Detection method for reducing caking index measurement error of bituminous coal

Abstract

The invention discloses a detection method for reducing a caking index measurement error of bituminous coal. The detection method is characterized by comprising the following steps: 1) weighing a sample; 2) stirring the sample; 3) pressurizing the sample; 4) burning and cooling the sample; and (5) rotating the sample into a drum, screening, weighing and calculating. The invention aims to provide the detection method for reducing the caking index measurement error of the bituminous coal, and in the measurement process, a mode of supplementing manual stirring and uniform mixing with mechanical automatic stirring is adopted, so that a more accurate and reliable measurement value is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of coal char detection, and in particular relates to a detection method for reducing the measurement error of the caking index of bituminous coal. Background Art

[0002] At present, the determination of the cohesive index of bituminous coal is mostly based on the national recommended standard GB / T 5447, which stipulates that the mixture in the crucible is stirred for 2 minutes with a stirring wire. The stirring method is: the crucible is tilted about 45", rotated counterclockwise, with a speed of about 15r / min, and the stirring wire is rotated clockwise at the same inclination angle, with a speed of about 150r / min. During stirring, the ring of the stirring wire contacts the arc part connecting the crucible wall and the bottom. After about 1'45", while continuing to stir, the crucible and the stirring wire are gradually turned to a vertical position. After about 2 minutes, the stirring is completed. During the stirring process, the coal sample should be prevented from splashing. Note: A mechanical device that achieves the same stirring effect can also be used. After stirring, the coal powder on the crucible wall is gently swept down with a brush, and the mixture is carefully leveled with a stirring wire, and the layer along the crucible wall is slightly lower by 1mm to 2mm, so that after the mixture is pressed by the pressing block, the surface of the coal sample is at the same level.

[0003] In actual operation, manual stirring is restricted by human factors and has a large reproducibility error. When mechanical automatic stirring is used completely, since the radius of the stirring wire is fixed, a collapse circle with this radius as the circle will appear after stirring, causing the coal sample with high surroundings to stick to the crucible wall and become stratified. At the same time, in a hot and humid weather environment, small aggregated balls of coal samples will appear after mechanical stirring. If they are not crushed manually, the results will be biased low.

[0004] In view of this, the invention of this method is particularly important. The invention provides a more accurate determination method for the determination of the bituminous coal caking index, and the invention method adopts a mechanical automatic stirring method to supplement the manual stirring and mixing during the determination process, so as to obtain a more accurate and reliable determination value. Summary of the invention

[0005] In order to overcome the large error caused by uneven stirring in the determination of the adhesion index of bituminous coal, the purpose of the present invention is to provide a detection method for reducing the error in the determination of the adhesion index of bituminous coal, thereby reducing the reproducibility difference caused by manual stirring during operation and the systematic error caused by single mechanical automatic stirring.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a detection method for reducing the error in measuring the caking index of bituminous coal, comprising the following steps:

[0008] 1) Sample weighing: first weigh an appropriate amount of standard anthracite, then weigh an appropriate amount of test bituminous coal and put them into the crucible;

[0009] 2) Sample stirring: After automatic stirring with a mechanical stirring device, remove the crucible and stir manually with a stirring wire for 10s±2s. Use the stirring wire to gently scrape the coal powder on the crucible wall to crush the small coal particles that are gathered, and level the coal sample, with the layer along the crucible wall being 1mm-2mm lower;

[0010] 3) Sample pressurization: Use tweezers to pick up a block in the center of the crucible, and then place it under the press for 25-35 seconds. After the pressurization is completed, the block remains on the mixture and the crucible cover is added;

[0011] 4) Sample burning and cooling: Place the covered crucible in the crucible stand, lift the crucible stand with a flat shovel with a handle, and place it in the constant temperature zone of a muffle furnace preheated to 850±10℃. After coking for 14-16 minutes, take the crucible out of the muffle furnace and let it cool to room temperature.

[0012] 5) Sample drumming, screening, weighing and calculation: Take out the pressed block from the cooled crucible; when there are coke crucibles attached to the pressed block, brush them into the crucible, weigh the total mass of the coke residue, and then carry out the first drum test. The coke block after the drum test is sieved with a 1mm round hole sieve, weigh the mass of the part on the sieve, and then carry out the second drum test, screening, weighing and calculate the results.

[0013] Furthermore, in the step 3), the mixture is placed under pressure for 30 seconds.

[0014] Furthermore, in the step 4), the crucible is placed in a constant temperature zone of a muffle furnace preheated to 850° C., and after coking for 15 minutes, the crucible is taken out of the muffle furnace and allowed to cool to room temperature.

[0015] Furthermore, in the step 1), the standard anthracite is weighed at 5 g and the test bituminous coal is weighed at 1 g, accurate to 0.001 g.

[0016] Furthermore, in the mechanical stirring device in step 2), the crucible is tilted at an angle of 45° and rotates counterclockwise at 15 r / min, and the stirring wire is tilted at an angle of 45° and rotates clockwise at a speed of about 150 r / min. During stirring, the circular ring of the stirring wire contacts the crucible wall and the connected circular part. After 1 min 45 s, while continuing to stir, the crucible and the stirring wire are gradually turned to a vertical position. After 2 min, the automatic stirring ends.

[0017] Furthermore, in step 3), the pressure block is made of nickel-chromium steel and has a mass of 110g-115g.

