CN106521144A - Method and system for reducing content of CO and nitric oxide in sintering waste gas - Google Patents
Method and system for reducing content of CO and nitric oxide in sintering waste gas Download PDFInfo
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- CN106521144A CN106521144A CN201610982181.1A CN201610982181A CN106521144A CN 106521144 A CN106521144 A CN 106521144A CN 201610982181 A CN201610982181 A CN 201610982181A CN 106521144 A CN106521144 A CN 106521144A
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- 238000005245 sintering Methods 0.000 title claims abstract description 265
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title claims abstract description 107
- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000002912 waste gas Substances 0.000 title abstract description 40
- 239000000463 material Substances 0.000 claims abstract description 112
- 238000002156 mixing Methods 0.000 claims abstract description 62
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000000446 fuel Substances 0.000 claims abstract description 44
- 238000009826 distribution Methods 0.000 claims abstract description 26
- 238000005507 spraying Methods 0.000 claims description 44
- 238000002347 injection Methods 0.000 claims description 19
- 239000007924 injection Substances 0.000 claims description 19
- 239000007921 spray Substances 0.000 claims description 16
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 239000000843 powder Substances 0.000 claims description 10
- 238000002360 preparation method Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 7
- 235000019738 Limestone Nutrition 0.000 claims description 6
- 239000000292 calcium oxide Substances 0.000 claims description 6
- 235000012255 calcium oxide Nutrition 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 239000006028 limestone Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 239000010459 dolomite Substances 0.000 claims description 5
- 229910000514 dolomite Inorganic materials 0.000 claims description 5
- 238000002485 combustion reaction Methods 0.000 abstract description 21
- 230000008569 process Effects 0.000 abstract description 19
- 239000004744 fabric Substances 0.000 description 20
- 230000000694 effects Effects 0.000 description 12
- 239000002245 particle Substances 0.000 description 12
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 7
- 239000000920 calcium hydroxide Substances 0.000 description 7
- 235000011116 calcium hydroxide Nutrition 0.000 description 7
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 238000004134 energy conservation Methods 0.000 description 5
- 230000035699 permeability Effects 0.000 description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 4
- 235000011941 Tilia x europaea Nutrition 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000003546 flue gas Substances 0.000 description 4
- 239000004571 lime Substances 0.000 description 4
- 238000012216 screening Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000003344 environmental pollutant Substances 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Classifications
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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
- C22B1/22—Sintering; Agglomerating in other sintering apparatus
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention provides a method and system for reducing the content of CO and nitric oxide in sintering waste gas. The method includes the steps that materials for sintering are prepared; the materials are primarily mixed, wherein the primary mixing time ranges from 2 min to 4 min; the materials are secondarily mixed, wherein the secondary mixing time ranges from 2 min to 4 min, and the water distribution amount of the secondarily-mixed materials ranges from 6.0% to 8.0%; the secondarily-mixed materials are laid on a sintering machine, wherein the laying thickness ranges from 400 mm to 1,000 mm; the ignition temperature of the sintering machine is controlled to range from 1,000 DEG C to 1,200 DEG C; and in a preset sintering region, remaining water is sprayed on the sintering material face of the sintering machine in a steam form through a humidifying device. Thus, the remaining water is added into the sintering materials in the manner that steam is sprayed to the sintering material face, the breathability of the sintering material face can be improved, complete combustion of sintering fuel is promoted, and therefore the content of CO in the sintering waste gas is reduced; and meanwhile, the steam is sprayed, so that generation of fuel type and thermal type nitric oxide in the sintering process is restrained, and the content of nitric oxide in the sintering waste gas can be reduced.
Description
Technical Field
The invention belongs to the technical field of iron-making material sintering, and particularly relates to a method and a system for reducing the contents of CO and nitrogen oxides in sintering waste gas.
Background
The agglomeration of the sinter is mainly provided by heat generated by fuel combustion, and C in the fuel is combusted from top to bottom in sequence under the action of air suction of a fan and transfers the heat, so that the sinter is bonded into the agglomerate.
