CN102245738B - Process for producing coke for blast furnace - Google Patents

Abstract

Disclosed is a process for producing coke for use in a blast furnace, the process comprising: dividing inert structures having a maximum length of 0.6 mm or larger into m size groups according to maximum length; predetermining the degree of influence (Ai (-/vol.%)) of the inert structures contained in each of all size groups (i) on the proportion of powder generated by coke surface breakage (DI150 -6); determining the inert-structure content (Ibi,j (vol.%)) in each size group (i) with respect to raw-material coal of all brands (j); pulverizing the raw-material coal according to boundary values of the contents of the coarse inert structures; determining the inert-structure content (Iai,j (vol.%)) in each size group (i) with respect to the pulverized raw-material coal of all brands (j); and blending the pulverized raw-material coal of all brands (j) so as to satisfy DI150 -6(target)- DI150 -6(ref) = Sigma j =1-n{sigma i=1-mAi*(Ibi,j-Iai,j)}*Xj.

Description

The manufacture method of blast furnace coke

Technical field

The present invention relates to have used the manufacture method that non-micro-caking coal and caking coal is coordinated to the blast furnace coke of the coal blending forming.Relate in particular to the manufacture method of following blast furnace coke, it is regardless of non-micro-caking coal and caking coal, the reduction of the coke strenth that inertia (inertness) tissue that all can be used for existing in the feed coal of inhibition by various kinds causes, thus coke strenth is improved.

The application based on December 10th, 2008 in No. 2008-314903, the Patent of Japanese publication and advocate right of priority, by its content quotation in this.

Background technology

Generally, the blast furnace coke of using as the reducing material in iron-smelting process and thermal source is manufactured by following method: the feed coal of multiple kinds is pulverized respectively, ratio in accordance with regulations coordinates, have after the coal blending of granularity of regulation thereby form, this coal blending is packed in coke-fired furnace into the destructive distillation specified time.

Now, coke strenth DI ¹⁵⁰ ₁₅formed the impact of the proterties of feed coal and the granularity of coal blending of multiple kinds of coal blending.Wherein, DI ¹⁵⁰ ₁₅being to utilize tumbler test machine that JIS K 2151 specifies to carry out the ratio (-) of 150 postrotational 15mm screen overflows, is the index that represents coke strenth (also referred to as cylinder intensity).

As affecting coke strenth DI ¹⁵⁰ ₁₅the proterties of coal, can enumerate the cohesiveness of coal.The cohesiveness of coal can be measured the high fluidity that obtain or be evaluated by the overall expansion rate of having used the swelling property test determination of dilatometer of JIS M 8801 to obtain by the fluidity test of the gieseler plastometer by having used JIS M 8801.These measured values are higher, and mobility and swelling property when the softening melting of coal are higher.

The cohesiveness of feed coal based on coal can be divided into caking coal and the low non-micro-caking coal of cohesiveness that cohesiveness is high.Mobility and the swelling property of caking coal during due to softening melting is high, therefore easily carries out coal interparticle bonding, has improved coke strenth.On the other hand, mobility and the swelling property of non-micro-caking coal during due to softening melting is low, and therefore coal is interparticle bondingly becomes insufficient.Thereby if coordinate in a large number non-micro-caking coal, coke strenth reduces.

In addition, as affecting coke strenth DI ¹⁵⁰ ₁₅the proterties of coal, can enumerate the tissue (hereinafter referred to as " inertia tissue ") by the inertness composition of softening melting forms when the heating of coal.This inertia tissue, regardless of caking coal and non-micro-caking coal, is present in coal.

Inertia tissue in coal is owing to not expanding when the softening melting of coal, thereby it is interparticle bonding to hinder the coal being undertaken by the expansion of coal.And, inertia tissue be difficult to coal again solidify time shrink, therefore in the time of the contraction of coal, chap.Therefore, the inertia tissue in coal becomes the reason that coke strenth is reduced.

On the other hand, the loose density of the granularity of coal blending when packing coke-fired furnace into exerts an influence.In the case of the granularity of coal blending is thick, the interstitital texture of the coal blending in stove approaches the closeest interstitital texture, and the loose density while packing coke-fired furnace into improves, and in the softening melting of coal and while expanding, coal is interparticle bondingly becomes easy.But, if there is thick coal particle in coal blending, bring out crackle from this particle surface, the strength at break of coke reduces.

On the contrary, if the undersized of coal blending, the loose density while packing coke-fired furnace into reduces, and the interparticle space of coal increases.Therefore, in the softening melting of coal and while expanding, coal is interparticle bondingly becomes insufficient, and coke strenth reduces.

Therefore, generally need to be by the proterties homogenization of coal, and loose density when coke is packed into maintains the level of regulation, and coke strenth is improved.For this reason, the mode that becomes 70～85 quality % according to the accumulation ratio below the particle diameter 3mm of coal blending has been adjusted the granularity of coal blending entirety.

In recent years, be accompanied by the exhaustion of coal resources, the not only usage quantity of the micro-caking coal of right and wrong, in caking coal and non-micro-caking coal, the amount of contained inertia tissue also increases.Therefore,, even if, caking coal many in the usage quantity of non-micro-caking coal and non-micro-caking coal contain a large amount of inertia tissues, also require to manufacture high-intensity coke.

Use becomes non-micro-caking coal of reason that coke strenth reduces and/or the coal that contains a large amount of inertia tissues, and on the basis of coke strenth of guaranteeing prescribed level, it is important that the coal of each kind of formation coal blending is adjusted to granularity by pulverizing.Therefore, proposed the breaking method of the corresponding coal of the proterties of several and coal and kind in the past and utilized the manufacture method (with reference to patent documentation 1～3) of the high-strength coke of this breaking method.

For example, in patent documentation 1, by the coal of multiple kinds be divided into average reflectance be non-micro-caking coal, average reflectance below 0.9 volume % exceed 0.9% and the total amount of inertia tissue be more than 35 volume % high inertia coal and average reflectance exceed 0.9% and the total amount of inertia tissue lower than these 3 groups, the low dark decay coal of 35 volume %.And then, be that particle diameter that the mass ratio below 3mm is high, the high inertia coal of mass ratio below 3mm than the particle diameter of coal blending is that particle diameter that the mass ratio below 3mm is non-micro-caking coal is that mass ratio particle diameter following, low dark decay coal below 3mm is that the mode that the mass ratio below 3mm is the mass ratio below 3mm lower than the particle diameter of high inertia coal is pulverized according to the particle diameter of non-micro-caking coal.Then, all coal of pulverizing is mixed, carry out destructive distillation with coke-fired furnace, manufacture coke.

But, even by the method for recording in patent documentation 1, coke strenth DI ¹⁵⁰ ₁₅be 78 left and right, existence cannot obtain the situation of desirable coke strenth.

In addition,, in patent documentation 2, a part for the coal many amount of coal high hardness or inertia tissue is classified into coal and the little coal of particle diameter that particle diameter is large.Coal large this particle diameter is pulverized to (the first pulverizing process), the coal coal little with above-mentioned particle diameter that has carried out processing in the first pulverizing process is coordinated.And then the coal that this cooperation is formed is further pulverized (the second pulverizing process), coordinates remaining coal.Then, the coal that this cooperation is formed is pulverized (the 3rd pulverizing process), coordinates with the coal that has carried out processing in above-mentioned the second pulverizing process, packs in coke-fired furnace, manufactures coke.

But, even by the method for recording in patent documentation 2, coke strenth DI ³⁰ ₁₅be up to 94.3 and (be equivalent to DI ¹⁵⁰ ₁₅be 84 left and right), existence cannot obtain the situation of desirable coke strenth.

Like this, in the method for recording at patent documentation 1 and 2, mainly by kinds such as proterties, non-micro-caking coal such as the average reflectance corresponding to coal, inertia tissues, coal is pulverized, made coal organize homogenization, and the size-grade distribution of coal blending entirety is adjusted, coke strenth is improved.But, in the method for recording at patent documentation 1 and 2, there is coke strenth DI ¹⁵⁰ ₁₅cannot reach the situation of expected value.

In addition, according to the present inventors' result of study, confirmed that coke strenth is not arranged by the total amount of inertia tissue, but be subject to thick inertia tissue domination more than specific dimensions.For example, during the coal carrying out in the total amount of patent documentation 1 and the 2 disclosed inertia tissues based in coal is pulverized, the situation that exists coke strenth fully to improve.

In patent documentation 3, during the granularity of the coal carrying out in the total amount of the inertia tissue based in coal is adjusted, there is the understanding of limit from the raising of coke strenth, investigated the cumulative volume ratio of thick inertia tissue of the maximum length having more than 1.5mm and the relation of grinding particle size in coal blending.From this relation, propose to make the particle size adjusting method of the coal blending of high-strength coke.

The particle size adjusting method of the coal blending proposing according to patent documentation 3, even if a large amount of use becomes inferior non-micro-caking coal of the reason of coke strenth reduction, also can stably manufacture the intensity DI with 86～87 left and right ¹⁵⁰ ₁₅coke.

But, in the method, at the high coke strenth DI requiring more than 86.5 ¹⁵⁰ ₁₅situation under, in order to reduce the cumulative volume ratio of thick inertia tissue, need to improve the crush strength of pulverizer coal is pulverized.But if improve the crush strength of pulverizer, particle diameter is that the dust coal below 0.3mm increases, the loose density of coal blending entirety also reduces.Therefore, existence cannot realize the more than 86.5 coke strenth DI as target ¹⁵⁰ ₁₅situation.

In addition, particle diameter is increase, the reduction of tar quality etc. that the problem of the airborne dust of the increase of the dust coal below 0.3mm when can causing at the course of conveying of coal and packing coke-fired furnace into, the coke that caused by the furnace wall carbon adhesion amount increase in coke-fired furnace are extruded load, therefore not preferred.

Therefore, seeking the particle diameter that can suppress to be accompanied by the strong pulverizing of the coal that comprises thick inertia tissue and occur is the increase of the dust coal below 0.3mm and the loose density (t/m of coal blending entirety ³) reduction, and can stablize and effectively improve the particle size adjusting method of coke strenth.

Prior art document

Patent documentation

Patent documentation 1: TOHKEMY 2006-273884 communique

Patent documentation 2: TOHKEMY 2006-348309 communique

Patent documentation 3: TOHKEMY 2004-339503 communique

Summary of the invention

Invent problem to be solved

The object of the invention is the above-mentioned practical situation in view of prior art, the manufacture method of following blast furnace coke is provided, it is by effectively pulverizing the coal that comprises the thick inertia tissue with maximum length more than 0.6mm that becomes the reason of strength decreased, and be that the reduction of the increase of the dust coal below 0.3mm and the loose density of coal blending entirety suppresses to being accompanied by the particle diameter that coal pulverizes, thereby can stablize and effectively improve coke strenth.

For solving the means of problem

Present inventor conducts in-depth research the particle size adjusting method of coal and the matching requirements of coal of utilizing pulverizing to carry out in order to solve above-mentioned problem.

