Study on the influence mechanism of humidity on coal mine dust concentration monitoring and its compensation

Online monitoring of dust concentration is a critical foundation for coal mine safety monitoring and pneumoconiosis early warning, with monitoring error being a core indicator that determines the reliability of the technology. To further reduce the error in dust concentration online monitoring, this study proposes a humidity compensation technique based on multi-angle light scattering. Through experiments observing the hygroscopic growth and morphological characteristics of coal dust particles, the study reveals the particle size variation under different humidity conditions and the impact mechanism of humidity on dust concentration monitoring. Based on this, the Mie scattering theory is analyzed, and the principles of multi-angle light scattering are studied to establish a real-time humidity compensation mathematical model for dust concentration monitoring. Subsequently, a multi-angle light scattering dust concentration monitoring unit is developed, and the relationships between environmental humidity, dust particle size, and scattering light flux are systematically studied. A humidity compensation experimental model is built, and a multi-angle light scattering humidity compensation dust concentration monitoring technology based on this model is proposed. By embedding the humidity compensation experimental model into the monitoring unit and conducting comparative tests, the results show that the monitoring error of the multi-angle light scattering dust concentration monitoring unit with humidity compensation is ≤11.2%, which is 2.9% lower than that of the monitoring unit without humidity compensation.