CA1063060A - Manufacturing formed coke - Google Patents
Manufacturing formed cokeInfo
- Publication number
- CA1063060A CA1063060A CA248,526A CA248526A CA1063060A CA 1063060 A CA1063060 A CA 1063060A CA 248526 A CA248526 A CA 248526A CA 1063060 A CA1063060 A CA 1063060A
- Authority
- CA
- Canada
- Prior art keywords
- coal
- coke
- oven battery
- agglomeration
- coke oven
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
- C10B53/08—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form in the form of briquettes, lumps and the like
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L5/00—Solid fuels
- C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
- C10L5/04—Raw material of mineral origin to be used; Pretreatment thereof
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Materials Engineering (AREA)
- Coke Industry (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improvement is provided in a method for manufacturing a high-strength formed coke in a slight mutual agglomeration solely from formed coal in a conventional horizontal type coke oven battery, which includes the steps of sieving a plurality of different types of raw material coal fines to a size not exceeding 1.5 mm., fixing such plurality of different types of raw material coal fines thus sieved with a binder, forming that mixture to produce a formed coal.
charging only that formed coal into the coke oven battery, and then carbonizing the formed coal in the coke oven battery under conventional carbonizing conditions to produce a formed coke.
The improvement resides in blending the plurality of different types of coal fines after said sieving step to form a mixture of coal fines so as to satisfy the following conditions:
(a) AP index: 75 at the minimum, (b) Mean maximum reflectance:
1.20% at the minimum, and (e) A [dilatation] - [contraction] value of fro -2% to +5% when carbonized under conventional conditions in the coke oven battery at a heating rate of 5°C./min. (350 - 600°C.). In this way, an improved high-strength formed coke having a percentage of co-agglomeration within the range of from 40 to 90% is provided, which is especially useful in blast furnaces.
An improvement is provided in a method for manufacturing a high-strength formed coke in a slight mutual agglomeration solely from formed coal in a conventional horizontal type coke oven battery, which includes the steps of sieving a plurality of different types of raw material coal fines to a size not exceeding 1.5 mm., fixing such plurality of different types of raw material coal fines thus sieved with a binder, forming that mixture to produce a formed coal.
charging only that formed coal into the coke oven battery, and then carbonizing the formed coal in the coke oven battery under conventional carbonizing conditions to produce a formed coke.
The improvement resides in blending the plurality of different types of coal fines after said sieving step to form a mixture of coal fines so as to satisfy the following conditions:
(a) AP index: 75 at the minimum, (b) Mean maximum reflectance:
1.20% at the minimum, and (e) A [dilatation] - [contraction] value of fro -2% to +5% when carbonized under conventional conditions in the coke oven battery at a heating rate of 5°C./min. (350 - 600°C.). In this way, an improved high-strength formed coke having a percentage of co-agglomeration within the range of from 40 to 90% is provided, which is especially useful in blast furnaces.
Description
The present inyention rel~tes to an improvement in the method for manu~acturing a high-strength formed coke in a slight mutual agglomeration using a horizontal slot type coke oven battery, such coke being especially useful for blast furnaces.
A method is now known for the purpose of improving the coke quality and the productivity, in manufacturing a coke for blast furnace using a conventional, i.e., a horizontal slot type coke oven battery.
Such known method comprises charging briquettes produced by forming r blended raw material coal fines by a compression forming machine (herein-after referred to as "~ormed coal"), into the horizontal slot-type coke oven battery thus carbonizing the formed coal to produce a coke~
According to this method, a coke which is especially useful in a blast furnace is produced either by charging a formed coal and coal fines after r mixing into a horizontal slot type coke oven battery, charging a formed coal and coal fines alternately in horizontal layers into a horizontal slot type coke i oven battery, or charging a formed coal only into a horizontal slot type coke _ oven battery; and then carbonizing the raw materials thus charged. ~
~' In the aforementioned method, in charging a formea coal and coal fines in combination into a horizontal slot type coke oven battery, pieces of formed coal should be completely agglomerated with surrounding coal fines during the process of carbonizatian. For this purpose, it is necessary to use raw material coals having a somewhat high fluidity in carbonizing, and this not only imposes certain limits on the range of selection and blending of raw materiaI coals used. but also necessitates troublesom charging practices into the horizontal slot type .
coke oven battery.
When only a formed coal is charged into a horizontal slot type coke oven battery, wide range of selection and blending of raw materlal coals uaed, i~ available and the charging into a horizontal slot type coke oven battery i8 also easy. In this case, however, the operation of the horizontal slot type coke oven battery is problematic.
~ ' .
. .
More specific~lly? ~ith ~ ~iew to facilltat~ng discharge of an already carbonized for~ed coal ~hereinafter referred to ~s "formed coke~, it is necessary that pieces of ~ormed coke should be mutually agglomerated.
