Flue gas waste heat recycling system of AOD (argon oxygen decarburization) furnace

Abstract

The utility model discloses an AOD (Argon Oxygen Decarburization) furnace flue gas waste heat recycling system which comprises a vaporization flue, a vaporization flue steam drum, a waste heat boiler, a waste heat boiler steam drum and a deaerator, an inlet of the vaporization flue is positioned above the AOD furnace; a heat exchanger is arranged in the vaporization flue, an inlet of the heat exchanger is connected with a cooling water outlet of the vaporization flue steam pocket through a first inlet pipeline A1, and an outlet of the heat exchanger is communicated with an inlet of the vaporization flue steam pocket through a first outlet pipeline B1; the waste heat boiler is provided with a flue inlet and a flue outlet, and the flue inlet of the waste heat boiler is communicated with the outlet of the vaporization flue; a plurality of medium-temperature evaporators and a waste heat boiler automatic steam pocket are arranged in the waste heat boiler. The AOD furnace waste heat recovery system has the advantages that the waste heat boiler is additionally arranged, after smoke led out of the AOD furnace is subjected to heat exchange through the vaporization flue, waste heat is further recovered through the waste heat boiler, and the waste heat utilization rate is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of metallurgy, and in particular to an AOD furnace flue gas waste heat recovery and utilization system. Background Art

[0002] The primary flue gas generated by the AOD furnace during the blowing process has a temperature of up to 1700°C and carries a large amount of high-grade sensible heat. In order to make the flue gas meet the emission standards, the existing flue gas needs to be cooled and dusted. The production process of some steel mills is to first use a water-cooled flue to cool the high-temperature flue gas to about 1000°C, and then lead two secondary flue gases from the left and right sides of the dog house to mix with the high-temperature primary flue gas. The temperature of the mixed flue gas is 300-500°C, and then it is forced to cool to below 200°C through a mechanical air cooler and enters the bag dust collector. After dust removal, it is led to the chimney for discharge through an induced draft fan.

[0003] However, this traditional method of using water-cooled flue and mixed air to cool high-temperature flue gas to meet emission standards is feasible, but it does not utilize the high-value sensible heat in the high-temperature flue gas, and cooling the flue requires a large amount of circulating cooling water, consuming a large amount of electrical energy, which is very uneconomical. If the flue gas waste heat can be reasonably recovered, the energy consumption index of the steel plant can be greatly reduced and the economic benefits of the steel plant can be improved.

[0004] Therefore, it is necessary to improve the prior art. Summary of the invention

[0005] The utility model aims to provide an AOD furnace flue gas waste heat recovery and utilization system to recover and utilize the flue gas waste heat in view of the existing deficiencies.

[0006] The technical solution adopted by the utility model is: an AOD furnace flue gas waste heat recovery and utilization system, including a vaporization flue, a vaporization flue drum, a waste heat boiler, a waste heat boiler drum and a deaerator;

[0007] The inlet of the vaporization flue is located above the AOD furnace;

[0008] A heat exchanger is provided in the vaporization flue, the inlet of the heat exchanger is connected to the cooling water outlet of the vaporization flue drum through the first inlet pipeline A1, and the outlet of the heat exchanger is connected to the inlet of the vaporization flue drum through the first outlet pipeline B1;

[0009] The waste heat boiler is provided with a flue inlet and a flue outlet, and the flue inlet of the waste heat boiler is connected with the outlet of the vaporization flue;

[0010] A plurality of medium-temperature evaporators and a waste heat boiler automatic steam drum are arranged in the waste heat boiler; the medium-temperature evaporators are arranged in sequence along the flue gas flow direction, the inlet of each medium-temperature evaporator is connected to the outlet of the waste heat boiler steam drum through the second inlet pipeline, and the outlet of each medium-temperature evaporator is connected to the inlet of the waste heat boiler steam drum through the second outlet pipeline;

[0011] The inlet of the deaerator is connected to the desalted water pipeline, the outlet of the deaerator is connected to the water inlet of the vaporization flue drum through the first water supply pipeline C1, and the outlet of the deaerator is connected to the water inlet of the waste heat boiler drum through the second water supply pipeline C2;

[0012] The steam outlet of the vaporization flue drum and the steam outlet of the waste heat pipeline are respectively connected to the steam main pipe of the external network through the steam delivery pipeline.

