Thermal power and compressed air energy storage coupled deep peak regulation coaxial unit

Abstract

The utility model provides a thermal power and compressed air energy storage coupled deep peak regulation coaxial unit which comprises a thermal power station boiler and further comprises a power generator, a steam turbine unit, a compressor unit, a motor / power generator and an expansion unit which are coaxially connected in sequence. The gas output end of the compressor unit is connected with the input end of the gas storage tank, and the output end of the gas storage tank is connected with the gas input end of the expansion unit; the steam turbine unit comprises a high-pressure cylinder, an intermediate-pressure cylinder and a low-pressure cylinder which are coaxially connected in sequence; a superheated steam pipeline of a thermal power station boiler is communicated with the gas input end of a high-pressure cylinder, the gas output end of a low-pressure cylinder is connected with the shell pass input end of a condenser, and the shell pass output end of the condenser is connected with the tube pass of a low-pressure heater through a condensate pump. The tube pass of the low-pressure heater is sequentially connected with the tube pass of the deaerator and the tube pass of the high-pressure heater, and the tube pass of the high-pressure heater is connected with the thermal power station boiler to form a loop. The advantages of the compressed air energy storage technology are fully exerted, peak regulation can be achieved on the premise that the operation efficiency of the thermal power generating unit is not reduced, meanwhile, the rapid regulation characteristic and flexibility of the unit are improved, and the capacity of the unit for responding to the peak regulation requirement of a power grid is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy storage, relates to energy storage peak regulation, and specifically relates to a deep peak regulation coaxial unit coupled with thermal power and compressed air energy storage. Background Art

[0002] According to statistics from the National Energy Administration, by the end of 2023, the installed capacity of renewable energy will reach 1.45 billion kilowatts, accounting for more than 50% of the country's total installed capacity of power generation, historically exceeding the installed capacity of thermal power. Currently, the total installed capacity of power generation in the country is about 2.9 billion kilowatts.

[0003] Due to the intermittent and volatile characteristics of new energy, large-scale grid connection brings about the problem of absorption. The power system consists of three parts: load, grid, and power source. In order to maintain the stability of the grid, it is necessary to achieve a dynamic balance between source and load. The large-scale access of new energy power generation brings challenges to the stability of the grid system. In terms of time, wind and solar power generation is affected by the natural environment, the power generation volatility is large, and the output is often not matched with the power load, which can easily cause fluctuations in the grid and affect the safe and stable power supply.

[0004] Deep peak regulation of thermal power units refers to a mode of operation in which power plants reduce their output and some or all units output lower than the rated minimum technical output when the peak-to-valley difference of the system load is large, resulting in difficulties in peak regulation of the power grid. Thermal power generation, as an important part of my country's electricity, accounts for a high proportion of total installed capacity (thermal power installed capacity accounts for about 50%), which determines the flexibility of thermal power unit operation and is an important way to enhance the peak regulation capacity of the power system. However, for now, the insufficient peak regulation capacity of thermal power units is also an important factor affecting the level of new energy consumption. Improving the flexibility of coal-fired power units, carrying out deep peak regulation of thermal power units, and improving peak regulation capacity on the premise of fully ensuring the safe and stable operation of the power grid are key issues in solving the problem of renewable energy consumption.

[0005] In recent years, thermal power has begun to assume more flexible regulation responsibilities. The thermal power system has an increasingly urgent demand for flexible resources. The frequent start and stop and flexible regulation of traditional units, especially during deep peak regulation, the unit output is lower than the rated minimum technical output, which brings the following main problems:

[0006] First, it increases the failure rate of equipment: when running at low load, it is easy to cause cracks on the boiler heating surface, fall off of the boiler oxide scale, and increase the failure rate of boiler auxiliary equipment.

[0007] Second, it affects the life of the equipment: frequent start-up and shutdown or deep adjustment of the unit for a long time will accelerate the loss of rotor life and reduce the actual operating life of the unit.

[0008] Third, the operating economy is reduced: if thermal power units operate under low load conditions for a long time, it will lead to reduced operating efficiency and increased energy consumption.

[0009] Fourth, emission problems increase: incomplete combustion of pulverized coal during unit start-up and shutdown and low-load combustion leads to increased emissions, causing certain pollution. Summary of the invention

[0010] In view of the shortcomings of the prior art, the purpose of the utility model is to provide a deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage, so as to solve the technical problem that thermal power units in the prior art are difficult to achieve flexible peak-shaving without reducing operating efficiency.

