Low carbon sintering method based on high temperature hot air

Abstract

The present invention discloses a low-carbon sintering method based on high-temperature hot air, comprising the following steps: 1. dividing a ring cooler (7) from a feeding end to a discharging end into a high-temperature section, a medium-high-temperature section, a medium-low-temperature section and a low-temperature section in sequence; 2. arranging a hot air furnace (4) between the ring cooler and the high-temperature hot air hood (3), extracting the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section, mixing the high-temperature hot air and the medium-high-temperature hot air into circulating hot air and conveying them to the hot air furnace; 3. heating the circulating hot air in the hot air furnace by biomass fuel to form high-temperature circulating hot air; 4. conveying the high-temperature circulating hot air to the high-temperature hot air hood, so that the high-temperature circulating hot air enters the sintering machine material layer to carry out high-temperature hot air sintering of the sintering mixture. The present invention can carry out high-temperature hot air sintering on the sintering machine material surface by high-temperature circulating hot air, thereby reducing the consumption of fossil solid fuels in the sintering mixture and reducing the emission of carbon dioxide.

Description

Technical Field

[0001] The invention relates to a sintering process in the metallurgical industry, in particular to a low-carbon sintering method based on high-temperature hot air. Background Art

[0002] China's molten iron production accounts for more than 60% of the world's total production. At present, China's ironmaking process is traditional sintering + blast furnace ironmaking, and sintered ore accounts for about 70% of the total iron-containing raw materials entering the furnace, and the total annual sintered ore production reaches about 1 billion tons. The sintering process has high energy consumption, accounting for about 12% of the total energy consumption of steel production, of which about 80% is the consumption of fossil fuels such as coal coke that provide heat during the sintering process.

[0003] Chinese invention patent application CN201910933417.6 discloses a hot air sintering system and method, and specifically discloses: a hot air hood I is provided above the material surface in the front section of sintering, and a hot air hood II is provided above the material surface in the middle section of sintering, the hot air hood I is connected to the cooling exhaust gas pipeline through a branch pipe, the hot air hood II is connected to a plurality of gas mixing devices, and a throttle valve is provided on the wind box branch pipe corresponding to the rear section of sintering.

[0004] Chinese invention patent ZL201210397375.7 discloses a device and method for hot air sintering by recycling sintering high-temperature flue gas. The method uses a flue baffle to separate the sintering flue at the rear to form a front flue and a rear flue; after the high-temperature flue gas in the rear flue is purified and pressurized by a dust collector and a circulating fan, a part of the high-temperature flue gas is transported to the hot air sintering hood and the hot air insulation hood through a collecting pipe to provide hot air for the sintering process, and the other part of the high-temperature flue gas is transported to the sintering igniter after secondary pressurization by a high-pressure blower to provide hot air for the sintering igniter gas combustion.

[0005] Chinese invention patent application CN201811331593.4 discloses an iron ore sintering device and method in which biochar replaces coke based on fuel stratification and flue gas circulation. The method extracts the sintering flue gas with high temperature and low sulfur characteristics from the rear section of the sintering machine, mixes it with the cooling waste gas and then uses it for circulating sintering, and partially replaces coke with biochar, thereby reducing the consumption of fossil fuels and the production cost of iron ore sintering.

[0006] Although the above sintering device and method can reduce the fossil fuel consumption of sintering to a certain extent, there are the following problems:

[0007] 1. The temperature of circulating sintering flue gas or ring-cooling flue gas is below 350°C, which reduces the consumption of sintering fossil fuels by a very limited amount, about 1-5kg / ts, that is, the consumption of fossil fuels per ton of sintered ore is reduced by 2-10%.

[0008] 2. Due to the low energy density and fast burning speed of raw biomass, the direct use of raw biomass fuel will cause the maximum temperature of the sintering material layer to drop significantly, thus significantly reducing the output and quality of sintered ore. Therefore, the raw biomass fuel needs to be carbonized before use. The process of carbonizing biomass fuel to form biochar will increase a lot of energy consumption. In addition, since biochar burns faster than coke powder, but the calorific value of biochar is lower than that of coke powder, there are large differences in the combustion characteristics of the two. The replacement ratio of biochar to coke powder is very limited, otherwise it will reduce the quality indicators of sintered ore.

