System and method for upgrading and utilizing medium-temperature and low-temperature waste gas in circular cooling

Abstract

The invention discloses a system and a method for upgrading and utilizing ring cooling medium and low temperature waste gas. The method comprises the following steps: sequentially carrying out heat and oxygen supplementation treatment, stepped heat exchange and selective split-flow steam supplementation treatment on sintering ring cold medium and low temperature waste gas to obtain oxygen-enriched hot waste gas and oxygen-enriched steam-enriched hot waste gas which can be directly used for sintering, and intermediate products such as high-parameter steam and industrial hot water; therefore, the waste heat of the sintering ring cooling medium-temperature and low-temperature waste gas is recovered at low cost and high efficiency, and meanwhile, the discharge amount of the waste gas is also remarkably reduced; and further, the oxygen-enriched hot waste gas and the oxygen-enriched steam-enriched hot waste gas are respectively returned to the sintering front-end material surface and the sintering rear-end material surface for oxygen-enriched hot air sintering and oxygen-enriched steam injection sintering, and the quality index of a sintered ore product is further improved.

Description

Technical Field

[0001] The invention relates to the treatment of sintering ring cooling waste gas, and in particular to a system and method for improving the quality of medium and low temperature waste gas from ring cooling, belonging to the technical field of sintering ring cooling waste gas treatment. Background Art

[0002] During the sintering process, the temperature of the sintered cake can reach 700-800℃ after being unloaded from the sintering machine. The physical sensible heat resources it carries are the most important part of the sintering waste heat resources. In the process of using air to cool the sintered ore, the temperature of the sintered ore drops below 150℃, and a large amount of hot air is generated. Generally, the temperature of the cooling exhaust gas in different parts of the sintering ring cooler is different. The temperature gradually decreases from the receiving end to the discharging end. It is generally divided into three sections: a high temperature zone with a temperature higher than 250℃, a medium temperature zone with a temperature of 150℃ to 250℃, and a low temperature zone with a temperature lower than 150℃.

[0003] In actual production, many enterprises have built supporting sintering waste heat recovery systems to utilize the high-temperature cooling waste gas of the ring cooler in the form of waste heat power generation. Due to the low temperature of the cooling waste gas in the medium and low temperature sections, the boiler heat exchange can only produce low-parameter steam, and the waste heat utilization efficiency is low and the utilization cost is high. Some enterprises even directly discharge it, which wastes resources and pollutes the environment. In addition, some enterprises return part of the flue gas in the ring cooler to the upper sealing cover of the sintering machine in the form of hot air sintering to improve the heat utilization rate of the ring cooling waste gas, hoping to reduce the emission of ring cooling flue gas while reducing sintering fuel consumption and improving the quality of sintered ore. For example, patent CN108731486A proposes a system and method for recycling medium and low temperature waste gas in an annular cooler, a smoke hood is set above the sintering machine and connected to the smoke hood above the annular cooler, and the medium and low temperature waste gas of 80℃~250℃ of the annular cooler is converted from being directly discharged into the atmosphere to being directly recycled into the bed of the sintering machine, thereby replacing the air originally inhaled from the surrounding atmosphere by the sintering machine for the sintering of raw and auxiliary fuels, so as to make full use of the sensible heat in the medium and low temperature waste gas and eliminate the pollution of the atmospheric environment by direct discharge of dust-containing waste gas. Patent CN106931792B proposes a method and device for comprehensive utilization of waste gas from annular cooler, wherein the medium temperature waste gas of 150-220℃ is used for ORC low temperature power generation through heat exchange, and the waste gas after utilization is used to return to the sintering process for hot air sintering, or it is mixed with the low temperature cooling waste gas of annular cooler of less than 150℃ to become waste gas of about 100℃, and returned to the sintering machine trolley for hot air sintering.

[0004] To sum up, in the existing technology, directly using the cooling exhaust gas from the medium and low temperature sections for boiler heat exchange can only produce low-parameter steam, and the waste heat preheating efficiency is low and the utilization cost is high. Returning the medium and low temperature exhaust gas to sintering instead of air can utilize the waste heat of the exhaust gas to a certain extent from an energy perspective. However, since the temperature of the cooling exhaust gas is much higher than that of air, the gas volume expansion causes the oxygen concentration to be much lower than that of air (about 310 mg / L), and the amount of oxygen drawn into the sintering material layer is reduced, which is not conducive to fuel combustion and affects the quality of sintered minerals. The exhaust gas must be cooled to about 100°C before returning to sintering, and the efficiency of utilizing the waste heat of the exhaust gas during the sintering process is low. Summary of the invention

[0005] In view of the problems in the prior art that direct waste heat recovery and utilization of medium and low-temperature exhaust gas from sintering ring cooling is inefficient and costly, and the temperature must be lowered when returning to sintering, resulting in low waste heat utilization efficiency, the present invention provides a system and method for improving the quality of medium and low-temperature exhaust gas from ring cooling. The system obtains oxygen-rich hot exhaust gas and oxygen-rich steam-rich hot exhaust gas that can be directly used for sintering, as well as intermediate products such as high-parameter steam and industrial hot water, by subjecting the medium and low-temperature exhaust gas from sintering ring cooling to heat and oxygen supplementation, step heat exchange, and selective diversion and steam supplementation treatment in sequence. The system and method further improve the sintering ore output and quality indicators by obtaining oxygen-rich hot exhaust gas and oxygen-rich steam-rich hot exhaust gas that can be directly used for sintering. The system thereby achieves low-cost and high-efficiency waste heat recovery of medium and low-temperature exhaust gas from sintering ring cooling, significantly reduces waste gas emissions, and further improves sintered ore output and quality indicators.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are specifically described as follows:

[0007] According to a first embodiment of the present invention, a system for improving the quality of low-temperature exhaust gas by ring cooling is provided:

[0008] A system for improving the quality and utilization of medium- and low-temperature waste gas from an annular cooling system, the system comprising a shell and an inner cavity. The bottom of the shell is provided with a waste gas inlet connected to the inner cavity. The inner cavity is divided from bottom to top into a heat and oxygen supplementation zone, a primary heat exchange zone, a secondary heat exchange zone, and a diversion and steam supplementation zone that are connected in series in sequence. The medium- and low-temperature waste gas from annular cooling system passes through the heat and oxygen supplementation zone, the primary heat exchange zone, the secondary heat exchange zone, and the diversion and steam supplementation zone in sequence and is converted into oxygen-rich hot waste gas and oxygen-rich steam-rich hot waste gas that can be directly used in the sintering process.

[0009] Preferably, the system also includes a sintering machine and a ring cooler. According to the direction of the sintering material: the front section smoke hood and the rear section smoke hood are sequentially covered on the sintering machine, and the first section wind hood, the second section wind hood and the third section wind hood are sequentially covered on the ring cooler. The air outlets of the second section wind hood and the third section wind hood are both connected to the exhaust gas inlet through the air inlet pipe. The oxygen-rich hot exhaust gas outlet of the split steam supply zone is connected to the air inlet of the front section smoke hood through the first circulating air supply pipe, and the oxygen-rich steam-rich hot exhaust gas outlet of the split steam supply zone is connected to the air inlet of the rear section smoke hood through the second circulating air supply pipe. Preferably, an electric gate valve is provided in the exhaust gas inlet.

