CN207738801U - A kind of dual channel design RH refining furnace top blast nozzles - Google Patents

Abstract

The utility model relates to a double-channel design RH refining furnace top blowing nozzle, which belongs to the technical field of RH refining. Including central oxygen channel, auxiliary oxygen channel, auxiliary oxygen hole, main oxygen hole, sixth layer tube, fifth layer tube, fourth layer tube, third layer tube, second layer tube, central oxygen tube; central oxygen tube jacket There is a second layer of tubes, the second layer of tubes is covered with a third layer of tubes, the third layer of tubes is covered with a fourth layer of tubes, the central oxygen channel and the auxiliary oxygen channel are connected to the two flow channel interfaces, and the fourth layer of tubes is covered with The fifth layer of pipe, the fifth layer of pipe is covered with the sixth layer of pipe, the main oxygen channel water inlet channel of the central oxygen channel is connected with the main oxygen channel outlet water channel, the auxiliary oxygen channel water inlet channel of the auxiliary oxygen channel is connected with the auxiliary oxygen channel outlet water The channels are connected, and the layers of pipes are connected by welding. The advantage is that the designed double-channel top-blowing nozzle can increase the secondary combustion rate to 70-75%, which greatly improves the utilization efficiency of heat in the RH furnace.

Description

A double-channel design RH refining furnace top blowing nozzle

technical field

The utility model belongs to the technical field of RH refining, and in particular relates to a top blowing head of an RH refining furnace with a double-channel design, which is suitable for the vacuum decarburization process of the RH refining furnace.

Background technique

In the mid-1980s, Japan developed the RH vacuum decarburization technology. Since then, RH refining of high-purity thin-plate steel has entered a new stage. By the beginning of the 21st century, there were 165 sets of RH equipment in the world, including 46 sets of OB type, 36 sets of KTB type, and other RH processing equipment such as IJ type, PB, MFB, etc., but the above two types accounted for the main proportion.

RH-OB installs an oxygen blowing nozzle on the bottom side wall of the vacuum chamber of the molten steel vacuum circulation degassing device, and blows oxygen to the molten steel in the vacuum chamber to remove carbon in the molten steel. This method can make the carbon in the molten steel treated by RH reach 0.002 %s level. In 1972, Nippon Steel Muroran Iron Works developed the RH-OB and converter matching technology, and successfully produced chromium-containing stainless steel. Immediately afterwards, Nippon Steel Oita Steel Works developed the RH-OB vacuum refining process technology on the basis of it, using the converter, RH-OB vacuum oxygen blowing method for forced decarburization, adding aluminum and oxygen blowing to increase the temperature of molten steel, and producing Aluminum killed steel and other technologies have reduced the burden on the converter, achieved the purpose of carbon tapping at the fixed end point of the converter, improved the operation rate of the converter, and reduced the consumption of deoxidized aluminum. RH-OB vacuum oxygen blowing technology exposed its own weaknesses while developing and hindered its further development, mainly reflected in the limited life of RH-OB nozzles, reducing the operating rate of RH equipment; serious splashing, increasing the RH vacuum Nodulation and auxiliary operation time in the chamber; higher RH vacuum pump capacity is required.

The RH-KTB device is a new technology developed in 1988 by the Kawasaki Iron and Steel Institute of Japan on the basis of the RH vacuum refining method to improve the vacuum decarburization rate of smelting ultra-low carbon steel. Use the KTB gun to blow oxygen into the molten pool from above the liquid surface of the RH vacuum chamber at a supersonic flow, a part of the oxygen reacts with [C] in the molten steel to form CO, and a part of the oxygen dissolves into the molten steel to form dissolved oxygen and [C] in the molten steel C] reaction realizes the deep decarburization treatment by using _O2 when [O] is insufficient relative to [C] in the high-carbon area, which speeds up the decarburization reaction speed and reduces [C] to a lower level. The rising CO can react with part of the O ₂ ejected from the KTB gun, generate CO ₂ after secondary combustion, and release a certain amount of chemical heat. According to literature reports, the secondary combustion rate of RH-KTB is about 40-60%, and the temperature compensation can reduce the tapping temperature of the converter by 20-26°C.

