Hot metal KR desulfurizer gravity feeding chute

Abstract

The invention discloses a gravity feeding chute for molten iron KR desulfurizer, comprising a feeding chute body, a feeding elbow, a feeding pipe, a compressed air pipe, a compressed air chamber and a compressed air nozzle; the upper port of the feeding elbow is welded and connected with the lower port of the feeding chute body; the feeding pipe is a tapered steel pipe, and the large port of the tapered steel pipe is welded and connected with the lower port of the feeding elbow; the upper port of the compressed air pipe is connected with a compressed air source; the compressed air chamber is an annular air chamber, arranged around the outer wall of the feeding pipe, and welded and connected with the lower port of the compressed air pipe; the compressed air nozzle is composed of a plurality of conical nozzles, which are uniformly distributed on the bottom surface of the compressed air chamber around the feeding pipe. The molten iron entrainment mixing amount of desulfurizers of different fine particle sizes and the desulfurization reaction interface area are increased, and finally the comprehensive purposes of reducing desulfurizer consumption, reducing desulfurizer feeding and escaping, shortening molten iron KR stirring time, stabilizing molten iron desulfurization effect, reducing slag iron loss and desulfurization molten iron temperature drop are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of molten iron pretreatment, and in particular to a molten iron KR desulfurizing agent gravity feeding chute. Background Art

[0002] The molten iron KR mechanical stirring desulfurization process uses a single-layer cross-arranged agitator with rectangular or inverted right-angled trapezoidal blades immersed in the molten iron to rotate and stir. The downward and inclined gravity feeding chute passes through the opening of the dust removal hood and extends into the above the stirring vortex liquid surface of the molten iron tank. The desulfurizer (generally composed of about 90% active lime and about 10% fluorite) is added to the liquid surface of the molten iron stirring vortex by gravity drive. The desulfurizer on the liquid surface is sucked and mixed by the molten iron stirring vortex to achieve desulfurization reaction at the interface between the desulfurizer and the molten iron. Therefore, it has excellent desulfurization reaction kinetics conditions and has become the preferred process for deep desulfurization of molten iron.

[0003] During the KR stirring desulfurization process of molten iron, the high temperature of the molten iron, which can reach nearly 1500℃, causes strong natural upward convection of air in the space above the molten iron surface. During the free fall of the desulfurizer gravity feeding, the strong natural convection upward airflow above the liquid surface carries the desulfurizer particles and fine powder to float and escape. Although the strong suction negative pressure of the dust removal exhaust port of the splash shield suppresses the desulfurizer from escaping and raising dust to the operating platform and causing environmental pollution, the dust removal and suction escape loss of the desulfurizer not only reduces the effective utilization rate of the desulfurizer and increases the consumption of the desulfurizer, but also increases the dust removal load and operating cost of the dust removal system. In order to reduce the amount of dust suction and escape during the desulfurization agent addition process, many companies, based on their own equipment conditions, have adopted the method of increasing the maximum critical size of desulfurizer particles and reducing the content of desulfurizer fine powder, so as to reduce the amount of desulfurizer airflow entrainment and escape, and increase the desulfurizer molten iron stirring and suction rate, so as to achieve the purpose of reducing desulfurizer consumption and dust environmental pollution. However, for the interface reaction form of lime particle surface contact in molten iron KR desulfurization, the increase of desulfurizer particles will lead to a sharp decrease in the specific surface area of ​​lime particles, a decrease in the effective utilization rate of desulfurizer, and an increase in desulfurizer consumption. This is also one of the main reasons for the significant differences in the particle size range and desulfurizer consumption of molten iron KR desulfurizers from different companies. For this reason, the smooth and stable addition technology of desulfurizer has received great attention from enterprises and scholars, and a technical solution for gas injection and addition of desulfurizer has been proposed. Through the acceleration of high-pressure carrier gas of desulfurizer, the injection speed and kinetic energy of desulfurizer are increased, the aggregation of desulfurizer is suppressed, and the ability to resist airflow entrainment and dispersion is enhanced, so as to achieve the comprehensive goals of reducing the particle size of desulfurizer, increasing the reaction area, and reducing the amount of dust removal and suction escape. However, the equipment transformation cost is high and the construction time of the transformation project is long, resulting in a large number of hot metal KR desulfurization stations still using the gravity feeding method of desulfurizer. It can be seen that how to reduce the dust emission and dust removal and suction escape in the process of gravity feeding of hot metal KR desulfurizer has become one of the important technical ways to reduce the consumption of desulfurizer, improve the technical and economic indicators of desulfurization, and achieve stable deep desulfurization of hot metal. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned technology and provide a gravity feeding chute for molten iron KR desulfurizer, which can reduce the escape rate of desulfurizer, increase the reaction specific surface area of ​​desulfurizer, promote the stirring, entrainment, mixing and dispersion of desulfurizer, and improve the desulfurization efficiency of molten iron, so as to achieve the comprehensive goals of improving the kinetic conditions of molten iron KR desulfurization reaction and the technical and economic indicators of molten iron desulfurization.

