CONTROLLING OPERATION AND POSITION OF A LANCE AND NOZZLE ASSEMBLY IN A MOLTEN METAL BATH IN A VESSEL

Abstract

The present invention preferably comprises a system and method for operating and/or positioning a lance and nozzle assembly relative to a molten metal bath in a vessel. Specifically, at least one temperature sensor is provided proximate a tip of the lance and nozzle assembly and at least one temperature sensor is provided on or in the vessel. A processing unit is configured to receive at least one signal from each of the temperature sensors, process the signals to determine the active position of the lance and nozzle assembly relative to the metal bath, and move the lance and nozzle assembly to a preferred position the corresponds to a stage of operation in the vessel.

Claims

1. A method for operating and/or positioning a lance and nozzle assembly relative to a molten metal bath in a vessel, the method comprising: providing a first temperature sensor proximate to a tip of the lance and nozzle assembly, wherein the first temperature sensor is housed by the lance and nozzle assembly, wherein the first temperature sensor is configured to detect a temperature of the tip of the lance and nozzle assembly, and wherein the temperature is converted to tip temperature data; providing a second temperature sensor on or within the vessel, wherein the second temperature sensor is configured to detect a temperature of the molten metal bath, and wherein the temperature is converted to bath temperature data; transmitting the tip temperature data and the bath temperature data to a processing unit; exchanging information between the processing unit and a process operations data module, wherein the information comprises the tip temperature data, the bath temperature data, and process operations data; mapping the tip temperature data and the bath temperature data to a corresponding active elevation of the lance and nozzle assembly; comparing the active elevation to a preferred elevation of the lance and nozzle assembly; and moving the lance and nozzle assembly from the active elevation to the preferred elevation.

2. A system for operating and/or positioning a lance and nozzle assembly relative to a molten metal bath in a vessel, the system comprising: a lance and nozzle assembly having a first elevation in a vessel comprising a molten metal bath; a first temperature sensor proximate to a tip of the lance and nozzle assembly, wherein the first temperature sensor is housed by the lance and nozzle assembly, wherein the first temperature sensor is configured to detect a temperature of the tip of the lance and nozzle assembly, and wherein the temperature is converted to tip temperature data; a second temperature sensor on or within the vessel, wherein the second temperature sensor is configured to detect a temperature of the molten metal bath, and wherein the temperature is converted to bath temperature data; a processing unit configured to receive and exchange data, wherein the data comprise the tip temperature data and the bath temperature data; a process operations data module, wherein the module is configured to exchange data with the processing unit; a lance elevation control, wherein the lance elevation control is configured to receive data from the processing unit, and wherein the lance elevation control is configured to move the lance and nozzle assembly from the first elevation to a second elevation.

3. A method of operating and/or positioning a lance and nozzle assembly relative to a molten metal bath in a vessel, the method comprising: providing at least one temperature sensor proximate a tip of a lance and nozzle assembly; using a processing unit to receive at least one signal from the at least one temperature sensor to determine the temperature of the molten metal bath in the vessel; and using the processing unit to operate and/or position the lance and nozzle assembly based on the temperature which has been determined by the processing unit based on the at least one signal which has been received by the at least one temperature sensor.

4. The method of claim 1, wherein the first temperature sensor is a thermocouple, an infrared camera, a pyrometer, or a resistance temperature detector.

5. The method of claim 1, wherein the second temperature sensor comprises an ultrasonic transceiver.

6. The method of claim 1, wherein at least one of the tip temperature data and the bath temperature data is wirelessly transmitted to the processing unit.

7. The method of claim 1, wherein the moving the lance and nozzle assembly from the active elevation to the preferred elevation is automated to prevent dunking of the tip of the lance and nozzle assembly into the molten metal bath.

8. The system of claim 2, wherein the first temperature sensor is a thermocouple, an infrared camera, a pyrometer, or a resistance temperature detector.

9. The system of claim 2, wherein the second temperature sensor comprises an ultrasonic transceiver.

10. The system of claim 2, wherein at least one of the tip temperature data and the bath temperature data is wirelessly transmitted to the processing unit.

11. The system of claim 2, wherein the lance elevation control is automated to prevent dunking of the tip of the lance and nozzle assembly into the molten metal bath.

