New energy and pneumoelectric coupled low-carbon-based charge source

Abstract

The invention provides a new energy and gas-electricity coupled low-carbon-based charge source. The new energy and gas-electricity coupled low-carbon-based charge source comprises a new energy power generation field, a fused salt heat storage system, a gas power station and a power generation system. The fused salt heat storage system is of a cold and hot tank circulation structure, and the new energy power plant is connected with the fused salt heat storage system through the first heat exchange unit. The fused salt heat storage system is connected with the power generation system through the second heat exchange unit; the gas power station is connected with the power generation system through the third heat exchange unit. Energy conversion and space-time translation of heat energy are achieved through the new energy heat exchange coupling and fused salt heat storage technology, and a stable base charge power source is formed; wherein the gas unit is used as a flexible adjusting power supply, and is used for quickly responding when the new energy output is suddenly reduced or the load is suddenly increased so as to make up a power gap; according to the cooperative operation mode, the flexibility advantage of gas power generation is brought into play, the dependence degree on gas resources is reduced through new energy replacement, meanwhile, overall carbon emission reduction of the system is achieved, and the system conforms to the clean, low-carbon, safe and efficient energy development direction.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy power supply systems, and particularly to a low-carbon base load power source integrating new energy and gas power. Background Art

[0002] Under the background of the global low-carbon energy demand, building a new power system with new energy as the main body has become one of the important goals. Among them, with the continuous increase in the penetration rate of renewable energy power generation such as wind power and photovoltaic power, its inherent randomness, volatility, and intermittency characteristics pose severe challenges to the frequency stability, active power balance ability, and flexible regulation ability of the power system. Specifically, the high proportion of new energy access leads to a reduction in system inertia, a shortage of frequency regulation resources, an increase in the risk of curtailment of electricity, and it is difficult for the traditional power source structure mainly based on synchronous machines to meet the operation requirements of a high proportion of renewable energy and a high-power electronic equipment system. How to improve the new energy consumption capacity and maintain the system safety and stability while ensuring power supply reliability has become a key technical problem in the current power field.

[0003] Gas power generation, with its technical characteristics such as fast start-stop speed, wide load regulation range, and high active power response rate, has become an ideal transitional power source for connecting the high proportion of new energy consumption. Its flexible regulation ability can effectively suppress the output fluctuations of new energy and play an important role in scenarios such as load peak-valley difference regulation and system black start. At the same time, the fast response characteristics of gas units can match the short-term power fluctuations of new energy, reduce the loss of curtailment of electricity, and improve the inclusiveness of the power system for renewable energy.

[0004] However, the sustainable development of gas power generation faces significant constraints. On the one hand, the external dependence of gas resources is at a relatively high level, and the energy supply security risk is prominent; on the other hand, the energy market price fluctuations have intensified, resulting in high gas power generation costs and insufficient economy for large-scale use as a base load power source. In addition, gas power generation still belongs to the category of carbon-based energy, with a high carbon emission intensity, which is different from the requirements of deep decarbonization of the power source structure under the carbon reduction goal. Therefore, the traditional gas power generation mode is difficult to become the main power source of the new power system, and its development needs to transform towards low-carbon, flexible, and collaborative directions.

[0005] Under this background, the prior art has developed various types of energy complementary integration models. This model organically couples traditional energy units with new energy and energy storage systems to build a coordinated control integrated energy system. However, currently, the benchmark for energy coupling is generally electrical energy coupling. Although this has a fast response speed and is easy to adjust, it is difficult to maintain the long-term system output stability in large fluctuation scenarios; furthermore, the applied electrical energy storage units also have problems such as high cost and short service life, making it difficult for them to be applied on a large scale.

