CN114854983B - Sintered carbon emission reduction method based on efficient fuel combustion in ultra-high material layer sintering process - Google Patents
Sintered carbon emission reduction method based on efficient fuel combustion in ultra-high material layer sintering process Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
Abstract
The invention discloses a sintered carbon emission reduction method based on efficient combustion of fuel in an ultra-high material layer sintering process, which comprises the steps of granulating fine-fraction fuel and part of iron concentrate for one time to obtain a pellet I; mixing the pellets I with raw materials comprising coarse-grain fuel, medium-grain fuel, flux, the rest part of iron ore and return ore, and performing secondary pelletization to obtain pellets II; sequentially carrying out super-thick cloth, ignition and sintering on the pellets II; and oxygen-enriched gas medium is blown to the surface of the sintering material between the end of ignition and heat preservation and the temperature rising point of the sintering waste gas temperature in the sintering process. The method can lead the thermal state of the whole sintering material layer to be uniform under the condition of ultra-thick material layer, improve the combustion efficiency of fossil fuel, reduce the consumption of fossil fuel and realize the reduction of CO emission 2 15-30%, and 20-40% CO, and the yield is improved.
Description
Technical Field
The invention relates to a sintering method, in particular to a sintered carbon emission reduction method based on efficient fuel combustion in an ultra-high material layer sintering process, and belongs to the sintering industry in the field of ferrous metallurgy.
Background
As a front-end process of the steel industry, sintering has high energy consumption and large pollution load, and brings serious challenges to clean production of the steel industry. In the traditional sintering process, solid fossil fuel such as coke, anthracite and the like is generally adopted as a heat source for the physicochemical reaction in the high-temperature process, and the heat source accounts for 75% -80% of the sintering energy consumption. Numerous studies have demonstrated that solid fossil fuel combustion is CO in sintering flue gas 2 、SO X Important sources of production and major sources of NO production. In addition, 10 to 15 percent of carbon is converted into CO due to incomplete combustion of the solid fuel, so that energy waste and environmental pollution are caused.
In recent years, in order to improve the yield based on the original sintering equipment, part of sintering factories adopt an ultra-thick material layer sintering technology, but practical application results are not as expected. The reason is that after the height of the sintering material layer is increased, the automatic heat accumulation effect of the lower part of the sintering material layer is enhanced, the temperature difference of the upper material layer and the lower material layer is increased, the upper material layer is cooled too fast, the temperature of the lower material layer is higher under the automatic heat accumulation effect, and on one hand, the corrosion of the trolley grate bar is increased under the high temperature effect; on the other hand, the liquid phase amount is increased due to the excessively high material layer and the excessively high bottom temperature, and the combustion zone is thickened, so that the air permeability of the sintered material layer is rapidly deteriorated. Therefore, in the sintering process of the ultra-thick material layer, the oxygen potential in the material layer is low, the upper and lower temperature difference is large, and the fuel combustion efficiency is low.
In the oxygen-enriched sintering process, a gas medium with the oxygen concentration higher than 21% is sprayed to the surface of the sintering material, and the oxidizing atmosphere in the material layer is improved to create an environment which is beneficial to complete combustion of fuel. Mei Gang the drum strength of the sintered ore is improved by 1.52 percent, the low-temperature reduction degradation index is improved by 0.328 percent, the reducibility is improved by 0.6 percent, and the ignition gas unit consumption is reduced by 0.166m 3 And/t, the solid burnup is reduced by 0.303kg/t.
However, the effect of pure oxygen enrichment measures on soaking low carbon in ultra-high material layer sintering is not obvious, the carbon reduction degree is limited, and the problem that too coarse and too fine coke powder is detrimental to the sintering process exists as a sintering fuel.
Disclosure of Invention
Aiming at the technical problems existing in the existing ultra-thick material layer sintering process, the invention aims to provide a sintered carbon emission reduction method based on efficient combustion of fuel in the ultra-thick material layer sintering process, and the method aims at the characteristics of different section characteristics and different section requirements on oxygen content of a sintered material in the ultra-thick material layer sintering process, and by properly selecting the type and granularity of the sintered solid fuel and adopting a special granulating process, simultaneously, the sintering is carried out by reasonably blowing oxygen-enriched gas medium, so that the limitation of different oxygen content requirements at different heights of the material layer can be met to a greater extent, the fuel combustion efficiency is synergistically improved, the consumption of solid fossil fuel is further reduced, the soaking low carbon in the sintering process is realized, and the CO is enabled 2 And pollutants such as greenhouse gases, CO and the like are effectively reduced.
