Methods for handling filler layers stored inside cylindrical containers

Abstract

This invention provides a method for processing a filling layer that can suppress the flow of filling particles. The method for processing a filling layer contained in a cylindrical container of this invention is characterized by performing the following steps under the condition of satisfying the following formula (1), that is, in the state where the filling layer is contained in the cylindrical container, a first gas is supplied into the cylindrical container from a nozzle provided on the side of the cylindrical container. DT / DP≦12×(Pinj / Ph)-0.21 . . . (1) Here, DT: vertical length of the nozzle orifice (m), DP: the blended average particle size (m) of all filling particles constituting the filling layer, Pinj: horizontal blowing pressure (Pa) of the first gas at the height position of the nozzle, Ph: horizontal powder pressure (Pa) of the filling layer at the height position of the nozzle.

Description

Technical Field

[0001] This invention relates to a method for processing a filling layer housed within a cylindrical container containing a blast furnace. Prior Technology

[0002] In recent years, there has been a growing trend towards reducing CO2 (carbon dioxide) emissions, a greenhouse gas, leading to an urgent need to reduce the amount of coal-based reducing materials used in blast furnace operations. Reducing materials function by converting coal into heat within the furnace to raise the temperature of the charge and by reducing iron-based raw materials (iron ore, sintered iron ore, granulated iron ore, etc.) within the furnace. Hydrogen has attracted considerable attention as a reducing material aimed at reducing CO2 emissions. Because hydrogen's reduction rate is faster than that of CO, blowing hydrogen-based reducing gases into the blast furnace can simultaneously reduce CO2 emissions and improve reduction efficiency.

[0003] Since the reduction of iron-based raw materials using hydrogen is an endothermic reaction, the following problems exist: the heating of the charge in the blast furnace is delayed, making successful reduction impossible. Furthermore, when high-temperature gas is blown into the shaft to prevent poor heating of the charge, fluidization of the charge particle packing layer occurs, leading to unstable descent of the charge. Therefore, an operating method has been disclosed to prevent fluidization of the packing particles constituting the packing layer and simultaneously avoid the impact of poor heating of the charge in the upper part of the furnace. Patent Document 1 discloses an operating method for a blast furnace in which hot blast with an oxygen enrichment of 20% by volume or less is blown into the blast furnace through the tuyeres, and preheated gas is blown into the blast furnace through a preheated gas inlet at a predetermined location. Patent Document 2 discloses an operating method for a blast furnace in which the flow velocity of the blast furnace body gas is set to 100 m / s or less when the blast furnace body gas is blown in.

[0004] Furthermore, as will be described later, Non-Patent Document 1 discloses a method for measuring the internal friction angle of powder, Non-Patent Document 2 discloses a method for measuring the wall friction angle of powder, and Non-Patent Document 3 discloses the composition of a blast furnace simulation model. [Previous Technical Documents] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-149085 Patent Document 2: Japanese Patent Application Publication No. 2011-231350 [Non-patent literature]

[0006] Non-patent literature 1: Ryuichi Aoki, "Method for Determining the Angle of Repose and Angle of Internal Friction of Powders", Journal of Powder Engineering Research Association, Vol. 6, No. 1, 1969, pp. 3-8 Non-Patent Literature 2: Ryuichi Aoki, "On the Friction Angle of Powder Particles", Chemical Engineering, Vol. 24, No. 8, 1960, pp. 598-600 Non-Patent Literature 3: Sato et al., Kawasaki Steel Technical Report, vol.29 (1997), pp.30-36 Summary of the Invention

[0007] (The problem the invention aims to solve) However, Patent Document 1 or 2 only focuses on the gas flow rate of the furnace gas injection nozzle (hereinafter also referred to as the SGI nozzle) to suppress fluidization, without fully investigating the influence of other blast furnace conditions, such as the shape of the SGI nozzle or the properties of the filler particles constituting the filler layer. Therefore, even for filler layers with conditions significantly different from those in Patent Document 1 or 2, applying the method of Patent Document 1 or 2 to control the gas flow rate can still predict the fluidization of filler particles, thus leaving room for improvement.

[0008] In view of the above-mentioned problems, the object of the present invention is to provide a method for processing a filling layer that can suppress the flow of filling particles even when gas is supplied from the side of the container to the filling layer under various conditions. (Technical means to solve the problem)

[0009] To address the aforementioned issues, the inventors conducted in-depth research and obtained the following insights. By ensuring that four parameters—the vertical length DT of the nozzle orifice of the nozzle located on the side of the cylindrical container, the harmonic mean particle diameter DP of all filler particles constituting the filler layer, the horizontal blowing pressure Pinj of the gas supplied from the nozzle at the nozzle's height position, and the horizontal powder pressure Ph of the filler layer—satisfy a predetermined relationship, the flowability of the filler particles can be suppressed. Furthermore, Pinj and Ph can be calculated using predetermined formulas based on the characteristic values ​​of the filler particles and the characteristic values ​​of the gas blown in from the nozzle.

[0010] That is, the essential structure of this invention is as follows.

[0011] [1] A method for processing a filling layer, wherein the filling layer is housed in a cylindrical container, characterized in that, The procedure is performed under the condition that the filling layer is contained in the cylindrical container, and the first gas is supplied into the cylindrical container from a nozzle provided on the side of the cylindrical container. DT / DP≦12×(Pinj / Ph)-0.21...(1) Here, DT: Vertical length of the nozzle orifice (m) of the above-mentioned nozzle. DP: Harmonized average particle size (m) of all filling particles constituting the above-mentioned filling layer. Pinj: The horizontal blowing pressure (Pa) of the first gas at the height position of the nozzle mentioned above. Ph: The horizontal powder pressure (Pa) of the filler layer at the height position of the nozzle.

