A method for rapidly increasing load of a coal-fired power generation unit

Abstract

The present invention discloses a heat storage device, an energy supply system and a method for rapidly increasing the load of a coal-fired power generation unit, and relates to the technical field of rapid peak regulation of coal-fired power generation. Aiming at the problem that the steam production rate of the boiler of a coal-fired power generation unit is insufficient under low-load operation conditions, resulting in the limited load change rate of the unit, the present invention provides a high-temperature and high-pressure water heat storage device and its energy supply system that can improve the rapid load increase capacity of boilers of various grades of coal-fired power generation units. When the unit is in stable operation or load reduction at medium and high loads, the abundant steam energy is stored in the high-temperature and high-pressure water heat storage device through indirect heat exchange. When the unit is in a low-load condition and needs to climb rapidly, the water heat storage device directly supplies high-enthalpy steam and saturated water to the boiler steam-water system. Since there is no fuel heat release and working medium heat absorption process in the energy supply process, the problem of boiler heat transfer hysteresis is fundamentally solved, thereby directly and rapidly improving the boiler steam production rate and realizing rapid load increase of the coal-fired power generation unit.

Description

Technical Field

[0001] The present invention relates to the technical field of rapid peak regulation of coal-fired power generation, and in particular to a heat storage device, an energy supply system and a method for rapid load increase of a coal-fired power generation unit. Background Art

[0002] With the continuous increase in the installed capacity and proportion of new energy power generation such as wind power and photovoltaic power in my country, the regulation gap for stable operation of the power grid has increased significantly, especially under extreme weather conditions. Coal-fired power units are required to have a high and rapid load response capability to cope with the occurrence of large-scale wind and light loss conditions and ensure the safe and stable operation of the power grid. The existing coal-fired power generation units in my country have insufficient load change rate (usually 1.0%~2.0% of rated load / minute), which poses serious challenges to the safe and stable operation of new power systems with a high proportion of renewable energy in the future.

[0003] The operation of coal-fired power plant boilers involves complex heat and mass transfer processes. For this reason, the boiler system has large thermal inertia and strong hysteresis. When the unit receives a dispatch instruction and needs to ramp up quickly, the boiler's untimely energy supply leads to insufficient steam production response rate, which seriously restricts the unit's variable load response rate. At present, most coal-fired power generation unit peak-shaving technologies based on energy storage devices (molten salt storage tanks, electrode boilers, steam accumulators, etc.) are designed to achieve the "thermal and electric decoupling" of the unit, and cannot completely solve the problem of insufficient boiler steam production in the initial stage of the unit's load increase.

[0004] In addition, how the energy storage device can conveniently and efficiently obtain high-quality energy from the unit, and how the energy released by the energy storage device can be safely and effectively matched with the thermal system of the unit to ensure the safe operation of the unit and achieve rapid energy supply and increased variable load response rate of the boiler are the core issues and key difficulties of the rapid and flexible peak-shaving technology of coal-fired power units. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a heat storage device and an energy supply system to solve the problem of insufficient steam production by the boiler in the initial stage of load increase of the existing coal-fired power generation unit.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention provides a heat storage device, including a shell, a heat exchange unit is arranged in the shell, and the heat exchange unit can be in the form of coil heat exchange, serpentine heat exchange, plate heat exchange, etc. A circulation cover is arranged outside the heat exchange unit, and the density of the heated working medium in the circulation cover decreases and the temperature increases, while the temperature of the working medium outside the circulation cover is lower than the temperature of the working medium in the circulation cover. Under the action of the density difference, the working medium in the circulation cover flows upward, and the working medium outside the circulation cover flows into the circulation cover from the bottom of the circulation cover under the action of negative pressure to be heated, thereby improving the fluid in the heat storage device. The circulation cover is a trumpet-shaped or cylindrical shape that gradually contracts and expands. The circulation cover is vertically arranged, and the upper and lower ends of the circulation cover are arranged with openings. The water inside the circulation cover will flow upward and diffuse after being heated by the heat exchange unit. The low-temperature water at the lower opening of the circulation cover will flow upward into the circulation cover for heat exchange under the action of pressure. In this way, the water in various parts of the heat storage device is uniformly and quickly heated. A gas collecting chamber is arranged on the shell.

