An efficient deep peak shaving system and method for thermal power plants

Abstract

The present invention discloses an efficient deep peak shaving system and method for a thermal power plant. The outlet of the #1 boiler is communicated with the inlet of the #1 steam turbine and the inlet of the high-temperature and high-pressure steam header. The outlet of the #2 boiler is communicated with the inlet of the high-temperature and high-pressure steam header and the inlet of the #2 steam turbine. The outlet of the high-temperature and high-pressure steam header is communicated with the inlets of the #1 steam turbine and the #2 steam turbine. The outlets of the #1 steam turbine and the #2 steam turbine are communicated with the heat release side of the steam heat storage hot water tank. The outlet of the heat network return water circulation pump is communicated with the heat absorption side inlet of the steam heat storage hot water tank. The inlet of the heat network supply water circulation pump is communicated with the heat absorption side outlet of the steam heat storage hot water tank. The #1 steam turbine is connected to the #1 generator, and the #2 steam turbine is connected to the #2 generator. This system and method can achieve flexible deep peak shaving for multiple units in a thermal power plant, and the system is simple, with low investment cost and large benefits.

Description

Technical Field

[0001] The invention belongs to the field of deep peak shaving of thermal power plants, and relates to an efficient deep peak shaving system and method for thermal power plants. Background Art

[0002] With the changes in the national power policies in recent years, the main functions of thermal power plants have also changed simultaneously. They have changed from the main power supply to participating in and cooperating with the power grid for deep peak shaving. At the same time, the state has introduced a deep peak shaving electricity price subsidy policy, which greatly stimulates the enthusiasm of thermal power plants for unit deep peak shaving transformation. Currently, thermal power faces the risk of structural overcapacity, and new energy faces great pressure for consumption. Thermal power is bound to make way for the development of new energy. Thermal power units are facing deep peak shaving. For the "Three-North" regions, the contradiction between thermal power and wind power during the heating period is particularly prominent. The best period for wind resources is during the winter heating period. In addition, the proportion of thermal power units in some provinces and regions is too high, and other types of peak shaving power sources are relatively scarce. The growing heating demand and the continuous increase in the installed capacity of clean energy have resulted in a very limited peak shaving space. Especially in the Northeast region, most of the thermal power is cogeneration units, and the peak shaving capacity is only 10%, which affects the consumption of existing new energy and the development of new energy increment. The hard gap in peak shaving capacity causes serious curtailment of new energy in some regions, resulting in the fact that thermal power units can only achieve deep peak shaving through transformation.

[0003] At present, the units participating in deep peak shaving operate deviating from the design value for a long time, resulting in a decline in the safety and economy of the units. From the technologies adopted and the practice of transformation, the transformed units have problems such as the safety of boiler low-load stable combustion and water circulation, the full-load input of the denitration device and the low-load cooling of the steam turbine, the flexibility of the control system during long-term low-load and rapid load change, the problems of equipment operation cycle and life attenuation, and the thermal-electric decoupling of heating units to varying degrees, all of which need to be further studied and optimized. It is necessary to design a new type of efficient deep peak shaving system and method for thermal power plants with advantages such as simple system, small investment, and large benefits to achieve unit deep peak shaving. Summary of the Invention

[0004] The purpose of the invention is to overcome the above-mentioned disadvantages of the prior art, and provides an efficient deep peak shaving system and method for thermal power plants, which can realize flexible deep peak shaving of multiple units in a thermal power plant, and has the advantages of simple system, low investment cost, and large benefits.

[0005] To achieve the above purpose, the efficient deep peak shaving system for thermal power plants described in the invention includes #1 boiler, #1 steam turbine, high-temperature and high-pressure steam header, #2 boiler, #2 steam turbine, steam heat storage hot water tank, heat network return water circulation pump, and heat network supply water circulation pump;

[0006] The outlet of Boiler #1 is connected to the inlet of Steam Turbine #1 and the inlet of the high-temperature and high-pressure steam header. The outlet of Boiler #2 is connected to the inlet of the high-temperature and high-pressure steam header and the inlet of Steam Turbine #2. The outlet of the high-temperature and high-pressure steam header is connected to the inlets of Steam Turbine #1 and Steam Turbine #2. The outlets of Steam Turbine #1 and Steam Turbine #2 are connected to the heat release side of the steam storage hot water tank. The outlet of the heat network return water circulation pump is connected to the inlet of the heat absorption side of the steam storage hot water tank. The inlet of the heat network supply water circulation pump is connected to the outlet of the heat absorption side of the steam storage hot water tank;

[0007] Steam Turbine #1 is connected to Generator #1, and Steam Turbine #2 is connected to Generator #2.