In order to achieve the technical aim, the invention provides a sintered carbon emission reduction method based on efficient combustion of fuel in an ultra-high material layer sintering process, which comprises the steps of granulating fine-fraction fuel and part of iron concentrate for one time to obtain pellets I; mixing the pellets I with raw materials including the rest part of iron ore, coarse-grain fuel, medium-grain fuel, flux and return ore, and performing secondary pelletization to obtain pellets II; sequentially carrying out super-thick cloth, ignition and sintering on the pellets II; and in the sintering process, oxygen-enriched gas medium is sprayed to the surface of the sintering material between the end of ignition and heat preservation and the temperature rising point of the sintering waste gas temperature.
In general, fine-fraction fuel acts as an adhesive powder in pelletization, so fine-fraction coke powder tends to adhere to the outermost surface of the pellets during pelletization, and when the pellets are sintered, a large amount of CO is generated under the condition that the air permeability of an ultra-thick material layer is relatively poor due to the excessively high burning speed of the fine-fraction coke powder on the surface, and a part of CO is discharged along with flue gas after being incompletely oxidized, which is one of the main reasons for reducing the fuel utilization efficiency. According to the technical scheme, the fine-grain fuel and the iron ore concentrate are granulated in advance, the iron ore concentrate adhered with the fine-grain fuel is taken as nuclear particles to participate in secondary granulation, so that the fine-grain fuel is agglomerated in the granulating pellets, the reduction of combustion efficiency caused by the excessively fast combustion of the fine-grain fuel on the surfaces of the pellets is avoided, the coarse-grain fuel, the medium-grain fuel and the iron ore concentrate are uniformly distributed in the secondary granulation process, more heat can be released in the combustion process to raise the sintering highest temperature, and the integral sintering quality of the ultra-thick material layer is ensured. Meanwhile, based on the fact that the oxygen potential in the material layer is low in the ultra-thick material layer sintering process, the upper temperature difference and the lower temperature difference are large, so that the fuel combustion efficiency is low, and the fossil fuel consumption is high.
As a preferred embodiment, the coarse fraction fuel has a particle size composition of>3mm; the granularity range of the medium-granularity fuel is 0.5-3 mm; the particle size composition of the fine fraction fuel is<0.5mm. As a preferred scheme, the mass percentages of the fine-fraction fuel, the medium-fraction fuel and the coarse-fraction fuel are as follows: 15-30 percent of 50-70 percent of 15-30 percent of the water. According to the technical scheme, the fuel is classified based on the fact that fine-fraction fuel with the diameter of-0.5 mm is mainly adhered to the surfaces of granular particles, so that when the prepared granular particles are sintered, a large amount of CO is generated under the condition that the air permeability of an ultra-thick material layer is poor due to the fact that the fine-fraction combustion speed is too high, and part of CO is discharged along with smoke after being not completely oxidized, so that the fuel efficiency is reduced. And the-0.5 mm fine fraction fuel and the iron ore concentrate are pre-granulated into particles with the diameter of +0.5mm, so that the particles are used as nuclear particles to participate in subsequent granulation, the-0.5 mm fine fraction fuel is agglomerated in the granulating pellets, and the reduction of combustion efficiency caused by excessively fast combustion on the surface is avoided. And for the coke powder combustion process with the size of +3mm, more heat can be released to raise the sintering highest temperature, but at the same time, the coarse-size coke powder has poor reactivity and low combustion speed, the combustion zone is promoted to be thicker, the air permeability of the material layer is deteriorated by the excessively thick combustion zone, and the fuel combustion efficiency is reduced. According to the technical scheme, the +3mm coarse-grain grade fuel adopts the high-reactivity biomass fuel to replace coke powder, so that on one hand, during sintering, the coarse-grain grade high-reactivity solid fuel burns more rapidlyThe thickness of the burning zone is proper, the air permeability of the sintering material layer is ensured, and the fuel is promoted to burn efficiently; on the other hand, the biomass fuel is used for replacing the coke powder for sintering, so that CO in the sintering flue gas can be reduced 2 And the emission amount of the powder is low-carbon sintering.
