JP2009019173A - Coke oven operation method - Google Patents

Abstract

The present invention relates to a coke oven operating method capable of suppressing generation of a large pressure at the time of coal charging and preventing excessive pressure generation at the time of coal charging to an adjacent kiln when an empty kiln is provided and damage to a furnace wall caused thereby. provide.
In the operation of a coke oven in which coal whose water content is adjusted to 8% by mass or less is charged into a carbonization chamber and carbonized, the carbonization chamber adjacent to the carbonization chamber (empty kiln) not charged with coal is used. Charge coal with moisture adjusted to 8.5% by mass or more. The present invention is particularly effective in a case where a humidity control operation, or an operation using dry coal or preheated coal having a low moisture content as a charging raw material is performed as a normal operation.
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Description

  In the operation of a coke oven in which coal moisture is adjusted low and charged into a coke oven, the pressure acting on the furnace wall of the carbonization chamber not charged with coal is relaxed to damage the furnace wall. The present invention relates to a method for operating a coke oven.

  The chamber-type coke oven used for the production of coke consists of several tens to hundreds of alternating carbonization chambers for charging and carbonizing coal and combustion chambers for supplying heat to the carbonization chamber. Has been. The carbonization chamber is also referred to as “kiln”.

  In a coke oven, coke is generally produced as follows. Coal as a raw material is a mixture of about 10 brands of coal, and after pretreatment such as grinding and particle size adjustment, it is transported to a coal tower by a belt conveyor or the like and temporarily stored. From the coal tower, the coal for one kiln is divided into a coal car, and the coal car that contains this coal travels to the target carbonization chamber on the coke oven, and the coal is charged from the coal car into the carbonization chamber. .

  The coal charged in the carbonization chamber is heated by the combustion chambers disposed on both sides of the carbonization chamber, and first, moisture contained in the coal evaporates. Next, coal is softened and melted at 350 to 500 ° C., and simultaneously pyrolyzed to generate dry distillation gas and tar content. When heated to 500 to 600 ° C. or higher, the coal is re-solidified to be coke, and further heated to about 1000 ° C. to become strong coke.

  Coal is stored outdoors and has an average moisture content of about 8 to 11% (content moisture mass ratio to moisture coal mass). In recent years, the amount of heat contained in the coke oven increases when the moisture content in the coal is high, and in recent years, there has been an increase in operations in which coal is partially dried and conditioned coal whose moisture content has been adjusted to around 6% is charged into the carbonization chamber. ing. In addition, there are coke ovens in which dry coal dried to lower moisture and operation of charging preheated coal preheated to 100 ° C. or more are performed.

  Since the coal in the carbonization chamber is heated by the heat transmitted through the silica brick walls from the combustion chambers on both sides, dry distillation proceeds from the wall side.

  FIG. 1 is a diagram schematically showing a part of a longitudinal cross section of a coke oven in the furnace width direction. A quartz brick wall constituting a furnace wall of a carbonization chamber (a wall that forms a boundary with a combustion chamber, a “heating wall”) To the center of the carbonization chamber (the center in the width direction of the carbonization chamber, which is referred to as “charcoal middle”).

  The state shown in FIG. 1 is a state in which the carbonization of the coal charged into the carbonization chamber has progressed halfway. Coal near the heating wall is first heated and coked to form a coke layer, and a softened layer in which the coal is softened and melted is heated to 350 to 500 ° C. inside. There is a coal layer that has not been heated yet on the middle side of the coal from the softened layer.

  The dry distillation gas and tar generated in the softening layer flow upward through the coke layer, and are discharged and collected from the riser through the space above the carbonization chamber. While carbonized gas and tar are generated and discharged outside the carbonization chamber, they are pyrolyzed on the high-temperature furnace wall and in the space to produce carbon. If there is a lot of carbon production, it will thickly adhere to the furnace wall or ceiling surface of the carbonization chamber, hindering smooth extrusion of coke, or thickly adhere to the furnace wall or ceiling surface of the carbonization chamber, and smooth coke. There are operational problems such as obstructing the extrusion and preventing the gas from being smoothly discharged by adhering to the inner surface of the rising pipe.

  The middle part of the charcoal, the slowest heating, is coke, and when it is heated to near 1000 ° C., the dry distillation in the coke oven is completed.