On the other hand, however, a formed coke mutually aggiomerated too firmly remains in the agglomerated state even after discharging, and is not separated into pieces, It is therefore desirable that a formed coke produced by chargIng only a formed coal into a horizontal slot type coke oven battery, being in a ~utually agglomerated state at the time of discharging, should 6e only slightly agglomerated so as to permit easy separation into pieces after discharging. In a horizontal slot type coke oven battery, however, the heating rate differs between the zone near the oven walls and the central zone. If the blend~ng ratio of raw material coals is decided on the basis of the central zone, pleces of formed coke in the zone near the oven walls are mutuahly agglomerated too firmly, and remain in the agglomerated state even after discharging, not permitting separation into pieces, A blending ratio of raw material coals not causing mutual agglomeration of a formed coke, if adopted to avoid the aforementioned drawback, leads to a lower strength of the formed coke. If, on the contrary, the blending ratio of raw material coals is decided on the basls of the zone near the oven walls, pieces of formed coke in the central zone are not mutually agglomerated, thus making it difficult to discharge the produced coke.
For the purpose of obtaining a formed coke in mutual agglo-meration as mentioned above, a method has been proposed, which comprises charging only a formed coal produced by blending raw material coal fines so a6 to give a coking index of 80 to 88 into a horizontal slot type coke oven battery and carbonizing said formed coal. According to this method, however, it i8 not always possible to obtain a satisfactory formed coke in a slight mutual agglomeration. The coking index is defined a6 an index calculated by ~L~_~ x 100, where:
.
A method is now known for the purpose of improving the coke quality and the productivity, in manufacturing a coke for blast furnace using a conventional, i.e., a horizontal slot type coke oven battery.
Such known method comprises charging briquettes produced by forming r blended raw material coal fines by a compression forming machine (herein-after referred to as "~ormed coal"), into the horizontal slot-type coke oven battery thus carbonizing the formed coal to produce a coke~
According to this method, a coke which is especially useful in a blast furnace is produced either by charging a formed coal and coal fines after r mixing into a horizontal slot type coke oven battery, charging a formed coal and coal fines alternately in horizontal layers into a horizontal slot type coke i oven battery, or charging a formed coal only into a horizontal slot type coke _ oven battery; and then carbonizing the raw materials thus charged. ~
~' In the aforementioned method, in charging a formea coal and coal fines in combination into a horizontal slot type coke oven battery, pieces of formed coal should be completely agglomerated with surrounding coal fines during the process of carbonizatian. For this purpose, it is necessary to use raw material coals having a somewhat high fluidity in carbonizing, and this not only imposes certain limits on the range of selection and blending of raw materiaI coals used. but also necessitates troublesom charging practices into the horizontal slot type .
coke oven battery.
When only a formed coal is charged into a horizontal slot type coke oven battery, wide range of selection and blending of raw materlal coals uaed, i~ available and the charging into a horizontal slot type coke oven battery i8 also easy. In this case, however, the operation of the horizontal slot type coke oven battery is problematic.
~ ' .
. .
More specific~lly? ~ith ~ ~iew to facilltat~ng discharge of an already carbonized for~ed coal ~hereinafter referred to ~s "formed coke~, it is necessary that pieces of ~ormed coke should be mutually agglomerated.
On the other hand, however, a formed coke mutually aggiomerated too firmly remains in the agglomerated state even after discharging, and is not separated into pieces, It is therefore desirable that a formed coke produced by chargIng only a formed coal into a horizontal slot type coke oven battery, being in a ~utually agglomerated state at the time of discharging, should 6e only slightly agglomerated so as to permit easy separation into pieces after discharging. In a horizontal slot type coke oven battery, however, the heating rate differs between the zone near the oven walls and the central zone. If the blend~ng ratio of raw material coals is decided on the basis of the central zone, pleces of formed coke in the zone near the oven walls are mutuahly agglomerated too firmly, and remain in the agglomerated state even after discharging, not permitting separation into pieces, A blending ratio of raw material coals not causing mutual agglomeration of a formed coke, if adopted to avoid the aforementioned drawback, leads to a lower strength of the formed coke. If, on the contrary, the blending ratio of raw material coals is decided on the basls of the zone near the oven walls, pieces of formed coke in the central zone are not mutually agglomerated, thus making it difficult to discharge the produced coke.
For the purpose of obtaining a formed coke in mutual agglo-meration as mentioned above, a method has been proposed, which comprises charging only a formed coal produced by blending raw material coal fines so a6 to give a coking index of 80 to 88 into a horizontal slot type coke oven battery and carbonizing said formed coal. According to this method, however, it i8 not always possible to obtain a satisfactory formed coke in a slight mutual agglomeration. The coking index is defined a6 an index calculated by ~L~_~ x 100, where:
.
- 2 - ~ -, ,, . :.: .
- . . , ,-,, . . . : : ''' .
'', , .. : ,'.: , , ~: ' ': . . . ' . ' ~, .