[0005] To achieve the above-mentioned purpose, the present invention provides a gravity feeding chute for molten iron KR desulfurizer, comprising a feeding chute body, a feeding elbow, a feeding pipe, a compressed air pipe, a compressed air chamber and a compressed air nozzle; the upper port of the feeding elbow is welded and connected with the lower port of the feeding chute body; the feeding pipe is a tapered steel pipe, and the large port of the tapered steel pipe is welded and connected with the lower port of the feeding elbow; the upper port of the compressed air pipe is connected with a compressed air source, and is welded and fixed to the feeding chute body and the feeding elbow in sections along the axial direction; the compressed air chamber is an annular chamber, which is arranged around the outer wall of the feeding pipe and is welded and connected with the lower port of the compressed air pipe; the compressed air nozzle is composed of a plurality of conical nozzles, which are evenly distributed on the bottom surface of the compressed air chamber around the feeding pipe.

[0006] Furthermore, the inner diameter of the feeding elbow is the same as the inner diameter of the feeding chute.

[0007] Furthermore, the cone angle α of the tapered steel pipe is 10° to 20°, the axis of the tapered steel pipe is perpendicular to the horizontal plane, the small end surface of the tapered steel pipe is a horizontal plane, and the inner diameter of the large end of the tapered steel pipe is the same as the inner diameter of the feeding elbow.

[0008] Furthermore, the compressed air pipe is made of a seamless steel pipe, and the inner diameter of the seamless steel pipe is 18 to 30 mm.

[0009] Furthermore, each of the conical nozzle axes is inclined downwardly toward the axis of the feeding pipe, and the angle β between the conical nozzle axis and the axis of the feeding pipe is 0° to α, and is fixedly connected to the bottom surface of the compressed air chamber.

[0010] Furthermore, the compressed air chamber is a steel pipe annular air chamber, the inner diameter of the steel pipe annular air chamber is 1 to 2 times the inner diameter of the compressed air pipe, and the inner ring surface is welded and fixed to the outer surface of the feeding pipe.

[0011] Furthermore, the compressed air chamber is a conical steel pipe annular air chamber, the cone angle of the conical steel pipe annular air chamber is the same as the cone angle of the feeding pipe, the conical steel pipe annular air chamber and the feeding pipe form a jacket, the gap width of the jacket is 5 to 15 mm, and it is prepared by full welding the upper and lower sealing ring steel plates with the feeding pipe and the conical steel pipe annular air chamber.

[0012] Furthermore, the number of the conical nozzles is 6 to 20, and the height difference between the center point of the conical nozzle outlet surface and the lower port surface of the conical steel pipe of the feeding pipe 3 is 5 to 15 mm.

[0013] Furthermore, the air flow jet speed of the compressed air nozzle is 50-120 m / s.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Compared with the circular straight tube of the existing gravity feeding chute, the iron molten KR desulfurizer gravity feeding chute of the present invention is designed with a structure consisting of a feeding chute body, a feeding elbow, a feeding pipe, a compressed air pipe, a compressed air chamber, and a compressed air nozzle. On the basis of the conventional gravity feeding chute, the feeding elbow, the feeding pipe, the compressed air pipe, the compressed air chamber, the compressed air nozzle and other components are organically combined to suppress the dust emission of the desulfurizer feeding. , and provide implementation conditions for improving the capture and entrainment rate of molten iron of desulfurizer; through the structural design of the feeding elbow, the change of the feeding direction of the desulfurizer in the conventional gravity feeding pipe is realized, the vertical feeding of the desulfurizer is ensured, the molten iron liquid surface impact penetration kinetic energy and the molten iron entrainment rate of the desulfurizer are improved, and the dust emission rate of the desulfurizer feeding is reduced; through the structural design of the conical feeding pipe, the cross-sectional area of ​​the gravity feeding flow of the desulfurizer is suppressed, the air entrainment and flow expansion speed of the feeding flow are delayed, and the rapid The uniformity and stability of the compressed air nozzle jet are ensured, and the shielding of the compressed air jet of the desulfurizer falling stream is realized, and the high-temperature natural convection in the upper space of the molten iron liquid surface is suppressed to entrain and rise the fine powder of the desulfurizer particles, reduce the dust emission of the desulfurizer desulfurization process, improve the capture and entrainment dynamics of the molten iron surface on the desulfurizer, and improve the desulfurizer entrainment and mixing utilization rate; the height difference between the center point of the nozzle outlet surface and the lower end surface of the conical steel pipe of the feeding pipe is set to 5-15mm, so as to avoid the wear of the desulfurizer particles on the nozzle, extend the service life of the nozzle, and improve the stability and reliability of the gravity feeding chute function of the molten iron KR desulfurizer.