[0010] Preferably, on the sintering machine: the area covered by the front fume hood is the 1 / 10 to 4 / 10 section of the material surface between the sintering ignition point and the sintering end point, and the area covered by the rear fume hood is the 5 / 10 to 8 / 10 section of the material surface between the sintering ignition point and the sintering end point.

[0011] Preferably, on the ring cooler: the air outlet of the three-stage air hood is first connected to the bottom air inlet of the second stage of the ring cooler located below the second-stage air hood through an air supply pipe, and the air outlet of the second-stage air hood is then connected to the exhaust gas inlet through an air inlet pipe.

[0012] Preferably, an oxygen-enriched burner is provided in the heat and oxygen supplementation zone, and a combustible gas pipeline and an oxygen-enriched gas pipeline are connected to the oxygen-enriched burner.

[0013] Preferably, a plurality of oxygen-enriched burners are arranged in the heat and oxygen supplementation zone, and each oxygen-enriched burner is independently connected to a combustible gas pipeline and an oxygen-enriched gas pipeline.

[0014] Preferably, a high-parameter steam superheater, a high-parameter steam evaporator, a high-parameter economizer, a deaerator evaporator and a low-parameter economizer are arranged in sequence from bottom to top in the primary heat exchange zone. A steam drum, a deaerator, a desalted water pipeline network and a steam power generation device are arranged outside the primary heat exchange zone. The front end of the high-parameter steam superheater is connected to the steam power generation device through a pipeline and a valve, and its rear end is connected to the steam drum through a pipeline. The front end and rear end of the high-parameter steam evaporator are both connected to the steam drum through a pipeline. The front end of the high-parameter economizer is connected to the deaerator through a pipeline, and its rear end is connected to the steam drum through a pipeline. The front end and rear end of the deaerator evaporator are both connected to the deaerator through a pipeline. The front end of the low-parameter economizer is connected to the desalted water pipeline network through a pipeline valve, and its rear end is connected to the deaerator through a pipeline.

[0015] Preferably, an industrial water heater is provided in the secondary heat exchange area, and an industrial water network and a hot water utilization pipeline are provided outside the secondary heat exchange area. The front end of the industrial water heater is connected to the industrial water network, and the rear end thereof is connected to the hot water utilization pipeline.

[0016] Preferably, a water mist nozzle and a diverter baffle are provided in the diverter steam supply area. The top of the diverter baffle is connected to the shell and divides the diverter steam supply area into two diverter chambers parallel in the horizontal direction. The water mist nozzle is provided in one of the diverter chambers, and an oxygen-rich steam-rich hot exhaust gas outlet is provided at the top of the diverter chamber, and an oxygen-rich hot exhaust gas outlet is provided at the top of the other diverter chamber. Preferably, the top of the diverter baffle is hinged to the shell so that the diverter baffle can swing in the horizontal direction to adjust the size of the two diverter chambers.

[0017] Preferably, according to the direction of the material, the annular cooler includes an annular cooling front section, an annular cooling middle section and an annular cooling rear section, and the bottom air inlet of the annular cooling front section and the bottom air inlet of the annular cooling rear section are independently connected to cooling fans, respectively. The bottom air inlet of the annular cooling middle section is provided with a blower.

[0018] According to a second embodiment of the present invention, a method for improving the quality of low-temperature waste gas from annular cooling is provided:

[0019] A method for upgrading and utilizing medium- and low-temperature waste gas from annular cooling or a method for upgrading and utilizing medium- and low-temperature waste gas from annular cooling using the system described in the first embodiment, the method comprising:

[0020] 1) Mix the ring-cooled medium-temperature exhaust gas and the ring-cooled low-temperature exhaust gas and perform supplementary heat and oxygen combustion to obtain oxygen-rich high-temperature hot flue gas.

[0021] 2) Use hot water to perform high-temperature heat exchange on the oxygen-rich high-temperature reheated flue gas to obtain high-parameter steam and oxygen-rich medium-temperature hot flue gas.

[0022] 3) Use cold water to perform low-temperature heat exchange on the oxygen-rich medium-temperature flue gas to obtain industrial hot water and oxygen-rich hot exhaust gas.

[0023] 4) Use water mist to atomize, control the temperature and add steam to part of the oxygen-rich hot exhaust gas to obtain oxygen-rich and steam-rich hot exhaust gas.

[0024] 5) The oxygen-rich hot waste gas and the oxygen-rich steam-rich hot waste gas are respectively sent to the sintering front section and the sintering back section of the sintering machine for sintering treatment.

[0025] Preferably, the ring-cooled low-temperature exhaust gas is first circulated as the cooling medium of the middle section of the ring-cooling, and the material is cooled and heat-exchanged to obtain the ring-cooled medium-temperature exhaust gas, and then the ring-cooled medium-temperature exhaust gas is supplemented with heat and oxygen to obtain oxygen-rich high-temperature hot flue gas.

[0026] Preferably, in step 1), the temperature of the annularly cooled low-temperature exhaust gas is lower than 150°C, preferably 110-150°C, and more preferably 120-145°C. The temperature of the annularly cooled medium-temperature exhaust gas is not lower than 150°C, preferably 160-250°C, and more preferably 170-240°C. The temperature of the oxygen-enriched high-temperature hot flue gas is not lower than 400°C, preferably 450-600°C, and more preferably 500-550°C. The oxygen concentration of the oxygen-enriched high-temperature hot flue gas is not lower than 140 mg / L, preferably 160-300 mg / L, and more preferably 180-260 mg / L.

[0027] Preferably, in step 2), the pressure of the high-parameter steam is not less than 1.5 MPa, preferably 1.8-3 MPa, more preferably 2-2.5 MPa. The temperature of the high-parameter steam is not less than 350°C, preferably 380-500°C, more preferably 400-480°C. The temperature of the oxygen-enriched warm flue gas is not higher than 200°C, preferably 160-190°C, more preferably 170-180°C.

[0028] Preferably, in step 3), the temperature of the oxygen-enriched hot exhaust gas is not higher than 160° C., preferably 130-155° C., more preferably 135-150° C. The oxygen concentration of the oxygen-enriched hot exhaust gas is not lower than 310 mg / L, preferably 320-400 mg / L, more preferably 330-380 mg / L.

[0029] Preferably, in step 4), the temperature of the oxygen-rich steam-rich hot exhaust gas is not higher than 150°C, preferably 120-145°C, and more preferably 130-140°C. The oxygen concentration of the oxygen-rich steam-rich hot exhaust gas is not less than 320 mg / L, preferably 330-420 mg / L, and more preferably 340-400 mg / L. The water vapor concentration of the oxygen-rich steam-rich hot exhaust gas is not less than 3wt%, preferably 3.2-5wt%, and more preferably 3.5-4.5wt%.

[0030] Preferably, in step 4), the oxygen-rich hot waste gas subjected to atomization, temperature control and steam addition treatment accounts for 30-55% of the total oxygen-rich hot waste gas, preferably 34-50%, and more preferably 38-48%.