[0007] The shell is connected with a water injection pipeline, which is connected with the boiler system water supply main or condensate pipe. When the on-off valve 1 is opened, the water injection pipeline passes the boiler supercooled water into the heat storage device to a specified water level; the gas collection chamber is connected with an energy release main pipe; the inlet of the energy release main pipe is connected with the top of the gas collection chamber, and the outlet is connected with the steam inlet of the external steam-water separator. When the on-off valve 2 is opened, the energy release main pipe guides the steam in the gas collection chamber of the heat storage device, and passes it into the external steam-water separator after throttling and reducing the pressure by the pressure reducing valve;

[0008] One end of the heat exchange unit is connected to the heating inlet main pipe through an inlet branch pipe, and the other end of the heat exchange unit is connected to the heating outlet main pipe through an outlet branch pipe;

[0009] The heating inlet main pipe is also provided with a mixing branch pipe, and the mixing branch pipe is communicated with the interior of the shell.

[0010] A heating inlet main pipe is provided with an opening and closing valve 5, the heating inlet main pipe is connected to the steam turbine extraction pipeline or other steam heat source, and a plurality of inlet branches are led out from the end of the heating inlet main pipe; a stop valve 1 is provided on the inlet branch pipe and is connected to the heat exchange unit; the stop valve 1 is used to adjust the pressure resistance of the inlet branch pipe to ensure that the steam flow rate flowing in each inlet branch pipe is consistent; when the valve 5 is opened, the heating inlet main pipe and the inlet branch pipe uniformly pass the high-temperature steam into the heat exchange unit;

[0011] The outlet of the heat exchange unit is provided with an outlet branch pipe, on which a stop valve 2 is provided and the outlet branch pipe is collected at the front end of the heating outlet main pipe; the heating outlet main pipe is provided with an opening and closing valve 6 and is connected to the boiler heating pipeline or the auxiliary steam pipeline, and the heating outlet main pipe leads out the steam after heat exchange when the valve 6 is opened; the inlet of the heating inlet main pipe can be connected to a certain stage of the steam extraction pipeline of the turbine, or the main steam pipeline, or other steam heat sources, as long as the temperature of the heat source steam is higher than the set value of the heat storage working medium, and there is no requirement for the pressure of the heat source steam.

[0012] Preferably, the water injection pipeline is provided with an opening and closing valve 1; the energy release main pipe is provided with an opening and closing valve 2 and a pressure reducing valve;

[0013] The heating inlet main pipe is provided with an opening and closing valve five; the heating outlet main pipe is provided with an opening and closing valve six;

[0014] The inlet branch pipe is provided with a first stop valve, the outlet branch pipe is provided with a second stop valve, and the mixing branch pipe is provided with a third stop valve.

[0015] Preferably, a safety valve and / or a liquid level meter and / or a thermometer and / or a pressure gauge are also provided on the housing.

[0016] A second aspect of the present invention provides an energy supply system for rapidly increasing the load of a coal-fired power generation unit, comprising any of the aforementioned heat storage devices.

[0017] Preferably, it also includes a water-cooled wall, a steam drum or a steam-water separator, an external steam-water separator, a water storage tank, an energy release branch 1 and an energy release branch 2;

[0018] The inlet end of the external steam-water separator is connected to the heat storage device, and the first outlet end of the external steam-water separator is connected to the outlet pipe of the steam drum or the steam-water separator through the energy release branch one; the second outlet end of the external steam-water separator is connected to the lower end of the water-cooled wall through the energy release branch two; a water storage tank is provided on the energy release branch two, and the water storage tank is used to store saturated water separated by the external steam-water separator; the upper end of the water-cooled wall is connected to the steam drum or the steam-water separator.

[0019] Preferably, the energy release branch one is provided with an on-off valve three and a check valve one; the energy release branch two is provided with an on-off valve four and a check valve two; an energy release branch pipe one is provided with an on-off valve three and a check valve one, the inlet of the energy release branch pipe one is connected to the steam outlet of the external steam-water separator, and its outlet is connected to the boiler superheated steam pipeline (coated superheater or low-temperature superheater), and the energy release branch one passes the separated dry steam into the boiler superheater for superheating when the on-off valve three is opened; an energy release branch pipe two is provided with an on-off valve four and a check valve two, the inlet of the energy release branch pipe two is connected to the water storage tank, and its outlet is connected to the boiler downcomer or the water-cooled wall inlet header, and the energy release branch two passes the water in the water storage tank into the boiler steam-water system when the on-off valve four is opened.

