Total waste heat recovery, purification and emission system for primary flue gas of converter
By combining and designing a converter primary flue gas treatment system, the problems of temperature fluctuation, dust blockage and cost in the process of primary flue gas waste heat recovery have been solved, achieving full waste heat recovery and ultra-low emissions, and reducing system operating costs and equipment investment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2026-03-03
AI Technical Summary
The waste heat recovery process of primary flue gas from converters suffers from problems such as large temperature fluctuations, high dust content, easy clogging of heat exchangers, and high costs, which prevents existing systems from achieving full waste heat recovery and ultra-low emissions.
The system adopts a combined design of vaporization cooling flue, vaporization cooling flue extension, medium-temperature heat exchanger and low-temperature heat exchanger, combined with filter bag dust collector and gas switching station, to achieve full waste heat recovery and purified emission of flue gas. Large particulate dust is collected through header, the medium-temperature heat exchanger uses heat transfer oil medium, and the low-temperature heat exchanger is placed after the dust collector and before the fan. The dust is collected by pneumatic ash conveying.
It achieves full waste heat recovery of the primary flue gas of the converter, reduces system costs and power consumption, ensures heat exchange efficiency and ultra-low emissions, avoids the effects of dust deposition and temperature instability, and achieves energy saving and efficiency improvement.
Smart Images
Figure CN223963536U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of converter primary flue gas treatment technology, specifically relating to a converter primary flue gas full waste heat recovery and purification emission system. Background Technology
[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.
[0003] Converter primary flue gas refers to the high-temperature, dust-laden waste gas generated during oxygen blowing steelmaking in a converter (BOF) during the iron and steel smelting process. The primary flue gas originates from the violent reaction of oxygen with elements such as carbon, silicon, and manganese in the molten iron, producing gases such as CO and CO2, and carrying a large amount of iron oxide dust, with dust concentrations reaching 80-150 g / Nm³. 3 The temperature and flow rate of the primary flue gas in the converter flue gas exhibit significant fluctuations. In terms of temperature, the flue gas temperature can reach 1400-1600℃ during the blowing period, while the temperature drops sharply during the non-blowing period. In terms of flow rate, the flue gas flow rate changes drastically with the oxygen blowing, feeding, and other process stages, such as a sharp increase in flow rate during oxygen blowing.
[0004] Due to the aforementioned characteristics of converter primary flue gas, the following problems arise during waste heat recovery: 1. The flue gas temperature is high, typically requiring multi-stage heat exchangers to recover waste heat, which increases system costs; 2. The flue gas has a high dust content, necessitating the use of corresponding dust removal equipment in multi-stage heat exchangers. Without such equipment, dust will accumulate on the heat exchange tubes, forming an insulation layer and reducing heat exchange efficiency, potentially even clogging the entire flow channel; 3. Waste heat recovery systems typically use fans as the driving force. Due to the high temperature of the flue gas, high-temperature resistant flue gas is required, increasing costs. Furthermore, fan operation increases flue gas temperature, reducing the effective heat exchange temperature difference of the heat exchangers. Existing waste heat recovery systems do not consider these factors, making full waste heat recovery impossible. Utility Model Content
[0005] The purpose of this invention is to provide a converter primary flue gas full waste heat recovery and purification emission system, which can realize full waste heat recovery of flue gas, while avoiding the problems of discontinuous waste heat and poor heat exchange effect caused by intermittent heat sources, and improving the waste heat recovery and utilization rate.
[0006] To achieve the above objectives, this utility model is implemented through the following technical solution:
[0007] In a first aspect, embodiments of this utility model provide a converter primary flue gas waste heat recovery and purification emission system, comprising a converter, a vaporization cooling flue, a vaporization cooling flue extension section, a header, a medium-temperature heat exchanger, a bag filter dust collector, a low-temperature heat exchanger, a fan, and a gas switching station connected in sequence; the gas switching station includes a gas holder and a chimney, the gas holder is connected to the fan through a first pipeline, and the chimney is connected to the fan through a second pipeline, the first pipeline and the second pipeline being arranged in parallel.
[0008] As a further technical solution, the flue gas outlet of the converter is connected to the vaporization cooling flue, and the vaporization cooling flue is connected to the extension section of the vaporization cooling flue via a flange.
[0009] As a further technical solution, the top of the header is provided with a flue gas inlet and a flue gas outlet, and the bottom is provided with an ash outlet. The flue gas inlet is connected to the outlet of the extended section of the vaporization cooling flue, the flue gas outlet is connected to the medium-temperature heat exchanger, and the ash outlet is connected to the ash conveying system.
[0010] As a further technical solution, compensators are installed at both the flue gas inlet and flue gas outlet of the manifold.
