User side compressed air energy storage system

Abstract

The utility model provides a user side compressed air energy storage system which can be used in the technical field of compressed air energy storage. The user side compressed air energy storage system comprises an air compression system used for compressing raw material air; the secondary pressurization system is used for pressurizing the compressed air conveyed by the air compression system again; the heat storage and heat exchange system is used for collecting and storing compression heat generated when the air is pressurized by the second-stage pressurization system; the high-pressure air storage system is used for storing the high-pressure air conveyed by the secondary pressurization system; the expansion power generation system is used for heating the high-pressure air stored in the high-pressure air storage system by using the compression heat stored in the heat storage and heat exchange system, driving an air expansion power generator to generate power by using the heated high-pressure air, and introducing compressed air at an outlet of the air expansion power generator into a compressed air pipeline; and the compressed air pipeline is used for conveying the compressed air conveyed by the air compression system and the expansion power generation system to air utilization equipment.

Description

Technical Field

[0001] The present application relates to the technical field of compressed air energy storage, and in particular to a user-side compressed air energy storage system. Background Art

[0002] Compressed air is one of the most widely used power sources in the industrial field. It is widely used in the metallurgical field because of its many advantages such as safety, environmental protection, good regulation performance and convenient transportation. In various processes of steel production, such as raw materials, ironmaking, steelmaking, and steel rolling, whether it is instrument valve control, equipment purging, pneumatic equipment drive or pneumatic transportation, compressed air is needed. The compressed air station is a production unit of compressed air and an indispensable energy supply unit in steel production enterprises. The demand for compressed air in steel enterprises is large, and the use of compressed air in large steel enterprises can reach 120,000-200,000 m3 / h. The steel industry is a large electricity user, and its annual electricity consumption accounts for more than 9.4% of the total power generation. Among them, the compressed air system is one of the main electricity users of steel enterprises, accounting for 15% to 30% of the total energy consumption of the entire factory, which consumes a lot of energy. At the same time, due to overcapacity and other reasons, the current steel enterprises often have a mismatch between the designed gas volume of the compressor and the actual compressed air consumption, resulting in idle equipment, excessive land occupation and high maintenance costs.

[0003] In response to the above problems, there is a device system and gas supply method for coupling compressed air energy storage and gas supply in the prior art, which records: coupling compressed air energy storage and gas supply can store low-cost valley electricity and reduce the electricity cost of steel plants, and the compressed air generated by the compressed air energy storage system is applied to various process areas of the steel plant to meet their demand for compressed air, which greatly improves the economy of the steel plant operation and has a prospect for large-scale promotion and application.

[0004] The technology states that it is obviously unrealistic to use only the existing compressors of steel enterprises to compress the air during the energy storage stage without adding additional compressors. Since the existing compressors are designed to operate in a single unit and supply air in parallel, it is impossible to realize the multi-stage pressurization process of compressors in series. If the compressed air is only compressed to 1.5mPa instead of a high-pressure state, the volume of the gas storage device will increase significantly and the cost will increase significantly.

[0005] The compressed air supply method described in this technology is to extract compressed air in stages according to the pressure level required by the compressed air user. There are two main methods for compressed air supply in steel enterprises, centralized supply and decentralized supply. For decentralized supply scenarios, this air supply method can be used, but due to the small amount of decentralized supply, the energy storage efficiency will be greatly reduced. At present, centralized supply of compressed air is the trend of air compression systems in steel enterprises, and the centralized supply of gas is large. The generated compressed air is uniformly incorporated into the 0.6-0.8mPa compressed air pipeline network and then distributed to each user point. Therefore, this method is not applicable.

[0006] This technology does not consider the use of a large amount of waste heat resources from steel companies. Since compressed air energy storage technology involves the conversion of multiple energy forms, the waste heat from steel companies can be applied to the compressed air energy storage system to improve the overall efficiency of the system.

[0007] In addition, there is also a coupled operation system of compressed air energy storage and power station boiler in the prior art, including compression-cooling equipment, normal temperature gas storage equipment, power station boiler and heat recovery-expansion working equipment; the compression-cooling equipment includes an air compressor unit and a boiler air inlet heater; the heat recovery-expansion working equipment includes a boiler tail gas waste heat recovery device and an air turbine generator set; the boiler air inlet heater fully exchanges the compressed air generated by the air compressor unit with the boiler air inlet and then introduces it into the normal temperature gas storage equipment, and introduces the heated boiler air inlet into the power station boiler to participate in combustion; the boiler tail gas waste heat recovery device recovers the waste heat in the boiler tail gas to heat the normal temperature compressed air derived from the normal temperature gas storage equipment; the heated compressed air is introduced into the air turbine generator set for power generation. Through this system, the problem of energy loss caused by compressed air energy storage and boiler operation can be effectively solved.

