A method for controlling the first iron tapping during the opening of a large blast furnace

Abstract

A method for controlling the first iron tapping after the opening of a large blast furnace, by controlling the time of the first iron mouth opening, realizes the first iron tapping after the furnace is opened, in which molten iron is discharged first and then primary slag is discharged. A method for controlling the first iron tapping after the opening of a large blast furnace of the present invention, firstly, by establishing control over the time of the first iron mouth opening, realizes the iron tapping as soon as the iron mouth is opened, and forms the first iron tapping in which molten iron is discharged first and then primary slag is discharged after the furnace is opened; then, respectively, the iron mouth and the channel and accessories for conveying slag and iron are controlled or set, thereby serving uniform iron tapping on the one hand, and providing a physical separation mechanism for the smooth separation of slag and iron on the other hand; through the above-mentioned comprehensive setting, it is realized as a whole that molten iron is seen as soon as the iron mouth is opened, and there is no need to pre-discharge primary slag, while ensuring uniform iron tapping and easy separation of slag and iron, greatly reducing the consumption of a large amount of manpower and material resources during the furnace opening process.

Description

Technical Field

[0001] The invention belongs to the field of blast furnace smelting equipment and technology, and in particular relates to a method for controlling the first iron tapping when a large blast furnace is opened. Background Art

[0002] Blast furnace start-up is a complex system engineering, involving a wide range of aspects, especially large blast furnace start-up, which puts forward more stringent requirements on the normal operation of each system and the start-up plan. Among them, whether the first iron tapping after the blast furnace is started is normal is related to the success of the entire start-up process. In the early days, it was difficult to tap the first iron when the blast furnace was started. The main reason was that the calculation of iron tapping was not accurate enough. It was only through a rough estimate of the opening time of the iron mouth. After the iron mouth was opened, generally no molten iron was seen, and the initial slag had to be pre-discharged. Due to the low temperature of molten iron and poor fluidity of slag, the main ditch and slag ditch were easy to freeze, which caused great difficulties for the furnace front operation and the slag iron ditch system. At the same time, the discharged dry slag would also cause a lot of consumption and waste of manpower and material resources.

[0003] The invention application with application number: CN202010366038.6 discloses "a method for calculating the first iron-tapping time and a method for opening a blast furnace". The method includes the following steps: batching, determination of blast furnace distribution rules and basic matrix, calculation of furnace opening batching and determination of charging, determination of the first iron-tapping time, control of the smelting process after opening the furnace, control of the upper and lower operation systems during the smelting process and comprehensive smelting parameter control, and normal intensified smelting. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for controlling the first iron tapping of a large blast furnace, and the technical solution thereof is as follows:

[0005] A method for controlling the first iron tapping of a large blast furnace, characterized in that:

[0006] By controlling the time of the first tap hole opening, the tap hole can be opened and iron can be tapped immediately after the furnace is opened, thus forming the first tapping of iron in which molten iron is discharged first and then primary slag.

[0007] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0008] The control of the time of first taphole opening is achieved by monitoring the amount of molten iron generated in the furnace.

[0009] When the amount of molten iron generated in the furnace reaches the center line of the taphole, that moment is regarded as the moment when the taphole is opened for the first time.

[0010] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0011] By establishing monitoring of the amount of slag generated, a supplementary monitoring of the amount of molten iron generated in the furnace is established, and a safety monitoring mechanism is formed based on this supplementary monitoring;

[0012] If the amount of molten iron generated reaches the center line of the taphole, and the amount of slag generated accordingly exceeds the safe slag capacity, the time when the amount of slag generated reaches the safe slag capacity is taken as the time when the taphole is opened for the first time;

[0013] Otherwise, the time when the molten iron generated in the furnace reaches the center line position of the taphole is taken as the time when the taphole is opened for the first time.

[0014] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0015] The monitoring of whether the amount of molten iron generated in the furnace reaches the center line position of the taphole is achieved by monitoring the number of feeding times, as follows:

[0016] When the number of feeding times reaches the target number of feeding times, the accumulated air supply time corresponding to the corresponding amount of coke consumed is calculated, and at the same time, the air supply time required for the amount of slag generated to reach the safe slag holding capacity is calculated;

[0017] If the cumulative air supply time corresponding to the amount of coke consumed is less than or equal to the air supply time required for the amount of slag generated to reach the safe slag holding capacity, then the cumulative air supply time corresponding to the corresponding amount of coke consumed when the number of feeding times reaches the target number of feeding times shall be the time when the iron mouth is opened for the first time; otherwise, the air supply time required for the amount of slag generated to reach the safe slag holding capacity shall be the time when the iron mouth is opened for the first time.

