JPH1192765A - Method for preventing evolution of black smoke from stack of coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preventing evolution of black smoke from coke oven stacks which can retard the evolution of black smoke from the stacks by one action in a short period of time. SOLUTION: In the carbonization of a raw coal in coke ovens constituting a group of ovens, the raw coal charged to carbonization rooms is changed to a raw coal having a higher content of powdered coal than usual for only a short period of time, when black smoke evolves or is expected to evolve from the stacks of the coke ovens. Thus, part of the raw coal is filled in the cracks of masonry joints of bricks in the wall of the carbonization rooms, so that the gas sealing properties between the carbonization room and the combustion room is improved. In consequence, it becomes possible to improve the respondability to environmental pollution, such as reduction of dust evolution, reduction of NOx discharge, and reduction of carbon dioxide discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the generation of black smoke from a coke oven chimney. And a method for preventing black smoke from being generated.

[0002]

2. Description of the Related Art In a coke oven, a coke oven (kiln) and a combustion chamber having a heat storage chamber in the lower part are alternately arranged in parallel through a partition wall in a large number of furnace groups (normally 45 to 70 gates / furnace group). Is formed. Coking coal charged to each coking chamber receives conduction heat transfer from the adjacent left and right combustion chambers, and is subjected to about 1000 to 1100 ° C.
The temperature is raised to a level and carbonized over about 16 to 22 hours to form coke. Volatile components in the raw coal are gasified during the heating and distillation process, and the gas is usually cooled from the riser through the dry main, while separating the condensed tar components, pulverized coal and fine coke, etc., and then using a blower. It is transferred to the coke oven gas purification process and collected. On the other hand, the high-temperature waste gas from the combustion chamber is recovered in the lower heat storage chamber in the form of preheating the combustion air, cooled down, and discharged to the atmosphere from the chimney via the flue exhaust line. I have.

[0003] Black smoke is often generated from the chimney of such a coke oven. This is due to cracks or localized crack joints in the partition wall bricks due to deterioration of the furnace body (furnace aging) in the coke oven, temperature change, damage or deformation due to mechanical external friction during coke extrusion. A gap such as a broken portion is generated, and volatile matter generated in the carbonization chamber leaks from the gap as a combustible gas into the combustion chamber, causing incomplete combustion in the combustion chamber, resulting in black smoke generation from the chimney. It is said that. Especially in the initial stage of carbonization where a large amount of carbonized gas is generated, the pressure difference between the carbonization chamber and the combustion chamber is large, and it is recognized that the generation of black smoke increases at a stretch, and this is where the combustible gas leaks to the combustion chamber side. Can be specified to some extent. However, if the properties of the coking coal fluctuate due to fluctuations in the water content in the coking coal charged or the volatile components decrease more than usual, black smoke frequently occurs, and all the coking chambers in the furnace Therefore, it is difficult to specify the location where the combustible gas leaks to the combustion chamber.

[0004] Conventional methods for suppressing the generation of black smoke from a chimney include (1) furnace body repair methods such as dry sealing and mortar spraying on a furnace wall joint (for example, Japanese Patent Publication No. 63-1667).
6, Japanese Patent Application Laid-Open No. 62-288686, etc.), (2) Management action at the time of coal loading for closing fuel gas and exhaust gas amount for each coal loading for a certain period of time (for example, Japanese Patent Application Laid-Open No. 6-256768),
(3) Combustion management actions such as cutting off fuel gas or increasing the amount of combustion air (for example, Japanese Patent Application Laid-Open No. 63-27591)
(4) A waste gas management action for switching waste gas from a combustion chamber to a flue system and a dust collection system by detection of a dust concentration meter (for example, Japanese Patent Application Laid-Open No. 6-63334) has been proposed.

[0005] However, the furnace body repair method (1) is aimed at repairing the furnace unit and preventing gas leakage into the combustion chamber. It takes a considerable number of days, manpower, and equipment to perform it. In addition, dry sealing is a method of spraying the entire carbonization chamber from one location of the charging inlet, and there is a possibility that the joint filling material may not reach all joints due to time restrictions. In addition, when dry sealing is performed, the furnace is in an empty kiln state, and the temperature inside the furnace changes greatly, which may cause new cracks and joints to open. Further, material costs such as spray equipment and mortar are required. Therefore, it is impossible to cope with a situation in which black smoke is predicted from the entire furnace group.

