Research On Regulation Method Of Flue Gas Flow Field And Optimization Of Low Pressure Loss In SCR-DeNO_x System In Coal Fired Power Plant

In 2015,Jing Chai's "beneath the dome" has aroused concern for air pollution of China.Nitrogen oxides(NOx)produced by a large number of coal fired power plants in China has different degrees of toxicity,which causes serious damage to human and environment.Thirteenth Five-Year Plan on environmental protection put forward new requirements that NOx emission is reduced about 5%.In order to achieve emission standards,more and more power plants begin to use flue gas denitrification technology,to a large extent,reducing the emission of nitrogen oxides.At the same time,the flue gas denitrification technology has been developed rapidly in China.In this thesis,the most widely used flue gas denitrification technology,Selective Catalytic Reduction(SCR),the computational fluid dynamics(CFD)software for simulation of the model,model theory and other main contents are introduced.Focused on the common 660 MW coal fired power plant ‘?' and ‘tower' type flue gas denitration system,this thesis mainly studies on the CFD modeling and flow field optimization design.Complex structures are involved: arc corners,high-angle diagonal corners,irregular variable diameter structure,bidirectional variable diameter structure.The flue gas flow field in complex structure is analyzed in detail and the flow control method is researched,which can effectively improve the gas velocity distribution and ammonia concentration distribution in the complex structure,and improve the efficiency and life of the catalyst in the flue gas denitrification system.The pressure loss of the system is the technical and economic index of the energy consumption of the system.Finally,the key structure and the shape of the flue are optimized to reduce the pressure loss during operation and to make the system more energy efficient.