A swirl supersonic secondary combustion oxygen lance

Abstract

The present application relates to a kind of swirl supersonic secondary combustion oxygen lance, including lance body and spray head, lance body includes center oxygen pipe, cooling inlet water layer and cooling outlet water layer from inside to outside in turn, spray head is connected the front end of lance body, several main oxygen flow channels and several auxiliary oxygen flow channels are uniformly arranged in spray head inside;The tail of main oxygen flow channel and auxiliary oxygen flow channel is communicated center oxygen pipe, for oxygen supply;The head of main oxygen flow channel forms main oxygen jet orifice at the front end surface of spray head, and several main oxygen jet orifices are arranged in circle;The head of auxiliary oxygen flow channel forms auxiliary oxygen jet orifice at spray head side;Main oxygen flow channel and auxiliary oxygen flow channel are all Laval type, can form supersonic oxygen jet;The outside of main oxygen flow channel and auxiliary oxygen flow channel is equipped with sleeve layer, and several hollow flow guide ribs are uniformly arranged in cooling inlet water layer, and flow guide rib is communicated with the sleeve layer, and input heat preservation gas for sleeve layer;Cooling inlet water layer, cooling outlet water layer are communicated with spray head inside, and input, output cooling water for spray head.

Description

Technical Field

[0001] This invention belongs to the field of secondary combustion oxygen lance technology, specifically relating to a swirling supersonic secondary combustion oxygen lance. Background Technology

[0002] In the metallurgical field, especially in converter steelmaking and molten reduction ironmaking, secondary combustion oxygen lances are key equipment for achieving secondary CO combustion in the furnace, supplementing heat, and improving energy utilization. Existing secondary combustion oxygen lances suffer from low efficiency, short lifespan, and complex structure. Currently, the main structure of a secondary combustion oxygen lance consists of a main oxygen pipe connected to a nozzle, a main oxygen orifice in the center of the nozzle, and several auxiliary oxygen orifices on the side of the nozzle or around the main oxygen orifice. One end of the main and auxiliary oxygen orifices connects to the main oxygen pipe, and the other end connects to the external environment of the nozzle, supplying oxygen to the furnace through these orifices. In patent CN114196798B, the auxiliary oxygen orifices are vertically located on the sidewall of the nozzle, not occupying the main space of the nozzle. The auxiliary oxygen is taken from the high-speed jet zone of the main oxygen, resulting in large pressure fluctuations. Furthermore, the combustion zone formed by the vertical outlet is dispersed, easily impacting the furnace lining. Over long-term service, the nozzle sidewall faces challenges in fatigue resistance and corrosion resistance. Additionally, the main and auxiliary oxygen orifices are in direct contact with cooling water, causing the supplied oxygen to be cooled, resulting in a slightly lower temperature when it enters the furnace, which is not conducive to the complete combustion of CO in the furnace. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a swirling supersonic secondary combustion oxygen lance, comprising a lance body and a nozzle. The lance body, from the inside out, includes a central oxygen tube, a cooling water inlet layer, and a cooling water outlet layer. The nozzle is connected to the front end of the lance body, and the nozzle interior is uniformly arranged with several main oxygen channels and several secondary oxygen channels. The tail ends of both the main and secondary oxygen channels are connected to the central oxygen tube for oxygen supply. The head of the main oxygen channel forms a main oxygen nozzle on the front end face of the nozzle, and several main oxygen nozzles are arranged in a ring. The head of the secondary oxygen channels forms secondary oxygen nozzles on the side of the nozzle. Both the main and secondary oxygen channels are Laval type, capable of forming a supersonic oxygen jet.

[0004] Both the main oxygen flow channel and the auxiliary oxygen flow channel are equipped with a sleeve on the outside. Several hollow guide ribs are evenly arranged in the cooling water inlet layer. The guide ribs are connected to the sleeve to input heat-insulating gas into the sleeve. The cooling water inlet layer and the cooling water outlet layer are both connected to the inside of the nozzle to input and output cooling water into the nozzle.

[0005] The nozzle end face of the present invention is provided with a main oxygen nozzle to spray oxygen in front of the oxygen lance, and a secondary oxygen nozzle is provided on the side of the nozzle to form a tangential layout, which sprays oxygen outward to the side of the nozzle, avoiding mutual "entrapment" between the main and secondary oxygen nozzles, ensuring that heat is evenly transferred to the molten pool and reducing the consumption of heat-replenishing agent.

[0006] Cooling water from the cooling water inlet layer is introduced into the nozzle to cool it. The area outside the nozzle is the high-temperature environment of the furnace, while the inside is the cooling water environment, resulting in significant thermal shock. The nozzle's outer wall is connected to the lance body, and the nozzle itself has high strength to withstand this thermal shock. However, the main and auxiliary oxygen channels are suspended inside the nozzle. One end of each channel is connected to the central oxygen pipe of the lance body, and the other end is connected to the nozzle's end face or side. This means one end is in a cold environment, and the other end is in an extremely hot environment. The walls of the main and auxiliary oxygen channels are subjected to this significant temperature difference, posing a considerable challenge to the channel materials.