~063060 A The amount of oversize coke (g) obtained by sleving through a 35 mesh screen a coke produced through carbonization of a mixture consisting of a coal fine with a size of not more than 65 mesh in an amount of 1 g and a coke breeze with a size of 48 to 65 mesh in an amount of 9 g in a crucible at 950 + 20C for 7 minutes; and B: The amount of oversize coke (g) obtained by sieving further through a 48 mesh screen the undersize coke obtained through the 35 mesh screen.
An object of one broad aspect of the present ~`
invention is therefore to provide an improvement in a method for manufacturing a high-strength formed coke for blast furnace in a slight mutual agglomeration using only a formed coal comprising low-grade raw material coals in a horizontal slot type coke oven battery. r In accordance with a broad aspect of the present invention, an improvement is provided in a method for manufacturing a high-strength formed coke in a slight mutual agglomeration solely from formed coal in a conventional horizontal type coke oven battery, which comprises sieving a plurality of different types of raw material coal fines to a size not exceeding 1.5 mm., mixing the plurality of different types of raw material coal fines thus sieved with a binder, forming same to produce a formed coal, charglng only the formed coal into the coke oven battery, and then carbonizing the formed coal in the coke oven :
battery under conventional carbonizing conditions to produce a formed coke, the improvement which comprises: blending ~30 the plurality of different types of coal fines after the sieving ' ~ ~ ' I !
:~ , . ~ , ~ ~ ~ _3_ : ~ .
. . . . .. . . . . . .. . .
step to form a mixture of coal fines so as to satisfy the following conditions: (a) AP index: 75 at the minimum, ,.
(b) Mean maximum reflectance. 1.20% at the minimum, and (c) A [dilatation] - [contraction] value of from -2% to +5% when carbonized under conventional conditions in the coke oven battery at a heating rate of 5C./min. (350 - 600C.);
whereby the formed coke has a percentage of co-agglomeration within a range of from 40 to 90%.
~' ~' , ,".
~ ~ '' , , ' .
-3a-~ _,, , . ..................... . .. __._ .. . - . ;. . , . . , . , , . : : . ; - -... . ,,:
-. . . -: . .: ..... . .
:: :
. ,. , ' , . . , ' : .. ' . ., . :
'. . . . . , '' ' , . '.' ': `. '. ~' ' '. ~ ' . ' ' :' ' --` 1063060 ~ Y ~ iant of this ~spect, the fo~med coal is formed into b~iquettes each having a groove on the uppe~ and the lo~er surface thereof, respectively.
In the accompanying drawings, Figure 1 is a graph illustrating the relation between the size of raw material coal fines ~as abgclssa~ for formed coal and the degree of co-agglomeration of a formed coke ~as ordinate~;
Figure 2 i5 a graph illustrating, in terms of the coke strength, the relation between the mean maximum reflectance (as abscissa2 and the AP index of blended raw material coal fines (as ordinate);
Figure 3 is a graph illustrating the relating bet~een the value [dilatation] - [contsaction] of a formed coal in coking (as abscissa) and the percentage of co-agglomeration of a formed coke (as ordinate);
Pigures 4 (a) and (b) are sectional Yiews of conyentional molds used for producing a formed coal; and Figures 4 (c) and (d) are sectional views of more desirable molds for use in the method of an aspect of the present invention.
The inventors conducted an intensive study on the method for manufacturing a formed coke using a conventional, l.e., a horizontal slot type coke oven battery, and found as a result the possibility of obtaining a high-strength formed coke for blast furnace in a slight mutual agglomeration by: sieving raw material coal fines to a size not exceeding 1.5 mm; blending the raw material coal fines thus sieved so as to satisfy the following conditions:
~a) AP index: 75 at the minimum, (b) Mean maximum reflectance: 1.20 % at the minimu~, and (c) lDilatation] - [contraction] in carbonizing at a hea~ti~g ~ate of 5C~min, (35Q - 6QQC): -2X to +5 %;
mixing the blented raw material coal fines thus obtained by adding a - : .
--`` 1063060 binder, and fo~ing the s~me in a compre~sion fomming machine to produce a formed coal; and then, charging the formed coal thus obtained ~nto a horizontal slot type coke oven battery, and carbonizing the same.
In an aspect of the present invention, the size of biended ra~ material coal fines Por formed coal is limited to 1.5 mm and below in view of the relation between the size of blended raw material coal fines and the degree of co-agglomeration of formed coke shown in Figure 1.
The degree of co-agglomeration as herein employed ig defined as an index representing the degree of mutual agglomeration between pieces of formed coke. This value is expressed by 3 in the case where, in carbonizing only a formed coal into a formed coke, the pieces of formed coke are mutually agglomerated firmly and a force applled to separate pieces of said formed coke would result, not in the separation at agglomeration interfaces, but in the breakout of individual pieces of the formed coke.
The value ia expressed by 0 in the case where the pieces of formed coke mutually agglomerated are separated at agglomeration interfaces by the application of a relatively small force, Figures 1.0, 1.5 and 3,Q
indicated on the abscissa of Figure 1 mean that the size of the blended raw material coal fines does not exceed 1.0 mm, 1.5 mm and 3.0 mm, respectlvely.
