CN113136467B - Efficient central focusing matrix setting method based on charge level iteration - Google Patents
Efficient central focusing matrix setting method based on charge level iteration Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 37
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- 238000004939 coking Methods 0.000 claims abstract description 21
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- C21B5/00—Making pig-iron in the blast furnace
- C21B5/008—Composition or distribution of the charge
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
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Abstract
The invention relates to the technical field of gear and inclination angle setting of coke and ore in a blast furnace top charging system, in particular to a high-efficiency central coking matrix setting method based on charge level iteration. The method specifically comprises the following steps: 1) setting the proportion of the ore-free area to the radius of the furnace throat to be 40% -45%, calculating the distance from the falling point of the innermost ring coke to the center of the furnace throat: 2) calculating the effective distance of the chute; 3) calculating the final velocity V of the charge after leaving the chute2(ii) a 4) Calculating the minimum focal Angle α from LminCharred min(ii) a 5) Calculating the inclination angle of each gear of the coke; 7) calculating the minimum inclination angle alpha of the oreMine min(ii) a 8) Calculating other tilting angles of the ore; 9) determining the number of circles of distribution of each ring position of coke: 10) determining the number of turns of distribution of each ring position of the ore; the collapse layer formed by coke in the material distribution process of the ore close to the ring position of the ore-free area is avoided, so that the air permeability and liquid permeability of the central material column are improved, and the central coke proportion can be greatly reduced to 15%. The utilization rate of coal gas is improved, and the fuel ratio is reduced.
Description
Technical Field
The invention relates to the technical field of gear and inclination angle setting of coke and ore in a blast furnace top charging system, in particular to a high-efficiency central coking matrix setting method based on charge level iteration.
Background
At present, a central coking material distribution method is widely adopted by domestic steel enterprises, but the specific setting of gears and inclination angles in a central coking matrix lacks a fine calculation method and effect analysis. Especially, how to control the rolling effect of the ore to the center, how to improve the material column skeleton effect of the center coke feeding so as to reduce the center coke feeding amount, and make more coke participate in the reduction of the iron ore is a problem which is concerned and needs to be solved urgently by each large iron and steel enterprise.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a high-efficiency central coking matrix setting method based on charge level iteration, which avoids a collapse layer formed by coke in the process of distributing ores close to the ring position of an ore-free area, controls the distance of the ores rolling from a falling point to the center within a stable area, ensures that no ore exists in the ore-free area of a central funnel, further improves the air permeability and liquid permeability of a central charge column, and can greatly reduce the central coking proportion to 15%. The utilization rate of coal gas is improved, and the fuel ratio is reduced.
In order to achieve the purpose, the invention adopts the following technical scheme:
according to the efficient central coking matrix setting method based on charge level iteration, through side slope theoretical calculation and charge level iterative fitting, the blast furnace adopting the matrix can greatly reduce the rolling of ore in an annular zone to a central coking area, further greatly improve the actual coal gas passing capacity of central coking, further greatly reduce the proportion of the central coking, and the number of turns of the ore is set to enable the blast furnace to easily form a w-shaped soft-capacity zone with better stability, and the method specifically comprises the following steps:
1) setting the proportion of the ore-free area to the radius of the furnace throat to be 40% -45%, calculating the distance from the falling point of the innermost ring coke to the center of the furnace throat:
in the formula: r isLarynxIs the furnace throat radius, m;
Lminthe distance m from the falling point of the innermost ring coke to the center of the furnace throat;
2) calculating the effective distance of the chute:
l＝L-e/tanα
in the formula: l is the effective length of the chute, m;
alpha is the chute inclination angle;
l is the chute length, m;
e is the chute tilting distance m;
3) calculating the final speed V of the furnace charge after leaving the chute2：
v1＝λv0
In the formula: v. of0The material flow speed before falling into the chute, m/s;
f is the actually measured flow of the furnace charge out of the throttling valve, m3/s；
S is the projected area of the throttle valve, m2；
ls is the length of the peripheral edge of the throttle valve, m;
d0m is the average particle size of the furnace burden;
v1the initial speed of the furnace burden after falling into the chute is m/s;
λ is the velocity loss coefficient;
w is the chute angular velocity, rad/s;
4) calculating the minimum focal Angle α from LminCharred min
When r is Lmin, the chute tilting angle is set as the minimum coke tilting angle alphaCharred min；
5) Calculating the inclination angle of each gear of coke:
the furnace wall is arranged to LminThe annular area of the furnace is equally divided into N-1 parts which are equal to the number of gears, and the radius of the falling point of the Nth gear is equal to the radius r of the furnace throatLarynxThat is, the maximum ring position of coke distribution, the drop point of which is required to be tangential to the furnace wall, the radius drop point of the Nth-1 st gear is calculated by the following formula:
according to the radius of each falling point, calculating the corresponding chute tilting angle, wherein the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minWhen the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minThe corresponding drop point radius evenly divides the ore platform area into N parts;
minimum inclination angle alpha of the cokeCharred minDividing the cross section area of the furnace throat into an ore platform area and an ore-free area by the coke falling point radius of the angle, wherein the area of the ore-free area accounts for 40-45% of the radius of the furnace throat; the falling point of the outermost ring inclination angle of the coke is tangent to the furnace wall, and each gear inclination angle of the coke divides the ore platform area into N areas with equal area.
