Study On SO₂ Absorption By Liquid-liquid Phase Change In Organic Amine Solution System

Sulfur dioxide?SO₂?is a major atmospheric pollutant and is the culprit in many environmental problems.In order to reduce SO₂ emissions and reduce environmental pollution,we must take effective measures to capture and sequester SO₂ in flue gas.In this paper,the liquid-liquid phase desulfurization technology of organic amine non-aqueous solution system was studied.This method reduces the amount of subsequent work by reducing the phase shift in SO₂ absorption process and enriching SO₂ in one phase,thereby reducing the energy consumption of the desorption process.In this paper,N,N-dimethylaniline,N,N-dimethylcyclohexylamine and N,N-diethylethanolamine,which are excellent in SO₂ absorption,are used as SO₂absorption.The agent is prepared by using an organic solvent having a high boiling point,a low viscosity and being chemically inert to SO₂,to prepare a SO₂ absorption solution and to achieve liquid-liquid phase absorption of SO₂.The specific research content includes the following aspects:Firstly,a suitable organic solvent and a tertiary amine are selected to form a non-aqueous SO₂ phase change absorption solution.After absorbing SO₂,a liquid-liquid phase separation is achieved,and the maximum SO₂ absorption capacity can reach2.37 mol SO₂/mol organic amine,and SO₂/CO₂ The selectivity is higher,and the maximum value is 627.As far as we know,this data is the maximum reported in the literature.The structure of the absorption product was confirmed by nuclear magnetic resonance?NMR?,Fourier transform infrared?FTIR?spectroscopy and CHNS organic element analysis,and it was confirmed that the absorption product of the tertiary amine was mainly an electron transfer product under anhydrous conditions.The structure of the SO₂ absorption product is relatively stable,is not easy to absorb water and is oxidized,can be stored in the air for a long time,and the electron transfer force between the organic amine and the SO₂ is weak,and the SO₂ can be released at 80°C,the regeneration rate of the absorbent exceeds 99%.We have studied the physical properties of absorption solutions of different absorbent/organic solvent ratios,such as viscosity,saturated vapor pressure or thermal stability,which proves to have the advantages of low viscosity and low volatile loss.Subsequently,the mechanism of liquid-liquid phase change was speculated and proved.The distribution of the three components in the liquid phase of the absorbent,solvent and SO₂ was studied with the change of conditions,and the different absorption conditions were studied.The effect of SO₂ absorption load and the removal rate of SO₂ in the simulated flue gas.At the same time,desorption of the product after the phase-change absorbent absorbs SO₂ was explored.In addition to the traditional thermal desorption,the possibility of chemical desorption was also explored.