JP2010190761A - Method for evaluating softening and melting characteristics of coal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating softening and melting characteristics of coal capable of more precisely evaluating the softening and melting characteristics of coal by measuring the softening and melting characteristics of coal in a condition that simulates surrounding environment of coal softened and melted in a coke oven. <P>SOLUTION: The method for evaluating the softening and melting characteristics of coal includes the steps of arranging a material 2 with a through-hole penetrating the upper and the lower surface of a coal sample 1, which is filled with a predetermined amount of coal in a container, on the sample 1 to maintain the coal sample 1 and the material 2 with the through-hole penetrating the upper and the lower surface at a constant volume, therewith, measuring a penetration distance of molten coal penetrated in the through-hole when heating the coal sample 1 at a predetermined heating rate, and evaluating the softening and melting of coal using the penetration distance measured. Alternatively, the method includes the steps of maintaining the coal sample 1 and the material 2 with the through-hole penetrating the upper and the lower surface at a constant volume, therewith, heating the coal sample 1 at a predetermined heating rate, measuring the pressure of coal transmitted through the material 2 with the through-hole penetrating the upper and the lower surface, and evaluating the softening and melting characteristics of coal using the penetration distance measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a test method for evaluating softening and melting characteristics during coal dry distillation, which is one of quality evaluation methods for coal for coke production.

  For coal for coke production, softening and melting properties are a very important property. In the blast furnace coke, in order to maintain the air permeability in the blast furnace, it is required to produce a robust coke. Coal is softened and melted by dry distillation and adheres to each other to form coke. Therefore, it can be said that the difference in the softening and melting characteristics of coal has a great influence on the coke strength.

  As a method for measuring the softening and melting characteristics of coal, there is a coal fluidity test method by the Giesera plastometer method defined in JIS M8801. In the Giesera plastometer method, coal pulverized to 425 μm or less is put in a predetermined crucible, heated at a specified temperature rise rate, measured for the rotation speed of a stirring rod with a specified torque applied, and divided into scales every minute. Is a method for expressing the softening and melting characteristics of the sample.

  In contrast to the Giesera plastometer method, which measures the rotational speed of the stirring rod with a constant torque, a method for measuring the torque with a constant rotation method has also been devised. For example, Patent Document 1 describes a method of measuring torque while rotating a rotor at a constant rotational speed.

  In addition, there is a viscosity measurement method using a dynamic viscoelasticity measuring device for the purpose of measuring a physically meaningful viscosity as a softening and melting characteristic (see, for example, Patent Document 2). The dynamic viscoelasticity measurement is to measure a response when a force is periodically applied to the viscoelastic body. The method described in Patent Document 2 is characterized in that the viscosity of the softened molten coal is evaluated by the complex viscosity in the parameters obtained by the measurement, and the viscosity of the softened molten coal at an arbitrary shear rate can be measured. .

  Furthermore, as an example of the softening and melting characteristics of coal, an example in which activated carbon or glass beads was used and the coal softening melt adhesion to them was measured was reported. In this method, a small amount of coal sample is heated while being sandwiched between activated carbon and glass beads from above and below, cooled after softening and melting, and the adhesion between coal, activated carbon and glass beads is observed from the appearance.

  In addition to fluidity, expansibility is also regarded as important as a softening and melting characteristic of coal. A typical method is a dilatometer method defined in JIS M8801. Furthermore, in order to simulate the behavior of coal softening and melting in a coke oven, a coal expansibility test method that improves the permeation behavior of gas generated during softening and melting of coal is also known (see, for example, Patent Document 3). This is because the permeable material is placed between the coal bed and the piston, or between the coal bed and the piston and at the bottom of the coal bed, and the permeation path of gas and liquid substance is increased. This is a method close to the expansion behavior.

JP-A-6-347392 JP 2000-304673 A Japanese Patent No. 2855728

Morotomi et al .: “Journal of Fuel Association”, Vol. 53, 1974, p. 779 Miyazu et al .: “Nippon Steel Pipe Technical Report”, vol. 67, 1979, p. 125

  In order to evaluate the softening and melting behavior of coal in a coke oven, it is necessary to measure the softening and melting characteristics of coal in a state simulating the environment around the coal softened and melted in the coke oven. However, the conventional method has the following problems.