, the present inventors are divided into size zoning i (=1～m[natural number]) by inertia tissue by maximum length.And the present inventors have pre-determined inertia by each size zoning i and have organized STRENGTH ON COKE surface breakdown powder rate (DI ¹⁵⁰ _-6) degree of impact and/or inertia organize STRENGTH ON COKE volumetric fracture of rock powder rate (DI ¹⁵⁰ _6-15) degree of impact.Its result is distinguished: if consider that the difference of these degree of impact adjusts pulverizing and the cooperation of feed coal, can obtain the coke strenth as target.

The present invention is based on above-mentioned opinion and make, its main idea is as described below.

(1) a kind of manufacture method of blast furnace coke, it packs coal blending in coke-fired furnace into, described coal blending is the feed coal of multiple kinds to be pulverized and coordinated by each kind form, it is characterized in that, (A) (A1) is that more than 0.6mm inertia tissue is divided into according to maximum length the size zoning that size zoning 1 is m to the size zoning number of size zoning m by maximum length; (A2) for described size zoning 1 to all size zoning i of described size zoning m (=1～m[natural number]), the coke surface based on coke is destroyed powder rate DI ¹⁵⁰ _-6, the inertia that pre-determines size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/), under the space compactedness Sv × Bd when coal of the described coal blending that the loose density Bd when specific volume Sv of described coke in the time that the coal by described coal blending is softening packs into coal obtains softens, the coal destructive distillation of the inertia tissue that contains described size zoning i is obtained; (B) mode that (B1) becomes 70～85 quality % for the accumulation ratio according to below particle diameter 3mm has been carried out the kind 1 the adjusted feed coal to all kind j of kind n (=1～n[natural number]) to granularity, measure the content (volume %) of the thick inertia tissue with maximum length more than 1.5mm and the described size zoning 1 content Ib to the inertia tissue of all size zoning i of described size zoning m _{i, 1}(volume %); (B2) measured value of the content based on described thick inertia tissue (volume %), is set in the cut off value of the content of described thick inertia tissue in the scope of 5～7 volume %; (C) content that (C1) feed coal of all kind j of described kind 1 to described kind n is divided into described thick inertia tissue is that the content of the more than described cut off value coal that contains high inertia and described thick inertia tissue is lower than these 2 kinds, the coal that contains low dark decay of described cut off value; (C2) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is pulverized the feed coal of the kind of the coal that contains low dark decay described in being divided into; (C3) according to accumulation ratio below particle diameter 3mm than described in contain low dark decay the particle diameter 3mm of coal below the large mode of accumulation ratio, the feed coal of the kind of the coal that contains high inertia described in being divided into is pulverized; (C4) for the feed coal of all kind j of the described kind 1 to described kind n after pulverizing, measure the content Ia of described size zoning 1 to the inertia tissue of all size zoning i of described size zoning m _{i, j}(volume %); (D) at DI ¹⁵⁰ _-6(target) be target value (-) ("-" represents zero dimension), the DI of coke strenth ¹⁵⁰ _-6(ref) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm for all kind j for described kind 1 to described kind n adjusts and coordinates coke strenth, the X of the coal blending obtaining to the granularity of feed coal _jfor forming in the situation of mixing ratio of feed coal of kind j of coal blending, according to meeting DI ¹⁵⁰ _-6(target)-DI ¹⁵⁰ _-6(ref)=∑ _j=1～n{ ∑ _i=1～ma _i× (Ib _{i, j}-Ia _{i, j}) × X _jthe feed coal of all kind j of the described kind 1 to described kind n of mode after to described pulverizing coordinate.

(2) a kind of manufacture method of blast furnace coke, it packs coal blending in coke-fired furnace into, described coal blending is the feed coal of multiple kinds to be pulverized and coordinated by each kind form, it is characterized in that, (A) (A1) is that more than 0.6mm inertia tissue is divided into according to maximum length the size zoning that size zoning 1 is m to the size zoning number of size zoning m by maximum length; (A2) for described size zoning 1 to all size zoning i of described size zoning m (=1～m[natural number]), the coke surface based on coke is destroyed powder rate DI ¹⁵⁰ _-6and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15, the inertia that pre-determines size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/), under the space compactedness Sv × Bd when coal of the described coal blending that the loose density Bd when specific volume Sv of described coke in the time that the coal by described coal blending is softening packs into coal obtains softens, the coal destructive distillation of the inertia tissue that contains described size zoning i is obtained; (B) mode that (B1) becomes 70～85 quality % for the accumulation ratio according to below particle diameter 3mm has been carried out the kind 1 the adjusted feed coal to all kind j of kind n (=1～n[natural number]) to granularity, measure the content (volume %) of the thick inertia tissue with maximum length more than 1.5mm and the described size zoning 1 content Ib to the inertia tissue of all size zoning i of described size zoning m _{i, j}(volume %); (B2) measured value of the content based on described thick inertia tissue (volume %), is set in the cut off value of the content of described thick inertia tissue in the scope of 5～7 volume %; (C) content that (C1) feed coal of all kind j of described kind 1 to described kind n is divided into described thick inertia tissue is that the content of the more than described cut off value coal that contains high inertia and described thick inertia tissue is lower than these 2 kinds, the coal that contains low dark decay of described cut off value; (C2) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is pulverized the feed coal of the kind of the coal that contains low dark decay described in being divided into; (C3) according to accumulation ratio below particle diameter 3mm than described in contain low dark decay the particle diameter 3mm of coal below the large mode of accumulation ratio, the feed coal of the kind of the coal that contains high inertia described in being divided into is pulverized; (C4) for the feed coal of all kind j of the described kind 1 to described kind n after pulverizing, measure the content Ia of described size zoning 1 to the inertia tissue of all size zoning i of described size zoning m _{i, j}(volume %); (D) at DI ¹⁵⁰ ₁₅(target) be target value (-), the DI of coke strenth ¹⁵⁰ ₁₅(ref) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm for all kind j for described kind 1 to described kind n adjusts and coordinates coke strenth, the X of the coal blending obtaining to the granularity of feed coal _jfor forming in the situation of mixing ratio of feed coal of kind j of coal blending, according to meeting DI ¹⁵⁰ ₁₅(target)-DI ¹⁵⁰ ₁₅(ref)=∑ _j=1～n{ ∑ _i=1～ma _i× (Ib _{i, j}-Ia _{i, j})+∑ _i=1～mb _i× (Ib _{i, j}-Ia _{i, j}) × X _jthe feed coal of all kind j of the described kind 1 to described kind n of mode after to described pulverizing coordinate.

(3), in the manufacture method of the blast furnace coke of recording in above-mentioned (1) or (2), can be that the inertia tissue below 3mm is divided into 2 above size zonings by maximum length.

(4), in the manufacture method of the blast furnace coke of recording in above-mentioned (1) or (2), can be that inertia tissue more than 3mm is divided into 2 above size zonings by maximum length.

(5) in the manufacture method of the blast furnace coke of recording in above-mentioned (1) or (2), described size zoning can be divided in the following manner: size zoning is counted to m and be made as 5, more than being divided into 0.6mm and lower than the size zoning 1 (i=1) of 1.5mm, more than 1.5mm and lower than the size zoning 2 (i=2) of 3mm, more than 3mm and lower than the size zoning 3 (i=3) of 5mm, more than 5mm and lower than the size zoning 4 (i=4) of 10mm and size zoning 5 (i=5) more than 10mm.

Invention effect

According to the present invention, be that more than 0.6mm inertia tissue is divided according to maximum length by, maximum length that coke strenth reduces by causing, and pre-determine the degree of impact of each size matter on Coke Strength of inertia tissue, on the different basis of considering this degree of impact, effectively coal pulverized and coordinated, thereby can not cause the reduction that particle diameter is the increase of the dust coal below 0.3mm and the loose density of coal blending, can manufacture the coke with very high strength.

In addition, according to the present invention, even owing to improving the usage rate of cheap and inferior non-micro-caking coal, also the feed coal of multiple kinds can be carried out to modularization according to the content of thick inertia tissue more than 1.5mm, and pulverize and coordinate on the basis of degree of impact of size matter on Coke Strength of considering inertia tissue, under the high state of space compactedness in coke-fired furnace, by coal blending destructive distillation, therefore can manufacture the coke of high strength and homogeneous.

Brief description of the drawings

Fig. 1 is space compactedness Sv × Bd and the coke strenth DI while representing that coal is softening ¹⁵⁰ ₁₅the figure of relation.

Fig. 2 represents the inertia tissue that exists in coke and the figure of its perienchyma.

Fig. 3 is the figure of the distribution of sizes of the inertia tissue in the coal blending (No.1～No.7) that represents to contain the inertia tissue that size zoning is different.

Fig. 4 A is the coke surface destruction powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.05, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _-6figure.

Fig. 4 B is the coke surface destruction powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.16, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _-6figure.

Fig. 4 C is the coke surface destruction powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.29, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _-6figure.

Fig. 5 A is the coke volumetric fracture of rock powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.05, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _6-15figure.

Fig. 5 B is the coke volumetric fracture of rock powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.16, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _6-15figure.

Fig. 5 C is the coke volumetric fracture of rock powder rate DI that is illustrated in the coke under the condition that the space compactedness (Sv × Bd) of coal when softening is 1.29, the coal destructive distillation that comprises the inertia tissue that size zoning is different being obtained ¹⁵⁰ _6-15figure.

The coke that under the condition that Fig. 6 A is is 1.05 for the space compactedness (Sv × Bd) in the time that coal is softening, destructive distillation obtains illustrates that the inertia of size zoning i organizes STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ifigure.

The coke that under the condition that Fig. 6 B is is 1.16 for the space compactedness (Sv × Bd) in the time that coal is softening, destructive distillation obtains illustrates that the inertia of size zoning i organizes STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ifigure.

The coke that under the condition that Fig. 6 C is is 1.29 for the space compactedness (Sv × Bd) in the time that coal is softening, destructive distillation obtains illustrates that the inertia of size zoning i organizes STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ifigure.

Fig. 7 is the figure that represents the relation of the cumulative volume ratio of the accumulation ratio below the particle diameter 3mm of the coal (A coal) that contains high inertia and inertia tissue more than each size.

Fig. 8 is the figure that represents the relation of the cumulative volume ratio of the accumulation ratio below the particle diameter 3mm of the coal (B coal) that contains low dark decay and inertia tissue more than each size.

Embodiment

In general, coke strenth is arranged by the defect in the physical property such as the Young's modulus of coke matrix and coke.But, under the kind of the feed coal using in the common manufacturing process at blast furnace coke, their cooperation ratio and the condition of common pyrolysis temperature, the not too large variation of the physical property such as the Young's modulus of the coke matrix of generation.Therefore, can think that coke strenth is arranged by the defect in coke.

This two macrospecies of crack of producing when defect in the coke of domination coke strenth is structurally mainly divided into the interparticle poor attachment of coal that produces in the time of softening expansion of coal and thick pore and the contraction after the solidifying again of coal.

The feed coal of common coke manufacture use starts softening and expands in coke-fired furnace at the temperature of 400 DEG C of front and back, solidifies, coke at the temperature of 500 DEG C of front and back again.

