Study On Preparation Of Nano-magnesia Adsorbent And Performance Of Flue Gas Simultaneous Desulfurization And Denitrification

The pollution caused by sulfur dioxide and nitrogen oxides in our country turns out to be very pressing. The nation is devoting a lot of energy on taking care of the air pollution. Hence it is quite necessary and urgent to develop a new economical, efficient and simple way to carry it out. Nano-magnesia has some good nature, such as small size, large specific surface area, high purity, high hardness, high reactivity, strong adsorption, good low-temperature sintering, which can be used as environmental pollution control adsorbent. This paper systematically studied on preparation of nano-magnesia powder and adsorbent, and the adsorbent was used on experiment of simultaneous desulfurization and denitrification,which obtain a good effect.The paper introduced the nature, use and preparation methods of nano-magnesia, and carried out in-depth research on preparation methods of nano-magnesia powder and adsorbent. Using MgSO4·7H2O and Na2CO3 as raw material, polymer (PEG1000) as surfactants, nano-magnesia powder with good crystallinty and large specific surface area has been synthesized by direct precipitation and microwave heating in water bath combining method. The effects of reaction temperature and time, calcination temperature and time, and the dosage of polymer (PEG1000) on the powder specific surface area were studied in detail. The morphology and structure of nano-magnesia powder were characterized by means of thermogravimetry analysis, X-ray powder diffraction (XRD), scan electron microscope (SEM), Fourier Transform Infrared Spectrophotometer (FT-IR). And thermal decomposition temperature of the basic of nano-magnesia was analyzed by thermogravimetry. The results showed that nano-magnesia powder whose specific surface area was 183.35 m2/g and average particle size was about 7.2nm was prepared by decomposing nano-magnesia basic at the temperature 500℃for 1.5 hours. Adopting blend methods to prepare nano-magnesia adsorbent (nano-magnesia powder: MgSO4·7H2O:sweet-powder= 75:32:1). And characterizing the adsorbent before and after simultaneous desulfurization and denitrification.The nano-magnesia adsorbent simultaneous desulfurization and denitrification performance were studied through self-designed and installed devices, and the influencing factors of desulfurization and denitrification efficiencies were analysed in detail. The result showed that adsorption of desulfurization efficiency can be maintained at about 98.03 percent and denitrification efficiency can be maintained at about 85.74 percent in flue gas temperature 150℃, bed height 5cm,7.5 percent amount of oxygen, sulfur dioxide concentration 2000 mg/m3, nitric oxide concentration 500mg/m3 under the conditions within 60 min. The adsorbent has good stability, and the desulfurization and denitrification efficiency were 41.52 percent and 25.72 percent respectively within 180 min.