Application of CFD in the optimal design of a SCR–DeNOx system for a 300 MW coal-fired power plant

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–DeNOx 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.

► It focus on a real SCR–DeNOx system operated in a 300 MW coal-fired power plant.
► The mixing process of flue gas and ammonia are investigated by 3-D CFD simulations.
► The performances of the existing gate leafs and hybrid grid are investigated.
► An improvement of the gate leaf and its effect are discussed in detail.
► The thickness of the straightener for the current facility is determined.