Evaporation experiment and numerical simulation study of desulfurization wastewater in high-temperature raw gas

[Display omitted] •Optimization parameters of wastewater evaporation were obtained by CFD simulation.•An improved evaporation model of solution at high temperature was established.•The influence of gas flow on droplets dispersion was found.•The relationship between temperature and evaporation heat consumption was obtained.•The optimized injection system solved such problems as accumulated tar. This study adopts Fluent software to perform a numerical simulation on the evaporation of desulfurization wastewater, which is based on the experimental study of spraying desulfurization wastewater to the high-temperature raw gas (around 750 °C) inside the single riser of industrial coke oven. Regarding to the results, a further optimization was applied to the core-part nozzle structures of spraying wastewater in the experimental plant. The results indicated that the farthest distance of the droplets movement calculated by the modified formula We = f(T) was 0.051 m at 800 °C, which is more consistent with the experiment. When the flow rate of raw gas was increased from 0 m3/h to 700 m3/h, the dispersion degree of droplet particle trajectory was enlarged from range −0.181−0.174 m to −0.308−0.246 m on the x-axis, and the time that the droplet particles reached the gas flow rate accelerated from 0.007 s to 0.02 s. The relationship between the riser’s average temperatures before and after spraying desulfurization wastewater was T = 568.49In(T0) − 3151.9. It was consistent with the actual value. Within the coking time of 20 h, the average temperature of the riser after evaporation was 620.44 °C and the average evaporation time was 0.0025 s, when the desulfurization wastewater was sprayed at 3 m away from the water seal of the riser. The optimized injection system according to the simulation results has improved the treatment effect of the wastewater in the experimental plant.