[0008] The outlet of Boiler #1 is connected to the inlet of Steam Turbine #1 via the first regulating valve, and the outlet of Boiler #1 is connected to the inlet of the high-temperature and high-pressure steam header via the second regulating valve. The outlet of the high-temperature and high-pressure steam header is connected to the inlet of Steam Turbine #1 via the third regulating valve.

[0009] The outlet of Boiler #2 is connected to the inlet of Steam Turbine #2 via the fourth regulating valve, and the outlet of Boiler #2 is connected to the inlet of the high-temperature and high-pressure steam header via the fifth regulating valve. The outlet of the high-temperature and high-pressure steam header is connected to the inlet of Steam Turbine #2 via the sixth regulating valve.

[0010] The outlet of Steam Turbine #1 is connected to the inlet of the heat release side of the steam storage hot water tank via the #1 extraction regulating valve.

[0011] The outlet of Steam Turbine #2 is connected to the inlet of the heat release side of the steam storage hot water tank via the #2 extraction regulating valve.

[0012] The lower layer area and the upper layer area on the heat absorption side of the steam storage hot water tank are connected via a self-circulation pump.

[0013] The efficient peak shaving method for a thermal power plant according to the present invention includes the following steps:

[0014] Under normal circumstances, connect Boiler #1 to Steam Turbine #1, disconnect the connection between Boiler #1 and the high-temperature and high-pressure steam header, connect Boiler #2 to Steam Turbine #2, disconnect the connection between Boiler #2 and the high-temperature and high-pressure steam header, and at the same time disconnect the #1 extraction regulating valve and the #2 extraction regulating valve. Generator #1 and Generator #2 operate independently for power generation;

[0015] When the power generation is excessive, the unit needs to perform deep peak shaving. When the #1 boiler starts, open the second regulating valve, the fourth regulating valve, the fifth regulating valve, and the sixth regulating valve. Introduce the excess high-temperature and high-pressure steam of the #1 boiler into the high-temperature and high-pressure steam header through the second regulating valve, and then distribute it to the #2 steam turbine through the sixth regulating valve, so that the #2 generator generates electricity. Among them, the #2 boiler does not need to start. When the #2 boiler starts, close the fourth regulating valve and the sixth regulating valve, open the first regulating valve, the second regulating valve, the third regulating valve, and the fifth regulating valve. Introduce the excess high-temperature and high-pressure steam of the #2 boiler into the high-temperature and high-pressure steam header through the fifth regulating valve, and then distribute it to the #1 steam turbine through the third regulating valve, so that the #1 generator generates electricity. Among them, the #1 boiler does not need to start. When there is a heat load demand at this time, open the #1 extraction regulating valve and the #2 extraction regulating valve, connect the steam heat storage hot water tank with the #1 steam turbine and the #2 steam turbine, and extract the excess heat from the #1 steam turbine and the #2 steam turbine and store it in the steam heat storage hot water tank.

[0016] When the power generation demand of the winter cogeneration unit is large, start the #1 boiler and the #2 boiler, close the second regulating valve, the third regulating valve, the fifth regulating valve, the sixth regulating valve, the #1 extraction regulating valve, and the #2 extraction regulating valve, and generate electricity at a high load separately through the #1 generator and the #2 generator. The heat required for heating is supplied from the steam heat storage hot water tank to reduce extraction.

[0017] During heating, the return water of the heat network is sent to the lower layer area of the heat absorption side of the steam heat storage hot water tank through the heat network return water circulation pump, and then sent to the upper layer area of the heat absorption side of the steam heat storage hot water tank through the self-circulation pump to exchange heat with the extraction steam of the steam turbine in the heat release side of the steam heat storage hot water tank to heat the heat network water, and then sent to the primary heat network through the heat network supply water circulation pump to supply heat to users.