[0020] Preferably, the flow rate of the working fluid for releasing energy of the heat storage device is jointly controlled by the opening degree of the on-off valve three of the energy release branch one and the opening degree of the on-off valve four of the energy release branch two.

[0021] Preferably, it also includes an automatic control system, which is used to control the automatic operation of the energy supply system.

[0022] A third aspect of the present invention provides a method for rapidly increasing the load of a coal-fired power generation set. When the coal-fired power generation set is operating stably at medium load (50% to 80% of rated load), stably at high load (80% to 100% of rated load), or operating at reduced load, the surplus steam energy is stored in a heat storage device. When the unit is in a low load condition and needs to rapidly increase the load, the heat storage device directly supplies high enthalpy steam and saturated water to the boiler steam-water system, thereby directly and rapidly increasing the boiler steam yield and realizing rapid load increase of the coal-fired power generation set.

[0023] A fourth aspect of the present invention provides a method for rapidly increasing the load of a coal-fired power generation unit, the method comprising the following steps:

[0024] (1) Fill with water

[0025] Open the first on-off valve, close the third stop valve, use the water injection pipeline to fill a certain amount of boiler supercooled water into the heat storage device to the filling water level, close the first on-off valve, and the water filling is completed;

[0026] (2) Charging

[0027] Open the opening and closing valve 5 and the opening and closing valve 6; open the stop valve 1 and the stop valve 2, and the high-temperature heating steam enters the heat exchange unit along the heating inlet main pipe through the inlet branch pipe, and transfers heat to the water in the device in the form of non-contact heat exchange; when the working medium temperature and pressure in the heat storage device rise to the set value, close the opening and closing valve 5 and the opening and closing valve 6, and the charging is completed;

[0028] (3) Insulation

[0029] After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is lower than the set pressure value by a certain value, the opening and closing valves 5 and 6 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valves 5 and 6 are closed.

[0030] (4) Energy release

[0031] When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, and the opening and closing valves 2, 3 and 4 are opened. The steam in the air collecting chamber above the heat storage device enters the pressure reducing valve along the energy release main pipe. The pressure reducing valve reduces the high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 1 for superheating and direct steam production. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall along the energy release branch 2. By increasing the feed water enthalpy, the heat transfer temperature difference is reduced and the steam production rate is accelerated.

[0032] A fifth aspect of the present invention provides a method for rapidly increasing the load of a coal-fired power generation unit. When the high-temperature heating steam directly meets the steam quality requirements of the gas collecting chamber, the method comprises the following steps:

[0033] (1) Charging

[0034] Close the opening and closing valve 1 and the opening and closing valve 6; close the stop valve 1 and the stop valve 2, open the opening and closing valve 5 and the stop valve 3, and the high-temperature heating steam directly enters the heat storage device along the heating inlet main pipe through the mixing branch pipe. When the working medium temperature and pressure in the heat storage device reach the set value, close the opening and closing valve 5 and the stop valve 3, and the charging is completed;

[0035] (2) Insulation

[0036] After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is 0.1MPa lower than the set pressure value, the opening and closing valve 5 and the stop valve 3 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valve 5 and the stop valve 3 are closed.

[0037] (3) Energy release

[0038] When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, and the opening and closing valves 2, 3 and 4 are opened. The steam in the air collecting chamber above the heat storage device enters the pressure reducing valve along the energy release main pipe. The pressure reducing valve reduces the high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 1 for superheating and direct steam production. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall along the energy release branch 2. By increasing the feed water enthalpy, the heat transfer temperature difference is reduced and the steam production rate is accelerated.

[0039] Beneficial effects of the present invention:

[0040] (1) When the coal-fired power generation unit needs to change load quickly, the present invention directly and quickly supplies high-temperature steam and high-enthalpy saturated hot water to the boiler water circulation system through the heat storage device, thereby avoiding the boiler heat transfer delay, directly and quickly improving the boiler steam production rate response rate, and thus greatly improving the unit's rapid load increase response capability;

[0041] (2) The energy supply system of the present invention adopts an external steam-water separator, which effectively solves the problem that the high-temperature and high-pressure working fluid cannot enter the boiler superheater pipeline and the boiler water-cooled wall water circulation due to the formation of a steam-water mixture after decompression, thereby ensuring the safe and efficient matching of the energy supply system and the boiler steam-water system;