  The Giesera plastometer method is problematic in that it does not take into account any restraint or infiltration conditions for measurement in a state where coal is filled in a container. In addition, the Giesera Plastometer is not suitable for measuring coal with high fluidity. Coal softens, foams and expands when softened and melted, but when measuring coal exhibiting high fluidity, a phenomenon (Weissenberg effect) in which the inner wall of the container becomes hollow is observed (for example, Non-Patent Document 1). reference.). As a result, since the stirring rod is idle, it is difficult to correctly measure the fluidity.

  Similarly, the method of measuring the torque by the constant rotation method is deficient in that the constraint condition and the penetration condition are not taken into consideration. In addition, because of the measurement under a constant shear rate, it is impossible to correctly compare and evaluate the softening and melting characteristics of coal as described above.

  The dynamic viscoelasticity measuring apparatus is an apparatus that targets viscosity as a softening and melting characteristic and can measure the viscosity under an arbitrary shear rate. Therefore, if the shear rate is the value of the behavior in the coke oven, the viscosity of the softened molten coal in the coke oven can be measured. However, it is necessary to set by measuring or estimating the shear rate of each brand, which is complicated.

  The method of measuring the adhesion to coal using activated carbon or glass beads as the softening and melting characteristics of coal is trying to reproduce the infiltration conditions for the presence of the coal layer, but does not simulate the coke layer and coarse defects There is a problem in terms. Moreover, the point which is not a measurement under restraint is also insufficient.

  In the coal expansibility test method using the permeable material described in Patent Document 3, the movement of gas and liquid substance generated from coal is considered, but the movement of softened and melted coal itself is considered. There is not enough in that. This is considered to be because the permeability of the permeable material used in Patent Document 3 is not sufficiently high to move the softened molten coal. New conditions must be taken into account in order for softened molten coal to penetrate.

  As described above, in the conventional technology, the softening and melting characteristics of coal cannot be measured in a state simulating the environment around the coal softened and melted in the coke oven.

  Accordingly, the object of the present invention is to solve such problems of the prior art, measure the softening and melting characteristics of the coal in a state of simulating the environment around the softened and melted coal in the coke oven, and soften and melt the coal. An object of the present invention is to provide a method for evaluating the softening and melting characteristics of coal, which can more accurately evaluate the characteristics.

  In order to evaluate the softening and melting behavior of coal in a coke oven, it is necessary to measure the softening and melting characteristics of coal in a state simulating the environment around the coal softened and melted in the coke oven. The present inventors have verified a conventional measurement method and found that it is important to newly appropriately control two conditions of constraint conditions and penetration conditions. The basis for controlling the above two conditions will be described below.

  In the coke oven, the coal at the time of softening and melting exhibits softening and melting properties while being constrained by adjacent layers. Since the thermal conductivity of coal is small, the coal is not uniformly heated in the coke oven, and the state differs from the coke layer, the softened molten layer, and the coal layer from the furnace wall side that is the heating surface. Since the coke oven itself expands somewhat during dry distillation but hardly deforms, the softened and melted coal is constrained by the adjacent coke layer and coal layer. Therefore, it is important for the evaluation of the softening and melting characteristics to perform measurement under conditions simulating the constraints of the adjacent coke layer and coal layer.

  Moreover, it is considered that the softened and melted coal moves to a defect structure existing around. There are various defect structures around the softened and melted layer, such as voids between coal particles in the coal layer, voids between particles of the softened molten coal, rough air holes generated by volatilization of the pyrolysis gas, and cracks generated in the adjacent coke layer. In particular, the crack generated in the coke layer is considered to have a width of several hundred microns to several millimeters, and is larger than the voids and pores between coal particles having a size of about several tens to several hundreds of microns. For this reason, it is considered that not only pyrolytic gas and liquid substances, which are by-products generated from coal, but also softened and melted coal itself moves to such coarse defects generated in the coke layer. Therefore, in order to evaluate the softening and melting characteristics of coal, it is necessary to measure by simulating the penetration conditions of surrounding defect structures, particularly coarse defects.

  Furthermore, in order to compare and evaluate the coal softening and melting characteristics in the coke oven for various coal brands, the coal is softened and melted in the coke oven and moved to the surrounding defect structure or deformed. It is necessary to measure under shear rate. In this case, since the shear rate is expected to be different for each brand, it is required to set the measurement conditions such that the deformation and movement behavior of each brand during softening and melting is equal to the behavior in the coke oven. Therefore, when evaluating the coal softening and melting characteristics based on the coal softening and melting behavior in the coke oven, it is necessary to reproduce the shear rate in the coke oven, not under a constant shear rate. Must be controlled appropriately for each brand of coal.