[0012] [2] As described in [1] above, the filling layer processing method, wherein the blower pressure Pinj and the powder pressure Ph are calculated based on the following formulas (2) to (5), [Number 1] [Number 2] [Number 3] [Number 4] Here, ABF: The area (m2) of the horizontal cross-section of the cylindrical container at the height position between the nozzle and the upper surface of the filler layer. PBF: The circumference (m) of the horizontal cross-section of the cylindrical container at a height position midway between the nozzle and the upper surface of the filler layer. h: The distance (m) from the height of the nozzle to the height of the upper surface of the filler layer. ρp: The average total density of all the above-mentioned filling particles (kg / m3) ε: The average porosity of the above-mentioned filling layer (-) ϕ i: The average internal friction angle (°) of all the filling particles mentioned above. k: Average active powder pressure coefficient of all the above-mentioned filler particles (-) x: The penetration distance (m) of the first gas mentioned above. cw: The wall friction coefficient of all the above-mentioned filling particles (-) uh: Horizontal gas velocity (m / s) of the above nozzle. UV: The vertical upward gas velocity (m / s) inside the cylindrical container at the height of the nozzle mentioned above. ρsgi: Density of the first gas mentioned above (kg / m3) μsgi: Viscosity of the first gas mentioned above (Pa·s) ρbf: The average gas density (kg / m3) inside the cylindrical container described above. μbf: Average gas viscosity (Pa·s) inside the aforementioned cylindrical container. f: The average shape factor of all the above-mentioned filling particles (-) g: acceleration due to gravity (m / s²) g': Apparent gravitational acceleration (m / s2) inside the aforementioned cylindrical container.

[0013] [3] As described in [1] or [2] above, the filling layer processing method is to supply gas through a supply port located at the bottom of the cylindrical container to generate a second gas rising inside the cylindrical container.

[0014] [4] The method of processing the filling layer as described in any of [1] to [3] above, wherein the cylindrical container is a blast furnace. (Compared to the effectiveness of previous technologies)

[0015] According to the filling layer processing method of the present invention, when gas is supplied to the filling layer from the side of the container, the flow of filling particles can be suppressed. Simple Explanation of the Diagram

[0016] Figure 1 is a schematic diagram of the cylindrical container used in an embodiment of the present invention. Figure 2 is a schematic diagram of the operation method of a blast furnace when the cylindrical container is a blast furnace in one embodiment of the present invention. Figure 3 is a diagram showing the relationship between DT / DP and Pinj / Ph in an embodiment of the present invention. Figure 4 is a graph showing the relationship between DT / DP and Pinj / Ph in the calculation results when the present invention is applied to a blast furnace. Implementation

[0017] The following describes an embodiment of the method for processing the filling layer housed within a cylindrical container according to the present invention. Furthermore, the embodiments described below are merely examples embodying the present invention and are not intended to limit the scope of the invention.

[0018] Generally, known physical phenomena are described by using appropriately dimensionless parameters, rather than specific physical quantities themselves (e.g., gas flow rate or nozzle diameter), to represent generalized phenomena applicable to a wide range of objects, independent of the size or properties of the apparatus, operating conditions (flow rate, temperature, pressure, etc.). This is known as the similarity rule, a commonly used evaluation method when reproducing large-scale equipment such as blast furnaces, which are difficult to measure, using a scaled-down cold-cell model. Based on various experimental results using cylindrical containers, the inventors investigated whether the flow phenomenon of packed particles can be described by dimensionless parameters, independent of apparatus size, particle properties, gas properties, or operating conditions.

[0019] Furthermore, in this invention, the fluidization state of the filler particles is defined as follows. When gas is blown into the filler layer from a nozzle installed in a cylindrical container, the filler particles remain stationary under low gas flow conditions, but begin to move as the gas flow rate increases. In this invention, the state in which the innermost region of the cavity formed in front of the nozzle orifice of the nozzle in the cylindrical container (hereinafter also referred to as the fluidization depth) reaches more than three times the harmonic mean particle size (DP) of the filler particles is considered to be the fluidization state of the filler particles. When the fluidization depth reaches more than three times the harmonic mean particle size (DP), the exchange between the upper and lower filler particles becomes intense, thus increasing the possibility of structural collapse of the filler layer. In a filler layer where filler particles descend uniformly like in a blast furnace, the exchange between the upper and lower filler particles makes the descent of the filler particles unstable, thereby adversely affecting operation. Therefore, the fluidization depth needs to be maintained at less than three times the harmonic mean particle size (DP). Furthermore, under the condition of fluidized filler particles, it is assumed that the filler particles rotate in the raceway area in front of the tuyeres of the blast furnace, but it is not limited to this situation.

[0020] The inventors conducted in-depth research and found that when the horizontal blowing pressure of the first gas at the height of the nozzle significantly exceeds the horizontal powder pressure of the filler layer at the height of the nozzle, the filler particles will flow. Furthermore, in addition to the above, it was also found that the flow behavior is affected not only by the flow rate of the first gas blown in from the nozzle on the side of the container, but also by the vertical length of the nozzle orifice of the nozzle into which the first gas is blown in. Based on these findings, conditions applicable to a wide range of filler particles were investigated, and it was found that by processing the filler layer under the conditions satisfying the following formula (1), the flow of the filler particles can be prevented. DT / DP≦12×(Pinj / Ph)-0.21…(1) Here, DT: Vertical length of the nozzle orifice (m) of the above-mentioned nozzle. DP: Harmonized average particle size (m) of all filling particles constituting the above-mentioned filling layer. Pinj: The horizontal blowing pressure (Pa) of the first gas at the nozzle height position. Ph: The horizontal powder pressure (Pa) of the packing layer at the nozzle height position.

[0021] Furthermore, the lower limit of DT / DP in the above formula (1) is not specifically limited, but in order to prevent the pressure loss at the nozzle from becoming too high, DT / DP is preferably above 1.

[0022] In equation (1) above, if Pinj / Ph is not 0 due to reasons such as g' becoming negative (described later), the right side of equation (1) will not be a real number, and the filling layer cannot be processed under the condition of satisfying equation (1). That is, in this case, the provisions of the present invention are not satisfied, and the scope of the present invention is exceeded. Furthermore, since the first gas is supplied to the cylindrical container from the nozzle, the present invention does not assume that Pinj / Ph is 0. Therefore, Pinj / Ph is set to be greater than 0, preferably 0.1 or more. On the other hand, there is no particular limit to the upper limit of Pinj / Ph, and Pinj / Ph is approximately 1000 or less.

