JPH07278686A - Operation method of waste gas circulating and sintering machine - Google Patents

Abstract

PURPOSE:To decrease the amt. of cake per unit quantity of pseudo particles and improve the yield of products by incorporating a specific amt. of water into raw materials to be sintered to intensify pelletization in a bedding ore stage, then adhering powder coke to the particle surfaces and forming the raw materials into the pseudo particles. CONSTITUTION:The water is sprayed and included on and into the surfaces of the raw materials F to be sintered in such a manner that the bedding ore moisture content attains 7.0 to 10.0%, more preferably 8.5 to 10.0% in the bedding ore stage prior to mixing the powder coke C into the raw materials F to be sintered. The powder coke C is adhered to the particle surfaces of the raw materials F to be sintered previously reinforced in pelletization in such a manner and thereafter, the raw materials are formed into the pseudo particles and are charged into a sintering bed. As a result, the segregation stabilized in the amt. of cake over the entire part of the raw material layer is realized and the air permeability is improved. The good product strength is thus obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an exhaust gas circulation sintering machine, and more specifically, it is possible to prevent powder coke from being mixed into pseudo-granulated raw material particles, and thereby to prevent pseudo-particles from being mixed. The present invention relates to an operating method of an exhaust gas circulation sintering machine that can reduce the amount of coke per unit weight, improve the product yield, and achieve stable segregation of the amount of coke over the entire raw material layer.

[0002]

2. Description of the Related Art As a kind of operation method for continuously sintering a sintering raw material, air is sucked below the sintering bed while moving a large number of the sintering beds in a sinter machine. Known are a Dwightroid method of sintering and an exhaust gas circulation sintering method of returning exhaust gas discharged from a sintering machine to the sintering bed again to reuse it as a heat source for sintering the sintering raw material.

In each operating method, a sintering raw material containing coke is charged on a sintering bed from a charging hopper, and then an upper portion of the raw material layer is ignited in an ignition furnace of a sintering machine to set a heat retaining furnace. During the passage, the hot red tropical zone of about 1100 degrees gradually descends to the lower layer, and the combustion ends by the time it is discharged from the sintering machine. The ideal sintering (appropriate sintering) by the Dwightroid system is shown by the broken line in the graph of FIG.

By the way, in the exhaust gas circulation system, since high-temperature exhaust gas is sucked into the raw material layer from above the bed, preheating of the sintering raw material after passing through the red tropical zone becomes excessive as compared with the Dwightroid system in which air is sucked. The lower the raw material layer, the thicker the red tropical zone where the pressure loss is large (see the solid line in Fig. 6). As a result, the air permeability deteriorates, and the sintering temperature increases from the upper layer to the lower layer, which causes variations in the strength of the sintered ore, which is a major determinant of the temperature, and the product yield decreases.

Therefore, in order to solve these problems, the amount of coke blended with the sintering raw material as described in, for example, "Sintering Method of Iron Ore" in Japanese Patent Laid-Open No. 53-125904. It is known that the heat balance is increased toward the upper layer side of the raw material layer so that an appropriate heat balance can be obtained over the entire layer on the sintering bed.
This method is to make the sintering temperature of the raw material layer as uniform as possible by producing an appropriate heat balance, produce a sinter having a stable strength, and improve the product yield.

By the way, as a method of increasing the amount of coke toward the upper layer side of the raw material layer in this way, for example, as shown in FIG.
A method of using a sizing / dispersion type charging device (manual number 1-66599) having a large number of bear-shaped bars shown in FIG. As shown in FIG. 7, a sizing / dispersion charging device 10
In the case of 0, the pseudo-granulated sintering raw material F having a large grain size dropped from the wide tip between the bars 102 onto the empty sintering bed 101 being moved, and thereafter, the sintering grain size gradually decreased. The raw material F drops from the central portion and the vicinity of the base portion of the bar 102, and finally the sintering raw material F having the smallest grain size drops from the end of the base portion of the bar 102.

As shown in FIG. 8, powdery coke C is adhered to the surface of the particles of the sintering raw material F in the granulation process, and generally the particle size of the sintering raw material F becomes small and per unit volume. The larger the surface area of, the greater the total amount of coke. Therefore, this sizing / dispersion charging device 100
When the raw material is charged into the sintering bed 101, the amount of coke in the upper layer of the raw material layer on which the fine sintering raw material F is laminated is larger than that in the lower layer.

