Apparatus and method for charging high-temperature granular material into heat recovery vessel, and method for recovering heat from high-temperature granular material

Abstract

To provide an apparatus for charging a high-temperature granular material including steel slag into a heat recovery vessel, capable of suppressing segregation of the high-temperature granular material inside the heat recovery vessel, thereby suppressing gas bias flow inside the heat recovery vessel and achieving high-efficiency heat recovery and carbonation.SOLUTION: An apparatus 100 for charging a high-temperature granular material Sg into a heat recovery vessel 10 includes: a feeder 20 that supplies the high-temperature granular material Sg; an intermediate vessel 30 having a bottom part 32 that can be opened and closed and a tubular shape having an open top part 34; a rotating mechanism 40 that rotates the intermediate vessel 30 about its center line X; and a conveying mechanism 50 that conveys the intermediate vessel 30. With the bottom part 32 of the intermediate vessel 30 closed, the high-temperature granular material Sg supplied from the feeder 20 is charged into the intermediate vessel 30 while the intermediate vessel 30 is rotated by the rotating mechanism 40. Thereafter, the intermediate vessel 30 is conveyed by the conveying mechanism 50 and positioned above the heat recovery vessel 10. Subsequently, the bottom part 32 of the intermediate vessel 30 is opened, and the high-temperature granular material Sg is dropped and charged into the heat recovery vessel 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for charging high-temperature granular materials including steel slag into a heat recovery vessel in which the high-temperature granular materials are accommodated and a gas is passed through the vessel to recover heat from the high-temperature granular materials using the gas. [Background technology]

[0002] Steelmaking processes, including the blast furnace method, produce steel slag as a by-product. Steel slag is made by separating and recovering impurities, such as alkaline earth metals, contained in iron ore or scrap, which are raw materials for steelmaking, during the iron refining process. The recovered molten slag is at a high temperature of over 1200°C and contains approximately 1.8 GJ / t-slag of heat. Therefore, recovering and utilizing this heat is expected to reduce CO2 emissions through energy savings. Furthermore, CO2 fixation technology, which reacts alkaline earth metals in steel slag with CO2 gas to form carbon dioxide, is also expected.

[0003] One known method for recovering the heat contained in steel slag is to charge the high-temperature solidified slag, which has been produced immediately after solidifying molten slag, into a heat recovery tank (heat recovery vessel) to form a packed bed, then inject room-temperature gas into the packed bed inside the vessel, which removes the heat from the solidified slag inside the vessel, releasing the high-temperature gas from the vessel and recovering it (the packed vessel method).If gas containing CO2 is injected during this process, the free lime (free-CaO) contained in the steel slag (solidified slag) can be carbonated at the same time.

[0004] Patent Document 1 describes "a heat recovery device for recovering heat by blowing a heat recovery gas into a heat recovery tank capable of accommodating a packed bed of high-temperature solidified material, the device comprising a lower air outlet for supplying the heat recovery gas into the heat recovery tank from the bottom of the heat recovery tank and a refrigerant supply port for supplying a refrigerant into the heat recovery tank from the inner wall of the heat recovery tank," and "a method for recovering heat from a high-temperature solidified material, the method comprising charging the high-temperature solidified material into the heat recovery tank and recovering heat from the high-temperature solidified material using the heat recovery gas and the refrigerant." Patent Document 1 aims to achieve efficient heat recovery by blowing the heat recovery gas into the heat recovery tank from the lower air outlet and supplying a refrigerant such as gas or water into the heat recovery tank from a refrigerant supply port provided on the inner wall of the heat recovery tank. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-184122 Summary of the Invention [Problem to be solved by the invention]

[0006] Steel slag (solidified slag) is obtained by crushing molten slag after solidifying it, and therefore has a wide particle size distribution, ranging from fine particles on the order of micrometers to coarse particles over 50 mm. Therefore, when steel slag is charged into a heat recovery vessel, segregation of the steel slag is likely to occur. When segregation of steel slag occurs, the gas flow path and flow rate within the heat recovery vessel become uneven, resulting in uneven gas flow. When uneven gas flow occurs, the heat recovery and CO2 fixation rates within the heat recovery vessel vary, resulting in reduced efficiency.

[0007] Gas flow-through occurs particularly in areas with a high concentration of coarse particles and around the inner walls of the heat recovery vessel. When this type of gas flow unevenness occurs within the heat recovery vessel, the cooling rate varies depending on the location within the vessel in the temperature range where radiant heat is ineffective during the heat recovery process, which can result in the recovered gas temperature becoming unintentionally high. Furthermore, when gas flow unevenness occurs during the carbonation process, the slag temperature decreases in areas where gas flow-through occurs, and becomes high in areas where gas flow is difficult. During the carbonation reaction, the reaction rate is high in areas with high slag temperatures and low in areas with low slag temperatures, resulting in variations in the amount of carbonation. This can lead to uneven carbonation and heat recovery rates.

