the water flow channel can be preheated to form saturated water. In the evaporator 332, the saturated water in the water flow channel can be heated to form saturated vapor. In the superheater 331, the saturated vapor in the water flow channel can be heated to form superheated vapor. Then, the superheated vapor can flow in the water circulation pipeline 32 and exchange heat with the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22.

[0041] It should be noted that water reaching the saturation temperature is called "saturated water". When heating continues without a change in temperature, water vapor with water is produced, called "wet saturated vapor". Until all the water turns into vapor, it is called "dry saturated vapor" or simply "saturated vapor" for short. If the saturated vapor is further heated at the same pressure, the temperature begins to rise above the saturation temperature, and the vapor at this time is called "superheated vapor". The superheated vapor has sufficient heat to ensure the heat exchange efficiency with the gas in the gas supply pipe 21 and the liquid in the water supply pipe 22.

[0042] In this embodiment, by setting the multiple heat exchangers 33 as the superheater 331, the evaporator 332, and the preheater 333, on the molten salt circulation pipeline 31, the superheater 331, the evaporator 332, and the preheater 333 are connected in series in sequence along the flowing direction of the molten salt in the molten salt circulation pipeline 31. On the water circulation pipeline 32, the preheater 333, the evaporator 332, and the superheater 331 are connected in series in sequence along the flowing direction of the water in the water circulation pipeline 32, which can realize the gradual heat exchange between the molten salt circulation pipeline 31 and the water circulation pipeline 32, ensure the cascade utilization of energy, and thus effectively improve the heat exchange efficiency and the stability of the heat exchange process.

[0043] In an embodiment of the present invention, as Figure 1 shown, the molten salt tank 311 includes a high-temperature molten salt tank 3111 and a low-temperature molten salt tank 3112. The inlet of the high-temperature molten salt tank 3111 is connected to the molten salt outlet of the heat storage device 312, and the outlet of the low-temperature molten salt tank 3112 is connected to the molten salt inlet of the heat storage device 312. The multiple heat exchangers 33 are connected in series in sequence between the outlet of the high-temperature molten salt tank 3111 and the inlet of the low-temperature molten salt tank 3112.

[0044] In some specific examples, as Figure 1 shown, a molten salt output pipe 313 and a molten salt input pipe 314 are provided in the molten salt circulation pipeline 31. One end of the molten salt output pipe 313 is connected to the inlet of the molten salt tank 311, and the other end of the inlet of the molten salt tank 311 is connected to the molten salt outlet of the heat storage device 312. One end of the molten salt input pipe 314 is connected to the outlet of the low-temperature molten salt tank 3112, and the other end of the outlet of the low-temperature molten salt tank 3112 is connected to the molten salt inlet of the heat storage device 312. The superheater 331, the evaporator 332, and the preheater 333 are connected in series in sequence between the outlet of the high-temperature molten salt tank 3111 and the inlet of the low-temperature molten salt tank 3112.

[0045] After the molten salt in the molten salt circulation pipeline 31 flows into the heat storage tank 312 and is heated by the flue gas, it flows into the high-temperature molten salt tank 3111, the superheater 331, the evaporator 332, and the preheater 333 in sequence through the molten salt output pipe 313, and exchanges heat with the liquid in the water circulation pipeline 32 in multiple heat exchangers 33. After that, it flows into the low-temperature molten salt tank 3112 and finally flows back into the heat storage tank 312 through the molten salt input pipe 314. Thus, the molten salt can complete the cyclic flow in the molten salt circulation pipeline 31.

[0046] In this embodiment, by providing a high-temperature molten salt tank 3111 and a low-temperature molten salt tank 3112 in the molten salt tank 311, the inlet of the high-temperature molten salt tank 3111 is connected to the molten salt outlet of the heat storage tank 312, the outlet of the low-temperature molten salt tank 3112 is connected to the molten salt inlet of the heat storage tank 312, and multiple heat exchangers 33 are connected in series between the outlet of the high-temperature molten salt tank 3111 and the inlet of the low-temperature molten salt tank 3112, which can optimize the structural layout of the molten salt circulation pipeline 31, thereby helping to maintain the temperature difference of the molten salt at different stages, and further effectively improving the energy transfer efficiency.

