JPS60184607A - Operating method of blast furnace - Google Patents

Abstract

PURPOSE:To prolong the life of the titled blast furnace by estimating easily the erosion and solidification layer lines of the furnace bottom with use of the boundary element method, grasping always the state of erosion and the distribution of the solidification layers at the furnace bottom, and controlling rapidly and exactly on the basis of such information. CONSTITUTION:The maximum temp. of the furnace bottom is detected by a temp. sensor 6 furnished to the furnace bottom refractory material. The heat transfer at the furnace bottom is analyzed from said detected value with the boundary element method by using an axisymmetric body wherein the vertical axis of the furnace is used as the symmetry axis 1, and the erosion shape of the furnace bottom refractory material 8 is estimated. After detecting said maximum temp., the temp. is detected when the furnace bottom temp. is lowered. The shape of the solidification layer of the melt formed on the furnace bottom refractory material 8 is estimated in the same way as above-mentioned on the basis of the detected temp. and said estimated solidification shape. Subsequently, the thickness and distribution of the shape is controlled by the selection of the operating conditions of the furnace on the basis of said shape to prevent the growth of erosion of the refractory material 8.

Description

[Detailed description of the invention]

Furnaces such as blast furnaces, electric furnaces, and glass melting furnaces that contain high-temperature molten material and promote reactions are collectively referred to as blast furnaces.1. . In this specification, we will discuss the development results for the improvement of refractories and the extension of furnace life, using blast furnaces as a representative example. A new blast furnace that enables stabilization of blast furnace operations such as tapping slag by controlling the thickness distribution of the solidified layer by accurately and quickly estimating the distribution situation and the speed of its growth and decline. This paper proposes a method for operating the system. (Back forging technology) In recent years, the increasing size of blast furnaces in pursuit of high productivity and the harsher 41ψ working conditions have accelerated the wear and tear of the 1 Tr 1 refractory at the bottom of the furnace, shortening the life of the blast furnace front. Therefore, in blast furnace operation in a situation of low economic growth, it is important to maintain stable operation, extend the life of the blast furnace, and reduce the unit price of pig iron. (Time, 1lLI point) In order to maintain stable operation of the blast furnace and extend its lifespan, first of all, during the operation of the blast furnace, the 1φ corrosion condition of the bottom refractory should be checked at all times, and the 1hole 1□11χ4 measure should be taken at the 6 places where the corrosion occurs. It is essential to take measures quickly and accurately. In addition, at the same time, I is derived from the liquid and repeatedly forms and disappears on the refractory eroded surface.
It is essential to constantly monitor the distribution of the coagulated layer mixed with other charges, and to aim for a constant density of the liquid for protecting refractories, as well as to control the coagulated layer thickness and layer thickness distribution. This is a rh fort assignment. In other words, in terms of protection of the refractory, it is desirable that the coagulated layer shown in [2] should grow over the entire Fψ corrosion surface of the bottom refractory, but it is too thick and cannot reach the level of iron tapping. - If a solidified layer grows at the hearth bottom, the furnace bottom tends to cool down and become a slag, which hinders the tapping work. In such a case, the flow path of hot metal slag becomes small and becomes 1llrffl.
The resistance increases and the amount of hot metal slag that can be discharged during slag washing decreases, and the molten metal tends to remain in the hearth, resulting in poor ventilation throughout the furnace and In order to achieve both stable tapping slag work and effective protection of the furnace bottom 1 refractory, it is necessary to establish a technology that can control the waxing and waning of furnace bottom solidification, and to achieve optimal solidification. It is necessary to operate the blast furnace with optimum concentration by keeping the layer thickness and distribution constant.Therefore, it goes without saying that the corrosion status of the refractory at the bottom of the furnace 1, as well as formation and disappearance on the corroded surface, is important. Repeated online monitoring of the solidified layer results in 11iJ.Here, the bottom 1 refractory gradually wears out after blast furnace firing, so the temperature values measured by the sensors at each part of the bottom gradually decrease by 1%. However, in the short term, depending on changes in the blast furnace operating conditions and how the liquid is used to protect the refractories, solidification will grow on large objects and the temperature measurement on the first shift will drop. The sensor at r to z shows a value of 1'& high light, and 71J!l at the time of r.
・Using a wild goose and a straight line, ・Determine the condition of one refractory in one building,
and sensor 1ilI1. 1) It is necessary to successively estimate the degree of solidification behavior that is better than the refractory erosion surface estimated at the time using the measured temperature value at the time when the temperature decreases. The thickness distribution of the coal solid layer that ebbs and flows on the 4 lines of the furnace 1ζ refractory and the corrosion surface of the 1 refractory, the Aiga 1 line (
Hereinafter, in order to estimate the "surrounding layer line of the dike", 13 thermocouples were placed at the bottom of the blast furnace.
