JPH0143231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a firing furnace, and more particularly to a double inclined firing furnace for firing fine grain materials such as limestone.

[Prior art]

Conventional firing furnaces of this type have an asymmetric cross section in the vertical direction and a rectangular cross section in the horizontal direction, and have the following disadvantages in terms of structure and furnace operation. In other words, since it has an asymmetrical shape with an unstable vertical cross section and is not a stable structure that can stand on its own, it requires a large-scale structure to prevent falls and reinforcing members for each part, which requires a large amount of steel. material costs and processing and assembly costs are required.
Furthermore, since the horizontal cross section is rectangular, not only does the number of bricks required per cross-sectional area increase, but also walls are formed on both sides, creating a speed difference in the flow of gas and raw stone. In other words, gas blows through in the area that is in contact with the wall of the furnace, and the falling speed of the rough stone increases, while in the central area, the gas flow is poor and the falling speed of the rough stone decreases, resulting in uneven firing. It turns out. Furthermore, due to the structure, it was not possible to increase the size in the long side direction, and there was a limit to increasing the size.

[Summary of the invention]

In view of these drawbacks of conventional firing furnaces, the present invention has developed a truncated conical part formed in a cylindrical inner cylinder and a corresponding part formed in a truncated conical part of a cylindrical outer cylinder fitted around the inner cylinder. In combination with the bulge,
The present invention provides a firing furnace based on a furnace body structure comprising a plurality of firing zones.

[Embodiments of the invention]

Hereinafter, one embodiment of the firing furnace according to the present invention will be described in detail with reference to the accompanying drawings.

In the accompanying drawings, the inner cylinder 1 having a cylindrical cross section is
A truncated conical part 2 is formed in the vertically intermediate part to protrude in the circumferential direction and is held on a base 3, and the interior below the truncated conical part 2 is supplied with hot air via a cooling passage 4 around the periphery. A flue 5 is provided, the lower part of the flue 5 is extended below the base frame 3 and connected to the hot air generating furnace 6, and the upper part is connected to the lower combustion chamber 7 formed under the truncated conical part 2. An exhaust flue 8 is formed inside from the opening around the upper part of the truncated conical part 2, and the exhaust flue 8 and the cooling passage 4 are connected to ducts 9 and 10 on the side of the upper end.
It has been taken out.

Further, an outer cylinder 11 having a cylindrical cross section and fitted around the inner cylinder 1 is provided with an upper combustion chamber in the upper part between the truncated conical part 2 and the truncated conical part 2. The chamber 13 is held on the base frame 3 with a bulge 12 formed in the circumferential direction to form the lower combustion chamber 7 at the bottom thereof, and a skirt for receiving raw ore is provided at the top opening of the furnace. Shape introduction tube 1
4 and a duct 15 for discharging the exhaust gas after firing the raw stone, upper burners 16 are arranged at multiple locations on the side of the upper combustion chamber 13, and a circulating gas suction port 17 is provided on the lower side.
There is a take-out opening 18 at the bottom which communicates with the product take-out device 19 through the base frame 3.
has been formed.

Therefore, due to the combination of the furnace structure consisting of the inner cylinder 1 and the outer cylinder 11, the furnace includes, from above, a preheating zone A, an upper firing zone B, a lower firing zone C, a cocurrent firing zone D, and a product cooling zone. Each band E is configured separately.

A requiperator 20 is connected to the duct 9 taken out from the exhaust flue 8, and a primary operating air blower 21 is connected to the requiperator 20.
The primary working air from the
The secondary air is supplied to the upper burner 16, and the other working air is supplied to the injector 23 connected to the circulating gas suction port 17, respectively. Further, secondary air that also serves as cooling air from the secondary air blower 24 is supplied to the cooling passage 4, and the secondary air that has been heat exchanged through the cooling passage 4 passes from the duct 10 through the header 25. One part is supplied to the upper burner 16, and the other part is supplied to the hot air generating furnace 6. Further, the cooling air, which also serves as tertiary air, sucked into the product take-out device 19 from the duct 26 cools the product in the device 19 and the take-out opening 18, and is heat-exchanged through the product cooling zone E. Injector 23 and header 2 from circulating gas suction port 17
7 and then reaches a hot air generating furnace 6. A fuel pump 2 is connected to the hot air generating furnace 6 and the upper burner 16.
Fuel is supplied from 8, and the high-temperature combustion gas obtained by combustion in the hot air generating furnace 6 is blown out into the lower combustion chamber 7 through the hot air flue 5, and a part of it flows back into the cocurrent firing zone D. The other part passes through the lower firing zone C, and then passes through the upper firing zone B together with the high temperature combustion gas from the upper burner 16, and a part of it passes through the exhaust flue 8 and duct 9. After passing through the recuperator 20, the other parts are sucked into the exhaust blower 29 from the preheating zone A through the duct 10, and are discharged from the exhaust blower 29 into the atmosphere through an exhaust gas dust collector (not shown).

Further, in the upper part of the furnace top, there is a surge hopper 31 having an upper damper 32 for air isolation, which receives the rough stone fed from the rough stone carrying conveyor 30, and a cutting feeder 33 that cuts the rough stone from the surge hopper 31. , a rotary chute-type rough stone charging device 34 that accepts the raw stone to be cut from the lower damper 35 for air insulation and uniformly charges it into the skirt-shaped introduction tube 14, and a sounding device 36 that measures the raw stone input level and performs charging control. In addition, a product hopper 37 that once receives the product from the pre-air product discharge device 19, a discharge damper 38 for the air break, a rotary table 39 that collects the products from the product hopper 37, and a product discharge conveyor. 40.