[0023] [cylindrical container] The following will explain the structure of a cylindrical container that satisfies the premise of the above formula (1).

[0024] In one embodiment of the present invention, a cylindrical container is used to house a filling layer inside, has a supply port at the bottom, and a nozzle at the side. Figure 1 is a schematic diagram showing the cylindrical container 100 used in an embodiment of the present invention. With the filling layer 10 housed inside the cylindrical container 100, a first gas 14 is supplied into the cylindrical container 100 through a nozzle 12 located on the side of the cylindrical container 100. Furthermore, gas can be blown into the cylindrical container 100 through a supply port 16 located at the bottom of the cylindrical container 100 to generate a second gas 18 that rises within the cylindrical container. During processing, a vibrating feeder 20 located at the bottom of the cylindrical container 100 discharges 22 of the filling particles constituting the filling layer 10 at a constant speed, causing the raw material particles to fall. At this time, by periodically replenishing 24 of the filling particles from the upper part of the cylindrical container 100, the height of the filling layer 10 can be kept constant.

[0025] The maximum height of the packing layer 10 stored inside the cylindrical container 100 is used as the reference height, and the nozzle 12 is installed at a position lower than the reference height. The value obtained by dividing the distance from the reference height to the nozzle 12 installation height by the distance from the reference height to the supply port 16 is preferably 0.1 or higher and 0.9 or lower. By setting this value to 0.1 or higher, the flow and bypassing of packing particles on the surface of the packing layer 10 can be better suppressed. On the other hand, by setting this value to 0.9 or lower, the introduction of the first gas 14 before the second gas 18 diffuses to the furnace wall of the cylindrical container 100 can be better suppressed. Furthermore, the cylindrical container 100 is preferably installed such that the axis of the height direction of the cylindrical container 100 is parallel to the vertical direction. Also, the cross-sectional shape of the cylindrical container is not particularly limited; for example, a cylindrical container with a cylindrical cross-section can be used.

[0026] A blast furnace is an example of a cylindrical container with this structure. In one embodiment of the invention, a blast furnace is preferred as the cylindrical container. The conditions for applying the invention to a blast furnace will be described later. Furthermore, besides blast furnaces, the invention can be applied to any situation where processing is carried out using a shaft furnace or similar structure that allows gas to be blown in from the side and bottom of the cylindrical container.

[0027] Figure 2 is a schematic diagram illustrating the operation method of a blast furnace when the cylindrical container is a blast furnace in one embodiment of the present invention. The blast furnace 102 is filled with raw material particles 30, and an SGI nozzle 32 is provided in the furnace body. A tuyeres 34 for blowing in oxygen-containing gas and reducing materials are provided at the bottom. During the operation of the blast furnace 102, the first gas is SGI gas 36 supplied from the SGI nozzle 32, and the second gas is furnace belly gas 38 rising from the bottom of the blast furnace. Furthermore, molten pig iron 40 can be removed from the bottom of the blast furnace 102 during the processing.

[0028] The filler particles that make up the filling layer inside the cylindrical container can be appropriately selected by the operator according to the type or purpose of the cylindrical container. The filling layer can be composed of several types of filler particles.

[0029] When the cylindrical container is a blast furnace, the packing layer can be made of ferrous raw materials (iron ore, sintered iron ore, granulated iron ore, reduced iron, etc.) and reducing materials (coke, etc.). The particle size of the raw materials constituting the packing layer can be appropriately selected according to the size of the cylindrical container. For example, for a blast furnace with a height of 10 m and an internal diameter of 3 m, the average particle size can be set to 10 mm or more and 50 mm or less. Furthermore, when the cylindrical container is a blast furnace, the average total density of the packing layer is preferably 500 kg / m³ or more and 1810 kg / m³ or less.

[0030] [Gas 1 and Gas 2] As described later, the first gas supplied from the nozzle to the cylindrical container and the second gas rising within the cylindrical container can be air or the like. From the viewpoint of preventing condensation within the packing layer, the temperatures of the first and second gases are preferably high enough to prevent condensation, for example, 15°C or higher. Furthermore, from the viewpoint of a protective device, the temperature of the first gas is preferably below the heat resistance temperature of the device, for example, 60°C or lower when the cylindrical container is made of vinyl chloride.

[0031] When the cylindrical container is a blast furnace, granular ore and coke are charged from the top of the blast furnace, and oxygen-containing gas and reducing materials (methane gas, etc.) are blown in through the tuyeres 34 located at the bottom of the blast furnace. When the present invention is applied to a blast furnace, the gas that rises from the bottom of the blast furnace and reduces the ore (hereinafter also referred to as the furnace belly gas) is the second gas, and the high-temperature gas (hereinafter also referred to as the SGI gas) blown in through the nozzles (SGI nozzles 32) located in the furnace body is the first gas.

[0032] From the viewpoint of not hindering the reduction reaction of iron-based raw materials in the blast furnace, the SGI gas is preferably a gas containing at least one of carbon monoxide and hydrogen. Furthermore, since it is necessary to supply gas from the nozzle at the same temperature as the gas rising from the furnace belly to the nozzle position, the temperature of the SGI gas is preferably 400°C or higher. Moreover, from the viewpoint of preventing energy loss due to overheating of the gas, the temperature of the SGI gas is preferably below 1200°C, and more preferably below 1000°C.

[0033] The blast gas supplied to the tuyeres of the blast furnace is air or oxygen-containing gas. From the viewpoint of reducing CO2 emissions, oxygen is preferable. Similarly, from the viewpoint of reducing CO2 emissions, the reducing feedstock blown into the tuyeres is preferably a hydrogen-based reducing gas such as methane. From the viewpoint of ensuring the gas temperature at the tuyeres, the temperature of the gas supplied to the tuyeres is preferably above 0°C. Furthermore, from the viewpoint of preventing excessive temperature rise of the gas at the tuyeres, the temperature of the gas supplied to the tuyeres is preferably below 1300°C.

