US3853539A - Method for controlling the blast furnace condition - Google Patents

Method for controlling the blast furnace condition Download PDF

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Publication number
US3853539A
US3853539A US00337690A US33769073A US3853539A US 3853539 A US3853539 A US 3853539A US 00337690 A US00337690 A US 00337690A US 33769073 A US33769073 A US 33769073A US 3853539 A US3853539 A US 3853539A
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US
United States
Prior art keywords
furnace
blast
index
sounding
descending rate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00337690A
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English (en)
Inventor
M Yoshiki
Y Murakami
M Ogata
T Yokoi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2701672A external-priority patent/JPS526844B2/ja
Priority claimed from JP10301172A external-priority patent/JPS5229681B2/ja
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Application granted granted Critical
Publication of US3853539A publication Critical patent/US3853539A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • C21B5/006—Automatically controlling the process

Definitions

  • This invention relates generally to a method for digitally judging and controlling the condition of a blast furnace, thereby stabilizing the furnace operation more effectively, and it relates more particularly to a new method for digitally controlling the condition of the blast furnace using the blast pressure index, the fluctuation of the blast pressure in a predetermined period of time and/or the descending rate index, the fluctuation of the descending rate of the charged materials.
  • the fluctuation of the blast pressure is expressed by the amount of variation of the blast pressure in a predetermined period of time which is defined as the blast pressure index or the first furnace condition index.
  • the blast pressure index or the first furnace condition index A significant correlation between this furnace condition index and the slips or partial slips is confirmed.
  • a strong correlation is also confirmed between the strength and fine content of the sinter (-4 mm percent) and the drum index of the coke used in the blast furnace operation.
  • the furnace condition index as defined above can be a standard for controlling the entire furnace condition digitally.
  • the descending rate index or the second furnace condition index is adopted to express the fluctuation of the descending rate of the materials charged from the top of the furnace to thereby judge the furnace condition precisely and promote the highly stabilized operation of the blast furnace by using the descending rate index as another standard for controlling the entire furnace condition digitally.
  • furnace condition indices can, of course, be used at the same time to control the furnace condition precisely.
  • FIG. I is a portion of a strip chart recording the fluctuation of the blast pressure
  • FIG. 2 is an enlarged partial view of a portion of the strip chart of FIG. 1;
  • FIG. 3 is a schematic diagram illustrative of an apparatus for measuring the descending rate of the charged materials
  • FIG. 4 is a chart recording the descending rate of the charged materials measured by the apparatus shown in FIG. 3;
  • FIGS. 5A and 5B are charts recording the descending rate of the charged materials in which stable and unstable conditions of the furnace are shown respectively by 5A and 5B;
  • FIG. 6 is a graph showing the relation between the descending rate index and the number of slips and partial slips
  • FIG. 7 is a graph showing the relation between the blast pressure index and the number of slips and partial slips
  • FIG. 8 is a graph showing the correlation between the descending rate index and the blast pressure index
  • FIG. 9 is a comparative representation of the furnace condition indices measured in a relatively long period of time.
  • FIGS. 10 12 are graphs showing the correlations between each of the various properties of the sinter and the blast pressure index.
  • the blast pressure index or the first furnace condition index is a value represented by the fluctuation length of the blast pressure in a predetermined period of time (Note: the blast pressure is a gauge pressure detected in the straight pipe between the hot stove and the circulating bustle pipe of the blast furnace. At a temperature of approximately 1, I50C, and the average gauge pressure is 2.1 Kg/cm
  • the fluctuation length of the blast pressure is the actual length of the path of the pen recorded on the strip chart which is calculated by the method described below. Measurement of the fluctuation length is best wherein: 480/288 represents fluctuation length corresponding to the unit time, 5 minutes calculated from the scale of the chart;
  • 248 represents width of the chart (full scale in millimeter) corresponding to the blast pressure fluctuation 4 Kg/cm (gauge pressure);
  • the value X is obtained from the above equation l) and is approximately taken as the blast pressure fluctuation length L0.
  • the blast pressure index or the first furnace condition index is obtained by dividing Lo by the length L (480/288) of the strip chart corresponding to the L0. Namely,
  • the first furnace condition index Lo/L 2 This index is calculated and typed out every hour, every shift (8 hours) and every day (24 hours).
  • the descending rate of ore and coke charged from the top of the furnace indicates the fluctuations of the furnace condition. And digital judgment of such fluctuations contributes greatly to furnace operation by making it possible to judge the furnace condition objectively.
  • the descending rate of every 1/2 charge i.e. any one charge of either ore or coke into the furnace, (one charge being defined as one deposit of ore and coke.) is determined by the f w nssqsati n.Qua....
  • Descending Rate The first state (The last state) of sounding of sounding fined as the value of the level at which a new charge of the materials must be made and the term the last state of sounding" is the value of the level when the charging of the new materials is finished.
