The Study On A New Method For Flue Gas Denitration Of Marine Diesel Engine

The study on the new method for flue gas denitration of marine diesel engine, which primarily has discussed two key things, one is how to get hydroxyl (·OH) radicals using high concentration and high efficiency, and the other one is how to remove NOx via radicals oxidation. In this paper, NOx removal directly by using radicals injection has been realized in the exhaust pipe of the marine diesel engines.Using strong electric-field ionization discharge method, water vapor and O2are ionized, decomposed, and excited extremely into radicals, such as03、O2+、H2O+、H2O2and so on. The radicals will transform into·OH, when they are injected into the pipe. The·OH radicals are generated accompanying a complicated process, which includes lots of plasma chemistry reactions. Being one of the most active radicals,·OH can oxidize NOx into HNO3on high speed. The method for NOx removal from flue gas by radical injection without catalyst and absorbent additive, don’t need to depend on traditional desulphurization either. In the whole process, there is no new pollution appears. This method will be an environment-friendly and efficient method. And compared to the selective catalytic reduction technology, the volume of plasma generator is smaller, one-time investment and running costs are significantly reduced, this new method not only has high nitrogen oxide removal rate, but is also effective in reducing other pollutants of diesel engine exhaust, such as hydrocarbon, carbon monoxide, sulfur dioxide and so on.According to the theory of gas discharge physics, plasma chemistry, macro dynamics, the processes of radicals formation and·OH conversation are represented, and reaction mechanics of NOx oxidizing by radicals are discussed with mathematics model helping. The research results show that, in oxygen radicals, the concentrations of ozone can reach240mg/L, the positive and negative ion achieve to the level number1016per cubic meter. The particles will be converted into hydroxyl free radical efficiently while be put into the pipeline. Meanwhile, this method can obtain the effect of nitrogen oxide removal rate up to more than95%, at the same time the recovery rates of NOx can reach as high as82.5%. The research has solved the problems of the diesel waster gas treatment at home and abroad, if succeed, it would be widely used in ship.