[0009] 3. In order to maintain a high circulating flue gas temperature, most of the high-temperature sintering flue gas needs to be extracted for circulation, which will reduce the flue gas temperature of the sintering main flue, thereby reducing the service life of the main flue electrostatic precipitator system, and cannot ensure the efficient and low-consumption operation of the desulfurization and denitrification system, resulting in emission pollution risks. Summary of the invention

[0010] The purpose of the present invention is to provide a low-carbon sintering method based on high-temperature hot air, which can perform high-temperature hot air sintering on the material surface of a sintering machine through high-temperature circulating hot air, thereby reducing the consumption of fossil solid fuels in the sintering mixture and reducing carbon dioxide emissions.

[0011] The present invention is achieved in that:

[0012] A low-carbon sintering method based on high-temperature hot air, the low-carbon sintering method based on high-temperature hot air is applied to a sintering machine, the sintering machine comprises: a sintering trolley, an ignition furnace arranged on the sintering trolley, a high-temperature hot air hood covering the top of the sintering trolley, and a ring cooler for cooling the hot sintered ore;

[0013] The low-carbon sintering method based on high-temperature hot air comprises the following steps:

[0014] Step 1: Divide the ring cooler into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section from the feed end to the discharge end;

[0015] Step 2: a hot air furnace is set between the ring cooler and the high-temperature hot air hood, high-temperature hot air in the high-temperature section and medium-high-temperature hot air in the medium-high-temperature section are extracted, the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the hot air furnace;

[0016] Step 3: The circulating hot air is heated by biomass fuel in the hot air furnace to form high-temperature circulating hot air;

[0017] Step 4: convey the high-temperature circulating hot air into the high-temperature hot air hood, so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixture.

[0018] In the step 2, a dust collector is arranged between the hot air furnace and the ring cooler, and the circulating hot air is dusted by the dust collector.

[0019] The dust content in the circulating hot air after dust removal is ≤45mg / m 3 .

[0020] In step 2, the temperature range of the high-temperature hot air is 400-500°C. The high-temperature hot air is: the air at ambient temperature is heat exchanged with the sintered ore in the medium and low temperature sections, and then enters the high temperature section to exchange heat with the sintered ore for the second time to generate hot air.

[0021] In the step 2, the temperature range of the medium-high temperature hot air is 280-400°C, and the medium-high temperature hot air is: the air at ambient temperature is heat exchanged with the sintered ore in the low temperature section once, and then enters the medium-high temperature section to exchange heat with the sintered ore for the second time to generate hot air.

[0022] In the step 3, the biomass fuel is raw biomass fuel, biochar or a mixture of raw biomass fuel and biochar; the particle size of the biomass fuel is less than 10 mm, and the calorific value of the biomass fuel is ≥15 MJ / kg.

[0023] In step 4, during high-temperature hot air sintering, the temperature of the high-temperature circulating hot air is inversely proportional to the proportion of the fossil solid fuel in the sintering mixture.

[0024] When the temperature of the high-temperature circulating hot air is 500-1000°C, the proportion of fossil solid fuel in the sintering mixture is 2.7-1.7%.

[0025] The fossil solid fuel in the sintering mixture is at least one of coke powder, coal powder and blue coke.

[0026] In the step 4, the high-temperature hot air hood is arranged in close contact with the outlet end of the ignition furnace, and the length of the high-temperature hot air hood accounts for 60-75% of the total length of the sintering machine.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention uses biomass fuel to heat the high-temperature hot air and the medium-high-temperature hot air after air heat exchange to form a high-temperature circulating hot air of 500-1000°C, which is used for high-temperature hot air sintering on the material surface of the sintering machine, which can significantly reduce the consumption of sintering fossil fuels and CO 2 Emissions, achieving green and low-carbon sintering.

[0029] 2. The present invention adopts an indirect heat exchange hot air furnace, which can use the original biomass fuel to heat the circulating hot air. There is no need to carbonize the biomass fuel, thereby reducing energy consumption. At the same time, it can avoid the problems of decreased sintered ore yield and quality due to the high combustion rate of biomass charcoal when directly using biomass charcoal for sintering, and increased alkali metal content in sintered ore due to the high alkali metal content in biomass charcoal.

