The Simulation Of C1/C2 Separation Using Absorption-Adsorption Hybrid Method

In petrochemical industry,some gas mixtures,such as pyrolysis gas,contain C2component with high economic value.Conventional separation methods have their own practical bottlenecks.Absorption-adsorption hybrid method is a new separation technology in recent years.It has broad prospects and development potential.This paper mainly focuses on the simulation of the separation of C1/C2 with ZIF-8/water slurry or ZIF-8/ethylene glycol slurry.The method can realize continuous operation and has certain guiding value for realizing industrialization.In this paper,the equilibrium stage model is used to simulate flash evaporation in absorption-adsorption coupled separation.The research contents are as follows:（1）Used the Petal-Teja equation of state coupled with the Kurihara mixing rule to calculate the solution equilibrium of gas in liquid absorbent.The binary interaction parameters of water and ethylene glycol（EG）with pure gas in the mixing rule were determined,respectively.Used the Langmuir isotherm equation to represent the behaviour of adsorption of gas in solid ZIF-8 and the parameters in the model were determined.Correlated the osmotic pressure of EG and H₂O film surrounding ZIF-8 as a function of gas equilibrium fugacity,respectively.（2）The absorption and adsorption of CH₄,C₂H₄,C₂H₆ and N₂ by ZIF-8/water and ZIF-8/EG slurry were simulated,respectively.From the simulation results of absorption and adsorption of single component gas,it can be seen that the ZIF-8/H₂O slurry might be more suitable for the separation of hydrocarbon-containing mixtures such as CH₄/N₂ etc.than the ZIF-8/ethylene glycol slurry.（3）The single flash separation of C1/C2 mixture by ZIF-8/water and ZIF-8/ethylene glycol slurry were simulated and calculated,respectively.The simulation results of C1/C2 gas mixture show that,generally,the proposed model can represent the mixture separation process by this hybrid method of absorption-adsorption.The separation factor of ZIF-8/water slurry is better than that of ZIF-8/ethylene glycol slurry.When ZIF-8/water slurry is used as separation medium,the recovery of C2 component is relatively higher,which indicate that ZIF-8/water slurry is more suitable for the separation of pyrolysis dry gas.