Simulation of Steam's Wet Phase-Transition Agglomeration Technology and Optimization of Steam Heterogeneous Nucleation Models for Coal-Fired Power Generation.

Abstract

Traditional dust removal technologies have relatively low capture efficiencies for PM2.5 (particulate matter ≤2.5 μm) emitted by coal-fired power plants. The wet phase-transition agglomeration technology can enhance the removal efficiency of PM2.5. However, its mechanisms are not well-understood. In the present work, the Fletcher heterogeneous nucleation model was modified. Line tension and surface topography characteristics were incorporated into the modified model. By integrating with the computational fluid dynamics-population balance model (CFD-PBM) coupled simulation, the impacts of various key parameters on the agglomeration behavior of particles were analyzed. The results demonstrated that the error between the results obtained from the modified model and the experimental data was less than 3%, indicating remarkable improvement in the prediction accuracy. The sensitivity analysis revealed that supersaturation had the most pronounced influence on the critical free energy. Increasing the supersaturation could effectively promote the agglomeration of fine particles. The simulation results indicated that the addition of steam to the heterogeneous nucleation zone was conducive to the agglomeration of particles and significantly boosted the removal efficiencies of micron- and submicron-sized particles.