[0011] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0012] A deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage comprises a thermal power station boiler, and also comprises a generator, a steam turbine unit, a compressor unit, an electric / generator, and an expansion unit coaxially connected in sequence.

[0013] The gas output end of the compressor unit is connected to the input end of the gas storage tank, and the output end of the gas storage tank is connected to the gas input end of the expansion unit.

[0014] The steam turbine unit comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder which are coaxially connected in sequence; the superheated steam pipeline of the thermal power station boiler is connected to the gas input end of the high-pressure cylinder, the gas output end of the high-pressure cylinder is connected to the gas input end of the reheat pipeline, the reheat pipeline is installed in the thermal power station boiler for reheating, the output end of the reheat pipeline is connected to the gas input end of the medium-pressure cylinder, the gas output end of the medium-pressure cylinder is connected to the gas input end of the low-pressure cylinder, the gas output end of the low-pressure cylinder is connected to the shell side input end of the condenser, the shell side output end of the condenser is connected to the tube side of the low-pressure heater through a condensate pump, the tube side of the low-pressure heater is connected to the tube side of the deaerator and the tube side of the high-pressure heater in sequence, and the tube side of the high-pressure heater is connected to the thermal power station boiler to form a loop.

[0015] The utility model also has the following technical features:

[0016] Furthermore, the low-pressure cylinder is also connected to the shell-side input end of the low-pressure heater through the first exhaust pipe, and the shell-side output end of the low-pressure heater is connected to the thermal power plant boiler to form a loop; the medium-pressure cylinder is also connected to the shell-side input end of the deaerator through the second exhaust pipe, and the shell-side output end of the deaerator is connected to the thermal power plant boiler to form a loop; the high-pressure cylinder is also connected to the shell-side input end of the high-pressure heater through the third exhaust pipe, and the shell-side output end of the high-pressure heater is connected to the thermal power plant boiler to form a loop.

[0017] Furthermore, the gas output end of the compressor unit is connected to the input end of the gas storage tank through the tube side of the heat exchanger unit, and the output end of the gas storage tank is connected to the gas input end of the expansion unit through the tube side of the reheater unit.

[0018] Preferably, the shell side input end of the reheater group is connected to the second exhaust pipe to extract air, and the shell side output end of the reheater group is connected to the tube side input end of the low-pressure heater.

[0019] Preferably, the expansion machine group includes a first-stage expansion machine and a second-stage expansion machine; the reheater group includes a first reheater and a second reheater; a pipe line of the first reheater is connected between the output end of the gas storage tank and the gas input end of the first-stage expansion machine, and a pipe line of the second reheater is connected between the gas output end of the first-stage expansion machine and the gas input end of the second-stage expansion machine.

[0020] Preferably, the shell side input end of the heat exchanger group is connected to the output end of the condensate pump to take cold water, and the shell side output end of the heat exchanger group is connected to the tube side input end of the deaerator.

[0021] Preferably, the compressor unit includes a first-stage compressor, a second-stage compressor and a third-stage compressor coaxially connected in sequence; the heat exchanger group includes a first heat exchanger, a second heat exchanger and a third heat exchanger; a pipe side of the first heat exchanger is connected between the gas output end of the first-stage compressor and the gas input end of the second-stage compressor, a pipe side of the second heat exchanger is connected between the gas output end of the second-stage compressor and the gas input end of the third-stage compressor, and a pipe side of the third heat exchanger is connected between the gas output end of the third-stage compressor and the input end of the gas storage tank.

[0022] The tube side of the condenser is connected to a cooling tower to provide cooling medium.

[0023] The steam turbine unit and the compressor unit are coaxially connected via a first speed-changing clutch; the compressor unit and the electric motor / generator are coaxially connected via a second speed-changing clutch; and the electric motor / generator and the expansion unit are coaxially connected via a third speed-changing clutch.

[0024] Compared with the prior art, the utility model has the following technical effects:

[0025] (I) The utility model gives full play to the advantages of compressed air energy storage technology, and can achieve peak load regulation without reducing the operating efficiency of thermal power units, while improving the rapid regulation characteristics and flexibility of the units, and greatly increasing the ability of the units to respond to the peak load regulation needs of the power grid.