[0013] According to the above scheme, the waste heat boiler is equipped with five medium-temperature evaporators and one low-temperature evaporator, of which three medium-temperature evaporators are located on the flue gas inlet side; two medium-temperature evaporators and one low-temperature evaporator are located on the flue gas outlet side, and the low-temperature evaporator is located downstream of the two medium-temperature evaporators.

[0014] According to the above scheme, a water supply pump is arranged on the pipeline connected to the outlet of the deaerator, and the outlet of the water supply pump is connected to the first water supply pipeline and the second water supply pipeline through pipelines respectively.

[0015] According to the above scheme, a medium-pressure circulating water pump is arranged on the pipeline (G1) connected to the outlet of the vaporization flue drum, and the outlet of the medium-pressure circulating pump is connected to the first inlet pipeline through the pipeline.

[0016] According to the above scheme, the vaporization flue includes a furnace mouth section, a middle section and a tail section which are connected in sequence through an expansion compensator; the furnace mouth section is located directly above the AOD furnace, and is provided with an oxygen gun hole and a feeding hole, and is equipped with an oxygen gun sleeve and a feeding sleeve; the tail section is connected to the flue gas inlet of the waste heat boiler through an expansion compensator.

[0017] According to the above scheme, the furnace mouth section, the middle section and the tail section are respectively provided with manholes and hand holes.

[0018] According to the above scheme, the outlet of the deaerator is connected to the outlet pipeline F2, and a low-pressure circulating water pump is arranged on the outlet pipeline F2. The outlet of the low-pressure circulating water pump is connected to the cold source inlet of the charging sleeve, the cold source inlet of the oxygen gun sleeve, and the cold source inlet of the low-temperature evaporator of the waste heat boiler through pipelines; the cold source outlet of the charging sleeve, the cold source outlet of the oxygen gun sleeve, and the cold source outlet of the low-temperature evaporator of the waste heat boiler are connected to the inlet of the deaerator through the reflux pipeline.

[0019] According to the above scheme, the flue gas waste heat recovery system also includes a heat accumulator, and the steam outlet of the vaporization flue steam drum and the steam outlet of the waste heat pipeline are respectively connected to the heat accumulator through steam delivery pipelines.

[0020] According to the above solution, the heat accumulator is a pressure variable steam heat accumulator.

[0021] According to the above scheme, an ash discharge valve and an ash hopper are arranged at the bottom of the waste heat boiler.

[0022] The beneficial effects of the utility model are as follows: on the basis of the prior art, the utility model adds a waste heat boiler, and the flue gas drawn out of the AOD furnace is heat exchanged through the vaporization flue, and then flows through the waste heat boiler to further recover the waste heat, and the steam generated after the heat exchange is collected and sent to users for power generation, heating, etc. Compared with the prior art, the utility model can fully recycle the waste heat of the flue gas, thereby improving the utilization rate of the waste heat. The temperature of the flue gas after heat exchange by the waste heat boiler is further reduced, which greatly reduces the electric energy consumed in the subsequent flue gas cooling treatment (forced cooling to below 200°C by an air cooler and entering a bag filter), and has good economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a specific embodiment of the utility model.

[0024] Among them: 1. furnace mouth section; 2. middle section; 3. tail section; 4. expansion compensator; 5. waste heat boiler; 6. waste heat boiler drum; 7. vaporization flue drum; 8. deaerator; 9. medium-pressure circulating water pump; 10. low-pressure circulating water pump; 11. feed water pump; 12. heat accumulator; 13. ash hopper; 14. charging sleeve; 15. oxygen gun sleeve; 16. medium-temperature evaporator; 17. low-temperature evaporator. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] like Figure 1 The AOD furnace flue gas waste heat recovery and utilization system comprises a vaporization flue, a vaporization flue drum 7, a waste heat boiler 5, a waste heat boiler drum 6 and a deaerator 8;

