Modular sub-lance

Abstract

The present invention proposes a modular sub-lance (100), as a replaceable part of the lance, comprising two parts: a body (101) and a front module (102). The current mechanism for replacing the body (101) is thus retained, but with the capability, ease, and convenience of replacing only the front module (102).

Description

[0001] MODULAR SUB-LAUNCH

[0002] Field of application

[0003] (001) The present invention relates to a simplification of the mechanism for changing the lower portion of the sub-lance (100) by creating modules that make up this equipment, providing a modularization of said sub-lance (100). The sub-lance (100) is used in converters (112) to obtain information on temperature, oxygen and carbon content in the molten metal through samples obtained during and after the oxygen blowing performed by a lance (113) dedicated to this function. The sub-lances (100) are used in the process called primary refining for obtaining steel. Their performance is determined by the number of times they perform a measurement of any of the information.

[0004] State of the art

[0005] (002) According to Soares (Soares, C., Faria, MAA Steel Refining Operation. Chapter 05. Primary Refining of Steels. ABM. 2016) the sub-lance (100) is the equipment used to measure temperature, oxygen and carbon content and collect a sample of the steel during and after the end of the blowing, without the need to tilt the converter (1 12), shown in the diagram in figure 1.

[0006] (003) According to Maia et al. (MAIA, B. M„ LIMA, W. R„ SANTOS, BOA, NOGUEIRA, AAA, XAVIER, HA “SUB-LANCES - NEWS CONCEPTIONS FOR BEST PERFORMANCES” in AISTech2022 Proceedings of the Iron and Steel Technology Conference, 2022. DOI 10.33313 / 386 / 168), the sub-lance (100), to ensure good steel conditions for casting, has its use determined by the blowing moment. This moment is determined, in principle, by the static control mathematical model that determines a volume of oxygen blown and allows estimating when the decarburization rate advances to the third stage, as shown in figure 2.

[0007] (004) In figure 2, the third stage determines the region called “critical carbon” and thus a reduction in the decarburization rate. From the results of this measurement, also called “intermediate”, a mathematical model of dynamic control guides the blowing to the targeted carbon and temperature results. After the intermediate measurement, the sub-lance (100) can be used to verify the end-of-blowing conditions.

[0008] (005) Regardless of the moment, the sub-lance (100) is subjected to aggressive process conditions, such as high temperature and in some cases, immersion in the emulsion, a metal-gas-slag mixture. This operation requires that the cooling and inerting of its components be efficient, in order to guarantee the correct penetration of the sensor into the bath and obtain (Oncken, M, Junior, JC R Comparative Study of Usiminas Sub-Lance Sensors. Heraeus, 2015):

[0009] • Metallostatic pressure for effective filling of the mold to obtain the steel sample;

[0010] • Sampling in a representative region of the liquid steel;

[0011] • Stability / favorable conditions for measuring bath temperature;

[0012] • Stability / favorable conditions for measuring the solidification temperature;

[0013] • Stability / favorable conditions for measuring oxygen activity. (006) The sub-lance equipment consists of a lance with 03 concentric tubes, of which 02 tubes: the outer tube (103) and the intermediate tube (104) are intended for water cooling. A central tube (105), generally inerted and cooled with nitrogen, through which cables and connections pass, culminating at its lower end with the coupling of a disposable multi-function sensor. Figure 3 shows some sub-lance designs in the state of the art.

[0014] (007) Figure 03 shows changes in geometry in the lower region of the sub-lance (100) and also in the length of the copper sections. These variations are associated with the need for adjustments, in order to mitigate the problems encountered in measurement routines.

[0015] • Adhesion of scale along the body associated with: o Incorrect assembly of the sub-boom (100) on the sub-boom body; o Cooling water flow rate of the sub-boom (100); o Water leakage in the sub-boom body (100); o Geometry of the base edge of the sub-boom (100); o Geometry of the sensor connection; o Extension of the material type of the sub-boom (100) outer tube versus depth of penetration into the emulsion; o Wear on the tube caused by previous scale removal; o Wear on the tube caused by misalignment with passage through the dome and eventual use of a scraper; o Sensor x holder x sub-boom base (100) connection;

[0016] • Misalignment being associated with: o Warping due to asymmetrical heating from the oxygen blast (Zonneveld, PCH Sub-lance installation for carrying out measurements and / or taking samples in a metallurgical furnace. EP 0 280 349 B1. 30 / 05 / 1990); o Influence of the oxygen lance nozzle mounting; o Sludge on the movable hood; o Water leakage onto the sub-lance body (100). (008) According to Maia et alii (MAIA, B. M„ LIMA, W. R„ SANTOS, BOA, NOGUEIRA, AAA, XAVIER, HA “SUB-LANCES - NEWS CONCEPTIONS FOR BEST PERFORMANCES” in AISTech2022 Proceedings of the Iron and Steel Technology Conference, 2022. DOI 10.33313 / 386 / 168), research on equipment in operation in Brazil showed the evaluation of the external diameters of the sub-lances (100). The result of the research is presented in table I.

[0017] Table I. External diameter of the sub-booms x converter capacity.

