A gun head structure and method for adjusting the oxygen flow rate of converter top blowing by dual-channel oxygen flow

Abstract

The invention provides a lance head structure and method for double-oxygen-flow adjustment of the top blowing oxygen flow rate of a converter. According to the invention, double oxygen flow channels are adopted, a main oxygen flow ensures the supersonic jet of an oxygen lance, and an auxiliary oxygen flow ensures that the oxygen supply rate is adjusted continuously within a certain range. The lance head structure comprises a plurality of layers of concentrically nested pipes and a multifunctional jet head, wherein the main oxygen flow is jetted into the converter at a supersonic speed and a constant flow rate via a Laval spout and a circular slot spout; the auxiliary oxygen flow passes through the center of the jet head via the central pipe and is directly sent into the converter at a subsonic speed and a variable flow rate; and the auxiliary oxygen flow can also carry converter steelmaking powder and be entrained in the circular slot oxygen flow to be sent into the converter without influencing the Mach number of the main oxygen flow, and a high powder utilization rate is obtained.

Description

technical field [0001] The invention belongs to the field of steelmaking in the metallurgical industry, and in particular relates to a gun head structure and method for adjusting the flow rate of oxygen blown in the top of a converter by a double-channel oxygen flow. Background technique [0002] Converter steelmaking is an important means of steel production, and top-blown oxygen lance is one of the key equipment for oxygen converter steelmaking. The oxygen blowing lance on the top of the converter can convert the pressure energy of oxygen into kinetic energy. At present, the supersonic nozzle design of the single-hole and multi-hole round-hole Lava tube is generally used, and the oxygen supply system is usually a single-gas path high-pressure oxygen. Low alkalinity of slag in the early stage of converter blowing, easy peroxidation, overfoaming and splashing, low dephosphorization efficiency, early transformation of decarburization reaction mechanism in the later stage of b...

AI Technical Summary

Problems solved by technology

Low alkalinity of slag in the early stage of converter blowing, easy peroxidation, overfoaming and splashing, low dephosphorization efficiency, early transformation of decarburization reaction mechanism in the later stage of blowing, reaction between steel slags is far from equilibrium, and oxygen decarburization utilization rate Low, resulting in difficult control of molten steel quality, high consumption of raw materials

The usual solution is to adjust the gun position at constant flow rate or adjust the flow rate at constant gun position, but the operation of lifting the gun will reduce the oxygen utilization rate, and reducing the oxygen flow rate will deviate from the supersonic jet flow design point, affecting the jet stirring effect

Invention patent 89103227.4 proposes a double-channel top-blowing oxygen lance with a central hole and three to four peripheral holes with internal rotation angles. It uses variable lance position and double-channel full variable flow blowing to solve the problem before and after converter blowing. Insufficient agitation strength of molten pool, etc.

One type of solution is to mix the powder into the main oxygen flow and spray it from the Laval hole. The randomly fluctuating fluid density destroys the generation conditions of the supersonic airflow, and it is impossible to achieve a stable supersonic jet; the other type of solution is designed with a dedicated channel for the powder , but the sprayed powder will be swept away by the airflow in the negative pressure zone generated by the surrounding supersonic oxygen flow, which seriously affects the utilization rate of the powder, and lowering the gun position so that more powder enters the molten pool will increase the splash generated during the smelting process , resulting in the risk of gun sticking and even safety accidents. Therefore, the existing converter powder spraying technology is difficult to achieve the expected effect of high-efficiency dephosphorization, which has become one of the difficulties faced by the process of high-phosphorus molten iron in converter treatment.

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