JPH06313171A - Production of high-reactivity coke - Google Patents

Abstract

PURPOSE:To produce, in chamber oven, a high-reactivity coke (with a CRI of 50 or higher and a DI<150>15 5 of 70 or higher) which is mixed with a sintered ore and charged into a blast furnace to improve the reduction efficiency in the oven. CONSTITUTION:The reactivity and strengths of coke are adjusted by compounding a coking coal with 10-30wt.% inert substance having a low volatile content and contg. 70-100wt.% particles of which at least 90wt.% have particle sizes of 0.3mm or lower and by adjusting the weighted mean of volatile contents and weighted means of the max. flowability of the coking coal by using the equations: Y=a+bX(VM)+cX(VM)<2> and Z=d+eX(VM)+fX(MF)+ gX(VM)X(MF) [wherein Y is coke reactivity (CRIB) Z is coke strengths (DI<15015>); (VM) is the weighted mean of volatile components of coal; (MF) is the weighted mean of the max. flowability of coal (log DDPM) and lower than 2.40; and (a) to (g) are each a constant].

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly reactive coke. Specifically 10 to 25 mm
CR used to improve the reduction efficiency in the blast furnace by finely granulating it and mixing it into the sinter and charging it into the blast furnace.
I is 45 or more, preferably 50 or more, and DI ¹⁵⁰ ₁₅ 70
It is intended to provide a method for producing a highly reactive coke, which has the above-mentioned strength and is resistant to kiln removal.

[0002]

2. Description of the Related Art Coke is charged into a vertical reactor as a heat source, as a reducing material, as a pore material, to perform a function of supporting a charge, and the like, and the following description is for convenience sake. Will be described as an example.

In the iron and steel industry based on the integrated structure of pig steel, many measures for reducing the manufacturing cost are adopted. In particular, since the blast furnace operation has a large amount of production and has various functions, if the manufacturing cost can be reduced, the manufacturing cost structure of the lower process can be significantly improved. For example, if the blast furnace can be operated at some lower operating temperature, the main raw material, secondary auxiliary material, tuyere-blown fuel, blast furnace gas generation state, furnace maintenance, furnace life, and other related processes. Because it will improve various technologies, manufacturing costs, etc.
It has a remarkable effect on an unparalleled industrial scale. The idea of lowering the operating temperature is, for example, to lower the temperature of the heat preservation region close to Wustite-iron reduction equilibrium to improve the reduction efficiency in the blast furnace, and the solution is to use a highly reactive coke. It is to start the reaction from the low temperature part. For example, there is the following report. -CAMP-ISIJ Vol. 4 (1991) -10
36 "Technology for Improving Reduction Efficiency in Blast Furnace by Using Highly Reactive Coke" Nippon Steel Corporation ・ CAMP-ISIJ Vol. 5 (1992) -15
6 "Reactive efficiency improvement mechanism when using highly reactive coke" Nippon Steel Corporation ・ CAMP-ISIJ Vol. 5 (1992) -10
65 "Effects of using highly reactive coke under various blast furnace operating conditions" Nippon Steel Corporation

However, the production of high-reactivity coke on an industrial scale means that the higher the strength and the higher reactivity of the coke, the more
For example, it is difficult to manufacture without hindering the manufacturing cost and the life of the coke oven body, and as far as the inventors of the present invention understand, the prior art examples cited below are proposed, for example.・ JP-A-2-127495 "Bulk coke production method"
(Hereinafter, referred to as Reference Example 1.) JP-A-59-179584 "Method for producing highly reactive coke" (hereinafter referred to as Reference Example 2) -JP-A-62-230884 "High reaction" Method for producing sex coke "(hereinafter referred to as Reference Example 3)

That is, there is a reference 1 as a coke manufacturing technique using a caking coal, an inert material and a caking material. The cited example 1 relates to a method for producing a lump coke having an arbitrary particle size and strength by focusing on the property difference of an inert carbonaceous substance and controlling the type and blending ratio of this substance. The total blending amount of low volatile inert carbonaceous material and medium volatile inert carbonaceous material to charcoal or coking coal and pitch is 5 to 50% of all raw materials, and low content of medium volatile inert carbonaceous material and By adjusting the blending ratio with the volatile inert carbonaceous substance within the range of 0.5 to 5 and mixing and dry-distilling, a massive coke having a high drop strength (SI) and a high rupture strength (DI) is produced. It shows what you can do. However, the use of a large amount of the medium volatile inert carbonaceous material in Reference Example 1 aims to increase the size of the lump while maintaining the strength of the coke, and the effect of increasing the reactivity is small. There is.

