JP2002173687A - Method for estimating pushing load of coke and method for operation of coke oven to prevent clogging trouble in coke pushing work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the clogging of coke in coke pushing work by estimating the load on the motor for the driving of a pusher ram. SOLUTION: The load applied to the ram-driving motor in the coke pushing work is estimated from the relationship between the load on the ram-driving motor and a carbon resistance index calculated from the carbon quantity on the furnace wall and the carbon quantity in the furnace top space estimated from the coal nature and the operating conditions of the furnace. When a high pushing load is estimated, the load is lowered by controlling the coal nature and the operation conditions to prevent the occurrence of the push clogging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a coke oven which can prevent the coke from being clogged.

[0002]

2. Description of the Related Art It is recognized that stable operation of a coke oven is important from the viewpoints of securing the production amount, reducing the production cost, and protecting the furnace body. However, in practice, trouble often occurs due to various reasons, and stable operation cannot be maintained in many cases. As an example of the cause, there is a trouble in equipment such as a failure of a mobile device (a charging vehicle, an extruder, a guide vehicle) and a damage of a brick constituting a coking chamber furnace wall. Alternatively, when coke is extruded, the load of the extruder ram rises abnormally, and the trouble occurs in which the drive motor protection circuit of the ram is activated and the coke cannot be discharged.

In recent coke oven operations, the quality of coke has been improved, the production amount has been secured, the production cost has been reduced, etc., by reducing the water content of the charged coal. However, due to the decrease in moisture, the charge density of coal rises, and the pressure on the furnace wall due to the expansion pressure of coal and the load on the furnace wall when extruding coke rise. The furnace wall may be damaged more than ever. The coke oven, which has been constructed for more than 30 years, has started to stand out, and as the furnace body has deteriorated, the load on the furnace body has increased.

[0004] When extruding coke, part of the pushing force of the extruder ram is applied to the furnace wall as side pressure (for example, Ironmaking Conference Proceedings, AIME, 1).
998, pp. 1155-1159, hereinafter referred to as extrusion side pressure). The extruding side pressure increases as the force required for extruding coke (output of the driving motor of the extruder ram) increases, and sometimes causes troubles such as a hole in a brick or damage to a furnace wall.

[0005] The coke pushing force is determined by the resistance when the coke is moved to the guide vehicle side, and generally,
When the resistance of the furnace bottom, the resistance of the furnace wall, and the rise of coke cake in the furnace height direction during extrusion,
The resistance of the furnace top space surface (the portion that is inside the carbonization chamber and is not in contact with the coal or coke when filled with coal or coke) is considered. Among these, the resistance of the furnace bottom is determined by the weight of the coke to be moved and the coefficient of friction of the furnace bottom, and does not fluctuate significantly during normal operation unless the furnace bottom is damaged or deformed. On the other hand, it is considered that the resistance of the coke oven and the furnace wall surface and the resistance of the furnace top space greatly vary. That is, the resistance that coke receives from the furnace wall surface during extrusion is determined by the frictional force between the furnace wall surface and coke and the smoothness of the furnace wall surface. The smaller the frictional force and the higher the smoothness, the smaller the resistance during extrusion. Here, it is considered that the frictional force between the furnace wall and the coke is determined by the friction coefficient and the extrusion side pressure. Further, the smoothness of the furnace wall surface depends on the state of deposits (carbon) and brick defects existing on the furnace wall surface. Here, the coefficient of friction is considered to be substantially constant once the material is determined, and it is impossible to arbitrarily operate the coke oven in operation. Therefore, factors that control the extrusion force are the extrusion side pressure and the smoothness of the furnace wall surface (the presence or absence of brick loss or adhesion).

It is known that the extrusion side pressure mainly depends on the gap amount between the furnace wall and the coke (Ironmaking
Conference Proceedings, AIME, 1998, page 11
55-1159), the gap amount is determined by the coal expansion pressure during carbonization and the amount of coke burned out. Therefore, it is a factor that can be controlled in coke oven operation by coal blending and furnace temperature management. In addition, with regard to brick defects, the surface smoothness can be maintained by performing thermal spray repair and partial reloading. The attached carbon is generated on the furnace top space surface consisting only of the furnace wall, and is mechanically removed after the coke is discharged, or is burned and removed by introducing an oxygen-containing gas.

By the way, it is unlikely that a brick defect that lowers the smoothness of the furnace wall surface occurs every time carbonization is performed. That is, even if a defect occurs, if the part is repaired, the smoothness is maintained high for several months to several years. on the other hand,
The formation of attached carbon is a phenomenon that always occurs during coal carbonization, and the reduction in smoothness due to carbon attachment is a problem that occurs each time carbonization is performed. Therefore, the increase in the extrusion resistance due to the attached carbon is the most important control item when the furnace operation is performed smoothly.

