JP2012207828A - Vertical baking furnace - Google Patents

Abstract

An object of the present invention is to provide a vertical firing furnace that sufficiently supplies heat for firing to a raw material without increasing the height of the furnace body even when the processing capacity is increased.
SOLUTION: A preheating cylinder 12 that forms a preheating space above the hearth 11 and a firing cylinder 13 that forms a baking space below the hearth 11 are provided, and the preheating space has a drop opening 11A below the furnace lid. And the firing space is formed in the space of the firing cylinder 13 extending downward from the periphery of the drop opening 11A of the hearth 11, and the furnace The lid 14 is provided with a heating device 15 for injecting combustion gas or high-temperature gas toward the preheating space, and the firing cylinder 13 is a barrier portion extending radially inward from the inner surface of the firing cylinder 13 at an intermediate position in the height direction. 13A is provided at a plurality of positions in the circumferential direction, and a sub-heating device 20 that injects combustion gas or high-temperature gas into a space formed directly below the barrier portion 13A is provided on the peripheral wall of the firing cylinder 13.
[Selection] Figure 1

Description

  The present invention relates to a vertical firing furnace.

  As this type of firing furnace, one disclosed in Patent Document 1 is known.

  The vertical firing furnace of Patent Document 1 includes a vertical tubular furnace body having a preheating cylinder body that forms a preheating space above the hearth and a firing cylinder body that forms a firing space below the hearth. In the mold firing furnace, the preheating space is provided below the furnace lid provided with the heating device, extending inwardly from the inner surface of the furnace body and extending above the outer peripheral edge of the hearth having a drop opening at the center. A firing space is formed in the space of the cylindrical body, and the firing space extends downward from the periphery of the drop opening of the hearth.

  A burner for injecting combustion gas toward the preheating space is provided at the central axis position of the furnace lid, and the firing cylinder is located at an intermediate position in the height direction from the inner surface of the firing cylinder. Are provided at a plurality of positions in the circumferential direction. The plurality of bridges are connected at the central axis position of the firing cylinder.

  In such a vertical firing furnace of Patent Document 1, the raw material on the hearth is preheated on the surface layer facing the combustion gas, and is pushed out radially inward by a pusher provided above the hearth from the drop opening. It falls into the firing space of the firing cylinder. In the deposited layer of the raw material dropped from the drop opening of the hearth and deposited in the firing space, firing of the raw material is promoted in the deposited layer by the heat held by itself. The raw material that has been baked contacts the cooling air that rises in the calcination space and descends while being cooled, and is discharged as a product from a discharge tube provided in the lower portion of the calcination tube.

JP2009-068821

  However, the vertical firing furnace of Patent Document 1 has room for improvement in structure and function.

  In the vertical firing furnace of the type disclosed in Patent Document 1, if the processing capacity of the raw material is to be increased, the heating and firing time must be lengthened accordingly, and the height of the furnace body is increased. . In addition, the hearth raw material is preheated only on the surface of the deposited layer and falls from the surface side to the firing space, but the preheating is not sufficient, and it is not fired sufficiently while descending in the firing space. There is also.

  In view of these points, the present invention provides a vertical firing furnace capable of sufficiently providing heat for firing to a raw material without increasing the height of the furnace body even if the processing capacity is increased. The task is to do.

  A vertical firing furnace according to the present invention includes a vertical cylindrical furnace body having a preheating cylinder body that forms a preheating space above the hearth and a firing cylinder body that forms a firing space below the hearth.

  In such a vertical firing furnace, in the present invention, the preheating space is below the furnace lid provided with the heating device and extends radially inward from the inner surface of the furnace body and above the outer peripheral edge of the hearth having a drop opening at the center. Formed in the space of the preheating cylinder that is provided to extend, and the firing space is formed in the space of the firing cylinder that extends downward from the periphery of the drop opening of the hearth, and is directed to the furnace cover toward the preheating space. A heating device for injecting combustion gas or high-temperature gas is provided, and the fired cylinder is provided at a plurality of positions in the circumferential direction with barrier portions extending radially inward from the inner surface of the fired cylinder at an intermediate position in the height direction. In addition, a sub-heating device for injecting combustion gas or high-temperature gas into a space generated immediately below the barrier portion is provided on the peripheral wall of the firing cylinder.