[0008] However, the above system does not reasonably reuse the compressed air generated in the compressed air energy storage process, which causes energy waste to a certain extent, and does not consider the use of existing equipment of the coupling object. Utility Model Content

[0009] In response to the problems in the prior art, an embodiment of the present application provides a user-side compressed air energy storage system that can at least partially solve the problems in the prior art.

[0010] The embodiment of the present application provides a user-side compressed air energy storage system, comprising:

[0011] The air compression system compresses the raw air and delivers the generated compressed air to the compressed air pipeline and the secondary pressurization system;

[0012] A secondary pressurizing system, connected to the air compression system, re-pressurizes the compressed air delivered by the air compression system and then delivers it to the high-pressure gas storage system;

[0013] A heat storage and heat exchange system, connected to the secondary pressurization system, collects and stores compression heat generated by the secondary pressurization system when pressurizing air;

[0014] A high-pressure gas storage system, connected to the secondary pressurization system, storing the high-pressure air delivered by the secondary pressurization system;

[0015] an expansion power generation system connected to the heat storage and heat exchange system and the high-pressure gas storage system, using the compression heat stored in the heat storage and heat exchange system to heat the high-pressure air stored in the high-pressure gas storage system, using the heated high-pressure air to drive the air expansion generator to generate electricity, and introducing the compressed air at the outlet of the air expansion generator into the compressed air pipeline;

[0016] The compressed air pipeline is connected to the air compression system and the expansion power generation system to deliver the compressed air delivered by the air compression system and the expansion power generation system to the gas-consuming equipment.

[0017] In some embodiments, the air compression system includes at least one air compression mechanism, each of which includes an air filter, an air compressor unit and a reheat air dryer connected in sequence; wherein the reheat air dryer of each air compression mechanism is connected to the compressed air pipeline and the secondary pressurization system through a pipeline.

[0018] In some embodiments, the secondary pressurization system includes at least one pressurization mechanism, each of which includes a centrifugal air compressor group and a compressed air bypass with a flow regulating valve connected to the centrifugal air compressor group; wherein the centrifugal air compressor group of each pressurization mechanism is connected to the air compression system, and the compressed air bypass with a flow regulating valve is connected to the high-pressure air storage system.

[0019] In some embodiments, the heat storage and heat exchange system includes at least one heat storage mechanism. Each of the heat storage mechanisms includes a tubular heat exchanger, a steam-water separation heat exchanger, a cold water storage tank, a hot water storage tank, and a circulation pump; wherein,

[0020] The tubular heat exchanger is connected to the centrifugal air compressor unit, the cold water storage tank, and the hot water storage tank respectively. The circulating pump is installed on the circulation loop formed by the tubular heat exchanger, the cold water storage tank, and the hot water storage tank. The steam-water separation heat exchanger is installed between the centrifugal air compressor unit and the compressed air bypass with a flow regulating valve.

[0021] In some embodiments, the heat storage medium in the tubular heat exchanger, the cold water storage tank, and the hot water storage tank includes pressurized water, thermal oil, or molten salt.

[0022] In some embodiments, the high-pressure gas storage system includes a compressed air storage reservoir, which is connected to the secondary pressurization system and the expansion power generation system.

[0023] In some embodiments, the expansion power generation system includes a tubular heat exchanger, a waste heat exchanger and an air expansion generator connected in sequence, the tubular heat exchanger is also connected to the heat storage and heat exchange system, the waste heat exchanger is also connected to an external waste heat resource, and the air expansion generator is also connected to the compressed air pipeline.

[0024] In some embodiments, during the off-peak period of electricity consumption, the air compression system compresses the raw air and delivers part of the compressed air to the compressed air pipeline, and introduces the other part of the compressed air into the secondary pressurization system, and the secondary pressurization system compresses the compressed air again to obtain high-pressure air and delivers the high-pressure air to the high-pressure air storage system for storage; in the above process, the heat storage and heat exchange system is used to recover the compression heat of each stage through the heat exchanger and store it in the heat storage medium;

[0025] During peak electricity consumption, high-pressure air is drawn out from the high-pressure gas storage system and preheated using the compression heat stored in the heat storage medium. At the same time, external waste heat resources can be used to reheat the high-pressure air. The reheated high-pressure air drives the generator in the expansion power generation system to generate electricity, and the air output from the expansion power generation system outlet is incorporated into the compressed air pipeline for gas supply.