[0031] Preferably, in step 4), the front section of sintering refers to the section of the material surface from 1 / 10 to 4 / 10 between the sintering ignition point and the sintering end point. The rear section of sintering refers to the section of the material surface from 5 / 10 to 8 / 10 between the sintering ignition point and the sintering end point.

[0032] In the present invention, the height of the shell is 1-300m, preferably 3-100m, more preferably 5-50m; the thickness of the shell is 1-100cm, preferably 1.5-60cm, more preferably 3-40cm. The heights of the supplementary heat and oxygen zone, the primary heat exchange zone, the secondary heat exchange zone and the split flow and supplementary steam zone in the vertical direction are the same or different.

[0033] In the present invention, in view of the problems in the prior art that the medium and low temperature waste gas of sintering ring cooling (the medium temperature waste gas of ring cooling discharged from the middle section of ring cooling and the low temperature waste gas of ring cooling discharged from the rear section of ring cooling) is difficult to be efficiently utilized, the present invention provides a waste gas quality improvement and conversion mechanism with a heat and oxygen supplementation zone, a primary heat exchange zone, a secondary heat exchange zone, and a shunt steam supplementation zone to supplement oxygen and heat the medium and low temperature waste gas of ring cooling to obtain oxygen-rich high temperature hot flue gas. The oxygen-rich high temperature hot flue gas can directly undergo step heat exchange to obtain high-parameter hot steam for power generation, and then undergo shunt steam supplementation treatment to obtain oxygen-rich hot waste gas and oxygen-rich steam-rich hot waste gas that can be directly used for sintering. In other words, the present invention realizes the efficient utilization of the medium and low temperature waste gas of sintering ring cooling through the quality improvement and conversion mechanism, and also realizes the full quality consumption of the waste gas without the emission of excess waste gas.

[0034] In the present invention, the high-temperature exhaust gas from sintering ring cooling (the exhaust gas discharged from the front stage of ring cooling) can be directly utilized as waste heat because of its high temperature (the wind temperature is generally >250°C), for example, it can be transported to a preheating boiler to produce high-parameter steam and used for power generation or other metallurgical processes.

[0035] In the present invention, the low-temperature waste gas from the ring cooling can be used as the cooling medium of the middle section of the ring cooling through the air supply pipe, and the material can be cooled and heat-exchanged upward to obtain the medium-temperature waste gas from the ring cooling, and then the medium-temperature waste gas from the ring cooling can be sent to the quality-improving conversion mechanism for quality-improving conversion treatment; that is, the low-temperature waste gas (temperature <150°C) discharged from the rear section of the ring cooling machine can be circulated to the cooling air inlet of the middle section of the ring cooling machine to completely or partially replace the cold air as the cooling air of the middle section of the ring cooling machine to cool the sintered material. By recycling the low-temperature waste gas, on the one hand, the direct discharge of the low-temperature waste gas can be completely avoided, and the temperature of the medium-temperature waste gas discharged from the middle section of the ring cooling with an original temperature between 150°C and 250°C can be increased to 200°C to 300°C, so as to achieve the enrichment of the sensible heat of the material, which is beneficial to the efficient recovery of subsequent heat. On the other hand, by completely or partially replacing the cold air entering the middle section of the ring cooling, the total amount of cold air used for cooling by the ring cooler is significantly reduced, and then the output of hot waste gas is significantly reduced, and finally the heat discharged with the waste gas is also significantly reduced.

[0036] In the present invention, although the temperature of the medium-temperature exhaust gas discharged from the middle section of the ring cooling is higher than that of the exhaust gas in the traditional process, the direct use of the medium-temperature exhaust gas still has the disadvantage that the wind temperature is relatively low, which makes the waste heat utilization efficiency relatively low (that is, it is difficult to exchange heat with industrial hot water to obtain high-parameter steam). Therefore, the medium-temperature exhaust gas is transported to the heat supplement and oxygen supplement area for oxygen-enriched combustion to achieve oxygen supplement and heat supplement. The heat supplement and oxygen supplement area generally uses low-value combustible gas (such as blast furnace gas, converter gas, etc.) Low-value gas is easy to obtain in steel plants, which can achieve self-sufficiency, and also makes this part of the low-value gas also obtain Full recycling and utilization; when necessary, high-value fuel or gas can also be used, but the relative cost will be higher) with oxygen-enriched gas for combustion, supplementing oxygen-enriched gas (excess oxygen), on the one hand, is conducive to promoting the full combustion of low-value combustible gas, thereby increasing the flue gas temperature, and on the other hand, it can increase the oxygen concentration in the flue gas, that is, while realizing the supplementary heat of the medium and low temperature exhaust gas of the sintering ring cooling, the oxygen concentration is simultaneously increased. After oxygen-enriched combustion, the medium and low temperature exhaust gas is converted into oxygen-enriched high-temperature hot flue gas with a temperature of more than 400°C and an oxygen concentration of more than 140 mg / L. In other words, by reheating the medium and low temperature exhaust gas with oxygen enrichment, the medium and low temperature exhaust gas that is difficult to directly utilize is converted into oxygen-enriched high-temperature hot flue gas that is easy to directly utilize, and at the same time, the efficient recycling and utilization of low-value combustible gas in the plant area is realized.

[0037] In the present invention, a step-by-step heat exchange method (high-temperature heat exchange in the primary heat exchange zone and low-temperature heat exchange in the secondary heat exchange zone) is adopted to realize the efficient recovery and utilization of oxygen-rich high-temperature hot flue gas, that is, the oxygen-rich high-temperature hot flue gas passes through the primary heat exchange zone in turn for high-temperature indirect heat exchange, enters the secondary heat exchange zone for secondary low-temperature indirect heat exchange, and enters the diversion steam supply zone for diversion atomization, temperature control, cooling and homogenization, thereby generating high-quality steam, industrial hot water, and oxygen-rich hot waste gas and oxygen-rich steam-rich hot waste gas that can be directly reused for sintering. Specifically, the oxygen-rich high-temperature hot flue gas is firstly heat-exchanged with industrial hot water in the primary heat exchange zone to produce high-parameter steam with a pressure of ≥1.5MPa and a temperature of ≥350℃ for power generation, and the flue gas temperature at the outlet of the primary heat exchange zone is reduced to 160℃~200℃ (oxygen-rich medium-temperature hot flue gas); then the oxygen-rich medium-temperature hot flue gas is heat-exchanged with normal temperature water (industrial water) in the secondary heat exchange zone to produce industrial hot water with a temperature of ≥90℃. The industrial hot water can be reused in the primary heat exchange zone to exchange heat with the oxygen-rich high-temperature hot flue gas to produce high-quality steam or for sintering. In the mining production process, the flue gas temperature at the outlet of the secondary heat exchange zone is reduced to 130-160°C (oxygen-rich hot exhaust gas); finally, part (for example, 30%-55%) of the oxygen-rich hot exhaust gas is sprayed with atomized water for heat exchange cooling in the diversion steam supply zone to further reduce the flue gas temperature. At the same time, the atomized water absorbs heat and vaporizes into water vapor, and finally produces oxygen-rich steam-rich hot exhaust gas with a temperature of 120°C-155°C, an oxygen concentration of 320mg / L-420mg / L, and a water vapor concentration of 3%-5%, which can be directly sintered and reused. In other words, the present invention realizes the efficient step-by-step utilization of oxygen-rich high-temperature hot flue gas by means of stepped heat exchange, and obtains multi-stage products that can be directly recycled internally, realizing the complete consumption and utilization of oxygen-rich high-temperature hot flue gas without waste gas emissions.

