Method for judging working state of blast furnace by taking coke from tuyere

Abstract

The invention discloses a method for judging the working state of a blast furnace through tuyere coke taking. The method comprises the following steps that the length and groove intervals of a sampling gun are designed according to the furnace capacity; during damping down of the blast furnace, the sampling gun and the cover plate are inserted from the tuyere in the radial direction of the blast furnace, the cover plate on the sampling gun is pulled out, a mixture of coke, slag and iron in the furnace falls into the sampling gun, the sampling gun is pulled out immediately, the cover plate is added immediately, meanwhile, protective gas is introduced, and the hot mixture is cooled to the room temperature; taking out each section of sample from the sampling gun, separating coke, slag and iron in each section of sample, weighing, storing and marking; and after sampling, respectively screening and weighing each section of coke, calculating the mass percentage of each stage of coke, calculating and evaluating the size fraction of the coke, and calculating according to data to obtain corresponding blast furnace working parameters. The method is simple in equipment, convenient to operate and capable of directly determining the coke quality and accurately judging the state of the blast furnace so as to guide smooth production of the blast furnace.

Description

Technical Field

[0001] The invention belongs to the field of blast furnace ironmaking and can be used to judge the working state of the blast furnace and provide a basis for adjusting the operation of the blast furnace. Background Art

[0002] The evaluation of the working status of a blast furnace is not only a key link to ensure stable production and improve production efficiency, but also an important task related to the economic benefits, safety and equipment reliability of the enterprise. Only by using scientific evaluation methods to timely discover and solve problems can we ensure that the blast furnace continues to operate efficiently, safely and stably. As a fuel and ore reducing agent in blast furnace smelting, coke plays a more important role as the skeleton of the material column. With the continuous increase of the coal injection ratio of the blast furnace, the skeleton role of coke in the furnace becomes more and more important. Due to the size of the tuyere whirlpool zone of coke combustion, the deterioration of coke and the accumulation behavior of coke powder, they will have a significant impact on the descent of the charge and the permeability and liquid permeability of the material column. Therefore, understanding the properties of tuyere coke and mastering the properties of tuyere coke are very important for the stable operation of the blast furnace under high coal injection ratio conditions and for the evaluation of the working status of the blast furnace.

[0003] Sampling and analyzing the blast furnace tuyere is an effective means to study the tuyere circulation area and dead material column of the blast furnace. It can not only quantitatively understand the degree of coke degradation and directly evaluate the coke quality, but also understand the activity of the lower part of the blast furnace and the dead material column, and provide useful guidance for the control of furnace erosion. At present, the evaluation of blast furnace tuyere mainly relies on the subjective feeling of the staff. There is a lack of sufficient data support and detailed data collection and recording, and it is difficult to accurately analyze the working status of the blast furnace. Therefore, it is urgent to develop a method for taking coke from the tuyere to understand the properties of the tuyere coke and the properties of the tuyere coke, so as to judge the working status of the blast furnace and guide the production of the blast furnace. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for evaluating the working state of a blast furnace by taking coke from a tuyere. The method evaluates the particle size of the coke after taking the coke from the tuyere, thereby judging the working state of the blast furnace such as the slag iron retention rate, the uniformity of the circumferential direction of the furnace, and the activity of the furnace, so as to guide the smooth production of the blast furnace. The method has simple equipment and is easy to operate, and can directly determine the quality of coke and accurately evaluate the state of the blast furnace.

[0005] The present invention adopts the following technical scheme: a method for taking coke from a tuyere to evaluate the working state of a blast furnace, wherein sampling is performed using a sampling gun, wherein the sampling gun comprises a semi-enclosed side wall, a top wall fixedly connected to the top end of the side wall, and a bottom wall fixedly connected to the lower end of the side wall, and further comprises a cover plate slidingly and sealingly connected to the side wall, wherein the top wall, the side wall, the bottom wall and the cover plate together form a hollow cavity for storing samples, wherein a plurality of partitions are arranged in the hollow cavity and along the radial direction of the sampling gun, wherein the hollow cavity is divided into a plurality of independent hollow sub-cavities by the plurality of partitions, and wherein the plurality of hollow sub-cavities have pores interconnected with each other.