[0030] 3. The present invention divides the ring cooler into a high-temperature section, a medium-high-temperature section, a medium-low-temperature section and a low-temperature section from the feed end to the discharge end, and adopts blower blowing control for cascade cooling, which can not only ensure the cooling effect of the sintered ore, but also further increase the temperature of the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section, thereby reducing the fuel consumption of heating the circulating hot air.

[0031] 4. Since the present invention adopts high-temperature hot air and medium-high temperature hot air to mix into circulating hot air, there is no need to extract high-temperature sintering flue gas for circulation, which can ensure the flue gas temperature in the sintering main flue, effectively avoid the reduction of flue gas temperature in the sintering main flue and cause the service life of the main flue electrostatic precipitator system to decrease, and can also ensure the efficient and low-consumption operation of the desulfurization and denitrification system.

[0032] The present invention can use raw biomass fuel to heat the circulating hot air formed by air heat exchange to 500-1000°C, and perform high-temperature hot air sintering on the sintering machine material surface through the high-temperature circulating hot air, thereby reducing the proportion of fossil solid fuel in the sintering mixture to 2.7-1.7%, ensuring the output and quality of sintered ore, while reducing carbon dioxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of the low-carbon sintering method based on high-temperature hot air of the present invention;

[0034] Figure 2 It is a schematic diagram of the application of the low-carbon sintering method based on high-temperature hot air of the present invention.

[0035] In the figure, 1 is an ignition furnace, 2 is a sintering trolley, 3 is a high-temperature hot air hood, 4 is a hot air furnace, 5 is an annular cooling circulation fan, 6 is a dust collector, 7 is an annular cooler, 8 is a low-temperature section blower, 9 is a medium-low temperature section blower, 10 is a medium-high temperature section blower, and 11 is a high-temperature section blower. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] Please see attached Figure 2 A low-carbon sintering method based on high-temperature hot air is applied to a sintering machine, which includes a sintering trolley 2, an ignition furnace 1 arranged on the sintering trolley 2, a high-temperature hot air hood 3 covering the sintering trolley 2, and a ring cooler 7 for cooling the hot sintered ore. The sintering machine can adopt traditional iron ore sintering equipment, and its specific structure and process flow are not described here.

[0038] Please see attached Figure 1 The low-carbon sintering method based on high-temperature hot air comprises the following steps:

[0039] Step 1: Divide the ring cooler 7 from the feed end to the discharge end into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section.

[0040] Step 2: A hot blast furnace 4 is arranged between the ring cooler 7 and the hot blast hood 5, and the high-temperature hot blast in the high-temperature section and the medium-high-temperature hot blast in the medium-high-temperature section are extracted, and the high-temperature hot blast and the medium-high-temperature hot blast are mixed into circulating hot blast and transported to the hot blast furnace 4 through the ring cooler circulating blower 5. Preferably, the hot blast furnace 4 can be an indirect heat exchange hot blast furnace, which is used for indirect heat exchange heating of circulating hot blast, so that the circulating hot blast can be heated by the original biomass fuel that has not been carbonized, and at the same time, it can also avoid the problems of the decrease in the yield and quality of the sintered ore due to the high combustion rate of the biomass charcoal and the increase in the alkali metal content of the sintered ore caused by the high alkali metal content of the biomass charcoal when the biomass charcoal is directly used for sintering.

[0041] A dust collector 6 is provided between the hot air furnace 4 and the ring cooler 7, and the circulating hot air is dusted by the dust collector 6. Preferably, the dust content in the circulating hot air after dust removal is ≤45mg / m 3 , ensuring the heat transfer efficiency of the circulating hot air in the hot blast stove 4, which is beneficial to extending the service life of the hot blast stove 4.

