Optimized utilization system based on sintering circular cooler low-temperature exhaust gas waste heat resources

Abstract

The invention discloses an optimized utilization system based on sintering circular cooler low-temperature exhaust gas waste heat resources, which is characterized in that heat of a large flue of a sintering machine and flue gas from I to IV sections of a circular cooler is transferred to heat medium water through a flue gas-water heat exchanger for refrigeration and heating, flue gas waste heat is recycled, the waste heat recovery efficiency is improved, and the energy consumption is reduced. And a feasible scheme is provided for energy conservation and carbon reduction in the iron and steel industry. According to the main technical scheme, the optimized utilization system based on the sintering circular cooler low-temperature waste gas waste heat resources is characterized in that a large flue of a sintering machine is connected with a second flue gas-water heat exchanger, the I-II section of the circular cooler is connected with a first flue gas-water heat exchanger, and the second flue gas-water heat exchanger is connected with the first flue gas-water heat exchanger; the section III of the circular cooler is connected with a fourth flue gas-water heat exchanger, the section IV of the circular cooler is connected with a third flue gas-water heat exchanger, and the third flue gas-water heat exchanger is connected with the fourth flue gas-water heat exchanger; and the cold supply system and the heat supply system are connected with the first to fourth flue gas-water heat exchangers. The flue gas waste heat recovery device is mainly used for flue gas waste heat recovery.

Description

Technical Field

[0001] The invention relates to the field of flue gas waste heat treatment in steel plants, and in particular to an optimization utilization system based on low-temperature waste gas waste heat resources of a sintering ring cooler. Background Art

[0002] The steel industry is one of the typical high-energy consumption industries. How to efficiently use energy and reduce carbon emissions has become the focus of the industry. As an important part of the long-process steel production, the sintering process accounts for about 10% of the comprehensive energy consumption per ton of steel in steel enterprises, second only to the ironmaking process. It is the second largest energy consumer in steel production. Energy saving in the sintering process is an important part of energy saving and carbon reduction in steel enterprises, and it is also an important step in achieving the binding indicators of energy saving and carbon reduction.

[0003] Due to the limitation of waste heat recovery technology, nearly 50% of the total energy consumption of the sintering process is discharged into the atmosphere in the form of sensible heat of sintering machine flue gas and ring cooler flue gas. This part of the discharged heat energy, especially the low-temperature flue gas (such as 120-160℃ large flue waste heat), has been underestimated by steel companies due to the limitations of recovery technology and management neglect. In fact, the potential for low-temperature waste heat recovery is huge, especially the low-temperature waste heat of large flues, which has abundant heat sources and considerable recovered heat, and has great potential for energy saving and carbon reduction. In the steel production process, more attention should be paid to the recovery and utilization of waste heat resources.

[0004] The ring cooler in the sintering process is used to cool the high-temperature sintered ore, and a large amount of hot flue gas is generated. Due to the different cooling parts, the temperature range is also quite different. At present, most steel plants have only installed heat exchangers or boiler systems in sections I and II of the ring cooler to recover the waste heat of the high-temperature flue gas to generate electricity or provide steam for the plant area. This part of the waste heat can also be used for combustion in the ignition furnace or preheating the mixture after purification, thereby reducing fuel consumption. However, the low-grade hot air discharged from sections III and IV of the ring cooler has a temperature between 100-200°C and cannot generate steam. There is a general lack of effective recovery methods, resulting in most of the flue gas waste heat being directly discharged, causing a lot of resource waste. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides an optimization utilization system based on the waste heat resources of low-temperature exhaust gas from a sintering ring cooler. The flue gas from the sintering machine flue and sections I to IV of the ring cooler is transferred to heat medium water through a flue gas-water heat exchanger, which is then used for cooling and heating purposes, thereby realizing the recovery and utilization of flue gas waste heat, improving the flue gas waste heat recovery efficiency, and providing a feasible solution for energy conservation and carbon reduction in the steel industry.

[0006] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0007] On the one hand, an embodiment of the present invention provides a system for optimizing utilization of waste heat resources of low-temperature exhaust gas from a sintering ring cooler, comprising:

[0008] A sintering machine flue (9), a ring cooler (26), a second flue gas-water heat exchanger (4), a first flue gas-water heat exchanger (3), a third flue gas-water heat exchanger (5), a fourth flue gas-water heat exchanger (6), a cooling system, a heating system and a blower (28);

[0009] The annular cooler (26) comprises annular cooler sections I-II, annular cooler section III and annular cooler section IV, and the blower (28) is connected to the annular cooler (26);

[0010] The flue gas outlet of the sintering machine flue (9) is connected to the flue gas inlet of the second flue gas-water heat exchanger (4), the flue gas outlet of the ring cooler section I-II is connected to the flue gas inlet of the first flue gas-water heat exchanger (3), and the heat medium inlet of the second flue gas-water heat exchanger (4) is connected to the heat medium outlet of the first flue gas-water heat exchanger (3);

[0011] The flue gas outlet of the ring cooler section III is connected to the flue gas inlet of the fourth flue gas-water heat exchanger (6), the flue gas outlet of the ring cooler section IV is connected to the flue gas inlet of the third flue gas-water heat exchanger (5), and the heat medium outlet of the third flue gas-water heat exchanger (5) is connected to the heat medium inlet of the fourth flue gas-water heat exchanger (6);

[0012] The cooling system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger (4), the heat medium inlet of the first flue gas-water heat exchanger (3), the heat medium inlet of the third flue gas-water heat exchanger (5) and the heat medium outlet of the fourth flue gas-water heat exchanger (6);

[0013] The heating system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger (4), the heat medium inlet of the first flue gas-water heat exchanger (3), the heat medium inlet of the third flue gas-water heat exchanger (5) and the heat medium outlet of the fourth flue gas-water heat exchanger (6).