[0008] Many studies have been made in the past as a method of determining damage such as carbon adhesion to a furnace wall of a carbonization chamber or brick loss. For example, JP-A-63-68690, JP-A-3-146589, and JP-A-8-53676.
Japanese Patent Laid-Open Publication No. HEI 9-214605 proposes a method of determining damage to a furnace wall of a coke oven based on load information applied to a ram drive motor during coke extrusion. In addition, Japanese Patent Application Laid-Open No.
Japanese Patent No. 2490 discloses that a load current is calculated from a difference between a forward load current and a corresponding backward load current of coke pushing of a coke pushing head, and the load current is corrected by a load current value based on coke weight, and the degree of carbon adhesion is accurately determined. A good detection method has been proposed.

These methods are excellent in that information on the furnace wall surface can be obtained every time coke is extruded by utilizing the load resistance applied to the drive motor of the extruder ram which reciprocates in the furnace length direction of the coking chamber. Based on the information, the abnormality of the furnace wall can be detected at an early stage to prevent the damage from expanding. In addition, the fact that the degree of carbon deposition can be detected with high accuracy is achieved by introducing an oxygen-containing gas or the like and performing the operation of removing the deposited carbon efficiently. Are better.

However, in these methods, information can be obtained only by extruding the coke, and it is determined whether or not the coke of the kiln can be smoothly extruded before the extrusion (that is, whether the extrusion load is low). It is impossible to estimate the timing of the extrusion and determine the optimal extrusion timing.

[0011]

In order to avoid an increase in the extrusion resistance due to the adhesion of carbon to the furnace wall and the top space of the furnace, the carbonization must be performed between the extruding of coke and the subsequent charging of coal. One of the countermeasures is to remove indoor carbon accurately. However, if the utilization rate is high,
Despite the increase in the amount of attached carbon, a situation often arises in which it is not possible to secure a removal operation time commensurate with the amount of attached carbon generated in order to secure the amount of skeleton. In such a situation, the push-out resistance increases for the above-mentioned reason, and in the worst case, the jamming occurs.

As a countermeasure in such a case, usually, the furnace lid is closed and the carbonization is continued, and after the coke shrinkage in the furnace width direction is secured, the extruder is again extruded. In the case where extrusion is still impossible, coke discharging work by human power is performed, but it is not preferable because it becomes a poor working environment for handling red hot coke at around 900 ° C.

In the present invention, in order to solve the above-mentioned problems caused by the increase in the extrusion resistance due to the carbon adhering to the furnace wall surface and the furnace top space surface, the properties of the charged coal and the operating conditions of the furnace are determined based on the properties. Predicting the load required to extrude coke with an extruder ram in the kiln before extrusion,
It is an object of the present invention to provide a means for finding optimal extrusion conditions.

[0014]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, in addition to conventionally used coal moisture, volatile matter, temperature, etc., the oil The amount of deposited carbon on the furnace wall and the amount of deposited carbon on the furnace top space surface were estimated using the estimation method, taking into account the addition of dust, dust generation during charging, and the volume of the furnace top space. Have been found to have a good correlation with the maximum value of the extrusion resistance, and have completed the present invention based on the finding. That is, the gist of the present invention is as follows: (1) The load at the time of coke extrusion is expressed by the following equation using the amount of carbon generated on the furnace wall of the coking chamber and the amount of carbon generated on the furnace top space surface of the coking chamber as the following parameters. A) A method for estimating a coke extrusion load, wherein the method is estimated by the equation (A).

[0015]

(Equation 5)

K11: Coefficient (2) The estimated amount of carbon generated on the furnace wall described in (1) is calculated using the oil addition rate to coal, the volatile matter of coal, and the moisture content of coal as follows. The estimated amount of carbon generated on the furnace top space surface obtained by the equation (B) is calculated as follows: the addition rate of oil to coal, the amount of coal charged into the carbonization chamber, temperature, volatile matter of coal, moisture content of coal, A method for estimating a coke extrusion load, wherein the method is obtained by the following equation (C) using the dust generation rate of coal.

[0017]

(Equation 6)

Dw: rate of furnace wall carbon generation (mm / day), k1: coefficient, OL: oil addition rate (mass%) to coal, Tw: furnace wall temperature (K), VM: volatile matter of coal ( Mass%), M: moisture content of coal (mass%).

[0019]

(Equation 7)

Dr: carbon generation rate (mm / day) on the furnace top space surface, W: coal charge (ton), k7 to k10: coefficient, H: coal dust generation rate (mass%), ξ (τ ): Correction factor, τ: Elapsed time since coal charging. (3) The dust generation rate of the coal described in (2) was calculated using an index indicating the crushability of the coal, a flow rate of the generated gas, an index indicating the particle size of the coal, the water content of the coal, and the oil addition rate to the coal. A method for estimating a coke pushing load, characterized by estimating by the following equation (D):

[0021]

(Equation 8)

HGI: Index indicating coal crushability, Gv: Flow rate of generated gas (m / s), Dp: Index indicating coal particle size, k2 to k6: Coefficient. (4) Coke compaction characterized by setting the timing for extruding coke from the coking chamber according to the value of the coke extrusion load estimated using the method according to any one of (1) to (3). Operating method of the coke oven, which prevents the

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several reports have been made on the rate of pyrolytic carbon (adhered carbon) production from coal carbonization gas. (For example, Journal of Fuel Association, Vol. 48, No. 510
No., 1969, pp. 732-737, and Ironmaking
Conference Proceedings, AIME, 1985, p. 35
5-362). Based on these findings, the amount of pyrolytic carbon generated on the furnace wall of the coking chamber can be determined by the properties of the charged coal (volatile matter and moisture), the operating conditions of the coke oven (furnace wall temperature), and the distance between the furnace wall and coke. Can be estimated from the gap amount.

