超临界流体(supercritical fluid)是指处于临界温度及临界压力以上的流体。它是一种处于气态与液态之间的流体状态,其密度接近于液体(比气体约大3个数量级),而粘度接近于气态(扩散系数比液体大100倍左右)。由于这些性质,超临界流体比传统的液体溶剂具有更高的传输性能,因而具有更高效的萃取分离能力。超临界流体技术,就是利用超临界状态下的流体具有的特殊溶解能力,对特定物质成分进行分离、测定、提取和精制的技术。 Supercritical fluid refers to a fluid that is above critical temperature and critical pressure. It is a fluid state between gaseous and liquid, with a density close to that of liquids (about 3 orders of magnitude larger than the gas) and a viscosity close to that of a gaseous one (about 100 times more diffusible than liquids). Due to these properties, supercritical fluids have higher transport performance than traditional liquid solvents and therefore have more efficient extraction and separation capabilities. Supercritical fluid technology, is the use of the fluid under supercritical fluid has a special ability to dissolve the specific material components of the separation, determination, extraction and purification technology.