[0008] However, Patent Document 1 does not describe any specific method for charging high-temperature granular materials containing steel slag into a heat recovery vessel, and is unable to suppress segregation of steel slag in the heat treatment vessel.

[0009] In view of the above problems, the present invention aims to provide an apparatus and method for charging high-temperature granular material into a heat recovery vessel, which can suppress the segregation of high-temperature granular material, including steel slag, within the heat recovery vessel, thereby suppressing the uneven flow of gas within the heat recovery vessel and achieving highly efficient heat recovery and carbonation. [Means for solving the problem]

[0010] In order to solve the above problems, the inventors conducted extensive research and found that segregation of steel slag in a heat treatment vessel occurs due to the method of charging the steel slag into the heat treatment vessel, and discovered that by adopting a specific charging method, the steel slag can be charged uniformly into the heat treatment vessel.

[0011] The gist and configuration of the present invention are as follows. [1] An apparatus for charging high-temperature granular materials containing steel slag into a heat recovery container in which gas is passed through the container to recover heat from the high-temperature granular materials using the gas, a feeder for supplying the hot granular material; a cylindrical intermediate container having an openable bottom and an open top; a rotation mechanism that rotates the intermediate container about its center line; a conveying mechanism for conveying the intermediate container; and With the bottom of the intermediate container closed, the intermediate container located below the feeder can be rotated by the rotation mechanism, and the high-temperature granular material supplied from the feeder can be charged into the intermediate container from the top, The intermediate container containing the high-temperature granular material can be transported by the transport mechanism and placed above the heat recovery container having an open top, The bottom of the intermediate container can be opened to allow the high-temperature granules to fall, and the high-temperature granules can be charged into the heat recovery container from the top. A device for charging high-temperature granular material into a heat recovery vessel.

[0012] [2] The device for charging high-temperature granular material into a heat recovery vessel according to [1] above, wherein the feeder is a vibrating feeder.

[0013] [3] The device for charging high-temperature granular material into a heat recovery vessel according to [1] or [2] above, wherein a charging bell is disposed at the top of the heat recovery vessel.

[0014] [4] An apparatus for feeding high-temperature granular material into a heat recovery container according to any one of [1] to [3] above, wherein the feeder is controlled so that the time required for feeding 1 kg of the high-temperature granular material from the feeder is 1 second or more and 60 seconds or less.

[0015] [5] An apparatus for loading high-temperature granular material into a heat recovery container described in any one of [1] to [4] above, wherein the rotation mechanism is controlled so that the number of rotations of the intermediate container per 1 kg of high-temperature granular material supplied from the feeder is 0.1 rotations or more and 8 rotations or less.

[0016] [6] A method for charging high-temperature granular materials containing steel slag into a heat recovery vessel in which a gas is passed through the vessel and heat is recovered from the high-temperature granular materials by the gas, the method comprising: a first step of feeding the hot granular material with a feeder; a second step of preparing a cylindrical intermediate container having an openable bottom and an open top, disposing the intermediate container below the feeder with the bottom of the intermediate container closed, and rotating the intermediate container about its center line as an axis to charge the high-temperature granular material supplied from the feeder into the intermediate container from the top; a third step of transporting the intermediate container containing the high-temperature granular material and placing it above the heat recovery container having an open top; a fourth step of opening the bottom of the intermediate container to allow the high-temperature granular material to fall and be charged into the heat recovery container from the top; A method for charging hot granular material into a heat recovery vessel having:

[0017] [7] The method for charging high-temperature granular material into a heat recovery vessel according to [6] above, wherein the feeder is a vibrating feeder.

[0018] [8] The method for charging high-temperature granular material into a heat recovery container according to [6] or [7] above, wherein the fourth step is carried out with a charging bell placed at the top of the heat recovery container.

[0019] [9] A method for charging high-temperature granular material into a heat recovery container described in any one of [6] to [8] above, wherein in the second step, the time required per 1 kg of the high-temperature granular material supplied from the feeder is 1 second or more and 60 seconds or less.

[0020]

[10] A method for charging high-temperature granular material into a heat recovery container described in any one of [6] to [9] above, wherein in the second step, the number of rotations of the intermediate container per 1 kg of the high-temperature granular material supplied from the feeder is 0.1 rotations or more and 8 rotations or less.

[0021]

[11] The method for charging high-temperature granular material into a heat recovery vessel according to any one of [6] to

[10] above, wherein the steel slag has a particle size range of 40 to 0 mm and a particle size distribution, using nominal openings of a metal mesh sieve as specified in JIS Z 8801-1:2019, of 100% by mass for a 53 mm sieve, 95 to 100% by mass for a 37.5 mm sieve, 50 to 80% by mass for a 19 mm sieve, 15 to 40% by mass for a 4.75 mm sieve, and 5 to 25% by mass for a 2.36 mm sieve.

[0022]

[12] The method for charging high-temperature granular material into a heat recovery vessel according to any one of the above [6] to

[11] , wherein the steel slag is steelmaking slag.