Therefore, the present inventors have reported in the literature (Fuel Association, Vol. 48, No. 510, 1969, pp. 732-73).
The amount of carbon generated was estimated using the following equation described in 7), and based on the above idea, the relationship between the coke extrusion and the load on the drive motor of the extruder ram was investigated.

[0025]

(Equation 9)

Do: carbon formation rate (mm / day), Tw: furnace wall temperature (K), VM: volatile matter (%) of coal, M: moisture content (%) of coal.

The investigation period was about four months, and the furnace operating conditions (furnace wall temperature, total carbonization time, coal charge amount) and the properties of the charged coal (moisture content, volatile matter, oil Are shown in Table 1.

[0028]

[Table 1]

FIG. 4 is a diagram showing a correspondence relationship between an extruding current value (a maximum value of a secondary current generated in a driving motor of an extruder) which is usually used as a scale indicating a load at the time of extruding coke, and a carbon amount estimated by the equation (1). It is shown in FIG. In FIG. 1, the horizontal axis indicates the dates of the surveys in succession,
The left vertical axis indicates the pushing current value, and the smaller the value is, the lower the load required for pushing is, and the more preferable.
The right vertical axis is the estimated carbon amount estimated by applying the daily average value of each item in Table 1 to the expression (1). If the extrusion current and the tendency of the chronological change of the carbon amount match,
The operation of the furnace can be controlled by using the carbon amount obtained by the equation (1) as a measure of the extrusion load. However, as can be seen from FIG. 1, there are few periods (indicated by arrows in the figure) during which the temporal changes seem to coincide during the survey.
It is difficult to use the carbon amount estimated by the equation as a measure of the extrusion load. It is considered that such a discrepancy is due to the fact that carbon deposition has nothing to do with the resistance when extruding coke, or that the estimation of the carbon amount by the equation (1) does not match the actual situation.

As described above, carbon adhesion forms irregularities on the furnace wall, and obviously affects the extrusion resistance. Therefore, the present inventors have estimated that the cause of the discrepancy as shown in FIG. 1 is that the amount of carbon generated during carbonization is estimated only by the three factors of temperature, coal moisture, and coal volatile content, and We considered that not only the carbon on the furnace wall, but also the carbon generated on the furnace top surface might affect the extrusion resistance, and further studied.

In recent coke oven operations, the water content of coal has been reduced in order to secure production and improve quality. As a result, the dusting properties of the coal are increased, and the amount of carryover (fine powder particles transported from the riser pipe to the outside of the carbonization chamber along with the flow of coal gas in the initial stage of carbonization) in the initial stage of carbonization is reduced. Increased. It has been shown that this carryover not only increases the amount of sludge in the tar, but also increases the amount of attached carbon generated from the top space of the carbonization chamber to the riser (for example, Ironmaking).
Conference Proceedings, AIME, 1998, p. 10
41-1051).

Further, in order to increase the selectivity of coal resources, in order to reduce the proportion of caking coal which is liable to become coke and to increase the usage rate of non-fine caking coal, an oil caking filler is used. In addition, the literature (eg, Ironmaking Confere
nce Proceedings, AIME, 1985, pp. 355-36.
As shown in 2), when coal and oil are mixed, the amount of carbon generated during carbonization in a coke oven becomes larger than the amount estimated by evaluating in terms of volatile matter.

Further, in an actual operation, when the pushing load is increased, the amount of coal charged into the coking chamber may be reduced. This is an effective method from the viewpoint of reducing the resistance derived from the friction between the furnace lower surface and coke and reducing the extrusion load, but as will be described later, when the charging amount is reduced, the furnace top space volume is reduced. As a result, the temperature of the furnace top space is increased, and the residence time of coal gas is increased. For this reason, the amount of deposited carbon from the space to the riser increases.

From the above, in order to estimate the amount of carbon deposition suitable for recent coke oven operation, the addition of oil in addition to the three factors of temperature, coal volatiles and coal moisture taken in equation (1) It was concluded that dust generation (or carryover) at the time of charging and the volume of the furnace top space had to be taken into account. The following describes the results of a study on a method for estimating the amount of carbon in consideration of these factors.