In the case of this embodiment, a predetermined amount of raw ore fed by the carry-in conveyor 30 is temporarily stored in the surge hopper 31 from the upper damper 32 that opens when the lower damper 35 is closed. A certain amount of raw ore is periodically cut out from this surge hopper 31 by a cut feeder 33, received into the raw ore input device 34 from a lower damper 35, and introduced into a skirt shape at the top of the furnace by the rotating chute of the device 34. The lower damper 35 closes after it is evenly poured into the cylinder 14.

The raw ore flowing down through the furnace from the skirt-like introduction tube 14 reaches the upper firing zone B while being preheated by the combustion exhaust gas in the preheating zone A. In this upper firing zone B, the raw ore is fired by the combustion gas from the upper burner 16 in the upper combustion chamber 13, which is formed by the angle of repose of the falling raw ore.
It flows down on the outer peripheral inclined surface of the truncated conical part 2 and enters the lower firing zone C. Also, in this lower firing zone C,
Similarly, in the lower combustion chamber 7, a space is formed by the angle of repose of the falling rough stone, from the hot air generating furnace 6 to the hot air flue 8.
The fired gas is fired again by the combustion gas blown out through the bulging portion 12, and once again flows down on the sloped surface of the lower inner circumference of the bulging portion 12 to reach the parallel flow firing zone D. In this co-current firing zone D, part of the combustion gas in the lower combustion chamber 7 is sucked into the injector 23 and flows back, as will be described later, where the firing is performed and the product is After reaching the cooling zone E, the products are cooled by the cooling air from the duct 26, passed through the opening 18, and received by the product discharge device 19. After passing through the product hopper 37 and the discharge damper 38, the products are collected on the rotary table 39. It is taken out to the outside by a delivery conveyor 40.

Therefore, when firing this raw stone, the primary working air from the primary working air blower 21 is preheated by the requilifier 20, and then the primary air is supplied from the header 22 to the upper burner 16 to generate combustion air. Therefore, the working air flows through the same header 2.
2 to the injector 23 to suck in the tertiary air from the duct 26 and the combustion gas flowing back from the lower combustion chamber 7, and then reach the hot air generator 6 through the header 27 where it is combusted. Ru.
Further, the secondary air from the secondary air blower 24 is preheated while passing through the cooling passage 4, and a part of it reaches the header 25 and the upper burner 16, and the other part reaches the hot air generating furnace 6 and is combusted. be done. In addition,
When using solid coke as a fuel, it is sufficient to mix a certain amount of coke into raw stone and feed it from the top of the furnace, and when using pulverized coal, it can be forced into the burner by pneumatic conveyance. .

[Effects of the Invention] As detailed above, according to the present invention, the truncated conical part formed in the cylindrical inner cylinder and the truncated conical part of the cylindrical outer cylinder fitted around the inner cylinder are compatible with each other. The furnace body has a structure in which a plurality of firing zones are formed by combining the bulges formed in the parts, so the cross section in the vertical direction is symmetrical and the cross section in the horizontal direction is circular, resulting in excellent self-supporting stability. The risk of overturning is reduced, the construction of the frame for supporting the furnace body, including partial reinforcement, is simplified, the amount of steel used can be sufficiently reduced, and the number of bricks required per cross-sectional area is also reduced. In addition to reducing production costs and making it possible to increase the size of the product, since there are no flat walls or obstructions, there is no difference in speed or drift in the flow of raw ore and gas. ,
In addition, the combustion chamber is arranged in the space formed by the combination of the truncated conical part and the bulging part and the flow angle of repose of the rough stone, and the inside of the inner cylinder is used for preheating the combustion air. This has various beneficial effects, such as significantly improving combustion efficiency.

[Brief explanation of drawings]

The drawing is a longitudinal sectional view showing an embodiment of a firing furnace according to the present invention. 1... Cylindrical inner tube, 2... truncated conical part, 5...
Hot air flue, 6... Hot air generating furnace, 7... Lower combustion chamber, 8... Exhaust flue, 11... Cylindrical outer cylinder, 12
...Bulging part, 13... Upper combustion chamber, 16... Upper burner, 17... Circulating gas suction port, 18... Take-out opening, 19... Product take-out device, 23...
Injector, 30...Rough stone carrying conveyor, 40...
...Product delivery conveyor.

Claims (1)

[Claims] 1. An inner cylinder having a cylindrical cross section with a truncated conical part protruding in the circumferential direction at the vertically intermediate portion, and a bulging part provided at intervals around the inner cylinder and surrounding the bulge corresponding to the upper part of the truncated cone. A furnace body is constituted by an outer cylinder having a cylindrical cross section that bulges in the direction, and an upper combustion chamber having a burner is formed at the upper part of the bulge, and a lower combustion chamber is formed below the truncated conical part. In addition, a firing furnace characterized in that a flue of the hot air generating furnace is opened from inside the inner cylinder into the lower combustion chamber so that exhaust gas can be taken out from the top of the furnace.