[0026] In some embodiments, during the period of low electricity consumption, all air compressor units in the air compression system are operated at full load. When each air compression mechanism is working, the raw air is sucked into the air filter of the air compression mechanism through the first pipe, and then enters the air compressor unit through the second pipe. The second pipe is provided with a first flow regulating valve; the compressed air enters the reheat air dryer through the third pipe, and the dry and purified compressed air output by the reheat air dryer is collected in the compressed air pipeline. The second flow regulating valve provided on the compressed air pipeline controls a part of the compressed air to enter the compressed air pipeline, and the other part enters the secondary pressurization system.

[0027] In some embodiments, during peak electricity consumption, high-pressure air is introduced from the high-pressure gas storage system into the expansion power generation system, and the flow rate of high-pressure air entering the expansion power generation system is controlled by a flow regulating valve, and the pressure of high-pressure air entering the expansion power generation system is controlled by a throttle valve. The high-pressure air is preheated in a tubular heat exchanger using the compression heat stored in the heat storage medium, and then enters a waste heat heat exchanger to reheat the high-pressure air using external waste heat resources, and then enters an air expansion generator to drive the generator to generate electricity, and then controls the air pressure at the outlet of the air expansion generator to be incorporated into the compressed air pipeline for air supply. If the air supply meets the gas demand at this time, the air compression system can be unloaded. If the air supply is not enough to meet the gas demand at this time, some air compressor units of the air compression system can be unloaded or operated at low load.

[0028] The user-side compressed air energy storage system provided by the embodiment of the present application, during the off-peak period of electricity consumption, the air compression system compresses the raw air and delivers part of the compressed air to the compressed air pipeline, and introduces the other part of the compressed air into the secondary pressurization system, and the secondary pressurization system compresses the compressed air again to obtain high-pressure air and delivers the high-pressure air to the high-pressure gas storage system for storage; in the above process, the heat storage and heat exchange system is used to recover the compression heat of each level through the heat exchanger and store it in the heat storage medium; during the peak period of electricity consumption, the high-pressure air is drawn out from the high-pressure gas storage system, and the high-pressure air is preheated by the compression heat stored in the heat storage medium, and the high-pressure air can be reheated by external waste heat resources. The reheated high-pressure air drives the generator in the expansion power generation system to generate electricity, and the air output from the outlet of the expansion power generation system is incorporated into the compressed air pipeline for gas supply. In this way, the load of the air compression system of the steel enterprise during the peak period of electricity consumption can be transferred to the off-peak period of electricity consumption. While ensuring continuous air supply, high-pressure air expansion power generation and the utilization of waste heat resources of the steel enterprise can also be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0030] Figure 1 It is a structural schematic diagram of a user-side compressed air energy storage system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Here, the illustrative embodiments of the present application and their descriptions are used to explain the present application, but are not intended to limit the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily arranged with each other.

[0032] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit this application. They are only used to distinguish elements or operations described with the same technical terms.

[0033] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0034] As used herein, "and / or" includes any and all permutations of the items described.

[0035] In order to better understand the present application, the research background of the present application is briefly introduced below.

[0036] The compressed air energy storage system uses compressed air as an energy storage carrier. It is a physical energy storage technology that uses mechanical equipment to achieve energy storage and cross-time, space transfer and utilization. In the energy storage stage, by utilizing excess or non-peak electric energy, the motor drives the multi-stage compressor to compress the air to high pressure and store it in the gas storage system. During the process, the compression heat of each stage is recovered through the heat exchanger and stored in the heat storage medium, completing the conversion of excess electric energy to air potential energy. In the energy release stage, the compressed air is drawn out of the gas storage system, and the multi-stage air turbine expander is used to do work to drive the generator to generate electricity. During the process, the compression heat stored in the heat storage medium is used to heat the expanded air, improve its work capacity, and complete the conversion of air potential energy to peak electric energy. At present, the theoretical efficiency of the compressed air energy storage system can reach 70%, but in actual operation, the actual efficiency is low due to the insufficient utilization of compression waste heat. Since compressed air energy storage technology has multiple energy form conversions, it can be coupled with other energy systems to form an energy hub station, thereby achieving complementary advantages, further improving the operating efficiency of the energy storage system, and also improving the utilization rate of the coupled energy.