  • the level is measured with the furnace top side as the standard.
  • N Number of times when the absolute value of
  • These weighting coefficients are predetermined so that the descending rate index is between 1.0 and 2.0 and that the descending rate index is identical substantially with the blast pressure index.
  • the indices are calculated and indicated at every unit period of time and the average values of the indices are automatically calculated by means of, for example, an electronic computer, every 8 hours or 24 hours.
  • the descending of the charged materials is stable in FIG. 5A and unstable in FIG. 5B in which slipping and- /or partial slipping are occurring.
  • the terms slipping and"partial slipping as used herein are defined to indicate respectively a sudden descending of the charged materials of not less than 1,000 mm in 5 seconds as marked X and I a less sudden descending within the range between 500 mm and 1,000 mm in 5 seconds as marked Y.
  • the average value of the descending rate index of 24 hours is found to be in substantial correspondence with the sum of the number of times of the slippings and partial slippings as shown in FIG. 6.
  • the number of times of slippings is weighted double that of partial slippings.
  • the first furnace condition index namely the blast pressure index (average of 24 hours) is contrasted similarly with the number of times of slippings and partial slippings.
  • FIG. 7 clearly shows that there is a relation as may be expressed by a curve of second order between them.
  • FIG. 8 is a graph showing a correlation between the descending rate index and the blast pressure index. Between these two indices there is found a high coefficient of correlation of 0.799.
  • the suggestion for stabilized furnace operation according to the present invention shows that behavior of the blast furnace can be judged clearly and digitally by using the descending rate index of the charged materials and/or the blast pressure index.
  • the degree of stability or instability of the furnace condition can be judged digitally.
  • each tuyer damage is indicated by a small circle. It is very interesting to notice that there is a strong correlation between the degree of the tuyer damage and the two indices.
  • the control level is raised, namely shutter index of sinter changes to not less than percent, fine content of sinter to not more than 6 percent, and further the quality of control standard is raised, namely drum index (Dl of coke increases to not less than 35/Secondly, the blast volume is reduced, for example, from 2,300 Nm /min to 2,200 Nm /min.
  • the third measure is taken, namely the volume of ore per charge is reduced, for example, from 35,000 Kg to 30,000 Kg thereby improving the permeability within the furnace.
  • FIGS. 12 correlations between the blast pressure index and each of the shutter index of sinter, the fine content of sinter and the drum index of coke are shown in FIGS. 12.
  • the shutter index of FIG. 10 is defined as the rate of Kg sinter of oversize of 10 mm screening is dropped four times from the height of 2 m.
  • the fine content of sinter of FIG. 11 is defined as the weight percent of undersize of not more than 4 mm screening.
  • the descending rate index and/or the blast pressure index are defined as the furnace condition indices serving as the operation standard of the blast furnace, fluctuation of the blast furnace condition is judged digitally over a long period of time, to thereby make it possible to take necessary measures quickly to stabilize the furnace condition.
  • the present invention provides an appropriate guide to the computer-aided control of a blast furnace which is generally recognized to be difficult. Working of the present invention has a very great effect.
  • a method for measuring information during opera tion of a blast furnace which comprises detecting blast pressure at a desired position in the blast furnace, recording the detected blast furnace pressure continuously on a strip chart, measuring fluctuation length of recorded blast pressure from the strip chart within a predetermined period of time thereby digitally expressing fluctuation of said blast pressure, determining a first furnace condition index by dividing said fluctuation length by the length of measured strip chart corresponding thereto, and applying said furnace condition index to judge the condition of the blast furnace and promote highly stabilized operation.
  • a method for measuring information during operation of a blast furnace which comprises, measuring a first state of sounding, a last state of sounding and the respective times of the first and last states of sounding, said first state of sounding being the value of a level at which a new charge of material in said furnace must be made, said last state of sounding being the value of a level when the charging of new material is finished; calculating the descending rate of said charged material from the measured first and last states of sounding and the respective times thereof; averaging the value of said descending rate within a predetermined period of time, and obtaining the difference between the value of said descending rate and the average value thereof, thereby to obtain a second furnace condition index capable of judging the condition of the blast furnace.
  • N represents the number of times the absolute value of (average descending rate) (descending rate of every l/2 charge) is within 15 mm/min;
  • N represents the number of times said absolute value is within the range 15.1 mm/min 3O mm/min;
  • N represents the number of times said absolute value is within the range 30.1 mm/min 45 mm/min.
  • N represents the number of time said absolute value is not less than 45.1 mm/min.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
US00337690A 1972-03-15 1973-03-02 Method for controlling the blast furnace condition Expired - Lifetime US3853539A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2701672A JPS526844B2 (fr) 1972-03-15 1972-03-15
JP10301172A JPS5229681B2 (fr) 1972-10-14 1972-10-14