As mentioned above, both a too firm mutual agglomeration and the non-mutual-agglomeration are not desirable for a formed coke. The degree of co-agglomeration is preferably under 1, and more preferably Q, In an aspect of the present invention, a degree of co-agglomeration of this order is referred to as a slight co-agglomeration. As is clear from Figure 1, in terms of the AP index described later, a size of raw material coal fines not exceeding 1.5 mm leads to a degree of co-agglomeration of formed coke of as low as under 1 or even 0 in most cases, thus leading to a desirable slight co-agglomeration of a formed coke.
Al~o in an aspect of the present ~nyention, the AP index is limited to 75 at the min i , and the mean maximum reflectance, to 1.20 ~
at the minimum, in view of the relation between the mean maximum reflectance ' ~`
. 1063060 and the AP index of blended ~aw ~te~i~l coal fines, shown in Figure 2 with regard to the st~en~th DIl5 of a formed coke~ ~ ;
The AP index, an abbreviation of the Agglomeration PropertY
Index, of blended raw material coal fines, herein employed, is defined as a percentage obtained by: crushing a coal sample in an amount of 35 g to a size not exceeding l mm; producing a formed coal by adding a lO wt.% .
binder and by forming the mixture in a compression forming machine under a pressure of 300 kg/cm2; charging said formed coal in an experimental coke oven at an oven temperature of 500C and carbonizing the same to a !
final temperature of 900C to produce a formed coke in a briquette form; ~r putting the formed coke thus obtained into a small-sized drum (200 mm dia.
x 70 mm long, S0 r.p.m.); after turning said drum l,000 times, sieving the formed coke through a 3 mm screen; and calculating the ratio of the oversize coke weight to the formed coke weight before sieving. This AP
index is a property which has been created by the inventors. The mean maximum reflectance is obtained by: crushing a coal sample to a size not ~ ;
exceeding 20 mesh; freezing the crushed coal sample with an acrylic resin and polishing same; and measuring the reflectance of light of the vitrinite in an oil in compliance with ASTM-2797-69T and 2798-69T.
It is in general desirable that a coke for a blast furnace should bave a coke strength DIl50 of at least 92Ø As is evident from Figure 2, in an aspect of this invention a formed coke having a coke strength DIl5 of at least 92.0 is obtained only when using a formed coal produced from blended raw material coal fines having an AP index of at least 751and a mean maximum reflectance of at least 1.20 %. The results of measurement shown in Figure 2 refer to a case where a formed coke was produced by carbonizing a formed coal under the following conditions:
Size of blended raw material coal fines: 1.5 mm at the maximum, Amount of binde~: lO ~t,X (C/H: 0,72), and r---Heating rate: 5.5C/min. (400 - 600C).
- In an aspect of the present invention, furthermore, tbe value ".
.. . : , _ .
.
, ~. 1.
[dilatation] - [cont~action] of a formed coal in carbonizing at a heating rate of 5C~in, (350 - 600C) is limited to a range from -2 % to ~ -+5 %, in view of the relation between the value [dilatation] of a formed coal in carbonizing and the percentage of co-agglomeration of a formed coke shown in Figure 3. The percentage of co-agglomeration herein employ-ed is defined as a percentage representing the state of mutual agglomera- ~ -tion between pieces of a formed coke produced by carbonizing only a formed coal, with 100 % for the case in which all the pieces of formed coke are mutually agglomerated, and with 0 % for the case with no mutual agglomeration between the pieces of formed coke. The value [dllatation] -[contraction] as used in various aspects of the present invention is in conformity to DIN-51739. _ As mentioned above, pieces of a formed coke should preferably be in a slight mutual agglomeration, and a formed coke in this preferable slight mutual agglomeration is obtained when said percentage of co-agglomer-ation is within the range from 40 to 90 %. In other words, a formed coke with a degree of co-agglomeratlon of under 1 or re preferably of 0 is obtained when said percentage of co-agglomeration is within the range ~
from 40 to 90 %. As is clear from Figure 3, when using a formed coal ~s with a value [dilatation] - [contraction] in the range from -2 % to +5 %
in carbonizing, the percentage of co-agglomeration of formed coke lies within the range from 40 to 90 %. The results of measurement shown in Figure 3 refer to a case where a formed coke was produced by carbonizing a formed coke under the following conditions: !
Size of blended raw material coal fines: 1.5 mm _ at the maximum, Amount of binder: 10 wt.% (C/H: 0.72~, and Heating rate: 5.5C/min. (350 - 600C).
.~, U8ually, two ~emi-sphe~ical mold8 as shown in the 8ectional ~
views of Flgure 4(a) ~nd (b) are conventionally e~ployed for producing r a formet coal. The possibility was however found to obtain the following favorable merits:
P~ . !
