JP6879020B2 - How to estimate coke shrinkage - Google Patents

Description

The present invention relates to a method for estimating the coke shrinkage rate when coal is carbonized under predetermined conditions. Specifically, for example, the particle size of coke obtained by carbonizing coal can be predicted, or the strength of coke can be predicted. The present invention relates to a method for estimating the coke shrinkage rate used in the case of predicting.

In order to further improve the efficiency of blast furnace operation, it is necessary to stabilize the strength and particle size of coke obtained by carbonization of coal, that is, to enable the production of coke with the target strength and particle size. It has been demanded. In addition, in order to reduce the production cost of coke, it is necessary to use as much low-grade low-grade coal as possible, such as non-slightly caking coal. However, as the proportion of these coals in coking coal increases, coke grains are used. It is more important to predict the particle size and strength of the obtained coke in advance because the diameter decreases and the volume-destroying powder ratio increases.

^{Of these, it is known that the drum strength index DI 150} ₁₅ , which is one of the indexes of coke strength, can be expressed as follows in estimating the strength of coke (see, for example, Patent Document 1).
DI ¹⁵⁰ ₁₅ = DI ¹⁵⁰ ₆ − DI ¹⁵⁰ _6-15
That is, in Patent Document 1, when coke is obtained from a blended coal containing a high-coalization degree coal and a low-coalization degree coal, the drum strength index DI ¹⁵⁰ _{15 is set} to the surface breaking strength DI ¹⁵⁰ ₆ and the volume breaking powder. The method of estimating the rate DI ¹⁵⁰ _6-15 separately is disclosed, and the method of estimating the volume destruction powder rate DI ¹⁵⁰ _6-15 is to estimate the Vitrinit average reflectance Ro and low coal of the high coal conversion coal to be mixed. The blending ratio of coal is used. Here, the drum strength index DI ¹⁵⁰ ₁₅ indicates the mass ratio of 15 mm or more after impact specified in JIS K2151.

In addition, the volumetric fracture powder ratio DI ¹⁵⁰ _6-15 ^{is estimated from the solidification temperature of the blended coal, and the surface fracture strength DI 150} ₆ is calculated from the weighted average of the expansion ratio or specific volume of each coal constituting the blended coal by the blending ratio. A method of estimating and estimating the strength of coke based on these (see Patent Document 2) is also known.

On the other hand, it is known that the particle size of coke can be estimated based on, for example, the following formula (see Patent Document 3).
Coal particle size of compounded coal = a + b × coke shrinkage rate of compounded coal In Patent Document 3, coke is produced using compounded coal in various formulations, and the coke particle size is measured. The coke shrinkage rate of each coal contained in is measured, and the coke shrinkage rate of each coal compound is calculated by weighted averaging according to the compounding ratio of each coal, and the coke grains of each compound coal thus obtained are calculated. It is assumed that the coefficients a and b are determined by a method such as regression analysis based on the measured diameter value and the calculated coke shrinkage rate.

Here, the particle size and volume breaking powder ratio of coke are determined due to macrocracks on the order of cm in the coke mass. In general, when coal is carbonized, thermal decomposition and thermal polymerization reaction of an organic polymer structure occur, and various physical phenomena occur accordingly. That is, coal softens and melts from around 400 ° C., particles adhere to each other to form a porous mass, resolidify at around 500 ° C., and then shrink to form coke having a more dense structure. At this time, since there is a temperature distribution in the width direction of the carbonization chamber, it is considered that thermal stress is generated due to the strain of shrinkage and macrocracks are formed. Therefore, coal is used to accurately estimate the strength and particle size of coke. It is necessary to understand the coke shrinkage rate in the shrinkage process after resolidification.

Patent Document 3 above discloses a method for measuring this coke shrinkage rate. That is, in Patent Document 3, the coal is heated to a temperature T (° C.) equal to or higher than the resolidification temperature of coal, and the volume difference or length difference of the contents between the resolidification temperature and the temperature T is the volume or length at the resolidification temperature. The value divided by the above is defined as the coke shrinkage rate at the temperature T of the coke produced from the coal. Specifically, coal is charged into the internal thin tube of the sample tube having a double structure of an internal thin tube provided with a plurality of ventilation holes and an external thin tube, and a piston is placed on the internal thin tube to raise the temperature at a predetermined temperature. The vertical displacement of the piston with respect to the heating temperature is measured, and the coke shrinkage rate is obtained based on the piston height at the resolidification temperature and the piston height at the temperature T.

According to such a method, the coke shrinkage rate, which is the cause of volume fracture and cracks that control the coke particle size, can be directly measured. However, with this method, depending on the type of coal, the piston may be fixed by the molten coal or tar, so that the measurement may not be correct. Further, since the device itself is special, there is a problem that the coke shrinkage rate cannot be measured at any time.

On the other hand, there is a report focusing on the relationship between the properties of coal and the coke shrinkage rate (see Non-Patent Document 1). In this non-patent document 1, the coke shrinkage rate is determined by the method described in the above patent document 3, and it is confirmed that the coke shrinkage rate and the particle size of coke have a correlation. We are also investigating the relationship between the coke shrinkage rate and the volatile content of coal (VM) and the relationship between the coke shrinkage rate and the degree of coalification, but no significant results were found. It is said that the coke shrinkage rate cannot be determined only by the degree of conversion.

