Simulation Of Ionic Liquids In Gas Dehydration

Carbon dioxide is a kind of widely used materials.But industrial production of carbon dioxide always contains water vapor and sulphide gas.These impurities can be harmful to the transport pipeline.So in my paper,the main research is the dehydration of carbon dioxide.IL is a new type of green solvent in modern times,which has many advantages,such as no vapor pressure,good solubility and environmental pollution.In this paper,IL was used as an absorbent.Firstly,IL can absorb both CO2 and water vapor and the solubility of carbon dioxide in[EMIM][Tf2N]is just 0.03 mole fraction.So in this paper,[EMIM][Tf2N]was chosen as absorbent.The saturated steam method was used to measure the gas liquid equilibrium.Before the experiment,UNIFAC model and COSMO-RS model was used to predict the pressure.Then,the saturation vapor pressure within temperature range of 323.2 K-358.2 K and the composition range of 0.1?1.0 were measured and compared with the predicted value.Research results show that IL can reduce the water vapor pressure under the same temperature.In the lower water content,the vapor pressure of the system is increased with the increase of temperature and predicted data is closed to the experimental data.Besides,ZIF-7 and ZIF-8 were prepared by hot melt method.Then a certain amount of ZIF-7/ZIF-8 was put into IL to study the effects of their combined action.Finally,the flow condition of the sieve plate was simulated by CFD.The plate pressure drop,the velocity distribution and concentration distribution was researched at different gas or liquid velocity.The results show that the pressure drop is concentrated in the liquid layer.Because of the interaction of gas and liquid the velocity direction changed near the holes.The liquid flow has a certain reflux near the weir and inlet area.The liquid hold up and the pressure drop of the plate are decrease with the increase of gas's velocity.The increasing of the inlet speed of the liquid can increase the fluid volume and the pressure drop.ZIFs particles suspended in the ion liquid are evenly distributed in the sieve plate,and the particles have no accumulation due to the interaction of the gas phase.Compared with the flow of the ionic liquid without the ZIFs,the addition of ZIFs reduces the pressure drop of the plate and enhances the mass transfer.