In the production process of sintered ore, combustion due to C has both forms of complete combustion and incomplete combustion, and the amount of heat released by complete combustion is three times as much as that of incomplete combustion; therefore, improving the combustion efficiency of the sintering fuel is an important means for increasing the heat in the sintering process and reducing the fuel consumption; meanwhile, the fuel consumption is reduced, and pollutants in sintering waste gas can be reduced. But with CO2When the combustion efficiency of the fuel in the sintering process is evaluated by (CO + CO2), the CO content in the waste gas is up to 3 percent when the sintering waste gas composition is tested, and the CO2/(CO + CO) content is obtained2) It is about 75%, which means that CO is formed in 3 parts of 4 parts of C in the sintering fuel2And 1 part generates CO, which indicates that the utilization rate of the sintering fuel is low. And if CO can be increased2/(CO+CO2) Increasing the conversion of C to CO2The proportion of (3) is that the fuel consumption required by the same heating value is reduced, and the energy conservation and emission reduction are facilitated. Meanwhile, in the combustion process of C, steam is sprayed to reduce the highest temperature of a material layer, and the generation of fuel type and thermal type nitrogen oxides in the sintering process is inhibited in combination with the improvement of sintering combustion efficiency, so that the emission reduction of the nitrogen oxides in the waste gas is facilitated.
Based on the above, the present invention provides a method and a system for reducing CO and nitrogen oxides in sintering exhaust gas content, so as to solve the above problems in the prior art.
Disclosure of Invention
Aiming at the problems in the prior art, the embodiment of the invention provides a method and a system for reducing the contents of CO and nitrogen oxides in sintering waste gas, so as to solve the technical problems that in the prior art, the utilization rate of sintering fuel is low and pollutants in the sintering waste gas are increased due to incomplete combustion in the production process of sintering ores.
The invention provides a method for reducing the content of CO and nitrogen oxides in sintering waste gas, which comprises the following steps:
preparing materials for sintering;
mixing the materials for the first time;
after the materials are mixed for the second time, the water distribution amount of the materials is 6.0-8.0%;
laying the secondarily mixed materials on a sintering machine, wherein the laying thickness is 400-1000 mm;
controlling the ignition temperature of the sintering machine to be 1000-1200 ℃;
and spraying the residual water quantity of the humidifying device on the sintering charge surface on the sintering machine in a steam mode in a preset sintering area.
In the above scheme, the components of the material include:
50-80% of iron ore powder by mass;
10-30% of return fines by mass percent;
0-10% of quicklime by mass;
0-10% of dolomite by mass;
0-10% of limestone by mass;
the fuel accounts for 3-8% by mass.
In the above scheme, after the ignition temperature of the sintering machine is controlled to be 1000-1200 ℃, the method further comprises:
controlling the sintering negative pressure to be 7000-20000 Pa;
and controlling the ignition negative pressure to be 3000-15000 Pa.
In the scheme, the temperature of the steam is not less than 130 ℃.
The invention also provides a system for reducing the content of CO and nitrogen oxides in sintering waste gas, which comprises:
the preparation unit is used for preparing materials for sintering;
the first mixing unit is used for mixing the materials for the first time;
the second mixing unit is used for mixing the materials for the second time, and the water distribution amount of the materials after the second mixing is 6.0-8.0%;
the distribution unit is used for distributing the materials after the secondary mixing on a sintering machine, and the distribution thickness is 400-1000 mm;
the first control unit is used for controlling the ignition temperature of the sintering machine to be 1000-1200 ℃;
and the second control unit is used for controlling the humidifying device to spray the residual water quantity on the sintering charge surface on the sintering machine in a steam mode.
In the above aspect, the humidifying device includes:
the main pipeline is arranged on one side of the sintering machine;
one end of the branch pipe is connected with the main pipeline;
and the injection device is connected with the other end of each branch pipe and is positioned above the sintering charge level.
In the scheme, the distance between the injection device and the sintering charge level is 5-30 cm.
In the scheme, the spraying devices on the adjacent branch pipes are arranged in a crossed mode.
In the above scheme, the temperature of the steam is not less than 130 ℃.
In the above scheme, the distance between each branch pipe is 1-8 m.
The invention provides a method and a system for reducing the content of CO and nitrogen oxides in sintering waste gas, wherein the method comprises the following steps: preparing materials for sintering; mixing the materials for the first time; carrying out secondary mixing on the materials, wherein the water distribution amount of the materials after secondary mixing is 6.0-8.0%; laying the secondarily mixed materials on a sintering machine, wherein the laying thickness is 400-1000 mm; controlling the ignition temperature of the sintering machine to be 1000-1200 ℃; spraying the residual water quantity on the sintering charge surface on the sintering machine in a steam form by using a humidifying device in a preset sintering area; so, add remaining water volume to the sintering material through the mode of spraying steam to the sintering charge level, can improve the gas permeability of sintering charge level, promote the complete burning of sintering fuel, and then reduce the content of CO and nitrogen oxide in the sintering waste gas.
