Waste heat utilization system and method

Abstract

The invention discloses a waste heat utilization system and method, and relates to the technical field of energy conservation, and the waste heat utilization system comprises a steam dragging compressor unit, a heat management system and a power generation system; wherein the steam dragging compressor unit is respectively connected with a factory waste heat steam pipe network and an air conveying pipeline; the heat management system is connected with the automobile towing compressor unit and the air storage system. And the power generation system is connected with the thermal management system. According to the waste heat utilization system and method, energy storage peak regulation and combined heat and power generation of iron and steel enterprises can be achieved, and the energy utilization rate can be increased.

Description

Technical Field

[0001] This application relates to the technical field of energy conservation, and particularly to a waste heat utilization system and method. Background Art

[0002] In the production of iron and steel enterprises, there are a large number of waste heat and energy resources, with a total amount reaching 40% of the total energy consumption of the enterprise. Not only is the quantity huge, but the value of recovery and utilization is also very high. Especially for the low-grade waste heat and energy in iron and steel, such as the waste heat steam of sintering ring cooler exhaust gas, the waste heat steam of converter vaporization cooling system, the waste heat steam of rolling heating furnace system, the waste heat steam of electric furnace shaft furnace, etc. These steams will be directly discharged or used for heating due to their low quality, resulting in a large waste of resources. In addition, with the gradual development of clean energy such as solar energy and wind energy in iron and steel enterprises, the difference between peak and valley electricity prices in the market is gradually increasing. The application of energy storage systems in the iron and steel industry can effectively improve the comprehensive energy utilization rate.

[0003] Currently, the technology for recovering low-grade waste heat and energy in iron and steel is mainly saturated steam power generation technology. However, due to process reasons, the parameters of the generated steam are unstable and it is difficult to store, and the stable energy storage and peak shaving function cannot be achieved.

[0004] This part aims to provide background or context for the embodiments of the present application stated in the claims. The description here is not admitted to be prior art just because it is included in this part. Summary of the Invention

[0005] The purpose of this application is to provide a waste heat utilization system and method that can at least solve one of the above technical problems.

[0006] An embodiment of the present application provides a waste heat utilization system, including a steam-driven compressor unit, a heat management system, and a power generation system; wherein, the steam-driven compressor unit is respectively connected to the waste heat steam pipe network in the factory area and the air conveying pipeline; during the low electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network in the factory area drives the steam-driven compressor unit to compress the air conveyed by the air conveying pipeline, and the steam-driven compressor unit conveys the generated high-temperature compressed air to the heat management system; during the high electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network in the factory area drives the steam-driven compressor unit to generate electricity; the heat management system is respectively connected to the steam-driven compressor unit and the gas storage system, heats the low-temperature condensate water with the high-temperature compressed air generated by the steam-driven compressor unit during the low electricity consumption period, stores the generated high-temperature water, and conveys the cooled compressed air to the gas storage system for storage; heats the compressed air conveyed by the gas storage system with the high-temperature water during the high electricity consumption period, and outputs the heated compressed air to the power generation system; the power generation system is connected to the heat management system and generates electricity driven by the heated compressed air conveyed by the heat management system during the high electricity consumption period.

[0007] In some embodiments, a condensing system is further included. The condensing system is respectively connected to the steam turbine-driven compressor unit and the plant condensate water pipe network, condenses the waste heat steam after work output by the steam turbine-driven compressor unit into low-temperature condensate water, conveys a part of the low-temperature condensate water to the plant condensate water pipe network, and conveys another part of the low-temperature condensate water to the heat management system.

[0008] In some embodiments, the heat management system includes a heat exchange system and a heat storage system; wherein, the heat exchange system is respectively connected to the steam turbine-driven compressor unit and the gas storage system, heats the low-temperature condensate water with the compressed air conveyed by the steam turbine-driven compressor unit during the low electricity consumption period, and conveys the generated high-temperature water to the heat storage system, heats the compressed air conveyed by the gas storage system with the high-temperature water provided by the heat storage system during the high electricity consumption period, and outputs the heated compressed air to the power generation system; the heat storage system is connected to the heat exchange system, stores the high-temperature water conveyed by the heat exchange system during the low electricity consumption period, and conveys the high-temperature water to the heat exchange system during the high electricity consumption period.