~,' .:'" '' "' ' ' ~'. ., '' " ', ' , ' (1~ MechAn~c~l strength of a ~o~ed coal and a formed coke are not impa~red;
(2? In a horizontal slot type coke oven battery, the larger contact area between pieces of a formed coke permits easier discharge of coke even with a low degree of co-agglomeration of the formed coke; and ~3) In charging a formed coke into a blast furnace, the permeability resistance is smaller than in a conventional formed coke. In addition, the more active convection heat conduction in carbonizing a formed coal in a horizontal slot type coke oven battery leads to a smaller difference in the carbonizing conditions in the oven width direc-tion than in a conventional one, by using two molds having a ridge at the center as shown in the sectional views of Figure 4(c) and (d), and by producing pieces of formed coal in the form of briquettes each having a groove on the upper and the lower surfaces, respectively.
Now, certain aspects of the present invention is described further in detail with reference to some embodiments.
Raw material coal fines having a size not exceeding 1.5 mm were blended as follows:
Black Water Coal: 20%
Big Ben Coal: 25%, and Kuznetsk OS Coal: 55%
to obtain blended raw material coal fines presenting an AP index of 90.0, a mean maximum reflectance of 1,35 ~, a value ~dilatation] - [contraction]
3Q in carb~nlzing at a heating rate of 5C~min, (350 - 600C) of ~2 X, an ash, content of 8.5 % and a volatile matter content of 23.8 Z. Sait blended raw material coal fines were mixed by adding a 10 wt.% binder ~:
- - - . , ~
... . , , . - :
--` 1063060 and ~or~ed in a compression forming machine under a pressure of 3Q0 kg/cm to produce a formed coal. The formed coal was charged into a horizontal slot type coke oven battery, and carbonized into a formed coke. The formed coke thus obtained showed a coke strength DI35 of 92.0 and was in a very good slight mutual agglomeration with a degree of co-agglomeration of 0.
Raw material coal Pines with a size not exceeding 1~5 mm were blended as follows:
Black Water Coal: 20~, -Sprague MH Coal: 25%, Watson Coal: 15%.
Kuzunetsk OS Coal: 30% ,and Petroleum Coke 10%
to obtain blended raw material coal fines havinR an AP index of 87.7, a mean maximum reflectance of 1.49%, a value [dilatation] - [contraction] in carbonizin~ at a heatin~ rate of 5C/min. (350 - 600C) of 3 %, an ash content of 11.4 %, and a volatile matter content 21.4 %. Then, a formed coal was produced in the same manner as in Example 1, and a formed coke was manufactured by carbonizing said formed coal. The formed coke thus obtained showed a coke strength D~3~ o 92.3 and was in very good slight mutual agglomeration with a degree of co-agglomeration of 0.
According to aspects of the present invention, as described in detail above, it is possible to manufacture a formed coke having a coke strength necessary for blast furnace and in slight mutual agglomeration to a desirable extent, in a horizontal slot type coke oven battery, from low-grade raw material coal fine6, thus providing industrially useful effects.
_g_ . .
.. :. , : , . , ~ . s
- . . , ,-,, . . . : : ''' .
'', , .. : ,'.: , , ~: ' ': . . . ' . ' ~, .
~063060 A The amount of oversize coke (g) obtained by sleving through a 35 mesh screen a coke produced through carbonization of a mixture consisting of a coal fine with a size of not more than 65 mesh in an amount of 1 g and a coke breeze with a size of 48 to 65 mesh in an amount of 9 g in a crucible at 950 + 20C for 7 minutes; and B: The amount of oversize coke (g) obtained by sieving further through a 48 mesh screen the undersize coke obtained through the 35 mesh screen.
An object of one broad aspect of the present ~`
invention is therefore to provide an improvement in a method for manufacturing a high-strength formed coke for blast furnace in a slight mutual agglomeration using only a formed coal comprising low-grade raw material coals in a horizontal slot type coke oven battery. r In accordance with a broad aspect of the present invention, an improvement is provided in a method for manufacturing a high-strength formed coke in a slight mutual agglomeration solely from formed coal in a conventional horizontal type coke oven battery, which comprises sieving a plurality of different types of raw material coal fines to a size not exceeding 1.5 mm., mixing the plurality of different types of raw material coal fines thus sieved with a binder, forming same to produce a formed coal, charglng only the formed coal into the coke oven battery, and then carbonizing the formed coal in the coke oven :
battery under conventional carbonizing conditions to produce a formed coke, the improvement which comprises: blending ~30 the plurality of different types of coal fines after the sieving ' ~ ~ ' I !
:~ , . ~ , ~ ~ ~ _3_ : ~ .
. . . . .. . . . . . .. . .
step to form a mixture of coal fines so as to satisfy the following conditions: (a) AP index: 75 at the minimum, ,.
(b) Mean maximum reflectance. 1.20% at the minimum, and (c) A [dilatation] - [contraction] value of from -2% to +5% when carbonized under conventional conditions in the coke oven battery at a heating rate of 5C./min. (350 - 600C.);
whereby the formed coke has a percentage of co-agglomeration within a range of from 40 to 90%.
