Parallelized microfluidic droplet generators with improved ladder–tree distributors for production of monodisperse γ-Al2O3 microspheres

In this paper, we present a parallelized microfluidic device with improved ladder–tree distributors for the scaled-up production of monodisperse microspheres. Owing to the improved distribution form comprising a ladder distributor in the center and tree distributors around the circumference, the uniformity of the generated droplets for our device was improved by 32.9% and 86.1% compared to those achieved in devices with conventional tree and ladder distributors, respectively, in the final production stage with 32 droplet generators, indicating the potential of our device for further scale-up while maintaining the monodispersity of the generated droplets. The effect of the 2D scale-up of our device was investigated by varying the continuous-phase flow rate and viscosity. Using our device, γ-Al 2 O 3 microspheres with a diameter of 598.1 μm and a CV of 2.58%, as catalyst support for microreactors, were continuously synthesized at high production rate. The nickel-based catalyst prepared from γ-Al 2 O 3 microspheres with large specific surface area and pore volume had an average NiO size of 14 nm, which was 60.9% of that supported on industrial support. The CO methanation conversion of the Ni@Al 2 O 3 microspheres was 1.7 times larger than Ni@Al 2 O 3 industrial support at 140 °C.