脱硫废水在烟道中蒸发运动特性的数值研究

Numerical Study on Evaporation and Movement Characteristics of Desulfurization Wastewater in Flue Gas Channel

为了研究锅炉尾部烟道中脱硫废水的蒸发运动特性,建立了雾化液滴在烟气中蒸发和扩散的数学模型,利用数值模拟方法研究了脱硫废水雾化液滴在烟气中的蒸发过程,得到了蒸发过程中液滴平均粒径和蒸发距离等参数的变化规律,并比较了烟气和液滴性质对蒸发过程的影响。结果表明:液滴完全蒸发时间随烟气温度升高、流速增大、水蒸气质量分数降低、液滴初始粒径减小、液滴初速增大、初温升高、喷射角度增大、喷水质量流量减少而减少;液滴完全蒸发距离随烟气流速的增大先缩短后增加,当烟气流速为10 m/s时,液滴完全蒸发距离最短,其他因素主要通过影响液滴蒸发时间来影响蒸发距离,液滴蒸发距离与蒸发时间呈正相关。

An evaporation and diffusion models of the atomized particles in the flue gas were established to reveal the evaporation and movement characteristics of the desulfurization wastewater in the boiler tail flue gas channel.The variation rules of average droplet diameter,evaporation distance and other parameters were obtained in the evaporation process,and the effects of the flue gas and droplet properties on the evaporation process were compared through numerical simulation.Results show that the droplet complete evaporation time decreases with the increases of the temperature and velocity of flue gas,the initial velocity,initial temperature and spray angel of droplets,and the decreases of the mass fraction of water vapor,initial droplet diameter and water spray rates.The complete evaporation distance of droplets decreases first and then increases with increasing the flue gas velocity.When the flue gas velocity is equal to 10 m/s,the complete evaporation distance reaches its minimum.The evaporation distance may be mainly affected by other factors through the droplet evaporation time,which is positively related to the droplet evaporation distance.