Efficient peak regulation and heat storage power generation system for thermal power generation

Abstract

The utility model relates to a thermal power generation efficient peak regulation heat storage power generation system which comprises a boiler, a steam turbine, a condenser, a heater and a heat storage system. The ejector comprises a reducing pipe, a steam chamber and an increasing pipe, the reducing pipe is used for receiving extracted steam in the middle of the steam turbine, the steam chamber is used for mixing the extracted steam received by the reducing pipe and dead steam of the steam turbine, and the increasing pipe is used for increasing the pressure of the mixed steam; a cold water tank; a hot water tank. According to the efficient peak-shaving heat-storage power generation system for thermal power generation, through accurate adjustment of the back pressure adjusting device and the ejector, the heat energy utilization efficiency of dead steam is improved, heat originally lost at the cold end is reduced, the overall efficiency of the thermal power generation system is greatly improved through effective recovery and utilization of the heat, and the energy consumption of the thermal power generation system is reduced. And optimal configuration and efficient conversion of energy are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal power generation heat storage and peak regulation, in particular to a high-efficiency peak regulation heat storage power generation system for thermal power generation. Background Art

[0002] In existing technologies, while thermal power plants provide a stable power supply, they also have problems such as low efficiency, limited peak-shaving capacity and environmental pollution. How to improve the flexibility and efficiency of thermal power plants and reduce carbon emissions has become a technical problem that the power industry urgently needs to solve.

[0003] At present, thermal power plants mainly achieve peak load regulation by adjusting boiler load, but this method is limited by the minimum stable combustion load, resulting in limited peak load regulation capacity. In addition, thermal power plants have a variety of energy storage methods (such as electric energy storage, hot water energy storage), and molten salt energy storage is popular due to its large capacity, long cycle, wide temperature range, and low cost. However, molten salt itself has high cost, is a hazardous chemical during transportation and storage, and is highly dangerous. Moreover, due to its own physical and chemical properties, the system needs to operate safely and stably, and the system is complex and has many types of equipment.

[0004] In addition, during the thermal power generation process, the cold end loss in the condenser or air cooler can reach 50% to 60%. This loss not only reduces the power generation efficiency, but also causes energy waste. Utility Model Content

[0005] In order to solve the above problems, the utility model provides a high-efficiency peak-shaving heat storage power generation system which reduces the heat loss at the cold end and improves the overall efficiency of the thermal power generation system.

[0006] In order to achieve the above-mentioned purpose, the high-efficiency peak-shaving heat storage power generation system designed by the utility model for thermal power generation comprises:

[0007] boilers, for generating steam;

[0008] a steam turbine connected to the boiler to generate electricity by using steam to generate work;

[0009] A condenser connected to the steam turbine and used to cool the exhaust steam of the steam turbine and form condensed water;

[0010] A heater connected to the condenser and used for heating condensed water of the condenser;

[0011] Thermal storage systems, used to store and release thermal energy, include:

[0012] a back pressure regulating device connected to the condenser and used for regulating the back pressure in the condenser;

[0013] The ejector comprises a reducer, a steam chamber and a diffuser, wherein the reducer is used to receive the extraction steam from the middle of the steam turbine, the steam chamber is used to mix the extraction steam received by the reducer with the exhaust steam of the steam turbine, and the diffuser is used to increase the pressure of the mixed steam;

[0014] Cold water tank, used to store cold water;

[0015] The hot water tank is connected to the heater and the cold water tank and is used to heat the cold water to form high-temperature saturated water through the mixed steam from the gradually expanding tube.

[0016] In order to improve the transfer efficiency of heat energy in the hot water tank, a thermal deaerator for removing non-condensable gases is provided in the hot water tank.

[0017] In order to maintain the pressure in the hot water tank, the ejector also has a flow regulating valve, which is used to adjust the flow of the mixed steam in the ejector.

[0018] In order to maintain the water level of the condenser unchanged, a pipeline connecting the cold water tank to the hot water tank is branched off and connected to the condenser.

[0019] In order to balance the amount of hot water output when the hot water tank releases heat, the condensed water formed by the condenser is divided into two paths, one is discharged into the cold water tank through a pipeline, and the other is injected into the boiler after passing through the heater.

[0020] In order to further improve the overall thermal efficiency of the peak heater, a path of the mixed steam output from the gradually expanding tube is connected to the heat source input end of the heater through a pipeline, and a shut-off valve is arranged on the pipeline.

