JP3250442B2 - Method and apparatus for measuring softening and melting properties of coal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for measuring the quality of coal used as a raw material for coke for metallurgy, particularly the softening and melting properties of coal.

[0002]

2. Description of the Related Art Coal is classified into caking coal which shows softening and melting properties by heating and dry distillation, and non-coking coal which does not show softening and melting properties.
Further, non-coking coal is also classified into fine coking coal and non-coking coal depending on the difference in cohesion. However, the fine coking coal and the non-coking coal may be collectively referred to as non-coking coal.

On the other hand, apart from the above-mentioned caking properties, the property of whether or not it becomes a robust coke is called coking property. In general,
The coking property largely depends on the caking property, and coal requiring high cohesion is used for those requiring strength such as coke for metallurgy. This caking property is quantified by measuring softening and melting properties such as fluidity. In the actual production of metallurgical coke, several types of coking coals are blended, and when determining the mixing ratio of each coking coal, the softening and melting properties of each coking coal are important factors to be considered in addition to the degree of carbonization.

[0004] As a method for evaluating softening and melting properties, a flowability test method using the Giesler plastometer method specified in JIS M 8801 has been conventionally known. In the Giesler plastometer method, a coal sample pulverized to a predetermined particle size is filled in a crucible, heated and heated in an electric furnace using a metal bath, and stirred by rotating a stir bar with a hook-shaped rotor. I do. The stirring rod is rotated at a constant torque, and the rotation speed is measured to determine the softening and melting characteristics.

FIG. 7 shows an outline of an apparatus used for this measurement. The rotation of the stirring rod 2 transmits the rotation of the motor 57 to one end of the clutch 58, adjusts the torque at the other end, and transmits the torque to the rotating shaft of the stirring rod. The rotation speed is measured by the rotation reading unit 59.

FIG. 8 shows the crucible 1 and its heating mechanism. A stirring rod 2 is arranged at the center of the crucible 1, and the crucible 1 is connected to a barrel 51 arranged at the upper part. Since volatile components are generated from coal during the test, the barrel 51 is provided with a gas outlet 52. The crucible 1 is immersed in a metal bath 53, and the metal bath 53 is heated by a heating wire 55 of an electric furnace 54. A thermocouple 56 is attached to the crucible 1,
The heating power can be controlled while measuring the temperature.

In the test, the temperature was raised at a heating rate of 3 ° C./min,
Measure the softening start temperature, maximum fluidity temperature, rotation speed, and solidification temperature. These measured values are the softening and melting characteristic values of the sample, and the maximum rotation speed is defined as the maximum flow rate and the maximum flow rate (M
F) is used as an index for softening and melting properties.

However, in the above-described method, the heating rate is small, and only the softening / melting characteristics in a low temperature rising state can be measured. While the above method measures the rotation speed by a constant torque method, a method of measuring the torque by a constant rotation method has also been proposed. For example, Japanese Patent Application Laid-Open No. 6-347392 discloses that a rotor is cylindrical, hemispherical, conical, or disk-shaped, and the rotor is heated at a heating rate of 3 ° C./min while rotating at a constant rotational speed. Heating and measuring the torque on the rotor is described.

[0009] In recent years, based on the finding that when the temperature of coal is rapidly increased, the fluidity of the coal when it is softened increases, non-coking or fine coal which has conventionally been considered unsuitable as a raw coal for metallurgical coke. Research has begun to use cohesive coal. That is, coal is heated to 400 ° C.
A process is being developed in which the viscosity of coal is increased by rapidly heating it to near 1000 ° C./min to increase the blending ratio of inexpensive and resource-rich non-fine caking coal.

In such a process, it is necessary to understand the softening and melting properties of coal under high-speed heating.
In particular, for coal with low fluidity, it is indispensable to distinguish and understand minute differences in the properties of the coal.