  According to the vertical firing furnace of the present invention having such a configuration, the raw material that is supplied onto the hearth to form the deposited layer is the surface of the deposited layer by the combustion gas or high-temperature gas injected from the heating device to the preheating space. Is preheated by heating. The raw material on the surface of the preheated deposition layer falls by the pusher through the drop opening of the hearth, and then fires after passing between the barrier portions provided on the inner wall surface of the firing cylinder at a plurality of positions in the circumferential direction. A deposited layer is formed by reaching the bottom of the cylinder. The upper surface of the deposited layer in the firing space is positioned above the barrier portion of the firing cylinder.

  In the deposited layer in the firing space, the barrier portion is present below the upper surface of the deposited layer, so that a space in which no raw material is present is formed immediately below the barrier portion. In the present invention, combustion gas or high-temperature gas is injected from this auxiliary heating device into this space. Therefore, the raw material in the firing space is replenished with heat during the firing. Thus, even if the height of the furnace body is lower than the conventional one and the retention of the raw material in the firing cylinder is short, firing is sufficiently promoted.

  In the present invention, the barrier portions provided at a plurality of positions in the circumferential direction of the firing cylinder extend inward in the radial direction and can be connected to each other at the central axis position of the firing cylinder to form a bridge. .

  In a vertical firing furnace, the bridge is often provided to reinforce the firing cylinder. In other words, in the present invention, by injecting combustion gas or high-temperature gas from the sub-heating device into the space where there is no raw material formed directly under such a bridge, the raw material in the middle of firing is promoted for firing. Can supply heat.

  As described above, the present invention supplies the combustion gas or the high temperature gas from the sub-heating device to the space in the absence of the raw material formed immediately below the barrier portion provided in the firing cylinder, As a result, the raw material can be sufficiently fired even if the residence time in the firing cylinder for firing is short, and the processing capacity is increased. It is not necessary to increase the height of the firing cylinder, and in this respect, the furnace body, that is, the vertical firing furnace, can be downsized in the height direction.

It is a longitudinal cross-sectional view of the vertical firing furnace as embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, a furnace body 10, which has a bowl-shaped cylindrical shape that can be kept stationary without being rotated and is mainly made of refractory bricks, has an annular plate-like hearth 11 having a drop opening 11 </ b> A formed in the center in the radial direction. The preheating cylinder 12 extends upward from the outer peripheral edge of the hearth 11 and the firing cylinder 13 extends downward from the inner peripheral edge of the hearth 11, that is, the peripheral edge of the drop opening 11A. Pushers 11B that reciprocate in the radial direction at a plurality of positions in the circumferential direction are provided immediately above the hearth 11. In the present embodiment, the upper and lower pushers 11B are provided as a set.

  The preheating cylinder 12 is directed upward from the outer peripheral edge of the hearth 11, and an annular plate-shaped top plate portion 12 </ b> A is attached to an upper end edge thereof. The top plate portion 12A extends radially inward from the upper end edge of the preheating cylinder 12, and the inner cylinder portion 12B hangs from the inner peripheral edge thereof. The lower end of the inner cylinder portion 12B is fixed to the outer peripheral portion of the furnace lid 14, and the inner cylinder portion 12B supports the furnace lid 14 via an annular cooling portion 14A provided on the outer peripheral portion of the furnace lid 14. is doing. The cooling unit 14A forms a duct-shaped ring body that supports the furnace lid 14, and a cooling medium, for example, cooling water circulates therein, so that the outer peripheral part of the furnace lid 14 and the inner cylinder part 12B The lower end portion is cooled to prevent the support structure of the furnace lid 14 from being weakened.

  The furnace lid 14 is provided with a burner 15 for injecting fuel and air into the furnace body as a heating device at the position of the central vertical axis of the furnace lid 14. In the present invention, the burner 15 as a heating device may be liquid fuel, gas fuel, or solid fuel regardless of the type of fuel. Alternatively, the heating device may be configured to inject a gas heated to outside the furnace into the furnace body.