[0006] On the other hand, in the fuel management action at the time of coal charging (2) and the combustion management action of (3), it is necessary to attach an automatic combustion control device having a control valve for fuel gas or exhaust gas to each kiln. Significant equipment renovation costs are required. Reduction of fuel gas supply (gas cut)
And the combustion air volume (increased air ratio)
Disturbance in the temperature distribution in the carbonization chamber is feared, causing fire fall-out and poor carbonization. In addition, there is a disadvantage that the normal combustion management automatic control device (ACC) is turned off and manual action is performed. Further, the waste gas management action of (4) includes a new control device for frequently switching the flue gas system and the dust collection system of the waste gas for each kiln, and a new switching valve and a new dust collection device. It is also necessary to install new equipment and remodel ducts.

[0007] Further, in each of the above management actions (2) to (4), it is inevitable that volatile matter generated in the carbonization chamber leaks as combustible gas into the combustion chamber through a crack portion of a brick joint of the partition wall. It is a black smoke prevention method based on the premise described above, and cannot be said to be a fundamental black smoke prevention measure because there are concerns about problems such as expansion of cracks in brick joints and acceleration of furnace body deterioration. Recently, from the viewpoint of energy saving, the moisture of coking coal (usually 8 ~
10%) has been adopted in most coke ovens by introducing a pre-drying system that keeps it below a certain level (around 6%) by pre-drying it. The occurrence of chimney smoke has become particularly noticeable at times, or when there is a fluctuation factor in which the water content in the raw coal greatly increases or decreases due to heavy rain or the like. In this case, chimney black smoke is generated from the entire coking chamber in the furnace group, so it is extremely difficult to respond in a short period of time with the above-mentioned conventional measures. It has been desired.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, particularly when a stack of black smoke is generated or predicted at the same time when coal is charged into all coking chambers of a furnace group. Prevents the generation of black smoke from the coke oven chimney, which can improve the airtightness of the carbonization chamber in a single action, prevent the flammable gas generated from leaking into the combustion chamber, and suppress the generation of chimney black smoke in a short time It is intended to provide a method.

[0009]

The present inventors have conducted various studies under the actual operating conditions of a coke oven to solve the above-mentioned problems. As a result, the higher the content of pulverized coal in the charged coal, the higher the chimney on the next day. Paying attention to the data analysis result that the Ringerman concentration tends to decrease, when black smoke from the chimney is generated and predicted, it is temporarily changed to fine coal whose pulverized coal content is higher than ordinary coking coal The present inventors have found that the generation of chimney black smoke can be suppressed in a short period of time by the switching, and have completed the present invention.

That is, a first aspect of the present invention is to provide coke coking in a coke oven in which a plurality of kilns each including a carbonization chamber and a combustion chamber are arranged in parallel to form a furnace group. When black smoke is generated or predicted to be generated from the furnace chimney,
By changing the coking coal charged to the coking chamber to coking coal with a higher pulverized coal content than normal in a short period of time, part of the coking coal is embedded in the joint crack of the furnace wall brick of the coking chamber,
A method for preventing the generation of black smoke from a chimney of a coke oven, characterized by improving the gas sealing property between the carbonization chamber and the combustion chamber.

[0011] In the present invention, the period of change to the raw coal having a high content of pulverized coal is preferably in the range of 1 to 7 days. Coking coal with an increased pulverized coal content has a particle size of 3.
It is preferable to use fine particles such that the content of 0 mm or less is higher by 2 to 5 Wt% than that in a normal case. It is preferable that the raw coal having a higher pulverized coal content contains 8 to 10% of pulverized coal having a particle size of 0.1 mm or less. Furthermore,
When the size of ordinary coking coal is adjusted to a particle size of 3.0 mm or less and 77-79%, the coking coal with an increased pulverized coal content is adjusted to a particle size of 3.0 mm or less and 80-83%. It is preferable to change.

