Numerical simulation of ash erosion in the selective catalytic reduction catalyst of power plant boiler

Abstract

The selective catalytic reduction (SCR) catalyst of a 660 MW ultra-supercritical once-through boiler denitrification system suffered severe abrasion, causing the denitrification system to fail. Statistics showed the abrasion area focused on near side of the boiler. The formation mechanism of the catalyst abrasion is analyzed using general purpose computational fluid dynamics (CFD). The simulation results are consistent with the actual test data. It reveals that the catalyst abrasion is likely to be caused by the nonuniformity distribution of the fly ash particle field. The fly ash distribution and the gas velocity in different cases were obtained. Under the best case, the impact device can ensure fly ash particles in the upper part of catalyst move to the far boiler side of catalyst. It is shown that the flow field and fly ash particle distribution greatly improved after computation of the optimization.