[0042] The temperature range of the high-temperature hot air is 400-500°C, and the high-temperature hot air is: the air at ambient temperature is heat exchanged with the sintered ore once in the medium-low temperature section, and then enters the high-temperature section to exchange heat with the sintered ore for the second time, which is generated by hot air. Preferably, the medium-low temperature section blower 9 can be connected to the medium-low temperature section, and the air at ambient temperature is blown into the medium-low temperature section through the medium-low temperature section blower 9 to exchange heat with the sintered ore once. Similarly, the high-temperature section blower 11 can be connected to the high-temperature section, and the air after the first heat exchange is blown into the high-temperature section through the high-temperature section blower 11 to exchange heat with the sintered ore for the second time.

[0043] The temperature range of the medium and high temperature hot air is 280-400°C, and the medium and high temperature hot air is: the air at ambient temperature is heat exchanged with the sintered ore once in the low temperature section, and then enters the medium and high temperature section to have a secondary heat exchange with the sintered ore to generate hot air. Preferably, a low temperature section blower 8 can be connected to the low temperature section, and the air at ambient temperature is blown into the low temperature section through the low temperature section blower 8 to have a primary heat exchange with the sintered ore. Similarly, a medium and high temperature section blower 10 can be connected to the medium and high temperature section, and the air after the primary heat exchange is blown into the medium and high temperature section through the medium and high temperature section blower 10 to have a secondary heat exchange with the sintered ore.

[0044] Blowers are used to carry out cascade cooling between the high temperature section, medium-high temperature section, medium-low temperature section and low temperature section to ensure the cooling effect of the sintered ore, and ensure that the high temperature hot air in the high temperature section reaches 400-500℃, and the medium-high temperature hot air in the medium-high temperature section reaches 280-400℃, reducing the heating energy consumption of the circulating hot air.

[0045] Step 3: The circulating hot air is heated by the biomass fuel in the hot air furnace 4 to form high-temperature circulating hot air. Heating the circulating hot air by the biomass fuel will not change the composition of the circulating hot air.

[0046] The particle size of the biomass fuel is less than 10 mm, and the calorific value of the biomass fuel is ≥15 MJ / kg.

[0047] The biomass fuel is raw biomass fuel, biomass charcoal or a mixture of raw biomass fuel and biomass charcoal, and the raw biomass fuel can be directly used to heat the circulating hot air. The biomass fuel can be agricultural and forestry waste, sunflower seed shells, olive residue, almond shells, wood charcoal, straw charcoal, molded sawdust, etc.

[0048] Step 4: The high-temperature circulating hot air is transported to the high-temperature hot air hood 3, and the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixture. The sintering of the sintered mixture adopts a traditional sintering process, and after sintering, the finished sintered ore is obtained by cooling, granulation, and screening, which will not be repeated here.

[0049] During the high-temperature hot air sintering, the temperature of the high-temperature circulating hot air is inversely proportional to the proportion of fossil solid fuel in the sintering mixture, that is, the higher the temperature of the high-temperature circulating hot air, the smaller the proportion of fossil solid fuel in the sintering mixture, and conversely, the lower the temperature of the high-temperature circulating hot air, the greater the proportion of fossil solid fuel in the sintering mixture.

[0050] When the temperature of the high-temperature circulating hot air is 500-1000°C, the proportion of fossil solid fuel in the sintering mixture is 2.7-1.7%. Compared with the prior art, the consumption of fossil solid fuel in the sintering mixture can be reduced by 26-55%.

[0051] The fossil solid fuel in the sintering mixture is at least one of coke powder, coal powder and blue charcoal, and biomass charcoal is not used to replace coke powder, thereby ensuring the output and quality of sintered ore.

[0052] The high-temperature hot air hood 3 is arranged in close contact with the outlet end of the ignition furnace 1, and the length of the high-temperature hot air hood 3 accounts for 60-75% of the total length of the sintering machine, so that the sintering mixture enters the bottom of the high-temperature hot air hood 3 for high-temperature hot air sintering after being output from the ignition furnace 1, which can significantly reduce the consumption of sintering fossil fuels and CO 2 Emissions, achieving green and low-carbon sintering.

[0053] Embodiment 1:

[0054] Step 1: Divide the ring cooler 7 from the feed end to the discharge end into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section.