By the way, regarding the contraction of coke, there are some that are defined by different physical quantities of interest. For example, in Japanese Patent Application Laid-Open No. 2013-21683 (Patent Document 4), the amount of shrinkage of coke is defined as the gap (clearance) formed between the coke after carbonization and the brick wall of the coke oven. In addition to the coke shrinkage rate described above, this shrinkage is affected by at least various factors such as temperature distribution and expansion pressure, and is different from the coke shrinkage rate targeted by the present invention. is there.

Japanese Unexamined Patent Publication No. 2005-194358 Japanese Unexamined Patent Publication No. 9-263764 Japanese Unexamined Patent Publication No. 2005-223349 Japanese Unexamined Patent Publication No. 2013-216813

Seiji Nomura and Takashi Arima (2013). Effect of coke contraction on mean coke size. Fuel, 105, 176-183.

As described above, in order to further improve the estimation accuracy of coke strength and particle size, it is extremely important to grasp the coke shrinkage rate in the shrinkage process after coal solidification. According to the method described in Patent Document 3, the coke shrinkage rate at the temperature T when heated to a temperature T equal to or higher than the resolidification temperature of coal can be directly measured, but a special device must be used. Also, it may be difficult to measure depending on the coal type. On the other hand, a technique for estimating the coke shrinkage rate by process analysis using the properties of coal by industrial analysis such as volatile matter of coal and elemental analysis has been developed, but sufficient accuracy has not been obtained. It cannot be said that it has been established yet.

Therefore, as a result of diligent studies to solve these problems, the present inventors have made a hydrocarbon-based gas having 2 to 4 carbon atoms among the gases (carbonization gas) generated when coal is heated. We have newly found that C2-4 gas, which is C2-4 gas, has a correlation with the coke shrinkage rate, and by utilizing this relationship, it is possible to estimate the coke shrinkage rate, and thus the present invention has been completed.

Therefore, an object of the present invention is to provide a method capable of estimating the coke shrinkage rate more easily and without depending on the coal type.

That is, the gist of the present invention is as follows.
(1) Coal is placed in a container and heated to a temperature T equal to or higher than the resolidification temperature of coal, and the volume difference or length difference of the contents between the resolidification temperature and the temperature T is determined by the volume or length at the resolidification temperature. It is a method of estimating the coke shrinkage rate at the temperature T of the coke produced from the coal, which is expressed by the divided value.
Of the gases generated when coal is heated at a predetermined temperature rise rate, C2-4 gas, which is a hydrocarbon-based gas having 2 to 4 carbon atoms, is measured, and the maximum amount generated in this temperature rise heating measurement. the C2-4 gas generation amount V ₁ of the at temperatures T ₁ to become seeking (provided that T 1 _<T), based on the obtained C2-4 gas generation amount V _1, at a temperature T of the coal A method for estimating a coke shrinkage rate, which comprises estimating the coke shrinkage rate of.
(2) Coal is placed in a container and heated to a temperature T equal to or higher than the resolidification temperature of coal, and the volume difference or length difference of the contents between the resolidification temperature and the temperature T is determined by the volume or length at the resolidification temperature. It is a method of estimating the coke shrinkage rate at the temperature T of the coke produced from the coal, which is expressed by the divided value.
C2, which is a hydrocarbon-based gas having 2 to 4 carbon atoms, among the gases generated when the coal is heated at a predetermined temperature rise rate for a plurality of test coals having a known coke shrinkage rate at a temperature T in advance. -4 Gas is measured, and C2-4 gas generated amount V _{1 at the temperature T 1} at which the generated amount is maximized in this heating and heating measurement is obtained (however, T ₁ <T), and each test is performed. advance to obtain the correlation equation between C2-4 gas generation rate V ₁ and the coke shrinkage use coal,
For coal coke shrinkage unknown at the temperature T, the generation amount of C2-4 gas in its Atsushi Nobori heating measurement based on ₁ 'C2-4 gas generation amount V at _1' a temperature T that maximizes (where T 'is a _{1 <T),} the method of estimating the coke shrinkage and estimates coke shrinkage from the correlation equation.
(3) the in place of C2-4 gas generation amount V _1, on the basis of the temperatures T ₁ when measuring the amount of generated C2-4 gas C2-4 gas accumulated generation amount V ₂ of up to temperature T ₂ (However, T ₁ <T ₂ ≤ T), the method for estimating the coke shrinkage according to (1) or (2) for estimating the coke shrinkage at the temperature T of the coal.
(4) The method for estimating the coke shrinkage rate according to any one of (1) to (3), wherein the temperature T is the carbonization temperature when coke is obtained from coal.
(5) The method for estimating the coke shrinkage rate according to (3) or (4), _{wherein the temperature T 2 is the temperature T.}
(6) The coke shrinkage rate is measured by using a sample tube having a double structure of an internal thin tube and an external thin tube provided with a plurality of vents as a container for coal, and the sample. Coal is charged into the pipe, a piston is placed and heated at a predetermined temperature rise rate, and the vertical displacement of the piston with respect to the heating temperature is measured to measure the height of the piston at the resolidification temperature of coal and the height of the piston at temperature T. The method for estimating the coke shrinkage rate according to any one of (1) to (5), which is calculated based on Sato.

According to the present invention, the coke shrinkage rate can be estimated more easily with any coal. In particular, if a correlation equation is obtained in advance between the amount of C2-4 gas generated when coal is heated to a predetermined temperature and the coke shrinkage rate, and this correlation equation is used, the coke shrinkage rate is unknown. It will be possible to estimate it accurately for coal.