[0038] In the present invention, oxygen-enriched hot waste gas and oxygen-enriched steam-enriched hot waste gas are respectively sent to the sintering front section and sintering back section of the sintering machine through a circulating gas pipe to replace the normal temperature air and enter the sintering material layer to promote the sintering reaction. Among them, the sintering front section refers to the section where the 1 / 10 to 4 / 10 section of the material surface is located between the sintering ignition point and the sintering end point; the sintering back section refers to the section where the 5 / 10 to 8 / 10 section of the material surface is located between the sintering ignition point and the sintering end point. The oxygen-enriched hot waste gas is directly returned to the sintering front section material surface for hot air sintering, which increases the upper limit of the hot air allowable temperature and realizes oxygen-enriched sintering, optimizes the sintering reaction process in the front and middle ends of sintering, and improves the quality indicators of sintered minerals; and the oxygen-enriched steam-enriched hot waste gas is directly returned to the sintering back section material surface for oxygen-enriched steam injection sintering, which optimizes the sintering reaction process in the middle and rear ends of sintering and improves the quality of sintered minerals.

[0039] In the present invention, an oxygen-enriched burner is provided in the heat and oxygen supply zone to increase the temperature and oxygen concentration of the low-temperature exhaust gas in the annular cooling system. The burner can be an independent heat and oxygen supply burner or an oxygen-enriched combustion burner. The upper end of the heat and oxygen supply zone is connected to the lower end of the primary heat exchange zone.

[0040] In the present invention, a high-parameter steam superheater, a high-parameter steam evaporator, a high-parameter economizer, a deaerator evaporator and a low-parameter economizer are arranged in sequence from bottom to top in the primary heat exchange zone, and a steam drum, a deaerator, a desalted water pipeline network and a steam power generation device are arranged on the outside thereof. The oxygen-rich high-temperature hot flue gas from the heat and oxygen supply zone is indirectly heat exchanged with the industrial hot water sent to the primary heat exchange zone. The industrial hot water absorbs the heat carried by the oxygen-rich high-temperature hot flue gas and is converted into high-parameter steam for power generation; the oxygen-rich high-temperature hot flue gas is converted into oxygen-rich medium-temperature hot flue gas and enters the secondary heat exchange zone upward.

[0041] In the present invention, an industrial water heater is arranged in the secondary heat exchange area, and the industrial water heater is connected to the industrial water pipe network arranged outside. The industrial water pipe network sends industrial cold water (ambient temperature) into the industrial water heater for indirect heat exchange with the oxygen-rich medium-temperature hot flue gas from the primary heat exchange area. The industrial cold water absorbs heat to generate industrial hot water and supplies it to the primary heat exchange area and the sintering production process; the oxygen-rich medium-temperature hot flue gas is converted into oxygen-rich hot exhaust gas after heat exchange and cooling, and enters the split steam supply area upward.

[0042] In the present invention, a water mist nozzle and a diverter baffle are provided in the diverter steam supply area. The top end of the diverter baffle is connected to the shell and divides the diverter steam supply area into two diverter chambers parallel in the horizontal direction. The diverter baffle can swing between the two diverter chambers to adjust the amount of oxygen-rich hot exhaust gas from the secondary heat exchange area entering the two diverter chambers (for example, the ratio of the air intake volume of the left diverter chamber to the right diverter chamber is 30-55%: 45-70%). In one of the diverter chambers (such as Figure 1 A water mist nozzle is provided in the left diversion chamber in the sintering process to spray water mist on the oxygen-rich hot exhaust gas entering the diversion chamber, thereby lowering the exhaust gas temperature and increasing the concentration of water vapor in the exhaust gas, thereby obtaining oxygen-rich and steam-rich hot exhaust gas that can be directly reused for sintering.

[0043] In the present invention, the system and method of the present invention adopt technical means such as cascade utilization of low-temperature exhaust gas from comprehensive sintering ring cooling, simultaneous heat and oxygen supplementation for medium-temperature exhaust gas to improve quality, and cascade heat exchange and steam enrichment to eliminate direct emission of low-temperature exhaust gas, and then use low-value coal gas combustion in the steel plant to supplement heat and coordinate oxygen supplementation or oxygen-enriched combustion to increase the temperature of medium and low-temperature exhaust gases to meet the requirements for producing high-parameter steam while significantly increasing the oxygen content in the exhaust gas. After heat exchange to produce high-quality steam and industrial hot water, selective diversion water mist is used to further control the flue gas temperature, thereby achieving the purpose of containing a certain amount of water vapor in the exhaust gas. By taking the above technical measures, firstly, the recovery of waste heat from medium and low temperature exhaust gas in sintering ring cooling is transformed from direct discharge or recovery of low parameter steam to recovery of high parameter steam, and the quality and efficiency of waste heat recovery are improved; secondly, oxygen and steam are added to the medium and low temperature exhaust gas while replenishing heat, so as to increase the oxygen concentration in the exhaust gas finally returned to sintering (≥310mg / L of oxygen concentration in air at normal temperature), so that when the exhaust gas temperature entering sintering is greater than 120℃, its oxygen content can still meet the needs of sintering reaction, eliminating the effect of thin oxygen at high temperature on sintering. The negative impact of the process is reduced, and the utilization rate of waste heat from exhaust gas in the sintering process is improved; thirdly, the oxygen-rich hot exhaust gas and the oxygen-rich steam-rich hot exhaust gas are selectively returned to the exhaust gas at the front and rear stages of sintering to carry out oxygen-rich hot air sintering and oxygen-rich steam blowing sintering. Compared with ordinary air, it contains both excess oxygen and part of steam. The improvement effects of the existing "oxygen-enriched sintering technology" and "surface steam injection technology" on sintering are superimposed. When this exhaust gas is used to replace air for sintering, the quality indicators of sintered minerals can be significantly improved and pollutant emissions can be reduced.

[0044] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0045] 1: The system and method provided by the present invention realizes the recovery of waste heat of medium and low temperature exhaust gas in sintering ring cooling, which is transformed from direct emission or recovery of low-parameter steam to recovery of high-parameter steam, with zero exhaust gas emission, and significantly improves the quality and efficiency of waste heat recovery; at the same time, oxygen is added to the medium and low temperature exhaust gas while replenishing heat, thereby increasing the oxygen concentration in the exhaust gas finally returned to sintering, and when the exhaust gas temperature is greater than 120°C, the oxygen content of the exhaust gas entering the sintering material layer can still meet the reaction requirements, eliminating the negative impact of thin oxygen at high temperature on the sintering process, and improving the utilization rate of waste heat of the sintering process; in addition, oxygen-rich hot exhaust gas and oxygen-rich steam-rich hot exhaust gas can be generated respectively, which are returned to the front end material surface and the rear end material surface of sintering for oxygen-rich hot air sintering and oxygen-rich steam blowing sintering respectively, thereby improving the quality of sintered minerals and reducing pollutant emissions.