[0018] The present invention has the following beneficial effects:

[0019] When the efficient deep peak shaving system and method of the present invention are specifically operated, when deep peak shaving is required, the excess high-temperature and high-pressure steam of the current boiler is input into the high-temperature and high-pressure steam header, and then the high-temperature and high-pressure steam in the high-temperature and high-pressure steam header is input into the steam turbine corresponding to another boiler. At the same time, the excess steam of the steam turbine can be discharged into the steam heat storage hot water tank, and deep peak shaving is carried out through the steam heat storage hot water tank and the high-temperature and high-pressure steam header. The system is simple, the investment cost is low, and the benefit is large. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the present invention.

[0021] Among them, 1 is the #1 boiler, 2 is the #2 boiler, 3 is the #1 steam turbine, 4 is the #2 steam turbine, 5 is the #1 generator, 6 is the #2 generator, 7 is the high-temperature and high-pressure steam header, 8 is the steam heat storage hot water tank, 9 is the first regulating valve, 10 is the second regulating valve, 11 is the third regulating valve, 12 is the fourth regulating valve, 13 is the fifth regulating valve, 14 is the sixth regulating valve, 15 is the #1 extraction regulating valve, 16 is the #2 extraction regulating valve, 17 is the heat network return water circulation pump, 18 is the self-circulation pump, and 19 is the heat network supply water circulation pump. Detailed implementation mode

[0022] The following further describes the present invention in detail with reference to the accompanying drawings:

[0023] Refer to Figure 1 The high-efficiency peak shaving system for a thermal power plant described in the present invention includes the #1 boiler 1, the #1 steam turbine 3, the high-temperature and high-pressure steam header 7, the #2 boiler 2, the #2 steam turbine 4, the steam heat storage hot water tank 8, the heat network return water circulation pump 17 and the heat network supply water circulation pump 19; the outlet of the #1 boiler 1 is connected to the inlet of the #1 steam turbine 3 and the inlet of the high-temperature and high-pressure steam header 7, the outlet of the #2 boiler 2 is connected to the inlet of the high-temperature and high-pressure steam header 7 and the inlet of the #2 steam turbine 4, the outlet of the high-temperature and high-pressure steam header 7 is connected to the inlet of the #1 steam turbine 3 and the inlet of the #2 steam turbine 4, the outlets of the #1 steam turbine 3 and the #2 steam turbine 4 are connected to the heat release side of the steam heat storage hot water tank 8, the outlet of the heat network return water circulation pump 17 is connected to the inlet of the heat absorption side of the steam heat storage hot water tank 8, and the inlet of the heat network supply water circulation pump 19 is connected to the outlet of the heat absorption side of the steam heat storage hot water tank 8; the #1 steam turbine 3 is connected to the #1 generator 5, and the #2 steam turbine 4 is connected to the #2 generator 6.

[0024] The outlet of the #1 boiler 1 is connected to the inlet of the #1 steam turbine 3 through the first regulating valve 9, the outlet of the #1 boiler 1 is connected to the inlet of the high-temperature and high-pressure steam header 7 through the second regulating valve 10, and the outlet of the high-temperature and high-pressure steam header 7 is connected to the inlet of the #1 steam turbine 3 through the third regulating valve 11; the outlet of the #2 boiler 2 is connected to the inlet of the #2 steam turbine 4 through the fourth regulating valve 12, the outlet of the #2 boiler 2 is connected to the inlet of the high-temperature and high-pressure steam header 7 through the fifth regulating valve 13, and the outlet of the high-temperature and high-pressure steam header 7 is connected to the inlet of the #2 steam turbine 4 through the sixth regulating valve 14.

[0025] The outlet of the #1 steam turbine 3 is connected to the inlet of the heat release side of the steam heat storage hot water tank 8 through the #1 extraction regulating valve 15; the outlet of the #2 steam turbine 4 is connected to the inlet of the heat release side of the steam heat storage hot water tank 8 through the #2 extraction regulating valve 16; the lower layer area and the upper layer area of the heat absorption side of the steam heat storage hot water tank 8 are connected through the self-circulation pump 18.