In the time of the softening and expansion of coal, for the coal that makes softening melting enters in the interparticle space of coal and makes coal particle fully bonding each other, loose density when coal need to be packed into and the cohesiveness of coal (expression mobility and expansile index) be related to optimization.

That is to say, the voidage (inverse of loose density) while packing into respect to coal, in the case of the cohesiveness of coal is low, the softening of coal and the coal of softening melting while expanding cannot be by the abundant landfill in interparticle coal space.For this reason, the ground free expansion that do not carry the baby of coal particle, coal particle each other fully not solidifying again under the state of contact, coke, therefore coke strenth reduces.

In addition,, the softening of coal and while expanding, in coal particle, result from volatile component and the bubble that produces cannot escape to outside system (in coal particle) and grow up.In this process, if the chainless ground free expansion of coal particle makes the top layer wall attenuation gradually of coal particle by the growth of bubble, and then the bubble in coal particle destroys top layer wall and breaks.Grow up in coal particle by bubble or by bubble break and bubble formed gross blow hole connected to each other as destroy starting point become make coke strenth reduce reason.

Space compactedness (Sv × Bd) domination when coal that loose density Bd when specific volume Sv when the interparticle generation bonding and thick pore of above-mentioned coal is subject to by coal softening and coal pack into obtains is softening.

Space compactedness (Sv × Bd) and coke strenth DI when Fig. 1 represents that coal is softening ¹⁵⁰ ₁₅an example of relation.As can be seen from Figure 1, by space compactedness (Sv × Bd) is made as to more than 1.0 suitable values, the generation of the interparticle poor attachment of coal and thick pore is suppressed, and coke strenth improves.

In addition, volume when specific volume Sv when coal softening can be by the maximum swelling of coal is obtained, and the volume when maximum swelling of described coal can use the swelling property testing apparatus of the dilatometer that has utilized JIS M 8801 measure and obtain.

On the other hand, when the contraction after the solidifying again of coal the crack that produces because of shrinking percentage different generation the mutually of coal particle.The inertia tissue existing in coal is compared with softening vitrinite's tissue and chitin group tissue of melting by the heating of coal, volatile component is few, in the time of the softening and expansion of coal, expands hardly, after solidifying, shrinks hardly again.

Therefore, can think coal again solidify after contraction time, poor due to the shrinking percentage of the softening melting tissues such as the shrinking percentage of inertia tissue and vitrinite's tissue or chitin group tissue, at the generation of interfaces stress of inertia tissue, in inside or the periphery generation crack of inertia tissue.

Fig. 2 represents the inertia tissue that exists in coke and an example of perienchyma thereof.Inertia is not organized and is softened melting because of heating, remains in coke.Therefore,, by using the coke shown in microscopic examination Fig. 2 or the section structure of coal, can measure the size of inertia tissue.In addition, in the present invention, the size of the inertia tissue in coal refers to maximum length (mm).

For example, the size (maximum length) of the inertia tissue in Fig. 2 is about 2mm, and still, inertia is organized in size widely (maximum length) the scope existence with 0.1 μ m～10mm in coal conventionally.

The present inventors' result of study confirmed, making the crack in coke that coke strenth significantly reduces is the inside of thick inertia tissue of size (maximum length) or the large fracture of the size (maximum length) of the mm level (more than 1.0mm) that periphery generates at mm level (more than 1.0mm).For example, in Fig. 2, generate and have crack at the periphery of inertia tissue.

That is to say, according to the failure condition formula of Ge Lifeisi (for example, " J.F.Knott (Gong Benbo translates), the basis of mechanics " destroy ", p.107 " [training wind shop (1977) distribution] with reference to), there is expansion and expand in large fracture with low stress compared with cracklin.Therefore, the large fracture of the mm level generating at inside or the periphery of thick inertia tissue, in the time that coke is subject to impacting, works as the starting point (defect) of brittle rupture.

Therefore, the intensity of the coke of the large fracture that contains a large amount of mm levels (more than 1.0mm) significantly reduces, easily efflorescence.

According to above opinion, in patent documentation 3, as the particle size adjusting method of the coal blending for improving coke strenth, the maximum length in the coal based on formation coal blending is the cumulative volume ratio of thick inertia tissue more than 1.5mm and the relation of grinding particle size, and coal is pulverized.

According to the particle size adjusting method of disclosed coal blending in patent documentation 3, even if a large amount of inferior non-micro-caking coal that uses the reason that becomes strength decreased also can stably be manufactured coke strenth DI ¹⁵⁰ ₁₅it is the coke of 86～87 left and right.

But, in aforesaid method, realize more than 86.5 high coke strenth DI in hope ¹⁵⁰ ₁₅situation under, in order to reduce the cumulative volume ratio of above-mentioned thick inertia tissue, need to improve the crush strength of pulverizer.But if improve crush strength, particle diameter is the dust coal increase below 0.3mm, the loose density of the coal blending in coke-fired furnace also reduces, and therefore has the more than 86.5 coke strenth DI that cannot realize as target ¹⁵⁰ ₁₅situation.

In addition, particle diameter is the problem of the increase of the dust coal below the 0.3mm airborne dust when causing the course of conveying of coal and pack coke-fired furnace into, increase, the reduction of tar quality etc. of being extruded load by the coke causing adhering to of the carbon in coke-fired furnace, therefore not preferred.

Therefore, the present inventors are the coke that the reduction manufacture of the increase of the dust coal below 0.3mm and the loose density of coal blending has very high strength in order not cause particle diameter, thick inertia tissue is divided by maximum length, pre-determine the degree of impact of every kind of size matter on Coke Strength of inertia tissue, and then consider the different of this degree of impact and studied effective pulverizing and fitting method.

Particularly, as described below, the different condition of space compactedness (Sv × Bd) while softening with respect to the coal of coal blending, the coal blending that modulation contains the inertia tissue that size zoning is different.By after these coal blending destructive distillation, measure coke strenth DI ¹⁵⁰ ₁₅, and studied the size zoning matter on Coke Strength DI of inertia tissue ¹⁵⁰ ₁₅impact.

Be adjusted to No.1:0.1mm by screening above and above and above and above and above and above and lower than 10.0mm and No.7:10mm is above and lower than the inertia tissue of the particle size fraction of these 7 zonings of 15mm lower than 5.0mm, No.6:5.0mm lower than 3.0mm, No.5:3.0mm lower than 1.5mm, No.4:1.5mm lower than 0.6mm, No.3:0.6mm lower than 0.3mm, No.2:0.3mm.Prepare inertia different these sizes to organize respectively with in 10% coal that the is coupled to single variety coal of the kind of inertia tissue (hardly containing) and the coal blending obtaining.Space compactedness (Sv × Bd) in the time that the coal of coal blending is softening is under 1.05,1.16 and 1.29 these 3 conditions, these 7 kinds (corresponding to the size zoning of the inertia tissue of No.1～7) coal blendings to be carried out to destructive distillation by gas retort and manufactured coke.

In addition, by the following method, the size (maximum length) of inertia tissue in mensuration coal and the volume fraction of the inertia tissue of each size zoning.

The volume fraction of the size (maximum length) of the inertia tissue in coal and the inertia tissue of each size zoning for example can be measured by the method for recording in TOHKEMY 2004-339503 communique.

That is to say, in the cut surface of the coke obtaining, imbed resin, after with microscope, this cut surface being taken pictures, the inertia tissue in comparison film carries out mark.Use image analysis software, measured size (maximum length) and its area occupation ratio (area %) of inertia tissue by this photo.Can be obtained by these measured values the volume fraction (volume %) of inertia tissue to each size zoning of inertia tissue.

Fig. 3 represents the distribution of sizes of the inertia tissue existing in 7 kinds of coal blendings (No.1～7).In addition, the inertia tissue shown in the transverse axis of Fig. 3 is of a size of the maximum length (mm) of the inertia tissue of measuring by aforesaid method.The longitudinal axis represents the volume fraction (volume %) of the inertia tissue of measuring by each size zoning.

It is that the coke surface of the coke that under 1.05,1.16 and 1.29 these 3 conditions, coal blending (No.1～7) destructive distillation obtained is destroyed powder rate DI that Fig. 4 A～C is illustrated in the coal of above-mentioned 7 kinds of coal blendings (No.1～7) the space compactedness (Sv × Bd) when softening ¹⁵⁰ _-6.Equally, Fig. 5 A～C represents the coke volumetric fracture of rock powder rate DI of the coke obtaining ¹⁵⁰ _6-15.

In addition, as shown in Figure 1, at Sv × Bd lower than 1.0 in the situation that, coke strenth DI ¹⁵⁰ ₁₅reduce, cannot realize in the present invention coke strenth (the more than 86.5 coke strenth DI as target ¹⁵⁰ ₁₅).The condition of the space compactedness (Sv × Bd) when therefore, coal being softened is set as more than 1.0.

Here, coke surface is destroyed powder rate DI ¹⁵⁰ _-6represent to utilize tumbler test machine that JIS K 2151 specifies to carry out the ratio (powder rate) (-) of 150 6mm screen underflows after whirl test, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15represent to utilize tumbler test machine that JIS K 2151 specifies to carry out 150 6mm screen overflows after whirl test and the ratio (powder rate) (-) of 15mm screen underflow.

As the level of control of common coke strenth and the coke strenth DI using ¹⁵⁰ ₁₅destroy powder rate DI with coke surface ¹⁵⁰ _-6with coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15relation can be represented by following formula (2).

DI ¹⁵⁰ ₁₅＝100-(DI ¹⁵⁰ _-6+DI ¹⁵⁰ _6-15) (2)

Coke surface is destroyed powder rate DI ¹⁵⁰ _-6owing to destroying, unit is little, therefore becomes poor attachment portion, the minute sized pore by the interparticle part of coal and results from the powder rate of the powder that the tiny flaw of inertia tissue produces.In addition coke volumetric fracture of rock powder rate DI, ¹⁵⁰ _6-15with DI ¹⁵⁰ _-6compare, owing to destroying, unit is large, therefore becomes the pore by linking the coarse size such as pore and results from the powder rate of the powder that the thick defect of inertia tissue of coarse size produces.

According to Fig. 4 A, space compactedness (Sv × Bd) when the coal of coal blending softens is 1.05 o'clock, in the situation (size of the inertia tissue obtaining by screening is lower than the coal blending of No.1～2 of 0.6mm) of the size (maximum length) of the inertia tissue existing in coal blending lower than 0.6mm, coke surface is destroyed powder rate DI ¹⁵⁰ _-6be low to moderate approximately 13.0.In addition, in this situation, size (maximum length) the STRENGTH ON COKE surface breakdown powder rate DI of the inertia tissue existing in coal blending ¹⁵⁰ _-6impact little.

And then, it is above and lower than in the situation of 5.0mm (the inertia tissue obtaining by screening be of a size of 0.6mm above and lower than the coal blending of No.3～5 of 5.0mm) that the inertia tissue existing in coal blending is of a size of 0.6mm, when the size of inertia tissue increases, coke surface is destroyed powder rate DI ¹⁵⁰ _-6increase.

