Study On Flue Gas Desulfurization Using Membrane Absorption And Membrane Distillaiton Technology

China is a big country for manufacture and consumption of industrialproducts and commodities, which at the same time would also lead to seriousenvironmental problems.“The Eleventh Five-Year Plan” clearly puts forwardgoals on building a resource-saving and environmentally-friendly society, andthe environmental protection program has proposed a more stringent target for2010, requiring that the major pollutants-sulfur dioxide emissions and CODshould be reduced by10%compared to the quota achieved at the end of the“Tenth Five-Year Plan”. As regards the sulfur dioxide emissions, theproduction of sulfur dioxide estimated according to the empirical formula andthe historical curvefitting method, such as the emission intensity projectionmethod, will reach45million tons in2010. According to the outline of theenvironmental protection targets envisaged in the “Eleventh Five-Year Plan”the emissions of sulfur dioxide in2010must be reduced by10%compared tothe figures in2005, aiming to control the emissions of sulfur dioxide at23million tons, so that the target for removal of sulfur dioxide should reach22million tons, which would requires an increased and improved enforcement ofdesulfurization activities and effective control of sulfur dioxide concentrationin the atmosphere.The flue gas is a major source of sulfur dioxide, and in order to controlthe sulfur dioxide in the atmosphere, the control upon sulfur dioxide pollutionis an important and urgent task, and is also a worldwide problem. The studyon desulfurization of sulfur dioxide has long been carried out at home andabroad, and there are more than a hundred varieties of methods for treatingsulfur dioxide gas. However, only a few dozen of these methods have foundcommercial application, because these methods for reduction of sulfur dioxideemissions must bring about positive effects, while leaving those processeswith high treatment costs and low economic benefits in the lurch. Therefore,the development of new cost-effective methods for treatment of sulfur dioxidegas is the key for solving this problem.Gas-liquid contactor equipped with polypropylene （PP） micro-poroushydrophobic membranes was applied for removal of sulfur dioxide from flue gas.30%MDEA solution were adopted as the absorbent. The performance ofthe hollow fiber membrane （HFM） for absorption of SO₂was evaluated interms of the gas and liquid flow rate, the absorbent temperature, the gasresidence time in PP HFM, it was found that the desulfurization efficiency canup to86%by this approach.Flue gas desulfurization using compound methyldiethanolamine （MDEA）aqueous solution have high absorption efficiency, and the waster solutionregeneration technology research improved it to meet the “Energyconservation and emission reduction” plan in china. Using ceramic hollowfiber membrane contactor as regenerator, vacuum membrane distillationmethods to regenerate waster MDEA aqueous solution that absorbed so2fromflue gas. Experimental study the relationship between the solutiontemperature and regeneration efficiency also study the relationship betweensolution temperature and the vacuum membrane distillation flux. From thechromatograms it is clear know that the best temperature for VMD is70℃,and the regeneration efficiency can up to98%at this experimentalconditions.The mathematical model of desulfurization efficiency in hydrophobichollow-fiber membrane was set up respectively by using of the mass transferempirical correlation and differential equation. The results from the model arein good agreement with the experimental data.