Method for processing a packed bed contained in a cylindrical container

Abstract

Provided is a processing method of a filler layer enabling suppression of fluidization of filler particles. This processing method of a filler layer accommodated in a tubular container is characterized in that a step of supplying a first gas into the tubular container from a nozzle provided on a side part of the tubular container in a state in which the filler layer is accommodated in the tubular container is performed under a condition satisfying the following formula (1).　(1): DT / DP ≤ 12 × (Pinj / Ph)-0.21, where DT is the length (m) in the vertical direction of a nozzle port of the nozzle, DP is the harmonic mean particle diameter (m) of all the filler particles constituting the filler layer, Pinj is the impact wind pressure (Pa) in the horizontal direction of the first gas at the height position of the nozzle, and Ph is the powder pressure (Pa) in the horizontal direction of the filler layer at the height position of the nozzle.

Description

[Technical Field]

[0001] The present invention relates to a method for processing a packed bed contained within a cylindrical container, including a blast furnace. [Background technology]

[0002] In recent years, there has been a growing movement to reduce emissions of CO2 gas (carbon dioxide), one of the greenhouse gases, making the reduction of coal-derived reducing agents in blast furnace operations an urgent necessity. Reducing agents play two roles: generating heat in the furnace to raise the temperature of the charges, and reducing iron-based raw materials (iron ore, sintered iron ore, iron ore pellets, etc.) in the furnace. Hydrogen is attracting attention as a reducing agent aimed at reducing CO2 gas emissions. Since the reduction rate by hydrogen is faster than that by CO gas, injecting hydrogen-based reducing gas into the blast furnace makes it possible to simultaneously reduce CO2 gas emissions and increase reduction efficiency.

[0003] Since the reduction of iron-based raw materials by hydrogen is an endothermic reaction, there was a problem that the heating of the charge material in the blast furnace was delayed, preventing smooth reduction. Furthermore, when high-temperature gas was blown in from the shaft section to prevent insufficient heating of the charge material, the particle packing bed of the charge material became fluidized, causing the descent of the charge material to become unstable. Therefore, operating methods have been disclosed to avoid the effects of insufficient heating of the charge material in the upper part of the furnace while preventing the fluidization of the packing particles constituting the packing bed. Patent Document 1 discloses an operating method for a blast furnace in which hot air with an oxygen enrichment rate of 20 volume% or less is blown into the blast furnace from a tuyer, and preheating gas is blown in from a preheating gas blowing section at a predetermined position. Patent Document 2 discloses an operating method for a blast furnace in which shaft gas is blown in from the shaft section of the blast furnace, and the flow velocity of the shaft gas is set to 100 m / s or less.

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

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

[0006] [Non-Patent Document 1] "Method for Measuring the Angle of Repose and Internal Friction Angle of Powders," Ryuichi Aoki, Journal of Powder Technology Research Society, Vol. 6, No. 1, 1969, pp. 3-8. [Non-Patent Document 2] Ryuichi Aoki, "On the Friction Angle of Powders and Granules," Chemical Engineering, Vol. 24, No. 8, 1960, pp. 598-600. [Non-Patent Document 3] Sato et al., Kawasaki Steel Technical Report, vol. 29 (1997), pp. 30-36. [Overview of the project] [Problems that the invention aims to solve]

[0007] However, Patent Documents 1 or 2 focus solely on the gas flow velocity of the shaft gas injection nozzle (hereinafter also referred to as the SGI nozzle) to suppress fluidization, and do not adequately consider the influence of other blast furnace conditions, such as the shape of the SGI nozzle or the properties of the packing particles constituting the packed bed. Therefore, even if the method of Patent Documents 1 or 2 is applied to a packed bed with conditions significantly different from those in Patent Documents 1 or 2 to control the gas flow velocity, it is expected that the packing particles will still fluidize, indicating room for improvement.

[0008] In view of the above issues, the present invention aims to provide a method for treating a packed bed that can suppress the fluidization of packed particles even when gas is supplied to the packed bed under various conditions from the side of the container. [Means for solving the problem]

[0009] As a result of intensive studies to solve the above problems, the present inventors have obtained the following findings. The vertical length D of the nozzle opening of a nozzle provided on the side portion of a cylindrical container , inj , ,

[0012] , h , the harmonic mean particle diameter D of all the packed particles constituting the packed bed P , at the height position of the nozzle, the horizontal impinging pressure P of the gas supplied from the nozzle inj , and the horizontal powder pressure P of the packed bed h . By satisfying a predetermined relationship among these four parameters, the fluidization of the packed particles can be suppressed. Further, P inj and P h can be calculated by a predetermined formula from the characteristic values of the packed particles and the characteristic values of the gas blown from the nozzle, etc.

[0010] That is, the gist configuration of the present invention is as follows.

[0011] [1] A method for treating a packed bed accommodated in a cylindrical container, comprising a step of supplying a first gas into the cylindrical container from a nozzle provided on a side portion of the cylindrical container with the packed bed accommodated in the cylindrical container, the step being performed under conditions satisfying the following formula (1). D T / D P ≦12×(P inj / P h ) -0.21 ···(1) Here,[[]] D T : The vertical length (m) of the nozzle opening of the nozzle D P : The harmonic mean particle diameter (m) of all the packed particles constituting the packed bed P inj : The horizontal impinging pressure (Pa) of the first gas at the height position of the nozzle P h : The horizontal powder pressure (Pa) of the packed bed at the height position of the nozzle .

[0012] [2] The impinging pressure P inj and the powder pressure P hHowever, the method for processing the packed bed described in [1] above is calculated based on the following equations (2) to (5).