[0047] In one embodiment of the present invention, as Figure 1 shown, a high-temperature molten salt pump 315 and a low-temperature molten salt pump 316 are also connected in series on the molten salt circulation pipeline 31. The high-temperature molten salt pump 315 is connected between the outlet of the high-temperature molten salt tank 3111 and the heat exchanger 33, and the low-temperature molten salt pump 316 is connected between the outlet of the low-temperature molten salt tank 3112 and the heat storage tank 312.

[0048] In some specific examples, as Figure 1 shown, the high-temperature molten salt pump 315 is connected between the outlet of the high-temperature molten salt tank 3111 and the superheater 331, and the low-temperature molten salt pump 316 is connected in series on the molten salt input pipe 314. By adjusting the high-temperature molten salt pump 315, the flow rate and flow volume of the high-temperature molten salt flowing from the high-temperature molten salt tank 3111 to multiple heat exchangers 33 can be controlled. By adjusting the low-temperature molten salt tank 3112, the flow rate and flow volume of the low-temperature molten salt flowing from the low-temperature molten salt tank 3112 to the heat storage tank 312 can be controlled.

[0049] In this embodiment, by connecting a high-temperature molten salt pump 315 and a low-temperature molten salt pump 316 in series on the molten salt circulation pipeline 31, with the high-temperature molten salt pump 315 connected between the outlet of the high-temperature molten salt tank 3111 and the heat exchanger 33, and the low-temperature molten salt pump 316 connected between the outlet of the low-temperature molten salt tank 3112 and the heat storage tank 312, the flow rate and flow volume of the molten salt can be accurately controlled, so that the heat exchange rate between the molten salt circulation pipeline 31 and the water circulation pipeline 32 can be precisely controlled according to actual needs, and further the flexibility and reliability of the molten salt circulation pipeline 31 can be effectively improved.

[0050] In one embodiment of the present invention, as Figure 1As shown, the energy storage and supply system 30 further includes a heat exchange box 34 and heat exchange branch pipes 35. The heat exchange box 34 has a water channel and a gas channel for heat exchange with each other. The water channel is connected in series to the water circulation pipeline 32, and the gas channel is connected in series to the gas supply pipe 21. Both ends of the heat exchange branch pipes 35 are connected to the water circulation pipeline 32 and are arranged between the heat exchange box 34 and the superheater 331. A part of the heat exchange branch pipes 35 is wound around the water supply pipe 22 to exchange heat with the water supply pipe 22.

[0051] In some specific examples, such as Figure 1 As shown, a three-way valve is connected in series to the water circulation pipeline 32. The three-way valve is arranged between the heat exchange box 34 and the superheater 331. Further, one end of the heat exchange branch pipes 35 is connected to the three-way valve, and the other end of the heat exchange branch pipes 35 is directly connected to the water circulation pipeline 32. The connection point of the other end of the heat exchange branch pipes 35 and the water circulation pipeline 32 is located between the three-way valve and the heat exchange box 34.

[0052] The liquid in the water circulation pipeline 32 forms superheated steam after passing through multiple heat exchangers 33. The superheated steam flows from the superheater 331 to the three-way valve and is split into two parts after being split in the three-way valve. One part of the superheated steam flows to the heat exchange branch pipes 35 and exchanges heat with the liquid in the water supply pipe 22, thereby effectively increasing the temperature of the liquid entering the coal-fired unit 20. After that, this part of the steam enters the water circulation pipeline 32 to be mixed with the other part of the superheated steam, and then flows into the water channel in the heat exchange box 34 and exchanges heat with the gas in the gas channel in the heat exchange box 34, thereby effectively increasing the temperature of the gas entering the coal-fired unit 20.

