Flash lead smelting nozzle and method for determining diameter of air inlet pipe of flash lead smelting nozzle

Abstract

The invention discloses a flash lead smelting nozzle and a method for determining the diameter of an air inlet pipe of the flash lead smelting nozzle, and relates to the technical field of metal smelting. The spray pipe comprises a gas spray pipe and a material spray pipe, the bottom of the material spray pipe is connected to the top of the reaction furnace through a flange, and the material spray pipe is communicated into the reaction furnace; the gas spray pipe is coaxially sleeved in the material spray pipe and is connected through a flange; the material spraying pipe is provided with a feeding port, the gas spraying pipe is provided with a spiral gas supply assembly, the spiral gas supply assembly comprises a plurality of gas inlet pipes, and the gas inlet pipes are communicated with the gas spraying pipe; the plurality of gas inlet pipes are tangentially arranged relative to the gas spraying pipe and are in center symmetry relative to the gas spraying pipe; according to the method, the influence of tangential wind speed on axial wind speed is considered, so that a certain requirement is made for the diameter of the air inlet pipe, and the rotational flow stability is ensured; through the arrangement of the gas spraying pipe, the material spraying pipe and the gas inlet pipe, the nozzle is divided into the inner area and the outer area, and rotational flow is generated in the gas spraying pipe through the gas inlet pipe, so that the retention time of materials in the air of the reaction furnace is prolonged, the materials can be fully reacted, and the lead smelting efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a flash lead smelting nozzle and a method for determining the diameter of an air inlet pipe thereof. Background Art

[0002] Flash smelting of lead-based polymetallic materials (mainly including lead sulfide concentrate and polymetallic solid waste slag) is usually completed through a reactor. A nozzle is installed on the top of the reactor. During the reaction process, oxygen-enriched air and ground concentrate are sprayed from the flash lead smelting nozzle to complete gas-particle mixed combustion in the air of the furnace. The current flash lead smelting nozzle structure is as follows: Figure 1 As shown in the figure, it is mainly composed of central oxygen and side oxygen outlets. The oxygen-enriched air consists of two parts, one part is ejected from the middle central outlet, and most of it is ejected at high speed from the narrow side oxygen outlets around. The material is ejected from the middle channel between the central oxygen and the side oxygen. According to the Bernoulli equation, the high-speed ejected airflow can ensure that the charge channel maintains negative pressure. Therefore, the force to maintain the charge descending is divided into two parts, one is its own gravity, and the other is the pressure sucked from the inside of the reaction tower by the high-speed airflow.

[0003] Production practice has shown that although this method of feeding is simple, the problem is that the charge is not broken up enough in the air. In order to form a negative pressure in the charge channel, high-speed gas is sprayed vertically downward and stays in the air for a short time. Therefore, under the traditional nozzle structure, the concentrate particles are not burned completely, the residence time in the air is insufficient, and the nozzles are often burned. A series of factors make it impossible to increase the charge amount in the furnace, limiting the efficiency of flash lead smelting. Summary of the invention

[0004] In order to increase the residence time of concentrate particles in the air and thus improve the efficiency of flash lead smelting, the present application provides a flash lead smelting nozzle and a method for determining the diameter of its air inlet pipe.

[0005] The present application provides a flash lead smelting nozzle and a method for determining the diameter of its intake pipe, which adopts the following technical solution:

[0006] A flash lead smelting nozzle comprises a gas nozzle and a material nozzle, wherein the bottom of the material nozzle is connected to the top of a reaction furnace via a flange; the gas nozzle is coaxially sleeved in the material nozzle and connected via a flange; a feed port is provided on the material nozzle, and a spiral gas supply assembly is provided on the gas nozzle, wherein the spiral gas supply assembly comprises a plurality of air inlet pipes, and the air inlet pipes are connected to the gas nozzle; the plurality of air inlet pipes are tangentially arranged with respect to the gas nozzle and are symmetrical with respect to the center of a circle of the gas nozzle.

[0007] Optionally, the material nozzle includes an upper material stacking area, a connecting area and a lower material discharge area which are connected in sequence, the upper material stacking area is in the shape of a trumpet with a larger top and a smaller bottom, the upper section of the connecting area is in the shape of a straight cylinder, the lower section is in the shape of a trumpet with a larger top and a smaller bottom, and the lower material discharge area is in the shape of a straight cylinder.

[0008] Optionally, a plurality of air inlets for blowing in flowing air are further provided on the side walls of the upper material stacking area.

[0009] Optionally, the difference between the inner diameter of the lower material discharge zone and the outer diameter of the gas nozzle is greater than 4 times the maximum diameter of the coke particles.

[0010] Optionally, a transparent sight glass is provided on the top of the gas nozzle.