[0007] To address the aforementioned problems, this invention incorporates a sleeve on the outer side of both the main and auxiliary oxygen channels. This sleeve allows for the introduction of insulating gas, separating the oxygen inside the channels from the external cooling water. This not only prevents the oxygen inside the channels from being cooled and reducing combustion efficiency after spraying, but also maintains a relatively low temperature on the walls of the main and auxiliary oxygen channels, preventing excessive temperature differences between different parts of the channel walls. This effectively protects the channel walls and extends the nozzle's service life.

[0008] Optionally, the gun body is cylindrical, with the central oxygen pipe, cooling water inlet layer, and cooling water outlet layer all concentrically arranged. The tail end of the central oxygen pipe is connected to an oxygen supply device to supply oxygen to the central oxygen pipe and the connected main and auxiliary oxygen channels. The tail end of the cooling water inlet layer is connected to a water supply device for inputting cooling water. The tail end of the cooling water outlet layer is also connected to a water supply device for outputting cooling water. The water supply device is a water chiller with a circulation function.

[0009] The front of the gun body is open, and the rear of the nozzle is also open. The gun body and the nozzle are welded together.

[0010] Optionally, the cross-section of the gun body includes, from the inside to the outside, a central oxygen pipe wall, an outer wall of the cooling water inlet layer, and an outer wall of the cooling water outlet layer. The cross-section of the rear part of the nozzle is also provided with concentric inner and outer three layers of pipe walls, namely the first pipe wall, the second pipe wall, and the third pipe wall, which are respectively welded to the central oxygen pipe wall, the outer wall of the cooling water inlet layer, and the outer wall of the cooling water outlet layer, so that the gun body and the nozzle form an integral whole.

[0011] Optionally, the nozzle is cylindrical in shape, and the front end face of the nozzle is a conical surface with the center protruding forward; the front end of the first pipe wall is closed and is a conical surface with the center protruding forward, and the tail ends of all main oxygen channels are connected to the conical surface of the first pipe wall (i.e. the front end face of the first pipe wall) and communicate with the internal space of the first pipe wall, so that the main oxygen channels are connected to the central oxygen pipe.

[0012] The front end of the second pipe wall is provided with several water distribution plates, which are evenly distributed along the circumference of the second pipe wall to guide the cooling water input into the cooling water inlet layer to be distributed radially along the nozzle; the front end of the third pipe wall is closed by the front end face of the nozzle, which introduces the water in the nozzle into the cooling water outlet layer and then discharges it.

[0013] Optionally, the plurality of main oxygen nozzles are evenly distributed along the circumference of the nozzle, with 3-6 main oxygen nozzles, and the main oxygen flow channel is a standard Laval nozzle with a conical angle of 30-40° in the contraction section, a throat diameter of 30-60 mm, a conical angle of 12-16° in the expansion section, and an exit Mach number of 2.0-2.4; the angle between the central axis of the main oxygen flow channel and the central axis of the nozzle body is 12-16°.

[0014] Further optionally, the auxiliary oxygen flow channel passes through the three layers of pipe wall on the side of the nozzle, and several auxiliary oxygen flow channels are evenly distributed along the circumference of the third pipe wall; there are 4-12 auxiliary oxygen nozzles, and the centers of the main and auxiliary oxygen nozzles are not on the same radial straight line of the nozzle, so as to realize the circumferential staggered arrangement of the main and auxiliary oxygen nozzles and avoid jet interference.

[0015] The secondary oxygen channel is a standard Laval nozzle, with a converging section cone angle of 10-35°, a throat diameter of 6-20mm, an expanding section cone angle of 6-12°, and an exit Mach number of 1.2; the central axis of the main and secondary oxygen channels is perpendicular to the central axis of the nozzle body.

[0016] Further optionally, the number of main oxygen channels is less than the number of auxiliary oxygen channels, with 2-4 auxiliary oxygen channels corresponding to one main oxygen channel.

[0017] Alternatively, one of the two intersections between the central axis of the auxiliary oxygen channel and the outer wall of the gun body, the intersection furthest from the auxiliary oxygen channel, can be selected as the reference point. The central axis of the gun body in the width direction passing through the reference point can be selected as the reference axis. The angle between the reference axis and the central axis of the auxiliary oxygen channel is 25-45°, so that the auxiliary oxygen jet forms a stable downward swirling flow, expands the spreading area, enhances mixing with CO, and avoids key areas of the furnace lining.

[0018] The sum of the flow rates of all auxiliary oxygen channels accounts for 8-25% of the total oxygen supply of the central oxygen tube.

[0019] Optionally, a number of inlet guide ribs and a number of outlet guide ribs are provided on the outer surface of the central oxygen pipe, which are respectively for inputting and outputting heat-insulating gas for each layer. The inlet guide ribs and outlet guide ribs are alternately arranged and evenly distributed along the circumference of the central oxygen pipe.

