JPH09279150A - Rapid heating of blended coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coke for a metallurgy excellent in quality by rapidly heating a blended coal at a specific condition set by measuring electron spin resonance spectra of the blended coal before and after the rapid heating. SOLUTION: This method for rapidly heating a blended coal comprises measuring electron spin resonance spectra of the blended coal containing a non slightly coking coal before and after the rapid heating, setting a temperature elevation rate and/or a heating temperature so as to attain >=1.2 relative value of spin concentrations in the electron spin resonance spectra of before the rapid heating to after the rapid heating and then rapidly heating the blended coal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid heating method for blended coal, which comprises rapidly heating and reforming blended coal containing non-caking coal and then carbonizing it in a chamber furnace type coke oven to produce metallurgical coke. Regarding

[0002]

2. Description of the Related Art A large amount of coal having a strong caking property (hereinafter referred to as caking coal) has been required as a raw material coal used for conventional coke production for a blast furnace.

In recent years, inexpensive non-fine coking coal has been used instead of expensive coking coal. For example, a method of significantly improving coke productivity and diversifying coking coal has been considered. The present inventors have added 25
After heating to 0 to 350 ° C., the pulverized coal portion of the non-caking coal is rapidly heated from the softening start temperature of the non-caking coal to the maximum flow temperature or less, and then the non-caking coal fine powder is heated. Japanese Patent Application No. 07-0. A method of performing hot forming, mixing with coking coal and the coarse coal portion of the non-fine coking coal, charging the mixture into a coke oven, and carrying out dry distillation.
Proposed in No. 15959. This process can increase the usage rate of non-caking coal to 50%, and is a process that can be applied to a large amount of non-caking coal. In such rapid heating of blended coal, when the rapid heating temperature is lower than the optimum temperature, the coal is not sufficiently reformed and the caking property is not improved, and when it is higher than the target temperature, it is charged into the carbonization chamber. Caking appears before being treated, which adversely affects coking in the carbonization chamber. In addition, the optimum rapid heating temperature at which the effect of improving caking is obtained differs depending on the type of coal or the blending ratio of the coal blend, and it is necessary to optimize the rapid heating conditions for each coal type or the blending ratio of the blend coal. is there.

In order to optimize the rapid heating conditions of coal, it is necessary to evaluate the caking property of the coal modified by rapid heating or to evaluate the coke strength by carbonizing the modified coal. is there.

As a typical test method for evaluating the caking property of coal, the plastometer method, the button method, etc. have been conventionally used.

The Gieseler plastometer method, which is a typical example of the plastometer method, is performed in the following procedure. First, a coal sample is loaded into a retort in which a stirring rod is set, and then heated in a metal bath at a prescribed heating rate. At this time, if a constant torque is applied to the stirring rod, the stirring rod rotates as the coal softens. It is a test method for measuring the softening start temperature, the maximum fluidity and the resolidification temperature by this rotation behavior.

The button method is also called a crucible expansion index,
A coal sample having a size of 250 μm or less is put in a predetermined crucible, and a coke button, which is a heating residue generated by heating, is compared with a standard contour to easily evaluate the caking property of coal. This method has the characteristic that the cohesiveness that governs the coke strength and the expansion rate can be evaluated simultaneously.

When the optimum heating conditions are evaluated by the coke strength, the coke is produced under the same carbonization conditions for coal pretreated under various heating conditions, the coke strength is obtained, and the heating conditions are evaluated.

[0009]

Among the coal quality evaluation methods that have been conventionally used, the non-slightly caking coal in the Giesela plastometer method has a low rotation speed and a low detection accuracy when it is targeted for non-caking coal. In addition, the caking coal that has been pretreated may not be able to be measured due to excessive flow.
The button method has poor quantitative properties and cannot be applied to non-slightly caking coal with a low expansion coefficient. Therefore, these methods cannot be used for evaluation of heating conditions.

Further, in the case of dry-distilling the reformed coal and evaluating the rapid heating condition from the coke strength, it is necessary to dry-distill under the same condition and compare the coke strength for each heating condition. I need.

It is an object of the present invention to provide a method capable of evaluating the reforming effect of rapid heating of coal by a simple method and easily obtaining optimum rapid heating conditions.

[0012]

Means for Solving the Problems In order to solve the above problems, the present invention is as follows: (1) When coal-containing coal containing non-caking coal is rapidly heated and reformed, coal-containing coal before and after rapid heating The electron spin resonance spectrum of is measured, and the heating rate and / or heating temperature for rapid heating are set so that the relative value of the spin concentration in the electron spin resonance spectrum of the blended coal after rapid heating is greater than or equal to the specified value. It is a rapid heating method for blended coal, which is characterized by rapidly heating.

(2) The rapid heating method for blended coal according to the item (1), wherein the predetermined value is 1.2.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The specific contents will be described below.

FIG. 1 is a diagram showing a coal rapid heating apparatus according to the present invention. 1 is a coal hopper, 2 is a hot air generator, 3 is an air flow heating tower, 4 is a cyclone, 5 is a heated coal hopper, and 6 is a coke oven for charging coal reformed using a rapid coal heating device.

