The Membrane Contactor For The Separation And Recycling Of Carbon Dioxide In The Flue Gas

Carbon dioxide can be selectively removed from flue gases using commercially available absorption equipments. These processes are, however, energy intensive and the resulting equipments used are rather large. The increasing in power costs prevents large-scale application. Membrane contacting process which is a hybrid membrane gas absorption process combining the advantages of absorption (high selectivity) and membrane (modularity, small size) is a worthwhile alternative especially for power plant flue gases.Hydrophobic microporous hollow fiber membrane contactor was designed and used to separate CO2 from simulated flue gas mixture (CO2, N2, O2) with aqueous absorbent such as monoethanolamine (MEA), methylethanolamine (MDEA) and potassium glycinate (PG) . The absorption experiments were carried out under some conditions of different temperature, gas flux, concentration and liquid flow rate. The factors that influence CO2 removal efficiency were investigated. It was found that CO2 can be well took off when membrane modules is series-connected; The CO2 removal efficiency increases with the increase of liquid flow rate and the concentration of absorbent while decreases with the increase of gas flux and the COa concentration in the mixture gas. Under the same operating conditions, potassium glycinate solution exhibits the highest absorption capacity and the worst desorption capacity among three absorbents here. The experiment still discussed how to reuse the absorption liquid and make it recycled.A mathematical model for overall mass transfer coefficient was developed. The calculated results show that the overall mass transfer in the COi- MEA system can be described by this model. Based on this model, the behavior of membrane contacting process was examined, we can easily found that which is the dominating one and how to optimize the process.