JPS5896678A - Method for controlling grain size and strength of coke - Google Patents

Abstract

PURPOSE:To improve the strength of coke for blast furnace and the yield of the coke block, by controlling the impact applied to the coke blocks during the transport from the coke even to the blast furnace to be equivalent to the impact applied to the coke at a specific number of rotation of a drum tester. CONSTITUTION:The grain size and the strength of coke for blast furnace can be controlled by contrlling the transportation process of the coke from the coke even to the blast furnace so as to make the impact applied to the coke in the transportation equivalent to the impact applied to the coke by the JIS M 8801 drum test at 40-60 revolutions. EFFECT:The expensive and limited resources of coal for coke can be saved. Since the dust generation can be suppressed to the lowest possible level, the process is preferable in view of the prevention of pollution and improvement of the working environment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently transporting blast furnace coke from the front of the coke oven to the front of the blast furnace. On the way, the large lumps are crushed by a cutter and then transported to the front of the blast furnace.

When this coke lump is transferred to another peltco/veyer, it is subjected to impact from falling and also from the cutter, so it is crushed and gradually becomes small agglomerates while generating powder. go. Now, coke used in blast furnaces requires ξ to ensure air permeability of the blast furnace, so coke powder cannot be used, and lump M
- From this point of view, where only the waste is supplied to the blast furnace, the impact force during the transport process can be reduced as much as possible and
It is desirable to improve iI. As a precautionary measure to reduce the impact force, ■reducing the speed of the belt conveyor, and ■increasing the head of the shade, which is a device that transfers coke to another peltco/veyer using its own weight. ■It is well known that it is effective to install a repellent plate midway inside the chute to disperse the impact force.

On the other hand, in order to maintain good air permeability in a blast furnace, it is desirable for coke to have sufficient strength.Brittle coke lumps can easily collapse in the blast furnace, reducing air permeability. It is. From this point of view, the larger the impact force during the transportation process, the better.In other words, the coke lump after firing contains many structural defects such as cracks, but if it is subjected to impact, it will fracture from the defective parts. This is because the number of defective parts is reduced in the mine after crushing, and the strength is improved.

As is clear from the above explanation, when transporting blast furnace coke, it is desirable to adjust the bridge impact force 8 during the transport process in order to improve lump yield and coke strength. Because the effects on yield and coke strength are contradictory, and the coke destruction mechanism is complex, no rational guidelines have been obtained regarding the adjustment of impact force. For this reason, transportation methods were left unaddressed, which sometimes involved pulverizing more coke than necessary, wasting coal resources, or supplying coke that was not strong enough, leading to deterioration of furnace conditions.

In order to investigate the essential relationship between the above-mentioned impact and the fracture behavior of coke, the present inventors conducted the following research on the relationship between the improvement in coke strength due to impact and the amount of powder generated. The book JilfI found that good effects could be obtained by controlling it as described in detail.
I reached A.

Collect 50 to 75 pieces of coke in front of the coke oven, put it in a drum tester specified in JIS M B2O2, take it out after 10 revolutions, and sieve it with a square mesh sieve of 22.31° and 50 m. 50 m (hereinafter referred to as section 1), 50 to 31 m (hereinafter referred to as section 2), 31
The weight of each section from ~22■ (hereinafter referred to as section 3) was recorded. The lump in section 1 is the inner sieve size 50 of the initially charged coke.
Since it was not destroyed under the initial pressure, if the probability of failure due to the impact l of one rotation of the drum is taken as town, then the mass weight of the section l after 10 rotations - (1 - α) 1 @ × [initial input weight] is established, and al can be determined. Next, section 2.
After the particles of No. 3 were colored yellow and green with pigment and dried, they were placed in a drum tester together with the lumps of section 1 and the powder of 22 fine sieve meshes or less, and after 10 more revolutions, the sieving operation was carried out. At this time, section 1. If a lump of λ3 is destroyed by the impact of one rotation of the drum and does not remain in the original section, and the 6iI rate is α2, bird, and γ8, respectively, the weight of the lump in section 1 after rotation - (1 - α) 16X (previous Total weight of section 1] Weight of yellow lump in section 2 after rotation - (1-^)l@x [Total weight of previous section 2] Weight of green lump in section 3 after rotation = (1 -r, )"x (total weight of the previous section 3) is established, and ~, bird, h is found. Again, section 2.3
By coloring the blocks and performing the same operation, it is possible to determine the relationship between the amount of impact received by drum rotation and the probability of failure.