[0009] In some embodiments, the steam turbine-driven compressor unit includes a steam turbine, a generator and a compressor. The steam turbine is connected to the compressor through a first diaphragm coupling, and the steam turbine is connected to the generator through a second diaphragm coupling; the steam turbine is respectively connected to the plant waste heat steam pipe network and the condensing system, and the compressor is connected to the air conveying pipeline and the heat exchange system.

[0010] In some embodiments, the system includes at least two stages of the steam turbine-driven compressor unit. During the low electricity consumption period, the high-temperature compressed air output by each stage of the compressor is conveyed to the heat management system, so that the heat management system uses the high-temperature compressed air to heat the low-temperature condensate water. The heat management system also conveys the cooled compressed air to the next stage of the compressor of the current compressor, so that the next stage of the compressor further compresses the cooled compressed air.

[0011] In some embodiments, the condensing system includes a condensing device and a condensate pump. The condensing device is respectively connected to the steam turbine-driven compressor unit, the condensate pump and the heat exchange system, and the condensate pump is also connected to the plant condensate water pipe network.

[0012] In some embodiments, when the system includes at least two stages of the steam turbine-driven compressor unit, the system further includes at least two sets of the condensing systems, and each set of the condensing systems is respectively connected to a steam turbine-driven compressor unit.

[0013] In some embodiments, the heat exchange system includes an air-cooled heat exchanger and an air-heated heat exchanger. The air-cooled heat exchanger is respectively connected to the steam-turbine compressor unit, the condensing device, and the heat storage system. The air-heated heat exchanger is respectively connected to the gas storage system, the heat storage system, and the power generation system.

[0014] In some embodiments, a heat supply system is further included. The heat supply system is respectively connected to the heat storage system and the plant heat supply pipeline network. When there is a heat supply demand in the plant, the heat supply system transports the high-temperature water in the heat storage system to the plant heat supply pipeline network.

[0015] In some embodiments, the power generation system includes an air turbine expansion power generation device. In the power generation system, compressed air exchanges heat with high-temperature water in the heat management system during the inter-stage expansion process.

[0016] The embodiment of the present application provides a waste heat utilization method. Based on the waste heat utilization system described in any of the above embodiments, the method includes:

[0017] During the low electricity consumption period, the waste heat steam transported by the plant waste heat steam pipeline network drives the steam-turbine compressor unit to compress the air transported by the air delivery pipeline. The steam-turbine compressor unit transports the generated high-temperature compressed air to the heat management system. The heat management system uses the compressed air transported by the steam-turbine compressor unit to heat the low-temperature condensate water, stores the generated high-temperature water, and transports the cooled compressed air to the gas storage system for storage.

[0018] During the high electricity consumption period, the waste heat steam transported by the plant waste heat steam pipeline network drives the steam-turbine compressor unit to generate electricity. The gas storage system transports compressed air to the heat management system. The heat management system uses the high-temperature water to heat the compressed air transported by the gas storage system. The power generation system generates electricity driven by the heated compressed air transported by the heat management system.

[0019] In some embodiments, the method further includes: when there is a heat supply demand in the plant, the heat management system also transports high-temperature water to the plant heat supply pipeline network.

[0020] In some embodiments, when there is a heat supply demand in the plant, the plant waste heat steam pipeline network transports a part of the waste heat steam to the heat management system, and the heat management system heats the low-temperature condensate water according to the waste heat steam.