  When the carbonization is completed, the produced coke is extruded from the carbonization chamber by an extruder. Generally, it is subjected to dry distillation over 18 to 24 hours from charging of coal into the carbonization chamber to extrusion. The coal chamber where the coke is extruded continues to be charged with fresh coal and carbonized. As described above, the coke oven is operated by sequentially repeating the steps of “charging”, “dry distillation” and “extrusion”.

  It usually takes several minutes to 10 minutes from when coke is extruded until the next coal is charged. However, when repairing a damaged carbonization chamber or removing carbon adhering to the carbonization chamber furnace wall by continuing operation, coke is extruded from the carbonization chamber and then new coal is charged. Without leaving the coking chamber empty, the next kiln may continue to be extruded and charged with new coal. One carbonization time, or even several carbonization times or more may elapse while the carbonization chamber is empty. The carbonization chamber in which no coal is charged is referred to as “empty kiln”, and the carbonization chamber filled with coal or coke is referred to as “real kiln”.

  Thus, when providing the empty kiln which does not charge coal, a coke oven will be put in the dangerous state which is undesirable on furnace strength. That is, due to the difference in horizontal pressure (horizontal pressure) acting on the furnace wall from the two carbonization chambers (kiln) sandwiching the combustion chamber, a bending moment is generated in the furnace wall. It has been pointed out that the furnace wall is damaged by exceeding the limit moment in the lower part, the central part on the side of low horizontal pressure.

  FIG. 2 is a conceptual diagram of a furnace wall deformation when subjected to horizontal pressure, and is a longitudinal sectional view schematically showing a combustion chamber and a part of two carbonization chambers sandwiching the combustion chamber. (A) is a case where one of the two carbonization chambers sandwiching the combustion chamber is an empty kiln, and (b) is a case where normal operation is performed and both of the two carbonization chambers are filled with coal or coke.

  As shown in FIG. 2, a furnace wall 1 is provided from the bottom 3 of the coke oven to the lower surface of the ceiling 4, and a carbonization chamber is formed on both sides thereof, and heat is supplied to the carbonization chamber inside the furnace wall 1. A combustion chamber 2 is formed. The combustion chamber 2 is divided into about 30 small chambers (flues) in the furnace length direction, and each is divided by a partition wall. Since there is a partition wall, the heating wall on the empty kiln side and the heating wall on the actual kiln (neighboring kiln) side are bent together.

  In the case of FIG. 2A in which one of the two carbonization chambers sandwiching the combustion chamber 2 is filled with an empty kiln 5 and the other carbonization chamber is filled with coal or coke 6, Since there is no pressure to act, the furnace wall 1 is horizontal pressure (arrow in the figure) only from the adjacent kiln (carbonization chamber filled with coal or coke 6 existing adjacent to the combustion chamber 2 from the empty kiln 5). Will be received). In this case, when a large horizontal pressure is applied from the adjacent kiln, the bending pressure is applied to the furnace wall 1 as it is, and the furnace wall 1 is likely to be damaged.

  In other words, when the furnace wall is subjected to a very large horizontal pressure from one of the two kilns sandwiching the combustion chamber compared to the other empty kiln, the furnace wall bends, and the upper and lower sides of the actual kiln side and the empty kiln side Tensile force is generated at the center of the furnace, causing breakage of the furnace wall bricks and cracking, leading to furnace wall damage. Furthermore, if the horizontal pressure cannot be supported, the furnace wall itself may even collapse.

  On the other hand, in the case of normal operation in which coal or coke is filled, as shown in FIG. 2 (b), horizontal pressures in opposite directions act from both kilns, so that the horizontal pressure is offset and the empty kiln The force acting as a bending pressure on the furnace wall is smaller than that in the case of the above. Further, even if a very large horizontal pressure is applied from one side and the furnace wall 1 tries to bend, since the coal or coke 6 is filled, the reaction force of the deformation is generated and offset, and the bending is suppressed. It is thought that it will not lead to furnace wall damage or collapse.

  Conventionally, the pressure received by the furnace wall 1 of the empty kiln 5 from the adjacent kiln is large enough to damage the furnace wall. Conventionally, when coal softens and melts during dry distillation, it is generated by expanding while generating gas. The gas pressure of the softened layer (taken as the pressure acting on the furnace wall, also called “expansion pressure”) has been considered.