[0026] (II) The compressed air energy storage system of the utility model is coupled with a thermal power system, making full use of compression heat and boiler steam, achieving complementarity in the energy storage and energy release stages, and coupling heat and electricity. Compared with conventional advanced adiabatic compressed air energy storage systems, the heat storage unit is eliminated, the system structure is simple, and the investment is reduced.

[0027] (III) The utility model utilizes the characteristics of fast start and stop of compressed air energy storage system (generally 10 to 15 minutes to reach rated load), improves the climbing rate of thermal power system and shortens the start and stop time through coupling system, and at the same time broadens the load operation range of the system. In theory, it can achieve deep peak regulation demand of 0 to 100% load.

[0028] (IV) The whole unit system of the utility model adopts a coaxial design, with a compact structure and high output torque. At the same time, it can realize the joint operation of gas traction and electric traction, further increase the peak load regulation capacity, reduce the energy conversion links, and improve the system operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of a deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage.

[0030] The meanings of the numbers in the figure are: 1-thermal power station boiler, 2-generator, 3-steam turbine unit, 4-compressor unit, 5-electric / generator, 6-expansion unit, 7-gas storage tank, 8-cooling tower, 9-superheated steam pipe, 10-reheat pipe, 11-condenser, 12-condensate pump, 13-low-pressure heater, 14-deaerator, 15-high-pressure heater, 16-heat exchanger group, 17-reheater group, 18-first speed clutch, 19-second speed clutch, 20-third speed clutch.

[0031] 301 - high pressure cylinder, 302 - medium pressure cylinder, 303 - low pressure cylinder, 304 - first air extraction pipeline, 305 - second air extraction pipeline, 306 - third air extraction pipeline.

[0032] 401-first stage compressor, 402-second stage compressor, 403-third stage compressor.

[0033] 601-first-stage expander, 602-second-stage expander.

[0034] 1601-the first heat exchanger, 1602-the second heat exchanger, 1603-the third heat exchanger.

[0035] 1701-first reheater, 1702-second reheater.

[0036] The specific contents of the utility model are further explained in detail below in conjunction with the embodiments. DETAILED DESCRIPTION

[0037] It should be noted that, unless otherwise specified, all components and equipment in the present invention are components and equipment known in the prior art.

[0038] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of the present application fall within the protection scope of the present invention.

[0039] Example:

[0040] This embodiment provides a deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage, such as Figure 1 As shown, it includes a thermal power station boiler 1, and also includes a generator 2, a steam turbine unit 3, a compressor unit 4, a motor / generator 5, and an expansion unit 6 which are coaxially connected in sequence.

[0041] like Figure 1 As shown, the gas output end of the compressor unit 4 is connected to the input end of the gas storage tank 7 , and the output end of the gas storage tank 7 is connected to the gas input end of the expansion unit 6 .

[0042] like Figure 1 As shown, the steam turbine unit 3 includes a high-pressure cylinder 301, an intermediate-pressure cylinder 302 and a low-pressure cylinder 303 which are coaxially connected in sequence; the superheated steam pipe 9 of the thermal power station boiler 1 is connected to the gas input end of the high-pressure cylinder 301, the gas output end of the high-pressure cylinder 301 is connected to the gas input end of the reheat pipe 10, the reheat pipe 10 is installed in the thermal power station boiler 1 for reheating, the output end of the reheat pipe 10 is connected to the gas input end of the intermediate-pressure cylinder 302, the gas output end of the intermediate-pressure cylinder 302 is connected to the gas input end of the low-pressure cylinder 303, the gas output end of the low-pressure cylinder 303 is connected to the shell side input end of the condenser 11, the shell side output end of the condenser 11 is connected to the tube side of the low-pressure heater 13 through the condensate pump 12, the tube side of the low-pressure heater 13 is connected to the tube side of the deaerator 14 and the tube side of the high-pressure heater 15 in sequence, and the tube side of the high-pressure heater 15 is connected to the thermal power station boiler 1 to form a loop.

[0043] As a further solution of this embodiment, Figure 1 As shown, the low-pressure cylinder 303 is also connected to the shell-side input end of the low-pressure heater 13 through the first exhaust pipe 304, and the shell-side output end of the low-pressure heater 13 is connected to the thermal power plant boiler 1 to form a loop; the medium-pressure cylinder 302 is also connected to the shell-side input end of the deaerator 14 through the second exhaust pipe 305, and the shell-side output end of the deaerator 14 is connected to the thermal power plant boiler 1 to form a loop; the high-pressure cylinder 301 is also connected to the shell-side input end of the high-pressure heater 15 through the third exhaust pipe 306, and the shell-side output end of the high-pressure heater 15 is connected to the thermal power plant boiler 1 to form a loop.