[0021] The waste heat utilization system and method provided by the embodiments of the present application, during the low electricity consumption period, the waste heat steam transported by the plant area waste heat steam pipe network drives the steam-driven compressor unit to compress the air transported by the air transportation pipeline, and the steam-driven compressor unit transports the generated high-temperature compressed air to the heat management system; the heat management system uses the compressed air transported by the steam-driven compressor unit to heat the low-temperature condensate water, stores the generated high-temperature water, and transports the cooled compressed air to the gas storage system for storage; during the high electricity consumption period, the waste heat steam transported by the plant area waste heat steam pipe network drives the steam-driven compressor unit to generate electricity; the gas storage system transports compressed air to the heat management system; the heat management system uses the high-temperature water to heat the compressed air transported by the gas storage system; the power generation system generates electricity driven by the heated compressed air transported by the heat management system. It can be seen that the waste heat utilization system and method provided by the embodiments of the present application can realize energy storage peak shaving and combined heat and power generation of iron and steel enterprises, and can improve energy utilization efficiency. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of a waste heat utilization system provided by an embodiment of the present application.

[0024] Figure 2 It is a schematic structural diagram of a waste heat utilization system provided by an embodiment of the present application.

[0025] Figure 3 It is a schematic structural diagram of a waste heat utilization system provided by an embodiment of the present application. Detailed Embodiments

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0027] Reference is made to the following description and the accompanying drawings, which disclose in detail specific embodiments of the present application and indicate the ways in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope thereby. Within the spirit and terms of the appended claims, the embodiments of the present application include many variations, modifications, and equivalents.

[0028] Features described and / or illustrated for one embodiment can be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0029] It should be emphasized that the term "comprising / including" as used herein refers to the presence of features, whole things, steps, or components, but does not exclude the presence or addition of one or more other features, whole things, steps, or components.

[0030] To better understand the present application, the research background of the present application will be described in detail below.

[0031] The compressed air energy storage system uses compressed air as the energy storage carrier. During the energy storage stage, by utilizing surplus or off-peak electric energy, an electric motor drives a multi-stage compressor to compress air to high pressure (generally 8 - 12 Mpa) and store it in the gas storage system. During this process, the compression heat at each stage is recovered through a heat exchanger and stored in the heat storage medium, completing the conversion of surplus electric energy into air potential energy. During the energy release stage, the compressed air is led out from the gas storage system and expands through a multi-stage air turbine expander to do work and drive a generator to generate electricity. During this process, the compressed heat stored in the heat storage medium is used to heat the expanded air to improve its work capacity, completing the conversion of air potential energy into peak electric energy.

[0032] At present, the theoretical efficiency of the compressed air energy storage system can already reach 70%, but in actual operation, due to insufficient utilization of compression waste heat, problems such as low actual efficiency and high construction cost of the gas storage reservoir have occurred, resulting in high costs, poor economy, and a small application range for independent compressed air energy storage power stations. If the waste heat and energy of iron and steel enterprises are coupled with the energy exchange in the compressed air energy storage process, it can achieve complementary advantages, further improve the operating efficiency of the energy storage system, and at the same time increase the utilization rate of the coupled energy. In addition, the steel used for the pipeline steel gas storage reservoir can be used as fixed assets of iron and steel enterprises, greatly reducing the construction cost.

[0033] Figure 1 is a schematic structural diagram of a waste heat utilization system provided by an embodiment of the present application, as Figure 1 shown, a waste heat utilization system 100 provided by an embodiment of the present application includes: a steam-driven compression unit 10, a heat management system 20, and a power generation system 30; wherein,

[0034] The steam-driven compressor unit 10 is respectively connected to the waste heat steam pipe network 01 of the plant area and the air conveying pipeline 02. During the low electricity consumption period (a well-known term in the field of electric power technology, referring to the time period with relatively low electricity consumption in a day, opposite to the high electricity consumption period), the waste heat steam conveyed by the waste heat steam pipe network 01 of the plant area drives the steam-driven compressor unit 10 to compress the air conveyed by the air conveying pipeline 02. The steam-driven compressor unit 10 conveys the generated high-temperature compressed air (generally at 180°C - 200°C) to the heat management system 20. During the high electricity consumption period (the high electricity consumption period is a well-known term in the field of electric power technology, referring to the period during which the electricity consumption increases significantly and the grid load is at a relatively high level during certain specific time periods in a day), the waste heat steam conveyed by the waste heat steam pipe network 01 of the plant area drives the steam-driven compressor unit 10 to generate electricity;