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[0013] [3] A method for processing a packed bed according to [1] or [2] above, wherein a second gas is generated that rises inside the cylindrical container by supplying gas from a supply port provided at the bottom of the cylindrical container.

[0014] [4] The method for processing a packed bed according to any one of the above [1] to [3], wherein the cylindrical container is a blast furnace. [Effects of the Invention]

[0015] According to the method for processing a packed bed of the present invention, when supplying gas to the packed bed from the side of the container, it is possible to suppress the fluidization of the packed particles. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of a cylindrical container used in an embodiment of the present invention. [Figure 2] This is a schematic diagram of a blast furnace operation method in an embodiment of the present invention, where a cylindrical container is used as the blast furnace. [Figure 3] This figure shows a graph illustrating the relationship between DT / DP and Pinj / Ph in an embodiment of the present invention. [Figure 4] This figure shows the relationship between DT / DP and Pinj / Ph in the calculation results when the present invention is applied to a blast furnace. [Modes for carrying out the invention]

[0017] The following describes embodiments of the method for processing a packed bed contained in a cylindrical container according to the present invention. Note that the embodiments described below are examples that embody the present invention, and these specific examples do not limit the configuration of the present invention.

[0018] Generally, physical phenomena can be described not by specific physical quantities themselves (e.g., gas flow rate or nozzle diameter), but by using appropriately dimensionless parameters. This allows for the description of generalized phenomena applicable to a wide range of subjects, independent of the size of the equipment, its physical properties, and operating conditions (flow rate, temperature, pressure, etc.). This is known as the similarity principle and is a commonly used evaluation method when reproducing large-scale equipment such as blast furnaces, which are difficult to measure, using cold-scale models. Based on various experimental results using cylindrical containers, the inventors investigated whether the fluidization phenomenon of packed particles could be described using dimensionless parameters, independent of equipment scale, particle properties, gas properties, or operating conditions.

[0019] In this invention, the state in which the packing particles are fluidized is defined as follows: When gas is blown into a packed bed from a nozzle attached to a cylindrical container, the packing particles remain stationary under conditions of low gas flow rate, but as the gas flow rate is increased, the packing particles begin to move. In this invention, the depth of the cavity created in front of the nozzle opening of the nozzle inside the cylindrical container (hereinafter also referred to as the fluidization depth) is the harmonic mean particle size D of the packing particles, as described later. P A state in which the packing particles are fluidized is defined as a state in which the fluidization depth reaches three times or more the harmonic mean particle size D. P When the fluidization depth exceeds three times the harmonic mean particle size D, the exchange of packing particles located above and below becomes more rapid, increasing the likelihood of the packed bed structure collapsing. In packed beds where packing particles descend uniformly, such as in blast furnaces, the exchange of packing particles located above and below destabilizes the descent of the packing particles and negatively impacts operations. Therefore, the fluidization depth is the harmonic mean particle size D. P It is necessary to maintain a ratio of less than three times the above. Furthermore, while it is conceivable that the packing particles may be rotating, such as in the raceway in front of a blast furnace tuyer, when the packing particles are fluidized, the method is not limited to such cases.

[0020] As a result of diligent research, the inventors have newly discovered that the fluidization phenomenon of filling particles occurs when the horizontal impulse pressure of the first gas at the nozzle height significantly exceeds the horizontal powder pressure of the packed bed at the nozzle height. In addition to the above, they found that the fluidization behavior is also influenced by the flow velocity of the first gas blown in from the nozzle on the side of the container, as well as the vertical length of the nozzle opening of the nozzle into which the first gas is blown. Based on these findings, they investigated conditions applicable to a wide range of filling particles and discovered that it is possible to prevent the fluidization of filling particles by processing the packed bed under conditions that satisfy the following equation (1). D T / D P ≤12 × (P inj / P h ) -0.21 ...(1) Here, D T : The vertical length (m) of the nozzle opening of the aforementioned nozzle. D P : The harmonic mean particle size (m) of all packing particles constituting the packing bed. P inj : Horizontal impulse pressure (Pa) of the first gas at the nozzle height position. P h : Horizontal powder pressure (Pa) of the packed bed at the nozzle height position. That is the case.

[0021] Note that D in equation (1) above T / D P The lower limit is not particularly limited, but in order to prevent the pressure drop in the nozzle from becoming too high, D T / D P It is preferable that this value is 1 or greater.

[0022] In equation (1) above, P is negative for reasons such as the fact that g', which will be explained later, inj / P hIf the value is less than 0, the right-hand side of equation (1) will not be a real number, and it will not be possible to process the packed bed under the conditions that satisfy equation (1). In other words, in such cases, the provisions of the present invention are not met, and the case falls outside the scope of the present invention. Furthermore, in order to supply the first gas into the cylindrical container from the nozzle, in the present invention, P inj / P h The case where it becomes 0 is not expected. Therefore, P inj / P h It should be greater than 0, and preferably 0.1 or higher. On the other hand, P inj / P h There is no particular limit on the upper limit, but P inj / P h The number will generally be 1000 or less.

[0023] [Cylindrical container] The following describes the configuration of the cylindrical container that is a prerequisite for satisfying the above equation (1).

[0024] The cylindrical container used in one embodiment of the present invention contains a packed bed inside, has a supply port at the bottom, and has a nozzle on the side. Figure 1 shows a schematic diagram of the cylindrical container 100 used in an embodiment of the present invention. With the packed bed 10 contained inside the cylindrical container 100, a first gas 14 is supplied into the cylindrical container 100 from a nozzle 12 provided on the side of the cylindrical container 100. Alternatively, gas may be blown into the cylindrical container 100 from a supply port 16 provided at the bottom of the cylindrical container 100 to generate a second gas 18 that rises inside the cylindrical container. During processing, a vibrating feeder 20 installed at the bottom of the cylindrical container 100 extracts the packing particles constituting the packed bed 10 at a constant speed, causing the raw material particles to descend. At this time, the height of the packed bed 10 can be kept constant by periodically replenishing the packing particles 24 from the top of the cylindrical container 100.