As a preferred scheme, the medium-grade fuel comprises at least one of coke powder, anthracite and semi-coke.
As a preferred embodiment, the fine fraction fuel includes at least one of coke breeze, anthracite, and semi-coke.
As a preferred scheme, the coarse fraction fuel comprises at least one of straw charcoal, sawdust charcoal, kernel charcoal and charcoal.
As a preferable scheme, in the primary pelletization process, the mass ratio of the fine fraction fuel to the iron ore concentrate is 1:5-1:6.5, and the pelletization time is 1.5-3 min. Under the preferred granulation conditions, a particle size of +0.5mm for the pellets I can be ensured.
As a preferred embodiment, the average particle diameter of the pellets I is 1 to 3mm.
As a preferable scheme, the thickness of the layer of the super-thick cloth is not less than 950mm.
As a preferable scheme, the area of the sintering material surface from the end of ignition and heat preservation to the temperature rising point of sintering waste gas is divided into three oxygen-enriched gas medium injection areas of an area-1, an area-2 and an area-3, and the lengths of the three areas are 15% -25%, 60% -65% and 10% -25%. The area division of the sintering material surface mainly depends on the air permeability of the ultra-thick material layer and the emission characteristic of carbon oxides in the flue gas, the formation of an over-wet zone of the sintering material layer is started in an area-1, the air permeability of the sintering material layer is gradually deteriorated, the CO content in the flue gas is gradually increased, and oxygen-enriched gas medium with medium concentration in the area is blown; in the area-2, the overwet zone is completely formed and gradually moves towards the lower part of the sintering material layer, the air permeability of the sintering material layer is the worst, the concentration of CO in the flue gas is high, the emission is stable, and the area is sprayed with high-concentration oxygen-enriched gas medium; in the region-3, the overwet zone reaches the bottom of the material layer and gradually disappears, the air permeability of the material layer of the sintering material is increased near the sintering end point, the CO concentration is slightly reduced, and a low-concentration oxygen-enriched gas medium is sprayed in the region. The 'medium-high-low' variable-concentration gradient oxygen-enriched injection is formed in the whole injection interval, so that the oxygen demand of fuel combustion in different areas is accurately met, and the efficient combustion of fuel is promoted.
As a preferable scheme, the oxygen-enriched gas medium is mixed gas of oxygen and air according to the volume ratio of 1:200-1:20.
As a preferable scheme, the concentration of the oxygen-enriched gas medium sprayed in the area-1 is 22% -22.75%.
As a preferable scheme, the concentration of the oxygen-enriched gas medium sprayed in the area-2 is 23% -24%.
As a preferable scheme, the concentration of the oxygen-enriched gas medium sprayed in the area-3 is 21.5% -22%.
The invention divides the area between the end of ignition and the beginning of rising of the temperature of the waste gas into three oxygen-enriched gas medium injection areas, injects medium-concentration oxygen-enriched gas medium into the area-1, injects high-concentration oxygen-enriched gas medium into the area-2, injects low-concentration oxygen-enriched gas medium into the area-3, mainly based on the air permeability of the super-thick material layer and the discharge characteristic of carbon oxides in the flue gas, has different oxygen demand requirements in the sintering process of different sintering material layer height areas in the sintering process of the super-thick material layer, and can lead the thermal state of the whole super-thick material layer to be uniform, improve the fuel combustion efficiency and reduce the solid fossil fuel consumption by carrying out area division between the end of ignition of the sintering material layer and the beginning of rising of the temperature of the waste gas.
The end of ignition and heat preservation and the temperature rising point of sintering waste gas are common definitions in the industry.