[0023]

[13] A method for charging high-temperature granular material into a heat recovery container according to any one of [6] to

[12] above; a step of passing a gas through the heat treatment vessel and recovering heat from the high-temperature granules by the gas; A method for recovering heat from hot granules comprising:

[0024]

[14] The method for recovering heat from high-temperature granular material according to

[13] above, wherein the gas is at least one selected from the group consisting of air, nitrogen, carbon dioxide, and water vapor.

[0025]

[15] A method for recovering heat from high-temperature granules according to

[13] above, wherein the gas contains one or both of carbon dioxide and water vapor, and in addition to the heat recovery, a reaction between the high-temperature granules and the gas is carried out. [Effects of the Invention]

[0026] The device and method for charging high-temperature granular materials into a heat recovery vessel of the present invention can suppress segregation of high-temperature granular materials, including steel slag, in the heat recovery vessel, thereby suppressing uneven flow of gas in the heat recovery vessel and achieving highly efficient heat recovery and carbonation. [Brief explanation of the drawings]

[0027] [Figure 1]1A and 1B are schematic diagrams of an apparatus 100 for charging high-temperature granular material into a heat recovery vessel according to one embodiment of the present invention, and illustrate a method for charging high-temperature granular material into a heat recovery vessel according to one embodiment of the present invention. [Figure 2] 1(A) and 1(B) are schematic diagrams showing methods of charging high-temperature granular materials into a heat recovery vessel according to Comparative Examples 1 and 2, respectively. [Figure 3] FIG. 1 is a schematic diagram showing an outline of a test of blowing air into the interior of a heat recovery container containing steel slag, which was conducted in the examples. [Figure 4] FIG. 10 shows wind speed measurement points at the top of the heat recovery vessel. [Figure 5] 1 is a graph (upper) showing the standard deviation of the flow rate at the top of the heat recovery container in Examples 1 and 2 of the invention and Comparative Examples 1 and 2, and a diagram (lower) showing the wind speed distribution at the top of the heat recovery container. DETAILED DESCRIPTION OF THE INVENTION

[0028] (Device and method for charging high-temperature granular material into heat recovery vessel) Referring to Figures 1(A) and (B), an apparatus 100 for charging high-temperature granular material into a heat recovery vessel 10 according to one embodiment of the present invention and a method for charging high-temperature granular material into a heat recovery vessel 10 according to one embodiment of the present invention will be described.

[0029] The charging device 100 is a device that charges high-temperature granular materials into a heat recovery container that contains high-temperature granular materials including steel slag and passes gas through the container to recover heat from the high-temperature granular materials using the gas.

[0030] The high-temperature granules are not particularly limited as long as they contain steel slag, and may consist of steel slag. The steel slag may be steelmaking slag or blast furnace slag. However, when carbonation treatment is performed in addition to heat recovery, it is preferable to use steelmaking slag that contains a large amount of free lime. The steelmaking slag may be converter slag or electric furnace slag. The blast furnace slag may be air-cooled slag or granulated slag.

[0031] The high-temperature granular material preferably contains, and more preferably consists of, steel slag meeting the CS-40 standard for road steel slag specified in JIS A 5015-2018. CS-40 has a particle size range of 40-0 mm, and a particle size distribution, based on the nominal mesh size of a metal mesh sieve specified in JIS Z 8801-1:2019, of 100% by mass passing through a 53 mm sieve, 95-100% by mass passing through a 37.5 mm sieve, 50-80% by mass passing through a 19 mm sieve, 15-40% by mass passing through a 4.75 mm sieve, and 5-25% by mass passing through a 2.36 mm sieve. Because of this wide particle size distribution, steel slag meeting the CS-40 standard is prone to segregation within the heat recovery vessel unless the charging device and charging method of the present invention are used. That is, the technical significance of the present invention is effectively exerted.

[0032] The hot particulates may include other particulates such as steel balls in addition to steel slag.

[0033] The temperature of the high-temperature granules at the stage of being charged into the heat recovery vessel 10 is preferably as high as possible from the viewpoint of heat recovery, and is preferably 1000°C or higher, and may be 1600°C or lower.

[0034] An apparatus 100 and a method for charging hot granular material according to one embodiment of the present invention will be described below, taking as an example a case in which steel slag Sg immediately after solidification and crushing is used as the hot granular material. Referring to Figures 1(A) and 1(B), the charging apparatus 100 charges steel slag Sg into a heat recovery vessel 10 and includes a vibrating feeder 20, an intermediate vessel 30, a turntable 40, and a lifter 50.