[0016] From the above, it can be seen that compared with the prior art, the present invention improves the molten iron entrainment mixing amount of desulfurizers with different fine particle sizes and their desulfurization reaction interfacial area through the stable performance of the above-mentioned positive effects, and ultimately achieves the comprehensive purposes of reducing desulfurizer consumption, reducing the escape of desulfurizer feeding, shortening the molten iron KR stirring time, stabilizing the molten iron desulfurization effect, reducing slag removal iron loss and desulfurization molten iron temperature drop. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the gravity feeding chute of the molten iron KR desulfurizer of the present invention;

[0018] Figure 2 for Figure 1 Installation diagram of the use;

[0019] Figure 3 It is a schematic diagram of the feeding pipe and the steel pipe annular air chamber assembly;

[0020] Figure 4 It is a schematic diagram of the feeding pipe and the tapered steel pipe annular air chamber assembly;

[0021] Figure 5 for Figure 4 Schematic diagram of the top view.

[0022] The components in the figure are numbered as follows:

[0023] The feeding chute body 1, the feeding elbow 2, the feeding pipe 3, the compressed air pipe 4, the compressed air chamber 5, the steel pipe annular air chamber 5.1, the conical steel pipe annular air chamber 5.2, the compressed air nozzle 6, the discharge pipe 7, and the desulfurizer weighing tank 8. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clearer understanding of the present invention, but they do not constitute a limitation on the present invention.

[0025] like Figure 1 The molten iron KR desulfurizer gravity feeding chute shown in the figure includes a feeding chute body 1, a feeding elbow 2, a feeding pipe 3, a compressed air pipe 4, a compressed air chamber 5 and a compressed air nozzle 6. Figure 2The structure form, structure size and connection method of the feeding chute body 1 and the discharge pipe 7 of the desulfurizer weighing tank 8 are the same as those of the conventional gravity feeding chute; the feeding elbow 2 is made of commercially available arc steel pipe, the upper end of the feeding elbow 2 is welded and connected with the lower end of the feeding chute body 1, and the inner diameter of the feeding elbow 2 is the same as the inner diameter of the feeding chute 1; the feeding pipe 3 is a conical steel pipe, the cone angle α of the conical steel pipe is 10°~20°, the axis of the conical steel pipe is perpendicular to the horizontal plane, the large end of the conical steel pipe is welded and connected with the lower end of the feeding elbow 2, the small end surface of the conical steel pipe is a horizontal plane, and the inner diameter of the large end of the conical steel pipe is the same as the inner diameter of the feeding elbow 2; compressed air The tube 4 is made of seamless steel pipe with an inner diameter of 18 to 30 mm. The upper port is connected to the compressed air source and is welded and fixed to the feeding chute body 1 and the feeding elbow 2 in sections along the axial direction; the compressed air chamber 5 is an annular chamber, arranged around the outer wall of the feeding pipe 3, and is welded and connected to the lower port of the compressed air pipe 4; the compressed air nozzle 6 is composed of a plurality of conical nozzles, which are evenly distributed on the bottom surface of the compressed air chamber 5 around the feeding pipe 3, and the axis of each conical nozzle is inclined downward to the axis of the feeding pipe 3, and the angle β between the axis of the conical nozzle and the axis of the feeding pipe 3 is 0° to α, and is welded or threaded and fixed to the bottom surface of the compressed air chamber 5.