[0014] The cooling system comprises a first refrigeration unit (1), a second refrigeration unit (2), a cooling tower (39) and a refrigerant water exchange station (44);

[0015] The heat medium inlet of the first refrigeration unit (1) is connected to the heat medium outlet of the second flue gas-water heat exchanger (4) through a third heat circulation water pump (47), the heat medium outlet of the first refrigeration unit (1) is connected to the heat medium inlet of the first flue gas-water heat exchanger (3), and a first valve (32) is connected between the first refrigeration unit (1) and the second flue gas-water heat exchanger (4);

[0016] The heat medium outlet of the second refrigeration unit (2) is connected to the heat medium inlet of the third flue gas-water heat exchanger (5), the heat medium inlet of the second refrigeration unit (2) is connected to the heat medium outlet of the fourth flue gas-water heat exchanger (6) via a fourth heat circulation water pump (48), and a second valve (34) is connected between the second refrigeration unit (2) and the fourth flue gas-water heat exchanger (6);

[0017] The first refrigeration unit (1) and the second refrigeration unit (2) are both connected to a cooling tower (39), and the first refrigeration unit (1) and the second refrigeration unit (2) are both connected to a refrigerant water exchange station (44), and the refrigerant water exchange station (44) is used to supply cold to a cold user (45).

[0018] The cooling system further comprises a first cooling water circulation pump (40), a second cooling water circulation pump (41), a first chilled water circulation pump (42) and a second chilled water circulation pump (43);

[0019] The first cooling water circulation pump (40) is connected between the first refrigeration unit (1) and the cooling tower (39), and the second cooling water circulation pump (41) is connected between the second refrigeration unit (2) and the cooling tower (39);

[0020] The first chilled water circulation pump (42) is connected between the first refrigeration unit (1) and the refrigerant water exchange station (44), and the second chilled water circulation pump (43) is connected between the second refrigeration unit (2) and the refrigerant water exchange station (44);

[0021] A third heat circulation water pump (47) is also connected between the first refrigeration unit (1) and the second flue gas-water heat exchanger (4), and a fourth heat circulation water pump (48) is also connected between the second refrigeration unit (2) and the third flue gas-water heat exchanger (5).

[0022] The heating system comprises a heating water heat exchange station (35), a third valve (37) is connected between the heating water heat exchange station (35) and the heat medium outlet of the second flue gas-water heat exchanger (4), and a fourth valve (38) is connected between the heat medium outlet of the fourth flue gas-water heat exchanger (6) and the heating water heat exchange station (35);

[0023] The heating water heat exchange station (35) is used to provide heat for heating users (36).

[0024] A first heat circulation water pump (31) is connected between the heat medium inlet of the first flue gas-water heat exchanger (3) and the heating water heat exchange station (35), and a second heat circulation water pump (33) is connected between the heat medium inlet of the third flue gas-water heat exchanger (5) and the heating water heat exchange station (35).

[0025] The flue gas from the sintering machine flue (9) passes through the second flue gas-water heat exchanger (4) and is then discharged to the outside. The flue gas outlet of the first flue gas-water heat exchanger (3) is connected to the blower (28). The flue gas from the ring cooler section I-II passes through the first flue gas-water heat exchanger (3) and is then returned to the ring cooler (26) through the blower (28).

[0026] The flue gas from the ring cooler section III passes through the fourth flue gas-water heat exchanger (6) and is then discharged to the outside, and the flue gas from the ring cooler section IV passes through the third flue gas-water heat exchanger (5) and is then discharged to the outside.

[0027] The system also includes:

[0028] A first dust collector (10), a first smoke and air valve (11); a second smoke and air valve (12); a first induced draft fan (13), a desulfurization and denitration device (14), and a first chimney (15) are connected in sequence;

[0029] The first dust collector (10) is also connected to the smoke outlet of the sintering machine flue (9); the smoke inlet of the second smoke-water heat exchanger (4) is connected between the first dust collector (10) and the first smoke-water heat exchanger (11) through the second smoke-air valve (12); and the smoke outlet of the second smoke-water heat exchanger (4) is connected between the first smoke-air valve (11) and the first induced draft fan (13).

[0030] The system also includes:

[0031] A second dust collector (17), a power generation device (18), a first circulating fan (19) and a first flue gas return air valve (20) are connected in sequence, the second dust collector (17) is connected to the flue gas outlet of the ring cooler section I-II, and the flue gas inlet of the first flue gas-water heat exchanger (3) is connected to the first flue gas return air valve (20);

[0032] It also includes a second smoke return air valve (21) and a second circulation fan (27) which are connected to each other, the smoke outlet of the first smoke-water heat exchanger (3) is connected to the second smoke return air valve (21), and the second circulation fan (27) is connected to the blower (28).