[0035] The vibrating feeder 20 supplies the steel slag Sg. In the first step of the charging method of this embodiment, the steel slag Sg is supplied by the vibrating feeder 20. Specifically, high-temperature steel slag Sg immediately after solidification and crushing is introduced into the vibrating feeder 20, which then supplies it little by little to the intermediate container 30 of the downstream equipment. The solidified slag can be crushed using a drum-type crusher such as a kiln, and the steel slag Sg discharged from this crusher is then fed into the vibrating feeder 20. While the vibrating feeder 20 is used in this embodiment, the present invention is not limited to this. Any feeder capable of supplying high-temperature granular material, such as a rotary feeder or screw feeder, may be used. By supplying the steel slag Sg little by little to the intermediate container 30 of the downstream equipment using the feeder, segregation of the steel slag Sg within the heat recovery container 10 can be ultimately suppressed.

[0036] The intermediate container 30 is a cylindrical container with an openable bottom 32 and an open top 34, and the bottom 32 and side 36 define the space inside the container. The dimensions of the intermediate container 30 are not particularly limited. The inner diameter of the intermediate container 30 can be, for example, in the range of 100 to 10,000 mm, and is preferably 30 to 100% of the inner diameter of the heat recovery container 10. The height of the intermediate container 30 can be set appropriately depending on the amount of steel slag Sg to be contained, but can be, for example, in the range of 100 to 60,000 mm. The material of the intermediate container 30 is not particularly limited, but for example, stainless steel plate can be used, and a refractory material may be provided on the inner wall. When performing carbonation treatment, acid refractory material and corrosion-resistant steel material can be used.

[0037] The structure of the bottom 32 of the intermediate container 30 is not particularly limited as long as it can be opened and closed. In this embodiment, the bottom 32 is made up of two flat plates, and the two flat plates are connected to the side portions 36 so that their connection portions with the side portions 36 face each other. The two flat plates are rotatable from their connection portions with the side portions 36, allowing the bottom 32 to be in a closed state or an open state. The two flat plates are closed to form the bottom 32, and when the two flat plates are opened, the bottom 32 is opened from the center line X of the intermediate container 30 toward the side portions 36.

[0038] In this embodiment, a turntable 40 is used as the rotation mechanism that rotates the intermediate container 30 about its center line X. However, the rotation mechanism is not limited to the turntable 40 that rotates itself, and may be any device that can impart power to the intermediate container 30 to rotate the intermediate container 30 about its center line X.

[0039] In the second step of the charging method of this embodiment, first, the intermediate container 30 is placed below the vibrating feeder 20 with the bottom 32 of the intermediate container 30 closed. Then, while the intermediate container 30 is rotated around its center line X by the turntable 40, the steel slag Sg supplied from the vibrating feeder 20 is charged into the intermediate container 30 from the top 34. This allows the steel slag Sg to be uniformly charged into the intermediate container 30, and ultimately prevents the steel slag Sg from segregating in the heat recovery container 10.

[0040] If the supply rate of the steel slag Sg from the vibrating feeder 20 is too high, the amount of steel slag Sg supplied will be excessive relative to the rotation speed of the intermediate container 30, resulting in localized accumulation of the steel slag Sg within the intermediate container 30 and segregation of the steel slag Sg. On the other hand, if the supply rate of the steel slag Sg from the vibrating feeder 20 is too low, the amount of steel slag Sg supplied will be too low relative to the rotation speed of the intermediate container 30, resulting in segregation of the steel slag Sg and an increase in process time. From this perspective, the time required per kg of steel slag Sg supplied as high-temperature granular material from the vibrating feeder 20 is preferably 1 second or more and 60 seconds or less, and more preferably 15 seconds or more and 25 seconds or less. Considering application to other granular materials or steel balls, the supply volume of the high-temperature granular material 100 cm , obtained from the mass / density, is considered to be 100 cm . 3 The time required for the perforation is preferably 0.3 seconds or more and 20 seconds or less, and more preferably 4 seconds or more and 9 seconds or less. These times can be adjusted by adjusting the feeding speed from the feeder, for example, by controlling the vibration frequency of the vibrating feeder 20.

[0041] If the rotation speed of the intermediate container 30 is too high, the steel slag Sg will accumulate on the wall of the intermediate container 30 due to centrifugal force, resulting in segregation of the steel slag Sg. On the other hand, if the rotation speed of the intermediate container 30 is too low, the centrifugal force will be too small, reducing the effect of the rotation on dispersing the steel slag, and resulting in segregation of the steel slag Sg. From this perspective, the rotation speed of the intermediate container 30 per kg of steel slag Sg supplied as high-temperature granular material from the vibrating feeder 20 is preferably 0.1 to 8 revolutions, more preferably 0.6 to 4 revolutions. Considering application to other granular materials or steel balls, the ratio of the supply volume of the high-temperature granular material per 100 cm obtained from the mass / density is 0.1 to 8 revolutions, and more preferably 0.6 to 4 revolutions. 3 The number of revolutions of the intermediate container 30 per revolution is preferably 0.03 revolutions or more and 3 revolutions or less, and more preferably 0.2 revolutions or more and 1.5 revolutions or less.