[0020] The inlet guide rib is wavy, and the outlet guide rib is straight. The centerline of the inlet guide rib, the outlet guide rib and the center axis of the central oxygen pipe are parallel to each other. The inlet guide rib corresponds one-to-one with the sleeve of the auxiliary oxygen flow channel, and the outlet guide rib corresponds one-to-one with the sleeve of the main oxygen flow channel.

[0021] Further optional, the tails of each air intake guide rib are connected in parallel and pass through the gun body, and then connected to the air supply device; the head of the air intake guide rib extends along the outer side of the first pipe wall into the nozzle, and then connects to the sleeve of each secondary oxygen channel, and then the sleeve of the secondary oxygen channel is connected to the sleeve of the adjacent main oxygen channel through the connecting guide rib.

[0022] The main oxygen flow channel is connected to the head of the outlet guide rib. The outlet guide rib extends along the front end and outer side of the first pipe wall to form a nozzle. The tails of each outlet guide rib are connected in parallel and pass through the gun body, and then connect to the exhaust pipe.

[0023] Optionally, the sleeve is a cylinder, fitted over the outside of the main oxygen flow channel or the auxiliary oxygen flow channel, with a gap between it and the main oxygen flow channel or the auxiliary oxygen flow channel to allow the insulation gas to pass through;

[0024] The central axis of the sleeve of the auxiliary oxygen flow channel is perpendicular to the central axis of the gun body. The two ends of the sleeve of the auxiliary oxygen flow channel are welded to the outer side of the first pipe wall and the inner side of the third pipe wall, respectively. The sleeve of the auxiliary oxygen flow channel is welded at the position where it penetrates the second pipe wall.

[0025] The central axis of the sleeve of the main oxygen flow channel is parallel to the central axis of the corresponding main oxygen flow channel. The two ends of the sleeve of the main oxygen flow channel are welded to the front end face of the first pipe wall and the front end face of the nozzle, respectively.

[0026] Further optionally, the height of the intake guide rib is 3-5mm, and the vertical distance between the center line of the intake guide rib and its own peak and trough is equal and is 5-8mm.

[0027] Because the number of main and auxiliary oxygen flow channels differs, several inlet guide ribs are connected in parallel to correspond to one outlet guide rib. Based on the ratio of the number of corresponding inlet and outlet guide ribs, the sum of the cross-sectional areas of the inlet guide ribs equals the cross-sectional area of ​​the corresponding outlet guide rib. The cross-sectional dimensions of the inlet and outlet guide ribs, as well as the spacing between adjacent inlet and outlet guide ribs, are also set according to the actual situation. Attached Figure Description

[0028] Figure 1 A schematic diagram of a swirling supersonic secondary combustion oxygen lance (I);

[0029] Figure 2 A schematic diagram of a swirling supersonic secondary combustion oxygen lance (II);

[0030] Figure 3 A schematic diagram of the main oxygen flow channel;

[0031] Figure 4 This is a schematic diagram of the auxiliary oxygen flow channel;

[0032] Figure 5A schematic diagram of the inlet and outlet guide ribs on the outer wall of the central oxygen tube;

[0033] Figure 6 This is a schematic diagram showing the angle between the reference axis and the central axis of the secondary oxygen flow channel.

[0034] Among them, 1-gun body, 2-nozzle, 3-central oxygen pipe, 4-cooling water inlet layer, 5-cooling water outlet layer, 6-main oxygen flow channel, 7-secondary oxygen flow channel, 8-sheath, 9-first pipe wall, 10-second pipe wall, 11-third pipe wall, 12-water distribution plate, 13-reference point, 14-reference axis, 15-air inlet guide rib, 16-air outlet guide rib, 17-connecting guide rib. Detailed Implementation

[0035] Example 1

[0036] This embodiment provides a swirling supersonic secondary combustion oxygen lance, such as Figures 1-6 As shown, the device includes a gun body 1 and a nozzle 2. The gun body 1 includes, from the inside out, a central oxygen pipe 3, a cooling water inlet layer 4, and a cooling water outlet layer 5. The nozzle 2 is connected to the front end of the gun body 1. The nozzle 2 has three main oxygen channels 6 and six secondary oxygen channels 7 evenly arranged inside. The tail ends of the main and secondary oxygen channels are connected to the central oxygen pipe 3 for oxygen supply. The head of the main oxygen channel 6 forms a main oxygen nozzle on the front end face of the nozzle 2, and the three main oxygen nozzles are arranged in a circle. The head of the secondary oxygen channel 7 forms a secondary oxygen nozzle on the side of the nozzle 2. Both the main oxygen channel 6 and the secondary oxygen channel 7 are Laval type, which can form a supersonic oxygen jet.

[0037] Both the main and auxiliary oxygen flow channels are provided with a sleeve layer 8 on the outside. Several hollow guide ribs are evenly arranged in the cooling water inlet layer 4. The guide ribs are connected to the sleeve layer 8 to input heat-insulating gas into the sleeve layer 8. The cooling water inlet layer 4 and the cooling water outlet layer 5 are both connected to the inside of the nozzle 2 to input and output cooling water into and out of the nozzle 2.

