JPS61161454A - Method for quick measurement of caking property of coal - Google Patents

Abstract

PURPOSE:To measure quickly the caking property of coal with high accuracy by packing coal particles having a specific grain size into a capillary, heating the particles at a specifically high heating up rate and measuring the expansion height of the coal. CONSTITUTION:The coal 2 is pulverized to 250-840mum grain size and is packed into the metallic or glass capillary having about 5-12mm inside diameter. The height thereof is designated as lo. The coal is then heated at 10-250 deg.C/min heating up rate to 470-550 deg.C and to allow the coal particles to expand freely. The height of expanded coal is designated as height ld. The caking property of the coal are determined from the measured values of the height lo before the expansion and the height lo+ld after the expansion. Since, the coal is quickly heated by the capillary, the uniform heating is made possible and the expansion is measured with good accuracy without scattering of the coal particles by the generated steam and cracking gas. The quick determination of the caking property with high accuracy is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for measuring caking property, which is important for evaluating the quality of raw material coal for coke production.

Conventional technology and its problems One of the important issues in the coke manufacturing industry in recent years 1, +-
4-El f /; /7”l! e j &# /
7-14 111% M -1/y? fl
# θ) It is to simultaneously achieve stabilization and efficient operation of the coke oven. In order to deal with this issue, for example, in Japan, automation of combustion management is being promoted with the aim of uniformly carbonizing coke and reducing the amount of heat of carbonization, while automation of property analysis of coal and coke is also being progressively promoted to ensure stable coke quality. This is reflected in the

By the way, as is well known, the factors that control coke quality include coal properties and carbonization conditions, and among them, the caking property of coal is cited as a major factor. Therefore, in order to stabilize coke quality, it is effective to quickly and accurately grasp the caking property of coal and reflect it in the quality adjustment of coal charged in a coke oven.

There are various methods for measuring the caking properties of coal, but the one that is widely used and put into practical use worldwide is a.

Crucible expansion test method (button method, C3N), b, with flow - L/-h commonly used in Japan - J
These are the Zeeter method and the Gieseler plastometer method specified in IS M2SO4.

However, both the G-Eater method and the Gieseler Plastometer method have a slow heating rate of 3°C/min, and the measurement procedure is complicated, so the time required for measurement is long and the quality of coke cannot be controlled. It is not suitable for measurements that require rapidity. On the other hand, in the Button method, a sample is placed in a predetermined crucible, rapidly heated at a high temperature of 820°C ± 5°C, and the shape and size of the coke produced is compared with that of a standard crucible and expressed as the Button index. It is widely used because measurements can be made easily and quickly.

However, in the case of this Button method, since the Button index is a rough value in 1/2 increments, it is rarely used for actual operational management, and is usually used as a reference value.

In addition to the above-mentioned button method, the Lessing method and the Nenko method, which is a slightly improved version of the Lessing method, are known as methods for rapidly measuring the caking properties of a single coal.

For example, in the Nenken method, 1f of nine coals pulverized to a particle size of 250μm or less is 100mm in length, 1:9m in inner diameter, and 15+m in outer diameter.
After filling the sample into a quartz tube and making the sample surface horizontal by tapping the tube, a 6.5F quartz weight was loaded onto the sample surface and the tube was placed in a vertical tube maintained at a temperature of 600℃. The coal is charged into an annular electric furnace, held for 7 minutes, then taken out, and the ratio of the height of the coal after heating and expansion to the filling height of the coal before heating is determined and used as an index of caking property.

However, in this method, because the diameter of the thin tube is large, the heating of the coal is uneven between the part near the tube wall and the center.
Buffiness occurs due to the expansion of the coal, and buffiness also occurs because the packing density of the sample is not specified. Also,
Due to the high holding temperature of the electric furnace, 1.Depending on the type of coal, the sudden generation of steam and pyrolysis gas during heating may cause a type of bumping phenomenon in the coal sample, causing the coal to scatter and impairing measurement accuracy.1. Measured values lacked reproducibility.

Furthermore, the loaded quartz mold may solidify with the molten and expanded coal, making post-processing work after measurement difficult.
There were many flaws in the measurement method.

For this reason, the Lessing method and the Nenken method are hardly put to practical use.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional situation, and its purpose is to devise a method for quickly and accurately grasping the caking properties of coal. .

Structure of the Invention The method for measuring the caking property of coal according to the present invention is characterized in that the maximum particle size is 8.
Coal pulverized to 40 μm or less and 250 μm or more with an inner diameter of 5
~12Ialt metal or glass bottomed tube with a charging density of 1. Fill below Of/al 1. After heating the coal to a temperature of 470 to 550°C at a heating rate of at least 10°C/min to 250°C/min to cause free expansion, the height of the coal after expansion or the filling height of the coal before heating The method is characterized by measuring the ratio of the expansion height of the coal after heating to the expansion height of the coal after heating, and using the measured value as an index of caking property.

In other words, this invention utilizes the knowledge that the expansion of coal is highly dependent on the heating rate to determine the caking properties of coal, without molding the coal sample as in the conventional jitmeter method.
This is a method in which the coal is directly filled into a thin tube and rapidly heated at a heating rate of 10'C/min or more and 250°C/min or less to expand the coal.

When measuring the degree of expansion of coal under such rapid heating conditions, it is necessary to heat the coal uniformly and to suppress the scattering of coal particles due to the common belief that water vapor and pyrolysis gases are generated during heating. This is extremely important.

In order to solve these problems, the inventors conducted many experiments and discovered conditions under which reproducible measurement values could be obtained.

First, in order to uniformly heat the coal, the inner diameter of the thin tube filled with the coal sample should be 5 to 12 mm. The reason for this is that when the inner diameter of the tube becomes larger than 12 m, the heating of the coal becomes uneven between the part close to the wall surface and the center part, and the expansion of the stone tip becomes uneven. In addition, if the diameter is extremely small, less than 5 m, smooth expansion of the coal will not be achieved and the measured values will be uneven.

On the other hand, it is necessary to facilitate the deviation of the stone #1 particle from 1pkfJ-barka+LIfμΔl7 and to adjust the pulverized particle size of the coal. For this reason, in this invention, the pulverized particle size of coal is limited to a maximum particle size of 840 μm or less and 250 μm or more. That is, when the diameter is 250 μm or less, the scattering of coal particles increases, which causes variations in measured values. On the contrary, 1
This is because it has been found that even if the coal particle size is too large, the quality deviation of the sample has a large effect, and that if it exceeds 840 μm, the measured values will vary.

In addition, in this invention, when filling a thin tube with coal having the above-mentioned particle size, the charging density is set to 1. The reason why we decided to adjust the temperature to below Of/aII was to obtain reproducible measurement values because increasing the charging density inhibits the smooth departure of the generated gas, causing a bumping phenomenon and scattering coal particles. For this reason, this invention ÷ is the coal charging density of 1.Of/
It was limited to cr' or less. Further, the reason why the heating rate at this time was set to 106 C/min or more and 250' C/min or less was because it was confirmed that the detection sensitivity of the expansion coefficient was high in this heating rate range.

The heating temperature is set at 470°C, when the expansion of the coal is completed.
Heat to a temperature of ~550°C.

This invention relates to the height of the expanded coal obtained by collapsing the coal or the expansion height of the heated coal relative to the filling height of the unheated coal under measurement conditions set within a range that satisfies the above conditions. The ratio is measured and this measured value is used as an index of caking property.

In other words, the ratio of the expansion height of the heated coal to the coal height after expansion or the coal filling height before heating has high repeatability and also has a high correlation with the expansion rate measured by the conventional diphthometer method. This is because it was found that it can be fully used as an indicator of the caking property of coal.

The method of this invention will be explained based on FIGS. 1 and 2. Coal (2) pulverized to a maximum particle size of 840 μm or less and 250 μm or more is placed in a metal or glass bottomed tube (1) with an inner diameter of 5 to 12I. ) is packed to a predetermined density of 1.097i or less. The filling height of coal at that time is 10
shall be. Next, the expansion of the coal through the thin tube is completed 470
25 at least 10°C/min up to a temperature of ~550°C
Rapid heating at a heating rate of 0°C/min or less. As a method for rapidly heating the coal, an annular electric furnace or a metal bath heated to a predetermined temperature can be used, an infrared image furnace, a microwave heating furnace, etc. can be used.

