The Design And Research Of PLA Particles Equipment Based On High Pressure And Supercritical CO₂

This paper summarizes the current situation of technology of supercritical high-pressure carbon dioxide fluid, puts forward that how to reduce the diameter of PLA particles and improve the quality of PLA superfine particles have great significance in the pharmaceutical field, and the size and structure of the nozzle are the keys to solve the problem. The structural innovation design of nozzle through in-depth analysis and research will have practical value and significance in the pharmaceutical field.Through the analysis of the structure characteristics of atomization mechanism of the nozzle and the various forms of nozzle, a set of SEDS type nozzle is designed, the nozzle ejects material through two adjustable gaps, and its main parts, large and small nozzle body sleeve’s strength are calculated, its main structure dimensions were determined.By using the gas-liquid two-phase flow theory the flow characteristic of nozzle flow field are analyzed, the numerical simulation model of the nozzle flow field is established. By using FLUENT software the influence of different gaps, different pressure of CO2and different flow of organic solution on the nozzle flow field is analyzed. Based on the simulation results, the suitable working conditions of the nozzle are found, the whole numerical simulation process of nozzle provides a basis for the following experiments. According to the simulation results, through several groups of experiments and the particle size and scanning electron microscope analysis of PLA particles, the best working conditions of nozzle are found.