[0037] Figure 1 is a schematic diagram of the structure of a user-side compressed air energy storage system provided in an embodiment of the present application, such as Figure 1 As shown, the user-side compressed air energy storage system provided in the embodiment of the present application includes:

[0038] The air compression system 1 compresses the raw air and delivers the generated compressed air to the compressed air pipeline 6 and the secondary pressurization system 2;

[0039] A secondary pressurizing system 2, connected to the air compression system 1, re-pressurizes the compressed air delivered by the air compression system 1 and then delivers it to the high-pressure gas storage system 4;

[0040] The heat storage and heat exchange system 3 is connected to the secondary pressurizing system 2 to collect and store the compression heat generated by the secondary pressurizing system 2 when pressurizing the air;

[0041] A high-pressure gas storage system 4, connected to the secondary pressurizing system 2, storing the high-pressure air delivered by the secondary pressurizing system 2;

[0042] The expansion power generation system 5 is connected to the heat storage and heat exchange system 3 and the high-pressure gas storage system 4, and uses the compression heat stored in the heat storage and heat exchange system 3 to heat the high-pressure air stored in the high-pressure gas storage system 4, and uses the heated high-pressure air to drive the air expansion generator 53 to generate electricity, and introduces the compressed air at the outlet of the air expansion generator 53 into the compressed air pipeline 6;

[0043] The compressed air pipeline 6 is connected to the air compression system 1 and the expansion power generation system 5 to deliver the compressed air delivered by the air compression system 1 and the expansion power generation system 5 to the gas-consuming equipment.

[0044] The user-side compressed air energy storage system provided in the embodiment of the present application, during the off-peak period of electricity consumption, the air compression system 1 compresses the raw air and delivers part of the compressed air to the compressed air pipeline 6, and introduces the other part of the compressed air into the secondary pressurization system 2, and the secondary pressurization system 2 compresses the compressed air again to obtain high-pressure air and delivers the high-pressure air to the high-pressure gas storage system 4 for storage; in the above process, the heat storage and heat exchange system 3 is used to recover the compression heat of each level through the heat exchanger and store it in the heat storage medium; during the peak period of electricity consumption, the high-pressure air is drawn out from the high-pressure gas storage system 4, and the high-pressure air is preheated by the compression heat stored in the heat storage medium, and the high-pressure air can be reheated by external waste heat resources. The reheated high-pressure air drives the generator in the expansion power generation system 5 to generate electricity, and the air output from the outlet of the expansion power generation system 5 is merged into the compressed air pipeline 6 for gas supply. In this way, the load of the air compression system 1 of the steel enterprise during the peak period of electricity consumption can be transferred to the off-peak period of electricity consumption. Under the condition of ensuring continuous air supply, high-pressure air expansion power generation and the utilization of waste heat resources of the steel enterprise can also be realized.

[0045] like Figure 1 As shown, in some embodiments, the air compression system 1 includes at least one air compression mechanism, each of which includes an air filter 11, an air compressor unit 12 and a reheat air dryer 13 connected in sequence; wherein the reheat air dryer 13 of each air compression mechanism is connected to the compressed air pipeline 6 and the secondary pressurization system 2 through a pipeline.

[0046] like Figure 1 As shown, in some embodiments, the secondary pressurizing system 2 includes at least one pressurizing mechanism, each pressurizing mechanism includes a centrifugal air compressor group 21 and a compressed air bypass 22 with a flow regulating valve connected to the centrifugal air compressor group 21; wherein the centrifugal air compressor group 21 of each pressurizing mechanism is connected to the air compression system 1, and the compressed air bypass 22 with a flow regulating valve is connected to the high-pressure air storage system 4.

[0047] like Figure 1 As shown, the heat storage and heat exchange system 3 includes at least one heat storage mechanism. Each of the heat storage mechanisms includes a tubular heat exchanger 51, a steam-water separation heat exchanger 32, a cold water storage tank 33, a hot water storage tank 34 and a circulation pump 35; wherein,

[0048] The tubular heat exchanger 51 is connected to the centrifugal air compressor unit 21, the cold water storage tank 33, and the hot water storage tank 34 respectively. The circulating pump 35 is installed on the circulation loop formed by the tubular heat exchanger 51, the cold water storage tank 33 and the hot water storage tank 34. The steam-water separation heat exchanger 32 is installed between the centrifugal air compressor unit 21 and the compressed air bypass 22 with a flow regulating valve.

[0049] like Figure 1 As shown, in some embodiments, the heat storage medium in the tubular heat exchanger 51, the cold water storage tank 33 and the hot water storage tank 34 includes pressurized water, thermal oil or molten salt.

[0050] like Figure 1 As shown, in some embodiments, the high-pressure gas storage system 4 includes a compressed air storage reservoir 41 , and the compressed air storage reservoir 41 is connected to the secondary pressurization system 2 and the expansion power generation system 5 .

[0051] like Figure 1 As shown, in some embodiments, the expansion power generation system 5 includes a tubular heat exchanger 51, a waste heat exchanger 52 and an air expansion generator 53 connected in sequence, the tubular heat exchanger 51 is also connected to the heat storage and heat exchange system 3, the waste heat exchanger 52 is also connected to an external waste heat resource, and the air expansion generator 53 is also connected to the compressed air pipeline 6.

