Method for realizing smooth strengthening in blow-in process of blast furnace
By controlling the coke particle size at the bottom of the furnace, the overall coke ratio, and the sleeper filling method, optimizing the blast ventilation strategy, and setting up sand dams, the difficulties and hanging problems during blast furnace start-up were solved, achieving smooth and enhanced blast furnace start-up and increased slag and iron temperature, while reducing the cost and workload of subsequent processes.
Patent Information
- Application Number
- CN202511043474.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-28
- Publication Date
- 2025-11-18
AI Technical Summary
During the blast furnace start-up process, how to achieve smooth intensification and avoid accidents such as difficulty in operation and material suspension, especially in large-scale blast furnaces, how to adapt to changes in thermal state, gas flow distribution and material state, and especially the problem of deterioration of permeability during the formation of the softening zone.
By controlling the particle size of the bottom coke and the overall coke ratio in the furnace, optimizing the sleeper filling method, adjusting the air supply strategy, setting up sandbars to extend the slag spraying time at the taphole, and quickly opening the taphole for heat exchange before air supply, combined with laser measurement and precise material distribution angle, an airflow protection zone is formed, thus optimizing the distribution of materials and gas in the furnace.
It effectively improves the heat exchange effect between the hearth and the gas, increases the temperature of slag and iron, reduces the desulfurization and slag transportation costs in the steelmaking process, reduces the workload of furnace workers, and ensures the smooth flow of slag and iron.
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of blast furnace, and particularly relates to a method for realizing smooth strengthening in the process of starting up a blast furnace. BACKGROUND
[0002] One of the tasks of starting up a blast furnace is to gradually strengthen, and it is required that no accidents such as difficult running and even hanging material occur in the process of strengthening, which affects the strengthening process. The premise for realizing the above purpose is that the blast furnace thermal state at the key time node, the gas flow distribution and the change of the material state in the blast furnace are adapted to the characteristics of the deteriorating permeability during the formation of the soft melting zone. With the continuous expansion of the blast furnace volume, it is required that the starting up technology can adapt to the characteristics of the large-scale blast furnace, such as the need for more accurate control in the aspects of starting up burden calculation, charging, strengthening and the like. How to adjust the charging system of the upper part of the blast furnace and the optimized arrangement of various materials to make the blast furnace charge and the coal gas distribution reasonably matched. For example, the selection of the charging method and sequence when starting up, how to form a reasonable column structure, and lay a good foundation for the subsequent gas flow distribution and stable furnace condition, which is particularly important in the process of starting up. SUMMARY
[0003] The purpose of the present application is to provide a method for realizing smooth strengthening in the process of starting up a blast furnace, preventing difficult running and hanging material, and after adopting the method, the furnace condition can be steadily and smoothly strengthened.
[0004] To solve the above technical problems, the present application adopts the following technical scheme:
[0005] The present application is a method for realizing smooth strengthening in the process of starting up a blast furnace, comprising:
[0006] 1) After the completion of the blast furnace drying, 600-1000mm bottom paving coke is loaded at the furnace bottom, and dry coke without using coke with too large particle size is selected;
[0007] 2) The total coke ratio of the starting up charge is controlled at 3.3-3.5t / t, the total basicity of the blast furnace is controlled at 0.9-0.95, and the empty coke basicity is controlled at 0.88-0.90;
[0008] 3) In the calculation of the total basicity of the blast furnace, the coke amount of the center coke pile is all excluded and does not participate in the basicity calculation; the net coke is loaded in the bosh, and the empty coke is loaded from the bosh to the lower part of the shaft considering the requirement of slagging; the limestone is used to dilute the Al2O3 content in the slag to 12%-14% together with the silica;
[0009] 4) In the calculation and arrangement of the load-bearing material at the lower part of the shaft, in order to control the weighing accuracy, no ore batch with O / C<0.1 is arranged; the load-bearing material at the shaft is arranged from O / C=0.2, and the position of the load-bearing material is further raised;
[0010] 5) The arrangement of the load-bearing material gradually reduces the batch number from light to heavy:
[0011] 6) The last batch of net coke in the bosh is arranged as follows: the chute is placed at the smallest angle, and all is arranged in the center position to form a coke tip; the last batch of empty coke in the lower part of the shaft is also arranged in the center position to form an empty coke tip, so that the subsequent load carrying material will not invade the center material column after a long empty zone travel, thus forming protection for the center gas passage;
[0012] 7) All bulk pallets above the bottom coke up to the center line below the tuyere are laid, but the filling rate needs to be calculated by the volume of the laid pallets and the elevation markers arranged in the furnace during the filling process, and the filling rate is controlled at 0.52-0.55; the pallets are densely laid starting from 600mm away from the center line of the tuyere, and the densely laid pallets in the center area of the hearth are controlled to have a gap of <25mm; the density of the pallets needs to be controlled at 750-850kg / m 3 ;
[0013] 8) The material chute is installed after the installation of the pallets; the laser measurement method is used to measure the material angle and the coke trajectory during the installation of the net coke in the bosh; the last batch of net coke in the bosh, the last batch of empty coke in the shaft, and the previous batch during the measurement of the ore inner ring angle are all arranged in the center area to create a gas flow protection area; the single ring is changed to multiple rings for material distribution starting from the bosh, and the coke is leveled;
[0014] 9) Before blowing, all the iron ports are quickly opened to strengthen the lower heat exchange and quickly heat the hearth;
[0015] 10) After blowing, at least one top gas discharge valve is closed to increase the upward gas resistance, so as to increase the gas flow into the hearth;
[0016] 11) The air volume is 30-40% of the total air volume, and the air volume is gradually and slowly increased to 60-65% 9h after blowing, and maintained for 3-6h before slowly increasing the air volume;
[0017] 12) The air volume is controlled at 75% of the normal air volume when the first iron is discharged.