Compared with the prior art, the technical scheme of the invention has the beneficial technical effects that:
(1) Compared with the common sintering, the ultra-thick material layer sintering can improve the productivity, but the heat difference between the upper material layer and the lower material layer is more obvious, and meanwhile, under the condition of the ultra-thick material layer, the air permeability of the whole sintering material layer is poor, and the internal oxygen potential is low, so that the full combustion of fuel is not facilitated. According to the technical scheme, oxygen-enriched sintering measures are adopted under the condition of an ultra-thick material layer, and oxygen is additionally injected into the material layer, so that the oxygen potential in the material layer is improved, the fuel combustion condition is improved, and the high-efficiency combustion of the fuel is promoted.
(2) According to the technical scheme, a blowing area of a sintering material surface is divided into three areas according to the air permeability of an ultra-thick material layer and the emission rule characteristics of carbon oxides in flue gas, the over-wet zone of the sintering material layer starts to form in an area-1, the air permeability of the sintering material layer gradually worsens, meanwhile, the CO content in the flue gas gradually increases, and oxygen with medium concentration is blown in the area; in the area-2, the overwet zone is completely formed and gradually moves towards the lower part of the material layer, the air permeability of the sintering material layer is the worst, the concentration of CO in the flue gas is high, the emission is stable, and high-concentration oxygen is blown in the area; in zone-3, the overwet zone reaches the bottom of the sinter bed and gradually disappears, approaching the end of sintering, the gas permeability of the sinter bed increases, the CO concentration slightly decreases, and low-concentration oxygen is blown in this zone. The 'medium-high-low' variable-concentration gradient oxygen-enriched injection is formed in the whole injection interval, so that the oxygen demand of fuel combustion in different areas is accurately met, and the efficient combustion of fuel is promoted.
(3) Because the-0.5 mm grade fuel plays a role of adhering powder in pelletization, the fine grade fuel is mainly adhered to the surface of the particles, and the formed pellets are sintered, so that a large amount of CO can be generated due to the fact that the combustion speed of the fine grade fuel with the surface of-0.5 mm is too high, particularly under the condition that the air permeability of an ultra-thick material layer is poor, and a part of CO is discharged along with flue gas after being incompletely oxidized, which is one of the main reasons for reducing the fuel utilization efficiency. According to the technical scheme, the fine-grained fuel with the particle size of-0.5 mm and the iron concentrate are granulated into particles with the particle size of 1-3 mm in advance, so that the particles are used as nuclear particles to participate in subsequent granulation. After the two pelletization is completed, the fine-particle grade fuel with the particle size of-0.5 mm is agglomerated in the pelletization pellets, so that the combustion efficiency is prevented from being reduced due to the excessively fast combustion on the surface.
(4) The combustion process of the +3mm coarse fraction fuel can release more heat to raise the sintering highest temperature, but the coarse fraction fuel is poor in reactivity and low in combustion speed, so that the combustion zone is thickened, the air permeability of the material layer is deteriorated, and the fuel combustion efficiency is reduced. According to the technical scheme, the high-reactivity biomass solid fuel is used for replacing the conventional fuel with the +3mm particle-size fuelIs a solid fossil fuel of (a). On the one hand, during sintering, the coarse-grain-level high-reactivity biomass fuel burns more rapidly, so that the thickness of a burning zone is proper, the air permeability of a sintering material layer is ensured, and the fuel is promoted to burn efficiently; on the other hand, the biomass fuel is used for replacing solid fossil fuel for sintering, so that CO in sintering flue gas can be reduced 2 And the emission amount of the powder is low-carbon sintering.
(5) Aiming at the characteristics of different section characteristics of sintering materials and different requirements on oxygen content in the ultra-thick material layer sintering process, the technical scheme of the invention can meet the limitation of different oxygen content requirements at different heights of the material layer to a greater extent by regulating and controlling the types and granularity characteristics of the sintering solid fuel and adopting a special granulating process and reasonably blowing oxygen-enriched gas medium for sintering, and simultaneously synergistically improves the fuel combustion efficiency, can realize the improvement of the sinter yield by 3-5%, the improvement of the drum strength by 4-6%, the reduction of the solid fuel consumption of each ton of the sinter by 2-5 kg, the reduction of the CO emission by 20-40% and the CO emission by 20-40% 2 The emission is reduced by 15-30%, and the method has important significance for green manufacturing in the iron and steel industry.