[0046] 2: The system and method provided by the present invention integrates units such as heat supplement, oxygen enrichment, temperature control, and steam injection, and comprehensively utilizes the positive effects of technical means such as cascade utilization of low-temperature exhaust gas from sintering ring cooling, simultaneous heat supplement and oxygen supplementation for quality improvement of medium-temperature exhaust gas, and cascade heat exchange and steam enrichment, thereby greatly improving the waste heat utilization efficiency of low-temperature exhaust gas from the ring cooler and reducing exhaust gas emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the structure of the system for improving the quality of low-temperature exhaust gas by ring cooling according to the present invention.

[0048] Figure 2 It is a schematic structural diagram of the system of the present invention when it has a sintering machine and a ring cooler.

[0049] Figure 3 It is a schematic flow chart of the method for improving the quality and utilizing the ring-cooled medium and low temperature waste gas of the present invention.

[0050] Figure numerals: 1: exhaust gas inlet; 101: electric gate valve; 2: supplementary heat and oxygen zone; 201: oxygen-enriched burner; 202: combustible gas pipeline; 203: oxygen-enriched oxygen pipeline; 3: primary heat exchange zone; 301: high-parameter steam superheater; 302: high-parameter steam evaporator; 303: high-parameter economizer; 304: deaerator evaporator; 305: low-parameter economizer; 306: steam drum; 307: deaerator; 308: desalted water pipeline network; 309: pipeline valve ; 310: steam power generation device; 4: secondary heat exchange area; 401: industrial water heater; 402: industrial water network; 403: hot water utilization pipeline; 5: diversion steam supply area; 501: water mist nozzle; 502: diversion baffle; 503: first circulation gas pipeline; 504: second circulation gas pipeline; 6: sintering machine; 601: front section smoke hood; 602: rear section smoke hood; 7: ring cooler; 701: first section wind hood; 702: second section wind hood; 703: third section wind hood. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is illustrated below by way of example, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0052] A system for improving the quality of low-temperature waste gas from annular cooling, the system comprising a shell and an inner cavity. The bottom of the shell is provided with a waste gas inlet 1 connected to the inner cavity. The inner cavity is divided from bottom to top into a heat and oxygen supplementation zone 2, a primary heat exchange zone 3, a secondary heat exchange zone 4, and a diversion and steam supplementation zone 5 which are connected in series in sequence. The low-temperature waste gas from annular cooling passes through the heat and oxygen supplementation zone 2, the primary heat exchange zone 3, the secondary heat exchange zone 4, and the diversion and steam supplementation zone 5 in sequence and is converted into oxygen-rich hot waste gas and oxygen-rich steam-rich hot waste gas which can be directly used in the sintering process.

[0053] Preferably, the system also includes a sintering machine 6 and an annular cooler 7. According to the direction of the sintering material: a front-stage smoke hood 601 and a rear-stage smoke hood 602 are sequentially covered on the sintering machine 6, and a first-stage wind hood 701, a second-stage wind hood 702 and a third-stage wind hood 703 are sequentially covered on the annular cooler 7. The air outlets of the second-stage wind hood 702 and the third-stage wind hood 703 are both connected to the exhaust gas inlet 1 through the air inlet pipe. The oxygen-rich hot exhaust gas outlet of the split steam-supplementing zone 5 is connected to the air inlet of the front-stage smoke hood 601 through the first circulating air pipe 503, and the oxygen-rich steam-rich hot exhaust gas outlet of the split steam-supplementing zone 5 is connected to the air inlet of the rear-stage smoke hood 602 through the second circulating air pipe 504. Preferably, an electric gate valve 101 is provided in the exhaust gas inlet 1.

[0054] Preferably, on the sintering machine: the front smoke hood 601 covers the 1 / 10 to 4 / 10 section of the material surface between the sintering ignition point and the sintering end point, and the rear smoke hood 602 covers the 5 / 10 to 8 / 10 section of the material surface between the sintering ignition point and the sintering end point.

[0055] Preferably, on the ring cooler: the air outlet of the three-stage air hood 703 is first connected to the bottom air inlet of the second stage of the ring cooler located below the second-stage air hood 702 through an air supply pipe, and the air outlet of the second-stage air hood 702 is then connected to the exhaust gas inlet 1 through an air inlet pipe.

[0056] Preferably, an oxygen-enriched burner 201 is provided in the heat and oxygen supplementation zone 2 , and a combustible gas pipeline 202 and an oxygen-enriched gas pipeline 203 are connected to the oxygen-enriched burner 201 .

[0057] Preferably, a plurality of oxygen-enriched burners 201 are provided in the heat and oxygen supplementation zone 2, and each oxygen-enriched burner 201 is independently connected to a combustible gas pipeline 202 and an oxygen-enriched gas pipeline 203.

[0058] Preferably, a high-parameter steam superheater 301, a high-parameter steam evaporator 302, a high-parameter economizer 303, a deaerator evaporator 304 and a low-parameter economizer 305 are sequentially arranged in the first-level heat exchange zone 3 from bottom to top. A steam drum 306, a deaerator 307, a desalted water pipe network 308 and a steam power generation device 310 are arranged outside the first-level heat exchange zone 3. The front end of the high-parameter steam superheater 301 is connected to the steam power generation device 310 through a pipeline and a valve, and the rear end thereof is connected to the steam drum 306 through a pipeline. The front end and the rear end of the high-parameter steam evaporator 302 are both connected to the steam drum 306 through a pipeline. The front end of the high-parameter economizer 303 is connected to the deaerator 307 through a pipeline, and the rear end thereof is connected to the steam drum 306 through a pipeline. The front end and the rear end of the deaerator evaporator 304 are both connected to the deaerator 307 through a pipeline. The front end of the low parameter economizer 305 is connected to the demineralized water network 308 through a pipeline valve 309 , and the rear end thereof is connected to the deaerator 307 through a pipeline.

[0059] Preferably, an industrial water heater 401 is provided in the secondary heat exchange area 4, and an industrial water network 402 and a hot water utilization pipeline 403 are provided outside the secondary heat exchange area 4. The front end of the industrial water heater 401 is connected to the industrial water network 402, and the rear end thereof is connected to the hot water utilization pipeline 403.

[0060] Preferably, a water mist nozzle 501 and a diverter baffle 502 are provided in the diverter and in-steam zone 5. The top of the diverter baffle 502 is connected to the shell and divides the diverter and in-steam zone 5 into two diverter chambers parallel in the horizontal direction. The water mist nozzle 501 is provided in one of the diverter chambers, and an oxygen-rich steam-rich hot exhaust gas outlet is provided at the top of the diverter chamber, while an oxygen-rich hot exhaust gas outlet is provided at the top of the other diverter chamber. Preferably, the top of the diverter baffle 502 is hinged to the shell, so that the diverter baffle 502 can swing in the horizontal direction to adjust the size of the two diverter chambers.