[0034] The blast furnace gas system consists of the blast air supplied to the tuyeres and the reducing gases (CO, H2, N2, etc.) generated from the reaction of the reducing raw materials blown into the tuyeres with the coke at the front of the tuyeres. From the viewpoint of promoting the reduction reaction of the ore, the temperature of the blast furnace gas at the nozzle height is preferably set to 560°C or higher. Furthermore, from the viewpoint of preventing softened molten ore from adhering to the nozzle, the temperature of the blast furnace gas at the nozzle height is preferably set to 1200°C or lower.

[0035] [nozzle] Next, the nozzles provided on the side of the cylindrical container will be described. If the number of nozzles provided on the side of the cylindrical container is one or more, the injection rate of the first gas can be better maintained, and the flow of the filling particles can be better suppressed. On the other hand, if the number of nozzles is 100 or less, equipment costs or maintenance and management costs can be better reduced, and operation can be carried out efficiently. Therefore, the number of nozzles is preferably 100 or less, and more preferably 50 or less. Furthermore, when multiple nozzles are provided, nozzles at the same height position on the side of the cylindrical container are preferably provided at equal intervals along the circumference of the cylindrical container. The same applies when the nozzles are divided into multiple segments in the height direction as described later.

[0036] Furthermore, the nozzle does not necessarily have to be horizontally positioned; it can also be positioned at an angle relative to the side of the cylindrical container. When the nozzle is positioned at an angle relative to the side of the cylindrical container, the nozzle height is set to the height of the nozzle tip.

[0037] Furthermore, when multiple nozzles are provided, although all nozzles can be positioned at the same height, it is not necessary to position all nozzles at the same height; nozzles can also be arranged in multiple segments. For example, the nozzles can be arranged in a staggered configuration of two or more segments. When nozzles are arranged in multiple segments, the present invention can be applied to each nozzle separately. Moreover, when the conditions of the present invention are met in all nozzles, it is determined that there is no flow.

[0038] The cross-sectional shape of the nozzle orifice perpendicular to the gas injection direction (i.e., the nozzle orifice shape) is not limited to a circle; for example, it can also be rectangular. Regardless of the shape, the maximum vertical length of the nozzle orifice is defined as DT. Examples of a rectangular nozzle orifice include nozzles with slit-like tips, and there can be multiple slits. Furthermore, the nozzle is not limited to a single-hole nozzle; multi-hole nozzles can also be used. As a multi-hole nozzle, a nozzle with multiple equally spaced and closely spaced discharge holes can be used. For example, a multi-hole nozzle can be formed by bundling multiple tubes together, a multi-hole nozzle tip can be attached to the front end of a single tube, or a multi-hole nozzle can be formed by setting a mesh on a single-hole nozzle. When using a multi-hole nozzle, the vertical length DT of the nozzle orifice is defined as the length from the lowest point of the lowermost nozzle to the highest point of the uppermost nozzle among the multiple discharge holes of the multi-hole nozzle in the vertical direction. Furthermore, when using a multi-hole nozzle, it achieves the effect of preventing filler particles from entering the nozzle. Moreover, when multiple nozzles are provided, the cross-sectional shape of the nozzles can be different for each nozzle; preferably, all nozzles should have the same cross-sectional shape. Also, when the cross-sectional shapes of the nozzles are different, the present invention can be applied to each nozzle separately. Furthermore, when all nozzles meet the requirements of the present invention, it is determined that there is no flow.

[0039] [DT] If the vertical length DT of the nozzle orifice is DP or more, the pressure drop of the nozzle will be kept low and the first gas will be diffused appropriately. Therefore, DT is preferably more than 1 times DP. For example, when DP is 0.02 m, DT is preferably 0.02 m or more. On the other hand, if DT is less than 10 times DP, the backflow of filler particles in the filler layer towards the nozzle can be appropriately prevented. Therefore, DT is preferably less than 10 times DP, and more preferably less than 5 times DP. For example, when the blended average particle size DP of all filler particles is 0.02 m, DT is preferably less than 0.20 m, and more preferably less than 0.10 m.

[0040] Furthermore, although the above formula (1) is better used when determining DT in the design of cylindrical containers, when it is difficult to adjust DT, the operating conditions can be determined by adjusting DP, Pinj, and Ph.

[0041] [DP] If the harmonic average particle size (DP) of all the filler particles constituting the filler layer is 0.001 μm or more, the air resistance of the filler layer can be kept low, and the gas can flow stably without causing the filler particles to flow or penetrate. Therefore, DP is preferably 0.001 μm or more. On the other hand, if DP is 0.050 μm or less, heat transfer or reaction between the gas and the filler particles can occur without delay. Therefore, DP is preferably 0.050 μm or less.

[0042] The blended average particle size DP of all the filling particles constituting the filling layer can be determined as follows. First, a 1 kg powder sample of particles filled in a cylindrical container is taken and dried. Then, the powder sample is sieved in order of mesh size (0.25, 0.5, 1, 2, 4, 8, 16, 31.5, 63, and 125 mm) and the weight ratio of each particle size is determined. Based on the measurement results, the blended average particle size DP is determined by the following formula (6). [Number 5] Here, i is an integer from 1 to 10, the weight ratio of the i-th particle size range separated by the above sieves is set as wi, and the representative particle size is set as xi.

[0043] Furthermore, in the above measurements, the representative particle size xi for each particle size range is set as the geometric mean of the larger and smaller mesh sizes, respectively. Also, to suppress the flowability of the filler particles, microparticles with a particle size of 0.25 mm or smaller are generally removed from the filler particles used in the filler layer beforehand. Therefore, the microparticles smaller than 0.25 mm contained in the filler particles are trace amounts and can be ignored. Furthermore, for particles with a particle size of 125 mm or larger, the geometric mean of 125 mm and the largest particle size among the samples is used as the representative particle size. When the filler layer consists of multiple particle types, the harmonic mean particle size of each particle type is measured, and a weighted arithmetic mean is calculated using the mixing ratio (bulk volume ratio) of each particle type in the filler layer. This average value is set as Dp.