[0044] As a further solution of this embodiment, Figure 1As shown, the gas output end of the compressor unit 4 is connected to the input end of the gas storage tank 7 through the tube side of the heat exchanger unit 16, and the output end of the gas storage tank 7 is connected to the gas input end of the expansion unit 6 through the tube side of the reheater unit 17.

[0045] As a preferred solution of this embodiment, Figure 1 As shown, the shell side input end of the reheater group 17 is connected to the second exhaust pipe 305 to extract air, and the shell side output end of the reheater group 17 is connected to the tube side input end of the low pressure heater 13.

[0046] As a preferred solution of this embodiment, Figure 1 As shown, the expander group 6 includes a primary expander 601 and a secondary expander 602; the reheater group 17 includes a first reheater 1701 and a second reheater 1702; the pipe of the first reheater 1701 is connected between the output end of the gas storage tank 7 and the gas input end of the primary expander 601, and the pipe of the second reheater 1702 is connected between the gas output end of the primary expander 601 and the gas input end of the secondary expander 602. In the energy release and power generation stage, the high-pressure gas stored in the gas storage tank 7 is used to drive and expand to do work. At the same time, in order to ensure the inlet air temperature of each level of expanders, reheaters are respectively provided at the inlet of each level of expanders. The multi-stage reheaters are used to reheat the inlet air to reach the design temperature to ensure the expansion power generation efficiency.

[0047] As a preferred solution of this embodiment, Figure 1 As shown, the shell side input end of the heat exchanger group 16 is connected to the output end of the condensate pump 12 to take cold water, and the shell side output end of the heat exchanger group 16 is connected to the tube side input end of the deaerator 14.

[0048] As a preferred solution of this embodiment, Figure 1 As shown, the compressor unit 4 includes a primary compressor 401, a secondary compressor 402 and a tertiary compressor 403 which are coaxially connected in sequence; the heat exchanger group 16 includes a first heat exchanger 1601, a second heat exchanger 1602 and a third heat exchanger 1603; the pipe pass of the first heat exchanger 1601 is connected between the gas output end of the primary compressor 401 and the gas input end of the secondary compressor 402, the pipe pass of the second heat exchanger 1602 is connected between the gas output end of the secondary compressor 402 and the gas input end of the tertiary compressor 403, and the pipe pass of the third heat exchanger 1603 is connected between the gas output end of the tertiary compressor 403 and the input end of the gas storage tank 7. The multi-stage heat exchanger is used for inter-stage heat exchange to ensure that the inlet air temperature of each stage of the compressor meets the design requirements and improve the efficiency of the compression stage.

[0049] As a preferred solution of this embodiment, Figure 1 As shown, the tube side of the condenser 11 is connected to the cooling tower 8 to provide cooling medium.

[0050] As a preferred solution of this embodiment, Figure 1 As shown, the steam turbine unit 3 and the compressor unit 4 are coaxially connected via a first speed clutch 18; the compressor unit 4 and the electric motor / generator 5 are coaxially connected via a second speed clutch 19; and the electric motor / generator 5 and the expansion unit 6 are coaxially connected via a third speed clutch 20.

[0051] In this embodiment, during the peak load instruction period, part of the electricity generated by the generator 2 is used to drive the compressor unit 4 to operate, perform air compression energy storage, and reduce the amount of electricity connected to the grid. At the same time, the steam turbine unit 3 can also directly drive the compressor unit 4 through the first speed change clutch 18, and further reduce the amount of electricity connected to the grid by the generator 2 according to the peak load instruction, further meeting the needs of deep peak load regulation.

[0052] When the deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage of the utility model is in use, the operation modes include:

[0053] Mode 1: Energy storage deep peak regulation mode:

[0054] The operation period of this mode is mainly manifested in the period when the amount of renewable energy power generation connected to the grid is large, or the user load is small, when the overall power supply exceeds the demand, in order to increase the consumption of renewable energy and achieve supply and demand balance, it is necessary to reduce the output of thermal power units. When the amount of electricity connected to the grid is less than the minimum technical load of the unit, it is manifested as deep peak regulation.