[0035] The heat management system 20 is respectively connected to the steam-driven compressor unit 10 and the gas storage system 03. During the low electricity consumption period, it uses the high-temperature compressed air generated by the steam-driven compressor unit 10 to heat the low-temperature condensed water (generally around 30°C), stores the generated high-temperature water (generally at 180°C - 200°C), and conveys the cooled compressed air to the gas storage system 03 for storage. During the high electricity consumption period, it uses the high-temperature water to heat the compressed air conveyed by the gas storage system 03 and outputs the heated compressed air to the power generation system 30;

[0036] The power generation system 30 is connected to the heat management system 20 and generates electricity driven by the heated compressed air conveyed by the heat management system 20 during the high electricity consumption period.

[0037] Specifically, during the low electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network 01 of the plant area drives the steam-driven compressor unit 10 to compress the air conveyed by the air conveying pipeline 02. The steam-driven compressor unit 10 conveys the generated high-temperature compressed air to the heat management system 20. The heat management system 20 uses the compressed air conveyed by the steam-driven compressor unit 10 to heat the low-temperature condensed water, stores the generated high-temperature water, and conveys the cooled compressed air to the gas storage system 03 for storage;

[0038] During the high electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network 01 of the plant area drives the steam-driven compressor unit 10 to generate electricity. The gas storage system 03 conveys compressed air to the heat management system 20. The heat management system 20 uses the high-temperature water to heat the compressed air conveyed by the gas storage system 03 and outputs the heated compressed air to the power generation system 30. The power generation system 30 generates electricity driven by the heated compressed air conveyed by the heat management system 20.

[0039] It can be seen that the waste heat utilization system provided by the embodiments of the present application can realize energy storage peak shaving and cogeneration in iron and steel enterprises, and improve energy utilization efficiency.

[0040] As Figure 2 shown, in some embodiments, the waste heat utilization system 100 further includes a condensing system 40. The condensing system 40 is respectively connected to the steam-driven compressor unit 10 and the plant condensate pipe network 04, condenses the waste heat steam after work output by the steam-driven compressor unit 10 into low-temperature condensate water, transports a part of the low-temperature condensate water to the plant condensate pipe network 04, and transports another part of the low-temperature condensate water to the heat management system 20.

[0041] As Figure 1 and Figure 2 shown, in some embodiments, the heat management system 20 includes a heat exchange system 21 and a heat storage system 22; wherein, the heat exchange system 21 is respectively connected to the steam-driven compressor unit 10 and the gas storage system 03, uses the compressed air transported by the steam-driven compressor unit 10 to heat the low-temperature condensate water during the off-peak electricity period, and transports the generated high-temperature water to the heat storage system 22, and uses the high-temperature water provided by the heat storage system 22 to heat the compressed air output by the gas storage system 03 during the peak electricity period, and outputs the heated compressed air to the power generation system 30; the heat storage system 22 is connected to the heat exchange system 21, stores the high-temperature water transported by the heat exchange system 21 during the off-peak electricity period, and transports high-temperature water to the heat exchange system 21 during the peak electricity period.

[0042] As Figures 1 to 3 shown, in some embodiments, the steam-driven compressor unit 10 includes a steam turbine 11, a generator 12 and a compressor 13. The steam turbine 10 is connected to the compressor 13 through a first diaphragm coupling 14, and the steam turbine 11 is connected to the generator 12 through a second diaphragm coupling 15; the steam turbine 10 is respectively connected to the plant waste heat steam pipe network 01 and the condensing system 40, and the compressor 13 is connected to the air delivery pipeline 02, the gas storage system 03 and the heat exchange system 21.