[0033] The system also includes:

[0034] A first flue gas air intake valve (23), a second flue gas air intake valve (25), a third dust collector (46), a second induced draft fan (29) and a second chimney (30);

[0035] The first flue gas air intake valve (23) is connected between the ring cooler section III and the fourth flue gas-water heat exchanger (6), the second flue gas air intake valve (25) is connected between the ring cooler section IV and the third flue gas-water heat exchanger (5), the flue gas outlet of the fourth flue gas-water heat exchanger (6) and the flue gas outlet of the third flue gas-water heat exchanger (5) are both connected to the third dust collector (46), and the second induced draft fan (29) is respectively connected to the third dust collector (46) and the second chimney (30).

[0036] Among them, at least some of the connecting pipes in the system are provided with an insulation layer, and the insulation layer is used to reduce the heat exchange between the pipes and the outside.

[0037] An embodiment of the present invention proposes an optimization utilization system based on the waste heat resources of low-temperature exhaust gas from a sintering ring cooler. By equipping the main flue of the sintering machine with a first flue gas-water heat exchanger, equipping sections I-II of the ring cooler with a second flue gas-water heat exchanger, equipping section III of the ring cooler with a fourth flue gas-water heat exchanger, and equipping section IV of the ring cooler with a third flue gas-water heat exchanger, the waste heat of the flue gas from the main flue of the sintering machine and sections I-IV of the ring cooler is utilized, thereby avoiding energy waste and environmental pollution caused by direct emission of low-temperature hot flue gas. By maximizing the waste heat recovery efficiency, the energy consumption of the sintering process can be significantly reduced. At the same time, the use of traditional fossil fuels is reduced, and the system's dependence on external energy is reduced, thereby reducing carbon emissions. This is in line with the circular economy and is the development direction for metallurgical enterprises to achieve energy conservation, carbon reduction and environmental protection.

[0038] At the same time, by connecting the first flue gas-water heat exchanger and the second flue gas-water heat exchanger, as well as the third flue gas-water heat exchanger and the fourth flue gas-water heat exchanger, and combining the flow control of the heat medium, it is possible to first use the low-temperature flue gas for heat exchange according to the heat exchange conditions, and then use the high-temperature flue gas for heat exchange, so as to fully utilize the flue gas temperature.

[0039] In addition, through the setting of cooling system and heating system, both cooling and heating functions can be realized. By adjusting the opening and closing of different valves, the optimal utilization of waste heat resources can be achieved. Whether it is for cooling in summer or heating in winter, the system can respond flexibly and provide a stable supply of cold or heat sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of a system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from a sintering ring cooler provided in an embodiment of the present invention;

[0041] Among them, 1-first refrigeration unit; 2-second refrigeration unit; 3-first flue gas-water heat exchanger; 4-second flue gas-water heat exchanger; 5-third flue gas-water heat exchanger; 6-fourth flue gas-water heat exchanger; 7-sintering machine; 8-waste heat hood; 9-sintering flue; 10-first dust collector; 11-first smoke and air valve; 12-second smoke and air valve; 13-first induced draft fan; 14-desulfurization and denitrification device; 15-first chimney; 16-first flue gas release valve; 17-second dust collector; 18-power generation device; 19-first circulation fan; 20-first flue gas return air valve; 21-second flue gas return air valve; 22-second flue gas release valve; 23-first flue gas intake valve; 24- The third flue gas release valve; 25-the second flue gas intake valve; 26-circulating cooler; 27-the second circulating fan; 28-blower; 29-the second induced draft fan; 30-the second chimney; 31-the first thermal circulation water pump; 32-the first valve; 33-the second thermal circulation water pump; 34-the second valve; 35-heating water heat exchange station; 36-heating users; 37-the third valve; 38-the fourth valve; 39-cooling tower; 40-the first cooling water circulation pump; 41-the second cooling water circulation pump; 42-the first chilled water circulation pump; 43-the second chilled water circulation pump; 44-refrigerant water exchange station; 45-cold users 46-the third dust collector; 47-the third thermal circulation water pump; 48-the fourth thermal circulation water pump. DETAILED DESCRIPTION

[0042] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0043] It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, and to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments will be fully described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention, but do not limit the scope of the present invention in any form.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0047] In the description of the present invention, it should be noted that the terms "first", "second", etc., ordinal numbers are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with ordinal numbers such as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0048] On the one hand, if Figure 1 As shown, the embodiment of the present invention provides a system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from a sintering ring cooler, including:

[0049] Sintering machine large flue 9, annular cooler 26, second flue gas-water heat exchanger 4, first flue gas-water heat exchanger 3, third flue gas-water heat exchanger 5, fourth flue gas-water heat exchanger 6, cooling system, heating system and blower 28;

[0050] The ring cooler 26 includes a ring cooler section I-II, a ring cooler section III and a ring cooler section IV, and a blower 28 is connected to the ring cooler 26;

[0051] The flue gas outlet of the sintering machine flue 9 is connected to the flue gas inlet of the second flue gas-water heat exchanger 4, the flue gas outlet of the ring cooler section I-II is connected to the flue gas inlet of the first flue gas-water heat exchanger 3, and the heat medium inlet of the second flue gas-water heat exchanger 4 is connected to the heat medium outlet of the first flue gas-water heat exchanger 3;