[0006] The following steps are also included:

[0007] Step 1: Each hollow sub-cavity of the sampling gun corresponds to a focus position, and the focus positions are sorted according to the serial numbers 1#, 2#, 3#, etc., and the serial numbers increase from near to far according to the distance from the air outlet;

[0008] Step 2: When the blast furnace is shut down, insert the sampling gun from the tuyere along the radial direction of the blast furnace, with the sampling length less than or equal to the radius of the furnace, and pull out the cover plate. The mixture of coke, slag and iron in each area of ​​the blast furnace falls into the corresponding hollow sub-cavity. Then pull out the sampling gun, immediately add the cover plate, and at the same time, introduce protective gas into several hollow sub-cavities to cool the hot mixture to room temperature;

[0009] Step 3: Take out each section of the sample from the sampling gun, separate the coke, slag and iron in each section of the sample, weigh and store them, mark them, and get the mass m of the i-th section of coke i and the mass m of the slag in the i-th section i渣铁 ;

[0010] Step 4: After sampling, screen and weigh each section of coke, calculate the mass percentage of each level of coke, evaluate the coke particle size, and calculate the corresponding blast furnace operating parameters based on the data.

[0011] Calculate the mass percentage of each level of coke using the following formula:

[0012]

[0013] Among them, P ij is the mass percentage of the j-grade coke in the i-th section, m j is the mass of the j-grade coke in the ith section, and M is the total mass of the ith section.

[0014] Furthermore, in step 1, the axial length of each hollow sub-cavity is 0.125, 0.25 or 0.5 m.

[0015] Furthermore, the protective gas in step 2 is nitrogen or argon.

[0016] Furthermore, the method for separating the coke, slag and iron in each section of the sample described in step 3 includes magnetic separation or gravity separation.

[0017] Furthermore, the diameters of the sieves used for the screening in step 4 are 40 mm, 25 mm, 10 mm, 5 mm and 3 mm, respectively.

[0018] Furthermore, the blast furnace operating parameters described in step 4 include the length of the tuyere raceway, the coke particle size in the tuyere raceway, the coke particle size in the dead coke pile, the slag iron retention rate and the floating height of the dead coke pile.

[0019] The length of the tuyere raceway is determined by the change in coke particle size;

[0020] The average particle size d of coke in each section is calculated in sequence. i平均 Calculate and determine whether it is less than 10mm; if the average particle size of this section is greater than or equal to 10mm, calculate and determine the average particle size of the next section until the average particle size is less than 10mm. The calculated tuyere raceway length D 回旋区 is the distance from the end point of the sampling grid to the furnace wall. The formula is as follows:

[0021] IF(d i平均 <10mm, D 回旋区 =D 空心子腔 ×i, i=i+1), i starts from 1.

[0022] where d i平均 =∑d i P i , d i is the mean of the upper and lower limits of each particle size range in the i-th segment, P i is the percentage of each particle size of coke in the i-th section to the total mass of coke; D 空心子腔 is the axial length of each hollow sub-cavity;

[0023] The formula for calculating the coke particle size in the tuyere raceway is as follows:

[0024] d 回旋区平均 =∑d i回旋区 P i回旋区

[0025] Among them, d 回旋区平均 is the coke particle size in the tuyere raceway, d i回旋区 is the mean value of the coke particle size in the tuyere raceway, P i回旋区 is the percentage of the coke in the i-th section of the raceway to the total mass of coke in the tuyere raceway;

[0026] The formula for calculating the particle size of coke in the dead coke pile is as follows:

[0027] d 死焦堆平均 =∑d i死焦堆 P i死焦堆

[0028] Among them, d 死焦堆平均 is the particle size of coke in the dead coke pile, d i死焦堆 is the mean value of the coke particle size in the i-th section of the dead coke pile, P i死焦堆 is the percentage of the coke in the i-th section of the dead coke pile to the total mass of the coke in the dead coke pile;

[0029] The formula for slag iron retention rate is as follows:

[0030]

[0031] Among them, R i is the mass percentage of slag iron in the i-th section, m i渣铁 is the mass of slag iron in the i-th section, M i is the sum of the mass of slag and coke in the i-th section;

[0032] Actual floating height of dead coke pile h c Calculated by the following formula:

