JP2014085064A - Heat recovery system for coagulation slag and heat recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot carrier device and a hot carrier method for coagulation slag that can efficiently collect sensible heat of the coagulation slag.SOLUTION: An upper surface of molten slag 3 poured from a feeding device 4 into a casting mold 21 continuously transferred is fabricated at a horizontal transferring part 22a and the casting mold 21 is transferred horizontally while the fabrication is being carried out, the casting mold 21 is transferred up to a loading shoot 72 of a heat recovery device 7 at an oblique transferring part 22b in continuous with the horizontal transferring part 22a, and the formed coagulation slag 6 is loaded into the heat recovery device 7. With this operation, the coagulation slag 6 fabricated against irregularity is transferred to the heat recovery device 7 while being kept at high temperature to restrict reduction in temperature and thus it is possible to perform an efficient recovery of the sensitive heat from the coagulation slag 6.

Description

  The present invention relates to a solidified slag heat recovery system and a heat recovery method for recovering sensible heat of solidified slag formed by solidification molding of slag (mineral) discharged in a steel manufacturing process or the like.

In recent years, for the purpose of preventing global warming, energy saving is strongly demanded for manufacturing processes such as a steel manufacturing process in which a large amount of CO ₂ is generated. As one of the energy saving measures, exhaust heat recovery is effective. In particular, the exhaust heat in a mass production process such as a steel manufacturing process has a large amount of energy, so the energy saving effect obtained by exhaust heat recovery is very large.

  Since the sensible heat of the molten slag discharged in the steel manufacturing process has a magnitude of about 0.5 GJ per ton of pig iron, a large energy saving effect can be expected if the sensible heat of the molten slag can be recovered. However, most of the molten slag has been used as granulated sand or slag aggregate after undergoing a water granulation process or a slow cooling process, and the sensible heat of the molten slag is hardly utilized.

  As a technique for recovering the sensible heat of molten slag, Patent Documents 1 to 3 describe a technique for crushing slag. Patent Documents 4 to 5 describe techniques for recovering slag sensible heat by rapidly cooling molten slag on the roll surface and solidifying and forming the slag and supplying it to a heat recovery device.

  Patent Document 6 discloses a method of recovering sensible heat by solidifying and forming molten slag into a relatively thick shape using a caster, and charging the heat recovery device with the solidified slag in a high temperature state. Have been described. When the molten slag is solidified and molded in this way, the surface area per unit volume of the solidified slag becomes small, so the solidified slag is easy to keep warm, the variation in the temperature of the solidified slag is small, and the temperature of the solidified slag decreases due to transportation, etc. And can be supplied to the heat recovery device at a high temperature. Moreover, since it has thickness, it is easy to hold | maintain the center of the board thickness (solidification thickness) of solidification slag with high temperature, and it can supply to a heat recovery apparatus in the state which has high sensible heat.

  In addition, in Patent Document 7, in consideration of the case where the solidified slag is crushed to produce aggregate for concrete, etc., when the molten slag is solidified, irregularities are provided to increase the surface area of the solidified slag and crush it. A hot forming technique is described which sometimes makes it easy to break. Patent Document 8 describes a technique of heat recovery in which molten slag is granulated at the inlet of the solidification slag of the heat recovery apparatus and charged into the heat recovery apparatus to recover the sensible heat of the solidification slag.

JP 54-72204 A Japanese Patent Laid-Open No. 62-187146 JP 2004-238233 A JP-A-57-31784 JP 2001-180990 A JP-A-57-182086 JP 58-221379 A JP 2007-284761 A

  However, in the techniques described in Patent Documents 1 to 3, although a large heat recovery rate can be ensured, the slag after the air crushing treatment tends to be in the form of fine particles or fibers, and there is a problem in using the slag as a material. Remain. That is, the pulverized slag solidified into fine particles has a shape close to a true sphere and a small angle of repose, and therefore has poor handling properties. Further, in order to granulate slag having a particularly high viscosity, a large amount of gas injection is required, so that the cost of blower power and the like is increased.

