Experimental Study On Separation Of Propylene/Propane By Ionic Liquids

Cryogenic separation is the main method of propylene/propane separation in industrial production.Cryogenic separation method can effectively separate propylene/propane,but there are many problems,such as large equipment investment and high energy consumption in production process.The absorption separation techonogy has the characteristics of high absorption efficiency,low energy consumption and low cost.However,the traditional absorption separation method,mainly using organic solvent as absorbent,easily lead to gas pollution,and its high solvent loss rate leads to its limitation of industrial applications.Ionic liquids have many advantages such as excellent thermal stability and low vapor saturation,which gain lots of attention.We synthesize two kinds of ionic liquids[BMIM]Cl-CuCl and[BMIM]SCN-CuSCN,and mix the two kinds of ionic liquids with organic solvent for the absorption of propylene and propane at 298 K and 0.1-0.7 MPa.The experiment found that the ionic liquids mixed with toluene has better ability to absorb propylene,and ionic liquids mixed with MEA not only promoted the propylene absorption performance also retained the good separation performance.And[BMIM]Cl-CuCl-MEA was chosen to get further research.The results showed that the absorption and separation of propylene/propane increased with the increase of the complex ratio,but when the complex ratio was over 5:1,the absorption performance decreased.And[BMIM]Cl-CuCl-MEA is regenated after absorption experiment.After 5 cycles of experiment,found that the performance of absorbent regeneration after not much difference between the fresh solvent,it proved that[BMIM]Cl-CuCl-MEA have recycling capacityThe absorption and separation properties of[BMIM]Cl-CuCl-MEA is studied under the conditions of 298 K,total gas pressure 0.2-0.4 MPa,and the mole fraction of propylene was 50%-80%.The experimental results show that[BMIM]Cl-CuCl-MEA has the best separation performance for propylene/propane.Under the condition of 298 K and 0.2 MPa,[BMIM]Cl-CuCl-MEA has the best separation performance for mixed gas,and the separation coefficient of propylene/propane is up to 44.1 when the mole fraction of propylene is 80.3%.