JP2641054B2 - Hard type firing furnace - Google Patents

Description

The present invention relates to a solid firing furnace for firing limestone, dolomite, magnesite and other similar ores.

[Conventional technology]

In order to fire the ore, the ore and solid fuel, such as coke and coal, are mixed and put into a solid firing furnace, where a pre-tropical zone, a firing zone, and a cooling zone are sequentially formed from the top in the furnace. After firing, the ore is taken out from the outlet at the bottom of the furnace after cooling. To perform firing sufficiently,
Sufficient air for combustion must be supplied to the solid fuel that glows red in the firing zone. However, in order to increase the size of the apparatus and reduce the power of the blower, the amount of the air is usually set to a minimum. However, the filling density of the ore and the solid fuel in the furnace wall portion in the furnace tends to be low due to the gap generated between the ore and the inner wall surface. In such a case, even if the combustion air is supplied from the lower part of the furnace, that is, the cooling zone, a large amount of air is supplied to the furnace wall having a low packing density (high porosity) due to low resistance to the air flow. Flows. That is, a situation occurs in the core where there is a shortage of air for combustion.

Originally, solid fuel is gasified as C + 1 / 2O ₂ → CO, and if there is sufficient air, the above-mentioned CO undergoes a combustion reaction of CO + 1 / 2O ₂ → CO ₂ . However, as described above, if there is a shortage of air in the core, the reaction ends up with the reaction up to CO, which is discharged outside the furnace as exhaust gas, and energy is lost as fuel.

[Problems to be solved by the invention]

As a solution to the above problem, artificial stones and solid fuel of small diameter are placed on the furnace wall, and those of large diameter are placed on the core so that almost the same porosity is obtained between the furnace wall and the core. Although loading is performed, such an operation is extremely complicated, takes a long time, and does not provide a completely uniform air flow. Furthermore, even if the airflow is averaged within the allowable value, CO may still remain due to the flow rate itself.

The present invention is to solve the above drawbacks, by supplying air of a minimum required limit, yet almost without leaving the CO, and to provide a completely burned by Ken type firing furnace which makes it possible to exhaust turned into CO ₂ The purpose is.

[Means for solving the problem]

According to the present invention, the object is to provide, at the upper part of a rigid furnace, a charging means for charging an ore to be fired into the furnace and an exhaust means for discharging exhaust gas from the furnace to the outside of the furnace. Wherein the rough ore formed a pre-tropical zone, a sintering zone and a cooling zone from the upper zone in the furnace, and provided with air supply means for supplying combustion air into the zone of the cooling zone located at the lower part of the furnace. A space above the upper surface of the pre-tropical zone is provided with a control pipe for blowing a suppressive gas for suppressing the rise of the rising gas from the upper surface of the pre-tropical zone to the upper surface of the pre-tropical zone. .

[Action]

According to the present invention, the gas is blown from the control pipe to the upper surface of the pre-tropical zone, which is the upper layer of the rough, and the pressure thereof causes
Since the rising gas which is going to escape from the pre-tropical zone is suppressed, the rising gas reaches the entire pre-tropical zone and the calcination zone sufficiently and is completely subjected to the CO ₂ reaction because of the high temperature. Burned.

〔Example〕

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

FIG. 1 is a longitudinal sectional view of the apparatus of the present embodiment, and 1 is a rigid furnace main body in which bricks are fixed with steel plates. The furnace main body 1 has a cylindrical shape over substantially the entirety, and has a shape of a convergent portion with a lower portion facing downward.

In the center part of the furnace lid 2 of the furnace body 1, as a means for charging a mixture of ore and solid fuel, a charging member connected to a tube extending obliquely and swinging and rotating to the lower part of a cylindrical body opening upward. 3 are provided. The charging member 3 is driven by a motor 5 via a gear 4 to rotate around the axis 6 when the mixture is charged, and the mixture S is deposited on the furnace body 1 on average. .

An air inlet 9 for combustion is provided through a pipe 8 from a blower 7 disposed outside the furnace, at a central position of the lower conical portion at the lower portion of the furnace body 1. An opening at the lower end of the furnace body 1 is an outlet of the product after firing the raw stone, and the product can be sequentially dropped and taken out by the rotary valve 11.

An exhaust pipe 12 for discharging exhaust gas to the outside of the furnace is connected to an upper space of the furnace body 1. A control tube 14 is supported on the furnace lid 2 at a plurality of positions in the circumferential direction, for example, at three positions by a spherical bearing 13 so as to swing freely and to slide in the longitudinal direction.
Is provided. The control tube 14 has an open lower end that expands in a truncated shape and an upper end connected to a flexible tube 15. Control tube 14
Can be moved up and down by hoisting the chain 17 of the hoisting device 16. On the other hand, a branch pipe 18 is connected to the exhaust pipe 12 and extended through a blower 19, and the flexible pipe 15 is connected to the branch pipe 18. Thus, the exhaust gas returns to the furnace body 1 again. I can do it. Further, an adjustment valve 20 for controlling the flow rate of the return exhaust gas is provided in such a pipeline.