[0042] (3) The heat storage device of the present invention can adopt an indirect heat exchange method, thereby broadening the optional range of steam heat sources, so that high-temperature but low-pressure steam can also be used as charging steam for the heat storage device, avoiding the energy waste caused by using high-pressure main steam before the steam turbine for heating; in emergency situations, a direct heat exchange method can also be used to directly charge the heat storage device with steam that meets the requirements;

[0043] (4) A circulation cover is arranged outside the heat exchange unit of the heat storage device of the present invention. The flow of the heated working medium in the circulation cover increases the heat transfer efficiency and the heat transfer uniformity of the working medium as a whole, so that the working medium in the device can be quickly and evenly heated and pressurized.

[0044] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a system layout diagram of a preferred embodiment of the present invention.

[0046] Among them: 1. Shell; 2. Circulation cover; 3. Heat exchange unit; 4. Gas collecting chamber; 5. Safety valve; 6. External steam-water separator; 7. Water storage tank; 8. Water-cooled wall; 9. Steam drum or steam-water separator; 10. Water injection pipeline; 11. Energy release main pipe; 12. Energy release branch one; 13. Energy release branch two; 14. Heating inlet main pipe; 15. Inlet branch pipe; 16. Outlet branch pipe; 17. Heating outlet main pipe; 18. Opening and closing valve one; 19. Opening and closing valve two; 20. Pressure reducing valve; 21. Opening and closing valve three; 22. Check valve one; 23. Opening and closing valve four; 24. Check valve two; 25. Opening and closing valve five; 26. Stop valve one; 27. Stop valve two; 28. Opening and closing valve six; 29. ​​Mixing branch pipe; 30. Stop valve three. DETAILED DESCRIPTION

[0047] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0048] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings. Example 1

[0049] like Figure 1 As shown, the present invention provides a heat storage device, including a shell 1, in which a plurality of heat exchange units 3 are arranged. The heat exchange units 3 can be in the form of coil heat exchange, serpentine heat exchange, plate heat exchange, etc. A circulation cover 2 is arranged outside the heat exchange unit 3. The flow of the heated working medium in the circulation cover 2 increases the heat transfer efficiency and the overall heat transfer uniformity of the working medium, so that the working medium in the device can be quickly and evenly heated and pressurized; the circulation cover 2 is a gradually shrinking and expanding trumpet shape or cylindrical shape, and the water inside the circulation cover 2 will flow upward and diffuse after being heated by the heat exchange unit, and the low-temperature water at the lower end of the circulation cover 2 will flow upward into the circulation cover 2 under pressure for heat exchange, and the circulation is continuously continued, so that the water in various parts of the heat storage device of this embodiment is evenly and quickly heated; an air collecting chamber 4 is arranged on the shell 1.

[0050] The shell 1 is connected with a water injection pipeline 10, which is connected with the boiler system water supply main or condensate pipe. When the on-off valve 18 is opened, the water injection pipeline 10 passes the boiler supercooled water into the heat storage device to a specified water level; the gas collecting chamber 4 is connected with an energy release main pipe 11; the inlet of the energy release main pipe 11 is connected with the top of the gas collecting chamber 4, and its outlet is connected with the steam inlet of the external steam-water separator 6. When the on-off valve 19 is opened, the energy release main pipe 11 guides the steam in the gas collecting chamber 4 of the heat storage device, and passes the steam into the external steam-water separator 6 after throttling and reducing the pressure through the pressure reducing valve 20;

[0051] One end of the heat exchange unit 3 is connected to the heating inlet main pipe 14 through an inlet branch pipe 15, and the other end of the heat exchange unit 3 is connected to the heating outlet main pipe 17 through an outlet branch pipe 16;

[0052] The heating inlet main pipe 14 is also provided with a mixing branch pipe 29 , which is communicated with the interior of the shell 1 .