Drawings
FIG. 1 is a schematic flow chart of a method for reducing the contents of CO and nitrogen oxides in sintering exhaust gas according to an embodiment of the present invention;
fig. 2 is a schematic view of an overall structure of a humidifying device according to a first embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a system for reducing the contents of CO and nitrogen oxides in sintering exhaust gas according to a third embodiment of the present invention.
Detailed Description
In order to promote complete combustion of sintering fuel and further reduce the content of CO and nitrogen oxides in sintering waste gas in the production process of sintering ores, the invention provides a method and a system for reducing the content of CO and nitrogen oxides in sintering waste gas, wherein the method comprises the following steps: preparing materials for sintering; mixing the materials for the first time; carrying out secondary mixing on the materials, wherein the water distribution amount of the materials after secondary mixing is 6.0-8.0%; laying the secondarily mixed materials on a sintering machine, wherein the laying thickness is 400-1000 mm; controlling the ignition temperature of the sintering machine to be 1000-1200 ℃; and spraying the residual water quantity on the sintering charge surface on the sintering machine in a steam form by using a humidifying device in a preset sintering area.
The technical solution of the present invention is further described in detail by the accompanying drawings and the specific embodiments.
Example one
The present embodiment provides a method for reducing the content of sintering waste gas, as shown in fig. 1, the method comprising the steps of:
step 110, preparing materials for sintering.
In the step, materials required for sintering need to be prepared before sintering; before preparing materials, lime and water are prepared into slaked lime by using a digester, and the slaked lime is powder with stable components. When the material is prepared, 40-80% of the total mass of the fuel is added to the material in the dosing chamber.
Wherein the components of the material comprise: 50-80% of iron ore powder by mass; preferably 60-70%; 10-30% of return fines, preferably 15-25% by mass; 0-10% of quick lime, preferably 4-8%; 0-10% of dolomite, preferably 5-9% by mass; 0-10% of limestone, preferably 4-7% by mass; 3-8% of fuel by mass; wherein the fuel is generally coke powder.
And step 111, mixing the materials for the first time, wherein the mixing time for the first time is 2-4 min.
In the step, after the materials are prepared, the materials need to be mixed for one time, and the time for one-time mixing is 2-4 min, preferably 2.5-3.5 min.
And 112, carrying out secondary mixing on the materials, wherein the secondary mixing time is 2-4 min.
In the step, after the materials are subjected to primary mixing, the materials are subjected to secondary mixing to granulate the materials, wherein the secondary mixing time is 2-4 min; and the water distribution amount of the materials after the secondary mixing is 6.0-8.0% of the total water distribution amount. Wherein 20-60% of the total mass of the fuel is added to the material within the last 1min of the secondary mixing.
And 113, arranging the secondarily mixed materials on a sintering machine, wherein the arrangement thickness is 400-1000 mm.
In the step, after the materials are mixed, the materials after secondary mixing are uniformly distributed on a sintering machine, and the distribution thickness is 400-1000 mm, preferably 600-900 mm.
And 114, spraying the residual water quantity on the sintering charge surface of the sintering machine in a steam mode in a preset sintering area.
In the step, after the materials are uniformly distributed on the sintering machine, the ignition temperature of the sintering machine is controlled to be 1000-1200 ℃; controlling ignition negative pressure to be 3000-15000 Pa; and controlling the sintering negative pressure to be 7000-20000 Pa.
After the ignition temperature, the ignition negative pressure and the sintering negative pressure of the sintering machine are set, spraying the residual water quantity on the sintering charge surface of the sintering machine in a steam mode by using a humidifying device in a preset sintering area. Wherein the preset sintering area may include: the distance between the ignition position of the sintering machine and the ignition position of the sintering machine is 20-40 m, or the distance between the ignition position of the sintering machine and the ignition position of the sintering machine is 30-70 m.
Specifically, referring to fig. 2, the humidifying device includes: a main pipeline 1, a branch pipeline 2 and an injection device 3; wherein,
the main pipe 1 is provided at one side of the sintering machine to supply a water source or a steam source to the branch pipes 2. A preset distance is reserved between the branch pipe 2 and the ignition part 4 of the sintering machine; the distance cannot be too small to prevent the just formed sintered high temperature zone from being extinguished by water or steam; and the distance between the branch pipe 2 closest to the ignition position of the sintering machine and the ignition position 4 of the sintering machine can be set to be 10-15 m. Preferably 12 m.
