Patent US3561743A successfully refreshed from Google Patents.
US3561743A
Expired / Lapsed
US
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Use of stack gas as oxygen potential measurements to control the bof process
Assignee: General Electric Co
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Filing: 1967-10-17
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Granted: 1971-02-09
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Expires: 1987-10-17
Abstract
Abstract This invention relates to a control method and apparatus for a basic oxygen furnace steel making facility of the type having an oxygen lance for supplying oxygen to a molten metal bath within the furnace and means for moving the oxygen lance relative to the molten metal bath for controlling the partition of oxygen supplied by the lance to the molten metal bath. During the course of a heat, conditions are continuously sensed which are indicative of the oxygen content of the molten bath, the oxygen lance height and the oxygen lance flow rate to provide input data relative to the partitioning of the lance oxygen within the molten bath in the BOF vessel. This input data is processed by suitable computation means which derives measurements representative of the temperature, carbon content and oxygen content of the molten bath during the course of the heat, as well as corrective output signals for the lance height and/or lance oxygen flow rate to optimize the process. The output control signals thus derived are then fed back in a dynamic, closed loop to control of the furnace to thereby optimize its operation. In a preferred embodiment of the invention the continuously sensed condition is the oxygen potential of the gases emanating from the furnace. The sensing is accomplished by a gas analyzer which is positioned ahead of any stack gas cleaning equipment located in the stack of the furnace, and which accordingly has a high response speed. The gas analyzer derives output measurement signals indicative of the oxygen partitioning of the lance oxygen, and these output measurement signals are employed to automatically and continuously control the position of the lance and the flow rate of the oxygen supplied therethrough to optimize the same during a heat.
Inventors
- 👤 David L Schroeder
- 👤 David L Lippitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:39
CPC Classifications
G; G05; G05B; G05B13/00; G05B13/02; C; C21; C21C; C21C5/00; C21C5/28; C21C5/30
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
329 words
A control apparatus for a basic oxygen furnace steel making installation of the type having an oxygen lance for supplying oxygen to a molten metal bath within the furnace and positioning means for moving the oxygen lance relative to the molten metal mass for controlling the partition of oxygen therein, the improvement comprising: sensing instrument means for deriving output measurement signals indicative of the oxygen content of the molten bath comprising: stack gas analysis means positioned ahead of any stack gas cleaning equipment located in the stack for deriving measurement signals indicative of the oxygen potential of the gaseous atmosphere in the BOF vessel and the partitioning of the lance oxygen, and further comprising: means for providing measurement signals indicative of the oxygen lance height, the lance oxygen flow rate, and the stack gas flow rate said stack gas analysis means comprising, oxygen partial pressure measuring means for measuring and providing a measurement signal representative of the oxygen partial pressure of the gaseous atmosphere emanating from the furnace, carbon dioxide measuring means for measuring and providing a measurement signal representative of the mole fraction carbon dioxide present in the gaseous atmosphere emanating from the furnace, and means for providing a measurement signal representative of the mole fraction carbon monoxide present in the gaseous atmosphere emanating from the furnace, the measurement signals thus provided being indicative of the oxygen potential of the gaseous atmosphere in the furnace and therefore indicative of the oxygen content of the molten bath, feedback means including computation means for deriving from said measurement signals corrective output control signals for controlling partitioning of the lance oxygen, means for coupling said corrective output control signals from said computation means back to the oxygen lance for dynamically, automatically, and continuously controlling the position of the lance and flow rate of the oxygen supplied therethrough during a heat, and wherein the computation means comprises means for solving the following equation, and deriving its output control signals in accordance therewith:
Claim 2
Dependent Claim
329 words
A control apparatus for a basic oxygen furnace steel making installation of the type having an oxygen lance for supplying oxygen to a molten metal bath within the furnace and positioning means for moving the oxygen lance relative to the molten metal mass for controlling the partition of oxygen therein, the improvement comprising: sensing instrument means for deriving output measurement signals indicative of the oxygen content of the molten bath comprising: stack gas analysis means positioned ahead of any stack gas cleaning equipment located in the stack for deriving measurement signals indicative of the oxygen potential of the gaseous atmosphere in the BOF vessel and the partitioning of the lance oxygen, and further comprising: means for providing measurement signals indicative of the oxygen lance height, the lance oxygen flow rate, and the stack gas flow rate said stack gas analysis means comprising, oxygen partial pressure measuring means for measuring and providing a measurement signal representative of the oxygen partial pressure of the gaseous atmosphere emanating from the furnace, carbon dioxide measuring means for measuring and providing a measurement signal representative of the mole fraction carbon dioxide present in the gaseous atmosphere emanating from the furnace, and means for providing a measurement signal representative of the mole fraction carbon monoxide present in the gaseous atmosphere emanating from the furnace, the measurement signals thus provided being indicative of the oxygen potential of the gaseous atmosphere in the furnace and therefore indicative of the oxygen content of the molten bath, feedback means including computation means for deriving from said measurement signals corrective output control signals for controlling partitioning of the lance oxygen, means for coupling said corrective output control signals from said computation means back to the oxygen lance for dynamically, automatically, and continuously controlling the position of the lance and flow rate of the oxygen supplied therethrough during a heat, and wherein the computation means comprises means for solving the following equation, and deriving its output control signals in accordance therewith:
Claim 3
Dependent Claim
65 words
A control apparatus according to claim 1 wherein the computation means further includes means for comparing an actual instantaneous measured O.U.F. signal to an initially programmed O.U.F. trajectory and for deriving therefrom corrective output control signals for adjusting the lance height and the lance oxygen flow rate to thereby dynamically and continuously control the partitioning of the lance oxygen during the course of a heat.