[0061] Example 1

[0062] like Figure 1-2 As shown, a system for upgrading and utilizing the medium and low temperature waste gas of annular cooling includes a shell and an inner cavity. The bottom of the shell is provided with a waste gas inlet 1 connected to the inner cavity. The inner cavity is divided from bottom to top into a heat supplement and oxygen supplement area 2, a primary heat exchange area 3, a secondary heat exchange area 4, and a diversion and supplementary steam area 5 which are connected in series in sequence. The medium and low temperature waste gas of annular cooling passes through the heat supplement and oxygen supplement area 2, the primary heat exchange area 3, the secondary heat exchange area 4, and the diversion and supplementary steam area 5 in sequence and is converted into oxygen-rich hot waste gas and oxygen-rich steam-rich hot waste gas which can be directly used in the sintering process.

[0063] Example 2

[0064] Example 1 is repeated, except that the system further includes a sintering machine 6 and an annular cooler 7. According to the direction of the sintering material: a front section smoke hood 601 and a rear section smoke hood 602 are sequentially provided on the sintering machine 6, and a first section wind hood 701, a second section wind hood 702 and a third section wind hood 703 are sequentially provided on the annular cooler 7. The air outlets of the second section wind hood 702 and the third section wind hood 703 are both connected to the exhaust gas inlet 1 through the air inlet pipe. The oxygen-rich hot exhaust gas outlet of the split steam supply area 5 is connected to the air inlet of the front section smoke hood 601 through the first circulating air supply pipe 503, and the oxygen-rich steam-rich hot exhaust gas outlet of the split steam supply area 5 is connected to the air inlet of the rear section smoke hood 602 through the second circulating air supply pipe 504.

[0065] Example 3

[0066] The second embodiment is repeated except that an electric gate valve 101 is provided in the exhaust gas inlet 1 .

[0067] Example 4

[0068] Example 3 is repeated, except that on the sintering machine: the front smoke hood 601 covers the area from 1 / 10 to 4 / 10 of the material surface between the sintering ignition point and the sintering end point, and the rear smoke hood 602 covers the area from 5 / 10 to 8 / 10 of the material surface between the sintering ignition point and the sintering end point.

[0069] Example 5

[0070] Repeat Example 4, except that on the ring cooler: the air outlet of the three-stage air hood 703 is first connected to the bottom air inlet of the second stage of the ring cooler located below the two-stage air hood 702 through the air supply pipe, and the air outlet of the two-stage air hood 702 is then connected to the exhaust gas inlet 1 through the air inlet pipe.

[0071] Example 6

[0072] Example 5 is repeated, except that an oxygen-enriched burner 201 is provided in the heat and oxygen supplementation zone 2, and a combustible gas pipeline 202 and an oxygen-enriched gas pipeline 203 are connected to the oxygen-enriched burner 201.

[0073] Example 7

[0074] Example 6 is repeated, except that a plurality of oxygen-enriched burners 201 are provided in the heat and oxygen supplementation zone 2, and each oxygen-enriched burner 201 is independently connected to a combustible gas pipeline 202 and an oxygen-enriched gas pipeline 203.

[0075] Example 8

[0076] Example 7 is repeated, except that a high-parameter steam superheater 301, a high-parameter steam evaporator 302, a high-parameter economizer 303, a deaerator evaporator 304 and a low-parameter economizer 305 are arranged in order from bottom to top in the primary heat exchange zone 3. A steam drum 306, a deaerator 307, a desalted water pipe network 308 and a steam power generation device 310 are arranged outside the primary heat exchange zone 3. The front end of the high-parameter steam superheater 301 is connected to the steam power generation device 310 through a pipeline and a valve, and the rear end thereof is connected to the steam drum 306 through a pipeline. The front end and the rear end of the high-parameter steam evaporator 302 are both connected to the steam drum 306 through a pipeline. The front end of the high-parameter economizer 303 is connected to the deaerator 307 through a pipeline, and the rear end thereof is connected to the steam drum 306 through a pipeline. The front end and the rear end of the deaerator evaporator 304 are both connected to the deaerator 307 through a pipeline. The front end of the low parameter economizer 305 is connected to the demineralized water network 308 through a pipeline valve 309 , and the rear end thereof is connected to the deaerator 307 through a pipeline.

[0077] Example 9

[0078] Example 8 is repeated, except that an industrial water heater 401 is provided in the secondary heat exchange area 4, and an industrial water network 402 and a hot water utilization pipeline 403 are provided outside the secondary heat exchange area 4. The front end of the industrial water heater 401 is connected to the industrial water network 402, and the rear end thereof is connected to the hot water utilization pipeline 403.

[0079] Example 10

[0080] Example 9 is repeated, except that a water mist nozzle 501 and a flow divider baffle 502 are provided in the flow divider and in-steam zone 5. The top end of the flow divider baffle 502 is connected to the shell and divides the flow divider and in-steam zone 5 into two flow divider chambers parallel in the horizontal direction. The water mist nozzle 501 is provided in one of the flow divider chambers, and an oxygen-rich steam-rich hot exhaust gas outlet is provided at the top of the flow divider chamber, and an oxygen-rich hot exhaust gas outlet is provided at the top of the other flow divider chamber.

[0081] Embodiment 11

[0082] Example 10 is repeated, except that the top end of the diverter baffle 502 is hinged to the shell, so that the diverter baffle 502 can swing in the horizontal direction to adjust the size of the two diverter chambers.

[0083] Example 12

[0084] The system described in Example 11 is used to improve the quality of the medium and low temperature waste gas of the ring cooling:

[0085] The mixed waste gas (temperature of about 175°C and oxygen concentration of about 206 mg / L) from the low-temperature cooling section of the sintering ring cooler is introduced into the supplementary heat and oxygen zone, where coal gas and oxygen are used for oxygen-enriched combustion to increase the waste gas temperature to 486°C (under the condition of only increasing the temperature, the oxygen concentration is about 122 mg / L), and the oxygen concentration is increased to about 199 mg / L to obtain oxygen-enriched high-temperature hot flue gas; the oxygen-enriched high-temperature hot flue gas is passed upward through the primary heat exchange zone and the secondary heat exchange zone in sequence, and is converted into oxygen-enriched hot waste gas with a temperature of about 155°C and an oxygen concentration of about 352 mg / L; in this process, a flow rate of 49 t / h, a pressure of about 1.8 MPa, and a temperature of about 392°C are generated. High-parameter steam is used for power generation, and hot water with a flow rate of 50t / h and a temperature of about 90°C is generated and returned to the sintering process for use; then the angle of the diverter baffle is adjusted to allow about 40% of the oxygen-rich hot exhaust gas to enter the atomizing and steaming zone (left diverter chamber) for water mist spraying and transform into oxygen-rich steam-rich hot exhaust gas with a temperature of about 140°C, an oxygen concentration of about 365mg / L, and a water vapor content of about 3.7%; the oxygen-rich steam-rich hot exhaust gas is returned to the 5 / 10-8 / 10 section of the material surface between the ignition point of the sintering machine and the end point of sintering for oxygen-rich steam blowing sintering, and the remaining 60% of the oxygen-rich hot exhaust gas is returned to the 1 / 10 to 4 / 10 section of the material surface between the ignition point of the sintering machine and the end point of sintering for oxygen-rich hot air sintering. Compared with conventional processes, the medium and low temperature waste heat exhaust gas is used in the form of waste heat power generation after quality improvement. At the same time, the hot air temperature of the material surface in the front stage of sintering is increased from about 100℃ to 140-155℃, the overall utilization rate of the waste heat of the sintering ring cooling exhaust gas is increased by 28%, the sintering ore return rate is reduced by 1.2%, the sintering ore drum strength is increased by 2.1%, and the sintering utilization coefficient is increased by 0.034t / m 2 ·h -1 , solid fuel consumption decreased by 1.51kg / t, and CO concentration in sintering flue gas decreased by 1272ppm.