In addition, if the inertia tissue existing in coal blending is of a size of 5mm above (the inertia tissue obtaining by screening be of a size of 5.0mm above and lower than the coal blending of No.6～7 of 15mm), coke surface destruction powder rate DI ¹⁵⁰ _-6constant in approximately 16.2 (-).

According to Fig. 4 B, space compactedness (Sv × Bd) when the coal of coal blending softens is 1.16 o'clock, in the situation (size of the inertia tissue obtaining by screening is lower than the coal blending of No.1～3 of 1.5mm) of the size (maximum length) of the inertia tissue existing in coal blending lower than 1.5mm, coke surface is destroyed powder rate DI ¹⁵⁰ _-6be low to moderate approximately 12.2.In addition, in this case, can infer size (maximum length) the STRENGTH ON COKE surface breakdown powder rate DI of the inertia tissue existing in coal blending ¹⁵⁰ _-6impact little.

And then, the inertia tissue existing in coal blending be of a size of 1.5mm with and lower than in the situation of 10mm (the inertia tissue obtaining by screening be of a size of 1.5mm more than and lower than the coal blending of No.4～6 of 10mm), when the length dimension of inertia tissue increases, coke surface is destroyed powder rate DI ¹⁵⁰ _-6increase.

In addition, if the inertia tissue existing in coal blending be of a size of 10mm more than (the inertia tissue obtaining by screening be of a size of 10mm more than and lower than the coal blending of the No.7 of 15mm), coke surface is destroyed powder rate DI ¹⁵⁰ _-6constant in approximately 14.2 (-).

According to Fig. 4 C, space compactedness (Sv × Bd) in the time that the coal of coal blending softens is 1.29 o'clock, in the situation (size of the inertia tissue obtaining by screening is lower than the coal blending of No.1～4 of 3.0mm) of the size (maximum length) of the inertia tissue existing in coal blending lower than 3.0mm, coke surface is destroyed powder rate DI ¹⁵⁰ _-6be low to moderate approximately 11.7.In addition, in this case, can infer size (maximum length) the STRENGTH ON COKE surface breakdown powder rate DI of the inertia tissue existing in coal blending ¹⁵⁰ _-6impact little.

And then, if the inertia tissue existing in coal blending is of a size of 3mm above (the inertia tissue obtaining by screening be of a size of 3.0mm above and lower than the coal blending of No.5～7 of 15mm),, when the size of inertia tissue increases, coke surface is destroyed powder rate DI ¹⁵⁰ _-6increase.

In addition, can confirm from other experimental results of the present inventors, the inertia tissue existing in coal blending is of a size of in situation more than 15mm, and coke surface is destroyed powder rate DI ¹⁵⁰ _-6for approximately 13.2.That is, in this case, the situation of coal blending of No.7 is almost identical with using, if more than the inertia tissue existing in coal blending is of a size of 10mm, and coke surface destruction powder rate DI ¹⁵⁰ _-6become constant.

Above, according to Fig. 4 A～C, be accompanied by the rising of the coal of the coal blending space compactedness (Sv × Bd) when softening, affect coke surface destruction powder rate DI ¹⁵⁰ _-6the size (maximum length) of inertia tissue shift to coarse grain side.In addition,, space compactedness (Sv × Bd) when the known coal in coal blending is softening is high, compared with the low situation of space compactedness (Sv × Bd) when softening with the coal of coal blending, coke surface is destroyed powder rate DI ¹⁵⁰ _-6increment rate with respect to the size of inertia tissue is few.

Described in thinking that it the reasons are as follows.

The size in crack (be full of cracks) and the size of inertia tissue of in the situation that coke destroys, organizing periphery to produce in inertia are proportional.About the intensity of the fragility body as coke, having length is that destruction toughness value K under the situation lower plane tensile stress state in crack of 2c is represented by following formula (3) (the failure condition formula of Florence Griffith).

$K=\mathrm{\σ}\sqrt{}\left(\mathrm{\πc}\right)---\left(3\right)$

K[Pam ^1/2] for destroying toughness value, σ [Pa] is tensile stress, c[m] be crack half length (flaw size).

According to above-mentioned formula (3), can predict that crack starts the threshold value of the flaw size c of expansion., the right while reaching the K value on the left side, progress of fracture.

Can think because the interparticle cementability of coal improves, the rising of the space compactedness (Sv × Bd) when thereby the coal that is accompanied by coal blending is softening, the destruction toughness value K of the inertia tissue on the left side of above-mentioned formula (3) matrix portion around rises.

Therefore, the crack on the right of above-mentioned formula (3) starts the flaw size c value increase of expansion.Therefore,, space compactedness (Sv × Bd) when softening at the coal of coal blending is large, even can think the crack being produced by large-sized inertia tissue, crack is also difficult to expand.

According to these opinions, coke surface is destroyed powder rate DI ¹⁵⁰ _-6be subject to the inertia tissue impact of size (maximum length) more than 0.6mm, change according to the size zoning of inertia tissue.Therefore,, for inertia tissue more than 0.6mm, set STRENGTH ON COKE surface breakdown powder rate DI according to each size zoning of inertia tissue ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/).Under the condition shown in Fig. 4 A～C, need to be more than 0.6mm and for example, lower than between 15mm, the size field of inertia tissue (being divided into 5 size zonings, more than 0.6mm and lower than more than 1.5mm, 1.5mm and lower than more than 3mm, 3mm and lower than more than 5mm, 5mm and lower than 10mm, more than 10mm), and each size zoning of inertia tissue is set to degree of impact A _i.

As mentioned above, inertia tissue more than 0.6mm is divided into 5 size zonings, still, size zoning not must be defined as 5.According to the maximum length of inertia tissue, suitably set the interval of the size zoning of inertia tissue, the size zoning that is divided into proper amt (i=1～m[natural number]) is counted m.Be, that more than 0.6mm inertia tissue is divided into according to maximum length the size zoning that size zoning 1 is m to the size zoning number of size zoning m by maximum length.

On the other hand, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15as shown in Fig. 5 A～C, under the condition that space compactedness (Sv × Bd) in the time that the coal of coal blending softens is arbitrary value, in the situation (size of the inertia tissue obtaining by screening is lower than the coal blending of No.1～5 of 5.0mm) of the size (maximum length) of the inertia tissue existing lower than 5.0mm, be low to moderate approximately 1.3 (-) in coal blending.In addition, in this case, size (maximum length) the STRENGTH ON COKE volumetric fracture of rock powder rate DI of the inertia tissue existing in coal blending ¹⁵⁰ _6-15impact little.

And then, the inertia tissue existing in coal blending is of a size of in situation (the inertia tissue obtaining by screening is of a size of the coal blending of No.6～7 more than 5.0mm) more than 5mm, when the size of inertia tissue increases, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15increase.

In addition, can confirm from other experimental results of the present inventors, the inertia tissue existing in coal blending is of a size of more than 15mm, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15for approximately 2.2.That is, can confirm in this case coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15the situation of coal blending of No.7 is almost identical with using, if more than the size of the inertia tissue existing in coal blending becomes 10mm, and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15become constant.

As shown in Fig. 5 A～C, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15space compactedness (Sv × Bd) when softening according to coal with respect to the increment rate of the size of inertia tissue changes.Its reason is to affect coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15large fracture (be full of cracks) and the inertia tissue of size around the destruction toughness value K value of matrix portion independently expand.

According to these opinions, coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15be subject to the inertia tissue impact of size (maximum length) more than 5.0mm, change according to the size zoning of inertia tissue.Therefore, with A _iequally, for inertia tissue more than 0.6mm, set STRENGTH ON COKE volumetric fracture of rock powder rate DI according to each size zoning of inertia tissue ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/).In the condition shown in Fig. 5 A～C, for example, for degree of impact B _ithe 0.6mm that diminishes is above and lower than the inertia tissue of 5mm, at least sets 1 size zoning (for example, 0.6mm is above and lower than 5mm), at degree of impact B _iin the situation more than 5mm increasing, at least set 2 size zonings (for example,, more than 5mm and lower than 10mm, more than 10mm).In this situation, the size zoning of inertia tissue need to be added up to and is divided into 3 size zonings, each size zoning is set to degree of impact B _i.

In addition, with setting degree of impact A _isituation identical, suitably set the interval of the size zoning of inertia tissue according to the maximum length of inertia tissue, the size zoning number that is divided into suitable quantity (i=1～m[natural number]) is m.The size zoning that, to be more than 0.6mm inertia tissue by maximum length be divided into size zoning 1 and count m to the size zoning of size zoning m according to maximum length.

According to the result of Fig. 4 A～C and Fig. 5 A～C, organize STRENGTH ON COKE surface breakdown powder rate DI in the inertia of having set size zoning i shown in Fig. 6 A～C ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) example.Space compactedness (Sv × Bd) when the coal of the coal blending in Fig. 6 A～C softens is respectively 1.05,1.16 and 1.29.In addition, in Fig. 6 A～C, more than thick inertia the tissue more than 0.6mm existing in coal is divided into 0.6mm and lower than the size zoning 1 (i=1) of 1.5mm, more than 1.5mm and lower than the size zoning 2 (i=2) of 3mm, more than 3mm and lower than the size zoning 3 (i=3) of 5mm, more than 5mm and lower than the size zoning 4 (i=4) of 10mm and size zoning 5 (i=5) more than 10mm.Each mensuration coke surface in these 5 size zoning i is destroyed to powder rate DI ¹⁵⁰ _-6and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15, set the inertia of size zoning i and organize STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/).

In the present invention, the inertia of size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) be the value with respect to every 1% volume fraction of the inertia tissue existing in size zoning i.These degree of impact A _iand B _ithe condition of the space compactedness (Sv × Bd) when the coal that the loose density Bd when specific volume Sv when softening according to the coal by coal blending and coal pack into obtains softens changes.Therefore, for size zoning 1, to all size zoning i of size zoning m (i=1～m[natural number]), the coke surface based on following coke is destroyed powder rate DI ¹⁵⁰ _-6, the inertia that pre-determines size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/), under the space compactedness Sv × Bd when coal of the coal blending that the loose density Bd when specific volume Sv of described coke in the time that the coal by coal blending is softening packs into coal obtains softens, the dry distillation of coal of the inertia tissue that contains above-mentioned size zoning i is obtained.

Particularly, size zoning i (organize STRENGTH ON COKE table to draw and destroy powder rate DI by=1～inertia m) ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and size zoning i (=1～inertia m) is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) can obtain by utilizing method of least squares as shown in following formula (4) and (5) to carry out regression analysis.

DI ¹⁵⁰ _-6DI ¹⁵⁰ _-6(ref)＝∑ _i＝1～mA _i×Ib _i，j (4)

DI ¹⁵⁰ _6-15DI ¹⁵⁰ _6-15(ref)＝∑ _i＝1～mB _i×Ib _i，j (5)

Here Ib, _{i, j}for the size zoning i (content (volume %) of=1～inertia tissue m).