[0006] In summary, it is necessary to integrate and improve the existing power supply units to achieve low-carbon coupling, so as to ensure the stability of the system while effectively controlling the operating costs. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a new energy and gas-electricity coupled low-carbon base load power source with simple system construction implementation, low operating cost, and stable power supply.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides a low-carbon base load power source coupled with new energy and gas-electricity, which mainly includes a new energy power generation field, a molten salt heat storage system, a gas power station, and a power generation system;

[0010] The molten salt heat storage system is a cold and hot tank circulation structure, and the new energy power generation field is connected to the molten salt heat storage system through a first heat exchange unit; the molten salt heat storage system is connected to the power generation system through a second heat exchange unit;

[0011] The gas power station is connected to the power generation system through a third heat exchange unit.

[0012] Optionally, the new energy power generation field includes at least a wind farm;

[0013] The wind farm is connected to the first heat exchange unit through an electric heating system, which is used to convert wind power into heat energy and input it into the molten salt heat storage system;

[0014] The wind farm is also connected to the power grid for grid-connected power generation power compensation.

[0015] Optionally, the new energy power generation field includes a solar thermal power station;

[0016] The heat energy output end of the solar thermal power station is connected to the first heat exchange unit, which is used to input heat energy into the molten salt heat storage system.

[0017] Optionally, the molten salt heat storage system includes a cold molten salt storage tank and a hot molten salt storage tank;

[0018] The cold molten salt storage tank and the hot molten salt storage tank are connected through a circulation loop, and a heat storage loop and a heat release loop are respectively arranged in the circulation loop;

[0019] The first heat exchange unit is connected to the heat storage loop for heat exchange;

[0020] The second heat exchange unit is connected to the heat release loop for heat exchange.

[0021] Optionally, the cold molten salt storage tank and / or the hot molten salt storage tank adopt a multi-tank parallel structure;

[0022] In the molten salt thermal energy storage system, the volumes of the molten salt tanks are not all the same.

[0023] Optionally, the power generation system includes a steam turbine, a generator, and a steam turbine circulation pipeline;

[0024] The steam turbine drives the generator to generate electricity and is connected to the power grid through a power supply circuit;

[0025] Both the second and third heat exchange units are connected to the steam turbine.

[0026] Optionally, a waste heat boiler is provided on the steam turbine circulation pipeline; the second and third heat exchange units are provided on the steam pipeline between the waste heat boiler and the steam turbine.

[0027] Optionally, the second heat exchange unit and the third heat exchange unit are arranged in parallel.

[0028] Optionally, a waste heat recovery device is installed in the flue gas system of the gas power station, and the waste heat recovery device is connected to the third heat exchange unit for inputting the recovered flue gas waste heat into the power generation system.

[0029] Optionally, the gas power station is connected to the power grid through a power supply circuit for direct grid-connected power generation.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The method of the present invention realizes energy conversion and spatio-temporal translation of thermal energy through new energy heat exchange coupling + molten salt thermal energy storage technology, stores excess energy during sufficient sunlight periods, releases thermal energy to drive the steam turbine to generate electricity during low output periods, and forms a stable base load power source; among them, the gas turbine unit serves as a flexible adjustment power source, quickly responds when the new energy output drops suddenly or the load suddenly increases, and makes up for the power gap; the coordinated operation mode not only gives play to the flexibility advantage of gas power generation, but also reduces the dependence on gas resources through new energy substitution, and at the same time realizes the overall carbon emission reduction of the system, meeting the energy development direction of clean, low-carbon, safe and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a system schematic diagram in a specific embodiment of the present invention.

[0034] In the figure: 1. New energy power plant, 2. Molten salt heat storage system, 3. Power generation system, 4. Gas power station, 5. First heat exchange unit, 6. Second heat exchange unit, 7. Third heat exchange unit, 101. Solar thermal power station, 102. Wind farm, 201. Cold molten salt storage tank, 202. Hot molten salt storage tank, 301. Waste heat boiler, 302. Steam turbine, 303. Generator. Detailed implementation mode

[0035] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0037] In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0038] It is worth noting that the methods used in the present invention are all conventional methods unless otherwise specified; the raw materials and devices used are all conventional commercially available products, and their sources are not specifically limited.