However, in the usual granulation method, the sintering raw material F is added in the mixer while adding a predetermined amount of water.
Since the powdery coke C and the powdery coke C are agitated and pseudo-granulated, the powdery coke C is wrapped in the particles of the sintering raw material F. Powdery coke C mixed in the sintering raw material F
Unlike the powdery coke C on the surface of the particles which is directly exposed to the flame at the time of sintering the raw material, it hardly increases the use amount of the powdery coke C and decreases the product yield regardless of the combustion.

Therefore, as a means for solving this, the applicant of the present application has developed the "pretreatment method for sintering raw material" in Japanese Patent Laid-Open No. 54809/54 prior to the present application.
In this method, the powdery coke C is impregnated with a predetermined amount of water in advance, and the coke C is mixed with the sintering raw material F and pseudo-granulated while adding less water than the usual addition amount. By this, raw material particles having a large proportion of the powdery coke C attached to the particle surfaces are obtained.

[0010]

However, in this conventional method, the adhering ratio of the powdery coke C to the surface of the particles is certainly increased, but on the other hand, due to the water added in advance, a part of the powdery coke C is added. Although it causes pseudo-granulation between Cs, and although the amount is not the same as before, some powdery coke C is wrapped in the raw material particles and the set amount of powdery coke C is mixed. However, there is a problem in that the segregation of the coke amount over the entire raw material layer varies because the coke amount is increased toward the upper layer side, and stable segregation of the coke amount cannot be performed.

The present invention has been made in view of such circumstances, and it is possible to prevent mixing of powdery coke into the pseudo-granulated raw material particles, thereby reducing the amount of coke per unit weight of the pseudo-particle and improving the product quality. An object of the present invention is to provide an operating method of an exhaust gas circulation sintering machine capable of improving yield and realizing stable segregation of coke amount over the entire raw material layer.

[0012]

A method according to the above-mentioned object.
The operating method of the exhaust gas circulation sintering machine described is a soaking step before mixing powdery coke into a sintering raw material, and the soaking raw material has a water content in the range of 7.0 to 10.0%. Is preliminarily granulated and strengthened, then the powdery coke is attached to the surface of the particles, and then the pseudo-granulated sintering raw material is charged into a sintering bed.

According to a second aspect of the present invention, there is provided an operating method of an exhaust gas circulating and sintering machine according to the first aspect of the present invention, which is the operating method of an exhaust gas circulating and sintering machine according to the first aspect. Depending on the amount, the amount of coke in the raw material layer,
It is configured so as to increase in a gradient composition toward the upper layer side of the raw material layer.

[0014]

In the operating method of the exhaust gas circulation sintering machine according to claims 1 and 2, the sintering raw material has a moisture content of 7.0 to 7.0 in the soaking step.
Since the powdery coke is attached to the surface of the particles after the granulation is strengthened in advance by adding water in the range of 10.0%, there is little possibility that the powdery coke is wrapped in the raw material particles,
Dry powdery coke adheres to the surface of the granulated and strengthened raw material particles, whereby the amount of coke per unit weight of the pseudo particles can be reduced and the product yield can be improved.

Particularly, in the operating method of the exhaust gas circulation sintering machine according to the second aspect, the coke amount in the raw material layer is changed according to the exhaust gas circulation location and the circulation amount of the sintering machine for performing the exhaust gas circulation sintering. Increasing the composition gradually toward the upper side of the bed, so that a suitable heat balance can be obtained over the entire bed on the sintering bed in accordance with the sintering of various exhaust gas circulations. It is possible to achieve thinning, improvement of breathability, stabilization of good product strength, and improvement of product yield. Moreover, since the sintering raw material is made to contain water in the soaking process to strengthen the granulation beforehand and the powdery coke is adhered to the particle surface, the powdery coke wrapped in the raw material particles is almost eliminated, and it is preset. The amount of powdered coke added is almost the amount actually added to the surface of the raw material particles,
This makes it possible to eliminate the variation in the segregation of the amount of coke over the entire raw material layer.

[0016]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is a schematic configuration diagram of an exhaust gas circulation type sintering machine for an exhaust ore section according to an embodiment of the present invention, and FIG. 2 is a schematic configuration of an exhaust gas circulation type sintering machine for an ore supply section. Fig. 3 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to the supply and discharge mining section, Fig. 4
Is a graph showing the relationship of coke segregation suitable for in-layer, and FIG. 5 is an enlarged plan view of raw material particles showing a granulation step.