[0025] The nozzle 12 is positioned lower than the maximum height of the packed bed 10 contained inside the cylindrical container 100, with the maximum height of the packed bed 10 being the reference height. Preferably, the value obtained by dividing the distance from the reference height to the installation height of the nozzle 12 by the distance from the reference height to the position of the supply port 16 is between 0.1 and 0.9. Setting this value to 0.1 or higher effectively suppresses the fluidization and blow-through of the packing particles on the surface of the packed bed 10. On the other hand, setting this value to 0.9 or lower effectively suppresses the introduction of the first gas 14 before the second gas 18 spreads to the furnace wall of the cylindrical container 100. Preferably, the cylindrical container 100 is installed so that its height axis is parallel to the vertical direction. The cross-sectional shape of the cylindrical container is not particularly limited, but for example, a cylindrical container with a cylindrical cross-section can be used.

[0026] A blast furnace is an example of a cylindrical container having such a structure. In one embodiment of the present invention, it is preferable that the cylindrical container used is a blast furnace. The conditions for applying the present invention to a blast furnace will be described later. In addition to blast furnaces, the present invention can also be applied when processing is carried out using a shaft furnace or the like, which has a structure that blows gas from the sides and bottom of the cylindrical container.

[0027] Figure 2 shows a schematic diagram of the operation method of a blast furnace in one embodiment of the present invention, where a cylindrical container is used as the blast furnace. The inside of the blast furnace 102 is filled with raw material particles 30, an SGI nozzle 32 is provided in the shaft section, and a tuyeres 34 for blowing in oxygen-containing gas and a blown reducing agent is provided at the bottom. In 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 Bosch gas 38 rising from the bottom of the blast furnace. In addition, molten iron 40 can be removed from the bottom of the blast furnace 102 during processing.

[0028] The packing particles that constitute the packed layer contained inside the cylindrical container can be appropriately selected by the implementer depending on the type and application of the cylindrical container. The packed layer may be composed of multiple types of packing particles.

[0029] When the cylindrical container is a blast furnace, the packed bed can consist of iron-based raw materials (iron ore, sintered iron ore, iron ore pellets, reduced iron, etc.) and reducing agents (coke, etc.). The particle size of the raw materials constituting the packed bed is appropriately selected according to the size of the cylindrical container; for example, in a blast furnace with a height of 10 m and an inner furnace diameter of 3 m, the average particle size can be between 10 mm and 50 mm. Also, when the cylindrical container is a blast furnace, the average bulk density of the packed bed is 500 kg / m³. 3 More than 1810kg / m 3 The following is preferable:

[0030] [First gas and second gas] Air or the like can be used as the first gas supplied to the cylindrical container from the nozzle described later and as the second gas rising inside the cylindrical container. From the viewpoint of preventing condensation from forming inside the packed bed, 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 protecting the device, the temperature of the first gas is preferably below the heat resistance temperature of the device, for example, 60°C or lower if the cylindrical container is made of PVC.

[0031] When the cylindrical container is a blast furnace, granular ore raw materials and coke are charged from the top of the blast furnace, and oxygen-containing gas and a blown reducing agent (such as methane gas) are blown in from a 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 raw materials (hereinafter also referred to as Bosch gas) becomes the second gas, and the high-temperature gas (hereinafter also referred to as SGI gas) blown in from a nozzle (SGI nozzle 32) located in the blast furnace shaft becomes the first gas.

[0032] From the viewpoint of not inhibiting 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 a temperature equivalent to that of the Bosch gas when it rises 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 temperature, the temperature of the SGI gas is preferably 1200°C or lower, and more preferably 1000°C or lower.

[0033] The blast gas supplied to the tuyere of a blast furnace is an oxygen-containing gas such as air or oxygen. From the viewpoint of reducing CO2 gas emissions, it is preferable that the blast gas be oxygen. Similarly, from the viewpoint of reducing CO2 gas emissions, it is preferable that the reducing agent blown in from the tuyere be a hydrogen-based reducing gas such as methane. The temperature of the gas supplied to the tuyere is preferably 0°C or higher from the viewpoint of ensuring the gas temperature at the tip of the tuyere. Furthermore, the temperature of the gas supplied to the tuyere is preferably 1300°C or lower from the viewpoint of preventing excessive temperature rise of the gas at the tip of the tuyere.

[0034] Bosch gas consists of reducing gas (CO, H2, N2, etc.) generated when the blast gas supplied to the tuyeres of the blast furnace and the blown reducing agent react with the coke at the tip of the tuyeres in the raceway. From the viewpoint of promoting the reduction reaction of the ore, it is preferable that the temperature of the Bosch gas at nozzle height be 560°C or higher. Furthermore, from the viewpoint of preventing softened and molten ore from adhering to the nozzle, it is preferable that the temperature of the Bosch gas at nozzle height be 1200°C or lower.

[0035] [nozzle] Next, the nozzles provided on the side of the cylindrical container will be described. If there is one or more nozzles provided on the side of the cylindrical container, the amount of first gas injected can be suitably maintained while suitably suppressing the fluidization of the filling particles. On the other hand, if the number of nozzles is 100 or less, equipment costs and maintenance costs can be suitably kept down, and operation can be carried out efficiently. Therefore, it is preferable that the number of nozzles be 100 or less, and more preferably 50 or less. When multiple nozzles are installed, it is preferable that nozzles installed at the same height on the side of the cylindrical container be provided at equal intervals in the circumferential direction of the cylindrical container. The same applies when the nozzles are installed in multiple stages in the height direction, as will be described later.