The present invention has been made based on such findings, and the features thereof are as follows.
(1) A predetermined amount of coal is filled into a container to obtain a coal sample, a material having through holes on the upper and lower surfaces is placed on the coal sample, and the material having the through holes on the upper and lower surfaces is fixed. When heating the coal sample at a predetermined heating rate while maintaining the volume, the penetration distance of the molten coal that has penetrated into the through-holes is measured, and the softening and melting characteristics of the coal are evaluated using the measured values. A characteristic evaluation method for softening and melting characteristics of coal.
(2) Filling a container with a predetermined amount of coal to make a coal sample, placing a material having through holes on the upper and lower surfaces on the coal sample, and fixing the coal sample and the material having through holes on the upper and lower surfaces While heating the coal sample at a predetermined heating rate while maintaining the volume, the pressure of the coal transmitted through the material having through holes on the upper and lower surfaces is measured, and the measured value is used to measure the coal An evaluation method for softening and melting characteristics of coal, characterized by evaluating softening and melting characteristics.
(3) Filling a container with a predetermined amount of coal to form a coal sample, placing a material having through holes on the upper and lower surfaces on the coal sample, and applying a constant load to the material having the through holes on the upper and lower surfaces. Meanwhile, when the coal sample is heated at a predetermined heating rate, the penetration distance of the molten coal that has penetrated into the through hole is measured, and the softening and melting characteristics of the coal are evaluated using the measured value. Evaluation method for softening and melting characteristics of coal.
(4) Filling a container with a predetermined amount of coal to form a coal sample, placing a material having through holes on the upper and lower surfaces on the coal sample, and applying a constant load to the material having the through holes on the upper and lower surfaces. Meanwhile, when the coal sample is heated at a predetermined heating rate, the expansion coefficient of the coal is measured, and the softening and melting property of the coal is evaluated using the measured value. Evaluation methods.

  According to the present invention, the defect structure existing around the coal softening and melting layer in the coke oven, particularly the coke layer adjacent to the softening and melting layer, which is considered to have a great influence on the coal softening and melting characteristics in the coke oven. Coal softening and melting characteristics can be evaluated while simulating the effect of existing coarse defects and appropriately reproducing the restraint conditions around the softening melt in the coke oven. Further, the penetration distance of coal softened melt into the defect structure, the expansion coefficient during penetration, and the pressure during penetration can be measured at the shear rate when the coal is softened, melted, moved and deformed in the coke oven.

  This makes it possible to accurately evaluate the softening and melting behavior of coal in a coke oven, and can be used to develop high-strength coke.

It is the schematic which shows an example of the apparatus which measures a softening-melting characteristic, keeping the coal sample used by this invention, and the material which has a through-hole in an upper and lower surface at a fixed volume. It is the schematic which shows an example of the apparatus which measures a softening-melting characteristic, applying a fixed load to the coal sample used by this invention, and the material which has a through-hole in an upper and lower surface. It is the schematic which shows an example of what has a circular through-hole among the materials which have a through-hole in the upper and lower surfaces used by this invention. It is the schematic which shows an example of a spherical particle packing layer among the materials which have a through-hole in the upper and lower surfaces used by this invention. It is the schematic which shows an example of a cylindrical packing layer among the materials which have a through-hole in the upper and lower surfaces used by this invention. 4 is a graph showing the measurement results of the penetration distance of the coal softened melt measured in Example 1. FIG. It is a graph which shows the coke strength measurement result of two types of combination charcoal measured in Example 1. It is a graph which shows the measurement result of the penetration distance of the coal softening melt measured in Example 2.

  1 and 2 show an example of an apparatus used in the present invention. FIG. 1 shows an apparatus for heating a coal sample while maintaining a constant volume of the coal sample and the material having through holes on the upper and lower surfaces, and FIG. 2 shows a case where a constant load is applied to the coal sample and the material having the through holes on the upper and lower surfaces. This is an apparatus for heating a coal sample. The lower part of the container 3 is filled with coal to form a coal sample 1, and the material 2 having through holes on the upper and lower surfaces is disposed on the coal sample 1. The coal sample 1 is heated to the softening and melting temperature range or more, the coal is infiltrated into the material 2 having through holes on the upper and lower surfaces, and the infiltration distance is measured. Heating is performed in an inert gas atmosphere.