[0011] Optionally, the gas nozzle is provided with a plurality of swirl components at intervals along the length direction, the swirl component comprises an inner ring, the outer wall of the inner ring is provided with a plurality of spiral blades along the forward direction, and the plurality of spiral blades are all connected to the inner wall of the gas nozzle.

[0012] Optionally, the swirl components are evenly spaced and arranged in three groups, with a spacing of 600 mm between two swirl components.

[0013] Optionally, the lower section of the gas nozzle extends out of the material nozzle.

[0014] In a second aspect, the present application also provides a flash lead smelting nozzle and a method for determining the diameter of its intake pipe, which adopts the following technical solution:

[0015] A flash lead smelting nozzle and a method for determining the diameter of its intake pipe, comprising the following contents:

[0016] When the airflow enters tangentially from two directions at the same speed, the airflow velocity field in the duct is usually determined by the tangential component and the axial component; if the tangential wind speed is too high, the axial speed of the airflow will appear relatively small relative to the radius r of the gas nozzle duct, resulting in unstable swirl or even loss of rotation. By solving the above equation, the direction of airflow movement inside the duct can be obtained. After calculation, when the tangential air velocity V 切向 Greater than the axial speed V 轴向 When the air volume is Q, the inner diameter of the gas nozzle is D, the cross-sectional area of ​​the air inlet is S, and the number of air inlets is N, the following conditions must be met:

[0017]

[0018] V 切向 <2·V 轴向 .

[0019] In summary, this application includes the following beneficial technical effects:

[0020] The present application divides the nozzle into an inner zone and an outer zone by arranging a gas nozzle, a material nozzle and an air inlet pipe, and generates a swirl in the gas nozzle through the air inlet pipe, thereby increasing the residence time of the material in the air of the reactor so that it can be fully reacted, thereby improving the lead smelting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of a conventional nozzle in the prior art.

[0022] Figure 2 This is the overall structural diagram of the flash lead smelting nozzle of the present application;

[0023] Figure 3 yes Figure 2 A cross-sectional view of the structure;

[0024] Figure 4 yes Figure 2 The overall structure diagram of the middle structure from another perspective;

[0025] Figure 5 yes Figure 3 A structural cross-sectional view of the middle swirl assembly;

[0026] Figure 6 , 7 This is a simulation diagram used to determine the effect of the number and spacing of swirl components.

[0027] Description of reference numerals:

[0028] 1. Gas nozzle; 11. Air inlet pipe; 12. Swirl assembly; 121. Inner ring; 122. Spiral blade; 13. Transparent sight glass; 2. Material nozzle; 21. Upper material stacking area; 211. Material feed port; 212. Air inlet; 22. Connection area; 23. Lower material unloading area. DETAILED DESCRIPTION

[0029] The following is combined with Figure 1-6 This application is described in further detail.

[0030] refer to Figure 2 , 3 4. The embodiment of the present application discloses a flash lead smelting nozzle, which is installed on the top of a reactor and is used to feed materials into the reactor; the nozzle includes a gas nozzle 1 and a material nozzle 2, the bottom of the material nozzle 2 is detachably connected to the top of the reactor through a flange, the gas nozzle 1 is coaxially sleeved in the material nozzle 2, and the two are detachably connected through a flange; the top of the gas nozzle 1 extends out of the material nozzle 2, and is connected with two air inlet pipes 11, the air inlet pipes 11 are tangentially arranged with respect to the gas nozzle 1, and the two air inlet pipes 11 are symmetrical with respect to the center of the gas nozzle 1; the gas enters the gas nozzle 1 from the air inlet pipe 11, thereby forming a vortex in the gas nozzle 1.

[0031] The material nozzle 2 includes an upper material piling area 21, a connecting area 22 and a lower material discharging area 23 which are connected in sequence. The upper material piling area 21 is in the shape of a trumpet with a larger upper portion and a smaller lower portion. A feeding port 211 for material entry is provided at the top of the upper material piling area 21. The upper section of the connecting area 22 is in the shape of a straight cylinder, and the lower section is in the shape of a trumpet with a larger upper portion and a smaller lower portion. The lower material discharging area 23 is in the shape of a straight cylinder. The material enters the upper material piling area 21 from the feeding port 211, and enters the reactor through the connecting area 22 and the lower material discharging area 23 under the action of gravity.

[0032] In order to allow the material to enter the reactor smoothly, two air inlets 212 for blowing flowing air are provided on the side wall of the upper material stacking area 21 to prevent the material from being blocked inside the nozzle, and to form a positive gas pressure in the material falling area to prevent gas backflow; at the same time, in order to allow the material to pass through the lower material discharge area 23 smoothly, it is necessary to control the size of the annular area between the gas nozzle 1 and the lower material discharge area 23. In the embodiment of the present application, the difference between the inner diameter of the lower material discharge area 23 and the outer diameter of the gas nozzle 1 is greater than 4 times the maximum diameter of the coke particles; this can prevent the coke particles from "bridging" and causing blockage.

