Study Of Concentrated Seawater Flue Gas Desulphurization By Membrane Absorption

Sulfur dioxide, coming from burning coal, is one of primary air pollutants. It's important to develop flue gas desulfurization with self-dependent intellectual property as well as in favor of developing recycle economics and integrated utilization resources, which has great significance in promoting energy-saving technical progress in reducing emissions and our country's improvement of atmospheric quality.Membrane based gas absorption is a new combined membrane process that includes membrane technology and gas absorption technology. It has more advantages than the conventional absorption.The chemical component concentration of the concentrated seawater which is emitted by the project of seawater desalination and seawater circulating cooling technologies is twice as the original seawater. If the concentrated seawater can be used into flue gas desulfurization, it will not only lower the absorption cost, but it can also realize the recycling of the concentrated seawater.So far, no research of concentrated seawater flue gas desulphurization by membrane absorption has been reported.The experiment first analyses the quality of the concentrated seawater and seawater, then characterizes the polypropylene hollow fiber membrane. It initially confirms that the concentration seawater can be used into flue gas desulfurization as absorbent. According to the pore size and molecule free path, it determines that the gas diffusion mechanism is transitional diffusion.Secondly, removal of Sulfur dioxide from simulated flue gas is studied in a hydrophobic polypropylene hollow fiber contactor, using concentrated seawater and seawater as absorbents. The effects of various factors such as flux of absorbents, flux and concentration of gas mixtures, pressure drop between gas and liquid on desulfurizing efficiency are investigated. The results show that concentrated seawater has a large capacity and high efficiency rate of desulphurization compared to seawater. The desulfurizing efficiency with concentrated seawater was twice as seawater at the same condition (absorbents flux 10L·h-1, gas flux 1000 L·h-1). Membrane contactor can maintain the repeated operation steadily with the concentrated seawater, and have some industrialized application prospect.At the last using the existing mass transfer theories as the researching basis, the mass transfer coefficient of gas phase, membrane phase and liquid phase are quantitative and qualitative analyzed. The results show that the total mass transfer coefficient increases with the liquid or gas flow rate, the gas phase SO2 concentration has little effect on the overall mass transfer coefficient.