[0039] The low-carbon base load power source coupling new energy and gas power provided in this embodiment mainly includes a new energy power plant 1, a molten salt heat storage system 2, a power generation system 3 and a gas power station 4.

[0040] Among them, the new energy power plant 1 is a wind-solar power plant. Taking the solar thermal power station 101 and the wind farm 102 as examples, as Figure 1 shown. The solar thermal power station 101 adjusts the mirror angle in real time to focus solar energy on the vacuum heat collecting tube. After the heat transfer working medium in the heat collecting tube, such as heat transfer oil or molten salt, absorbs heat energy, it is transported to the first heat exchange unit 5 through a pipeline.

[0041] The first heat exchange unit 5 realizes the heat exchange between the solar thermal working medium and the cold molten salt in the molten salt heat storage system 2. The control system of the solar thermal power station 101 integrates a meteorological prediction module, which can automatically adjust the mirror angle to a safe position before the arrival of extreme weather and start the anti-freezing cycle to maintain the fluidity of the working medium through electric tracing.

[0042] The single-unit capacity of the wind farm 102 is selected according to the site conditions. The wind turbine realizes variable-speed constant-frequency power generation through a full-power converter. A part of the output electric energy can be directly connected to the grid, and the other part can drive the electric heating system after being converted into industrial frequency by a high-voltage frequency converter. Thus, when the power demand is large or the light intensity is low, the wind power can be directly connected to the grid to provide clean power, thereby compensating for the missing generated power; when the power demand is small or the light intensity is high, the wind power can be converted into heat energy and stored in the molten salt thermal energy storage system. The electric heating system uses resistive or inductive heating elements to convert electric energy into heat energy, and transports the heated working medium to the first heat exchange unit 5 through a working medium circulation pump for secondary heat exchange with the cold molten salt. The power distribution of the wind farm 102 is dynamically adjusted by an intelligent control system according to the grid load, light intensity and thermal energy storage state, and the "grid-connected power generation" and "thermal energy storage power supply" modes are quickly switched through a power electronic switch matrix.

[0043] The molten salt thermal energy storage system 2 adopts a double-tank circulation structure. When the load of the power system is large, the molten salt thermal energy storage system releases heat to drive the steam turbine to generate electricity; when the load is small, the molten salt thermal energy storage system stores thermal energy. Among them, the cold molten salt storage tank 201 and the hot molten salt storage tank 202 are connected by a molten salt circulation pump group. On the heat storage loop, the first heat exchange unit 5 transfers the heat generated by solar thermal and wind power to the cold molten salt, and stores it in the hot molten salt storage tank 202 after its temperature rises. On the heat release loop, the hot molten salt exchanges heat with water through the second heat exchange unit 6 to generate high-temperature and high-pressure steam to drive the power generation system 3. The second heat exchange unit 6 realizes countercurrent heat exchange between the molten salt and water to improve the thermal efficiency. The third heat exchange unit 7 is connected in series with the waste heat recovery device of the gas power station 4 to further recover the waste heat of the flue gas and improve the overall energy efficiency of the system.

[0044] In another embodiment, the cold molten salt storage tank 201 and the hot molten salt storage tank 202 can adopt a multi-tank parallel structure according to the energy storage demand, and the pressure balance of each tank body is realized through a balance pipe. The tank body is equipped with an independent temperature sensor array and a radar level gauge to monitor the molten salt state in real time. For large-fluctuation scenarios, the system adopts a stepped volume ratio design, and the total volume of the cold tanks is larger than the total volume of the hot tanks to cope with the intermittency of new energy output.