  Further, according to the techniques described in Patent Documents 4 to 5, when the molten slag solidifies, it becomes a flake shape having a thickness of less than 5 mm. Therefore, when this solidified slag is granulated, the slag having a particle size of less than 5 mm increases. Applications are limited.

  Moreover, when the molten slag is solidified and molded into a relatively thick shape by the technique described in Patent Document 6, it is difficult to increase the heat recovery rate because the ratio of the surface area to the volume of the solidified slag is small. Moreover, when manufacturing such aggregate for concrete by crushing such solidified slag, since the thickness of the solidified slag before crushing is large, very large power is required for crushing, and the cost increases.

  On the other hand, the solidified slag formed by concavo-convex molding in consideration of crushing of the solidified slag by the technique described in Patent Document 7 has a large surface area and is easy to cool. When the solidified slag is crushed and transported to the heat recovery device, it takes about 1 hour to take into account the time until the slag after solidification and crushing is filled in the transport container, during which time the solidified slag cools. In addition, the amount of heat recovery is reduced and the temperature of the heat recovery medium cannot be increased. In that case, by further crushing the solidified slag before heat recovery, the surface area of the slag is increased and heat is easily dissipated in a short time before heat recovery, so that the amount of heat recovery is further reduced. On the other hand, in order to convey the solidified slag without crushing and crush it immediately before the heat recovery device, the size of the slag block is large and difficult to convey. That is, there is a problem that the heat recovery efficiency is low.

  This invention is made | formed in view of the above, Comprising: It aims at providing the heat recovery system and heat recovery method of the solidification slag which can collect | recover the sensible heat of solidification slag efficiently.

  In order to solve the above-described problems and achieve the object, a heat recovery system for solidified slag according to the present invention is provided with a solidified slag formed by pouring molten slag into a continuously conveyed mold. A solidification slag heat recovery system that recovers sensible heat of the solidification slag by entering, a horizontal conveyance unit that conveys the mold in a horizontal direction while performing molding on the upper surface of the slag poured into the mold, and A second transport for continuously transporting the mold to the solidification slag loading inlet of the heat recovery apparatus and charging the formed solidification slag into the heat recovery apparatus by inverting the mold. And a section.

  In the heat recovery system for solidified slag according to the present invention, in the above invention, the second transport unit transports to a height of a solidified slag loading inlet of the heat recovery device, and an inclined transport unit and / or a vertical transport unit. It is characterized by being.

  The heat recovery system for solidified slag according to the present invention is characterized in that, in the above invention, the average thickness of the slag poured into the mold is 10 to 30 mm.

  In the heat recovery system for solidified slag according to the present invention, in the above invention, the heat recovery device is a hot crushing device that crushes the solidified slag conveyed from the second conveying unit to the solidified slag loading inlet. It is characterized by providing.

  In the heat recovery system for solidified slag according to the present invention, in the above invention, the heat recovery device blows gas to a vertical moving layer of the solidified slag to perform heat exchange between the solidified slag and the gas. The sensible heat of the solidified slag is recovered by the above.

  The solidified slag heat recovery method according to the present invention recovers the sensible heat of the solidified slag by charging the solidified slag formed by pouring the molten slag into a continuously conveyed mold into a heat recovery device. A heat recovery method for solidified slag, wherein a horizontal conveyance step of conveying the mold in a horizontal direction while performing a molding process on an upper surface of the slag poured into the mold, and the mold continuously from the horizontal conveyance step. And a second transporting step of charging the formed solidified slag into the heat recovery device by reversing the mold and transporting it to the solidification slag loading inlet of the heat recovery device.

  According to the present invention, it is possible to efficiently recover sensible heat from the solidified slag by transporting the solidified slag formed with unevenness to the heat recovery device while maintaining a high temperature while suppressing temperature drop.

FIG. 1 is a diagram showing a schematic configuration of the heat recovery system of the present embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

  FIG. 1 is a diagram showing a schematic configuration of a heat recovery system for a solidified slag according to the present embodiment. As shown in FIG. 1, a heat recovery system 1 includes a casting machine 2 provided with a plurality of movable molds 21, a supply device 4 for supplying molten slag 3 from a blast furnace to the mold 21, and an upper surface of the slag. The apparatus includes a hot forming device 5 that imparts an uneven shape (plate thickness difference) and a heat recovery device 7 that charges the solidified slag 6 discharged from the mold 21 and collects the sensible heat of the solidified slag 6.