[0011] As a further technical solution, multiple filter bag dust collectors are provided, and the multiple filter bag dust collectors are connected in parallel. The bottom of the filter bag dust collector is provided with an ash outlet, and the ash outlet is connected to the ash conveying system.
[0012] As a further technical solution, the inlets of multiple filter bag dust collectors are all connected to the main pipeline of raw coal gas through dust collector inlet branch pipes, and the main pipeline of raw coal gas is connected to a medium-temperature heat exchanger.
[0013] As a further technical solution, the outlets of multiple filter bag dust collectors are connected to the main clean gas pipeline through dust collector outlet branch pipes, and the main clean gas pipeline is connected to a low-temperature heat exchanger.
[0014] As a further technical solution, a recovery side cup valve is installed on the first pipeline, and a venting side cup valve is installed on the second pipeline.
[0015] As a further technical solution, a silencer is installed at the outlet of the fan.
[0016] As a further technical solution, the heat exchange medium used in the medium-temperature heat exchanger is heat transfer oil. When the flue gas is high-temperature flue gas during the blowing period, the medium-temperature heat exchanger absorbs heat; when the flue gas is not during the blowing period, the medium-temperature heat exchanger releases heat.
[0017] The beneficial effects of the above-described embodiments of this utility model are as follows:
[0018] (1) The converter primary flue gas full waste heat recovery and purification emission system provided by the present invention realizes full waste heat recovery of converter primary flue gas through the setting of vaporization cooling flue, vaporization cooling flue extension section, medium temperature heat exchanger and low temperature heat exchanger. The setting of vaporization cooling flue and vaporization cooling flue extension section can reduce the use of heat exchangers and reduce the cost of the system. At the same time, the medium temperature heat exchanger is set after the header and the low temperature heat exchanger is set after the filter bag dust collector, ensuring that the flue gas has been treated for dust removal before entering the heat exchanger, which can avoid the deposition of dust in the heat exchanger and affect the heat exchange efficiency.
[0019] (2) The present invention places the low-temperature heat exchanger in front of the fan after the dust collector. In this way, the problem of unstable low-temperature flue gas temperature and discontinuous waste heat caused by the periodic production of the converter can be effectively avoided. It can also reduce the total air volume of the fan, realize the full waste heat recovery of the primary flue gas of the converter, reduce the system operating cost and equipment investment cost, and truly achieve energy saving and efficiency improvement.
[0020] (3) The present invention uses a multi-stage heat exchange method to exchange the flue gas from about 900°C to below 70°C, which not only reduces the water consumption of the system, but also realizes the full waste heat recovery of the primary flue gas of the converter. By setting up a gas switching station, the flue gas can be recovered and released according to whether the gas meets the recovery conditions, thus realizing ultra-low carbon emissions of the flue gas. Conventional converter primary flue gas purification uses LT dry process or OG wet process, which cannot stably achieve ultra-low emissions of converter primary flue gas due to their process characteristics and efficiency.
[0021] (4) The present invention uses filter bag filtration to purify flue gas, which can not only stably achieve ultra-low emissions, but also eliminates the need for high-voltage power supply for LT dry process and high-resistance purification equipment for OG wet process, thus reducing the power consumption of the system; in addition, the dust is collected by pneumatic conveying, so there is no secondary pollution. Attached Figure Description
[0022] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.
[0023] Figure 1 This is a schematic diagram of the converter primary flue gas full waste heat recovery and purification emission system of this utility model.
[0024] The diagram is for illustrative purposes only.
[0025] The components are as follows: 1. Converter; 2. Gasification cooling flue; 3. Gasification cooling flue extension section; 4. Header; 5. Medium temperature heat exchanger; 6. Compensator; 7. Raw coal gas main pipeline; 8. Dust collector inlet branch pipe; 9. Bag filter dust collector; 10. Dust collector outlet branch pipe; 11. Clean coal gas main pipeline; 12. Low temperature heat exchanger; 13. Fan; 14. Silencer; 15. Recovery side cup valve; 16. Gas holder; 17. Venting side cup valve; 18. Chimney; 19. Coarse ash conveying system; 20. Coarse ash storage silo; 21. Fine ash pneumatic conveying system; 22. Fine ash storage silo. Detailed Implementation
[0026] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0027] Example 1
[0028] In a typical embodiment of this utility model, such as Figure 1 As shown, a converter primary flue gas waste heat recovery and purification emission system is provided, including a converter 1, a vaporization cooling flue 2, a vaporization cooling flue extension section 3, a header 4, a medium-temperature heat exchanger 5, a bag filter dust collector 9, a low-temperature heat exchanger 12, a fan 13, and a gas switching station connected in sequence; the gas switching station includes a gas holder 16 and a chimney 18, the gas holder 16 is connected to the fan 13 through a first pipeline, and the chimney 18 is connected to the fan 13 through a second pipeline, the first pipeline and the second pipeline are arranged in parallel.