  When heating the coal sample 1 while maintaining a constant volume of the coal sample 1 and the material 2 having through holes on the upper and lower surfaces, it is possible to measure the pressure during coal penetration through the material 2 having the through holes on the upper and lower surfaces. It is. As shown in FIG. 1, a pressure detection rod 4 is arranged on the upper surface of a material 2 having through holes on the upper and lower surfaces, a load cell 6 is brought into contact with the upper end of the pressure detection rod 4, and the pressure is measured. In order to maintain a constant volume, the load cell 6 is fixed so as not to move up and down. Before heating, the coal filled in the container 3 is brought into close contact with each other so that no gap is formed between the material 2 having a through hole on the upper and lower surfaces, the pressure detection rod 4 and the load cell 6. When the material 2 having through holes on the upper and lower surfaces is a particle packed layer, the pressure detection rod 4 may be buried in the particle packed layer. It is necessary to take measures to sandwich the board.

  When a constant load is applied to the coal sample 1 and the material 2 having through holes on the upper and lower surfaces and the coal sample is heated, the coal sample 1 shows expansion, and the material 2 having the through holes on the upper and lower surfaces moves in the vertical direction. . Therefore, it is possible to measure the expansion rate at the time of coal penetration through the material 2 having through holes on the upper and lower surfaces. As shown in FIG. 2, an expansion coefficient detection rod 13 is arranged on the upper surface of the material 2 having through holes on the upper and lower surfaces, a weight 14 for applying a load is placed on the upper end of the expansion coefficient detection rod 13, and a displacement meter 15 is placed thereon. And the expansion coefficient shall be measured. The displacement meter 15 may be one that can measure the expansion range (-100% to 300%) of the coal expansion rate. Since it is necessary to maintain the inside of the heating system in an inert gas atmosphere, a non-contact type displacement meter is suitable, and it is desirable to use an optical displacement meter. In the case where the material 2 having through holes on the upper and lower surfaces is a particle packed layer, the expansion coefficient detecting rod 13 may be buried in the particle packed layer, and therefore the material 2 having the through holes on the upper and lower surfaces and the expansion coefficient detecting rod 13. It is necessary to take measures to put a board between them.

  It is desirable to use a heating means that can heat at a predetermined rate of temperature while measuring the temperature of the coal sample. Specifically, it is an external heating type such as an electric furnace or a high frequency induction furnace, or an internal heating type such as a microwave. In the case of adopting the internal heating method, it is necessary to devise a method for making the temperature inside the coal sample uniform, for example, taking measures to improve the heat insulating property of the container.

  The heating rate needs to match the heating rate of coal in the coke oven for the purpose of simulating coal softening and melting behavior in the coke oven. Considering the heating rate of coal in the coke oven, it is desirable to set it at about 3 ° C./min. However, in the case of coal with low fluidity such as non-slightly caking coal, the permeation distance is small and the detection sensitivity may be reduced at 3 ° C./min. Since it is known that coal is improved in fluidity by Giesera plastometer by rapid heating, in the case of low-flowing coal, for example, coal with an infiltration distance of 1 mm or less, the heating rate is 10 to 1000 ° C / The detection sensitivity may be improved by measuring in min.

  About the temperature range which heats, since evaluation of a coal softening melting characteristic is an object, it should just be able to heat to a coal softening melting temperature range. In consideration of the softening and melting temperature range of coal exhibiting softening and melting, heating may be performed at a predetermined heating rate in the range of 0 ° C. (room temperature) to 550 ° C.

  The material having through holes on the upper and lower surfaces is preferably one that can measure or calculate the transmission coefficient in advance. Examples of the material include an integrated material having a through hole and a particle packed layer. Examples of the integrated material having a through hole include a material having a circular through hole 16 as shown in FIG. 3, a material having a rectangular through hole, and a material having an indeterminate shape. The particle packed layer is roughly divided into a spherical particle packed layer and a non-spherical particle packed layer. The spherical particle packed layer is composed of beads packed particles 17 as shown in FIG. 4, and the non-spherical particle packed layer is indefinite. Examples thereof include particles and a cylindrical packing layer as shown in FIG. In order to maintain the reproducibility of the measurement, the transmission coefficient in the material should be as uniform as possible and the transmission coefficient can be easily calculated, which is also desirable in order to simplify the measurement. Therefore, it is particularly desirable to use a spherical particle packed layer for the material having through holes on the upper and lower surfaces used in the present invention. The material having the through-holes on the upper and lower surfaces is not particularly specified as long as the shape hardly changes up to the coal softening and melting temperature range, specifically up to 600 ° C.

