Single vessel blast furnace and steel making/gasifying apparatus and process

Abstract

A blast furnace for use in an apparatus such as a steel making apparatus or a gasifier includes a crucible having a tap hole for discharging molten slag therefrom. The furnace includes a lance for introducing fuel and oxygen into the crucible and instrumentation for continuously measuring characteristics of molten slag discharged through the tap hole to control processing of fuel and oxygen in the crucible. In one application, a single vessel steel-making apparatus includes a crucible having a first tap hole for discharging molten slag therefrom and a second tap hole for discharging molten steel therefrom and includes an additional lance for introducing a carbon reducing oxygen blast into a mass of molten steel in the crucible.

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 629,486, filed Nov. 19, 2004 and U.S. Provisional Application No. 60 / 635,117, filed Dec. 10, 2004.BACKGROUND OF THE INVENTION [0002] This invention relates to the control of continuous and direct iron-making or gasification using pulverized or finely ground coal, iron ore (where applicable) and other materials and unique sensors and computer control techniques and methods in a continuous smelting process such that through the judicious application of these specialized sensors and techniques that this present invention does not require people to interface with the process directly except by keeping the lock hoppers full of previously pre-heated (not shown) feed ingredients, and two lock hoppers are used for each ingredient to insure continuous and interrupted feeding of materials. [0003] Much of present steel making is manually controlled with manual sampling of ...

AI Technical Summary

Benefits of technology

[0005] A direct and continuous controlled smelting and low-grade steel making process or coal or carbon gasification which involves blasting a mixture of pulverized ore (but not if just a gasifier), coal, and a flux mixture(s) through a concentric water cooled downward lance close into a molten slag, with ore mix flowing between the outer cooled shell and inner core air blast tube which expels air / oxygen mixture at high velocity onto the top of the molten slag and steel layers, and to make steel with air / oxygen blast under the molten layer from the base of the crucible distributed evenly through a fine bubbling diffuser mounted within the crucible floor so as to reduce carbon in the molten iron, means to separately meter ore mix ingredients from lock hoppers with bubble-tight valves to prevent gas from flowing back though the hoppers, and with in-line mixer before entering the concentric lance, and with CO2 / CO and temperature exit gas measurement instrument with exit gas concentric pipes allowing heating of inlet air / oxygen blast, including circulating such air / oxygen within the top metal plenum of the furnace with inner shell made of high temperature steel alloys enabling achievement of 1200 F air / oxygen blast, and it has slag and low-grade steel outlet trough with above laser spectrometer measurements to determine chemical composition of both flows, and crucible vertical scanning nuclear gage of molten steel, slag and fresh mix layers to determine their vertical profile density and relative depths and placements, all this instrumentation so as to combine and with suitable computer control and optimizing algorithms and software to properly control preheated ore mix feed rate and composition, levels of molten iron, air / oxygen blast rates, and to manipulate molten levels using either an actuated tap hole plug controller or refrigerant to freeze a portion of the tap hole exit area or eddy current inducing forces to slow down steel exit flow so as to provide reliable backup methods of slag and steel flows so as to accurately maintain molten steel and slag level set points within the crucible, all to produce a quality low-grade steel output with proper carbon, sulfur and potassium contents to the maximum practical extent so as to optimize steel making within one vessel in terms of quality and production requirements and to maximize the overall cost effectiveness of process of smelting and steel-making or gasification.

[0009] From the in-line mixer, a vertical pipe with an enlarged section where the water cooled lance section begins and where the hot air / oxygen enters through the outer cooled enlarged shell into the center air blast tube, whereby such cooled lance enlargement is sufficient for all feed materials to flow at maximum rates easily passing by the narrow vertical rectangular tube penetrating into the lance outer core on one side to feed the center circular round tube of the lance with hot blast air / oxygen.

[0011] The upper shell of the furnace with insulated outer layer and high temperature steel alloy inner layer allow the inner layer to finish heating the pre-heated air / oxygen blast to 1200 F, designed with sufficient inner surface area of the exposed upper furnace to achieve these final blast temperatures at full load steel flow given that such allow inner steel alloy surfaces may be coated with ceramic or other high temperature material to additionally protect the inner steel shell from corrosion and provide sufficient insulating layer to prevent excessive temperature from melting or excessively lowering the strength of this steel alloy. However, in any event, this upper furnace steel section would be supported above by a frame (not shown) surrounding the furnace on its sides as necessary.

[0014] Also to further assist in steel or molten flow control, the outer steel tap hole ceramic pipe can be wrapped with refrigeration coils through which refrigerant at various temperatures and flow rates can be used to solidify steel to form smaller or larger openings tap hole openings to control the flow of molten steel out. Or, further molten steel and slag flow control reliability is achieved with an outer tap hole tapered plug usually used to control such molten steel flows with suitable actuator, and readily available in the art. Or, the bottom hole can be arranged to use a tapered plug valve for flow control.

[0015] These flows of slag and steel into a trough of sufficient volume and weir dam sufficiently higher than the tap hole to cover the tap hole such that the velocity of the flow does not overly agitate flow over the weir for weir vertical level measurement purposes. A radar or sound type level measurement instrument locate above the weir can accurately determine the flow height in the weir notch to measure the volume of slag or steel flowing over the weirs.

[0028] Thus, it can be seen that this invention teaches a very advanced method of continuous steel making and / or gasification and uses the most modern combination of instruments and sensors to accomplish this, and it teaches a unique arrangement of equipment and process to avoid the need for coke and expensive recuperator to preheat air / oxygen blast to proper temperatures, and finally, optimization algorithms are suggested such that those skilled in the computer programming arts in combination with steel process engineer experts in acid or basic steel making processes could enable such software to take advantage of with the instrument signals provide to gain precise and accurate control over the process including ingredient mix ratios and all material flows to optimize steel outflow rates with quality for maximum economic advantage with a minimum of labor input and capital cost.

Problems solved by technology

Similarly, gasifiers do not practice the art of a molten slag pools or control thereof of sufficient depth to recover metals that sink to the base for recovery or that more easily makes a saleable aggregate that such practice can make possible.

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