・(This means that we have to carry out the yunen measurement of the part. (Conventional technology) Is there a need to determine the throat of the 1 meal 1 cost layer line at the bottom of the hearth?
Using the actually measured temperature detected during thermal cauterization of the r section, one method was used to calculate simple one-dimensional heat transfer, paralysis, and sometimes two-dimensional heat transfer. The estimation of the solid phase line at the t) corner of the bottom corner is based on the aF calculation to 1 shaku in the - dimension. The axis is j! i
Even if it is simplified as a 11-symmetric body (simply referred to as an ``axis-symmetric body''), two-dimensional heat transfer calculations are essential. The finite element method has generally been used for this two-dimensional heat transfer calculation, but this is a very time-consuming and tedious task. In general domain methods such as the finite element method and the finite difference method, in the case of an axis-symmetric term, as shown in No. 114, the axis of symmetry is set as 1, and the meridian cross section 2 at θ = 0 shown by diagonal lines is divided into elements, and each element is variable (temperature) to satisfy the heat conduction equation with
Determine. Therefore, to estimate the erosion line, first, as shown in Fig. 2,
11 Considering the meridian cross section 2 of the hearth bottom at the actual measurement position, 4
Assuming an eroded solidified layer line 5, the area of the meridian cross section 2 in FIG. 2 is divided into elements and the temperature of each part is calculated. Generally, the erosion solidification layer line 5 is iron-carbon based eutectic I blackness (
Since it is considered to coincide with a constant width line of approximately 1150°C, this temperature of 1150°C is applied to the boundary condition between erosion solidification line 1 and line 5, and the bottom cooling condition is applied to the curved boundary. give. The 21st section shows an example of the results obtained by this method, and gives each isotherm. Next, the 1i-1' calculated value at the position of blackness 6 placed buried in the furnace bottom and the actual measurement 1st shift are compared. The temperature range where there is a difference between them,
For example, if it is larger than lOoC, move the erosion C doubt solid 1-line 5 a little, divide the new calculation area 2 again, and repeat the operation described above. This process is repeated until the cut value and the measured value match within a certain temperature range at all the positions of the bottom Y blackness meter 6, and the carburized solidified layer line 5 is determined. According to this method, one eroded solidification layer line 5 can be determined by 8i from the actual measurement at a certain point in time of the hearth thermometer 6 (Engineer 1
It takes a huge amount of time (people) x (half a day) x (1 week). 4 Needless to say, for this one itch, I needed a konko calculator.
In addition, the data required to be input 10 times is unusually large, so a fairly large computer is essential. Furthermore, although it is not impossible to automatically move the erosion solidification +4 line 5 and input the division of internal elements, the algorithm to execute it will be a chess card, and 1σ times the temperature Ml-e position Unnecessary temperature paralysis inside the device also increases calculation costs. As described above, it takes a lot of time to estimate the eroded and solidified layer line 5 at the hearth bottom using conventional domain methods such as the finite element method.
Not only is it extremely difficult to quickly estimate the furnace bottom erosion situation and take prompt and accurate measures to protect the furnace bottom, but it is also difficult to constantly grasp the solidified layer thickness distribution and take timely measures to protect the refractory. However, it is impossible to optimally control the layer 11 distribution so that the tap slag operation is stable. Furthermore, since multiple blast furnaces are generally installed in a steelworks, it is necessary to constantly monitor the bottom conditions of each blast furnace and take measures to protect the furnace in a long-term 1υJ manner to stabilize operations. Furnace body management, such as immediate response in case of an abnormality, was effectively fFiJ capability. (Start of the idea) Under these circumstances, the inventor used the boundary element method, a numerical method that has begun to be actively researched, to solve a t-axis symmetric problem from a two-dimensional intercondylar to a one-dimensional quantity 1.・Focusing on the fact that it is converted to 1, that is, in the 31st section; It is sufficient to separate the intersection M) into elements, and add the boundary bond division curve that corresponds to heat conduction or glue thickness by λ1 for each element (i.e., line segment) by 14, and the 414th boundary bond method An example of the heat transfer calculation at the bottom of the hearth and each isotherm obtained by this method are shown below. As shown in Figure 4, only the boundary line 4 is divided into elements using the boundary W' skin method (however, the +iR lines of the bricks are different! e includes those boundaries 'fY lines), and a total of 4 Then, Tamema was able to carry the cannon on his shoulders and the internal temperature was also obtained.
