A method for reducing oxygen consumption by using a 6-hole high-flow oxygen lance

Abstract

The application discloses an oxygen blowing method for reducing oxygen consumption by using a 6-hole large-flow oxygen lance, which comprises the following steps: blowing oxygen to a 120t converter by using a 6-hole large-flow oxygen lance, controlling the Mach number of the airflow through the oxygen lance to be 2.2-2.3, using a pressure value of 0.95-0.97Mpa, and controlling the oxygen flow to be 18000-19000m 3 / h, the ratio of the oxygen jet penetration depth to the molten steel pool depth being 0.75-0.80, and the height range of the oxygen lance to the molten pool being 1.3-1.5m. The method can further reduce oxygen consumption, and further improve the metal yield of the converter smelting process.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking technology in metallurgical industry, specifically relating to an oxygen blowing method that uses a 6-hole high-flow oxygen lance to reduce oxygen consumption. Background Technology

[0002] The proper selection of oxygen lances and the control of oxygen supply parameters are crucial for converter smelting. This study focuses on a 120t converter at Baogang Steel Plant (effective internal height 7900mm, molten pool diameter (inner diameter) 4900mm, molten pool depth 1301mm, furnace volume ratio 0.96m³). 3 The applicant has developed an oxygen blowing method using a 6-hole high-flow oxygen lance (see patent document CN102433412A, hereinafter referred to as Document 1). Compared with the traditional oxygen blowing method using a 5-hole oxygen lance, it can shorten the total oxygen supply time of the oxygen lance by an average of 1.5 minutes and reduce the total oxygen consumption per heat of steel by an average of 429 mg / L. 3 Less oxygen consumption means less iron is oxidized by oxygen, thus increasing metal yield. Therefore, further reducing oxygen consumption is crucial for improving metal yield in converter smelting. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides an oxygen blowing method for reducing oxygen consumption using a 6-hole high-flow-rate oxygen lance. The method includes using a 6-hole high-flow-rate oxygen lance to blow oxygen into a 120t converter, controlling the Mach number of the gas flow through the oxygen lance to be 2.2-2.3, the pressure to be 0.95-0.97 MPa, and the oxygen flow rate to be 18000-19000 m³ / h. 3 / h, the ratio of oxygen jet penetration depth to molten steel pool depth is 0.75-0.80, and the height of the oxygen lance from the molten pool ranges from 1.3-1.5m.

[0004] In some embodiments, the 6-hole high-flow oxygen lance is characterized by a throat diameter of 26.47 mm, an outlet diameter of 34.68 mm, and an opening angle of 12.5 degrees.

[0005] In some implementations, the ratio of the oxygen jet penetration depth to the molten steel pool depth is controlled to be 0.80 during the initial stage of smelting, and the height of the oxygen lance from the molten pool is 1.3m.

[0006] In some implementations, the ratio of the oxygen jet penetration depth to the molten steel pool depth is controlled to be 0.75 during the mid-smelting process, and the height of the oxygen lance from the molten pool is 1.5m.

[0007] In some implementations, the ratio of the oxygen jet penetration depth to the molten steel pool depth is controlled to be 0.80 at the end of the smelting process, and the height of the oxygen lance from the molten pool is 1.3m.

[0008] In some embodiments, the 120t converter is a bottom-blowing converter, characterized by a molten pool inner diameter of 4900mm and a molten pool depth of 1301mm. The bottom-blowing system features 12 permeable elements, evenly arranged in a circumferential column shape at the bottom of the furnace, located at a distance of 0.56R from the center of the molten pool circumference (R is the radius of the molten pool). These elements are switched according to different smelting processes, and the nitrogen flow rate is 7-21m³. 3 / min, argon flow rate is 10-16m 3 / min.

[0009] The advantages of this invention are: by optimizing the technical parameters of oxygen blowing in a 120t converter using a 6-hole high-flow oxygen lance, this invention can further reduce oxygen consumption compared to the above-mentioned document 1, thereby further reducing the amount of metal oxidized by oxygen in the converter smelting process, and further improving the metal yield. Detailed Implementation

[0010] The present invention will be described in detail below through specific embodiments. These embodiments are intended to help understand the present invention and are not intended to limit the scope of the present invention.