  In order to suppress the expansion pressure acting during the coal carbonization below the allowable limit pressure of the coke oven damage (usually 10 kPa or less), Patent Document 1 obtains the expansion pressure of raw material coal of various brands, A method is disclosed in which the blended coal expansion pressure is calculated based on the arithmetic mean expansion pressure corresponding to the rate, and the blended brand and blending ratio are adjusted so that the blended coal expansion pressure is below the allowable limit pressure.

  Patent Document 2 discloses a method for producing coke that can suppress the expansion pressure to an allowable limit or less even when a large amount of high expansion pressure coal is used by combining high expansion pressure coal and low-rank coal. Has been.

Japanese Patent No. 2562111 Japanese Patent Laid-Open No. 10-245666

  In the case of providing an empty kiln without charging coal, conventionally, the carbonization chamber used as an empty kiln has simply adopted the method of not charging coal, and the other carbonization chamber has a kiln next to the empty kiln ( In many cases, including the carbonization chamber, dry distillation is performed by charging coal as usual. That is, when the operation of charging moisture-controlled coal with adjusted moisture is performed, humidity-controlled coal is charged, and when normal preheated coal operation is performed, preheated coal is charged.

  However, when the present inventors perform a so-called humidity-controlled coal operation in which the moisture content of the coal is adjusted to be low, or when an operation is performed to further charge low-moisture dry coal or preheated coal. Even when coal having a composition in which the gas pressure (expansion pressure) of the softened layer does not increase as described in Patent Document 1 and Patent Document 2 described above is used as a raw material, a large pressure is generated in the carbonization chamber during coal loading. And found that it acts on the furnace wall.

  The excessive pressure generated at the time of coal loading is different from the expansion pressure generated by the gas pressure of the softened layer that is generated when the coal is softened and melted. Therefore, it is shown in Patent Document 1 and Patent Document 2 described above. It cannot be avoided by some ingenuity in coal blending.

  In the operation mode in which a large pressure acts on the furnace wall at the time of coal charging as described above, there is a possibility that the furnace wall is being damaged when an empty kiln is provided. It is necessary to suppress the generation of excessive pressure.

  Conventionally, when repairing a carbonization chamber using an empty kiln, an operation method has been employed in which the amount of charcoal in the adjacent kiln is reduced. However, this technology reduces the temperature of the working chamber as much as possible, lowers the temperature of the combustion chamber, subtracts the amount of coal commensurate with the shortage of heat required for the dry distillation of coal, reduces the amount of coal loaded, It is a method of balancing and is a countermeasure from the viewpoint of improving the repair work environment, and is not implemented for the purpose of reducing excessive stress from the adjacent kiln.

  In addition, this technique has a problem of greatly deteriorating coke productivity because the amount of coal in the carbonization chamber is reduced. Furthermore, by reducing the amount of coal loading, the height of the charged coal bed is lowered, the upper space is increased, the high temperature furnace wall is exposed, the temperature of the space portion is increased, and a large amount of carbon is generated. There are also problems such as troubles in the environment or problems in environmental protection, and the quality of by-product tar and the like deteriorates.

  The present invention has been made in view of such a situation, and when performing so-called humidity-controlled coal operations, or when performing operations using low-moisture dry coal or preheated coal as a charging raw material. Suppressing the generation of a large pressure during charcoal, and the damage to the furnace wall that may have progressed when an empty kiln was installed, i.e. The purpose is to prevent.

  In order to solve the above-mentioned problems, the present inventors have conducted various studies on the cause of excessive pressure during coal loading.

  The excessive pressure at the time of coal loading is generated in the coal bed, and is different from the gas pressure (expansion pressure) of the softened bed generated when the coal is softened and melted. In addition, it occurs when the moisture content of the coal is adjusted to a low level, such as when the humidity control operation is performed, or when the operation of charging dry coal or preheated coal is performed. The inventors of the present invention have a large pressure during coal loading, in which a large amount of dry distillation gas is generated when the coal comes into contact with the hot furnace wall and the bottom of the furnace. It was thought to be caused by the ventilation resistance of the coal seam when exiting into space.