[0036] Furthermore, the nozzle does not necessarily have to be positioned horizontally; it may be positioned diagonally to the side of the cylindrical container. When the nozzle is positioned diagonally to the side of the cylindrical container, the nozzle height position shall be the height of the nozzle tip.

[0037] Furthermore, when multiple nozzles are installed, all nozzles may be installed at the same height, but it is not necessary for all nozzles to be at the same height, and the nozzles may be arranged in multiple stages. For example, the nozzles may be arranged in a staggered pattern of two or more stages. When the nozzles are arranged in multiple stages, the present invention is applied to each nozzle. Then, if the present invention is satisfied at all nozzles, it is determined that there is no fluidization.

[0038] The cross-sectional shape of the nozzle opening perpendicular to the gas injection direction (i.e., the nozzle opening shape) is not limited to a circle, but may be rectangular, for example, and regardless of the shape, the maximum length in the vertical direction of the nozzle opening is D. TThe nozzle opening is rectangular. An example of a nozzle with a slit-shaped tip is one in which there may be multiple slits. Furthermore, the nozzle is not limited to a single-hole nozzle, and a multi-hole nozzle may be used. As a multi-hole nozzle, one can be used that has multiple adjacent discharge holes arranged at equal intervals. For example, a nozzle formed by bundling multiple pipes, a nozzle tip with a multi-hole shape attached to the end of a single pipe, or a nozzle with a mesh installed on a single-hole nozzle to form a multi-hole can be used. Also, when using a multi-hole nozzle, the vertical length D of the nozzle opening T This length is defined as the vertical distance from the lowest nozzle to the highest nozzle among the multiple discharge holes of the porous nozzle. When using a porous nozzle, the effect of preventing the entry of filling particles into the nozzle can be obtained. If multiple nozzles are installed, the cross-sectional shape of each nozzle may differ, but it is preferable that all nozzles have the same cross-sectional shape. If the cross-sectional shapes of the nozzles differ, the present invention is applied to each nozzle separately. If the present invention is satisfied in all nozzles, it is determined that there is no fluidization.

[0039] [D T ] The vertical length D of the nozzle opening. T is D P With the above conditions, the first gas is diffused appropriately while keeping the pressure drop in the nozzle low. Therefore, D T is D P It is preferable that it be 1 or more times. For example, D P If it is 0.02m, then D T It is preferable that it is 0.02 m or more. On the other hand, D T is D P If it is 10 times or less, backflow of packing particles in the packed bed into the nozzle can be effectively prevented. Therefore, D T D P Preferably, it is 10 times or less, D P It is more preferable that it be 5 times or less. For example, the harmonic mean particle size D of all filling particles. P If it is 0.02m, then D TIt is preferably 0.20 m or less, more preferably 0.10 m or less.

[0040] In addition, the above formula (1) is preferably used when determining D during the design of the cylindrical container. However, when it is difficult to adjust D, T the operating conditions may be determined by adjusting D, T P, P P, inj and P. h

[0041] [D P When the harmonic mean particle size D of all the packed particles constituting the packed bed is 0.001 m or more, the air permeability resistance of the packed bed can be kept low, and the gas can be stably circulated without causing fluidization or blowing through of the packed particles. Therefore, D P is preferably 0.001 m or more. On the other hand, when D P is 0.050 m or less, heat transfer and reaction between the gas and the packed particles can proceed without delay. Therefore, D P is preferably 0.050 m or less.

[0042] The harmonic mean particle size D of all the packed particles constituting the packed bed P can be obtained as follows. First, 1 kg of a powder sample of the particles to be packed in the cylindrical container is collected and dried. Then, the powder sample is sieved in descending order of mesh size using sieves with mesh sizes of 0.25, 0.5, 1, 2, 4, 8, 16, 31.5, 63, and 125 mm, and the weight ratio of each particle size is measured. From the measurement results, the harmonic mean particle size D P is obtained by the following formula (6).

Equation

[0043] <000045​​​In the above measurement, the representative particle diameter x of each particle size range i shall be the geometric mean of the larger screen opening and the smaller screen opening. Also, generally, in order to suppress the fluidization of the packed particles, fine powder with a particle diameter of 0.25 mm or less is sufficiently removed in advance from the packed particles used in the packed bed. Therefore, the amount of fine particles with a particle diameter of 0.25 mm or less contained in the packed particles is very small and can be ignored. For particles with a particle diameter of 125 mm or more, the geometric mean of 125 mm and the maximum particle diameter among the collected particles shall be used as the representative particle diameter. When the packed bed is composed of multiple particle species, the harmonic mean diameter of each particle species is measured, and a weighted average value is obtained based on the mixing ratio (bulk volume ratio) of each particle species in the packed bed. The obtained average value is D p and shall be used as such.

[0044] [P inj The horizontal impact pressure P of the first gas at the height position of the nozzle inj is 0.1 kPa or more, an effect of suppressing the intrusion of particles into the nozzle can be obtained. Therefore, P inj is preferably 0.1 kPa or more. On the other hand, when P inj is 40000 kPa or less, the pressure loss of the nozzle can be suppressed to a low level. Therefore, P inj is preferably 40000 kPa or less. Since it is difficult to directly obtain P inj , it is preferable to use Equation (2).