[0053] A heating inlet main pipe 14 is provided with an on-off valve 5 25, and the heating inlet main pipe 14 is connected to a steam turbine extraction pipeline or other steam heat source, and a plurality of inlet branches 15 are led out from the end of the heating inlet main pipe 14; a stop valve 1 26 is provided on the inlet branch pipe 15 and is connected to the heat exchange unit 3; the stop valve 1 26 is used to adjust the pressure resistance of the inlet branch pipe 15 to ensure that the steam flow rate flowing in each inlet branch pipe is consistent; when the on-off valve 5 25 is opened, the heating inlet main pipe 14 and the inlet branch pipe 15 evenly pass the high-temperature steam into the heat exchange unit 3;

[0054] The outlet of the heat exchange unit 3 is provided with an outlet branch pipe 16, on which a stop valve 27 is provided and which is collected at the front end of the heating outlet main pipe 17; the heating outlet main pipe 17 is provided with an opening and closing valve 6 28, and is connected to the boiler heating pipeline or the auxiliary steam pipeline. When the opening and closing valve 6 28 is opened, the heating outlet main pipe 17 leads out the steam after heat exchange;

[0055] The inlet of the heating inlet main pipe 14 can be connected to a certain stage of the steam turbine extraction pipeline, or the main steam pipeline, or other steam heat sources. As long as the temperature of the heat source steam is higher than the set value of the heat storage medium, there is no requirement for the pressure of the heat source steam.

[0056] The water injection pipeline 10 is provided with an opening and closing valve 18; the energy release main pipe 11 is provided with an opening and closing valve 2 19 and a pressure reducing valve 20;

[0057] The heating inlet main pipe 14 is provided with an opening and closing valve 5 25; the heating outlet main pipe 17 is provided with an opening and closing valve 6 28;

[0058] The inlet branch pipe 15 is provided with a stop valve 1 26 , the outlet branch pipe 16 is provided with a stop valve 2 27 , and the mixing branch pipe 29 is provided with a stop valve 3 30 .

[0059] The housing 1 is also provided with a safety valve 5, a level gauge, a thermometer, a pressure gauge and other instruments. Example 2

[0060] like Figure 1 As shown, this embodiment provides an energy supply system for rapid load increase of a coal-fired power generation unit, comprising the aforementioned heat storage device, a water-cooled wall 8, a steam drum or a steam-water separator 9, an external steam-water separator 6, a water storage tank 7, an energy release branch 1 12 and an energy release branch 2 13;

[0061] The inlet end of the external steam-water separator 6 is connected to the heat storage device, and the first outlet end of the external steam-water separator 6 is connected to the outlet pipe of the steam drum or the steam-water separator 9 through the energy release branch 12; the second outlet end of the external steam-water separator 6 is connected to the lower end of the water-cooled wall 8 through the energy release branch 2 13; a water storage tank 7 is provided on the energy release branch 2 13, and the water storage tank 7 is used to store the saturated water separated by the external steam-water separator 6; the upper end of the water-cooled wall 8 is connected to the steam drum or the steam-water separator 9.

[0062] The energy release branch 12 is provided with an opening and closing valve 3 21 and a check valve 1 22; the energy release branch 2 13 is provided with an opening and closing valve 4 23 and a check valve 2 24; the energy release branch 12 is provided with an opening and closing valve 3 21 and a check valve 1 22, the inlet of the energy release branch 12 is connected to the steam outlet of the external steam-water separator 6, and its outlet is connected to the boiler superheated steam pipeline (coated superheater or low-temperature superheater), and the energy release branch 12 passes the separated dry steam into the boiler superheater for superheating when the opening and closing valve 3 21 is opened; the energy release branch 2 13 is provided with an opening and closing valve 4 23 and a check valve 2 24, the inlet of the energy release branch 2 13 is connected to the water storage tank 7, and its outlet is connected to the boiler downcomer or the water-cooled wall inlet header, and the energy release branch 2 13 passes the water in the water storage tank 7 into the boiler steam-water system when the opening and closing valve 4 23 is opened.

[0063] The flow rate of the working fluid releasing energy of the heat storage device is jointly controlled by the opening degree of the on-off valve three 21 of the energy release branch 12 and the opening degree of the on-off valve four 23 of the energy release branch 2 13.

[0064] This embodiment also includes an automatic control system, which is used to control the automatic operation of the energy supply system. Example 3

[0065] The present embodiment provides a method for rapidly increasing the load of a coal-fired power generation unit. When the coal-fired power generation unit is operating stably at medium load or high load or is operating at reduced load, surplus steam energy is stored in a heat storage device. When the unit is in a low load condition and needs to rapidly increase the load, the heat storage device directly supplies high enthalpy steam and saturated water to the boiler steam-water system, thereby directly and rapidly increasing the boiler steam yield and realizing rapid load increase of the coal-fired power generation unit.