6) Calculating the inner stacking angle and the outer stacking angle of each ring position of the coke:
internal stack angle theta1：
Outer bank angle θ:
coke: theta 73.12-1.97 alpha (alpha 18)
Sintering ore: theta 79.77-2.04 alpha (alpha >22)
In the formula: theta0Is a chargeNatural heap angle, °;
k is a correction coefficient;
h is different stockline depths m corresponding to different chute angles;
r is the furnace throat radius, m;
alpha is the chute inclination angle;
the coke inner stack angle and the coke C1 ring position outer stack angle of the coke C1 ring position and the coke C2 ring position are respectively calculated by the formula:
θinner C1、θInner C2And thetaOuter C1
7) Calculating the minimum inclination angle alpha of the oreMine min：
In the formula: l isminIs the coke innermost ring falling point pile tip C1Distance to the center of the furnace throat, m;
delta L is the horizontal distance between the ring position falling point of coke C2 and the ring position falling point of C1, m;
i.e. Δ L ═ Rc2-Lmin
Rk1After the determination, calculating the minimum inclination angle alpha of the ore by using the drop point calculation formula in the step 4Mine min；
And (3) outwards moving the alpha ore min with the minimum inclination angle of the ore to a certain degree relative to the alpha coke min, controlling the falling point to be outside the unstable region of the coke layer, and calculating the outwards moving distance by using the formula in the step (7) so as to reduce the rolling of the ore to the center and the collapse of the coke layer.
8) Calculating other tilting angles of the ore:
Rk2＝Rk1+λ×(Rc3-Rc2)
in the formula: rc (Rc)2Is coke C2Radius of point drop, m;
Rc3is coke C3The radius of the point where the point falls, m;
λ is a stacking experience parameter; the value range is 0.75-0.85
Rk2After determination, the method comprises the following steps4, calculating a second ring inclination angle alpha of the ore by using a calculation formula of a falling pointMine 2；
Lambda is obtained from the material surface stacking fitting result, and when the value range of the lambda is 0.75-0.85, K is2Stacking tip height and outer stacking angle of and K3The shape is the most flat;
9) determining the number of circles of distribution of each ring position of coke:
the outer ring N of the coke is blocked and each ring is distributed for 2 circles, the central coke adding proportion is controlled to be 15-25 percent, and the central coke adding falling point is set to be C0The number of the distribution turns is x, the central coking proportion is 15%, the coke N is blocked at the ring position, each ring of distribution turns is 2, x/(2N + x) is 0.15x is 0.353N to 0.667N, and the rest coke positions are 2 turns;
10) determining the number of circles of distribution of each ring position of ore:
to ensure K1Number of turns being 1, KN-1Number of turns being 3, KNNumber of turns being 2, K2The number of turns of other gears is less than or equal to 2, can be flexibly adjusted but is less than or equal to 3; the number of turns of ore distribution is set to be alphaMine minThe number of turns of the ore distribution of the outermost ring which is cut towards the furnace wall is 1 turn, and the number of turns of the ore distribution of the two rings close to the outermost ring is 3 turns, so that the thickness distribution of the ore bed is controlled, and a w-shaped soft capacity belt is formed.
Compared with the prior art, the invention has the beneficial effects that:
1. and a stable area concept is provided, and the rolling distance of the ore to the center is reduced through material surface fitting and stacking tip distance calculation optimization, so that the center coke-adding material column skeleton effect is improved. The central coke adding ratio can be reduced by 5-10%, and the fuel ratio can be reduced while improving the smooth running.
2. And the flatness of the ore platform is improved by calculating the inner and outer stacking angles. The ore inclination angle and the coke inclination angle are reasonably and accurately staggered, and the thickness of a mixed layer close to an ore platform at a non-ore area is reduced. Improve the coal gas passing performance of the coke window.