12. The method of claim 3, wherein the first temperature sensor is a thermocouple, an infrared camera, a pyrometer, or a resistance temperature detector.

13. The method of claim 3, wherein at least one of the tip temperature data and the bath temperature data is wirelessly transmitted to the processing unit.

14. The method of claim 3, wherein the operating and/or positioning of the lance and nozzle assembly further comprising moving the lance and nozzle assembly from an active elevation to a preferred elevation.

15. The method of claim 3, wherein the first temperature sensor is housed by the lance and nozzle assembly, wherein the first temperature sensor is configured to detect a temperature of the tip of the lance and nozzle assembly, and wherein the temperature is converted to tip temperature data comprising the at least one signal; and further comprising the steps of: providing a second temperature sensor on or within the vessel, wherein the second temperature sensor is configured to detect a temperature of the molten metal bath, and wherein the temperature is converted to bath temperature data comprising a second signal; transmitting the at least one signal and the second signal to the processing unit; exchanging information between the processing unit and a process operations data module, wherein the information comprises the tip temperature data, the bath temperature data, and process operations data; mapping the tip temperature data and the bath temperature data to a corresponding active elevation of the lance and nozzle assembly; comparing the active elevation to a preferred elevation of the lance and nozzle assembly; and moving the lance and nozzle assembly from the active elevation to the preferred elevation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings wherein like reference numerals identify like elements in which:

[0027] FIG. 1 is a block diagram of a system provided in accordance with a first embodiment of the present invention; and

[0028] FIG. 2 is a block diagram of a method using the system shown in FIG. 1, provided in accordance with an embodiment of the present invention.

[0029] FIG. 3 is a diagram of a system provided in accordance with an embodiment of the present invention.

[0030] FIG. 4 is a flow chart describing steps of a method provided in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] While this invention may be susceptible to embodiment in different forms, there are shown in the drawings and will be described herein in detail, specific embodiments with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated.

[0032] FIG. 1 is a block diagram of a system 10 provided in accordance with a first embodiment of the present invention. As shown, the system 10 comprises a vessel 12, such as a BOF, for use in a metal making process. The vessel 12 may comprise multiple layers of refractory material, such as fire brick, alumina, silica, etc., as well as one or more internal insulating layers, such as gunite or other shotcrete material. Regardless of the exact structure of the vessel 12, during the metal making process, the vessel 12 contains a molten metal bath 22 that is thermally processed as is customary in the industry.

[0033] As shown in FIG. 1, the system 10 provides that a lance and nozzle assembly 14 comprising at least one temperature sensor 16 is disposed about the vessel 12. The at least one temperature sensor 16 is configured to provide at least one signal to a PLC or processing unit (such as a control center) 18, and the processing unit 18 is configured to process that at least one signal received from the at least one temperature sensor 16 and determine the temperature of the molten metal bath 22 inside the vessel 12.

[0034] The at least one temperature sensor 16 can be either hard wired to the processing unit 18 (such as via hardwire, a fiber optic conductor, etc.), or the at least one temperature sensor 16 can be configured to wirelessly transmit the at least one signal to the processing unit 18 (such as via laser signals, a radio signal, etc.). Regardless, the system 10 can be used to continuously monitor the temperature of the molten metal bath 22 in the vessel 12 over time, and based on the temperature that has been detected, the processing unit 18 can change one or more operating conditions, during production, to arrive at the desired endpoint. The same temperature sensor 16 may also be effectively used, by the processing unit 18, to confirm that the conversion process has reached the desired endpoint condition. In some preferred embodiments, as will be described below, a sensor 16 is located at the tip of the lance and nozzle assembly 14 for detecting a temperature of the lance 14 tip and another sensor 16 is positioned near the molten metal bath 22 for detection of a temperature thereof. In either case, the utility of the real-time sensor (i.e., the at least one temperature sensor 16 and processing unit 18) is its ability to minimize the time and cost required to produce steel.

[0035] The temperature of the slag itself can be measured with the at least one temperature sensor 16 located in the lance and nozzle assembly 14 and the melt temperature inferred from this measurement. This temperature probe reading the inside of the copper tip can be a spring loaded thermocouple, or an IR camera. The time-resolved radiance from the slag and combustion of gases can be correlated to the temperature of the bath. The operating temperature profile exhibits a peak near the start of the heat and falls rapidly to a minimum approximately 250 seconds into the heat. From that point, the radiance gradually rises, while concurrently exhibiting local minima and maxima associated with: 1) variations in combustion activity below the lance; 2) addition of ore, lime, and stone throughout the heat; and 3) changes in lance height.