  The casting machine 2 includes a conveyance path 22 that moves a plurality of molds 21 arranged, and discharges the solidified slag 6 that is unevenly formed at a predetermined solidification slag discharge location B on the conveyance path 22. The supply device 4 supplies the molten slag 3 from the blast furnace to the mold 21 at the molten slag supply location A on the transport path 22. The hot forming apparatus 5 gives an uneven shape to the upper surface of the slag before the solidification of the molten slag 3 supplied to the mold 21 is completed. The conveyance path 22 is configured by connecting a horizontal conveyance section 22a and an inclined conveyance section 22b so as to circulate between a molten slag supply place A by the supply device 4 and a solidified slag discharge place B from the casting machine 2. Has been.

  As the hot forming device 5, the horizontal conveying unit 22 a is provided with a forming roll 5 a that can be moved up and down according to the conveyance of the mold 21, and the forming roll 5 a is mechanically uneven on the upper surface of the slag in the mold 21. Give. The reason why the forming roll 5a is provided in the horizontal conveyance portion 22a is that the distance between the mold 21 and the forming roll 5a needs to be kept constant. Further, the hot forming apparatus 5 is not limited to the forming roll 5a, and may be of a type that processes into a press shape, for example. In addition, the mold 21 can be made of a metal, a structure having a heat resistant and heat insulating structure with multiple layers such as inner surface castable construction, and the like.

  The inclined conveyance unit 22b is configured to convey the slag in the mold 21 to the solidified slag discharge location B at a predetermined height H. The inclined conveyance unit 22b may be a vertical conveyance unit that raises and lowers the mold 21 in the vertical direction. Alternatively, the inclined conveyance unit 22b may include a vertical conveyance unit that raises and lowers the mold 21 in the vertical direction. Further, the slag conveyance speed and conveyance distance in the conveyance path 22 are adjusted so as to ensure an appropriate air cooling time such that solidification is completed immediately before the slag in the mold 21 reaches the solidification slag discharge location B. The solidified slag discharge place B is provided with an appropriate solidified slag discharger, and the solidified slag 6 is sequentially discharged at the solidified slag discharge place B as the mold 21 is reversed.

  The supply device 4 supplies the molten slag 3 to the mold 21 so that the average thickness is 10 to 30 mm. When the average thickness of the slag is less than 10 mm, the particle size of the solidified slag after crushing becomes less than 10 mm, and the yield of the slag aggregate decreases. On the other hand, if the average thickness of the slag exceeds 30 mm, the generation of pores cannot be suppressed during cooling, and the quality of the slag aggregate deteriorates.

  The heat recovery device 7 includes a hot crushing device 71 for crushing the solidified slag 6 discharged from the mold 21, a charging chute 72 for charging the crushed solidified slag 6 into the heat recovery device 7, and a substantially cylindrical shape. And a vertical moving layer 73 formed. The vertical moving layer 73 conveys the solidified slag 6 charged from above to below. The heat recovery device 7 collects sensible heat of the solidified slag 6 by blowing gas (gas) as a heat recovery medium from below to above the vertical moving bed 73 and exchanging heat between the solidified slag 6 and the gas. To do.

  The charging chute 72 functions as a solidified slag charging inlet that is an inlet of the solidified slag 6 to the heat recovery device 7, is disposed so as to be connected to the solidified slag discharge place B, and is solidified discharged from the casting machine 2. The slag 6 is charged immediately after discharge. That is, the height H of the solidified slag discharge location B is adjusted according to the height of the charging chute 72. A hot crushing device 71 is disposed on the charging chute 72 and crushes the solidified slag 6 that has been unevenly formed discharged from the hot conveying device 1 and charges the solidified slag 6 into the heat recovery device 7. Note that the charging chute 72 is not necessary when the solidified slag 6 is charged from directly above the heat recovery device 7. In that case, the hot crushing device 71 as the solidification slag loading inlet is disposed directly above the vertical moving bed 73, and the height H of the solidification slag discharge location is adjusted according to the height of the hot crushing device 71. Is done.