According to the present invention, the pulverized coal content is determined by the pressure difference between the combustion chamber and the combustion chamber which is pressurized by the pressure of the combustible gas generated in large quantities from the carbonization chamber immediately after the coal charging and in the initial stage of dry distillation. Part of the raised raw coal is pushed into joint cracks formed in the partition wall bricks on the carbonization chamber side, and becomes dense carbon by heating from the combustion chamber to completely close the joint cracks. As a result, the gas sealing property of the carbonization chamber is improved, the flammable gas is prevented from leaking to the combustion chamber side, the incomplete combustion in the combustion chamber is eliminated, and the generation of black smoke from the chimney is prevented.
Therefore, even when black smoke is rapidly generated from the chimney and the location of the carbonization chamber cannot be specified, or even when there are many locations, it is a short-term changeover to coking coal with a higher pulverized coal content. Black smoke generation from the chimney can be prevented in a short time with only one action.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail. First, ordinary coking coal used in the present invention is not particularly limited as long as it is used as coking coal such as blast furnace coke and casting coke. Generally, high-quality caking coal (strong caking coal and weak caking coal), non-fine caking coal, and the like are measured and blended for each group, and pulverized to a predetermined particle size is used. The particle size of the coking coal is usually adjusted to 77 to 7 with a particle size of 3.0 mm or less.
Adjustments are made within a range of about 9 Wt% as a management index.
At that time, the content of pulverized coal of 0.1 mm or less is usually 6
７7 Wt %%. When such ordinary coking coal is continuously carbonized, for example, heavy rain or CM
When a situation where the water content in the coking coal increases due to regular maintenance, sudden stoppage, etc. of C occurs, black smoke is likely to be generated from the coke oven chimney when the coking coal having a low water content is subsequently charged.

Here, the results of a survey of data for about one and a half years in which the content of pulverized coal in coking coal affects the concentration of chimney Ringermann under actual coke oven operating conditions will be described with reference to FIG. . The vertical axis in FIG. 1 represents the difference (degree) of Ringerman concentration between the day after the change to the coking coal shown on the horizontal axis and the day of the change, according to which the water and volatilization in the coking coal are determined. The general tendency is that coking coal with a low content of pulverized coal with a particle diameter of 0.1 mm or less has a ringerman concentration (degree) from the next day when it is switched to a full coking chamber, although there are other effects as well. It shows that it is higher than the previous day (the day of change). On the other hand, when the content of pulverized coal having a particle diameter of 0.1 mm or less increases, the Ringerman concentration (degree) from the day after the coking coal is switched to the entire coking chamber is lower than the previous day.

For example, when the content of pulverized coal having a particle size of 0.1 mm or less is about 6 to 7%, the difference (degree) in Ringerman concentration between the next day and the previous day shows a high value of 0 or more. On the other hand, when the pulverized coal content is 8% or more, the difference in Ringerman concentration is negative. This means that the chimney emits black smoke,
When the Ringerman concentration increases, the particle diameter is 0.1 m
In the case of raw coal having a pulverized coal content of about 6 to 7% or less, the soot concentration is further increased on the next day, indicating that there is no black smoke generation effect. On the other hand, when the content of pulverized coal was changed to coking coal having a content of 8% or more, the smoke concentration in the chimney dropped one day after the change, indicating that the effect of preventing the generation of black smoke was exhibited.

The present invention has been further studied based on such new findings. The present invention, when black smoke is generated or expected to be generated from the coke oven chimney,
It is characterized in that the raw coal charged into the coking chamber is changed to a raw coal having a higher content of pulverized coal than a normal case for a short period of time. Here, the coking coal whose pulverized coal content is higher than that in the normal case means a pulverized coal content higher than the coking coal immediately before the change. Specifically, it is preferable that the coal is refined so as to be higher by 2 to 5% than the content of the raw coal having a particle diameter of 3.0 mm or less immediately before the change. 8% of pulverized coal having a particle size of 0.1 mm or less is used as the raw coal having a high pulverized coal content.
As described above, those containing 8 to 10% are preferable.