~' ~' , ,".
~ ~ '' , , ' .
-3a-~ _,, , . ..................... . .. __._ .. . - . ;. . , . . , . , , . : : . ; - -... . ,,:
-. . . -: . .: ..... . .
:: :
. ,. , ' , . . , ' : .. ' . ., . :
'. . . . . , '' ' , . '.' ': `. '. ~' ' '. ~ ' . ' ' :' ' --` 1063060 ~ Y ~ iant of this ~spect, the fo~med coal is formed into b~iquettes each having a groove on the uppe~ and the lo~er surface thereof, respectively.
In the accompanying drawings, Figure 1 is a graph illustrating the relation between the size of raw material coal fines ~as abgclssa~ for formed coal and the degree of co-agglomeration of a formed coke ~as ordinate~;
Figure 2 i5 a graph illustrating, in terms of the coke strength, the relation between the mean maximum reflectance (as abscissa2 and the AP index of blended raw material coal fines (as ordinate);
Figure 3 is a graph illustrating the relating bet~een the value [dilatation] - [contsaction] of a formed coal in coking (as abscissa) and the percentage of co-agglomeration of a formed coke (as ordinate);
Pigures 4 (a) and (b) are sectional Yiews of conyentional molds used for producing a formed coal; and Figures 4 (c) and (d) are sectional views of more desirable molds for use in the method of an aspect of the present invention.
The inventors conducted an intensive study on the method for manufacturing a formed coke using a conventional, l.e., a horizontal slot type coke oven battery, and found as a result the possibility of obtaining a high-strength formed coke for blast furnace in a slight mutual agglomeration by: sieving raw material coal fines to a size not exceeding 1.5 mm; blending the raw material coal fines thus sieved so as to satisfy the following conditions:
~a) AP index: 75 at the minimum, (b) Mean maximum reflectance: 1.20 % at the minimu~, and (c) lDilatation] - [contraction] in carbonizing at a hea~ti~g ~ate of 5C~min, (35Q - 6QQC): -2X to +5 %;
mixing the blented raw material coal fines thus obtained by adding a - : .
--`` 1063060 binder, and fo~ing the s~me in a compre~sion fomming machine to produce a formed coal; and then, charging the formed coal thus obtained ~nto a horizontal slot type coke oven battery, and carbonizing the same.
In an aspect of the present invention, the size of biended ra~ material coal fines Por formed coal is limited to 1.5 mm and below in view of the relation between the size of blended raw material coal fines and the degree of co-agglomeration of formed coke shown in Figure 1.
The degree of co-agglomeration as herein employed ig defined as an index representing the degree of mutual agglomeration between pieces of formed coke. This value is expressed by 3 in the case where, in carbonizing only a formed coal into a formed coke, the pieces of formed coke are mutually agglomerated firmly and a force applled to separate pieces of said formed coke would result, not in the separation at agglomeration interfaces, but in the breakout of individual pieces of the formed coke.
The value ia expressed by 0 in the case where the pieces of formed coke mutually agglomerated are separated at agglomeration interfaces by the application of a relatively small force, Figures 1.0, 1.5 and 3,Q
indicated on the abscissa of Figure 1 mean that the size of the blended raw material coal fines does not exceed 1.0 mm, 1.5 mm and 3.0 mm, respectlvely.
As mentioned above, both a too firm mutual agglomeration and the non-mutual-agglomeration are not desirable for a formed coke. The degree of co-agglomeration is preferably under 1, and more preferably Q, In an aspect of the present invention, a degree of co-agglomeration of this order is referred to as a slight co-agglomeration. As is clear from Figure 1, in terms of the AP index described later, a size of raw material coal fines not exceeding 1.5 mm leads to a degree of co-agglomeration of formed coke of as low as under 1 or even 0 in most cases, thus leading to a desirable slight co-agglomeration of a formed coke.
Al~o in an aspect of the present ~nyention, the AP index is limited to 75 at the min i , and the mean maximum reflectance, to 1.20 ~
at the minimum, in view of the relation between the mean maximum reflectance ' ~`
. 1063060 and the AP index of blended ~aw ~te~i~l coal fines, shown in Figure 2 with regard to the st~en~th DIl5 of a formed coke~ ~ ;
The AP index, an abbreviation of the Agglomeration PropertY
Index, of blended raw material coal fines, herein employed, is defined as a percentage obtained by: crushing a coal sample in an amount of 35 g to a size not exceeding l mm; producing a formed coal by adding a lO wt.% .
binder and by forming the mixture in a compression forming machine under a pressure of 300 kg/cm2; charging said formed coal in an experimental coke oven at an oven temperature of 500C and carbonizing the same to a !
final temperature of 900C to produce a formed coke in a briquette form; ~r putting the formed coke thus obtained into a small-sized drum (200 mm dia.
x 70 mm long, S0 r.p.m.); after turning said drum l,000 times, sieving the formed coke through a 3 mm screen; and calculating the ratio of the oversize coke weight to the formed coke weight before sieving. This AP
index is a property which has been created by the inventors. The mean maximum reflectance is obtained by: crushing a coal sample to a size not ~ ;
exceeding 20 mesh; freezing the crushed coal sample with an acrylic resin and polishing same; and measuring the reflectance of light of the vitrinite in an oil in compliance with ASTM-2797-69T and 2798-69T.
