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US3304171A - Method of controlling the operation of a blast furnace - Google Patents

Method of controlling the operation of a blast furnace Download PDF

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Publication number
US3304171A
US3304171A US290783A US29078363A US3304171A US 3304171 A US3304171 A US 3304171A US 290783 A US290783 A US 290783A US 29078363 A US29078363 A US 29078363A US 3304171 A US3304171 A US 3304171A
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US
United States
Prior art keywords
optimum
blast
wind
pressure
furnace
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
US290783A
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English (en)
Inventor
George H Mccleskey
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.)
United States Steel Corp
Original Assignee
United States Steel Corp
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
Application filed by United States Steel Corp filed Critical United States Steel Corp
Priority to US290783A priority Critical patent/US3304171A/en
Priority to DEU10836A priority patent/DE1292680B/de
Priority to GB26181/64A priority patent/GB1072622A/en
Priority to NL6407248A priority patent/NL6407248A/xx
Priority to LU46392D priority patent/LU46392A1/xx
Priority to ES301411A priority patent/ES301411A1/es
Application granted granted Critical
Publication of US3304171A publication Critical patent/US3304171A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B7/00—Blast furnaces
    • C21B7/24—Test rods or other checking devices
    • 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 to a method of controlling the operation of a blast furnace and particularly an iron producing blast furnace.
  • the operation of a blast furnace is complex and many methods have been suggested and used for controlling its operation. For example, it has been suggested to control the air or wind to the individual tuyeres. Other methods are based upon maintaining a pre-set top pressure. Still another method depends upon a drop of pressure across the burden of the furnace. However, none of these methods have proved entirely satisfactory, probably because they do not take into account the majority of all of the variables which contribute to the operation of the blast furnace.
  • blast pressure the condition of the gas leaving the top of the furnace, wind rate and moisture in the wind.
  • the blast pressure and the top gas condition are variables which depend upon the type of burden in the furnace and the operating practice as it relates to the quality and quantity of iron produced.
  • the top gas condition may be indicated by the percent of CO and/ or H2 content, by its temperature or by its B.t.u. content.
  • Another object is to provide such a method in which the blast pressure and the top gas condition are used as sensors and the wind rate and moisture content of the wind are varied to obtain the desired result.
  • Still another object is to provide such a method which corrects for random or permanent changes in the raw materials before the effect thereof is apparent to the operator.
  • a further object is to provide such a method which will increase the coke eiliciency and utilize thewind more efiicently.
  • a still further object is to provide such a method which results in smoother operation of the furnace, more efficient slag control and more uniform chemistry of the iron produced.
  • FIGURE l is a schematic view of a blast furnace and its auxiliary equipment.
  • FIGURE 2 is a chart utilized in the practice of the method of the invention.
  • reference numeral 2 indicates a blast furnace having the usual hearth 4, bosh 6, stack 8, large bell 10, small bell 12 and distributor 14.
  • Raw materials including coke, limestone and iron ore are supplied to the top of the furnace through the usual skip hoist 16.
  • the blast furnace gases pass from the top of the furnace and then down through a downcomer 18 to a dust catcher 2t).
  • a bustle pipe 22 surrounds the blast furnace 2. Air is supplied to the bustle pipe 22 and hence to the tuyeres 24 through a hot blast line 26.
  • a blower 28 feeds cold air through a cold blast line 30 to a stove 32 where it is heated before being delivered to the hot blast line 26. All of the equipment described is conventional.
  • the blower 28 can be controlled to vary the amount of air delivered by means of a control 33 and means 34 are provided to measure and record the wind rate in standard cu. ft. per minute.
  • a recording gage 35 is provided at the bustle pipe to measure the blast pressure in lbs. per sq. in. gage.
  • Means 36 are provided to measure and record the moisture in grains per cu. ft. of air in the hot blast line 26.
  • the amount of mois-ture in the air in the cold blast line 30 is varied by means of a steam jet 38.
  • a temperature responsive device 4t) is provided in the downcomer 18 to measure and record the top temperature of the gas.
  • a gas analyzer or Btu is provided in the downcomer 18 to measure and record the top temperature of the gas.
  • the temperature responsive device may be used in place of the device 46, but the temperature responsive device is preferred because of its simplicity and hence the invention will hereinafter be described with the temperature reading as illustrative. It will be understood that the devices 32, 33, 34, 36, 3S and 4t) are all conventional and that the readings need not be taken at the exact positions indicated.
  • a charge is one complete filling sequence usually requiring two bell dumps into the furnace.
  • FIGURE 2 In order to carry out my invention I have developed the chart of FIGURE 2 based upon the above equation.
  • Column 1 includes a slidable strip 42 on which is indicated actual bustle pressure in lbs. gage.
  • Column 2 indicates the correction in wind volume in standard cu. ft. dependent upon actual bustle pressure.
  • Column 3 indicates moisture correction in grains per cu. ft. based upon actual bustle pressure.
  • Column 4 includes a slidable strip 44 on which is indicated actual top temperature in F.
  • Column 5 indicates the wind volume correction in standard cu. ft. based upon actual top temperature.
  • Column 6 indicates moisture correction in grains per cu. ft. based upon actual top temperature.
  • Row 46 across all six columns may be termed the adjustable base row and Columns 2 and 3 have windows 48 and 50 in this base row.
  • a slidable strip 52 having numbers thereon corresponding to total wind volume is slidably mounted below Column 2 and a similar slidable strip 54 having moisture content in grains per cu. ft