[0042] There is an appropriate balance between the supply rate of the steel slag Sg from the vibrating feeder 20 and the rotation speed of the intermediate container 30. If the rotation speed of the intermediate container 30 is too high compared to the supply rate of the steel slag Sg, the centrifugal force causes the steel slag Sg to deposit on the walls of the intermediate container 30, resulting in segregation of the steel slag Sg. Furthermore, fine powder is stirred up, causing dust generation. On the other hand, if the rotation speed of the intermediate container 30 is too low compared to the supply rate of the steel slag Sg, the centrifugal force becomes too small, reducing the effect of the rotation on dispersing the steel slag, and again resulting in segregation of the steel slag Sg. Therefore, it is preferable to simultaneously satisfy the preferred range of the rotation speed of the intermediate container 30 in the previous paragraph and the preferred range of the time required to supply the steel slag Sg in the paragraph two paragraphs before.

[0043] The size (inner diameter) of the intermediate container can be changed as desired depending on the amount of steel slag Sg to be supplied. However, if it is too large, the operating costs of the device increase, and if it is too small, the supply rate cannot be increased. Therefore, an appropriate size is preferable. The supply time of steel slag Sg is determined based on the above-mentioned supply volume of 100 cm. 3 When the time is 0.3 seconds or more and 20 seconds or less per unit time, the supply volume of steel slag Sg is 100 cm 3 The diameter required for a hit should be between 0.1cm and 1cm.

[0044] The peripheral speed of the intermediate container (movement speed of the inner wall) is expressed as circumference x rotation speed, and is preferably 0.05 m / s or more and 0.3 m / s or less.

[0045] The lifter 50, which serves as a transport mechanism, transports the intermediate container 30. In the third step of the charging method of this embodiment, the intermediate container 30 containing the steel slag Sg is transported and placed above the heat recovery container 10. At this time, it is preferable that the center line of the heat recovery container 10 and the center line of the intermediate container 30 coincide with each other and are vertically oriented. The transport mechanism is not limited as long as it can transport the intermediate container 30 from below the vibrating feeder 20 to above the heat recovery container 10, and it is preferable that the transport mechanism has a mechanism for moving the intermediate container 30 up and down, such as a crane or elevator.

[0046] The heat recovery vessel 10 is a heat recovery tank that contains steel slag Sg as high-temperature granules and passes gas through the interior to recover heat from the steel slag Sg using the gas. The heat recovery vessel 10 has a bottom 12 and a top 14 that can be opened and closed, and the bottom 12, top 14, and side 16 define the space inside the vessel. The bottom 12 of the heat recovery vessel 10 is closed when the steel slag Sg is charged and during heat recovery (and reaction), and is opened when the steel slag Sg is discharged from the heat recovery vessel 10 after heat recovery (and reaction). The top 14 of the heat recovery vessel 10 is open when the steel slag Sg is charged and is closed during heat recovery (and reaction) and when the steel slag Sg is discharged. The dimensions of the heat recovery vessel 10 are not particularly limited. The inner diameter of the heat recovery vessel 10 can be, for example, in the range of 100 to 10,000 mm. The height of the heat recovery vessel 10 can be set appropriately depending on the amount of steel slag Sg to be stored, but can be, for example, in the range of 100 to 60,000 mm. The material of the heat recovery vessel 10 is not particularly limited, but for example, stainless steel plate can be used, and refractory material can be provided on the inner wall. When carbonation treatment is performed, acid refractory material and corrosion-resistant steel material can be used.

[0047] In the fourth step of the charging method of this embodiment, with the top 12 of the heat recovery container 10 open, the bottom 32 of the intermediate container 30 is opened to allow the steel slag Sg, serving as high-temperature granular material, to fall and be charged into the heat recovery container 10 from the top 14. The mechanism for opening the bottom 32 of the intermediate container 30 is not particularly limited, but may be a method using a jig or an electric system.

[0048] In the embodiment described above, the high-temperature granules are fed from the feeder into a rotating intermediate container. The intermediate container is then positioned above the heat recovery container, and the bottom of the intermediate container is opened to allow the high-temperature granules to fall. This allows the high-temperature granules to be uniformly fed into the heat recovery container. This prevents segregation of the high-temperature granules, including steel slag, within the heat recovery container. This prevents uneven flow of gas within the heat recovery container, achieving highly efficient heat recovery and carbonation.

[0049] It is also possible to rotate the heat recovery container and charge the high-temperature granular material directly using a feeder without using an intermediate container, but this is not realistic because it would complicate the connection to the fixed piping and increase the equipment costs.