One end of each branch pipe 2 is respectively connected with the main pipe 1, the branch pipe 2 comprises a plurality of branch pipes, and specifically can be: 8-40 roots; and the distance between the branch pipes 2 is 1-8 m.
The spraying devices 3 are respectively connected with the other end of each branch pipe 2, and the spraying devices 3 are positioned above the sintering charge level and used for spraying water or steam to the sintering charge level; wherein 4-10 injection devices 3 are respectively distributed on each branch pipe 2; the ejection device 3 may be in particular a spray head or a nozzle. Here, in order to ensure the spraying effect, the spraying devices 3 on adjacent branch pipes 2 are arranged in a cross manner.
Further, in the operation process of the sintering machine, the sintering fabric shrinks, the height of the sintering fabric on the sintering machine is gradually reduced, and in order to ensure the spraying effect, the distance between the spraying device 3 and the sintering fabric is kept between 5cm and 30cm all the time; preferably 20 cm. And, during spraying, the temperature of the spray steam is not less than 130 ℃.
During the sintering process, the total amount of sprayed water or steam can be 1-6t/h, and the water distribution amount in the sintering mixture before ignition is correspondingly reduced so as to ensure that the total water amount is constant.
In actual production, after the sintering machine is ignited for about 5 minutes, the valves on the branch pipes 2 are controlled to be opened, the spraying devices 3 start to uniformly spray the sintering fabric, and the spraying is stopped before the sintering abandon temperature is increased.
And after sintering is finished, reducing the temperature of the sintered ore to be not more than 200 ℃ by using a circular cooler. And screening the cooled sinter particles by using a vibrating screen with 5.0mm screen holes, wherein the undersize is sinter return ores, and the oversize is finished sinter ores. And detecting the conventional indexes of the sintering ore by using a detection instrument, and detecting sintering waste gas by using a flue gas analyzer. Wherein the conventional indicators include: the method comprises the following steps of drum index, yield of particles with the particle size of 5-10mm, yield of particles with the particle size of less than 5mm, solid burnup and content of nitrogen oxides NOx.
In the method for reducing sintering waste gas provided by the embodiment, after the sintering machine is ignited, steam is sprayed on the sintering fabric by using the spraying device, because of H2The appearance of O ensures that the combustion effect of the sintering fuel is better, improves the air permeability of a material layer, promotes the complete combustion of the fuel, and generates more CO2The generated CO is reduced, and the generation of fuel type and thermal type nitrogen oxides in the sintering process is favorably inhibited, so that the contents of the CO and the nitrogen oxides in the sintering waste gas are reduced, and the energy conservation and the consumption reduction are realized.
Example two
In accordance with a first embodiment, the present embodiment further provides a system for reducing the content of sintering waste gas, as shown in fig. 3, the system comprising: a preparation unit 31, a first mixing unit 32, a second mixing unit 33, a layout unit 34, a first control unit 35, and a second control unit 36; wherein,
the preparation unit 31 is used for preparing materials for sintering; specifically, before sintering, the preparation unit 31 needs to prepare materials required for sintering; before the preparation of the materials, the preparation unit 31 prepares lime, which is a powder with stable components, with water into slaked lime using a slaker. When preparing a material, the preparation unit 31 adds 40-80% of the total mass of fuel to the material in the dosing chamber.
The components of the material comprise: 50-80% of iron ore powder by mass; preferably 60-70%; 10-30% of return fines, preferably 15-25% by mass; 0-10% of quick lime, preferably 4-8%; 0-10% of dolomite, preferably 5-9% by mass; 0-10% of limestone, preferably 4-7% by mass; 3-8% of fuel by mass; wherein the fuel is generally coke powder.
After the preparation unit 31 prepares the materials, the first mixing unit 32 is used for mixing the materials for the first time, and the first mixing time is 2-4 min; preferably 2.5-3.5 min.
After the first mixing unit 32 performs primary mixing on the materials, the second mixing unit 33 is used for performing secondary mixing on the materials for granulation, the secondary mixing time is 2-4 min, and the water distribution amount of the materials after secondary mixing is 6.0-8.0% of the total water distribution amount; wherein the second mixing unit 33 is further adapted to add 20-60% of the total mass of the fuel to the mass during the last 1min of the second mixing.