Detailed Description
The following specific examples are intended to further illustrate the present invention, but are not intended to limit the scope of the claims.
Example 1
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.68% of coke powder and 0.85% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 17%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 59%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 24%. Mixing fine-grained coke powder and part of iron ore concentrate, pre-granulating (the mixing mass ratio of the fine-grained coke powder to the part of iron ore concentrate is 1:5, the granulating time is 2min, the average particle size of the particles I is 1.68 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain particles II with a conventional size, distributing the particles II on sintering, distributing the particles II to the height of 1000mm, igniting for 1min at 1050+/-50 ℃, preserving heat for 1min, and sintering under the condition of negative pressure of 15 kPa. The total area of the sintering machine is 450m 2 A total of 24 bellows. Dividing the interval from the ignition end to the exhaust gas temperature start to rise in the sintering process into three oxygen-enriched gas medium injection areas: the area-1 accounts for 15% of the whole interval, and the concentration of oxygen injected into the oxygen-enriched medium is 22%; the area-2 accounts for 60% of the whole interval, and the oxygen concentration in the oxygen-enriched gas medium is 23%; zone-3 comprises 25% of the total zone and the oxygen concentration in the injected oxygen-enriched gaseous medium is 21.5%. The effects on the sintering index and the pollutant emission reduction effect after the method described in this example was used compared with conventional sintering (comparative example 1) are shown in tables 1 and 2, respectively.
Example 2
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.89% of coke powder and 0.64% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 20%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 62%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 18%. Mixing fine-grained coke powder and part of iron concentrate, pre-granulating (the mixing mass ratio of the fine-grained coke powder to the part of iron concentrate is 1:5.75, the granulating time is 2min, the average particle size of the particles I is 2.06 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain particles II with a conventional size, distributing the particles II on sintering, distributing the particles II to the height of 1000mm, igniting for 1min at 1050+/-50 ℃, preserving heat for 1min, and sintering under the condition of negative pressure of 15 kPa. Dividing the interval from the ignition end to the exhaust gas temperature start to rise in the sintering process into three oxygen-enriched gas medium injection areas: the area-1 accounts for 25% of the whole interval, and the concentration of oxygen injected into the oxygen-enriched medium is 22.75%; the area-2 accounts for 65% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 24%; zone-3 comprises 10% of the total interval and the oxygen concentration in the injected oxygen-enriched gaseous medium is 22%. The effects on the sintering index and the pollutant emission reduction effect after the method described in this example was used compared with conventional sintering (comparative example 1) are shown in tables 1 and 2, respectively.
Example 3
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.86% of coke powder and 0.67% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 27%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 54%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 19%. Mixing fine-grained coke powder and part of iron concentrate, pre-granulating (the mixing mass ratio of the fine-grained coke powder to the part of iron concentrate is 1:6.5, the granulating time is 2min, the average particle size of the particles I is 2.82 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain particles II with a conventional size, distributing the particles II on sintering, distributing the particles II to the height of 1000mm, igniting for 1min at 1050+/-50 ℃, preserving heat for 1min, and sintering under the condition of negative pressure of 15 kPa. Dividing the interval from the ignition end to the exhaust gas temperature start to rise in the sintering process into three oxygen-enriched gas medium injection areas: the area-1 accounts for 20% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 22.5%; the area-2 accounts for 60% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 23.5%; zone-3 comprises 20% of the total zone and the oxygen concentration in the injected oxygen-enriched gaseous medium is 21.75%. The effects on the sintering index and the pollutant emission reduction effect after the method described in this example was used compared with conventional sintering (comparative example 1) are shown in tables 1 and 2, respectively.
Comparative example 1
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore and 3.53% of coke powder (the obtained sintered mineral chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle coke powder (-0.5 mm) is 27%, the proportion of medium-particle coke powder (0.5-3 mm) is 54%, and the proportion of coarse-particle coke powder (+3 mm) is 19%. The materials are mixed and granulated to obtain granules II with the conventional size, the granules II are distributed on sintering, the distribution height is 1000mm, ignition is carried out for 1min at the temperature of 1050+/-50 ℃, the heat is preserved for 1min, and then sintering is carried out under the condition of negative pressure of 15 kPa. The sintering yield index is shown in table 1.