Further, as a method of increasing the reactivity of coke, a method of adding an alkali metal, an alkaline earth metal or the like to coking coal, or a method of adding a large amount of inferior coal is cited 2
There is. In the reference example 2, a blended coal composed of caking coal and poor quality coal is mixed with 80% to 100% of poor quality coal, 20% to 0% of caking coal, and a forming coal composed of a binder, and the mixture is subjected to dry distillation in a chamber furnace. Suggest that a coke having a JIS reactivity of 35 to 40% can be produced. However, the second reference is
A large amount of steam is required for heating and kneading, which increases the manufacturing cost, and there is an environmental problem because the tar and pitch are evaporated by heating.

[0007] In addition, mixed coal consisting of caking coal and inferior coal is composed of inferior coal as a main component, quick lime as a hardening agent, and waste sugar dense as a caking agent, and kneaded and pressure-molded coal is mixed. The JIS reactivity becomes 5 by dry distillation in a furnace.
There is also a reference 3 which suggests that 0 or more coke can be produced. However, in Reference Example 3, since an alcal metal or an alcal earth metal is added, there is a problem that the coke oven is damaged.

In view of the deceptive background, the inventors of the present invention have a technical object to provide a method for producing a highly reactive coke capable of exerting a remarkable effect distinguishable from the prior art examples which can be grasped up to now. To do. Specifically, the CRI used for improving the reduction efficiency in the blast furnace is 45 or more, preferably 50 or more, by finely pulverizing it to about 10 to 25 mm, mixing it into a sinter, and charging it into a blast furnace. It is intended to provide a method for producing a highly reactive coke having a strength of DI ¹⁵⁰ ₁₅ 70 or higher and capable of withstanding even kiln removal. Further, by using a highly reactive coke having the strength obtained by the production method, by achieving a low temperature reduction of the blast furnace operation, the production cost in the blast furnace, the production cost in the lower step after the blast furnace, etc. It is also a technical issue to improve the manufacturing cost in the so-called pig iron integrated process.
Furthermore, by using the high-strength, highly-reactive coke according to the present invention, high reactivity is exhibited at low temperature, and eventually CO
_{2 A} technical issue is to contribute to the suppression of global warming by suppressing the generation of gas.

The present invention is based on a technical idea that can be distinguished from the prior art examples that can be grasped so far so as to satisfy the deceptive technical problem. In other words, in the present invention, in order to produce a highly reactive coke at a material cost equivalent to that of an ordinary blast furnace coke, that is, a medium volatile inert carbonaceous material and a low volatile inert carbonaceous material are blended. The ratio is in the range of 0 to 0.5. In addition, the manufacturing cost is increased by heating and kneading using a large amount of steam found in the molding coal mixing method, which is produced by a normal chamber furnace method, and tar and pitch are evaporated to cause environmental problems. Try not to. Furthermore, in order to prevent damage to the chamber furnace, it is a technical idea to add only organic substances and carbon substances to the coal to be added, and there are technical problems not found in the above-mentioned prior art examples grasped so far. , To achieve the effect.

The present invention is based on deceptive technical problems and ideas, and has the following features.

[First feature] Inert substances with low volatile content and particle size of 0.3 mm or less of 90% by weight or more
An inactive material occupying 0 to 100% by weight is added to the raw coal 10 to 10.
Blended at a constant blending ratio in the range of 30% by weight, and as a coal property, the weighted average value of the volatile matter of the coal portion and the maximum fluidity (l
The method for producing a highly reactive coke, which comprises controlling the reactivity and strength of the coke by preparing a weighted average value of (ogDDPM) using the following formula. Y = a + b × (VM) + c × (VM) ² (where (MF) <2.40) Z = d + e × (VM) + f × (MF) + g × (VM) × (MF) ─where Y : Coke reactivity (CRI) Z: Coke strength (DI ¹⁵⁰ ₁₅ ) (VM): Weighted average value of volatile matter in coal portion (MF): Weighted average value of maximum fluidity (log DDPM) in coal portion a, b, c, d, e, f, g: constant

[Second feature] The method for producing a highly reactive coke according to the first feature, characterized in that the binder is blended at a constant blending ratio of 10% by weight or less containing 0.