[0044] [Pinj] If the horizontal blowing pressure Pinj of the first gas at the nozzle height position is 0.1 kPa or more, the effect of suppressing particle intrusion into the nozzle can be achieved. Therefore, Pinj is preferably 0.1 kPa or more. On the other hand, if Pinj is 40000 kPa or less, the pressure loss of the nozzle can be suppressed to a low level. Therefore, Pinj is preferably 40000 kPa or less. Furthermore, since Pinj is difficult to calculate directly, it is preferable to use formula (2).

[0045] [Ph] If the horizontal powder pressure Ph of the packing layer at the height of the nozzle is 0.1 kPa or more, sudden penetration caused by changes in gas flow rate within the packing layer can be suppressed. Therefore, Ph is preferably 0.1 kPa or more. On the other hand, if Ph is 50 kPa or less, pulverization of the particles constituting the packing layer can be suppressed. Therefore, Ph is preferably 50 kPa or less. Furthermore, Ph can be calculated using equation (3), or it can be directly measured by installing a load cell on the inner wall of the cylindrical container.

[0046] The inventors conducted further detailed investigations, and the results allowed for a more precise estimation of Ph and Pinj, and established a method for predicting with high accuracy whether fluidization of the filling particles occurs. Specifically, Pinj and Ph can be represented by the following equations (2) and (3), respectively. [Number 6] [Number 7]

[0047] The following will explain the definitions of the various coefficients used in equations (2) and (3) and the methods for obtaining them.

[0048] [ABF] The area of ​​the horizontal cross-section of the cylindrical container at a height between the nozzle and the upper surface of the filler layer is defined as ABF (m2). Furthermore, when the nozzle is divided into multiple segments along the height direction, ABF (m2) is obtained for each nozzle. In this case, the present invention is applied to each nozzle individually, and when the conditions of the present invention are met in all nozzles, it is determined that there is no flow. The same applies below.

[0049] [PBF] The circumference of the cylindrical container, which is the horizontal cross-section of the cylindrical container at the height position between the nozzle and the upper surface of the filler layer, is defined as PBF (m). Furthermore, when the nozzle is divided into multiple segments in the height direction, PBF (m) is obtained for each nozzle.

[0050] [h] The distance from the height of the nozzle to the height of the upper surface of the filler layer is defined as h (m). Furthermore, when the upper surface of the filler layer is not horizontal, the height of the upper surface of the filler layer at the wall above the nozzle is used. Furthermore, when the nozzle is divided into multiple segments in the height direction, h (m) is obtained for each nozzle.

[0051] [ρp] The average total density of all filler particles constituting the filler layer is defined as ρp (kg / m3). ρp can be calculated as follows: Fill a container with filler particles to a size sufficiently large than the average particle size of the filler particles (e.g., the inner diameter and height are approximately 20 times the harmonic average particle size of the filler particles). Measure the weight of the filler particles, and divide the weight of the filler particles by the internal volume of the container; this value is defined as ρp. When the filler layer consists of multiple particle types, measure the total density of each particle type as described above, and calculate the weighted arithmetic mean based on the mixing ratio (total volume ratio) of each particle type in the filler layer; this average value is defined as ρp.

[0052] [ε] The average porosity of the filling layer is set as ε(-). ε can be obtained as follows. First, the apparent density ρ of the filling particles is measured by liquid weighing or the like. When the filling layer is composed of multiple particle types, the apparent density of each particle type is measured, and the weighted arithmetic mean is calculated based on the mixing ratio of each particle type in the filling layer (apparent volume ratio, apparent volume ratio of each particle type = weight of each particle type in the filling layer / apparent density of each particle type). The obtained average value is set as ρ. Then, based on the obtained ρ and the above ρp, ε is obtained using the following formula (7). ε=1-ρp / ρ ...(7)

[0053] [ϕ i] The average internal friction angle of all the filling particles constituting the filling layer is denoted as ϕi (°). ϕi can be measured using the shear test apparatus described in Non-Patent Document 1. Furthermore, when the filling layer is composed of multiple particle types, the internal friction angle of each particle type is measured, and a weighted arithmetic mean is calculated based on the mixing ratio (total volume ratio) of each particle type in the filling layer. The resulting average value is denoted as ϕi.

[0054] [k] Let k be the average active powder pressure coefficient of all the filling particles constituting the filling layer. k can be obtained by using the above ϕ i and by the following equation (4). [Number 8]

[0055] [x] The upper limit of the penetration distance of the first gas is set as x (m). x is the state of the fluidized state of the filling particles, which is three times the harmonic average particle size DP. The state of the fluidized state of the filling particles is as described above.

[0056] [cw] The average wall friction coefficient of all filling particles constituting the filling layer is set as cw(-). cw can be obtained as follows. The wall friction angle ϕw is obtained using the method described in Non-Patent Document 2, and the wall friction coefficient cw is calculated using the following formula (8). Furthermore, when the filling layer is composed of multiple particle types, the wall friction coefficient of each particle type is obtained, and the weighted arithmetic mean is obtained based on the mixing ratio (total volume ratio) of each particle type in the filling layer. The obtained average value is set as cw. cw=tan(ϕ w) ...(8)

[0057] [uh] Let the horizontal gas flow velocity of the nozzle be uh (m / s). uh can be calculated as follows. The gas flow rate V1N (Nm3 / h) of the first gas blown into each nozzle is corrected for by the blowing temperature and pressure of the first gas, and the temperature and pressure corrected flow rate V1 is calculated. Then, uh is calculated by dividing the temperature and pressure corrected flow rate V1 by the cross-sectional area of ​​the nozzle orifice. Specifically, the temperature and pressure corrected flow rate V1 (m3 / h) can be calculated using the gauge pressure P1 (PaG) and gas temperature T1 (°C) of the first gas at the nozzle position, and by the following formula (9). V1=V1N×{(273.15+T1) / 273.15}×{101325 / (101325+P1)} …(9)