[0045] [P h The horizontal powder pressure P of the packed bed at the height position of the nozzle h is 0.1 kPa or more, sudden blow-through due to fluctuations in the gas flow velocity in the packed bed, etc. can be suppressed. Therefore, P h is preferably 0.1 kPa or more. On the other hand, when P h is 50 kPa or less, pulverization of the particles constituting the packed bed can be suppressed. Therefore, P h is preferably 50 kPa or less. Since it is difficult to directly obtain P h ​​Equation (3) may also be used, and a load cell is installed on the inner wall of the cylindrical container to directly P h It can also measure this.

[0046] The inventors of the present invention conducted a further detailed investigation and found that P h and P inj We have made it possible to estimate this with even greater precision and have established a method that can predict with high accuracy whether or not fluidization of the packing particles will occur. Specifically, P inj and P h These can be expressed by the following equations (2) and (3).

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[0047] The definitions and methods for determining the various coefficients used in equations (2) and (3) are explained below.

[0048] [A BF ] The area of ​​the horizontal cross-section of the cylindrical container at a height midway between the nozzle and the top surface of the packed bed is A. BF (m 2 ) Note that if the nozzles are installed in multiple stages in the height direction, A will be applied to each nozzle. BF (m 2 ) is obtained. In this case, the present invention is applied to each nozzle, and if the present invention is satisfied in all nozzles, it is determined that there is no fluidization. The same applies below.

[0049] [P BF ] P is the circumference of the cylindrical container in the horizontal cross-section at a height position midway between the nozzle and the top surface of the packed bed. BF (m) Note that if the nozzles are installed in multiple stages in the height direction, P BF Get (m).

[0050] [h] Let h(m) be the distance from the nozzle's height position to the top surface of the packed bed. If the top surface of the packed bed is not horizontal, use the height of the top surface of the packed bed on the wall above the nozzle. If the nozzles are installed in multiple stages in the height direction, obtain h(m) for each nozzle.

[0051] [ρ p ] The average bulk density of all packing particles constituting the packed bed is ρ p (kg / m 3 ) Let ρ p This can be determined as follows: Fill a container with the filling particles in a size sufficiently larger than the average particle size of the filling particles (for example, the inner diameter and height are each about 20 times the harmonic mean particle size of the filling particles). Measure the weight of the filling particles and divide the weight of the filling particles by the internal volume of the container to obtain the value ρ. p If the packed bed is composed of multiple particle types, the bulk density of each particle type is measured as described above, and a weighted average value is calculated based on the mixing ratio (bulk volume ratio) of each particle type in the packed bed, and the obtained average value is ρ p Let's assume that.

[0052] [ε] Let ε(-) be the average porosity of the packed bed. ε can be determined as follows: First, measure the apparent density ρ of the packed particles using a liquid weighing method or the like. If the packed bed is composed of multiple particle types, measure the apparent density of each particle type and calculate a weighted average value based on the mixing ratio of each particle type in the packed bed (apparent volume ratio, apparent volume ratio of each particle type = weight of each particle type in the packed bed / apparent density of each particle type). The resulting average value is taken as ρ. Next, the obtained ρ and the above ρ p Therefore, we find ε using the following equation (7). ε = 1 - ρ p / ρ ···(7)

[0053] [ φ i ] The average internal friction angle of all filling particles constituting the packed bed is φ i Let's use (°). iThis can be measured using the shear testing apparatus described in Non-Patent Document 1. If the packed bed is composed of multiple particle types, the internal friction angle of each particle type is measured, and a weighted average value is calculated based on the mixing ratio (bulk volume ratio) of each particle type in the packed bed. The resulting average value is then calculated as φ i Let's assume that.

[0054] [k] Let k be the average active powder pressure coefficient of all filling particles constituting the packed bed. k is equal to the above φ i This can be calculated using the following equation (4).

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[0055] [x] Let x (m) be the upper limit of the penetration distance of the first gas. x represents the state in which the packing particles are fluidized, i.e., the harmonic mean particle size D. P The value should be three times that value. The state in which the filling particles become fluid is as described above.

[0056] [c w ] The average wall friction coefficient of all filling particles constituting the packed bed is c w (-) w This can be determined as follows: The wall friction angle φ is obtained using the method described in Non-Patent Literature 2. w The coefficient of friction c of the wall surface is calculated using the following equation (8). w The following is calculated: If the packed bed is composed of multiple particle types, the wall friction coefficient of each particle type is determined, and a weighted average value is calculated based on the mixing ratio (bulk volume ratio) of each particle type in the packed bed, and the resulting average value is calculated as c w Let's assume that. c w =tan(φ w ) ···(8)

[0057] [u h ] The horizontal gas flow velocity of the nozzle is u h Let's assume (m / s). hThis can be determined as follows: The gas flow rate V of the first gas injected into each nozzle. 1N (Nm 3 The temperature-pressure corrected flow rate V1 is calculated by correcting the flow rate ( / h) with the injection temperature and pressure of the first gas, and the temperature-pressure corrected flow rate V1 is divided by the cross-sectional area of ​​the nozzle opening. h Calculate the temperature-pressure corrected flow rate V1(m 3 Specifically, the value of / h) can be calculated using the following equation (9), where P1 (PaG) is the gauge pressure of the first gas at the nozzle position and T1 (°C) is the gas temperature. V1=V 1N ×{(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 for the above correction, it is preferable to directly measure them by installing a pressure gauge and thermometer at the nozzle location. If direct measurement is difficult, a pressure gauge and thermometer may be installed in the piping upstream of the nozzle, or the value of the blast furnace wall pressure gauge near the nozzle may be used instead of the nozzle pressure value. Alternatively, the pressure and temperature at the nozzle location may be calculated and used by numerical simulation. Note that the horizontal gas flow velocity may differ for each nozzle, for example, when nozzles with different cross-sectional shapes are used in combination. If the horizontal gas flow velocity differs for each nozzle, the flow rate of each nozzle should be measured and the flow rate of each nozzle should be obtained. In this case, the hot pressure corrected flow rate of each nozzle should be divided by the cross-sectional area of ​​each nozzle. h The coefficient of the first gas can be calculated, and the presence or absence of fluidization can be individually evaluated using equation (1). Note that if the nozzle is not installed horizontally, 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 u h Let's assume that.