In this way, by being able to estimate the coke shrinkage rate for general purposes, it can be used, for example, to calculate (estimate) the particle size and volume breakdown of coke obtained by carbonizing coal. , The accuracy can be improved, the efficiency and stabilization of blast furnace operation can be further improved, including the prediction of coke strength, and the use of relatively inexpensive coal such as non-slightly caking coal has increased. It is extremely useful in the production of coke for blast furnaces.

FIG. 1A is an overall schematic explanatory view of an apparatus (high temperature dilatometer) for measuring the coke shrinkage rate, and FIG. 1B is an explanatory view showing a state in which a sample (coal) is charged into a sample tube. 1 (c) is a plan sectional view of the internal capillary tube. FIG. 2A shows the relationship between the sample length and the temperature in the measurement of the coke shrinkage rate, and FIG. 2B is a partially enlarged version of FIG. 2A. Further, FIG. 2C shows the relative length calculated at each temperature with the sample length at the resolidification temperature as 1, and FIG. 2D shows the temperature change rate of the sample length. It is a thing. Figure 3 is a graph showing a C2-4 generation behavior of gas and CH ₄ generated when heated heating coal. FIG. 4 is a graph showing the relationship between the amount of C2-4 gas generated when coal is heated and heated and the coke shrinkage rate. FIG. 5 is an IR absorption spectrum of a hydrocarbon gas (sample in the figure) and CH _{4 standard gas (CH 4) generated when coal is heated to a high temperature.} FIG. 6 is a graph showing the relationship between the amount of C2-4 gas generated when the coal is heated and heated and the temperature of the heating and heating. _{FIG. 7 is a graph showing the relationship between the temperature T 1 at} which the amount of C2-4 gas generated is maximized by heating the coal by raising the temperature and the solidification temperature of the coal. Figure 8 is a graph showing the relationship between a C2-4 gas generation rate V ₁ and the coke shrinkage at temperature T _1. Figure 9 is a graph showing the relationship between a C2-4 gas accumulated generation amount V ₂ and coke shrinkage that occurred up to temperature T ₂ from the temperature T _1. Figure 10 is a graph showing the relationship between the temperatures _{T 1} the temperature _T 2 = 1000 ° C. from (= T) C2-4 gas accumulated generation amount generated by _{V 2} and coke shrinkage. FIG. 11 is an overall schematic explanatory view of a gas monitoring device used for measuring C2-4 gas. FIG. 12 shows the effect of the temperature rising rate when measuring the amount of hydrocarbon gas (HC gas) generated using the gas monitoring device of FIG. 11, and FIG. 12A shows the effect of the temperature rising rate of C2-4 gas. It is a graph which compares the generated amount, and (b) is the graph which compares the generated amount _{of CH 4.} FIG. 13 is a graph showing the relationship between the volatile content of coal and the coke shrinkage rate. FIG. 14 is a graph showing the relationship between the amount of hydrocarbon gas generated when coal is heated and heated and the coke shrinkage rate.

Hereinafter, the present invention will be described in detail.
First, the coke shrinkage rate, which is the subject of the present invention, is measured by the method described in Patent Document 3, and coal is placed in a container and heated to a temperature T equal to or higher than the coal solidification temperature, and then re-solidified. It is represented by a value obtained by dividing the volume difference or length difference of the contents between the solidification temperature and the temperature T by the volume or length at the resolidification temperature. Specifically, the coke shrinkage rate can be measured as follows using the device (high temperature dilatometer) shown in FIG.

This device can raise the temperature to a temperature (1300 ° C) higher than that of a normal dilatometer for testing the expandability of coal, and has a double structure of an internal thin tube 2 and an external thin tube 3 as a container for coal. The sample tube 4 having the above is used. That is, the device (high temperature displacement meter) used here heats the sample tube 4, the piston 6 placed on the coal 1 charged in the sample tube 4, and the coal in the sample tube 4 at a predetermined temperature rise rate. It is provided with an electric furnace 8 having a heater 7 capable of capable of using a heater 7 and a laser displacement meter 9 for measuring the vertical displacement of the piston [FIG. 1 (a)]. Of these, the internal capillary tube 2 has a plurality of ventilation holes 5 on its surface [FIGS. 1 (b) and 1 (a)] so that the gas generated by coal can escape to the outside of the internal capillary tube 2. It has become. This is because if coal generates pyrolysis gas during softening and melting and expands significantly, molten coal and tar will enter the gap between the piston 6 and the internal capillary tube 2, and the movement of the piston will be restricted after resolidification. By providing the vent hole 5 in the internal thin tube 2, the gas at the time of softening and melting is discharged to suppress the expansion, and the shrinkage after resolidification can be measured. Further, the upper end of the external pipe 3 is covered with a lid 10 and acts as a guide for preventing the piston 6 from being displaced [FIG. 1 (b)].

When the coal 1 is charged into the sample tube 4, a thin sheet 11 such as paper through which the pyrolysis gas can pass is inserted along the inside of the internal thin tube 2 to charge the coal crushed to a predetermined particle size. The coal is put in, the coal is prevented from spilling from the ventilation hole 5 of the internal thin tube 2, and the coal in the sample tube 4 is heated at a predetermined temperature rising rate [FIG. 1 (b)]. Then, while measuring the vertical displacement of the piston with respect to the heating temperature, the coke shrinkage ratio R (-) is calculated from the piston height h at the resolidification temperature and the piston height h'at the temperature T according to the following equation (1). ) Can be obtained. At this time, in consideration of the thermal expansion of the piston 6 due to the temperature rise, the effect of the piston expansion is obtained in advance as a function of the temperature based on the actual value in the blank, and the coke shrinkage rate according to the equation (1). The correction may be added at the time of calculation of.
R = (h-h') / h ... (1)

Here, in specifying the resolidification temperature when coal is heated by this measurement, as shown in Patent Document 3, the behavior of the piston displacement changes significantly as the temperature rises, and the piston height suddenly increases. The decreasing temperature can be the solidification temperature. Specifically, using the above device, the length (or volume, the same applies hereinafter) of the coal 1 being heated is continuously measured based on the position of the piston 6, and per unit temperature change during the temperature increase. When the change in coal length (hereinafter referred to as sample length) is calculated and used as the rate of change in length and the relationship with temperature is observed, the rate of change in length decreases in the temperature range of about 400 to 550 ° C and then suddenly increases. Since a temperature that increases can be found, this temperature can be used as the solidification temperature of coal.