According to the apparatus of this embodiment, when the solid fuel is burned, the mixture S of the rough and the solid fuel supplied from the charging member 3 becomes pre-tropical A, firing zone B, and cooling zone C in the furnace main body 1 from above. Is formed. That is, the fuel is burned in the sintering zone B by the air sent from the air inlet 9 through the pipe 8 by the blower 7, and the ore is baked by the heat. The fuel gas rises between the mixture particles and passes through the pre-tropical zone A, whereupon the fuel gas preheats the mixture prior to firing and promotes firing in the firing zone B. The ore fired in this manner descends sequentially as the product is taken out from the rotary valve 19, reaches the cooling zone C, where it is cooled by the air from the air inlet 9, and is taken out as a product as described above.

In the apparatus of this embodiment, the ore is fired as described above to become a product, but in this embodiment, the solid fuel is completely burned by minimizing the amount of supplied air. That is,
The state of the exhaust gas is checked, for example, for at least one of each concentration value or temperature of CO, O ₂ , and N _{2. If} these values are larger than predetermined values, C + 1 / 2O ₂ → CO CO + 1 / 2O ₂ → CO without complete combustion of CO ₂ is made, O ₂ further determines that N ₂ is said to be abundant in the exhaust gas, also determined that even incomplete combustion the temperature did not warm up to the predetermined value because The exhaust gas containing a lot of CO is controlled by the blower 19 to the control pipe 14
It is something that blows out from. As a result, first, the heat of the exhaust gas is transmitted to the upper surface of the pre-tropical area A, so that the energy can be effectively used.
Suppresses the rising gas from flowing out from the upper surface of the
As for the pre-tropical zone A, the combustion gas in the sintering zone B diffuses inside and stays there for a long time, and the combustion of CO + 1 / 2O ₂ → CO ₂ is completely performed.

In the present embodiment, as the most effective example, the exhaust gas is used as the gas for suppressing the rising gas. However, the control tube may be connected to another blower so as to take in air from outside the furnace.

In the present embodiment, the exhaust of the exhaust gas from the control pipe is performed from control pipes provided at a plurality of locations on the furnace lid, and the control pipe swings, so that the control pipe reaches the upper surface of the pre-tropical zone.

Further, the return of the exhaust gas can be automated.

First, if each concentration value of CO, O ₂ , N ₂ and a temperature sensor (not shown) are attached to the outer periphery of the control pipe, the pre-tropical A
The situation of the rising gas flowing out to the upper surface of the sensor can be detected, whereby it is possible to grasp whether or not the fuel is completely burned according to the principle of the prior art. It can be opened and closed with an opening proportional to the value.

In addition, if the above sensors are arranged at a plurality of locations in the furnace,
The control value can be directed to the required value by the detected value.

〔The invention's effect〕

As described above, the present invention determines the fuel state of the solid fuel from the state of the exhaust gas, and sprays the exhaust gas or air onto the pretropical upper surface as necessary to suppress rising gas and reduce the combustion gas in the pretropical or Since it is diffused in the sintering zone and kept for a long period of time, complete combustion is ensured with the required minimum amount of supplied air, and the apparatus can be miniaturized to reduce power. In other words, when there is a restriction on the amount of supplied air, it is possible to obtain an effect that sufficient sintering is performed even under the air amount and the quality of the product can be ensured.

[Brief description of the drawings]

 FIG. 1 is a longitudinal sectional view showing an apparatus according to an embodiment of the present invention. 1 Furnace (furnace main body) 3 Charging means (charging member) 9 Air supply means (air inlet) 12 Exhaust means (exhaust pipe) 14 Control pipe A Pre-tropical B Firing zone C: Cooling zone

Claims (6)

(57) [Claims] 1. An upper part of a hard furnace having a charging means for charging a raw stone to be fired into the furnace and an exhaust means for discharging exhaust gas from the furnace to the outside of the furnace. Forming a pre-tropical zone, firing zone and cooling zone from the upper zone within
An air supply means for supplying air for combustion into a zone of the cooling zone located at a lower part of the furnace, wherein a space above the upper surface of the pre-tropical zone has a rising gas rising from the upper surface of the pre-tropical zone. A control tube for blowing a suppressing gas for suppressing the above to the upper surface of the pre-tropical zone. 2. The solid firing furnace according to claim 1, wherein the control pipe is opened outside the furnace through a blower so as to take in air outside the furnace as a suppression gas. 3. The solid firing furnace according to claim 1, wherein the control pipe is connected to exhaust means via a blower so as to take in exhaust gas. 4. The solid firing furnace according to claim 1, wherein the position of the outlet of the control pipe in the horizontal direction is variable. . 5. The control pipe has a valve with a variable opening, and has a CO concentration value, an O ₂ concentration value, a N ₂
A sensor for detecting at least one of a concentration value and a temperature, wherein the valve opens intermittently or proportionally when a value detected by the sensor is lower than a predetermined value. Or one of claims (4)
The solid-type firing furnace according to any one of the first to third aspects. 6. A sensor for detecting at least one of a CO concentration value, an O ₂ concentration value, an N ₂ concentration value and a temperature of a rising gas in a space above the upper surface of the pre-tropical zone at a plurality of horizontal positions. And the control pipe is arranged such that the outlet moves or directs toward a region in which the value detected by the sensor is lower than a predetermined value. 5) A solid-type firing furnace according to one of 5).