United States Steel Corporation

William A Kolb

Jack F Sigh

Michael J Papinchak

Pete Vignovich

Flux is injected into the oxygen stream being fed to the tuyeres of a steel-refining converter, such as a Q-BOP converter or the like, and the rate of injection is controlled by varying the size of the outlet orifice of the flux-containing tank. The tank is pressurized to the same pressure as the oxygen stream into which the flux is being injected. The weight of flux in the tank is continuously measured and the actual weight is compared with a preset reference weight for each point in time. The difference between the two weights is used to drive a motor in either the forward or reverse direction to open or close the variable-orifice flux tank outlet valve an amount sufficient to adjust the actual injection rate to match the reference weight for a given time. The current weight of flux remaining in the tank is compared with an initial weight; when the difference between the two exceeds a preset total, a signal is generated which causes the motor to close the variable orifice valve. At the same time, a fluid by-pass valve is opened to by-pass the injection apparatus.

Method and apparatus for automatically controlling the rate of flux

A method for controlling the operation of a steel refining converter of the type having bottom tuyeres, each tuyere consisting of a center jet surrounded by annulus jets is disclosed. Controls are provided for blowing oxygen through the center jets and a fuel gas, such as propane, through the annulus jets during the refining step. Purging gases, such as nitrogen and compressed air, are blown through the jets during other parts of the steel making process. By means of switching circuits, the flow of each selected set of gases is established before the previously selected set can be cut off, one set of gases is automatically substituted for another if there is a loss of pressure at the tuyeres, nitrogen is substituted for oxygen and fuel if the flow of either of the latter two gases falls below a predetermined value and tilting of the converter to an upright position is prevented unless there is adequate pressure in the tuyeres. The disclosed method ensures that molten metal will not enter or damage the tuyeres thereby preventing severe damage to the equipment and possible hazards to operating personnel.

Method for controlling the operation of a steel refining converter

This invention is directed to a method and apparatus for controlling the injection of flux into a steelmaking vessel as a function of the differential pressure between the flux containing tank and the main conduit which supplies oxygen to the tuyeres of the steelmaking vessel in the Q-BOP process. A branch conduit diverts a portion of the oxygen stream from the main conduit and flux from a pressurized flux-containing tank is injected into this secondary stream which secondary stream is then recombined with the main stream. The apparatus measures the pressure differential between the main conduit and the flux tank and also compares the actual flux injection rate with a preset reference rate; a voltage signal representing the measured pressure differential and one representing the comparison between the actual and reference rates are compared with each other to provide a signal for controlling oxygen supplied to and vented from the pressure tank to vary the differential pressure between the primary conduit and the tank and thereby control the rate of flux injection into the secondary conduit as a function of this pressure differential. The apparatus also measures the amount of flux injected into the secondary conduit and shuts off the supply when the measured amount equals a preset desired amount.

Method for controlling the injection of flux into a steelmaking vessel

An improved method of optimum burning of carbon monoxide in a carbon monoxide zone (being fed oxygen by a side tuyere) above a molten metal bath in a converter to carbon dioxide is disclosed. The improved method includes the steps of: A. sensing an initial effectiveness signal of the amount of carbon monoxide in the carbon monoxide zone being burned to carbon dioxide at a predetermined point relative to the converter; B. monitoring a continuing effectiveness signal; C. comparing the continuing effectiveness signal with the initial effectiveness signal; and D. moving the side tuyere relative to the converter and adjusting O.sub.2 flow when all possible side tuyere positions are exhausted when the continuing effectiveness signal is greater than the initial effectiveness signal to increase the amount of carbon monoxide in the carbon monoxide zone being burned to carbon dioxide. The apparatus has sensing means associated with the converter for sensing the initial effectiveness signal of the amount of carbon monoxide in the carbon monoxide zone being burned to carbon dioxide at a predetermined point relative to the converter. The sensing means is then operable to monitor the continuing effectiveness signal. Comparison means are connected to the sensing means for comparing the continuing effectiveness signal with the initial effectiveness signal. Tuyere operating means are connected to the comparison means and the side tuyere for moving the side tuyere relative to the converter and adjusting O.sub.2 flow when the continuing effectiveness signal is greater than the initial effectiveness signal to increase the amount of carbon monoxide in the carbon monoxide zone being burned to carbon dioxide.

Method of optimum burning of carbon monoxide in a converter

A method of oxygen refining molten hot metal to steel by blowing an oxygen stream at a predetermined flow rate from an oxygen supply source having a pressure from about 12 to about 18 atmospheres through the molten hot metal from a tuyere located beneath the surface of the molten hot metal and having a tuyere inlet and by varying the rate of flow of a finely divided lime injected into the oxygen stream is disclosed. The method includes the steps of supplying oxygen from the oxygen supply source to the tuyere inlet at the predetermined oxygen flow rate for refining the molten hot metal; controlling the pressure of the oxygen stream at the tuyere inlet at a value which is about three atmospheres less than the difference between the pressure of the oxygen supply source and the oxygen pressure drop resulting from supplying the oxygen stream from the oxygen supply source to the tuyere inlet; injecting the finely divided lime into the oxygen stream at an injection point prior to the entry of the oxygen stream into the tuyere inlet; and increasing the pressure of the oxygen stream upstream of the injection point to maintain substantially constant the predetermined oxygen flow rate.

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Forest Hills Borough, PA, United States of America

William A Kolb