[0033] h c =λH s -λa(κ+1)

[0034] Where:

[0035] H s is the height of the slag liquid surface from the taphole, in meters;

[0036] κ is the slag-iron depth ratio, satisfying κ=γρ i / ρ s ;γ is the slag ratio,;ρ i and ρ s are the densities of molten iron and slag, respectively, in kg / m 3 ;

[0037] λ is a constant related to the blast furnace condition, satisfying ρ c is the true density of coke kg / m 3 ;

[0038] a is data related to blast furnace design parameters and actual operation data, calculated as follows:

[0039]

[0040] ρ m is the average density of the column, in kg / m 3 ,satisfy ρ o and ρ c are the true densities of ore and coke, respectively, in kg / m 3 ;m o and m c are the mass of ore and coke consumed per ton of iron, respectively, and ε is the porosity of the charge;

[0041] g is the acceleration due to gravity;

[0042] ΔV is the volume of the block band, satisfying ΔV=VV H -V T -N×V RW ,; V is the effective volume of the blast furnace; V HV is the volume of the dead coke pile in the furnace above the taphole, H =A×h H ;h H is the distance from the iron mouth to the center line of the tuyere; A is the cross-sectional area of ​​the furnace, A=πD 2 / 4; D is the furnace diameter; V T is the volume of the furnace throat void, V T =πd T 2 h T / 4; where d T is the furnace throat diameter, h T V is the material line depth; RW is the volume of a single raceway, V RW =πd RW 3 / 6,d RW is the depth of the raceway; N is the number of tuyere;

[0043] ΔV, V, V H , A and V T The unit is m 3 ;h H , D, d T 、h T and d RW The unit of is m;

[0044] ε d is the porosity of the dead coke pile;

[0045] P is the gas buoyancy, in N;

[0046] f is the wall friction, in N;

[0047] h is the designed dead iron layer depth, in meters.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] 1. At present, the evaluation of the working state of the blast furnace mainly relies on the subjective feeling of the staff, lacks sufficient data support and detailed data collection and recording, and it is difficult to accurately analyze the working state of the blast furnace. The method of the present invention evaluates the particle size of the coke after taking out the tuyere coke, thereby judging the blast furnace working state such as slag iron retention rate, uniformity of the circumferential direction of the hearth, and hearth activity, so as to guide the smooth production of the blast furnace.

[0050] 2. After taking the coke through the tuyere, the coke and slag in each section of the sample are separated, and the slag retention rate can be calculated. The coke in each section is screened and weighed respectively, and the average particle size of each section is calculated. On this basis, the length of the raceway, the coke particle size in the raceway, the coke particle size of the dead coke pile and the floating height of the dead coke pile can be calculated in turn according to the formula. According to the above parameters, combined with the commonly used hearth activity evaluation method, the furnace bottom center temperature (TD), furnace bottom / hearth side wall (A=TD / TC), and hearth cleanliness index (DCI) are obtained to discuss the hearth activity of the blast furnace. By discussing the activity of the blast furnace hearth, it is possible to guide the ore distribution, control the distribution of coal gas flow, formulate the blast furnace thermal system, and do a good job in the management of raw materials and fuel entering the furnace, so as to achieve the purpose of stable and smooth operation of the blast furnace.

[0051] 3. A method for evaluating the working condition of a blast furnace by taking coke out of the tuyere, wherein the particle size of the coke is evaluated after the coke is taken out of the tuyere, thereby judging the working conditions of the blast furnace such as the slag iron retention rate, the uniformity of the circumferential direction of the hearth, and the activity of the hearth. The method has simple equipment and is easy to operate. It can directly determine the quality of coke and accurately evaluate the state of the blast furnace, thereby guiding the smooth production of the blast furnace. DETAILED DESCRIPTION

[0052] A method for evaluating the working state of a blast furnace by taking coke from a tuyere, wherein sampling is performed using a sampling gun, wherein the sampling gun comprises a semi-enclosed side wall, a top wall fixedly connected to the top end of the side wall, and a bottom wall fixedly connected to the lower end of the side wall, and further comprises a cover plate slidably and sealingly connected to the side wall, wherein the top wall, the side wall, the bottom wall and the cover plate together form a hollow cavity for storing samples, wherein a plurality of partitions are arranged in the hollow cavity and along the radial direction of the sampling gun, wherein the hollow cavity is divided into a plurality of independent hollow sub-cavities by the plurality of partitions, and wherein the plurality of hollow sub-cavities are provided with pores interconnected with each other.

