Study On The Absorption Of CO₂using Hollow Fiber Membrane Contactors Based On Functionalized Amine Solution

In order to effectively respond to the deterioration of the environment and the development of low carbon economy, how to control and reduce the emission of CO2has become an important strategic choice.In this paper, new functionalized alkanolamines ionic liquids are synthesised as the main material based on the traditional alkanolamines absorbers and organic/inorganic acids, and to investigate the structure of four functionalized alkanolamines ionic liquids ([DETA][HCOO],[TETA][HCOO],[DETA]L,[TETA]L). Raman spectroscopy is used to characterize the new material, and the molecular formulas of [DETA][HCOO],[TETA][HCOO],[DETA]L,[TETA]L have been analyzed.To evaluate the performance of abosorption and desorption to CO2based on the chemical absorption, all the functionalized alkanolamines ionic liquids made above are tested to select the absorbent which has the best performance. Sort of absorptive capacity of the absorbents is as follows:[TETA]L>[TETA][HCOO]>[DETA]Ac>[DETA]L, and sort of desorptive capacity of the absorbent is as follows:[TETA]L≥[TETA][HCOO]>[DETA]Ac>[DETA]L. The absorption capacity is in the range of0.3-0.75mol/mol, and the mass transfer efficiency is in the range of2.8-6.Omol/(m2·-h). The desorption temperature of functionalized ionic liquids is in the range of40～80℃, much lower than traditional absorbers with the largest decline of54.2%. The result shows that functionalized ionic liquid is better than the traditional absorbers.In order to test it’s performance to abosorb CO2and the effects of various factors based on the membrane contactor,[TETA][HCOO] and [TETA]L is chosed to be tested during the reaction process. The result shows that the removal rate of CO2decreases with the increase of gas velocity, and increases with the increase of liquid velocity, and the total mass transfer rate increases with the increase of gas velocity and liquid velocity. The CO2removal rate and mass transfer rate increase as concentration increased in the low concentration range, and the removal rate and mass transfer rate decrease with increasing concentration rise in the higher concentration range because of the effects of viscosity. The most optimal concentrations of [TETA]L and [TETA][HCOO] are respectively1.0mol/L and0.6mol/L with the optimal removal rate for CO2of100%and99.5%. From what has been discussed above, the new functionalized ionic liquids are better than the tranditonal absorbents. At the same time, some reseach about mass transfer is analysed based on the mass transfer separation and recovery of CO2by hollow fiber membrane contactor. The factors are analysed through mass transfer coefficient, and the results showed that the influence is similar with the previous experimental results.