[0052] The flue gas outlet of the ring cooler section III is connected to the flue gas inlet of the fourth flue gas-water heat exchanger 6, the flue gas outlet of the ring cooler section IV is connected to the flue gas inlet of the third flue gas-water heat exchanger 5, and the heat medium outlet of the third flue gas-water heat exchanger 5 is connected to the heat medium inlet of the fourth flue gas-water heat exchanger 6;

[0053] The cooling system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger 4, the heat medium inlet of the first flue gas-water heat exchanger 3, the heat medium inlet of the third flue gas-water heat exchanger 5 and the heat medium outlet of the fourth flue gas-water heat exchanger 6;

[0054] The heating system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger 4 , the heat medium inlet of the first flue gas-water heat exchanger 3 , the heat medium inlet of the third flue gas-water heat exchanger 5 and the heat medium outlet of the fourth flue gas-water heat exchanger 6 .

[0055] It is worth noting that the connection mentioned below refers to connection through a pipeline, that is, the connection objects are connected and communicated through a pipeline, which is known and achievable by those skilled in the art without any objection, and will not be described in detail in the following description.

[0056] During operation, the blower 28 corresponding to the ring cooler section I-II collects the flue gas of 300-400°C of the sintered ore through the waste heat hood 8 on the ring cooler 26, and then directly sends it to the second flue gas-water heat exchanger 3. Alternatively, in some embodiments, the system also includes: a second dust collector 17, a power generation device 18, a first circulation fan 19 and a first flue gas return air valve 20 connected in sequence, the second dust collector 17 is connected to the flue gas outlet of the ring cooler section I-II, and the flue gas inlet of the first flue gas-water heat exchanger 3 is connected to the first flue gas return air valve 20. After the flue gas of the ring cooler section I-II is dedusted by the first dust collector 17, it enters the waste heat power generation device 18. The tail flue gas after the sintering waste heat power generation still has some low-temperature waste heat. This section of low-temperature flue gas is sent to the first flue gas-water heat exchanger 3 through the first circulation fan 19 to complete the heat exchange, thereby realizing the power generation and heat exchange functions. The flue gas after heat exchange can be discharged directly into the atmosphere, or, in some embodiments, the system further includes a second flue gas return air valve 21 and a second circulation fan 27 which are connected to each other, the flue gas outlet of the first flue gas-water heat exchanger 3 is connected to the second flue gas return air valve 21, and the second circulation fan 27 is connected to the blower 28. The flue gas after heat exchange is led back to the I-II section blowing system of the ring cooler by the second circulation fan 27 to complete the flue gas circulation, thereby realizing further utilization of the waste heat of the flue gas. A first flue gas return air valve 20 is provided on the pipeline between the first circulation fan 19 and the first flue gas-water heat exchanger 3, and a second flue gas return air valve 21 is provided on the pipeline between the first flue gas-water heat exchanger 3 and the second circulation fan 27, which can realize the opening and closing control of the flue gas discharge into and out of the first flue gas-water heat exchanger 3. In addition, the ring cooler sections I-II share the same waste heat hood 8, the waste heat hood 8 is connected to a first smoke dissipation pipe, and a first smoke dissipation valve 16 is provided on the first smoke dissipation pipe, thereby realizing the optional direct discharge of smoke from the ring cooler sections I-II.

[0057] The low-temperature flue gas of 120-160°C generated by the sintering flue 9 can be directly used by the second flue gas-water heat exchanger 4. The flue gas of the sintering machine flue 9 is discharged to the outside after passing through the second flue gas-water heat exchanger 4. Alternatively, in some embodiments, the system further includes a first dust collector 10, a first smoke and air valve 11, a second smoke and air valve 12, a first induced draft fan 13, a desulfurization and denitrification device 14, and a first chimney 15 connected in sequence. The first dust collector 10 is connected to the flue gas outlet of the sintering machine flue 9, the flue gas inlet of the second flue gas-water heat exchanger 4 is connected between the first dust collector 10 and the first smoke and air valve 11 through the second smoke and air valve 12, and the flue gas outlet of the second smoke and water heat exchanger 4 is connected between the first smoke and air valve 11 and the first induced draft fan 13. When the flue gas from the sintering machine flue 9 needs to be introduced into the second flue gas-water heat exchanger 4, the first flue gas valve 11 needs to be closed and the second flue gas valve 12 needs to be opened. After the low-temperature flue gas passes through the dust removal device 10 for dust removal, it enters the second flue gas-water heat exchanger 4 for heat exchange through the second flue gas valve 12. After the flue gas is cooled by heat exchange, it passes through the first induced draft fan 13 and the desulfurization and denitration device 14 and is discharged into the atmosphere through the first chimney 15. When it is not necessary to introduce flue gas into the second flue gas-water heat exchanger 4, the first flue gas valve 11 needs to be opened and the second flue gas valve 12 needs to be closed.