[0053] In addition, a feed water bypass pipe 321 is also provided in the water circulation pipeline 32. One end of the feed water bypass pipe 321 is connected to the outlet of the water channel, and the other end of the feed water bypass pipe 321 is connected to the inlet of the preheater 333. Further, a feed water bypass valve 3211 is connected in series to the feed water bypass pipe 321. The superheated steam condenses after heat exchange in the heat exchange box 34 and then flows back to the preheater 333 through the feed water bypass pipe 321, thus forming a recycling. By adjusting the opening of the feed water bypass valve 3211, the flow rate and flow volume of the liquid in the feed water bypass pipe 321 can be controlled.

[0054] In this embodiment, by providing the heat exchange box 34 in the energy storage and supply system 30, the heat exchange box 34 has a water channel and a gas channel for heat exchange with each other. The water channel is connected in series to the water circulation pipeline 32, and the gas channel is connected in series to the gas supply pipe 21, which can effectively improve the heat exchange efficiency between the water circulation pipeline 32 and the gas supply pipe 21. By providing the heat exchange branch pipes 35 in the energy storage and supply system 30, and connecting both ends of the heat exchange branch pipes 35 to the water circulation pipeline 32 and arranging them between the heat exchange box 34 and the superheater 331, and winding a part of the heat exchange branch pipes 35 around the water supply pipe 22 to exchange heat with the water supply pipe 22, the heat exchange efficiency between the heat exchange branch pipes 35 and the water supply pipe 22 can be effectively improved.

[0055] In one embodiment of the present invention, as Figure 1 shown, the energy storage and supply system 30 further includes a first control valve 322, a second control valve 323, and a third control valve 351. The first control valve 322 is connected in series to the water circulation pipeline 32 and is located between the superheater 331 and the heat exchange branch pipe 35; the second control valve 323 is connected in series to the water circulation pipeline 32 and is located between the heat exchange tank 34 and the heat exchange branch pipe 35; the third control valve 351 is connected in series to the heat exchange branch pipe 35.

[0056] In some specific examples, as Figure 1 shown, the first control valve 322 is located between the superheater 331 and the three-way valve. By adjusting the first control valve 322, the flow rate and flow volume of the gas flowing through the three-way valve can be controlled. By adjusting the second control valve 323, the flow rate and flow volume of the gas flowing through the water channel in the heat exchange tank 34 can be controlled. By adjusting the third control valve 351, the flow rate and flow volume of the gas flowing through the heat exchange branch pipe 35 can be controlled. That is to say, by adjusting the first control valve 322, the second control valve 323, and the third control valve 351, the heat exchange efficiency between the water circulation pipeline 32 and the gas supply pipe 21 and the heat exchange efficiency between the heat exchange branch pipe 35 and the water supply pipe 22 can be controlled.

[0057] In this embodiment, by providing the first control valve 322, the second control valve 323, and the third control valve 351 in the energy storage and supply system 30. The first control valve 322 is connected in series to the water circulation pipeline 32 and is located between the superheater 331 and the heat exchange branch pipe 35, the second control valve 323 is connected in series to the water circulation pipeline 32 and is located between the heat exchange tank 34 and the heat exchange branch pipe 35, and the third control valve 351 is connected in series to the heat exchange branch pipe 35, the heat exchange efficiency between the water circulation pipeline 32 and the gas supply pipe 21 and the heat exchange efficiency between the heat exchange branch pipe 35 and the water supply pipe 22 can be precisely adjusted, thereby effectively improving the flexibility and reliability of the water circulation pipeline 32.

[0058] In one embodiment of the present invention, as Figure 1 shown, the energy storage and supply system 30 further includes a make-up water pipe 36 and a make-up water pump 361. The make-up water pump 361 is connected in series to the make-up water pipe 36, and the outlet end of the make-up water pipe 36 is connected to the preheater 333.

