A thermal power plant coupled high-efficiency compression heat pump energy storage peak regulation system and method

Abstract

The present invention discloses a thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system and method, comprising a boiler, a turbine, a generator, a power switch, a compressor, a Freon-flue gas heat exchanger, a condensing heat exchanger, an air compressor, a throttle valve, an evaporative heat exchanger, an output pipeline, a mixing header, a heat network return water storage tank and a heat network supply water storage tank. The system and method can meet the requirements of flexible deep peak-shaving of thermal power plant units and have the characteristics of high safety and economy.

Description

Technical Field

[0001] The present invention belongs to the field of deep peak regulation of thermal power plants, and relates to a thermal power plant coupled high-efficiency compression heat pump energy storage peak regulation system and method. Background Art

[0002] With the changes in the national power policy in recent years, the main functions of thermal power plants have also changed, from being the main power supplier to participating in and cooperating with the power grid to carry out deep peak regulation. At the same time, the state has introduced a policy of subsidies for deep peak regulation electricity prices, which has greatly stimulated the enthusiasm of thermal power plants to carry out deep peak regulation transformation of units. At present, thermal power is facing the risk of structural overcapacity, and new energy is facing great pressure to absorb. Thermal power is bound to give way to the development of new energy. Thermal power units are facing deep peak regulation. For the "Three Norths" region, the contradiction between wind and fire 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 demand for heating and the continuous increase in clean energy installed capacity have resulted in very limited peak regulation space. Especially in the Northeast, most of the thermal power is cogeneration units, and the peak regulation capacity is only 10%, which affects the absorption of new energy stocks and the development of new energy increments. The hard gap in peak regulation capacity has caused serious power restrictions on new energy in some regions, resulting in thermal power units only being able to achieve deep peak regulation through transformation.

[0003] At present, the units involved in deep peak regulation have been operating at deviations from the design value for a long time, resulting in a decrease in the safety and economy of the units. From the perspective of the technologies and transformation practices adopted, the transformed units have different degrees of problems with the safety of boiler low-load stable combustion and hydrodynamic circulation, the full-load operation of the denitrification device and the low-load cooling of the turbine, the flexibility of the control system during long-term low load and rapid load changes, the equipment operation cycle and life attenuation, and the thermal-electric decoupling of the heating unit, all of which need to be further tackled and optimized. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system and method, which can meet the requirements of flexible deep peak-shaving of thermal power plant units and has the characteristics of high safety and economy.

[0005] To achieve the above-mentioned object, the thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system of the present invention comprises a boiler, a turbine, a generator, a power switch, a compressor, a Freon-flue gas heat exchanger, a condensing heat exchanger, an air compressor, a throttle valve, an evaporative heat exchanger, an output pipeline, a mixing header, a heat network return water storage tank and a heat network supply water storage tank;

[0006] A high-temperature superheater, a low-temperature superheater, an economizer and an SCR denitration device are arranged in the flue gas flow direction of the tail flue of the boiler in sequence. The outlet of the high-temperature superheater is connected to the inlet of the turbine, the output shaft of the turbine is connected to the driving shaft of the generator, and the output end of the generator is connected to the compressor through the power switch;

[0007] The tail flue is provided with a smoke exhaust port and a smoke inlet, wherein the smoke exhaust port is located between the high-temperature superheater and the low-temperature superheater, the outlet of the smoke exhaust port is connected to the heat release side inlet of the Freon-smoke heat exchanger, the heat release side outlet of the Freon-smoke heat exchanger is connected to the smoke inlet, wherein the smoke inlet is located between the economizer and the SCR denitrification device;

[0008] The outlet of the compressor is connected to the inlet of the air compressor through the heat absorption side of the Freon-flue gas heat exchanger and the heat release side of the condensing heat exchanger. The outlet of the air compressor is connected to the heat absorption side inlet of the evaporative heat exchanger through the throttle valve. The heat absorption side outlet of the evaporative heat exchanger is connected to the inlet of the compressor.

[0009] The circulating cooling water outlet of the condenser is connected with the heat release side inlet of the evaporative heat exchanger, the heat absorption side outlet of the evaporative heat exchanger is divided into two paths, one of which is connected with the output pipe, and the other is connected with the inlet of the mixing header, the outlet of the heat network return water storage tank is connected with the inlet of the mixing header, the outlet of the mixing header is connected with the heat absorption side inlet of the condensing heat exchanger, and the heat absorption side outlet of the condensing heat exchanger is connected with the inlet of the heat network supply water storage tank.