[0058] The flue gas of the ring cooler III section passes through the fourth flue gas-water heat exchanger 6 and is discharged to the outside, and the flue gas of the ring cooler IV section passes through the third flue gas-water heat exchanger 5 and is discharged to the outside. It can be discharged directly, or, in some embodiments, the system further includes a first flue gas intake valve 23, a second flue gas intake valve 25, a third dust collector 46, a second induced draft fan 29 and a second chimney 30. The first flue gas intake valve 23 is connected between the ring cooler III section and the fourth flue gas-water heat exchanger 6, the second flue gas intake valve 25 is connected between the ring cooler IV section and the third flue gas-water heat exchanger 5, the flue gas outlet of the fourth flue gas-water heat exchanger 6 and the flue gas outlet of the third flue gas-water heat exchanger 5 are both connected to the third dust collector 46, and the second induced draft fan 29 is connected to the third dust collector 46 and the second chimney 30 respectively. The waste heat hoods 8 of the ring cooler section III and the ring cooler section IV are respectively connected to the second smoke dispersing duct and the third smoke dispersing duct, and the second smoke dispersing duct and the third smoke dispersing duct are respectively provided with a second smoke dispersing valve 22 and a third smoke dispersing valve 24. When utilizing the 100-200°C low-temperature flue gas waste heat of the ring cooler section III and the ring cooler section IV, the second flue gas release valve 22 and the third flue gas release valve 24 need to be closed, the first flue gas intake valve 23 and the second flue gas intake valve 25 need to be opened, the blower 28 of the ring cooler section IV blows air into the ring cooler section IV, the low-temperature flue gas after cooling the sintered ore in the ring cooler section IV passes through the waste heat hood 8 corresponding to the ring cooler section IV and is collected into the third flue gas-water heat exchanger 5, the blower 28 of the ring cooler section III blows air into the ring cooler section III, the low-temperature flue gas after cooling the sintered ore in the ring cooler section III passes through the waste heat hood 8 corresponding to the ring cooler section III and is collected into the fourth flue gas-water heat exchanger 6. The flue gases after heat exchange cooling in the ring cooler section III and the ring cooler section IV are collected, combined, and dust removed in the second dust collector 46, and then discharged into the atmosphere through the second induced draft fan 29 and the second chimney 30.

[0059] Corresponding to the first flue gas-water heat exchanger 3, the second flue gas-water heat exchanger 4, the third flue gas-water heat exchanger 5, and the fourth flue gas-water heat exchanger 6, the heat exchange method between the low-temperature flue gas and the heat medium water is countercurrent heat transfer, so that the heat medium water can obtain the maximum heat energy and improve the heat transfer efficiency. More specifically, in the first flue gas-water heat exchanger 3 and the second flue gas-water heat exchanger 4, as shown in Figure 1 Taking the direction shown in FIG. 1 as an example, the heat medium flows counterclockwise, that is, it first passes through the first flue gas-water heat exchanger 3 for heat exchange, and then flows to the second flue gas-water heat exchanger 4 to exchange heat with the flue gas of the sintering flue 9 with a higher temperature. Figure 1Taking the direction shown as an example, the heat medium flows clockwise, that is, it first passes through the flue gas outflow end of the third flue gas-water heat exchanger 5 for heat exchange, and then flows into the fourth flue gas-water heat exchanger 6 to exchange heat with the flue gas of the ring cooler III section with a higher temperature. That is, the heat medium water first passes through the first flue gas-water heat exchanger 3 or the third flue gas-water heat exchanger 5, and uses the flue gas with a lower temperature in the first half of the low-temperature section to preheat the heat medium water. Then the heat medium water passes through the second flue gas-water heat exchanger 4 or the fourth flue gas-water heat exchanger 6, and uses the flue gas with a higher temperature to fully exchange heat with the heat medium water, thereby realizing the efficient recovery and utilization of the waste heat resources of the low-temperature flue gas.

[0060] After the heat medium water is fully heat exchanged through the first flue gas-water heat exchanger 3, the second flue gas-water heat exchanger 4, the third flue gas-water heat exchanger 5, and the fourth flue gas-water heat exchanger 6, the heated heat medium water enters the cooling system and the heating system as a heat source. In summer, the cooling system can be started to meet the cold source demand, and in winter, the heating system is started, thereby realizing the efficient use of the waste heat of low-temperature flue gas throughout the year. In the following text, a more detailed description of the embodiments will be given in combination with more specific implementation methods of the cooling system and the heating system.

[0061] To further verify the feasibility of this application, take the actual operation data of a steel enterprise as an example:

[0062] The inlet temperature of the second flue gas-water heat exchanger 4 corresponding to the sintering large flue 9 is: T4 in = 150°C, and the outlet temperature of the second flue gas-water heat exchanger 4 is T4 out = 110°C;

[0063] The tail flue gas temperature after sintering waste heat power generation, i.e., the inlet temperature of the first flue gas-water heat exchanger 3 , is T3 in = 130° C., and the outlet temperature of the first flue gas-water heat exchanger 3 is T3 out = 100° C.;

[0064] The inlet temperature of the fourth flue gas-water heat exchanger 6 corresponding to the ring cooler section III is: T6 in = 170°C, and the outlet temperature of the fourth flue gas-water heat exchanger 6 is: T6 out = 110°C;

[0065] The inlet temperature of the third flue gas-water heat exchanger 5 corresponding to the ring cooler IV section is: T5in=120°C, and the outlet temperature of the third flue gas-water heat exchanger 5 is: T5in=90°C;