[0055] At this time, the user load is low, and the power plant receives the peak load regulation instruction, and regulates the peak load downward to reduce the amount of electricity connected to the grid. At this time, the steam turbine unit 3 drives the generator 2 to generate excess electricity, and the motor / generator 5 in the motor mode drives the compressor unit 4 to compress the air, converting the electrical energy into air pressure energy storage; in order to compress the air to the designed pressure, the compressor unit 4 generally adopts multi-stage compression. The compressed air temperature rises, and the power consumption w of each compressor during the compression process meets:

[0056]

[0057] Where:

[0058] m is the compressor air mass flow rate;

[0059] η is the isentropic efficiency of the compressor;

[0060] k is the adiabatic index;

[0061] R g is the air gas constant;

[0062] T in is the compressor inlet gas temperature;

[0063] β is the compressor pressure ratio.

[0064] It can be seen from the above formula that by reducing the compressor inlet air temperature T in , to reduce the power consumption of the compressor and improve the system efficiency. Therefore, the first heat exchanger 1601, the second heat exchanger 1602 and the third heat exchanger 1603 are set between each stage of the compressor to reduce the inlet temperature of the next stage of the compressor. The hot end of each stage of the heat exchanger is connected to the compressor outlet, and the cold end uses part of the condensed water at about 40°C after passing through the condenser 11. After the compressed air temperature is reduced after heat exchange, it enters the next stage of the compressor. At the same time, the condensed water heated after heat exchange returns to the input end of the deaerator 14, and enters the thermal power plant boiler 1 after further heating and pressurization. The temperature and pressure of the condensed water after heating by the heat exchanger are increased, which can reduce the exhaust of the steam turbine, reduce the steam consumption of the high-pressure heater 15 and the low-pressure heater 13, and at the same time reduce the energy consumption of the thermal power plant boiler 1, and improve the system efficiency of the energy storage stage. At the same time, due to the coaxial unit design, by closing the first speed clutch 18, while performing deep peak regulation, the steam turbine can be used to directly drive the compressor to replace the multiple conversions of original thermal energy-electrical energy-mechanical energy, thereby reducing energy consumption in the energy storage process and further improving system efficiency.

[0065] Mode 2: Energy release and deep peak regulation mode:

[0066] The operation period of this mode is mainly manifested in the period when the amount of renewable energy power generation connected to the grid is small, or the user load is large, and the overall power supply is less than the demand. In order to achieve supply and demand balance, it is necessary to increase the output of thermal power units. When the amount of electricity connected to the grid is greater than the rated technical load of the unit, it is manifested as deep peak regulation.

[0067] At this time, the user load is high, and the power plant receives the peak load regulation instruction, regulates the peak load upward, and increases the amount of electricity connected to the grid. At this time, the steam turbine unit 3 drives the generator 2 to increase the power generation. At this time, the compressor unit 4 is disengaged from the coaxial system through the first speed clutch 18 and the second speed clutch 19 and stops running; the electric motor / generator 5 switches to the generator mode and is connected to the expansion unit 6 through the third speed clutch 20. The compressed air stored in the gas tank 7 is released to drive the expansion unit 6 to rotate, drive the electric motor / generator 5 to generate electricity, and convert the pressure energy into electrical energy. On the original coal-fired steam generator unit, the compressed air power generation is increased, the overall power generation of the power plant is improved, and deep peak regulation is achieved.

[0068] The expansion unit 6 generally adopts multi-stage expansion. The temperature of the air after expansion decreases, and each stage of the expansion unit performs work w during the expansion process. ′ satisfy:

[0069]

[0070] in:

[0071] m t is the expander air mass flow rate;

[0072] k is the adiabatic index;

[0073] R g is the air gas constant;

[0074] T i ′ n is the expander inlet gas temperature;

[0075] β is the expansion ratio;

[0076] η ′ is the isentropic efficiency of the expander.

[0077] It can be seen from the above formula that by increasing the expander inlet air temperature T i ′ n , to improve the work capacity of the expander and increase the power generation. Therefore, the first reheater 1701 and the second reheater 1702 are set at the entrance of each stage of the expander to increase the inlet temperature of the expander. The hot end of each stage of the reheater is connected to the exhaust pipe of the turbine. After heat exchange, the air temperature rises to the design temperature and enters the expander to do work. At the same time, the exhaust air temperature is reduced after heat exchange and returned to the condensate network as condensate. After multi-stage expansion, the air pressure drops to normal pressure and is emptied to complete the energy release and peak regulation operation.

