关键词: 选择催化还原, 烟气脱硝, 数值模拟, 导流板

Abstract: The distribution of flue gas flow field and the effects on mixing the reducing agent （NH3） with NOx in SCR system are important in the denitrification. Therefore，the structure optimization by numerical simulation of newly designed SCR reactors is essential in the SCR reactor design. In this research FLUENT software was used to simulate flue gas flow field，the effects on mixing NH3 with NOx at the entrance of the first layer catalyst，and the pressure drop of the system in a 300MW coal-fired power plant. Results showed that the relative standard deviation of flue gas velocity was less than 15% between the above and below section of AIG (ammonia injection grid)，the entrance of the first layer catalyst and the outlet of SCR reactor after structure optimization in the BMCR (boiler maximum continuous rating) conditions；the relative standard deviation of NH3/NOx ratio was less than 10% at the entrance of the first layer catalyst；the maximum deviation angle of the flue gas entrance at the entrance of the first layer catalyst was between ?10° and 10°；the pressure drop of the system was less than 800Pa. Using well-designed deflectors could inhibit the flow separation phenomenon caused by bending and variable cross section，eliminate the high swirl，and make it more smoothly for the flue gas entering the catalyst.

Key words: SCR, flue gas denitrification, numerical simulation, deflector