脱硫废水旋转喷雾蒸发特性数值模拟

Numerical simulation of rotating spray evaporation characteristics of desulfurization wastewater

利用反应工程法(REA)建立脱硫废水液滴传热传质蒸发模型,分析液滴的蒸发过程,利用计算流体力学(CFD)方法将模型进行编程模拟计算,并利用该模型对某电厂600 MW机组的脱硫废水蒸发过程进行模拟,研究干燥塔进口烟气温度、处理废水量等蒸发工艺参数对干燥塔内流场和废水雾滴运动与蒸发的影响特性。研究结果表明:脱硫废水液滴在蒸发过程中存在等速和降速两个明显的蒸发阶段;进口烟气温度主要通过影响传热过程影响液滴群的蒸发效果,进口烟气温度越高,塔内沿程平均温度越高;处理废水量主要是通过影响传质过程影响液滴群的蒸发效果,处理废水量越大,塔内的湿度越大。

The evaporation process of desulfurization wastewater droplets was investigated based on the establishment of heat and mass transfer model for evaporation by reaction engineering approach(REA). The computational fluid dynamics(CFD) was employed in programming, simulation and calculation of the model. The model was applied in simulating the evaporation process of desulfurization wastewater from a 600 MW unit in a power plant. The influence of inlet flue gas temperature and wastewater treatment amount on the flow field and droplet evolution in the drying tower was studied. The results show that two obvious stages are observed during evaporation process, which are the stage of constant velocity and the stage of decreasing velocity. The inlet flue gas temperature affects the evaporation effect of droplet groups mainly by influencing the heat transfer process.The higher inlet flue gas temperature would lead to the higher average temperature along the drying tower. The wastewater treatment amount makes an appreciable difference in the mass transfer process, accounting for the impact on evaporation effect of droplet groups. With the increase of the wastewater treatment amount, the humidity in the tower grows higher.