[0066] The specific steps include:

[0067] (1) Fill with water

[0068] Open the on-off valve 18, close the stop valve 30, use the water injection pipeline 10 to fill a certain amount of boiler supercooled water into the heat storage device to the filling water level, close the on-off valve 18, and the water filling is completed;

[0069] (2) Charging

[0070] Open the opening and closing valve 5 25 and the opening and closing valve 6 28; open the stop valve 1 26 and the stop valve 2 27, and the high-temperature heating steam enters the heat exchange unit 3 along the heating inlet main pipe 14 through the inlet branch pipe 15, and transfers heat to the water in the device in the form of non-contact heat exchange; when the working medium temperature and pressure in the heat storage device rise to the set value, close the opening and closing valve 5 25 and the opening and closing valve 6 28, and the charging is completed;

[0071] (3) Insulation

[0072] After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is lower than the set pressure value by a certain value, which is set to 0.1MPa in this embodiment (generally set to 0.05MPa-0.25MPa), the opening and closing valve 5 25 and the opening and closing valve 6 28 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valve 5 25 and the opening and closing valve 6 28 are closed.

[0073] (4) Energy release

[0074] When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, the opening and closing valve 2 19, the opening and closing valve 3 21 and the opening and closing valve 4 23 are opened, and the steam in the gas collecting chamber 4 above the heat storage device enters the pressure reducing valve 20 along the energy release main pipe 11. The pressure reducing valve 20 reduces the pressure of the high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator 6 for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 12 to be superheated and directly produce steam. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall 8 along the energy release branch 2 13. By increasing the feed water enthalpy, the heat transfer temperature difference is reduced and the steam production rate is accelerated. Example 4

[0075] This embodiment provides an operation mode when the high temperature heating steam directly meets the steam quality requirements of the plenum chamber, specifically including the following steps:

[0076] (1) Charging

[0077] Close the opening and closing valve 18 and the opening and closing valve 6 28; close the stop valve 1 26 and the stop valve 2 27, open the opening and closing valve 5 25 and the stop valve 3 30, and the high-temperature heating steam directly enters the heat storage device along the heating inlet main pipe 14 through the mixing branch pipe 29. When the working medium temperature and pressure in the heat storage device reach the set value, close the opening and closing valve 5 25 and the stop valve 3 30, and the charging is completed;

[0078] (2) Insulation

[0079] After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is lower than the set pressure value by a certain value, which is set to 0.1MPa in this embodiment (generally set to 0.05MPa-0.25MPa), the opening and closing valve 5 25 and the stop valve 30 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valve 5 25 and the stop valve 30 are closed.

[0080] (3) Energy release

[0081] When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, the opening and closing valve 2 19, the opening and closing valve 3 21 and the opening and closing valve 4 23 are opened, and the steam in the gas collecting chamber 4 above the heat storage device enters the pressure reducing valve 20 along the energy release main pipe 11. The pressure reducing valve 20 reduces the pressure of the high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator 6 for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 12 to be superheated and directly produce steam. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall 8 along the energy release branch 2 13. By increasing the feed water enthalpy, the heat transfer temperature difference is reduced and the steam production rate is accelerated.