[0058] Furthermore, regarding the gauge pressure P1 and gas temperature T1 of the first gas used in the above correction, it is preferable to directly measure them by installing a pressure gauge and a thermometer at the nozzle position. When direct measurement is difficult, a pressure gauge and a thermometer can be installed on the upstream piping of the nozzle, or the value of the pressure gauge on the blast furnace wall near the nozzle can be used instead of the nozzle pressure value. Alternatively, the pressure and temperature at the nozzle position can be calculated and used through numerical simulation. Furthermore, when using nozzles with different cross-sectional shapes, the horizontal gas flow velocity of each nozzle may be different. When the horizontal gas flow velocity of each nozzle is different, it is sufficient to measure the flow rate of each nozzle to obtain the flow rate of each nozzle. In this case, the temperature and pressure correction flow rate of each nozzle can be divided by the cross-sectional area of ​​its respective nozzle to calculate uh, and the presence or absence of flow can be evaluated separately using Equation (1). Furthermore, when the nozzle is not horizontally set, the flow velocity of the first gas is taken as a vector in the same direction as the discharge direction from the nozzle, and its horizontal component is set as uh.

[0059] [uv] The vertical upward gas velocity in the cylindrical container at the height of the nozzle is defined as uv (m / s). uv can be calculated as follows. Based on the total flow rate V2N (Nm3 / h) of the first and second gases blown into the container, the temperature and pressure corrected flow rate V2 (m3 / h) is calculated, which is corrected for the average gas temperature and average pressure in the cylindrical container between the height of the nozzle and the height of the upper surface of the packing layer. The temperature and pressure corrected flow rate V2 is divided by the cross-sectional area of ​​the cylindrical container at the height position between the nozzle and the upper surface of the packing layer to calculate uv (m / s). Specifically, the temperature and pressure corrected flow rate V2 (m3 / s) can be calculated using the average gauge pressure P2 (PaG) and the average gas temperature T2 (°C) between the height of the nozzle and the height of the upper surface of the packing layer, and by the following formula (10). Furthermore, when the nozzle is divided into multiple segments in the height direction, uv (m / s) is calculated for each nozzle. V2=V2N×{(273.15+T2) / 273.15}×{101325 / (101325+P2)} …(10)

[0060] Furthermore, regarding the average gauge pressure P2 and average gas temperature T2 used in the aforementioned corrections, a thermometer and a pressure gauge can be installed inside the cylindrical container at a height between the nozzle and the upper surface of the packing layer, and their measured values ​​can be used as the average gauge pressure P2 and average gas temperature T2. The thermometer and pressure gauge are preferably installed near the center of the cylindrical container, but if this is difficult, they can be installed near the wall. Alternatively, the pressure and temperature at this location inside the cylindrical container can be calculated using numerical simulation.

[0061] [ρsgi] Let the density of the first gas be ρsgi (kg / m3). ρsgi can be calculated based on the composition, temperature, and pressure of the first gas using the gas law.

[0062] [μsgi] Let the viscosity of the first gas be μsgi (Pa·s). The viscosity values ​​of pure gases can be obtained from various literature (e.g., science timelines). To calculate μsgi, first, obtain the viscosity values ​​of each pure gas at the temperature of the first gas. Then, based on the composition of the first gas, calculate the viscosity by weighting the viscosity values ​​of each pure gas according to the mixing ratio (volume ratio).

[0063] [ρbf] The average gas density inside the cylindrical container is defined as ρbf (kg / m³). ρbf can be calculated using the equation of state for the mixture of the first and second gases at the nozzle height, based on the gas composition, temperature, and pressure. Furthermore, when only the first gas is blown in, the flow rate of the second gas is set to zero for calculation.

[0064] [μbf] The average gas viscosity inside the cylindrical container is set as μbf (Pa·s). μbf can be calculated by obtaining the viscosity value of the pure gas species at the temperature of the second gas in the same way as the viscosity μsgi of the first gas, and by weighting the average based on the mixing ratio (volume ratio) according to the composition of the second gas.

[0065] Furthermore, when the treatment of the packing layer involves a reaction, the composition and mole number of the gas inside the cylindrical container change during the treatment process. Therefore, it is preferable to calculate the various characteristic values ​​of the gas inside the cylindrical container by considering the changes in gas composition and mole number during the treatment process through reaction calculations, etc., so that more detailed calculations can be performed. For example, when the cylindrical container is a blast furnace, the blown air (air, oxygen, etc.) from the tuyere, the reducing materials (methane gas, pulverized coal, etc.) from the tuyere, and the coke present in the furnace react near the tuyere to generate a belly gas mainly composed of carbon monoxide and hydrogen. This belly gas rises in the blast furnace and affects the flow behavior near the nozzles in the furnace body. Therefore, when the cylindrical container is a blast furnace, it is preferable to use the belly gas reacted near the tuyere as the second gas.

[0066] [f] The average shape factor of all the filling particles constituting the filling layer is set as f(-). f can be obtained as follows. Prepare a container into which gas can be introduced at a uniform flow rate, and fill the container with the filling particles of the object to be measured. Furthermore, the cross-sectional area of ​​the container is set to be sufficiently large than the average particle size of the filling particles (for example, about 20 times the average particle size). Allow the gas to flow in the container, and measure the pressure at two observation points along the gas flow direction. Based on the differential pressure ΔP obtained from the measurement results and the distance L between the observation points, calculate the shape factor using the following equation (11) (the so-called Ergun's equation). Furthermore, the methods for obtaining ε, μbf, μv, Dp, and ρbf in equation (11) are as described above, using values ​​related to the filling particles to be measured and the gas used in the measurement. When the filling layer is composed of multiple particle types, the shape coefficient of each particle type is determined as described above, and the weighted arithmetic mean is calculated based on the mixing ratio (total volume ratio) of each particle type in the filling layer. The resulting average value is set as f. [Number 9]

[0067] [g] Let the acceleration due to gravity be g (m / s2).