[0010] The outlet of the smoke exhaust port is connected to the heat release side inlet of the Freon-smoke heat exchanger through the #1 electric gate valve and the high-temperature and high-pressure fan.

[0011] The heat release side outlet of the Freon-flue gas heat exchanger is connected to the flue gas inlet via the #2 electric gate valve.

[0012] The air compressor is a piston type air compressor.

[0013] The heat absorption side outlet of the evaporative heat exchanger is divided into two paths after passing through the #1 electric regulating valve, one of which is connected to the output pipeline, and the other is connected to the inlet of the mixing header through the #2 electric regulating valve and the circulating water pump.

[0014] It also includes a heat network return water circulation pump and a heat network water supply circulation pump. The outlet of the heat network return water circulation pump is connected to the inlet of the heat network return water storage tank; the outlet of the heat network water supply storage tank is connected to the heat network water supply circulation pump.

[0015] The circulating cooling water outlet of the condenser is connected to the heat release side inlet of the evaporative heat exchanger through a condenser circulating water pump.

[0016] A method for peak-shaving energy storage by coupling a high-efficiency compression heat pump in a thermal power plant comprises the following steps:

[0017] When the thermal power unit needs deep peak regulation, close the power switch to power on the compressor, extract high-temperature flue gas through the flue gas outlet, and send it to the Freon-flue gas heat exchanger for heat release. The Freon output by the compressor enters the Freon-flue gas heat exchanger for isobaric reheating. The flue gas after heat release enters the tail flue and then enters the SCR denitrification device for denitrification treatment to reduce the heat absorption of the low-temperature superheater and economizer, and then reduce the evaporation and power generation of the boiler to achieve boiler peak regulation. At the same time, the compressor operation increases the plant power consumption and reduces the power supplied to the outside world to achieve boiler peak regulation.

[0018] The high-temperature and high-pressure medium output from the Freon-flue gas heat exchanger enters the condensing heat exchanger to release heat. The return water from the heat network and the cooling water output from the heat release side of the evaporative heat exchanger are mixed in the mixing header and then enter the condensing heat exchanger to absorb heat, and then stored in the water supply tank of the heat network; the Freon output from the heat release side of the condensing heat exchanger enters the air compressor, uses the high pressure to push the piston, converts the high-pressure air to store energy, and then enters the evaporative heat exchanger after the pressure is reduced by the throttle valve to exchange heat with the circulating cooling water to absorb the low-grade heat source in the circulating cooling water;

[0019] When the power generation demand of the thermal power unit increases, the power switch is disconnected and the boiler runs alone to generate electricity. At this time, the required heat is supplied by the heat stored in the water supply tank of the heating network to reduce air extraction and increase power generation.

[0020] The present invention has the following beneficial effects:

[0021] The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system and method described in the present invention is specifically operated. When the unit needs to perform deep peak-shaving, the power switch is closed, the compressor starts to work, and a high-temperature flue gas is drawn from the tail flue of the boiler. Then the heat of the high-temperature flue gas is stored in the water supply tank of the heat network through the Freon-flue gas heat exchanger, the condensing heat exchanger and the evaporating heat exchanger, so as to reduce the amount of steam entering the steam turbine, and then reduce the power generation of the generator. At the same time, the compressor is provided with power by the generator to reduce the external power supply. When the power generation and power supply demand of the thermal power unit increases, the power switch is turned off, the compressor stops working, and the boiler runs alone to generate electricity. The heat required in this stage is supplied by the heat stored in the water supply tank of the heat network, reducing air extraction and increasing power generation to meet the heating demand, while meeting the requirements of flexible deep peak-shaving of the thermal power plant units, and has the characteristics of simple system, high energy utilization efficiency and large potential for deep peak-shaving, and high safety and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention.