In order to further develop the advantages of the secondary combustion technology in the RH refining furnace, it is necessary to develop a secondary combustion oxygen lance suitable for the RH refining furnace by referring to the characteristics of the secondary combustion reaction in the converter or electric furnace. By analyzing the characteristics of the RH-KTB top-blown spray gun, etc., while maintaining the advantages of the top-blown spray gun, the RH-KTB spray gun nozzle has both the main oxygen jet and the auxiliary oxygen jet. The main oxygen jet is mainly used to promote the decarburization of molten steel And part of the temperature rise, the oxygen ejected from the auxiliary oxygen hole can further fully react with the CO gas rising from the molten pool, and promote the increase of the secondary combustion rate in the RH furnace.

The use of the RH top-blown oxygen special secondary combustion spray gun with the above functions will not only ensure the rapid decarburization technology under the original conditions, but also fully improve the thermal efficiency of the furnace, and make the molten steel cool down during the vacuum treatment process. In this way, the tapping temperature of the converter can be further reduced and the carbon content at the end of tapping can be increased, so that the processing cost of the converter can be reduced again, and at the same time, the bonding of cold steel in the RH vacuum chamber can be reduced to prevent nodules.

Contents of the invention

The purpose of this utility model is to provide a double-channel design RH refining furnace top blowing nozzle, through which the secondary combustion in the RH refining furnace can be further promoted and the efficiency can be improved.

The utility model comprises a central oxygen channel 1, an auxiliary oxygen channel 2, an auxiliary oxygen channel water inlet channel 3 (between the fourth layer pipe 11 and the fifth layer pipe 10), an auxiliary oxygen channel water outlet channel 4 (the fifth layer pipe 10 and Between the sixth layer of pipes 9), auxiliary oxygen holes 5, main oxygen channel water inlet channel 6 (between the central oxygen tube 14 and the second layer of pipe 13), main oxygen channel water outlet channel 7 (the second layer of pipe 13 and the second layer of pipe 13) between the three-layer pipes 12), the main oxygen hole 8, the sixth-layer pipe 9, the fifth-layer pipe 10, the fourth-layer pipe 11, the third-layer pipe 12, the second-layer pipe 13, and the central oxygen pipe 14. The central oxygen pipe 14 is covered with a second layer of pipe 13, the main oxygen channel water inlet channel 6 is formed between the central oxygen pipe 14 and the second layer of pipe 13, the second layer of pipe 13 is covered with a third layer of pipe 12, the second layer of pipe 13 and the third layer of pipe 12 form the main oxygen channel outlet channel 7, the third layer of pipe 12 is covered with the fourth layer of pipe 11, the third layer of pipe 12 and the fourth layer of pipe 11 form the auxiliary oxygen channel 2, the center The oxygen channel 1 and the auxiliary oxygen channel 2 are connected to the two flow channel interfaces, the fourth layer tube 11 is covered with the fifth layer tube 10, and the auxiliary oxygen channel water inlet channel is formed between the fourth layer tube 11 and the fifth layer tube 10 3. The fifth layer of pipe 10 is covered with the sixth layer of pipe 9, the secondary oxygen channel outlet channel 4 is formed between the fifth layer of tube 10 and the sixth layer of tube 9, and the main oxygen channel water inlet channel 6 of the central oxygen channel 1 is connected to the main oxygen channel. The outlet water channel 7 of the oxygen channel is connected, the water inlet channel 3 of the auxiliary oxygen channel 2 is connected with the water outlet channel 4 of the auxiliary oxygen channel, and the pipes of each layer are connected by welding. The main oxygen hole 8 is mainly used to generate high-speed oxygen jet flow and decarburization reaction with the ladle molten pool. It can also inject desulfurizer for desulfurization according to the needs. The auxiliary oxygen hole 5 can form a secondary combustion reaction with the rising gas of CO to form a secondary combustion reaction to the molten pool. The molten steel is temperature compensated to reduce the temperature drop during vacuum treatment.