[0053] The following steps are involved:

[0054] Step 1: Each hollow sub-cavity of the sampling gun corresponds to a focusing position, and the focusing positions are sorted according to the serial numbers 1#, 2#, 3#..., and the serial numbers increase in sequence from near to far according to the distance from the air outlet.

[0055] Step 2: When the blast furnace is shut down, insert the sampling gun radially from the tuyere to the blast furnace, with the sampling length less than or equal to the furnace radius, pull out the cover plate, and the mixture of coke, slag and iron in various areas of the blast furnace falls into the corresponding hollow sub-cavities. Then pull out the sampling gun, add the cover plate immediately, and introduce protective gas into several hollow sub-cavities to cool the hot mixture to room temperature. After inserting to a certain distance, the sampling length is less than or equal to the furnace radius, pull out the cover plate, and the mixture of coke, slag and iron in important areas such as the whirlpool area, the bird's nest area and the dead material pile falls into the sampling gun. Then pull out the sampling gun, add the cover plate immediately, and introduce protective gas to cool the hot mixture to room temperature.

[0056] Step 3: Take out each section of the sample from the sampling gun, separate the coke, slag and iron in each section of the sample, weigh and store them, mark them, and get the mass m of the i-th section of coke i and the mass m of the slag in the i-th section i渣铁 Step 4: After sampling, screen and weigh each section of coke, calculate the mass percentage of each level of coke, evaluate the coke particle size, and calculate the corresponding blast furnace operating parameters based on the data.

[0057] The formula for calculating the mass percentage of coke at each level is as follows:

[0058]

[0059] Among them, P ij is the mass percentage of the j-grade coke in the i-th section, m j is the mass of the j-grade coke in the i-th section, and M is the total mass of the i-th section (the sum of the masses of all coke grades).

[0060] Specifically, the sampling gun described in step 1 is a slot type sampling gun, and the axial length of each hollow sub-cavity is 0.125, 0.25 or 0.5 m, which needs to be determined according to the capacity and diameter of the blast furnace.

[0061] Specifically, the sampling gun described in step 1 has a cooling water system structure in which a cooling water chamber is provided on the outer wall of the sampling gun, and a partition is designed inside the chamber to improve the cooling effect, so that the outer side is effectively cooled. Before using the sampling gun, start the cooling water system and adjust the valve to supply water at an appropriate flow rate; during use, regularly monitor the temperature of the sampling gun to ensure that it is within a safe range; regularly check the working status of the cooling water system, such as the water pump, valve, pipe and connection parts, to ensure its normal flow.

[0062] Specifically, the protective gas in step 2 is nitrogen or argon.

[0063] Specifically, the method for separating the coke, slag and iron in each section of the sample described in step 3 includes magnetic separation or gravity separation.

[0064] Specifically, the diameters of the sieves used for the screening in step 4 are 40 mm, 25 mm, 10 mm, 5 mm and 3 mm, respectively.

[0065] Specifically, the blast furnace operating parameters described in step 4 include the length of the tuyere raceway, the coke particle size in the tuyere raceway, the coke particle size in the dead coke pile, the slag iron retention rate and the floating height of the dead coke pile.

[0066] The length of the tuyere raceway is determined by the change in coke particle size;

[0067] According to the serial number (the coke taking position is sorted by serial number 1#, 2#, 3#..., and the serial number increases from near to far from the tuyere), the average particle size d of coke in each section is calculated in turn. i平均 Calculate and determine whether it is less than 10mm; if the average particle size of the current segment is greater than or equal to 10mm, calculate and determine the average particle size of the next segment until a segment with an average particle size less than 10mm is found, and calculate the length D of the tuyere raceway 回旋区 is the distance from the end point of the sampling grid to the furnace wall, and the formula is as follows:

[0068] IF(d i平均 <10mm, D 回旋区 =D 空心子腔 ×i, i=i+1), i starts from 1.