  Therefore, in a coke oven that is operating humidity-controlling coal, when coal with water content adjusted to 6.5% is charged, and without a humidity-conditioning process that reduces water content, it is equivalent to coal in a coal storage state. In the case where coal having a water content of 10.6% was charged, the pressure in the carbonization chamber from coal loading to before extrusion was measured. As will be described in detail later, when coal with moisture adjusted to 6.5% is charged, a very high pressure of 17 to 18 kPa is generated during coal loading (post-coaling time: 0 h). However, when coal having a moisture content of 10.6% was charged, the generated pressure was about 5 kPa.

  As a result of such considerations and examinations using actual furnaces, the excessive pressure during coal loading does not occur simply by charging coal into the limited space of the carbonization chamber. It was concluded that a large amount of dry distillation gas generated suddenly on contact was caused by the ventilation resistance of the coal bed as it passed through the coal bed and escaped into the upper space.

  Based on this pressure generation mechanism at the time of coal loading, in the case of coal with high moisture content, a large amount of water is used to evaporate the moisture in the coal when it is placed in the carbonization chamber and brought into contact with the hot furnace wall or bottom. Since heat is required, the temperature rise of coal is slow, and the amount of dry distillation gas generated can be reduced. In addition, coal with high water content has a low coal bulk density, a high porosity of the coal layer, and a low ventilation resistance, so that the pressure during coal loading can be reduced. Furthermore, it was confirmed that the ventilation resistance of coal with high water content was lower than expected due to the increase in the porosity, and that it was effective in reducing the pressure during coal loading.

  The present invention has been made on the basis of such knowledge, and the gist thereof is the following method of operating a coke oven.

  That is, in the operation of a coke oven in which coal whose water content has been adjusted to 8% by mass or less is charged into a carbonization chamber and carbonized, the carbonization chamber adjacent to the carbonization chamber not charged with coal has a water content of 8.5 mass. The coke oven operating method is characterized by charging coal adjusted to at least%.

  “Moisture” as used herein refers to the moisture measured by the air drying loss measurement method defined in JIS-M8812 (Industrial analysis method for coals and cokes). This moisture is expressed as a percentage of the weight loss when the sample 1g is dried by heating at 107 ° C. for 1 hour. Hereinafter, the moisture content is simply referred to as “%”.

  In addition, as described above, the “carbonization chamber not charged with coal” is also referred to as “empty kiln”, for the purpose of repairing the damaged carbonization chamber, removing carbon adhering to the carbonization chamber furnace wall, etc. It is a carbonization chamber that is left empty during one or several times of dry distillation without charging coal.

  According to the method of operating a coke oven of the present invention, when an empty kiln is provided in operation of a coke oven in which low-moisture coal is charged, such as humidity control operation or operation in which dry coal or preheated coal is charged. In addition, it is possible to suppress an excessive pressure generated at the time of charging coal into the adjacent kiln of the empty kiln, prevent damage to the furnace wall due to the pressure, and contribute to extending the life of the coke oven.

  The operation method of the coke oven according to the present invention is as described above. In the operation of the coke oven in which coal whose water content has been adjusted to 8% or less is charged into the carbonization chamber and dry-distilled, moisture is added to the carbonization chamber adjacent to the empty kiln. This is an operation method for charging coal adjusted to 8.5% or more.

  In the present invention, the premise for the operation of a coke oven using coal whose moisture is adjusted to 8% or less is that when the coal used has a moisture content exceeding 8%, it is usually carbonized next to the empty kiln. Since the same high-moisture coal exceeding 8% is charged in the chamber, the pressure generated at the time of coal loading (post-coaling time: 0h) is not so high, and until the operation method of the present invention is applied. Because there is no.

  In the operation method of the coke oven of the present invention, the moisture content of the coal charged into the carbonization chamber adjacent to the empty kiln is set to 8.5% or more. A very high pressure is generated in the chamber, and as shown in FIG. 2 (a), a large horizontal pressure acts on the furnace wall from the adjacent kiln filled with coal, which tends to damage the furnace wall. Because. The upper limit of the moisture content of the coal is not specifically defined because it is naturally determined, but is preferably 12% or less from the viewpoint of ensuring good handling properties and suppressing the amount of heat consumed in the coke oven.

  The regulation (8.5% or more) on the moisture content of the coal charged into the carbonization chamber next to this empty kiln uses an actual coke oven as shown in the examples to be described later. An operation in which the moisture was changed in a range of 6.5 to 11.4% was performed, and the pressure transition in the carbonization chamber from coal charging to before extrusion was measured and determined. Below, typical examples of measurement results are shown.