  The preheating space surrounded by the top plate portion 12A, the inner cylinder portion 12B, the preheating cylinder 12 and the hearth 11 is a space for depositing the raw material M such as limestone to be preheated on the hearth 11 before firing. And contributes to the preheating of the raw material M especially in the lower part of the preheating space. In the upper part of this preheating space, the raw material supply pipe 17 is connected to the top plate part 12A. The raw material supply pipes 17 are provided at a plurality of positions in the circumferential direction of the top plate part 12A. Each raw material supply pipe 17 is branched into two outside the furnace body above the top plate part 12A. Is a raw material input pipe 17A that is inclined, and the other is an exhaust pipe 17B that hangs upward. The plurality of raw material input pipes 17 </ b> A are open and connected to the bottom wall 18 </ b> A of the raw material storage tank 18 at their upper ends. The raw material storage tank 18 is partitioned into an upper space and a lower space by a partition plate 18B, and both spaces communicate with each other through a short cylinder 18C that hangs down from the partition plate 18B. Further, the lid plate of the raw material storage tank 18 is provided with a filling port 18D that can be opened and closed. The filling port 18D is opened and used for filling the raw material M into the upper space in the tank from the outside as appropriate. The raw material M supplied to the upper space falls to the lower space through the short cylinder 18C.

  A plurality of exhaust pipes 17B branched upward from the raw material input pipe 17A are connected to an annular duct 19 provided so as to surround the raw material storage tank 18 at the upper end of the exhaust pipe 17B. The duct 19 is connected to a suction device (not shown) such as a blower through the suction port 19A.

  A fired cylinder 13 made of a heat-resistant material in a cylindrical shape that hangs down from the periphery of the drop opening 11A of the hearth 11 is formed in a cylindrical shape downward after being expanded in the downward direction at the upper part. The cooling cylinder 13B is provided in a lower part of the cooling cylinder 13B. On the inner surface of the firing cylinder 13, arch-shaped bridges 13 </ b> A are provided at a plurality of positions in the circumferential direction at intermediate positions in the vertical direction. These bridges 13A are made of refractory bricks similarly to the furnace body 10, and when viewed from above, extend from the inner surface position of the fired cylinder 13 toward the central axis position, and the bridges 13A are connected to the central axis line. Linked in position. In other words, the plurality of bridges 13 </ b> A extend radially outward from the central axis position and reach the inner surface of the firing cylinder 13.

  The firing cylinder 13 is formed with a sub-heating space 16 that sunk radially outward in the circumferential wall at least at the position of the bridge 13A in the circumferential direction and at a position directly below the bridge 13A in the height direction. Yes. The sub-heating space 16 may have an annular shape that is continuous in the circumferential direction. The sub-heating space 16 is provided with a sub-heating device 20 attached to the outer wall, and fine carbon fuel and air are injected into the sub-heating space 16 as heating gas. Above the bridge 13A, a temperature sensor 21 is provided on the outer wall. The temperature of the raw material above the bridge 13A is detected, and the injected fuel and air of the sub-heating device 20 are detected according to the detected temperature. The amount of can be adjusted.

  From the lower part of the firing cylinder 13, a cooling cylinder 13B having a taper shape with a diameter reduced downward is suspended, and a cylindrical discharge cylinder 22 is suspended from the cooling cylinder 13B. The lower part of the discharge tube 22 has a small diameter, and an inclined extraction tube 23 extends downward therefrom. In the take-out pipe 23, rotary dampers 23A, 23B, and 23C are provided at three different positions in the upper and lower directions, and the upper and lower dampers 23A and 23C and the intermediate damper 23B have different opening and closing timings. Yes.

  An intake pipe 24 that receives cooling air from the outside is provided in a range where the cooling cylinder 13B moves to the discharge cylinder 22. The air receiving tube 24 is bent in an L shape and extends upward, and a two-stage umbrella-shaped gas 25 is attached to the upper end thereof. Due to the umbrella-shaped gas 25, the raw material does not enter the upper end opening of the receiving pipe 24, and the cooling air is distributed and sent from the upper end opening to the surroundings. A stepped sliding guide body 26 is attached to the outer surface of the vertical portion of the air receiving tube 24. The sliding guide body 26 has an annular step formed on the upper surface, and has a diameter that is lower at the lower stage than at the upper stage. Preferably, the sliding guide body 26 receives a driving force from the outside and rotates slowly around the intake pipe 24. The raw material cooled after firing reaches the lower part of the discharge tube 22 by sliding down the upper surface of the sliding guide 26 in order.

  Next, with respect to the apparatus of this embodiment having such a configuration, the principle that raw materials are charged into the furnace and fired in the furnace will be described.

  (1) The raw material M which is a firing object such as limestone supplied from the filling port 18D to the upper space of the raw material storage tank 18 is stored on the partition plate 18B, and the lower space of the raw material storage tank 18 from the plurality of short cylinders 18C. And dropped through a plurality of raw material charging pipes 17A extending obliquely downward from the bottom wall 18A and deposited on the hearth 11 in the furnace body 10. The deposited layer of the raw material M on the hearth 11 forms a free surface with an angle of repose inward in the radial direction of the furnace body 10.