[0059] It should be noted that the liquid in the water circulation management will have a certain amount of loss due to evaporation, leakage, etc. Therefore, when the water circulation pipeline 32 is working, it is necessary to timely supplement the liquid into the water circulation pipeline 32, so as to avoid the decline of the system performance or the damage of the equipment caused by insufficient liquid volume, and ensure the long-term stable operation of the water circulation pipeline 32.

[0060] In some specific examples, as Figure 1As shown, one end of the makeup water pipe 36 is connected to the preheater 333, and the liquid in the makeup water pipe 36 can flow into the preheater 333, so as to supplement the liquid in the water circulation pipeline 32 in a timely manner. Further, a makeup water pump 361 is connected in series on the makeup water pipe 36. By adjusting the makeup water pump 361, the flow rate and flow volume of the liquid in the makeup water pipe 36 can be controlled, so as to control the rate of supplementing the liquid to the water circulation pipeline 32.

[0061] In this embodiment, by arranging the makeup water pipe 36 and the makeup water pump 361 in the energy storage and supply system 30, the makeup water pump 361 is connected in series on the makeup water pipe 36, and the outlet end of the makeup water pipe 36 is connected to the preheater 333, the liquid in the water circulation pipeline 32 can be supplemented in a timely manner and the rate of liquid supplement can be controlled, thereby effectively improving the stability and reliability of the water circulation pipeline 32.

[0062] In an embodiment of the present invention, as Figure 1 shown, the pulverized coal storage bin system 10 further includes a screw conveyor 12, a crusher 13, a dust filtering box 14 and a suction fan 15. The outlet of the screw conveyor 12 is connected to the inlet of the crusher 13. A screening plate is provided in the dust filtering box 14. The inlet of the dust filtering box 14 is connected to the outlet of the crusher 13. The pulverized coal outlet of the dust filtering box 14 is connected to the pulverized coal storage bin 11, and the gas outlet of the dust filtering box 14 is connected to the inlet of the suction fan 15.

[0063] In some specific examples, as Figure 1 shown, the output end of the screw conveyor 12 is connected to the inlet of the crusher 13 through a conveyor belt 16, the output end of the crusher 13 is connected to the inlet of the dust filtering box 14 through a conveyor belt 16, the rear end of the dust filtering box 14 is connected to the air inlet of the suction fan 15 through a pipeline 17, and the output end of the dust filtering box 14 is connected to the input end of the pulverized coal storage bin 11 through a conveyor belt 16.

[0064] The coal blocks are conveyed by the screw conveyor 12. During the conveying process of the screw conveyor 12, the coal blocks will be squeezed against each other, so as to achieve a preliminary crushing effect. Then, the coal blocks are conveyed to the crusher 13 through the conveyor belt. The crusher 13 uses crushing rollers to thoroughly crush the coal blocks. After that, the coal is conveyed to the dust filtering box 14 through the conveyor belt.

[0065] By starting the suction fan 15, the suction fan 15 generates suction force, so that the outside air enters the inside of the dust filtering box 14 to carry away the dust. At the same time, a screening plate is also provided inside the dust filtering box 14, and the screening plate can screen the coal and convey the qualified coal to the inside of the pulverized coal storage bin 11 for storage.

[0066] In this embodiment, a screw conveyor 12, a crusher 13, a dust filter box 14, and a suction fan 15 are provided in the pulverized coal storage bin system 10. The outlet of the screw conveyor 12 is connected to the inlet of the crusher 13. A screening plate is provided in the dust filter box 14. The inlet of the dust filter box 14 is connected to the outlet of the crusher 13. The pulverized coal outlet of the dust filter box 14 is connected to the pulverized coal storage bin 11. The gas outlet of the dust filter box 14 is connected to the inlet of the suction fan 15, which can effectively improve the efficiency of pulverized coal preparation, thereby effectively improving the reliability of the pulverized coal storage bin system 10.