[0021] In order to reduce energy loss, the steam turbine comprises a steam turbine high-pressure cylinder and a steam turbine low-pressure cylinder, and a reducer is connected to the middle of the steam turbine low-pressure cylinder to introduce extraction steam.

[0022] Preferably, the back pressure regulating device is any one of a water ring vacuum pump, a water jet vacuum pump, and a steam jet vacuum pump.

[0023] The high-efficiency peak-shaving heat storage power generation system for thermal power generation designed by the utility model improves the thermal energy utilization efficiency of exhaust steam and reduces the heat originally lost at the cold end through precise back pressure regulation device and ejector regulation. The effective recovery and utilization of this heat greatly improves the overall efficiency of the thermal power generation system and realizes the optimal configuration and efficient conversion of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a system provided in an embodiment of the present application;

[0025] Figure 2 It is the structure and pressure curve diagram of the ejector according to the embodiment of the present application.

[0026] Among them: boiler 10, steam turbine 20, steam turbine high-pressure cylinder 21, steam turbine low-pressure cylinder 22, condenser 30, heater 40, heat storage system 50, back pressure regulating device 51, ejector 52, convergent pipe 521, steam chamber 522, divergent pipe 523, cold water tank 53, hot water tank 54, thermal deaerator 60, flow regulating valve 70. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0028] Example 1.

[0029] like Figure 1 As shown, the high-efficiency peak-shaving heat storage power generation system for thermal power generation described in this embodiment includes:

[0030] A boiler 10 for generating steam;

[0031] A steam turbine 20, connected to the boiler 10, generates electricity by using steam to generate work;

[0032] A condenser 30, connected to the steam turbine 20, for cooling the exhaust steam of the steam turbine 20 and forming condensed water;

[0033] A heater 40 connected to the condenser 30 and used for heating condensed water of the condenser 30;

[0034] The heat storage system 50 is used to store and release thermal energy, including:

[0035] A back pressure regulating device 51, connected to the condenser 30, for regulating the back pressure in the condenser 30;

[0036] The ejector 52 includes a convergent pipe 521, a steam chamber 522 and a divergent pipe 523. The convergent pipe 521 is used to receive the extraction steam from the middle of the steam turbine 20. The steam chamber 522 is used to mix the extraction steam received by the convergent pipe 521 with the exhaust steam of the steam turbine 20. The divergent pipe 523 is used to increase the pressure of the mixed steam.

[0037] A cold water tank 53, used for storing cold water;

[0038] The hot water tank 54 is connected to the heater 40 and the cold water tank 53, and is used to heat the cold water through the mixed steam from the gradually expanding pipe 523 to form high-temperature saturated water.

[0039] When working, Figure 1As shown, when the system is started, the boiler 10 heats the water source to generate steam, and the steam is transported to the turbine 20 through a pipeline to drive the turbine to do work, converting thermal energy into mechanical energy, and then converting it into electrical energy through a generator. Then, the exhaust steam generated by the operation of the turbine 20 is guided to the condenser 30, where the steam is cooled and condensed into water. At the same time, the back pressure in the condenser 30 is adjusted by the back pressure regulating device 51 to optimize the heat energy conversion efficiency. Subsequently, the condensed water flows out of the condenser 30 and enters the heater 40 for heating. The heated hot water returns to the boiler 10 and is converted into steam again.

[0040] The heat storage system 50 is used to store heat energy during peak power generation and release the stored heat energy during the period when the grid needs to fill the valley. Specifically:

[0041] During the peak shaving period of thermal power generation, the back pressure in the condenser 30 is adjusted to 0.02MPa by adjusting the back pressure regulating device 51, and at the same time, a path of extraction steam (generally 2.5Mpa.a) is extracted from the cylinder of the steam turbine 20 as power steam, and a path of exhaust steam from the steam turbine 20 is separated to connect the power steam and enter the ejector. At this time, the temperature of the condensed water in the condenser 30 is 60°C. In this embodiment, the back pressure regulating device 51 is any one of a water ring vacuum pump, a water ejector, and a steam ejector.