  • the top temperature is varying about a level higher than this, the moisture content should be increased until the desired level is reached. If the increased moisture begins to cool the hearth more than is desired for current operating requirements the amount of coke should beincreased. If the top temperature is Varying about a level below that desired the moisture should be reduced and if this results in the hearth heating up more than is desirable a decrease in coke is made. This operati-on is continued until the levels of 325 to 375 F. top temperature and 12 to 14 grains moisture is obtained.
  • the operator reads the blast pressure and top temperature recorder charts and estimates the average for the preceding time period. I have found that this period should not be less than three minutes since at least this length of time is required to make the necessary control changes and have the changes reiiected in the operation of the furnace. If automatic controls are used this minimum time interval can be used. However, in some instances, changes every six minutes may give best results and when the control is done manually longer periods may be necessary from practical considerations. In one particular instance, .satisfactory results have been obtained with manual operation and readings and adjustments made every half hour. In most cases periods longer than a half hour will be unsatisfactory, unless the charge materials are particularly uniform and of the best quality.
  • the optimum wind rate is decreased and the moisture content increased. If the actual blast pressure is lower, then the optimum wind rate is increased and the moisture c-ontent decreased. If the top temperature is higher, then the optimum wind rate is decreased and the moisture content increased. If the top temperature isbelow the optimum the wind rate is increased and the moisture content decreased. In each of these cases the increases and decreases are directly proportional to the variance from the optimum. The amount of decrease in wind rate due to variance in blast ypressure is twice the amount of the increase for the same variance ,from the optimum blast pressure.
  • the strip 42 is moved until 24 appears in row 46 and strip 44 is moved until 370 appears in row 46.
  • the strip 52 is moved until 76,000 appears in window 48 and strip 54 is moved until 15 appears in window 50.
  • the moisture is reduced back to 15.0 grains per cu. ft. and the wind is reduced back to 76,000 cu. ft. per min.
  • the bustle pressure has decreased to 23 lbs. and the top temperature to 350 F. the following changes are made:
  • the wind volume must be increased 250 cu. ft. due to the lower blast pressure and 240 cu. ft. due to the lower temperature.
  • the moisture must be reduced 0.75 grain due to the lower pressure and 0.4 grain due to the lower temperature.
  • the operator will set the blower to deliver 76,490 cu. ft. per min. and adjust the control 38 to give a moisture content of 13.85 grains per cu. ft.
  • the method of controlling the operation oa blastY furnace which comprises determining the optimum blast pressure and top gas condition for operation of the furnace with a given burden and operating practice, and controlling the wind rate and the moisture content thereof.
  • the wind rate being decreased a predetermined amount when the blast pressure is above the said optimum and increased a predetermined amount when the blast pressure is below the said optimum, said increase and decrease being directly proportional to the variance of said blast pressure from the said optimum with the amount of said decrease being twice the amount of said increase forV the same variance from the said optimum blast pressure;
  • the moisture being increased a predetermined amount when the blast pressure is above the said optimum and decreased a predetermined amount when the blast pressure is below the said optimum, said increase and decrease being directly proportional to the variance of said blast pressure from the said optimum with the amount of said decrease and increase being the same for the same variance from the said optimum blast pressure;
  • the wind rate being decreased a predetermined amount when the top gas condition is greater than
  • the method of controlling the operation of a blast furnace which comprises determining the optimum blast pressure and top gas condition for operation of the furnace with a given burden and operating practice, determining the actual blast pressure and top gas condition at intervals, decreasing the wind rate and increasing the moisture content of said wind when the determined blast pressure is higher than the said optimum, increasing the wind rate and decreasing the moisture content of said wind when the determined blast pressure is lower than the said optimum, decreasing the wind rate and increasing the moisture content of said wind when the determined top gas condition is greater than the said optimum, and increasing the wind rate and decreasing the moisture content of said wind when the determined t-op gas condition is less than said optimum.
  • the top gas condition is the temperature of the gas
  • the increases and decreases are directly proportional to the Variance of said blast pressure from the said optimum and directly proportional to the variance of said top gas temperature from the said optimum
  • the amount of said decrease in wind rate due to variance in blast pressure is twice the amount of said increase for the same variance from the said optimum blast pressure
  • the amount of said decrease and increase in moisture content is the same for the same Variance from the said optimum blast pressure
  • the amount of said increase and decrease in wind rate is the same for the same variance from the said optimum top gas temperature
  • the amount of said increase and decrease in moisture content is the same for the same variance from the said optimum top gas temperature.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Manufacture Of Iron (AREA)
US290783A 1963-06-26 1963-06-26 Method of controlling the operation of a blast furnace Expired - Lifetime US3304171A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US290783A US3304171A (en) 1963-06-26 1963-06-26 Method of controlling the operation of a blast furnace
DEU10836A DE1292680B (de) 1963-06-26 1964-06-23 Steuerungsverfahren fuer einen Hochofen
GB26181/64A GB1072622A (en) 1963-06-26 1964-06-24 Method of controlling the operation of a blast furnace
NL6407248A NL6407248A (es) 1963-06-26 1964-06-25
LU46392D LU46392A1 (es) 1963-06-26 1964-06-25
ES301411A ES301411A1 (es) 1963-06-26 1964-06-25 Método para controlar el funcionamiento de un alto horno