An operating method of an exhaust gas circulation sintering machine according to one embodiment of the present invention is an exhaust gas circulation firing system in which exhaust gas discharged from a sintering machine through a main duct is returned to a sintering bed by a blower and reused. It is the operating method at the conclusion. Figures 1-3
In the exhaust gas circulation sintering machine 10 (10A to 10C) adopting this method, the exhaust gas circulation system to the ore discharge section 12 (see FIG. 1) is different depending on the location where the exhaust gas 11 is circulated. Exhaust gas circulation method to the mining section 13 (see FIG. 2) and exhaust gas circulation method to the mining and discharging sections 12, 13 (see FIG. 3)
There are two types.

In each type, sintering raw material mixed with coke is charged into the sintering bed 14 from a charging hopper 15 and ignited above the raw material layer 16 in the ignition furnace of the sintering machine 10. The hot red tropical zone 17 gradually descends to the lower layer while sucking the exhaust gas 11 while passing through the heat retention furnace, and the combustion is completed by the time it is discharged from the sintering machine 10. After that, the sintered ore of the produced sintered layer 18 is crushed by the primary crusher,
Cooled in cooler.

Now, as shown in FIG. 5, the characteristic feature of the operating method of the exhaust gas circulation sintering machine of the present invention is that the sintering raw material F is obtained in the soaking step before the powdery coke C is mixed with the sintering raw material F. This is the point that the powder is coagulated beforehand with water to strengthen the granulation, and then the powdery coke C is attached to the surface of the particle, and then the pseudo-granulated sintering raw material F is charged into the sintering bed 14. The soaking process is a process in which sintering raw materials F (iron ore) of different brands stored in a plurality of relay tanks are blended and piled up in a pile called soaking.

Before being piled up in the soaking ore, the surface of the sintering raw material F is sprinkled with soaking water of 7.0 to 10.0%, particularly 8.5 to 10.0%. . If the soaking water content is less than 7.0%, the pseudo-granulation strength becomes equal to that of the conventional one, and the effect of the present invention is not obtained. If it exceeds 10.0%,
Excessive water content causes deterioration of ventilation of the sintering bed. In addition, it causes landslides during handling, which makes work difficult. For example, when the uniform water content is 8.5%, (+0.25 mm% after drying) / (+ 0.25 mm% after watering) ×
The pseudo-granulation index GI ₂ obtained by the equation of 100 is 9
It was as high as 0%.

Even in the conventional method, the moisture content of the sintering raw material F piled up in the soaking ore is as small as about 6.5% and the pseudo-granulation index GI ₂ is as small as about 83%. . After that, the sintering raw material F is cut out from the uniform ore and once stored in the coke storage part of the storage tank, and then sent to the granulation step together with the powdery coke C stored in the coke storage part of the storage tank, Here, it is pseudo-granulated by a mixer and granulated. Sintering raw material F granulated in this way
Are then sent to the sintering machine 10.

As described above, since the sintering raw material F is made to contain a predetermined water content in the soaking step to be granulated and strengthened in advance, the powdery coke C is adhered to the surface of the particles, so that The powdery coke C is less likely to be wrapped, and the dry powdery coke C is formed on the surface of the granulation-reinforced raw material particles.
By adhering, the amount of coke per unit weight of the pseudo particles can be reduced and the product yield can be improved.

Further, in the present embodiment, the coke amount in the upper layer of the raw material layer 16 is increased from that in the lower layer in a graded composition according to the exhaust gas circulation location and circulation amount of the sintering machine 10. As a result, an appropriate heat balance can be obtained over the entire layer on the sintering bed 14 in accordance with the sintering of various exhaust gas circulations without forming a fault of the grain size, and the lower red tropical zone 17a having a continuously optimum thickness can be obtained. Therefore, the breathability is improved, and good product strength is stabilized, and the product yield is improved. Moreover, as described above, since the sintering raw material F is made to contain water in the soaking step to be granulated and strengthened in advance, the powdery coke C is adhered to the particle surface,
Many of the sintering raw materials F charged in the mixer become pseudo particles having a relatively large bond strength centered on the core particles. Therefore, the powdery coke C that is enclosed in the raw material particles is almost eliminated, and the preset addition amount of the powdery coke C is almost the actual amount added to the surface of the raw material particles.
Thereby, the variation in the segregation of the coke amount over the entire raw material layer is reduced, and the coke amount can be stabilized.

As a means for increasing the amount of coke in the upper layer of the raw material layer 16 from the lower layer in a gradient compounding manner, for example, the sizing / dispersing type charging device shown in FIG. In addition, when adjusting the segregation index of the amount of coke in the upper and lower layers of the raw material layer 16, a simple operation of widening or narrowing the interval between the bars may be performed.

