Research of the lower explosion limit of coal dust based on the statistical method of Logistic regression

The lower explosion limit of dust cloud is a basic characterization of the dangers of inflammable and explosive dust. Accurately test and show the lower explosion limit is important for the assessment and prevention of dust explosion disaster. According to Logistic regression model based on statistical analysis, using the calculation method of the lower explosion limit of dust cloud which represented by probability, the experiments on the lower explosion limit of coal dust with different diameters were conducted in 20 L spherical explosion test apparatus. The test results were analyzed using statistical software (SPSS) to obtain probability distributions for ignition versus dust concentrations of coal dust with different diameters and different experimental frequency. The results show that the lower explosion limit of coal dust under different ignition probability has a tendency to decrease with reducing particle size. And the smaller the particle size, the narrower the range of concentration of ignition probability from 10% to 90%, which means the deflagrating characteristic of coal dust is becoming much more stable. The lower explosive limit probability distribution is affected by experimental frequency, the more the experiments, the narrower the range of lower explosive limit concentration. When the ignition probability is 50%, the corresponding concentration has nothing to do with the number of experiments, which is the key to the research of dust explosion experiment. Compared with other standard calculations, the viewpoint of ignition as a statistical phenomenon appears to be more consistent with the test data in engineering, can also meet the needs of different production environment for security control.