FIG. 2A shows the relationship between the sample length and the temperature when the coke shrinkage rate of a certain brand of coal is measured. At about 400 ° C., the coal softens and melts, and then the piston sinks. It can be seen that the sample length is decreasing. Further, FIG. 2B is an enlargement of the sample length change due to the temperature rise in the vicinity of 470 ° C. The behavior of the sample length fluctuation changes significantly at the boundary of 470 ° C, and the length decreases sharply. Therefore, it is identified as the resolidification temperature of this coal.
Note that FIG. 2C shows the relative length calculated at each temperature with the sample length at the solidification temperature as 1, and FIG. 2D shows the temperature change rate of the sample length. It is a thing. As shown in FIG. 2 (d), the shrinkage coefficient (-/ K), which is the change in relative length per unit temperature change, is the largest immediately after resolidification. In addition, there is a maximum value of the shrinkage coefficient at about 700 ° C., which is considered to be associated with hydrogen desorption.

On the other hand, the temperature T can be arbitrarily set as long as the temperature is equal to or higher than the coal solidification temperature. For example, in the coal and coke-industrial analysis method specified in JIS M8812: 2004, the ash content is heated to 815 ° C., and in the volatile content determination method, the temperature is 900 ° C., which is preferable in consideration of these factors. Is preferably 800 ° C. or higher and 1300 ° C. or lower. More preferably, since the obtained coke shrinkage rate is used for estimating the particle size and strength of coke, it is preferable to set it as the carbonization temperature when coke is obtained from coal, specifically, 900 ° C. or higher and 1100. It should be below ° C.

In the present invention, the above-mentioned coke shrinkage rate is obtained (estimated) without using the apparatus shown in FIG.
The present inventors have stated that the shrinkage phenomenon of coke (or semi-coke) occurs when coal is softened and melted and resolidified, and moreover, a part of coke (or semi-coke) is partially resolidified by heating. Since it is also related to desorption as gas, we thought that the phenomenon of shrinkage could be grasped by investigating the amount of gas generated when coal was heated and its behavior. Therefore, first, among the gases generated when coal is heated in an inert atmosphere, the coke shrinkage rate is determined based on the amount of hydrocarbon gas (HC gas) generated, which is considered to be directly related to the decomposition of the coal structure. I tried to estimate. However, no significant correlation was found between them.

In examining the reason for this, a hydrocarbon-based gas having 1 carbon atom (CH ₄ ) and a hydrocarbon-based gas having 2 to 4 carbon atoms (hereinafter referred to as C2-4) generated when coal is heated to 1000 ° C. As a result of investigating the generation behavior of each of them (called gas), the results shown in FIG. 3 were obtained. That is, compared to the peak in which the amount of C2-4 gas generated is maximum, the peak in which the _{amount of CH 4} is generated is on the high temperature side, and the amount of gas generated is overwhelmingly _{larger in CH 4.} Regarding this point, since _{the generation of CH 4} includes secondary decomposition and tertiary decomposition of hydrocarbons, _{it is presumed that the amount of CH 4} generated does not directly reflect the structure of coal.

By the way, a coal sample (about 50 mg) installed in a quartz core tube (about 80 ml) in advance is heated to 1000 ° C at 6 ° C / min under nitrogen gas flow, and the generated gas is analyzed by infrared spectroscopy. Nitrogen gas was continuously introduced into the device as a carrier (100 ml / min), and a filter for removing the tar component was inserted before the gas was introduced into the analyzer, and the hydrocarbon component measured by this was investigated. However, most of them have 1 to 4 carbon atoms, and are typically CH ₄ , C ₂ H ₆ , C ₂ H ₄ , C ₃ H ₈ , C ₃ H ₆ , and C ₄ H ₁₀ .

Therefore, we confirmed the relationship between the total amount of C2-4 gas generated when coals of different brands (coals A to F) were heated from room temperature to 1000 ° C. and the coke shrinkage rate. As shown, although there is a tentative correlation between them (coefficient of determination R ² = 0.7812), the results are not so different from the conventionally known correlation between the volatile matter (VM) of each coal and the coke shrinkage rate. there were. Incidentally, the graph shown in FIG. 13 shows the relationship between the volatile matter (VM) of coals A to F and the coke shrinkage rate.

