JP2014019743A - Method for operating a coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method for operating a coke oven so as to prevent a push-up blockage accompanying the swelling of a coke cake without entailing throughput losses, etc.SOLUTION: In this method for operating a coke oven, an extrusion by an extruder is started by default in a case where the difference of the carbonization chamber ceiling height and the coke cake height is greater than a threshold gap predicted to yield a push-up blockage, whereas in a case where the difference of the carbonization chamber ceiling height and the coke cake height at a coal loading inlet is lesser than the threshold gap and where the arising of a future push-up blockage is predicted, on the other hand, the operation of the extruder is temporarily stopped, and the extrusion of the coke cake is resumed after a period of standing by for the shrinkage thereof.

Description

  The present invention relates to a method for operating a coke oven, and in particular, an operation of a coke oven that is effective for prevention of push-up clogging associated with the rising of the coke cake in the furnace height direction (furnace ceiling direction) observed when the coke cake is extruded. Suggest a method.

The coke oven is a furnace for producing coke by dry distillation of coal charged into a carbonization chamber with heat supplied from an adjacent combustion chamber. The coke thus produced is then opened after opening the furnace doors D ₁ and D ₂ installed at both ends in the length direction (furnace length direction) of the carbonization chamber R shown in FIG. The side end face of the coke cake Cc in a red hot state is pushed in from the opening on the side) using the extruder P, and the coke cake is pushed out from the other (coke side: CS side) opening to make a product.

  In such coke oven operation, when the coke cake in the carbonization chamber is extruded, depending on the condition of the furnace wall and the state of carbonization (shrinkage) of the coal, it is difficult to discharge the generated coke cake, and the so-called pressing is blocked. The phenomenon of clogging occurs. When this clogging occurs, damage to the furnace wall will increase and coke productivity will decrease due to changes in the production schedule, so it is extremely important to improve coke cake extrusion in coke oven operations. is there.

  By the way, the factors governing the extrudability of coking cake in the carbonization chamber include the amount of shrinkage of the coke cake produced after dry distillation in the furnace width direction, the amount of deformation of the coke cake during extrusion, and the state of the furnace wall (attachments, collapse, etc.) The stability of the coke properties can be considered. It is known that the coke cake after dry distillation generally contracts in the furnace width direction and the furnace height direction due to the separation of the internal volatile components. Thereby, for example, a gap (clearance) is generated between the furnace wall and the coke cake side wall surface, and smooth extrusion becomes possible, but the trouble of the clogging still occurs. The main cause is when the resistance between the coke cake and the furnace wall and hearth increases.

  In this regard, the coke cake being extruded spreads in the furnace width direction where it is not subjected to a load when compressed by the extrusion ram of the extruder (see, for example, Non-Patent Documents 1 and 2). Contact will generate a load. It is known that such a load generated when the coke cake contacts the furnace wall is greatly affected by the amount of cracks existing in the coke cake. Coke cake clogging in the carbonization chamber thus occurs is a balance between the amount of shrinkage of the cake in the furnace width direction and the extent of expansion of the cake in the furnace width direction during extrusion, that is, coke cake and furnace wall. Most of the cases are caused by the resistance between the two.

  From this point of view, there have been various proposals for methods for improving the extrudability of coke cake. For example, in Patent Document 1, in the blending of multiple brands of raw coal, the expansion pressure of each single coal is measured in advance, and the expansion pressure of each single coal and the blending ratio of each single coal are obtained. We have proposed a method that averages the expansion pressure of charcoal and adjusts the blending ratio and blending brand so that it is below the allowable limit pressure of the coke oven. Moreover, in patent document 2, in the mixing | blending process of multiple brand raw material coal, it estimates from the average reflectance of the vitrinite of each simple coal which comprises blended coal, and the average reflectance of the blended coal calculated | required based on a blending rate. We propose a method for estimating the extrudability of coke cake using the shrinkage of coke.

  By the way, as a phenomenon of extrusion failure due to clogging of the coke cake, in addition to the above-mentioned “clogging” due to the resistance between the coke cake and the furnace wall, the coke cake swells upward (toward the ceiling) during extrusion, and eventually There is an example of reaching the ceiling and blocking, so-called “push-up clogging”.

  Conventionally, there has been known a method of preventing the “clogging” phenomenon due to the former side wall by managing the value of the extrusion current applied to the extrusion ram representing the resistance when the coke cake is extruded. In this method, as shown in FIG. 2, when clogging due to deformation or collapse of the furnace wall brick occurs, the previous extrusion current value is larger than the current value during normal extrusion (previous), This is a technology that uses the appearance of signs of clogging. However, in the case of the so-called “push-up clogging” of the so-called coke cake, as shown in FIG. 3, the phenomenon corresponding to the sign of clogging, that is, an increase in the extrusion current value due to an increase in the frictional resistance with the furnace wall in advance is Usually it does not appear.