  In a coke oven with a length of 16.5m, a height of 7.125m, and a width of 0.46m, where a moisture-controlled coal operation is performed with the coal adjusted to a moisture content of 6.5%, the furnace length direction at the top of the furnace A pipe having an inner diameter of 2 mm (outer diameter of 3 mm) was inserted into the carbonization chamber from a hole provided at substantially the center and connected to a pressure gauge to measure the pressure in the carbonization chamber.

  There are three pipes for pressure measurement, and using steel guide frames, the heights of these pipes for measurement are 0.5m from the bottom of the furnace, each near the heating wall in the furnace width direction. (About 50 mm from the furnace wall), in the charcoal (center in the furnace width direction: about 225 mm from the furnace wall), or near the intermediate position between the heating wall and the charcoal (about 140 mm from the furnace wall).

  After installing the pressure measurement pipe, the same coal as that of ordinary charging coal, adjusted to a moisture content of 6.5%, was charged, and the pressure transition in the carbonizing chamber from coal charging to before extrusion was measured. This is an operation method performed as a conventional example in the embodiment.

  FIG. 3 shows the pressure measurement results in the carbonization chamber. As is clear from FIG. 3, a very high pressure of 17 to 18 kPa is generated at the time of coal loading (post-coaling time: 0 h). In the vicinity of the heating wall, in the vicinity of the intermediate position between the heating wall and charcoal, and in the vicinity of charcoal, when 1.5 h, 10 h, and 15 h have elapsed after coal loading, the peaks in pressure are observed in the respective measurements. This is the gas pressure of the softened layer generated by softening and melting the coal at the position. Since heating proceeds from the furnace wall side, the closer to the furnace wall is measured at an earlier time. Note that the gas pressure of the softened layer is measured high only in the softened and melted portion, and the vicinity of the furnace wall is not simultaneously increased. However, since a coke layer is formed on the furnace wall side of the softening layer in the carbonization chamber, the gas pressure of the softening layer is transmitted to the furnace wall through coke which is solid.

  The gas pressure of the softened layer is not as high as about 3 kPa at most. However, great pressure is generated during coal loading. The pressure at the time of coal charging is a pressure larger than 10 kPa, which is recognized as an allowable limit stress for coke oven damage.

  In the conventional operation method using conditioned coal, when the conditioned coal with moisture adjusted to around 6% is charged in the adjacent kiln of the empty kiln, the pressure exceeding 10 kPa is acting on the furnace wall during the coal loading. become.

  FIG. 4 is a diagram illustrating the pressure measurement result in the carbonization chamber in the operation method performed as an example of the present invention in Examples. In the case where coal having a moisture equivalent to that of coal in a coal storage state is charged into the carbonization chamber without passing through a humidity conditioning step for reducing moisture, the pressure measurement position is the same as the measurement position in the conventional example shown in FIG. The same. The water content of the charged coal was 10.6%.

  It is the same as in the conventional example that the highest pressure generated in the carbonization chamber is during coal loading, but there is a great difference in the magnitude of the pressure. That is, when wet coal that does not adjust moisture was charged, the pressure generated in the lower part of the carbonization chamber was about 5 kPa, which was sufficiently smaller than the allowable limit value.

  The measurement as described above was carried out in an operation performed by changing the moisture of the coal, and the regulation (8.5% or more) regarding the moisture of the coal charged into the adjacent kiln of the empty kiln was established.

  The following method is used to charge coal with a moisture content of 8.5% or more into the carbonization chamber adjacent to the empty kiln when coal with a moisture content of 8% or less is used in normal humidity control. Is applicable.

  For example, the operation of humidity control equipment is stopped, and within that period, coal with a water content of 8.5% or more is sent to one tank of a coal tower divided into tanks, and only that is temporarily stored. Keep it. Thereafter, when charging coal into the adjacent kiln of the empty kiln, coal with a moisture content of 8.5% or more is received from the tank by the charcoal vehicle and charged into the adjacent kiln.

  Moreover, it is also possible to store what made water | moisture content 8.5% or more to the coal discharged | emitted from a humidity control coal plant, for example on a belt conveyor, and to store in a coal tower. In this case, it is necessary to store only the coal whose water content is surely 8.5% or more.