3. The coke inclination angle is set and divided more scientifically, the minimum inclination angle of the coke is set according to the area of the ore-free area, and the size of the ore-free area is accurately set. And the mining area is equally divided according to the equal area. The more even charge level is formed.
4. Radial ore load is inclined towards the center from the original whole body, and the design is thickened for a middle ore bed, so that a w-shaped soft capacity belt is formed. And the reasonable distribution of the two air flows at the center and the edge is promoted by optimizing the shape of the soft containing belt.
Saddle steel 2580m3The blast furnace was subjected to an industrial test of the distribution matrix setting method in 2020 from 9 to 12 months:
the first stage is as follows: the matrix of the pre-test stage is as follows:
| gear position | 5 | 4 | 3 | 2 | 1 | 0 |
| Inclination angle of coke | 39° | 36.5° | 34.1° | 32.3 | 30.3 | 12° |
| |
2 | 2 | 2 | 2 | 2 | 4 |
| Inclination angle of ore | 39° | 36.5° | 34.1° | 32.3° | 30.3° | 12° |
| |
2 | 2 | 2 | 2 | 2 |
And a second stage: the matrix of the test transition stage is as follows:
| gear position | 5 | 4 | 3 | 2 | 1 | 0 |
| Inclination angle of coke | 39° | 36.5° | 34.1° | 31.6° | 29.1° | 12° |
| |
2 | 2 | 2 | 2 | 2 | 3 |
| Inclination angle of ore | 39° | 36.5° | 34.1° | 32.3° | 30.3° | 12° |
| |
2 | 3 | 3 | 2 | 1 |
And a third stage: the final matrix calculated according to the method is:
| gear position | 5 | 4 | 3 | 2 | 1 | 0 |
| Inclination angle of coke | 39° | 36.5° | 34.1° | 31.6° | 29.1° | 12° |
| |
2 | 2 | 2 | 2 | 2 | 2 |
| Inclination angle of ore | 39° | 36.5° | 34.1° | 32.3° | 30.3° | 12° |
| |
2 | 3 | 3 | 2 | 1 |
The effect is produced: under the condition that the air quantity is not obviously increased, the daily average productivity is greatly improved, the daily average air quantity range difference is reduced, the smooth running stability is enhanced, the coal gas utilization rate is improved, and the comprehensive coke ratio is reduced by 10-15kg/t (see figure 6 for details); the computer of the first stage and the third stage fits the shape of the charge level (see fig. 4 and 5).
Drawings
FIG. 1 is a schematic diagram of the inside and outside diagonal of the present invention;
FIG. 2 is a schematic view of the toe distance and inside and outside toe angles of the present invention;
FIG. 3 is a comparison of inverted V and W soft bands of the present invention;
FIG. 4 is a saddle steel 5 blast furnace original matrix, computer charge level fitting shape;
FIG. 5 is a matrix calculated by the present invention for a saddle steel 5 blast furnace, and a computer charge level fitting shape;
FIG. 6 shows the experimental results of the setting method of the saddle steel 5 blast furnace high efficiency center focal length array.
Detailed Description
The invention discloses a high-efficiency central focusing matrix setting method based on charge level iteration. Those skilled in the art can modify the process parameters appropriately to achieve the desired results with reference to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.
A high-efficiency central focusing matrix setting method based on charge level iteration is characterized in that inner and outer pile angles of coke and ore with different drop point radiuses are calculated by utilizing drop point calculation software, and on the basis, a slope theory is combined to analyze collapse coefficients of a coke layer so as to study the influence of the inner pile angles and rolling distances formed by the ore on the coke layer at the different drop point radiuses. Determining a steady-state area where the innermost coke layer close to the center cannot cause collapse, calculating critical points of the steady-state area and the non-steady-state area, and controlling the falling point of the minimum ore corner of the ore to be beyond the critical points. Ensure that the ore does not roll down towards the centre. The cloth matrix calculation method realizes stable cloth, improves the permeability and liquid permeability of coke in the center of unit weight, and can further greatly reduce the ratio of the coke in the center.
Meanwhile, the proportion of the area of the furnace throat occupied by the non-ore region can be controlled more accurately through the calculation of the critical point, and the width of the ore platform can be controlled more accurately. The original mode of equally setting gear inclination angles according to the furnace throat sectional area 11 is changed into the mode of setting the proportion (40% -50%) of the ore-free area, and the radius of the ore-free area is set as the falling point radius of the innermost ring position of the coke. And dividing the annular section formed from the furnace wall to the radius of the innermost ring of the coke into N parts, wherein N is equal to the set gear number. The proportion of the dead zone is a parameter which can be accurately adjusted. And the calculation of the innermost ring of the ore enables the rolling distance of the ore stacking angle to be close to the critical point but less than the critical point, so that the width of the ore platform can be accurately determined along with the determination of the minimum focal angle and the minimum ore angle. The defect that the rolling effect of the ore is not considered in all the non-ore areas and the width of the ore platform in the past is overcome. The adjustment of the system is more accurate and controllable.