2) can be reduced by IIJ. In the method outside the boundary, this is the inside of the head,! 41J Chi Furnace bottom brick 8 element 1 chest is used as a small piece, Furnace rH brick 8
It becomes possible to automate the estimation of the eroded solid layer line 5. Soak-I! 1: What is the process of lfG constant in coagulation layer line 5?
- It is the same as the finite element method described above, but by applying the element method, the internal element separation for each stop of the 11+:Ilu solid 1f4 line 5 becomes f・outside, and the internal The temperature is also the temperature of the bottom of the hearth,'? 'If you do it only with fik position of I6, unnecessary old itch will disappear altogether. This measure: 1 to 2 minutes by applying the law, ki 1
The solution for one case (the true erosion line: the 11th position in Figure 6 where the line goes after jiB; the 14th place W of the 714th place where the true line 1-line 2 goes back) can be obtained in calculation time, so the monarchy Needless to say, uniform furnace body management for all blast furnaces in a steelworks will improve the stability of the tap iron slag production and the ability to take action against irregularities such as a rise in furnace bottom temperature.
The blast furnace has reached Ra level! This can bring great benefits such as stabilizing the industry and extending the life of the blast furnace. (Purpose of the Invention) To summarize what has been said above, the purpose of this invention is to reduce the dimension of the heat transfer problem by one dimension by utilizing the element method, and to convert the interval term to axis pair 1 into one dimension. This brings us to the problem: ■ Since this can be easily automated by using this method to estimate the line of the eroded solidified layer at the bottom of the blast furnace, it is possible to stabilize blast furnace M operations such as tapping slag work by on-line management of the furnace body. The aim is to develop a method for improving the performance of mining furnaces, which can lead to increased production and extension of furnace life. (TllJ construction of the invention) This invention is a dyeing method for a blast furnace that includes the following -V steps when carrying out the 1f work while monitoring the furnace IJgi of the l'8' furnace. (a) By means of a plurality of temperature sensors disposed on the bottom refractory and/or on the outside of the bottom refractory,
Furnace 1 1. I! (b) Step of detecting the maximum and each time of (a), (c)
From the temperature in (b), a heat transfer 1 tube analysis is performed using the boundary element method as a 11Ql+ symmetric body with the longitudinal axis of the furnace being 11+ symmetrical, and predicts the erosion shape of the bottom refractory L( (d) Step of detecting the temperature when the hearth bottom temperature becomes low after the step (b); (e) The temperature of (d) and the + of the hearth bottom refractory predicted in (C). :Based on the i-prize shape, heat transfer analysis was performed using the boundary four-element method as an axisymmetric body with the vertical axis of the furnace as the axis of symmetry. The solidified layer shape of the molten material in the furnace is
7. Based on the shape, the thickness and distribution are controlled by selecting the furnace operating conditions including the bottom cooling conditions, and the erosion growth of the bottom refractory of (C) is controlled by: 1 stop process. Now, in F, we will apply the calculation σ principle of the field element method and its application 1 to find out the excellent condition of the refractories at the bottom of the blast furnace and 11] the distribution of hard solids 1- that grow and disappear in one step of the refractory. We will specifically describe the procedure for estimating the situation online and stabilizing the furnace body management and operation of multiple blast furnaces. By the way, the boundary element method has various names such as the boundary end division method, boundary integral equation method, singular point solution method, Green's function method, and marginal integral finite element method, but the In other words, we conserve the field support IJe kibun integral equation into an integral or rod equation on the boundary], and then discretize it and divide it into cluster elements using the n-value solution method called the finite tree method and the method of approximation. l
They are all the same in that they contain Zj, and here they include all of the il, ε field', and Gj. (Calculation principle) 1Ill between axially symmetrical bonds by tjχt'+'-' element method! For the formulation, discretization, and solution of (Teikiden Netsuma 1111:] Consider the axial designation area Ω (formulated in Figure 5 G, not shown in 2), and its boundary surface Wr (=7'l + 7'2 +ra) t
6 G, the domination of the IM between the potentials or the distance j (and the boundary
The case is expressed as follows. Governing equation: 211 (Σ) = (l Listen/song...