The transmission coefficient of the material having through holes on the upper and lower surfaces needs to be set by estimating the transmission coefficient of coarse defects present in the coke layer. In the case where the transmission coefficient is 1 × 10 ⁸ to 2 × 10 ⁹ m ⁻² as a result of repeated investigations by the present inventors, such as consideration of coarse defect constituent factors and estimation of the size, which are particularly desirable for the present invention. Was found to be optimal. This transmission coefficient is derived based on the Darcy rule expressed by the following equation (1).
ΔP / L = K · μ · u (1)
Here, ΔP is the pressure loss [Pa] in the material having through holes on the upper and lower surfaces, L is the height [m] of the material having the through holes, K is the transmission coefficient [m ⁻² ], μ is the fluid. Viscosity [Pa · s], u is fluid velocity [m / s].

  It is inherently desirable that the penetration distance of the coal softening melt can be measured constantly during coal heating. However, since measurement is usually difficult at all times, after the coal softening melt has been infiltrated, the entire container may be cooled, and the actual infiltration distance after cooling may be measured instead. For example, it is possible to take out a material having through holes on the upper and lower surfaces from the cooled container and directly measure with a caliper or a ruler. Further, when particles are used as a material having through holes on the upper and lower surfaces, the softened melt that has permeated the interparticle voids fixes the entire particle layer to the permeated portion. Therefore, if the relationship between the mass and height of the particle packed bed is obtained in advance, the mass of the fixed particles can be derived by measuring the mass of the non-adhered particles after the infiltration, and the infiltration from there The distance can be calculated.

  Viscosity term (μ) is included in the above formula (1). Therefore, it is possible to estimate the viscosity of the softened melt that has penetrated into the material having through holes on the upper and lower surfaces from the parameters measured in the present invention. For example, when a coal sample is heated while maintaining a constant volume of a material having through holes on the upper and lower surfaces, ΔP is the pressure during penetration, L is the penetration distance, and u is the penetration speed. By doing so, the viscosity can be derived. In addition, when a constant load is applied to a coal sample and a material having through holes on the upper and lower surfaces and the coal sample is heated, ΔP is the pressure of the applied load, L is the penetration distance, u is the penetration speed, Viscosity can be derived by substituting into equation (1).

  The measurement example at the time of heating a coal sample and the material which has a through-hole in an up-and-down surface by fixed volume is shown. For 11 types of coal (A charcoal to K charcoal), the permeation distance and the pressure during permeation were measured. Table 1 shows the properties of coal used (average maximum reflectance: Ro, maximum fluidity: log MF, volatile content: VM, ash content: Ash).

  Using a device similar to that shown in FIG. 1, the permeation distance and the pressure during permeation were measured. Since the heating method is a high frequency induction heating type, the heating element 8 of FIG. 1 is an induction heating coil, and the material of the container 3 is a dielectric graphite. The diameter of the container 3 was 18 mm, the height was 37 mm, and glass beads having a diameter of 2 mm were used as the material 2 having through holes on the upper and lower surfaces. A coal sample 1 was prepared by weighing 2.04 g of coal pulverized to a particle size of 2 mm or less, charging it in a container, and dropping a weight of 200 g from above the coal 5 times at a fall distance of 20 mm to fill the coal. . Next, 9.36 g of 2 mm glass beads were weighed, and the glass bead packed layer disposed on the coal sample 1 was used as the material 2 having through holes on the upper and lower surfaces. A sillimanite disk having a diameter of 17 mm and a thickness of 5 mm was disposed on the glass bead packed layer, and a quartz rod was disposed thereon as the pressure detection rod 4. Nitrogen gas was used as an inert gas and heated to 550 ° C. at a heating rate of 3 ° C./min. During heating, the pressure applied from the pressure detection rod 4 by the load cell 6 was measured. After completion of the heating, cooling was performed in a nitrogen atmosphere, and the mass of the softened and melted coal and beads not fixed was measured from the cooled container 3.