[0018] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0019] The target number of feeding times is determined according to the following formula:

[0020] N=(V2×ρ1×K1-P1) / P2+(C1-V3×ρ3×K3) / C2

[0021] In the formula,

[0022] N: target number of feeding times;

[0023] V2: The volume of the dead iron layer area of ​​the blast furnace, unit: m 3 ;

[0024] ρ1: Density of molten iron in blast furnace, unit: t / m 3 ;

[0025] K1: iron content coefficient of blast furnace dead iron layer;

[0026] P1: The amount of molten iron generated by the pre-charged charge of the blast furnace, t;

[0027] P2: The production of molten iron after the blast furnace is ignited and loaded with normal materials, unit: t / ch.

[0028] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0029] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0030] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0031] ρ3: Coke bulk density, unit: t / m 3 ;

[0032] K3: Coke compression coefficient.

[0033] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0034] The cumulative air supply time corresponding to the corresponding number of feeding times is determined according to the following formula:

[0035] ∑t1=(N×C2×W) / B

[0036] Where:

[0037] ∑t1: The corresponding cumulative air supply time when the generated molten iron reaches the center line of the taphole, unit: min;

[0038] N: target number of feeding times;

[0039] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0040] W: air volume required to burn one ton of coke, unit: m 3 / t;

[0041] B: Weighted average air supply volume of blast furnace, unit: m 3 / min.

[0042] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0043] The amount of slag generated is determined according to the following formula,

[0044] Y=[(∑Bt) / W-C1+V3×ρ3×K3] / C2×S2+S1,

[0045] In the formula,

[0046] Y: the amount of slag currently generated, unit: t;

[0047] B: Actual air volume of blast furnace, unit: m 3 / min;

[0048] t: air supply time at current air volume, unit: min;

[0049] W: air volume required to burn one ton of coke, unit: m 3 / t;

[0050] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0051] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0052] ρ3: Coke bulk density, unit: t / m 3 ;

[0053] K3: coke compression coefficient;

[0054] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0055] S2: slag production after blast furnace ignition and normal charge, unit: t / ch;

[0056] S1: The amount of slag generated from the pre-charged charge in the blast furnace, unit: t.

[0057] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0058] The air supply time required when the amount of slag generated reaches the safe slag holding capacity is determined according to the following formula:

[0059] ∑t2={[(V1×ρ2×K2-S1)×C2] / S2-V3×ρ3×K3+C1}×W / B,

[0060] In the formula,

[0061] ∑t2: The corresponding cumulative air supply time when the amount of generated slag reaches the safe slag holding capacity, unit: min;

[0062] V1: The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, unit: m 3 ;

[0063] ρ2: blast furnace slag density, unit: t / m 3 ;

[0064] K2: blast furnace hearth iron content coefficient;

[0065] S1: slag generated from pre-charged blast furnace, unit: t;

[0066] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0067] S2: slag production after blast furnace ignition and normal charge, unit: t / ch;

[0068] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0069] ρ3: Coke bulk density, unit: t / m 3 ;

[0070] K3: coke compression coefficient;

[0071] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0072] W: air volume required for burning coke, unit: m 3 / t;

[0073] B: Weighted average air supply volume of blast furnace, unit: m 3 / min.

[0074] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0075] The volume V3 of the replacement furnace core coke in the formula is determined according to the following formula:

[0076] V3=(π / 3)×L1×(D1 / 2-L2) 2 +V1+V2,

[0077] In the formula,

[0078] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0079] L1: Height of coke in the furnace, unit: m;

[0080] D1: actual diameter of blast furnace hearth, unit: m;

[0081] L2: length of the air outlet circulation area, unit: m;

[0082] V1: The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, unit: m 3 ;

[0083] V2: The volume of the dead iron layer area of ​​the blast furnace, unit: m 3 .

[0084] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0085] The height L1 of the coke in the furnace core in the formula is determined according to the following formula:

[0086]

[0087] In the formula,

[0088] L1: Height of coke in the furnace, unit: m;

[0089] D1: actual diameter of blast furnace hearth, unit: m;

[0090] D2: equivalent diameter of coke, unit: m;

[0091] L2: The length of the air circulation area, unit: m.