[0050] As shown in FIG. 1(B), the steel slag Sg is preferably charged with a charging bell 60 placed on the top 14 of the heat recovery vessel 10. The charging bell 60 is a conical, pyramidal, truncated conical, or truncated pyramidal member, and is preferably placed in the center of the top 14 so that the centerline of the cone is vertical. By using the charging bell 60, coarse particles gather in the center of the heat recovery vessel 10, while fine particles accumulate on the wall surface where wall flow is likely to occur. The main cause of gas drift is thought to be the phenomenon in which gas preferentially passes through the gap between the wall surface of the heat recovery vessel 10 and the high-temperature granular material. By using the charging bell 60 to create the particle distribution described above, the gap between the wall surface and the high-temperature granular material is reduced, making gas drift less likely to occur. The diameter of the charging bell is preferably in the range of 1 / 10 to 2 / 3 of the diameter of the heat recovery vessel 10. The angle of the side surface of the charging bell relative to the bottom surface is preferably in the range of 15 to 80 degrees. In order to further suppress the uneven flow of gas, it is also preferable to place a charging tube at the top 34 of the intermediate vessel 30 when charging the steel slag Sg into the intermediate vessel 30.

[0051] Note that a coke dry quenching (CDQ) system with a similar configuration to the present invention cools red-hot coke discharged from a coke oven with inert gas and generates high-temperature, high-pressure steam using the recovered heat. Japanese Patent Application Laid-Open Publication No. 2015-193819 describes a rotary bucket that rotates to uniformly collect the red-hot coke discharged from the coke oven. Japanese Patent Application Laid-Open Publication No. 2011-79992 also describes a CDQ system in which a bucket containing red-hot coke and having an opening / closing gate at the bottom is transported to above a chamber, and the opening / closing gate is then opened to drop the red-hot coke, which is then introduced into the chamber via a chute hopper.

[0052] However, there is a large difference in the caking properties between red-hot coke and steel slag, so CDQ equipment cannot be directly applied to heat recovery of steel slag. In the case of CDQ, red-hot coke discharged from the coke oven is directly received in a bucket. However, because steel slag has a lower viscosity than red-hot coke, if steel slag discharged from the crusher is directly fed into the intermediate container, as in CDQ, the steel slag will collapse. Therefore, it was decided to feed the steel slag into the intermediate container using a feeder.

[0053] In JP 2011-79992 A, the opening of the bottom gate is stopped midway and charging is performed at two different opening degrees. However, providing a movable part to adjust the opening degree at the part that comes into contact with the high-temperature red-hot coke increases equipment costs and makes the coke susceptible to heat damage. In contrast, in the present invention, uniform charging can be achieved by opening the bottom of the intermediate vessel all at once. Furthermore, while JP 2011-79992 A discloses a chute hopper provided between the bucket and the chamber, the present invention does not provide a chute hopper between the intermediate vessel and the heat recovery vessel.

[0054] JP 2015-193819 A specifies two bucket rotation speed settings: the first setting is 4.5 rpm or less, and the second setting is 4.5 rpm or more and 15 rpm or less. However, the centrifugal acceleration used to determine the rotation speed does not take into account the mass or density of coke. If applied directly to steel slag, which has a different density, the centrifugal force will be different from that of coke and cause segregation. In this invention, the concept of density is introduced, and the rotation speed of the intermediate vessel is set appropriately for the supply volume of hot granular material obtained from the mass / density.

[0055] (Method for recovering heat from hot granular materials) A method for recovering heat from high-temperature granules according to one embodiment of the present invention includes the method for charging high-temperature granules into the heat recovery vessel 10 according to the present embodiment described above, and a step of passing a gas through the inside of the heat treatment vessel 10 and recovering heat from the high-temperature granules using the gas. For example, room-temperature gas can be supplied into the heat treatment vessel 10 from the bottom 12 of the vessel, and the gas, which has recovered heat from the high-temperature granules and has been heated, can be recovered from the top 14 of the vessel 10, thereby recovering heat from the high-temperature granules using the gas.

[0056] The type of gas supplied into the heat treatment vessel 10 and finally discharged and recovered from the heat treatment vessel 10 is not particularly limited, but may be at least one selected from the group consisting of air, nitrogen, carbon dioxide, and water vapor. Heat can be recovered from the high-temperature granular material using these gases.

[0057] The type of gas is preferably one or both of carbon dioxide and water vapor. In this case, in addition to heat recovery, a reaction between the steel slag as high-temperature granules and these types of gases can be carried out as described below. In this case, the method for recovering heat from high-temperature granules according to this embodiment also serves as a method for reacting the high-temperature granules with the gas.

[0058] If the gas contains water vapor, the steel slag can be steam-aged. Steam aging is a process in which water vapor is supplied to high-temperature steel slag to hydrate the free lime (free-CaO) contained in the slag through the main reaction shown in equation (1) below. The resulting processed slag has undergone an expansion reaction through the steam aging process, making it suitable for shipping as steel slag for road use. CaO + H2O → Ca(OH)2···(1)

[0059] If the gas contains carbon dioxide, the steel slag can be carbonated. Carbonation is a process in which carbon dioxide (CO2) is supplied to high-temperature steel slag, and the free lime (free-CaO) contained in the slag is carbonated through the main reaction shown in equation (2) below. The resulting treated slag has undergone an expansion reaction due to the carbonation process, making it suitable for shipping as steel slag for road use. CaO + CO2 → CaCO3 (2) [Example]

[0060] In order to evaluate the segregation of steelmaking slag in the heat recovery vessel and the resulting uneven flow of gas, a cold laboratory test was conducted as follows.