More specifically, when the size of the ordinary raw coal is adjusted to be 77 to 79% of a particle diameter of 3.0 mm or less, the raw coal having an increased pulverized coal content has a particle diameter of 3 to 3%. It is preferable to change the particle size to be adjusted to 80 to 83% of 0.0 mm or less. As a result, the content of pulverized coal having a particle diameter of 0.1 mm or less can be maintained at a high content of about 8 to 10%, which is the most preferable particularly for enhancing the gas sealing effect on the partition wall. Note that the content of particles having a particle size of 3 mm or less is 8
If it is higher than 3%, demerits such as an increase in carbon adhesion to the coke oven riser tube, an increase in the amount of carry-over powder in the coke oven gas purification step, and an increase in the cost of pulverization power, etc. are increased. Further, since the bulk density is reduced, the amount of coking coal charged into the carbonization chamber is reduced, and the coke quality may be adversely affected, which is not preferable. When the particle size of 3 mm or less is 80% or less, the content of pulverized coal having a particle size of 0.1 mm or less is particularly 8%.
Therefore, the effect of preventing the generation of black smoke from the chimney is not exhibited.

There is no particular limitation on the method of adjusting the particle size of the raw coal having such a high content of pulverized coal. The raw coal is measured and blended for each group as described above, and pulverized to a predetermined particle size before being charged into the coking chamber of the coke oven. In this case, in order to increase the pulverized coal content, either the pulverized coal pulverization method or the pulverized coal compounding method may be used. Particle size control by coking coal pulverization method was used for normal coking coal particle size target management,
The motor current control value of the crusher, the standard for adjusting the gap between the repulsion plate and the impact blade of the crusher, and the like are simply changed as appropriate, and standardization is easy. In the particle size control by the pulverized coal blending method, for example, a particle size of 0.1 prepared separately from ordinary pulverized raw coal is used.
Mixing coal with a high pulverized coal content of 1 mm or less,
Alternatively, pulverized coal and / or coke powder having a particle diameter of 0.1 mm or less may be blended.

In the present invention, when black smoke is generated from the coke oven chimney or when black smoke is predicted to be generated, the raw coal is changed to the above-described pulverized coal having a high pulverized coal content. Here, black smoke is predicted to be generated from the coke oven chimney.
(1) When a large temperature fluctuation is given to the coke oven (for example, when the production of coke is reduced, the operating rate fluctuates, the moisture increases or decreases when heavy rain or a typhoon arrives, or the combustion gas composition or supply changes (gas pipe repair, blast furnace (3) Deterioration of furnace body in coke oven (furnace), such as (2) changes in coal properties (for example, change of coal blend, increase or decrease in coal moisture due to CMC regular maintenance, volatile matter fluctuation), etc. Aging, etc.), when damage or deformation occurs due to mechanical external friction during coke extrusion, etc. Note that black smoke from the chimney is not always generated, but as described above. When there is a cause of occurrence, or when it is predicted from a conventional practice, it is most preferable to apply the method of the present invention as a pre-action that matches the timing.

In the present invention, the operation for changing to the coking coal having a high pulverized coal content is performed by waiting for the coke oven charging coal tank storing the normal coking coal to empty until the pulverized coal is removed. It is only necessary to replace the raw coal with a higher content and store it, and to sequentially charge each carbonization chamber in the same manner as before. It is preferable that the period for changing the coking coal be continued at least until the coking coal having a high pulverized coal content is completely charged into the coking chamber of the entire furnace group. Generally, in a normal coke oven, it takes about 16 to 24 hours from the charging of the coking coal into one coking chamber to the removal of the coke obtained by high-temperature carbonization, so that the coking coal with a high pulverized coal content is increased. Can be charged to all coking chambers in about one day.

In the initial stage of dry distillation immediately after charging the raw coal into the carbonization chamber, a large amount of dry distillation gas is generated, and the gas pressure in the carbonization chamber reaches 200 to 1000 mmAq. On the other hand, the gas pressure in the combustion chamber is usually about 5 mmAq. Therefore, a large pressure difference occurs between the carbonization chamber where a large amount of combustible gas is generated and the combustion chamber. In this stage, particularly, pulverized coal having a pulverized coal content higher than that of ordinary coking coal includes pulverized coal having a particle size of 0.1 mm or less, which is the same as the particle size (usually 0.1 mm or less 100%) of conventional mortar for dry sealing. Not only the content is increasing, but also the particle size (0.1-0.3 m
m) Many of those belonging to the distribution are also included.