J is the kind that forms the feed coal of coal blending.DI ¹⁵⁰ _-6and DI ¹⁵⁰ _6-15respectively coke surface strength at break and coke volumetric fracture of rock intensity.As the DI in above-mentioned formula (4) and (5) ¹⁵⁰ _-6and DI ¹⁵⁰ _6-15, all use following value: to using the strength at break of coke of following coal blending manufacture to measure and the value that obtains, described coal blending is that (=1～mode m) is pulverized inertia tissue more than 0.6mm coordinate and forms by meeting size zoning i.

DI ¹⁵⁰ _-6and DI (ref) ¹⁵⁰ _6-15(ref) be respectively the coke volumetric fracture of rock intensity in the non-existent situation of impact of coke surface strength at break in the non-existent situation of impact of thick inertia tissue and thick inertia tissue.As the DI in above-mentioned formula (4) and (5) ¹⁵⁰ _-6and DI (ref) ¹⁵⁰ _6-15(ref), all use following value: to using the strength at break of coke of following coal blending manufacture to measure and the value that obtains, described coal blending be by thick inertia organize do not affect size (maximum length) that the mode of coke surface strength at break and coke volumetric fracture of rock intensity makes inertia tissue lower than 0.6mm pulverize and coordinate and form.

It is that 5 situation (m=5) can be obtained by utilizing the method for least squares shown in following formula (4 ') and (5 ') to carry out regression analysis that size zoning is counted m.

DI ¹⁵⁰ _-6DI ¹⁵⁰ _-6(ref)＝∑ _i＝1～5A _i×Ib _i，j (4′)

DI ¹⁵⁰ _6-15DI ¹⁵⁰ _6-15(ref)＝∑ _i＝1～5B _i×Ib _i，j (5′)

Here Ib, _{i, j}for example that 0.6mm is above and above and above and above and lower than the content (volume %) of the inertia tissue of the size zoning 4 (i=4) of 10mm and the such size zoning i (=1～5) of size zoning 5 (i=5) more than 10mm lower than size zoning 3 (i=3), the 5mm of 5mm lower than size zoning 2 (i=2), the 3mm of 3mm lower than size zoning 1 (i=1), the 1.5mm of 1.5mm.

For example, in the case of size zoning count m be 5 and the space compactedness (Sv × Bd) of coal when softening be 1.16, DI ¹⁵⁰ _-6and DI (ref) ¹⁵⁰ _6-15(ref) as shown in Fig. 4 B and Fig. 5 B, become respectively the 12.2 (DI of the coal blending of No.1～3 ¹⁵⁰ _-6) and the 1.3 (DI of the coal blending of No.1～4 ¹⁵⁰ _6-15).

In addition, the inertia that can confirm size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) separately with the content Ib of the inertia tissue of size zoning i _{i, j}additivity between (volume %) is set up.

In addition degree of impact A, _ithe volume % of (-/) and degree of impact B _ithe volume % of (-/) impact that is subject to because of the difference of the kind j of coal (=1～n[natural number]) is little, can confirm with the kind j of coal irrelevantly, is constant.

Therefore the coke surface that, is accompanied by the grinding particle size variation of the feed coal of kind j is destroyed powder rate DI ¹⁵⁰ _-6variation delta DI ¹⁵⁰ _-6and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15variation delta DI ¹⁵⁰ _6-15can be to be accompanied by the content Δ Ib of inertia tissue of the size zoning i that the grinding particle size of feed coal of kind j changes _{i, j}the measured value of (volume %), the inertia of size zoning i are organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) be basis, obtained by following formula (6) and (7).

ΔDI ¹⁵⁰ _-6(-)＝∑ _i＝1～mA _i×ΔIb _i，j (6)

ΔDI ¹⁵⁰ _6-15(-)＝∑ _i＝1～mB _i×ΔIb _i，j (7)

And then, use above-mentioned formula (2) by kind j (coke strenth variation delta DI when=1～feed coal n) is pulverized under prescribed condition ¹⁵⁰ ₁₅can be by shown in following formula (8).

ΔDI ¹⁵⁰ ₁₅(-)＝∑ _i＝1～mA _i×ΔIb _i，j+∑ _i＝1～mB _i×ΔIb _i，j (8)

Above-mentioned formula (8) is illustrated in and makes kind j (the coke strenth DI when grinding particle size of=1～feed coal n) changes ¹⁵⁰ ₁₅variation.Therefore, above-mentioned formula (8) if teaching by and degree of impact A _iand/or degree of impact B _ithe mode that the content (volume %) of the inertia tissue that large size zoning i is suitable reduces is pulverized feed coal, can effectively improve coke strenth DI ¹⁵⁰ ₁₅.

Basic technological thought of the present invention is to manufacture the coke with very high strength in the case of not causing the reduction that particle diameter is the increase of the dust coal below 0.3mm and the loose density of coal blending by the following method., the method is that the feed coal of multiple kinds is pulverized and coordinated by each kind, with coke strenth DI ¹⁵⁰ ₁₅become prescribed value (target value DI ¹⁵⁰ ₁₅(target)) above mode forms after coal blending, packs this coal blending into coke-fired furnace carry out destructive distillation and the method for manufacturing blast furnace coke.In the method, the condition of the space compactedness (Sv × Bd) when the coal that the loose density Bd when specific volume Sv while being softened by the coal of coal blending for basis and coal pack into obtains softens is carried out the coke that destructive distillation forms, and inertia the tissue more than 0.6mm that causes coke strenth to reduce is divided by size (maximum length).Organize degree of impact (degree of the impact A of matter on Coke Strength in the inertia of considering each size zoning _iand degree of impact B _i) basis on, feed coal is pulverized effectively.

Therefore, in the present invention, coke strenth DI ¹⁵⁰ ₁₅benchmark value DI ¹⁵⁰ ₁₅(ref) be made as the mode that becomes 70～85 quality % (the management standard granularity in common coke operation) by the accumulation ratio below particle diameter 3mm for all kinds each feed coal pulverized and coordinated the coke strenth (-) of the coal blending forming.In addition, as the particle diameter of feed coal, use screen aperture.

In addition, the content of thick inertia the tissue more than 1.5mm existing in feed coal 5～7 volume % are made as to cut off value, and the content that the feed coal of kind j that forms coal blending is divided into above-mentioned thick inertia tissue is that the content of the more than cut off value coal that contains high inertia and above-mentioned inertia tissue is lower than these 2 kinds, the coal that contains low dark decay of cut off value.And then the mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is pulverized the feed coal of the kind j ' that is divided into the coal that contains low dark decay.And the mode larger than the accumulation ratio below the particle diameter 3mm of the coal that contains low dark decay according to the accumulation ratio below particle diameter 3mm will be divided into the kind j of the coal that contains high inertia " feed coal pulverize.

About obtaining benchmark value DI ¹⁵⁰ ₁₅(ref) pulverization conditions of feed coal, for the feed coal of the kind j of all formation coal blendings, becomes described in the reasons are as follows that more than 70% mode determines according to the accumulation ratio below particle diameter 3mm.

Fig. 7 and Fig. 8 represent the relation of the cumulative volume ratio (volume %) of the coal (A coal) that contains high inertia and the accumulation ratio (quality %) below the particle diameter 3mm of the coal (B coal) that contains low dark decay and inertia tissue more than each size.

As shown in Figures 7 and 8, if the accumulation ratio below 3mm is lower than 70%, not only containing in the coal of high inertia (A coal), and containing in the coal of low dark decay (B coal), 10mm cumulative volume ratio above and more than 5mm very thick inertia tissue significantly rises.

These thick inertia tissues bring out the crackle from particle interface, and the strength at break of coke is significantly reduced.Therefore, solving coke strenth DI ¹⁵⁰ ₁₅benchmark value DI ¹⁵⁰ ₁₅(ref), in the pulverization conditions of feed coal, the mode that the feed coal of all kinds is become more than 70% by the accumulation ratio below particle diameter 3mm is pulverized.

About solving benchmark value DI ¹⁵⁰ ₁₅(ref) pulverization conditions of feed coal, for the feed coal of the kind j of all formation coal blendings, becomes described in the reasons are as follows that mode below 85% determines according to the accumulation ratio below particle diameter 3mm.

If the undersized of coal blending, the loose density in the time packing coal blending into coke-fired furnace reduces, and the interparticle space of coal increases.Therefore, the softening of coal and while expanding, coal is interparticle bondingly becomes insufficient, and coke strenth reduces.Therefore, solving coke strenth DI ¹⁵⁰ ₁₅benchmark value DI ¹⁵⁰ ₁₅(ref), in the pulverization conditions of feed coal, the mode that the feed coal of all kinds is become below 85% according to the accumulation ratio below particle diameter 3mm is pulverized.

On the other hand, the coal that division is contained to high inertia and the cut off value of the coal that contains low dark decay are set in by the content meter of inertia tissue described in the reasons are as follows in the scope of 5～7 volume %.

If this cut off value is divided by the content of the inertia tissue lower than 5 volume %, the less kind coal of the content of inertia tissue also becomes the object of strong pulverizing.As shown in Figure 8, even if the mode that the poor kind of inertia tissue exceedes common grinding particle size (the accumulation ratio below 3mm is 70～85 quality %) according to the accumulation ratio below 3mm is pulverized strongly, the reducing amount of the cumulative volume ratio of inertia tissue is also little.

Therefore, even coal is pulverized strongly, coke strenth also cannot improve, and only can cause the reduction that particle diameter is the increase of the dust coal below 0.3mm and the loose density of coal blending.

In addition,, if cut off value is divided by the content of the inertia tissue that exceedes 7 volume %, the coal of the more kind of the content of inertia tissue cannot become the object of strong pulverizing.Therefore, residual more inertia tissue in feed coal, thus cannot fully improve coke strenth.In addition, in order suitably to divide the coal that contains high inertia and the coal that contains low dark decay, based on the measured value of content (volume %) of thick inertia tissue with maximum length more than 1.5mm, the cut off value of the content of thick inertia tissue is suitably determined in the scope of 5～7 volume %.

Be divided into the kind j of the coal that contains high inertia " feed coal pulverize than the mode increasing by the accumulation ratio below particle diameter 3mm and the coal facies that contain low dark decay., the coal facies ratio with containing low dark decay, will contain the coal pulverizer of high inertia with high crush force.

Now, the kind j based on being divided into the coal that contains high inertia " feed coal in the inertia of the size zoning i that exists organize STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _i, the mode that the content (volume %) of the inertia tissue that the size zoning i large with degree of impact is suitable is reduced according to emphasis is pulverized feed coal.

Like this, by the content that forms kind 1 to the feed coal of all kinds of kind n (natural number) of coal blending and be divided into thick inertia tissue be the content of the more than cut off value coal that contains high inertia and thick inertia tissue lower than these 2 kinds, the coal that contains low dark decay of cut off value, corresponding to the pulverization conditions of divided feed coal, feed coal is pulverized.By the method, can not cause the reduction that particle diameter is the increase of the dust coal below 0.3mm and the loose density of coal blending, can manufacture the coke with high intensity.