[0038] The gun body 1 is cylindrical, with the central oxygen pipe 3, cooling water inlet layer 4, and cooling water outlet layer 5 all arranged concentrically. The tail end of the central oxygen pipe 3 is connected to an oxygen supply device to supply oxygen to the central oxygen pipe 3 and the connected main and auxiliary oxygen channels; the tail end of the cooling water inlet layer 4 is connected to a water supply device for inputting cooling water; the tail end of the cooling water outlet layer 5 is also connected to a water supply device for outputting cooling water; the water supply device is a water chiller with a circulation function.

[0039] The front end of the gun body 1 is open, and the rear end of the nozzle 2 is also open. The gun body 1 and the nozzle 2 are welded together.

[0040] The cross-section of the gun body 1 includes, from the inside to the outside, the wall of the central oxygen pipe 3, the outer wall of the cooling water inlet layer 4, and the outer wall of the cooling water outlet layer 5. The cross-section of the rear part of the nozzle 2 is also provided with concentric inner and outer three layers of pipe walls, namely the first pipe wall 9, the second pipe wall 10, and the third pipe wall 11, which are respectively welded to the wall of the central oxygen pipe 3, the outer wall of the cooling water inlet layer 4, and the outer wall of the cooling water outlet layer 5, so that the gun body 1 and the nozzle 2 form a whole, avoiding water and air leakage.

[0041] That is, the internal space of the first pipe wall 9 is connected to the central oxygen pipe 3, the internal space of the second pipe wall 10 is connected to the cooling water inlet layer 4, and the internal space of the third pipe wall 11 is connected to the cooling water outlet layer 5.

[0042] The nozzle 2 is cylindrical in shape, and the front end face of the nozzle 2 is a conical surface with the center protruding forward. The front end of the first pipe wall 9 is closed and is a conical surface with the center protruding forward. The tail ends of all the main oxygen channels 6 are connected to the conical surface of the first pipe wall 9 (i.e., the front end face of the first pipe wall 9) and communicate with the internal space of the first pipe wall 9, so that the main oxygen channels 6 are connected with the central oxygen pipe 3. The main oxygen channels 6 are inclined, and their heads are inclined towards the outside of the nozzle 2.

[0043] The front end of the second pipe wall 10 is provided with three water distribution plates 12, which are evenly distributed along the circumference of the second pipe wall 10 to guide the cooling water input into the cooling water inlet layer 4 to be distributed radially along the nozzle 2; the front end of the third pipe wall 11 is closed by the front end face of the nozzle 2, which introduces the water in the nozzle 2 into the cooling water outlet layer 5 and then discharges it.

[0044] The three main oxygen nozzles are evenly distributed around the nozzle 2. The main oxygen channel 6 is a standard Laval nozzle with a concave section cone angle of 30°, a throat diameter of 30 mm, an expansion section cone angle of 12°, and an exit Mach number of 2.0. The angle between the central axis of the main oxygen channel 6 and the central axis of the nozzle body 1 is 12°.

[0045] The auxiliary oxygen flow channel 7 passes through the three layers of pipe wall on the side of the nozzle 2, and the six auxiliary oxygen flow channels 7 are evenly distributed along the circumference of the third pipe wall 11; the centers of the main and auxiliary oxygen nozzles are not on the same radial straight line of the nozzle 2, so that the main and auxiliary oxygen nozzles are staggered in the circumference to avoid jet interference.

[0046] The secondary oxygen channel 7 is a standard Laval nozzle with a converging section cone angle of 10°, a throat diameter of 6mm, an expanding section cone angle of 6°, and an exit Mach number of 1.2. The central axis of the secondary oxygen channel 7 is perpendicular to the central axis of the nozzle body 1, that is, the tail of the secondary oxygen channel 7 is tangential to the inner side of the first pipe wall 9, so that the secondary oxygen jet can obtain a tangential velocity component.

[0047] The point furthest from the secondary oxygen flow channel 7 among the two intersections of the central axis of the secondary oxygen flow channel 7 and the outer wall of the gun body 1 is selected as reference point 13. The central axis of the gun body 1 in the width direction passing through reference point 13 is selected as reference axis 14. The angle between reference axis 14 and the central axis of the secondary oxygen flow channel 7 is 25°, so that the secondary oxygen jet forms a stable downward swirling flow, expands the spreading area, enhances mixing with CO, and avoids key areas of the furnace lining, significantly reduces the erosion rate, and extends the furnace life.

[0048] The sum of the flow rates of all auxiliary oxygen channels 7 accounts for 8-25% of the total oxygen supply of the central oxygen tube 3.

[0049] The structure of the water distribution plate 12 is the same as that of the existing secondary combustion oxygen lance, that is, the tail of the water distribution plate is connected to the head of the second pipe wall 10, and the head of the water distribution plate extends towards the center of the nozzle 2, guiding the cooling water input from the cooling water inlet layer 4 to the interior of the center of the nozzle 2. Then the cooling water flows outward from the center of the nozzle 2, distributing as evenly as possible inside the nozzle 2 to fully exert the cooling effect, and finally being discharged through the cooling water outlet pipe. The water distribution plate and the main oxygen flow channel 6 are staggered.

