Study on the Industrial Production of Organic Fine Powders Using Supercritical Carbon Dioxide

超临界二氧化碳工业化生产有机细粉的研究

• 批准号: 15560654
• 负责人: TAKISHIMA Shigeki
• 金额: $ 2.43万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560654/
• 关键词: Supercritical Fluid; Polymer; Fine Powder; PGSS Method; 微粒子化; スプレー; 状態方程式

Conventional processes for micronization of polymers have several disadvantages. Recently, PGSS (Particles from Gas Saturated Solutions) process that uses supercritical fluids (SCF) attracts much attention as a solution of the disadvantages. SCF is dissolved in a molten polymer and the high-pressure mixture is rapidly depressurized through a nozzle. By cooling effect in course of expansion the polymer is solidified leading to particle formation by precipitation. Since PGSS process do not require the dissolution of polymers in SCF phase, this process can be applied to wide range of polymers and the application is investigated to pharmaceuticals, catalysts, paints, biopolymers, and foods. However, researches of this process are scare for polymers and mechanism of micronization and effect of process parameters are not known enough.The objective of the present work is to investigate the effect of initial temperature, pressure, SCF concentration and nozzle structure on the average particle … More size, particle size distribution and shape of resulting particles. Experiments were carried out for poly (ethylene glycol) (PEG) and polyester with supercritical carbon dioxide. As the results, fine particles of PEG with average molecular weight of 4000 could be obtained quickly at temperatures higher than 313 K, pressures higher than 10 MPa and CO_2 concentrations higher than 70 wt%. The average diameter decreased with decreasing temperature, increasing pressure, and increasing CO_2 concentration. By simulating the path of temperature and pressure during the decompression based on the energy balance, it was found that the period when the polymer is in liquid state decreased with decreasing temperature, decreasing pressure and increasing CO_2 concentration, and therefore the average diameter decreased and the shape changed to non-sphere. However, the effect of pressure in this simulation was opposite to the experimental results and the reason for this was considered to the change in the velocity of the mixture in the nozzle. Less

聚合物微粉化的传统工艺有几个缺点。近年来，采用超临界流体(SCF)的PGSS(气态饱和溶液中的颗粒)工艺作为一种解决这一问题的方法备受关注。超临界流体被溶解在熔融的聚合物中，高压混合物通过喷嘴快速降压。由于膨胀过程中的冷却作用，聚合物被固化，从而通过沉淀形成颗粒。由于PGSS工艺不需要聚合物在超临界流体中溶解，因此该工艺可以应用于广泛的聚合物，并被研究在制药、催化剂、涂料、生物聚合物和食品中的应用。本论文的主要目的是考察初始温度、压力、超临界流体浓度和喷嘴结构等因素对…平均粒径的影响更多的大小、颗粒大小分布和最终颗粒的形状。在超临界二氧化碳存在下，对聚乙二醇和聚酯进行了实验研究。结果表明，在温度高于313K、压力大于10 Mpa、CO2浓度大于70wt%的条件下，可以快速得到平均相对分子质量为4000的聚乙二醇微粒子。平均直径随着温度的降低、压力的升高和CO2浓度的增加而减小。根据能量平衡对减压过程中的温度和压力路径进行了模拟，发现随着温度的降低、压力的降低和CO2浓度的增加，聚合物处于液态的时间缩短，平均直径减小，形状变得非球形。然而，压力的影响与实验结果相反，其原因被认为是喷管内混合气速度的变化。较少