After the materials are well mixed, the laying unit 34 is used for laying the materials after the secondary mixing on a sintering machine, and the laying thickness is 400-1000 mm; preferably 600-900 mm.
After the materials are distributed, the first control unit 35 is used for controlling the ignition temperature of the sintering machine to be 1000-1200 ℃; controlling ignition negative pressure to be 3000-15000 Pa; and controlling the sintering negative pressure to be 7000-20000 Pa.
After the ignition temperature, the ignition negative pressure and the sintering negative pressure of the sintering machine are all set, the second control unit 36 is used for controlling the humidifying device to spray the residual water quantity in the form of steam in a preset sintering area on the sintering material surface of the sintering machine, wherein the preset sintering area can comprise: the distance between the ignition position of the sintering machine and the ignition position of the sintering machine is 20-40 m, or the distance between the ignition position of the sintering machine and the ignition position of the sintering machine is 30-70 m.
Specifically, referring to fig. 2, the humidifying device includes: a main pipeline 1, a branch pipeline 2 and an injection device 3; wherein,
the main pipe 1 is provided at one side of the sintering machine to supply a water source or a steam source to the branch pipes 2. A preset distance is reserved between the branch pipe 2 and the ignition part 4 of the sintering machine; the distance cannot be too small to prevent the just formed sintered high temperature zone from being extinguished by water or steam; and the distance between the branch pipe 2 closest to the ignition position of the sintering machine and the ignition position 4 of the sintering machine can be set to be 10-15 m. Preferably 12 m.
One end of each branch pipe 2 is respectively connected with the main pipe 1, the branch pipe 2 comprises a plurality of branch pipes, and specifically can be: 8-40 roots; and the distance between the branch pipes 2 is 1-8 m.
The injection devices 3 are respectively connected with the other ends of the branch pipes 2, and the injection devices 3 are positioned above the sintering charge level and used for spraying steam to the sintering charge level; wherein 4-10 injection devices 3 are respectively distributed on each branch pipe 2; the ejection device 3 may be in particular a spray head or a nozzle. Here, in order to ensure the spraying effect, the spraying devices 3 on adjacent branch pipes 2 are arranged in a cross manner.
Further, in the operation process of the sintering machine, the sintering fabric shrinks, the height of the sintering fabric on the sintering machine is gradually reduced, and in order to ensure the spraying effect, the distance between the spraying device 3 and the sintering fabric is kept between 5cm and 30cm all the time; preferably 20 cm. And, during spraying, the temperature of the spray steam is not less than 130 ℃.
During the sintering process, the total amount of sprayed water or steam can be 1-6t/h, and the water distribution amount in the sintering mixture before ignition is correspondingly reduced so as to ensure that the total water amount is constant.
In actual production, after the sintering machine is ignited for about 5 minutes, the second control unit controls the valves on the branch pipes 2 in the preset sintering area to be opened, the injection devices 3 start to uniformly spray the sintering fabric, and the spraying is stopped before the sintering abandon temperature is increased.
And after sintering is finished, reducing the temperature of the sintered ore to be not more than 200 ℃ by using a circular cooler. And screening the cooled sinter particles by using a vibrating screen with 5.0mm screen holes, wherein the undersize is sinter return ores, and the oversize is finished sinter ores. And detecting the conventional indexes of the sintering ore by using a detection instrument, and detecting sintering waste gas by using a flue gas analyzer. Wherein the conventional indicators include: the method comprises the following steps of drum index, yield of particles with the particle size of 5-10mm, yield of particles with the particle size of less than 5mm, solid burnup and content of nitrogen oxides NOx.
In practical applications, the configuration Unit 31, the first mixing Unit 32, the second mixing Unit 33, the layout Unit 34, the first control Unit 35, and the second control Unit 36 may be implemented by a Central Processing Unit (CPU), a Digital Signal Processor (DSP), a programmable logic Array (FPGA), and a Micro Control Unit (MCU) in the apparatus.
In the system for reducing the content of sintering waste gas provided by this embodiment, after the sintering machine is ignited, the injection device is controlled to spray steam to the sintering fabric in the preset area, because of H2The appearance of O ensures that the combustion effect of the sintering fuel is better, improves the air permeability of a material layer, promotes the complete combustion of the fuel, and generates more CO2The generated CO is reduced, and the generation of fuel type and thermal type nitrogen oxides in the sintering process is favorably inhibited, so that the contents of the CO and the nitrogen oxides in the sintering waste gas are reduced, and the energy conservation and the consumption reduction are realized.