The penetration distance was the filling height of the fixed bead layer. The relationship between the filling height and the mass of the glass bead packed bed was obtained in advance, and the glass bead filling height could be derived from the mass of the beads to which the softened and melted coal was fixed. The result is the following formula (2), and the penetration distance was derived from the formula (2).
L = (9.36−M) × 2.63 (2)
Here, L represents the permeation distance [mm], and M represents the mass of beads [g] not fixed to the softened and melted coal.

  The results of the penetration distance measurement are shown in Table 2, and the measurement results of the penetration distance with respect to the maximum fluidity (log MF) of the Giesera Plastometer method, which is a conventional softening and melting characteristic index, are shown in FIG.

  According to FIG. 6, the permeation distance has a certain degree of correlation with the maximum fluidity, but since there are many brands that are out of the correlation, the permeation distance is recognized as an index having a different tendency from the maximum fluidity. In particular, when Coal G and Coal H are compared in Tables 1 and 2, the maximum fluidity (log MF) shows almost the same value, but a large difference was found in the permeation distance. Since the measurement error of the penetration distance was a standard deviation of 0.5 as a result of performing the test three times under the same conditions, the difference between the penetration distances of Coal G and Coal H is 4.7, which is a significant difference. Considering that the penetration distance can simulate the coal softening and melting behavior in the coke oven, it can be said that the conventional Giesera plastometer method overestimates the softening and melting characteristics of coal G.

  If the permeation distance is a parameter indicating fluidity under conditions simulating softening and melting behavior in a coke oven, it is considered that this parameter is superior to the maximum fluidity measured by a Giesera plastometer. In order to confirm this, a coke strength comparison test was carried out on Coal G and Coal H having almost the same maximum fluidity and different penetration distances. In the conventional theory, the coke strength is mainly determined by the vitrinite average reflectance (average value of Ro) of coal and the maximum fluidity (Max Fluidity: MF) by the Giesera plastometer method (for example, Non-Patent Document 2). reference.). Therefore, 20% by mass of Coal G or Coal H is blended, and various coals are blended so that the vitrinite average reflectance (average value of Ro) and the maximum fluidity (log MF) of the entire blended coal are equal. The strengths of two types of coke produced from charcoal G and blended charcoal H) were compared. The coal blending conditions are shown in Table 3, and the blended coal properties average value is shown in Table 4.

The coke strength was evaluated by drum strength based on the rotational strength test method of JIS K 2151. 16 kg of blended coal adjusted to a particle size of 3 mm or less and 100 mass% and a water content of 8 mass% was charged to a bulk density of 750 kg / m ³ and dry-distilled in an electric furnace. After dry distillation at a furnace wall temperature of 1050 ° C. for 6 hours, nitrogen cooling was performed, and a drum strength test was performed. Based on the rotational strength test method of JIS K 2151, the mass ratio of coke having a particle size of 15 mm or more was measured at 15 rpm and 150 revolutions, and the mass ratio before rotation was calculated as the drum strength DI 150/15.

  The drum strength measurement results are shown in FIG. Compared with the blended coal G blended with the coal G, the blended coal H blended with the coal H showed higher drum strength. In the maximum fluidity by the Giesera plastometer method, since the softening and melting characteristics of coal G were overestimated, it is considered that the blended coal G became insufficient in fluidity and the drum strength was lowered. Therefore, it can be said that the fluidity of coal can be more appropriately evaluated by the penetration distance measured by the present invention.

  Moreover, the maximum pressure measurement result at the time of infiltration of each coal is shown together in Table 2. The maximum pressure shown in Table 2 is the result of pressure measurement in a measurement environment that simulates the expansion behavior in the coke oven, and is therefore effective as a parameter used for coke strength estimation and pressure estimation on the coke oven wall. I can say that.

  An example of measurement when a coal sample is heated by applying a constant load to the coal sample and a material having through holes in the upper and lower surfaces will be described. For the same 11 types of coal (A charcoal to K charcoal) as in Example 1, the permeation distance and the expansion coefficient during permeation were measured. Using a device similar to that shown in FIG. 2, the permeation distance and the expansion coefficient during permeation were measured. Since the heating method was a high frequency induction heating type, the heating element 8 in FIG. 2 was an induction heating coil, and the material of the container 3 was a dielectric graphite. The diameter of the container 3 was 18 mm, the height was 37 mm, and glass beads having a diameter of 2 mm were used as materials having through holes on the upper and lower surfaces. A coal sample 1 was prepared by weighing 2.04 g of coal pulverized to a particle size of 2 mm or less, charging it into the container 3, and dropping a weight of 200 g from the top of the coal 5 times at a fall distance of 20 mm to fill the coal. . Next, 9.36 g of 2 mm glass beads were weighed, and the glass bead packed layer disposed on the coal sample 1 was used as the material 2 having through holes on the upper and lower surfaces. A sillimanite disk having a diameter of 17 mm and a thickness of 5 mm was placed on the glass bead packed layer, and a quartz rod was placed thereon as the expansion coefficient detection rod 13. Nitrogen gas was used as an inert gas and heated to 550 ° C. at a heating rate of 3 ° C./min. During heating, the displacement was measured with a laser displacement meter, and the expansion coefficient was calculated from the height when filling the coal. After the heating, cooling was performed in a nitrogen atmosphere, and the mass of beads not fixed to the softened and melted coal was measured from the cooled container. The permeation distance was derived from the above equation (2).