[0011]

However, the technique of JIS M 8801 described above and Japanese Patent Application Laid-Open No. 6-347.
In the technology of No. 392, the heating of the coal is performed by electric resistance heating using a heating wire, so that the heating speed is limited to about 3 ° C./min, and the technology of JP-A-6-347392 is also 3 ° C./min.
This technology measures the clay of a coal sample at a heating rate of about one minute, and it was not possible to distinguish and understand minute differences in the properties of coal with low fluidity due to rapid heating.

Accordingly, the present invention has been made to solve this problem, and has as its object to accurately measure the softening and melting properties of coal under rapid heating.

[0013]

Means for attaining the object include the following methods (1) and (2) for measuring the softening and melting properties of coal, and (3), (4) and (4). 5)
The apparatus for measuring the softening and melting property of coal described in (1).

(1) A method for measuring the softening and melting properties of coal, comprising the following steps: (A) filling a coal sample into a crucible equipped with a stirring rod,
(B) heating the coal sample in an inert gas stream at a heating rate of 1;
While heating at 0 ° C./min or more and 10,000 ° C./min or less, the stir bar is rotated at a constant torque to stir the coal sample, and (c) the rotation speed of the stir bar is measured. Processing using the temperature data of the coal sample,
(D) The softening and melting properties of the coal sample are determined from the processing results.

Since the rotation speed of the stir bar is measured while keeping the torque of the stir bar constant while heating the coal sample, the stir bar starts to rotate when the coal sample starts flowing, and when the coal sample reaches the maximum fluidity, the rotation speed is measured. Is the largest. In addition, since heating is performed in an inert gas stream, oxidation of the crucible and the coal sample is prevented, and stable measurement of the properties of coal is realized.

The softening and melting properties during rapid heating are examined by setting the heating rate during heating to 10 ° C./min or more and 10,000 ° C./min or less. This heating rate can be achieved by a high-frequency heating method described later. is there. The heating rate at the time of heating is 10 ° C. or higher, but program heating may be performed such that the temperature is maintained for a predetermined time during the heating and the temperature is raised again.

(2) A method for measuring the softening and melting properties of coal, comprising the following steps: (A) Filling a coal sample into a crucible equipped with a stirring rod,
(B) heating the coal sample in an inert gas stream at a heating rate of 1;
While heating at 0 ° C./min to 10,000 ° C./min, the stir bar is rotated at a constant rotation speed to stir the coal sample, and (c) torque of the stir bar is measured. Processing using the temperature data of the coal sample,
(D) The softening and melting name of the coal sample is obtained from the processing result.

The method of measuring the torque applied to the stirring bar while keeping the rotation speed of the stirring bar constant is different from the method described in (1). The flow of the inert gas and the rapid heating are the same as those described in (1).

(3) An apparatus for measuring the softening and melting properties of coal, comprising the members described below. (A) a cylindrical sleeve vertically provided with inlets for an inert gas at both ends, (b) a dielectric cylindrical crucible inserted into the sleeve, and (c) inside the crucible. (D) a stirrer equipped with a mounting mechanism, a rotation motor, a torque regulator, and a rotation speed detector for vertically attaching the rotation axis of the stirring rod to the axis of the crucible. A device, (e) an induction heating device surrounding the sleeve, a heating mechanism including a temperature detector and a temperature controller, and (f) a data processing device for processing data from the rotation speed detector and the temperature detector.

The sleeve is vertically arranged, and an inert gas is drawn in and out from outlets provided at both ends of the sleeve to create an inert gas flow. The stirring part of the stirring rod and the crucible containing the coal sample are inserted into this sleeve. An inert gas stream flows between the inner wall of the sleeve and the outer wall of the crucible. The crucible must be dielectric, for example, to allow high frequency induction heating.

The stirring rod is attached to the stirring device. The rotation axis of the stirring rod is adjusted to the axis of the crucible by an attachment mechanism, and the stirring part is adjusted so as to be arranged at a predetermined position. Then, the rotation of the rotation motor provided in the stirrer is transmitted to the stirrer rod at a constant torque via a torque adjuster.
The rotation speed of the stirring rod is measured by a rotation speed detector.