The results thus obtained are shown in FIG. From this figure,
It was found that receiving an impact corresponding to 40 to 60 rotations of the drum is sufficient to improve the strength of coke. To explain in detail, the lump in section l is extremely easy to break if it is not subjected to impact, and the impact If a shock is applied to the drum, it will rapidly break and become separated due to the removal of the defect, but this tendency continues until an impact corresponding to 40 to 60 rotations of the drum is applied, and after that, even if an impact is applied, the probability of breakage decreases. is insignificant and is not very effective in improving coke strength (see the curve marked with ○ in Figure 1).0 Similarly, regarding the lumps in section 2.3 generated by crushing the lumps in section l, An impact corresponding to 40 to 60 rotations of the drum is sufficient to improve the strength (see the curves marked with x and * in Figure 1).

There is a relationship shown in Figure 2 between the ratio of the amount of coke powder produced below -22sa to the initial amount of coke lumps introduced and the drum rotation speed. The amount increases linearly. Therefore, applying more impact to coke than necessary will only lead to a decrease in lump yield, and no significant effect on strength improvement can be expected.

As is clear from the above explanation, the coke particle size/strength management method of the present invention allows the coke lump to be subjected to an impact during 40 to 60 revolutions using a coke drum tester that meets JISM8801. If it is adjusted to be equivalent to =-, it is possible to improve the cous strength and lump yield.

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples. In a large factory, coke lumps with a particle size of 50 to 75 m were collected in front of the coke oven and in front of the blast furnace, and JIS M
Coke strength by 58 ol (DIπ scale measurement obtained values of 92.3 in front of the coke oven and 96.0 in front of the blast furnace. At this time, the yield of coke lumps with a particle size of 22 m or more in front of the blast furnace was The following experiment was conducted to find out the impact that coke received during transportation.In other words, coke of all particle sizes was sampled in front of a coke oven and placed in a drum tester. Give rotation of foot, 5 after rotation
Take out a lump of coke with a scale of 0 to 75 and conduct JI on it.
DI, by S M 8801.

was measured, and the relationship between the processing rotation speed and DIπ was investigated, and the results shown in FIG. 3 were obtained. If we apply the value of DID: in front of the blast furnace to Figure 3, it is known that during the transportation process the drum receives a shock equivalent to 70 revolutions, which means that the shock is more than necessary. When a baffle plate was installed in the chute to disperse the impact force, the DI of coke in front of the blast furnace was 95.7.
According to the relationship shown in FIG. 3, the impact was reduced to 55 rotations of the drum, which was within the appropriate impact force range according to the present invention. As a result, the yield of lumps with a grain size of 22 or less before the blast furnace was 0.
It improved to 9 and became 84.7%. In addition, when these lump cokes are used, the blast furnace can be operated at 1I without any problems.
As is clear from the fins of 0 or more that have changed to AI1, the method for controlling coke particle size and strength of the present invention brings about the following advantages.

(1) Since the coke lump yield is not reduced more than necessary, it is possible to save coking coal resources, which are expensive and have little reserves, which is a raw material for coke.

(2) It does not generate more dust than necessary, which is preferable in terms of pollution prevention and working environment.

■ There is no need to supply coke lumps with insufficient strength.
Contributing to the smooth operation of blast furnacesT6゜

[Brief explanation of drawings]

#! Figure 1 shows the relationship between the drum rotation speed of the drum tester and the probability of coke lump failure according to JIS M 8801, and Figure 2 shows the relationship between the drum rotation speed of the drum tester and the powder ratio with a particle size of 22- or less. FIG. 3 is a graph showing the relationship between the number of revolutions processed by the drum tester and DI-. Patent Applicant Kawasaki Steel Co., Ltd. Agent Patent Attorney Nozomi Watanabe Minoruatsu Figure 1 V-ram surround

Claims (1)

[Claims] When transporting coke for blast furnaces from the front of the coke oven to the front of the blast furnace, the impact that the coke receives during the transport process is %J.
A method for controlling the particle size and strength of coke, characterized by controlling the coke transport process so that the impact and force exerted by a coke drum tester specified in ISM 8801 at 40 to 60 revolutions is the same.