The main oxygen hole 2 is designed as a vertical single hole or symmetrically arranged on the same horizontal circle as a porous center. The angle between the hole and the vertical direction is between 12° and 18°.

The main oxygen hole of the top blowing nozzle is a Laval supersonic nozzle, the outlet Mach number is 1.9-2.1, the diameter of the throat is calculated according to the oxygen consumption, and the nozzle hole spacing of the porous main oxygen hole is 1.0-1.4 times the outlet of the nozzle hole diameter.

The auxiliary oxygen holes are designed as constant-velocity straight pipes and are symmetrically arranged on the same horizontal circumference. According to the weight of molten steel in the ladle, there are 6 to 12 holes, and the included angle between the auxiliary oxygen holes and the vertical direction is 30~ between 45°.

The auxiliary oxygen holes are designed with double channels and double layers, and the vertical distance from the inlet of the auxiliary oxygen holes to the inlet of the main oxygen holes is between 100 mm and 300 mm.

In terms of oxygen distribution, oxygen mainly flows through the main oxygen holes, and the auxiliary oxygen holes account for 10-20% of the total oxygen consumption.

The main oxygen hole can realize the function of top-blowing powder injection, and the desulfurization powder is sprayed to the liquid surface of the molten pool through the main oxygen hole to achieve a further desulfurization effect.

The main oxygen hole is mainly used to provide _O2 and make the high-speed jet generated by the Laval nozzle react with carbon and oxygen in the ladle molten pool. The dual-channel auxiliary oxygen holes symmetrically distributed at a certain distance above the nozzle of the main oxygen hole can provide the total gas volume. 10-20% _O2 reacts with carbon and oxygen in the molten pool to fully form the CO rising gas to form a secondary combustion reaction, so that the temperature compensation of the ladle molten pool can be further performed. The main oxygen hole adopts a porous symmetrical design. The porous nozzle can increase the reaction interface area, and can also increase the top blowing powder injection function. The powder is evenly sprayed to the liquid surface of the molten pool through the main oxygen hole to achieve the desulfurization effect. The dual-channel top-blowing nozzle designed by the utility model can increase the secondary combustion rate to 70-75%, and greatly improves the utilization efficiency of heat in the RH furnace.

The beneficial effects of the utility model are as follows:

(1) During the vacuum decarburization process, the secondary combustion oxygen lance promotes the full secondary combustion of CO gas, which compensates for the decrease in the temperature of molten steel in the furnace and reduces the cooling rate of molten steel during vacuum treatment.

(2) The lower part of the vacuum chamber is fully heated by the secondary combustion oxygen lance, and the splashed steel droplets are not easy to adhere to the wall, which effectively inhibits the adhesion of residual steel in the vacuum chamber and avoids excessive erosion of the vacuum chamber.

(3) The main oxygen hole with porous arrangement can increase the function of top-blowing powder injection, and the desulfurization powder can be evenly sprayed to the liquid surface of the molten pool through the main oxygen hole to achieve the desulfurization effect.

Description of drawings

Fig. 1 is a schematic front view of the top blowing nozzle of the RH refining furnace with a double-channel design under the single-hole main oxygen hole of the utility model.

Fig. 2 is a top view schematic diagram of the double-channel design RH refining furnace roof blowing nozzle under the single-hole main oxygen hole of the present invention.

Fig. 3 is a schematic front view of the double-channel design RH refining furnace top blowing nozzle under the multi-hole main oxygen hole of the utility model.

Fig. 4 is a schematic diagram of a top-down test of the double-channel design RH refining furnace roof blowing nozzle under the porous main oxygen hole of the present invention.

In the figure: central oxygen channel 1, auxiliary oxygen channel 2, auxiliary oxygen channel water inlet channel 3, auxiliary oxygen channel outlet channel 4, auxiliary oxygen hole 5, main oxygen channel water inlet channel 6, main oxygen channel outlet channel 7, main oxygen channel Hole 8, sixth layer tube 9, fifth layer tube 10, fourth layer tube 11, third layer tube 12, second layer tube 13, central oxygen tube 14.