[0043] As Figures 1 to 3 shown, in some embodiments, the waste heat utilization system 100 includes at least two stages of the steam-driven compressor unit 10. During the off-peak electricity period, the high-temperature compressed air output by each stage of the compressor 13 is transported to the heat management system 20, so that the heat management system 20 uses the high-temperature compressed air to heat the low-temperature condensate water, and the heat management system 20 also transports the cooled compressed air to the next-stage compressor 13 of the current compressor 13, so that the next-stage compressor 13 further compresses the cooled compressed air.

[0044] As Figure 2 and Figure 3 shown, in some embodiments, the condensing system 40 includes a condensing device 41 and a condensate pump 42. The condensing device 41 is respectively connected to the steam-driven compressor unit 10, the condensate pump 42, and the heat exchange system 21. The condensate pump 42 is also connected to the plant condensate water pipe network 04.

[0045] As Figures 1 to 3 shown, in some embodiments, when the waste heat utilization system 100 includes at least two stages of the steam-driven compressor units 10, the waste heat utilization system 100 further includes at least two of the condensing systems 40, and each condensing system 40 is respectively connected to one of the steam-driven compressor units 10.

[0046] As Figure 2 and Figure 3 shown, in some embodiments, the heat exchange system 21 includes an air-cooled heat exchanger 211 and an air-heated heat exchanger 212. The air-cooled heat exchanger 211 is respectively connected to the steam-driven compressor unit 10, the condensing device 41, and the heat storage system 22. The air-heated heat exchanger 212 is respectively connected to the gas storage system 03, the heat storage system 22, and the power generation system 30.

[0047] As Figure 3 shown, in some embodiments, a heating system 50 is further included. The heating system 50 is respectively connected to the heat storage system 22 and the plant heating pipe network 05. When there is a heating demand in the plant, the heating system 50 transports the high-temperature water in the heat storage system 22 to the plant heating pipe network 05.

[0048] As Figure 2 and Figure 3 shown, in some embodiments, the heat storage system 22 includes a high-temperature water storage heater, and the heating system 50 includes a hot water supply pump. The high-temperature water storage heater is respectively connected to the heat exchange system 21 and the hot water supply pump; the hot water supply pump is also connected to the plant heating pipe network 05. When there is a heating demand in the plant, the hot water supply pump transports the high-temperature water in the high-temperature water storage heater to the plant heating pipe network 05.

[0049] As Figures 1 to 3 shown, in some embodiments, the power generation system 30 includes an air turbine expansion power generation device. In the power generation system 30, compressed air exchanges heat with high-temperature water in the thermal management system 20 during the inter-stage expansion process.

[0050] Based on the same inventive concept, an embodiment of the present application further provides a waste heat utilization method. The waste heat utilization method provided by an embodiment of the present application is based on the waste heat utilization system 100 described in any of the above embodiments. The method includes:

[0051] During the low electricity consumption period, the waste heat steam transported by the plant waste heat steam pipe network 01 drives the steam turbine compressor unit 10 to compress the air transported by the air transportation pipeline 02. The steam turbine compressor unit 10 transports the generated high-temperature compressed air to the thermal management system 20; the thermal management system 20 uses the compressed air transported by the steam turbine compressor unit 10 to heat the low-temperature condensate water, stores the generated high-temperature water, and transports the cooled compressed air to the gas storage system 03 for storage;

[0052] During the high electricity consumption period, the waste heat steam transported by the plant waste heat steam pipe network 01 drives the steam turbine compressor unit 10 to generate electricity; the gas storage system 03 transports compressed air to the thermal management system 20; the thermal management system 20 uses the high-temperature water to heat the compressed air transported by the gas storage system 03, and outputs the heated compressed air to the power generation system 30; the power generation system 30 generates electricity under the drive of the heated compressed air transported by the thermal management system 20.

[0053] It can be seen that the waste heat utilization method provided by the embodiment of the present application can achieve energy storage peak shaving and combined heat and power generation in iron and steel enterprises, and can improve energy utilization efficiency.