The specific calculation process and principle are as follows:
the method comprises the following steps: setting the ratio of the ore-free area to the furnace throat radius to be 40-45%, and calculating the innermost ring coke falling pointDistance L from the center of the furnace throatmin：
To obtain Lmin；
Step two: calculating the effective distance of the chute:
l＝L-e/tanα
l is the effective length of the chute, m; alpha is the chute inclination angle; w is the chute angular velocity, rad/s; l is the chute length, m; e is the chute tilting distance m;
step three: calculating the final speed V of the furnace charge after leaving the chute2：
v0M/s is the material flow velocity before falling into the chute
F is the actually measured flow of the furnace charge out of the throttling valve, m3S; s is the projected area of the throttle valve, m2(ii) a ls is the length of the perimeter edge of the throttle valve, m; d0 is the average particle size of the burden, m; v. of1The initial speed of the furnace burden after falling into the chute is m/s;
v1＝λv0
λ is the velocity loss coefficient;
step four: according to LminCalculating the minimum focal angle, αCharred min
Step five: calculating the inclination angle of each gear of the coke:
according to LminThe furnace wall is arranged to LminThe annular area of the gear is equally divided into N-1 gears with the same numberThe radius of the falling point of the Nth gear (N is 5 or 6) is equal to the radius r of the furnace throatLarynxI.e. the maximum ring position of the coke distribution, the drop point of which is required to be tangential to the furnace wall. The radius drop point of the N-1 st gear can be calculated by the following formula:
according to the radius of each falling point, calculating the corresponding chute tilting angle, wherein the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minI.e. when the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minAnd the corresponding drop point radius can evenly divide the ore platform area into N parts.
Therefore, for a distribution matrix with N baffles (the value of N ranges from 4 to 7), the coke tilt angle distribution is as follows:
the significance of this step is: the method for equally dividing the ore area changes the traditional method for equally dividing the furnace throat into n parts, so that the theoretical width of the ore platform area is fixed, the equal-area distribution of the annular distribution of the ore area is realized, the equal-height distribution of the ore is more facilitated, and the more reasonable ore platform charge level shape is formed.
Step six: calculating the inner stacking angle and the outer stacking angle of each ring position of the coke:
and calculating the tilting angle matrix of each ring position of the coke by reverse extrapolation through the calculation of the coke falling point radius. (the calculation method is a formula of step three)
Calculating the inner and outer opposite angles of each ring position angle of coke:
internal pile angle (theta) of charge level1(degree) and out-of-plane stockpiling angle (theta, degree) (see fig. 1) are influenced by the type of the charge and the depth of different stocklines corresponding to different chute angles, and under the condition of determining the type of the charge, the following formula can be used for solvingSolution:
internal stack angle theta1：
Outer bank angle θ: coke: theta 73.12-1.97 alpha (alpha >18) sinter: theta 79.77-2.04 alpha (alpha >22)
In the formula, theta0Is the natural stacking angle of furnace burden; k is a correction coefficient; h is different stockline depths m corresponding to different chute angles; r is the furnace throat radius, m; alpha is the chute inclination angle.
And calculating the inner pile angle and the outer pile angle of the pile tip formed by the inclination angles of the coke ring positions through the formula.
And (3) computational simulation and analysis of the charge level shape:
for multi-ring distribution, when the distribution system is determined, the distribution volume Vr of a certain ring is determined, namely Vr is Vtotal Pr/p, Vtotal is the total volume of a batch of coke or ore, m3(ii) a p is the total number of rings and circles of the cloth; pr is the number of turns and circles of the cloth distributed by the ring position with the radius of r; for a ring of furnace charge, the contour line equation can be calculated according to the size of the inner and outer pile angles, and the upper contour line equation is set as f1(x), and the lower contour line equation is set as f2(x)
The volume of the furnace burden at different drop points is calculated in a computer iteration mode, the shape of the burden surface of the burden distribution of the blast furnace is obtained through fitting, and the calculation flow of the burden distribution of the blast furnace is shown in figure 2. The volume of the burden distributed into the blast furnace is the volume of a rotating body formed by new and old burden surfaces, and the calculation formula is as follows:
in the formula: v is the volume of the furnace charge, m 3; x is the radial distance between the furnace burden falling point and the furnace throat center, m; (ii) a f1(x) is the new charge level surface at radius x, m; f2(x) is the old charge surface at radius x, m charge surface stability analysis: see fig. 2, iterative feed surface volume based on the assumed same tilt angle for coke and ore ring positionsCalculating, pile tip KNTo K1The position of (2) will be relatively fixed after 3-10 batches. The internal and external pile angles of the pile tip at each point are fixed, and the function change is actually the height of the pile tip position.
