Analysis of the effect of coal mine operating parameters on multi-slit virtual impact separator

Respirable dust is a major factor in coal workers’ pneumoconiosis. To effectively separate respirable dust from total dust for detection, this work designed a multi-slit virtual impactor based on sheath flow technology for respirable dust separation. Using response surface methodology, the flow parameters of the separator were optimized. Separation efficiency was calculated, an accurate control scheme for the operating parameters of the separator was derived. The results showed that the maximum error between experimental results and BMRC standard of the separation efficiency was 4.98 %. With an increase in sheath-flow ratio, the separation efficiency of separator decreases. As minor-flow ratio increases, the fit between efficiency curves and BMRC standard decreases, then increases. When sampling flow speed increases, the separation efficiency curves show a declining trend. The flow control scheme was determined: sheath-flow ratio is 111.41 %, minor-flow ratio is 10.68 %, and sampling flow speed is 3.45 m/s. The effect of temperature and humidity of the environment on the separation performance was generalized and enhanced the device environmental adaptability. The time span required for cleaning of separator over 18 days was extended by more than 100 %. This study saves cleanup costs and provides support for optimizing the performance of respirable dust separators.