[0059] [u v ] The vertical upward gas flow velocity inside the cylindrical container at the nozzle height position is u v Let's assume (m / s). v This can be determined as follows: The total flow rate V of the first and second gases blown into the container. 2N (Nm3 The temperature- and pressure-corrected flow rate V2(m) is calculated by correcting the average gas temperature and average pressure inside the cylindrical container from the nozzle height position to the top surface of the packed bed (m / h). 3 Calculate the ( / h). Divide the temperature-pressure corrected flow rate V2 by the cross-sectional area of ​​the cylindrical container at a height position midway between the nozzle and the top surface of the packed bed, u v Calculate the (m / s) temperature-pressure corrected flow rate V2(m 3 Specifically, the u ( / s) can be calculated using the following formula (10) with respect to the average gauge pressure P2 (PaG) and average gas temperature T2 (°C) between the height position of the nozzle and the height position of the top of the packed bed. Note that if the nozzles are installed in multiple stages in the height direction, the u v Calculate (m / s). V2=V 2N ×{(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 above correction, a thermometer and a pressure gauge can be installed inside the cylindrical container at a height midway between the nozzle and the top surface of the packed bed, and the 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 it is difficult to install the instruments, they may be installed near the wall. Alternatively, the pressure and temperature at that location inside the cylindrical container may be calculated and used through numerical simulation.

[0061] [ρ sgi ] The density of the first gas is ρ sgi (kg / m 3 ) Let ρ sgi This can be calculated using the ideal gas law from the composition, temperature, and pressure of the first gas.

[0062] [μ sgi ] The viscosity of the first gas is μ sgi Let (Pa·s). Viscosity values ​​for pure gas species can be obtained from various sources (e.g., the Science Almanac). μ sgiTo calculate this, first obtain the viscosity values ​​of each pure gas species at the temperature of the first gas. Then, calculate the viscosity by weighting the viscosity values ​​of each pure gas species according to the mixing ratio (volume ratio) based on the composition of the first gas.

[0063] [ρ bf ] The average gas density inside the cylindrical container is ρ bf (kg / m 3 ) Let ρ bf This can be calculated using the ideal gas law from the mixed gas composition, temperature, and pressure of the first and second gases at the nozzle height. Note that if only the first gas is injected, the flow rate of the second gas is set to zero for the calculation.

[0064] [μ bf ] The average gas viscosity inside a cylindrical container is μ bf Let (Pa·s). bf This is the viscosity μ of the first gas. sgi Similarly, the viscosity values ​​of the pure gas species at the second gas temperature can be obtained and calculated by weighting and averaging them according to the mixing ratio (volume ratio) based on the composition of the second gas.

[0065] Furthermore, if the packed bed treatment involves a reaction, the composition and number of moles of the gas inside the cylindrical container change during the treatment. Therefore, it is preferable to calculate the various characteristic values ​​of the gas inside the cylindrical container, taking into account the changes in gas composition and number of moles during treatment, using reaction calculations, etc., to perform more precise calculations. For example, if the cylindrical container is a blast furnace, the vented gas (air, oxygen, etc.) blown in from the tuyere, the reducing agent (methane gas, pulverized coal, etc.) blown in from the tuyere, and the coke present in the furnace react near the tuyere to produce Bosch gas mainly composed of carbon monoxide and hydrogen. This Bosch gas rises inside the blast furnace and affects the fluidization behavior near the shaft nozzle. Therefore, if the cylindrical container is a blast furnace, it is preferable to use the Bosch gas after the reaction near the tuyere as the second gas.

[0066] [f] Let f(-) be the average shape factor of all packing particles constituting the packed bed. f can be determined as follows: Prepare a container that can introduce gas at a uniform flow rate and fill the container with the packing particles to be measured. The cross-sectional area of ​​the container should be sufficiently larger than the average particle size of the packing particles (for example, about 20 times the average particle size). While the gas flows through the container, measure the pressure at two observation points along the direction of gas flow. From the differential pressure ΔP and the distance L between the observation points obtained from the measurement results, calculate the shape factor using the following equation (11) (the so-called Elgin equation). Note that ε and μ in equation (11) are... bf , μ v , D p , and ρ bf The method for determining this is as described above, using the values ​​for the packed particles to be measured and the gas used for the measurement. If the packed bed is composed of multiple particle types, the shape factor is determined for each particle type as described above, and a weighted average value is calculated based on the mixing ratio (bulk volume ratio) of each particle type in the packed bed. The resulting average value is denoted as f.

number

[0067] [g] Gravitational acceleration is g(m / s²). 2 )

[0068] [g'] The inventors conducted numerous experiments by varying the gas and particle conditions and discovered that, even under the same nozzle shape and nozzle gas flow velocity conditions, fluidization near the nozzle is more likely to occur when the gas flow velocity rising within the cylindrical container is higher. Further detailed investigations led to the following findings: The gas rising within the cylindrical container has the effect of reducing the gravitational acceleration acting on the packed particles, thereby reducing powder pressure. Therefore, the vertical upward gas flow velocity within the cylindrical container u v By using the apparent gravitational acceleration g', which takes into account the effects of gravity, it is possible to accurately predict whether or not fluidization will occur, even when gas is rising inside a cylindrical container.