[0092] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0093] By establishing adaptive control of the iron mouth in different working conditions, uniform iron tapping based on the iron mouth control is established.

[0094] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0095] It is also based on the respective settings of the three factors of the sand mouth aisle height, the liquid level difference between the slag discharge port and the iron ditch head, and the dam building height of the slag discharge port, which comprehensively forms a positive influence on the slag and iron separation.

[0096] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0097] The adaptation control of the iron mouth is as follows:

[0098] When the working condition is in the set time before ignition and air supply, the iron mouth is blocked and sealed based on mud bubbles;

[0099] When the working condition is in the set time after air supply, the iron mouth is unblocked and gas is sprayed outward from the iron mouth; until the initial slag is visually discharged, the iron mouth is blocked again.

[0100] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0101] The sand opening aisle height is set to 248-252mm;

[0102] The liquid level difference between the slag discharge port and the iron ditch head is set to 300mm-320mm;

[0103] The damming height of the slag discharge port is set to 50-70 mm;

[0104] A slag retaining plate is arranged at the front end of the sand opening to form an adaptation setting to the height of the sand opening aisle.

[0105] A method for controlling the first iron tapping at the start of a large blast furnace according to the present invention is characterized in that:

[0106] When the number of feeding times reaches the target number of feeding times, the corresponding cumulative air supply time is calculated.

[0107] Calculation of the amount of slag generated in real time,

[0108] Calculation of the air supply time required when the amount of slag generated reaches the safe slag holding capacity,

[0109] The comparison calculation between the corresponding accumulated air supply time when the feeding times reaches the target feeding times and the air supply time required when the generated slag volume reaches the slag safe holding volume is performed in the basic automatic control machine L1;

[0110] The number of times of adding materials and the above calculation results are all displayed through the human-computer interaction interface.

[0111] The invention discloses a method for controlling the first iron tapping of a large blast furnace, which is realized by establishing a two-level mechanism. In the first-level mechanism, the control of the first iron mouth opening time is first established to realize the iron tapping after the furnace is opened, so as to form the first iron tapping of first molten iron and then primary slag; then the iron mouth and the channel and accessories for conveying slag iron are respectively controlled or set, which serves for uniform iron tapping on the one hand and provides a physical separation mechanism for the smooth separation of slag iron on the other hand; through the above comprehensive setting, the iron mouth is opened to see molten iron, and there is no need to pre-discharge primary slag, while ensuring uniform iron tapping and easy separation of slag iron, which greatly reduces the consumption of a large amount of manpower and material resources in the furnace opening process. The establishment of the second-level mechanism serves the precise calculation of the iron mouth opening time in the first level, wherein the control of the iron mouth opening time is realized by establishing a precise calculation of the target number of feeding times, and the replacement amount of the core coke, which is crucial for blast furnace smelting, is taken into account in this calculation process; by setting up the monitoring of the amount of generated slag based on the safe slag capacity, a safety mechanism and guarantee are provided for precise control.

[0112] In summary, a method for controlling the first iron tapping of a large blast furnace according to the present invention not only controls and realizes normal iron tapping for the first time, but also realizes uniform iron tapping and easy separation of slag and iron, thus providing a guarantee for the successful start-up of the large blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] none DETAILED DESCRIPTION

[0114] Below, a method for controlling the first iron tapping during the opening of a large blast furnace according to the present invention is further described in detail according to a specific implementation method.

[0115] A method for controlling the first iron tapping of a large blast furnace when it is opened, which realizes iron tapping as soon as the furnace is opened by controlling the time of opening the first tap hole, and forms the first iron tapping in which molten iron is firstly discharged and primary slag is discharged later.

[0116] in,

[0117] The control of the time of first taphole opening is achieved by monitoring the amount of molten iron generated in the furnace.

[0118] When the amount of molten iron generated in the furnace reaches the center line of the taphole, that moment is regarded as the moment when the taphole is opened for the first time.

[0119] in,

[0120] By establishing monitoring of the amount of slag generated, a supplementary monitoring of the amount of molten iron generated in the furnace is established, and a safety monitoring mechanism is formed based on this supplementary monitoring;

[0121] If the amount of molten iron generated reaches the center line of the taphole, and the amount of slag generated accordingly exceeds the safe slag capacity, the time when the amount of slag generated reaches the safe slag capacity is taken as the time when the taphole is opened for the first time;

[0122] Otherwise, the time when the molten iron generated in the furnace reaches the center line position of the taphole is taken as the time when the taphole is opened for the first time.