The heating means heats the coal sample at a specified rate while measuring the temperature of the coal sample. The temperature of the coal sample is measured by a temperature detector, and the temperature controller controls the output of the high-frequency generator to regulate the current flowing through the induction heating coil and perform a specified temperature rise. The data processing device processes the sent rotation speed data and temperature data to obtain a softening start temperature, a maximum flow rate temperature, a re-solidification temperature, and a maximum flow rate. The heating method is preferably a high-frequency induction method,
An electric current is instantaneously induced in the crucible, which is a dielectric, and the crucible is heated.
/ Minute rapid heating is possible, and programmed heating that changes the heating rate during heating can be easily performed.

(4) An apparatus for measuring the softening and melting properties of coal, comprising the members described below. (A) a cylindrical sleeve vertically provided with inlets for an inert gas at both ends, (b) a dielectric cylindrical crucible inserted into the sleeve, and (c) inside the crucible. (D) a stirrer provided with a mounting mechanism, a rotation motor, a rotation speed controller, and a torque detector, wherein the rotation shaft of the stirrer rod is fitted to the axis of the crucible and vertically mounted. A device, (e) an induction heating device surrounding the sleeve, a heating mechanism comprising a temperature detector and a temperature controller, and (f) a data processing device for processing data from the torque detector and the temperature detector.

This measuring device performs the rotation of the stirring rod at a constant torque while the device described in (3) performs the rotation of the stirring rod at a constant torque. The difference from the device described in (3) is that the stirring device is provided with a rotation speed controller instead of the torque controller and a rotation torque detector instead of the rotation speed detector.

(5) The apparatus according to (3) or (4), wherein the sleeve comprises a quartz tube, and the crucible filled with the coal sample comprises graphite.

In the rapid heating, the heating temperature may exceed 1000 ° C. in some cases. The quartz tube is a heat-resistant and practical material, and since it is non-dielectric, loss of high-frequency current can be prevented. Graphite is the most heat-resistant practical material and is chemically stable in an inert gas atmosphere. That is, under conditions of high-frequency induction heating and an inert gas atmosphere, the quartz tube sleeve and the graphite crucible are excellent.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described with reference to the drawings. FIG. 1 schematically shows an apparatus for stirring a coal sample with a constant torque and measuring the rotation speed of a stirring rod. The test procedure is as follows. The stirrer 21 of the stirrer rod 2 is inserted into the crucible 1, the coal sample is filled, the sample is pressed with a predetermined pressure, the crucible lid 24 is closed, and the crucible 1 is set with its axis aligned with the axis of the sleeve 20. Then, the stirring rod 2 is attached to the stirring device 10. Next, the outlet 22 of the sleeve 20
Inert gas is blown from

The shape of the stirring section 21 may be a hook-and-cross shape, but a disk-shaped, cylindrical-shaped, conical-shaped or top-shaped one having a large contact area with the coal sample is desirable from the viewpoint of improving accuracy. The stirring rod is preferably made of metal, graphite, ceramics and the like having heat resistance and high torsional strength, and finished without eccentricity.

As the inert gas, argon, nitrogen or the like is used. The lid 24 of the crucible 1 has a hole through which the stirring rod 2 passes and a hole through which the thermometer 36 passes, and volatile components generated by heating are carried away by the inert gas stream through these holes. The lid 24 can also prevent the coal sample from spilling out of the crucible 1 when it expands too much.

The torque adjuster 12 of the stirring device 10 is adjusted in advance so that the torque becomes a predetermined value. As a result, the rotation of the rotary motor 57 is not transmitted directly to the stirring rod 2, and the rotation is stopped when the torque applied to the stirring rod 2 is larger than the adjustment value, and the rotation speed increases as the torque decreases. The rotation speed of the stirring rod 2 is measured by a rotation speed detector 13.