[0036] Since radiance is coupled with the heat release rate within the combustion zone, the data effectively received (by the processing unit 18 via the at least temperature sensor 16) provides feed-back information for modified lance practice and/or the time and rates of flux addition to arrive at a more uniform radiance level and greater integrated heat release rates at early times in the conversion process.

[0037] Tip sensor measurements (measurement of the temperature of a tip of the lance and nozzle assembly 12 taken by the processing unit 18 via the at least one temperature sensor 16) may also provide an indicator of end point bath carbon content. Based on empirical evaluation of data, it has been determined that measurements pertinent to bath carbon content are consequential only after the heat has progressed for approximately 1000 seconds or more. From this time forward, the radiance exhibits an initial maximum, followed by a decrease to a local minimum, rising again to a local maximum. For many heats, within 50 seconds after the second local maximum or 100 seconds of the local minimum, the carbon endpoint is reached. From a process control perspective, it is preferable to obtain bath carbon content information as soon as feasible before reaching the endpoint to allow time for process correction, if necessary. However, failing this approach, a thermally measured endpoint carbon measurement would also be useful.

[0038] Preferably, the processing unit 18 is configured to effectively use the at least one temperature sensor 16 in the lance and nozzle assembly 14 to calibrate the temperature of the lance while the lance is in a known position relative to the bath. Using the at least one temperature sensor 16, the relative position of the lance and nozzle assembly 12 relative to the bath can be determined by the processing unit 18, indirectly without having to take further measurements, make additional calculations, or exposing anyone to a risk in safety.

[0039] Providing at least one temperature sensor 16 in the lance and nozzle assembly 14 effectively provides a view into the vessel that can be used by the processing unit 18 to decrease process time and energy as well as positioning of the lance. With all the information that is typically collected, furnace owners still have operators manually make operational decisions thereby losing consistency between operators. The purpose of the present invention is to automate the real time data being collected with automated control of the lancing operations. This is done by sending data signals from the at least one temperature sensor 16 to the processing unit 18 via hardwire, fiber optic conductor, laser signals, radio signal, etc. The at least one temperature sensor 16 and the processing unit 18 collectively function to permit analysis of certain bath conditions which might be metallurgical, relate to sound and light, or be pyrometric, etc. This data is received and analyzed by the processing unit 18, and the resulting analysis causes commands to be sent to the lance carriage controls and oxygen valve stand for the beneficiation of the process.

[0040] The arrangement may be utilized with any gas lance or oxygen-oil or oxygen fuel burner lance where some form of sensor or information gathering means is to be incorporated. Preferably, a central tube of the lance and nozzle assembly provides a safe and yet effective construction and shielding means for the cable conductor. The arrangement may also be utilized with any signal or information transmittal method, such as but not limited to light usage or fiber optic transfer medium as well as the transmittal of an electrical signal by cable. The ability to measure the bath temperature in real-time allows the operator to see what the bath is doing over time, instead of relying upon single-point measurements taken, for example, with a thermocouple. This capability can be used to prevent overshoots, reduce processing time and optimize energy usage. Real-time temperature monitoring gives valuable insight into the transient behavior of the bath, thereby ensuring the ability of the measurement to accurately represent the bath as a whole. It provides a safe and economic manner in which the desired result may be achieved. It further automates the control of the oxygen blow and lance position ensuring consistency in operation between operators.

[0041] The present invention is directed to a combination of a lance and nozzle assembly for supplying gas to a basic oxygen furnace. The lance and nozzle include an arrangement to accommodate a temperature sensing device or unit which is adapted to transmit signals providing information in connection with the refractory or contents of the bath contained within the vessel. The arrangement includes a signal transmission by, for example, hard wire or radio transmission to a processing 18, such as a PLC, located in a control center. This PLC interprets the data to provide automatic control for operating or positioning the lance and nozzle assembly.

[0042] FIG. 2 is block diagram of a method using the system shown in FIG. 1, in accordance with an embodiment of the present invention, and is self-explanatory given the description hereinabove.