[0069] g' can be determined using the above-mentioned values ​​from the following equation (5). Note that in equation (5), if the gas flow velocity in the vertical upward direction is extremely large, g' may be a negative value. In such cases, the right-hand side of equation (1) will not be a real number, and therefore it will not be possible to process the packed bed under the conditions that satisfy equation (1), which falls outside the scope of the present invention.

number

[0070] Furthermore, if the cylindrical container is a blast furnace, a heat flow ratio of 1.1 or less can suppress insufficient heating of the raw materials inside the blast furnace. Therefore, a heat flow ratio of 1.1 or less is preferable, 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 failure of the furnace top equipment can be effectively suppressed. Therefore, a heat flow ratio of 0.4 or more is preferable, and more preferably 0.6 or more. The heat flow ratio (Ws / Wg) is a value calculated by the following formula (12).

number

[0071] For processes and conditions not described in this specification, conventional methods may be used. [Examples]

[0072] <Example 1: Experiment using a cold model apparatus> Using a cold model apparatus as a cylindrical container, a second gas was generated that rose inside the cylindrical container by supplying gas from the bottom of the container, while the first gas was supplied from a nozzle on the side of the cylindrical container to investigate the conditions under which the packed particles would fluidize.

[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 configuration is as described above. The cylindrical container 100 is a shape cut out symmetrically in the circumferential direction by 20° from a cylindrical container with an internal furnace port radius of 281 mm and a furnace height of 1570 mm. That is, the A of the cylindrical container used BF is 0.01378m 2 , P BF The length was 0.6601 m. In addition, the cylindrical container 100 was made of transparent PVC so that the fluidization behavior of the packed particles could be observed.

[0074] As shown in Figure 1, nozzles 12 were installed on the side (circumferential side) of the cylindrical container 100. The nozzle opening of the nozzle 12 was semicircular, and two nozzles were installed horizontally (0°) at a height of 605 mm from the supply port 16 located at the bottom of the cylindrical container. A camera (not shown) was installed on the side of the cylindrical container 100 to observe the fluidization of the packed particles in front of the nozzles 12. The semicircular radius of the nozzle opening cross-section (vertical length D of the nozzle opening) T The following tests were conducted by changing the value (equivalent to) within the range of 7.4 to 14 mm.

[0075] Both the first and second gases were air at room temperature (25°C) and atmospheric pressure (101325 Pa). That is, air was supplied to both nozzle 12 and supply port 16. Therefore, the density ρ of the first gas sgi and the average gas density ρ inside the cylindrical container bf The values ​​are the same. Similarly, the viscosity μ of the first gas sgi and the average gas viscosity μ inside the cylindrical container bf The values ​​are the same. The flow rate of the second gas was varied within the range of 0 to 371 NL / min, and the flow rate of the first gas was varied within the range of 8.7 to 1559.9 NL / min. The height of the top surface of the packed bed was varied within the range of 200 to 610 mm above the height of the nozzle.

[0076] The particles used to fill the cylindrical container are colored sand (harmonic mean diameter 1.7 mm, bulk density 1501 kg / m³). 3 ), sintered ore 1 (harmonic mean diameter 1.7 mm, bulk density 2198 kg / m³) 3 ), Sintered ore 2 (harmonic mean diameter 3.4 mm, bulk density 2229 kg / m³) 3 ), polyparticles (harmonic mean diameter 3.44 mm, bulk density 628 kg / m³) 3 We prepared four types.

[0077] To simulate the loading of raw material particles in a blast furnace, a vibrating feeder at the bottom of a cylindrical container was used to extract the packed particles at a constant speed, while simultaneously replenishing them from the top of the cylindrical container. By adjusting the amount of extracted and replenished packed particles, the height of the top surface of the packed bed was kept constant.

[0078] Table 1 shows the experimental conditions and results for each example. During the experiment, the fluidization depth was measured using a measuring tape installed in the apparatus. In cases where cavities of three times or more the harmonic mean diameter of the packing particles were confirmed, it was determined that the packing particles had fluidized, and "Yes" was indicated in the "Presence or Absence of Fluidization" column of Table 1. On the other hand, in cases where fluidization of the packing particles was not confirmed, "No" was indicated in the "Presence or Absence of Fluidization" column of Table 1.

[0079] Figure 3 shows the observation of whether or not fluidization of the filling particles occurs, D T / D P and P inj / P h The relationship between the two is plotted as follows. In Figure 3, "×" is plotted when fluidization occurs, and "○" is plotted when it does not occur in each example. Note that the line in Figure 3 represents the case where equation (1) is equal. Packed bed particle properties (harmonic mean particle size D p , average bulk density ρ p , average porosity ε, average shape factor f, average internal friction angle φ i , average wall friction coefficient c wEven when the vertical length of the nozzle opening, the first gas flow rate, the second gas flow rate, and the height of the top surface of the packed bed were changed, it was confirmed that fluidization did not occur under conditions that satisfied equation (1) of the present invention (the region to the lower left of the line shown in Figure 3), and fluidization occurred under conditions that did not satisfy equation (1) (the region to the upper right of the line shown in Figure 3). Note that No. 68 (Comparative Example) in Table 1 is not plotted in Figure 3 because the right-hand side of equation (1) is not a real number, but it was confirmed that fluidization occurred in this case as well. Therefore, it was confirmed that the present invention can be applied regardless of the scale of the equipment, particle properties, gas properties, and operating conditions.

