Solid physical properties are vital for the design

optimization

and scale-up of gas–liquid–solid multiphase reactors. The complex and interactional effects of the solid physical properties

including particle diameter

density

wettability

and sphericity

on the hydrodynamic behaviors in a new external airlift loop reactor (EALR) integrating mixing and separation are decoupled in this work. Two semi-empirical equations are proposed and validated to predict the overall gas holdup and liquid circulating velocity satisfactorily

and then the individual influence of such solid physical properties is further investigated. The results demonstrate that both the overall gas holdup in the riser and the liquid circulating velocity in the downcomer increase with the contact angle

but decrease with particle size

density

and sphericity. Additionally

the impact of the particle size on the liquid circulating velocity is also profoundly revealed on a micro-level considering the particle size distribution. Moreover

the axial solid concentration distribution is discussed

and the uniformity of the slurry is described by the mixing index of the solid particles. The results show that a more homogeneous mixture can be achieved by adding finer particles other than attaining violent turbulence. Therefore

this work lays a foundation for the design

scale-up

and industrialization of the EALRs.