・(1) Here, u (poor) is the potential at point 4 in Ω, u(n) and q(,,:) are I', -F
−'s (potential at EH point and r4iu east, uo+
Qo indicates the established value, and ua and h are the ambient potential and (heat) transfer coefficient. Den/Buma: Yanghe potential U of the condyle is @I! :, ffl east q ha heat a, becomes east. ηThe c〃 or rod equation on the l-circumference for the problem under consideration is given by the following equation (3). 0(,1i)11(,4,)+norpU(:) ・q
” (,:,0.,:)a r-JJrq(:)・u
'(, :□, ni) + 1' = 13) Here, L, the core represents the arbitrary point on F, and G(0・)＾ψ1 is C (brother, ) when the boundary is smooth. = 0.5,
When the curve is not smooth, the threshold can be determined indirectly using the equipotential condition. Also, market function u* (,i,
, shiba], or uo (poor i, paucity) is expressed by the expression (
The following component equation (4) corresponding to 1) is satisfied, and store number i
It is called 1+'4. 2u° (grass 1. grass] + δ -4,) = 0...
...(4) Here, Xo and shiba represent the points in Ω, and δ (sho-X-0) is the delta function of Dir ac. 1 and q of equation (4) for a three-dimensional object
” (X, ,
2) -θu*(b, poor)/θn=(-1/4πR2)
(aR/,,,) --(0) Here, R-1~-~1
1, which represents the distance between the point where the load is applied and point 4 on the pond. (5), (6)4: Also holds true for points Li and L on i and r. In the l1II symmetry problem, both the potential and flux are constant regardless of the circumferential direction. Therefore, as shown in the 51st fork, equations (3), (5), and (6) are converted to a cylindrical coordinate system, and the equations are converted into a combination and a rescue value is determined. Here, as shown in Fig. 5, the points of θ-θ'=o corresponding to opinions, , : are respectively set as L and 4, and the outward unit normal at the point is set as -(
n□, n2. n, ). Since θ-〇, it becomes N soldiers 2-, -0, and the outward unit normal n at the point is expressed by 5 as follows. A f(ni, n2+ na) - (5 cos θ, n
(to □sj-mθ) Ni (7) Furthermore, since Ω is axially symmetric, generality is not lost even if we consider the element □(θ-0) instead of i. Therefore, as θ−0, equation (5),
When the normal conduction between R and R in (6) is expressed in a cylindrical coordinate system, it is as follows. R = Iσ - σ, 1 ~ ^^ - (r + r -zrr 'cos θ + (Z - Z')"
:]% ・(8) θR/an=(rr'CO8θ)n
1/R+(to z-z'/R-=(9) However, older brother-(r
+θ, 2), Mu (r/, 0, z'). Now u, q on the intersection line S of the plane of θ-0 including two axes and F
Let the pupils of each be i, and since they are axially symmetric, we get the following. U (brother) - Une! , ], U(σ,) = u(ff,) to d
~1 ・(10) Therefore, the cylindrical coordinate system expression of equation (3) is given by the following equation (1). (j (,i4.)−u (,i,, )→−”ffF
. u(,i)-Ding(,j,,3)・l J l d7”
. 7/J7'oq(i)・Box i, H)・l J I d/
'. = (11) Here, /', u(σ, σ), q(σ
,,σ) are the cylindrical coordinate system expressions of C~1~ ~1~ 1', u'(a,,σ), and q'(a,,σ), respectively, and IJ+ is ~1~ ~1~. This is the Jacobian associated with employee transformation. (2) 1 miscellaneous damage and 1″ 1-cho method Equation (11) is the bond division method regarding the potential i of the intersection line SL of the γ-plane of θ-0 including Z・1111 and I゛, and l-C east 1 Just like the dimensional problem, if you divide S into C, you will get a formula for Aft, and if you subdivide this, the problem will be resolved once and for all. However, formula (11)
The pickling for u and q in the middle needs to be done on the surface I゛, [- of the first method, and it will be worth two tons. Now, we divide S into N boundary elements ζ, (tffi point i at 67 point j, +t is expressed as stone, and mutually.
Assume that u+Q in the element is expressed as follows using σ)3. U (older brother) - φ (kun), see, q (older brother no φ (older brother), demon)
・(12) Tor. Substituting equation (12) into equation (11), the following discretized algebraic equation is obtained. However, H1j=ff, .
・l J I dr. (14) G, = Jfr. jφ (original)・u@(E, prompt)・l J l d7'. (15). Here, for example, the boundary element (line segment) S shown in FIG.