[0054] In some embodiments, the method may further include: when the plant has a heating demand, the thermal management system 20 also transports the high-temperature water to the plant heating pipe network 05.

[0055] In some embodiments, when the plant has a heating demand, the plant waste heat steam pipe network 01 transports a part of the waste heat steam to the thermal management system 20, and the thermal management system 20 heats the low-temperature condensate water according to the waste heat steam.

[0056] To better understand the present application, the following provides a detailed description of the waste heat utilization system and method provided by the present application through a specific embodiment.

[0057] As Figures 1 to 3 shown, the waste heat utilization system 100 can be used in iron and steel enterprises. At this time, the plant waste heat steam pipe network 01 may specifically include a sintering process waste heat steam pipeline, a converter process waste heat steam pipeline, an electric furnace process waste heat steam pipeline, a rolling process waste heat steam pipeline, and other process waste heat steam pipelines, etc.

[0058] The waste heat utilization system 100 includes at least one set of self-cleaning air filters 60 and two sets of steam-driven compressor units 10. Each steam-driven compressor unit 10 includes a steam turbine 11, a generator 12, a compressor 13, a first diaphragm coupling 14, and a second diaphragm coupling 15. The waste heat utilization system 100 further includes two sets of condensing systems 40, and each condensing system 40 includes a condensing device 41. The waste heat utilization system 100 also includes a heat exchange system 21, which includes an air-cooled heat exchanger 211 and an air-heated heat exchanger 212. The waste heat utilization system 100 further includes a heat storage system 22, at least one set of power generation systems 30, and at least one set of heating systems 50.

[0059] During the off-peak electricity consumption period, the waste heat steam resources of the steel enterprise are transported through the pipeline to the inlet of the steam turbine 11 of the steam-driven compressor 10 through the plant waste heat steam pipeline network 01. At this time, the inlet valve of the steam turbine 11 is opened, the first diaphragm coupling 14 between the steam turbine 11 and the compressor 13 is closed, and the second diaphragm coupling 15 between the steam turbine 11 and the generator 12 is disconnected. The waste heat steam drives the steam turbine 11 to drive the compressor 13 to compress the air to a target pressure value (such as 8 Mpa) and store it in the pipeline steel gas storage system 03 through the pipeline. During this process, after the waste heat steam drives the steam turbine 11 to do work, it is condensed into low-temperature condensate by the industrial circulating water of the plant through the condensing device 41, enters the condensate pump 42 through the pipeline for pressurization, and then returns to the plant condensate pipeline network 04 through the low-temperature condensate pipeline. At the same time, a part of the low-temperature condensate enters the air-cooled heat exchanger 211 through the pipeline to exchange heat with the compressed air in the air-cooled heat exchanger 211, and the compressed heat is recovered to become high-temperature water, which is stored in the high-temperature water heat accumulator through the pipeline. When there is a heating demand, it is pressurized by the hot water supply pump and enters the plant heating pipeline network 05. Each equipment system is connected by pipelines, and electric control valves are set on the pipelines.

[0060] During the peak electricity consumption period, the waste heat steam resources of the steel enterprise are transported through the pipeline of the waste heat steam pipe network 01 in the factory area to the inlet of the steam turbine 11 of the steam-driven compressor 10. At this time, the first diaphragm coupling 14 between the steam turbine 11 and the compressor 13 in the steam-driven compressor unit 10 is disconnected, and the second diaphragm coupling 15 between the steam turbine 11 and the generator 12 is closed. The waste heat steam is used to drive the steam turbine 11 to do work and drive the generator 12 to generate electricity. The steam after working is condensed into low-temperature condensate by the industrial circulating water in the factory area through the condensing device 41, enters the condensate pump 42 through the pipeline after pressurization, and then returns to the condensate pipe network 04 in the factory area through the low-temperature condensate pipeline; at the same time, the compressed air is led out from the pipeline steel gas storage system 03, transported through the pipeline to the air heating heat exchanger 212, and the compressed air is preheated by the high-temperature water in the heat accumulator. The heated high-temperature compressed air enters the air turbine expansion power generation system through the pipeline to do work and generate electricity. If there is a heating demand during this process, a part of the steam and condensate can be controlled by the valve to enter the high-temperature water heat accumulator, and after reaching the heating temperature, it enters the factory heating pipe network 05 through the hot water supply pump.