[0042] In the ejector 52, refer to Figure 2 As shown, the motive steam passes through the convergent tube 521, and the flow velocity becomes faster. According to the Bernoulli principle, as the flow velocity becomes faster, the motive steam pressure becomes larger. In the steam chamber 522, the motive steam pressure is reduced to P1, and its pressure is less than the exhaust steam pressure P0, that is, the low-pressure exhaust steam enters the steam chamber 522 and mixes with the motive steam in the steam chamber 522. The mixed steam enters the second half (the expanding section 523) of the ejector 52. The flow velocity of the mixed steam gradually decreases in the expanding section 523. According to the Bernoulli principle, the pressure of the mixed steam increases when it flows through the expanding section 523, and its pressure is increased to the pressure P3 required in the system; at this time, another part of the exhaust steam of the steam turbine 20 enters the condenser 30 (or air cooler) to exchange heat with the circulating water, and condensed water is formed through the condenser 30. Because the specific volume of steam condenses into water is sharply reduced, the back pressure of the steam turbine 20 is maintained at P0.

[0043] In this way, the exhaust steam of the turbine 20 can be smoothly guided around the condenser 30 by the ejector 52, that is, the heat of this part of the steam will not form a cold end loss, and at the same time the exhaust steam pressure can be increased from P0 to the mixed steam P3. Subsequently, the cold water in the cold water tank 53 (water temperature 25-40°C) is pumped into the hot water tank 54 through the cold water pump, and the mixed steam with the pressure increased by the ejector 52 enters the hot water tank 54, and the cold water (condensed water) is heated in the hot water tank 54 to form saturated water in the mixed water in the hot water tank 54. At the same time, the pressure p3' in the hot water tank 54 is maintained. At this time, the water temperature in the hot water tank 54 reaches 130-140°C, achieving the purpose of heat storage. In the above heat storage process, since the back pressure of the steam turbine 20 is set to 0.02Mpa.a, the exhaust enthalpy to the condenser 30 is increased, and low-pressure steam is extracted from the middle of the steam turbine 20. This part of the low-pressure steam does not do work in the steam turbine 20. Even if the work done by the steam turbine 20 is reduced, the power generation is reduced relative to the minimum stable combustion load of the boiler 10 (30% of the rated boiler evaporation capacity), thereby playing a low power grid peak shaving function.

[0044] During the grid valley filling period, the back pressure of the steam turbine 20 is reduced to 0.005 MPa.a through the back pressure regulating device 51. At this time, the temperature formed in the condenser 30 is 33°C. Compared with the aforementioned grid peak shaving stage, the reduction in exhaust pressure and condensate temperature increases the steam work power in the steam turbine 20, thereby improving the power generation efficiency of the entire steam turbine 20. At this time, the boiler 10 and the steam turbine 20 are operated at full load or even overload (105% to 110%).

[0045] At this time, a heat storage system 50 is needed to release heat: the hot water (130-140°C) in the hot water tank 54 is pressurized by a hot water pump and enters the heater 40 (deaerator) for thermal power generation. At the same time, the steam turbine 20 is over-generated (for example, over-generated by 110%), thus realizing the valley filling function of the power grid.

[0046] In some embodiments, Figure 1 As shown, in order to improve the transfer efficiency of heat energy in the hot water tank 54, a thermal deaerator 60 for removing non-condensable gases is provided in the hot water tank 54. In actual implementation, non-condensable gases (such as oxygen, nitrogen, etc.) will hinder the heat transfer between hot water and steam. By removing non-condensable gases through the thermal deaerator 60, the heat transfer efficiency in the hot water tank 54 can be improved, ensuring that heat energy is effectively transferred to water, thereby improving the purity and quality of stored hot water.

[0047] In some embodiments, Figure 1As shown, in order to maintain the pressure in the hot water tank 54, the ejector 52 also has a flow regulating valve 70, which is used to adjust the flow of the mixed steam in the ejector 52. In this way, the flow regulating valve 70 can adjust the flow of the mixed steam passing through the ejector 52, thereby accurately controlling the amount of steam entering the hot water tank 54, which helps to maintain the pressure in the hot water tank 54 stable, ensuring that the system operates at the optimal pressure (p3'), so as to reduce energy waste and improve the overall system efficiency.

[0048] In some embodiments, Figure 1 As shown, in order to maintain the water level of the condenser 30 unchanged, a pipeline from the cold water tank 53 to the hot water tank 54 is branched and connected to the condenser 30. During operation, as the steam-water content of the system decreases due to continuous steam extraction from the steam turbine 20, a path of cold water is extracted from the cold water tank 53 and enters the condenser 30, which can maintain the water level of the condenser 30 unchanged, prevent the condenser 30 from overheating and damage, and thus extend the service life of the equipment.