By the way, in investigating the correlation as shown in FIG. 4, the IR absorption spectrum of the HC gas generated when the coal is heated to 1000 ° C. is as shown in FIG. 5 (Sample in the figure), and CH. ₄ Compared with the IR absorption spectrum of the standard gas, in the absorption wave number range of the infrared absorption wave number 2820 cm ^{-1 to} 2880 cm ^-1 (a part of the absorption range caused by the expansion and contraction vibration of CH), the absorption peak derived from _{CH 4 (} Infrared absorption wave number 2880cm ^{-1 to} 3180cm ^-1 ) is hardly included. Therefore, the area value of the absorbance of the HC gas generated by heating coal at the above infrared absorption wave number (2820 cm ^{-1 to} 2880 cm ^-1 ) is obtained, and this absorption intensity is used as the amount of C2-4 gas generated, and coal is used. The amount of C2-4 gas generated was continuously measured while heating at a high temperature, and the relationship between the heating temperature and the amount of C2-4 gas generated was determined. FIG. 6 shows the generation behavior of C2-4 gas of coals A to F thus obtained. Although the range from 300 ° C. to 600 ° C. is enlarged in FIG. 6, the measurement was actually performed while heating the coal from room temperature to 1000 ° C. In addition, for comparison, the area value of the absorbance at an infrared absorption wave number of 2820 cm ^{-1 to} 2997 cm ^-1 _{, including the absorption peak derived from CH 4} , was obtained, and the relationship with the coke shrinkage rate as the amount of hydrocarbon gas generated was determined. What is shown is FIG. This was inferior in correlation as described above.

According to the graph shown in FIG. 6 showing the relationship between the amount of C2-4 gas generated when the coal is heated and heated and the temperature of the heating and heating, the amount of C2-4 gas generated is the maximum. Although the temperature at which it becomes is different depending on the coal type, the generation behavior of C2-4 gas with respect to the heating temperature shows a similar tendency. Therefore, when each coal was measured by heating and heating as described above, _{the relationship between the temperature T 1 at} which the amount of C2-4 gas generated at that time was maximized and the resolidification temperature of each coal was investigated. As shown in FIG. 7, it was found that the correlation was extremely good. As described above, the coal solidification temperature referred to here is determined by the temperature at which the behavior of sample length fluctuation changes when the coke shrinkage rate is measured using a high-temperature dilatometer.

Therefore, based on this finding, for coals A to F, _{C2-4 gas generation amount V 1} and coke shrinkage _{at the temperature T 1} where the C2-4 gas generation amount is maximized by the above-mentioned temperature rise and heating measurement. The relationship with the rate is as shown in Fig. 8 (coefficient of determination R ² = 0.8981), which is compared with the relationship between the total amount of C2-4 gas generated and the coke shrinkage rate shown in Fig. 4 above. , It was found that the correlation was improved. That is, among the gases generated when coal is heated and heated, the amount of C2-4 gas, which is a hydrocarbon-based gas having 2 to 4 carbon atoms, is measured, and the temperature T at which the amount of generation is maximized. _If the C2-4 gas generation amount V _{1 in 1 is obtained (T 1} and V _{1 in} the case of coal F are shown in FIG. 6), it is based on the obtained C2-4 gas generation amount V _1. Therefore, it is possible to estimate the coke shrinkage rate at the temperature T of the coal (however, T ₁ <T). The coke shrinkage rate in FIGS. 4 and 8 was obtained by heating coal by heating it from room temperature to 1000 ° C. using the above-mentioned high-temperature dilatometer.

In the present invention, preferably, in place of C2-4 gas generation amount V ₁ of the at temperatures T ₁ in the temperature elevation heating measurement of coal as described above, from the temperatures T ₁ to a temperature T ₂ of the heating heating It is better to use _{the integrated amount V 2} of C2-4 gas generated in the meantime _{(however, T 1} <T ₂ ≤ T), so that the coke shrinkage rate of the coal at the temperature T is The accuracy of estimation can be improved.

That is, in FIG. 9, among the relationships between the amount of C2-4 gas generated in the coals A to F shown in FIG. 6 and the temperature of the heating and heating, the C2-4 gas of each coal is measured in the heating and heating measurement. Relationship between C2-4 cumulative gas generation amount V _{2 of each coal generated from temperature T 1} to temperature T ₂ = 500 ° C, which is the maximum amount of generation, and coke shrinkage rate, and temperature T ₁ to temperature T ₂ = 600 relationship with C2-4 gas accumulated generation amount V ₂ and coke shrinkage rate of each coal that occurred up ° C., and, likewise C2-4 gas accumulated in the coal that occurred from temperatures T ₁ to a temperature T _{2 =} 700 ° C. and is shown the relationship between the generation amount V ₂ and coke shrinkage, both shown in FIG. 8, the correlation between coke shrinkage than with C2-4 gas generation amount V ₁ of the at temperatures T ₁ sex is improved (T _{2 =} 500 ℃ determining factor in _{^{R 2 = 0.9402, T 2 =}} 600 determined at ° C. coefficient R ² = 0.9558, the coefficient of determination R ² = 0.9795 at T _{2 =} 700 ℃). Most preferably, as shown in FIG. 10, when measuring the coke shrinkage rate using a high temperature coefficient of determination, the temperature T for heating to a temperature T equal to or higher than the resolidification temperature is preferably set to the temperature T ₂ (FIG. 10). In the example, T = T ₂ = 1000 ° C), and the correlation with the coke shrinkage rate is further improved (coefficient of determination R ² = 0.9892).

In the present invention, when estimating the coke shrinkage at a temperature T of the coke produced from the coal, and more specifically, for example, a plurality of coal at temperatures T ₁ by heating the heating measurement as described above C2-4 In addition to obtaining the amount of gas generated V ₁ and comparing them relative to each other to estimate the magnitude of the coke shrinkage rate, the above-mentioned temperatures for a plurality of test coals having a known coke shrinkage rate at the temperature T, respectively. Obtain the C2-4 gas generation amount V ₁ at T ₁ , obtain the relational data by plotting each C2-4 gas generation amount V ₁ and the coke shrinkage rate on a graph, and obtain the relational data, and obtain the coke at the temperature T. For new coal whose shrinkage rate is unknown, the coke shrinkage rate may be estimated.