[0055] Step 2: A hot air furnace 4 is set between the ring cooler 7 and the hot air hood 5, and the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section are extracted, and the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the indirect heat exchange hot air furnace 4 after dust removal by the dust collector 6.

[0056] The dust content in the circulating hot air after dust removal is ≤30mg / m 3 .

[0057] The temperature range of high-temperature hot air is 400°C. High-temperature hot air is: air at ambient temperature is blown into the medium-low temperature section by the medium-low temperature section blower 9 to exchange heat with the sintered ore once, and then blown into the high-temperature section by the high-temperature section blower 11 to exchange heat with the sintered ore twice to generate hot air.

[0058] The temperature range of medium and high temperature hot air is 280°C. The medium and high temperature hot air is: air at ambient temperature is blown into the low temperature section through the low temperature section blower 8 to perform a heat exchange with the sintered ore, and then blown into the medium and high temperature section through the medium and high temperature section blower 10 to perform a secondary heat exchange with the sintered ore.

[0059] Step 3: The circulating hot air is heated in the hot air furnace 4 by the original biomass fuel with a particle size less than 10 mm and a calorific value ≥ 15 MJ / kg to form a high-temperature circulating hot air of 500°C.

[0060] Step 4: transport the high-temperature circulating hot air to the high-temperature hot air hood 3, so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixed material. The high-temperature hot air hood 3 is arranged in close contact with the outlet end of the ignition furnace 1, and the length of the high-temperature hot air hood 3 accounts for 75% of the total length of the sintering machine.

[0061] The proportion of fossil solid fuel in the sintering mixture is 2.7%. By mass percentage, the fossil solid fuel in the sintering mixture is a mixture of 80% coke powder and 20% coal powder.

[0062] The sintering of the sintered mixture adopts the traditional sintering process, and the finished sintered ore is obtained by cooling, granulation and screening after sintering, which will not be repeated here. The finished product rate of the sintered ore obtained in this embodiment is 80.26%, which is 0.33% higher than that of the prior art, and the unit consumption of fossil solid fuel is 36.74kg / ts, which is 26.52% lower than that of the prior art.

[0063] Embodiment 2:

[0064] Step 1: Divide the ring cooler 7 from the feed end to the discharge end into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section.

[0065] Step 2: A hot air furnace 4 is set between the ring cooler 7 and the hot air hood 5, and the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section are extracted, and the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the indirect heat exchange hot air furnace 4 after dust removal by the dust collector 6.

[0066] The dust content in the circulating hot air after dust removal is ≤40mg / m 3 .

[0067] The temperature range of high-temperature hot air is 420°C. High-temperature hot air is: air at ambient temperature is blown into the medium-low temperature section by the medium-low temperature section blower 9 to exchange heat with the sintered ore once, and then blown into the high-temperature section by the high-temperature section blower 11 to exchange heat with the sintered ore twice to generate hot air.

[0068] The temperature range of medium and high temperature hot air is 300°C. The medium and high temperature hot air is: air at ambient temperature is blown into the low temperature section through the low temperature section blower 8 to perform a heat exchange with the sintered ore, and then blown into the medium and high temperature section through the medium and high temperature section blower 10 to perform a secondary heat exchange with the sintered ore.

[0069] Step 3: The circulating hot air is heated in the hot air furnace 4 by the original biomass fuel with a particle size less than 10 mm and a calorific value ≥ 18 MJ / kg to form a high-temperature circulating hot air of 600°C.

[0070] Step 4: transport the high-temperature circulating hot air to the high-temperature hot air hood 3, so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixed material. The high-temperature hot air hood 3 is arranged in close contact with the outlet end of the ignition furnace 1, and the length of the high-temperature hot air hood 3 accounts for 70% of the total length of the sintering machine.

[0071] The proportion of fossil solid fuel in the sintering mixture is 2.4%, and the fossil solid fuel in the sintering mixture is coke powder.

[0072] The sintering of the sintered mixture adopts the traditional sintering process, and the finished sintered ore is obtained by cooling, granulation and screening after sintering, which will not be repeated here. The finished product rate of the sintered ore obtained in this embodiment is 80.35%, which is 0.44% higher than that of the prior art, and the unit consumption of fossil solid fuel is 32.55kg / ts, which is 34.90% lower than that of the prior art.