[0067] In one embodiment of the present invention, as Figure 1 shown, the pulverized coal storage bin 11 is provided with a level detection device 111 for detecting the height of the pulverized coal in the pulverized coal storage bin 11.

[0068] It should be noted that the level detection device 111 can monitor the pulverized coal storage volume in the pulverized coal storage bin 11 by detecting the height of the pulverized coal in the pulverized coal storage bin 11, thereby reducing the need for manual inspection and improving work efficiency. In addition, monitoring the pulverized coal storage volume in the pulverized coal storage bin 11 helps to more accurately arrange the pulverized coal preparation plan, avoiding affecting production due to insufficient pulverized coal or causing resource waste due to excessive storage.

[0069] In this embodiment, by providing a level detection device 111 for detecting the height of the pulverized coal in the pulverized coal storage bin 11 in the pulverized coal storage bin 11, the pulverized coal storage volume in the pulverized coal storage bin 11 can be effectively monitored, the need for manual inspection can be reduced, and thus work efficiency can be improved. In addition, inventory management can be optimized based on the pulverized coal storage volume in the pulverized coal storage bin 11, so as to ensure that the pulverized coal storage bin system 10 can supply coal to the coal-fired unit 20 in a timely and sufficient manner, and further effectively improve the stability and reliability of the peak shaving system 100 of the coal-fired unit.

[0070] In one embodiment of the present invention, as Figure 1 shown, the level detection device 111 includes: a high-level alarm 1111 and a low-level alarm 1112. The high-level alarm 1111 is provided at the top of the bin of the pulverized coal storage bin 11, and the low-level alarm 1112 is provided at the bottom of the bin.

[0071] In some specific examples, as Figure 1 shown, the high-level alarm 1111 is installed at the top of the bin of the pulverized coal storage bin 11 for monitoring whether the pulverized coal in the bin of the pulverized coal storage bin 11 is close to or reaches the maximum capacity. The low-level alarm 1112 is installed at the bottom of the bin of the pulverized coal storage bin 11 for monitoring whether the pulverized coal in the bin of the pulverized coal storage bin 11 is close to or less than the minimum capacity.

[0072] When the height of the pulverized coal in the silo of the pulverized coal storage bin 11 reaches the preset high threshold value, the high-level alarm 1111 will trigger an alarm to remind the operator to take measures, such as stopping the feeding or adjusting the feeding speed, so as to prevent the pulverized coal from overflowing. When the height of the pulverized coal in the silo of the pulverized coal storage bin 11 drops to the preset low threshold value, the low-level alarm 1112 will issue an alarm to prompt the operator to supplement the pulverized coal, so as to avoid the problem of insufficient pulverized coal.

[0073] In this embodiment, by arranging the high-level alarm 1111 and the low-level alarm 1112 in the level detection device 111, with the high-level alarm 1111 arranged at the top of the silo of the pulverized coal storage bin 11 and the low-level alarm 1112 arranged at the bottom of the silo, it can not only effectively simplify the level detection device 111, thereby effectively reducing the cost, but also effectively optimize the operation process, thereby effectively improving the management efficiency.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 a limitation of the present invention.

[0075] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0076] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0078] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A coal-fired unit peak load regulation system, characterized in that: include: A pulverized coal storage bin system, comprising a pulverized coal storage bin for storing pulverized coal; A coal-fired unit having a pulverized coal inlet, an air supply pipe, a water supply pipe and a flue gas discharge pipe, wherein the pulverized coal inlet is connected to the pulverized coal storage bin; The energy storage and supply system comprises: a molten salt circulation pipeline, a water circulation pipeline and a plurality of heat exchangers, wherein a molten salt tank and a heat storage device are connected in series on the molten salt circulation pipeline, and the heat storage device is connected to the flue gas exhaust pipe so as to allow the flue gas discharged through the flue gas exhaust pipe to heat the molten salt in the heat storage device, and the heat exchanger comprises a molten salt flow channel and a water flow channel for exchanging heat with each other, the molten salt flow channels of a plurality of the heat exchangers are connected in series on the molten salt circulation pipeline, and the water flow channels of a plurality of the heat exchangers are connected in series on the water circulation pipeline, and the water circulation pipeline is configured to exchange heat with the gas supply pipe and the water supply pipe so as to heat the gas in the gas supply pipe and the liquid in the water supply pipe.