[0052] like Figure 1As shown, in some embodiments, during the low electricity consumption period, the air compression system 1 compresses the raw air and delivers part of the compressed air to the compressed air pipeline 6, and introduces the other part of the compressed air into the secondary pressurizing system 2, and the secondary pressurizing system 2 compresses the compressed air again to obtain high-pressure air and delivers the high-pressure air to the high-pressure air storage system 4 for storage; in the above process, the heat storage and heat exchange system 3 is used to recover the compression heat of each stage through the heat exchanger and store it in the heat storage medium;

[0053] During peak electricity consumption, high-pressure air is drawn out from the high-pressure gas storage system 4, and the high-pressure air is preheated using the compression heat stored in the heat storage medium. At the same time, the high-pressure air can be reheated using external waste heat resources. The reheated high-pressure air drives the generator in the expansion power generation system 5 to generate electricity, and the air output from the outlet of the expansion power generation system 5 is incorporated into the compressed air pipeline 6 for air supply.

[0054] like Figure 1 As shown, in some embodiments, the air compression system 1 includes at least one air compression mechanism, each of which includes an air filter 11, an air compressor unit 12 and a reheat air dryer 13 connected in sequence, wherein the reheat air dryer 13 of each air compression mechanism is connected to the compressed air pipeline 6 and the secondary pressurization system 2 through a pipeline,

[0055] During the low electricity consumption period, all the air compressor units 12 in the air compression system 1 are operated at full load. When each of the air compression mechanisms is working, the raw air is sucked into the air filter 11 of the air compression mechanism through the first pipeline, and then enters the air compressor unit 12 through the second pipeline. The second pipeline is provided with a first flow regulating valve; the compressed air enters the reheat air dryer 13 through the third pipeline, and the dry and purified compressed air output by the reheat air dryer 13 is collected in the compressed air pipeline. A part of the compressed air is controlled to enter the compressed air pipeline 6 through the second flow regulating valve provided on the compressed air pipeline, and the other part enters the secondary pressurization system 2.

[0056] like Figure 1 As shown, in some embodiments, the expansion power generation system 5 includes a tubular heat exchanger 51, a waste heat exchanger 52 and an air expansion generator 53 connected in sequence, the tubular heat exchanger 51 is also connected to the heat storage and heat exchange system 3, the waste heat exchanger 52 is also connected to an external waste heat resource, and the air expansion generator 53 is also connected to the compressed air pipeline 6.

[0057] During peak electricity consumption, high-pressure air is introduced from the high-pressure gas storage system 4 into the expansion power generation system 5. The flow rate of high-pressure air entering the expansion power generation system 5 is controlled by a flow regulating valve, and the pressure of high-pressure air entering the expansion power generation system 5 is controlled by a throttle valve. The high-pressure air is preheated in the tubular heat exchanger 51 using the compression heat stored in the heat storage medium, and then enters the waste heat heat exchanger 52, where the high-pressure air is reheated using external waste heat resources, and then enters the air expansion generator 53 to drive the generator to generate electricity. The air pressure at the outlet of the air expansion generator 53 is then controlled to be incorporated into the compressed air pipeline 6 for air supply. If the air supply meets the gas demand at this time, the air compression system 1 can be unloaded. If the air supply is not enough to meet the gas demand at this time, part of the air compressor unit 12 of the air compression system 1 can be unloaded or operated at a low load.

[0058] In order to better understand the present application, the user-side compressed air energy storage system provided by the present application is described in detail below through a specific embodiment.

[0059] The embodiment of the present application provides a compressed air energy storage hub system for a steel enterprise, which is mainly transformed into a comprehensive energy hub system that can realize the cogeneration of gas, electricity, and cold / heat for steel enterprises by comprehensively considering the coupling of the existing air compressor station system of the steel enterprise with the compressed air energy storage system. During the low electricity consumption period, the original air compressor system 1 of the steel enterprise serves as the first-stage compression system of the compressed air energy storage system. While ensuring the amount of compressed air used in the factory, the remaining compressed air is introduced into the secondary pressurization system 2. The secondary pressurization system 2 uses excess or non-peak electricity to drive a multi-stage compressor through an electric motor to compress the air to high pressure and store it in the high-pressure gas storage system 4. During the process, the compression heat of each stage is recovered through a heat exchanger and stored in a heat storage medium. During the peak electricity consumption period, the compressed air is drawn out from the high-pressure gas storage system 4, and the compressed air is preheated using the compression heat stored in the heat storage medium. At the same time, the waste heat resources of the steel enterprise can be used to reheat the compressed air to fully improve its working capacity. High-temperature and high-pressure air is used to perform work through a multi-stage air turbine expander with back pressure, driving a generator to generate electricity, and then the air pressure at the expander outlet is controlled to be incorporated into the compressed air pipeline 6 for air supply, thereby replacing the original air compressor unit of the steel enterprise during peak hours. This application can transfer the load of the steel enterprise's air compression system 1 during peak electricity consumption to the off-peak electricity consumption period through a compressed air energy storage system. While ensuring continuous air supply, it can also realize high-pressure air expansion power generation and the utilization of waste heat resources of the steel enterprise.