[0069] where d i平均 =∑d i P i , d i is the mean of the upper and lower limits of each particle size range in the i-th segment, P i is the percentage of each particle size of coke in the i-th section to the total mass of coke; D 空心子腔 is the axial length of each hollow sub-cavity.

[0070] The formula for calculating the coke particle size in the tuyere raceway is as follows:

[0071] d 回旋区平均 =∑d i回旋区 P i回旋区

[0072] Among them, d 回旋区平均 is the coke particle size in the tuyere raceway, d i回旋区 is the mean value of the coke particle size in the tuyere raceway, P i回旋区 is the percentage of the coke in the ith section of the tuyere raceway to the total mass of coke in the tuyere raceway;

[0073] The formula for calculating the particle size of coke in the dead coke pile is as follows:

[0074] d 死焦堆平均 =∑d i死焦堆 P i死焦堆

[0075] Among them, d 死焦堆平均 is the particle size of coke in the dead coke pile, d i死焦堆 is the mean value of the coke particle size in the i-th section of the dead coke pile, P i死焦堆 is the percentage of the coke in the i-th section of the dead coke pile to the total mass of the coke in the dead coke pile;

[0076] The formula for slag iron retention rate is as follows:

[0077]

[0078] Among them, R i is the mass percentage of slag iron in the i-th section, m i渣铁 is the mass of slag iron in the i-th section, M i is the sum of the mass of slag and coke in the i-th section;

[0079] Actual floating height of dead coke pile h c Calculated by the following formula:

[0080] h c =λH s -λa(κ+1)

[0081] Where:

[0082] H s is the height of the slag liquid surface from the taphole, in meters;

[0083] κ is the slag-iron depth ratio, satisfying κ=γρ i / ρ s ;γ is the slag ratio, kg / kg; ρ i and ρ s are the densities of molten iron and slag, kg / m 3 ;

[0084] λ is a constant related to the blast furnace condition, satisfying ρ c is the true density of coke kg / m 3 ;

[0085] a is data related to blast furnace design parameters and actual operation data, calculated as follows:

[0086]

[0087] ρ m is the average density of the column, in kg / m 3 ,satisfy ρ o and ρ c are the true densities of ore and coke, respectively, in kg / m 3 ;m o and m c are the amount of ore and coke consumed per ton of iron, respectively, where m o =1000 / T(Fe), unit is kg; T(Fe) is the ore grade; ε is the porosity of the charge;

[0088] g is the acceleration due to gravity, g = 9.81 m / s 2 ;

[0089] ΔV is the volume of the block band, satisfying ΔV=VV H-V T -N×V RW ,; V is the effective volume of the blast furnace; V H V is the volume of the dead coke pile in the furnace above the taphole, H =A×h H ;h H is the distance from the iron mouth to the center line of the tuyere; A is the cross-sectional area of ​​the furnace, A=πD 2 / 4; D is the furnace diameter; V T is the volume of the furnace throat void, V T =πd T 2 h T / 4; where d T is the furnace throat diameter, h T V is the material line depth; RW is the volume of a single raceway, V RW =πd RW 3 / 6,d RW is the depth of the raceway; N is the number of tuyere; ΔV, V, V H , A and V T The unit is m 3 ;h H , D, d T 、h T and d RW The unit is m.

[0090] ε d is the porosity of the dead coke pile;

[0091] P is the gas buoyancy, in N;

[0092] f is the wall friction, in N;

[0093] h is the designed dead iron layer depth, in meters.

[0094] Example 1: The tuyere coking and calculation were carried out for three blast furnaces with a capacity of more than 5,000 cubic meters. A slot-type sampling gun with a cover plate was used, which had its own circulating water. The sampling gun was 10 meters long and 8 meters effective. The sampling gun was designed with a 0.5-meter interval and was divided into 16 sections by welded metal partitions. The coking positions were sorted according to the serial numbers 1#, 2#, 3#, etc., and the distance from the tuyere became farther and farther.