[0043] FIG. 3 is a diagram of a preferred embodiment of the present invention. System 10 preferably comprises vessel 12, lance and nozzle assembly 14, at least one temperature sensor 16, control suite 17, processing unit 18, elevation 20, molten metal bath 22, lance elevation control 24, and process operations data module 26. As shown, the one or more temperatures sensors 16 may be located in various positions about the system 10, including at the tip of the lance and nozzle assembly 14, a probing mechanism within the vessel 12, or outside the vessel 12 such as in sensor systems comprising ultrasonic transceivers. In a preferred embodiment of the present invention, the system 10 comprises a sensor 16 at the tip of the lance and nozzle assembly 14, and a second sensor 16, preferably in a different location such as in the vessel 12 or outside the vessel 12, configured to measure the temperature of the molten metal bath 22.

[0044] FIG. 4 is a flow diagram of a preferred embodiment of the present invention. The flow diagram is designated with boxed reference letters that are also provided in FIG. 3 to help explain where those steps in FIG. 4 will typically occur in system 10. The locations of these designations in FIG. 3 are exemplary and non-limiting. As shown in FIGS. 3 and 4, the present invention comprises a method for operating and/or positioning lance and nozzle assembly 14 relative to the molten metal bath 22 in vessel 12, the method comprising the steps of:

[0045] A: collecting tip temperature data via sensor 16 at the tip of the lance and nozzle assembly 14, wherein such data is provided to processing unit 18;

[0046] B: collecting bath temperature data via sensor(s) 16, such as that provided in one or more locations other than the lance and nozzle assembly 14, for the molten metal bath 22 in the vessel 12, wherein such data is provided to processing unit 18;

[0047] C: obtaining in process operations data module 26 process operations and parameters data from primary and sub systems of system 10, wherein the process operations and parameters data of the process operations data module 26 and data of processing unit 18 may be exchanged between unit 18 and module 26 either unidirectionally or bidirectionally;

[0048] D: providing information to lance elevation control 24 based on a comparison of data received by processing unit 18 against stored data;

[0049] E: amending the elevation position of the lance and nozzle assembly 14 in relation to the bath 22.

[0050] Mechanisms for obtaining tip temperature data from the tip of lance and nozzle assembly 14 include various means and methods, such as Op-T Temp, pyrometer, thermocouple, infrared temperature sensors, and resistance temperature detectors.

[0051] Mechanisms for obtaining bath temperature data from the metal bath 22 include continuous bath measurement, manual measurement, manual measurement, automated measurement, ultrasonic measurement, and probing.

[0052] The temperature data obtained at steps A and B are preferably mapped to a calculated lance and nozzle assembly 14 elevations 20 via an algorithm as such elevations 20 relating to an operating range at Step C. The operating ranges preferably correspond to a particular processing step in the metal making process of the vessel 12. Step C may comprise a feedback loop, and process operations data module 26 may be connected to and/or informed by an operator's station. Data comprising module 26, including process operations data, may include data from the primary and sub systems of the vessel 12, including anti-slop systems as well as normal operations practices input provided by operators at human machine interfaces.

[0053] At step D, the data processing unit 18 preferably calculates the lance and nozzle assembly 14 elevation 20 and amends the elevation 20 based on the temperature readings in the operating range at Step C. This step comprises the lance elevation control 24, which receives input from the processing unit 18. The elevation 20 is preferably the distance between the lance and nozzle assembly 14 tip and the surface of the molten metal bath 22.

[0054] Step E can be effectuated by various means including automated controls and manual operation controls as prompted by the lance elevation control 24.

[0055] Ideally, the present invention will maintain the elevation 20 at an optimal level depending on the operational stage of the vessel 12.

[0056] If the temperatures reach a critical level where the lance 14 is calculated by the system 10 processing unit 18 to be too close to the bath 22 the lance 14 can be alarmed for manual adjustment override, or it can be programmed to automatically adjust to a proper lance 14 height 20 to prevent damaging or dunking the lance 14 tip in relation to the steel bath 22.

[0057] Any of steps A-E can comprise a wired or wireless transmission of data.

[0058] It is contemplated that additional steps may be deployed the method described herein. The process described herein may be automated, manual, or semi-automated.

[0059] While specific embodiments of the invention have been shown and described, it is envisioned that those skilled in the art may devise various modifications without departing from the spirit and scope of the present invention.