[0023] Among them, 1 is a boiler, 2 is a high-temperature superheater, 3 is a low-temperature superheater, 4 is an economizer, 5 is a turbine, 6 is a generator, 7 is a power switch, 8 is a compressor, 9 is a Freon-flue gas heat exchanger, 10 is a condensing heat exchanger, 11 is a piston air compressor, 12 is a throttle valve, 13 is an evaporative heat exchanger, 14 is a #1 electric gate valve, 15 is a high-temperature and high-pressure fan, 16 is a #2 electric gate valve, 17 is a heating network water supply storage tank, 18 is a heating network water supply circulating pump, 19 is a heating network return water storage tank, 20 is a heating network return water circulating pump, 21 is a #1 electric regulating valve, 22 is a #2 electric regulating valve, 23 is a circulating water pump, 24 is a mixing header, and 25 is a condenser circulating water pump. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0025] refer to Figure 1 The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system of the present invention comprises a boiler 1, a turbine 5, a generator 6, a power switch 7, a compressor 8, a Freon-flue gas heat exchanger 9, a condensing heat exchanger 10, an air compressor 11, a throttle valve 12, an evaporative heat exchanger 13, an output pipeline, a mixing header 24, a heat network return water storage tank 19 and a heat network supply water storage tank 17; a high-temperature superheater 2, a low-temperature superheater 3 and a low-temperature superheater 4 are arranged in the flue gas flow direction of the tail flue of the boiler 1. 3. Economizer 4 and SCR denitration device. The outlet of high-temperature superheater 2 is connected to the inlet of turbine 5. The output shaft of turbine 5 is connected to the driving shaft of generator 6. The output end of generator 6 is connected to compressor 8 via power switch 7. The tail flue is provided with a smoke exhaust port and a smoke inlet. The smoke exhaust port is located between high-temperature superheater 2 and low-temperature superheater 3. The outlet of smoke exhaust port is connected to the heat release side inlet of Freon-smoke heat exchanger 9. The outlet of the heat release side of the flue gas heat exchanger 9 is connected to the flue gas inlet, wherein the flue gas inlet is located between the economizer 4 and the SCR denitration device; the outlet of the compressor 8 is connected to the inlet of the air compressor 11 through the heat absorption side of the Freon-flue gas heat exchanger 9 and the heat release side of the condensing heat exchanger 10, and the outlet of the air compressor 11 is connected to the heat absorption side inlet of the evaporative heat exchanger 13 through the throttle valve 12, and the heat absorption side outlet of the evaporative heat exchanger 13 is connected to the inlet of the compressor 8; the circulation of the condenser The cooling water outlet is connected to the heat release side inlet of the evaporative heat exchanger 13. The heat absorption side outlet of the evaporative heat exchanger 13 is divided into two paths, one of which is connected to the output pipe, and the other is connected to the inlet of the mixing header 24. The outlet of the heat network return water storage tank 19 is connected to the inlet of the mixing header 24. The outlet of the mixing header 24 is connected to the heat absorption side inlet of the condensing heat exchanger 10. The heat absorption side outlet of the condensing heat exchanger 10 is connected to the inlet of the heat network supply water storage tank 17.

[0026] The outlet of the smoke exhaust port is connected to the heat release side inlet of the Freon-smoke heat exchanger 9 through the #1 electric gate valve 14 and the high-temperature and high-pressure fan 15; the heat release side outlet of the Freon-smoke heat exchanger 9 is connected to the smoke inlet through the #2 electric gate valve 16.

[0027] The heat absorption side outlet of the evaporative heat exchanger 13 is divided into two paths after passing through the #1 electric regulating valve 21, one of which is connected to the output pipeline, and the other is connected to the inlet of the mixing header 24 through the #2 electric regulating valve 22 and the circulating water pump 23.

[0028] The present invention also includes a heating network return water circulation pump 20 and a heating network supply water circulation pump 18, the outlet of the heating network return water circulation pump 20 is connected to the inlet of the heating network return water storage tank 19; the outlet of the heating network supply water storage tank 17 is connected to the heating network supply water circulation pump 18.

[0029] The circulating cooling water outlet of the condenser is connected to the heat release side inlet of the evaporative heat exchanger 13 through a condenser circulating water pump 25, and the air compressor 11 is a piston air compressor.

[0030] The method for peak-shaving energy storage by coupling a high-efficiency compression heat pump to a thermal power plant of the present invention comprises the following steps:

[0031] When the thermal power unit needs deep peak regulation, the power switch 7 is closed to power on the compressor 8, and the high-temperature flue gas is extracted through the flue gas outlet and sent to the Freon-flue gas heat exchanger 9 for heat release. The Freon output by the compressor 8 enters the Freon-flue gas heat exchanger 9 for isobaric reheating. The flue gas after heat release enters the tail flue and then enters the SCR denitration device for denitration treatment to reduce the heat absorption of the low-temperature superheater 3 and the economizer 4, thereby reducing the evaporation and power generation of the boiler 1, and realizing the peak regulation of the boiler 1. At the same time, the operation of the compressor 8 increases the plant power consumption and reduces the power supplied to the outside, realizing the peak regulation of the boiler 1.