In the present invention, in the time that the feed coal of the kind j working as with the coal that contains high inertia and the coal facies that contain low dark decay is pulverized and coordinated according to the mode that becomes grinding particle size separately, according to the mode that meets following formula (1x) or formula (1y), kind 1 to the feed coal of all kind j of kind n (natural number) forming after the pulverizing of coal blending is coordinated.This point is also feature of the present invention.

DI ¹⁵⁰ _-6(target)-DI ¹⁵⁰ _-6(ref)＝∑ _j＝1～n{∑ _i＝1～mA _i×(Ib _i，j-Ia _i，j)}×X _j (1x)

DI ¹⁵⁰ ₁₅(target)-DI ¹⁵⁰ ₁₅(ref)＝∑ _j＝1～n{∑ _i＝1～mA _i×(Ib _i，j-Ia _i，j)+∑ _i＝1～mB _i×(Ib _i，j-Ia _i，j)}×X _j (1y)

Wherein,

DI ¹⁵⁰ ₁₅(target), DI ¹⁵⁰ _-6(target): as the coke strenth (-) of target

DI ¹⁵⁰ ₁₅(ref), DI ¹⁵⁰ _-6(ref): the mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm for all kinds has been adjusted the granularity of feed coal the coke strenth (-) of the coal blending that cooperation forms

I (=1～m[natural number]): the size zoning (size of size zoning is measured by maximum length (mm)) of inertia tissue

J (=1～n[natural number]): the kind that forms the feed coal of coal blending

A _i: for the coke under the space compactedness Sv × Bd in the time that coal is softening, coal blending destructive distillation being obtained, the inertia of size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact (/ volume %)

B _i: for the coke under the space compactedness Sv × Bd in the time that coal is softening, coal blending destructive distillation being obtained, the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact (/ volume %)

Ib _{i, j}: the mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is adjusted granularity and is measured the content (volume %) of the inertia tissue of the size zoning i in the feed coal of the kind j obtaining

Ia _{i, j}: the mode that becomes 70～85 quality % at the accumulation ratio according to below particle diameter 3mm by the coal pulverizer that contains low dark decay and according to the accumulation ratio below particle diameter 3mm than the large mode of the accumulation ratio below the particle diameter 3mm of the coal that contains low dark decay by after the coal pulverizer that contains high inertia, the content (volume %) of the inertia tissue of the size zoning i in the feed coal of kind j

X _j: the mixing ratio (quality %) that forms the feed coal of the kind j of coal blending

In addition, the content Ib of the inertia tissue below 3mm _{i, j}many.Therefore, even at degree of the impact A of inertia tissue _iin little situation, preferably the inertia tissue below 3mm is divided into 2 above size zonings.In addition degree of the impact A of inertia tissue more than 3mm, _iand degree of impact B _igreatly.Therefore, even at content Ib _{i, j}in few situation, preferably inertia tissue more than 3mm is divided into 2 above size zonings.

Particularly consider efficiency aspect, the size zoning i of inertia tissue (=1～m[natural number]) preferably counts m by size zoning and is made as 5, and according to become 0.6mm above and lower than size zoning 1, the 1.5mm of 1.5mm above and lower than size zoning 2, the 3mm of 3mm above and lower than the size zoning 3 of 5mm, 5mm is above and divide lower than the mode of the size zoning 4 of 10mm and size zoning 5 more than 10mm.

First, above-mentioned formula (1y) is described.Above-mentioned formula (1y) is according to derivation as described below: will be by mixing ratio X in above-mentioned formula (8) _jthe coke strenth variable quantity of the feed coal of the kind j that (quality %) coordinates sums up and derives for all kinds.In addition, above-mentioned formula (1y) is for determining coke strenth (DI ¹⁵⁰ ₁₅) from the benchmark value (DI of coke strenth ¹⁵⁰ ₁₅(ref)) bring up to the target value (DI of coke strenth ¹⁵⁰ ₁₅(target) pulverization conditions)., determine that the mode that becomes 70～85 quality % with respect to the accumulation ratio by below particle diameter 3mm is adjusted granularity and the content Ib of the inertia tissue of size zoning i in the feed coal of the kind j that measures _{i, j}, make the content Ia of the inertia tissue of the size zoning i in the feed coal of kind j after pulverizing _{i, j}with which kind of degree change and just can.

In addition, in order to set the benchmark value of content, the mode that becomes 70～85 quality % for the accumulation ratio by below particle diameter 3mm has in advance been adjusted the feed coal of the kind 1 of granularity to all kind j of kind n (=1～n[natural number]), measures the content (volume %) of the thick inertia tissue with maximum length more than 1.5mm and above-mentioned size zoning 1 to above-mentioned size field and draw the content Ib of the inertia tissue of all size zoning i of m _{i, j}(volume %).And then, for the feed coal of all kind j of the above-mentioned kind 1 to above-mentioned kind n after pulverizing, measure above-mentioned size zoning 1 to above-mentioned size field and draw the content Ia of the inertia tissue of all size zoning i of m _{i, j}(volume %).

In addition, at the feed coal of kind j respectively with the mixing ratio X of regulation _j(quality %) coordinates in the coal blending forming, as described in above-mentioned formula (1y), and the coke strenth DI of the feed coal of known kind j ¹⁵⁰ ₁₅mixing ratio X with the feed coal of kind j _jbetween additivity set up.

In addition, in above-mentioned formula (1y), the target value (DI of coke strenth ¹⁵⁰ ₁₅(target)) set according to the requirement of the quality of the productivity of coke-fired furnace and blast furnace coke.In addition, as mentioned above, the benchmark value (DI of coke strenth ¹⁵⁰ ₁₅(ref)) be made as the coke strenth (-) that becomes the mode of 70～85 quality % for all kinds according to the accumulation ratio below particle diameter 3mm feed coal is separately pulverized and coordinated the coal blending forming.

In the present invention, the target value (DI of coke strenth ¹⁵⁰ ₁₅(target)) be not particularly limited.The inventive example is as by the target value (DI of coke strenth ¹⁵⁰ ₁₅(target)) be made as in the situation more than 86 and then more than 87, the particle diameter that can suppress to accompany with the strong pulverizing of the coal that contains inertia tissue is the reduction of the increase of the dust coal below 0.3mm and the loose density of coal blending entirety, can stablize and effectively improve coke strenth.

Then, above-mentioned formula (1x) is described.As shown in Figure 6, the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/)) organize STRENGTH ON COKE surface breakdown powder rate DI than the inertia of size zoning i ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) little, therefore, can be by above-mentioned degree of impact B _ithe volume % of (-/)) be made as approx zero.

In above-mentioned formula (1x) due to degree of impact B _ilittle, therefore in above-mentioned formula (1y), by ∑ _i=1～mb _i× (Ib _{i, j}-Ia _{i, j}) be made as 0.In addition,, owing to can ignoring the impact of volumetric fracture of rock of coke, therefore the target value of coke strenth and benchmark value are made as respectively to DI ¹⁵⁰ _-6(target), DI ¹⁵⁰ _-6(ref).

Embodiment

Use can be simulated the test coke-fired furnace of physical device coke-fired furnace, uses the coal (A coal, B coal) of 2 kinds shown in table 1, implements the retort experiment of coal and the evaluation test of coke.

Table 1

The loose density Bd of coal measures by the method for recording in ASTM D-291-86, is adjusted to the loose density of mensuration, packs coal into coke-fired furnace.

In addition, the swelling property testing apparatus of the dilatometer of the specific volume Sv when overall expansion rate TD of coal and coal softening by having utilized JIS M8801 is measured.In addition, the specific volume Sv (cm when overall expansion rate TD (%) of coal is softening with coal ³/ g) be encased in coal Intake Quantity w (g) in dilatometer and have the relation of following formula (9) by use.

Sv＝0.96π×(1+TD/100)/w (9)

The average reflectance R of coal ₀be made as the weighted mean of the average maximum reflectivity of the vitrinite that the method recorded in micro organization's composition of the coal by JIS M8816 and method for measuring reflectance measures.

Maximum length is that content (volume %) TI of thick inertia tissue more than 1.5mm measures by the following method.,, using as the coal destructive distillation of determination object and imbed resin in the cut surface of the coke obtaining, after this cut surface is ground, use microscope photographing photo.Inertia tissue in the photo of this cut surface is carried out to mark, use image analysis software to measure size (maximum length) and the area occupation ratio (area %) thereof of inertia tissue.By these measured values, the size zoning of each inertia tissue is obtained to the volume fraction (volume %) of inertia tissue.Calculated accumulation ratio (content) TI (for example, with reference to patent documentation 3) that counts thick inertia tissue more than 1.5mm with maximum length by these volume fractions (volume %).

First the mode that, the A coal shown in table 1 and B coal is become to 83 quality % with the accumulation ratio below particle diameter 3mm is pulverized.In addition, above and above and above and above and divide inertia tissue lower than the mode of the size zoning 4 of 10mm, more than 10mm size zoning 5 according to size (maximum length) lower than size zoning 3, the 5mm of 5mm lower than size zoning 2, the 3mm of 3mm lower than size zoning 1, the 1.5mm of 1.5mm according to becoming 0.6mm.For A coal and the each content Ib that measures the inertia tissue that belongs to these size zonings of B coal _{i, j}(volume %), and calculate the content that maximum length is thick inertia tissue more than 1.5mm (volume %).The results are shown in table 2.

Then the mode that, the accumulation ratio with below particle diameter 3mm is become to 83 quality % has been carried out the A coal as shown in table 2 pulverized and B coal by (the A coal: B coal=50: 50 and A coal: B coal=65: 30) coordinate of the fit rate shown in table 3 and table 5.And then, as shown in table 4 and table 6, in coal blending, add 5% or 2% moisture, the loose density Bd of coal is adjusted to 0.75t/m ³or 0.83t/m ³, pack in coke-fired furnace, carry out destructive distillation and manufacture coke.

Table 3

^*1,2 top represents the ratio Ia of the inertia tissue after pulverizing _ij, below represents the Ia of top _ijratio Ib with the inertia tissue shown in table 2 _ijdifference Δ Ib _ij.

Table 5

^*1,2 top represents the ratio Ia of the inertia tissue after pulverizing _ij, below represents the Ia of top _ijratio Ib with the inertia tissue shown in table 2 _ijdifference Δ Ib _ij.

Specific volume Sv when specific volume Sv when coal blending charcoal shown in table 4 and table 6 softening uses following formula (10) by the A coal shown in inertia factor IF, table 2 and B coal softening _aand Sv _b, and the fit rate X of A coal and B coal _a(-) and X _b(-) obtains.

Here, inertia factor IF (-) is the swelling property inhibition index of the coal blending that caused lower than the low coal carbonization degree coal (being equivalent to the B coal in table 1) of 470 DEG C by solidification value more contained in coal blending.This index is used the fit rate X of low coal carbonization degree charcoal as shown in TOHKEMY 2005-194358 communique _l(-) defined by following formula (11).

Sv＝(Sv _A×IF)×X _A+Sv _B×X _B (10)

IF＝-0.004×X _L×100+1.00 (11)

In addition, low coal carbonization degree coal is again solidification value lower than the coal of 470 DEG C, is equivalent to B coal in table 1.,, in the present embodiment and comparative example, in above-mentioned formula (11), inertia factor IF can pass through the fit rate X of low coal carbonization degree coal _lbe replaced as the fit rate X of B coal _bcalculate.