[0123] in,

[0124] The monitoring of whether the amount of molten iron generated in the furnace reaches the center line position of the taphole is achieved by monitoring the number of feeding times, as follows:

[0125] When the number of feeding times reaches the target number of feeding times, the accumulated air supply time corresponding to the corresponding amount of coke consumed is calculated, and at the same time, the air supply time required for the amount of slag generated to reach the safe slag holding capacity is calculated;

[0126] If the cumulative air supply time corresponding to the amount of coke consumed is less than or equal to the air supply time required for the amount of slag generated to reach the safe slag holding capacity, then the cumulative air supply time corresponding to the corresponding amount of coke consumed when the number of feeding times reaches the target number of feeding times shall be the time when the iron mouth is opened for the first time; otherwise, the air supply time required for the amount of slag generated to reach the safe slag holding capacity shall be the time when the iron mouth is opened for the first time.

[0127] in,

[0128] The target number of feeding times is determined according to the following formula:

[0129] N=(V2×ρ1×K1-P1) / P2+(C1-V3×ρ3×K3) / C2

[0130] In the formula,

[0131] N: target number of feeding times;

[0132] V2: The volume of the dead iron layer area of ​​the blast furnace, unit: m 3 ;

[0133] ρ1: Density of molten iron in blast furnace, unit: t / m 3 ;

[0134] K1: iron content coefficient of blast furnace dead iron layer;

[0135] P1: The amount of molten iron generated by the pre-charged charge of the blast furnace, t;

[0136] P2: The production of molten iron after the blast furnace is ignited and loaded with normal materials, unit: t / ch.

[0137] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0138] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0139] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0140] ρ3: Coke bulk density, unit: t / m 3 ;

[0141] K3: Coke compression coefficient.

[0142] in,

[0143] The cumulative air supply time corresponding to the corresponding number of feeding times is determined according to the following formula:

[0144] ∑t1=(N×C2×W) / B

[0145] Where:

[0146] ∑t1: The corresponding cumulative air supply time when the generated molten iron reaches the center line of the taphole, unit: min;

[0147] N: target number of feeding times;

[0148] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0149] W: air volume required to burn one ton of coke, unit: m 3 / t;

[0150] B: Weighted average air supply volume of blast furnace, unit: m 3 / min.

[0151] in,

[0152] The amount of slag generated is determined according to the following formula,

[0153] Y=[(∑Bt) / W-C1+V3×ρ3×K3] / C2×S2+S1,

[0154] In the formula,

[0155] Y: the amount of slag currently generated, unit: t;

[0156] B: Weighted average air supply volume of blast furnace, unit: m 3 / min;

[0157] t: air supply time at current air volume, unit: min;

[0158] W: air volume required to burn one ton of coke, unit: m 3 / t;

[0159] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0160] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0161] ρ3: Coke bulk density, unit: t / m 3 ;

[0162] K3: coke compression coefficient;

[0163] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0164] S2: slag production after blast furnace ignition and normal charge, unit: t / ch;

[0165] S1: The amount of slag generated from the pre-charged charge in the blast furnace, unit: t.

[0166] in,

[0167] The air supply time required when the amount of slag generated reaches the safe slag holding capacity is determined according to the following formula:

[0168] ∑t2={[(V1×ρ2×K2-S1)×C2] / S2-V3×ρ3×K3+C1}×W / B,

[0169] In the formula,

[0170] ∑t2: The corresponding cumulative air supply time when the amount of generated slag reaches the safe slag holding capacity, unit: min;

[0171] V1: The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, unit: m 3 ;

[0172] ρ2: blast furnace slag density, unit: t / m 3 ;

[0173] K2: blast furnace hearth iron content coefficient;

[0174] S1: slag generated from pre-charged blast furnace, unit: t;

[0175] C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch;

[0176] S2: slag production after blast furnace ignition and normal charge, unit: t / ch;

[0177] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0178] ρ3: Coke bulk density, unit: t / m 3 ;

[0179] K3: coke compression coefficient;

[0180] C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t;

[0181] W: air volume required for burning coke, unit: m 3 / t;

[0182] B: Weighted average air supply volume of blast furnace, unit: m 3 / min.