  Regarding the above-mentioned clogging caused by a part of the coke cake coming into contact with the ceiling, factors such as furnace wall brick overhang, carbon adhesion to the wall, growth, or coke cake destruction due to coke fine graining may be considered. The true cause is still unknown. Therefore, in reality, an effective technique for predicting the clogging is not established so far. Therefore, in the current operation of the coke oven, the amount of coal charged is suppressed in advance so as not to cause clogging of the coke cake, and a sufficient space distance is secured between the top of the coke cake and the carbonization chamber ceiling. It corresponds by that.

  In addition to the above-mentioned physical factors, the mechanism of the push-up clogging is not enough for dry distillation of coal in the carbonization chamber, the cake structure is fragile, and the amount of shrinkage of the cake in the furnace height direction is insufficient. The chemical factor of becoming may be considered. For example, when observing the coke strength when the carbonization temperature of coal is a medium to low temperature of 600 ° C. to 900 ° C., it is known that the strength of the coke decreases as the carbonization temperature decreases (Non-patent Document 3). . That is, it is considered that the shortage of dry distillation promotes the tendency of the coke cake to collapse during extrusion.

  As a countermeasure against such a shortage of coke dry distillation, a method for controlling the distribution of the amount charged into the coke oven carbonization chamber has been proposed. For example, in Patent Document 3, as a countermeasure against clogging caused by side walls, a method of adjusting the coal charge distribution in the coking chamber furnace length direction according to the unevenness state of bricks in the coke oven is dealt with. However, in the case of this proposal, when the furnace wall of the carbonization chamber is damaged, temperature control in the furnace length direction or the furnace height direction of the carbonization chamber becomes difficult, resulting in dry distillation unevenness, and as a result, the amount of shrinkage of the coke cake is locally reduced. Besides being reduced, clogging cannot be completely prevented by the physical resistance of the unevenness of the furnace wall itself.

  In Patent Document 4, in order to prevent dry distillation shortage on the discharge side (coke side) due to temperature deviation in the furnace length direction of the combustion chamber, the particle size of the coal charged on the discharge side is reduced by adjusting the belt conveyor conveyance speed. It proposes a method to do. In this case, the reason for reducing the particle size of the coal on the discharge side is to increase the amount of coke shrinkage in the vicinity of the discharge side of the carbonization chamber to reduce the resistance during extrusion.

  However, both Patent Documents 3 and 4 are methods for reducing the friction between the coke cake and the furnace wall in order to avoid clogging caused by the side wall, and the thrust reaches the ceiling due to the rise in the furnace height direction. It does not suggest how to prevent clogging.

JP-A-6-212164 Japanese Patent Laid-Open No. 2006-249174 JP-A-2005-36021 JP 2011-52173 A

Nishioka et al .: “Coke Circular”, Vol. 35, 1986, p. 21-28 Watanabe et al .: “Iron and Copper”, Vol. 84, 1998, p. 165-170 Haruhisa Iwakiri; “Iron and Steel”, Vol. 78 (8), 1992, p. 40-47

  As described above, none of the exemplified prior arts is a method for preventing the coke cake from being pushed up and clogged into the ceiling of the carbonization chamber. However, coke cake height often varies from current and future heights due to the vulnerability of the cake itself, and other causes, and at least some measures should be taken for the future. .

  Accordingly, an object of the present invention is to propose a method for operating a coke oven in order to prevent push-up clogging associated with the swell of coke cake without incurring a decrease in production amount in view of the prior art and the current situation. .

  As a result of studying a method for solving the above-mentioned problems of the prior art and realizing the above-mentioned purpose, the inventors have determined that the coke cake has a coke cake according to the height of the coke cake in the coking oven. In the operation method of the coke oven that determines whether or not to extrude, when the difference between the height of the coking chamber ceiling and the height of the coke cake is larger than the critical interval at which clogging is expected at the coal inlet, the extrusion by the extruder is performed. It was found that the effective means is to stop the operation of the extruder, wait for the coke cake to contract, and resume the extrusion when it is smaller than the limit interval.

  In the coke oven operating method according to the present invention, it is more effective that the limit interval is 600 mm or more.

According to the method of operating a coke oven according to the present invention having the above-described configuration, according to the characteristics of each coking chamber of the coke oven, smooth extruding of the produced coke cake without incurring clogging at present and in the future. As a result, it is possible to expect stable operation and improved productivity of the coke oven.
In addition, according to the present invention, it is possible to estimate an appropriate amount of coal charge for dry distillation that does not impair the extrusion characteristics of each carbonization chamber, and it is possible to more reliably achieve avoidance of coke cake push-up clogging. It becomes like this.