Comparative example 2
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.86% of coke powder and 0.67% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 27%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 54%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 19%. Mixing fine-grained coke powder and part of iron concentrate, pre-granulating (the mixing mass ratio of the fine-grained coke powder to the part of iron concentrate is 1:6.5, the granulating time is 2min, the average particle size of the particles I is 2.82 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain particles II with a conventional size, distributing the particles II on sintering, distributing the particles II to the height of 1000mm, igniting for 1min at 1050+/-50 ℃, preserving heat for 1min, and sintering under the condition of negative pressure of 15 kPa. The sintering index is shown in table 1.
Comparative example 3
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore and 3.53% of coke powder (the obtained sintered mineral chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-grained coke powder (-0.5 mm) is 27%, the proportion of medium-grained coke powder (0.5-3 mm) is 54%, and the proportion of coarse-grained coke powder (+3 mm) is 19%. Mixing fine-grained coke powder and part of iron concentrate, pre-granulating (the mixing mass ratio of the fine-grained coke powder to the part of iron concentrate is 1:6.5, the granulating time is 2min, the average particle size of the particles I is 2.82 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain particles II with a conventional size, distributing the particles II on sintering, distributing the particles II to the height of 1000mm, igniting for 1min at 1050+/-50 ℃, preserving heat for 1min, and sintering under the condition of negative pressure of 15 kPa. Dividing the interval from the ignition end to the exhaust gas temperature start to rise in the sintering process into three oxygen-enriched gas medium injection areas: the area-1 accounts for 20% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 22.5%; the area-2 accounts for 60% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 23.5%; zone-3 comprises 20% of the total zone and the oxygen concentration in the injected oxygen-enriched gaseous medium is 21.75%. The effects on the sintering index and the pollutant emission reduction effect after the method described in this comparative example are shown in tables 1 and 2, respectively.
Comparative example 4
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.86% of coke powder and 0.67% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 27%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 54%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 19%. Mixing the raw materials, granulating to obtain granules with conventional size, distributing the granules on sintering, distributing the height of 1000mm, igniting at 1050+ -50deg.C for 1min, maintaining the temperature for 1min, and sintering under negative pressure of 15 kPa. Dividing the interval from the ignition end to the exhaust gas temperature start to rise in the sintering process into three oxygen-enriched gas medium injection areas: the area-1 accounts for 25% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 22.75%; the area-2 accounts for 65% of the whole interval, and the oxygen concentration in the injected oxygen-enriched gas medium is 23.5%; zone-3 comprises 10% of the total interval and the oxygen concentration in the injected oxygen-enriched gaseous medium is 22%. The effects on the sintering index and the pollutant emission reduction effect after the method described in the embodiment are shown in-1 and table 2 respectively.
Comparative example 5
The raw materials are mixed according to the mass ratio of 60.74% of iron ore, 2.19% of dolomite, 6.58% of quicklime, 11.77% of sintered return ore, 15.19% of blast furnace return ore, 2.86% of coke powder and 0.67% of kernel carbon (the obtained sintered mineralized chemical components are TFe56.97%, R2.05, mgO1.45% and CaO 10.29%), wherein the proportion of fine-particle-grade coke powder (-0.5 mm) is 27%, the proportion of medium-particle-grade coke powder (0.5-3 mm) is 54%, and the proportion of coarse-particle-grade kernel carbon (+ 3 mm) is 19%. Mixing fine-fraction fuel and part of iron concentrate, pre-granulating (mixing mass ratio of the fine-fraction fuel to the part of iron concentrate is 1:6.5, granulating time is 2min, average particle size of the particles I is 2.82 mm), mixing the particles I with the rest raw materials, granulating for the second time to obtain granules II with conventional size, distributing the granules II onto sintering, distributing the granules II to 1000mm, igniting for 1min at 1050+/-50 ℃ and preserving heat for 1min, and sintering under negative pressure of 15 kPa. And uniformly injecting oxygen-enriched gas medium in the interval from the ignition end to the beginning of the rising of the exhaust gas temperature in the sintering process, wherein the oxygen concentration in the injected oxygen-enriched medium is 23.5%. The effects on the sintering index and the pollutant emission reduction effect after the method described in this example are shown in tables 1 and 2, respectively.