In the present invention, the pulverized coal having an appropriate particle size distribution is efficiently buried in the joint crack portion of the carbonized room partition wall brick by utilizing a large pressure difference, and is completely closed. It is considered that such a phenomenon occurs at an initial stage within about one hour immediately after charging of the raw coal. The pulverized coal or the like that fills the joint cracks in this way is thermally decomposed by the heat supplied from the combustion chamber to carbonize, but this carbon is eventually densified and the sealing material at the brick joint cracks It plays a role and consequently improves the gas sealing property at the partition wall. As a result, the leakage of the combustible gas generated in the subsequent carbonization chamber into the combustion chamber is reliably prevented.

The joint filling material which plays a role of a sealing material embedded in a joint crack portion or a locally defective portion of the partition wall brick is formed, for example, during coke extrusion or during opening of the coking chamber at the completion of coke extrusion. It is inevitable that air will enter and gradually burn and disappear. Therefore, if the period of change to the finely divided raw coal is too short, the long-term durability of the sealing effect is reduced. On the other hand, if the period of change to coking coal with an increased pulverized coal content is too long, there is a merit in environmental measures that the generation and increase of chimney black smoke can be prevented for a long time beforehand. Increase in the amount of tar sludge,
Disadvantages such as an increase in the amount of power used by the coal crusher and a decrease in the amount of coking coal are produced, so that long-term continuation is economically disadvantageous. Therefore, in the present invention, the action for preventing the generation of black smoke from the chimney or the prediction thereof when black smoke is generated is 1 to 7 days from the day (or the day before the prediction), preferably 2 to 4 days. It is optimum to maintain the sealing effect for a certain degree in terms of both the durability of the sealing effect and the economic efficiency.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. In the following examples, (1) Ringerman value is calculated based on the density of soot discharged from a chimney, passing light rays 100%, 80%, 60%, 40%, 2
In the case of 0% and 0%, the frequency values divided into six levels of 0, 1, 2, 3, 4, and 5 degrees are shown (for example, 0 degrees is all white,
5 degrees is all black). (2) Chimney Ringerman concentration (degree / month / chimney) is 1
This is the average value for one month as a result of automatically measuring the Ringerman value of soot emitted from the chimney of a book every other minute. A higher value indicates that incomplete combustion has occurred in the combustion chamber. (3) The chimney Ringerman concentration peak value is the peak value of the ringerman value of the soot discharged from the chimney immediately after charging the raw coal into each coking chamber. The higher this value is, the higher the leakage of combustible gas into the combustion chamber is in the carbonization chamber with low airtightness.

Example 1 Raw coal (containing 8 to 10% of water) blended and adjusted as ordinary blast furnace coke was ground to a grain size of 3.0 mm or less 78 ± 1.
% (However, the content of pulverized coal of 0.1 mm or less is 7%), and then the moisture content is 6% by the coal humidity control equipment (CMC).
Then, the coke oven and the combustion chamber are alternately arranged, and the coke oven is charged into a coke oven under continuous operation having a total of 285/3 coke ovens to produce coke for a blast furnace under ordinary conditions of carbonization. Under the steady conditions of such a coke oven, the chimney Ringerman concentration (degree / month / chimney) was 0.5 or less.
However, when the moisture content of coking coal fluctuates in the range of 7 to 10% during the regular repair period (about 2 weeks) of CMC, or when the moisture content decreases to 6% after regular repair, etc. Black smoke frequently occurs, and each time the Ringerman concentration becomes 0.5
(Degrees / month / chimney) The days that exceeded the number of days continued for many days.

Therefore, when the water content of the raw coal fluctuates (when the CMC is regularly repaired or suddenly stopped, etc.), the pulverized particle size is 3.0 mm or less.
Frequently carry out the operation to continue the granularity action operation to increase to 2% and to change to the coking coal which has been refined for 2 to 3 days (approximately 2
As a result, it was confirmed that almost no chimney black smoke was generated, and the Ringermann concentration was always stable at 0.3 (degrees / month / chimney) or less. In addition, the average appearance rate of the chimney Ringerman concentration peak value of 3 (degrees / kiln) or more in all the coking chambers 285 gates / 3 furnaces was before carrying out the granularity action operation of coking coal change (about one and a half years). It was 4.5%, but since the implementation (about 10 months), it has decreased significantly to 0.6%. The average value of the concentration of chimney Ringerman (degree / month / chimney) during this period was 0.31 in the former, but decreased to 0.24% in the latter, and the effect of suppressing the generation of black smoke from the chimney was surely confirmed. It was clear that it was being demonstrated. As a result, the amount of generated dust decreases,
Improvements in environmental responsiveness, such as a reduction in NOx emissions and a reduction in carbon dioxide emissions, have been achieved.

