Study Of Column Internals On Ionic Liquids Absorb CO₂

This paper used the computational dynamics (CFD) solfware to establish a three-dimentional model to predict the hydraulics performance and transfer performance at room temperature and atmospheric when imidazolium-based ionic liquids and methanol absorb CO2in four kinds of unit structured corrugated packings and in the traditional sieve tray. Eulerian-Eulerian model was selected and the unit structured packing and the sieve tray simulations are the minimal periodically structure. Four kinds of structured packings are500X,500Y and two BH-type transition structures, that is BH-a, BH-b.The simulation results indicate that the pressure drops increase with gas velocity increasing, and the liquid mass transfer coefficients have the same variation with liquid velocity. The longer the cation alkyl chain the greater the pressure drop, and are lower than methanol. With regard to the impact of imidazole anionics on mass transfer absorption process, this work choosed [EMIM]+as the cationic,[Tf2N]-,[BF4]-,[EtSO4]-,[TFA]-and [TfO]-as the anions to simulate the mass transfer process in the500X model as well as methanol. The results show that [EMIM][EtSO4] has the largest pressure drop and [EMIM][BF4] has the greatest liquid mass transfer coefficient. In four different configuration packings the pressure drops follow the order of500Y> BH-a> BH-b>500X, and the liquid mass transfer coefficients are in the order of BH-b>500X≈BH-a>500Y. The results tell us two transition structures promote the mass transfer processIn the case of the impact of cations and anions on the pressure drops, the sieve tray, whose liquid inlet size is270×30mm, simulation results have the same results with the structured packings. When changing the size of the liquid inlet, the clear liquid heights decrease along the x-direction gradually, and the clear liquid distributes nonuniform. The clear liquid height follows the order of270×40mm>270×30mm>270×50mm. The liquid holdup decreases along the dispersion height increases in z-direction, and near the plate the liquid holdup is large.