[0027] The inlet of the vaporization flue is located above the AOD furnace;

[0028] A heat exchanger is provided in the vaporization flue, the inlet of the heat exchanger is connected to the cooling water outlet of the vaporization flue drum 7 through the first inlet pipeline A1, and the outlet of the heat exchanger is connected to the inlet of the vaporization flue drum 7 through the first outlet pipeline B1;

[0029] The waste heat boiler 5 is provided with a flue inlet and a flue outlet, and the flue inlet of the waste heat boiler 5 is connected to the outlet of the vaporization flue;

[0030] A plurality of medium-temperature evaporators 16 and an automatic steam drum of the waste heat boiler 5 are provided in the waste heat boiler 5; the medium-temperature evaporators 16 are arranged in sequence along the flue gas flow direction, and the inlet of each medium-temperature evaporator 16 is connected to the outlet of the waste heat boiler steam drum 6 through the second inlet pipeline A2, and the outlet of each medium-temperature evaporator 16 is connected to the inlet of the waste heat boiler steam drum 6 through the second outlet pipeline B2;

[0031] The inlet of the deaerator 8 is connected to the desalted water pipeline D1, the outlet of the deaerator 8 is connected to the water inlet of the vaporization flue drum 7 through the first water supply pipeline C1, and the outlet of the deaerator 8 is connected to the water inlet of the waste heat boiler drum 6 through the second water supply pipeline C2;

[0032] The steam outlet of the vaporization flue drum 7 and the steam outlet of the waste heat pipeline are respectively connected to the steam main of the external network through the steam delivery pipeline E1, and the steam is delivered to each user through the steam main for heating or power generation.

[0033] In the utility model, the flue outlet of the waste heat boiler 5 is connected to the secondary dust removal pipe through the flue gas outlet pipe, and the secondary dust removal flue is connected to the subsequent processing system (such as a bag dust collector); the primary flue gas and the secondary flue gas are mixed at the flue gas outlet pipe. This is the existing technology in the industry and will not be repeated here.

[0034] In this embodiment, the waste heat boiler 5 is configured with five medium-temperature evaporators 16 and one low-temperature evaporator 17, wherein three medium-temperature evaporators 16 are located on the flue gas inlet side; two medium-temperature evaporators 16 and one low-temperature evaporator 17 are located on the flue gas outlet side, and the low-temperature evaporator 17 is located downstream of the two medium-temperature evaporators 16; the flue gas enters from the flue gas inlet of the waste heat boiler 5, flows through each medium-temperature evaporator 16 and the low-temperature evaporator 17 in sequence, and finally flows out through the flue gas outlet of the waste heat boiler 5.

[0035] In the utility model, a feed water pump 11 is provided on the pipeline F1 connected to the outlet of the deaerator 8, and the outlet of the feed water pump 11 is connected to the first water supply pipeline A1 and the second water supply pipeline A2 through pipelines. After being deoxygenated by the deaerator 8, the desalted water enters the vaporization flue drum 7 and the waste heat boiler drum 6 respectively, and provides cooling medium for the vaporization flue and the waste heat boiler 5 respectively. The deaerator 8, the feed water pump 11, the vaporization flue drum 7 and the waste heat boiler drum 6 constitute a feed water deoxygenation subsystem, and the vaporization flue drum 7 and the waste heat boiler drum 6 respectively adjust the feed water flow according to their own water level and steam flow information.

[0036] Preferably, a medium-pressure circulating water pump 9 is provided on the pipeline G1 connected to the outlet of the vaporization flue drum 7, and the outlet of the medium-pressure circulating pump is connected to the first inlet pipeline A1 through a pipeline.

[0037] In the utility model, the heat exchanger in the vaporization flue, the medium-pressure circulating water pump 9 and the vaporization flue drum 7 constitute a medium-pressure forced circulation subsystem. The vaporization flue drum 7 serves as a water distribution and steam collection device. The water coming out of the vaporization flue drum 7 passes through the medium-pressure circulating pump and then enters the heat exchangers of the vaporization flue (such as the furnace mouth section 1, the middle section 2 and the tail section 3) to exchange heat with the high-temperature flue gas. After absorption, a steam-water mixture is formed and enters the vaporization flue drum 7. The steam and water are separated by the vaporization flue, the steam is sent out, and the water enters the medium-pressure circulating pump to start a new cycle.