For the index when coal blending is pulverized, the inertia of size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning i organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/) carry out destructive distillation under the condition of space compactedness (Sv × Bd) based in the time that the coal shown in table 4 and table 6 is softening and the coke surface of the coke that obtains is destroyed powder rate DI ¹⁵⁰ _-6and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15, press in advance shown in table 7 and table 8 and determine.

Table 7

Table 8

For example, in the embodiment 1 of table 4, specific volume Sv when coal blending charcoal softening is 1.40 (cm ³/ g), space compactedness Sv × Bd when coal blending charcoal softening is 1.05 (-).In addition the benchmark value DI of coke strenth, ¹⁵⁰ ₁₅(ref) be 85.8.

In embodiment 1～5, by the target value DI of coke strenth ¹⁵⁰ ₁₅set by shown in table 3 and table 4, will be set as 6% for dividing the cut off value that the coal that contains high inertia and the maximum length of the coal that contains low dark decay are the content (volume %) of thick inertia tissue more than 1.5mm.Therefore, as shown in table 2, maximum length is that the content (volume %) of thick inertia tissue more than 1.5mm is greater than 6% A coal and is divided into the coal that contains high inertia.Equally, maximum length is that the content (volume %) of thick inertia tissue more than 1.5mm is less than 6% B coal and is divided into the coal that contains low dark decay.

In embodiment 1～5, as shown in table 3 and table 4, be that the mode of the particle below 3mm is by B coal pulverizer according to the particle diameter that contains 73% or 70%.Equally, as shown in table 3 and table 4, be that the mode of the particle below 3mm is by A coal pulverizer by the granularity that contains 93% or 90%.And then the inertia based on size zoning 1～5 is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _ithe volume % of (-/) and the inertia of size zoning 1～5 organize STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _ithe volume % of (-/), according to the mode that meets above-mentioned formula (1y), A coal is coordinated with B coal.

In embodiment 1～5, according to the present invention, coal blending pulverized and coordinate, therefore making the content of the micro mist below the 0.3mm of the reason that becomes airborne dust not increase in coal blending, and, loose density when coke-fired furnace packs into also can not reduce, and has realized the target value DI of more than 86.5 coke strenths ¹⁵⁰ ₁₅(target).

In comparative example 1, similarly to Example 2 by the target value DI of coke strenth ¹⁵⁰ ₁₅(target) be made as 86.5, by the coke strenth variation delta DI improving by pulverizing ¹⁵⁰ ₁₅be made as 0.7.To be set as 3% for dividing the cut off value that the coal that contains high inertia and the maximum length of the coal that contains low dark decay are the content (volume %) of thick inertia tissue more than 1.5mm.This cut off value is lower than cut off value of the present invention (5～7 volume %).

And then, as disclosed in Fig. 2 of patent documentation 3, be that more than 1.5mm thick inertia tissue is to DI by maximum length ¹⁵⁰ ₁₅degree of impact be set as 0.15 (/ volume %).According to patent documentation 3, in order to obtain the coke strenth variation delta DI as target ¹⁵⁰ ₁₅, the benchmark value Z ' (being the content of inertia tissue more than 1.5mm as the maximum length of target) that is the content of inertia tissue more than 1.5mm using maximum length is made as 1.80 (volume %).Δ DI ¹⁵⁰ ₁₅be thought of as 0.15 × (6.44-1.80)=0.70 (the 6.44th, the weighted mean of the data of the A coal shown in table 2 and the data of B coal).In fact, the mode that according to the granularity that contains 95 quality % and 90 quality % is the particle below 3mm is pulverized A coal and B coal respectively, and, the content (volume %) that is thick inertia tissue more than 1.5mm according to maximum length becomes below 1.80% of benchmark value, and (coal blending is 1.74%, A coal is that 1.56%, B coal is 1.93%) mode pulverize.

Consequently, becoming particle diameter in the coal blending of reason of airborne dust is that the content (volume %) of the dust coal below 0.3mm is increased to 30.0%.In addition loose density Bd when, coke packs into is reduced to 0.70t/m ³, coke strenth DI ¹⁵⁰ ₁₅be 86.2, cannot reach target value DI ¹⁵⁰ ₁₅(target) 86.5.

In comparative example 2, use the sorting technique of disclosed coal in patent documentation 1, the mode that is the particle below 3mm according to the granularity that contains 73 quality % by the A coal (TI < 35%) that is equivalent to the coal that contains low dark decay is pulverized, and will be equivalent to the B coal (R of non-micro-caking coal ₀≤ 0.9%) mode that is the particle below 3mm according to the granularity that contains 93 quality % is pulverized.

The loose density Bd of coal blending when consequently, coke-fired furnace packs into and embodiment 1 and 2 similarly become 0.75t/m ³, the content that becomes particle diameter in the coal blending of reason of airborne dust and be the dust coal below 0.3mm does not also increase.But, coke strenth DI ¹⁵⁰ ₁₅become 85.8, lower than the coke strenth of embodiment 1 and 2.

In comparative example 3, by the target value DI of coke strenth ¹⁵⁰ ₁₅(target) be set as similarly to Example 3 87.0, by the coke strenth variation delta DI improving by pulverizing ¹⁵⁰ ₁₅be set as 0.5.To be set as 3% for dividing the cut off value that the coal that contains high inertia and the maximum length of the coal that contains low dark decay are the content (volume %) of thick inertia tissue more than 1.5mm.This cut off value is lower than cut off value of the present invention (5～7 volume %).

And then, as disclosed in Fig. 2 of patent documentation 3, be that more than 1.5mm thick inertia tissue is to DI by maximum length ¹⁵⁰ ₁₅degree of impact be set as 0.15 (/ volume %).According to patent documentation 3, in order to obtain the coke strenth variation delta DI as target ¹⁵⁰ ₁₅, the benchmark value Z ' (being the content of inertia tissue more than 1.5mm as the maximum length of target) that is the content of inertia tissue more than 1.5mm using maximum length is made as 3.10 (volume %).Δ DI ¹⁵⁰ ₁₅be envisioned for 0.15 × (6.44-3.10)=0.50 (the 6.44th, the weighted mean of the data of the A coal shown in table 2 and the data of B coal).In fact, the mode that according to the granularity that contains 94 quality % and 84 quality % is the particle below 3mm is pulverized A coal and B coal respectively, and, the content (volume %) that is thick inertia tissue more than 1.5mm according to maximum length is that (coal blending is 2.84% to below 3.10% of benchmark value, A coal is that 2.69%, B coal is 2.99%) mode pulverize.

Consequently, in comparative example 3, compare with embodiment 3, the content that becomes particle diameter in the coal blending of reason of airborne dust and be the dust coal below 0.3mm increases, and loose density Bd when coke-fired furnace packs into also reduces.Therefore, coke strenth DI ¹⁵⁰ ₁₅cannot reach target value DI ¹⁵⁰ ₁₅(target) 87.0, reduction compared with the coke strenth of embodiment 3.

In comparative example 4, use the sorting technique of disclosed coal in patent documentation 1, the mode that is the particle below 3mm according to the granularity that contains 73 quality % by the A coal (TI < 35%) that is equivalent to the coal that contains low dark decay is pulverized, and will be equivalent to the B coal (R of non-micro-caking coal ₀≤ 0.9%) mode that is the particle below 3mm according to the granularity that contains 93 quality % is pulverized.

The loose density Bd of coal blending when consequently, coke-fired furnace packs into becomes 0.83t/m similarly to Example 3 ³, the content that becomes particle diameter in the coal blending of reason of airborne dust and be the dust coal below 0.3mm does not also increase.But, coke strenth DI ¹⁵⁰ ₁₅become 86.4, reduction compared with the coke strenth of embodiment 3.

In comparative example 5, by the target value DI of coke strenth ¹⁵⁰ ₁₅(target) be set as similarly to Example 4 86.8, by the coke strenth variation delta DI improving by pulverizing ¹⁵⁰ ₁₅be made as 0.3.

And then, as disclosed in Fig. 2 of patent documentation 3, be that more than 1.5mm thick inertia tissue is to DI by maximum length ¹⁵⁰ ₁₅degree of impact be set as 0.15 (/ volume %).According to patent documentation 3, in order to obtain the coke strenth variation delta DI as target ¹⁵⁰ ₁₅, the benchmark value Z ' (being the content of inertia tissue more than 1.5mm as the maximum length of target) that is the content of inertia tissue more than 1.5mm using maximum length is made as 5.41 (volume %).Δ DI ¹⁵⁰ ₁₅be envisioned for 0.15 × (7.41-5.41)=0.50 (the 7.41st, the weighted mean of the data of the A coal shown in table 2 and the data of B coal).In fact, the mode that according to the granularity that contains 91 quality % and 83 quality % is the particle below 3mm is pulverized A coal and B coal respectively, and, the content (volume %) that is thick inertia tissue more than 1.5mm according to maximum length becomes below 5.41% of benchmark value, and (coal blending is 5.31%, A coal is that 6.45%, B coal is 3.20%) mode pulverize.

Consequently, becoming particle diameter in the coal blending of reason of airborne dust is that the content (volume %) of the dust coal below 0.3mm is increased to 26.0%.In addition loose density Bd when, coke packs into is reduced to 0.73t/m ³, coke strenth DI ¹⁵⁰ ₁₅be 86.6, than target value DI ¹⁵⁰ ₁₅(target) 86.8 low.

In comparative example 6, use the sorting technique of disclosed coal in patent documentation 1, the mode that is the particle below 3mm according to the granularity that contains 78 quality % by the A coal (TI < 35%) that is equivalent to the coal that contains low dark decay is pulverized, and will be equivalent to the B coal (R of non-micro-caking coal ₀≤ 0.9%) mode that is the particle below 3mm according to the granularity that contains 93 quality % is pulverized.

Consequently, similarly to Example 4, loose density Bd becomes 0.75t/m to coal blending when coke-fired furnace packs into ³, the content that becomes particle diameter in the coal blending of reason of airborne dust and be the dust coal below 0.3mm does not also increase.But, coke strenth DI ¹⁵⁰ ₁₅become 86.5, reduction compared with the coke strenth of embodiment 4.

In comparative example 7, by the target value DI of coke strenth ¹⁵⁰ ₁₅(target) be made as similarly to Example 5 87.2, by the coke strenth variation delta DI improving by pulverizing ¹⁵⁰ ₁₅be set as 0.2.