EXAMPLE III
In practical application, when the method for reducing the content of the waste gas provided in the first embodiment and the system for reducing the content of the waste gas provided in the second embodiment are used for producing the sintered ore, the specific steps are as follows:
before sintering, preparing materials required for sintering; before preparing materials, lime and water are prepared into slaked lime by using a digester, and the slaked lime is powder with stable components. When the material is prepared, 2% by mass of fuel is added to the material in the batching chamber.
Wherein the components of the material comprise: 64 percent of iron ore powder by mass; return fines, the mass percent of which is 24%; quicklime with the mass percent of 4 percent; limestone, the mass percent of which is 5 percent; 3% of fuel by mass; wherein the fuel is generally coke powder.
When the materials are prepared, the materials need to be mixed for one time, and the time for one-time mixing is 2 min.
After the materials are subjected to primary mixing, the materials are subjected to secondary mixing for 3 min; and the water distribution amount of the materials after the secondary mixing is 6.5-7.0% of the total water distribution amount. Wherein, fuel with the mass percentage of 1 percent is added into the material within the last 1min of the secondary mixing.
And after the materials are well mixed, uniformly distributing the materials after secondary mixing on a sintering machine, wherein the distribution thickness is 800 mm.
After the materials are uniformly distributed on the sintering machine, controlling the ignition temperature of the sintering machine to be 1050 ℃; the ignition time is 3min, and the ignition negative pressure is controlled to be 9000 Pa; when the coke powder in the material starts to burn, the sintering negative pressure is controlled to be 150000 Pa.
In the sintering process, in a sintering area which is 20-40 m away from the ignition position of the sintering machine, the residual water is sprayed on the sintering charge surface of the sintering machine in a steam mode by using a humidifying device. Specifically, referring to fig. 2, the humidifying device includes: a main pipeline 1, a branch pipeline 2 and an injection device 3; wherein,
the main pipe 1 is provided at one side of the sintering machine to supply a water source or a steam source to the branch pipes 2. A preset distance is reserved between the branch pipe 2 and the ignition part 4 of the sintering machine; the distance cannot be too small to prevent the just formed sintered high temperature zone from being extinguished by water or steam; and the distance between the branch pipe 2 closest to the ignition position of the sintering machine and the ignition position 4 of the sintering machine can be set to be 10-15 m. Preferably 10 m.
One end of each branch pipe 2 is respectively connected with the main pipe 1, the branch pipe 2 comprises a plurality of branch pipes, and specifically can be: 8-40, 6 are opened in this embodiment; and the distance between the branch pipes 2 is 4 m.
The spraying devices 3 are respectively connected with the other end of each branch pipe 2, and the spraying devices 3 are positioned above the sintering charge level and used for spraying water or steam to the sintering charge level; wherein 4-10 injection devices 3 are respectively distributed on each branch pipe 2; the ejection device 3 may be in particular a spray head or a nozzle. Here, in order to ensure the spraying effect, the spraying devices 3 on adjacent branch pipes 2 are arranged in a cross manner.
Further, in the operation process of the sintering machine, the sintering fabric shrinks, the height of the sintering fabric on the sintering machine is gradually reduced, and in order to ensure the spraying effect, the distance between the spraying device 3 and the sintering fabric is kept between 5cm and 30cm all the time; preferably 20 cm. And, during spraying, the temperature of the spray steam is not less than 130 ℃.
During the sintering process, the total amount of sprayed water or steam can be 2t/h, and the water distribution amount in the sintering mixture before ignition is correspondingly reduced so as to ensure that the total water amount is constant.
In actual production, after the sintering machine is ignited for about 5 minutes, the valves on the corresponding branch pipes 2 are controlled to be opened, each injection device 3 starts to uniformly spray the sintering fabric, and the spraying is stopped before the sintering abandon temperature is increased.
And after sintering is finished, reducing the temperature of the sintered ore to be not more than 200 ℃ by using a circular cooler. And screening the cooled sinter particles by using a vibrating screen with 5.0mm screen holes, wherein the undersize is sinter return ores, and the oversize is finished sinter ores. And detecting the conventional indexes of the sintering ore by using a detection instrument, and detecting sintering waste gas by using a flue gas analyzer. Wherein, the conventional indexes are generally as follows: barrate index, solid burnup, return fines rate, ore grain diameter (including 5-10mm and <5 mm); the sintering exhaust gas mainly comprises nitrogen oxides NOx; and compared with the sintering process in the prior art, the comparison result is shown in table 1:
TABLE 1
As can be seen from table 1, the content of nitrogen oxides in the sintering waste gas was significantly reduced in this example.