[0045] The power generation system 3 is a reheating steam turbine generator set, which includes a steam turbine 302, a generator 303 and a steam turbine circulation pipeline. The steam turbine 302 drives the generator 303 to generate electricity and is connected to the power grid through a power supply circuit. The main steam parameters of the power generation system 3 are determined according to the system design. The steam turbine circulation pipeline adopts a three-stage regenerative system, including high-pressure heaters, deaerators and low-pressure heaters, to improve the system efficiency through feedwater regeneration. The waste heat boiler 301 is used as an auxiliary heat source and is connected in parallel with the main steam pipeline through a four-way reversing valve. When the molten salt energy storage system 2 supplies energy alone, the waste heat boiler 301 is in a standby state; when it is necessary to quickly increase the load, the waste heat boiler 301 can also introduce the flue gas waste heat of the gas power station 4 to supplement the steam volume. The steam turbine 302 is equipped with a digital electro-hydraulic control system to achieve precise speed and load regulation, and the load response rate meets the peak shaving requirements of the power grid.

[0046] The gas power station 4 is also connected to the power grid through a power supply circuit and is used for direct grid-connected power generation. Its compressor adopts an axial-flow multi-stage design, and a filter separator is configured at the inlet to prevent dust particles from entering the system. The combustion chamber supports the co-firing of natural gas and hydrogen, and the fuel components are monitored in real time through a laser spectroscopy on-line analysis system. The flue gas waste heat recovery device adopts a triple-pressure reheat system to recover the heat of high-temperature, medium-temperature and low-temperature flue gas in sequence to generate steam with different parameters. The waste heat boiler 301 is connected to the gas turbine exhaust system through a flue. After the flue gas passes through multi-stage heat exchange, it is finally treated environmentally to ensure that the pollutant emissions meet the standards.

[0047] The energy management system integrated in the system adopts a hierarchical distributed control architecture. The field control layer realizes device-level control through PLCs. The coordination layer generates a scheduling plan based on a model predictive control algorithm. The optimization layer takes the lowest system operation cost as the objective function to solve the optimal energy distribution scheme. The multi-source collaborative operation strategy includes a solar thermal priority mode, a heat storage energy release mode and an extreme weather mode. In the solar thermal priority mode, the solar thermal power station 101 supplies energy in full, and the wind farm 102 is only grid-connected during peak loads, and the surplus power is used for heat storage; in the heat storage energy release mode, the system relies on the molten salt energy storage system 2 to supply power, and the gas power station 4 is in a hot standby state; in the extreme weather mode, the system switches to the "gas power base load + heat storage peak shaving" mode to ensure power supply reliability.

[0048] Through the above technical optimizations, the system realizes the deep coupling of solar thermal - wind power - gas power - heat storage. While maintaining flexibility and stability, it significantly improves the comprehensive energy utilization rate and low-carbon performance. The system can flexibly switch between base load power generation and peak shaving modes according to the power grid demand, providing reliable support for a high-proportion new energy power system and promoting the transformation of the energy structure towards clean and low-carbon.

[0049] In the embodiments of the present invention, a new low-carbon base-load power supply scheme is designed, which innovatively couples a gas power station with a solar thermal power station and a wind farm, enabling multi-energy coupling and integrated optimal scheduling of the "gas power + new energy" unit combination. Specifically, as follows:

[0050] (1) The wind farm is connected to the solar thermal power station through a heat exchanger, providing energy for the molten salt energy storage system according to the light conditions, or directly connecting to the grid for power generation according to the electricity demand of the power system.

[0051] (2) The gas power station shares the power generation system with the solar thermal power station, recovering the waste heat of the internal combustion engine flue gas through a heat exchanger, improving the overall efficiency of the energy supply system, realizing multi-level utilization of energy, and at the same time providing guaranteed power supply according to the electricity demand of the system to make up for the instability of the output of solar thermal and wind power.

[0052] Comparative Example 1;

[0053] Consider replacing a 600 MW gas power station in a certain area with the new low-carbon base-load power supply scheme in the foregoing embodiments, that is, replacing the pure gas power scheme of a 420 MW gas turbine and a 180 MW steam turbine with a "gas power + new energy" installed capacity configuration of a 300 MW gas turbine, a 200 MW steam turbine, 600 MW of wind power, 200 MW of solar thermal, and 1600 MWh of molten salt energy storage with the same output level. The comparison results are shown in Table 1 below:

[0054] Table 1

[0055]

[0056] Draw the following conclusions based on the above table:

[0057] From the perspective of economy, in terms of the cost per kilowatt-hour of electricity, the cost per kilowatt-hour of electricity in this embodiment is 0.36 yuan / kWh, which is the same as that of the original scheme.