However, the way that coke and ore adopt the same tilting angle has obvious problems:
the ore rolling distance is large: minimum mine angle K1The distance of the ore rolling to the center is 1.7m or more in the experimental test, and the K is the same as the coke pile tip1The rolling distance of the points is long, resulting in a pile tip K under the same ore volume1Relative height of dot, relatively K2、K3、K4、K5Lower, thereby reducing the height of the rolloff line. This is also why this type of distribution requires at least more than 20% central coking.
② the thickness of the coke mixing layer is increased: when the ore particle size is smaller than that of coke, a coke-ore mixture layer is inevitably generated, but when the tilt angle is small, the coke mixture increases, and the air permeability deteriorates.
The rolling distance of the ore to the center is greatly influenced by a material line, the coke pushing effect is more obvious, and the large coke tends to the center. The potential for coke collapse increases according to the slope stabilization theory.
Fourthly, the material surface forms an integral downward slope and a stacking tip K2And K1The external heap angle of (A) is too large, reaching 11 DEG and 16 DEG respectively, and K4And K3The points are only 2 ° and 6 °, the charge level is poor. Underutilization of space below the roll-off line
Therefore, the charge level formed by the same tilting angle of the ore and the coke has a larger optimization space.
Therefore, the calculation of the minimum dip angle of the ore:
according to the slope stability theory and the coke and ore bed mixed theory formula: Δ Lc ═ 3.49 × 10-4(ek+ep) -0.316 where Δ Lc is the mixed layer thickness, m; ek is the ore collision energy, J; ep is the ore falling potential energy, J; when the falling point K of the minimum inclination angle of the ore1Falling outside the point o in fig. 2, the rate of coke collapse is greatly reduced.So that the minimum dip drop point of the ore is controlled to be outside the O point, and K1Dot sum K2The height of the pile tip of the dot cannot be higher than the roll-off line. The amount of ore rolling down to the center and the amount of coke slumping can be greatly reduced.
The solving method of the coordinates of the O point is as follows: point O to coke innermost ring pile tip C1OH by coke stack tip C1And C2The relative height of the pile tip C and the distance L between the pile tips of the two points are influenced, in the actual cloth, by the pile tip C1The coke rolling distance to the center is larger at the part, so the actual stack tip C in the initial charge level of iteration1The height of the point is inevitably smaller than C2The height of the pile tip of the dot, resulting in a decrease in OH.
Therefore the theoretical maximum OH of OHmax
The formula can be used:
calculating where L is the coke heap tip C1And a pile tip C2M; thetaInner C2Is a pile tip C2Inner bank angle of dots, °; theta.theta.Outer C1Is the coke heap tip C1The external stacking angle of points, °;
step seven: minimum inclination angle alpha of oreMine minThe calculation of (2):
when the minimum inclination angle alpha of the oreMine minThe falling point being the stacking tip K1Distance R between point and furnace throat centerk1＝Lmin+OHmaxIn this case, the falling point of the coke layer can be ensured to be outside the unstable region of the coke layer.
Namely, it is
LminIs the coke innermost ring falling point pile tip C1Distance to the center of the furnace throat, m;
Rk1after the determination, the minimum inclination angle alpha of the ore is calculated through a drop point calculation formulaMine min
Step eight: calculation of other tilting angles of ores
The inclination angles of the outermost ring of the ore and the Nth ring position are the same as those of the coke. The falling point position and the coke falling point position are tangent to the furnace wall;
the tilting angle from the N-1 th retaining ring position to the 3 rd retaining ring position of the ore is also the same as that of the coke;
the dip angle of the No. 1 baffle ring position of the ore is the minimum dip angle alpha of the oreMine min；
Falling point radius R of inclination angle of No. 2 baffle ring position of orek2The calculation formula is as follows:
Rk2＝Rk1+λ×(Rc3-Rc2)；
wherein R isc2Is the coke C2 point drop radius, m; rc3 is the coke C3 point-fall radius, m; lambda is a stacking experience parameter, and is obtained from a material surface stacking fitting result, when the value range is 0.75-0.85, K2Stacking tip height and outer stacking angle of3The shape is the flattest.