[0029] The aforementioned system achieves full waste heat recovery from the primary flue gas of the converter through the inclusion of a vaporization cooling flue, an extended section of the vaporization cooling flue, a medium-temperature heat exchanger, and a low-temperature heat exchanger. The vaporization cooling flue and its extended section reduce the number of heat exchangers used, lowering system costs. Simultaneously, the medium-temperature heat exchanger is positioned after the header, and the low-temperature heat exchanger after the bag filter dust collector, ensuring that the flue gas undergoes dust removal before entering the heat exchangers, preventing dust accumulation and its impact on heat exchange efficiency. Placing the low-temperature heat exchanger after the dust collector and before the fan effectively avoids the problems of unstable low-temperature flue gas temperature and discontinuous waste heat recovery caused by the cyclical production of the converter. It also reduces the total fan air volume, achieving full waste heat recovery from the primary flue gas of the converter while lowering system operating costs and equipment investment costs, truly realizing energy saving and efficiency improvement.
[0030] In addition, considering that the fan usually generates a temperature rise of 5-15°C when it does work, by placing the fan after the low-temperature heat exchanger, it can be ensured that the temperature of the flue gas entering the low-temperature heat exchanger is the original flue gas temperature, rather than the temperature after being heated by the fan. The temperature rise generated by the fan will not affect the effective heat exchange temperature difference of the low-temperature heat exchanger, and the full waste heat recovery of the flue gas can be achieved.
[0031] In this embodiment, the flue gas outlet of the converter 1 is connected to the vaporization cooling flue 2. The vaporization cooling flue 2 is connected to the vaporization cooling flue extension section 3 via a flange. The primary flue gas of the converter first passes through the vaporization cooling flue for cooling and waste heat recovery, reducing the flue gas temperature from about 1450°C to about 900°C. Then, it is sent to the vaporization cooling flue extension section 3 for further cooling and waste heat recovery, reducing the flue gas temperature from about 900°C to 400°C to 500°C. By setting the vaporization cooling flue extension section 3, most of the waste heat of the flue gas can be recovered through the vaporization cooling flue. Since the vaporization cooling flue is vertically set and adopts a water-cooled wall tube bundle cooling method, even if the flue gas contains a lot of dust, the dust will not accumulate thickly on the water-cooled wall tube bundle due to gravity, thus minimizing the impact of dust on the heat exchange effect.
[0032] In this embodiment, the top of the manifold 4 is provided with a flue gas inlet and a flue gas outlet, and the bottom is provided with an ash outlet. The flue gas inlet is connected to the outlet of the vaporization cooling flue extension section 3, the flue gas outlet is connected to the medium-temperature heat exchanger 5, and the ash outlet is connected to the ash conveying system. By reducing the speed and changing the direction of the manifold 4, large dust particles in the flue gas are collected and sent to the coarse ash storage bin 20 for further processing by the coarse ash conveying system 19 at the bottom of the manifold 4. The collection of large dust particles by the manifold 4 serves to extinguish open flames and reduce the load on subsequent purification facilities. Compensators are provided at both the flue gas inlet and the flue gas outlet of the manifold. The compensators can freely expand and contract through their flexible structure (such as metal bellows or rubber material) to prevent thermal stress from being transferred to the flue and causing the flue to twist.
[0033] To accommodate the cyclical smelting of the converter, the intermediate-temperature heat exchanger uses thermal oil as the heat exchange medium. When the flue gas is high-temperature flue gas during the blowing period, the intermediate-temperature heat exchanger absorbs heat; when the flue gas is not during the blowing period, the intermediate-temperature heat exchanger releases heat to heat the flue gas, ensuring that the flue gas temperature is above the dew point temperature. The flue gas, after being treated in the header, enters the intermediate-temperature heat exchanger for further waste heat recovery, reducing the flue gas temperature from 400℃-500℃ to approximately 200℃, ensuring it remains above the dew point temperature.
[0034] In this embodiment, multiple bag filter dust collectors 9 are arranged in parallel. Each bag filter dust collector has an ash outlet at its bottom, which is connected to an ash conveying system. Furthermore, the inlets of all bag filter dust collectors 9 are connected to the main raw coal gas pipeline 7 via dust collector inlet branch pipes 8. The main raw coal gas pipeline 7 is connected to a medium-temperature heat exchanger 5. The outlets of all bag filter dust collectors 9 are connected to the main clean coal gas pipeline 11 via dust collector outlet branch pipes 10. The main clean coal gas pipeline 11 is connected to a low-temperature heat exchanger 12. The flue gas from the medium-temperature heat exchanger 5 enters the main raw coal gas pipeline 7 and is then fed into the bag filter dust collectors 9 via the dust collector inlet branch pipes 8 for filtration and purification. The purified flue gas is collected in the main clean coal gas pipeline 11 via the dust collector outlet branch pipes 10 and then sent to the low-temperature heat exchanger 12. The flue gas is collected by the bag filter dust collector 9 and then sent to the fine ash storage bin 22 through the fine ash pneumatic conveying system 21 at the bottom of the dust removal unit for storage and backup.