[0078] Application examples:

[0079] This application example provides a deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage based on the above-mentioned embodiment, and performs analysis and calculation using a 660MW ultra-supercritical gas-condensing thermal power unit as an analysis model.

[0080] According to the power plant operating load, the range of 70% to 50% of the rated output belongs to mandatory peak regulation, that is, the normal adjustment range of the unit. The peak regulation service below 50% load is the requirement of deep peak regulation. This plan configures compressed air energy storage according to the deep peak regulation amplitude of 23.3% (that is, the minimum output of the thermal power unit is reduced to 26.7% of the rated load).

[0081] The peak-shaving duration is 5h / day, and the peak-shaving period is 330 days per year.

[0082] A 100MW compressed air energy storage coupling scheme is selected, adopting a charge-5-discharge-5 operation mode.

[0083] The coal cost of thermal power units is calculated at 750 yuan / t, and the on-grid electricity price of power plants is calculated at 0.42 yuan / kWh. The peak-shaving compensation refers to the deep peak-shaving compensation standard for conventional coal-fired power generation units in the "Implementation Rules for the Grid-connected Operation and Management of the East China Region": the compensation standard is calculated at 320 yuan / MWh for load rates below 30%.

[0084] The thermal power unit is selected to operate at 50% of the rated load as the benchmark operating condition, and the minimum output of the thermal power unit is reduced to 26.7% of the rated load as the deep peak regulation target. A comparative analysis is conducted between the forced deep peak regulation of the thermal power unit and the energy storage coupling deep peak regulation scheme of the utility model. The specific calculation results are shown in Table 1.

[0085] Table 1 Comparison of forced deep peak regulation of thermal power units and energy storage coupling deep peak regulation of the utility model

[0086]

[0087] Through the analysis of Table 1 above, it can be seen that after adopting the coupled energy storage system of the utility model (i.e., the deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage), the unit corrected power generation coal consumption of the coupled system increases, but after receiving the peak-shaving instruction operation, the total power generation of the coupled system increases compared with the power generation of the unit forced peak-shaving, and the hourly net power generation income also increases. Therefore, the utility model is not only beneficial to improving the performance of power plant unit equipment, but also has good practical significance for improving the economic efficiency of power plant operation.

[0088] Table 2 Cost and benefits of the coupled energy storage system of the utility model

[0089]

[0090] From the analysis of Table 2 above, it can be seen that the use of the coupled energy storage system of the utility model causes incremental investment and brings incremental benefits, and the incremental investment payback period is 7.06 years.

[0091] Table 3 Comparison of cost-benefit of deep peak regulation of coupled energy storage system and forced deep peak regulation of units in the utility model

[0092]

[0093] From the analysis of Table 3 above, it can be seen that, compared with the deep peak regulation of the coupled energy storage system of the utility model and the forced deep peak regulation of the unit, although the coupling scheme increases the investment in the energy storage system, it also increases the system life and the net income during the life cycle.

[0094] In terms of improving the ramp rate of thermal power units, according to the startup speed of 10 to 15 minutes for compressed air energy storage to reach the rated load, according to the above-mentioned installed capacity, the load ramp rate can be increased by 6.7 to 10 MW / min. At present, the ramp rate of most thermal power units is 1-1.5% rated load / min, that is, the coupling scheme can increase the ramp rate to 2-3% rated load / min based on the original thermal power unit ramp rate, thereby improving the original unit ramp rate and increasing the unit flexibility.

[0095] Therefore, the technical solution of the present invention can not only improve the service life of the thermal power units in the power plant, but also improve the flexibility of the thermal power units, realize the needs of rapid start and stop, ramp climbing and deep peak regulation of the thermal power units, improve the operating conditions, and at the same time can increase the operating income of the power plant. Therefore, the present invention has great practical engineering significance.