The heating means 30 surrounds the outside of the sleeve 20 with, for example, an induction heating coil 31. Preferably, the induction heating coil 31 is excited by a high-frequency current from a high-frequency generator 32 to generate an induction current in the crucible 1. Heat directly. For this reason, heating is performed instantaneously and rapid temperature rise becomes possible.

The rate of temperature rise is controlled by the temperature controller 33, and a programmed temperature controller may be used for this. The temperature controller 33 controls the high-frequency generator 32 so that a temperature rise rate program is input in advance, a temperature signal is received from the temperature detector 34, and the temperature is raised in accordance with the program.

A thermometer 35 for detecting the temperature of the crucible 1 and a thermometer 36 for detecting the temperature of the coal sample are connected to the temperature detector.
It is better to use the temperature of the crucible 1 detected at 5. The temperature of the coal sample detected by the thermometer 36 may fluctuate in a short cycle depending on the generation state of volatile components, and is not suitable for a signal for control.

The temperature of the coal sample detected by the thermometer 36 is sent to the data processing device 40. Data processing device 4
To 0, the temperature of the coal sample and the rotation speed from the rotation speed detector 13 are sent, where data processing is performed.

The data processing will be described with reference to FIG. The data processing device 40 plots the temperature data and the rotation speed data that are sent every moment on the time axis. In the figure, the horizontal axis is the time axis representing the passage of time, and the vertical axis is the temperature axis on the left side and the rotation speed axis on the right side. The unit of the rotation speed ddpm is a unit used in the JIS, and 1 d
dpm is 0.01 revolutions per minute.

A mountain-shaped graph M is obtained from the rotation speed data, and a linear graph L is obtained from the temperature data. The temperature rise rate is constant at 1000 ° C./min, and the rotation speed changes as follows with the temperature rise. The stirring bar starts to rotate from the point A, the rotation speed becomes maximum at the point B, and the rotation stops at the point C. The temperature at the time when point A was reached can be read from graph L and is about 400 ° C., which is the softening start temperature. Similarly, the maximum fluidity temperature can be read from point B, and the re-solidification temperature can be read from point C. The rotation speed read from the coordinate of the vertical axis of the point B is the highest fluidity.

As described above, the case of the constant torque measurement has been described.
In the constant rotation speed measurement, the rotation speed adjuster and the rotation torque detector are used instead of the torque adjuster and the rotation speed detector as described above. Therefore, the torque data and the temperature data are sent to the data processing device for processing. However, when the coal sample is solidified, excessive torque may be applied to the stirring rod. Therefore, it is desirable to provide a safety clutch in the rotating motor.

[0038]

[Example] Maximum flow rate (MF) by JIS method is 1 to 40
About 10 kinds of brands of non-slightly caking coal and caking coal of about 00, the softening and melting properties were examined by a constant rotation method while changing the heating rate from 10 ° C / min to 10000 ° C / min. The apparatus used was the apparatus shown in FIG. 1 and a rotational speed adjuster was used in place of the torque adjuster, and a rotational torque detector was used in place of the rotational speed detector. By rotating the stirring rod at a constant rotation speed, the change in torque due to temperature rise is detected, and the softening start temperature,
The maximum fluidity temperature, resolidification temperature and minimum torque were determined.
Table 1 shows the properties of the coal samples used.

[0039]

[Table 1]

The other conditions are as follows. Sleeve: quartz, inner diameter 28 mm, outer diameter 32 mm, length 220 mm Crucible: graphite, inner diameter 14 mm, depth 12 mm Stirring rod: made of SUS316, the stirrer is 13 mm in diameter and 3 mm in thickness, disk type Sample amount: 1.0 g sample Particle size: 35 mesh or less 100% Packing density: Bulk density 850 kg / m ³ Rotation speed: 0.1 rpm Inert gas: Nitrogen, flow rate 5.0 NL / min

Of the profiles obtained by the measurement, as typical examples, the heating rate is 100 ° C./min, 1000 ° C./min.
3 to 5 are shown in FIGS. In the figure, a graph M shows a change in torque, and a graph L shows a sample temperature. Point A is the softening start temperature, point B is the maximum fluidity temperature, point C is the resolidification temperature, and the torque value indicated by point B is the minimum torque value.

