The Research Of Membrane Contactor Separate CO₂ From The Coal-Fired Power Plant Flue Gas

As everyone knows that human activity to produce large amounts of greenhouse gas emission caused serious greenhouse effect with the speeding up of industrialization proces. At present, the technology of the CO2 control mainly used burning after removal and oxygen-enriched combustion technology. By contrast membrane gas absorption process is a new hybrid technology that combines the advantages of membranes separation and conventional gas absorption processes.It has been identified as a promising alternative technologies for CO2 removal.However as the growth of the continuous operation time, resistance of membrane phase become the main resistance of mass transfer process control, contact with ammonia hydrophobic hollow fiber membrane will be a sharp drop in the stability of the operation. Therefore, a study of the causes of membrane phase resistance increases, and the mass transfer performance of the membrane to restore, to promote the application of this technology plays an important role.The results showed that: the comprehensive performance of six kinds of single absorbent to absorb CO2 is : MEA>NH3.H2O>DEA>AAAP>MDEA>H2O. And the compatibility of the membrane: H2O>NH3·H2O >AAAP>MEA>DEA>MDEA. The absorption of ammonia was finally chosen as the main solution. Then PP membrane gas separation of CO2 absorption system is studied in the process of various operating parameters on the mass transfer performance and the effect of gas liquid two phase respectively parallel reverse flow in the shell side and tube side, the experiment respectively investigates the absorption liquid flow rate, concentration, CO2 volume fraction on decarburization rate, gas flow and mass transfer rate, the influence of the total mass transfer coefficient, the results show that the mixed gas flow velocity increases, the CO2 volume fraction in the mixture increases, the total mass transfer coefficient of falling, decarburization rate decreased, and the mass transfer rate is increasing; Increased with the increase of ammonia concentration, ammonia flow velocity, the decarburization rate and total mass transfer coefficient, mass transfer rate increased; On the basis of single factor experiment preliminarily determine the optimal experimental conditions for: 400 ml/min, gas flow velocity of liquid flow rate of 32 ml/min, liquid concentration 1 mol/L. Under the condition of the optimal parameters, stability of PP film for a long period operation of mass transfer performance recovery and regeneration after the study, the results found that found that run continuously for 15 days, the decarburization rate dropped by 50%, and mass transfer rate dropped by 46%, the total mass transfer coefficient decreased by 80%. Contact Angle measurement, SEM, XPS results show that the absorbent in the environment, the contact Angle is smaller, membrane film hole edge appear rupture, crystalline substance; Ammonia did not react with membrane silk. Thus infer that cause of membrane absorption performance is the ammonia and ammonium bicarbonate carbonate in outer surface crystallization membrane silk, blocking film hole, mass transfer resistance increased, and mass transfer performance degradation. After deionized water wash, N2 purging decarburization rate up to 80%.