A model for precipitation of sub-micrometric particles of PHBV poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by supercritical assisted-atomization

• A detailed model to describe the SAS process of precipitation of PHBV was suggested.
• It applies a MSMPR crystallizer model to represent the kinetics of particle formation.
• It uses the standard k − ɛ approach to model the turbulence and a CFD code to simulate.
• It reproduces experimental results of PHBV size distribution at different conditions.
• It is a valid procedure to design and optimize micronization based on the SAS technique.

A detailed model to describe the precipitation of PHBV microparticles with supercritical antisolvent at 313 K and 80 bar is presented. It considers the hydrodynamics of the jet, the kinetics of particles formation, the effect of turbulence on momentum transfer, conservation of mass and energy. A population balance model with parameters tuned on experimental results from the literature was used to calculate the nucleation and growth rates of PHBV microparticles. All the transport and physical properties were estimated with models for pure compounds at high pressure, and mixing rules. A fluid dynamic code was used to solve the system of algebraic partial differential equations that represent the process. The model was able to reproduce the experimental particle diameters distribution at different PHBV concentrations. The influence of the mass ratio of fed antisolvent to the organic solvent solution on diameters of produced PHBV microparticles was described correctly by the model.

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