[0183] in,

[0184] The volume V3 of the replacement furnace core coke in the formula is determined according to the following formula:

[0185] V3=(π / 3)×L1×(D1 / 2-L2) 2 +V1+V2,

[0186] In the formula,

[0187] V3: Volume of coke replaced in the furnace, unit: m 3 ;

[0188] L1: Height of coke in the furnace, unit: m;

[0189] D1: actual diameter of blast furnace hearth, unit: m;

[0190] L2: length of the air outlet circulation area, unit: m;

[0191] V1: The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, unit: m 3 ;

[0192] V2: The volume of the dead iron layer area of ​​the blast furnace, unit: m 3 .

[0193] in,

[0194] The height L1 of the coke in the furnace core in the formula is determined according to the following formula:

[0195]

[0196] In the formula,

[0197] L1: Height of coke in the furnace, unit: m;

[0198] D1: actual diameter of blast furnace hearth, unit: m;

[0199] D2: equivalent diameter of coke, unit: m;

[0200] L2: The length of the air circulation area, unit: m.

[0201] in,

[0202] By establishing adaptive control of the iron mouth in different working conditions, uniform iron tapping based on the iron mouth control is established.

[0203] in,

[0204] It is also based on the respective settings of the three factors of the sand mouth aisle height, the liquid level difference between the slag discharge port and the iron ditch head, and the dam building height of the slag discharge port, which comprehensively forms a positive influence on the slag and iron separation.

[0205] in,

[0206] The adaptation control of the iron mouth is as follows:

[0207] When the working condition is in the set time before ignition and air supply, the iron mouth is blocked and sealed based on mud bubbles;

[0208] When the working condition is in the set time after air supply, the iron mouth is unblocked and gas is sprayed outward from the iron mouth; until the initial slag is visually discharged, the iron mouth is blocked again.

[0209] in,

[0210] The sand opening aisle height is set to 248-252mm;

[0211] The liquid level difference between the slag discharge port and the iron ditch head is set to 300mm-320mm;

[0212] The damming height of the slag discharge port is set to 50-70 mm;

[0213] A slag retaining plate is arranged at the front end of the sand opening to form an adaptation setting to the height of the sand opening aisle.

[0214] in,

[0215] When the number of feeding times reaches the target number of feeding times, the corresponding cumulative air supply time is calculated.

[0216] Calculation of the amount of slag generated in real time,

[0217] Calculation of the air supply time required when the amount of slag generated reaches the safe slag holding capacity,

[0218] The comparison calculation between the corresponding accumulated air supply time when the feeding times reaches the target feeding times and the air supply time required when the generated slag volume reaches the slag safe holding volume is performed in the basic automatic control machine L1;

[0219] The number of times of adding materials and the above calculation results are all displayed through the human-computer interaction interface.

[0220] Working process, principle and implementation example

[0221] In order to accurately calculate the first tapping time after furnace opening and ensure smooth tapping after the tapping hole is opened,

[0222] The technical solution is based on the following technical principles:

[0223]

[0224] ∑Bt / W=(V2×ρ1×K1-P1)×C2 / P2+C1-V3×ρ3×K3.....(2)

[0225] (∑Bt / W-C1+V3×ρ3×K3) / C2×S2+S1≤V1×ρ2×K2............(3)

[0226] By calculating the above formulas (1) and (2) and verifying it with formula (3), the first iron tapping time can be calculated accurately and quickly:

[0227] T 出 =T+furnace opening time=∑t+furnace opening time

[0228] That is, after the blast furnace is ignited and air is supplied for a cumulative air supply time of T, the taphole can be opened to tap iron. At this time, it can be ensured that molten iron can be seen as soon as the taphole is opened, and the first batch of slag can be successfully flushed.

[0229] In the above formula (1), That is the height L1 of the coke in the furnace core;

[0230] The left side of the above formula (2) is the amount of coke consumed calculated by monitoring the air supply time; the right side is the amount of coke consumed based on the target number of charging times, which takes into account the replacement amount of core coke, which is crucial for blast furnace smelting. The left side of the inequality sign in the above formula (3) represents the amount of slag generated in real time, and the right side represents the safe slag capacity. The specific conversion process implied by the three formulas is as follows:

[0231] By establishing a monitoring of the number of times of adding materials and a monitoring of whether the amount of molten iron generated in the furnace reaches the center line position of the iron mouth, the iron mouth opening time is monitored, and by monitoring the amount of slag generated, a reinforced monitoring of the monitoring of the amount of molten iron generated in the furnace is established, and a safety monitoring mechanism is formed based on this reinforced monitoring; if the amount of molten iron generated reaches the center line position of the iron mouth, and the corresponding amount of slag generated exceeds the safe capacity of the slag, the moment when the amount of slag generated reaches the safe capacity of the slag is used as the moment when the iron mouth is first opened; otherwise, the moment corresponding to the amount of molten iron generated in the furnace reaching the center line position of the iron mouth is used as the moment when the iron mouth is first opened.