  (2) Fuel and air are injected from a plurality of burners 15 as heating devices provided in the furnace lid 14, the fuel is burned, and the flame is jetted downward.

  (3) The raw material M forming a deposition layer on the hearth 11 is heated by the flame on its free surface and preheated, and is sequentially dropped into the firing cylinder 13 from the drop opening 11A by the operation of the pusher 11B. When the preheated raw material M falls from the drop opening 11A, it passes between the bridges 13A provided as barrier portions at a plurality of positions in the circumferential direction, and further falls to rise above the bridge 13A in the fired cylinder 13. Deposited with a free surface in place. Immediately below the bridge 13A, a space free of raw materials is formed. That is, the free surface of the deposited layer of the raw material exists in the space. Combustion gas from the sub-heating device 20 is injected into the space, and the deposited layer is heated on the free surface facing the space to replenish heat and promote firing.

  (4) On the other hand, the external air taken in from the air receiving tube 24 enters the deposition layer from the partial gas 25 as cooling air through the air receiving tube 24, and while cooling the raw material whose firing has sufficiently progressed, It rises in temperature, reaches the preheating space, and contributes to combustion as part of the combustion air.

  (5) A part of the combustion gas in the preheating space flows from the free surface into the deposition layer of the raw material M on the hearth 11 and contributes to preheating. Since the annular duct 19 provided outside the furnace is sucked by an external blower (not shown), part of the combustion gas that permeates the deposition layer of the raw material M on the hearth 11 exchanges heat with the raw material M. Then, the temperature of the exhaust pipes 17 </ b> B is raised and exhausted through the annular duct 19.

  (6) The raw material M thus baked and cooled is cooled while descending the discharge tube 22, slides down the take-out pipe 23, and is taken out as a product through the dampers 23A, 23C and 23B which are alternately opened.

  The invention is not limited to the form shown and described, but can be variously modified. For example, both the heating device and the sub-heating device can be a device that injects fuel to generate combustion gas, or a device that injects as a high-temperature gas into the furnace after burning outside the furnace. As the fuel, any of liquid fuel, gaseous fuel, and solid fuel, or a mixture thereof can be used. As the solid fuel, pulverized coal suitable for injection can be used.

  Further, the plurality of barrier portions may not be the above-described bridge portion, but may protrude radially inward from the peripheral wall of the fired cylindrical body, and may not be connected at the central axis position. Further, the space for receiving the heating gas from the barrier portion and the sub-heating device may be provided at a plurality of positions in the vertical direction, in which case the upper barrier portion and the upper and lower barrier portions are at different positions in the circumferential direction. It is preferable to be provided.

  In the illustrated example, the hearth is non-rotating, but the present invention can also be applied to a vertical furnace in which the hearth rotates around the vertical central axis.

DESCRIPTION OF SYMBOLS 10 Furnace 11 Hearth 11A Falling opening 12 Preheating cylinder 13 Firing cylinder 13A Barrier part (bridge)
14 Furnace 15 Heating device (burner)
20 Sub-heating device

Claims (2)

In a vertical firing furnace comprising a vertical cylindrical furnace body having a preheating cylinder forming a preheating space above the hearth and a firing cylinder forming a firing space below the hearth,
The preheating space is within the space of the preheating cylinder provided below the furnace lid where the heating device is provided and extending radially inward from the inner surface of the furnace body and above the outer peripheral edge of the hearth having a drop opening at the center. Formed in the space of the firing cylinder extending downward from the periphery of the drop opening of the hearth,
The furnace cover is provided with a heating device for injecting combustion gas or high-temperature gas toward the preheating space,
The fired cylindrical body is provided with barrier portions extending radially inward from the inner surface of the fired cylindrical body at a plurality of positions in the circumferential direction at an intermediate position in the height direction, and the barrier portion is formed on the peripheral wall of the fired cylindrical body. A vertical firing furnace characterized in that a sub-heating device for injecting combustion gas or high-temperature gas into a space formed immediately below is provided.   2. The scissors according to claim 1, wherein the barrier portions provided at a plurality of positions in the circumferential direction of the firing cylinder extend inward in the radial direction and are connected to each other at a central axis position of the firing cylinder to form a bridge. Mold firing furnace.

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