[0061] By setting the high-temperature water heat accumulator, when the heating demand in the factory area is large, the flow rates of the condensate and waste heat steam entering the high-temperature water heat accumulator can be controlled by adjusting the valve switch to meet the heating demand; in addition, the temperature of the hot water in the high-temperature water heat accumulator can be increased during the expansion process, thereby increasing the temperature of the compressed air after heat exchange with the high-temperature water, and further improving the operating efficiency of the air turbine expansion power generation system. The waste heat utilization system and method provided in this embodiment realize energy storage and peak shaving and combined heat and power generation in steel enterprises, and improve energy utilization efficiency. Specifically:

[0062] The waste heat utilization system provided in this embodiment can utilize the waste heat resources of steel enterprises, transfer the load of the air compressor system during the peak electricity consumption period to the off-peak electricity consumption period, realize energy storage and peak shaving in steel enterprises, and can also supply heat to the factory area, fully improving the comprehensive energy utilization efficiency.

[0063] The waste heat utilization system provided in this example includes 2 sets of steam-driven compressor units, 1 set of heat exchange system, 1 set of gas storage system, and 1 set of power generation system. The waste heat utilization system claimed in this application is not limited to this, and can be flexibly adjusted according to production needs. For example, more than 2 sets of steam-driven compressor units may be required, or 2-stage or above coaxial compressors may be required; it may also be a multi-stage or multi-set expansion power generation system. Without departing from the scope defined by the claims, various changes and modifications should fall within the scope protected by this application.

[0064] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element. The orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present application. Unless otherwise expressly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0065] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference may be made to each other, and the differences between each embodiment and other embodiments are emphasized. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0066] In this application, specific embodiments are used to elaborate on the principles and implementation manners of the application. The description of the above embodiments is only used to help understand the method and its core idea of the application; at the same time, for those of ordinary skill in the art, according to the idea of the application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the application.

Claims

1. A waste heat utilization system, characterized in that, It includes a steam-driven compressor unit, a thermal management system, and a power generation system; among them, the steam-driven compressor unit is respectively connected to the waste heat steam pipe network of the factory area and the air conveying pipeline; during the low electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network of the factory area drives the steam-driven compressor unit to compress the air conveyed by the air conveying pipeline, and the steam-driven compressor unit conveys the generated high-temperature compressed air to the thermal management system; during the high electricity consumption period, the waste heat steam conveyed by the waste heat steam pipe network of the factory area drives the steam-driven compressor unit to generate electricity; the thermal management system is respectively connected to the steam-driven compressor unit and the gas storage system, uses the high-temperature compressed air generated by the steam-driven compressor unit to heat the low-temperature condensate during the low electricity consumption period, stores the generated high-temperature water, and conveys the cooled compressed air to the gas storage system for storage; uses the high-temperature water to heat the compressed air conveyed by the gas storage system during the high electricity consumption period, and outputs the heated compressed air to the power generation system; the power generation system is connected to the thermal management system and generates electricity driven by the heated compressed air conveyed by the thermal management system during the high electricity consumption period.

2. The system according to claim 1, characterized in that, It also includes a condensing system, which is respectively connected to the steam-driven compressor unit and the condensate pipe network of the factory area, condenses the waste heat steam after doing work output by the steam-driven compressor unit into low-temperature condensate, conveys a part of the low-temperature condensate to the condensate pipe network of the factory area, and conveys another part of the low-temperature condensate to the thermal management system.

