Numerical Simulation And Experiment Research Of Flow And Density Field For Selective Catalytic Reduction System

Nitrogen Oxide (NOx) emissions is pollution ejected from thermal power plant and other high temperature combustion industry which is widely concerned and researched. The technology of yielding and preventing the production of NOx is usually called NOx controlling, and the technology of removing and decompounding is called NOx Denitration, simplified DeNOx.For protecting environment and decreasing NOx emissions, DeNOx technology for flue gas is gradually introduced into and increasingly widely applied in our country. Selective catalytic reduction (SCR) technology as a most popular and widely applied technology of DeNOx is worth to be introduced and absorbed significantly. But the SCR with ammonia as reducer is not completed in the efficiency of DeNOx, the utility of ammonia, and the application of system. In this case, the economy of system is low, and additional pollution is caused.The factor concerned with the efficiency of DeNOx, the utility of ammonia is divided into tow parts. First part is the activity and surface characteristic of the catalyzer, the other part is the mixing degree of flue gas and ammonia. The first is researched widely, but the other is poor. On the basis of the principle of flue dynamics and thermal transfer, the mixing degree of flue gas and ammonia is optimized. The inappropriate configuration of flue duct and the way of mixing can result in the flue gas deflection and deterioration of the catalyzer.The result of numerical simulation indicates that the flue gas deflection is high. A guide device is designed to improve the flow efficiency of the system. The configuration and amount of guide device contacts with the distribution of flue gas closely. More guide device, better distribution of flue gas, but the pressure drop is also larger. The design of ammonia injector grids (AIG) is important in the case. It is necessary to design the right system including guide device and AIG to optimize the flow.Then on the basis of Euler similar principle, experiment equipment in room temperature is built according to the numerical modeling result above. To measure the distribution of velocity and density and analyze mean difference, consequently proving the numerical modeling result, and optimizing the system.The research result in this paper can not only provide the theory of optimizing the flow duct, improving the utility efficiency of ammonia, and strengthening the reaction of SCR, but offer the method for the design of specific flow duct and ammonia injector grid of SCR system.