FIG. 3 shows the case where the temperature is increased at 100 ° C./min.
Softening start temperature is 400 ° C, maximum fluidity temperature is 555 ° C,
The re-solidification temperature was 605 ° C, and the minimum torque value was 7.5 mNm. FIG. 4 shows the case where the temperature was increased at 1000 ° C./min. The softening start temperature was 410 ° C., the maximum fluidity temperature was 580 ° C., the re-solidification temperature was 625 ° C., and the minimum torque value was 3.7 mNm. FIG. 5 shows the case where the temperature was raised at 1800 ° C./min. The softening start temperature was 415 ° C., the maximum fluidity temperature was 610 ° C., the re-solidification temperature was 630 ° C., and the minimum torque value was 2.0 mNm.

As described above, the minimum torque value as an index of the fluidity varies depending on the heating rate, but according to the present invention, the softening and melting at an optional heating rate in the range of 10 ° C./min to 10,000 ° C./min. Sex can be measured. It is also clear that the measurement can be performed at a low heating rate of less than 10 ° C./min.

FIG. 6 shows the minimum torque values measured for the ten types of coal samples shown in Table 1 while changing the heating rate. As can be seen from the figure, even for brands with a large minimum torque value when the temperature rise rate is low, the minimum torque is reduced by the rapid temperature rise, and the fluidity is improved. In addition, when the heating rate increases, the order of the minimum torque value is reversed depending on the brand. According to the present invention, the melting characteristics of the coal during such rapid heating can be determined.

[0045]

As described above, according to the present invention, a coal sample is heated at a temperature of 10 ° C./min or more in an inert gas stream.
The softening and melting properties are measured while heating at a heating rate of 0000 ° C./min or less. For this reason, the softening and melting properties of coal during the production of coke by rapid heating can be reliably grasped, and valuable information can be provided in determining the mixing ratio of non-coking coal. . As described above, the effect of the present invention that contributes to the development of coke manufacturing technology is great.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an apparatus for describing an embodiment of the present invention.

FIG. 2 is a graph illustrating a relationship between rotation speed and temperature for explaining data processing.

FIG. 3 is a graph showing a relationship between a torque and a temperature when a heating rate is 100 ° C./min.

FIG. 4 is a graph showing the relationship between torque and temperature when the temperature is raised at a rate of 1000 ° C./min.

FIG. 5 is a graph showing the relationship between torque and temperature when the temperature is raised at a rate of 1800 ° C./min.

FIG. 6 is a graph showing a relationship between a heating rate and a minimum torque value.

FIG. 7 is a schematic diagram showing the concept of a conventionally used device.

FIG. 8 is a vertical sectional view of a heating unit of a conventionally used device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crucible 2 Stirrer rod 10 Stirrer 11 Attachment part 12 Torque adjuster 13 Rotational speed detector 20 Sleeve 21 Stirrer 22, 23 Outlet 24 Crucible lid 30 Heating means 31 Induction heating coil 32 High frequency generator 33 Temperature controller 34 Temperature Detector 35, 36 Thermometer 40 Data processing device 57 Rotary motor

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideki Tsunoya 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References Motoichi Fukuhara "Japanese Industrial Standards JIS Coal-Testing Method" Japan Industrial Standards Association, published on September 30, 1993 No. 15-1 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 25/04 G01N 33/22 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A method for measuring the softening and melting properties of coal, comprising the following steps: (A) charging a coal sample into a crucible provided with a stirring rod; (b) heating the coal sample in an inert gas stream at a heating rate of 1
While heating at a temperature of 0 ° C./min or more and 10,000 ° C./min or less, the agitating rod was rotated at a constant torque to stir the coal sample, and (c) the rotational speed of the agitating rod was measured. Rotation speed data is processed using the temperature data of the coal sample, and (d) softening and melting properties are obtained from the result of the processing.