[0018] Further, equipment is used to strengthen the heat exchange between high temperature gas and bottom coke, to prevent a large amount of gas from being directly discharged from the iron port without the equipment, which is difficult to heat to the bottom coke.
[0019] Further, when the bottom coke is installed, the material chute does not need to be installed, so as to prevent the safety hazards caused by the chute during the leveling of the bottom coke and the laying of the pallets.
[0020] Further, when laying the pallets, the requirements can be appropriately relaxed in the edge area close to the tuyere area if the construction period is tight.
[0021] Further, the density of the pallets is controlled at 800kg / m 3 .
[0022] Further, in the 10), the number of open valves is not more than 50%.
[0023] Further, sand dams are arranged in front of all main channels, and the slag spouting from the taphole fills the main channel in front of the temporary sand dam, and then the taphole is closed, thereby prolonging the slag spouting time of the taphole and heating the lower part of the hearth, especially the taphole channel region.
[0024] Compared with the prior art, the beneficial technical effects of the present application are:
[0025] The present application communicates a method for successfully strengthening the blast furnace blow-in process, avoiding difficult operation and hanging material. A series of measures are taken in the blast furnace blow-in process, including controlling the particle size of the bottom coke, controlling the total furnace coke ratio, optimizing the sleeper filling method, quickly opening the taphole after air supply to eliminate the dead zone of the hearth gas circulation, setting up the main channel sand dam to prolong the taphole slag spouting time, and the like. Through the establishment of the above control points, the heat exchange effect of the hearth and the gas can be effectively improved, the slag-iron temperature can be effectively increased in the early stage of the total furnace coke ratio, the hot metal
Si
S
[0026] A method for successfully strengthening the blast furnace blow-in process, comprising:
[0027] 1. After the completion of the blast furnace drying, 600-1000mm bottom coke is loaded on the hearth, dry coke is selected, and coke with too large particle size is not used; when loading the bottom coke, a material distribution chute does not need to be loaded. This measure can prevent safety hazards caused by the chute during the rake bottom coke and the placement of sleepers.
[0028] 2. The total furnace coke ratio of the blow-in material is controlled at 3.3-3.5t / t, the total furnace basicity is controlled at 0.9-0.95, and the empty coke basicity is controlled at 0.88-0.90.
[0029] 3. When calculating the total furnace basicity, the center coke pile coke amount is all excluded and does not participate in the basicity calculation. Pure coke is loaded in the bosh, and empty coke is loaded from the bosh to the lower part of the shaft considering the slag making demand. Limestone is used to cooperate with silica to dilute the Al2O3 content in the slag to 12%-14%.
[0030] 4. In the calculation and arrangement of the load-bearing material in the lower part of the shaft, in order to control the weighing accuracy, no ore batch with O / C<0.1 is arranged. The load-bearing material in the shaft is arranged from O / C=0.2, and the load-bearing material position is further raised.
[0031] 5. The load-bearing material arrangement should gradually reduce the batch number from light to heavy.
[0032] 6. The last batch of net coke in the furnace belly is arranged as follows: the chute is placed at the smallest angle, and all the net coke is arranged in the center to form a coke pile. The last batch of empty coke in the lower part of the shaft is also arranged in the center to form an empty coke pile, so that the subsequent load will not invade the center column after a long empty area, thereby protecting the center gas passage.