[0073] Embodiment 3:

[0074] Step 1: Divide the ring cooler 7 from the feed end to the discharge end into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section.

[0075] Step 2: A hot air furnace 4 is set between the ring cooler 7 and the hot air hood 5, and the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section are extracted, and the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the indirect heat exchange hot air furnace 4 after dust removal by the dust collector 6.

[0076] The dust content in the circulating hot air after dust removal is ≤45mg / m 3 .

[0077] The temperature range of high-temperature hot air is 450°C. High-temperature hot air is: air at ambient temperature is blown into the medium-low temperature section by the medium-low temperature section blower 9 to exchange heat with the sintered ore once, and then blown into the high-temperature section by the high-temperature section blower 11 to exchange heat with the sintered ore twice to generate hot air.

[0078] The temperature range of medium and high temperature hot air is 350°C. The medium and high temperature hot air is: air at ambient temperature is blown into the low temperature section through the low temperature section blower 8 to perform a heat exchange with the sintered ore, and then blown into the medium and high temperature section through the medium and high temperature section blower 10 to perform a secondary heat exchange with the sintered ore.

[0079] Step 3: The circulating hot air is heated in the hot air furnace 4 by the original biomass fuel with a particle size less than 10 mm and a calorific value ≥ 20 MJ / kg to form a high-temperature circulating hot air of 800°C.

[0080] Step 4: transport the high-temperature circulating hot air to the high-temperature hot air hood 3, so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixed material. The high-temperature hot air hood 3 is arranged in close contact with the outlet end of the ignition furnace 1, and the length of the high-temperature hot air hood 3 accounts for 65% of the total length of the sintering machine.

[0081] The proportion of fossil solid fuel in the sintering mixture is 2.0%. By mass percentage, the fossil solid fuel in the sintering mixture is a mixture of 80% coke powder and 20% lignite.

[0082] The sintering of the sintered mixture adopts the traditional sintering process, and the finished sintered ore is obtained by cooling, granulation and screening after sintering, which will not be repeated here. The finished product rate of the sintered ore obtained in this embodiment is 79.96%, which is basically consistent with the prior art, and the unit consumption of fossil solid fuel is 27.01kg / ts, which reduces the unit consumption of fossil solid fuel by 45.98% compared with the prior art.

[0083] Embodiment 4:

[0084] Step 1: Divide the ring cooler 7 from the feed end to the discharge end into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section.

[0085] Step 2: A hot air furnace 4 is set between the ring cooler 7 and the hot air hood 5, and the high-temperature hot air in the high-temperature section and the medium-high-temperature hot air in the medium-high-temperature section are extracted, and the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the indirect heat exchange hot air furnace 4 after dust removal by the dust collector 6.

[0086] The dust content in the circulating hot air after dust removal is ≤45mg / m 3 .

[0087] The temperature range of high-temperature hot air is 500°C. High-temperature hot air is: air at ambient temperature is blown into the medium-low temperature section by the medium-low temperature section blower 9 to exchange heat with the sintered ore once, and then blown into the high-temperature section by the high-temperature section blower 11 to exchange heat with the sintered ore twice to generate hot air.

[0088] The temperature range of medium and high temperature hot air is 400°C. The medium and high temperature hot air is: air at ambient temperature is blown into the low temperature section through the low temperature section blower 8 to perform a heat exchange with the sintered ore, and then blown into the medium and high temperature section through the medium and high temperature section blower 10 to perform a secondary heat exchange with the sintered ore.

[0089] Step 3: The circulating hot air is heated in the hot air furnace 4 by the original biomass fuel with a particle size less than 10 mm and a calorific value ≥ 25 MJ / kg to form a high-temperature circulating hot air of 1000°C.

[0090] Step 4: transport the high-temperature circulating hot air to the high-temperature hot air hood 3, so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixed material. The high-temperature hot air hood 3 is arranged in close contact with the outlet end of the ignition furnace 1, and the length of the high-temperature hot air hood 3 accounts for 60% of the total length of the sintering machine.

