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Phase equilibrium and separation of n-dodecane–toluene–phenol in low temperature coal tar

ZHANG Haiyong1 LIU Qian1 LIU Xingkun1 ZHANG Xianglan1 XIE Qiang1 WANG Yonggang1

(1.School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing) , Beijing, China 100083)

【Abstract】The group separation of low temperature coal tar (LTCT) is important for its effective utilization. With n-dodecane, toluene and phenol as model compounds, the liquid–liquid-equilibrium (LLE) of alkane-aromaticsphenol ternary system in LTCT were obtained by experimental method and Aspen Plus simulation. The LLE of typical ternary systems during separation of the mixture by N,N-dimethylformamide (DMF) water solution were also simulated. The results showed that the ternary phase diagram simulated by Aspen Plus through UNIF-LL model fitted well with the experimental data. Toluene as a cosolvent promoted n-dodecane–toluene–phenol to be a homogeneous system. According to the solubility difference of n-dodecane, toluene and phenol in DMF and with the Hansen solubility parameters theory, n-dodecane and toluene could be separated successively from their homogeneous mixture by DMF in which different contents of water were added to adjust the polarity of solvent. Based on the optimization of extraction temperature, solvent/oil ratio and water content in solvent, n-dodecane with 93.2% purity was separated by one stage extraction with DMF, and after phase separation, toluene with 93.4% purity was obtained by adding water weighted 30% of DMF to the extract phase at 303 K and 1.5 solvent/oil ratio.

【Keywords】 low temperature coal tar; liquid–liquid phase equilibria; Aspen Plus; simulation; solvent extraction; separation;


【Funds】 State Key Research and Development Program of China (2016YFB0600305) National Natural Science Foundation of China (21506251)

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This Article


CN: 11-1946/TQ

Vol 69, No. 08, Pages 3479-3487+3293

August 2018


Article Outline


  • Introduction
  • 1 Experimental materials and methods
  • 2 Results and discussion
  • 3 Conclusions
  • Explanation of symbols
  • References