[0050] Six inlet guide ribs 15 and three outlet guide ribs 16 are provided on the outer side of the central oxygen pipe 3, which are respectively for inputting and outputting heat-insulating gas for each layer. The inlet guide ribs 15 and the outlet guide ribs 16 are alternately arranged and evenly distributed along the circumference of the central oxygen pipe 3.

[0051] The inlet guide rib 15 is wavy, and the outlet guide rib 16 is straight. The centerline of the inlet guide rib 15 and the outlet guide rib 16 are parallel to the central axis of the central oxygen tube 3. The inlet guide rib 15 and the outlet guide rib 16 do not contact each other.

[0052] The inlet guide rib 15 corresponds one-to-one with the sleeve of the secondary oxygen flow channel 7, and the outlet guide rib 16 corresponds one-to-one with the sleeve of the main oxygen flow channel 6.

[0053] The tops of the air intake guide rib 15 and the air outlet guide rib 16 do not contact the inner side of the outer wall of the cooling water inlet layer 4, so as to avoid the guide ribs dividing the cooling water inlet layer 4 into several areas, so that the cooling water inlet layer 4 forms an integral connected area on the outside of each guide rib.

[0054] The cross-section of the air guide rib is circular. The tails of each air intake guide rib 15 are connected in parallel and pass through the gun body 1, and then connect to the air supply device. The head of the air intake guide rib 15 extends along the outer side of the first pipe wall 9 into the nozzle 2, and then connects to the sleeve of each secondary oxygen channel 7. Then the sleeve of the secondary oxygen channel 7 is connected to the sleeve of the adjacent main oxygen channel 6 through the connecting guide rib 17.

[0055] The main oxygen flow channel 6 is connected to the head of the air outlet guide rib 16. The air outlet guide rib 16 extends the nozzle 2 along the front end face and outer side face of the first pipe wall 9. The tail ends of each air outlet guide rib 16 are connected in parallel and pass through the gun body 1, and then connect to the exhaust pipe.

[0056] The insulating gas is an inert gas at room temperature (such as nitrogen or argon). The exhaust pipe can be connected to a tail gas treatment device or discharged directly to the outside.

[0057] The sleeve 8 is a cylinder that is fitted over the outside of the main oxygen channel 6 or the auxiliary oxygen channel 7, with a gap between it and the main oxygen channel 6 or the auxiliary oxygen channel 7 to allow the insulation gas to pass through.

[0058] The central axis of the sleeve of the secondary oxygen flow channel 7 is perpendicular to the central axis of the gun body 1. The two ends of the sleeve of the secondary oxygen flow channel 7 are welded to the outer side of the first pipe wall 9 and the inner side of the third pipe wall 11, respectively. The sleeve of the secondary oxygen flow channel 7 is welded through the second pipe wall 10.

[0059] The central axis of the sleeve of the main oxygen channel 6 is parallel to the central axis of the corresponding main oxygen channel 6, and the two ends of the sleeve of the main oxygen channel 6 are respectively welded to the front end face of the first pipe wall 9 and the front end face of the nozzle 2.

[0060] The head of the air intake guide rib 15 is connected to the end of the sleeve of the secondary oxygen channel 7 near the first pipe wall 9, and the heat-insulating gas is input into the corresponding sleeve; the tail of the guide rib 17 is connected to the part of the sleeve of the corresponding secondary oxygen channel 7 near the third pipe wall 11, and the heat-insulating gas in the sleeve is discharged.

[0061] Several connecting guide ribs 17, adjacent to each other and corresponding to the same main oxygen flow channel 6, are connected in parallel and then connected to one end of the main oxygen flow channel 6 sleeve near the front end face of the first pipe wall 9, so that the heat-insulating gas discharged from several secondary oxygen flow channels 7 is introduced into the sleeve of the adjacent corresponding main oxygen flow channel 6. Every two secondary oxygen flow channels correspond to one main oxygen flow channel.

[0062] In one specific implementation, the connecting guide rib 17 extends along the outer side of the corresponding secondary oxygen flow channel 7 sleeve to the outer side of the first pipe wall 9 (during this process, the connecting guide rib 17 penetrates the second pipe wall 10), and then extends along the outer side and front end face of the first pipe wall 9 to the sleeve of the corresponding main oxygen flow channel 6; the parallel positions of several connecting guide ribs 17 can be selected on the outer side of the first pipe wall 9 or the front end face of the first pipe wall 9.

[0063] The head of the air outlet guide rib 16 is connected to one end of the main oxygen channel 6 sleeve layer near the front end face of the nozzle 2, and then the air outlet guide rib 16 extends along the outer side of the main oxygen channel 6 sleeve layer to the front end face of the first pipe wall 9.

[0064] The oxygen supplied by the gun body 1 is input from the central oxygen pipe 3, and the cooling water in the nozzle 2 is input from the cooling water inlet layer 4. The central oxygen pipe 3 is adjacent to the cooling water inlet layer 4, which will cool the supplied oxygen. If the outer walls of the main and auxiliary oxygen channels are in direct contact with the cooling water, the cooled oxygen will be ejected from the main and auxiliary oxygen nozzles and will quickly lower the temperature of the surrounding atmosphere in the furnace. This will result in a lower temperature at the secondary oxygen supply position in the furnace, which is not conducive to the overall temperature balance in the furnace, nor to the combustion of CO at the secondary oxygen supply position.

