The influence of humidity, temperature and other variables on the electric charging characteristics of particulate aluminium hydroxide in gas–solid pipeline flows

This paper reports work undertaken to explore the influence of air relative humidity, temperature and particle size on the electric charging characteristics of particulate aluminium hydroxide during transport in a pneumatic pipeline. Limited data with regard to the influence of flow suspension density and velocity is also reported. Values of air relative humidity from 35% to 50% and temperatures of 19°C and 30°C are investigated, along with mean particle sizes ranging from 49 to 98 μm. Flow velocities between 16 and 36 m/s and suspension density values of 50 and 10 mg/m3 are also investigated. The presented data suggest that a reduction in temperature and an increase in relative humidity generally lead to a reduction in charge level. A peak in charge level is experienced for a particle size in the region of 80 μm.