Among them, correlations Preferably, the coke shrinkage for a plurality of known test coal at a temperature T, as described above, previously, a C2-4 gas generation amount V ₁ and coke shrinkage rate of each test coal It is better to get the formula. Since the correlation equation thus obtained can be repeatedly used for a plurality of coals having an unknown coke shrinkage rate at a temperature T, a coal having an unknown coke shrinkage rate at a temperature T can be used repeatedly. the generation amount of C2-4 gas was measured while elevating the heating, by obtaining the ₁ 'C2-4 gas generation amount V at _1' a temperature T which the generation amount is maximized, it is described in Patent Document 3 It is possible to easily and accurately estimate the coke shrinkage rate for any coal type without using such a device. When obtaining such a correlation equation, C2-4 gas integrated generation amount V _{2 may be used instead of C2-4 gas generation amount V 1} as described above. In that case, by coke shrinkage seek ₂ 'C2-4 gas accumulated generation amount V from ₁ to a temperature T _2' temperature T of unknown coal, it is possible to further enhance the estimation accuracy.

As for the test coal whose coke shrinkage rate at the temperature T is known to be prepared for obtaining such a correlation equation, it is preferable to prepare a plurality of test coals having different production areas and brands and different coke shrinkage rates, preferably. It is good to prepare 5 or more. At that time, since the coke shrinkage rate is generally about 10 to 18%, it is desirable to include those on the upper limit side and the lower limit side of this numerical range.

Further, in the present invention, as a method of measuring the amount of C2-4 gas generated by heating and heating coal, at least the temperature T _{1 at} which the amount of C2-4 gas generated is maximized is obtained by the temperature heating and heating measurement. Anything that can be used is sufficient. For example, C2-4 gas is produced by mass spectrum or gas chromatography while storing the gas generated from the heating start temperature (room temperature) to the heating end temperature (T) in a gas sampling bag or the like. Although it is possible to measure it, preferably, as described above, the IR absorption spectrum while heating the coal while heating the coal so that the _{temperature T 1 at which the generated amount is maximized can be accurately obtained.} Should be able to measure continuously.

That is, preferably, a gas monitoring device used for analysis of coal carbonization reaction (Nishito et al. (2010). Analysis of coal carbonization reaction by gas monitoring and continuous measurement of coke oven generated gas Nippon Steel Technical Report No. 390, 101 -111.) Is used to continuously measure the generated C2-4 gas. FIG. 11 shows an overall schematic view of this gas monitoring device. In this device, a sample (coal) is flowed through a gas purifier 22 and a flow meter 23 while a carrier gas 21 such as nitrogen, which is an inert gas, is flowing. ) 25 is heated in a tubular electric furnace 26, and the generated gas is connected to a computer 30 via a tar trap 27. A Fourier transform infrared spectroscope (FT-IR) 29. It is introduced into the gas measurement cell 28 of the above. With such a gas monitoring device, it is not necessary to use a gas sampling bag or the like, and C2-4 gas generated by heating and heating coal can be continuously measured.

Further, in the present invention, when the C2-4 gas is measured by heating the coal at a predetermined heating rate, it is desirable that the conditions are such that the operating state in the actual coke oven is imitated. .. Generally, the rate of temperature rise of coal in carbonization in a coke oven is around 3 ° C / min, but since the rate of gas generation may change if the rate of temperature rise changes significantly, C2-4 gas is measured. The rate of temperature rise is preferably 3 ° C./min or more and 10 ° C./min or less, and more preferably 3 ° C./min or more and 6 ° C./min or less. The same applies to the case where the coke shrinkage rate is measured using a high temperature dilatometer.

By the way, in FIG. 12, the gas monitoring device shown in FIG. 11 was used to heat the coal at a heating rate of 3 ° C./min and to heat the coal at a heating rate of 6 ° C./min. A comparison of gas generation behavior between cases is shown. FIG. 12A shows the amount of C2-4 gas generated, and FIG. 12B _{shows the amount of CH 4} generated, and there is no change in the amount of gas generated or the pattern of generation. Further, it was confirmed that even when the temperature rising rate was at least 10 ° C./min, there was no particular change in the amount of gas generated and the pattern of generation, and there was no effect on the estimation of the coke shrinkage rate. Since the heating rate of 3 ° C./min is 1/2 that of 6 ° C./min and the amount generated per hour is halved, the horizontal axis of the graph in FIG. 12 is arranged by the heating temperature. In each case, the amount of gas generated is doubled.

Further, in the present invention, when the C2-4 gas is measured by heating the coal by raising the temperature, the heating may be started from room temperature, but in general, the generation of hydrocarbon gas (HC gas) is about 250 ° C. In consideration of work efficiency, at least 200 ° C. may be set as the heating start temperature. On the other hand, as the heating end temperature, heating may be performed up to a temperature T (preferably a carbonization temperature), but the temperature T ₁ at which the amount of C2-4 gas generated is maximized or the temperature T ₂ is used. But it doesn't matter.

Further, the coke shrinkage rate of each simple coal used for compounding is obtained by the method of the present invention, and the coke shrinkage rate of each obtained simple coal is weighted averaged according to the compounding ratio to obtain the coke shrinkage rate of the compounded coal. Can also be estimated. Therefore, based on the coke shrinkage rate of the blended coal thus obtained, for example, the particle size of coke can be estimated by the method described in Patent Document 3 described above, or the volume fracture or the coke strength can be estimated. If you use it, you will be able to obtain more accurate results.

