JPS61189437A - Measuring method of bulk density of coal - Google Patents

Abstract

PURPOSE:To calculate bulk density simply with precision close to the actual furnace condition by charging a coal sample into a cylindrical sample vessel and compressing it with a piston in the vessel and measuring the relation between the applied pressure and the bulk density. CONSTITUTION:The coal sample of the quantity more than the volume of the sample vessel 2 is charged into the vessel 2 and the excessive sample of the upper surface of the vessel 2 is cut and the weight of the sample is weighed. This vessel 2 packed with the sample is loaded on a load cell 1 and the relation between the dropping distance of the piston 3 and the applied pressure is recorded with a recorder 5 by lowering the piston 3 at the specified speed. Since the packed volume of the sample is obtained from the dropping distance, the bulk density is calculated from the calculated sample weight in advance. Consequently, the bulk density for the applied pressure corresponding to the impressed force of the actual furnace is calculated immediately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for accurately determining the bulk density of coal charged in a coke oven from a small amount of sample.

BACKGROUND ART - The bulk density of granular coal charged into a coke furnace varies depending on the type of coal, moisture content, particle size, amount of oil added, furnace height, etc. If the bulk density of the charged coal in the furnace fluctuates, the amount of charged coal will not be constant, which will not only result in excess or deficiency in coke production, but also affect the coke quality, the amount of heat required for carbonization, etc. It is necessary to know the bulk density of coal in a coke oven before charging the coal.

Conventionally, the ASTM bulk density measurement method for this purpose has been used.
D-291 is used, and this standard specifies that the falling pressure #11 (distance between the damper at the bottom of the hoff bar and the top of the receiver) is 5591, and the sample amount per run is 34 kg.

The problem that the invention aims to solve However, the measurement method according to the above ASTM.

Due to the large amount of samples, one person cannot work alone, resulting in poor workability, and there is poor correspondence between drop impact from a specified distance and drop impact during charging into an actual reactor. There is a problem in that the measured value and the actual bulk density in an actual reactor are slightly different.

Therefore, the inventor of the tree attempted to improve the compatibility with the bulk density of an actual furnace by changing the falling distance in the above ASTM method.

FIG. 5 is a relationship diagram at that time, where the horizontal axis is the falling distance and the vertical axis is the bulk density. According to this relational expression, the measured value of the bulk density of a certain coal sample at a falling distance of 559 cm specified by ASTM is equal to the bulk density of the charged coal in an actual furnace of 0.
It was found that the falling distance according to the ASTM method had to be set to about 2 m in order to obtain a measured value that was significantly different from 72 to 0.73 Kg/l and almost coincided with the bulk density of an actual furnace.

However, in the ASTM method, increasing the falling distance of the charged coal beyond the current standard will further deteriorate the workability, so it is difficult to adopt this method in reality.

The present invention has been made to solve the above-mentioned problems. Means for solving the problems The present invention is.

``A coal sample is charged into a cylindrical sample container, and the sample in the container is compressed with a piston, and the relationship between the pressurizing force and bulk density is measured, and from that relationship, when charging into an actual furnace. A method for measuring the bulk density of coal, which is characterized by determining the bulk density at an applied force equivalent to the impact force of I came to the conclusion that I could ask for it.

The present invention will be explained in detail below.

Unlike the above-mentioned ASTM method, which takes into account the impact force caused by the falling coal sample, the present invention uses the pressurizing force when compressing the coal sample with a piston to respond to the impact force caused by the falling coal charged in the actual furnace. The purpose is to find out the density.

FIG. 1 is a front view showing an example of an apparatus suitable for use in the measuring method of the present invention.

(1) is a load cell as a pressure detector, and (2) is a cylindrical sample container for filling with a coal sample. (3) is a piston for pressurizing and compressing the sample in this sample container, and the diameter of the piston is set to be slightly smaller than the inner diameter of the sample container (2). (4) is a lifting screw for raising and lowering this piston (3). In addition, a recorder (5) displays the descending distance and pressing force of the piston (3).
) is attached.

To measure the bulk density of coal using this measuring device,
First, a coal sample in an amount larger than the volume of the sample container (2) is charged, and after cutting off the excess sample on the top surface of the container (2), the weight of the sample is measured. Next, this sample filling container (2) is placed on the load cell (1), the piston (3) is lowered at a constant speed, and the relationship between the descending distance of the piston (3) and the applied pressure is recorded. Record in total (5). Sample container (
Since the volume of 2) is fixed, the volume of the filled sample may be directly taken instead of the descent distance.

From the chart on the recorder (5) after measurement, read the descending distance of the piston (3) or the filling volume of the sample corresponding to the pressing force equivalent to the impact force during charging in the actual furnace, and calculate the amount determined previously. Calculate the bulk density from the sample weight.

Example The bulk density of the coal sample was measured under the following conditions.

Sample container diameter 100 as, height 70 am, volume 550 cc
The weight of the sample charged into the sample container is 700 g (cut off the overflow). The descending speed of the piston is 10 m. The measurement results are shown in Figure 2, where the horizontal axis is the pressure force and the vertical axis is the bulk density. be.

It can be seen that this result agrees well with the result shown in FIG. 5 described above. Therefore, even if you do not use the ASTM method, which has poor workability, you can use this simple measurement method to apply the same coal sample to this actual furnace from a pressure equivalent to the impact force of an actual furnace (for example, 30 g/cmz). The bulk density (for example, 0.73 Kg/l) when the coal is charged can be immediately determined.

Example 2 Measurements were carried out under the conditions described in Example 1, and the impact force of coals with various moisture contents was equivalent to that of an actual furnace when 0.3% oil was added and when no oil was added. The bulk density was determined. The sample coal used was one in which 85% of the particles had a particle size of 3 mm or less.

The results are shown in Figure 3. In Figure 3, the dotted line indicates an oil concentration of 0.3
%, and the solid line is the case when no oil was added.

From the results shown in Figure 3, it is easy to understand the effect of factors on the moisture content of the charged coal and the bulk density of the amount of oil added.

Example 3 Measurements were carried out under the conditions described in Example 1, and the bulk density corresponding to the impact force in an actual furnace was determined for coal with a moisture content of 9% when the proportion of particles with a particle size of 3 layers or less was changed. .

The results are shown in Figure 4.

From the results shown in Figure 4, the effect of the grain size of the charged coal on the bulk density can be easily understood.

Function According to the present invention, the bulk density corresponding to the impact force of falling of the charged coal in an actual furnace can be determined by the pressure applied when the coal sample is compressed by the piston.

Effects of the Invention According to the present invention, the bulk density in an actual furnace can be estimated with high accuracy from a small amount of sample, making it easy to adjust the amount of coke produced. The bulk density of furnaces with different furnace heights can also be estimated immediately by determining the bulk density corresponding to the pressure depending on the head difference.

Furthermore, the effects of factors such as the type of charged coal, moisture content, particle size, and presence or absence of oil addition on the bulk density can be easily grasped, and coke production can be adjusted based on this knowledge.

Furthermore, the measurement method of the present invention has the advantage that measurement is simple and quick, and can be operated by one person.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of an apparatus suitable for use in the measuring method of the present invention. FIG. 2 is a relationship diagram when the relationship between pressing force and bulk density is determined according to the method of the present invention. FIG. 3 is a relationship diagram when the bulk density was determined according to the method of the present invention when the amount of oil added and the moisture content were changed. FIG. 4 is a diagram showing the relationship between bulk densities determined according to the method of the present invention when the particle size of sample coal is changed. FIG. 5 is a relationship diagram showing the relationship between falling distance and bulk density in the ASTM method. (1) Load cell, (2) Sample container, (3
)... Piston, (4)... Lifting screw, (5)...
・Recorder Figure 1 Figure 2 Pressure force (g/crn') Figure 3 6 7 8 9 10 1+ Charged coal moisture (voice) Figure 4 - 3mm 9 degrees (%) Figure 5 Falling distance (m )

Claims (1)

[Claims] 1. Charge a coal sample into a cylindrical sample container, compress the sample in the container with a piston, measure the relationship between the pressurizing force and bulk density, and use that relationship to determine whether to charge the actual furnace. A method for measuring the bulk density of coal, which is characterized by determining the bulk density under a pressing force corresponding to the impact force at a time.