[0066] Flue gas mass flow rate: sintering flue 9 flue gas mass flow rate, i.e., the second flue gas-water heat exchanger 4 flue gas mass flow rate: m4 = 15kg / s; sintering waste heat power generation, i.e., the tail flue gas flow rate of the waste heat power generation device 18, i.e., the first flue gas-water heat exchanger 3 flue gas flow rate: m3 = 20kg / s; ring cooler III section flue gas flow rate, i.e., the fourth flue gas-water heat exchanger 6 flue gas flow rate: m6 = 20kg / s; ring cooler IV section flue gas flow rate, i.e., the third flue gas-water heat exchanger 5 flue gas flow rate: m5 = 15kg / s;

[0067] Specific heat capacity of flue gas: Specific heat capacity of flue gas C≈1.1kJ / kg·℃;

[0068] According to the formula: Qi = mi × C × Ti in - Ti out, calculate the heat recovery of each flue gas-water heat exchanger:

[0069] Q4=15kg / s×1.1kJ / kg·℃×(150℃-100℃)=825kJ / s=0.825MW;

[0070] Q3=12kg / s×1.1kJ / kg·℃×(130℃-90℃)=528kJ / s=0.528MW;

[0071] Q6=15kg / s×1.1kJ / kg·℃×(170℃-110℃)=990kJ / s=0.99MW;

[0072] Q5=10kg / s×1.1kJ / kg·℃×(120℃-90℃)=330kJ / s=0.33MW;

[0073] For the calculation of total waste heat recovery, add up the waste heat recovery of each part:

[0074] Qtotal = 0.825MW + 0.528MW + 0.99MW + 0.33MW = 2.673MW;

[0075] Energy saving and carbon reduction calculation of fuel substitution, assuming that the substituted fuel is standard coal, the combustion calorific value of standard coal is H standard coal = 29307.6 kJ / kg, and the combustion efficiency is η combustion = 85%;

[0076] According to the formula:

[0077] M = Q total / η combustion × H standard coal = 2.673MW / 85% × 29307.6kJ / kg = 0.107kg / s;

[0078] The carbon emission factor per kilogram of standard coal is E standard coal = 2.49 kg CO 2 / kg;

[0079] According to the formula:

[0080] ERco 2 =M×E standard coal=0.107kg / s×2.49kg CO 2 / kg = 0.266kg CO 2 / s

[0081] Through the waste heat utilization system, 0.266kg CO can be reduced 2 / s emissions, which not only significantly reduced energy consumption, but also achieved considerable carbon emission reduction benefits.

[0082] An embodiment of the present invention proposes an optimization utilization system based on the waste heat resources of low-temperature exhaust gas from a sintering ring cooler. By equipping the main flue of the sintering machine with a first flue gas-water heat exchanger, equipping sections I-II of the ring cooler with a second flue gas-water heat exchanger, equipping section III of the ring cooler with a fourth flue gas-water heat exchanger, and equipping section IV of the ring cooler with a third flue gas-water heat exchanger, the waste heat of the flue gas from the main flue of the sintering machine and sections I-IV of the ring cooler is utilized, thereby avoiding energy waste and environmental pollution caused by direct emission of low-temperature hot flue gas. By maximizing the waste heat recovery efficiency, the energy consumption of the sintering process can be significantly reduced. At the same time, the use of traditional fossil fuels is reduced, and the system's dependence on external energy is reduced, thereby reducing carbon emissions. This is in line with the circular economy and is the development direction for metallurgical enterprises to achieve energy conservation, carbon reduction and environmental protection.

[0083] At the same time, by connecting the first flue gas-water heat exchanger and the second flue gas-water heat exchanger, as well as the third flue gas-water heat exchanger and the fourth flue gas-water heat exchanger, and combining the flow control of the heat medium, it is possible to first use the low-temperature flue gas for heat exchange according to the heat exchange conditions, and then use the high-temperature flue gas for heat exchange, so as to fully utilize the flue gas temperature.

[0084] In addition, through the setting of cooling system and heating system, both cooling and heating functions can be realized. By adjusting the opening and closing of different valves, the optimal utilization of waste heat resources can be achieved. Whether it is for cooling in summer or heating in winter, the system can respond flexibly and provide a stable supply of cold or heat sources.

[0085] There are many ways to implement the cooling system and the heating system. Several feasible implementations are given below as examples. It should be understood that the cooling system and the heating system are not limited to these.

[0086] In one embodiment, the cooling system includes a first refrigeration unit 1, a second refrigeration unit 2, a cooling tower 39 and a refrigerant water exchange station 44. The heat medium inlet of the first refrigeration unit 1 is connected to the heat medium outlet of the second flue gas-water heat exchanger 4 through a third heat circulation water pump 47, the heat medium outlet of the first refrigeration unit 1 is connected to the heat medium inlet of the first flue gas-water heat exchanger 3, and a first valve 32 is connected between the first refrigeration unit 1 and the second flue gas-water heat exchanger 4. The heat medium outlet of the second refrigeration unit 2 is connected to the heat medium inlet of the third flue gas-water heat exchanger 5, the heat medium inlet of the second refrigeration unit 2 is connected to the heat medium outlet of the fourth flue gas-water heat exchanger 6 through a fourth heat circulation water pump 48, and a second valve 34 is connected between the second refrigeration unit 2 and the fourth flue gas-water heat exchanger 6; the first refrigeration unit 1 and the second refrigeration unit 2 are both connected to the cooling tower 39, and the first refrigeration unit 1 and the second refrigeration unit 2 are both connected to the refrigerant water exchange station 44, and the refrigerant water exchange station 44 is used to provide cooling for cold users 45. The heating system includes a heating water heat exchange station 35, a third valve 37 is connected between the heating water heat exchange station 35 and the heat medium outlet of the second flue gas-water heat exchanger 4, a fourth valve 38 is connected between the heat medium outlet of the fourth flue gas-water heat exchanger 6 and the heating water heat exchange station 35, and the heating water heat exchange station 35 is used to provide heating for heating users 36.

