Selective catalytic reduction (SCR) with ammonia or urea is regarded as one of the most important technologies to reduce the NOx emissions from coal-fired power plants. However, the design and development of SCR-DeNO(x) systems are a complicated process involving the optimization of several parameters such as the ammonia/urea injection strategy, the installment of the gate leaf and the hybrid grid, as well as the thickness of straightener. These parameters determine the velocity and concentration distributions at the entrance of catalyst layers, which are key factors to affect the efficiency of flue gas denitrification and ammonia slip. In this work, CFD simulations are carried out to portray the performance of the SCR-DeNOx facility in a 300 MW coal-fired power plant. The influences of the gate leaf, hybrid grid and straightener on the distributions of the velocity and concentration are investigated. And then the corresponding experiments are performed to qualitatively confirm the simulation results. (C) 2012 Elsevier Ltd. All rights reserved.