[0049] In some embodiments, Figure 1 As shown, in order to balance the amount of hot water output by the hot water tank 54 when releasing heat, the condensed water formed by the condenser 30 is divided into two paths, one of which is discharged into the cold water tank 53 through a pipeline, and the other is injected into the boiler 10 after passing through the heater 40. With this structural design, the dynamic balance of the water volume in the system can be ensured, which not only reduces the demand for external cooling water, but also reduces the operating cost and environmental impact of the system.

[0050] In some embodiments, Figure 1 As shown, the mixed steam output from the gradually expanding pipe 523 is separated into one path and connected to the heat source input end 41 of the heater 40 through a pipeline, and a shut-off valve is arranged on the pipeline. In this way, during the valley filling period of the power grid, the steam after the ejector 52 is discharged into the heat source input end 41 of the heater 40 as the heating steam source for condensed water, which can make full use of the waste heat in the steam, reduce fuel consumption, and improve the overall thermal efficiency of the system.

[0051] In some embodiments, Figure 1 As shown, the steam turbine 20 includes a steam turbine high-pressure cylinder 21 and a steam turbine low-pressure cylinder 22, and a reducer 521 is connected to the middle of the steam turbine low-pressure cylinder 22 to introduce extraction steam. The steam temperature in the steam turbine low-pressure cylinder 22 is relatively low, and extracting steam from the middle of the low-pressure cylinder can reduce heat loss, so that more heat energy can be effectively utilized, thereby improving the overall thermal efficiency of the system.

[0052] The efficient peak-shaving heat storage power generation system for thermal power generation provided in this embodiment improves the thermal energy utilization efficiency of exhaust steam and reduces the heat originally lost at the cold end through precise back pressure regulation device and ejector regulation. The effective recovery and utilization of this heat greatly improves the overall efficiency of the thermal power generation system and realizes the optimal configuration and efficient conversion of energy.

[0053] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 on the present invention.

[0054] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A high-efficiency peak-shaving heat storage power generation system for thermal power generation, characterized in that: include: boilers, for generating steam; a steam turbine connected to the boiler to generate electricity by using steam to generate work; A condenser connected to the steam turbine and used to cool the exhaust steam of the steam turbine and form condensed water; A heater connected to the condenser and used for heating condensed water of the condenser; Thermal storage systems, used to store and release thermal energy, include: a back pressure regulating device connected to the condenser and used for regulating the back pressure in the condenser; The ejector comprises a reducer, a steam chamber and a diffuser, wherein the reducer is used to receive the extraction steam from the middle of the steam turbine, the steam chamber is used to mix the extraction steam received by the reducer with the exhaust steam of the steam turbine, and the diffuser is used to increase the pressure of the mixed steam; Cold water tank, used to store cold water; The hot water tank is connected to the heater and the cold water tank and is used to heat the cold water to form high-temperature saturated water through the mixed steam from the gradually expanding tube.

2. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 1 is characterized in that: A thermal deaerator for removing non-condensable gases is arranged in the hot water tank.

3. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 1, characterized in that: The ejector also has a flow regulating valve, which is used to regulate the flow of the mixed steam in the ejector.

4. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 1 is characterized in that: A pipeline connecting the cold water tank to the hot water tank is branched off and connected to the condenser.

5. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 1, characterized in that: The condensate formed in the condenser is divided into two paths, one path is discharged into the cold water tank through a pipeline, and the other path is injected into the boiler after passing through the heater.

6. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 5, characterized in that: A path of the mixed steam outputted from the gradually expanding tube is connected to the heat source input end of the heater through a pipeline, and a shut-off valve is arranged on the pipeline.

7. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to any one of claims 1 to 6, characterized in that: The steam turbine comprises a steam turbine high-pressure cylinder and a steam turbine low-pressure cylinder, and a reducer is connected to the middle of the steam turbine low-pressure cylinder to introduce extraction steam.

8. The high-efficiency peak-shaving heat storage power generation system for thermal power generation according to claim 1, characterized in that: The back pressure regulating device is any one of a water ring vacuum pump, a water jet vacuum pump, and a steam jet vacuum pump.

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