Detailed ways

Below in conjunction with above-mentioned accompanying drawing, the use of the present utility model is further described.

The utility model includes a central oxygen channel 1, an auxiliary oxygen channel 2, an auxiliary oxygen channel water inlet channel 3, an auxiliary oxygen channel water outlet channel 4, an auxiliary oxygen hole 5, a main oxygen channel water inlet channel 6, a main oxygen channel water outlet channel 7, and a main oxygen channel. Oxygen hole 8, sixth layer pipe 9, fifth layer pipe 10, fourth layer pipe 11, third layer pipe 12, second layer pipe 13, central oxygen pipe 14. The central oxygen pipe 14 is covered with a second layer of pipe 13, the main oxygen channel water inlet channel 6 is formed between the central oxygen pipe 14 and the second layer of pipe 13, the second layer of pipe 13 is covered with a third layer of pipe 12, the second layer of pipe 13 and the third layer of pipe 12 form the main oxygen channel outlet channel 7, the third layer of pipe 12 is covered with the fourth layer of pipe 11, the third layer of pipe 12 and the fourth layer of pipe 11 form the auxiliary oxygen channel 2, the center The oxygen channel 1 and the auxiliary oxygen channel 2 are connected to the two flow channel interfaces, the fourth layer tube 11 is covered with the fifth layer tube 10, and the auxiliary oxygen channel water inlet channel is formed between the fourth layer tube 11 and the fifth layer tube 10 3. The fifth layer of pipe 10 is covered with the sixth layer of pipe 9, the secondary oxygen channel outlet channel 4 is formed between the fifth layer of tube 10 and the sixth layer of tube 9, and the main oxygen channel water inlet channel 6 of the central oxygen channel 1 is connected to the main oxygen channel. The outlet water channel 7 of the oxygen channel is connected, the water inlet channel 3 of the auxiliary oxygen channel 2 is connected with the water outlet channel 4 of the auxiliary oxygen channel, and the pipes of each layer are connected by welding. The main oxygen hole 8 is mainly used to generate high-speed oxygen jet flow and decarburization reaction with the ladle molten pool. It can also inject desulfurizer for desulfurization according to the needs. The auxiliary oxygen hole 5 can form a secondary combustion reaction with the rising gas of CO to form a secondary combustion reaction to the molten pool. The molten steel is temperature compensated to reduce the temperature drop during vacuum treatment.

Figures 1 to 4 show two implementations of the double-channel design of the top blowing nozzle of the RH refining furnace. The oxygen sprayed by the nozzle is divided into two parts, one part of oxygen is sprayed from the main oxygen hole, and the other is sprayed from the auxiliary oxygen hole. Due to the dual flow channel design of the nozzle, the oxygen flow of the main oxygen channel and the auxiliary oxygen channel can be controlled separately According to the actual situation, select the appropriate flow range, but the auxiliary oxygen flow should not be too large or too small. Generally, the auxiliary oxygen flow accounts for 10-20% of the overall oxygen supply. The oxygen flow in the main oxygen channel passes through the Laval nozzle of the main oxygen hole, and is accelerated into a supersonic airflow rushing to the liquid steel surface. According to the difference in the weight of the molten steel being processed between 50 and 300t, the main oxygen hole of the top blowing nozzle is set as a single Holes or 3 to 6 main oxygen holes can achieve full contact and reaction between oxygen jet and molten steel. The oxygen flow in the auxiliary oxygen channel passes through the metal straight pipe to maintain a certain subsonic speed and enters the RH vacuum chamber, where it is fully combusted with the rising CO gas. In order to make full use of the rising CO gas in the vacuum chamber, the outlet height of the auxiliary oxygen hole is specially set at a distance of 100-300mm above the outlet position of the main oxygen hole, and the weight of molten steel is also between 50-300t according to the difference , setting 6 to 12 symmetrically distributed sub-oxygen holes can fully improve the reaction efficiency of different sizes of space. The spray gun connected to the top-blowing nozzle starts the top-blowing deep decarburization function during the vacuuming process. During the process of processing a certain 300t molten steel in the RH refining furnace, when the oxygen blowing time of the top-blowing nozzle is about 5 minutes, the oxygen in the RH refining furnace can be made The secondary combustion rate is increased to 70-75%. In addition, when performing top-blown powder injection, the auxiliary oxygen channel must be closed at this time, and the desulfurization powder enters the ladle liquid surface through the main oxygen hole to carry out deep desulfurization reaction.

