Optical Fiber Reflectance Probe for Detection of Supercritical Transition

A fiber-optic reflectance probe is developed for the fast, in-situ detection of supercritical phase change in multiphase and multicomponent systems. Experiments with the binary mixtures of methanol-cyclohexane and CO2-methanol were conducted to demonstrate the usefulness of the reflectance probe in accurately capturing the supercritical transition in both liquid-liquid mixture and gas expanded liquids. The results for the supercritical temperature and/or pressure correlate well with those found in the literature. The probe itself can be used up to pressures of 140 barg and temperatures of 120 °C.