[0080] [Table 1] TIFF0007861927000013.tif233131TIFF0007861927000014.tif233135TIFF00078619270 00015.tif233131TIFF0007861927000016.tif233136TIFF0007861927000017.tif233131

[0081] <Example 2: Application to large blast furnaces> Example 2 evaluates the application of the present invention to a large blast furnace. The blast furnace to which it was applied was 4300 m³. 3 The following scenario was assumed: The SGI nozzles installed in the blast furnace were assumed to have a circular cross-section, all positioned at the same height (single stage), and arranged at equal intervals around the circumferential direction of the blast furnace.

[0082] The total flow rate of SGI gas injected from n SGI nozzles was defined as the first gas flow rate. The flow rate of Bosch gas produced by the reaction of blown gas (oxygen) and reducing agent (methane, coke) near the tuyeres located at the bottom of the blast furnace was defined as the second gas flow rate. Gas density ρ of the upward gas flow. bf gas viscosity μ bf The gas density ρ was calculated using the gas composition, furnace temperature, and furnace pressure calculated using the blast furnace numerical simulation model described in Non-Patent Document 3. bf gas viscosity μ bfWhen calculating, the average value (shaft average) of the region (shaft) between the SGI nozzle height and the top surface of the raw material filling was used. bf , P bf Upward gas flow velocity u v This was calculated based on the furnace radius at an intermediate height between the SGI nozzle height and the furnace top height. The gas density ρ of the SGI gas injected from the SGI nozzle. sgi gas viscosity μ sgi The calculation was performed using the pressure at the SGI nozzle height, the gas composition injected from the SGI nozzle, and the gas temperature.

[0083] Three types of packing particles were considered: lumps of coke, small lumps of coke, and ore raw materials (sintered ore). The physical properties of the packing particles (harmonic mean particle size D) were also considered. p , average bulk density ρ p , average porosity ε, average shape factor f, average internal friction angle φ i , average wall friction coefficient c w The particle properties of each individual raw material particle (lump coke, small lump coke, ore raw material) were weighted and averaged according to the volume ratio of the raw material input amount to calculate the particle properties of each individual particle.

[0084] Table 2 shows the calculation results when applied to a blast furnace. Based on the obtained results, examples that satisfy formula (1) of the present invention are indicated as "None" in the fluidization determination result column of Table 2, and examples that do not satisfy are indicated as "Yes". Similarly in Figure 4, if formula (1) of the present invention is satisfied, it is determined that fluidization does not occur and plotted as "○", and if it is not satisfied, it is determined that fluidization occurs and plotted as "×". Note that the line in Figure 4 represents the case where formula (1) is equal.

[0085] [Table 2] TIFF0007861927000019.tif233131 [Industrial applicability]

[0086] According to the present invention, a method for treating a packed bed can be provided that can suppress the fluidization of packed particles even when gas is supplied to the packed bed under various conditions from the side of the container. [Explanation of symbols]

[0087] 100 cylindrical containers 102 Blast Furnace 10 Packed bed 12 nozzles 14. First Gas 16 supply ports 18. Second Gas 20 Vibration Feeder 22 Extraction of packing particles 24. Replenishing the filling particles 30 Raw material particles 32 SGI nozzles 34 Tuyere 36 SGI Gas 38 Bosch Gas 40 molten iron

Claims

1. A method for processing a packed bed contained in a cylindrical container, The cylindrical container is a blast furnace, and the packed bed is composed of packing particles to be filled into the blast furnace. A method characterized in that, with the packed layer contained within the cylindrical container, the step of supplying a first gas into the cylindrical container from a nozzle provided on the side of the cylindrical container is performed under conditions that satisfy the following formula (1). D Ｔ / D Ｐ ≦12×(P ｉｎｊ / P ｈ ) －０．２１ ・・・(1) Here, D Ｔ : The vertical length (m) of the nozzle opening of the aforementioned nozzle. D Ｐ : The harmonic mean particle size (m) of all packing particles constituting the packing layer. P ｉｎｊ : The horizontal impulse pressure (Pa) of the first gas at the height position of the nozzle. P ｈ : The powder pressure (Pa) in the horizontal direction of the packed bed at the height position of the nozzle That is the case.

2. The blast pressure P ｉｎｊ and the powder pressure P ｈ The method for processing a packed bed according to claim 1, wherein the calculation is performed based on the following formulas (2) to (5). [Math 1] [Math 2] [Math 3] [Math 4] Here, A ＢＦ : The area of ​​the horizontal cross-section of the cylindrical container at a height position midway between the nozzle and the upper surface of the filling layer (m²) ２ ) P ＢＦ : 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 packed layer. h: Distance (m) from the height position of the nozzle to the height position of the top surface of the packed bed. ρ ｐ : The average bulk density of all the packed particles (kg / m³) ３ ) ε: Average porosity of the packed bed (-) φ ｉ : The average internal friction angle (°) of all the filling particles k: Average active powder pressure coefficient of all filling particles (-) x: Infiltration distance of the first gas (m) c ｗ : Wall friction coefficient of the total filling particles (-) u ｈ : Horizontal gas flow velocity of the nozzle (m / s) u ｖ : The vertical upward gas flow velocity (m / s) inside the cylindrical container at the height position of the nozzle. ρ ｓｇｉ : Density of the first gas (kg / m³) ３ ) μ ｓｇｉ : Viscosity of the first gas (Pa·s) ρ ｂｆ : Average gas density (kg / m³) inside the cylindrical container ３ ) μ ｂｆ : The average gas viscosity (Pa·s) inside the cylindrical container. f: Average shape coefficient of all filling particles (-) g: acceleration due to gravity (m / s²) ２ ) g': Apparent gravitational acceleration (m / s²) inside the cylindrical container ２ ) That is the case.

3. A method for processing a packed bed according to claim 1 or 2, wherein a second gas that rises inside the cylindrical container is generated by supplying gas from a supply port provided at the bottom of the cylindrical container.

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