[Third feature] Using the above equation, the weighted average value of volatile matter in the coal portion is 28 to 31% by weight, and the maximum fluidity (log
CPM by setting the weighted average value of DDPM) to 2.3 to 2.4.
Is 50 or more and DI ¹⁵⁰ ₁₅ is 70 or more, and a high-strength, high-reactivity coke is produced, and the method for producing a high-reactivity coke according to the first and second features.

The reasons for limitation of the present invention will now be described.

[Inerts] Inerts are those which do not show softening and melting properties in the process of dry distillation, such as powder coke, petroleum coke, pitch coke, anthracite, etc. In the method, these are blended in an amount of 10 to 30% by weight. The mixture may be a combination of these types or may be used alone, but the proportion of inactive substances having a low volatile content and a particle size of 0.3 mm or less of 90% by weight or more should be 70% of all inactive substances. -10
It is 0% by weight. The reason for this is that as the amount of the inactive substance is increased, the reactivity increases, and conversely the strength decreases, so that if the blending ratio is less than 10% by weight, the desired reactive coke cannot be obtained, and the blending ratio is also low. If it exceeds 30% by weight, the strength of the coke cannot be maintained, so the above conditions are limited.

[0012]

[Binder] The binder is an organic substance that exhibits fluidity when heated, and means, for example, a coal tar, a corter pitch, a petroleum pitch, or the like. In the production of the highly reactive coke according to the present invention, the use of the binder is 10
Weight% or less, preferably no binder is used. Although the binder is used for supplementing the strength, it also has the function of decreasing the reactivity. Therefore, when used, the above-mentioned types are used alone or in combination of several types.
The following usage restrictions must be strictly adhered to. Because 1
This is because if it is used in an amount exceeding 0% by weight, the desired highly reactive coke cannot be produced and the material cost also increases, so that the technical problem of the present invention cannot be achieved.

[0013]

[Weighted average value of volatile matter of coal part as coal property and maximum fluidity (logDDP] Weighted average value of volatile matter of coal part and maximum fluidity (logDDPM) of coal part as equation Controlling the reactivity and strength of coke prepared by the present invention, the present invention is to measure the volatile matter and maximum fluidity for each coal brand at a predetermined coal, inert material, and binder mixing ratio. , The measured value of volatile matter, and the highest fluidity, by adjusting the compounding characteristics of each brand to its logarithmic value, while maintaining the coke strength, obtain the desired reactivity coke. The volatile matter is the industrial analysis method for coals (JI specified by JIS).
S M 8812), and the maximum fluidity is the logarithmic value (log DDPM: hereinafter MF and MF) of the value measured according to the Giger-Plastometer method (JIS M 8801) which is also defined by JIS. To tell.)
To use. Therefore, using this equation, the present inventors derived the result of earnestly investigating the reactivity and strength of coke with high precision and performing the coal blending design with high precision. The formula relates to the reactivity (CRI) of coke, and is (VM) (weighted average value of volatile matter of coal portion).
It is expressed by the quadratic equation of Moreover, a, b, and c are constants obtained by a statistical method from actual measurement data. Here, CRI is a formula using other coal properties and (VM) 1
Estimating with the following formula lowers the estimation accuracy compared to the formula. Furthermore, (MF) (maximum fluidity of coal part (logDDP
When the weighted average value of M) becomes 2.40 or more, the measured value becomes lower than the estimated value, and therefore the formula is (MF) <2.40.
Must be used in the range of. The equation relates to the strength of coke (DI ¹⁵⁰ ₁₅ ), and is expressed by the first-order term of (VM), the first-order term of (MF), the interaction term of (VM) and (MF), and the constant term. Further, d, e, f, and g are constants obtained from the measured data by a statistical method.
Here, DI ¹⁵⁰ ₁₅ is a formula using other coal properties and (V
The estimation accuracy is lower than that of the equation when estimated by the equation of M), the equation of (MF), or the equation having no interaction term.