[0086] Embodiment 13

[0087] The system described in Example 11 is used to improve the quality of the medium and low temperature waste gas of the ring cooling:

[0088] First, the low-temperature exhaust gas (about 142°C) discharged from the rear section of the ring cooler is circulated back to the air inlet of the middle section of the ring cooler through the pipeline as a cooling medium to cool the medium-temperature material and produce medium-temperature exhaust gas with a temperature of about 251°C and an oxygen concentration of about 176 mg / L; then the medium-temperature exhaust gas is introduced into the supplementary heat and oxygen zone, where coal gas and oxygen are used for oxygen-enriched combustion to increase the exhaust gas temperature to 522°C (under the condition of only increasing the temperature, the oxygen concentration is about 116 mg / L), and the oxygen concentration is increased to 181 mg / L to obtain oxygen-enriched high-temperature hot flue gas; the oxygen-enriched high-temperature hot flue gas is passed upward through the primary heat exchange zone and the secondary heat exchange zone in sequence, and is converted into oxygen-enriched hot exhaust gas with a temperature of about 141°C and an oxygen concentration of about 368 mg / L; in this process, a flow rate of 5 0.5t / h, high-parameter steam with a pressure of about 2.3MPa and a temperature of about 416℃ is used for power generation, and hot water with a flow rate of 50t / h and a temperature of about 90℃ is generated and returned to the sintering process for use; then the angle of the diverter baffle is adjusted to allow about 45% of the oxygen-enriched hot exhaust gas to enter the atomizing and steaming area (the left diverter chamber) for water mist spraying and transform into oxygen-enriched steam-rich hot exhaust gas with a temperature of about 133℃, an oxygen concentration of about 378mg / L and a water vapor content of about 4%; the oxygen-enriched steam-rich hot exhaust gas is returned to the 5 / 10-8 / 10 section of the material surface between the ignition point of the sintering machine and the end point of sintering for oxygen-enriched steam blowing sintering, and the remaining 55% of the oxygen-enriched hot exhaust gas is returned to the 1 / 10 to 3 / 10 section of the material surface between the ignition point of the sintering machine and the end point of sintering for oxygen-enriched hot air sintering. Compared with conventional processes, the total amount of medium and low temperature waste heat waste gas is reduced by 40%, and after quality improvement, it is used in the form of waste heat power generation. At the same time, the hot air temperature of the material surface in the front stage of sintering is increased from about 100°C to 133-141°C, the overall utilization rate of sintering ring cooling waste gas waste heat is increased by 30%, the sintering ore return rate is reduced by 1.3%, the sintering ore drum strength is increased by 2.0%, and the sintering utilization coefficient is increased by 0.037t / m 2 ·h -1 , solid fuel consumption decreased by 1.55kg / t, and CO concentration in sintering flue gas decreased by 1305ppm.

[0089] Comparative Example 1

[0090] Conventional processes are used for cooling sintered ore. The exhaust gas from the low-temperature cooling section of the ring cooler (about 142°C) is directly discharged, and the exhaust gas from the medium-temperature cooling section of the ring cooler (about 219°C) is exchanged with waste heat boilers and industrial water to generate low-parameter steam with a flow rate of about 11.5 t / h, a pressure of about 0.4 MPa, and a temperature of about 180°C, and hot water with a flow rate of about 50 t / h and a temperature of about 90°C. This low-pressure steam cannot be fully utilized in the plant, and its thermal utilization efficiency is low.

[0091] Comparative Example 2

[0092] Conventional processes are used to cool sintered ore. The exhaust gas (about 142°C) from the low-temperature cooling section of the ring cooler is directly discharged, and the exhaust gas (about 219°C) from the medium-temperature cooling section of the ring cooler is returned to the sintering ignition section and the sintering material surface. Due to the high exhaust gas temperature, obvious volume expansion, and thin oxygen content (about 188 mg / L), the amount of oxygen absorbed into the sintering material layer per unit time is low, and the quality of the sintered ore is reduced. In order to ensure the sintering quality, a large amount of cold air must be added to reduce the exhaust gas temperature, resulting in the inability to fully utilize the cooling exhaust gas and its heat.

Claims

1. A system for improving the quality of low-temperature waste gas by ring cooling, characterized in that: The system comprises a shell and an inner cavity; the bottom of the shell is provided with an exhaust gas inlet (1) connected to the inner cavity; the inner cavity is divided from bottom to top into a heat supplement and oxygen supplement zone (2), a primary heat exchange zone (3), a secondary heat exchange zone (4) and a diversion and steam supplement zone (5) which are connected in series in sequence; the medium and low temperature exhaust gases of the ring cooling sequentially pass through the heat supplement and oxygen supplement zone (2), the primary heat exchange zone (3), the secondary heat exchange zone (4) and the diversion and steam supplement zone (5) and are converted into oxygen-rich hot exhaust gas and oxygen-rich steam-rich hot exhaust gas which can be directly used in the sintering process.

2. The system according to claim 1, characterized in that: The system also includes a sintering machine (6) and a ring cooler (7); according to the direction of the sintering material: a front section smoke hood (601) and a rear section smoke hood (602) are sequentially provided on the sintering machine (6); a first section wind hood (701), a second section wind hood (702) and a third section wind hood (703) are sequentially provided on the ring cooler (7); the air outlets of the second section wind hood (702) and the third section wind hood (703) are both connected to the waste gas inlet (1) through an air inlet pipe; the oxygen-rich hot waste gas outlet of the split steam supply area (5) is connected to the air inlet of the front section smoke hood (601) through a first circulating air delivery pipe (503), and the oxygen-rich steam-rich hot waste gas outlet of the split steam supply area (5) is connected to the air inlet of the rear section smoke hood (602) through a second circulating air delivery pipe (504); preferably, an electric gate valve (101) is provided in the waste gas inlet (1).