[0018] Objectives of the invention

[0019] (009) One of the objectives of the present invention is to provide a modular sub-boom (100), composed of an assembly consisting of the body (101) and front module (102) which comprise the replaceable parts of the entire sub-boom assembly (100). (010) Another objective of the present invention is that, from the constructive and assembly form of the body (101) and front module (102), the sub-boom (100) obtains advantages in the process:

[0020] • Reduction of crust on the sub-spear body (100);

[0021] • Reduction of crust on the tip of the sub-lance (100);

[0022] • Increased equipment lifespan;

[0023] Increased accuracy of the first sample measured; • Reduction in sample rejection;

[0024] (01 1 ) It is also an objective of the present invention to contribute to an increase in the number of measurements with the same front module (102) but mainly a considerable increase in measurements with the body (101 ), increasing availability and reducing maintenance costs.

[0025] Summary of the invention

[0026] (012) The present invention proposes a modular sub-boom (100), as a replaceable part of the boom, which will be composed of two parts: body (101) and front module (102). In this way, the current mechanism for replacing the body (101) is maintained, but with the property, ease and convenience of replacing only the front module (102).

[0027] Description of the drawings

[0028] (013) To better understand the components and technical characteristics of the present invention, the attached figures are presented in which:

[0029] - Figure 1: Shows a side view of a BOF converter to exemplify a converter (1 12) with the oxygen blow lance (113) and the sub-lance (100);

[0030] - Figure 2: Presents a graph with the main stages of the blowing process of a steelmaking batch as a function of carbon reduction over time and the field where the sub-lance (100) is used to perform sampling inside the converter (1 12);

[0031] - Figure 3: Presents images of different sub-booms (100) in the state of the art and their main components, outer tube (103), intermediate tube (104) and central tube (105);

[0032] - Figure 4: Presents the proposed sub-boom (100) of the present invention considering the composition in two parts: body (101) and front module (102). - Figure 5: Presents internal components of the invention, spacers (106) and holder guides (107).

[0033] - Figure 6: Shows internal components of the front module (102).

[0034] - Figure 7: Represents the ease of changing the front module (102) in relation to the body (101) of the sub-boom (100).

[0035] Detailed description of the invention

[0036] (014) The present invention presents a modular sub-lance, based on the separation of the sub-lance (100) into two parts: body (101) and front module (102) with the objective of providing quick replacement of the segment that suffers the highest wear rates with repetitive use for sample removal in the converter (112). Figure 4 shows these components. However, the traditional method of replacement from the body of the sub-lance (101) is maintained because some occurrences determine the need to replace the entire segment.

[0037] (015) Figure 5 shows the main components of the sub-boom (100) consisting of: outer tube (103), intermediate tube (104), central tube (105), spacers (106), holder guide (107). The outer tube (103) of the body (101) and front module (102) are made of copper in order to maximize heat exchange between the converter environment composed of the emulsion, a metal-gas-slag mixture, and the cooling water that circulates between the intermediate tube (104) and the outer tube (103). The spacers (106) were applied to ensure correct alignment between the tubes and centering of the holder guide (107), since warping of the sub-boom (100) is frequently observed in repeated measurements in the prior art.Thus, considering that warping will occur during the use of the equipment, the spacers (106) serve the function of ensuring the necessary tolerances to guarantee the replacement of only the tip (108) of the front module (102), functioning as guides for this replacement as can be seen in figure 6.

[0038] (016) The front module (102) is constructed of fitted parts joined by welding. The weld joint (1 11 ) joins the body (101 ) and the front module (102 ). Thus, when it is necessary to replace the front module (102), it is sufficient to remove (using a disc grinder or automatic or manual saw, taking due care not to damage the other tubes, a common practice already performed for removing part of the sub-boom in the present invention) the weld joint (1 1 1 ) that the tip of the front module

[0039] (108) is detached from the extension of the intermediate tube (109) and from the extension of the holder coupling (10) and is removed from the body (101) of the sub-boom (100) as illustrated in figure 7. A new tip of the front module (108) is then fitted, its limits clearly defined by the space between the extension of the intermediate tube.

[0040] (109) and holder engagement extension^ 10) and finally joined to the sub-boom body (101) by means of a new weld.

Claims

CLAIMS 1. Modular sub-boom (100), composed of two parts: body (101) and front module (102), characterized in that the front module (102) can be replaced by removing only one weld joint (111), with the other parts being fitted together.

2. Modular sub-boom (100), according to claim 1, characterized in that the body (101) and the front module (102), in its outer tube (103) and tip of the front module (108) are made of copper and its alloys with the aim of maximizing heat exchange.

3. Modular sub-boom (100), according to claim 1, characterized in that the extension of the intermediate tube (109) and the extension of the holder coupling (110) are fitted to the tip of the front module (108).

4. Modular sub-boom (100), according to claim 3, characterized by spacers (106) having the function of guide and dimensional guarantees to allow the exchange of the tip of module 108.

5. Modular sub-boom (100), according to claim 1, characterized in that the front module (102) can have its geometry altered for better adjustment to specific operating conditions and can also be replaced by removing only one weld joint (1 1 1).

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