5. r is expressed as follows by the coefficient of 1 of 2 and the variable conversion of 2. r-az +b=a@toz@t +azJ+l)-・・
・(16) Kokote, △zj=zj+□−2j, and a
, b represent the slope and intercept of the element S on the θ=0,000 plane. Using equation (16) to express the 9-fold SJ as a vector, r=
(a−ΔZ ・L+azJ I b )COεθ ・
'2 ~ j + (a *△Zj 11 t, +azJ+l) )s
inθ°↓+(△ZJ−t + Zj)・Tan ・・・・
......(17). Here, i and j are intermediate vectors in the directions of X, X, , Xli Hakata NN, , 1 2 8 . Using this, 5 in equation (9) and Ill in equation (11) can be expressed as follows. n = (△z, /1.) (i −ak) ・+・・
++...(1,8) ~ko, 1~ IJI-1, -(a, -△z, -t+az, +b)・-
-----(tO)J ] 3 tak, l is the length of element S, l - ((rJ+ t
-r] ) +J J J (△ZJ) There are two voices -C. JS (1/'1., - I J l "d rc-
I J l・(1θ・dt, formula % formula %) By performing the bond calculation, H4j and GIJ can be evaluated. z = rj'l in a constant plane,
,,%2. (Exactly the same equation (14)' for ζ,
(15) can be evaluated. Considering Equation (18) for all boundary nodes1, and noting that the value of U is defined on F0 and the value of q on F2 and F8-H, there are N unknowns and the algebra of the entire system is The equation becomes as follows. AX-F ・・＜20）
Here, A is a coefficient matrix, and X and F are column vectors containing only unknown node clears and only known stitches, respectively. 4 Just solve (20) for X. The potential at a given point X in Ω is 9 on the '1ε field
1 It can be calculated using the following equation using 1 node. The above calculation principle can be summarized as follows. ■ Create a sticky residual expression by combining the governing differential equation (Laplace equation) (1) of the steady heat conduction problem with the boundary condition (2). (Replace Yuko's residual expression with the boundary equation (a). ◎ Considering axial symmetry, #lf, L, and equation (3) can be transformed into the cylindrical coordinate system expression ( 11) is converted to 4-.@ In order to calculate the solution of equation (11) numerically, the area J or Ω
Boundary part F of (Fig. 5). When we divide into elements, we get Equation (18)
Each boundary f! divided x is used to plan the coefficient Jj + (yij (2〇+), (15)) of +Φ formula (13), which obtains the equation of; Appearance. . is expressed as a parameter by a vector (Equation (17)). (D If you have Ill (17), +”:, (14)
By converting (15) into a 2ri integral, we can obtain 1if ii@ by converting their 1-direction directly to the equation 1. ■ For each circumferential cable I".If we add 4 to Equation (18), we get
Mr. N's c! 1. Algebraic equation of N locks (2(1)
is completed, put it on the cape, and all r of 1 Kankai J2
a IG (and the heat flux is determined. bow t
し′) - to be done. Now, since the method of estimating the erosion line and the solidified layer line by the boundary element method is the same, after the temperature measured by the thermometer 6 temporarily rises and the corrosion of the refractory stops, the refractory protection liquid and operating conditions Erosion stops due to the change in liL 1-
The following describes the procedure for estimating the solidified layer line during the period in which the solidified layer is repeatedly formed and disappears, and the method for smoothing the tapping slag and operations by controlling the distribution. (]) Using a numerical calculation method based on the boundary element method, the heat transfer grinding (variables, beating temperature and heat flux) of an axisymmetric section are independent of the circumferential direction, and one meridional cross section is The equation is solved as , so it becomes a shoulder in two dimensions) is converted into the distance between bonds and time at the boundary of the meridian cross section of the axisymmetric area (the boundary can be expressed as a line segment, so it becomes a one-dimensional problem). (2) Since the bottom of the blast furnace (brick bond part 8) is considered to be an axially symmetrical body, as shown in Fig. ) is divided into minute boundary attributes (line segments) 9. (3) 4'f1. of coagulated layer line 5. IJ)) fj
1, and give a life of 50 side bright f device. Node 1 il on boundary element 9 of solidified layer line 5F
The boundary condition is 'Cchichi - the eutectic temperature of the carbon system 1151)
``Give C. (4) Node 1 (l) on node 9 of the other external world (for l, external cooling conditions (for heat removal or cooling,!
% transmission teacher). (5) At the node 1o on each field element 9, l#, temperature, heat flux, or heat conduction I! as a boundary condition. Which of the coefficients. Since one is given, 1ijl,, fi is lA'
f and 1 yesterday < can be done, all 1 subject world wing - 斡9] 2nd place j
The r crystal 1ρ and heat flux at point 1.11 will be determined (6) Using the AK degree and case 1 Kato at node 10 of each barrier g F, determined in this way, The value of 0'L of the thermometer 6 buried in the bottom of the furnace is determined by the temperature derived by the boundary element method.
Calculate @1 morning of IP't'C. (7) Pa 1゛l in 7 gl”3 place 11q):
If you take the ratio of ON and the actual value and add the preset conditions (for example, if the cold is all the temperature 1 ), then measure the initially assumed solidified layer line 5 with a thermometer l.