Hereinafter, the present invention will be described based on examples, but the present invention is not limited to these contents.

(Example 1)
Coals A to F having properties according to the industrial analysis and elemental analysis shown in Table 1 were prepared. Here, the ash content (dry.%) In the table represents the mass fraction of the amount of ash remaining when heated ash under the conditions specified in the industrial analysis method of JIS M8812, and the volatile content (dry.%). ) Is obtained by the volatile matter quantification method also specified in the industrial analysis method of JIS M 8812.

For these coals A to F, the coke shrinkage rate at a temperature T = 1000 ° C. was determined as follows using the apparatus (high temperature dilatometer) shown in FIG. That is, the internal capillary tube 2 of the device used for the measurement is composed of a cylindrical container made of SUS having an inner diameter of 8 mm and an outer diameter of 14.5 mm, and holes 5 having a diameter of 1 mm are totaled at eight locations in the circumferential direction and at intervals of 2 mm in the height direction. 368 pieces are provided. The outer thin tube 3 is arranged concentrically with the inner thin tube 2, and the material of the outer thin tube 3 is SUS, the inner diameter is 16 mm, and the outer diameter is 24 mm. The piston 6 can be charged into the internal capillary tube from above, and the lower end portion of the piston 6 has a diameter of 7.5 mm and is arranged so as to be in contact with the upper end portion of the coal 1 charged in the internal capillary tube 2. .. Further, the vertical position of the piston 6 can be measured by the laser displacement meter 9, and further, the coal 1 charged into the internal thin tube 2 by an electric furnace provided with a heater 7 on the outside of the external thin tube 3. The temperature can be heated up to 1300 ° C.

Then, a paper (thin sheet) 11 having a thickness of about 50 μm is charged along the inner circumference of the internal thin tube 2, and 1.25 g of crushed coal of -3 mm (3 mm or less) is charged therein, and the piston 6 is charged. The temperature was raised to 1000 ° C. by the heater 7 at a heating rate of 3 ° C./min. At that time, the length (sample length) of the coal 1 being heated was continuously measured based on the position of the piston 6. Further, during the temperature rise, the change in the sample length per unit temperature change was calculated and used as the length change rate, and when the relationship with the temperature was observed, the length change rate was found in the temperature range of 400 to 550 ° C. A temperature that decreased and then rapidly increased was found, and this temperature was defined as the resolidification temperature of the coal. Such measurements were carried out for each of the coals A to F, and the coke shrinkage rate at 1000 ° C. was determined based on the above formula (1). The results are shown in Table 1.

Further, the amount of C2-4 gas generated when each of these coals A to F is heated from room temperature to a temperature T = 1000 ° C. is measured as follows using the gas monitoring device shown in FIG. did.
A 50 mg coal sample 25 placed on a quartz boat was placed in a quartz core tube 24 having an internal volume of about 40 ml, and heated from room temperature to 1000 ° C. at a heating rate of 6 ° C./min by a tubular electric furnace 26. At that time, nitrogen was flowed as a carrier gas 21 at a flow rate of 100 ml / min (gas pressure: 0.1 MPa) through the gas refiner 22 and the flow meter 23, and the coal sample 25 in the core tube 24 was in a constant nitrogen stream. It was made to be heated.

The HC gas generated from the coal sample 25 is continuously measured in the gas measurement cell 28 of FT-IR having an optical path length of 2 cm (measurement interval is 1 second), and at that time, the infrared absorption wavenumber is 2820 cm ^{-1 to} 2880 cm ^-1. The absorption wavenumber range of the above was selected so that the absorbance (area value) in the absorption wavenumber range was continuously recorded on the computer 30. Then, since this area value indicates the absorption intensity in the absorption wave frequency range, this is used as the amount of C2-4 gas generated, and the coal is heated and heated to continuously measure the amount of this C2-4 gas generated. Then, the relationship between the heating temperature of each coal and the amount of C2-4 gas generated was calculated. The results are as shown in FIG. 6 above.

Then, the coal to F, from 6 obtained above, temperatures T ₁ generation amount of each C2-4 gas is _maximized, C2-4 gas generation amount V ₁ of the at that temperature T _{1 and,} C2-4 gas integrated amount generated from temperature T ₁ to temperature T ₂ (= 1000 ° C) V ₂ is obtained, and for these, C2-4 gas at temperature T ₁ where the amount of C2-4 gas generated is maximized. The relationship between the generated amount V ₁ and the coke shrinkage rate is as shown in Fig. 8 above, and the C2-4 gas integrated generated amount V from temperature T _{1 to temperature T 2 (= 1000 ° C). The relationship between 2} and the coke shrinkage rate was as shown in FIG. All of these have a good correlation, and when the coke shrinkage rate is x (horizontal axis) and the amount of gas generated is y (vertical axis), FIG. 8 is represented by the correlation equation of the following equation (2). This can be done, and FIG. 10 can be represented by the correlation equation of the following equation (3).
y = 70.8x + 74.4 ... (2)
y = 0.101x-0.536 ... (3)

Therefore, it occurred when coal G having the properties shown in Table 2 below and whose coke shrinkage at 1000 ° C. was unknown was heated from room temperature to 1000 ° C. at a heating rate of 6 ° C./min in the same manner as above. C2-4 by measuring the amount of gas generated, the temperature T _'1, the temperature T' of the generation amount is maximized C2-4 gas generation amount V at _{1 '1 and} the temperature T' temperature T _{1 2 (=} 1000 ° C.) was examined C2-4 gas accumulated generation amount V _'2 up, were as shown in Table 2. Then, when the coke shrinkage rate was obtained using the correlation equation (2) according to FIG. 8 obtained above, the estimated value was 14.9%. Similarly, when the coke shrinkage rate was determined using the correlation equation (3) according to FIG. 10, the estimated value was 14.6%.

