Numerical Simulation And Optimization Of A Large Power Station Boiler SCR System

NOx is recognized as one of the major air pollutants worldwide in recent years. with the rapidly development of power industry, emissions of nitrogen oxides show a increasing trend year by year, so that control of nitrogen oxide emissions at the imperative of the time. The selective catalytic reduction DeNOx Technology (SCR) is the most extensive, highest DeNOx efficiency and the most promising market prospects of DeNOx Technology currently.It has become the first choice to control nitrogen oxide emissions internationally. With increasingly strict control of nitrogen oxides emissions in recent years, SCR DeNOx Technology is used more and more widely in most of our country power plant boilers. However, China is in its infancy About SCR DeNOx Technology. Currently, most of the DeNOx Technology uses foreign advanced technology, which led to the costs of the DeNOx very expensive, utilization and performance cann't be guaranteed effectively. Therefore, it become a very important significance to development DeNOx Technology,which has independent property rights and it can provide an important basis and theoretical support for SCR DeNOx in the after study.In this paper, numerical simulation of a large coal-fired Power Plant Boiler of 660MW DeNOx project and SCR DeNOx process of the system within the arrangement of deflector optimized by using fluid dynamics software FLUENT and obtain some useful results, results are as follows:through adjust the different number of deflector situation at inner SCR DeNOx system, analysis the flue velocity distribution, pressure loss, ammonia injection flow conditions, the speed of the catalyst before the standard deviation of the distribution and concentration of the impact and the angle of incidence, a comprehensive result of the arrangement of the deflector with the parameters change.The results showed that with the increase of the deflector inner the flue, the pressure loss is also increasing. Under the circumstances of no the flue deflector, overall flow parameters are poor.when the deflector increases, the flow has been some improvement. Deflector 1 has little effect,relatively deflector 1, deflector 2 is more obvious to improve of the status of the flue gas flow, and deflector 3 to the situation of speed distribution before catalyst, concentration distribution and the incident angle and other parameters have a big improvement. But only increase the number of the deflector is insufficient to meet the design requirements, and therefore simulation should be optimized about the system.In this paper, additional at 1,2 deflector, it showed flow condition has been some improvement after increase deflector inner the flue. The optimization program of the top deflector is unchang the number of deflector and adjust mounting angle, draw an optimal installation angle, and then remains the optimization result unchanged of installation angle, adjust the number of deflector consolidated results draw an optimization program. The results showed that the top of deflector is installed at angle 6°, the number of installations in 10 when it has the most optimization program.