JPS6350287Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a top-blown steelmaking lance that incorporates both a powder injection passage and an oxygen supply passage. This invention relates to the improvement of a long tubular flow path for blowing powder that is built into a lance for blowing powder. (Prior Art) Molten iron charged into a converter is decarburized by oxygen blown in from a lance, and the temperature of the molten iron rises due to the heat of the decarburization reaction. In recent years, it has become common to add pulverized coal or the like as a carbon source in order to further enrich carbon, which serves as a heat source. In this type of pulverized coal addition, high thermal efficiency, that is, high carbon content addition yield can be obtained by blowing the pulverized coal into molten iron at high speed. Generally, when trying to eject powder at high speed using gas as a carrier,
It is essential to gradually increase the gas flow velocity and secure the acceleration time and acceleration distance of the powder, and in a top-blown converter, one way to make this possible is to use a long flow with a total length of about 20 m. A road becomes necessary. Conventionally, for the long flow path for powder injection in a top-blown converter, a lance dedicated to powder injection, which is separate from the oxygen supply lance, has been installed for the injection of deoxidizing agent, etc. Ta. When adding pulverized coal,
JP-A-58-144409 or JP-A-60-
Powder injection channel 1 as described in the technology disclosed in No. 46349
It is common practice to use a lance that also functions as the oxygen supply channels 2 and 3 (see FIG. 5). and,
Long channel 1 for powder injection in this type of lance
Most of the length of the flow path is straight, and the outlet end has a shape in which the diameter is gradually reduced while discharging, or the diameter is once reduced using a tapered pipe, etc., and then straight again. A short nozzle is installed, such as a shape that discharges via a pipe, or a medium narrow tapered shape that reduces the diameter and then increases again towards the opening end. The tip attachment method was considered the best. (Problems to be solved by the present invention) The long flow path for powder injection built into a conventional transformer is similar to the flow path for gas such as a lance for blowing acid, and based on the concept and experience, almost all of the long flow paths for powder injection are For a long time, the main type of nozzle used was a straight pipe with a short medium-to-narrow convergent nozzle attached to the outlet end, but as a result of recent research, a long tubular flow nozzle was used for powder injection. It was found that it is more suitable for the entire channel to have a medium narrow tapered shape, and a long tubular flow channel with an integral structure as shown in Fig. 4 was adopted, and the powder injection performance was improved. I saw a significant improvement. However, this type of long tubular channel having an integral structure is (a) difficult to manufacture, therefore requiring a long period of labor and high cost. (b) Even if the inner wall of the tubular flow path wears out, repair is extremely difficult. (c) There were problems such as the implementation of anti-wear measures in advance was almost impossible in actual work. This invention was developed to solve the above-mentioned problem of the long tubular flow path installed in the conventional lance, and has a structure that efficiently increases the velocity of powder, which is a necessary condition for the flow path. It is an object of the present invention to provide a lance that is easy to manufacture and that can be easily made wear resistant. (Means and effects for solving the problem) The present invention provides a steelmaking lance that is equipped with a long tubular flow channel for pumping and ejecting powder together with gas at high speed. Cross over,
It is constructed by alternately combining a plurality of straight pipes with different inner diameters and connecting pipes with tapered inner diameters, and the inner diameter substantially gradually increases from near the center of the entire length of the flow path toward both ends. The reason is that a long tubular channel is formed integrally with the channel. A long tubular flow path according to the present invention will be explained with reference to an embodiment shown in FIGS. 1 and 2. As shown in Fig. 2, a plurality of straight pipes 1A, 1B, 1C, 1
Prepare in advance tubes with different inner diameters, such as D and 1E. On the other hand, these straight pipes 1A, 1B, 1C,
Connecting pipes 1a, 1b, 1c, and 1d having tapered inner diameters are prepared as members for connecting 1D and 1E. These straight pipes and tapered connecting pipes are sequentially assembled as shown in the drawings and integrally connected by means such as welding as shown in FIG. 1. Then, the diameter is successively changed from the powder inlet portion to smaller values, and then the diameter is changed to a larger value again from the minimum diameter. The tapered connecting pipe may be relatively short compared to the length of the straight pipe. In addition, when this long tubular flow path is installed inside a steelmaking transformer and used for powder injection, the powder is pumped at high speed while colliding with the inner wall of the tube, causing wear on the inner wall, especially at the connection outlet. The closest parts, for example, parts 1c and 1D, are severely worn. However, since the present invention has a combination structure of a straight pipe and a connecting pipe, this part can be replaced relatively easily, and as a wear-resistant measure for this part, as shown in FIG. 1D
Effective measures to prevent localized abnormal wear can be easily implemented, such as coating the inner surface with a wear-resistant material such as ceramics. (Example) The table below shows an example in which the long tubular flow path shown in FIG. 1 was manufactured to be used as a flow path for pulverized coal injection installed in a top blowing lance for converter steel manufacturing.

[Table] The results of using an actual steelmaking lance with a long tubular flow path fabricated and internalized according to the above specifications show that there is no operational difference compared to using a conventional lance with a long tubular flow path inside. It was in good condition with no problems. (Effects of the invention) The following advantages were obtained by using the long tubular channel of the invention. (A) Easy to manufacture and manufacturing cost is 1/6 compared to conventional products
It became. (B) Since it has an integral structure with combined connections, parts can be replaced. (C) Since a straight pipe section was obtained, it became possible to easily take measures against wear. (D) By taking measures against wear, we were able to extend the lifespan by about 6 times. As described above, by using the long tubular flow path for powder injection of the present invention, the overall merit was that maintenance costs could be reduced to about 1/20. In addition, the life extension effect has greatly improved operational problems, such as equipment downtime and interruptions in operation due to damage to the powder injection channel.

[Brief explanation of the drawing]

Figure 1 is an overall view of the long tubular flow path for powder injection of the present invention, Figure 2 is a conceptual diagram of the long tubular flow path of the present invention before assembly, and Figure 3 is the length of the long tubular flow path of the present invention. FIG. 4 is a partial view of a long tubular flow path showing the inner part of the ceramic; FIG. 4 is a schematic diagram of the entire long flow path for powder injection of an integrated structure in a conventional lance; FIGS. 5 a, b, c is an enlarged view of the tip of a conventional lance. 1...Powder injection channel, 1A, 1B, 1C,
1D, 1E...straight pipe, 1a, 1b, 1c, 1d...
... Tapered connecting pipe, 2 ... Oxidation flow path (for decarburization blowing), 3 ... Oxidation flow path (for secondary combustion), 4 ...
Ceramics inner sleeve.

Claims (1)

[Scope of utility model registration request] A steelmaking lance with a long tubular flow path that pumps powder together with gas at high speed and ejects it.
The flow path is constructed by alternately combining a plurality of straight pipes with different inner diameters and connection pipes with tapered inner diameters over almost the entire length of the lance, and the flow path is formed from approximately the center of the entire length of the flow path toward both ends. 1. A steelmaking lance having an elongated tubular flow path for powder injection, characterized in that the elongated tubular flow path is integrally formed so that the inner diameter substantially gradually increases.