The true erosion line at 1i11 is assumed to be 14. (8) If the conditions are not satisfied, the solidified layer line 5
move automatically. (9) If [E
(3) ~ (7) +7) 7' Friend the process. (10) Until the pre-given conditions are satisfied (3) ~ (
7) process, the true Sof solid line 1
Determine 4. (11) True solidified layer line 1 from the measured value of 11 at a certain time
The calculation time required to determine Ifli of 1 is the initial estimate of 1.
It takes 1 to 2 minutes, but if you estimate it sequentially, it will be 10 to 3 ()
Since it is only a few seconds, the estimated solid line 1.4 of the furnace bottom 71 on the buried surface of the thermometer 6 is displayed online on the CRT and the operator is immediately informed. (12) This allows us to constantly grasp the distribution of the solidified layer in each part of the blast furnace bottom and realize more stable slag work.
It becomes possible to control the cost solid layer distribution at IB speed and accurately. (13) For example, for stable production and slag cultivation. It is imperative to ensure that the height of the roof is not higher than (+, fin) than the refractory level at the time of construction, and to protect the refractory as much as possible.
So that the 1st layer is the same as the 11ijJ fireworks 1ji change,
Controlled cooling of each part of the furnace 1, the bottom of the furnace, and the walls of the furnace bottom 11,111,
1 ton of hot air is blown in from the feather 1.
1. The decline in the distribution of the charge in the furnace is now being investigated. Kiza,・υyoｊ戊+41t
(14) It is estimated that the range in which the 11 depths of the coagulated layer are tightened to 4 degrees. If the tax is exempted, the cooling system should be adjusted so that they fit within the high range, and the hot air jet should be increased, and the charge in the blast furnace section (according to 5 + A adjustment; hot air furnace juice 4 fi
If the increase or decrease in the natural ratio is calculated as 11 - 7, then the temperature, then the interval based on the 1 value of 116 is the conventional method. rti-zo, 1
9 Warming refractory, cold) e11 conditions, heat; C solidified layer o) l! The depth and distribution are at the neck, and the H
With this method, it is difficult to quickly and accurately judge the impact of the coagulation layer distribution on the appearance and slag construction of beams, and the contribution to the protection of refractories.
[II] As mentioned for the first time, it took a lot of man-hours to successively estimate the distribution of the solidified layer, and it was almost impossible to estimate the actual condition. Not only is it possible to estimate erosion line 11, but it is also solidified! - Estimation of line 14 can be performed very easily and in a short time, and it can be done online, making it possible to monitor and control the solidified layer thickness and layer thickness distribution from time to time, resulting in stable blast furnace inspections. This advantageously results in a longer blast furnace life. FIG. 6 schematically shows an example of estimating the solidified layer line 14 at the bottom of a large blast furnace of 5,000 tons of pig iron of 8 grade, based on a certain lifetime value of the thermometer 6 buried in the bottom. A meridian cross section including the position of the thermometer 6 buried in the hearth bottom is considered, and its boundary 4 is divided into annium 9. The movement range of the solidified layer line 5 is set to the inner side of the furnace than the refractory erosion line 11 which was placed 11 at the previous point in time, and the w period IN of the solidified 1 phosphorus line 5 is given. Next, at the boundary node IO on the solidified layer line 5, 1150 'C'5-b f, -Jj furnace bottom brick 8 is set as the jet field condition.
The outer surface of (2-1) Give each cooling condition to the ascending node 10. Applying the eruption field curve 4ζ method, calculate the temperature and heat flow east at all boundary nodes 10, and the density at the position of l^A degree meter 6. Calculate. Do. l,!! degree aF 6 (7) Real 1ulJ iiA ToR
[<Ql rut Tokapme give error t, = solidify until the conditions are satisfied! - Move line 5 + ffJJ to A, and the result! The true solidified layer line 14, as shown in FIG. 6, is determined. (If the C force position of the V solid layer line 5 and the determined 1?t of the solidified layer line 14 are set, the calculation time required for IW constant will be 2 minutes, but when the nail' time BB is determined: If I5, the embankment solidification line 14 will be moved quickly to r with only a slight return, and the calculation time will be about 10 to 30 seconds. Average tapped iron F; 51) (l U t/da ,y (7
) Approximately 7 months after the above-mentioned blast furnace was fired, the 71 temperature indication value of the entire furnace bottom buried temperature Ht6 suddenly increased.