  The osmotic distance measurement results are shown in Table 5, and the relationship between the osmotic distance measurement results and the maximum fluidity (Max Fluidity: MF) of the Giesera plastometer method is shown in FIG.

  According to FIG. 8, the permeation distance measured in this example has a certain degree of correlation with the maximum fluidity, but there are a plurality of brands that are out of the correlation, and it has been confirmed that the tendency is different. Considering that the measurement error of the penetration distance with this device was a standard deviation of 0.6 as a result of three tests under the same conditions, as in Example 1, coal G and coal with the same maximum fluidity A significant difference was observed in the penetration distance with respect to H. As for the drum strength, the blended coal H blended with the coal H was higher than the blended coal G blended with the coal G from the results measured in Example 1, so that the penetration measured by the method of the present invention was used. It can be said that the distance is an index that more appropriately evaluates the fluidity of coal than the maximum fluidity of the Giesera Plastometer method.

  Moreover, the final expansion coefficient measurement result of each coal is shown together in Table 5. The final expansion coefficient is a value of expansion coefficient at 550 ° C. The results in Table 5 are expansion coefficient measurement results in a measurement environment that simulates expansion behavior in a coke oven, and are effective as parameters used for coke strength estimation and estimation of the gap between the coke oven wall and the coke lump. It can be said.

DESCRIPTION OF SYMBOLS 1 Coal sample 2 Material which has a through-hole in the upper and lower surfaces 3 Container 4 Pressure detection rod 5 Sleeve 6 Load cell 7 Thermometer 8 Heating element 9 Temperature detector 10 Temperature controller 11 Gas inlet 12 Gas discharge port 13 Expansion detection rod 14 Weight 15 Displacement meter 16 Circular through-hole 17 Packing particle 18 Packing cylinder

Claims (4)

  A container is filled with a predetermined amount of coal to make a coal sample, and a material having through holes on the upper and lower surfaces is arranged on the coal sample, and the coal sample and the material having through holes on the upper and lower surfaces are kept at a constant volume. Meanwhile, when the coal sample is heated at a predetermined heating rate, the penetration distance of the molten coal that has penetrated into the through hole is measured, and the softening and melting characteristics of the coal are evaluated using the measured value. Evaluation method for softening and melting characteristics of coal.   A container is filled with a predetermined amount of coal to form a coal sample, and a material having through holes on the upper and lower surfaces is arranged on the coal sample, and the coal sample and the material having through holes on the upper and lower surfaces are kept at a constant volume. Meanwhile, when the coal sample is heated at a predetermined heating rate, the pressure of the coal transmitted through the material having through holes in the upper and lower surfaces is measured, and the softening and melting characteristics of the coal using the measured value Evaluation method for softening and melting characteristics of coal, characterized by   A container is filled with a predetermined amount of coal to form a coal sample, a material having through holes on the upper and lower surfaces is placed on the coal sample, and a predetermined load is applied to the material having the through holes on the upper and lower surfaces. When the coal sample is heated at a heating rate of, the penetration distance of the molten coal that has penetrated into the through hole is measured, and the softening and melting characteristics of the coal are evaluated using the measured value. Evaluation method of melting characteristics.   A container is filled with a predetermined amount of coal to form a coal sample, a material having through holes on the upper and lower surfaces is placed on the coal sample, and a predetermined load is applied to the material having the through holes on the upper and lower surfaces. A method for evaluating a softening and melting property of coal, comprising: measuring the coefficient of expansion of the coal when the coal sample is heated at a heating rate, and evaluating the softening and melting property of the coal using the measured value.

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