[0033] 7. All bulk wood blocks are arranged above the bottom coke up to the center line below the tuyere, but the filling rate needs to be calculated by the elevation marks set in the furnace and the volume of the wood blocks during the filling process, and the filling rate is controlled at 0.52-0.55. The wood blocks are densely arranged at a distance of 600mm from the center line of the tuyere, and the gap between the densely arranged wood blocks in the center area of the hearth is controlled to be less than 25mm. If the construction period is tight, the requirement can be appropriately relaxed near the tuyere area in the edge area. The density of the wood blocks needs to be controlled at 800kg / m 3 . The above measures are taken to prevent the wood blocks from igniting after the air is sent, and to prevent the center from collapsing due to low filling rate or low wood density, and to prevent the upper load from moving to the center and sliding into the center area of the upper column, thereby blocking the main passage of the softening zone.
[0034] 8. After the wood blocks are installed, the material distribution chute is installed. When the net coke in the furnace belly is installed, the laser measurement method is used to measure the material distribution angle and the coke trajectory. The last batch of net coke in the furnace waist, the last batch of empty coke in the shaft, and the previous batch when measuring the ore inner ring angle are all arranged in the center area to create a gas flow protection area. From the beginning of the furnace waist, the material distribution changes from single ring to multiple rings, and the coke is leveled.
[0035] 9. Before the air is sent, all the iron ports are quickly opened to strengthen the lower heat exchange and quickly heat the hearth.
[0036] 10. After the air is sent, 1-2 furnace top gas discharge valves can be closed (the number of closed valves is controlled to be no more than 50%), and the upward gas resistance is increased to increase the gas flow into the hearth. A sand dam is set in front of all the main ditch sand ports, and the main ditch in front of the temporary sand dam is filled with slag spouted from the iron port before the port is closed, thereby prolonging the slag spouting time of the iron port and heating the lower part of the hearth, especially the iron port channel area.
[0037] 11. The air is sent at about 35% of the total air volume, and the air volume is gradually and slowly increased to 60-65% 9h after the air is sent, and maintained for 3-6h before the air is slowly and gradually increased.
[0038] 12. The air volume is controlled at 75% of the normal air volume when the first iron is tapped.
[0039] Case:
[0040] 1. After the completion of the furnace heating, start to load the opening furnace material, select the normal particle size of dry coke (not select large particle size coke) for the bottom coke, lay 1000mm thick at the bottom of the hearth, which can strengthen the heat exchange of the entering gas and the bottom coke, so as to increase the temperature of the bottom coke under the same gas quantity and the same gas temperature.
[0041] 2. The total furnace coke ratio is set at 3.5t / t. The total furnace R is controlled at 0.94, and the empty coke basicity is controlled at 0.9.
[0042] 3. Fill the net coke at the bosh position of the blast furnace, fill the empty coke at the bosh position, and fill the 286m 3 empty coke at the lower part of the shaft. The Al2O3 content in the slag of the total furnace opening furnace material is controlled at 12.3% by adding limestone + silica, and the Al2O3 content in the lower part of the load material is controlled at 10.0%. Slowly reduce the addition of limestone and silica to gradually increase the Al2O3 content, and control the highest at below 16.0%. This control method can improve the fluidity of the first iron slag and reduce the total furnace slag ratio, and further reduce the heat loss of the hearth.
[0043] 4. After the bottom coke is loaded and leveled, a layer of short sleepers (sleeper size: 0.8-1.0m*0.2m*0.16m) is densely laid on the bottom coke, and then the short sleepers are filled in a bulk manner. The short sleepers are densely arranged at a distance of about 600mm from the tuyere. The smaller size sleepers are used in combination with the upper and lower dense laying to improve the filling rate of the hearth and reduce the replacement speed of the upper part of the coke.
[0044] In the calculation and arrangement of the load material at the lower part of the shaft, in order to control the weighing accuracy, no ore batch with O / C<0.1 is arranged. The load material at the shaft is arranged from O / C=0.2, and the load material position is further raised.
[0045] 5. The O / C of the load material is gradually increased from 0.1 to 2.2 in steps of 0.1-0.3, and the corresponding batch number is gradually reduced from 6 batches to 1 batch.
[0046] 6. The chute is placed at 4° to arrange the last batch of net coke at the bosh and the last batch of empty coke at the lower part of the shaft.
[0047] 7. The sleeper filling rate is 0.53.
[0048] 8. The last batch of net coke at the bosh, the last batch of net coke at the lower part of the shaft, and the coke before the test of the most inner ring ore angle are all arranged with the material chute at 4°.
[0049] 9. Open all four iron mouths 30 minutes before blowing.
[0050] 10. Close one of the top diffusers after blowing.
[0051] 11. The slag spouted from the hole is accumulated in the main groove, and when the slag surface is less than 10 cm from the lower edge of the hole, the hole is blocked.
