Experimental Study On Separation Carbon Dioxide From Flue Gases Using Hollow Fiber Membrane Contactor

Global warming is becoming one of most important environmental problem due to the worse of greenhouse effect mainly by a great deal of greenhouse gases emission. CO₂ is the main greenhouse gas that contributes to greenhouse effect. Plants using fossil fuels are the concentrative emission source of CO₂. With the development of economy and the increase of demand for power, the amount of CO₂ emission becomes larger. So it is very important that study on the separation of CO₂ coming from coal-fired flue gas to control the global wanning and greenhouse effect. Membrane absorption is the new technology to separate CO₂. And it possesses the benefit of equipment compactness related to membrane separation and the benefit of process selectively related to the chemical absorption process. It indicates that it has a great potential for CO₂ separation.First, the absorption mechanism about some solvents was tested in the thesis. The absorption and regeneration performance of aqueous MEA, MDEA and AAAP were studied. The results showed that aqueous MEA and AAAP have good absorption performance and aqueous MDEA has good regeneration performance. Base on that, the blended absorption solutions made of difficult concentrations of aqueous MDEA with MEA and AAAP as addition agents were tested. The results showed that the absorption performance of blended absorption solutions is great better than single aqueous MDEA.A pilot-scale hollow fiber membrane contactor experimental for CO₂ separation from flue gas, which used the central distribution pipe, was designed and built up. Using aqueous MEA, MDEA and AAAP as absorption solutions, the separation experiments were tested. Effects of the solution temperature, flow rate, and concentration of absorbents, and the flow rate of flue gas as well as the concentration of carbon dioxide in the flue gas on the removal efficiency and mass transfer rate were studied. The experiments about CO₂ separation from the real flue gas were tested and compared with that from simulated flue gas. And the singular cycle experiments were tested. The results showed that aqueous AAAP has the best absorption performance among three absorption solutions. And the aqueous MDEA was easieat to be regenerated. The aqueous MEA is easier to be regenerated than aqueous AAAP, but also easy to be wetting. It is also noted that the transfer mass rate increased with the concentration of CO₂ in flue gas.