Production and tuning of spherical agglomerates of benzoic acid using membrane dispersion systems

Two membrane systems were proposed as novel spherical agglomeration techniques. The first system uses a flat static membrane, with different pore sizes and different pore configurations, while the second system is based on an oscillating cylindrical membrane. The main objective is to enhance the control of the bridging liquid droplet size and generate a large density of monodisperse droplets, which in turn allows better control and tuning of the properties of the spherical agglomerates. Spherical agglomerates of benzoic acid were obtained under different conditions, namely the agitation rate, the bridging liquid flow rates and total addition time, and membrane properties. Spherical agglomeration was successfully achieved using the proposed membrane configuration and operating conditions. It was shown that the flat membranes, particularly the ring membrane, provide enhanced control over the bridging liquid droplet size which resulted in a more effective control of the size, morphology, and micrometric properties of the spherical agglomerates. Most importantly, with the proposed systems it was possible to significantly reduce the bridging liquid to solid ratio (BLSR) down to 0.3-0.7 mL/g compared to the values commonly reported in the standard procedure (i.e., 0.59 to 1.25 mL/g).