[0095] When the blast furnace is shut down, the sampling gun together with the cover plate is inserted radially from the tuyere along the blast furnace. After being inserted to 8m, the cover plate on the sampling gun is pulled out, and the mixture of coke, slag and iron in important areas such as the furnace bosh, whirlpool area, bird's nest area and dead material pile falls into the sampling gun. The sampling gun is then pulled out and the cover plate is immediately added. At the same time, nitrogen protective gas is introduced to cool the hot mixture to room temperature.

[0096] Each section of the sample is taken out from the sampling gun, and the coke, slag and iron in each section of the sample are separated by magnetic separation and gravity separation, and then weighed.

[0097] After sampling, each section of coke is screened and weighed, the mass percentage of each level of coke is calculated, the coke particle size is evaluated, and the length of the tuyere whirlpool zone, the coke particle size of the tuyere whirlpool zone, the coke particle size of the dead coke pile, the slag iron retention rate and the floating height of the dead coke pile are calculated based on the data. As shown in Table 1:

[0098] Table 1

[0099]

[0100] Through the analysis of coke extraction at the tuyere, it can be seen that the length of the tuyere whirlpool zone of furnace C is basically between 1.5-1.75m, while the length of the tuyere whirlpool zone of furnaces A and B is 2.5m and above. From the overall analysis, the particle size of coke at the tuyere of blast furnace C is significantly lower than that of blast furnace A, especially the particle size of coke in blast furnace C falls to less than 10mm from 1 meter away from the furnace wall, while the coke in blast furnace A can be maintained at 5 meters away at that time. At the same time, through the calculation results of the floating height of dead coke pile, it can be seen that the floating height of dead coke pile in furnaces A and B is greater than that of furnace C, and the floating height of dead coke pile in furnace C fluctuates greatly, which also shows that the activity of the furnace hearth of furnaces A and B is better than that of furnace C.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for judging the working state of a blast furnace by taking coke from a tuyere, characterized in that: Sampling is performed using a sampling gun, the sampling gun comprising a semi-enclosed side wall, a top wall fixedly connected to the top end of the side wall and a bottom wall fixedly connected to the lower end of the side wall, and also comprising a cover plate slidably and sealingly connected to the side wall, the top wall, the side wall, the bottom wall and the cover plate together form a hollow cavity for storing samples, a plurality of partitions are arranged in the hollow cavity and along the radial direction of the sampling gun, the hollow cavity is divided into a plurality of independent hollow sub-cavities by the plurality of partitions, and the plurality of hollow sub-cavities have mutually connected air holes; The following steps are also included: Step 1: Each hollow sub-cavity of the sampling gun corresponds to a focus position, and the focus positions are sorted according to the serial numbers 1#, 2#, 3#, etc., and the serial numbers increase from near to far according to the distance from the air outlet; Step 2: When the blast furnace is shut down, insert the sampling gun from the tuyere along the radial direction of the blast furnace, with the sampling length less than or equal to the radius of the furnace, and pull out the cover plate. The mixture of coke, slag and iron in each area of ​​the blast furnace falls into the corresponding hollow sub-cavity. Then pull out the sampling gun, immediately add the cover plate, and at the same time, introduce protective gas into several hollow sub-cavities to cool the hot mixture to room temperature; Step 3: Take out each section of the sample from the sampling gun, separate the coke, slag and iron in each section of the sample, weigh and store them, mark them, and get the mass m of the i-th section of coke i and the mass m of the slag in the i-th section i渣铁 ; Step 4: After sampling, each section of coke is screened and weighed, the mass percentage of each level of coke is calculated, the coke particle size is evaluated, and the corresponding blast furnace operating parameters are calculated based on the data; Calculate the mass percentage of each level of coke using the following formula: Among them, P ij is the mass percentage of the j-grade coke in the i-th section, m j is the mass of the j-grade coke in the ith section, and M is the total mass of the ith section.

2. A method for judging the working state of a blast furnace by taking coke from a tuyere as claimed in claim 1, characterized in that: The axial length of each hollow sub-cavity in step 1 is 0.125, 0.25 or 0.5 m.

3. A method for judging the working state of a blast furnace by taking coke from a tuyere as claimed in claim 1, characterized in that: The protective gas described in step 2 is nitrogen or argon.

4. A method for judging the working state of a blast furnace by taking coke from a tuyere as claimed in claim 1, characterized in that: The method for separating the coke, slag and iron in each section sample described in step 3 includes magnetic separation or gravity separation.