In the embodiment, by using the method for reducing the content of CO and nitrogen oxides in the sintering waste gas provided by the embodiment, after the sintering machine is ignited, steam is sprayed on the sintering fabric in the sintering area 20-40 m away from the ignition position of the sintering machine by using the injection device, and H is used for reducing the content of CO and nitrogen oxides in the sintering waste gas2The appearance of O ensures that the combustion effect of the sintering fuel is better, improves the air permeability of a material layer, promotes the complete combustion of the fuel, and generates more CO2And the generated CO is reduced, so that the contents of CO and nitrogen oxides in the sintering waste gas are reduced, and energy conservation and consumption reduction are realized.
Example four
Corresponding to the third embodiment, when the method for reducing the content of the waste gas provided in the first embodiment and the system for reducing the content of the waste gas provided in the second embodiment are used to produce the sintered ore, the following steps are specifically performed:
before sintering, preparing materials required for sintering; before preparing materials, lime and water are prepared into slaked lime by using a digester, and the slaked lime is powder with stable components. When the material is prepared, 2% by mass of fuel is added to the material in the batching chamber.
Wherein the components of the material comprise: 64 percent of iron ore powder by mass; return fines, the mass percent of which is 24%; quicklime with the mass percent of 4 percent; 2% of dolomite in percentage by mass; limestone, the mass percent of which is 3 percent; 3% of fuel by mass; wherein the fuel is generally coke powder.
When the materials are prepared, the materials need to be mixed for one time, and the time for one-time mixing is 3 min.
After the materials are subjected to primary mixing, performing secondary mixing on the materials for granulation, wherein the secondary mixing time is 4 min; and the water distribution amount of the materials after the secondary mixing is 6.8-7.8% of the total water distribution amount. Wherein, fuel with the mass percentage of 1 percent is added into the material within the last 1min of the secondary mixing.
And after the materials are mixed well, uniformly distributing the materials after secondary mixing on a sintering machine, wherein the distribution thickness is 900 mm.
After the materials are uniformly distributed on the sintering machine, controlling the ignition temperature of the sintering machine to 1150 ℃; the ignition time is 4min, and the ignition negative pressure is controlled to be 10000 Pa; when the coke powder in the material starts to burn, the sintering negative pressure is controlled to be 160000 Pa.
In the sintering process, in a sintering area which is 30-70 m away from the ignition position of the sintering machine, the residual water is sprayed on the sintering charge surface of the sintering machine in a steam mode by using a humidifying device. Specifically, referring to fig. 2, the humidifying device includes: a main pipeline 1, a branch pipeline 2 and an injection device 3; wherein,
the main pipe 1 is provided at one side of the sintering machine to supply a water source or a steam source to the branch pipes 2. A preset distance is reserved between the branch pipe 2 and the ignition part 4 of the sintering machine; the distance cannot be too small to prevent the just formed sintered high temperature zone from being extinguished by water or steam; and the distance between the branch pipe 2 closest to the ignition position of the sintering machine and the ignition position 4 of the sintering machine can be set to be 10-15 m. Preferably 10 m.
One end of each branch pipe 2 is respectively connected with the main pipe 1, the branch pipe 2 comprises a plurality of branch pipes, and specifically can be: 8-40, this example opens 9; and the distance between the branch pipes 2 is 4.5 m.
The spraying devices 3 are respectively connected with the other end of each branch pipe 2, and the spraying devices 3 are positioned above the sintering charge level and used for spraying water or steam to the sintering charge level; wherein 4-10 injection devices 3 are respectively distributed on each branch pipe 2; the ejection device 3 may be in particular a spray head or a nozzle. Here, in order to ensure the spraying effect, the spraying devices 3 on adjacent branch pipes 2 are arranged in a cross manner.
Further, in the operation process of the sintering machine, the sintering fabric shrinks, the height of the sintering fabric on the sintering machine is gradually reduced, and in order to ensure the spraying effect, the distance between the spraying device 3 and the sintering fabric is kept between 5cm and 30cm all the time; preferably 15 cm. And, during spraying, the temperature of the spray steam was 150 ℃.