The corrosion line of the semi-no.Jl refractory at the time the maximum temperature reached 1 month was as shown in 11 in Figure 7. In response, cooling was strengthened at the bottom corners and the bottom surface of the furnace bottom, where erosion was expected to be particularly advanced, based on the warm line determined from time to time when the actual measurement values began to rise rapidly. Wind blower IT
In addition to taking short-term protective measures such as slightly reducing the amount of air, we simultaneously implemented long-term measures such as increasing the charging Ti-O2 and implementing periodic air breaks. Approximately one week after implementing this measure, the tendency of erosion of the refractories stopped.
The reading on the hearth bottom thermometer 6 became almost constant. A solidified layer of pig iron coke refractory fragments etc. begins to form on the refractory surface approximately 11 days after the logging is carried out.
The reading on the hearth bottom thermometer 6 began to gradually decrease. Therefore, from the 18th day after the treatment of leprosy, the amount of crushed waste was gradually increased, and the intensity of bottom cooling was gradually relaxed. Tl
The O2 charge l@ also decreased and the estimated coagulation I reached approximately 1 month later.
# Since the thickness exceeded 1.5 m over the entire bottom of the hearth, these liquid countermeasures were discontinued and the normal IIf/! work was performed. Blast furnace work such as tapping slag work was carried out every 1;n1 round.Next, approximately 11 months after firing, the blast furnace went into reduced production operation and the tap iron ratio was reduced from 1°8 to 1.5. About 5 days ago, the reading on the furnace bottom stability meter 6 began to drop as the taphole decreased, and it was considerably low for wheat.The estimated solidified layer line at point II; Figure 14
It was predicted that a large solidification layer would grow in the center of the furnace bottom, increasing the resistance to passage of hot metal and slag at the furnace bottom. Here, 1 iL from 11 hours after the hearth temperature started to decrease! The number of tap slags produced by tapping slag operations per liter began to decline, and the frequency of tapping slags increased. Tapping, tapping, and slag operations were carried out approximately 10 times a day, each with an allowance of 2.5 mm per round, but once the iron content at the bottom of the hearth began to drop, the slag operation began. In less than 2 hours, the slag in the furnace started to come out from 1", and subsequently, the time for tapping slag became too short and rj
One. In this way, for two weeks the wheat was tapped.

[tB for raI4 1.5 to 11-I] 6 iHI
I started to do 1 so Dn. 11 throws, η-11 solidified layer at the center'-1-dead,
There is no large aggregate of charged coke called Man-1, and 71-iF, is) Iψ method-1-t] is Urahinjin (
It is thought that the 1HT1 overflow channel of the 1'H slag formed from the L part to the 1st layer of white kotsusu. However, due to the lower temperature of the entire furnace bottom, the solidification of hot metal slag, etc., the liquid permeability of the coke filling becomes worse, and the amount of hot metal slag dripping into the center of the furnace bottom decreases, causing the center of the furnace bottom to - It will be around 1, when low T' products will become available. At the same time, the flow of hot air blown into the tuyere toward the furnace center is obstructed.
The tendency of the heat ridges to pass toward the furnace wall is promoted. In this case, the gas flow bed becomes too large on the furnace wall surface which is at a level H from the wall, and lifting onto the wall causes slip (rapid fall of the charge) and redness.Usually 1.O
Most slips of more than 5 m are considered to be QIEs, but under the above-mentioned conditions, they occur 2 to 3 times a day, and abnormal slips of more than 5 m, resulting in damage to members, water puddles, etc. There may be a sudden drop in the hot metal rush level due to the fall of the cap onto fμ. As the amount of slag increased, slipping phenomena began to be observed.The bottom temperature of the furnace began to show a tendency to decrease, and solidification began to occur.
In addition to increasing the brightness of the 1 m line, the cold nozzle 41 on the bottom and side walls of the reactor was adjusted according to the estimated 1 m solid layer distribution.
control has started. That is, +1. The eels shown in Fig. 7 showed a tendency to grow significantly from the center of the hearth bottom to near the middle of the hearth bottom positive area. Therefore, the direct cooling of this part should be reduced from 11μ to 10~
It suddenly decreased to 30%. At the same time, the operating conditions were changed, such as by increasing the 1-gas flow rate and changing the charging profile to send as much hot air as possible to the center of the furnace. As a result of these patrols, the furnace was restored to +1 (temperature low Ft & approx. Therefore, the solidified layer thickness at the center of the furnace bottom became considerably thinner, and the heavy liquid resistance (of the hot metal slag) also became considerably smaller. Since it is thin, the cooling capacity of the direct portion of the hearth is returned to the state before the cooling of the hearth τ1, and the operation is continued with 30 latches for the center of the hearth.
