Separation of phenolic compounds from medium low temperature coal tar (MLTCT) is an economic and efficient way to obtain phenolic compounds. The traditional method to separate phenols from coal tar is chemical extract phenols using aqueous alkaline solutions and then to acidify the extract using acids to recover the phenols. The disadvantages of the method are the use of large amounts of both strong alkalis and acids, and the production of excessive amounts of waste water containing phenols. Therefore, the development of a high efficiency separation of phenolic compounds from MLTCT is conducive to the clean and efficient use of MLTCT. In this paper, an extractive distillation approach was applied to separate the phenols from the phenol oil fraction (170–210 °C) in the MLTCT. Gas chromatography combined with mass spectroscopy and flame-ionization detection (GC–MS/FID) qualitative and quantitative characterization of the carbolic oil, the extractive distillation phenolic compounds of the carbolic oil processing design are studied. The triethylene glycol (TEG) as extractive solvent is applied in this system. The binary parameter of the coal tar component vs. the TEG is studied in this paper to improve the accuracy of the calculation. A simulation of the extractive distillation process had been carried out in this article by using Aspen Plus Version 8.4. Parameter variations and technology conditions were performed to investigate the influence of each unit specific operation conditions on the performance of the system. The extraction rate of the phenolic compounds in this study is 96.5% with 93.4% phenolic compounds purity. The energy use of the process is 3.12 MJ/kg-phenolic compounds, and CO2 emission is 0.45 kg / kg-phenolic compounds. Compared to the traditional aqueous alkaline method the new process can save 36.5% of energy consumption, and reduce 90% of CO2 emission.

Extractive distillation approach for separation phenolic compounds from phenol oil fraction in medium-low temperature coal tar

2019 Spring National Meeting

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