The inventors of the present invention measured the ESR (electron spin resonance) spectrum of blended coal containing non-fine coking coal rapidly heated to each temperature and investigated the spin concentration. As a result, rapid heating of blended coal It was found that the spin concentration changed, and it was found that the spin concentration can be used to evaluate the reforming effect of rapid heating of blended coal. Therefore, as a result of further detailed investigation on the relationship between the relative value of the spin concentration after the rapid heating and the coke strength before the rapid heating, the relative value of the spin concentration is also constant under the rapid heating condition in which the coke strength is improved. It became clear that the value was equal to or more than the value, and it was found that the rapid heating conditions such as the rapid heating temperature or the heating rate can be optimized based on the relative value of the spin concentration, and the present invention was completed.

The spin concentration in the present invention means the average value "(A + B) / 2" of the intensity of the first derivative of the microwave absorption curve as shown in FIG. 2 obtained from the ESR measuring device and the width between peaks. “H × (A + B)”, which is the product of “H”
/ 2 ". The spin concentration correlates with the concentration of free radicals in coal. It is related to the factors that develop connectivity.

The inventors of the present invention reformed the blended coal of various blended coals shown in Table 1 under rapid heating conditions in which the gas temperature and the gas flow rate were changed, and measured the ESR spectra of the coals before and after rapid heating. Then, the relative value of the spin concentration after the rapid heating is calculated with respect to that before the rapid heating, and the blended coal after the rapid heating is further carbonized to obtain the coke strength (JIS 21
As a result of investigating the relationship with the drum strength (DI ¹⁵⁰ ₁₅ ) shown in 51, as shown in FIG. 3, if the relative value of the spin concentration was 1.2 or more, the coke strength after carbonization was 80.
It turned out to exceed. The time required for measuring these spin concentrations is only a few minutes per sample, and the measurement procedure is very simple. In this way, by determining whether or not the relative value of the spin concentration exceeds a certain value, the rapid heating condition can be easily evaluated, and the optimum heating condition can be obtained.

[0019]

[Table 1]

[0020]

EXAMPLES The effects of the present invention will be described below with reference to examples.

(Example 1) In order to determine the optimum rapid heating conditions for blended coal containing non-slightly caking coal shown in Table 2, reforming of coal under 5 levels of rapid heating conditions as shown in Table 3 And then
The spin concentration before and after the rapid heating was measured, and the relative value of the spin concentration after the rapid heating was calculated relative to that before the rapid heating. An electron spin resonance device JES FE3X manufactured by JEOL Ltd. was used for ESR measurement for measuring the spin concentration. Central magnetic field
3370 GAUSS, magnetic field sweep width ± 50 GAUSS, magnetic field modulation width 0.6
The ESR spectrum was measured under the measurement conditions of 8 GAUSS to determine the spin concentration.

As a result, as shown in Table 3, the three levels of B, C and D have a relative spin concentration of 1.2 or more, and the two levels of A and E have a relative spin concentration of less than 1.2. And FIG.
From the relationship between the relative value of the spin concentration and the coke strength of B,
It can be judged that the rapid heating conditions of C and D are suitable, but the rapid heating conditions of A and E are not suitable.

After rapid heating under the conditions of 5 levels A to E, coking was conducted under the same dry distillation conditions to measure the coke strength. As shown in Table 3, B, C. Three levels of D showed high coke strength, and two levels of A and E showed low coke strength. From these results, it was confirmed that the rapid heating condition of the blended coal can be optimized based on the relative value of the spin concentration.

As described above, in the past, in order to optimize the rapid heating conditions, the blended coal rapidly heated for each level of the rapid heating conditions was carbonized in a coke oven to obtain the coke strength. The invention has made it possible to optimize the rapid heating conditions simply, quickly and accurately.

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

INDUSTRIAL APPLICABILITY As described above, the present invention relates to a method for easily and accurately evaluating the rapid heating conditions of blended coal that has been subjected to rapid heating treatment, which leads to a reduction in coke production cost. The economic and economic effects are very large.

[Brief description of drawings]

FIG. 1 is a diagram showing a coal rapid heating device.

FIG. 2 is a diagram schematically showing an ESR spectrum obtained by an ESR measuring device.

FIG. 3 is a diagram showing a relationship between spin concentration and coke strength.

[Explanation of symbols]

 1: Coal hopper 2: Hot air generator 3: Air flow heating tower 4: Cyclone 5: Heating coal hopper 6: Coal rapid heating device

Claims (2)

[Claims] 1. When the coal blend containing non-slightly caking coal is rapidly heated and reformed, the electron spin resonance spectra of the coal blend before and after the rapid heating are measured, and the coal blend after the rapid heating before and after the rapid heating. A rapid heating method for blended coal, characterized in that a rapid heating rate is set and / or a heating temperature is set so that the relative value of the spin concentration of the electron spin resonance spectrum is equal to or higher than a predetermined value. 2. The rapid heating method for blended coal according to claim 1, wherein the predetermined value is 1.2.