It is sectional drawing which shows the general state in the coke oven carbonization chamber before extrusion. It is a figure which shows the example of the extrusion electric current value during coke cake extrusion at the time of the normal (from the side wall) clogging occurrence. It is a figure which shows the example of the extrusion electric current value during coke cake extrusion at the time of pushing-up clogging generation | occurrence | production. It is a schematic explanatory drawing of the method of measuring coke cake height according to the method of this invention. It is the front view and perspective view of a measuring device for measuring coke cake height used by the present invention. It is sectional drawing of the microwave rangefinder which is a specific example of the measuring apparatus used by this invention.

  The present invention is different from the so-called “clogging”, which is different from the conventional “clogging” which is an obstacle occurring in the furnace width direction due to deformation and collapse of the inner wall and bottom surface of the coke oven, adhesion of various components, growth thereof, and the like. A method is proposed for preventing obstructions occurring in the high direction, especially with the ceiling, ie "clogging up". In other words, in order to eliminate clogging, the processing of the furnace side wall surface and the bottom surface of the furnace which is the cause is effective. However, the clogging is not sufficient only by the processing of the furnace side wall surface and the bottom surface of the furnace. Extrusion is determined according to the amount of swell of the coke cake, or if extrusion is not possible, temporarily interrupt the coke cake for further shrinkage and resume extrusion, and for the next and subsequent extrusions, It is thought to be effective to adjust the reduction of the amount of coal (mixed coal) in anticipation of future push-up clogging from the operating conditions.

FIG. 4 shows the measurement position of the coke cake height. The coke cake height h is determined by removing the lids of the coal inlets G _{1 to} G ₄ at the top of the coke oven furnace and installing non-contact type microwave distance meters M _{1 to} M ₄ . The distance (distance) X between the top surface of the coke cake and the microwave rangefinder is measured in a non-contact manner by the microwave irradiated from the bottom. For the coke cake height h just below the coal inlet, subtract the distance X between the microwave rangefinder and the top surface of the coke cake from the distance H from the bottom surface of the coke oven to the outer surface of the furnace term (the bottom surface of the distance meter). It can ask for. The space height Xs between the top surface of the coke cake and the coke oven ceiling is obtained by subtracting the thickness t from the ceiling brick. The distance X may be measured by inserting a bar from the top.

  Table 1 shows the coke cake height h measured for one coke oven group, and the height Xs of the space between the bottom surface of the ceiling and the top position of the coke cake calculated from the measured coke cake height, The ratio in the furnace group of the critical interval (space height: Xs) and the push-up clogging occurrence rate at the space height Xs are shown. As shown in Table 1, it can be seen that the occurrence rate of push-up clogging increases when the space height (furnace ceiling brick thickness t: including 1400 mm) is 300 to 400 mm and 400 to 500 mm. Therefore, in this case, the coke cake height (maximum height) h generated after dry distillation is about 600 mm as the upper space height of the coke cake (including the furnace roof brick thickness t) X, particularly 600 mm as the critical interval (Xs). It can be said that securing the above is desirable in order to surely avoid future clogging.

  Next, an apparatus for measuring the amount by which the coke cake is pushed up according to the present invention will be described. In the present invention, a heat-resistant non-contact type measuring device that can be transported (moved) is installed at each inlet. FIG. 5 is a front view and a perspective view showing an appearance of a microwave distance meter M which is a specific example of the measuring apparatus, and FIG. 6 is a partial cross-sectional view of the microwave distance meter M. The apparatus for measuring the amount of coke cake thrusting shown in these figures, that is, the microwave distance meter M, has a heat resistant structure as a whole because the room temperature in the coke oven carbonization chamber R usually rises to about 1000 ° C. is necessary.

  For this purpose, the microwave distance meter M has a structure in which a heat insulating bottom plate 1 is provided and blocked in order to cope with high-temperature radiant heat received from the inside of the carbonizing chamber R. Specifically, the antenna is a microwave generator main body 2 made of stainless steel having a cylindrical shape as a whole and a dome shape on the heat insulating bottom plate 1 made of ceramics such as oxide or nitride. A configuration in which is installed is preferable. The microwave generator main body (antenna) 2 is mainly structured at a lower portion, more preferably substantially entirely covered with a heat insulating sheet 3 so as to be able to shield the whole. That is, the entire measuring device (including the flexible hose described below) is configured to be protected from the flame and high-temperature dust rising from the inside of the carbonizing chamber R through the inlet G.

  The microwave generator body 2 includes a microwave generator / receiver 4a inside the top of the dome 2a having a hollow inside, and a sensor 4b outside the top of the dome 2a. Then, the microwave signal received by the sensor 4b is output to the controller 5 and the recording medium / computer 6 that are located at remote locations. The sensor 4b, the controller 5 and the computer 6 are connected by a flexible hose for protecting the cable.