Claim 4
Dependent Claim
48 words
A control apparatus according to claim 2 further including charge control means for supplying an initial charge of known ingredients under known conditions to the furnace, and means supplying a charge control signal from said computation means to said charge control means for automatically controlling the operation thereof.
Claim 5
Dependent Claim
66 words
A control apparatus according to claim 2 further including coolant addition control means for supplying additives to the bath at a desired point in a heat, and coolant addition feedback means for supplying a coolant addition feedback control signal from the computation means to the coolant addition control means for automatically controlling the supply of additives to the bath at a desired point in a heat.
Claim 6
Dependent Claim
59 words
A control apparatus according to claim 2 further including turn-down control means for turning down the furnace at a desired point in a heat and pouring out the molten metal into appropriate receptacles, and additional feedback means for supplying a turn-down control output signal from said computation means to said turn-down control means for automatically controlling the operation thereof.
Claim 7
Dependent Claim
153 words
A control apparatus according to claim 2 further including charge control means for supplying an initial charge of known ingredients under known conditions to the furnace, means supplying a charge control signal from said computation means to said charge control means for automatically controlling the operation thereof, coolant addition control means for supplying additives to the bath at a desired point in a heat, coolant addition feedback means for supplying a coolant addition feedback control signal from the computation means to the coolant addition control means for automatically controlling the supply of additives to the bath at a desired point in a heat, turn-down control means for turning down the furnace at a desired point in a heat and pouring out the molten metal into appropriate receptacles, and additional feedback means for supplying a turn-down control output signal from said computation means to said turn-down control means for automatically controlling the operation thereof.
Claim 8
Dependent Claim
143 words
A control apparatus according to claim 2 wherein the computation means further includes means for producing an integrated heat output signal representative of the predicted bath temperature and based on a time integration of the initial bath temperature, the lance oxygen flow rate and the time that has elapsed from the beginning of a heat, means for inserting a disposable bomb thermocouple in the molten metal bath at a point in timE just prior to the end of a heat, and means for supplying the actual instantaneous bath temperature signal from said bomb thermocouple to the computation means, said computation means further including means for comparing the predicted bath temperature output signal to the actual bath temperature signal supplied by the bomb thermocouple and for deriving integrated heat balance corrective output control signals for bringing the heat in on a desired end-point temperature.
Claim 9
Dependent Claim
54 words
A control apparatus according to claim 7 wherein the computation means includes means for comparing the actual O.U.F. signal to an initially programmed O.U.F. versus percent carbon content trajectory for the bath and deriving a cutoff control signal therefrom for terminating the supply of oxygen to the bath at the end of a heat.
Claim 10
Dependent Claim
40 words
A control apparatus according to claim 8 further including charge control means for supplying an initial charge of known ingredients under known conditions to the furnace, and means for supplying a charge control means for automatically controlling the operation thereof.
Claim 11
Dependent Claim
63 words
A control apparatus according to claim 8 further including coolant addition control means for supplying additives to the bath at a desired point in a heat and coolant addition feedback means responsive to an integrated heat balance corrective output feedback control signal from the computation means for automatically controlling the supply of additives to the bath at a desired point in a heat.
Claim 12
Dependent Claim
59 words
A control apparatus according to claim 8 further including turn-down control means for turning down the furnace at a desired point in a heat and pouring out the molten metal into appropriate receptacles, and additional feedback means for supplying a turn-down control output signal from said computation means to said turn-down control means for automatically controlling the operation thereof.
Claim 13
Dependent Claim
203 words
A control apparatus according to claim 8 further including charge control means for supplying an initial charge of known ingredients under known conditions to the furnace, means supplying a charge control signal from said computation means to said charge control means for automatically controlling the operation thereof, coolant addition control means for supplying additives to the bath at a desired point in a heat, coolant addition feedback means responsive to a first integrated heat balance corrective output feedback control signal from the computation means for automatically controlling the supply of additives to the bath at a desired point in a heat where required, means for supplying a second integrated heat balance corrective output feedback control signal from the computation means to the oxygen lance for controlling the position of the lance and the oxygen flow rate therethrough under situations where such integrated heat balance control is required in a heat prior to turn-down, turn-down control means for turning down the furnace at a desired point in a heat and pouring out the molten metal into appropriate receptacles, and additional feedback means for supplying a turn-down control output signal from said computation means to said turn-down control means for automatically controlling the operation thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |