Device for stabilizing metallization ratio of direct reduction iron and using method thereof

Abstract

The invention relates to a device for stabilizing the metallization ratio of direct reduction iron and a use method. The device is connected with a discharge port of the fluidized bed and comprises a rotary sealing valve, an air bellow, a grate net, a heat exchanger, a fan, a cyclone separator, a storage bin, a lower outlet of the air bellow, a temperature measuring device and a flow measuring device, the discharge port of the fluidized bed is connected with the air bellow, the rotary sealing valve is arranged on a pipeline, the fan is arranged at the bottom of the air bellow, and the heat exchanger is arranged between the air bellow and the fan. An upper outlet of the air bellow is connected with an inlet of the cyclone separator, a storage bin a is arranged at an outlet of the cyclone separator, a grid mesh is obliquely arranged in the air bellow, a lower outlet of the air bellow is arranged at the tail end of the grid mesh and connected with the inclined chute, and a storage bin b is arranged at an outlet of the inclined chute. According to the method, the wind power is calculated and adjusted, so that the obtained final product is the direct reduced iron with the set target metallization ratio or above.

Description

Technical Field

[0001] This invention relates to the field of hydrogen metallurgy, and more particularly to an apparatus for stabilizing the direct reduction rate of iron metallization and its method of use. Background Technology

[0002] The metallization rate of direct reduced iron (DRI) indicates the proportion of metallic iron (including Fe3C) in total iron, and also reflects the degree to which iron oxide in iron ore is reduced to metallic iron. Studies have shown that for every 1% increase in metallization rate, the electric furnace metal yield increases by 0.3%–0.5%, electrode consumption decreases by 0.05 kg / t–1.0 kg / t, refractory material consumption decreases by 0.3 kg / t, power consumption decreases by 3 kWh / t–15 kWh / t, and production efficiency increases by 0.6%–1.2%. The higher the metallization rate of DRI, the more it helps to reduce process operating costs, reduce consumption, and improve production efficiency. Therefore, DRI with a higher metallization rate should be prepared as much as possible.

[0003] However, due to the random distribution and residence time of iron ore particles during fluidized bed hydrogen metallurgy, the metallization rate of direct reduced iron from the fluidized bed varies, and the iron particles are mixed together, which is not conducive to further processing at a lower cost and higher efficiency. Summary of the Invention

[0004] In response to the aforementioned technical problems, an apparatus for stabilizing the direct reduction of iron metallization rate and its usage method are provided.

[0005] The technical means employed in this invention are as follows: A device for stabilizing the direct reduction of iron metallization rate is disclosed. The device is connected to the outlet of a fluidized bed and includes a rotary sealing valve, a bellows, a grate screen, a heat exchanger, a blower, a cyclone separator, a storage silo a, a lower outlet of the bellows, a storage silo b, a temperature measuring instrument, and a flow measuring instrument. The fluidized bed outlet is connected to the bellows via a pipeline, on which the rotary sealing valve is installed. A blower is installed at the bottom of the bellows. A heat exchanger is installed on the pipeline connecting the bellows and the blower. The upper outlet of the bellows is connected to the inlet of the cyclone separator. Storage silo a is located at the outlet of the cyclone separator. A grate screen is installed at an incline inside the bellows, with the end of the grate screen serving as the lower outlet of the bellows. The lower outlet of the bellows is connected to an inclined chute. Storage silo b is located at the outlet of the inclined chute. A temperature measuring instrument is installed on the pipeline connecting the bellows and the heat exchanger, and an airflow measuring instrument is installed on the pipeline between the heat exchanger and the blower.

[0006] Furthermore, the output end of the storage silo a is connected to the fluidized bed.

[0007] Furthermore, the material of the grate mesh is high-temperature resistant steel, and the mesh size is less than or equal to 35 mesh.

[0008] Furthermore, the grate bar screen is arranged such that the side of the air box inlet is high and the side of the outlet is low, forming an angle of 15° to 85° with the horizontal plane.

[0009] Furthermore, the blower is a variable-frequency centrifugal blower, which blows hydrogen or nitrogen into the air box and can adjust the blowing air volume and air speed.

[0010] Furthermore, the heat exchanger heats up the gas blown into the air box through a heat source, and the temperature rise is controlled within the range of 300°C to 600°C.

[0011] The present invention also discloses a method for using the device for stabilizing the metallization rate of direct reduced iron, including the following steps: Step 1: Set the target value of the required metallization rate of direct reduced iron as D, obtain the bulk density range of direct reduced iron with a metallization rate of D, and take the lower limit value ρ0; Step 2: Obtain the cross-sectional area A of the columnar cross-section of the air box; Step 3: Calculate and determine the critical suspension air speed, and then confirm the air volume required to be blown into the air box; Step 4: Monitor the air volume and the temperature in the heat exchanger pipeline. After reaching the preset values, carry out the work of fluidized bed reduced iron. The materials at the outlet enter the storage bins a and b; Step 5: Detect the metallization rate D1 and the bulk density ρ1 of the direct reduced iron in the storage bin b, and compare them with the target value D of the required metallization rate of direct reduced iron and the corresponding ρ0; If D1 > D, based on the bulk density ρ1, adjust the bulk density downward, and repeat steps 2 - 5; If D1 < D, based on the bulk density ρ1, adjust the bulk density upward, and repeat steps 2 - 5; If D1 = D, at this time, the storage bin a is the final required product - direct reduced iron with a metallization rate higher than or equal to the set target.

[0012] Compared with the prior art, the present invention has the following advantages: By utilizing the aerodynamic characteristics and the large difference in the density of direct reduced iron with different metallization rates (1.2t / m 3 ~2t / m 3 ), through the air separation method at the discharge port of the fluidized bed hydrogen metallurgy, by setting the metallization rate of the required direct reduced iron and calculating and adjusting the wind force, the final product obtained is direct reduced iron with a metallization rate above the set target. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] In the diagram: 1-fluidized bed; 2-rotary sealing valve; 3-wind box; 4-grate; 5-temperature measuring instrument; 6-heat exchanger; 7-airflow measuring instrument; 8-fan; 9-upper outlet of the wind box; 10-gas exhaust outlet; 11-cyclone separator; 12-storage bin a; 13-lower outlet of the wind box; 14-storage bin b. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0020] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0021] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0022] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0023] like Figure 1As shown in the figure, this invention discloses a device for stabilizing the direct reduction of iron metallization rate. This device is connected to the outlet of a fluidized bed 1 and includes a rotary sealing valve, a wind box, a grate screen, a heat exchanger, a blower, a cyclone separator, a storage silo a, a lower outlet of the wind box, a storage silo b, a temperature measuring instrument, and a flow measuring instrument. The fluidized bed outlet is connected to the wind box 3 via a pipeline, on which a rotary sealing valve 2 is installed. A blower 8 is installed at the bottom of the wind box, and a [missing information - likely a device name or function] is installed on the pipeline connecting the wind box and the blower. The heat exchanger 6 has its upper outlet 9 connected to the inlet of the cyclone separator 11. The upper outlet 9 of the air box is connected to a gas outlet 10. A storage silo a12 is located at the outlet of the cyclone separator. A grate mesh 4 is installed at an incline inside the air box, with the end of the grate mesh serving as the lower outlet 13. The lower outlet of the air box is connected to an inclined chute, and a storage silo b14 is located at the outlet of the inclined chute. A temperature measuring instrument 5 is installed on the pipeline connecting the air box and the heat exchanger, and an airflow measuring instrument 7 is installed on the pipeline between the heat exchanger and the fan. The temperature measuring instrument measures the temperature of the gas after heat exchange with the heat exchanger. The airflow measuring instrument measures the flow rate of the gas exiting the fan. The cyclone separator separates solid powder from the gas.

[0024] The rotary sealing valve is designed to prevent air from the air box from blowing back into the fluidized bed, which could cause problems such as uneven material discharge or even no material discharge at all.

[0025] Furthermore, the output end of the storage silo a is connected to the fluidized bed.

[0026] Furthermore, the grate mesh is made of high-temperature resistant steel, and the mesh size is less than or equal to 35 mesh. This ensures that the airflow from the bottom of the bellows can pass through the screen, but the material cannot.

[0027] Furthermore, the grate screen is configured such that the feed inlet side of the air box is higher than the discharge outlet side, forming an angle of 15° to 85° with the horizontal plane. This allows the material on the grate screen to slide down to the lower right outlet of the air box under its own weight, and then enter the storage silo b through the inclined chute.

[0028] Furthermore, the blower is a variable frequency centrifugal blower that blows hydrogen or nitrogen into the air box and can adjust the blowing volume and speed.

[0029] Furthermore, the heat exchanger heats the gas blown into the air box through a heat source, and the temperature is controlled between 300°C and 600°C.

[0030] The present invention also discloses a method for using the above-mentioned apparatus for stabilizing the direct reduction of iron metallization, comprising the following steps: Step 1: Set the target value of the metallization rate of the direct reduced iron to be D, obtain the bulk density range of the direct reduced iron with a metallization rate of D, and take the lower limit value ρ0; specifically, by referring to the bulk density range of the direct reduced iron with a metallization rate of D, take the lower limit value ρ0 (unit: kg / m 3 ); Step 2: Obtain the cross-sectional area A (unit: m 2 ) of the bellows cylindrical cross-section; Step 3: Calculate and determine the critical suspension wind speed, and then confirm the air volume required to be blown into the bellows; Specifically, calculate and determine the critical suspension wind speed (unit: m / s) according to the Stokes formula correction method:

[0031] where k is the shape correction coefficient, for spherical particles k = 1.0, the air density ρ 空 = 1.2 kg / m 3 , and the equivalent diameter d of the material is 8 mm.

[0032] Confirm the air volume required to be blown into the bellows based on the following formula: Q = A × γ × 3600 (unit: m³ / h) Step 4: Adjust the air volume of the fan to the value of Q by adjusting the fan speed. The heat exchanger heats the air blown by the fan to 300°C - 600°C through an external heat source, monitor the air volume and the temperature in the heat exchanger pipeline. After reaching the preset values, carry out the work of fluidized bed reduced iron, and the materials at the discharge port enter the storage bins a and b; among them, the solid powder particles coming out of the cyclone separator enter the storage bin a, which will be reloaded into the fluidized bed for further reduction treatment; the materials separated from the lower right outlet of the bellows enter the storage bin b through the inclined chute; Step 5: Detect the metallization rate D1 and bulk density ρ1 of the direct reduced iron in the storage bin b, and compare them with the set target value D of the metallization rate of the required direct reduced iron and the corresponding ρ0; If D1 > D, based on the bulk density ρ1, adjust the bulk density downward and repeat steps 2 - 5; If D1 < D, based on the bulk density ρ1, adjust the bulk density upward and repeat steps 2 - 5; If D1 = D, at this time, the storage bin a is the final required product - direct reduced iron with a metallization rate higher than or equal to the set target.