[0087] The first refrigeration unit 1 and the second refrigeration unit 2 can both be hot water type lithium bromide absorption refrigeration units for producing refrigerant water.

[0088] Summer high temperature cooling stage:

[0089] The first valve 32 and the second valve 34 are opened, and the third valve 37 and the fourth valve 38 are closed. The chilled water prepared by the first refrigeration unit 1 and the second refrigeration unit 2 provides a cold source for the cold user. The first refrigeration unit 1 and the second refrigeration unit 2 are respectively connected to the cooling tower 39 through a cooling water pipeline, and the cooling water enters the common cooling tower 39. Further, the cooling system also includes a first cooling water circulation pump 40 and a second cooling water circulation pump 41. The first cooling water circulation pump 40 is connected between the first refrigeration unit 1 and the cooling tower 39, and the second cooling water circulation pump 41 is connected between the second refrigeration unit 2 and the cooling tower 39. The first cooling water circulation pump 40 and the second cooling water circulation pump 41 are used to increase the pressure of the cooling water circulation to overcome the resistance along the way. The first refrigeration unit 1 and the second refrigeration unit 2 are respectively connected to the refrigerant water exchange station 44 through a chilled water pipeline, and the chilled water is distributed to the cold user 45 through the refrigerant water exchange station 44. The cooling system also includes a first chilled water circulation pump 42 and a second chilled water circulation pump 43. The first chilled water circulation pump 42 is connected between the first refrigeration unit 1 and the refrigerant water exchange station 44, and the second chilled water circulation pump 43 is connected between the second refrigeration unit 2 and the refrigerant water exchange station 44 to increase the pressure of the chilled water circulation and overcome the resistance along the way.

[0090] Winter low temperature heating stage:

[0091] Close the first valve 32 and the second valve 34, and open the third valve 37 and the fourth valve 38. A branch in the hot water inlet pipeline is connected to the heating water heat exchange station 35 through the heat medium inlet pipeline. The heat medium return pipeline flowing out of the heating water heat exchange station 35 branches out two bypass pipelines to form a connection point. At the same time, along the flow direction of the heat medium inlet, the third valve 37 and the fourth valve 38 are respectively provided on the left and right sides of the connecting pipeline. Along the flow direction of the heat medium return water, the first heat circulation water pump 31 is connected between the heat medium outlet of the first flue gas-water heat exchanger 3 and the heating water heat exchange station 35, and the second heat circulation water pump 33 is connected between the heat medium inlet of the third flue gas-water heat exchanger 5 and the heating water heat exchange station 35 to overcome the resistance along the way for the hot water circulation pressure increase. The heat medium water shares the heating water heat exchange station 35, and is sent to the heating user 36 through the heating water heat exchange station 35 to meet the heating demand.

[0092] In one embodiment, at least some of the connecting pipes in the system are provided with an insulation layer, and the insulation layer is used to reduce the heat exchange between the pipes and the outside. For example, the connecting pipe between the first flue gas-water heat exchanger 3 and the first refrigeration unit, the connecting pipe between the second refrigeration unit and the third flue gas-water heat exchanger, etc., are all provided with an insulation layer.

[0093] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers, characterized in that: include: A sintering machine flue (9), a ring cooler (26), a first flue gas-water heat exchanger (3), a second flue gas-water heat exchanger (4), a third flue gas-water heat exchanger (5), a fourth flue gas-water heat exchanger (6), a cooling system, a heating system and a blower (28); The annular cooler (26) comprises annular cooler sections I-II, annular cooler section III and annular cooler section IV, and the blower (28) is connected to the annular cooler (26); The flue gas outlet of the sintering machine flue (9) is connected to the flue gas inlet of the second flue gas-water heat exchanger (4), the flue gas outlet of the ring cooler section I-II is connected to the flue gas inlet of the first flue gas-water heat exchanger (3), and the heat medium inlet of the second flue gas-water heat exchanger (4) is connected to the heat medium outlet of the first flue gas-water heat exchanger (3); The flue gas outlet of the ring cooler section III is connected to the flue gas inlet of the fourth flue gas-water heat exchanger (6), the flue gas outlet of the ring cooler section IV is connected to the flue gas inlet of the third flue gas-water heat exchanger (5), and the heat medium outlet of the third flue gas-water heat exchanger (5) is connected to the heat medium inlet of the fourth flue gas-water heat exchanger (6); The cooling system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger (4), the heat medium inlet of the first flue gas-water heat exchanger (3), the heat medium inlet of the third flue gas-water heat exchanger (5) and the heat medium outlet of the fourth flue gas-water heat exchanger (6); The heating system is respectively connected to the heat medium outlet of the second flue gas-water heat exchanger (4), the heat medium inlet of the first flue gas-water heat exchanger (3), the heat medium inlet of the third flue gas-water heat exchanger (5) and the heat medium outlet of the fourth flue gas-water heat exchanger (6).

2. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The cooling system comprises a first refrigeration unit (1), a second refrigeration unit (2), a cooling tower (39) and a refrigerant water exchange station (44); The heat medium inlet of the first refrigeration unit (1) is connected to the heat medium outlet of the second flue gas-water heat exchanger (4) through a third heat circulation water pump (47), the heat medium outlet of the first refrigeration unit (1) is connected to the heat medium inlet of the first flue gas-water heat exchanger (3), and a first valve (32) is connected between the first refrigeration unit (1) and the second flue gas-water heat exchanger (4); The heat medium outlet of the second refrigeration unit (2) is connected to the heat medium inlet of the third flue gas-water heat exchanger (5), the heat medium inlet of the second refrigeration unit (2) is connected to the heat medium outlet of the fourth flue gas-water heat exchanger (6) through the fourth heat circulation water pump (48), and a second valve (34) is connected between the second refrigeration unit (2) and the fourth flue gas-water heat exchanger (6); The first refrigeration unit (1) and the second refrigeration unit (2) are both connected to the cooling tower (39), and the first refrigeration unit (1) and the second refrigeration unit (2) are both connected to the refrigerant water exchange station (44), and the refrigerant water exchange station (44) is used to supply cold to cold users (45).

3. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 2 is characterized in that: The cooling system further comprises a first cooling water circulation pump (40), a second cooling water circulation pump (41), a first chilled water circulation pump (42) and a second chilled water circulation pump (43); The first cooling water circulation pump (40) is connected between the first refrigeration unit (1) and the cooling tower (39), and the second cooling water circulation pump (41) is connected between the second refrigeration unit (2) and the cooling tower (39); The first chilled water circulation pump (42) is connected between the first refrigeration unit (1) and the refrigerant water exchange station (44), and the second chilled water circulation pump (43) is connected between the second refrigeration unit (2) and the refrigerant water exchange station (44).

4. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The heating system comprises a heating water heat exchange station (35), a third valve (37) is connected between the heating water heat exchange station (35) and the heat medium outlet of the second flue gas-water heat exchanger (4), and a fourth valve (38) is connected between the heat medium outlet of the fourth flue gas-water heat exchanger (6) and the heating water heat exchange station (35); The heating water heat exchange station (35) is used to provide heat for heating users (36).

5. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 4 is characterized in that: A first heat circulation water pump (31) is connected between the heat medium inlet of the first flue gas-water heat exchanger (3) and the heating water heat exchange station (35), and a second heat circulation water pump (33) is connected between the heat medium inlet of the third flue gas-water heat exchanger (5) and the heating water heat exchange station (35).

6. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The flue gas of the sintering machine flue (9) passes through the second flue gas-water heat exchanger (4) and is discharged to the outside. The flue gas outlet of the first flue gas-water heat exchanger (3) is connected to the blower (28). The flue gas of the ring cooler section II I passes through the first flue gas-water heat exchanger (3) and is returned to the ring cooler (26) through the blower (28). The flue gas from the ring cooler section III passes through the fourth flue gas-water heat exchanger (6) and is then discharged to the outside, and the flue gas from the ring cooler section IV passes through the third flue gas-water heat exchanger (5) and is then discharged to the outside.

7. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The system further comprises: A first dust collector (10), a first smoke and air valve (11); a second smoke and air valve (12); a first induced draft fan (13), a desulfurization and denitration device (14), and a first chimney (15) are connected in sequence; The first dust collector (10) is also connected to the smoke outlet of the sintering machine flue (9); the smoke inlet of the second smoke-water heat exchanger (4) is connected between the first dust collector (10) and the first smoke-air valve (11) through the second smoke-air valve (12); and the smoke outlet of the second smoke-water heat exchanger (4) is connected between the first smoke-air valve (11) and the first induced draft fan (13).

8. The system for optimizing utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The system further comprises: A second dust collector (17), a power generation device (18), a first circulating fan (19) and a first flue gas return air valve (20) connected in sequence, the second dust collector (17) is connected to the flue gas outlet of the ring cooler section I-II, and the flue gas inlet of the first flue gas-water heat exchanger (3) is connected to the first flue gas return air valve (20); It also includes a second smoke return air valve (21) and a second circulation fan (27) which are connected to each other, wherein the smoke outlet of the first smoke-water heat exchanger (3) is connected to the second smoke return air valve (21), and the second circulation fan (27) is connected to the blower (28).

9. The system for optimizing the utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: The system further comprises: A first flue gas air intake valve (23), a second flue gas air intake valve (25), a third dust collector (46), a second induced draft fan (29) and a second chimney (30); The first flue gas air intake valve (23) is connected between the ring cooler section III and the fourth flue gas-water heat exchanger (6), the second flue gas air intake valve (25) is connected between the ring cooler section IV and the third flue gas-water heat exchanger (5), the flue gas outlet of the fourth flue gas-water heat exchanger (6) and the flue gas outlet of the third flue gas-water heat exchanger (5) are both connected to the third dust collector (46), and the second induced draft fan (29) is respectively connected to the third dust collector (46) and the second chimney (30).

10. The system for optimizing utilization of waste heat resources of low-temperature exhaust gas from sintering ring coolers according to claim 1 is characterized in that: In the system, at least part of the connecting pipes are provided with a thermal insulation layer, and the thermal insulation layer is used to reduce heat exchange between the pipes and the outside.

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