A truly scientific method for coal acceptance
2023-10-11 16:42A truly scientific method for coal acceptance
The results were in strict conformity with the national standard repeatability, but the interval content was unstable.
Maximum reflectance Rran/% | Repeatability limit/% | Reproducibility limit/% | ||||
aa=0.02 | a=0.03 | a=0.04 | a=0.06 | a=0.10 | ||
≤1.00 | 0.03 | - | - | - | - | 0.09 |
＞1.00~1.90 | - | 0.04 | - | - | - | 0.10 |
＞1.90~2.40 | - | - | 0.06 | - | - | 0.15 |
＞2.40~3.50 | - | - | - | 0.08 | - | 0.20 |
≥3.50 | - | - | - | - | 0.14 | 0.35 |
a ：a is for accuracy. | ||||||
Permissible error of vitrinite random reflectance test results in national standards.
Coding | Partition index | Type | |
Reflectance standard deviation s | Notch number | ||
0 | s≤0.10 | 0 | Single seam coal |
1 | 0.10＜s＜0.20 | 0 | Simple undented coal mixture |
2 | s≥0.20 | 0 | Complex mixed coal without notch |
3 | s＞0.10 | 1 | Mixed coal with one notch |
4 | s＞0.10 | 2 | Mixed coal with two notches |
5 | s＞0.10 | ＞2 | Mixed coal with more than two notches |
Note: The reflectance distribution map with the characteristics of code 1, may also be a single seam coal of high rank bituminous coal and anthracite coal. | |||
Vitrinite reflectance distribution map of commercial coal, how to divide single mixed coal by national standard.
The methods of scientific acceptance of coal are as follows:
Method one:
The average value of Rran (marked with positive and negative errors) combined with the standard deviation S value is used for acceptance.
For example:Before purchasing a particular coal, sample it several times for testing. For example: The Rran average of the three averaging results is 0.52, standard deviation is 0.06.
The terms and conditions for signing the contract are as follows:The average Rran value of coal is 0.52±0.04, that is, between 0.48 and 0.56 are qualified, at the same time, the standard deviation S is required to be less than 0.08.This will not be due to the normal error of the detection of the coal supplier, but also to ensure the quality of their own raw materials into the factory.
Method two:
Cut acceptance method with some extension to both sides.
For example: Reflectance distribution of a coal sample, beginning with 1.5 and ending with 1.9. Then both parties sign the contract: Coal must ensure that the distribution map starts from 1.45 to 1.95, and the content in this interval is ≥93%.