[0018] Furthermore, within 6 minutes after the crucible is placed in step 4), the furnace temperature should be restored to 850°C, and thereafter the furnace temperature should be maintained at 850°C±10°C.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are:

[0020] The methods for determining the caking index of bituminous coal in the national recommended standards and other literatures either use a purely manual stirring method for samples or a purely mechanical device to automatically stir samples. Both stirring methods have certain disadvantages. The method of purely manual stirring of samples results in large fluctuations and poor reproducibility. The method of purely mechanical device to automatically stir samples results in smaller fluctuations, but is prone to uneven stirring or obvious aggregation and agglomeration, resulting in systematically low results.

[0021] The present invention can reduce the measurement error caused by uneven manual stirring, and prevent the measurement result from being systematically low under certain conditions due to mechanical automatic stirring, thereby making the measurement result more accurate, more stable and more reproducible. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with examples to enable those skilled in the art to further understand the present invention, but does not constitute a limitation of the present invention.

[0023] Embodiment 1:

[0024] A detection method for reducing the error in measuring the caking index of bituminous coal, the specific operation is as follows:

[0025] Sample weighing: Weigh 5 portions of 5.000g of standard anthracite and put them into a crucible, and then weigh 5 portions of 1.000g of the bituminous coal standard sample numbered SDRM040003 and put them into the above crucible.

[0026] Sample stirring: After using the machine stirring device to stir automatically for 2 minutes, remove the crucible and stir manually with a stirring wire for 10 seconds. Use the stirring wire to gently scrape the coal powder on the crucible wall to crush the small coal particles that are gathered together, and level the coal sample, leaving a layer slightly lower than the crucible wall by 1mm-2mm.

[0027] Sample pressurization: Use tweezers to pick up a nickel-chromium steel block with a mass of 114g and place it in the center of the crucible so that the surface of the coal sample in the crucible is at the same level. Then place it under the pressurizer for 30s. After the pressurization is completed, the block remains on the mixture and the crucible cover is added.

[0028] Sample burning and cooling: Place the covered crucible in the crucible stand, lift the crucible stand with a flat shovel with a handle, and place it in the constant temperature zone of the muffle furnace that has been preheated to 850°C. 5 minutes after the crucible is placed, the furnace temperature returns to 850°C, and the furnace temperature is kept at 850°C. Start timing from the time the crucible is placed in the crucible. After 15 minutes of coking, take the crucible out of the muffle furnace and let it cool to room temperature.

[0029] Sample drum, sieving, weighing, and calculation: Take out the pressed block from the cooled crucible. If there is coke residue attached to the pressed block, it should be brushed into the crucible, and the total mass of the coke residue should be weighed. Then, it should be placed in the drum for the first drum test. The coke block after the drum test should be sieved with a 1mm round hole sieve, and the mass of the part on the sieve should be weighed. Then, it should be placed in the drum for the second drum test, sieving, weighing, and calculation of the results.

[0030] The measurement results are shown in the following table:

[0031]

[0032]

[0033] It can be seen from the data that the RSD% value of the result measured by the present invention is the smallest, and the measurement result is better than the measurement results of the other two stirring methods, the data is more accurate, and the precision is better.

[0034] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A detection method for reducing the error in measuring the caking index of bituminous coal, characterized in that: The following steps are involved: 1) Sample weighing: first weigh an appropriate amount of standard anthracite, then weigh an appropriate amount of test bituminous coal and put them into the crucible; 2) Sample stirring: After automatic stirring with a mechanical stirring device, remove the crucible and stir manually with a stirring wire for 10s±2s. Use the stirring wire to gently scrape the coal powder on the crucible wall to crush the small coal particles that are gathered, and level the coal sample, with the layer along the crucible wall being 1mm-2mm lower; 3) Sample pressurization: Use tweezers to pick up a block in the center of the crucible, and then place it under the press for 25-35 seconds. After the pressurization is completed, the block remains on the mixture and the crucible cover is added; 4) Sample burning and cooling: Place the covered crucible in the crucible stand, lift the crucible stand with a flat shovel with a handle, and place it in the constant temperature zone of a muffle furnace preheated to 850±10℃. After coking for 14-16 minutes, take the crucible out of the muffle furnace and let it cool to room temperature. 5) Sample drumming, screening, weighing and calculation: Take out the pressed block from the cooled crucible; when there are coke crucibles attached to the pressed block, brush them into the crucible, weigh the total mass of the coke residue, and then carry out the first drum test. The coke block after the drum test is sieved with a 1mm round hole sieve, weigh the mass of the part on the sieve, and then carry out the second drum test, screening, weighing and calculate the results.

2. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: In the step 3), the mixture is placed under pressure for 30 seconds.

3. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: In the step 4), the crucible is placed in a constant temperature zone of a muffle furnace preheated to 850° C. After coking for 15 minutes, the crucible is taken out of the muffle furnace and allowed to cool to room temperature.

4. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: In the step 1), the standard anthracite is weighed at 5 g, and the test bituminous coal is weighed at 1 g, accurate to 0.001 g.

5. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: In the step 2), the mechanical stirring device has a crucible tilt angle of 45°, rotates counterclockwise at 15 r / min, and a stirring wire tilt angle of 45°, rotates clockwise at a speed of about 150 r / min. During stirring, the circular ring of the stirring wire contacts the crucible wall and the connected circular part. After 1 min 45 s, the crucible and the stirring wire are gradually turned to a vertical position while continuing to stir. After 2 min, the automatic stirring ends.

6. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: The pressure block in step 3) is made of nickel-chromium steel and has a mass of 110g-115g.

7. The detection method for reducing the measurement error of the caking index of bituminous coal according to claim 1, characterized in that: Within 6 minutes after the crucible is placed in step 4), the furnace temperature should be restored to 850°C, and thereafter the furnace temperature should be maintained at 850°C±10°C.

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