3. The system according to claim 2, characterized in that: On the sintering machine: the area covered by the front-stage smoke hood (601) is the 1 / 10 to 4 / 10 section of the material surface between the sintering ignition point and the sintering end point; the area covered by the rear-stage smoke hood (602) is the 5 / 10 to 8 / 10 section of the material surface between the sintering ignition point and the sintering end point; and / or On the ring cooler: the air outlet of the three-stage air hood (703) is first connected to the bottom air inlet of the second stage of the ring cooler located below the second-stage air hood (702) through the air supply pipe, and the air outlet of the second-stage air hood (702) is then connected to the exhaust gas inlet (1) through the air inlet pipe.

4. The system according to any one of claims 1 to 3, characterized in that: An oxygen-enriched burner (201) is provided in the heat and oxygen supply zone (2), and a combustible gas pipeline (202) and an oxygen-enriched gas pipeline (203) are connected to the oxygen-enriched burner (201); Preferably, a plurality of oxygen-enriched burners (201) are provided in the heat and oxygen supply zone (2), and each oxygen-enriched burner (201) is independently connected to a combustible gas pipeline (202) and an oxygen-enriched gas pipeline (203).

5. The system according to any one of claims 1 to 4, characterized in that: A high-parameter steam superheater (301), a high-parameter steam evaporator (302), a high-parameter economizer (303), a deaerator (304) and a low-parameter economizer (305) are arranged in order from bottom to top in the primary heat exchange zone (3); a steam drum (306), a deaerator (307), a desalted water pipe network (308) and a steam power generation device (310) are arranged outside the primary heat exchange zone (3); the front end of the high-parameter steam superheater (301) is connected to the steam power generation device (310) through a pipeline and a valve, and the rear end thereof is connected to the steam drum (310) through a pipeline. 306); the front end and the rear end of the high-parameter steam evaporator (302) are connected to the drum (306) through pipelines; the front end of the high-parameter economizer (303) is connected to the deaerator (307) through a pipeline, and the rear end thereof is connected to the drum (306) through a pipeline; the front end and the rear end of the deaerator evaporator (304) are connected to the deaerator (307) through pipelines; the front end of the low-parameter economizer (305) is connected to the desalted water network (308) through a pipeline valve (309), and the rear end thereof is connected to the deaerator (307) through a pipeline.

6. The system according to any one of claims 1 to 5, characterized in that: An industrial water heater (401) is arranged in the secondary heat exchange area (4), and an industrial water pipe network (402) and a hot water utilization pipe (403) are arranged outside the secondary heat exchange area (4); the front end of the industrial water heater (401) is connected to the industrial water pipe network (402), and the rear end thereof is connected to the hot water utilization pipe (403).

7. The system according to any one of claims 1 to 6, characterized in that: A water mist nozzle (501) and a diverter baffle (502) are arranged in the diverter steam supply area (5); the top end of the diverter baffle (502) is connected to the shell and divides the diverter steam supply area (5) into two diverter chambers arranged in parallel in the horizontal direction, the water mist nozzle (501) is arranged in one of the diverter chambers, and an oxygen-rich steam-rich hot exhaust gas outlet is opened at the top of the diverter chamber, and an oxygen-rich hot exhaust gas outlet is opened at the top of the other diverter chamber; preferably, the top end of the diverter baffle (502) is hinged to the shell, so that the diverter baffle (502) can swing in the horizontal direction to adjust the size of the two diverter chambers.

8. A method for upgrading and utilizing the medium and low temperature waste gas of annular cooling or a method for upgrading and utilizing the medium and low temperature waste gas of annular cooling using the system as claimed in any one of claims 1 to 7, characterized in that: The method includes: 1) Mix the ring-cooled medium-temperature exhaust gas and the ring-cooled low-temperature exhaust gas and perform supplementary heat and oxygen combustion to obtain oxygen-rich high-temperature hot flue gas; 2) Use hot water to perform high-temperature heat exchange on the oxygen-rich high-temperature reheated flue gas to obtain high-parameter steam and oxygen-rich medium-temperature hot flue gas; 3) Use cold water to perform low-temperature heat exchange on the oxygen-rich medium-temperature flue gas to obtain industrial hot water and oxygen-rich hot exhaust gas; 4) Using water mist to atomize, control temperature and add steam to part of the oxygen-rich hot exhaust gas to obtain oxygen-rich and steam-rich hot exhaust gas; 5) sending the oxygen-rich hot waste gas and the oxygen-rich steam-rich hot waste gas to the sintering front section and sintering back section of the sintering machine for sintering treatment respectively; Preferably, the ring-cooled low-temperature exhaust gas is first circulated as the cooling medium of the middle section of the ring-cooling, and the material is cooled and heat-exchanged to obtain the ring-cooled medium-temperature exhaust gas, and then the ring-cooled medium-temperature exhaust gas is supplemented with heat and oxygen to obtain oxygen-rich high-temperature hot flue gas.

9. The method according to claim 8, characterized in that: In step 1), the temperature of the annularly cooled low-temperature exhaust gas is lower than 150°C, preferably 110-150°C, and more preferably 120-145°C; the temperature of the annularly cooled medium-temperature exhaust gas is not lower than 150°C, preferably 160-250°C, and more preferably 170-240°C; the temperature of the oxygen-enriched high-temperature hot flue gas is not lower than 400°C, preferably 450-600°C, and more preferably 500-550°C; the oxygen concentration of the oxygen-enriched high-temperature hot flue gas is not lower than 140 mg / L, preferably 160-300 mg / L, and more preferably 180-260 mg / L; and / or In step 2), the pressure of the high-parameter steam is not less than 1.5 MPa, preferably 1.8-3 MPa, more preferably 2-2.5 MPa; the temperature of the high-parameter steam is not less than 350°C, preferably 380-500°C, more preferably 400-480°C; the temperature of the oxygen-enriched warm flue gas is not higher than 200°C, preferably 160-190°C, more preferably 170-180°C; and / or In step 3), the temperature of the oxygen-enriched hot exhaust gas is not higher than 160°C, preferably 130-155°C, and more preferably 135-150°C; the oxygen concentration of the oxygen-enriched hot exhaust gas is not lower than 310 mg / L, preferably 320-400 mg / L, and more preferably 330-380 mg / L.

10. The method according to claim 8 or 9, characterized in that: In step 4), the temperature of the oxygen-rich steam-rich hot exhaust gas is not higher than 150°C, preferably 120-145°C, more preferably 130-140°C; the oxygen concentration of the oxygen-rich steam-rich hot exhaust gas is not less than 320 mg / L, preferably 330-420 mg / L, more preferably 340-400 mg / L; the water vapor concentration of the oxygen-rich steam-rich hot exhaust gas is not less than 3wt%, preferably 3.2-5wt%, more preferably 3.5-4.5wt%; Preferably, in step 4), the oxygen-rich hot waste gas subjected to atomization, temperature control and steam addition treatment accounts for 30-55% of the total oxygen-rich hot waste gas, preferably 34-50%, more preferably 38-48%; and / or In step 4), the front section of sintering refers to the section between the 1 / 10 and 4 / 10 sections of the material surface between the sintering ignition point and the sintering end point; the back section of sintering refers to the section between the 5 / 10 and 8 / 10 sections of the material surface between the sintering ignition point and the sintering end point.

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