And then, as disclosed in Fig. 2 of patent documentation 3, be that more than 1.5mm thick inertia tissue is to DI by maximum length ¹⁵⁰ ₁₅degree of impact be set as 0.15 (/ volume %).According to patent documentation 3, in order to obtain the coke strenth variation delta DI as target ¹⁵⁰ ₁₅, the benchmark value Z ' (being the content of inertia tissue more than 1.5mm as the maximum length of target) that is the content of inertia tissue more than 1.5mm using maximum length is made as 6.07 (volume %).Δ DI ¹⁵⁰ ₁₅be envisioned for 0.15 × (7.41-6.07)=0.20 (the 7.41st, the weighted mean of the data of the A coal shown in table 2 and the data of B coal).In fact, the mode that according to the granularity that contains 90 quality % and 83 quality % is the particle below 3mm is pulverized A coal and B coal respectively, and the content (volume %) that is thick inertia tissue more than 1.5mm according to maximum length becomes below 6.07% of benchmark value, and (coal blending is 5.83%, A coal is that 7.25%, B coal is 3.20%) mode pulverize.

Consequently, the content (volume %) that becomes granularity in the coal blending of reason of airborne dust and be the dust coal below 0.3mm is increased to 26.0%, and the loose density Bd of coke while packing into is also reduced to 0.81t/m ³.Therefore, coke strenth DI ¹⁵⁰ ₁₅miss the mark value DI ¹⁵⁰ ₁₅(target) 87.2.

In comparative example 8, use the sorting technique of disclosed coal in patent documentation 1, the mode that is the particle below 3mm according to the granularity that contains 78 quality % by the A coal (TI < 35%) that is equivalent to the coal that contains low dark decay is pulverized, and will be equivalent to the B coal (R of non-micro-caking coal ₀≤ 0.9%) mode that is the particle below 3mm according to the granularity that contains 93 quality % is pulverized.

The loose density Bd of coal blending when consequently, coke-fired furnace packs into is 0.83t/m similarly to Example 5 ³, the content that becomes particle diameter in the coal blending of reason of airborne dust and be the dust coal below 0.3mm does not also increase.But, coke strenth DI ¹⁵⁰ ₁₅become 86.9, lower than the coke strenth of embodiment 5.

The industrial possibility of utilizing

According to the present invention, by effectively coal being pulverized, can not cause the reduction that particle diameter is the increase of the dust coal below 0.3mm and the loose density of coal blending, can manufacture the coke with very high strength.In addition,, according to the present invention, even if improve the usage rate of cheap and inferior non-micro-caking coal, also can manufacture the coke of high strength and homogeneous.Therefore, the present invention utilizes possibility high in coke process industry.

Claims (3)

1. a manufacture method for blast furnace coke, it packs coal blending in coke-fired furnace into, and described coal blending is the feed coal of multiple kinds to be pulverized and coordinated by each kind form, it is characterized in that,

(A) (A1) be that more than 0.6mm inertia tissue is divided into according to maximum length the size zoning that size zoning 1 is m to the size zoning number of size zoning m by maximum length;

(A2) all size zoning i to described size zoning m for described size zoning 1, the coke surface based on coke is destroyed powder rate DI ¹⁵⁰ _-6, the inertia that pre-determines size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iunder space compactedness Sv × Bd when the coal of the described coal blending that the loose density Bd when specific volume Sv of described coke in the time that the coal by described coal blending is softening packs into coal obtains softens, the coal destructive distillation of the inertia tissue that contains described size zoning i is obtained, wherein, i is the natural number of 1～m, described degree of impact A _iunit be-/volume %,

The inertia of described size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iobtain by utilizing the method for least squares shown in following formula (4) to carry out regression analysis,

DI ¹⁵⁰ _-6-DI ¹⁵⁰ _-6(ref)=Σ _i=1～mA _i×Ib _i,j (4)

Here Ib, _i,jfor the content of the inertia tissue of size zoning i, Ib _i,junit be volume %,

J is the kind that forms the feed coal of coal blending,

Described DI ¹⁵⁰ _-6for utilizing tumbler test machine that JIS K2151 specifies to using the coke of following coal blending manufacture to carry out the ratio of 150 6mm screen underflows after whirl test, described coal blending is by the mode that meets size zoning i, inertia tissue more than 0.6mm to be pulverized and coordinated to form;

(B) mode that (B1) becomes 70～85 quality % for the accumulation ratio according to below particle diameter 3mm has been carried out the kind 1 the adjusted feed coal to all kind j of kind n to granularity, measure the content of the thick inertia tissue with maximum length more than 1.5mm and the described size zoning 1 content Ib to the inertia tissue of all size zoning i of described size zoning m _i,j, the natural number that wherein j is 1～n, the content Ib of the content of described thick inertia tissue and inertia tissue _i,junit be volume %;

(B2) measured value of the content based on described thick inertia tissue, is set in the cut off value of the content of described thick inertia tissue in the scope of 5～7 volume %;

(C) content that (C1) feed coal of all kind j of described kind 1 to described kind n is divided into described thick inertia tissue is that the content of the more than described cut off value coal that contains high inertia and described thick inertia tissue is lower than these 2 kinds, the coal that contains low dark decay of described cut off value;

(C2) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is pulverized the feed coal of the kind of the coal that contains low dark decay described in being divided into;

(C3) according to accumulation ratio below particle diameter 3mm than described in contain low dark decay the particle diameter 3mm of coal below the large mode of accumulation ratio, the feed coal of the kind of the coal that contains high inertia described in being divided into is pulverized;

(C4) for the feed coal of all kind j of the described kind 1 to described kind n after pulverizing, measure the content Ia of described size zoning 1 to the inertia tissue of all size zoning i of described size zoning m _i,j, the content Ia of described inertia tissue _i,junit be volume %;

(D) at DI ¹⁵⁰ _-6(target) be target value, the DI of coke strenth ¹⁵⁰ _-6(ref) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm for all kind j for described kind 1 to described kind n adjusts and coordinates coke strenth, the X of the coal blending obtaining to the granularity of feed coal _jfor forming in the situation of mixing ratio of feed coal of kind j of coal blending, according to meeting DI ¹⁵⁰ _-6(target)-DI ¹⁵⁰ _-6(ref)=Σ _j=1～n{ Σ _i=1～ma _i× (Ib _i,j-Ia _i,j) × X _jthe feed coal of all kind j of the described kind 1 to described kind n of mode after to described pulverizing coordinate, the target value of described coke strenth is zero dimension.

2. a manufacture method for blast furnace coke, it packs coal blending in coke-fired furnace into, and described coal blending is the feed coal of multiple kinds to be pulverized and coordinated by each kind form, it is characterized in that,

(A) (A1) be that more than 0.6mm inertia tissue is divided into according to maximum length the size zoning that size zoning 1 is m to the size zoning number of size zoning m by maximum length;

(A2) all size zoning i to described size zoning m for described size zoning 1, the coke surface based on coke is destroyed powder rate DI ¹⁵⁰ _-6and coke volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15, the inertia that pre-determines size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _iunder space compactedness Sv × Bd when the coal of the described coal blending that the loose density Bd when specific volume Sv of described coke in the time that the coal by described coal blending is softening packs into coal obtains softens, the coal destructive distillation of the inertia tissue that contains described size zoning i is obtained, the natural number that wherein i is 1～m, described degree of impact A _iand B _iunit be-/volume %,

The inertia of described size zoning i is organized STRENGTH ON COKE surface breakdown powder rate DI ¹⁵⁰ _-6degree of impact A _iand the inertia of described size zoning i is organized STRENGTH ON COKE volumetric fracture of rock powder rate DI ¹⁵⁰ _6-15degree of impact B _iobtain by utilizing the method for least squares shown in following formula (4) and (5) to carry out regression analysis,

DI ¹⁵⁰ _-6-DI ¹⁵⁰ _-6(ref)=Σ _i=1～mA _i×Ib _i,j (4)

DI ¹⁵⁰ _6-15-DI ¹⁵⁰ _6-15(ref)=Σ _i=1～mB _i×Ib _i,j (5)

Here Ib, _i,jfor the content of the inertia tissue of size zoning i, Ib _i,junit be volume %,

J is the kind that forms the feed coal of coal blending,

Described DI ¹⁵⁰ _-6for utilizing tumbler test machine that JIS K2151 specifies to using the coke of following coal blending manufacture to carry out the ratio of 150 6mm screen underflows after whirl test, described DI ¹⁵⁰ _6-15for utilizing tumbler test machine that JIS K2151 specifies to using the coke of following coal blending manufacture to carry out 150 6mm screen overflows after whirl test and the ratio of 15mm screen underflow, described coal blending is by the mode that meets size zoning i, inertia tissue more than 0.6mm to be pulverized and coordinated to form;

(B) mode that (B1) becomes 70～85 quality % for the accumulation ratio according to below particle diameter 3mm has been carried out the kind 1 the adjusted feed coal to all kind j of kind n to granularity, measure the content of the thick inertia tissue with maximum length more than 1.5mm and the described size zoning 1 content Ib to the inertia tissue of all size zoning i of described size zoning m _i,j, wherein, the natural number that j is 1～n, the content Ib of the content of described thick inertia tissue and inertia tissue _i,junit be volume %;

(B2) measured value of the content based on described thick inertia tissue, is set in the cut off value of the content of described thick inertia tissue in the scope of 5～7 volume %;

(C) content that (C1) feed coal of all kind j of described kind 1 to described kind n is divided into described thick inertia tissue is that the content of the more than described cut off value coal that contains high inertia and described thick inertia tissue is lower than these 2 kinds, the coal that contains low dark decay of described cut off value;

(C2) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm is pulverized the feed coal of the kind of the coal that contains low dark decay described in being divided into;

(C3) according to accumulation ratio below particle diameter 3mm than described in contain low dark decay the particle diameter 3mm of coal below the large mode of accumulation ratio, the feed coal of the kind of the coal that contains high inertia described in being divided into is pulverized;

(C4) for the feed coal of all kind j of the described kind 1 to described kind n after pulverizing, measure the content Ia of described size zoning 1 to the inertia tissue of all size zoning i of described size zoning m _i,j, the content Ia of described inertia tissue _i,junit be volume %;

(D) at DI ¹⁵⁰ ₁₅(target) be target value, the DI of coke strenth ¹⁵⁰ ₁₅(ref) mode that becomes 70～85 quality % according to the accumulation ratio below particle diameter 3mm for all kind j for described kind 1 to described kind n adjusts and coordinates coke strenth, the X of the coal blending obtaining to the granularity of feed coal _jfor forming in the situation of mixing ratio of feed coal of kind j of coal blending, according to meeting DI ¹⁵⁰ ₁₅(target)-DI ¹⁵⁰ ₁₅(ref)=Σ _j=1～n{ Σ _i=1～ma _i× (Ib _i,j-Ia _i,j)+Σ _i=1～mb _i× (Ib _i,j-Ia _i,j) × X _jthe feed coal of all kind j of the described kind 1 to described kind n of mode after to described pulverizing coordinate, the target value of described coke strenth is zero dimension.

3. the manufacture method of blast furnace coke according to claim 1 and 2, it is characterized in that, described size zoning is divided in the following manner: size zoning is counted to m and be made as 5, more than being divided into 0.6mm and lower than the size zoning 1 of 1.5mm, being more than i=1,1.5mm and being to be more than i=3,5mm and to be that i=4 and size zoning 5 more than 10mm are i=5 lower than the size zoning 4 of 10mm more than i=2,3mm and lower than the size zoning 3 of 5mm lower than the size zoning 2 of 3mm.