3. The system according to claim 2, wherein The thermal management system includes a heat exchange system and a heat storage system; among them, the heat exchange system is respectively connected to the steam-driven compressor unit and the gas storage system, uses the compressed air conveyed by the steam-driven compressor unit to heat the low-temperature condensate during the low electricity consumption period, and conveys the generated high-temperature water to the heat storage system, uses the high-temperature water provided by the heat storage system to heat the compressed air conveyed by the gas storage system during the high electricity consumption period, and outputs the heated compressed air to the power generation system; the heat storage system is connected to the heat exchange system, stores the high-temperature water conveyed by the heat exchange system during the low electricity consumption period, and conveys the high-temperature water to the heat exchange system during the high electricity consumption period.

4. The system according to claim 3, wherein The steam-driven compressor unit includes a steam turbine, a generator, and a compressor. The steam turbine is connected to the compressor through a first diaphragm coupling, and the steam turbine is connected to the generator through a second diaphragm coupling; the steam turbine is respectively connected to the waste heat steam pipe network of the factory area and the condensing system, and the compressor is connected to the air conveying pipeline and the heat exchange system.

5. The system according to claim 3, characterized in that, The system includes at least two levels of the steam-driven compressor unit. During the low electricity consumption period, the high-temperature compressed air output by each level of the compressor is conveyed to the thermal management system, so that the thermal management system uses the high-temperature compressed air to heat the low-temperature condensate. The thermal management system also conveys the cooled compressed air to the next-level compressor of the current compressor, so that the next-level compressor further compresses the cooled compressed air.

6. The system according to claim 5, wherein The condensing system includes a condensing device and a condensate pump. The condensing device is respectively connected to the steam-driven compressor unit, the condensate pump and the heat exchange system, and the condensate pump is also connected to the plant condensate water pipe network.

7. The system according to claim 6, wherein, When the system includes at least two stages of the steam-driven compressor unit, the system also includes at least two sets of the condensing systems, and each set of the condensing systems is respectively connected to one steam-driven compressor unit.

8. The system according to claim 3, wherein The heat exchange system includes an air-cooled heat exchanger and an air-heated heat exchanger. The air-cooled heat exchanger is respectively connected to the steam-driven compressor unit, the condensing device and the heat storage system, and the air-heated heat exchanger is respectively connected to the gas storage system, the heat storage system and the power generation system.

9. The system according to claim 3, characterized in that, It further includes a heat supply system. The heat supply system is respectively connected to the heat storage system and the plant heat supply pipe network. When there is a heat supply demand in the plant, the heat supply system transports the high-temperature water in the heat storage system to the plant heat supply pipe network.

10. The system according to claim 1, wherein The power generation system includes an air turbine expansion power generation device. In the power generation system, compressed air exchanges heat with high-temperature water in the heat management system during the inter-stage expansion process.

11. A waste heat utilization method, characterized in that, Based on the waste heat utilization system according to any one of the above claims 1 to 10, the method includes: During the low electricity consumption period, the waste heat steam transported by the plant waste heat steam pipe network drives the steam-driven compressor unit to compress the air transported by the air conveying pipeline. The steam-driven compressor unit transports the generated high-temperature compressed air to the heat management system; the heat management system uses the compressed air transported by the steam-driven compressor unit to heat the low-temperature condensate water, stores the generated high-temperature water, and transports the cooled compressed air to the gas storage system for storage; During the high electricity consumption period, the waste heat steam transported by the plant waste heat steam pipe network drives the steam-driven compressor unit to generate electricity; the gas storage system transports compressed air to the heat management system; the heat management system uses the high-temperature water to heat the compressed air transported by the gas storage system; the power generation system generates electricity driven by the heated compressed air transported by the heat management system.

12. The method according to claim 11, wherein The method further includes: When there is a heat supply demand in the plant, the heat management system also transports high-temperature water to the plant heat supply pipe network.

13. The method according to claim 12, characterized in that, When there is a heat supply demand in the plant, the plant waste heat steam pipe network transports a part of the waste heat steam to the heat management system, and the heat management system heats the low-temperature condensate water according to the waste heat steam.

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