Figure 2 shows the state after the coal is rapidly heated to a predetermined temperature and allowed to freely expand. 3)
becomes. In this invention, the height of the coal after expansion is jo+
/d) Alternatively, the ratio of the expansion height /d of the coal after heating to the filling height to of the coal before heating is measured and used as an index of the caking property of the coal.

The heating temperature of the coal in the thin tube (1) can be measured in advance by inserting a thermocouple into the thin tube.

Example 1 Among the three types of coal shown in Table 1, the blended coal used in the production of blast furnace cocoon was used. Pulverized coal was placed in a thin tube made of heat-resistant glass with an inner diameter of 10 m and a length of 120 m at a height of 20 mm. Then, the tube was filled with a charging density of 0.7 f/al, and immersed in a metal bath with a capacity of 500℃ to a height of 100 corners from the bottom of the narrow tube, and the heating rate was adjusted. The coal was heated at a target rate of 100° C./min, taken out after 4 minutes, and the expansion height of the coal was measured, and the ratio of the expansion height of the coal after heating to the filling height of the coal before heating (20 m) was determined.

Using the above method, the blended coal shown in Table 1 was crushed to a particle size of 1680μ.
m or less, 840 μm or less, 250 μm or less, 149 μm
Each coal was pulverized and adjusted as follows, and the swelling degree was measured five times. The average value ('5c) and variation range (R) of these measurement results are shown in Table 2.

As is clear from the results in Table 2, the pulverized particle size was 168゜μ.
m or less, the average expansion height and expansion ratio [(X
) is not significantly different from the pulverized particle size of 840 μm or less and 250 μss or less, but the variation range (R) is large. This is presumed to be because when the pulverized particle size is coarse, the influence of the difference in properties of each coal particle size becomes noticeable. On the other hand, if the pulverized particle size is 149 μm or less, the average value (X) of the expansion height and expansion ratio is low and the fluctuation range (R) is The particle size is larger than that of 840 ttna or less and 250 μm or less.

Therefore, the pulverized particle size of coal during rapid heating is as follows:
It can be seen that a maximum particle size in the range of 840 to 250 μm is appropriate.

Table 1 (blank below) Table 2 Example 2 When pulverizing the blended coal shown in Table 1 to a pulverized particle size of 250 μm or less and determining the degree of expansion fAll in the same manner as in Example 1, the coal charging density of the thin tube 0.50. ,0.70.1.0
0.1.10 f/as” respectively and fill.
Table 3 shows the results of five expansion measurements for each charging density. The height of coal filling was constant at 20 wr.

As is clear from the results in Table 3, the filling height is 20wa.
Therefore, as the charging density increases, the amount of charged coal increases, and the average value (X) of the expansion height and expansion ratio increases sequentially, but when the charging density is 1.1 (1/ In the case of i, the variation range (R) is significantly increased compared to the case where the charging density is 1.00 f/al or less.This is because the charging density is 1.00 f/al or less.
If it becomes higher than 00 f/a1a, the escape of the generated gas will be inhibited, the gas pressure in the filled sample will increase, a bumping phenomenon will occur, the sample will be lifted irregularly, and the fluctuation range (R) will become large. It is inferred. Therefore, it can be seen that the appropriate charging density of coal is 1.0 fld or less.

Table 3 Implementation Example 3 The coal blend shown in Table 1 was pulverized to a particle size of 250 μm or less, and the coal charging density in the tube was 0.70 f/aIl.
When measuring the degree of expansion using the same method as in Example 1 under the conditions of filling height 20cm and filling height, the inner diameter of the heat-resistant glass thin tube used was changed to 4, 6, 10, 12, and 13cm. Table 4 shows the results of measuring the expansion degree of the thin tube five times.

As is clear from the results in Table 4, the tube diameters are 4 and 13.
In the case of m, the expansion degree is abnormally large or small compared to the expansion degree of other thin tube diameters. This is because if the diameter of the tube is too small, such as 4 m, the smooth escape of the generated gas will be inhibited.
The gas pressure inside the filled sample increases and is lifted abnormally.
It is presumed that it exhibited a large degree of expansion. On the other hand, if the tube diameter d (13 sm) is too large, a large temperature difference will occur between the tube wall side and the center of the sample inside the tube during rapid heating, and uniform coal expansion will not occur and the fluctuation range (R) will decrease. It is inferred that the coal had a large degree of expansion.From these results, it can be said that a diameter of the thin tube of 5 to 12 m is an appropriate size for measuring the degree of expansion of coal with good reproducibility.

Table 4 Example 4 The coal blend shown in Table 1 was crushed with a particle size of 250 μm or less (4) and charged into a heat-resistant glass tube with an inner diameter of 10 ia and a length of 120 m at a density of 0.70 f/♂. The coal was filled to the height of the coal, and the heating rate was varied using an infrared image furnace with an air capacity of 11M, and after reaching 500°C, it was held for 3 minutes to cool down to room temperature, and then taken out of the furnace and the degree of expansion of the coal was measured. The results are shown in Table 5.

As is clear from the results in Table 5, although the higher the heating rate, the higher the acoustic tension tends to be, the degree of expansion at 3° C./min was only slightly detected.

On the other hand, a heating rate of 10° C./min to 250° C./min shows a large *tonicity, indicating that both detection sensitivity and accuracy are good. However, at a heating rate of 250°C/min or higher, the stiffness increases, but the variation range (
R) is large and measurement accuracy deteriorates.

This is thought to be because if the heating rate becomes too high, the amount of gas generated per unit time becomes too large, the gas pressure within the sample becomes high, a bumping phenomenon occurs, and the sample is lifted irregularly. Therefore, the heating rate is 10℃/
It is determined that a value of 2506 C/min or more and 2506 C/min or less is desirable.

(Margin below) Table 5 Example 5 Using three types of samples containing the coal blends shown in Table 1, Example 4
Table 6 shows the results of measuring the degree of expansion using the same method as above.

Note that the heating rate of the infrared image furnace was kept constant at 100° C./min.

From the results in Table 6, the variation range of expansion degree is small for all coal types and the reproducibility is good, and the total expansion rate shown in Table 1 and the values measured by the method of this invention tend to be good. It can be seen that they match.

Table 6 Effects of the Invention As is clear from the above examples, according to the method of this invention, scattering of coal particles can be suppressed under rapid heating conditions, and reproducible measured values can be obtained. Since it can be measured simply and quickly, it is far more useful than ever and greatly contributes to stabilizing coke quality.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams showing the method for measuring coal caking properties according to the present invention, where Figure 1 is a vertical cross-sectional view of a thin tube showing the state before lime heating, and Figure 2 is a longitudinal cross-sectional view of a thin tube after heating coal. FIG. 3 is a longitudinal cross-sectional view of the cylindrical tube showing the state. 1... Thin tube, 2... Coal before heating, 3...
Expanded coal. Spontaneous procedural amendment August 23, 1985 Mr. Michibu Uga, Commissioner of the Patent Office, 1985, Patent Application No. 1926, 2, Title of invention: Method for rapidly measuring coal caking property 3, Amendments made. Relationship to the case of the applicant: Sumitomo Metal Industries Co., Ltd. 4, Agent 5, 5-15 Kitahama, Higashi-ku, Osaka (211) Date: Showa, Month, Day 1
, in Table 2 on page 12 of the present specification, the average value (x) of the expansion height for grain sizes of 149 μm or less, r17.4J, is corrected to r7.4J. 2. In Table 4 on page 15 of the same specification, m pipe inner diameter Cl11)
5" is corrected to "6". 3. Table 5 on page 17 of the same specification shows the heating rate ('C/min)
Add the results of 250 and 300 as shown below. "Table 5

Claims (1)

[Claims] Coal pulverized to a maximum particle size of 840 μm or less and 250 μm or more is packed into a metal or glass bottomed tube with an inner diameter of 5 to 12 mm at a charging density of 1.0 g/cm^3 or less, and the coal is heated at least 10° C./cm3 or less. After heating to a temperature of 470 to 550°C at a heating rate of 250°C/min or more for free expansion, the expansion height of the coal after heating relative to the height of the coal after expansion or the filling height of coal before heating. 1. A method for rapidly measuring the caking property of coal, characterized by measuring the ratio of coal viscosity and using the measured value as an index of the caking property.