[0052] 12. The air volume is 2400 m 3 / min, and the air volume is gradually increased to 4100 m 3 / min 9 hours after the air supply, and maintained for 3 hours, and then the air is gradually increased.
[0053] The air volume is 4800 m 3 / min when the first iron is discharged.
[0054] After the above measures are adopted in the case, the slag-iron temperature is sufficient, the production is achieved in three days, and there is no suspended material in the blowing process.
[0055] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.
Claims
1. A method for achieving smooth and strong strengthening in the blow-in process of a blast furnace, characterized by, Comprise: 1) After the completion of the furnace, 600-1000mm of bottom coke is loaded on the furnace bottom, dry coke is selected and coke with large particle size is not used; 2) The total coke ratio of the starting material is controlled at 3.3-3.5t / t, the total basicity of the furnace is controlled at 0.9-0.95, and the empty coke basicity is controlled at 0.88-0.90; 3) In the calculation of the total basicity of the furnace, the center coke pile coke amount is all excluded and does not participate in the basicity calculation; pure coke is loaded in the bosh, and empty coke is loaded from the waist to the lower part of the shaft to meet the slag making requirement; limestone is used to dilute the Al2O3 content in the slag to 12%-14% together with silica; 4) In the calculation and arrangement of the load-bearing material in the lower part of the shaft, in order to control the weighing accuracy, no ore batch with O / C<0.1 is arranged; the load-bearing material in the shaft is arranged from O / C=0.2, further raising the load-bearing material position; 5) The arrangement of the load-bearing material should gradually reduce the batch number from light to heavy: 6) In the arrangement of the last batch of pure coke loaded in the bosh: the chute is placed at the smallest angle, all arranged in the center position to form a pile tip; the last batch of empty coke in the lower part of the shaft is also arranged in the center position to form an empty coke pile tip, so that the subsequent load-bearing material will not invade the center material column after a long empty area travel, forming a protection for the center gas channel; 7) all bulked sleepers from the bottom to the center line of the tuyere below, but the filling rate needs to be calculated by the elevation marks set in the furnace and the volume of sleepers loaded in the filling process, and the filling rate is controlled at 0.52-0.55; the sleepers are densely packed at a distance of 600mm from the center line of the tuyere, and the gap between the densely packed sleepers in the center area of the hearth is controlled to be less than 25mm; the sleeper density needs to be controlled at 750-850kg / m 3 ; 8) After the installation of the sleeper, the material distribution chute is installed; during the loading of the pure coke in the bosh, the method of laser measurement is used to measure the distribution angle and coke trajectory; the last batch of pure coke in the waist, the last batch of empty coke in the shaft, and the previous batch when measuring the ore inner ring angle are all arranged in the center area to create a gas flow protection area; start from the waist to change from single ring to multi-ring distribution and flatten the coke; 9) Before blowing, quickly open all the tuyeres to strengthen the lower heat exchange and quickly heat the hearth; 10) After blowing, close at least one top gas discharge valve to increase the upward gas resistance to increase the gas flow into the hearth; 11) According to 30-40% of the total air volume, the air volume is gradually increased to 60-65% 9h after blowing, maintained for 3-6h, and then slowly increased; 12) The air volume is controlled at 75% of the normal air volume when the first iron is discharged.
2. The method for achieving smooth and strong enhancement of the blow- up process of a blast furnace according to claim 1, characterized by, Use equipment to strengthen the heat exchange between high temperature gas and bottom coke, prevent a large amount of gas from being directly discharged from the tuyere without installing the equipment, and make it difficult to heat the bottom coke.
3. The method for achieving smooth and strong enhancement of the blow- up process of a blast furnace according to claim 1, characterized by, When loading the bottom coke, the material distribution chute does not need to be installed in order to prevent safety hazards caused by the chute during the process of entering the rake to flatten the bottom coke and placing the sleeper.
4. The method for achieving smooth and strong enhancement of the blow- up process of a blast furnace according to claim 1, characterized by, When laying the sleeper, if the construction period is tight, the requirement can be appropriately relaxed in the edge area close to the tuyere area.
5. The method for achieving smooth and strong enhancement of the blow- up process of a blast furnace according to claim 1, characterized by, Control the density of the sleepers at 800 kg / m 3 .
6. The method of achieving smooth and strong ramp-up of the blast furnace start-up process as claimed in claim 1 wherein, In the 10), the number of closed discharge valves does not exceed 50%.
7. The method of achieving smooth and strong ramp-up of the blast furnace start-up process as claimed in claim 1 wherein, Sand barriers are set in front of all main channels, and the main channel in front of the temporary sand barrier is filled with slag sprayed from the tuyere before the closing operation is performed, prolonging the iron port slag spraying time to make the lower part of the hearth, especially the tuyere channel area, well heated.