[0038] In the utility model, the medium-temperature evaporator 16 of the waste heat boiler 5, the waste heat boiler drum 6, the pipelines and the matching pipes constitute a medium-pressure natural circulation system. The whole process is as follows: the waste heat boiler drum 6 also serves as a water distribution and steam collection device. The water from the waste heat boiler drum 6 enters the medium-temperature evaporator 16 of the waste heat boiler 5, exchanges heat with the flue gas, and forms a steam-water mixture, and then returns to the waste heat boiler drum 6, wherein the pressure head generated by the density difference between steam and water can realize natural circulation.

[0039] Preferably, the vaporization flue includes a furnace mouth section 1, a middle section 2 and a tail section 3 which are connected in sequence through an expansion compensator 4; the furnace mouth section 1 is located directly above the AOD furnace, and an oxygen gun hole and a feeding hole are opened on the furnace mouth section 1, and an oxygen gun sleeve 15 and a feeding sleeve 14 are installed, wherein the oxygen gun sleeve 15 is used for blowing oxygen with the oxygen gun, and the feeding sleeve 14 is used for adding materials such as ferroalloys and limestone. This is a mature technology in the industry and will not be repeated here; the tail section 3 is connected to the flue gas inlet of the waste heat boiler 5 through the expansion compensator 4.

[0040] Preferably, the furnace mouth section 1, the middle section 2 and the tail section 3 are respectively provided with manholes and hand holes to facilitate maintenance and ash cleaning.

[0041] In the present invention, the expansion compensator 4 is made of non-metal and is used to absorb the axial displacement caused by the thermal expansion of the vaporization cooling flue. The expansion compensator 4 is a mature structure in the industry and will not be described here.

[0042] In the utility model, heat exchangers are respectively arranged in the furnace mouth section 1, the middle section 2 and the tail section 3, and the inlet of each heat exchanger is connected to the cooling water outlet of the vaporization flue drum 7 through the first inlet pipeline A1, and the outlet of each heat exchanger is connected to the inlet of the vaporization flue drum 7 through the first outlet pipeline B1.

[0043] In the utility model, the outlet of the deaerator 8 is connected to the outlet pipeline F2, and the outlet pipeline F2 is provided with a low-pressure circulating water pump 10. The outlet of the low-pressure circulating water pump 10 is respectively connected to the cold source inlet of the charging sleeve 14, the cold source inlet of the oxygen gun sleeve 15, and the cold source inlet of the low-temperature evaporator 17 of the waste heat boiler 5 through pipelines; the cold source outlet of the charging sleeve 14, the cold source outlet of the oxygen gun sleeve 15, and the cold source outlet of the low-temperature evaporator 17 of the waste heat boiler 55 are respectively connected to the inlet of the deaerator 8 through a reflux pipeline.

[0044] In the utility model, the charging sleeve 14, oxygen gun sleeve 15, low-temperature evaporator 17 of waste heat boiler 5, low-pressure circulating water pump 10, deaerator 8 and pipelines and matching pipe fittings on the flue of the furnace mouth section 1 constitute a low-pressure forced circulation system. The whole process is as follows: the deaerator 8 can be regarded as a steam drum of the low-pressure system, acting as a water distribution and steam collecting device of the low-pressure circulation system. The water from the deaerator 8 enters the charging sleeve 14, oxygen gun sleeve 15, and low-temperature evaporator 17 of the waste heat boiler 5 after passing through the low-pressure circulation pump, exchanges heat with the flue gas to form a steam-water mixture, and then returns to the deaerator 8; the low-pressure steam of the vaporization flue drum 7 and the external network can also be merged into the deaerator 8. The deaerator 8 has a built-in water tank, which can be regarded as a steam drum of the low-pressure system, and forms a low-pressure circulation loop with the low-pressure circulating water pump 10 and the charging sleeve 14 (or the oxygen gun sleeve 15, or the low-temperature evaporator 17 of the waste heat boiler 5). This design can reduce equipment and investment, and the actual operating pressure of the system is relatively low, which ensures the cooling effect and operating safety of the charging sleeve 14 and the oxygen gun sleeve 15, and reduces the heat exchange area of ​​the low-temperature evaporator 17 in the waste heat boiler 5.