Example 2 In the same coke oven as in Example 1, raw coal (containing 8 to 10% water) blended and adjusted as ordinary blast furnace coke as used in Example 1 was ground to a particle size of 3.0 mm. Below 7
8 ± 1% (however, the content of pulverized coal less than 0.1 mm is about 6-7
%), And preliminarily dried to a moisture content of 6.0 to 6.5% in a coal humidity control facility (CMC) to produce blast furnace coke under continuous dry distillation conditions under continuous operation. . However, for a certain period, due to the special circumstances of coking coal, the period in which the volatile content gradually decreases from about 28% to 25 to 24% continues, and is a factor of producing densified carbon filling the partition wall joints. In the case where the chimney black smoke, which is considered to be due to the deterioration of the gas sealing effect of the carbonization chamber due to the burning of the densified carbon due to the decrease in the volatile matter content, frequently occurred, and the ringerman concentration was 0.5 degrees / hr or more. For 21 days. Therefore, while the operation of the low volatile content coking coal having a volatile content of about 25% was continued, a change operation of increasing the pulverized particle size from 78% of 3.0 mm or less to 80% was continued for 3 days. The average concentration was reduced from 0.7 (degrees / month / chimney) to 0.45 (degrees / month / chimney). Furthermore, as a result of continuing a change operation for increasing the pulverized particle size from 80% to 82% from 3.0 mm or less for 3 days, the average value of the Ringerman concentration was changed from 0.45 (degrees / month / chimney) to 0.3 (degrees / month).
Moon / chimney). From this, it was confirmed that the effect of suppressing the generation of black smoke from the chimney of the present invention even under low volatile coal operating conditions.

[0028]

According to the present invention, it is possible to change to a coking coal having a different crushing particle size without using special equipment investment or equipment remodeling, and without using materials such as mortar and spraying equipment. The action alone can suppress or prevent the occurrence and increase of chimney black smoke in a relatively short period of time. This reduces the amount of dust generated,
The effect of improving environmental responsiveness, such as a reduction in NOX emission and a reduction in carbon dioxide emission, is also exhibited. Furthermore, while contributing to an increase in the recovery of coke oven gas, the number of times of establishing an emergency kiln mouth repair strengthening system by suppressing the generation of chimney black smoke has been reduced,
As a result, the number of furnace body repairs is reduced and the life of the coke furnace body is prolonged.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between charged coal having different pulverized coal content ratios in a coke oven and a difference in the concentration of chimney Ringerman.

Claims (5)

[Claims] When coking coal is carbonized in a coke oven forming a furnace group by arranging a large number of kilns comprising a carbonization chamber and a combustion chamber in parallel, black smoke is generated from a coke oven chimney. Alternatively, when black smoke is expected to occur, a part of the coking coal is changed into a coking chamber furnace by changing the coking coal charged to the coking chamber to a coking coal with a higher pulverized coal content than normal in a short period of time. A method for preventing generation of black smoke from a chimney of a coke oven characterized by being embedded in a joint crack of a wall brick to improve gas sealing properties of a carbonization chamber and a combustion chamber. 2. The method for preventing black smoke generation from a coke oven chimney according to claim 1, wherein the period of change to coking coal having a higher pulverized coal content is within a range of 1 to 7 days. 3. The raw coal having an increased content of pulverized coal is finely divided so that the content of particles having a particle diameter of 3.0 mm or less is higher by 2 to 5 Wt% than usual. The method for preventing black smoke generation according to claim 2. 4. The raw coal according to claim 1, wherein the pulverized coal having an increased pulverized coal content contains 8 to 10 Wt% of pulverized coal having a particle size of 0.1 mm or less. How to prevent black smoke from the coke oven chimney. 5. An ordinary coking coal having a particle diameter of 3.0 mm or less 77.
The coke oven chimney according to claim 1, wherein when the particle size is adjusted to ~ 79%, the raw coal having a high content of pulverized coal is changed to a particle size adjusted to 80 to 83% with a particle size of 3.0mm or less. Black smoke generation prevention method.