First, the effect of adding oil to coal on the amount of deposited carbon will be described with reference to the results of a model experiment. The experimental method is described in the literature (FUEL, Vol. 77,
No. 11, 1998, pp. 1141-1146). That is, the coal mixed with a predetermined amount of oil additives is heated in a container,
From the generated carbonized gas, carbon is generated on the test piece (brick small piece). The carbon generation rate was determined from the amount of the attached carbon, the area of the test piece, and the contact time with the carbonization gas. One example of the obtained result is shown in FIG. In FIG. 2, the horizontal axis is the ratio of oil added to coal, and the vertical axis is
Carbon generation rate (the amount of carbon attached to the brick
Time divided by the time spent hanging in the furnace and the surface area of the brick pieces). It can be seen that the carbon generation rate increases with the oil addition rate. This relationship was formulated by an exponential function, and the following expression was obtained by combining the expression (1) showing the effects of temperature, coal volatile content, and coal moisture content on the carbon generation rate.

[0036]

(Equation 10)

Dw: Carbon generation rate in consideration of addition of oil (mm
/ Day), Tw: furnace wall temperature (K), k1: coefficient (-), OL: oil addition rate (mass%), VM: volatile matter of coal (mass%, according to JIS M8812), M: coal Moisture content (% by mass, according to JIS M8812). Equation (2) is a carbon generation rate in consideration of the temperature, coal volatiles, coal moisture, and the addition rate of oil, and should be applied to carbon generated on the furnace wall of the coking chamber.

On the other hand, as described above, it is necessary to consider the influence of the dust generated at the time of charging and the effect of the volume of the furnace top space on the carbon generated on the furnace top space surface. That is,
The furnace top space carbon includes carryover generated by dust generation at the time of charging, and the carryover amount increases the amount of adhered carbon. Also, since the temperature of the furnace top space changes according to the furnace space volume after charging coal,
There is a problem in applying the temperature used in the equation (2) to the estimation of the rate of formation of carbon in the furnace top space. The results of an examination of the effects of these two factors (carry-over and furnace top space volume) are described below.

First, the effect of carry-over, which is the first factor, on carbon deposition will be described with reference to the results of an investigation in an actual coke oven. When the attached carbon is generated only by the thermal decomposition of the coal carbonization gas, the components contained in the carbon are mainly carbon and hydrogen. However, when it recovered the actual deposited carbon analysis, Al ₂
Metal oxides such as O ₃ , CaO, and SiO ₂ are contained.
When the oxide is contained in the adhered carbon recovered from the carbonization chamber, there are two causes. One is the component in the repair agent used when repairing the brick inside the carbonization chamber, and the other is the ash contained in the charged coal. It is difficult to judge whether the above-mentioned metal oxide contained in the adhered carbon generated on the brick surface in the carbonization chamber is derived from the repair agent or the ash during carryover.

Therefore, the present inventors hanged a small piece of brick as a test piece at a predetermined position in the furnace top space in the carbonization chamber, attached carbon to the test piece under a condition unaffected by the repair agent, and recovered it. The deposited carbon was analyzed. From the obtained analysis values, the contribution ratio of carry-over to the attached carbon was determined by the following equation.

[0041]

[Equation 11]

Ψdepo: ash content in attached carbon (% by mass), Ψcoal: ash content in charged coal (% by mass), VMcoal: volatile component content (% by mass) in charged coal.

FIG. 3 shows the distribution of the carryover contribution ratio in the coking chamber obtained by applying the compositional analysis value of the carbon attached to the brick pieces suspended in the furnace head space of the coke oven to the equation (3).
Shown in In FIG. 3, the vertical axis indicates the carry-over contribution rate calculated by the equation (3), and the higher this value is, the more the carry-over generated at the time of charging is included in the attached carbon. The horizontal axis indicates the position where the small brick pieces were placed in the furnace top space. Here, the base of the riser where coal carbonization gas is concentrated, and the charging inlets provided at five places in the furnace length direction (from the riser (No. 1 to No. 5 are assigned in order from the farthest). From FIG. 3, it can be seen that the carbon deposited on the furnace top surface surface contains a considerable amount of carbon components derived from carryover in addition to the components derived from coal carbonization gas. In particular, in the case of carbon adhering to the riser tube base where the carbonization gas is concentrated, the carry-over ratio exceeds 20% in the measurement example shown in FIG. The above results indicate that in order to accurately estimate the amount of attached carbon generated from the furnace top space to the riser, it is necessary to correctly understand the effect of carryover on the attached carbon generation. Therefore, the results of a study for quantifying the effect of carryover on the carbon adhesion behavior will be described below.

First, the results of an examination of the relationship between the behavior of carryover and the properties of coal will be described. FIG. 4 shows an outline of the experimental apparatus used for the study. A predetermined amount of a measurement sample (coal) 1 is filled in a sample container 2 installed on an acrylic pipe (φ150 × 2000 mm) 6. In a state where air is circulated upward at a predetermined flow rate in the acrylic pipe, the upper slide gate 3 is operated to measure the measurement sample 1.
Is dropped by gravity. Suction blower (not shown) at the same time that most of the sample falls onto the lower slide gate 3
Is operated to take out the scattered particles generated in the acrylic pipe from the scattered particle suction port 5 to the outside. When the flying particles disappear, the suction blower is stopped, the lower slide gate 3 is operated, the remaining sample is stored in the sample receiver 8, and the mass is measured. The mass ratio (%) of the non-recovered sample (sample sucked out of the acrylic container) to the first measurement sample was defined as the dust generation rate of the measurement sample. If the suction amount of the blower is set to the suction gas flow rate in the coking chamber at the time of charging coal in the actual furnace, a value corresponding to carry-over of the actual furnace can be obtained. Considering the type of coal, moisture content, particle size, gas flow rate, and oil addition rate as factors affecting the dust generation rate, tests were performed at the levels shown in Table 2.

[0045]

[Table 2]

Here, the types of coal were distinguished by using a hard globe index (HGI) which is an index of hardness at the time of grinding.
Further, apart from HGI, a mass ratio (%) of coal having a particle diameter of 3 mm or less (hereinafter, referred to as -3 mm%) was used as an index representing the particle size of actually pulverized coal. further,
The component of the oil to be added is not particularly limited, and may be any substance having an effect of compensating the coking properties of coal, such as tar, tar sludge, and other hydrocarbon compounds.

Assuming that the dusting rate of coal is represented by a linear combination of the above-mentioned influence factors, the test results were regression-analyzed by the following equation (4).

[0048]

(Equation 12)

H: Coal dusting rate (% by mass), HGI: Index (−) indicating the pulverizability of coal (JIS M8)
Gv: flow rate of generated gas (m / s) (JIS Z8808)
-3 mm%: mass ratio of coal having a particle diameter of 3 mm or less (mass%), M: moisture content of coal (mass%) (JIS M8812)
OL: oil addition rate to coal (% by mass), k2 to k6: coefficient.

The flow rate of the gas in the carbonization chamber is basically measured at the furnace top space by inserting a flow rate measurement probe from the opening. More specifically, the opening corresponds to a charging port in the upper part of the carbonization chamber and a fire judging port provided in the riser. Of these, there are usually 4 to 5 inlets per carbonization chamber (5 for most carbonization chambers). In addition, the burnout judging port is not always provided in the carbonization furnace, and is installed as necessary. The measurement is any or all of the above-mentioned positions, and it is desirable to measure at all the positions.

FIG. 5 shows the relationship between the calculated value of the dust generation rate according to the equation (4) and the actually measured value. In FIG. 5, the abscissa represents the actually measured values obtained by the above-described experiment, and the ordinate represents k2 to k2 obtained by regression analysis.
This is a value calculated using the coefficient of k6. The correspondence between the two is good, and based on this result, it can be determined that the dust generation rate at the time of charging coal can be estimated by equation (4). In addition, although -3 mm% was used as an index indicating the particle size of the charged coal, the present invention is not particularly limited to this. Any numerical value can be used as long as it correctly represents the particle size composition that varies depending on the degree of water content.

Here, it should be noted that the dust generation rate obtained by the equation (4) is a value immediately after charging coal into the coking chamber.
Generally, as time passes, the dust generation rate decreases. Unless the change over time is known for both the amount of generated gas and the dust generation rate, it is impossible to calculate the carbon generation rate in consideration of the carryover described below.

In this regard, the present inventors have conducted actual furnace measurements and reported results as shown in FIG. 6 (Iron
making Conference Proceedings, AIME, 1998,
Pp. 1041-1051). In FIG. 6, the vertical axis is JI
SZ8808 (Method of measuring dust concentration in exhaust gas, 1
995), and the horizontal axis is the product of the coal moisture (M) and the logarithmic value of the elapsed time (t) from the coal charge. By formulating this relationship, it is possible to estimate a temporal change in the carry-over concentration after charging coal.

Next, the relationship between carryover and the rate of attached carbon generation will be described. Regarding this relationship, a report by the present inventors (FUEL, Vol. 77, No.
11, 1998, pp. 1141-1146). FIG. 7 shows the relationship between the temperature and the carbon generation rate when carryover and coal carbonization gas coexist, and FIG. 8 shows the relationship between the carryover concentration and the carryover concentration. FIG. 7 shows the carry-over concentration in coal dry distillation gas = 20 g / m ³ (Norma
This is the case where the relationship is constant in l). FIG. 7 shows that even when carryover coexists, the attached carbon generation rate changes depending on the temperature. FIG. 8 shows the case where the carry-over concentration is changed when the temperature is constant. It can be seen that the amount of deposited carbon significantly increases as the carry-over concentration increases.

Regarding the effect of the furnace top space volume, which is the second factor, according to the literature (Aromatics, Vol. 41, No. 3, No. 4, 1989, pp. 10-17), the coke oven has the following characteristics. It is stated that the top space temperature rises in proportion to the top space volume. The cause is that when the space volume increases, the exposed area of the furnace wall surface, which is the radiation surface, increases, the radiation amount increases, the ambient temperature rises, and the residence time of the carbonized gas in the space increases, and the temperature increases. To rise. As a result, the reaction rate increases and the amount of deposited carbon increases.

Based on the above findings, the content of obtaining the carbon generation rate equation taking into account the effects of carryover and furnace top space will be described below.

First, a method of considering the influence of the amount of coal charged will be described. As described above, the furnace head space temperature has a fixed relationship with the furnace head space volume. Here, the furnace top space volume is determined by the difference between the carbonization chamber volume and the charged coal volume. Further, since the charged coal volume can be known from the charged coal amount and the bulk density, the furnace top space temperature can be estimated from the charged coal amount. When this relationship is applied to equation (2), the following equation (5) is obtained.
The formula was obtained.

[0058]

(Equation 13)

Do, s: carbon formation rate (mm / day) in consideration of the effect of the oil addition rate to coal and the furnace top space volume, Ts: furnace top space temperature (° C.), W: coal charge (ton) ), K7, k8: coefficient (-).

Next, the effect of carryover was formulated. When the relationship between the carryover concentration and the carbon generation rate shown in FIG. 8 was formulated by an exponential function and applied to the equation (5), the following results were obtained.

[0061]

[Equation 14]

Dr: carbon addition rate (mm / day) in consideration of the oil addition rate to coal, the effect of furnace top space volume and the effect of carryover, OL: oil addition rate to coal (mass%), W: The amount of coal charged to the coking chamber (ton), VM: volatile matter (% by mass) of coal (according to JIS M8812), M: moisture content (% by mass) of coal (JIS M8812)
), H: Coefficient of dust generation (%) determined by equation (4), ξ (τ): Correction coefficient (-), τ: Elapsed time (h) from charging coal, k9, k10: Coefficient.

A supplementary explanation will be given for the correction coefficient ξ (τ). FIG.
As shown in the figure, since the dust generation at the time of charging decreases with the passage of time, Exp (k9 + k10 ×
If the item of H) is used as it is, the dry distillation 1
Calculating the amount of carbon in the cycle,
Significantly higher amounts of carbon give results. Correction factor ξ
(Τ) is a coefficient introduced to solve such a problem, and the elapsed time τ from coal charging (given as a relative value to one cycle of carbonization in order to make dimensionless).
At the same time, it changes in the range of 0 ≦ ξ (τ) <1.

Further, considering the actual coke oven, the temperature, the gas flow rate, and the carry-over concentration change every moment. Therefore, in order to more accurately estimate the carbon amount, the following equation (7) is used. In addition, it is desirable to determine the amount of carbon generated at every minute time and integrate the calculated amount up to the burnout time.

[0065]

(Equation 15)

The reason why the sum is set to the burn-down time is that the amount of the carbonized gas that becomes a carbon source is significantly reduced after the burn-down, and the estimated carbon amount is greatly increased. This is because there is a possibility.

FIG. 9 shows a flow of logic for estimating the pushing load by using the above-described equations. First, the water content M, the volatile content VM, the oil addition rate OL, which is the properties of the charged coal, and the furnace wall temperature Tw, which is the furnace operating condition, are applied to the equation (2) to obtain carbon generated on the furnace wall. The quantity Dw is estimated (arrows 9 and 10 in FIG. 9). Next, the gas flow rate Gv is calculated from the HGI, M, OL and particle size (-3 mm%) of the properties of the coal, the furnace wall temperature and the coal charge W which are the operating conditions of the furnace (arrows 17 in FIG. 18) Or, by actually measuring in the furnace top space and applying the value to equation (4), the dust generation rate H of the coal
Is estimated (arrows 11 and 16 in FIG. 9). This H and O
By applying L, W, VM, and M to the equation (6), the amount of carbon generated on the furnace top space surface is estimated (arrow 19 in FIG. 9).

When estimating the amount of carbon adhering to the furnace wall by the equation (2), if the temporal change of the furnace wall temperature can be obtained as information, the amount of carbon generated for each minute section is calculated in the same manner as in the equation (7). It is desirable to add up. In this case, it is necessary to consider the burnout time, which is the operating condition of the furnace (arrow 15 in FIG. 9). In addition, although -3 mm% was used as the particle size of the coal, it is not particularly limited to this, and the sieve size is 0.3 mm.
Any index can be used as long as it is an index that correctly represents the particle size distribution that varies depending on the type of coal, the degree of pulverization, the water content, and the addition rate of oil, such as the following ratio and the ratio of 0.1 mm or less. Further, as the furnace wall temperature, for example, it is desirable to use a measurement value by a thermometer attached to the ram head of the extruder, but when the measurement system is not installed and the furnace wall temperature cannot be directly measured, Any value may be used as long as the index is related to the temperature change of the furnace wall.For example, the temperature of the combustion chamber is measured with a radiation thermometer or the like, and the temperature estimated by heat transfer calculation based on the value, or It is also possible to use the indicated value of a thermometer installed at a predetermined location of the furnace body for furnace temperature management.

The extrusion load is estimated from the furnace wall carbon amount and the furnace top space carbon amount estimated by these methods (FIG. 9).
The method of arrows 13 and 14) in the middle will be described. The influence of the carbon generated on the furnace top space surface on the extrusion load is that when the coke cake is pushed by the extruder ram,
This is because not only the furnace is compressed in the furnace length direction, but also a swelling in the furnace height direction occurs. Although no quantitative knowledge on the amount of this swelling has been obtained, it is a phenomenon that is routinely observed by visual observation of operators. Therefore, when the amount of coal charged is large or the amount of carbon deposited on the furnace top space is large, the raised coke surface layer and the carbon deposited on the furnace top surface come into contact with each other to increase the extrusion resistance.

It is considered extremely difficult to quantitatively analyze the contribution ratio of the furnace wall carbon and the furnace top carbon to the extrusion resistance. Therefore, the following carbon resistance index was introduced.

[0071]

(Equation 16)

K11: coefficient.

That is, the estimated amount of carbon generated on the furnace wall and the estimated amount of carbon generated on the furnace top space surface have a coefficient k
The value multiplied by 11 was added to define a carbon resistance index, and it was assumed that the index had a certain correspondence with the actual extrusion load. Here, the coefficient k11 was multiplied by the estimated amount of carbon generated on the furnace top surface because the entire amount of carbon generated on the furnace top surface did not contribute to the extrusion resistance, but only the part overlapping with the rise of coke. Is considered to be involved. If the overlap can be estimated, the resistance can be estimated from the contact area and the friction coefficient of both, but it is extremely difficult at present to estimate the amount of coke swelling in the operation of an actual coke oven. Therefore, k11 was introduced as a coefficient in consideration of the resistance due to the interaction between the carbon on the furnace top surface and the raised coke.

There are several methods for determining the coefficient k11. For example, during a certain period, the relationship between the extrusion resistance (actually measured value) and the carbon resistance index (calculated value) shown in the equation (8) is plotted. At this time, the coefficient k11 is selected so that the correlation coefficient between them becomes the highest.

In order to further improve the accuracy, factors involved in estimating the amount of carbon generated on the furnace top space surface, that is, the water content, the volatile content, the oil addition rate, which are the properties of the charged coal, and Grain size and any or all of the coal charge, which is the operating condition of the furnace, are stratified and grouped,
Preferably all stratified, in each group,
The coefficient k11 having the highest correlation coefficient is obtained from the equation (8). Then, in order to actually estimate the extrusion load, first, the amount of carbon generated on the furnace top space surface is estimated. Next, it is determined to which group the estimated value belongs, and the carbon resistance index is calculated using the coefficient k11 having the highest correlation with the corresponding group.

By applying the obtained carbon resistance index to the relationship between the extrusion resistance and the carbon resistance index determined in advance, an estimated value of the extrusion load can be obtained. When the extrusion load can be estimated, the management value of the extrusion load is determined for each furnace group or for each kiln, and the properties of the charged coal and the operating conditions of the furnace can be adjusted in advance so as not to exceed the value. Even if priority is given to ensuring coke quality and production volume and there is not much freedom in changing the conditions, the factors shown in FIG. 9 are optimized by utilizing a control theory such as AI (artificial intelligence). It is possible to In particular, after charging coal, it is impossible to change the coal properties or the amount of coal charged in order to control the extrusion load of the kiln.

Further, it is impractical to change the temperature of the combustion chamber one by one in order to change the furnace wall temperature. The only way to control the extrusion load after charging the coal is to adjust the time from when the fire goes out to when the coke is extruded.
In general, the longer the placing time, the lower the extrusion load, but if it is necessary to secure the production volume, the placing time must be shortened as much as possible, and the load required for extrusion increases. I will. Usually, when the extrusion load is increased, a limiter is operated to prevent the ram drive motor of the extruder from being overloaded and damaged. This limit depends on the capacity of the extruder. Therefore, it is necessary to wait for the coke to be extruded at least until the value becomes equal to or less than the limit value (that is, to increase the setting time). According to the present invention, the waiting time can be accurately predicted, so that it is possible to prevent the occurrence of the pressing jam due to the operation of the overload circuit of the drive motor.

Further, even when the drive motor is not overloaded, if the ram pressing force is high, the pressure on the extrusion side also increases, which may damage the furnace wall. When the limit value of the lateral pressure that damages the furnace wall is determined, the lateral pressure is estimated from the predicted pushing force, and the extrusion is not performed until the estimated value becomes equal to or less than the limit value. Although such a method results in a longer storage time, it is advantageous in terms of the time and labor required for the post-treatment of the occurrence of the jam by preventing the occurrence of the jam.

[0079]

(Example 1) The carbon resistance index was calculated by applying the average data of about four months obtained in the actual coke oven shown in FIG. 1 to the equation (8), and the coke extrusion load was calculated. FIG. 10 shows the result of examining the corresponding relationship with.
Compared with the case of FIG. 1, the temporal relationship between the two is significantly improved. This indicates that the carbon resistance index is suitable for operation control of an actual coke oven as a control index of the extrusion load.

(Example 2) The daily average data for about three months obtained in a period different from that shown in Example 1 was
Calculate the carbon resistance index by applying the formula, and set the load current value (maximum value) applied to the drive motor of the extruder ram from the comparison with the relationship with the extruded load obtained in the past so that the lowering time is set to be stable Was adjusted to set the timing for extruding coke.

FIG. 11 shows the result of comparing the frequency of occurrence of the load current value (maximum value) in a histogram between a period in which the present invention was not applied and a period in which the present invention was applied. (A) is a case where the present invention is not applied, (b) is a case where the present invention is applied,
In both cases, the sampling numbers were the same. In this figure, the horizontal axis indicates the range of the load current value (ampere, A) of the ram drive motor as the pushing load, and the vertical axis indicates the frequency at which the range of the load current value appears. As can be seen from the figure, when the present invention is applied, the load is reduced and the distribution width is narrower than when the present invention is not applied. This indicates that the present invention has stabilized the extrusion load to a low level.

[0082]

According to the present invention, the coke extrusion load (load applied to the drive motor of the extruder ram) can be estimated from the properties of the charged coal and the operating conditions of the furnace. By appropriately controlling the operating conditions of the furnace and the furnace, a load increase during extrusion can be suppressed. As a result, the extrusion side pressure is reduced, and damage to the furnace body can be reduced. In addition, troubles such as jamming (stopping the movement of the ram beam during coke extrusion) can be avoided, and release from manual coke discharging work, which is one of the measures to recover from such troubles, or
During the work, near the both ends of the carbonization chamber, it is possible to prevent the surface temperature of the silica brick from being lowered and the brick from being damaged, so that the economic and technical effects are extremely high.

[Brief description of the drawings]

FIG. 1 is a graph showing a comparison between the amount of carbon deposited on a furnace wall estimated by equation (1) and a load current value (maximum value) applied to a drive motor of an extruder ram.

FIG. 2 is a graph showing a relationship between an oil addition rate and an attached carbon generation rate.

FIG. 3 is a graph showing a carry-over ratio in adhered carbon collected at a predetermined position in a furnace top space.

FIG. 4 is a schematic view of an apparatus for measuring the dust generation rate of coal.

FIG. 5 is a graph showing a relationship between an actually measured value and an estimated value of the dust generation rate.

FIG. 6 is a graph showing the relationship between the change over time of the carry-over concentration and the moisture content of the charged coal.

FIG. 7 is a graph showing a relationship between an attached carbon generation rate and a temperature.

FIG. 8 is a graph showing the relationship between the carry-over concentration and the attached carbon generation rate.

FIG. 9 is an explanatory diagram showing a flow of estimating a coke pushing load according to the present invention.

FIG. 10 shows a carbon resistance index according to the present invention and a load current value (maximum value) applied to a drive motor of an extruder ram.
6 is a graph showing a comparison.

FIG. 11 is a graph showing a comparison of histograms of load current values (maximum values) applied to the drive motor of the extruder ram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Measurement sample 2 ... Sample container 3 ... Slide gate 4 ... Blower suction 5 ... Scattered particle suction port 6 ... Acrylic pipe 7 ... Air suction port 8 ... Sample receiver 9-19 ... Arrow indicating the direction of flow

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Makoto Ando 1-Nishinosu, Oita-shi, Oita-shi, Nippon Steel Corporation Oita Works (72) Inventor Shin Matsuura 20-1 Shintomi, Futtsu-shi, Chiba Japan-made (72) Inventor Tatsuya Kudo 12th Nakamachi, Muroran-shi, Hokkaido F-term in Muroran Works, Nippon Steel Corporation 4H012 EA00 LA03

Claims (4)

[Claims] 1. The load at the time of coke extrusion is estimated by the following equation (A) using the amount of carbon generated on the furnace wall of the coking chamber and the amount of carbon generated on the furnace top space of the coking chamber as parameters. Method for estimating the coke extrusion load. (Equation 1) k11: coefficient. 2. The following formula (B) is used to calculate the estimated amount of carbon generated on the furnace wall according to claim 1 using an oil addition rate to coal, volatile matter of coal, and a moisture content of coal. The estimated amount of carbon generated on the furnace top surface is calculated based on the oil addition rate to coal, the amount of coal charged into the coking chamber, temperature, coal volatiles, coal moisture content, and coal dust generation. Using the rate
A method for estimating a coke pushing load, which is obtained by the following equation (C). (Equation 2) Dw: generation rate of furnace wall carbon (mm / day), k1: coefficient, OL: oil addition rate to coal (mass%), Tw: furnace wall temperature (K), VM: volatile matter of coal (mass%) , M: Coal moisture content (mass). (Equation 3) Dr: carbon generation rate (mm / day) on the furnace top surface, W: coal charge (ton), k7 to k10: coefficient, H: coal dust rate (mass%), ％ (τ): correction Coefficient, τ: Time elapsed since coal loading. 3. The dust generation rate of the coal according to claim 2, wherein the index indicates the pulverizability of the coal, the flow rate of the generated gas, the index indicating the particle size of the coal, the moisture content of the coal, and the oil addition rate to the coal. A method for estimating a coke extrusion load, wherein the estimation is performed by the following equation (D). (Equation 4) HGI: index indicating the crushability of coal, Gv: flow rate (m / s) of generated gas, Dp: index indicating the particle size of coal, k2 to k6: coefficients. 4. A compaction of coke characterized by setting a timing for extruding coke from a coking chamber according to a value of a coke pushing load estimated by using the method according to any one of claims 1 to 3. To prevent coke oven operation.