[0068] [g'] Through repeated and meticulous experiments with varying gas and particle conditions, the inventors have discovered that even with the same nozzle shape and gas flow rate, the greater the velocity of the rising gas within the cylindrical container, the easier it is for fluidization to occur near the nozzle. Further detailed investigation yielded the following insight: The rising gas within the cylindrical container reduces the gravitational acceleration acting on the apparent filling particles, thereby reducing powder pressure. Therefore, by using an apparent gravitational acceleration g' that takes into account the influence of the vertically upward gas flow rate uv within the cylindrical container, the presence or absence of fluidization can be precisely predicted even when rising gas is present within the cylindrical container.

[0069] g' can be obtained using the above value according to the following equation (5). Furthermore, in equation (5), when the gas velocity in the vertical direction is extremely high, g' may become a negative value. In this case, since the right side of equation (1) is not a real number, it is impossible to perform the filling layer processing under the condition of satisfying equation (1), which is beyond the scope of the present invention. [Number 10]

[0070] Furthermore, when the cylindrical vessel is a blast furnace, if the heat flow ratio is 1.1 or less, insufficient heating of the raw materials inside the blast furnace can be prevented. Therefore, the heat flow ratio is preferably 1.1 or less, more preferably 1.0 or less, and even more preferably 0.9 or less. On the other hand, if the heat flow ratio is 0.4 or more, the furnace top temperature will not rise excessively, and the failure of the furnace top equipment can be better suppressed. Therefore, the heat flow ratio is preferably 0.4 or more, and even more preferably 0.6 or more. Moreover, the heat flow ratio (Ws / Wg) is a value calculated by the following formula (12). [Number 11] Here, Cp,c, Cp,o, and Cp,g are the specific heats of coke, ore, and gas, respectively; CR is the coke ratio (kg / molten pig iron-ton); OR is the ore ratio (kg / molten pig iron-ton); BV is the furnace belly gas consumption rate (Nm3 / molten pig iron-ton); and BSGI is the consumption rate of the first gas blown in from the nozzle (total flow rate of all nozzles) (Nm3 / molten pig iron-ton).

[0071] Furthermore, for steps and conditions not described in this instruction manual, conventional methods may be used. [Example]

[0072] <Example 1: An experiment conducted using a cold model apparatus> Using a cold model device as a cylindrical container, gas is supplied from the bottom of the cylindrical container to generate a second gas that rises inside the cylindrical container, and a first gas is supplied from a nozzle on the side of the cylindrical container to investigate the conditions under which the fluidization of the filling particles occurs.

[0073] Figure 1 shows a schematic diagram of the cylindrical container 100 used. The cylindrical container 100 is a scaled-down model device simulating a blast furnace, and its structure is as described above. The cylindrical container 100 is a cylindrical container with an opening radius of 281 mm and a furnace height of 1570 mm, symmetrically cut into a 20° section along the circumference. That is, the ABF of the cylindrical container used is 0.01378 m2, and the PBF is 0.6601 m. Furthermore, the cylindrical container 100 is a transparent vinyl chloride container so that the flow behavior of the packed particles can be observed.

[0074] As shown in Figure 1, a nozzle 12 is provided on the side (circumferential side) of the cylindrical container 100. The nozzle orifice of the nozzle 12 is semi-circular, and two nozzles are arranged horizontally (0°) at a height of 605 mm from the supply port 16 located at the lower part of the cylindrical container. A camera (not shown) is installed on the side of the cylindrical container 100 to observe the flow of the filling particles in front of the nozzle 12. The semi-circular radius of the nozzle orifice profile (equivalent to the vertical length DT of the nozzle orifice) is varied within the range of 7.4 to 14 mm to conduct the following tests.

[0075] Both the first and second gases are air at room temperature (25°C) and atmospheric pressure (101325 Pa). That is, air is supplied to both nozzle 12 and supply port 16. Therefore, the density ρsgi of the first gas and the average gas density ρbf inside the cylindrical container are the same value. Similarly, the viscosity μsgi of the first gas and the average gas viscosity μbf inside the cylindrical container are also the same value. The flow rate of the second gas varies from 0 to 371 NL / min, and the flow rate of the first gas varies from 8.7 to 1559.9 NL / min. The height of the upper surface of the packing layer varies from 200 to 610 mm above the height of the nozzle.

[0076] Four types of particles were prepared as filling materials for the cylindrical container: colored sand (mixed average diameter 1.7 mm, total density 1501 kg / m3), sinter 1 (mixed average diameter 1.7 mm, total density 2198 kg / m3), sinter 2 (mixed average diameter 3.4 mm, total density 2229 kg / m3), and polymer particles (mixed average diameter 3.44 mm, total density 628 kg / m3).

[0077] Assuming the raw material particles are descending within the blast furnace, a vibrating feeder at the bottom of the cylindrical container discharges the filler particles at a constant speed, while simultaneously replenishing particles from the top of the cylindrical container. By adjusting the discharge and replenishment rates of the filler particles, the height of the upper surface of the filler layer is kept constant.

[0078] Table 1 shows the experimental conditions and results for each example. During the experiment, a measuring scale mounted on the apparatus was used to measure the fluidization depth. In cases where a cavity with a diameter greater than three times the harmonic average diameter of the filling particles was confirmed, the filling particles were determined to be fluidized, and the case was marked "Yes" in the column indicating whether fluidization occurred in Table 1. On the other hand, in cases where fluidization of the filling particles was not confirmed, the case was marked "No" in the column indicating whether fluidization occurred in Table 1.

[0079] Figure 3 shows the results of observing whether fluidization of the filling particles occurred and plotting the relationship between DT / DP and Pinj / Ph. In Figure 3, “╳” is drawn for each example when fluidization occurred and “○” is drawn for the example when it did not occur. Furthermore, the lines in Figure 3 represent the equality of Equation (1). It can be confirmed that even when the particle properties of the filling layer (harmonic average particle size Dp, average total density ρp, average porosity ε, average shape factor f, average internal friction angle ϕi, average wall friction coefficient cw), the vertical length of the nozzle orifice, the first gas flow rate, the second gas flow rate, and the height position of the upper surface of the filling layer are changed, fluidization will not occur when the conditions of Equation (1) of the present invention are met (the area further to the lower left than the line shown in Figure 3), but fluidization will occur when the conditions of Equation (1) are not met (the area further to the upper right than the line shown in Figure 3). Furthermore, for No. 68 (comparative example) in Table 1, since the right side of equation (1) is not a real number, it is not drawn in Figure 3, but in this case, it can still be confirmed that flow has occurred. Therefore, it can be confirmed that the present invention is applicable regardless of the device size, particle properties, gas properties, or operating conditions.

