火力发电厂湿法脱硫产生的脱硫废水处理难度大，脱硫废水烟道蒸发技术能够有效降低脱硫废水排放量，甚至实现脱硫废水零排放，进而降低电厂运行成本。为研究多喷嘴脱硫废水雾化液滴在锅炉尾部烟道中的蒸发规律，建立了脱硫废水雾化液滴在烟气内的传热传质模型。以某330 MW锅炉尾部烟道为研究对象，利用Ansys Fluent模拟研究了不同喷嘴数量时，烟气和雾化液滴性质对废水运动蒸发过程的影响。结果表明，当脱硫废水流量一定时，随喷嘴数量增多，单个喷嘴废水流量逐渐减少，使废水液滴在烟道内的分布更均匀，喷嘴上方的低温区域面积沿流动方向逐渐增大，平均温度和最低温度升高。在不同烟气和液滴性质条件下，随喷嘴数量增多，液滴的蒸发速度均增大，蒸发时间和运动距离缩短，但降幅逐渐变小，且液滴蒸发距离与蒸发时间正相关。此外，液滴运动速度几乎不受喷嘴数量变化的影响，液滴运动速度主要受烟气速度的影响。不同喷嘴数量时，随烟气温度升高、烟气含水量降低、液滴粒径减少、液滴初始速度初始温度增加，废水液滴的蒸发时间降低，蒸发距离缩短；烟气流速的增加降低了蒸发时间，单喷嘴时，蒸发距离先减小后增大，当烟气流速为10 m/s时，蒸发距离最短为9.85 m，多喷嘴时，蒸发距离一直减少。

The desulfurization wastewater produced by wet desulfurization in thermal power plants is difficult to treat, and the flue evaporation technology of desulfurization wastewater can effectively reduce the discharge of desulfurization wastewater and even achieve zero emission of desulfurization wastewater, thereby reducing the operation cost of power plants. In order to guide the practical application of flue evaporation technology of desulfurization wastewater, the heat and mass transfer model of atomized droplets in the flue gas was established to reveal the process of spray evaporation of desulfurized wastewater in the tail flue of the boiler. Taking the tail flue of a 330 MW boiler as the research object, the effects of flue gas and atomized droplet properties on the evaporation process of wastewater were studied with multiple nozzles by CFD simulation. The results show that when the number of nozzles is properly increased at a certain flow rate, the less the wastewater flow of a single nozzle, the more uniform the distribution of wastewater droplets in the flue,and the area of the low-temperature area above the nozzle gradually increases along the flow direction, the average temperature and minimum temperature increase.With different flue gas and droplet properties, the increase of the number of nozzles will make the evaporation speed of droplets faster, and the evaporation time and moving distance will be shortened, but the shortening range will gradually decrease, and the evaporation distance of droplets is positively related to the evaporation time. The number of nozzles has little effect on the droplet velocity, and the droplet velocity is hardly affected by the change of the number of nozzles, but the droplet velocity is mainly affected by the flue gas velocity. With different nozzle numbers, droplet evaporation time and distance decrease with rising of flue gas temperature, droplet jet velocity, droplet initial temperature and reducing of water vapor content, droplet initial diameter. The increase of the flue gas flow rate reduces the evaporation time. In the case of single nozzle, the evaporation distance first decreases and then increases. When the flue gas flow rate is 10 m/s, the minimum evaporation distance is 9.85 m. In the case of multiple nozzles, the evaporation distance is always reduced.

0 引言

1 脱硫废水雾化蒸发数值模拟

   1.1 数学模型

   1.2 物理模型及计算条件

   1.3 结果与讨论

2 影响因素分析

   2.1 烟气温度的影响

   2.2 烟气流速的影响

   2.3 烟气含水量的影响

   2.4 液滴初始平均粒径的影响

   2.5 液滴初始速度的影响

   2.6 液滴初始温度的影响

3 结论