[0082] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for rapidly increasing the load of a coal-fired power generation unit, the method using an energy supply system, the energy supply system comprising a heat storage device; The heat storage device comprises a shell, a heat exchange unit is arranged inside the shell, and a circulation cover is arranged outside the heat exchange unit; a gas collecting chamber is arranged on the shell; The shell is connected to a water injection pipeline, and the gas collecting chamber is connected to an energy release main pipe; One end of the heat exchange unit is connected to the heating inlet main pipe through an inlet branch pipe, and the other end of the heat exchange unit is connected to the heating outlet main pipe through an outlet branch pipe; The heating inlet main pipe is also provided with a mixing branch pipe, and the mixing branch pipe is communicated with the interior of the shell; The circulation cover is arranged vertically, and the upper and lower ends of the circulation cover are arranged with openings; The water injection pipeline is provided with an opening and closing valve 1; the energy release main pipe is provided with an opening and closing valve 2 and a pressure reducing valve; The heating inlet main pipe is provided with an opening and closing valve five; the heating outlet main pipe is provided with an opening and closing valve six; The inlet branch pipe is provided with a first stop valve, the outlet branch pipe is provided with a second stop valve, and the mixing branch pipe is provided with a third stop valve; It also includes a water-cooled wall, a steam drum or a steam-water separator, an external steam-water separator, a water storage tank, an energy release branch 1 and an energy release branch 2; The inlet end of the external steam-water separator is connected to the heat storage device, and the first outlet end of the external steam-water separator is connected to the outlet pipe of the steam drum or the steam-water separator through the energy release branch 1; the second outlet end of the external steam-water separator is connected to the lower end of the water-cooled wall through the energy release branch 2; a water storage tank is provided on the energy release branch 2; the upper end of the water-cooled wall is connected to the steam drum or the steam-water separator; The energy release branch line 1 is provided with an opening and closing valve 3 and a check valve 1; the energy release branch line 2 is provided with an opening and closing valve 4 and a check valve 2; It also includes an automatic control system, which is used to control the automatic operation of the energy supply system; The method comprises the following steps: (1) Fill with water Open the first on-off valve, close the third stop valve, use the water injection pipeline to fill a certain amount of boiler supercooled water into the heat storage device to the filling water level, close the first on-off valve, and the water filling is completed; (2) Charging Open the opening and closing valve 5 and the opening and closing valve 6; open the stop valve 1 and the stop valve 2, and the high-temperature heating steam enters the heat exchange unit along the heating inlet main pipe through the inlet branch pipe, and transfers heat to the water in the device in the form of non-contact heat exchange; when the working medium temperature and pressure in the heat storage device rise to the set value, close the opening and closing valve 5 and the opening and closing valve 6, and the charging is completed; (3) Insulation After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is lower than the set pressure value by a certain value, the opening and closing valves 5 and 6 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valves 5 and 6 are closed. (4) Energy release When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, the opening and closing valve 2, the opening and closing valve 3 and the opening and closing valve 4 are opened, and the steam in the air collecting chamber above the heat storage device enters the pressure reducing valve along the energy release main pipe. The pressure reducing valve reduces the pressure of high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 1 for overheating and direct steam production. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall along the energy release branch 2, thereby reducing the heat transfer temperature difference and accelerating the steam production rate by increasing the feed water enthalpy value; When the high temperature heating steam directly meets the steam quality requirements of the plenum chamber, the method comprises the following steps: (1) Charging Close the opening and closing valve 1 and the opening and closing valve 6; close the stop valve 1 and the stop valve 2, open the opening and closing valve 5 and the stop valve 3, and the high-temperature heating steam directly enters the heat storage device along the heating inlet main pipe through the mixing branch pipe. When the working medium temperature and pressure in the heat storage device reach the set value, close the opening and closing valve 5 and the stop valve 3, and the charging is completed; (2) Insulation After the heat storage device is fully charged, it is in the heat preservation stage. The automatic control system monitors the pressure of the heat storage device online. When the pressure of the device is lower than the set pressure value by a certain value, the opening and closing valve 5 and the stop valve 3 are opened to introduce high-temperature steam for heating. When the pressure of the heat storage device reaches the set value again, the opening and closing valve 5 and the stop valve 3 are closed. (3) Energy release When the unit needs to change load quickly or start in cold or hot state urgently, the heat storage device is in the energy release stage, and the opening and closing valves 2, 3 and 4 are opened. The steam in the air collecting chamber above the heat storage device enters the pressure reducing valve along the energy release main pipe. The pressure reducing valve reduces the high-pressure steam by throttling to form a steam-water two-phase flow, and then enters the external steam-water separator for steam-water separation. The saturated steam formed by separation enters the superheater along the energy release branch 1 for superheating and direct steam production. The saturated water formed by separation passes through the water storage tank and enters the water-cooled wall along the energy release branch 2. By increasing the feed water enthalpy, the heat transfer temperature difference is reduced and the steam production rate is accelerated.

2. The method according to claim 1, characterized in that The housing is also provided with a safety valve and / or a liquid level meter and / or a thermometer and / or a pressure gauge.

3. The method according to claim 1, characterized in that The flow rate of the working fluid for releasing energy of the heat storage device is jointly controlled by the opening degree of the on-off valve three of the energy release branch one and the opening degree of the on-off valve four of the energy release branch two.

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