[0060] Figure 1 is a structural diagram of a compressed air energy storage system for a steel enterprise provided in an embodiment of the present application, such as Figure 1As shown, the system includes at least one set of steel enterprise air compression system 1, at least one set of secondary pressurization system 2, at least one set of heat storage and heat exchange system 3, at least one set of high-pressure gas storage system 4, at least one set of expansion power generation system 5, and at least one set of compressed air pipeline 6, and each system is connected through the compressed air pipeline 6. Among them, the steel enterprise air compression system 1 includes at least one set of air filter 11, at least one set of air compressor unit 12, and at least one set of reheat air dryer 13. During the low electricity consumption period, all the air compressor units 12 in the steel enterprise air compression system 1 are fully loaded, and the raw air is sucked into the self-cleaning air filter 11 through the pipeline, and then enters the air compressor unit 12 through the pipeline, and a flow regulating valve is provided on the pipeline; the compressed air enters the air dryer 13 through the pipeline, becomes dry and purified compressed air and is collected in the compressed air pipeline 6, and a part of the compressed air is controlled by the flow regulating valve to enter the compressed air pipeline 6 to ensure the gas for steel production during the low electricity consumption period, and the other part enters the secondary pressurization system 2, and a flow meter is provided on each branch. The secondary pressurization system 2 includes at least one centrifugal air compressor unit 21 and at least one compressed air bypass 22 with a flow control valve; the heat storage and heat exchange system 3 includes at least one tubular heat exchanger 31, at least one steam-water separation heat exchanger 32, a cold water storage tank 33, a hot water storage tank 34, and two circulating pumps 35. The heat storage medium can be but is not limited to pressurized water, heat transfer oil or molten salt; the compressed air passing through the air compression system 1 of the steel enterprise enters the secondary pressurization system 2 through a pipeline for multi-stage compression to increase its temperature and pressure. The high-temperature compressed air in the tubular heat exchanger 31 between stages is stored in the circulating heat storage medium of the cold water storage tank 33 to recover the compression heat generated during the compression process. The heat storage medium after heat exchange enters the hot water storage tank 34, and the heat storage medium circulates in the cold and hot water storage tanks 34 through the circulating pump 35. The compressed air after heat exchange enters the steam-water separation heat exchanger 32 through a pipeline, and after the remaining water is removed, it becomes pure compressed air at room temperature and high pressure and enters the high-pressure gas storage system 4 for storage, wherein the high-pressure gas storage system 4 at least includes a compressed air storage reservoir 41, and can be but not limited to natural salt caverns, artificial chambers, pipeline steel gas storage reservoirs or a combination of multiple gas storage methods. The high-pressure gas storage system 4 is connected to the secondary pressurization system 2 and the expansion power generation system 5 through a pipeline, and a flow regulating valve is provided on the pipeline.

[0061] The expansion power generation system 5 includes at least one tubular heat exchanger 51 , one waste heat exchanger 52 , and one air expansion generator 53 with back pressure. During the peak period of electricity consumption, compressed air is introduced from the high-pressure gas storage system 4 into the expansion power generation system 5, and the flow rate of compressed air entering the expansion power generation system 5 is controlled by a flow regulating valve, and the pressure of compressed air entering the expansion power generation system 5 is controlled by a throttle valve. The high-pressure compressed air is preheated in the tubular heat exchanger 51 using the compression heat stored in the heat storage medium, and then enters the waste heat heat exchanger 52, and the compressed air is reheated using the waste heat resources of the steel enterprise to fully improve its working capacity. Then, it enters the expansion generator set 53 for multi-stage expansion and power generation, and work is performed by a multi-stage air turbine expander with back pressure to drive the generator to generate electricity, and then the air pressure at the expander outlet is controlled to be merged into the compressed air pipeline 6 for air supply. If the air supply at this time meets the gas demand of the steel enterprise during the peak period, the air compression system 1 of the steel enterprise can be unloaded; if the air supply at this time is not enough to meet the gas demand of the steel enterprise during the peak period, some compressor units of the air compression system 1 of the steel enterprise can be unloaded or operated at a low load.

[0062] Among them, the compressed air bypass 22 can adjust the gas storage pressure and flow at any time to adapt to the fluctuation of the compressed air demand of the steel enterprise.