  As explained above, the generation of excessive pressure during coal loading is carried out by charging coal having more water than that used in normal humidity-controlled coal operations into a kiln adjacent to an empty kiln. It is possible to suppress the occurrence of furnace wall damage.

  As described above, in a coke oven having a length of 16.5 m, a height of 7.125 m, and a width of 0.46 m, where a humidity control operation is performed, a pipe connected to a pressure gauge is inserted into the carbonization chamber. The operation was performed by changing the moisture content of the coal to be charged in the range of 6.5 to 11.4%, and the pressure transition in the carbonization chamber from coal loading to before extrusion was measured. The pressure measurement method, measurement position, etc. are as described above. In addition, in order to charge coal with a moisture content of 8.5% or more (in this example, 10.6% and 11.4%), the moisture content is not adjusted and the moisture content is equivalent to that of coal in a coal storage state. Wet wet charcoal was used.

  FIG. 5 is a diagram showing the relationship between the moisture of coal to be charged and the pressure generated during coal loading (pressure during coal loading) by organizing the measurement results. The relationship shown with the broken line is recognized between both.

  From FIG. 5, it can be seen that as the coal moisture decreases, the generated pressure during coal loading increases markedly. FIG. 3 shows an example in which the coal whose water content is adjusted to 6.5% is shown, but it can be predicted that the charging pressure at the time of coal charging will be larger when the coal content is lower. .

  On the other hand, when the water content of the charged coal in the normal operation exceeds 8%, even if the same charged coal as in the normal operation is charged in the adjacent kiln of the empty kiln, the pressure during the charging is the same as the limit furnace wall pressure. To a lesser extent, it is unlikely to lead to damage to the empty kiln wall.

  In normal operation, when the moisture content of the charging coal is adjusted to 8% or less, the higher the moisture content of the coal charged into the adjacent kiln of the empty kiln, the smaller the pressure generated during charging. From FIG. 5, if the moisture content of the charged coal is 8.5% or more, the critical furnace wall stress (10 kPa) is sufficiently lower, so the influence on the furnace wall is reduced.

  In this example, when coal having moisture of 10.6% or 11.4% was charged into the carbonization chamber, wet coal holding moisture in the coal storage state was used. It is also possible to charge coal whose water content has been increased by adding water to the coal adjusted by the coal facility.

  The operation method of the coke oven according to the present invention is to adjust the water content to 8.5% or more in the coking chamber adjacent to the empty kiln in the operation of the coke oven in which coal having a water content of 8% or less is charged into the carbonization chamber and carbonized. It is an operation method to charge the coal. According to this operation method, when an empty kiln is installed in a coke oven operation in which low-moisture coal is charged, such as in a humidity control operation or an operation in which dry coal or preheated coal is charged, Generation | occurrence | production of the excessive pressure which arises at the time of coal charging to a neighboring kiln can be suppressed, damage to a furnace wall can be prevented, and it can contribute to the lifetime extension of a coke oven.

  Therefore, the method for operating a coke oven according to the present invention can be effectively used in the field of coke production.

It is a figure which shows typically a part of longitudinal cross section in the furnace width direction of a coke oven, and is an enlarged view from the silica brick wall which comprises the furnace wall of a carbonization chamber to the center part of a carbonization chamber. It is a conceptual diagram of a furnace wall deformation when subjected to horizontal pressure, and is a longitudinal sectional view schematically showing a combustion chamber and a part of two carbonization chambers sandwiching the combustion chamber. When one of the carbonization chambers is an empty kiln, (b) is a case where both of the two carbonization chambers are filled with coal or coke. It is a figure which shows the pressure measurement result in the carbonization room | chamber before charging coal with a water | moisture content of 6.5% from before charging to extrusion. It is a figure which inserts coal with a water | moisture content of 10.6%, and shows the pressure measurement result in the carbonization chamber from coal charging to before extrusion. It is a figure which shows the relationship between charging coal water | moisture content and the pressure (carbonization pressure) in the carbonization chamber at the time of coalation.

Claims (1)

  In the operation of a coke oven in which coal whose water content is adjusted to 8% by mass or less is charged into the carbonization chamber and carbonized, the carbonization chamber adjacent to the carbonization chamber not charged with coal has a water content of 8.5% by mass or more. A method for operating a coke oven, characterized by charging coal adjusted to the above.

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