[0232] The meanings of the above parameters are as follows:

[0233] V1——The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, m 3 ;

[0234] V2——The volume of the dead iron layer area of ​​the blast furnace, m 3 ;

[0235] V3——The volume of coke in the replacement furnace, m 3 ;

[0236] P1——molten iron generated by blast furnace pre-charge, t;

[0237] S1——the amount of slag generated by the pre-charged charge of the blast furnace, t;

[0238] C1——Total amount of coke in the pre-charged charge of blast furnace, t;

[0239] P2——molten iron production after blast furnace ignition and normal charge, t / ch;

[0240] S2——the slag production after the blast furnace is ignited and loaded with normal materials, t / ch;

[0241] C2——coke batch loaded with normal material after blast furnace ignition, t / ch;

[0242] ρ1——Blast furnace molten iron density, t / m 3 ;

[0243] ρ2——Blast furnace slag density, t / m 3 ;

[0244] ρ3——coke bulk density, t / m 3 ;

[0245] D1——actual diameter of blast furnace hearth, m;

[0246] D2——equivalent diameter of coke, m;

[0247] L1——the height of coke in the furnace, m;

[0248] L2——the length of the air circulation area, m;

[0249] W——air volume required for burning coke, m 3 / t;

[0250] B——actual air supply volume of blast furnace, m 3 / min;

[0251] K1——iron content coefficient of blast furnace dead iron layer;

[0252] K2——iron content coefficient of blast furnace hearth;

[0253] K3——coke compression coefficient;

[0254] t——air supply time at current air volume, min;

[0255] T——Accumulative air supply time after blast furnace ignition, min;

[0256] T 出 ——The time when the first iron is produced from the furnace.

[0257] In addition to accurately calculating the first iron tapping time through the calculation method described above, it also includes making relevant preparations before tapping to ensure smooth tapping. The specific plan is as follows:

[0258] 30 minutes before ignition and air supply, first plug the iron mouth, fill the mud gun with mud, push it out and cut it flat, push the mud gun piston over the mud filling hole, and then operate the mud gun to press on the iron mouth without hitting the mud, and seal the iron mouth. 30 minutes after air supply, each iron mouth returns to the mud gun in turn, pokes the iron mouth with round steel, ignites the gas air spray, and opens the iron mouth connected to the gas discharge pipe in the furnace first. Block the iron mouth until the slag flows out of the iron mouth for about 2 meters, and hit the mud when blocking the mouth, with a mud amount of 100 kg. The bottom of the main ditch, iron ditch, and slag ditch are all paved with yellow sand; set a slag baffle at the front end of the sand mouth, and pad the slag baffle with yellow sand in front of the slag baffle. The height of the sand mouth aisle is 250mm; the liquid level difference between the slag discharge port and the iron ditch head is 300mm-320mm, and a dam with a height of 50-70mm is built at the slag discharge port.

[0259] In summary, the innovation of this technical solution lies in:

[0260] First, the volume of coke in the furnace core is calculated to determine the amount of coke burned during the blast furnace start-up process, and the time required is calculated based on the air consumption for burning the coke. This method is simple and effective, and has been verified many times during the start-up process of Baosteel's various bases.

[0261] Secondly, the present invention also improves the treatment of the iron mouth before ignition and air supply. Most of the original iron mouths are not sealed. The present invention first blocks the iron mouth eye, presses a mud gun on the iron mouth to seal it, and then withdraws the mud gun in turn 30 minutes after air supply, pokes the iron mouth with round steel, ignites the gas air spray, and ensures the uniformity of the iron mouth.

[0262] Thirdly, the present invention also optimizes and improves the preparation for iron tapping, including the height of the sand mouth passage, the liquid level difference between the slag discharge port and the iron ditch head, and the height of the dam at the slag discharge port.