During the sintering process, the total amount of sprayed water or steam can be 2t/h, and the water distribution amount in the sintering mixture before ignition is correspondingly reduced so as to ensure that the total water amount is constant.
In actual production, after the sintering machine is ignited for about 5 minutes, the valves on the corresponding branch pipes 2 are controlled to be opened, each injection device 3 starts to uniformly spray the sintering fabric, and the spraying is stopped before the sintering abandon temperature is increased.
And after sintering is finished, reducing the temperature of the sintered ore to be not more than 200 ℃ by using a circular cooler. And screening the cooled sinter particles by using a vibrating screen with 5.0mm screen holes, wherein the undersize is sinter return ores, and the oversize is finished sinter ores. And detecting the conventional indexes of the sintering ore by using a detection instrument, and detecting sintering waste gas by using a flue gas analyzer. Wherein, the conventional indexes are generally as follows: barrate index, solid burnup, return fines rate, ore grain diameter (including 5-10mm and <5 mm); the sintering exhaust gas mainly comprises nitrogen oxides NOx; and compared with the sintering process in the prior art, the comparison result is shown in table 2:
TABLE 2
As can be seen from table 2, the content of nitrogen oxides in the sintering waste gas was significantly reduced in this example.
In the embodiment, by using the method for reducing the content of CO and nitrogen oxides in the sintering waste gas provided by the embodiment, after the sintering machine is ignited, steam is sprayed on the sintering fabric in the sintering area which is 30-70 m away from the ignition position of the sintering machine by using the injection device, and H is used for reducing the content of CO and nitrogen oxides in the sintering waste gas2The appearance of O ensures that the combustion effect of the sintering fuel is better, improves the air permeability of a material layer, promotes the complete combustion of the fuel, and generates more CO2The generated CO is reduced, and the generation of fuel type and thermal type nitrogen oxides in the sintering process is favorably inhibited, so that the contents of the CO and the nitrogen oxides in the sintering waste gas are reduced, and the energy conservation and the consumption reduction are realized.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (10)
1. A method for reducing the CO and nitrogen oxide content of sintering exhaust gas, comprising:
preparing materials for sintering;
mixing the materials for the first time;
after the materials are mixed for the second time, the water distribution amount of the materials is 6.0-8.0%;
laying the secondarily mixed materials on a sintering machine, wherein the laying thickness is 400-1000 mm;
controlling the ignition temperature of the sintering machine to be 1000-1200 ℃;
and spraying the residual water quantity of the humidifying device on the sintering charge surface on the sintering machine in a steam mode in a preset sintering area.
2. The method of claim 1, wherein the composition of the material comprises:
50-80% of iron ore powder by mass;
10-30% of return fines by mass percent;
0-10% of quicklime by mass;
0-10% of dolomite by mass;
0-10% of limestone by mass;
the fuel accounts for 3-8% by mass.
3. The method according to claim 1, wherein after controlling the ignition temperature of the sintering machine to be 1000 to 1200 ℃, the method further comprises:
controlling the sintering negative pressure to be 7000-20000 Pa;
and controlling the ignition negative pressure to be 3000-15000 Pa.
4. The method of claim 1, wherein the steam has a temperature of not less than 130 ℃.
5. A system for reducing CO and nitrogen oxide content in sintering exhaust, the system comprising:
the preparation unit is used for preparing materials for sintering;
the first mixing unit is used for mixing the materials for the first time;
the second mixing unit is used for mixing the materials for the second time, and the water distribution amount of the materials after the second mixing is 6.0-8.0%;
the distribution unit is used for distributing the materials after the secondary mixing on a sintering machine, and the distribution thickness is 400-1000 mm;
the first control unit is used for controlling the ignition temperature of the sintering machine to be 1000-1200 ℃;
and the second control unit is used for controlling the humidifying device to spray the residual water quantity on the sintering charge surface on the sintering machine in a steam mode.
6. The system of claim 5, wherein the humidifying device comprises:
the main pipeline is arranged on one side of the sintering machine;
one end of the branch pipe is connected with the main pipeline;
and the injection device is connected with the other end of each branch pipe and is positioned above the sintering charge level.
7. The system of claim 6, wherein the distance between the injector and the sintering level is 5-30 cm.
8. The system of claim 6, wherein the ejection devices on adjacent manifolds are in a cross-type arrangement.
9. The system of claim 6, wherein the temperature of the steam is not less than 130 ℃.
10. The system of claim 6, wherein the distance between the branch pipes is 1 to 8 m.
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