Next, referring to Table 1, sintering examples (cases 2, 4 and 6) according to the operating method of the exhaust gas circulation sintering machine according to one embodiment of the present invention, and the conventional exhaust gas circulation sintering machine will be described. The sintering examples (cases 1, 3, 5) according to the operating method will be specifically described in comparison. In addition, the base in Table 1 shows an appropriate sintering operation of the Dwightroid system which is an adjustment target, in the same table to show the four segregation patterns of the in-layer coke in FIG. 4, and ΔC is the raw material layer 16 The segregation index of the amount of coke in the upper layer and the lower layer is shown.

[0026]

[Table 1]

As is clear from Table 1, in the soaking step before the powdery coke C is mixed with the sintering raw material F, the sintering raw material F is sprinkled with water so as to have a predetermined soaking water content and granulated in advance. Strengthen,
Then, it was sent to the granulation step so that the powdery coke C was adhered to the surface of the particles, so that the encapsulation of the powdery coke C in the raw material particles was reduced, and the coke amount per unit weight of the pseudo particles was 0. The product yield could be improved by 0.8 to 2.9% while the product yield was reduced by 0.7 to 3.4 kg / t. Moreover, since the coke amounts of the upper layer and the lower layer of the raw material layer 16 are increased in a gradient composition toward the upper layer side of the raw material layer 16 according to the exhaust gas circulation location and the circulation amount of the sintering machine 10, the productivity, Since the product yield, air permeability, cold strength, etc. approached or exceeded the numerical values of the base during proper operation, it was possible to improve operation and improve powder coke and recovered steam.

[0028]

In the operating method of the exhaust gas circulating sintering machine according to the first aspect of the present invention, in the soaking step before the powdery coke is mixed with the sintering raw material, a predetermined soaking water content is added to the sintering raw material. Since it was sprinkled with water to strengthen the granulation in advance and then sent to the granulation step to attach the powdery coke to the particle surface, the encapsulation of the powdery coke in the raw material particles was reduced, which resulted in pseudo particles. The amount of coke per unit weight can be reduced and the product yield can be improved.

Particularly, in the operating method of the exhaust gas circulation sintering machine according to the second aspect, the coke amount in the entire raw material layer is directed toward the upper layer side of the raw material layer according to the exhaust gas circulation location and the circulation amount of the sintering machine. Since the gradient is increased in a gradient manner, a proper thermal balance can be obtained over the layers on the sintering bed without forming a grain size fault, and a lower red tropical zone with an optimum thickness can be continuously obtained. This improves breathability, stabilizes good product strength, and improves product yield.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to an exhaust ore section according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an exhaust gas circulating type sintering machine to the ore feeding section.

FIG. 3 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to the same feeding and discharging section.

FIG. 4 is a graph showing the relationship of coke segregation suitable for in-layer coke.

FIG. 5 is an enlarged plan view of raw material particles showing a granulation step.

FIG. 6 is a graph showing a 1000 ° C. holding time in the inner part of the layer.

FIG. 7 is an enlarged side view of an essential part showing a usage state of the particle size regulating / dispersion charging device.

FIG. 8 is an enlarged plan view of raw material particles granulated by conventional means.

[Explanation of symbols]

 10 Exhaust Gas Recirculation Sintering Machine 10A Exhaust Gas Recirculation Sintering Machine 10B Exhaust Gas Recirculation Sintering Machine 10C Exhaust Gas Recirculation Sintering Machine 11 Exhaust Gas 12 Exhaust Ore Part 13 Mining Part 14 Sintering Bed 15 Charging Hopper 16 Raw Material Layer 17 Red Tropical Zone 17a Lower Layer Red tropical 18 Sintered layer

Claims (2)

[Claims] 1. A soaking ore moisture of 7.0 to 10.0 in the sintering raw material in a soaking step before mixing powdery coke into the sintering raw material.
% Of water is included for granulation strengthening in advance, then the powdery coke is adhered to the surface of the particles, and then the pseudo-granulated sintering raw material is charged into a sintering bed. Exhaust gas circulation sintering machine operating method. 2. The amount of coke in the raw material layer is gradually increased toward the upper layer side of the raw material layer in a compounding manner in accordance with the exhaust gas circulation location and the circulation amount of a sintering machine that performs exhaust gas circulation sintering. The method for operating an exhaust gas circulation sintering machine according to claim 1, wherein: