JP5835075B2 - Method for estimating inflation pressure - Google Patents

Description

  The present invention relates to a technique for estimating the expansion pressure of coal charged in a coke oven.

  In the process of producing coke by carbonizing coal in a coke oven, the coal expands when heated and exerts pressure on the coke oven wall. This pressure is generally called expansion pressure. Yes. If this expansion pressure becomes abnormally high, the furnace wall of the coke oven will be damaged, making it impossible to operate, or the extrusion load when pushing coke out of the furnace from the carbonization chamber will increase, adding excessive load to the furnace wall. This causes damage to the furnace wall. For this reason, it is an important issue to manage the expansion pressure below the allowable limit value for coke oven damage in the operation of the coke oven. In particular, coke ovens have become aging in recent years, and the allowable limit value is lowered due to a decrease in furnace body strength. In addition, the introduction of coal pretreatment technology such as the humidity-controlling coal method in recent years has led to the introduction of coal into the coke oven carbonization chamber. As the bulk density rises and the expansion pressure tends to increase, expansion pressure management has become an increasingly important issue for extending the life of coke ovens.

In order to avoid damage to the coke oven, it is necessary to actually distill the coal in the test furnace and measure the expansion pressure before using it in the coke oven. In general, Koppers and Jenkner (H. Koppersand A. Jenkner, Fue
l, 10 (1931), 232, H.Koppers and A.Jenkner, Fuel, 10 (1931), 273) is used for the movable wall furnace (special test distillation furnace with movable wall on one side) The expansion pressure measured in this movable wall furnace is 10 to 15 kPa as the allowable limit value of the furnace body strength of the coke oven.

  However, this test carbonization furnace is very expensive and requires a large amount of coal sample (about 400 kg), which is not a simple measurement method. In addition, the reproducibility of the measurement results is poor, and a rapid response cannot be made when changing the blending of raw coal or changing the operating conditions of the coke oven. Therefore, a method for estimating the expansion pressure by a simple method without actually measuring the expansion pressure of coal in a test carbonization furnace has been proposed.

  Patent Document 1 adjusts the degree of coal coalization and the amount of inert components based on a method of estimating expansion pressure from the degree of coalification and the amount of inert components represented by volatile matter, carbon content, vitrinite average reflectance, and the like. And the control method of coal expansion pressure which controls so that expansion pressure becomes below an allowable limit value is indicated. Patent Document 2 measures the gas permeability coefficient of a coal bed in a softened and melted state, or determines the gas from a coal property (the amount of inert components and the maximum fluidity in the coal structure) or an estimation from dry distillation conditions. Using this gas permeability coefficient, the thickness in the furnace width direction of the coal bed in the softened and melted state, and the rate of generation of pyrolysis gas per unit volume from the softened and melted layer, the time of expansion pressure in the coal dry distillation process is estimated. The change is estimated.

JP-A-4-306294 JP-A-5-340937

  However, as disclosed in Patent Document 1, the value estimated by the method of estimating the expansion pressure from the degree of coalification and the amount of inert components represented by the volatile matter, the carbon content, the vitrinite average reflectance, etc., and the actual measurement It was found that there was incoming coal that deviated from the value.

  Further, using the gas permeation coefficient, the furnace width direction thickness of the coal bed in the softened and melted state, and the pyrolysis gas generation rate per unit volume from the softened and melted layer as disclosed in Patent Document 2, The value estimated by the method for estimating the expansion pressure in the process is also the estimated value of the measured value and the expansion pressure when the gas permeability coefficient is estimated using the coal properties (the amount of inert components in the coal structure and the maximum fluidity). It was found that there are coals that deviate.

An object of the present invention is to provide a method for accurately estimating an expansion pressure by an extremely simple method without actually measuring the expansion pressure of coal using a vitrinite reflectance distribution.

  As a result of earnestly examining the above problems, the present inventor has found that the vitrinite reflectance distribution has a plurality of peaks as a cause of reducing the estimation accuracy of the expansion pressure. FIG. 1 shows the vitrinite reflectance distribution of coal coal having a plurality of peaks in the vitrinite average reflectance. The horizontal axis represents the vitrinite reflectance and the vertical axis represents the ratio (volume%). The vitrinite reflectance distribution in FIG. 1 is divided into a high reflectance portion and a low reflectance portion.

  In this case, when the vitrinite average reflectance is obtained by the method disclosed in Patent Document 1, the difference between the vitrinite average reflectance and each peak value becomes large, and the vitrinite average reflectance becomes a value deviated from the representative characteristics of coal. End up. That is, as shown in FIG. 2, when the vitrinite average reflectance of the incoming coal has only one peak, the vitrinite average reflectance represents the representative properties of the incoming coal. The expansion pressure can be estimated with high accuracy.

However, it has been found that in the case of the coal as shown in FIG. 1, the expansion pressure cannot be accurately estimated from the vitrinite average reflectance because the vitrinite average reflectance deviates from the representative properties of the coal.

In addition, in the method disclosed in Patent Document 2, when the coal properties (the amount of inert components in the coal structure and the maximum fluidity) are used, only the average value of the entire incoming coal, the maximum fluidity, can be obtained. Therefore, it has been found that the expansion pressure cannot be estimated with high accuracy in the case of incoming coal as shown in FIG.

In order to solve the above problems, the present inventor
(1) The reflectance of the vitrinite structure and the total amount of the inert structure of the coal charged in the coke oven are measured, and the measurement result and the vitrinite obtained in advance using one coal as the reflectance of the vitrinite structure. In the method of estimating the expansion pressure of the coal charged into the coke oven from the correlation between the reflectance of the tissue and the total amount of inert structure and the expansion pressure, the coal charged into the coke oven has a vitrinite structure. The reflectance includes a plurality of peaks, and the reflectance distribution corresponding to each of the peaks is made a normal distribution, and the average value of the reflectance in each normal distribution and the total amount of inert tissue are used. The expansion pressure corresponding to each of the peaks is estimated, and the vitrinite structure included in each peak includes the entire vitrinite structure included in the coal. With a ratio, by weighted averaging of each inflation pressure that the estimated and created a method for estimating the expansion pressure of the entire coal.

(2) In the method for estimating the expansion pressure of the (1), the total amount of reflectance distribution and inert tissue of the vitrinite tissue can be measured by methods standard in JIS M88 16.

(3) In the method for estimating the expansion pressure of (1) above, the reflectance distribution of the vitrinite structure and the total amount of inert structure can be measured by a coal structure automatic analysis method having Steps A to C.
Step A: Visible light is irradiated to the target coal, and the reflectance is measured.
Step B: The measurement points where the difference in reflectance between two points close to each other so that the vitrinite structure can be measured are within a certain range are counted as the vitrinite structure.
Step C: Measurement points where the difference in reflectivity between the two adjacent points is outside the predetermined range and the reflectivity is higher than a predetermined value are recognized as an inert tissue and aggregated.

  For example, a method developed by Kojima (Iron and Steel vol.64, No.12 pp.1661-1670 (1978)) is recommended as the above-described automatic measurement method of coal structure. Incidentally, “between two adjacent points” and “within a certain range” described in the above-mentioned B process, “the difference in reflectance between two points close to each other so that the vitrinite structure can be measured is within a certain range” will be described.

The vitrinite structure is measured using the fact that it is optically homogeneous and exists in a larger form than other structures, that is, it uses the fact that there is almost no difference in reflectance between two adjacent points. Is measured. Therefore, the distance between “adjacent two points” may be appropriately set as long as the vitrinite structure can be measured, and may be 10 μm, for example.

In addition, “within a certain range” means that in the case of a vitrinite structure, as described above, it is optically homogeneous and exists in a larger form than other tissues. is there. However, when one of the two points is applied to another tissue, the same reflectance is not obtained, and a slight difference may occur. Therefore, a “certain range” may be set based on past data or the like and allowable measurement accuracy. For example, the difference in reflectance between two points may be within 0.075%.

  In addition, the “predetermined value” in the description of “the measurement point where the reflectance is higher than the predetermined value as an inert structure” in the step C may be a reflectance that represents a vitrinite structure. For example, an average reflectance is used. It is preferable.

  According to the present invention, it is possible to suppress the vitrinite average reflectance from deviating from the actual coal properties. As a result, the estimation accuracy of the expansion pressure can be improved.

It is a vitrinite reflectance distribution of incoming coal consisting of simple coals A and B. It is a vitrinite reflectance distribution of incoming coal consisting of a kind of simple coal. 2 is a normal distribution obtained by separating the vitrinite reflectance distribution of FIG. 1 into waveforms. It is the graph which showed the relationship between expansion pressure and vitrinite reflectance. It is the graph which showed quantitatively the deviation | shift amount of the expansion pressure estimated by the method of the Example, and the measurement expansion pressure. It is the graph which showed quantitatively the deviation | shift amount of the expansion pressure estimated by the method of the comparative example, and measurement expansion pressure.

  The method for estimating the expansion pressure of coal according to this embodiment will be described in detail. In recent years, the development of new coal mines has been active as the price of coal has soared, but there are some new coals (corresponding to incoming coal described later) that have multiple peaks in the vitrinite reflectance distribution. understood.

  The reason for this is not clear, but when the amount of coal mined from one mining site is small, the solid coal A mined in this mining site and the solid coal B mined in the other mining site It is conceivable that the vitrinite average reflectivity varies depending on the coal layer, even when they are mixed in a charcoal factory or shipping port, or even in the same mining site.

  As described above, the coal having the vitrinite reflectance distribution having a plurality of peaks has a problem that the estimation accuracy of the expansion pressure is lowered. Therefore, the coal in the present embodiment is for coal having a plurality of peaks in the vitrinite reflectance distribution.

First, the reflectance distribution of the vitrinite structure contained in the incoming coal is measured. Here, the measuring method of the reflectance distribution, since it is prescribed in JIS M88 16, a detailed description thereof will be omitted. In addition, as above-mentioned, you may measure a reflectance part with the coal structure automatic analysis method which has A process-C process. In the coal coal of this embodiment, the reflectance distribution has two peak values as shown in FIG. 1, the waveform on the right side in the figure corresponds to the high reflectance part, and the waveform on the left side in the figure is Corresponds to the low reflectivity part.

  Next, the data of the reflectance distribution in FIG. 1 is processed to separate the waveform into a normal distribution corresponding to the high reflectance portion and a normal distribution corresponding to the low reflectance portion. Data processing is executed by a computer reading a known program recorded in software. FIG. 3 shows a normal distribution after waveform separation. The waveform on the right side corresponds to the high reflectance portion, and the waveform on the left side corresponds to the low reflectance portion.

  Next, based on FIG. 3, the vitrinite average reflectivity of the high reflectivity portion and the low reflectivity portion is obtained, the expansion pressure is estimated by the method described later using the obtained vitrinite average reflectivity, and the received coal The weight of the expansion pressure estimated by the content ratio with respect to the whole vitrinite structure contained in is averaged to obtain the expansion pressure in the entire coal. That is, the vitrinite average reflectance of this embodiment is not simply obtained from the vitrinite reflectance distribution as in the prior art, but the vitrinite reflectance distribution corresponding to each peak is normalized, and the vitrinite reflectance of each peak is normalized. It is obtained by averaging the vitrinite reflectance distribution for each distribution.

  In the present embodiment, the vitrinite average reflectance of the high reflectance portion is 1.45 (%), and the vitrinite average reflectance of the low reflectance portion is 1.02 (%). Moreover, the content ratio of the vitrinite structure contained in the high reflectivity portion of the high reflectivity portion and the low reflectivity portion contained in the received coal is 59.1 (volume%), and the vitrinite structure contained in the low reflectivity portion. The content ratio of is 40.9 (volume%). In addition, the vitrinite average reflectance of the incoming coal simply averaged without waveform separation is 1.28 (%).

  Next, by applying the vitrinite average reflectance obtained by waveform separation to the graph of FIG. 4 (corresponding to the correlation), the expansion pressure is obtained, and the estimated expansion is determined by the content ratio of each peak with respect to the entire vitrinite structure. The expansion pressure of the entire coal can be estimated by averaging the pressures.

Here, FIG. 4 shows the correlation between the reflectance and the expansion pressure. The correlation varies depending on the total amount of inert structure contained in the coal coal (hereinafter referred to as the total inert amount). In FIG. 4, only the cases where the total inert amount is 15%, 25%, and 35% are illustrated, but other total inert amounts can be added as appropriate. Note that the total inert amount when measuring the vitrinite reflectance distribution can be obtained (see JIS M88 16). In addition, as described above, the total inert amount may be measured by an automatic coal structure analysis method including Steps A to C.

  The graph of FIG. 4 can be acquired by conducting a test using a test coke oven in advance. In this case, it is necessary to select coal having one peak as the reflectance of the vitrinite structure. Incidentally, if the peak of reflectance of the vitrinite structure is one coal, various types of coal can be used. In the present embodiment, coal was charged into a test coke oven having a 420 carbonization furnace having a furnace width of 420 mm, and the expansion pressure was measured. Such a measurement was performed using a plurality of types of coal.

Coal pulverized with a pulverized particle size such that particles of 3 mm or less were 85 mass% was charged into a test coke oven. The charging density was set to 0.85 t / m ³ on a dry coal basis, and the water content was set to 3% by mass. The graph of FIG. 4 was obtained by arranging the measured expansion pressure according to the vitrinite average reflectance of coal, the total inert amount, and the expansion pressure.

  Further, even when there are three or more reflectance peaks of the vitrinite structure of the incoming coal, the expansion pressure can be accurately estimated by calculating the vitrinite average reflectance using the above method.

実施例１では、上記実施形態と同様の入荷炭を使用した。実施例２、４では、石炭のビトリニット組織の反射率のピークが３つの入荷炭を使用した。Ｒｏ１〜Ｒｏ３は、各ビトリニット反射率のピークのビトリニット平均反射率を示している。割合１〜３は、入荷炭に含まれるビトリニット組織全体を１００体積％としたときに各ピークに含まれるビトリニット組織の割合を示している。実施例３、５では、石炭のビトリニット組織の反射率のピークが２つの入荷炭を使用した。 Next, the present invention will be described more specifically with reference to examples. Table 1 shows the expansion pressure estimated by the estimation method of the example. Table 2 shows the expansion pressure estimated by the estimation method of the comparative example. Table 3 shows the expansion pressure estimated by the estimation method of the reference example.

In Example 1, the incoming coal similar to that in the above embodiment was used. In Examples 2 and 4, coal with a peak of reflectance of the vitrinite structure of coal was used. Ro1 to Ro3 indicate the vitrinite average reflectance at the peak of each vitrinite reflectance. Proportions 1 to 3 indicate the proportions of the vitrinite structure contained in each peak when the entire vitrinite structure contained in the incoming coal is 100% by volume. In Examples 3 and 5, coal with a peak of reflectance of the vitrinite structure of coal was used.

  Comparative Examples 1-5 used the same arrival coal as Examples 1-5, respectively. In Examples 1 to 5, the vitrinite average reflectance of each vitrinite reflectance peak was measured by the method of the above embodiment. In Comparative Examples 1 to 5, the conventional method, that is, the vitrinite average reflectance of incoming coal was measured without waveform separation of the obtained vitrinite reflectance distribution. In Reference Examples 1 to 6, an incoming coal with a peak reflectance of the vitrinite structure of coal was used. In Reference Examples 1 and 4, the same incoming coal was used. In Reference Examples 2 and 5, the same incoming coal was used. In Reference Examples 3 and 6, the same incoming coal was used. In Reference Examples 1 to 3, the vitrinite reflectance distribution of incoming coal was normalized by the same method as in the example, and the vitrinite average reflectance was calculated. In Reference Examples 4 to 6, the vitrinite average reflectance of incoming coal was measured by the same method as in the comparative example.

  Compared with Example 1 and Comparative Example 1, in Example 1, the difference between the measured value and the estimated value was only 4.9 (kPa), but in Comparative Example 1, the difference between the measured value and the estimated value. Increased to 31.1 (kPa). Compared with Example 2 and Comparative Example 2, in Example 2, the difference between the measured value and the estimated value was only 4.4 (kPa), but in Comparative Example 2, the difference between the measured value and the estimated value. Increased to 14.7 (kPa). Compared with Example 3 and Comparative Example 3, in Example 3, the difference between the measured value and the estimated value was only 4.9 (kPa), but in Comparative Example 3, the difference between the measured value and the estimated value. Increased to 34.4 (kPa). In comparison with Example 4 and Comparative Example 4, in Example 4, the difference between the actual measurement value and the estimated value was only 4.1 (kPa), but in Comparative Example 4, the difference between the actual value and the estimated value. Increased to 29.2 (kPa). In comparison with Example 5 and Comparative Example 5, in Example 5, the difference between the measured value and the estimated value was only 2.5 (kPa), but in Comparative Example 5, the difference between the measured value and the estimated value. Increased to 9.5 (kPa). From these results, it was proved that the estimation accuracy of the expansion pressure was improved by using the expansion pressure estimation method of the present invention.

  Even when the method of the present invention is applied to estimate the expansion pressure of incoming coal in which the reflectance peak of the vitrinite structure of the coal is one with reference to Reference Example 1 and Reference Example 4, Even if the method was applied, it was proved that there was no big difference in the estimation accuracy of the inflation pressure. Even when the method of the present invention is applied to estimate the expansion pressure of incoming coal with one peak of reflectivity of the vitrinite structure of coal with reference to Reference Example 2 and Reference Example 5, Even if the method was applied, it was proved that there was no big difference in the estimation accuracy of the inflation pressure. Even if the method of the present invention is applied to estimate the expansion pressure of coal with a peak of reflectivity of the vitrinite structure of coal with reference to Reference Example 3 and Reference Example 6, Even if the method was applied, it was proved that there was no big difference in the estimation accuracy of the inflation pressure.

  FIG. 5 is a graph quantitatively showing the amount of deviation between the expansion pressure estimated by the methods of Examples and Reference Examples 1 to 3 and the measured expansion pressure, the horizontal axis is the estimated expansion pressure, and the vertical axis is the measured expansion. Pressure. FIG. 6 corresponds to FIG. 5 and is a graph quantitatively showing the amount of deviation between the expansion pressure estimated by the methods of the comparative example and the reference examples 4 to 6 and the actually measured expansion pressure. As is clear from these figures, the estimated values of Examples and Reference Examples 1 to 3 are plotted close to the actually measured values, and it can be seen that the estimation accuracy of the expansion pressure is extremely high.

According to the present invention, the expansion pressure can be accurately measured. This makes it possible to estimate the expansion pressure before charging coal into the actual furnace carbonization chamber, and to avoid furnace wall damage due to the expansion pressure. As a result, the cost for repairing the coke oven wall can be reduced and the lifetime of the furnace can be extended, and the economic effect is great.

In addition, normally, 10-15 kPa at the expansion pressure is the allowable limit value from the strength of the coke oven body, but according to the present invention, coal blending conditions can be accurately set below the allowable limit value, Costs can be reduced by expanding the types of coal that can be used and reducing the use of high-quality coal.

Claims (3)

The reflectivity of the vitrinite structure and the total amount of the inert structure of the coal charged in the coke oven are measured, and this measurement result and the reflectivity of the vitrinite structure obtained in advance using one coal as the reflectivity of the vitrinite structure are measured. In the method of estimating the expansion pressure of the coal charged into the coke oven from the correlation between the rate and the total amount of inert structure and the expansion pressure, the coal charged into the coke oven is expressed as the reflectance of the vitrinite structure. A plurality of peaks are included, and the reflectance distribution corresponding to each peak is made a normal distribution, and the average value of the reflectance and the total amount of inert tissue in each normal distribution are used to correspond to each peak. Each expansion pressure is estimated, and the vitrinite structure included in each peak includes the entire vitrinite structure included in the entire coal. With a ratio, by weighted averaging of each inflation pressure the estimated, a method for estimating the expansion pressure of the entire coal. The total amount of the reflectance distribution and inert tissue of the vitrinite tissue, the method of estimating the expansion pressure of claim 1, characterized in that it is determined by methods standard in JIS M88 16. The method for estimating an expansion pressure according to claim 1, wherein the reflectance distribution of the vitrinite structure and the total amount of the inert structure are measured by a coal structure automatic analysis method having steps A to C.
Step A: Visible light is irradiated to the target coal, and the reflectance is measured.
Step B: Measurement points in which the difference in reflectance between two points close to each other so that the vitrinite structure can be measured are within a certain range are counted as a vitrinite structure.
Step C: Measurement points where the difference in reflectivity between the two adjacent points is outside the predetermined range and the reflectivity is higher than a predetermined value are recognized as an inert tissue and aggregated.

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