TABLE 1 sintering yield and quality index for different examples
TABLE 2 pollutant emission reduction ratios/%
| Scheme for the production of a semiconductor device | CO | CO 2 | NOx | SOx |
| Comparative example 1 (general sintering) | 0 | 0 | 0 | 0 |
| Comparative example 2 (oxygen-enriched free blowing) | 13 | 21 | 18 | 5 |
| Comparative example 3 (oxygen-enriched blowing of Whole coke powder) | 9 | 16 | 11 | 3 |
| Comparative example 4 (without pre-granulation) | 10 | 19 | 14 | 5 |
| Comparative example 5 (Whole section even blowing) | 18 | 21 | 15 | 6 |
| Example 1 | 22 | 18 | 20 | 7 |
| Example 2 | 29 | 23 | 17 | 9 |
| Example 3 | 35 | 26 | 19 | 10 |
Claims (6)
1. A sintered carbon emission reduction method based on efficient fuel combustion in an ultra-high material layer sintering process is characterized by comprising the following steps of: granulating the fine fraction fuel and part of the iron concentrate for the first time to obtain a pellet I; mixing the pellets I with raw materials including the rest part of iron ore, coarse-grain fuel, medium-grain fuel, flux and return ore, and performing secondary pelletization to obtain pellets II; sequentially carrying out super-thick cloth, ignition and sintering on the pellets II; in the sintering process, oxygen-enriched gas medium is sprayed to the surface of the sintering material between the end of ignition and heat preservation and the temperature rising point of sintering waste gas;
the coarse fraction fuel has a particle size composition of >3mm;
the granularity range of the medium-granularity fuel is 0.5-3 mm;
the fine fraction fuel has a particle size composition of <0.5mm;
the sintering material surface between the end of ignition and heat preservation and the temperature rising point of sintering waste gas is divided into three oxygen-enriched gas medium injection areas of an area-1, an area-2 and an area-3, wherein the lengths of the three areas account for 15% -25%, 60% -65% and 10% -25%;
the oxygen-enriched gas medium is a mixed gas formed by oxygen and air according to the volume ratio of 1:200-1:20;
the oxygen concentration in the oxygen-enriched gas medium sprayed in the area-1 is 22% -22.75%;
the oxygen concentration in the oxygen-enriched gas medium sprayed in the area-2 is 23% -24%;
the oxygen concentration in the oxygen-enriched gas medium sprayed in the area-3 is 21.5% -22%.
2. The method for reducing the emission of the sintered carbon based on the efficient fuel combustion in the ultra-high material layer sintering process according to claim 1, wherein the method is characterized by comprising the following steps of: the mass percentages of the fine-grade fuel, the medium-grade fuel and the coarse-grade fuel are as follows: 15-30%, 50-70%, 15-30%.
3. The method for reducing the emission of the sintered carbon based on the efficient combustion of the fuel in the ultra-high material layer sintering process according to claim 2, which is characterized in that:
the medium-grade fuel comprises at least one of coke powder, anthracite and semi-coke;
the fine fraction fuel comprises at least one of coke powder, anthracite and semi-coke;
the coarse fraction fuel comprises at least one of straw charcoal, sawdust charcoal, fruit kernel charcoal and charcoal.
4. The method for reducing the emission of the sintered carbon based on the efficient fuel combustion in the ultra-high material layer sintering process according to claim 1, wherein the method is characterized by comprising the following steps of: in the primary pelletization process, the mass ratio of the fine fraction fuel to the iron ore concentrate is 1:5-1:6.5, and the pelletization time is 1.5-3 min.
5. The method for reducing the emission of the sintered carbon based on the efficient fuel combustion in the ultra-high material layer sintering process according to claim 1, wherein the method is characterized by comprising the following steps of: the average particle size of the pellets I is 1-3 mm.
6. The method for reducing the emission of the sintered carbon based on the efficient fuel combustion in the ultra-high material layer sintering process according to claim 1, wherein the method is characterized by comprising the following steps of: the thickness of the material layer of the super-thick cloth is not less than 950mm.
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