When the coke shrinkage of the coal G was actually measured using the above-mentioned device (high temperature dilatometer) for measuring the coke shrinkage of the coals A to F, it was 14.6%. That is, in either case of using the correlation equations (2) and (3) obtained above, the coke shrinkage rate close to the measured value can be estimated, and especially when the correlation equation (3) is used. Was found to be extremely accurate.

As described above, among the gas generated upon heating temperature of the coal, C2-4 generation of C2-4 gas is hydrocarbon gas having 2 to 4 carbon atoms is at temperatures T ₁ is maximized Since the amount of gas generated V ₁ has a correlation with the coke shrinkage rate at the temperature T of the coal, the C2-4 amount of gas generated V ₁ and the coke shrinkage rate can be calculated without calculating the above correlation formula. As long as it is plotted on a graph, the coke shrinkage rate can be estimated for a new coal whose coke shrinkage rate at temperature T is unknown. Alternatively, for example, a plurality of coal, by measuring the C2-4 gas generation amount V ₁ of the at each temperature T _1, it is also possible to estimate the magnitude of their relatively compared to coke shrinkage , Not only used for predicting the particle size and strength of coke, but also various usage forms are expected in the production of coke for blast furnaces.

1: Coal 2: Internal thin tube 3: External thin tube 4: Sample tube 5: Vent, 6: Piston, 7: Heater, 8: Electric furnace, 9: Laser displacement meter, 10: Lid, 11: Thin Sheet, 21: Carrier gas, 22: Gas purifier, 23: Flow meter, 24: Core tube, 25: Sample (coal), 26: Tubular electric furnace, 27: Tar trap, 28: Gas measurement cell, 29: Fourier transform infrared spectroscope (FT-IR), 30: Computer.

Claims (6)

A value obtained by putting coal in a container and heating it to a temperature T equal to or higher than the resolidification temperature of coal, and dividing the volume difference or length difference of the contents between the resolidification temperature and the temperature T by the volume or length at the resolidification temperature. It is a method of estimating the coke shrinkage rate at the temperature T of the coke produced from the coal, which is represented by.
Of the gases generated when coal is heated at a predetermined temperature rise rate for a plurality of coals, C2-4 gas, which is a hydrocarbon-based gas having 2 to 4 carbon atoms, is measured, and this temperature rise heating measurement is performed. seeking respectively C2-4 gas generation amount V ₁ of the at temperatures T ₁ where the amount generated is maximized in (but, T 1 is a _<T), relatively C2-4 gas generation amount V ₁ obtained A method for estimating the coke shrinkage rate, which comprises estimating the magnitude of the coke shrinkage rate at the temperature T of each coal by comparison. A value obtained by putting coal in a container and heating it to a temperature T equal to or higher than the resolidification temperature of coal, and dividing the volume difference or length difference of the contents between the resolidification temperature and the temperature T by the volume or length at the resolidification temperature. It is a method of estimating the coke shrinkage rate at the temperature T of the coke produced from the coal, which is represented by.
C2, which is a hydrocarbon-based gas having 2 to 4 carbon atoms, among the gases generated when the coal is heated at a predetermined temperature rise rate for a plurality of test coals having a known coke shrinkage rate at a temperature T in advance. -4 Gas is measured, and C2-4 gas generated amount V _{1 at the temperature T 1} at which the generated amount is maximized in this heating and heating measurement is obtained (however, T ₁ <T), and each test is performed. advance to obtain the correlation equation between C2-4 gas generation rate V ₁ and the coke shrinkage use coal,
For coal coke shrinkage unknown at the temperature T, the generation amount of C2-4 gas in its Atsushi Nobori heating measurement based on ₁ 'C2-4 gas generation amount V at _1' a temperature T that maximizes (where T 'is a _{1 <T),} the method of estimating the coke shrinkage and estimates coke shrinkage from the correlation equation. Instead of the C2-4 gas generation amount V ₁ , it is based on the C2-4 gas integrated generation amount V ₂ from the temperature T _{1 to the temperature T 2} when the C2-4 gas generation amount is measured (however, however). The _{method for estimating the coke shrinkage rate according to claim 1 or 2, wherein T 1} <T ₂ ≤ T) and the coke shrinkage rate at the temperature T of the coal is estimated. The method for estimating the coke shrinkage rate according to any one of claims 1 to 3, wherein the temperature T is a carbonization temperature when coke is obtained from coal. The method for estimating the coke shrinkage rate according to claim 3 or 4, wherein the temperature T _{2 is the temperature T.} The coke shrinkage rate is measured by using a sample tube having a double structure of an internal thin tube and an external thin tube provided with a plurality of vents as a container for containing coal, and the coal is placed in the sample tube. The vertical displacement of the piston with respect to the heating temperature is measured while the coal is loaded and heated at a predetermined temperature rise rate, based on the piston height at the coal solidification temperature and the piston height at the temperature T. The method for estimating the coke shrinkage rate according to any one of claims 1 to 5, which is calculated.

Images