Rk2After the determination, calculating a second ring inclination angle alpha of the ore by using the drop point calculation formula in the step 4Mine 2；
The chute inclination angles of other ore gears are the same as the chute inclination angle of coke, so that for a distribution matrix with N gears, (N value range is 4-7), the complete inclination angle distribution of coke and ore is as follows:
step nine: determining the number of circles of distribution of each ring position of coke:
the calculation principle is as follows: the outer ring N of the coke is blocked for distributing 2 circles of materials per ring, the central coking proportion is controlled to be 15%, the number of the distributing circles with the central coking, namely the falling point of C0 is set to be x circles, the central coking proportion is enabled to be 15%, the ring position is blocked for the coke N, and the distributing number of each ring is 2 circles. When 5 gears are set, x/(2N + x) is 0.15, N is 5, and x is 1.76x and takes an integer of 2 turns.
Step ten: determining the number of circles of distribution of each ring position of ore:
the distribution of the number of circles of the ore distribution ring needs to consider the full utilization of the height of the roll-off line, so that k in figure 14And k3The height of the stacking tip is increased to form a trapezoidal material of oreThe surface changes the shape of the traditional ore material surface which is a big inclined surface inclined downwards. While making full use of the space below the ore falling line, the k is3And K4The height of the stacking tip is increased, and the ore bed is thickened. The position of the lower soft capacity belt is moved downwards to form a w-shaped soft capacity belt, the shape of the soft capacity belt is changed by lifting the height of the pile tip, and the gas flow can move obliquely upwards to the edge in secondary distribution because the gas flow moves transversely through the coke window in the soft capacity belt. More beneficial to form two stable and abundant air flows. Thereby optimizing forward motion.
But k is4And k3The height of the pile tip cannot be too high, and the height of the roll-off line is reduced after the pile tip is too high through iterative calculation. Through the iterative simulation and the blast furnace practice, the number of turns of K4 ore and K3 ore is K2The effect is best when the number of turns of the ore is 1.5 times.
Therefore, the setting method of the number of turns of distribution of each ring position of the ore comprises the following steps:
K1number of turns being 1, K2To KN-3Number of turns being 2, KN-2And KN-1Number of turns being 3, KNThe number of turns is 2, i.e., the ore number of turns is allocated to O233221 when six gears are set, and the ore number of turns is allocated to O23321 when five gears are set. The ore lap number is distributed as O233221 when six gears are set, or O232221 the ore lap number is distributed as O23321 or O23221 when five gears are set; when a four-ring gear is set to be O2321; when the seven-ring gear is set to O2332221 or O2333221.
Through the steps, the distribution matrix angle and the number of turns of each ring of the blast furnace are calculated and determined.
[ examples ] A method for producing a compound
Taking a saddle steel five-blast furnace as an example:
the method comprises the following steps: because the average grain size of the sintered ore used by the five blast furnaces is smaller, about 22mm, 45 percent is selected in a non-ore area, and the calculation is carried out
Step two: according to LminCalculating the minimum focal angle, alphaCharred min
When the radius of the falling point is 2.75m, the tilting angle alphaCharred min＝29.1°
Step three: inclination angles of coke gears are as follows:
the outermost ring-down point of the coke is cut along the furnace wall, and the area of the ore platform is equally divided into 4 parts. The coke is divided into 5 gears which are respectively alpha5、α4、α3、α2、αCharred minAccording to
And a drop point calculation formula:
calculating the radius of a drop point of 5 gears and the corresponding tilting angle respectively as follows:
step four: calculating the coke inside and outside stacking angles at each gear coke tilting angle:
according to the formula:
internal stack angle theta1：
Outer bank angle θ:
coke: theta 73.12-1.97 alpha (alpha 18)
Sintering ore: theta 79.77-2.04 alpha (alpha >22)
| Gear position | Gear inclination angle ° | Out-of-coke stack angle ° | In-focus heap angle ° | Out-of-mine heap angle ° | In-mine heap angle ° | Width m of ring position |
| α5 | 39.0 | 14.55 | 0.21 | 19.55 | ||