[0058] In terms of fuel cost, the natural gas consumption of the scheme in this embodiment is 221 million cubic meters, which is about 30% of the natural gas consumption of the original scheme 1. The fuel cost of the new low-carbon base-load power supply scheme in this embodiment is significantly lower than that of the pure gas power scheme.

[0059] From the perspective of the reliability of power supply, the expected value of insufficient electricity EENS (the expected value of the electricity volume that cannot supply power to the load within one year) of the scheme in this embodiment is 4862 MWh / year, and the proportion of EENS in the theoretical output of the system is about 0.1%. The system operation stability of the new low-carbon base-load power supply scheme is relatively high.

[0060] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement made by those of ordinary skill in the art to the technical solution of the present invention shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A low-carbon base load power source coupling new energy and gas-electricity, characterized in that: It includes a new energy power plant, a molten salt thermal energy storage system, a gas power station and a power generation system; The molten salt thermal energy storage system is a cold and hot tank circulation structure. The new energy power plant is connected to the molten salt thermal energy storage system through a first heat exchange unit; the molten salt thermal energy storage system is connected to the power generation system through a second heat exchange unit; The gas power station is connected to the power generation system through a third heat exchange unit.

2. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 1, wherein: The new energy power plant at least includes a wind farm; The wind farm is connected to the first heat exchange unit through an electric heating system, which is used to convert wind power into heat energy and input it into the molten salt thermal energy storage system; The wind farm is also connected to the power grid for grid-connected power generation compensation.

3. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 1 or 2, characterized in that: The new energy power plant includes a solar thermal power station; The heat energy output end of the solar thermal power station is connected to the first heat exchange unit, which is used to input heat energy into the molten salt thermal energy storage system.

4. The low-carbon base load power source with new energy and gas-electricity coupling according to claim 1, characterized in that: The molten salt thermal energy storage system includes a cold molten salt storage tank and a hot molten salt storage tank; The cold molten salt storage tank is connected to the hot molten salt storage tank through a circulation loop, and a heat storage loop and a heat release loop are respectively arranged in the circulation loop; The first heat exchange unit is connected to the heat storage loop for heat exchange; The second heat exchange unit is connected to the heat release loop for heat exchange.

5. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 4, characterized in that: The cold molten salt storage tank and / or the hot molten salt storage tank adopt a structure of multiple tanks in parallel; In the molten salt thermal energy storage system, the volumes of the molten salt tanks are not all the same.

6. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 1, characterized in that: The power generation system includes a steam turbine, a generator and a steam turbine circulation pipeline; The steam turbine drives the generator to generate electricity and is connected to the power grid through a power supply circuit; Both the second and third heat exchange units are connected to the steam turbine.

7. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 6, characterized in that: A waste heat boiler is arranged on the steam turbine circulation pipeline; the second and third heat exchange units are arranged on the steam pipeline between the waste heat boiler and the steam turbine.

8. The low-carbon base load power source for new energy and gas-electricity coupling according to claim 7, characterized in that: The second heat exchange unit and the third heat exchange unit are arranged in parallel.

9. The low-carbon base load power source for coupling new energy and gas-electricity according to claim 1, characterized in that: A waste heat recovery device is installed in the flue gas system of the gas power station, and the waste heat recovery device is connected to the third heat exchange unit, which is used to input the recovered flue gas waste heat into the power generation system.

10. The low-carbon base load power source with new energy and gas-electricity coupling according to claim 1 or 9, characterized in that: The gas power station is connected to the power grid through a power supply circuit for direct grid-connected power generation.

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