Acta Chimica Sinica ›› 2019, Vol. 77 ›› Issue (12): 1287-1293.DOI: 10.6023/A19070279 Previous Articles     Next Articles



李雪霏, 陈玲, 许胜超, 赵文波   

  1. 昆明理工大学化学工程学院 昆明 650500
  • 投稿日期:2019-07-26 发布日期:2020-01-07
  • 通讯作者: 赵文波
  • 基金资助:

Liquid-liquid Phase-change Absorption of SO2 Using N,N-Dimethyl-n-octylamine Mixed with Hexadecane

Li Xuefei, Chen Ling, Xu Shengchao, Zhao Wenbo   

  1. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China
  • Received:2019-07-26 Published:2020-01-07
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 21666011).

A novel liquid-liquid phase-change organic amine mixed absorbent for the removal of sulfur dioxide (SO2) was developed. This absorbent could surmount the shortcomings that the atmosphere is contaminated by volatile organic solvents and a lot of energy is consumed in the process of recovering solvent in the traditional flue gas desulfurization process. The homogeneous absorption solution consists of stronger alkaline N,N-dimethyl-n-octylamine (DMOA) as absorbent and high-boiling hexadecane as a solvent, because hexadecane is the best one among various kinds of solvents tested. The solution would be automatically separated into two immiscible phases after introducing SO2 and setting. Hexadecane was in the upper phase and the absorption product of SO2 and DMOA was in the lower phase after absorption. The former could be directly recycled, and the latter could be recovered by removing SO2 from the lower phase. The absorption product was proved to be a charge-transfer complex by 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR). Subsequently, the effects of temperature, concentration and SO2 partial pressure on absorption capacity and cycle absorption performance were studied. The absorption capacity was determined by passing SO2 through the solution in gas bottle and weighing the system including the bottle and the solution. The desorption capacity was determined by passing N2 through the solution absorbed SO2, and then the content of each component in different phases was determined by gas chromatography using internal standard method. It was found that the mole absorption capacity was 2.1 mol SO2/mol DMOA under the condition of 1.013×105 Pa and 20℃, which was 38 times as much as the absorption capacity of carbon dioxide (CO2). The absorbent revealed the good cycle absorption performance in the experiment, and the DMOA could be completely regenerated under 1.013×105 Pa and 120℃. All the results showed that the mixed absorbent has good prospects for SO2 capture.

Key words: SO2 capture, phase-change, amines