[0045] Preferably, the flue gas waste heat recovery system further includes a heat accumulator 12, and the steam outlet of the vaporization flue steam drum 7 and the steam outlet of the waste heat pipeline are respectively connected to the heat accumulator 12 through steam delivery pipelines.

[0046] In the present invention, the heat accumulator 12 is a pressure-variable steam heat accumulator 12, which plays a role in stabilizing the load and balancing the peak and valley of steam supply. The vaporization flue drum 7, the waste heat boiler drum 6 and the heat accumulator 12 form a steam system.

[0047] In the utility model, the waste heat boiler 5 is a double-pressure boiler, and adopts a light tube as a heat exchange surface; the waste heat boiler 5 adopts a shock wave soot blowing system, and an ash discharge valve and an ash hopper 13 are arranged at the bottom of the waste heat boiler 5, and the dust in the tail flue gas falls into the ash hopper 13 of the waste heat boiler 5.

[0048] In the utility model, the vaporization flue drum 7 is used to collect the steam generated by the vaporization flue, and each AOD furnace is equipped with one; the vaporization flue drum 7 is a water distribution and steam collection device for medium-pressure forced circulation and natural circulation in the system, and its volume should basically meet the need for blowing a furnace of steel without replenishing water, ensuring that the converter can be blown smoothly and shut down safely when the water is cut off due to an accident. The vaporization flue drum 7 is equipped with a venting silencer, a safety valve, etc.; this is a conventional configuration. The waste heat boiler drum 6 is used to collect the steam generated by the medium-temperature evaporator 16 of the waste heat boiler 5.

[0049] The working principle of the utility model is:

[0050] After entering the deaerator 8 for deoxygenation, the desalted water is divided into three directions as cooling water: 1. It flows into the heat exchangers in each flue section (furnace mouth section 1, middle section 2 and tail section 3) of the vaporization flue through the vaporization flue drum 7; 2. It flows into the medium-temperature evaporator 16 and the low-temperature evaporator 17 of the waste heat boiler 5 through the waste heat boiler drum 6; 3. It flows into the charging jacket 14, the oxygen gun jacket 15 and the low-temperature evaporator 17 of the waste heat boiler 5 through the low-pressure circulating water pump 10;

[0051] The flue gas from the AOD furnace flows into the vaporization flue, exchanges heat with the cooling water in the vaporization flue charging jacket 14 and the oxygen gun jacket 15, and the cooling water in the heat exchange tube in the vaporization flue, and then flows into the waste heat boiler 5, exchanges heat with the cooling water in the medium temperature evaporator 16 and the low temperature evaporator 17 in the waste heat boiler 5, and then mixes into the secondary flue gas pipeline;

[0052] The cooling water in the charging sleeve 14 and the oxygen gun sleeve 15 exchanges heat with the flue gas to form a steam-water mixture, and then returns to the deaerator 8; the cooling water in the vaporization flue heat exchanger exchanges heat with the flue gas to form a steam-water mixture and then returns to the vaporization flue steam drum 7, the cooling water in the medium-temperature evaporator 16 and the low-temperature evaporator 17 of the waste heat boiler 5 exchanges heat with the flue gas to form a steam-water mixture and then returns to the waste heat boiler steam drum 6, and the steam separated from the vaporization flue steam drum 7 and the waste heat boiler steam drum 6 is collected and enters the heat accumulator 12 or the external steam main pipe.