| α4 | 36.5 | 2.31 | 15.04 | 5.31 | 19.84 | 0.29 |
| α3 | 34.1 | 6.97 | 15.49 | 10.21 | 20.10 | 0.32 |
| α2 | 31.6 | 11.82 | 15.92 | 15.31 | 20.36 | 0.35 |
| αCharred min | 29.1 | 16.67 | 16.32 | 20.41 | 20.60 | 0.39 |
Step six: calculating the minimum inclination angle alpha of the oreMine min
According to the formula
Calculating the radius of a drop point of the minimum inclination angle of the ore as follows:
according to the formula
Calculating the minimum inclination angle alpha ore min of 30.3 °
Step seven: calculating the inclination angles of ores in other gears:
the dip angle for ore 2 nd gear is calculated as: rk2＝Rk1+λ×(Rc3-Rc2)＝2.94+0.75*0.36＝3.21m,
The inclination angle alpha 2 of 2 nd position of ore is 32.3 °
The inclination angle alpha 2 of 3 rd position of ore is 34.1 °
The inclination angle alpha 2 of the 4 th position of the ore is 36.5 DEG
The inclination angle alpha 2 of 5 th gear of ore is 39.0 °
Step eight: determining the number of turns of each gear of coke and ore:
setting the central coke proportion as 15%, wherein the coke turn number is C222222; the ore is set as O23321 according to the theory;
the final material distribution matrix of the blast furnace calculated according to the steps is as follows:
| gear position | 5 | 4 | 3 | 2 | 1 | 0 |
| Coke rake angle | 39° | 36.5° | 34.1° | 31.6° | 29.1° | 12° |
| |
2 | 2 | 2 | 2 | 2 | 2 |
| Inclination angle of ore | 39° | 36.5° | 34.1° | 32.3° | 30.3° | 12° |
| |
2 | 3 | 3 | 2 | 1 |
The matrix is obtained by calculation according to the method, and the matrix is brought into a computer to be operated and fitted to obtain the shape of the cloth charge level. As shown in fig. 5
Compared with the original five-blast furnace material distribution matrix which does not adopt the method of the patent
| Gear position | 5 | 4 | 3 | 2 | 1 | 0 |
| Coke rake angle | 39° | 36.5° | 34.1° | 32.3 | 30.3 | 12° |
| |
2 | 2 | 2 | 2 | 2 | 4 |
| Inclination angle of ore | 39° | 36.5° | 34.1° | 32.3° | 30.3° | 12° |
| |
2 | 2 | 2 | 2 | 2 |
The shape of the cloth surface obtained by fitting after the calculation is carried out by the computer is shown in figure 4
Two charge level shape contrast characteristics:
1. by adopting the charge level of the new method, the central coke amount is reduced, but the central coke amount is not overlapped with the ore layer, and the air permeability of the central coke column is greatly improved. Further, the central coke amount decreases and the coke pile height decreases, but the central coke skeleton and louver capacity increase conversely.
2. The material surface of the new method is reduced, the ore rolling is reduced, and the actually fitted ore-free area is greatly increased. The method conforms to the theory of central coking, and the central ventilation capability does not depend on how much coke is present but does not depend on the concept of ore.
3. The shape of the ore material surface is changed from an inclined plane shape into a shape with a high middle part and two low sides, which is beneficial to the formation of a w-shaped soft-capacitance belt.
As shown in figures 1-6, the method combines slope theory and quantitative mathematical analysis through multiple iterative calculation and practical comparison of the shape of the charge level. The influence of the ore on the collapse effect of the coke layer is calculated and analyzed, the concept of the stable interval of the coke layer is put forward for the first time, and the minimum ore coke falling point of the ore is controlled within the stable interval, so that the rolling effect of the ore to the center is reduced, and the effect efficiency of the center coke is improved. Meanwhile, the size of the drop point of the ore-free area is accurately controlled, so that the occupation ratio of the ore-free area becomes a parameter which can be accurately adjusted. The angular position difference between the gears is set more scientifically by using a method of equally dividing the area of the ore platform. And then, searching the optimal ore angle difference and ring number distribution which are most beneficial to forming the w-shaped soft melting zone by using iterative simulation. The invention combines the theory of no-mining area, the theory of side slope, the experimental result of the rolling effect of ore, the influence of the thickness of the ore bed on the shape of the soft melting zone and the iterative charge level simulation together from a new angle, thereby realizing scientific setting of the inclination angle of the central angle and the number of the gear rings.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.
