Research on the evaluation method for uncertainty of intelligent coal sampling preparation and testing

MAO Guangjian; ZHANG Bo; ZHANG Qi

doi:10.3969/j.issn.1007-7677.2025.05.006

Abstract：The research on the evaluation method for measurement uncertainty of intelligent coal sampling,prepara-tion and testing based on the tests of mechanical sampling system which is benefit to reflect the quality of batch coal testing results more efficiently and accurately.Combining the whole process elements of coal mechanical sampling,offline preparation and analysis,as well as the characteristics of precision test and bias test for sampling and prepara-tion equipment,based on the precision test and bias test data of sampling and preparation equipment,and taking ash content detection for example,the research on the uncertainty evaluation of the whole process of mechanical or intelli-gent coal sampling,preparation and analysis is carried out.The sources of measurement uncertainty of ash content determination results in the whole process of intelligent coal sampling,preparation and analysis are analyzed.Based on the precision and bias test methods of sampling and preparation equipment,a method for evaluating the measure-ment uncertainty of ash content in the mechanical sampling and preparation stages is proposed,using the standard de-viation of the precision test and the maximum bias B'of the bias test.The measurement uncertainty of the ash content determination result is evaluated.The results show that the method based on standard deviation of precision test and maximum bias B'of bias test to evaluate the uncertainty of measurement in the whole process of coal sampling,preparation and testing is feasible and reliable.For coal with ash content of about 25％,the uncertainty caused by mechanical sampling is 0.376％,the uncertainty caused by off-line sampling is 0.219％,the uncertainty caused by testing is 0.071％,the combined uncertainty of the whole process is 0.441％and expanded uncertainty is 0.88％.In the whole process of intelligent coal sampling,preparation and testing,the uncertainty caused by mechanical sam-pling is the maximum,followed by off-line sample preparation,and the uncertainty introduced by testing is the mini-mum.There is similar level of uncertainty caused by the bias of mechanical sampling,the repeatability of mechanical sampling and the repeatability of off-line sample preparation.