[0033] Example 1 Regarding the usage method of the specific device for stabilizing the metallization rate of direct reduced iron, the examples are as follows: Set the target value of the metallization rate of the required direct reduced iron to be 80% - 90%; Consulting the range of bulk density of directly reduced iron with a metallization rate of 80%, we take its lower limit of 1200 (unit: kg / m³). 3 ); The measured cross-sectional area A of the bellows cylinder is 10 (unit: m). 2 ); The critical suspension wind speed γ was determined to be 2.83 m / s based on the Stokes formula correction method. Calculate the required air volume entering the blower housing: Q = A ×γ × 3600 = 101772 m³ / h Adjust the fan speed to 1350 rpm and adjust the fan volume to approximately 101772 m³ / h; The heat exchanger uses an external heat source to transfer heat from the blower air to 300℃~600℃; Solid powder particles from the cyclone separator enter storage silo a, where they will be recycled back into the fluidized bed for further reduction processing. Material separated from the lower right outlet of the blower enters storage silo b via an inclined chute. The metallization rate of direct reduced iron in storage silo b was measured to be D1=78.9% and the bulk density was ρ1=1320kg / m³. 3 ; With a bulk density ρ11320kg / m³ 3 Based on this, increase by 200 kg / m each time. 3 Adjust the bulk density to 1520 kg / m³ 3 The critical suspension wind speed γ was determined to be 3.18 m / s based on the Stokes formula correction method. Calculate the required air volume entering the blower housing: Q = A ×γ × 3600 = 114551 m³ / h By adjusting the fan speed by 50 rpm each day until it reaches 1550 rpm, the fan volume is adjusted to approximately 11500 m³ / h. The heat exchanger uses an external heat source to transfer heat from the blower air to 300℃~600℃; Solid powder particles from the cyclone separator enter storage silo a, where they will be recycled back into the fluidized bed for further reduction processing. Material separated from the lower right outlet of the blower enters storage silo b via an inclined chute. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An apparatus for stabilizing the direct reduction of iron metallization rate, characterized in that, The device is connected to the outlet of the fluidized bed, and includes a rotary seal valve, an air box, a grate screen, a heat exchanger, a fan, a cyclone separator, a storage bin a, an outlet at the lower part of the air box, a storage bin b, a temperature measuring instrument and a flow measuring instrument. The outlet of the fluidized bed is connected to the air box through a pipeline, and a rotary seal valve is arranged on this pipeline. A fan is arranged at the bottom of the air box, and a heat exchanger is arranged on the pipeline connecting the air box and the fan. The upper outlet of the air box is connected to the inlet of the cyclone separator, and a storage bin a is arranged at the outlet of the cyclone separator. A grate screen is inclinedly arranged inside the air box, and the end of the grate screen is the outlet at the lower part of the air box. The outlet at the lower part of the air box is connected to an inclined chute, and a storage bin b is arranged at the outlet of the inclined chute. A temperature measuring instrument is arranged on the pipeline connecting the air box and the heat exchanger, and an air volume measuring instrument is arranged on the pipeline between the heat exchanger and the fan.

2. The apparatus for stabilizing the direct reduction of iron metallization rate according to claim 1, characterized in that, The output end of the storage bin a is connected to the fluidized bed.

3. The apparatus for stabilizing the direct reduction of iron metallization rate according to claim 1, characterized in that, The material of the grate screen is high-temperature resistant steel, and the mesh specification meets less than or equal to 35 meshes.

4. The apparatus for stabilizing the direct reduction of iron metallization rate according to claim 1, characterized in that, The grate screen is arranged such that the side of the air box inlet is high and the side of the outlet is low, and it forms an angle of 15° - 85° with the horizontal plane.

5. The apparatus for stabilizing the direct reduction of iron metallization rate according to claim 1, characterized in that, The fan is a variable-frequency centrifugal fan, which blows hydrogen or nitrogen into the air box and can adjust the blown air volume and air speed.

6. The apparatus for stabilizing the direct reduction of iron metallization rate according to claim 1, characterized in that, The heat exchanger heats up the gas blown into the air box through a heat source, and the temperature rise is controlled within 300°C - 6°C.

7. A method of using the apparatus for stabilizing the direct reduction of iron metallization as described in any one of claims 1 to 5, characterized in that, It includes the following steps: Step 1: Set the target value of the metallization rate of the desired direct reduced iron as D, obtain the bulk density range of the direct reduced iron with the metallization rate of D, and take its lower limit value ρ0; Step 2: Obtain the cross-sectional area A of the cylindrical cross-section of the air box; Step 3: Calculate and determine the critical suspension air speed, and then confirm the air volume required to be blown into the air box; Step 4: Monitor the air volume and the temperature in the pipeline of the heat exchanger. After reaching the preset value, carry out the work of fluidized bed reduced iron, and the materials at the outlet enter the storage bin a and the storage bin b; Step 5: Detect the metallization rate D1 and bulk density ρ1 of the direct reduced iron in the storage bin b, and compare them with the set target value D of the desired direct reduced iron metallization rate and the corresponding ρ0; If D1 > D, based on the bulk density ρ1, adjust the bulk density downward, and repeat steps 2 - 5; If D1 < D, based on the bulk density ρ1, adjust the bulk density upward, and repeat steps 2 - 5; If D1 = D, at this time, the storage bin a is the final required product - direct reduced iron with a metallization rate higher than or equal to the set target.

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