*3.4. Effect of Wastewater Initial Temperature on the Evaporation Performance*

Figure 13 shows the turbulence kinetic energy under different initial wastewater temperatures. By increasing the initial wastewater temperature, the turbulence kinetic energy in the mixing zone of the flue gas and the droplets changes slightly. Figure 14 displays temperature under different initial wastewater temperatures. Higher initial wastewater temperature corresponds to the higher temperature of the flue gas and the droplets in the mixing zone because the evaporation process of the wastewater droplet absorbs less heat under the constant input heat.

**Figure 12.** Effect of wastewater flow rate on evaporation performance.

**Figure 13.** Turbulence kinetic energy under different wastewater initial temperatures (m2/s2).

**Figure 14.** Temperature under different wastewater initial temperatures (K).

Figure 15 shows the effect of wastewater flow rate on the evaporation performance of the droplet in the spray drying tower. It can be seen that as the initial temperature of the wastewater increases from 298 to 348 K, the complete evaporation distance is reduced from 4.8 to 4.6 m, which is only 0.2 m. Additionally, there is no significant difference in the trajectory of the droplets under different initial wastewater temperatures. It can be concluded that the complete evaporation distance gradually decreases with the increase of the initial temperature of the wastewater, but the reduction degree is minimal. This is because if the initial temperature of the wastewater is higher, less heat is needed, and the evaporation temperature is reached quicker. However, this part of the heat only accounts for a small proportion of the heat carried by the flue gas, thus, the change of the initial temperature of the droplet has little effect on its complete evaporation distance. In the actual operation of the power plant, although the evaporation process of the desulfurization wastewater can be improved by increasing the initial temperature of the wastewater, its effect is minimal.