[0091] The proportion of fossil solid fuel in the sintering mixture is 1.7%. By mass percentage, the fossil solid fuel in the sintering mixture is a mixture of 70% coal powder and 30% lignite.

[0092] The sintering of the sintered mixture adopts the traditional sintering process, and the finished sintered ore is obtained by cooling, granulation and screening after sintering, which will not be repeated here. The finished product rate of the sintered ore obtained in this embodiment is 79.63%, which is basically consistent with the prior art, and the unit consumption of fossil solid fuel is 22.48kg / ts, which reduces the unit consumption of fossil solid fuel by 55.04% compared with the prior art.

[0093] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, 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. A low-carbon sintering method based on high-temperature hot air, the low-carbon sintering method based on high-temperature hot air is applied to a sintering machine, the sintering machine comprises: A sintering trolley (2), an ignition furnace (1) arranged on the sintering trolley (2), a high-temperature hot air hood (3) covering the top of the sintering trolley (2), and a ring cooler (7) for cooling the hot sintered ore; The characteristic is that the low-carbon sintering method based on high-temperature hot air comprises the following steps: Step 1: dividing the ring cooler (7) into a high temperature section, a medium-high temperature section, a medium-low temperature section and a low temperature section from the feed end to the discharge end; Step 2: a hot air furnace (4) is arranged between the ring cooler (7) and the high-temperature hot air hood (3), high-temperature hot air in the high-temperature section and medium-high-temperature hot air in the medium-high-temperature section are extracted, the high-temperature hot air and the medium-high-temperature hot air are mixed into circulating hot air and transported to the hot air furnace (4); The temperature range of the high-temperature hot air is 400-500°C. The high-temperature hot air is: the air at ambient temperature is heat-exchanged with the sintered ore in the medium and low temperature section, and then enters the high temperature section to exchange heat with the sintered ore for the second time to generate hot air; The temperature range of the medium and high temperature hot air is 280-400°C. The medium and high temperature hot air is: the air at ambient temperature is heat exchanged with the sintered ore in the low temperature section once, and then enters the medium and high temperature section to exchange heat with the sintered ore twice to generate hot air; The hot air furnace (4) is an indirect heat exchange hot air furnace; Step 3: The circulating hot air is heated by biomass fuel in the hot air furnace (4) to form high-temperature circulating hot air; Step 4: conveying the high-temperature circulating hot air into the high-temperature hot air hood (3), so that the high-temperature circulating hot air enters the sintering machine material layer to perform high-temperature hot air sintering of the sintered mixed material; When the temperature of the high-temperature circulating hot air is 500-1000°C, the proportion of fossil solid fuel in the sintering mixture is 2.7-1.7%.

2. The low-carbon sintering method based on high-temperature hot air according to claim 1 is characterized in that: In the above-mentioned step 2, a dust collector (6) is arranged between the hot air furnace (4) and the ring cooler (7), and the circulating hot air is dusted by passing through the dust collector (6).

3. The low-carbon sintering method based on high-temperature hot air according to claim 2 is characterized in that: The dust content in the circulating hot air after dust removal is ≤45mg / m 3 .

4. The low-carbon sintering method based on high-temperature hot air according to claim 1 is characterized in that: In the step 3, the biomass fuel is raw biomass fuel, biochar or a mixture of raw biomass fuel and biochar; the particle size of the biomass fuel is less than 10 mm, and the calorific value of the biomass fuel is ≥15 MJ / kg.

5. The low-carbon sintering method based on high-temperature hot air according to claim 1 is characterized in that: In step 4, during high-temperature hot air sintering, the temperature of the high-temperature circulating hot air is inversely proportional to the proportion of the fossil solid fuel in the sintering mixture.

6. The low-carbon sintering method based on high-temperature hot air according to claim 1 is characterized in that: The fossil solid fuel in the sintering mixture is at least one of coke powder, coal powder and blue coke.

7. The low-carbon sintering method based on high-temperature hot air according to claim 1 is characterized in that: In the step 4, the high-temperature hot air hood (3) is arranged in close contact with the outlet end of the ignition furnace (1), and the length of the high-temperature hot air hood (3) accounts for 60-75% of the total length of the sintering machine.

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