[0014]

Using the formula, the weighted average value of the volatile matter of the coal portion is 28 to 31% by weight, and the maximum fluidity (logDD
The weighted average value of PM) is set to 2.3 to 2.4 and the CRI is set to 50.
Above, about which the DI ^0.99 ₁₅ over 70] used the expression, in order to obtain as described above, the coke predetermined reactivity and strength, and accurately estimate the reactivity and strength of coke, This is for accurately designing the coal composition. Therefore, in order to obtain coke with a CRI of 50 or more and a DI ¹⁵⁰ ₁₅ of 70 or more, Y> 50 in the formula and Z> in the formula.
A range of 70 (VM) and (MF) is obtained, and coal blending design may be performed so that both satisfy. The range of the weighted average value (VM) of the volatile matter of the coal portion obtained by this method is 28 to 31% by weight, and the maximum fluidity (lo) of the coal portion is
The range of the weighted average value (MF) of gDDPM is 2.3 to
It becomes 2.4. When (VM) <28% by weight or (MF)> 2.4, the CRI becomes smaller than 50. In addition, (VM)> 31% by weight or (MF) <
When it becomes 2.3, DI ¹⁵⁰ ₁₅ becomes smaller than 70. Therefore, it is limited as described above.

[0015]

EXAMPLES The present invention will be described below based on examples.
The properties of the coke to be produced are those obtained by mixing the sinter ore in a blast furnace operation and charging it into the blast furnace to improve the reduction efficiency in the blast furnace. 45 or more, preferably 50 or more, DI
¹⁵⁰ ₁₅ is a coke having high reactivity of 70 or more.

As the inactive substance, as shown in Table 1, two types were used in combination. That is, inactive substance A
(Powder coke) has a particle size of 0.3 mm or less and a content of 9
It is 0% by weight or more and contributes to increase the reactivity of coke. Inert substance B (petroleum coke) has a volatile content of 1
It is 0% by weight or more and contributes to the increase in strength. By combining these two kinds of inactive substances, the strength of the coke can be maintained and the reactivity can be increased.

Coal having the properties shown in Table 2 was used. The dry distillation test uses a test furnace of 80 kg and the furnace temperature is 1150.
Performed at ° C.

The strength of the coke was measured by the drum strength (DI ¹⁵⁰ ₁₅ ) specified in JIS K 2151, and the reactivity was measured by the CRI. This CRI is an index showing the reactivity of coke measured by the following method. Granularity 20 ±
200 g of coke prepared to 1 mm was used at a reaction temperature of 11
The weight of the coke remaining after reacting at 00 ° C. and a CO ₂ gas flow rate of 5 Nl / min for 2 hours is measured. Its weight (Ag)
CRI is calculated by the following formula. CRI = ((200-A) / 200) × 100 (%)

Table 3 is a test investigating the influence of the compounding ratio of the inert material and the binder. Example 1 is a test within the range of the compounding ratio of the present invention. Comparative Example 1 is a case where the inactive substance is insufficient, and it can be seen that the reactivity is lowered.
Comparative Example 2 is a case where the amount of the inactive substance is too large, and it can be seen that the strength is remarkably reduced. In Comparative Example 3, it can be seen that the reactivity is lowered when the binder is too much.

Next, 75% by weight of coal and 1% of the inactive material A were added.
5% by weight, 5% by weight of the inert material B and 5% by weight of the binder were fixed, and the weighted average value of the volatile matter of the coal portion and the weighted average value of the MF were changed by changing the blending ratio of the coal. Conducted a test. FIG. 1 shows the relationship between the weighted average value of volatile matter stratified by the weighted average value of MF and the DI ¹⁵⁰ ₁₅ of coke. Further, FIG. 2 shows the relationship between the weighted average value of volatile components stratified by the weighted average value of MF and the CRI of coke. The relationship of the formula is obtained from FIG. 1, and the relationship of the formula is obtained from FIG. Y = 225.464-15.282 * (VM) + 0.322 * (VM) ² (however, (MF) <2.40) -Z = 442.274-15.781 * (VM) -145.638 X (MF) + 6.274 x (VM) x (MF) -where Y: coke reactivity (CRI) Z: coke strength (DI ¹⁵⁰ ₁₅ ) a: weighted average value of volatile matter of coal part b: Weighted average value of maximum fluidity (logDDPM) of coal portion

Therefore, the highly reactive coke having strength according to the present invention, ie, CRI of 50 or more, DI ¹⁵⁰ ₁₅
To obtain 70 or more, the formula Y> 50, and the formula Z>
70 should be satisfied, and the range satisfying these is the third
This is the range indicated by the shaded area in the figure.

