油酸-甘油-无水乙醇共混体系与超临界 CO2的相平衡Phase equilibrium of oleic acid-glycerol-anhydrous ethanol co-blended system with supercritical CO2

Abstract

旨在为生物柴油后处理阶段的超临界CO2提纯工艺提供参考数据，以生物柴油生产过程中后处理阶段体系所含的油酸、无水乙醇及甘油为原料，通过在SYLG-01型超临界流体相平衡实验装置中，观察油酸-甘油-无水乙醇共混体系在温度为308 K下与CO2达到相平衡状态的过程。结果表明，油酸-甘油-无水乙醇共混体系为液-液两相，与CO2在相平衡实验装置内最开始是气-液-液态，随着压力的增加，当CO2达到超临界状态时，不同相之间的流动性和传递性增强，共混体系变成了均一态。因此，改变超临界CO2的压力，有望将体系中的游离脂肪酸和副产物甘油同时萃取分离。 Aiming to provide reference for the supercritical CO2 purification process in the post-treatment stage of biodiesel production, oleic acid, anhydrous ethanol, and glycerol contained in the system in the post-treatment stage of biodiesel production were used as raw materials, and the process of oleic acid-glycerol-anhydrous ethanol co-blended system reaching phase equilibrium in CO2 at a temperature of 308 K was observed in the SYLG-01 supercritical fluid phase equilibrium experimental device.The results showed that the oleic acid-glycerol-anhydrous ethanol co-blended system was a liquid-liquid phase, and it was gas-liquid-liquid state at the beginning with CO2 in the phase equilibrium experimental device,and as the pressure increasing, when CO2 reached the supercritical state, the mobility and transferability between different phases were enhanced and the co-blended system became homogeneous. Therefore, changing the pressure of supercritical CO2 could extract and separate the free fatty acids and by-products glycerol in the system at the same time.

Keywords

• 超临界流体；油酸；甘油；相平衡状态
• supercritical fluid; oleic acid; glycerol; phase equilibrium state