关键词: 烟气脱硫, 数值模拟, 气液两相流, 实心锥喷嘴, 空心锥喷嘴, 喷淋效果, 液相分布, 塔壁磨蚀

Abstract: Numerical simulation for spraying effects of desulphurization towers with solid and hollow cone nozzles were investigated respectively by computational fluid dynamics (CFD) method, through which the diffusion and distribution characteristics of slurries were obtained, and the erosion on the tower shell made by impingement of near-wall slurries was also explored. The main results are as follow. No matter what types of nozzles are used in four-layer spray, the profiles of gaseous velocity magnitude, pressure, turbulent kinetic energy and temperature fields are alike, and the liquid phase contributes to the similar rectification effect of flue gas. For the spray layers with solid cone nozzles, the mass concentration of droplets and the thickness of the liquid film on the tower shell increase gradually from the top to the bottom. Sprayed from hollow cone nozzles, intensive slurries near the tower shell jet out in umbrella-shape film and impinge severely on the wall，generating high-concentration arc one by one on the wall，while the droplets rebounding from the wall create low mass concentration areas beneath the arcs. The higher the liquid mass concentration on the wall is, the higher the local erosion rate is.Corresponding to the four-layer spray taking hollow cone nozzles, four waved belts of high erosion rate appear on the shell. Taking the hollow ones as near-wall nozzles, the maximum wall erosion rate in spraying zone is 5 times as much as that taking solid cone nozzles. Thus, solid cone nozzles is the best choice for near-wall nozzles in spray towers.

Key words: flue gas desulfurization, numerical simulation, gas-liquid two phases flow, solid cone nozzle, hollow cone nozzle, spraying effect, liquid phase distribution, erosion on the tower shell