[0026] The high-efficiency peak shaving method for a thermal power plant described in the present invention includes the following steps:

[0027] Under normal circumstances, connect Boiler #1 with Steam Turbine #1, disconnect the connection between Boiler #1 and the high-temperature and high-pressure steam header 7, connect Boiler #2 with Steam Turbine #2, disconnect the connection between Boiler #2 and the high-temperature and high-pressure steam header 7, and at the same time disconnect the #1 extraction control valve 15 and the #2 extraction control valve 16. Generator #1 and Generator #2 operate independently for power generation.

[0028] When the power generation is in excess and the unit needs to perform deep peak shaving, when Boiler #1 starts, open the second control valve 10, the fourth control valve 12, the fifth control valve 13, and the sixth control valve 14. Introduce the excess high-temperature and high-pressure steam from Boiler #1 into the high-temperature and high-pressure steam header 7 through the second control valve 10, and then distribute it to Steam Turbine #2 through the sixth control valve 14, enabling Generator #2 to generate electricity. Among them, Boiler #2 does not need to start. When Boiler #2 starts, close the fourth control valve 12 and the sixth control valve 14, open the first control valve 9, the second control valve 10, the third control valve 11, and the fifth control valve 13. Introduce the excess high-temperature and high-pressure steam from Boiler #2 into the high-temperature and high-pressure steam header 7 through the fifth control valve 11, and then distribute it to Steam Turbine #1 through the third control valve 11, enabling Generator #1 to generate electricity. Among them, Boiler #1 does not need to start. When there is a heat load demand at this time, open the #1 extraction control valve 15 and the #2 extraction control valve 16, connect the steam storage hot water tank 8 with Steam Turbine #1 and Steam Turbine #2, and extract the excess heat from Steam Turbine #1 and Steam Turbine #2 and store it in the steam storage hot water tank 8.

[0029] When the power generation demand of the winter combined heat and power unit is large, start Boiler #1 and Boiler #2, close the second control valve 10, the third control valve 11, the fifth control valve 13, the sixth control valve 14, the #1 extraction control valve 15, and the #2 extraction control valve 16, and perform independent high-load power generation through Generator #1 and Generator #2. The heat required for heating is supplied from the steam storage hot water tank 8 to reduce extraction.

[0030] During heating, the return water of the heat network is sent to the lower layer area of the heat absorption side of the steam storage hot water tank 8 through the heat network return water circulation pump 17, and then sent to the upper layer area of the heat absorption side of the steam storage hot water tank 8 through the self-circulation pump 18 to exchange heat with the extraction steam (200 - 250°C) of the steam turbine in the heat release side of the steam storage hot water tank 8, heating the heat network water to 95°C, and then sending it into the primary heat network through the heat network supply water circulation pump 19 to supply heat to users.