It is in general desirable that a coke for a blast furnace should bave a coke strength DIl50 of at least 92Ø As is evident from Figure 2, in an aspect of this invention a formed coke having a coke strength DIl5 of at least 92.0 is obtained only when using a formed coal produced from blended raw material coal fines having an AP index of at least 751and a mean maximum reflectance of at least 1.20 %. The results of measurement shown in Figure 2 refer to a case where a formed coke was produced by carbonizing a formed coal under the following conditions:
Size of blended raw material coal fines: 1.5 mm at the maximum, Amount of binde~: lO ~t,X (C/H: 0,72), and r---Heating rate: 5.5C/min. (400 - 600C).
- In an aspect of the present invention, furthermore, tbe value ".
.. . : , _ .
.
, ~. 1.
[dilatation] - [cont~action] of a formed coal in carbonizing at a heating rate of 5C~in, (350 - 600C) is limited to a range from -2 % to ~ -+5 %, in view of the relation between the value [dilatation] of a formed coal in carbonizing and the percentage of co-agglomeration of a formed coke shown in Figure 3. The percentage of co-agglomeration herein employ-ed is defined as a percentage representing the state of mutual agglomera- ~ -tion between pieces of a formed coke produced by carbonizing only a formed coal, with 100 % for the case in which all the pieces of formed coke are mutually agglomerated, and with 0 % for the case with no mutual agglomeration between the pieces of formed coke. The value [dllatation] -[contraction] as used in various aspects of the present invention is in conformity to DIN-51739. _ As mentioned above, pieces of a formed coke should preferably be in a slight mutual agglomeration, and a formed coke in this preferable slight mutual agglomeration is obtained when said percentage of co-agglomer-ation is within the range from 40 to 90 %. In other words, a formed coke with a degree of co-agglomeratlon of under 1 or re preferably of 0 is obtained when said percentage of co-agglomeration is within the range ~
from 40 to 90 %. As is clear from Figure 3, when using a formed coal ~s with a value [dilatation] - [contraction] in the range from -2 % to +5 %
in carbonizing, the percentage of co-agglomeration of formed coke lies within the range from 40 to 90 %. The results of measurement shown in Figure 3 refer to a case where a formed coke was produced by carbonizing a formed coke under the following conditions: !
Size of blended raw material coal fines: 1.5 mm _ at the maximum, Amount of binder: 10 wt.% (C/H: 0.72~, and Heating rate: 5.5C/min. (350 - 600C).
.~, U8ually, two ~emi-sphe~ical mold8 as shown in the 8ectional ~
views of Flgure 4(a) ~nd (b) are conventionally e~ployed for producing r a formet coal. The possibility was however found to obtain the following favorable merits:
P~ . !
~,' .:'" '' "' ' ' ~'. ., '' " ', ' , ' (1~ MechAn~c~l strength of a ~o~ed coal and a formed coke are not impa~red;
(2? In a horizontal slot type coke oven battery, the larger contact area between pieces of a formed coke permits easier discharge of coke even with a low degree of co-agglomeration of the formed coke; and ~3) In charging a formed coke into a blast furnace, the permeability resistance is smaller than in a conventional formed coke. In addition, the more active convection heat conduction in carbonizing a formed coal in a horizontal slot type coke oven battery leads to a smaller difference in the carbonizing conditions in the oven width direc-tion than in a conventional one, by using two molds having a ridge at the center as shown in the sectional views of Figure 4(c) and (d), and by producing pieces of formed coal in the form of briquettes each having a groove on the upper and the lower surfaces, respectively.
Now, certain aspects of the present invention is described further in detail with reference to some embodiments.
Raw material coal fines having a size not exceeding 1.5 mm were blended as follows:
Black Water Coal: 20%
Big Ben Coal: 25%, and Kuznetsk OS Coal: 55%
to obtain blended raw material coal fines presenting an AP index of 90.0, a mean maximum reflectance of 1,35 ~, a value ~dilatation] - [contraction]
3Q in carb~nlzing at a heating rate of 5C~min, (350 - 600C) of ~2 X, an ash, content of 8.5 % and a volatile matter content of 23.8 Z. Sait blended raw material coal fines were mixed by adding a 10 wt.% binder ~:
- - - . , ~
... . , , . - :
--` 1063060 and ~or~ed in a compression forming machine under a pressure of 3Q0 kg/cm to produce a formed coal. The formed coal was charged into a horizontal slot type coke oven battery, and carbonized into a formed coke. The formed coke thus obtained showed a coke strength DI35 of 92.0 and was in a very good slight mutual agglomeration with a degree of co-agglomeration of 0.
