Entrainment Model of Fluidized Bed Particles and Its Application in Flow Field Optimization of Denitrification Systems

Abstract

Aiming at engineering challenges of SCR denitrification systems in coal-fired power units, including empirically dependent flow field regulation, uneven distribution of catalyst particles and excessive ammonia slip, this paper conducts research on cross-scenario adaptation and engineering application of a fluidized bed particle entrainment model. Based on gas-solid two-phase flow theories in thermal energy engineering, the core framework of the traditional dense-phase entrainment model is retained, and three correction factors (low-velocity drag force, low solid holdup attenuation and confined structural damping) are introduced to reconstruct a quantitative calculation model suitable for the low-velocity, low-solid-holdup confined flow field inside SCR reactors. A refined optimization methodology is established, featuring quantitative model evaluation, iterative adjustment of structural parameters and on-site working condition verification. Engineering validation is carried out on a 300 MW power unit, and multi-dimensional optimizations are implemented including flow guide structures, zoned ammonia injection and catalyst layer layout to effectively homogenize gas-solid distribution inside the reactor. Field test results demonstrate that after optimization, the non-uniformity coefficient of flue gas velocity drops to 14.3%, the effective coverage area of catalysts rises by 22.6%, the system denitrification efficiency remains stably above 98%, and the ammonia slip concentration is controlled within 2.5 mg/m³. This study verifies that the traditional fluidized bed flow model can be efficiently adapted to denitrification scenarios via parameter correction, offering an innovative technical pathway for quantitative optimization of denitrification flow fields.