In summary, the embodiment of the utility model provides a double-channel design RH refining furnace top blowing nozzle, by using the utility model device, the secondary combustion rate in the RH refining furnace can be increased to 70-75%, reaching The compensation effect of the molten steel temperature in the RH refining furnace is improved, and the cooling rate of the molten steel in the vacuum treatment process is reduced. In addition, the sufficient heating of the secondary combustion makes it difficult for the splashed steel droplets to adhere to the furnace wall of the vacuum chamber, which effectively inhibits the adhesion of residual steel in the vacuum chamber and avoids excessive erosion of the vacuum chamber.

Claims (5)

1. A double-channel design RH refining furnace roof blowing nozzle is characterized in that it includes a central oxygen channel (1), an auxiliary oxygen channel (2), an auxiliary oxygen hole (5), a main oxygen hole (8), and a sixth layer Pipe (9), fifth layer pipe (10), fourth layer pipe (11), third layer pipe (12), second layer pipe (13), central oxygen pipe (14); central oxygen pipe (14) There is a second layer of pipe (13) in the jacket, the main oxygen channel water inlet channel (6) is formed between the central oxygen pipe (14) and the second layer of pipe (13), and the second layer of pipe (13) is covered with a third layer of pipe (12), the main oxygen channel outlet channel (7) is formed between the second layer of pipe (13) and the third layer of pipe (12), the third layer of pipe (12) is covered with a fourth layer of pipe (11), the third A secondary oxygen channel (2) is formed between the layer tube (12) and the fourth layer tube (11), the central oxygen channel (1) and the secondary oxygen channel (2) are connected with the two flow channel interfaces, and the fourth layer tube ( 11) There is a fifth layer of pipe (10) in the outer jacket, and the auxiliary oxygen channel water inlet channel (3) is formed between the fourth layer of pipe (11) and the fifth layer of pipe (10), and the fifth layer of pipe (10) is covered with the first The six-layer pipe (9), the secondary oxygen channel outlet channel (4) is formed between the fifth-layer tube (10) and the sixth-layer tube (9), and the main oxygen channel water inlet channel (6) of the central oxygen channel (1) It is connected with the water outlet channel (7) of the main oxygen channel, the water inlet channel (3) of the auxiliary oxygen channel (2) is connected with the water outlet channel (4) of the auxiliary oxygen channel, and the pipes of each layer are connected by welding. 2. The double-channel design RH refining furnace top blowing head according to claim 1, characterized in that: the main oxygen hole (8) is designed as a vertical single hole or a porous center symmetrically arranged on the same horizontal circle, and the porous The number of main oxygen holes is designed to be between 3 and 6, and the included angle between the main oxygen holes and the vertical direction is between 12° and 18°. 3. The double-channel design RH refining furnace top blowing nozzle according to claim 1, characterized in that: the main oxygen hole (8) is a Laval supersonic nozzle, the outlet Mach number is 1.9-2.1, and the porous main oxygen The orifice spacing of the holes is 1.0 to 1.4 times the diameter of the exit of the orifice. 4. The double-channel design RH refining furnace top blowing nozzle according to claim 1, characterized in that: the auxiliary oxygen holes (5) are designed as constant-velocity straight pipes and are symmetrically arranged on the same horizontal circumference. The difference in weight of the molten steel is between 6 and 12, and the included angle between the auxiliary oxygen holes (5) and the vertical direction is between 30 and 45°. 5. The double-channel design RH refining furnace top blowing nozzle according to claim 1, characterized in that: the auxiliary oxygen hole (5) is a double-layer design with double flow channels, and the vertical distance from the outlet of the auxiliary oxygen hole to the outlet of the main oxygen hole is 100 ~300mm.