JPH02263143A - Method of measuring volatile matter of coal - Google Patents

Abstract

PURPOSE:To easily, rapidly and accurately measure the volatile matter of coal by charging a specified amt. of pulverized coal subjected to a preliminary drying treatment into a heat resistant glass container and heating the coal after weighing, then weighing the coal again to determine the weight decrease by heating and determining the volatile matter value converted to a JIS method from the value of this weight decrease by heating. CONSTITUTION:The specified amt. of the raw material pulverized coal for coke subjected to the preliminary drying treatment is charged to into the heat resistant glass container and is weighed; thereafter, the coal is heated for >=5 minutes at 500 to 750 deg.C. The coal is weighed again after the heating and the weight decrease by heating is determined. The volatile matter value converted to the JIS method is then determined by using the relation between the value of the weight decrease by heating, the predetermined value of the weight decrease by heating at a prescribed temp. and the volatile matter measured by this JIS method. The volatile matter of the coal which is an important index to evaluate the quality of the raw materials for producing the coke is easily, rapidly and accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for simply, quickly and accurately measuring the volatile content of coal, which is one of the important indicators for quality evaluation of raw material coal for coke production.

BACKGROUND OF THE INVENTION One of the important issues facing the coke manufacturing industry in recent years is to simultaneously achieve stable quality and efficient coke oven operation. For this reason, progress has been made in promoting automation of combustion management for the purpose of uniform carbonization of coke and reducing the amount of heat of carbonization, and in speeding up and stabilizing the quality adjustment of coal charged in coke ovens by automating the property analysis of coal and coke. There is.

The method for quantifying volatile content, which is one of the important indicators for quality evaluation of coking coal for coke production, is JIS) 188.
There are industrial analytical methods specified in 12.

In this method, sample 13 is placed in a crucible with a lid, heated at a temperature of 900'C for 7 minutes while avoiding contact with air, and the percentage loss on heating relative to the mass of the sample is determined, which is then simultaneously quantified. This method reduces the moisture content and converts it into volatile matter.

In addition to this, various industrial analysis methods using thermobalances have also been attempted. For example, Martin Ottawa
y; Fuel, 61. p713-716198
2), John, P. Elder
; [uel, 62. p580-584゜198
3), Lines et al. (Analytical Chemistry; 34. 5. 51-54
1985), Japanese Patent Application Laid-open No. 19150/1983, etc.

Although these methods differ slightly in temperature raising time, holding time, etc., they are basically carried out according to the following procedure.

After weighing a sample of several m3 to several tens of IrIg into a container and setting it on a thermobalance, it is held at a temperature of 100 to 110°C for a predetermined time in a nitrogen atmosphere, and the percentage of the heated raw material with respect to the sample mass at this time is determined to determine the moisture content. shall be. Similarly under nitrogen atmosphere, 90
The temperature is rapidly raised to 0 to 950'C, maintained at this temperature for a predetermined period of time, and the percentage loss on heating relative to the mass of the sample is determined to determine the volatile content. Next, the atmosphere is changed to oxygen or air, and the temperature is maintained at 900° C. or 815° C. until constant weight is reached, and the weight percentage of the residual component at constant weight with respect to the mass of the sample is determined to be the ash content.

However, the above-mentioned JIS method has one drawback: it takes a long time to measure, is difficult to automate, and provides insufficient feedback for quality adjustment. Furthermore, in the method using a thermobalance, the amount of sample is small, and in the case of a heterogeneous material such as coal, there is a risk that the sampling error will increase, and it is currently difficult to fully automate the sampling process.

[Problems to be Solved by the Invention] - As mentioned above, the volatile content of coal for lath manufacturing is measured according to the JIS method and used for estimating the amount of tar and gas generated and adjusting the quality of coal charged in a coke oven. However, measurement takes time and is difficult to automate, and feedback for quality adjustment is insufficient.Also, the method using a thermobalance has problems with measurement accuracy and is difficult to automate.

The present invention aims to solve these problems of the prior art and propose a method that can simplify, speed up, and automate the measurement of volatile content in coal.

Means to Solve the Problem The volatile content of coal indicates the amount of components other than water that escape from the coal during the carbonization process. According to the results of investigating the generation of pyrolysis gas during the carbonization of coal, the volatile components are mainly tar, CO1CD2, H2, and lower hydrocarbons, and although the maximum temperature of each generation differs depending on the type of coal. , lower hydrocarbons: 300-500℃
, Co, CO2 is 400-50°C, tar is 500°C.
~750°C and H2 exist at around 700°C, and most of the gas generation ends at approximately 900°C.

Therefore, the value corresponding to the volatile content used as an indicator in the coke industry needs to be measured at a temperature at least at which most of the H2 generation ends.

However, as a result of the inventor's studies, by determining the heating loss at a temperature below 900°C, at least at a temperature of about 500°C or higher where tar generation and decomposition of the main polymer part begin,
It has been found that the ratio between the amount of pyrolysis gas generated from that temperature to 900° C. and the amount of residual carbon at that temperature is almost constant regardless of the type of coal.

That is, in this invention, after charging and weighing a certain amount of pulverized coal that has been dried in advance in a heat-resistant glass container,
Heating at a temperature of 0°C for at least 5 minutes, after heating, weighing again to determine the heating loss, and the relationship between this heating loss value, the heating loss value at a predetermined temperature determined in advance, and the volatile content measured by the JIS method. The gist of this method is to obtain the volatile content value converted to the JIS method using the formula.

Any type of heat-resistant glass container can be used as long as it can be used at a temperature of 750°C, such as hard glass or quartz glass. Also, it is ugly to use metal.
“As a method of heating the coal, it is possible to use an annular electric furnace or a metal bath heated to a predetermined temperature, and it is also possible to use an infrared image furnace, a microwave heating furnace, etc.

The heating temperature of coal is limited to 500 to 750°C because the temperature at which tar generation and the decomposition of the polymeric part of coal begin is approximately 500'C, and when the temperature exceeds 750°C, the heating rate is reduced to 250°C/min. This is because the amount of volatile matter generated per unit time becomes too large, causing bumping of the sample and making it impossible to obtain a reproducible heating loss value.

Further, after reaching this temperature, a stable value can be obtained by holding the temperature for 5 minutes or more, so the heating holding time was set to 5 minutes or more.

When the heating loss value is calculated, the volatile content converted to the JIS method volatile content is determined by the relational expression between the heating loss value at a predetermined temperature shown in the following formula (1) calculated in advance and the volatile content measured by the JIS method. Calculate.

VMJ Is = (1-At) VMt +100
At...(1) VMJ Is: Volatile content (%) converted to JIS method volatile content VMt: Heating loss value (%) determined at temperature t'C by the method of this invention At: Conversion at temperature t'C Coefficient Figure 1 shows the ratio of the difference between the heating loss value at each temperature determined by the method of this invention and the JIS method volatile content value to the residual content at each temperature using the coal shown in Table 1. In Although,
It shows a nearly constant value between 500 and 750'C regardless of the coal type. Therefore, by determining this relationship in advance, JI
The S method volatile content can be easily determined.

Although the absolute value of the relationship shown in FIG. 1 changes as the temperature increase rate changes, the ratio remains constant and is not particularly influenced by the temperature increase rate.

Examples Example 1 Using the coal shown in Table 1, it was dried for 30 minutes in a rotating drum dryer heated to 60'C, coarsely ground in a double roll mill, and finely ground to 250 μm or less in a vibrating disc mill. The pulverized coal obtained by drying it in a dryer at 107°C ± 10°C for 1 hour was placed in a heat-resistant glass tube with an inner diameter of 10m and a length of 120mm at a height of 20mm. , using a stainless steel holding container in a metal bath with a capacitance of IKW, packed with a charging density of o, "tg4, and set at a temperature of 550 °C.
#, heated at a heating rate of 100°Q/min, taken out after 10 minutes, cooled to room temperature, weighed, and converted to JIS volatile content using the relationship in Figure 1. I asked for a minute.

The relationship between the volatile content determined by this calculation and the JIS method volatile content is shown in FIG.

As is clear from FIG. 2, the average reflectance is 0.68 to 1.
Despite the 22 coals having different carbonization degrees over a wide range, the difference from the JIS method volatile content was within 1.3% in terms of standard deviation, showing good agreement.

Example 2 Table 2 shows the results of determining the volatile content of two types of coal blends used as raw materials for coke production in the same manner as in Example 1.

As is clear from Table 2, the method of the present invention was able to easily obtain values equivalent to the JIS method for blended coal as well as for single coal.

Example 3 B, V, Blend charcoal (JIS method volatile content value 26.2%)
Using the same method as in Example 1 (however, only the heating method used an infrared image furnace with a capacitance of 1 and Δ), the heating loss value was determined by changing the heating temperature and the heating time after reaching that temperature. Table 3 shows the results of determining the volatile content converted to the JIS method volatile content using the relationship shown in FIG.

Table 3 shows that when the heating temperature exceeds 750°C, bumping of the sample tends to occur, making it difficult to obtain accurate measurement values, and even when the heating time is less than 5 minutes, accurate measurement values cannot be obtained. On the other hand, it is clear that highly accurate measured values can be obtained at a heating temperature of 500 to 750'C1 and a heating time of 5 minutes or more.

Margin table below (%) Table (%) As explained in detail, according to the method of this invention, the volatile content of coal, which is an important index for quality evaluation of raw materials for coke production, can be easily and quickly measured. Since it can be measured well and is easy to automate, it provides sufficient feedback for quality adjustment and greatly contributes to stabilizing coke quality.

[Brief explanation of drawings]

Figure 1 is a diagram showing the ratio of the difference between the heating loss value at each temperature determined by the method of this invention and the volatile content measured by the JIS method to the residual content at each temperature, and Figure 2 is a diagram showing the ratio of the difference between the heating loss value at each temperature determined by the method of this invention and the residual content at each temperature. It is a figure which shows the relationship between the calculated volatile content and the volatile content measured by JIS method in an example. Applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] After charging a certain amount of pulverized coal that has been dried in advance into a heat-resistant glass container and weighing it, heat it at a temperature of 500 to 750°C for at least 5 minutes, and after heating, weigh it again to determine the loss on heating. A method for measuring the volatile content of coal, characterized in that the volatile content value converted to the JIS method is determined using a relational expression between the value, the heating loss value at a predetermined temperature determined in advance, and the volatile content measured by the JIS method.