[0061] (Examples 1 and 2) In Examples 1 and 2, room-temperature steelmaking slag was charged using the charging device and charging method of the present invention shown in Figures 1(A) and 1(B). Example 1 did not use a charging bell, while Example 2 used a charging bell (Φ100 mm). The steelmaking slag used was 0.5 kg for particles 53 to 37.5 mm, 9.5 kg for particles 37.5 to 19 mm, 11.0 kg for particles 19 to 4.75 mm, 4.5 kg for particles 4.75 to 2.36 mm, and 4.5 kg for particles less than 2.36 mm, for a total of 30.0 kg, which meets the CS-40 standard.

[0062] The intermediate vessel had an inner diameter of 200 mm and a height of 400 mm. The heat recovery vessel had an inner diameter of 300 mm and a height of 300 mm. The heat recovery vessel was pre-filled with Φ10 mm ceramic balls as a gas diffusion layer Ds to a height of 130 mm, and steelmaking slag was charged onto them using the charging method of the present invention. The vibration frequency of the vibrating feeder was set to 60 Hz. At this time, the time required for feeding 1 kg of steelmaking slag from the vibrating feeder was 14 seconds, and the feeding volume of steelmaking slag was 100 cm. 3 The time required for the hit was 4.5 seconds. The rotation speed of the intermediate container was 7.5 rpm. At this time, the number of rotations of the intermediate container per 1 kg of steelmaking slag fed from the vibration feeder was 1.7 rotations, and the steelmaking slag feed volume was 100 cm. 3 The number of rotations of the intermediate container per rotation was 0.6. Steel slag supply volume 100cm 3 The diameter of the hole is 0.50cm / 100cm 3 It was. The peripheral velocity of the intermediate vessel was 0.0785 m / s.

[0063] (Comparative Examples 1 and 2) In Comparative Examples 1 and 2, room-temperature steelmaking slag was charged according to the charging methods shown in Figures 2(A) and (B), respectively. That is, the steelmaking slag contained in a bucket was charged directly into the heat recovery vessel from one direction. Comparative Example 1 did not have a charging bell, and Comparative Example 2 had a charging bell (Φ100 mm). The steelmaking slag used had the same amount and particle size distribution as in Invention Examples 1 and 2. As in Invention Examples 1 and 2, the heat recovery vessel had an inner diameter of 300 mm and a height of 300 mm. The heat recovery vessel was pre-filled with Φ10 mm ceramic balls as a gas diffusion layer Ds to a height of 130 mm, and the steelmaking slag was charged on top of them.

[0064] [Evaluation of gas flow deviation] As shown in Figure 3, in Examples 1 and 2 and Comparative Examples 1 and 2, after steelmaking slag was charged into the heat recovery container, room temperature gas (air) was supplied into the container from the bottom at a flow rate of 300 NL / min, and the wind speed distribution was measured at the top of the heat recovery container. The wind speed distribution was measured as shown in Figure 4. That is, the horizontal plane at the top of the heat recovery container was divided into 56 sections, 7 in the radial direction and 8 in the circumferential direction, and the wind speed was measured at the center of each section (the black dots in Figure 4). The area of each section was A i (m 2 ), and wind speed is ν i (m / s), the standard deviation of the flow rate Q is calculated using the following formula: σ The smaller this value, the more the gas unevenness is suppressed. The results are shown in Figure 5.

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[0065] As shown in Figure 5, the standard deviation of the flow rate was 60 L / min or less in Examples 1 and 2, and 50 L / min or less in Example 2, which used a charging bell. This is thought to be because the segregation of steelmaking slag in the heat recovery vessel was suppressed. In contrast, in Comparative Examples 1 and 2, the standard deviation of the flow rate exceeded 100 L / min, indicating that the effect of the charging bell was minimal.

[0066] When the filling height of the steelmaking slag was measured for Invention Examples 1 and 2, it was found that in Invention Example 1, which did not have a charging bell, the center was higher than the edges, but in Invention Example 2, which did have a charging bell, the center was lower. It is thought that the use of the charging bell allowed fine slag to collect near the wall, suppressing wall flow. [Industrial Applicability]

[0067] The device and method for charging high-temperature granular materials into a heat recovery vessel of the present invention can suppress segregation of high-temperature granular materials, including steel slag, in the heat recovery vessel, thereby suppressing uneven flow of gas in the heat recovery vessel and achieving highly efficient heat recovery and carbonation. [Explanation of symbols]