[0053] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0054] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An AOD furnace flue gas waste heat recovery system, characterized in that: Including vaporization flue, vaporization flue drum, waste heat boiler, waste heat boiler drum and deaerator; The inlet of the vaporization flue is located above the AOD furnace; A heat exchanger is provided in the vaporization flue, the inlet of the heat exchanger is connected to the cooling water outlet of the vaporization flue drum through the first inlet pipeline A1, and the outlet of the heat exchanger is connected to the inlet of the vaporization flue drum through the first outlet pipeline B1; The waste heat boiler is provided with a flue inlet and a flue outlet, and the flue inlet of the waste heat boiler is connected with the outlet of the vaporization flue; A plurality of medium-temperature evaporators and a waste heat boiler automatic steam drum are arranged in the waste heat boiler; the medium-temperature evaporators are arranged in sequence along the flue gas flow direction, the inlet of each medium-temperature evaporator is connected to the outlet of the waste heat boiler steam drum through the second inlet pipeline, and the outlet of each medium-temperature evaporator is connected to the inlet of the waste heat boiler steam drum through the second outlet pipeline; The inlet of the deaerator is connected to the desalted water pipeline, the outlet of the deaerator is connected to the water inlet of the vaporization flue drum through the first water supply pipeline C1, and the outlet of the deaerator is connected to the water inlet of the waste heat boiler drum through the second water supply pipeline C2; The steam outlet of the vaporization flue drum and the steam outlet of the waste heat pipeline are respectively connected to the steam main pipe of the external network through the steam delivery pipeline.

2. The AOD furnace flue gas waste heat recovery system according to claim 1, characterized in that: The waste heat boiler is equipped with five medium-temperature evaporators and one low-temperature evaporator, wherein three medium-temperature evaporators are located at the flue gas inlet side; two medium-temperature evaporators and one low-temperature evaporator are located at the flue gas outlet side, and the low-temperature evaporator is located downstream of the two medium-temperature evaporators.

3. The AOD furnace flue gas waste heat recovery system according to claim 1, characterized in that: A water supply pump is arranged on the pipeline connected to the outlet of the deaerator, and the outlet of the water supply pump is communicated with the first water supply pipeline and the second water supply pipeline through pipelines respectively.

4. The AOD furnace flue gas waste heat recovery system according to claim 1, characterized in that: A medium-pressure circulating water pump is arranged on the pipeline (G1) connected to the outlet of the vaporization flue drum, and the outlet of the medium-pressure circulating pump is connected to the first inlet pipeline through the pipeline.

5. The AOD furnace flue gas waste heat recovery system according to claim 2, characterized in that: The vaporization flue comprises a furnace mouth section, a middle section and a tail section which are connected in sequence through an expansion compensator; the furnace mouth section is located directly above the AOD furnace, and is provided with an oxygen gun hole and a charging hole, and is equipped with an oxygen gun sleeve and a charging sleeve; the tail section is connected to the flue gas inlet of the waste heat boiler through the expansion compensator.

6. The AOD furnace flue gas waste heat recovery system according to claim 5, characterized in that: The furnace mouth section, middle section and tail section are respectively provided with manholes and hand holes.

7. The AOD furnace flue gas waste heat recovery system according to claim 5, characterized in that: The outlet of the deaerator is connected to an outlet pipeline F2, on which a low-pressure circulating water pump is arranged. The outlet of the low-pressure circulating water pump is connected to the cold source inlet of the charging sleeve, the cold source inlet of the oxygen gun sleeve, and the cold source inlet of the low-temperature evaporator of the waste heat boiler through pipelines; the cold source outlet of the charging sleeve, the cold source outlet of the oxygen gun sleeve, and the cold source outlet of the low-temperature evaporator of the waste heat boiler are connected to the inlet of the deaerator through a reflux pipeline.

8. The AOD furnace flue gas waste heat recovery and utilization system according to claim 5, characterized in that: The AOD furnace flue gas waste heat recovery system also includes a heat accumulator, and the steam outlet of the vaporization flue drum and the steam outlet of the waste heat pipeline are respectively connected to the heat accumulator through steam delivery pipelines.

9. The AOD furnace flue gas waste heat recovery system according to claim 8, characterized in that: The heat accumulator is a pressure variable steam heat accumulator.

10. The AOD furnace flue gas waste heat recovery and utilization system according to claim 8, characterized in that: An ash discharge valve and an ash hopper are arranged at the bottom of the waste heat boiler.

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