摘要/Abstract
为了克服传统脱硫工艺胺法脱硫中挥发的吸收剂污染空气以及吸收剂回收过程能耗巨大的缺点，开发了一种新型液液相变有机胺混合脱硫体系.将碱性较大的吸收剂N，N-二甲基正辛胺（DMOA）与沸点较高的溶剂十六烷混合形成均相溶液.其在吸收二氧化硫（SO2）后自动分为两相，十六烷在上相，SO2与DMOA反应的产物位于下相.上相十六烷可以直接进行循环利用，将下相溶液中的SO2脱除即可实现DMOA再生.经核磁共振氢谱（1H NMR）和傅里叶红外光谱（FTIR）表征发现，SO2和DMOA的反应产物为电子转移产物.在压力为常压、温度为20℃的条件下，混合体系最多的摩尔吸收量为2.1 mol/mol，是同等条件下混合体系CO2摩尔吸收量的38倍.该混合体系具有良好的循环吸收性能，在常压、120℃的条件下进行解吸操作基本可以完全循环再生DMOA.这些结果表明该混合体系用于吸收SO2具有良好的前景.
关键词: SO2吸收, 相变, 有机胺
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
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