Claims (2)
1. The efficient central coking matrix setting method based on charge level iteration is characterized in that through side slope theoretical calculation and charge level iterative fitting, a blast furnace adopting the matrix can greatly reduce the rolling of ore in an annular zone to a central coking area, further greatly improve the actual coal gas passing capacity of central coking, further greatly reduce the proportion of the central coking, and set the number of turns of the ore to enable the blast furnace to easily form a w-shaped soft smelting zone with better stability, and specifically comprises the following steps:
1) setting the proportion of the ore-free area to the radius of the furnace throat to be 40% -45%, calculating the distance from the falling point of the innermost ring coke to the center of the furnace throat:
in the formula: r isLarynxIs the furnace throat radius, m;
Lminthe distance m from the falling point of the innermost ring coke to the center of the furnace throat;
2) calculating the effective distance of the chute:
l＝L-e/tanα
in the formula: l is the effective length of the chute, m;
alpha is the chute dip angle, DEG;
l is the chute length, m;
e is the chute tilting distance m;
3) calculating the final velocity V of the charge after leaving the chute2：
v1＝λv0
In the formula: v. of0The material flow speed before falling into the chute is m/s;
f is the actually measured flow of the furnace charge out of the throttling valve, m3/s；
S is the projected area of the throttle valve, m2；
ls is the length of the perimeter edge of the throttle valve, m;
d0m is the average particle size of the furnace burden;
v1the initial speed of the furnace burden after falling into the chute is m/s;
λ is the velocity loss coefficient;
w is the chute angular velocity, rad/s;
4) calculating the minimum focal Angle α from LminCharred min：
When r is Lmin, the chute tilting angle is set as the minimum coke tilting angle alphaCharred min；
5) Calculating the inclination angle of each gear of the coke:
the furnace wall is arranged to LminThe annular area of the furnace is equally divided into N-1 parts which are equal to the number of gears, and the radius of the falling point of the Nth gear is equal to the radius r of the furnace throatLarynxThat is, the maximum ring position of coke distribution, the drop point of which is required to be tangent to the furnace wall, the radius drop point of the Nth-1 st gear is calculated by the following formula:
according to the radius of each falling point, calculating the corresponding chute tilting angle, wherein the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minWhen the coke tilting angle is alphaN、αN-1、αN-2、αN-3…αCharred minThe corresponding drop point radius evenly divides the ore platform area into N parts;
6) calculating the inner stacking angle and the outer stacking angle of each ring position of the coke:
internal stack angle theta1：
Outer bank angle θ:
coke: theta 73.12-1.97 alpha (alpha 18)
Sintering ore: theta 79.77-2.04 alpha (alpha >22)
In the formula: theta0Is the natural stacking angle of furnace burden;
k is a correction coefficient;
h is different stockline depths m corresponding to different chute angles;
r is the furnace throat radius, m;
alpha is the chute inclination angle;
calculating the coke C by the above formula1Ring position and C2Annular coke internal stack angle and coke C1The ring position outer stack angle is respectively as follows: thetaInner C1、θInner C2And thetaOuter C1；
7) Calculating the minimum inclination angle alpha of the oreMine min：
In the formula: l isminIs the coke innermost ring falling point pile tip C1Distance to the center of the furnace throat, m;
delta L is the horizontal distance between the C2 ring position drop point and the C1 ring position drop point of the coke, m;
i.e. Δ L ═ Rc2-Lmin；
Rk1After the determination, calculating the minimum inclination angle alpha of the ore by using the drop point calculation formula in the step 4Mine min；
8) Calculating other tilting angles of the ore:
Rk2＝Rk1+λ×(Rc3-Rc2)
in the formula: rc (Rc)2Is coke C2The radius of the point where the point falls, m;
Rc3is coke C3The radius of the point where the point falls, m;
λ is a stacking empirical parameter; the value range is 0.75-0.85,
Rk2after the determination, calculating a second ring inclination angle alpha of the ore by using the drop point calculation formula in the step 4Mine 2；
The chute inclination angles of other ore gears are the same as the chute inclination angle of coke;
9) determining the number of circles of distribution of each ring position of coke:
the outer ring N of the coke is blocked and each ring is distributed for 2 circles, the central coke adding proportion is controlled to be 15 to 25 percent, and the central coke adding falling point is set to be C0The number of the distribution turns is x, the central coking proportion is 15%, the coke N is blocked at the ring position, each ring of distribution turns is 2, x/(2N + x) is 0.15, x is 0.353N-0.667N, and the rest coke positions are 2;
10) determining the number of circles of distribution of each ring position of ore:
K1number of turns being 1, KN-1Number of turns being 3, KNNumber of turns equal to 2, K2Less than or equal to 2, and the number of turns of other gears is less than or equal to 3.
2. The setting method of the efficient central focusing matrix based on the burden surface iteration as claimed in claim 1, wherein the step 10) further comprises setting the ore distribution turn number as alphaMine minThe number of turns of ore distribution of the outermost ring tangent to the furnace wall is 1, the number of turns of ore distribution of the outermost ring is 2, and the number of turns of ore distribution of the two rings close to the outermost ring is 3, so that the thickness distribution of an ore bed is controlled, and a w-shaped reflow zone is formed.
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