Publications (1)

Publication Number Publication Date
US3853539A true US3853539A (en) 1974-12-10

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US00337690A Expired - Lifetime US3853539A (en) 1972-03-15 1973-03-02 Method for controlling the blast furnace condition

Country Status (6)

Country Link
US (1) US3853539A (fr)
CA (1) CA1006373A (fr)
ES (1) ES412599A1 (fr)
FR (1) FR2176100B1 (fr)
GB (1) GB1430626A (fr)
NL (1) NL158550B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4421553A (en) * 1980-05-06 1983-12-20 Centre De Recherches Metallurgiques Process for operating a blast furnace
US20090013762A1 (en) * 2005-04-08 2009-01-15 Kabushiki Kaisha Kobe Seiko Sho Kobe Steel, Ltd. Apparatus for estimating residual life of blasting vessel, method of estimating residual life, and blasting facility

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2822257A (en) * 1955-06-21 1958-02-04 United States Steel Corp Method and apparatus for controlling blast furnaces
US3581070A (en) * 1968-11-01 1971-05-25 Nippon Steel Corp Apparatus for operating a shaft furnace by detecting the falling speed of the charge
US3719811A (en) * 1971-08-25 1973-03-06 Westinghouse Electric Corp Blast furnace computer control utilizing feedback corrective signals

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1432611A (fr) * 1965-01-15 1966-03-25 Yawata Iron & Steel Co Appareil pour la mesure de la vitesse de déplacement d'une charge dans une enceinteet notamment de la vitesse de descente de la charge dans un haut fourneau

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2822257A (en) * 1955-06-21 1958-02-04 United States Steel Corp Method and apparatus for controlling blast furnaces
US3581070A (en) * 1968-11-01 1971-05-25 Nippon Steel Corp Apparatus for operating a shaft furnace by detecting the falling speed of the charge
US3719811A (en) * 1971-08-25 1973-03-06 Westinghouse Electric Corp Blast furnace computer control utilizing feedback corrective signals

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7913571B2 (en) * 1920-04-08 2011-03-29 Kobe Steel, Ltd. Apparatus for estimating residual life of blasting vessel, method of estimating residual life, and blasting facility
US4421553A (en) * 1980-05-06 1983-12-20 Centre De Recherches Metallurgiques Process for operating a blast furnace
US20090013762A1 (en) * 2005-04-08 2009-01-15 Kabushiki Kaisha Kobe Seiko Sho Kobe Steel, Ltd. Apparatus for estimating residual life of blasting vessel, method of estimating residual life, and blasting facility

Also Published As

Publication number Publication date
DE2312669A1 (de) 1973-09-20
FR2176100B1 (fr) 1977-08-05
GB1430626A (en) 1976-03-31
NL7302804A (fr) 1973-09-18
CA1006373A (en) 1977-03-08
DE2312669B2 (de) 1976-12-30
NL158550B (nl) 1978-11-15
FR2176100A1 (fr) 1973-10-26
ES412599A1 (es) 1976-10-16

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