[0080] [Table 1]

[0081] <Example 2: Applicable to large blast furnaces> Example 2 evaluates the application of the present invention to a large blast furnace. It is assumed that the applicable blast furnace is 4300 m³. It is assumed that the SGI nozzles installed in the blast furnace have a circular cross-section, are all positioned at the same height (one segment), and are evenly spaced along the circumference of the blast furnace.

[0082] The total flow rate of SGI gas blown in from n SGI nozzles is taken as the first gas flow rate. The flow rate of the furnace belly gas generated by the reaction of the blast furnace air (oxygen) blown in from the tuyeres located at the bottom of the blast furnace with the reducing materials (methane, coke) near the tuyeres is taken as the second gas flow rate. The gas density ρbf and gas viscosity μbf of the upward airflow are calculated using the gas composition, furnace temperature, and furnace pressure calculated using the blast furnace numerical simulation model described in Non-Patent Document 3. When calculating the gas density ρbf and gas viscosity μbf, the average value of the area (furnace body) between the SGI nozzle height and the upper surface of the raw material filling is used (furnace body average). Abf, Pbf, and upward gas velocity uv are calculated based on the furnace radius at the midpoint between the SGI nozzle height and the furnace top height. The gas density ρsgi and gas viscosity μsgi of the SGI gas blown in from the SGI nozzle are calculated using the pressure at the height of the SGI nozzle, the composition of the gas blown in from the SGI nozzle, and the gas temperature.

[0083] As for the filler particles, we assume three types: lumpy coke, small lumpy coke, and ore raw materials (sinter). The physical properties of the filler particles (blended average particle size Dp, average total density ρp, average porosity ε, average shape factor f, average internal friction angle ϕi, and average wall friction coefficient cw) are calculated by weighted averaging of the particle properties of each individual particle of the loaded raw material particles (lumpy coke, small lumpy coke, and ore raw materials) according to the volume ratio of the raw material input.

[0084] Table 2 shows the calculation results applicable to blast furnaces. Based on the results, in the fluidization determination column of Table 2, examples that satisfy Equation (1) of the present invention are marked as "None", and examples that do not satisfy it are marked as "Yes". Similarly, for Figure 4, when Equation (1) of the present invention is satisfied, it is determined that no fluidization has occurred and "○" is drawn; when it is not satisfied, it is determined that fluidization has occurred and "╳" is drawn. Furthermore, the lines in Figure 4 represent the equality sign of Equation (1).

[0085] (Industrial applicability)

[0086] According to the present invention, a method for processing a filling layer can be provided that can suppress the flow of filling particles even when gas is supplied from the side of the container to the filling layer under various conditions.

[0087] 10: Fill layer 12: Nozzle 14: First Gas 16: Supply Port 18: Second gas 20: Vibrating feeder 22: Discharge of filling particles 24: Filling Particles 30: Raw material particles 32: SGI nozzle 34: The Opportunity 36: SGI gas 38: Furnace belly gas 40: Molten pig iron 100:Tubular container 102: Blast Furnace

Claims

1. A method for processing a filling layer, wherein the filling layer is contained in a cylindrical container, characterized in that it is performed under the condition of satisfying the following formula (1): in the state where the filling layer is contained in the cylindrical container, a first gas is supplied from a nozzle provided on the side of the cylindrical container to the cylindrical container, DT / DP≦12×(Pinj / Ph)-0.21 …(1) Here, DT: vertical length of the nozzle orifice (m) DP: the average particle size of all filling particles constituting the filling layer (m) Pinj: the horizontal blowing pressure of the first gas at the height position of the nozzle (Pa) Ph: the horizontal powder pressure of the filling layer at the height position of the nozzle (Pa).

2. The method for processing the padding layer as requested in item 1, wherein, The aforementioned blower pressure Pinj and powder pressure Ph are calculated based on the following formulas (2) to (5): [Formula 1] [Formula 2] [Formula 3] [Formula 4] Here, ABF: the area (m2) of the horizontal cross-section of the cylindrical container at the height position between the nozzle and the upper surface of the filling layer PBF: the perimeter (m) of the horizontal cross-section of the cylindrical container at the height position between the nozzle and the upper surface of the filling layer h: the distance (m) from the height position of the nozzle to the height position of the upper surface of the filling layer ρp: the average total density (kg / m3) ε: the average porosity (-) ϕi: the average internal friction angle (°) of all the filling particles k: the average active powder pressure coefficient (-) x: the penetration distance of the first gas (m) cw: the wall friction coefficient (-) uh: the horizontal gas velocity (m / s) of the nozzle uv: Vertical gas velocity (m / s) in the cylindrical container at the height of the nozzle. ρsgi: Density of the first gas (kg / m3). μsgi: Viscosity of the first gas (Pa·s). ρbf: Average gas density (kg / m3) in the cylindrical container. μbf: Average gas viscosity (Pa·s) in the cylindrical container. f: Average shape factor (-) of all filling particles. g: Gravitational acceleration (m / s2). g': Apparent gravitational acceleration (m / s2) in the cylindrical container.

3. The method of processing the filling layer as claimed in claim 1 or 2, wherein gas is supplied from a supply port located at the lower part of the cylindrical container to generate a second gas rising inside the cylindrical container.

4. The method for processing the fill layer as requested in item 1 or 2, wherein, The aforementioned cylindrical container is a blast furnace.

5. The method for handling the padding layer as described in request item 3, wherein, The aforementioned cylindrical container is a blast furnace.

Images