It continued. '12 Since the constant operation continued for about one month, all operation conditions except bottom cooling were returned to their original state, and the distribution and conditions of the solidified layer were confirmed. The company continued to operate stably under reduced pressure of 4. With conventional methods, it is impossible to confirm the direction of change of the four coagulation lines 14 in such a short period of time, so it is impossible to confirm the direction of change of the four coagulation lines 14 in such a short period of time. It is clear that this method is not suitable for long-term furnace body management in a multiple blast furnace, let alone for quick loading at one time. (Early fruit of the invention) The state of erosion, fecal matter and the distribution of the solidified layer at the bottom of a blast furnace can be ascertained at a glance, thereby providing long-term and short-term protection of the bottom of the blast furnace. Optimum control of the distribution and condition of the embankment is carried out quickly and accurately, stabilizing the operation, and prolonging the life of the bottom refractory and, ultimately, the blast furnace. Fm logic theory of 4th drawing Figure 3 shows 11 examples of the transmission τ~batobori 4-The hearth temperature soup 14, and Figure 3 shows the calculation boundary line (cross-sectional boundary line) according to the 1-point boundary method.1-Explanatory diagram , Figure 4 shows the hearth r scale calorimeter (γ
An example? Show・I-f Its +! 1 i Explanation: Figure 6 is an explanatory diagram showing the process of estimating the solidified layer at the bottom of blast furnace 1. Figure 8 shows the width of the solidified layer line.・This is an explanatory diagram showing the original. Figure 1 Figure 2 o 6 Figure 31x1 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Procedure Sleeve Book July 2511 1, 1982 1. Display of the incident Showa 59 year T!?, 41 Application No. 87477 2. Name of the invention Welding, furnace t @ foil method: 3. %li if: to do 'l l'l-1 nomon IM Q\permission νn person (125)
0 in the "Detailed Description of the Invention" in the Kawasaki Steel Co., Ltd. specification. Y(7, Contents of capture iE (>JI#(]1ilf')) (Rime #Il book 7 negative 1st line "each isotherm J" to each isothermal 1 line 7j 3)
Correct. (2) Correct "equal crosstalk" in line 9 of page 9 to "equal crosstalk?" and correct "heat flux" in line 14 of the same contribution to "heat flux." (3) Formula (5) on page 15, lines 8 to 4 is corrected as follows. [u@(!i, scarcity)=l/4πR・・・・・・・・・
...(5) q@(one color) = θu@(color i, poor)/θn
''□ [4) Same item] 5-negative line 15, correct "lack of points" to "1 point of work". (5) Correct equation (7) in the first line of page 16 as follows. rn=(n,,n2.n8)=(5,cosθ,n,S
in θ, 5, )−=(7) J (6) Correct “θ; 0” in the third and fourth lines of No. 16i to “θ′=0”. (7) [Element Sj J in the 18th negative 15th line]
. j” Correct.・(8) Formula (18) on page 19, line 8 of the same document is revised as follows. ``Jau = (△zj/g) ni - scold) ・・・・・・・・・(
1B) J(9) "Erosion line" on page 24, line 8 of the same page is changed to "
Corrected to "solidified layer line". (10) In the 8th line of page 26, ``I said it for the first time'' is corrected to ``1 I said it for the first time.'' 1 In the 8th line of the same page, ``do'' is corrected to ``do''. (11) On page 27, line 8, [Figure 6 is corrected to ``Figure 7''. Representative patent attorney Akihide Sugimura i゛・1 person Saigai □゛;-; to the effect,・ 1□11

Claims (1)

[Claims] 1. When operating a blast furnace while monitoring the bottom of the furnace,
A method of operating a blast furnace including the following steps. Law. (a) A step of detecting the hearth bottom temperature using a plurality of temperature sensors arranged inside the hearth refractory and/or on the outer surface of the hearth refractory; (b) A step of detecting the maximum temperature in (a). [Cheng, (C)
From the temperature in (b), use the boundary/element method to reach the bottom of the furnace, and heat transfer 1i as an axially symmetrical body with the axis of symmetry at the heart of the furnace 'Il+.
(a) The process of predicting the stable shape of the hearth bottom refractory by carrying out one-dimensional analysis.
Step of detecting the IFiA degree, (e) Based on the temperature in (d) and the erosion shape of the bottom l refractory predicted in (C), the boundary element method is applied I+-1 to the bottom of the furnace, and the The process of predicting the solidified layer shape 1 of the in-furnace melt generated on the eroded hearth bottom refractory by conducting heat transfer analysis as an axisymmetric body with axis symmetry, and (f) the solidified layer of (e) Controlling the furnace operation conditions based on the shape, its lI4 and distribution, and the furnace operating conditions, including the bottom cooling conditions, to prevent the erosion and growth of the bottom refractory of (C) above.