[0032] The high-temperature and high-pressure medium outputted from the Freon-flue gas heat exchanger 9 enters the condensing heat exchanger 10 to release heat. The return water from the heat network and the cooling water outputted from the heat release side of the evaporative heat exchanger 13 are mixed in the mixing header 24 and then enter the condensing heat exchanger 10 to absorb heat, and then are stored in the heat network water supply storage tank 17. The Freon outputted from the heat release side of the condensing heat exchanger 10 enters the air compressor 11, and uses the high pressure to push the piston, converting the high-pressure air to store energy, and then after the pressure is reduced by the throttle valve 12, enters the evaporative heat exchanger 13 to exchange heat with the circulating cooling water, so as to absorb the low-grade heat source in the circulating cooling water.

[0033] When the power generation demand of the thermal power unit increases, the power switch 7 is disconnected and the boiler 1 operates alone to generate electricity. At this time, the required heat is supplied by the heat stored in the heat network water supply tank 17 to reduce air extraction and increase power generation.

[0034] Embodiment 1

[0035] The specific operation process of this embodiment is as follows:

[0036] When the thermal power unit needs deep peak regulation, open the #1 electric gate valve 14 and the #2 electric gate valve 16, start the high-temperature and high-pressure fan 15; close the power switch 7 to energize the compressor 8; start the heat network return water circulation pump 20 and the heat network return water circulation pump 20; start the condenser circulating water pump 25, and open the #1 electric regulating valve 21.

[0037] When the power grid requires the unit to have a peak load of 30%, the operating load of boiler 1 can reach 40%, and the excess 10% of heat and power generation are stored and efficiently utilized through the high-efficiency compression pump system, that is, 5-10% of the 600°C high-temperature flue gas is extracted through the high-temperature and high-pressure fan 15 and sent to the Freon-flue gas heat exchanger 9 for heat release. The 2MPa, 150°C Freon output by the compressor 8 enters the Freon-flue gas heat exchanger 9 for isobaric reheating to 250°C. The flue gas after heat release enters the tail flue and then enters the SCR denitrification device for denitrification treatment to reduce the heat absorption of the low-temperature superheater 3 and the economizer 4, thereby reducing the evaporation and power generation of boiler 1 and achieving peak load regulation of boiler 1. On the other hand, the operation of compressor 8 increases the factory power consumption and reduces the amount of power supplied to the outside world, thereby achieving peak load regulation of boiler 1;

[0038] The 250°C, 2MPa high-temperature and high-pressure medium output by the Freon-flue gas heat exchanger 9 enters the condensing heat exchanger 10 for heat release, and the 45°C heat network return water and the 10°C water output by the circulating water pump 23 are mixed in the mixing header 24 and then enter the condensing heat exchanger 10 to absorb heat. The water is heated to 95°C and then stored in the heat network water supply storage tank 17; the 60°C, 2MPa Freon output by the heat release side of the condensing heat exchanger 10 enters the air compressor 11, and the high pressure is used to push the piston to convert the high-pressure air for energy storage, and then the working medium is adjusted to 0.1MPa, 0°C through the throttle valve 12, and then sent to the evaporative heat exchanger 13 for heat exchange with the circulating cooling water to absorb the low-grade heat source in the circulating cooling water, so as to reduce the temperature of the cooling water from 25°C to 10°C.

[0039] When the power generation demand of the thermal power unit increases, the power switch 7 is turned off, and the boiler 1 runs alone to generate electricity. The heat required in this stage is supplied by the heat stored in the heat network water supply tank 17, which reduces air extraction and increases power generation.

[0040] In addition, it should be noted that the present invention improves the parameters of Freon in the heat pump system, reduces the inlet water temperature of the condenser heat exchanger, and simultaneously provides a piston air compressor, so that the heat pump energy efficiency coefficient COP is greatly improved.