  One or more cold air intake holes 2h are opened in the dome portion 2a of the microwave generator body 2 as necessary, and cold air is introduced into the dome portion 2a through the cold air intake holes 2h. It is preferable that the wave generator / receiver 4a can be cooled. Further, the heat insulating bottom plate 1 is provided with a plurality of adjusting bolts 7 for adjusting the height and the level, and further, although not shown, a moving carrier may be provided.

  As described above, the sensor 4b of the microwave rangefinder M used in the measurement method according to the present invention is connected to the external controller 5 via a cable covered with the heat insulating sheet 3, and By connecting to a terminal such as a computer (PC) 6, it is possible to monitor changes over time in the distance to the top of the coke cake Cc in the carbonization chamber R and the temperature in the dome of the measuring device. In particular, according to the measurement apparatus of the present invention, the instantaneous value of the distance between the top of the coke cake Cc and the measurement apparatus (or the distance to the ceiling) is not due to the microwave irradiated from the microwave generator / receiver 4a. Accurate and continuous measurement with contact.

  In the actual measurement by the measuring device, after the end of the dry distillation, before the extrusion, firstly, remove the one at the measurement position among the charging lids closing the plurality of inlets G existing on the ceiling of each coking chamber of the coke oven. The microwave distance meter M is installed on the charging port G and irradiated with microwaves toward the top surface of the coke cake Cc, so that the distance h of the coke cake height (from the inner surface of the furnace bottom to the top of the cake) is set. Ask.

  In this way, the coke cake height h immediately below the charging inlet is obtained, and the distance Xs between the top of the coke cake immediately below each charging inlet and the ceiling is calculated. If this Xs is equal to or greater than a predetermined interval that does not cause push-up clogging, that is, the limit interval (Xs), the extrusion operation is continued as it is. For example, regarding a certain carbonization chamber, if there is at least one of the coke cake heights h immediately below the four inlets G1 to G4, the critical interval is 600 mm or less, there is a risk of clogging due to insufficient dry distillation. Therefore, it is necessary to reduce at least the next coal loading, and when the limit interval Xs is further 600 mm or less, the extrusion of the coke cake by the extruder is stopped and the coke cake is awaited to shrink. Then resume.

  The following can be said about the coke cake swell phenomenon and the coke cake height measurement position. In general, when extruding coke cake, the extrusion ram of the extruder contacts the coke cake, and the entire coke cake begins to move from where it has advanced 1 to 2 m. Coke cake collapse is small, and the current value when starting to move becomes low. On the other hand, when the movement distance of the extrusion ram until the coke cake starts to move is long, the coke cake collapses and it becomes easy to rise up.

  Since such a coke cake swell phenomenon occurs in a portion close to the extrusion ram, it is preferable to observe from the machine side through one charging hole inside the furnace (# 3 charging hole in the case of 4 holes). However, the higher the coke cake level at the # 1 charging hole on the machine side, the higher the possibility that the coke cake will rise and reach the ceiling near the # 2 charging port. It is preferable to measure with a total of two charging holes up to the next.

  However, although the coke cake height is raised and the extrusion is made after the limit interval Xs becomes 600 mm or less, if Xs does not become 600 mm or less even if time passes, a charcoal hole is opened, Coke cake extrusion may be performed after breaking through.

  The method for operating a coke oven according to the present invention can be applied not only to prevent the coke cake from being pushed up, but also to prevent clogging due to abnormalities in the side wall and bottom surface of the carbonization chamber, or changes in the composition.

G charging port M microwave rangefinder R carbonization chamber 1 heat insulation bottom plate 2 microwave generator body 2a dome part 2h cold air intake hole 3 heat insulation sheet 4a microwave generator / receiver 4b sensor 5 controller 6 calculator 7 adjusting bolt 8 of extruder extrusion ram Cc coke cake H coke oven height h coke cake height X measured distance Xs limit interval t ceiling brick thickness G coal charging hole M microwave rangefinder _D 1, _{D 2} furnace door P extruder

Claims (2)

In the coke oven operating method of determining whether the coke cake can be extruded according to the height of the coke cake in the carbonization chamber of the coke oven,
When the difference between the height of the coking chamber ceiling and the height of the coke cake is larger than the limit interval where push-up clogging is expected, the extrusion by the extruder is started as it is, and when the difference is smaller than the limit interval, A method of operating a coke oven, characterized in that the operation of the extruder is temporarily stopped and the extrusion is resumed after the coke cake shrinks.   The method for operating a coke oven according to claim 1, wherein the limit interval is 600 mm or more.

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