Energy Study With Quantum Chemistry On Multi-Pollutants Removal From Flue Gas Using A Corona Radical Shower System

The thesis first reviewed the pollution actuality caused by flue gas from the coal-fire power plants in China, while introduced various purifying flue gas technologies including the traditional and new ones. Then the advantages of Removal of Multi-pollutants from Flue Gas Using a Corona Radical Shower System was indicated.The basis of quantum chemistry and the main theories on it were briefly introduced. Density functional theory and ab initio calculation were compared according to their properties. And the methods to calculate bond dissociation energy were summarized, as a result, the formula to calculate BDE was chosen in view of zero point energy correction while DFT were adopted. After comprehensive consideration, Gaussian98 was employed as the calculation software. The energies of free radical resources and many pollutants were calculated with B3LYP method in some basis levels.Firstly, the energies of free radical resources(NH₃+Ar&H₂O+O₂) were calculated. Based on the results, the precision of calculation were analyzed referring to experimental results of BDE. So the reliable basis set was indicated to calculate the BDEs of free radical resources. The contrast of BDEs between N₂ (main component in background gas) and free radical resources indicated that N₂ is more difficult to dissociate than free radical resources with about a 5ev difference. In theory, the background N₂ will be dissociated in higher energy so this avoids recontamination as much as possible in flue gas. The heavy influence of electron gas for removal efficiency and energy input was pointed. It also demonstrated free radicals played a key role in pollutants removal.The energies of multi-pollutants, such as benzene, toluene, xylene, ethylbenzene, naphthaline and typical PCDDs/Fs, etc., were calculated and the corresponding BDEs of side-chain were obtained. The general rule of BDEs in organic compounds were given on basis of BDE(C—C) obtained form some literatures and the calculated results.The energy value of dissociating pollutants were given according to the BDEs of various organic compounds. After combination of the corona discharge simulation of previous researchers and electron energy average distribution, the voltage of 26.5kv was indicated to result in average electron energy with 10ev and it will be enough to dissociate various pollutants in the area where electron will work.