[0263] Example

[0264] A blast furnace was recently opened. The tapping time after ignition was accurately calculated according to the present invention. It was found that after 21 hours of air supply, the cumulative air volume was 4.85 million m 3 After the furnace is opened, when the molten iron is loaded about 53 times, it is calculated that the molten iron can reach the center line of the iron mouth, as shown in the following table. At the same time, it is calculated that the slag has not reached the upper limit of the blast furnace slag storage capacity. Therefore, the iron mouth should be opened for tapping 21 hours after ignition and air supply.

[0265]

[0266] In the actual opening of this blast furnace, the first iron furnace was opened 21 hours after the air supply, and the actual air volume at the opening was 5100m 3 / min, with a cumulative air volume of approximately 4.84 million m 3 After the air was supplied, the charge had been loaded 53 times, which was basically consistent with the calculated data of the present invention. The preparation work before opening the taphole was also carried out completely in accordance with the present invention. Molten iron was seen as soon as the taphole of the first furnace was opened, slag was seen 46 minutes after opening, and the slag was successfully flushed. The slag and iron had good fluidity, which once again verified the accuracy of the present invention.

[0267] The invention discloses a method for controlling the first iron tapping of a large blast furnace, which is realized by establishing a two-level mechanism. In the first-level mechanism, the control of the first iron mouth opening time is first established to realize the iron tapping after the furnace is opened, and the first iron tapping is formed by first discharging molten iron and then discharging primary slag; then the iron mouth and the channel and accessories for conveying slag iron are respectively controlled or set, which serves for uniform iron tapping on the one hand, and provides a physical separation mechanism for the smooth separation of slag iron on the other hand; through the above comprehensive setting, the iron mouth is opened to see molten iron, and there is no need to pre-discharge primary slag, while ensuring uniform iron tapping and easy separation of slag iron, which greatly reduces the consumption of a large amount of manpower and material resources in the furnace opening process. The establishment of the second-level mechanism serves the precise calculation of the iron mouth opening time in the first level, wherein the control of the iron mouth opening time is realized by establishing a precise calculation of the amount of coke consumed, and the replacement amount of the core coke, which is crucial for blast furnace smelting, is taken into account in this calculation process; by setting up the monitoring of the amount of generated slag based on the safe slag capacity, a safety mechanism and guarantee are provided for precise control.

[0268] In summary, a method for controlling the first iron tapping of a large blast furnace according to the present invention not only controls and realizes normal iron tapping for the first time, but also realizes uniform iron tapping and easy separation of slag and iron, thus providing a guarantee for the successful start-up of the large blast furnace.