  According to the heat recovery system 1 of the present embodiment configured as described above, the shortest air cooling time is ensured by the inclined conveyance unit 22b with respect to the slag formed uneven by the horizontal conveyance unit 22a, and the predetermined height H Since the slag is completely solidified immediately before reaching the solidified slag discharge location B, the solidified slag 6 having an uneven shape and an increased surface area is discharged from the casting machine 2 immediately after the solidification is completed, and promptly supplied to the heat recovery device 7. Can be charged. For this reason, according to the heat recovery system 1 of the present embodiment, the solidified slag 6 that is unevenly formed and tends to decrease in temperature is conveyed to the heat recovery device 7 at a high temperature, and the sensible heat is efficiently recovered from the solidified slag 6. Can do. In addition, since the solidified slag 6 is charged into the heat recovery device 7 after crushing, a gap is generated between the laminated solidified slags 6, a heat recovery gas flow path can be secured, and the heat recovery rate is improved. Further, since the solidified slag 6 is provided with an uneven shape and can be easily crushed to an appropriate size, a good slag aggregate can be obtained and the slag can be efficiently used. Therefore, according to the heat recovery system 1 of the present embodiment, it is possible to save energy in the steel manufacturing process.

  The conveyance path 22 of the present embodiment can also be applied when the heat recovery device 7 is replaced with CDQ (coke dry fire extinguishing equipment) and high temperature coke is charged into the CDQ.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to these, and various modifications according to the specifications and the like are within the scope of the present invention. It is obvious from the above description that various other embodiments are possible within the scope of the above.

DESCRIPTION OF SYMBOLS 1 Hot transfer apparatus 2 Casting machine 21 Mold 22 Transfer path 22a Horizontal transfer part 22b Inclined transfer part (2nd transfer part)
DESCRIPTION OF SYMBOLS 3 Molten slag 4 Supply apparatus 5 Hot forming apparatus 5a Forming roll 6 Solidified slag 7 Heat recovery apparatus 71 Hot crushing apparatus 72 Charging chute A Molten slag supply place B Solidified slag discharge place H Height of solidified slag discharge place

Claims (6)

A solidified slag heat recovery system that recovers sensible heat of the solidified slag by charging the solidified slag formed by pouring molten slag into a continuously conveyed mold,
A horizontal transport unit that transports the mold in a horizontal direction while performing molding on the upper surface of the slag poured into the mold;
A second transport for continuously transporting the mold to the solidification slag loading inlet of the heat recovery apparatus and charging the formed solidification slag into the heat recovery apparatus by inverting the mold. And
A heat recovery system for solidified slag, comprising:   2. The heat recovery of the solidified slag according to claim 1, wherein the second transfer unit is an inclined transfer unit and / or a vertical transfer unit that transfers to a height of a solidification slag loading inlet of the heat recovery device. system.   The heat recovery system for solidified slag according to claim 1 or 2, wherein an average thickness of the slag poured into the mold is 10 to 30 mm.   The said heat recovery apparatus is equipped with the hot crushing apparatus which crushes the solidification slag conveyed from said 2nd conveyance part in the said solidification slag loading inlet. The heat recovery system for solidified slag as described.   The heat recovery device recovers sensible heat of the solidified slag by blowing gas to a vertical moving layer of the solidified slag and performing heat exchange between the solidified slag and the gas. The heat recovery system of the solidification slag of any one of -4. A solidified slag heat recovery method for recovering sensible heat of the solidified slag by charging the solidified slag formed by pouring molten slag into a continuously conveyed mold,
A horizontal conveyance step of conveying the mold in a horizontal direction while performing molding on the upper surface of the slag poured into the mold;
A second transport for continuously transporting the mold to the solidification slag loading inlet of the heat recovery apparatus and charging the formed solidification slag into the heat recovery apparatus by reversing the mold from the horizontal transport step. Steps,
A method for recovering heat of solidified slag, comprising:

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