2. The peak load regulation system of coal-fired units according to claim 1, characterized in that: The multiple heat exchangers include a superheater, an evaporator and a preheater. On the molten salt circulation pipeline, the superheater, the evaporator and the preheater are connected in series in sequence along the flow direction of the molten salt in the molten salt circulation pipeline. On the water circulation pipeline, the preheater, the evaporator and the superheater are connected in series in sequence along the flow direction of the water in the water circulation pipeline.

3. The peak load regulation system of coal-fired units according to claim 2, characterized in that: The molten salt tank includes a high-temperature molten salt tank and a low-temperature molten salt tank. The inlet of the high-temperature molten salt tank is connected to the molten salt outlet of the heat storage device, and the outlet of the low-temperature molten salt tank is connected to the molten salt inlet of the heat storage device. The multiple heat exchangers are serially connected between the outlet of the high-temperature molten salt tank and the inlet of the low-temperature molten salt tank.

4. The peak load regulation system of coal-fired units according to claim 3, characterized in that: A high-temperature molten salt pump and a low-temperature molten salt pump are also connected in series on the molten salt circulation pipeline. The high-temperature molten salt pump is connected between the outlet of the high-temperature molten salt tank and the heat exchanger, and the low-temperature molten salt pump is connected between the outlet of the low-temperature molten salt tank and the heat storage.

5. The peak load regulation system of coal-fired units according to claim 2, characterized in that: The energy storage and supply system also includes: A heat exchange box, wherein the heat exchange box has a water channel and an air channel for mutual heat exchange, the water channel is serially connected to the water circulation pipeline, and the air channel is serially connected to the air supply pipe; A heat exchange branch pipe, both ends of which are connected to the water circulation pipeline and arranged between the heat exchange box and the superheater, and a part of the heat exchange branch pipe is wound around the water supply pipe to exchange heat with the water supply pipe.

6. The peak load regulation system of coal-fired units according to claim 5, characterized in that: The energy storage and supply system also includes: A first control valve, connected in series to the water circulation pipeline and located between the superheater and the heat exchange branch pipe; A second control valve is serially connected to the water circulation pipeline and is located between the heat exchange box and the heat exchange branch pipe; The third control valve is connected in series to the heat exchange branch pipe.

7. The peak load regulation system of coal-fired units according to claim 2, characterized in that: The energy storage and supply system further includes: a water replenishment pipe and a water replenishment pump, wherein the water replenishment pump is connected in series to the water replenishment pipe, and an outlet end of the water replenishment pipe is connected to the preheater.

8. The peak load regulation system of coal-fired units according to claim 1, characterized in that: The pulverized coal storage bin system also includes: a screw conveyor, a crusher, a dust filter box and a suction fan. The outlet of the screw conveyor is connected to the inlet of the crusher. A screening plate is provided in the dust filter box. The inlet of the dust filter box is connected to the outlet of the crusher. The pulverized coal outlet of the dust filter box is connected to the pulverized coal storage bin. The gas outlet of the dust filter box is connected to the inlet of the suction fan.

9. The peak load regulation system of coal-fired units according to claim 1, characterized in that: The pulverized coal storage bin is provided with a material level detection device for detecting the height of the pulverized coal in the pulverized coal storage bin.

10. The peak load regulation system of coal-fired units according to claim 9, characterized in that: The material level detection device comprises: a high material level alarm and a low material level alarm, wherein the high material level alarm is arranged at the top of the silo of the coal powder storage silo, and the low material level alarm is arranged at the bottom of the silo.

Images