Claims

1. A thermal power plant coupled with a high-efficiency compression heat pump energy storage peak-shaving system, characterized in that: It includes a boiler (1), a turbine (5), a generator (6), a power switch (7), a compressor (8), a freon-flue gas heat exchanger (9), a condensing heat exchanger (10), an air compressor (11), a throttle valve (12), an evaporative heat exchanger (13), an output pipeline, a mixing header (24), a heat network return water storage tank (19) and a heat network supply water storage tank (17); A high-temperature superheater (2), a low-temperature superheater (3), an economizer (4) and an SCR denitration device are arranged in sequence in the flue gas flow direction of the tail flue of the boiler (1); the outlet of the high-temperature superheater (2) is connected to the inlet of the turbine (5); the output shaft of the turbine (5) is connected to the drive shaft of the generator (6); and the output end of the generator (6) is connected to the compressor (8) via a power switch (7); The tail flue is provided with a smoke exhaust port and a smoke inlet, wherein the smoke exhaust port is located between the high-temperature superheater (2) and the low-temperature superheater (3), the outlet of the smoke exhaust port is connected to the heat release side inlet of the Freon-smoke heat exchanger (9), the heat release side outlet of the Freon-smoke heat exchanger (9) is connected to the smoke inlet, wherein the smoke inlet is located between the economizer (4) and the SCR denitration device; The outlet of the compressor (8) is connected to the inlet of the air compressor (11) via the heat absorption side of the Freon-flue gas heat exchanger (9) and the heat release side of the condensing heat exchanger (10); the outlet of the air compressor (11) is connected to the heat absorption side inlet of the evaporative heat exchanger (13) via the throttle valve (12); and the heat absorption side outlet of the evaporative heat exchanger (13) is connected to the inlet of the compressor (8); The circulating cooling water outlet of the condenser is connected to the heat release side inlet of the evaporative heat exchanger (13); the heat absorption side outlet of the evaporative heat exchanger (13) is divided into two paths, one of which is connected to the output pipeline, and the other is connected to the inlet of the mixing header (24); the outlet of the heat network return water storage tank (19) is connected to the inlet of the mixing header (24); the outlet of the mixing header (24) is connected to the heat absorption side inlet of the condensing heat exchanger (10); and the heat absorption side outlet of the condensing heat exchanger (10) is connected to the inlet of the heat network supply water storage tank (17); The outlet of the smoke exhaust port is connected to the heat release side inlet of the Freon-smoke heat exchanger (9) via the #1 electric gate valve (14) and the high-temperature and high-pressure fan (15); The heat release side outlet of the Freon-flue gas heat exchanger (9) is connected to the flue gas inlet via the #2 electric gate valve (16).

2. The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system according to claim 1 is characterized in that: The air compressor (11) is a piston type air compressor.

3. The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system according to claim 1 is characterized in that: The heat absorption side outlet of the evaporative heat exchanger (13) is divided into two paths after passing through the #1 electric regulating valve (21), one of which is connected to the output pipeline, and the other is connected to the inlet of the mixing header (24) through the #2 electric regulating valve (22) and the circulating water pump (23).

4. The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system according to claim 1 is characterized in that: It also includes a heating network return water circulation pump (20) and a heating network supply water circulation pump (18), wherein the outlet of the heating network return water circulation pump (20) is connected to the inlet of the heating network return water storage tank (19); and the outlet of the heating network supply water storage tank (17) is connected to the heating network supply water circulation pump (18).

5. The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system according to claim 1 is characterized in that: The circulating cooling water outlet of the condenser is connected to the heat release side inlet of the evaporative heat exchanger (13) via a condenser circulating water pump (25).

6. A method for peak-shaving energy storage by coupling a high-efficiency compression heat pump to a thermal power plant, characterized in that: The thermal power plant coupled high-efficiency compression heat pump energy storage peak-shaving system according to claim 1 comprises the following steps: When the thermal power unit needs deep peak regulation, the power switch (7) is closed to power on the compressor (8), and the high-temperature flue gas is extracted through the flue gas extraction port and sent to the Freon-flue gas heat exchanger (9) for heat release. The Freon output by the compressor (8) enters the Freon-flue gas heat exchanger (9) for isobaric reheating. The flue gas after heat release enters the tail flue and then enters the SCR denitration device for denitration treatment, so as to reduce the heat absorption of the low-temperature superheater (3) and the economizer (4), thereby reducing the evaporation amount and power generation of the boiler (1), thereby achieving peak regulation of the boiler (1). At the same time, the operation of the compressor (8) increases the plant power consumption and reduces the power supplied to the outside, thereby achieving peak regulation of the boiler (1); The high-temperature and high-pressure medium output from the Freon-flue gas heat exchanger (9) enters the condensing heat exchanger (10) to release heat, and the return water from the heat network and the cooling water output from the heat release side of the evaporative heat exchanger (13) are mixed in the mixing header (24) and then enter the condensing heat exchanger (10) to absorb heat, and then are stored in the heat network water supply storage tank (17); the Freon output from the heat release side of the condensing heat exchanger (10) enters the air compressor (11), uses the high pressure to push the piston, converts the high-pressure air to store energy, and then enters the evaporative heat exchanger (13) after the pressure is reduced by the throttle valve (12) to exchange heat with the circulating cooling water, so as to absorb the low-grade heat source in the circulating cooling water; When the power generation demand of the thermal power unit increases, the power switch (7) is disconnected and the boiler (1) operates alone to generate electricity. At this time, the required heat supply is provided by the heat stored in the heat supply water storage tank (17) of the heat network, so as to reduce air extraction and increase power generation.

Images