Claims

1. A method for controlling the first iron tapping of a large blast furnace, characterized in that: By controlling the time of the first tap hole opening, the tap hole can be opened immediately after the furnace is opened, forming the first tapping of iron with molten iron discharged first and primary slag discharged later. The control of the time of first taphole opening is achieved by monitoring the amount of molten iron generated in the furnace. When the amount of molten iron generated in the furnace reaches the center line of the taphole, this moment is regarded as the moment when the taphole is first opened; We also establish a monitoring system for the amount of slag produced and establish a reinforced monitoring system for the amount of molten iron produced in the furnace, thereby forming a safe monitoring mechanism. If the amount of molten iron generated reaches the center line of the taphole, and the amount of slag generated accordingly exceeds the safe slag capacity, the time when the amount of slag generated reaches the safe slag capacity is taken as the time when the taphole is opened for the first time; Otherwise, the time when the molten iron generated in the furnace reaches the center line of the taphole is taken as the time when the taphole is opened for the first time; The monitoring of whether the amount of molten iron generated in the furnace reaches the center line position of the taphole is achieved by monitoring the number of feeding times, as follows: When the number of feeding times reaches the target number of feeding times, the corresponding cumulative air supply time is calculated, and at the same time, the air supply time required for the generated slag volume to reach the slag safety capacity is calculated; If the corresponding cumulative air supply time is less than or equal to the air supply time required for the generated slag to reach the safe slag holding capacity, the corresponding cumulative air supply time when the target number of feedings is reached shall be the time for the first taphole opening; otherwise, the air supply time required for the generated slag to reach the safe slag holding capacity shall be the time for the first taphole opening. The target number of feeding times is determined according to the following formula: N=(V2×ρ1×K1-P1) / P2+(C1-V3×ρ3×K3) / C2 In the formula, N: target number of feeding times; V2: The volume of the dead iron layer area of ​​the blast furnace, unit: m 3 ; ρ1: Density of molten iron in blast furnace, unit: t / m 3 ; K1: iron content coefficient of blast furnace dead iron layer; P1: The amount of molten iron generated by the pre-charged charge of the blast furnace, t; P2: The production of hot metal after the blast furnace is ignited and loaded with normal materials, unit: t / ch; C2: coke batch loaded with normal material after blast furnace ignition, unit: t / ch; C1: Total amount of coke in the pre-charged charge of blast furnace, unit: t; V3: Volume of coke replaced in the furnace, unit: m 3 ; ρ3: Coke bulk density, unit: t / m 3 ; K3: Coke compression coefficient, The cumulative air supply time corresponding to the corresponding number of feeding times is determined according to the following formula: ∑t1=(N×C2×W) / B Where: ∑t1: The corresponding cumulative air supply time when the generated molten iron reaches the center line of the taphole, unit: min; W: air volume required to burn one ton of coke, unit: m 3 / t; B: Weighted average air supply volume of blast furnace, unit: m 3 / min, The amount of slag generated is determined according to the following formula, Y=[(∑Bt) / W-C1+V3×ρ3×K3] / C2×S2+S1, In the formula, Y: the amount of slag currently generated, unit: t; t: air supply time at current air volume, unit: min; S2: slag production after blast furnace ignition and normal charge, unit: t / ch; S1: slag generated from pre-charged blast furnace, unit: t, The air supply time required when the amount of slag generated reaches the safe slag holding capacity is determined according to the following formula: ∑t2={[(V1×ρ2×K2-S1)×C2] / S2-V3×ρ3×K3+C1}×W / B, where ∑t2: The corresponding cumulative air supply time when the amount of generated slag reaches the safe slag holding capacity, unit: min; V1: The volume from the center line of the blast furnace iron mouth to the lower edge of the tuyere, unit: m 3 ; ρ2: blast furnace slag density, unit: t / m 3 ; K2: blast furnace hearth iron capacity coefficient; The volume V3 of the replacement furnace core coke in the formula is determined according to the following formula: V3=(π / 3)×L1×(D1 / 2-L2) 2 +V1+V2, In the formula, V3: Volume of coke replaced in the furnace, unit: m 3 ; L1: Height of coke in the furnace, unit: m; D1: actual diameter of blast furnace hearth, unit: m; L2: length of the air circulation area, unit: m; The height L1 of the coke in the furnace core in the formula is determined according to the following formula: In the formula, D2: Equivalent diameter of coke, unit: m.

2. A method for controlling the first iron tapping of a large blast furnace according to claim 1, characterized in that: By establishing adaptive control of the iron mouth in different working conditions, uniform iron tapping based on the iron mouth control is established.

3. A method for controlling the first iron tapping of a large blast furnace according to claim 1, characterized in that: It is also based on the respective settings of the three factors of the sand mouth aisle height, the liquid level difference between the slag discharge port and the iron ditch head, and the dam building height of the slag discharge port, which comprehensively forms a positive influence on the slag and iron separation.

4. A method for controlling the first iron tapping of a large blast furnace according to claim 2, characterized in that: The adaptation control of the iron mouth is as follows: When the working condition is in the set time before ignition and air supply, the iron mouth is blocked and sealed with mud bubbles; When the working condition is in the set time after air supply, the iron mouth is unblocked and gas is sprayed outward from the iron mouth; until the initial slag is visually discharged, the iron mouth is blocked again.

5. A method for controlling the first iron tapping of a large blast furnace according to claim 3, characterized in that: The sand opening aisle height is set to 248-252mm; The liquid level difference between the slag discharge port and the iron ditch head is set to 300mm-320mm; The damming height of the slag discharge port is set to 50-70 mm; A slag retaining plate is arranged at the front end of the sand opening to form an adaptation setting to the height of the sand opening aisle.

6. A method for controlling the first iron tapping of a large blast furnace according to claim 1, characterized in that: When the number of feeding times reaches the target number of feeding times, the corresponding cumulative air supply time is calculated. Calculation of the amount of slag generated in real time, Calculation of the air supply time required when the amount of slag generated reaches the safe slag holding capacity, The comparison calculation between the corresponding accumulated air supply time when the feeding times reaches the target feeding times and the air supply time required when the generated slag volume reaches the slag safe holding volume is performed in the basic automatic control machine L1; The number of times of adding materials and the above calculation results are all displayed through the human-computer interaction interface.

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