[0033] Since the present application divides the nozzle into two channels, a transparent sight glass 13 can be fixed on the top of the gas nozzle 1 through a double flange, and the slagging and burning conditions in the nozzle area can be observed through the sight glass. When slagging occurs, the transparent sight glass 13 can be pulled out and a poking rod can be inserted to clean the furnace without stopping.

[0034] At the same time, when the gas nozzle 1 is burned, the flange between the gas nozzle 1 and the material nozzle 2 can be disassembled to pull out the gas nozzle 1 for replacement, which greatly increases the maintenance efficiency of the nozzle, prolongs the life of the nozzle, and increases the labor operation rate.

[0035] Under a certain flow rate, too high a tangential velocity may cause the airflow to be unable to maintain a stable rotation, especially at high speeds, the stability of the swirl center will be destroyed; Figure 6 It can be seen that because the pipeline path through which the swirl airflow passes is too long, the axial airflow gradually increases, and the tangential airflow completely disappears due to the long-term consumption of angular momentum. At this time, the cyclone fails and the airflow flows vertically downward;

[0036] Therefore, the gas nozzle 1 is provided with a plurality of swirl components 12 at intervals along the length direction, and the swirl components 12 include an inner ring 121, and the outer wall of the inner ring 121 is provided with a plurality of spiral blades 122 along the forward direction, and the plurality of spiral blades 122 are connected to the inner wall of the gas nozzle 1; specifically, the gas nozzle 1 in the present application is 1.2 to 2.4 meters long, and is determined according to the on-site civil engineering conditions. When the pipe length exceeds 1.8 meters, one group of swirl components is added every 600 mm; three groups of swirl components 12 are evenly spaced, and the interval between two swirl components 12 is 600 mm; from Figure 7It can be seen that the airflow after passing through the multiple swirl blades is ejected in a spiral shape. It can effectively change the movement path of the concentrate particles in the air; the particle air residence time calculated by actual measurement under this working condition is 1.9s, while Figure 1 The air residence time of the medium particles is 1.5s.

[0037] The calculation principle of the particle air residence time is as follows: For the interaction between particles and airflow, solving the following equation can obtain the particle velocity distribution in each calculation unit.

[0038]

[0039] m i is the mass of particle i, r i is the distance moved by particle i; is the acceleration of particle i, It is the resistance (drag) between the particles and the airflow. is the gravitational force on the particle. are other forces that the particle may be subject to.

[0040] The movement of particles in the airflow is mainly affected by the drag force, which is used to describe the interaction between particles and airflow. According to Stokes' law, when the particle is smaller than the critical particle size, the drag force can be expressed by the following formula:

[0041]

[0042] C d is the drag coefficient of the particle (related to the Reynolds number). g is the density of the gas, is the diameter of the particle.

[0043]

[0044] u g is the velocity vector of the airflow. i is the velocity vector of the particle.

[0045] Through the above formula, the furnace structure is discretized in the calculation, and the speed and pressure distribution of the airflow and particles inside the furnace can be obtained by solving the above formula iteratively by computer.

[0046] The residence time of the particle τ particle It can be calculated by integrating the path length of the particle and the velocity of the particle along the direction:

[0047]

[0048] L is the path length traveled by the particle; v p(r(l)) is the velocity of the particle at a point along the path, usually the relative velocity between the particle and the fluid.

[0049] Compared with the previous structure, the length of the particle path in the air is extended due to the influence of the swirling airflow, and the residence time of the charge in the air can be increased by 20% to 30%.

[0050] The present application also provides a method for determining the diameter of the air inlet pipe in the above-mentioned flash lead smelting nozzle, the content of which is as follows:

[0051] A method for determining the proportion of cyclone inlet: In a circular duct, when the air is tangentially introduced from two directions, if the air flow velocity is too high, the cyclone (swirl) may not form or become stable. This is mainly related to the interaction of airflow, the geometry of the duct, the air flow velocity, and the degree of turbulence. The formation of a cyclone requires certain conditions. Too high a tangential air flow velocity may lead to the following situations: 1. Excessive turbulence of the airflow: When the tangential air flow velocity is too high, the airflow becomes more turbulent and may destroy the expected swirl structure. Turbulence will cause the airflow to be unable to maintain a stable rotational motion and become turbulent, thereby losing the characteristics of a cyclone. 2. Imbalance of flow velocity: When the air is introduced from two directions, if the speed difference between the two airflows is too large, the center of rotation may no longer be stable, forming an uneven airflow distribution. The rotating airflow may be asymmetric, making it impossible to form a stable cyclone. 3. Insufficient angular momentum: The formation of a swirl depends on the angular momentum of the airflow in the duct. If the tangential air flow velocity is too high, the angular momentum of the airflow may be excessively consumed or unevenly distributed, making it impossible to maintain a continuous rotational flow.