Raw material coal Pines with a size not exceeding 1~5 mm were blended as follows:
Black Water Coal: 20~, -Sprague MH Coal: 25%, Watson Coal: 15%.
Kuzunetsk OS Coal: 30% ,and Petroleum Coke 10%
to obtain blended raw material coal fines havinR an AP index of 87.7, a mean maximum reflectance of 1.49%, a value [dilatation] - [contraction] in carbonizin~ at a heatin~ rate of 5C/min. (350 - 600C) of 3 %, an ash content of 11.4 %, and a volatile matter content 21.4 %. Then, a formed coal was produced in the same manner as in Example 1, and a formed coke was manufactured by carbonizing said formed coal. The formed coke thus obtained showed a coke strength D~3~ o 92.3 and was in very good slight mutual agglomeration with a degree of co-agglomeration of 0.
According to aspects of the present invention, as described in detail above, it is possible to manufacture a formed coke having a coke strength necessary for blast furnace and in slight mutual agglomeration to a desirable extent, in a horizontal slot type coke oven battery, from low-grade raw material coal fine6, thus providing industrially useful effects.
_g_ . .
.. :. , : , . , ~ . s
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a method for manufacturing a high-strength formed coke in a slight mutual agglomeration solely from formed coal in a conventional horizontal type coke oven battery, which comprises sieving a plurality of different types of raw material coal fines to a size not exceeding 1.5 mm., mixing said plurality of different types of raw material coal fines thus sieved with a binder, forming same to produce a formed coal, charging only said formed coal into said coke oven battery, and then carbonizing said formed coal in said coke oven battery under conventional carbonizing conditions to produce a formed coke, the improvement which comprises:
blending said plurality of different types of coal fines after said sieving step to form a mixture of coal fines so as to satisfy the following conditions:
(a) AP index: 75 at the minimum, (b) Mean maximum reflectance: 1.20% at the minimum, and (c) A [dilatation] - [contraction] value of from -2% to +5°C when carbonized under conventional conditions in said coke oven battery at a heating rate of 5°C./min. (350-600°C.);
whereby said formed coke has a percentage of co-agglomeration within a range of from 40 to 90%.
blending said plurality of different types of coal fines after said sieving step to form a mixture of coal fines so as to satisfy the following conditions:
(a) AP index: 75 at the minimum, (b) Mean maximum reflectance: 1.20% at the minimum, and (c) A [dilatation] - [contraction] value of from -2% to +5°C when carbonized under conventional conditions in said coke oven battery at a heating rate of 5°C./min. (350-600°C.);
whereby said formed coke has a percentage of co-agglomeration within a range of from 40 to 90%.
2. The method claimed in claim 1, wherein said formed coal is formed into briquettes each having a groove on the upper and the lower surface thereof, respectively.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3856275A JPS51114402A (en) | 1975-04-01 | 1975-04-01 | Process for producing one-side fused shaped coke |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063060A true CA1063060A (en) | 1979-09-25 |
Family
ID=12528726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA248,526A Expired CA1063060A (en) | 1975-04-01 | 1976-03-22 | Manufacturing formed coke |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS51114402A (en) |
| CA (1) | CA1063060A (en) |
| DE (1) | DE2613353C3 (en) |
| FR (1) | FR2306251A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3315585A4 (en) * | 2015-06-24 | 2018-05-30 | JFE Steel Corporation | Ferro-coke production method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2385786A1 (en) * | 1977-03-28 | 1978-10-27 | Nord Pas Calais Houilleres | PROCESS FOR OBTAINING MOLD COKE FROM NON-COKEFIABLE COALS |
| US4370201A (en) * | 1981-06-23 | 1983-01-25 | United States Steel Corporation | Process for maintaining coal proportions in a coal blend |
-
1975
- 1975-04-01 JP JP3856275A patent/JPS51114402A/en active Granted
-
1976
- 1976-03-22 CA CA248,526A patent/CA1063060A/en not_active Expired
- 1976-03-29 DE DE19762613353 patent/DE2613353C3/en not_active Expired
- 1976-04-01 FR FR7609516A patent/FR2306251A1/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3315585A4 (en) * | 2015-06-24 | 2018-05-30 | JFE Steel Corporation | Ferro-coke production method |
| US11111441B2 (en) | 2015-06-24 | 2021-09-07 | Jfe Steel Corporation | Method for producing ferrocoke |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2613353B2 (en) | 1978-01-05 |
| DE2613353A1 (en) | 1976-10-14 |
| JPS51114402A (en) | 1976-10-08 |
| FR2306251B1 (en) | 1980-04-04 |
| AU1174376A (en) | 1977-09-15 |
| JPS5332803B2 (en) | 1978-09-11 |
| FR2306251A1 (en) | 1976-10-29 |
| DE2613353C3 (en) | 1978-09-07 |
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