[0063] The embodiment of the present application couples the air compression system 1 of the steel enterprise with the compressed air energy storage system. The coupling system can not only continuously supply air to the compressed air network of the steel enterprise, but also convert electrical energy into compressed air potential energy during the low electricity consumption period, and convert compressed air potential energy into peak power supply during the peak electricity consumption period. At the same time, it can supply air to the compressed air network, greatly improving energy utilization and system efficiency.

[0064] This embodiment includes 2 sets of steel enterprise air compressor units, 1 set of two-stage pressurization system 2, 1 set of heat storage and heat exchange system 3, a set of high-pressure gas storage system 4 and 1 set of expansion power generation system 5. However, the number of each system is not necessarily fixed, and can be flexibly adjusted according to production needs. There may be more than 2 sets of steel enterprise air compressor units; three or more pressurization systems may also be required; the heat storage and exchange medium is not limited to pressurized water, and may also be circulating heat transfer oil or molten salt, etc.; there may also be multiple sections or multiple sets of expansion power generation systems 5. Without departing from the concept of this application, various changes and modifications should all fall within the scope of protection of this application.

[0065] In this application, the compressed air main pipe (i.e., compressed air pipeline 6) is connected to the air compression system 1 of the steel enterprise to match the high-capacity, high-parameter, and high-efficiency compressed air energy storage system, which not only simplifies the system and saves investment, but also improves power generation efficiency and reduces operating costs. The air flow entering the compressed air network and the energy storage system is flexibly adjusted by adjusting the valve on the main pipe to achieve real-time buffering of the load fluctuation of the compressed air network and flexible adjustment of the air supply volume of the gas storage reservoir.

[0066] In the present application, the waste heat of the steel enterprise is used to heat the compressed air during the energy release stage, thereby realizing the utilization of the waste heat resources of the steel enterprise and improving the efficiency of the compressed air energy storage system.

[0067] The user-side compressed air energy storage system provided in the embodiment of the present application can utilize the existing air compression system 1 equipment and waste heat resources of the steel enterprise, and transfer the load of the air compression system 1 during the peak electricity consumption period to the low electricity consumption period through the compressed air energy storage technology. While ensuring continuous gas supply, it can also realize high-pressure air expansion and power generation, greatly reducing the gas cost of the steel enterprise and the construction cost of compressed air energy storage, and fully improving the comprehensive energy utilization rate and equipment capital utilization rate.

[0068] Among them, during the low electricity consumption period, the air compression system 1 of the steel enterprise runs at full load. As the first-stage compression process of compressed air energy storage, the raw air is filtered and compressed to 0.8mPa. Part of the compression heat generated in this process is used for the regenerative air dryer to dehumidify the compressed air. Under the condition of ensuring the gas consumption during the low electricity consumption period, the purified remaining compressed air enters the secondary pressurization system 2 and is compressed to a high pressure state by the compressor in multiple stages. The compression heat generated in this process is recovered by the circulating heat storage medium, and the moisture in the air is completely removed through the steam-water separation heat exchanger 32, becoming dry high-pressure air at room temperature and stored in the high-pressure gas storage system 4. During the peak electricity consumption period, the compressed air is drawn out from the high-pressure gas storage system 4, and the compressed air is preheated using the compression heat stored in the heat storage medium. At the same time, the waste heat resources of the steel enterprise can be used to reheat the compressed air to fully improve its working capacity. High-temperature and high-pressure air is used to perform work through a multi-stage air turbine expander with back pressure, driving the generator to generate electricity. The air pressure at the expander outlet is then controlled to supply air through the compressed air pipeline 6, thereby replacing the original air compressor unit of the steel enterprise during peak hours, thus forming a comprehensive utilization of air supply, energy storage and waste heat.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0070] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A user-side compressed air energy storage system, characterized in that: include: The air compression system compresses the raw air and delivers the generated compressed air to the compressed air pipeline and the secondary pressurization system; A secondary pressurizing system, connected to the air compression system, re-pressurizes the compressed air delivered by the air compression system and then delivers it to the high-pressure gas storage system; A heat storage and heat exchange system, connected to the secondary pressurization system, collects and stores compression heat generated by the secondary pressurization system when pressurizing air; A high-pressure gas storage system, connected to the secondary pressurization system, storing the high-pressure air delivered by the secondary pressurization system; an expansion power generation system connected to the heat storage and heat exchange system and the high-pressure gas storage system, using the compression heat stored in the heat storage and heat exchange system to heat the high-pressure air stored in the high-pressure gas storage system, using the heated high-pressure air to drive the air expansion generator to generate electricity, and introducing the compressed air at the outlet of the air expansion generator into the compressed air pipeline; The compressed air pipeline is connected to the air compression system and the expansion power generation system to deliver the compressed air delivered by the air compression system and the expansion power generation system to the gas-consuming equipment.