[0026] like Figure 3 , 4 The compressed air chamber 5 shown is a steel tube annular ring chamber 5.1 or a conical steel tube annular chamber 5.2, wherein the inner diameter of the steel tube annular ring chamber 5.1 is 1 to 2 times the inner diameter of the compressed air pipe 4, and the inner ring surface is welded and fixed to the outer surface of the feeding pipe 3; the cone angle of the conical steel tube annular chamber 5.2 is the same as the cone angle of the feeding pipe 3, and the conical steel tube annular chamber 5.2 and the feeding pipe 3 form a jacket, and the gap width of the jacket is 5 to 15 mm, and is prepared by full welding the upper and lower sealing ring steel plates with the feeding pipe and the conical steel tube annular chamber 5.2. Figure 5 The number of the conical nozzles shown is 6 to 20, and the height difference between the center point of the conical nozzle outlet surface and the lower end surface of the conical steel pipe of the feeding pipe 3 is 5 to 15 mm. The air flow injection speed of the compressed air nozzle 6 is 50 to 120 m / s.

[0027] The above-mentioned KR desulfurizer gravity feeding chute was used to replace the conventional feeding chute. An industrial test was carried out in a 300-ton hot metal tank KR stirring desulfurization station, and the desulfurizer consumption was reduced from 7.5Kg / t to 铁 Reduced to 6.4Kg / t 铁 The test effect.

Claims

1. A gravity feeding chute for molten iron KR desulfurizer, characterized in that: The invention comprises a feeding chute body (1), a feeding elbow (2), a feeding pipe (3), a compressed air pipe (4), a compressed air chamber (5) and a compressed air nozzle (6); the upper end of the feeding elbow (2) is welded and connected to the lower end of the feeding chute body (1); the feeding pipe (3) is a tapered steel pipe, and the large end of the tapered steel pipe is welded and connected to the lower end of the feeding elbow (2); the upper end of the compressed air pipe (4) is connected to a compressed air source, and is welded and fixed to the feeding chute body (1) and the feeding elbow (2) in sections along the axial direction; the compressed air chamber (5) is an annular air chamber, arranged around the outer wall of the feeding pipe (3), and is welded and connected to the lower end of the compressed air pipe (4); the compressed air nozzle (6) is composed of a plurality of conical nozzles, which are evenly distributed on the bottom surface of the compressed air chamber (5) around the feeding pipe (3); The cone angle α of the conical steel pipe is 10° to 20°, the axis of the conical steel pipe is perpendicular to the horizontal plane, the small end surface of the conical steel pipe is a horizontal plane, and the inner diameter of the large end of the conical steel pipe is the same as the inner diameter of the feeding elbow (2); the axis of each conical nozzle is inclined downward to the axis of the feeding pipe (3) and is arranged obliquely, and the angle β between the axis of the conical nozzle and the axis of the feeding pipe (3) is 0° to α, and is fixedly connected to the bottom surface of the compressed air chamber (5).

2. The molten iron KR desulfurizer gravity feeding chute according to claim 1 is characterized in that: The inner diameter of the feeding elbow (2) is the same as the inner diameter of the feeding chute body (1).

3. The molten iron KR desulfurizer gravity feeding chute according to claim 1 is characterized in that: The compressed air pipe (4) is made of a seamless steel pipe, and the inner diameter of the seamless steel pipe is 18 to 30 mm.

4. The molten iron KR desulfurizer gravity feeding chute according to claim 1 is characterized in that: The compressed air chamber (5) is a steel pipe annular ring-shaped chamber (5.1), the inner diameter of which is 1 to 2 times the inner diameter of the compressed air pipe (4), and the inner ring surface is fixedly welded to the outer surface of the feeding pipe (3).

5. The molten iron KR desulfurizer gravity feeding chute according to claim 1 is characterized in that: The compressed air chamber (5) is a conical steel tube annular chamber (5.2), the cone angle of the conical steel tube annular chamber (5.2) is the same as the cone angle of the feeding pipe (3), the conical steel tube annular chamber (5.2) and the feeding pipe (3) form a jacket, the gap width of the jacket is 5 to 15 mm, and is prepared by full welding the upper and lower sealing ring steel plates with the feeding pipe (3) and the conical steel tube annular chamber (5.2).

6. The molten iron KR desulfurizer gravity feeding chute according to claim 1, characterized in that: The number of the conical nozzles is 6 to 20, and the height difference between the center point of the conical nozzle outlet surface and the lower port surface of the feeding pipe (3) is 5 to 15 mm.

7. The molten iron KR desulfurizer gravity feeding chute according to claim 1 is characterized in that: The air flow jet speed of the compressed air nozzle (6) is 50 to 120 m / s.

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