| Coal tar is a vital chemical raw material, and its important components such asnaphthalene, acenaphthene, fluorene, etc. play an irreplaceable role in many areas. Washing oil,the fraction cut at the temperature range of210~230°C, is the main raw materials forindustrial naphthalene and refined naphthalene. Naphthalene oil processing has been developedearly in China and already made a series of achievements. However, the backward technology,high energy consumption, serious environmental pollution and other problems still exist. Withthe increasing attention on the environment and energy fields, developing a green separationtechnology is becoming more and more necessary in the application of tar processing.Supercritical fluid extraction technology has the high mass transfer rate, low processenergy consumption, little environmental impact and is easy to implement the phase-to-phaseseparation. In this study, the supercritical extraction of naphthalene, acenaphthene and fluorenefrom naphthalene oil was investigated using ethanol as the solvent. The effects of extractiontemperature and pressure were taken into consideration. At the same time, the properties ofproducts were analyzed by gas chromatography (GC) to understand the extraction mechanism.In addition, the further proven experiment on the naphthalene oil achieved from Wuhan Ironand Steel Company was conducted to obtain the optimal process.The results show that the supercritical concentration rules of naphthalene andacenaphthene are similar while that of fluorine is different. The greatest extraction rate ofnaphthalene is61.43%with the concentration of1.815×10-2g/mL when the temperature andpressure are270°C and13MPa, respectively. Meanwhile, the proven experiment reveals thatthe extraction of naphthalene, acenaphthene, and fluorene from naphthalene oil by supercriticalethanol is practicable. |
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