[0035] In this embodiment, a silencer 14 is provided at the outlet of the fan 13. The flue gas temperature is reduced from about 200°C to about 60°C by the low temperature heat exchanger 12 before entering the fan 13 and then entering the gas switching station through the silencer 14.
[0036] In this embodiment, a recovery-side cup valve 15 is installed on the first pipeline, and a venting-side cup valve 17 is installed on the second pipeline. When the gas is qualified and allowed to be recovered, it is sent to the gas holder 16 through the recovery-side cup valve 15. When the gas is unqualified or does not meet the conditions for recovery, it is sent to the chimney 18 for venting through the venting-side cup valve 17.
[0037] The working process of the converter primary flue gas waste heat recovery and purification emission system provided by this utility model is as follows:
[0038] The primary flue gas first undergoes heat exchange and cooling to approximately 900°C through a vaporization cooling flue. It then enters an extension section of the vaporization cooling flue for further cooling to 500°C-400°C. After cooling, the primary flue gas enters a header, where large dust particles settle before entering a medium-temperature heat exchanger for further waste heat recovery. The flue gas temperature is then reduced to 150°C-200°C before entering the raw coal gas pipeline. The primary flue gas then passes through the raw coal gas pipeline and the inlet branch of the dust collector into a bag filter for purification. The purified flue gas then passes through the outlet branch of the dust collector into the main clean coal gas pipe, and is then sent to a low-temperature heat exchanger for waste heat recovery. The flue gas temperature is reduced to below 60°C before entering the fan and passing through a silencer to the switching station.
[0039] When the gas is qualified and can be recycled, the flue gas is sent into the gas holder through the recycling cup valve; when the gas is unqualified or cannot be recycled, the flue gas is discharged into the atmosphere through the chimney through the vent cup valve.
[0040] The dust collected by the manifold in the system is sent to the coarse ash storage silo for storage and backup via the coarse ash conveying system at the bottom; the fine ash collected by the bag filter dust collector is finally sent to the fine ash storage silo for storage and backup via the fine ash pneumatic conveying system.
[0041] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A converter once flue gas full residual heat recovery and purification discharge system, characterized in that, The converter, the vaporization cooling flue, the vaporization cooling flue extension section, the header, the medium-temperature heat exchanger, the filter bag dust collector, the low-temperature heat exchanger, the fan and the gas switching station are sequentially connected.
2. The system for once-through flue gas total waste heat recovery and purification discharge of the converter according to claim 1, characterized in that, The flue gas outlet of the converter is connected with the vaporization cooling flue, and the vaporization cooling flue is connected with the vaporization cooling flue extension section through flanges.
3. The system for once-through flue gas total waste heat recovery and purification discharge of claim 1, wherein, The top of the header is provided with a flue gas inlet and a flue gas outlet, and the bottom is provided with an ash outlet.
4. The system for once-through flue gas total waste heat recovery and purification discharge of claim 3, wherein, Compensators are arranged at the flue gas inlet and the flue gas outlet of the header.
5. The system for once-through flue gas total residual heat recovery and purification discharge of claim 1, wherein, A plurality of filter bag dust collectors are arranged, and the filter bag dust collectors are connected in parallel.
6. The system for once-through flue gas total waste heat recovery and purification discharge of claim 5, wherein, The inlets of the filter bag dust collectors are connected with the main raw gas pipeline through dust collector inlet branch pipes.
7. The system for once-through flue gas total waste heat recovery and purification discharge of claim 5, wherein, The outlets of the filter bag dust collectors are connected with the main clean gas pipeline through dust collector outlet branch pipes.
8. The system for once-through flue gas total waste heat recovery and purification discharge of claim 1, wherein, A recovery side cup valve is arranged on the first pipeline, and a diffusion side cup valve is arranged on the second pipeline.
9. The system for once-through flue gas total residual heat recovery and purification discharge of claim 1, wherein, A muffler is arranged at the outlet of the fan.
10. The system for once-through flue gas total waste heat recovery and purification discharge of claim 1, wherein, The medium-temperature heat exchanger uses a heat-conducting oil medium, absorbs heat when the flue gas is high-temperature flue gas in the blowing period, and releases heat when the flue gas is not in the blowing period.