[0065] In this invention, inlet guide ribs 15 and outlet guide ribs 16 are provided on the outer surface of the central oxygen pipe 3. These guide ribs cover part of the outer surface area of ​​the central oxygen pipe 3, and heat-insulating gas flows within the guide ribs, which can, to a certain extent, block the cooling water from cooling the supplied oxygen, keeping the temperature drop of the supplied oxygen within a reasonable range. Both the main and auxiliary oxygen channels are equipped with a sleeve, and the guide ribs serve as the input and output channels for the heat-insulating gas, ensuring continued heat preservation of the oxygen in the main and auxiliary oxygen channels until the oxygen exits the nozzle 2. This invention utilizes the guide ribs and sleeve to provide a certain degree of heat preservation for the supplied oxygen, minimizing the temperature difference between the supplied oxygen and the gas inside the furnace, which is beneficial for the rapid and successful ignition of the gas inside the furnace and improves combustion efficiency. Simultaneously, because of the protection of the sleeve and heat-insulating gas, the temperature impact faced by the main and auxiliary oxygen channels is not too severe, which helps protect the pipe walls of the main and auxiliary oxygen channels and extends the service life of the nozzle 2.

[0066] On the other hand, inside the nozzle, the guide ribs and connecting guide ribs 17 are attached to the outer surface and front end face of the first pipe wall 9, without excessive contact with the outer wall of the nozzle, thus not affecting the cooling water cooling the inside of the nozzle and the cooling effect of the nozzle. At the same time, most of the guide ribs inside the nozzle are located in the cooling water inlet area, which can also increase the turbulence of the cooling water, enhance heat transfer, and improve the heat transfer efficiency of the cooling water inside the nozzle.

[0067] Since the guide ribs and sheath occupy part of the space inside the cooling water inlet layer 4 and the nozzle 2, thus compressing some of the space that should belong to the cooling water, theoretically it will affect the cooling effect. To address this issue, the present invention designs the air inlet guide rib 15 as a wave shape, which can increase the turbulence of the cooling water inlet. After the cooling water enters the nozzle 2, it enhances heat exchange and improves heat exchange efficiency to compensate for the reduction in cooling capacity caused by the reduction in cooling water space. Since the number of main oxygen channels 6 is less than the number of secondary oxygen channels 7, the number of outlet guide ribs 16 is also less than the number of inlet guide ribs 15. The outlet guide ribs 16 are set as straight lines to ensure smooth airflow and facilitate the rapid discharge of heat-insulating gas. The size of the outlet guide ribs 16 can also be appropriately increased to ensure timely exhaust.

[0068] The rib height of the intake guide rib 15 is 3mm, and the vertical distance between the center line of the intake guide rib 15 and its own peak and trough is equal and 5mm.

[0069] Unless otherwise specified, the central axis of the gun body 1 is the central axis in the length direction of the gun body 1. Only when the angle of the auxiliary oxygen channel 7 is limited, the central axis in the width direction of the gun body 1 (i.e., the central axis passing through the center of the circular cross-section of the gun body 1) is used.

[0070] In this application, 15 tons of scrap steel can be added to each furnace.

[0071] Comparative Example 1

[0072] This comparative example provides a swirling supersonic secondary combustion oxygen lance, identical to Example 1, except that both the main and auxiliary oxygen channels are cylindrical. In this example, the flow velocity of the gas ejected from the main and auxiliary oxygen nozzles is not high, failing to approach supersonic speeds. This results in a lower mixing efficiency between the ejected oxygen and the surrounding CO in the furnace compared to Example 1, leading to a lower secondary combustion efficiency.

[0073] Comparative Example 2

[0074] This comparative example provides a swirling supersonic secondary combustion oxygen lance, which is the same as Example 1, except that no jacket is provided on the outside of the main and auxiliary oxygen channels, and no guide ribs are provided in the cooling water inlet layer.

[0075] Comparative Example 3

[0076] This comparative example provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Example 1, except that the outer sides of the main and auxiliary oxygen channels are not provided with a sleeve, and there are no outlet guide ribs or connecting guide ribs; an inlet guide rib is provided, but the inlet guide rib is solid (i.e. no longer inputs heat-insulating gas) and wavy, and the inlet guide rib is staggered from the main and auxiliary oxygen channels; the inlet guide rib is evenly provided on the outer side and front end face of the first pipe wall, and on the front end face of the first pipe wall, the inlet guide rib extends radially along the front end face to the center of the front end face.

[0077] Example 2

[0078] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the air intake guide ribs are straight.

[0079] Example 3

[0080] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in embodiment 1, except that the angle between the central axis of the main oxygen flow channel and the central axis of the lance body is 16°.

[0081] Example 4

[0082] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in embodiment 1, except that the angle between the central axis of the main oxygen flow channel and the central axis of the lance body is 17°.