[0068] 100 Charging device 10 Heat recovery vessel 12 Bottom of heat recovery vessel 14 Top of heat recovery vessel 16 Side of heat recovery vessel 20 Vibration feeder 30 Intermediate container 32 Bottom of intermediate container 34 Top of intermediate container 36 Side of intermediate container X Center line of intermediate container 40 Rotating table (rotating mechanism) 50 Lifter (transport mechanism) 60 Charging Bell Sg: Steel slag (high-temperature granular material) Ds Gas diffusion layer

Claims

1. 1. An apparatus for charging high-temperature granular materials including steel slag into a heat recovery container in which a gas is passed through the container while the high-temperature granular materials are contained, and for recovering heat from the high-temperature granular materials using the gas, comprising: a feeder for supplying the hot granular material; a cylindrical intermediate container having an openable bottom and an open top; a rotation mechanism that rotates the intermediate container about its center line; a conveying mechanism for conveying the intermediate container; and With the bottom of the intermediate container closed, the intermediate container located below the feeder can be rotated by the rotation mechanism, and the high-temperature granular material supplied from the feeder can be charged into the intermediate container from the top, The intermediate container containing the high-temperature granular material can be transported by the transport mechanism and placed above the heat recovery container having an open top, The bottom of the intermediate container can be opened to allow the high-temperature granules to fall, and the high-temperature granules can be charged into the heat recovery container from the top. A device for charging high-temperature granular material into a heat recovery vessel.

2. 2. The apparatus for charging hot granular material into a heat recovery vessel according to claim 1, wherein the feeder is a vibrating feeder.

3. 3. The device for charging hot granular material into a heat recovery vessel according to claim 1 or 2, wherein a charging bell is disposed at the top of the heat recovery vessel.

4. 3. The device for charging high-temperature granules into a heat recovery container according to claim 1 or 2, wherein the feeder is controlled so that the time required for feeding 1 kg of the high-temperature granules from the feeder is 1 second or more and 60 seconds or less.

5. 3. The device for charging high-temperature granular material into a heat recovery container as described in claim 1 or 2, wherein the rotation mechanism is controlled so that the number of rotations of the intermediate container per 1 kg of high-temperature granular material supplied from the feeder is 0.1 rotations or more and 8 rotations or less.

6. A method for charging high-temperature granular materials including steel slag into a heat recovery vessel in which the high-temperature granular materials are accommodated and a gas is passed through the vessel to recover heat from the high-temperature granular materials using the gas, the method comprising: a first step of feeding the hot granular material with a feeder; a second step of preparing a cylindrical intermediate container having an openable bottom and an open top, disposing the intermediate container below the feeder with the bottom of the intermediate container closed, and rotating the intermediate container about its center line as an axis to charge the high-temperature granular material supplied from the feeder into the intermediate container from the top; a third step of transporting the intermediate container containing the high-temperature granules and placing it above the heat recovery container having an open top; a fourth step of opening the bottom of the intermediate container to allow the high-temperature granules to fall and be charged into the heat recovery container from the top; A method for charging hot granular material into a heat recovery vessel having:

7. 7. The method of charging a heat recovery vessel with hot granular material according to claim 6, wherein the feeder is a vibratory feeder.

8. 7. The method for charging hot granular material into a heat recovery vessel according to claim 6, wherein the fourth step is carried out with a charging bell disposed at the top of the heat recovery vessel.

9. 7. The method for charging high-temperature granular material into a heat recovery container according to claim 6, wherein the time required for feeding 1 kg of the high-temperature granular material from the feeder in the second step is 1 second or more and 60 seconds or less.

10. 7. The method for charging high-temperature granules into a heat recovery container according to claim 6, wherein in the second step, the number of rotations of the intermediate container per 1 kg of the high-temperature granules supplied from the feeder is 0.1 rotations or more and 8 rotations or less.

11. The method for charging high-temperature granular material into a heat recovery container according to claim 6, wherein the steel slag has a particle size range of 40 to 0 mm and has a particle size distribution, in terms of nominal mesh openings of metal mesh sieves specified in JIS Z 8801-1:2019, of a 53 mm sieve passage rate of 100 mass%, a 37.5 mm sieve passage rate of 95 to 100 mass%, a 19 mm sieve passage rate of 50 to 80 mass%, a 4.75 mm sieve passage rate of 15 to 40 mass%, and a 2.36 mm sieve passage rate of 5 to 25 mass%.

12. 7. The method for charging hot granular material into a heat recovery vessel according to claim 6, wherein the steel slag is steelmaking slag.

13. A method for charging high-temperature granular material into a heat recovery vessel according to any one of claims 6 to 12; a step of passing a gas through the heat treatment vessel and recovering heat from the high-temperature granules by the gas; A method for recovering heat from hot granules comprising:

14. 14. The method for recovering heat from hot granules according to claim 13, wherein the gas is at least one selected from the group consisting of air, nitrogen, carbon dioxide, and water vapor.

15. 14. The method for recovering heat from high temperature particulates according to claim 13, wherein the gas contains one or both of carbon dioxide and water vapor, and in addition to the heat recovery, a reaction between the high temperature particulates and the gas is carried out.

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