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US290783A US3304171A (en) 1963-06-26 1963-06-26 Method of controlling the operation of a blast furnace

Publications (1)

Publication Number Publication Date
US3304171A true US3304171A (en) 1967-02-14

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Family Applications (1)

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US290783A Expired - Lifetime US3304171A (en) 1963-06-26 1963-06-26 Method of controlling the operation of a blast furnace

Country Status (6)

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US (1) US3304171A (es)
DE (1) DE1292680B (es)
ES (1) ES301411A1 (es)
GB (1) GB1072622A (es)
LU (1) LU46392A1 (es)
NL (1) NL6407248A (es)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3439909A (en) * 1965-09-17 1969-04-22 Koppers Co Inc Apparatus for preheating scrap metal
US3519539A (en) * 1967-09-25 1970-07-07 Koppers Co Inc Apparatus for retorting oil shale having a central axial hollow column
US4248625A (en) * 1979-08-06 1981-02-03 Kawasaki Steel Corporation Method of operating a blast furnace

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2980416A (en) * 1958-06-05 1961-04-18 Nat Steel Corp Apparatus for operating metallurgical furnaces

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2980416A (en) * 1958-06-05 1961-04-18 Nat Steel Corp Apparatus for operating metallurgical furnaces

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3439909A (en) * 1965-09-17 1969-04-22 Koppers Co Inc Apparatus for preheating scrap metal
US3519539A (en) * 1967-09-25 1970-07-07 Koppers Co Inc Apparatus for retorting oil shale having a central axial hollow column
US4248625A (en) * 1979-08-06 1981-02-03 Kawasaki Steel Corporation Method of operating a blast furnace

Also Published As

Publication number Publication date
ES301411A1 (es) 1962-12-16
LU46392A1 (es) 1972-01-01
DE1292680B (de) 1969-04-17
NL6407248A (es) 1964-12-28
GB1072622A (en) 1967-06-21

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