[0083] Example 5

[0084] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the cone angle of the contraction section of the main oxygen flow channel is 40°, the throat diameter is 60 mm, the cone angle of the expansion section is 16°, and the outlet Mach number is 2.4.

[0085] Example 6

[0086] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the cone angle of the contraction section of the main oxygen flow channel is 29°, the throat diameter is 29 mm, the cone angle of the expansion section is 11°, and the outlet Mach number is 1.9.

[0087] Example 7

[0088] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the cone angle of the contraction section of the secondary oxygen flow channel is 35°, the throat diameter is 20mm, and the cone angle of the expansion section is 12°.

[0089] Example 8

[0090] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the cone angle of the contraction section of the secondary oxygen flow channel is 9°, the throat diameter is 5mm, and the cone angle of the expansion section is 5°.

[0091] Example 9

[0092] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the angle between the reference axis and the central axis of the secondary oxygen flow channel is 45°.

[0093] Example 10

[0094] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the angle between the reference axis and the central axis of the secondary oxygen channel is 24°.

[0095] Example 11

[0096] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in embodiment 1, except that the angle between the reference axis and the central axis of the secondary oxygen flow channel is 46°.

[0097] Example 12

[0098] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the height of the inlet and outlet air guide ribs is 5mm.

[0099] Example 13

[0100] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the height of the inlet and outlet air guide ribs is 2mm.

[0101] Example 14

[0102] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in embodiment 1, except that the vertical distance between the center line of the air intake guide rib and its own peak and trough is equal and is 8mm.

[0103] Example 15

[0104] This embodiment provides a swirling supersonic secondary combustion oxygen lance, which is the same as that in Embodiment 1, except that the vertical distance between the center line of the inlet guide rib and its own peak and trough is equal and is 4mm.

[0105] The above examples and comparative examples were applied in the No. 4 furnace of Meishan Steel Plant, with a combustion temperature of 2300~2600℃ and a single use time of 16 minutes.

[0106] Table 1 Comparison of secondary combustion rate (PCR) of Examples 1, 3-11 and Comparative Example 1

[0107]

[0108] As shown in Table 1, the standard Laval-type main and auxiliary oxygen channels designed in this invention can achieve good secondary combustion efficiency. The size and angle of the main and auxiliary oxygen channels also affect the secondary combustion efficiency.

[0109] Table 2 Comparison of service life of Examples 1-2, 12-15 and Comparative Examples 2-3

[0110]

[0111] As shown in Table 2, the sleeve and air inlet guide ribs designed in this invention help to increase the turbulence of cooling water, thereby improving heat exchange efficiency, effectively protecting the nozzle and main and auxiliary oxygen channels, extending service life, and reducing replacement and maintenance costs.

Claims

1. A swirling supersonic secondary combustion oxygen lance, characterized in that, The device includes a gun body and a nozzle. The gun body, from the inside out, consists of a central oxygen pipe, a cooling water inlet layer, and a cooling water outlet layer. The nozzle is connected to the front end of the gun body. The nozzle has several main oxygen channels and several secondary oxygen channels evenly arranged inside. The tail ends of both the main and secondary oxygen channels are connected to the central oxygen pipe for oxygen supply. The head of the main oxygen channel forms a main oxygen nozzle on the front face of the nozzle, and several main oxygen nozzles are arranged in a ring. The head of the secondary oxygen channel forms a secondary oxygen nozzle on the side of the nozzle. Both the main and secondary oxygen channels are Laval type, capable of forming a supersonic oxygen jet. Both the main oxygen flow channel and the auxiliary oxygen flow channel are equipped with a sleeve on the outside. Several hollow guide ribs are evenly arranged in the cooling water inlet layer. The guide ribs are connected to the sleeve to input and output heat-insulating gas for the sleeve. The cooling water inlet layer and the cooling water outlet layer are both connected to the inside of the nozzle to input and output cooling water for the nozzle.

2. The swirling supersonic secondary combustion oxygen lance according to claim 1, characterized in that, The gun body is cylindrical, with the central oxygen pipe, cooling water inlet layer, and cooling water outlet layer all arranged concentrically. The tail end of the central oxygen pipe is connected to an oxygen supply device to supply oxygen to the central oxygen pipe and the connected main and auxiliary oxygen channels. The tail end of the cooling water inlet layer is connected to a water supply device for inputting cooling water. The tail end of the cooling water outlet layer is also connected to a water supply device for outputting cooling water. The water supply device is a water chiller with a circulation function. The front of the gun body is open, and the rear of the nozzle is also open. The gun body and the nozzle are welded together.

3. The swirling supersonic secondary combustion oxygen lance according to claim 2, characterized in that, The cross-section of the gun body includes, from the inside to the outside, a central oxygen pipe wall, an outer wall of the cooling water inlet layer, and an outer wall of the cooling water outlet layer. The cross-section of the rear part of the nozzle also has concentric inner and outer three layers of pipe walls, namely the first pipe wall, the second pipe wall, and the third pipe wall, which are welded to the central oxygen pipe wall, the outer wall of the cooling water inlet layer, and the outer wall of the cooling water outlet layer, respectively, so that the gun body and the nozzle form a whole.