Claims

1. A deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage, comprising a thermal power station boiler (1), characterized in that: It also includes a generator (2), a steam turbine unit (3), a compressor unit (4), a motor / generator (5), and an expansion unit (6) which are coaxially connected in sequence; The gas output end of the compressor unit (4) is connected to the input end of the gas storage tank (7), and the output end of the gas storage tank (7) is connected to the gas input end of the expansion unit (6); The steam turbine unit (3) comprises a high-pressure cylinder (301), an intermediate-pressure cylinder (302) and a low-pressure cylinder (303) which are coaxially connected in sequence; the superheated steam pipe (9) of the thermal power station boiler (1) is connected to the gas input end of the high-pressure cylinder (301), the gas output end of the high-pressure cylinder (301) is connected to the gas input end of the reheat pipe (10), the reheat pipe (10) is installed in the thermal power station boiler (1) for reheating, and the output end of the reheat pipe (10) is connected to the gas input end of the intermediate-pressure cylinder (302). The gas output end of the medium-pressure cylinder (302) is connected to the gas input end of the low-pressure cylinder (303), the gas output end of the low-pressure cylinder (303) is connected to the shell-side input end of the condenser (11), the shell-side output end of the condenser (11) is connected to the tube side of the low-pressure heater (13) through the condensate pump (12), the tube side of the low-pressure heater (13) is connected to the tube side of the deaerator (14) and the tube side of the high-pressure heater (15) in turn, and the tube side of the high-pressure heater (15) is connected to the boiler (1) of the thermal power station to form a loop.

2. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage according to claim 1, characterized in that: The low-pressure cylinder (303) is also connected to the shell side input end of the low-pressure heater (13) through the first exhaust pipe (304), and the shell side output end of the low-pressure heater (13) is connected to the thermal power station boiler (1) to form a loop; the medium-pressure cylinder (302) is also connected to the shell side input end of the deaerator (14) through the second exhaust pipe (305), and the shell side output end of the deaerator (14) is connected to the thermal power station boiler (1) to form a loop; the high-pressure cylinder (301) is also connected to the shell side input end of the high-pressure heater (15) through the third exhaust pipe (306), and the shell side output end of the high-pressure heater (15) is connected to the thermal power station boiler (1) to form a loop.

3. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage as claimed in claim 2, characterized in that: The gas output end of the compressor unit (4) is connected to the input end of the gas storage tank (7) through the tube side of the heat exchanger unit (16), and the output end of the gas storage tank (7) is connected to the gas input end of the expansion unit (6) through the tube side of the reheater unit (17).

4. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage as claimed in claim 3, characterized in that: The shell side input end of the reheater group (17) is connected to the second exhaust pipe (305) to extract air, and the shell side output end of the reheater group (17) is connected to the tube side input end of the low-pressure heater (13).

5. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage as claimed in claim 4, characterized in that: The expansion machine group (6) includes a first-stage expansion machine (601) and a second-stage expansion machine (602); the reheater group (17) includes a first reheater (1701) and a second reheater (1702); a pipe line of the first reheater (1701) is connected between the output end of the gas storage tank (7) and the gas input end of the first-stage expansion machine (601), and a pipe line of the second reheater (1702) is connected between the gas output end of the first-stage expansion machine (601) and the gas input end of the second-stage expansion machine (602).

6. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage as claimed in claim 3, characterized in that: The shell side input end of the heat exchanger group (16) is connected to the output end of the condensate pump (12) to take cold water, and the shell side output end of the heat exchanger group (16) is connected to the tube side input end of the deaerator (14).

7. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage according to claim 6, characterized in that: The compressor unit (4) comprises a primary compressor (401), a secondary compressor (402) and a tertiary compressor (403) which are coaxially connected in sequence; the heat exchanger unit (16) comprises a first heat exchanger (1601), a second heat exchanger (1602) and a third heat exchanger (1603); a pipe side of the first heat exchanger (1601) is connected between the gas output end of the primary compressor (401) and the gas input end of the secondary compressor (402), a pipe side of the second heat exchanger (1602) is connected between the gas output end of the secondary compressor (402) and the gas input end of the tertiary compressor (403), and a pipe side of the third heat exchanger (1603) is connected between the gas output end of the tertiary compressor (403) and the input end of the gas storage tank (7).

8. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage according to claim 1, characterized in that: The tube side of the condenser (11) is connected to a cooling tower (8) to provide cooling medium.

9. The deep peak-shaving coaxial unit coupled with thermal power and compressed air energy storage according to claim 1, characterized in that: The steam turbine unit (3) and the compressor unit (4) are coaxially connected via a first speed-changing clutch (18); the compressor unit (4) and the electric motor / generator (5) are coaxially connected via a second speed-changing clutch (19); and the electric motor / generator (5) and the expansion unit (6) are coaxially connected via a third speed-changing clutch (20).

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