[0022]

[Table 1]

[0023]

[Table 2]

[004]

[Table 3]

[0025]

Industrial Applicability Since the present invention is as described above, the following remarkable industrial effects can be obtained, and it can be distinguished from the prior art examples described. A) A coke having controlled coke strength and reactivity can be obtained by a composition using coal, an inert material and a binder, which is not found in the prior art examples. Especially strength (DI
¹⁵⁰ ₁₅ ) having a high strength of 70 or more means that the desired lump shape can be maintained during the kiln removal, which significantly improves the handling of the produced coke and reduces the cost of producing the coke. Contribute to. Further, since the CRI can be made highly reactive with 50 or more, it contributes to the remarkable improvement of the reduction efficiency in the blast furnace. B) Since the composition uses coal, an inert material, and a binder, which are not found in the prior art examples, the material cost is low, the cost is low, and the coke can be produced without damaging the room-type coke oven. Can be manufactured. C) Since it is a composition that uses coal, an inert material, and a binder, which is not found in the prior art example, as in the prior art example,
Since the tar and pitch are not evaporated by heating,
There is no environmental problem. D) If the produced high-strength, highly-reactive coke is granulated and mixed with sinter ore and charged into the blast furnace, the reduction efficiency in the blast furnace can be improved. Further, based on the improvement of the reduction efficiency, the fuel ratio is also reduced, which contributes to the reduction of the hot metal cost. E) The effects of a) to d) above contribute to the operating conditions required by the current blast furnace operation, and when viewed in the integrated pig iron production,
It is a huge effect that cannot be measured. F) Based on the above description, it can also contribute to the reduction of CO ₂ generation, which is said to be a factor of global warming problem, and its effect is immeasurable.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the weighted average value of MF and volatile matter of a coal portion and the DI ¹⁵⁰ ₁₅ of coke.

FIG. 2 is a graph showing the relationship between the MF of a coal portion, the weighted average value of each volatile component, and the CRI of coke.

FIG. 3 is a CRI that can be produced by the present invention of 50 or more;
I ^0.99 ₁₅ 70 or more co - is a graph showing the MF and volatile subranges each weighted average coal portion for the box.

Claims (3)

[Claims] 1. An inactive substance having a low volatile content and having a particle size of 0.3 mm or less and 90% by weight or more is 7 in the inactive substance.
An inactive material occupying 0 to 100% by weight is added to the raw coal 10 to 10.
Blended at a constant blending ratio in the range of 30% by weight, and as a coal property, the weighted average value of the volatile matter of the coal portion and the maximum fluidity (l
The method for producing a highly reactive coke, which comprises controlling the reactivity and strength of the coke by preparing a weighted average value of (ogDDPM) using the following formula. Y = a + b × (VM) + c × (VM) ² (where (MF) <2.40) Z = d + e × (VM) + f × (MF) + g × (VM) × (MF) ─where Y : Coke reactivity (CRI) Z: Coke strength (DI ¹⁵⁰ ₁₅ ) (VM): Weighted average value of volatile matter in coal portion (MF): Weighted average value of maximum fluidity (log DDPM) in coal portion a, b, c, d, e, f, g: constant 2. The method for producing a highly reactive coke according to claim 1, wherein the binder is blended at a constant blending ratio of 10% by weight or less containing 0. 3. Using the above equation, the weighted average value of volatile matter in the coal portion is 28 to 31% by weight, and the maximum fluidity (log
CPM by setting the weighted average value of DDPM) to 2.3 to 2.4.
Is 50 or more and DI ¹⁵⁰ ₁₅ is 70 or more, and a high-strength, high-reactivity coke is produced, and the method for producing a high-reactivity coke according to claim 1 or claim 2. [0001]