Claims

1. An efficient deep peak shaving method for thermal power plants, characterized in that, Based on an efficient deep peak shaving system for thermal power plants, the efficient deep peak shaving system for thermal power plants includes Boiler #1 (1), Steam Turbine #1 (3), high-temperature and high-pressure steam header (7), Boiler #2 (2), Steam Turbine #2 (4), steam energy storage hot water tank (8), heat network return water circulation pump (17) and heat network supply water circulation pump (19); The outlet of Boiler #1 (1) is connected to the inlet of Steam Turbine #1 (3) and the inlet of the high-temperature and high-pressure steam header (7). The outlet of Boiler #2 (2) is connected to the inlet of the high-temperature and high-pressure steam header (7) and the inlet of Steam Turbine #2 (4). The outlet of the high-temperature and high-pressure steam header (7) is connected to the inlet of Steam Turbine #1 (3) and the inlet of Steam Turbine #2 (4). The outlets of Steam Turbine #1 (3) and Steam Turbine #2 (4) are connected to the heat release side of the steam energy storage hot water tank (8). The outlet of the heat network return water circulation pump (17) is connected to the inlet of the heat absorption side of the steam energy storage hot water tank (8). The inlet of the heat network supply water circulation pump (19) is connected to the outlet of the heat absorption side of the steam energy storage hot water tank (8); Steam Turbine #1 (3) is connected to Generator #1 (5), and Steam Turbine #2 (4) is connected to Generator #2 (6); The outlet of Boiler #1 (1) is connected to the inlet of Steam Turbine #1 (3) via the first regulating valve (9). The outlet of Boiler #1 (1) is connected to the inlet of the high-temperature and high-pressure steam header (7) via the second regulating valve (10). The outlet of the high-temperature and high-pressure steam header (7) is connected to the inlet of Steam Turbine #1 (3) via the third regulating valve (11); The outlet of Boiler #2 (2) is connected to the inlet of Steam Turbine #2 (4) via the fourth regulating valve (12). The outlet of Boiler #2 (2) is connected to the inlet of the high-temperature and high-pressure steam header (7) via the fifth regulating valve (13). The outlet of the high-temperature and high-pressure steam header (7) is connected to the inlet of Steam Turbine #2 (4) via the sixth regulating valve (14); The outlet of Steam Turbine #1 (3) is connected to the inlet of the heat release side of the steam energy storage hot water tank (8) via the #1 extraction regulating valve (15); The outlet of Steam Turbine #2 (4) is connected to the inlet of the heat release side of the steam energy storage hot water tank (8) via the #2 extraction regulating valve (16); The lower layer area and the upper layer area of the heat absorption side of the steam energy storage hot water tank (8) are connected via a self-circulation pump (18); It includes the following steps: Under normal conditions, connect Boiler #1 (1) to Steam Turbine #1 (3), disconnect the connection between Boiler #1 (1) and the high-temperature and high-pressure steam header (7), connect Boiler #2 (2) to Steam Turbine #2 (4), disconnect the connection between Boiler #2 (2) and the high-temperature and high-pressure steam header (7), and at the same time disconnect the #1 extraction regulating valve (15) and the #2 extraction regulating valve (16). Generator #1 (5) and Generator #2 (6) operate independently for power generation; When the power generation is excessive, the unit needs to perform deep peak shaving. When the #1 boiler (1) starts, open the second regulating valve (10), the fourth regulating valve (12), the fifth regulating valve (13), and the sixth regulating valve (14), and introduce the excess high-temperature and high-pressure steam of the #1 boiler (1) into the high-temperature and high-pressure steam header (7) through the second regulating valve (10), and then distribute it to the #2 steam turbine (4) through the sixth regulating valve (14), so that the #2 generator (6) generates electricity. Among them, the #2 boiler (2) does not need to start; when the #2 boiler (2) starts, close the fourth regulating valve (12) and the sixth regulating valve (14), and open the first regulating valve (9), the second regulating valve (10), the third regulating valve (11), and the fifth regulating valve (13), and introduce the excess high-temperature and high-pressure steam of the #2 boiler (2) into the high-temperature and high-pressure steam header (7) through the fifth regulating valve (13), and then distribute it to the #1 steam turbine (3) through the third regulating valve (11), so that the #1 generator (5) generates electricity. Among them, the #1 boiler (1) does not need to start; when there is a heat load demand at this time, open the #1 extraction regulating valve (15) and the #2 extraction regulating valve (16), connect the steam heat storage hot water tank (8) with the #1 steam turbine (3) and the #2 steam turbine (4), and extract the excess heat from the #1 steam turbine (3) and the #2 steam turbine (4) and store it in the steam heat storage hot water tank (8); When the power generation demand of the winter combined heat and power unit is large, start the #1 boiler (1) and the #2 boiler (2), close the second regulating valve (10), the third regulating valve (11), the fifth regulating valve (13), the sixth regulating valve (14), the #1 extraction regulating valve (15), and the #2 extraction regulating valve (16), and generate electricity at a single high load through the #1 generator (5) and the #2 generator (6). The heat required for heating is supplied from the steam heat storage hot water tank (8) to reduce extraction; During heating, the return water of the heat network is sent into the lower area of the heat absorption side of the steam heat storage hot water tank (8) through the heat network return water circulation pump (17), and then sent to the upper area of the heat absorption side of the steam heat storage hot water tank (8) through the self-circulation pump (18) to exchange heat with the extraction steam of the steam turbine in the heat release side of the steam heat storage hot water tank (8) to heat the heat network water, and then sent into the primary pipe network through the heat network supply water circulation pump (19) to supply heat to users.

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