2. The user-side compressed air energy storage system according to claim 1, characterized in that: The air compression system includes at least one air compression mechanism, each of which includes an air filter, an air compressor unit and a reheat air dryer connected in sequence; wherein the reheat air dryer of each air compression mechanism is connected to the compressed air pipeline and the secondary pressurization system through a pipeline.

3. The user-side compressed air energy storage system according to claim 1, characterized in that: The two-stage pressurizing system includes at least one pressurizing mechanism, each of which includes a centrifugal air compressor unit and a compressed air bypass with a flow regulating valve connected to the centrifugal air compressor unit; wherein the centrifugal air compressor unit of each pressurizing mechanism is connected to the air compression system, and the compressed air bypass with a flow regulating valve is connected to the high-pressure air storage system.

4. The user-side compressed air energy storage system according to claim 3, characterized in that: The heat storage and heat exchange system includes at least one heat storage mechanism, each of which includes a tubular heat exchanger, a steam-water separation heat exchanger, a cold water storage tank, a hot water storage tank and a circulation pump; wherein, The tubular heat exchanger is connected to the centrifugal air compressor unit, the cold water storage tank, and the hot water storage tank respectively. The circulating pump is installed on the circulation loop formed by the tubular heat exchanger, the cold water storage tank, and the hot water storage tank. The steam-water separation heat exchanger is installed between the centrifugal air compressor unit and the compressed air bypass with a flow regulating valve.

5. The user-side compressed air energy storage system according to claim 4, characterized in that: The heat storage medium in the tubular heat exchanger, the cold water storage tank and the hot water storage tank includes pressurized water, heat transfer oil or molten salt.

6. The user-side compressed air energy storage system according to claim 1, characterized in that: The high-pressure gas storage system includes a compressed air storage reservoir, which is connected to the secondary pressurization system and the expansion power generation system.

7. The user-side compressed air energy storage system according to claim 1, characterized in that: The expansion power generation system includes a tubular heat exchanger, a waste heat exchanger and an air expansion generator connected in sequence, the tubular heat exchanger is also connected to the heat storage and heat exchange system, the waste heat exchanger is also connected to an external waste heat resource, and the air expansion generator is also connected to the compressed air pipeline.

8. The user-side compressed air energy storage system according to claim 1, characterized in that: During the low electricity consumption period, the air compression system compresses the raw air and delivers part of the compressed air to the compressed air pipeline, and introduces the other part of the compressed air into the secondary pressurization system, and the secondary pressurization system compresses the compressed air again to obtain high-pressure air and delivers the high-pressure air to the high-pressure air storage system for storage; in the above process, the heat storage and heat exchange system is used to recover the compression heat of each level through the heat exchanger and store it in the heat storage medium; During peak electricity consumption, high-pressure air is drawn out from the high-pressure gas storage system and preheated using the compression heat stored in the heat storage medium. At the same time, external waste heat resources can be used to reheat the high-pressure air. The reheated high-pressure air drives the generator in the expansion power generation system to generate electricity, and the air output from the expansion power generation system outlet is incorporated into the compressed air pipeline for gas supply.

9. The user-side compressed air energy storage system according to claim 2, characterized in that: During the low electricity consumption period, all air compressor units in the air compression system operate at full load. When each air compression mechanism is working, the raw air is sucked into the air filter of the air compression mechanism through the first pipe, and then enters the air compressor unit through the second pipe. The second pipe is provided with a first flow regulating valve; the compressed air enters the reheat air dryer through the third pipe, and the dry and purified compressed air output by the reheat air dryer is collected in the compressed air pipeline. A part of the compressed air is controlled to enter the compressed air pipeline through the second flow regulating valve provided on the compressed air pipeline, and the other part enters the secondary pressurization system.

10. The user-side compressed air energy storage system according to claim 7, characterized in that: During peak electricity consumption, high-pressure air is introduced from the high-pressure gas storage system into the expansion power generation system. The flow rate of high-pressure air entering the expansion power generation system is controlled by a flow regulating valve, and the pressure of high-pressure air entering the expansion power generation system is controlled by a throttle valve. The high-pressure air is preheated in the tubular heat exchanger using the compression heat stored in the heat storage medium, and then enters the waste heat exchanger, where it is reheated using external waste heat resources, and then enters the air expansion generator to drive the generator to generate electricity. The air pressure at the outlet of the air expansion generator is then controlled to be incorporated into the compressed air pipeline for air supply. If the air supply meets the gas demand at this time, the air compression system can be unloaded. If the air supply is not enough to meet the gas demand at this time, some air compressor units of the air compression system can be unloaded or operated at low load.

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