[0052] When the airflow enters tangentially from two directions at the same speed, the airflow velocity field in the duct is usually determined by the tangential component and the axial component. Computational fluid dynamics (CFD) is used to iteratively calculate the velocity distribution of the airflow and particles in the computer. For the movement of the airflow, the continuity equation is first solved:

[0053]

[0054] Where ρ is the airflow density, t is the motion time, is the change of fluid density with time, and u is the velocity vector.

[0055] Then, based on the momentum conservation equation, the velocity distribution of the airflow in each calculation unit is solved jointly.

[0056]

[0057] is the momentum convection term, τ is the viscous stress tensor, which represents the distribution of friction in the fluid, and f is the external force, only gravity is considered here. p is the pressure, Represents the force exerted by pressure on a fluid.

[0058] When the airflow enters tangentially from two directions at the same speed, the airflow velocity field in the duct is usually determined by the tangential component and the axial component. If the tangential wind speed is too high, the axial speed of the airflow will be relatively small relative to the radius r of the duct, resulting in unstable swirl or even loss of rotation. By solving the above equation, the direction of airflow movement inside the duct can be obtained. After calculation, when the tangential air inlet speed is greater than twice the axial speed, a cyclone cannot be formed. The air volume is Q (m3 / h), the internal duct diameter is D, the air inlet area is S. The number of air inlets is N, and it must satisfy

[0059]

[0060] V 切向 <2·V 轴向 .

[0061] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A flash lead smelting nozzle, characterized in that: It includes a gas nozzle and a material nozzle. The bottom of the material nozzle is connected to the top of the reactor through a flange, and the material nozzle is connected to the reactor. The gas nozzle is coaxially sleeved in the material nozzle and connected through a flange. A feed port is provided on the material nozzle, and a spiral air supply assembly is provided on the gas nozzle. The spiral air supply assembly includes multiple air inlet pipes, and the air inlet pipes are connected to the gas nozzle. The multiple air inlet pipes are tangentially arranged with respect to the gas nozzle and are symmetrical with respect to the center of the gas nozzle.

2. A flash lead smelting nozzle according to claim 1, characterized in that: The material nozzle comprises an upper material piling area, a connecting area and a lower material discharging area which are connected in sequence. The upper material piling area is in a trumpet shape which is larger at the top and smaller at the bottom. The upper section of the connecting area is in a straight cylinder shape, the lower section is in a trumpet shape which is larger at the top and smaller at the bottom. The lower material discharging area is in a straight cylinder shape.

3. A flash lead smelting nozzle according to claim 2, characterized in that: The side wall of the upper material stacking area is also provided with a plurality of air inlets for blowing in flowing air.

4. A flash lead smelting nozzle according to claim 3, characterized in that: The difference between the inner diameter of the lower material discharge zone and the outer diameter of the gas nozzle is greater than 4 times the maximum diameter of the coke particles.

5. A flash lead smelting nozzle according to claim 3, characterized in that: A transparent sight glass is arranged on the top of the gas nozzle.

6. A flash lead smelting nozzle according to claim 5, characterized in that: The gas nozzle is provided with a plurality of swirl components at intervals along the length direction. The swirl components include an inner ring. The outer wall of the inner ring is provided with a plurality of spiral blades along the direction of travel. The plurality of spiral blades are all connected to the inner wall of the gas nozzle.

7. A flash lead smelting nozzle according to claim 6, characterized in that: The swirl components are evenly spaced and arranged in three groups, with a spacing of 600 mm between two swirl components.

8. A flash lead smelting nozzle according to claim 1, characterized in that: The lower section of the gas nozzle extends out of the material nozzle.

9. A method for determining the diameter of an intake pipe according to claim 1, characterized in that The steps include: When the airflow enters tangentially from two directions at the same speed, the airflow velocity field in the duct is usually determined by the tangential component and the axial component; if the tangential wind speed is too high, the axial speed of the airflow will appear relatively small relative to the radius r of the gas nozzle duct, resulting in unstable swirl or even loss of rotation. By solving the above equations, the direction of airflow movement inside the duct can be obtained. After calculation, when the tangential air inlet speed is greater than twice the axial speed, a cyclone cannot be formed. The air volume is Q, the inner diameter of the gas nozzle is D, and the cross-sectional area of ​​the air inlet pipe is S. The number of air inlets is N, which must meet the following requirements: V 切向 <2 V 轴向 。

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