[0011] Example:

[0012] In this example, the raw materials selected are: 93.2t of molten iron + 17.6t of scrap steel, and a total of 5 heats (1#-5#) are produced. The composition of the molten iron in each heat is shown in Table 1 below.

[0013] Table 1

[0014] C Si Mn P S 4.3 0.62 0.36 0.082 0.046

[0015] The operation of oxygen blowing using a 6-hole high-flow-rate oxygen lance is as follows: a constant-pressure variable-lance operation (meaning the height of the oxygen lance above the molten pool changes) is employed at different stages of smelting. The Mach number of the oxygen flow through the lance is 2.2-2.3, the pressure is 0.95-0.97 MPa, and the oxygen flow rate is 18000-19000 m³ / h. 3 / h. The oxygen blowing technical parameters for each furnace are controlled as shown in Table 2 below. For each furnace of steel, the ratio of oxygen jet penetration depth to molten steel pool depth and the height of the oxygen lance from the molten pool are controlled as follows during the initial, middle, and final stages of smelting: Initial stage of smelting: the ratio of oxygen jet penetration depth to molten steel pool depth is 0.80, and the height of the oxygen lance from the molten pool is 1.3m; Middle stage of smelting: the ratio of oxygen jet penetration depth to molten steel pool depth is 0.75, and the height of the oxygen lance from the molten pool is 1.5m; Final stage of smelting: the ratio of oxygen jet penetration depth to molten steel pool depth is 0.80, and the height of the oxygen lance from the molten pool is 1.3m.

[0016] Table 2

[0017] Furnace number Mach number Pressure value (MPa) <![CDATA[Oxygen flow rate m 3 / h]]> 1# 2.2 0.95 19000 2# 2.2 0.95 18000 3# 2.3 0.96 18000 4# 2.3 0.97 19000 5# 2.2 0.97 18000

[0018] The total oxygen supply time and total oxygen consumption for smelting steel in furnaces #1-#5 are shown in Table 3 below. As can be seen from Table 3, compared with the above-mentioned Reference 1, the oxygen supply time and total oxygen consumption for smelting steel in furnaces #1-#5 have been reduced. Since the amount of iron oxidized by oxygen is reduced due to the lower oxygen consumption, the metal yield has been improved.

[0019] Table 3

[0020] Furnace number Total oxygen supply time (min) <![CDATA[Total oxygen consumption m 3 > 1# 15.6 4399 2# 15.3 4345 3# 15.5 4387 4# 14.9 4246 5# 15.2 4309

[0021] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reducing oxygen consumption using a 6-hole high-flow-rate oxygen lance, characterized in that, The oxygen blowing method is applied to a 120t converter with bottom blowing capability, including using a 6-hole high-flow oxygen lance to blow oxygen into the 120t converter, wherein: The 6-hole high-flow oxygen lance is characterized by a throat diameter of 26.47 mm, an outlet diameter of 34.68 mm, and an opening angle of 12.5 degrees. The 120t converter is characterized by a molten pool inner diameter of 4900 mm and a molten pool depth of 1301 mm. The bottom-blowing system features 12 permeable elements arranged in a circumferential columnar pattern at the furnace bottom, located 0.56R from the center of the molten pool circumference, where R is the radius of the molten pool. The system switches between nitrogen and argon gas according to different smelting processes, with a nitrogen flow rate of 7-21 m³ / s. 3 / min, argon flow rate is 10⁻¹⁶ m³ / min 3 / min; During the smelting process, the Mach number of the oxygen lance gas flow was 2.3, the pressure was 0.97 MPa, and the oxygen flow rate was 19,000 m³ / s. 3 / h; Furthermore, the ratio of oxygen jet penetration depth to molten steel pool depth and the height of the oxygen lance from the molten pool were controlled at different stages of smelting as follows: In the initial stage of smelting, the ratio of the oxygen jet penetration depth to the molten steel pool depth was controlled to be 0.80, and the height from the oxygen lance to the molten pool was 1.3 m. During the mid-smelting process, the ratio of the oxygen jet penetration depth to the molten steel pool depth was controlled to be 0.75, and the height from the oxygen lance to the molten pool was 1.5 m. The ratio of the oxygen jet penetration depth to the molten steel pool depth was controlled to be 0.80 at the end of the smelting process, and the height of the oxygen lance from the molten pool was 1.3 m.