5. A method for judging the working state of a blast furnace by taking coke from a tuyere as claimed in claim 1, characterized in that: The diameters of the sieves used for the screening described in step 4 are 40 mm, 25 mm, 10 mm, 5 mm and 3 mm, respectively.

6. A method for evaluating the working state of a blast furnace by taking coke from a tuyere as claimed in claim 1, characterized in that: The blast furnace operating parameters described in step 4 include the length of the tuyere raceway, the coke particle size in the tuyere raceway, the coke particle size in the dead coke pile, the slag iron retention rate and the floating height of the dead coke pile; The length of the tuyere raceway is determined by the change in coke particle size; The average particle size d of coke in each section is calculated in sequence. i平均 Calculate and determine whether it is less than 10mm; If the average particle size of this section is greater than or equal to 10mm, the average particle size of the next section is calculated and judged until the average particle size is less than 10mm. The calculated tuyere raceway length D 回旋区 is the distance from the end point of the sampling grid to the furnace wall. The formula is as follows: IF(d i平均 <10mm, D 回旋区 =D 空心子腔 ×i, i=i+1), i starts from 1; where d i平均 =∑d i P i , d i is the mean of the upper and lower limits of each particle size range in the i-th segment, P i is the percentage of each particle size of coke in the i-th section to the total mass of coke; D 空心子腔 is the axial length of each hollow sub-cavity; The formula for calculating the coke particle size in the tuyere raceway is as follows: d 回旋区平均 =∑d i回旋区 P i回旋区 Among them, d 回旋区平均 is the coke particle size in the tuyere raceway, d i回旋区 is the mean value of the coke particle size in the tuyere raceway, P i回旋区 is the percentage of the coke in the i-th section of the raceway to the total mass of coke in the tuyere raceway; The formula for calculating the particle size of coke in the dead coke pile is as follows: d 死焦堆平均 =∑d i死焦堆 P i死焦堆 Among them, d 死焦堆平均 is the particle size of coke in the dead coke pile, d i死焦堆 is the mean value of the coke particle size in the i-th section of the dead coke pile, P i死焦堆 is the percentage of the coke in the i-th section of the dead coke pile to the total mass of the coke in the dead coke pile; The formula for slag iron retention rate is as follows: Among them, R i is the mass percentage of slag iron in the i-th section, m i渣铁 is the mass of slag iron in the i-th section, M i is the sum of the mass of slag and coke in the i-th section; Actual floating height of dead coke pile h c Calculated by the following formula: h c =λH s -la(k+1) Where: H s is the height of the slag liquid surface from the taphole, in meters; κ is the slag-iron depth ratio, satisfying κ=γρ i / ρ s ;γ is the slag ratio,;ρ i and ρ s are the densities of molten iron and slag, respectively, in kg / m 3 ; λ is a constant related to the blast furnace condition, satisfying ρ c is the true density of coke kg / m 3 ; a is data related to blast furnace design parameters and actual operation data, calculated as follows: ρ m is the average density of the column, in kg / m 3 ,satisfy ρ o and ρ c are the true densities of ore and coke, respectively, in kg / m 3 ;m o and m c are the mass of ore and coke consumed per ton of iron, respectively, and ε is the porosity of the charge; g is the acceleration due to gravity; ΔV is the volume of the block band, satisfying ΔV=VV H -V T -N×V RW ,; V is the effective volume of the blast furnace; V H V is the volume of the dead coke pile in the furnace above the taphole, H =A×h H ;h H is the distance from the iron mouth to the center line of the tuyere; A is the cross-sectional area of ​​the furnace, A=πD 2 / 4; D is the furnace diameter; V T is the volume of the furnace throat void, V T =πd T 2 h T / 4; where d T is the furnace throat diameter, h T V is the material line depth; RW is the volume of a single raceway, V RW =πd RW 3 / 6,d RW is the depth of the raceway; N is the number of tuyere; ΔV, V, V H , A and V T The unit is m 3 ;h H , D, d T 、h T and d RW The unit of is m; ε d is the porosity of the dead coke pile; P is the gas buoyancy, in N; f is the wall friction, in N; h is the designed dead iron layer depth, in meters.

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