4. The swirling supersonic secondary combustion oxygen lance according to claim 3, characterized in that, The nozzle is cylindrical in shape, with a conical front end that protrudes forward at the center. The front end of the first pipe wall is closed and is a conical surface that protrudes forward at the center. The tail ends of all main oxygen channels are connected to this conical surface of the first pipe wall and communicate with the internal space of the first pipe wall, so that the main oxygen channels are connected to the central oxygen pipe. The front end of the second pipe wall is provided with several water distribution plates, which are evenly distributed along the circumference of the second pipe wall to guide the cooling water input into the cooling water inlet layer to be distributed radially along the nozzle; the front end of the third pipe wall is closed by the front end face of the nozzle, which introduces the water in the nozzle into the cooling water outlet layer and then discharges it.

5. The swirling supersonic secondary combustion oxygen lance according to claim 4, characterized in that, The main oxygen nozzles are evenly distributed along the circumference of the nozzle. The main oxygen channel is a standard Laval nozzle with a conical angle of 30-40° in the contraction section, a throat diameter of 30-60 mm, a conical angle of 12-16° in the expansion section, and an exit Mach number of 2.0-2.

4. The angle between the central axis of the main oxygen channel and the central axis of the nozzle body is 12-16°.

6. The swirling supersonic secondary combustion oxygen lance according to claim 4, characterized in that, The auxiliary oxygen flow channel passes through the three layers of pipe wall on the side of the nozzle, and several auxiliary oxygen flow channels are evenly distributed along the circumference of the third pipe wall. The centers of the main and auxiliary oxygen nozzles are not located on the same radial line of the nozzle, so that the main and auxiliary oxygen nozzles are staggered circumferentially to avoid jet interference; The secondary oxygen channel is a standard Laval nozzle, with a converging section cone angle of 10-35°, a throat diameter of 6-20mm, and an expanding section cone angle of 6-12°; the central axis of the secondary oxygen channel is perpendicular to the central axis of the nozzle body.

7. The swirling supersonic secondary combustion oxygen lance according to claim 6, characterized in that, The point furthest from the secondary oxygen flow channel among the two intersections of the central axis of the secondary oxygen flow channel and the outer wall of the gun body is selected as the reference point. The central axis of the gun body in the width direction passing through the reference point is selected as the reference axis. The angle between the reference axis and the central axis of the secondary oxygen flow channel is 25-45°, so that the secondary oxygen jet forms a stable downward swirling flow, expands the spreading area, enhances mixing with CO, and avoids key areas of the furnace lining.

8. The swirling supersonic secondary combustion oxygen lance according to claim 3, characterized in that, Several inlet guide ribs and several outlet guide ribs are provided on the outer surface of the central oxygen pipe, which are respectively for inputting and outputting heat-insulating gas for each layer. The inlet guide ribs and outlet guide ribs are alternately arranged and evenly distributed along the circumference of the central oxygen pipe. The inlet guide rib is wavy, and the outlet guide rib is straight. The centerline of the inlet guide rib, the outlet guide rib and the center axis of the central oxygen pipe are parallel to each other. The inlet guide rib corresponds one-to-one with the sleeve of the auxiliary oxygen flow channel, and the outlet guide rib corresponds one-to-one with the sleeve of the main oxygen flow channel.

9. The swirling supersonic secondary combustion oxygen lance according to claim 8, characterized in that, The tails of each air intake guide rib are connected in parallel and pass through the gun body, and then connected to the air supply device; the head of the air intake guide rib extends along the outer side of the first pipe wall into the nozzle, and then connects to the sleeve of each auxiliary oxygen channel, and then the sleeve of the auxiliary oxygen channel is connected to the sleeve of the adjacent main oxygen channel through the connecting guide rib. The main oxygen flow channel is connected to the head of the outlet guide rib. The outlet guide rib extends along the front end and outer side of the first pipe wall to form a nozzle. The tails of each outlet guide rib are connected in parallel and pass through the gun body, and then connect to the exhaust pipe.

10. The swirling supersonic secondary combustion oxygen lance according to claim 1, characterized in that, The sleeve is cylindrical and is fitted outside the main oxygen flow channel or the auxiliary oxygen flow channel, with a gap between it and the main oxygen flow channel or the auxiliary oxygen flow channel to allow the insulation gas to pass through. The central axis of the sleeve of the auxiliary oxygen flow channel is perpendicular to the central axis of the gun body. The two ends of the sleeve of the auxiliary oxygen flow channel are welded to the outer side of the first pipe wall and the inner side of the third pipe wall, respectively. The sleeve of the auxiliary oxygen flow channel is welded at the position where it penetrates the second pipe wall. The central axis of the sleeve of the main oxygen flow channel is parallel to the central axis of the corresponding main oxygen flow channel. The two ends of the sleeve of the main oxygen flow channel are welded to the front end face of the first pipe wall and the front end face of the nozzle, respectively.

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